어음행위의 대리(代理)

이정한 연세대학교 사회과학연구소 1972 社會科學論集 Vol.5 No.-

방전플라즈마 소결 공정을 이용한 WC-Co-B₄C 소재의 기계적 특성평가

이정한,박현국,Lee, Jeong-Han,Park, Hyun-Kuk 한국재료학회 2021 한국재료학회지 Vol.31 No.7

In this study, binderless-WC, WC-6 wt%Co, WC-6wt% 1 and 2.5 B₄C materials are fabricated by spark plasma sintering process (SPS process). Each fabricated WC material is almost completely dense, with a relative density up to 99.5 % after the simultaneous application of pressure of 60 MPa. The WC added Co and Co-B₄C materials resulted in crystalline growth. The WC with HCP crystal structure has respective interfacial energy (basal facet direction: 1.07 ~ 1.34 J·m^-2, prismatic direction: 1.43 ~ 3.02 J·m^-2) that depends on the grain growth direction. It is confirmed that the continuous grain growth, biased by the basal facet, which has relatively low energy, is promoted at the WC/Co interface. As abnormal grain growth takes place, the grain size increases more than twice from 0.37 to 0.8 um. It is found through analysis that the hardness property also greatly decreases from about 2661.4 to 1721.4 kg/mm², along with the grain growth.

급성 충수염 환자의 성별과 연령별 분석

이정한,문태일,임치영,추용식,고대이,김성택,배진건,김옥준,최성욱,손석우 대한응급의학회 2004 大韓應急醫學會誌 Vol.15 No.5

P u r p o s e: This retrospective study was performed to investigate epidemiological characteristics in terms of the ageand the sex-specific incidences in patients with perforated or nonperforated appendicitis. M e t h o d: The study population comprised 314 patients who underwent appendectomies for suspected acute appendicitis between March 2002 and August 2003. This study used the student t-test, the coefficient of correlation, and the Cochran-Mantel-Haenszel Chi-square statistics. R e s u l t s: The incidence of nonperforated appendicitis was higher. Perforated appendicitis occurred at almost the same incidence in both sexes. However, the incidence of perforated appendicitis was high in small children and the elderly. The statistics of this study proved that the incidence of perforated appendicitis of the elderly was considerable. C o n c l u s i o n s: We suggest that the elderly need careful examination and rapid evaluation. Also, we suggest that since perforated appendicitis has a long duration of treatment, diagnostic accuracy is needed.

落後地域開發構想을 위한 한 地域模型

李正漢 경남발전연구원 1993 중점정책연구 기본연구 Vol.- No.-

심장질환에서의 PET 역할

이정한 주식회사 녹십자 2002 녹십자의보 Vol.30 No.1

비정질반도체 재료와 응용

이정한 대한전기학회 1975 전기의 세계 Vol.24 No.6

금속과 원소반도체의 접촉으로 이루어진 점접촉트란지스터를 출발점으로 한 P-N접합트란지스터는 4반세기동안 반도체전자 소자의 중심이었다. 이와 같은 반도체소자는 단결정반도체의 특성을 이용한 것으로 그 제작에 있어 거의 완전에 가까운 결정구조와 극도의 화학적순수성이 요구되는 것이다. 이와 같은 요구조건은 접합형 반도체소자제작에 큰 제한을 주게 된다. Gunn Diode, Impatt Diode등으로 반도체소자는 Bulk형식의 것이 각광을 받게 되었으며 MOS형식의 FET에 이르러 신기원을 이루게 되었다. 이리하여 MOS기술은 Sapphire기반을 도입함으로써 SOS기법으로 발전을 거듭하게 되었다. 그러나 정질반도체의 이용이라는 근본적 개념에서는 이탈치못하고 있다. 이상과 같은 정질반도체소자에 대응하여 반대적 입장에서 불순물농도의 영향이 적은 비정질반도체의 연구가 70년이후 미국을 중심으로 활발하게 전개되고 있다. 그 연구 및 개발결과는 2년마다 이루어지는 액체비정질반도체국제회의에서 종합되고 있다. 이 분야에서의 연구는 1968년 Ovshinsky가 비산화물 Chalcogenide glass 비정질박막에서의 빠른 응답속도의 양극대칭성 Switching 현상 발견을 계기로 신국면을 개척하게 된 것이다. 이들 비정질반도체에 대한 물성론적 흥미와 응용면에 관한 기대로부터 전도기구의 해명과 응용회로의 개발연구가 급속히 진전되고 있다.

영혼은 정신을, 뇌는 지성을 담당한다? : 뇌의 실체를 알면 바뀌는 것들

이정한 한국뇌과학연구원 2022 브레인 Vol.95 No.-

Anesthesia for ambulatory surgery

이정한 대한마취통증의학회 2017 Korean Journal of Anesthesiology Vol.70 No.4

Ambulatory anesthesia allows quick recovery from anesthesia, leading to an early discharge and rapid resumption of daily activities, which can be of great benefit to patients, healthcare providers, third-party payers, and hospitals. Recently, with the development of minimally invasive surgical techniques and short-acting anesthetics, the use of ambulatory surgery has grown rapidly. Additionally, as the indications for ambulatory surgery have widened, the surgical methods have become more complex and the number of comorbidities has increased. For successful and safe ambulatory anesthesia, the anesthesiologist must consider various factors relating to the patient. Among them, appropriate selection of patients and surgical and anesthetic methods, as well as postoperative management, should be considered simultaneously. Patient selection is a particularly important factor. Appropriate surgical and anesthetic techniques should be used to minimize postoperative complications, especially postoperative pain, nausea, and vomiting. Patients and their caregivers should be fully informed of specific care guidelines and appropriate responses to emergency situations on discharge from the hospital. During this process, close communication between patients and medical staff, as well as postoperative followup appointments, should be ensured. In summary, safe and convenient methods to ensure the patient’s return to function and recovery are necessary.

