基因工程实验创新性教学实践与探索

基因工程实验是一门理论与技术并进的新兴学科,传统的实验教学不能使学生很好的对这门课程进行系统的理解。创新性实验教学的开设有利于提高学生的综合能力。该文对基因工程创新性实验教学进行了初步的实践与探索,介绍了一些经验与体会。     

门控伺服式交流稳压器的设计

分析了目前市场上常见的各类稳压器的工作原理及存在的缺陷,并对已获得国家实用新型专利的门控伺服式交流稳压器的设计过程及工作原理和特点进行了技术、经济分析.     

儿科门诊不合理抗菌药物处方分析

<正>为了预防医源性疾病的发生,协助医生正确选择和应用药物治疗,确保病人用药安全和合理,作者对我院儿科门诊抗菌药物应用情况进行了调查,现报道如下。 1 一般资料 本次调查抽查了我院儿科从1998年1月1日至6月31日共6个月的门诊处方4960张,采取随机抽取法共取1000张,其中含有抗菌药物处方的958张,发现其中不合理用抗菌素处方63张,占抗菌用药处方的6.58％。 2 结果     

油毡防水平屋面施工方法

随着住房制度改革的深化,人们对房屋质量更为关注,尤其是对屋面渗漏最为关心。而屋面渗漏常常与设计、材料、施工、维修等多种因素有关。诚然,随着建筑业的发展,新型的防水材料日益增多,但目前传统的油毡防水屋面仍在我国广泛使     

月季快速繁殖应用的研究

本试验采用全光雾扦插育苗技术，使用萘乙酸和吲噌丁酸两种生长激素块速繁殖月季，与传统繁殖方法相比较，具有生根迅速，成活率高，生长周期短，植株生长健壮，提前花期的特点。     

Structure and magnetic properties of Ni50Mn35In15 thin film

Thin film of Ni50Mn35In15 Heusler alloy was prepared on Mg O(001) substrate by epitaxial growth in an ultra-high vacuum(UHV) chamber by a Pulsed Laser Deposition(PLD) method. The epitaxial growth process was monitored by in situ reflection high energy electron diffraction(RHEED) and the structure of the film was checked by ex situ X-ray diffraction(XRD), which indicates that high quality Ni50Mn35In15 single crystal film with a face-centered-cubic(fcc) structure could be stabilized on Mg O(001). Magnetic property measurement was also conducted at various temperatures by using physical property measurement system(PPMS). A significant exchange bias was observed for Ni50Mn35In15 film,and the strength of the exchange bias field(HEB) increases with the decrease of temperature. Such a behavior can be ascribed to the fact that the interfacial spin interaction between ferromagnetic(FM) and antiferromagnetic(AFM) cluster is enhanced with the decrease of temperature.     

基于ISM与FMECA的加工中心故障分析

故障分析是实现加工中心可靠性水平增长的重要环节,因此提高故障分析的准确性至关重要.鉴于此,本文首先充分考虑加工中心故障子系统间影响关系,基于ISM法构建递阶结构模型,使得关联故障子系统间复杂影响关系层次化,以求得深层故障子系统,确定可靠性改进薄弱环节.其次对所得薄弱环节进行FMECA分析,进而确定关键故障模式,为提高加工中心可靠性奠定基础.最后以某系列加工中心现场故障数据为研究对象进行实例研究,证明了ISM和FMECA法在加工中心故障分析中的准确有效性.     

浅谈水电站综合布线系统

改革开放以来,我国科学技术水平不断发展,信息化水平不断提高,电力系统也面临着很好的发展机遇,为了满足水电系统对技术的需要,综合布线系统应运而生。本文简要介绍了综合布线系统的现状,以及综合布线系统的特点,希望对相关方面工作人员有所帮助。     

基于Monte Carlo仿真的随机S曲线研究

PB-S曲线是随项目进展变化的累计预算成本曲线和累计工期曲线,它综合考察了成本、工期和项目进展百分比三个变量之间的关系.SS曲线提供了与各个项目进展百分比对应的累计预算成本和累计工期的概率分布.采用Monte Carlo仿真和统计分析方法,结合一个费用和时间随机分布的网络计划,详细研究了PB-S曲线和SS曲线的仿真建模和统计分析过程.进一步,基于SS曲线,考察了费用偏差和进度偏差的统计特征,为项目绩效的预测和监测提供更详细的偏差信息.同时针对均值曲线作为基准计划曲线的局限性,提出了两种新方法用于选择一定置信度要求的PB-S曲线作为项目的基准计划曲线.     

Inhibition of DNA restrictive endonucleases and Taq DNA polymerase by trimalonic acid C60

Activities of trimalonic acid fullerene (TMA C_60) on DNA restrictive enzymatic reaction were investigated by using two restrictive endonucleases Hind III and EcoR I and plasmid pEGFP-N1 with single restric-tive site for both enzymes. Meanwhile, TMA C60 was also tested to clarify its effects on polymerase chain reaction (PCR) with the catalyst of Taq DNA polymerase and the template of plasmid pEGFP-N1. The products from restrictive reactions or PCR were detected by agarose gel electrophoresis. It was found that the product amounts from restrictive reactions or PCR decreased significantly with addition of TMA C60. The inhibition by TMA C60 was dose-dependent and IC50 values for reactions of Hind III, EcoR I and PCR were 16.3, 6.0 and 6.0 μmol/L, respectively. Addition of two scavengers of reactive oxygen species (ROS), L-ascorbic acid-2-phosphate ester magnesium and sodium azide at the con-centrations of 2―10 mmol/L did not antagonize the activities of TMA C60 against PCR and two restrictive reactions. However, increase of Taq DNA polymerase amounts in PCR system antagonized the activities of TMA C60. These data implied that TMA C60 was able to inhibit the activities of the three above-mentioned enzymes involved in DNA metabolism, and that this inhibition probably did not correlate to ROS.