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51.
高碘酸钾法测钢铁及合金中锰的改进建议 总被引:1,自引:0,他引:1
张萍 《理化检验(化学分册)》1999,(11)
试样经酸溶解后,以磷酸-高氯酸混合酸(4 1)或(9 1)氧化至冒烟.在硫酸、磷酸介质中,用高碘酸钾将锰氧化到七价,测其吸光度. 相似文献
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Samples from a high-dimensional first-order auto-regressive process generated by an independently and identically distributed random innovation sequence are observed by a sender which can communicate only finitely many bits per unit time to a receiver. The receiver seeks to form an estimate of the process value at every time instant in real-time. We consider a time-slotted communication model in a slow-sampling regime where multiple communication slots occur between two sampling instants. We propose a successive update scheme which uses communication between sampling instants to refine estimates of the latest sample and study the following question: Is it better to collect communication of multiple slots to send better refined estimates, making the receiver wait more for every refinement, or to be fast but loose and send new information in every communication opportunity? We show that the fast but loose successive update scheme with ideal spherical codes is universally optimal asymptotically for a large dimension. However, most practical quantization codes for fixed dimensions do not meet the ideal performance required for this optimality, and they typically will have a bias in the form of a fixed additive error. Interestingly, our analysis shows that the fast but loose scheme is not an optimal choice in the presence of such errors, and a judiciously chosen frequency of updates outperforms it. 相似文献
54.
利用密度泛函理论和弹性散射格林函数方法,对硫醇分子膜的电学特性进行了理论模拟,计算结果表明,分子结的导电能力随着压力增加而增加,对单分子构成的分子结来说,电流的增加主要是由于电极距离的变化导致单个分子与电极的耦合增强,对于由多个分子构成的分子膜来说,由于外加压力的变化,导致分子结的链内隧穿和链间隧穿几率增大,从而导致导... 相似文献
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YUAN ChunXue XIN Qian LIU HuiJun WANG Lei JIANG MinHua & TAO XuTang State Key Laboratory of Crystal Materials Sh ong University Jinan China 《中国科学B辑(英文版)》2011,(4)
Trger's base (TB) is a well-known chiral molecule with rigid concave shape that makes it applicable in different areas such as superamolecular chemistry,molecular recognition,biological labeling,and so on.In this article,we briefly summarize some recent research progress in the optoelectronic properties of novel TB analogues and their applications in optoelectronic field with emphasis on the developments achieved in our group. 相似文献
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Xi Rong HUANG * Yue Zhong LI Guo Liang YANG Li Li LIU Yin Bo QU Wen Juan ZHANG State Key Lab of Microbial Technology of China Shandong University Jinan Key Lab for Colloid Inferface Chemistry of the Education Ministry of Chin 《中国化学快报》2001,(5)
Lipase is one of the hydrolases. It catalyzes the hydrolysis of triglycerides, liberating fat acids. Based on its catalysis and the response of a glass electrode to the acids, a glass-electrode-based lipase sensor can be fabricated1, which has great potential in clinical medicine for the detection of blood fat in human serum samples.The immobilization of lipase on the bulb of a glass electrode is the key to the development of the sensor. In addition to its response time, which has a lot to do … 相似文献
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本文报道一种新的测定δ-氨基乙酰丙烯(δ-ALA)的分光光度法,方法基于δ-ALA被缩合成吡咯衍生物后,在酸性条件与Fe^3+生成橙红色配合物,其λmax为480nm,ε为6.6×10^3L.mol^-1.cm^-1,线性范围10~400μg/25mL,回收率94~104%。 相似文献
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孙文涛 《高等学校计算数学学报(英文版)》1997,(1)
Two-phase, immiscible, incompressible flow in porous media is governed by a system of nonlinear partial differential equations. In most practical applications convection physically dominates diffusion, and the object of this paper is to develop a finite difference method combined with the method of characteristics and the lumped mass method to treat the parabolic equation of the differential system. This method is shown satisfy the maximum principle and its error analysis is presented. 相似文献