Complex networks constructed from irrational number sequences

In this paper, we construct (d, r) networks from sequences of different irrational numbers. In detail, segment an irrational number sequence of length M into groups of d digits which represent the nodes while two consecutive groups overlap by r digits (r = 0,1,...,d-1), and the undirected edges indicate the adjacency between two consecutive groups. (3, r) and (4, r) networks are respectively constructed from 14 different irrational numbers and their topological properties are examined. By observation, we find that network topologies change with different values of d, r and even sequence length M instead of the types of irrational numbers, although they share some similar features with traditional random graphs. We make a further investigation to explain these interesting phenomena and propose the identical-degree random graph model. The results presented in this paper provide some insight into distributions of irrational number digits that may help better understanding of the nature of irrational numbers.

Highly efficient and stable organic light-emitting diodes employing MoO3-doped perylene-3, 4, 9, 10-tetracarboxylic dianhydride as hole injection layer

We report highly efficient and stable organic light-emitting diodes (OLEDs) with MoO3-doped perylene-3, 4, 9, 10-tetracarboxylic dianhydride (PTCDA) as hole injection layer (HIL). A green OLED with structure of ITO/20 wt% MoO3: PTCDA/NPB/Alq(3)/LiF/Al shows a long lifetime of 1012 h at the initial luminance of 2000 cd/m(2), which is 1.3 times more stable than that of the device with MoO3 as HIL. The current efficiency of 4.7 cd/A and power efficiency of 3.7 lm/W at about 100 cd/m(2) have been obtained. The charge transfer complex between PTCDA and MoO3 plays a decisive role in improving the performance of OLEDs.

The design structure system - A method for managing the design of complex systems

Systems design involves the determination of interdependent variables. Thus the precedence ordering for the tasks of determining these variables involves circuits. Circuits require planning decisions abut how to iterate and where to use estimates. Conventional planning techniques, such as critical path, do not deal with these problems. Techniques are shown in this paper which acknowledge these circuits in the design of systems. These techniques can be used to develop an effective engineering plan, showing where estimates are to be used, how design iterations and reviews are handled, and how information flows during the design work.

Multiple energy transfers in rare earth complex-doped SiO2 spheres

Silica spheres doped with Eu(TTFA)(3) and/or Sm(TTFA)(3) were synthesized by using the modified Stober method. The transmission electron microscope image reveals that the hybrid spheres have smooth surfaces and an average diameter of about 210 nm. Fluorescence spectrometer was used to analyze the fluorescence properties of hybrid spheres. The results show that multiple energy transfer processes are simultaneously achieved in the same samples co-doped with Eu (TTFA)(3) and Sm(TTFA)(3), namely between the ligand and Eu3+ ion, the ligand and Sm3+ ion, and Sm3+ ion and Eu3+, ion. Energy transfer of Sm3+-> Eu3+, in the hybrid spheres leads to fluorescence enhancement of Eu3+ emission by approximately an order of magnitude. The lifetimes of the hybrid spheres were also measured.

Optical properties of a novel neodymium pentafluoropropionate binuclear complex

A novel neodymium pentafluoropropionate binuclear complex, Nd(C(2)F(5)COO)(3)Dipy (Dipy: 2,2'-dipyridyl), was synthesized and characterized by single-crystal X-ray diffraction. At a concentration of 0.2 M in DMSO-d(6), the Judd-Ofelt parameters (Omega(2), Omega(4), Omega(6)) were calculated from the UV-Vis spectrum. According to the small value of Omega(2) and the zero splitting energy of (4)F/(3/2) level, a symmetric ligand field of the complex was confirmed in DMSO-d(6). Strong emission of the complex in DMSO-d(6) at 1057 nm with a decay time about 1.3 mu s were detected when excited at 800 nm pumped by a laser diode. The stimulated emission cross-section of (4)F(3/2) -> (4)I(11/2) fluorescence transition was 2.36 x 10 (20) cm(2) and comparable with some laser glasses, which indicated good radiative properties of this neodymium pentafluoropropionate binuclear complex in liquid matrix. (c) 2008 Elsevier B.V. All rights reserved.

