Zinc oxide thin films were deposited onto chromium coated silicon dioxide wafers using Single Source Chemical Vapor Deposition (SS CVD). The physicochemical properties of these films were then characterized using X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The physicochemical profile generated from these measurements was then compared to the piezoelectric properties of the films. The piezoelectric d₃₃ coefficient of the films was determined using Optical Interferometry and Atomic Force Microscopy (AFM). It was found that the AFM measurements gave a d₃₃ piezoelectric constant of 12 +/- 3 pm/V whereas the interferometric measurements yielded a d₃₃ of 0.45 - 1.21 +/- 0.10 pm/V. The difference between these two values highlighted the need to distinguish between Local Piezoelectric Response (LPR) and Global Piezoelectric Response (GPR) and the factors such as crystallinity and sample handling which can affect both. Unlike sputtered films, the results for SS CVD film suggest that the carbon impurities within the film appeared to have an effect in orienting the polarity of the crystallites.

Like natural biological building systems these materials are inexpensive, and self-form through interaction of the materials. They sense and self-repair, respond to changes in the environment. The volume and scale, cost and end use are all considered from the start. The purpose of the particular system we will describe is an engineered bridge. The materials form as bone does from the innate attributes of the material without much labor. They sense the environment, respond to it, and repair any damage. This composite bridge is designed from a self-forming polymer and concrete system. Internal release of chemicals, their properties and location account for responsiveness to change and for repair. The choice of matrix additives also allow for the responsiveness. Bridge frames were fabricated for dynamic testing. The results showed that self repair and response to loads could be accomplished by careful placement of chemicals for later release and by use of chemicals which could alter such attributes as stiffness, flexure and permanent deformation. Internal viewing sensors could determine the state of the frames after testing.

This polymer ceramic composite is biomimetic in that it follows the rules of bone growth for superior properties of strength and toughness. There is an intimate mechanical and chemical bond which is due to the careful growth sequences, i.e., the fibers are made first and the two matrix materials grown around them in sequence. Moreover, it can be grown in- situ, and in layers, particular shapes or as a massive volume. The overall physical design is that of a reaction separation process in which the reactant materials are released into the matrix where they are needed by hollow porous tubes. No external heat or mixing is required and no unused final product is present. Materials and energy are utilized most efficiently while generating a resultant material in which the form and microstructure can be controlled. The effluent from the first reaction supplies the reactant for the second reaction. It appears that, like bone, one material can form a template for the other. Thus the ability to control the smallest scale microstructure would be present. Physical testing showed that the composite thus produced had superior compressive strength and fails in a manner consistent with better modulus of elasticity and greater toughness than either the polymer or ceramic material alone. SEMs revealed the structure and mechanical and chemical bonding. It appears that templating of the ceramic into the polymer is occurring but further verification is needed. This would provide the superior type of microstructure control sought.

The function and performance of the self-diagnosis composites embedded in mortar/concrete blocks and concrete piles were investigated by bending tests and electrical resistance measurements. Carbon powder (CP) and carbon fiber (CF) were introduced in glass fiber reinforced plastics composites to obtain electrical conductivity. The CP composite has commonly good performances in various bending tests of block and pile specimens, comparing to the CF composite. The electrical resistance of the CP composite increases in a small strain to response remarkably micro-crack formation at about 200 (mu) strain and to detect well to smaller deformations before the crack formation. The CP composite possesses a continuous resistance change up to a large strain level near the final fracture of concrete structures reinforced by steel bars. The cyclic bending tests showed that the micro crack closed at unloading state was able to be evaluated from the measurement of residual resistance. It has been concluded that the self- diagnosis composite is fairly useful for the measurement of damage and fracture in concrete blocks and piles.

The electrically conductive fiber reinforced plastics (FRP) and ceramics matrix composites (CMC) have been designed and fabricated in order to introduce the self-diagnosis function which means the combination of reinforcement and damage diagnosis function into structural materials. The electrical conductivity was achieved by adding conductive fiber or particles into these composites. The composites with percolation structure consisting of carbon particles were found to have the advantages in response of conductivity to a small strain and in detectable strain range, comparing to the composites containing carbon fiber. A part of resistance change in the elongated composites with carbon particles remained after unloading despite its elastic deformation. The residual resistance increased with increasing applied maximum strain, showing that the composite possesses the function to memorize the previous maximum strain. The CMC materials containing TiN particles as a conductive phase indicated not only the fine response of resistance to slight deformation but also the increase in residual resistance during cyclic deformation at a constant load, suggesting that the composite have the ability to diagnose a cumulative damage through measurements of the residual resistance. These results suggest that the self-diagnosis functions peculiar to these composites are suitable for health monitoring techniques for many structural materials.

