• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1289-1294
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• 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.

• Journal of IKEEE
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• v.19 no.2
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• pp.265-270
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• 2015

In this paper, we proposed a dual-directional SCR (silicon-controlled rectifier) based ESD (electrostatic discharge) protection circuit. In comparison with conventional SCR, this ESD protection circuit can provide an effective protection against ESD pulses in the two opposite directions, so the ESD protection circuit can be discharged in two opposite direction. The proposed circuit has a higher holding voltage characteristic than conventional SCR. These characteristic enable to have latch-up immunity under normal operating conditions as well as superior full chip ESD protection. it was analyzed to figure out electrical characteristics in term of individual design parameters. They are investigated by using the Synopsys TCAD simulator. In the simulation results, it has trigger voltage of 6.5V and holding voltage increased with different design parameters. The holding voltage of the proposed circuit changes from 2.1V to 6.3V and the proposed circuit has symmetrical I-V characteristic for positive and negative ESD pulse.

• Journal of Gastric Cancer
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• v.22 no.4
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• pp.339-347
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• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.6
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• pp.496-501
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• 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
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• v.11 no.3
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• pp.155-161
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• 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.

• Journal of the Korean Society of Earth Science Education
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• v.14 no.2
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• pp.146-158
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• 2021

We are to introduce an example of ESD in connection with SDGs through liberal arts courses opened at the College of Education. We analyzed the awareness of the carbon footprint expressed by 42 preservice teachers in a class designed in connection with SDGs 13 goal, 'climate action'. The pre-service teachers wrote a carbon diet diary, a checklist for the level of practice that emits carbon in daily life, and freely expressed the source and proportion of their carbon emissions through the carbon footprint drawing activity. In items of electricity use, public transportation use, and garbage disposal, the level of practice was positive, but water use was analyzed in a negative way. The pre-service teachers who expressed the carbon footprint in 2-3 items reached a majority, showing limitations in recognizing the carbon emission situation in their daily life. Pre-service teachers will be the main actors of education on the environmental issues of the earth at the school site, and the carbon literacy of pre-service teachers will directly or indirectly affect students. We hope that various ESD programs linked to the 17 SDGs will be developed and applied to the educational field to contribute to sustainable global environmental education.