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91.
Yan Wu Tiewei Wang Mingjun Li Tengfei Fan Hongxia Gao Xuemin Wu 《Journal of Polymer Research》2011,18(5):1147-1158
A new amphiphilic hyperbranched poly (amine-ester)-poly(ε-caprolactone) copolymer (HPAE-co-PCL) was synthesized by ring-opening polymerization of ε-caprolactone and branched poly (amine-ester) (HPAE-OHs) with Sn(Oct)2 as catalyst. The chemical structures of copolymers were determined by FT-IR, 1H-NMR (13C-NMR), thermo gravimetric analysis apparatus (TGA) and differential scanning calorimetry (DSC). Camptothecin (CPT)-loaded copolymer nanoparticles were prepared by the oil-in water (o/w) emulsion technique method. Their physicochemical characteristics, e.g. morphology and nanoparticles size distribution were then evaluated by means of fluorescence spectroscopy, environmental scanning electron microscopy (ESEM), and dynamic light scattering (DLS). CPT-loaded nanoparticles assumed a spherical shape and have unimodal size distribution. It was found that the chemical composition of the nanoparticles was a key factor in controlling nanoparticles size, drug-loading content, and drug release behavior. As the molar ratio of ε-caprolactone to HPAE increased, the nanoparticles size and drug-loading content increased, and the drug release rate decreased. The antitumor activity of the CPT-loaded HPAE-co-PCL nanoparticles against human hepatoma HEPG2 cells was evaluated by 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The CPT-loaded HPAE-co-PCL nanoparticles showed comparable anticancer efficacy with the free drug. 相似文献
92.
93.
Showkat A. Bhawani Othman Sulaiman Ziya A. Khan Rokiah Hashim Mohamad N. M. Ibrahim 《Journal of surfactants and detergents》2011,14(2):301-305
The mutual separation of a mixture of cetyltrimethyl ammonium chloride (CTAC), methyl trioctyl ammonium bromide (MTOB), dodecyltrimethyl ammonium chloride (DTAC), benzyltrimethyl ammonium chloride (BTAC) and tetrabutyl ammonium bromide (TBAB), was achieved on silica high performance thin layer chromatographic plates using dimethyl sulfoxide with aqueous sodium-l-tartrate dibasic dihydrate as the solvent system. The effect of concentration of sodium-l-tartrate dibasic dihydrate on the mobility of all the five quaternaries was examined. The limit of detection of CTAC, MTOB, DTAC, BTAC and TBAB was estimated as 0.6, 0.6, 0.3, 0.6 and 0.3 μg/zone, respectively. The method developed was utilized to identify these surfactants in different spiked water samples after their preliminary separation. 相似文献
94.
95.
The desired benefits of the finished soap product are governed by a professional selection of appropriate raw materials, the manufacturing process or both. A better understanding of the crystallization of the soap microstructure is needed which has direct effects on the properties of final products. Soap microstructures and soap composition are not only determined by the length of hydrophobic fatty chain, saturation extent of fatty acid chain, fatty acid distribution but also by the cation effect. Thus, four different fatty acid compositions and the effect of sodium and potassium cations were studied. The performance of the potassium and sodium bar soaps prepared was monitored and was correlated with solid phase thermal analysis. The microstructural effect was examined using ATR-FTIR, FESEM and XRD. The specific ion effect and ion interaction involving both cations and carboxylate anions on different chemical compositions was correlated. 相似文献
96.
Karim BENYAHI Youcef BOUAFIA Salma BARBOURA Mohand Said KACHI 《Frontiers of Structural and Civil Engineering》2018,12(4):577-593
The present study goes into the search for the safety domain of civil engineering structures. The objective is to show how a reliability-evaluation brought by a mechanical sizing can be obtained. For that purpose, it is necessary to have a mechanical model and a reliability model representing correctly the behavior of this type of structure.It is a question on one hand, to propose a formulation for the nonlinear calculation (mechanical nonlinearity) of the spatial structures in trusses, and on the other hand, to propose or to adapt a formulation and a modeling of the reliability. The principle of Hasofer-Lind can be applied, in first approach, for the reliability index estimation, scenarios and the probability of failure.The made check concerned metallic in truss structures. Finally, some structures are calculated using the method adapted by Hasofer-Lind to validate the probability approach of the reliability analysis. 相似文献
97.
