Coating Effects on Transient Cooling a Hot Spherical Body

A numerical solution is carried out to treat the transient cooling problem with conduction and radiation for a hot spherical body covered with a cold coating material. The solution includes the equations of radiative transfer, coupled with a transient energy equation that contains both radiative and conductive terms. The radiative transfer equation was solved by the discrete ordinates method, and a parmetric study was performed by changing various physical parameters such as the optical thicknesses, thermal conductivity of the coating, emissivity, and diffusivity of the sphere. It was found that the properties of the coating have a direct effect on the cooling rate of the sphere.     

球形Li1+xV3O8的制备及其电化学性能

Li1 xV3O8是一种很好的锂离子蓄电池正极材料。采用高温骤冷法制得V2O5溶胶,与LiOH溶液混合,通过喷雾干燥法制备中间产物,在350℃温度下热处理4h合成锂离子蓄电池正极材料Li1 xV3O8粉末。X射线衍射分析表明合成的Li1 xV3O8粉末结晶度较低。扫描电镜分析表明颗粒呈球形,粒径约为3μm;电化学性能测试结果表明,其首次充电比容量为333.4mAh/g,放电比容量为339.6mAh/g,具有优良的电化学性能。     

Spherical harmonic coefficients for the potential of a constant-density polyhedron

Recurrent relationships for the definitions of fully normalized spherical harmonic coefficients C?_n,m and S?_n,m are derived and integrated analytically to yield the gravitational potential of a constant-density polyhedron. The algorithm is expressed in a C language computer program.     

高密度高活性球形Ni(OH)_2的制备研究

采用“受控中和水解法”进行了金属氢化物－镍电池用的高密度高比容量球形Ｎｉ（ＯＨ）２的制备研究，讨论了ｐＨ值、添加剂、加氨量等操作条件对Ｎｉ（ＯＨ）２堆积密度及电活性等性能的影响。实验结果表明：用本文论述的方法可以制得高密度高比容量球形Ｎｉ（ＯＨ）２颗粒，振实密度在２．０ｇ／ｃｍ３以上，比表面积在１５～２０ｍ２／ｇ。添加氨水后可以改变Ｎｉ（ＯＨ）２的结晶程度，采用复合添加剂比单一添加剂更能有效地提高Ｎｉ（ＯＨ）２的活性和改善镍电极的性能。使用该Ｎｉ（ＯＨ）２作为活性物质的电极，其容量可达到２６０ｍＡｈ／ｇ。这种Ｎｉ（ＯＨ）２特别适合于用作金属氢化物－镍电池的正极活性材料。     

Fast computation of the spherical harmonic perturbation on an artificial satellite

Up till now, among the numerical computation methods of the spherical harmonic perturbation on an artificial satellite, the computation speed of Cunningham's method is the fastest However, running programs based on this method easily causes overflow. A method is presented, which has a computation speed higher than that of any other methods, and can avoid overflow in operation, even when the order and degree of the Earth's spherical harmonic perturbation are extended to 100 × 100 or more. It satisfies the requirements of the high-accuracy SLR, GPS, LLR, etc. This method has been programmed and used in practice Now a large-scale calculation related to the satellite precision ephemeris could be done just with a microcomputer.     

变径球面族包络曲面的应用研究

利用变径球面族包络曲面参数式方程研究水利水电工程中的弯管、圆柱岔管过渡带曲面等数学模型，并进行了计算机辅助几何设计．     

碳钢在亚硫酸铵制浆蒸煮过程中的电化学特性

用电化学方法研究了碳钢在亚硫酸铵法制浆蒸煮过程中的腐蚀行为．结果发现，在蒸煮前期温度较低时，碳钢表面呈活化状态；在蒸煮后期温度较高时，碳钢表面呈自钝化状态．电化学研究结果表明，对亚铵法蒸球不能应用外加电流阳极保护法．失重试验证实了电化学研究结果     

造纸蒸球的腐蚀与防护

研究了造纸蒸球的腐蚀机理，即蒸球的腐蚀主要是磨擦腐蚀、缝隙腐蚀及ＳＯ３２－等阴离子造成的均匀腐蚀，并提出了防止造纸蒸球腐蚀爆炸的措施．     

根据钻孔资料确定地下岩层产状——通用地质坐标系应用实例(之四)

根据钻孔资料确定地下岩层产状是一个比较复杂的问题。利用赤平极射投影网上的小圆相交方法,可以求得倾斜钻孔资料地下岩层的可能产状,但赤平极射投影网上的小圆作图比较复杂。利用通用地质坐标系可直接在球面投影上计算出两个小圆的交点,能更快更准确地得到结果。     

球面图及其在机械工程中应用的研究

本文针对机械工程中出现的复杂度较高的空间角度计算问题，提出了一种解决的新途径即球面图法，并着重分析了它的应用。