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排序方式: 共有1197条查询结果,搜索用时 406 毫秒
91.
Sachiro Kakinoki Makoto Kitamura Mitsuhiro Yuge Masakazu Furuta Masahito Oka Yoshiaki Hirano Kenji Kono Isao Kaetsu 《Polymer Bulletin》2007,58(2):393-400
Summary Poly(proline) and random copolypeptide composed of Pro and Ala residues were synthesized, and their solution properties and
molecular conformation were investigated. Aqueous solutions of the polypeptide were irradiated with γ-rays above the transition
temperature. It was shown that the transition temperature of the aqueous solution of the copolypeptide is influenced by Ala-residue
content and γ-ray irradiation. 相似文献
92.
Kitamura M. Yamazaki H. Sasaki T. Kida N. Hasumi H. Mito I. 《Photonics Technology Letters, IEEE》1990,2(5):310-311
The spectral linewidth observed in a 1.5 μm multiple-quantum-well distributed-feedback laser diode (MQW-DFB-LD) with 1500 μm cavity length is discussed. The spectral linewidth was drastically reduced in long-cavity MQW-DFB0-LDs through a reduction in threshold carrier density. A spectral linewidth of 250 kHz, the narrowest ever achieved, was obtained 相似文献
93.
94.
Michio Niwano Hideo Kitamura 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1985,234(2):388-393
A new type of undulator greatly improved in tunability as compared with a usual undulator, is proposed. The undulator has a composite magnetic field which is a linear superposition of two sinusoidally varying fields with different spatial periods. The wavelength can be changed by varying the field strength of the longer-period component while keeping that of the shorter-period component at the highest possible value. Numerical calculations of the spectral brightness were carried out. The proper ratios between the two spatial periods were found to be 3:1, 5:1 and 7:1. 相似文献
95.
Bertram I. Cohen Naoyuki Matoba Erwin H. Mosbach Richard J. Stenger Charles K. McSherry 《Lipids》1989,24(6):482-487
Dietary cholic acid (0.1%) and/or calcium (2.6% as calcium carbonate) were added to a semipurified diet containing cholesterol
and ethynyl estradiol to determine whether the incidence of pigment and/or cholesterol gallstones would be changed. Male golden
Syrian hamsters were fed the experimental diets for 96 days (Group 1, control; Group 3, cholic acid plus calcium) or only
an average of 60 days (Group 2, 0.1% cholic acid). Animals in Group 2 became ill (weight loss, low food intake, diarrhea)
possibly due to cholic acid (or deoxycholic acid) toxicity. Cholesterol gallstones and crystals were absent in all experimental
groups. The incidence of pigment gallstones was: control, Group 1, 12/16; 0.1% cholic acid, Group 2, 3/13; and 0.1% cholic
acid plus calcium, Group 3, 11/22. Cholic acid with or without calcium produced an elevation of both liver and plasma cholesterol:
Group 2, 80.1 mg/g and 501 mg/dl; Group 3, 103.7 mg/g and 475 mg/dl vs Group 1, 65 mg/g and 209 mg/dl, respectively. The lithogenic
indices of the bile were lower in Groups 2 and 3 compared to Group 1, controls, 0.45 and 0.58 vs 1.16, respectively. The extent
of the portal tract pathology could not be correlated with the presence or absence of pigment gallstones or with the levels
of lithocholic acid in the hamster bile. In summary, when semipurified diets were supplemented with ethynyl estradiol and
cholic acid, with and without calcium supplementation, no cholesterol gallstones formed and the incidence of pigment gallstones
was not altered. 相似文献
96.
