운동량변화가 온도변화가 있는 비정상 난류유동장에 미치는 영향

유근종,전원대,김수태 창원대학교 산업기술연구소 2001 産技硏論文集 Vol.15 No.-

In analysis of unsteady turbulent flows with temperature variation, 3 different turbulence models of k-e model, modified k-e model, and Full Reynolds Stress(FRS) model, are applied. 3 Test Cases are selected for verification. These are vertical jet flows with water and sodium, and parallel jet flow with sodium. For overall verification of turbulence models, test cases are analyzed with 2-D and 3-D assumptions. Analysis yields the conclusion that 3-D computation with FRS betters others. However, modified modeling for near wall effect is required to improve its heat transfer characteristic analysis.

Aprotinin의 체외순환에 따른 출혈억제효과

이정은,전대근,김종렬 충남대학교 의과대학 지역사회의학연구소 1992 충남의대잡지 Vol.19 No.2

CPB(cardiopulmonary bypass) is a very complex process ad activated many humoral system which include the coagulation system, firbrinolytic system, kallikrein system, and the complement system, are probably all very important and closely interrelated. It has profound effects the number and especially function of platelets because of contact between blood and gaseous or synthetic solid surface during CPB. These changes increase blood loss after cardiac operations and may transfuse a large amounts of banked blood inevitably which may cause very serious complications including hepatitis and AIDS, etc. Aprotinin is a proteolytic enzyme inhibitor and depress the activation of fibrinolytic system via a powerful antiplasmin activity and may preserve von Willebrand platelet interaction. Two groups of patients were prospectively studied to evaluate the hemostatic effects of high dose aporotinin in open heart operation, first group patients(n=10), at the start of anesthesia 2,000,000 kallikrein inactivator units(KIU) of aprotinin was infused over 20 to 30 minutes. Subsequently, 500,000 KIU/h aprotinin was given untill the end of operation. Additionally, 1,000,000 KIU of aprotinin was in the priming solution of the extracorporeal circuit. Second group patients(n=10) served as controls. The results were as follows, 1. The decrease of hemoglobin and serum protein following CPB was reduced significantly(p<0.05) in aprotinin group. 2. The decrease of platelet number and increase of bleeding time following CPB were reduced in aprotinin group. 3. The intraoperative and postoperative blood loss and the amounts of transfusion of banked blood were reduced significantly(p<0.05) in aprotinin group. In the conclusion, we believe that the use of high dose aprotinin decreases blood loss and reduced the need for banked blood in cardiac patients.

배전계통의 신뢰도에 관한 연구

金慶哲,全大根,姜倫摸 홍익대학교 산업기술연구소 2002 産業技術 Vol.12 No.-

Reliability is the probability of a device or system performing its function adequately for the period of time intended, under the operating conditions. Electric power networks are prime examples of systems where a very high degree of reliability is also absolutely essential for some industrial customers. A system consists of a set of components, interconnected in some purposeful way. The reliability of a system depends on the reliability of its components and on the configuration of the system. The basic indices used to examine and predict the performance of a distribution system at a customer load point are the average outage frequency, average outage duration and average unavailability. The case study system is a kind of radial configuration distribution system. This paper shows that a better meshed distribution configuration was selected by comparing the indices obtained from EDSA's reliability worth assessment of distribution systems program.

세포질내 정자주입법(ICSI)에 있어서 정자흡입 및 난자내 주입방법에 관한 연구

이택후,김항진,송건호,김대근,전상식,박윤규,서태광,전병균,류은경,이은숙,문진수,김광철 경북대학교 의학연구소 2000 경북대학교병원의학연구소논문집 Vol.4 No.1