Pakorn Suramanee Sirilux Poompradub Rojrit Rojanathanes Patchanita Thamyongkit 《Catalysis Letters》2011,141(11):1677-1684
Abstract
This work describes a catalytic oxidation of glycerol using citrate-stabilized gold nanoparticles (citrate-AuNPs) having a mean diameter of 22 ± 3 nm. A careful product analysis was performed by mean of high-performance liquid chromatography, liquid chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy. Effects of reaction temperature, oxygen pressure, catalyst and reactant concentration, and NaOH/glycerol molar ratio on glycerol conversion, and product yields were investigated. The glycerol conversion and glyceric acid yield were optimum when the oxidation was performed using 0.6 M glycerol and NaOH at 80 °C under 3 bar of O2 pressure in the presence of 50 ppm citrate-AuNPs catalyst for 3 h. 相似文献98.
The utilization of microencapsulated phase change material wallboards for energy saving 总被引:1,自引:0,他引:1
See-Hoon Lee Sang-Jun Yoon Young-Gu Kim Jae-Goo Lee 《Korean Journal of Chemical Engineering》2011,28(11):2206-2210
Wallboards with micro encapsulated phase changing material (micro PCM) were used to investigate the performance and the energy saving characteristics as building materials in winter and summer climate conditions. The test house consisted of a boiler with under floor heating system, an air conditioner, micro PCM wallboard room and conventional wallboard room. The outer temperature of the rooms could be artificially controlled at the temperature range of −12 to 35 °C. Micro PCM content in wallboards was 0–4 kg/m2. The melting temperature and latent heat of Micro PCM are 23 °C and 211 J/g. Also, micro PCM shows stable mechanical strength under 500 psi. As micro PCM content increased, the temperature fluctuations decreased. In case of micro PCM wallboard, temperature profiles in the room show stable and comfortable ranges. The optimum amount of micro PCM in wallboard to maximize energy saving efficiency was around 3 kg/m2. 相似文献
99.
Yanjun Liu Yiqian Jiang Hengbo Yin Weiguang Chen Yutang Shen Yonghai Feng Lingqin Shen Aili Wang Tingshun Jiang Zhanao Wu 《Korean Journal of Chemical Engineering》2011,28(12):2250-2254
Gas phase methylation of methyltrichlorosilane with methyl chloride to high-valued dimethyldichlorosilane was carried out by using metallic aluminum as a chlorine acceptor in the co-presence of activated carbon, tin, and zinc. The addition of activated carbon in metallic aluminum significantly enhanced the methylation of methyltrichlorosilane, and dimethyldichlorosilane was dominantly produced. Activated carbon played a catalyst role in the methylation reaction. When active metals, such as tin and zinc, were added in the mixture of aluminum and activated carbon, the active metals and activated carbon synergistically catalyzed the methylation of methyltrichlorosilane with methyl chloride toward the formation of dimethyldichlorosilane. 相似文献
100.
Yi-Joon Kim Sang-Un Lee Wa Gao Chung-Han Chung Chang-Woo Son Jin-Woo Lee 《Korean Journal of Chemical Engineering》2011,28(7):1580-1586
The optimal conditions of the downstream process for recovery of pullulan produced by Aureobasidium pullulans HP-2001 were examined using response surface method (RSM). The optimal amount of diatomite in filter press and the optimal flow rate in a continuous flow centrifuge for removal of cells from the culture broth of A. pullulans HP-2001 were found to be 5.0% (v/v) and 2.0 L/min. Based on central composite design (CCD) experiments and analysis of variance (ANOVA) indicated that the optimal conditions for recovery of pullulan from the supernatant by precipitation were the volume ratio of ethanol (or isopropanol) to supernatant of 3.0: 1.0, the reaction time of 29.5 h, and the reaction temperature of 20.2 °C. The expected maximal recovery yields of pullulan using ethanol and isopropanol under optimized conditions were 79.2 and 85.5%, respectively. 相似文献