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Nonlinear vibration response characteristics of a dual-rotor-bearing system with squeeze film damper

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Chinese Journal of Aeronautics 2021年第10期34卷 128-147页

作者： Xinxing MA Hui MA Haiqin QIN Xumin GUO chenguang zhao Mingyue YU School of Mechanical Engineering and Automation Northeastern UniversityShenyang J10819China Institute of Vibration Shock and NoiseShanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of Vibration and Control of Aero-Propulsion System Ministry of Education Northeastern UniversityShenyang 110819China Department of Aeronautical Mechanics Naval Aeronautical and Astronautical University Qingdao CampusQingdao 266041China

Rolling bearing and Squeeze Film Damper(SFD)are used in rotor support structures,and most researches on the nonlinear rotor-bearing system are focused on the simple rotor-bearing systems.This work emphasizes the comparative analysis of the influence of SFD on the nonlinear dynamic behavior of the dual-rotor system supported by rolling bearings.Firstly,a reduced dynamic model is established by combining the Finite Element(FE)method and the freeinterface method of component mode synthesis.The proposed model is verified by comparing the natural characteristics obtained from an FE model with those from the experiment.Then,the steady-state vibration responses of the system with or without SFD are solved by the numerical integration method.The influences of the ball bearing clearance,unbalance,centralizing spring stiffness and oil film clearance of SFD on the nonlinear steady-state vibration responses of the dual-rotor system are analyzed.Results show that SFD can effectively suppress the amplitude jump of the dual rotor system sustaining two rotors unbalance excitations.As the ball bearing clearance or unbalance increases,the amplitude jump phenomenon becomes more obvious,the resonance hysteresis phenomenon strengthens or weakens,the resonant peaks shift to the left or the right,respectively.SFD with unreasonable parameters will aggravate the system vibration,the smaller the oil film clearance,the better the damping performance of the SFD,the larger the centralizing spring stiffness is,the larger resonance amplitudes are.

关键词： dual-rotor rolling bearing squeeze film damper finite element method vibration response

Dynamic characteristics of a shrouded blade with impact and friction

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Frontiers of Mechanical Engineering 2020年第2期15卷 209-226页

作者： Xumin GUO Jin ZENG Hui MA chenguang zhao Lin QU Bangchun WEN School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Key Laboratory of Vibration and Control of Aero-Propulsion System Ministry of Education Northeastern UniversityShenyang 110819China

A simplified computational model of a twisted shrouded blade with impact and friction is established.In this model,the shrouded blade is simulated by a flexible Timoshenko beam with a tip-mass,and the effects of centrifugal stiffening,spin softening,and Coriolis force are considered.Impact force is simulated using a linear spring model,and friction force is generated by a tangential spring model under sticking state and a Coulomb friction model under sliding state.The proposed model is validated by a finite element model.Then,the effects of initial gap and normal preload,coefficient of friction,and contact stiffness ratio(the ratio of tangential contact stiffness to normal contact stiffness)on system vibration responses are analyzed.Results show that resonant peaks become inconspicuous and impact plays a dominant role when initial gaps are large between adjacent shrouds.By contrast,in small initial gaps or initial normal preloads condition,resonant speed increases sharply,and the optimal initial normal preloads that can minimize resonant amplitude becomes apparent.Coefficient of friction affects the optimal initial normal preload,but it does not affect vibration responses when the contact between shrouds is under full stick.System resonant amplitude decreases with the increase of contact stiffness ratio,but the optimal initial normal preload is unaffected.

