醋酸酯麦芽糊精制备及性质研究

以麦芽糊精为原料,制备了醋酸酯麦芽糊精。研究各反应因素对产品取代度的影响,并以取代度为指标,通过正交试验确定其最佳工艺条件,同时对制备出来的醋酸酯麦芽糊精性质进行研究。结果表明,醋酸酯麦芽糊精制备最佳工艺为:反应温度30℃、p H 8.5、醋酸酐用量12%、反应时间3 h;相对于原麦芽糊精,改性后的麦芽糊精乳化性及乳化稳定性提高,凝沉性降低,冻融稳定性增强。     

Water sorption isotherms and thermodynamic properties of pearl millet grain

The water sorption isotherms of pearl millet grain and the thermodynamic properties obtaining during the process of drying pearl millet were examined. Equilibrium moisture content (X_eq) was determined under several temperature (T) and relative humidity (RH) conditions. The X_eq data were correlated by six mathematical models. The modified Henderson was the model that best fitted the experimental data. The X_eq decreased with an increase in T at constant RH. Hysteresis was also studied; increasing T led to a decrease in this phenomenon. Integral isosteric heat of sorption (Q_st), differential entropy (ΔS) and the enthalpy–entropy compensation theory were studied. Q_st values decreased when X_eq increased because the Q_st values of adsorption were lower than Q_st desorption values. The values of ΔS decreased with increases in X_eq, because ΔS values were higher for desorption than for adsorption. The enthalpy–entropy compensation theory is valid for describing the water sorption processes of pearl millet grain.     

硝铵类炸药易出问题的原因分析

针地硝铵类炸药在保管及使用过程中常出现的一些问题，分析了产生这些问题的原因，并提出了预防及改进措施。     

大米麦芽糊精的性质及应用

介绍了大米麦芽糊精的制备、粘度、吸湿性等方面的独特性,以及大米麦芽糊精在食品、医药、造纸、建筑等行业的应用。     

涤纶短纤油剂粘着性能研究

从油剂的粘着性与涤纶短纤维的集束性、吸湿性关系入手,讨论了磷酸酯碳原子数对油剂粘着性及油剂粘着性对纤维棉纺过程的影响。     

Preformulation characterization and in vivo absorption in beagle dogs of JFD,a novel anti-obesity drug for oral delivery

JFD (N-isoleucyl-4-methyl-1,1-cyclopropyl-1-(4-chlorine)phenyl-2-amylamine·HCl) is a novel investigational anti-obesity drug without obvious cardiotoxicity. The objective of this study was to characterize the key physicochemical properties of JFD, including solution-state characterization (ionization constant, partition coefficient, aqueous and pH-solubility profile), solid-state characterization (particle size, thermal analysis, crystallinity and hygroscopicity) and drug-excipient chemical compatibility. A supporting in vivo absorption study was also carried out in beagle dogs. JFD bulk powders are prismatic crystals with a low degree of crystallinity, particle sizes of which are within 2–10?μm. JFD is highly hygroscopic, easily deliquesces to an amorphous glass solid and changes subsequently to another crystal form under an elevated moisture/temperature condition. Similar physical instability was also observed in real-time CheqSol solubility assay. pK_a (7.49?±?0.01), log?P (5.10?±?0.02) and intrinsic solubility (S₀) (1.75?μg/ml) at 37?°C of JFD were obtained using potentiometric titration method. Based on these solution-state properties, JFD was estimated to be classified as BCS II, thus its dissolution rate may be an absorption-limiting step. Moreover, JFD was more chemically compatible with dibasic calcium phosphate, mannitol, hypromellose and colloidal silicon dioxide than with lactose and magnesium stearate. Further, JFD exhibited an acceptable pharmacokinetic profiling in beagle dogs and the pharmacokinetic parameters T_max, C_max, AUC_0–t and absolute bioavailability were 1.60?±?0.81?h, 0.78?±?0.47?μg/ml, 3.77?±?1.85?μg·h/ml and 52.30?±?19.39%, respectively. The preformulation characterization provides valuable information for further development of oral administration of JFD.     

硝酸铵防吸湿性研究

应用表面活性理论和技术，用表面活性剂和添加剂对ＡＮ进行特殊的处理，测定了改性ＡＮ的吸湿性，系统地分析了降低ＡＮ吸湿性的原因，结果表明，表面活性剂和添加剂能够有效地降低ＡＮ吸湿性，同时，也得出了较理想的表面活性剂和添加剂。     

Improvement of humidity resistance of water soluble core by precipitation method

Water soluble core has been widely used in manufacturing complex metal components with hollow configurations or internal channels; however, the soluble core can absorb water easily from the air at room temperature. To improve the humidity resistance of the water soluble core and optimize the process parameters applied in manufacturing of the water soluble core, a precipitation method and a two-level-three-full factorial central composite design were used, respectively. The properties of the cores treated by the precipitation method were compared with that without any treatment. Through a systematical study by means of both an environmental scanning electron microscope (ESEM) and an energy dispersive X-ray (EDX) analyzer, the results indicate that the hygroscopicity can be reduced by 20% and the obtained optimal process conditions for three critical control factors affecting the hygroscopicity are 0.2 g.mL-1 calcium chloride concentration, 4% water concentration and 0 min ignition time. The porous surface coated by calcium chloride and the high humidity resistance products generated in the precipitation reaction between calcium chloride and potassium carbonate may contribute to the lower hygroscopicity.     

超支化聚酯的合成及其对PET纤维的改性研究

以三羟甲基丙烷作为中心核,二羟甲基丙酸为合成单体,对甲苯磺酸作为催化剂,采用一步法分别合成了第二代、第三代、第四代不同代数的端羟基超支化聚酯(HBP),并对其结构进行了表征.将不同代数的HBP与聚对苯二甲酸乙二醇酯(PET)共混纺丝制备了HBP/PET共混纤维,研究了纤维的流变性能、力学性能、染色性能和吸湿性能.结果表...     

海藻酸钠/水溶性甲壳素共混纤维的制备和性能研究

用自制的湿法纺丝机制备了海藻酸钠/水溶性甲壳素共混纤维,并用红外光谱和扫描电镜对其进行了表征,且对纤维进行了单纤维拉伸测试和吸水性能测试。结果表明:共混纤维中确实有水溶性甲壳素的存在;从纤维的表面形态可以看出在轴向上有明显的筋状结构;拉伸结果表明共混纤维的平均断裂强度为16.25cN/tex,线密度为2.47dtex;共混纤维对水和盐水的吸收率都不高,但比纯海藻酸钙纤维的略高。