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71.
Hsin Chu Yiing-Yuan Chiou Kuen-How Horng Ting-Ke Tseng 《Canadian Metallurgical Quarterly》2001,127(5):438-442
Catalytic incineration is one of the cost-effective technologies to solve troublesome volatile organic compounds. However, some sulfur containing volatile organic compounds, such as ethyl mercaptan, may deactivate the Pt catalyst that is commonly used in the catalytic incineration process. This paper provides information on the poisoning effect of ethyl mercaptan. The catalytic incineration of ethyl mercaptan, typically emitted from the petrochemical industry, over a Pt/Al2O3 fixed-bed catalytic reactor was studied. The effects of operating parameters including inlet temperature, space velocity, C2H5SH concentration, O2 concentration, and catalyst size were characterized. Catalytic incineration on a mixture of C2H5SH with CH3SH was also tested. The results show that the conversions of C2H5SH increase as the inlet temperature increases and the space velocity decreases. For the temperature from 200–260°C, the higher the C2H5SH concentration is, the lower its conversion. The O2 concentration has a positive effect on the conversion of C2H5SH. C2H5SH has a poisoning effect on the Pt/Al2O3 catalyst, especially at lower temperature. The existence of CH3SH has no effects on the conversion of C2H5SH. 相似文献
72.
Silicon carbide whisker-reinforced aluminium was fabricated by vacuum infiltration of liquid aluminium into a porous whisker
preform under an argon gas pressure, using an infiltration temperature of 665 °C. The volume fraction of whiskers ranged from
11% to 37%. No whisker pull-out was observed on the fracture surface for an infiltration temperature of 665 °C, but some whisker
pull-out was observed for an infiltration temperature of 720 °C. Both the tensile strength and ductility decreased with increasing
infiltration temperature above 665 °C. Tensile test results from room temperature to 300 °C are reported. They showed that
the quality of these composites was comparable to that of composites made by powder metallurgy or squeeze casting. The coefficient
of thermal expansion at 100–150 °C was decreased by 45% by the addition of 37 vol % whiskers. 相似文献
73.
采用向量式有限元分析,对受火钢结构的非线性响应进行研究。通过与已公布的钢结构试验数据及分析结果相比较,验证数字模型。对Williamstoggle框架和钢框架在地震荷载和火荷载下的非线性性能响应进行研究。数值结果显示:当温度低于临界值时,随着温度增加,Williamstoggle框架的承载力显著增大;然而,当温度高于临界值时,随着温度增加,Williamstoggle框架的承载力显著减少,但当温度达到1000℃时,承载力仍大于室内温度时的弹性屈服强度。此外,随着温度增加,屈服前浅拱向上偏转,而且其挠度远小于同样跨度的梁结构。屈曲后,结构的挠度向下,当重新平衡时,显示出悬链线作用。在地震诱发的火灾中,结构变形受余震、火、结构单元的破坏影响较大。 相似文献
74.
75.
Oil sensitivity and its asymmetric impact on the stock market 总被引:1,自引:0,他引:1
We develop a two-step methodology to facilitate an examination of the impact of oil shocks on stock returns. Oil price volatility is monitored in this study through the use of a regime-switching model, with the presence of jumps subsequently being taken into consideration to examine the asymmetric effects of oil prices on stock returns. Our analysis provides quite conclusive results based upon the use of a regime-switching model with consideration of jumps; that is, when there are significant fluctuations in oil prices (West Texas Intermediate; WTI), the resultant unexpected asymmetric price changes lead to negative impacts on S&P 500 returns. However, the same result does not hold in a regime of lower oil price fluctuations. We therefore suggest that the achievement of a well diversified portfolio should involve the consideration of oil price shocks, which, as a consequence, should also help to improve the accuracy of hedging against oil price risks. 相似文献
76.
77.
Jong-Yee Chiou Ping-Yao Wu Chin-Chin Tsai Ta-Jo Liu 《Polymer Engineering and Science》1998,38(1):49-59
An integrated numerical approach is proposed to simulate the polymeric liquid flow in a bicomponent coextrusion die with a feedblock inlet system. The three-dimensional finite element method is applied to determine the fluid motion and the interfacial position of the two polymeric liquids before entering the die body, whereas the two-dimensional Hele-Shaw model is assumed to be applicable for fluid flow in the manifold and the slot section of the die body. An optimal design procedure is incorporated into the simulation and the dimensions of the manifold can be properly selected such that the die can deliver the composite liquid film with acceptable uniformity. A specially designed choker bar can also be inserted to reduce the flow non-uniformities caused by production variations. The contraction of the composite liquid film emanating from the die exit is also predicted under different draw ratios. 相似文献
78.
