The structure optimization of tracked ambulance nonlinear vibration reduction system

Xinxi Xu,Meng Yang,Nan Jia,Deguang Duan 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

Our aim was to improve the performance of tracked ambulance nonlinear vibration reduction system by structure optimization design. The structure optimization focuses on the stretcher base. Two structure optimization schemes are proposed based on the mechanism of Dynamic vibration absorber (DVA): Linear and nonlinear structure. The linear structure optimization scheme is finally adopted by comparison of the two schemes under random vibration, and the performance of linear scheme is also verified under shock vibration. Then the global sensitivity analysis method is applied to calculate the parameter sensitivity of nonlinear vibration reduction system. Finally, the Nondominated sorting genetic algorithm II (NSGA-II) is used to optimize the performance of the nonlinear vibration reduction system. It shows that the vibration energy of the supine human body on a stretcher is reduced after above studies, which proves the validity and feasibility of the structure optimization schemes proposed and the optimization studies applied in this paper.

国有企业招待费异化的法律规制 -以国有企业治理的完善为视角

Xiao Xinxi(肖新喜) 충북대학교 법학연구소 2014 法學硏究 Vol.25 No.1

The sky-high entertainment expense reflects a dissimilation mode of state-owned enterprise's entertainment expense, which is ruinous. For that matter, china must eliminate the dissimilation phenomenon of state-owned enterprise's entertainment expense. The reason of this phenomenon is state-owned enterprises' incomplete management. The particularity of state-owned enterprise property rights lead to its incomplete inner management structure and external management failed to meet the requirements of the market mechanism. In order to solve this problem, there are many measures must be taken in legislation of state-owned enterprise and corporation: a) to make clear definitions about state-owned enterprises' criteria and range; b) to make clear regulations about state-owned enterprise's entertainment expense; c) to improve the democratic management system; d) to build scientific reasonable information disclosure system e) to strengthen accountability mechanism. 天价招待费的出现表明我国国有企业招待费存在某种形式的异化,其危害极大。就此而言,国家必须消除国有企业招待费异化的现象。招待费异化的原因在于国有企业治理的不完善:国有企业产权特殊性导致的内部治理结构不健全以及外部治理不符合市场机制的要求。要解决国有企业招待费异化问题,我国国有企业立法以及公司立法必须采取以下措施:明确规定国企招待费的标准与范围;明确规定国企高管的招待费滥用义务;完善国企的民主管理制度;构建合理科学的信息公开制度;强化责任追究机制。

An Improved LLC Resonant Converter with Variable-Rectifier for Electric-Vehicle Charger Application

Jian Zhao,Xinxi Tang,Hongfei Wu,Yan Xing,Kai Sun 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

An improved LLC converter with variablerectifier (VR) is studied and evaluated for electric-vehicle charger applications with wide output voltage range. The VR can be reconfigured as center-tapped rectifier (CTR) and full-bridge rectifier (FBR) by the secondary side auxiliary switches. The output voltage range is extended by changing the configuration of rectifier, which results in reduced switching frequency range, circulating current, and conduction losses. Meanwhile, zero voltage switching are achieved for all MOSFETs. A mode transition scheme is employed to achieve smooth and fast transition between CTR and FBR modes. The operation principles are analyzed in detail. A 500W prototype with 400V input voltage and 40-160V output voltage is built and tested to verify the feasibility of the converter.

Study on the Fracture Properties of the PMMA Structure for the JUNO Central Detector

Zongyi Wang,Yuanqing Wang,Xinxi Du,Tianxiong Zhang,Yuekun Heng 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.6

Polymethyl methacrylate (PMMA) is increasingly used in building structures nowadays. PMMA materials utilized in structures have different fracture property compared with those used in aircrafts or biomedical equipment. Single-edge-notch bending (SENB) tests were firstly carried out at various temperatures (-40°C, -20°C, 0°C, 20°C, and 40°C) to determine the KIC values of base PMMA materials and connected areas. The crack-resisting capacity of PMMA plate is subsequently studied. The fracture property of the PMMA joint for the Jiangmen Underground Neutrino Observatory (JUNO) central detector is investigated. The results show that base PMMA material has higher KIC values than connected area. The KIC of base PMMA material is lowest at 20°C and highest at -20°C, while that of connected area is lowest at 40°C and highest at -40°C. For the PMMA joint of the JUNO detector, the cracks perpendicular to the X axis are more disadvantageous than those perpendicular to the Z axis. The stress intensity factors (SIFs) at the crack front of the embedded crack decrease with the increase of embedded depth. Due to the presence of two parallel surface or embedded cracks, the SIFs at the crack front decrease.

