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This article proposes to investigate how the reproduction of images impacted the conditions for the dissemination of scientific knowledge, based on strategies of representation and visual communication. As historical techniques of image reproduction, it is understood here the manual engraving of the matrix (i.e., xylography, chalcography and lithography) that preceded the photomechanical processes until the end of the 19th century. As a case study, the research was conducted by visual representations of the bird-of-paradise - an exotic bird, originating from islands in Southeast Asia, inaccessible to Europe at the time - addressing how it makes itself known to a wider audience, through printed images. Questions related to the modes of visual representation and graphic techniques will be addressed as fundamental attributes for understanding the theme, discussing their different languages, characteristics, limitations and potentialities for the domain and acquisition of knowledge mediated by information design. [ABSTRACT FROM AUTHOR]

This paper describes a simple and inexpensive apparatus for measuring the light-induced shape change of a material, which can be implemented in a high school or undergraduate laboratory. The key components of the apparatus are a laser pointer to actuate the material, a force sensor from an inexpensive jeweler's balance to measure the response, an Arduino for data acquisition, and a means for mechanically mounting the setup. The apparatus described here was used by high school students and teachers in a summer program to characterize liquid crystal elastomer samples. The theory of photomechanical response is used to interpret the gathered data, from which material parameters related to this theory are determined. [ABSTRACT FROM AUTHOR]

Abstract We propose a scale-bridging methodology to link the microscopic photoreaction of an azobenzene-containing liquid crystalline polymer (LCP) and the macroscopic interfacial and elastic properties of carbon nanotube (CNT)-reinforced photo-responsive nanocomposites. The photo-isomerization of the azobenzene moieties is described by implementing a photo-switching potential that represents the light-excited energy transition path. The relevant time evolution of the molecular shape and the concurrent changes in the interfacial morphology are observed using molecular dynamics (MD) simulations. Finally, the effective elastic properties of the photo-responsive polymer (PRP) nanocomposite with respect to the isomerization ratio are numerically derived using the micromechanics-based homogenization method. It is verified that the size of the CNT and the photo-deformation of the azobenzene molecules influence the intermolecular interactions and the nematic phase of the LCP at the interfacial region. The continuum-scale finite element (FE) model, which reflects the microscopic information, clearly predicts the reinforcing effect of the CNT filler on the elastic properties of the composite and their variation under photo-actuation. We expect our results to shed light on designing the photomechanical energy conversion efficiency of nano-sized soft actuators composed of CNT-reinforced composites. [ABSTRACT FROM AUTHOR]

The design of the adaptive mechanical behavior of polymer nanocomposites driven by light irradiation has attracted considerable attention in the fields of physical chemistry and mechanical engineering. To assess the photo-mechanical properties of photo-responsive polymer (PRP) nanocomposites reinforced with gold nanoparticles via continuum mechanics, we first investigated interfacial properties of PRP nanocomposites by using a novel multiscale multiphysical model. Particularly, the interfacial interactions between the nanoparticle and polymer matrix under external loading were addressed by combining all-atom molecular dynamics (MD) simulations with finite element (FE) analysis. To explicitly characterize the role of the interfacial interactions between the nanoparticle and polymer matrix in strain energy density under photo-mechanical loading, the effective stiffness and the spatial range of the interphase layer were numerically identified by matching the deformation energy in the FE model with that in the MD model using the energy method and the homogenization theory. It is verified that the equivalent continuum model obtained by the multiscale method satisfactorily predicts not only the overall mechanical properties of nanocomposites, but also the local stress distribution at the interphase as well as the inherent nanoparticle size and photo-isomerization reaction effects of the nanocomposites. The present multiscale analysis reveals that the effective interfacial region around the nanoparticle is considerably weakened as the photo-isomerization reaction progresses, as well as the decrease of the thickness of the interfacial region. [ABSTRACT FROM AUTHOR]

In this paper, we propose a metaheuristic for solving an original scheduling problem with auxiliary resources in a photolithography workshop of a semiconductor plant. The photolithography workshop is often a bottleneck, and improving scheduling decisions in this workshop can help to improve indicators of the whole plant. Two optimization criteria are separately considered: the weighted flow time (to minimize) and the number of products that are processed (to maximize). After stating the problem and giving some properties on the solution space, we show how these properties help us to efficiently solve the problem with the proposed memetic algorithm, which has been implemented and tested on large generated instances. Numerical experiments show that good solutions are obtained within a reasonable computational time. [ABSTRACT FROM AUTHOR]

