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排序方式: 共有568条查询结果,搜索用时 15 毫秒
41.
Semiconductor materials with wide band gap have been extensively used to fabri-cate the blue laser light emitting diodes and ultraviolet photodetectors, which are impor-tant elements of semiconductor instruments, such as displays, optical data storages, ul-traviolet sensors, electroluminescent devices and solar-blind detectors. This kind of ma-terials is now becoming a hot research object in semiconductor physics. GaN was the first suitable ultraviolet laser material people found in this real… 相似文献
42.
Takagi S Frukhtbeyn S Chow LC Sugawara A Fujikawa K Ogata H Hayashi M Ogiso B 《Journal of research of the National Institute of Standards and Technology》2010,115(4):267-276
This study reports for the first time in vitro and in vivo properties of fluorapatite (FA)-forming calcium phosphate cements (CPCs). The experimental cements contained from (0 to 3.1) mass % of F, corresponding to presence of FA at levels of approximately (0 to 87) mass %. The crystallinity of the apatitic cement product increased greatly with the FA content. When implanted subcutaneously in rats, the in vivo resorption rate decreased significantly with increasing FA content. The cement with the highest FA content was not resorbed in soft tissue, making it the first known biocompatible and bioinert CPC. These bioinert CPCs might be useful for applications where slow or no resorption of the implant is required to achieve the desired clinical outcome. 相似文献
43.
44.
A new MBE growth method for the fabrication of a high-quality double hetero-epitaxial Si/γ-Al2O3/Si structure was recently developed. In the present work, characteristics of NMOSFETs fabricated on the Si/γ-Al2O3/Si structure were investigated, and compared with those on a Si/MgAl2O4/Si structure. A γ-Al2O3 layer was created from a MgAl2O4 layer by reaction with Si beams as follows: MgAl2O4 + Si → γ-Al2O3 + SiO ↑ + Mg ↑. The MBE growth of Si on the effectively restructured γ-Al2O3 layer was then performed at a substrate temperature of 700° C, 150° C lower than for the MBE growth of Si on a MgAl2O4/Si substrate. The electron field effect mobility and leakage current between source and drain for the NMOSFETs fabricated
on Si/γ-Al2O3/Si structures were 660 cm2/V · s and 2.8 pA/μm respectively, and exhibited a higher level of performance than those on a Si/MgAl2O4/Si structure. In the Si/MgAl2O4/Si, SIMS measurements confirmed that autodoped Al and Mg atoms near the interface between the Si epi-layer and MgAl2O4/Si substrate diffused anomalously and accumulated at the surface during device fabrication processes. These autodoped Al
and Mg atoms acted as ionized impurities during test operation. Suppression of autodoping from insulator layers during the
MBE growth of Si was thus deemed essential to the improvement of NMOSFET characteristics. In the Si/γ-Al2O3/Si structure, autodoped atoms were scarcely detectable. It was therefore concluded that the Si/γ-Al2O3/Si structure under study was very promising for SOI device applications. 相似文献
45.
46.
To estimate the response to hormone replacement therapy (HRT) by bone metabolic markers, 36 patients with postmenopausal osteoporosis or osteopenia were studied to assess the correlation between percent baseline changes in lumbar bone mineral density (BMD) after 12 months and those in various bone metabolic markers after 3, 6, and 12 months of HRT. All the patients were treated with 0.625 mg of conjugated estrogen and 2.5 mg of medroxyprogesterone per day and continued for 12 months. BMD was significantly increased up to 4.19 +/- 0.87% after 6 months and 4.93 +/- 1.27% after 12 months of HRT (p = 0.0001 by analysis of variance). In accordance with this, changes in the levels of osteocalcin (p = 0.041), alkaline phosphatase (p = 0.0001), N-terminal osteocalcin (p = 0.0001), urinary excretion of pyridinoline/Cr (p = 0.0001), and deoxypyridinoline/Cr (p = 0.0001) were significantly decreased, respectively. Among these bone metabolic markers, only the change in the serum N-terminal osteocalcin at 3 months (r = 0.557, p = 0.0022), at 6 months (r = 0.470, p = 0.0184), and at 12 months (r = 0.545, p = 0.0061) significantly correlated with the change in BMD 12 months after HRT. The elution profiles of immunoreactive osteocalcin-related molecules in serum fractionated by reverse-phase high performance liquid chromatography revealed that the N-terminal fragment as well as the intact osteocalcin molecule decreased after 3 months of HRT. These results demonstrate that N-terminal osteocalcin is a suitable predictor for estimating good responders to HRT in postmenopausal women. 相似文献
47.