Bor‐Sen Chiou Haani Jafri Trung Cao George H. Robertson Kay S. Gregorski Syed H. Imam Greg M. Glenn William J. Orts 《应用聚合物科学杂志》2013,129(6):3192-3197
Wheat gluten was reacted with citric acid to produce natural superabsorbent materials able to absorb up to 78 times its weight in water. The properties of the modified gluten samples were characterized using Fourier Transform Infra‐red (FTIR) spectroscopy, thermogravimetric analysis, and water uptake. The reaction between gluten and citric acid was examined for gluten : citric acid ratios of 0.38 : 1 to 0.75 : 1 at temperatures from 100 to 130°C. More citric acid reacted for samples containing higher citric acid concentrations and at higher temperatures. FTIR analyses indicated the presence of carboxylate groups on the modified gluten samples, which resulted in modified samples having higher water uptake values than neat gluten. The sample with a gluten:citric acid ratio of 0.5 : 1 and reaction temperature of 120°C had the largest water uptake value. Also, all modified gluten samples had lower thermal stability than neat gluten. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
79.
Vincent Yi-Fong Su Shih-Hwa Chiou Wei-Chih Chen Wen-Kuang Yu Huai-Hsuan Wu Hao Chen Kuang-Yao Yang 《International journal of molecular sciences》2021,22(11)
The conditioned medium of induced pluripotent stem cells (iPSC-CM) can attenuate neutrophil recruitment and endothelial leakage of lipopolysaccharide (LPS)-induced acute lung injury (ALI). Therefore, we investigated the mechanisms by which iPSC-CM regulate the interaction between neutrophils and the endothelium in ALI. Murine iPSCs (miPSCs) were delivered intravenously to male C57BL/6 mice (8–12 weeks old) 4 h after intratracheal LPS injection. A miPSC-derived conditioned medium (miPSC-CM) was delivered intravenously to mice after intratracheal LPS injection. DMSO-induced HL-60 cells (D-HL-60, neutrophil-like cells) and human umbilical vein endothelial cells (HUVECs) were used as in vitro models to assess the interaction of neutrophils and endothelial cells. miPSC-CM diminished the histopathological changes in the lungs and the neutrophil count in bronchoalveolar lavage fluids of ALI mice. miPSC-CM attenuated the expression of adhesion molecules in the lungs of ALI mice. Human iPSC conditioned medium (hiPSC-CM) reduced the expression of adhesion molecules in a HUVEC and D-HL-60 co-culture after LPS stimulation, which decreased the transendothelial migration (TEM) of D-HL-60. A human angiogenesis factors protein array revealed that leukemia inhibitory factor (LIF) was not detected in the absence of D-HL-60 and hiPSC-CM groups. hiPSC-CM significantly promoted the production of endogenous LIF in in vitro models. Administration of an anti-LIF antibody not only reversed the effect of iPSC-CM in ALI mice, but also blocked the effect of iPSC-CM on neutrophils TEM in in vitro models. However, a controlled IgG had no such effect. Our study demonstrated that iPSC-CM promoted endogenous LIF to inhibit neutrophils TEM and attenuate the severity of sepsis-induced ALI. 相似文献
80.
Pd1Pt3, Pd1Pt1, and Pd3Pt1 nanoparticles supported on multi-wall carbon nanotubes (CNTs) were prepared by the self-regulation reduction of sodium n-dodecyl sulphate and used as catalysts in oxygen reduction reactions (ORRs). The crystal properties of these alloy nanoparticles on the CNT were measured by X-ray diffraction spectroscopy (XRD) and high-resolution transmission electron microscopy (HRTEM). The angle shifting of the XRD peak and the lattice spacing of the nanoparticles measured by HRTEM increased with an increase in Pd amount, indicating a regulable Pd-Pt ratio for the alloy nanoparticle composition. Rotating ring-disk electrode (RRDE) measurements indicate that the number of electrons catalysed by the Pd1Pt3/CNT, Pd1Pt1/CNT, and Pd3Pt1/CNT nanocatalysts in the ORRs were 3.98, 3.97, and 3.93, respectively. These results show that these ORRs occur via a 4-electron pathway. Linearly scanned voltammetry in the electrolyte with methanol revealed that Pd3Pt1/CNT has high methanol tolerance during ORRs. 相似文献