63 resultados para colombo itetris ns-3 VANET monitoraggio traffico veicoli ITS Intelligent Transport System


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The 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) isoenzymes play a key role in cellular steroid hormone synthesis. Here, a 3 beta-HSD gene homolog,was cloned from Rana grylio virus (RGV), a member of family Iridoviridae. RGV 3 beta-HSD gene has 1068 bp, encoding a 355 aa predicted protein. Transcription analyses showed that RGV 3 beta-HSD gene was transcribed immediate-early during infection from an initiation site 19 nucleotides upstream of the translation start site. Confocal microscopy revealed that the 3 beta-HSD-EGFP fusion protein was exclusively colocalized with the mitochondria marker (pDsRed2-Mito) in EPC cells. Upon morphological observation and MTT assay, it was revealed that overexpression of RGV 3 beta-HSD in EPC cells could apparently suppress RGV-induced cytopathic effect (CPE). The present studies indicate that the RGV immediate-early 3 beta-HSD gene encodes a mitochondria-localized protein, which has a novel role in suppressing virus-induced CPE. All these suggest that RGV 3 beta-HSD might be a protein involved in host-virus interaction. @ 2006 Elsevier Inc. All rights reserved.

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Crystalline poly (3-hexylthiophene) (P3HT) nanofibrils are introduced into the P3HT: [6, 6]-phenyl C61-butyric acid methyl ester (PCBM) composite films via P3HT preaggregation in solution by adding a small amount of acetone, and the correlation of P3HT nanofibrils and the optoelectronic properties of P3HT:PCBM bulk heterojunction photovoltaic cells is investigated. It is found that the optical absorption and the hole transport or the resulted P3HT:PCBM composite films increase with the increase of the amount of P3HT nanofibrils due to the increased P3HT crystallinity and highly interconnected nanofibrillar P3HT networks. However, it is also found that high contents of crystalline P3HT nanofibrils may restrain PCBM molecules from demixing with the P3HT component that forms electron traps in the active layer. and hence reduce the charge collection efficiency. Small contents of P3HT nanofibrils not only improve the demixing between P3HT and PCBM components, but also enhance the hole transport via crystalline P3HT nanofibrillar networks, resulting in efficient charge collection.

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The gas transport properties of a series polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) with 1,3-phenylenediamine or 3,5-diaminobenzic acid (DBA) or its esters are reported. The effects of carboxylic group (-COOH) and carboxylic ether groups (-COOR), at five positions of 1,3-phenylenediamine moiety, on H-2, CO2, O-2, and N-2 permeability, diffusivity, and solubility of the polyetherimides were investigated. The gas permeability, diffusion, and solubility coefficients of the polyetherimides containing COOR are bigger than those of HQDPA-PDA, but the ideal separation factors and ideal diffusivity selectivity factors are much smaller than that of HQDPA-PDA because COOR decreases chain segmental packing efficiency and increases chain segmental mobility. The permeability coefficients of HQDPA-DBA to H-2, CO2, and O-2 are bigger than those of HQDPA-PDA; the ideal separation factors for gas pairs H-2/N-2, CO2/N-2, and O-2/N-2 are also much bigger than those of HQDPA-PDA. Both the diffusion coefficients of CO2 and O-2 and the ideal diffusivity selectivity factors for CO2/N-2 and O-2/N-2 are bigger than those of HQDPA-PDA because COOH decreases both chain segmental packing efficiency and chain segmental mobility. The copolyimides, which were prepared from 3,5-diaminobenzic acid and 3,5-diaminobenzic esters, have both high permeability and high permselectivity. (C) 1997 John Wiley & Sons, Inc.

