期刊文献+
共找到535篇文章
< 1 2 27 >
每页显示 20 50 100
Optimization and coordination of South-to-North Water Diversion supply chain with strategic customer behavior 被引量:4
1
作者 Zhi-song CHEN Hui-min WANG 《Water Science and Engineering》 EI CAS 2012年第4期464-477,共14页
The South-to-North Water Diversion (SNWD) Project is a significant engineering project meant to solve water shortage problems in North China. Faced with market operations management of the water diversion system, th... The South-to-North Water Diversion (SNWD) Project is a significant engineering project meant to solve water shortage problems in North China. Faced with market operations management of the water diversion system, this study defined the supply chain system for the SNWD Project, considering the actual project conditions, built a decentralized decision model and a centralized decision model with strategic customer behavior (SCB) using a floating pricing mechanism (FPM), and constructed a coordination mechanism via a revenue-sharing contract. The results suggest the following: (1) owing to water shortage supplements and the excess water sale policy provided by the FPM, the optimal ordering quantity of water resources is less than that without the FPM, and the optimal profits of the whole supply chain, supplier, and external distributor are higher than they would be without the FPM; (2) wholesale pricing and supplementary wholesale pricing with SCB are higher than those without SCB, and the optimal profits of the whole supply chain, supplier, and external distributor are higher than they would be without SCB; and (3) considering SCB and introducing the FPM help increase the optimal profits of the whole supply chain, supplier, and external distributor, and improve the efficiency of water resources usage. 展开更多
关键词 South-to-North water Diversion supply chain strategic customer behavior floatingpricing mechanism
下载PDF
Reliability model of organization management chain of South-to-North Water Diversion Project during construction period 被引量:3
2
作者 Feng Jingchun Zhou Yang +2 位作者 Hong Yuzhen Zhao Shixin Ren Xiaoqiang 《Water Science and Engineering》 EI CAS 2008年第4期107-113,共7页
In order to analyze the indispensability of the organization management chain of the South-to-North Water Diversion Project (SNWDP), two basic forms (series connection state and mixed state of both series connectio... In order to analyze the indispensability of the organization management chain of the South-to-North Water Diversion Project (SNWDP), two basic forms (series connection state and mixed state of both series connection and parallel connection) of the organization management chain can be abstracted. The indispensability of each form has been studied and is described in this paper. Through analysis of the reliability of the two basic forms, reliability models of the organization management chain in the series connection state and the mixed state of both series connection and parallel connection have been set up. 展开更多
关键词 South-to-North water Diversion Project reliability model management chain parallel connection series connection
