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Boundary layer flow of third grade nanofluid with Newtonian heating and viscous dissipation 被引量:8
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作者 S.A.Shehzad Tariq Hussain +2 位作者 T.Hayat M.Ramzan A.Alsaedi 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期360-367,共8页
Two-dimensional boundary layer flow of an incompressible third grade nanofluid over a stretching surface is investigated.Influence of thermophoresis and Brownian motion is considered in the presence of Newtonian heati... Two-dimensional boundary layer flow of an incompressible third grade nanofluid over a stretching surface is investigated.Influence of thermophoresis and Brownian motion is considered in the presence of Newtonian heating and viscous dissipation.Governing nonlinear problems of velocity, temperature and nanoparticle concentration are solved via homotopic procedure.Convergence is examined graphically and numerically. Results of temperature and nanoparticle concentration are plotted and discussed for various values of material parameters, Prandtl number, Lewis number, Newtonian heating parameter, Eckert number and thermophoresis and Brownian motion parameters. Numerical computations are performed. The results show that the change in temperature and nanoparticle concentration distribution functions is similar when we use higher values of material parameters β1 andβ2. It is seen that the temperature and thermal boundary layer thickness are increasing functions of Newtonian heating parameter γ.An increase in thermophoresis and Brownian motion parameters tends to an enhancement in the temperature. 展开更多
关键词 加热参数 边界层流 粘性耗散 纳米流体 牛顿 布朗运动 纳米粒子 材料参数
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Fungi as chemical industries and genetic engineering for the production of biologically active secondary metabolites 被引量:6
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作者 Abid Ali Khan Nafees Bacha +3 位作者 Bashir Ahmad Ghosia Lutfullah Umar Farooq Russell John Cox 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2014年第11期859-870,共12页
Fungi is somewhere in between the micro and macro organisms which is a good source of producing biologically active secondary metabolites.Fungi have been used as tool for producing different types of secondary metabol... Fungi is somewhere in between the micro and macro organisms which is a good source of producing biologically active secondary metabolites.Fungi have been used as tool for producing different types of secondary metabolites by providing different nutrients at different laboratory conditions.The fungi have been engineered for the desired secondary metabolites by using different laboratory techniques,for example,homologous and heterologous expressions.This review reported how the fungi are used as chemical industry for the production of secondary metabolites and how they are engineered in laboratory for the production of desirable metabolites:also the biosynthetic pathways of the bio-organic-molecules were reported. 展开更多
关键词 FUNGI NATURAL products MICROBIOLOGY MOLECULAR GENETICS Chemical BIOLOG
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Size control synthesis of sulfur doped titanium dioxide (anatase) nanoparticles,its optical property and its photo catalytic reactivity for CO_2 + H_2O conversion and phenol degradation 被引量:8
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作者 S. Tajammul Hussain Khaiber Khan R. Hussain 《Journal of Natural Gas Chemistry》 CAS CSCD 2009年第4期383-391,共9页
Sulfur doped anatase TiO2 nanoparticles (3 nm- 12 nm) were synthesized by the reaction of titanium tetrachloride, water and sulfuric acid with addition of 3 M NaOH at room temperature. The electro-optical and photoc... Sulfur doped anatase TiO2 nanoparticles (3 nm- 12 nm) were synthesized by the reaction of titanium tetrachloride, water and sulfuric acid with addition of 3 M NaOH at room temperature. The electro-optical and photocatalytic properties of the synthesized sulfur doped TiO2 nanoparticles were studied along with Degussa commercial TiO2 particles (24 nm). The results show that band gap of TiO2 particles decreases from 3.31 to 3.25 eV and for that of commercial TiO2 to 3.2 eV when the particle sizes increased from 3 nm to 12 nm with increase in sulfur doping. The results of the photocatalytic activity under UV and sun radiation show maximum phenol conversion at the particle size of 4 nm at 4.80% S-doping. Similar results are obtained using UV energy for both phenol conversion and conversion of CO2+H2O in which formation of methanol, ethanol and proponal is observed. Production of methanol is also achieved on samples with a particle size of 8 and 12 nm and sulfur doping of 4.80% and 5.26%. For TiO2 particle of 4 nm without S doping, the production of methanol, ethanol and proponal was lower as compared to the S-doped particles. This is attributed to the combined electronic effect and band gap change, S dopant, specific surface area and the light source used. 展开更多
