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상수원수 수질변화에 따른 전오존 처리효과 및 경제성 평가
최동훈 ( Dong Hoon Choi ),박진식 ( Jin Sik Park ),문추연 ( Choo Yeun Moon ),이재용 ( Jae Yong Lee ),유동춘 ( Dong Choon Ryu ),장성호 ( Seong Ho Jang ),권기원 ( Ki Won Kwon ),이수애 ( Soo Ae Lee ) 한국환경과학회 2013 한국환경과학회지 Vol.22 No.4
This study, changes in raw water quality is to indicate on the efficiency of ozone treatment of each pollutant as compared to derive the appropriate operating measures. The appropriate selection for injection rate of pre-ozone and did not inject pre-ozone assess changes in the water. When good water quality, you not injected of pre-ozone to evaluate the economic efficiency of electricity and put the most cost-effective ozone concentration were evaluated. Evaluation remove organic matter and chlorophyll-a concentration level in experiments with each factor of the water DOC> 2.5㎎ / L, THMFP> 70㎍ / L, Chl-a> 30㎎/㎥or less constant process, if you do not need to put pre-ozone showed little impact. It also does not put you in pre-ozone appropriate produce enough power rate savings was calculated as approximately 90 million won. Ability to remove organic materials and the ability to produce disinfection byproducts, and cost-effective decisions by considering the concentration of injection if pre-ozone 1 mg/L was investigated by the appropriate concentration of ozone injection.
The Effects of Muscle Forces on Ankle Joint Kinetics during Postural Balance Control
Choi, Hyeon Ki,Seo, Min Jwa,Koo, Ja Choon,Choi, Hyeon Chang,Cho, Won Hak Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.326 No.-
<P>We assessed the effects of muscle forces on ankle joint kinetics during postural balance control of human boy. Nine male subjects (mean age of 25.8 yrs) participated in the experiment. An ankle joint model assumed ball and socket joint was used, which was capable of three dimensional rotations. A six-camera VICON system was used for motion analysis. Waist pulling system and force platform were adopted for forward sway and GRF (ground reaction force) measurement. We used linear optimization programs to calculate the variation of muscle forces and angular displacements of shank and foot segments. With the experimental data and linear programs, we could calculate joint reaction forces, and bone-on-bone forces. The results presented in this study give us the insights to understand the roles of lower limb muscles during postural balance control and ankle injury mechanism.</P>
Choi, Hyuk,Lee, Heung‐,Man,Nam, Kyoung Won,Choi, Jaesoon,Lee, Jung‐,Joo,Kim, Ho Chul,Song, Seung Joon,Ahn, Chi Bum,Son, Ho Sung,Lim, Choon Hak,Son, Kuk Hui,Park, Yong Doo,Jeong, Gi Seok,Su Blackwell Publishing Inc 2011 Artificial Organs Vol.35 No.6
<P><B>Abstract</B></P><P>In 2002, the paracorporeal pulsatile electro‐mechanical pneumatic ventricular assist device (VAD) began to be developed by the Korea Artificial Organ Center at Korea University under a Health & Medical Technology Research and Development program which finished in 2008. In vitro durability testing was conducted on the paracorporeal pulsatile pneumatic VAD to determine device durability and to evaluate device failures. The 1‐ and 2‐year reliability of the paracorporeal pulsatile pneumatic VAD was shown to be 91.2% and 54.9%, respectively, with an 80% confidence level. Failure modes were analyzed using fault tree analysis, with customized software continuously acquiring data during the test period. After this period, 21 in vivo animal tests were done, with 14 cases of left atrium to left ventricle (LV) inflow cannulation (36Fr)/outflow grafting to descending aorta, and seven cases of apex cannulation of LV to descending aorta (12 mm). The longest postoperative day (182 days) in Korea was recently recorded in in vivo animal testing (bovine, 90 kg, male, 3.5–4.0 L/min flow rate, and 55 bpm).</P>
EXPERIMENTAL SIMULATION OF A DIRECT VESSEL INJECTION LINE BREAK OF THE APR1400 WITH THE ATLAS
Choi, Ki-Yong,Park, Hyun-Sik,Cho, Seok,Kang, Kyoung-Ho,Choi, Nan-Hyun,Kim, Dae-Hun,Park, Choon-Kyung,Kim, Yeon-Sik,Baek, Won-Pil Korean Nuclear Society 2009 Nuclear Engineering and Technology Vol.41 No.5
The first-ever integral effect test for simulating a guillotine break of a DVI (Direct Vessel Injection) line of the APR1400 was carried out with the ATLAS (Advanced Thermal-hydraulic Test Loop for Accident Simulation) from the same prototypic pressure and temperature conditions as those of the APR1400. The major thermal hydraulic behaviors during a DVI line break accident were identified and investigated experimentally. A method for estimating the break flow based on a balance between the change in RCS inventory and the injection flow is proposed to overcome a direct break low measurement deficiency. A post-test calculation was performed with a best-estimate safety analysis code MARS 3.1 to examine its prediction capability and to identify any code deficiencies for the thermal hydraulic phenomena occurring during the DVI line break accidents. On the whole, the prediction of the MARS code shows a good agreement with the measured data. However, the code predicted a higher core level than did the data just before a loop seal clearing occurs, leading to no increase in the peak cladding temperature. The code also produced a more rapid decrease in the downcomer water level than was predicted by the data. These observable disagreements are thought to be caused by uncertainties in predicting countercurrent flow or condensation phenomena in a downcomer region. The present integral effect test data will be used to support the present conservative safety analysis methodology and to develop a new best-estimate safety analysis methodology for DVI line break accidents of the APR1400.
