耀变体S5 0716+714的混沌特性研究

长期观测显示,耀变体S5 0716+714具有复杂的光变行为.本文运用混沌理论,研究了S5 0716+714四个较大爆发阶段的射电、光学和X波段的光变曲线.分别计算了它们的关联维和Lyapunov指数.结果表明:1)光变曲线的关联维和Lyapunov指数都介于纯混沌系统与随机噪声之间;2)相轨迹是一个与Rossler吸引子相似的混沌系统,由于受到各种内在或外在因素的影响产生噪声,导致关联维和Lyapunov指数均比Rossler吸引子大,相轨迹出现紊乱.从这两个混沌判据上看,三个波段均表现出很强的混沌特性,因此推断S50714+716的光变是一个混沌现象.     

Regulation of Glucose Oxidase Activity through Interaction with Fullerene Derivatives

The 2‐(hydroxymethyl)pyridine modified C₆₀ (PY‐C₆₀) and methoxydiglycol modified C₆₀ (MDG‐C₆₀) are synthesized using Bingel‐Hirsch reaction and characterized by nuclear magnetic resonance (NMR) and mass spectra. PY‐C₆₀ and MDG‐C₆₀ can bind to glucose oxidase (GOx) and quench the fluorescence of tryptophan (Trp) residue in GOx through static mechanism. The conformation of GOx is disturbed after formation of complex with these fullerene derivatives. Kinetic analysis indicates that PY‐C₆₀ and MDG‐C₆₀ may affect the catalytic activity of GOx with a partial mixed‐type inhibition mechanism. In the plasma glucose concentration range (3.6–5.2 mmol·L^?1), PY‐C₆₀ may significantly accelerate the catalytic velocity of GOx, however, MDG‐C₆₀ exerts almost no obvious change to the initial velocity of GOx, suggesting that elaborate design of molecular structure of fullerene derivative is very important for regulating the biological activity of fullerene‐enzyme complex.     

Structural control of nanocrystal superlattices using organic guest molecules

We report a host-guest chemistry approach to controlling the structures of nanocrystal superlattices through a molecular inclusion process. Upon addition of an appropriate amount of guest molecules such as squalane, polyisoprene, and 4-cyano-4'-pentylbiphenyl into a nanocrystal suspension, the resulting nanocrystal superlattices adopted non-close-packed structures (e.g., from face-centered cubic to body-centered cubic) and changed their morphologies to form superparticles. Our mechanistic studies revealed that these guest molecules can strongly tailor the kinetic process in superlattice formation, resulting in the formation of non-close-packed nanocrystal superlattices. The insights gained in this study are not only important for making nanocrystal superlattices with desirable architectures but also open a new way of synthesizing novel organic/inorganic composite materials.     

一种新型阻燃抗熔滴共聚酯的合成及表征

双酚A与碳酸乙烯酯反应得到改性单体双(羟乙基)双酚A(BHEEB),BHEEB与对苯二甲酸、乙二醇及阻燃剂[(6-氧代-6H-二苯并[c,e][1,2]氧磷杂己环-6-基)甲基]丁二酸(DDP)通过无规共聚合成了一种新型阻燃共聚酯PBPET.用1H-NMR、ICP-AES对共聚酯的结构进行了表征,用热重分析(TGA)、氧指数(LOI)测定、垂直燃烧测试等对共聚酯的热稳定性、阻燃性和熔滴行为进行了研究.结果表明,BHEEB可以提高共聚酯的热稳定性,含5 mol%BHEEB与4.8 mol%DDP的共聚酯P4.8B5PET,其TGA测试中600℃下氮气氛残炭(wt6R00)可达18.0%.燃烧测试表明,P4.8B5PET的LOI值可达37.0,垂直燃烧达V-0级,并且改性单体BHEEB的引入还能有效地改善聚酯燃烧时的熔滴行为.     