Y. Ogata S. Uchiyama M. Hayashi M. Yasuda F. Hine 《Journal of Applied Electrochemistry》1990,20(4):555-558
The pH on the surface of an ion-exchange membrane was measured with a microprobe in a laboratory scale chlor-alkali cell to study the leakage of OH– through the membrane. The solution pH in the vicinity of the membrane facing the anode was found to be considerably higher than that in the bulk solution because of penetration and leakage of OH–. The pH varied with the membrane type. This explains why the carboxylate membrane is not protonated and can be used as a separator in chlor-alkali cells.Deceased. 相似文献
48.
Kunihiro Ogata Tokio Umino Tsuyoshi Nakayama Eiichi Ono Toshiaki Tsuji 《Advanced Robotics》2017,31(6):303-310
Development of clothing in consideration of the shape and body function of a person with spinal cord injury is an important task. Then, a dummy robot with a deformation mechanism was developed in this study for evaluating the comfortable level of clothings. Specifically, a trunk joint mechanism and an abdominal mechanism that can realize various deformations of the abdominal area and various trunk poses were developed. The trunk joint mechanism was implemented in order to simulate the seated posture of persons with spinal cord injury. The abdominal deformation mechanism was implemented using linear actuators and rotating servomotors in order to simulate abdominal obesity of persons with spinal cord injury. Further, a tactile sensor system was developed for measuring the clothing pressure on the abdominal area and evaluating the comfort or discomfort of clothing. 相似文献
49.
We report a new application of affinity capture-elution electrospray mass spectrometry (ACESI-MS) to assay the enzymes phosphomannomutase (PMM) and phosphomannose isomerase (PMI), which when deficient cause congenital disorders of glycosylation CDG-type Ia and type Ib, respectively. The novel feature of this mass-spectrometry-based assay is that it allows one to distinguish and quantify enzymatic products that are isomeric with their substrates that are present simultaneously in complex mixtures, such as cultured human cell homogenates. This is achieved by coupled assays in which the PMM and PMI primary products are in vitro subjected to another enzymatic reaction with yeast transketolase that changes the mass of the products to be detected by mass spectrometry. The affinity purification procedure is fully automated, and the mass spectrometric analysis is multiplexed in a fashion that is suitable for high-throughput applications. 相似文献
50.
M Nakamura T Nagamine K Ogata K Tajima RI Aminov Y Benno 《Canadian Metallurgical Quarterly》1999,38(2):107-112
The degradation kinetics of five glutamine dipeptides in aqueous solution, i.e. glycyl-L-glutamine (Gly-Gln), L-alanyl-L-glutamine (Ala-Gln), L-valyl-L-glutamine (Val-Gln), L-leucyl-L-glutamine (Leu-Gln) and L-isoleucyl-L-glutamine (Ile-Gln), were studied. Stability tests were performed using a stability-indicating high-performance liquid chromatographic assay. Two different Ala-Gln degradation routes, i.e. the cleavage of a peptide bond and the deamination of an amide group, were observed. The degradation was adequately described by pseudo-first-order kinetics. The maximum stability of Ala-Gln was obtained at an approximate pH of 6.0. The pH-rate profile described by specific acid-base catalysis and hydrolysis by water molecules agreed with the experimental results. The activation energy of Ala-Gln at pH 6.0 was determined to be 27. 1kcal mol-1, and the shelf-life (90% remaining) at 25 and 40 degrees C was predicted to be 5.3 years and 7.1 months, respectively. The rate constants of the glutamine dipeptides were influenced by the N-terminal amino acid residue and decreased in the order: Gly-Gln, Ala-Gln, Leu-Gln, Val-Gln and Ile-Gln. 相似文献