This study attempts to assess the feasibility of building purposefully designed molecular motor arrays, the proteins responsible for the movements of the living organisms and cells. The 'building' process used high-resolution e-beam patterning, originating in semiconductor technology, upgraded to make biomicrolithography compatible with the patterning of bioactive molecules. The material used as a scaffold for the array [a copolymer of poly(tert-butyl-methacrylate/methyl- methacrylate)] was tailored to exhibit large difference in hydrophobicity when exposed to e-beam exposure. The e-beam patterning exposure-induced difference in hydrophobicity is responsible for the selective attachment of the myosin molecules on the patterned deep-submicron 'tracks,' and the higher concentration of 'guiding' molecules selectively confines the movement of the actin filaments.

The surface of photosensible diazo-naphto-quinone/novolak film was chemically manipulated through UV exposure and subsequent functionalization processes to obtain surfaces with different chemistries (DNQ, carboxylic, and peptidic groups). The neuronal cell attachment is controlled by three pairs of antagonistic surface variables: charged/uncharged species, amino/carboxylic groups and hydrophilic/hydrophobic balance, in which the former promote the adhesion. The study proves that microlithographic techniques in connection with surface functionalization with specific neuro-peptides can be used to build artificial networks with neuronal cells.

Recent developments in piezoelectric materials include submicron grain size ceramics and single crystals. Pb(Zr,Ti)O₃ (PZT) ceramics with submicron grain sizes (approximately 0.5 micrometer) have been produced with properties comparable to conventional, coarse grained (approximately 3 to 5 micrometer) ceramics. The fine grain ceramics exhibit improved machinability over conventional materials. Ultrasonic transducer arrays with post widths less than 15 micrometers have been fabricated as well as thin plates with thicknesses as low as 10 micrometers. The yields and performance of such operations are expected to be much greater with fine grain ceramic than with conventional material. The single crystal piezoelectrics developed offer field induced strain an order of magnitude higher than what can be achieved in piezoelectric ceramic actuators (greater than 1%). Furthermore, the strain electric field hysteresis and dielectric losses are very low for these materials and electromechanical coupling factors (k₃₃) are greater than 90%. Applications which may benefit from the recent developments include smart materials and structures and MEMS.

A piezoelectric wafer is here embedded in a glass fiber preform that is placed in a mould for resin transfer molding. The experiment displays that the resonant characteristics of a transfer function, in terms of the ratio between the electric voltage output from the piezoelectric wafer and the input to an electric circuit cascaded with the wafer, rely on resin injecting and curing process, and highlight the beginning/end of the resin injecting as well as the end of the exothermic reaction in composite manufacturing with the resin transfer molding. The relationships of the resonant response with resin flow and curing can then provide a basis of a prospective in-situ monitoring technique of the composite manufacturing. Further analysis reveals that the mechanical impedance, contributed by surroundings and associated with the resin flow, curing and exothermic induced temperature change, can be correlated with and even extracted from the transfer function amplitude at a frequency that is the same as the anti-resonant frequency of the piezoelectric wafer in air. It can further provide information about the flow front position and curing state of the resin.

Photoluminescenc eand electroluminescence of CaSiN₂:Eu materials were investigted to develop a new phosphor for thin film electroluminescence (TFEL) device applications. Ca₃N₂ and Si₃N₄ powders were mixed to form CaSiN₂ hostmaterials and Eu was added as the luminescent center. The mixed powermatrials were cold pressed under the pressure of 1 Kg/cm² to make pellets, and fired at 1400 degrees Celsius for 2 hours under N₂H₂ envrionemtn. Th ex-ry diffraction(CRD) patterns of synthesizd materals wer well matched with CaSiN₂ of joint committee for powder diffraction standards (JCPDS) csrad. When illuminated by ultravilet rays, th enew phosphors emitted very bright red ligh of peak wav lenegth centered at 620 nm. Th TFEL devices with CaSiN₂:Eu phosphor layser swre grown by sputter depositonof CaSiN₂:Eu target. Red light emission was observed when the peak amplitude of the applied voltge exceeded 116 V.l The luminance was shown to increase sharply withth increase of the applied voltage. The maximum luminance was 1.62 Cd/m² at the applied peak voltage of 276 V. The red emission from CaSiN₂:Eu TFEL device seems to result from electronic transition of Eu³⁺ ions.The emission spectra of TFEl devices matchwell withth ephotoluminescence spectra of CaSiN₂:Ey powders. The new devices structure and fabrication processes for the iimprovement of emission intenityof CaSiN₂:Eu TFEl devices ar under investigation.

A number of physical and optoelectronic properties of GaAs make it a highly suitable medium for optical smart sensors. In this paper, these properties are discussed with a view to smart image sensors (1) in a stand-alone context and (2) in the context of spatial light modulators (SLMs).

We have satisfactorily designed and prepared a gain-guided high-power 1.55 micrometer leaky waveguide semiconductor laser structure on the basis of considering the laser loss mechanisms such as auger electron recombination, carrier leakage over the heterobarrier, inter-valence-band absorption, etc. It was grown by a unique liquid phase epitaxy (LPE) and was modified by growing an intrinsic InGaAsP waveguiding layer between the active layer and lower confinement layer and provided a higher temperature stability than that of conventional lasers. Using the leaky waveguide structure, we have obtained 1.55 micrometer laser diodes with threshold currents comparable to common lasers (J_the less than or equal to 2.5 KA/cm²) but with the characteristic temperature T_O near to those of GaAs-AlGaAs lasers (142 K). Especially, we have obtained the peak output power up to higher than 2 W per facet in pulsed operation at room temperature.

