基于加权POCS的图像超分辨率重建

对凸集投影(POCS)图像超分辨率重建算法中的残差修复阈值选取问题进行分析,提出一种基于图像超分辨率重建的改进算法。改变传统POCS算法中固定残差修复阈值模式,通过引入低分辨率图像清晰度这一先验信息,用表征图像相对清晰度的参数控制阈值,从而实现整个重建过程阈值动态选取。实验结果证明,该算法能提高残差计算和阈值选取的针对性,对提升重建图像的清晰度及信噪比具有较好的效果。     

Radiation effects and re-crystallization mechanism of syndiotactic polystyrene with β′-crystalline form

The double melting behavior of syndiotactic polystyrene (sPS) with β′-form crystallites was systematically investigated by several analytical techniques, including differential scanning calorimetry (DSC), polarized light microscopy (PLM), transmission electron microscopy (TEM), as well as wide-angle and small-angle X-ray scattering (WAXD, SAXS). For preventing the possible chain re-organization during intermediate melting, a high-energy electron beam (e-beam) radiation was carried out on the melt-crystallized samples to chemically cross-link the amorphous chains between lamellar crystals. The WAXD intensity profiles of the irradiated sPS samples revealed that no crystal transformation took place, and the crystallinity fraction remained unchanged for a received dose up to 2.4 MGy. As the received dose was increased, however, the high melting temperature peak was gradually diminished and finally disappeared after 1.8 MGy e-beam radiation, suggesting that the double melting phenomenon was mainly attributed to the melting/re-crystallization/re-melting behavior. The re-crystallization mechanism of sPS samples was studied using DSC and PLM to reveal the effects of heating rate and annealing temperature on the Avrami exponent and re-crystallization rate constant. In addition, the lamellar morphologies of the re-crystallized samples were also investigated by means of SAXS and TEM. With increasing heating rate or annealing temperature, the derived Avrami exponent was slightly decreased from 1.4 to 1.1; in comparison, the re-crystallization rate showed a shallow maximum at a rate of 10 °C/min, but it became evidently reduced at high annealing temperatures. Based on the morphological observations, we proposed that the re-crystallization of β^′-form sPS crystals involved with the presence of broad lamellar thickness distribution as well as abundant irregular loose folding chains on the lamellar surfaces, which became tightened and crystallized into the un-melted lamellae when the neighboring thinner lamellae trapped in-between were melted. Thus, the high melting temperature is dependent on the average thickness of lamellae consisting of the un-melted lamellae developed initially and thickened ones associated with re-crystallization.     

Superconductivity of (Y1−xREx)Ba2Cu3O7#x2212;δ system

Polycrystalline samples of the superconducting oxides (Y_1–x RE _x )Ba₂Cu₃O_7– (RE = Er and Dy) withx=0, 0.2, 0.4, 0.6, 0.8 and 1.0 were prepared. From the X-ray diffraction and the electrical resistivity measurements, it was found thatT _c and the unit cell volume have common peaks nearx0.4. Close examination of previously published data on the (Y_1–xRE _x )Ba₂Cu₃O_7– system also indicate that an anomaly exists nearx–0.4. This anomaly is ascribed to an anomalous change of in oxygen nearx0.4.     

An optimal design of solar water heating systems

Abstract

Based on the seismicity and tectonics of Taiwan area, a set of potential earthquake sources is identified. Using available attenuation laws and fault‐rupture model, the individual influences of potential sources are integrated into the probability distribution of maximum annual intensity and peak acceleration. The results are presented in the form of seismic risk maps for a 475‐year return period. Based on the result of this study, it concludes that the seismic hazard potential for the central region is moderate, but it is high for east‐coast region.

This paper also presents a reliability analysis method for safety evaluation of buried pipelines in Taiwan region. The results of the reliability analysis of the buried pipelines subjected to earthquake ground accelerations are presented and a fragility result for peak ground acceleration (PGA) studies is also constructed.     