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<正> 引言 最近十多年,简化NS方程(以下记为SNS)的研究和计算有长足进展。由于在NS方程组中对粘性项的取舍不同,因而有几种不同的简化NS方程组,究竟哪种形式更合理,是需进一步探讨的一个问题。文献[1]利用原始NS方程及三种不同的简化NS方程组,对球的超音速绕流数值试验表明,其效果是不一样的。文献[3]也指出,如果SNS方程组的形式选择不当,会带来不可忽略的误差。从二维研究不难看出,目前广泛采用的三维SNS方程即粘性激波层方程组(VSL)及抛物化NS方程组(PNS),都不是最合理的简化形式。本文提出三维NS方程组的一种最好形式,称为修正的PNS方程组(记为MPNS),并论证它的合理性及精确度。

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A Nd:glass regenerative amplifier has been set up to generate the pumping pulse with variable pulse width for an optical parametric chirped-pulse amplification (OPCPA) laser system. Each pulse of the pulse train from a cw self-mode-locking femtosecond Ti:sapphire oscillator is stretched to approximate to300 ps at 1062 nm to be split equally and injected into a nonlinear crystal and the Nd:glass regenerative amplifier, as the chirped signal pulse train and the seed pulse train of the pumping laser system, respectively. By adjusting the cavity length of the regenerative amplifier directly, the width of amplified pulse could be varied continuously from approximate to300 ps to approximate to3 ns. The chirped signal pulse for the OPCPA laser system and the seed pulse for the pumping laser system come from the same oscillator, so that the time jitter between the signal pulse and the pumping pulse in optical parametric amplification stages could be <10 ps. (C) 2003 Society of Photo-Optical Instrumentation Engineers.

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研究了碱金属氟化物对掺Yb3+氟磷玻璃的光谱性质和析晶稳定性能的影响。运用倒易法计算了Yb3+的发射截面。结果显示,LiF的引入对吸收和发射截面的提高作用较大并出现最佳引入量极值,其次为KF。碱金属氟化物的引入可提高二元体系的析晶稳定性能,使玻璃网络结构得到改善;拉曼光谱显示二元体系中引入YbF3后玻璃网络结构得到增强,而在引入碱金属氟化物的三元体系中掺杂YbF3后破坏了网络完整性,降低系统析晶稳定性能。

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For an orthotropic laminate, an equivalent system with doubly cyclic periodicity is introduced. Then a 3-dimensional finite element model for the equivalent system is transformed into the unitary space, where the large finite element matrix equation is decoupled into some small matrix equations. Such a decoupling very efficiently reduces the computational effort. For an orthotropic laminate with four clamped edges, no exact elasticity solution is available, and the deflection values predicted by different methods have a considerable difference each other for a small length-to-thickness ratio. The present predictions are the largest because the present method is a full 3-dimensional finite element analysis without superfluous constraints. Illustrative numerical examples are presented to observe the distributions of stresses through the thickness of the laminates. (C) 2010 Elsevier Ltd. All rights reserved.

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A series of complex perovskite solid solutions of Ba[(Mg1-xCdx)(0.33)Nb-0.67]O-3 have been synthesized by the columbite method. Detailed Rietveld refinement of their X-ray diffraction data show that Ba[(Mg1-xCdx)0(.33)Nb(0.67)]O-3 has an order trigonal structure. The ordering degree as determined by the B-site occupancies increases with the partial substitution of Cd for Mg.

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A novel electrogenerated chemiluminescence (ECL) sensor based on Ru(bpy)(3)(2+)-doped silica (RuDS) nanoparticles conjugated with a biopolymer chitosan membrane was developed. These uniform RuDS nanoparticles ( similar to 40 nm) were prepared by a water-in-oil microemulsion method and were characterized by electrochemical and transmission electron microscopy technology. The Ru( bpy)(3)(2+)-doped interior maintained its high ECL efficiency, while the exterior nanosilica prevented the luminophor from leaching out into the aqueous solution due to the electrostatic interaction. This is the first attempt to branch out the application of RuDS nanoparticles into the field of ECL, and since a large amout of Ru(bpy)(3)(2+) was immobilized three-dimensionally on the electrode, the Ru( bpy)(3)(2+) ECL signal could be enhanced greatly, which finally resulted in the increased sensitivity. This sensor shows a detection limit of 2.8 nM for tripropylamine, which is 3 orders of magnitude lower than that observed at a Nafion-based ECL sensor. Furthermore, the present ECL sensor displays outstanding long-term stability.

