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Estimation of carbon storage based on individual tree detection in Pinus densiflora stands using a fusion of aerial photography and LiDAR data 被引量:9
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作者 KIM So-Ra KWAK Doo-Ahn +4 位作者 LEE Woo-Kyun SON Yowhan BAE Sang-Won KIM Choonsig YOO Seongjin 《Science China(Life Sciences)》 SCIE CAS 2010年第7期885-897,共13页
The objective of this study was to estimate the carbon storage capacity of Pinus densiflora stands using remotely sensed data by combining digital aerial photography with light detection and ranging(LiDAR) data.A digi... The objective of this study was to estimate the carbon storage capacity of Pinus densiflora stands using remotely sensed data by combining digital aerial photography with light detection and ranging(LiDAR) data.A digital canopy model(DCM),generated from the LiDAR data,was combined with aerial photography for segmenting crowns of individual trees.To eliminate errors in over and under-segmentation,the combined image was smoothed using a Gaussian filtering method.The processed image was then segmented into individual trees using a marker-controlled watershed segmentation method.After measuring the crown area from the segmented individual trees,the individual tree diameter at breast height(DBH) was estimated using a regression function developed from the relationship observed between the field-measured DBH and crown area.The above ground biomass of individual trees could be calculated by an image-derived DBH using a regression function developed by the Korea Forest Research Institute.The carbon storage,based on individual trees,was estimated by simple multiplication using the carbon conversion index(0.5),as suggested in guidelines from the Intergovernmental Panel on Climate Change.The mean carbon storage per individual tree was estimated and then compared with the field-measured value.This study suggested that the biomass and carbon storage in a large forest area can be effectively estimated using aerial photographs and LiDAR data. 展开更多
关键词 LiDAR AERIAL PHOTOGRAPH region GROWING marker-control WATERSHED segmentation carbon storage
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Impact of Planted Mangrove Species on Biomass Carbon and Other Structural Attributes in Ayeyarwady Region
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作者 Aung Wunna Tun Wai Nyein Aye 《Open Journal of Forestry》 2024年第1期98-116,共19页
This study examines the impact of different mangrove species on the structure and carbon storage potential of mangrove stands in Myanmar. We focused on three species: Avicennia officinalis, Avicennia marina and Brugui... This study examines the impact of different mangrove species on the structure and carbon storage potential of mangrove stands in Myanmar. We focused on three species: Avicennia officinalis, Avicennia marina and Bruguiera sexangula. These species were selected for their fast growth, ability to protect against cyclones, and effectiveness in coastal defense during mangrove restoration. To collect data on tree structure and carbon storage, we conducted field surveys measuring parameters such as diameter at breast height (DBH), tree height and crown diameter for each tree. Non-destructive methods were used for data collection. Using ANOVA and post-hoc