检索结果-南通市图书馆

RE-AERATION LAW OF WATER FLOW OVER SPILLWAYS

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2006年第2期18卷 231-236页

作者： CHENG Xiang-ju LUO Lin CHEN Yong-can zhao wen-qian Department of Hydraulic Engineering Tsinghua University Beijing 100084 China State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China Departmentof Hydraulic Engineering Tsinghua University Beijing 100084 China

In order to explore the re-aeration law of water flow over spillway, the transfer process of oxygen in water flow over spillway was studied. The interfacial mass transfer coefficients were obtained by experiments. The flow fields and the turbulence characteristics are simulated by numerical methods. The fractional Volume Of Fluid （VOF） model of the air-water two phase flows was introduced to track the interface. Consequently, the quantitative expression of the interfacial mass transfer coefficients related with velocity and kinetic energy at the free surface was derived and the re-aeration model for the water flow over spillway was established. The examination with the experimental data of different conditions shows the validity of the re-aeration model for the water flow over spillways. This study will be important to evaluate the dissolved oxygen concentration and self-purification ability of rivers.

关键词： re-aeration mass transfer coefficient spillway

DISTRIBUTIONS OF FLOW RATE AND CONTAMINANT IN RIVER OR CHANNEL DIVERSION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1993年第2期5卷 69-75页

作者： Li, Ke-feng Luo, Lin Li, Jia zhao, wen-qian Chengdu Univ of Science & Technology Chengdu China

Based on numerical modelling for two-dimensional flow in which the density of effluent is different from that of environment, the flow and concentration fields are couplingly solved. Through numerical integration the flow rate and contaminant distributions with different angles and different momentum of effluent can be obtained. The results given in this paper could be a base for quantitative estimation in hydraulic engineering design and assessment and planning of water quality.

关键词： Channel flow Computational methods Effluents Flow of water Hydrodynamics Mathematical models Water pollution Water quality

THE TURBULENT MODEL OF LIQUID-PARTICLE FLOWS AND ITS APPLICATION TO NUMERICAL PREDICTION OF OIL POLLUTION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 1992年第2期4卷 72-78页

作者： Shen Yong-ming zhao wen-qian, Dalian University of Technology, Dalian 116023, P. R. China Dalian Univ of Technology Dalian China

Simulation of particle turbulent transport in present mathematical models of two- phase turbulent flows is algebraic model based on local following theory. The predicted results by these models are not consistent with that of experiments available. The motion of two-phase flow is described by a unified model of multi-fluid in this paper. The two-fluid turbulent model of two-phase flow based on k-e equations for particles and fluid, and corresponding numerical thch- nique are both developed. The proposed model and the numerical technique are successfully em- ployed to numerical modelling for oil-water two-phase turbulent recirculating flow.

关键词： liquid-particle flows particle turbulence oil pollution

在线全文

学校读者我要写书评

暂无评论

人在社交网络中的投资行为研究

电子科技大学学报 2018年第2期47卷 298-302页

作者：赵倩文吴晔王胜烽北京邮电大学理学院北京海淀区100876

以二元关系为基础的社交网络对于理解人的社会性非常重要,人们在社交关系上的投资模式很大程度上决定了社交网络的稳定性,而通讯是反映人与人之间情感交流的典型行为之一。本文通过中国某地区的通讯数据研究人们在构建和维系社会关系中... 详细信息

以二元关系为基础的社交网络对于理解人的社会性非常重要,人们在社交关系上的投资模式很大程度上决定了社交网络的稳定性,而通讯是反映人与人之间情感交流的典型行为之一。本文通过中国某地区的通讯数据研究人们在构建和维系社会关系中的资源投入和分配行为,提出了一个基于熵的衡量人们资源分配均匀性的指标。并利用该指标对不同年龄、性别的手机用户进行通话行为分析,发现男性、女性处于不同的年龄阶段时,在社交网络中资源的投入和分配有着明显的差异。

