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Analysis of Thermoelastohydrodynamic Performance of Journal Misaligned Engine Main Bearings

Chinese Journal of Mechanical Engineering 2015年第3期28卷 511-520页

作者： BI Fengrong SHAO Kang liu changwen WANG Xia ZHANG Jian State Key Laboratory of Engines Tianjin University

To understand the engine main bearings＇ working condition is important in order to improve the performance of engine. However, thermal effects and thermal effect deformations of engine main bearings are rarely considered simultaneously in most studies. A typical finite element model is selected and the effect of thermoelastohydrodynamic（TEHD） reaction on engine main bearings is investigated. The calculated method of main bearing＇s thermal hydrodynamic reaction and journal misalignment effect is finite difference method, and its deformation reaction is calculated by using finite element method. The oil film pressure is solved numerically with Reynolds boundary conditions when various bearing characteristics are calculated. The whole model considers a temperature-pressure-viscosity relationship for the lubricant, surface roughness effect, and also an angular misalignment between the journal and the bearing. Numerical simulations of operation of a typical I6 diesel engine main bearing is conducted and importance of several contributing factors in mixed lubrication is discussed. The performance characteristics of journal misaligned main bearings under elastohydrodynamic（EHD） and TEHD loads of an I6 diesel engine are received, and then the journal center orbit movement, minimum oil film thickness and maximum oil film pressure of main bearings are estimated over a wide range of engine operation. The model is verified through the comparison with other present models. The TEHD performance of engine main bearings with various effects under the influences of journal misalignment is revealed, this is helpful to understand EHD and TEHD effect of misaligned engine main bearings.

关键词： main bearings journal misaligned oil film pressure Reynolds equation finite difference methods thermoelastohydrodynamic(TEHD)

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Experimental study of the influence of a pour point depressant additive on particle size distributions in diesel engine exhausts

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Particuology 2014年第2期12卷 73-81页

作者： Xingyu Liang Yuesen Wang Lihui Dong Gequn Shu changwen liu State Key Laboratory of Engines Tianjin University

Many studies have been performed on diesel engine particulate matter emissions, but the influence of lubricants on emissions has only been considered a few times, and the effects of lubricant additives have yet to be investigated. We studied the influence of a pour point depressant additive （PPD） on particle emissions and particle size distributions from a four-cylinder turbocharged, inter-cooled engine with CF-4 15W-40 lubricant, using diesel or diesel containing the PPD, Changing the working conditions changed the number of particles emitted and the location of the peak particle size（s） emitted, The number of particles first increased and then decreased as the engine speed increased, Particle emissions were optimal at low engine speeds and high load, increasing with increasing engine speed,

关键词： DieselPPDParticulate matterParticle emissionDistribution of particles

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DESIGN AND ANALYSIS OF NOVEL ACTIVE ACTUATOR TO CONTROL LOW FREQUENCY VIBRATIONS OF SHAFT SYSTEM

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Chinese Journal of Mechanical Engineering 2008年第6期21卷 41-47页

作者： YU Yilong liu changwen YANG Yanxiang WANG Shuang ZHANG Junhong State Key Laboratory of Engines School of Mechanical Engineering Tianjin University Tianjin 300072 China Tianjin Internal Combustion Engine Research Institute Tianjin University Tianjin 300072 China

Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrations is designed. The actuator employs electro-hydraulic system and can provide a high and circumferential load. To initialize new research, the characteristics of various kinds of active actuators to control rotor shaft vibration are briefly introduced. The purpose of this paper is to introduce the preliminary results via presenting the structure, functions and operating principles, in particular, the working process of the electro-hydraulic system of the new actuator which includes a set of high speed electromagnetic valves and a series of sloping cone-shaped openings, and presenting the transmission relationships among the control parameters from control signals into the valves to active load onto shaft. The course of the work is dynamic, and a series of spatial forces and moments are put on the shaft to get an external resultant force to reduce excitations that induce vibration of shafts. By checking states of vibration, the actuator can control the impulse width and the interval of injection time for applying different control force to a vibration shaft in two circumference directions through the regulating action of a set of combination directional control valves. The results from simulating analysis and experiment show evidence of that this design can satisfy the case of active process of decreasing of flexural and torsional vibrations.

关键词： Actuators Low frequency vibration Active control Large-scale rotation shafts System development

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Low temperature surface oxygen activation in crystalline MnO_(2) triggered by lattice confined Pd single atoms

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Journal of Energy Chemistry 2021年第11期30卷 136-144,I0003页

