电表改装与校准

电表在测量中有广泛的应用,因此如何了解电表和使用电表就显得十分重要。电流计是用来测量微小电流的,允许通过的电流很小,本文用它来扩大量程。     

Simulation of top-down crack propagation in asphalt pavements

Top-down crack in asphalt pavements has been reported as a widespread mode of failure.A solid understanding of the mechanisms of crack growth is essential to predict pavement performance in the context of thickness design,as well as in the design and optimization of mixtures.Using the coupled element free Galerkin (EFG) and finite element (FE) method,top-down crack propagation in asphalt pavements is numerically simulated on the basis of fracture mechanics.A parametric study is conducted to isolate the effects of overlay thickness and stiffness,base thickness and stiffness on top-down crack propagation in asphalt pavements.The results show that longitudinal wheel loads are disadvantageous to top-down crack because it increases the compound stress intensity factor (SIF) at the tip of top-down crack and shortens the crack path,and thus the fatigue life descends.The SIF experiences a process "sharply ascending—slowly descending—slowly ascending—sharply ascending again" with the crack propagating.The thicker the overlay or the base,the lower the SIF; the greater the overlay stiffness,the higher the SIF.The crack path is hardly affected by stiffness of the overlay and base.     

以“唱红”和“打黑”为例试论“动词＋颜色形容词”结构

＂V＋颜色adj＂这种语言组合现象古已有之,近期活跃在各大媒体的＂唱红＂、＂打黑＂引起社会的广泛关注,本文作者拟从语言学的角度对＂唱红＂、＂打黑＂这种现象进行分析,并把它们与旧的＂V＋颜色ad j＂形式进行对此,试图发现此类词语出现的语言学理据。     

ZrV_2O_7/Al复合梯度材料制备及特性研究

采用湿化学/高温煅烧法制备ZrV2O7粉末,并以其和金属Al粉为原料,利用粉末冶金法的堆层技术制备ZrV2O7/Al复合梯度材料。通过XRD、SEM抗热震性实验分析,研究了材料的组织及强度。结果表明:湿化学/高温煅烧法制备的ZrV2O7粉末纯度高;在ZrV2O7/Al复合梯度材料中沿梯度材料纵截面方向的成分梯度过渡明显,各层之间结合紧密。热震性实验表明,ZrV2O7/Al梯度材料的耐高温强度高,各层之间粘结性好。     

断裂力学的工程应用

脆性破坏是零件失效的主要形式之一,传统的防脆断方法要么很保守要么照样产生脆性破坏.从断裂力学的角度讨论带裂纹体在实际工程中的应用.     

美国多元文化主义的缘起——以少数民族的遭遇和抗争为中心的考察

美国少数民族为美国政治、经济、社会与文化发展做出了巨大贡献,但长期以来他们在教育、就业和住房等方面仍遭受各种歧视。20世纪60年代美国少数民族强烈表达平等分享政治、经济和文化权利诉求,多元文化主义在美国逐渐兴起。     

Research on the protection effect of pioglitazone for non-alcoholic fatty liver disease （NAFLD） in rats

Objective： The prevalence of non-alcoholic fatty liver disease （NAFLD） has markedly increased. Insulin resistance has been implicated in the pathogenesis of NAFLD. This study was aimed at observing the relationship between insulin resistance and NAFLD, and evaluating the role of pioglitazone （PGZ） acting as insulin-sensitizing agents in the prevention and treatment of rat fatty liver induced by high fat feeding. Methods： The rats were separated randomly into 6 groups： model group Ⅰ were fed high fat diet for 8 weeks, PGZ prevention group were given PGZ 4 mg/（kg.d） simultaneously, while control group Ⅰ were fed normal food for 8 weeks; model group Ⅱ were fed high fat diet for 16 weeks, PGZ treatment group were given PGZ 4 mg/（kg.d） orally simultaneous with high fat diet for 8 weeks after high fat feeding for 8 weeks, control group Ⅱ were fed normal food for 16 weeks. The rats were sacrificed after 8 weeks and 16 weeks respectively. Liver weight, body weight, serum activities of alanine aminotransferase （ALT）, aspartate aminotransferase （AST）, alkaline phosphatase （ALP）, tumor necrosis factor alpha （TNF-α）, fasting blood glucose （FBG）, fasting plasma insulin （FINS）, HOMA （homeostasis model assessment） insulin resistance index （HOMA-IR）, and the liver histology of rats of all groups were assayed. Results： After 8 weeks, the liver in model group Ⅰ showed typical steatosis, accompanied with mild to moderate lobular inflammatory cell infiltration, liver indexes and serum levels of ALT, AST, ALP, TNF-α were significantly increased （P〈0.05） compared with control group Ⅰ. Whereas, the degree of hepatic injury was attenuated in PGZ prevention group, liver indexes and serum levels of ALT, ALP were significantly decreased （P〈0.05） compared with model group Ⅰ. After 16 weeks, notable steatosis, and lobular inflammation were observed in model group Ⅱ rat liver, while the degree of hepatic injury was attenuated in the PGZ treatment group. Liver index, serum levels ofALT, AST, ALP, FINS and HOMA-IR were significantly increased （P〈0.05） in model group Ⅱ compared with control group Ⅱ. Whereas, in PGZ treatment group, serum levels of AST and FINS showed decreasing tendency, liver indexes, serum levels of ALT, ALP, TNF-α and HOMA-IR were significantly decreased compared with model group Ⅱ. Conclusion： Insulin resistance plays a role in the pathogenesis of NAFLD in rats. Pioglitazone can attenuate insulin resistance and biochemical and histological injury in high fat-induced fatty liver in rats.     

从“西西弗”到“普罗米修斯”——个人反抗与群体反抗

作为“苦难与阳光之子”的加缪,在自身的创作中体现出独特的反抗精神,爱与信仰是其反抗精神的实质。在他的哲学随笔《西西带神话》和《反抗者》中,希腊神话人物“西西弗”与“普罗米修斯”是独具特色的反抗者形象,他们分剐为“个人反抗的代表”和“群体反抗的代表”,二者能够以独特的角度折射和再现出加缪的反抗精神。     

Resistance in action learning: struggling with self-efficacy and the social Self – and what about the set advisor?

This account of practice explores the concept of resistance in action learning. Resistance is conceptualized as an attempt of self-protection that is manifested in action learners' struggles with their sense of self-efficacy and their social Self. These struggles are an inherent part of the action learning process and may elicit defensive undercurrents that constrain learning. I contribute to debates on criticality in action learning by recognizing the centrality of resistance as a source of learning for participants and set advisors. The intended contribution of this paper is to illuminate the importance of engaging with these limiting processes which can spark a powerful learning experience that reverberates long after the action learning programme has finished. Furthermore, I reflect on the opportunities this alternative view on resistance may provide for us as action learning facilitators and discuss how we may incorporate these reflections in our practice.     

简易自动电阻测试仪的设计

文章介绍了一种简易自动电阻测试仪,可用于电子产品制作中电阻元件分类回收及筛选。本设计选用STC89C52型单片机作为主控芯片,介绍其硬件电路组成及软件系统的主程序流程,具有制作简单、性能可靠等优点。测试结果表明：该简易自动电阻测试仪测量结果符合设计要求,测量误差5％,为设计目标范围。