The effect of ultraviolet light produced ozone and irradiation (UV/ozone) cleaning on the surface properties and interface electrical properties of 4 unit cell (uc) LaAlO3/SrTiO3 samples is examined. A standard photolithography process is used to contaminate the samples which are then cleaned in UV/ozone. Atomic force microscopy measurements show that the photoresist contaminated samples can be cleaned efficiently using this method. The surface roughness of the cleaned samples is comparable to that of the as-grown samples. Furthermore, electrical transport measurements show that the mobility decreases and the sheet carrier density increases for the contaminated samples, which also display indications of an onset to the Kondo effect. By removing the contaminants with UV/ozone cleaning, the mobility and sheet carrier density can be partially restored toward the as-grown values. The mobility is increased by about two times from ≈1000 cm² V-1 s-1 for the contaminated samples to ≈2000 cm² V-1 s-1 for the ozone cleaned ones. [ABSTRACT FROM AUTHOR]

Photomechanical and photochromic activities are reported for single crystals of a new multiresponsive material, 2,4-di-tert-butyl-6-((e)-((4-((E)-phenyldiazenyl)phenyl)imino)methyl)phenol (Azim-1), with two photoactive groups that can undergo photoisomerization (azo and imine), and an ortho-hydroxy group that is capable of proton transfer. Upon irradiation with UV light, platy and needle-shaped crystals of Azim-1 rapidly bend towards the light source and return to their initial shape as soon as the irradiation is terminated. Upon prolonged exposure to UV light, the crystals change their color from yellow to red. The crystal structure of non-irradiated Azim-1 is reported, and the mechanisms of the photomechanical and photochromic responses are discussed. [ABSTRACT FROM AUTHOR]

Westudy light-induced deformation of azobenzene elastomers whichcan display liquid-crystalline (LC) order. It is shown that photomechanicalbehavior of azobenzene elastomers is determined by the strength ofthe LC interactions, which is proportional to the density of rodlikeazobenzene chromophores. At weak LC interactions, a uniaxial orderand uniaxial deformation of azobenzene elastomers along the polarizationvector of the light Eis observed. At strong LC interactions,the light is able to induce a phase transition from the uniaxial tothe biaxial state, with two axes being related to the vector Eand to a preferable alignment of the chromophores in theplane perpendicular to E. The phase transition can beof either the first or the second order. Azobenzene elastomers candemonstrate elongation or contraction along the polarization vector E, depending on the orientation distribution of chromophoresaround the main chains of network strands. The results of the theoryare in a qualitative agreement with experiments and computer simulations,which demonstrate biaxial ordering in azo-containing polymers. [ABSTRACT FROM AUTHOR]

As near-infrared spectroscopy (NIRS) broadens its application area to different age and disease groups, motion artifacts in the NIRS signal due to subject movement is becoming an important challenge. Motion artifacts generally produce signal fluctuations that are larger than physiological NIRS signals, thus it is crucial to correct for them before obtaining an estimate of stimulus evoked hemodynamic responses. There are various methods for correction such as principle component analysis (PCA), wavelet-based filtering and spline interpolation. Here, we introduce a new approach to motion artifact correction, targeted principle component analysis (tPCA), which incorporates a PCA filter only on the segments of data identified as motion artifacts. It is expected that this will overcome the issues of filtering desired signals that plagues standard PCA filtering of entire data sets. We compared the new approach with the most effective motion artifact correction algorithms on a set of data acquired simultaneously with a collodion-fixed probe (low motion artifact content) and a standard Velcro probe (high motion artifact content). Our results show that tPCA gives statistically better results in recovering hemodynamic response function (HRF) as compared to wavelet-based filtering and spline interpolation for the Velcro probe. It results in a significant reduction in mean-squared error (MSE) and significant enhancement in Pearson's correlation coefficient to the true HRF. The collodion-fixed fiber probe with no motion correction performed better than the Velcro probe corrected for motion artifacts in terms of MSE and Pearson's correlation coefficient. Thus, if the experimental study permits, the use of a collodion-fixed fiber probe may be desirable. If the use of a collodion-fixed probe is not feasible, then we suggest the use of tPCA in the processing of motion artifact contaminated data. [ABSTRACT FROM AUTHOR]

