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Search Results: 1 - 10 of 238222 matches for " Teng-Kai Chen;Gregory H. Huff "
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Modal Resistance of Spiral Antenna  [PDF]
Teng-Kai Chen, Gregory H. Huff
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2013, DOI: 10.4236/jemaa.2013.55036

This paper proposes a quasi-static conformal mapping analysis to analytically evaluate the input resistance of Archimedean spiral antenna at its radiation region. The deviation from the original constructs of band theory for two-wire spiral antennas leads to the concept of common slot-line mode radiation. The per-unit-length capacitance and the characteristic impedance of the quasi-TEM fundamental propagating mode in periodic coplanar waveguide (PCPW) structure are obtained in terms of spiral parameters including substrate properties. This formula enables little computational effort on the computation of input resistance at the radiation mode of balanced-excited two-arm Archimedean spiral antennas. The numerical simulation demonstrates the accuracy of derived formulas both in free space and when a dielectric layer is presented.

Analytical Investigation of Periodic Coplanar Waveguides
Teng-Kai Chen;Gregory H. Huff
PIER M , 2013,
Abstract: This paper presents an analytical formula to evaluate even- and odd-mode characteristics of infinitely parallel coplanar waveguides (CPW) with the same dimensions in each CPW, given name as periodic coplanar waveguides (PCPW). The analysis yields a closed-form expression based on the quasi-TEM assumption and conformal mapping transformation. Calculated results show that both the even- and odd-mode characteristic impedances are in good agreements with the results generated by numerical solvers and available experimental data. The results are important especially for highly demand on miniaturization of circuit design to place multiple CPWs in parallel.
Reconfigurable Antennas, Preemptive Switching and Virtual Channel Management
Santhosh Kumar,Jean-Francois Chamberland,Gregory H. Huff
Mathematics , 2012, DOI: 10.1109/TCOMM.2014.020514.130592
Abstract: This article considers the performance of wireless communication systems that utilize reconfigurable or pattern-dynamic antennas. The focus is on finite-state channels with memory and performance is assessed in terms of real-time behavior. In a wireless setting, when a slow fading channel enters a deep fade, the corresponding communication system faces the threat of successive decoding failures at the destination. Under such circumstances, rapidly getting out of deep fades becomes a priority. Recent advances in fast reconfigurable antennas provide new means to alter the statistical profile of fading channels and thereby reduce the probability of prolonged fades. Fast reconfigurable antennas are therefore poised to improve overall performance, especially for delay-sensitive traffic in slow-fading environments. This potential for enhanced performance motivates this study of the temporal behavior of point-to-point communication systems with reconfigurable antennas. Specifically, agile wireless communication schemes over erasure channels are analyzed; situations where using reconfigurable antennas yield substantial performance gains in terms of throughput and average delay are identified. Scenarios where only partial state information is available at the receiver are also examined, naturally leading to partially observable decision processes.
Performance Characteristics of SALiM Isolator
H. Teng,Q. Chen
Lecture Notes in Engineering and Computer Science , 2009,
Fluoroscopic Placement of Double-Pigtail Ureteral Stents
Gregory L. Chen,Demetrius H. Bagley
Diagnostic and Therapeutic Endoscopy , 2001, DOI: 10.1155/dte.7.175
Abstract: Purpose: Double-pigtail ureteral stent is placed cystoscopically after ureteroscopy. We describe a technique for fluoroscopic placement of ureteral stents and demonstrate its use in a non-randomized prospective study.
Long-term survival in a patient with repeated resections for lung metastasis after hepatectomy for ruptured hepatocellular carcinoma: a case report
Kai-Lun Shih, Yang-Yuan Chen, Tsung-Han Teng, Maw-Soan Soon
Journal of Medical Case Reports , 2008, DOI: 10.1186/1752-1947-2-222
Abstract: Here we report a 50-year-old man with survival of over 90 months after undergoing an extended right lobectomy for a ruptured hepatocellular carcinoma and then repeated resections for pulmonary metastasis during the followup period.This case report shows that surgical resection can be an effective treatment for patients with both ruptured hepatocellular carcinoma and pulmonary recurrences.Hepatocellular carcinoma (HCC) is the most common primary hepatic tumor and one of the most common cancers worldwide. Spontaneous rupture is a life-threatening complication of HCC. The overall incidence of spontaneous rupture of HCC varies from 5% to 26%, with a mortality rate of up to 67%, especially in patients with poor liver function [1-4].The treatment of a ruptured HCC is controversial. Previous studies have suggested that emergency liver resection is feasible in patients with a small tumor and satisfactory liver function (Child-Pugh A or B grade). Surgical resection is currently the only way to achieve long-term survival [5].The lung is the most common site of metastasis in patients with HCC. These are often unresectable as most pulmonary metastases are multiple [6]. Nevertheless, some studies have revealed that surgical resection of pulmonary metastases from HCC may prolong survival in selected patients [7-9]. Ruptured HCC often exacerbates the risk of disseminated intraperitoneal metastases, and previous studies have suggested long-term survival may be possible with aggressive surgical treatment, even if intraperitoneal metastases develop [10,11]. However, to our knowledge there has been no report of a patient who has undergone resections of pulmonary metastasis after hepatectomy for a ruptured HCC. Here we report a rare case of long-term survival after three pulmonary metastasectomies following hepatectomy for a ruptured HCC.On 23 February 2000, a 50-year-old man was referred to our hospital because of progressive abdominal pain for 3 hours. The patient's initial blood pre
Test Study on Navigation in the First Construction Period of Lize Navigation-Power Junction  [PDF]
Kai Chen
Engineering (ENG) , 2016, DOI: 10.4236/eng.2016.86030
Abstract: Based on the test results of Lize navigation-power junction construction diversion through the normal fix-bed model with the scale of 1:100, the navigation flow condition in each construction diversion period is studied. There are a lot of problems in the first construction diversion period, such as excessive flow velocity, poor flow pattern, low navigation discharge and so on. To solve these problems, the comprehensive engineering measures for improving the navigation flow condition during construction are put forward. Among them, the structure forms of construction diversion cofferdam are optimized. Finally, the highest safe navigation discharge and reasonable navigation route are proposed. The experimental results obtained from the optimization scheme of the first construction diversion period are better than these from the original scheme in terms of flow velocity, flow pattern and so on. The research results may serve as reference for similar engineering.
Biosynthesis of a Fluorescent Cyanobacterial Phycoerythrocyanin Holo-α Subunit in Escherichia coli

