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We report a technique for fabricating three-dimensional structures from two-dimensional photomasks in a single exposure. Size-dependent transmission properties of apertures in the photomask and exposure energy were used to control polymer feature dimensions. The photomasks were produced by electron beam lithography, and apertures in the photomasks were 0.35–5.5 pm wide and 20–30 μm long. Photomasks were coated with the negative tone photoresist SU-8, and following exposure and postexposure processing, the resulting SU-8 features had widths from 0.35 to 5.5 μm and heights from 1.1 to 10.8 μm. With this technique, nanoscale features were easily coupled to microscale features because they were created in the same photoresist layer with one exposure. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the laser-induced ablation of bovine bone assisted by a transparent liquid layer on top of the target surface. A Q-switched Nd:YAG laser was used to ablate bovine tibia at various energy levels. Distilled water was applied to the sample surface in order to examine the role of a transparent liquid layer during the ablation. Plasma generation and transient acoustic waves were monitored to identify dominant mechanisms involved in the ablation process. Ablation efficiency was measured from the cross-sectional tomography acquired by optical coherence tomography (OCT). Ablation with a liquid layer lowered the damage threshold and enhanced both the laser-induced acoustic excitation and the ablation efficiency, which saturated at higher radiant exposures. The enhanced ablation of the liquid-assisted process is primarily due to photomechanical effects associated with explosive vaporization and plasma confinement. The saturation of the pressure amplitude and ablation efficiency was attributed to increased plasma shielding. [ABSTRACT FROM AUTHOR]

Digital image correlation is an appealing technique for studying crack propagation in brittle materials such as ceramics. A case study is discussed where the crack geometry, and the crack opening displacement are evaluated from image correlation by following two different measurement and identification routes. The displacement uncertainty can reach the nanometer range even though optical pictures are dealt with. The stress intensity factor is estimated with a 7% uncertainty in a complex loading set-up without having to resort to a numerical modelling of the experiment. [ABSTRACT FROM AUTHOR]

Abstract: We developed a method to microfabricate flexible electrode arrays on a thin Kapton substrate, which was engineered to minimize trauma when inserted between the dura and skull to obtain surface EEG recordings. The array consisted of 64 gold electrodes, each 150μm in diameter on a 750μm spaced 8×8 grid. Using photolithographic procedures, any arrangement of electrodes can be implemented. We used the electrode array to record evoked response signals to create topographical maps of the whisker barrels on the cortical surface with excellent signal stability over a period of 8h. The materials used for this fabrication are potentially biologically inert and, with some additional modifications to the design, can be chronically implanted with minimal side effects. Retinal prosthesis, human neurosurgery, and neurological research are all limited to some degree by the resolution and biological compatibility of the implants used. This type of array could greatly enhance the spatial resolution, signal quality, and stability of implantable surface electrode arrays. [Copyright &y& Elsevier]

Abstract: The critical dimension (CD) of wafers in photolithography is the most important parameter that determines the final performance of devices. The sampling of CD’s, as a result, is essential and must be taken with caution. Process yield is a common criterion used in the manufacturing industry for measuring process performance. A measurement index, called S pk, has been proposed to calculate the yield for normal processes, and can be used to establish the relationship between the manufacturing specifications and the actual process performance, which provides an exact measure on process yield. In this paper, we solve the CD control problem based on the yield index S pk. The critical values required for the hypothesis testing, using the standard simulation technique, for various commonly used performance requirements, are obtained. Extensive simulation results are provided and analyzed. The results indicate that a sample size greater than 145 is sufficient to ensure that the decisions made are insensitive to the process precision and the process accuracy. The investigation is useful to the practitioners for making reliable decisions in testing process performance of a stepper and quality of an engineering lot by CD control. [Copyright &y& Elsevier]

In this paper, both photoelasticity and moiré interferometry were successively incorporated with finite element method to investigate the predicted thermal stresses and lateral displacement of bonded structures calculated from different theories. It was found that the distributions of moment and transverse force play significant roles in making different values of thermal stresses in the adherends by authors’ and Suhir's 1986 theories. On the other hand, the values of lateral displacement obtained from different theories are almost identical. [ABSTRACT FROM AUTHOR]