下载PDF
Critical chain construction with multi-resource constraints based on portfolio technology in South-to-North Water Diversion Project 被引量:3
3
作者 Jing-chun FENG Lei LI +4 位作者 Nan YANG Yu-zhen HONG Min PANG Xiong YAO Li-cheng WANG 《Water Science and Engineering》 EI CAS 2011年第2期225-236,共12页
Recently, the critical chain study has become a hot issue in the project management research field. The construction of the critical chain with multi-resource constraints is a new research subject. According to the sy... Recently, the critical chain study has become a hot issue in the project management research field. The construction of the critical chain with multi-resource constraints is a new research subject. According to the system analysis theory and project portfolio theory, this paper discusses the creation of project portfolios based on the similarity principle and gives the definition of priority in multi-resource allocation based on quantitative analysis. A model with multi-resource constraints, which can be applied to the critical chain construction of the A-bid section in the South-to-North Water Diversion Project, was proposed. Contrast analysis with the comprehensive treatment construction method and aggressive treatment construction method was carried out. This paper also makes suggestions for further research directions and subjects, which will be useful in improving the theories in relevant research fields. 展开更多
关键词 multi-resource constraints South-to-North water Diversion Project project portfolio critical chain
下载PDF
Three-dimensional Motion of Multichain-Buoy Mooring System in shallow Water and Survival Conditions 被引量:1
4
作者 Zhang Ting Sun Mingguang Graduate student, Department of Applied Mechanics and Engineering, Zhongshan University,Guangzhou 510275Professor, Department of Applied Mechanics and Engineering, Zhongshan University, Guangzhou 510275 《China Ocean Engineering》 SCIE EI 1997年第3期261-272,共12页
An engineering numerical model for three dimensional motion of multichain-buoy mooring system in shallow water and survival condition is given in this paper. Shooting-aim method is employed for solving the dynamic equ... An engineering numerical model for three dimensional motion of multichain-buoy mooring system in shallow water and survival condition is given in this paper. Shooting-aim method is employed for solving the dynamic equations of chain system in order to match the computation of buoy motion. The responses of buoy and chain have been computed for different wind-wave-current directions and different rigidity of chain. The results show that the present numerical model is reasonable. 展开更多
关键词 survival condition shallow water chain system three-dimensional motion
下载PDF
Support Vector Machines(SVM)-Markov Chain Prediction Model of Mining Water Inflow 被引量:2
5
作者 Kai HUANG 《Agricultural Science & Technology》 CAS 2017年第8期1551-1554,1558,共5页
