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991.
Jiaying Yan Yaqing FengXiao Peng Yuanchao LiNuonuo Zhang Xianggao LiBao Zhang 《Tetrahedron letters》2013
Four π-extended, β,β′ aromatic ring fused porphyrins including mono- and opp-dibenzoporphyrins bearing two carboxyl groups at only one fused benzo group were synthesized. The optical results by UV–vis spectroscopy indicate that when compared with the absorption spectra of monobenzoporphyrins, greater light-harvesting capabilities can be realized for opp-dibenzoporphyrins with two benzo group at the opposite β,β′ positions of the porphyrin. The photovoltaic properties of these π-extended porphyrins were examined for the first time and the highest conversion efficiency of 1.62% was realized for opp-dibenzoporphyrin 8a-sensitized solar cell, which is ∼60% higher than that of monobenzoporphyrin 4a based solar cell indicating the effect of an extra aromatic π conjugation on the light-harvesting capabilities of π-extended porphyrins. Subsequent DFT calculation results supported our results obtained in the optical and photovoltaic studies. 相似文献
992.
Ya Gao Nan Chen Weiwu Hu Chuanping Feng Baogang Zhang Qian Ning Bin Xu 《Journal of solution chemistry》2013,42(4):691-704
Adsorption is an effective treatment process for removing phosphorus and thus controlling eutrophication. In this study, a clay composite material called Al–dolomite–montmorillonite (Al–DM) was prepared and characterized. Al–DM performed well with respect to phosphate removal, with its performance depending on the Al–DM loading, contact time, initial phosphorus concentration and initial solution pH. Adsorption mechanisms were investigated by conducting batch tests on phosphate adsorption using the Al–DM. The adsorption process fitted both the pseudo-second-order kinetics model and the intra-particle diffusion model. The Langmuir, Freundlich and BET models all adequately described the adsorption isotherm data. Thermodynamic studies showed that the adsorption process was endothermic and spontaneous in nature. Al–DM is an effective adsorbent for phosphate removal mainly due to its hierarchical porous structures as shown by characterization with SEM and EDS. Chemical changes occurring before and after adsorption in a water environment indicated that Al–DM had little negative effect on water quality. 相似文献
993.
Wei Chang Lijuan Liu Jin Zhang Qiwei Pan 《Journal of Dispersion Science and Technology》2013,34(5):639-642
A kind of emulsifier-free latex (FL) was successfully synthesized from styrene (St) and butyl acrylate (BA) with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) as a reactive emulsifier. The particle size of latex particles, stability against electrolytes, minimum film forming temperature (MFT) and water contact angle (CA) were evaluated and compared with a conventional latex (CL). Test results show that FL has larger particle size, better stability against electrolytes and lower MFT value compared with CL; higher AMPS content leads to smaller particle size and smaller water CA. 相似文献
994.
Jie-Guang Song Gang-Chang Ji Shi-Bin Li Lian-Meng Zhang 《Journal of Dispersion Science and Technology》2013,34(4):529-533
SiC@A1(OH)3-Y(OH)3 core-shell composite particles are synthesized by co-precipitation method for strengthening the antioxidation of SiC at high temperature. To reach better A1(OH)3-Y(OH)3 composite shell and higher coating ratio on the SiC particles surfaces, SiC particles must be adequately dispersed in the SiC suspension during the coating process. The dispersion mechanism of SiC particles is investigated by the sedimentation method. Through test and analysis, the optimum conditions of the dispersion of SiC particles in the SiC suspension are sedimentating for 10 minutes, ultrasonic dispersion for 10 minutes, the lower SiC concentration, pH = 9, the dispersant content for the 2% volume of SiC suspension and using the polyelectrolyte dispersant, respectively. 相似文献
995.
Fu-Qiang Jin Jian-Chun Zhang Min Li Xin-Min Hao Hua Zhang 《Journal of Dispersion Science and Technology》2013,34(8):1148-1151
NaOH/poly(sodium acrylate) composites were prepared by in situ polymerization of acrylic acid with an overneutralization level by adding excess NaOH. The composites were studied by XRD, IR and 23Na MAS NMR spectroscopy. The results showed that the high neutralization degree (>100%) may lead to a complete polymerization. Both XRD and 23Na MAS NMR spectra did not show any peaks of phase-separated NaOH or Na2CO3 until the neutralization degree was up to 217.5%. It can be presumed that the aggregates of Na+ ions can contain approximately two Na+ units for every carboxyl group before the phase separation. 相似文献
996.
Ling Zhang Hongqi Wan Lei Chen Huidi Zhou Jianmin Chen 《Journal of Dispersion Science and Technology》2013,34(6):846-850
Sb2S3 nanoparticles surface-modified with S-tetradecyl N, N-dihydroxyethyl dithiocarbamate (C14DTC-Sb2S3) have been synthesized via extraction of Sb2S3 colloidal particles from ethylene glycol into toluene in the presence of C14DTC. The obtained products were characterized by high-resolution transmission electron microscope (HRTEM) and Fourier transformation infrared (FTIR), and their tribological behaviors as an additive in liquid paraffin were investigated using a four-ball tribometer. The results show that C14DTC-Sb2S3 nanoparticles can significantly improve the friction reduction, anti-wear, and load-carrying properties of base oils. The preliminary lubrication mechanism was discussed based on the SEM and XPS investigation of the rubbed surfaces. 相似文献
997.
