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Tungsten 2024年第2期6卷 293-303页

作者： Hao-Zhe Xu Dong Li Ying Chen pin Fang Xiao-xing Ke Olga Demidenko Yu-Jing Li Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications Experimental Center of Advanced MaterialsSchool of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Scientifi c-Practical Materials Research Centre National Academy of Sciences of Belarus220072 MinskBelarus

Platinum-group-metal-based alloy nanocrystals have been considered as the most effi cient catalysts for oxygen reduction reaction(ORR).However,the poor stability issues limit their further deployment in industrialization.Tungsten oxide(WO_(3))has received attention due to its intrinsic electrochemical stability and proton absorption/desorption capability.In this work,we prepared PtCuNi/WO_(3)/C hybrid catalyst with inter-diff usive alloy/WO_(3)interface on carbon.The catalyst exhibits enhanced activity and stability associated with the WO_(3)content.The characterization results suggest that the increased activity originates from the complementary proton supply of non-stoichiometric H_(x)WO_(3).Moreover,WO_(3)prevents the particle from dissolution and detachment under vigorous electrochemical polarizations.The enhanced stability originates from the electronic interaction established between Pt and W.This work provides new strategies to design high-performance ORR catalysts by taking the merits of WO_(3)。

关键词： Tungsten oxide PtCuNi Interface Electronic interaction

Mechanistic research:Selenium regulates virulence factors,reducing adhesion ability and inflammatory damage of Helicobacter pylori

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World Journal of Gastroenterology 2024年第1期30卷 91-107页

作者： Chun Qin Gan-Rong Huang Ai-xing Guan Wen-Ting Zhou Hao Chen Pei-Pei Luo Xian-Ke Luo Yan-Qiang Huang zan-Song Huang Guangxi Technology Innovation Cooperation Base of Prevention and Control Pathogenic Microbes with Drug Resistance Youjiang Medical University for NationalitiesBaise 533000Guangxi Zhuang Autonomous RegionChina Department of Digestive Diseases Affiliated Hospital of Youjiang Medical University for NationalitiesBaise 533000Guangxi Zhuang Autonomous RegionChina Key Laboratory of the Prevention and Treatment of Drug Resistant Microbial Infecting Youjiang Medical University for NationalitiesBaise 533000Guangxi Zhuang Autonomous RegionChina Department of Pathology Wannan Medical CollegeWuhu 241002Anhui ProvinceChina Department of Gastroenterology Wujin People’s Hospital affiliated to Jiangsu UniversityChangzhou 213004Jiangsu ProvinceChina Department of Gastroenterology Guangzhou Liwan District People's HospitalGuangzhou 510370Guangdong ProvinceChina

BACKGROUND The pathogenicity of Helicobacter pylori is dependent on factors including the environment and the host.Although selenium is closely related to pathogenicity as an environmental factor,the specific correlation between them remains unclear.AIM To investigate how selenium acts on virulence factors and reduces their toxicity.METHODS H.pylori strains were induced by sodium selenite.The expression of cytotoxin-associated protein A(CagA)and vacuolating cytotoxin gene A(VacA)was determined by quantitative PCR and Western blotting.Transcriptomics was used to analyze CagA,CagM,CagE,Cag1,Cag3,and CagT.C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction,and H.pylori colonization,inflammatory reactions,and the cell adhesion ability of H.pylori were assessed.RESULTS CagA and VacA expression was upregulated at first and then downregulated in the H.pylori strains after sodium selenite treatment.Their expression was significantly and steadily downregulated after the 5th cycle(10 d).Transcriptome analysis revealed that sodium selenite altered the levels affect H.pylori virulence factors such as CagA,CagM,CagE,Cag1,Cag3,and CagT.Of these factors,CagM and CagE expression was continuously downregulated and further downregulated after 2 h of induction with sodium selenite.Moreover,CagT expression was upregulated before the 3rd cycle(6 d)and significantly downregulated after the 5th cycle.Cag1 and Cag3 expression was upregulated and downregulated,respectively,but no significant change was observed by the 5th cycle.C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction.The extent of H.pylori colonization in the stomach increased;however,sodium selenite also induced a mild inflammatory reaction in the gastric mucosa of H.pylori-infected mice,and the cell adhesion ability of H.pylori was significantly weakened.CONCLUSION These results demonstrate that H.pylori displayed virulence attenuation after the 10th d of sodium selenite treatment.Sodium s

