一种独特和可靠的厚/薄铜复合PWB

本文论述一种厚/薄铜复合PWB(及其可靠性),它允许PWB设计者在厚铜和薄铜之间以任何希望的图形进行随意选择,以使电源模块/分配电路可以和精细图形特征一起集成,从而适应离I/O数半导体封装的要求。     

An expert system for XPLE cable deterioration diagnosis and life forecasting

The recent increase in the demand for power in urban areas has caused changes in the way power is supplied. Underground distribution systems have been introduced for convenience in urban areas and to prevent injuries in case of a crisis. As a result, many new types of power cables are being used. One type, XPLE cables (also called CV cables) have been rapidly taking the place of conventional cables such as OF or SL cables since the 1960s because of their relatively easy installation and maintainability. However, distribution cables used under severe environmental conditions deteriorate rapidly (due mainly to water treeing), and some cables experience insulation breakdown. Therefore, many diagnostic methods have been developed, though they have not been very effective. By combining methods, a high reliability can be achieved in comparison to the use of a single method. However, processing the data is difficult for on-site personnel, so many experts are required. But there is a lack of qualified experts, hence we have turned to the development of expert systems.     

Evaluation of Morphology—Stable Critical Size of KNbO3 Crystals

Skeletal form of KnbO3 crystals growing in Li2B4O7 solvent was in-situ observed at 900℃ and it was found that shallow depression started to develop on the surface of KnbO3 crystals when the crystal size exceeded several micron,typically 7 micron.Based on the quantitative criterion derived by Chernov,the estimated critical size of KNbO3 crystals was 1 micron,which was consistent with the experimental measurement.The kinetic coefficients,Kcorner and Kcr,in the criterion were experimentally obtained in the diffusive-convective and diffusive-advective flow states respectively.     

Quantitative evaluation of generator power control effect of FACTS controllers for power system stabilization

The advancement of power electronics technologies has significantly developed the power system stabilizing controllers. Quantitative as well as qualitative evaluation of their effectiveness in power systems is a matter of great importance for the feasibility investigation of these apparatus. In this paper, the possible control region of FACTS controllers with series and/or shunt configuration in a single machine to infinite bus system is formulated in the powerangle curve with a set of algebraic equations. The effectiveness of TCPST (Thyristor‐Controlled Phase Shifting Transformer), SSSC (Static Synchronous Series Compensator), and TCSC (Thyristor‐Controlled Series Compensator) for the improvement of the transient stability is evaluated quantitatively as a numerical example. The correctness of the proposed method has been confirmed by analysis based on the electromagnetic transients simulation with a detailed system model. © 2001 Scripta Technica, Electr Eng Jpn, 138(3): 43–51, 2002     

Interconnected power systems with superconducting magnetic energy storage

The objective of this work is to discuss the concept of back‐to‐back interconnection systems with energy storage, especially with a Superconducting Magnetic Energy Storage (SMES) incorporated into a back‐to‐back DC link. In this case, each converter of the back‐to‐back system is used as a power conditioning system for the SMES coils. Since the AC–DC converter can be designed independently of the frequency of the power system, a two‐way switch is connected to the AC side of each converter. This two‐way switch can select the interconnected power systems. By using the two‐way switches, this system can provide the stored energy in the SMES system to each interconnected power system through two AC–DC converters. For instance, lower‐cost power of each power network can be stored through two converters during the off‐peak hours and made available for dispatch to each power network during periods of demand peak. Then this system increases the reliability of electric power networks and enables the economical operations depending on the power demand. This paper describes the unique operations of the back‐to‐back interconnection with SMES and discuses the optimal SMES configuration for a 300‐MW‐class back‐to‐back interconnection. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(2): 37–43, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20482     

Planar AlGaAs/GaAs heterojunction bipolar transistors fabricatedusing selective W-CVD

