嵌入式实时操作系统μC\OS-Ⅱ基于ARM9移植

文章就嵌入式操作系统μC\OS-Ⅱ的特点以及移植的要点作了介绍,并阐述μC\OS-Ⅱ中OS-CPU.H,OS-CPU-A.ASM和OS-CPU-C.C,将μC/OS-II操作系统移植到ARM9处理器S3C2410上并进行测试,测试后移植成功.     

NaCl溶液中20Cr9Ni5Co14不锈钢电化学腐蚀行为

采用电化学极化技术(动电位极化技术、线性极化技术和循环极化技术)和交流阻抗技术研究了不同条件下20Cr9Ni5Co14超高强度不锈钢的电化学腐蚀行为,并采用扫描电镜对极化后腐蚀形貌进行了表征.结果表明,20Cr9Ni5Co14钢在3.5%(质量分数)Na Cl溶液中出现钝化.随着Na Cl浓度的升高,钝化现象消失,而自腐蚀电流密度从8.223×10-7A/cm2减小至1.129×10-7A/cm2;随着p H值的降低,20Cr9Ni5Co14钢的致钝电位和过钝化电位增加.在p H值高于3时,腐蚀产物膜具有良好的耐腐蚀性能而导致反应步骤成为控制步骤.而当p H值降低到2时,腐蚀产物溶解速度很快,金属界面发生腐蚀速率很大,浓差极化成为了控制步骤.对腐蚀形貌研究表明,20Cr9Ni5Co14钢在极化过程中出现点腐蚀,导致了材料的耐腐蚀性能下降.     

猪Smad7和Smad9基因克隆、序列分析与组织表达图谱探究

本研究采用RT-PCR方法,从长白猪脑中克隆了 Smad7和 Smad9的基因 cDNA 全长。序列比对发现 Smad7和 Smad9在不同物种中保守性很高。同时,RT-PCR 检测发现：Smad7和Smad9在家猪各组织中广泛表达。这些结果提示：Smad7和 Smad9可参与家猪众多生理过程的调节。     

Stat3调控MMP9和TIMP1的转录与表达

通过脂质体瞬时转染Stat3重组质粒的方法在NIH3T3细胞中过表达Stat3;采用RT-PCR,Western blot以及荧光素酶活性分析的方法评估Stat3对MMP9及对其内源性抑制因子TIMP1的影响.结果表明:Stat3可增强MMP9及TIMP1基因启动子的活性,促进两者的转录与表达;并且Stat3对TIMP1的促进作用明显强于对MMP9的促进作用,从而使ECM的降解能力减弱,细胞外基质成分积累,导致纤维化的发生.     

CRISPR/Cas9基因转录激活技术的建立及其应用

建立基于CRISPR/Cas9的基因转录激活技术,实现在HEK293细胞中激活cGAS基因的转录。首先利用慢病毒载体构建稳定表达Cas9的HEK293细胞;并采用Real-time PCR和western blot方法鉴定Cas9蛋白质表达效果。再选取不同靶序列,分别构建用于激活cGAS基因转录的sgRNA载体,将构建好的序列载体与CRISPR体系工具质粒共转染至稳定表达Cas9的HEK293细胞中。采用Real-time PCR方法检测细胞中内源cGAS的转录激活效果。成功建立了基于CRISPR/Cas9的基因转录激活技术,并在c GAS基因阴性表达的细胞中激活基因的转录。     

Genome editing and animal models

Transgenic technology allows a gene of interest to be introduced into the genome of a laboratory animal, and provides an extremely powerful tool to dissect the molecular mechanisms of disease. Transgenic mouse models made by microinjection of DNA into zygotic pro- nuclei in particular have been widely used by the genetics community for 30 years. However, it remains a rather crude approach： injected sequences randomly insert in multiple copies as concatamers, they can be mutagenic, and they have variable or silenced expression depending on the site of integration, a phenomenon called position effects. As a result, multiple lines are required in order to confirm appropriate transgene expression. This can be partially overcome by flanking transgenes with insulator sequences to protect the transgene from the influence of the sur- rounding regulatory elements. Large （〈300 kb） BAC- based transgenic vectors have also been shown to be more resistant to position effects. However, animals carrying extra copies of fairly large regions of the genome could have unpredictable phenotypes. The most effective method used to control for position effects is to target transgene insertion to specific genomic loci, the so-called targeted transgenesis; for instance, the fast, site-specific transgenic technology TargattTM. The purpose of this review is to provide an overview on the current existing methods for making targeted transgenic mouse models.     

虚拟项目教学法在模拟电子技术教学中的应用

虚拟项目教学法是基于计算机模拟仿真技术的一种教学活动。将虚拟项目教学法应用到模拟电子技术的教学中,通过项目任务的设计、项目准备、仿真实施及总体评价展开教学。该方法不仅可以达到传统项目教学法的教学目标,而且可以扩大学生的参与面,降低教学成本。实践表明,该方法适合于应用型人才培养目标下的模拟电子技术教学。     

Multisim 9在电子线路课程设计的应用

结合电子线路课程教学、电子线路课程设计实践,通过二级放大电路实例介绍Multisim 9软件在电子线路课程设计中的应用,该软件能优化电路设计,实现电路功能仿真及提高电路设计开发水平与分析电路的能力。     

Hélène Metzger: the history of science between the study of mentalities and total history

In this article, I examine the historiographical ideas of the historian of chemistry Hélène Metzger (1886–1944) against the background of the ideas of the members of the groups and institutions in which she worked, including Alexandre Koyré, Gaston Bachelard, Abel Rey, Henri Berr and Lucien Febrve. This article is on two interdependent levels: that of particular institutions and groups in which she worked (the Centre de Synthèse, the International Committee for History of Science, the Institut d'Histoire des Sciences et Techniques (Sorbonne) and the École Pratique des Hautes Études) and that of historiographical ideas. I individuate two particular theoretical aspirations pursued by the historians in Metzger's milieu: the ideal of total history and the study of the human mind. These two objectives were seen by Metzger and many others as implicating each other. Moreover, Metzger and other historians wanted to integrate the practice of commentary of texts in the realisations of those ideals. I argue, however, that these objectives proved very difficult to realise at the same time. One tradition which stemmed out of these discussions, exemplified by Bachelard, Canguilhem and Foucault, focused on the mind and knowledge, and renounced commentary of texts and total history as it was understood by the historians of the Centre de Synthèse. The latter, however, did not really pursue the study of the mind. Moreover, historians like Metzger and Koyré who practised an attentive analysis of texts could not realise total history.     

智能小车辅助平台的设计与实现

讨论了一种以教学为目的的智能小车开发平台的设计思想,描述了智能小车的机械平台结构,给出了以FreescaleMC9S08GB60为主控芯片的、开放的硬件平台设计,提供了可供用户自行“定制开发设计”的、简单易学的PC方软件平台设计。该辅助开发平台主要针对中小学课外科技活动开发,也可供高校学生进行智能小车设计、参加智能小车设计竞赛之用。