Mosaic and gradient SiGe single crystals for gamma ray Laue lenses

Both Ge_1−x Si _x mosaic crystals and Si_1−x Ge _x crystals with gradient of composition could be grown using the modified Czochralski technique to produce the diffracting elements for the MAX gamma ray telescope. Although many elements cut from the mosaic crystal and used before for CLAIRE gamma ray telescope had an efficiency up to 20%, the overall efficiency of the lens was about 8.1 ± 0.7 %, which is more than twice lower than the theoretically predicted efficiency. Some causes of this behaviour are discussed. In addition to mosaic crystals, the growth of Si_1−x Ge _x crystals with a gradient of composition and their properties are analysed. Such composition-gradient crystals could be a promising way to improve the diffraction efficiency of Laue lens for MAX.     

X射线荧光光谱法测定锌铝硅合金中硅和铁

采用岛津MXF-2400型多道X荧光光谱仪测定锌铝硅合金中硅及铁的含量,对样品分析面进行了选择,考察了分析面光洁度、样品放置时间对测定的影响条件。方法样品前期处理简便,分析速度快,灵敏度高,硅和铁的相对标准偏差(RSD,n=11)分别为1.15%和0.44%。与其他方法对照,结果相符。     

利用高精度重磁法对“羊里磁异常”的解释探讨

"羊里磁异常"自1967年发现以来,由于所处地质环境为矽卡岩型铁矿成矿有利地段,且紧邻已知的温石埠铁矿,以及"羊里磁异常"规模较大且具备低缓磁异常的特点,一直受到地质界的广泛关注,地勘单位在该区做了大量的铁矿找矿工作,但对"羊里磁异常"勘查中一直未取得突破性进展,该文从高精度重磁角度对"羊里磁异常"进行了定量解释以及定量计算,并通过钻探验证等技术手段,进一步推断"羊里磁异常"是由古近纪含磁铁碎屑的砂砾岩以及闪长岩共同引起的,对该异常的认识更进了一步。     

Nutrient compositions of cultured Thalassiosira rotula and Skeletonema costatum from the Jiaozhou Bay in China

Carbon, nitrogen, phosphorus, silicon composition of cultured two different sized phytoplankton common species of Thalazsiosira rotula and Skeletonema costatum from the Jiaozhou Bay were measured. Carbon, nitrogen, phosphorus, silicon contents in cell were obvious higher in T. rotula than in S. costatum, but the percents of nitrogen, phosphorus, sihcon contents in cell dry mass in T. rotula were lower than those in S. costatum. The dry mass concentrations of nitrogen,phosphorus, silicon in S. costatum were much higher than those in T. rotula, particularly silicon, the former was 6. 4 times of the latter, showing that S. costatum could more assimilate these elements. Especially, S. costatum had competitive dominance for assimilating silicon, which is beneficial to its becoming a major dominant species in relative short silicon of the Jiaozhou Bay. There were some differences in numerical value of nutrient ratios both laboratory-cultured phytoplankton and different sized suspended particulates （ mainly phytoplankton） in the Jiaozhou Bay, which was caused by the changes of environment. High contents of carbon, nitrogon and relative low phosporus, sil- icon, high molar ratio of nitrogen to phosphorus （far higher than Redfield value） and low ratio of silicon to phosphorus and silicon to nitrogen （far lower than Redfield values） in the two diatoms and different sized suspended particulates were consistent with those in the seawater. Relative short silicon in the seawater and phytoplankton showed that silicon was possibly affectting phytoplankton growth in the Jiaozhou Bay.     

MICP技术联合多孔硅吸附材料对锌铅复合污染土固化/稳定化修复的试验研究

近年来,工业和科技的快速发展使得重金属污染土固化/稳定化的修复研究成为热点。运用微生物诱导碳酸钙沉淀(MICP)技术联合吸附材料对锌铅复合重金属污染土进行固化/稳定化的修复,通过无侧限抗压强度试验、毒性浸出试验,评价处理前后污染土的固化效果与重金属的稳定化效果,结合扫描电镜(SEM)和X射线衍射(XRD)等检测手段,揭示MICP技术处理锌铅重金属污染土的修复机制。研究结果表明,采用MICP技术对锌铅重金属污染土进行固化/稳定化之后,可以有效降低污染土中有害重金属的浸出性。当矿化时间为10d时,试样无侧限抗压强度为942.5k Pa;铅的浸出浓度为4.20mg/L,比未处理时降低了44.81%;锌的浸出浓度为4.31mg/L,比未处理时降低了46.19%,效果显著。在此基础上,添加10%的多孔硅吸附材料后,试样无侧限抗压强度可达到1 021 kPa,强度提高了8.3%;铅的浸出浓度为2.45mg/L,与未经处理时相比,降幅达到了67.81%,与单纯MICP方法处理时相比,铅浸出浓度被二次降低了41.67%;锌的浸出浓度仅为2.93 mg/L,与未经处理时相比,降幅达到了63.4%,与单纯...     

硅钼黄分光光度法测定地下水中偏硅酸的不确定度评定

采用不确定度连续传递模型,对硅钼黄分光光度法测定地下水中偏硅酸(DZ/T0064.62—93)的不确定度进行评定。测量结果的不确定度主要来源于标准溶液引入的不确定度、曲线拟合产生的不确定度和测量过程引入的不确定度三部分,而二氧化硅和偏硅酸的摩尔质量不确定度较小,可以忽略不计。采用双误差回归的方式对标准曲线进行拟合,在对各个不确定度分量进行量化的基础上,通过合成得到测量结果的标准不确定度,再乘以95%置信概率下的扩展因子2,得到测量结果的扩展不确定度。     

天然粉石英的开发利用及深加工

介绍了粉石英的基本性能，概括了粉石英在工业中的应用，研究了提高粉石英表面活性的方法，进一步揭示了粉石英作为填料的潜在应用价值。     

云南梅树村前寒武系-寒武系界线剖面硅同位素研究

云南梅树村前寒武系-寒武系界线剖面是研究前寒武系-寒武系界线层型最重要的国际候选剖面之一。本文首次系统地研究了硅同位素在剖面中的变化规律,指出“C”点附近“界线粘土层”为火山成因,“B”点至“C”点之间有海底喷气活动;“C”点附近的δ~(13)C,δ~(18)O负异常与生物大量活动有关,而非“灾变”所致。     

中国的天然硅铁矿

硅铁矿属于罕见的Ｓｉ和Ｆｅ的互化物类矿物，目前在自然界已发现并命名的此类矿物相的矿物有：古北矿（Ｆｅ＿３Ｓｉ）、喜峰矿（Ｆｅ＿５Ｓｉ＿３）、等轴硅铁矿（ＦｅＳｉ）、二磋铁矿（ＦｅＳｉ＿２）及苏硅铁矿（ａＦｅ＿３Ｓｉ）等５种。本文着重介绍我国自１９８０年以来在藏、甘、冀、苏、皖、新、辽、浙诸省区所发现的二硅铁矿及其连生矿物自然硅。