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991.
Yubin Xue Shun‐Chang Liu Xinsheng Liu Yusi Yang Yimin Zhang Ding‐Jiang Xue Jin‐Song Hu 《中国化学》2020,38(4):356-360
Colloidal quantum dots (CQDs) are attractive absorber materials for high‐efficiency photovoltaics because of their facile solution processing, bandgap tunability due to quantum confinement effect, and multi‐exciton generation. To date, all published performance records for PbS CQDs solar cells have been based on the conventional hot‐injection synthesis method. This method usually requires relatively strict conditions such as high temperature and the utility of expensive source material (pyrophoric bis(trimethylsilyl) sulfide (TMS‐S)), limiting the potential for large‐scale and low‐cost synthesis of PbS CQDs. Here we report a facile room‐temperature synthetic method to produce high‐quality PbS CQDs through inexpensive ionic source materials including Pb(NO3)2 and Na2S in the presence of triethanolamine (TEA) as the stabilizing ligand. The PbS CQDs were successfully prepared with an average particle size of about 5 nm. Solar cells based on the as‐synthesized PbS CQDs show a preliminary power conversion efficiency of 1.82%. This room‐temperature and low‐cost synthesis of PbS CQDs will further benefit the development of solution‐processed CQD solar cells. 相似文献
992.
Martin Proudmore Ji-Feng Ding Richard H. Mobbs Stephen G. Yeates Colin Price Colin Booth 《Journal of polymer science. Part A, Polymer chemistry》1995,33(10):1615-1625
Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc. 相似文献
993.
Shuzhen Fan Qingpu Wang Shutao Li Shuanghong Ding Fufang Su 《Optics Communications》2006,266(2):620-626
A method of more precise determination of the focal length of equivalent thermal lens (TL) is presented in this paper. The method is based on the diffraction theory of aberrations. By numerically calculating the optical path difference (OPD) distribution and the Strehl ratio, the focal lengths for “top-hat” pumping and Gaussian pumping are obtained and the equations for the focal lengths are presented by curve fitting. Also the equations for average pump radii are presented. The experiment on a fiber-coupled LD pumped Nd:YAG laser is carried out. The experimental results verify the validity of the method. 相似文献
994.
Summary An exact, three-dimensional analysis is developed for a penny-shaped crack in an infinite transversely isotropic piezoelectric
medium. The crack is assumed to be parallel to the plane of isotropy, with its faces subjected to a couple of concentrated
normal forces and a couple of point electric charges that are antisymmetric with respect to the crack plane. The fundamental
solution of a concentrated force and a point charge acting on the surface of a piezoelectric half-space is employed to derive
the integral equations for the general boundary value problem. For the above antisymmetric crack problem, complete expressions
for the elastoelectric field are obtained. A numerical calculation is finally performed to show the piezoelectric effect in
piezoelectric materials. It is noted here that the present analysis is an extension of Fabrikant's theory for elasticity.
Received 30 August 1999; accepted for publication 1 March 2000 相似文献
995.
Shi Wang Xue-Hua Ding Jing-Lin Zuo Xiao-Zeng You Wei Huang 《Coordination chemistry reviews》2011,255(15-16):1713-1732
Cyano-bridged molecule-based magnetic materials with reduced dimensionality, such as single-molecule magnets (SMMs) and single-chain magnets (SCMs), have attracted great research interest during the last decade. Among the cyano-based molecular precursors with ample coordinating capability, we note the ability of the tricyanometalate to link various metal ions lead to a wide diversity of structural architectures ranging from discrete polynuclear complexes to various one-dimensional (1D) assemblies. Some of them are promising cyano-bridged SMMs and SCMs. The use of capping tridentate organic ligands results in a number of clusters containing di-, tri-, tetra-, penta-, hexa-, octa-, fourteen-nuclear and various 1D metal-cyanide molecular architectures. Here we review the structural topologies of these complexes and their related magnetic properties, highlight typical examples, and point out the main possible directions that remain to be developed in this field. From the crystal engineering point of view, the compounds reviewed here should provide useful information for further design and investigation on this elusive class of cyano-bridged SMMs and SCMs. 相似文献
996.
Shou-Nian Ding Serge Cosnier Dan Shan Yue-Ming Sun Yao Wang 《Electrochemistry communications》2010,12(7):905-908
Elelctrogenerated chemiluminescence (ECL) of electropolymerized films based on [(2,2′-bipyridyl)(4-(2-pyrrol-1-ylethyl)-4′-methyl-2,2′-bipyridyl)2]ruthenium (II) was firstly investigated in both organic and aqueous solution. The ECL behaviors have been explained by two typical mechanisms, namely, redox-cycling type and oxidative-reduction type. For the former, no co-reactant was required and for the latter, tripropylamine (TPA) and (NH4)2C2O4 were selected as co-reactants in the organic and aqueous system, respectively. 相似文献
997.
998.
999.
Houjian Gong Guiying Xu Hui Ding Xiaofeng Shi Yebang Tan 《European Polymer Journal》2009,45(9):2540-2548
The block polyethers with various branch structure, such as TEPA[(PO)36(EO)100]7, TEPA[(PO)36(EO)100(PO)36]7, and TEPA[(PO)36(EO)100(PO)56]7 were synthesized. Moreover, the aggregation behavior was investigated via the measurements of equilibrium surface tension, dynamic surface tension, and surface dilational viscoelasticity, in order to probe the effect of the block structure on the property of the branched block polyethers. The surface tension results show that the efficiency and effectiveness of the block polyethers to lower surface tension increase with the increase of the PO group numbers. The maximum surface excess concentration (Γmax) values and the minimum occupied area per molecule at the air/water interface (Amin) values of the branched block polyethers obtained from Gibbs adsorption equations increase and decrease with the increases of the PO group numbers, respectively. The dynamic parameters n and t* representing the diffusion speed of the polyether molecules from bulky solution to the subsurface and from the subsurface to the air/water surface are obtained according to the equation proposed by Rosen. The results show that the n values firstly increase and then decrease and t* values decrease with the increase of the polyether concentrations. The results of surface dilational viscoelasticity show that the dilational modulus of TEPA[(PO)36(EO)100(PO)56]7 is the largest among the three block copolymers at the low concentration (<1 mg L−1) but that of TEPA[(PO)36(EO)100]7 is the largest at the high concentration (>1 mg L−1). 相似文献
1000.
The design of a pressurized capillary rheometer operating at prescribed temperature is described to measure the viscosity of magnetic fluids (MFs) containing Fe3O4 magnetic nanoparticles (MNPs). The equipment constant of the rheometer was obtained using liquids with predetermined viscosities. Experimentally measured viscosities were used to evaluate different equations for suspension viscosities. Deviation of measured suspension viscosities from the Einstein equation was found to be basically due to the influence of spatial distribution and aggregation of Fe3O4 MNPs. By taking account of the coating layer on MNPs and the aggregation of MNPs in MFs, a modified Einstein equation was proposed to fit the experimental data. Moreover, the influence of external magnetic field on viscosity was also taken into account. Viscosities thus predicted are in good agreement with experimental data. Temperature effect on suspension viscosity was shown experimentally to be due to the shear-thinning behavior of the MFs. 相似文献