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Analysis and Key Parameter Optimization Design of Leningrader Seal Performance

Wuhan University Journal of Natural Sciences 2024年第2期29卷 177-192页

作者： YANG Dongya WANG Xuelin WANG Feng ZHANG hailong GAO gui College of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050Gansu China Wenzhou Pump and Valve Engineering Research Institute Lanzhou University of TechnologyWenzhou 325000ZhejiangChina State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000GansuChina

In order to improve the performance and service life of the Leningrader seal of the Stirling engine piston rod,interference,pre-load and friction coefficient were taken as influencing factors,and the curved surface response method was adopted to reduce the contact stress of sealing surface and von Mises stress of the sealing sleeve as the response index,with the optimization goal of reducing wear and extending life.The above three key parameters are analyzed and optimized,the influence of each parameter on the sealing performance and service life is obtained,and the best combination scheme of the three is determined.The results show that the interaction between pre-tightening force and interference fit has the greatest impact on contact stress.The interaction between interference fit and friction coeffi-cient has the most significant effect on von Mises stress.The optimized parameters can reduce the maximum contact stress and maximum von Mises stress of the sealing sleeve by 26.3%and 20.6%,respectively,under a media pressure of 5-9 MPa.Test bench verification shows that the leakage of the optimized sealing device in 12 h is reduced by 0.44 cc·min^(-1)(1 cc=1 cm^(3)).The wear rate of the sealing sleeve is 1.08%before optimization and 0.45%after optimization,indicating that the optimized parameters in this paper are effective.

关键词： Leningrader seal Stirling engine performance analysis optimized design parameter configuration

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Pterostilbene antagonizes homocysteine-induced oxidative stress,apoptosis and lipid deposition in vascular endothelial cells

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Food Science and Human Wellness 2023年第5期12卷 1683-1692页

作者： Qiao Jiang Li Wang Xu Si Yuanyuan Bian Weijia Zhang Huijun Cui hailong gui Ye Zhang Bin Li Dehong Tan College of Food Science Shenyang Agricultural UniversityShenyang 110866China State Key Laboratory of Food Science and Technology Jiangnan UniversityWuxi 214122China

Hyperhomocysteinemia(HHcy)causes oxidative stress, induces apoptosis, and leads to damage to the vascular endothelium is the starting point of atherosclerosis. Pterostilbene(Pte)has been reported to have antioxidant and anti-apoptotic effects under various pathological conditions. The purpose of this study was to explore whether Pte can inhibit the oxidative stress and apoptosis of vascular endothelium induced by homocysteine(Hcy)and to explain the possible mechanism by which it occurs. The results showed that 20 μmol/L Pte significantly reduced the accumulation of reactive oxygen species, malondialdehyde, and lipids in cells induced by Hcy and promoted the activities of superoxide dismutase and catalase. The Hoechst 33342/PI staining assay showed that Pte antagonized Hcy-induced apoptosis. Pte inhibited Hcy-induced Akt dephosphorylation, increased p53, and decreased the Bcl-2/Bax ratio and caspase-9/caspase-3 activation in a dose-dependent manner. LY294002 pretreatment partially reversed the protective effect of Pte by blocking the PI3K/Akt pathway. Moreover, Pte reduced lipid deposition in human umbilical vein endothelial cells(HUVECs). This study proposes that Pte can inhibit Hcy-induced oxidative stress and apoptosis of HUVECs, and the PI3K/Akt/p53 signaling pathway of apoptosis was revealed. These results suggest that Pte exhibits significant potential for dealing with HHcy-induced vascular endothelial injury, such as atherosclerosis.

关键词： Pterostilbene Hyperhomocysteinemia Methionine Polyphenols Atherosclerosis

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东北地区大豆扩种政策市场效果与风险防范研究

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经济纵横 2024年第4期 99-107页

作者：蔡海龙桂松中国农业大学经济管理学院北京100083

近年来,我国实施了新一轮大豆扩种政策。在一系列“超常规”措施推动下,2022年大豆产量大幅增加。但通过对东北地区的调研发现,大豆价格高开低走,豆农收益低于预期,在国储和省储的助力下,产销衔接基本平稳;但本地大豆加工企业开工率低,... 详细信息

近年来,我国实施了新一轮大豆扩种政策。在一系列“超常规”措施推动下,2022年大豆产量大幅增加。但通过对东北地区的调研发现,大豆价格高开低走,豆农收益低于预期,在国储和省储的助力下,产销衔接基本平稳;但本地大豆加工企业开工率低,农户种植大豆的积极性不高。在大豆和玉米“双短缺”的背景下,进一步扩种大豆的风险和挑战加剧,需要引起高度重视。为此,扩种大豆政策不能仅在种植环节发力,更需要在整个产业链上协同推进,构建长效政策机制。在稳存量、增储备、促加工的发展思路基础上,应通过扩种速度缓一些、收储规模增一些、加工转化多一些来化解相应风险。

