苦茶Camellia assamica var kucha Chang et Wang的嘌呤生物碱

用重量法和柱层析法从苦茶Ｃａｍｅｌｌｉａ ａｓｓａｍｉｃａ ｖａｒｋｕｃｈａ Ｃｈａｎｇ ｅｔ Ｗａｎｇ 的嫩梢中分离出３ 种嘌呤生物碱, 经薄层层析、熔点测定、元素分析、核磁共振和质谱等对其结构的测定,鉴定为咖啡碱、１ , ３ , ７ , ９四甲基尿酸和可可碱, 其百分含量分别为０８８％ , ０８４ ％ 和０２９ ％ ． 样品水提物经氯仿萃取后直接由高压液相色谱分析, 测得苦茶含咖啡碱１９３２ ９％ ,四甲基尿酸１２９４ １ ％ , 可可碱０５８５ ５ ％ , 茶叶碱００１２ ８％ ． 这是茶组植物中嘌呤生物碱新的分布模式     

海南吊罗山热带山地雨林植物种类多样性研究

海南吊罗山热带山地雨林扫把青冈 鸭脚木群落共出现44个科,95个属的乔木树种190种,其中种类数量大于5个的有樟科(24种),茜草科(17种),山毛榉科(17种),山矾科(11种)和山茶科(11种),主要属为新木姜属(6种),蒲桃属(6种),山矾属(12种)和栎属(13种).群落以热带分布型物种占优势,为895%.其中,又以热带亚洲分布成分最多,占358%;其次是泛热带分布,占274%;其它热带分布型占253%,群落中存在一定比例的温带分布型,约95%,中国特有分布属所占比例极低,仅为11%说明其物种的分化程度较低,同时,也说明山地雨林可能是一个广泛分布于东亚的常绿阔叶林的原始代表类型.样地1共有单个体种45种,双个体种20种,分别占物种总数的304%和135%;样地2共有单个体种46种,双个体种26种,分别占物种总数的383%和217%,这些低密度的或小种群的偶见种相对群落的主要种来说,更容易受到各种胁迫的影响而在群落中绝灭,从而使群落的物种多样性降低.     

异构计算的一种可移植编程模型及实现

介绍了异构计算的一种编程模型．该模型处理的对象是任意非一致的求解任务映射到任意非一致的系统结构上．文中分别给出了任务图的分簇算法,系统图的分簇算法和映射算法及实例．利用该模型可设计出可移植的并行程序,然后调度到可动态配置的异构计算机组织上运行     

中国石龙子消化道内容物中微生物的初步研究

从中国石龙子（Eumeceschinensis）胃、小肠和大肠中分离出的细菌包括枸橼酸杆菌属的弗劳地枸橼酸杆菌（Cirrobacterfreundii）和异型构枸橼酸杆菌（Citrobacterdiversus）、变形杆菌属的奇异变形杆菌（Proteusmiralelis）、肠杆菌属的阴沟肠杆菌（Enterobactercloacae）、芽孢杆菌属的枯草芽孢杆菌（Bacillussubtilis）、葡萄球菌属的表皮葡萄球菌（Staphylococcusepidermidis）和类杆菌属普通类杆菌（Bacteroidesvulqatus）．细菌在胃、小肠和大肠中分布数量为3．42×106、2．04×106和1．11×109．弗劳地枸橼酸杆菌为优势菌群．分离出的霉菌属于青霉属（Pencillium）、曲霉属（Aspergillus）和毛孢子菌属（Trichosporon）,主要是青霉属．在胃、小肠和大肠中霉菌的数量分别是2.19×104、1．67×104和1．61×104,酵母菌和放线菌都未发现．     

中国石龙子消化道内容物中微生物的初步研究

从中国石龙子（Ｅｕｍｅｃｅｓ ｃｈｉｎｅｎｓｉｓ）胃、小肠和大肠中分离出的细菌包括枸橼酸杆菌属的弗劳地枸橼酸杆菌（Ｃｉｔｒｏｂａｃｔｅｒ ｆｒｅｕｎｄｉｉ）和异型枸橼酸杆菌（Ｃｉｔｒｏｂａｃｔｅｒ ｄｉｖｅｒｓｕｓ）、变形杆菌属的奇异变形杆菌（Ｐｒｏｔｅｕｓ ｍｉｒａｂｉｌｉｓ）、肠杆菌属的阴沟肠杆菌（Ｅｎｔｅｒｏｂａｃｔｅｒ ｃｌｏａｃａｅ）、芽孢杆菌属的枯草芽孢杆菌（Ｂａｃｉｌｌｕｓ ｓｕｂｔｉｌｉｓ）、葡萄球菌属的表皮葡萄球菌（Ｓｔａｐｈｔｌｏｃｏｃｃｕｓ ｅｐｉｄｅｒｍｉｄｉｓ）和类杆菌属普通类杆菌（Ｂａｃｔｅｒｏｉｄｅｓ ｖｕｌｑａｔｕｓ）．细菌在胃、小肠和大肠中分布数量为３．４２ｘ１０~６、２． ０４ ｘ １０~６和 １． １１ｘ １０~９．弗劳地枸橼酸杆菌为优势菌群．分离出的霉菌属于青霉属（Ｐｅｎｃｉｌｌｉｕｍ）、曲霉属（Ａｓｐｅｒｇｉｌｌｕｓ）和毛孢子菌属（Ｔｒｉｃｈｏｓｐｏｒｏｎ）,主要是青霉属。在胃、小肠和大肠中霉菌的数量分别是２．１９ｘ１０~４、１．６７ｘ１０~４和１．６１ｘ１０~４,酵母菌和放线菌都未发现．     

