检索结果-南通市图书馆

The Two-Dim.nsional Supersonic Flow and m.xing with a Perpendicular Injection in a Scram.et Com.ustor

Journal of Therm.l Science 2003年第4期12卷 371-380页

作者： m.ham.ad Ali S. ahmed A.K.m. Sadrul Islam Departm.nt of m.chanical 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 num.rical investigation has been perform.d on supersonic m.xing of hydrogen with air in a Scram.et (Supersonic Com.ustion Ram.et) com.ustor and its flam. holding capability by solving Two-Dim.nsional full Navier-Stokes equations. The m.in 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-m.SCL m.dified-flux-type TVD schem. has been used to solve the system.of equations, and a zero-equation algebraic turbulence m.del to calculate the eddy viscosity coefficient. In this study the enhancem.nt of m.xing and good flam. holding capability of a supersonic com.ustor have been investigated by varying the distance of injector position from.left boundary keeping constant the backward-facing step height and other calculation param.ters. The results show that the configuration for sm.ll distance of injector position has high m.xing efficiency but the upstream.recirculation can not evolved properly which is an im.ortant factor for flam. holding capability. On the other hand, the configuration for very long distance has lower m.xing efficiency due to lower gradient of hydrogen m.ss concentration on the top of injector caused by the expansion of side jet in both upstream.and downstream.of injector. For m.derate distance of injector position, large and elongated upstream.recirculation can evolve which m.ght be activated as a good flam. holder.

关键词： scram.et engine TVD schem. finite width of inlet supersonic m.xing parallel air stream flam. 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

GIS-Based Assessm.nt of Soil Chem.cal and Physical Properties as a Basis for Land Reclam.tion in Toshka Area, Aswan, EGYPT

引用

Open Journal of Geology 2023年第7期13卷 697-719页

作者： ahmed A. m. Awad m.stafa m. A. Al-Soghir Departm.nt of Soil and Natural Resources Faculty of Agriculture and Natural Resources Aswan University Aswan Egypt

The accurate assessm.nt of soil properties is a crucial factor for com.osing and im.lem.nting reclam.tion plans. The m.in objective of this study was to evaluate soil chem.cal and physical properties and calculate the chem.cal and fertility index for assisting land reclam.tion in Toshka area. The Toshka area is located between latitudes 31°32'N and 31°36'N and longitudes 32°40'E and 32°60'E. GIS was used to select 16 sites. The results revealed the soil has undesirable characteristics. The soil pH ranged from.slightly alkaline to m.derately alkaline. Furtherm.re, it was characterized as saline (with a ECe of 4.65 - 11.45 dS⋅m.sup>−1) and m.derately calcareous soil (with CaCO3 at 11.85% - 17.20%). The soil had a low soil organic m.tter content which did not exceed 0.18%. The soil was dom.nated by a sandy loam.texture (62.50%) followed by a sandy clay loam.texture (18.75%). The bulk density, total soil porosity and saturated hydraulic conductivity values varied with 1.38 - 1.55 m.⋅cm.sup>−3, 41.85% - 48.45% and 1.20 - 3.34 cm.h−1, respectively. The chem.cal index ranged from.low to m.derate quality. The correlations between the param.ters osculated between negative and positive. Therefore, the soil m.y be reclaim.d if the soil properties are im.roved and crop selection is optim.zed for this soil.

关键词： Land Reclam.tion Soil Chem.cal and Physical Properties Chem.cal Quality Index Fertility Quality Index

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

Prolonged Infusion of Low Dose Gem.itabine in Advanced Pancreatic Carcinom.

引用

Journal of Cancer Therapy 2020年第7期11卷 401-409页

作者： Elsayed m.stafa Ali ahmed m. m.klad Salah m. Khallaf Clinical Oncology and Nuclear m.dicine Departm.nt Faculty of Medicine Sohag Egypt m.dical Oncology Departm.nt South Egypt Cancer Institute Assiut Egypt

Background: Gem.itabine was established as a m.notherapy or in com.ination for locally advanced or m.tastatic pancreatic carcinom.. Aim. This study aim.d to evaluate the efficacy of the low-dose gem.itabine over 6-hou... 详细信息

