• Title/Summary/Keyword: full body type

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Numerical Analysis of Optical Damage in Dielectrics Irradiated by Ultra-Short Pulsed Lasers (극초단 펄스 레이저에 의한 절연체의 광학 손상 해석)

  • Lee, Seong-Hyuk;Kang, Kwang-Gu;Lee, Joon-Sik;Choi, Young-Ki;Park, Seung-Ho;Ryou, Hong-Sun
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1213-1218
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    • 2004
  • The present article reports extensive numerical results on the non-local characteristics of ultra-short pulsed laser-induced breakdowns of fused silica ($SiO_{2}$) by using the multivariate Fokker-Planck equation. The nonlocal type of multivariate Fokker-Planck equation is modeled on the basis of the Boltzmann transport formalism to describe the ultra-short pulsed laser-induced damage phenomena in the energy-position space, together with avalanche ionization, three-body recombination, and multiphoton ionization. Effects of electron avalanche, recombination, and multiphoton ionization on the electronic transport are examined. From the results, it is observed that the recombination becomes prominent and contributes to reduce substantially the rate of increase in electron number density when the electron density exceeds a certain threshold. With very intense laser irradiation, a strong absorption of laser energy takes place and an initially transparent solid is converted to a metallic state, well known as laser-induced breakdown. It is also found that full ionization is provided at intensities above threshold, all further laser energy is deposited within a thin skin depth.

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Experimental and numerical studies on VIV characteristics of π-shaped composite deck of a cable-stayed bridge with 650 m main span

  • Wei Lei;Qi Wang;Haili Liao;Chengkai Shao
    • Wind and Structures
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    • v.38 no.2
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    • pp.93-107
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    • 2024
  • A π-shaped composite deck in the form of an open section is a type of blunt body that is highly susceptible to wind loads. To investigate its vortex-induced vibration (VIV) performance, a large-scale (1/20) section model of a cable-stayed bridge with a main span of 650 m was tested in a wind tunnel. The vibration suppression mechanism of the countermeasures was analyzed using computational fluid dynamic. Experimental results demonstrate that the vertical and torsional VIVs of the original section can be suppressed by combining guide plates with a tilt angle of 35° and bottom central stabilizing plates as aerodynamic countermeasures. Numerical results indicate that the large-scale vortex under the deck separates into smaller vortices, resulting in the disappearance of the von Kármán vortex street in the wake zone because the countermeasures effectively suppress the VIVs. Furthermore, a full-bridge aeroelastic model with a scale of 1/100 was constructed and tested to evaluate the wind resistance performance and validate the effectiveness of the proposed countermeasures.

Study on the Performance of Laser Welded joint of Aluminum alloys for Car Body

  • Kutsuna, Muneharu;Kitamura, Shuhei;Shibata, Kimihiro;Salamoto, Hiroki;Tsushima, Kenji
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.620-625
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    • 2002
  • Considering the fuel consumption of car, a light structure of aluminum alloys is desired for car body nowadays. However, fusion welding of aluminum alloys has some problems of reduction of joint efficiency, porosity formation and hot cracking. ill the present work, investigation to improve the joint performance of laser welded joint has been carried out by addition of Cu, Ni, and Zr to A6N01 alloy welds. Aluminum alloy plate of 2.0mm in thickness with filler metal bar was welded by twin beam Nd:YAG laser facility (total power:5kW). The filler metals were prepared by changing the chemical compositions for adding the elements into the weld metal. Thirteen filler metal bars were prepared and pre-placed into the base metal before welding. Ar gas shielding with a flow rate of 10 l/min was used. The defocusing distance is kept at 0 mm. At travel speeds of 3 to 9 m/min and at laser power of 5kW (front beam 2kW rear beam 3kW), full penetration welds were obtained, whereas at travel speeds of 12 to 18 m/min and same power, partial penetration was observed. The joint efficiency of laser-welded joint was improved by the addition of Cu, Ni, and Zr due to the solid solution hardening, grain refining and precipitation hardening. The type of hardening has been further considered by metallurgical examination.

