Evaluation method of cracking resistance of lightweight aggregate concrete

The cracking behavior of lightweight aggregate concrete（LWAC） was investigated by mechanical analysis, SEM and cracking-resistant test where a shrinkage-restrained ring with a clapboard was used. The relationship between the ceramsite type and the cracking resistance of LWAC was built up and compared with that of normal-weight coarse aggregate concrete（NWAC）. A new method was proposed to evaluate the cracking resistance of concrete, where the concepts of cracking coefficient ζt（t） and the evaluation index Acr（t） were proposed, and the development of micro-cracks and damage accumulation were recognized. For the concrete with an ascending cracking coefficient curve, the larger Acr（t） is, the lower cracking resistance of concrete is. For the concrete with a descending cracking coefficient curve, the larger Acr（t） is, the stronger the cracking resistance of concrete is. The evaluation results show that in the case of that all the three types of coarse aggregates in concrete are pre-soaked for 24 h, NWAC has the lowest cracking resistance, followed by the LWAC with lower water absorption capacity ceramsite and the LWAC with higher water absorption capacity ceramsite has the strongest cracking resistance. The proposed method has obvious advantages over the cracking age method, because it can evaluate the cracking behavior of concrete even if the concrete has not an observable crack.     

Freights loading optimization with balanced and unconcentrated loading constraints

The optimization of high density and concentrated-weight freights loading requires an even distribution of the freight＇s weight and unconcentrated loading on the floor of the car. Based on the characteristics of concentrated-weight category freights, an improvement method is put forward to build freight towers and a greedy-construction algorithm is utilized based on heuristic information for the initial layout. Then a feasibility analysis is performed to judge if the balanced and unconcentrated loading constrains are reached. Through introducing optimization or adjustment methods, an overall optimal solution can be obtained. Experiments are conducted using data generated from real cases showing the effectiveness of our approach： volume utility ratio of 90.4% and load capacity utility ratio of 86.7% which is comparably even to the packing of the general freights.     

Fabrication and thermal performance of grooved-sintered wick heat pipe简

Some novel grooved-sintered composite wick heat pipes（GSHP） were developed for the electronic device cooling.The grooved-sintered wicks of GSHP were fabricated by the processes of oil-filled high-speed spin forming and solid state sintering.The wick could be divided into two parts for liquid capillary pumping flow：groove sintered zone and uniform sintered zone.Both of the thermal resistance network model and the maximum heat transfer capability model of GSHP were built.Compared with the theoretical values,the heat transfer limit and thermal resistance of GSHP were measured from three aspects：copper powder size,wick thickness and number of micro grooves.The results show that the wick thickness has the greatest effect on the thermal resistance of GSHP while the copper powder size has the most important influence on the heat transfer limit.Given certain copper powder size and wick thickness,the thermal resistance of GSHP can be the lowest when micro-groove number is about 55.     

耐温耐盐乳状液驱替体系性能研究

对合适HLB值的乳化剂进行了筛选和评价,优选了具有较强稳定性能的乳状液。静态测试结果显示乳状液具有较好的耐温和耐盐性能,随着矿化度的提高,其稳定性能略有降低,但是幅度不大。该乳状液体系具有很高的黏度,渗流阻力能够提高140倍左右,说明乳状液体系能够在高温高盐条件下取得很好的驱替效果。驱替实验还表明乳状液滴与孔喉的匹配性决定了乳状液在多孔介质中的运移能力。     

大豆蛋白改性维纶纤维的电学性质研究

为了降低大豆蛋白改性维纶纤维在纺纱过程中的静电现象,通过测试不同温湿度状态下的大豆蛋白改性维纶纤维的比电阻,对大豆蛋白改性维纶纤维的质量比电阻与温湿度条件间的关系进行实验研究。实验结果表明,大豆蛋白改性维纶纤维和普通维纶纤维的质量比电阻随着相对湿度和温度的升高而降低;大豆蛋白改性维纶纤维和普通维纶纤维的质量比电阻对数,随着相对湿度和温度的升高而降低,而且相对湿度在60%以上及温度在30℃以内时,大豆蛋白改性维纶纤维的质量比电阻及质量比电阻对数低于普通维纶纤维,降低程度较明显。因此,适当提高温湿度条件,可以使纤维纺纱时的静电问题得到控制。该研究为大豆蛋白纤维纺织生产提供了理论依据。     

哈尔滨城市公交工况的构建

针对哈尔滨市开展新能源公交客车示范运行,客车动力系统的匹配及其优化问题,采用GPS设备对哈尔滨城市公交典型线路的运行工况进行了实测,将记录的车速曲线分割成运动片段,采用主成分分析法和聚类技术提炼了运动片段的特征,进而建立了哈尔滨城市公交工况,并分别与中国城市公交工况和曼哈顿城市公交工况的特征值进行对比分析.分析结果表明,哈尔滨城市公交工况的平均车速低于中国城市公交道路工况,平均加、减速等特征值则高于中国城市公交道路工况.怠速比例低于曼哈顿城市公交工况.建议公交车生产及研发部门采用哈尔滨市自身的公交行驶工况,匹配设计出更符合实际的新能源公交客车动力系统,并通过优化控制策略,进一步提高车辆行驶的经济性.     

全电子式有源程控电阻器的设计

提出了一种具有量程程控转换和阻值预置功能的电阻器设计方法,其实现电路由量程转换电路、增益设置电路和控制电路三部分组成,内部无继电器,具有多量程、阻值连续可调、分辨力高、准确度高等优点,针对提高电阻器分辨力和量程转换速度,以及消除导通电阻误差和引线误差,提出了具体的电路实现方法,对系统的分辨力和准确度进行测试验证,并通过分析实测数据可知,当阻值在0~1 kΩ范围时,分辨力可达到0.1Ω,阻值超过1 kΩ时,分辨力可达到1Ω.     

社会主义核心价值体系与高校校园文化建设

高校校园文化建设必须以社会主义核心价值体系来引领,它是社会主义核心价值体系的承担载体,也是学校精神文明建设的一部分。社会主义核心价值体系作为校园文化建设的核心,在引领校园文化建设方面,对青年大学生形成正确的价值观并且体现为他们的行动具有重大意义和深远影响。     

基于C8051F350三线制热电阻测温仪表的设计

详细阐述了基于C8051F350片上系统的热电阻测温仪表的工作原理与校准方案,并对测量误差进行了详细的分析,从整体上简化了传统测温仪表的电路结构,降低了仪表电路成本,同时也提高了的可靠性.     

以品牌专业建设为契机 抓住发展机遇 全面提高专业建设质量

专业建设是高等学校最重要的教学基本建设,是教育教学工作的基础和重要生命线,是高等学校人才培养的重要依托。加强本科品牌专业的建设可提升学校本科专业建设的整体水平,提高学校本科人才培养质量、效益和竞争力。文章围绕如何开展品牌专业建设,结合学校实际,着重从品牌专业内涵、建设原则、内容和评价办法等方面进行了阐述。