关键词 S doped TiO2 PHOTOCATALYST CO2 conversion phenol degradation UV IR radiation
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Convective heat and mass transfer in MHD mixed convection flow of Jeffrey nanofluid over a radially stretching surface with thermal radiation 被引量:6
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作者 M.BILAL ASHRAF T.HAYAT +1 位作者 A.ALSAEDI S.A.SHEHZAD 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期1114-1123,共10页
Mixed convection flow of magnetohydrodynamic(MHD) Jeffrey nanofluid over a radially stretching surface with radiative surface is studied. Radial sheet is considered to be convectively heated. Convective boundary condi... Mixed convection flow of magnetohydrodynamic(MHD) Jeffrey nanofluid over a radially stretching surface with radiative surface is studied. Radial sheet is considered to be convectively heated. Convective boundary conditions through heat and mass are employed. The governing boundary layer equations are transformed into ordinary differential equations. Convergent series solutions of the resulting problems are derived. Emphasis has been focused on studying the effects of mixed convection, thermal radiation, magnetic field and nanoparticles on the velocity, temperature and concentration fields. Numerical values of the physical parameters involved in the problem are computed for the local Nusselt and Sherwood numbers are computed. 展开更多
关键词 混合对流 径向拉伸 纳米流体 热辐射 MHD 传热传质 表面 对流边界条件
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MHD three-dimensional flow of Jeffrey fluid with Newtonian heating 被引量:6
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作者 S.A.Shehzad T.Hayat +1 位作者 M.S.Alhuthali S.Asghar 《Journal of Central South University》 SCIE EI CAS 2014年第4期1428-1433,共6页
The magnetohydrodynamic(MHD) three-dimensional flow of Jeffrey fluid in the presence of Newtonian heating is investigated. Flow is caused by a bidirectional stretching surface. Series solutions are constructed for the... The magnetohydrodynamic(MHD) three-dimensional flow of Jeffrey fluid in the presence of Newtonian heating is investigated. Flow is caused by a bidirectional stretching surface. Series solutions are constructed for the velocity and temperature fields. Convergence of series solutions is ensured graphically and numerically. The variations of key parameters on the physical quantities are shown and discussed in detail. Constructed series solutions are compared with the existing solutions in the limiting case and an excellent agreement is noticed. Nusselt numbers are computed with and without magnetic fields. It is observed that the Nusselt number decreases in the presence of magnetic field. 展开更多
关键词 磁流体动力学 三维流 加热 牛顿 双向拉伸 关键参数 MHD 温度场
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Effects of partial slip on flow of a third grade fluid 被引量:6
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作者 S. Asghar M. Mudassar Gulzar M. Ayub 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2006年第5期393-396,共4页
This paper is an analytical study of the rotating flow of a third grade fluid past a porous plate with partial slip effects. It serves as a flow model for the study of polymers. The analytic solution has been determin... This paper is an analytical study of the rotating flow of a third grade fluid past a porous plate with partial slip effects. It serves as a flow model for the study of polymers. The analytic solution has been determined using homotopy analysis method (HAM). 展开更多
关键词 Partial-slip Non-Newtonian fluid Analytic solution Homotopy analysis method
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Molecular genetic and genomic analysis of wheat milling and end-use traits in China:Progress and perspectives 被引量:5
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作者 Daowen Wang Kunpu Zhang +4 位作者 Lingli Dong Zhenying Dong Yiwen Li Abrar Hussain Huijie Zhai 《The Crop Journal》 SCIE CAS CSCD 2018年第1期68-81,共14页
