Acrobat的使用

随着A crobat广泛的使用,它日益成为办公软件中不可缺少的组成部分。该文简要介绍了A crobat5.0的一些使用方法。     

孕酮对正常生育和不明原因不育男性精子-仓鼠卵穿透试验的作用

目的　比较正常生育男性和不明原因男性不育症患者精子的受精能力及其对孕酮 (P)的反应性。方法　选择10例不明原因男性不育症患者和 10例正常生育男性 ,在上游后精子悬液中加入P 10 μmol·L -1,并体外获能 2h。采用超排卵法制备仓鼠卵细胞 ,将精子与卵子体外受精 3h后观察卵子受精率 (FR)与受精指数 (FI)。结果　上游后精子与P孵育能显著提高生育组的FR(P <0 .0 1) ,但不能增加不育组的FR ;生育组FR显著高于不育组FR(P <0 .0 0 1)。P能显著提高生育组的FI (P <0 .0 1) ,但不能增加不育组的FI;生育组FI显著高于不育组FI (P <0 .0 1)。结论　P能增强正常生育男性精子的受精能力 ;精子对孕酮的反应性降低可能是不明原因男性不育症的病因之一     

轿车车身公差分析优化系统研究

提出了一款车身公差分析优化系统。优化系统可以运用非合作博弈的纳什均衡效用矩阵进行公差分配优化,进行公差分析采用蒙特卡罗法验算所需测点间隙与高差,并预测超差率,针对分析结果的不同超差率,提供不同产品与工序更改方案,最后使用产生式规则和关系数据库扩充优化系统数据库。通过应用本款软件可以缩短设计周期,节约成本,提高公差水平。     

CLONING SEGMENT SPIKE PROTEIN GENE OF SARS-COV AND ITSEXPRESSION IN ESCHERICHIA COLI

Objective Expressing and purifying the seglnent of SARS-CoV spike protein in E. Coli Methods The target gene was obtained by RT-PCR. The PCR product was cloned into pEGM- T Easy Vector, sequencing and double restriction digestion (BamH Ⅰ , Pst Ⅰ) were performed. The target gene was subcloned into PQE30 expression vector. The gene was expressed in the E. coli strain M15 cells induced by IPTG. The protein was purified with a nickel HiTrap chelating metal affinity column. Results The recombinant expression plasmid was successfully constructed and the protein was well expressed in E. coli strain M15 cells. The ideal pure protein was obtained by purification. Western blotting analysis suggested the protein could act with the convalescent sera of lab confirmed SARS patients. Conclusion The segment of SARS-CoV spike protein was well expressed and purified, and can be applied in diagnosis and immunological research of SARS.     

Research on Improved Low-Energy Adaptive Clustering Hierarchy Protocol in Wireless Sensor Networks

In wireless sensor networks (WSNs), due to the limited battery power of the sensor nodes, the communication energy consumption is the main factor to affect the lifetime of the networks. A reasonable design of the communication protocol can effectively reduce the energy consumption of the network system. Based on low-energy adaptive clustering hierarchy (LEACH), an improved LEACH protocol in WSNs is proposed. In order to optimize the cluster head (CH) election in the cluster setup phase, the improved LEACH takes into account a number of factors, including energy consumption of communication between nodes, remaining energy of the nodes, and the distance between nodes and base station (BS). In the steady phase, one-hop routing and multiple-hop routing are combined to transmit data between CHs to improve energy efficiency. The forward CH is selected as relay node according to the values of path cost. The simulation results show that the proposed algorithm performs better in balancing network energy consumption, and it can effectively improve the data transmission efficiency and prolong the network lifetime, as compared with LEACH, LEACH-C (LEACH-centralized) and NDAPSO-C (an adaptive clustering protocol based on improved particle swarm optimization) algorithms.     

一种雷达辐射源信号分选新方法

提出一种基于小波与神经网络联合分析的雷达辐射源信号分选新方法.该方法首先对接收到的雷达信号进行小波去噪,达到提高信噪比的目的,然后利用小波脊线法准确提取其脉内特征参数,最后基于神经网络实现信号的分选.计算机仿真结果表明,较现有方法,该方法在较低的信噪比情况下,可以更准确地实现雷达辐射源信号的分选.     

An experimental study on flowrate and stability for 600MW supercritical steamturbine control valve

An experimental study on flowrate and stability of a type of control valve of 600MW supercritical steamturbine was presented by measuring instruments of static, dynamic pressure and vibration in self-designed test rig. The investigation shows that flow coefficient is 30% up more than that of the control valve of GX-1 type used widely in domestic power plants now, as small-medium lifts. If the relative lift （h/D） is less than 20%, the valve can always work steadily in all the pressure ratios. When the h/D is between 20% to 24%, big vibration of valve stem occurs if the pressure ratio is between 0.7 to 0.8. When h/D is more than 25%, relatively great vibration happens in a wide range of pressure ratios of 0.4 to 0.85.     

智慧物流驱动管理与决策智慧化

伴随大数据、云计算、人工智能等新一代信息技术的推动,以及智能制造、新零售等新需求的出现,迫切需要智慧物流驱动下的管理与决策促进物流的高质量发展.通过阐述智慧物流的发展背景和内涵特征,提出智慧物流的应用目标和路径——底层要素数字化、中间运营模型化、管理决策智能化.结合物流运力交易共享平台、第三方物流+互联网平台、快递智能...     

简支梁桥新型桥面连续构造设计与应用

针对目前简支梁桥桥面连续构造病害多发的现状, 综合分析了传统桥面连续构造的受力模式和破坏机理, 结果表明： 温度变化产生的主梁纵向伸缩、 活载产生的主梁绕支点的转动、 支座不均匀沉降以及车轮荷载的局部竖向压力等共同作用, 使得桥面连续构造受力复杂, 容易造成应力集中, 这是造成桥面连续构造病害的内在因素; 而设计的缺陷及计算分析的不全面, 使其构造及配筋随意性较大, 加上施工不精细, 这是造成桥面连续构造病害的外在因素。 为了解决以上问题, 文章提出了一种构造和受力均简单明确的桥面连续构造, 通过对桥面连续构造的设计创新, 使得新型桥面连续构造受力简单明确, 构造尺寸及配筋设计有的放矢, 克服了传统桥面连续结构受力复杂、 计算分析不清、 构造和配筋随意性大、 耐久性差、 病害多发的缺陷, 为简支梁的桥面连续结构的设计和应用提供了新的参考。     

基于加权灰关联模型的船舶性能综合评价

寻找一种科学实用的船舶性能综合评价方法一直是船舶研究者、设计者、制造者和使用者追求的目标之一，文中考虑到各因素重要性不同而采用加权的灰色关联模型，并将层次分析法和灰色关联分析法结合起来，对船舶性能进行综合评价，为船舶设计与制造提供了一种新的决策方法。