Search Results - (Author, Cooperation:K. C. Cheng)

2011-08-06

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Antimalarials/chemistry/*pharmacology ; Biological Evolution ; Chromosome Mapping ; Drug Combinations ; *Drug Resistance/genetics ; *Genes, Protozoan ; Genetic Linkage ; Genetic Loci ; *Genome, Protozoan ; Genome-Wide Association Study ; High-Throughput Screening Assays ; Inhibitory Concentration 50 ; Membrane Transport Proteins/genetics ; Molecular Structure ; Multidrug Resistance-Associated Proteins/genetics ; Mutation ; *Parasitic Sensitivity Tests ; Plasmodium falciparum/*drug effects/*genetics/growth & development/metabolism ; Polymorphism, Single Nucleotide ; Protozoan Proteins/genetics ; Structure-Activity Relationship

2018-11-16

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Materials Science

1089-7666

AIP Digital Archive

Physics

The simultaneous effects of curvature, rotation and heating/cooling in channel flow complicate the flow and heat transfer characteristics beyond those observed in the channels with simple curvature or rotation. The phenomena encountered are examined for steady, hydrodynamically and thermally fully developed flow in square channels. The governing equations are solved numerically by using a finite-volume method. Certain hitherto unknown flow patterns are found. And the results show both the nature of the flow transition and the effect of this transition on the distributions of temperature, friction factor and Nusselt number in a square channel. © 1996 American Institute of Physics.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1551-2916

Blackwell Publishing Journal Backfiles 1879-2005

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

The changes in the structure and optical properties of indium tin oxide (ITO) thin films that were subjected to water electrolysis using an alternating current power source were investigated. X-ray diffraction indicated that the film was reduced to metallic indium after the treatment. Scanning electron microscopy revealed that the film became porous after the treatment. These structural changes had led to a dramatic degradation in the optical properties of ITO. The electrochemical mechanism responsible for the changes was discussed.

Electronic Resource

0003-9861

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] IN our previous communications in Nature1, we have given an account of the bearing of the principle of reciprocity on the theory of elementary particles, with particular reference to the determination of the natural rest masses. Attention has now been given to the application of ...

Electronic Resource

0378-1119

3α-hydroxysteroid dehydrogenase ; Recombinant DNA ; gene structure

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

0960-0760

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

0960-0760

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

0960-0760

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

0305-0491

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

1432-1181

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

Zusammenfassung Nichtstationäre natürliche Konvektion in horizontalen Zylindern mit stetig fallender Wand-temperatur wurde numerisch berechnet und zwar für Pr=0,7, 10 und 100 im Bereich der modifizierten Grashof-Zahl Gra von 103 bis 109. Mitgeteilt werden die zeitabhängigen Stromlinien- und Temperaturf eider so wie der örtliche und der totale Wärmeübergang. Für den quasistationären Fall wird eine verallgemeinerte Nusselt-Funktion für Pr ⩾0,7 und GrPr 〈 107 angegeben.

Abstract Transient natural convection in horizontal cylinders with wall temperature decreasing at a constant rate is approached by a numerical method. Numerical solutions are obtained for Pr=0.7, 10, 100 and a range of modified Grashof numbers Gra=103 ∼ 109. The time-dependent flow and temperature fields, local and overall heat transfer rates are presented. For quasi-steady state, a generalized correlation equation for Nusselt number valid for Pr ⩾0.7 and GrPr 〈 107 is developed.

Electronic Resource

1432-1181

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

Zusammenfassung Das Problem der Wärmeübertragung im thermischen Einlauf einer Hartmannströmung im ebenen Spalt mit einheitlichen, aber ungleichen Wandtemperaturen wurde unter Berücksichtigung viskoser Dissipation, Joulescher Heizung und axialer Wärmeleitung mit Hilfe einer Entwicklung nach Eigenfunktionen behandelt. Die Koeffizienten der Entwicklung für nichtorthogonale Eigenfunctionen wurde nach einer Methode für nichtorthogonale Reihen nach Kantorovicz und Krylow [21] berechnet. Numerische Ergebnisse werden für den Eintrittsparameter θo=1 und die Bedingung für den offenen Stromkreis K=1 erhalten. Die Parameterwerte Ha=0, 2, 6, 10 und Br=0, −1 werden für die jeweiligen Werte der Hartmann- und der Brinckman-Zahl betrachtet.

Abstract The problem of thermal entry heat transfer for Hartmann flow in parallel-plate channels with uniform but unequal wall temperatures considering viscous dissipation, Joule heating and axial conduction effects is approached by the eigenfunction expansion method. The series expansion coefficients for the nonorthogonal eigenfunctions are obtained by using a method for nonorthogonal series described by Kantorovich and Krylov [21]. Numerical results are obtained for the case with entrance condition parameter θo=1 and open circuit condition K=1. The parametric values of Ha=0, 2, 6, 10 and Br=0, −1 are considered for Hartmann and Brinkman numbers, respectively.