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合成并表征了聚(苯乙烯(S)-丙烯酸(A))镨配合物(SAAC·Pr)。红外光谱表明它具有双配位结构:Pr?C—R。计算了共聚物中单体单元的序列分布。苯乙烯和丙烯酸单元长序列分布随其在共聚物中含量的增加而增加。当丙烯酸长序列分布高时,配合物的催化活性低。苯乙烯和丙烯酸的平均链长分别为ns=3,nA=1时,配合物的催化活性最高。

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Negabinary is a component of the positional number system. A complete set of negabinary arithmetic operations are presented, including the basic addition/subtraction logic, the two-step carry-free addition/subtraction algorithm based on negabinary signed-digit (NSD) representation, parallel multiplication, and the fast conversion from NSD to the normal negabinary in the carry-look-ahead mode. All the arithmetic operations can be performed with binary logic. By programming the binary reference bits, addition and subtraction can be realized in parallel with the same binary logic functions. This offers a technique to perform space-variant arithmetic-logic functions with space-invariant instructions. Multiplication can be performed in the tree structure and it is simpler than the modified signed-digit (MSD) counterpart. The parallelism of the algorithms is very suitable for optical implementation. Correspondingly, a general-purpose optical logic system using an electron trapping device is suggested. Various complex logic functions can be performed by programming the illumination of the data arrays without additional temporal latency of the intermediate results. The system can be compact. These properties make the proposed negabinary arithmetic-logic system a strong candidate for future applications in digital optical computing with the development of smart pixel arrays. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)00803-X].

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在“神光-Ⅱ”装置上进行先进高能多功能激光束系统(简称第九路)研制工程中,由于在原ICF靶室上又增加了输入“汤姆逊探针光”和“X光背光照明探针光”的锥形真空套筒及其终端光学元件,导致原有靶室结构的变化,可能会引入新的不稳定因素.通过有限元分析方法,建立有限元分析模型,进行优化设计.通过位移传感器测量结果可知,第九路终端光学元件径向窜动所引起的打靶误差最大值为2.110 μm,小于“神光-Ⅱ”靶场终端光学系统的最大允许误差值7.785 μm.

