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11.
Shi-Rong Tang Zhi-Min Zong Lei Zhou Wei Zhao Xiao-Bo Li Yao-Li Peng Rui-Lun Xie Xiao-Fei Chen Wen-Tao Gu Xian-Yong Wei 《Renewable Energy》2010,35(5):946-951
Cornstalk was depolymerized in supercritical methanol and ethanol, respectively. The depolymerization products were analyzed with FTIR and GC/MS. The results show that the products can be classified into methyl esters and dimethyl diesters, ethyl esters and diethyl phthalate, hydroxybenzenes and dihydroxybenzenes, ketones, methoxybenzene to trimethyoxybenzenes, hydrocarbons, nitrogen-containing organic compounds and other compounds. Most of the products are oxygen-containing species. Palmitate and octadec-9-enoate are the two most abundant products both with supercritical methanol and with supercritical ethanol. The fact that the cornstalk depolymerization in different solvents afforded many different products suggests that the two solvents played different roles in the cornstalk depolymerization. 相似文献
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This work demonstrates high-performance and current crowding-free InGaN/GaN light-emitting diodes (LEDs) using an electrically-reverse-connected Schottky diode (SD) and an Mg-delta (δ) doped layer.Poss... 相似文献
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Dao-Jun Guo Xin-Ping Qiu Wen-Tao Zhu Li-Quan Chen 《Applied catalysis. B, Environmental》2009,89(3-4):597-601
Sulfated zirconia supported on multi-walled carbon nanotubes as new supports of Pt catalyst (Pt–S-ZrO2/MWCNT) was synthesized with aims to enhance electron and proton conductivity and also catalytic activity of Pt electrocatalyst in terms of larger concentrations of ionizable OH groups on surfaces. Fourier transform infrared spectroscopy analysis shows that the sample surfaces were modified with sulfate. Transmission electron microscopy results show that the Pt and sulfated ZrO2 particles dispersed relatively uniformly on the surface of the multi-walled carbon nanotube. X-ray diffraction shows that S-ZrO2 and Pt coexist in the Pt–S-ZrO2/MWCNT composites and S-ZrO2 has no effect on the crystalline lattice of Pt. Pt–S-ZrO2/MWCNT catalyst was evaluated in terms of the electrochemical activity for methanol electro-oxidation using cyclic voltammetry, steady-state polarization experiments and electrochemical impedance spectroscopy technique at room temperature. Pt–S-ZrO2/MWCNT catalyst show higher catalytic activity for methanol electro-oxidation compared with Pt catalyst on non-sulfated ZrO2/MWCNT support and commercial Pt/C (E-TEK). 相似文献
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在有限时间热力学理论的基础上,对双声源驱动热声制冷机的回热器声场进行分析,以特征时间为特征参数来表征热声系统的换能效应,寻求特征时间与回热器熵产之间的最优关系以及其他因素对熵产率的影响. 结果表明:熵产率随着特征时间的减少,到达一个极小点后再平缓增大,通过调节阻抗比,寻求到一个最佳阻抗比值所对应的最小熵产率, 存在一个最优特征时间使得系统的不可逆熵产最小,此时不可逆能量损失最小,有效的提高了双声源驱动热声制冷机效率,有利于双声源驱动系统运行. 相似文献
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文中提出了一种基于响应面法的电永磁吸盘充退磁吸力及材料使用量的多目标优化方法。该方法选取电永磁吸盘结构的部分关键参数作为设计变量建立响应面模型,并采用目标驱动优化设计产生候选点,最后选出符合预期目标的设计变量参数。通过该方法优化后的电永磁吸盘,在充磁工作状态下的吸附力提升了35.7%,退磁卸载状态下的残余吸力减小了92%,工作性能得到了显著提升,同时优化了材料的使用量,提高了产品的费效比。 相似文献
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Cheng-Bin Shi Wen-Tao Yu Hao Wang Jing Li Min Jiang 《Metallurgical and Materials Transactions B》2017,48(1):146-161
Calcium modification of both alumina and MgO·Al2O3 inclusions during protective gas electroslag remelting (P-ESR) of 8Cr17MoV stainless steel and its effect on nitrides and primary carbides were studied by analyzing the transient evolution of oxide and sulfide inclusions in the P-ESR process. The oxide inclusions that were not removed during P-ESR without calcium treatment were found to retain their original state until in as-cast ingot. Calcium treatment modified all MgO·Al2O3 and alumina inclusions that had not been removed in the P-ESR process to liquid/partially liquid CaO-Al2O3-(MgO) with uniformly distributed elements, in addition to a small proportion of partially modified inclusions of a CaO-MgO-Al2O3 core surrounded by a liquid CaO-Al2O3. The modification of low-MgO-containing MgO·Al2O3 inclusions involves the preferential reduction of MgO from the MgO·Al2O3 inclusion by calcium and the reaction of calcium with Al2O3 in the inclusion. It is the incomplete/complete reduction of MgO from the spinel by calcium that contributes to the modification of spinels. Alumina inclusions were liquefied by direct reaction with calcium. Calcium treatment during P-ESR refining also provided an effective approach to prevent the formation of nitrides and primary carbides in stainless steel through modifying their preferred nucleation sites (alumina and MgO·Al2O3 inclusions) to calcium aluminates, which made no contribution to improving the steel cleanliness. 相似文献