Abstract: Due to the light source limitation and prohibitive cost inherent in conventional photolithography, various nontraditional patterning technologies, such as imprint lithography, electron beam or X-ray lithography have been attempted over the past 10 years. In this paper, a UV imprint lithography process is introduced for patterning sub-micrometer structures by using a soft PDMS mould, and an imprint experimental device with a loading mechanism driven by PZT for generating a time-variant load is described. As shown experimentally, an increased pressing load will reduce the thickness of the resist layer, leading to a reliable etching-through of the resist. It is found, however, that the mechanical pressing can generate geometrical distortion on the patterned resist mainly due to the elasticity. Incorporated with the use of a low viscosity photo-curable resist, a loading process with a load release step is proposed to reduce the geometrical distortion on the resist patterns. In the loading process, the loading force is partially released after the press peak but before the resist curing. Such a loading process can reduce the elastic distortion while attaining a thin remained resist layer. It is shown that this loading process, called Distortion Reduction by Load Release or DRLR simply can be combined with an imprint process for different patterning areas and feature sizes. [Copyright &y& Elsevier]

Abstract: This work presents the development of a method which analyzes metallic wear debris and contaminants found to be present in fuels used by Diesel engines. The particles have been isolated by following two complementary methods; firstly, a magnetic separation method and then a filtering method using membranes. Particles are subsequently characterized by means of optical and electron microscopy, where it is possible to establish the type and severity of the wear, as well as establishing how the mechanism parts are actually affected by wear. This technique allows a predictive maintenance of the fuel injection systems to be carried out, as it allows for possible breakdowns to be detected prior to a serious failure being produced. [Copyright &y& Elsevier]

Knowledge regarding the coronal magnetic field is important for the understanding of many phenomena, like flares and coronal mass ejections. Because of the low plasma beta in the solar corona, the coronal magnetic field is often assumed to be force-free and we use photospheric vector magnetograph data to extrapolate the magnetic field into the corona with the help of a nonlinear force-free optimization code. Unfortunately, the measurements of the photospheric magnetic field contain inconsistencies and noise. In particular, the transversal components (say B x and B y ) of current vector magnetographs have their uncertainties. Furthermore, the magnetic field in the photosphere is not necessarily force free and often not consistent with the assumption of a force-free field above the magnetogram. We develop a preprocessing procedure to drive the observed non–force-free data towards suitable boundary conditions for a force-free extrapolation. As a result, we get a data set which is as close as possible to the measured data and consistent with the force-free assumption. [ABSTRACT FROM AUTHOR]

We present a calculation model to investigate the focusing characteristics of an atomic beam in a laser standing wave, taking the wave nature of the atomic propagation into account. The effects of atom source, optical parameters of the laser field and the substrate position on atom focusing are analyzed. Numerical simulations indicate that the best focusing performance can be obtained by repositioning the substrate or optimizing the longitudinal atomic beam speed, laser intensity and the detuning of the laser beam. The feature width of the nanostructure is mainly determined by the transverse speed distribution of atoms. Some methods for optimizing experimental parameters are suggested. [ABSTRACT FROM AUTHOR]

We report that capillary flows in an evaporating thin film create line patterns, with widths ranging from a few micrometers to less than 100 nm. Deliberate patterning of such lines requires contact-line pinning and the presence of foaming surfactants. Large-scale photolithography can guide and control these structures by creating pinning points and steering evaporation. We provide demonstrations of this process by making self-assembling lines of colloidal quantum dots and microspheres. [ABSTRACT FROM AUTHOR]

In order to improve productivity in the photolithography process of high-product mix/low-volume factories, an automated stepper load balance allocation system was developed. The system enables us to maintain a balanced load distribution of tool constraint layers among all steppers. We developed a processing time estimation function and a load balance allocation function. The processing time estimation function calculates accurate loads based on the processing times related to the product, the process layer, and the stepper. The load balance allocation function was realized by applying a dynamic programming method. The system has decreased the deviation in the total processing time among all steppers by 10%, compared to the conventional manual allocation method. [ABSTRACT FROM AUTHOR]

The measured performance of a column-type microthermoelectric cooler, fabricated using vapor-deposited thermoelectric films and patterned using photolithography processes, is reported. The columns, made of p-type Sb2Te3 and n-type Bi2Te3 with an average thickness of 4.5 pm, are connected Using Cr/Au/Ti/Pt layers at the hot junctions, and Cr/Au layers at the cold junctions. The measured Seebeck coefficient and electrical resistivity of the thermoelectric films, which were deposited with a substrate temperature of 130 °C, are -74 μV/K and 3.6 × 10-5 - m (n-type, power factor of 0.15 mW/K² - m), and 97 μV/K and 3.1 × 1o-5 Ω - m (p-type, power factor of 0.30 mW/K² - m). The cooling performance of devices with 60 thermoelectric pairs and a column width of 40 μm is evaluated under a minimal cooling load (thermobuoyant surface convection and surface radiation). The average cooling achieved is about 1 K. Fabrication challenges include the reduction of the column width, implementation of higher substrate temperatures for optimum thermoelectric properties, and improvements of the top connector patterning and deposition. [ABSTRACT FROM AUTHOR]

