Characteristics of dissimilar laser-brazed joints of isotropic graphite to WC–Co alloy

The effect of Ti serving as an activator in a eutectic Ag–Cu alloy filler metal in dissimilar laser-brazed joints of isotropic graphite and a WC–Co alloy on the joint strength and the interface structure of the joint is investigated in this study. To evaluate the joint characteristics, the Ti content in the filler metal was increased from 0 to 2.8 mass%. The laser brazing was carried out by irradiating a laser beam selectively on the WC–Co alloy plate in Ar atmosphere. The threshold content of Ti required to join isotropic graphite to WC–Co alloy was 0.4 mass%. The shear strength at the brazed joint increased rapidly with increasing Ti content up to 1.7 mass%, and a higher Ti content was found to be likely to saturate the shear strength to a constant value of about 14 MPa. The isotropic graphite blocks also fractured at this content. The concentration of Ti observed at the interface between isotropic graphite and the filler metal indicates the formation of an intermetallic layer of TiC.     

Analysis of mark-formation process for phase-change media

The objective of this study was to determine the mechanism of a phenomenon peculiar to phase-change recording regarding the mark shape or mark-forming process. The following results were obtained from our simulation of mark shapes, transparency electron microscope observations, and analysis of reproduced signals. A method of calculating a mark shape by calculating the holding-time profile was devised and its appropriateness was confirmed. We found there were close relationships between the cooling pulse shape, the effective erase ratio, the reproduced signal amplitude, and the noise level, and that the temperature change when the mark edge was cooled has a great influence on the stability of the mark shape and crystallized regions     

Environmental protection: researches in National Institute of Radiological Sciences

Some studies for radiological protection of the environment have been made at the National Institute of Radiological Sciences (NIRS). Transfer of radionuclides and related elements has been investigated for dose estimation of non-human biota. A parameter database and radionuclide transfer models have been also developed for the Japanese environments. Dose (rate)-effect relationships for survival, growth and reproduction have been investigated in conifers, Arabidopsis, fungi, earthworms, springtails, algae, duckweeds, daphnia and medaka. Also genome-wide gene expression analysis has been carried out by high coverage expression profiling (HiCEP). Effects on aquatic microbial communities have been studied in experimental ecosystem models, i.e., microcosms. Some effects were detected at a dose rate of 1 Gy day(-1) and were likely to arise from interspecies interactions. The results obtained at NIRS have been used in development of frameworks for environmental protection by some international bodies, and will contribute to environmental protection in Japan and other Asian countries.     

Phase transition of thermosensitive amphiphilic cellulose esters bearing olig(oxyethylene)s

Summary A series of cellulose esters bearing olig(oxyethylene)s with different degree of substitution (DS) and different length of the oxyethylene chain were synthesized by a homogeneous reaction of cellulose with corresponding monofunctional acid chloride in a 10% LiCl-dimethyl acetoamide (DMAc) solution. The effect of total DS value on the solubility of the derivatives in aqueous solution was investigated. It was found that the lower limit DS value for both water-soluble and amphiphilic derivatives decreases with increasing length of oxyethylene chains. The amphiphilic derivatives, which are soluble in both water and chloroform, precipitate out of aqueous solution on heating without gel forming, such a phase transition behavior was studied in terms of DS value, length of oxyethylene and concentration. The precipitation temperature (T_p) of the amphiphilic derivatives is range from 54°C to 96°C. It decreases with increasing the total DS value, and increases with an increase in the length of oxyethylene chains. The T_p value of the derivatives was found to be almost independent in the concentration range of 1–15 wt %, however the T_p value increases sharply with decreasing polymer concentration when the concentration is lower than 1 wt%. Received: 29 August 2000/Revised version: 16 October 2000/Accepted: 31 October 2000     

Effects of gomisin A on the promotor action and serum bile acid concentration in hepatocarcinogenesis induced by 3'-methyl-4-dimethylamino-azobenzene

The effects of gomisin A, a lignan component of Schizandra fruits, on the promotion stage of hepatocarcinogenesis initiated by 3'-methyl-4-dimethylamino-azobenzene (3'-MeDAB) in male Donryu rats were investigated. When different types of tumor promotors, phenobarbital (PB) and deoxycholic acid (DCA), were administered for 5 weeks after initiation by 3'-MeDAB, preneoplastic alterations in the liver, determined by glutathione S-transferase placental form (GST-P), were markedly increased. Gomisin A significantly inhibited the increase in number and size of GST-P positive foci, regardless of the promotor. This lignan inhibited the increase in serum bile acid concentration by administration of DCA, but hardly influenced the serum bile acids in the PB-combined group. These results suggest that the inhibitory effect of gomisin A on the promotive action of DCA is based on improving bile acid metabolism, but regarding the action of PB, the effect could not be elucidated from the metabolism of bile acids.     

