共查询到20条相似文献,搜索用时 46 毫秒
1.
GU Shaoxuan HU Haiping TAO Haizheng ZHAO Xiujian 《武汉理工大学学报(材料科学英文版)》2005,20(4):120-122
The samples of the GeS2-Ga2 S3-CdS pseudo-ternary glassy sysem were prepared by comventional melt-quenching techniques.The microstructure of the GeS2-Ca2 S3-CdS glasses was analyzed thoroughly using Raman spectra and the relationships among the composition,microstructure and properties(such as thermal properties,densities,optical properties)were probed.The experimental results indicate that the GeS2 acts as the network former,the Ga2S3 as the net intermediate,and the CdS as the net modifier,The GeS2 and Ga2S3 exist in the form of [GeS4/2],[GaS4/2]tetrahedra or S3G3(Ga)-(Ga)GeS3 ethane-like units within the glassy network,and the addition of CdS mainly breaks the Ge(Ga)-(Ga)Ge bonds among the ethane -like units,leading to the formation of [GeS4/2].[GaS4/2]tetrahedra.The Tg and Tx have tight relations on the congregated degree of glassy network,however,λvis,n and d are hardly involved into the connectional dependence of the space arrangement. 相似文献
2.
MAO Shun TAO Haizheng ZHAO Xiujian DONG Guoping 《武汉理工大学学报(材料科学英文版)》2006,21(1):106-109
The-homogeneous GeS2-In2 S3-CsI glassy samples were prepared by conventional melt-quenching method. When the molar ratio of In2 S3 to Csl remains 1, the non-crystalline region can extend to the composition 0.4GeS2-0.3In2S3-0.3 CsI. And with the addition of CsI, the glass-forming ability of this serial glass reaches its maximum at the composition 0.8GeS2-0.1 In2 S3 -0.1CsI. According to the Raman spectra, the microstructure of these glasses is mainly constituted by [ GeS4 ] and [ InS4-xIx ] tetrahedra, which are interconnected by the bridging sulfur atoms ; meanwhile, the ethane-liked structural units [ S3 Ge-GeS3 ] can be formed because of the lacking of sulfur ; Cs ^+ ion, which is added from CsI , exists as the nearest neighbor of I-ion in the glassy network. 相似文献
3.
Room temperature EXAFS spectra of a series ofgallium phosphate glasses have been obtained in alaboratory EXAFS facility.Fourier transform isemployed for EXAFS data analysis.Low-cristobalitetype GaPO_4 crystal is used as a standard specimento extract the local structure parameters of Gaatoms in Ga_2O3-P_2O_5 glasses.The Ga-O average bondlength is 1.75-1.86 and Ga atoms can form both[GaO_4] tetrahedra and [GaO_6] octahedra in some ofthese glasses.The coordination number of Ga atomschanges from six to four with the increase of Ga_2O_3content,and this change becomes more significantwhen the Ga_2O_3 content exceeds 30mol%.The anomalouschange of the refractive index at 30mol% Ga_2O_3 iscaused by the change of the local structure of Gafrom [GaO_6] octahedra to [GaO_4] tetrahedra.A simpleformula to estimate the concentration of six foldcoordinated Ga atoms in glasses is derived based onaverage bond length measured from the EXAFS. 相似文献
4.
