α 拓扑空间的乘积性

研究了由拓扑空间(X,T)诱导出的α-拓扑空间(X,Tα)中的α闭包、α内部、α边界,证明了Tα=Tαα,得到了α-拓扑空间的乘积性,研究了αT2-空间的一些性质.     

h TNF-α cDNA的酶切鉴定

本文对Sepharose 2B层析分离后的重组质粒pGEM-1用E CORI及HindⅢ限制性内切酶进行切割,电泳分析结果表明用Sepharose 2B层析分离的质粒纯度可满足于克隆片段的酶切图谱分析。     

α -卤代反应和历程分析及应用

卤代反应是一个重要而又特殊的反应，本文包括有机化学中常涉及的几个α-卤代反应．对反应原理、原因作出理论分析，解释理解上的难点，并指明易出错和易混淆的地方，简述了它们在合成上的应用．     

Human endothelial senescence induced by IL-1α in vitro

Interleukin 1(IL-1) is an important proinflammatory cytokine that causes pleiotropic effects. Vascular endothelial cells stimulated by IL-1α can lead to the inflammatory response. Reactive oxygen species (ROS) are also generated at the site of inflammation and serve as an important factor against foreign invader. Here we report that long-term stimulation of human vein endothelial cells with IL-1α can accelerate their senescence associated with β-galactosidase activity. The flow cytometric analyses showed that most of the induced cells entered G0-G1 phase. DNA damage was more severe in senescent cells by comet assay. The induced cells by IL-1α had higher levels of ROS and malonyldialdehyde (MDA), lower activity of antioxidant enzymes and lower capacity of total antioxidant systems than control, which led to cell damage and cell degeneration, that is to say, which contributed to cellular senescence. Our results gave a direct proof to a new hypothesis-"the inflammation hypothesis of aging" on cellular level, and also provided a basis for the study on anti-aging and aging-related diseases.     

Stereocontrolled organocatalytic synthesis of prostaglandin PGF2α in seven steps

Prostaglandins are hormone-like chemical messengers that regulate a broad range of physiological activities, including blood circulation, digestion and reproduction. Their biological activities and their complex molecular architectures have made prostaglandins popular targets for synthetic organic chemists for over 40 years. Prostaglandin analogues are widely used as pharmaceuticals and some, such as latanoprost, which is used to treat glaucoma, have become billion-dollar drugs. Previously reported syntheses of these compounds are quite lengthy, and every chemical step costs time and energy, generates waste and is accompanied by material losses. Using a new bond disconnection, here we report a concise synthesis of the most complex prostaglandin, PGF2α, with high levels of control of relative and absolute stereochemistry, and fewer steps. The key step is an aldol cascade reaction of succinaldehyde using proline organocatalysis to create a bicyclic enal in one step and an enantiomeric excess of 98%. This intermediate bicyclic enal is fully primed with the appropriate functionality for attachment of the remaining groups. Access to this bicyclic enal will not only render existing prostaglandin-based drugs more affordable, but will also facilitate the rapid exploration of related chemical structures around the ubiquitous five-membered ring motif, such as potentially therapeutic prostaglandin analogues.     

微晶态α -MnO2的界面合成及其催化性能

以KMnO4和KOH的混合溶液及Mn(NO3)2溶液为原料,采用CCl4/H2O界面法,通过改变锰盐、碱溶液、陈化时间及焙烧温度等条件,制备了系列MnOx催化剂.以邻二甲苯的分解率和二氧化碳产率综合评价了上述催化剂的活性,XRD,BET及SEM测试结果显示,陈化24 h及焙烧400℃条件下得到的催化剂为微晶态α-MnO2纳米颗粒,其比表面积为28.962m2/g.     

Smith补偿算法在OMRON C200Hα PLC中的实现

给出了利用OMRONC200HαPLC实现Smith补偿算法的方法.在PLC上编制Smith补偿算法应用程序时,可以利用PID控制指令,还要应用定点运算指令解决浮点数的计算问题.以铝合金厂工业电阻炉的炉温控制为工业应用背景,探讨了该实现方法的实用性.     

Modeling the hot working behavior of near-α tita nium alloy IMI 834

The hot working behavior of near-a titanium alloy IMI 834 with a duplex starting microstructure was studied using the technique of processing map.The processing map was interpreted in terms of the microstrucmral processes occurring during deformation,based on the values of dimensionless parameter η which represents the energy dissipation through microstructural processes.An instability criterion（ξ<0） was also applied to demarcate the flow instability regions in the processing map.Both the parameters（η and ξ） were computed using the experimental data generated by carrying out hot compression tests over a range of temperatures（850-1060℃） and strain rates(3×10^-4-1/s).The deterministic domains observed under the investigated temperature and strain rate conditions were attributed to continuous dynamic recrystallization or globularisation of a lamellae,dynamic recrystallization and growth of β grains through microstructural observations.An unified strain compensated constitutive equation was established to describe the hot working behavior of the material in the selected temperature-strain rate range.The established constitutive equation was validated using standard statistical parameters such as correlation coefficient and average absolute relative error.     

