玉米中类胡萝卜素的研究进展

玉米中富含以玉米黄素、叶黄素为主的类胡萝卜素,它们具有很强的抗氧化性能,对人体有保健作用,近年来又被发现对预防癌症有一定功效。文章综述了国内外有关玉米中类胡萝卜素相关研究进展,包括类胡萝卜素组成、性质、功能探索及制备研究等。     

Study on effect of polydimethylsiloxane in intumescent flame retardant polypropylene

The effect of polydimethylsiloxane (PDMS) in intumescent flame retarded polypropylene (PP) containing melamine phosphate (MP) was studied using limiting oxygen index (LOI), UL-94 test, thermogravimetric analysis (TG), real time Fourier transform infrared (FTIR) and pyrolysis/gas chromatogram/mass spectrometry (Py–GC/MS). It was found that the addition of PDMS into the PP/MP composites leads to a decrease in the LOI values of the PP/MP/PDMS composites, and the values increase gradually with the increase of the PDMS content. The UL-94 test results indicate that the PP/MP/PDMS composite with 30% PDMS reaches the V-0 rating compared with no rating of the PP/MP composite at the same MP loading. The water resistance of the PP/MP/PDMS composites was investigated, and the improved water leaching of MP was observed. The TG and RTFTIR results illustrate the thermal stability of the PP/MP composites containing PDMS is improved. Moreover, the pyrolysis of the PP/MP/PDMS composites was studied by the Py–GC/MS method.     

浅析桥式起重机啃轨原因及处理方法

对桥式起重机车轮啃轨的各种表现形式分别采取不同的处理方法,保证起重机的安全运转。     

Bactericidal activity of silver nanoparticles supported on microporous titanosilicate ETS-10

The bactericidal activity of Ag nanoparticles supported on microporous titanosilicate ETS-10 was investigated. The nanoparticles were prepared by ion exchange followed by in situ reduction with NaBH₄ and characterized using XRD, XPS, HRTEM, and UV techniques. The Ag nanoparticles immobilized on ETS-10 were found to be stable against leaching with a concentration in an aqueous phase of less than the World Health Organization (WHO) specified secondary minimum concentration level. In comparison with the as-synthesized ETS-10 and Ag-exchanged ETS-10 materials, the ETS-10 materials containing an optimum amount of Ag nanoparticles were observed to exhibit a significantly enhanced bactericidal activity and a longer lifetime towards microorganisms, such as Escherichia coli.     

Aqueous tape casting process for SiC

The condition for the preparation of stable SiC slurries by aqueous tape casting was identified. To acquire stable uniform slurries, the influences of dispersant, solid loading, sintering additives, binder and plasticizer on the rheological properties and viscosity were investigated. The conditions for preparing stable SiC slurries were studied and optimized. After tape casting and drying, the green SiC sheets showed smooth surface and homogeneous microstructure. The SiC ceramic can be densified to 98.89% after hot-pressing at 1850 °C (at 25 MPa in Ar for 30 min). The flexural strength, hardness, and toughness are 779.5 ± 39.2 MPa, 21.51 ± 0.70 GPa and 5.54 ± 0.26 MPa m^1/2, respectively. SEM shows a fine microstructure with few pores in the sintered samples. The fracture surface exhibited predominantly intergranular fracture type.     

上海地区地下工程专用混凝土的应用研究

耐久性混凝土的胶凝材料用量少,抗裂性高减少了后期修补费用,既满足耐久性要求,又兼顾绿色化。随着上海轨道交通和隧道工程的迅速发展,地下工程混凝土对耐久性的要求越来越高。本文简述了聚羧酸类外加剂配制的耐久性混凝土在上海地区地下工程的应用情况、存在的问题及解决方法。     

浅谈上海住宅社区地下车库的通风设计

地下车库已成为判定居住社区品质的重要考量,它能有效地解决居住的停车出行,保留社区的地面空间,提高社区的绿化率,提升土地资源的价值。随着土地资源的价值化,促使地下土地资源的深度开发,地下车库正在演化成二层或立体车库的形式,地下车库的通风排烟设计在所难免。文章针对地下车库的通风问题,用案例分析地下车库的通风设计应重视的相关细节。     

液化石油气储罐钢结构防晒（雨）棚防火保护

通过对液化石油气储罐火灾特点和钢结构防晒(雨)棚的耐火性能分析,提出了对液化石油气储罐钢结构防晒(雨)棚是否需要防火保护的观点,并结合实际情况,提出了具体的防火保护设计方案.     

钢筋混凝土梁屈服后残余变形特性研究

通过对钢筋混凝土梁单项循环逐渐加载试验,研究了粱屈服后残余裂缝宽度与残余变形、残余钢筋应变、频率、阻尼比的关系,试验表明,钢筋混凝土梁屈服后的残余变形、钢筋残余应变、频率、阻尼比与残余裂缝宽度呈规律性变化,据此绘制了钢筋混凝土梁损伤评价图.为实际工程中以简单易测的残余裂缝宽度作为综合反映变形、裂缝、钢筋应变、频率、阻尼比的性能指标对屈服后构件的损伤程度进行评价提供了理论依据.     

对“桩排距对双排抗滑桩内力的影响”讨论的答复

<正>非常感谢米占宽先生对发表于《岩土工程学报》2008年第7期的拙作"桩排距对双排抗滑桩内力的影响"(以下简称"原文")的关注及讨论,现对其提出的问题答复如下: