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151.
翁慧明 《浙江大学学报(理学版)》1990,17(4):385-389
本文研究用BepaiuTefta多项式逼近可微函数·改进了现有结果,建立了一个含有点态因子的渐近等式; 相似文献
152.
高功率超短超强激光脉冲的诞生开启了相对论非线性光学、高强场物理、新型激光聚变、实验室天体物理等前沿领域.近年来,随着数拍瓦级乃至更高峰值功率激光装置的建成,超强激光与等离子体相互作用进入到一个全新的高强场范畴.这种极强激光场与等离子体相互作用蕴含着丰富的物理过程,除了经典的波与粒子作用、相对论效应、有质动力效应等非线性物理过程外,量子电动力学(QED)效应变得格外重要,例如辐射阻尼效应、正负电子对产生、强伽马射线辐射、QED级联、真空极化等.本文主要介绍我们近年来在极端强激光场与等离子体相互作用中激发的QED效应以及伴随的超亮强伽马射线辐射和稠密正负电子对产生等方面的研究进展. 相似文献
153.
Shuiliang Yao Shan Weng Qi Jin Zuliang Wu Boqiong Jiang Xiujuan Tang Hao Lu Jingyi Han Yaqun Cao Xuming Zhang 《Plasma Chemistry and Plasma Processing》2017,37(1):137-148
Here, we compared the conversion of gasoline-ranged n-alkanes (C6–C9) using dielectric barrier discharge. For an energy density of ~68 J/L and an initial n-alkane concentration of ~230 ppm, when carbon number increased from 6 to 9, the energy efficiency of n-alkane conversion increased from 117 to 240 mmol/kWh, CO x selectivity decreased from 46 to 20%, and ozone concentration increased from 216 to 240 ppm. The effect of energy density and initial n-alkane concentration were also investigated. The understanding of initial step of conversion was greatly aided by a proposed kinetic model. The pathways of consecutive reactions from the initiation to products were also discussed. 相似文献
154.
Ling Y Liao TB Chen ZX Zhou YM Weng LH 《Dalton transactions (Cambridge, England : 2003)》2010,39(44):10712-10718
To systematically explore the assembly mechanism of a rutile-type open framework of {[Zn(3)(pbdc)(2)]·2H(3)O}(n) (3) (H(4)pbdc = 5-phosphonobenzene-1,3-dicarboxylic acid) constructed by 3-connected pbdc ligands and 6-connected Zn(3)(CO(2))(4)(PO(3))(2) secondary building units (Zn(3)-SBUs), three major factors including solvothermal procedures, types of solvents and amines, are taken into consideration. Seven novel structures, namely {[Zn(5)(pbdc)(2)(OH)(2)(H(2)O)(4)]·4H(2)O}(n) (1), {[Zn(3)(pbdc)(2)·H(2)O]·(Htea)·H(3)O·2-5(H(2)O)}(n) (2), {[Zn(3)(pbdc)(2)](H(3)O)(2)(dma)}(n) (4), {[Zn(2)(pbdc)(taea)]·3H(2)O}(n) (5), {[Zn(3)(pbdc)(2)(Hpda)(2)]·2H(2)O}(n) (6), {[Zn(5)(pbdc)(2)(Hpbdc)(2)]·2H(2)pz·9H(2)O}(n) (7), {[Zn(3)(pbdc)(2)]·Hpd·H(3)O·4H(2)O}(n) (8) are obtained. The results indicate that the layered-solvothermal method and the isopropanol solvent play crucial roles in the construction of the special anionic open framework of [Zn(3)(pbdc)(2)](2-). Changing these two factors led molecular assembly away from the rutile-type open framework. However, amines play a variable role in the framework, which means that by using appropriate amines, molecular assembly could generate the open framework of [Zn(3)(pbdc)(2)](2-) with pores decorated by amines. These results suggest a different approach towards decorating pores in anionic frameworks with precise structural information. 相似文献
155.
Liu R Li X Zhang H Weng L Zhou X 《Dalton transactions (Cambridge, England : 2003)》2010,39(45):11053-11059
Treatment of Cp(3)Er with one equivalent of benzimidazole-2-thiol (H(2)Bzimt) in THF affords the monoanionic HBzimt(-) complex Cp(2)Er(η(2)-HBzimt)(THF)(2) (1). Reaction of Cp(3)Yb with two equivalents of H(2)Bzimt gives complex CpYb(η(2)-HBzimt)(2)(THF) (2) at room temperature. Treatment of Cp(3)Ln with three equivalents of H(2)Bzimt in reflux THF affords the homoleptic Ln(η(2)-HBzimt)(3)(THF)(2) (Ln = Er (3), Y (4)). Cp(3)Ln reacts with 0.5 equivalents of H(2)Bzimt to afford the dianionic Bzimt(2-) complexes [(Cp(2)Ln)(THF)](2)(μ-Bzimt) (Ln = Yb (5), Er (6), Dy (7), Y (8)) in good yields, in which the Bzimt(2-) ligand bridges the two metals in an μ-η(2):η(2) coordination mode. Interestingly, controlled hydrolysis of complexes Cp(2)Ln(η(2)-HBzimt)(THF)(2), CpLn(η(2)-HBzimt)(2)(THF) and [(Cp(2)Ln)(THF)](2)(μ-Bzimt) produces the same tetranuclear complexes [CpLn(μ(3)-OH)(μ-η(1):η(2)-HBzimt)](4) (Ln = Yb (9), Er (10), Y (11)), indicating that the hydrolysis selectivity greatly depends on the number of coordinated cyclopentadienyl groups. All complexes were characterized by elemental analysis, spectroscopic properties and X-ray single crystal diffraction analysis. 相似文献
156.