A displacement based finite element model in Fourier domain coupled with Multi-input-multi-output (MIMO) optimal feedback control algorithm, called Active Spectral Element Model (ASEM) is presented. Implementation of this model, in this paper, is focused on local control of broadband waves in composite 2D beam network. Point sensors for velocity feedback and Piezoelectric Fiber Composite (PFC) for distributed longitudinal and bending actuation are considered in this study. The proposed model can accommodate generic sensor- actuator configuration in collocated as well as non-collocated form with PID feedback scheme. The formulation takes into account both sensor and actuator dynamics and nearfield effect on the sensors. Under this proposed framework of ASEM, the main objectives are (1) design of optimal feedback control parameters for multiple sensor-actuator configuration from distributed structural performance viewpoint and (2) capture various complex features of actively controlled broadband wave transmission in a simulation based realistic approach. The admissible sensor-actuator locations and connectivities are identified based on a semi-automated strategy by computing the total change in squared amplitude spectrum. A frequency weighted variable feedback gain optimization algorithm is constructed by minimizing complex power flow. Also, an adaptive gain selection scheme with upper bound to the actuator input voltage in implemented. The proposed model is computationally much faster and smaller in size compared to conventional MIMO state space models. Case studies on a composite cantilever beam and a three member network are carried out to illustrate the efficiency of the model.

Development of new active composites using conventional structural materials are described in this paper. An active CFRP/Al laminate was proposed and developed, which became flat when it was kept at its hot pressing temperature 393K by electric resistance heating of the carbon fiber in the CFRP layer, and its curvature increased when it was air-cooled. The mechanism of its actuation is fundamentally the same as that of bimetal, but its major advantage is its directional actuation due to directionality of the reinforcement fiber and its anisotropy of CTE. FRM based active material was also developed. SiC fiber reinforced aluminum composite was laminated with unreinforced aluminum plate by the interphase forming/bonding method using copper insert foil. Curvature of the material monotonically changed as a function of temperature. It was also clarified that the copper concentrated around the SiC fiber which was introduced by the interphase forming/bonding method contributed to curvature increase of the actuator. In order to detect its deformation, pre-notched optical fiber was embedded in the active material and successfully broken in it to form an optical loss type sensor. Using this sensor, a simple relation between curvature change and change of optical loss to be used for its shape control was successfully obtained.

In this study, elemental ideas were proposed and demonstrated to realize a couple of smart material systems without using sophisticated and expensive sensors as follows: (1) Commercially available quartz type optical fiber was successfully embedded in aluminum matrix by the interphase forming/bonding method to be used as a sensor. (2) In order to obtain an interference type fiber optic strain sensor in matrix materials without using commercially available expensive one, a unique method was proposed, that is, a pre- notched optical fiber filament was embedded in epoxy resin matrix and was fractured apart in it to form a fiber optic strain sensor. (3) A simple and low cost sensor to detect temperature and strain of aluminum and its composite was proposed and demonstrated, that is, an oxidized nickel wire was embedded in aluminum matrix to form a temperature and strain sensor.

Three types of magnetic field operated shape memory ceramics have been developed. Namely, the shape memory movements can be operated by changes in magnetic flux density. The reversible shape memory effects are often induced by magnetostriction and magnetic field induced twin formation for Fe-Pd alloys. The former shows the precise shape change, whereas the later shows the large shape change expected. The strain value was about 182 ppm at 0.3 kOe at room temperature. The high magnetostrictive susceptibility was detected at low magnetic field. It was higher than that of Tb_0.3Dy_0.7Fe₂ thin film developed. The other magnetic field operated shape change is recently found on softening near critical temperature of superconductors. The softening induced shape memory effect (SSME) has been found from 9.5 K to 20 K in pure metallic niobium.

Detwinning in crystalline solids is a unique deformation mechanism partially responsible for the shape memory effect in addition to phase transformation. Owing to an insignificant dislocation process during detwinning leading to inelastic deformation, the residual strain can be recovered through a reverse transformation. The maximum shape recovery strain is intrinsically related to the lattice geometry and twinning mode. While the magnitude of shape recovery strain is related to a competition of detwinning versus dislocation generation responsible for the macroscopically observed martensite deformation. The detwinning magnitude is directional, and in the polycrystalline materials, it is related to the textures. Without textures, the detwinning process in polycrystalline solid is isotropic. With textures, the detwinning process is enhanced for certain directions and reduced for other directions and so do the shape recovery strain. The anisotropy in detwinning process allows the possibility of maximizing the potential of the polycrystalline shape memory alloys. This paper presents recent results on the anisotropy of detwinning as a function of loading mode and texture orientation. The anisotropy in detwinning process is also responsible for the direction-dependence of the shape recovery strain. The fundamental reason responsible for this detwinning anisotropy is associated with the combination of twinning types, texture orientation and loading direction, which can be further treated mathematically based on a physical model.