The effects of contents of AlF3 and Al2O3, and temperature on electrical conductivity of (Na3AlF6-40%K3AlF6)- AlF3-Al2O3 were studied by continuously varying cell censtant (CVCC) technique. The results show that the conductivities of melts increase with the increase of temperature, but by different extents. Every increasing 10 ℃ results in an increase of 1.85 × 10^-2, 1.86× 10^-2, 1.89 × 10^-2 and 2.20 × 10^-2 S/cm in conductivity for the (Na3AlF6-40%K3AlF6)-AlF3 melts containing 0%, 20%, 24%, and 30% AlF3, respectively. An increase of every 10 ℃ in temperature results an increase about 1.89× 10^-2, 1.94 × 10^-2, 1.95 × 10^-2, 1.99× 10^-2 and 2.10× 10^-2 S/cm for (Na3AlF6-40%K3AlF6)-AlF3-Al2O3 melts containing 0%, 1%, 2%, 3% and 4% Al2O3, respectively. The activation energy of conductance was calculated based on Arrhenius equation. Every increasing 1% of AlF3 results in a decrease of 0.019 and 0.020 S/cm in conductivity for (Na3AlF6-40%K3AlF6)-AlF3 melts at 900 and 1 000 ℃, respectively. Every increase of 1% Al2O3 results in a decrease of 0.07 S/cm in conductivity for (Na3AlF6-40%K3AlF6)-AlF3-Al2O3 melts. The activation energy of conductance increases with the increase in content of AlF3 and Al2O3. 相似文献
5.
(PEO)8LiClO4-SiO2 composite polymer electrolytes(CPEs) were prepared by in-situ reaction, in which ethyl-orthosilicate (TEOS) was catalyzed by HCl and NH3·H2O, respectively. The ionic conductivity, the contact angle and the morphology of inorganic particles in the CPEs were investigated by AC impedance spectra, contact angle method and TEM. The conductivities of acid-catalyzed CPE and alkali-catalyzed CPE are 2.2×10^-5 and 1.1×10^-5 S/cm respectively at 30 ℃. The results imply that the catalyst plays an important role in the structure of in-situ preparation of SiO2, and influences the surface energy and conductivity of CPE films directly. Meanwhile, the ionic conductivity is related to the surface energy. 相似文献
6.
万军鹏 《武汉理工大学学报(材料科学英文版)》2008,23(3):419-421
The IR spectra of R2O-RO-B2O3-SiO2 and R2O-RO-B2O3-Al2O3-SiO2 glasses were tested for the study of coordination state of B, Al and their content. The results show that no matter Na2O/B2O3〉1, =1, or〈1, both [BO3] and destroyed Si-O bond exist in glass structure; the addition of Al2O3 to borosilicate glass reduced both the number of non-bridging oxygen in the silicate network and the number of [BO4] units. 相似文献
7.
In this paper,the authors used the MixedCoordination EXAFS Analysis Method recentlypublished and IR to study the mixed coordination ofGe in glasses of Li_2O-ZnO-GeO_2 system,a new kindof syperionic conductor.The results show that whenthe content of ZnO is fixed,the ratio of [GeO_6]units is increased with the addition of Li_2O untilthe content of Li_2O is about 15%,and thendecreased.The relationship between the ratio of[GeO_6]and the content of Li_2O is consistent withthose between n,d of glass and Li_2O content,Therefore the germanium abnormalty can be explainedas the change of coordination number. 相似文献
8.
《武汉理工大学学报(材料科学英文版)》2016,(5)
The effect of Ga_2O_3 on the structure and properties of calcium aluminate glasses fabricated by vacuum melting process was investigated by Raman spectrum, differential scanning calorimeter(DSC), and infrared spectrum methods. The results show that calcium aluminate glass network only consists of [AlO_4] tetrahedral units. With the gradual addition of Ga_2O_3, the quantity of [GaO_4] tetrahedral units increases. Substitution of Ga_2O_3 for Al_2O_3 results in a decrease in Tg, Tx, and Tp, and an increase in the thermal stable index ΔT. Similarly, the absorption band around 3.0 μm obviously reduces and the transparency in 4.0-6.0 μm rapidly increases with increasing Ga_2O_3 content. However, the chemical stability of calcium aluminate glasses decreases if Ga_2O_3 is introduced due to the increasing of [GaO_4] units in the glass network. 相似文献
9.