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千里光族是菊科中最大的一个族,约含有120属3400多种,全世界分布。千里光族的族下分类与系统发育一直是菊科研究中的难点。Jeffrey&Chen(1984)和千里光亚族(7属)。自此以后,有关东亚款冬亚族的范畴、亚族内各属的系统位置与亲缘关系就成了千里光族系统学研究中争论的焦点,至今仍未有定论。陈艺(1997)在东亚款冬亚族内发表假橐吾属新属。根据Jeffrey&Chen(1984)的概念,东亚款冬亚族现含13属。东亚款冬亚族目前存在的系统学问题主要有:(1)毛冠菊属是否与款冬亚族内的款冬属及蜂斗菜属近缘;(2)狗舌草亚族所辖3属是否是款冬亚族的自然成员;(3)东亚款冬亚族13属的系统位置及其亲缘关系;(4)东亚款冬亚族的影响范畴。 针对上述问题,本文以发现新的系统学证据为主要目的,较为全面地研究了东亚款冬亚族及其相关类群的外部形态学,首次报道了18属45种植物的花部微观性状,19属64种105个居群的核形态学特征,10属15种植物花粉壁的超薄结构及13属28种植物花粉的外壁纹饰,3种植物的胚胎发育和6种植物的ITS基因序列;并对所获得的证据进行了比较与综合分支分析。根据所获系统学资料,对东亚款冬亚族的上述系统学问题进行了讨论。主要实验结果及结论总结如下。 1. 外部形态 较为全面地观察与分析了东亚款冬亚族及其相关类群外部形态性状及其演化趋势,指出根状茎分枝方式、幼叶出土性状、花部茎基部叶是否宿存、叶柄是否纤维状宿存、花序托空心或实心、花药基部结构等不被以前作者重视或忽视的形态学性状可能具有重要的系统学价值。外部形态上,毛冠菊属与千里光族内的千里光属与款冬属等类群没有亲缘关系,而与紫菀族存在一定的渊源;狗舌草亚族则介于千里光亚族和款冬亚族之间;东亚款冬亚族13属可依据外部形态划分为6个属群。 2. 花部微观性状 东亚款冬亚族及其相关类群的花部微观性状主要包括:花药顶端不育组织、花药药室内壁、花药基部、花药领、花柱分枝顶端、花柱毛被、花柱分枝内表面构型、果柄细胞列数等。花部微观性状研究表明:毛冠菊属似乎应作为紫菀族中的一个孤立属;狗舌草亚族在某些衍征上与千里光亚族接近,而它的原始性状则类似于款冬亚族;根据花部微观性状对东亚款冬亚族的13个属划分出的自然属群与形态性状分析所得结果基本一致。 3. 核形态学 毛冠菊属的染色体基数为x=9,与紫菀族相同:而与千里光族和旋覆花族的染色体x=10存在显著的区别。狗舌草亚族中新发现2n=24、60、72三个染色体数目,亚族内染色体基数之间的演化关系不清楚,利用染色体基数来探讨狗舌草亚族所辖属的系统位置和属间关系仍还比较困难。东亚款冬亚族的染色体基数主要有x=30、29、28、27、26;款冬亚族中普遍存在的染色体基数x=30可能有3种来源;核型可分为2A、3A、2B三大类型,虽然三种类型之间的染色体基数(x=30)有可能是不同起源的,但从整个千里光族来看,3A、2B应是较进化的类型。根据核形态学特征,东亚款冬亚族可分为款冬型、蟹甲草型和大吴风草型三类。在蟹甲草型染色体进化支上,存在染色体的非整倍性下降趋势。东亚款冬亚族存在的种内多倍性可能与不同的生境有关。 4. 花粉学 通过对东亚款冬亚族及其相关类群的花粉壁超微结构与扫描电镜观察,发现花粉壁超微结构存在“千里光型”和“向日葵型”两种类型。扫描电镜下,花粉外壁均为刺状纹饰,但在刺的长短、刺部是否膨大、刺基膨大上的纹饰以及刺基之间的纹饰等方面存在差别。毛冠菊属的花粉性状组合支持将其置于紫菀族中。狗舌草亚族的花粉性状与款冬亚族的有些属相似。款冬亚族各属的花粉生状组合所划分的属群与形态学、核形态学等方面的研究结果较为一致。 5. 胚胎学 款冬、掌裂橐吾和珠毛蟹甲草共同拥有药壁发育双子叶型;绒毡层发育属“The Comos bipinnatus”型;成熟花粉为3细胞型;单珠被,薄珠心,倒生胚珠;具发育相似的珠被绒毡层:胚橐发育4孢子型等胚胎学特征,但它们在胚囊发育方式、反足细胞数目、发殖物候上还存在区别。三属代表植物的胚胎学研究支持将它们作为同一亚族的成员。 6. 分子数据 利用本研究测得的华千里光属4种、狗舌草属1种和大吴风草属的ITS-1和ITS-2基因序列,结合从Genbank中得出的千里光族5属8种植物得ITS序列,用PAUP软件进行分析。研究结果表明,染色体基数、花粉超微结构、叶型和叶脉等性状在ITS分支图上存在趋同进化;华千里光属和狗舌草属不是单系群。并讨论了一些分类群的亲缘关系。 7. 分支分析 选择东亚款冬亚族和狗舌草亚族各属的代表种作为终端代表类群进行分支分析;分支分析表明染色体基数、与头状花序有关的性状、叶型及叶脉等性状存在较多的平行与逆转进化,而根状茎分枝类型、花部微观性状以及花粉性状则表现出较大的一致性。根据分支结果,作者认为应建立包括狗舌草亚族在内的广义东亚款冬亚族。 8. 系统学 毛冠菊属的性状组合支持将其置于紫菀族,排除在千里光族之外。广义东亚款冬亚族可分为7个属群:蟹甲草属群(包括蟹甲草属,华蟹甲草属,小蟹甲草属,兔儿伞属,蟹甲木属)、毛柱菊属群(毛柱菊属)、橐吾属群(包括橐吾属,垂头菊属,假橐吾属)、狗舌草属群(狗舌草属,华千里光属,羽叶千里光属)、多榔菊属群(多榔菊属)、大吴风草属群(大吴风草属)、款冬属群(款冬属,蜂斗菜属)。总结与讨论了各属群的系统位置、亲缘关系与存在的分类学问题。描述了华千里光属1新种。