Due to special material properties, shape memory alloys (SMA) are finding increasing attention in micro system technology. However, only a few processes are available for the machining of miniaturized SMA-components. In this connection, laser material processing offers completely new possibilities. This paper describes the actual status of two projects that are being carried out to qualify new methods to machine SMA components by means of laser radiation. Within one project, the laser material ablation process of miniaturized SMA- components using ultra-short laser pulses (pulse duration: approx. 200 fs) in comparison to conventional laser material ablation is being investigated. Especially for SMA micro- sensors and actuators, it is important to minimize the heat affected zone (HAZ) to maintain the special mechanical properties. Light-microscopic investigations of the grain texture of SMA devices processed with ultra-short laser pulses show that the HAZ can be neglected. Presently, the main goal of the project is to qualify this new processing technique for the micro-structuring of complex SMA micro devices with high precision. Within a second project, investigations are being carried out to realize the induction of the two-way memory effect (TWME) into SMA components using laser radiation. By precisely heating SMA components with laser radiation, local tensions remain near the component surface. In connection with the shape memory effect, these tensions can be used to make the components execute complicated movements. Compared to conventional training methods to induce the TWME, this procedure is faster and easier. Furthermore, higher numbers of thermal cycling are expected because of the low dislocation density in the main part of the component.

Shape Memory Alloy (SMA) wire technology was used as primary flight control actuators on a 99-inch wingspan remote controlled aircraft. Modifications were made to a Dynaflite Butterfly and its Futaba remote control system. Comparisons were recorded between the original Futaba electric motor servo system and the SMA actuator system in terms of input power requirement, response time, actuation geometry, output power, and proportional control characteristics. The advantages and limitations of this application of SMA technology were exposed. This project shed light on further possibilities for use of SMA technology that could eliminate much of the weight, complexity, and cost associated with current use of remote actuation and linkage systems. It is the author's hope that the information presented herein will help facilitate further development of SMA in highly critical miniature applications.

In this paper, we present a way to fabricate microgripper that could well meet the industry needs, i.e. low cost, high performance etc. A medium sized microgripper of 1.6 mm in length has been fabricated, tested and simulated. This novel design, with its fabrication process, makes it possible for batch production, which results in lower production cost. Its low cost has unique advantages in both medical and manufacturing industries. For example, in the medical field, the microgripper could be disposed after every use, much like a syringe without imposing excessive costs. Our finite element simulation agrees reasonably well with the measured behavior.

An important property of shape memory (SMA) wires is the generation of high stresses when the strain recovery is impeded during heating. These stresses are called recovery stresses and can reach stress levels up to 800 MPa. In a first step this paper compares and discusses the recovery stress generation and mechanism in different SMA-wires based on experimental results. All experiments were performed on a specially equipped thermomechanical testing apparatus. Complex stress-, strain-, and temperature profiles can be programmed to study the thermomechanical behavior of a SMA. The knowledge of these recovery stresses was applied for composite materials. Embedding pre-strained SMA-wires in a composite result in a material with adaptive properties that are related to the reversible martensitic transformation in the SMA-wires. The behavior of the SMA-composites was studied in three ways. Starting from the experimental results on SMA-wires and the knowledge of composite materials, the behavior of the SMA- composites was predicted. A computer simulation model has been used for the same purpose. Thirdly, thermomechanical experiments were performed on the SMA-composites. The theoretically calculated and the simulated results were validated by comparison with these experimental results. In conclusion, links were established between the recovery stress behavior of a SMA-wire and the thermomechanical behavior of SMA-composites. This knowledge can be used to accurately design SMA-composites based on material data of individual SMA-wires.

It is well known that composites, although strong and lightweight, can suffer badly when impacted. This can have catastrophic consequences to a structure. By embedding superelastic shape memory alloys into a composite structure, it is possible to reduce impact damage quite significantly. Superelastic shape memory alloy (SMA) wires absorb a lot of the energy during the impact due to their 'elastic' and hysteretic behavior. The mechanism behind superelasticity is the reversible stress induced transformation from austenite to martensite. If a stress is applied to the alloy in the austenitic state, large deformation strains can be obtained and stress induced martensite is formed. Upon removal of the stress, the martensite reverts to its austenitic parent phase and recoverable strains of up to 8% can be achieved. This paper will report on the results, in which superelastic shape memory alloys were pre-strained to 1.5% and 3% and then embedded into glass fiber/epoxy composite plates. These plates were then impact tested. The effect of embedding wires at different depths of the specimen, different types of wires (martensitic NiTi and stainless steel) and also different volume fractions of wires was also investigated. The results of the impact tests were examined by ultrasonic C-scan to determine the size of the delamination area. The energy absorbed and the maximum impact force were also determined.

This paper describes the potential of a smart monitoring system, incorporating optical fiber sensing techniques, to provide important structural information to designers and users alike. This technology has application in all areas including aerospace, civil, maritime and automotive engineering. In order to demonstrate the capability of the sensing system it has been installed in a 35 m free-standing carbon fiber yacht mast, where a complete optical network of strain and temperature sensors were embedded into a composite mast and boom during lay-up. The system was able to monitor the behavior of the composite rig through a range of handling conditions and the resulting strain information could be used by engineers to improve the structural design process. The optical strain sensor system comprises of three main components: the sensor network, the opto-electronic data acquisition unit (OFSSS) and the external PC which acts as a data log and display. Embedded fiber optic sensors have wide ranging application for structural load monitoring. Due to their small size, optical fiber sensors can be readily embedded into composite materials. Other advantages include their immediate multiplexing capability and immunity to electromagnetic interference. The capability of this system has been demonstrated within the maritime environment, but can be adapted for any application.

