Development of Superconducting Multilayer Wiring for Large Arrays of TES X-Ray Microcalorimeters

We are developing TES (Transition Edge Sensor) X-ray Microcalorimeters for future X-ray astronomy missions such as DIOS (Diffuse Intergalactic Oxygen Surveyor). Standard wiring for a large-format array requires narrow and closely-packed configuration. This can cause deleterious crosstalk especially in the Frequency Domain Multiplexing readout. Hence we have employed multilayer wiring technique. In this paper, we tested a deposition of a TES film on the multilayer wiring by sputtering. Our first trial showed that the TES pixels have large residual resistances >50?mΩ and small critical currents of <1?μA. To improve the coverage of the TES film on the wiring, we increased the thickness of TES film (Ti/Au thickness of 100/200?nm). Also to remove an oxidation layer on the Al wiring, we strengthened a reverse-sputtering (150 W, 3?min) before the sputtering of TES. After these treatments, the TES film showed a sharp transition with small residual resistance (～1?mΩ) and large critical current (>30?μA).     

Fabrication of Ni compound nanocrystal/nanocarbon composites by cooling of chloride-based fluxes

Unique Ni compound nanocrystals were successfully grown on carbon nanotubes (CNTs) by cooling a mixed chloride flux. Cup-stacked CNTs (CSCNTs) were used as the nanocarbon materials because of their structural features. The grown nanocrystals had a nanosheet structure, which was densely assembled and had a ribbon-like morphology. Therefore, the nanocrystal/CSCNT composites were expected to have a highly active surface area for the catalyst composites. The selected area electron diffraction pattern and the related radial intensity profiles indicated that the grown nanocrystals were Ni(OH)2. When the pristine CSCNTs were used as a starting material, the formation efficiency of the nanocrystal/CSCNT composites decreased because the pristine CSCNTs were not dispersed in the KCl-LiCl flux. Therefore, functionalization of the CSCNTs was carried out with VUV light irradiation. The dispersibility of the VUV light-treated CSCNTs increased in the KCl-LiCl flux in comparison with the pristine CSCNTs because oxygen-containing functional groups, such as -COOH and -CO, were introduced onto the surfaces of the CSCNTs.     

Mechanical properties of nano-silica particulate-reinforced epoxy composites considered in terms of crosslinking effect in matrix resins

In this study, the mechanical properties of nano-silica particulate-reinforced epoxy composites with different crosslinking densities were clarified experimentally to consider the interaction effects between nano-particles and the network structure in matrix resin. The matrices were prepared by curing with an excessive mixture of diglycidyl ether of bisphenol A type epoxy resin as the curing agent for the stoichiometric condition. The volume fraction of the silica particles with a median diameter of 240 nm was constantly 0.2 for every composite. The crosslinking densities and glass transition temperatures of the neat epoxy resins were identified from thermo-viscoelastic properties measured by dynamic mechanical analysis. Elastic moduli and strengths of the composites and the neat epoxy resins were measured by three-point bending tests. The glass transition temperatures of the neat epoxy resins decreased linearly as the crosslinking densities decreased from the stoichiometric condition. The glass transition temperatures of the composites were reduced by adding the nano-silica particles. The bending moduli of the composites in the glassy state could be predicted by using a mixture law of the composites regardless of the crosslinking densities and glass transition temperatures. The bending strengths were found to be sensitive to the crosslinking densities: they were both higher (for composites with high crosslinking densities) and lower (for composites with low crosslinking densities) than those of the neat epoxy resin. These results demonstrate that the interaction between nano-particles and network structures reduces the bending strengths, especially for low crosslinking densities.     

Hydrometallurgical process for the recycling of copper using anodic oxidation of cuprous ammine complexes and flow-through electrolysis

Flow-through electrolysis for copper electrowinning from cuprous ammine complex was studied in order to develop a hydrometallurgical copper recycling process using an ammoniacal chloride solution, focusing on the anodic oxidation of cuprous to cupric ammine complexes. The current efficiency of this anodic oxidation was 96% at a current density of 200 A m⁻² under a batch condition. In a flow-through electrolysis using a sub-liter cell and a carbon felt anode, the anodic current efficiency increased with the flow rate and was typically higher than 97%. This tendency was explained by the backward flow of the cupric ammine complex, which was formed on the anode, through the diaphragm. The anodic overpotential was lower than 0.3 V even at an apparent current density of 1500 A m⁻². A similar current efficiency and overpotential were also achieved in a liter scale cell, which indicates the scale flexibility of this electrolysis. The power consumption requirements for copper electrowinning in this cell were 460 and 770 kWh t⁻¹ at the current densities of 250 and 500 A m⁻², respectively, which were much lower than that of the conventional copper electrowinning despite the longer interpolar distance.     

