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Modeling Method for Assembly Variation Propagation Taking Account of Form Error

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Chinese Journal of Mechanical Engineering 2013年第4期26卷 641-650页

作者： zuo Fuchang JIN xin ZHANG Zhijing ZHANG Tingyu School of Mechanical Engineering Beijing Institute of Technology

The propagation of variations, such as fixture errors and datum errors resulting from assembly and machining processes, has been extensively studied. However, only a few studies that focus on form error propagation in assembly systems have been implemented. Machining errors, especially form errors, have great impact on assembly accuracy and accuracy stability of precision mechanical systems. With form errors being the research object, a method for calculating mating variation and specifying mating coordinate is proposed to improve the accuracy of the variation propagation model. Taking into account the form error of mating surfaces, the assembly variation propagation of a precision mechanical system is analyzed, and the brief derivation procedure of the variation propagation model is introduced afterwards. The variation propagation model involves a new concept of mating variation specified by the two mating surfaces. An innovative method, the difference surface search based method, is proposed to calculate the mating variation amongst the mating surfaces. The obtained mating variation is then utilized to specify the mating coordinate in the variation propagation model. Moreover, FEM is employed to simulate the contact state of the two mating surfaces to demonstrate effectiveness of the proposed method. Meanwhile, the mating variation and mating coordinate obtained are incorporated into the assembly variation propagation model, which is then verified by a following case study through a comparison between the calculated results and the experimental results. The comparing results indicate that the established model improves the prediction of assembly accuracy. The developed model enables the investigation of various fundamental issues in variation reduction, including variation analysis, process monitoring, accuracy prediction, and accuracy control.

关键词： variation propagation precision mechanical system form error difference surface contact point

A new isolation device using shape memory alloy and its application for long-span structures

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Earthquake Engineering and Engineering Vibration 2011年第2期10卷 239-252页

作者： Ding Youliang Chen xin Li Aiqun zuo Xiaobao Key Laboratory of Concrete and Prestressed Concrete Structure of Ministry of Education Southeast University Nanjing 210096 China Department of Civil Engineering Nanjing University of Science ＆ Technology Nanjing 210094 China

The key points to consider in determining the effectiveness of using structural isolation with shape memory alloys （SMA） are the constitutive model, the SMA isolation device and the analysis method. In this paper, a simplified constitutive model based on the classic theory of plasticity is proposed to simulate the behavior of the superelasticity of the SMA, in which the martensite volume fraction is considered as one of the state variables. Comparisons between simulation results and experimental results are made and indicate that the proposed constitutive model yields stress-strain curves that are in good agreement with the experimental ones. Thus, the proposed model can correctly simulate the yield mechanism and energy dissipation capacity of the SMA. Next, in order to make full use of the superelasticity of SMA, a new SMA isolator composed of pre-tensioned SMA bars is presented. Then, a finite element analytical model is established to simulate the behavior of the SMA isolator according to its configuration and simplified constitutive model. Finally, a simplified design method for long-span structures installed with SMA isolators is proposed, which is further used to investigate the isolation effects of a space grid structure. Results show that the SMA isolator can reduce the seismic responses of the structure effectively, which indicates the effectiveness of the proposed SMA isolation method.

关键词： shape memory alloy super-elasticity constitutive model seismic response structural isolation space gridstructure

有机肥替代部分化肥氮对糯玉米产量、品质及氮素利用的影响

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作物学报 2024年第4期50卷 1053-1064页

作者：娄菲左怿平李萌代鑫萌王健韩金玲吴舒李向岭段会军河北科技师范学院农学与生物科技学院/河北省作物逆境生物学重点实验室河北秦皇岛066004 河北农业大学农学院/华北作物改良与调控国家重点实验室河北保定071001 河北环境工程学院/河北省农业生态安全重点实验室河北秦皇岛066102

