45钢固体粉末法稀土、硼、铬、铝共渗工艺研究

研究了RE_Mg合金对固体粉末法硼、铬、铝共渗层成分、组织和性能的影响 .发现随着RE_Mg合金加入量的增加 ,渗层中Al2 O3的量不断增多 ,当RE_Mg合金加入量为 5 %时 ,渗层中出现连续致密分布的Al2 O3黑区组织 ,对此进行了性能测试和机理探讨     

APPLICATION OF BORON MODIFIED SILICA SOL ON RETENTION AND DRAINAGE

INTRODUCTIONRecently with the high speed, large-scale develop-ment of papermaking, in the manufacture of paper and paperboard conventional single and dual reten-tion and drainage systems cannot obtain satisfying re-tention and drainage. So in 1980 microparticulate systems appeared. Because of its superiority such as good retention effectiveness on fine and chemicals, improving drainage and paper formation, reducing waste water and enhancing the concentration of white water for good recover…     

脉冲等离子体气相合成氮化硼的研究

以Ｂ２Ｏ３粉扩ＮＨ３为原料，用脉冲等离子体反应器合成ＢＮ，所得产品经Ｘ射线衍射，红外光谱分析表明，产品中除含六方氮化硼外，还含有少量立方氮化硼，生产工艺简单。     

Carbon isotope anomaly in marbles associated with eclogites from the Dabie Mountains

This is a report of carbon isotope anomaly in marbles associated with the UHP eclogites from the Dabie Mountains. The results place constraints on the degree of crust-mantle interaction during the UHP metamorphism.     

Preliminary study on climatic signals of stable isotopes from Holocene speleothems under monsoon condition

Within the East Asian monsoon zone the change in oxygen isotope of Holocene stalagmite is mainly related to monsoon rain rather than to temperature. And carbon isotope can be taken as a comprehensive signal which contains the natural information and the information of anthropogenic activity. Isotopic analysis is also compared with the annual layer records.     

超声波法合成三烷基硼及其裂解制备碳化硼

在超声波作用下采用一步合成法分别制备三乙基硼、三丙基硼和三丁基硼;考察超声波作用对合成产物产率的影响,用红外光谱及元素分析表征合成产物的结构;以合成的三乙基硼、三丙基硼和三丁基硼为原料通过热裂解制备纯度较高的碳化硼超硬材料;讨论不同原料和裂解温度对合成产物中C含量的影响.研究结果表明:以三乙基硼为原料在温度为1 400K进行裂解时,其裂解产物中B4C,B2O3和裂解自由碳的含量分别为94.0%,2.2%和3.8%.     

A carbon- and oxygen-isotope record of recent environ- mental change from Qinghai Lake, NE Tibetan Plateau

An understanding of natural climatic variability is essential for evaluating anthropogenic impacts on recent and future climate[1—3]. Due to the lack of lengthy instrumental records, such an understanding must be gained from natural archives of climate change. Palaeolimnological indicators of past lake levels may provide a sensitive record of changes in effective precipitation in closed basins. This approach is particularly relevant on the Tibetan Plateau, where instrumental records are very…     

氮化硼先驱体的合成与研究

以三氯化硼，三乙胺为原料，在氮气保护气下，经低温反应合成了配位键化合物Et3NBCl3，再与（Me3Si2)NH反应，得到了中间产物（Me2Si)2NBC2和（Me2Si)2NB(Cl)NHSiMe3，进而通过热缩合成环和高分 子化后，获得了具有B、N六元环结构的BN先驱体，合成的BN先驱体，软化点为40－50℃左右，且热处理后软化点的温度可提高至60－70℃左右，可纺性能良好，获得的淡黄色，半透明且表面光滑的先驱体丝，在氮气中热分解至1500℃，获得了含有不量Si3N4和SiC的BN粉体，陶瓷转化率为38％。