Over 27% efficiency GaAs/InGaAs mechanically stacked solar cell

We have applied an InGaAs solar cell (band GAP = 0.75 eV) to the bottom cell of the super-high-efficiency tandem solar cell aiming an over 35% conversion efficiency. The InGaAs cell which is lattice-matched to the InP substrate showed the efficiency of 5.5% under the GaAs substrate with low carrier concentration. Combining with the GaAs cell by means of a mechanically stacking technique, we obtained an efficiency of 28.8% at air mass (AM) 1.5, 1-sun. This result suggests the possibility of the cells with the efficiency of over 35% with combining a GalnP/GaAs monolithic tandem cell and the InGaAs cell (or InGaAsP cell).     

Enhancement of soft magnetic properties of FeCoNbB nanocrystalline alloys with Cu and Ni additions

The magnetic properties of annealed Fe₄₂Co₄₂Nb₇B₈Cu_0.5Ni_0.5, Fe₄₂Co₄₂Nb₆B₈Cu₁Ni₁ and Fe_42.5Co_42.5Nb₆B₈Cu_0.5Ni_0.5 alloys produced by melt spinning have been studied. By simultaneous addition of Cu and Ni elements, the soft magnetic properties of nanocrystalline FeCoNbB alloy with high Curie temperature were greatly improved. The annealed alloys show high Curie temperature of more than 1223 K and excellent soft magnetic properties, i.e., low coercivity of about 30 A/m and high effective permeability of above 5000, and these values are superior to the typical nanocrystalline HITPERM alloys for high temperature applications.     

Low-temperature synthesis of copper conductive film by thermal decomposition of copper-amine complexes

Copper conductive film was synthesized at low temperature onto a glass substrate by thermal decomposition of complexes of copper (II) formate and n-octyl amine in nitrogen atmosphere. The film generated by calcination above 110 °C indicated electrical conductivities, resulting in the lowest resistivity of 2 × 10^− 5 Ω cm by calcination at 140 °C. The copper conductive film consisted of spherical copper nanoparticles that were a mixture of large and small particles, which resulted in low volume resistivity.     

Investigation of false triggering mechanism

This paper discusses a problem that a half‐bridge circuit can generate, namely a false trigger by high‐speed switching transition. In general, a false trigger occurs by charging a gate–source capacitance because of high‐speed voltage transition and influx of current via a reverse transfer capacitance. Therefore, it is thought that the ratio of the input capacitance and the reverse transfer capacitance is important to check whether a false trigger occurs. However, we find another reason and propose a novel assumption. A novel false triggering mechanism appears by considering the source‐side parasitic inductance. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Polymeric micelles modified by folate-PEG-lipid for targeted drug delivery to cancer cells in vitro

A novel technique was developed for the formation of ligand-targeted polymeric micelles that can be applicable to various ligands. For tumor-specific drug delivery, camptothecin (CPT)-loaded polymeric micelles were modified by folate to produce a folate-receptor-targeted drug carrier. Folate-linked PEG5000-distearoylphosphatidylethanolamine (folate-PEG5000-DSPE) was added when preparations of drug-loaded polymeric micelles, resulting in folate ligands exposed to the surface. Folate-modified CPT-loaded polymeric micelles (F-micelle) were evaluated by measuring cellular uptake using a flow cytometer, fluorescence microscopy, and confocal laser scanning microscopy, and by cytotoxicity measurement. The results revealed that F-micelle showed higher cellular uptake in KB cells overexpressing folate receptor (FR) and higher cytotoxicity compared with non-folate modified CPT-loaded polymeric micelles (plain micelles) in KB cells, but not in FR-negative HepG2 cells. This result indicated that polymeric micelles were successfully modified by the folate-linked lipid.     

Radiocarbon (14C) diurnal variations in fine particles at sites downwind from Tokyo, Japan in summer

The radiocarbon ((14)C) of total carbon (TC) in atmospheric fine particles was measured at 6 h or 12 h intervals at two sites, 50 and 100 km downwind from Tokyo, Japan (Kisai and Maebashi) in summer 2007. The percent modern carbon (pMC) showed clear diurnal variations with minimums in the daytime. The mean pMC values at Maebashi were 28 ± 7 in the daytime and 45 ± 16 at night (37 ± 15 for the overall period). Those at Kisai were 26 ± 9 in the daytime and 44 ± 8 at night (37 ± 12 for the overall period). This data indicates that fossil sources were major contributors to the daytime TC, while fossil and modern sources had comparable contributions to nighttime TC in the suburban areas. At both sites, the concentration of fossil carbon as well as O(3) and the estimated secondary organic carbon increased in the daytime. These results suggest that fossil sources around Tokyo contributed significantly to the high daytime concentration of secondary organic aerosols (SOA) at the two suburban sites. A comparison of pMC and the ratio of elemental carbon/TC from our particulate samples with those from three end-member sources corroborates the dominant role of fossil SOA in the daytime.     

Study on Rotational Frequency Noise in a Centrifugal Compressor for Automobile Turbochargers简

The rotational frequency noise （also known as the pulsation noise） due to the mistuning of impeller blade rows introduced at the manufacturing stage of the impellers is observed in the small-sized centrifugal compressor for automobile turbochargers. The present paper addresses the elucidation of the generating mechanism and parame- ter dependency such as the kind and degree of mistuning. In order to analyze numerically the rotational frequency noise due to mistuning, the unsteady computational fluid dynamics （CFD） of the whole compressor including vo- lute is executed, and the resultant time history of the pressure is fed into the spectral analysis.     

Determination of docosahexaenoic acid in milk using affinity solid-phase purification with argentous ions and modified thin layer chromatography

This paper reports a simple method for docosahexaenoic acid determination in bovine milk. The method consists of three steps: (1) one-step DHA methylation in bovine milk without lipid extraction, (2) concentration of DHA methyl ester by AgNO₃-modified silica gel column chromatography, and (3) detection of DHA methyl ester using spot focused-high performance thin layer chromatography. DHA was directly methylated in bovine milk and selectively concentrated in accordance with its intrinsic affinity to argentous ions. Purified DHA methyl ester was developed on newly designed thin layer chromatographic plates with focusing slits and determined densitometrically using conventional software, following visualisation with iodine staining. In addition to the densitometrical analysis, it is also possible for practical, semiquantitative DHA determination to be visually performed on site in manufacturing industries. Unlike conventional methods, the method described needs neither lipid extraction procedures that use a large amount of organic solvent, nor a gas chromatograph system.