研究有机肥替代部分化肥氮对糯玉米产量、品质及氮素利用的影响,探索糯玉米生产中有机肥与化肥的最佳配施比例,为河北省鲜食糯玉米优质栽培提供理论依据。2021和2022年设置田间试验,以糯玉米品种斯达糯41为试验材料,采用随机区组设计,... 详细信息

研究有机肥替代部分化肥氮对糯玉米产量、品质及氮素利用的影响,探索糯玉米生产中有机肥与化肥的最佳配施比例,为河北省鲜食糯玉米优质栽培提供理论依据。2021和2022年设置田间试验,以糯玉米品种斯达糯41为试验材料,采用随机区组设计,设置不施氮(T1)、常量化肥氮(T2)、有机肥替代20%化肥氮(T3)、有机肥替代40%化肥氮(T4)、有机肥替代60%化肥氮(T5)和有机肥替代100%化肥氮(T6)共6个处理。结果表明,与T2处理相比,T3、T4和T5处理提高了糯玉米鲜果穗产量,分别增加3.08%、13.61%、3.20%;T3~T6处理下氮素利用效率降低,T3、T4和T5处理氮肥偏生产力和氮肥农学效率增加。与T2处理相比,T3~T5处理提高了糯玉米外观和品尝品质评分,其中T4处理总评分最高,这主要是因为有机肥替代部分化肥氮增加了籽粒总淀粉和支链淀粉含量,降低了籽粒蛋白质和可溶性糖含量,同时改善了籽粒质构特性,籽粒硬度、弹性和咀嚼性增加,内聚性降低。综上所述,在总施氮量为180 kg hm^(–2)条件下,有机肥替代部分化肥氮的比例为总施氮量40%时可以实现糯玉米鲜果穗产量和品质的协同提高。

关键词：糯玉米有机肥产量氮效率籽粒品质

In-situ Fluid Phase Variation along the Thermal Maturation Gradient in Shale Petroleum Systems and Its Impact on Well Production Performance

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Journal of Earth Science 2023年第4期34卷 985-1001页

作者： Qianyou wang Wei Yang Yaohua Li Zhenxue Jiang Ming Wen Rusi zuo xin wang Zixin Xue Yaohua wang State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing 102249China Department of Earth Ocean and Ecological SciencesUniversity of LiverpoolLiverpool L693GPUK Unconventional Oil and Gas Sciences and Technology Institute China University of PetroleumBeijing 102249China Oil and Gas Survey China Geological SurveyBeijing 100083China Now at the Lyell Centre Heriot-Watt UniversityEdinburgh EH144APUK State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China College of Geosciences China University of PetroleumBeijing 102249China Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Central South UniversityChangsha 410083China

In-situ fluid phase behavior is important in determining hydrocarbon contents and the multiphase flow through shale *** gas-to-oil ratio(GOR) has been recognized as a critical indicator of fluid ***,little is known about the impact of fluid phase variation across the thermal maturity on shale oil/gas production(e.g.,estimated ultimate recovery,EUR).According to the specific gravity ratio of oil/gas,the producing GOR was converted and normalized into a mass fraction of gas in total hydrocarbons(MGOR) to compare North American shale oil/gas plays with Chinese shale oil and hybrid gas-condensate plays.A correlation between MGOR,the fluid phases,and production data was established to identify five phase stages of *** systematically with the different production zones,which shows promise in rapidly indicating the well production performance and high production stages of shale oil/gas *** hybrid shale gas condensate index,Tmax,and total gas contents were integrated to present the fluid types and maturity of shale gas-condensates,which indicates fluid phase and production variation across thermal *** results offer a unique perspective on the shale oil reservoir producibility based on the impact of GOR on fluid phases and EUR from the dominant global oil/gas plays.

关键词： shale oil shale gas gas condensate fluid phase thermal maturity sweet spots GOR EUR.

