• Journal of Adhesion and Interface
• /
• v.24 no.2
• /
• pp.64-68
• /
• 2023

Organic field-effect transistors (OFETs) are attracting attention in the field of next-generation electronic devices, and they can be fabricated on a flexible substrate using an organic semiconductor as a channel layer. In particular, DPP-based semiconducting conjugated polymers are actively used because they have higher charge carrier mobility than other organic semiconductors, but they are still lower than inorganic semiconductors, so various studies are being conducted to improve the charge carrier mobility. In this study, the charge carrier mobility is improved by controlling the surface energy of the substrate by forming self-assembled monolayers (SAMs). As the surface energy of the substrate is controlled by the SAMs, the crystallinity increases, thereby improving the charge carrier mobility by 14 times from 3.57×10^-3 cm²V^-1s^-1 to 5.12×10^-2 cm²V^-1s^-1

• Journal of the Korean Geotechnical Society
• /
• v.22 no.4
• /
• pp.41-49
• /
• 2006

This paper demonstrates the feasibility of using shallow S-wave, high-resolution seismic reflection surveys to characterize geological structure and stratigraphy of basement rocks for civil engineering purposes. S-wave seismic reflections from depths less than 20 m were recorded along the top of steep readout slopes. Seismic reflection data were recorded using a standard CDP acquisition method with a 24-channel seismograph and a sledge-hammer SH-wave source. The data were acquired using a split-spread source-receiver geometry with a 2 m shot-and-receiver interval, and then were processed to enhance S/N ratio of the data, to improve resolvable power of the seismic section, and to get velocity information of the basement rock. The final seismic reflection profiles using the CDP technique has imaged surfaces as shallow as less than 1m and resolved beds as thin as 1m. The migrated reflection sections possess sufficient quality to correlate the prominent reflection events to the bedding planes and faults identified on the readout outcrops. Similar S-wave reflection surveys could also be used to produce the necessary details of a geological structure of shallow bedrocks to pinpoint optimum locations for monitor wells of civil engineering purposes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.4
• /
• pp.413-417
• /
• 2023

Gallium Oxide (Ga₂O₃) is preferred as a material for next generation power semiconductors. The Ga₂O₃ should solve the disadvantages of low thermal resistance characteristics and difficulty in forming an inversion layer through p-type ion implantation. However, Ga₂O₃ is difficult to inject p-type ions, so it is being studied in a heterojunction structure using p-type oxides, such as NiO, SnO, and Cu₂O. Research the lateral-type FET structure of NiO/Ga₂O₃ heterojunction under the Gate contact using the Sentaurus TCAD simulation. At this time, the VG-ID and VD-ID curves were identified by the thickness of the Epi-region (channel) and the doping concentration of NiO of 1×10¹⁷ to 1×10¹⁹ cm-3. The increase in Epi region thickness has a lower threshold voltage from -4.4 V to -9.3 V at I_D = 1×10^-8 mA/mm, as current does not flow only when the depletion of the PN junction extends to the Epi/Sub interface. As an increase of NiO doping concentration, increases the depletion area in Ga₂O₃ region and a high electric field distribution on PN junction, and thus the breakdown voltage increases from 512 V to 636 V at I_D =1×10^-3 A/mm.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.5A
• /
• pp.729-735
• /
• 2008

For well-constructed concrete, its service life is a long period and it has an enough durability performance. For cracked concrete, however, it is clear that cracks should be a preferential channel for the penetration of aggressive substance such as chloride ions accoding to author's previous researches. Even though crack width can be reduced due to the high reinforcement ratio, the question is to which extend these cracks may jeopardize the durability of cracked concrete. If the size of crack is small, surface treatment system can be considered as one of the best options to extend the service life of concrete structures exposed to marine environment simply in terms of cost effectiveness versus durability performance. Thus, it should be decided to undertake an experimental study to deal with the effect of different types of surface treatment system, which are expected to seal the concrete and the cracks to chloride-induced corrosion in particular. In this study, it is examined the effect of surfaced treated systems such as penetrant, coating, and their combination on chloride penetration through microcracks. Experimental results showed that penetrant can't cure cracks. However, coating and combined treatment can prohibit chloride penetration through cracks upto 0.06 mm, 0.08 mm, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2021.10a
• /
• pp.189-192
• /
• 2021

YouTube, the world's largest video sharing platform, is loved by many users in that it provides numerous videos and makes it easy to get helpful information. However, the ratio of like/hate for each video varies according to the subject or upload time, even though they are in the same channel; thus, previous studies try to understand the reason by inspecting some numerical statistics such as the ratio and view count. They can help know how each video is preferred, but there is an explicit limitation to identifying the cause of such preference. Therefore, this study aims to determine the reason that affects the preference through matching between topic words extracted from comments in each video and non-sympathetic types defined in advance. Among the top 10 channels in the field of 'pets' and 'cooking', where outliers occur a lot, the top 10 videos (the threshold of pet: 4.000, the threshold of cooking: 0.723) with the highest ratio were selected. 11,110 comments collected totally, and topics were extracted and matched with non-sympathetic types. The experimental results confirmed that it is possible to predict whether the rate of like/hate would be high or which non-sympathetic type would be by analyzing the comments.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.3B
• /
• pp.301-310
• /
• 2006