钠原子激光增强电离光谱研究—以石墨杯为原子化器 原子吸收光谱法对发样中Zn、Cu、Mn、Ap的测定

、I钠原子激光增强电离光谱(LEIS)方法的研究-以石墨杯为原子化器在LEIS方法中，最常见的原子化器是火焰。但由于火焰背景噪声严重且难以克服，在火焰原子化过程中，雾化和热离解不充分，仅有10~(-2)%的分析溶液参与吸收以及火焰气体使测定元素受到高度稀释等不利因素的影响，火焰原子化限制了LEIS方法灵敏度的进一步提高。考虑到石墨炉原子化器较火焰具有取样量少，绝对灵敏度高；样品（包括固态、液态）可直接引入石墨炉内；不会发生如同火焰中所存在的干扰效应；蒸发效率和原子化效率较高，几乎全部样品都能参与吸收等优点，本工作在已建立火焰LEIS方法的实验基础上，将原子化器改换为石墨杯进行了钠原子LEIS方法的研究。到目前为止，国内外仅有的几篇有关石黑炉LEIS的研究报告中，都报导了该方法对钠原子的检出限估计可达到10~(-14)-10~(-15)克，由于此项研究尚处于探索性研究阶段，故有关方法性的系统研究几乎还未见报导。本工作在未使用任何放大器的情况下（实验条件限制）对影响钠原子LEIS信号强度的诸因互进行了实验观察。主要包括：钠原子化条件；激光束位置、阳极电压、激光输出能量、电极位置以及激光脉冲重复率对LEIS信号强度的影响等。并绘制了校准曲线，统计方法的相对标准偏差分别为11%（高浓度）18.2%（低浓度），在现有仪器条件下，还不能测出检出限，测定下限为3*10~(-9)克。对固体粉末直接进行了尝试，检测下限为5*10~(-8)克，进样是为5毫克。在进一步的研究工作中，如有条件使用低噪声的放大器及Bxear积分器，选择门检时间窗，或采用分步激发等手段，估计本方法定会达到预想的高灵敏度，检敏度至少提高了个数量级。对石墨炉原子化LEIS法来说，似比较详细的研究报告，截至实验停止时还未见报导。II原子吸收光谱法对发样中Zn、Cu、Mn、Al的测定发中微量元素ZN、Cu、Mn均属人体必需元素，与人体的生长发育和多种生理功能，临床医学等方面有着极为密切的关系，而Al则被认为是异致某种疾病的元素之一。本工作报告了用火焰法测定Zn、Cu；石墨炉法测定Al、Mn的结果，其中，对Al的测定，为摆脱基体干扰，加入改进剂Mg(NO_3)_2，并采用平台石墨炉进行试验，得到了线性较好的工作曲线，但在实际测定时，由于实验条件的限制，只能采用一般石墨管加基体改进剂对少娄样品中Al含量进行测定。Zn、Cu、Al三种元素由标准曲线法测定；而Mn由于Fe的干扰无法消除而采用标准加入法测定，并因此限制了测定样品数。Cu、ZN、Mn三种元素的回收率分别为102.8%, 99.7%, 102.5%，变异系数为9.6%, 11.3%, 9.7%，对本地居民发中（30个发样）Zn、Cu含量进行测定，Zn、Cu的含量范围为148-318ppm，7.2-15ppm，并计算了Zn/Cu比。本方法对发样中四种元素的测定结果与ICP法进行对照。两种方法测定结果吻合得较好。

