نتایج جستجو برای: positive temperature coefficient

تعداد نتایج: 1233903  

Journal: :The journal of physical chemistry. B 2006
Hui Ning Rio Kita Hartmut Kriegs Jutta Luettmer-Strathmann Simone Wiegand

We studied the thermal diffusion behavior of hexaethylene glycol monododecyl ether (C12E6) in water by means of thermal diffusion forced Rayleigh scattering (TDFRS) and determined Soret coefficients, thermal diffusion coefficients, and diffusion constants at different temperatures and concentrations. At low surfactant concentrations, the measured Soret coefficient is positive, which implies tha...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان 1389

run-out-table (rot) is located between last finishing stand and down coiler in a hot strip mill. as the hot steel strip passes from rot, water jets impact on it from top and bottom and strip temperature decreases approximately from 800-950 °c to 500-750°c. the temperature history that strip experience while passing through rot affects significantly the metallurgical and mechanical properties, s...

2005
M. Olzmann

were studied in a quasi-static reaction cell in the temperature range 293 ≤ T/K ≤ 501 at a pressure of 10 mbar and 20 mbar, respectively, with He as the main carrier gas. The electronically excited reactant NH(a) was generated by laser-flash photolysis of HN3, at λ= 308 nm and detected by laser-induced fluorescence (LIF). Also the ground state species NH(X) was detected by LIF. From the measure...

Journal: :نشریه دانشکده فنی 0
زین الدین نجات

the volumetric expansion coefficient has an importance in determination of the free convection heat transfer coefficient. the buoyant force in the fluid which is the result of the variation of fluid density with temperature, is proportional to this expansion coefficient, b. this coefficient of b varies with temperature and it is important to understand under what conditions it should be evaluat...

1999
J. R. Gao J. P. Heida B. J. van Wees M. Klapwijk

We measure low temperature current transport properties of superconducting Sn contacts to pf-GaAs. For contacts alloyed at 450 C, the current-voltage characteristics show a strong dependence on alloying time. The critical temperature of Sn near the superconductor-semiconductor interface decreases from 3.8 to 1.8 K as the alloying time increases from 0 to 120 s. On the other hand, a long-time al...

Journal: :Nano letters 2012
Jonathan R Widawsky Pierre Darancet Jeffrey B Neaton Latha Venkataraman

We report the first concurrent determination of conductance (G) and thermopower (S) of single-molecule junctions via direct measurement of electrical and thermoelectric currents using a scanning tunneling microscope-based break-junction technique. We explore several amine-Au and pyridine-Au linked molecules that are predicted to conduct through either the highest occupied molecular orbital (HOM...

2012
D. I. Bradley S. N. Fisher A. M. Guénault R. P. Haley Mukesh Kumar C. R. Lawson Roch Schanen P. V. E. McClintock Lydia Munday G. R. Pickett Malcolm Poole V. Tsepelin Paul Williams

Wepresentmeasurements of the dissipative turbulent drag on a vibrating grid in superfluid 4He over awide range of (low) frequencies. At high velocities, the dissipative drag is independent of frequency and is approximately the same as that measured in normal liquid 4He. We present measurements on a similar grid in superfluid 3He-B at low temperatures which shows an almost identical turbulent dr...

2002
Ryszard Romaniuk Jan Dorosz

We report the theoretical and experimental study of a temperature sensor based on the changing of the refractive index with the temperature in double core optical fibre. Because of it the coupling coefficient between two cores depends on temperature. This sensor uses the double core fibre directly as a temperature sensor as well to a data transmission. The influence of variations of the tempera...

2003
SELIG HECHT

1. The determination of the influence of temperature on the velocity of a photochemical reaction is always of importance. This is particularly true when the mechanism of the reaction is unknown, as in the present instance of the bleaching of visual purple. The usefulness of determining the temperature coefficient lles in this. Photochemical reactions have low temperature coefficients.near unity...

2003
Selig Hecht

1. The determination of the influence of temperature on the velocity of a photochemical reaction is always of importance. This is particularly true when the mechanism of the reaction is unknown, as in the present instance of the bleaching of visual purple. The usefulness of determining the temperature coefficient lles in this. Photochemical reactions have low temperature coefficients.near unity...

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