The authors describe a planar process for the AlGaAs/GaAs HBTs in which collector vias are buried selectively, even to the base layers, with chemical vapor deposited tungsten (CVD-W) films. By using WF₆ /SiH₄ chemistry, W could be deposited on Pt films, which were overlapped 50 nm thick on the AuGe-based collector electrodes, without depositing W on the surrounding SiO₂ layers. Current gains of planar HBTs with 3.5-μm×3.5-μm emitters were up to 150, for a collector current density of about 2.5×10⁴ A/cm²     

Middle ear mucosa pathophysiology and healing processes in children with otitis media with effusion (OME)

Most otitis media with effusion (OME) in children heals spontaneously, but it is sometimes persistent and intractable. The major factors determining these different courses of OME are unknown. Identifying such factors would be clinically helpful. Factors affecting on the outcome of OME were studied experimentally and clinically. In animal experiment OME was induced in rabbit by occluding the Eustachian tube. Clinical study was conducted by investigating a histology of the middle ear mucosa, sampled from 64 children with OME (87 ears) who underwent middle ear tube ventilation. Furthermore, these cases studied how the degree of mastoid pneumatization before and after treatment, changes in the volume of the middle ear air cavity and the course after removal of the middle ear ventilation tube affected lesions in the middle ear mucosa. In animals, histology of the middle ear mucosa showed that in the early stages, the subepithelial layer of the middle ear mucosa was characterized by edematous hypertrophy and enlarged blood vessels. In later stages, it became fibrous as a result of chronic inflammation. These results suggest that lesions of the subepithelial layer are unlikely to recover. In clinical cases, histological changes in mucosal samples were rated on a two-point scale: changes in the epithelium and changes in the subepithelial layer. Re-pneumatization, a sign of healing of middle ear mucosal inflammation, was seen 12 months to 18 months after surgery. Among patients in whom the tube was left inserted for more than 18 months, only 11% had unfavorable outcomes and the recurrence rate was low. All patients who had recurrence of disease despite more than 18 months of tube insertion had prolonged inflammation in the middle ear mucosa. There results indicate that the air cavity returns to approximately normal degree of pneumatization more than 18 months after surgery, and that the extent of lesions in the middle ear mucosa, especially the subepithelial layer, is closely related to the healing of OME.     

Determination of horseradish peroxidase concentration using the chemiluminescence of Cypridina luciferin analogue, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin-3-one

The chemiluminescence of the Cypridina luciferin analogue, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin++ +-3-one (MCLA) was observed at 462 nm in the presence of horseradish peroxidase (HRP) and the total spectrum of light emitted was found to depend linearly on HRP concentration. Methods for the determination of HRP concentration using the chemiluminescence was investigated. HRP could be detected in the range from 100 pmol/L to 100 nmol/L under the optimum condition, H2O2 (10 mmol/L) and MCLA (10 mumol/L) at pH 5.8.     

Integrating local action elements for action analysis

In this paper, we propose a framework for human action analysis from video footage. A video action sequence in our perspective is a dynamic structure of sparse local spatial–temporal patches termed action elements, so the problems of action analysis in video are carried out here based on the set of local characteristics as well as global shape of a prescribed action. We first detect a set of action elements that are the most compact entities of an action, then we extend the idea of Implicit Shape Model to space time, in order to properly integrate the spatial and temporal properties of these action elements. In particular, we consider two different recipes to construct action elements: one is to use a Sparse Bayesian Feature Classifier to choose action elements from all detected Spatial Temporal Interest Points, and is termed discriminative action elements. The other one detects affine invariant local features from the holistic Motion History Images, and picks up action elements according to their compactness scores, and is called generative action elements. Action elements detected from either way are then used to construct a voting space based on their local feature representations as well as their global configuration constraints. Our approach is evaluated in the two main contexts of current human action analysis challenges, action retrieval and action classification. Comprehensive experimental results show that our proposed framework marginally outperforms all existing state-of-the-arts techniques on a range of different datasets.