Spacecraft inhabit an environment, which presents many hazards to their structural integrity and continued operation, and are intrinsically expensive to repair. Naturally-occurring micrometeoroids and debris from previous missions can both produce significant impact damage, particularly in advanced materials such as carbon-fiber-reinforced plastic (CFRP). A sensor capable of recording impact events, and measuring the extent of the damage caused, would therefore be a useful tool in minimizing the risks and cost of spacecraft operation. This paper considers the use of multiplexed optical fiber Bragg grating based sensors for use in this application. It is envisaged that sensors should be used to optimize replacement schedules and prevent service failure. The interrogation systems have been developed as collaborative research between the Optoelectronics Research Centre and the Department of Engineering Materials at the University of Southampton, also involving a number of external collaborators (including ESA, and, in the UK, the following: DERA, Sensor Dynamics, NERC, and DTI). We utilize superluminescent erbium doped fibers as the light source and an acousto-optic-tuneable filter (AOTF) as the wavelength-selective element. Our latest developments in interrogation technology result in the creation of a high speed, high-resolution multiplexed sensor. This technology shows promise for assessing impact damage caused by low, high and hypervelocity impacts. The potential for counting and characterization of impinging particles from strain sensor readings (both transient and residual) is discussed.

The aim of the present paper is to describe the tests performed on the zinc-aluminum specimens cast with optical fibers inserted in it. Aspect concerning the wettability of the fiber matrix interface and the buoyancy of the fiber into the melt are considered. Special care has been devoted to the realization of the chill for obtaining a slender specimen suitable for vibration tests. Metallographic studies have been carried out in order to obtain information on the state of the optical fiber. One arm of a Mach-Zehnder interferometer has been set with the specimen described above. Optimal correlation has been found between the excitation applied on the specimen and the response obtained by the fringe pattern variation.

Re-entry in planetary atmospheres is one of the most challenging environments to be faced by an aerospace structure. Presently space agencies are studying and developing programs to reduce launch costs by developing a new generation reusable launch vehicles. In fact a significant portion of the launch cost, for those vehicles, is represented by maintenance, non destructive testing and personnel involved in ground operations. For instance NASA and Lockeed Martin are leading the VentureStar program, where the real time health monitoring is considered an important aspect, while ESA has now finished a preliminary analysis for different reusable launch vehicle configurations. Fiber optic sensors which can be embedded into structural components can provide an efficient means for fast and reliable structural health monitoring. In this paper the possibility of embedding fiber optic sensors into materials subjected to particularly critical thermal treatments is verified. Several specimens of metal alloys and carbide based powders with embedded optical fibers have been prepared by the high pressure high velocity oxy fuel technique. The tests have proven the feasibility of the embedding with the above mentioned technology which exposes the fibers to quite a severe environment during the deposition. Micrographic analysis and optical transmission tests have been carried out on the sprayed specimens.

Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. So there was a need to develop an inherent biomaterial, a self-repairing material which can remediate the cracks and fissures in concrete. Bacterial concrete is a material, which can successfully remediate cracks in concrete. This technique is highly desirable because the mineral precipitation induced as a result of microbial activities is pollution free and natural. As the cell wall of bacteria is anionic, metal accumulation (calcite) on the surface of the wall is substantial, thus the entire cell becomes crystalline and they eventually plug the pores and cracks in concrete. This paper discusses the plugging of artificially cracked cement mortar using Bacillus Pasteurii and Sporosarcina bacteria combined with sand as a filling material in artificially made cuts in cement mortar which was cured in urea and CaCl₂ medium. The effect on the compressive strength and stiffness of the cement mortar cubes due to the mixing of bacteria is also discussed in this paper. It was found that use of bacteria improves the stiffness and compressive strength of concrete. Scanning electron microscope (SEM) is used to document the role of bacteria in microbiologically induced mineral precipitation. Rod like impressions were found on the face of calcite crystals indicating the presence of bacteria in those places. Energy- dispersive X-ray (EDX) spectra of the microbial precipitation on the surface of the crack indicated the abundance of calcium and the precipitation was inferred to be calcite (CaCO₃).

The two-dimensional control of cell adhesion is desired for a number of cell- and tissue culture applications. Thus, a suitable method for the two-dimensional control over surface chemistry, which leads to the display of cell-adhesive and non-adhesive signals is required. In our study, allylamine plasma polymer (ALAPP) deposition has been used to provide a cell-adhesive substrate, while additional grafting of poly(ethylene oxide) (PEO) on ALAPP surfaces has been used to prevent cell adhesion. Two-dimensional control over the surface chemistry was achieved using excimer laser ablation. Ablation experiments were carried out using a 248 nm excimer laser with energy densities of 17 - 1181 mJ/cm² and 1 - 16 pulses per area. Results obtained by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) show controlled thickness ablation of the plasma polymer and the additional PEO graft polymer. Cell culture experiments using bovine corneal epithelial cells show that two-dimensional control of cell adhesion can be achieved by using appropriate masks in the laser beam.

