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61.
基于修正的Van-Vleck Weisskopf线型、辐射传输色散理论和水汽连续体吸收模型,结合HITRAN数据库,建立了太赫兹波大气传输衰减模型VVWH,形成了对宽频太赫兹波在真实大气中水平传输衰减的数值模拟能力。同时对太赫兹时域光谱技术(THz-TDS)获取的透射光谱实测数据进行了对比分析。计算结果与实验结果总体变化趋势一致,在吸收谱线处两者吻合良好,但在低频的大气窗口区,实验结果相比计算呈现出更强的传输衰减。考察了相对湿度对太赫兹波大气传输衰减特性的影响变化。 相似文献
62.
<正>聚芳醚(PAEs)具有优异的热稳定性和力学强度,已在航空航天、汽车和生物材料等获领域得了重要应用~([1,2]).将具有一定作用的功能性基团,如—F,—SO3H和—C≡CH等,引入到PAEs分子链中使这类材料获得特殊的性能是高性能高分子材料研究领域的重要课题~([3~5]).以Teflon~和Nafion~为代表的含氟聚合物在不粘涂层、燃料电池用质子交换膜和高效气体分离~([6~8]) 相似文献
63.
Hanyu Li Zhengping Zhang Tomokazu Iyoda Meiling Dou Feng Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(22):5768-5776
An ice/salt-assisted strategy has been developed to achieve the green and efficient synthesis of ultrathin two-dimensional (2D) micro/mesoporous carbon nanosheets (CNS) with the dominant active moieties of Fe−N4 (Fe-N-CNS) as high-performance electrocatalysts for the oxygen reduction reaction (ORR). The strategy involves freeze-drying a mixture of iron porphyrin and KCl salt using ice as template followed by a confined pyrolysis with KCl as an independent sealed nanoreactor to facilitate the formation of 2D carbon nanosheets, N incorporation, and porosity creation. The well-defined assembly of ultrathin 2D carbon nanosheets ensures high utilization of D1 and D3 Fe−N4 active sites, and effectively promotes the mass transport of ORR reactants by virtue of the pronounced mesoporous structure. The resulting Fe-N-CNS electrocatalyst was shown to exhibit superior ORR activity, better electrochemical durability, and methanol tolerance towards ORR in alkaline electrolyte relative to the commercial Pt/C electrocatalyst. 相似文献
64.
Qing Huang Hanyu Qian Dong Feng Yao Wang Nan Luo Suya Lu Qingshui Shi Mei Zhang Yihong Lu Li Tan 《Journal of separation science》2020,43(11):2042-2052
The current quality control methods relying mainly on chromogenic reaction can hardly ensure the quality and safety of the biochemical drug with complex chemical composition. Therefore, a chromatographic fingerprint method was developed for the quality evaluation of a multicomponent biochemical drug, transfer factor injection. High‐performance liquid chromatography fingerprint was measured by using a C18 column (250 × 4.6 mm, 5 µm) with a mobile phase composed of 0.1% trifluoroacetic acid–water and 0.085% trifluoroacetic acid–acetonitrile under gradient elution. The developed method was validated and was subsequently applied to 57 batches of commercial products which were sampled by National Drug Assessment Program. High‐resolution mass spectrometry analysis was performed on characteristic peaks of fingerprints, and a series of amino acids, nucleosides, and deoxynucleosides were identified. In the fingerprint assessments, principal component analysis and Hotelling T2 analysis yielded the best results. The results generally indicated that there was a significant difference among products of batch‐to‐batch or from different manufacturers. Abnormal samples and its discriminatory components were also explored. In summary, the established fingerprinting method with multivariate statistical analysis could offer an efficient, reliable, and practical approach for quality consistency evaluation of transfer factor injection, providing a reference for the quality control of other multicomponent biochemical drugs. 相似文献
65.
Yuan Liu Xue Li Qinghua Zhang Weidong Li Yu Xie Hanyu Liu Lu Shang Zhongyi Liu Zhimin Chen Lin Gu Zhiyong Tang Tierui Zhang Siyu Lu 《Angewandte Chemie (International ed. in English)》2020,59(4):1718-1726
A challenging but pressing task to design and synthesize novel, efficient, and robust pH‐universal hydrogen evolution reaction (HER) electrocatalysts for scalable and sustainable hydrogen production through electrochemical water splitting. Herein, we report a facile method to prepare an efficient and robust Ru‐M (M=Ni, Mn, Cu) bimetal nanoparticle and carbon quantum dot hybrid (RuM/CQDs) for pH‐universal HER. The RuNi/CQDs catalysts exhibit outstanding HER performance at all pH levels. The unexpected low overpotentials of 13, 58, and 18 mV shown by RuNi/CQDs allow a current density of 10 mA cm?2 in 1 m KOH, 0.5 m H2SO4, and 1 m PBS, respectively, for Ru loading at 5.93 μgRu cm?2. This performance is among the best catalytic activities reported for any platinum‐free electrocatalyst. Theoretical studies reveal that Ni doping results in a moderate weakening of the hydrogen bonding energy of nearby surface Ru atoms, which plays a critical role in improving the HER activity. 相似文献
66.
67.
In this paper, the perturbation analysis for the symplectic QR factorization is considered. Some first-order and rigorous normwise perturbation bounds with normwise or componentwise perturbations in the given matrix are presented. 相似文献
68.
In this note, we consider the perturbation analysis for the generalized Cholesky factorization further. The conditions for the main theorems of the paper [W.-G. Wang, J.-X. Zhao, Perturbation analysis for the generalized Cholesky factorization, Appl. Math. Comput. 147 (2004) 601-606] are weakened by using an alternative method. Moreover, some new perturbation bounds are also derived. 相似文献
69.
Siyu Lu Wei Ma Gan Jin Qingsen Zeng Xiaolei Feng Tanglue Feng Hanyu Liu Sheng Meng Simon A. T. Redfern Bai Yang 《中国科学:化学(英文版)》2018,61(4):437-443
As a route to improving the energy conversion of organic-inorganic hybrid-solar cells, we have tested the performance of poly (phenylene vinylene) (PPV), poly(2,5-thienylene vinylene) (PWTV) polymers and CdTe nanocrystal devices produced via aqueous-processing. It is found that small differences in the conformation of the sensitizer lead to dramatic effects on the solar cell efficiency. Using a combination of UV-Vis absorption spectroscopy and first-principles non-adiabatic molecular dynamics (NAMD) based on time-dependent density-functional theory (TDDFT), PPV is found to have a longer electron injection and recombination time despite seeming to have a better energy alignment with the substrate, which leads to a higher devices performance than PWTV. The present results shed new light on the understanding of organic-inorganic hybrid-solar cells and will trigger further experimental and theoretical investigations. 相似文献
70.
Wataru Ando Yukio Hanyu Toshikazu Takata Tosio Sakurai Kimiko Kobayashi 《Tetrahedron letters》1984,25(14):1483-1486
Photooxidation of thiiranoradialene sulfoxide afforded a new thiirene sulfoxide fused with an endoperoxide ring, which gave the [2+4]cycloadduct with furan. 相似文献