Electronic Resource

1573-1987

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract A theoretical investigation of laminar flow development in curved parallel-plate channels based on boundary layer approximation is performed employing a numerical method for the entrance conditions of uniform, parabolic and triangular velocity profiles. The axial and transverse velocity developments are presented for curvature ratio λ=0.5. The numerical results for pressure drop and entrance length are also presented for the curvature ratio λ ranging from 0 to 0.5. A comparison is made with the available theoretical results for the limiting case of the plane parallel-plate channel. The threshold of significant curvature ratio effects on entry flow is identified.

Electronic Resource

1573-1987

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract A linear stability analysis is used to study the conditions marking the onset of secondary flow in the form of longitudinal vortices for plane Poiseuille flow of water in the thermal entrance region of a horizontal parallel-plate channel by a numerical method. The water temperature range under consideration is 0∼30°C and the maximum density effect at 4°C is of primary interest. The basic flow solution for temperature includes axial heat conduction effect and the entrance temperature is taken to be uniform at far upstream location jackie=−∞ to allow for the upstream heat penetration through thermal entrance jackie=0. Numerical results for critical Rayleigh number are obtained for Peclet numbers 1, 10, 50 and thermal condition parameters (λ 1, λ 2) in the range of −2.0≤λ 1≤−0.5 and −1.0≤λ 2≤1.4. The analysis is motivated by a desire to determine the free convection effect on freezing or thawing in channel flow of water.

Electronic Resource

1573-1987

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract The effects of free convection on thermal entrance region problem and liquid solidification-free zone in a convectively-cooled horizontal square channel are studied by numerical method for steady-state fully developed laminar conditions using the large Prandtl number assumption. The Rayleigh number effects on the heat transfer results and the length of liquid solidification-free zone are investigated for Biot number of 2 and 20. It is concluded that the free convection effects should be included in the analysis of ice formation in a convectively-cooled pipe or channel when the Rayleigh number is greater than say 104.

Electronic Resource

1573-1987

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract A numerical solution using a combination of boundary vorticity method and line iterative relaxation method is presented for the hydrodynamically and thermally fully developed combined free and forced laminar convection with upward flow in inclined tubes subjected to the thermal boundary conditions of axially uniform wall heat flux and peripherally uniform wall temperature at any axial position. The numerical solution converges up to a reasonably high value of the characteristic parameter where an asymptotic behaviour for flow and heat transfer resultsfalready appears, and further results can be obtained by a linear extrapolation. The tube inclination angle or body-force orientation effects on flow and heat transfer characteristics are clarified for upward laminar flow configuration, and show that in high Rayleigh number regime the tube orientation effect has considerable influence on the results in the neighborhood of horizontal direction. Typical graphical results for flow and heat transfer are presented, mainly to illustrate the effects of Rayleigh number and tube inclination. The numerical results show that the perturbation method is invalid for the present problem.

Electronic Resource

1573-1987

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract The thermal entrance region heat transfer problem (Graetz problem) for fully developed laminar flow in curved pipes with uniform wall heat flux is approached by an alternating direction implicit method for Dean numbers ranging from 0 to an order of 100. The effects of using several different finite-difference approximations for convective terms due to secondary flow in the energy equation on heat transfer result are studied. The effect of secondary flow on developing temperature field in the thermal entrance region is studied by considering the temperature profiles, isothermals and axial distributions of average wall temperature and bulk temperature. Heat transfer results are presented for Pr = 0.1, 0.7, 10 and 500.

Electronic Resource

1573-1987

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract The analytical solution to Graetz problem with uniform wall heat flux is extended by including the viscous dissipation effect in the analysis. The analytical solution obtained reduces to that of Siegel, Sparrow and Hallman neglecting viscous dissipation as a limiting case. The sample developing temperature profiles, wall and bulk temperature distributions and the local Nusselt number variations are presented to illustrate the viscous dissipation effects. It is found that the role of viscous dissipation on thermal entrance region heat transfer is completely different for heating and cooling at wall. In the case of cooling at wall, a critical value of Brinkman number, Br c=−11/24, exists beyond which (−11/24〈Br〈0) the fluid bulk temperature will always be less than the uniform entrance temperature indicating the predominance of cooling effect over the viscous heating effect. On the other hand, with Br 〈 Br c the bulk temperature T b will approach the wall temperature T w at some downstream position and from there onward the bulk temperature T b becomes less than the wall temperature T w with T w 〉 B b 〉 T 0 indicating overall heating effect for the fluid. The numerical results for the case of cooling at wall Br 〈 0 are believed to be of some interest in the design of the proposed artctic oil pipeline.

Electronic Resource