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61.
对于NO分子轨道的能级次序现有两种不同的说法,不少人根据NO与O_2~+是等电子体,由O_2~+分子的能级次序确定NO分子组态。本文用NO和O_2~(+)从头计算结果以及NO的紫外光电子能谱相结合的方法说明NO的5σ轨道是弱成键轨道,5σ的轨道能稍高于1π轨道能,也就是说NO的能级次序是与N_2分子相同的;NO与O_2~+虽是等电子体,但是能级次序并不相同,因此由O_2~+的能级次序确定NO分子的电子组态是不妥的。 相似文献
62.
Summary Retention indices and their energy equivalents were determined for ten alkylthiazoles analysed on the stationary phases Apiezon
L, Triton X-305 and Carbowax 1000. It was found that the energy contributions of identical alkyl groups to the partial molar
free energy of sorption of a molecule are not equivalent. Smaller energy contribututions are due to the α-position of alkyl
groups with respect to the heteroatoms in the thiazole ring (α-effect). This effect was most pronounced for 2-alkylthiazoles.
Higher sorption energies were found for dimethylthiazoles with two methylgroups in a vicinal position. The retention indices
were predicted for ten other di- and tri-substituted methyl, ethyl and propyl thiazoles on the basis of the so-called α- and
ortho-effects. The predicted values are in good agreement with the experimentally determined values.
Dedicated to Prof. Dr. E. sz. Kováts (Ecole Polytechnique Fédérale de Lausanne) on the occasion of his sixtieth birthday. 相似文献
63.
《无机化学与普通化学杂志》2018,644(16):893-900
Sr8MgCe(PO4)7:Eu2+,Mn2+ phosphor with whitlockite‐type structure was prepared by a combustion‐assisted solid‐state reaction. The crystal structure and luminescence properties were investigated. Under UV radiation, Sr8MgCe(PO4)7 host exhibits a violet‐blue emission band from Ce3+ ions. When Eu2+/Mn2+ are doped into the host, the samples excited with 270 nm UV radiation present multicolor emissions due to the energy transfer (ET) from Ce3+ to Eu2+/Mn2+. The emitting color of Sr8MgCe(PO4)7:Eu2+ can be tuned from violet‐blue to yellow‐green, whereas Sr8MgCe(PO4)7:Mn2+ can emit red light. Under excitation with long wavelength at 360 nm, Sr8MgCe(PO4)7:Eu2+ phosphor shows a broadband emission from 390 to 700 nm, which is attributed to the 4f65d1→4f7 transition of Eu2+ without the contribution from Ce3+ emission. Tunable full‐color emitting light can be achieved in the Eu2+ and Mn2+‐codoped Sr8MgCe(PO4)7 phosphor by ETEu–Mn through control of the levels of doped Eu2+ and Mn2+ ions. These results suggest that Sr8MgCe(PO4)7:Eu2+,Mn2+ phosphor has potential applications in NUV chip pumped white LEDs. 相似文献
64.
Xiqiang Zhao Jian ZhangZhanlong Song Hongzhen LiuLongzhi Li Chunyuan Ma 《Journal of Analytical and Applied Pyrolysis》2011,92(1):43-49
The compressed wheat and corn straw bale were pyrolyzed on a microwave heating device self-designed and built with respect to the time-resolved temperature distribution, mass loss and product properties. Considering scale up and technology promotion of microwave pyrolysis (MWP), the investigations on electricity consumption and energy balance of MWP were carried out emphatically. The results indicated that MWP had obvious advantages over conventional pyrolysis, such as heating rapid and more valuable products obtained. The distribution of pyrolysis products such as gas, liquid and char was close to 1:1:1 due to the medium pyrolysis temperature and the slow heating rate, which was not favorable for the formation of gas and/or liquid products. The content of H2 attained the highest value of 35 vol.% and syngas (H2 and CO) was greater than 50 vol.%. The electricity consumption of MWP was between 0.58 and 0.65 kW h (kg straw)−1 and with the increase of microwave power, the electricity consumption required for pyrolysis of unit mass of straw increased. The minimum microwave power for MWP was about 0.371 kW (kg straw)−1 and the proportion of heat loss and conversion loss of electricity to microwave energy occupied in the total input energy was 42%. Data and information obtained are useful for the design and operation of pyrolysis of large-sized biomass via microwave heating technology. 相似文献
65.
已有研究表明,中国地区大气0℃层的高度自20世纪70年代以来上升了200m左右,本文应用大气绝热模型简单分析了0℃层上升的可能原因. 相似文献
66.
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68.
Interlayer energy transfer between 2,3-naphthol-10-hexadecylaza-15-crown-5(NC16) and N-[1-(9-methoxyanthryl)] decylaza-15-crown-5(A10C) within multilayer Langmuir-Blodgett films has been studied by steady-state fluorescence spectra. The donor and acceptor could be separated precisely by inserting stearic acid (SA) spacers. The efficiency of the energy transfer increases with the decrease in the donor-acceptor distance by a quadratic manner, suggesting the donor excitations are delocalized in the layer. 相似文献
69.
Dale Newbury David Wollman Sae Woo Nam Gene Hilton Kent Irwin John Small John Martinis 《Mikrochimica acta》2002,138(3-4):265-274
Analytical X-ray spectrometry for electron beam instruments has advanced significantly with the development of the microcalorimeter
energy dispersive X-ray spectrometer (μcal EDS). The μcal EDS operates by measuring the temperature rise when a single photon
is absorbed in a metal target. A cryoelectronic circuit with electrothermal feedback and a superconducting transition edge
sensor serves as the thermometer. Spectral resolution approaching 4.5 eV for high energy photons (6000 eV) and 2 eV for low
energy photons below 2000 eV has been demonstrated in energy dispersive operation across a photon energy range from 250 eV
to 8 keV. Spectra of a variety of materials demonstrate the power of the μcal EDS to solve practical problems while operating
on a scanning electron microscope platform. 相似文献
70.
Natural cellulose substances have been proven to be ideal structural templates and scaffolds for the fabrication of artificial functional materials with designed structures, psychochemical properties and functionalities. They possess unique hierarchically porous network structures with flexible, biocompatible, and environmental characteristics, exhibiting great potentials in the preparation of energy-related materials. This minireview summarizes natural cellulose-based materials that are used in batteries, supercapacitors, photocatalytic hydrogen generation, photoelectrochemical cells, and solar cells. When natural cellulose substances are employed as the structural template or carbon sources of energy materials, the three-dimensional porous interwoven structures are perfectly replicated, leading to the enhanced performances of the resultant materials. Benefiting from the mechanical strengths of natural cellulose substances, wearable, portable, free-standing, and flexible materials for energy storage and conversion are easily obtained by using natural cellulose substances as the substrates. 相似文献