Abstract: A three-dimensional (3D) graphene incorporated electrochemical sensor was constructed for sensitive enzyme based phenol detection. To form the 3D graphene structure, polydimethylsiloxane (PDMS) micropillars were fabricated in the microchannel by using a conventional photolithography and the surface was modified with 3-aminopropyltriethoxysilane. Then, the negatively charged graphene oxide sheets were electrostatically adsorbed on the PDMS micropillar surface, and reduced in the hydrazine vapor. The resultant 3D graphene film provides a conductive working electrode as well as an enzyme-mediated sensor with a large surface area. After bonded with an electrode patterned glass wafer, the 3D graphene based electrochemical sensor was produced. Using the 3D graphene as a working electrode, an excellent electron transfer property was demonstrated by cyclic voltammetry measurement in an electrolyte solution containing 1mM K3Fe(CN)6 and 0.1M KCl. To utilize the 3D graphene as an enzyme sensor, tyrosinase enzymes were immobilized on the surface of the graphene micropillar, and the target phenol was injected in the microchannel. The enzyme catalytic reaction process was monitored by amperometric responses and the limit of detection for phenol was obtained as 50nM, thereby suggesting that the 3D graphene micropillar structure enhances the enzyme biosensing capability not only by increasing the surface area for enzyme immobilization, but also by the superlative graphene conductivity property. [Copyright &y& Elsevier]

Photomechanical effects in polymeric materials and composites transduce light into mechanical work. The ability to control the intensity, polarization, placement, and duration of light irradiation is a distinctive and potentially useful tool to tailor the location, magnitude, and directionality of photogenerated mechanical work. Unfortunately, the work generated from photoresponsive materials is often slow and yields very small power densities, which diminish their potential use in applications. Here, we investigate photo-initiated snap-through in bistable arches formed from samples composed of azobenzene-functionalized polymers (both amorphous polyimides and liquid crystal polymer networks) and report orders-of-magnitude enhancement in actuation rates (approaching 102 mm/s) and powers (as much as 1 kW/m3). The contactiess, ultra-fast actuation is observed at irradiation intensities <<100 mW/cm2. Due to the bistability and symmetry of the snap-through, reversible and bidirectional actuation is demonstrated. A model is developed to elucidate the underlying mechanics of the snap-through, specifically focusing on isolating the role of sample geometry, mechanical properties of the materials, and photomechanical strain. Using light to trigger contactless, ultrafast actuation in an otherwise passive structure is a potentially versatile tool to use in mechanical design at the micro-, meso-, and millimeter scales as actuators, as well as switches that can be triggered from large standoff distances, impulse generators for microvehicles, microfluidic valves and mixers in laboratory-on-chip devices, and adaptive optical elements. [ABSTRACT FROM AUTHOR]

[Display omitted] • A recyclable and reprocessable Epoxy/POSS-Azo-EVA composite is prepared. • The composite presents heat- and light-responsive programmable shape-memory effect. • Epoxy/POSS is conducive to improving the shape fixity of the composite. • The recycled composite is processed into a photomechanical device or a smart wire. In this study, an Epoxy/POSS-liquid crystalline azobenzene-Poly (ethylene-co-vinyl acetate) (Epoxy/POSS-Azo-EVA) composite was prepared via the thermal curing of epoxy monomers and multi-functional thiol-containing Polyhedral oligomeric silsesquioxane (POSS) in an EVA matrix. The EVA matrix afforded the composite with shape memory performance. Epoxy/POSS polymer was uniformly dispersed in the matrix to act as a rigid skeleton, leading to the improvement of the mechanical properties and shape memory performance of the composite. Liquid crystalline azobenzene as the photosensitive component provided the inner stress to render the composite film with photo-induced shape-deformation behavior under UV light. The composite film not only exhibited thermal- and light-responsive programmable shape-memory behavior stimulated by heat and light, but also was recyclable and reprocessable. Moreover, the recycled composite film was processed into different functional devices. A flexible photomechanical device based on the recycled Epoxy/POSS-Azo-EVA composite film was fabricated, and the soft device deformed into a hook-shape under UV light and hooked an object whose weight is larger than that of the device. A smart wire was also prepared via assembling a stretched recycled Epoxy/POSS-Azo-EVA composite film and a copper foil by adhesive. The wire could control the status of a circuit via changing its shape under UV light and maintain the status after the removal of light. The functional devices described in this work only needed a short time of UV irradiation during a work cycle, and the devices still held the temporary shape in the absence of UV irradiation. The recyclable and reprocessable Epoxy/POSS-Azo-EVA composite film in this work could provide a creative approach for the fabrication of novel photomechanical devices and soft robotics with energy-saving, intelligence, recyclability, and sustainability. [ABSTRACT FROM AUTHOR]