关键词：大豆扩种生产者补贴饲料粮安全东北地区

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斯特林机帽式密封性能分析及回归参数优化设计

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工程科学与技术 2024年第3期56卷 287-300页

作者：杨东亚张海龙王学霖王锋高贵兰州理工大学机电工程学院甘肃兰州730050 兰州理工大学温州泵阀工程研究院浙江温州325000 中国科学院兰州化学物理研究所固体润滑国家重点实验室甘肃兰州730000

为改善斯特林机活塞杆帽式密封性能,首先采用数值仿真分析了5 MPa工质压力下其静、动态力学特性,从而获取了O型圈内径尺寸L_(N)、C型环径向壁厚T和装配过盈量S这3个关键结构参数对密封性能的影响规律。在此基础上,利用回归设计法以配伍... 详细信息

为改善斯特林机活塞杆帽式密封性能,首先采用数值仿真分析了5 MPa工质压力下其静、动态力学特性,从而获取了O型圈内径尺寸L_(N)、C型环径向壁厚T和装配过盈量S这3个关键结构参数对密封性能的影响规律。在此基础上,利用回归设计法以配伍面最大接触压力平稳且密封可靠为优化目标,对密封结构的上述3个关键参数进行优化设计以确定其最佳匹配方案,最后通过密封试验台验证了本文优化设计方法的准确性和普适性。结果表明:活塞杆与C型环密封面中间区域上最大接触压力随L_(N)和S的增大而增大,但随T的增大而减小;通过估计回归系数和方差分析(ANOVA)发现,L_(N)对密封性能影响最为显著、S次之、T影响最小;L_(N)和T、L_(N)和S交互项对响应显著,而T和S交互项对响应不显著;当L_(N)为13.745 mm、T为0.40 mm和S为0.020 mm时,优化密封件对应的正行程最大接触压力为9.01 MPa、回程为9.75 MPa,较工程在用密封件(L_(N)=13.780 mm、T=0.50 mm、S=0 mm)最大接触压力分别降低了14.7%和25.5%。实验进一步验证了优化密封件的密封性能和使用寿命均优于工程在用密封件,并且在不同工质压力下优化密封件的接触压力均匀性更好,减摩延寿效果显著,充分证明本文性能分析与优化设计方法准确有效。

关键词：斯特林机帽式密封性能分析参数优化回归设计

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串珠状溶洞数量影响灌注桩顶部水平受拉特性试验研究

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湖南大学学报（自然科学版） 2024年第1期51卷 67-78页

作者：周德泉海军刘宏利高祁刘海龙桂海麒孙卫勇谢瑞庭朱沁周毅长沙理工大学土木工程学院湖南长沙410076 中交四航局第六工程有限公司广东珠海519000 中国路桥工程有限责任公司北京100011

采用室内模型试验,对比研究串珠状溶洞数量对灌注桩顶部水平受拉特性的影响,为岩溶强发育区嵌岩桩的水平承载力设计提供试验依据.结果表明:1)桩顶水平荷载相同时,上部土层段桩身水平位移、桩身弯矩(峰值)、桩侧土抗力随溶洞数量的增多... 详细信息

采用室内模型试验,对比研究串珠状溶洞数量对灌注桩顶部水平受拉特性的影响,为岩溶强发育区嵌岩桩的水平承载力设计提供试验依据.结果表明:1)桩顶水平荷载相同时,上部土层段桩身水平位移、桩身弯矩(峰值)、桩侧土抗力随溶洞数量的增多而增大,单桩水平承载力随溶洞数量增多而明显减弱.2)上部土层段桩身水平位移随桩顶水平荷载增大而增大,桩顶水平位移最大,嵌岩段很小甚至为0;弯矩M-深度z曲线整体呈抛物线形,桩身弯矩在土岩界面和上层溶洞与底板界面呈现2个峰值,弯矩的变化仅仅影响到上层溶洞及其底板,第2层溶洞及其以下的弯矩几乎为0,土岩界面弯矩最大、截面最危险;土抗力p-深度z曲线呈“凸肚”形.3)溶洞数量增加,位置越高,p-y曲线越容易收敛,可以采用p/pub=α(y/y50)β拟合土层段的桩身p-y曲线.溶洞数量对α与β值变化幅度的影响较小,α与β值变化幅度体现p-y曲线随深度变化的敏感度,两者敏感度随溶洞数量增多而增大.4)工程桩刺穿串珠状溶洞时,为了提高单桩水平抗拉能力,建议采用注浆法改善上部岩土性质,加大土岩界面处桩身配筋率,并将桩身嵌入上层溶洞底板一定深度,防止基桩在土岩界面处发生弯曲破坏.