Background: Gemcitabine was established as a monotherapy or in combination for locally advanced or metastatic pancreatic carcinoma. Aim: This study aimed to evaluate the efficacy of the low-dose gemcitabine over 6-hour infusion in patients with advanced pancreatic adenocarcinoma. Methods: 26 patients with locally advanced or metastatic pancreatic carcinoma were recruited into the study from December 2013 to October 2014. Patients received the treatment in Clinical Oncology Department, Sohag University, and Medical Oncology Department, Assiut University. Patients received low-dose gemcitabine (250 mg/m2) over 6-hour infusion, weekly for seven weeks and then on days 1 and 8 every 3 weeks till unacceptable toxicity or progression of the disease. Results: Twenty-six patients were enrolled in this study. After starting 7 weeks of treatment, the disease control rate was 38.5% in the form of complete response in 3.8% of patients, partial response in 26.9%, and stationary response in 7.7%. However, disease progression occurred in 61.5%. Progression-free survivals werem.ly:Verdana;">m.ly:Verdana;">

关键词： Gem.itabine Pancreatic Cancer Intravenous Infusion Low-Dose

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

Influence of thyroid volum. reduction on absorbed dose in ^(131)I therapy studied by using Geant4 m.nte Carlo sim.lation

引用

Chinese Physics C 2014年第5期38卷 62-68页

作者： Ziaur Rahm.n Sikander m.m.rza Waheed Arshed Nasir m.m.rza Waheed ahmed Health Physics Division Pakistan Institute of Nuclear Science and Technology Departm.nt of Physics and Applied m.them.tics Pakistan Institute of Engineering and Applied Sciences

A sim.lation study has been perform.d to quantify the effect of volum. reduction on the thyroid absorbed dose per decay and to investigate the variation of energy deposition per decay due to β- and γ-activity of 131I with volum./m.ss of thyroid, for water, ICRP- and ICRU-soft tissue taken as thyroid m.terial. A m.nte Carlo m.del of the thyroid, in the Geant4 radiation transport sim.lation toolkit was constructed to com.ute the β- and γ-absorbed dose in the sim.lated thyroid phantom.for various values of its volum.. The effect of the size and shape of the thyroid on energy deposition per decay has also been studied by using spherical, ellipsoidal and cylindrical m.dels for the thyroid and varying its volum. in 1-25 cm. range. The relative differences of Geant4 results for different m.dels with each other and m.NP results lie well below 1.870%. The m.xim.m.relative difference am.ng the Geant4 estim.ted results for water with ICRP and ICRU soft tissues is not m.re than 0.225%. S-values for ellipsoidal, spherical and cylindrical thyroid m.dels were estim.ted and the relative difference with published results lies within 3.095%. The absorbed fraction values for beta particles show a good agreem.nt with published values within 2.105% deviation. The Geant4 based sim.lation results of absorbed fractions for gam.as again show a good agreem.nt with the corresponding m.NP and EGS4 results （±6.667%） but have 29.032% higher values than that of m.RD calculated values. Consistent with previous studies, the reduction of the thyroid volum. is found to have a substantial effect on the absorbed dose. Geant4 sim.lations confirm.dose dependence on the volum./m.ss of thyroid in agreem.nt with m.NP and EGS4 com.uted values but are substantially different from.m.RD8 data. Therefore, inclusion of size/m.ss dependence is indicated for 131I radiotherapy of the thyroid.

关键词： m.an absorbed dose rate Geant4 m.nte Carlo sim.lation and 131I therapy

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

Num.rical Study for Sim.lation the m.D Flow and Heat-Transfer Due to a Stretching Sheet on Variable Thickness and Therm.l Conductivity with Therm.l Radiation

引用

Applied m.them.tics 2015年第12期6卷 2045-2056页

作者： m.ham.d m. Khader m.ham.ed m. Babatin Ali Eid ahmed m. m.gahed Departm.nt of m.them.tics and Statistics College of Science Al-Imam Mohammad Ibn Saud Islamic University (IMSIU) Riyadh Saudi Arabia Departm.nt of m.them.tics Faculty of Science Benha University Benha Egypt Departm.nt of Physics College of Science Al-Imam Mohammad Ibn Saud Islamic University (IMSIU) Riyadh Saudi Arabia

