• Journal of the Korean Vacuum Society
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• v.13 no.3
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• pp.120-126
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• 2004

A damage-reduced trench was investigated in view of the defect distribution along trench sidewall and bottom using high resolution transmission electron microscopy, which was formed by HBr plasma and additive gases in magnetically enhanced reactive ion etching system. Adding $O_2$ and other additive gases into HBr plasma makes it possible to eliminate sidewall undercut and lower surface roughness by forming the passivation layer of lateral etching. To reduce the RIE induced damage and obtain the fine shape trench corner rounding, we investigated the hydrogen annealing effect after trench formation. Silicon atomic migration on trench surfaces using high temperature hydrogen annealing was observed with atomic scale view. Migrated atoms on crystal surfaces formed specific crystal planes such as (111), (113) low index planes, instead of fully rounded comers to reduce the overall surface energy. We could observe the buildup of migrated atoms against the oxide mask, which originated from the surface migration of silicon atoms. Using this hydrogen annealing, more uniform thermal oxide could be grown on trench surfaces, suitable for the improvement of oxide breakdown.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1442-1444
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• 2003

폴리머 애자용 shed 재료의 전기방전에 대한 열화내성과 표면이 오염된 조건하에서도 우수한 발수성 유지는 제품의 장기성능에 있어서 가장 중요한 인자들이다. 내트래킹성 확보를 위한 보강재로는 ATH가 주로 사용되고 있으며 ATH의 첨가량이 많을 수록 내트래킹성은 대체로 향상되는 것으로 되어 있다. 그러나 애자 제조시 무결점 성형성의 만족이 대단히 중요하기 때문에 ATH를 고충진하는 경우 사용하는 process oil들의 종류 및 첨가량을 고려한 ATH 첨가량의 최적화는 필요하다. 본 논문에서는 ATH를 170 part로 다량으로 첨가하면서 화학적 구조와 점도가 다른 몇 가지 실리콘 fliud들을 사용하여 무결점 성형에 적합한 가소도를 갖는 컴파운드를 제조하여 기본물성과 초고압 옥외절연물의 shed 재료로서 장기성능에 영향을 주는 방전열화내성과 표면발수성의 회복특성을 평가하였다. 컴파운드의 성형작업성과 관련이 큰 가소도는 fluid 점도에 따라 상당한 차이를 보이므로 실리콘 fluid 종류의 선택과 첨가량의 최적화에는 성형작업성, 발수성 회복특성, 열화내성 등의 고려가 필요하다. 무결점 애자성형을 위한 진공 사출에서 고무 컴파운드의 가소도가 중요한데 동일한 ATH첨가조건에서 일정한 가소도를 갖게 하는데 필요한 양은 fluid들의 종류에 따라서 상당한 차이가 있었다. 코로나 처리후 발수성 회복특성은 fluid들의 분자크기와 반응기의 종류에 따라 상당히 영향을 받았으며 분자가 클수록 초기회복속도는 다소 느렸지만 평상시에 늘 유지되는 상시발수성은 다소 높게 유지되었다. 아크와 트래킹 방전에 의한 무게 감소는 ATH가 과량으로 첨가되어 상당히 적었으며 fluid의 분자가 크면서 페닐기를 가진 fluid들이 첨가된 고무가 우수한 특성을 보였다.

• Journal of KIISE:Information Networking
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• v.30 no.3
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• pp.343-354
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• 2003

This paper describes algorithm that minimizes recovery time of packet loss resulting from handoff in multicast environments and guarantees reliability through interaction of FN(Foreign Network) with PMTP(Predictable Multicast Tree Protocol). To solve the problems that inefficient routing and handoff delay taking plate when using hi-directional tunneling and remote subscription independently in multicast environments, proposed algorithm uses tunneling and rejoining multicast group according to the status of an arriving FA in a foreign network. Furthermore, proposed algorithm sends packet loss information and register message to previous FA or current FA at the same time. so, MH is able to recovery packet loss in handoff delay as soon as possible. As a result of performance analysis, proposed algorithm is more efficient than previous researches and is applicable to existing handoff method without requiring additional procedures.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.19-27
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• 2009

This study was carried out to obtain the basic model to estimate damage degree from the correlation analysis between forest fire and site environment factors and to clarify the restoration trends thorough multi-temporal survey by observing species diversity followed by various treatments at damaged forest area over time. From the derived model, the damage degree of forest fire was higher in the area of dense coniferous stands composed of simple story at the elevation of about 100m and 200m, and on steeper slope area over 30 degree. As results of this study, fire damaged trees are needed to cut down and a mixed stand with deciduous and coniferous species from the same area is desirable for the future species composition on fire damaged forest. Thus, site characteristics, local species, and mixed stands are the main consideration to enhance the vegetation recovery.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.201-210
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• 2021

This study was carried out to investigate the Fagopyrum esculentum (F. esculentum) extracts and vitexin are as the results of microarray, cell proliferation, cell wound recovery, cell cycle, microphage pattern and protein analysis for damage improvement caused by UVB-induced damage. Microarray results showed that UVB-induced increase in DRAM1, Atg2a and Atg13 genes was reduced in F. esculentum ethanol extract and vitexin. Cell proliferation, wound repair, cell cycle, and microphage patterns were improved in F. esculentum ethanol extract and vitexin, while buckwheat ethanol extract and vitexin decreased in both DRAM1, Beclin-1, and LC3 I/II in the vitexin treatment group and p-mTOR and survivin were all increased in protein analysis. It is thought that it can recover to normal and control autophagy, one of the causes of cell aging caused by UVB, to inhibit and regenerate cell death. F. esculentum ethanol extract and vitexin can be used as a functional cosmetic ingredient.

