“双转移”背景下的河源产业集群内企业竞争力研究

河源若想抓住＂双转移＂这个契机加速发展,就势必要结合河源的产业发展现状及资源状况,选择有优势的产业重点培育,发展壮大一些龙头企业,进而带动中小企业的发展,提高区域竞争力。区域竞争力的不断增强,也势必会促进更多、更优秀的企业来河源发展。同时,集群内企业也要充分利用这一机遇,利用企业内外资源,加快提升自身的竞争力。     

考虑互动特性的水火电力系统优化调度策略

针对水火电联合运行的电力系统,首次利用优化的方法分析水电和火电间的相互作用规律和负荷的空间分布特性对电力系统节能运行的影响规律,揭示了其联合运行时的水电和火电的运行特征.以此为基础,构建了可充分发挥梯级水电站互动特性的优化调度模型.以一个含有梯级水电站的水火电力系统为例进行分析,结果表明可通过充分发挥水电能源的互补作用,实现非可再生能源的节约和促进能源的可持续高效利用.     

Microwave permeability of single cobalt nanotube studied by micromagnetics simulations and generalized Snoek’s law

Microwave permeability spectra of single Co nanotube under equilibrium state have been studied by micromagnetics simulation.More than four obvious resonance peaks have been found(11.72,24.20,33.18 and 39.55 GHz).Such large resonance frequency cannot be found in other traditional magnetic materials.The configurations of magnetic moments along the nanotube have been simulated.The results show that the top end of nanotube has a"flow-out"pattern of magnetic moments configuration.The bottom end has a"flow-in"pattern of magnetic moments configuration.The magnetic moments within the main body of nanotube are aligned perfectly along the length of nanotube.The magnitude of natural resonance peak is strongly related to the volume fraction of a zone,which has the same orientation of magnetic moments.Large microwave permeability values have been found for single nanotube.The generalized Snoek’s law has been used to validate the micromagnetics simulations in this paper.     

Heterogeneous acid catalytic esterification by porous polyoxometalate-tantalum pentoxide nanocomposites

Polyoxometalates (POMs) are useful catalysts in both redox and acid catalysis reactions since its catalytic features can be controlled at a molecular level. We investigated POM (POM = H₃PW₁₂O₄₀) on tantalum pentoxide (Ta₂O₅) via hydrolysis of tantalum pentachloride (TaCl₅) in the presence of POM using the sol-gel method for acid catalytic reaction. All obtained amorphous materials have been characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier transform infrared (FT-IR) spectra, Raman scattering spectroscopy, ³¹P magic-angle spinning (MAS) NMR, field emission scanning electron microscopy (FESEM), and nitrogen adsorption/desorption analysis, in order to confirm the structure integrity of the Keggin unit in as-prepared composites and investigate the morphology and surface textural property of the composites. Catalytic activity of the catalysts has been evaluated for esterification of acetic acid with ethanol as a model reaction with different catalytic reaction parameters such as POM loading, reaction time, catalyst dose, molar ratio of the reactants, etc. The conversion of ethanol reached 87.4 % and the turnover frequency (TOF) was 2.9×10³.Meanwhile, it is easy to separate and recover POM/Ta₂O₅ from the reaction system.     

基于计算机视觉的腾空飞脚错误动作识别模型

以南拳项目中腾空飞脚动作为例,依据2003版竞技武术套路竞赛规则,建立三维坐标系,将动作质量(A组)评分规则中的腾空飞脚动作的扣分规则进行形式化描述,以利于电子裁判对错误动作进行识别.针对每个动作建立错误函数和基于计算机视觉的腾空飞脚动作扣分模型,并举例说明.     

塑料瓶贴标用乳液胶的研究

本文分析了塑料瓶的表面结构特性及其对贴标胶的要求，简介乳液胶的合成过程，讨论了聚会温度、搅拌速度、增粘剂和改性剂对贴标胶的影响。     

活性石灰在冶金生产中的应用

介绍了活性石灰在炼钢、铁水预处理、精炼、烧结等冶金生产中的应用。     

The influence of publication delays on three ISI indicators

Summary Based on the transform function model of the observed citing process, the analytical expression of the age distribution of citations is deduced, and it is theoretically proved that the peak value of the citation distribution curve would fall and shift backward along with increasing the average publication delay and the peak age has a direct proportion relation with the pure delay and would be prolonged along with increasing the delay or decreasing the aging rate. The influence of the average publication delay on three ISI indicators impact factor, immediacy index and cited half-life are studied; in one subject discipline, the bigger the delay, the lower the three indicators of journals. Using the sensitivity theory, sensitivity formulae of the three indicators to publication delay parameters are deduced and it is found that responses of these indicators to changes of publication delays are different according to different time constant of the aging process; The faster the aging rate of a discipline literature is, the worse the influence of publication delays on the indicators of journals in the discipline.     

Piezoelectromagnetic waves guided by the surface of a ceramic cylinder

Summary The propagation of shear horizontal (SH) waves over the surface of a circular cylinder of polarized ceramics is studied from the three-dimensional equations of linear piezoelectromagnetism with full electromagnetic coupling. An exact solution is obtained.