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A Numerical Study Comparing the Effect on Residual Stresses of Two Different Types of Projectiles During Shot Peening

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Computers, Materials & Continua 2016年第3期51卷 203-215页

作者： j.Solórzano-López F.A.García-Pastor angélica Flores-Luna UNAM Facultad de QuímicaCiudad de MéxicoMéxico Cinvestav Unidad Saltillo CoahuilaMéxico TecNM Instituto Tecnológico de Tláhuac IIICiudad de MéxicoMéxico

Shot peening is a widely used technique to improve fatigue life in metallic *** processing technique introduces a subsurface compressive residual stress field through a plastic deformation of the surface caused by the impact of a large number of high-speed *** are a number of parameters that affect the residual stress field depth and *** effects of the impact angle,shot speed and shot geometry are currently being *** particular,substituting spherical cast shots by cylindrical cut wire shots is an attractive option,especially in terms of *** effect of shot geometry on residual stresses,however,needs to be further *** industrial-scale experimentation is costly and cumbersome,mathematical modeling offers a convenient alternative to carry out this type of *** present work shows a comparison between the residual stresses generated by the impact of spherical and cylindrical projectiles on a steel *** threedimensional model was developed using ABAQUS finite element commercial software(Release 6.12,Dassault Systémes,France).The results show that cylindrical shots generate residual stress fields t hat a re higher in magnitude than t hose generated by a spherical ***,the residual stress field of cylindrical shots impacting the surface at an oblique angle shows an important degree of *** effect is not found when spherical shots impact the surface at the same oblique angle.

关键词： Shot Peening Finite element method Residual Stresses

Attribution of explanatory factors for change in soil organic carbon density in the native grasslands of Inner Mongolia,China

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journal of Arid Land 2018年第3期10卷 375-387页

作者： jIN Dongyan Phil j MURRAY XIN Xiaoping QIN yifei CHEN Baorui QING Gele ZHang Zhao YAN Ruirui Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Department of Sustainable Soils and Grassland Systems Rothamsted Research North Wyke Department of Grassland Ecology and Animal Husbandry Xilingol Vocational College

The variation in soil organic carbon density（SOCD） has been widely documented at various spatial and temporal scales. However, an accurate method for examining the attribution of explanatory factors for change in SOCD is still lacking. This study aims to attribute and quantify the key climatic factors, anthropogenic activities, and soil properties associated with SOCD change in the native grasslands of Inner Mongolia, China, by comparing data between the 1960s and the 2010s. In 2007 and 2011, we resampled 142 soil profiles which were originally sampled during 1963–1964 in the native grasslands of Inner Mongolia. SOCD was determined in A horizon（eluvial horizon） of the soil. We selected the explanatory factors based on a random forest method, and explored the relationships between SOCD change and each of the explanatory factors using a linear mixed model. Our results indicated that the change in SOCD varied from the east to the west of Inner Mongolia, and SOCD was 18% lower in the 2010s than in the 1960s. The lower SOCD in the 2010s may primarily be attributed to the increasing in mean annual water surface evaporation, which explained approximately 10% and 50% of the total variation and explainable variation in the change in SOCD, respectively. The sand content of the soil is also a significant explanatory factor for the decrease in SOCD, which explained about 4% and 21% of the total variation and explainable variation in the change in SOCD, respectively. Furthermore, the collection of quantitative information on grazing frequency and duration may also help to improve our understanding of the anthropogenic factors that govern the change in SOCD.

关键词： soil organic carbon climate change soil texture mixed linear model effect isolation native grasslands

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美军航空卫生机动力量快速部署的启示

医学研究与战创伤救治 2024年第5期37卷 522-525页

作者：陈杨马亦飞刘振华周开园张建杰空军军医大学空军卫勤训练基地军事体育教研室西安710032 空军军医大学空军卫勤训练基地卫生勤务教研室西安710032

文章针对美军航空卫生机动力量建设的需求牵引与作用职能,通过研究分析美军航空卫生机动力量在人员架构、作用职能、训练培养等方面的先进做法,对中国人民解放军航空卫生机动力量建设提出启发建议,为实现联合作战条件下的保障打赢提供... 详细信息

文章针对美军航空卫生机动力量建设的需求牵引与作用职能,通过研究分析美军航空卫生机动力量在人员架构、作用职能、训练培养等方面的先进做法,对中国人民解放军航空卫生机动力量建设提出启发建议,为实现联合作战条件下的保障打赢提供理论参考。

关键词：航空医学机动力量快速部署

Phenotypic nutrient up-take differences in an alley cropping system in semi-arid Machakos, Kenya

