Surface-enhanced Raman scattering of 4-aminothiophenol self-assembled monolayers in sandwich structure with nanoparticle shape dependence: Off-surface plasmon resonance condition

A universal metal-molecule-metal sandwich architecture by the self-assembly of Ag nanoparticles (NPs) and Au NPs of various shapes interconnected with 4-aminothiophenol (4-ATP) molecules was presented. These Ag NPs/4-ATP/Au NPs sandwich structures were characterized by surface enhanced Raman scattering (SERS) using an off-surface plasmon resonance condition. Enhancement factors (EF) on the order of 10(8) for 9b(b(2)) vibration mode were observed for the 4-ATP self-assembled monolayers (SAMs) in such sandwich structures. The factors are 2 orders of magnitude larger than that on the monolayer of Au NPs of various shapes under similar condition. More importantly, remarkable increase in the intensity of b(2) vibrational modes, which is characteristic of the charge transfer (CT) behavior between metal NPs and 4-ATP molecules, was observed in these sandwich structures under 1064 nm excitation. The obtained EF on these sandwich structure for 9b(b(2)) is larger than that for 7a vibration mode by a factor of similar to 10(2), demonstrating the importance of the contribution of the CT mechanism and the CT behavior of metal contacts, which play a significant role in metal-molecule-metal nanosystems.

Controlled synthesis of nanoporous Au microsheet via surfactant emulsion template

A facile and wet-chemical approach was employed to control synthesis of self-organizing, hyperbranched nanoporous Au microsheet with high quality in bulk quantity. This method produced nanoporous Au microsheets with a thickness of 7-15 nm. The microsheets were composed of irregularly interconnected planar Au nanoplates with interstices, i.e. nanopores of 10-50 nm. And the nanoporous Au microsheets were enveloped in 10-30 nm thick polyaniline (PANI) sheaths. The morphology of the nanostructured Au composites could also be easily tuned by changing the concentration of aniline and chlorauric acid. The dendritic and epitaxial growth of nanoporous Au microsheet was believed as the diffusion-limited process confined in the lamellar emulsion phase through self-assembly of aniline and dodecylsulfate. The solution reaction proceeded at a mild condition (room temperature and aqueous solutions), and less toxic reagents were employed instead of extreme toxic and corrosive chemicals.

Spontaneous formation of two-dimensional gold networks at the air-water interface and their application in surface-enhanced Raman scattering (SERS)

Two-dimensional (2-D) gold networks were spontaneously formed at the air-water interface after HAuCl4 reacted with fructose at 90 degrees C in a sealed vessel, in a reaction in which fructose acted as both a reducing and a protecting agent. Through fine-tuning of the molar ratio of HAuCl4 to fructose, the thus-formed 2-D gold networks can be changed from a coalesced pattern to an interconnected pattern. In the coalesced pattern, some well-defined single-crystalline gold plates at the micrometer-scale could be seen, while in the interconnected pattern, many sub-micrometer particles and some irregular gold plates instead of well-defined gold plates appeared. It is also found that the 2-D gold networks in the form of an interconnected pattern can be used as substrates for surface-enhanced Raman scattering (SERS) because of the strong localized electromagnetic field produced by the gaps between the neighboring particles in the 2-D gold networks.

Syntheses and crystal structures of [Mn(H2O)(4)(bpy)]L center dot 4H(2)O, [Mn(H2O)(4)(bpy)]L ' center dot 4H(2)O (H2L = SUCCINIC ACID, H2L ' = FUMARIC ACID)

