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The establishment of the normal contact force model for a one‐dimensional sphere chain subjected to impact load

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International Journal of Mechanical System Dynamics 2022年第1期2卷 131-142页

作者： Jun liu Futian Zhao zhimin Xiao Yue Wang Zheng liu Haowen Zheng Institute of Engineering Safety and Disaster Prevention Hohai UniversityNanjingChina College of Civil and Transportation Engineering Hohai UniversityNanjingChina

The normal contact force determines the behavior of a particle system.To investigate the normal contact force in a one‐dimensional sphere chain subjected to impact load,by comparing the simulation results of the existing typical normal contact force models embedded in the discrete element program,an improved normal contact force model was proposed in this paper.The improved model con-sists of two parts:the Cundall model for loading and the Daniel model for unloading.Moreover,a systematic test was designed to verify the accuracy and applicability of the improved model.The results showed that the calculated contact force curves agree well with the experimental results.Furthermore,the improved model is implemented in the solution algorithm without need for complex numerical methods and parameters fitting,leading to more efficient simulations.

关键词： discrete element method experiment and simulation normal contact force one‐dimensional sphere chain

Transcriptome of hepatopancreas in kuruma shrimp Marsupenaeus japonicus under low-salinity stress

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Journal of Oceanology and Limnology 2022年第2期40卷 745-765页

作者： Tingjun CHEN zhimin LI Jianyong liu Caifeng LIANG Le YUAN Guangdong Ocean University Zhanjiang 524088China Guangdong Provincial Shrimp Breeding and Culture Laboratory Guangdong Ocean UniversityZhanjiang 524088China

The kuruma shrimp Marsupenaeus japonicus is one of the most commercially important shrimp species in the world.Low salinity would aff ect the penetration and immunity,and even led to its death of the shrimp.However,little is known about the molecular mechanism of the effect.Therefore,hepatopancreas of M.japonicus reared under low-salinity stress for 6,12,24,48,and 96 h was analyzed and the results were compared with that of the control group using transcriptomics.After removing reads containing adapters,88890960-1051300444 clean reads were generated from 10 libraries in the control group and experimental group.Compared with the control group,811,589,1095,745,and 875 diff erentially expressed genes were obtained in the five treatment groups.The N50 and N90 lengths of the transcripts were 1746 bp and 436 bp,respectively.The top 20 gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways associated with the diff erentially expressed genes were related mainly to osmotic regulation(ion exchange,lipid metabolism and carbohydrate metabolism),immune regulation(cellular and humoral immunity),chitin metabolism,and related functions.The diff erential expression patterns of nine randomly selected genes were confi rmed by quantitative real-time PCR.This is the fi rst report of osmotic regulation-related genes that are diff erentially expressed under low-salinity stress in the hepatopancreas of M.japonicus.Furthermore,we found that M.japonicus initiated its own immune regulation under low-salinity stress.These results will help elucidating the mechanism of osmotic regulation and immune responses in this shrimp species.

关键词： Marsupenaeus japonicus transcriptome osmotic regulation immune responses

Precise genome editing with base editors

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Medical Review 2023年第1期3卷 75-84页

作者： Hongcai liu Yao Zhu Minjie Li zhimin Gu Institute of Systems Medicine Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijingChina Suzhou Institute of Systems Medicine SuzhouJiangsu ProvinceChina Institute of Systems Medicine Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100005China Suzhou Institute of Systems Medicine Suzhou 215123Jiangsu ProvinceChina

Single-nucleotide variants account for about half of known pathogenic genetic variants in human.Genome editing strategies by reversing pathogenic point mutations with minimum side effects have great therapeutic potential and are now being actively pursued.The emerge of precise and effcient genome editing strategies such as base editing and prime editing provide powerful tools for nucleotide conversion without inducing double-stranded DNA breaks(DSBs),which have shown great potential for curing genetic disorders.A diverse toolkit of base editors has been devel-oped to improve the editing effciency and accuracy in different context of application.Here,we summarized the evolving of base editors(BEs),their limitations and future perspective of base editing-based therapeutic strategies.

