Detailed investigation of optimized alkali catalyzed transesterification of Jatropha oil for biodiesel production

The non-edible oils are believed to be one of the major feedstock for the production of biodiesel in future.In the present study,we investigated the production of Jatropha oil methyl esters(JOMEs) via alkali-catalyzed transesterification route.The biophysical characteristics of Jatropha oil were found within the optimal range in accordance with ASTM standards as a substitute diesel fuel.The chemical composition and production yield of as-synthesized biodiesel were confirmed by various analytical techniques such as FT-IR,1H NMR,13 C NMR and gas chromatography coupled with mass spectrometry.A high percentage conversion,～96.09%,of fatty acids into esters was achieved under optimized transesterification conditions with 6 :1 oil to methanol ratio and 0.9 wt% Na OH for 50 min at ～60°C.Moreover,twelve fatty acids methyl esters(FAME) were quantified in the GC/MS analysis and it was interesting to note that the mass fragmentation pattern of saturated,monounsaturated and diunsaturated FAME was comparable with the literature reported values.     

OP功能食品一宫廷强骨珍的研究

宫廷强骨珍是一种针对中老年人原发性骨质疏松症(osteoporosis,OP)的功能性食品。经检测分析,本品含有生物碱、皂甙、多糖、蛋白质、维生素D、维生素C、锗、硒、钙多种活性物质和营养素。经动物实验和临床验证表明,本品具有阻止骨质疏松的进程,能提高骨矿物含量,对OP防治作用显     

RADIOCHEMICAL INVESTIGATION OF MASS DISTRIBUTIONS IN 12C-INDUCED FISSION OF 209Bi AND 238U

The yields of 15 and 17 fission, products have been obtained by radiochemical determinations in ¹²C-induced fission of ²⁰⁹Bi and ²³⁸U respectively. From these data, the mass distributions of fission fragments are calculated based on three different hypotheses for the charge distribution. The results seem to indicate that the hypothesis of equal charge displacement gives the best fit to the Gaussian distribution for the masses of the fission fragments. By comparison with the mass distributions for ²⁰⁹Bi (¹²C, f), ²³⁸U(¹²C, f) and ¹⁹⁷Au(¹²C, f) in our early measurement, we find that for fission parameter Z²/A>37, the width of the mass distributions increases with Z²/A rapidly.     

An MP2 study on pre-reactive complexes (CH_2)_2O … XY (X,Y = H,F,Cl,Br,I)

The structures, energies, atomic chaiges and IR spectra of complexes (CH2)2O…XY (X, Y = H, F, Cl, Br, and I) have been examined by means of ab initio molecular orbital theory at the second-order level of Moller-Plesset perturbation correction. It is found that the hydrogen bond O…H-X is non-linear. The attraction between X and the H atoms in oxirane ring causes O…H-X bond bending. The hydrogen bond slighdy weakens the bond strength of C-O, and leads the bending and stretching mode of IR to shift to the red. The calculation results show that there is no evidence of a significant extent of proton transfer to give (CH2)2OH …X- in the isolated complexes.     

全氟并五苯在半金属Ga表面的分子二聚化及自组装单层

利用超高真空扫描隧道显微镜(UHV-STM)和有机分子束沉积(OMBD)方法研究了全氟并五苯(perfluoropentancene,PFP)分子在半金属Ga表面的吸附和两维自组装. 在低覆盖度下单个PFP分子在Ga表面上表现出很高的迁移性. 在1分子单层(monolayer, ML)时PFP分子发生二聚化并在 Ga 表面上无序排列. 轻度热退火可导致PFP两维自组装: 二聚体排列为高度有序的一维分子带阵列, 带中 PFP二聚体排列为砖墙(brick wall)结构. 在高分辨 STM图中, PFP分子两端出现亮暗相反的圆形突起, 并且相邻分子的亮暗极性相反, 表明PFP分子带有电偶极矩, PFP二聚体带有电四极矩. 因此, PFP分子二聚体的形成机制可唯像解释为反向电偶极矩之间的静电吸引作用; 二聚体的砖墙排列结构可归结为同向电四极矩之间的静电排斥作用.     