Reactions of freshly prepared M(OH)(2-2x)(CO3)(x) (.) yH(2)O (M = Mn, Zn) and 4,4'-bipyridine (bpy) with succinic acid (H2L) or famaric acid (H2L') in CH3OH-H2O afforded [Mn(H2O)(4)(bpy)]L (.) 4H(2)O, 1, [Mn(H2O)(4)(bpy)]L' (.) 4H(2)O, 2 and [Zn(H2O)(4)(bpy)]L (.) 4H(2)O, 3. The three coordination polymers are isostructural and consist of (1)(infinity)[M(H2O)(4)(bpy)(2/2)](2+) cationic chains, crystal H2O molecules and dicarboxylate anions (succinate or fumarate anions). Within the chains, the metal atoms are each octahedrally coordinated by four aqua oxygen atoms and two pyridyl nitrogen atoms from two 4,4'-bipyridine ligands. The crystal H2O molecules are hydrogen bonded to dicarboxylate anions to form ribbon-like anionic chains. The cationic and anionic chains are interconnected via hyqrogen bonds to generate a 3D network. Crystal data: 1 triclinic, P (1) over bar, a = 7.235(1), b = 7.749(2), c = 10.020(2) Angstrom, alpha = 79.95(3), beta = 88.79(3), gamma = 71.39(3)degrees, V = 523.9(2) Angstrom(3) and D-cal = 1.494 g cm(-3) for Z = 1; 2 triclinic, P (1) over bar, a = 7.127(1), b = 7.800(2), c = 9.945(2) Angstrom, alpha = 80.26(3), beta = 87.86(3), gamma = 72.69(3)degrees, V = 520.2(2) Angstrom(3) and D-cal = 1.498 g cm(-3) for Z = 1; 3 triclinic, P (1) over bar, a = 7.189(1), b = 7.764(2), c = 9.843(2) Angstrom, alpha = 79.16(3), beta = 87.80(3), gamma = 71.29(3)degrees, V = 510.9(2) Angstrom(3) and D-cal = 1.559 g cm(-3) for Z = 1.

Viscous-force-dominated tensile deformation behavior of oriented polyethylene

High-density polyethylene with shish-kebab structure, prepared by a melt extrusion drawing, was employed to investigate the effect of the well-defined lamellar orientation on the deformation characteristics under uniaxial tensile deformation along the drawing direction. This was done by investigating the true stress-true strain dependencies at different strain rates, recovery properties, and stress relaxation measurements. Measurements were complemented by recording in-situ wide-angle X-ray scattering patterns during the deformation process. The oriented samples showed not only a higher modulus, but different from analogous isotropic samples, a homogeneous deformation without necking. The true strain associated with the onset of fibrillation was determined. Because of the preorientation, it is shifted to 0.3, which is below the value 0.6 of the isotropic counterpart. The main finding is a strong enhancement of the Viscous force, as was revealed by stress relaxation experiments; the viscous force takes up 70% of the total stress. The presence of shish-kebabs, i.e., interconnected lamellae in a stack, seems to be responsible for the high viscous force in the oriented samples. The absence of necking has to be ascribed to the high viscous force.

Hydrothermal growth and gas sensing property of flower-shaped SnS2 nanostructures

Unusual 3D flower-shaped SnS2 nanostructures have been synthesized using a mild hydrothermal treatment in the presence of octyl-phenol-ethoxylate ( Triton X-100) at 160 degrees C. The nanostructures have an average size of 1 mu m, and consist of interconnected nanosheets with thicknesses of about 40 nm. Based on time-dependent experimental results, we ascribe the oriented attachment mechanism to the growth of the SnS2 nanostructures. The nonionic surfactant Triton X-100 plays a key role in the formation of the flower-like morphology. Room temperature gas-sensing measurements show that the 3D SnS2 nanostructures could serve as sensor materials for the detection of NH3 molecules.

Sol-gel-derived ceramic carbon composite electrode containing isopolymolybdic anions

A new class of polyoxomelalate (POM)-modified electrodes is fabricated by the sol-gel technique and demonstrated for nitrite sensing. The electrode material comprises an interconnected dispersion of graphite powder and a uniform dispersion of isopolymolybdic anions (Mo8O26) in a porous methylsilicate matrix. The chemically modified electrodes showed well-defined cyclic voltammograms with three reversible redox couples in acidic aqueous solutions because of the good physicochemical compatibility of Mo8O26 and the carbon ceramic matrix. The Mo8O26-modified electrodes show good stability and reproducibility, especially the renewal repeatability by simple polishing in the event of surface fouling. (C) 2000 Elsevier Science Ltd. All rights reserved.