关键词：熵资源分配性别差异社交网络

Wave effect of gravitational waves intersected with a microlens field Ⅱ:An adaptive hierarchical tree algorithm and population study

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 241-254页

作者： Xikai Shan Guoliang Li Xuechun Chen wen zhao Bin Hu Shude Mao Department of Astronomy Tsinghua University Purple Mountain Observatory Chinese Academy of Sciences Institute for Frontier in Astronomy and Astrophysics Beijing Normal University School of Physics and Astronomy Beijing Normal University School of Astronomy and Space Science University of Science and Technology of China CAS Key Laboratory for Researches in Galaxies and Cosmology Department of Astronomy University of Science and Technology of ChinaChinese Academy of Sciences

The gravitational lensing wave effect generated by a microlensing field embedded in a lens galaxy is an inevitable phenomenon in strong lensed gravitational waves （SLGWs）.This effect presents both challenges and opportunities for the detection and application of ***,investigating this wave effect requires computing a complete diffraction integral over each microlens in the *** is extremely time-consuming due to the large number of microlenses （10～3-10～6）.Therefore,simply adding all the microlenses is ***,the complexity of the time delay surface makes the lens plane resolution a crucial factor in controlling numerical *** this paper,we propose a trapezoid approximation-based adaptive hierarchical tree algorithm to meet the challenges of calculation speed and *** find that this algorithm accelerates the calculation by four orders of magnitude compared to the simple adding method and is one order of magnitude faster than the fixed hierarchical tree algorithm proposed for electromagnetic *** importantly,our algorithm ensures controllable numerical errors,increasing confidence in the *** with our previous work （***.66,239511,2023）,this paper addresses all numerical issues,including integral convergence,precision,and computational time1).Finally,we conducted a population study on the microlensing wave effect of SLGWs using this algorithm and found that the microlensing wave effect cannot be ignored,especially for Type II SLGWs （from saddle position of the time delay surface） due to their intrinsic geometric structures and their typical intersection with a denser microlensing ***,more than 33%（11%） of SLGWs have a mismatch larger than 1%（3%） compared to the unlensed ***,we found that the mismatch between signal pairs in a doubly imaged GW is generally larger than 10-3,and 61%（25%） of signal pairs have a mismatch larger than 1%（3%）.Therefo

关键词： gravitational lensing diffractional integral algorithm gravitational wave

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

多层螺旋CT气道三维重建评价OSAS

中国医学影像学杂志 2009年第1期17卷 49-51页

作者：赵文前张晶解放军总医院放射诊断科北京100853

目的:探讨多层螺旋CT气道三维重建评价阻塞性睡眠呼吸暂停综合征(OSAS)。材料和方法:对33例OSAS患者及66例正常人行多层螺旋CT气道三维重建,测量上气道的矢状径、冠状径及截面积。对比OSAS患者与正常人各径线的差异。结果:OSAS患者上气... 详细信息

目的:探讨多层螺旋CT气道三维重建评价阻塞性睡眠呼吸暂停综合征(OSAS)。材料和方法:对33例OSAS患者及66例正常人行多层螺旋CT气道三维重建,测量上气道的矢状径、冠状径及截面积。对比OSAS患者与正常人各径线的差异。结果:OSAS患者上气道最狭窄处最多见于软腭后区,矢状径、冠状径和截面积分别为8.96mm、16.64mm和164.62mm2;其次是悬雍垂区。与对照组相比,软颚后区及悬壅垂区的矢状径、冠状径及截面积明显较对照组小,且差异有统计学意义。结论:多层螺旋CT气道三维重建能够对气道进行精确测量,并对狭窄部位和范围进行定位,为选择治疗方案包括外科手术方式提供可靠依据。