Abstract: A new class of photomechanical liquid crystal networks (LCNs) has emerged, which generate large bending deformation and fast response times that scale with the resonance of the polymer films. Here, a numerical study is presented that describes the photomechanical structural dynamic behavior of an LCN in a fluid medium; however, the methodology is also applicable to fluid–structure interactions of a broader range of adaptive structures. Here, we simulate the oscillation of photomechanical cantilevers excited by light while simultaneously modeling the effect of the surrounding fluid at different ambient pressures. The photoactuated LCN is modeled as an elastic thin cantilever plate, and gradients in photostrain from the external light are computed from the assumptions of light absorption and photoisomerization through the film thickness. Numerical approximations of the equations governing the plate are based on cubic B-spline shape functions and a second order implicit Newmark central scheme for time integration. For the fluid, three dimensional unsteady incompressible Navier–Stokes equations are solved using the arbitrary Lagrangian–Eulerian (ALE) method, which employs a structured body-fitted curvilinear coordinate system where the solid–fluid interface is a mesh line of the system, and the complicated interface boundary conditions are accommodated in a conventional finite-volume formulation. Numerical examples are given which provide new insight into material behavior in a fluid medium as a function of ambient pressure. [Copyright &y& Elsevier]

Halftoning is an indispensable technique used for showing digital images on screen and printing them on paper using any kind of printer such as Inkjet and Laser. Additionally, halftoning technique has been employed recently in several applications in the computation and communication fields, such as compression and authentication of images, visual cryptography, etc. This article provides as detailed review of the main halftoning methods, such as ordered dither, error diffusion, error diffusion with edge emphasis, dot diffusion, green noise, and direct binary search. For analyzing advantages and disadvantages of each halfoning method, a quality comparison of the halftone image generated by the already named methods was performed using Mean Opinion Score (MOS) measurement. Likewise, computational complexity of each halftoning method was taken into consideration. [ABSTRACT FROM AUTHOR]

We describe the design of micropatterned surfaces for single cell studies, based on thermoresponsive polymer brushes. We show that brushes made of poly(N-isopropylacrylamide) grafted at high surface density display excellent protein and cell anti-adhesive properties. Such brushes are readily patterned at the micron scale via deep UV photolithography. A proper choice of the adhesive pattern shapes, combined with the temperature-dependent swelling properties of PNIPAM, allow us to use the polymer brush as a microactuator which induces cell detachment when the temperature is reduced below 32°C. [ABSTRACT FROM AUTHOR]

We present a simple size reduction technique for fabricating 400 nm zinc oxide (ZnO) architectures using a silicon master containing only microscale architectures. In this approach, the overall fabrication, from the master to the molds and the final ZnO architectures, features cost-effective UV photolithography, instead of electron beam lithography or deep-UV photolithography. A photosensitive Zn-containing sol-gel precursor was used to imprint architectures by direct UV-assisted nanoimprint lithography (UV-NIL). The resulting Zn-containing architectures were then converted to ZnO architectures with reduced feature sizes by thermal annealing at 400 °C for 1 h. The imprinted and annealed ZnO architectures were also used as new masters for the size reduction technique. ZnO pillars of 400 nm diameter were obtained from a silicon master with pillars of 1000 nm diameter by simply repeating the size reduction technique. The photosensitivity and contrast of the Zn-containing precursor were measured as 6.5 J cm-2 and 16.5, respectively. Interesting complex ZnO patterns, with both microscale pillars and nanoscale holes, were demonstrated by the combination of dose-controlled UV exposure and a two-step UV-NIL. [ABSTRACT FROM AUTHOR]

This paper introduces a new design technique for a capacitive gap-coupled bandpass filter (BPF) using non-uniform arbitrary image impedances. Based on the proposed BPF equivalent circuit model, the filter's design equations are derived, and they are validated from comparisons of the calculated and simulated results. For this theoretical verification, the BPF using non-uniform arbitrary image impedances is designed using the specifications of: center frequency (fc) = 5:8 GHz, fractional bandwidth (FBW) = 3:5%, and filter stage (N) = 3. The calculated and simulated results of the designed filter show good agreement. The BPF using the proposed design method could provide an advantage that one can arbitrarily determine two different image impedances, which ultimately affects the BPF's coupling gaps and line widths. This could result in suitable filter dimensions, i.e., gaps and line width, for a conventional low resolution photolithography fabrication although a low or high dielectric constant substrate is used for the design. [ABSTRACT FROM AUTHOR]