动态高温反偏应力下的SiC MOSFET测试平台及其退化机理研究

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电源学报 2024年第3期22卷 211-219页

作者：左璐巍辛振蒙慧周泽余彬罗皓泽河北工业大学省部共建电工装备可靠性与智能化国家重点实验室天津300401 浙江大学电气工程学院杭州310058 南京信息工程大学自动化学院南京210044 中国电源学会

为研究SiC MOSFET在动态漏源应力下的退化机理,开发了一种具有dVds/dt可调功能、最高可达80 V/ns的动态反向偏置测试平台。针对商用SiC MOSFET进行动态高温反偏实验,讨论高电压变化率的动态漏源应力对SiC MOSFET电学特性的影响。实验结... 详细信息

为研究SiC MOSFET在动态漏源应力下的退化机理,开发了一种具有dVds/dt可调功能、最高可达80 V/ns的动态反向偏置测试平台。针对商用SiC MOSFET进行动态高温反偏实验,讨论高电压变化率的动态漏源应力对SiC MOSFET电学特性的影响。实验结果显示,器件的阈值电压和体二极管正向导通电压增加,说明器件JFET区上方的栅氧层和体二极管可能发生了退化。通过Sentaurus TCAD分析了在高漏源电压及高电压变化率下平面栅型SiC MOSFET的薄弱位置,在栅氧层交界处和体二极管区域设置了空穴陷阱,模拟动态高温反偏对SiC MOSFET动静态参数的影响。

关键词：动态高温反偏测试退化机理 SiC MOSFET 可调dV_(ds)/dt

河套平原沙漠区3种乡土树种人工栽培后的生态适应性

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植物研究 2024年第4期44卷 612-624页

作者：孙耀文马迎梅任晓敏韩峰陈鑫左朗内蒙古农业大学沙漠治理学院呼和浩特010010 内蒙古农业大学草原与资源环境学院呼和浩特010010

乌兰布和沙漠东北段的防护林是保护东部河套平原农业生产的重要生态屏障,由于对人工造林研究缺乏重视,许多防护林体系中的林分有一定的衰退趋势。研究乡土树种人工栽培后的生态适应性,是指导人工防护林建设和可持续经营的重要举措。为... 详细信息

乌兰布和沙漠东北段的防护林是保护东部河套平原农业生产的重要生态屏障,由于对人工造林研究缺乏重视,许多防护林体系中的林分有一定的衰退趋势。研究乡土树种人工栽培后的生态适应性,是指导人工防护林建设和可持续经营的重要举措。为了深入探究乌兰布和沙漠乡土树种人工栽培后的生态适应性,本文以3种乡土树种沙冬青(Ammopiptathus mongolicus)、霸王(Zygophyllum xanthoxylon)和蒙古扁桃(Prunus mongolica)为研究对象,通过测定功能性叶片表皮形态、解剖结构、生理指标,结合当地气象数据,阐释3种植物对沙漠环境的适应机制。结果表明:3种植物分别以不同方式适应沙漠环境。沙冬青通过增大叶面积来增加受光面积、提高光合效率,利用密集的表皮毛和发达的角质层强化叶片机械防御能力,降低强光灼伤及水分蒸腾,维持细胞水分平衡,从而降低细胞膜脂过氧化。蒙古扁桃叶片簇生,通过增加叶片数量增加受光面积、提高光合效率,通过卷曲叶片躲避强光灼伤,通过特化气孔位置(将气孔全部分布于叶片下表面),利用发达的维管束、丰富的黏液细胞和晶体结构来降低水分蒸腾,维持细胞水分平衡,从而降低细胞膜脂过氧化。霸王叶片呈圆柱状条形结构,通过降低风阻,降低叶片遭受风沙流危害的概率,通过生理代谢调节提高叶片抗氧化物酶活性和渗透调节物质含量,维持细胞水分和活性氧代谢平衡。这些发现揭示了3种植物在应对荒漠环境时所采取的不同的适应策略,为乌兰布和沙漠东北部乡土树种的引种驯化提供了新思路。

关键词：沙漠生态系统生态适应能力解剖结构生理特性防护林

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Distributional expansion of maximum from logarithmic general error distribution

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Applied Mathematics(A Journal of Chinese Universities) 2016年第2期31卷 157-164页