• Journal of Korea Society of Industrial Information Systems
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• v.26 no.1
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• pp.55-65
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• 2021

In this paper, a methodology for reinforcing reverse logistics (RL) activities in a closed-loop supply chain (CLSC) model is proposed. For the methodology, the activities of the recovery center (RC) which can be considered as one of the facilities in the RL are reinforced. By the reinforced activities in the RC, the recovered parts and products after checking and recovering processes of the returned product from customer can be reused in the forward logistics (FL) of the CLSC model. A mathematical formulation is suggested for representing the CLSC model with reinforced RL activities, and implemented using a hybrid genetic algorithm (HGA) approach. In numerical experiment, two different scales of the CLSC model are presented and the performance of the HGA approach is compared with those of some conventional approaches. The experimental results show that the former outperforms the latter in most of performance measures. The robustness of the CLSC model is also proved by regulating various rates of the recovered parts and products in the RC.

• Journal of the Korean GEO-environmental Society
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• v.14 no.8
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• pp.53-60
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• 2013

The compaction control method of national road substructure is using field density test to determine the relative compaction and plate bearing test to check the load bearing capacity. However, these two tests digitize a construction site manager's judgment based on his experience, so mechanical basis is weak. Resilient modulus method, which is recently being used to resolve such problem, is evaluated as a rational design method of pavement structure that can rationally reflect the stress-strain state of pavement materials that is caused by the condition of load repetition of vehicle load. However, the method of measuring the resilient modulus is difficult and lengthy, and it has many problems. To replace it, light falling weight test is recently being proposed as a simple test method. Therefore, this research uses dynamic plate loading test, which quickly and simply measures the elastic modulus of the subgrade and sub-base construction and site of maintenance, to judge the possibility of compaction control of the stratum under the road, and it proposes relation formula by analyzing the result of static load test.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.155-160
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• 1993

The identification of viable myocardium in patients with coronary artery disease and left ventricular dysfunction is an issue of increasing clinical relavance in the current era of myocardial revascularization. There are at least two forms of reversible myocardial dysfunction. Early reperfusion does not always lead to immediate functional improvement; rather, the return of contractility in tissue salvaged by reperfusion is delayed for hours, days or even weeks, a phenomenon that has been termed "stunned myocardium". Some patients with coronary artery disease show myocardial dysfunction at rest which are associated with reduced perfusion, and which disappear after revascularization; this phenomenon has been termed "hibernating myocardium". Recently, cardiac imaging techniques that evaluate myocardial viability on the basis of perfusion-contraction mismatch and inotropic reserve have gained substantial popularity and clinical success. This review focus on the application of $^{201}TI$ and $^{99m}Tc-MIBI$ to address myocardial viability in patients with hibernating and stunned myocardium. It is clear that 4-hour redistribution images of $^{201}TI$ underestimate ischemia and overestimate scar. Delayed imaging and reinjection imaging have been developed for the assessment of viability. Among many protocols suggested, stress-redistribution-reinjection imaging gained most popularity. Although $^{99m}Tc-MIBI$ could identify myocardial viability, $^{201}TI$ reinjection technique was regarded as superior to it. In conclusion, $^{201}TI$ stress, 4-hr rest redistribution, and reinjection imaging technique may be the most preferable method for evaluation of myocardial viability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.1-6
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• 2017

Stents are widely used as the most common method of treating coronary artery disease with implants in the form of a metal mesh. The blood flow is normalized by inserting a stent into the narrowed or clogged areas of the human body. In this study, the mechanical characteristics of a stent are investigated according to the variations of its design parameters by the Taguchi method and finite element analysis. A stent model of the Palmaz-Schatz type was used for the analysis. In the analysis, an elasto-plastic material model was adopted for the stent and a hyper-elastic model was used for the balloon. The main interest of this study is to investigate the effects of the design parameters which reduce the possibility of restenosis by adjusting the recoil amount. A Taguchi orthogonal array was constructed on the model of the stent. The thickness and length and angle of the slot were selected as the design parameters. The amounts of radial recoil and longitudinal recoil were calculated by finite element analysis. The statistical analysis using the Taguchi method showed that optimizing the shape of the stent could reduce the possibility of restenosis. The optimized shape showed improvements of recoil in the radial and longitudinal directions of ~1% and ~0.1%, respectively, compared to the default model.

• The Korean Journal of Malacology
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• v.19 no.1
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• pp.71-79
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• 2003

After the juvenile octopus individuals being discharged, it is hard to separately capture them because they attach strongly to the wall of the aquarium by the suckers on the arms. Therefore, anaesthetics (MS-222 or lidocaine-HCl) are usually used for capture from attachment. The anaesthetized time of the octopus by lidocaine-HCl was more faster 1.6 to 4.5 times under 200 ppm and 6.0 to 6.5 times in 300 to 500 ppm than those in MS-222. In the anaesthetized and recovery rates (%) by the exposed time, the juvenile octopuses were anesthetized by lower concentrations of lidocaine-HCl within the short time, and rapidly recovered from anesthesia. In the secondary anesthesia of the juvenile octopuses exposed with lidocaine-HCl by the elapsed time after the primary anesthesia, the anesthetized time was later in case of lower concentrations and long elapsed times, However, the anesthetized time was faster when their concentrations were higher and the elapsed time after anesthesia were shorter. Recovery from the secondary anesthesia was faster when the elapsed time was long in lower concentration, and was later when the elapsed time was shorter. In case of Octopus ocellatus, anaesthetic effects by lidocaine-HCl concentrations were better than those of MS-222. Doses of lidocaine-HCl and critical time for works at the indoor laboratory were proper in concentration of 100 ppm within 15 min.