L-苯丙氨酸甲酯化反应(Ⅰ)——利用氨基酸分析仪分析L-苯丙氨酸及其甲酯

为研究Ｌ－苯丙氨酸的甲酯化反应，需要寻找一种能同时对反应物和产物进行准确测定的分析方法。利用氨基酸自动分析仪进行氨基酸及其酯化物的分析研究。结果表明该方法重现性、准确性均较好。     

Dynamic response of gravity dam model with crack and damage detection

Gravity dam is a typical structure that has been frequently used in the fields of water conservancy engineering, and the safety of the structure has received widespread attention recently. Due to earthquakes or other reasons, gravity dams normally have damage such as cracks in practical service. Damage in the structures can alter the structural dynamic behavior and seriously affect structural performance. Maintaining safety and integrity of the gravity dam structures requires a better understanding of dynam...     

Commentary of research situation and innovation frontier in hydro-structure engineering science

In order to utilize water and hydropower resources in China,multitudes of water projects are established or to be constructed as an integral part of the national economy's infrastructure.Under these circumstances,there are two outstanding problems:1) a mass of existing dams are in danger and 2) in the southwest water-conservancy construction plan,dozens of existing or planned dams are high dams or even super high dams with heights between 200 and 300 m.In accordance with demands of the National Program for ...     

Analysis of two models for metal hot-electron power generation

Hot electron emission means that electrons move over potential barriers to come out of the metal when the metal is being heated.Obviously,voltage will generate between electrons and the metal.Based on this,the model of metal hot-electron power generation is built.Free electron model of Sommerfeld is used to describe the movement of electrons in metal.According to the different width of potential barriers,two models are built.One assumes that electrons move from one metal to another mainly by moving over the...     

Field experiments on greenhouse gas emissions and nitrogen and phosphorus losses from rice paddy with efficient irrigation and drainage management

Greenhouse gas emissions,nitrogen and phosphorous losses through ammonia volatilization,leaching and surface drainage from rice paddy under efficient irrigation and drainage were analyzed based on field experimental data in order to reveal the eco-environmental impacts of efficient irrigation and drainage on rice paddy.The results showed that total methane emission from rice paddy under the controlled irrigation was reduced by more than 80% and total nitrous oxide emission increased by 15.9% compared with f...     

The numerical simulation of interface crack propagation without re-meshing

Based on the framework of the extended finite element method (XFEM), the enriched exponent discontinuous function is modified properly by introducing the rigidity ratio of two sides materials of interface crack, and the portion integral scheme is adopted for interface elements containing two materials. To embody the singularity of the crack tip, the triangle function is introduced directly. What’s more, the maximum loop stress fracture criterion is adopted to determine the extension direction in extended ma...     

Abnormality diagnosis of cracks in the concrete dam based on dynamical structure mutation

A method of the fuzzy cross-correlation factor exponent in dynamics is researched and proposed to diagnose abnormality of cracks in the concrete dam. Moreover, the Logistic time series changing from period-doubling bifurcation to chaos is tested first using this method. Results indicate that it can distinguish inherent dynamics of time series and can detect mutations. Considering that cracks in the concrete dam constitute an open, dissipative and complex nonlinear dynamical system, a typical crack on the do...     

长春市南湖中街公租房项目探析

近年来,长春市积极响应国家保障性住房政策,推出万套公共租赁房政策,为“夹心层”这部分社会群体提供了新的住房契机与住房选择,也很大程度上完善了保障性住房体系的建设。本文选取南湖中街公租房项目,对其规划设计、建筑立面、建筑户型、节能取暖设施设计、小区配套及商业服务、环境、景观绿化、交通方面等内容的阐述。试图探索出一条更适应我国国情发展方向的公共租赁房之路。以推动我国保障性住房体系高效合理的发展。     

提高近红外视象管制靶工艺稳定性研究

根据近红外视象管特点,设计了专用的靶面蒸涂设备,改进了靶面加热方法、蒸发舟的形状以及工作气流的控制方法,确定了一种稳定性较好的工艺,使制靶成品率大大提高,整管成品率因此从过去的5%提高到30%。     

超细粒子催化剂的研究进展及其应用

介绍了超细粒子催化剂的性质及现有的一些制备方法，并对制备方法的优缺点进行了评价。着重探讨了溶胶-凝胶技术所具备的特点及一些内在缺点，并展望了超细粒子催化剂的应用前景。