25 resultados para D.Z. Phillips

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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葡萄属(Vitis.L.)植物隶属于葡萄科(Vitaceae),主要分布于北温带,最南可以分布到南美洲的委内瑞拉和亚洲的越南以及印度北部。本文通过对该属分类研究历史的回顾,认为该属存在的问题主要表现在如下几个方面: 1)葡萄属自1753 年由Carl Linne创立以来,虽经planchon于1887年做了修订,但属的范围仍需进一步界定;2)在Planchon之后的100多年中未见有一全面的分类学修订工作,出现在该属的800多个名称需要考证;3)对一些广布种的变异认识不足,导致了大量可疑种。针对这些问题本文进行了如下几个方面的工作: l、形态学:通过大量的野外工作和标本观察,对该属植物的主要性状做了分析,讨论了这些性状状态在葡萄属中的变异规律及演化趋势,将灌木状习性、退化的卷须以及不裂的叶片视为进化的性状。 2、细胞学:利用前人对葡萄属(Vitis.L.)染色体数目的统计及一些杂交实验分析的结果,结合形态学等方面的特征分析,认为在葡萄科,染色体基数X=10为原始的,而x=19则为衍生的。葡萄属的染色体基数xl9(2n=38),多倍体较少见;麝香葡萄属[Muscadinia (Planch.) Sma11]的染色体基数为x=10 (2n=20).与蛇葡萄属、酸蔹藤属和爬山虎属的一致。葡萄属和麝香葡萄属间的杂种是不育的。 3、孢粉学:对葡萄属32种5变种及麝香葡萄属[Muscadinia (Planch.) Sma11]1种的花粉外壁做扫描电镜观察,结果发现花粉外壁雕纹在这两属间和葡萄属内变异较小,对区分属以及属下种上类群意义不大,但对种的鉴别有重要的价值。 4、植物化学:前人对植物化学的工作表明,植物的一些次生代谢产物如类黄酮化合物在葡萄科各类群中的分布规律较好地反映了各类群间的关系。这些结果较好地支持了Planchon对葡萄属范围的界定。 5、山葡萄复合体(V.amurensis complex)包括山葡萄(V.amurensis Rupr.)、燕山葡萄(V.amuresis Rupr. var. dissecta Skvorts.=var.yanshanensisD.Z.Lu et H.P.Liang)、百花山葡萄(V.baihuashanensis M.S.Kang et D.Z.Lu)、复叶葡萄(V.piasezkii Maxim.)、少毛复叶葡萄[V. piasezkii Maxux1.var. pagnuccii (Planch.) Rehd.]共3个种和2个变种,广泛分布于中国北方,形态变异较大。本文对该复合体做了形态分析,并用RAPD (Random Amplified Polymorphic DNAs)分子标记方法分析了这几个类群的关系。综合这些结果,归并了燕山葡萄和百花山葡萄。 在上述工作的基础上,我们得出了如下的结论: l、葡萄属在葡萄科中是一个进化的类群。整理后的葡萄属包括8系62种、l亚种和15变种,其中有2个新系、1个新组合系、2个新变种、1个新组合种和l3个新异名。 2、本文赞同SmaU在1903年作出的分类学处理,把麝香葡萄作为一个独立的属,比葡萄属原始但与葡萄属有着最近的亲缘关系。 3、依据形态特征和APD分析结果把山葡萄复合体的3个种2变种归并为2种l变种,即山葡萄、复叶葡萄和少毛复叶葡萄,认为分子标记技术在分析属内近缘种闻关系上很有价值。 4、葡萄属具有东亚和北美2个现代分布中心,该属可能起源于北美的东部,在晚白垩纪经白令陆桥散布至欧亚大陆。

