نتایج جستجو برای: c20 fullerenes
تعداد نتایج: 5000 فیلتر نتایج به سال:
The results of recent investigation of fullerenefullerene hydride system as a potential high capacity hydrogen storage option are presented. Theoretically, C60 fullerenes can reversibly store up to 7.7 wt.% hydrogen by forming fullerene hydride C60Hx. However, high temperature and pressure are currently required to enable hydrogen exchange in this system. For example, direct hydrogenation of f...
We investigate the accuracy of first-principles many-body theories at the nanoscale by comparing the low-energy excitations of the carbon fullerenes C(20), C(24), C(50), C(60), C(70), and C(80) with experiment. Properties are calculated via the GW-Bethe-Salpeter equation and diffusion quantum Monte Carlo methods. We critically compare these theories and assess their accuracy against available p...
Nonlinear optical properties in the fullerene C60 and the extracted higher fullerenes – C70, C76, C78, and C84 – are theoretically investigated by using the exciton formalism and the sum-overstates method. We find that off-resonant third order susceptibilities of higher fullerenes are a few times larger than those of C60. The magnitude of nonlinearity increases as the optical gap decreases in h...
The review examines experimental and theoretical works devoted to the description of modern methods for preparation iron endometal-fullerenes(EMF), as well that dispute such results due extremely low efficiency used methods. paper also considers advantages disadvantages synthesis, areas possible application synthesis products. It is shown EMF obtained mainly by two - arc discharge (plasma) usin...
High-level ab initio calculations have been carried out to reexamine relative stability of bowl, cage, and ring isomers of C(20) and C(20)(-). The total electronic energies of the three isomers show different energy orderings, strongly depending on the hybrid functionals selected. It is found that among three popular hybrid density-functional (DF) methods B3LYP, B3PW91, PBE1PBE, and a new hybri...
We aimed to investigate the role of serum levels of polyunsaturated fatty acid (PUFA) in the development of colorectal cancer (CRC). Serum levels of n-3 and n-6 PUFA in 69 healthy control (Ctrl), 62 benign colorectal polys (CRP) and 100 CRC patients were detected by gas chromatograph. The adjusted odds ratio (OR) by quartiles of n-3 and n-6 PUFA were analyzed. During the process of Ctrl to CRP,...
Three surprising discoveries on the nature of matter and its properties were published in the mid-1980s. All these discoveries led to Nobel prizes. The first discovery was in 1985, when fullerenes were discovered by Robert F. Curl Jr, Sir Harold W. Kroto, and Richard E. Smalley. Fullerenes, also known as buckyballs, are spherical molecules composed of carbon atoms. The discovery of fullerenes l...
How can the accuracy of the calculated standard heats of formation DeltaHf0 of fullerenes be improved? How reliable are the values of DeltaHf0 calculated from hyperhomodesmotic reactions? This work is the first to address these questions. By comparing the results obtained from three hyperhomodesmotic reactions containing only fullerenes, it is illustrated that both the resonance contribution an...
Large fullerenes and carbon-coated metal nanoparticles that are formed during the synthesis of carbon nanotubes have been functionalized by the addition of alkyl radicals and isolated by extraction into chloroform. The soluble, functionalized fullerenes have been isolated from raw single-wall carbon nanotube (SWNT) material prepared by laser oven, direct current arc, and high-pressure carbon mo...
in this study,oil was extracted from the liver and visceral fat of patin (pangasianodon hypophthalmus) and refined. the yield of oil after refining was 49.98%. the major yield loss (34.20%) happened during the degumming procedure. fatty acids found in the crude and refined oil were c12:0, c14:0, c14:1, c16:0, c16:1, c18:0, c18:1, c18:2, c18:3, c18:4, c20:0, c20:1, c20:4, c20:5, and c22:6. the d...
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