Search Results - (Author, Cooperation:Y. Xuan)

2018-03-06

Oxford University Press

1367-4803

1460-2059

Biology

Computer Science

Medicine

2011-12-24

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Equipment Design ; *Lasers, Semiconductor ; Optical Phenomena ; Semiconductors ; *Silicon

2014-12-17

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Crystallization ; Finite Element Analysis ; Gold ; Graphite ; Lasers ; *Metal Nanoparticles ; Microscopy, Electron, Transmission ; Molecular Dynamics Simulation ; Nanotechnology/*methods ; Surface Properties

2014-05-17

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Arabidopsis/genetics/*metabolism ; Arabidopsis Proteins/genetics/*metabolism ; Cell Membrane/*metabolism ; Membrane Proteins/genetics/*metabolism ; *Protein Interaction Maps ; Signal Transduction ; Two-Hybrid System Techniques

0006-291X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

0006-291X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

1572-879X

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Abstract A novel CO conversion catalyst, Sm2Cu2/3Nb4/3O7 with a pyrochlore structure, has been synthesized. Catalytic oxidation of carbon monoxide on the catalyst can occur at about 50°C. The conversion efficiency will be close to 100% at near 300°C. Sm2Cu2/3Nb4/3O7 is an insulator. The possible effect of variation of the valence states of Sm, Cu and Nb ions in the compound on the oxidation reaction of carbon monoxide has also been discussed.

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  Mit Hilfe sowohl diskreter als auch kontinuierlicher Modellbeschreibungen wird ein dynamischer Simulationsalgorithmus für mehrgängige Kreuzstrom–Wärmeübertrager mit beliebiger Rohranzahl je Durchgang erstellt. Die Wärmekapazitäten beider Fluide und der Rohrwandelemente sowie der Wärmeleitwiderstand letzterer finden Berücksichtigung. Ein Dispersionsmodell für Pfropfenströmung ermöglicht die Ermittlung möglicherweise auftretender Ungleichmäßigkeiten der rohrseitigen Strömungsverteilung. Ferner wird die Simulationslösung auf der Basis des Pfropfenströmungsmodells ermittelt. Die zeitliche Entwicklung der Temperaturverteilung läßt sich über die Umkehroperation der Laplace-Transformation gewinnen. Abschließend werden die Ergebnisse diskutiert.

Abstract  By means of both the discrete and continuous approaches, this paper proposes dynamic simulation algorithm of multipass crossflow heat exchangers with arbitrary rows per pass. Heat capacities of both fluids and of the core wall as well as conduction resistance of the wall are taken into account. Effect of the possible tubeside flow maldistribution is described with the dispersed plug-flow model. Furthermore, the simulation solution based on the conventional plug-flow model is developed. Transient temperature profiles are obtained by numerical inversion of the Laplace transform. Some examples are calculated and discussions are made.

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 Mit Hilfe sowohl diskreter als auch kontinuierlicher Modellbeschreibungen wird ein dynamischer Simulationsalgorithmus für mehrgängige Kreuzstrom-Wärmeübertrager mit beliebiger Rohranzahl je Durchgang erstellt. Die Wärmekapazitäten beider Fluide und der Rohrwandelemente sowie der Wärmeleitwiderstand letzterer finden Berücksichtigung. Ein Dispersionsmodell für Pfropfenströmung ermöglicht die Ermittlung möglicherweise auftretender Ungleichmäßigkeiten der rohrseitigen Strömungsverteilung. Ferner wird die Simulationslösung auf der Basis des Pfropfenströmungsmodells ermittelt. Die zeitliche Entwicklung der Temperaturverteilung läßt sich über die Umkehroperation der Laplace-Transformation gewinnen. Abschließend werden die Ergebnisse diskutiert.

Abstract By means of both the discrete and continuous approaches, this paper proposes dynamic simulation algorithm of multipass crossflow heat exchangers with arbitrary rows per pass. Heat capacities of both fluids and of the core wall as well as conduction resistance of the wall are taken into account. Effect of the possible tubeside flow maldistribution is described with the dispersed plug-flow model. Furthermore, the simulation solution based on the conventional plug-flow model is developed. Transient temperature profiles are obtained by numerical inversion of the Laplace transform. Some examples are calculated and discussions are made.

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 Es wird eine Methode zur Bestimmung der Temperaturleitzahl beschrieben, die bei flüssigen und festen Stoffproben angewendet werden kann. An den Oberflächen einer flachen, ebenen Probe wird die Temperatur periodisch verändert, wodurch im Zentrum der Probe eine phasenverschobene Temperaturschwingung erzeugt wird. Beide Temperaturen werden gemessen. Die Phasenverschiebung wird zur Bestimmung der gesuchten Temperaturleitzahl verwendet. Eine besonders einfach aufgebaute Meßeinrichtung wird beschrieben. Versuchsergebnisse mit flüssigen und festen Stoffproben (Wasser, Ethanol, Heptan, Toluol, Plexiglas) zeigen gute Übereinstimmung mit bekannten Stoffdaten.

