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Research on the influence of building convex exit on crowd evacuation and its design optimization

Building Simulation 2022年第4期15卷 669-684页

作者： Jiachen li Jinghong Wang Jia li Zhirong Wang Yan Wang Jiangsu Key Laboratory of Urban and Industrial Safety College of Safety Science and EngineeringNanjing Tech UniversityNanjing 210009China Deportment of Public Administration School of LawNanjing Tech UniversityNanjing 211800China

Building exit has always been an emphasis of research in the field of *** studies on crowd flow characteristics at building evacuation bottlenecks usually focus on plane exit,but insufficient attention has been paid to the characteristics of crowd flow at the convex *** exit can be considered as such a structure like a double-bottleneck linked *** paper aims to study the influence of geometric structure characteristics of the convex exit on crowd evacuation and put forward the optimal design strategy of this structure,so as to improve the efficiency of evacuation in an *** social force model-based software,MassMotion,it is found that convex exit is indeed more efficient and safer than common plane exit in terms of evacuation time and pedestrians'congestion,especially when the desired speed is relatively higher,indicating that convex exits are more suitable for crowd evacuation in case of *** size-related parameters of convex exit are analyzed in detail,namely the width of the bottleneck at passage(W_(p)),the passage width(W),the passage length(L),and the exit width(W_(e)),to find out the optimum design of convex *** research shows that the optimal size ratio is that Wp:W:L:We equals 1.5:1.75:3.5:1,and as the overall magnification of building size and the number of pedestrians increases,the evacuation time gradually tends to a stable value,which indicates that this optimal ratio has good adaptability in size ***,based on the in-depth mechanism of pedestrian flow at the convex exit,three possible application scenarios are proposed to illustrate the feasible optimum design of the convex *** results of this study can provide new ideas for research on the structure of building exits.

关键词： convex exit social force model crowd evacuation MassMotion design optimization

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Responses of biotic interactions of dominant and subordinate species to decadal warming and simulated rotational grazing in Tibetan alpine meadow

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Science China(life Sciences) 2018年第7期61卷 849-859页

作者： Xin'e li Xiaoxue Zhu Shiping Wang Shujuan Cui Caiyun LUO Zhenhua Zhang lirong Zhang lili Jiang Wangwang Lyu Key Laboratory of Alpine ecology and Biodiversity Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Adaptation and evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810008China CAS Center for excellence in Tibetan Plateau earth Science of the Chinese Academy of Sciences Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China Naqu Integrated Observation and Research Station of ecology and environment Tibet University and ITP of CASLahsa 850012China

Warming increases competition among plant species in alpine communities by ameliorating harsh environmental conditions,such as low temperatures. Grazing, as the main human activity, may mitigate the effect of warming, as previously ***, it is critical to refine the effects of warming on biotic interactions among species, for example, by taking the competitive ability of species into consideration. Based on a 10-year warming and grazing experiment in a Tibetan alpine meadow, we evaluated interspecific biotic interactions of dominant and subordinate species, using the approach of interspecific spatial associations. Warming significantly increased competition between subordinate and dominant species as well as among subordinate species, but not among dominant species. Moreover, facilitation of dominant-subordinate species also increased under warming. Simulated rotational grazing had similar effects to warming, with increasing interspecific competition. Our results show that, when studying the effects of warming on biotic interactions among species, it is necessary to characterize different species pairs relative to their competitive ability, and that simulated rotational grazing does not mitigate the effects of warming in the long term. Our results also provide evidence that the spatial pattern of species is a critical mechanism in species coexistence.

关键词： climate warming biotic interactions dominant and subordinate species spatial pattern species coexistence

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Towards understanding the surface rippling process by periodic reciprocal nanoscratching

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Friction 2023年第10期11卷 1815-1828页

作者： Zihan li Yongda YAN Jiqiang WANG Chen li Yanquan GeNG State Key Laboratory of Robotics and Systems Robotics InstituteHarbin Institute of TechnologyHarbin 150080China Center for Precision engineering Harbin Institute of TechnologyHarbin 150001China

The bundle structure formed perpendicular to the scratching direction is a type of wear-induced structure for *** this study,the formation mechanism of bundle structures on polycarbonate(PC)surfaces is investigated by reciprocal scratching *** on the analysis of the morphologies,friction forces,and height signals,the formation of the bundle structure is *** influence of scratching parameters,including the feed value and scratching direction,on the formation of the bundle structure is also *** is found that the bundle structure is accumulated by the continuous stacking of the sample materials plowed by the tip in stick–slip motion,and that the stick–slip behavior is enhanced with increased scratching *** work reproduces the formation process of bundle structure in experiments for the first time and demonstrates that the stick–slip enhancement mechanism exists in the reciprocal scratching process,providing further insight into the friction behavior of polymers.

