静电纺丝技术制备二氧化铈纳米纤维

采用静电纺丝技术制备了PVP／Ce（NO3）3复合微米纤维,研究了反应体系的最佳组成,获得了最佳制备条件。将PVP／Ce（NO3）3复合微米纤维在600℃焙烧10h,获得了晶态CeO2纳米纤维。XRD分析表明,PVP／Ce（NO3）3复合纤维为无定型,CeO2纳米纤维为立方晶系,空间群为OH^5-F^M3m。SEM分析表明,PVP／Ce（NO3）3复合微米纤维表面光滑,平均直径约为1．0～2．0μm;所制备的CeO2纳米纤维的平均直径为300nm,长度大于50μm。     

脱色剂对月见草油品质的影响

采用不同脱色剂在真空条件下对月见草油进行脱色,分别以茴香胺值、酸值、色价为考察指标,所得脱色油品质的各指标与脱色前进行比较,综合研究表明,脱色剂白土+活性炭脱色效果最好.     

一阶常微分方程具有乘积形式f(x~αy~β)g(ax~t+by~s)积分因子的求解

讨论了一阶常微分方程M（x,y）dx＋N（x,y）dy=0的积分因子问题,给出了方程具有形如f（x^αy^β）g（ax^t＋by^s）,a,b,α,β,t,s∈R的积分因子的充要条件,引入了一种新的求上述积分因子的方法,并通过实例加以应用。     

Analysis of contact melting around a horizontal elliptical cylinder heat source

The process of △T-driven contact melting of the solid phase change material (PCM) around an horizontal elliptical cylinder heat source is analyzed. Aiming at the problem existed in the published literature, namely the thickness of boundary layer tends to be infinite at = 90o, and considering the difference of normal angle between the horizontal elliptical cylinder surface and the solid-liquid interface of PCM, a new mathematic model is proposed, and the fundamental equations for the melting process are derived with the film theory. The new pressure distribution inside the boundary layer, the variation law of normal angle of the solid-liquid interface, the thickness of the boundary layer and the relationship between the melting velocity and resultant force are obtained. The solutions of the fundamental equations under different elliptical compression coefficients are analyzed and discussed. It is found that the thickness of the boundary layer obtained by the new model is a finite value and accords with the experimental result at = 90o.     

比较优势、竞争优势与河南省区域发展战略

以比较优势、竞争优势理论为支撑,通过对中部6省要素禀赋和制造业比较优势及竞争优势的比较分析,发现河南省具有劳动力资源最为丰富、土地次之、资本最为稀缺等特点,河南省制造业的竞争优势虽以比较优势为基础,但近年来一些行业过快的资本增密速度与要素禀赋形成了明显的错位.最后指出河南省区域发展战略必须实现比较优势与竞争优势的有机互补和结合,并提出了将比较优势转化为竞争优势的途径与对策.     

一个制造型企业的资源影子价格分析

文章研究的主要目标是对山西某公司生产资源的影子价格进行评估和分析,资源主要包括煤、水力和电。所用的评估方法为线性规划,所使用的软件为Excel和Win QSB。这个评估是对该公司生产资源影子价格的首次评估,其评估结果和评估模型都具有实际应用和推广价值。     

浅谈高校图书馆网站系统功能的开发

针对高校图书馆读者对网站功能的需求,总结和探讨了开发高校图书馆网站系统常用功能的有关问题。     

太原城区城市公园绿地的分布、功能与发展定位

通过对太原尖草坪区、杏花岭区、迎泽区、晋源区、万柏林区、小店区的城六区公园绿地2003-2013年统计数据和130家公园百度搜索资料分析看出,太原城区公园绿地呈自西、北向东南递减趋势,中心城区、城区边缘、城区外围由内向外形成历史文化、重工业基地和红色文化与自然生态景观三个公园景观圈的空间分布特征,同时发现太原人均公园绿地仍低于全国平均水平,城区东南部公园绿地严重缺乏,绿化功能突出游憩功能不足等分布和功能定位问题,在此基础上提出整体优化空间布局、功能主题化定位和投融资模式改革发展建议.     

A Second-Order Sliding Mode Controller of Quad-Rotor UAV Based on PID Sliding Mode Surface with Unbalanced Load

Quad-rotor unmanned aerial vehicle(UAV) is a typical multiple-input-multiple-output underactuated system with couplings and nonlinearity. Usually, the flying environment is very complex,so that it is impossible for the UAV to avoid effects derived from disturbances and uncertainties. In order to improve the reliability of flight control, we established the dynamic model of quad-rotor UAV by Newton-Euler equation in unbalanced load conditions. Considering external disturbances in the attitude, a second-order sliding mode controller was designed with PID sliding mode surface and Extended State Observer(ESO). The simulation experiments have got good control performance,illustrating the effectiveness of our controller. Meanwhile, the controller was implemented in a quadrotor UAV, which carried a pan-tilt camera for aerial photography. The actual flight experiments proved that this paper dealt with the high stabilization flight control problem for the quad-rotor UAV,which laid a good foundation for autonomous flight of the UAV.     

三角矩阵环上的Gorenstein AC-投射模

考虑三角矩阵环上的Gorenstein AC-投射模. 设T是三角矩阵环, 其中A和B是环, U是(B,A)-双模. 证明: 若_BU是平坦模, U_A是有限生成投射模, 则左T-模M是Gorenstein AC-投射模当且仅当M₁是Gorenstein AC-投射左A-模, φ^M是单同态, 且Coker φ^M是Gorenstein AC-投射左B-模.