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961.
本文对羟乙芦丁在玻碳电极上的阳极微分脉冲安行为进行了研究,发现在Na2HPO4溶液中(pH=8.95)于+0.64V(vs.Ag/AgCl)左右产生一个良好的阳极氧化伏安峰,浓度在5~60mg/L之间与峰电流呈线性关系,不需分离直接测定了片剂中的羟乙芦丁含量。电极反应为扩散速率控制的不可逆可程。 相似文献
962.
本文提出一种新的拓扑指数-EA系列指数,它是从表示分子图形的邻接矩阵出发,结合图形中顶点的度构造成EA矩阵,计算EA矩阵的本征值,求出本征值绝对值和指数EAΣ及本征值绝对值最大值指数EAmax,实验表明,EA系列指数具有良好的唯一性和相关性。 相似文献
963.
N-(2-Carbomethoxy-9-methoxy-3-oxo-3H-naphtho[2,1-b]pyran-10-yl)maleimide 2 was designed and synthesized as a new maleimide fluorescent thiol reagent. The optical properties of 2 were investigated with and without the addition of glutathione, GSH. We have found 2 is twice as sensitive as DACM and is of comparable sensitivity to CPM for detection of thiols. The emission maximum for the GSH adduct of 2 is 513 nm which is at longer wavelength than the GSH adducts of both DACM and CPM. 相似文献
964.
Solutions to some practical problems that arise in multiple scattering calculations on large molecules are discussed. (1) Numerical instabilities near the zero of energy can be removed by rescaling the secular matrix. (2) The calculation of structure factors can be made much more efficient by the application of symmetry projection operators. (3) An energy search procedure is described that ensures that no states are inadvertently neglected. Test calculations incorporating these changes illustrate the improved numerical stability, and show decreases in computation time of 30–60%, when compared to previous codes. The procedures suggested here are applicable to both relativistic and nonrelatitistic calculations. 相似文献
965.
966.
The electrochemical carbon dioxide reduction reaction (CO2RR) offers a promising solution to mitigate carbon emission and at the same time generate valuable carbonaceous chemicals/fuels. Single atom catalysts (SACs) are encouraging to catalyze the electrochemical CO2RR due to the tunable electronic structure of the central metal atoms, which can regulate the adsorption energy of reactants and reaction intermediates. Moreover, SACs form a bridge between homogeneous and heterogeneous catalysts, providing an ideal platform to explore the reaction mechanism of electrochemical reactions. In this review, we first discuss the strategies for promoting the CO2RR performance, including suppression of the hydrogen evolution reaction (HER), generation of C1 products and formation of C2+ products. Then, we summarize the recent developments in regulating the structure of SACs toward the CO2RR based on the above aspects. Finally, several issues regarding the development of SACs for the CO2RR are raised and possible solutions are provided.The electrochemical carbon dioxide reduction reaction (CO2RR) offers a promising solution to mitigate carbon emission and at the same time generate valuable carbonaceous chemicals/fuels. 相似文献
967.
Xing-Zhi Liu Da-Wei Fang Jia-Zhen Yang Jun Li Shu-Liang Zang 《The Journal of chemical thermodynamics》2004,36(12):1061-1065
The equilibrium molalities In3+ in {In2(SO4)3 + Na2SO4 + HDEHMTPCA + n-C8H18 + water} were measured at ionic strength from (0.1 to 2.0) mol · kg−1 containing Na2SO4 as supporting electrolyte in aqueous phase and at constant molality extractant at temperatures from (278.15 to 303.15) K in organic phase. The standard extraction constants K0 at various temperatures were obtained by methods of extrapolation and polynomial approximation. Thermodynamic quantities for the extraction process were calculated. 相似文献
968.
POROUS MEMBRANE TEMPLATED SYNTHESIS OF POLYMER PILLARED LAYER 总被引:5,自引:0,他引:5
The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates tosynthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane pores, and thelayer on the template surfaces. Rigid cured epoxy resin, polystyrene and soft hydrogel were chosen to confirm themethodology. The pillars were in the form of either tubes or fibers, which were controlled by the alumina membrane pore surface wettability. The structural features were confirmed by scanning electron microscopy results. 相似文献
969.
Junfeng Xiao Yuan Hu Ling Yang Lei Song Weicheng Fan 《Polymer Degradation and Stability》2006,91(9):2093-2100
The fire retardant efficiency of melamine (MA) and triphenyl phosphate (TPP) in poly(butylene terephthalate) (PBT) was studied by the limiting oxygen index (LOI) and the UL94 test. On adding 10 wt. % MA and 20 wt. % TPP, LOI increased from 20.9 to 26.6 and the UL94 V-0 rating was achieved. SEM and DSC analyses show that the fire retardants are compatible with PBT and facilitate crystallization of PBT. The occurrence of an interaction between MA + TPP and PBT was elucidated by TGA, dynamic FTIR, and pyrolysis/GC/MS. MA + TPP changes the degradation path of PBT and modifies the compositions of the gas and condensed-phase products. 相似文献
970.
The first integrally oxidized metal-free phthalocyanine compounds have been synthesized by chemical oxidation. Phthalocyanine (H(2)(pc), pc = phthalocyaninato) was oxidized with IBr to afford the compounds [H(2)(pc)][IBr(2)] (1) and [H(2)(pc)](2)[IBr(2)]BrAC(10)H(7)Br (2), whose structures were determined by means of single-crystal X-ray diffraction methods: [H(2)(pc)][IBr(2)], P2(1)/c, a = 8.0272(9) A, b = 21.258(2) A, c = 18.1439(2) A, beta = 113.975(2) degrees, V = 2828.8(5) A(3), T = 153 K, Z = 4; [H(2)(pc)](2)[IBr(2)]Br.C(10)H(7)Br, P, a = 8.4724(6) A, b = 13.5794(10) A, c = 13.8403(10) A, alpha = 90.854(1) degrees, beta = 103.417(1) degrees, gamma = 97.049(1)E degrees, V = 1535.61(19) A(3), T = 153 K, Z = 1. The extended structure of [H(2)(pc)][IBr(2)] comprises slipped columns of pc rings stacked along the a axis in adjacent columns at approximately 70 degrees to one another. IBr(2-) ions occupy the interstitial columns. The extended structure of [H(2)(pc)](2)[IBr(2)]Br.C(10)H(7)Br comprises slant stacks of pc rings along the crystallographic a axis with IBr(2-) ions, Br(-) ions, and disordered 1-bromonaphthalene molecules in the adjacent, parallel columns. The overall reaction for the formation of 1 is 2H(2)(pc) + 4IBr --> 2[H(2)(pc)][IBr(2)] + I(2), and the overall reaction for the formation of 2 (not including solvent) is 2H(2)(pc) + 3IBr --> [H(2)(pc)](2)Br[IBr(2)] + I(2). 相似文献