WLAN chip antenna mountable above the system ground plane of a mobile device

A novel wireless local-area network (WLAN) chip antenna suitable to be mounted above the system ground plane of a mobile device is presented. The antenna in the study is easily fabricated from folding a single metal plate onto a foam base, and mainly comprises a short-circuited radiating strip and an antenna ground. The antenna ground occupies the bottom surface and two adjacent side surfaces of the foam base. When the antenna is mounted at the corner of the system ground plane, this antenna ground structure is expected to effectively reduce the antenna's possible fringing electromagnetic fields inside the mobile device. In this case, when the associated element such as the radio-frequency shielding metal case is placed under the proposed antenna, small or negligible variations in the antenna performance are obtained. Design considerations of the proposed antenna for WLAN operation in the 2.4 GHz band are described, and results of the constructed prototypes are presented.     

Surface-mount dual-loop antenna for 2.4/5 GHz WLAN operation

A surface-mount dual-loop antenna suitable for dual-frequency WLAN operation is presented. For achieving dual-frequency operation with a compact size, the antenna comprises two loop strips of different sizes printed on a flexible printed circuit board, which is then bent and attached onto a foam base of compact size. The antenna shows an attractive feature of high antenna gain, about 4 and 5 dBi for frequencies across the 2.4 and 5 GHz WLAN bands, respectively.     

脉冲电镀最佳参数之探索和优化

本文利用正交实验法对脉冲电镀各控制参数进行试验,对影响分散能力、镀层可靠性及外观质量的各种因素进行探讨,寻找影响外观质量的显著因子并加以控制,同时进一步优化脉冲电镀的工艺参数。     

Hydrogenated amorphous silicon thin-film transistor arrays fabricated by digital lithography

A jet-printed digital-lithographic method, in place of conventional photolithography, was used to fabricate 64 /spl times/ 64 pixel (300 /spl mu/m pitch) matrix addressing thin-film transistor (TFT) arrays. The average hydrogenated amorphous silicon TFT device within an array had a threshold voltage of /spl sim/3.5 V, carrier mobility of 0.7 cm/sup 2//V/spl middot/s, subthreshold slope of 0.76 V/decade, and an on/off ratio of 10/sup 8/.     

Integrated magnetic full wave converter with flexible output inductor

A new integrated magnetic full wave DC/DC power converter that provides flexible transformer design by incorporating an independent output inductor winding is introduced. The transformer is implemented on a traditional three-leg magnetic core. The inductor winding can be separately designed to control the output current ripple. The cross-sectional area of the inductor core leg can be reduced dramatically. The operation and performance of the proposed circuit are verified on a 100 W prototype converter.     

On teletraffic applications to OBS

We provide teletraffic models for loss probability evaluation of optical burst switching (OBS). We show that the popular Engset formula is not exact for OBS modeling and demonstrate that in certain cases it is not appropriate. A new exact model is provided. The various models are compared using numerical results for various OBS alternatives with and without burst segmentation.     

Pile Response Adjacent to Braced Excavation

The excavation of soil for the construction of basements or cut-and-cover tunnels results in ground movements. One particular concern is that the excavation-induced lateral soil movements may adversely affect any nearby pile foundation. The lateral loads imposed by the soil movements induce bending moments and deflections in the pile, which may lead to structural distress and failure. This paper presents the results of an actual full-scale instrumented study that was carried to examine the behavior of an existing pile due to nearby excavation activities resulting from the construction of a 16 m deep cut-and-cover tunnel. The pile was located 3 m behind a 0.8 m thick diaphragm wall. Excavation to the formation level that was 16 m below the ground surface resulted in a maximum lateral pile movement of 28 mm. A simplified numerical procedure based on the finite-element method was used to analyze the pile response. Generally, the theoretical predictions were in reasonable agreement with the measured results.     

Orientation-based unique representation for planar curves and shapes

This paper presents an orientation-based representation for planar curves and shapes. The new representation can uniquely represent all types, of planar shapes, be it convex, nonconvex, polygonal, smoothly curved, or piecewise smooth shapes. It is based on a new parameterization, theabsolute integral orientation. This representation is invariant under translation and rotation. The absolute integral orientation is a parameter invariant under scaling. As a result, matching of similar shapes (i.e., determination of the relative orientation and the scaling factor) using the absolute integral orientation as the parameter is easier than using the arclength as the parameter. In addition, the new representation has the feature of adaptive sampling, making it more compact and efficient than arc-length-based representations.     

含钡合金在钢液中的脱氧行为研究

在MoSi2炉上采用MgO质坩蜗对钢管进行了含钡合金脱氧行为的研究。实验中钡系合金主要选取SiAUBa、SiCaBa、SiAlBaCa、SiAlBeCaSr及用于钙处理的SiCa包芯线，选用Al作为对比脱氧剂，考察了钡系合金脱氧的全氧含量，脱氧产物的分布、尺寸和形貌，探讨了钡系合金脱氧和对夹杂物变性作用的机理。     

随机模拟在电信网性能评价中的应用

本文介绍了可在微机上实现大规模电信网践模拟的实用化软件ＳＩＭＵＮＥＴ，及基所采用的无时钟事件追踪法。该软件可用规划中的电信网络和实际网路的模拟及性能评价，也可用于不同流量控制算法的评价。文中给出一个评价实例。