区组大小为3的四重单纯支架

一个(K,λ)支架是一个区组集可分为若干个带洞平行类的可分组设计(K,λ)-GDD(X,G,B),每一个带洞平行类为XGj的一个划分,其中Gj∈G.若一个(K,λ)支架的区组集中任意两个区组是不相同的,则称它是单纯的.单纯的支架对构造单纯的可分解填充设计有很重要的作用,后者可以用来构造统计学中的均匀设计.本文通过直接构造和递推构造的方法证明了组型一致的(3,4)单纯支架存在的必要条件也是充分的.     

Synthesis process of Ba-ferrites from α-FeOOH and γ-FeOOH and investigation of magnetic properties

The claviform BaFe₁₂O₁₉ crystals were synthesized by the precipitation-toptactic reaction method using α-FeOOH and γ-FeOOH as raw materials respectively. The synthesis processes of BaFe₁₂O₁₉, studied by XRD, SEM, EDS, FT-IR, and TG-DTA techniques, included preparations of precursor γ and precursor α, formations of α-Fe₂O₃ and BaFe₂O₄, and production of rod-like BaFe₁₂O₁₉ through dehydroxylation of pod-like FeOOH, followed by reactions of α-Fe₂O₃ with BaCO₃ and BaFe₂O₄. The crystallinity of α-Fe₂O₃ and BaCO₃ from precursor α was better than from precursor γ due to the direct dehydroxylation of α-FeOOH, resulting in a lower nucleation rate and better crystallinity of BaFe₂O₄. BaFe₁₂O₁₉ prepared from precursor α showed lower crystallinity and purity with a higher length-diameter ratio than from precursor γ. The VSM results proved that the appearance of final products had an important influence on magnetic properties.     

Solidification microstructure and phase constitution of Fe-7.5%Mo-16.5%Si ternary quasiperitectic alloy

Solidification of Fe-7.5%Mo-16.5%Si ternary quasiperitectic alloy is investigated by using differential scanning calorimetry (DSC) and drop tube containerless processing techniques.The primary phase is identified as R (Fe5Mo3Si2) and the quasiperitectic phases are τ1 (Fe5MoSi4) and Fe3Si.With the decrease of droplet diameter, the cooling rate and undercooling of the droplets in-crease rapidly.The experiment result indicates that the solidification microstructure is composed of remnant primary phase, qua-sip...     

铁路基床翻浆冒泥病害成因的细观机理分析

基于朔黄铁路基床填料动力响应特性试验数据,建立PFC2D饱和粗颗粒土动三轴数值模型,选用线性黏结颗粒接触反映粗颗粒土的黏结特性,从细观力学和几何学角度研究翻浆冒泥病害形成的细观机理。结果表明:该数值模型能较好地反映粗颗粒土的动力响应特性。振动荷载通过改变土体颗粒与颗粒之间的接触荷载,破坏颗粒间的黏结键,形成自由颗粒和孔隙,造成基床软化,并最终形成翻浆冒泥病害。围压和土体颗粒间黏结作用越小,试样越容易发生软化,形成翻浆冒泥病害,基床强化应从改善基床表层和道床的围压状态以及提高颗粒间的黏结强度两方面采取措施。     

浙江沿海虾蛄生物学及其开发利用研究报告

本文根据浙江省教委、省基金、舟山市科委关于浙江沿海虾蛄生物学及其开发利用研究的要求，对四年多来的研究进行总结，主要包括资源与分布、生物学习性、暂养及运输技术、营养成份分析、开发利用等诸方面     

Guaranteed Cost Finite-Time Control of Fractional-Order Nonlinear Positive Switched Systems with D-Perturbations via MDADT

This paper is concerned with the problem of guaranteed cost finite-time control of fractionalorder nonlinear positive switched systems(FONPSS) with D-perturbation. Firstly, the proof of the positivity of FONPSS with D-perturbation is given, the definition of guaranteed cost finite-time stability is firstly given in such systems. Then, by constructing linear copositive Lyapunov functions and using the mode-dependent average dwell time(MDADT) approach, a static output feedback controller is constructed, and sufficient conditions are derived to guarantee that the corresponding closed-loop system is guaranteed cost finite-time stable(GCFTS). Such conditions can be easily solved by linear programming. Finally, an example is provided to illustrate the effectiveness of the proposed method.     

科技型中小企业技术创新的资金支持——基于生命周期视角的研究

基于生命周期的视角分析了科技型中小企业发展过程中各个阶段的特点,以及各个阶段中技术创新与资金支持的矛盾.在新的经济环境与政策条件下,构建了解决这种矛盾的资金支持体系,探讨了企业发展和技术创新过程中具体的融资方式,并且提出了相关的政策建议.     

从三峡工程建设谈我国当前 的企业创新工作

企业创新是建立创新型国家的根本要求。三峡工程建设者通过集成创新、引进消化吸收再创新和 原始创新,实现了在大坝混凝土快速施工技术、７０万kW水轮机水力设计安装制造、双线五级船闸高边坡稳定 支护等１００多项关键技术的重大突破。但当前我国的大多数企业存在着技术引进消化吸收率低、自主知识产 权少、研发投入不足等严重制约创新的突出问题。为实现到２０２０年建设创新型国家的目标,我国企业需要在 挖掘自主创新能力、加强创新队伍建设等六个方面去培育和提高企业的创新能力。     

Preliminary regional estimation of carbon sink flux by carbonate rock corrosion: A case study of the Pearl River Basin

The formation of carbonate rocks has had a dramatic sink effect on atmospheric CO2 throughout geological time.The wide global distribution of carbonate rocks and their strong sensitivity to climate change mean that carbonate rock corrosion consuming air/soil CO2 can play an important role in the global carbon cycle.The carbon sink accounts for 12.00%-35.29% of the missing carbon in the global carbon cycle.Using the Pearl River Basin as a case study,we analyzed comprehensively the factors impacting karstific...     

Angular dependent NEXAFS study of the molecular orientation of PTCDA multilayers on Au （111） surface

The molecular orientation of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) multilayers adsorbed on Au (111) surface has been investigated using angular dependent O K-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The significant angular dependence of important resonant structures (π* and σ*) reveals that PTCDA molecules adopt an ordered geometry on the substrate surface. The average tilt angle of the PTCDA molecular planes is 27°±10° from the Au (111) surface.