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991.
Simultaneous detection of ultraviolet and infrared radiation in a single GaN/GaAlN heterojunction 总被引:1,自引:0,他引:1
Jayasinghe RC Ariyawansa G Dietz N Perera AG Matsik SG Yu HB Ferguson IT Bezinger A Laframboise SR Buchanan M Liu HC 《Optics letters》2008,33(21):2422-2424
Results are presented for a dual-band detector that simultaneously detects UV radiation in the 250-360 nm and IR radiation in the 5-14 microm regions with near zero spectral cross talk. In this detector having separate UV- and IR-active regions with three contacts (one common contact for both regions) allows the separation of the UV and IR generated photocurrent components, identifying the relative strength of each component. This will be an important development in UV-IR dual-band applications such as fire-flame detection, solar astronomy, and military sensing, eliminating the difficulties of employing several individual detectors with separate electronics-cooling mechanisms. 相似文献
992.
993.
In this paper the laws of motion of classical particles have been investigated in a non-commutative phase space. The corresponding non-commutative relations contain not only spatial non-commutativity but also momentum non-commutativity. First, new Poisson brackets have been defined in non-commutative phase space. They contain corrections due to the non-commutativity of coordinates and momenta. On the basis of this new Poisson brackets, a new modified second law of Newton has been obtained. For two cases, the free particle and the harmonic oscillator, the equations of motion are derived on basis of the modified second law of Newton and the linear transformation (Phys. Rev. D, 2005, 72: 025010). The consistency between both methods is demonstrated. It is shown that a free particle in commutative space is not a free particle with zero-acceleration in the non-commutative phase space, but it remains a free particle with zero-acceleration in non-commutative space if only the coordinates are non-commutative. 相似文献
994.
Establishment of Configuration with Optimized Current Profile in Pellet Fuelled Discharge on HL-2A 下载免费PDF全文
A sawtooth-free period is produced following the pellet injection in the pellet fuelled discharge of qa = 3.4 (where qa is the safety factor at the plasma boundary) in the HL-2A tokamak. Establishment of the current profile such as in the hybrid scenario is studied under the condition of pellet injection in HL-2A. It is shown that a q-profile of weak negative shear is produced immediately after the pellet injection, and it then evolves to a broad flat profile with q0 〉 1 (where qo is the safety factor at the centre). The measured MHD mode structures evidence consistencies of the evaluated q-profile with locations of the q = 1 surface in the sawtoothing period and of the q = 2 surface in the sawtooth-free period. TRANSP analysis indicates that the energy confinement is enhanced substantially during and after pellet injection, which is resulted from the q-profile optimization and the plasma density peaking. 相似文献
995.
Molecular dynamics simulations are performed to investigate the behaviour of helium atoms in titanium at a temperature of 30OK. The nucleation and growth of helium bubble has been simulated up to 50 helium atoms. The approach to simulate the bubble growth is to add helium atoms one by one to the bubble and let the system evolve. The titanium cohesion is based on the tight binding scheme derived from the embedded atom method, and the helium-titanium interaction is characterized by fitted potential in the form of a Lennard-Jones function. The pressure in small helium bubbles is approximately calculated. The simulation results show that the pressure will decrease with the increasing bubble size, while increase with the increasing helium atoms. An analytic function about the quantitative relationship of the pressure with the bubble size and number of helium atoms is also fitted. 相似文献
996.
Cellular cell pattern evolution of cylindrically-diverging detonations is numerically simulated successfully by solving two-dimensional Euler equations implemented with an improved two-step chemical kinetic model. From thesimulation, three cell bifurcation modes are observed during the evolution and referred to as concave front focusing, kinked and wrinkled wave front instability, and self-merging of cellular cells. Numerical research demonstrates that the wave front expansion resulted from detonation front diverging plays a major role in the cellular cell bifurcation, which can disturb the nonlinearlyself-sustained mechanism of detonations and finally lead to cell bifurcations. 相似文献
997.
We present first-principles studies on the transport properties of oligomers, polyphenyl dithiol, PP(n)DTs, sandwiched between two Al(1 0 0) electrodes. The variation of the current-voltage curve for PP(2)DT in different tilt angles is investigated systematically. The results indicate that PP(2)DT can be functioned as a molecular switch controlled by molecular conformation. We also study the variation of the equilibrium conductance and current-voltage properties of PP(n)DT as a function of n. 相似文献
998.
利用量子化学从头计算的方法对甲基乙烯醚的两个异构体之间的转化,羟基与顺式-甲基乙烯醚和反式-甲基乙烯醚的加成反应,以及羟基提取甲基上的氢原子的反应机理进行了研究.研究结果表明:顺式-甲基乙烯醚比反式-甲基乙烯醚更加稳定,在QCISD/6-31G(d,P)//BHandHLYP/6.311 G(d,P)理论水平下,OH加到顺式-甲基乙烯醚1号住的碳原子上需要跨越的能垒比其它反应通道需要跨越的能垒少7.5~34 KJ/mol,因此是主要的反应通道,而OH加在反式.甲基乙烯醚2号位的碳原子上所需要跨越的能垒比其它反应路径所需要跨越的能垒少8.3~26.7 kJ/mol,因此是主要的反应路径.利用经典过渡态理论计算了总的速率常数 相似文献
999.
Chun‐Syong Liao Jiann‐Shing Wu Chih‐Feng Wang Feng‐Chih Chang 《Macromolecular rapid communications》2008,29(1):52-56
The B‐ala/AIBN PBZ system has a high extent of ring‐opening of oxazine because phenol‐containing oligomers are formed at the early stage of the curing process. As a result, the B‐ala/AIBN PBZ system possesses a relatively stronger intramolecular hydrogen bonding and lower surface energy than the pure B‐ala system at low temperature curing. In this context, poly(4‐vinyl pyridine), poly(4‐vinyl phenol) thin films and polycarbonate substrates, which lack liquid resistance, possess low surface free energy after modification with B‐ala/AIBN = 5/1 PBZ.
1000.
基于改进的空域相关的多聚焦图像融合 总被引:2,自引:1,他引:1
提出了一种简单有效的像素级多聚焦图像融合方法。针对正交小波变换缺乏平移不变性而产生视觉失真的缺陷,采用Atrous算法将原图像分解在不同频率域上。Atrous算法先将滤波器h0(n),h1(n)各点间插入适当的零值后再与低频信号做卷积,故又称为"多孔算法"。将具有抑制噪声性能的空阈相关法作为高频子图像的融合规则,选取相关性强边缘特征显著的点作为最终融合子图像的像素点。实验表明,由此融合的图像能完好的保留边缘纹理信息。融合后的图像在客观评价和主管视觉效果上均有提高。 相似文献