单壁碳纳米管薄膜光电器件研究

制备了单壁碳纳米管薄膜光电器件, 在偏压和激光器照射条件下可产生净光电流。分别研究了偏置电压、激光功率、照射位置对净光电流的影响。实验表明, 激光照射薄膜中点, 净光电流随着偏压的增大而增大, 随激光功率的增大而趋于饱和, 偏压为0.2 V, 激光功率为22.7 mW时, 净光电流达到0.24 μA;无偏压, 激光照射薄膜不同位置时, 净光电流值关于器件中心对称分布, 照射两端点输出最大光电流, 照射中点输出趋于“0”。经分析, 在偏压和激光照射薄膜中心位置的条件下, 器件因内光电效应可产生净光电流;在无偏压和激光照射的条件下, 因光热电效应可产生净光电流, 并建立了温度模型, 根据单壁碳纳米管的热电势特性推导出了净光电流与光照位置的关系, 其符合实验结果;内光电和光热电效应是光电流产生、变化的原因, 在偏压和激光照射的一般条件下, 净光电流应是两种效应的叠加结果。器件所具有的光电特性使其在光伏器件、光传感器有应用的潜力。     

独立成分分析与主成分分析在股票市场上的运用

展示了分析及认识金融市场结构的一种新方法.将这种方法实例应用在了股票指数CAC40的一篮子股票中,对股票价格走势进行分析,并将独立成分分析（ICA）方法与传统的主成分分析（PCA）方法进行了比较.     

切割那些事

正祝你生日快乐,祝你生日快乐,祝你生日快乐!吹蜡烛喽,噗!贝卡,是我生日哎,你一口气把蜡烛吹灭了,几个意思啊?乔乔,那个……我是太激动了,一不小心……这样吧,我来替你切蛋糕。你想切成几块呢?(夺过塑料刀)贝卡你辛苦了,切蛋糕就不用你代劳啦!数学制造出了各种奇异的数字模式,有意思的是,你可以通过几个大小一样的球,轻松地检验它们是否正确。如果你只是一个普通人,那么你可以使用橘子或弹珠;但如果你是一位无所不     

刺激响应性刚柔嵌段共聚物的自组装

刚柔嵌段共聚物是指刚性链段和柔性链段以共价键相连形成的共聚物。不仅由于刚性链段有序排列的特点使得其自组装行为更为丰富多样,而且刚性分子将优异的功能特性赋予到超分子组装体中,有望实现超分子材料的功能应用。这类嵌段共聚物在溶液中自组装形成的聚集体会对外界的刺激(例如pH、光、温度、化学添加剂等)敏感,产生聚集体形态的变化。本文选取了部分典型的具有刺激响应性的刚柔嵌段共聚物,介绍了其智能自组装行为,并对其良好的发展前景做了展望。     

氯桥连1-甲基-3-羧甲基咪唑镉一维配位聚合物：[Cd2(C6H8N2O2)2Cl4]n·3nH2O的合成及晶体结构

A metal-organic coordination polymer [Cd₂(C₆H₈N₂O₂)₂Cl₄]_n·3nH₂O[where C₆H₈N₂O₂ is ionic liquid, 1-carboxymethyl-3-methylimidazolium] 1 has been hydrothermally synthesized and characterized by X-ray diffraction single-crystal structure analysis. The complex crystallizes in orthorhombic, space group Aba2 with a=1.747 6(3) nm, b=1.933 6(4) nm, c=0.692 75(13) nm, V=2.340 9(8) nm³, M_r=700.96, D_c=1.989 g·cm^-3, μ(Mo Kα)=2.312 mm^-1, F(000)=1 368, Z=4, the final R=0.021 4 and wR=0.051 2 for 3 331 observed reflections (I>2σ(I)). Each Cd(Ⅱ) atom is in a distorted octahedral environment, surrounded by an uncommon symmetrical bidentate chelating carboxylato group and two pairs of bridging chloro ligands. Successive octahedra related by the c-glide of eration share edges to generate a one-dimensional polymeric structure. CCDC: 692298.     

