几种棉田除草剂大田防除效果及其对棉花的安全性测定

田间药效结果表明，氟乐灵、甲草胺、乙草胺、异丙甲草胺、二甲戊乐灵、扑草净、曙草灵、仲丁灵8种土壤处理剂无论是对禾本科杂草还是对阔叶杂草都有较好的防效，而且比茎叶处理剂的持效期长；烯禾啶、精吡氟禾草灵、精喹禾灵、高效氟吡甲禾灵4种茎叶处理剂对禾本科杂草的防效较好，而对阔叶杂草无效。室内安全性测定表明，甲草胺、乙草胺和异丙甲草胺对棉花的安全性较差，二甲戊乐灵对棉花的株高有一定的抑制作用，但对鲜重没有抑制作用，其他药剂没有明显的影响。     

基于CMFS-MIC特征选择的跳频电台个体识别方法

针对跳频电台细微特征集中存在冗余特征等导致电台识别时存在计算量大、识别准确率低等问题,提出了一种基于CMFS-MIC特征选择的跳频电台个体识别方法。首先计算采集到的各个跳频电台信号样本的细微特征集,然后采用关联信息熵度量特征子集的组合效应,兼顾考虑特征间的关联关系和冗余关系对各个特征进行降序排序。在此基础上,采用最大信息系数度量的近似马尔可夫毯方法删除冗余特征,实现对特征子集进行优化和降维。最后,设计了投票组合分类器实现对4部跳频电台信号的识别。仿真结果表明,本文算法具有更高的分选识别率。     

含C_4A_3早强矿物的硅酸盐水泥熟料体系的研究

研究了在硅酸盐水泥熟料中引入C4A3的条件、生料的易烧性、适宜的煅烧温度及水泥的性能。研究结果表明,合理的矿物组成、掺入适量的石膏和助熔剂是实现C3S-C4A3共存的前提条件。通过在C3S-C4A3S-C2S-C4AF熟料体系中引入5%～20%的C4A3S,所制备的熟料体系具有良好的强度性能,其3d强度在15～30MPa,7d强度在25～40MPa,28d强度在45～65MPa之间。     

Microstructures and mechanical properties of polypropylene/polyamide 6/polyethelene-octene elastomer blends

A series of polymer blends were designed and manufactured. They are composed of three phases: polypropylene (PP), polyamide-6 (PA6) and polyethylene-octene elastomer (POE) grafted with maleic anhydride. The weight fraction of PA6 was adjusted from 0 to 40% by increments of 10%, and the weight fraction of POE was systematically half that of PA6. The morphology, essentially made of PA6 particles dispersed in the PP matrix, was characterised by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the extruded plates prepared with the blends, the shape of the dispersed PA6 particles showed an elongated ellipsoidal shape, whose aspect ratio increased somehow with alloying content. The POE modifier was observed both as a thin interlayer (less than 100 nm thickness) at the PP/PA6 interface, and as a few isolated particles. The elastic modulus and yield stress in tension are nearly constant for PP and blends. By contrast, the notched Izod impact strength increases very much with alloying content. This remarkable effect is interpreted in terms of POE interphase cavitation, enhanced plastic shear deformation and resistance of PA6 particles to crack propagation.     

天然原料碳热还原氮化合成β′-SiAlON的研究进展

本文介绍β′-SiAlON的结构、基本性能及应用领域,阐述了合成β′-SiAlON的原材料和各种合成方法,重点介绍了利用天然原料合成β′-SiAlON的还原剂外加法和还原剂内加法即有机插层法。详细阐述了各工艺条件(反应原料的组成、反应温度、反应时间、反应气氛、流速及反应物颗粒尺寸、添加剂等)对合成β′-SiAlON反应结果的影响。同时本文指出目前该研究可能存在的问题及解决的途径。     

