• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.1289-1294
• /
• 2008

Electrostatic discharge(ESD) phenomenon is a serious reliability concern. It causes approximately most of all field failures of IC. To quality the ESD immunity of IC product, there are some test methods and standards developed. ESD events have been classified into 3 models, which are HBM, MM and CDM. All the test methods are designed to evaluate the ESD immunity of IC products. This study provides an overview among ESD test methods on ICs and an efficient ESD stress method. We have estimated on all pin combination about the positive and negative ESD stress. We make out the weakest stress mode. This mode called a worst-case mode. We proposed that positive supply voltage pin and I/O pin combination is efficient because it is a worst-case mode.

• 전기전자학회논문지
• /
• 제19권2호
• /
• pp.265-270
• /
• 2015

본 논문에서는 높은 홀딩 전압을 갖는 SCR(silicon-controlled rectifier)기반 양 방향성 ESD 보호회로를 제안하였다. 일반적인 ESD 보호회로와 달리 양방향의 ESD Stress mode의 방전경로를 제공하며 높은 홀딩전압으로 latch-up면역 특성을 갖어 효과적인 ESD보호를 제공한다. 또한, 높은 홀딩전압을 위한 설계변수인 Gate Length와 N+bridge Length의 길이 변화에 따른 시뮬레이션을 Synopsys사의 TCAD 시뮬레이터를 사용하여 확인 하였다. 시뮬레이션 결과 2.1V에서 6.5V까지 홀딩 전압의 증가로 latch-up 면역 특성을 개선 하였으며, 기존 SCR보다 6.5V의 낮은 트리거 전압특성을 갖고 있어 제안된 ESD 보호 회로는 5V 이상의 공급전압을 갖는 application에 적용 가능하다.

• Journal of Gastric Cancer
• /
• 제22권4호
• /
• pp.339-347
• /
• 2022

Purpose: Lymphovascular invasion is a criterion for non-curative resection in patients who have undergone endoscopic submucosal dissection (ESD) for early gastric cancer (EGC). We aimed to determine the rate of extragastric metastasis (EGM) and identify the predictors of EGM in patients with negative resection margins (R0 resection) and lymphovascular invasion in post-ESD pathology. Materials and Methods: A total of 2,983 patients underwent ESD for EGC. Among them, 110 had a pathology of R0 resection and positive lymphovascular invasion. Patients underwent additional gastrectomy (n=63) or further follow-up without gastrectomy (n=47). Results: The 110 patients were assigned to one of the 3 groups according to ESD indications based on post-ESD pathology. The first group satisfied the absolute indication for ESD (n=18), the second group satisfied the expanded indications for ESD (n=34), and the last group satisfied the beyond indication (n=58). The number of occurrences of EGM in each group was 1 (5.6%), 3 (8.8%), and 3 (5.2%), respectively. The logistic regression analysis adjusted for age, sex, tumor size, and indication for ESD, showed that larger tumor size was associated with EGM (odds ratio, 1.76; 95% confidence interval, 1.00-3.10; P=0.048). In contrast, ESD indication criteria did not affect EGM (P=0.349). Conclusions: Tumor size was the only predictive indicator for EGM in patients who underwent R0 resection and lymphovascular invasion on post-ESD pathology. Even patients with pathology corresponding to the absolute indication criteria of ESD had lymphovascular invasion, which means that they require additional gastrectomy due to the risk of EGM.

• 한국전기전자재료학회논문지
• /
• 제20권6호
• /
• pp.496-501
• /
• 2007

In order to enhance sintering characteristics on the $ZnO-Pr_6O_{11}$ based multilayer chip varistors (MLVs), a response surface analysis using central composite design method were carried out. As a result, varistor voltage($V_{1mA}$), nonlinear coefficient ($\alpha$), leakage current ($I_L$) and capacitance (C) were considered to be mainly affected by sintered temperature and holding time. MLVs sintered at $1200^{\circ}C$ and above $1200^{\circ}C$ revealed poor electrical characteristics, possibly due to the reaction between electrode materials(Pd) and $ZnO-Pr_6O_{11}$ based ceramics. On the sintering temperature range $1150{\sim}1175^{\circ}C$, nonlinear coefficient ($\alpha$) and leakage current ($I_L$) were shown to be $60{\sim}69$ and below $0.3{\mu}A$, respectively. In particular, MLVs sintered at $1175^{\circ}C$, 1.5 hr and $2^{\circ}C/hr$ (cooling speed) showed stable ESD(Electrical Static Discharge) characteristics under the condition of 10 times at 8 Kv with deviation varistor voltage, and deviation nonlinear coefficient were 0.3% and 0.33% (at positive), 0.55% (at negative), respectively.

• Journal of Gastric Cancer
• /
• 제11권3호
• /
• pp.155-161
• /
• 2011

Purpose: To determine the diagnostic utility of a frozen section biopsy in patients undergoing endoscopic submucosal dissection (ESD) for early gastric neoplasms with obscure margins even with chromoendoscopy using acetic acid and indigo carmine (AI chromoendoscopy). Materials and Methods: The lateral spread of early gastric neoplasms was unclear even following AI chromoendoscopy in 38 patients who underwent ESD between June 2007 and May 2011. Frozen section biopsies were obtained by agreement of the degree of lateral spread between two endoscopists. Thus, frozen section biopsies were obtained from 23 patients (FBx group) and not in the other 15 patients (AI group). Results: No significant differences were observed for size, histology, invasive depth, and location of lesions between the AI and FBx groups. No false positive or false negative results were observed in the frozen section diagnoses. Adenocarcinoma was revealed in three patients and tubular adenoma in one, thereby changing the delineation of lesion extent and achieving free lateral margins. The rates of free lateral resection margins and curative resection were significantly higher in the FBx group than those in the AI group. Conclusions: Frozen section biopsy can help endoscopists perform more safe and accurate ESD in patients with early gastric neoplasm.

• 대한지구과학교육학회지
• /
• 제14권2호
• /
• pp.146-158
• /
• 2021

사범대학에 개설된 교양 강의를 통해 지속가능발전목표(SDGs)와 연계하여 지속가능발전교육(ESD)을 실시한 사례를 소개하고자 한다. SDGs 13번 목표인 '기후변화 대응'과 연계하여 설계된 수업에서 42명의 예비교사들이 표출한 탄소 발자국(carbon footprint)에 대한 인식을 분석하였다. 예비교사들은 일상생활에서 탄소를 배출하는 실천 정도에 대한 체크리스트인 탄소 다이어트 다이어리를 작성하고, 탄소 발자국 그리기 활동을 통해 자신이 배출하는 탄소의 출처와 비율을 자유롭게 표현하였다. 전기 사용, 대중교통 이용, 쓰레기 처리 항목에서는 긍정적인 실천 정도를 나타내었으나, 수도 사용에 대해서는 부정적인 방향으로 분석되었다. 탄소 발자국을 2-3가지 항목으로 표현한 예비교사들이 과반수에 달하여 자신의 일상생활에서 탄소 배출 상황을 인식하는데 한계를 나타내었다. 예비교사들은 학교현장에서 지구의 환경문제를 교육하는 주체가 될 것이며, 예비교사들의 탄소 소양(carbon literacy)은 학생들에게 직간접적 영향을 미치게 될 것이다. 17가지 SDGs와 연계되는 다양한 지속가능발전교육 프로그램이 개발되고 교육현장에 적용되어 지속가능한 지구환경교육에 기여하기를 바란다.