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Fabrication of Electrospun Composite Membranes with Silk Powder (실크 입자가 도입된 전기방사 복합막 제조)

  • Seo, Young Jin;Kang, Hoseong;Im, Kwang Seop;Choi, Kang-min;Park, Chi Hoon;Nam, Sang Yong;Jang, Hae Nam
    • Membrane Journal
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    • v.32 no.2
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    • pp.133-139
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    • 2022
  • As the issue of reducing greenhouse gases is emerging due to global warming and extreme weather, research on materials capable of radiative cooling without energy consumption is being actively conducted. Among them, silk is known as a natural self-cooling material, but in the conventional mixing process using chemically powdered silk, there is a problem that the radiative cooling effect disappears by the collapses of the intrinsic crystal structure of silk fibroin, so it is difficult to manufacture it in the form of a film or coating agent for radiative cooling. In this study, various types of membranes were manufactured using silk powder that went through a physical pulverization process that does not damage the intrinsic structure of silk fibroin, and the study was conducted to examine its applicability as a coating agent. Electrospun membranes and flat sheet membranes were prepared by using silk fibroin powder for this purpose, and it was observed that the viscosity of the solution had a significant effect on the membrane fabrication and its properties.

An Analysis of Threat Factors for Strengthen Maritime Safety around Delphi/AHP-Based Launch Site and Flight Paths (Delphi/AHP 기반 발사장 주변 및 비행경로의 해상안전 강화를 위한 위협요인 분석)

  • Ahn-Tae Shin;Byung-Mun Park;Hun-Soo Byun
    • Korean Chemical Engineering Research
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    • v.61 no.2
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    • pp.208-216
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    • 2023
  • In this study, using the Delphi method, 20 responses to 4 questions (need for launch safety control, top-priority considerations for ensuring public safety during launch, necessary improvements for securing maritime safety, and maritime safety threat factors) regarding launch vehicles and public safety were obtained from experts, and their importance was evaluated to analyze the factors that threaten the reinforcement of maritime safety around launch sites and flight paths when launching. According to the results of an analytic hierarchy process (AHP) analysis, the consistency ratio of the four questions was 4.8%, which is lower than CR ≤ 0.1(10%), and the consistency percentage of the lower measurement indicators was 3.9~5.7%. The derived importance and priority of maritime safety threat factors during launching were in the following order: Substantial human and physical damage in case of launch accidents(0.36), Prepare legal bases (e.g., penalty details) regarding maritime control(0.32), Secure the safety of personnel, equipment, and facilities in danger zone(0.31), Unauthorized entry of vessels in maritime control zones and non-compliance to restrictions(0.30). This article can serve as a reference for strengthening maritime safety in areas around launch sites and flight paths.

Experimental Study for Removing Lacquer Layer on Iron Surface by Nd:YAG Laser System (Nd:YAG 레이저를 이용한 철제 표면 옻칠 제거 실험 연구)

  • Park, Chang Su;Cho, Nam Chul;Hwang, Hyun Sung
    • Journal of Conservation Science
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    • v.32 no.3
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    • pp.377-384
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    • 2016
  • There are physical and chemical method for removement of a lacquered layer existing on the surface when gilding an iron Buddha, these caused environmental pollution by surface degradation and is very noxious for conservation scientist's health. Thus, on this study, we conducted a lacquered layer removement experiments using Nd:YAG Laser which is contactless and eco-friendly. Specimens were made by polishing $5{\times}5$ size of iron(99.9%) specimens surfaces evenly and by differing of number of coating of unrefined lacquer, so there were thickness differences of $10{\mu}m$, $20{\mu}m$, and $30{\mu}m$. The laser machine used in this study was Nd:YAG Laser, and we used two wavelength modes; 1064 nm(160~180 mJ) for infrared light region and 532 nm(50~350 mJ) for ultraviolet light region. The experiment done by investigating the transition of specimens' surfaces with laser wavelength, energy, and numbers of investigation. The remain amount of lacquered layer surfaces before/after laser irradiation was investigated by stereoscopic microscope, observation by SEM, Non-contact Surface Roughness Measurement Device, and FT-IR etc. As a result of each analysis, we could verify the thickness of $10{\mu}m$, $20{\mu}m$ of lacquered layer removed without surface degradation when using 1064 nm wavelength with $1.0J/cm^2$ density. We could find out that Nd:YAG Laser is effective for removing remained lacquered layers when gilding an iron Buddha. In the future, when not only the metal has made various studies also wood lacquered furniture or the like, it seems to be utilized to remove the lacquer without surface damage.