关键词：桩基工程岩溶水平受荷 p-y曲线模型试验

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湖南水口山矿田金矿控矿因素、成矿演化及成矿预测

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矿产与地质 2024年第2期38卷 207-218页

作者：陈平波桂祁零陈海龙莫平衡湖南省遥感地质调查监测所湖南长沙410015

水口山矿田是一大型金多金属矿田,其金资源储量达90 t。通过系统总结各金矿床地质特征,初步厘定金矿化期次,进而分析控矿因素,对成矿演化进行探讨,建立成矿模型,进行成矿预测。研究表明,区内金矿化与地层、倒转褶皱、断裂、花岗岩体关... 详细信息

水口山矿田是一大型金多金属矿田,其金资源储量达90 t。通过系统总结各金矿床地质特征,初步厘定金矿化期次,进而分析控矿因素,对成矿演化进行探讨,建立成矿模型,进行成矿预测。研究表明,区内金矿化与地层、倒转褶皱、断裂、花岗岩体关系密切。其中地层控矿主要表现为成矿层位赋存于当冲组、栖霞组层间破碎带或与岩体接触带中;构造控矿主要表现为背斜虚脱空间、层间破碎带、断裂带等是矿化富集的有利部位;岩浆岩控矿表现除岩体接触带控矿外,还有不同成因类型金矿围绕岩体呈分带现象,围绕岩体由地表到深部表现为氧化淋滤型独立型金矿—接触破碎独立型金矿—浅成低温热液独立型金矿—远距离热液充填交代伴生型金矿—接触交代伴生型金矿。金矿石沉淀与来自岩浆热液的成矿流体及大气降水引发的水岩反应、混合作用、沸腾作用有关,是成矿的主要3种机制。

关键词：金矿控矿因素矿化期次成矿演化找矿预测水口山湖南

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Kuroshio Intrusion Combined with Coastal Currents Affects Phytoplankton in the Northern South China Sea Revealed by Lipid Biomarkers

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Journal of Ocean University of China 2023年第2期22卷 576-586页

作者： WANG Yaoyao BI Rong GAO Jiawei ZHANG hailong LI Li DING Yang JIN gui’e ZHAO Meixun Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Chemistry Theory and TechnologyMinistry of EducationOcean University of ChinaQingdao 266100China Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China

The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here,we investigated the concentrations of phytoplankton biomarkers and their proportions in surface suspended particles from 47 sites of the NSCS during summer of 2017 and 2019.Brassicasterol/epi-brassicasterol,dinosterol,and C37 alkenones were used as proxies of biomass for diatoms,dinoflagellates,and haptophytes,respectively,and their sum indicating total phytoplankton biomass.A three end-member mixing model was applied to quantitatively assess the influence extent of the Kuroshio intrusion and the coastal currents.Our results showed that the Kuroshio intrusion and the coastal currents contributed equally to the overall surface water masses in the study area;however,the two currents had distinct effects on the spatial distribution of phytoplankton.For phytoplankton biomass,the eutrophic coastal currents were likely to be the main controlling factors,while the impact of the Kuroshio intrusion was weak and stimulated significant increases in phytoplankton biomass only at certain boundary sites.For phytoplankton community structures,the Kuroshio and its intrusion were the main factors,resulting in an increase in the proportions of dinoflagellates and haptophytes.The proportion of diatoms slightly increased due to the influence of the coastal currents.Our study quantifies the effects of the Kuroshio and the coastal currents on phytoplankton in the NSCS in terms of hydrological parameters,providing an important basis for the understanding of ecological functions and biogeochemical cycles in marginal sea-open ocean boundary regions.

