The influence of hydrochloric or sulphuric acid treatment on the electro-physical properties of superthin basalt fiber (STBF) made from Armenian basalt rocks was studied. Specific electric resistance for direct and al...The influence of hydrochloric or sulphuric acid treatment on the electro-physical properties of superthin basalt fiber (STBF) made from Armenian basalt rocks was studied. Specific electric resistance for direct and alternating currents, dielectric parameters of ε, and ε,, were measured. It is shown that specific resistance and dielectric parameters of super-thin basalt fiber change essentially after hydrochloric or sulphuric acid treatment. The temperature dependences of these parameters were studied, too, and their non–monotonic behavior was observed. The probable variation of mentioned STBF parameters is explained by different water absorption capacity of pores as a result of acid treatment.展开更多
A new organic/inorganic hybrid nonlinear optical (NLO) material was developed by the sol-gel process of an alkoxysilane dye with tetraethoxysilane. A NLO moiety based on 4-nitro-4 ' -hydroxy azobenzene was covalen...A new organic/inorganic hybrid nonlinear optical (NLO) material was developed by the sol-gel process of an alkoxysilane dye with tetraethoxysilane. A NLO moiety based on 4-nitro-4 ' -hydroxy azobenzene was covalently bonded to the triethoxysilane derivative, i.e, gamma -isocyanatopropyl triethoxysilane. The preparation process and properties of the sol-gel derived NLO polymer were studied and characterized by SEM, FTIR,H-1-NMR, UV-Vis, DSC and second harmonic generation (SHG) measurement. The results indicated that the chemical bonding of the chromophores to the inorganic SiO2 networks induces low dipole alignment relaxation and preferable orientational stability. The SHG measurements also showed that the bonded polymer film containing 75 wt% of the akoxysilane dye has a high electro-optic coefficient (r(33)) of 7.1 pm/V at 1.1 mum wavelength, and exhibit good SHG stability, the r(33) values can maintain about 92.7% of its initial value at room temperature for 90 days, and can maintain about 59.3% at 100 degreesC for 300 min.展开更多
Using the first-principles method based on the density functional theory（DFT）, the work function of seven different Ga N（0001） e1 × 1T surface models is calculated. The calculation results show that the optim...Using the first-principles method based on the density functional theory（DFT）, the work function of seven different Ga N（0001） e1 × 1T surface models is calculated. The calculation results show that the optimal ratio of Cs to O for activation is between 3∶1 and 4∶1. Then, Cs/O activation and stability testing experiments on reflection-mode negative electron affinity Ga N photocathodes are performed. The surface model [Ga N（Mg）： Cs]Cs-O after being activated with cesium and oxygen is used. The experiment results illustrate that the adsorption of O contained in the residual gas increases the surface potential barrier and the reduction of the effective dipole quantity is the basic cause of the quantum efficiency decay.展开更多
文摘The influence of hydrochloric or sulphuric acid treatment on the electro-physical properties of superthin basalt fiber (STBF) made from Armenian basalt rocks was studied. Specific electric resistance for direct and alternating currents, dielectric parameters of ε, and ε,, were measured. It is shown that specific resistance and dielectric parameters of super-thin basalt fiber change essentially after hydrochloric or sulphuric acid treatment. The temperature dependences of these parameters were studied, too, and their non–monotonic behavior was observed. The probable variation of mentioned STBF parameters is explained by different water absorption capacity of pores as a result of acid treatment.
基金This work was supported by the Postdoctoral Science Foundation of Guangdong Province (No. 9644) and the Natural Science Fund of Guangdong Province(No. 990629).
文摘A new organic/inorganic hybrid nonlinear optical (NLO) material was developed by the sol-gel process of an alkoxysilane dye with tetraethoxysilane. A NLO moiety based on 4-nitro-4 ' -hydroxy azobenzene was covalently bonded to the triethoxysilane derivative, i.e, gamma -isocyanatopropyl triethoxysilane. The preparation process and properties of the sol-gel derived NLO polymer were studied and characterized by SEM, FTIR,H-1-NMR, UV-Vis, DSC and second harmonic generation (SHG) measurement. The results indicated that the chemical bonding of the chromophores to the inorganic SiO2 networks induces low dipole alignment relaxation and preferable orientational stability. The SHG measurements also showed that the bonded polymer film containing 75 wt% of the akoxysilane dye has a high electro-optic coefficient (r(33)) of 7.1 pm/V at 1.1 mum wavelength, and exhibit good SHG stability, the r(33) values can maintain about 92.7% of its initial value at room temperature for 90 days, and can maintain about 59.3% at 100 degreesC for 300 min.
基金supported by the National Natural Science Foundation of China (Nos. 61308089 and 61440065)the Public Technology Applied Research Project of Zhejiang Province (No. 2013C31068)+1 种基金the Applied Research Project of Zhejiang Provincial Education Department (Nos. Y201432598 and 201328587)the China Postdoctoral Science Foundation funded project (No. 2014M551596)
文摘Using the first-principles method based on the density functional theory（DFT）, the work function of seven different Ga N（0001） e1 × 1T surface models is calculated. The calculation results show that the optimal ratio of Cs to O for activation is between 3∶1 and 4∶1. Then, Cs/O activation and stability testing experiments on reflection-mode negative electron affinity Ga N photocathodes are performed. The surface model [Ga N（Mg）： Cs]Cs-O after being activated with cesium and oxygen is used. The experiment results illustrate that the adsorption of O contained in the residual gas increases the surface potential barrier and the reduction of the effective dipole quantity is the basic cause of the quantum efficiency decay.
