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Development of heat exchanger for underground water heat. II - Design and manufacture for heat exchanger of underground water - (지하수 이용을 위한 열교환기 개발. II - 지하수이용 냉·난방기 설계제작 -)

  • Lee, W.Y.;Ahn, D.H.;Kim, S.C.;Park, W.P.;Kang, Y.G.;Kim, S.B.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.4 no.1
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    • pp.128-137
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    • 2002
  • This study was conducted to develop the heat exchanger by utilizing the heat energy of underground water(15℃), which might be used for cooling and heating system of the agricultural facilities. We developed the heat exchanger by using the parallel type plat fin tube made of Aluminum(Al 6063), which was named Aloo-Heat(No. 0247164, offered by Korean Intellectual property Office). The trial manufactures were made from Aloo-heat which was 600mm, 700mm length respectively, and It were welded to the end "U" type in order to direct flow of the underground water. The performance test was carried out under the condition of open space and room temperature with the change of flow rate of the underground water and air. The results are as follows. 1. The trial manufactures had convection heat value from 33 to 156 W/m2℃, and It was coincided with design assumption. 2. The amount of energy transfer was increased with the increment of the area of heat transfer, the air flow, the gap of temperature inlet & outlet the underground water and the air. 3. The heat value was 6,825W when the air flow was 6,000m3/h and the gap of temperature between inlet and outlet of the underground water was 6℃, and It dropped from 25.8℃ to 23.2℃(-2.6℃ difference). The convection heat value was 88.5W/m2℃. 4. The heat value was 2.625W when the air flow was 4,000m3/h and the gap of temperature between inlet and outlet the underground water was 2℃, and It dropped from 27℃ to 22.5℃(-4.5℃ difference). The convection heat value was 33.6W/m2℃. 5. Correlation values(R2) of the testing heat values of the trial manufacture type I, II, and III were 0.9141, 0.8935, and 0.9323 respectively, and correlation values(R2) of the amount of the air flow 6,000m3/h, 5,000m3/h, 4,000m3/h were 0.9513, 0.9414, and 0.9003 respectively.

Characteristics of Blood Mixed Cement in Percutaneous Vertebroplasty (경피적 척추 성형술에서 혈액 혼합 시멘트의 특성)

  • Seo, Jin-Hyeok;Woo, Young-Ha;Jeong, Ju-Seon;Kim, Do-Hun;Kim, Ok-Gul;Lee, Sang-Wook;Park, Chan-Ho
    • Journal of the Korean Orthopaedic Association
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    • v.54 no.5
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    • pp.435-439
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    • 2019
  • Purpose: This study evaluated the efficacy of blood mixed cement for osteoporotic vertebral compression fractures in reducing the complications of percutaneous vertebroplasty using conventional cement. Materials and Methods: This study was performed retrospectively in 80 patients, from January 2016 to January 2017. Porous cement was formed by mixing 2, 4, and 6 ml of blood with 20 g of cement used previously. A tube with a diameter and length of 2.8 mm and 215 mm, respectively, was used and the polymerization temperature, setting time, and optimal passing-time were measured and compared with those using only conventional cement. Radiologically, the results were evaluated and compared. Results: The polymerization temperature was 70.3℃, 55.3℃, 52.7℃, and 45.5℃ in the conventional cement (R), 2 ml (B2), 4 ml (B4), and 6 ml (B6), respectively, and the corresponding setting time decreased from 960 seconds (R) to 558 seconds (B2), 533 seconds (B4), and 500 seconds (B6). The optimal passing-time was 45 seconds (B2), 60 seconds (B4), and 78 seconds (B6) at 73 seconds (R), respectively and as the amount of blood increased, it was similar to the cement passing-time. The radiological results showed that the height restoration rates and the vertebral subsidence rates similar among the groups. Two cases of adjacent vertebral compression fractures in the R group and one in the B2 and B4 groups were encountered, and the leakage rate of the cement was approximately two times higher than that in the conventional cement group. Conclusion: In conventional percutaneous vertebroplasty, the procedure of using autologous blood with cement decreased the polymerization temperature, reduced the setting time, and the incidence of cement leakage was low. These properties may contribute to more favorable mechanical properties that can reduce the complications compared to conventional cements alone.

Modified Thoracoscopic Bullectomy (흉강경하 기낭절제술의 변형 술식)