Choi, Byung-Kwan,Cho, Won-Ho,Choi, Chang-Hwa,Song, Geun-Sung,Kim, Choon-Grak,Kim, Hak-Jin The Korean Neurosurgical Society 2010 Journal of Korean neurosurgical society Vol.48 No.5
Objective : Esophageal/hypopharyngeal injury can be a disastrous complication of anterior cervical surgery. The amount of hypopharyngeal wall exposure within the surgical field has not been studied. The objective of this study is to evaluate the chance of hypopharyngeal wall exposure by measuring the amount of axial rotation of the thyroid cartilage (ARTC) and posterior projection of the hypopharynx (PPH). Methods : The study was prospectively designed using intraoperative ultrasonography. We measured the amount of ARTC in 27 cases. The amount of posterior projection of the hypopharynx (PPH) also was measured on pre-operative CT and compared at three different levels; the superior border of the thyroid cartilage (SBTC), cricoarytenoid joint and tip of inferior horn of the thyroid cartilage (TIHTC). The presence of air density was also checked on the same levels. Results : The angle of ARTC ranged from $-6.9^{\circ}$ to $29.7^{\circ}$, with no statistical difference between the upper and lower cervical group. The amount of PPH was increased caudally. Air densities were observed in 26 cases at the SBTC, but none at the TIHTC. Conclusion : Within the confines of the thyroid cartilage, surgeons are required to pay more attention to the status of hypopharynx/esophagus near the inferior horn of the thyroid cartilage. The hypopharynx/esophagus at the TIHTC is more likely to be exposed than at the upper and middle part of the thyroid cartilage, which may increase the risk of injury by pressure. Surgeons should be aware of the fact that the visceral component at C6-T1 surgeries also rotates as much as when the thyroid cartilage is engaged with a retractor. The esophagus at lower cervical levels warrants more careful retraction because it is not protected by the thyroid cartilage.
Effect of Nifedipine on Cardiovascular Responses to Angiotensin Ⅱ in SHR
Choi, Eun Kyung,Hwang, Choon Ha,Lee, Won Jung,Choo, Young Eun 慶北大學校 醫科大學 1988 慶北醫大誌 Vol.29 No.3
칼슘통로차단제인 nifedipine이 angiotensin Ⅱ(Ang Ⅱ)에 대한 승압반응에 미치는 영향을 보기 위하여 urethane으로 마취한 고혈압인 SHR과 정상혈압인 Wistar숫쥐를 사용하였다. 대퇴동맥에 관을 삽입하여 혈압 및 심박수를 physiograph상에서 기록하였고, 대퇴정맥에 삽입한 관으로 AngⅡ(62.5, 125 및 250ng/㎏) 또는 nifedipine을 주사하였다. Nifedipine(5㎍/100g BW)을 주사한 직후, Wistar의 혈압은 10㎜Hg 감소하였다가 5분 후에는 회복되었으나, SHR의 혈압은 32㎜Hg 감소하여 30분이 지나도록 낮은 상태로 유지되었다. Nifedipine주사후 Wistar의 심박수는 변동이 없었으나, SHR에서는 약간 증가하였다가 10분 후에는 회복되었다. 과량의 nifedipine(100㎍)은 Wistar의 혈압을 52㎜Hg 감소하였고 SHR의 혈압은 87㎜Hg 감소하였으며, 맥박수도 현저하게 감소하였다. Ang Ⅱ에 대한 승압반응은 Wistar보다 SHR에서 유의하게 더 컸다. 중등도의 nifedipine은 Ang Ⅱ에 대한 승압반응에는 영향을 미치지 않았으나, 과량의 nifedipine(100㎍)은 Ang Ⅱ에 대한 승압반응을 유의하게 감소시켰다. Ang Ⅱ는 Wistar의 심박수에는 영향을 안 미쳤으나, SHR의 심박수는 약간 감소시켰다. 중등도의 nifedipine은 Ang Ⅱ에 대한 심박수의 반응에는 영향을 미치지 않았다. Ang Ⅱ에 대한 승압반응이나 nifedipine에 대한 혈압강하 반응이 Wistar에서 보다 SHR에서 월등히 심하게 나타나는 것은 SHR의 혈관 근육 세포에서의 칼슘 이동에 변동이 있음을 시사해 주고 있다. Effects of a calcium channel blocker nifedipine on cardiovascular responses to angiotensin Ⅱ(Ang Ⅱ) were studied in urethane anesthetized male Wistar and spontaneously hypertensive rats(SHR). Polyethylene catheters were placed in the femoral vein for drug injections and femoral artery for recording of pressure and heart rate. Nifedipine(5㎍/100g BW) decreased mean arterial pressure(MAP) 10㎜Hg in Wistar rats, but 32㎜Hg in SHR. Hypotensive response to nifedipine was recovered within 5min in Wistar, but that in SHRs was lasted over 30min. Heart rate after nifedipine injection was not changed in Wistar, but was slightly increased about 5min in SHR. Massive dose of nifedipine(100㎍) produced an immediate fall in MAP about 52㎜Hg in Wistar and 87㎜Hg in SHR. Pressor response to Ang Ⅱ was much greater in SHR than in Wistar. The pressor response to Ang Ⅱ was not affected by the moderate dose of nifedipine, but was blunted by the massive dose of nifedipine. Heart rate after Ang Ⅱ injection was not changed in Wistar, but was slightly decreased in SHR. Nifedipine did not affect the responses of heart rate to Ang Ⅱ. Greater pressor response to Ang Ⅱ and greather depressor response to nifedipine in SHR indicate altered handling of calcium in the vascular smooth muscle cells.