Papers by Author: Di Wang

Abstract: Three kinds of TiO2 materials named Ti0, Ti0.5 and Ti1.0 were prepared via hydrothermal synthesis method using Tetrabutyl titanate (TNB) as the material and different amounts of Gemini Surfactant we prepared as the template. Then the prepared TiO2 nanoparticle was characterized by Scanning electron microscope(SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Taking the UV light as the light source ,the photocatalytic activity of TiO2 to rhB was studyed . The results showed that the degradation rate of Ti0, Ti0.5 ,Ti1.0 to RhB respectively was 93.6 % , 93.9 %, 99.7 % at the time of 3 hours. The catalytic activity of Ti0.5 and Ti1.0 was obviously better than Ti0, what’s more, Ti1.0 almost made RhB completely degradated at the time of 3 hours.

Abstract: Conventional pesticide applications repeatedly failed to adequately control mosquito and sandfly populations in desert areas, due to effects of intense heat, blowing sand, ultraviolet light and/or combinations of them under severe environmental conditions. The citronellal was copolymerized with vinyl-POSS to enhance the resistant to ultraviolet radiation and thermal stability. The polymerization process between vinyl-POSS and citronellal were simulated by using Dmol³ program of MS software based on DFT. The calculation results showed that the double bonds in vinyl-POSS were initiated easily by phenyl radical, at the same time some double bonds in citronellal were also initiated. After the initiation process, the copolymerization between vinyl-POSS initiated by phenyl radical and citronellal was firstly processed. When the double bonds in vinyl-POSS were run out, the self-polymerizations of citronellal were processed.

Abstract: Polymorphic structure of polyhedral oligomeric silsesquioxanes (POSS) derived from hydrolytic condensation of vinyltrimethoxysilane was validated by the spectral characterization, such as FTIR, UV-MALDI-TOF MS, etc. Discover module of Materials Stutio (MS) software which is a molecular dynamic simulations (MDS) program has been used to estimate the self-diffusion coefficients of small gas molecules in models of hybrid materials that validates the corresponding anticorrosion-experiment results. The models of 3D-amorphous cubic unit cells of different numbers of Si atom and hydroxyls generated during the hydrolytic condensation (T₆, T₇, T₈, T₉, T₁₀, T₈(OH)₂ and T₈(OH)₄ cells), were employed to investigate self-diffusion coefficients by MDS for the N₂, O₂, Cl₂, CO₂, NO₂, SO₂ and H₂O molecules. The simulations results showed that all seven self-diffusion coefficients of N₂, O₂, Cl₂, CO₂, NO₂, SO₂ and H₂O in cells increased with the numbers of Si atoms and the generated hydroxyls. This increasing was discussed by the calculation, compared to the vinyltrimethoxysilane hybrid systems.

Abstract: Polymorphic structure of polyhedral oligomeric silsesquioxanes (POSS) derived from hydrolytic condensation of vinyltrimethoxysilane was validated by the spectral characterization, such as FTIR, UV-MALDI-TOF MS, etc. The models of 3D-amorphous cubic unit cells of different numbers of Si atom and hydroxyls generated during the hydrolytic condensation and the length of the organic side chain (T₆, T₇, T₈, T₉, T₁₀, T₈(OH)₂ and T₈(OH)₄ cells), as models were established with a materials visualizer module of Material Studio(MS) software. The cells were optimized the configuration and calculated energy band structure and absorption coefficient (a) with Castep module of MS which is the quantum chemistry program based on density functional theory (DFT). The calculation results showed that the band gap was reduced with the number of Si atoms in POSS increased, but the presence of hydroxyl could make a significant reduction of them. The reduction of band gap would lower the frequency of the incident light that was absorbed by the POSS and heighten the wavelength of the absorbed incident light, which was proved by the calculation results of absorption coefficient. Such reduction was discussed in comparison with the vinyltri- methoxysilane hybrid systems.

Abstract: In this work, the mesoporous zeolite molecular sieve (ZMS, SBA-15) was prepared by rice hull ash (RHA) and the surface of ZMS pore was modified by (3-mercaptopropyl) trimethoxysilane (MCPMS) with sulfhydryl (SH) as active group connecting to the SBA-15 pore surface. The capacity of removing ammonia-nitrogen (NH₃-N) in water will be increased because of the increasing in adsorption active groups. The micro-structures of SBA-15-SH were characterized by FTIR, SEM, TEM, SAXRD. The diffusion and adsorbed behavior of NH₃-N in pores of the modified ZMS was simulate by using a molecular dynamic simulation (MDS) program of the Materials Studio software (MSS) which facilitated study of the effect of this modification on pore structure and adsorption capacity. As results of the experiments, the MCPMS-modified ZMS showed more efficient in removing NH₃-N in drinking water than before the modification under the same conditions.