关键词： atomic force microscopy(AFM) bundle structures stick-slip friction force

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effect of lipopolysaccharide on the hemocyte apoptosis of eriocheir sinensis

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2015年第12期16卷 971-979页

作者： Hai-sheng XU Sun-jian LYU Jie-hao XU Bin-jie LU Jing ZHAO Song li Yi-qun li Yu-yin CHeN College of Animal Sciences Zhejiang University

In the present study, we investigated the possible toxicity mechanism of lipopolysaccharide （LPS） extracted from Gram-negative bacteria in eriocheir sinensis hemocytes. Apoptotic hemocytes and reactive oxygen species （ROS） production induced by the LPS were monitored by the combination of flow cytometry and microscope observation. It was shown that LPS induced serious damage on the DNA and morphological changes in hemocytes, including cell shrinkage, fracture of nucleus membrane, margination, condensation and fragmentation of chromatin, and formation of apoptotic bodies indicating obvious hemocyte apoptosis. As compared with the control group, the apoptotic cell ratio increased to 30.61% and 39.01% after 1-h exposure and 57.72% and 75.01% after 2-h exposure to 1 and 10 μg/ml LPS, respectively （P〈0.05）. Significant outburst of ROS production was observed in LPS-treated hemocytes with approximately 176.6% of relative dichlorofluorescein mean fluorescence at 1-h exposure, followed by a drastic decline （P〈0.05）. These results indicated that LPS would induce oxidative stress on hemocytes from e. sinensis and cause ROS burst, DNA damage, and subsequently apoptosis. The process of ROS-mediated apoptosis might be one of the potential toxicity mechanisms of LPS on crustacean hemocytes.

关键词： Hemocyte eriocheir sinensis lipopolysaccharide Apoptosis Reactive oxygen species

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从厥阴论治恶性肿瘤的核心处方挖掘与机制初探

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中国医药导报 2024年第20期21卷 8-16页

作者：孙可意李忠北京中医药大学东直门医院血液肿瘤科北京100700

目的探讨李忠教授基于厥阴理论辨证论治恶性肿瘤的核心处方,并进行中药含药血清对肿瘤细胞抑制作用的体外实验验证。方法收集李忠教授北京中医药大学东直门医院国际部门诊2022年1月至2023年6月恶性肿瘤患者的处方数据,通过古今医案云平... 详细信息

目的探讨李忠教授基于厥阴理论辨证论治恶性肿瘤的核心处方,并进行中药含药血清对肿瘤细胞抑制作用的体外实验验证。方法收集李忠教授北京中医药大学东直门医院国际部门诊2022年1月至2023年6月恶性肿瘤患者的处方数据,通过古今医案云平台V 2.3.7分析药物频次、性味归经,并进行中药间的聚类分析、关联分析、复杂网络分析,总结核心处方。将8只SPF级6~8周龄SD雄性大鼠按照随机数字表法将其分为实验组、对照组,各4只。分别以2 ml核心处方中药煎剂与同剂量生理盐水灌胃中药组和对照组,连续灌胃7 d,提取含药血清。CCK8法确定含药血清对A549、HepG2细胞的最佳干预浓度与干预时间。设置空白组:完全培养基培养,不加药;中药组:以最佳浓度含药血清进行干预;对照组:以同剂量空白血清进行干预。Transwell实验检测细胞迁移及侵袭能力,流式细胞术进行细胞凋亡及周期检测,Western blot检测细胞凋亡与上皮细胞-间充质转化相关蛋白的表达。结果共纳入8166首处方,药物共300种,用药性温、味甘较多,归经以肝、肺经为多。黄芪、鳖甲、乌梅、山萸肉等16味药物使用频率均>90%。结合聚类分析、复杂网络分析等结果与李忠教授经验,得出平调阴阳法核心处方1首,包括生黄芪、炙黄芪、醋鳖甲、仙鹤草、乌梅、党参、当归、熟地黄、忍冬藤、白芍、穿山龙、浙贝母、僵蚕、生牡蛎、山萸肉。实验研究发现,中药含药血清最佳干预浓度为20%、干预时间为48 h。中药组A549、HepG2细胞的迁移和侵袭能力低于对照组,细胞凋亡率高于对照组,阻滞细胞周期长于对照组,Bcl-2、N-Cadherin、Vimentin表达水平低于对照组,Cleaved-Caspase-3、e-Cadherin表达水平高于对照组(P<0.05)。结论运用数据挖掘可得出从厥阴论治恶性肿瘤的核心处方,处方含药血清可体外抑制肿瘤细胞的增殖、迁移与侵袭,机制可能与促进细胞凋亡、阻滞细胞周期、抑制上皮细胞间充质转化相关。

