The large time behavior of strong solutions to a P1-approximation arising in radiating hydrodynamics

This paper is concerned with the study of the Cauchy problem to a multi-dimensional P1-approximation model. Based on a known global well-posedness (Danchin and Ducomet in J Evol Equ 14:155–195, 2014), in $$L^{2}$$-critical regularity framework the time decay rates of the constructed global strong solutions are obtained if the low frequencies of the data under a suitable additional condition. The proof mainly relies on an application of Fourier analysis to a mixed parabolic-hyperbolic system, and on a refined time-weighted energy functional. As a by-product, those time-decay rates of $$L^{q}$$–$$L^{r}$$ type are also captured in the critical framework.     

ToF‐SIMS and principal component analysis: Effect of film thickness on crystal surfaces of polymers

The effect of film thickness on the structural conformation of the surfaces of the amorphous state, edge‐on lamellae and flat‐on lamellae of a semiflexible polymer, poly(bisphenol‐A‐etheroctane), was investigated by time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) with the aid of principal component analysis (PCA). PCA results empirically indicate that a structurally regular polymer surface was obtained with the formation of the flat‐on lamellae from the amorphous state at a low degree of supercooling. A higher concentration of end group and cilium ion fragments, which are indicative of free chain ends, was observed on the edge‐on lamellar surfaces than on the amorphous and the flat‐on lamellar surfaces. This finding was attributed to the fact that the lateral surface of the edge‐on lamellae contains many growth fronts, leaving behind a large number of uncrystallized chain remnants on the surfaces. Structural disorder was facilitated on both edge‐on and flat‐on lamellar surfaces as the film thickness decreased. Hence, this PCA study offers new insights into the nonequilibrium nature of polymer crystals and the mechanism of polymer crystallization in thin and ultrathin films. Copyright © 2010 John Wiley & Sons, Ltd.     

Homoleptic Platinum(II) and Palladium(II) Organothiolates and Phenylselenolates: Solvothermal Synthesis,Structural Determination,Optical Properties,and Single‐Source Precursors for PdSe and PdS Nanocrystals

Homoleptic d⁸‐metal organothiolates and phenylselenolates [M(EC₆H₅)₂]_∞ (E=S, M=Pt 1 , M=Pd 2 , M=Ni 5 ; E=Se, M=Pt 3 , M=Pd 4 ) were prepared as crystalline solids under solvothermal conditions. Their structures were solved using powder X‐ray diffraction data. In each case, the EC₆H₅ (E=S, Se) ligand binds to two metal ions (M=Pt, Pd, and Ni) to form chain‐like structures with planar (in 1 ) or zig‐zag (in 2 , 3 , 4 , 5 ) conformations. The [M(SR)₂]_∞ complexes (M=Pt, R=4‐tert‐butylphenyl 6 ; R=2‐naphthyl 8 ; R=4‐nitrophenyl 10 and M=Pd, R=4‐tert‐butylphenyl 7 ; R=2‐naphthyl 9 ; R=4‐nitrophenyl 11 ) were prepared under similar solvothermal conditions. Based on the XPS binding energies and elemental analyses, complexes 6 , 7 , 8 , 9 , 10 , 11 have the same [M(SR)₂]_∞ formulation as 1 and 2 . The cyclic complex [Pd₆(SCH₃)₁₂] 12 was prepared as a crystalline solid by solvothermal annealing treatment of the amorphous precipitate. A chain‐like polymer structure is proposed for both [Pd(SC₁₂H₂₅)₂]_∞ 13 and [Pd(SC₁₆H₃₃)₂]_∞ 14 ; these polymeric chains self‐assemble to give layer‐like structures. Solid‐state diffuse reflectance spectra reveal that the optical band gap E_g (eV) of complexes 1 , 6 , 8 , 10 and of 2 , 7 , 9 , 11 are in the range of 2.10–3.00 eV and 2.10–2.63 eV, respectively, and 5 has the lowest E_g value (1.72 eV). Heating solid samples of 4 and 13 under solvothermal conditions afforded phase‐pure Pd₁₇Se₁₅ and PdS nanocrystals, respectively. Field‐effect transistors fabricated with a drop‐cast thin film made from Pd₁₇Se₁₅ nanocrystals prior treated with an ethanolic solution of 1‐hexadecanethiol displayed ambipolar charge transporting properties with hole and electron mobility being 7×10^?2 cm² V^?1 s^?1 and 6×10^?2 cm² V^?1 s^?1, respectively.     

