• Nuclear Engineering and Technology
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• 제45권5호
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• pp.625-636
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• 2013

Pressing demands of economic competitiveness, the need for large-scale deployment, minimizing the need of human intervention, and experience from the past events and incidents at operating reactors have guided the evolution and innovations in reactor technologies. Indian innovative reactor 'AHWR' is a pressure-tube type natural circulation based boiling water reactor that is designed to meet such requirements, which essentially reflect the needs of next generation reactors. The reactor employs various passive features to prevent and mitigate accidental conditions, like a slightly negative void reactivity coefficient, passive poison injection to scram the reactor in event of failure of the wired shutdown systems, a large elevated pool of water as a heat sink inside the containment, passive decay heat removal based on natural circulation and passive valves, passive ECC injection, etc. It is designed to meet the fundamental safety requirements of safe shutdown, safe decay heat removal and confinement of activity with no impact in public domain, and hence, no need for emergency planning under all conceivable scenarios. This paper examines the role of the various passive safety systems in prevention and mitigation of severe plant conditions that may arise in event of multiple failures. For the purpose of demonstration of the effectiveness of its passive features, postulated scenarios on the lines of three major severe accidents in the history of nuclear power reactors are considered, namely; the Three Mile Island (TMI), Chernobyl and Fukushima accidents. Severe plant conditions along the lines of these scenarios are postulated to the extent conceivable in the reactor under consideration and analyzed using best estimate system thermal-hydraulics code RELAP5/Mod3.2. It is found that the various passive systems incorporated enable the reactor to tolerate the postulated accident conditions without causing severe plant conditions and core degradation.

• The Korean Journal of Pain
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• 제24권4호
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• pp.205-215
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• 2011

Background: Interventional pain management (IPM) is a branch of medical science that deals with management of painful medical conditions using specially equipped X-ray machines and anatomical landmarks. Interventional physiatry is a branch of physical medicine and rehabilitation that treats painful conditions through intervention in peripheral joints, the spine, and soft tissues. Methods: A cross-sectional study was conducted using three years of hospital records (2006 to 2008) from the Physical Medicine and Rehabilitation Department at Chittagong Medical College Hospital in Bangladesh, with a view toward highlighting current interventional pain practice in a tertiary medical college hospital. Result: The maximum amount of intervention was done in degenerative peripheral joint disorders (600, 46.0%), followed by inflammatory joint diseases (300, 23.0%), soft tissue rheumatism (300, 23.0%), and radicular or referred lower back conditions (100, 8.0%). Of the peripheral joints, the knee was the most common site of intervention. Motor stimulation-guided intralesional injection of methylprednisolone into the piriformis muscle was given in 10 cases of piriformis syndrome refractory to both oral medications and therapeutic exercises. Soft tissue rheumatism of unknown etiology was most common in the form of adhesive capsulitis (90, 64.3%), and is discussed separately. Epidural steroid injection was practiced for various causes of lumbar radiculopathy, with the exception of infective discitis. Conclusion: All procedures were performed using anatomical landmarks, as there were no facilities for the C-arm/diagnostic ultrasound required for accurate and safe intervention. A dedicated IPM setup should be a requirement in all PMR departments, to provide better pain management and to reduce the burden on other specialties.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.103-111
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• 2006

The spray behavior of direct-injection spark-ignition(DISI) engines is crucial for obtaining the required mixture distribution for optimal engine combustion. The spray characteristics of DISI engines are affected by many factors such as piston bowl shape, air flow, ambient temperature, injection pressure and fuel temperature. In this study, the effect of fuel temperature on the spray and combustion characteristics was partially investigated for the wall-guided system. The effect of fuel temperature on the fan spray characteristics was investigated in a steady flow rig embodied in a wind tunnel. The shadowgraphy and direct imaging methods were employed to visualize the spray development at different fuel temperatures. The microscopic characteristics of spray were investigated by the particle size measurements using a phase Doppler anemometry(PDA). The effect of injector temperature on the engine combustion characteristics during cold start and warming-up operating conditions was also investigated. Optical single cylinder DISI engine was used for the test, and the successive flame images captured by high speed camera, engine-out emissions and performance data have been analyzed. This could give the way of forming the stable mixture near the spark plug to achieve the stable combustion of DISI engine.