关键词：厥阴恶性肿瘤核心处方阴阳理论数据挖掘机制

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Solar-wind–magnetosphere energy influences the interannual variability of the northern-hemispheric winter climate

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National Science Review 2020年第1期7卷 141-148页

作者： shengping He Huijun Wang Fei li Hui li Chi Wang Geophysical Institute University of Bergen and Bjerknes Center for Climate Research Key Laboratory of Meteorological Disaster/Collaborative Innovation Center on Forecast and evaluation of Meteorological Disasters Nanjing University of Information Science and Technology Climate Change Research Center Chinese Academy of Sciences Nansen-Zhu International Research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Norwegian Institute for Air Research State Key Laboratory of Space Weather National Space Science Center Chinese Academy of Sciences

Solar irradiance has been universally acknowledged to be dominant by quasi-decadal variability, which has been adopted frequently to investigate its effect on climate decadal variability. As one major terrestrial energy source, solar-wind energy flux into earth’s magnetosphere(ein) exhibits dramatic interannual variation, the effect of which on earth’s climate, however, has not drawn much attention. Based on the einestimated by 3D magnetohydrodynamic simulations, we demonstrate a novelty that the annual mean eincan explain up to 25% total interannual variance of the northern-hemispheric temperature in the subsequent boreal winter. The concurrent anomalous atmospheric circulation resembles the positive phase of Arctic Oscillation/North Atlantic Oscillation. The warm anomalies in the tropic stratopause and tropopause induced by increased solar-wind–magnetosphere energy persist into the subsequent *** to the dominant change in the polar vortex and mid-latitude westerly in boreal winter, a ‘top-down’propagation of the stationary planetary wave emerges in the Northern Hemisphere and further influences the atmospheric circulation and climate.

关键词： solar wind winter climate interannual variability stratosphere

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A Bioinspired Soft Robot Combining the Growth Adaptability of Vine Plants with a Coordinated Control System

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Research 2021年第1期2021卷 1266-1273页

作者： Pengchun li Yongchang Zhang Guangyu Zhang Dekai Zhou Longqiu li State Key Laboratory of Robotics and Systems Harbin Institute of TechnologyHarbinHeilongjiang 150001China

Tip-extending soft robots,taking flexible film or rubber as body material and fluid pressure as input power,exhibit excellent advantages in constrained and cluttered environments for detection and ***,existing soft continuum robots are of great challenges in achieving multiple,mutually independent,and on-demand active steering over a long distance without precise steering *** this paper,we introduce a vine-like soft robot made up of a pressurized thin-walled vessel integrated with the high controllability of a control system with multiple degrees of freedom in three ***,steering and kinematic models to relate the steering angle and robot length to the location of the robot tip are provided,and a dynamic finite element model for analyzing the motion of the spatial consecutive steering is *** demonstrate the abilities of disinfection of the robot moving in a long and tortuous pipeline and detection in a multi-obstacle constrained *** is established that the robot exhibits great advantages in active consecutive steering over a long distance,high controllability in completing more complex path planning,and significant ability of carrying operational tools for ventilation pipeline disinfection and multi-obstacle *** bionic soft robot shows great promise for use in environment sensing,target detecting,and equipment servicing.

