花生中丁酰肼残留测定的两种衍生方法比较

对气相色谱-质谱联用法(GC-MS)测定花生中残留丁酰肼含量时,衍生化所用的两种衍生试剂,水杨醛和2-硝基苯甲醛,在衍生反应的介质及条件、检测响应值、标准曲线的线性范围以及测定下限和回收率等方面作了详细比较.试验结果表明:两种试剂均适合作为衍生试剂,但从衍生反应操作简便以及较高的灵敏度和较好的回收率等方面考虑,用水杨醛作衍生试剂效果更好,而且在衍生化过程中用离心法除去反应而残留的水杨醛更保证了检测的精密度.应用这一方法所测得丁酰肼的测定下限(10S/N)为0.005 mg·kg-1,用标准加入法测得的回收率在98.0%～99.4%之间,测定值的相对标准偏差(n=6)在1.5%～3.6%之间.     

模糊形式背景下的类近似算子

分别在形式背景和模糊形式背景下定义类下近似算子和类模糊下近似算子,并研究它们的性质.证明这两种算子分剐等价于形式背景和模糊形式背景下的*算子和模糊*算子.进一步给出类下近似算子与类模糊下近似算子的公理刺画.最后,对偶地讨论类上近似算子和类模糊上近似算子的定义和性质.     

Design,Synthesis and Antitumor Activity of Novel Indolin-2-one Derivatives Containing 4-Thiazolidinone Moiety

A series of novel indolin-2-one derivatives containing 4-thiazolidinone moiety(7a―7r) were synthesized and evaluated for their in vitro antitumour activities against MDA-MB-231(human breast cancer), H460(human lung cancer) and HT-29(human colon cancer) cell lines by standard 3-(4,5-dimethylthiazae-2-yl)-2,5-diphenyltetrazo- lium bromide(MTT) assay. Representative compounds(7d, 7k, 7m, 7p) with higher cytotoxicity were further examined against one normal cell line(WI-38, human fetal lung fibroblasts). The preliminary investigation shows that most of the compounds display moderate to excellent potency and high selectivity against different human cancer cell lines. In particular, the most potent compound 7m shows promising cytotoxicity against MDA-MB-231, H460 and HT-29 cell lines with IC₅₀ values of 0.78, 0.056 and 0.018 μmol/L, respectively. The potency is much higher than that of Sunitinib(IC₅₀=3.46 μmol/L against MDA-MB-231, IC₅₀=2.59 μmol/L against H460, IC₅₀=1.50 μmol/L against HT-29) by 4.4, 46.3 and 83.3 fold.     

Effects of Donor and Acceptor on Optoelectronic Performance for Porphyrin Derivatives: Nonlinear Optical Properties and Dye-sensitized Solar Cells

Typical asymmetric donor-π-bridge-acceptor(D-π-A) zinc porphyrin dyes have been synthesized, and further modified by reacting the ethynyl groups of them with click reagent through a formal [2+2] click reaction. The electronic interaction between the push and pull electronic groups and the click reaction process were investigated by UV-Vis absorption spectroscopy. The nonlinear optical(NLO) properties of the dyes were studied by the Z-scan technique and clearly reverse saturable absorption to saturable absorption(RSA-SA) transition could be observed through click reaction of the dyes with TCNE. Furthermore, the photovoltaic properties of these porphyrin dyes were reaso- nably explained by the J-V curve fitting based on the equivalent-circuit model as well as the comparison between the absorption and incident-photon-to-current-conversion efficiency(IPCE) spectra. Besides, these dyes with different donors or acceptors could self-assembly into different microstructures by phase transfer methodology.     

轮对结构柔性对车轮辐板疲劳寿命的影响

针对高速动车非轴对称车轮辐板区域随机疲劳寿命问题,分别将轮对视为刚性体和柔性体建立了车辆-轨道系统动力学模型,仿真得到载荷时间历程和轮轨接触点在踏面上的位置时间历程。在三维有限元模型中使用约束方程模拟轮轴过盈配合,使非线性问题线性化,采用准静态叠加法得到应力时间历程。基于临界距离法中的点法,以疲劳破坏临界平面上的正应力为主循环计数参数,剪应力为辅助计数参数进行多轴循环计数,结合Spagnoli法和Miner理论研究了轮对结构柔性和车轴刚度对车轮辐板随机疲劳寿命的影响。研究结果表明,轮对结构柔性对车轮辐板疲劳寿命有较大影响。随着车轴刚度的降低,轮轨接触横向力的幅值显著增大,轮对模态的特征频率和车轮辐板区域的寿命降低。因此,在轮对轻量化设计时,需综合考虑车轴的结构刚度。     

二维磁性系统和准一维磁性纳米管的内能

采用量子统计理论的多体格林函数法计算二维单离子各向异性海森伯铁磁体、反铁磁体以及单壁铁磁纳米管的内能,对比铁磁体和反铁磁体的结果.在相同的参量下,反铁磁能量总是低于相应的铁磁能量(相变点除外).由于反铁磁能量随温度上升的速度较铁磁能量快,当温度升高到居里点T_C和奈尔点T_N时(T_C=T_N),铁磁能量和反铁磁能量相等.横向关联效应对系统内能的影响较大,不能忽略.     

