نتایج جستجو برای: geochemical calculations
تعداد نتایج: 123646 فیلتر نتایج به سال:
در این تحقیق ? کنفورماسیون های دی پپتیدhco–l-ser-l-ala–nh2و hco–d-ser-d-ala–nh2که در پروتئین های متعددی وجود دارد ? در فاز گازی مورد بررسی قرار گرفته است. محاسبات با استفاده از برنامه گوسین 3 و با بهره گیری از سطح تئوری g*31-6b3lyp/انجام شده است. بدین صورت که ابتدا ساختارهای بهینه و انرژی برای کنفورماسیون های حاصل از چرخش زاویه (c) به فواصل30 درجه از صفر درجه تا 360 درجه محاسبه شدند که سه مین...
the structural and energetic characteristics of o3–h2o complexes have been investigated by means of b3lyp, mp2, mp4(sdtq), ccsd(t) and qcisd(t) methods in conjunction with the aug-cc-pvdz and aug-cc-pvtz basis sets. six conformers were found for the o3–h2o complex. two different intermolecular interactions were expected to participate in the formation of complexes, namely conventional o∙∙∙h hyd...
an ab initio and density functional theory (dft) study about conformational analysis of tripeptide model hco−gly−l−ile−gly−nh2 is presented. the tripeptide was scanned about initial, central, and final residues, separately while for every scanning procedure the two other residues had been kept in the β conformation and side chain (sc) dihedral angles were maintained on the gauche− (g‾) state (χ...
ab initio calculations at hf/6-31g* level of theory for geometry optimization and mp2/6-31g*//hf/6-31g*for total energy calculation are reported for z-cyclooctene (1). the most favorable conformation of 1 is theunsymmetric boat-chair (1-bc) geometry. potential energy profiles for two different boat-chair/boat-chairinterconversion processes were calculated. the process via a chair transition sta...
the thermodynamic functions such as enthalpy (h), gibbs free energy (g) and entropy (s) of serineand threonine amino acids were theoretically studied at different condition (solvents andtemperatures) by using gussian o3, software. first, the structural optimization of isolated serine andthreonine were done in the gas phase by using the hartree-fock (hf) level of theory with 3-21g, 6-31g and 6-3...
Hanza region is located in the southern part of Urumieh–Dokhtar Metallogenic belt in southeastern Iran. This region includes six known porphyry copper deposits and it is considered as an ore- bearing region from geochemical point of view. The aim of this research is to examine effective processing techniques in the analysis of stream sediment geochemical datasets and ASTER satellite images. The...
in an attempt to reconstruct the paleoenvironments of deposition for the middle jurassic baghamshah formation, samples collected from six outcrop sections along the shotori swell were subjected to detailed geochemical analyses. bulk geochemical and biological marker data indicate a logical trend of the variation of organic input, salinity, and oxicity within baghamshah paleoenvironments across ...
Detection of deep and hidden mineralization using the surface geochemical data is a challenging subject in the mineral exploration. In this work, a novel scenario based on the spectrum–area fractal analysis (SAFA) and the principal component analysis (PCA) has been applied to distinguish and delineate the blind and deep Mo anomaly in the Dalli Cu–Au porphyry mineralization area. The Dalli miner...
Eocene volcanic rocks in south of Asad Abad (north-east of Koohpayeh, Isfahan Province) experienced very low-grade metamorphism (hydrothermal metamorphism), resulting in prehnite, malachite, azurite, zeolite, quartz and calcite crystallization in cavities and fractures. Chlorite (brunsvigite) and amphibole (ferro-actinolite) appear on secondary phases. Augite and labradorite are two main minera...
[1] Although most Central American magmas have a typical arc geochemical signature, magmas in southern Central America (central Costa Rica and Panama) have isotopic and trace element compositions with an ocean island basalt (OIB) affinity, similar to the Galapagos-OIB lavas (e.g., Ba/La < 40, La/Yb > 10, Pb/Pb > 18.8). Our new data for Costa Rica suggest that this signature, unusual for a conve...
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