A hydrophilic and temperature-induced degradation drug, vinorelbine bitartrate (VB)-loaded phosphatidylethanolamin sterically stabilized liposomes (PSLs) were prepared by the thin film hydration method. Liposomes were made of phosphatidylethanolamine: cholesteryl: oleic acid (PE: CHOL: OA, 6:4:3 mass/mass). The mean particle size of the PSLs ranged from 600 to 650 nm. The transmission electron microscope (TEM) images displayed that the shape of the PSLs was multilamellar vesicles with smooth surface. The highest entrapment efficiency (EE) and drug loading capacity (DL) could reach up to 81.2 and 16.6%, respectively. The studies of drug release showed that the drug release could last for much more than 48 hours. The PSLs was evaluated by comparing the rate of release of encapsulated VB in different phosphate buffer solution (PBS). 相似文献
998.
Weihua Zhang Judah Friese Kurt Ungar 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(1):69-73
In this study, soil samples were collected at Canadian embassy in Tokyo (about 300 km from Fukushima) on 23 March and 23 May of 2011 for purposes of estimating concentrations of radionuclides in fallout, the total fallout inventory, the depth distribution of radionuclide of interest and the elevated ambient gamma dose-rate at this limited location. Some fission products and actinides were analyzed using gamma-ray spectrometry, alpha spectrometry and liquid scintillation counting. The elevated activity concentration levels of 131I, 132I, 134Cs, 137Cs, 136Cs, 132Te, 129mTe, 129Te, 140Ba and 140La were measured by the gamma-ray spectrometer in the first sample collected on 23 March. Two months after the accident, the 134Cs and 137Cs became only detectable nuclides. A mass relaxation depth of 3.0 g/cm2 was determined by the activities on the depth distribution of 137Cs in a soil core. The total fallout inventory was thus calculated as 225 kBq/m2 on March sampling date and 25 kBq/m2 on May sampling date. The ambient gamma dose-rates in the sampling area estimated by the fallout fission products inventory and 137Cs depth distribution ranged from 184 to 38 nGy/h. There was no detectable americium or plutonium in the soil samples by alpha spectrometry. Although 90Sr or 89Sr were detected supposedly as a result of this accident, it was less than the detection limit, which was about 0.4 Bq/kg in the soil samples. 相似文献
999.
Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively (designated as BAPNCP, BAPBACP and BAPNPGCP, respectively), were synthesized and characterized. In addition, the effects of backbone structures on curing behaviors of the monomers and thermal and flammability properties of the resulting polymers were systematically studied. The results indicated that BAPNPGCP displayed the highest enthalpy of the curing reaction associated with the ring-opening of benzoxazine, which was due to the effect of benzoxazine ring content per unit mass. Interestingly, the 5 wt% weight loss temperature and char residue after thermogravimetric test for poly(BAPNPGCP) were 8 °C and 7% higher than those of poly(BAPBACP). Meanwhile, the total heat release of poly(BAPNPGCP) was less than half of that for poly(BAPBACP), indicating the substantial effect of benzoxazine ring content on flammability and char formation. Furthermore, it was found that poly(BAPNCP) gave the best thermal stability and flame retardancy, which was due to the synergistic effect between naphthalene group and benzoxazine ring content. This study provides new insight into the curing behavior of benzoxazine and further understanding on the high performance of polybenzoxazine. 相似文献
1000.
Liangliang Zhu Fuchun Shen Jing Zhang Cai-Feng Wang Su Chen 《Colloid and polymer science》2013,291(9):2147-2154
We report herein a facile approach of fabricating fluorescent supraballs from CdTe nanocrystals (NCs)-loaded acrylosilane microemulsion by a simple microfluidic strategy. Initially, core–shell acrylosilane microemulsion with poly(methylmethacrylate-co-butylacrylate-co-vinyltri(isopropoxy)silane) (poly (MMA-co-BA-co-VPS)) as the core and poly(methylmethacrylate-co-butylacrylate-co-vinyltri(isopropoxy)silane-co-acrylamide) (poly(MMA-co-BA-co-VPS-co-AM)) as the shell were synthesized by differential microemulsion polymerization. Subsequently, CdTe NCs were assembled with these acrylosilane microemulsion particles in the presence of N′-(ethylcarbonimidoyl)-N, N-dimethylpropane-1, 3-diaminemonohydrochloride. Eventually, we fabricated uniformly distributed fluorescent supraballs using the as-prepared CdTe-loaded acrylosilane microemulsion as the discontinuous phase, and methylsilicone oil as the continuous phase by means of a microfluidic device. These fluorescent supraballs display unique colors and favorable fluorescence, which might be useful in optoelectronic applications, such as fluorescent switches, light-emitting diode displays, and illuminations. 相似文献