Some constructions of biharmonic maps and Chen’s conjecture on biharmonic hypersurfaces

We give several construction methods and use them to produce many examples of proper biharmonic maps including biharmonic tori of any dimension in Euclidean spheres (Theorem 2.2, Corollary 2.3, Corollary 2.4 and Corollary 2.6), biharmonic maps between spheres (Theorem 2.9) and into spheres (Theorem 2.10) via orthogonal multiplications and eigenmaps. We also study biharmonic graphs of maps, derive the equation for a function whose graph is a biharmonic hypersurface in a Euclidean space, and give an equivalent formulation of Chen’s conjecture on biharmonic hypersurfaces by using the biharmonic graph equation (Theorem 4.1) which paves a way for the analytic study of the conjecture.     

Synthesis and crystal structures of two three-dimensional vanadium polyoxoanion-bridged macrocyclic metal complexes

The reactions of transition metal macrocyclic complexes [ML](ClO₄)₂ (L?=?5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, M?=?Ni, Cu) with NH₄VO₃ under hydrothermal conditions gave two coordination polymers, namely [NiL]₂[V₆O₁₇] and [CuL]₂[V₆O₁₇]. Single-crystal X-ray diffraction analyses indicated that the central Ni(II)/Cu(II) atom displays a distorted six-coordinate octahedral coordination geometry by coordination with four nitrogen atoms of L, and two oxygen atoms of [VO₄] tetrahedrons. Compounds [NiL]₂[V₆O₁₇] and [CuL]₂[V₆O₁₇] show three-dimensional structures, which are constructed through the connections of dodecanuclear [V₁₂O₃₂]^4? rings with [NiL]²⁺ in [NiL]₂[V₆O₁₇], and [V₈O₂₂] _n ^4n? chains with [CuL]²⁺ in [CuL]₂[V₆O₁₇], respectively, generating one-dimensional channels.     

Synthesis of Duloxetine Intermediate (S)-3-Chloro-1-(2-thienyl)-1-propanol with Liquid-Core Immobilized Candida pseudotropicalis 104

(S) -3-Chloro-1-(2-thienyl)-1-propanol was synthesized by the asymmetric reduction of 3-chloro-1-(2-thienyl)propanone with liquid-core immobilized Candida pseudotropicalis 104. The optimum time was 28?h for the re-cultivation of immobilized cells. The optimum film solvent for the liquid-core capsule was 0.3?% chitosan (M _w 1.0?×?10⁵). Conversion decreased with the increase of the liquid-core capsule diameter and with the addition of more substrates at the same reduction time. The immobilized cells show good reduction ability in a potassium phosphate buffer (pH 6.6~7.2). The material outside the spread speed of immobilized cells was not restricted when the shaking speed was higher than 160?r/min. Liquid-core immobilized cells can be reused 11 times. Compared with the batch reduction, the continuous reduction of 3-chloro-1-(2-thienyl)propanone in the membrane reactor with liquid-core immobilized cells as catalyst can relieve the inhibition from a high-concentration substrate. Conversion and enantiometric excess of (S)-3-chloro-1-(2-thienyl)-1-propanol reached 100?% and >99?% in a continuous reduction of 12?g/L 3-chloro-1-(2-thienyl)propanone for 10?days.     

光学系统受迫振动的激光测量方法

将激光信号与高帧频CCD结合,解决了光学系统中振动信号和激光信号之间的转换问题,不仅能够测量振动对系统光束指向稳定性的影响,而且能够得到振动信号本身的频率特性。利用该方法对振源为150 Hz和200 Hz两种条件下的光学系统受迫振动进行测量,得到了与输入信号相吻合的振动信号属性。通过实验与分析得知:时域振幅测量精度为6.25 m,频域分辨力为2 Hz,方法简便高效,测量结果准确,已应用于角多路准分子激光主振荡功率放大器系统打靶试验平台光束指向稳定性的研究中。     

About a nonadditivity of energy and entropy

The mathematical expression of nonadditivity X(1 ?? 2) = X(1) + X(2) + ??X(1)X(2) has been frequently used for the development of statistical physics for nonadditive system, where X is entropy or energy, and ?? is hoped to be a parameter characterising the nonadditive property of the composite system (1 ?? 2). Here we show that this relationship cannot hold exactly. In general, ?? in this expression inevitably depends on how a given system with constant X(1 ?? 2) is divided into subsystems 1 and 2. Hence mathematical problems may arise when it is used to characterise the nonadditivity of the system. Nevertheless, under some conditions, it is possible to use it as a good approximation.