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Es wird eine radiometrische Bandwaage zur Koksaustragsmengen-Messung in BHT-Kokereien beschrieben. Voranstellend werden einige analytische Ausdrücke zur theoretischen Behandlung dieses Bandwaagentyps mitgeteilt. Die Waage zeichnet sich durch hohe Stabilität der Anzeige, durch die Möglichkeit des routinemäßigen Umsetzens von Meßstelle zu Meßstelle innerhalb kurzer Zeit und durch einen relativ kleinen Wägefehler (Meßunsicherheit ≦ 2,9%) aus. Die Signalaufbereitung innerhalb der Elektronik erfolgt durchgängig digital unter Verwendung eines Rechnerschaltkreises.  相似文献   
3.
This paper reviews ways in which radioactive tracer techniques can he used to improve the efficiency of a caprolactam production plant, Residence time spectra and material distributions in different parts of the plant were measured by application of sodium 24, bromine 82 and technetium 99m. The investigations led to improved cumeneoxidators and gave useful informations on the catalytic decomposition of the phenolic tar and the hydrogenation process of phenol. It could he shown that the construction of the lactam extractor must he varied and the results of the tracerexperiments made in the distillation unit contributed to a higher quality of the final product.  相似文献   
4.
In the present study, we treat the stochastic homogeneous Gompertz diffusion process (SHGDP) by the approach of the Kolmogorov equation. Firstly, using a transformation in diffusion processes, we show that the probability transition density function of this process has a lognormal time‐dependent distribution, from which the trend and conditional trend functions and the stationary distribution are obtained. Second, the maximum likelihood approach is adapted to the problem of parameters estimation in the drift and the diffusion coefficient using discrete sampling of the process, then the approximated asymptotic confidence intervals of the parameter are obtained. Later, we obtain the corresponding inference of the stochastic homogeneous lognormal diffusion process as limit from the inference of SHGDP when the deceleration factor tends to zero. A statistical methodology, based on the above results, is proposed for trend analysis. Such a methodology is applied to modelling and forecasting vehicle stocks. Finally, an application is given to illustrate the methodology presented using real data, concretely the total vehicle stocks in Spain. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
5.
The first passage time (FPT) problem is an important problem with a wide range of applications in science, engineering, economics, and industry. Mathematically, such a problem can be reduced to estimating the probability of a stochastic process first to reach a boundary level. In most important applications in the financial industry, the FPT problem does not have an analytical solution and the development of efficient numerical methods becomes the only practical avenue for its solution. Most of our examples in this contribution are centered around the evaluation of default correlations in credit risk analysis, where we are concerned with the joint defaults of several correlated firms, the task that is reducible to a FPT problem. This task represents a great challenge for jump‐diffusion processes (JDP). In this contribution, we develop further our previous fast Monte Carlo method in the case of multivariate (and correlated) JDP. This generalization allows us, among other things, to evaluate the default events of several correlated assets based on a set of empirical data. The developed technique is an efficient tool for a number of financial, economic, and business applications, such as credit analysis, barrier option pricing, macroeconomic dynamics, and the evaluation of risk, as well as for a number of other areas of applications in science and engineering, where the FPT problem arises. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
6.
Application of hydrocolloids as baking improvers   总被引:1,自引:0,他引:1  
Hydrocolloids (or gums) belong to a group of biopolymers widely used in food technology. In the bakery industry, these compounds help to improve food texture and moisture retention, to retard starch retrogradation, and, finally, to enlarge the overall quality of the products during storage. Since recently, some hydrocolloids are being used due to their polymeric structure as fat replacers to obtain low calorie products and to substitute gluten in the formulation of gluten-free breads. This study describes the applications of some hydrocolloids in the bakery industry. Technological effects of these substances for different types of bakery products are also discussed.  相似文献   
7.
A novel protocol for all‐atom RNA tertiary structure prediction is presented that uses restrained molecular mechanics and simulated annealing. The restraints are from secondary structure, covariation analysis, coaxial stacking predictions for helices in junctions, and, when available, cross‐linking data. Results are demonstrated on the Alu domain of the mammalian signal recognition particle RNA, the Saccharomyces cerevisiae phenylalanine tRNA, the hammerhead ribozyme, the hepatitis C virus internal ribosomal entry site, and the P4–P6 domain of the Tetrahymena thermophila group I intron. The predicted structure is selected from a pool of decoy structures with a score that maximizes radius of gyration and base–base contacts, which was empirically found to select higher quality decoys. This simple ab initio approach is sufficient to make good predictions of the structure of RNAs compared to current crystal structures using both root mean square deviation and the accuracy of base–base contacts. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011  相似文献   
8.
There is an increasing demand for quantitative data on metabolite exposure triggered by regulatory guidances. This contribution describes the accuracy of nanoelectrospray ionization mass spectrometry response of drug compounds and their metabolites from biological matrices compared with radiometric quantification. This is a comprehensive investigation of a set of real-life pharmaceutical compounds in relevant matrices such as urine, bile, feces and plasma. The data suggest that nanoelectrospray mass spectrometry can be used for semi-quantitation of metabolites in the absence of reference standards. Therefore, this approach is suitable to screen out non-relevant metabolites early in development as long as an adequate analytical error margin is applied thus balancing risks and resources.  相似文献   
9.
王磊  刘静 《化学教育》2019,40(20):1-12
镓是第一个根据化学元素周期律预言并在自然界中证实的元素,是室温下电导率和热导率均为最大的液态物质,镓在电子工业中得到了广泛应用,被誉为电子工业“脊梁”。近十几年来,镓的更多应用潜力被发掘出来,在电子工业、散热、增材制造、柔性机器、生物医学等领域均有重要的应用前景。  相似文献   
10.
刘玉成  郑啸  黄培强 《化学学报》2019,77(9):850-855
通过氮α-位碳自由基构造氮α-位碳-碳键是合成含氮有机化合物的重要方法. 近期, 利用可见光催化氧化芳香叔胺—氮α-位去质子化形成氮α-位碳自由基的原理发展了一系列新颖的自由基加成(偶联)反应, 成为氮α-位碳自由基化学发展的重要方向. 本文应用Ir-催化剂, 实现了光催化氧化还原体系中硝酮与芳香叔胺的自由基偶联反应, 高效地合成β-氨基羟胺化合物. 该反应条件温和、操作简单, 具有较高的原子经济性, 且对于各种链状、环状以及手性硝酮都具有良好的适用性, 产物可方便地转化为重要的邻二胺化合物.  相似文献   
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