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Study on the Performance of Laser Welded Joint of Aluminum Alloys for Car Body

  • Kutsuna, M.;Kitamura, S.;Shibata, K.;Sakamoto, H.;Tsushima, K.
    • International Journal of Korean Welding Society
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    • v.2 no.2
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    • pp.26-31
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    • 2002
  • Considering the fuel consumption of car, a light structure of aluminum alloys is desired fer car body nowadays. However, fusion welding of aluminum alloys has some problems of reduction of joint efficiency, porosity formation and hot cracking. In the present work, investigation to improve the joint performance of laser welded joint has been carried out by addition of Cu, Ni, and Zr to A6NO 1 alloy welds. Aluminum alloy plate of 2.Omm in thickness with filler metal bar was welded by twin beam Nd: YAG laser facility (total power: 5kW). The filler metals were prepared by changing the chemical compositions for adding the elements into the weld metal. Thirteen filler metal bars were prepared and pre-placed into the base metal before welding. Ar gas shielding with a flow rate of 10 1/min was used. The defocusing distance is kept at 0 mm. At travel speeds off 3 to 9 and at laser power of 5kW (front beam 2kW rear beam 3kW), full penetration welds were obtained, whereas at travel speeds of 12 to 18 m/min and same power, partial penetration was observed. The joint efficiency of laser-welded joint was improved by the addition of Cu, Ni, and Zr due to the solid solution hardening, grain refining and precipitation hardening. The type of hardening has been further considered by metallurgical examination.

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Feasibility of Manufacturing Desk and Chair with Curved Veneer Lamination (단판 적층성형 학생용 책상.의자의 제조적성)

  • Suh, Jin-Suk;Park, Jong-Young;Han, Ki-Man
    • Journal of the Korea Furniture Society
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    • v.16 no.2 s.30
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    • pp.59-65
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    • 2005
  • As physical condition of students improves, there is a need to develop human body-friendly desk and chair for students. In this study, desks and chairs were manufactured with curved veneer lamination under high frequency heating and pressing, using ten wood species such as Japanese red pine, Korean pine, pitch pine, Japanese larch, yellow poplar, black locust, oak, radiata pine, beech, and birch. The performance of these products were evaluated. The results obtained were summarized as follows; With high frequency heating, the turned lamination of veneers with full size sheet ($3{\times}6\;feet$) prepared by rotary lathe peeling was successfully applied for making the members of desk top, leg frames of desk and chair. Bending strengths of desk tops were relatively greater for yellow poplar, black locust and red pine, which were similar to those of beech and birch. Bending strengths of desk legs were classified into greater species group (red pine, yellow poplar, larch) and lower species group (radiata pine, Korean pine, pitch pine). Compressive strengths of chair legs in parallel direction to the lamination were greater in black locust and larch. On the other hand, differences between outer and inner gap at the top and drawer bottom of desk top were rather larger for the laminations of birch and beech, and less for those of yellow poplar and pitch pine, showing greater stability of open drawer space. In results, yellow poplar, larch, pitch pine and red pine showed good appearance and strength properties at the curved veneer lamination. Accordingly, it was believed that these domestic woods were able to substitute for birch which was being imported for the use of veneer-laminates type furniture.

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The Development of a Battle Dress Uniform Pattern Improved functionality for the Korean police SWAT units - Focused on the Development and the Fitting Evaluation of the BDU - (경찰특공대(SWAT) 작전복(BDU)의 기능성 향상을 위한 패턴개발 - 작전복 개발 및 착의평가를 중심으로 -)

  • Moon yeon-Sil;Kim Son-Hee;Kim Eun-Kyong
    • Journal of the Korean Home Economics Association
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    • v.43 no.5 s.207
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    • pp.235-248
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    • 2005
  • The objective of the study was to design a Battle Dress Uniform(BDU with improved motional flexibility, body fit, and protectiveness to cope with the special operational environment of the subjects. For this purpose, the researcher conducted a questionnaire survey on 92 male members of Special Weapon Attack Team(SWAT units in a former study, and based on the results of the survey, made the two-piece and one- piece BDU samples to overcome the identified problems and inconveniences. The sample uniforms were designed ergonomically from five aspects. Subsequentlv, the new BDU was compared with the current operational uniform in terms of outward appearance(design and fit), motional flexibility, and suitability for field activities. The samples were evaluated by 5 SWAT members as subjects and 8 graduate school students majoring in clothing and textiles as experts. According to the results, the two-piece and one-piece samples gained higher scores than the existing operational uniform in terms of outward appearance(design and fitness) and motional flexibility, and the one-piece sample was preferred with regard to fit when worn by the subjects with their full kit for field operations. That is, the one-piece sample appeared to be more suited to the special work environment of SWAT and to be more functional in terms of ease of putting on and taking off, motional flexibility, body fit and protectiveness than the current operational uniform(two-piece type).

