检索结果-南通市图书馆

Experimental and numerical modelling of sedimentation in a rectangular shallow basin

International Journal of sediment Research 2008年第3期23卷 212-232页

作者： sameh A. KANTOUsH Erik BOLLAERT Anton J. sCHLEIss Ecole Polytechnique Fédérale de Lausanne (EPFL) Laboratory of Hydraulic Constructions (LCH) Station 18 CH -1015 Lausanne SwitzerlandDr. Ecole Polytechnique Fédérale de Lausanne (EPFL) Laboratory of Hydraulic Constructions (LCH) Station 18 CH -1015 Lausanne SwitzerlandProf.

Numerical simulation of flows in shallow reservoirs has to be checked for its consistency in predicting real flow conditions and sedimentation patterns. Typical flow patterns may exhibit flow separation at the inlet, accompanied by several recirculation and stagnation areas all over the reservoir surface. The aim of the present research project is to study the influence of the geometry of a reservoir on sediment transport and deposition numerically and experimentally, focusing on a prototype reservoir depth between 5 and 15 m as well as suspended sediment transport. A series of numerical simulations is presented and compared with scaled laboratory experiments, with the objective of testing the sensitivity to different flow and sediment parameters and different turbulence closure schemes. Different scenarios are analyzed and a detailed comparison of preliminary laboratory tests and some selected simulations are presented. The laboratory experiments show that suspended sediment transport and deposition are determined by the initial flow pattern and by the upstream and downstream boundary conditions. In the experiments, deposition in the rectangular basin systematically developed along the left bank, although inflow and outflow were positioned symmetrically along the centre of the basin. Three major horizontal eddies developed influencing the sediment deposition pattern. Although asymmetric flow patterns are privileged, a symmetric pattern can appear from time to time. This particular behaviour could also be reproduced by a two-dimensional depth-averaged flow and sediment transport model (CCHE2D). The paper presents numerical simulations using different turbulence closure schemes (k-ε and eddy viscosity models). In spite of the symmetric setup, these generally produced an asymmetric flow pattern that can easily switch sides depending on the assumptions made for the initial and boundary conditions. When using the laboratory experiment as a reference, the most reliable n

关键词： shallow reservoir sedimentation and morphology suspended sediment Reservoir geometry influence Numerical simulations scaled physical modelling

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Liver stiffness as a predictor of hepatocellular carcinoma behavior in patients with hepatitis C related liver cirrhosis

引用

Hepatobiliary & Pancreatic Diseases International 2020年第1期19卷 22-28页

作者： sameh A Lashen Mohamed M Elshafei Fahmy H Hablass Eman A Alsayed Asmaa A Hassan Department of Internal Medicine Faculty of MedicineUniversity of AlexandriaAlexandriaEgypt Department of Radiology Faculty of MedicineUniversity of AlexandriaAlexandriaEgypt Department of Biomedical Informatics and Medical statistics Medical Research InstituteUniversity of AlexandriaAlexandriaEgypt

Background: Risk strati cation and prognostication of hepatocellular carcinoma (HCC) help to improve patient outcome. Herein we investigated the role of liver stiffness measurement (LsM) in the prediction of HCC behavior. Methods: Totally 121 na ve patients with HCC were included. HCC radiological evaluation and staging were done. LsM was measured using virtual touch quanti cation. Patients were divided into early to intermediate HCC (BCLC-0, A and B) and late HCC (BCLCC and D). HCC was treated according to the BCLC stage. HCC recurrence-free interval was estimated. Results: The mean LsM inside the tumor was signi cantly lower than the peri-tumoral area and the cirrhotic non-cancerous liver parts (Ps stage, the mean LsM inside the tumor and in the peri-tumoral tissue was lower than the corresponding values in the early to intermediate HCCs stage (PsM inside the tumor and in the peri-tumoral tissue negatively correlated with serum AFP, tumor vascular invasion, and stage (Ps directly correlated to LsM inside the tumor and inversely to LsM in cirrhotic non tumorous liver part. Kaplan-Meier analysis showed that the recurrence-free interval was signi cantly longer in patients with LsM inside the tumor of ≥1.25m/s compared to those with LsM inside the tumor ofs. Conclusions: LsM can serve as a potential non-invasive predictor for HCC clinical behavior and the recurrence-free interval following loco-regional treatments.