The controllability of conductivity and the ease of manufacturing/coating of conducting polymers enable tailor- made dielectric loss components for radar absorbing materials (RAM). Different polypyrrole (PPy) based RAM, e.g. paint/rubber containing PPy powder and PPy coated structural phenolic foams with a gradient of impedance, have been examined. Reflection loss strongly depends on thickness and complex permittivity of the material. For a single layer material, the optimum values of the real part, (epsilon) ', and imaginary part, (epsilon) ", of the complex permittivity required to achieve a minimum reflectivity at a given sample thickness are found by theoretical calculations. The conductivity of the PPy powder is controlled to obtain RAM with lowest reflectivity according to the calculated optimum values of (epsilon) ' and (epsilon) ". A paint panel containing 2 wt% of the PPy powder with a thickness of 2.5 mm exhibits a reflectivity less than $minus 10 dB over 12 to 18 GHz. Blending and milling in the manufacturing process can destroy the original fibrous shape of PPy aggregates leading to low absorbing performances. PPy can be coated on rigid or flexible open cell foams to provide a lightweight broadband RAM. In particular, a coating technique on phenolic foams (12 - 15 mm thick) with a pore size of micrometer order has been developed to generate a gradient of conductivity across the foam thickness. The PPy coated foams are broadband RAM.

Novel dynamic, polymeric membrane structures have been successfully prepared and used in electrochemically facilitated transport and separation of proteins. A high purity of human serum albumin (HSA) can be separated from a mixture containing equimolar concentrations of HSA and Myoglobin. Quartz crystal microbalance studies show that, in these cases of transport and separation, the overriding controlling factor was electrochemical control, although polymer/protein interactions do affect the transport fluxes.

As part of a program focused on the development of selective conducting polymer gas sensors, we have investigated the behavior of polyaniline-platinum oxide chemoresistors in the presence of combustible gases such as hydrogen, methane, ethylene, acetylene and carbon monoxide. In this paper we report on results obtained using a polyaniline-platinum oxide sensor. By hydrogen atmosphere preconditioning, we were able to increase the selectivity and sensitivity of the sensors for hydrogen in air at concentrations between 1000 and 5400 parts per million (ppm).

Epitaxial growth techniques allow the precise growth of ultra thin semiconductor heterojunctions. The wave particle duality of electrons in such materials can be fully exploited in designing tailor made optical and electronic properties. The basic theory of electronic and optical properties of quantum wells described for the lattice matched GaAs/AlGaAs system. Optical modulation using the quantum confined Stark effect in p-i-n diodes and n-i-n phototransistors is described. Calculations showing the unique valence band warping effects in strained layer CdTe/CdZnTe quantum wells is presented. A CdTe/CdZnTe n-i-n optoelectronic device is described and performance discussed.

The suitability of refractory metal, molybdenum, as a material for microstructures in MEMS is explored in this paper. This paper describes the effects of dc magnetron sputtering conditions on the residual stress of the film. The effects of post deposition annealing as a means of stress relief are also reported. Post deposition annealing also addresses the problems of film adhesion. An example of the application of Mo is given in the form of a cantilever structure suspended over a silicon gap which involves both surface and bulk micromachining.

The titanium nitride film has been synthesized by electron beam evaporation depositino f titanium and bombardment with a xenon ion beam in th environment of nitrogen gas. The component, valence state and structure of titanium nitride film ar analyzed by means of XPS, AES, and X-ray difraction. The reslts shows that th main cooposition of the film are titnaium nitride crystallites with preferentia orientatinslightly and fine gran size,exept predominant titanium oxide film on surface of thefilm and there exists a signficiant mixed layser of titanium, nitrogen and ferrum between the film and its matrix, whichplayed an important role for increasing adhesion between the film and substrate. finally, its some properties have been investigated.

In this paper, we describe a method which we can identify 3D position and direction of ultrasound scanning probe inserted into inside of the body, which gives endoscopic images. We use marker transducers placed on surface of the body, which transmit pulses synchronized to the ultrasound scanner. The method of measuring position (direction and distance between scanning probe inside of body and transducer outside of body) of marker on the scanned image obtained with ultrasound endoscope by using adaptive threshold and robust algorithm is described. This system can be extended to for body-inside navigation by localizing body-outside transducers and visualizing the position and trace of the body-inside ultrasound probe. The final goal of the system is to reduce the x-ray dose in the endoscopic examination and to give direct 3D localization instead of the conventional 2D x-ray fluoroscopy.

Metastable CoCu thin films are deposited by rf magneto- sputtering. The relationship between magnetoresistance of CoCu granular films and vacuum annealing temperature, applied magnetic field, composition of alloy thin film are studied. FCC structure Co second phase are precipitated after annealing. Giant magnetoresistance effect is observed in the nonmagnetic Cu matrix, its magnitude depends on the quantity and size of Co particles. The structure of CoCu granular alloy films is investigated by x-ray and TEM method.

In this paper a detecting system that detects the errors of the dynamic angle measuring instrument has been developed. Theoretical analyses have been done on the detecting principles of the system. This new automatic testing system in which PSD instead of collimator can measure the dividing errors of the dynamic angular instrument. This detecting device overcomes the shortage of the collimator whose dynamic respond spectrum is limited in the course of dynamic testing. Moreover, this device has simple structure and is easy to adjust. The system consists of two-mode laser, a laser collimation system, rotating table, PSD and a 12-sides polygon mirror that was used as an angle standard. The optoelectronic position-sensitive detector (PSD) has the advantage of short respond time, high discrimination and large respond spectrum. But it has large position testing error. In this paper, the position testing error of PSD has got demarcating correction in order to meet the need of high precise measurement. This device can work in high speed. Its accuracy is high in the dynamic testing. With the system, a preliminary experimental research has been made on the round synchronous transformer. Experimental results show that the system satisfies the initial design requirements.

