竖向分层非饱和土主动土压力的计算与分析

为了减小经典库仑土压力理论与实际工程中竖向分层土压力之间的误差,在传统库仑土压力理论和有限土压力理论的基础上,考虑了非饱和土的强度特性,建立了挡土墙后竖向分层填土的静力学平衡关系,得到了竖向分层填土的主动土压力的计算公式.通过与现有理论对比分析,验证了本文理论的正确性.分别分析了填土性质参数及挡土结构几何参数对土压力的...     

Migration of 137Cs Adsorbed on Fine Soil Particles through Soil Layer

The experiments on the migration of ¹³⁷Cs adsorbed on fine soil particles in unsaturated sandy soil layers were carried out. The soil layer reduced the concentration of ¹³⁷Cs in the effluent, but did not retard its migration. The concentration of ¹³⁷Cs remained in the soil layer increased in proportion to the amount of ¹³⁷Cs introduced.

By the measurement of size distribution of fine soil particles, it was revealed that the concentration of ¹³⁷Cs in the effluent decreased exponentially with the length of layer in the case of monodispersed fine soil particles.

From these results, the first-order irreversible reaction formula was obtained in order to formulate the reaction of ¹³⁷Cs adsorbed on fine soil particles with soil layer. A good agreement was obtained between the predicted result by polydispersed irreversible model and experimental one.     

Interaction between disperse dye and water soluble polyester surfactant

Abstract

The interactions of a disperse dye with a series of polymeric surfactants of water soluble polyester structure have been studied by a spectrophotometric method. A type of 1:1 complex formation has been found in the interaction systems of disperse dye and water soluble polyester surfactants. The interactions have been shown to be hydrophobic in nature with the extent of interaction increasing with the increasing hydrophobicity of water soluble polyester surfactants.     

高耐候抗风蚀涂料的研制

介绍了一种高耐候抗风蚀涂料及其树脂的合成配方及工艺,并讨论了影响其漆膜性能的因素。     

Ti(OBu)_4/TiO_2-Al_2O_3催化合成聚(己二酸-1,4-丁二醇)酯

用Ti(OBu)4/TiO2-Al2O3催化剂合成了聚(己二酸-1,4-丁二醇)酯。Ti(OBu)4/TiO2-Al2O3合成聚(己二酸-1,4-丁二醇)酯的最佳反应条件:催化剂载体焙烧温度为750℃,焙烧时间为4 h,催化剂加入量为1.5%,n(己二酸)/n(1,4-丁二醇)=1∶(1.2~1.3),反应温度为165~170℃,反应时间4 h,在此条件下得到聚酯,酯化率为93.02%,Mn=3 080,Mn/Mw=1.206,催化剂可反复使用5次。     

Preparation and characterization of blends containing natural and some synthetic rubbers with synthesized aromatic polyester

This work deals with the synthesis of aromatic polyester (AP) from polyarylate [Bisphenol A (BPA)/dimethyl terephalate (DMT)/ethylene glycol (EG)] and maleic anhydride (MA) in presence of dibutyl tin oxide (DBTO) as a catalyst. Blends were prepared from candidated AP (10–30 phr) with different types of rubber [natural rubber (NR), acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR) and ethylene‐propylene‐diene monomer (EPDM)]. The obtained blends were subjected to physicomechanical measurements to evaluate their properties as efficient blends for economic industrial applications. In case of AP blended with rubber, better properties were obtained than that of rubber vulcanizates. The fatigue life values decreases by increasing the AP contents for all types of the tested blends. The equilibrium swelling (%) for the prepared blends exhibits different behavior in solvents like toluene and motor oil. The addition of N‐isopropyl‐N′‐phenyl‐p‐phenylene diamine (IPPD), as antioxidant, affects the properties of all the prepared products. These properties were in consequent with the data of the initial shear modulus, which is calculated from the Mooney‐Rivlin equation and the percentage of the equilibrium swelling. Scanning electron microscope (SEM) was used to study the morphological structure; the SEM results show the changes in surface of the rubber before and after being blended with AP. The investigated blends are considered a new trend in giving products with variable physicomechanical characteristics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and characterization of fluorescent polymer magnetic particles

Magnetic iron oxide (maghemite, Fe₃O₄) particles were encapsulated with fluorescent polymer phase. The resulting fluorescent magnetic polymer particles were characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimeter analysis (TGA), reflection optical microscopy, differential scanning calorimeter (DSC), Fritsch particle sizer, scanning electron microscopy (SEM), powder X‐ray diffractometer (XRD), and vibrating sample magnetometer (VSM) measurements. FTIR and XRD confirmed the presence of iron oxide in polymer phase. The TGA and DSC measurements indicated that the magnetic polymer particles have more than 50% iron oxide content and high thermal stability. SEM and reflection optical microscopy under UV light revealed that all maghemite particles were embedded in the polymer spheres and have fluorescent characteristics. The size‐distribution analysis of prepared magnetic particles was shown that the means diameter of the particles slightly increased. According to our magnetometry data, shape of the loops evidences the ferromagnetic character of the material and no evidence of superparamagnetism was seen. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Flame retardant polyesters. III. Fibers

Most of the commercial flame retardant (FR) polyester fibers are produced using copolymerization with phosphorous FRs. We investigated the fiber properties, dyeing properties, and flame retardancy according to the phosphorous FR type. The physical properties of both the fibers are similar and suitable for textile application. But the dye adsorption rate is much faster in the case of main chain type. This is resulted from higher chain mobility analyzed by glass transition temperature. The main chain type FR polyester fiber adsorbed the dyestuff at lower temperature and reached exhaustion more quickly. And the resistance to chemicals such as acidic and alkaline solutions at high temperature have similar tendency with dye absorption. The migration of dyestuffs and chemicals into the polymer chain has good correlation with chain mobility of the polymers. The main chain type polyester fiber shows better flame retardancy than pendant type polyester, which might be brought about from more rapid degradation into polyphosphoric acid. The main chain type polyester fiber shows better flame retardancy than pendant type polyester. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Enhancement of melt elasticity for poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) by addition of weak gel

Rheological properties in a molten state are studied extensively for poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate), PHB‐HV, with a small amount of crosslinked poly(epichlorohydrin), PECH, having low density of crosslink points. It is found that adding 2 wt % of xPECH greatly enhances the melt elasticity of PHB‐HV, one of the serious defects of microbial PHB, whereas it has no effect on the shear viscosity. As a result, viscoelastic nature, and thus processability, of PHB‐HV can be controlled by blending the crosslinked PECH. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

聚酯电容器与电容膜生产现状及发展趋势

介绍了国内外电容器市场态势和发展趋势,重点阐述了以聚酯和聚丙烯为代表的薄膜电容器的国内外市场状态和发展趋势,着重分析了聚酯电容器与电容膜的特性及应用,并与聚丙烯作了比较,以及聚酯电容膜在节能灯和片式化、小型化电容器领域的应用前景。