Abstract: Ferrography was first introduced into China over 20 years ago. Since then, academic research on wear debris formation mechanisms, intelligent identification of wear particle and other aspects have been carried out. Successful application of ferrography to machine condition monitoring in industry has been achieved with attendant cost benefits. Academic research has accelerated the development of ferrography, in which British scientists have made a considerable contribution to it. The future of ferrography is encouraging. [Copyright &y& Elsevier]

Abstract: Since 1971, when ferrography was first introduced, there have been many developments in the techniques used to process samples and also the way in which debris is analysed and interpreted in relation to the underlying causes that produced them. The science and application of ferrography embraces both the engineering and medical fields and this has led to new and exciting ways of understanding the associated phenomena and how to extract the best information for the advancement of the subject matter. The purpose of this special issue is to provide an overview of some of the principal developments that have taken place over the past three decades, thereby placing on record what is widely acknowledged to be one of the most significant developments in the field of wear debris technology. [Copyright &y& Elsevier]

This paper begins with a survey of the way that signs for labour and skill had been deployed in printed pictures before the advent and triumph of photomechanical printmaking in the generation after 1870. It then surveys the take-up of the two main photomechanical relief techniques (the line-block and the half-tone screen), and the persistence of wood-engraving, in the major illustrated weeklies from London end Paris from 1870 to 1900, relating the use of different techniques to the problem of how to signify the value of the pictures that these magazines offered. The second half of the paper discusses the way that this same problem was negotiated in two very different sorts of printed commodities around 1900, the London art-collectors' magazine The Connoisseur, and the cheap single sheets, carrying pictures made by José Guadalupe Posada, printed and sold in Mexico City by Antonio Vanegas Arroyo. This paper shows that despite being radically dissimilar commodities, these two cases both demonstrate the depth of the crisis that photomechanical technologies had induced in the way that men and women in the Western world could understand the worth and purpose of printed pictures. [ABSTRACT FROM AUTHOR]

Abstract: We demonstrate a method to fabricate microscopic topographic patterns over a large area. The idea is based on anisotropic dewetting of a previously rubbed polymer film. Two types of patterns are demonstrated. One contains well aligned parallel micro-grooves with widths and separations of about 1μm. The other contains striped domains of micro-grooves oriented parallel and orthogonal to the stripes in alternation. Although the pattern formation had been demonstrated on 2×2cm2 substrates, this method is scalable to any substrate size and could offer an attractive low-cost alternative to photolithography and soft lithography in very large area applications. [Copyright &y& Elsevier]

This article presents a hands-on classroom photolithography laboratory module to explore nanotechnology. Photolithography, literally meaning light-stone-writing in Greek, is the process by which patterns on a semiconductor material can be defined using light. All nanometer-sized electronic components are made using this process. Photolithography involves using energy to change the solubility of a chemical, which is then "developed" to create a pattern. An image can be produced on a surface by drawing with light or electrons. It is based upon the notion that oil and water do not mix. So patterns can be made on a surface by drawing with an oily substance, like a crayon, and only where the oily substance was not present would a water-based ink adhere. On the surface a special chemical that is sensitive to light, a photoresist, is applied. The mask is a stencil that allows the energy to pass through only certain regions. So a pattern on a mask can be transferred to a surface by passing light or electrons through the mask.

This article discusses photolithography, which involves the preparation of a microscale polymer silhouettes. Much of today's information technology relies on microchips developed by the semiconductor industry. These microchips are the brains behind most electronic devices such as personal computers, cell phones, and CD players. Although microchip function is typically described in terms of physics and engineering, the underlying process for the fabrication of these complex electronic devices, photolithography, is rooted in polymer chemistry. Developed in 1959, photolithography is a process that uses high-intensity light and a photomask to prepare a polymer network on a silicon wafer. The polymer network is formed through a physical change to a photo resist, which contains a light-sensitive compound and a mixture of polymers that becomes soluble or insoluble when exposed to ultra violet light. The patterned polymer network acts as a guide for the chemical etching of the silicon wafer, much as a canyon channels a river's flow and causes it to carve away the underlying soil.