Ink-jet print attributes such as color gamut, grain, and cost are consequences of the materials and printing technology used and of choices made during color management, color separation, and halftoning operation. Traditionally, color separation determines what amounts of the available inks to use for each reproducible color, and halftoning deals with the spatial distribution of inks that also results in the nature of their overprinting. However, using an ink space as a means of communication between color separation and halftoning gives access only to some of the printed patterns that a printing system is capable of and, therefore, only to a reduced range of print attributes. Here, a method, i.e., Halftone Area Neugebauer Separation, is proposed to gain access to all possible printable patterns by specifying relative area coverages of a printing system's Neugebauer primaries instead of only ink amounts. This results in delivering prints with more optimal attributes (e.g., using less ink and giving rise to a larger color gamut) than is possible using current methods. [ABSTRACT FROM PUBLISHER]

Photoresponsive fibers based on poly(acrylamide) (PAA) with methylene blue (MB) dye were prepared. All semicircular fibers show bending towards the direction of the flat surface of the fiber when illuminated. The fibers recover their initial shape when the illumination stops. The fiber is heated upon illumination and cooled to room temperature once the illumination is stopped. The fiber also is sensitive to humidity, showing bending behavior towards the direction of the flat surface of the fiber upon changing the humidity. The mechanical energy of the PAA/MB fiber is approximately 0.6 mN for the bending direction when it is illuminated. A possible mechanism for the bending behavior is as follow: (1) the fiber is heated upon illumination because of the photothermal effect, (2) the fiber loses water molecules, (3) the fiber shrinks; bending towards the direction of the flat surface of the fiber occurs because of a difference in the shrinkage for the flat surface and the other side of the fiber. Finally, we demonstrated that a PP ball (1.5 mg) can be moved by the mechanical energy produced by the changing shape of the fiber upon illumination. [ABSTRACT FROM AUTHOR]

Optically directed shape adaptive responses have been sought after for many decades in photoresponsive polymeric materials. A number of recent examinations have elucidated elucidated the unique opportunities of photomechanical responses realized in azobenzene-functionalized liquid crystalline polymer networks (both elastomers and glasses). This work summarizes and contrasts the photomechanical response of glassy polydomain, monodomain, and twisted nematic azo-LCN materials to blue-green irradiation. Building from this summary, the combinatorial photomechanical response observed upon irradiation of composite cantilevers is examined. Large scale shape adaptations are realized, with novel responses that may be of potential use in future employment of these materials in actuation. [ABSTRACT FROM AUTHOR]

Abstract: Light-activated polymers can undergo complex deformation in response to the combination of mechanical and optical stimuli. These materials are attractive for remote actuation and sensing applications. However, the behavior of such materials subjected to photomechanical patterning is not well understood. In this paper we consider a polymer that operates by photoactivated stress relaxation; at the molecular level, photoinitiation of residual initiator molecules generate free radicals that break and then reform in-chain functionalities of stretched chains in an elastomeric network, which results in macroscopic stress relaxation. We carry out experiments and finite element calculations that demonstrate the sequence of deformation events culminating in the formation of a buckled spot as a result of biaxially stretching the elastomeric film then irradiating a circular region followed by releasing the mechanical constraint. In order to better understand the photomechanics, we analyze a simpler model problem wherein a linear elastic, stress relaxing disk is subjected to (i) radial extension, (ii) irradiation of a concentric circular region, and (iii) release of the applied displacements in (i), which results in deformation and stress redistribution. In the final step, the deformation may transition from planar to buckling out of the plane depending on system parameters. Companion finite element calculations are performed against which our analytical results are in good agreement. Although not directly comparable, the analytic model qualitatively agrees with the experiments. The results of this work provide a useful foundation from which to explore more interesting behavior of periodically photo-mechanically patterned films and other more challenging actuation problems. [Copyright &y& Elsevier]

Photoinduced matter motion in thin films containing azobenzene derivatives grafted to a polymer backbone is investigated by means of near-field probe microscopy. We evidence the existence of two different photomechanical processes which produce mass transport. One is governed by the light intensity pattern and the other by the light polarization pattern. The intensity-driven mechanism is found to critically depend on the polymer matrix while the polarization-driven mechanism occurs with almost the same efficiency in different materials. Depending on the relationship between the polarization and intensity patterns, the two processes may either compete or cooperate giving rise to a nontrivial directional mass transport process. [ABSTRACT FROM AUTHOR]