关键词： twisted shrouded blade dynamic analysis impact friction separate-stick-slip motion

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“金砖”扩容与非洲参与全球治理机制化探析

中国非洲学刊 2024年第1期5卷 3-18,144页

作者：赵晨光外交学院非洲研究中心北京100037

非洲参与全球治理机制化主要是指非洲大陆及非洲主要国家在全球治理体系中身份、角色和地位的规范化、规则化和制度化。21世纪以来,非洲参与全球治理机制化取得较大进展。在此背景下,金砖合作机制开启对非扩容进程,对非议题领域不断拓... 详细信息

非洲参与全球治理机制化主要是指非洲大陆及非洲主要国家在全球治理体系中身份、角色和地位的规范化、规则化和制度化。21世纪以来,非洲参与全球治理机制化取得较大进展。在此背景下,金砖合作机制开启对非扩容进程,对非议题领域不断拓展、议题设置实现“非洲化”、与非洲关系不断“议题化”。金砖合作机制对非扩容可以视为非洲参与全球治理走向机制化的标志和缩影,具有深远意义。在非洲实质性参与全球治理的进程中,中国与非洲合作发挥了积极作用。未来的对非合作,中国需要进一步关注和回应非洲在提升全球治理代表性、话语权方面的诉求;通过加强治国理政经验交流、对非合作机制建设以及探索对非机制性三方合作等方式,发掘新的中非合作增长点,助力非洲提升参与全球治理的经验和能力。

关键词：金砖合作机制金砖对非扩容全球治理中非合作

中国水资源行为二氧化碳排放当量及空间非均衡性

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水资源保护 2024年第2期40卷 72-80页

作者：蒋国栋左其亭赵晨光马军霞张志卓郑州大学水利与交通学院河南郑州450001 河南省水循环模拟与水环境保护国际联合实验室河南郑州450001

采用二氧化碳排放当量分析(CEEA)方法计算了中国除港澳台外的31个省级行政区涉及水资源开发、配置、利用与保护4个维度的16种水资源行为二氧化碳排放当量(CEE),并基于Dagum基尼系数探究了中国水资源行为CEE的空间非均衡性及其来源。结... 详细信息

采用二氧化碳排放当量分析(CEEA)方法计算了中国除港澳台外的31个省级行政区涉及水资源开发、配置、利用与保护4个维度的16种水资源行为二氧化碳排放当量(CEE),并基于Dagum基尼系数探究了中国水资源行为CEE的空间非均衡性及其来源。结果表明:2020年中国水资源行为CEE总量为13 819.84万t,开发、配置、利用与保护4个维度水资源行为CEE总量分别为21 297.68万、4 371.45万、-3 141.71万、-8 707.58万t;水资源行为CEE整体呈现出由东向西递减的空间分布规律,江苏和广东是水资源行为CEE最大的省份;多数水资源行为CEE具有较强的空间非均衡性,其中水力发电行为CEE的Dagum基尼系数为0.73,其CEE空间非均衡性最强,地区间净值差异是水资源行为CEE空间非均衡性的主要贡献因素。

关键词：水资源行为碳中和二氧化碳排放当量 Dagum基尼系数空间非均衡性

Recombinant adenovirus-mediated overexpression of 3β-hydroxysteroid-Δ24 reductase

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Neural Regeneration Research 2014年第5期9卷 504-512页

作者： Xiuli Lu Dan Jia chenguang zhao Weiqi Wang Ting Liu Shuchao Chen Xiaoping Quan Deliang Sun Bing Gao Department of Biochemistry and Cell Biology School of Life ScienceLiaoning University Department of Cell Biology and Genetics School of Basic Medical Sciences Shenyang Medical College

3β-Hydroxysteroid-△24 reductase （DHCR24） is a multifunctional enzyme that localizes to the endoplasmic reticulum and has neuroprotective and cholesterol-synthesizing activities. DHCR24 overexpression confers neuroprotection against apoptosis caused by amyloid β deposition. The present study aimed to construct two recombinant adenoviruses driving DHCR24 expression specifically in neurons. Two SYN1 promoter DNA fragments were obtained from human （h） and rat （r）. Recombinant Ad-r（h）SYN1-DHCR24 was transfected into AD-293, N2A （mouse neuroblastoma）, and MIN6 （mouse pancreatic carcinoma） cells. Western blot analysis showed DHCR24 was specially expressed in 293 and N2A cells, but no specific band was found in MIN6 cells. This demonstrates that the recombinant adenoviruses successfully express DHCR24, and no expression is observed in non-neuronal cells. TUNEL assay results showed apoptosis was inhibited in adenovirus-transfected neurons. Detecting reactive oxygen species by immunoflu- orescence, we found that adenovirus transfection inhibits apoptosis through scavenging excess reactive oxygen species. Our findings show that the recombinant DHCR24 adenoviruses induce neuron-specific DHCR24 expression, and thereby lay the foundation for further studies on DHCR24 gene therapy for Alzheimer＇s disease.