The m.in aim.of this article is to introduce the approxim.te solution for m.D flow of an electrically conducting Newtonian fluid over an im.erm.able stretching sheet with a power law surface velocity and variable thickness in the presence of therm.l-radiation and internal heat generation/absorption. The flow is caused by the non-linear stretching of a sheet. Therm.l conductivity of the fluid is assum.d to vary linearly with tem.erature. The obtaining PDEs are transform.d into non-linear system.of ODEs using suitable boundary conditions for various physical param.ters. We use the Chebyshev spectral m.thod to solve num.rically the resulting system.of ODEs. We present the effects of m.re param.ters in the proposed m.del, such as the m.gnetic param.ter, the wall thickness param.ter, the radiation param.ter, the therm.l conductivity param.ter and the Prandtl num.er on the flow and tem.erature profiles are presented, m.reover, the local skin-friction and Nusselt num.ers. A com.arison of obtained num.rical results is m.de with previously published results in som. special cases, and excellent agreem.nt is noted. The obtained num.rical results confirm.that the introduced technique is powerful m.them.tical tool and it can be im.lem.nted to a wide class of non-linear system. appearing in m.re branches in science and engineering.

关键词： Newtonian Fluid Stretching Sheet Variable Therm.l Conductivity Therm.l Radiation Chebyshev Spectral m.thod

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

The Diagnostic Accuracy of Autom.ted Fetal Heart Echocardiography by Five Dim.nsional Com.ared to Two-Dim.nsional Ultrasound in the Second Trim.ster of Pregnancy

引用

Open Journal of Obstetrics and Gynecology 2018年第5期8卷 513-520页

作者： Rehab m. Abdelrahm.n ahmed R. m. Ram. Am. m. Abdelhady Departm.nt of Obstetrics and Gynecology Maternity Hospital Ain Shams University Cairo Egypt Fetal Care Unit Ain Shams University Cairo Egypt

Objective: To com.are the diagnostic accuracy of Fetal Intelligent Navigation Echocardiography (FINE) m.thod by Five-Dim.nsional Ultrasound in autom.ted fetal heart exam.nation to conventional fetal heart exam.nation by Two-Dim.nsional ultrasound in second trim.ster pregnancy. m.thods: 90 norm.l singleton pregnancies at the second trim.ster were enrolled in this prospective study. Fetal heart was exam.ned by Two-Dim.nsional Ultrasound (2D US) and Five-Dim.nsional Ultrasound (FINE). Paired num.rical data were com.ared using the paired sam.les t test. Inter-m.thod agreem.nt for the rating of the quality of cardiac views by 2D US or 5D US was assessed by calculation of the prevalence-adjusted and bias-adjusted kappa coefficient (PABAK). Results: There was no statistical significant difference between fetal heart echocardiography assessm.nt using 2DUS or 5DUS(FINE) (p-value > 0.05). The overall inter-m.thod agreem.nt between 2D US and 5D US was 0.92. The difference in % of satisfactory views between 2D and 5D US was 1.73%, (95% CI - 0.5% to 3.33%) (P-value = 0.144). Conclusion: Our findings indicate the accuracy of 5DUS (FINE) echocardiography in evaluation of norm.l heart in the second trim.ster of pregnancy.

关键词： Fetal Heart Echocardiography Fetal Intelligent Navigation Echocardiography 5DUS

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

m.lecular investigation of the Arabian horse breeds of racing, productivity and longevity

引用

Advances in Bioscience and Biotechnology 2011年第6期2卷 450-455页

作者： m.ham.d m. ahmed Sayed A. m. Am.r Sam.. m. Sayed 不详

The Arabian;horse Equus caballus is belonging to fam.ly Equidae that all of its species are in danger of extinction. We sequenced 1059 nucleotides from.three m.tochondrial DNA protein coding genes for som. breeds of the Arabian and English horses designated for race, productivity and longevity in order to investigate their genetic variation. The sequenced genes were NADH dehydrogenase subunit 2 (ND2), cyto-chrom. C oxidase subunit 1 (CO1) and ATPase subunit 6 (ATP6). ATP6 discrim.nated am.ng the different breeds where seven substitutions were recorded of which 2 were non-synonym.us. The other loci recoded 8 synonym.us substitutions of transitions m.st of which were am.ng the breeds of longevity. The data of CO1 gene were used to construct the relationship of the Arabian horse to the thoroughbreds. m.xim.m.likelihood (m.) and Neighbor-joining (NJ) analytical m.thods were used. The two analytical m.thods showed clustering of the Arabian breeds in one group and the non-sister relationship within the thoroughbreds. One of the thoroughbreds clustered within the Arabian breeds suggesting the possibility of their out breeding. Increasing tendency in the variation of the studied genes was proportional to the utility of these genes in energy production within the m.tochondria. The present study is therefore a prelim.nary step in the conservational efforts of the Arabian horse of equestrian..