关键词： adenine base editor base editing clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein cytosine base editor

Strain boosts CO oxidation on Ni single-atom-catalyst supported by defective graphene

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Chinese Chemical Letters 2023年第2期34卷 295-300页

作者： Quanguo Jiang Yushuai Qian Yuqing liu Min Huang zhimin Ao College of Mechanics and Materials Hohai UniversityNanjing 210098China Guangzhou Key Laboratory Environmental Catalysis and Pollution Control Guangdong Key Laboratory of Environmental Catalysis and Health Risk ControlInstitute of Environmental Health and Pollution ControlSchool of Environmental Science and EngineeringGuangdong University of TechnologyGuangzhou 510006China

In order to realize the sulfur and water resistance and facilitate the CO oxidation reactions,the effects of strain on the adsorption of CO,O_(2),SO_(2)and H_(2)O molecules on Ni single-atom-catalyst supported by single-carbon-vacancy graphene(Ni-SG) have been studied based on first principles calculations.It shows that the compressive strain increases the adsorption energies of all above mentioned molecules on Ni-SG,where SO_(2)is adsorbed more strongly on Ni-SG than CO.However,in the presence of tensile strain,the adsorption energies decreases significantly when the molecules(O_(2)and SO_(2)) obtain electrons from NiSG,while the adsorption energies just slightly decrease when the molecules(CO and H_(2)O) lose electrons to Ni-SG,which finally achieves the preferential adsorption of CO and O_(2)molecules on Ni-SG by tensile strain.In addition,with tensile strain increasing to 10%,the rate-limited energy barrier along Eley-Rideal(ER) path monotonically increases from 0.77 eV to 0.98 eV,while the rate-limited energy barrier along Langmuir-Hinshelwood(LH) path monotonically decreases from 0.54 eV to 0.44 eV,indicating that the tensile strain can facilitate the LH mechanism while imped the ER mechanism on Ni-SG.The Hirshfeld charge and orbital levels of O_(2)and CO molecules are modulated by the tensile strain,which plays an important role for the decreasing of energy barriers for CO oxidation.Overall,the tensile strain can enhance the sulfur and water resistance of Ni-SG,as well as boost the CO oxidation reactions.

关键词： Strain effect Ni single-atom-catalyst Preferential adsorption CO oxidation First principles calculations

Experimental study on NO_(x)emission characteristics under oxy-fuel combustion

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Clean Energy 2023年第3期7卷 595-601页

作者： Haibo Wu Zhiyong An Kai Zhang Yu Mao zhimin Zheng Zhaohui liu Tianjin Guoneng Panshan Power Generation Co. LtdTianjin301907China China Energy Investment Corporation Beijing100011China Dongfang Boiler(Group)Co. Ltd.Zigong643001China Anhui University of Technology MaanshanAnhui243099China Huazhong University of Science and Technology WuhanHubei430074China

This study focuses on the emission characteristics of NO_(x)under oxy-fuel combustion conditions.A comparative analysis with air combustion was performed.NO_(x)emission,control measures and influence factors under different working conditions were studied.Experiments were carried out on a 3-MWth test platform and a laboratory platform.The‘π’-type furnace was adopted,with the fur-nace width of 2.6 m,depth of 2.0 m and height of 10.5 m for the 3-MWth coal-fired boiler.NO_(x)emissions at different oxygen concen-trations and different air distribution were investigated;the effects of H2O and CO_(2)concentration on denitrification efficiency and SO_(2)/SO_(3)conversion rate were explored.Experiment results suggest that,compared with air combustion,NO concentration(volume basis)at the furnace outlet under oxy-fuel combustion is higher than that of air combustion,but the amount of NO_(x)emissions in the discharged gas significantly decrease compared to the air combustion conditions.In addition,the formation of NO_(x)can be effectively controlled through staged combustion.Furthermore,the selective catalytic reduction(SCR)denitrification efficiency and the con-version rate of SO_(2)to SO_(3)decreases when the CO_(2)concentration and the H2O content increase,indicating that CO_(2)and H2O have an adverse effect on the performance of the catalyst.Additionally,compared with CO_(2)concentration,H2O content has a greater effect on catalyst performance.