Nanocluster-containing mesoporous magnetoceramics from hyperbranched organometallic polymer precursors

Pyrolysis of hyperbranched poly[1,1'-ferrocenylene(methyl)silyne] (5) yields mesoporous, conductive, and magnetic ceramics (6). Sintering at high temperatures (1000-1200 degrees C) under nitrogen and argon converts 5 to 6N and 6A, respectively, in similar to 48-62% yields. The ceramization yields of 5 are higher than that (similar to 36%) of its linear counterpart poly[1,1'-ferrocenylene(dimethyl)silylene] (1), revealing that the hyperbranched polymer is superior to the linear one as a ceramic precursor. The ceramic products 6 are characterized by SEM, XPS, EDX, XRD, and SQUID. It is found that the ceramics are electrically conductive and possess a mesoporous architecture constructed of tortuously interconnected nanoclusters. The iron contents of 6 estimated by EDX are 36-43%, much higher than that (11%) of the ceramic 2 prepared from the linear precursor 1. The nanocrystals in 6N are mainly alpha-Fe2O3 whereas those in 6A are mainly Fe3Si. When magnetized by an external field at room temperature, 6A exhibits a high-saturation magnetization (M-s similar to 49 emu/g) and near-zero remanence and coercivity; that is, 6A is an excellent soft ferromagnetic material with an extremely low hysteresis loss.

Unprecedented 5,5-connected (4(7)center dot 6(3)) (4(8)center dot 6(2)) structural topology: A lead biphosphonate with double layered structure

A new lead(II) phosphonate, Pb[(PO3)(2)C(OH)CH3]center dot H2O (1) was hydrothermally synthesized and characterized by IR, elemental analysis, UV, TGA, SEM, and single crystal X-ray diffraction analysis. X-ray crystallographic study showed that complex 1 has a two-dimensional double layered hybrid structure containing interconnected 4- and 12-membered rings and shows an unusual (5,5)-connected (4(7) . 6(3)) (4(8) .6(2)) topology. (C) 2008 Elsevier B.V. All rights reserved.

机器人多级自适应控制器鲁棒性分析

本文给出了机器人关节系统多级自适应控制器的鲁棒性分析.分析表明机器人多级自适应控制系统即使子系统间存在相互关联项和子系统存在未建模特性.采用σ-修正法也能保证系统的输出有界.

基于CAN总线的分布式数据采集与控制系统

随着电子技术和计算机技术的不断发展，工业生产过程的控制系统正在向着智能化、数字化和网络化的方向发展。传统的集散控制方式和计算机分层控制方式已经开始让位于智能终端与网络结合的总线网络控制方式。当今，在工厂中过程控制环境下的分布式自动化系统变得越来越复杂，尤其系统内部的各设备之间需要快速交换大量的信息，以便实现对被控系统更为精确的控制和提供一些辅助的评价函数。这就意味着要不断增加带宽和提高通信速率以满足网络通信的需要。在现有的多种可利用网络设备中，CAN总线以其清晰的定义、极高的可靠性及其独特的设计，被认为是最能有效地解决这一问题的途径之一。而且市场上基于通信技术的产品中，就实时性考虑，由于CAN总线采用的非表意性的通信方式，因此其结构更为简单，实时性更好。基于此背景，我们以CAN总线作为通信媒介，将分布于各控制现场的传感器、执行器和控制器有序地连接起来，构成了一个基于CAN总线的分布式局域网络控制系统。本文首先介绍了基于CAN总线的分布式数据采集与控制系统的总体结构。然后从硬件方面描述了基于CAN总线的通信协议转换单元、数据采集单元和输出控制单元的功能、硬件配置及各单元功能的具体实现过程，给出了各单元的性能指标。软件方面，以C语言作为平台，开发了基于CAN总线的上位计算机管理与监控软件，实现了对整个网络设备的系统管理和系统控制功能。对于该总线系统，作者运用了PID控制和模糊控制算法实现了对水箱液位的控制，达到了理想的效果。基于CAN总线的控制系统很好地解决了集散控制系统难以解决的难题，模糊控制的应用能很好地把总线控制系统应用到具有非线性、大时滞和难于获得精确模型的控制系统中。

