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91.
A boundary-based scheme to inspect basic dimensions and surface defects on solder plates (terminations) of passive components by using the eigenvalues of covariance matrices was developed. The image of the passive component was initially processed to show only two terminations. The eigenvalues of covariance matrices for boundary points, which are equivalent to curvature measurements, then generate a one-dimensional representation describing the angle variations on termination boundaries. Since a single corner (intersection of two boundary edges) and jagged corners (a surface defect) are local deviations on termination boundaries, their locations will be represented as highly fluctuating eigenvalue waveforms. By setting an appropriate threshold on the eigenvalues, the surface defects and single corners on the termination boundaries can be identified. The basic dimensions of a passive component are determined simply by the distances between the detected single corners. Real passive components (0805 MLCCs) are testing samples to evaluate the performance of the proposed approach. Experimental results show that the proposed approach achieves precise identification for surface defects and measurement for the basic dimensions. The proposed approach is precise, rotation invariant and template free. Therefore, it is especially suitable for small batch production of various types of passive components. 相似文献
92.
Tsung-Hung Lin Hsiharng Yang Ching-Kong Chao Mau-Shiun Yeh 《Microsystem Technologies》2010,16(7):1215-1220
This paper presents a novel, precision process for fabricating a micro metal vertical probe array with various tip angles.
The fabrication process includes an inclined and multiple-exposure in ultraviolet (UV) lithographic and Ni electroforming
technology. Because of the light passing through an optical transparent homogenous material, the materials’ refractive index
results in light path deflection. By changing the photomask and workpiece inclination, controllable various tip angles can
be fabricated. The experimental results showed that micro metal vertical probes with 54°, 60° and 68° tip angles are achieved.
The micro-pyramidal vertical probe array can be used in vertical-type probe cards without the conventional complicated assembly. 相似文献
93.
Jung-Hsiung Shen Sung-Wei Yeh Dershin Gan Koho Yang Hsing-Lu Huang Shih-Wei Mao 《Journal of Electronic Materials》2010,39(10):2352-2358
Low-temperature preparation of transparent conducting electrodes is essential for flexible optoelectronic devices. Tin-doped
In2O3 films with high transparency and low electrical resistance were prepared at room temperature using a radiofrequency ion beam
sputtering system. Specimens with a low sheet resistivity of 10−4 Ω cm and a high visible-light transmittance of 85% to 90% were obtained. Hall measurements were used to determine mobility
and carrier concentration, and the effects on resistivity are discussed. 相似文献
94.
Chien-Hung Yeh Chi-Wai Chow Yu-Fu Wu Fu-Yuan Shih Sien Chi 《Optical Fiber Technology》2010,16(3):178-181
High capacity time-division-multiplexed passive optical network (TDM-PON) is an emerging fiber access network that deploys optical access lines between a carrier’s central office (CO) and a customer sites. In this investigation, we demonstrate and analyze the continuous wave (CW) upstream effect in TDM-PONs. Besides, we also propose and design a protection apparatus in each optical network unit (ONU) to avoid a CW upstream traffic in TDM-PONs due to sudden external environment change or ONU failure. When an upstream CW injection occurs in TDM access network, the protection scheme can stop the CW effect within a few ms to maintain the entire data traffic. 相似文献
95.
Theoretical and experimental studies of the diffusional deposition of aerosols on model niters of intermediate packing density are reported. At low Reynolds number (Re« 1) and intermediate porosity (0.01 < α < 0.4), the Kuwabara flow field is applicable for parallel staggered model filters, and the diffusional deposition efficiency can be expressed as A = 2.92 n [(l-a)/k]1/3 Pe ?2/3. By applying a correction factor based on the ratio of pressure drops to this equation, the deposition efficiency for a fan model filter is n = A Pe ?2/3, where A has a value of 2.4–2.6 for α = 0.05–0.4. The efficiency increases with the fiber solidity, α for the parallel staggered filter, but is essentially independent of a for the fan model filter. Experimental results of diffusional deposition of ultrafine aerosols on wire screens which is used as a fan model filter has been performed. Summary data on screens and the fan model filter reported in the literature show that the single fiber efficiency is independent of the solid volume fraction and can be expressed as n = 2.7 Pe ?2/3 where Pe is the Peclet number (over the range of 0.02 < a < 0.35). The small difference between the experimental data and theory can be explained by the approximate nature of the flow field used in the theory. 相似文献
96.
Vikas Nandwana Rubul Mout Yi-Cheun Yeh Stefan Dickert Mark T. Tuominen Vincent M. Rotello 《Journal of Inorganic and Organometallic Polymers and Materials》2013,23(1):227-232
Here we demonstrate patterning of protein/quantum dot hybrid bionanostructures via electrostatic assembly of engineered negatively charged fluorescent protein with positively charged CdSe/ZnS QD patterns formed through e-beam lithography and post-patterning modification with cationic ligands. 相似文献
97.