公式分层的谓词模态逻辑

由于必然模态词□的引入,谓词模态逻辑的公式在一个可能世界中的真假值可能依赖于其可达的可能世界.在谓词模态逻辑中存在个体跨可能世界相等问题.针对这一问题,Lewis提出了对应物理论,并且在对应物理论中用对应物关系来表示个体跨可能世界相等.但是,当一个对象具有一个以上的对应物时,谓词模态逻辑中的跨可能世界相等关系无法与对应物关系建立一一对应.通过限制谓词模态逻辑中全称量词∀的范围,给出了一种公式分层的谓词模态逻辑.它是谓词模态逻辑的一个子逻辑,并且其语言与谓词模态逻辑的语言是相同的.但其公式是分层定义的,使得∀可以出现在□的范围内,并且□不能出现在∀的范围内.由于任意形如∀x□φ（x）的表达式都不是该逻辑的公式,以量词开头的公式在一个可能世界w中的真假值只依赖于w,该逻辑避免了个体跨可能世界相等问题.给出了该逻辑的语言、语法和语义,并证明了该逻辑是可靠的和完备的.     

β-sialon结合SiC复相材料的分相抗氧化行为

对粘土类原料碳热还原及氮化反应法合成的β-sialon结合SiC复相耐火陶瓷材料进行了不同氧化条件下的抗氧化性实验。研究表明：1300℃时的氧化过程在12h内为化学反应控制阶段，12h后为扩散控制阶段。扩散控制阶段反应符合Ginsterlinger扩散动力学关系。首次分别得到复合状态下的β-sialon基质相、SiC颗粒相及β-sialon结合SiC复合相在1300℃下的分相扩散控制型抗氧化反应动力学方程，从各相的扩散控制型反应级数确认了β-sialon基质相对SiC颗粒相的高温氧化保护作用以及复相材料具有的优异抗高温氧化性能。     

Polypropylene/polyamide 6/polyethylene-octene elastomer blends. Part 3. Mechanisms of volume dilatation during plastic deformation under uniaxial tension

It has been shown in a previous paper in this series that important dilatation is produced by plastic deformation under tension of neat PP and PP/PA6/POE blends, for which the POE to PA6 concentration ratio equals 1/2. In this work, the detailed mechanisms of this volume change are investigated from electron micrographs (SEM and TEM) obtained in the deformed state. At low alloy content, it is thus observed that dilatation results from decohesion of the PA6 particles from the PP matrix. As the amount of PA6 and POE increases, voids are nucleated preferentially in the thicker POE interphase making a shell around the PA6 particles, and secondarily in isolated POE particles. Unexpectedly, it has been found that the overall volume dilatation decreases with total alloying content. This is interpreted by: (i) the increasing contribution of PA6 that intrinsically deforms with less cavitation than PP, (ii) the post-cavitation rubber-like stretching of POE particles and, (iii) the early formation of a percolating network of shear bands from the diffuse array of voids formed after the yield point. These mechanisms explain the gradual increase of the resistance to impact of the PP/PA6/POE as their alloying content is increased.     

正交车铣复合加工的切削用量优化

针对正交车铣复合加工的生产效率和生产成本多目标的切削用量优化问题,确定了切削速度、轴向进给量、工件转速为优化设计变量。建立了正交车铣复合加工的优化目标函数。从机床、工件、刀具的特性等方面考虑,建立了约束条件方程。采用统一目标法求解了正交车铣复合加工的切削用量优化.     

Si基薄膜太阳电池绒面ZGO透明导电膜的研究

采用孪生对靶直流磁控溅射的方法在室温下制备高质量的Ga掺杂ZnO(ZGO)透明导电薄膜,用HCl腐蚀的方法获得满足光散射特性的绒面ZGO薄膜。制备的ZGO样品为具有六角纤锌矿结构的多晶膜,具有(002)方向的择优取向。腐蚀后,绒面ZGO薄膜的晶粒度减小,电阻率基本不变。在可见光范围内,绒面ZGO的反射率比平面ZGO的反射率下降了10%左右。将绒面ZGO薄膜应用于p-i-n型非晶Si薄膜太阳电池中,有效提高了太阳电池性能,使得电池的短路电流提高到17.79 mA/cm2,电池的转换效率增加到7.23%。