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31.
To improve the cathodic performance of olivine-type LiMnPO4, we investigated the optimal annealing conditions for a composite of carbon with cation doping. Nanocrystalline and the cation-doped LiMn1−xMxPO4 (M = Ti, Mg, Zr and x = 0, 0.01, 0.05 and 0.10) was synthesized in aqueous solution using a planetary ball mill. The synthesis was performed at the fairly low temperature of 350 °C to limit particle size. The obtained samples except for the Zr doped one consisted of uniform and nano-sized particles. The performance of LiMnPO4 was much improved by an annealing treatment between 500 and 550 °C with carbon in an inert atmosphere. A small amount of metal-rich phosphide (Mn2P) was detected in the sample annealed at 900 °C. In addition, 1 at.% Mg doping for Fe enhanced the rate capability in our doped samples. The discharge capacity of LiMn0.99Mg0.01PO4/C was 146 mAh/g at 0.1 mA/cm2 and 125 mAh/g even at 2.0 mA/cm2. 相似文献
32.
Yinxiang Lu Altan Bolag Jun-ichi Nishida Yoshiro Yamashita 《Synthetic Metals》2010,160(17-18):1884-1891
2,2′-(1,4-Phenylene)bis(2,3-dihydro-1H-naphtho[1,8-de]-1,3,2-diazaboroine) [PND] and 2,2′-(4,4′-biphenylene)bis(2,3-dihydro-1H-naphtho[1,8-de]-1,3,2-diazaboroine) [BND] were synthesized and characterized by using differential scanning calorimetry (DSC) measurements, single crystal X-ray structure analysis, UV–vis absorption and electrochemical measurements, thin-film X-ray diffraction (XRD) and AFM studies. Organic field-effect transistors (OFETs) were fabricated by vacuum deposition with a bottom contact geometry using Au electrodes. Annealing treatment optimizes the organic active layer and increases the charge carrier mobility. Field-effect mobilities of 7.2 × 10?3 for PND and 4.1 × 10?4 cm2 V?1 s?1 for BND were found. 相似文献
33.
34.
This work characterizes the structure of C60 nanowhiskers prepared by the liquid-liquid interfacial precipitation method in the C60-saturated m-xylene and isopropyl alcohol system. Transmission electron microscopy and X-ray diffraction measurement show that the C60 nanowhiskers had a hexagonal structure with cell dimensions a = 2.407 nm and c = 1.018 nm which is different from pristine C60. The structure of the C60 nanowhiskers in solution is different from that of the solvated structure reported for the C60 nanotubes but similar to that reported for the C60 bulk crystal solvated with m-xylene. X-ray diffraction analysis also showed a shift to fcc structure after solvent evaporation. The C60 nanowhiskers prepared using toluene as solvent also showed a similar solvated structure, and a more rapid structural change into fcc upon drying was again observed. 相似文献
35.
The multilayered thin films composed diazoresin (DR) and brilliant yellow (BY) were fabricated by a layer-by-layer (LbL) deposition technique, and the ionic bonds between diazonium ion in DR and sulfonate residues in BY were converted to covalent bonds by UV light irradiation. The cross-linking between BY and DR prevented BY from desorption even in a pH 13 solution. The cross-linked (DR/BY)10DR film exhibited pH-dependent absorption spectra in pH 9-13, and the response was repeatable and quick. The pH response time of the films was within a few seconds upon change from pH 9.0 to 13.0, and ca. 40 s upon change from pH 13.0 to 9.0. 相似文献
36.
Summary The peracetylated and free glucose-substituted poly(p-phenylene)s were synthesized by the coupling polymerization of a dibromobenzene monomer using Ni complex and the subsequent
deacetylation by hydrazine monohydrate. The polymerization was carried out using bis(1,5-cyclooctadiene)nickel(0) (Ni(COD)2) as a coupling agent with 2,2’-bipyridyl (bpy) and 1,5-cyclooctadiene (COD) in a mixed solvent of DMF and toluene. The structure
of the product was confirmed by 1H and 13C NMR measurements to be the poly(p-phenylene) having peracetylated glucose residues. The Mn values were estimated by GPC analysis with DMF as eluent to be 7300–9800. The fluorescence analysis of the polymer was carried
out in comparison with that of the dimeric model compound. The CD spectrum of the polymer indicated that the main-chain was
twisted and immobilized in one direction due to the chirality and bulkily of the peracetylated glucose residues. The deacetylation
using hydrazine monohydrate completely took place to give the free glucose-substituted poly(p-phenylene). 相似文献
37.