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稻属(Oryza L.)隶属于禾本科(Gramineae)Ehrhartoideae亚科的稻族(Oryzeae),包括两个栽培种(亚洲栽培稻O. sativa和非洲栽培稻O. glaberrima)和大约20多个野生种,广布于热带亚洲、非洲、大洋洲、中美洲和南美洲。药用野生稻复合体(O. officinalis complex)是稻属中最大、也是最复杂的一个复合体,共包括9个种,含有5种染色体组类型(B、C、BC、CD 和E)。作为栽培稻品质改良的重要基因库,药用野生稻复合体在稻属中具有重要的地位。但是,相似的形态和重叠的地理分布使部分物种的分类和鉴定一直较为困难;种内染色体组构成和倍性的不同更增加了分类鉴定的复杂性。这种情况阻碍了对这些野生稻遗传优势的有效利用。另外,由于物种间断分布和缺乏明确的二倍体亲本等原因,药用野生稻复合体内的异源多倍体起源一直存在争议。本文通过细胞核乙醇脱氢酶基因(Adh)和nrDNA的内转录间隔区(ITS)限制性片段长度多态性(RFLP)分析;叶绿体matK 基因、trnL 内含子和trnL-trnF 基因间隔区、核基因Adh和GPA1以及核糖体DNA ITS片段等序列比较的方法,对药用野生稻复合体中染色体组和物种的鉴定、种间系统发育关系,以及异源多倍体CCDD物种的起源和多倍体ITS的分子进化等进行了研究。主要研究结果如下: 1. 利用核Adh 基因限制性片段长度多态性,检测了来自国际水稻研究所基因库的64份药用野生稻复合体的样品。结果证明,所有O. rhizomatis样品都是含C染色体组的二倍体,所有O. minuta样品都是含BC 染色体组的四倍体。但是,种子库中鉴定为O. officinalis、O. punctata和O. eichingeri的样品中,同时都发现了含C染色体组的二倍体和含BC染色体组的四倍体。四倍体的O. officinalis只在印度分布,而且曾被描述为另一个种O. malampuzhaensis。 四倍体的O. punctata,也被一些学者称为O. schweinfurthiana,被发现和其二倍体一样分布广泛。值得注意的是,有两个曾被作为O. officinalis 四倍体的样品实际上是含有CD染色体组的物种O. latifolia。我们的结果增进了对国际水稻研究所种子库中部分野生稻样品染色体组构成的理解, 纠正了以往对药用野生稻复合体样品的错误鉴定,为今后进一步研究和利用这部分资源提供了种质编目的重要基础。 2. 对稻属中代表不同地理分布区的、含CD染色体组的11个样品(包括77个克隆)的ITS片段进行了测序。基于这些ITS序列的限制性片段长度多态性,提出一个快速而可靠的区分稻属CD 染色体组物种的方法。这个方法的具体步骤是:(1)利用通用引物扩增ITS 片段;(2)利用限制性内切酶FokI和/或DraⅢ消化PCR扩增产物;(3)用1%的琼脂糖胶电泳并根据消化产物的片段长度多态性来区分不同物种。 3. 利用包括两个叶绿体片段(matK和 trnL-trnF)、nrDNA内转录间隔区(ITS)和三个核基因(Adh1、Adh2和GPA1)的同源序列分析,探讨了药用野生稻复合体中二倍体物种和它们所代表的染色体组之间的系统发育关系。独立和合并的基因系统发育树都显示了一致的结果,即C染色体组和B染色体组的亲缘关系要比它们和E染色体组的近。三个含C染色体组的二倍体中,O. officinalis 和O. rhizomatis表现出较近的亲缘关系。