Distribution of Helium Isotopes in Western Pacific Upper Layer

3He/4He ratios in samples of sea water obtained at depths from surface to 300 m in the upper layer of the Western Pacific Ocean were measured by a mass spectrometer VG5400. The lateral and vertical distribution of He isotopes in the studied area was discussed in detail on the basis of 3He/4He ratios. Excess and depleted 3He. in relation to δ3He value of surface water in equilibrium with air has been discussed in the area, which may be mainly attributed to the incorporation of the North Pacific Intermediate Water with the Equatorial Upwelling and the exchange of water masses between the South China Sea and the Western Pacific, respectively. The present work in Western Pacific has also indicated that He isotopes may be used as a tracer for mixing processes of water masses and oceanic circulation.     

薄层色谱法在香兰素合成中的应用

应用薄层色谱法对愈创木酚、3－甲氧基－4－羟基扁桃酸和香兰素进行了分析，以硅胶GF254作为吸附剂，从几种溶剂系统中选出氯仿：乙酸乙酯：正丙醇：冰乙酸：水＝20：1：1：1：2溶液作为展开剂。建立了 香兰素的薄层扫描定量分析方法，测定波长为500nm，参比波长为570nm，线性范围为0．31－6．2μg。     

有机相中脂肪酶催化糖酯合成的研究

研究了有机相中脂肪酶催化以单糖和乙酸乙烯酯或乙酸酐为底物的糖脂合成反应。建立了定性、定量检测糖酯的方法，考察了７种脂肪酶催化糖酯合成的活力，发现来自假单孢菌属的ＰＳＬ１的活力最高。研究了ＰＳＬ１对不同单糖底物的选择性，发现对甘露醇的选择性最好，转化率可达９５％。研究了反应体系中的含水量对糖酯合成的影响，探讨了酶浓度和温度对反应的影响。     

三水合氯化镨与18C6在乙醇中的配位行为及配合物的合成与表征

采用半微量相平衡方法研究了ＰｒＣｌ_３·３Ｈ_２Ｏ－１８Ｃ６－Ｃ_２Ｈ_５ＯＨ三元体系在２５℃的溶解度，测定了各饱和溶液的折光率。在该体系中有三种比学计量的配合物形成，其化学组成为：２ＰｒＣｌ_３·１８Ｃ６·６Ｈ_２Ｏ·Ｃ_２Ｈ_５ＯＨ、４ＰｒＣｌ_３·３（１８Ｃ６）·１２Ｈ_２Ｏ和ＰｒＣｌ_３·１８Ｃ６·３Ｈ_２Ｏ，依据相平衡结果，合成了三种固态配合物，利用化学分析、ＩＲ、ＴＧ、ＤＴＧ、ＤＳＣ及电导研究了配合物的组成和性质。     

引领学生进入有机化学世界

初学有机化学的学生,普遍感到有机化学比较难学。通过改变有机化学的教学流程,使之更符合学生的认知规律。实践过程和结果表明,新的教学流程可以帮助更多学生学好有机化学的起始课。     

单核锌双卟啉配合物构象平衡的理论研究及光谱分析

合成了一系列以不同长度柔韧链相连的p/p型单核锌双卟啉配合物。选用Tripos力场,利用分子动力学模拟退火和分子力学构象搜索相结合的方法对该系列双卟啉进行了能量优化和构象分析。理论计算结果表明:该类双卟啉稳定存在的最低能量构象为叠合式,最高能量构象为伸展式,并存在一系列的中间能量构象;双卟啉分子内π-π作用和能量转移与双卟啉存在的两种主要构象密切相关;分析了分子内π-π作用的本质。运用不同光谱测试手段验证了理论计算结果: 利用可见和相应二阶导数吸收光谱研究了双卟啉主要存在的叠合式和伸展式构象,通过红外光谱观察了对双卟啉构象和卟啉环间π-π作用较为敏感的吸收谱带;利用荧光光谱计算了双卟啉的分子内能量转移效率。     

六六六异构体稳定碳同位素组成分析

采用GC-C-IRMS、EA-IRMS和Dual-inlet IRMS 3种稳定同位素比值质谱仪分别对六六六的α、β和γ3种异构体的稳定碳同位素组成进行了分析。对比3种分析系统测定的碳同位素组成数据表明GC-C-IRMS系统能够准确和精确地测定六六六碳同位素组成。应用GC-C-IRMS技术分析了水样品中α-和γ-六六六的碳同位素组成,结果表明六六六在溶解、稀释、萃取、挥发等过程碳同位素组成没有分馏现象。采用GC-C-IRMS技术分析环境样品中持久性有机氯农药稳定碳同位素组成可能得到广泛应用。     

Relationships among Preparative Technique,Phase Composition and Bending Strength of Bauxite Porcelain

1 INTRODUCTION Bauxite porcelain is a novel “K2O–Al2O3–SiO2” system ceramic by using sintered bauxite, clay and potash feldspar and albite as the main raw materials with the Al2O3’s content of 50%～60(massfraction). Compared to the traditional“K2O–Al2O3–SiO2” feldspar porcelain by using quartz, bolus alb and potash feldspar and albite as the main raw materials, the bauxite porcelain possesses such advantages as high mechanical strength, excellent electrical insula- tion prop…     

相转移催化应用于催化裂化汽油氧化脱硫的研究

随着人们环境保护意识的增强及原油硫含量的增大, 生产满足环境保护要求的清洁燃料是全球炼油工业的发展趋势, 燃料油脱硫显得越来越重要. 在众多的脱硫方法中, 选择性氧化脱硫技术以其工艺条件温和, 脱硫效果明显等特点, 受到了炼油行业的极大关注[1~3], 但脱硫率偏低(30％), 其关键是水相氧化剂与含硫化合物的有效混合. 本文将相转移催化应用于催化裂化(FCC)汽油的氧化脱硫中, 并对脱硫的工艺和机理进行了研究.     

非晶聚对苯二甲酸乙二醇酯薄片在低温退火过程中的声发射现象

Acoustic emission during sub-Tg annealing fort amorphous polyethylene terephthalate (PET) sheet quenched from melt has been observed. The mechanical properties, texture and glass transition of annealed specimens have been studied. It is shown that some of PET chains change from non-equilibrium state to equilibrium state during sub-Tg annealing, which leads to stress concentration in specimen. When the level of internal stress approaches to the limit, the acoustic waves are emitted due to sudden releasing of stress and the micro-defects are for-med. This is one of the important reasons,the causes the loss of mechanical properties to an-nealed specimens.