关键词： nerve degeneration 3β-hydroxysteroid-△ 2 4 reductase recombinant adenovirus neuron oxidative stress synapsin-1 gene therapy neuroprotection NSFC grant neural regeneration

Texturization and rounded process of silicon wafers for heterojunction with intrinsic thin-layer solar cells

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Frontiers of Optoelectronics 2014年第1期7卷 46-52页

作者： Kunpeng MA Xiangbin ZENG Qingsong LEI Junming XUE Yanzeng WANG chenguang zhao School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 China Shenzhen Institute of Huazhong University of Science and Technology Shenzhen 518000 China Hisunpv Technology Co. Ltd Hebei 053000 China

Heterojunction with intrinsic thin-layer （HIT） solar cells are sensitive to interface state density. Tradi- tional texture process for silicon solar cells is not suitable for HIT one. Thus, sodium hydroxide （NaOH）, isopropanol （IPA） and mixed additive were tentatively introduced for the texturization of HIT solar cells in this study. Then, a mixture including nitric acid （HNO3）, hydrofluoric acid （HF） and glacial acetic acid （CH3COOH） was employed to round pyramid structure. The morphology of textured surface and the influence of etching time on surface reflectance were studied, and the relationship between etching time and surface reflectance, vertex angle of pyramid structure was analyzed. It was found that the mixture consisting of 1.1 wt% NaOH, 3 vol% IPA and 0.3 vol% additives with etching time of 22.5 min is the best for H1T solar cells under the condition of 80℃. Uniform pyramid structure was observed and the base width of pyramid was about 2-4 μm. The average surface reflec- tance was 11.68%. Finally the effect of different processes on the performance of HIT solar cells was investigated. It was shown that these texturization and rounding techni- ques used in this study can increase short circuit current （Jsc）, but they have little influence on fill factor （FF） and open circuit voltage （Voo） of HIT solar cells.

关键词： texturization reflectance pyramid hetero-junction with intrinsic thin-layer （HIT） solar cells

阿拉善高原东部4种飞播灌木种子萌发的适宜条件

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中国沙漠 2024年第1期44卷 96-101页

作者：朱雅娟赵晨光李慧瑛王阿晴中国林业科学研究院生态保护与修复研究所北京100091 阿拉善盟林业与草原研究所内蒙古阿拉善左旗750306

阿拉善高原地处内蒙古西部,沙漠和戈壁广泛分布,是中国北方主要沙尘源地。飞播是当地治理土地荒漠化的重要途径。通常,飞播之后植物的萌发主要受气象和生境等自然因素影响。沙冬青(Ammopiptanthus mongolicus)、花棒(Corethrodendron fr... 详细信息