非洲爪蟾Nkx6.3在原肠运动和神经嵴诱导调控中的功能及爪蟾神经管腹侧图式形成的研究

神经嵴（neural crest）是一类脊椎动物特有的多潜能迁移细胞。这一类细胞历经“表皮—间充质”转换（EMT），与神经管背侧的其它细胞分离，经由不同路线迁移，定位于胚胎外周各处，后分化为不同的细胞类型包括外周神经系统、颅面骨骼系统及色素细胞等。神经嵴的发育是一个多途径多步骤的过程，受多种信号通路及转录因子调控。这些调控因子相互调节形成精密网络，可被划分为三个主要层次类群：分泌性信号分子（BMP、Wnt、FGF、Delta）、神经板边界特异基因（Msx、Pax3/7、 Zic1、Dlx3/5）、神经嵴特异基因（Snail/Slug、AP-2、FoxD3、Twist、Id、cMyc、Sox9/10）。本文第一章主要概述不同组织来源的各种分泌信号在神经嵴诱导中的作用以及他们之间的整合调控。 Nkx6家族蛋白是一类进化上保守的转录因子，在脊椎动物中枢神经系统（CNS)的图式形成和胰腺的发育中有重要作用。在第二章，我们描述了非洲爪蟾中Nkx6家族基因的克隆及其表达图式。与小鼠和鸡中的同源基因类似，爪蟾的Nkx6家族基因在胚胎发育过程中主要表达于中枢神经系统和前部内胚层组织。其中Nkx6.1和Nkx6.2在神经胚期神经板表达重合，晚期都表达于后脑和脊髓的腹侧。Nkx6.3从卵裂期到神经胚早期都表达于非神经外胚层，而尾芽期表达于后脑后部和腮弓。在内胚层中，Nkx6.2在尾芽期表达于底索。在蝌蚪期，Nkx6家族的三个基因分别表达于前部内胚层的衍生物，包括胰腺、胃、食道和肺。 Nkx6.3是最近发现的Nkx6家族新成员，它在爪蟾中的表达与Nkx6.1和Nkx6.2有了较大分歧。在第三章，我们通过功能获得及功能缺失实验来探讨Nkx6.3在爪蟾早期发育中的功能。我们发现原肠期前过量或抑制Nkx6.3表达都会影响胚胎原肠运动的正常进行。我们通过动物帽延伸实验证明Nkx6.3参与了细胞运动。半定量RT-PCR结果显示，Nkx6.3可以调控一些粘附分子的表达。以上结果说明Nkx6.3通过调控粘附分子的转录而参与细胞运动的调控。我们还发神经嵴（neural crest）是一类脊椎动物特有的多潜能迁移细胞。这一类细胞历经“表皮—间充质”转换（EMT），与神经管背侧的其它细胞分离，经由不同路线迁移，定位于胚胎外周各处，后分化为不同的细胞类型包括外周神经系统、颅面骨骼系统及色素细胞等。神经嵴的发育是一个多途径多步骤的过程，受多种信号通路及转录因子调控。这些调控因子相互调节形成精密网络，可被划分为三个主要层次类群：分泌性信号分子（BMP、Wnt、FGF、Delta）、神经板边界特异基因（Msx、Pax3/7、 Zic1、Dlx3/5）、神经嵴特异基因（Snail/Slug、AP-2、FoxD3、Twist、Id、cMyc、Sox9/10）。本文第一章主要概述不同组织来源的各种分泌信号在神经嵴诱导中的作用以及他们之间的整合调控。 Nkx6家族蛋白是一类进化上保守的转录因子，在脊椎动物中枢神经系统（CNS)的图式形成和胰腺的发育中有重要作用。在第二章，我们描述了非洲爪蟾中Nkx6家族基因的克隆及其表达图式。与小鼠和鸡中的同源基因类似，爪蟾的Nkx6家族基因在胚胎发育过程中主要表达于中枢神经系统和前部内胚层组织。其中Nkx6.1和Nkx6.2在神经胚期神经板表达重合，晚期都表达于后脑和脊髓的腹侧。Nkx6.3从卵裂期到神经胚早期都表达于非神经外胚层，而尾芽期表达于后脑后部和腮弓。在内胚层中，Nkx6.2在尾芽期表达于底索。在蝌蚪期，Nkx6家族的三个基因分别表达于前部内胚层的衍生物，包括胰腺、胃、食道和肺。 Nkx6.3是最近发现的Nkx6家族新成员，它在爪蟾中的表达与Nkx6.1和Nkx6.2有了较大分歧。在第三章，我们通过功能获得及功能缺失实验来探讨Nkx6.3在爪蟾早期发育中的功能。我们发现原肠期前过量或抑制Nkx6.3表达都会影响胚胎原肠运动的正常进行。我们通过动物帽延伸实验证明Nkx6.3参与了细胞运动。半定量RT-PCR结果显示，Nkx6.3可以调控一些粘附分子的表达。以上结果说明Nkx6.3通过调控粘附分子的转录而参与细胞运动的调控。我们还发现，在爪蟾胚胎中Nkx6.3的过表达或抑制表达都导致神经嵴标记基因表达降低。进一步研究发现，32细胞期在不同部位注射Nkx6.3 mRNA可以异位诱导或抑制Slug的表达。动物帽实验显示，Nkx6.3单独过表达可以诱导神经嵴发生，而迄今为止转录因子中只有Snail1具有这一单独诱导能力。在爪蟾胚胎及动物帽中，过表达Nkx6.3都可以诱导Fgf8、Wnt8而抑制BMP4的转录，而且Nkx6.3对这些分泌因子的调控方式是不同的。4细胞期过表达Nkx6.3的胚胎，在促进Fgf8和Wnt8而抑制BMP4的同时，却抑制神经板边界特异基因Msx1、Pax3和神经嵴特异基因Slug的表达，说明Nkx6.3对神经嵴的诱导调控在神经板边界基因层次还存在抑制作用。32细胞过表达Nkx6.3会细胞自主性抑制以及细胞非自主诱导Msx1、Pax3、Slug的表达。Nkx6.3异位诱导Dlx5却抑制Dlx3的表达，说明Dlx5可能是Nkx6.3负调控的直接靶基因。由此，我们提出Nkx6.3的神经嵴诱导调控分为两个层次：分泌信号分子水平的正调控和神经板边界决定水平的负调控。在脊椎动物的神经发生过程中，神经管背腹不同层次形成不同的神经元。这些神经元细胞的命运由背腹起源的多种形态发生素决定。形态发生素通过浓度梯度确定了一组转录因子在神经管背腹不同层次的特异表达，这些基因的组合调控决定了神经前体细胞的命运。然而，这些转录因子是如何解读形态发生素梯度信号的还不是很清楚。第四章，我们通过对神经管腹侧特异表达的转录因子的调控区进行预测，确定了可能调控这些基因表达的保守区段。此外，我们改进了爪蟾转基因操作，并用这一技术确证了Nkx6.2的调控区域。Dbx1、Nkx2.2及Pax6的转录调控区已在小鼠或爪蟾中报道过。由此我们得到了两对在神经管背腹图式中相互作用的转录因子的调控区域：Nkx6.2和Dbx1、Nkx2.2和Pax6。通过对Nkx6.2和Dbx1的调控保守区的转录因子结合位点的预测，我们发现这四个基因以及Wnt信号之间存在大量的相互调控。然而在这两个基因的调控区，我们没有发现Gli的调控位点，暗示这两个基因可能不受Shh的直接调控。我们还克隆了Dbx家族的两个基因，并检测了它们的时空特异性表达，发现Dbx2是母源性表达的，而Dbx1是合子型基因。这两个基因的表达图式相似，都在神经板中线两侧成线状表达，尾芽期在神经管中部表达。过表达Dbx2抑制神经元的初级分化，说明它可能与Dbx1一样具有维持神经板细胞未分化状态的功能。Dbx2的过表达还抑制Nkx6.2及Dbx1的表达，说明它们可能一起参与了神经管腹侧图式的调控。