In our paper, a theoretical treatment which includes a new and effective numerical method is proposed. It is used to nondestructively reconstruct the depth distribution of optical absorption coefficient in multilayer inhomogeneous material, through by the photothermal signal which is related to the surface temperature of a sample and measured with the photothermal method. Numerical simulations demonstrate the performance of the approach is better.

The effective d₃₃ of sub-micron piezoelectric polymer films, deposited on glass substrates, has been measured using an optical interferometer. The polymers used were polyvinylidene fluoride (PVDF) and copolymers of PVDF with trifluoroethylene (TrFE). The interferometer measures movement of the polymer surface, in response to an applied electric field, and is easily able to detect motion of 0.1 nm. In this situation, the rigid glass substrate effectively clamps the soft polymer film in the lateral direction. Nevertheless, effective d₃₃ values approaching 10 pmV^-1 have been observed. One advantage of such thin films, is the ability to pole them with quite low voltages. For example a 100 nm film can be poled by 10 volts. The low voltage required to achieve poling in such thin films, means that the poling voltage can be left permanently connected, thus maintaining the piezoelectric activity. By adding a periodic bias voltage to the driving signal, it is possible to observe hysteresis in the piezoelectric coefficient, corresponding to the polarization hysteresis loop. The piezoelectric coefficient shows an abrupt change in sign at the coercive field, corresponding to the reversal of the net polarization.

Dielectric loss in a piezoelectric ceramic transducer is concerned with the vibration, and increases remarkably under the high-power operation even in a so-called hard PZT. When ordinary hard PZT ceramics is used over the vibrational velocity of about 0.25 (m/s), the dielectric loss becomes larger than the mechanical vibration loss. In the paper, a new advanced measurement method for obtaining simultaneously both the mechanical loss and the dielectric loss of the piezoelectric ceramic transducer under high-power operation is described. At the resonance frequency, the dielectric loss and the mechanical vibration loss can be separately and simultaneously measured. In the study, some experimental results have been obtained and evaluated with respect to the accuracy. These results are very useful for the precise design of the piezoelectric power devices.

The preparation of a new polyaniline-based PVC composite is described. The composite is made by surface treatment of the PVC, followed by coating of the PVC particles with a m-cresol solution of polyaniline doped with camphor sulfonic acid. The composite possesses a low percolation threshold (less than 0.125% weight fraction) and significant conductivity at low loadings. The microwave properties of the composite have been studied and results indicate the material has potential as an EMI shielding material and in the construction of novel microwave devices.

The discovery of new sensing materials and electrodes has greatly expanded the range of scientific methods including electrochemical techniques. Conducting polymer such as polypyrrole and polyaniline represent a new class of organic polymers that are capable of molecular interactions and being able to interact, chemically or electrochemically, with the species of interest for detection. Although these conductive materials have unique properties they have their specific problems with respect to their reproducibility and reusability. Problems exist due to the dynamic nature of these polymers thereby mitigating against their successful applications as novel sensors. This has also hindered the production of analytical useful, sensitive, and reversible signals using these polymers. This paper has sought to examine the problems due to the lack of useful analytical, sensitive, reversible and reusable signals through the introduction of new series of integrated artificial intelligence/conducting polymer based sensors. In these types of sensors analytical responses, which look irreversible and nonreproducible, are combined by an artificial intelligence trained computer by which reproducible output can be predicted based on the created model and pattern by the computerized system.

This paper considers the impact of segregation on the charge transfer at the oxygen/zirconia interface. Specifically, the effect of segregation-induced low dimensional interface structures on the performance of electrochemical devices based on zirconia as a solid electrolyte is discussed.

A micro membrane vibrator consisting of bimorph cantilever beams and a membrane is designed, fabricated, and tested here. Due to the discrepancy of thermal expansion coefficients between different layers, the membrane moves with temperature change. The four-layer structure including SiO2-polysilicon- insulated SiO2-aluminum is fabricated with four masks. The numerical finite element program ANSYS 51 is used to investigate the behavior of different designs to have larger displacement and force. According to the testing results, we observe that our designs can induce the maximum Z-axis displacement up to 117 micrometer when input power is 6.98 W. The working frequency is about 40 Hz when the amplitude is kept between 2 and 5 micrometer approximately.

A sheathed silicon optical fiber probe was used to observe the radiance in explosive combustions. The utility of such probes was demonstrated by placing them both inside and in the vicinity of the explosion's fireball. H-6 composition (100 g of RDX/TNT, 60:40 ratio mixed with aluminum) was used. It was shown that the probes were capable of surviving the hostile environment in the presence of shock waves and temperatures (2,000 - 3,000 degrees Celsius) beyond the melting point of silicon glass. This paper describes the use of a light pipe radiometer consisting of a silicon optical fiber cable which has a core/outer diameter of 62.5/125 micrometer and the steel conduit (20 mm diameter) that was used to firmly hold it. The advantages of such a probe are that it allows the use of very high speed photodetectors (InGaAs PIN photodetector, with bandwidth of 10 kHz - 125 MHz, rise time 3 ns and operating wavelengths in the range of 800 - 1800 micrometer). The low cost, readily available probe was insensitive to pressure and has a very high resistance to the effects of shock waves. This device provides a radiant measurement technique that can be applied in situations where cameras can neither reach, nor afford to be destroyed. The disadvantage is that the fiber facet may become coated by opaque combustion products which tend to interfere with the radiant reading. This technique is particularly suitable for cross examination of explosive combustion where a number of such probes are employed in an array. It can also be used to monitor the presence of burning particles within defeated armours and hence via their irradiance, to determine the danger to personnel.

