Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system

Computational Fluid Dynamics (CFD) simulations of cavitating flow through water hydraulic poppet valves were performed using advanced RNGk-epsilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reynolds numbers greater than 43000. The working fluid was water, and the structure of the valve was simplified as a two dimensional axisymmetric geometrical model. Flow field visualization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as well as poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera. The binary cavitating flow field distribution obtained from digital processing of the original cavitation image showed a good agreement with the numerical result. Project supported by the National Natural Science Foundation of China (No. 59835160) and Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry of China (No. 50175097)     

基于供需平衡理论对辽宁本科英语翻译专业发展问题的必要性研究

本论文围绕基于供需平衡视角下的辽宁高校英语翻译专业发展现状和提升路径两部分展开。本论文拟从教育学、社会学和管理学的视角审视目前辽宁高校英语翻译专业存在的问题。本研究主要是在借鉴教育经济学中人才供需理论的基础上,深入挖掘辽宁高校英语翻译专业自身的特点与性质以及市场供需之间的关系,以供需平衡的视角应对目前英语翻译专业发展的困境,进而找到优化学科发展,提升学生就业能力的路径。     

教学投影机亮度变暗的解决方案

对投影机亮度变暗的原因与维修、维护的范围及效果进行了分析，提出了维护、维修的方案及成本预测。     

做专家型的员工

每到年终的时候，当老板的总是要给优秀员工发一个大大的红包，这时做老板的常常会有类似的感慨：要是企业里的员工都能像小王一样，该多好啊，我们企业将会有多大的发展啊。而业绩落在小王后面的小李小赵也会在心里暗自思忖：我什么时候也能做到他那么好的表现呢?     

Clinical detection and movement recognition of neuro signals

INTRODUCTION Human limbs are complex, delicate systems.Their reconstruction, both for appearance and forfunction compensations, proves to be complicatedprojects. With the development of science and tech-nology, both researchers and disabilities hope to haveartificial limb much more perky, comfortable, dex-terous and effective. Although thousands of pros-thetic limbs are commercially available worldwide,most of them, from mechanical styles to electricstyles, from motion controlled t…     

关于解决乳化炸药发泡后效方法的分析

乳化炸药生产中采用的化学发泡敏化方式，往往会产生后效问题，给产品的质量带来很大的影响，提出了对克服发泡后效的方法，并对其进行了理论上的分析论证，通过生产中的实验，证明是切实可行的，并对生产工艺进行了调整，解决了发泡后效问题，提高了产品质量，取得了良好的效果。     

Tandem Biocatalysis by CotA-TJ102@UIO-66-NH2 and Novozym 435 for Highly Selective Transformation of HMF into FDCA

2,5-Furandicarboxylic acid(FDCA) is a potential biorenewable chemical for applications including plastics, polyamides, drugs, etc. The selective biosynthesis of FDCA from 5-hydroxymethylfurfural(HMF) by a specific enzyme poses a great challenge. In this study, we reported an efficient strategy to produce FDCA from HMF by the tandem biocatalysis of laccase(Cot A-TJ102@UIO-66-NH_2) and Novozym 435. For the first step, a nanoparticle metal–organic framework was synthesized as a carrier to immobilize Cot A-TJ102@UIO-66-NH_2, which was assigned for the production of 5-formyl-2-furancarboxylic acid(FFCA) and featured an enzyme loading of 255.54 mg/g, specific activity of 135.90 U/mg, and solid loading ratio of 99.65%. Under optimal conditions, an ideal FFCA yield of 98.5% was achieved, and the Cot A-TJ102@UIO-66-NH_2 presented a high recycling capacity after 10 cycles. For the second step, Novozym 435 was applied for the further conversion of FFCA into FDCA, presenting a high FDCA yield of 95.5% under the optimized conditions. Novozym 435 also exhibited a high recyclability after eight cycles. As a result, the tandem biocatalysis strategy provided a 94.2% FDCA yield from HMF, indicating its excellence as a method for FDCA production.     

论邓小平关于实践主体的思想

邓小平同志实践主体的思想强调了实践主体人的“现代化”，强调了改革开放实践中，“人民群众是社会历史活动主人”的观点，强调了改革开放实践目的的“人民性”－以“是否有利于提高人民生活水平”作为判定改革开放的一个重要标准。     

谈谈声乐表演专业学生的嗓音保护

透视当前嗓音保护的现象,阐述了嗓音保护的重要性,并结合教学实践,提出了一些保护嗓音的可行性方法.     

新课改背景下的高中物理课堂教学设计

在我市新课程实施的初期阶段,笔者根据自己的教学经验,结合新课程所倡导的一些基本理念,对课堂教学设计进行了改进,以期与广大一线教师进行交流。