This study was conducted to establish a Support Vector Machines(SVM)-Markov Chain prediction model for prediction of mining water inflow. According to the raw data sequence, the Support Vector Machines(SVM) model was ... This study was conducted to establish a Support Vector Machines(SVM)-Markov Chain prediction model for prediction of mining water inflow. According to the raw data sequence, the Support Vector Machines(SVM) model was built, and then revised by means of a Markov state change probability matrix. Through dividing the state and analyzing absolute errors and relative errors and other indexes of the measured value and the fitted value of SVM, the prediction results were improved. Finally,the model was used to calculate relative errors. Through predicting and analyzing mining water inflow, the prediction results of the model were satisfactory. The results of this study enlarge the application scope of the Support Vector Machines(SVM) prediction model and provide a new method for scientific forecasting water inflow in coal mining. 展开更多
关键词 Mining water inflow Support Vector Machines (SVM) Markov chain
下载PDF
Analysis on the Structure of Influencing Factors of Sustainable Supply Chain Implementation of Water Diversion Project 被引量:3
6
作者 Meng Liu Liwei Yang Tongsheng Liu 《Journal of Geoscience and Environment Protection》 2021年第8期140-150,共11页
The systematic analysis of the hierarchical relationship among the factors affecting the sustainable supply chain implementation of water diversion projects has theoretical value and practical significance for the sus... The systematic analysis of the hierarchical relationship among the factors affecting the sustainable supply chain implementation of water diversion projects has theoretical value and practical significance for the sustainable development of large-scale water diversion projects. Through the investigation of relevant literature, books, web pages, materials, and discussions with relevant experts and scholars, a total of 23 factors influencing the sustainable supply chain implementation of water diversion projects were identified. Then using ISM (Interpretative Structural Modeling Method) to analyze the causality of each factor, a multi-level hierarchical structure model was obtained. The results showed that: 1) The surface-level influencing factors of the sustaina<span>ble supply chain implementation of the water diversion project mainly i</span>ncluded 8 factors such as water-saving awareness and water-saving intensity in the diversion area, water quality, water pollution and other disasters, effective incentive mechanisms, etc., and surface-level influencing factors were directly related to the sustainable supply chain implementation of water diversio<span>n projects. 