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991.
Nanoparticulate flows occur in a wide range of natural phenomena and engineering applications and, hence,have attracted much attention. The purpose of the present paper is to provide a review of the research conducted over the last decade. The research covered relates to the Brownian coagulation of monodisperse and polydisperse particles, the Taylor-series expansion method of moment, and nanoparticle distributions due to coagulation in pipe and channel flow,jet flow, and the mixing layer and in the process of flame synthesis and deposition. 相似文献
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994.
Analysis on high speed response of a uni-traveling-carrier double hetero-junction phototransistor
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In this paper, the positive influence of a uni-traveling-carrier(UTC) structure to ease the contract between the responsivity and working speed of the In P-based double hetero-junction phototransistor(DHPT) is illustrated in detail. Different results under electrical bias, optical bias or combined electrical and optical bias are analyzed for an excellent UTC-DHPT performance. The results show that when the UTC-DHPT operates at three-terminal(3T) working mode with combined electrical bias and optical bias in base, it keeps a high optical responsivity of 34.72 A/W and the highest optical transition frequency of 120 GHz. The current gain of the 3T UTC-DHPT under 1.55-μm light illuminations reaches 62 d B. This indicates that the combined base electrical bias and optical bias of 3T UTC-DHPT can make sure that the UTC-DHPT provides high optical current gain and high optical transition frequency simultaneously. 相似文献
995.
A series of thiourea-functionalised pillar[5]arene derivatives 3nm were constructed from a series of mono-amide-functionalised pillar[5]arenes 2n. The formation of their free forms or (pseudo)[1]rotaxane structures were controlled by their axle lengths or solvents, which were investigated by 1H NMR spectroscopy. Some of (pseudo)[1]rotaxane structures were also supported by their single-crystal structures. 相似文献
996.
Catalytic Performance of Carbon Materials Supported Pd Nanoparticles in Selective Hydrogenation of Acetylene
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Pd/C catalysts were prepared by deposited Pd nanoparticles (NPs) on different carbon supports including activated carbon (AC), graphite oxide (GO), and reduced graphite oxide (rGO) using sol-immobilization method. Through transmission electron microscopy, powder X-ray di raction, and X-ray photoelectron spectroscopy, the role of the carbon supports for the catalytic performances of Pd/C catalysts was examined in selective hydrogenation of acetylene. The results indicate that Pd/AC exhibited higher activity and selectivity than Pd/GO and Pd/rGO in the gas phase selective hydrogenation of acetylene. Thermal and chemical treatment of AC supports also have some effect on the catalytic performance of Pd/AC catalysts. The differences in the activity and selectivity of various Pd/C catalysts were partly attributed to the metal-support interaction. 相似文献
997.
引进了近于凸函数的新子类.利用从属关系得到了偏差定理和卷积性质.所得结果推广了一些作者的相关结果,并得到有趣的新结果. 相似文献
998.
De-Biao Huo Ji-Dong Leng Jing Wang Zi-Zhou Wang Wan-Ming Lu Xiao-Shuo Hong 《Journal of Coordination Chemistry》2017,70(5):936-948
Two mixed-valence Mn(II,IV) complexes, [MnII4MnIV3(teaH)3(tea)(thmeH)3(thme)](ClO4)2·3MeCN (1) and [MnII2MnIV2(edteH)2(peolH)2]·4MeOH (2), where H4edte = N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine, teaH3 = tris(2-hydroxyethyl)amine, H4peol = pentaerythritol, and H3thme = 1,1,1-tris(hydroxymethyl)ethane, were prepared from the corresponding manganese salts and mixed ligands with polyalcohols. The two clusters consist of a trapped-valence polynuclear core comprising 4MnII and 3MnIV for 1, 2MnII and 2MnIV ions for 2. Complex 1 crystallizes in the rhombohedral space group R3c, while 2 crystallizes in the monoclinic space group P21/c. Complex 1 consists of a near-planar Mn7 unit that comprises a Mn6 hexagon of alternating MnII and MnIV ions surrounding a central MnII ion. The remaining coordinated sites are occupied by eight different deprotonation degrees of H3tea or H3thme. The tetranuclear cluster of 2 consists of a fused defective dicubane Mn4O6 core, and the four Mn ions are coordinated by oxygens from edteH3? and peolH3? into an unusual butterfly-like [MnII2MnIV2] topology. The two clusters are also characterized by mass spectra and X-ray photoelectron spectroscopy. Direct current magnetization studies reveal ferromagnetic interactions within both Mn clusters. 相似文献
999.
建立快速溶剂萃取–高效液相色谱法测定禽蛋中磺胺嘧啶残留的方法。用单因素和正交试验对禽蛋中磺胺嘧啶的萃取条件进行优化,确定了最佳萃取条件:以甲醇为萃取剂,在130℃循环萃取4次,冲洗体积分数为80%,萃取时间为25 min。色谱柱为Hypersil ODS2柱(4.6 mm×250 mm,5μm),流动相为甲醇–0.5%冰乙酸(25∶75),流量为1.0 m L/min,检测波长为265 nm。磺胺嘧啶的质量浓度在0.025~0.500 mg/m L范围内与色谱峰面积呈良好的线性关系,相关系数r=0.999 5,检出限为0.5μg/kg。加标回收率在83.0%~88.2%之间,测定结果的相对标准偏差为2.2%(n=9)。方法的精密度、准确度和基质效应均符合禽蛋样品检测要求,可用于禽蛋中磺胺嘧啶含量的测定。 相似文献
1000.
Synthesis,Structure, and Magnetic Characterization of a Series of Iron(II) Coordination Frameworks with 2, 6‐Bis(1, 2,4‐triazole‐4‐yl)pyridine
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Yue Liu Jian Zhong Huo Yuan Yuan Liu XiuMei Su Jian Hua Guo Bin Ding Xiu Guang Wang Jun Xia 《无机化学与普通化学杂志》2015,641(14):2422-2428
Based on the bis‐triazole ligand 2, 6‐bis(1, 2,4‐triazole‐4‐yl)pyridine (L), the triazole‐iron(II) complexes [Fe(L)2(dca)2(H2O)2] · 2H2O ( 1 ) (Nadca = sodium dicyanamide), {[Fe(μ2‐L)2(H2O)2]Cl2}n ( 2 ), and {[Fe(μ2‐L)2(H2O)2](ClO4)2 · L · H2O}n ( 3 ) were isolated by solvent diffusion methods. When iron(II) salts and Nadca were used, compound 1 was isolated, which contains mononuclear Fe(L)2(dca)2(H2O)2 units. When FeCl2 or FeClO4 were used, one‐dimensional (1D) cation iron(II) chains ( 2 ) and two‐dimensional (2D) cation iron(II) networks ( 3 ) were isolated indicating anion directing structural diversity. Moreover, variable‐temperature magnetic susceptibility data of 1 – 3 were recorded in the temperature range 2–300 K. The magnetic curve of complex 2 was fitted by using the classical spin Heisenberg chain model indicating anti‐ferromagnetic interactions (J = –5.31 cm–1). Obviously complexes 1 – 3 show no detectable thermal spin crossover behaviors, the lack of spin‐crossover behavior may be correlated with FeN4O2 coordination spheres in 1 – 3 . 相似文献