甘蔗良种化控加繁法初探

在江西省万安县蔗区，通过合理勤施重施氮肥和喷施植物生长调节剂，使加速繁殖的川糖79－701实现了10个月内两次采苗，最高繁殖倍数达60倍，证明霜冻蔗区也能通过“一年两采法”加速良种繁殖。     

Application of fuzzy and rough sets theory in the optimization of machining parameters for mold milling operations

NC milling operation has become one of the main means of mold manufacturing in recent years, and the determination of milling conditions is important to assure the quality and minimize the costs of molds. This paper first constructs an optimization model of machining parameters for mold milling operations, focusing on minimizing the production costs. Then, based on the properties of the machining parameters database, it also proposes an extended model of fuzzy and rough sets theory for incomplete information systems, including incomplete continuous attribute values, and applies the model to rules learning from the machining database. Thus, by rule reasoning, the feasible solution space of optimization model can be easily established. At last, an example is presented to detail the optimization of machining parameters in the case of the cavity milling of an injection plastic mold.     

热镀锌技术的发展及本钢连续热镀锌机组的装备水平

本文着重从现今世界连续热镀锌技术发展所采用的新工艺、新设备上对本钢热镀锌机组的装备水平进行分析，并论述了其在国内所处地位及与世界先进水平的差距。     

Potent pseudosubstrate-based peptide inhibitors for p60(c-src) protein tyrosine kinase

We recently reported the identification of GIYWHHY as an efficient and specific substrate for p60(c-src) protein tyrosine kinase (PTK) by screening a secondary random peptide library (Q. Lou et al., Bioorg. Med. Chem., 4: 677-682, 1996). Based on the primary structure of GIYWHHY, we designed and synthesized several pseudosubstrate-based peptide inhibitors. Some of these peptide inhibitors are highly potent and specific with IC50 in the low micromolar range. Because both YIYGSFK and GIYWHHY are efficient and specific substrates for p60(c-src) PTK, chimeric branched peptides based on these two sequences were synthesized. These branched peptides inhibit p60(c-src) PTK with high potency, indicating that the enzyme-active site of p60(c-src) PTK can accommodate more than a linear motif. This may explain why seemingly several peptides with very different linear structures can all be phosphorylated by this enzyme.     

Tensile behaviour of Fe3Al-based intermetallic alloy in the rolled state

Abstracts are not published in this journal This revised version was published online in November 2006 with corrections to the Cover Date.     

Stability of real-time lot scheduling policies for an unreliablemachine

A single-machine multiproduct manufacturing system with random breakdowns and random repair times is considered. Under a weak capacity condition on the system it is shown that the total work-in-progress (WIP) is a recurrent stochastic process. By replacing the stochastic model by a deterministic one with preventive maintenance activities scheduled on a regular basis or by strengthening the capacity condition, the boundaries of WIP and expected WIP, respectively, over time can be shown     

An investigation of the fatigue and fracture behavior of mn-containing gamma titanium aluminides

The fatigue and fracture mechanisms in Ti-48Al-xMn (x = 1.4 to 2.0 at. pct) gamma-based titanium aluminide alloys are elucidated. Unlike most gamma alloys, which fail predominantly by transgranular fracture at room temperature, fracture in ternary Ti-48Al-xMn alloys is shown to occur mainly by intergranular failure. The incidence of intergranular failure increased with increasing annealing duration and temperature. Intergranular fracture is shown to occur as a result of the segregation of Mn to equiaxed and interlamellar boundaries. Annealing either above or below the eutectoid temperature results in the precipitation of α₂ particles. The reduction in the strength and toughness of ternary Mn-containing alloys is attributed to the combined effects of segregation and α₂ precipitation. A micromechanics framework is presented for the assessment of twin toughening mechanisms under monotonie and cyclic loading. Formerly Staff Scientist with General Electric Research and Development, Schenectady, NY 12301 Formerly Undergraduate Student, Department of Materials Science and Engineering, The Ohio State University     

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本文通过X射线衍射技术对一些液体作用后的粘土矿物晶格变化作了测定,应用冷冻制样、不镀膜方法对样品处理前后进行对比扫描电镜观察。结合渗透率试验,进行了粘土矿物伤害油气层的研究,并对预防措施作了探索。     

Time-resolved study by X-ray powder diffraction with position-sensitive detector: rate of the β-Cs2Cdl4 transformation and the effect of preferred orientation

A time-resolved X-ray powder diffraction of the transformation, at room temperature, of the metastable β-Cs₂Cdl₄ phase into α-Cs₂Cdl₄ is described. It is based on data collected by means of a conventional X-ray diffraction system combined to a curved position-sensitive detector. The transformation is governed by a nucleation and a three-dimensional growth process, and its rate depends on the particle size and crystal imperfections. When particle sizes are less than 40 μm, the rate of the transformation strongly decreases in the later stage of growth, due to the stresses produced by structural modifications. Particular attention is paid to the fact that the quantitative interpretation of experimental data in kinetic terms, can be influenced by the existence of a preferred orientation effect of the crystallites in the sample.     

混合馏份油的裂解研究

在研究直馏汽油与轻柴油混合裂解的基础上,回归出计算乙烯产率的经验模型,用来预测混合裂解的乙烯产率,对工业生产有一定的指导意义。