During the past 20 years or so, various conjugated polymers have been synthesized with unusual electrical, magnetic, and optical properties owing to the substantial (pi) -electron delocalization along their backbones. Having a conjugated all- carbon structure with unique molecular symmetries, carbon nanotubes have recently been shown to also possess interesting optoelectronic properties. These properties allow conjugated polymers and carbon nanotubes for many potential applications. However, the often need to be aligned or patterned in certain manners for an effective incorporation into devices. In this paper, we summarize our recent work on the use of plasma techniques for generation and microfabrication of conjugated polymers and aligned carbon nanotubes.

We propose a novel method to design the shape of small elastic robots made entirely of electroactive polymer (EAP) gel. The gel operates as actuators in microsystems and can facilitate bending motions. In this paper, we bring out directional deformation from originally bending type polymer driven by electric fields. The key idea is to partially reduce the structural flexibility through shape design. To achieve directional motion, we designed gels with wave-shaped surfaces. The thick parts and thin parts of the surface are distributed in either one or two directions. We developed a mollusk type gel robot which shows bi-directional motion. In this way, we propose the method to design the desired deformation response by shape design of the material in advance. This technique is especially suited for MEMS consisting of soft materials.

This paper first presents a state of the art on electroactive polymer sensors and actuators and some experimental data pertaining to them. The paper then discusses the current state of the art in MEMS technologies in connection with robotic micro-manipulation and assembly as well as sensing and actuation. The paper then discusses the potential applications of electroactive polymer sensors and actuators to micro- electromechanical systems (MEMS) technologies such as microgripper and microsensor, microactuator arrays and microsensor arrays, micropumps, and micro-robots with sensing and actuation capability. It further discusses a number of potential industrial as well as biotechnological and medical applications requiring MEMS technologies that can benefit from the advances made in recent years in electroactive polymer sensors and actuators. The paper in particular presents modeling, design, fabrication and testing of a number of micromanipulators and multi-fingered robotic hands.

The authors propose a new optically-driven actuator system which utilizes 'photo-induced phase-transition' (PIPT) phenomena. This system is expected to be useful for micromechanical systems, since it provides wireless energy supply by light. The concept and the material properties are reported. PIPT phenomena have been recently reported to occur in various materials. These materials show bi-stability on their material phase such as structure, optical properties, magnetic properties, etc. The phase of the material is changed by irradiation of light with fixed wavelength, as well as by temperature or external fields. In this report, a kind of polydiacetylene (PDA) substituted with alkyl-urethane is investigated. This material is known to show reversible PIPT around 125 degrees Celsius between 'blue' phase and 'red' phase. The authors measured the induced macroscopic elongation of PDA crystal using a laser-focus displacement meter. For the first step, the phase of the sample was controlled by thermal phase-transition hysteresis. The induced strains due to the phase transition were measured to be highly anisotropic: 2%, 0.03%, and 0.9% at 125 degrees Celsius for a-, b-, and c-axes, respectively. These values are larger than that of piezoelectric or thermal-expansion materials that are conventionally used for microactuators. Thus this material is expected to be used for mechanical actuators, which are driven not only thermally, but also optically.

The mechanisms of actuation operating in polymeric actuators are reviewed along with a comparison of actuator performance. Polymer hydrogel actuators show very large dimensional changes, but relatively low response times. The mechanism of actuation involves several processes including electro-osmosis and electrochemical effects. Conducting polymer actuators operate by Faradaic reactions causing oxidation and reduction of the polymer backbone. Associated ion movements produce dimensional changes of typically up to 3%. The maximum stress achieved to date from conducting polymers is not more than 10 MPA. Carbon nanotubes have recently been demonstrated as new actuator materials. The nanotubes undergo useful dimensional changes (approximately 1%) but have the capacity to respond very rapidly (kHz) and generate giant stresses (600 MPa). The advantages of nanotube actuators stem from their exceptional mechanical properties and the non-Faradaic actuation mechanism.

Influence of LPCVD deposition condition, substrate, film thickness, crystallized degree and pre-annealing on residual stress in LPCVD polysilicon films was studied. The polysilicon deposited on PSG substrate shows the lowest residual stress. The relationship between crystallized degree of polysilicon films and the film thickness was investigated with the aid of Raman Scattering Spectrum. The residual stress shows a significant dependence on the film thickness because crystallized degree raises with the film thickness increase. The test results show that (1) for a thinner film (0.20 micrometer), even if to use a higher deposition temperature (630 degrees Celsius), its crystallized degree is still quite low and a quite higher residual tensile stress is resulted in the film. (2) for a thick film (4 micrometer), even if to use a lower deposition temperature (580 degrees Celsius), a significant crystallization still will occur in as-deposited films and a residual tensile stress is resulted in the films. A pre-annealing step before polysilicon boron doping is brought into the fabrication process of multi-layer diaphragm structure. It can be used as a method to control stress in highly doped polysilicon films. The stress control test of highly boron doped polysilicon/oxide diaphragm structure was carried out. The result shows that the property and magnitude of the stresses in highly boron doped polysilicon-oxide diaphragm can be arbitrarily changed in certain range by varying the holding time of final annealing.