2) The indirect influencing factors of the sustainable supply chai</span>n of water diversion projects included 12 factors such as the water quality and quantity guarantee rate of the supply chain, the government’s enforcement of laws and regulations, water distribution, ecological compensation, and compensatio<span>n mechanisms for residents in the water source area. Indirect influencing</span> factor scan acts directly on the direct influencing factors, and int<span>ervening in the factors that can be controlled by humans is one of the important ways to improve the sustainable operation of water diversion proj</span><span>e</span><span>cts. 3) T</span><span>he fundamental influencing factors for the sustainable supply chain implementation of water diversion projects included three f</span>actors: Resettlement policy, government financial support, and sound laws and regulations. Deep influencing factors had multi-channel influence and controllability, and intervening in them was the main means to improve the sustainable operation of water diversion projects. 展开更多
关键词 water Diversion Project Sustainable Supply chain Interpretative Structural Modelling Method Hierarchical Structure Model
下载PDF
Octa-membered Water Ring Chain Based on Sulfonic Group in Ni(II) Complex with 2-[(E)-(2-Oxidophenyl)methyleneamino] Ethanesulfonato and 2,2′-Bipyridinyl 被引量:2
7
作者 张淑华 李光照 +1 位作者 钟凡 冯小珍 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第12期1491-1494,共4页
The title compound, [Ni(tssb)(2,2-bipy)2].5(H2O) 1 (tssbH2 =2-[(E)-(2-oxido- phenyl)methyleneamino]ethanesulfonato, 2,2-bipy = 2,2'-bipyridinyl), belongs to orthorhombic, space group Pbcn with a = 20.3983... The title compound, [Ni(tssb)(2,2-bipy)2].5(H2O) 1 (tssbH2 =2-[(E)-(2-oxido- phenyl)methyleneamino]ethanesulfonato, 2,2-bipy = 2,2'-bipyridinyl), belongs to orthorhombic, space group Pbcn with a = 20.3983(18), b = 17.6929(15), c = 17.0897(15) nm, V= 6167.8(9) nm^3, Mr= 688.38, Z = 8, De = 1.481 g.cm^-3, F(000) = 2880,μ = 0.758 mm-1 and S =1.099. Each NiIr atom is six-coordinated by one N and one O atoms from one tssb^2- anion and four N atoms from two 2,2-bipy ligands to give a distorted octahedral geometry. Noticeably, there exists a rare octa-mem- bered water ring which presents a 1D chain by sulfonic group. 展开更多
关键词 II Octa-membered water Ring chain Based on Sulfonic Group in Ni Bipyridinyl Complex with 2 Ethanesulfonato and 2 2 Oxidophenyl)methyleneamino
下载PDF
Novel Waterborne Fluorinated Polyurethane Containing Fluoroalkyl Side Chain:Synthesis,Characterization and Application on Cotton Fabric 被引量:1
8
作者 黄燕平 孟卫东 《Journal of Donghua University(English Edition)》 EI CAS 2011年第1期35-39,共5页
A polyether diol poly[3-bromomethyl-3-tridecafluorooctyloxymethyloxetane]glycol(PFBOX 3) was prepared in 91% yield from ring opening polymerization of 3-bromomethyl-3-tridecafluorooctyloxymethyloxetane 2 which was der... A polyether diol poly[3-bromomethyl-3-tridecafluorooctyloxymethyloxetane]glycol(PFBOX 3) was prepared in 91% yield from ring opening polymerization of 3-bromomethyl-3-tridecafluorooctyloxymethyloxetane 2 which was derived from 3,3-dibromomethyloxetane 1 and 1H,1H,2H,2H-perfluorooctanol.The waterborne fluorinated polyurethane FPU was thus obtained by condensed polymerization of PFBOX 3 with isophoronediisocyanate(IPDI).The structure of FPU was characterized by Fourier transform infrared spectrometer(FTIR).FPU showed good thermal stability under 300℃.The surface properties of FPU were studied by applied on cotton fabric.The treated fabric surface showed excellent water repellent property as the contact angle reached 147°.On the other hand,the surface showed slightly oil repellent property as the contact angle for nujol droplet was 126°. 展开更多