作者： YANG Geng LIAO xin PENG zuo-xiang School of Mathematics and Statistics Southwest University Business School University of Shanghai for Science and Technology

Logarithmic general error distribution is an extension of lognormal distribution. In this paper, with optimal norming constants the higher-order expansion of distribution of partial maximum of logarithmic general erro... 详细信息

关键词： Extreme value distribution Higher-order expansion Logarithmic general error distribution,Maximum

Minor change in the length of carbon chain has a great influence on the antitumor effect of paclitaxel-fatty alcohol prodrug nanoassemblies:Small roles,big impacts

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Nano Research 2022年第4期15卷 3367-3375页

作者： xin wang Lingxiao Li Danping wang Shiyi zuo Tian Liu Fudan Dong Xuanbo Zhang Zhonggui He Bingjun Sun Jin Sun Wuya College of Innovation Shenyang Pharmaceutical UniversityShenyang 110016China Department of Radiology Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical SchoolNanjing 210008China School of Pharmacy Shenyang Pharmaceutical UniversityShenyang 110016China

Prodrug-based nanoassembly emerges as a hopeful way for the efficient delivery of antitumor drugs,with carrier-free structure and ultra-high drug *** chains are widely used to design self-assembling *** impacts of the length of carbon chains on the self-assembly stability,drug delivery efficiency and antitumor effect of prodrugs have not been fully ***,three paclitaxel prodrugs were synthesized by conjugating paclitaxel with octanol(C_(8)),decanol(C_(10))or dodecanol(C_(12))through disulfide *** three prodrugs could form homogeneous nanoparticles,with over 50%drug loading and redox ***,the length extension of carbon chains ameliorates the self-assembly and the colloidal stability of prodrugs,thus improving the drug delivery *** optimal paclitaxel-dodecanol prodrug nanoassemblies exhibit better antitumor efficacy than Taxol and *** findings are meaningful for the rational design of advanced nanomedicines in cancer therapy.

关键词： prodrug self-assembly chain length paclitaxel redox responsive drug release

沙库巴曲缬沙坦联合依折麦布、美托洛尔治疗老年冠心病的效果及对心肌损伤标志物、TGF-β_(1)、ICAM-1水平的影响

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临床医学研究与实践 2024年第11期9卷 37-40页

作者：辛浩代雪茹左梅延安大学咸阳医院陕西咸阳712000

目的探讨沙库巴曲缬沙坦联合依折麦布、美托洛尔治疗老年冠心病(CHD)的效果及对心肌损伤标志物、转化生长因子-β_(1)(TGF-β_(1))、细胞间黏附分子-1(ICAM-1)水平的影响。方法选取2020年3月至2022年1月我院收治的120例老年CHD患者为研... 详细信息

目的探讨沙库巴曲缬沙坦联合依折麦布、美托洛尔治疗老年冠心病(CHD)的效果及对心肌损伤标志物、转化生长因子-β_(1)(TGF-β_(1))、细胞间黏附分子-1(ICAM-1)水平的影响。方法选取2020年3月至2022年1月我院收治的120例老年CHD患者为研究对象,以随机数字表法将其分为对照组与观察组,各60例。对照组给予依折麦布、美托洛尔治疗,观察组在对照组基础上加沙库巴曲缬沙坦治疗。比较两组的治疗效果。结果观察组的治疗总有效率高于对照组(P0.05);治疗后,观察组的NT-proBNP、cTnI及CK-MB水平低于对照组(P0.05);治疗后,观察组的TGF-β_(1)水平高于对照组,ICAM-1水平低于对照组(P<0.05)。结论沙库巴曲缬沙坦联合依折麦布、美托洛尔治疗老年CHD不仅能够提高治疗效果,降低心肌损伤标志物水平,还能调节TGF-β_(1)、ICAM-1表达,值得推广。

关键词：沙库巴曲缬沙坦依折麦布美托洛尔老年冠心病心肌损伤标志物