Thin film transistors (TFTs) have been fabricated with a zinc oxide (ZnO) channel layer and a hafnium dioxide (HfO2) gate dielectric layer. The oxide layers were deposited using an atomic layer deposition (ALD) system. The use of ALD for ZnO deposition allows subnanometer thickness control of the deposited layer, and thereby provides a means to vary TFT threshold voltage by controlling the carrier density in the ZnO channel: the carrier density is dependent on the layer thickness because band structure changes result in charge depletion in thinner layers. Enhancement-mode devices have been fabricated and have an on-off current ratio above 106. The enhancement-mode devices of the inverted (gate down) TFT structure were realized by decreasing the ZnO channel layer thickness to 15 nm and below, thereby reducing the carrier density of the as-deposited n-type ZnO layer. An important aspect of the fabrication of the inverted TFTs was the use of either an aluminum sacrificial layer or a thin HfO2 cap layer to eliminate the etching of the ZnO during the photolithography process. The results demonstrate that enhancement-mode TFTs with as-deposited n-type ZnO channels can be produced by tailoring the thickness of the ZnO channel by ALD and are the first reported TFTs in which both the ZnO channel and HfO2 gate dielectric are deposited by ALD to the authors' knowledge. [ABSTRACT FROM AUTHOR]

A novel method of graded junction termination extension (JTE) formation for high-voltage 4H-SiC power devices is presented. Unlike conventional multiimplantation or tapered thickness mask approaches utilizing several photolithography steps, the new termination technique utilizes a single mask with window areas varied laterally away from the main junction, a single-step boron implantation, and drive-in diffusion at elevated temperature. Numerical device simulations have been performed for the initial JTE structure and mask optimization. 4H-SiC p-i-n rectifiers with an active area of 1 mm x 1 mm were fabricated and characterized. The fabricated devices exhibited 2.5-kV blocking voltage, which is close to the theoretical value of an ideal parallel-plane p-n junction. [ABSTRACT FROM AUTHOR]

This paper provides an analysis conducted by means of expanded Murray- Davies model on a transparent substrate which was printed with solvent-based ink and UV ink. The research is based on empirical methods developed using the model (extended Murray-Davies equation derived from the Yule-Nielson model) to define the printed pattern on a substrate in order to improve the quality of reproduction in halftone imaging. Applicability of these equations, developed for research of media such as paper, was examined on a transparent substrate. Model contains two empirically derived parameters "w" and "v", whose determination are based on data from microscopic images. Spectroscopic results were obtained by quantitative spectrometer built with a digital camera. [ABSTRACT FROM AUTHOR]

A method using scatterometry for simultaneous focus and critical dimension (CD) control method has been developed. Our focus and CD measurement method uses a five-layer scatterometry model and provides stable focus measurement when the exposure dose fluctuates. We utilize this feature and consider applying it to the response surface methodology model for focus and CD control. This control optimizes focus and calculates the correct dose allowing for the focus effect. We have confirmed that this method controls photoresist shape accurately and reduces the CD variation for 65 nm devices by 80%. [ABSTRACT FROM AUTHOR]

Structural and chemical compositional changes occurring within the surface region of an organic photoconductor electrically charged with Paschen discharge over an extended period of time have been investigated with the help of attenuated total reflectance Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy. Experimental conditions were selected to simulate interactions between the photoconductor and the plasma discharge occurring in a typical electrophotographic printing environment. A long time exposure of the photoconductor to energetic charged and neutral species, and UV photons impinging upon the photoconductor caused oxidation of the surface, substantial chemical bond breakage, and the reformation of bonding configurations within the region below the surface. These resulted in the formation of a thin surface region with properties different from those of the original photoconductor. Since this study closely follows a modern electrophotographic process, the obtained conclusions are applicable to any electrophotographic printing engine. [ABSTRACT FROM AUTHOR]

Compliant free-standing structures can be used as chip-to-substrate interconnects. Such "compliant interconnects" are a potential solution to the requirements that will be imposed on chip-to-substrate interconnects over the next decade. However, cost of implementation and electrical performance limit compliant interconnects. In our previous work, we have proposed a new compliant interconnect technology called FlexConnect to address these concerns with compliant interconnects. An innovative cost-effective MEMS-based fabrication process is used to fabricate these compliant interconnects. Sequential lithography and electroplating processes with up to two masking steps are utilized. Utilizing the proposed fabrication process, in this paper, FlexConnects are realized at a 100-μm pitch. High-frequency modeling of the electrical parasitics of the interconnect is performed. Through finite-element-based models, the advantage of using multiple electrical paths as part of the interconnect design is shown from a thermomechanical reliability perspective. Finally, taking advantage of the MEMS-based photolithographic fabrication process, a heterogeneous combination of FlexConnects and column interconnects is proposed. This approach is shown to be an additional avenue to attain improved electrical performance without compromising mechanical performance. [ABSTRACT FROM AUTHOR]