殷海荣 《武汉理工大学学报(材料科学英文版)》2014,29(4):684-687
In order to increase the content of rare-earth oxides in magneto-optical glass and improve the Verdet constant, the rare-earth doped ternary Ga2O3-B2O3-SiO2(GBS) system magneto-optical glasses were prepared by the melt quenching technique. The infl uence of Tb3+ and Dy3+ ions on the structure of GBS glasses was investigated using FTIR, DSC and Faraday rotations. The experimental results showed that the content of rare-earth oxides in the glasses with the double incorporation of Tb2O3 and Dy2O3 was higher. The crystallization parameter β achieved the maximum 0.48 with Tb3+/Dy3+ content of 35mol%. Terbium oxide existed mainly in [TbO3] units in the glasses and [TbO4] units were converted into [TbO3] with increasing Tb2O3 content. As Ga3+ ion is larger than B3+ ion in radius, leading to an increasing of the glass network gap and improvement in the ability of accommodating rare earth ions, Verdet constant increased. 相似文献
10.
This study described the structural, dielectric, and piezoelectric behavior of Pb1-xSrx[(Zr0.52Ti0.48)0.95(Mn1/3Nb2/3)0.05]O3 ceramics (PSZT-PMN, x=0, 0.025, 0.050, and 0.075), prepared by a semi-wet route. X-ray diffraction, dielectric, and piezoelectric investigations were carried out to analyze the crystal structure. The relative dielectric constant and dielectric loss were both calculated as the functions of temperature. The room-temperature dielectric constant reaches a maximum for a Sr2+-modified PZT-PMN ceramic with an x value of 0.050, which corresponds to the morphotropic phase boundary (MPB). Raman spectroscopy studies also confirm the existence of this MPB for x=0.050. The piezoelectric strain coefficients (d33) value shows a maximum response for this composition. In addition, the phase transition temperature decreases significantly when the Sr2+concentration increases in the PZT-PMN ceramics. 相似文献
11.
The structural change in phase transition of hybrid (Cl2H25NH3)2MnCl4 was investigated. The temperature and the structures of the phase transition is investigated by thermal gravimetry (TG) and differential scanning calorimetry (DSC), infrared spectrum (IR) and X-ray diffraction (XRD). The results suggest that the phase transition is reversible and the structural change arises from the conformation change of the organic chain. The interlayer distance increases when the hybrid transforms from low temperature phase to high temperature phase. This is explained by the diffusion of gauche-bond along the organic chains and they move away from each other when the phase transition occurs. Combining the experimental data with theoretical calculation, we propose that organic chain of the hybrid in high temperature phase is the conformation of gauche-bond alternating with trans bond (noted as GTG'TGTG'TGTG'T). 相似文献
12.
左禹 《武汉理工大学学报(材料科学英文版)》2012,27(5):994-998
The effects of cerium nitrite on corrosion behaviors of carbon steel in simulated concrete pore solutions were studied with the methods of linear polarization, electrochemical impedance spectroscopy and surface analysis. In pore solutions in the presence of Ce(NO3)3?6H2O, the corrosion potential, polarization resistance and impedance of carbon steel obviously increased in contrast to the situation in the absence of cerium salts. The pore solution with [NO2-] / [Cl-] = 0.3 and 0.1% Ce(NO3)3?6H2O, carbon steel shows better corrosion resistance than that in the pore solution with [NO2-] / [Cl-] = 0.6, which indicates that a small amount of Ce(NO3)3?6H2O in pore solutions can effectively promote passivation of the steel and reduce the threshold [NO2-] / [Cl-] ratio for corrosion control. The surface layer formed in cerium salt containing pore solutions is more compact and smooth and 1.36%Ce is examined on the sample surface. The addition of 0.1% Ce(NO3)3?6H2O in pore solutions can decrease the corrosion rate of steel in pore solutions and has little influence on pH change of the solutions. However, more cerium nitrate addition above 0.1% may result in pH decrease of the solution. 相似文献
13.
