变质量单面完整约束系统Lie对称性的摄动与广义Hojman型绝热不变量

研究变质量单面完整约束系统Lie对称性的摄动与广义Hojman型绝热不变量.首先通过一般无限小变换下的Lie对称性得到广义Hojman型的守恒量；然后基于力学系统高阶绝热不变量的定义，研究小扰动作用下系统Lie对称性的摄动，得到系统广义Hojman型绝热不变量；最后举例说明结果的应用. 关键词： 变质量 单面完整约束 对称性 摄动 绝热不变量     

Boom and bust in continuous time evolving economic model

We show that a simple model of a spatially resolved evolving economic system, which has a steady state under simultaneous updating, shows stable oscillations in price when updated asynchronously. The oscillations arise from a gradual decline of the mean price due to competition among sellers competing for the same resource. This lowers profitability and hence population but is followed by a sharp rise as speculative sellers invade the large un-inhabited areas. This cycle then begins again.     

Some predictions on ‘microscopic Hubble constant’ for the energies available at FAIR - GSI

The goal of this paper is to present some estimations of so-called 'microscopic Hubble constant' in the nucleus-nucleus collisions at the energies available at FAIR GSI, in the frame of CBM experiment. The analysis, based on the experimental data obtained in the previous nucleus-nucleus collisions at RHIC, indicated values of this constant of about 10²³s⁻¹ and ratios between the Hubble constant and 'microscopic Hubble constant' with the same magnitude as the ratio between the intensities of both interactions types involved. The UrQMD v 2.3 simulation code is used to generate events for Au-Au collisions at the energies of 5 GeV/u, 10 GeV/u, 15 GeV/u and 20 GeV/u and the Buda-Lund model is used for evaluation.     

氮化硅陶瓷烧结微结构演化的同步辐射CT实时研究

利用同步辐射CT (SR-CT)技术, 在氮化硅陶瓷样品烧结过程中对其进行实时投影成像, 并应用滤波反投影算法和数字图像处理技术, 得到了样品在整个烧结过程中内部微结构演化的二维和三维重建图像, 实现了对陶瓷固相烧结过程实时、无损的观测. 通过重建图像清晰观测到了陶瓷样品在烧结三个阶段中颗粒接触、烧结颈形成、晶粒和气孔长大、气孔球化并收缩等烧结现象; 统计了样品在不同烧结时刻的孔隙率, 得到了孔隙率随烧结时间对数的变化曲线, 并根据曲线分析了样品在不同烧结时刻致密化速率的变化, 得到了烧结中期孔隙率和时间对数的线性关系. 实验的结果和现有烧结理论相吻合, 并为进一步完善烧结理论提供了有效的实验数据.     

Taking Fingerprints of DNA Polymerases: Multiplex Enzyme Profiling on DNA Arrays

A novel screening approach based on an oligonucleotide‐addressing enzyme assay enables multiplexed simultaneous profiling of DNA polymerases in nanoliter volumes in terms of their different properties. This approach was used to identify enzymes with altered properties out of a library of protein mutants.

     

Moving domain walls in magnetic nanowires

This paper investigates the reversal of magnetic nanowires via a perturbation argument from the static case. We consider the gradient flow equation of the micromagnetic energy including the nonlocal stray field energy. For thin wires and weak external magnetic fields we show the existence of travelling wave solutions. These travelling waves are almost constant on the cross section and can thus be seen as moving domain walls of a type called transverse wall.     

Optimal time and space regularity for solutions of degenerate differential equations

We derive optimal regularity, in both time and space, for solutions of the Cauchy problem related to a degenerate differential equation in a Banach space X. Our results exhibit a sort of prevalence for space regularity, in the sense that the higher is the order of regularity with respect to space, the lower is the corresponding order of regularity with respect to time.      

Structural, textural and photocatalytic properties of quantum-sized In2S3-sensitized Ti-MCM-41 prepared by ion-exchange and sulfidation methods

In₂S₃ nanocrystallites were successfully encapsulated into the mesopores of Ti-MCM-41 by a two-step method involving ion-exchange and sulfidation. The X-ray diffraction (XRD) patterns, UV-vis absorption spectra (UV-Vis), high-resolution transmission electron microscopy (HRTEM) and N₂ adsorption-desorption isotherms were used to characterize the structure of the composite materials. It is found that the diameter of most In₂S₃ nanocrystallites is about 2.5 nm, less than the pore size of Ti-MCM-41. The In₂S₃ nanocrystallites inside the Ti-MCM-41 host show a significant blue-shift in the UV-vis absorption spectra. Under irradiation of visible light (), the composite material has much higher photocatalytic activity for hydrogen evolution than bulk In₂S₃. It can be explained by the effective charge-separation in the quantum-sized In₂S₃-sensitized Ti-MCM-41.     

Thermal decomposition of iron(VI) oxides, K2FeO4 and BaFeO4, in an inert atmosphere

The thermal decomposition of solid samples of iron(VI) oxides, K₂FeO₄·0.088 H₂O (1) and BaFeO₄·0.25H₂O (2) in inert atmosphere has been examined using simultaneous thermogravimetry and differential thermal analysis (TG/DTA), in combination with in situ analysis of the evolved gases by online coupled mass spectrometer (EGA-MS). The final decomposition products were characterized by ⁵⁷Fe Mössbauer spectroscopy. Water molecules were released first, followed by a distinct decomposition step with endothermic DTA peak of 1 and 2 at 273 and 248 °C, respectively, corresponding to the evolution of molecular oxygen as confirmed by EGA-MS. The released amounts of O₂ were determined as 0.42 and 0.52 mol pro formula of 1 and 2, respectively. The decomposition product of K₂FeO₄ at 250 °C was determined as Fe(III) species in the form of KFeO₂. Formation of an amorphous mixture of superoxide, peroxide, and oxide of potassium may be other products of the thermal conversion of iron(VI) oxide 1 to account for less than expected released oxygen. The thermogravimetric and Mössbauer data suggest that barium iron perovskite with the intermediate valence state of iron (between III and IV) was the product of thermal decomposition of iron(VI) oxide 2.     

Study on photodegradation of injection-moulded β-polypropylenes

The effects of UV irradiation on β-nucleated injection-moulded polypropylenes (β-iPP) have been studied at several structural levels. Commercially available isotactic polypropylene was modified by 0.03 wt.% β-nucleating agent based on N,N′-dicyclohexylnaphthalene-2,6-dicarboxamide. β-iPP specimens were injection-moulded using a processing set-up in which only mould temperature was varied. It was found that specimens consisted of a skin-core structure, which was strongly influenced by varying mould temperatures. The structural development consequently affected the specimen degradability as shown by wide-angle X-ray scattering, light microscopy and micro-infrared microscopy.