• The Korean Journal of Pain
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• 제21권2호
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• pp.136-142
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• 2008

Background: A transforaminal epidural steroid injection (TFESI) is one of the methods for the conservative treatment of the lumbar spinal stenosis. As efforts to prolong the therapeutic duration and to predict the outcome of TFESI are very important, we analyzed factors considered to be associated with the therapeutic duration of a TFESI. Methods: Between August 2006 and March 2007, 69 patients (Group A: patients with no pain relief, Group B: patients with pain relief of less than 6 months, Group C: patients with pain relief of more than 6 months) who failed to the medical treatment were included to undertake a fluoroscopic-guided TFESI. Prior to treatment, the VAS (visual analogue scale), ODI (Oswestry disability index), BDI (Beck depression inventory), and BAI (Beck anxiety inventory) scores were determined to evaluate the degree of pain, disability, and psychological status. The VAS and ODI scores were used to assess the degree of pain relief. To identify the total duration of pain relief, regular outpatient visits for six months were conducted, and for the patients who were not able to visit the outpatient clinic regularly, outcome was assessed by telephone interviews after six months. Results: The dural sac cross-sectional area (DSCSA), ODI, pain duration, BDI, BAI, and age showed similar distribution for patients in the A, B, and C groups. Conclusions: The DSCSA, ODI, pain duration, BDI, BAI, and age were not associated with the therapeutic duration of TFESI in lumbar spinal stenosis patients.

• Annals of Rehabilitation Medicine
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• 제42권6호
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• pp.814-821
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• 2018

Objective To suggest rotation angles of fluoroscopy that can bypass the carotid sheath according to vertebral levels for cervical transforaminal epidural steroid injection (TFESI). Methods Patients who underwent cervical spine magnetic resonance imaging (MRI) from January 2009 to October 2017 were analyzed. In axial sections of cervical spine MRI, three angles to the vertical line (${\alpha}$, angle not to insult carotid sheath; ${\beta}$, angle for the conventional TFESI; ${\gamma}$, angle not to penetrate carotid artery) were measured. Results Alpha (${\alpha}$) angles tended to increase for upper cervical levels ($53.3^{\circ}$ in C6-7, $65.2^{\circ}$ in C5-6, $75.3^{\circ}$ in C4-5, $82.3^{\circ}$ in C3-4). Beta (${\beta}$) angles for conventional TFESI showed a constant value of $45^{\circ}$ to $47^{\circ}$ ($47.5^{\circ}$ in C6-7, $47.4^{\circ}$ in C5-6, $45.7^{\circ}$ in C4-5, $45.0^{\circ}$ in C3-4). Gamma (${\gamma}$) angles increased at higher cervical levels as did ${\alpha}$ angles ($25.2^{\circ}$ in C6-7, $33.6^{\circ}$ in C5-6, $43.0^{\circ}$ in C4-5, $56.2^{\circ}$ in C3-4). Conclusion The risk of causing injury by penetrating major vessels in the carotid sheath tends to increase at upper cervical levels. Therefore, prior to cervical TFESI, measuring the angle is necessary to avoid carotid vessels in the axial section of CT or MRI, thus contributing to a safer procedure.

• The Korean Journal of Pain
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• 제32권4호
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• pp.264-270
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• 2019

Background: To develop a rabbit epidural steroid injection (ESI) model for analyzing steroid retention in the tissue, and to assess the difference in steroid retention in the model according to the location and time elapsed after ESI. Methods: Fluoroscopy-guided ESI was performed using the interlaminar approach between the lowest two lumbar segments in 13 female New Zealand white rabbits. Four rabbits were allocated to each of three different groups according to the time of sacrifice: 3, 7, and 15 days post-ESI; the remaining rabbit was sacrificed immediately post-ESI to obtain baseline data. After sacrifice, two segments were harvested: the lowest two lumbar vertebrae and another two lumbar vertebrae immediately above these. The residual steroid amount (RSA) and residual steroid concentration (RSC) in the collected spinal columns were analyzed. A linear mixed model was used to compare RSAs and RSCs between the injected and adjacent segments, and among the number of days until sacrifice; P < 0.05 was considered statistically significant. Results: Both RSA and RSC of the injected segment were significantly higher than those of the adjacent segment (P < 0.001, both). The RSA and RSC significantly decreased over time (P = 0.009 and P = 0.016, respectively). Conclusions: The developed rabbit ESI model verified that significantly more steroid was retained at the injected segment than at the adjacent segment and the residual steroid decreased over time. This model could be useful not only for comparing current steroid medications, but also for developing new, better steroid formulations.