By introducing FMEA analysis of Xeikon DCP32D electrophotographic printing model it is shown which components of the machine are weakest link in the printing. Each component is shown separately according to the modules and units of the machine, so that the critical component of each module can be read. By observing the critical component we can improve printing results and minimize cost of production. Solution is in improving critical component and suggestion is to evaluate and validate this component using FMEA analysis. [ABSTRACT FROM AUTHOR]

Abstract: Patternable nanoporous silica thin films with pore sizes on multiple length scales are fabricated using preformed block copolymer/homopolymer blend films as templates. Previous work by Tirumala et al. [V.R. Tirumala, R.A. Pai, S. Agarwal, J.J. Testa, G. Bhatnagar, A.H. Romang, C. Chandler, B.P. Gorman, R.L. Jones, E.K. Lin, J.J. Watkins, Adv. Mater. 18 (8) (2008) 1603] has demonstrated that hydrogen bonding between an amphiphilic copolymer and a homopolymer leads to significant enhancements in the long range order of the template self assembly. However if the copolymer template is simply changed from Pluronic F127 to Brij78, a well ordered template is no longer always obtained; the blend phase separates with apparent selective partitioning of the photoacid generator (PAG) at the interface of the polymer phases. UV exposure selectively generates a photoacid, which is utilized to catalyze tetraethylorthosilicate (TEOS) condensation. The large disparity in diffusivity of the photoacid between the glassy poly(hydroxystyrene) (PHOSt) and rubbery Brij78 phases results in selective templating of the Brij mesostructure and limited reaction into the PHOSt. Calcination yields relatively monodisperse mesopores from the Brij phase and macropores from the PHOSt phase. Simple variations in processing parameters allow the macropore morphology to be tuned to create high surface area materials with structures on the order of 1 nm, 100 nm and μms from self assembly, phase separation and lithographic patterning respectively. [Copyright &y& Elsevier]

Photolithographically-defined patterned arrays of Co-rich Co-Pt permanent magnets with thicknesses up to 10 µm were fabricated by aqueous electrodeposition. These micromagnets exhibited strong perpendicular magnetic performance while being deposited at low temperatures (65° C) and without the need for post-deposition annealing. Co-Pt magnet arrays grown 10-µm thick on textured Cu (111) seed layers on Si (110) substrates exhibited coercivities of 330 kA/m (4.1 kOe) and energy products 69 kJ/m³. Additionally, magnets deposited 8-µm thick on untextured Cu seed layers on standard Si (100) substrates exhibited coercivities up to 260 kA/m (3.3 kOe) and energy products up to 27 kJ/m³. The high magnetic performance and process integrability of these permanent magnet arrays make them well suited for the development of magnetic microelectromechanical systems (MEMS). [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of a series of azobenzene containing liquid crystalline methacrylic homopolymers, poly(4-ω-methacryloyloxy-hexyloxy-4′-ethoxyazobenzene) [Poly(M6A)], with distinct average chain lengths and low polydispersity has been achieved by Atom Transfer Radical Polymerization (ATRP) in THF solution using allyl 2-bromoisobutyrate as initiator and Cu(I)Br as catalyst. Under the adopted conditions the living centers concentration is found to be constant throughout the polymerization process and well defined chain end-groups are obtained. All the obtained polymeric samples, having average molecular mass ranging from 3300 to 14000g/mol, exhibit smectic and nematic liquid-crystalline phases on heating, with transition temperatures strongly dependent on polymerization degree, as characterized by differential scanning calorimetry and polarized optical microscopy. The photomechanical effects (i.e. the dependence of volume and density) exhibited upon trans-to-cis and cis-to-trans photoisomerization of the azobenzene mesogenic groups have been investigated by ellipsometry and related to molecular weight, with particular attention to important parameters for potential applications such as the relative variation of total volume, response time, stability and reproducibility. [Copyright &y& Elsevier]

