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排序方式: 共有592条查询结果,搜索用时 15 毫秒
21.
Yuta Uemura Toshiaki Shimasaki Naozumi Teramoto Mitsuhiro Shibata 《Journal of Polymer Research》2016,23(10):216
Allylated pyrogallol (A3PG) and acrylated pyrogallol (Ac3PG) as bio-based trienes, and allylated gallic acid (A4GA) and acrylated allyl gallate (Ac3A1GA) as bio-based tetraenes were synthesized from pyrogallol and gallic acid, respectively. Thiol-ene photopolymerizations of the bio-based polyenes and a pentaerythritol-based primary tetrathiol (pS4P) at the allyl/SH ratio of 1/1 produced photo-cured resins (A3PG-pS4P, Ac3PG-pS4P, A4GA-pS4P and Ac3A1GA-pS4P). The FT-IR spectral analysis revealed that thiol-ene reactions of thiol/allyl and thiol/acryloyl groups smoothly proceeded. Gel fractions of acryl-based cured resins were a little higher than those of allyl-based cured resins. The swelling test and dynamic mechanical analysis revealed that GA- and acryl-based cured resins exhibited higher crosslinking densities than PG- and allyl-based cured resins, respectively. A higher order of tan δ peak temperature was Ac3PG-pS4P (48.3 ° C) > Ac3A1GA-pS4P (24.1 ° C) > A4GA-pS4P (22.1 ° C) > A3PG-pS4P (?7.8 ° C). Ac3PG-pS4P displayed the highest 5 % weight loss temperature, tensile strength and tensile modulus among all of the cured resins. 相似文献
22.
Yuta Fujita Akihiro Ametani Keisuke Nakamura Koichi Yamabuki 《Electrical Engineering in Japan》2014,188(1):36-45
This paper investigates the mutual grounding impedance between vertical grounding electrodes based on field measurements and FDTD simulations. In the case of vertical electrodes, the mutual impedance between the electrodes is almost completely independent of the electrode length, and thus the induced voltage is nearly constant as the electrode length becomes longer. This characteristic is different from that of an overhead conductor, where the electromagnetic‐induced voltage is proportional to the conductor length. The greater the separation distance between the electrodes, the smaller the induced voltage, as in the case of an overhead conductor. The propagation speed increases as the separation increases. It is found that the speed is not necessarily proportional to the inverse of the relative permittivity of the earth. 相似文献
23.
Shigenao Maruyama Yuhei Takeuchi Shigeki Hirasawa 《Numerical Heat Transfer, Part A: Applications》2013,63(8):761-776
The radiation element method by ray emission model (REM2) has been improved by using the law of reciprocity for the specular view factor and the incomplete Cholesky conjugate gradient (ICCG) method to reduce computational time. This improved method was applied to analyze the radiative heat transfer between arbitrary three-dimensional bodies composed of specular and diffuse surfaces. The accuracy of the improved method was evaluated by comparing analytical solutions. And the method was used to calculate radiative heat transfer between machine elements and heater panels. CPU time to calculate the radiative exchange for a model composed of 3193 elements was reduced to 1/430 of that by the previous numerical method using a decomposition method. 相似文献
24.
Yuta Shizukawa Shigenari Hayashi Suzue Yoneda Yasumitsu Kondo Hiroshi Tanei Shigeharu Ukai 《Oxidation of Metals》2016,86(3-4):315-326
The phase transformation behavior of a thermally grown oxide scale of FeO on pure-Fe and an Fe–2wt%Au alloy was investigated. Particular attention was paid to formation of a magnetite seam, which is the Fe3O4 layer formed at the FeO/alloy interface at an initial stage of the phase transformation, since it has important effects on the overall phase transformation of FeO scale. A thin Au(Fe) layer was found to develop on the Fe–Au alloy at the FeO/alloy interface after 32 min of oxidation at 750 °C in air. This Au(Fe) layer prevented formation of a magnetite seam and accelerated the FeO eutectoid reaction. The Au(Fe) layer acted as a “chemical diffusion barrier” for inward diffusion of Fe from the FeO to the alloy substrate across the FeO/alloy interface and prevented magnetite seam formation. 相似文献
25.
Poly(p‐phenylene sulfide) (PPS) nanofibers are prepared by irradiating a PPS fiber with a carbon dioxide (CO2) laser while drawing it at supersonic speeds. A supersonic jet is generated by blowing air into a vacuum chamber through the fiber injection orifice. Nanofibers obtained at a laser power of 30 W and chamber pressure of 10 kPa exhibit an average diameter of 600 nm and a draw ratio of 110,000. Scanning electron microscopy, differential scanning calorimetry, and wide‐angle X‐ray diffraction analyses are employed to investigate the relationships among the chamber pressure, fiber morphology, and crystallization behavior. The nanofibers exhibit two melting temperatures (Tm): approximately 280°C and 320°C. The endothermic peak at Tm = 280°C is ascribable to lamellar crystals and that at Tm = 320°C to the highly complete crystals, since the polymer molecular chain is highly oriented. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40922. 相似文献
26.