关键词： Fibrosis Hepatitis C Hepatocellular carcinoma Point shear wave Liver cirrhosis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Environmental Isotopic Characterization of Groundwater and surface Water in Northeast Missan Province,south Iraq

引用

Acta Geologica sinica(English Edition) 2014年第4期88卷 1227-1238页

作者： Hussein Badr GHaliB ali Riza sGüT selcuk University college of EngineeringGeology DepartmentSelcukTurkey Basrah University Geology DepartmentBasrahIraq

The present work studies the environmental isotopes assess groundwater characteristics of the different parts of the main aquifer in the northeast Missan Province in south of Iraq. Water samples of groundwater and surface water were collected for two dry and wet seasons during the water year of 2011-2012. The study shows that most of the groundwater in the aquifer falls above the global meteoric water line, and all the samples fall below the Mediterranean meteoric water line, indicating that these samples are a mixture of two water types. The tritium content of these samples supports this conclusion. The overall conclusion of this study indicates that there are two sources of groundwater recharge in the studied area： the ephemeral streams （Teeb and Dewerge） and major precipitation sources. According to the tritium levels at or below one tritium unit （TU） obtained from the water, supply wells are highly confined or ＂not vulnerable＂. Overall, the 3^H results imply that recent recharge has taken place during the last four to five decades. In the recharge area, the high tritium content in the southern part of the Teeb area suggests that the recharge originates from rapid infiltration of surface runoff. Therefore, the groundwater resources in the study area should be protected from contamination, because it will influence the aquifer in a relatively short period of time if any contamination enters the recharge areas of the aquifer.

关键词： Groundwater recharge Tritium environmental isotope meteoric water line Iraq

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Two-Dimensional supersonic Flow and Mixing with a Perpendicular Injection in a scramjet Combustor

引用

Journal of Thermal science 2003年第4期12卷 371-380页

作者： Mohammad ali s. Ahmed A.K.M. sadrul Islam Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh.Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh.Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 Bangladesh.

A numerical investigation has been performed on supersonic mixing of hydrogen with air in a scramjet (supersonic Combustion Ramjet) combustor and its flame holding capability by solving Two-Dimensional full Navier-stokes equations. The main flow is air entering through a finite width of inlet and gaseous hydrogen is injected perpendicularly from the side wall. An explicit Harten-Yee Non-MUsCL Modified-flux-type TVD scheme has been used to solve the system of equations, and a zero-equation algebraic turbulence model to calculate the eddy viscosity coefficient. In this study the enhancement of mixing and good flame holding capability of a supersonic combustor have been investigated by varying the distance of injector position from left boundary keeping constant the backward-facing step height and other calculation parameters. The results show that the configuration for small distance of injector position has high mixing efficiency but the upstream recirculation can not evolved properly which is an important factor for flame holding capability. On the other hand, the configuration for very long distance has lower mixing efficiency due to lower gradient of hydrogen mass concentration on the top of injector caused by the expansion of side jet in both upstream and downstream of injector. For moderate distance of injector position, large and elongated upstream recirculation can evolve which might be activated as a good flame holder.

关键词： scramjet engine TVD scheme finite width of inlet supersonic mixing parallel air stream flame holding.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Band structure,Fermi surface,elastic,thermodynamic,and optical properties of AlZr3,AlCu3,and AlCu2Zr:First-principles study

引用

Chinese Physics B 2016年第8期25卷 103-112页

作者： Parvin R Parvin F ali M s Islam A K M A Department of Physics Rajshahi University Rajshahi-6205 Bangladesh Department of Physics Pabna University of Science and Technology Pabna 6600 Bangladesh International Islamic University Chittagong 154/A College Road Chittagong-4203 Bangladesh

The electronic properties（Fermi surface,band structure,and density of states（DOs）） of Al-based alloys AlM3（M=Zr and Cu） and AlCu2Zr are investigated using the first-principles pseudopotential plane wave method within the generalized gradient approximation（GGA）.The structural parameters and elastic constants are evaluated and compared with other available ***,the pressure dependences of mechanical properties of the compounds are *** temperature dependence of adiabatic bulk modulus,Debye temperature,specific heat,thermal expansion coefficient,entropy,and internal energy are all obtained for the first time through quasi-harmonic Debye model with phononic effects for T = 0 K-100 *** parameters of optical properties（dielectric functions,refractive index,extinction coefficient,absorption spectrum,conductivity,energy-loss spectrum,and reflectivity） of the compounds are calculated and discussed for the first *** reflectivities of the materials are quite high in the IR-visible-UV region up to ~ 15 eV,showing that they promise to be good coating materials to avoid solar *** of the properties are also compared with those of the Al-based Ni3 Al compound.

关键词： first principle calculations Fermi surface elastic moduli entropy and internal energy optical properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Bright, periodic, compacton and bell-shape soliton solutions of the extended QZK and (3+1)-dimensional ZK equations

引用

Communications in Theoretical Physics 2021年第10期73卷 23-35页

作者： M ali Akbar Md Abdul Kayum M s Osman Department of Applied Mathematics University of RajshahiBangladesh Department of Computer science&Engineering North Bengal International UniversityRajshahiBangladesh Department of Mathematics Faculty of ScienceCairo UniversityGiza 12613Egypt

The(3+1)-dimensional Zakharov–Kuznetsov(ZK) and the new extended quantum ZK equations are functional to decipher the dense quantum plasma, ion-acoustic waves, electron thermal energy,ion plasma, quantum acoustic waves, and quantum Langmuir waves. The enhanced modified simple equation(EMsE) method is a substantial approach to determine competent solutions and in this article, we have constructed standard, illustrative, rich structured and further comprehensive soliton solutions via this method. The solutions are ascertained as the integration of exponential, hyperbolic,trigonometric and rational functions and formulate the bright solitons, periodic, compacton, bellshape, parabolic shape, singular periodic, plane shape and some new type of solitons. It is worth noting that the wave profile varies as the physical and subsidiary parameters change. The standard and advanced soliton solutions may be useful to assist in describing the physical phenomena previously mentioned. To open out the inward structure of the tangible incidents, we have portrayed the three-dimensional, contour plot, and two-dimensional graphs for different parametric values. The attained results demonstrate the EMsE technique for extracting soliton solutions to nonlinear evolution equations is efficient, compatible and reliable in nonlinear science and engineering.