This paper considers the control wafers safety inventory problem (CWSIP) in the wafer fabrication photolithography area. The objective is to minimize the total cost of control wafers, where the cost includes new wafers cost, re-entrant cost and holding cost while maintaining the same level of production throughput. For the problem under pulling control production environment, a nonlinear programming model is presented to set safety inventory levels so as to minimize total cost of control wafers. A numerical example is given to illustrate the practicality of the model. The results demonstrate that the proposed model is an effective tool for determining the service level of safety inventory of control wafers for each grade. [ABSTRACT FROM AUTHOR]

A new technique incorporating a diamond anvil cell with photolithographic and film deposition techniques has been developed for electrical resistivity measurement under high pressure. Molybdenum was sputtered onto a diamond anvil facet and patterned to the desired microcircuit. A sputtered Al2O3 (alumina) layer was then fabricated onto the Mo-coated layer to insulate the thin-film electrodes from the metallic gasket and to protect the electrodes against plastic deformation under high pressure conditions. For better insulation, Al2O3 was also sputtered onto the metallic gasket. The regular shape of the microcircuit makes it convenient to perform an electric current field analysis, hence, accurate resistivity data can be obtained from the measurement. We performed the measurement of nanocrystalline ZnS to 36 GPa and determined its reversibility and phase transition hysteresis. [ABSTRACT FROM AUTHOR]

Abstract: In the photolithography processing of semiconductor, the line width becomes smaller and smaller. Therefore, the requirements of process window are stricter than before. Among them, the control of focus and exposure dose is one of the most important factors that may affect the line width. Bad control of focus and exposure may not only affect line width, but also cause the increment of rejects of products. The research mainly explored the effects of focus and exposure dose on line widths of different photo resists. The research obtained related coefficients of exposure dose line width and focus line width by coating photo resist of different components on the surface of the silica wafer. The results of research found that focus may not only change line width but also had a positive–negative symmetric relationship with line width. It also found that there was linear relationship between exposure dose and line width. [Copyright &y& Elsevier]

Gold (Au) nanoparticles were deposited inside silica: (SiO2) shells containing cadmium sulfide (CdS) nanoparticles through photocatalytic reduction of potassium dicyanogold(I) by CdS. Photocatalytic Au deposition occurred only when core-shell nanoparticles having a void space between the core and shell, i.e., a jingle-bell-shaped structure, were used. These core-shell nanoparticles were prepared by size-selective photoetching of SiO2 -covered CdS nanoparticles. The size of Au nanoparticles could be controlled by adjustment of the void space in SiO2-covered CdS. Dissolution of CdS by acid treatment from the Au-deposited jingle-bell nanoparticles did not have any effect on the surface-plasmon absorption by Au. These facts indicate that Au nanoparticles of adjustable size can be prepared in an SiO2 shell that prevents mutual coalescence of Au nanoparticles but allows permeation of molecules and ions. [ABSTRACT FROM AUTHOR]

Cross-linked liquid-crystalline polymer films were prepared by polymerization of mixtures containing azobenzene monomers and cross-linkers with azobenzene moieties. Two types of the cross-linked liquid-crystalline polymer films were prepared: monodomain films and polydomains films. Photoirradiation of the monodomain films with UV linearly polarized light (LPL) gave rise to bending of the films toward actinic light along the polarization direction, when the light polarization was parallel to the rubbing direction. When the two directions were perpendicular to each other, the bending was isotropic without a preferential direction. On the other hand, exposure of the polydomain films to UV LPL led to bending of the films always along the polarization direction of the actinic light. This means that one can induce bending of the film along any direction precisely by choosing the polarization direction of the actinic light. [ABSTRACT FROM AUTHOR]

We report colloid crystal growth by using electrodeposition of charged polymer colloid particles on patterned conductive substrates. We used photolithography to create patterns with conductive grooves and dielectric ribs on indium-tin oxide surfaces. Two approaches were used to enhance long-range order in two-dimensional colloid crystals grown on patterned surfaces: (i) patterning of substrates with features commensurate with several particle diameters and (ii) patterning of substrates with features commensurate with a single particle diameter. We demonstrate the effect of commensurability on colloid crystal growth and present the results of real-time studies of colloid crystallization in constrained geometry during electrodeposition on patterned substrates. [ABSTRACT FROM AUTHOR]