Insect cuticle is a highly adaptive material that fulfils a wide spectrum of different functions. Cuticle does not only build the exoskeleton with diverse moveable parts but is also an important component of a stunning variety of mechanosensory receptors. Therefore, the mechanical properties of these specialized cuticular systems are of crucial importance. We studied the different cuticular layers of the head part (gula) of the head-to-neck ball articulation of Pachnoda marginata and of the photomechanic infrared (IR) sensilla of Melanophila acuminata on the basis of cross sections. In our study, we combined histological methods (i.e. detection of the different types of cuticle by specific staining) with measurements of hardness (H) and reduced elastic modulus (Er) by nanoindentation technique. In the gula of Pachnoda we found an unusual aberrance from the well-known layering. Between the epi- and exocuticle, two meso- and one endocuticular layers are deposited which are softer and more elastic than the underlyinb exo- and mesocuticular layers. The hardest of all examined materials is the cuticle of the exocuticular shell of the internal sphere of the Melanophila IR sensillum with H=0.53GPa whereas the inner mesocuticular core of the sensillum represents the most elastic and softest layer with values of 11=0.29 GPa and E[subI]=4.8 GPa. Results are discussed with regard to the proposed functions. [ABSTRACT FROM AUTHOR]

In this paper, a proof of concept 4 x 4 active-matrix imager fabricated at near room temperature (<95 °C) is presented. Conventional photolithography and inkjet printing were used to pattern integrated organic FETs and photoconductors. The design and characterization of a pixel circuit is described. A simple first-order calibration technique is used to partially compensate for fixed pattern noise. Following the calibration, the imager is shown to correctly image a "T" pattern. [ABSTRACT FROM AUTHOR]

The photomechanicai properties of carbon nanotubes (CNTs) enable the construction of CNT-based optical actuators. Employing a microelectromechanical systems-compatible nanotube-patterning process by plasma etching, CNT ensembles are integrated into microsystems to realize microoptomechanical systems (MOMS) (CNT-MOMS), where nanotubes behave as both the structural materials and the actuation mechanism. In this paper, following the CNT-MOMS principle, we report on all-optical micromirrors from the CNTs. Photomechanical actuation of single-wall CNTs from polymer-/nanotube-film bimorph structures is designed to actuate the micromirrors. A large mirror angular displacement of 19° is obtained under laser illumination. Bidirectional rotation of the micromirrors is realized by the incorporation of two symmetrical serpentine bimorph actuators with the mirror surface. Furthermore, to add controllability to the micromirror rotations, absorptive-type optical filters are combined with the mirror structure in a "suspended" filter assembly. With green and red optical filters incorporated in the micromirrors, they show rotational selectivities of 10 : 1 and 20 : 1 for the 532- and 658-nm lasers, respectively. Depending on the wavelength of the incoming light, it could be selectively modulated into opposite directions by the micromirror. [ABSTRACT FROM AUTHOR]

Recently, composed vortex fields generated by means of a spatial light modulator working in a dynamical regime have been examined as prospective information carriers. In this paper, an advanced optical set-up utilizing vortices for transfer of information is proposed and experimentally verified. Its operation is based on a sophisticated design of phase-only masks enabling information encoding and decoding. In the proposed vortex communication channel, the photolithographically prepared masks are used for generation of a composed vortex field carrying information. Dynamics of information encoding and decoding is achieved by switching of an array of light sources illuminating the phase masks. [ABSTRACT FROM AUTHOR]

The article explores how "The Studio," a monthly art magazine launched in London, England in April 1893 under the editorial direction of Gleeson White, has used reproduction technologies particularly photomechanical methods to distribute images that would make everyday and transient artifacts worthy of equal consideration to those of fine art. It outlines the significance of the image reproduction decisions of the magazine. It describes the response of collectors to the launch issue of "The Studio" which featured an article on poster collecting.

We describe the micro-mechanical properties of vertically aligned carbon nanotubes (VACNTs) fabricated using a photolithographically patterned iron catalyst prepared using sol–gel techniques. The carbon nanotubes (CNTs) were grown via chemical vapor deposition. The relative mechanical stiffness of the resultant structure was measured using nanoindentation based techniques and is shown to be related to the number of contact sites between tubes. Elastic deformation occurs during compression at large strains, however energy is dissipated during deformation, likely through tube–tube interactions. The effective elastic modulii are depth dependent, due to the compression of pre-buckled geometries. The effective elastic modulii range between 0.03 and 0.08 GPa for a low number of contact sites and 0.1 and 0.3 GPa for a high number of contact sites. [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]

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]

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]

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]

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]

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]

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]

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]

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.