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排序方式: 共有3737条查询结果,搜索用时 15 毫秒
131.
Won Seok Kim Dae Ryook Yang Dong Ju Moon Byoung Sung Ahn 《Chemical Engineering Research and Design》2014
A process for methanol production from 100 MM scfd of stranded gas and CO2 is proposed and simulated using a commercial process simulator, PRO/II v.9.1, for a FPSO (floating production, storage, off-loading) system. The process consists of Steam-CO2 Reforming (SCR), methanol synthesis, a Reverse Water-Gas Shift (RWGS) reaction and ancillaries with recycle streams to SCR and RWGS. All reactors were simulated using the Gibbs reactor model. Also, the Plug Flow Reactor (PFR) model with reaction rate equations was used for the methanol reactor and the result was compared to the Gibbs reactor model. To maximize the use of the carbon source in stranded gas and CO2 while avoiding an undesirable increase in process size, the optimum recycle ratios were calculated with a satisfying constraint, a steam-to-carbon ratio ≥ 1 in the SCR. In the proposed Methanol-FPSO process the RWGS reactor can maximize CO2 utilization and case studies were performed to analyze the influence of RWGS. 相似文献
132.
By Joseph Y. Lee Jinyong Ahn JeGwang Yoo Joonsung Kim Hwa-Sun Park Shuichi Okabe 《电子工业专用设备》2007,36(5):40-50
在20世纪90年代,球栅阵列封装(BGA)和芯片尺寸封装(CSP)在封装材料和加工工艺方面达到了极限。这2种技术如同20世纪80年代的表面安装器件(SMD)和70年代通孔安装器件(THD)一样,在电学、机械、热性能、尺寸、质量和可靠性方面达到最大值。目前,三维封装正在成为用于未来采用的先进印制板(PCB)制造工艺的下一个阶段。它们可以分为圆片级封装、芯片级封装、和封装面。叠层封装(PoP)是一种封装面叠层封装类型的三维封装技术[15]。 相似文献
133.
Kyung Rae Ko Hyunil Lee Soo-Hong Han Wooyeol Ahn Do Kyung Kim Il-Su Kim Bo Sung Jung Soonchul Lee 《International journal of molecular sciences》2022,23(5)
A large number of studies have focused on the role of substance P (SP) and the neurokinin-1 receptor (NK1R) in the pathogenesis of a variety of medical conditions. This review provides an overview of the role of the SP-NK1R pathway in the pathogenesis of musculoskeletal disorders and the evidence for its role as a therapeutic target for these disorders, which are major public health problems in most countries. To summarize, the brief involvement of SP may affect tendon healing in an acute injury setting. SP combined with an adequate conjugate can be a regenerative therapeutic option in osteoarthritis. The NK1R antagonist is a promising agent for tendinopathy, rheumatoid arthritis, and osteoarthritis. Research on the SP-NK1R pathway will be helpful for developing novel drugs for osteoporosis. 相似文献
134.
135.
H. Ahn C. Pfohl J. Whle A. Gebauer S. Biemer A. Bulak E. Menthe E. Rodriguez Cabeo T. Stucky A. Gebauer 《Materialwissenschaft und Werkstofftechnik》1996,27(12):573-583
Develpoment of wear and corrosion resistant surface systems In this study two methods are described to realize wear and corrosion resistant surface systems: Plasma diffusion treatment (PDT) and Plasma assited CVD (PACVD). Plasma nitriding, Plasma nitrocarburizing and plasma boriding are used to treat different kinds of substrates. The advances of PACVD and the development of low temperature PACVD and industrial applications of these techniques are explained. 相似文献
136.
Saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) show different effects on the development of insulin resistance.
In this study, we compared the effect of dietary SFA and MUFA on the insulin signaling pathway in the skeletal muscle of a
type 2 diabetic animal model. Twenty-nine-week-old male Otsuka Long-Evans Tokushima fatty (OLETF) rats were randomly divided
into three groups and fed one of the following diets for 3 weeks; a normal chow diet, an SFA (lard oil) enriched or a MUFA
(olive oil) enriched high-fat diet. The vastus lateralis muscle was used for analyses. Insulin tolerance test showed improved
insulin sensitivity in rats fed the MUFA diet, as compared to those fed the SFA diet (p < 0.001). The SFA diet reduced IRS-1 expression and phosphorylated PI3K levels in skeletal muscle, as compared with a chow
diet (p < 0.001, respectively). On the contrary, muscle IRS-2 expression and phosphorylated ERK1/2 was significantly increased in
rats fed the SFA diet (p < 0.001, respectively). Membrane translocation of glucose transporter type 4 decreased in the skeletal muscle of rats fed
the SFA diet, as compared to those fed a chow diet (p < 0.001). These changes in insulin signaling pathway in skeletal muscle were not observed in rats fed the MUFA diet. In conclusion,
the beneficial effect of dietary MUFA on insulin sensitivity is associated with a conserved IRS-1/PI3K insulin signaling pathway
which was altered by dietary SFA. 相似文献
137.
