• Title/Summary/Keyword: Lee Sam

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A Study on the Bandwidth Enhancement of a Microstrip Surface Wave Antenna With a Monopole Like Pattern (모노폴 방사패턴을 가지는 마이크로스트립 표면파 안테나의 대역폭개선에 관한 연구)

  • Jang, Jae-Sam;Jung, Young-Ho;Lee, Ho-Sang;Jo, Dong-Ki;Park, Seong-Bae;Kim, Cheol-Bok;Lee, Mun-Soo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.12
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    • pp.139-145
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    • 2008
  • In this paper, a microstrip surface wave antenna(SWA) with a frequency selective surface structure(FSS) is designed and measured. A microstrip SWA has many advantages such as low profile, low weight, easy fabrication, and compatibility with monolithic microwave integrated circuits(MMIC). In addition, it has demonstrated monopole like beam patterns. The microstrip SWA consists of two parts : a center-fed modified microstrip patch to excite surface wave, and a periodic patches to support the propagation of the surface waves. To obtain wide bandwidth, the ring type parasitic element is inserted and the circular patch is selected for the unit element in FSS structure. Experimental results show that the microstrip SWA has monopole like beam patterns at 5.9GHz. Impedance bandwidth and gain is 12% and 5.6dBi.

Design of a U-Type Planar UWB Antenna Composed of Monopole Pair (모노폴 쌍으로 구성된 U자형 평면 UWB 안테나 설계)

  • Lee, Ho-Sang;Jang, Jae-Sam;Jung, Young-Ho;Kim, Cheol-Bok;Kim, Jae-Hoon;Park, Seung-Bae;Lee, Mun-Soo
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.9
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    • pp.60-66
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    • 2008
  • In this paper, the CPW-fed Ultra-wideband antenna is designed and fabricated for UWB communications. To achieve ultra-wide bandwidth of the antenna, we propose the mutual coupling of two planar monopole antennas. The mutual coupling of monopole pair of the proposed antenna is optimized by adjusting the parameters, the widths of the planar monopoles and the space between two monopoles. Two UWB antennas with different horizontal sections of the CPW-fed monopole antenna are fabricated and measured to examine the mutual coupling effects on the monopole pair antenna. The measured result show that two antennas are satisfied with UWB communication band(3.1$\sim$10.6Ghz).

A Case of Trousseau's Syndrome Associated with Lung Cancer (폐암과 동반된 Trousseau 증후군 1예)

  • Song, Min-Kyung;Kim, Young-Sam;Lee, Kee-Myung;Kim, Se-Kyu;Chang, Joon;Kim, Sung-Kyu;Lee, Won-Young
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.6
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    • pp.941-946
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    • 1995
  • The association between hypercoagulability and malignant disease was first described by Armand Trousseau in 1865. According to Trousseau, the thrombophlebitis was usually/migratory and recurrent and involved both venous and arterial system. Thrombosis remains the hallmark of Trousseau's syndrome, although a wide variety of coagulation disorders including disseminated intravascular coagulation(DIC), pulmonary embolism, thrombotic endocarditis, and bleeding have been associated with the syndrome. Since then, abnormalities of the coagulation system have been repeatedly demonstrated in patients with cancer. Pancreatic carcinoma is thought to carry the highest risk of Trousseau's syndrome although the number of cases of Trousseau's syndrome is actually higher in patients with lung cancer because of the greater prevalence of this tumor. We report a thirty-five year old male patient with Trousseau's syndrome associated with lung cancer initially presenting deep vein thrombosis.

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Diffuse Reticular Interstitial Infiltrations in the Patient with Worsening Exertional Dyspnea after Clomifen Hormonal Therapy (Clomifen 호르몬제 복용후 호흡곤란이 악화된 환자에서의 미만성 망상형 간질성 폐침윤)

  • Park, Hyeong-Cheon;Kim, Young-Sam;Kim, Se-Kyu;Chung, Kyung-Young;Shin, Dong-Hwan;Lee, Hong-Lyeol;Chang, Joon;Kim, Sung-Kyu;Lee, Won-Young
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.4
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    • pp.624-628
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    • 1995
  • Lymphangioleiomyomatosis is a rare disease which afflicts young women of childbearing age. We experienced a 32-year-old female who was admitted because of worsening exertional dyspnea after hormonal therapy with Clomifen for five months and intermittent hemoptysis. Chest PA showed diffuse ground glass appearance with some reticular infiltrations. High resolution CT scan showed multiple small thin walled cysts distributed homogeneously throughout the entire lung. Pulmonary function test showed characteristic obstructive pattern despite the restrictive interstitial pattern of chest radiography. Thoracoscopic lung biopsy specimen showed abnormal proliferation of smooth muscle cells in the walls of lymphatic vessels, bronchioles, and pulmonary vessels typical of pulmonary lymphangioleiomyomatosis. Hormonal therapy with medroxyprogesterone was initiated.