关键词： Helicobacter pylori Sodium selenite Virulence factors Adherence Inflammation

Changes in the ground surface temperature in permafrost regions along the Qinghaie-Tibet engineering corridor from 1900 to 2014:A modified assessment of CMIP6

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Advances in Climate Change Research 2023年第1期14卷 85-96页

作者： zan-pin xing Lin ZHAO Lei FAN Guo-Jie HU De-Fu ZOU Chong WANG Shu-Ci LIU Er-Ji DU Yao XIAO Ren LI Guang-Yue LIU Yong-ping QIAO Jian-Zong SHI Cryosphere Research Station on the QinghaieTibet Plateau State Key Laboratory of Cryospheric ScienceNorthwest Institute of Eco-Environment and ResourceChinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China School of Geographical Sciences Nanjing University of Information Science&TechnologyNanjing 210044China Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station School of Geographical SciencesSouthwest UniversityChongqing 400715China Department of Environment and Science Queensland GovernmentBrisbaneQLD 4102Australia

Numerous studies were published in the last two decades to evaluate and project the permafrost changes in its thermal state,mainly based on the soil temperature datasets from the Coupled Model Intercomparison Project(CMIP),and discuss the impacts of permafrost changes on regional hydrological,ecological and climatic systems and even carbon cycles.However,limited monitored soil temperature data are available to validate the CMIP outputs,resulting in the over-projection of future permafrost changes in CMIP3 and CMIP5.Moreover,future permafrost changes in CMIP6,particularly over the QinghaieTibet Plateau(QTP),where permafrost covers more than 40%of its territory,are still unknown.To address this gap,we evaluated and calibrated the monthly ground surface temperature(GST;5 cm below the ground surface),which was often used as the upper boundary to simulate and project permafrost changes derived from 19 CMIP6 Earth System Models(ESMs)against in situ measurements over the QTP.We generated the monthly GST series from 1900 to 2014 for five sites based on the linear calibration models and validated them through the three other sites using the same calibration methods.Results showed that all of the ESMs could capture the dynamics of in situ GST with high correlations(r>0.90).However,large errors were detected with a broad range of centred root-mean-square errors(1.14-4.98℃).The Top 5 model ensembles(MME5)performed better than most individual ESMs and averaged multi-model ensembles(MME19).The calibrated GST performed better than the GST obtained from MME5.Both annual and seasonal GSTs exhibited warming trends with an average annual rate of 0.04℃ per decade in the annual GST.The average seasonal warming rate was highest in winter and spring and lowest in summer.This reconstructed GST data series could be used to simulate the long-term permafrost temperature over the QTP.

关键词： Ground surface temperature CMIP6 Cold bias Permafrost Qinghaie-Tibet engineering corridor

An investigation on topologies of hybrid manifold,impinging-jet nozzle and micro-pin-fin heat sinks

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Science China(Technological Sciences) 2024年第4期67卷 1061-1076页

作者： SHI QianLei YAO XiaoLe LIU Qian QIN Le JU xing XU Chao Key Laboratory of Power Station Energy Transfer Conversion and System of MOE North China Electric Power UniversityBeijing 102206China

The hybrid manifold micro-pin-fin(MMPF)heat sink combined nozzle jets is an option for large-scale integrated circuits(LSI).The demond for uniform and ultra-high heat flux removal by MMPF heat sink has not been adequately investigated.This work aims to solve the problem of fluid organization.The proposed basic tiling topologies,including square,regular hexagon,30°rhombus,and 60°rhombus topologies,provide different organized fluid flows and heat transfer patterns.The present study focuses on comparing these topologies according to independent porous medium parameters,such as nozzle pore size D_(Z),flow pore size D_(X,Y),and porosityε.The results show that the square topology achieves the smallest total thermal resistance R_(tot)value of0.0975×10^(-4)K m^2/W,while the hexagon topology achieved the highest value of COP/?T,which was 2033.9 K^(-1).According to the sensitivity analysis results,the optimal total thermal resistance can be obtained by balancing the influences of nozzle pore size,flow pore size,and porosity.The optimal pressure drop can be obtained by maximizing the porosity.