Electron-beam lithography employing poly(tert-Buthyl- Methacrylate)-co-(Methyl-Methacrylate) as radiation sensitive system was used to pattern bioactive molecules at super-high resolution. Positive and negative tone lithography succeed in printing fluorescent avidin into the range of 100 nm resolution. Two mechanisms were used for protein attachment, namely: (1) the linkage of the amino-end of the protein to the radiation-induced carboxylic acid sites, via NH₂-to-COOH crosslinking mediated by carbodiimide; and (2) hydrophobic interaction between the patterned proteins and unexposed surfaces, in contrast to hydrophilic-repulsive interaction with exposed one. The first mechanism produces positive tone, half-tone images, while the second produces negative tone, sharp contrast images. On this basis, we assume that the first mechanism is concentration-controlled, while the second is an on-off one. This study proves that e-beam lithography materials and techniques can be easily transferred in bio- microlithography, with impact on biodevices fabrication and combinatorial chemistry.

By introducing an interaction energy function, the first two of the present authors proposed a one-dimensional pseudoelastic theory of shape memory alloys, which has been demonstrated to model complicated experimental results and Tanaka's transformation kinetics qualitatively well. To study the stress-strain-temperature relationship, we further develop the pseudoelastic theory by introducing temperature-dependent terms in the free energy function proposed by Ranieki and Bruhns. In addition, the effect of temperature is included in the interaction energy. For computational analysis, material parameters are estimated from data measured by Tobushi and his coworkers in their experiments. Numerical results show that predictions by the present theory agree with some essential feature of their experimental results.

A number of techniques are available which will enhance residual static strength and fatigue life of metallic components. In the case where a crack exists a simple method is to stop drill the crack tips. More elaborate techniques consist of stop drilling the crack tips, cold expanding the resultant hole and inserting an interference-fit plug. The application of bonded composite repairs to cracked metallic structures has also become an accepted technique to enhance strength and fatigue life of cracked metallic components. This paper looks at the possibility of using smart materials such as shape memory alloys (SMA) for the life enhancement of metallic structures. An investigation into the use of SMAs was completed using finite element modeling of one particular concept known here as the annular SMA repair which was presented as one method of possibly increasing the fatigue life of holes. From the results given in this paper it was shown that the inclusion of a SMA ring, interference fitted into a machined annulus in an aluminum plate, induces a significant compressive stress around the boundary of a hole. Also, discussed are other ideas which use SMAs for repairing cracked metallic components. Although the current studies are only conceptual and qualitative they do illustrate the feasibility and potential of such techniques to enhance strength and fatigue life of metallic components.

We report on civil engineering applications of a fiber optic distributed strain sensor. It consists of a sensing fiber and a high performance optical time domain reflectometer (OTDR), for measuring both strain and optical loss distribution along optical fibers by accessing only one end of the fiber. The OTDR can measure distributed strain with an accuracy of better than +/- 60 X 10^-6 and a high spatial resolution of up to 1 m over a 10 km long fiber. In model experiments using the OTDR, we measured the strain changes in fibers attached to the surface of a concrete test beam. The performance of the fiber strain sensor was tested by measuring the strain distribution in optical fibers and comparing the results with resistance strain gage measurements for several loads. We found that the two sets of results were similar, and in addition, we demonstrated experimentally that the sensor was able to measure an induced strain change of less than 100 by 10^-6, which is nearly the elastic limit of the concrete material. These results show the potential of the OTDR to extend the application of monitoring systems to such areas as large building diagnostics for civil engineering.

The modeling and formulation of simultaneous optimization problems with H₂ and H_(infinity / norm objective functions are discussed in the paper. They are applied to the simultaneous optimization of the cross-sectional parameters of a spring- supported beam and the parameters of the controller used to actively suppress the vibration of the beam. The H₂ and H_(infinity ) norms of the transfer function from external disturbance to measured output are used as the objective functions. Simultaneous optimization is realized by iteratively executing structural optimization and controller optimization. Both serial and parallel approaches to combine structural optimization and controller optimization are investigated. The performance of both output and control input is improved significantly after simultaneous optimization. The simulation results show the great potential advantages of simultaneous optimization over traditional design methods.

Structural vibration suppression is of great interest to the aircraft industry as it can reduce the amplitude of excessive vibration in lightly damped panels caused by conditions in their operational environment. One technique of suppressing vibration is to use passive damping techniques such as constrained layered damping incorporating viscoelastic materials. However these techniques may not be acceptable because of weight concerns or extreme temperature variations. Over the past decade much work has been done by researchers on the use of piezoelectric ceramic devices, using passive and active techniques, for structural vibration suppression. The passive piezoelectric damping devices consist of a piezoelectric element and either a resistive or resonant shunt. The resonant circuit shunt, which is analogous to a mechanical vibration absorber, gives better vibration reduction compared to the resistor shunt. This device requires a large value of inductance in order to be tuned to a particular structural vibration mode. A large value inductor can be made by a using a gyrator type circuit however the circuit needs external power. A method of vibration control using a discrete time controller and piezoelectric devices is presented. That is, this paper describes the concept of a self-powered discrete time piezoelectric vibration damper which does not need tuning to the structural resonant frequency and is powered by piezoelectric elements, i.e. does not need an external power supply. This device is referred to as a strain amplitude minimization patch (STAMP) damper. A brief description of the theory used and of the scheme is presented. Also the operation of this device is compared with other 'passive' techniques, involving piezoelectric elements, such as the resistive passive damper and the parallel resonant passive damper cases. Experimental results presented, on a cantilevered beam, demonstrate the concept and show that the device, even in its current underdeveloped form, has better damping than the simple resistor damper. Measurements taken indicate that the maximum RMS tip accelerations, at resonance, are reduced by 17.3%, 62.7% and 39.5% for the resistor, parallel resonant and STAMP damper devices, respectively, when compared to the short circuit reference condition. The performance of each device is observed when the resonant frequency of the system changes when a mass is added to the tip of the cantilever. This paper also discusses areas where improvements in the performance of the STAMP damper can be achieved.

