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排序方式: 共有813条查询结果,搜索用时 15 毫秒
81.
Dechlorination of chlorobenzene compounds on flyash by using a solution of calcium hydroxide and sulfur in aqueous/organic solvent at 60–170 °C, under oxygen deficient conditions was studied. High percentage of dechlorination was obtained under certain reaction conditions. The results suggested that at 90 °C, metals in general and copper and lead in particular enhanced the catalytic potential of flyash for dechlorination by hydrodechlorination and substitution reactions. But at high temperatures (120–170 °C), dechlorination process was adversely affected by these metals. The effects of water, organic solvents, temperatures and heating time, were studied and reactions conditions were optimized to get maximum dechlorination. 相似文献
82.
The low-temperature synthesis of carbon nanofibers by microwave plasma-enhanced chemical vapor deposition using a CO/Ar/O2 system and their characterizations were performed. At the optimum oxygen concentration of O2/CO = 7/1000, vertically aligned CNFs can be synthesized at temperatures as low as 180 °C with growth rates of 4–6 nm/s. The diameter of bulk CNFs is about 50–100 nm and the surface of CNFs is covered by branching fibers and their nuclei with a diameter of about 5–20 nm. Not only the peaks originating from carbon chains, but also oxygen containing groups, such as CO and COC, are observed in the FTIR spectra. The CNFs growth rate is almost independent from the substrate temperature and it is concluded that an elementary process not on the substrates, but in the gas phase, is the rate-determining step in the present CO/Ar/O2 microwave-plasma-enhanced CVD system. 相似文献
83.
Merry Gunawan Choonbing Low Kurt Neo Siawey Yeo Candice Ho Veluchamy A. Barathi Anita Sookyee Chan Najam A. Sharif Masaaki Kageyama 《International journal of molecular sciences》2021,22(14)
We recently demonstrated that chemical proteasome inhibition induced inner retinal degeneration, supporting the pivotal roles of the ubiquitin–proteasome system in retinal structural integrity maintenance. In this study, using beclin1-heterozygous (Becn1-Het) mice with autophagic dysfunction, we tested our hypothesis that autophagy could be a compensatory retinal protective mechanism for proteasomal impairment. Despite the reduced number of autophagosome, the ocular tissue morphology and intraocular pressure were normal. Surprisingly, Becn1-Het mice experienced the same extent of retinal degeneration as was observed in wild-type mice, following an intravitreal injection of a chemical proteasome inhibitor. Similarly, these mice equally responded to other chemical insults, including endoplasmic reticulum stress inducer, N-methyl-D-aspartate, and lipopolysaccharide. Interestingly, in cultured neuroblastoma cells, we found that the mammalian target of rapamycin-independent autophagy activators, lithium chloride and rilmenidine, rescued these cells against proteasome inhibition-induced death. These results suggest that Becn1-mediated autophagy is not an effective intrinsic protective mechanism for retinal damage induced by insults, including impaired proteasomal activity; furthermore, autophagic activation beyond normal levels is required to alleviate the cytotoxic effect of proteasomal inhibition. Further studies are underway to delineate the precise roles of different forms of autophagy, and investigate the effects of their activation in rescuing retinal neurons under various pathological conditions. 相似文献
84.
The high residual stress in a resin-molded electronic package sometimes makes the electronic functions unstable. Therefore the residual stress in electronic packages, especially on the top surfaces of semiconductor chips, should be evaluated. The objective of this study is to present a simple method for evaluating residual stress in resin-molded semiconductor chips using a combination of experimental and numerical methods. The actual residual stress of the packaging process was measured by using test chips that included piezoresistive gauges. A linear thermoelastic finite element analysis was then carried out using a three-dimensional model. The finite element analysis was performed under a stress-free temperature determined by the temperature dependence of the residual stress, which was experimentally measured by using the piezoresistive test chips. The measured residual stress using the test chips agreed well with the results of the finite element analysis. It was therefore confirmed that the present evaluation method, combining experimental and numerical methods, is reliable and reasonable. 相似文献
85.
Renal ischemia/reperfusion (I/R) injury is one of the main causes of postoperative renal failure. Activated neutrophils are implicated in the development of I/R-induced renal failure. JTE-607 has been reported to be a potent inhibitor of the multiple inflammatory cytokines in the endotoxic shock mouse model and heart Langendorff perfusion model. In this study, we examined whether JTE-607 attenuates I/R-induced renal injury by reducing neutrophil activation. Male wistar rats were intravenously administered JTE-607 (JTE group, 30 mg/kg) or 5% mannitol (control group) 30 min before ischemia. JTE-607 reduced the I/R-induced increases in the serum concentrations of blood urea nitrogen and creatinine, and improved the histopathologic changes, including acute tubular necrosis. I/R-induced an increase in neutrophil activation, reflected by increases in renal cytokine-induced neutrophil chemoattractant (CINC)-1 and myeloperoxidase (MPO) concentrations which were significantly reduced by JTE-607. These findings indicate that JTE-607 attenuates I/R-induced acute renal injury, probably by inhibiting neutrophil activation. JTE-607 might be a novel therapeutic strategy for the protection of postoperative renal failure in surgery associated with renal ischemia as well as renal transplantation. 相似文献
86.