Influence of Hyperon-Hyperon Interaction on Properties of Hadronic Star

The influences of hyperon-hyperon interaction on the overall properties of hadronic star are investigated in the framework of relativistic mean field （RMF） theory. For certain hyperon coupling, the weaker hyperon-hyperon interaction can lead to the heavier hadronic star, which accords with the observation of heavy neutron star in X-ray binaries. We find that the threshold densities of the hyperons with larger masses are brought to a lower values with the increase of the hyperon-hyperon interaction. The possibility of the existence of hyperon star is checked with the consideration of hyperon-hyperon interaction.     

荧光光谱法结合分子对接研究人血清白蛋白 对齐墩果酸与熊果酸的异构体识别作用

五环三萜化合物齐墩果酸(OA)与熊果酸(UA)为同分异构体,具有相似的理化性质和稍有差异的药理活性。目前人们主要采用各种色谱、质谱类方法实现对OA与UA的异构体识别,未见使用荧光光谱法的报道。提出了一种使用荧光猝灭法实现对OA与UA异构体识别的方法。首先考察了两种常见的血清蛋白-牛血清白蛋白(BSA)与人血清白蛋白(HSA)同OA与UA的作用情况,结果表明OA与UA均可有效地猝灭BSA与HSA的荧光发射。对所得荧光猝灭数据计算可知OA,UA与BSA,HSA作用的双分子猝灭速率常数(K_q)均远大于生物大分子荧光猝灭所观察到的最大散射碰撞速率常数2.0×1010 L·(mol·s)-1,说明猝灭类型均为静态猝灭,即OA与UA均是通过与BSA及HSA形成稳定复合物方式实现荧光猝灭的。应用双对数方程对所得荧光猝灭数据计算可知OA,UA与BSA,HSA所形成的复合物中结合位点数在0.90～1.26之间,说明所形成的复合物为1∶1型。BSA与OA,UA所形成复合物的表观结合常数(K_A)为同一数量级,相差不大,但是HSA与OA,UA所形成复合物的K_A差别很大,HSA-UA复合物的KA比HSA-OA复合物高124.91倍,表明HSA-UA复合物的稳定性更强。同步荧光实验结果显示,OA与UA的加入对于HSA波长差(Δλ)为60 nm同步荧光光谱的影响大于Δλ为15 nm的同步荧光光谱,由此可以说明OA与UA在HSA上的结合位点可能位于Trp残基附近。分子对接模拟计算结果表明OA与UA均对接在HSA结构中一个疏水性空腔中,主客体之间存在强烈的氢键与疏水作用。OA同Arg218,His242,Pro447等残基间存在氢键作用,键长分别为2.95,2.97与3.17 Å,此外还与Lys195,Lys199,Trp214,Arg222,Leu238,Asp451和Tyr452等七个氨基酸残基间存在疏水作用。UA同Trp214,Arg218和Lys444等残基存在氢键作用,键长分别为3.01,2.88与2.65 Å,此外还与Leu198,Gln221,Arg222,Asn295,Val343,Pro447,Cys448,Asp451和Val455等9个氨基酸残基间存在疏水作用。由于UA同HSA作用位点数目多于OA,说明UA与HSA疏水性空腔的空间匹配程度更高。因此,认为HSA-UA与HSA-OA复合物间稳定性差异是HSA实现对OA与UA异构体识别的原因。     

Liquid–liquid extraction of neodymium (III) and europium (III) using synergic mixture of furosemide and tribenzylamine in benzyl alcohol

The extraction behavior of Nd(III) and Eu(III) with 0.05 mol dm⁻³ furosemide in benzyl alcohol as single acidic extractant and then with equimolar (0.05 mol dm⁻³) synergic mixture of furosemide as acidic extractant and tribenzylamine as neutral donor in benzyl alcohol has been studied from aqueous solutions of pH 1 to 6. The effect of various parameters and of various cations and anions on the extraction of these metal ions was investigated. The composition of the extracted adducts was determined by slope analysis method that came out to be [(M(FS)₂)⁺ (CH₃COO)⁻] and [M(FS)₃·3TBA] where M = Nd(III) and Eu(III).

     

双核茂金属催化剂的合成、表征与应用

使用桥连配体锂盐与MCl₄络合, 合成了4个不同结构的双核茂金属化合物[μ,μ-(CH₂)₃]{[C(H)·(η⁵-C₅H₄)(η⁵-C₁₃H₈)](MCl₂)}₂[M=Zr or Ti](4, 5)和[μ,μ-(CH₂)₃]{[C(H)(η⁵-C₅H₄)(η⁵-C₉H₆)]·(MCl₂)}₂[M=Zr or Ti](6, 7), 配体和化合物都经过核磁氢谱(¹H NMR)、 碳谱(¹³C NMR)、 红外光谱(IR)及元素分析等表征, 确认了化学结构. 以甲基铝氧烷(MAO)为助催化剂, 化合物4~7为催化剂催化丙烯聚合, 考察了聚合温度、 乙烯压力、 铝钛或铝锆比对催化剂活性及聚合物分子量的影响. 结果表明, 多亚甲基桥连双核茂金属是高活性乙烯和丙烯聚合催化剂, 乙烯聚合活性最高达到7.5× 10⁶ g PE/(mol Zr·h)(化合物6), 丙烯聚合活性达 10 × 10⁵ g sPP/(mol Zr·h)(化合物4). 所得间规聚丙烯(sPP)的间规度指数(SI, r) 达到90%. 在同样条件下, 双核化合物的催化活性、 聚合物分子量M_w(> 100000)以及分子量分布(MWD>2.5)均比相应的单核化合物高(M_w<70000, MWD≤2), 表明该体系中存在较强的核效应.