Degradation of mechanical properties of structural reactor materials induced by formation of stress concentrators

The paper deals with the crack nucleation and stability in strain fields of stress concentrators (e.g. voids, gas bubbles, secondary phase precipitates). A general equation describes critical and subcritical crack length as a function of external (applied loading) and internal (stress concentrator type, normal traction, elastic properties of matrix, etc.) parameters. For the critical crack an analog of the Griffith criterion is found. The reduction of fracture stress due to different types of internal stress concentrators was evaluated.     

农用抗生素产生菌Streptomyce SN03菌株的诱变选育

以链霉菌SN03菌株为出发菌株,采用紫外线诱变结合微波诱变的处理方法,通过对致死率、正负突变率和活性最大提高率的测定,确定了紫外线和微波诱变的最适时间,结合对诱变菌株的传代稳定性测定,获得了高效菌株UV-1-W3,其发酵液的抑菌圈直径达到33.2mm,抗菌活性比出发菌株提高了30.20%。     

Non-standard cut classification of fuzzy sets

Several important non-standard cut sets of lattice-valued fuzzy sets are investigated. These are strong cuts, “not less” and “neither less nor equal” cuts. In each case it is proved that collection of all cuts of any lattice-valued fuzzy set form a complete lattice under inclusion. Decomposition theorem (representation by cuts) is proved for “neither less nor equal” cuts. Necessary and sufficient conditions under which two lattice-valued fuzzy sets with the same domain have equal families of corresponding cut sets are given.     

Geometric modeling of spatial constraints: objectives, methods and solid-modeling requirements

Robust Product Lifecycle Management (PLM) technology requires availability of informationally- complete models for all parts of a design-project including spatial constraints. This is the subject of the present investigation, leading to a new model for spatial constraints, the ``virtual solid', which generalizes a similar concept used by Sapidis and Theodosiou to model ``required free-spaces' in plants [14]. The present research focuses on the solid-modeling aspects of the virtual-solid methodology, and derives new solid-modeling problems (related to object definition and to object processing), whose robust treatment is a prerequisite for developing efficient models for complex spatial constraints.     

棉精梳技术的新发展

以德国特吕茨勒公司产TC01型精梳机生产线为例,分析了精梳机技术的新发展,指出TC01型精梳机速度高达500钳次/min时无明显振动,噪声小;其钳板采用铝镁合金,精确磨光钳口,确保喂入棉卷重量为80 g/m时能准确夹持;斜纹线凹槽表面的鼓形罗拉,使夹持更均匀;四上、四下的牵伸系统可独立控制,并适应重定量、大牵伸;同时,还分析了精梳条中短绒含量、落棉率对纱线条干、断裂强度、伸长率、毛羽、纱疵分级的影响。     

正确选用G02/G03的一种简易判别方法

基于笛卡尔坐标系中坐标平面表达方式的分析,对数控编程的圆弧切削指令G02/G03的选用提出了一种极易掌握、具有直观、有效、快速和可靠特点的简易判别方法。     

Unified full implication algorithms of fuzzy reasoning

This paper discusses the full implication inference of fuzzy reasoning. For all residuated implications induced by left continuous t-norms, unified α-triple I algorithms are constructed to generalize the known results. As the corollaries of the main results of this paper, some special algorithms can be easily derived based on four important residuated implications. These algorithms would be beneficial to applications of fuzzy reasoning. Based on properties of residuated implications, the proofs of the many conclusions are greatly simplified.     

富钛BaO-TiO2（Ti／Ba=4-4．5）系微波介质陶瓷

采用固相反应法制备了富钛BaTi4＋xO9＋2x（x=0．0-0．50）微波介质陶瓷，探讨了TiO2含量以及烧结温度对物相组成和介电性能的影响。在1300～1350℃烧结BaTi4＋xO9＋2x陶瓷即可达到约98％的相对密度。当x≤0．28时，BaTi4＋xO9＋2x陶瓷为BaTi4O9单相。随TiO2含量的增加，BaTi4＋xO9＋2x陶瓷从BaTi4O9单相逐渐转变成以BaTi4O9为主相，同时出现TiO2和Ba2Ti9O20相，并且随烧结温度提高，TiO2含量较多的试样中出现更多的Ba2Ti9O20相。随TiO2含量的增加介电常数逐渐增大，而Qf值呈下降趋势。Qf值从x=0．0时的约40000GHz逐渐降低至x=0．50时的15000GHz。     

Anisotropy in compressive strength and elastic stiffness of normal and polymer-modified asphalts

Anisotropy in the compressive strength and the elastic stiffness of normal hot-mix asphalt (HMA) and polymer-modified asphalt (PMA) were investigated experimentally. Two types of prismatic specimen with planes of compaction either normal to or parallel to the applied axial compression were used. Both axial and lateral principal strains were measured locally. Continuous monotonic loadings at a constant strain rate were axially applied to investigate the anisotropy in the compressive strength. Very small strain–amplitude cyclic stresses were also applied by means of another load-controlled apparatus to investigate the anisotropy in the elastic stiffness. The followings were found: (i) compressive strengths of both HMA and PMA are anisotropic in that the values for the vertical direction were significantly larger than those of horizontal direction; (ii) the small strain stiffness of both HMA and PMA are anisotropic with the vertical elastic Young׳s modulus being greater than the horizontal elastic Young׳s modulus; (iii) the elastic Young׳s modulus is stress level dependent, exhibiting a hypo-elastic behaviour; and (iv) the elastic Young׳s modulus becomes greater with the applications of the normal and the polymer-modified asphalt cement binders.     

基于PMM OR03＋EPl83探头组合的环境电场检测仪设计

摘要i提出了一种基于意大利PMM公司的PMM01103＋EPl83探头组合的新型环境电场测试仪的设计方案。硬件由主机和探头2大模块组成,主机利用LPC2478作为MCU,实现按键操作,屏幕显示,数据存储,数据处理运算等功能,并完成探头的测量数据接收。