Donor-acceptor organic sensitizers assembled with isoxazole or its derivative 3-oxopropanenitrile

A series of new donor-acceptor organic sensitizers LJ5-LJ7 assembled with isoxazole or its derivative 3-oxopropanenitrile was synthesized and used in dye-sensitized solar cells to study the effect of both π-spacers and anchoring groups on device performance. X-ray crystal structure analyses show planar arrangement of dithiophene and isoxazole fragments, providing an excellent π conjugation and hence the large electronic coupling between the triphenylamine donor and electron acceptor units. For the DSSC applications, the derived photophysical and photovoltaic properties revealed a lower η value of 1.06% (LJ7) and 2.41% (LJ5), and 3.30% (LJ7) for the dyes with rhodanine-3-acetic acid, cyanoacetyl group, and vinyl cyanoacetic acid as the anchor. Electrochemical impedance spectroscopy was used to determine the interfacial charge transfer process occurring in solar cells that employed different dyes.     

The heavy atom effect on photocleavage of DNA by mono-hydroxyl halogenated corroles

<正>DNA photocleavage properties of halogenated mono-hydroxyl corrole 1-5 were investigated.It was found that these corroles were able to photocleavage supercoiled pBR 322 DNA(SC) into nicked-circular DNA(NC).The activity of these corroles follows an order of 432≈15.The photosensitized singlet oxygen(Φ_△) quantum yield by these corroles also follows that same order,showing the photocleavage activity is related to the heavy atom effect of halogen atoms on corroles.     

Triterpenoids from Drypetes chevalieri Beille (euphorbiaceae)

The CH2Cl2/CH3OH (1/1) extract of the dried stem of Drypetes chevalieri Beille afforded two new triterpeno?ds named drypechevalin A (11-oxo-beta-amyrin-3beta-ylcaffeate) and drypechevalin B (3,7-dioxo-D:A-friedooleanan-24-al) along with five known compounds: lupeol, lupeone, erythrodiol, putranjivadione, friedelin. Their structures were established on the basis of spectroscopic analysis and chemical evidence.     

基于随机矩阵理论的股市网络拓扑性质研究

本文运用随机矩阵理论(RMT)和相关系数动态演化模型建立全球股指二次“去噪”相关系数矩阵,并采用阀值法构建全球股市网络,进而分析该网络拓扑结构特性和解释风险在网络中的传染效应。研究发现,全球股市网络呈现出“小世界”效应;在θ=0.1数量水平下,全球股市网络具有较强的鲁棒性。同时,英国和荷兰的股票市场风险传染对网络整体的冲击较大;股市网络中各个股市间的风险传染路径与相关国家经济实力相关联,体现出较强的同配性。     

Plastic deformation in cake consolidation

Cake filtration has a variety of applications in wastewater treatment by solid/liquid separation processes. In order to obtain the physical properties of the filter cake, a Compression-Permeability Cell (C-P Cell) can be used to examine the constitutive relationships among the solid compressive stresses, porosity and the specific filtration resistance. In this paper, a mathematical model is proposed to study the transient distribution of stresses, strains and void ratios in the confined cake of a C-P Cell under constant axial loads for dewatering. Simulations have been carried out using a plasticity model and the sensitivity analysis has revealed the possible contribution a finite plasticity can bring about the two types of cake examples with either medium or high compressibility.     

Theoretical study of aromaticity in small hydrogen and metal cation clusters X (X=H,Li, Na,K, and Cu)

Five cation clusters X (X=H, Li, Na, K, and Cu) with two possible isomers, i.e., regular trigonal structure (D_3h) and linear structure (D_∞h), have been investigated using four methods: B3LYP, B3PW91, MP2, CCSD(T) and basis set 6‐311+G(3df). The calculations show that only the regular trigonal structure (D_3h) is stable. The related neutral clusters X₃Cl (X=H, Li, Na, K, and Cu) are also investigated using two methods: B3LYP, MP2, and basis set 6‐311+G(3df). For H₃Cl species, there is no a stable structure to be found. For other four X₃Cl (X=Li, Na, K, and Cu) species, there are two stable isomers, for which the bidentate structures (C_2v‐1) [see Fig. 1 (d)] are global minima. According to the general criteria for aromaticity including resonance energy (RE) and nucleus‐independent chemical shift (NICS), the five trigonal isomers exhibit a higher degree of aromaticity. Molecular orbital analysis reveals that the five trigonal X(X=H, Li, Na, K, and Cu) isomers possess only σ‐aromaticity originating from s orbitals. For the Cu ring the d orbitals do not play a significant role in the electron delocalization effects. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007