Single-mode polymeric channel waveguides were fabricated using simple direct ultraviolet photolithography process. A cross-linkable negative tone epoxy NANOTM SU-8 2000 polymer was used. Once exposed to ultraviolet light through a photomask, the waveguide stripes were obtained upon development. The polymer has many desirable properties, such as high refractive index, good adhesion to substrate, optical transparency in the infrared wavelength region, and high glass transition and high thermal decomposition temperatures. Properties of the optical waveguides were characterized, and there is an excellent agreement between measured data and theory. The values of dn/dT and waveguide birefringence are -1.87×10-4 /°C and ~10-4, respectively, and are comparable to those of halogenated acrylate polymers. With an overcladding layer, the propagation losses measured are 0.25 and 0.28 dB/cm at 0.8 µm, 0.62 and 0.77 dB/cm at 1.31 µm, and 1.25 and 1.71 dB/cm at 1.55 µm for TE and TM polarizations, respectively. [ABSTRACT FROM AUTHOR]

Abstract Microlens array is an important optical element to improve the photosensitivity of charge-coupled device (CCD). In this paper, a monolithic integration technology between microlens and 528 528 element PtSi Schottky-barrier infrared charge-coupled device (IRCCD) with a pixel size of 30m 30m has been developed. The microlens array with low sag and long focal length is designed based on geometrical optics theory. It is directly formed on the back side of the substrate in IRCCD chip using successive photolithography and A+ ion beam etching (IBE) technology. The microlens array is characterized by both surface stylus and point spread function (PSF). The experiment results of integration device between IRCCD and microlens array indicate that the optical signal response is improved obviously and a responsivity increase by a factor of 1.8 in the operation band. [ABSTRACT FROM AUTHOR]

Inductive coupled plasma (ICP) etching with Ar/O2 plasma system has been investigated for diamond device fabrication. High etch rate of 40 μm/h and etch selectivity of diamond to aluminium, which acts as a hard mask, of 50 were obtained. Dot patterns of aluminium with 1-μm diameters were prepared by lift-off or conventional photolithography and etching processes. Gas flow rates of Ar and O2 were 30 and 90 sccm, respectively, and total pressure was between 2 and 7 Pa. ICP power was in the range of 700–1000 W. It was found that the change of power supplied to substrate allowed the change in diamond feature after etching. During anisotropic etching, bias power of 200 W was supplied and cylindrical shape with vertical wall was formed. On the contrary, isotropic etching without bias power formed eroded sidewall underneath the aluminium-masks. By combining these two conditions, we succeeded in forming top-recessed cylinders and bottom eroded ones. Conical structures of diamond with sharp tip, of which the minimum radius of curvature was less than 10 nm, were also fabricated by using tapered aluminium mask or partial sidewall etching on diamond cylinder. [Copyright &y& Elsevier]

Microscopic mechanisms of photomechanical spallation are investigated in a series of large-scale molecular dynamics simulations performed for molecular and metal targets. A mesoscopic breathing sphere model is used in simulations of laser interaction with molecular targets. A coupled atomistic-continuum model that combines a molecular dynamics method with a continuum description of the laser excitation and subsequent relaxation of the conduction band electrons is used for metal targets. Similar mechanisms of the laser-induced photomechanical spallation are observed for molecular and metal targets. For both target materials, the relaxation of compressive stresses generated under conditions of stress confinement is found to be the main driving force for the nucleation, growth and coalescence of voids in a subsurface region of an irradiated target at laser fluences close to the threshold for fragmentation. The mechanical stability of the region subjected to the void nucleation is strongly affected by the laser heating and the depth of the spallation region in bulk targets is much closer to the surface as compared with the depth where the maximum tensile stresses are generated. Two stages can be identified in the evolution of voids in laser spallation, the initial void nucleation and growth, with the number of voids of all sizes increasing, followed by void coarsening and coalescence, when the number of large voids increases at the expense of the quickly decreasing population of small voids. The void volume distributions are found to be relatively well described by the power law N(V)∼V-τ, with exponent gradually increasing with time. Comparison of the simulation results obtained for Ni films of two different thicknesses and bulk Ni targets suggests that the size/shape of the target plays an important role in laser spallation. The reflection of the laser-induced pressure wave from the back surface of a film results in higher maximum tensile stresses and lower threshold fluence for spallation. As the size of the film increases, the locations of the spallation region and the region of the maximum tensile stresses are splitting apart and the threshold fluence for spallation increases. [ABSTRACT FROM AUTHOR]

