饮水硼对固始鸡心肌组织结构发育的影响

硼及其化合物因可制成药品、防腐剂、化妆品、洗漱剂、化学肥料及消毒剂等而广泛用于工业、农业、畜牧业和医疗卫生部门[1,2].     

高校院系资料室特色数字资源建设新模式探讨

针对高校院系资料室特色数字资源建设中存在的问题和困难， 提出了以技术托管为手段，以主讲教师为主导，以学科带头人为主体建设特色数字资源的创 新模式，具有良好的可操作性和应用价值。

     

自然条件下滤减紫外辐射对烤烟生长及品质的影响

 为研究紫外辐射对丽江特色优质烟叶形成的影响,采用盆栽试验,用100%（对照）,7.6%,62.2%,51.4% 4种不同紫外辐射透过率的透明薄膜进行遮盖,研究其对烤烟生长及品质的影响。结果表明：（1）进行紫外辐射滤减后,烤烟农艺性状与对照差异不明显。（2）对照比各处理在烤烟生长的前期合成更多的光合色素,但从旺长后期开始其降解速度加快;随着紫外辐射增强,光合速率下降,各处理较对照分别下降2,2.4,4.1μmol/（m2·s）。（3）随着紫外辐射强度的降低,烟叶栅栏组织厚度和叶片厚度减小,各处理分别减少6.72,10.04,8.84μm和23.46,28.98,22.98μm。对照与处理之间差异极显著,但处理之间差异不明显。（4）一定范围内紫外辐射的增强能促进烟叶糖类化合物的合成,不利于含氮化合物的积累,对钾和氯含量无明显影响。随着紫外辐射的滤减,上部叶、中部叶、下部叶总糖分别减少2.75%-6.68%,3.37%-6.13%,0.98%-1.66%;上部叶、中部叶、下部叶还原糖分别减少0.42%-2.47%,0.63%-4.22%,3.40%-5.68%;上部叶、中部叶总氮分别增加0.21%-0.71%,0.05%-0.39%,下部叶减少0.07%-0.25%;上部叶、中部叶、下部叶烟碱分别增加0.14%-1.22%,0.05%-0.87%,0.34%-0.82%     

中国农村留守妇女研究述评

农村留守妇女是指丈夫外出打工而留守在农村家中的已婚妇女。以农村留守妇女心理—社会发展为主线,对以往研究的相关结果进行系统回顾,并指出已有研究的“弱势群体”假设和“男性主义”视角所带来的不足。未来研究,要在社会变迁的时代背景和“流动—留守”联结的框架下,考察既有家庭功能连续性暂时中断的条件下,不同类型留守妇女发展的历时轨迹,挖掘家庭生态系统的弹性机制,以期为留守妇女发展的家庭干预提供支持。     

国内冠词研究：回顾与前瞻

从上世纪80年代至今,国内冠词研究经历了从定性研究向定量研究的转变,从整体研究向局部研究的转变,研究更加全面和细化。主要研究成果显示研究者在研究初期主要是在理论层面概括地研究冠词的功能和用法;研究中期对冠词的研究更加细化,特别体现在对零冠词和冠词翻译的研究;研究后期运用了语料库方法研究学生如何习得冠词和冠词误用以及冠词在语篇中的运用。对国内冠词现状研究的回顾可以更好地为研究和教学提供方向。     

Integrated control technology for methane in mining faces

Methane drainage is an effective technological approach to manage methane in an integrated fashion. Based the actual conditions of the 11031 mining face of the Zhongling coal mine in P. R. China, we divided the origin of methane into three categories: methane of the coal mining layer, methane of the adjacent coal layer, and methane in the goaf. Combining current techniques for managing methane in the mining face, we analyzed the effects of seven methods for draining the methane: through the coal layer borehole, the sector borehole, the cross borehole, the high level borehole, the large diameter borehole, the pipe buried in the goaf, and a special return airway. We suggest improvements for implementing integrated control in the three dimensional space by the control principle of dividing the sources. We provide references for other projects.     

Non linear static analysis of thick reinforced concrete slabs with reinforcements under partitions

There are no clear design standards for the concealed beams or reinforcements under partitions in big and thick slabs which often appear in contemporary reinforced concrete residential buildings. Designers have to rely on engineering experiences to design such concealed beams or reinforcements. We built a local finite element method model of a real building in ANSYS. The model included shear walls, big slabs and partitions, and the underlying reinforcements. The element for reinforcement was Link8, and the others were solid elements. Specifically, the element for big slabs was solid65 which can asses the non linear behaviour of concretes. Based on analysis results, we discuss the internal forces of big slabs, partitions and reinforcements. We offer suggestions for the design of reinforcements and selection of partitions.     

Wind tunnel tests and numerical simulation on arches’static wind loads of half through arch bridge

Long span half through arch bridges have the flexible space structure. Wind loads on the arches are usually the key factor to the whole bridge. Taking an example of the Chongqing Caiyuanba Yangzi River Bridge in P. R. China, wind tunnel tests of single arch and double arches section models were conducted. The results of a single arch in the smooth flow show that arch drag variability is small, and the lift and moment variability are significantly large. The results of double arches testing show that the static forces of the windward arch are similar to the single arch. The three force coefficients of leeward arches vary with the space width ratio and the angle between the two arches. Static forces testing was simulated by the CFD software FLUENT. The static forces from the testing and the simulation were compared. The results show that the values match quite well with testing, and the drag forces mainly varied with the space width ratio.     

Frequency shift domain iterative analysis for frequency estimation of equilong signals

From the view of trick recognition, features of signal decomposition structure in existing frequency estimation methods were analyzed, based on which, a frequency shift domain decomposition structure was proposed. A compound signal was constructed by combining several simple signals corresponding to different times. The given information in the time domain can be adopted to form an information accumulation effect, such that the interference frequency and noise can be suppressed effectively by decreasing the calculation. To match the use of a frequency shift domain decomposition structure, a frequency shift equilong iterative algorithm suitable for equilong signals was proposed. Simulated experiments were carried out in numerous application environments. The results show better noise immunity and real time performance as well as higher frequency estimation precision.     

Engine crankshaft static strength analysis based on the finite element method

Focusing on the fracture issue of single cylinder engine crankshafts, a three dimensional solid model was built in CATIA. Pre treatments, such as plotting grids, were carried out through Hypermesh, and finite element analysis was done using MSC. Patran/Nastran. The results show that the fatigue safety coefficient cannot meet demand when nodular iron is the crankshaft material. This finding verifies the theoretical possibility of crankshaft fracture. A crankshaft using 40Cr theoretically would not fracture because the fatigue safety coefficient could meet the demand. Simulation correctness was verified by a 400 hour engine reliability test.