关键词： 蒸汽流量   工程公司   英国女王   国家级荣誉   Queen   医疗机构   数学算法   温度传感器   蒸汽系统   重复测量  

摘要： 2015年4月21日,斯派莎克工程公司因其创新性的产品荣获英国国家级荣誉的女王大奖（The Queen’s Awards）,以表彰一款独特流量计产品的设计与制造在商业领域的成功。相对于传统的蒸汽流量测量产品,斯派莎克TVA流量计是革命性的创新产品。它能提供可靠、精确和高性价比的蒸汽流量测量,易于快速安装在多种环境和行业中,包括食品饮料制造、医疗机构、大学校园、石化工厂等。

关键词： ALGEBRAIC fields   CATEGORIES (Mathematics)   ALGORITHMS   SPLITTING extrapolation method   MATHEMATICAL proofs   POLYNOMIALS  

摘要： A computably presented algebraic field F has a splitting algorithm if it is decidable which polynomials in F[X] are irreducible there. We prove that such a field is computably categorical iff it is decidable which pairs of elements of F belong to the same orbit under automorphisms. We also show that this criterion is equivalent to the relative computable categoricity of F.

关键词： Algorithmic differentiation   Differential algebraic equations   Sensitivity analysis   Tree algorithms   Equation-based languages   Modelica  

摘要： This work presents a novel Algorithmic Differentiation (AD) approach for sensitivity analysis of Differential Algebraic Equation systems (DAEs). For the first time, the algorithmic specification of a computationally memory-efficient equation-based AD technique is presented. This approach is mainly targeting equation-based modeling and simulation tools capable of constructing high-level models using state of the art object-oriented modeling principles. The approach is based on fundamental tree algorithms that are (even manually) applicable on implicit equation systems of long formulas, the main building blocks of model components. By applying the presented forward differentiation scheme on a given DAE, efficient representation of Sensitivity Equation Systems (SESs) is computed. Parameter sensitivities are evaluated by direct integration of the derived SESs. To overcome the runtime performance drawback of direct numerical integration, a system decomposition approach is recommended. It is shown that the runtime performance using modern variable-step integration methods tends to achieve the expected theoretical complexity of the forward differentiation scheme under few realistic assumptions. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Multiple representations   Algorithms   Rational numbers   Middle school  

摘要： This study examined the impact of the order of two teaching approaches on students' abilities and on-task behaviors while learning how to solve percentage problems. Two treatment groups were compared. MR first received multiple representation instruction followed by traditional algorithmic instruction and TA first received these teaching approaches in reverse order. Participants included 43 seventh grade students from an urban middle school in Midwestern USA. Results indicated gains in knowledge from both treatment groups;however, the differences between groups were nonsignificant. Comparisons of effect size however, indicated larger growths in abilities to solve among students who received multiple representation instruction first. In addition, statistical differences between on-task behaviors were found in favor of the traditional algorithmic approach.

关键词： TRICHODERMA viride   CADMIUM   BIOMASS   METAL biodegradation   GENETIC algorithms   MATHEMATICAL analysis   SUPPORT vector machines  

摘要： We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R-2 > 0.99. The value of the mean free energy of adsorption, E, is less than 16 kJ/mol at 25 degrees C, suggesting that, at low temperature, the dominant process involved in Cd(II) biosorption by dead T. viride is the chemical ion-exchange. With the temperature increasing to 40-50 degrees C, E values are above 16 kJ/mol, showing that the particle diffusion mechanism could play an important role in Cd(II) biosorption. The studies on T. viride growth in Cd(II) solutions and its bioaccumulation performance showed that the living biomass was able to bioaccumulate 100% Cd(II) from a 50 mg/L solution at pH 6.0. The influence of pH, biomass dosage, metal concentration, contact time and temperature on the bioremoval efficiency was evaluated to further assess the biosorption capability of the dead biosorbent. These complex influences were correlated by means of a modeling procedure consisting in data driven approach in which the principles of artificial intelligence were applied with the help of support vector machines (SVM), combined with genetic algorithms (GA). According to our data, the optimal working conditions for the removal of 98.91% Cd(II) by T. viride were found for an aqueous solution containing 26.11 mg/L Cd(II) as follows: pH 6.0, contact time of 3833 min, 8 g/L biosorbent, temperature 46.5 degrees C. The complete characterization of bioremoval parameters indicates that T. viride is an excellent material to treat wastewater containing low concentrations of metal.

关键词： Ion Selective Electrode array   Prussian Blue modified Carbon Paste Electrode   ISE array re-calibration   Genetic Algorithm  

摘要： With proper training procedures, including the use of a sufficiently large training sample set, ISE array with Back-Propagation Neural Networks (BPNNs) can be used to simultaneously determine the concentrations for multiple ions in environmental water. However, it is not practical for end-users to re-measure the whole training sample set - dozens of samples - to re-build the BPNN model every time after a long storage or measurement period, since both the sensitivity and selectivity of ISEs would be gradually degraded over time. In this study, instead of using BPNNs, we developed and patented some mathematical models to describe the based characteristics of the ISE array's response, including the sensitivity and selectivity. The developed mathematical equations can be used to simulate the response values of ISE array, and to determine the analytes' concentrations from unknown samples. By measuring only a couple of standard solutions, which are practical to the end users, the ISE array can be automatically recalibrated using genetic algorithm (GA). This research is based on an array of Prussian blue modified Carbon Paste Electrodes (PB-CPEs), and the interferences between nitrate (NO3) and chloride (Cl) was used as a case study. (C) 2015 Elsevier B.V. All rights reserved.

关键词： 古代文明   数学史   天文学史   科学史研究   自然科学史   古都西安   算法程序   周髀   陈起   mathematics  

摘要： 2015年8月24日-27日,西北大学数学与科学史研究中心在古都西安举办了“International Conference on theHistory of Ancient Mathematics and Astronomy”（古代数学史与天文学史国际会议）。该中心是国内一个重的科学技术史研究基地,她的前身是李继闵（1938-1993）教授于1985年创建的自然科学史（数学史）研究室。

关键词： 算法多样化   价值取向   问题   策略  

摘要： 算法多样化是《数学课程标准》中一种全新的教学理念，是问题解决策略多样化的一种重要体现。提倡算法多样化就是让学生进行自主探索，有效发展学生的独立思考和创造性思考的能力。算法多样化的实施不但有利于教学面向全体学生，而且有利于因材施教，促进学生个性发展，更有利于培养学生的创新思维。本文从算法多样化的概述、教学价值取向、教师在算法多样化教学主要存在的问题以及运用算法多样化的有效策略几方面进行了分析，希望能对小学数学教学提供帮助。

ISBN: (纸本)9787118100372

关键词： 数学算法   编程   效率   数学模型  

摘要： 现如今,我国的科技水平不断提高,计算机已经普遍用于人们的生活及工作中,并产生了重要的影响。现在的计算机软件,大多都是依靠编程来运行工作的,其编程好坏会直接对软件运行的效率高低造成很大的影响。所以,在进行软件研发的过程中,必须优化其程序,使软件运行工作的效率更高,进而为人们带来更多的便捷,促进人们的生产及工作。在我国古代数学中存在一种数学算法,而在计算机信息网络盛行的今天,计算机数学其实就是数学算法,充分的利用了数学的算法以及数学的原理,适当的建立数学模型,从而使之转化成为了计算机的编程,提高了计算机软件的工作效率。