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爆炸载荷下拼接陶瓷板膨胀破碎行为及飞散特性研究

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火工品 2024年第1期 65-70页

作者：史安顺洪晓文秦超樊雪飞夏开朗孙素杰中国兵器工业第五二研究所山东烟台264003

为探究不同形状及尺寸的拼接陶瓷板在爆炸载荷下的膨胀破碎行为及飞散特性,对不同类型陶瓷平板药室的爆轰驱动过程进行了仿真,研究了陶瓷破片的粒径分布规律及陶瓷板不同位置处的破片速度和飞散角变化规律。结果表明:不同类型拼接陶瓷... 详细信息

为探究不同形状及尺寸的拼接陶瓷板在爆炸载荷下的膨胀破碎行为及飞散特性,对不同类型陶瓷平板药室的爆轰驱动过程进行了仿真,研究了陶瓷破片的粒径分布规律及陶瓷板不同位置处的破片速度和飞散角变化规律。结果表明:不同类型拼接陶瓷平板的膨胀破碎过程大致相同。拼接陶瓷片数目对陶瓷平板形成的破片数目及质量分布有较大影响,大部分破片对软目标杀伤能力小;陶瓷破片均满足Rosin-Rammler分布且拼接陶瓷片尺寸及形状影响破片的平均特征尺寸系数λ和幂指数系数k。不同类型陶瓷板水平轴向和垂直轴向破片速度变化趋势差异较大,而边缘横向及边缘纵向破片速度变化趋势相同;陶瓷平板不同位置处的破片飞散角均在-1.75~1.75°内变化,因此其杀伤区域有限。

关键词：拼接陶瓷板爆炸载荷膨胀破碎飞散特性爆炸反应装甲

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349单元自适应光学波前处理器

光学精密工程 2018年第5期26卷 1007-1013页

作者：王建立董玉磊姚凯男林旭东杨乐强刘欣悦王亮陈璐中国科学院长春光学精密机械与物理研究所吉林长春130033 中国科学院大学北京100039

为了满足大型地基高分辨率成像望远镜对自适应光学系统校正频率和成像质量的要求,本文设计了一套349单元自适应光学波前处理系统,该系统在349单元变形镜自适应光学系统上实现了1.500Hz的波前校正频率。设计了以控制计算机、FPGA波前斜... 详细信息

为了满足大型地基高分辨率成像望远镜对自适应光学系统校正频率和成像质量的要求,本文设计了一套349单元自适应光学波前处理系统,该系统在349单元变形镜自适应光学系统上实现了1.500Hz的波前校正频率。设计了以控制计算机、FPGA波前斜率处理器、GPU矩阵乘法处理器以及模块化数模转换机箱等作为主要部件的实时波前处理器,报道了349单元变形镜自适应光学系统对动态像差的闭环校正结果,实验中对模拟大气相干长度r_0为6cm,格林伍德频率为1.0Hz的大气湍流实现有效校正,自适应光学系统闭环后,波前像差的1.000帧平均均方根值由1.07λ(中心波长600nm,后同)下降至0.1.λ。本文设计的349单元变形镜自适应光学系统能够在1.500Hz的波前校正频率下有较高的成像质量,波前处理延时优于235μs。功率谱分析结果表明自适应光学系统对1.0Hz以下的波前畸变具有明显的校正效果。

关键词：自适应光学波前处理器地基大口径望远镜变形镜

重庆某农业集中区土壤重金属污染评价与来源解析

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中国土壤与肥料 2024年第7期 10-18页

作者：张雨涵李瑜官开江何向阳鲍丽然王宇罗恺重庆市地质矿产勘查开发局川东南地质大队重庆400038 重庆土地质量地质调查重点实验室重庆400038 重庆市沙坪坝区农业技术服务中心重庆401335

土壤重金属污染问题日益突出,分析土壤重金属污染成因与来源对污染防治和风险管控具有重要的指导意义。选择重庆某农业土壤集中分布区域,综合采用地累积指数、污染负荷指数、相关分析、主成分分析和正定矩阵因子分析等多种方法,开展了... 详细信息

土壤重金属污染问题日益突出,分析土壤重金属污染成因与来源对污染防治和风险管控具有重要的指导意义。选择重庆某农业土壤集中分布区域,综合采用地累积指数、污染负荷指数、相关分析、主成分分析和正定矩阵因子分析等多种方法,开展了土壤重金属污染特征分析、土壤重金属污染评价和重金属来源解析。结果表明,研究区土壤中Cd、Hg、As、Pb、Cr、Cu、Zn和Ni8种重金属元素平均含量均高于重庆市背景值。其中累积程度最高的重金属为Hg,其次为As和Cd,其平均含量分别为重庆市土壤背景值的54.70、3.03和1.50倍。地累积指数统计结果表明,研究区内土壤Hg和As污染程度较深且分布面积较广。污染负荷指数法评价结果表明,研究区土壤重金属以轻微污染和中度污染为主,研究区综合污染负荷指数(P_(zone))为1.76,整体上呈轻微污染。采用正定矩阵因子分析法对重金属来源进行定量解析,结果表明,研究区土壤中As和Pb的积累主要来自于工业活动和交通排放;土壤中Cr、Cu、Zn和Ni主要来源于自然地质背景;土壤Cd的积累与农业生产活动有关;区域Hg污染由汞矿开采引起。