关键词 waterborne polyurethane fluoroalkyl side chains water and oil repellency cotton fabrics
下载PDF
A 3D Supramolecular Framework Based on 1D {[Co(proH)(H_2O)_3]_2[P_2Mo_5O_(23)]}_n Chains and 1D Helical Water Chains
9
作者 吴小园 匡小飞 +1 位作者 余荣民 卢灿忠 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2009年第11期1513-1518,共6页
A three-dimensional supramolecular architecture, {[Co(proH)(H2O)3]2[P2Mo5O23]}·7H2O (1, pro = praline), has been synthesized and characterized by IR, elemental analysis, thermogravimetric analysis, and sing... A three-dimensional supramolecular architecture, {[Co(proH)(H2O)3]2[P2Mo5O23]}·7H2O (1, pro = praline), has been synthesized and characterized by IR, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. 1 crystallizes in monoclinic, space group C2 with a = 20.600(3), b = 11.6980(11), c = 9.2944(10)A, β = 107.837(4)°, V = 2132.1(4) A^3, Z = 2, C10H46Co2Mo5N2O40P2, Mr = 1493.99, Dc = 2.327 g/cm^3, F(000) = 1468, μ(MoKα) = 2.375 mm^-1, the final R = 0.0339 and wR = 0.0844 for 4169 observed reflections with I 〉 2σ(I). Singlecrystal X-ray crystallographic analysis reveals that the helical water chains and {[Co(proH)- (H2O)3]2[P2Mo5O23]}n chains are perpendicular to each other and extend into an overall three-dimensional supramolecular architecture by hydrogen-bonding interactions. The magnetic investigation indicates weak antiferromagnetic interactions in the compound. 展开更多
关键词 POLYOXOMETALATES diphosphopentamolybdate amino acid hefical water chain
下载PDF
Multisource Disaster Chain and Control in Regional Water Environment of the Dongjiang Lake in China
10
作者 Feng Gao Ronglan Xiao 《Journal of Water Resource and Protection》 2015年第15期1174-1182,共9页
On the background of analysis on region water environment safety in the Dongjiang Lake of south-central China, the source of pollution of water environment and its control are studied. The concept of region environmen... On the background of analysis on region water environment safety in the Dongjiang Lake of south-central China, the source of pollution of water environment and its control are studied. The concept of region environment disaster chain is put forward on the basis of combination study on the disaster chain theory and pollution problem in regional water environment. Through identification and analysis of pollution disaster resources in regional water environment of the Dongjiang Lake, the annual emission of the chemical oxygen demand (COD), ammonia nitrogen, total phosphorus (TP) and heavy metal (Cd, As, Pb) are counted. According to evaluation on structure proportion of contaminants in the Dongjiang Lake, agricultural non-point source is the uppermost pollution source, which accounted for 87.74% in total pollution load. Ammonia nitrogen, TP and COD are mainly contaminants accounted for 94.27% in total pollution load. By analyzing danger of contaminants in the lake, basic form of disaster chain of water environment pollution is built elementarily. It shows characteristics of branches and trunk basin disaster chain and embodies multisource disaster implication chain caused by human activities. Then, disaster resources chain-cutting methods for pollution prevention and control of regional water environment of the Dongjiang Lake are analyzed. 展开更多