The mechanisms of photomechanical spallation are investigated in a large-scale MD simulation of laser interaction with a molecular target performed in an irradiation regime of inertial stress confinement. The relaxation of laser-induced thermoelastic stresses is found to be responsible for the nucleation, growth, and coalescence of voids in a broad sub-surface region of the irradiated target. The depth of the region subjected to void evolution is defined by the competition between the evolving tensile stresses and thermal softening of the material due to the laser heating. The initial void volume distribution obtained in the simulation of laser spallation can be well described by a power law. A similar volume distribution is obtained in a series of simulations of uniaxial expansion of the same molecular system performed at a strain rate and temperature realized in the irradiated target. Spatial and time evolution of the laser-induced pressure predicted in the MD simulation of laser spallation is related to the results of an integration of a thermoelastic wave equation. The scope of applicability of the continuum calculations is discussed. [ABSTRACT FROM AUTHOR]

Patterning with sub-diffraction-limited resolution has been demonstrated using a simple photolithography technique. Evanescent fields and surface plasmons are critical to the image formation, which is investigated here using computer simulations and experiments. A regime exists in which surface plasmons are resonantly excited, which we have named Evanescent Interferometric Lithography (EIL); period halving and reduced exposure times characterize this exposure mode. Two other exposure modes have been investigated in which surface plasmons on a planar metallic film beneath the mask are used to improve pattern formation. In the first, Planar Lens Lithography (PLL), a planar silver layer excited near its plasma frequency is used to form a projected near-field image. For a 40-nm thick silver layer, we predict that resolution down to 40 nm should be possible. However, the image is affected by the loss in the silver layer, the mask period, duty cycle and surrounding refractive index. Experimental verification of PLL is presented for 1-micron period structures imaged through 120 nm of silver. Finally, simulations are used to show that surface plasmons on an underlying silver layer can be used to improve process latitude and depth of field. We have named this mode Surface Plasmon Enhanced Contact Lithography (SPECL). [ABSTRACT FROM AUTHOR]

Azobenzene (Az)-containing polymers provide fascinating photoresponsive actuation systems. When they are organized at interfaces, the motion of Az unit occurring at a molecular (sub-nano) scale can be transferred and amplified to larger scales of materials. This review article focuses to selected research topics on organized layer systems of Az-containing polymers proceeding in our laboratory. They involve i) photomechanical response of monolayers at nanometer levels in thickness and centimeters in area, ii) monolayer-mediated photoorientation of polymer (polysilane) and mesoporous silica at nano- to sub-micrometer levels in thickness, and iii)instant mass migration triggered by patterned photoirradiation occurring at distances over micrometer levels. In every system, strong cooperative interplays between the Az unit and organized molecular or macromolecular assemblies play the essential roles. Promotions of these research areas are anticipated to provide wide and new opportunities for material processing and creation of new classes of photofuncitional soft materials. [ABSTRACT FROM AUTHOR]

The possibility of periodical mask fabrication with elements of minimal size by means of interference photolithography is considered. The method is based on application of striped interference picture of coherent light for photoresist exposition. The investigation of inorganic photoresist based on chalcogenide glass As2S3 reveals high resolution, sufficient contrast and vertical edge of the masks stripe. The influence of exposure dose and development parameters on photoresist profile are analyzed with the help of the method of computer simulation of the development process. The possibility of decreasing the effect of standing light wave by means of additional homogeneous light irradiation is demonstrated. The optimal conditions for minimum size elements fabrication are found, which enables fabrication of periodical grating with a 80-nm-wide line and two-dimensional periodical structures with pillars of 50 nm cross-section. [ABSTRACT FROM AUTHOR]

A solid freeform fabrication (SFF) technique is described where powder is deposited layer-by-layer using electrophotographic printing. In the electrophotography process, powder is picked up and deposited using an electrostatically charged surface. A test bed was designed and constructed to study the application of electrophotography to SFF. It can precisely deposit powder in the desired shape on each layer. A polymer toner powder was used to build small components by thermally fusing each layer of printed powder using a hot compaction plate. The feasibility of 3D printing using this approach was also studied by printing a binder powder using electrophotography on to a part powder bed. [ABSTRACT FROM AUTHOR]

The polarization is analyzed in four microwave bursts with one loop-top and two footpoint sources observed at 17 GHz with the Nobeyama Radioheliograph (NoRH). The loop-like structure of the four events is confirmed by simultaneous SOHO/MDI magnetograms and TRACE/EUV images or Yohkoh/SXT images. The heliocentric distance of the four events is greater than 30°. The three microwave sources in each given burst are polarized in the same sense. This may be interpreted in terms of extraordinary mode emission, taking into account the polarity of the underlying magnetic field and propagation effects, which may lead to inversion of the sense of polarization in the limbward foot and loop-top source of the flaring loop. [ABSTRACT FROM AUTHOR]