Naoki Motomura Yuto Yamazaki Daiki Koga Shogo Harashima Xin Gao Yuta Tezuka Kei Omata Yoshikiyo Ono Ryo Morimoto Fumitoshi Satoh Yasuhiro Nakamura Go Eun Kwon Man Ho Choi Akihiro Ito Hironobu Sasano 《International journal of molecular sciences》2022,23(4)
Cortisol-producing adenoma (CPA) is composed of clear and compact cells. Clear cells are lipid abundant, and compact ones lipid poor but associated with higher production of steroid hormones. PRKACA mutation (PRKACA mt) in CPA patients was reported to be associated with more pronounced clinical manifestation of Cushing’s syndrome. In this study, we examined the association of histological features and genotypes with cholesterol uptake receptors and synthetic enzymes in 40 CPA cases, and with the quantitative results obtained by gas chromatography-mass spectrometry (GC-MS) analysis in 33 cases to explore their biological and clinical significance. Both cholesterol uptake receptors and synthetic enzymes were more abundant in compact cells. GC-MS analysis demonstrated that the percentage of compact cells was inversely correlated with the concentrations of cholesterol and cholesterol esters, and positively with the activity of cholesterol biosynthesis from cholesterol esters. In addition, hormone-sensitive lipase (HSL), which catalyzes cholesterol biosynthesis from cholesterol esters, tended to be more abundant in compact cells of PRKACA mt CPAs. These results demonstrated that both cholesterol uptake and biosynthesis were more pronounced in compact cells in CPA. In addition, more pronounced HSL expression in compact cells of PRKACA mt CPA could contribute to their more pronounced clinical manifestation. 相似文献
27.
Shan Liu Jumpei Washio Satoko Sato Yuki Abiko Yuta Shinohara Yuri Kobayashi Haruki Otani Shiori Sasaki Xiaoyi Wang Nobuhiro Takahashi 《International journal of molecular sciences》2022,23(2)
Metformin is a metabolic disruptor, and its efficacy and effects on metabolic profiles under different oxygen and nutrient conditions remain unclear. Therefore, the present study examined the effects of metformin on cell growth, the metabolic activities and consumption of glucose, glutamine, and pyruvate, and the intracellular ratio of nicotinamide adenine dinucleotide (NAD+) and reduced nicotinamide adenine dinucleotide (NADH) under normoxic (21% O2) and hypoxic (1% O2) conditions. The efficacy of metformin with nutrient removal from culture media was also investigated. The results obtained show that the efficacy of metformin was closely associated with cell types and environmental factors. Acute exposure to metformin had no effect on lactate production from glucose, glutamine, or pyruvate, whereas long-term exposure to metformin increased the consumption of glucose and pyruvate and the production of lactate in the culture media of HeLa and HaCaT cells as well as the metabolic activity of glucose. The NAD+/NADH ratio decreased during growth with metformin regardless of its efficacy. Furthermore, the inhibitory effects of metformin were enhanced in all cell lines following the removal of glucose or pyruvate from culture media. Collectively, the present results reveal that metformin efficacy may be regulated by oxygen conditions and nutrient availability, and indicate the potential of the metabolic switch induced by metformin as combinational therapy. 相似文献
28.
Nassim Sahboun Kazuhiro Sawa Yasunori Yamamoto Yuta Watanabe Tomomasa Ito 《Journal of Nuclear Science and Technology》2020,57(9):1111-1120
ABSTRACT In the event of a severe accident, past experiences such as Three Mile Island and Fukushima Daichi have shown that the reactor core of a light-water nuclear reactor, if not properly safeguarded, could go through a meltdown. This will be followed by the formation of a corium, a mix of molten fuel elements, and liquid metals from the Reactor Pressure Vessel (RPV). In the worst-case scenario, a melt through from the RPV can occur and lead to the spreading of the corium, in the form of a molten element’s jet impinging on a flat concrete structure of the Primary Containment Vessel (PCV). To enhance the decommissioning and the safety procedure, scope of the present article is to deepen the understanding of the phenomena involved in the mentioned scenario, mainly jet-instability and molten material spreading. In the present study, experiments were carried out, by using corium simulant materials such as Copper and Tin, to investigate the link between the instability of the gravity-driven molten metal jet and the impinging followed by its spreading over a flat area. 相似文献
29.
The present study uses numerical analysis to investigate the operating methods and costs of an independent microgrid incorporating a sodium–sulfur (NAS) battery or an energy storage system using organic hydrides. Details relating to the operation of the system and its installed capacity and cost were clarified, assuming the introduction of an independent microgrid in Kitami City, a cold region in Japan. Analysis results indicate that energy storage technology using the organic hydride system is economically inferior to the NAS battery owing to large losses associated with the water electrolyzer and dehydration reactor. Therefore, for the widespread use of the organic hydride system, it is necessary to improve the efficiency of these components. 相似文献
30.
A new tomographic reconstruction method is proposed which permits the reconstruction of a region of interest within a slice from partially truncated scanning data. This method utilizes two types of source data, namely a series of truncated projections and the outline of the object's cross section. The principle of this algorithm is to estimate the outside area of truncation in one projection from the projection data of the other viewing angles and the outline data of the object. The above estimation is accomplished by following two repeated procedures: 1) the modification of the calculated projection data compared each time with the already measured projection data of the truncated area, and 2) the modification of the reconstructed image compared also each time with the shape of the object. Computer simulation shows the convergence of the results obtained by this algorithm thus verifying its validity, and a reconstructed image after iterative processes exhibits good quality. 相似文献