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Nano Research 2024年第8期17卷 6803-6819页

作者： xiaofeng xiao xiaochun Tian Junpeng Li Fan Yang Rui Bai Feng Zhao Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Microorganisms are rich in heteroatoms,which can be self-doped to form active sites during pyrolysis and loaded on microbederived carbonaceous *** recent years,microbe-derived carbonaceous materials,characterized with abundant selfdoping sites,have been continuously developed as cost-effective electrocatalysts for oxygen reduction reaction(ORR).To fully unlock the catalytic potential of microbe-derived carbonaceous materials,a comprehensive analysis of catalytic sites and mechanisms for ORR is *** paper provides a summary of the ORR catalytic performance of microbe-derived carbonaceous materials reported to date,with a specific focus on the self-doping sites introduced during their pyrolytic *** highlights the mono-or co-doping sites involving nonmetallic elements such as oxygen(O),nitrogen(N),phosphorus(P),and sulfur(S)atoms,as well as covers the doping of metallic iron(Fe)atoms with various coordination configurations in microbe-derived carbonaceous *** the impact of these self-doping sites on ORR catalytic performance can guide the design of doping sites in microbe-derived carbonaceous *** approach has the potential to maximize electrocatalytic activity of microbe-derived carbonaceous materials and contributes to the development of more efficient and cost-effective carbonaceous electrocatalysts.

关键词： electrocatalysis heteroatoms self-doped single atom catalyst microbe-derived carbonaceous material

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自动驾驶车辆换道意图识别研究现状

工程科学学报 2024年第10期46卷 1845-1855页

作者：方华珍刘立顾青肖小凤孟宇北京科技大学机械工程学院北京100083

近年来基于数据驱动的自动驾驶车辆换道意图识别研究取得了显著进展,学者们发布了大量的研究成果.针对该领域面临的一些共性的技术挑战,如换道过程的认定、换道标签的缺失以及数据类别不均衡等问题,从不同的数据驱动方法进行分类,主要... 详细信息

近年来基于数据驱动的自动驾驶车辆换道意图识别研究取得了显著进展,学者们发布了大量的研究成果.针对该领域面临的一些共性的技术挑战,如换道过程的认定、换道标签的缺失以及数据类别不均衡等问题,从不同的数据驱动方法进行分类,主要包括基于传统机器学习、基于深度学习和基于集成学习的换道意图识别方法,对近年来这些方法的研究成果进行了回顾和总结.关于换道行为的认定,存在两种主流方案,即车辆穿越车道线和未穿越车道线.对于未穿越车道线的车辆,主要应用于驾驶者换道意图的早期识别方法;而当车辆穿越过车道线时,则通常被用于完整的换道过程的识别.在换道意图标注的研究中,研究者们针对固定时间窗口和航向角阈值对标注精度的影响进行了深入探讨.为了找到最优参数,如最佳的固定时间窗口和航向角阈值,研究者们采用了网格搜索进行寻优.虽然这种方法在固定的驾驶场景中表现良好,但在不同的驾驶场景中,如何实现参数的自适应调节仍然是一个挑战.针对换道数据类别不均衡的问题,研究者采用两种策略:一是调整数据采样方法,利用欠采样和过采样技术平衡各类别样本数量;二是采用对不均衡数据适应性强的分类模型,如集成学习算法或代价敏感学习,以维持较好的分类性能.

关键词：交通工程自动驾驶车辆数据驱动换道意图识别

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少腹逐瘀汤联合穴位贴敷对寒凝血瘀型痛经的治疗效果

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华夏医学 2024年第3期37卷 175-179页

作者：邱晶肖孝凤肖招华新余市中医院

目的探讨中药少腹逐瘀汤联合穴位贴敷治疗寒凝血瘀型痛经的临床效果。方法选取2019年11月至2020年10月在新余市中医院就诊的80例寒凝血瘀型痛经患者为研究对象，应用随机数字表法将其分为对照组和观察组，每组40例。对照组予以少腹逐... 详细信息

目的探讨中药少腹逐瘀汤联合穴位贴敷治疗寒凝血瘀型痛经的临床效果。方法选取2019年11月至2020年10月在新余市中医院就诊的80例寒凝血瘀型痛经患者为研究对象，应用随机数字表法将其分为对照组和观察组，每组40例。对照组予以少腹逐瘀汤治疗，观察组在对照组基础上加用穴位敷贴治疗。比较两组视觉模拟疼痛评分法(VAS)评分、痛经症状评分、血液流变学指标及治疗总有效率。结果治疗后，两组VAS评分、痛经症状评分均低于治疗前，且观察组评分低于对照组，差异有统计学意义(P<0.05);两组红细胞压积、全血高切、血浆黏度水平均低于治疗前，且观察组低于对照组(P<0.05);观察组治疗总有效率92.5%高于对照组85.0%(P<0.05)。结论寒凝血瘀型痛经患者应用少腹逐瘀汤联合穴位贴敷治疗，能有效促进血液循环，缓解经期腹痛，提高治疗效果。

