XPS analysis of CdS/CuInSe2 heterojunctions

CdS/CuInSe₂ (CIS) heterojunctions were investigated by XPS analysis. An In-excess layer which may form an ordered vacancy compound (OVC) was present at the as-deposited CIS surface and it remained after chemical bath deposition of a CdS layer. The In-excess layer was removed by preferential etching with NH₃ aqueous solution. This result implies that the surface of the as-deposited CIS film was converted from the OVC with n-type conductivity into the CIS with p-type by NH₃ treatment. The conduction band offsets at the CdS/p-CIS and CdS/n-OVC were determined to be 1.0 and 0.3 eV, respectively. The CIS solar cells fabricated with n-OVC surface layer exhibited higher cell efficiencies than those fabricated with p-CIS surface layer.     

Time-alternating method based on single-sideband holography with half-zone-plate processing for the enlargement of viewing zones

The single-sideband method of holography, as is well known, cuts off beams that come from conjugate images for holograms produced in the Fraunhofer region and from objects with no phase components. The single-sideband method with half-zone-plate processing is also effective in the Fresnel region for beams from an object that has phase components. However, this method restricts the viewing zone to a narrow range. We propose a method to improve this restriction by time-alternating switching of hologram patterns and a spatial filter set on the focal plane of a reconstruction lens.     

p-Chlorostyrene oligomers. Preparation,structure, and stereochemistry

The dimer and trimer obtained by the pyrolysis of poly(p-chlorostyrene) were 2,4-di(p-chlorophenyl)-1-butene and 2,4,6-tri(p-chlorophenyl)-1-hexene, respectively, while those obtained by the cationic oligomerization of p-chlorostyrene were trans-1,3-di(p-chlorophenyl)-1-butene and a diastereomeric pair of trans-1,3,5-tri-(p-chlorophenyl)-1-hexene.     

Copolymerization of phenylacetylene with various acetylenes by W- and Mo-based catalysts

In the copolymerization of phenylacetylene with various acetylenes catalysed by WCl₆·Ph₄Sn, the relative reactivity of monomer decreased with increasing steric effect of monomer, e.g. HC  Cn-Bu, HC  Cn-Hex > HC  CPh, HC  Cs-Bu > HC  Ct-Bu, MeCCPh, CICCPh. While 1-chloro-2-phenylacetylene (a disubstituted acetylene) showed high reactivity in the homopolymerization by Mobased catalysts, the reactivity was remarkably depressed in the presence of phenylacetylene as comonomer. Based on these results, the relative reactivity of the acetylenic monomers in copolymerization was explained in terms of competitive coordination of monomers to the propagating end.     

A new blood compatible and permselective hollow fiber membrane for hemodialysis

The authors have prepared a blood compatible and highly permselective hemodialysis membrane composed of polyether segmented nylon. This block copolymer was synthesized by polycondensation of bis-3-aminopropyl-poly(tetramethylene oxide) (PTMO) and poly(imino-1,3-bismethyl-cyclohexyl-iminoisophtharoyl) (NyBl) prepolymer obtained by polycondensation of 1,3-bis(aminomethyl)cyclohexane (B) and isophthalic acid (I). The molecular weight (MW) calculated from the number of end-groups was 16,000-21,000. In vitro blood compatibility was evaluated in terms of platelet adhesion onto the surface. PTMO-NyBl surfaces showed excellent platelet adhesion preventing properties. The PTMO-NyBl hollow fiber membrane was obtained by a dry-wet spinning process. The membranes had higher permeability coefficients for macromolecules ranging from MW 10,000 to 20,000 than polysulfone hollow fiber membrane (PS membrane), and had acceptably low albumin permeability for use as a dialysis membrane. The ex vivo blood compatibilities of PTMO-NyBl membrane and PS membrane were investigated by extracorporeal circulation in a pig model. The PTMO-NyBl membrane gave excellent results when assessing hemodialysis leukopenia, oxidative burst, and free platelet count decrease.     

Development and applications of an analytical electron microscope with a field emission electron gun

An analytical electron microscope with a field emission electron gun has been developed in order to improve the function of material identification, in order to obtain higher resolution of images, sharper electron diffraction patterns, and purer x-ray spectra with no effects of contamination from smaller areas than in the conventional instruments so far utilized. The performance capabilities of this newly developed analytical electron microscope, the Model H-600FE, have been examined and found to be very useful for the material characterization of nanometer-size areas. Various attributes of the microscope became apparent with reference to the results of different studies. These include better convergence of the electron beam (demonstrated by examination of an MoS₂ thin film), high-resolution transmission electron microscopy (using a gold film), high-resolution scanning electron microscopy (with a carbon film containing nanometer-size holes), high-angle resolution electron diffraction (of an iron carbide film), and precision x-ray analysis of nanometer-size areas (using a pyroxene crystal and a Cu---Zn---Al shape memory alloy).     

A 2.5-GFLOPS, 6.5 million polygons per second, four-way VLIWgeometry processor with SIMD instructions and a software bypassmechanism

A four-way very long instruction word (VLIW), 312-MHz geometry processor with peripheral component interconnect/accelerated graphic port bus bridge was implemented in a 0.21-μm, 2.5-V, three-layer-metal CMOS process. We adopted (1) a software bypass mechanism, (2) single-instruction multiple-data stream instructions, (3) four sets of floating-point multiply add and accumulate execution units, (4) special condition code registers and a branch condition generator for a clipping operation, and (5) automatic clock delay tuning methodology. As a result of these features, we achieved a performance of 2.5 GFLOPS and 6.5 million polygons per second for a three-dimensional geometry processor, which is the highest published performance as a single geometry processor. The processor is applicable to computer-aided-design systems that require very high graphics performance