Large Scale Fabrication Of Periodical Bowl-Like Micropatterns Of Single Crystal Zno

Nanostructured ZnO materials are of great significance for their potential applications in photoelectronic devices, light-emitting displays, catalysis and gas sensors. In this paper, we report a new method to produce large area periodical bowl-like micropatterns of single crystal ZnO through aqueous-phase epitaxial growth on a ZnO single crystal substrate. A self-assembled monolayer of polystyrene microspheres was used as a template to confine the epitaxial growth of single crystal ZnO from the substrate, while the growth morphology was well controlled by citrate anions. Moreover, it was found that the self-assembled monolayer of colloidal spheres plays an important role in reduction of the defect density in the epitaxial ZnO layer. Though the mechanism is still open for further investigation, the present result indicates a new route to suppress the dislocations in the fabrication of single crystal ZnO film. A predicable application of this new method is for the fabrication of two-dimensional photonic crystal structures on light emitting diode surfaces.

Guiding and confining fast electrons by transient electric and magnetic fields with a plasma inverse cone

The fast electron propagation in an inverse cone target is investigated computationally and experimentally. Two-dimensional particle-in-cell simulation shows that fast electrons with substantial numbers are generated at the outer tip of an inverse cone target irradiated by a short intense laser pulse. These electrons are guided and confined to propagate along the inverse cone wall, forming a large surface current. The propagation induces strong transient electric and magnetic fields which guide and confine the surface electron current. The experiment qualitatively verifies the guiding and confinement of the strong electron current in the wall surface. The large surface current and induced strong fields are of importance for fast ignition related researches.

高功率激光装置前端系统激光脉冲的时间整形及修正技术

针对激光惯性约束聚变实验研究对高功率激光驱动器前端系统复杂时间形状种子激光脉冲的需求, 应用孔径耦合带状线集成波导整形系统设计了满足需要的前端整形激光脉冲。用一种新方法精确计算了孔径耦合带状线电脉冲整形器的耦合系数和孔径宽度的数值关系, 并针对高衬比度整形激光脉冲的需求, 提出了高衬比度双极型集成波导整形系统方案。由该系统可以得到100 ps脉冲前沿、1～3 ns脉冲宽度可调、高衬比度(大于100∶1)、光滑无纹波调制、可精确满足神光II八路及第九路装置需求的前端整形激光脉冲。

锥形光纤的功率分布特性

从波动理论出发,对锥形光纤的纵向传播常数进行泰勒(Taylor)级数展开,经近似得到了锥形光纤功率分布的解。基于此理论,对锥形光纤的功率分布特性进行了讨论,并分析了锥形光纤的长度、锥度和光纤折射率等参数对锥形光纤不同模式功率分布的影响。为了减小功率泄漏,当光从锥形光纤大端入射时,应当减小锥长,减小锥度,增大纤芯包层折射率差;当光从锥形光纤小端入射时,应当增加锥长,增加锥度,增大纤芯包层折射率差。在长锥长、大锥度情况下,光纤折射率分布的影响相对较小。

Numerical study of sub-wavelength plasmonic waveguide

The authors present an analysis of a plasmonic waveguide, simulated using a two-dimensional finite-difference time-domain technique. With the surface structures located on the surface of the metal, the device is able to confine and guide light waves in a sub-wavelength scale. And two waveguides can be placed within 150 nm (similar to 6% of the incident wavelength) that will helpful for the optoelectronic integration. Within the 20 mu m simulation region, it is found that the intensity of the guided light at the interface is roughly two to four times the peak intensity of the incident light, and the propagation length can reach approximately 40 Pm at the wavelength of 2.44 mu m. (c) 2007 Elsevier B.V. All rights reserved.

Resonant Enhanced Wave Filter and Waveguide via Surface Plasmons

The authors present an analysis of plasmonic wave filter and curved waveguide, simulated using a 2-D finite-difference time-domain technique. With different dielectric materials or surface structures located on the interface of the metal/dielectric, the resonant enhanced wave filter can divide light waves of different wavelengths and guide them with low losses. And the straight or curved waveguide can confine and guide light waves in a subwavelength scale. Within the 20 mu m simulation region, it is found that the intensity of the guided light at the interface is roughly four times the peak intensity of the incident light.

p-type doping of GaInNAs quaternary alloys

Using the first-principles band-structure method, we investigate the p-type doping properties and band structural parameters of the random Ga1-xInxN1-yAsy quaternary alloys. We show that the Mg-Ga substitution is a better choice than ZnGa to realize the p-type doping because of the lower transition energy level and lower formation energy. The natural valence band alignment of GaAs and GaInNAs alloys is also calculated, and we find that the valence band maximum becomes higher with the increasing in composition. Therefore, we can tailor the band offset as desired which is helpful to confine the electrons effectively in optoelectronic devices. (C) 2008 Published by Elsevier B.V.