Typically, we needs enormous national budget for the flood control project and so the project usually has big influence on the national economy. Therefore, the reliable estimation of flood damage is the key issue for the economic analysis of the flood control project. This study aims to provide a GIS based technique for distributed flood damage estimation. We consider two aspects of engineering and economic sides, which are the inundation analysis and MD-FDA (Multi-Dimensional Flood Damage Analysis), for the flood damage assessment. We propose the analysis framework and data processing using GIS for assessing flood damages. The proposed methodology is applied to the flood control channel project for flood disaster prevention in Mokgamcheon/Dorimcheon streams and this study presents the detailed GIS database and the assessment results of flood damages. This study may have the worth in improving practical usability of MD-FDA and also providing research direction for combining economic side with the engineering aspect. Also this distributed technique will help decision-making in evaluating the feasibility of flood damage reduction programs for structural and nonstructural measures.

• (The) Research of the performance art and culture
• /
• no.22
• /
• pp.157-183
• /
• 2011

This study is to find out the legitimacy and features of Honam Choreography via Lee Mae-bang and Han Jin-ok, two of the masters, and to seek better and more creative ways to pass it down in view of regional particularities. The study looks into the traditional choreography's multi-conceptuality that is derived from various forms of art and lends it its identity with the original notion rooted in Buddhist dancing. Despite the local cultural traits of the Honam area, the fact that Lee Mae-bang is more feminine and Han Jin-ok more masculine shows the two's worlds of dancing have been created from different perspectives, though they are quite common in their roots and locales. The particularities of passing down traditional choreography are given a thought in this study with the distinction and identity taken into account. Also, it will give an opportunity to discuss the importance of localism as aesthetic consciousness and communica tion channel. In any case, there is no doubt that local difference and communica tion make a very important source of culture when we look into the originality of the choreography.

• Journal of Digestive Cancer Research
• /
• v.1 no.2
• /
• pp.104-107
• /
• 2013

Gallbladder (GB) cancer is highly malignant neoplasm found in advanced stage and chemotherapy commonly plays a palliative role in GB cancer. We report a case of unresectable GB cancer treated with chemotherapy followed by extended cholecystectomy. Fifty-six-year-old male visited our hospital with weight loss and dyspnea on exertion. Computed tomography detected pulmonary embolism and diffuse GB wall thickening with para-aortic lymph node enlargement. The length of common channel was 23mm at magnetic resonance cholangiopancreatography which stands for anomalous union of the pancreaticobiliary duct. Anticoagulation was started for pulmonary embolism. GB wall mass was regarded as unresectable GB cancer with distant lymph node metastasis. Gemcitabine and cisplatin combination chemotherapy was carried out for 6 cycles. Primary tumor was stationary but multiple enlarged lymphnodes were almost completely disappeared. Extended cholecystectomy with hepaticojejunostomy was performed. Post-operative tumor stage was T3N1 (stage IIIB) and R0 resection was achieved. After operation he has no evidence of disease recurrence for 6 months.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.25 no.6
• /
• pp.479-493
• /
• 2023

The need for safety management has arisen due to the increasing number of years of operated underground structures, such as tunnels and utility tunnels, and accidents caused by those aging infrastructures. However, in the case of privately managed underground utility ducts, there is a lack of detailed guidelines for facility safety and maintenance, resulting in inadequate safety management. Furthermore, the absence of basic design information and the limited space for safety assessments make applying currently used non-destructive testing methods challenging. Therefore, this study suggests non-destructive inspection methods using ultrasonic and impact-echo techniques to assess the quality of underground structures. Thickness, presence of rebars, depth of rebars, and the presence and depth of internal defects are assessed to provide fundamental data for the safety assessment of box-type general underground structures. To validate the proposed methodology, different conditions of concrete specimens are designed and cured to simulate actual field conditions. Applying ultrasonic and impact signals and collecting data through multi-channel accelerometers determine the thickness of the simulated specimens, the depth of embedded rebar, and the extent of defects. The predicted results are well agreed upon compared with actual measurements. The proposed methodology is expected to contribute to developing safety diagnostic methods applicable to general underground structures in practical field conditions.

• Journal of Korean Society of Disaster and Security
• /
• v.16 no.4
• /
• pp.147-156
• /
• 2023

Because the behavior of cable bridges is dominated by dynamic response and is relatively complex, short- and long-term field monitoring are often required to evaluate the bridge condition. If a permanent SHMS (Structural Health Monitoring System) is not installed, a portable monitoring system is needed for the checking of bridge condition. In this case, it can be difficult to operate the portable monitoring system due to limited conditions such as power and communication according to the location and type of the bridge. In this study, the portable-based smart structural response monitoring system is developed that can be effectively used for short- and long-term monitoring of cable bridges in Korea and Southeast Asia. The developed system is a multi-channel portable data acquisition and analyzer that can be operated for a long time in the field using its own power supply system, and is included with the automated analysis algorithm for the dynamic characteristics of cable bridges using real-time data. In order to evaluate the field applicability of the developed system, field demonstration was conducted on cable bridges in Korea and Vietnam. Through the demonstration, the reliability and efficiency of field operation of the developed system were confirmed, and additionally, the possibility of application to overseas markets was confirmed in cable bridge monitoring field.