Wheat is the most widely cultivated staple food crop, and multiple types of food derivatives are processed and consumed globally. Wheat grain quality(WGQ) is central to food processing and nutritional value, and is a ... Wheat is the most widely cultivated staple food crop, and multiple types of food derivatives are processed and consumed globally. Wheat grain quality(WGQ) is central to food processing and nutritional value, and is a decisive factor for consumer acceptance and commercial value of wheat cultivars. Hence, improvement in WGQ traits is top priority for both conventional and molecular wheat breeding. In this review we will focus on two important WGQ traits, grain milling and end-use, and will summarize recent progress in China. Chinese scientists have invested substantial effort in molecular genetic and genomic analysis of these traits and their effects on end-use properties. The insights and resources generated have contributed to the understanding and improvement of these traits. As high-quality genomics information and powerful genome engineering tools are becoming available for wheat, more fundamental breakthroughs in dissecting the molecular and genomic basis of WGQ are expected. China will strive to make further significant contributions to the study and improvement of WGQ in the genomics era. 展开更多
关键词 GENOMICS GLUTEN protein GRAIN HARDNESS PUROINDOLINE Wheat GRAIN quality
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Flow of Casson nanofluid with viscous dissipation and convective conditions: A mathematical model 被引量:4
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作者 T.HUSSAIN S.A.SHEHZAD +2 位作者 A.ALSAEDI T.HAYAT M.RAMZAN 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期1132-1140,共9页
The magnetohydrodynamic(MHD) boundary layer flow of Casson fluid in the presence of nanoparticles is investigated.Convective conditions of temperature and nanoparticle concentration are employed in the formulation. Th... The magnetohydrodynamic(MHD) boundary layer flow of Casson fluid in the presence of nanoparticles is investigated.Convective conditions of temperature and nanoparticle concentration are employed in the formulation. The flow is generated due to exponentially stretching surface. The governing boundary layer equations are reduced into the ordinary differential equations. Series solutions are presented to analyze the velocity, temperature and nanoparticle concentration fields. Temperature and nanoparticle concentration fields decrease when the values of Casson parameter enhance. It is found that the Biot numbers arising due to thermal and concentration convective conditions yield an enhancement in the temperature and concentration fields. Further, we observed that both the thermal and nanoparticle concentration boundary layer thicknesses are higher for the larger values of thermophoresis parameter. The effects of Brownian motion parameter on the temperature and nanoparticle concentration are reverse. 展开更多
关键词 纳米流体 数学模型 对流 粘性耗散 边界层方程 纳米颗粒 颗粒浓度 常微分方程
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Debris flow susceptibility analysis based on the combined impacts of antecedent earthquakes and droughts: a case study for cascade hydropower stations in the upper Yangtze River, China 被引量:4
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作者 HU Gui-sheng CHEN Ning-sheng +3 位作者 TANOLI Javed Iqbal LIU Mei LIU Rong-Kun CHEN Kun-Ting 《Journal of Mountain Science》 SCIE CSCD 2017年第9期1712-1727,共16页
The upper Yangtze River region is one of the most frequent debris flow areas in China. The study area contains a cascade of six large hydropower stations located along the river with total capacity of more than 70 mil... The upper Yangtze River region is one of the most frequent debris flow areas in China. The study area contains a cascade of six large hydropower stations located along the river with total capacity of more than 70 million kilowatts. The purpose of the study was to determine potential and dynamic differences in debris flow susceptibility and intensity with regard to seasonal monsoon events. We analyzed this region's debris flow history by examining the effective peak acceleration of antecedent earthquakes,the impacts of antecedent droughts, the combined effects of earthquakes and droughts, with regard to topography, precipitation, and loose solid material conditions. Based on these factors, we developed a debris flow susceptibility map. Results indicate that the entire debris flow susceptibility area is 167,500 km^2, of which 26,800 km^2 falls within the high susceptibility area, with 60,900 km^2 in medium and 79,800 km^2 are in low susceptibility areas. Three of the six large hydropower stations are located within the areas with high risk of debris flows. The synthetic zonation map of debris flow susceptibility for the study area corresponds with both the investigation data and actual distribution of debris flows. The results of debris flow susceptibility provide base-line data for mitigating, assessing, controlling and monitoring of debris flows hazards. 展开更多