Abstract A measurement method of thermal diffusivity is described, which can be applied to fluids and solid materials. The surface temperature of a flat probe is periodically changed, so that in the center of the probe an oscillating temperature with a phase-delay is generated. Both temperatures will be measured, and the phase difference will be used for determining the thermal diffusivity of the samples. An extremely simple apparatus is shown in the paper. There is a good consistency between the measured results in this paper and existing thermal properties of the same samples: water, ethanol, heptane, toluene, plexiglass.

Electronic Resource

1435-1803

Key words Ischemic preconditioning – nitric oxide – reactive oxygen species – protein kinase C – nuclear factor kappa B – tyrosine kinase

Springer Online Journal Archives 1860-2000

Medicine

Abstract Ischemic preconditioning (PC) occurs in two phases: an early phase, which lasts 2–3 h, and a late phase, which begins 12–24 h later and lasts 3–4 days. The mechanism for the late phase of PC has been the subject of intensive investigation. We have recently proposed the “NO hypothesis of late PC”, which postulates that NO plays a prominent role both in initiating and in mediating this cardioprotective response. The purpose of this essay is to review the evidence supporting the NO hypothesis of late PC and to discuss its implications. We propose that, on day 1, a brief ischemic stress causes increased production of NO (probably via eNOS) and ·O2 –, which then react to form ONOO–, ONOO–, in turn, activates the ɛ isoform of protein kinase C (PKC); either directly or via its reactive byproducts such as ·OH. Both NO and secondary species derived from ·O2 – could also stimulate PKC ɛ independently. PKC ɛ activation triggers a complex signaling cascade that involves tyrosine kinases (among which Src and Lck appear to be involved) and probably other kinases, the transcription factor NF-κB, and most likely other as yet unknown components, resulting in increases transcription of the iNOS gene and increased iNOS activity on day 2, which is responsible for the protection during the second ischemic challenge. Tyrosine kinases also appear to be involved on day 2, possibly by modulating iNOS activity. According to this paradigm, NO plays two completely different roles in late PC: on day 1, it initiates the development of this response, whereas on day 2, it protects against myocardial ischemia. We propose that two different NOS isoforms are sequentially involved in late PC, with eNOS generating the NO that initiates the development of the PC response on day 1 and iNOS then generating the NO that protects against recurrent ischemia on day 2. The NO hypothesis of late PC puts forth a comprehensive paradigm that can explain both the initiation and the mediation of this complex phenomenon. Besides its pathophysiological implications, this hypothesis has potential clinical reverberations, since NO donors (i.e., nitrates) are widely used clinically and could be used to protect the ischemic myocardium in patients.

Electronic Resource

1573-4803

Springer Online Journal Archives 1860-2000

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

Abstract A series of new compounds with a formula RE2M2/3Nb4/3O7 (RE = Nd, Sm, Eu; M = Cu, Co, Zn) have been synthesized by a wet chemical method and the lattice parameters of the compounds have also been determined. The new compounds possess a pyrochlore structure and belong to hexagonal system. Most of the compounds have a certain catalytic activity for the oxidation reaction of carbon monoxide and propylene. The conversion efficiency of carbon monoxide and propylene on the surface of some compounds can be close to 100% at near 450°C. The compounds are insulator and the resistibility also is larger than 105 ohm · cm even if at 500°C. The compounds are a new kind of oxidation catalysts. The catalytic oxidation process of carbon monoxide and propylene on the surface of the compounds involves the oxidation-reduction of the cations in the compound and the catalytic process is a co-catalytic one. The effects of various metal cations in the compounds on the catalytic activity for the oxidation of carbon monoxide and propylene have been discussed.

Electronic Resource

0001-1541

Chemistry ; Chemical Engineering

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

Process Engineering, Biotechnology, Nutrition Technology

A versatile and efficient method is developed for predicting dynamic performances of parallel and counterflow heat exchangers subject to arbitrary temperature variations and step flow disturbances, including the effect of flow maldistribution and the influence of heat capacities of both fluids, shell wall and tube bank as well as nonzero initial temperatures. Two algorithms of numerical inversion of the Laplace transform are introduced to determine the final temperature profiles in the realtime domain and some examples are calculated with nonuniform initial conditions. The accuracy of the proposed method is demonstrated with the calculated results at new steady states. Experiments are carried out on a labor-sized heat exchanger to further examine the feasibility of this method and the comparison between calculated and measured temperature profiles is illustrated and discussed.

6 Ill.

Electronic Resource

0009-286X

Chemistry ; Polymer and Materials Science

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource