نتایج جستجو برای: critical density
تعداد نتایج: 870366 فیلتر نتایج به سال:
In this study, the superconducting properties of Bi-2223/Ag wires, made by the PIT method have been studied. Powder samples were prepared using conventional solid state reaction method. After calcination, samples with different Ag percent (0, 5, 10, 15, 20, and 25) prepared and sintered at 830 °C. It was shown that Ag addition has not only affected the formation of the desired Bi-2223 phase an...
In this paper, the effect of the cross-section on the critical current density (Jc) of a sample in ceramic superconductors YBa2Cu3O7-δ (YBCO) and Bi1.6Pb0.4Sr2Ca2cu3Oy (BPSCCO) has been studied. Five orthorhombic bar samples of YBCO with cross-sections of 6.25, 7.67, 9.25, 11.76, 14.67 mm2 and also five orthorhombic bar samples of BPSCCO with cross-section of 6.4, 9.01, 11.88, 13.86, 14.98 m...
این پژوهش با هدف مطالعه و ارزیابی ساختار الکترونی آنیونی سلول های خورشیدی در مقیاس نانو صورت گرفته است. گروهی از نانوساختارها که شامل رنگدانه های آلی عاری از فلز به کار رفته در سلول های خورشیدی حساس به رنگ(dsscs)، در نظر گرفته شده اند. این رنگدانه ها شامل واحدهای دهنده، پل و گیرنده الکترون با گروه های گیرنده مختلف می باشند. ساختار مولکولی این رنگدانه ها از لحاظ ایزومرهای ممکن در سطح b3lyp و مجم...
Twinning is one of the main mechanisms of plastic deformation in crystals and its effect on the empirical properties has been important in materials science. Twin boundaries have been proved to be effective flux pinning centers in YBCO that increasing the critical current density. High-temperature superconductor YBa2Cu3O7-x (YBCO) nanoparticles were prepared by solid state alloying method. The ...
The conformational analysis of the organic compounds specially the biologically active natural products has attracted the consideration of different research groups. Therefore, in the present study the MP2/6-311+g(d,p)//B3LYP/6-311+g(d,p) level of theory was used to study the conformations of dapdiamide D. The identity of interactions in selected conformers was studied using atom in molecule ap...
We have studied the effect of precursor powder size on the microstructure and intergranular behavior of polycrystalline Bi2223 superconductors using the XRD, SEM, electrical resistivity and AC susceptibility techniques. Polycrystalline Bi2223 superconductors were prepared from the powders with different milling times. The XRD results show that by decreasing the precursor powder size the Bi2223...
the effects of traffic frequency and skid trail slope on dry bulk density, litter mass and rutting are examined. treatments included a combination of four different traffic frequencies (3, 7, 14, and 20 passes of a rubber skidder) and three levels of slope ( 20%.) the results showed that dry bulk density, rut depth and soil displacement increased with the increase of traffic frequency and slope...
background: new blood vessels formation is a critical step in tumor progression. vascular density affects the clinical outcome and prognosis of malignant tumors. the aim of this study was to investigate the relation between the vascular endothelial growth factor (vegf) expression and vascular density with the clinical and histopathologic features in oral squamous cell carcinoma (oscc). method...
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