添加碱金属氯化物的聚乙烯醇改性膜用于水乙醇渗透汽化分离

用碱金属氯化物对聚乙烯醇进行改性制得渗透汽化膜,并用于水乙醇渗透汽化分离．热分析结果表明：盐的加入增加了膜的热稳定性．膜的溶胀度的测试结果表明：随浸泡液中水含量增加,膜的溶胀度增大．渗透汽化结果表明：膜中含盐量对膜渗透汽化性能影响很大     

环（L-丙-L-脯）二肽的合成

以L-(+)-丙氨酸和N-叔丁氧羰基-L-(+)-脯氨酸为原料,分别经中和、缩合、脱保护、环化反应后,以65.3%的总产率合成得到了新型催化剂环(L-丙-L-脯)二肽,结构经IR、1HNMR、13CNMR、元素分析等表征.     

Asymptotic limits and stabilization for the 1D nonlinear Mindlin-Timoshenko system

<正> This paper shows how the so called von Karman model can be obtained as a singular limitof a modified Mindlin-Timoshenko system when the modulus of elasticity in shear k tends to infinity,provided a regularizing term through a fourth order dispersive operator is added.Introducing dampingmechanisms,the authors also show that the energy of solutions for this modified Mindlin-Timoshenkosystem decays exponentially,uniformly with respect to the parameter k.As k→∞,the authors obtainthe damped von Karman model with associated energy exponentially decaying to zero as well.     

Fluctuating stripes at the onset of the pseudogap in the high-T(c) superconductor Bi(2)Sr(2)CaCu(2)O(8+x)

Doped Mott insulators have a strong propensity to form patterns of holes and spins often referred to as stripes. In copper oxides, doping also gives rise to the pseudogap state, which can be transformed into a high-temperature superconducting state with sufficient doping or by reducing the temperature. A long-standing issue has been the interplay between the pseudogap, which is generic to all hole-doped copper oxide superconductors, and stripes, whose static form occurs in only one family of copper oxides over a narrow range of the phase diagram. Here we report observations of the spatial reorganization of electronic states with the onset of the pseudogap state in the high-temperature superconductor Bi(2)Sr(2)CaCu(2)O(8+x), using spectroscopic mapping with a scanning tunnelling microscope. We find that the onset of the pseudogap phase coincides with the appearance of electronic patterns that have the predicted characteristics of fluctuating stripes. As expected, the stripe patterns are strongest when the hole concentration in the CuO(2) planes is close to 1/8 (per copper atom). Although they demonstrate that the fluctuating stripes emerge with the onset of the pseudogap state and occur over a large part of the phase diagram, our experiments indicate that the stripes are a consequence of pseudogap behaviour rather than its cause.     

Comparative stability analyses of traditional and selective room-and-pillar mining techniques for sub-horizontal tungsten veins

The stability and productivity concerning a modification on the traditional room and pillar for a new selective technique at the Portuguese Panasqueira Mine have been described. The traditional room-and-pillar stoping uses 5.0-m wide rooms with 3.0 m×3.0 m pillars, while the selective room-and-pillar mining technique consists in stoping with rooms of 4.0 m wide and pillars of 4 m×4 m with a subsequent selective cutting of the quartz veins at the mid pillar of approximately 0.5 m high, to obtain a pillar section with an area of 3.0 m×3.0 m. The stability and productivity analyses indicate that the selective technique obtains smaller average pillar safety factor, more rock mass displacement, more extraction and selectivity ratios, and ore grade improvement, compared with the traditional technique. These results show that the selective technique is also more convenient. This proposed selective room-and-pillar mining technique is applicable to any sub-horizontal narrow quartz veins with wolfram, gold, etc. such as the famous La Rinconada gold mine in the Peruvian Andes.