喷嘴内液固两相射流流场的数值模拟

基于连续介质理论,考虑了液固两相间的相互作用,给出了喷嘴流道内液固两相射流的控制方程,利用标准的k-ε两方程模型对磨料射流喷嘴内流场进行了数值模拟研究,并对模型中的主要参数进行了优选。研究结果表明,水与磨料颗粒之间存在速度滑移,在相间力的作用下磨料颗粒一直作加速运动,颗粒速度逐渐趋向水的速度;进入喷嘴收缩段后,水与磨料颗粒同时得到加速,但由于惯性力的作用,达到相同速度磨料颗粒的加速过程要长;进入直柱段后,液相速度继续增加至最大速度,此后缓慢降低,而磨料颗粒在整个直柱段内一直加速,液固两相的速度差逐渐减小,直至从喷嘴喷出;喷嘴出口处液固两相的速度剖面近似为抛物线形,在喷嘴截面中心处速度最大,沿径向逐渐减小,离壁面越近,速度降低的幅度越明显。与前人的研究结果对比发现,模拟所得的结果是正确的。     

门限回归模型预测粤中西部冬春气温

用门限自回归模型和混合门限回归模型对广东省中西部的冬春季平均气温做预测。选取北半球500hPa高度场和太平洋海温场的分区分季节的多个气候背景场的前若干个主分量作为因子（共1792个），这些因子包含着气候背景场的主要信息，通过对预报量和预报因子群的相关筛选，选取相关系数最大的因子建立混合门限非线性回归模型。并初步探讨了气候背景场对预报量的影响。结果表明：混合门限回归模型优于门限自回归模型；前者能较好地拟合冬春气温序列，预报效果较理想。粤中西部冬季气温场与东北半球南部3—4月高度场第5个主模态相关最密切，当3—4月500hPa高度场东亚大陆为低槽控制，日本海太平洋附近为高压脊，有利于当年冬季气温偏低；春季气温场则与北半球冬季500hPa高度场第8个主模态相关密切，当冬季500hPa高度场乌拉尔山附近地区为明显的阻塞高压形势，有利于次年春季气温偏低。     

用场图分析导体在静电平衡时的表现

利用静电场的场图讨论、分析了导体在静电平衡时的一些问题，加深了对物理场的理解。     

Addition Sequence Method of Scalar Multiplication of Elliptic Curve over OEF

A new elliptic curve scalar multiplication algorithm is proposed. The algorithm uses the Frobenius map on optimal extension field (OEF) and addition sequence. We introduce a new algorithm on generating addition sequence efficiently and also give some analysis about it. Based on this algorithm, a new method of computing scalar multiplication of elliptic curve over an ()EF is presented. The new method is more efficient than the traditional scalar multiplication algorithms of elliptic curve over OEF. The comparisons of traditional method and the new method are also given.     

Field Emission Characterization of 1D-Nanostructural ZnO Grown at Low Temperature

Ondeu-ctdio rmse nhsaivoen aaltt rwaicdteed b aan gdr-egaatp d neaaln oosft uartctteunrtialon se bmeiccaounse-of their remarkable physical and chemical properties[1 ,2].Amongthose properties ,the highaspect ratio of these materi-als makes them genuine can…     

Synthesis of trans-bis（glycinato） copper（Ⅱ） complex nanorods by room temperature solid-state reaction

Trans-[Cu(glyo)2(H2O)] nanoparticles with average diameters about 20-30 nm were prepared by onestep room temperature solid-state reaction. Trans-[Cu(glyo)2]nanorods with diameters ranging from 100 to 150 nm and lengths up to several μm were also prepared by one-step room temperature solid-state reaction in the presence of a suitable nonionic surfactant PEG400. The chemical composition and structural features of the products were investigated by elemental analyses, XRD, TG, SEM and TEM, respectively. The mechanisms of formation were also discussed.     

利用温度梯度法合成硫化物

以金属镁、钛、锆和钨以及升华硫为原料，通过温度梯度法合成了硫化镁、硫化钛、硫化锆和硫化钨，并利用X射线衍射分析了合成物的矿物组成，研究了合成体系内升华硫的蒸发量与合成体系容积大小、合成温度以及合成体系抗压强度等参数间的关系．研究结果表明，在本实验条件下，合成体系内的最大升华硫蒸发量应为1．15g，并根据此硫蒸发量控制合成体系内的温度梯度和升温速度，安全且大量地合成了硫化镁、硫化钛、硫化锆和硫化钨，其质量分别为56．37，112．00，155．36和247．97g．     

The Application of Microwave Low Temperature Plasma in Pretreatment of Cotton Fabric

The effect of microwave low temperature plasma pretreatment on desizing and removing natural impurity of cellulose fiber was studied. The influencing factors of pretreatment such as treating power, gas pressures and time were discussed in detail and the final effect had been compared with that of traditional pretreating process of cotton fabric. The results showed that better capillary effect, strength, whiteness and dyeing K/S value could be given by means of microwave low temperature plasma treatment.     

高效立体种植技术

推广应用高效立体种植技术是农业增产、农民增收的有效途径。介绍了高效立体种植技术的种植模式和配套措施。     

晶体中稀土离子4f^ N组态内光子跃迁强度的计算

在介绍晶体场导致稀土离子“能级分裂”和4 f^N组态内单光子跃迁的宇称禁戒的“部分解除”的基础上,讨论了该组态内单光子、双光子跃迁及电子拉曼散射几率计算的国际动态,总结了我们在此领域的工作并提出了进一步工作设想.