Slow cross-symmetry phase relaxation in complex collisions

We discuss the effect of slow phase relaxation and the spin off-diagonal S-matrix correlations on the cross-section energy oscillations and the time evolution of the highly excited intermediate systems formed in complex collisions. Such deformed intermediate complexes with strongly overlapping resonances can be formed in heavy-ion collisions, bimolecular chemical reactions, and atomic cluster collisions. The effects of quasiperiodic energy dependence of the cross sections, coherent rotation of the hyperdeformed similar or equal to(3 : 1) intermediate complex, Schrodinger cat states, and quantum-classical transition are studied for Mg-24 + Si-28 heavy-ion scattering.

Double proton transfer and one-electron oxidation behaviors in double H-bonded glycinamide-formamidine complex and comparison with biological base pair

The behaviors of double proton transfer (DPT) occurring in a representative glycinamide-formamidine complex have been investigated employing the B3LYP/6-311++G** level of theory. Computational results suggest that the participation of a formamidine molecule favors the proceeding of the proton transfer (PT) for glycinamide compared with that without mediator-assisted case. The DPT process proceeds with a concerted mechanism rather than a stepwise one since no zwitterionic complexes have been located during the DPT process. The barrier heights are 14.4 and 3.9 kcal/mol for the forward and reverse directions, respectively. However, both of them have been reduced by 3.1 and 2.9 kcal/mol to 11.3 and 1.0 kcal/mol with further inclusion of zero-point vibrational energy (ZPVE) corrections, where the lower reverse barrier height implies that the reverse reaction should proceed easily at any temperature of biological importance. Additionally, the one-electron oxidation process for the double H-bonded glycinamide-formamidine complex has also been investigated. The oxidated product is characterized by a distonic radical cation due to the fact that one-electron oxidation takes place on glycinamide fragment and a proton has been transferred from glycinamide to formamidine fragment spontaneously. As a result, the vertical and adiabatic ionization potentials for the neutral double H-bonded complex have been determined to be about 8.46 and 7.73 eV, respectively, where both of them have been reduced by about 0.79 and 0.87 eV relative to those of isolated glycinamide due to the formation of the intermolecular H-bond with formamidine. Finally, the differences between model system and adenine-thymine base pair have been discussed briefly.