关键词：土壤污染重金属正定矩阵因子分析模型源解析

维普期刊数据库博看期刊

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粉煤灰浆液氨吹脱及其膏体制备特性

中国环境科学 2024年第3期44卷 1386-1396页

作者：李亚娇李泓成王铁鞠恺金鹏康唐仁龙邵小平赵兵朝任武昂西安科技大学建筑与土木工程学院陕西西安710054 陕西彬长矿业集团有限公司陕西咸阳712000 西安交通大学人居环境学院陕西西安710040 西安科技大学能源学院陕西西安710054

为改善含氨粉煤灰对充填膏体性能带来的不利影响,提高粉煤灰的利用率,实验采用空气吹脱粉煤灰浆液的方式进行脱氨,探究吹脱时间、气浆比、固液比、温度和加碱量等影响因素对粉煤灰脱氨率的影响.结果表明,通过响应面优化吹脱条件,控制吹... 详细信息

为改善含氨粉煤灰对充填膏体性能带来的不利影响,提高粉煤灰的利用率,实验采用空气吹脱粉煤灰浆液的方式进行脱氨,探究吹脱时间、气浆比、固液比、温度和加碱量等影响因素对粉煤灰脱氨率的影响.结果表明,通过响应面优化吹脱条件,控制吹脱时间1.、气浆比900、固液比0.21.、温度26.785℃和加碱量1.802%,预测总脱氨率最高达97.1.8%,与实际误差率在2%以内.经优化吹脱后所制备的粉煤灰充填膏体,仅在养护前期有少量的氨气释放,其泵送性能和微观结构相较于原含氨粉煤灰膏体都得到改善,且在养护28d后,抗压强度提升高达57%.

关键词：粉煤灰氨吹脱脱氨率充填膏体膏体特性

Quantile Regression for Thinning-based INAR(1.Models of Time Series of Counts

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Acta Mathematicae Applicatae Sinica 2021年第2期37卷 264-277页

作者： Dan-shu SHENG De-hui Wang {1. Yang Zi-ang WU School of Mathematics Jilin UniversityChangchun 130012China School of Economics Liaoning UniversityShenyang 110036China School of Mathematics and Statistics Changchun University of TechnologyChangchun 130012China

In this paper,we develop the quantile regression(QR)estimation for the first-order integer-valued autoregressive(INAR(1.)models by defining the smoothing INAR(1.*** method is used to derive the QR estimators for the autoregressive coefficient and the quantile of *** consistency and asymptotic normality of the proposed estimators are *** performances of the proposed estimation procedures are evaluated by Monte Carlo *** results show that the proposed procedures perform well for simulations and a real data application.

关键词： INAR(1.process quantile regression parameter estimation jittering

Surface energy and water vapor fluxes observed on a megadune in the Badain Jaran Desert, China

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Journal of Arid Land 2015年第5期7卷 579-589页

作者： HU Wenfeng Wang Nai'ang ZHAO Liqiang NING kai ZHang Xunhe SUN Jie Center for Climate Change and Hydrologic Cycle in Arid Region College of Earth and Environmental Science Lanzhou University College of Geographical Science and Tourism Xinjiang Normal University

The Badain Jaran Desert is the second-largest area of shifting sands in China. Our first measurements of the energy components and water vapor fluxes on a megadune using eddy covariance technology were taken from April 201. to April 201.. The results indicate that the Iongwave and shortwave radiative fluxes exhibited large fluctuations and seasonal dynamics. The total radiative energy loss by Iongwave and shortwave radiation was greater on the megadune than from other underlying surfaces. The radiation partitioning was different in different seasons. The land-atmosphere interaction was primarily represented by the sensible heat flux. The average sensi- ble heat flux （40.1.W/m2） was much larger than the average latent heat flux （1..5 W/m2）. Soil heat flux played an important role in the energy balance. The mean actual evaporation was 0.41.mm/d, and the cumulative actual evaporation was approximately 1.0 mm/a. The water vapor would transport downwardly and appear as dew con- densation water. The amount of precipitation determined the actual evaporation. The actual evaporation was sup- posed to be equal to the precipitation on the megadune and the precipitation was difficult to recharge the ground- water. Our study can provide a foundation for further research on land-atmosphere interactions in this area.