multiple comparison tests, we assessed differences in structure and carbon stock among the three species. Regression analysis was also performed to understand the relationship between carbon stock and structural attributes. In terms of stand densities, we observed variations among species, with pioneer stage plantations exhibiting higher densities compared to mature stands. Seedlings showed sufficient regeneration, supporting the sustainability of the forest. Biomass accumulation varied across species, with A. officinalis having the highest average biomass. Aboveground biomass showed a strong correlation with basal area. A. officinalis had the highest total biomass carbon accumulation at 55.29 ± 20.91 Mg C ha<sup>-1</sup>, with 77.43% aboveground carbon and 22.57% belowground carbon. A. marina stored 41.09 ± 11.03 Mg C ha<sup>-1</sup>, with a similar distribution of 76.05% aboveground and 23.95% belowground carbon, while B. sexangula stored 23.23 ± 3.12 Mg C ha<sup>-1</sup>, with 70.70% aboveground carbon and 29.30% belowground carbon. The amount of aboveground carbon was a significant portion of the overall carbon storage and correlated with tree density, diameter, basal area and height. Our findings highlight the importance of selecting suitable species and considering structural attributes for mangrove restoration and carbon storage efforts. These results provide v 展开更多
关键词 Species Selection BIOMASS Carbon storage Ayeyarwady region Myanmar
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State-of-charge Balance Control and Safe Region Analysis for Distributed Energy Storage Systems with Constant Power Loads
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作者 Yijing Wang Yangzhen Zhang +1 位作者 Zhiqiang Zuo Xialin Li 《CSEE Journal of Power and Energy Systems》 SCIE EI CSCD 2024年第4期1733-1745,共13页
This paper presents a fully distributed state-of-charge balance control (DSBC) strategy for a distributed energy storage system (DESS). In this framework, each energy storage unit (ESU) processes the state-of-charge (... This paper presents a fully distributed state-of-charge balance control (DSBC) strategy for a distributed energy storage system (DESS). In this framework, each energy storage unit (ESU) processes the state-of-charge (SoC) information from its neighbors locally and adjusts the virtual impedance of the droop controller in real-time to change the current sharing. It is shown that the SoC balance of all ESUs can be achieved. Due to virtual impedance, voltage deviation of the bus occurs inevitably and increases with load power. Meanwhile, widespread of the constant power load (CPL) in the power system may cause instability. To ensure reliable operation of DESS under the proposed DSBC, the concept of the safe region is put forward. Within the safe region, DESS is stable and voltage deviation is acceptable. The boundary conditions of the safe region are derived from the equivalent model of DESS, in which stability is analyzed in terms of modified Brayton-Moser's criterion. Both simulations and hardware experiments verify the accuracy of the safe region and effectiveness of the proposed DSBC strategy. 展开更多
关键词 Constant power load(CPL) distributed control distributed energy storage system(DESS) safe region state-of-charge(SoC)
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低温环境下考虑电池寿命的微电网优化调度