关键词： heat sink ultra-high heat flux manifold micro-pin-fin impinging-jet topology

季节性河流生态补水方案制定与研究——以北方DY河为例

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中国农村水利水电 2024年第3期 41-49页

作者：刘晋苟少杰李兴拼陈可飞珠江水利委员会珠江水利科学研究院广东广州510611

为探讨季节性河流生态补水方案制定的理论技术和方法体系,提出了一种结合生态流量计算与水动力模型的生态补水互馈方法,该方法在水文序列变异诊断的基础上通过计算河道内生态流量过程,为生态补水方案的制定奠定基础;再根据实际生态补水... 详细信息

为探讨季节性河流生态补水方案制定的理论技术和方法体系,提出了一种结合生态流量计算与水动力模型的生态补水互馈方法,该方法在水文序列变异诊断的基础上通过计算河道内生态流量过程,为生态补水方案的制定奠定基础;再根据实际生态补水过程建立并求解河道生态补水的水动力模型,为生态补水演进研究提供模型支撑;最后利用水动力模型对不同补水方案进行补水演进分析,以此得到给定目标下的最佳补水方案,并以北方某季节性河流DY河为例进行了应用分析。研究结果表明:(1)TG水库入库径流序列的变异点为1980年,在此基础上可将径流序列分为天然阶段与人类干扰阶段两部分;(2)生态补水互馈方法得到的生态补水方案不仅可满足河道内生态流量需求,还充分考虑了河道径流过程的年内丰枯变化特征,对认识我国季节性河道的生态流量恢复过程具有重要的科学意义;(3)生态补水互馈方法应用于DY河生态补水工程上效果良好,按照生态补水目标要求得到了满足DY河境内全线通水的生态补水方案,即DY河春季生态补水时,3月至5月的最佳生态补水流量为49.82、27.17、8.67 m^(3)/s。该方法可为后续DY河针对其他补水目标制定对应的生态补水方案,也可为其他流域的季节性河流生态补水方案制定提供新方法与新思路。

关键词：季节性河流水文变异生态流量生态补水

CLDAS地表温度产品在青藏高原多年冻土区的适用性评估与校正

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气候变化研究进展 2024年第1期20卷 10-25页

作者：胡佳怡赵林王翀胡国杰邹德富幸赞品焦梦迪乔永平刘广岳杜二计南京信息工程大学地理科学学院南京210044 南京师范大学地理科学学院南京210023 中国科学院西北生态环境资源研究院/冰冻圈科学国家重点实验室/藏北高原冰冻圈特殊环境与灾害国家野外科学观测研究站兰州730000 中国科学院大学北京100049

青藏高原多年冻土区现有的地表温度数据主要包括点位观测的地表和浅表层地温数据,以及遥感反演、模式模拟和再分析等手段获取和制备的空间数据。中国气象局陆面数据同化系统(CLDAS)数据产品在全国大部分地区的表现较好,但受实测数据稀... 详细信息

青藏高原多年冻土区现有的地表温度数据主要包括点位观测的地表和浅表层地温数据,以及遥感反演、模式模拟和再分析等手段获取和制备的空间数据。中国气象局陆面数据同化系统(CLDAS)数据产品在全国大部分地区的表现较好,但受实测数据稀缺的限制以及对多年冻土特殊下垫面考量不足的影响,该数据在青藏高原多年冻土区的适用性有待进一步评估和修正。文中基于多年冻土区2008—2018年7个站点的逐日连续地表温度定点观测数据,对CLDAS地表温度数据进行评估,分析在不同时期以及不同下垫面类型下,CLDAS地表温度的适用性情况。结果表明:CLDAS在7个站点的地表温度与实测值存在较大偏差(bias=2.09℃,MAE=3.64℃,RMSE=4.67℃,R^(2)=0.83),主要表现为对地表温度的高估。其中,CLDAS在融化期的适用性相对较好,在冻融交替期、冻结期的适用性较差;在高寒荒漠、高寒荒漠草原地区的适用性较好,在高寒沼泽草甸地区的适用性较差。据此,在考虑归一化植被指数(NDVI)、归一化积雪指数(NDSI)、积雪深度、高程、坡度、坡向、土壤质地对地表温度的影响基础上,构建了多元逐步回归校正模型。校正模型考虑了研究区下垫面情况的差异,提高了CLDAS的模拟精度。结果显示,区分冻结期、融化期、交替期构建模型校正的结果优于不考虑冻融期构建的校正模型。区分冻融期分别构建多元逐步回归模型进行校正后,CLDAS地表温度的精度得到了明显提升(bias=-0.11℃,MAE=2.42℃,RMSE=3.23℃,R2=0.89)。