Jun-ichi Nishizawa Takenori Tanno Takahiro Oohashi Hiraku Watanabe Yutaka Oyama 《Synthetic Metals》2008
The solid-state synthesis of a tetrathiafulvalene–chloranil (TTF–CA) complex was demonstrated, and progress in the formation of the complex was monitored using a GaP Raman terahertz (THz) spectrometer. Clear transitions in the THz absorption spectra indicated that the mixture of TTF and CA became the black phase TTF–CA complex. The results of X-ray diffraction, Raman scattering, and FTIR spectra are presented as supporting evidence. 相似文献
38.
A fungus producing high levels of phytase was isolated from air and identified as Cladosporium sp. The phytase production was stimulated by phytate in the medium used. The maximum production of phytase (108 U/ml) occurred in a medium containing 1.0 g of phytate per 100 ml. The phytase was purified to electrophoretic homogeneity by ion-exchange chromatography and gel filtration. Based on SDS-PAGE analysis, the molecular weight of the purified phytase was calculated to be approximately 32.6 kDa, and the narrow protein band indicated that this phytase is not glycosylated. The phytase has an optimum pH of 3.5, and an optimum temperature of 40 degrees C. The phytase activity was stimulated by 2-mercaptoethanol and dithiothreitol, and inhibited by Ba2+, Pb2+, iodoacetate, p-chloromercuribenzoate and phenylmethylsulfonyl fluoride. The phytase displayed high affinity for phytate and the Km was 15.2+/-3.1 microM. NMR analyses (1D and 2D) indicated that the end hydrolysis product of phytate was myo-inositol 1,2,5-triphosphate. 相似文献
39.
Mutational analysis of structure--activity relationships in human tumor necrosis factor-alpha 总被引:1,自引:0,他引:1
Yamagishi Jun-ichi; Kawashima Hitoshi; Matsuo Noriyuki; Ohue Mayumi; Yamayoshi Michiko; Fukui Toshikazu; Kotani Hirotada; Furuta Ryuji; Nakano Katsuji; Yamada Masaaki 《Protein engineering, design & selection : PEDS》1990,3(8):713-719
To determine the region of human tumor necrosis factor-alpha(TNF-), essential for cytotoxic activity against mouse L-M cells,single amino-acid-substituted TNF- mutant proteins (muteins)were produced in Escherichia coli by protein engineering techniques.An expression plasmid for TNF- was mutagenized by passage throughan E.coli mutD5 mutator strain and by oligonucleotide-directedmutagenesis. Approximately 100 single amino-acid-substitutedTNF- muteins were produced and assayed for cytotoxic activity.The cytotoxic activities of purified TNF- muteins, e.g. TNF-31T,-32Y, -82D, -85H, -115L, -141Y, -144K and -146E, were < 1%of that of parent TNF-. These results indicate that the integrityof at least four distinct regions of the TNF- molecule is requiredfor full biological activity. These regions are designated asfollows: region I, from position 30 to 32; region II, from position82 to 89; region III, from position 115 to 117; region FV, fromposition 141 to 146. In addition, TNF-141Y could not completelycompete with parent TNF- for binding to the receptor. This demonstratesthat region IV, and at least aspartk acid at position 141, mustbe involved in the TNF receptor binding site. 相似文献
40.
Jun-ichi Tomioka Kazuhiro Kiguchi Yohsuke Tamura Hiroyuki Mitsuishi 《International Journal of Hydrogen Energy》2011,36(3):2513-2519
The influence of environmental temperatures on the fatigue strength of compressed-hydrogen tanks for vehicles was investigated. The fatigue strength of Type-3 tanks was found to decrease in a low-temperature environment and increase in a high-temperature environment. The Type-3 tank has been subjected to autofrettage to improve fatigue strength. The investigation clarified that the effect of autofrettage changes according to the environmental temperature due to the difference between the coefficients of thermal expansion of carbon fiber reinforced plastic and aluminum alloy. This causes fatigue strength to change with changes in temperature. The Type-4 tank has a very long fatigue life and did not break after 45,000 cycles in a room-temperature or low-temperature environment. In a high-temperature environment, however, the tank broke in fewer than 45,000 cycles. The fatigue of carbon fiber reinforced plastic was promoted in the high-temperature environment, resulting in breakage of the tank. These results indicate that the fatigue strength of the tanks is influenced by the environmental temperature. 相似文献