流动注射化学发光法测定大豆异黄酮

基于在NaOH碱性介质中,K3Fe(CN)6可以直接氧化大豆异黄酮产生强的化学发光这一现象,并结合流动注射分析技术,提出了直接化学发光测定大豆异黄酮含量的新方法。当K3Fe(CN)6浓度为5.0×10-4mol/L,NaOH浓度为0.5 mol/L,主副蠕动泵转数分别为45 r/m in和35 r/m in时,体系具有最强的化学发光。该方法测定大豆异黄酮的线性范围为1.0×10-3~0.5 g/L;其回归方程为A(峰面积)=193305C(mg/L) 229.97,r=0.9962;检出限为4.6×10-4g/L。对5.0×10-3g/L大豆异黄酮溶液连续测定,每次得3个峰值,重复7次,相对标准偏差为2.46%。本方法已用于大豆中异黄酮含量的测定。     

Hydrogen adsorption on zigzag (8,0) boron nitride nanotubes

The chemical adsorption of H atoms on an (8,0) zigzag boron nitride nanotube is studied using the density functional theory with the supercell method. One to four H atoms per 32 B and 32 N are considered. The results show that H atoms prefer to adsorb on the top sites of adjacent B and N atoms to form an armchair chain along the tube axis. An even-odd oscillation behavior of the adsorption energy of H atoms on the tube is found, and the average adsorption energy of even H atoms is obviously bigger than that of odd H atoms. The results can be understood with the frontier orbital theory. Based on this adsorption behavior, several high-symmetric structures of H adsorbed boron nitride nanotubes with 50% and 100% coverages are studied. The pairs of lines' pattern with 50% coverage has the biggest average adsorption energy per H(2) among the chosen configurations, corresponding to approximately 4 wt % hydrogen storage.     

三溴偶氮胂催化光度法测定痕量铁

本文研究了硫酸介质中痕量 Fe(Ⅲ)催化加速抗坏血酸、溴酸钾和三溴偶氮胂之间的褪色反应及动力学条件,建立了动力学光度法测定痕量Fe(Ⅲ)的新方法.方法灵敏度为1.82×10~(-12)g·ml~(-1).测定范围为Fe(Ⅲ)0～30ng/25ml.已用于人发和食品中痕量铁的测定.结果满意.     

科学仪器工作状态监测装置的设计与实现

建立了支持网络通讯的科学仪器工作状态监测装置。该检测装置以单片机系统为核心,运用信号检测技术获取仪器的工作状态信息,实现有效机时的记录。基于自制编码表对数据进行BASE64编码,保证了记录信息的安全;支持嵌入式互联网技术将被监测仪器的实时状态上传到远程服务器,实现大型科学仪器的网络化监测。     

EFFECT OF MOLECULAR WEIGHT OF PDMS ON MORPHOLOGY AND MECHANICAL PROPERTIES OF PP/PDMS BLENDS

 A series of polydimethylsiloxane (PDMS) with varied molecular weights (Mw = 3  106, 1  106 and 0.5  106) were melt blended with PP to investigate the effect of PDMS molecular weight (MW) on the morphology and mechanical properties of PP/PDMS blends. Scanning electron microscopic (SEM) examination showed that the size of PDMS domains was dependent on the MW of PDMS. It was found that the lower the value of PDMS MW, the better dispersion of the PDMS domains in the PP matrix. Tensile and Izod impact tests revealed that the addition of PDMS with lower MW would lead to a more significant increase in impact strength of the blends compared with the blends with higher MW ones, while the influence of the molecular weight on tensile strengths of the blends was relatively small in the MW range studied. Differential scanning calorimetry (DSC) results also showed that the crystallization temperature of PP was increased with decreasing PDMS MW, indicating a better nucleation capability of lower MW of PDMS. Melting flow rate (MFR) measurements indicated that the processibility of PP could be enhanced by adding PDMS, and again the lower MW PDMS resulted in better data. Our work demonstrates that not only the processibility but also the mechanical properties of PP could be enhanced to a more significant degree by using low MW PDMS than the higher ones.     

水热合成CdS纳米晶体的形貌控制研究

研究了水热合成CdS纳米晶体形貌的化学控制，选择不同的络合试剂为模板,研究其对水热合成CdS纳米晶体形貌的影响.实验发现若以络合试剂乙二胺、甲胺为模板时，产品CdS晶体的形貌分别为（20～30） nm×（200～600） nm和（40～50） nm×（200～600） nm尺寸的纳米棒;而以络合试剂吡啶、 氨为模板时，产品CdS晶体的形貌分别为平均尺寸约30 nm和20 nm的纳米颗粒.用XRD、TEM、XPS、PL和Raman光谱等技术对所得CdS纳米棒进行了表征.同时对水热合成CdS纳米晶体形貌的模板控制机制进行了探讨，提出了一种水热合成CdS纳米棒的络合物结构诱导生长机理.     

二氧化碳同环氧丙烷交替共聚用催化剂的研究

探讨了有机金属催化剂的组成及其对二氧化碳同环氧丙烷交替共聚产物结构的影响,发现二乙基锌—助剂体系的催化活性按如次顺序递降:二乙基锌—连苯三酚>二乙基锌—间苯二酚>二乙基锌—对苯二胺>二乙基锌—亚乙基脲。若用三异丁基铝代替二乙基锌同连苯三酚构成催化剂,则失去对二氧化碳同环氧丙烷交替共聚反应的活性同时,著者发现二乙基锌—二元芳胺催化体系与二乙基锌—二元酚催化体系的催化活性规律完全不同。     

甲胺化反应催化剂稀土改性丝光沸石的研究

研究了稀土改性丝光沸石催化剂对常压固定床上甲胺化反应的活性及选择性的影响，结果表明，以钇改性丝光沸石催化剂的活性及对二甲胺的选择性最佳。催化剂表征结果表明，稀土改性丝光沸石主要是引起丝光沸石中Ｂ酸中心发生变化，而对丝光沸石的晶体结构及表面硅铝原子比基本不产生影响。稀土改性能增强催化剂的热稳定性，延长催化剂的寿命。     

Microcalorimetric investigation of the growth of the <Emphasis Type="Italic">Escherichia coli</Emphasis> DH5α in different antibiotics

The effects of Amoxicillin Sodium and Cefuroxime Sodium on the growth of E. coli DH5α were investigated by microcalorimetry. The metabolic power-time curves of E. coli DH5α growth were determined by using a TAM air isothermal microcalorimeter at 37°C. By evaluation of the obtained parameters, such as growth rate constants (k), inhibitory ratio (I), the maximum heat power (P _m) and the time of the maximum heat power (t _m), one found that the inhibitory activity of Amoxicillin Sodium vs. E. coli DH5α is enhanced with the increasing of the Amoxicillin Sodium concentration, and the Cefuroxime Sodium has a stimulatory effect on the E. coli DH5α growth when the concentration is about 1 μg mL⁻¹. The IC₅₀ for the Amoxicillin Sodium and the Cefuroxime Sodium are 1.6 and 2.0 μg mL⁻¹, respectively, it implicates that the E. coli DH5α is more sensitive to Amoxicillin Sodium than Cefuroxime Sodium.