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根据中国麻黄属植物分类及麻黄属起源和演化研究中存在的争论,本论文主要进行了分类学、形态学、微形态学、解剖学、形态发生学、孢粉学、古植物学、植物生态学和植物地理学等方面的研究。 1、分类学 从性状变异式样的分析入手,结合标本馆工作和野外调查,确认了中国麻黄属植物共有13个种;合并了丽江麻黄(Ephedra likiangensis)、雌雄麻黄(E. fedtschenkoae);澄清了前人在细子麻黄(E. regeliana)、灰麻黄(E. glauca)、草麻黄(E. sinica)和双穗麻黄(E. distachya)等种类鉴定中混乱的问题,并描述了一个新种——日土麻黄(Ephedra rituensis Y. Yang, D. Z. Fu et G. Zhu)。 2、形态学 提供了中国麻黄属种类的标本(包括模式标本)照片资料及中国麻黄属植物的雌球花和雄球花的照片资料,为麻黄属分类和系统学研究提供了证据。 3、微形态学 首次报道了中国麻黄属植物的种子表面微形态特征,聚合囊表面纹饰、小枝表面特征。 种子表面特征可分为4种类型。类型I:种子表面平滑,包括:中麻黄(Ephedra intermedia)、双穗麻黄、细子麻黄等;类型II:种子表面具疣状突起,仅发现木贼麻黄(E. equisetina)一种;类型III:种子表面具横向片层状突起,仅有斑子麻黄(E. rhytidosperma)一种;类型IV:种子表面具纵条纹,包括喜马拉雅特有的3个大种子的种类,即矮麻黄(E. minuta)、山岭麻黄(E. gerardiana)和藏麻黄(E. saxatilis)。 对小枝表面扫描电镜下的微形态构造的研究并没有发现前人报道的毛状体特征,而只有一些疣状角质突起和有变异的气孔,同时注意到,麻黄属植物的小枝表面特征受到生境、发育阶段的影响。 麻黄属聚合囊顶孔开口处具脑波状纹饰,而聚合囊表面纹饰具二级纹饰。麻黄属聚合囊表面纹饰非常独特,为该属在地层中雄性生殖构造的发现提供了可参考的性状。 4、孢粉学 补充了麻黄属中非常特化的种——斑子麻黄的孢粉资料,同时也对膜果麻黄(Ephedra przewalskii)、中麻黄、细子麻黄和木贼麻黄的孢粉重新进行了研究。结果表明斑子麻黄的花粉形态也非常特殊,其纵肋数目5条左右,纵肋波状扭曲,肋间沟槽内透明线发达且分枝。膜果麻黄的花粉与前人描述的一致,但是,中麻黄、细子麻黄和木贼麻黄的花粉形态可能受到发育的影响而与前人报道中描述的有些差异。讨论了麻黄属4种花粉类型的演化趋势。 