值得注意的是,在O. eichingeri种内,尽管基于多基因的数据支持来自斯里兰卡的样品和来自非洲的样品聚成一个分支,但是较低的支持率表明, 两个地区的样品之间存在着较高的遗传分化。 4. 稻属中含CD染色体组的物种特产于拉丁美洲,包括O. alta、 O. grandiglumis 和O. latifolia。由于具有相同的染色体组类型、相似的形态特征和重叠的地理分布,这3个物种间的系统发育关系一直存在争论。另外,因为美洲大陆上没有含C和D染色体组的二倍体物种存在,对这些含CD染色体组物种的可能起源也有不同的假设被提出。使这个问题更具挑战性的是,尽管开展了世界范围的收集,至今仍没有找到含D 染色体组的二倍体物种。在本研究中,代表含C、CD和E染色体组以及含G染色体组的外类群共7个物种,共15份样品的2个叶绿体片段(matK和trnL-trnF)和3个核基因(Adh1,Adh2 和 GPA1)部分片段被测序。基于简约法、距离法和最大似然法的系统发育分析都充分支持含CD染色体组的物种起源于一次杂交事件的推论,并且显示,在物种形成时,含C染色体组的物种(O. officinalis 或O. rhizomatis 而非O. eichingeri)可能承担了母本,而含E染色体组的物种(O. australiensis)则可能承担了父本。另外,CCDD物种间非常一致的系统发育关系表明,非常大的分歧存在于 O. latifolia 和其它两个种(O. alta和O. grandiglumis)之间,这个结果倾向于将后两个种处理为同种或同种下不同分类群。 5. 基于178个克隆序列比较,探讨了ITS在稻属多倍体中的致同进化及其系统学意义。研究发现稻属异源四倍体的ITS存在不同形式的进化方式:首先,非洲BBCC四倍体O. eichingeri和O. punctata 的ITS片段同时保留了双亲拷贝,而且系统发育研究表明,二倍体的O. eichingeri和O. punctata 可能是这两个四倍体的直接祖先;其次,亚洲四倍体O. malampuzhaensis和O. minuta 的ITS仅定向保留母本ITS拷贝;另外,美洲CCDD四倍体的ITS序列发生了双向致同进化,即O. alta和O. grandiglumis的ITS位点一致化成C染色体组类型,而O. latifolia一致化成 D/E 染色体组类型。我们的研究进一步表明在利用ITS片段进行系统发育分析时,特别是涉及异源多倍体时必须慎重。 6. 利用栽培稻的微卫星引物,对含B/C染色体组的6个物种,157个体的SSR位点进行扩增。结果在这些亲缘关系稍远的野生稻中得到7个SSR位点,其中5个位点表现出多态性。比较BB、CC和BBCC物种SSR位点的每位点平均等位基因数A、多态位点百分率P和期望杂合度He ,3项指标发现,四倍体物种的遗传多样性,总体上要高于二倍体物种;二倍体物种内部,O. officnalis的遗传变异最大。另外,以遗传相关性为标准,讨论了B/C染色体组物种间的系统发育关系,同时推测了现存二倍体物种和4个BBCC四倍体物种的遗传关系。

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 为探讨抚仙湖水质的诱变性及诱变因素,用蚕豆根尖细胞微核检测法,检测抚仙湖水质的诱变性。用 高灵敏度的电感耦合氩等离子体发射光谱法( ICP2AES) 检测水体中5 种诱变性离子浓度。用GC/ MS(色相色谱/ 质谱) 联机检测水体中的有机化学污染物。结果表明:抚仙湖水质具有诱变性,且呈现水域性差异;水质的诱变性 非水体中诱变性离子所致;但与水体中有机化合物的种数有显著的相关性。