关键词 Regional water Environment DISASTER chain chain-Cutting DISASTER Mitigation from GESTATION Source water POLLUTION Control The Dongjiang LAKE
下载PDF
Water Memory Due to Chains of Nano-Pearls
11
作者 Auguste Meessen 《Journal of Modern Physics》 2018年第14期2657-2724,共68页
Biologically active molecules create substitutes in liquid water by forming single-domain ferroelectric crystallites. These nanoparticles are spherical and constitute growing chains. The dipoles are aligned, but can b... Biologically active molecules create substitutes in liquid water by forming single-domain ferroelectric crystallites. These nanoparticles are spherical and constitute growing chains. The dipoles are aligned, but can be set in oscillation at the frequency of vibration of the charged part of active molecules. They are then automatically trimmed and become information carriers. Moreover, they produce an oscillating electric field, causing autocatalytic multiplication of identical chains in the course of successive dilutions. Active molecules are thus only required to initiate this process. Normally, they excite their specific receptors by resonance, but trimmed chains have the same effect. This theory is confirmed by many measurements. 展开更多
关键词 water MEMORY Extra-High Dilutions FERROELECTRIC Particles chainS of Nanoparticles water BRIDGES Molecular INTERACTIONS
下载PDF
鄂尔多斯红庆河采煤矿区生态需水研究
12
作者 姜庆宏 张靖雯 +2 位作者 郑春丽 王哲 龙文毫 《金属矿山》 CAS 北大核心 2024年第9期260-266,共7页
鄂尔多斯红庆河煤矿区处在西部干旱半干旱内陆区域,由于煤炭开采导致生态环境问题较为突出,该区域水资源短缺、供需失衡,严重制约了矿区的生态恢复。在充分的自然概况调查基础上,将红庆河煤矿区生态需水划分为天然生态需水和人工生态需... 鄂尔多斯红庆河煤矿区处在西部干旱半干旱内陆区域,由于煤炭开采导致生态环境问题较为突出,该区域水资源短缺、供需失衡,严重制约了矿区的生态恢复。在充分的自然概况调查基础上,将红庆河煤矿区生态需水划分为天然生态需水和人工生态需水2种类型。通过植被蒸散法对植被生态需水进行计算,使用马尔科夫链进行定性预测,利用灰色预测模型GM(1,1)进行定量预测。结果表明:以2020年为基准年,红庆河煤矿区总生态需水量为37.52×10^(7)m^(3),天然植被每平方千米乔木、灌木、草地生态需水量分别为1.11×10^(6)、1.06×10^(6)、0.36×10^(6)m^(3);人工生态需水量为1.39×10^(7)m^(3)。进一步对研究区生态需水进行定性、定量预测,规划年(2025年、2030年、2035年)矿区天然生态需水量相比基准年分别上升了0.61%、2.57%和4.57%;人工生态需水量分别上升了3.60%、11.51%和20.86%。研究结果可为该地区生态恢复中植被类型选择、水资源开发利用、合理调配水资源提供科学依据。 展开更多
关键词 生态需水 灰色预测模型 马尔科夫链 定量预测
下载PDF
微波处理对刺槐豆胶多糖结构特征的影响 被引量:2
13
作者 王帅 孔博洋 +5 位作者 李婷 贾小艳 肖红 位张坤 张继 王俊龙 《中国食品添加剂》 CAS 2024年第1期87-98,共12页
采用微波辅助法(microwave-assisted extraction,MAE)和热水浸提法(hot water extraction,HWE)处理刺槐豆胶,并对得到的刺槐豆胶多糖(locust bean gum polysaccharide,LBGP)进行分子量及分子量分布、糖链构象、单糖组成、糖苷键类型等... 采用微波辅助法(microwave-assisted extraction,MAE)和热水浸提法(hot water extraction,HWE)处理刺槐豆胶,并对得到的刺槐豆胶多糖(locust bean gum polysaccharide,LBGP)进行分子量及分子量分布、糖链构象、单糖组成、糖苷键类型等一系列表征进行分析。通过比较发现,MAE-LBGP的分子量(2.744〜3.777×10^(6) g/mol)显著高于HWE-LBGP(1.222〜1.593×10^(6) g/mol),且具有更宽的分子量分布,不均一性的增强使得糖链呈现出更加多样化及更为紧密的构象特征,而HWE-LBGP的构象则表现得相对单一和松散。经由两种提取方式得到的LBGP具有相同的单糖组成种类(甘露糖和半乳糖)和糖苷键类型(1→4与1→6位连接键)。以上结果归因于在微波效应的作用下,溶剂的极化作用增强,提取能力增加,并通过增强溶剂的传质能力,获得了高分子量和更宽分布的多糖所致。本研究为微波技术在多糖提取应用方面提供了支持和帮助。 展开更多