Synthesis and application of fluorescein- and biotin-labeled molecular probes for the chemokine receptor CXCR4

The design, synthesis, and bioevaluation of fluorescence- and biotin-labeled CXCR4 antagonists are described. The modification of D-Lys8 at an epsilon-amino group in the peptide antagonist Ac-TZ14011 derived from polyphemusin II had no significant influence on the potent binding of the peptide to the CXCR4 receptor. The application of the labeled peptides in flow cytometry and confocal microscopy studies demonstrated the selectivity of their binding to the CXCR4 receptor, but not to CXCR7, which was recently reported to be another receptor for stromal cell-derived factor 1 (SDF-1)/CXCL12.     

Fabrication of highly crystalline NbOx nanotube/cup-stacked CNT nanocomposites

Carbon nanotubes (CNTs) are promising catalyst supports for fuel cell applications. Metal oxide/CNT nanocomposites are also being studied for dye-sensitized solar-cell, photocatalyst, and sensor applications. The fabrication of nanocomposites consisting of highly crystalline NbOx nanotubes and cup-stacked carbon nanotubes (CSCNTs) is reported herein. The CSCNTs were selected for the carbon materials because of their distinctive structure. The CSCNTs were photochemically treated with vacuum ultraviolet light, which increased the amount of oxygen-containing functional groups therein. NbOx nanotubes with no defects were successfully prepared with the chemical treatment of highly crystalline, layered, flux-grown K4Nb6O17 crystals. First, K4Nb6O17 crystals were grown from a KCl flux at a holding temperature of 800 degrees C. Next, NbOx nanosheets were prepared from the layered K4Nb6O17 crystals via a two-step exfoliation process, which consists of proton exchange in an acid solution and intercalation of the tetrabutylammonium ions. The NbOx nanosheets were rolled up into nanotubes with diameters of about 20 nm and lengths of 100-500 nm on the surfaces of the CSCNTs; thus, unique and complex NbOx/CSCNT nanocomposites were successfully fabricated.     

Prediction of carcass composition and individual carcass cuts of Japanese Black steers

The objective of this study was to develop equations to predict carcass tissue weights and percentages and boneless carcass non-trimmed cut weights by using the cold carcass weight (CCW) and three other traits at the 6–7th rib section, which are routinely collected in carcass markets in Japan. Carcasses from 94 Japanese Black steers were used for the multiple regression analysis with a stepwise procedure and a novel Least Absolute Shrinkage and Selection Operator (LASSO). The accuracies of prediction (R²) and RMSEs for the carcass tissue and cut weights were similar between the two procedures. In contrast, LASSO appeared to be the better procedure for predicting carcass tissue percentages. The longissimus muscle area and subcutaneous fat thickness were the important predictors for the lean percentage in the stepwise procedure, and CCW was additionally selected when the LASSO procedure was used.     

Short channel characteristics of quasi-single-drain MOSFETs

It is clearly demonstrated that source/drain (S/D) elevation is remarkably effective in suppressing the short channel effect against the shrinkage of gate sidewall spacers in MOSFETs. Even if the gate sidewall width is reduced to as very thin as 15 nm, the short channel effect is effectively suppressed by means of the highly elevated S/D regions (80 nm in the present case), though the characteristics of conventional MOSFETs are drastically degraded. This result is explained in terms of the fact that the serious influence due to the deep S/D implantation is suppressed by the formation of a quasi-single-drain configuration. Furthermore, the parasitic S/D resistance decrease, which will bring about drivability enhancement, was observed for reduction in the sidewall width. These favorable experimental results may indicate the definite necessity of elevated S/D engineering for future ultrashort MOSFETs     

Cultural variation in the use of current life satisfaction to predict the future.

Three studies examined cultural and situational influences on the tendency for people to use their current life satisfaction to predict future life events. On the basis of the self-enhancement literature, it was predicted that either writing about a positive personal experience or reading about another's negative experience would lead European Americans to focus their attention on internal attributes and thus would lead them to use their current life satisfaction in predicting the future. Conversely, on the basis of the self-criticism literature, it was predicted that these same conditions would lead Asian Americans to focus their attention on external factors and, therefore, would decrease their likelihood of using their current life satisfaction to predict the future. Studies 1 and 2 supported these hypotheses. Study 3 showed that these patterns could be obtained by subliminally priming concepts associated with individualism and collectivism. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Junction capacitance reduction due to self-aligned pocketimplantation in elevated source/drain NMOSFETs

A new advantage of an elevated source/drain (S/D) configuration to improve MOSFET characteristics is presented. By adopting pocket implantation into an elevated S/D structure which was formed by Si selective epitaxial growth and gate sidewall removal, we demonstrate that the parasitic junction capacitance as well as the junction leakage was significantly reduced for an NMOSFET while maintaining its good short channel characteristics. These successful results are attributed to the modification of the boron impurity profile in the deep S/D regions. The capacitance reduction rate, furthermore, was more remarkable as the pocket dose was further increased. This means that the present self-aligned pocket implantation is very promising for future MOSFETs with a very short gate length, where high pocket dosage will be required to suppress the short channel effect