斯德哥尔摩公约新增持久性有机污染物的一些研究进展

2009年5月瑞士日内瓦举行的斯德哥尔摩公约缔约方大会第四届会议(COP-4)决定将全氟辛基磺酸及其盐类、全氟辛基磺酰氟、商用五溴联苯醚、商用八溴联苯醚、开蓬、林丹, 五氯苯, α-六六六、β-六六六、六溴联苯等九种化学物质新增列入公约附件A、B或C的受控范围. 目前, 相关领域专家正在进行包括短链氯化石蜡(short chain chlorinated paraffins, SCCPs)、硫丹(Endosulfans)及六溴环十二烷(Hexabromocyclododecanes, HBCDs)等化学品的评估以决定是否在下次会上讨论并最终进入受控名单. 斯德哥尔摩公约新增持久性有机污染物(persistent organic pollutants, POPs)是目前国际环境科学研究的热点领域, 同时其所引起的环境污染问题也是影响我国环境安全的一个重要因素. 随着公约新增持久性有机污染物审查工作的进展, 我国正面临履约及削减控制POPs的挑战. 对于新增POPs, 我国已陆续启动了相关的研究项目对其污染源解析、演变趋势、运移规律、生物累积及毒性效应等进行研究并取得了一定的成果. 本文拟介绍我国在新增POPs方面的部分研究进展并展望我国履约所面临的科研需求.     

Design, synthesis and characterization of novel biodegradable macrodiols based on poly（DL-lactic acid） and poly（p-dioxanone）

Integrating poly(lactic acid)(PLA),glycolic acid(GA) and ethylene glycol(EG) will hopefully result in a novel copolymer that combines such advantages as fastened and controllable release rate and improved flexibility together with good biocompatibility.In this study,p-dioxanone(PDO) was employed to copolymerize with DL-lactide(LA) via ring-opening melt polymerization using Sn(Oct)_2 as an initiator and ethylene glycol as a co-initiator.The obtained degradable macrodiols(HO-P(LA-co-PDO)-OH) were just such...     

土壤中十四种元素的ICP-AES和ISE的碱熔直接测定

报道了应用直读型电感耦合等离子体发射光谱(ICP-AES)及离子选择电极(Ion-SelectiveElectrode,简称ISE)成功地测定土壤中十四种难测元素的方法及其精度。土壤样品经过NaOH高温熔融、用水定容后,直接在强碱性溶液中用ICP-AES测定通常较难测定的十三种元素;Se、Mo、B、As、Si、S、Pb、P、Ge、Sn、Sb、Cr、K。通过ISE亦能很好地测定F。     

波长1O64nm脉冲激光高阈值反射膜的研制

研究 Ｈｆ Ｏ２／ Ｓｉ Ｏ２ 高反射膜的制备工艺及其激光诱导损伤阈值的比较测试,分别采用了反应蒸镀 Ｈｆ Ｏ２、反应离子辅助蒸镀 Ｈｆ Ｏ２、反应离子辅助蒸镀金属 Ｈｆ 的源材料形成 Ｈｆ Ｏ２ 薄膜。采用这三种工艺制备了 Ｈｆ Ｏ２ ／ Ｓｉ Ｏ２ 高反射膜,在中心波长 １０６４ｎｍ 处,反射率 Ｒ≥９９．５％ ,其中反应蒸镀 Ｈｆ Ｏ２ ／ Ｓｉ Ｏ２ 高反射膜损伤阈值最高,可达 ６０ Ｊ／ｃｍ ２（１０６４ｎｍ ,５ｎｓ）。     

宽带电信网络技术的发展

因特网的迅速发展给传统电信网带来了巨大冲击,也使电信界面临通信网未来如何发展的重大课题。本文重点对ＩＰｏｖｅｒＡＴＭ、ＩＰｏｖｅｒ ＳＤＨ和ＩＰ ｏｖｅｒＷＤＭ三种技术的特点、利弊得失及适用范围进行了详尽的介绍和分析。此外,文章还介绍了我国网络的发展现状,并在此基础上指出：我国目前应充分利用已投资建设的ＡＴＭ网络资源,在业务需求尚不十分明朗的情况下,应避免盲目扩大投资。