5、形态发生学 对麻黄属雌球花三种代表类型的个体发育研究表明,三胚珠球花发育早期球花主轴的顶芽发育,双胚珠球花的顶芽没有发育,而在单胚珠球花中,雌性生殖单位直接占据顶芽的位置发育。这三种类型也代表了麻黄属球花演化的三个阶段,三胚珠球花代表麻黄属雌球花的原始式样,而单胚珠雌球花则为麻黄属雌球花最为特化的式样。总之,麻黄属雌球花有简化的趋势,伴随着这种趋势,雌球花苞片数目减少、种子数目减少、种子体积增大、表面复杂度增加。 6、解剖学 对斑子麻黄种子表面微构造的形态发生及解剖研究表明,斑子麻黄雌性生殖单位发育早期,其表面为平滑型,因此,突起为次生的。这些突起是由雌性生殖单位外盖被表皮细胞的外壁向外突出形成,这种突出生长常常在相邻细胞之间同时发生,因此,出现片层状构造。石蜡切片显示,这些突起在发育早期有完整的细胞核、细胞质等结构,但在种子发育晚期和成熟后,这些外壁突起的细胞成为空腔隙,本文对这种构造的生态学意义进行了分析。 7、古植物学 本文描述了早白垩麻黄科的2个大化石种。 古斑子麻黄(Ephedra archaeorhytidosperma Y. Yang, B. Y. Geng et D. L. Dilcher et Z. D. Chen)发现于辽西义县组尖山沟层,时代为早白垩的芭雷姆期。该种的雌球花具2对苞片、1或2枚种子、珠孔管短直或顶部稍弯、种子表面具横列片层状纹饰等特征而与现存的斑子麻黄特征最为相近。二者之间如此多的相似之处只有一种解释,那就是它们曾经有过共同祖先。因此,该种应归属于麻黄属的肉苞组。古斑子麻黄雌球花特征的稳定性同时也表明,在麻黄属中也存在所谓的“形态演化停滞现象(morphological stasis)”,而这种现象也是首次在买麻藤类植物中报道。 星学异麻黄(Alloephedra xingxueii J. R. Tao et Y. Yang)产于吉林大拉子组,时代属早白垩的阿普特期——阿尔布期。该种雌球花具2对苞片、2枚种子,种子长椭圆形且具短的珠孔管与现存麻黄科植物最为相近,但是,其分枝式样与麻黄属不同,因此,本文在麻黄科中建立了一新属新种。此外,麻黄科植物常被看作是干旱区植被的代表,但是,对星学异麻黄当时所处的环境研究发现,大拉子组当时具有较明显的亚热带气候条件下的植被性质,因此,星学异麻黄即使需要干旱的条件,可能也只是局部小生境的条件。 8、生态学和植物地理学 本文首次对麻黄属植物生存环境中的水热条件进行了调查。从所选择的8个分布点来看,除了拉萨外,在麻黄属生殖生长期,其余7个分布点的湿度均是一年中最底的时期,而温度在这个时期逐渐升高。 对各地区内麻黄属种类的分布情况的分析发现,麻黄属的种类主要集中在三个地区,一是我国西北、前苏联的中亚地区及邻近地区,二是美国西南部、墨西哥西北部的地区,三是南美的智利、阿根廷等地。