关键词： sterols alkenones phytoplankton northern South China Sea Kuroshio coastal currents

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A preliminary exploration of the mechanism for the occurrence of two types of various magnetic structures in the magnetotail

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Chinese Science Bulletin 2001年第12期46卷 981-986页

作者： JIN Shuping HU Xianpeng gui hailong LIU Zhenxing PU Zuyin B.Wilken Department of Earth and Space Science University of Science and Technology of ChinaHefei 230026China Center for Space Sciences and Application Research Chinese Academy of SciencesBeijing 100080China Department of Geophysics Peking UniversityBeijing 100871China Max-Planck Institut fuer Aeronomie D-37191 Katlanburg-LindauGermany

As well known, the magnetic cross-tail component By in the magnetotail is in direct proportion to the in-terplanetary magnetic field (IMF) By component. And the polarity of IMF and plasmoid / flux rope By components do indeed agree. This results indicate that the IMF By penetrates plasmoids and the magnetic structures must therefore be three-dimensional. In this note, the dynamical processes of magnetotail in the course of a substorm are studied using a MHD code with two-dimensions and three components on the basis of two types of initial equilibrium solutions of the quiet magnetotail. The numerical results of two cases illustrate various features of time evolution of By component that correspond to two kinds of plasmoid-like structures: one is associated with a flux rope core and the other resembles a 'closed loop' plamoid. Therefore, the occurrence of various magnetic structures in the magnetotail might be related to nonsteady driven reconnection with different distributions of the By component.

关键词： magnetospheric substorm magnetic cross-tail component By plasmoid-like structures nonsteady magnetic reconnection.

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Phytolith carbon sequestration in bamboos of different ecotypes:a case study in China

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Chinese Science Bulletin 2014年第31期59卷 4816-4822页

作者： Beilei Li Zhaoliang Song hailong Wang Fengshan Guo Renyi gui Xiaomin Yang Ruisheng Song School of Environmental and Resource Sciences Zhejiang Agricultural and Forestry University Zhejiang Provincial Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration Zhejiang Agricultural and Forestry University State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences School of Forestry and Bio-technology Zhejiang Agricultural and Forestry University

Occlusion of carbon(C) within phytoliths(Phyt OC) is becoming one of the most promising terrestrial C sequestration mechanisms. This study explored the production of Phyt OC within 35 bamboo species belonging to three ecotypes using methods of microwave digestion. The aim of this study is to explore the present and potential C sequestration rate within phytoliths of bamboo species from three ecotypes. Phyt OC content in bamboos of three ecotypes ranges from 0.07 % to 0.42 %. The mean Phyt OC production flux decreases as: clustered bamboo(0.050 ±0.016 t CO2ha-1a-1) & mixed bamboo(0.049 ± 0.016 t CO2ha-1a-1) [ scattered bamboo(0.038 ± 0.020 t CO2ha-1a-1). The phytolith carbon sequestration in Chinese bamboo is estimated to be 0.293 ± 0.127 Tg(1 Tg =1012g) CO2a-1; approximately 75 %, 3 %, and 22 % of which is contributed from scattered, mixed and clustered bamboo, respectively. Taking the Phyt OC production flux of 0.18 ± 0.12 t CO2ha-1a-1and current annual area increasing rate of 3 %, global bamboo phytoliths wouldsequester 11.9 ± 7.9 Tg CO2a-1by 2050. Consequently,bamboo forests have significant potential to mitigate the increasing concentration of atmospheric CO2 by maximizing Phyt OC production flux and expanding bamboos.

关键词：植硅体生态型碳封存中国大气二氧化碳浓度案例 CO2 消解方法

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互联网农业信息获取与农户农机社会化服务采纳

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中国农业大学学报 2023年第9期28卷 234-246页

作者：桂松蔡海龙中国农业大学经济管理学院北京100083

针对农村互联网使用能否有效推动农户农业机械化发展这一现实问题,基于微观数据,采用OLS模型估计农户通过互联网获取农业信息对农机社会化服务采纳的影响,并使用工具变量法和处理效应模型控制内生性,同时进行多种稳健性检验和异质性分... 详细信息

针对农村互联网使用能否有效推动农户农业机械化发展这一现实问题,基于微观数据,采用OLS模型估计农户通过互联网获取农业信息对农机社会化服务采纳的影响,并使用工具变量法和处理效应模型控制内生性,同时进行多种稳健性检验和异质性分析。结果表明:1)通过互联网获取农业信息与农户农机社会化服务采纳为负相关关系,使用2种不同方法控制内生性得出的系数分别为-2.3和-1.8;2)异质性检验显示,互联网信息获取与农机社会化服务采纳的反向关系在老年农户和经营规模极小农户的样本中并不成立;3)机制检验显示,互联网信息获取对农户自购农机有显著的促进作用。使用互联网获取农业信息在现阶段抑制了农户农机社会化服务采纳,但有助于推动农户自购农机;在通过互联网获取信息到有效利用网络信息获取收益之间还有更深层次的数字鸿沟。

关键词：农机社会化服务互联网信息农业机械化农户采纳

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