In this paper, an emphasis is put on investigations for effectiveness of hysteretic dampers introduced to stiffness and strength asymmetric frame structures. To avoid large displacements caused by torsional responses at the flexible- edge of the structures, reductions of eccentricity are aimed on general designs of the asymmetric structures. The concepts of those structural design are based on what dynamic behaviors of building structures limited within elastic regions, so that, inelastic behaviors of stiffness and strength asymmetric frame structures are not considered sufficiently. To consider to inelastic behaviors of asymmetric frame structures by installing hysteretic dampers, numerical simulations are executed. As a result, it is assured that, by adequately locating of hysteretic dampers to the asymmetric frame structures, inelastic structural responses regarding to the maximum displacements can be reduced to the same level of those of symmetric frame structures.

Optical fibers are used in smart structures mainly as sensor elements and communication links. Fiber Bragg grating (FBG) based sensors have become the most popular ones among all the fiber sensors. For distributed measurement, the sensing network is required to cover as much area as possible. Also, the sensors are required to be placed as closely as possible to achieve a better surface-scanning. These together necessitate the need for a number of sensors to be incorporated in one fiber line, something restricted in practice by the individual sensor response and the source bandwidth. In this paper, a theoretical analysis of Bragg gratings, in isolation and in an array is presented. An existing theory of FBG has been revisited with a view to reduce the sensor's bandwidth. Effect of inclusion of second derivatives and cladding modes in the coupled mode theory used here is explained. For a typical 4% Ge doped single mode fiber, FWHM of a grating is found to be 1.7 nm as against 3.7 nm, when no such modification is done. Uniform grating array is preferred over the non-uniform type, from the fabrication and signal processing point of view. But for an array consisting of a large number of uniform gratings, addressing each sensor element becomes the problem. An array of non- uniform cluster of uniform gratings can be a good remedy for this. The number of gratings in one cluster is a trade-off between the measurement and signal-processing ease.

This paper concerns the shape control of composite material plates using piezoelectric actuators. A finite element formulation is developed for modeling a laminated composite plate that has piezoelectric actuators and sensors. To improve the accuracy of the prediction of the plate deformation, a simple higher-order deformation theory is used. The electrical potential is treated as a generalized coordinate, allowing it to vary over the element. For the shape control, an optimization algorithm, based on finite element techniques, is developed to determine optimal actuator voltages to minimize the surface error between the desired shape and actual deformed shape. The error function for a plate element is determined by calculating the mean square of the surface error over the surface, instead of determining it only at the node points of the element. Based on these techniques, Matlab codes were developed. Analyses were performed to determine optimum actuator voltages. The analytical results demonstrate the feasibility of using piezoelectric actuators for the active shape control of spacecraft reflectors.

The aim of the paper is to propose a distributed control technique based on the modal coupling between a beam and an electric transmission line with PZT actuators; these last behave as capacitances in the electric line and contribute to beam stiffness because their end-points are restrained along the beam; we call the described system a piezoelectro- mechanical (PEM) beam. Structural control by means of concentrated devices often requires high voltages and high inductances; this fact is particularly serious when one has to deal with PZT actuators; in order to overcome the problem we propose a device in which the control action is distributed along the beam. We found that the line inductance and the line resistance behave as electric 'taps' respectively for the electro-mechanical modal coupling and for the damping efficiency: we found a bounded region in the line impedance plane in which the energy exchanged between the beam and the electric line is maximum and therefore the control strength is maximum. By means of already available PZT actuators we obtain very high damping ratios for mechanical vibrations ((delta) approximately equals 0.1). We only investigated a simple case of passive control in damping vibration, but several active control applications are conceivable: it seems to us that such control technique is more efficient than those already proposed in the literature characterized by the use of actuators supplying concentrated forces.

After establishing the basis for assessing the structural implications of introducing a widespread sensor architecture in laminated composite materials in order to precisely identify and locate damage, the paper addresses the problem of structural diagnostics with a discussion of the development of several optical sensors. The research project will first investigate a passive optical fiber impact sensor to be implemented in the matrix of a composite material used in aeronautic and automotive applications. The senor's operating principle is based on the changes in propagation conditions occurring in a fiber subjected to transverse compression: under these circumstances, structural microdistortions produce local energy losses and hence a reduction in the optical power which propagates in the fiber and can be measured at its opposite end. As optical power losses also take place as a result of micro-bending of the optical fiber's longitudinal axis, a preliminary feasibility study will measure power attenuation versus fiber curve radius as the first step in the development of an optical fiber delamination sensor which locates separations between the layers of a composite material, i.e. debonding of sandwich panel core faces. Finally, an active impact sensor will be developed which uses optical fiber's sensitivity to pressure changes to detect the pressure gradient caused by an approaching vehicle or obstacle. The automotive industry will be able to make strategic use of these sensors, for example by installing them on vehicle sides to active the side airbag in the event of impact or collision.