由复迭代模型 Z←Z~α C 得到的分形图

阐述了由复迭代模型Ｚ←Ｚα＋Ｃ生成分形图的方法和步骤，并对所得图形的某些性质进行了分析。     

A POLYNOMIAL CORRECTION TECHNIQUE USING RhKα COMPTON PEAK IN X-RAY FLUORESCENCE SPECTROMETRY

Compton scattering radiation of an X ray tube target line is widely used for matrix absorption correction in X-ray fluorescence analysis of heavy trace elements in light matrix samples,Compton scatter ing internal standard technique has been a routine method in geological samples since Reynolds recommended the method in 1963.     

Central powering of the largest Lyman-α nebula is revealed by polarized radiation

High-redshift Lyman-α (Lyα) blobs are extended, luminous but rare structures that seem to be associated with the highest peaks in the matter density of the Universe. Their energy output and morphology are similar to those of powerful radio galaxies, but the source of the luminosity is unclear. Some blobs are associated with ultraviolet or infrared bright galaxies, suggesting an extreme starburst event or accretion onto a central black hole. Another possibility is gas that is shock-excited by supernovae. But not all blobs are associated with galaxies, and these ones may instead be heated by gas falling into a dark-matter halo. The polarization of the Lyα emission can in principle distinguish between these options, but a previous attempt to detect this signature returned a null detection. Here we report observations of polarized Lyα from the blob LAB1 (ref. 2). Although the central region shows no measurable polarization, the polarized fraction (P) increases to ～20 per cent at a radius of 45?kiloparsecs, forming an almost complete polarized ring. The detection of polarized radiation is inconsistent with the in situ production of Lyα photons, and we conclude that they must have been produced in the galaxies hosted within the nebula, and re-scattered by neutral hydrogen.     

对称三取代的功能化α 环糊精衍生物的合成与表征

将α-环糊精6-位羟基进行选择性修饰,使之与过量的2-巯基吡啶在N,N-二甲基甲酰胺/碳酸钾体系中反应,合成了一种新的具有C3v对称的α-环糊精分子主体,并用核磁共振谱、电喷雾质谱等方法对其结构进行了表征.     

Overexpression of phospholipase Dα gene enhances drought and salt tolerance of Populus tomentosa

The cDNA of AtPLDα (Arabidopsis thaliana Phospholipase Dα) gene was introduced into P. tomentosa (Populus tomentosa) under the control of the Cauliflower mosaic virus 35S promoter. Southern and Northern blot analyses suggested that the AtPLDα gene has been transferred into the P. tomentosa genome. No obvious morphological or developmental difference was observed between the transgenic and wild-type (WT) plants. Drought and salt tolerance and gene expression of seedlings of several transgenic lines and WT plants (control) were studied. The results showed that the rhizogenesis rate and the average root-length of transgenic lines were significantly higher than WT plants after mannitol and NaCl treatment under the same growth conditions. Northern blot analysis indicated that the higher the PLDα expression in the transgenic plants, the more tolerant the transgenic plants are to drought and salt treatment. Meanwhile, another group of these transgenic lines and WT plants (control) were treated with PEG6000 and NaCl separately. The contents of chlorophylls and the activities of some anti-oxidant enzymes (superoxide dismutase, guaiacol peroxidase and catalase) as well as malondialde-hyde and relative electrical conductivity were analyzed. Altogether, our results demonstrated that overexpression of the PLDα gene can enhance the drought and salt tolerance in transgenic P. tomen-tosa plants.     

Study on the electronic structure of nickel hydroxide by quantum chemical DV-Xα calculation

The electronic structures of atom clusters NiTO12H12^2＋ and NiTO12H9^- of β-Ni（OH）2 were calculated by quantum chemical DV-Xα method. By analyzing the state densities, orbital populations, net charges and electric charge density differences of the selected clusters, it was indicated that β-Ni（OH）2was not typical ionic crystal, and the bonds between Ni and O atoms had obvious covalent characteristics. The bonds between H atom and other atoms in the crystal structure were weaker, which ensured that H atoms can easily deintercalate and intercalate into β-Ni（OH）2. The structure of β-Ni（OH）2 was not changed by moderate de-intercalation of H atoms. However, with the excessive de-intercalation of H atoms, the structure of β-Ni（OH）2 changed and the electrochemical active properties were reduced.