Cycloviolaxanthin (= (3S,5R,6R,3′S,5′R,6′R)-3,6:3′,6′-Diepoxy-5,6,5′,6′-tetrahydro-β,β-carotin-5,5′-diol), ein neues Carotinoid aus Paprika (Capsicum annuum)

Cycloviolaxanthin (= (3S,5R,6R,3′S,5′R,6′R)-3.6:3′,6′-Diepoxy-5,6,5′,6′-tetrahydro-β,β-carotene-5,5′-diol), a Novel Carotenoid from Red Paprika (Capsicum annuum) From red paprika (Capsicum annuum var. longum nigrum) cycloviolaxanthin was isolated as a minor carotenoid and, based on spectral data, assigned the symmetrical structure 8 .     

Confirmation of the Absolute (3R,3′S,6′R)‐Configuration of (all‐E)‐3′‐Epilutein

Circular dichroism (CD) spectroscopy was used to distinguish between the isomeric (all‐E)‐configured 3′‐epilutein ( 2 ) and 6′‐epilutein ( 8 ) to establish the absolute configuration of epilutein samples of different (natural and semisynthetic) origin, including samples of 2 obtained from thermally processed sorrel. Thus, the CD data of lutein ( 1 ) and epilutein samples ( 2 ) were compared. Our results unambiguously confirmed the (3R,3′S,6′R)‐configuration of all epilutein samples. Compound 2 was thoroughly characterized, and its ¹³C‐NMR data are published herewith for the first time.     

LaH分子的X1∑+态的势能函数

应用原子分子反应静力学原理导出LaH分子的电子状态和可能的离解极限,考虑相对论紧致有效势RCEP(RelativisticCompactEffectivePotential)近似下,用QCISD方法计算了LaH分子基态X1∑+的平衡几何Re和离解能De为2.125A和2.623eV,并在计算出来的一系列单点势能基础上,用正规方程组拟合Murrell-Sorbie(M-S)势能函数,得到相应态的解析势能函数,由此计算对应的光谱参数,其Be、ae、ωe和ωexe的理论值,分别为:3.7333、0.0723、1461.73和21.383cm-1.     

高维分层混合模糊系统的规则缩减及逼近性假设检验

混合模糊系统,即通过调控参数将Mamdani和T-S合并建立的一种新型系统模型.混合模糊系统不仅能保持各自模糊系统的优良特性,还可大大缩减系统内部的模糊规则总数.为避免因增加输入变量引发高维混合模糊系统规则爆炸,基于混合模糊系统的分层表示,给出了分层混合模糊系统对连续函数的逼近算法.对比发现,高维分层混合模糊系统的规则总数可被大幅度削减.此外,通过实例模拟了一个三维混合模糊系统分层后的实际输出,并用统计学的t-假设检验方法检验了该分层混合模糊系统的逼近性能.     

The Law of the Iterated Logarithm and Central Limit Theorem for L-Statistics

The Chung–Smirnov law of the iterated logarithm and the Finkelstein functional law of the iterated logarithm for empirical processes are used to establish new results on the central limit theorem, the law of the iterated logarithm, and the strong law of large numbers for L-statistics with certain bounded and smooth weight functions. These results are used to obtain necessary and sufficient conditions for almost sure convergence and for convergence in distribution of some well-known L-statistics and U-statistics, including Gini's mean difference statistic. A law of the logarithm for weighted sums of order statistics is also presented.     

Analysis of carotenoids in the fruits ofAsparagus falcatus: Isolation of 5,6-diepikarpoxanthin

Summary In an investigation of carotenoids present in the fruits ofAsparagus falcatus capsanthin (1), capsorubin (2), 5,6-diepikarpoxanthin (7), capsanthin 5,6-epoxide (18), capsochrome (17), mutatoxanthin (19), antheraxanthin (11), and capsanthone (20) (Figure 1) have been isolated by preparative CLC and characterized by spectroscopic methods. On the basis of spectroscopic data the absolute configuration of 5,6-diepikarpoxanthin (7) was determined as 3S,5S,6S, which is identical with that occurring in samples originating from paprika andLilium. Presented at Balaton Symposium on High Performance Separation Methods, Siófok, Hungary, September 1–3, 1999     

聚四氟乙烯及其复合材料的转移与磨损

本文对聚四氟乙烯(PTFE)的分子特征与结构特性、PTFE的转移行为及对其磨损的影响、影响转移膜生成的因素、PTFE转移膜与底材相互作用的本质,转移膜剥落形成磨屑的考察、PTFE结晶度对粘着磨损及摩擦的影响和PTFE基复合材料的特性及其摩擦学性能等进行了综述介绍。     

计算有机粘结固体润滑涂层配方的计算机程序——Ⅰ.计算粘结剂与固体润滑剂比例的程序

作者介绍了填料在粘结涂层中随机紧密填充的物理模型及数学模型,并且根据这一模型、固体润滑剂的粒度分布、油吸附体积和粘结剂与固体润滑剂的密度,编制了计算粘结固体润滑涂层内有机粘结剂与固体润滑剂最佳配比的计算机程序。文章对这些程序及使用和计算结果作了简明的介绍,同时还对固体润滑剂在涂层中的分布及其对涂层摩擦磨损的影响进行了讨论。     

铁氧化物催化类Fenton反应

高级氧化技术是当今水处理技术领域研究的热点,Fenton试剂因操作简单、反应条件温和及氧化效率高等优势而备受关注。铁氧化物催化类Fenton反应能有效地解决催化剂回收利用难等问题,并且能够在较为广泛的pH范围内使用,从而成为Fenton氧化领域一个新的研究方向,但反应过程和机制往往更为复杂。本文评述了铁氧化物催化类Fenton反应中可能存在的多种机理,主要是羟基自由基理论、氧空位机理和高价态铁络合物机制。类Fenton反应速率的限速步骤是Fe(Ⅲ)/Fe(Ⅱ)循环过程,从提高反应速率的机理出发,本文探讨了类Fenton反应中铁氧化物催化剂的制备和发展,催化剂中多种价态的铁元素,通过相互间发生电子转移以加速Fe(Ⅱ)的再生,提高反应效率。铁氧化物掺杂过渡金属能显著提高催化H2O2有效分解的活性。阐明了多金属掺杂铁氧化物中多金属组分的催化机制和铁氧化物结构形态对反应性能的影响。研究表明催化剂中铁的结构形态、催化剂比表面积、催化剂与H2O2之间电子转移速率等都是决定催化剂性能的重要因素。最后讨论了继续研究方向,为开展非均相类Fenton反应提供参考。     

石油钻井底部钻具组合大挠度三维分析

精确描述了石油钻井底部钻具组合在三维弯曲井眼中的变形约束条件及边界条件，应用加权余量法，对底部钻具组合静力大挠度问题进行了三维分析研究，并编写了相应的计算机分析程序。该程序可以在普通微机上运行，能迅速模拟计算底部钻具组合任一点的挠度、转角和内力，同时求得钻头对地层的机械作用力和偏转角。通过算例分析，本文初步阐明了井眼曲率及方程中的非线性项对钻头力学特性的影响效果。