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A Study on the Monitoring and Evaluation of Priority Projects for Urban Regeneration (도시재생사업의 모니터링 및 평가방안 연구: 선도지역을 사례로)

  • Kim, Ryoon-Hee;Lee, Jong-Gun;Lee, Sam-Su
    • Land and Housing Review
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    • v.6 no.1
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    • pp.1-9
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    • 2015
  • This study is significant by suggesting the plan of urban regeneration strategy, selection of vitalization area and build basic DB for establishing a plan of urban regeneration vitalization and draw measures to evaluate and monitor as urban regeneration project is promoted in earnest. For the process of study, basic DB and evaluation monitoring index were examined based on collaboration proposal of 13 leading areas and (the agenda of) the plan of urban regeneration vitalization in 4 areas(Seoul, Changwon, Busan, Yeongju). This study can be concluded as follows; First, general information system which can support regeneration strategy vitalization plans for smooth promotion of the project and manage regeneration vitalization project and all kinds of city maintenance projects systematically are necessary. Second, monitoring of regeneration project should be firstly institutionalized. thrid, it's necessary to secure that city or county foundational management plan and the relations during the establishment of strategic vitalization plan. Finally, it's necessary to introduce and evaluate modularized plan suitable for Bottom-up regeneration project.

Supercritical water oxidation of Dimethyl methylphosphonate(DMMP) (Dimethyl methylphosphonate(DMMP)의 초임계수 산화반응)

  • Lee, Hae-Wan;Ryu, Sam-Gon;Lee, Jong-Chol;Hong, Deasik
    • Korean Chemical Engineering Research
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    • v.44 no.6
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    • pp.636-643
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    • 2006
  • Supercritical water oxidation of DMMP using continuous flow reactor was studied at temperature ranging from 440 to $540^{\circ}C$ and a fixed pressure of 242 bar. The range of residence times in the reactor was from 10 to 26 s, and oxygen excess value varied from -40 to 200%. Destruction efficiencies (DE) of DMMP were greater than 99.7% at $540^{\circ}C$, and increased as the DMMP concentrations were increased. DE of DMMP were significantly affected by oxygen concentration under stoichiometric amount, but showed little difference over stoichiometric amount. On the basis of 30 data with conversions greater than 85%, kinetic correlations for the DE of DMMP were developed. The pre-exponential factor was $(1.10{\pm}0.76){\times}10^6$, and the activation energy was $90.66{\pm}3.87kJ/mol$, and the reaction orders for DMMP and oxygen were $1.02{\pm}0.03$, $0.32{\pm}0.03$, respectively. The model predictions agreed well with the experimental data.

Catechin and Caffeine Concentration Variations in Jeju Green Tea Varieties Harvested Over a Seven-Month Period

  • Song, Kwan-Jeong;Beak, Dong-Chul;Kim, You-Wang;Kim, Young-Geol;Lee, Min-Seok;Lee, Sam-Pin;Kim, Chan-Shick
    • Preventive Nutrition and Food Science
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    • v.15 no.3
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    • pp.229-232
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    • 2010
  • Caffeine and catechins from the Yabukita, Yutakamidori, Saemidori, Okumidori, and Fushun varieties of tea leaves picked during different harvesting seasons from April to October were evaluated using HPLC. Total content of catechins increased greatly with the later harvesting time of tea leaves (i.e., picking the leaves in September versus in April) and decreased slightly after September. Yabukita tea leaves picked in August contained 43.1 mg% catechins including EGC, EC, ECG, and EGCG, with the ECGC levels constituting greater than 50% of those four compounds. Yutakamidori and Okumidori varieties picked in September contained the highest catechin values, at 43.6 mg% and 31.0 mg%, respectively. Fushun and Saemidori varieties contained lower catechin concentrations of 14.5 mg% (July) and 11.7 mg% (August) compared to other varieties. The EGCG levels gradually decreased in the late harvesting season, while levels of the other catechins, EC, EGC, and ECG, gradually increased. All varieties of green tea showed a gradual decrease in caffeine content toward the end of our harvesting efforts in October, with levels of 58~68 mg% in April and 28~57 mg% in October. Yabukita, Saemidori, and Okumidori varieties reached their highest caffeine levels in late spring/early summer, with Yabukita and Okumidori varieties reaching a high of 73.4% and 63.5% caffeine, respectively, in May, and Saemidori at 64.0% in June. In particular, Fushun still contained high caffeine of 66.8 mg% (September) during the late harvesting season.

