维吾尔语句子边界识别算法的设计与实现

本文分析维吾尔语的句子结束形式,研究维吾尔语句子边界规则,给出了句子划分思路,并实现了维吾尔语句子边界识别算法及程序.在对大量手工划分句子语料进行统计测试结果表明,该句子边界识别程序准确率超过98.7%.维吾尔语句子边界识别的研究对实现维吾尔语词性标注系统、维吾尔语句法分析器、机器翻译等众多领域有着很高的实际意义.     

Synthesis of α- and β-FeOOH iron oxide nanoparticles in non-ionic surfactant medium

Forced hydrolysis of Fe(III) ions in acidic media was performed under controlled synthetic conditions to produce α- and β-FeOOH iron oxides. The forced hydrolysis synthesis was carried out, separately, in an aqueous medium and the lamellar lyotropic liquid crystalline phase of a commercial non-ionic surfactant/water system. The FT-IR analyses confirmed formation of α- and β-FeOOH iron oxides in the aqueous and the surfactant media with slight formation of ferrihydrite and haematite. TEM micrographs have shown that particles formed in the lamellar lyotropic phase are smaller than those produced in the aqueous medium with their smallest size dimension being constrained in the nanometre scale with a size ranging between 5 and 100 nm. Particles produced in the nanoscale size appeared to have different optical properties compared to their counterparts produced in the microscale size.     

Stationary distribution and extinction of a stochastic SIRI epidemic model with relapse

In this paper, we study the dynamics of a stochastic Susceptible-Infective-Removed-Infective (SIRI) epidemic model with relapse. By constructing a suitable stochastic Lyapunov function, we establish sufficient conditions for the existence of an ergodic stationary distribution to the model. Moreover, sufficient conditions for extinction of the disease are also obtained.     

Preparation of polybenzidine submicrorods with controllable morphology using poly (ethylene oxide)-b-polystyrene as a template and its electrochemical properties

Polybenzidine (PBz) particles were formed by the chemical polymerization in micelles of block copolymer by using Poly (ethylene oxide)-b-Polystyrene [PEO₁₁₃-b-PS_x (x = 50, 58 and 100)] as templates. The samples were characterized by IR, UV-vis absorption spectroscopy, transmission electron microscopy, cyclic voltammetry, constant current charge-discharge and electrochemical impedance to determine their morphologies and electrochemical properties. The results show that the prepared PBz is submicron to nanometer rod-like conducting particles with uniform sizes. Removing the templates did not affect the morphology but slightly reduced the size of the PBz particles. The size and morphology of PBz particles can be tuned by adjusting the amount of monomer. The PBz submicrorods showed 412 F·g^?1 specific capacitance in 0.3 mol·L^?1HClO₄ at the current density of 1 A·g^?1, indicating its better electrochemical activity. The specific capacitance of the PBz particles reduced less than 10% after 500 charge-discharge cycles at the current density of 3 A·g^?1, indicating its good cycling stability.     

Thermotropic liquid-crystalline behaviour from mixtures of non-mesogenic molecules

Abstract

A class of non-mesogenic molecules, which as mixtures exhibit monotropic nematic phases, is described.     

Thermotropic Liquid Crystalline Poly(Azomethine‐Ether)s Containing Dibenzylidene Derivatives in the Main Chain

A new homologous series of thermotropic liquid crystalline poly (azomethine‐ether)s based on dibenzylidene derivatives were synthesized by solution polycondensation of various diformyl‐α,ω-diphenoxyalkanes, I–VIII with 2,6‐bis(m‐aminobenzylidene)‐4‐phenylcyclohexanone X, and characterized by ¹H‐NMR, IR and elemental analyses. The inherent viscosities of the polymers were in the range 0.29–0.58 dI/g. All the poly (azomethine‐ether)s were insoluble in common organic solvents but dissolved completely in concentrated H₂SO₄ and methanesulphonic acid. The mesomorphic properties were studied as a function of the diphenoxyalkane space length. Analysis by DSC and optical polarized microscopy demonstrated that the poly (azomethine‐ether)s from nematic mesophases over wide temperature ranges.     

Initiation and inhibition of dealloying of single crystalline Cu3Au (111) surfaces

Dealloying is widely utilized but is a dangerous corrosion process as well. Here we report an atomistic picture of the initial stages of electrochemical dealloying of the model system Cu(3)Au (111). We illuminate the structural and chemical changes during the early stages of dissolution up to the critical potential, using a unique combination of advanced surface-analytical tools. Scanning tunneling microscopy images indicate an interlayer exchange of topmost surface atoms during initial dealloying, while scanning Auger-electron microscopy data clearly reveal that the surface is fully covered by a continuous Au-rich layer at an early stage. Initiating below this first layer a transformation from stacking-reversed toward substrate-oriented Au surface structures is observed close to the critical potential. We further use the observed structural transitions as a reference process to evaluate the mechanistic changes induced by a thiol-based model-inhibition layer applied to suppress surface diffusion. The initial ultrathin Au layer is stabilized with the intermediate island morphology completely suppressed, along an anodic shift of the breakdown potential. Thiol-modification induces a peculiar surface microstructure in the form of microcracks exhibiting a nanoporous core. On the basis of the presented atomic-scale observations, an interlayer exchange mechanism next to pure surface diffusion becomes obvious which may be controlling the layer thickness and its later change in orientation.     

Local and blowing‐up solutions for a space‐time fractional evolution system with nonlinearities of exponential growth

Local and blowing‐up solutions for the Cauchy problem for a system of space and time fractional evolution equations with time‐nonlocal nonlinearities of exponential growth are considered. The existence and uniqueness of the local mild solution is assured by the Banach fixed point principle. Then, we establish a blow‐up result by Pokhozhaev capacity method. Finally, under some suitable conditions, an estimate of the life span of blowing‐up solutions is established.