关键词： (3+1)-dimensional ZK the extended QZK equation enhanced modified simple equation method soliton solutions NLEEs

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quantum point defects in 2D materials-the QPOD database

引用

npj Computational Materials 2022年第1期8卷 532-547页

作者： Fabian Bertoldo sajid ali simone Manti Kristian s.Thygesen CAMD Computational Atomic-Scale Materials DesignDepartment of PhysicsTechnical University of Denmark2800Kgs.LyngbyDenmark

Atomically thin two-dimensional(2D)materials are ideal host systems for quantum defects as they offer easier characterisation,manipulation and read-out of defect states as compared to bulk *** we introduce the Quantum Point Defect(QPOD)database with more than 1900 defect systems comprising various charge states of 503 intrinsic point defects(vacancies and antisites)in 82 different 2D semiconductors and *** Atomic simulation Recipes(AsR)workflow framework was used to perform density functional theory(DFT)calculations of defect formation energies,charge transition levels,Fermi level positions,equilibrium defect and carrier concentrations,transition dipole moments,hyperfine coupling,and zero-field *** states and photoluminescence spectra were calculated for selected high-spin *** this paper we describe the calculations and workflow behind the QPOD database,present an overview of its content,and discuss some general trends and correlations in the *** analyse the degree of defect tolerance as well as intrinsic dopability of the host materials and identify promising defects for quantum technological *** database is freely available and can be browsed via a web-app interlinked with the Computational 2D Materials Database(C2DB).

关键词： database Quantum point

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

引用

Neural Regeneration Research 2025年第2期20卷 394-401页

作者： Josep Tomàs Víctor Cilleros-Mañé Laia Just-Borràs Marta Balanyà-segura Aleksandra Polishchuk Laura Nadal Marta Tomàs Carolina silvera-simón Manel M.santafé Maria A.Lanuza Unitat d’Histologia i Neurobiologia(UHNeurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorB

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

KAI（sO4）2-12H2O （Alum） Catalyzed One-Pot Three-Component synthesis of 2-Alkyl and 2-Aryl-4（3H）-quinazolinone under Microwave Irradiation and solvent Free Conditions

引用

Chinese Journal of Chemistry 2011年第9期29卷 1982-1984页

作者： Mohammadi, ali A. sadat Hossini, s. s.t Department of Chemistry Sabzevar Branch Islamic Azad University Sabzevar Iran University of Applied science and Technology Tehran P.. O. Box 14155-1644 Tehran Iran

Twenty 2,3-disubstituted-4（3H）-quinazolinones were synthesed by one-pot three-component method with isa- toic anhydride, orthoesters and amines as raw materials in the presence of KAI（sO4）2·12H2O （Alum） under micro- wave irradiation and solvent-free conditions. 6-Bromo-2-propyl-3-p-tolylquinazolin-4（3H）-one （4m）, 6-bromo-2- methyl-3-phenethylquinazolin-4（3H）-one （4n） and 6-bromo-2-ethyl-3-phenethylquinazolin-4（3H）-one （40） were characterized by IR, 1H NMR, 13C NMR and elemental analysis.

关键词： isatoic anhydride orthoesters ammonium acetate 4(3H)-quinazolinone multi component micro-wave-assisted reactions

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

NOx emissions of turbofan powered unmanned aerial vehicle for complete flight cycle

引用

Chinese Journal of Aeronautics 2020年第6期33卷 1683-1691页

作者： ali DINC College of Engineering and Technology American University of the Middle EastKuwait

Unmanned Aerial Vehicles(UAVs) have been getting more and more popular in both civil and military arena. similar to manned aircraft, their propulsion systems or engines emit harmful gases such as nitrogen oxides. since UAVs have different mission profiles and operational parameters than manned aircraft, it is worthy to investigate their NOx emissions. Therefore, in this study, NOx emissions of a turbofan powered UAV for complete flight cycle was calculated and optimized within a range of altitude and speed parameters. NOx emissions were calculated based on ICAO ground test data and corrected to any speed and altitude during flight legs using both Boeing Fuel Flow Method 2 and DLR Fuel Flow Method. Total NOx emissions were calculated for complete flight cycles for different altitude and speed parameters. Numerical results were presented graphically and additionally optimization studies were conducted. Optimization studies include determination and comparison of speed and altitude for minimum NOx emissions by the two fuel flow methods and maximum loiter time achievable by UAV.

关键词： Aircraft performance Cycle analysis NOv emissions Optimization Turbofan cnlgine UAV

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：