A genetic variation map for chicken with 2.8 million single-nucleotide polymorphisms

We describe a genetic variation map for the chicken genome containing 2.8 million single-nucleotide polymorphisms (SNPs). This map is based on a comparison of the sequences of three domestic chicken breeds (a broiler, a layer and a Chinese silkie) with that of their wild ancestor, red jungle fowl. Subsequent experiments indicate that at least 90% of the variant sites are true SNPs, and at least 70% are common SNPs that segregate in many domestic breeds. Mean nucleotide diversity is about five SNPs per kilobase for almost every possible comparison between red jungle fowl and domestic lines, between two different domestic lines, and within domestic lines--in contrast to the notion that domestic animals are highly inbred relative to their wild ancestors. In fact, most of the SNPs originated before domestication, and there is little evidence of selective sweeps for adaptive alleles on length scales greater than 100 kilobases.     

Direct observation of the clockwise light-driven rotation of F<Subscript>0</Subscript>F<Subscript>1</Subscript>-ATP synthase complex

The purified thermophilic bacterium PS3 F₁ β _10×His-tag is inserted into the F_oF₁-ATP synthases of chro-matophores isolated from photosynthetic bacteria Rhodo-spirillum rubrum. The studies of biochemical properties of the hybrid chromatophores show that they have both protons-driving capability and photophosphorylation. The fluorescent actin filaments, as a marker of its orientation by video-microscopic experiment, are connected via Maleimido-C₃-NTA to the reconstituted β_10×His-tag of F_oF₁-ATP synthases. The clockwise rotation of F_oF₁-ATP synthases driven by light is observed directly when viewed from the F_o side to F₁. This system should be valuable for further studying the coupling property of F_oF₁-ATP synthase.     

多牵引床网络化控制系统设计

医疗保健牵引床的应用非常广泛，但是目前市场上的牵引床多为机械式手工操作，医护人员的工作量较大．文章提出了一种基于网络的智能型微电脑控制牵引床设计方案，牵引床控制系统采用89C52为核心，上位机基于WINDOWS操作系统结合数据库技术控制多台牵引床，可方便地构建医疗网络，也可单台使用．     

热油管道非稳态工况传热与流动的耦合计算模型

在进行热油管道工艺计算和运行工况分析时,通常将热力非稳态工况近似按稳态处理,这使得计算结果与实际情况偏差很大,不能客观地反映实际工况。在充分考虑管内油流热力、水力耦合以及管内油流与管外介质耦合的基础上,提出了一个比较完整的非稳态工况传热与流动双层耦合模型。采用双特征线法求解管内油流参数,用有限单元法求解管外土壤温度场,并编制了相应的计算程序。利用该模型和英国ESI公司的管道模拟软件TLNET分别对所建立的几种热油管道非稳态工况进行了模拟计算。结果表明,该模型比较合理,可用于热油管道非稳态工况的计算。     

高硼钢的组织与性能

用真空感应炉制备硼分布均匀的高硼钢,分析了其铸态和热轧态的显微组织.钛的加入减少了在晶界处析出的铁硼相Fe2B,FeB的数量,改善了其在GB的分布状态.钛硼相TiB2弥散地分布在铁素体基体上.确定了高硼钢热轧成形的合理工艺参数为加热温度1080～1120℃,初轧温度1070～1110℃,终轧温度810～850℃,道次压下量约10%～20%.采用多道次循环轧制,随后的冷却方式为空冷.热轧后高硼钢的力学性能得到明显提高.     

史学的功用

笔者在对史学作了简单的地位定位的基础上,从史学与个人、史学与社会两个角度,谈了自己对史学的功用的认识。     

广义LV系统的运动不变量和哈密顿函数

给出了可作为具有相应Poissn结构的GLV系统的哈密顿函数和运动不变量的一类函数及代数条件.并且定理的代数条件是独立的.利用主要定理2很容易证明一个系统是否具有文中所给哈密顿函数的哈密顿系统.     

纳米MnO2超级电容器的研究综述

介绍了纳米MnO2用作超级电容器电极材料的优势,从MnO2的制备、导电剂、电解质溶液和向MnO2晶格中掺入其他元素四个方面综述了目前纳米MnO2超级电容器的研究现状,并对未来的研究进行了展望。纳米MnO2电容器兼具双电层电容和氧化还原电容两种电荷储存机制,是一种很有前途的超级电容器电极替代材料。     

Reliability analysis of DOOF for Weibull distribution

Hierarchical Bayesian method for estimating the failure probability Pi under DOOF by taking the quasi-Beta distribution B(pi-1 , 1,1, b ) as the prior distribution is proposed in this paper. The weighted Least Squares Estimate method was used to obtain the formula for computing reliability distribution parameters and estimating the reliability characteristic values under DOOF. Taking one type of aerospace electrical connectoras an example, the correctness of the above method through statistical analysis of electrical connector acceler-ated life test data was verified.     

弹丸失效规律及有效贮存期预测研究

目的提出一种根据库存弹药性能变化的有限检测数据预测弹药产品有效贮存期的方法。方法随机抽取不同贮存年限的少量库存弹药,进行其炸药装药检测分析,获得贮存安全性和使用可靠性失效规律特征。应用灰色系统理论建立相应的功能失效模型,根据弹药产品管理规定和要求,获得其有效贮存期,结果对某弹丸有效贮存期进行预测,所得结果与试验结果一致。结论该方法可用于对现有库存弹药的有效贮存期进行预测。