MOLECULAR CLONING AND NUCLEOTIDE SEQUENCE ANALYSIS OF A TRANSFORMING GENE FROM HUMAN GASTROCARCINOMA CELL LINE

Mouse and rat fibroblasts were transfected with total DNA from human gastrocarcinoma cell line BGC-823. It was shown by hybridization assay that the genome of one of the rat secondary foci contains transforming genes from the human gastrocarcinoma cell line, which are homologous to the protooncogene c-Ha-ras in the normal cells. The genomic library of the rat secondary foci was constructed, using λ phage EMBL3 as the vector. The transforming gene Ha-ras of the human gastrocarcinoma cell was thus cloned by screening the library with the probes of human Alu repeat sequence and c-Ha-ras. The nucleotide sequences of the first and second exons were analysed by M13-dideoxy method. The result shows that the nucleotide sequence of the transforming gene is the same as that of the normal protooncogene except one nucleotide difference in the first exon.     

海涂柑桔缺铁敏感性差异机理研究

通过田间调查取样和砂培试验，分别测定不同桔苗砧穗组合的根系还原力和铁吸收动力学由，对比研究了海涂不同砧木柑桔缺铁失绿的敏感性差异。试验证明，抗缺铁能力较强的构头橙砧（Ｃ．ａｕｒａｎｔｉｕｍＬｉｎｎ）的桔苗的叶片中的“全铁”和“活性铁”含量和根系还原力均高于抗缺铁能力弱的枳砧（Ｐ．ｔｒｉｆｏｌｉａｔｅＬ．）桔苗；同时，其铁吸收动力学曲线表现出具有较大的Ｖｍａｘ和较小的Ｋｍ值；在ＨＣＯ３－逆境条件下，枳砧苗的Ｖｍａｘ下降较为明显，而构头橙砧的变化幅度相对比较小。     

扁桃酸甲酯对映体的毛细管电泳手性拆分

采用β-环糊精及其衍生物作为手性选择剂，对扁桃酸甲酯对映体进行毛细管电泳分离，考察了不同环糊精种类和浓度、背景电解质类型及pH对分离效果的影响；实验结果表明，pH6．0、50g／L磺酸化环糊精(Su-β-CD)、20mmol/L Tris的磷酸缓冲液，可以使扁桃酸甲酯对映体得到基线分离。     

离子液体对马肝醇脱氢酶催化特性的影响

本文研究了马肝醇脱氢酶（HLADH）在含6种离子液体（BMIm•Cl、BMIm•Br、BMIm•PF₆、BMIm•BF₄、BMIm•OTf和EMIm•Cl）反应体系中的催化特性。在含适当浓度离子液体BMIm•Cl、BMIm•Br、BMIm•PF₆和EMIm•Cl的体系中，HLADH催化乙醇氧化的活性高于不含离子液体的反应体系，但过高浓度离子液体的存在使HLADH的活性明显下降。在含BMIm•BF₄和BMIm•OTf的体系中，离子液体的存在均显著抑制HLADH的活性。离子液体分子中阴离子对HLADH的活性、动力学参数和活化能等均有明显影响。离子液体BMIm•Cl、BMIm•Br、BMIm•PF₆和EMIm•Cl的存在可以提高HLADH的热稳定性，而BMIm•BF₄和BMIm•OTf的存在则相反。此外，通过二阶紫外导数光谱对HLADH在含离子液体体系中构象的变化进行了研究。     

红外弱小目标的识别方法

红外弱小目标一直是自动监控和告警系统中的热点和难点。重点分析和介绍了红外弱小目标的探测、识别和跟踪算法。     

Electron–phonon coupling in topological insulator Bi_2Se_3 thin films with different substrates

Broadband transient reflectivity traces were measured for Bi_2 Se_3 thin films with various substrates via a 400 nm pump–white-light-probe setup. We have verified the existence of a second Dirac surface state in Bi_2 Se_3 and qualitatively located it by properly analyzing the traces acquired at different probe wavelengths. Referring to the band structure of Bi_2 Se_3, the relaxation mechanisms for photo-excited electrons with different energies are also revealed and studied. Our results show a second rise of the transient reflection signal at the time scale of several picoseconds. The types of substrate can also significantly affect the dynamics of the rising signal. This phenomenon is attributed to the effect of lattice heating and coherent phonon processes. The mechanism study in this work will benefit the fabrication of high-performance photonic devices based on topological insulators.     

不同基因型油菜苗期地上部硼分布及运转能力的差异探讨

通过大田试验，对低硼胁迫下不同基因型油菜地上部的硼分布和转动能力作了初步研究。结果表明：油菜苗期地上部各器官硼的分布以叶片最高，叶是硼胁迫反应敏感的器官。耐低硼迫品种间有差异。相对耐低硼胁迫的品种具有较强的硼吸收和转运能力。     

合金钢中镍的快速测定——丁二肟直接比色法

钢铁中镍的测定,常用方法是丁二肟比色法。铁和其它干扰元素多采用柠檬酸盐及酒石酸盐络合掩蔽。但由于它们与铁生成的黄色络合物在镍与丁二肟所形成的络合物最大吸收470毫微米处有较大的光吸收,因此不分离铁及其他干扰元素测定镍时,一般都是选择灵敏度较低的530毫微米处进行比色测定。根据兄弟单位的经验,我们采用焦磷酸钠掩蔽铁。通过实验表明,50毫克铁存在时,焦磷酸钠的合适     

甘草次酸及其衍生物的质谱研究

本文通过应用ＥＩ质谱和高分辨质谱对甘草次酸及其衍生物进行研究，阐明了分子离子的各种裂解、重排机理，讨论了主要离子的形成过程以及不同取代基对分子离子峰强度的影响。并用软电离手段──快原子轰击正、负离子（ＰＦＡＢ和ＮＦＡＢ）质谱，使ＥＩ谱上不出现分子离子峰的两个化合物而获得满意结果。     

聚焦泵浦条件下固体介质中受激布里渊散射过程的数值研究

 在非线性光学耦合波方程组中加入聚焦项，使之能够描述聚焦泵浦条件下的受激布里渊散射过程（SBS）。利用改进的SBS方程组，模拟了聚焦泵浦条件下熔石英玻璃棒中的SBS过程，给出了SBS反射率与泵浦激光能量的依赖关系，发现散射光脉冲中存在“聚焦刺”，并通过分析SBS诱导产生的应力场的特征对布里渊介质的安全性进行了评估，理论分析的结果与Yoshida等人的实验结果一致。