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61.
利用C18固相萃取膜评价有机氯污染物的亲酯性 总被引:6,自引:0,他引:6
采用C18 膜模拟生物体 ,探讨了化合物在膜与水相之间分配平衡的影响因素 ,测定了卤代苯类化合物的膜 /水分配系数 .结果表明 ,随着脂溶性的增加 ,化合物分配达到平衡的时间也将增加 ;C18膜 /水分配系数的大小与水相中化合物浓度的大小和C18膜量的多少无关 ;C18膜 /水分配系数 (KSD)与正辛醇 /水分配系数 (KOW)之间有较好的一致性 .C18膜材料的使用 ,为有机污染物脂溶性的评价提供了一个新的方法 ,并且这一方法为复合污染体系因脂溶性所引起的基本毒性量化预测创造了条件 . 相似文献
62.
G.?ScalabrinEmail author G.?Cristofoli M.?Grigiante 《International Journal of Thermophysics》2005,26(2):429-452
The fundamental structure of the model is based upon a detailed and innovative conformality analysis of the viscosity surfaces of pure fluids similar to that proposed for thermodynamic properties [G. Scalabrin et al. Fluid Phase Equilib. 170:23 (2000); Int. J. Refrig. 26:35 (2003)], resulting in the introduction of a new specific scaling parameter for viscosity, defined by a single experimental viscosity value. The model structure is based on two reference fluids for which pure-fluid viscosity dedicated equations (VDE) are available, which in this work are ethane and propane. The model is then extended to mixtures following the classical corresponding states (CS) one fluid model using mixing rules without interaction parameters. This gives the model a predictive character. It can be reliably applied in a wide range of pressure–temperature values, in both liquid and vapor phases, due to the validity ranges of the reference equations. The investigated mixtures include binary and multicomponent systems of both light and heavy n-alkanes and halogenated alkanes including R134a, R125, R152a, R143a, R22, R142b, R32, and R124 as components. For both families of fluids, the accuracy in terms of absolute average deviation (AAD) is within 2.68% in the vapor phase and 3.0% in the liquid phase. The model has also been validated for strongly azeotropic mixtures such as R32–R290 and R134a–R290 giving interesting results by fitting the interaction parameters on a limited subset of data. The effectiveness of the proposed procedure is enhanced by the comparison with a recently published advanced theoretical model.Paper presented at the Sixteenth European Conference on Thermophysical Properties, September 1–4, 2002, London, United Kingdom. 相似文献
63.
G.?ScalabrinEmail author L.?Piazza M.?Grigiante M.?Baruzzo 《International Journal of Thermophysics》2005,26(2):399-412
A predictive model for the thermal conductivity (TC), in a corresponding states (CS) format, is proposed here for mixtures of homologous fluids such as the halogenated alkanes (HA) and the alkanes (A), most of which are used as refrigerants. The predictive nature of the model originates from a new study carried out for the TC of pure fluids. For the dilute-gas term the model requires an individual correlation for each component, whereas for the excess contribution the model structure makes use of TC dedicated equations (TCDEs) of two reference fluids, which in this work are methane and R134a. The mixture model adopts specific mixing rules for each of the two TC contribution terms: the dilute-gas term 0mix is obtained from the Mason and Saxena mixture model, while the excess term E mix is determined from the Wong et al. mixing rules in the one fluid model approach. Setting the mixing rules interaction coefficients to unity, the resulting model presents a completely predictive character. The model has been tested on both liquid and vapor phases of the following systems: R32/R125, R32/R134a, R125/R134a, R404a, and R32/R134/R125. For a total of 1223 experimental points in the liquid phase, the overall AAD is 5.39%, while for a total of 2358 points in the vapor phase, the AAD is 2.62%. These predictive mode performances can then be regarded as particularly satisfactory and are of a level similar to the claimed experimental uncertainty. An improved version of the model is also proposed for modeling azeotropic mixtures. The results reached in this case for a total of 1989 experimental points give an average AAD of 5.30%. Considering both the predictive nature and the simple computational procedure of the model, it significantly enhances the calculations of the TC of mixtures.Paper presented at the Sixteenth European Conference on Thermophysical Properties, September 1–4, 2002, London, United Kingdom. 相似文献
64.
