Nature of Intergranular Phase in Nonohmic ZnO Ceramics Containing 0.5 Mol% Bi2O3

The intergranular phase obtained by sintering a binary mixture of ZnO + 0.5 mol% Bi₂O₃ was isolated by using a dilute solution of HCIO₄, which etches ZnO preferentially. The combined results of selected-area electron diffraction and microscopy, microprobe analysis, and X-ray diffraction strongly indicate that the intergranular material is a polycrystalline phase of tetragonal β-Bi₂O₃ ( P 42₁ c ), rather than the amorphous ZnO-Bi₂O₃ phase reported earlier. It appears that the nonohmic behavior in this prototype metal-oxide varistor must be an interfacial property associated with the semiconducting ZnO grains separated by thin layers of high-resistivity Bi₂O₃.     

交-交变频传动的SVC系统的研制与效果评价

根据静止型无功补偿装置（SVC）的设计与装置投动后的调试、测试结果,阐述了SVC系统研制的基本思路与设计原理,进行了滤波、补偿效果的比较与评价,并总结了SVC的技术特点。     

Staphylococcus aureus Growth and Enterotoxin Production in Mushrooms

An enterotoxin A (SEA) producing strain of Staphylococcus aureus was inoculated onto mushrooms and incubated under simulated pre-and post-canning conditions. S. aureus grew and produced SEA in mushrooms incubated at 25°C in 10% to 20% NaCl. Growth and SEA production occurred when mushrooms were stored in plastic bags at 37°C, but not at 25°C. Mushrooms heat-processed at 121.1°C supported S. aureus growth and SEA production. No SEA was recovered from mushrooms inoculated with 1 or 10 ng SEA/g and heated at 121.1°C for 4.5 min. At higher inoculated SEA levels (100 and 1,000 ng/g), SEA was detectable after 10 min of heating. Staphylococcal enterotoxin could be present in canned mushrooms as a result of pre-, but more likely post-processing contamination.     

从先进核电厂仿真器到数字核电厂之现状与发展方向

进入21世纪后各种尖端科技进展很快,例如高性能计算能力、超高速网络、云平台等。本文探讨如何应用这些尖端科技,进行从先进核电厂工程仿真器往上提升成为数字核电厂之初期规划与发展方向。     

A Distribution Factor Method with Cubic Interpolationg Correction for Analysis of Building Frames

A more accurate approximating method for the analysis of building frames than the original distribution factor method described in Reference [7] is presented. The relative magnitudes of the joint displacements (w, α, β) on a particular floor are rather insensitive to the lateral load and are dependent largely on the local stiffness of the beams and columns of the floor of interest. These relative magnitudes are called distribution factors. The distribution factors corresponding to unit u, v, and θ displacements, respectively, can be determined floor by floor. The absolute magnitudes are then obtained by linear combination of the distribution factors. The coefficients of the linear combination are called the mixing factors. There are nine mixing factors per floor, three for each displacement (w, α, β) corresponding to unit u, v, and θ, respectively. The mixing factors are found after the lateral loads are imposed. This paper makes corrections on the displacements for very tall buildings where uneven elongations of columns along the height are important. A new distribution pattern in terms of cubic polynomials with an additional ten unknowns per floor is added to the original sets of distribution factors. The total number of unknowns per floor for a three-dimensional building is 22 (9 mixing factors + 10 coefficients of the cubic polynomial + 3 horizontal displacements u, v, θ) irrespective of the complexity. Less than 5% errors in the computed nodal displacements are achieved. The method is particularly suitable for microcomputers.     

无机-有机物包覆红磷的制备与应用研究

以红磷为囊芯,Mg(OH)2和聚氯乙烯为囊材,采用沉淀法制备无机-有机物包覆红磷(IOERP)。通过FESEM、XPS、TG等分析手段对其表征。结果表明:FESEM显示红磷表面包覆层均匀,XPS表明红磷表面包覆率达到97.18%,TG结果显示经包覆后的红磷着火点提高到430℃。以阻燃性能和力学性能为指标,考查红磷和IOERP对丙烯腈-丁二烯-苯乙烯塑料的阻燃和力学性能影响。测试结果显示:IOERP比红磷阻燃ABS的效果好,且力学性能有所提高。     

高温条件下混凝土爆裂机理研究进展

对高温条件下混凝土爆裂的研究进行了全面综述,总结了混凝土爆裂发生的影响因素、成因机理及实验和理论研究的进展状况.提出了热开裂和孔隙水(汽)压力的耦合作用是产生混凝土爆裂和不确定性的主要原因.温升诱致混凝土爆裂是一个复杂的非线性问题,建立一个兼顾材料科学和力学的理论体系是全面理解混凝土温升爆裂的根本途径.