关键词 泥石流灾害 敏感性分析 上游地区 扬子江 梯级水电站 干旱 地震 前期
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On the MHD flow of fractional generalized Burgers' fluid with modified Darcy's law 被引量:5
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作者 T.Hayat M.Khan S.Asghar 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第3期257-261,共5页
This work is concerned with applying the fractional calculus approach to the magnetohydrodynamic (MHD) pipe flow of a fractional generalized Burgers' fluid in a porous space by using modified Darcy's relationship.... This work is concerned with applying the fractional calculus approach to the magnetohydrodynamic (MHD) pipe flow of a fractional generalized Burgers' fluid in a porous space by using modified Darcy's relationship. The fluid is electrically conducting in the presence of a constant applied magnetic field in the transverse direction. Exact solution for the velocity distribution is developed with the help of Fourier transform for fractional calculus. The solutions for a Navier-Stokes, second grade, Maxwell, Oldroyd-B and Burgers' fluids appear as the limiting cases of the present analysis. 展开更多
关键词 Modeling Generalized Burgers' fluid Fractional calculus Exact solution
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ON A CLASS OF ANALYTIC FUNCTIONS RELATED TO CONIC DOMAINS AND ASSOCIATED WITH CARLSON-SHAFFER OPERATOR 被引量:4
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作者 S.Hussain J.Sokól 《Acta Mathematica Scientia》 SCIE CSCD 2012年第4期1399-1407,共9页
Making use of the Carlson-Shaffer convolution operator, we introduce and study a new class of analytic functions related to conic domains. The main object of this paper is to investigate inclusion relations, coefficie... Making use of the Carlson-Shaffer convolution operator, we introduce and study a new class of analytic functions related to conic domains. The main object of this paper is to investigate inclusion relations, coefficient bound for this class. We also show that this class is closed under convolution with a convex function. Some applications are also discussed. 展开更多
关键词 Hadamard product (or convolution) differential subordination Carlson-Shaffer operator k-starlike functions k-uniformly convex function
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Structural and optical properties of thermally reduced graphene oxide for energy devices 被引量:3
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作者 Ayesha Jamil Faiza Mustafa +2 位作者 Samia Aslam Usman Arshad Muhammad Ashfaq Ahmad 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第8期346-352,共7页
Natural intercalation of the graphite oxide, obtained as a product of Hummer's method, via ultra-sonication of water dispersed graphite oxide has been carried out to obtain graphene oxide(GO) and thermally reduced ... Natural intercalation of the graphite oxide, obtained as a product of Hummer's method, via ultra-sonication of water dispersed graphite oxide has been carried out to obtain graphene oxide(GO) and thermally reduced graphene oxide(RGO).Here we report the effect of metallic nitrate on the oxidation properties of graphite and then formation of metallic oxide(MO) composites with GO and RGO for the first time. We observed a change in the efficiency of the oxidation process as we replaced the conventionally used sodium nitrate with that of nickel nitrate Ni(NO_3)_2, cadmium nitrate Cd(NO_3)_2,and zinc nitrate Zn(NO_3)_2. The structural properties were investigated by x-ray diffraction and observed the successful formation of composite of MO–GO and MO–RGO(M = Zn, Cd, Ni). We sought to study the effect on the oxidation process through optical characterization via UV-Vis spectroscopy and Fourier Transform Infrared(FTIR) spectroscopy.Moreover, Thermo Gravimetric Analysis(TGA) was carried out to confirm 〉 90% weight loss in each process thus proving the reliability of the oxidation cycles. We have found that the nature of the oxidation process of graphite powder and its optical and electrochemical characteristics can be tuned by replacing the sodium nitrate(NaNO_3) by other metallic nitrates as Cd(NO_3)_2, Ni(NO_3)_2, and Zn(NO_3)_2. On the basis of obtained results, the synthesized GO and RGO may be expected as a promising material in antibacterial activity and in electrodes fabrication for energy devices such as solar cell, fuel cell,and super capacitors. 展开更多