A Study on the Site Vibration for the Breakage Analysis of Glass Insulators on the High-Speed Railway

This paper has investigated the possibility of glass insulator breakage by resonance and accelerated degradation based on an analysis of natural frequency characteristics of glass insulators on the KTX overhead line and behavioral characteristics of the overhead line on site. The natural frequencies were formed within the range of 10 kHz, and the largest amplitude was observed at 5.15 kHz. The largest frequency that was imposed on strut tube glass insulators was 80 Hz with 1.13 g of vertical vibration in the viaduct section, the largest vertical vibration (0.38 g) was detected at 103 Hz in the open route section. When site frequency and natural frequency of strut tube glass insulators were compared in terms of characteristics, the resonance was not the same. In both the viaduct and open route sections, it seems that the impact by vertical vibration in strut tube glass insulators is large. Through this study, therefore, it has been confirmed that the failure of the glass insulator has nothing to do with resonance. In addition, no damage was detected in the accelerated degradation test.     

改性棉活性染料的染色性能分析

采用阳离子改性剂对棉纤维进行阳离子化改性,通过单因素试验分析得到优化的染色工艺,并比较了采用优化染色工艺、同一颜色不同型号的14种活性染料上染改性棉纤维的染色性能,挑选出最适合此工艺、此改性剂的四种活性染料。并再次用这四种染料对原棉和改性棉进行了染色,并比较其上染率和固色率。     

连续旋转型光纤捷联惯导系统角速度误差补偿

旋转调制技术在有效抑制惯性器件漂移的同时,也使测量误差更加复杂,只有对这些误差进行补偿,才能发挥旋转调制的效果。为此分析了光纤陀螺敏感轴与旋转轴间不正交角、旋转轴涡动、时间不同步量、敏感轴间不正交角等误差造成的影响,建立了各自的误差补偿模型,并设计了一种基于单轴转台和单元体自身旋转的误差标定方法。结果显示,温补后的敏感轴与旋转轴之间不正交角标定精度优于0.2″,敏感轴之间不正交角标定精度优于1.4″,时间不同步量的标定精度优于0.06ms,经旋转调制和误差补偿后的等效光纤陀螺漂移由0.050°/h改善至0.015°/h。为低成本高精度惯导系统的实现建立了基础。     

火电机组甩50%负荷试验操作浅析

对于火电机组甩负荷试验,高压旁路控制是一个重点。实例呈现未设置快开保护功能的小容量启动旁路如何手动控制旁路开度,该做哪些准备,以完成机组甩50%负荷试验。同时,阐述甩50%负荷试验前及试验中的注意事项,以期为同类型启动旁路机组甩负荷试验提供参考。     

Finite-Size Effects in O and CO Adsorption for the Late Transition Metals

Gold is known to become significantly more catalytically active as its particle size is reduced, and other catalysts are also known to exhibit finite-size effects. To understand the trends related to finite-size effects, we have used density functional theory to study adsorption of representative adsorbates, CO and O, on the late transition metals Co, Ni, Cu, Ir, Pd, Ag, Rh, Pt and Au. We studied adsorption energies and geometries on 13-atom clusters and compared them to the fcc(111) and fcc(211) crystal facets. In all cases, adsorbates were found to bind significantly more strongly to the 13-atom clusters than to the extended surfaces. The binding strength of both adsorbates were found to correlate very strongly with the average coordination number of the metal atoms to which the adsorbate binds, indicating that the finite-size effects in bonding are not specific to gold.     

Study on dyeable polypropylene fiber and its properties

A disperse dyeable polypropylene fiber has been prepared by admixing polystyrene to the polymer prior to extrusion. Polystyrene has been synthesized at suitable molecule weight and narrow mol wt distribution. The dyeability, mechanical properties, shrinkage, degree of crystallinity, and orientation of pure polypropylene or the blend fibers with different amount of polystyrene were investigated. In addition, the structure of the blend containing 4 and 6% polystyrene was also studied to explain the interesting dyeing behavior of the blend fibers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3172–3176, 2001