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作者 丁佳昀 胡秦然 +2 位作者 吴在军 钱涛 侯凯 《中国电机工程学报》 EI CSCD 北大核心 2024年第10期3815-3823,I0006,共10页
储能系统作为微电网重要组成部分,为微电网协调能量供需提供了解决方案。然而,在低温环境下,储能系统中电池寿命的快速衰减严重影响了系统的经济性和安全性。因此,该文提出一种低温环境下考虑电池寿命的微电网优化调度混合整数模型,来... 储能系统作为微电网重要组成部分,为微电网协调能量供需提供了解决方案。然而,在低温环境下,储能系统中电池寿命的快速衰减严重影响了系统的经济性和安全性。因此,该文提出一种低温环境下考虑电池寿命的微电网优化调度混合整数模型,来仿真微电网优化调度过程和高效计算储能充放电计划。首先,基于阿伦尼乌斯方程,分析低温环境中电池寿命的受影响机理;接着,采用考虑充放电次数和放电深度的电池寿命方程,构建电池全温度范围的老化模型;最后,构建考虑电池自发热和全温度范围的寿命衰减模型,并通过可行域凸极点组合方法对模型进行转化和简化,来避免模型中非线性项目导致无法获得全局最优解的困境。算例验证和对比分析表明,该文提出的模型能在低温环境中降低系统运行成本,减缓电池衰减速率,延长近一倍的电池寿命。 展开更多
关键词 电池储能 电池寿命 低温环境 微电网优化调度 可行域
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喀斯特富营养湖泊水体碳浓度及储量变化特征——以异龙湖为例
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作者 王旭 温雯雯 +6 位作者 郭雯 李平 王明果 黄林培 王露 杨关绍 陈光杰 《地理研究》 CSCD 北大核心 2024年第5期1316-1333,共18页
为探究喀斯特富营养湖泊水体不同赋存形式碳浓度和碳储量动态变化模式及其影响因素,本研究于2021年9月—2022年6月对异龙湖开展4个季节、20个点位的水质和水体碳浓度时空分布特征研究。结果发现,异龙湖水体碳以溶解碳占主导,溶解无机碳(... 为探究喀斯特富营养湖泊水体不同赋存形式碳浓度和碳储量动态变化模式及其影响因素,本研究于2021年9月—2022年6月对异龙湖开展4个季节、20个点位的水质和水体碳浓度时空分布特征研究。结果发现,异龙湖水体碳以溶解碳占主导,溶解无机碳(DIC)浓度在4种赋存形式碳中最高为(41.26±4.93)mg/L,溶解有机碳(DOC)次之为(16.23±2.23)mg/L,颗粒碳浓度相对较低,颗粒有机碳(POC)和颗粒无机碳(PIC)浓度分别为(10.05±1.81)mg/L和(0.82±0.56)mg/L。异龙湖全年水体碳储量平均值为5.30 Gg C,4种赋存形式碳储量占比分别为60.57%(DIC)、23.77%(DOC)、14.53%(POC)和1.13%(PIC)。分析表明,异龙湖DOC、POC浓度与营养盐负荷及藻类生物量有关,指示其主要来源于藻源性有机碳。DIC浓度与DOC、水温、氨氮、入湖河流分布等因素相关,表明DIC受矿化作用、水温及流域水体稀释作用的共同驱动。PIC浓度与叶绿素a浓度和酸碱度有关,指示其主要受藻类光合作用导致的酸碱平衡破坏影响。异龙湖不同赋存形式碳浓度间存在一定的耦合关系,反映了不同赋存形式水体碳存在迁移和转化,湖泊富营养化导致藻类生物量增加,造成有机碳浓度POC和DOC同步升高,同时有机质的矿化作用也引起无机碳与有机碳的协同变化。与其他湖泊相比,异龙湖具有更高的水体碳浓度水平,可能与异龙湖的富营养化、喀斯特地质背景以及特殊的地理位置等因素有关。在碳储量上,水量是影响湖泊水体碳储量的关键因素,而富营养化提高了水体碳浓度和碳累积速率,增强了湖泊的碳汇效应,在全球湖泊富营养化问题日趋严峻的背景下,湖泊水体碳储量在生态系统碳汇估算中的地位逐渐显露。 展开更多
关键词 水体碳浓度 水体碳储量 喀斯特地区 富营养化 异龙湖
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以碳增汇为导向的县域国土空间生态修复研究——以中国新疆维吾尔自治区温宿县为例
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作者 张謦文 杨颖 +2 位作者 袁艺 韩静怡 李迪华 《景观设计学(中英文)》 CSCD 2024年第3期10-35,共26页
面对全球气候变化,亟需将“双碳”目标纳入国土空间规划实践。目前,以碳增汇为导向,针对中国西部地区、特别是西北干旱区县域的生态修复研究较少。本研究以中国新疆维吾尔自治区温宿县为例,从碳吸收能力与碳储量两方面综合评估温宿县碳... 面对全球气候变化,亟需将“双碳”目标纳入国土空间规划实践。目前,以碳增汇为导向,针对中国西部地区、特别是西北干旱区县域的生态修复研究较少。本研究以中国新疆维吾尔自治区温宿县为例,从碳吸收能力与碳储量两方面综合评估温宿县碳汇现状,并以此为基础识别温宿县碳汇空间格局,探索以碳增汇为导向的县域国土空间生态修复规划的途径。现状评估结果表明,温宿县的碳汇重要性在不同地理区域呈现出较大差异。在研究区域内识别出一处碳汇腹地、两处碳汇重要区,以及总面积达2259.81km^(2)的碳汇潜力带,进而结合土地利用现状提炼出8种土地利用典型空间模型,并拟定了相应的生态修复策略。研究有助于促进“双碳”目标在国土空间规划中的落实,对中国西北干旱区域碳汇管理实践具有积极意义,并可为地理条件相似的地区提供固碳增汇的经验。 展开更多
关键词 碳增汇 碳吸收 碳储量 县域 西北干旱区 生态修复 国土空间规划
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南水北调中线总干渠藻类的生态调度 被引量:4
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作者 崔巍 刘哲 +1 位作者 穆祥鹏 陈文学 《南水北调与水利科技(中英文)》 CAS 北大核心 2022年第1期79-86,共8页
南水北调中线总干渠无在线调蓄水库,对藻类生态调度过程中出现的问题开展生态调度实现策略和实施方式研究。主要实现策略包括:划定自身的调蓄区,隔离生态调度对下游的影响;采用高效的渠池运行方式,减少生态调度时蓄量的反复调整;综合考... 南水北调中线总干渠无在线调蓄水库,对藻类生态调度过程中出现的问题开展生态调度实现策略和实施方式研究。主要实现策略包括:划定自身的调蓄区,隔离生态调度对下游的影响;采用高效的渠池运行方式,减少生态调度时蓄量的反复调整;综合考虑安全、快速、平稳等需求,设定生态调度实施进程和方式。具体实施方式包括:将总干渠划分为流速调控区、调蓄区和正常运行区,分别实施等体积、控制蓄量和闸前常水位方式运行;将生态调度过程划分为充水阶段和泄水阶段,基于流速调控目标值、持续时长和水位降幅约束条件,确定各阶段时长和各分区的闸门群调控方案等。基于2018年3月输水工况,采用明渠一维非恒定流模型,仿真总干渠上游15个渠池的藻类生态调度过程。结果表明,生态调度可在3.5 d内完成,各渠池的平均流速由0.48 m/s增至0.93 m/s,持续时间超过2 h。在整个生态调度过程中,水位变化平稳,水位变幅符合安全阈值要求,下游渠道的正常运行未受生态调度明显影响。 展开更多
关键词 南水北调中线工程 藻类生态调度 调蓄区 流速调控区 闸门群控制方法
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THE SIMULATED STORAGE CAPACITY OF FLOOD AND WATERLOGGING IN THE TYPICAL AGRICULTURAL REGION IN JIANGHAN PLAIN 被引量:4
