Optimization of interface structures in crystalline silicon heterojunction solar cells

In heterojunction solar cells consisting of hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-Si), suppression of epitaxial growth at the heterointerface is found to be crucial to achieve high solar cell efficiencies. In order to avoid the epitaxial growth, wide-gap hydrogenated amorphous silicon oxide (a-SiO:H) has been applied to the heterojunction solar cells. We have fabricated a-SiO:H/c-Si solar cells using n-type and p-type c-Si substrates and demonstrated that incorporation of the a-SiO:H i layer prevents the harmful epitaxial growth at the heterointerface completely.     

Luminescent properties of doped freestanding silicon nanocrystals embedded in MEH-PPV

We demonstrate that the electrochemical etching and pulverization of porous silicon films allow the fabrication of boron- and phosphorous-doped freestanding silicon nanocrystals (Si-ncs). The presence of boron in freestanding Si-ncs was confirmed from low-temperature photoluminescence (PL) analysis. The temperature dependence of PL for both types of doped Si-ncs reveals two PL bands due to the quantum confinement effect and surface state defects. Blending of Si-ncs into poly[methoxy-ethylexyloxy-phenylenevinilene] polymer leads to suppression of the PL band originated from surface states. More importantly, those blends showed a photoconductivity response under illumination AM1.5 at room temperature.     

Back surface reflectors with periodic textures fabricated by self-ordering process for light trapping in thin-film microcrystalline silicon solar cells

Back surface reflectors (BSRs) with grating structures have been developed to enhance light trapping in thin-film hydrogenated microcrystalline Si (μc-Si:H) solar cells. As a grating structure, a periodic honeycomb-like dimple pattern with a period of ～450 nm has been fabricated on Al substrates by a self-ordering process using anodic oxidation of Al. The clear diffraction effect has been confirmed on the patterned Al from the angle-dependent reflection. From quantum efficiency measurements, we found that the periodically patterned BSR can confine the incident light more effectively than the random textured BSR, especially at longer wavelengths.     

Improvement of Stainless Steel Making Operation Adapting Instable Raw Material Price

Sumikin Iron and Steel Corporation (SISC) is the main manufacturing base of seamless tube materials in Sumitomo Metals group, and stainless steel making plant is in charge of semi‐manufactured special steel products such as stainless and high alloy steel. Total manufacturing costs of these special steels are heavily dependent on the price of raw material. Therefore, reduction of its usage and optimizing operation process in order to absorb influence of its unstable price are important issues. In this report, we introduce three cases as following: yield improvement in order to reduce raw material usage, optimization of the steel dust usage, and active use of low‐price raw material through dividing refining process.     

cDNA cloning, gene expression and subcellular localization of anthocyanin 5-aromatic acyltransferase from Gentiana triflora

Acylation of anthocyanins with hydroxycinnamic acid derivatives is one of the most important and less under-stood modification reactions during anthocyanin biosynthesis. Anthocyanin aromatic acyltransferase catalyses the transfer of hydroxycinnamic acid moieties from their CoA esters to the glycosyl groups of anthocyanins. A full-length cDNA encoding the anthocyanin 5-aromatic acyltransferase (5AT) (EC 2.3.1.153) that acylates the glucose bound at the 5-position of anthocyanidin 3,5-diglucoside was isolated from petals of Gentiana triflora on the basis of the amino acid sequence of the purified enzyme. The isolated full-length cDNA had an open reading frame of 469 amino acids and the calculated molecular weight was 52,736. The deduced amino acid sequence contains consensus motifs that are conserved among the putative acyl CoA-mediated acyltransferases, and this indicates that 5AT is a member of a proposed superfamily of multi-functional acyltransferases (St-Pierre et al. (1998) Plant J. 14, 703-713). The cDNA was expressed in Escherichia coli and yeast, and confirmed to encode 5AT. The enzymatic characteristics of the recombinant 5AT were consistent with those of the native gentian 5AT. Immunoblot analysis using specific antibodies to 5AT showed that the 5AT protein is present in petals, but not in sepals, stems or leaves of G. triflora. RNA blot analysis showed that the 5AT gene is expressed only in petals and that its expression is temporally regulated during flower development coordinately with other anthocyanin biosynthetic genes. Immunohistochemical analysis demonstrated that the 5AT protein is specifically expressed in the outer epidermal cells of gentian petals and that it is localized mainly in the cytosol.     

Removal of selected pharmaceuticals by chlorination, coagulation-sedimentation and powdered activated carbon treatment

Removal property of nine pharmaceuticals (clofibric acid, diclofenac, fenoprofen, gemfibrozil, ibuprofen, indomethacin, ketoprofen, naproxen and propyphenazone) by chlorination, coagulation-sedimentation and powdered activated carbon treatment was examined by laboratory-scale experiments under the conditions close to actual drinking water treatment processes. Indomethacin and propyphenazone were completely degraded by chlorination within 30 minutes, but others remained around 30% (naproxen and diclofenac) or more than 80% of the initial concentration after 24 hours. A couple of unidentified peaks in a chromatogram of the chlorinated samples suggested the formation of unknown chlorination by-products. Competitive adsorption was observed when the mixed solution of the target pharmaceuticals was subjected to batch adsorption test with powdered activated carbon. Clofibric acid and ibuprofen, which were relatively less hydrophobic among the nine compounds, persisted around 60% of the initial concentration after 3 hours of contact time. Removal performance in actual drinking water treatment would become lower due to existence of other competitive substances in raw water (e.g. natural organic matter). Coagulation-sedimentation using polyaluminium chloride hardly removed most of the pharmaceuticals even under its optimal dose for turbidity removal. It is suggested that the most part of pharmaceuticals in raw water might persist in the course of conventional drinking water treatments.     

Intra-aortic ultrasonography in advanced esophageal cancer

Bisphosphonates are a group of chemical substances which have been used in medicine for thirty years in the treatment of skeletal diseases and disorders of calcium metabolism. Bisphosphonates are derived from pyrophosphate by substitution of an O atom for a C atom. This structure makes possible a number of variants by changing the side-chains of the C atom. The basic P-C-P bond is very thermostabile and completely resistant to enzymatic hydrolysis. The basic biological property of bisphosphonates is inhibition of bone resorption but has not been completely elucidated so far. The prerequisite is the inhibitory action of bisphosphonates on osteoclast activity. The latter are inhibited only when they are in contact with bone surfaces which contain bisphosphonates. Another possible mechanism of action of bisphosphonates is their action on osteoblasts: osteoblasts produce local growth factors which inhibit osteoclasts and thus osteoresorption is inhibited. So far it is not exactly known whether the direct effect on osteoclasts, the indirect effect via osteoblasts or a combination of both are the most important effect of bisphosphonates on the resorption of bone.