TENG Yin,ZHOU Ming,CHEN Fang,ZHAO Kai-Hong,

植物科学学报 , 2006,
Abstract: 为了研究藻红蓝蛋白α亚基的生物合成途径,通过构建相容的4种重组质粒pETDuetp-ecA、pCOLADuet-pecE、pCDFDuetp-ecF和pACYCDuet-ho1-pcyA,将裂合酶基因pecE和pecF、血红素氧化酶基因ho1、藻蓝胆素合成酶基因pcyA和脱辅基藻红蓝蛋白α亚基基因pecA共同转入大肠杆菌BL21(DE3),通过色素蛋白锌电泳和光谱检测表明产生了生物活性的PecA-PCB。结果表明生成的色素藻胆蛋白具有藻红蓝蛋白α-亚基所特有的光谱性质和可逆光致变色性质。而在裂合酶基因pecE和pecF不转入大肠杆菌的情况下,大肠杆菌内只有0.1%的PecA-PCB产生。以上研究对藻胆蛋白生物构建具有重要意义。
Impact of Thickness of Columnar Crystal TiO2 Film on Photocatalytic Activity of FTO/TiO2 Coated Glass
TENG Fan, LIU Yong, GE Yan-Kai, ZHANG Rui-Shuo, SONG Chen-Lu, HAN Gao-Rong
无机材料学报 , 2012, DOI: 10.3724/sp.j.1077.2012.00633
Abstract: Columnar crystal structured TiO2 thin films were prepared on the FTO (SnO2: F) low―emissivity coated glass substrates, obtaining double―layer structure FTO/TiO2 coated glass samples. The effect of TiO2 film thickness on the photocatalytic activity, the low―emissivity performance and light transmission properties of the FTO/TiO2 coated glass samples was investigated. The results showed that the photocatalytic activity of the samples increased firstly and then decrease with the increase of the film thickness. The best catalytic activity was observed for the sample coated with 300 nm TiO2 film. The low―emissivity properties of the samples declined as the TiO2 film thickness increased. The sample still have some low―emissivity performance when the TiO2 film thickness is 300 nm, while the light transmittance of the samples have little relations with the TiO2 films thickness. The visible light transmittances of the samples remain at about 72% with a smooth surface. The average surface roughness of the sample is about 1 nm. The FTO/TiO2 coated glass has photocatalytic self―cleaning properties with excellent low emissive performance and light transmittance property, thus guaranteeing good application prospects.
Location Identification of Power Line Outages Using PMU Measurements with Bad Data
Wen-Tai Li,Chao-Kai Wen,Jung-Chieh Chen,Kai-Kit Wong,Jen-Hao Teng,Chau Yuen
Computer Science , 2015,
Abstract: The use of phasor angle measurements provided by phasor measurement units (PMUs) in fault detection is regarded as a promising method in identifying locations of power line outages. However, communication errors or system malfunctions may introduce errors to the measurements and thus yield bad data. Most of the existing methods on line outage identification fail to consider such error. This paper develops a framework for identifying multiple power line outages based on the PMUs' measurements in the presence of bad data. In particular, we design an algorithm to identify locations of line outage and recover the faulty measurements simultaneously. The proposed algorithm does not require any prior information on the number of line outages and the noise variance. Case studies carried out on test systems of different sizes validate the effectiveness and efficiency of the proposed approach.
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