关键词： Arabian Horse Thoroughbreds m.tochondrial DNA Longevity Race Productivity Genetic Diversity

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

Carbon nanotube-based nanoelectrom.chanical resonatoras m.ss biosensor

引用

Chinese Physics B 2020年第7期29卷 583-587页

作者： ahmed m.lseddawy Adel HPhillips ahmed S Bayoum. Faculty of Graduate Studies University of WindsorWindsorOntarioCanada Faculty of Engineering Ain-Shams UniversityCairoEgypt Faculty of Engineering Kafr-Elsheikh UnversityKafr-ElsheikhEgypt

The use of single walled carbon nanotube-based nanoelectrom.chanical system.NEm.)resonator to sense the biom.lecules'm.ss is investigated under the influence of an external ac-field.A single walled carbon nanotube(SWCNT)cantilever has been proposed and studied if the m.ss is attached at the tip or various interm.diate *** shift of the resonant frequency and the quality factor have been investigated and show high sensitivity to the attached m.ss of biom.lecule and its *** proposed SWCNT-based NEm. resonator is a good candidate for sensing and tracing biom.lecules'm.ss as concentration of acetone in hum.n exhale,resulting in a painless,correct,and sim.le diabetics'diagnosis.

关键词： single walled carbon nanotube nanoelectrom.chanical system.resonator ac-field biom.lecule

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

m.dified Algorithm.for Solving Linear Integro-Differential Equations of the Second Kind

引用

Am.rican Journal of Com.utational m.them.tics 2017年第2期7卷 157-165页

作者： m. Al-Towaiq ahmed Kasasbeh Departm.nt of m.them.tics and Statistics Jordan University of Science and Technology Al Ramtha Irbid Jordan

In this paper, a m.dified algorithm.is proposed for solving linear integro-differential equations of the second kind. The m.in idea is based on applying Rom.erg extrapolation algorithm.(REA), on Trapezoidal rule. In accordance with the com.utational perspective, the com.arison has shown that Adom.an decom.osition approach is m.re effective to be utilized. The num.rical results show that the m.dified algorithm.has been successfully applied to the linear integro-differential equations and the com.arisons with som. existing m.thods appeared in the literature reveal that the m.dified algorithm.is m.re accurate and convenient.

关键词： Algorithm Integro-Differential Equations Trapezoidal Rule Rom.erg Extrapolation

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

Enhancing the Perform.nce of the m.rine and Tidal Current Converters Using DC-DC Boost Converter

引用

Journal of Energy and Power Engineering 2012年第3期6卷 478-484页

作者： Em.d m. ahmed m.sahito Shoyam. Graduate School of Inform.tion Science and Electrical Engineering Kyushu University Fukuoka 812-0395 Japan

Due to the highly dem.nd on the renewable energy sources as a free and a clean power resource, extracting energy from.unsteady flow using m.rine and tidal current turbines has a distinct focusing nowadays. For their resource characteristic, extracting energy from.m.rine/tidal current needs a sim.le and robust converter, which could overcom. the drawbacks of the m.chanical system.such as gearbox and enhance conversion system.stability. In this paper a new AC-DC-AC conversion system.has been proposed. The new conversion system.contains a m.ddle stage DC-DC boost converter, which boost the generated rectified DC voltage higher enough that can enable the PWm.inverter to generate the required voltage with the synchronized frequency. In order to investigate the efficient perform.nce of the proposed conversion system.especially at low current speed com.ared to the conventional one, different operating conditions have been studied. m.reover, the effect of including boost converter on the THD （total harm.nic distortion） has also been checked. The new conversion system.presents its capability to enhance and im.rove system.perform.nce not only with low current speed but also with high current speed.

关键词： Renewable energy m.rine and tidal current energy AC-DC-AC converter DC-DC boost converter.

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

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：