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981.
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
982.
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
983.
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
984.
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
985.
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
986.
The mechanism of α-acetyl-γ-butyrolactone (ABL) synthesis from γ-butyrolactone (GBL) and ethyl acetate (EtOAc) was explored by detecting the material changes involved and the enthalpies of formation of the synthons, products, and possible intermediates were calculated using the density functional theory. GBL forms a carbanion of γ-butyrolactone by losing an α-H under strongly alkaline conditions. ABL is then obtained via two reaction mechanisms. One of the reaction mechanisms involves direct reaction of the carbanion of GBL with EtOAc to produce ABL. The other involves the formation of a carbanion of α-(2-hydroxy-tetrahydrofuran-2-yl)-γ-butyrolactone through the reaction of two molecules of GBL, and the subsequent combination of this anion with EtOAc to produce ABL. ABL is thus formed through the above two kinds of competitive ester condensation reactions. It is unnecessary to take into account synthons’ local thickness, and their self-condensation under these conditions. Both reactions of the carbanion of GBL with EtOAc and GBL are exothermic, so the control of their reaction rate is the key to their security. Considering the reasons above, this work applied synthon as the solvent, and avoided environmental pollution by alkylbenzene; also, accidents such as red material and fire were avoided by specific surface area of sodium metal control. Effective isolation of the organic and aqueous phases was performed using the salting out method. Thus, an environmentally friendly, safe, simple, and efficient new method for the synthesis of ABL with the yield higher than 90 % has been established. 相似文献
987.
Xiaomei Zhang Liang Shi Guocai Xu Chaoyue Chen 《Journal of inclusion phenomena and macrocyclic chemistry》2013,75(1-2):147-153
Two new β-CD-calix[4]arene coupling products 3,4 which contained one or two β-CD units in molecules were synthesized by ammonolysis of p-tert-butyl-25,27-dihydroxyl-26,28-di (ethoxy carbonyl methoxyl) calix[4]arene 1 and mono-6-ethylenediamino-6-deoxy-β-CD 2, and their structures were confirmed by 1H NMR, IR and MS (Maldi-Tof). The probable mechanism for forming 3 was discussed also. Using water-insoluble coupling product 3 as an adsorbent, the influences of the adsorption capacities of 3 including initial concentration, temperature and pH onto basic fuchsin (BF) and methylene blue (MB) from aqueous solution were investigated. Results showed that the adsorption capability of 3 to BF was obviously higher than that to MB at similar adsorption conditions. The values of %sorption to BF were over 90 % in range of initial concentrations from 20 to 140 mg L?1 whenas those to MB dropped rapidly from 92 to 58 %. The adsorptions of 3 to both BF and MB obeyed Freundlich adsorption isotherm well. 相似文献
988.
Shaogan Niu Lifen Zhang Jian Zhu Wei Zhang Zhenping Cheng Xiulin Zhu 《Journal of polymer science. Part A, Polymer chemistry》2013,51(5):1197-1204
Well‐defined polyacrylonitrile (PAN) of high viscosity‐average molecular weight (Mη = 405,100 g/mol) was successfully synthesized using reversible addition‐fragmentation chain transfer polymerization. The polymerization exhibits controlled characters: molecular weights of the resultant PANs increasing approximately linearly with monomer conversion and keeping narrow molecular weight distributions. The addition of 0.01 equiv (relative to monomer acrylonitrile) of Lewis acid AlCl3 in the polymerization system afforded the obtained PAN with an improved isotacticity (by 8%). In addition, the influence of molecular weights and molecular weight distributions of PANs on the morphology of the electrospun fibers was investigated. The results showed that, under the same conditions of electrospinning, average diameter (247–1094 nm) of fibers increased with molecular weights of PANs, and it was much easier to get “uniform” diameter fibers while using PANs with narrow molecular weight distributions as the precursor of electrospinning. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
989.
Chiral N-[1-benzyl-2-hydroxyethyl]-3-[2-oxo-pyrrole]propionamide (C16H22N2O3) was obtained unexpectedly from the reaction of oxazoline involving pyrrolidone with copper acetate monohydrate, and the structure was characterized by NMR, IR, elemental analysis, and X-ray analysis. 相似文献
990.
Zheng Wang Shuai Luo Dr. Shoude Zhang Wu‐Lin Yang Yang‐Zi Liu Prof. Dr. Honglin Li Prof. Dr. Xiaoyan Luo Prof. Dr. Wei‐Ping Deng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(21):6739-6745
The first catalytic enantioselective 1,3‐dipolar cycloaddition of azomethine ylides to α‐aminoacrylate catalyzed by a AgOAc/ferrocenyl oxazolinylphosphine (FOXAP) system was developed, which exhibits excellent exo‐ and enantioselectivity (92–99 % ee). This process provides efficient access to useful 4‐aminopyrrolidine‐2,4‐dicarboxylic acid (APDC)‐like compounds containing a unique quaternary α‐amino acid unit. 相似文献