降低金刚石钻头烧结温度的方法

人相图上分析了制取预合金胎体粉末以降低钻头烧结温度的可行性，并结合生产实践介绍了２种预合金粉末的制备方法，从而把制造金刚石钻头的烧结温度降低到９００℃。     

A QUASI-TWO-DIMENSIONAL STREAM TUBE MODEL FOR SIMULATING FLOW IN ALLUVIAL RIVERS

I. INTRODUCTIONIt is necessary, sometimes, to predict river bed deformahon during the alanning and design stages of a hydraulic project. As the nuvial process is quite complicated, the I --Dmathematical models currently in use can not satisfy the various needs in hydraulic engineering. Particularly in engineering practice, there is a strong desire of knowing the hydraulicconditions and river bed deformation in details. Some two dimensional models as well asqusi--two--dissensional models …     

ASSESSMENT OF THE EFFECTIVE RANK OF A (CO)VARIANCE MATRIX: A NON-PARAMETRIC GOODNESS-OF-FIT TEST

Each eigenvector of the dispersion matrix[X]~T[X]was shown to be a partial predictor of the originaldata matrix [X],the sum of the predictions from the individual principal components being equal to theexpectance of [X].By comparing the distributions of the members of two neighbouring predictedmatrices,[X]_(1...i)and [X](1...i+1)(i.e.the sums of the first i and i+1 individual predictions respectively),it was shown that they should be indistinguishable provided that i is equal to or greater than the effectiverank of [X],and significantly different otherwise.This was confirmed by analysing the visible absorptionspectra of methyl orange and methyl red solutions as well as the Raman spectra of Na_2SO_4 and MgSO_4solutions.On the grounds of these findings,a non-parametric goodness-of-fit test for assessing theeffective rank of[X]was proposed which proved to be comparatively conservative and more robust thanmost currently used tests.     

新疆齐求Ⅰ金矿床毒砂及其在金的成矿过程中的作用

所研究的毒砂形成两个成矿阶段。成矿前阶段的毒砂具有颗粒粒大、裂隙发育和明显的成分环带等特征。成矿前的裂隙为金的迁移和沉淀提供了良好的空间。成矿期阶段的毒砂颗粒细小,无成分环带。根据形态、分布规律和成分特点,成矿期毒砂可划分为两个世代:早期的,自形程度高,无明显成分异常;晚期的,他形晶,含砷低。毒砂的特性反映了金的成矿作用的演变过程。