We developed a code for the reconstruction of nonlinear force-free and non-force-free coronal magnetic fields. The 3D magnetic field is computed numerically with the help of an optimization principle. The force-free and non-force-free codes are compiled in one program. The force-free approach needs photospheric vector magnetograms as input. The non-force-free code additionally requires the line-of-sight integrated coronal density distribution in combination with a tomographic inversion code. Previously the optimization approach has been used to compute magnetic fields using all six boundaries of a computational box. Here we extend this method and show how the coronal magnetic field can be reconstructed only from the bottom boundary, where the boundary conditions are measured with vector magnetographs. The program is planed for use within the Stereo mission. [ABSTRACT FROM AUTHOR]

The photoluminescence (PL) color of silica glass changes from weak blue to intense white under irradiation with 325 nm laser light at room temperature in vacuum. Irradiation at room temperature with the same laser light under oxygen gas atmosphere erases the white PL state. Through many successive experiments, it is found that the spectral change is a reversible phenomenon. Such intense white PL state is stored for a long time at room temperature in air under room light after removal of the laser light, in spite of any changes of atmosphere. The observed phenomenon may relate to the photo-induced defect formation at the silica glass surface. Such observed reversible phenomenon may well yield materials for erasable optical information storage, oxygen sensors and white-light emitting devices. [Copyright &y& Elsevier]

To clarify whether photomechanical response is limited to the special combination of azobenzene (AzBz)/organophilic tetrasilicic mica (TSM) complexes, another swelling synthetic fluoro-mica, lithium taeniolite, was used as a starting host for AzBz/organophilic mica complexes. Basal spacings of organophilic taeniolites (o-TNs) prepared by the intercalation of trimethylalkylammonium (TMAA) into the TN increased linearly as alkyl chain length in TMAA increased from 2.44 to 2.86 nm. This indicates paraffin-type arrangement of TMAA in the TN gallery. Intercalation of AzBz to o-TN was performed via the gas phase at 100 °C. Photoresponses of AzBz/o-TN complexes were examined by XRD measurement under alternate UV and visible light irradiation. A decrease in basal spacing was observed under UV irradiation, and an increase was under visible light irradiation. Basal spacing change was 0.09–0.18 nm, which corresponds to 3–5% of the AzBz/o-TN basal spacing. These results indicate that reversible photomechanical response is a general phenomenon for AzBz/organophilic mica complexes. [Copyright &y& Elsevier]

This paper delineates a comprehensive and successful application of decision tree induction, to 1054 records of production lots taken from a lithographic process with 45 processing steps. Complex interaction effects among manufacturing equipment that lead to increased product variability have been detected. The extracted information has been confirmed by the process engineers, and used to improve the lithographic process. The paper suggests that decision tree induction may be particularly useful when data is multidimensional, and the various process parameters and machinery exhibit highly complex interactions. Another implication is that on-line monitoring of the manufacturing process (e.g., closed-loop critical dimensions control) using data mining may be highly effective. [ABSTRACT FROM AUTHOR]

Microfluidic devices with a dual function containing both a solid-phase extractor and an enzymatic microreactor have been prepared, and their operation has been demonstrated. The devices were fabricated from a 25-mmlong porous poly(butyl methacrylate-co-ethylene dimethacrylate) monolith prepared within a 50-μm-i.d. capillary. This capillary with a pulled 9-12-μm needle tip was used as a nanoelectrospray emitter coupling the device to a mass spectrometer. Photografting with irradiation through a mask was then used to selectively functionalize a 20mm-long portion of the monolith, introducing reactive poly(2-vinyl-4,4-dimethylazlactone) chains to enable the subsequent attachment of trypsin, thereby creating an enzymatic microreactor with high proteolytic activity. The other 5 mm of unmodified hydrophobic monolith served as micro solid-phase extractor (μSPE). The dual-function devices were used in two different flow directions; concentration of myoglobin that was absorbed from its dilute solution, followed by elution and digestion or digestion, followed by concentration. Operations in both directions afforded equal sequence coverage. Different volumes of myoglobin solution ranging from 2 to 20 μL were loaded on the device. Very high sequence coverages of almost 80% were achieved for the highest loading. Despite the very short length of the extractor unit, the device operated in the digest-solid-phase extraction direction also enabled the separation of peaks that mostly contained undigested protein and peptides. [ABSTRACT FROM AUTHOR]