Molybdenum containing surface complex for olefin epoxidation

Silica-supported molybdenum surface complexes were prepared by the reaction between (N=) Mo(OtBu)(3) and silica via displacement of the tert-butoxy ligands for siloxyls from the silica surface. The structure of the surface molybdenum complexes was well defined by in-situ FT-IR, elemental analysis, H-1 NMR and C-13 CP/MAS NMR techniques. The surface complexes could undergo alcoholysis reaction with CD3OD and CH3OH in the same way as free (N =) Mo(OtBu)(3) and they show high catalytic activity and selectivity in olefin epoxidation. Initial rates up to 24.9 mmol epoxide (mmol Mo)(-1) min(-1) were achieved in the epoxidation of cyclohexene using TBHP as oxidant.

Photo-induced reactions in the ion-molecule complex Mg+-OCNC2H5

Ion - molecule complexes of magnesium cation with ethyl isocyanate were produced in a laser- ablation supersonic expansion nozzle source. Photo- induced reactions in the 1: 1 complexes have been studied in the spectral range of 230 - 410 nm. Photodissociation mass spectrometry revealed the persistent product Mg+ from nonreactive quenching throughout the entire wavelength range. As for the reactive channels, the photoproducts, Mg+OCN and C2H5+, were produced only in the blue absorption band of the complex with low yields. The action spectrum of Mg+(OCNC2H5) consists of two pronounced peaks on the red and blue sides of the Mg+ 3(2)P <-- 3(2)S atomic transition. The ground state geometry of Mg+ - OCNC2H5 was fully optimized at B3LYP/6- 31 - G** level by using GAUSSIAN 98 package. The calculated absorption spectrum of the complex using the optimized structure of its ground state agrees well with the observed action spectrum. Photofragment branching fractions of the products are almost independent of the photolysis photon energy for the 3P(x,y,z) excitations. The very low branching ratio of reactive products to nonreactive fragment suggests that evaporation is the main relaxation pathway in the photo- induced reactions of Mg+ (OCNC2H5). (C) 2003 American Institute of Physics.

Profiling of Complex Microbial Populations by Denaturing Gradient Gel Electrophoresis Analysis of Polymerase Chain Reaction-Amplified Genes Coding for 16S rRNA

We describe a new molecular approach to analyzing the genetic diversity of complex microbial populations. This technique is based on the separation of polymerase chain reaction-amplified fragments of genes coding for 16S rRNA, all the same length, by denaturing gradient gel electrophoresis (DGGE). DGGE analysis of different microbial communities demonstrated the presence of up to 10 distinguishable bands in the separation pattern, which were most likely derived from as many different species constituting these populations, and thereby generated a DGGE profile of the populations. We showed that it is possible to identify constituents which represent only 1% of the total population. With an oligonucleotide probe specific for the V3 region of 16S rRNA of sulfate-reducing bacteria, particular DNA fragments from some of the microbial populations could be identified by hybridization analysis. Analysis of the genomic DNA from a bacterial biofilm grown under aerobic conditions suggests that sulfate-reducing bacteria, despite their anaerobicity, were present in this environment. The results we obtained demonstrate that this technique will contribute to our understanding of the genetic diversity of uncharacterized microbial populations.

Spatial variability in water quality and surface sediment diatom assemblages in a complex lake basin,lake of the woods,ontario,canada

Lake of the Woods (LOW) is an international waterbody spanning the Canadian provinces of Ontario and Manitoba, and the U.S. state of Minnesota. In recent years, there has been a perception that water quality has deteriorated in northern regions of the lake, with all increase in the frequency and intensity of toxin-producing cyanobacterial blooms. However, given the lack of long-term data these trends are difficult to verify. As a first step, we examine spatial and seasonal patterns in water quality in this highly complex lake on the Canadian Shield. Further, we examine surface sediment diatom assemblages across multiple sites to determine if they track within-take differences in environmental conditions. Our results show that there are significant spatial patterns in water quality in LOW. Principal Component Analysis divides the lake into three geographic zones based primarily on algal nutrients (i.e., total phosphorus, TP), with the highest concentrations at sites proximal to Rainy River. This variation is closely tracked by sedimentary diatom assemblages, with [TP] explaining 43% of the variation in diatom assemblages across sites. The close correlation between water quality and the surface sediment diatom record indicate that paleoecological models could be used to provide data on the relative importance of natural and anthropogenic sources of nutrients to the lake.