三氟甲磺酸铜(Ⅱ)催化的苯乙烯基重氮乙酸甲酯和芳胺的插入反应

在三氟甲磺酸铜催化下,苯烯基重氮甲酯和苯胺(2)在多种溶剂下发生插入反应,主要产物是α,β-不饱和γ-氨基酸衍生物.以二氯甲烷为溶剂时,产物的区域选择性随2上取代基不同而发生变化.通过在铜催化剂中加入配体,可以获得低的对映选择性.     

An efficient algorithm for Pawlak reduction based on simplified discernibility matrix

Since the definition of attribute reduction based on classic discernibility matrix differs from that of it based on positive region, a new simplified discernibility matrix and the corresponding definition of attribute reduction were proposed. At the same time, it proves that the proposed definition is identical to its definition based on positive region. For computing simplified discernibility matrix, the indiscernibility relation, which is also called equivalence relation, should usually be calculated at first, so a new algorithm for computing equivalence relation was designed with radix sorting, whose temporal complexity is O(|C||U|). Furthermore, an efficient attribute reduction algorithm is proposed, whose temporal complexity and spatial complexity are cut down to max(O(|C|²|U′ _pos ||U′|,O(|U||C|)) and max(O(|C||U′ _pos ||U′|,O(|U|)) respectively. At last, an example is used to illustrate efficiency of the new algorithms.     

飞秒激光双光子微细加工技术及研究现状

飞秒激光双光子微细加工技术以其特有的高精度三维微加工优势,成为微型机械加工领域新的发展方向之一。介绍了飞秒激光双光子微细加工技术的原理和应用的现状。结合目前已有的微细加工技术,对双光子微细加工技术的特点加以评述。简要报道了利用飞秒激光双光子微细加工技术的一些研究进展。探讨了飞秒激光双光子微细加工技术今后的发展方向及其存在的基本问题。     

M(Fe,CO,Ni)ZrO2气凝胶超细粒子催化剂织构和结构热稳定性的研究

用超临界流体干燥（ＳＣＦＤ）法制备出高比表面纳米级ＺｒＯ２和Ｍ（Ｆｅ，Ｃｏ，Ｎｉ）／ＺｒＯ２气凝胶超细原粉．详细考察了其在空气中４５０℃焙烧后织构和结构的变化，表明ＺｒＯ２气凝胶原粉织构和结构的热稳定性较差，而添加铁、钴、镍的Ｍ／ＺｒＯ２气凝胶原粉织构和结构的热稳定性明显增强，稳定作用依钴、镍、铁次序增加．焙烧后所得的Ｍ／ＺｒＯ２气凝胶超细催化剂颗粒增长不大，颗粒间仍较大程度地保持着原有凝胶三维网络织构状态．与常规法制备的催化剂相比，其比表面积和孔体积高出甚多．     

光学纯的cis,cis-2,2''''-螺二氢茚-1,1''''-二醇和2,2''''-螺二氢茚-1,1''''-二酮的合成

以丙二酸二乙酯和苄氯为起始原料,通过改进拆分方法,成功地合成了光学纯cis,cis-2,2'-螺二氢茚-1,1'-二醇(e.e.≥99%)和2,2'-螺二氢茚-1,1'-二酮(e.e.≥98%),收率较高.     

无限时滞的随机泛函微分方程解的渐近性质

本文研究了无限时滞随机泛函微分方程解的存在唯一性,矩有界性的问题.利用Lyapunov函数法以及概率测度的引入得到了确保方程解在唯一、矩有界、时间平均矩有界同时成立的一个新的条件.推广了Khasminskii-Mao定理的相关结果.     

CdSe量子点荧光探针检测生活饮用水中的痕量六价铬

采用胶体化学方法合成还原性谷胱甘肽(GSH)稳定的Cd Se纳米量子点,所合成的Cd Se量子点对痕量的六价铬具有灵敏的荧光猝灭作用。以Cd Se量子点为荧光探针,建立一种简单快速测定生活饮用水中痕量六价铬的检测方法。在0.05~2.0μg·L-1范围内,Cd Se量子点的荧光强度变化值与生活饮用水中六价铬的含量呈线性关系,方法的检出限为0.01μg·L-1,样品测定的相对标准偏差小于5%,加标回收率在97~104%之间。该方法能够快速灵敏检测生活饮用水中的痕量六价铬,具有重现性好,定量准确灵敏等优点。     

PIEZOELECTRIC Pb(Zr, Ti)O3 MICRO-DEVICES FOR SCANNING FORCE MICROSCOPY AND ULTRA-DENSITY DATA STORAGE

In this paper we report two types of micro devices based on Pb(Zr, Ti)O₃ (PZT) thin films for improving the throughput of scanning force microscopy (SFM) or data storage using SFM. One is a piezoelectric cantilever array integrated with force sensor as well as z-actuator on each cantilever for parallel operation. The 125-μm-long PZT micro cantilever with a natural resonant frequency of 189 kHz has a high actuation sensitivity of 75 nm/V. Independent parallel images using two cantilevers of the array were obtained. The other is a novel micro-SFM device that is expected to replace the cantilever, the deflection detection unit, and the macro-fabricated scanner which is the bottle neck limiting the single probe acquisition rate. The bridge-structured device has shown a microscopy sensitivity of 0.32 nA/nm in vertical direction and actuation abilities of 70-80nm/±V in the lateral direction.     

蒸煮液中的水分对纸浆卡伯值在线测量的影响分析

本文结合制浆造纸工业,对水分进行了光谱定性分析,探讨了在制浆蒸煮过程中水分对纸浆卡伯值在线分析系统的影响,确立了在蒸煮液中木素浓度在线测量的合适波长,避开了在蒸煮液中的水分对测量结果的影响,为后续的研究工作打下了基础     

具有可变均压槽的气体静压推力轴承性能研究

具有可变均压槽的气体静压推力轴承,是作者提出的一种新结构轴承.本文建立了这种新结构轴承的性能计算方法,用有限差分法耦合求解气体静压推力轴承的雷诺方程和弹性薄片的变形控制方程,得到轴承的各项性能参数,并通过试验加以对比验证,计算结果与试验具有较好的一致性.结果表明该新型气体静压推力轴承的设计方案能够提高轴承的刚度.