Controlled growth of large-area, uniform, vertically aligned arrays of alpha-Fe2O3 nanobelts and nanowires

Vertically aligned iron oxide nanobelt and nanowire arrays have been synthesized on a large-area surface by direct thermal oxidation of iron substrates under the flow of O(2). The effects of reactive gas pressure, composition, and temperature have been systematically studied. It was found that nanobelts (width, tens of nanometers; thickness, a few nanometers) are produced in the low-temperature region (approximately 700 degrees C) whereas cylindrical nanowires tens of nanometers thick are formed at relatively higher temperatures (approximately 800 degrees C). Both nanobelts and nanowires are mostly bicrystallites with a length of tens of micrometers which grow uniquely along the [110] direction. The growth habits of the nanobelts and nanowires in the two temperature regions indicate the role of growth rate anisotropy and surface energy in dictating the ultimate nanomorphologies.     

1β—Methyl Carbapenem中间体的合成

综述了１β－Ｍｅｔｈｙｌ Ｃａｒｂａｐｅｎｅｍ中间体的合成方法，重点强调了如何构筑１位β构型的甲基。参考文献３７篇。     

POLYMER-PLATINUM COMPLEX CATALYSTS FOR OXIDATION OF METHANOL TO FORMALDEHYDE

Two kinds of polymer-platinum complexes: silica-supported poly-γ-diphenylphosphinopropylsiloxane-platinum complex and silica-supported polyphenylsilazane-platinum complex, have been found very active and selective in catalyzation of oxidation of methanol to formaldehyde at room temperature and under an atmospheric oxygen pressure. Their catalytic activities are greatly affected by P or N/Pt gram atomic ratio.     

助剂对Cu/Cr催化剂上甲醇部分氧化制氢的活性影响

曾研究了Cu/Cr二元催化剂上甲醇部分氧化制氢的反应，发现当Cu/Cr比为6：4时，催化剂的Cu^0比表面积最大，呈现出较好的活性。在Cu/Cr（6：4）催化剂中添加Fe,Zn,Al等8种助剂，考察其对甲醇部分氧化制氢催化性能的影响，并着重研究了Zn助剂的作用。实验结果表明，Zn的引入，有利于催化剂活性的提高。当Zn含量为10％时，催化剂活性最好。XRD表征结果表明，Cu/Cr催化剂的失活与其表面上的Cu物种烧结有关，Zn的引入可明显增强Cu/Cr（6：4）催化剂的热稳定性，提高其寿命。     

RECOGNITION SEQUENCE SPECIFICITY OF SIGNAL PEPTIDASE I AND THE ROLE OF SIGNAL PEPTIDE IN SECRETION OF PROTEIN IN Bacillus subtilis

By recombinant DNA technology, the N-terminal of the β-protein encoding region of plasmid pUBHO is fused with the structure gene of α-amylase from Bacillus licheniformis. This gene fusion is called βAmy. It is able to transcribe and translate in phase. Protein fusion can be secreted into the medium mediated by β-signal peptide. The efficiency of secretion is about 10% of the synthesized pre-α-amylase. By comparing the secretion capacities and analysing the restriction sites on β-Amy genes and the molecular weights of the mature α-amylase secreted by B. subtilis harbouring different plasmids, it is indicated in vivo that the recognition and cleavage sequence for signal peptidase I of B. subtilis is Ala-Ala-Ala Ala. The results also indicate that the secretion of the α-amylase in B. subtilis is in accordance with the post-translational transportation mode.     

四氢键二聚体和分子组装

介绍了最近几年新的四氢键有机二聚体研究的进展及其在分子自组装和分子聚 集体化学研究中的应用。     

泡沫铅对VRLA电池负极活性物质结构及性能影响

0引言随着36V/42V汽车电源系统的提出,新一轮汽车用电池的竞争不断加剧。从目前情况看,铅酸电池由于具有成本低廉,使用可靠,原材料来源丰富,铅回收率可高达98%等优点,因此成为电动车电源最实际的选择之一[1]。但作为电动车用电池,需要克服其比能量低、充电接受能力差和负极硫酸盐化等缺点。为此各国科学家开展了大量的研究工作。最近报道用铸造多孔体作为敞口铅酸电池的集流体,它的比表面积为14cm2·cm-3,正极活性物质利用率上升到50%,远高于传统的铸造板栅[2]。在铅酸电池集流体研究领域里另一个重大进步,就是以R V C(R etic-ulated V i…     

滂胺天蓝-氨基糖苷类抗生素的显色反应及其分析应用

在 pH2.0～7.0的条件下 ,滂胺天蓝(PSB)与硫酸卡那霉素(KANA)、硫酸庆大霉素(GEN)和硫酸新霉素(NEO)等氨基糖苷类抗生素反应生成蓝色离子缔合物 ,最大显色波长位于686～690nm ,线性范围分别为0～14.0、0～12.5、0～14.0mg/L ,摩尔吸光系数(ε)分别为1.53×104、1.12×104、1.47×104L/(mol·cm) ;最大褪色波长位于620～622nm ,线性范围分别为0～14.0、0～12.0、0～14.0mg/L ,摩尔吸光系数(ε)分别为1.41×104、1.43×104、2.42×104L/(mol·cm) ;当用双波长叠加法测定时 ,ε值分别为2.94×104、2.55×104、3.89×104L/(mol·cm) ;探讨了适宜的反应条件 ;该法用于市售药物中氨基糖苷类抗生素含量的测定 ,结果令人满意     

Research on Crystal Structure of the Complex of 10－Hydroxy－10－（3－indolyl）－9－phenanthrenone with Tetrahydrofuran

ＲｅｓｅａｒｃｈｏｎＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆｔｈｅＣｏｍｐｌｅｘｏｆ１０－Ｈｙｄｒｏｘｙ－１０－（３－ｉｎｄｏｌｙｌ）－９－ｐｈｅｎａｎｔｈｒｅｎｏｎｅｗｉｔｈＴｅｔｒａｈｙｄｒｏｆｕｒａｎＭｅｎｇＪｉ－Ｂｅｎ；ＷｅｎＺｈｏｎｇ；Ｗａｎｇ...     

聚（3—丁基噻吩）电导的热稳定性

研究了导电聚合物聚（３－丁基噻吩）（ＰＢＴ）在大气环境下的导电热稳定性。在室温至２２０℃范围内，测试电导率随时间及温度的变化。ＴＧＡ分析以及化学分析的结果表明：掺杂态的ＰＢＴ大约在１４０℃附近有一转化温度，低于或高于这一转化温度，电导率下降的决定因素各不相同。高于转化温度时，电导率下降的主要原因是反离子和高分子主链的解离，进而发生化学反应，影响了高分子主链的结构。ＸＰＳ测试结果表明：经热处理后的Ｐ