关键词： experimental research NO_(x) oxy-fuel combustion SO_(2)/SO_(3)

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钎焊工艺对双层焊管材料时效性能的影响

热加工工艺 2024年第9期53卷 55-58,63页

作者：刘顺明张志敏龙佳明庞二帅梁斌李悦刘再旺首钢京唐钢铁联合有限责任公司制造部河北唐山063210 首钢集团有限公司技术研究院北京100043

使用退火模拟器对双层焊管用钢带进行热处理,模拟其在不同制管速度、钎焊温度下的钎焊过程。使用拉伸试验机检测不同钎焊温度及不同制管速度下钢带的屈服点延伸率和时效指数,以研究钎焊温度和制管速度对双层焊管材料时效性能的影响。结... 详细信息

使用退火模拟器对双层焊管用钢带进行热处理,模拟其在不同制管速度、钎焊温度下的钎焊过程。使用拉伸试验机检测不同钎焊温度及不同制管速度下钢带的屈服点延伸率和时效指数,以研究钎焊温度和制管速度对双层焊管材料时效性能的影响。结果表明,钎焊温度越高,材料的屈服点延伸率越小,时效指数也越小,制管的抗时效性越好。随着制管速度的提高,钎焊后钢带的屈服点延伸率和时效指数均呈增大趋势,抗时效性变差。这是由于制管生产速度增大,冷却段时间变短,渗碳体析出量减小造成的。钎焊前钢带时效指数为10.6 MPa,模拟钎焊后钢带的时效指数为76.8~104.9 MPa,其抗时效性明显变差。

关键词：双层焊管时效指数钎焊工艺

Fe/Zn共掺杂聚苯胺空气阴极催化剂的制备及表征

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河北大学学报（自然科学版） 2024年第3期44卷 261-268页

作者：柴元吉王涵明刘智民肖龙龙沈哲曦于泊蕖河北大学生态环境系河北保定071002 保定蒙牛饮料有限公司河北保定072450

为解决微生物燃料电池(MFC)阴极催化剂耐久性差、氧还原反应(ORR)动力学缓慢和成本高的问题,制备一种Fe、Zn和N共掺杂的多孔碳作为空气阴极催化剂.电化学研究表明:合成的催化剂Fe/Zn-NC-0.9对氧还原反应具有较好的电催化活性,电荷转移... 详细信息

为解决微生物燃料电池(MFC)阴极催化剂耐久性差、氧还原反应(ORR)动力学缓慢和成本高的问题,制备一种Fe、Zn和N共掺杂的多孔碳作为空气阴极催化剂.电化学研究表明:合成的催化剂Fe/Zn-NC-0.9对氧还原反应具有较好的电催化活性,电荷转移电阻为5.6Ω、交换电流密度为53.3 mV/dec、最大功率密度达到(1253±20)mW/m^(2).此外,还评价了Fe对氧还原反应性能和最大功率密度的影响:中等掺杂含量的Fe对提高催化活性起着至关重要的作用,而Fe和N共掺杂的协同效应促进了阴极性能.

关键词： Fe/Zn-NC ORR 空气阴极微生物燃料电池催化剂

痤疮丙酸杆菌生物膜诱导角质形成细胞发生炎症反应的分子机制研究

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中华皮肤科杂志 2024年第4期57卷 302-308页

作者：裴璐郑娜娜曾荣谢媛媛徐浩翔段志敏刘宇甄李岷中国医学科学院北京协和医学院皮肤病研究所南京210042 南京医科大学附属江宁医院南京211100 江苏省皮肤病与性病分子生物学重点实验室南京210042

目的探讨痤疮丙酸杆菌生物膜诱导人原代角质形成细胞发生炎症反应的分子机制。方法体外构建痤疮丙酸杆菌生物膜模型,激光共聚焦显微镜观察其三维立体结构。将培养的人原代角质形成细胞分成3组:二甲基亚砜(DMSO)对照组(仅加入0.01%DMSO)... 详细信息