Synthetic opal has been used as a template for making 3D inverse opals of silica, titania and silicone rubber. The materials are mesoporous with connected pores and channels and have better opalescence than the opal templates they replace. Thin films of synthetic opal have been grown onto glass substrates by spin coating and these have also been used as templates for making thin films of inverse opal and as masks for depositing metal nanodots. This method produced hexagonally patterned 50 nm gold dots on a flat graphite substrate.

Protein patterns were printed using conventional microlithographic materials in a bilayer arrangement and unconventional exposure tools. The bilayer resist stack consists of a bottom Poly(tertButylMethAcrylate) layer and a top DNQ-novolak layer. The protein features were printed in 'step & repeat' mode, that is a flow-cell, 'real-time' process, as follows: (1) the exposure step is carried out by the focused beam of a confocal microscope tuned to 488 nm wavelength; (2) the development step is performed flowing the photoresist developer through the cell; (3) the selective deposition of the protein (a green fluorescent protein, FITC avidin for visualization) is achieved via the flow of the protein solution through the cell until a desired contrast has been reached; (4) the control step consists of an on-line monitoring of the red fluorescence for the control of the development of the top layer, and of the green fluorescence for the control of the protein patterning. respectively. The techniques have of a seamless portability in a biomedical environment, and for 'step & repeat' protein patterning the advantage of a high and controllable resolution. The process can be applied for the in-house fabrication of model biomolecular and cellular devices. Examples for the patterning of neuronal cells are also given.

Structures have been electroplated directly to metal (Al) pads on Si wafers using only the metal pad geometry to define the position and shape of the electroplated pad. No further processing steps are required after the electroplating. These pads have been used to form the sensing elements in an adhesive bond degradation sensor. Other uses could include the electroplating of high density materials to increase inertial/accelerometer sensor mass for higher sensitivity. The electroplating has been performed on Al pads formed in a CMOS compatible process on whole Si wafers. Multiple 'bus bars' connected to different sensor pads have been used to simultaneously electroplate structures with different heights. Both zincating and evaporation of a Cu seed layer on the Si substrate followed by electroplating have been investigated to determine the parameters to achieve optimum Cu cover and the best adhesion of the electroplated Cu to the Al/wafer. This involved the development of a test to measure the adhesion of 100 micrometer X 100 micrometer electroplated Cu studs on a silicon wafer.

Resonant mode micromechanical devices have great potentials due to their high sensitivity and easy signal processing. As they are also sensitive to environmental effects, vacuum packaging is often required, which largely increases the costs. The current study focuses on such environment induced reliability problems and degradation processes. Stiffening effect was observed on thin silicon nitride and silicon carbide cantilever beams in air. The resonance frequency gradually increases in time. When the cantilever is subjected to mechanical shock or large deflection, the resonance frequency suddenly drops, and then increases again. Air, increased humidity, argon rich and nitrogen rich atmosphere influence the stiffening and the shock response behavior. The effects are explained with the surface oxidation model. The oxide layer introduces stress in the structure increasing the overall stiffness, while mechanical shocks crack the layer. Silicon resonators gather airborne particles from the atmosphere due to electrostatic charging. The extra mass results in decrease of the resonant frequency. All these processes lead to unstable resonance frequency and thus to failure of the resonant mode device. Tests in inert environment suggest cheap atmospheric packaging solution to obtain reliable operation and yet good performance.

A new technique has been developed to probe the surface microtopography an the viscoelastic properties with the nanometric resolution using the vibrating modes of Scanning Probe Microscopy. Weak cantilevers, although having good force sensitivity, have found limited use for investigating of material's nanomechanical properties by conventional force modulation and intermittent contact atomic force microscopy. This is due to low forces and indentations that these cantilevers are able to exert on the surface and high amplitudes needed to overcome adhesion to the surface. Here it is shown that by employing electrostatic forcing of cantilever the imaging of local elastic properties of surface and subsurface layers can be carried out. Also, by mechanically exciting the higher vibration modes in contact or intermittent contact with the surface and monitoring the phase of vibrations, the contrast due to local surface elasticity together with surface microtopography is obtained.