陡坡带砂砾岩体油气成藏模式研究——以东营凹陷西北部陡坡带为例

Based on the study of sequence stratigraphy, modern sedimentary, basin analysis, and petroleum system in abrupt slop of depression, this paper builds sedimentary system and model, sandy bodies distribution, and pool-forming mechanism of subtle trap. There are some conclusions and views as follows. By a lot of well logging and seismic analysis, the author founded up the sequence stratigraphic of the abrupt slope, systematically illustrated the abrupt slope constructive framework, and pointed out that there was a special characteristics which was that south-north could be divided to several fault block and east-west could be carved up groove and the bridge in studying area. Based all these, the author divided the studying area to 3 fault block zone in which because of the groove became the basement rock channel down which ancient rivers breathed into the lake, the alluvial fan or fan delta were formed. In the paper, the author illustrated the depositional system and depositional model of abrupt slope zone, and distinguished 16 kinds of lithofacies and 3 kinds of depositional systems which were the alluvial fan and fan-delta system, lake system and the turbidite fan or turbidity current deposition. It is first time to expound completely the genetic pattern and distributing rule of the abrupt slope sandy-conglomeratic fan bodies. The abrupt slope sandy-conglomeratic fan bodies distribute around the heaves showing itself circularity shape. In studying area, the sandy-conglomeratic fan bodies mainly distribute up the southern slope of Binxian heave and Chenjiazhuang heave. There mainly are these sandy-conglomeratic fan body colony which distributes at a wide rage including the alluvial fan, sub-water fluvial and the turbidite fan or the other turbidity current deposition in the I fault block of the Wangzhuang area. In the II fault block there are fan-delta front and sub-water fluvial. And in the Binnan area, there mainly are those the alluvial fan (down the basement rock channel) and the sandy-conglomeratic fan body which formed as narrowband sub-water fluvial (the position of bridge of a nose) in the I fault block, the fan-delta front sandy-conglomeratic fan body in the H fault block and the fan-delta front and the turbidity current deposition sandy-conglomeratic fan body in the m fault block. Based on the reservoir outstanding characteristics of complex classic composition and the low texture maturity, the author comparted the reservoir micro-structure of the Sha-III and Sha-IV member to 4 types including the viscous crude cementation type, the pad cementation type, the calcite pore-funds type and the complex filling type, and hereby synthetically evaluated 4 types sandy- conglomeratic fan body reservoir. In the west-north abrupt slope zone of Dongying Depression, the crude oil source is belonging to the Sha-III and Sha-IV member, the deep oil of Lijin oilfield respectively come from the Sha-III and Sha-IV member, which belongs to the autogeny and original deposition type; and the more crude oil producing by Sha-IV member was migrated to the Wangzhuan area and Zhengjia area. The crude oil of Binnan oil-field and Shanjiasi oil-field belongs to mixed genetic. It is the first time to illustrate systematically the genetic of the viscous crude that largely being in the studying area, which are that the dissipation of the light component after pool-forming, the biological gradation action and the bath-oxidation action, these oil accumulation belonging to the secondary viscous crude accumulation. It is also the first time to compart the studying area to 5 pool-forming dynamical system that have the characteristic including the common pressure and abnormal pressure system, the self-fountain and other-fountain system and the closing and half-closing system etc. The 5 dynamical systems reciprocally interconnected via the disappearance or merger of the Ethology and the fluid pressure compartment zone, the fault and the unconformity surface, hereby formed duplicated pattern oil-gas collecting zone. Three oil-gas pool-forming pattern were founded, which included the self-fountain side-direction migrated collecting pattern, the self-fountain side-direction ladder-shape pool-forming pattern and the other-fountain pressure releasing zone migrated collecting pattern. A series of systemic sandy-conglomeratic fan bodies oil-gas predicting theory and method was founded, based on the groove-fan corresponding relation to confirm the favorable aim area, according as the characteristic of seismic-facies to identify qualitatively the sandy-conglomeratic fan bodies or its scale, used the temporal and frequency analysis technique to score the interior structure of the sandy- conglomeratic fan bodies, applied for coherent-data system analysis technology to describe the boundary of the sandy-conglomeratic fan bodies, and utilized the well logging restriction inversion technique to trace quantificational and forecast the sandy-conglomeratic fan bodies. Applied this technique, totally 15 beneficial sandy-conglomeratic fan bodies were predicted, in studying area the exploration was preferably guided, and the larger economic benefit and social benefit was acquired.