The results of our analysis of a set of lead zirconate titanate (PZT-5H)/hard polyurethane 1 - 3 piezoelectric composites produced by injection molding are presented. Two groups of samples with 15 and 30 volume percent PZT were analyzed using impedance resonance techniques. Results from the thickness, radial, length thickness, thickness shear, and the length extensional modes allow the determination of the effective material constants. The complete effective (s^E, d, (epsilon) ^T) matrix is presented for the two compositions. The limitations of using resonance techniques to determine composite material properties are discussed.

The issues of processing and evaluation of pultruded smart composite reinforcements with embedded fiber optic sensors are discussed. The required modification of the pultrusion processing technology to allow for the incorporation of fiber optic sensors is developed. In order to fully evaluate the loads imposed on the Fabry Perot fiber optic sensors during the pultrusion process, the strain sensors were subjected to the separate variables of the total process. The following data was obtained for the carbon fiber rods. Compaction pressure alone caused negligible residual strain. The temperature profile caused a similar strain profile over the length of the pultrusion die. For the total pultrusion process, the residual strain after cooling appeared to present somewhat of a problem. For several experiments, the residual strain after exiting the pultrusion die was in the range of plus 200 to 400 microstrain, after which the sensors ceased to function. Calculations indicated that the radial shrinkage of the carbon fiber rods may have been sufficient to cause failure of the Fabry Perot sensors. A special procedure of reinforcing sensors prior to embedding them into the composite was successful in allowing the sensors to survive with only a slightly negative residual strain.

In this paper, a fiber optic modal domain sensor system for the evaluation of bridge pavement samples is developed. The sensing principle based on intermodal interference is analyzed. The method of embedding and surface-mounting sensors within or on the concrete pavements is presented, and the test results of the pavement samples are given. The experiments show that the fiber otpic sensor system is an effective means for evaluating concrete pavements and monitoring the cracks and damage of concrete structures in-situ.

A noble torsional actuator that will produce somewhat large rotational angle is developed. The actuator comprises of a piezoelectric torsional actuator and a torsional resonator. The piezoelectric actuator is specially designed such that the resonance frequency of the first torsional mode coincides with the external excitation frequency. The torsional resonator is made with torsion bar, and the resonance frequency of the bar is also matched with that of the piezoelectric actuator. By matching these natural frequencies, large torsional amplitude is generated. Theoretical and numerical works to design such a device are performed. For a special application, for example, laser scanning unit (LSU), the instantaneous rotation angle of the device is controlled such that a desired trajectory is generated. The development of such device will results in substitution of the conventional polygon mirror in LSU with the new device, and high speed laser printing could be possible.

This paper presents a technology to design and fabricate sensor array using separate sensors or individual sensory devices for distributed sensing in smart structural systems. It reports in detail on a non-integrated piezoelectric passive sensor array, which is constructed of separate piezoelectric devices along the spatial distribution of the measurand. As piezoelectric sensory devices can be used as self-generating sensors, the piezoelectric sensory array will sense passively without power supply. The sensor array consists of an X-Y matrix of m X n piezoelectric elements accompanied by diodes. The space of sensory elements ranges from 0.1 meter to several meters and the external connections of the sensor array are m + n. The array is addressed as a memory and the sampling signals of analog sensing outputs of the elements can be taken out as a serial wave form to a single output port of the array. It is also possible to read the analogy output of one element by sustaining addressing of it. A description of the arrangement and control of the array is presented, in addition, the electric response to mechanical input of piezoelectric sensory element is also analyzed to determinate the design of feasible preconditioning circuits for the sensor array.

In order to solve the problem of demultiplexing FBG sensors for smart structures, an image spectrometry scheme is proposed. The principle of this scheme is analyzed and the main feature of the system is derived. The experimental setup and results are presented. The multiplexing capacity of the system is calculated on the basis of experimental result.

Yield point is one of the most important mechanical properties of materials, however, there have not been any rules for obtaining the yield point caused by cyclic loading. Also in the case of analyzing the fatigue phenomena, the mechanical properties obtained by tension testing are normally used. It is widely known that when a tensile load is applied to a plane carbon steel specimen, Lueders' lines corresponding to yield stress occur on the surface. We decided to utilize Lueders' lines, in order to obtain the yield point under cyclic loading, therefore we investigated the state of their surface. Then it was clarified that we can utilize Lueders' lines in order to detect the yield point caused by cyclic loading. And that is used to detect the failure place of structural members. This method is very easy, namely only to have a smooth finish at the fixed portion, we can observe an occurrence of the striped pattern by the naked eye.

A torsional mode frequency tunable electrostatically driven resonator is presented. The resonator is designed using the simple linear elastic theory and fabricated by a bulk- micromachining technique. A bias voltage generates an electrostatic vertical force, then induces a bending moment in the torsional spring. The bending moment increases the torsional rigidity equivalently. Thus its natural frequency of oscillation is controlled by changing the bias voltage. A preliminary measurement of the resonator shows a natural frequency shift from 135.85 Hz to 136.10 Hz by the application of a bias voltage of 100 V. The theory, construction, fabrication process and demonstration of the resonator are presented.

The reflective fiber-optic sensing is a well-known method, and widely applied both to displacement measurement and pressure measurement. Although this type of sensor has many advantages, the sensitivity of the sensor is liable to be affected by several sources of error: the variation in the intensity of the light source, the changes in the reflectivity of the target and other error sources. A new compensation method is described in this paper. It provides a useful method to compensate the effects of the error sources listed above. The sensor works with two fibers arranged perpendicularly to the reflecting surface. One is Y model with three ends, one of which is coupled with a laser diode so that the light from it can reach the reflecting surface through the second end, another end is used for receiving. The other fiber put near the Y model fiber is a typical one for receiving. The two received intensities do division, the ratio of them is a function of the distance D between the measuring end and the target, it is independent on the characteristics of the light source and the target reflectivity. Many experiments have been done to test this conclusion, the resolution of this sensor can reach 0.01 micrometer.