Naoto Kitamura Takuya Hasegawa Yoshiharu Uchimoto Koji Amezawa Yasushi Idemoto 《Electrochimica acta》2011,(25):9453
LiNi0.5Mn0.5O2 was heat-treated under high oxygen-pressure and Ar-reducing conditions, and then the cathode properties, thermodynamic stability and average and local structures were investigated. From X-ray diffraction and ICP measurements, it was found that the pristine LiNi0.5Mn0.5O2 had a single phase of the layered rock-salt structure although the Ni content was slightly rich compared with the nominal one. These characteristics were kept even after the heat-treatments. Charge–discharge cycle tests clarified that the cycle performance of LiNi0.5Mn0.5O2 was improved by both the reducing and oxidizing treatments. From neutron diffraction and X-ray absorption fine structure measurements, the local distortion around the transition metal, especially Ni, was supposed to be one of the important factors to determine the cathode properties. It was also found that the sample with higher thermodynamic stability exhibited better capacity retention in the discharge–charge cycle tests. 相似文献
97.
Hao Yao Shigehito Isobe Yongming Wang Naoyuki Hashimoto Somei Ohnuki 《International Journal of Hydrogen Energy》2013
The thermal decomposition process of lithium alanate (LiAlH4) was investigated by TEM, TG-DTA and XRD. It was shown that LiAlH4 decomposes through a two-step reaction: a liquid-to-solid phase transition in the first step of the decomposition and a solid-to-solid reaction in the second step of the decomposition, both steps accompanied by hydrogen release. The particle size of the aluminum (Al), which formed in the first decomposition step, was much larger than that in the second decomposition step. In addition, Al particles formed in the liquid phase of LiAlH4 in the first decomposition step, while, they form in solid phase of Li3AlH6 in the second decomposition step, resulting in the kinetics of the first decomposition step being faster than that of the second decomposition step. The investigation clearly demonstrated the reaction model of the decomposition of LiAlH4 in the nano-scale, showing different diffusion processes of Al in each of the decomposition steps. 相似文献
98.
We focused on Sr-substituted CePO4—i. e., (Ce,Sr)PO4—with the monazite structure and synthesized the orthophosphates hydrothermally. As for the obtained products, we investigated the particle morphologies by SEM and electrical conduction properties by conductivity measurements. In order to estimate the crystal and electronic structures, neutron and synchrotron X-ray diffraction measurements were also carried out. As a result, it was found that (Ce,Sr)PO4 with a single phase of the monazite structure was successfully prepared by the hydrothermal method and the substitution amount of Sr was almost equal to the nominal one. It was also demonstrated that a powder morphology of the (Ce,Sr)PO4 depended on the synthetic conditions; i.e, concentrations of cation sources and pH of aqueous solution in the hydrothermal process. The Sr-substituted sample showed much higher conductivities than the unsubstituted one, in the same way as the (Ce,Sr)PO4 synthesized by other methods reported previously. 相似文献
99.
The aim of this research is to characterize the organic matter showing endotoxicity in domestic wastewater. It is assumed that endotoxicity is caused by lipo-polysaccharide (LPS), particularly large and hydrophobic molecules. In this study, a batch experiment (decay test for 12 h) was conducted to confirm whether LPS is the cause of endotoxicity or not. 2-keto-3deoxyoctulosonic acid (KDO) was used as an indicator of presence of LPS.A size and structural characterization of several samples from raw and domestic wastewater was also carried out in order know which fractions are causing endotoxicity. Endotoxin and KDO patterns were found to be similar, peaking at the same time. Thus, organic matter showing endotoxicity, such as LPS was released in the decay test. Moreover, the organic matter released from bacteria during decay test was partly biodegradable. Results from size characterization (Molecular Weight Distribution) showed that the majority of endotoxin (up to 82%), in domestic sewage and secondary effluents,is composed of molecules larger than 100 kDa and less than 0.1 μm. Similarly, structural characterization (hydrophobic and hydrophilic) showed that the majority of endotoxin, ranging from 59% to 83% of the total endotoxicity, is hydrophobic fractions. Therefore, removing large and hydrophobic molecules from wastewater can be an effective way to achieve a significant decrease in its endotoxicity. 相似文献
100.