Restraint Method for Overcoming Heating Irregularity and Improving Heating Equipment Efficiency for Beverage Cans Using High‐Frequency Induction Heating
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Kenji Amei Tomohiro Yamamoto Takahisa Ohji Masaaki Sakui 《Electrical Engineering in Japan》2015,192(2):22-30
We were able to reduce heating irregularities in equipment for heating beverage cans by using the high‐frequency induction heating method and determining the resulting improvement in the heating efficiency. The heating irregularity between the top and bottom of the can was reduced to less than 3°C by improving the arrangement of the heating coils for the beverage can by thinning the winding and changing the circuit configuration. The efficiency of power conversion was improved from 93.0% to 97.4%. In this paper, the configuration of the equipment and the experimental results are reported. 相似文献
87.
A new tool has been developed to evaluate the reliability of assembly shop operation. It is a subsystem of AREM (Assembly Reliability Evaluation Method) [1] that can evaluate assembly fault occurrence rates by using product design information. This new tool uses approximately forty questions to assess quantitatively the influence of assembly shop operation reliability on assembly fault occurrence. This method is being used both to improve shop operation reliability and to select preferable shop, and is proven to be effective. The entire AREM system supports efficiently systematic improvement in assembly quality by examining both product design and assembly shop. 相似文献
88.
El-Sayed Mohamed Hanafy Naka Masaaki 《Journal of Materials Synthesis and Processing》1998,6(6):379-386
Diffusion couples of AlN/V were experimentally examined after annealing in a temperature range of 1373 K1773 K for a bonding time range of 0.9 ks21.6 ks. The interfacial reaction, reaction mechanism, and bond strength of the bonded AlN/V couples have been explained on the basis of phase relations at different bonding conditions, making use of elemental analysis, XRD, and shear testing method. Formation of V(Al) solid solution and V2N nitride controls the interfacial joining of the AlN/V couples. A complete diffusion path between AlN and V could be predicted at 1573 K before 0.9 ks, following a sequence of AlN/V(Al)/V2N/V. This sequence can be discussed during the Al-V-N ternary phase diagram. At a high temperature of 1573 K, AlN decomposition at the interface took place. A maximum bond strength could be obtained for a joint bonded at 1573 K after 5.4 ks, having a structure of AlN/V(Al)/V2N + V. 相似文献
89.
Tiered Electron Anions in Multiple Voids of LaScSi and Their Applications to Ammonia Synthesis
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Jiazhen Wu Yutong Gong Takeshi Inoshita Daniel C. Fredrickson Junjie Wang Yangfan Lu Masaaki Kitano Hideo Hosono 《Advanced materials (Deerfield Beach, Fla.)》2017,29(36)
Electrides—compounds in which electrons localized in interstitial spaces periodically serve as anions—have attracted broad attention for their exotic properties, such as extraordinary electron‐donating ability. In our efforts to expand this small family of phases, LaScSi emerges as a promising candidate. Its electron count is 2e? f.u.?1 in excess of that expected from the Zintl concept, while its structure offers interstitial spaces that can accommodate these extra electrons. Herein, this potential is explored through density functional theory (DFT) calculations and property measurements on LaScSi. DFT calculations (validated by heat capacity and electrical transport measurements) reveal electron density peaks at two symmetry‐distinct interstitial sites. Importantly, this electride‐like character is combined with chemical stability in air and water, an advantage for catalysis. Ru‐loaded LaScSi shows outstanding catalytic activity for ammonia synthesis, with a turnover frequency (0.1 s?1 at 0.1 MPa, 400 °C) an order of magnitude higher than those of oxide‐based Ru catalysts, e.g., Ru/MgO. As with other electrides, LaScSi's ability to reversibly store hydrogen prevents the hydrogen poisoning of Ru surfaces. The better performance of LaScSi, however, hints at the importance of the high concentration (>1.6 × 1022 cm?3) and tiered nature of its anionic electrons, which offers guidance toward new catalysts. 相似文献
90.
Fujio Abe Toshio Ohba Hideko Miyazaki Yoshiaki Toda Masaaki Tabuchi 《Materials at High Temperatures》2019,36(4):368-378
The effect of W-Mo balance and boron nitrides (BN) on creep rupture ductility has been investigated for five heats of 9% Cr steel with 1.5% Mo equivalent, 0.003% boron and 0.05% nitrogen at 600oC, 650oC and 700oC. The maximum time to rupture was 68,718 h at 650oC. The reduction of area (RA) slightly decreases for up to about 8000 and 1000 h at 600 and 650oC, respectively, while it significantly decreases above those. The BN particles are responsible for the degradation in RA at low stresses and long times by accelerating the formation of creep voids. At high stresses and short times, the RA decreases with increasing time to rupture and with increasing W concentration and concomitantly with decreasing Mo concentration. The rupture ductility is evaluated by using a semi-logarithmic diagram of the RA and total elongation, showing the necking dominant and void swelling dominant regions. 相似文献