Effects of topical dexamethasone in postoperative sore throat

이정한,김수빈,이원진,기승희,김명훈,조광래,임세훈,이근무,최들녘,오민경 대한마취통증의학회 2017 Korean Journal of Anesthesiology Vol.70 No.1

Background: Postoperative sore throat (POST) is a complication that undermines patient satisfaction and increases discomfort in the postoperative period. The present study examined the effects of dexamethasone gargle and endotracheal tube cuff soaking on the incidence and severity of POST. Methods: Ninety patients undergoing laparoscopic cholecystectomy were randomly allocated into three groups: 0.9% normal saline gargling and tube soaking (group C), 0.05% dexamethasone solution gargling and 0.9% normal saline tube soaking (group G), 0.9% normal saline gargling and 0.05% dexamethasone tube soaking (group S). The incidence and severity of POST were then assessed and recorded at 24 hours after surgery. Results: The total incidence of POST was significantly different among the groups (P < 0.05), and group S exhibited a significantly lower incidence of POST than group C (P < 0.0167). In addition, the POST intensity of group G and group S was less severe than those of group C (Both P < 0.0167). Conclusions: Among patients undergoing laparoscopic cholecystectomy, those who gargled with 0.05% dexamethasone solution exhibited lower severity of POST than the control group, and those whose endotracheal tube cuff was soaked in the dexamethasone solution before intubation exhibited significantly lower incidence and severity of POST than the control group.

Comparison of dexmedetomidine and remifentanil for attenuation of hemodynamic responses to laryngoscopy and tracheal intubation

이정한,김효중,김현태,김명훈,조광래,임세훈,이군무,김영재,신치만 대한마취통증의학회 2012 Korean Journal of Anesthesiology Vol.63 No.2

Background: This study was designed to compare the effect of dexmedetomidine and remifentanil used in anesthetic induction on hemodynamic change after direct laryngoscopy and tracheal intubation. Methods: A total of 90 ASA class 1 or 2 patients were randomly assigned to one of 3 groups to receive one of the following treatments in a double-blind manner: normal saline (Group C, n = 30), dexmedetomidine 1 μg/kg (Group D, n = 30), remifentanil 1 μg/kg (Group R, n= 30). Anesthesia was induced with propofol 2 mg/kg and rocuronium 0.6 mg/kg and maintained with 2 vol% sevoflurane and 50% nitrous oxide in oxygen. In group D, dexmedetomidine 1 μg/kg was infused for 10 min before tracheal intubation. Patients in group R was received 1 μg/kg of remifentanil 1 minute before tracheal intubation. The systolic blood pressure, diastolic blood pressure and heart rate were recorded from entrance to operation room to 5 min after tracheal intubation. Results: The percent increase in systolic and diastolic blood pressure due to tracheal intubation in group D and R were significantly lower than that of group C (P < 0.05). The heart rate 1 min after tracheal intubation was lower in groups R and D than in the group C (P < 0.05). Conclusions: In healthy normotensive patients, the use of dexmedetomidine during anesthetic induction suppressed a decrease in blood pressure due to anesthetic induction and blunted the hemodynamic responses to endotracheal intubation. Background: This study was designed to compare the effect of dexmedetomidine and remifentanil used in anesthetic induction on hemodynamic change after direct laryngoscopy and tracheal intubation. Methods: A total of 90 ASA class 1 or 2 patients were randomly assigned to one of 3 groups to receive one of the following treatments in a double-blind manner: normal saline (Group C, n = 30), dexmedetomidine 1 μg/kg (Group D, n = 30), remifentanil 1 μg/kg (Group R, n= 30). Anesthesia was induced with propofol 2 mg/kg and rocuronium 0.6 mg/kg and maintained with 2 vol% sevoflurane and 50% nitrous oxide in oxygen. In group D, dexmedetomidine 1 μg/kg was infused for 10 min before tracheal intubation. Patients in group R was received 1 μg/kg of remifentanil 1 minute before tracheal intubation. The systolic blood pressure, diastolic blood pressure and heart rate were recorded from entrance to operation room to 5 min after tracheal intubation. Results: The percent increase in systolic and diastolic blood pressure due to tracheal intubation in group D and R were significantly lower than that of group C (P < 0.05). The heart rate 1 min after tracheal intubation was lower in groups R and D than in the group C (P < 0.05). Conclusions: In healthy normotensive patients, the use of dexmedetomidine during anesthetic induction suppressed a decrease in blood pressure due to anesthetic induction and blunted the hemodynamic responses to endotracheal intubation.