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作者 WANG Xue-lei 1,2 ,LIU Xing-tu 2 ,HU Wang-bing 1 (1.Institute of Geodesy and Geophysics,the Chinese Academy of Sciences,Wuhan 430077,P.R.China 2.Changchun Institute of Geography,the Chinese Academy of Sciences,Changchun 130021,P.R.China) 《Chinese Geographical Science》 SCIE CSCD 2001年第3期68-72,共5页
The Jianghan plain is one of the important bases of China’s agricultural productivity,located in central and southern Hubei province in the mi ddle reach of Yangtze River.The Jian ghan Plain is the one region of floo... The Jianghan plain is one of the important bases of China’s agricultural productivity,located in central and southern Hubei province in the mi ddle reach of Yangtze River.The Jian ghan Plain is the one region of flood a nd waterlog-ging occurring frequently.The area is low-lying and is characterized by deep alluvial deposits,many smalle r rivers and numerous larger and shallow lakes fo rmed by meandering of the Changjiang(Yangtze)River.The alluvial plain is a honey-comb of waterways bordered by natura l levees,and the depressional areas encompassed by these waterways are dish-shaped in cross-section.The s ystems of rivers and lakes are main we tland types in this area.Owing to wetlands in Jianghan plain-lake district fulfill the function related to the flood r egulation,the estimating of the sto rage capacity is use-ful to controlling and reducing the d isasters of flooding and waterlogging.In this paper,by selecting typic al experimental area,based on its DEM,the relation a mong the water level,area and volume of inundation in the typical region i s de-fined by using regression analysis.Based on the agricultural cultivating line in this region and the experim ent result of bear-ing the inundation for crop,we defin e the storage capacity of the typical region in Jianghan Plain -Lake distr ict. 展开更多
关键词 Jianghan PLAIN storage capacity simulation AGRICULTURAL region
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利用自然冷源的蔬菜贮藏装置设计与适用区域 被引量:4
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作者 王喆 臧润清 +1 位作者 张秋玉 王欢 《中国果菜》 2017年第4期9-12,共4页
在我国的华北、东北和西北地区春冬季气温较低且持续时间长,有着很大的自然冷源蕴藏量,可以用于蔬菜的贮藏。本文介绍了利用自然冷源贮藏蔬菜的装置及其适用区域,主要包括适用于家庭的小型蔬菜贮藏装置和与冷库结合使用的大型蔬菜贮藏... 在我国的华北、东北和西北地区春冬季气温较低且持续时间长,有着很大的自然冷源蕴藏量,可以用于蔬菜的贮藏。本文介绍了利用自然冷源贮藏蔬菜的装置及其适用区域,主要包括适用于家庭的小型蔬菜贮藏装置和与冷库结合使用的大型蔬菜贮藏装置。分析表明:小型蔬菜贮藏装置通风效果好,利用室外冷源或室内热源,节约能源,提高蔬菜贮藏品质;大型蔬菜贮藏装置与冷库结合使用,在我国东北、西北地区气温较低、冬季较长的区域,可利用室外空气循环降温的时段较长,节能与环保效果显著。 展开更多
关键词 自然冷源 蔬菜贮藏 装置设计 适用区域 优点
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Grid Side Distributed Energy Storage Cloud Group End Region Hierarchical Time-Sharing Configuration Algorithm Based onMulti-Scale and Multi Feature Convolution Neural Network
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作者 Wen Long Bin Zhu +3 位作者 Huaizheng Li Yan Zhu Zhiqiang Chen Gang Cheng 《Energy Engineering》 EI 2023年第5期1253-1269,共17页