Neodymium oxide nanoparticles/TiO₂/ORMOSIL composite sol- gel thin films have been prepared by combining an inverse microemulsion technique and the sol-gel technique at low temperature. Transmission electron microscopy and scanning electron microscopy have been used to characterize the size and structural properties of the neodymium oxide nanoparticles and composite thin films. Photoluminescence and up-conversion emission properties of these composite thin films deposited on silicon substrates have been studied. A relatively strong room-temperature photoluminescence emission at 1064 nm corresponding to the ⁴F_3/2 yields ⁴I_11/2 transitions from these composite thin films has been observed as a function of the heat treatment temperature. An intense up-conversion emission in violet (402 nm corresponding to ⁴D_3/2 yields ⁴I_13/2 transitions) color from the composite thin films baked at different temperatures upon excitation with a yellow light (587 nm) has been observed. In addition to this violet emission, an UV emission at 372 nm and a weak blue emission at 468 nm have been obtained. The mechanism of the up-conversion emission has been explained by means of an energy level diagram. The lifetimes of the violet emissions have been measured.

Fe-Pd thin films were deposited on SiO₂/Si substrates by RF magnetron sputtering. The compositions were determined by the chemical analysis to be ranged in Pd-content about 30.0 at%. The thin films were solution-treated at 1173 K for 180s in vacuum and subsequently cooled by Ar gas flow. In the Fe- 32.62 at%Pd specimens, the as-deposited thin film possesses ultra-fine grains resulting in a long-range disorder structure. After the heat treatment, ((gamma) Fe, Pd) with an fcc structure is recrystallized and the crystallized thin film shows the texture orientation with (111) and (100) planes parallel to the film surface. In the Fe-29.97 at%Pd specimens, the as-deposited thin film exhibits a bcc structure due to less Pd content. After the heat treatment, ((gamma) Fe, Pd) fcc structure is formed at higher Pd content. Magnetic properties of the thin films are affected by the composition, crystal structure and grain size. In as-deposited thin films, two- stage I-H hysteresis loops are observed on account of the fine grains. After the heat treatment the rectangularity of the hysteresis loops is improved especially in the oriented Fe- 32.62 at%Pd thin film and Curie temperature increases with the increase of Pd-content. Magnetostriction of 3.6 X 10^-5 at an applied magnetic field H equals 8.0 kA/m (equals 0.1 kOe) is observed in the solution-treated Fe-32.62 at%Pd thin film.

We have successfully developed the computer simulation technique of modeling and design for continuous conductive structures in the self-diagnosis composite. The Monte Carlo (MC) method has been used for the simulations of the microstructures at the array of two or three dimensional lattices. The simulation results were analyzed and discussed in relation to microstructural parameters such as particle size, content, aspect ratio, etc. The computer simulation gave us important and quantitative information to obtain continuous structure of the particles dispersed in a matrix phase.

The hydrogenated nanocrystalline silicon (nc-Si:H) films have attracted an extensive attention for their novel structure and peculiar properties. The nc-Si:H films are prepared by the high purity hydrogen highly diluted silane as the reactive gases which are activated at r.f. and d.c. double power sources, in a conventional plasma enhanced chemical vapor deposition (PECVD) system. The film samples have been studied by high-resolution electron microscopy (HREM), Raman scattering spectroscopy. Based on the dynamics analysis of the fabrication process of the nc-Si:H films, a fractal growth model which is called diffusion and reaction limited aggregation (DRLA) model was proposed. It is shown that the results of the computer simulation agree with the experimental results.

Polycrystalline thin films of Mg-modified lead titanate (PMT) were deposited on Pt/SiO₂/Si substrates using a diol-based sol-gel process. 1,3-propanediol was used as solvent to minimize the number of cycles of spin coating and drying processes to obtain the desired thickness of high quality thin film. By changing the Mg content (2 to approximately 8 mol%) and heating temperature (500 to approximately 800 degrees Celsius), the influences of various processing parameters on the characteristics of thin films were studied. With the increase of the Mg content, the relative dielectric constant ((epsilon) _r) of PMT thin film increased from 39 to 91 at the heating temperature of 700 degrees Celsius. It was found that the coercive field (Ec) and the remanent polarization (Pr) decreased, but the pyroelectric coefficient (gamma) increased with an increase of Mg content. The results reveal that PMT thin film with a Mg content of 6 mol% exhibits the largest figures of merit for the voltage responsivity and the specific detectivity at a heating temperature of 700 degrees Celsius.

High-performance pyroelectric infrared (IR) detectors have been fabricated without the back side etching process using Mg-modified lead titanate (Pb_1-xMg_xTiO₃) thin films. PMT thin films were deposited on (111)-oriented Pt thin film on SiO₂/Si(100) substrates by a diol-based sol-gel process. The randomly oriented PMT thin film exhibits a relatively small dielectric constant and a large pyroelectric coefficient without poling treatment. The pyroelectric characteristics of point detector with various Mg contents as a function of modulation frequency are compared. It was found that the PMT(6) thin film detector has a large voltage responsivity of 5280 (V/W) at 20 Hz. The specific detectivity (D*) at 100 Hz is 5.12 X 10⁷ cmHz^1/2/W. The results showed that Pb_1-xMg_xTiO₃ thin film with x equals 0.06 [PMT(6)] was most suitable for use as a pyroelectric IR detector.

