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241.
242.
非定常自由面流激波解的二阶守恒算法 总被引:1,自引:0,他引:1
蔡启富 《数学物理学报(A辑)》1997,17(4):473-478
将计算双曲型守恒律弱解的Lax-Wendroff型TVD格式推广到断面形状沿程任意变化的一般浅水方程组,构造了二阶精度的差分格式.新格式适用于模拟天然河道中溃坝洪水波的传播.提供了表明方法性能的算例,实际天然梯级水库溃坝问题的数值实验表明格式稳定,适应性强. 相似文献
243.
LI Yu-Lan CAO Liang-Jun QI Hui-Rong LI Jin KANG Ke-Jun LI Yuan-Jing LAI Yong-Fang GAO Yuan-Ning YANG Zhen-Wei 《中国物理C(英文版)》2008,32(1)
A time projection chamber (TPC) readout by gas electron multipliers (GEM) detector is a very promising candidate for the central tracking system of ILC (International Linear Collider). A prototype is designed and set up in our lab and introduced here. The tests during and after the assembly prove that the prototype TPC has been constructed successfully. It is ready for further study. 相似文献
244.
245.
T. Yoshioka 《Pramana》2007,69(6):1115-1118
Most of the important physics processes to be studied in the international linear collider (ILC) experiment have multi-jets
in the final state. In order to achieve better jet energy resolution, the so-called particle flow algorithm (PFA) will be
employed and there is a general consensus that PFA derives overall ILC detector design. Four detector concepts for the ILC
experiment have been proposed so far in the world; the GLD detector that has a large inner calorimeter radius, which is considered
to have an advantage for a PFA, is one of them. In this paper, general scheme and performance of the GLD-PFA will be presented.
相似文献
246.
John Hauptman 《Pramana》2007,69(6):1037-1046
The 4th concept detector consists of four detector subsystems, a small-pixel vertex detector, a high-resolution TPC, a new
multiple-readout fiber calorimeter and a new dual-solenoid iron-free muon system. We discuss the design of a comprehensive
facility that measures and identifies all partons of the standard model, including hadronic W → jj and Z → jj decays, with high precision and high efficiency. We emphasis here the calorimeter and muon systems.
相似文献
247.
Will McGuffey Ruby Quea Keith Weber Nick Wasserman Tim Fukawa-Connelly Juan Pablo Mejia Ramos 《International Journal of Mathematical Education in Science & Technology》2013,44(8):1166-1190
Prospective secondary mathematics teachers are usually required to complete several university advanced mathematics courses before being certified to teach secondary mathematics. However, teachers usually do not find these courses to be valuable for their teaching. We designed an experimental real analysis course with the goal of making real analysis content useful and relevant to teaching. Our approach was to ground the real analysis content in pedagogical situations that problematized a secondary mathematics topic, where the nuances of teaching secondary mathematics could be informed by the real analysis that was covered. The experimental course was implemented in a graduate teacher education programme with 32 pre- and in-service teachers (PISTs). After the course, we conducted focus group interviews with 20 of these PISTs to get feedback on how the course was valuable to their teaching practice. Many PISTs found the course to be valuable for teaching secondary mathematics, as well as for their understanding of secondary mathematics and real analysis. 相似文献
248.
"电路原理"、"信号与系统"和"自动控制原理"三门课程是光电信息科学与工程等专业的专业基础课。若分别采用各自独立的教学内容和方法,内容交叉、重复,浪费学时,没有从整个课程体系系统化的角度把握有关内容。因此,提出了适用于光电信息科学与工程等专业的以上三门课程的教学改革方案,从根本上系统地将这三门课程进行整合、优化为"电路、信号和控制系统"课程。在教学实践中,进行了有关内容的教学尝试,缩短了教学时间,提高了教学质量。 相似文献
249.
Regulations relating to mycotoxins in food 总被引:1,自引:0,他引:1
Regulations relating to mycotoxins have been established in many countries to protect the consumer from the harmful effects
of these compounds. Different factors play a role in the decision-making process of setting limits for mycotoxins. These include
scientific factors, for example the availability of toxicological data and occurrence data, detailed knowledge about possibilities
for sampling and analysis, and socio-economic issues. By the end of 2003, approximately 100 countries (covering approximately
85% of the world’s inhabitants) had specific regulations or detailed guidelines for mycotoxins in food. The regulations were
related to aflatoxins (B1, B2, G1 and G2), aflatoxin M1, trichothecenes (deoxynivalenol, diacetoxyscirpenol, T-2 toxin and HT-2 toxin), fumonisins (B1, B2, and B3), agaric acid, ergot alkaloids, ochratoxin A, patulin, phomopsins, sterigmatocystin, and zearalenone. In Europe, and in particular
in the EU, regulatory and scientific interest in mycotoxins has undergone a development in the last decade from autonomous
national activity towards more EU-driven activity with a structural and network character. Harmonized EU limits now exist
for 40 mycotoxin–food combinations. It is expected this number will grow in 2007 to approximately 50. The direct or indirect
influence of European organizations and programs on the EU mycotoxin regulatory developments is significant. They include
the European Food Safety Authority, the Scientific Cooperation on Questions relating to Food, the Rapid Alert System for Food
and Feed, the creation of an EU Community Reference Laboratory for Mycotoxins and a mandate of the EC to the European Standardization
Committee in methods for analysis for mycotoxins in food. Large pan-European research and networking projects as “BioCop”
and “MoniQA” are also important. 相似文献
250.
The entropy optimization approach has widely been applied in finance for a long time, notably in the areas of market simulation, risk measurement, and financial asset pricing. In this paper, we propose copula entropy models with two and three variables to measure dependence in stock markets, which extend the copula theory and are based on Jaynes’s information criterion. Both of them are usually applied under the non-Gaussian distribution assumption. Comparing with the linear correlation coefficient and the mutual information, the strengths and advantages of the copula entropy approach are revealed and confirmed. We also propose an algorithm for the copula entropy approach to obtain the numerical results. With the experimental data analysis at the country level and the economic circle theory in international economy, the validity of the proposed approach is approved; evidently, it captures the non-linear correlation, multi-dimensional correlation, and correlation comparisons without common variables. We would like to make it clear that correlation illustrates dependence, but dependence is not synonymous with correlation. Copulas can capture some special types of dependence, such as tail dependence and asymmetric dependence, which other conventional probability distributions, such as the normal p.d.f. and the Student’s t p.d.f., cannot. 相似文献