目的探讨痤疮丙酸杆菌生物膜诱导人原代角质形成细胞发生炎症反应的分子机制。方法体外构建痤疮丙酸杆菌生物膜模型,激光共聚焦显微镜观察其三维立体结构。将培养的人原代角质形成细胞分成3组:二甲基亚砜(DMSO)对照组(仅加入0.01%DMSO)、痤疮丙酸杆菌悬浮菌组(加入痤疮丙酸杆菌悬浮菌,简称悬浮菌组)、痤疮丙酸杆菌生物膜悬液组(加入痤疮丙酸杆菌生物膜悬液,简称生物膜悬液组)。实时荧光定量PCR(RT-qPCR)检测孵育6 h后各组白细胞介素6(IL-6)、IL-8以及肿瘤坏死因子α(TNF-α)mRNA相对表达水平,酶联免疫吸附试验(ELISA)检测孵育24 h后各组IL-6、IL-8及TNF-α游离蛋白水平,Western印迹法检测角质形成细胞Toll样受体2(TLR2)蛋白表达水平。进一步用TLR2/丝裂原激活蛋白激酶(MAPK)/核因子κB(NF-κB)信号通路关键分子的阻断剂(C29、ST2825、BAY11-7082、SB203580、U0126-EtOH)联合痤疮丙酸杆菌生物膜悬液作用于人原代角质形成细胞,同时设DMSO对照组和痤疮丙酸杆菌生物膜悬液阳性对照组,然后检测IL-6、IL-8及TNF-αmRNA和游离蛋白表达水平。多组间比较采用单因素方差分析,两两多重比较采用Bonferroni法。结果激光共聚焦显微镜下,痤疮丙酸杆菌生物膜形成草坪般的三维立体结构,生物膜生长状态良好。RT-qPCR及ELISA显示,生物膜悬液组、悬浮菌组、DMSO对照组炎症因子IL-6、IL-8、TNF-αmRNA及游离蛋白表达水平差异均有统计学意义(mRNA:F=89.70、312.17、46.09,均P0.05)。Western印迹结果显示,生物膜悬液组和悬浮菌组TLR2蛋白表达均明显高于DMSO对照组。经不同MAPK/NF-κB通路抑制剂预处理及痤疮丙酸杆菌生物膜悬液共孵育,C29组、ST2825组、BAY11-7082组、SB203580组、U0126-EtOH组及DMSO对照组IL-6、IL-8、TNF-αmRNA及游离蛋白表达水平均显著低于生物膜悬液组(均P<0.05)。结论痤疮丙酸杆菌生物膜诱导人角质形成细胞发生炎症反应能力较强,可能通过激活TLR2/MAPK/NF-κB信号通路实现。

关键词：痤疮丙酸杆菌生物膜角蛋白细胞 Toll样受体2 炎症反应 MAPK/NF-κB信号通路

基于改进K-means聚类和皮尔逊相关系数户变关系异常诊断

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电测与仪表 2024年第3期61卷 76-82,152页

作者：周纲黄瑞刘度度张芝敏胡军华高云鹏国网湖南省电力有限公司长沙410004 智能电气量测与应用技术湖南省重点实验室长沙410004 湖南大学长沙410082

用电信息采集系统易出现台区户变关系错误问题,传统诊断技术主要针对少用户台区出现异常用户情况,但对于多达数百用户台区,存在多相邻台区异常用户特征提取难题。文中首先通过主成分分析对GIS系统获取台区总表和用户电表电压数据实现降... 详细信息

用电信息采集系统易出现台区户变关系错误问题,传统诊断技术主要针对少用户台区出现异常用户情况,但对于多达数百用户台区,存在多相邻台区异常用户特征提取难题。文中首先通过主成分分析对GIS系统获取台区总表和用户电表电压数据实现降维,建立改进K-means聚类提取电压数据特征,提出改进皮尔逊相关系数算法分析待检测用户,据此建立基于改进K-means聚类和改进皮尔逊相关系数的户变关系异常诊断方法,实现多异常用户所属正确台区诊断。实际算例分析结果表明,文中提出算法在识别同一台区一个及多个异常用户、不同台区多个异常用户情况下均能有效实现异常用户的准确检测与分析,相比传统检测方法,实现简单且准确性更高。

关键词：户变关系 GIS系统主成分分析改进K-means聚类