关键词 刺槐豆胶多糖 微波辅助提取 热水浸提 微波效应 糖链构象
下载PDF
短链含氟聚丙烯酸酯功能整理剂的制备及应用 被引量:1
14
作者 周克 郝海涛 +3 位作者 陈旭 朱文浩 于梦瑶 李永强 《浙江理工大学学报(自然科学版)》 2024年第1期74-81,共8页
为制备耐水洗性能优良的三防整理剂,以丙烯酸十三氟辛酯(Tridecooctyl acrylate,C6F)和丙烯酸十八酯(Octaglycidyl acrylate,SA)为主要单体,甲基丙烯酸缩水甘油酯(Glycidyl methacrylate,GMA)为交联单体,通过细乳液聚合法制备了一种短... 为制备耐水洗性能优良的三防整理剂,以丙烯酸十三氟辛酯(Tridecooctyl acrylate,C6F)和丙烯酸十八酯(Octaglycidyl acrylate,SA)为主要单体,甲基丙烯酸缩水甘油酯(Glycidyl methacrylate,GMA)为交联单体,通过细乳液聚合法制备了一种短链含氟丙烯酸酯共聚物细乳液,并将其作为整理剂应用在棉织物上;通过红外光谱分析、粒径分析和热重分析对乳液进行表征,采用场扫描电镜和X射线光电子能谱仪对棉织物表面结构进行分析,探究C6F和SA的用量对该共聚物薄膜表面能的影响。结果表明:当C6F质量分数为50%,SA质量分数为25%时,共聚物薄膜的表面能低至9.16mN/m;整理后棉织物的水接触角为150.8°,橄榄油接触角为141.2°,拒水等级4级,拒油等级4级,耐沾污等级5级;整理后棉织物经过20次水洗后水接触角仍有135.7°,橄榄油接触角为124.8°,表现出良好的耐水洗性能。该文可为制备短链C6型含氟丙烯酸酯共聚物提供数据参考。 展开更多
关键词 短链含氟丙烯酸酯 细乳液聚合 棉织物 三防性能 耐水洗性能
下载PDF
不同软段的长碳链聚酰胺弹性体的合成与性能
15
作者 赵千龙 周南 +6 位作者 张袁铖 赵蔚 张晓朦 崔喆 付鹏 庞新厂 刘民英 《工程塑料应用》 CAS CSCD 北大核心 2024年第5期29-34,49,共7页
为研究软段种类对聚酰胺(PA)弹性体性能的影响,合成了具有不同性能的热塑性PA弹性体(TPAE)。以十二碳二元酸、十二碳二元胺和三种不同种类的聚醚[聚环氧乙烷(PEO)、聚环氧丙烷(PPO)和聚四氢呋喃(PTHF)]为原料,采用一步法分别合成了三个... 为研究软段种类对聚酰胺(PA)弹性体性能的影响,合成了具有不同性能的热塑性PA弹性体(TPAE)。以十二碳二元酸、十二碳二元胺和三种不同种类的聚醚[聚环氧乙烷(PEO)、聚环氧丙烷(PPO)和聚四氢呋喃(PTHF)]为原料,采用一步法分别合成了三个系列的PA1212基热塑性弹性体。采用傅里叶变换红外光谱、核磁共振氢谱确定了TPAE的成功合成,通过差示扫描量热分析、热失重分析、动态力学分析(DMA)、力学性能测试、吸水性能测试和电阻率测试对TPAE的性能进行了表征。结果表明,合成的TPAE的熔点高于170℃,热分解温度高于410℃,其中PEO系列弹性体的熔点和结晶温度较高。DMA测试结果表明PEO软段与PA硬段相容性最好,而PPO系列弹性体在-50~-40℃之间的tanδ大于0.3,表明此种材料在低温下具有良好的阻尼性能。PEO系列弹性体力学性能最优,拉伸强度在30~38.5 MPa之间,断裂伸长率高于620%,且拥有较高的吸水性能,饱和吸水率可达到30.2%,体积电阻率相对于PA1212降低了6个数量级。而PTHF系列弹性体有着最低的吸水率,饱和吸水率低至1.4%。三种材料可以应用于不同场景。 展开更多
关键词 长碳链聚酰胺 热塑性弹性体 聚酰胺弹性体 阻尼性能 吸水性能
下载PDF
新疆农业水资源绿色效率时空演变及影响因素研究 被引量:1
16
作者 褚家琦 蒋志辉 《干旱区地理》 CSCD 北大核心 2024年第7期1231-1241,共11页
通过对农业面源污染、农业净碳汇等变量测算构建指标体系,采用超效率SBM模型、Malmquist指数模型方法计算2011—2020年新疆14个行政区农业水资源绿色效率值及其分解指数值,绘制标准差椭圆并构建马尔科夫链概率矩阵分析其空间格局变化,并... 通过对农业面源污染、农业净碳汇等变量测算构建指标体系,采用超效率SBM模型、Malmquist指数模型方法计算2011—2020年新疆14个行政区农业水资源绿色效率值及其分解指数值,绘制标准差椭圆并构建马尔科夫链概率矩阵分析其空间格局变化,并用Tobit模型分析其影响因素。结果表明:(1)新疆各地州研究期内农业水资源绿色效率均值为0.865;各地区农业水资源绿色效率水平、提升效果及速度存在明显差异。(2)研究期内重心坐标始终在巴音郭楞蒙古自治州和静县巴音布鲁克镇内移动,先向东北移动后西南最终又向东北方向折回;较低、较高、高效率类型地区之间具有相互转移或跨类型转移的概率,低效率地区难以快速或跨类型增长。(3)经济发展水平、农业经济、供水结构对农业水资源绿色效率有显著的正向影响,资源禀赋与节水设施对农业水资源效率有显著的负向影响。研究结果对新疆农业水资源可持续利用、建设绿色高效农业具有重要的现实意义。 展开更多
关键词 农业水资源绿色效率 超效率SBM模型 Malmquist指数模型 空间演变 马尔科夫链 TOBIT模型
下载PDF
核岛冷链通风空调系统性能优化研究
17
作者 伍经纬 郑文科 +1 位作者 王玉 姜益强 《暖通空调》 2024年第3期111-117,共7页
核岛冷链通风空调系统的设计存在余量值过大、运行能耗高、调节控制笨重等问题。为了降低核电的成本,本文基于“华龙一号”某厂房实际通风空调系统,建立了主要能耗设备的数学模型,确定了系统节能优化目标函数和约束条件,使用遗传算法研... 核岛冷链通风空调系统的设计存在余量值过大、运行能耗高、调节控制笨重等问题。为了降低核电的成本,本文基于“华龙一号”某厂房实际通风空调系统,建立了主要能耗设备的数学模型,确定了系统节能优化目标函数和约束条件,使用遗传算法研究了通风空调系统节能运行的优化效果。分别计算了2种优化方案在负荷率变化和高温与常温末端负荷比不同时,系统整体及各设备能耗情况。结果表明:单台冷水机组运行,高温与常温末端串联的系统形式节能率为14.1%,但随着末端负荷比的增大,节能率降低;单台冷水机组运行,高温与常温末端串联、高温末端额外增加高温冷水机组的系统形式在负荷比为2时节能率为17.2%,节能效果优于方案1的12.2%。 展开更多
关键词 核岛 冷链 冷水系统 遗传算法 节能 性能优化
下载PDF
多水塘活水链人工湿地浮游植物群落变化及影响因子--以十八联圩湿地为例
18
作者 耿显双 何云峰 +4 位作者 孙天一 李典鹏 傅海峰 冷欣 安树青 《湿地科学与管理》 2024年第4期44-49,共6页