• 대한정형외과학회지
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• 제53권6호
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• pp.513-521
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• 2018

목적: 본 연구는 상지 수술에서 정형외과 의사가 시행한 초음파 유도 액와 상완 신경총 차단술의 유용성 및 합병증을 조사하기 위해 시행하였다. 대상 및 방법: 2017년 3월부터 2017년 5월까지 총 103건에서 초음파 유도 액와 상완 신경총 차단술을 시행하였다. 초음파 및 프로브는 Siemens Acuson X300의 VF13-5 transducer를 사용했다. 수술 부위가 차단한 신경의 해부학적 감각 분포 범위에 포함되는 경우 대상에 포함하였으며, 다발성 손상으로 2시간 이상의 수술 시간이 예상되는 경우와 상완부의 수술은 제외했다. 술기는 lidocaine HCl 2% 20 ml, ropivacaine 0.75% 20 ml, 0.9% normal saline 10 ml로 조성된 50 ml의 혼합액으로, 2명의 정형외과 의사에 의해 동일한 방법으로 시행되었으며, 술기의 성공률(수술 시 마취 유도 상태 여부), 마취 유도 시간(천자침 제거 후 근력과 감각이 모두 소실될 때까지의 시간), 가능한 상지 수술 범위, 수술 후 무통 지속 시간(완전 마취 유도와 수술 후 수술 부위 통증 발생까지의 시간) 및 합병증을 조사하였다. 결과: 술기를 시행한 2명의 의사 간 결과값의 차이는 없었다. 초음파 유도 액와 상완 신경총 차단술에 소요된 needling time은 평균 5.5분(2.5-13.2분), 완전 마취 유도에 걸린 시간은 평균 18.4분(5-40분)이었으며 103명의 환자 중 100명에서 마취가 성공하여 97.1%의 성공률을 보였다. 무통 지속 시간은 평균 402.8분(141-540분)이었다. 마취 후 1예에서 어지러움, 4예에서 구역, 구토 증상을 보였고, 2예에서 입 주변이 얼얼한 증상을 보였으나 7예 모두 당일 완전히 호전되었으며, 총 103예 중 3예에서는 마취 실패로 수술실에서 2예에서 국소 마취제를 추가 투여하였고, 1예에서 전신 마취로 전환하여 수술을 하였다(3예/103예, 2.9%). 결론: 일부 주관절을 포함한 상지 수술에서 정형외과 의사가 시행한 초음파 유도 액와 상완 신경총 차단술은 빠르고 쉽게 마취를 가능하게 하여 수술 대기 시간을 줄일 수 있으며 높은 마취 성공률을 얻을 수 있게 하고 용량 선택적 마취가 가능하게 하는 안전한 술기로 판단된다.

• Journal of Korean Neurosurgical Society
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• 제49권4호
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• pp.245-247
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• 2011

There were only a few reports of mercury on pulmonary artery. However, there is no data on surgery related mercury dissemination. The objective of the present article is to describe one case of postoperative injected mercury dissemination. A 19-year-old man presented severe neck pain including meningeal irritation sign and abdominal pain after injection of mercury for the purpose of suicide. Radiologic study showed injected mercury in the neck involving high cervical epidural space and subcutaneous layer of abdomen. Partial hemilaminectomy and open mercury evacuation of spinal canal was performed. For the removal of abdominal subcutaneous mercury, C-arm guided needle aspiration was done. After surgery, radiologic study showed disseminated mercury in the lung, heart, skull base and low spinal canal. Neck pain and abdominal pain were improved after surgery. During 1 month after surgery, there was no symptom of mercury intoxication except increased mercury concentration of urine, blood and hair. We assumed the bone work during surgery might have caused mercury dissemination. Therefore, we recommend minimal invasive surgical technique for removal of injected mercury. If open exposures are needed, cautious surgical technique to prohibit mercury dissemination is necessary and normal barrier should be protected to prevent the migration of mercury.

