نتایج جستجو برای: melting

تعداد نتایج: 27262  

In this study the operations of melting of Au15Ag40 nanoalloy have been studied using the molecular dynamic simulations through the Gupta multiparticle potential and the nonergodicity of simulations is eliminated by the multiple histogram method. The melting characteristics are determined by the analysis of variations in the potential energy. The calculations indicate that the melting of Au15Ag...

Journal: :Journal of the American Chemical Society 2004
Gary A Breaux Damon A Hillman Colleen M Neal Robert C Benirschke Martin F Jarrold

Calorimetry measurements (using a method based on multicollision induced dissociation) have been performed for unsupported gallium clusters, Gan+ (n = 30-50 and 55). Melting transitions have been identified from spikes in the heat capacities recorded as a function of temperature. There are enormous fluctuations in the melting temperatures and the heats of fusion with cluster size. Clusters with...

Journal: :Clinical chemistry 2005
Nicolas von Ahsen

More than 20 years after the first in vitro amplification of DNA by PCR, this technique is firmly established for diagnostic purposes in many clinical laboratories. PCR technology is an exciting field that has continually advanced. Evolutionary steps have been, for example, the transition from conventional cycling to rapid-cycling (1 ), from post-PCR to real-time product analysis (2 ), and from...

2008
Kiyoshi TAJIMA Hiroshi KAKIGAWA Yoshio KOZONO Ichiro HAYASHI

Oxygen and nitrogen introduced in three Ni-Cr alloy castings were significantly varied according to both different alloys and different melting methods. The arc melting in Ar blow caused significant increases in the amounts of oxygen and nitrogen uptake, which were influenced by alloy composition. The severe gas absorption by the arc melting in Ar blow resulted in the marked occurrence of poros...

2010

An improved technique is described for the accurate determination of melting points of metals in the temperature range 1500° to 2500°C. The improvements consist of gradient heating and refinements in cavity preparation to obtain true black-body conditions. The melting point of hafnium, as determined by this method, is set a t 22220-+30°C. This is over 200°C higher than one of the values reporte...

2009
M. Hashiya Y. Kubo W. D. Schubert

The start of melting as well as the melting range in WC-Co and WC-Ni hardmetals is significantly influenced by the alloy gross carbon content as well as by additives (V, Cr). Both Vanadium and Chromium significantly lower the start of melting but also broaden the melting range, in particular at low carbon content (formation of M6C-phases). As a result, a certain temperature range can be defined...

Journal: :Nucleic acids research 1983
V I Lyamichev I G Panyutin D I Cherny Lyubchenko YuL

Specific fragmentation of T7 DNA at glyoxal-fixed denatured regions by the S1 endonuclease followed by restriction analysis made it possible to localize four low-melting regions in phage T7 DNA. These regions have the following coordinates:0.5-1.2;14.8+/-0.3;46.3+/-0.5; 98.4+/-0.3 (in T7 DNA length units). The location of the low-melting regions was refined by means of electron-microscopic dena...

2009
Daniel Errandonea

We discus existent conflicts between experimentally measured and theoretically calculated melting curves of Mo, Ta, and W. By assuming that vacancy formation plays a fundamental role in the melting process, an explanation for the measured melting curves is provided. Furthermore, we show that the Lindemann law fits well all the measured melting curves of bcc transition metals if the Grüneisen pa...

2008
C. K. Shearer P. V. Burger

The recently recovered Antarctic achondrites Graves Nunatak 06128 and 06129 are unique meteorites that represent high-temperature asteroidal processes in the early solar system never before identified in any other meteorite. They represent products of early planetesimal melting (4564.25 ± 0.21 Ma) and subsequent metamorphism of an unsampled geochemical reservoir from an asteroid that has charac...

Journal: :Nucleic acids research 1981
B R Amirikyan A V Vologodskii Lyubchenko YuL

The paper presents measurements of the difference in the melting temperature of a colE1 DNA region when it is located inside the DNA helix and at its end. A direct comparison of calculations based on the rigorous theory of helix-coil transition with experimental data for .2 M Na+ (the conditions for fully reversible melting) yielded the value of 2.5-5x10(-5) for the cooperatively factor sigma. ...

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