In this study, a continuous “pad‐dry‐cure” process was developed for the first time to graft a cycloamine monomer, 3‐allyl‐5,5‐dimethylhydantoin (ADMH), onto several high performance fibers, including Nomex, Kermel, and a PBI/Kevlar blend. The influence of reaction conditions on the grafting copolymerizaiton was studied. It was found that in the presence of a difunctional monomer, poly(ethylene glycol)–diacrylate (PEG–DIA), ADMH could be readily grafted onto these fibers. After exposure to chlorine, the hydantoin structures in the grafted samples could be transformed into N‐halamines, which provided powerful, durable, and regenerable antibacterial activities against both gram‐negative and gram‐positive bacteria. The influence of hydrophobic/rigid properties of the fabrics on grafting reactions as well as on their antibacterial activities was discussed, and the importance of full contact was emphasized. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1032–1039, 2003 相似文献
65.
In the first part of this study, simultaneous addition of bromine and acrylate to the double bonds of castor oil was achieved. In the second part of the study, bromoacrylated castor oil (BACO) was reacted with toluenediisocyanate (TDI), to form a prepolyurethane (BACOP). The prepolyurethanes were reacted with styrene (STY), 2‐hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), and 3‐(acryloxy)‐2‐hydroxy propyl methacrylate (AHPMA) free radically, using the acrylate functional group to prepare the simultaneous interpenetrating polymer networks (SINs). 2,2′‐Azobis (isobutyronitrile) (AIBN) was used as the initiator and diethylene glycol dimethacrylate (DEGDMA) was used as the crosslinker. BACO and BACOP were characterized by IR, 1H‐NMR, and 13C‐NMR techniques. Synthesized polymers were characterized by their resistance to chemical reagents, thermogravimetric analysis, and dynamic mechanical thermal analyzer (DMTA). All the polymers decomposed with 6–10% weight loss in a temperature range of 25–240°C. MMA‐type SIN showed the highest Tg (126°C), while STY‐type SINs showed the highest storage modulus (8.6 × 109 Pa) at room temperature, with respect to other synthesized SINs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2947–2955, 2006 相似文献
66.
目的 在温和实验条件下制备卤胺季铵盐双活性抗菌剂,考察其抗菌活性并研究其在纤维基包装材料中的应用。方法 利用紫外-可见分光光度计标定标准曲线,考察双活性抗菌剂及负载该抗菌剂的纤维基包装材料的抗菌活性和再生复用性能。结果 双活性抗菌剂在质量浓度为0.25 g/mL时,15 min内对大肠杆菌和金黄色葡萄球菌的杀菌效果均达到100%;负载双活性抗菌剂的纤维基包装材料在15 min内对大肠杆菌和金黄色葡萄球菌的杀菌效果均达到100%;经3次抗菌性能再生后,双活性抗菌剂和纤维基抗菌包装材料的一次杀菌效果仍可达到100%。结论 双活性抗菌剂对革兰氏阴性菌(大肠杆菌)与革兰氏阳性菌(金黄色葡萄球菌)均有良好的灭菌作用,负载双活性抗菌剂的纤维基材料的灭菌效果良好,且抗菌性能可多次再生。 相似文献
67.
Sheng Huang Peng Huang Lei Wang Junbo Han Yu Chen Haizheng Zhong 《Advanced materials (Deerfield Beach, Fla.)》2019,31(42)
3D perovskites with typical structure of ABX3 are emerging as key materials to achieve high‐performance optoelectronic devices. The variation of A‐site cation is promising to achieve enhanced properties; however, is limited to a few available choices of methylamine, formamidine, and cesium. In this work, halogenated‐methylammoniums are developed as A cation to broaden the family of hybrid perovskites. Single crystals and colloidal nanocrystals of halogenated‐methylammoniums based perovskites are successfully synthesized, showing bright future as alternatives for device exploration. In particular, the improved thermal stability and low exciton binding energy from single crystals measurements are demonstrated and bright tunable emission from blue to green for colloidal nanocrystals is achieved. 相似文献
68.
69.
堵锡华 《哈尔滨工业大学学报》2009,(9):241-245
在分子拓扑理论基础上,定义了原子特征值iδ,由iδ建构基团染色指数mXA及其倒指数mXB,运用定量结构-性质相关技术研究了92个卤代芳烃分子的折光指数与分子结构的定量关系.通过多元回归的方法建立了mXA和mXB与折光指数的定量结构性质模型,回归方程的相关系数为0.902 6.对卤代芳烃折光指数的计算结果表明,预测值与实验值平均相对误差为0.47%.基团染色指数及其倒指数共同使用可以更好地反映出卤代芳烃的构效关系.采用留一法对模型进行交互检验,证明该模型具有很好的稳定性和预测功能. 相似文献
70.