Several optical methods for in-situ displacement measurement are presented as a tool to characterize thermomechanical behavior of microelectronics subassemblies. Features and recent developments of the methods are reviewed and applications to diverse problems are illustrated to demonstrate wide applicability of the methods. The whole-field displacement information, with various sensitivity and resolution scales, is ideally suited for the deformation study of a broad range of problems in microelectronics packaging. The methods are mature and they can be practiced routinely. More applications are anticipated. [ABSTRACT FROM AUTHOR]

A method for rapid prototyping based on electrophotographic powder deposition was investigated to study its potentials and to identify design and implementation challenges. This technique is referred to here as the electrophotographic rapid prototyping (ERP). In this technique, powder is printed layer-by-layer in the shape of the cross-sections of the part using electrophotography a very widely used non-impact printing method. Each layer of powder is consolidated by fusing before the next layer of powder is printed. A fully automated test bed was constructed that consists of a printing system, fusing/heating plate, build platform that has two-degrees of freedom as well as software that drives the system. [ABSTRACT FROM AUTHOR]

This study asks whether photomechanical movements in the retinal cells of the lateral eye of the American horseshoe crab, Limulus polyphemus, are controlled locally within each ommatidium, or whether they are a retinal array property involving lateral communication between ommatidia. Three experiments were performed. A small spot, a vertical slit down the center, or the anterior third of an otherwise masked eye was illuminated. The contralateral eye was fully illuminated in each experiment and served as a light-adapted control. Morphometric analyses of aperture length and rhabdom dimensions were made from serial 1-µm plastic sections. The results suggest there is a different spatial threshold for photomechanical movement for aperture lengthening than for rhabdom lengthening. When only a few ommatidia are illuminated, the aperture does not change. When about 10% are illuminated, they lengthen, but the masked ommatidia do not. When about a third are illuminated, all the ommatidia in the eye lengthen together, including the two thirds that were masked. When either only a few ommatidia or about 10% of the ommatidia are illuminated, rhabdom shape is unchanged. When a third of the eye is illuminated, the illuminated rhabdoms lengthen, but the masked rhabdoms do not. [ABSTRACT FROM AUTHOR]

Examines the crystal and solution structures of photochromic spirobenzothiopyran. Elucidation on the spirobenzothiopyram; Analysis of molecular structure of the zwitterionic photomercyanine; Details on the nuclear magnetic resonance.

A separate-type two-dimensional 8 × 3 folded-slot array antenna was fabricated using photolithography and wet etching, and the receiving properties for 94-GHz millimeter wave radiation were investigated theoretically and experimentally in order to improve the receiving gain of a separate-type slot antenna. The fabricated folded-slot array antenna had a power gain of 12.5 dBi which was 10.5 dB larger than the single slot antenna at 94 GHz. This power gain was almost the same value as a monolithic-type 8 × 3 slot array antenna within 0.5 dB. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 84(1): 91–98, 2001 [ABSTRACT FROM AUTHOR]

The photogalvanic effect was studied in a photogalvanic cell containing EDTA as reductant, methylene blue + toluidine blue as photosensitizer. The photopotential and photocurrent generated were 742.0 mV and 110.0 µA, respectively. The observed conversion efficiency was 0.5398 per cent and the maximum output of the cell was 81.62 µW. The photogalvanic cell can be used for 34.0 min in the dark. The effects of different parameters on the electrical output of the cell were observed and a mechanism has been also proposed for the generation of photocurrent in the photogalvanic cell. Copyright © 2000 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Focuses on the photographic collection of John Walter Osborne in the United States. Background of Osborne; Use of photomechanical processes developed by Osborne to produce line work in advertising and illustration; Purpose of photomechanical printing.

Transcutaneous drug delivery has been the subject of intensive research. In certain situations, rapid transcutaneous delivery is very desirable. A mechanical (stress) pulse generated by a single laser pulse was shown to transiently increase the permeability of the stratum corneum in vivo. The barrier function of the stratum corneum recovers within minutes. The increased permeability during these few minutes allows macromolecules to diffuse through the stratum corneum into the viable epidermis and dermis. Macromolecules (40 kDa dextran and 20 nm latex particles) were deposited into the skin using a photomechanical pulse generated by a single 23 ns laser pulse. This treatment can potentially be utilized in therapies that currently require occlusive dressings for hours or day(s). [ABSTRACT FROM AUTHOR]