十八联圩是巢湖的重要河口湿地。采用多水塘活水链工艺进行规划建设,以其中4个表流湿地单元为对象,2023年3月和7月调查其水质物化指标及浮游植物群落结构。结果表明:多水塘活水链湿地能够有效去除营养污染物,但冬季、夏季水质差异较大... 十八联圩是巢湖的重要河口湿地。采用多水塘活水链工艺进行规划建设,以其中4个表流湿地单元为对象,2023年3月和7月调查其水质物化指标及浮游植物群落结构。结果表明:多水塘活水链湿地能够有效去除营养污染物,但冬季、夏季水质差异较大。冬季和夏季分别鉴定出浮游植物8门127种和8门213种,夏季主要以蓝藻门浮游植物为优势物种,而冬季硅藻门优势种数量更多,伪鱼腥藻(Pseudoanabaena)在两个季节均为优势物种,其在食物网中可能处于关键位置。冬夏季浮游植物的主要环境影响因子存在差异,冬季氮元素和DO对浮游植物种群的影响最大,夏季COD、NO_(3)-N和TP对浮游植物种群的影响最大。浮游植物的长期监测能够为巢湖及周边流域生态健康恢复提供数据支撑和理论基础。 展开更多
关键词 十八联圩 多水塘活水链 浮游植物 人工湿地
下载PDF
论煤-水-土多资源协调开发
19
作者 王双明 孙强 +9 位作者 袁士豪 师庆民 侯恩科 陈凯 黄震 吴海波 武佳坤 耿济世 张玉良 黄金廷 《西北地质》 CAS CSCD 北大核心 2024年第5期1-10,共10页
煤炭及其伴生资源是地质体的重要组成部分,大规模和高强度开采会引起近地表岩石圈、土壤圈、水圈的联动响应,进而反向制约煤炭及其伴生资源的安全开采与开发。围绕煤矿区的煤-水-土多资源协调开发,基于多学科知识交叉的地球关键带理念,... 煤炭及其伴生资源是地质体的重要组成部分,大规模和高强度开采会引起近地表岩石圈、土壤圈、水圈的联动响应,进而反向制约煤炭及其伴生资源的安全开采与开发。围绕煤矿区的煤-水-土多资源协调开发,基于多学科知识交叉的地球关键带理念,阐述煤-水-土协调开发的必要性以及多圈层、多过程、多尺度、多目标的耦合关系,为煤炭安全绿色开发和生态环境可持续发展提供战略思考。(1)立足煤炭安全高效开采、土壤-水资源安全和生态环境保护多目标多维度角度,剖析大规模、高强度开发背景下采前、采中、采后地质条件动态演化、多资源时空关系、生态环境响应特征,提出煤炭资源开发生命周期条件下的煤炭资源区的地质调查战略和开发策略。(2)开展煤-水-土多资源量的系统调查和地质结构精细表征,全面理解和综合评价煤-水-土赋存特征和相互依存关系,形成集资源禀赋、生态环境、人口经济等于一体的地质调查评价体系和方法,提出基于煤炭开发、多资源利用、水土保护、生态屏障、土地安全等一体化的全链条调控措施和开发策略与开发政策。(3)监控开发过程中地层地质功能结构变化,理解煤-水-土空间组合结构及分层界面效应和煤(岩)-水-土相互作用的动态演化规律,构建复杂地层结构煤炭安全开采和水-土资源协调开发覆岩变形的演化模型,厘清煤-水-土空间结构及其对开采活动的约束效应,发展地球科学、采矿学、生态学、水文学等多学科交叉的煤炭绿色开发地质保障理论与技术。煤-水-土协调开发研究服务于煤炭安全开采与地质环境保护协调发展,破解多资源开发瓶颈及其地质环境制约之间矛盾,通过对煤炭开采全生命周期内的地质条件和环境效应的关键影响因素、状态参数阈值、演化驱动机制的理解,构建地质环境约束、开采模式调控、系统规划利用的煤-水-土多资源协调开发时空格局。 展开更多
关键词 煤-水-土协调开发 开采地质条件 多界面效应 动态耦合响应 时空演化规律 全链条综合开发
下载PDF
Orientations of special water dipoles that accelerate water molecules exiting from carbon nanotube
20
作者 亓文鹏 涂育松 +1 位作者 万荣正 方海平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第9期1101-1108,共8页
One-dimensional ordered water molecules entering and exiting from a carbon nanotube with an appropriate radius are studied with molecular dynamics simulations.It can be found that a water molecule near the nanotube en... One-dimensional ordered water molecules entering and exiting from a carbon nanotube with an appropriate radius are studied with molecular dynamics simulations.It can be found that a water molecule near the nanotube end is more likely to be expelled from the nanotube if its dipole is almost perpendicular to the nanotube axis.The key to this observation is that those water molecules are closer to the wall of the nanotube away from the equilibrium position of the Lennar-Jones (LJ) potential.Thus,the interaction energy for those water molecules is relatively high.There are two particular structures of the perpendicular water molecule depending on the dipole direction of the adjacent water molecule in the nanotube.Although the probabilities of these structures are quite small,their contributions to the net flux across the nanotube end are approximately equal to the predominant structures.The present findings further show the possibility of controlling the water flow by regulating the dipole directions of the water molecules inside the nanochannels. 展开更多
关键词 water carbon nanotube single-file water chain Lennard-Jones (LJ) interaction
下载PDF
上一页 1 2 27 下一页 到第
使用帮助 返回顶部