关键词：少腹逐瘀汤穴位贴敷痛经寒凝血瘀型

典型玉米种植小流域中乙草胺对水生生物的环境风险评估

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生态毒理学报 2024年第4期19卷 175-181页

作者：黄怡韩兵肖晓峰王宝成王力明杨白驹于洋北京市污染源管理事务中心北京100089 生态环境部固体废物与化学品管理技术中心北京100029

乙草胺是北京市主要粮食作物玉米的常用苗前除草剂,其在环境中的残留可能导致水生生物生存、生长和繁殖等方面的不利影响。为评估北京市某典型玉米农业小流域中乙草胺对水生生物的环境风险,本研究利用超高效液相色谱-串联质谱对地表水... 详细信息

乙草胺是北京市主要粮食作物玉米的常用苗前除草剂,其在环境中的残留可能导致水生生物生存、生长和繁殖等方面的不利影响。为评估北京市某典型玉米农业小流域中乙草胺对水生生物的环境风险,本研究利用超高效液相色谱-串联质谱对地表水样品进行分析测试,获取乙草胺在水环境中的暴露浓度,利用水生生物毒性数据推算乙草胺的预测无效应浓度,并开展风险表征。结果表明,乙草胺在水环境中的浓度范围为ND~0.034μg·L^(-1),即实测环境暴露浓度取0.034μg·L^(-1)。获得乙草胺对藻类、溞类、鱼类3个营养级水生生物的危害数据,推算出乙草胺的预测无效应浓度为0.052μg·L^(-1)。经风险表征发现,该区域乙草胺的使用对水生生物的风险可接受。

关键词：乙草胺风险评估环境监测

Characteristics and influencing factors of CO_(2) emission from inland waters in China

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Science China Earth Sciences 2024年第6期67卷 2034-2055页

作者： Ting ZHOU xiaofeng WANG Zuolin xiao Zhaoyin QING Xianxiang LI Jilong WANG Ziyi QUE Chongqing Key Laboratory of Carbon Cycling and Carbon Regulation in Mountainous Ecosystems Chongqing 401331China School of Geography and Tourism Chongqing Normal UniversityChongqing 401331China Chongqing Field Observation and Research Station of Earth Surface Ecological Processes in Three Gorges Reservoir Area Chongqing 405400China School of Earth System Science Tianjin UniversityTianjin 300072China

Inland water bodies,being the most active biogeochemical cycle reactors,play a pivotal role in the global carbon cycle and CO_(2) *** study integrates existing observation dataset of CO_(2) flux(fCO_(2))in rivers,lakes and reservoirs in China,to elucidate their spatial-temporal patterns and key influencing factors and to reappraise the significance for regional carbon *** showed that,the fCO_(2) in rivers,lakes and reservoirs in China presented significant variability with large range of-379.3-4947.6,-160.1-785.0 and -74.0-1603.1 mg CO_(2)m-2h^(-1),*** median of the fCO_(2) in rivers was of 228.5 mg CO_(2)m^(-2)h^(-1),observably higher than these in lakes and reservoirs(26.0 and 28.3 mg CO_(2)m^(-2)h^(-1),respectively).The fCO_(2)in rivers and reservoirs exhibited similar decreasing trend from south to north as a result of universal climate restraint,the averaged fCO_(2) in Pearl River and Yangtze River basins showed much higher than that in Northeastern ***,the averaged fCO_(2) in the Mongolia-Xinjiang lake district and the Northeast lake district were higher than other lake districts,followed by the Qinghai-Xizang lake district,and the Eastern and Yungui lake district were generally low,contradicting the climatic *** water primary production enhancement resulting from human activities was the main driver of spatial variation in the fCO_(2) in ***,the fCO_(2) in rivers presented seasonal pattern with higher wet season than dry season,while opposite patterns were found in lakes and *** temperature,precipitation and water primary production were main ***,it showed pH was a key factor indicating the variability of the fCO_(2) levels either in rivers,lakes or in *** lakes,the fCO_(2) is closely linked to chlorophyll a(Chl-a)and dissolved oxygen(DO),whereas,the fCO_(2) in rivers is primarily associated with organic carbon(OC)and total nitrogen(TN),highlighting the dive

关键词： Rivers/lakes/reservoirs CO_(2) emission Spatio-temporal variability Influence factors Regional contribution

