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Energetic and structural stability of Al2B2H2n (n = 0—6) clusters is investigated by DFT calculations and a stochastic search algorithm. 相似文献
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Hakan Demirtas Robab Ahmadian Sema Atis Fatma Ezgi Can Ilker Ercan 《Computational Statistics》2016,31(4):1385-1401
Two algorithms for establishing a connection between correlations before and after ordinalization under a wide spectrum of nonnormal underlying bivariate distributions are developed by extending the iteratively found normal-based results via the power polynomials. These algorithms are designed to compute the polychoric correlation when the ordinal correlation is specified, and vice versa, along with the distributional properties of latent, continuous variables that are subsequently ordinalized through thresholds dictated by the marginal proportions. The method has broad applicability in the simulation and random number generation world where modeling the relationships between these correlation types is of interest. 相似文献
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Ali Sk Irsad Das Anjan Dutta Dhanadeep Das Ajit Mahata Nagendranath Mandal Samiran Mandal Atis Chandra 《Journal of Sol-Gel Science and Technology》2021,100(1):89-100
Journal of Sol-Gel Science and Technology - Nickel doped lead oxide (Pb1-xNixO) nanoparticles with different concentration (x = 0.00, 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, and 0.30) of... 相似文献
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采用密度泛函理论B3LYP与6—311++G方法研究了硼簇Bn(n=13~20)的电子和几何结构、总能量、结合能、谐波频率、点对称性、电荷分布、偶极矩、化学键以及最高分了占据轨道和最低分子占轨道能量差.此外,借助第一和第二能级差确定最稳定的硼簇尺寸.研究表明硼簇几乎所有的物理性质有尺寸依赖性,双环管状结构的B20具有最高平均结合能.内有一原子的二十面体结构的B13不具有稳定构型,这种结构转变为开放式笼状.B20出现二维到三维的结构转变.Mulliken分析表明电荷分布有x-z和y-z平面对称.硼簇的平面稳定性可以通过离域键(π键和σ键)以及多中心键来解释. 相似文献
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Density Functional Study of Physical and Chemical Properties of Nano Size Boron Clusters: Bn (n=13~20) 下载免费PDF全文
采用密度泛函理论B3LYP与6-311++G方法研究了硼簇Bn(n=13~20)的电子和几何结构、总能量、结合能、谐波频率、点对称性、电荷分布、偶极矩、化学键以及最高分子占据轨道和最低分子占轨道能量差.此外,借助第一和第二能级差确定最稳定的硼簇尺寸.研究表明硼簇几乎所有的物理性质有尺寸依赖性,双环管状结构的B20具有最高平均结合能.内有一原子的二十面体结构的B13不具有稳定构型,这种结构转变为开放式笼状.B20出现二维到三维的结构转变.Mulliken分析表明电荷分布有x-z和y-z平面对称.硼簇的平面稳定性可以通过离域键(π键和α键)以及多中心键来解释. 相似文献
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Gita Revalde Sergey Sholupov Alexander Ganeev Sergey Pogarev Vladimir Ryzhov Atis Skudra 《Analytica chimica acta》2015
A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions (196Hg, 198Hg, 202Hg, 204Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope 204Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m3 for benzene) level, the interference from SO2, NO2, O3, H2S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m3 at 1 s averaging and 0.1 mg/m3 at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. 相似文献
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