对照性实验的常见类型

高中生物各类考试中,经常出现对照性实验题,不同类型的实验应采用不同的方法.对照性实验有多种分类方法,常规方法分为探究性实验、验证性实验.下面依据实验需要设计的对照类型不同,分为以下几种类型,以便设计实验时提供思维方法上的参改.     

化学实验中创新教育的研究

对于化学实验,要更新实验思路,改变过去为做实验而做实验的意识,让实验能在学习中创新.实验中要引导学生观察,采用多种实验方法,激发学生学习兴趣.实验要重视方法总结,改变过去只以成绩来评价学生的观念.     

测定电池的电动势和内阻实验导学

一、明确学习目标 1.知道测量电源电动势和内阻的实验原理,掌握科学测量的步骤. 2.了解实验过程,掌握实验方法,学会根据图象合理进行数据处理的方法. 3.了解实验中误差的来源,了解测量中减小误差的方法. 4.培养仔细观察,真实记录数据等良好实验习惯和实事求是的品质.     

乙烯制备实验的再设计

目的 指出<关于乙烯制取实验的环保设计>一文中存在的不足之处;改进乙烯实验室制备方法.方法 文献资料与实验研究.结果 依据原实验原理,设计了新的实验方案,收到了良好的实验效果.结论 该方案乙醇转化率高,乙烯纯度高;且装置简单,操作方便,便于控制.便于连续作业,是一种较理想的实验演示方法.     

思想方法:物理实验教学的立足点

物理实验教学对物理学习的作用不言而喻.努力提取物理实验中蕴含的丰富实验思想方法,并深入解剖,培养学生的科学思想,应该是中学物理实验教学的立足点.在实践操作中,应明确安排物理实验的目的,注重经典实验方法的渗透,并通过多种途径促进实验方法的内化,从而拓展学生的实验视野,提高学生对实验思想方法的领悟,提高解决实际问题的能力,最大化地发挥实验教学的功效.     

光电效应演示实验的方法论分析

物理实验需要有一定的方法和实施方案.方法指为了解决某一具体问题从实践或理论上所采取的手段与方式的总和.进行物理实验方法和实验方案的研究,要善于了解实验的设计思想、实验手段、显示方法等,以便吸取实验设计中的精华,发现实验方法的关键所在.一个典型的物理实验,一般是由实验对象(实验中研究的客体)、实验源(实验的信号发生器)和实验效果显示器三部分组成.对于光电效应实验来说,实验对象是在光的照射下发出光电子的金属板,一般为锌板;实验源指用来照射金属板的光源,一般为弧光灯或紫外线灯;实验效果显示器指显示光电效应现象的装置,如静电计等.     

新型电力电子技术实验方法的研究

传统电力电子技术实验主要基于实验台操作方式,实验效果不是很好,比如:学生对实验台、实验操作不熟悉.误操作、实验装置损坏较多;分析和解决问题的能力较难建立.为此,提出了一种新型的实验方法:以计算机仿真为前导,以实验验证及设计为目标的双环节实验方法.基于专业的PSPICE仿真环境,开发了电力电子技术高仿真平台,与实验台高度一致.学生在仿真平台上可进行与实验台操作一样的连线,且可突破实验台的局限,可对模块内部操作,研究其对电路特性的影响.该方法对全方位训练学生实验技能、培养学生科学研究方法和创新思维、提高实验教学水平具有重要作用.     

伽利略的实验思想评述

伽利略善于运用理论思维指导实验选题,同时把实验和数学进行有机结合,依靠逻辑推理,并用实验来检验,构成一整套的实验科学方法.他设计的实验构思巧妙,蕴涵着丰富的实验思想,其卓越的实验思想及由此发展起来的物理学探索方法,为近代物理学奠定了基础.     

一种基于实物模型的频率特性实验的软件实现方法

介绍了用MATLAB软件进行频率特性实验的一种实现方法.将电阻、电容、电感等电子元器件模型与交流电源、电压表、示波器等模型按照与实物相同的连结方法进行实验,完全可以代替基于实物的实验,与传统的实物实验相比,本方法具有可重复性、读数精度高、灵活方便等特点,为实现虚拟实验或缺少实物实验条件的教学单位提供了解决方法.     

蛋白质免疫印记分析法实验条件的研究

蛋白质免疫印记分析(western blotting)是研究和分析蛋白质的重要手段.该文简述了western blotting的方法及实验过程,从实际操作的角度,着重探讨了实验条件的控制、影响因素和优化实验结果的方法.这些从实际工作和预实验中总结出来的优化方法,可以使实验结果更加明晰和易于进一步的分析研究.     