作者： Xuemei Liao Yonghui Zhao changwen liu Xiaopeng Li Yu Sund Kenichi Kato Miho Yamauchi Zheng Jiang College of Food and Biological Engineering Xihua UniversityChengdu 610039SichuanChina CAS Key Laboratory of Low-Carbon Conversion Science and Engineering Shanghai Advanced Research Institute(SARI)Chinese Academy of Sciences(CAS)No.100Haike RoadPudong New DistrictShanghai 201210China State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityNo.2999 North Renmin RoadSongjiang DistrictShanghai 201620China Institute for the Advancement of Higher Education Hokkaido UniversitySapporo 060-0817Japan Department of Chemistry Faculty of ScienceHokkaido UniversityN10W8Kita-kuSapporoHokkaido 060-0810Japan RIKEN SPring-8 Center1-1-1 KoutoSayo-choSayo-gunHyogo 679-5148Japan International Institute for Carbon-Neutral Energy Research(WPI-I2CNER) Kyushu UniversityMotooka 744Nishi-kuFukuoka 819-0395Japan Advanced Institute for Materials Research(AIMR) Tohoku University2-1-1 KatahiraAoba-kuSendai 980-8577Japan Shanghai Synchrotron Radiation Facility Zhangjiang LabShanghai Advanced Research Institute(SARI)Chinese Academy of Sciences(CAS)No.239 Zhangheng RoadPudong New DistrictShanghai 201203China Shanghai Institute of Applied Physics Chinese Academy of ScienceNo.2019 Jia Luo RoadJiading DistrictShanghai 201800China

Tuning the coordination environment is the research axis of single atom catalysts (SACs). SACs are commonly stabilized by various defects from support. Here, we report a lattice confined Pd SAC using MnO_(2) as support. Compared with the Pd clusters anchored on the surface, the lattice confined Pd single atoms allows spontaneous exaction of surrounding lattice oxygen at room temperature when employed in CO oxidation. The MnO_(2) supported Pd SAC exhibited a high turnover frequency of 0.203 s^(−1) at low reaction temperature, which is higher than that of recently reported Pd SACs. Theoretical calculations also confirmed the confined monatomic Pd activate lattice oxygen with an ultralow energy barrier. Our results illustrate that the unique coordination environment of single atom provided by lattice confinement is promising to boost the activity of SACs.

关键词： Single atom catalysts(SACs) Lattice confinement Oxygen activation Manganese oxide nanofiber

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Simplified Compact Perovskite Solar Cells with Efficiency of 19.6% via Interface Engineering

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Energy & Environmental Materials 2020年第1期3卷 5-11页

作者： Dedi Li changwen liu Shi Chen Weiguang Kong Haichao Zhang Deng Wang Yan Li Jianhui Chang Chun Cheng Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Shenzhen Engineering Research and Development Center for Flexible Solar Cells Southern University of Science and TechnologyShenzhen 518055China Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhen Guangdong Province 518055China Guangdong Provincial Key Laboratory of Energy Materials for Electric Power Southern University of Science and TechnologyShenzhen 518055China

For the commercialization of perovskite solar cells(PSCs), it is more appealing to develop high-performance simplified PSCs where perovskite films are just sandwiched between the back and front electrodes, in order to simplify the fabrication process and to reduce the cost. However, to date, this kind of devices shows rather low performance, and there are few researches on this ***, we report on a kind of compact PSCs(CPSCs) that are free of independent charge transport layers(CTLs). The devices are realized by the use of organic monolayer-modified effective electrodes, along with the use of [6,6]-phenyl-C61-butyric acid methyl ester(PCBM)-assisted anti-solvent technique to obtain ultra-thin(~10 nm) PCBM-embedded perovskite films. Compared to control devices, CPSCs achieve a promising champion power conversion efficiency of 19.6% with largely reduced hysteresis. Moreover, the unencapsulated CPSC shows good stability under ambient atmosphere, with only 10% efficiency loss after 60 days’ storage. This work indicates that, by delicate design, CPSCs with smaller materials consumption in device architecture can perform competitively as conventional PSCs. Further reduction in the actual usage of costly CTL materials can be expected upon our CPSCs by developing more facile and economic methods to prepare ultra-thin CTLs.

关键词： charge transport layers compact perovskite solar cells interface engineering monolayer-modified electrodes ultra-thin

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Preparation and Characterization of Heteropoly Octadecamolybdodiphosphates

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Chemical Research in Chinese Universities 1991年第1期7卷 6-10页

作者： Wang Enbo, You Wansheng, liu Jingfu, Hu changwen Zhang Baojian (Department of Chemistry, Northeast Normal University, Changchun)

Heteropoly molybdophosphates with general formula M(?)P2Mo18O62 ·xH2O, where M = H+, K+, NH4+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+ and Ag+, were prepared and characterlzed by elemental analysis, IR and UV spectrometry and thermal analysis. The solubilities of the compounds were examined. The IR spectra show that the countercations and the crystallization water have an influence upon the vibration frequencies of vMo-Oc and vMo-Oc-Mo·In the UV spectra, the charge-transfer bands are assigned to e→e and e→b2 transition. All the compounds decompose at 328-534℃.