Limin Han Guangbin Zhang Ning Zhu Ruijun Xie Quanling Suo Meihua Luo Linhong Weng 《Journal of Cluster Science》2010,21(4):789-801
Two novel bimetallic complexes, [Cr(CO)3(η
6-C6H5)–C≡C–C6H4–Fc] (Fc = C5H5FeC5H4] (1) and [Cr(CO)3(η
6-C6H5)–C ≡ C–Fc–C(CH3)2–Fc] (3), were synthesized by the Sonogashira coupling reaction. By using of (1) and (3) as ligands to react with Co2(CO)8, two others novel polymetallic complexes, [Cr(CO)3(η
6-C6H5){Co2(CO)6-η
2-μ
2-C≡C–}–C6H4–Fc] (2) and [Cr(CO)3(η
6-C6H5){Co2(CO)6-η
2-μ
2-C≡C–}Fc–C(CH3)2–Fc] (4) were obtained. Four carbonyl complexes were characterized by elemental analysis, FT-IR, NMR and MS. The molecular structures
of complexes (1), (2) and (4) were determined by single crystal X-ray diffraction. The interactions among the ferrocenyl,
Cr(CO)3 and Co2(CO)6-η
2-μ
2-C≡C– units were investigated by cyclic voltammetry. 相似文献
157.
Guang‐Hui Zhao Juan Li Rui‐Qing Lin Feng‐Cai Zou Wei Liu Zi‐Guo Yuan Xi‐Hao Mo Hui‐Qun Song Ya‐Biao Weng Xing‐Quan Zhu 《Electrophoresis》2010,31(4):641-647
In the present study, restriction site‐amplified polymorphism (RSAP) markers were used to examine the genetic variability of Schistosoma japonicum isolates from different endemic provinces in mainland China. Of the 45 pairs of primers screened, 10 RSAP markers showed a clear banding pattern with good resolution; however, only six exhibited a polymorphism among different isolates. Among six RSAP markers, one pair of primers (R8+R10) was able to differentiate male and female parasites, and amplified one constant specific band for female S. japonicum isolates. The specific band was recovered, re‐amplified and sequenced, and a sequence of 162 bp was obtained. Based on this sequence, a pair of specific primers was designed and used to develop sequence characterized amplified region (SCAR)‐PCR assay for identification and differentiation of female S. japonicum isolates. The SCAR‐PCR assay allowed the specific identification of female S. japonicum, with no amplicons being amplified from male S. japonicum, Fasciola hepatica, Clonorchis sinensis, S. mansoni (male and female parasite). DNA sequencing confirmed the identity of the amplified products. The minimum amount of DNA detectable using SCAR‐PCR assay was 0.3 ng for female S. japonicum. The SCAR‐PCR was able to differentiate effectively the male and female S. japonicum worms collected from 12 geographical origins in eight endemic provinces, the gender of which was known based on the morphological and biological features. These results showed that SCAR‐PCR provides an effective tool for the sex differentiation studies of S. japonicum, identification of female S. japonicum, diagnosis and epidemiological survey of S. japonicum infections in animals and human. 相似文献
158.
The boron atom in C22H15BO5 is O,O’-chelated by the anions in a tetrahedral geometry, with the planar five-and six-membered chelate rings being orthogonal to each other. The molecule lies on a two-fold rotation axis. The molecule is disordered with respect to another molecule in a 93:7 ratio; the treatment of the ‘whole-molecule disorder’ by employing a large number of restraints is described. Crystal data: C22H15BO5, monoclinic C2/c, a = 17.1804(5), b = 12.9409(4), c = 9.8842(3) , β = 124.832(2)o, V = 1803.82(9) 3 at –173 K. 相似文献
159.
Syntheses,Structural Characterization and Thermoanalysis of Transition-Metal Compounds Derived from 3,5-Dinitropyridone 总被引:1,自引:0,他引:1
Rong Fan Qiu-Ping Zhou Guo-Fang Zhang Mei-Yu Cai Ping Li Li-Hua Gan Feng-Qi Zhao Ji-Zhen Li Xue-Zhong Fan Seik Weng Ng 《Journal of chemical crystallography》2010,40(3):266-271
Abstract
Nine metal compounds of Mn(II), Zn(II) and Cd(II) derived from dinitropyridone ligands (3,5-dinitropyrid-2-one, 2HDNP; 3,5-dinitropyrid-4-one, 4HDNP and 3,5-dinitropyrid-4-one-N- hydroxide, 4HDNPO) were characterized by elemental analysis, FT-IR and partly by TG-DSC. Three of which were further structurally characterized by X-ray single-crystal diffraction analysis. The structures of the three compounds, Mn(4DNP)2(H2O)4, 4, Zn(4DNPO)2(H2O)4, 8, and Cd(4DNPO)2(H2O)4, 9, crystallize in the monoclinic space group P2(1)/n and Z = 2, with a = 8.9281(9), b = 9.1053(9), c = 10.6881(11) Å, β = 97.9840(10)° for 4; a = 8.4154(7), b = 9.9806(8), c = 10.5695(8) Å, β = 97.3500(10)° for 8; a = 8.5072(7), b = 10.2254(8), c = 10.5075(8) Å, β = 96.6500(10)° for 9. All three complexes are octahedral consisting of four equatorial water molecules, and two nitrogen or oxygen donor ligands (DNP or DNPO). The abundant hydrogen-bonding and π-π stacking interactions seem to contribute to stabilization of the crystal structures of the compounds. The TG-DTG results revealed that the complexes showed a weight loss sequence corresponding to all coordinated water molecules, nitro groups, the breaking of the pyridine rings and finally the formation of metal oxides. 相似文献160.