关键词 thermal properties of graphene oxide and reduced graphene oxide optical properties structuralproperties fuel cell composite materials
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Heat transfer analysis in peristaltic flow of MHD Jeffrey fluid with variable thermal conductivity 被引量:3
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作者 Q.HUSSAIN S.ASGHAR +1 位作者 T.HAYAT A.ALSAEDI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2015年第4期499-516,共18页
The effect of an inclined magnetic field in the peristaltic flow of a Jeffrey fluid with variable thermal conductivity is discussed. The temperature dependent thermal conductivity of fluid in an asymmetric channel is ... The effect of an inclined magnetic field in the peristaltic flow of a Jeffrey fluid with variable thermal conductivity is discussed. The temperature dependent thermal conductivity of fluid in an asymmetric channel is taken into account. A dimensionless nonlinear system subject to a long wavelength and a low Reynolds number is solved. The explicit expressions of the stream function, the axial velocity, the pressure gradient, and the temperature are obtained. The effects of all physical parameters on peristaltic transport and heat transfer characteristics are observed from graphical illustrations. The behaviors of θ∈ [0, π/2] and θ∈ [π/2, π] on fluid flow and heat transfer are found to be opposite. Further, the size of trapped bolus is greater for the case of the inclined magnetic field (θ≠ π/2) than that for the case of the transverse magnetic field (θ = π/2). The heat transfer coefficient decreases when the constant thermal conductivity (Newtonian) fluid is changed to the variable thermal conductivity (Jeffrey) fluid. 展开更多
关键词 inclined magnetic field variable thermal conductivity Jeffrey fluid peri-staltic transport heat transfer
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Entropy squeezing of an atom with a k-photon in the Jaynes-Cummings model 被引量:3
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作者 康冬鹏 廖庆洪 +2 位作者 Ahamd Muhammad Ashfaq 王月媛 刘树田 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第1期318-325,共8页
The entropy squeezing of an atom with a k-photon in the Jaynes Cummings model is investigated. For comparison, we also study the corresponding variance squeezing and atomic inversion. Analytical results show that entr... The entropy squeezing of an atom with a k-photon in the Jaynes Cummings model is investigated. For comparison, we also study the corresponding variance squeezing and atomic inversion. Analytical results show that entropy squeezing is preferable to variance squeezing for zero atomic inversion. Moreover, for initial conditions of the system the relation between squeezing and photon transition number is also discussed. This provides a theoretical approach to finding out the optimal entropy squeezing. 展开更多
关键词 Jaynes-Cumming model entropy squeezing variance squeezing atomic inversion
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Antibiotic susceptibility profiling and virulence potential of Campylobacter jejuni isolates from different sources in Pakistan 被引量:2
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作者 Fariha Masood Siddiqui Muhammad Akram +2 位作者 Nighat Nourccn Zobia Noreen Habib Bokhari 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2015年第3期197-202,共6页