This paper considers the impact of segregation on the charge transfer at the oxygen/zirconia interface. Specifically, the effect of segregation-induced low dimensional interface structures on the performance of electrochemical devices based on zirconia as a solid electrolyte is discussed.

This paper studies the forsed vibrations in a perfectly conductive plate in a non-contact way of exitement. It is proved, that by the help of constant magnetic field, it is possible to pass the forced vibrations of one plate, which is under the function of disturbulent force, to another, which is free from mechanical load, in a non-contact way. By the choice of appropriate parametrs of the problem, we can reach to an effect, when, on the whole, vibrates only the second perfectly conductive plate, which an adjustive amplitude. Analogous problem in case of superconductive plates is examined below [5].

This paper reports on the design and fabrication of surface acoustic wave (SAW) devices using lithium niobate (LiNbO₃) as a substrate. Sol-gel prepared doped TiO₂ thin films have been deposited onto the SAW devices by spin-coating. Modeling and simulation has been performed to predict the performance of SAW oxygen sensor using a high frequency electronics computer software package (HP-EEsof^TM). Experimental work has been carried out for the purpose of evaluation of the simulated results. Resistivity of doped TiO₂ thin films has been found to decrease by 47 fold when oxygen concentration decreases from 1% to 1 ppm at a working temperature of 200 degrees Celsius. The frequency shift of the SAW oxygen sensor has been measured as 180 kHz for the same change in oxygen concentration. Our preliminary experiments highlighted that the doped TiO₂-coated SAW sensors can detect oxygen in the concentration range of 1 ppm-1%.

The composite structures with embedded optical fiber sensors construct a smart composite structure system, which may have the characteristics of the in-service self-measurement, self- recognition and self-judgement action. In the present work, we studied the microstructures of carbon/epoxy composite laminates with embedded sensing optical fibers, and the integration of optical fiber with composites was also discussed. The preliminary experiment results show that because of the difference between the sensing optical fibers and the reinforcing fibers in their size, the microstructure of the composites with embedded optical fibers will produce partial local changes in the area of embedded optical fiber, these changes may affect the mechanical properties of composite structures. When the optical fibers are embedded parallel to the reinforcing fibers, due to the composite prepregs are formed under a press action during its curing process, the reinforcing fibers can be arranged equably around the optical fibers. But when the optical fibers are embedded perpendicularly to the reinforcement fibers, the resin rich pocket will appear in the composite laminates surrounding the embedded optical fiber. The gas holes will be easily produced in these zones which may produce a premature failure of the composite structure. The photoelastic experiments are also given in the paper.

The ionic conductivity and sensitivity of a series of Ce⁴⁺-doped zirconia thin film synthesized by sol-gel process are studied. The conductivity of the film is mainly depended on the doping ions and its concentration. The result shows that the ZrO₂(Ce⁴⁺) solid solution is well suited to maintain the ionic conductivity in a wide composition range. A physical model has been proposed to explain the high sensitivity of the thin film.

This paper presents the results of our investigation on deposition and characterization of sol-gel prepared TiO₂ thin films for oxygen sensing applications. The properties of pure TiO₂ thin films are compared with those doped with niobium oxide and 1%pt. These films are characterized using Rutherford backscattering spectroscopy (RBS), x-ray diffraction (XRD) and scanning electron microscopy (SEM) to study their chemical composition, structure and surface morphology respectively. Both kinds of the films are stoichiometric. Pure TiO₂ as well as doped films were amorphous as deposited. Pure TiO₂ films after annealing to 450 degrees Celsius and above showed the formation of anatase phase, while the doped films still predominantly amorphous, barely showing the onset of crystallinity. Pure films after annealing to 600 degrees Celsius appear to have become granular and porous. Doping with niobium oxide and Pt resulted in modification of film microstructure also. As a result of doping, the gas sensitivity of the films is increased from 8 to 24 and operating temperature decreased from 320 degrees Celsius to 190 degrees Celsius.

Smart materials functions often mimic biological functions. Recent basic research at the U.S. Army Research Office has focused on biomimetics and meso-scale smart materials. Current ARO materials research interests and progress in these areas are reviewed for sensors, molecular recognition, signal transduction, structures and control functions.

Conduction polymers such as polypyrrole and polyaniline are being extensively studied for their use in a wide range of new products. These materials are unique in that they have switchable properties due to their 2 or more mechanically stable oxidation states. Thus, films or coatings can be easily switched by the application of small voltages and currents to change the mechanical and electrical properties, the density, light absorbance and even to emit light in a diode arrangement. This paper discusses the factors that influence the performance of conducting polymers in four applications being developed at the Intelligent Polymer Research Institute: actuators, membranes, sensors and corrosion resistant coatings.

Optical fiber-based sensor instrumentation has been used extensively for the measurement of physical observables including strain, temperature and chemical changes in smart materials and smart structures, and have been integrated with MEMS devices to provide multi-measurement capability along the length of a fiber link or network. This plenary paper briefly outlines recent developments in such optical fiber sensor instrumentation. Fiber optic sensors are small in size, immune to electromagnetic interference and can be easily integrated with existing optical fiber hardware and components that have been developed primarily for use in the larger telecommunications market. Such sensors can be easily multiplexed, resulting in networks that can be used for the health monitoring of large structures, or the real-time monitoring of structural parameters required for structural analysis and control. This paper briefly describes and compares three current fiber sensor configurations that use Fabry-Perot interferometry and fiber Bragg gratings (FBG) and long-period grating (LPG) elements to monitor strain, temperature and other parameters. Extensive details concerning additional related work and field test results and applications are discussed in the references.