阿拉善高原地处内蒙古西部,沙漠和戈壁广泛分布,是中国北方主要沙尘源地。飞播是当地治理土地荒漠化的重要途径。通常,飞播之后植物的萌发主要受气象和生境等自然因素影响。沙冬青(Ammopiptanthus mongolicus)、花棒(Corethrodendron fruticosum)、柠条锦鸡儿(Caragana korshinskii)和蒙古扁桃(Prunus mongolica)是阿拉善高原荒漠的4种优势灌木。通过温室盆栽实验,研究降雨量、播种深度和土壤类型对4种灌木种子萌发的影响,优化飞播技术,为精准治沙提供理论依据。模拟的3个降雨量分别是首次浇水10、15、20 mm,之后每2天浇水5 mm,共10次。4个播种深度分别是0.5、1、2、3 cm。4种土壤类型分别是微细沙、细沙、中沙和粗沙。结果表明:沙冬青种子萌发的适宜条件是首次浇水15~20 mm,其他3种灌木则为首次浇水10~20 mm。沙冬青种子的适宜播种深度是0.5~1 cm,其他3种灌木则是0.5~2 cm;3 cm只有少量花棒萌发。沙冬青在微细沙、细沙和中沙里的萌发率较高,而在粗沙中的萌发率较低;其他3种灌木在4种土壤中的萌发率都较高。因此,在阿拉善高原东部,沙冬青适宜15 mm以上降雨后在流动、半流动和半固定沙丘飞播,不适宜戈壁飞播;其他3种灌木则适宜10 mm以上降雨后在流动、半流动、半固定沙丘和戈壁飞播。

关键词：飞播降雨量播种深度土壤类型

2,3-Seco and 3-nor guaianolides from Achillea alpina with antidiabetic activity

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中国天然药物:英文版 2023年第8期21卷 610-618页

作者： XUE Guimin zhao chenguang XUE Jinfeng DUAN Jiangjing PAN Hao zhao Xuan YANG Zhikang CHEN Hui SUN Yanjun FENG Weisheng College of Pharmacy Henan University of Chinese MedicineZhengzhou 450046China

In this study,we presented the isolation and characterization of eight novel seco-guaianolide sesquiterpenoids(1-8)and two known guaianolide derivatives(9 and 10),from the aerial part of Achillea alpina L..Compounds 1-3 were identified as guaianolides bearing an oxygen insertion at the 2,3 position,while compounds 4-8 belonged to a group of special 3-nor guaianolide sesquiterpenoids.The structural elucidation of 1-8,including their absolute configurations,were accomplished by a combination of spectroscopic data analysis and quantum electronic circular dichroism(ECD)calculations.To evaluate the potential antidiabetic activity of compounds 1-10,we investigated their effects on glucose consumption in palmitic acid(PA)-mediated HepG2-insulin resistance(IR)cells.Among the tested compounds,compound 7 demonstrated the most pronounced ability to reverse IR.Moreover,a mechanistic investigation revealed that compound 7 exerted its antidiabetic effect by reducing the production of the pro-inflammatory cytokine IL-1β,which was achieved through the suppression of the NLRP3 pathway.

关键词： Achillea alpina Seco-guaianolide Glucose consumption Antidiabetic activity

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某型号巡飞弹发射架出架过程研究

现代制造技术与装备 2024年第5期60卷 52-54页

作者：赵晨光周锦程刘贝龚敏浩刘勇男上海航天设备制造总厂有限公司上海200245

火箭助推起飞是巡飞弹常用的一种发射方式。这种方式可以利用发射架使巡飞弹在极短的时间内实现从静止状态到飞行状态的转换,属于零长起飞方式。巡飞弹从发射架上发射升空,无须提供跑道,场地适应性好,起飞过程快捷隐蔽,特别适用于陆军... 详细信息

火箭助推起飞是巡飞弹常用的一种发射方式。这种方式可以利用发射架使巡飞弹在极短的时间内实现从静止状态到飞行状态的转换,属于零长起飞方式。巡飞弹从发射架上发射升空,无须提供跑道,场地适应性好,起飞过程快捷隐蔽,特别适用于陆军部队机动作战。为研究影响地面发射式巡飞弹发射弹体姿态(偏航、俯仰、滚转角变化)的主要因素,利用三维设计软件Pro/E设计发射架的三维模型,使用动力学仿真软件机械系统动力学自动分析(Automatic Dynamic Analysis of Mechanical Systems,ADAMS),对出架过程进行动力学仿真分析,并开展试验测试弹体在架的蓄力和出架情况,验证发射架设计的合理性,给出弹体预调纠偏控制的合理建议。

关键词：巡飞弹地面发射发射架出架过程动力学仿真