Experimental Analysis of Towing Attitude for I-type and Y-type Tail Fin of Active Towed SONAR (I 형 및 Y 형 꼬리 날개 능동 예인 음탐기의 예인 자세에 대한 실험적 분석)

  • Lee, Dong-Sup
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.8
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    • pp.579-585
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    • 2019
  • Increasing the detection probability of underwater targets necessitates securing the towing stability of the active towed SONAR. In this paper, to confirm the effects of tail wing fin on towing attitude and towing stability, two scale model experiments and one sea trials were conducted and the results were analyzed. The scale model tests measured the towing behavior of each of the tail fin shapes according to towing speed in a towing tank. The shape of the tail fin used in the scale model test was tested with an I-type tail fine and four Y-type tail fins, totaling five tail fins of the two kinds. The first scale model test confirmed that the Y-type tail fin was superior to the I-type tail fin in towing attitude and towing stability. The second scale model test confirmed the characteristics of the vertical tail fin height increase and the lower horizontal tail fin inclination angle application shape based on the Y-type tail fin. The shape of the application of the lower horizontal tail fin inclination angle showed the best performance. In order to verify the results of the scale model test, a full size model was constructed, sea trials were performed, and the towing attitude was measured. The results were similar to those of the scale model test.

The Study for Comparing between Theory about "Constitution" in Chinese Medicien and Sasang Constitutional Medicine in Korea (중국의 변질논치(辨質論治)이론과 한국 사상체질(四象體質)의학에서의 체질(體質)이론 비교연구)

  • Kim, Eun-Hee;Seo, Young-Kwang;Jung, Yee-Hong;Kim, Sun-Hyung;Lee, Soo-Kyung;Koh, Byung-Hee;Kim, Dal-Rae
    • Journal of Sasang Constitutional Medicine
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    • v.21 no.1
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    • pp.35-43
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    • 2009
  • 1. Objectives This study is for comparing between theory about "Constitution" in China and Sasang constitutional Medicine in Korea 2. Method I refered to the literatures about "Constitution" published in China and Korea 3. Result and Conclusion 1) "Constitution" in Traditional Chinese Medcine(TCM) is reinterpretation of Traditional Chinese Medcine, while, Constitution in Sasang Constitutional Medicine is an innovative concept developed from Traditional Korean Medicine. 2) The concept of "Constitution" in Chinese Medicien is related to long-term-period symptom or physical condition, while, the concept of Constitution in Sasang Constitutional Medicien includes not only long-term-period symptoms or physical conditions but also natural superiority and inferiority of individual according to 4 type Constitution. 3) The concept of Constitution in Sasang Constitutional Medicien has organized mind-body system than Concept of "Constitution" in Chinese Medicine. According to the theory of Sasang Constitutional Medicine, Mind is one of the best important things related type of disease. Lectures of Sasang Constitutional Medicine give a full detail of correlation of Mind and disease. 4) Finally, The concept of "Constitution" in Chinese Medicien is changeable but the Concept of "Constitution" in Sasang Constitutional Medicien is not changeable. changeable elements in Sasang Constitutional Medicien are symptoms and syndromes of disease.

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Relationships between Shift Work and Occupational Accidents in a Steel Company (철강회사에 있어서 교대작업과 산업재해의 관련성)

