Simultaneous Spectrophotometric Determination of Three Components Including Deoxyschizandrin by Partial Least Squares Regression

1IntroductionWuweizi is a traditional Chinese herb,usually usedto cure cough,asthma,neurasthenic,hepatitisetc.Theactive ingredients in wuweizi are5%-22%lignan,themain components of which include deoxyschizandrin,schizandrin andγ-Schizandrin.Forthe purpos…     

Host/guest complex of Me-β-CD/2,2-dimethoxy-2-phenyl acetophenone for initiation of aqueous photopolymerization: Kinetics and mechanism

Methylated-β-cyclodextrin (Me-β-CD) was used to complex the photoinitiator, 2,2-dimethoxy-2-phenyl acetophenone (DMPA), yielding a water-soluble host/guest complex. The comparative studies demonstrated that the Me-β-CD complexed DMPA exhibited a high photoreactivity identical to the uncomplexed DMPA, while the CD complex obviously influenced the products of primary photolysis of DMPA and the photopolymerization kinetics due to the steric effect of CD on the subsequent initiation reactions. The photopolymerization rate of acrylamide can be described by the equation: R_p=K[2a]^0.62[M]^1.37[I]^0.5[Me-β-CD]⁰. The mechanism of polymerization was also discussed.     

成型鼓的软极限保护

通过修改工艺配方,自动完成对成型鼓鼓肩位置极限的设定,并且该软极限的大小根据工艺参数的不同可以自动调整,最终达到了对成型鼓的保护,实际使用效果好.     

Stress analysis of spontaneous Sn whisker growth

Spontaneous Sn whisker growth is a surface relief phenomenon of creep, driven by a compressive stress gradient. No externally applied stress is required for the growth, and the compressive stress is generated within, from the chemical reaction between Sn and Cu to form the intermetallic compound Cu₆Sn₅ at room temperature. To obtain the compressive stress gradient, a break of the protective oxide on the Sn surface is required because the free surface of the break is stress-free. Thus, spontaneous Sn whisker growth is unique that stress relaxation accompanies stress generation. One of the whisker challenging issues in understanding and in finding effective methods to prevent spontaneous Sn whisker growth is to develop accelerated tests of whisker growth. Use of electromigration on short Sn stripes can facilitate this. The stress distribution around the vicinity and the root of a whisker can be obtained by using the micro-beam X-ray diffraction utilizing synchrotron radiation. A discussion of how to prevent spontaneous Sn whisker growth by blocking both stress generation and stress relaxation is given.     

Characteristics of Milk Powders Produced by Spray Freeze Drying

Skim and whole milk powders were manufactured at lab scale by spray freeze drying (SFD), using liquid nitrogen as the cryogen. The polydispersity of droplet/particle sizes was limited using an encapsulator nozzle to atomize the feed. Particle morphology was examined using a scanning electron microscope. Samples were compared with equivalent spray-dried powders in tests of wettability and dissolution in water. The spray freeze-dried powders were found to be highly porous, with a uniform structure of pores throughout the entire particles. When tested in water, SFD skim milk powders wetted roughly three times as fast as industrially spray-dried agglomerated skim milk powders and were observed to dissolve rapidly by breaking down into smaller particles.     

60Si2Mn合金钢发蓝泛红的分析研究

本文探讨了60Si2Mn合金钢发蓝原理，针对其膜层泛红问题，分析了热处理、表面前处理、发蓝及浸油等过程对发蓝质量的影响，由此采取了相应的技术措施，生产实践证明发蓝质量稳定，生产效率明显提高。     

小波包变换压缩与地震数据处理

探讨了地震数据经小波包变换压缩后对后续处理过程的影响,以及经过某些处理后的数据会对小波包变换压缩产生什么影响等问题。将小波包变换压缩地震数据的结果与快速傅里叶变换压缩地震数据的结果进行了对比,其结果表明:应用小波包变换压缩地震数据,有效信号的损失非常小,压缩比大于快速傅里叶变换的压缩比。在大批量地震数据处理中可以使用小波包变换压缩地震数据。     

论我国高校科技成果转化的制度建设

高校科技成果转化是当今世界各国政府、产业界、学术界共同关注的课题,也是世界经济与科技、教育相结合的成功经验.在以往对该问题的研究中,人们较多地关注技术创新,而新制度经济学的研究表明,技术创新与制度创新之间是一个交互决定的动态演进过程.制度创新在作为技术创新实现的前提条件的意义上,对技术创新起着先决性的决定作用.基于以上认识,我们有必要从一个新的视角对高校科技成果的转化进行研究,注重高校科技成果转化过程中的制度建设.     

镁钴铝类水滑石催化合成安息香甲醚

采用共沉淀法制备了镁钴铝类水滑石化合物(MgCoAl-HTLcs),并用 X 射线衍射、扫描电子显微镜、NH_3程序升温脱附等方法对 MgCoAl-HTLcs 进行了表征,并以 MgCoAl-HTLcs 为催化剂催化苯甲醛与甲醇反应合成安息香甲醚,研究了n(Mg):n(Co):n(Al)、催化剂用量、原料配比、反应温度、反应时间对合成反应的影响。表征结果显示,MgCoAl-HTLcs 的晶相完整,表面主要为弱酸、弱碱性。催化合成安息香甲醚的适宜条件为:MgCoAl-HTLcs 催化剂用量0.10 g(约为原料总质量的0.23%),n(Mg):n(Co):n(Al)=0.4:1.6:1.0,V(苯甲醛):V(甲醇)=3:50,反应温度50℃,反应时间150 min。在此条件下,苯甲醛的平衡转化率达77.49%,安息香甲醚选择性接近100%。为洁净合成安息香甲醚开辟了一条新的途径。