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The strain evolution of the GaN layer grown on a high-temperature AlN interlayer with GaN template by metal organic chemical vapor deposition is investigated. It is found that the layer is initially under compressive strain and then gradually relaxes and transforms to under tensile strain with increasing film thickness. The result of the in situ stress analysis is confirmed by x-ray diffraction measurements. Transmission electron microscopy analysis shows that the inclination of edge and mixed threading dislocations rather than the reduction of dislocation density mainly accounts for such a strain evolution. (c) 2006 American Institute of Physics.

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在综合文献报导的基础上,我们选择了LnMsbO_6和Ln_2M_2O_7 (M = Zr, Ti)做为研究体系,对其合成、组成、结构以及稀土离子在其中的发光性质进行了较为系统的研究。用氢氧化物共沉淀的方法,在等摩尔阳离子原料配比条件下,我们制备了LnMsbO_6和Ln_2M_2O_7(M = Zr, Ti, Ln = La - Yb, Y除Ce和Pm)。根据对组成的分析结果并与文献对比,我们认为得到的化合物组成与给出的分子式是一致的。由热分析并结合x-ray衍射分析对LnZrsbO_6的形成反应进行了研究,其结果表明化合物的形成过程是一个较慢的固相反应过程。通过x-ray粉沫衍射物相分析并结合掺杂Eu~(3+)的发光光谱,我们确定了在不同条件下合成的LnMsbO_6和Ln_2M_2O_7化合物的结构类型,并计算了所有化合物的晶胞参数。在对上述结构特性及其变化规律进行研究后,我们认为Ln_2M_2O_7结构变化规律与ΔZ/(d~2) (Z为阳离子电荷,d为阳离子与阴离距离)有关,随ΔZ/(d~2)值由小到大,Ln_2M_2O_7(M = Zr, Ti)先是形成具有荧石结构的阳离子无序固溶体,然后逐渐过渡到荧石结构的变型——有序的立方烧绿石结构,最后变型到单斜晶系结构。LnMsbO_6(M = Zr, Ti)低温相结构与Ln_2M_2O_7(M = Zr, Ti)是有联系的,即基本保持了其立方晶系结构。然后锑的加入使这种结构变得很不稳定,因此在高温灼烧下上述立方相将不可逆地变为更稳定的高温结构相。利用磁天平对LnMsbO_6和Ln_2M_2O_7进行了室温条件下的磁学性质测量,其玻尔磁子数的实验值与Van Vleck理论值符合较好。由此也可说以说明化合物的组成与给出的分子式是一致的。用荧光光谱仪对Eu~(3+)在不同基质中做发光光谱,其结果表明Eu~(3+)在烧绿石结构的Ln_2M_2O_7中,Ln~(3+)是处于具有反演中心的D_(3d)格位,这时~5D_0 → ~7F_2的电体极跃迁(~610nm)是被禁阻的,因此Eu~(3+)主要的发光为~5D_0 → ~7F_1磁体极跃迁(~590nm),并劈裂为两条谱线。在其它不具有反演中心的格位中Eu~(3+)的~5D_0 → ~7F_2跃迁则是较强的。在La~(3+)有着多个较低对称性格位的La_2Ti_2O_7:Eu中,无论是Eu~(3+)的激发光谱,还是发射光谱,其~5D_0与~7F_0之间的跃迁谱线都不只一条,这与La~(3+)多对称性格位特性是一致的。在立方荧石结构的LnZrsbO_6:Eu中,用Eu~(3+)电荷迁移带激发的发光光谱与用其它激发带激发的很不相同,其~5D_1能级的跃迁谱线非常强,我们认为这可能是由于电荷迁移激发态,将大部分能量传递给3~5D_1能级的结果。另外,我们比较了在Ln_2Zr_2O_7和LnZrsbO_6中Eu~(3+)的发光强度,发现前者要比后者强许多。在研究Bi~(3+)对Eu~(3+)的敏化作用时,我们发现在Y_2M_2O_7:Bi, Bu中Bi~(3+)对Eu~(3+)有较好的敏化作用,而在YMsbO_6:Bi, Eu中则没有。同时我们注意到对于Eu~(3+)取代六配位La~(3+)格位时,其电荷还移带位置和符合Hoefdraad认为是不变的规律,而是随着基质晶格的不同发生变化的。对Dy~(3+)在LnMsbO_6和Ln_2M_2O_7基质中发光性质研究中,我们看到Dy~(3+)的发光主要为兰色的~4F_(9/2) → ~6H_(15/2)跃迁(~480nm)和黄色的~4F_(9/2) → ~6H_(13/2)跃迁(~580nm)。其黄光与兰光的强度比值(R)随基质晶格的不同可以有很大的变化。一般情况下R值总是要大小1,且不随湿度和Dy~(3+)掺杂浓度变化。同时我们比较了在Ln_2Zr_2O_7和LnZrsbO_6 (Ln = Y, Gd, La)基质体系中Dy~(3+)的发光强度,发现同Eu~(3+)类似前者较后者强许多。在论文中我们给出了在Y_2M_2O_7和YMsbO_6 (M = Zr, Ti)中Sm~(3+)的激发光谱与发射光谱,从中可以看到当Sm~(3+)在Y_2Ti_2O_7中取代占据D_(3d)格位的Y~(3+)时,其~4G_(5/2) → ~6H_(9/2) (~650nm)电体极跃迁是被禁阻的。同时还给出了在YZrsbO_6中H_0~(3+)和Er~(3+)的激发光谱与发射光谱。此外,我们研究了Eu~(3+)和Dy~(3+)在一些基质体系中发光强度随温度的变化规律。发现Y_2Zr_2O_7:Eu的临界猝来温度要比La_2Zr_2O_7:Eu的高,Ln_2Zr_2O_7:Dy (Ln = La, Y)的温度猝来曲线则大致相同,且随温度和猝来要比Ln_2Zr_2O_7:Eu缓慢,对于上述现象我们利用位形坐标给出了一定的解释。然而所有的样品发光强度从室温开始,随温度的升高都是单调下降的。

