A multi-frame image super-resolution method

Multi-frame image super-resolution (SR) aims to utilize information from a set of low-resolution (LR) images to compose a high-resolution (HR) one. As it is desirable or essential in many real applications, recent years have witnessed the growing interest in the problem of multi-frame SR reconstruction. This set of algorithms commonly utilizes a linear observation model to construct the relationship between the recorded LR images to the unknown reconstructed HR image estimates. Recently, regularization-based schemes have been demonstrated to be effective because SR reconstruction is actually an ill-posed problem. Working within this promising framework, this paper first proposes two new regularization items, termed as locally adaptive bilateral total variation and consistency of gradients, to keep edges and flat regions, which are implicitly described in LR images, sharp and smooth, respectively. Thereafter, the combination of the proposed regularization items is superior to existing regularization items because it considers both edges and flat regions while existing ones consider only edges. Thorough experimental results show the effectiveness of the new algorithm for SR reconstruction. (C) 2009 Elsevier B.V. All rights reserved.

Gaussian diffraction model for Sb thin films in super-resolution near-field structure

SPIE

Ultrahigh-resolution fiber-optic image guides derived from microstructured polymer optical fiber preforms

Ultrahigh-resolution fiber-optic image guides-fused image fiber, faceplate, and taper-were fabricated by using microstructured polymer optical fiber (MPOF) preforms composed of two polymers: polymethylmethacrylate and polystyrene. The pixel diameter in the resultant MPOF-based image guides was as small as 3 mu m. The imaging capabilities of these types of fiber-optic elements were demonstrated. (C) 2009 Optical Society of America

丙型肝炎病毒(HCV)株的全基因组序列测定: 完成HCV 基因型6 全套17 个亚型基因组的测序

丙型肝炎病毒（Hepatitis C virus, HCV）的全基因组序列测定，曾经由于许多方面 的条件限制而难于完成。但是，其对于研究HCV 分子病毒学、流行病学、进化和致 病性却至关重要，特别是在临床应用中，不同序列的基因型决定α-干扰素治疗的不同 效果。在本研究完成之前，HCV 基因型6 仅有6 个亚型有其全基因组序列。因此， 本研究的主要目的在于，测定HCV 变异株代表基因型6 其余的11 个亚型和新亚型的 全基因组序列，并深入分析。 本研究从样品分别来自于中国、泰国，和在美国及加拿大生活的东南亚国家移民 的HCV 感染者。因为样品有限，改良传统的PCR 方法，摸索出“桥”和“岛”DNA 全序列扩增法，从每例样品100μl 血清或从100μl 血清中获得的cDNA 中测定了13 个HCV 全基因组核苷酸序列。 以来源于Genbank 的已知基因型6 的七个全长序列为参考对所测定的13 个亚型 全序列进行共同分析显示，这些全基因组核苷酸的两两比较相似率变化范围为 71.9%--82.7%，著地， 这四对序列间的相同率高于标准定义的HCV 基因亚型之间的 范围值75%-80%。为了进一步理解和证实这些亚型间的遗传相似性，本研究还测定 了代表这4 对亚型的病毒原型株的全基因序列，结果显示了相同的核苷酸水平上的变 异范围，这为HCV 基因亚型的分类提供了新的认识，亦强调了全长序列对于分类的 重要性。 从系统发育方面的分析证实，本研究所测得的13 个分离株都属于基因型6。在系 统发育树上，每个病毒株代表一个独立的枝。并形成了高度分化的HCV 基因型6 分 枝，从而清楚显示，各亚型的独立分布。本研究至此完成了基因型6 中17 个亚型的 全序列测定，而km41 和gz52557 因缺乏其临床上和流行病学上的多个感染病例的证 实，而继续保留其亚型未命名状态。结合来源于Los Alamos HCV database 的基因型6 的已知部分序列的变异株进一步分析，发现各相近亚型变异株均来自东南亚或东南亚国家移民，这提示了这些HCV 的相同感染源。 为了探讨HCV 夫妻间传播的可能性，本研究还测定了来自于泰国的两位感染 HCV 的献血员及其感染HCV 的配偶。这4 个基因序列C-0044 和C-0046 之间核苷 酸相同率为98.1%，而C-0185 和 C-0192 之间为97.8%。文献研究感染HCV 的夫妇 间的部分亚基因序列的相同率为96.3%至100%，本研究结果与此范围相符，并第一 次用全基因组序列提示了HCV 在夫妻间传播的可能性。 本研究还测定了基因型6 的另一个变异株的全基因组序列：HK6554，香港的某患 者，与上文中的GX004 一起，均为静脉吸毒者，并共同感染了HCV 和HIV-1。分析 结果还表明了一种趋势，即是在中国南方，基因亚型6e 有从以前的地方性传播方式 转为现有的流行性传播方式。这种转变可能由于静脉吸毒感染HCV 的人群的网络传 播而加快。 综上，本研究用传统PCR、简并引物结合链特异引物的方法有效地测定了共21 个病毒株的全基因序列。该方法也可用于其它分子流行病学的研究，特别在测定珍贵 的病毒序列然而样品量又受限时。本研究所测定的全基因组序列代表HCV 中最古老、 分化最多、地方性传播、又可能动物源性的基因型6 的全套17 个亚型。这有助于进 一步理解HCV 基因亚型的分类意义、更准确评价HCV 的进化和起源，亦有助于发 现HCV 新的变异株和提高临床诊断、治疗，为将来HCV 的流行及公众健康的预测、 预防和疫苗的制备奠定了坚实的分子遗传学基础。