Objective:To determine antibiotic resistance patterns and virulence potential of Campylobacter jejuni(C.jejuni) isolates from clinical human diarrheal infections,cattle and healthy broilers.Methods:Antibiotic sensitiv... Objective:To determine antibiotic resistance patterns and virulence potential of Campylobacter jejuni(C.jejuni) isolates from clinical human diarrheal infections,cattle and healthy broilers.Methods:Antibiotic sensitivity patterns of C.jejuni isolates were determined by Kirby Bauer Disc Diffusion assay.These isolates were then subjected to virulence profiling for the detection of map A(membrane-associated protein).cadF(fibronectin binding protein).wlaN(beta-1.3-galaclosyltransferase) and neu AB(sialic acid biosynthesis gene).Further C.jejuni isolates were grouped by random amplification of polymorphic DNA(RAPD) profiling.Results:A total of436 samples from poultry(n=88).cattle(n=216) and humans(n=132) from different locations were collected.Results revealed percentage of C.jejuni isolates were 35.2%(31/88).25.0%(54/216) and 11.3%(15/132) among poultry,cattle and clinical human samples respectively.Antibiotic susceptibility results showed that similar resistance patterns to cephalothin was ie.87.0%,87.1%and 89%among humans,poultry and cattle respectively,followed by sulfamethoxazolc+trimcthoprim 40.0%,38.7%and 31.0%in humans,poultry and cattle and Ampicillin 40%,32%and 20%in humans,poultry and cattle respectively.Beta-lactamase activity was detected in 40.00%humans.20.37%cattle and 32.25%in poultry C.jejuni isolates.CadF and mapA were present in all poultry,cattle and human C jejuni isolates.wlauN was not detected in any isolate and neu AB was found in 9/31(36%) poultry isolates.RAPD profiling results suggested high diversity of C.jejuni isolates.Conclusions:Detection of multidrug resistant C.jejuni strains from poultry and cattle is alarming as they can be potential hazard to humans.Moreover,predominant association of virulence factors,cadF and map A(100%each) in C.jejuni isolates from all sources and neuAB(36%) with poultry isolates suggest the potential source of transmission of diverse types of C.jejuni to humans. 展开更多
关键词 CAMPYLOBACTER JEJUNI Antibiotic SUSCEPTIBILITY VIRULENCE genes PCR RAPD
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Distillability Sudden Birth of Entanglement for Qutrit-Qutrit Systems 被引量:2
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作者 Mazhar Alit 黄江 《Chinese Physics Letters》 SCIE CAS CSCD 2014年第11期5-8,共4页
我们报导在二座统计上独立的水库之间的 distillability 的突然的出现作为 qutrit-qutrit 系统当模特儿。由两部组成的量系统的这个特征与纠纷的以前观察的现象不同突然的出生。水库的状态首先变得界限纠缠,这被发现,因此展出纠纷突... 我们报导在二座统计上独立的水库之间的 distillability 的突然的出现作为 qutrit-qutrit 系统当模特儿。由两部组成的量系统的这个特征与纠纷的以前观察的现象不同突然的出生。水库的状态首先变得界限纠缠,这被发现,因此展出纠纷突然的出生,因而由 distillability 的突然的出生列在后面,并且每当 distillability 从主要系统突然地被失去时,它必然也在水库自由的学位之中突然地出现,这被显示出。这令人吃惊的观察反映量纠纷的动态方面的另一个怪癖。 展开更多
关键词 量子纠缠 it系统 统计独立 量子系统 水库 主系统 自由度 动力学
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Excitation of defect modes from the extended photonic band-gap structures of 1D photonic lattices 被引量:2
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作者 周可雅 郭忠义 +1 位作者 Muhammad Ashfaq Ahmad 刘树田 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第1期284-288,共5页
This paper stuides numerically the model equation in a one dimensional defective photonic lattice by modifying the potential function to a periodic function. It is found that defect modes (DMs) can be regarded as Bl... This paper stuides numerically the model equation in a one dimensional defective photonic lattice by modifying the potential function to a periodic function. It is found that defect modes (DMs) can be regarded as Bloch modes which are excited from the extended photonie band-gap structure at Bloch wave-numbers with kx = 0. The DMs for both positive and negative defects are considered in this method. 展开更多
关键词 optical-induced photonic lattices photonic band-gaps defect modes
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Application of the Method of Characteristics to Population Balance Models Considering Growth and Nucleation Phenomena 被引量:2
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作者 Shahzadi Mubeen ur Rehman Shamsul Qamar 《Applied Mathematics》 2014年第13期1853-1862,共10页
The population balance modeling is regarded as a universally accepted mathematical framework for dynamic simulation of various particulate processes, such as crystallization, granulation and polymerization. This artic... The population balance modeling is regarded as a universally accepted mathematical framework for dynamic simulation of various particulate processes, such as crystallization, granulation and polymerization. This article is concerned with the application of the method of characteristics (MOC) for solving population balance models describing batch crystallization process. The growth and nucleation are considered as dominant phenomena, while the breakage and aggregation are neglected. The numerical solutions of such PBEs require high order accuracy due to the occurrence of steep moving fronts and narrow peaks in the solutions. The MOC has been found to be a very effective technique for resolving sharp discontinuities. Different case studies are carried out to analyze the accuracy of proposed algorithm. For validation, the results of MOC are compared with the available analytical solutions and the results of finite volume schemes. The results of MOC were found to be in good agreement with analytical solutions and superior than those obtained by finite volume schemes. 展开更多