A thermodynamic investigation of adsorbate‐adsorbate interactions of carbon dioxide on nanostructured carbons 下载免费PDF全文
Maxwell Murialdo Channing C. Ahn Brent Fultz 《American Institute of Chemical Engineers》2018,64(3):1026-1033
A thermodynamic study of carbon dioxide adsorption on a zeolite‐templated carbon (ZTC), a superactivated carbon (MSC‐30), and an activated carbon (CNS‐201) was carried out at temperatures from 241 to 478 K and pressures up to 5.5?106 Pa. Excess adsorption isotherms were fitted with generalized Langmuir‐type equations, allowing the isosteric heats of adsorption and adsorbed‐phase heat capacities to be obtained as a function of absolute adsorption. On MSC‐30, a superactivated carbon, the isosteric heat of carbon dioxide adsorption increases with occupancy from 19 to 21 kJ?mol?1, before decreasing at high loading. This increase is attributed to attractive adsorbate–adsorbate intermolecular interactions as evidenced by the slope and magnitude of the increase in isosteric heat and the adsorbed‐phase heat capacities. An analysis of carbon dioxide adsorption on ZTC indicates a high degree of binding‐site homogeneity. A generalized Law of Corresponding States analysis indicates lower carbon dioxide adsorption than expected. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1026–1033, 2018 相似文献
138.
Grace Lee Chao Chen Seung-Tae Yang Wha-Seung Ahn 《Microporous and mesoporous materials》2010,127(1-2):152-156
Two different kinds of mesoporous alumina samples were prepared using aluminum tri-sec-butoxide in the presence of either cetyltrimethylammonium bromide (MA-1) or stearic acid (MA-2) as a structure-directing agent, and tested for adsorptive removal of fluoride in water. Both materials contain a wormhole-like mesopore structure, but exhibited different textural properties: surface area (421 or 650 m2/g) and pore volume (0.96 or 0.59 cm3/g). These mesoporous aluminas demonstrated significantly improved adsorption capacity and faster kinetics to those of the commercial activated aluminas in fluoride removal by adsorption process. MA-2 prepared using stearic acid, in particular, demonstrated an adsorption capacity (14.26 mg/g) and initial adsorption rate (14.6 mg/g min) that were respectively 2.2 and 45 times higher than those of a commercial gamma alumina. The textural features of larger surface area and relatively smaller pore size in MA-2 compared to the activated aluminas are believed to be responsible for this enhancement in adsorption process. 相似文献
139.
An alternative concept of an integrated water electrolysis/hydrogen-hydrogen fuel cell using metal electrocatalysts and a solid polymer electrolyte is described. Instead of operating both electrodes as hydrogen and oxygen electrodes respectively the electrodes are used as oxidation and reduction electrodes in both modes of operation. A more suitable selection of electrocatalysts and an improved cell design are possible; both can increase the efficiency of the cell considerably. New results on the electrocatalytic activity of various noble-metal containing catalysts with respect to both oxygen evolution and hydrogen oxidation in a proton exchange membrane-cell at 80°C are reported. Kinetic data derived from Tafel plots of the oxygen evolution polarization curves agree closely with those of experiments with aqueous sulphuric acid electrodes. This agreement allows the determination of kinetic parameters for electrocatalysts difficult to prepare in solid smooth electrodes but easy to be made into porous deposits. Polarization curves of the hydrogen oxidation reaction clearly indicate a relative activity rating of the studied catalysts. In cycling tests the lifetime stability of the new bifunctional oxidation electrode was determined. Polarization data obtained under these conditions agree with those obtained in earlier experiments where electrodes were exposed to only one type of oxidation reaction. During a test of 10 cycles (30 min of electrolyser and 30 min of fuel cell mode each) no changes in the electrode potential were observed. With the conventional cell design employing a hydrogen and an oxygen electrode both catalyzed with platinum and a current density of 100 mA cm–2 a storage efficiency of 50% was calculated; with the alternative concept of oxidation and reduction electrodes and selected oxidation catalysts this was improved to 57%. With further improvements these efficiencies seem possible even at current densities of 500 mA cm–2. 相似文献
140.
The evaluation of spot weldability is very important in managing the quality of products and also in increasing the credibility in the automotive manufacturing processes. The purpose of this study is to investigate the applicability of ultrasonic techniques for the evaluation of weldability in spot weldment. Through test results, it is confirmed that the behavior of the average attenuation coefficient (α avg) shows a close relationship with the behavior of tensile-shear strength. The transit time of the ultrasonic pulse echo and nugget size also show a close interrelation. If a larger experimental database with various welding conditions can he collected, then it can he shown that the attenuation coefficient and the transit time of an ultrasonic wave can be effective parameters in the evaluation of spot weldability. 相似文献