关键词：地表温度 CLDAS 青藏高原适用性评估多元回归校正

巴戟天多糖对炎性微环境牙周膜成纤维细胞FN及FN-EDA表达的影响

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上海口腔医学 2024年第2期33卷 123-129页

作者：张赞戴晶怡蔡红宣司为幸杨静文田亚光海南医学院口腔医学院海南海口570100 北京大学口腔医院修复科北京100080 海南医学院附属海南医院口腔科海南海口570100 海南省人民医院口腔科海南海口570100

目的:探讨巴戟天多糖(morinda officinalis polysaccharides,MOP)对炎性微环境牙周膜成纤维细胞纤连蛋白(fibronectin,FN)及含额外结构域A的纤连蛋白(fibronectin containing extra domain A,FN-EDA)表达的影响。方法:将36只大鼠随机分为对照组(n=12)和模型组(n=24),模型组采用正畸丝结扎法建立牙周炎,3周后每组各取6只大鼠通过Micro-CT确认建模完成;剩余模型组大鼠随机分为牙周炎组、生理盐水组(NS组)和MOP组。MOP组于大鼠左侧上颌第一磨牙腭侧注射MOP(200 mg/kg、3 d,50μL、4周),NS组注射等体积NS,牙周炎组不做任何处理。取大鼠左侧上颌骨组织,采用H-E染色观察牙周组织病理改变,免疫组织化学染色检测FN、FN-EDA的表达。体外培养牙周膜成纤维细胞,CCK-8法检测MOP对细胞活性的影响。将第4代细胞分为对照组、炎症组(10 mg/mL脂多糖)及实验组(12.5μg/mL MOP,12.5μg/mL MOP+10 mg/mL脂多糖)。利用qRT-PCR及Western印迹法检测FN和FN-EDA的表达变化。采用Prism 8.0软件包对数据进行统计学分析。结果:体内实验中,MOP组较牙周炎组和NS组FN-EDA表达显著下降(P<0.05),炎细胞浸润减少;但各组FN表达量未见统计学差异。体外实验中,与对照组相比,炎症组FN-EDA mRNA和蛋白表达量显著增高(P<0.0001);MOP显著降低炎症细胞FN-EDA表达,但对FN表达无明显影响。结论:FN-EDA在炎症牙周膜组织和细胞中表达升高,MOP可能通过下调FN-EDA而发挥炎症抑制作用。

关键词：牙周炎巴戟天多糖纤连蛋白 FN-EDA

超高速激光熔化扫描速度对Al-Mg-Sc高强铝合金性能的影响

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航空材料学报 2024年第1期44卷 133-142页

作者：文聘董子良吴宇董丁炀罗星杜博睿许培鑫陈斐武汉理工大学理学院新材料力学理论与应用湖北省重点实验室武汉430070 中国航发北京航空材料研究院3D打印研究与工程技术中心北京100095 中机新材料研究院郑州有限公司郑州450001 武汉理工大学材料示范学院材料复合新技术国家重点实验室武汉430070

为了明确超高速激光熔化沉积Al-Mg-Sc高强铝合金的沉积态组织及力学性能特征,以7075铝合金为基体,采用自主开发的LDF3000-40型激光熔化沉积设备制备Al-Mg-Sc高强铝合金,探究激光扫描速度对材料微观组织与室温拉伸性能的影响。结果表明:... 详细信息

为了明确超高速激光熔化沉积Al-Mg-Sc高强铝合金的沉积态组织及力学性能特征,以7075铝合金为基体,采用自主开发的LDF3000-40型激光熔化沉积设备制备Al-Mg-Sc高强铝合金,探究激光扫描速度对材料微观组织与室温拉伸性能的影响。结果表明:超高速激光熔化沉积样品均无明显裂纹,但含有少量小尺寸气孔。沉积态组织由细小的α-Al等轴晶及弥散分布的Al_(3)(Sc,Zr)颗粒构成。利用数值模拟进一步研究扫描速度对力学性能的影响,发现在0.1~1 m/s范围内,较高的激光扫描速度能减少粉末材料的堆积,降低沉积层表面的孔隙率,因此可以提高力学性能。沉积态样品最大抗拉强度为303 MPa,断裂伸长率为22.5%。