Study on Method of Sperm Aspiration and Injection into an Oocyte in Intracytoplasmic Sperm Injection(ICSI) Immobilization of spermatozoa prior to intracytoplasmic sperm iniection(ICSI) sometimes results in crooked tail and this makes it difficult to aspirate sperm into an injection pipette tail first. Head-first sperm aspiration into an injection pipette avoid this problem due to the bigger size of the sperm head. The effect of head or tail-first sperm injection into an oocyte on fertilization cleavage, percentage of grade I embryos and development to blastocyst stage in ICSI program has been studied. A single living immobilized spermatozoa from oligoasthenozoospermic patient was injected into an oocyte head-first or tail-first according to the treatment. Eighteen hours after microinjection, oocytes ware inspected for survival and fertilization Fertilized oocytes with two pronuclei were cultured in 30μl drop of mHTF supplemented with 10% heat-inactivated follicular fluid(FF) at 37℃. On day 2. embryo transfer was performed with cleaved embryos. The remaining 2-8 cell stage embryos were co-cultured with BRL cells in mHTF + 10% FF for 72 hours and the developmental stage was observed. The data were analyzed by Analysis of Variance. A total of 164 oocytes from 36 cycles were assigned to earth treatment and ICSI was performed(88 head-first, tail-first). The rates of normal fertilization were 81.8% and 76.3% for head-first and tail-first, respectively. Of the fertilized oocytes, the percentage of cleaved embryos and the percentage of grade 1 embryo among cleaved embryos were 88.9% and 68.8%, 93.1% and 74.1% for head-first and tail-first, respectively. Of the 2-8 cell embryos cultured, 44.4%(16/36) and 50.0%(10/20) for head first and tail first, respectively developed to blastocyst stage. There were no differences in fertilization, cleavage, rates of grade 1 embryos, and development to blastocyst stage. In conclusion, head-first or tail-first sperm injection into an oocyte in ICSI program does not affect fertilization and subsequent embryo development to blastocyst stage in vitro.

Clinical Research Article : Comparison of a supraclavicular block showing upper arm twitching response with a supraclavicular block showing wrist or finger twitching response

( Dae Geun Jeon ),( Won Il Kim ) 대한마취과학회 2010 Korean Journal of Anesthesiology Vol.58 No.5

Background: Although an ultrasound-guided brachial plexus block has become the standard, conventional brachial plexus blocks with a paresthesia or muscle twitch are still performed. However despite eliciting a paresthesia or muscle twitch, there are some cases in whom the brachial plexus block fails. This has been attributed to the difference between the proximal response (PR) and distal response (DR). Therefore, this study compared a supraclavicular block showing a PR with that showing a DR. In addition, clinical data such as success rate, onset time, and complications were examined. Methods: Eighty three patients received a supraclavicular block with a nerve stimulator. All blocks were performed with 1% mepivacaine 40 ml. The subjects were divided into two groups- Group PR (n=20, contraction of triceps or biceps) and Group DR (n=63, flexion or extension of wrist or fingers) according to the types of muscle twitch. The success rate, onset time, and complications were measured and evaluated. Results: The success rate of Group DR (93.7%) was higher than that of Group PR (75.0%) (P<0.05). The onset times of Group PR and DR were 15.3±6.7 min and 14.4±6.0 min, respectively. Conclusions: The elicitation of a DR was more effective in increasing the success rate and reducing the onset time than the elicitation of a PR in a single-injection supraclavicular block. (Korean J Anesthesiol 2010; 58: 464-467)

Clinical Research Article : Cases series: ultrasound-guided supraclavicular block in 105 patients

( Dae Geun Jeon ),( Won Il Kim ) 대한마취과학회 2010 Korean Journal of Anesthesiology Vol.58 No.3

Background: Multiple needle attempts to gain a muscle twitch or a paresthesia for a classical supraclavicular brachial plexus block can increase the risks of nerve damage or pain. The aims of this study were to obtain reliable clinical data on ultrasound-guided supraclavicular blocks, demonstrate the higher success rate and fewer complications, and design an injection method for patients whose brachial plexus can not be located. Methods: 105 patients received an ultrasound-guided supraclavicular block. 40 ml of 1% mepivacaine was injected without a muscle twitch or paresthesia. The groups were divided into two groups-Group A (n=92, patients who had visible brachial plexus) and Group B (n=13, patients whose brachial plexus can`t be located). After the blocks, the clinical characteristics such as the success rate, the time to onset, the extent of the sensory block, and occurrence of complications were evaluated. Results: The Success rate of Group A (98.9%) was higher than that of Group B (84.6%) (P<0.05). The overall success rate was 97.1%. All patients could be operated on under sedation. The time to onset of Group A (12.6±4.4 min) was shorter than that in Group B (23.1±5.1 min) (P<0.05). The overall time to onset was 13.8±5.5 min. There were no serious complications such as pneumothorax. Conclusions: An ultrasound-guided supraclavicular block is very effective in even patients whose brachial plexus can not be located. (Korean J Anesthesiol 2010; 58: 267-271)

