N-(2'',3'',4'',6''-四乙酰基-β-D-吡喃葡萄糖基)-5-(4''-甲基联苯基-2-基)四氮唑的合成

5-(4’-甲基联苯基-2-基)四氮唑与2,3,4,6-四乙酰基-α-D-吡喃溴代葡萄糖在弱碱性条件下反应生成了β型的氮糖苷。产物结构经红外光谱、核磁共振光谱、质谱和元素分析得到了证实。     

红豆蔻挥发油化学成分的GC/MS法分析

用水蒸气蒸馏法从红豆蔻中提取挥发油．采用不同类型的毛细管柱进行分析，找出最佳分析条件，用归一化法测定其百分含量，并用气相色谱-质谱法对化学成分进行鉴定．鉴定得到48个成分，占挥发油总成分的84％以上．     

Cryptomelane（KxMn8-xO16）： Natural active octahedral molecular sieve（OMS-2）

The Xiangtan manganese deposit (XTM) used to be considered a supergene oxide manganese ore in South China. We reported a new identification of the naturally outcropping cryptomelane by examining the physical, chemical and structural features of the XTM supergene oxide manganese ore. The MnO2 content was over 90%, K2O more than 3%, and water from 2.2%-3.1% which is similar to one in zeolite. The cell parameters of the cryptomelane were given as a0 = 0.9974 nm, b0 = 0.2863 nm, c0 = 0.9693 nm and β= 91.47°. There was a larger pseduotetragonal tunnel in the natural cryptomelane that was formed by [MnO6] octahedral double chains with aperture of 0.462×0.466 nm2, filled with K cations resulting in some Mn3+ substituting for Mn4+ to balance the negative charges of structure. The finding is important not only for prospecting manganese resources in South China, but also in application of octahedral molecular sieve of natural cryptomelane as that developed in the tetragonal molecular sieve of natural zeolite o     

Preparation of (R)-and (S)-2-Allyl-1,3,2-Dinaphtho(α,β)[d.f]dioxaborepin and Their Reactions with Aldehydes

0　IntroductionEnantiopure 1,1′ bi 2 naphtholspossessingC2 chiralityhaveprovedtobeversatilechiralauxiliariesinanumberofasym metricreactions[1 \|6] .Althoughsomeboroncompoundsofthemhavebeenprepared[7 1 6] ,chemistryoftheirallylboranederivativeshasneverbeenreported .Toexplorepossibilityofapplyingseven memberedcyclicchrialallylboronateesterstoasymmetricsynthesisofchiralβ alkenylalcohols,whichareimportantintermediateinthepreparationofopticallyactivenaturalproducts,werecentlyat temptedtosynthesi…     

Climatic significance of stable carbon isotope in tree rings of Abies spectabibis in southeastern Tibet

The annually cross-dated stable carbon isotope of tree-ring a-cellulose of Abies spectabibis collected from the southeastern Tibetan Plateau is used to examine its rela-tionship with climatic parameters. The residual D13C series in treerings is constructed after removing the effects of age trend and rising CO2. We found a close relationship between D13C in tree rings and the relative humidity of September—November of the previous year measured at the nearby Ny-ingchi Meteorological Station, albeit a strong 搇agged effect? Thus we developed a transfer function to reconstruct the autumn relative humidity for the Nyingchi region, which explained 37.9% of the total variance (p < 0.001). Our results suggest a high frequency and moderate amplitude variance of the relative humidity before 1800, and the variance re-versed afterwards.     

论中西管理文化融合创新的趋同

中西管理文化的融合创新，应立足各自传统管理文化原创中的现代价值，结合世界经济一体化发展的需要，进行现代管理文化理念的创新，并且在管理实践融合创新的基础上实现理念与认识的趋同。     

土工格栅加筋路堤的三维有限元分析

运用通用有限元程序ANSYS ,对软弱地基上路堤加筋的作用和效果进行了三维有限元分析 .计算中采用DP模型模拟土体的材料非线性 ,采用面—面接触单元考虑筋土界面的状态非线性 ,并采用薄膜单元来模拟土工格栅 .通过对相关参数的敏感性分析 ,证明了土工格栅模量对加筋效果有显著影响 ,并且加筋位置靠近路堤底部时更能发挥加筋性能 ;证明了在土体发生显著侧向变形时土工格栅能够发挥抗拉效果 ,从而限制土体侧向变形和路堤外侧土体的隆起 ,达到减小沉降和不均匀沉降的效果 .研究成果对软弱地基路堤加筋处理和新老路基结合部处理均有借鉴意义     

试析高职英语教学存在的问题及解决对策

该文旨在通过对天津市部分高等职业技术学院的调研,分析高职学院目前英语教学的现状和存在的问题,力求探索出一条适合高职高专特色人才培养模式的英语教学改革新途径。     

基于树形模型的血管三维拓扑结构描述

针对磁共振血管成像的特点，提出了一个系统框架，将其中的血管表示为具有一定逻辑结构且保持原血管拓扑结构的特征树，先通过预处理提取出血管并进行三维细化，再递归跟踪血管骨架生成特征树并进行遍历提取出血管的分支点和端点．考虑到实际图像的复杂性，进一步引入森林来完全描述血管树．利用该系统可以进一步实现数字减影血管造影和磁共振血管成像的融合，并在此基础上实现脑血管的三维重建，对于临床血管图像的实验证明了该系统的可行性与有效性。     

用蛋壳制备柠檬酸-苹果酸钙的研究

介绍了1种利用蛋壳制备新型钙营养强化剂柠檬酸-苹果酸钙的方法。考察了蛋壳前期处理方法、煅烧条件、结晶方式等因素对产品产率及溶解度的影响。在结晶过程中引入冷冻法,结果表明,在-18℃下低温结晶对柠檬酸-苹果酸钙的产率及溶解度均有提高。用正交实验确定了反应时间为2h,反应温度为50℃,加水量为50mL,物质的量配比为n(蛋壳灰分):n(柠檬酸):n(苹果酸)=5:2:4的工艺条件,用该方法生产的产品产率可达到94.5％以上,并对产品进行了质量检验。