The electrochemical behavior of CoCl2 in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6) was investigated by cyclic voltammetry. The cyclic voltammograms were obtained from electrochemical measurement under different temperatures, and the reversible behavior for Co^2+/Co^3+ redox couple on glassy carbon electrode in [bmim]PF6 was confirmed by the characteristic of the peak currents. The diffusion coefficients (about 10^-11m^2/s) of Co^2+ in [bmim]PF6 under different temperatures were evaluated from the dependence of the peak current density on the potential scan rates in cyclic voltammograms. It is found that the diffusion coefficient increases with increasing temperature. Diffusion activation energy of Co^2+ in [bmim]PF6 is also calculated to be 23.4 kJ/mol according to the relationship between diffusion coefficient and temperature. 相似文献
14.
CHEN Guorong SHI Pengfei BAI Yongping FAN Taibing 《武汉理工大学学报(材料科学英文版)》2005,20(4):104-106
An appropriate amount of toluene 2,4-diisocyanate(TDI) was added into polyether([(CH2CH2O)13 CH2O]n/Li salt electrolyte to form a cross-linked network,with improving the film proces sability and thermal stability.The relation between the structure and ioinc conductive properties of the cross-lined polyether electrolytes was investigated by means of Fourier transform infra-red spectroscopy(FTIR),differential scanning calorimetry(DSC),mechanical property and AC impedance spectroscopy.The electrolytes system is found to have two glass transitions,and it is found that the two Tgs increase with increasing salt concentration.At the some Li salt concentration,the conductivity of cross-liked polyether/LiN(CF3SO2)2 complex system is higher than that of LiClo4,At EO/Li=25:1(mol ratio),the former conductivity changes with temperature,while the later coincids with Arrhenius formula(σ=Ae^-Ea/RT).The cross-linked polyether/LiN(CF3 SO2)2 electrolyte exhibits the maximum σ=10^-4.75S/cm at 30℃. 相似文献
15.
Ayfer Kilicarslan Muhlis Nezihi Saridede Srecko Stopic Bernd Friedrich 《北京科技大学学报(英文版)》2014,(2):138-143
Brass ash from the industrial brass manufacturer in Turkey was leached using the solutions of ionic liquid (IL) 1-butyl-3-methyl-imi-dazolium hydrogen sulfate ([bmim]HSO4) at ambient pressure in the presence of hydrogen peroxide (H2O2) and potassium peroxymonosulfate (oxone) as the oxidants. Parameters affecting leaching efficiency, such as dissolution time, IL concentration, and oxidizing agent addition, were investigated. The results show that [bmim]HSO4 is an efficient IL for the brass ash leaching, providing the dissolution efficiencies of 99%for Zn and 24.82%for Cu at a concentration of 50vol%[bmim]HSO4 in the aqueous solution without any oxidant. However, more than 99%of zinc and 82%of copper are leached by the addition of 50vol%H2O2 to the [bmim]HSO4 solution. Nevertheless, the oxone does not show the promising oxidant behavior in leaching using [bmim]HSO4. 相似文献
16.
Change of Ecological Characteristics Due to Decrease of COD/SO4 ^2- Ratio During Sulfate-reduction 总被引:2,自引:0,他引:2
In order to investigate the change of ecological characteristics due to the decrease of COD/S04^2- ratio during sulfate reduction, continuous-flew tests were conducted in an acidogenic sulfate-reducing reactor with molasses wastewater as sole organic carbon source and sodium sulfate as electron acceptor, and the change of pH value, oxidation reduction potential (ORP), volatile fat acids (VFAs), alkalinity (ALK) and the predominant populations with COD/S04^2- ratio decreasing from 4. 2 to 2.0 were investigated. The experimental results demonstrated that, with decreasing COD/S04^2- ratio, ORP and ALK increased, pH value decreased, and the proportion of acetic acid in terminal products decreased significantly, and a stable -type microbial community with high COD/S04^2- ratio was converted into a sub-stable-type one with low COD/S04^2- ratio. 相似文献
17.