Since inception 16 years ago, the MOSIS Service at the Information Sciences Institute of the University of Southern California has processed over thirty thousand (30 K) IC Designs. Three years ago, it added access to commercial multichip module (MCM) fabrication through MIDAS. To the list of standard offerings, MOSIS now introduces back end processing of MOSIS custom VLSI circuits for both suspended structure and diaphragm style MEMS. MOSIS presents an array of high-end VLSI technologies from various domestic foundries' standard processes for prototype and small volume quantities. Thus designers can develop low-cost ICs, MCMs and (now) MEMS with a one-stop-shopping electronic commerce style service. MOSIS functions as a 'transparent' third party interface between design and fabrication. The service offers ease of use through supported standard cell libraries and design tools, and with Internet design submission. Sharing the costs of NRE, masks and fabrication provides a low cost environment for users. MOSIS handles the front-end foundry tasks of data preparation and mask fabrication with fixed domestic and international price lists. MOSIS utilizes volume production lines at AMI, HP, Orbit, Vitesse, and MicroModule Systems (MMS). This paper discusses what MOSIS offers to the VLSI design community, various applications fabricated through the service, as well as a conceptual design that draws from the various technologies discussed.

Photostimulated luminescence (PSL) in Eu and Sm co-doped II-VI compound phosphor ceramics such as SrS and CaS is studied in order to develop a smart erasable and rewritable optical memory utilizing PSL phenomenon. Intense PSL with a peak at about 600 nm and 650 nm is observed, respectively, in SrS:Eu,Sm and CaS:Eu,Sm posphor ceramics which are stimulated with infrared light after irradiation with ultraviolet-(UV) light or visible-light. The PSL characteristics of SrS:Eu,Sm posphor ceramics for the optical memory are reported. The OR Boolean logic operation is demonstrated using the PSL phenomenon in photostimulable phosphor materials.

The wide application of composite materials is a distinctive feature of modern technologies. This encourages scientists dealing with radio physics and optics, to search for new type of artificial materials. Recently such investigations have shifted in the field of materials with weak spatial dispersion: chiral, omega materials, artificial magnets, etc. By weak spatial dispersion we mean that the constitutive relations are still local but constitutive parameters depend upon a wavenumber k. It is the dependence that is responsible for non-encountered-in-nature properties of the materials such as chirality [a first order in (ka) effect] or artificial magnetism [a second order in (ka effect)]. Here a is a typical size of an inclusion. Certainly, all these effects are small enough unless there is a resonance interaction of electromagnetic wave with an inclusion. Near the resonance frequency the effects are significant and perturbation theory in (ka) fails. Nevertheless it is convenient to describe the effects in terms of orders in (ka), understanding this as a matter of classification. In spite of physical clarity of the classification the constitutive relations are treated in terms of multipole expansion. The multipoles naturally appear at field expansion in (d/R) where d is the source size and R is the distance between the source and recorder. Such an expansion is useful in 'molecular optics' approximation where d very much less than r, with r to be a mean distance between the 'molecules.' Though the 'molecular optics' ceases to be a good approximation if we deal with composites where d approximately equals r, the mean current in the right hand side of the Maxwell equations is still expressed through multipoles (see Fig. 1). Below we consider the reasons justifying this sight on things even if we are working beyond the 'molecular optics' approximation. To repel an accusation in abstract contemplation let us consider examples of the 'multipole' media. Permeable composites made of non-permeable ingredients are well known. The simplest example is a composite loaded with highly conducting spherical inclusions. Due to eddy currents there appears a magnetic moment of the inclusion and the composite exhibits properties of diamagnetic. The inclusions of more complicated structure can exhibit resonant excitation resulting in induced magnetic moment. Examples of such inclusions are open rings, dielectric spheres, helix and bi-helix. In this case depending upon the relation between the working and resonant frequencies we can observe both diamagnetism or paramagnetism. Q-medium is more smart system. As the system of identical dielectric spheres is a permeable material, the system of different in size spheres may be non-permeable. The concentrations and radii may be chosen so that one part of spheres is excited in diamagnetic mode and the other in paramagnetic. Such a system is described by its quadrupole moment (see Fig. 1). Putting quantum mechanics apart we shall consider a classical composite material. The adjective 'classical' means that the scale of inhomogeneity is large enough to describe the reply of material on electromagnetic disturbance in terms of local constitutive equations D_i equals (epsilon) ((omega) ,r)E_j j_i equals (sigma) ((omega) ,r)E_j where (epsilon) ((omega) ,r), (sigma) ((omega) ,r) are local permittivity and conductivity.

Surface micromachining fabrication process offers a novel approach for realizing micro-optical system onto a chip. A new micromachined micro optical filter which relies on intensity changes due to the interaction between a light beam and the optical shutter has been designed, fabricated and tested. The micro optical filter consists of a 2 micron thick polysilicon shutter suspended from the substrate by springs which are 200 micron long polysilicon folded beams. The sacrificial layer which is sandwiched between the silicon substrate and the structure is removed with a hydrofluoric acid wet etch, and a self-assembled monolayer coating is used to prevent friction. The filter is designed as a mass-spring system that moves in response to acceleration force. An application of accelerometer with higher sensitivity in a lower acceleration range is expected.