Synergistic Promotion of Electrical, Mechanical and Thermal Properties for Silicone Rubber-based Field Grading Material via Compound Modification

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 337-350页

作者： Jiale Wu Yangzhi Gong Peiqi Xiong Zexi Xing xiaofeng Xue xiao Yang Boyang Shen Xingming Bian State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University102206 BeijingChina State Grid Fuzhou Electric Power Supply Company Fuzhou 350009Fujian ProvinceChina Electrical Engineering Division University of CambridgeCambridge CB30FAUK

Use of nonlinearconductive SiC/silicone rubber(SR)field grading material(FGM)can improve the local field concentration of composite *** large volume fraction and large-size SiC particles(SiCp)into SR can obtain a good field grading effect,but it is accompanied by the deterioration of mechanical *** SiC with different shapes can solve this *** incorporating one-dimensional SiC whiskers(SiCw)to synergize with granular SiCp,SiC/SR FGM with better field-dependent conductivity,mechanical properties and thermal conductivity than large-size SiCp and large volume fraction filling case can be obtained by using smaller size SiCp and lower filling *** simulations of 500 kv line insulators show that the modified SiC/SR FGM can reduce the maximum field strength along the insulator surface and at sheath-core rod interfaces by 55%and 71.4%,*** combined application of FGM and grading ring can achieve a complementary *** FGM to partially replace the role of the grading rings,the field strength indicators can still meet the operational requirements after the tube radius and shielding depth of the grading rings at both ends are reduced by 36.2%and 40%separately,which is a benefit to alleviating the problems of high weight and large volume faced by traditional field grading methods.

关键词： Compound modification electric field regulation field grading material field-dependent conductivity mechanical properties thermal conductivity

Visible light induces bacteria to produce superoxide for manganese oxidation

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Frontiers of Environmental Science & Engineering 2023年第2期17卷 59-69页

作者： Fan Yang Junpeng Li Huan Wang xiaofeng xiao Rui Bai Feng Zhao CAS Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Manganese oxides are widely distributed in soils and sediments, affecting the migration and transformation of heavy metals and organic pollutants. The microbial conversion of soluble Mn(Ⅱ) into insoluble Mn(Ⅲ/Ⅳ) oxides is considered to be the initial source of manganese oxides in the environment;however, whether this process is related to a physiological role remains unclear. Here, we explored the microbial manganese oxidation process under visible light by using coastal surface seawater microorganisms. Visible light greatly promotes the oxidation rate of Mn(Ⅱ), and the average rate reaches 64 μmol/(L·d). The generated manganese oxides were then conducive to Mn(Ⅱ) oxidation, thus the rapid manganese oxidation was the result of the combined action of biotic and abiotic, and biological function accounts for 88 % ± 4 %. Extracellular superoxide produced by microorganisms induced by visible light is the decisive factor for the rapid manganese oxidation in our study. But the production of these superoxides does not require the presence of Mn(Ⅱ) ions, the Mn(Ⅱ) oxidation process was more like an unintentional side reaction, which did not affect the growth of microorganisms. More than 70 % of heterotrophic microorganisms in nature are capable of producing superoxide, based on the oxidizing properties of free radicals, all these bacteria can participate in the geochemical cycle of manganese. What’s more, the superoxide oxidation pathway might be a significant natural source of manganese oxide.

关键词： Mn(Ⅱ)oxidation Manganese-oxidizing bacteria Reactive oxygen species Mn(Ⅲ/Ⅳ)oxides

Processing Constrained K Closest Pairs Query in Spatial Databases

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Wuhan University Journal of Natural Sciences 2006年第3期11卷 543-546页

作者： LIU xiaofeng LIU Yunsheng xiao Yingyuan College of Computer Science and Technology Huazhong University of Science and Technology Wuhan 430074Hubei China

In this paper, constrained K closest pairs query is introduced, wbich retrieves the K closest pairs satisfying the given spatial constraint from two datasets. For data sets indexed by R trees in spatial databases, three algorithms are presented for answering this kind of query. Among of them, two-phase Range＋Join and Join＋Range algorithms adopt the strategy that changes the execution order of range and closest pairs queries, and constrained heap-based algorithm utilizes extended distance functions to prune search space and minimize the pruning distance. Experimental results show that constrained heap-base algorithm has better applicability and performance than two-phase algorithms.