关键词： robot Robot obstacle

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酶-化学级联催化制备(S)-烟碱

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精细化工 2024年第1期41卷 127-136页

作者：刘茜琳高静马丽宋浩雷贺莹郑晓冰河北工业大学化工学院天津300400 河北亚诺生物科技有限公司河北石家庄052160

传统(S)-烟碱合成方法步骤复杂且依赖多种化学催化剂。为了实现(S)-烟碱的绿色合成,设计了酶-化学级联途径:首先,构建了亚胺还原酶(IReD)与甲酸脱氢酶(FDH)的偶联体系,以麦斯明为底物合成(S)-降烟碱;然后,将(S)-降烟碱经eschweiler-Cla... 详细信息

传统(S)-烟碱合成方法步骤复杂且依赖多种化学催化剂。为了实现(S)-烟碱的绿色合成,设计了酶-化学级联途径:首先,构建了亚胺还原酶(IReD)与甲酸脱氢酶(FDH)的偶联体系,以麦斯明为底物合成(S)-降烟碱;然后,将(S)-降烟碱经eschweiler-Clarke反应制备(S)-烟碱。通过大肠杆菌宿主分别对IReD和FDH进行表达,得到含酶细胞及酶液,考察了pH和温度对细胞中IReD和FDH酶活力的影响。优化酶催化制备(S)-降烟碱的反应条件,在30℃、pH 7.5条件下,添加质量浓度为30 g/L的麦斯明、600 U/L FDH细胞、900 U/L IReD细胞、0.6 mmol/L NADP^(+)和质量浓度为90 g/L的甲酸钠,(S)-降烟碱的产率>98%,对映体过量(e.e.)值>99%。最后,通过化学法将(S)-降烟碱甲基化得到(S)-烟碱,此步骤产率和e.e.值均达99%以上。

关键词： (S)-烟碱亚胺还原酶甲酸脱氢酶 (S)-降烟碱生物工程

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effects of Stabilization Heat Treatment on Microstructure and Mechanical Properties of Si‑Bearing 15Cr–9Ni–Nb Austenitic Stainless Steel Weld Metal

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Acta Metallurgica Sinica(english Letters) 2023年第4期36卷 637-649页

作者： Yakui Chen Dong Wu Dianzhong li Yiyi li Shanping Lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and engineering University of Science and Technology of ChinaShenyang 110016China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Two 15Cr–9Ni–Nb austenitic stainless steel weld metals with 2.5%Si and 3.5%Si(namely 2.5Si and 3.5Si samples,respectively)were designed and prepared through tungsten inert gas(TIG)welding and then hold at 800℃ or 900℃ for 3 h for *** microstructure and mechanical properties were investigated both for the as-welded and after-stabilization heat treatment(SHT)weld *** are 3.0–4.0%martensite and 2.5–3.5%δferrite in the 2.5Si as-welded weld metal and 6.0–7.0%δferrite in the 3.5Si as-welded weld *** SHT,a large amount of martensite formed in the 2.5Si weld metal,andδ→γtransition occurred during the SHT process both for the 2.5Si and 3.5Si weld *** were a large amount of coarse NbC and few nanoscale NbC in the as-welded weld *** the SHT,a large amount of nanoscale NbC formed in the matrix,while a large number of G phases formed at the austenite grain boundaries and theδ/γ*** decrease in solid solution C andδferrite content led to the decline of the yield strength of the weld metal after *** martensite formed in 2.5Si weld metal after SHT had less effect on strength because of its low carbon *** G phases formed during the SHT reduced the impact energy of the weld metal because it promoted the intergranular fracture,while theδ→γtransition reduced the amount of theδ/γinterfaces and avoided the intergranular fracture,which was beneficial for the impact toughness of the weld metals.

关键词： Austenitic stainless steel Weld metal Stabilization heat treatment Martensite NbC δ→γtransition

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基于改进YOLOv5的路面坑洞检测设计

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现代计算机 2024年第6期30卷 61-64页

作者：周研逸周月娥沈琳芸沈立赵远东南京理工大学紫金学院南京210023

随着道路交通的增加,对于路面检测中目标的准确识别成为了一个重要的研究课题。提出了一种基于改进YOLOv5的目标检测算法,通过优化损失函数来提高路面检测中目标的识别精度。该设计算法对路面坑洞检测准确率达到了89.1%,相较于原始YOLOv... 详细信息

随着道路交通的增加,对于路面检测中目标的准确识别成为了一个重要的研究课题。提出了一种基于改进YOLOv5的目标检测算法,通过优化损失函数来提高路面检测中目标的识别精度。该设计算法对路面坑洞检测准确率达到了89.1%,相较于原始YOLOv5算法提升了7.7个百分点,同时出现漏检现象较少,具有较好的检测精度。结果表明,算法在目标检测任务中取得了较好的效果,准确性和实时性得到较高提升。

关键词：目标检测优化损失函数路面检测改进YOLOv5

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