The change in strength of barium titanate/zirconia composite on polarization treatment is evaluated, and the mechanism of this phenomenon is discussed. We have already reported that the bending strength of this composite has increased on longitudinal poling. In this study bending strength of BT/8YSZ composite increased on longitudinal poling and decreases on transverse poling compared with the untreated samples. Both strengthened and weakened specimens tend to return to the almost original strength by heating over Tc of barium titanate. Then, the crack propagation after polarization treatment is observed by SEM, and the detour of cracks around barium titanate grains is found in the cracks going along the poling direction. The detour of crack probably has close connection with the increase in strength in the poling direction.

C-axis oriented aluminum nitride (AlN) films were deposited on SiO₂ coated Si substrates by reactive rf magnetron sputtering. Growth behaviors of the AlN films deposited at various deposition conditions such as rf power, sputtering pressure, nitrogen concentration and substrate temperature were investigated. Highly c-axis oriented AlN films were identified at substrate temperatures as low as 250 degrees Celsius. A densely pebble-like surface texture of c-axis oriented AlN films with an average grain size of about 100 nm was observed by scanning electron microscopy (SEM). The surface acoustic wave (SAW) characteristics with an interdigital transducer/AlN/SiO₂/Si structure were studied. The phase velocity and the insertion loss measured by a network analyzer were 6080 m/sec and -24.8 dB, respectively.

In this work, a negative-tone photoresist, SU8, used in UV- based micromachining of high-aspect-ratio MEMS has been tested using proximity X-ray printing. Very thick (a few hundreds of micrometers) SU8 resist layers were processed with standard cleanroom equipment and exposed with 1 - 10 keV X-rays at a beamline of the CAMD synchrotron radiation facility. It showed a large increase in sensitivity in deep X-ray lithography compared to the standard poly(methyl-methacrylate) (PMMA) resist, resulting in increased throughput potential. Resist microstructures with aspect-ratio as high as 50 (height 350 : width 7) and vertical sidewalls, were produced. The benefits of using such X-ray resist in X-ray manufacturing are discussed.

Boride material is said as the useful material, which has high melting point and high strength. B₄C in carbide is very hard at the next of the diamond and cubic-BN in the Mohs hardness and B₄C has excellent chemical stability and high strength. B₄C is being used as the polishing material from the hardness. However, it is difficult to make sintered body from high melting point (2623 K). Several silicon boride phases such as SiB₄, SiB₆, SiB_6-x, SiB_6+x, and Si₁₁B₃₁, were previously reported. Silicon hexaboride (SiB₆) has proved to be a potentially useful material because of its high degree of hardness, moderate melting point (2123 K), and low specific gravity. We studied the preparation of SiB₆-B₄C-SiC sintered body in this report. We knew experientially that SiB₆ reacts with carbon at the high temperature, and forms B₄C or SiC. Carbon addition SiB₆ sintered body produced by hot pressing and reaction sintering that sintering condition was 1973 K for 3.6 ks in vacuum under a pressure of 25 MPa. The relative density of sintered bodies (SiB₆-0,5,10,15 wt%C) was approximately 100%. Characterization of mechanical properties was used indentation, Vickers hardness and thermal

Lead lanthanum zirconate titanate (PLZT) powders were prepared by three different sol-gel methods. In one process, the precursor materials used were lead hydroxide, lanthanum nitrate hexahydrate, zirconium tetra-n-butoxide, and titanium tetraisopropoxide along with 2-methoxyethanol as a solvent. An amount of distilled water equivalent to the total molar concentration of Pb, Ti, and Zr was added to the above solution. In a second process, the precursor materials used were lead acetate, lanthanum nitrate hexahydrate, zirconium tetra-n-butoxide, and titanium tetraisopropoxide along with 2- methoxyethanol as a solvent. An amount of distilled water equivalent to the total molar concentration of Pb, Ti, and Zr was added to the above solution. In a third process, the precursor materials used were lead acetate, lanthanum nitrate hexahydrate, zirconyl nitrate, and titanium tetra-n-butoxide. Distilled water and acetic acid were used as solvents. Triethyleneglycol or diethanolamine was used in each of the above processes as a chemical additive to modify the hydrolysis and condensation of the solution. Thermal gravimetric-differential thermal analysis was used to study the weight changes of the dried gels as a function of annealing temperature. Dried samples were heated for 1 h in the range of 673 to 1073 K in air atmosphere. The crystalline phases of calcined PLZT powders were identified by X-ray diffraction analysis. The calcined powder was pressed by CIP at 100 MPa. The samples were sintered at 1173 K, 1273 K, and 1323 K and their relative dielectric constants were measured.

In this study, SiB₆-0 at approximately 20 wt%C composites were investigated relationship between microstructure and electrical conductivity prepared by hot pressing. The samples were sintered at 1973 K for 3.6 ks in vacuum under a pressure of 25 MPa. The relative density of sintered body was measured by Archimedes' method. The relative density of SiB₆-0, 5,