Plasmonic surface-wave splitter

The authors present an analysis of a plasmonic surface-wave splitter, simulated using a two-dimensional finite-difference time-domain technique. A single subwavelength slit is employed as a high-intensity nanoscale excitation source for plasmonic surface waves, resulting in a miniaturized light-surface plasmon coupler. With different surface structures located on the two sides of the slit, the device is able to confine and guide light waves of different wavelengths in opposite directions. Within the 15 mu m simulation region, it is found that the intensity of the guided light at the interface is roughly two to eight times the peak intensity of the incident light, and the propagation length can reach approximately 42 and 16 mu m and at the wavelengths of 0.63 and 1.33 mu m, respectively. (c) 2007 American Institute of Physics.

A new method to fabricate InGaN quantum dots by metalorganic chemical vapor deposition

A new method to form nanoscale InGaN quantum dots using MOCVD is reported, This method is much different from a method. which uses surfactant or the Stranski-Krastannow growth mode. The dots were formed by increasing the energy barrier for adatoms, which are hopping by surface passivation, and by decreasing the growth temperature. Thus, the new method can be called as a passivation-low-temperature method. Regular high-temperature GaN films were grown first and were passivated. A low-temperature thin layer of GaN dot was then deposited on the surface that acted as the adjusting layer. At last the high-density InGaN dots could be fabricated on the adjusting layer. Atomic force microscopy measurement revealed that InGaN dots were small enough to expect zero-dimensional quantum effects: The islands were typically 80 nm wide and 5 nm high. Their density was about 6 x 10(10) cm(-2). Strong photoluminescence emission from the dots is observed at room temperature, which is much stronger than that of the homogeneous InGaN film with the same growth time. Furthermore, the PL emission of the GaN adjusting layer shows 21 meV blueshift compared with the band edge emission of the GaN due to quantum confine effect. (C) 2002 Elsevier Science B.V. All rights reserved.

Stable Temperature Characteristics of InAs/GaAs Quantum Dots at Long Wavelength Emission

The time-resolved photoluminescence and steady photoluminescence (TRPL and PL) spectra on self-assembled InAs/GaAs quantum dots (QDs) are investigated. By depositing GaAs/InAs short period superlattices (SLs), 1. 48 μtm emission is obtained at room temperature. Temperature dependent PL measurements show that the PL intensity of the emission is very steady. It decays only to half as the temperature increases from 15 K to room temperature, while at the same time, the intensity of the other emission decreases by a factor of 5 orders of magnitude. These two emissions are attributed to large-size QDs and short period superlattices (SLs), respectively. Large-size QDs are easier to capture and confine carriers,which benefits the lifetime of PL, and therefore makes the emission intensity insensitive to the temperature.

Formation of low surface energy separators with undercut structures via a full-solution process and its application in inkjet printed matrix of polymer light-emitting diodes

In this paper, low surface energy separators With undercut structures were fabricated through a full solution process, These low Surface energy separators are more suitable for application in inkjet printed passive-matrix displays of polymer light-emitting diodes. A patterned PS film was formed on the P4VP/photoresist film by microtransfer printing firstly. Patterned Au-coated Ni film was formed on the uncovered P4VP/photoresist film by electroless deposition. This metal film was used as mask to pattern the photoresist layer and form undercut structures with the patterned photoresist layer. The surface energy of the metal film also decreased dramatically from 84.6 mj/m(2) to 21.1 mJ/m(2) by modification of fluorinated mercaptan self-assemble monolayer on Au surface. The low surface energy separators were used to confine the flow of inkjet printed PFO solution and improve the patterning resolution of inkjet printing successfully. Separated PFO stripes, complement with the pattern of the separators, formed through inkjet printing.