There is instability in the distributed energy storage cloud group end region on the power grid side.In order to avoid large-scale fluctuating charging and discharging in the power grid environment and make the capaci... There is instability in the distributed energy storage cloud group end region on the power grid side.In order to avoid large-scale fluctuating charging and discharging in the power grid environment and make the capacitor components showa continuous and stable charging and discharging state,a hierarchical time-sharing configuration algorithm of distributed energy storage cloud group end region on the power grid side based on multi-scale and multi feature convolution neural network is proposed.Firstly,a voltage stability analysis model based onmulti-scale and multi feature convolution neural network is constructed,and the multi-scale and multi feature convolution neural network is optimized based on Self-OrganizingMaps(SOM)algorithm to analyze the voltage stability of the cloud group end region of distributed energy storage on the grid side under the framework of credibility.According to the optimal scheduling objectives and network size,the distributed robust optimal configuration control model is solved under the framework of coordinated optimal scheduling at multiple time scales;Finally,the time series characteristics of regional power grid load and distributed generation are analyzed.According to the regional hierarchical time-sharing configuration model of“cloud”,“group”and“end”layer,the grid side distributed energy storage cloud group end regional hierarchical time-sharing configuration algorithm is realized.The experimental results show that after applying this algorithm,the best grid side distributed energy storage configuration scheme can be determined,and the stability of grid side distributed energy storage cloud group end region layered timesharing configuration can be improved. 展开更多
关键词 Multiscale and multi feature convolution neural network distributed energy storage at grid side cloud group end region layered time-sharing configuration algorithm
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农林交错地区森林碳储量估算——以中牟县为例 被引量:4
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作者 黄新峰 孙红召 +2 位作者 王巧玲 冯东阳 郑旭东 《中南林业调查规划》 2017年第2期55-58,共4页
为了估算中牟县森林碳储量,使用IPCC方法,采用经修正的生物量转换参数,区分片林和林带计算碳储量。结果表明:中牟县森林地上部分碳储量为32.62万t;而采用不加修正的参数估算林带碳储量时,森林总碳储量为31.60万t,造成1.02万t的差异,占... 为了估算中牟县森林碳储量,使用IPCC方法,采用经修正的生物量转换参数,区分片林和林带计算碳储量。结果表明:中牟县森林地上部分碳储量为32.62万t;而采用不加修正的参数估算林带碳储量时,森林总碳储量为31.60万t,造成1.02万t的差异,占森林总碳储量的3.1%,因此,区分片林和林带来计算农林交错区森林的碳储量是有必要的。 展开更多
关键词 碳储量 片林 林带 IPCC 农林交错地区 中牟县
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哈密地区冰川变化趋势分析 被引量:3
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作者 谢伟 姜逢清 《干旱区研究》 CSCD 北大核心 2014年第1期27-31,共5页
雪冰融水是哈密地区地表径流的一种主要方式。受全球气候变暖的影响,哈密地区的冰川处于加速融化的阶段,水资源成为哈密地区发展的主要瓶颈。通过对哈密地区冰川物质平衡、面积、厚度、冰川区水文气象等参数的观测,预测冰川水文和水资... 雪冰融水是哈密地区地表径流的一种主要方式。受全球气候变暖的影响,哈密地区的冰川处于加速融化的阶段,水资源成为哈密地区发展的主要瓶颈。通过对哈密地区冰川物质平衡、面积、厚度、冰川区水文气象等参数的观测,预测冰川水文和水资源的变化,为更好地利用好哈密地区有限的水资源,为可持续发展,提出应对措施。 展开更多
关键词 冰川 物质平衡 末端变化 雪冰融水 冰储量 哈密 新疆
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漳州地区仓储物害虫及其天敌调查初报 被引量:2
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作者 张清源 阮丽玉 +5 位作者 徐维斌 刘顺国 康玉珠 陈毅伟 余建明 张东斌 《华东昆虫学报》 2001年第1期23-29,共7页
1997年5月-1998年11月用近两年时间对漳州地区仓储物害虫和益虫开展调查。共采集标本1140份,经鉴定有仓储物害虫71种(隶属6目31科)益虫11种(隶属7目9科)。
关键词 仓储物害虫 天敌 名录 漳州地区 福建 益虫
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Analysis of terrestrial water storage changes in the Shaan-Gan-Ning Region using GPS and GRACE/GFO 被引量:2
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作者 Xianpao Li Bo Zhong +1 位作者 Jiancheng Li Renli Liu 《Geodesy and Geodynamics》 CSCD 2022年第2期179-188,共10页