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journal of Environmental Sciences 2001年第2期13卷 164-169页

作者： D.N. Mungai C.L.Coulson C.j. Stigter j.K. Ng’ang’a D.N.Mugendi Department of Geography University of NairobiNairdbiKenya Department of Botany University of NairobiNairobiKenya Department of Enviromnental Sciences Graduate School of Productian EcologyWageningen UniversityDuivendaal 26701 APThe Netherlands Department of Meteorology University of NairobiNairobiKenya Kenya Forestry Research Instiute(KEFRI NairobiKanya)

Alley cropping of Cassia siamea and maize was studied in semi arid Kenya for soil fertility improvement. Katumani composite maize was planted except in the short rains of 1988 (SR88) when a hybrid variety was sown. Therefore the grain yield per row increased differently in the alley cropped maize (CM). Sole maize (SM) and CM yields were higher in SR88 than in the long rains of 1988 (LR88) by 62% and 38%, while yields from the same treatments in LR89 were only 21% and 45% of those in SR88 These differences in relative maize yields are attributed to differences between the two maize varieties in competition under nutrient stress conditions.

关键词： alley cropping Cassia siamea maize nutrients maize yield semi arid condition soil moisture Kenya

Effect of non-uniform efficiency on higher-order cumulants in heavy-ion collisions

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Chinese Physics C 2021年第12期45卷 62-79页

作者： Fan Si yifei Zhang Xiaofeng Luo State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Key Laboratory of Quark&Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan 430079China

We perform a systematic study on the effect of non-uniform track efficiency correction in higher-order cumulant analysis in heavy-ion *** analytical derivation,we find that the true values of cumulants can be successfully reproduced by the efficiency correction with an average of the realistic detector efficiency for particles with the same charges within each single phase *** theoretical conclusions are supported by a toy model simulation by tuning the non-uniformity of the efficiency employed in the track-by-track efficiency correction *** valid averaged efficiency is found to suppress the statistical uncertainties of the reproduced cumulants ***,usage of the averaged efficiency requires a careful study of phase space *** study is important for carrying out precision measurements of higher-order cumulants in heavy-ion collision experiments at present and in future.

关键词： heavy ion collisions QCD phase diagram higher-order cumulants net-proton fluctuation Beam Energy Scan at RHIC

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正面碰撞下后排孕妇乘员损伤防护研究

振动与冲击 2024年第18期43卷 248-257页

作者：王平唐友名张义宋兵华方轶飞张海洋毛安莉厦门理工学院机械与汽车工程学院福建厦门361024 浙江科技大学机械与能源工程学院杭州310023 浙江大学医学院附属第四医院浙江义乌322000 吉利汽车研究院浙江省汽车安全技术重点实验室浙江宁波315336

为探讨孕妇乘员运输安全下的损伤风险,论文对比研究了常规安全带(三点式)和孕妇专用安全带(组合式)约束系统的防护效果。首先,建立并验证了正面全宽碰撞下后排女性乘员约束系统模型;其次,建立妊娠30周子宫有限元模型,并耦合HybridⅢ5th... 详细信息

为探讨孕妇乘员运输安全下的损伤风险,论文对比研究了常规安全带(三点式)和孕妇专用安全带(组合式)约束系统的防护效果。首先,建立并验证了正面全宽碰撞下后排女性乘员约束系统模型;其次,建立妊娠30周子宫有限元模型,并耦合HybridⅢ5th女性多面体人体模型构建孕妇模型。最后,基于孕妇乘员及胎儿损伤机理,提出了一种用于评价孕妇及胎儿损伤的综合伤害指标WICp(weighted injury criterion of pregnant),研究了不同冲击载荷下孕妇乘员佩戴组合式安全带和三点式安全带的防护效果。研究结果表明:与三点式安全带相比,孕妇乘员佩戴组合式安全带可使孕妇乘员腹部压缩量平均降低38%,子宫壁与胎盘交界面(uterus placental interface,UPI)应变平均降低18.3%,孕妇及胎儿综合伤害平均降低13.4%;当碰撞速度不超过55 km/h时,可使子宫胎盘交界面UPI应变值不超过极限值60%,从而降低了孕妇胎盘早剥风险。研究成果为孕妇乘员及胎儿开发出更安全更可靠更舒适的孕妇专用安全带提供了科学理论依据和参考价值。

关键词：正面冲击孕妇安全带后排乘员碰撞安全损伤防护

Strange star candidates revised within a quark model with chiral mass scaling

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Research in Astronomy and Astrophysics 2011年第4期11卷 482-490页

作者： ang Li Guang-Xiong Peng ju-Fu Lu Department of Physics and Institute of Theoretical Physics and Astrophysics Xiamen University Xiamen 361005 China Department of Physics Graduate University Chinese Academy of Sciences Beijing 100049 China

We calculate the properties of static strange stars using a quark model with chiral mass scaling. The results are characterized by a large maximum mass （-1.6 M⊙） and radius （-10km）. Together with a broad collection of modern neutron star models, we discuss some recent astrophysical observational data that could shed new light on the possible presence of strange quark matter in compact stars. We conclude that none of the present astrophysical observations can prove or confute the existence of strange stars.