High PL quantum efficiency of poly(phenylene vinylene) systems through exciton confinement

Photoluminescence (PL) quantum efficiency is a key issue in designing successful light-emitting polymer systems. Exciton relaxation is strongly affected by exciton quenching at nonradiative trapping centers and the formation of excimers. These factors reduce the PL quantum yield of light-emitting polymers. In this work, we have systematically investigated the effects of exciton confinement on the PL quantum yield of an oligomer, polymer, and alternating block copolymer (ABC) PPV system. Time-resolved and temperature-dependent luminescence studies have been performed. The ABC design effectively confine photoexcitations within the chromophores, preventing exciton migration and excimer formation. An unusually high (PL) quantum yield (above 90%) in the solid state is reported for the alternating block copolymer PPV, as compared to that of similar to 30% of the polymer and oligomer model compounds. (C) 2000 Elsevier Science S.A. All rights reserved.

地震资料叠前储层预测综合研究--以辽中凹陷东二下段浊积扇气藏为例

Reservoir prediction techniques from prestack seismic are among the most important ones for exploration of lithologic hydrocarbon reservoir. In this paper, we set the turbidite fan sandstone reservoir in Liao-Zhong depress as our researching target, and aims to solve the apllication difficulties on pre-stack inversion in the area, where the drilling data is scarce and the reservoir is lateral varied. Meanwhile, AVO analysis and pre-stack inversion for gas-bearing detection is systematically researched. The seismic reflection characters of gas-bearing sandstone in turbidite fan with different fluid content are defined, after analyzing results from AVO seismic simulation and porous fluid replacement of real log data, and under the guides of the seismic characters from classical gas-bearing sandstone reservoir and numerical simulation for complicate gas-bearing sandstone. It is confirmed that detecting gas-bearing sandstone in turbidite fan via AVO technologies is feasible. In terms of AVO analysis, two AVO characters, fluid detection factor and product of intercept and gradient, can effectively identify top and bottom boundaries and lateral range of tuibidite gas sand by comparing real drilling data. Cross-plotting of near and far angle stack data could avoid the correlation existing in P-G analysis. After comparing the acoustic impedance inversions with routine stacked data and AVO intercept, impedance derived from AVO intercept attribute could reduce the acoustic impedance estimating error which is caused by AVO. On the aspect of elastic impedance inversion, the AVO information in the pre-stack gathers is properly reserved by creating partial angle stack data. By the far angle elastic impedance alone, the gas sand, with abnormally low range of values, can be identified from the background rocks. The boundary of gas sand can also be clearly determined by cross-plotting of near and far angle elastic impedances. The accuracy of far angle elastic impedance is very sensitive to the parameter K, and by taking the statistical average of Vp/Vs on the targeted section in key wells, the accuracy of low frequency trends is gurranteed; the intensive absorsion within the area of the gas sand, which tends to push the spectral of seismic data to the lower end, will cause errors on the inversion result of elastic impedance. The solution is to confine the inversion on the interested area by improving the wavelet. On the aspect of prestack AVA simultaneous inversion, the constraint of local rock-physical trends between velocities of P-wave、S-wave and density successfully removes the instability of inversion, thus improves the precision of the resulting elastic parameters. Plenty of data on rock properties are derived via AVO analysis and prestack seismic data inversion. Based on them, the fluid anomaly is analysized and lithological interpretation are conducted. The distribution of gas sand can be consistently determined via various of ways, such as cross-plotting of P and G attributes, near and far partial angle stack data, near and far angle elastic impedances, λρ and Vp/Vs, etc. The shear modulo and density are also reliable enough to be used for lithological interpretation. We successfully applied the AVO analysis and pre-stack inversion techniques to gas detecting for turbidite fan sand reservoir in Liao-Zhong depression.