关键词：超高速激光熔化沉积高强铝合金力学性能数值模拟

高寒山区积雪遥感提取决策树分类模型构建与精度评价

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桂林航天工业学院学报 2024年第1期29卷 19-25页

作者：朱赞孙山林王建琦姚钘桂林航天工业学院航空宇航学院广西桂林541004 广西无人机系统与技术应用重点实验室广西桂林541004

青藏高原位于亚洲中部,是亚洲数十条大江大河的发源地,也被誉为“亚洲水塔”,因此青藏高原的水环境和气候变化对欧亚大陆上的数十个国家的生态环境都有着重大影响.如何高效获取青藏高原积雪覆被数据是目前相关领域研究的热点问题.本研... 详细信息

青藏高原位于亚洲中部,是亚洲数十条大江大河的发源地,也被誉为“亚洲水塔”,因此青藏高原的水环境和气候变化对欧亚大陆上的数十个国家的生态环境都有着重大影响.如何高效获取青藏高原积雪覆被数据是目前相关领域研究的热点问题.本研究以归一化差异雪指数(Normalized Difference Snow Index,NDSI)为基础,针对高原湖泊结冰容易导致运用常规监督分类方法进行遥感影像积雪提取中分类误差较大的问题,构建了针对高寒山区积雪提取的决策树分类模型,并执行获取决策树分类成果.同时以ENVI遥感图像处理平台共提供的6种应用较为成熟的监督分类算法获取的分类成果为对照,并分别统计各分类方法提取成果的总体分类精度(Overall Accuracy)和Kappa系数两个精度验证指标.最后,通过综合分析得出这7种分类方法的综合分类精度,由高到低分别为:专家决策树>最大似然法>支持向量机>神经网络法>马氏距离法>最小距离法>平行六面体法.其中,本研究所构建的决策树分类结果的总体分类精度和Kappa系数分别达到了96.83%和0.96,远高于其他6种常规监督分类方法的精度,验证了该分类模型的精度.

关键词：卫星遥感高寒山区积雪提取决策树分类精度评价

流动注射-鲁米诺-KMnO_(4)化学发光抑制法测定鸡蛋中氟苯尼考残留含量

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化学研究与应用 2024年第5期36卷 971-979页

作者：龙星宇胡梦敖艺张江群韦万丽夏品华贵州师范大学化学与材料科学学院贵州贵阳550025 贵州师范大学山地环境重点实验室贵州贵阳550025

在碱性条件下,基于氟苯尼考会抑制鲁米诺-KMnO4化学发光,并且随着氟苯尼考浓度的增加,其抑制化学发光强度随之增强,从而建立流动注射-鲁米诺-KMnO4化学发光体系检测氟苯尼考的方法。分别探讨试剂用量、蠕动泵流速等参数条件对该发光强... 详细信息

在碱性条件下,基于氟苯尼考会抑制鲁米诺-KMnO4化学发光,并且随着氟苯尼考浓度的增加,其抑制化学发光强度随之增强,从而建立流动注射-鲁米诺-KMnO4化学发光体系检测氟苯尼考的方法。分别探讨试剂用量、蠕动泵流速等参数条件对该发光强度的影响。优化条件下,在1.0×10^(-6)℃~1.0×10^(-4)g·mL^(-1)质量浓度范围内,氟苯尼考质量浓度与相对化学发光强度呈良好的线性关系,方法检出限(3σ)3.0×10^(-7)g·mL^(-1);对质量浓度8.0×10^(-5)g·mL^(-1)的氟苯尼考平行测定11次,RSD为4.88%。结果表明,建立的流动注射-化学发光分析方法简单快速,并将该方法应用于动物源性食品鸡蛋样中兽药氟苯尼考残留的分析,方法灵敏、准确、可靠,结果令人满意。

关键词：流动注射-化学发光法鲁米诺-KMnO4化学发光体系氟苯尼考