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71.
研究了用固体碱 KOH/Al_2O_3催化合成苯叉丙酮,确定了合成的最佳工艺条件:n(苯甲醛)∶n(丙酮)=1∶4.催化剂用量2g,催化剂最佳负载量12mmol/g,反应温度40~45℃,反应时间为3h,产率达88%以上。  相似文献   
72.
BACKGROUND: The application of lipase‐rich enzyme pools (such as the crude solid enzymatic preparation (SEP) obtained from Penicillium restrictum solid‐state fermentation of agro‐industrial wastes) to activated sludge systems may be an effective strategy for preventing various operational problems. The continuous addition of SEP to the treatment system can become cost‐prohibitive when in situ production and/or storage are factored in. The application of SEP to high‐fat wastewater treatment would only be justified as an emergency measure, such as a sudden increase in the fat content of the bioreactor influent. Therefore, the primary objective of this work was to investigate the efficiency of a crude SEP during fat shock loads, simulated through the periodic addition of dairy industry waste containing high fat concentrations to the feed stock of an activated sludge system, operated in continuous mode. RESULTS: The test bioreactor exhibited a higher average chemical oxygen demand (COD) removal efficiency than the control bioreactor (83% for control and 90% for test) and the fat accumulation in the biological flocs of the test bioreactor was 3.2 times lower than that in the control bioreactor. Turbidity was also lower in the effluent of the test bioreactor (123 and 66 FTU in control and test, respectively) and it had a shorter recovery time between shock loads, especially when the interval between loads was shorter than one month (biweekly and weekly shock loads). CONCLUSION: The addition of SEP during fat overloads in the reactor feed maintained efficient COD removal in the test bioreactor for 270 days without any operational problems. Copyright © 2008 Society of Chemical Industry  相似文献   
73.
离子束辅助沉积制备高功率激光薄膜的研究   总被引:4,自引:0,他引:4       下载免费PDF全文
综述了离子束辅助沉积技术在高功率激光薄膜制备中的应用研究进展.指出该技术在制备高激光损伤阈值的薄膜中存在的问题,即出现过高的堆积密度,会给薄膜带来杂质缺陷、化学计量比缺陷、损伤缺陷、晶界缺陷,制备薄膜的残余应力存在着压应力增加的趋势,会改变薄膜的晶体结构等.并指出了该研究领域的研究方向.  相似文献   
74.
p-Si薄膜生长的ECR-CVD等离子体系统的结构设计   总被引:1,自引:1,他引:0  
提出了一种生长p-Si薄膜的ECR-PECVD等离子体系统。系统采用永磁铁和线圈相结合,改善反应室磁场的均匀性;微波窗口设计成多层结构.避免窗口污染;衬底托架移动和旋转利于改善生长膜的均匀性。  相似文献   
75.
The principle of maximum informational entropy is used to find the probability density function for the departure radius of a bubble in boiling on a solid surface. A general relation is derived, which leads to particular expressions.  相似文献   
76.
An always increasing knowledge on material properties as well as a progressively more sophisticated production technology make shape memory alloys (SMA) extremely interesting for the industrial world. At the same time, SMA devices are typically characterized by complex multi‐axial stress states as well as non‐homogeneous and non‐isothermal conditions both in space and time. This aspect suggests the finite element method as a useful tool to help and improve application design and realization. With this aim, we focus on a three‐dimensional macroscopic thermo‐mechanical model able to reproduce the most significant SMA features (Int. J. Numer. Methods Eng. 2002; 55 : 1255–1264), proposing a simple modification of such a model. However, the suggested modification allows the development of a time‐discrete solution algorithm, which is more effective and robust than the one previously discussed in the literature. We verify the computational tool ability to simulate realistic mechanical boundary value problems with prescribed temperature dependence, studying three SMA applications: a spring actuator, a self‐expanding stent, a coupling device for vacuum tightness. The effectiveness of the model to solve thermo‐mechanical coupled problems will be discussed in a forthcoming work. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
77.
Review on testers for measuring flow properties of bulk solids   总被引:3,自引:2,他引:1  
 The author was asked by the International Fine Particle Research Institue (IFPRI) to write a critical review on shear testers for IFPRI-members. The review was delivered to IFPRI in summer 1999. Following the contract with IFPRI it was not allowed to publish the review elsewhere for at least two years. Granular Matter invited the author to submit the review in the original form; during the refereeing process (besides other changes) it turned out that some remarks should be added here for clarification: - Since 1999, the author is not aware of a really new device for testing bulk solid properties, which could lead to a change of the general comments and conclusions provided in the review. It was argued, that the review is referring too much to the work of Jenike, while the works of Johanson and Peschl were not adequately cited. Both are excellent engineers with a lot of experience, but their basic ideas are not available in published form, and if, they are not set in relation to alternative approaches so that an objective comparison in detail would be a future research issue rather than a topic in this report. A discussion on the influence of electrostatic charges was missing. There hardly is an influence, since the particles are in continuous contact. Only with non-conducting plastic particles electrostatic charges could cause problems. But no relevant experiments and results are known. In closed systems, the effect of electric charges is thus mainly neglected, but it is clear that electrostatic forces are eminent in flows with a free surface – an issue not addressed in this review. Received: 1 November 2002  相似文献   
78.
在脂肪酸分子中引入硼和氮,合成了一种环境友好水基润滑添加剂BNR,并利用红外光谱对其主要官能团进行了表征。通过四球试验机考察了BNR添加剂在水中的抗磨性能与极压性能,用X射线光电子能谱仪对磨痕表面元素进行了分析,探讨了该类添加剂的极压抗磨作用机理。结果表明:硼氮化水基润滑添加剂BNR在水中具有优良的抗磨和减摩性能;其润滑作用机理是由于长链脂肪酸分子的载体作用、硼的缺电子性、氮的高反应活性以及三者的协同作用与摩擦金属表面形成了一层高强度的吸附膜和/或摩擦化学反应膜。  相似文献   
79.
钻井液固相化学清洁剂ZSC-201的合成及性能   总被引:6,自引:0,他引:6  
介绍了钻井液用固相化学清洁剂ZSC-201的室内合成及性能评价,结果表明,固相化学清洁剂ZSC-201具有较强的抑制性,可有效抑制粘土水化分散,保证钻井液清洁,在钻井液体系中与阴、阳离子型钻井液处理剂配伍性好,同时具有较好的抑制增效作用,在有效的加量内对钻井液滤矢量和流变性等影响小,固相化学清洁剂ZSC-201已在中原油田近30口井中应用,具有良好的推广应用前景。  相似文献   
80.
研究了用真空蒸发法在玻璃衬底上制备稀土掺杂纳米ZnO薄膜结构、导电性及光透射性能。结果显示 ,在 5 0 0℃氧化、热处理稀土元素Nd掺杂后能够明显改善纳米ZnO薄膜的结构特性 ,薄膜的晶粒尺寸随掺杂含量的增加而减小。掺Nd使ZnO薄膜的电性能有所改善但使纳米ZnO薄膜的光透射性有所降低。  相似文献   
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