  • Seo, Yoo-Jin;Kazuya, Matsumoto;Moon, Se-Keun;Jung, Min-Sang;Kim, Myung-Il
    • Journal of the Korean Society of Safety
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    • v.20 no.3 s.71
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    • pp.188-196
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    • 2005
  • Accident reports from 1991 to 2000 of a steel company were used to analyze which factors induce industrial accidents. The subjects were 8,311 blue-collar workers, who sustained 114 occupational injuries and work on a continuous full-day 3-team 3-shift system of backward rotation(mornings to afternoons to nights). With respect to marital status, the occupational injury rate(OIR) on the married workers was significantly higher compared to unmarried workers. With respect to no, the OIR of those in their early 20s was significantly higher when compared to other age groups. The OIR of highly educated workers showed a reduction when compared with lower educated workers. The OIR of shift workers were significantly higher compared with the daytime workers. The OIR of type of work decreased across the steel manufacturing process, rolling process, machine maintenance section forwarding products section to the field management section. With respect to the block of shift work(morning, afternoon, and night shifts) by the type of work, the OIR of the night shift was higher than those of the morning shift in the steel manufacturing process or forwarding products section. The OIR of the machine maintenance section was slightly higher in the morning shift than those of the night shift. The OIR of the time of day of the shift workers reached a peak between 09:00 and 11:00. The OIR of a slight injury to shift workers decreased across the night, afternoon, to morning shifts whereas the OIR of a serious injury tended to decrease across the night, morning, to afternoon shift. The body parts most commonly injured were the arm and the crus.

Treatment of Skin Diseases in Hyungsang Medicine (피부병의 형상의학적 치료)

  • Suk Min He;Hwang Won Duek;Jung Haeng Gyu;Lee Yong Tae
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.18 no.3
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    • pp.646-669
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    • 2004
  • By treating skin diseases with Hyungsang medicine and reviewing the clinical cases of them through classifying skin diseases into general care and into Hyungsang medical care, the writer came to the conclusion as followings. The skin is a house of Kyungnak, and it' s a place which Ki comes in and out, which human body controls conditions of his physiological function and which doctors can make a diagnosis from seeing it. The skin is subject to lung and large intestine in the point of organ, but in the point of movement, to spleen and stomach. Skin diseases come from unbalance of Ki and Hyul, mostly from fever in blood and also from Dam, Wind, Dampness and Dryness because of including fire. Generally skin diseases are treated according to classifying into distinctive symptoms, region, cause or time being occurred, and concomitant symptoms. After being divided into man and woman, age and youth, fatness and leanness, Jung Ki Shin Hyul type, visceral figures, Yukkyung shapes on Hyungsang medicine method, the remedy of skin diseases which is combined common meditation with Hyungsang medical method is efficacious. In distinguishing into man and woman, age and youth, man gets sick mainly by drinking liquor and exhausting Jung, woman is taken ill generally by indigestion and Damwha, especially by drinking liquor. Young child gets ill mostly from inherent weakness, but in many cases he is occurred by disturbed digestion, so he must be taken care of ingesting food. The aged becomes ill from weakening, so he must be treated according to reasons of diseases. To fatness and leanness, skin diseases are showed symptoms by weakened Yang, insufficient Yin or excess fever on the theory of upper and lower parts, by unbalance of Ki and Hyul on the theory of left and right, by Dryness and Dampness on the theory of front and rear and by insufficiency of vitality and combined fever on the theory of inside and outside. Therefore doctors must cure the symptoms according to the theory of upper and lower, left and right, front and rear and inside and outside. In type of Jung Ki Shin Hyul, the balances between Jung-Hyul and Shin-Ki are important points. Concretely Jung type comes to easily shortage of Jung or gathering abnormally Dampness and Dam, Ki type is easy to make a mass with Ki or to be deficient of Ki, Shin type comes to press seven emotions togather or to be insufficient of Yin and fever inside, and Hyul type is inclined to be deficient of Hyul and to become feverish or to be deficient of Ki. Therefore on the ground of the above reasons skin diseases come into existence. Inclusively in Jung-Hyul type , Ki must be moved on the base of full Jung-Hyul, so Wukmijiwhangtang or Samultang is prescribed basically. In Shin-Ki type , Jung-Hyul is saved on the base of moving Ki, so Hyangsosan or Yijintang is the proper prescription. Considering the visceral figures, doctors judge for diagnosis and remedy by putting together the elements, that is, great and small sizes of a set of features (eye, ear, mouth, nose), color and temper. The yukkyung types are classified according to many or few of Ki-Hyul, and then skin diseases appear by being inclined toward one side between Ki and hyul, or among the six atmospheric elements(wind, cold, heat, dampness, dryness, and fire). Especially because Yangmyung type is full of much Ki and Hyul, and also has much fever in stomach, he gets skin symptoms frequently. So his prescription is based on taking off fever in stomach, and also he must be careful about regimen certainly.