双掺(Tm3+,Tb3+)LiYF4激光器1.5 μm波长激光阈值分析

由速率方程推出了双掺（Tm^3 ,Tb^3 ）离子准四能级系统的激光阈值解析式，讨论了Tm^3 和Tb^3 离子之间的相互作用。分析了1.5μm波长附近的激光阈值和Tm^3 、Tb^3 离子的掺杂原子数分数及晶体长度的关系。结果表明，对于对应Tm^3 离子^3H4→^3F4跃迁的约1.5μm波长的激光，激活离子Tm^3 的掺杂原子数分数过大时，交叉弛豫作用将使系统阈值迅速增加。Tb^3 离子的加入，一方面能抽空激光下能级，起到降低阈值的作用；另一方面亦减少了激光上能级的寿命，使阈值升高。故Tb^3 离子有最佳掺杂原子数分数。对于Tm原子数分数为y=0.01的Tm:LiYF4晶体，Tb^3 离子的最佳掺杂原子数分数为0.002左右，同时表明，激光阈值与晶体长度有关。最佳晶体长度与Tm^3 、Tb^3 离子的掺杂原子数分数以及晶体的衍射损耗和吸收损耗有关。     

与HBV X蛋白相互作用的细胞蛋白的筛选及其鉴定

参考GenBank核苷酸序列库中的HBV的核苷酸序列设计合成了一对对应于HBx基因的引物，从原发性肝癌(hepatocellular carcinoma，HCC)患者的血清中提取HBV基因组DNA作为模板，扩增HBx编码区并测定了核苷酸序列．将该编码区克隆到酵母双杂交系统的诱饵蛋白表达载体pGBKT7中，转入酵母细胞AH109，进行表型鉴定．然后通过Mating实验从已制备好用于酵母双杂交系统的肝cDNA表达文库中筛选与HBx相互作用的细胞蛋白，并用体外免疫共沉淀实验进一步验证．研究表明，分离得到的与HBx基因编码的蛋白相互作用的4种新的细胞蛋白，分别是醛缩酶B、C8α亚基、一种丝氨酸蛋白酶Hepsin和一种未知蛋白．     

乳糖修饰壳聚糖微载体的制备及对培养肝细胞代谢活性的影响

液体石蜡作分散介质。戊二醛作交联刑，通过反相悬浮聚合制备了微米级的壳聚糖微载体．环氧氟丙烷活化后，乳糖进行修饰．用孔糖修饰的微载体进行原代大鼠肝细胞培养，利用相差显微镜对培养细胞进行形态观察，并测定肝细胞的代谢活性，结果显示，乳糖修饰壳聚糖微载体是一种优良的肝细胞培养支架．     

Kinetic Studies on the Reaction of Sodium Hexa-cyanoferrate(II) Complex with Peroxydisulfate Anion

Introduction In the previous studies on the oxidation reaction,peroxydisulfate was widely used as an oxidizingagent.1-5 One of the advantages of this oxidant lies in itsstability in a wide range of pH values. The reaction be-tween Fe(CN)5L3- (L=N-aromatic heterocyclic li-gands) and S2O8 2- has been proved to proceed throughan outer-sphere electron transfer mechanism.5 For a re-action [(Eq. (1)] to be under an outer-sphere mechanismthe steps involved are the formation of a reactant …     

The Isoelectric Point and the Points of Zero Charge of Fe-Al-Mg Hydrotalcite-like Compounds

The relation of the isoelectric point (IEP) and the point of zero net charge (PZNC) of the hydrotalcite-like compounds was discussed. It was found that the IEP does not equal to the PZNC and the IEP is higher than the PZNC. The structural positive charges existing in the HTlc,which cause the difference between the IEP and the PZNC. The effects of the structural positive charges of the HTlc on its IEP and PZNC are the same as the specific adsorption of metal cations.     

Mass Spectral Fragmentation of (S,S)-N,N′-Bis [1-(hydroxymethyl)alkyl]anthracene/Naphthalene-1,8-dicarboxamides under Electron Impact Ionization Conditions

IntroductionN,N′-Bis [1-( hydroxymethyl) alkyl] dicarboxa-mides are important intermediates for the syntheses ofbis-oxazolines, which are a class of the most importantand widely used ligands in catalytic asymmetric reac-tions[1,2]. On determining the str…     

一个在水稻胚胎中差异表达基因的分离鉴定

通过筛选水稻开花后48～50h的原胚和120～122h的分化胚的cDNA文库,得到一个在胚胎发育过程中表达有差异的克隆,命名为OsEES,测序结果显示OsEES含有一个预测的亚精氨合成酶结构域,编码一个大小约38×103(pI6.5)的蛋白.同时RNA原位杂交的结果显示开花48～50h的原胚中的信号强度明显大于开花120～122h的分化胚,表明OsEES可能在水稻胚胎发生过程中起到一定的调控作用.     

丝瓜种子萌芽及子叶生长过程中谷氨酰胺合成酶同工酶的变化

测定了丝瓜种子萌芽及子叶不同生长阶段的谷氨酰胺合成酶(GS)的活性及其同工酶的变化．除了发育上的变化外，光和外源氮对GS活性及其同工酶影响也是显著的．无论外源氮(N)是否存在，GS活性在种子萌芽和子叶生长初期是逐渐升高的，于第6天达到最大，其后活性逐步降低．在光照下，外源氮对GS1诱导作用大于GS2；在无氮下，光对GS2的刺激大于GS1；在暗处，外源氮对GS1和GS2两者都有诱导作用．     

光电变色器件用纳米晶氧化钛薄膜的微结构与特性

纳米晶TiO2薄膜在光电变色器件中具有很重要的作用。它的微结构直接影响染料的吸附、光的散射以及电荷输运的特性。因此，探索TiO2薄膜的微结构(如粒径、表面形貌和厚度等)及光电性能是非常有意义的。采用电子束蒸发工艺制备了光电变色器件用纳晶TiO2薄膜，利用原子力显微镜、X射线衍射、俄歇电子能谱等手段对纳米晶TiO2薄膜的表面形貌、结晶状态及组分进行了分析。从理论上研究和讨论了纳米晶TiO2薄膜晶粒尺寸对光电性能的影响，并用量子限制效应解释了吸收光谱峰值波长随粒径减小而发生蓝移的现象。     

Molecular Spectroscopic Study on the Interaction between Heparin and Neutral Red

The interaction between heparin and neutral red was investigated by molecular spectroscopic methods. The change of all spectra suggested that positively charged neutral red had interacted with negatively charged heparin. The study of influence factors indicated that electrostatic force and hydrophobic bond might be involved in the interaction. The total binding number per disaccharide unit and intrinsic binding constant were obtained using Scatchard model.