Theoretical Maxwelrs Equations, Gauge Field and Their Universality Based on One Conservation Law

The notion of the inner product of vectors is extended to tensors of different orders, which may replace the vector product usually. The essences of the differential and the codiffcrential forms are pointed out： they represent the tangent surface and the normal surface fluxes of a tensor, reslpetivcly. The definitions of the divergence and the curl of a 2D surface flux of a tensor arc obtained. Maxwell＇s equations, namely, the constraction law of field, which were usually established based on two conservation laws of electric charge and imaginary magnetic charge, are derived by the author only by using one conservation law （ mass or fluid flux quantity and so on） and the feature of central field （or its composition）. By the feature of central field （or its composition）, the curl of 2D flux is zero. Both universality of gauge field and the difficulty of magnetic monopole theory （ a magnetic monopole has no effect on electric current just like a couple hasing no effect on the sum of forces） axe presented： magnetic monopole has no the feature of magnet. Finally it is pointed out that the base of relation of mass and energy is already involved in Maxwell＇s equations.     

星月公司无石棉无金属摩擦材料面世

绿色、环保型无石棉无金属摩擦材料，近日在河北星月制动元件有限公司问世。该公司经过长期探索、试验与筛选．利用陶瓷纤维良好的耐热性能和耐化学性能研制的这种新材料，有效地克服了石棉对人体的危害和对环境的污染，消除了金属材料过高的热传导性和易生锈的弊端．具有良好的社会效益和广阔的发展前景。     

用WKB法的近似解作为精确解求微分方程

用ＷＫＢ近似方法解薛定谔方程，得到的解是近似的，本文提出一种用该近似解作为精确解求微分方程的方法，求得该微分方各国分析解的近似条件及解的近似程度等问题。     

基于非量测数字相机的近景摄影测量

介绍了应用基于非量测数字相机的近景摄影测量方法进行建筑物外形的测量，通过直接线性变换（DLT）计算未知点的空间三维坐标，并探讨了数字影像畸变改正对解算结果的影响，应用此方法很好地解决了人体骨架模型的测量。     

关于Liénard方程的极限环

本文讨论 Liénard 方程极限环的存在性,证明了 Liénard 方程至少存在一个、n个极限环的充分性定理,推广了文[4]～[6]的某些结果。这些定理给出的条件均可估计极限环的存在区域。