关键词 Population BALANCE Modeling BATCH CRYSTALLIZATION Method of Characteristics NUCLEATION and GROWTH
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Evolution of plasma parameters in an Ar-N2/He inductive plasma source with magnetic pole enhancement 被引量:2
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作者 Maria YOUNUS N U REHMAN +3 位作者 M SHAFIQ M NAEEM M ZAKA-UL-ISLAM M ZAKAULLAH 《Plasma Science and Technology》 SCIE EI CAS CSCD 2017年第2期34-42,共9页
Magnetic pole enhanced inductively coupled plasmas (MaPE-ICPs) are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optic... Magnetic pole enhanced inductively coupled plasmas (MaPE-ICPs) are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optical emission spectroscopy were used to monitor the evolution of plasma parameters in a MaPE-ICP Ar-Na/He mixture plasma. Electron density (ne) and temperature (Te), excitation temperature (Texc), plasma potential (Vp), skin depth (6) and the evolution of the electron energy probability function (EEPF) are reported as a function of radiofrequency (RF) power, pressure and argon concentration in the mixture. It is observed that ne increases while Te decreases with increase in RF power and argon concentration in the mixture. The emission intensity of the argon line at 750.4 nm is also used to monitor the variation of the ‘high-energy tail' of the EEPF with RF power and gas pressure. The EEPF has a ‘bi-Maxwellian' distribution at low RF powers and higher pressure in a pure N2 discharge. However, it evolves into a ‘Maxwellian' distribution at RF powers greater than 70 W for pure N2, and at 50 W for higher argon concentrations in the mixture. The effect of argon concentration on the temperatures of two electron groups in the ‘bi-Maxwellian' EEPF is examined. The temperature of the low-energy electron group TL shows a decreasing trend with argon addition until the ‘thermalization' of the two temperatures occurs, while the temperature of high-energy electrons Ta decreases continuously. 展开更多
关键词 MaPE-ICP Langmuir probe OES EEPF
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Evaluation of Ordinary Least Square(OLS) and Geographically Weighted Regression(GWR) for Water Quality Monitoring:A Case Study for the Estimation of Salinity 被引量:1
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作者 NAZEER Majid BILAL Muhammad 《Journal of Ocean University of China》 SCIE CAS CSCD 2018年第2期305-310,共6页
Landsat-5 Thematic Mapper(TM) dataset have been used to estimate salinity in the coastal area of Hong Kong. Four adjacent Landsat TM images were used in this study, which was atmospherically corrected using the Second... Landsat-5 Thematic Mapper(TM) dataset have been used to estimate salinity in the coastal area of Hong Kong. Four adjacent Landsat TM images were used in this study, which was atmospherically corrected using the Second Simulation of the Satellite Signal in the Solar Spectrum(6S) radiative transfer code. The atmospherically corrected images were further used to develop models for salinity using Ordinary Least Square(OLS) regression and Geographically Weighted Regression(GWR) based on in situ data of October 2009. Results show that the coefficient of determination(R^2) of 0.42 between the OLS estimated and in situ measured salinity is much lower than that of the GWR model, which is two times higher(R^2 = 0.86). It indicates that the GWR model has more ability than the OLS regression model to predict salinity and show its spatial heterogeneity better. It was observed that the salinity was high in Deep Bay(north-western part of Hong Kong) which might be due to the industrial waste disposal, whereas the salinity was estimated to be constant(32 practical salinity units) towards the open sea. 展开更多
关键词 Landsat THEMATIC MAPPER WATER quality SALINITY remote sensing coastal WATER
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