具有正负系数的抛物中立型时滞偏微分方程解振动的充要条件

本研究了具有正负系数的抛物中立型时滞偏微分方程的振动性，获得了该方程所有解振动的克要条件，并用例子加以说明．     

Oxygen vacancy formation and migration in Sr- and Mg-doped LaGaO3: a density functional theory study

Oxygen vacancy formation and migration in La0.9Sr0.1Ga0.8Mg0.2O3-5 （LSGM） with various crystal symmetries （cubic, rhombohedral, orthorhombic, and monoclinic） are studied by employing first-principles calculations based on density functional theory （DFT）. It is shown that the cubic LSGM has the smallest band gap, oxygen vacancy formation energy, and migration barrier, while the other three structures give rise to much larger values for these quantities, implying the best oxygen ion conductivity of the cubic LSGM among the four crystal structures. In out calculations, one oxygen vacancy migration pathway is considered in the cubic and rhombohedral structures due to all the oxygen sites being equivalent in them, while two vacancy migration pathways with different migration barriers are found in the orthorhombic and monoclinic symmetries owing to the existence of nonequivalent O1 and 02 oxygen sites. The migration energies along the migration pathway linking the two 02 sites are obviously lower than those along the pathway linking the O1 and 02 sites. Considering the phase transitions at high temperatures, the results obtained in this paper can not only explain the experimentally observed different behaviours of the oxygen ionic conductivity of LSGM with different symmetries, but also predict the rational crystal structures of LSGM for solid oxide fuel cell applications.     

Proton capture reaction of ³³S in nova V1065 Centauri

Previous studies have shown that 33 S(p, γ) 34 Cl is the most important reaction that affects the abundance of 33 S in the product of nova nucleosynthesis. In this paper, a more accurate thermonuclear reaction rate of 33 S(p, γ) 34 Cl in the nova is calculated based on the newly measured 34 Cl nuclear resonance levels. The electron screening correction and the non-resonance and narrow-resonance contributions are considered. The calculations are also combined with the recent observational data of nova V1065 Centauri and show that the thermonuclear reaction rates of 33 S(p, γ) 34 Cl are significantly different in the improved method. Because these results can affect the isotopic ratio of sulfur in the nova ejecta significantly, we make an estimate of the values of 32 S/ 33 S and 33 S/ 33 S ⊙ , which can be used as a diagnostic tool for the novae.     

一种高选择性汞(Ⅱ) 吸附剂的制备和应用

利用两步反应法制备了溴联苯三酚红功能性硅胶(BPRSG),并通过静态平衡方法研究了该功能性硅胶对多种性质相近的金属离子的选择性吸附性能,考察了溶液pH值和搅拌时间对Hg?吸附率的影响。结果表明,在pH=7.0时,该固相萃取剂对Hg(Ⅱ)有特异的选择性吸附,可以实现与Pb(Ⅱ),Co(Ⅱ),Mn(Ⅱ),Zn(Ⅱ),Cu(Ⅱ),Cd(Ⅱ),Ni(Ⅱ)等金属离子的选择性分离,对Hg?的吸附平衡时间为30 min;最大吸附容量为4.80 mg/g。将该吸附剂制成微型固相萃取柱,用动态平衡法研究了柱流速、洗脱剂种类、洗脱速度和各种干扰离子对分离富集Hg(Ⅱ)的影响。在优化条件下,微柱对Hg?的最低富集浓度为10μg/L,富集倍率为170倍,柱容量为0.65 mg/g。20种常见离子不干扰Hg?的吸附,用1.0 mol/L醋酸即可洗脱Hg(Ⅱ),柱子可重复使用。将微柱用于环境水样中Hg?的固相萃取,回收率在95.5%～98.0%之间。     

HPLC-ELSD法测定银杏酮酯软胶囊中萜类内酯的含量

建立银杏酮酯软胶囊中萜类内酯含量的测定方法。采用HPLC—ELSD法,色谱条件为Diamonsil C18柱（250mm×4．6mm,5μm）,正丙醇-四氢呋喃-水（体积比l：25：74）为流动相,ELSD漂移管温度107％2,空气流速3．0L／rain。银杏内酯A、银杏内酯B、银杏内酯C、白果内酯分别在4．0088-20．0440,3．9284-19．6420,3．8348～19．1740,3．7888～30.3104gg范围内呈良好的线性关系,线性相关系数分别为0．9992,0．9999,0．9995,0．9998,回收率分别为98．48％,97．62％,97．54％,97．24％,测定结果的相对标准偏差分别为0．99％,1．13％,1．17％,0．83％（n=5）。该方法准确可靠,可用于银杏酮酯软胶囊的质量控制。