Jen‐Taut Yeh Yu‐Ching Lai Hai Liu Yao‐Chi Shu Chi‐Yuan Huang Kuo‐Shien Huang Kan‐Nan Chen 《Polymer International》2011,60(1):59-68
The influence of formation temperature on the ultradrawing properties of ultrahigh‐molecular‐weight polyethylene/carbon nanotube (UHMWPE/CNT) fiber specimens is investigated. Gel solutions of UHMWPE/CNT with various CNT contents were gel‐spun at the optimum concentration and temperature but were cooled at varying formation temperatures in order to improve the ultradrawing and tensile properties of the UHMWPE/CNT composite fibers. The achievable draw ratio (Dra) values of UHMWPE/CNT as‐prepared fibers reach a maximum when they are prepared with the optimum CNT content and formation temperature. The Dra value of UHMWPE/CNT as‐prepared fibers produced using the optimum CNT content and formation temperature is about 33% higher than that of UHMWPE as‐prepared fibers produced using the optimum concentration and formation temperature. The percentage crystallinity (Wc) and melting temperature (Tm) of UHMWPE/CNT as‐prepared fiber specimens increase significantly as the formation temperature increases. In contrast, Wc increases but Tm decreases significantly as the CNT content increases. Dynamic mechanical analysis of UHMWPE and UHMWPE/CNT fiber specimens exhibits particularly high α‐transition and low β‐transition, wherein the peak temperatures of α‐transition and β‐transition increase dramatically as the formation temperature increases and/or CNT content decreases. In order to understand these interesting drawing, thermal and dynamic mechanical properties of the UHMWPE and UHMWPE/CNT as‐prepared fiber specimens, birefringence, morphological and tensile studies of as‐prepared and drawn fibers were carried out. Possible mechanisms accounting for these interesting properties are proposed. Copyright © 2010 Society of Chemical Industry 相似文献
98.
Machine Hsie Yueh-Feng HoChih-Tsang Lin I-Cheng Yeh 《Expert systems with applications》2012,39(5):4874-4881
The Artificial Neural Network (ANN) and the nonlinear regression method are commonly used to build models from experimental data. However, the ANN has been criticized for incapable of providing clear relationships and physical meanings, and is usually regarded as a black box. The nonlinear regression method needs predefined and correct formula structures to process parameter search in terms of the minimal sum of square errors. Unfortunately, the formula structures of these models are often unclear and cannot be defined in advance. To overcome these challenges, this study proposes a novel approach, called “LMGOT,” that integrates two optimization techniques: the Levenberg-Marquardt (LM) Method and the genetic operation tree (GOT). The GOT borrows the concept from the genetic algorithm, a famous algorithm for solving discrete optimization problems, to generate operation trees (OTs), which represent the structures of the formulas. Meanwhile, the LM takes advantage of its merit for solving nonlinear continuous optimization problems, and determines the coefficients in the GOTs that best fit the experimental data. This paper uses the LMGOT to investigate the data sets of pavement cracks from a 15-year experiment conducted by the Texas Departments of Transportation. Results show a concise formula for predicting the length of pavement transverse cracking, and indicate that the LMGOT is an efficient approach to building an accurate crack model. 相似文献
99.
A low-viscosity 60 SnO–40 P2O5 (mol%) glass was reheated at 280 °C (about 45 °C above the glass-transition temperature) for 20 min in various atmospheres
(Ar, air, and O2), then the structure- and surface-related properties were examined. It was found that increase in
\textP\textO 2 {\text{P}}_{{{\text{O}}_{ 2} }} increases surface hardness, reduces optical transmittance, and improves chemical durability. The above phenomena are explained
in terms of the increased oxidation tendency of Sn2+ to Sn4+ on the glass surface during reheating in increased
\textP\textO 2 {\text{P}}_{{{\text{O}}_{ 2} }} . 相似文献
100.
This study applies the four-stage DEA procedure to calculate the energy efficiency of 23 regions in Taiwan from 1998 to 2007. After controlling for the effects of external environments, only Taipei City, Chiayi City, and Kaohsiung City are energy efficient. Note that Kaohsiung City reaches the efficiency frontier due to the adjustment via partial environmental factors such as higher education attainment and transport vehicles. We also find a worsening trend for Taiwan’s energy efficiency. Not only is there a gap of energy efficiency between Taiwan’s metropolitan areas and the other regions, but the gap has also widened in recent years. Those inefficient counties should be given priority and the savings potential. Except for road density, the evidence indicates that each environmental factor has partial incremental effects on input slacks. As more cars and motorcycles are unfavorable externalities affecting partial energy efficiency, the central government should help local governments retire inefficient old motor vehicles, encourage energy-saving vehicle models, and provide convenient mass transportation systems. Besides, people with higher education cause industrial energy inefficient in Taiwan. The conscious of effective energy saving is necessary to schools, communities, and employee accordingly. 相似文献