• ETRI Journal
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• 제25권5호
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• pp.387-400
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• 2003

Since its launching on 21 December 1999, the Korea Multi-Purpose Satellite-I (KOMPSAT-I) has been successfully operated by the Mission Control Element (MCE), which was developed by the ETRI. Most of the major functions of the MCE have been successfully demonstrated and verified during the three years of the mission life of the satellite. This paper presents the operational performances of the various functions in MAPS. We show the performance and analysis of orbit determinations using ground-based tracking data and GPS navigation solutions. We present four instances of the orbit maneuvers that guided the spacecraft form injection orbit into the nominal on-orbit. We include the ground-based attitude determination using telemetry data and the attitude maneuvers for imaging mission. The event prediction, mission scheduling, and command planning functions in MAPS subsequently generate the spacecraft mission operations and command plan. The fuel accounting and the realtime ground track display also support the spacecraft mission operations.

• 한국가축번식학회지
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• 제24권2호
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• pp.199-208
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• 2000

본 연구에서는 한우의 난소의 변화 주기를 이용한 난포란 채란, 채란시 음압의 정도, 난포란의 채취용 바늘의 직경에 따른 효과, 난포자극호르몬을 이용하여 난소의 난포발달자극의 효과, 생체에서 생산된 미성숙 난포란을 이용하여 체외에서 수정란을 생산한 다음 동결란과 신선란을 이식하여 결과를 도출하였는데, 그 결과는 다음과 같이 요약될 수 있다. 1. 한우의 난소에서 난포기와 황체기로 구분하여 생체로부터 난포란을 채란할 경우 황체기는 4.2$\pm$2.9개를, 난포기에는 4.4$\pm$3.5개를 채란할 수 있었는데 유의적인 차는 인정이 되지 않았다 (P＜0.05). 2. 한우에서 난포란을 채란할 때 적당한 음압의 수준은 40~120mmHg의 범위가 적 당하다는 것을 알 수 있었다. 40, 80, 120mmHg에서의 채란수는 각각 4.2$\pm$3.2, 4.3$\pm$3.4, 4.5$\pm$3.4개였고, 회수율은 각각 49, 47, 45%를 보였는데 유의적인 차는 없었다(P＜0.05). 3. 난포란 채란에 이용되는 채란용 바늘의 직경의 차이에서 난포란의 채란수 (율)에는 17G에서는 4.4$\pm$3.5 (54%)개를, 18G 에서는 3.0$\pm$1.8 (45%)개의 채란수를 얻었는데 유의적인차 (P＜0.05)는 없었고, 채란난자의 채란등급에서도 채란바늘의 직경차이에도 표에 보는 바와 같이 유의적인 차가 없었다 (P＜0.05). 4. 난소에서 보다 많은 난포의 발달을 유도하여 난포란의 채란수 (율)를 증가시키기 위해 난포자극호르몬을 투여한 결과, 근육주사법에서는 증가난포수(율)는 6.2$\pm$2.3 (69.2)개를, 피하주사법에서는 1.1$\pm$2.7 (10.5%)개가 증가하는 효율을 보였는데 주사법에 따른 유의차는 없었고 (P＜0.05), 호르몬주사량에 따른 난포발달수 (율) 은 400mg 을 주사한 그룹에서는 6.3$\pm$2.4 (64.6 %)개를, 200mg 을 주사한 그룹에서는 4.1$\pm$3.2 (50.9%) 개가 증가하는 효율을 보였는데 유의적인 차는 없었다 (P＜0.05). 5. 한우의 체내에서 뽑은 난포란을 이용하여 수정란을 생산한 후 공란우에 대해 이식을 실시한 결과, 동결란을 이식한 경우의 수태율은 11.1% 를, 신선란을 이식한 결과 46.2% 의 수태율을 얻었는데, 동결란보다는 신선란의 수태효율에서 유의적으로 높은 결과를 얻었다(P＜0.05). 본 연구에서는 한우로부터 다수의 난포란을 안정적으로 채란하여 우수한 수정란의 연속적인 생산 및 이식의 가능성을 확인하였다.