Simultaneous removal of SO2 and NOX with ammonia absorbent in a packed column

Yong Jia,Daqian Du,Xinxi Zhang,Xilou Ding,Oin Zhong 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.9

Catalytic oxidation of NO followed by simultaneous removal of SO2 and NOX with ammonia is a promising method for control of coal-fired flue gas pollutants. We investigated simultaneous absorption of SO2 and NOX in a packed column with ammonia, and found that SO2 and NOX could promote absorption with each other in the process of simultaneous removal SO2 and NOX. The removal efficiency of SO2 and NOX was, respectively, about 98% and 70.9% at pH 5.5, temperature 323.15 K, SO2 concentration 1,800×10−6, NOX concentration 400×10−6 and mNO2/mNO 1 in our experimental system. The experimental results also show that the formation of sulfite oxidized by reacting with dissolved NO2and the molar ratio of sulfite to total sulfur is more than 0.8 in the solution. Accordingly, the energy consumption for sulfite oxidation would be greatly reduced in the process of simultaneous desulfurization and denitrification with ammonia.

Continuous W Cu functional gradient material from pure W to W Cu layer prepared by a modified sedimentation method

Wei Bangzheng,Zhou Rui,Xu Dang,Chen Ruizhi,Yu Xinxi,Chen Pengqi,Cheng Jigui 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.12

The thermal stress between W plasma-facing material (PFM) and Cu heat sink in fusion reactors can be significantly reduced by using a WeCu functionally graded material (WeCu FGM) interlayer. However, there is still considerable stress at the joining interface between W and WeCu FGM in the W/WeCu FGM/Cu portions. In this work, we fabricate W skeletons with continuous gradients in porosity by a modified sedimentation method. Sintering densification behavior and pore characteristics of the sedimented W skeletons at different sintering temperatures were investigated. After Cu infiltration, the final WeCu FGM was obtained. The results indicate that the pore size and porosity in the W skeleton decrease gradually with the increase of sintering temperature, but the increase of skeleton sintering temperature does not reduce the gradient range of composition distribution of the final prepared WeCu FGM. And WeCu FGM with composition distribution from pure W to W-20.5wt.% Cu layer across the section was successfully obtained. The thickness of the pure W layer is about one-fifth of the whole sample thickness. In addition, the prepared WeCu FGM has a relative density of 94.5 % and thermal conductivity of 185 W/ (m K). The WeCu FGM prepared in this work may provide a good solution to alleviate the thermal stress between W PFM and Cu heat sink in the fusion reactors.

Fabrication of diamond/W – Cu functionally graded material by microwave sintering

Chenlong Wei,Jigui Cheng,Mei Zhang,Rui Zhou,Bangzheng Wei,Xinxi Yu,Laima Luo,Pengqi Chen 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.3

A four-layered W/Cu functionally graded material (FGM) (W90% þ Cu10%/W80% þ Cu20%/W70% þ Cu30%/W60% þ Cu40%, wt.% fraction) and a four-layered diamond/WeCu FGM (W90% þ Cu10%/W80% þ Cu20%/W70% þ Cu30%/W55% þ Cu40% þ diamond5%, wt.% fraction) were fabricated by microwavesintering. The thermal conductivity and thermal shock resistance of diamond/WeCu FGM andWeCu FGM were investigated. The morphologies of the diamond particles and different FGMs wereanalyzed using AFM, SEM, EDS, and TEM. The results show that a 200 nm rough tungsten coating wasformed on the surface of the diamond. The density of the tungsten-coated diamond/WeCu FGM, obtainedby microwave sintering at 1200 C for 30 min, was 94.66%. The thermal conductivity of the fourlayereddiamond/WeCu FGM was 220 W$m-1$K-1, which is higher than that of the four-layered W/CuFGM (209 Wm 1 K 1). This indicates that adding an appropriate amount of tungsten-coated diamond tothe high Cu layer W/Cu FGM improves the thermal conductivity of the composite. The diamond/WeCuFGM sintered at 1200 C for 10 min exhibited better thermal shock resistance than diamond/WeCu FGMsintered at 1100 C for 10 min