Abstract: In this work, the mesoporous zeolite molecular sieve (ZMS, SBA-15) was modified by polyhedral ologomeric silsesquioxane (POSS) with sodium carboxylates(-COONa) and sodium sulphonate (-SO3Na) as ion-exchanging active group. With this approach, the capacity of removing ammonia-nitrogen (NH3-N) in water will be greatly increased because of changing and increasing of active groups. The exchangeing process between NH3-N and the active group in the pore of POSS modified SBA-15 including sodium silanolate (-SiONa), -COONa and -SO3Na was simulated by using Dmol3 program of the Materials Stutio (MS)software which is the quantum chemistry program based on density functional theory (DFT). In the simulation process the transition state of the exchanging reaction was searched with LST/QST algorithm and the activation energy of reaction was calculated. As the results of simulation and calculation, the activation energy of exchanging reaction between NH3-N and sodium sulphonate (-SO3Na) is smallest and the thermal effect of exchanging reaction between NH3-N and -SO3Na is lowest in all exchanging reactions, which means the exchanging reaction between NH3-N and -SO3Na proceeds more easily than others two exchanging reactions. The POSS-SO3Na is a better modifier for SBA-15 to remove NH3-N in water.

Abstract: The cold roll B-added Ti-IF steel is annealed for different times at 810 oC. The microstructure development is studied by Optical Microscope（OM） and the concentration of boron and phosphorus segregation at grain boundary is measured by Auger electron spectroscopy（AES）. The result shows that the grain of the cold- rolled sample is elongated along the rolling direction and the elongated grains become into equi-axis shape after annealing 60 to 180sec. Boron and phosphorus segregated at gain boundaries. But boron’s concentration at grain boundary is higher than that of phosphorus and increase from 5at.% or so to about 10at% after annealing 150sec, Then boron’s concentration decrease slowly to 8at.% at 240sec. While phosphorus’s concentration increase to the max of 2.5at.% or so at 120sec, then its concentration decrease to 1at.% or so after annealing 240sec.

Abstract: The study herein investigated the bond strength of original veneer, dyeing veneer and fixative veneer in terms of moisture content. The test results were shown that: bond strength of untreated veneer, dyeing veneer and fixation veneer were all decreased with moisture content increasing. Furthermore, wet strength of these three kind of veneers were lower than the dry strength themselves evidently. The study also found that dry strength and wet strength of original veneer were all bigger than those of dyeing veneer and fixative veneer evidently.

Abstract: Based on (3-methacryloxypropyl)-Polyhedral oligomeric silsesquioxane (MP-POSS) (MP), vinyl-POSS (VP), (3-glycidoxypropyl)-POSS (GP) and modified with 10, 20 and 30 wt-% titanium tetrabutoxide (TTB), three hybrid nanofilms (f-MPT, f-VPT and f-GPT) were prepared using hydrolytic condensation and crosslinking. The average transparency (AT) and absorption coefficients (AC) of the films were measured in the ranges of 280-2500 nm. The average transparency (AT) values of three films were about 10-11% (280-320 nm), 78-80% (320-400 nm) and 85-89% (750-2500 nm), which implies that these films indeed can provide a physical barrier for blocking the UV-B absorbed into greenhouse, indicating functionality of the POSS/TiO2 materials as the sun protection ingredients. The AT values of three films were in the order of f-MPT>f-GPT>f-VPT due to complete-cage structures of building blocks (POSS) and the size of organic branches covalently bonded to the silica network in the molecular structures. This indicates that VPT powder might be significantly better to selected for the sun protection factor (SPF). Lower mtransparency of the films containing 30 wt-% TTB fractions is ascribed to more amounts of TTB in the modified films.

Abstract: Based on (3-methacryloxypropyl)-Polyhedral oligomeric silsesquioxane (MP-POSS) (MP), vinyl-POSS (VP), (3-glycidoxypropyl)-POSS (GP) and modified with 5, 10, 15, 20 and 25 wt-% titanium tetrabutoxide (TTB), three hybrid nanofilms (f-MPT, f-VPT and f-GPT) were prepared using hydrolytic condensation and crosslinking. The transparency of the films was measured at the ranges of ultraviolet A (UV-A) (320-400 nm) spectrum which can cause a much greater risk of skin changes. The average transparency (AT) values of three films were about 65-78% (320-350 nm) and 85-89% (350-400 nm), which implies that these films indeed can provide a physical barrier for blocking the UV-A absorbed into the skin, indicating functionality of the POSS/TiO2 materials as the sun protection factor (SPF) ingredients in a sunscreen. The AT values of three films were in the order of f-MPT>f-GPT>f-VPT due to complete-cage structures of building blocks (POSS) and the size of organic branches covalently bonded to the silica network in the molecular structures. This indicates that VPT powder might be significantly better to selected for the SPF. The TTB addition results in the hybrid structure containing TiO2 which causes a decrease in the AA radiation from sunlight. Lower transparency of the films containing 25 wt-% TTB fractions is ascribed to more amounts of TTB in the modified films.