Both the Global Positioning System(GPS)and Gravity Recovery and Climate Experiment(GRACE)/GRACE Follow-On(GFO)provide effective tools to infer surface mass changes.In this paper,we combined GPS,GRACE/GFO spherical har... Both the Global Positioning System(GPS)and Gravity Recovery and Climate Experiment(GRACE)/GRACE Follow-On(GFO)provide effective tools to infer surface mass changes.In this paper,we combined GPS,GRACE/GFO spherical harmonic(SH)solutions and GRACE/GFO mascon solutions to analyze the total surface mass changes and terrestrial water storage(TWS)changes in the Shaan-Gan-Ning Region(SGNR)over the period from December 2010 to February 2021.To improve the reliability of GPS inversion results,an improved regularization Laplace matrix and monthly optimal regularization parameter estimation strategy were employed to solve the ill-posed problem.The results show that the improved Laplace matrix can suppress the edge effects better than that of the traditional Laplace matrix,and the corre-lation coefficient and standard deviation(STD)between the original signal and inversion results from the traditional and improved Laplace matrix are 0.84 and 0.88,and 17.49 mm and 15.16 mm,respectively.The spatial distributions of annual amplitudes and time series changes for total surface mass changes derived from GPS agree well with GRACE/GFO SH solutions and mascon solutions,and the correlation coefficients of total surface mass change time series between GPS and GRACE/GFO SH solutions,GPS and GRACE/GFO mascon solutions are 0.80 and 0.77.However,the obvious differences still exist in local regions.In addition,the seasonal characteristics,increasing and decreasing rate of TWS change time series derived from GPS,GRACE/GFO SH and mascon solutions agree well with the Global Land Data Assimilation System(GLDAS)hydrological model in the studied area,and generally consistent with the precipitation data.Meanwhile,TWS changes derived from GPS and GRACE mascon solutions in the SGNR are more reliable than those of GRACE SH solutions over the period from January 2016 to June 2017(the final operation phase of the GRACE mission). 展开更多
关键词 Terrestrial water storage Shaan-Gan-Ning region GPS vertical displacements GRACE/GFO Improved Laplace matrix
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Evapotranspiration and soil water relationships in a range of disturbed and undisturbed ecosystems in the semi-arid Inner Mongolia,China 被引量:2
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作者 Nan Lu Shiping Chen +2 位作者 Burkhard Wilske Ge Sun Jiquan Chen 《Journal of Plant Ecology》 SCIE 2011年第1期49-60,共12页
Aims Evapotranspiration(ET)is a key component of water balance and is closely linked to ecosystem productivity.In arid regions,large proportion of precipitation(PPT)is returned to the atmosphere through ET,with only a... Aims Evapotranspiration(ET)is a key component of water balance and is closely linked to ecosystem productivity.In arid regions,large proportion of precipitation(PPT)is returned to the atmosphere through ET,with only a small amount available to plants.Our objective was to examine the variability in ET–soil water relationship based on a set of ecosystems that are representative for semi-arid Inner Mongolia and its main land use practices.Methods This study used Eddy covariance(EC)data of water vapor(i.e.ET,mm),PPT(mm),soil