关键词： Preparation Heteropoly molybdophosphates Formula

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Breeding of a Natural Green Cocoon Quaternary Hybrid Combination Xiangcailu No.1 for Spring Rearing

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Agricultural Biotechnology 2019年第4期8卷 14-18,25页

作者： Hong XUE Junwen AI Yanghu SIMA Xingjian HE changwen liu Ying ZHENG Yong liu Yun TANG Sericultural Research Institute of Hunan Province Changsha 410127China Soochow University Suzhou 215123China

The breeding activities aimed to create a natural green cocoon variety for spring rearing with the characteristics of stable natural cocoon color,easy rearing and good silk *** different lines from the excellent silkworm variety Jingsong×Haoyue were taken as recurrent parents,using the natural green cocoon variety G 9202 as donor *** other excellent parents were introduced to cross with these different lines,four new breeding materials were selected by recurrent backcross *** characters of these breeding materials showed not only natural green cocoon but also excellent comprehensive traits.A naturally colored cocoon quaternary hybrid with excellent practical characters was selected based on multiple *** is suitable for spring rearing in Yangtze valley which includes Hunan *** was approved by Hunan Provincial Crop Variety Approval Committee and designated Xiangcailu No.1 in 2016.

关键词： Silkworm Xiangcailu No.1 Recurrent backcross breeding Natural green cocoon Spring rearing Easy rearing Excellent silk quality

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引燃油喷射时刻对着火特性和压力振荡影响的研究

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天津大学学报（自然科学与工程技术版） 2020年第2期53卷 154-161页

作者：刘昌文刘宗宽刘博周磊卫海桥天津大学内燃机燃烧学国家重点实验室天津300072 中船动力研究院有限公司上海201206

为提高天然气/柴油双燃料船用低速发动机低负荷时的燃烧稳定性、避免高负荷时爆震发生,采用三维数值模拟的方法,研究了实际双燃料发动机中引燃油喷射时刻对缸内混合气的着火/燃烧特性及缸内压力振荡的影响.结果表明:甲烷当量比为0.38的... 详细信息

为提高天然气/柴油双燃料船用低速发动机低负荷时的燃烧稳定性、避免高负荷时爆震发生,采用三维数值模拟的方法,研究了实际双燃料发动机中引燃油喷射时刻对缸内混合气的着火/燃烧特性及缸内压力振荡的影响.结果表明:甲烷当量比为0.38的工况,引燃油喷射时刻的推迟会造成缸内甲烷/空气混合气的着火时刻和燃烧相位推迟,缸内压力减小且爆压相位滞后;当喷射时刻推迟至2.0°CA BTDC时,缸内压力峰值低于10 MPa,说明燃烧严重恶化,甚至出现失火现象.甲烷当量比为0.50的工况,引燃油喷射时刻的推迟使缸内压力振荡幅度增大且振荡发生的时刻推迟,当喷油时刻推迟至2.0°CA BTDC时,甲烷/空气混合气在引燃油喷射之前发生自燃;此外,喷油时刻的推迟会导致火焰发展速度加快且火焰前端燃烧更为剧烈,易在靠近壁面的狭小空间内产生压力振荡.

关键词：双燃料引燃油喷射时刻着火特性压力振荡

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二维计数跟踪型激光多普勒测速研究

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中国激光 1999年第12期26卷 1118-1122页

作者：刘昌文刘杰孙其超王仕康天津大学机械工程学院汽车工程系天津300072

二维计数跟踪型激光多普勒测速系统利用两个计数跟踪光电混合反馈环路来分离并测量速度的二维分量。采用计数跟踪方法后,光电信号的带宽被压缩了至少一个数量级,使得该系统不仅工作稳定可靠,而且结构简单、成本低廉。详细讨论该系统的... 详细信息

二维计数跟踪型激光多普勒测速系统利用两个计数跟踪光电混合反馈环路来分离并测量速度的二维分量。采用计数跟踪方法后,光电信号的带宽被压缩了至少一个数量级,使得该系统不仅工作稳定可靠,而且结构简单、成本低廉。详细讨论该系统的工作原理、构成,并给出实验研究结果。

关键词：激光多普勒测速激光测速计数跟踪技术

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基于信号分析的发电机组辐射噪声盲源分离和识别

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内燃机工程 2017年第2期38卷 141-145页

作者：景亚兵刘昌文毕凤荣天津大学内燃机燃烧学国家重点实验室天津300072 天津大学内燃机研究所天津300072

具有独立分量的经验模态分解算法结合了独立成分分析算法和经验模态分解算法的优点,可通过单个观测信号将噪声源分解成一系列独立分量,保证了分离出的声源的独立性,同时利用小波变换技术对各个独立分量进行了分析,通过时频分析结果确定... 详细信息

具有独立分量的经验模态分解算法结合了独立成分分析算法和经验模态分解算法的优点,可通过单个观测信号将噪声源分解成一系列独立分量,保证了分离出的声源的独立性,同时利用小波变换技术对各个独立分量进行了分析,通过时频分析结果确定了各独立分量与发电机组各噪声源的对应关系,并通过试验进行了验证。研究结果表明:这些独立分量分别对应着配气机构噪声、平衡轴驱动齿轮噪声、正时齿轮噪声和进气噪声。

关键词：内燃机发电机组盲源分离独立成分分析经验模态分解小波变换

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