Cu/(10NiO-NiFe2O4) cermets containing mass fractions of Cu of 5%, 10%, 15% and 20% were prepared, and their electrical conductivities were measured at different temperatures. The effects of temperature and content of metal Cu on the electrical conductivity were investigated especially. The results indicate that the metallic phase Cu distributes evenly in 10NiO-NiFe2O4 ceramic matrix. The mechanism of electrical conductivity of Cu/(10NiO-NiFe2O4) cermets obeys the rule of electrical mechanism of semiconductor, the electrical conductivity for cermet containing 5% Cu increases from 2.70 to 20.41 S/cm with temperature increasing from 200 to 900 ℃. The change trend of electrical conductivity with temperature is similar with each other and it increases with increasing temperature and content of metal Cu. At 960 ℃, the electrical conductivity of cermet increases from 2.88 to 82.65 S/cm with the content of metal Cu increasing from 0 to 20%. 相似文献
18.
LI Yuan WU Shunhua SU Hao WANG Xiaoyong 《武汉理工大学学报(材料科学英文版)》2008,23(2):143-146
The structures and dielectric properties of Ba6-3xNd8+2xTi18O54 system(x=2/3) doped with different contents of Bi2O3, whose final molecular formula is Ba6-3x(Nd1-yBiy)8+2xTi18O54 were investigated. It is indicated that the dielectric constant increases greatly whereas Q value(f0=4 GHz) decreases with the increase of Bi2O3 content. However, the temperature coefficient could be controlled below 0±30×10^-6/℃ in the experiment. These phenomena are related to the appearance of a new phase, Bi4Ti3O12, which has high dielectric constant. Also, that Bi^3+(0.13 nm) substitutes for Nd^3+(0.099 5 nm) will increase the unit cell volume, which will lead to the enlargement of the octahedron B site occupied by Ti^4+. So the spontaneous polarization of Ti^4+ ions will be strengthened. Besides, Bi^3+ will fill up some vacancies which Ba^2+ or Nd^3+ ions leave in two A1 sites and four A2 sites. More positive ions polarize, which also contributes to higher dielectric constant. The samples got with the optimium properties are sintered at 1 200 ℃ for 4 h, when y=0.25, ε≈110, Q≈5 400(f0=4 GHz), TCC=-4.7×10^-6/℃; When y=0.3, ε≈120, Q≈5 000(f0=4 GHz), TCC=-24×10^-6/℃. 相似文献
19.
林常规 《武汉理工大学学报(材料科学英文版)》2014,29(1):9-12
A 488 nm continuous wave (CW) laser was employed in Raman spectrometer to both induce and characterize phase transformation in chalcogenide glasses. Laser-induced Raman inactive changes, structural evolution, and crystallization were observed at laser-irradiated region in GeS2-Sb2S3 glasses. The composition dependence of laser-induced phase transformation was discussed in terms of thermal stability and microstructural modification. It is strongly suggested from these results that fabrication of passive and active chalcogenide glass waveguides, such as refractive index change and nonlinear optical crystal line, is controllable by selecting appropriate glass composition, and convenient by using common CW lasers. 相似文献
20.
刘明 《武汉理工大学学报(材料科学英文版)》2013,28(6):1085-1090
The effects of various SiO2 contents on both the microstructures and properties of Ca-Ba- A1-B-Si-O glass/Al2O3 cotrtposites were investigated by FTIR, DSC, XRD and SEM. The experimental results show that increasing SiO2 content in the glass leads to the increase of [SIO4] units, increases the continuity of glass network, and decreases the trend to crystallization of composites. The shrinkage of samples rises rapid around the glass softening temperature and the final shrinkage of samples decreases with increasing SiO2 content in the glass. Borosilicate glass/Al2O3 composites with 60wt% SiO2 sintered at 875 ℃ for 15 min show better properties: a bulk density of 3.10 g,cm-3, a porosity of 0.23 %, a er value of 7.55 and a tan 8 value of 0.00053 (measured at 10 MHz) and a well matching with Ag electrodes. 相似文献