volumetric water content(VWC,%),root biomass density and soil properties from three paired sites in semi-arid Inner Mongolia:cropland(Cropland-D)versus undisturbed grassland(Steppe-D),grazed grassland(Grazed Steppe-X)versus fenced grassland(Fenced Steppe-X)and poplar plantation(Poplar-K)versus undisturbed shrubland(Shrubland-K).The paired sites experienced similar climate conditions and were equipped with the same monitoring systems.Important Findings The ET/PPT ratio was significantly lower at Cropland-D and Grazed Steppe-X in comparison to the undisturbed grasslands,Steppe-D and Fenced Steppe-X.These differences are in part explained by the lower VWC in the upper soil layers associated with compaction of surface soil in heavily grazed and fallow fields.In contrast,the ET/PPT ratio was much higher at the poplar plantation compared to the undisturbed shrubland because poplar roots tap groundwater.The VWC of different soil layers responded differently to rainfall events across the six study sites.Except for Poplar-K,ETwas significantly constrained by VWC at the other five sites,although the correlation coefficients varied among soil layers.The relative contribution of soil water to ET correlated with the density of root biomass in the soil(R2=0.67,P<0.01).The soil water storage in the upper 50 cm of soil contributed 59,43,64 and 23%of total water loss as ET at Steppe-D,Cropland-D,Shrubland-K and Poplar-K,respectively.Our across-site analysis indicates that the site level of soil water for ET dif 展开更多
关键词 EVAPOTRANSPIRATION soil water storage land use Inner Mongolia semi-arid region eddy-flux measurements
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太阳能斯特林混凝土储热系统传热特性研究 被引量:1
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作者 张欣宇 杨晓宏 +3 位作者 曹泽宇 张燕楠 田瑞 张爽 《太阳能学报》 EI CAS CSCD 北大核心 2022年第5期213-219,共7页
设计碟式太阳能斯特林机混凝土储热系统,并对熔融盐及混凝土传热过程进行理论分析,对混凝土储释热过程进行模拟,运用多目标遗传算法进行优化,得到以下结论:在释热过程,选取290℃为流体出口的有效温度临界值,有效释热时间约2.1 h时,流体... 设计碟式太阳能斯特林机混凝土储热系统,并对熔融盐及混凝土传热过程进行理论分析,对混凝土储释热过程进行模拟,运用多目标遗传算法进行优化,得到以下结论:在释热过程,选取290℃为流体出口的有效温度临界值,有效释热时间约2.1 h时,流体出口温度约为563 K,释热效率约为71%;高温混凝土和熔融盐沿着流程方向均存在一个温跃层区域,随着时间的延长,温跃层沿着流程方向逐渐向下游偏移,当温跃层移动到出口处时,熔融盐出口温度开始下降,温跃层占据的长度越小,储热系统效率越高;随着导热系数的增加,释热效率及有效释热时间提高。通过TOPSIS对解集进行重新排序分析,最优工况是蓄热量为2885 MJ、换热系数为672 W/(m·K)及储热效率为87%。 展开更多
关键词 碟式太阳能聚光系统 斯特林机 混凝土 储释热 储热 温跃层
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Capacity of Write-unidirectional Memory in Variable Rate Code Case
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作者 符方伟 《Chinese Science Bulletin》 SCIE EI CAS 1994年第1期1-4,共4页
A write-unidirectional memory (WUM)is a binary reusable information storagemedium. During the odd (or even) cycle of updating information, we can only write l’s(or 0’s) in selected bit positions of WUM, and not chan... A write-unidirectional memory (WUM)is a binary reusable information storagemedium. During the odd (or even) cycle of updating information, we can only write l’s(or 0’s) in selected bit positions of WUM, and not change other positions. WUM isa mathernatical model of a class of reusable digital discs. The writing constraints aredue to the storage technology of this class of reusable digital discs. During the storingand updating process, the storage speed of writing both 0’s and l’s is much 展开更多
关键词 WRITE -unidirectional MEMORY capacity region storage capacity.