  • Park, Chan-Beom;Cho, Min-Seob;Sa, Young-Jo;Lee, Jong-Ho;Jin, Ung;Kwon, Jong-Bum;Cho, Deog-Gon;Park, Kuhn;Cho, Kyu-Do;Kim, Chi-Kyeong
    • Journal of Chest Surgery
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    • v.36 no.12
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    • pp.937-942
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    • 2003
  • Morbidity, the use of analgesics, the amount of postoperative drainage and the postoperative hospital stay were reduced in VATS for pneumothorax. However, some authors preferred minithoracotomy to VATS because the rate of recurrence after VATS were between 5% and 10%. Therefore, we present a modified thoracoscopic bullectomy (MTB) which we believe has the advantages of conventional VATS and minithoracotomy. Material and Method: Sixty-six patients who received the operation from January 2002 to December 2002 were divided into 3 groups. Twenty-six patients were treated by axillary minithoracotomy and thirteen by conventional VATS and 18 by modified thoracoscopic bullectomy, The mean age was 21.9 years (range, 16∼35 years) for minithoracotomy group, 20.6 years (range, 17∼28 years) for conventional VATS group and 22.6 years (range, 16∼39 years) for MTB group. The mean follow-ups were 11.4 months for minithoracotomy group, 9.5 months for conventional VATS group and 4.7 months for MTB group. Result: The mean duration of operation was 55.79$\pm$23.35 minutes in MTB and 44.23$\pm$19.24 minutes in conventional VATS (p=0.333). The number of staplers being used was 1.63 $\pm$0.76 in MTB, 1.41$\pm$0.64 in minithoracotomy (p=0.663), and 2.92$\pm$1.19 in conventional VATS (p<0.001). The duration of indwelling chest tube was 1.63$\pm$0.76 day in MTB, 4.07$\pm$ 1.41 day in minithoracotomy (p<0.001) and 4.46$\pm$2.33day in conventional VATS (p<0.001). Hospital length of stay was 3.26$\pm$0.81 day in MTB, 6.04$\pm$2.21 day in minithoracotomy (p<0.001) and 6.69$\pm$3.33 day in conventional VATS (p<0.001). The number of postoperative complication and recurrence were 2 in minithoracotomy (7.4%), 5 in conventional VATS (38.5%) and 1 in MTB (5.6%). Conclusion: Modified thoracoscopic bullectomy is an effective procedure in the treatment of spontaneous pneumothorax.

A Study on the Consideration of the Locations of Gyeongju Oksan Gugok and Landscape Interpretation - Focusing on the Arbor of Lee, Jung-Eom's "Oksan Gugok" - (경주 옥산구곡(玉山九曲)의 위치비정과 경관해석 연구 - 이정엄의 「옥산구곡가」를 중심으로 -)

  • Peng, Hong-Xu;Kang, Tai-Ho
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.36 no.3
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    • pp.26-36
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    • 2018
  • This study aims to examine the characteristics of landscape through the analysis of location and the landscape of Gugok while also conducting the empirical study through the literature review, field study, and digital analysis of the Okgung Gugok. Oksan Gugok is a set of songs set in Ogsan Creek(玉山川)or Jagyese Creek(紫溪川, 紫玉山), which flows in front of the Oksan Memorial Hall(李彦迪), which is dedicated to the Lee Eong-jeok (李彦迪). We first ascertained the location and configuration of Oksan Gogok. Second, we confirmed the accurate location of Oksan Gogok by utilizing the digital topographic map of Oksan Gogok which was submitted by Google Earth Pro and Geographic Information Center as well as the length of the longitude of the gravel measured by the Trimble Juno SB GPS. Through the study of the literature and the field investigation, The results of the study are as follows. First, Yi Eonjeok was not a direct composer of Oksan Gugok, nor did he produce "Oksan Gugokha(Music)". Lee Ia-sung(李野淳), the ninth Youngest Son of Tweo-Kye, Hwang Lee, visited the "Oksan Gugokha" in the spring of 1823(Sunjo 23), which was the 270th years after the reign of Yi Eonjeok. At this time, receiving the proposal of Ian Sung, Lee Jung-eom(李鼎儼), Lee Jung-gi(李鼎基), and Lee Jung-byeong(李鼎秉), the descendants of Ian Sung set up a song and created Oksan Gugok Music. And the Essay of Oksan Travel Companions writted by Lee Jung-gi turns out being a crucial data to describe the situation when setting up the Ok-San Gugok. Second, In the majority of cases, Gogok Forest is a forest managed by a Confucian Scholar, not run by ordinary people. The creation of "Oksan Bugok Music" can be regarded as an expression of pride that the descendants of Yi Eonjeok and Lee Hwang, and next generation of several Confucian scholars had inherited traditional Neo-Confucian. Third, Lee Jung-eom's "Oksan Donghaengki" contains a detailed description of the "Oksan Gugokha" process and the process of creating a song. Fourth, We examined the location of one to nine Oksan songs again. In particular, eight songs and nine songs were located at irregular intervals, and eight songs were identified as $36^{\circ}01^{\prime}08.60^{{\prime}{\prime}}N$, $129^{\circ}09^{\prime}31.20^{{\prime}{\prime}}E$. Referring to the ancient kingdom of Taojam, the nine-stringed Sainam was unbiased as a lower rock where the two valleys of the East West congregate. The location was estimated at $36^{\circ}01^{\prime}19.79^{{\prime}{\prime}}N$, $129^{\circ}09^{\prime}30.26^{{\prime}{\prime}}E$. Fifth, The landscape elements and landscapes presented in Lee Jung-eom's "Oksan Gugokha" were divided into form, semantic and climatic elements. As a result, Lee Jung-eom's Cho Young-gwan was able to see the ideal of mountain water and the feeling of being idle in nature as well as the sense of freedom. Sixth, After examining the appearance of the elements and the frequency of the appearance of the landscape, 'water' and 'mountain' were the absolute factors that emphasized the original curved environment at the mouth of Lee Jung-eom. Therefore, there was gugokga can gauge the fresh ideas(神仙思想)and retreat ever(隱居思想). This inherent harmony between the landscape as well as through the mulah any ideas that one with nature and meditation, Confucian tube.