Clinical Evaluation of Infraclavicular Block via a Coracoid Approach

( Dae Geun Jeon ),( Jong Il Eun ),( Sang Wook Park ) 대한마취과학회 2006 Korean Journal of Anesthesiology Vol.51 No.6

Background: The infraclavicular approach is believed to overcome the limitations of other brachial plexus blocks. However, there is no reliable clinical data available on Korean patients who undergo this procedure. Therefore, the aim of this study was to obtain reliable data on Korean patients such as the success rate depending on the distal response (DR) or the proximal response (PR), the depth of the needle, time to onset and the sensory distribution, and the clinical efficacy of a coracoid infraclavicular brachial plexus block. Methods: Seventy-one patients received an infraclavicular block with using a nerve stimulator. 40 ml of 1.5% mepivacaine with epinephrine (5 μg/ml), was injected in the presence of an upper extremity motor or sensory response. The clinical characteristics such as the success rate, the depth of the needle inserted, the time to onset, the extent of the sensory block, patient tolerance for a tourniquet and the duration of its use, and the occurrence of complications were all evaluated. Results: The success rate with a DR and PR was 87% and 42%, respectively. The depth of the needle with a DR and PR was 43.5 ± 8.1 mm and 43.2 ± 5.0 mm, respectively. The time to onset with a DR and PR was 23.6 ± 4.3 min and 24.9 ± 4.0 min, respectively. The tourniquet was well tolerated in all patients with successful blocks. There were 5 and 2 cases of vessel puncture with a DR and PR, respectively. There was no case of a pneumothorax. Conclusions: A coracoid infraclavicular brachial plexus block is very effective with few complications when a DR is obtained. The time to onset and the tolerance of a tourniquet were satisfactory. (Korean J Anesthesiol 2006; 51: S 6∼10)

상완골 악성종양의 절제 후 재건술 및 기능적 결과

전대근(Dae-Geun Jeon),이종석(Jong-Seok Lee),박현규(Hyun-Kyoa Park),박재완(Jae-Wan Park),이수용(Soo-Yong Lee) 대한정형외과학회 2000 대한정형외과학회지 Vol.35 No.5

다발성 골연골종 환자에서 이차적으로 발생한 골육종

전대근(Dae-Geun Jeon),박종훈(Jong-Hoon Park),김진욱(Jin-Wook Kim) 대한정형외과학회 2005 대한정형외과학회지 Vol.40 No.3

골연골종은 비교적 흔한 양성 골종양이며 대부분 골소주와 초자연골모로 이루어져있다. 다발성 골연골종에서 이차적으로 악성 종양이 발생하는 것은, 특히 연골육종이 아닌 골육종의 경우는 드문 일이라 할 수 있다. 저자들은 다발성 골연골 종 환자에서 이차적으로 발생한 골육종 환자 1예를 경험하였기에 진단 및 치료 그리고 문헌 고찰과 함께 보고하는 바이다. Osteochondroma, the most frequent benign bone tumor, is composed of trabecular bone covered with a hyaline cartilage cap. It is well known that multiple osteochondromatosis may undergo malignant change. Such sarcomatous change usually present with the form of chondrosarcoma, and transformation to other malignancy is extremely rare. This report describes one case of osteosarcoma arising in patients who had multiple osteochondromatosis, and includes brief review of the literatures.

병기에 따른 연부조직 육종의 분석

전대근(Dae-Geun Jeon),이종석(Jong-Seok Lee),김석준(Sug-jun Kim),강문성(Moon-Seong Kang),곽봉준(Bong-Jun Gwak),조완형(Wan-Hyung Cho),이수용(Soo-Yong Lee) 대한정형외과학회 1999 대한정형외과학회지 Vol.34 No.4