Single event transient characterization of SiGe HBT by SPA experiment and 3-D process simulation

Science China Technological Sciences - The single-photon absorption induced single event transient in the silicon-germanium heterojunction bipolar transistor is investigated. The laser wavelength...     

电感耦合等离子体质谱法(ICP-MS)测定镍钴锰酸锂中的金属铁

采用磁棒对镍钴锰酸锂中金属铁进行富集,再利用盐酸溶解金属铁,利用电感耦合等离子体质谱法(ICP-MS)测定镍钴锰酸锂中金属铁含量。研究了仪器的最佳测量条件、元素测定的质量数以及酸度的影响。方法测定结果准确、可靠,样品加标回收率在98.9%~104.1%。     

Expression of expansin gene, MiExpA1, and activity of galactosidase and polygalacturonase in mango fruit as affected by oxalic acid during storage at room temperature

An expansin gene, MiExpA1, from mango fruit (Mangifera indica L. cv. Zill), which had highest homology with MiExpA1 from cv. Dashehari by 96.43% in nucleotide sequence and 95.79% in amino acid sequence, was cloned and characterised. Moreover, effects of oxalic acid on MiExpA1 expression and enzymatic activities of α-galactosidase (α-Gal), β-galactosidase (β-Gal), and polygalacturonase (PG) were investigated after Zill fruit were dipped in 5 mM oxalic acid solution for 10 min and then stored at 25 °C. Application of oxalic acid significantly inhibited decrease in flesh firmness, notably suppressed and delayed MiExpA1 expression in the peel and the flesh, and also significantly decreased activities of these pectolytic enzymes in the flesh. It was suggested that these effects of oxalic acid might collectively contribute to alleviating cell wall disassembly, thereby slowing the process of softening and ripening in mango fruit during storage.     

超细粉碎中的机械力化学效应

我国地大物博,矿产丰富,但由于缺乏超细粉体加工技术设备,每年要花费数十亿美元进口国内所需的各种超细粉体材料。工业矿物加工成超细粉体后,可产生高额的附加值。如普通钾长石80元／t,当〈43μm,5000元／t。目前超绌粉体的制备方法有化学合成法和机械粉碎法。化学合成法以离子、分子为核心,生成并长大为超细粒子,该法易于制得小于1μm的超细粒子,粒度分布也可控制,但能耗高、过程复杂、经济性差、产量低、成本高,该方法仅限于制备某些特殊的功能材料,如超细金红石型二氧化钛粉体、超细碎性氧化铁粉等。     

唐钢FTSC工艺薄板坯连铸机的自动化控制系统

介绍了唐钢FTSC工艺薄板坯连铸机自动化控制系统的组成结构,详细阐述了控制系统实现的各种功能,重点讨论了几个主要控制项目在薄板坯连铸中的应用.