关键词： eddy covariance technology energy and water vapor fluxes precipitation evaporation

Eddy covariance measurements of water vapor and energy flux over a lake in the Badain Jaran Desert,China

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Journal of Arid Land 2018年第4期10卷 517-533页

作者： SUN Jie HU Wenfeng Wang Nai'ang ZHAO Liqiang AN Ran NING kai ZHang Xunhe College of Earth and Environmental Sciences Center for Desert and Arid Region ResearchLanzhou JniversityLanzhou 730000China Center for Central Asian Atmosphere Science Research Urumqi 830002China Fuyang Normal University Fuyang 236037China

Exploring the surface energy exchange between atmosphere and water bodies is essential to gain a quantitative understanding of regional climate change, especially for the lakes in the desert. In this study, measurements of energy flux and water vapor were performed over a lake in the Badain Jaran Desert, China from March 201. to March 201.. The studied lake had about a 2-month frozen period （December and January） and a 1.-month open-water period （February-November）. Latent heat flux （LE） and sensible heat flux （Hs） acquired using the eddy covariance technique were argued by measurements of long＇wave and shortwave radiation. Both fluxes of longwave and shortwave radiation showed seasonal dynamics and daily fluctuations during the study period. The reflected solar radiation was much higher in winter than in other seasons. LE exhibited diurnal and seasonal variations. On a daily scale, LE was low in the morning and peaked in the afternoon. From spring （April） to winter （January）, the diurnal amplitude of LE decreased slowly. LE was the dominant heat flux throughout the year and consumed most of the energy from the lake. Generally speaking, LE was mostly affected by changes in the ambient wind speed, while Hs was primarily affected by the product of water-air temperature difference and wind speed. The diurnal LE and Hs were negatively correlated in the open-water period. The variations in Hs and LE over the lake were differed from those on the nearby land surface. The mean evaporation rate on the lake was about 4.0 mm/d over the entire year, and the cumulative annual evaporation rate was 1.45 mm/a. The cumulative annual evaporation was 1. times larger than the cumulative annual precipitation. Furthermore, the average evaporation rates over the frozen period and open-water period were approximately 0.6 and 5.0 mm/d, respectively. These results can be used to analyze the water balance and quantify the source of lake water in the Badain Jaran Desert.

关键词： eddy covariance energy flux radiation evaporation precipitation lake Badain Jaran Desert

气候变暖对森林生态系统碳汇功能的影响:机制、方法和主要进展

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生态学杂志 2024年第9期43卷 2551-2565页

作者：方运霆刘冬伟段伊行黄凯王文超秦玉婧王盎王超刘娱齐图影森林生态与保育重点实验室(中国科学院) 中国科学院沈阳应用生态研究所沈阳110016 中国科学院大学北京100049 辽宁省稳定同位素技术重点实验室沈阳100016 辽宁清原森林生态系统国家野外科学观测研究站沈阳110016

森林是重要的碳汇,每年吸收化石燃料燃烧释放二氧化碳量的33%。自1.50年来全球气温已经增加了1.1.,未来全球气温可能会增加到2.7~4.8℃。但全球变暖对森林碳汇功能影响方向、程度及其机制存在激烈的争议,严重影响对全球未来气候变化的... 详细信息

森林是重要的碳汇,每年吸收化石燃料燃烧释放二氧化碳量的33%。自1.50年来全球气温已经增加了1.1.,未来全球气温可能会增加到2.7~4.8℃。但全球变暖对森林碳汇功能影响方向、程度及其机制存在激烈的争议,严重影响对全球未来气候变化的预测和政府碳排放控制政策的制定。本文综述了全球变暖对森林生态系统碳汇功能影响的机制、研究方法和主要结论。在此基础上,分析现有研究的不确定性,并提出未来的研究方向。

关键词：气候变暖森林生态系统碳汇控制实验树木生长土壤呼吸物候

Main issues in research and practice of environmental protection for water conservancy and hydropower projects in China

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Water Science and Engineering 2016年第4期9卷 312-323页

作者： ang Chen Miao Wu {1.-qi Chen Zhi-yu Sun Chen Shen Peng-yuan Wang Institute of Hydropower and Environment Research China Three Gorges Corporation School of Civil Engineering Tsinghua University College of Hydrology and Water Resources Hohai University Appraisal Center for Environment and Engineering Ministry of Environmental Protection

In this paper,we generally summarize the main issues in the operational period of water conservancy and hydropower projects in China over the past several ***,the adverse impacts of these projects since the technical guidelines were proposed in 2006 are ***,combined with projects and experience from 2006 to 201.,the four main issues are summarized:(1. There exist many questions in the design and construction of fishways,which are useful for fish migration,and the migration effects are not as expected.(2) Temperature stratification affecting the downstream fish is the major impact of temperature,and alters fish spawning in the reproduction season.(3)Ecological base flow has been one of the primary questions of the last 30 years in China,the greatest related difficulty being quantification of the amount and flow process necessary to satisfy fish life history.(4) Fish habitat protection and restoration are popular topics in recent years with the development of river ecosystem *** habitat loss due to the impacts of dam construction and habitat fragmentation has become more and more *** four issues are now the main difficulties in water project management,and interact with one another to bear combined effects on river *** issues of eco-hydraulic consideration in the design period are the key ***,future priorities for research and practice of environmental protection for water conservancy and hydropower projects in China are *** main purpose of this paper is to enhance the scientific research,monitoring,and assessment of operating effectiveness.

关键词： Temperature stratification Ecological base flow Fish habitat Environmental protection