中国大中型气田天然气成藏物理化学模拟研究

Natural gas pays more important role in the society as clean fuel. Natural gas exploration has been enhanced in recent years in many countries. It also has prospective future in our country through "85" and "95" national research. Many big size gas fields have been discovered in different formations in different basins such as lower and upper Paleozoic in Erdos basin, Tertiary system in Kuche depression in Tarim basin, Triassic system in east of Sichuan basin. Because gas bearing basins had been experienced multiple tectogenesis. The characteristics of natural gases usually in one gas field are that they have multiple source rocks and are multiple maturities and formed in different ages. There has most difficult to research on the gas-rock correlation and mechanism of gas formation. Develop advanced techniques and methods and apply them to solve above problems is necessary. The research is focused on the critical techniques of geochemistry and physical simulation of gas-rock correlation and gas formation. The lists in the following are conclusions through research and lots of experiments. I 8 advanced techniques have been developed or improved about gas-rock correlation and gas migration, accumulation and formation. A series of geochemistry techniques has been developed about analyzing inclusion enclave. They are analyzing gas and liquid composition and biomarker and on-line individual carbon isotope composition in inclusion enclave. These techniques combing the inclusion homogeneous temperature can be applied to study on gas-rock correlation directly and gas migration, filling and formation ages. Technique of on-line determination individual gas carbon isotope composition in kerogen and bitumen thermal pyrolysis is developed. It is applied to determine the source of natural is kerogen thermal degradation or oil pyrolysis. Method of on-line determination individual gas carbon isotope composition in rock thermal simulation has being improved. Based on the "95"former research, on-line determination individual gas carbon isotope composition in different type of maceral and rocks thermal pyrolys is has been determined. The conclusion is that carbon isotope composition of benzene and toluene in homogenous texture kerogen thermal degradation is almost same at different maturity. By comparison, that in mixture type kerogen thermal pyrolysis jumps from step to step with the changes of maturity. This conclusion is a good proof of gas-rock dynamic correlation. 3. Biomarker of rock can be determined directly through research. It solves the problems such as long period preparing sample, light composition losing and sample contamination etc. It can be applied to research the character of source rock and mechanism of source rock expulsion and the path of hydrocarbon migration etc. 4. The process of hydrocarbon dynamic generation in source rock can be seen at every stage applying locating observation and thermal simulation of ESEM. The mechanism of hydrocarbon generation and expulsion in source rock is discussed according to the experiments. This technique is advanced in the world. 5. A sample injection system whose character is higher vacuum, lower leaks and lower blank has been built up to analyze inert gas. He,Ar,Kr and Xe can be determined continuously on one instrument and one injection. This is advanced in domestic. 7. Quality and quantity analysis of benzene ring compounds and phenolic compounds and determination of organic acid and aqueous gas analysis are applied to research the relationship between compounds in formation water and gas formation. This is another new idea to study the gas-rock correlation and gas formation. 8. Inclusion analysis data can be used to calculate the Paleo-fluid density, Paleo-geothermal gradient and Paleo-geopressure gradient and then to calculate the Paleo-fluid potential. It's also a new method to research the direction of hydrocarbon migration and accumulation. 9. Equipment of natural gas formation simulation is produced during the research to probe how the physical properties of rock affect the gas migration and accumulation and what efficiency of gas migrate and factors of gas formation and the models of different type of migration are. II study is focused on that if the source rocks of lower Paleozoic generated hydrocarbon and what the source rocks of weathered formation gas pool and the mechanism of gas formation are though many advanced techniques application. There are four conclusions. 1.The maturity of Majiagou formation source rocks is higher in south than that in north. There also have parts of the higher maturity in middle and east. Anomalous thermal pays important role in big size field formation in middle of basin. 2. The amount of gas generation in high-over maturity source rocks in lower Paleozoic is lager than that of most absorption of source rocks. Lower Paleozoic source rocks are effective source rocks. Universal bitumen exists in Ordovician source rocks to prove that Ordovician source rocks had generated hydrocarbon. Bitumen has some attribution to the middle gas pool formation. 3. Comprehensive gas-rock correlation says that natural gases of north, west, south of middle gas field of basin mainly come from lower Paleozoic source rocks. The attribution ratio of lower Paleozoic source rocks is 60%-70%. Natural gases of other areas mainly come from upper Paleozoic. The attribution ratio of upper Paleozoic source rocks is 70%. 4. Paleozoic gases migration phase of Erdos basin are also interesting. The relative abundance of gasoline aromatic is quite low especially toluene that of which is divided by that of methyl-cyclohexane is less than 0.2 in upper Paleozoic gas pool. The migration phase of upper Paleozoic gas may be aqueous phase. By comparison, the relative abundance of gasoline aromatic is higher in lower Paleozoic gas. The distribution character of gasoline gas is similar with that in source rock thermal simulation. The migration phase of it may be free phase. IH Comprehensive gas-rock correlation is also processed in Kuche depression Tarim basin. The mechanism of gas formation is probed and the gas formation model has been built up. Four conclusions list below. 1. Gases in Kuche depression come from Triassic-Jurassic coal-measure source rocks. They are high-over maturity. Comparatively, the highest maturity area is Kelasu, next is Dabei area, Yinan area. 2. Kerogen thermal degradation is main reason of the dry gas in Kuche depression. Small part of dry gas comes from oil pyrolysis. VI 3.The K12 natural gas lays out some of hydro-gas character. Oil dissolved in the gas. Hydro-gas is also a factor making the gas drier and carbon isotope composition heavier. 4. The mechanism and genesis of KL2 gas pool list as below. Overpressure has being existed in Triassic-Jurassic source rocks since Keche period. Natural gases were expulsed by episode style from overpressure source rocks. Hetero-face was main migration style of gas, oil and water at that time. The fluids transferred the pressure of source rocks when they migrated and then separated when they got in reservoir. After that, natural gas migrated up and accumulated and formed with the techno-genesis. Tectonic extrusion made the natural gas overpressure continuously. When the pressure was up to the critical pressure, the C6-C7 composition in natural gas changed. The results were that relative abundance of alkane and aromatic decreased while cycloalkane and isoparaffin increased. There was lots of natural gas filling during every tectonic. The main factors of overpressure of natural gas were tectonic extrusion and fluid transferring pressure of source rocks. Well preservation was also important in the KL2 gas pool formation. The reserves of gas can satisfy the need of pipeline where is from west to east. IV A good idea of natural gas migration and accumulation modeling whose apparent character is real core and formation condition is suggested to model the physical process of gas formation. Following is the modeling results. 1. Modeling results prove that the gas accumulation rule under cap layer and gas fraction on migration path. 2. Natural gas migration as free phase is difficult in dense rock. 3. Natural gases accumulated easily in good physical properties reservoirs where are under the plugging layer. Under the condition of that permeability of rock is more than 1 * 10~(-3)μm~(-1), the more better the physical properties and the more bigger pore of rock, the more easier the gas accumulation in there. On the contrary, natural gas canonly migrate further to accumulate in good physical properties of rock. 4. Natural gas migrate up is different from that down. Under the same situation, the amount of gas migration up is lager than that of gas migration down and the distance of migration up is 3 times as that of migration down. 5. After gas leaks from dense confining layer, the ability of its dynamic plug-back decreased apparently. Gas lost from these arils easily. These confining layer can confine again only after geology condition changes. 6. Water-wetted and capillary-blocking rocks can't block water but gases generally. The result is that water can migrate continuously through blocking rocks but the gases stay under the blocking rocks then form in there. The experiments have proved the formation model of deep basin gas.