关键词：螺旋CT 气道三维重建阻塞性睡眠呼吸暂停综合征

在线全文

学校读者我要写书评

暂无评论

生物炭对大白菜幼苗生长的影响

农业环境科学学报 2015年第12期34卷 2394-2401页

作者：赵倩雯孟军陈温福沈阳农业大学辽宁省生物炭工程技术研究中心沈阳110866

以2个大白菜品种为试材,在常规育苗基质中添加不同比例的花生壳生物炭或玉米秸秆生物炭,研究生物炭对大白菜幼苗生长的影响。试验结果表明,生物炭添加有助于提升基质的通气性,与常规育苗基质相比增幅为2.1%~42.1%,显著提升了C/N和速效... 详细信息

以2个大白菜品种为试材,在常规育苗基质中添加不同比例的花生壳生物炭或玉米秸秆生物炭,研究生物炭对大白菜幼苗生长的影响。试验结果表明,生物炭添加有助于提升基质的通气性,与常规育苗基质相比增幅为2.1%~42.1%,显著提升了C/N和速效钾含量,增幅分别为23.9%~131.2%和48.8%~297.2%,同时,生物炭添加降低了基质碱解氮与有效磷含量,降幅分别为10.4%~44.8%和7.1%~20.8%,基质毛管孔隙度降幅为14.0%~19.6%。在花生壳生物炭与常规育苗基质等体积比混合处理中,大白菜幼苗株高、茎粗、叶绿素含量、植株鲜干重及壮苗指数等最高,长势最佳,但出苗率最低。

关键词：生物炭育苗基质大白菜

Effects of aggregate size distribution and carbon nanotubes on the mechanical properties of cemented gangue backfill samples under true triaxial compression

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 311-324页

作者： qian Yin Fan wen Zhigang Tao Hai Pu Tianci Deng Yaoyao Meng Qingbin Meng Hongwen Jing Bo Meng Jiangyu Wu State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China State Key Laboratory for Geomechanics&Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China Key Laboratory of Xinjiang Coal Resources Green Mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China

The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious ***,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of *** mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically *** results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,***,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the ***σ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite ***ε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse *** increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.

关键词： cemented gangue backfill materials particle size distribution true triaxial compression test carbon nanotubes mechanical properties failure modes

Direct and rapid detection of serum amino acid and monoamine neurotransmitters to assist the diagnosis of panic disorder

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第1期68卷 377-384页

作者： Shiwen Liu Xuerui Wan Meng zhao Jiaqi Wang Weilan Wu Linlin You Yonggui Yuan qian Xu Rong Gao Key Laboratory of Environmental Medicine Engineering Ministry of Education School of Public Health Southeast University Key Laboratory of Modern Toxicology of Ministry of Education Department of Hygienic Analysis and Detection School of Public HealthNanjing Medical University Department of Psychosomatics and Psychiatry Zhongda Hospital School of Medicine Southeast University

The measurement of amino acid and monoamine neurotransmitters（NTs） in serum plays a central role in the identification and monitoring of clinical panic disorder（PD）. However, the strong polarity and chemical heterogeneity of NTs make direct extraction and rapid detection extremely challenging. Herein, we developed a strategy that integrated solid phase extraction based on magnetic Fe3O4coated with polydopamine（Fe3O4@PDA） and direct analysis of mass spectrometry in real time（DART-MS） for quantification of 10 NTs. We systematically investigated the optimal conditions of this strategy to achieve good accuracy and precision. Compared with existing magnetic solid phase extraction methods for NTs detection in biological samples, this strategy could adsorb more targets while having similar adsorption efficiencies, and the total process time was reduced by an average of 69.42%. We rapidly determined the metabolic abnormality of 6 types of NTs in the serum of PD patients and demonstrated their diagnostic accuracy. In addition, an outstanding feature of PD in which tryptophan was more metabolized by the KYN pathway and the 5-hydroxytryptamine pathway was inhibited could be elucidated by this strategy. Our results highlighted the potential ability of Fe3O4@PDA coupled with DART-MS to assist in the clinical diagnosis of PD.

关键词： neurotransmitters panic disorder magnetic solid phase extraction direct analysis of mass spectrometry in real time