关键词： dense matter -- elementary particles -- equation of state -- stars: inte-riors

基于模糊综合评价法的云南观鸟游客满意度研究——以滇西地区为例

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昆明冶金高等专科学校学报 2024年第2期40卷 48-54页

作者：岳茂伟陆敏李奕霏昆明冶金高等专科学校办公室(党委巡察办) 云南昆明650033 昆明冶金高等专科学校马克思主义学院云南昆明650033 云南工商学院文法学院云南昆明651700

观鸟旅游集生态、运动、审美、科普等多种功能于一体,是最具代表性的生态旅游方式之一。最近几年,云南观鸟旅游市场规模越来越大,进行观鸟旅游开发、举办观鸟节等活动的地区也越来越多,每年都吸引了大量游客。以保山、德宏、大理等地为... 详细信息

观鸟旅游集生态、运动、审美、科普等多种功能于一体,是最具代表性的生态旅游方式之一。最近几年,云南观鸟旅游市场规模越来越大,进行观鸟旅游开发、举办观鸟节等活动的地区也越来越多,每年都吸引了大量游客。以保山、德宏、大理等地为代表的滇西地区是目前云南省观鸟热度最高、观鸟点分布最多的地区。通过模糊综合评价的方式,为滇西地区观鸟旅游满意度建立3个层次的指标体系,包含1项总体目标、3项二级指标和13项三级指标。最终得出结论,游客对观鸟旅游景观特别是云南鸟类资源、特色文化体验比较满意,但是对基础设施满意度较低,这方面存在很大的提升空间。相关管理部门应该进一步发扬优势,弥补短板,全面提升游客的满意度,推动滇西地区乃至全省观鸟旅游的进一步发展。

关键词：模糊综合评价观鸟旅游满意度滇西

Hierarchically porous Co@N-doped carbon fiber assembled by MOF-derived hollow polyhedrons enables effective electronic/mass transport:An advanced 1D oxygen reduction catalyst for Zn-air battery

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journal of Energy Chemistry 2023年第1期76卷 117-126,I0004页

作者： yifei Zhang Quanfeng He Zihao Chen Yuqing Chi junwei Sun Ding Yuan Lixue Zhang Industrial Research Institute of Nonwovens&Technical Textiles College of Textiles&ClothingQingdao UniversityQingdao 266071ShandongChina College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071ShandongChina College of Chemistry and Chemical Engineering Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM)Xiamen UniversityXiamen 361005FujianChina

Developing advanced oxygen reduction reaction(ORR)electrocatalysts with rapid mass/electron transport as well as conducting relevant kinetics investigations is essential for energy technologies,but both still face ongoing ***,a facile approach was reported for achieving the highly dispersed Co nanoparticles anchored hierarchically porous N-doped carbon fibers(Co@N-HPCFs),which were assembled by core-shell MOFs-derived hollow ***,the unique one-dimensional(1D)carbon fibers with hierarchical porosity can effectively improve the exposure of active sites and facilitate the electron transfer and mass transfer,resulting in the enhanced reaction *** a result,the ORR performance of the optimal Co@N-HPCF catalysts remarkably outperforms that of commercial Pt/C in alkaline solution,reaching a limited diffusion current density(j)of 5.85 m A cm^(-2)and a half-wave potential(E_(1/2))of 0.831 ***,the prepared Co@N-HPCF catalysts can be used as an excellent air-cathode for liquid/solid-state Zn-air batteries,exhibiting great potentiality in portable/wearable energy ***,the reaction kinetic during ORR process is deeply explored by finite element simulation,so as to intuitively grasp the kinetic control region,diffusion control region,and mixing control region of the ORR process,and accurately obtain the relevant kinetic *** work offers an effective strategy and a reliable theoretical basis for the engineering of first-class ORR electrocatalysts with fast electronic/mass transport.

关键词： Oxygen reduction catalyst Metal-organic frameworks Carbon nanofiber Hierarchically porous structure Diffusion kinetics Zn-air battery