序列模式挖掘的两种典型算法及比较

序列模式挖掘是数据挖掘的重要分支,GSP算法与PSP算法是序列模式挖掘中的两种典型算法。本文介绍了这两种算法并对其进行了分析与比较。     

改善20CrMnTiH淬透性的研究

莱钢特钢厂20CrMnTiH钢材成分波动较大,淬透性带HRC8～10,范围较大,制约了齿轮钢质量的进一步提高.通过研究,发现铸坯中心偏析尤其是碳偏析为主要问题.通过工艺优化采取各项措施,尤其增加电磁搅拌后,中心碳偏析得到明显改善;C控制在0.19%～0.20%的炉次达到了95.6%;淬透性带控制在HRC6内的达到了92.1%;在HRC4内的达到了86.2%;提高了产品质量,满足了用户需求.     

单光子态的产生与测量

报道了通过自发参量下转换产生单光子态的实验研究,使用中心波长425 nm的飞秒脉冲泵浦Ⅰ类非共线相位匹配的BBO晶体,在实验上得到单光子计数率为2.978×10-4,并分析了实验中的相关问题.     

共轭斜量法在某些特征向量上收敛速度的估计

设 Ａ是对称正定矩阵，λ_1是 Ａ 的最大或最小特征值，χ_1是对应的特征向量．｛zk｝是用共轭斜量法求解方程组 Αχ＝ｂ时的近似解序列，ｅi＝Ａ～(_1)b-zi,本文给出了|x_1～Tei|较合理的上界估计式。从而为分析预处理共轭斜量法提供了进一步的理论基础。     

复注及多孔注浆理论研究

针对柱面注浆方式，研究了有关渗透注浆的单孔复注及不同方式布孔时多孔注浆的相互影响等问题，推导出一些有价值的岩体注浆理论公式，可用于指导现场注浆工程的设计与施工．     

Synthesis and structural characterization of novel,fluorinated poly(phthalazinone ether)s containing perfluorophenylene moieties

The synthesis and structural characterization of a series of novel, fluorinated poly(phthalazinone ether)s containing perfluorophenylene moieties are described. The monomers, 4‐(4′‐hydroxyaryl)phthalazin‐1(2H)‐ones ( 2a – 2d ), were conveniently and efficiently synthesized from phenols and phthalic anhydride in two steps via 2‐(4′‐hydroxybenzoyl)benzoic acids, which were first obtained by the Friedel–Crafts reaction in good yields and with high stereoselectivity and were then converted into 2a – 2d by fusion with hydrazine. All the polymers were prepared by nucleophilic aromatic substitution (S_NAr) polycondensation between the compounds perfluorobiphenyl and 4‐(4′‐hydroxyaryl)phthalazin‐1(2H)‐ones ( 2a ‐ 2d ). The resulting fluorinated polymers were readily soluble in common organic solvents (e.g., CHCl₃, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, N‐methylpyrrolidone, etc.) at room temperature. Their weight‐average molecular weights and the polydispersities ranged from (7.96–18.25) × 10³ to 1.31–2.71, respectively. Their glass‐transition temperatures varied from 213 to 263 °C. They were all stable up to 390 °C both in air and in argon. The 5% weight‐loss temperatures of these polymers in air and argon ranged from 393–487 to 437–509 °C, respectively. Wide‐angle X‐ray diffraction studies indicated they were all amorphous and could be attributed to the presence of kink nonplanar moiety, phenyl phthalazinone along the polymer backbone. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 925–932, 2004     

乳糖修饰壳聚糖微载体的制备及对培养肝细胞代谢活性的影响

液体石蜡作分散介质。戊二醛作交联刑，通过反相悬浮聚合制备了微米级的壳聚糖微载体．环氧氟丙烷活化后，乳糖进行修饰．用孔糖修饰的微载体进行原代大鼠肝细胞培养，利用相差显微镜对培养细胞进行形态观察，并测定肝细胞的代谢活性，结果显示，乳糖修饰壳聚糖微载体是一种优良的肝细胞培养支架．     

匹配问题实例空间和解空间结构

本文通过研究匹配问题的实例空间，匈牙利算法和解空间三者之间的关系，指出S实例空间的数目与问题复杂度之间的关系既不是充分也不是必要的，而如何对问题的解空间进行合理的分解才能是问题的关键。     

Time-resolved synchrotron X-ray study of crystalline phase transition in poly(aryl ether ketone ketone) containing alternated terephthalic/isophthalic moieties

Unique crystallization and melting behavior in poly(aryl ether ketone ketone) containing alternated terephthalic and isophthalic moieties were studied by time-resolved synchrotron x-ray methods. Recently, this material has been shown to exhibit three polymorphs (forms I, II, and III). In this work, we further investigated their distinctive thermal properties and found that form I is the dominating and the most thermally stable phase while form II is favored by fast nucleation conditions and is the least stable phase. On the other hand, form III represents a minor intermediate phase that usually coexists with form I and can be transferred from form II and to form I. Structural and morphological changes in form I have been followed by simultaneous wide-angle x-ray diffraction (WAXD)/small-angle x-ray scattering (SAXS) measurements during cold- or melt-crystallization and subsequent melting. In all cases, a larger dimensional change was found in the crystallographic a-axis than the b-axis during heating and cooling. This may be due to the greater lateral stress variation with respect to temperature along the a direction of the primary lamellae which is induced by either the formation of secondary lamellae or the preferential chain-folding direction in poly(aryl ether ketone ketone)s. During the phase transitions of form II ← III in the cold-crystallized specimen and form III ← I in the melt-crystallized samples, lamellar variables (long period, lamellar thickness, and invariant) obtained from SAXS remain almost constant. This indicates that the density distribution in the long spacing is independent of the melting in form II or III. For melt-crystallization, the corresponding changes in unit-cell dimensions and lamellar morphology during the annealing-induced low endotherm are most consistent with the argument that these changes are due to the melting of thin lamellar population. © 1995 John Wiley & Sons, Inc.