A study on piezoelectric energy harvester using kinetic energy of ocean

Electricity generation through fossil fuels has caused environmental pollution. Accordingly, research on new renewable energy (solar, wind, geothermal heat, etc.) to replace fossil fuels and solve this problem is in progress. These devices can consistently generate power. However, they have several drawbacks, such as high installation costs and limitations in possible set-up environments. Therefore, the piezoelectric harvesting technology, which is able to overcome the limitations of existing energy technologies, is actively being studied. The piezoelectric harvesting technology uses the piezoelectric effect, which occurs in crystals that generate voltage when stress is applied. Its advantages include a wider installation base and a lower technological cost. This study investigated a piezoelectric energy-harvesting device based on constant wave motion. This device can harvest power in a constant turbulent flow in the middle of the sea. The components of the device are circuitry, percussion bar, triple layer piezoelectric bender, bearing and rudder. A multiphysical analysis coupled with the structure and piezoelectric elements was also conducted to estimate the device performance. The analysis accuracy was improved by applying the impact energy to the bender calculated based on the shape of the wave in the East Sea. The proposed device’s performance was finally confirmed by experiments.     

多功能结构在固体火箭上的应用分析

为实现固体火箭轻质化设计,采用传统机械结构优化的方法能力十分有限。多功能结构优化设计方法,由于采用机、电、热一体化的系统工程级设计思路,为提升火箭整体性能开辟了一个全新的方向。介绍多功能结构设计方法及思路,结合一种新型箭载记录设备原型样机的研制,对多功能结构在固体火箭领域应用的前景进行深入探讨。     

实验药包爆炸应力波测试技术探讨

用压电晶体压力传感器测定实验药包在介质中产生的爆炸应力波,没有反映冲击能（E_）和膨胀能（E_b）对介质进行加载的实际情况。本文指出电阻应变传感器具备记录压缩相和拉伸相的能力,认为超动态应变测试系统适宜于测定爆炸应力波,并给出了用该系统对爆炸应力波进行测定的结果。     

一步法合成(E)-1,3-二取代丙-2-烯-1-酮类化合物

报道了一种温和的,以二氧化锰为氧化剂,通过串联氧化反应-Wittig反应-氧化反应,一步制备(E)-1,3-二取代丙-2-烯-1-酮类化合物的合成方法。使用该方法,我们合成7个具有代表性的化合物。     

浅析国际工程承包合同的风险管控

总结了国际工程承包合同模式及其主要条款的基本组成,概括了国际工程承包合同条款的组合特征和和风险点识别要素;针对项目管理的全过程控制,描述了合同管理的主要内容、基本要求,并进行风险点梳理;针对合同中的主要风险条款,研究分析了其风险要素,提出了防范和规避风险的具体措施。     

Hydrothermally stable mesoporous aluminosilicates with moderate acidity via degradation-assembly process and improved catalytic properties

Mesoporous aluminosilicates with hydrothermal stability and moderate acidity are synthesized via assembly of microporous zeolite precursors obtained by the degradation of zeolite NaY, denoted as “degradation-assembly” (DA) technique. By controlling the degradation degree of matrix NaY, precursors with larger spatial volume and stronger rigidity will be obtained. The characterization results showed that the walls of the mesophase in MDA (mesoporous aluminosilicate obtained by “DA” method) composed of the preformed zeolite Y building units and the moderate acidity was inherited from the introduced precursors. It was suggested that the more mature assembly units accounted for the increased acidity of MDA with more Al species retained in the framework of mesophases. The resulting aluminosilicates with simultaneously moderate acidity and hydrothermal stability showed superior catalytic properties when used in heavy oil catalytic cracking catalysts.     

Performance evaluation of asphalt containing layered double hydroxides with different zinc ratio in the host layer

The effects of five layered double hydroxides (LDHs) with different zinc ratio on the physical and rheological properties, chemical components, and anti-UV aging performance of asphalt were evaluated. Results show that LDHs improve the deformation resistance of asphalt at high temperature. After UV aging, LDH-modified asphalts show the smaller changes of physical and rheological properties and chemical components in comparison with asphalt, indicating the improved UV aging resistance. By comparison, the LDHs with higher ratio of zinc in the layers have the more outstanding UV reflection ability, leading to a beneficial effect in improving UV aging resistance of asphalt.     

Palladium and Copper Cocatalyzed Intermolecular Cyclization Reaction: Synthesis of 5‐Aminopyrazole Derivatives

A novel and efficient palladium and copper co‐catalyzed intermolecular cyclization of acetonitriles with hydrazones has been developed for the synthesis of 5‐aminopyrazoles through C C and C N bond formation. The reaction has the advantages of easily available starting materials, simple manipulation and mild reaction conditions. The reaction involving various substituted acetonitriles and hydrazones proceeds smoothly and 5‐aminopyrazoles are synthesized in good yields. In contrast to the aliphatic and heteroaromatic substrates, the aromatic substrates tend to have a higher degree of reactivity.

     

Dearomatization of Indole Derivatives via Palladium‐Catalyzed C?H Bond Functionalization of Pyrroles: Convenient Construction of Spiroindolenines

An intramolecular palladium(II)‐catalyzed dearomative arylation reaction of indoles via C H bond functionalization was developed, providing access to structurally novel spiroindolenines with moderate to good yields. A one‐pot process for the synthesis of spiroindoline derivatives was also realized.