Analysis of Influencing Factors on Self-perceived Health Status of Labors in Workplace (산업장 근로자의 주관적 건강인식에 영향을 미치는 요인 분석)

  • Lee Jeong-Han;Ko Youn-Seok;Kwon So-Hee;Kim Sam-Tae;Jung Hae-Kyoung;Park Seung-Jong;Song Yung-Sun;Lee Ki-Nam
    • Journal of Society of Preventive Korean Medicine
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    • v.8 no.1
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    • pp.135-145
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    • 2004
  • This study tried to analyze influencing factors on self-perceived health status(SPHS) of labors in workplace. and suggested the preventive oriental medicine approaches in occupational health care. 914 data for research were collected through the process of oriental health examination with questionnaire in workplace and collected data were analyzed with frequency, homogeneity and correlation statistically. The results were as follows : 1) The distributions of SPHS was 58.4% of healthy group. 41.6% of unhealthy group. 2) For the difference of SPHS by stress, the high level stress group was more included in healthy group(p<0.05). 3. For the difference of SPHS by health behavior. the higher score of health behavior group was more included in healthy group. There was statistically significant difference of SPHS in physical exercise, but not in smoking, drinking, sleeping and body mass index. 4. For the difference of SPHS by the latest health examination results, non-disease group was more included in healthy group, while disease group was more included in unhealthy group. From the above results, SPHS was influenced by stress, health behavior, the latest health examination results. Therefore oriental medical service for occupational health must be interested in the these influencing factors and make an effort to change their perception of health as well as physical improvement.

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A Study on the Characteristics of Heart Rate Variabilities In Nornal Subjects and Hemiplegic patients (정상인과 편마비 환자의 심박변동신호의 특성에 관한 연구)

  • Jeong, Kee-Sam;Shin, Kun-Soo;Lee, Jeong-Whan;Ahn, Juhn;Chon, Joong-Son;Kim, Jun-Soo;Lee, Myoung-Ho
    • Journal of Biomedical Engineering Research
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    • v.18 no.3
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    • pp.285-290
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    • 1997
  • In this paper, the power spectral analysis and the fractal analysis of heart rate variability(HRV) were performed to evaluate the effects of brain lesion on cardiovascular system and autonomic function for 24 normal subjects and 22 hemiplegic patients. The ECG and respiration signals were recorded at tilt angles of $0^{\circ}$ and $70^{\circ}$ for 5 and 6 minutes successively under the condition of frequency controlled respiration (0.25Hz). For normal subjects, HR, LF component, HF component and fractral dimension of HRV were distinctly changed after orthostatic stress, whereas, for hemiplegic patients, those were little changed. Complexity and variability of heart rate of patients were smaller than those of normal subjects. Sympathetic tone of patients was higher than that in normal subjects. All of these results support that autonomic disorder and cardiovascular disturbance accompanied by brain lesion could be assessed by the power spectral analysis and fractal analysis of HRV.

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End-fitting Design and Performance Evaluation of Polymer Insulator (폴리머 애자의 End-fitting 설계 및 성능 평가기술)

  • Cho, H.G.;Lee, U.Y.;Han, S.W.;Han, D.H.;Ji, W.Y.;Yeo, H.G.;Kang, D.W.;Chun, J.U.;Lee, H.K.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.05b
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    • pp.25-29
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    • 2004
  • Corona on polymer materials causes deterioration by the combined action of the discharge striking the surface and the action of certain chemical compounds that are formed by the discharges. In the design and manufacture of polymer insulators must be sufficiently large to avoid corona discharges, otherwise a shielding or corona ring (grading ring) needs to be installed on the insulator. To conduct this purpose, many researchers have investigated end-fitting of polymer insulator by voltage distribution simulation and electrical test. Grading rings are used to improve the performance of the insulator in multiple ways. They can reduce corona and associated audible noise and radio influence and television interference. The factors determining the uses of a grading ring are line voltage, geometry and dimensions of end fittings, geometry and dimensions of line hardware, and environmental conditions. In this paper, electrical property of polymer insulator with end-fitting design have been investigated by electrical field analysis, various end-fitting design, tracking wheel test, corona inception voltage and extinction voltage. Electrical field analysis is conducted by FEM program and various end-fitting is designed through this result. Designed end-fittings are manufactured and their performance is conducted by electrical performance test.

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