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冰蓄冷技术在西安地区应用的经济分析
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作者 隋学敏 郑爱平 官燕玲 《长安大学学报(建筑与环境科学版)》 2004年第4期71-74,共4页
目前 ,中国的电力供应紧张 ,夏季用电峰谷差加大。冰蓄冷技术就是中国今后进行电力负荷的“移峰填谷”和需求侧管理 ( DSM) ,改善电力供需矛盾的一个最主要的技术措施。分析了冰蓄冷空调的特点及其工作原理 ,详细阐述了冰蓄冷空调系统... 目前 ,中国的电力供应紧张 ,夏季用电峰谷差加大。冰蓄冷技术就是中国今后进行电力负荷的“移峰填谷”和需求侧管理 ( DSM) ,改善电力供需矛盾的一个最主要的技术措施。分析了冰蓄冷空调的特点及其工作原理 ,详细阐述了冰蓄冷空调系统的“移峰填谷”运行策略——全部蓄冷和部分蓄冷 ,以及他们的调峰特点。以西安咸阳国际机场货运中心为例 ,对其冰蓄冷空调系统运行的经济性做了分析 ,说明了在西安地区采用冰蓄冷技术 ,可以节省大量运行费用 ,具有广阔的发展前景。 展开更多
关键词 经济分析 冰蓄冷技术 西安市 电力负荷 乙二醇溶液 资源配置
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Spatiotemporal changes in terrestrial water storage in the Beijing-Tianjin Sandstorm Source Region from GRACE satellites 被引量:1
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作者 Yingjun Pang Bo Wu +1 位作者 Yanping Cao Xiaohong Jia 《International Soil and Water Conservation Research》 SCIE CSCD 2020年第3期295-307,共13页
The Sandstorm Source Control Project in and around the Beijing-Tianjin region was one of the most important ecological projects in China.Terrestrial water storage(TWS)has important impacts on the ecological constructi... The Sandstorm Source Control Project in and around the Beijing-Tianjin region was one of the most important ecological projects in China.Terrestrial water storage(TWS)has important impacts on the ecological construction,agriculture,industry,and resident's lives.Based on the Gravity Recovery and Climate Experiment(GRACE)data,meteorological and Moderate Resolution Imaging Spectroradiometer(MODIS)data,etc.,this paper analyzed spatiotemporal characteristics of TWS,groundwater storage,and precipitation,and explored the influencing factors of regional TWS combined with land use and land cover(LULC),social and economic data.The most important results were as follows:(1)From 2003 to 2016,TWS in the Beijing-Tianjin Sandstorm Source Region showed a decreasing trend with a rate of 3.14 mm yr-1.(2)The TWS decline was caused mainly by groundwater overexploitation,but not pre-cipitation variation.(3)Spatiotemporal variations of TWS were related to LULC.The area with the most serious decrease of TWS was mainly located in the southwestern part of the region,where farmland percentage and population density were greater.(4)Reducing the percent of farmland and tree planting,and adding the shrub and grass planting,could be a viable choice for the Beijing-Tianjin Sandstorm Source Control Project.These results provide a scientific basis for regional water resource and ecological management. 展开更多
关键词 Terrestrial water storage Beijing-Tianjin Sandstorm Source region Groundwater LULC
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单链扫描可测性设计中存储元件的排序 被引量:1
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作者 叶波 郑增钰 《计算机学报》 EI CSCD 北大核心 1995年第8期598-603,共6页
本文提出了扫描设计中存储元件在扫描链中的最优排序方法.采用文迭测试体制和区间法能快速求出最优解.对于确定的测试向量集,用该方法构造的扫描链能使电路总的测试时间最少.
关键词 扫描设计 存储元件 时序电路 测试
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