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于2010-11-23批量导入

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干扰素(IFNs)是最早发现的具有广泛用途的一类细胞因子,IFN-α通过JAK/STAT信号途径调控机体一系列生理和病理反应。至今尚未发现类干扰素的小分子。我们前期研究发现天然产物毛蕊异黄酮可激活干扰素诱导的JAK/STAT信号途径。为发现类干扰素小分子、获得小分子探针,本课题拟建立成熟的JAK/STAT信号途径的筛选模型,合成毛蕊异黄酮及其类似物,研究这些化合物的构效关系,进而尝试通过共价键标记生物素或香豆素来直接研究它们与相关受体的作用。 从异香草醛出发经7步合成反应得到了毛蕊异黄酮。采用平行合成策略得到异黄酮类化合物;采用分支式合成策略,以取代苯乙酸作为合成砌块,获得具有与异黄酮类似结构的香豆素、3-芳基喹诺酮。与分离得到的黄酮类化合物,构建了一个包括异黄酮、黄酮、香豆素、3-芳基喹诺酮在内的化合物库。 建立了包含IFN-α刺激反应元件 (ISRE)的荧光素酶报告基因体系,通过筛选化合物库中的化合物,发现异黄酮骨架为激活JAK/STAT信号途径必须结构、毛蕊异黄酮7-位酚羟基被取代后活性丧失。根据以上结果,对毛蕊异黄酮3′-位标记物的合成进行了初步尝试。 发现山茱萸科植物青荚叶(Helwingia japonica (Thunb.) Dietr.)有抑制蛋白酪氨酸磷酸酯酶1B(PTP1B)的活性。从其地上部分95%乙醇提取物的乙酸乙酯部分分离得到5个化合物,应用波谱方法及与已知品对照的手段鉴定它们为p-menth-2-en-1β, 4β, 8-triol (Z-1)、blumenol A (Z-2)、2′,3′,4′,5′,6′-五羟基查尔酮(Z-3)、洋芹素7-O-β-D-吡喃葡萄糖苷(Z-4)、木犀草素7-O-β-D-吡喃葡萄糖苷(Z-5). Interferons (IFNs) are one kind of cytokines with broad functions. IFN-α mediates series physiological and pathological changes of human body via JAK/STAT pathway. Untill now, no IFNs-like small molecules are discovered. In our preliminary experiment, the natural product calycosin has been observed to activate JAK/STAT pathway. Therefore, we establish a luciferase reporter gene system and synthesize calycosin and its analogues to reveal their structure-activity relationship (SAR). Besides, in order to prove that calycosin activates JAK/STAT pathway through IFN receptor, we attempted to tag it with biotin or coumarin by covalent bonding. Calycosin was synthesized from isovanillin via seven steps. Other isoflavones were obtained by parallel synthesis; coumarins and quinolones were prepared through divergent synthesis, using substituted phenylacetic acids as building blocks. Combing with natural flavones, a small molecule library was established. A luciferase reporter gene system, consisting of 5 copies of the ISRE (interferon-stimulated response element), was used for screening of small molecules from that library. We found that the core-structure of isoflavone was necessary, and if the 7-OH is substituted, the activity slumps. According to our observation, we tried to tag biotin or coumarin at 3′-OH of calycosin. The 95% ethanol extract of the aerial parts of Helwingia japonica (Thunb.) Dietr. showed protein tyrosine phosphatase 1B (PTP1B) inhibitory activity. Five compounds were isolated. On the basis of spectral data or by comparison with authentic samples, they were identified as p-menth-2-en-1β,4β,8-triol (1), blumenol A (2), 2′,3′,4′,5′,6′-pentahydroxychalcone (3), apigenin 7-O-β-D-glucopyranoside (4), and luteolin 7-O-β-D-glucopyranoside (5).

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A Superconducting ECR ion source with Advanced design in Lanzhou (SECRAL) was successfully built to produce intense beams of highly charged ions for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. For 28GHz operation, the magnet assembly can produce peak mirror fields on axis 3.6T at injection, 2.2T at extraction and a radial sextupole field of 2.0T at plasma chamber wall. A unique feature of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. During the ongoing commissioning phase at 18GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.2kW and it turned out the performance is very promising. Some record ion beam intensities have been produced, for instance, 810e mu A of O7+, 505e mu A of Xe20+, 306e mu A of Xe27+, 21e mu A of Xe34+, 2.4e mu A of Xe38+ and so on. To reach better results for highly charged ion beams, further modifications such as an aluminium chamber with better cooling, higher microwave power and a movable extraction system will be done, and also emittance measurements are being prepared.

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The Lanzhou All Permanent magnet ECR ion source NO. 1 (LAPECR1) is the first all permanent magnet multiple ECRIS made in IMP. This ECRIS is running at 14.5GHz and can provide intense low charge state ion beams (varying from several to hundreds of e mu A) or medium charge state ion beams (varying from several to tens of e mu A). The size of source body is circle divide 102mmx296mm, the compactness and economical features enable the source suitable to be put on a HV platform or equipped by a small laboratory. This article gives the main parameters of the ion source.

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There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e mu A of O7+, 505 e mu A of Xe20+ 306 e mu A of Xe27+, and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

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In the present paper, a multifluid model of two-phase flows with pulverized-coal combustion, based on a continuum-trajectory model with reacting particle phase, is developed and employed to simulate the 3-D turbulent two-phase hows and combustion in a new type of pulverized-coal combustor with one primary-air jet placed along the wall of the combustor. The results show that: (1) this continuum-trajectory model with reacting particle phase can be used in practical engineering to qualitatively predict the flame stability, concentrations of gas species, possibilities of slag formation and soot deposition, etc.; (2) large recirculation zones can be created in the combustor, which is favorable to the ignition and flame stabilization.

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D-Serine, the endogenous coagonist of N-methyl-D-aspartate receptors (NMDARs), is considered to be an important gliotransmitter, and is essential for the induction of long-term potentiation. However, less is known about the role of D-serine in another for