HIGH-RESOLUTION PHOTOLUMINESCENCE STUDIES OF (211) CDTE GROWN ON (211)B GAAS SUBSTRATE

Sharp and rich photoluminescence lines accociated with free exciton (FE), excitons bound to neutral acceptors (A0X) and donors (D0X) in molecular beam epitaxially (MBE) grown (211) CdTe/(211)B GaAs have been reported for the first time. The results show that the (211) CdTe/(211)B GaAs grown under optimized conditions could have as high a crystal perfection as those grown on lattice-matched substrates.

INVESTIGATION OF THE GROWN DIAMOND (100) SURFACE USING HIGH-RESOLUTION ELECTRON-ENERGY LOSS SPECTROSCOPY

The diamond (100) facets deposited at initial 1.0% CH4 have been investigated using high resolution electron energy loss spectroscopy (HREELS). The diamond (100) facets grown at 800-degrees-C are terminated by CH2 radicals, and there is no detectable frequency shift compared with the characteristic frequencies of molecular subgroup CH2. Beside the CH2 vibration loss, CH bend loss (at 140 meV) of locally monohydrogenated dimer is detected for the diamond (100) facets grown at 1000-degrees-C. Dosing the (100) facets grown at 800-degrees-C with atomic hydrogen at 1*10(-6) mbar, the loss peak at 140 meV appears. It is suggested that there are enough separately vacant sites and uniformly dispersed monohydrogenated dimers on (100) facets. This structure relaxes the steric repulsion between the adjacent hydrogen atoms during the diamond (100) surface growth.

HIGH-RESOLUTION DLTS AND ITS APPLICATION TO LATTICE-MISMATCH-INDUCED DEEP LEVELS IN INGAP

A new method of differentiating the deep level transient spectroscopy (DLTS) signal is used to increase the resolution of conventional DLTS. Using this method, more than one single deep level with small differences in activation energy or capture cross section, which are often hard to determine by conventional DLTS, can be distinguished. A series of lattice-mismatched InxGa1-xP samples are measured by improved DLTS to determine accurately the activation energy of a lattice-mismatch-induced deep level. This level cannot be clearly determined using conventional DLTS because the two signals partly overlap each other. Both the signals are thought to originate from a phosophorus vacancy and lattice-mismatch-induced defect.

ON THE RATE-EQUATIONS OF SEMICONDUCTOR-LASERS FOR MEASURING SPONTANEOUS EMISSION FACTOR

The rate equations used for measuring spontaneous emission factor beta is examined through the comparison of numerical results, The results show that beta obtained by using total spontaneous emission rate R(sp) = N/tau sp is about double of that using R(sp) = BN2, The magnitude difference between the measured beta and that predicted by classical theory [8] will disappear by using more reasonable R(sp) = BN2. The results also show that the magnitude of beta may be underestimated by ignoring the nonradiative recombination rates.

NEW METHOD FOR ACQUIRING A HIGH-RESOLUTION ATMOSPHERIC RAYLEIGH-MIE SPECTRUM

A new method using an atomic-resonance filter and deconvolution techniques has been developed to acquire high-resolution spectra of atmospheric Rayleigh-Mie scattering. In the deconvolution process, the difficulty of the undetermined division 0/0 is overcome by a fitting method. Preliminary laboratory experimental results on 90-deg scattering show that with a signal-to-noise ratio of 20, the scattered Rayleigh-Mie spectrum may be retrieved in agreement with the theoretical analysis.

Cooperative spontaneous emission of excitons in the semiconductor microcavity

We have studied the spontaneous emission of polarized excitons in the GaInP/AlGaInP VCSEL from 30K to room temperature. It is observed that the spontaneous emission peak enters and leaves the resonant regime. At the resonant regime, the emission intensities of the perpendicular and horizontal polarized exciton are enhanced at different ratio to those in non-resonant regime. These experiment results are explained through the dressed exciton theory of the semiconductor microcavity device. From this theory, the intensity enhancement and the polarization dependence are understood as cooperative emission and the microcavity anisotropy.