Experiments and sensitivity analyses for heat transfer in a meter-scale regularly fractured granite model with water flow

Experiments of saturated water flow and heat transfer were conducted for a meter-scale model of regularly fractured granite. The fractured rock model (height 1502.5 mm, width 904 mm, and thickness 300 mm), embedded with two vertical and two horizontal fractures of pre-set apertures, was constructed using 18 pieces of intact granite. The granite was taken from a site currently being investigated for a high-level nuclear waste repository in China. The experiments involved different heat source temperatures and vertical water fluxes in the embedded fractures either open or filled with sand. A finite difference scheme and computer code for calculation of water flow and heat transfer in regularly fractured rocks was developed, verified against both the experimental data and calculations from the TOUGH2 code, and employed for parametric sensitivity analyses. The experiments revealed that, among other things, the temperature distribution was influenced by water flow in the fractures, especially the water flow in the vertical fracture adjacent to the heat source, and that the heat conduction between the neighboring rock blocks in the model with sand-filled fractures was enhanced by the sand, with larger range of influence of the heat source and longer time for approaching asymptotic steady-state than those of the model with open fractures. The temperatures from the experiments were in general slightly smaller than those from the numerical calculations, probably due to the fact that a certain amount of outward heat transfer at the model perimeter was unavoidable in the experiments. The parametric sensitivity analyses indicated that the temperature distribution was highly sensitive to water flow in the fractures, and the water temperature in the vertical fracture adjacent to the heat source was rather insensitive to water flow in other fractures.     

肋片传热量计算的新讲解

提出了一种肋片传热量计算的新讲解方法,简化了肋片模型假设和传热量计算过程,方便老师讲解和学生掌握。     

拟南芥热激蛋白HSP70基因片段克隆实验体系的建立

以拟南芥为材料,对热激蛋白HSP70基因片段进行了克隆研究,获得了最佳的分子克隆实验体系．首先提取拟南芥总DNA,接着在热激蛋白HSP70编码区设计引物,扩增出HSP70编码区的片断,再将HSP70编码区的片断加上具有EcoRⅠ酶切位点双链的人工接头,通过EcoRⅠ对其进行酶切．再与经过EcoRⅠ酶切并已经去磷酸化的PUC19载体通过T4连接酶进行连接,然后将连接产物置人到感受态大肠杆菌细胞中（即转化）,并让这种细胞在含有Amp＋／IPTG／X—Gal的LB培养基上生长．挑取培养基上蓝白斑中的白斑,进行质粒DNA提取,通过酶切质粒DNA,从而初步判断目的片段已被克隆．     

甲醇燃烧温度的计算与热效率研究

探讨了计算理论燃烧温度的方法及推导过程．算出了甲醇的理论燃烧温度，以它为依据，计算出甲醇燃料的理论热效率，提出实测热效率向理论热效率靠拢的途径．     

混合法测量固体比热容实验的改进

混合法测量固体比热容实验一般采用蒸汽加热器对被测金属块进行加热,但用它测得的金属块的温度不准确,从而导致比热容不准确。采取水浴法来加热被测金属块,能够得到一个热平衡态的温度值,从而获得准确的比热容。     

New method of improving parts accuracy by adding heat balance support in selective laser sintering

In order to improve parts accuracy, a method of adding heat balance support （HBS） was proposed, and the detailed algorithm for generating HBS was developed. A number of experiments and a comparison between similar softwares, showed that the algorithm is efficient and feasible. Moreover, different features of riBS were studied for different kinds of materials, such as PS and nylon. The research findings indicate that automatically adding HBS can significantly improve the accuracy of the parts, and that the algorithm for generating HBS is efficient and precise.     

Study on performance of a packed bed latent heat thermal energy storage unit integrated with solar water heating system

INTRODUCTION Efforts of rational and effective energy man-agement, as well as environmental considerations, increase the interest in using renewable energy sources, especially solar energy. Because of discrep-ancy between the energy supply and demand in solar heating applications, a thermal energy storage (TES) device has to be used for the most effective utilization of the energy source. Energy storage combined with solar collectors and photovoltaic systems have been developed over the…     

采用热容计算热量方法的比较

本文讨论了常用的几种采用热容计算热量的方法的准确性及适用性,对我们充分了解和掌握化工过程中热量的正确计算方法具有一定的指导意义.     

低温热水地面辐射供暖应用探讨

低温热水地面辐射供暖系统由于其舒适、卫生、保健、不占面积、热稳定性好、高效节能等优点已越来越多地在建筑供暖中得到推广应用。该供暖系统的施工必须严格按照施工工艺操作进行。     

Influence of compression-expansion effect on oscillating-flow heat transfer in a finned heat exchanger

Compression and expansion of a working gas due to the pressure oscillation of an oscillating flow can lead to a temperature variation of the working gas, which will affect the heat transfer in the oscillating flow. This study focuses on the impact of the compression-expansion effect, indicated by the pressure ratio, on the heat transfer in a finned heat exchanger under practical operating conditions of the ambient-temperature heat exchangers in Stirling-type pulse tube refrigerators. The experimental results summarized as the Nusselt number are presented for analysis. An increase in the pressure ratio can result in a marked rise in the Nusselt number, which indicates that the compression-expansion effect should be considered in characterizing the heat transfer of the oscillating flow, especially in the cases with a higher Valensi number and a lower maximum Reynolds number.