关键词： spatial databases query processing R-tree closest pairs query constrained closest pairs query

Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

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International Journal of Coal Science & Technology 2024年第3期11卷 1-31页

作者： Chaojun Fan Hao Sun Sheng Li Lei Yang Bin xiao Zhenhua Yang Mingkun Luo xiaofeng Jiang Lijun Zhou College of Mining Liaoning Technical UniversityFuxin123000China College of Safety Science and Engineering Liaoning Technical UniversityFuxin123000China Energy Business Department Shanxi Lu’an Chemical GroupChangzhi046200China

With the continuous increase of mining in depth,the gas extraction faces the challenges of low permeability,great ground stress,high temperature and large gas pressure in coal *** controllable shock wave(CSW),as a new method for enhancing permeability of coal seam to improve gas extraction,features in the advantages of high efficiency,eco-friendly,and low *** order to better utilize the CSW into gas extraction in coal mine,the mechanism and feasibility of CSW enhanced extraction need to be *** this paper,the basic principles,the experimental tests,the mathematical models,and the on-site tests of CSW fracturing coal seams are reviewed,thereby its future research directions are *** on the different media between electrodes,the CSW can be divided into three categories:hydraulic effect,wire explosion and excitation of energetic materials by detonating *** the process of propagation and attenuation of the high-energy shock wave in coal,the shock wave and bubble pulsation work together to produce an enhanced permeability effect on the coal *** stronger the strength of the CSW is,the more cracks created in the coal is,and the greater the length,width and area of the cracks *** repeated shock on the coal seam is conducive to the formation of complex network fracture system as well as the reduction of coal seam strength,but excessive shock frequency will also damage the coal structure,resulting in the limited effect of the enhanced gas *** the influence of ground stress,the crack propagation in coal seam will be *** difference of horizontal principal stress has a significant impact on the shape,propagation direction and connectivity of the CSW induced *** permeability enhancement effect of CSW is affected by the breakage degree of coal *** shock wave is absorbed by the broken coal,which may hinder the propagation of CSW,resulting in a poor effect of permeability *** arranging two a

关键词： Controllable shock wave Permeability enhancement Gas extraction Basic principle Experimental test Mathematical models On-site test

The Geology, Fluid Inclusions, and O-S Isotopes of the Mibei Gold Deposit, Hunan Province, Southern China

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 992-1006页

作者： XUE Wenhao LIANG Yayun LI xiaofeng LI Mingyi XIE Wenbo PENG Xue XIA Rui HE Hongsheng xiao Jincheng School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Geophysical and Geochemical Survey Institute of Hunan Changsha 410116China New Geological Energy Exploration and Development Engineering Technology Research Center of Hunan Changsha 410116China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences(Beijing)Beijing 100083China Comprehensive Survey Command Center for Natural Resources China Geological SurveyBeijing 100055China

The Mibei gold deposit,located in the southwestern part of the Xuefengshan uplift zone,the middle section of the Jiangnan orogenic belt in southern China,has estimated gold resources of approximately seven *** deposit is primarily a quartz vein-type gold deposit,with ore bodies occurring mainly within Neoproterozoic *** main metallic minerals in the ore are pyrite,chalcopyrite,and *** this study,the petrography and microthermometry of ore-forming fluid inclusions,oxygen isotopes of gold-bearing quartz,and sulfur isotopes of goldbearing sulfides and arsenopyrite were *** types of fluid inclusions were identified:type Ⅰa three-phase inclusions comprising vapor and two phases of liquids(V_(CO_(2))+L_(CO_(2))+L_(H2O)),type Ⅰb two-phase liquids(L_(CO_(2))+L_(H2O)),typeⅡ two-phase vapor-rich inclusions(V/V+L> 50%),and type Ⅲ pure liquid *** Ⅰ inclusions were heated uniformly to the liquid phase,type Ⅱ inclusions were heated uniformly to the gas phase,and type Ⅲ inclusions were heated without *** general,the temperature range of homogenization to liquid phase of fluid inclusions in the Mibei gold deposit is 204-227℃.The salinity of the inclusion ranges from 4.6 to 12.2 wt% NaCl *** δ~(18)O_(SMOW) of gold-bearing quartz varies from 16.9‰ to 17.5‰.The δ~(18)O_(H2O) of gold-bearing quartz are varied from 6.5‰ to 7.5‰.The δ~(34)S values of gold-bearing pyrite range from 1.7‰ to 6.8‰.The δ~(34)S values of gold-bearing arsenopy rite range from 5.6%o to 5.9‰.Theδ~(34)S values of pyrite from wall rocks slate range from 6.4‰ to 11.6‰.This evidence implies that the ore-forming fluids of the Mibei gold deposit originated from magmatic-hydrothermal processes,mixing with minor S from the surrounding *** with the evolution of the Jiangnan orogenic belt,due to the magmatic and tectonic activities of the Xuefengshan uplift during the Caledonian period,the fault seal mechanism controlled the ore-forming p

关键词： ore-forming fluid ore genesis Mibei gold deposit Xuefengshan uplift zone Jiangnan orogenic belt