运动与重定向时物-我、物-物空间表征的使用

Eight experiments tested how object array structure and learning location influenced the establishing and utilization of self-to-object and object-to-object spatial representations in locomotion and reorientation. In Experiment 1 to 4, participants learned either at the periphery of or amidst regular or irregular object array, and then pointed to objects while blindfolded in three conditions: before turning (baseline), after rotating 240 degrees (updating), and after disorientation (disorientation). In Experiment 5 to 8, participants received instruction to keep track of self-to-object or object-to-object spatial representations before rotation. In each condition, the configuration error, which means the standard deviation of the means per target object of the signed pointing errors, was calculated as the index of the fidelity of representation used in each condition. Results indicate that participants form both self-to-object and object-to-object spatial representations after learning an object-array. Object-array structure influences the selection of representation during updating. By default, object-to-object spatial representation is updated when people learned the regular object-array structure, and self-to-object spatial representation is updated when people learned the irregular object array. But people could also update the other representation when they are required to do so. The fidelity of representations will confine this kind of “switch”. People could only “switch” from a low fidelity representation to a high fidelity representation or between two representations of similar fidelity. They couldn’t “switch” from a high fidelity representation to a low fidelity representation. Leaning location might influence the fidelity of representations. When people learned at the periphery of object array, they could acquire both self-to-object and object-to-object spatial representations of high fidelity. But when people learned amidst the object array, they could only acquire self-to-object spatial representation of high fidelity, and the fidelity of object-to-object spatial representation was low.