Study on ceramic photonic bandgap structure with three-dimensional diamond lattice

A novel process, which was based on powder injection molding, was investigated for the fabrication of ceramic photonic bandgap structure with three-dimensional diamond lattice. The SiO2-TiO2 ceramic powder was mixed with a water-soluble agent to produce slurry. The slurry was then injected into an epoxy mold with inverse diamond lattice, fabricated by the stereolitographic rapid prototyping process. To increase the density of the green compact, cold isostatic pressing was applied on the unit. Using thermal debinding, the water-soluble agent and the epoxy were extracted at 360 and 650 K, respectively. Sintering was immediately done at 950 K for 5 h and the desired three-dimensional ceramic structure was obtained. The calculated band diagram for this structure indicated the existence of an absolute photonic bandgap for all wave vectors. At 14.7-18.5 GHz, a complete band gap was located with a maximum attenuation of 30 dB at 17 GHz, when transmission was measured in the 〈100〉 direction between 10 and 20 GHz.     

Growth of highly strained GaInAs-GaAs quantum wells on patterned substrate and its application for multiple-wavelength vertical-cavity surface-emitting laser array

We carried out the growth of highly strained GaInAs-GaAs quantum wells (QWs) on a patterned substrate for extending emission wavelength on a GaAs substrate. We examined the shift of photoluminescence wavelength of the QWs and showed a large wavelength shift due to the spatial modulation in well thickness and indium composition. We demonstrated a single-mode multiple-wavelength vertical-cavity surface-emitting laser (VCSEL) array on a patterned GaAs substrate covering a new wavelength window of 1.1-1.2 /spl mu/m. By optimizing pattern shape, we achieved multiple-wavelength operation with widely and precisely controlled lasing wavelengths. The maximum lasing span is as large as 77 nm. We carried out a data transmission experiment through 5-km of single-mode fiber with a 2.5 Gb/s/channel. The total throughput reaches 10 Gb/s. The VCSEL-based wavelength-division-multiplexing (WDM) source would be a good candidate for WDM-LAN beyond 10 Gb/s.     

Enhancement by ganglioside GT1b of annexin I phosphorylation in bovine mammary gland in the presence of phosphatidylserine and Ca2+

Ganglioside GT1b and, to a lesser extent, GD3, enhanced phosphorylation of a 36 kDa protein (the substrate of protein kinase C) in the particulate fraction from bovine mammary gland. Sialic acids, asialogangliosides, and GM3 were without effect, and GD1a conversely inhibited phosphorylation of the 36 kDa protein. The enhanced phosphorylation by GT1b required the simultaneous presence of phosphatidylserine (PS) and Ca²⁺. The 36 kDa protein reacted with anti-annexin I in Western blot analysis. Addition of purified annexin I to the reaction mixture containing the particulate fraction increased the extent of phosphorylated 36 kDa protein, and the phosphorylation was further enhanced by GT1b. The enhanced phosphorylation of annexin I by GT1b was also dependent on PS and Ca²⁺. When annexin I was phosphorylated by purified protein kinase C, GT1b inhibited the annexin I phosphorylation. Addition of epidermal growth factor or insulin to the particulate fraction had little effect on the enhancement. These results suggest that an enzyme or enzymes other than protein kinase C, epidermal growth factor receptor kinase, or insulin receptor kinase is responsible for the GT1b- and GD3-enhanced phosphorylation of annexin I in the presence of PS and Ca²⁺.     

An energy trading system with consideration of CO2 emissions

Abatement of CO₂ emission is one of the most important issues in the 21st century regarding preservation of the earth environment. This paper addresses a utility operations planning problem for distributed energy management systems (DEMSs), where we are to obtain optimal plans that minimize both costs and CO₂ emissions. A DEMS consists of multiple entities that seek their own economic profits. In this paper, we give a mathematical formulation of the utility operations planning problem for each entity, and propose an energy trading market, which utlizes a multi‐attribute auction protocol in order to deal with both a price and a CO₂ emission rate. Experimental results show that collaboration among entities through the market provides a more profitable plan for each entity and abatement of CO₂ emission is also achieved. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(4): 54–63, 2008; Published online in Wiley InterScience ( www.interscience.wiley. com ). DOI 10.1002/eej.20418