Development of PVY resistant flue-cured $F_1$ hybrid variety 'KF120'

  • Kim, Jae-Hyun;Park, Yong-Hack;Chung, Youl-Young;Kim, Kwang-Chul;Shin, Seung-Gu;Kuem, Wan-Soo
    • Journal of the Korean Society of Tobacco Science
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    • v.31 no.2
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    • pp.69-74
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    • 2009
  • Potato Virus Y (PVY), PVY-vein necrosis strain, causes severe damage at growth, yield and leaf quality on flue-cured tobacco in Korea. The development of PVY resistant flue-cured varieties without quality deterioration is therefore urgently desired. The flue-cured tobacco, KF120 (Korea Flue-cured 120), was a male-sterile (ms) $F_1$ hybrid derived from the cross between msKF117 and KF0007-7. msKF117 was developed from the cross of NC82 with N. africana and KF0007-7 was developed from the cross of KF117 with NC82. The agronomic characteristics and disease resistance of KF120 was evaluated during 2006-2007 field performance test. It showed better growth characteristics and yield performance than standard cultivar KF109. It had 2 more leaves per plant, flowered 2 days later than KF109. The yield of cured leaf of KF120 was increased by about 5% compared to KF109. The chemical composition and physical properties of the cured leaf of KF120 were as much acceptable as those of KF109. KF120 showed high resistance to PVY compared to KF109. It showed a similar mode of resistance to bacterial wilt and black shank as was found in KF109.

A Study about Restraint Use in Care of Patients with Psychiatric Disorders (일 정신병원에서 발생한 강박 처치에 관한 연구)

  • An, Hyo Ja;Kim, Eun Ha;Chung, Young Hae;An, Jung Sim;Cho, Won Ae;Park, Joung Hwa
    • Journal of Korean Clinical Nursing Research
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    • v.19 no.3
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    • pp.432-442
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    • 2013
  • Purpose: The purpose of this study was to describe restraint use in care of patients with psychiatric disorders in an attempt to avoid unnecessary restraint use and provide information for developing standards regarding restraint use as a therapeutic maneuver. Methods: For this descriptive study, discharge records from N National Mental Hospital in the year 2009 were reviewed by trained nurses during Dec. 24, 2010 and Mar. 31, 2011. There were 596 restrains applied on 232 of 1,322 discharges. Data collected include general characteristic of patients, the frequency of restraint use, time since admission when restraint was applied, time of the day when restraint was applied, duration of restraint application, place of occurrence, reasons for restraint use, and degree of damage to the patent. Work experience of nurses who applied restraints, number of workforce at the time of restraint, and season of the year was also identified. Descriptive statistics, Chi-square test, t-test, ANOVA, $Scheff{\grave{e}}$ and Jonckheere-Terpstra were applied using SPSS 14.0 to analyze the data. Results: There were 596 restraint uses among 232 patients. Restraints were applied most frequently on males in their 40s, patients diagnosed with schizophrenia, and patients repeating admissions more than 6 times. Restraints were frequently applied within first week following admission, between 16:00 and 20:00, and the average duration of restraint was 5 hours. There were significant differences according to diagnoses of patients in the season restraint occured, time, place of occurrence, reason for restraint, and duration of restraint. Patients with alcoholism received longer restraint application. Conclusion: In order to avoid unnecessary restraint use in patients with psychiatric disorders, nurses and other health care team members need to acknowledge a group of patients such as patients with schizophrenia and alcoholism who relatively frequently restrained or receiving longer restraint. Reasonable and careful decision need to be made when applying restraint in the care of patients with alcohol problem.

A GIS-Based Seismic Vulnerability Mapping and Assessment Using AHP: A Case Study of Gyeongju, Korea (GIS 기반 AHP를 이용한 지진 취약성 지도제작 및 평가: 경주시를 중심으로)

  • Han, Jihye;Kim, Jinsoo
    • Korean Journal of Remote Sensing
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    • v.35 no.2
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    • pp.217-228
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    • 2019
  • In this study, a seismic vulnerability map of Gyeongju city, where the 9.12 Gyeongju earthquake occurred, was produced and evaluated using analytic hierarchy process(AHP) and geographic information system (GIS). Geotechnical, physical, social, structural, and capacity factors were selected as the main indicators and 18 sub-indicators to construct a spatial database. Weights derived using the AHP were applied to the 18 sub-indicators, which generated a vulnerability map of the five main indicators. After weighting the five generated maps, we created seismic vulnerability maps by overlaying each of the five maps. The seismic vulnerability map was classified into five zones, i.e., very high, high, moderate, low, and safe. For seismic vulnerability, the results indicated that 3% of Gyeongju area is characterized as having very high vulnerability, while 19% was characterized as safe. Based on district standards, Jungbu-dong, Hwangoh-dong, Hwangseong-dong, Seonggeon-dong, and Dongcheon-dong were high-risk areas, and Bodeok-dong, Gangdong-myeon, Yangbuk-myeon, Yangnam-myeon, and Oedong-eup were characterized as safe areas. The seismic vulnerability map produced in this study could possibly be used to minimize damage caused by earthquakes and could be used as a reference when establishing policies.

Study on Development of Export Packaging for Fresh Melon (신선 멜론의 수출포장개발에 관한 연구)

  • Lee, Myung-Hoon;Jung, Jun-Jae
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.15 no.3
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    • pp.83-91
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    • 2009
  • It is very difficult to export the fresh agricultural products to long distance countries such as USA and EU without any damage. Fresh products exporting would overcome very severe conditions such as hot and cold weather changes, heavy vibrations with rolling and pitching during the target distribution period, therefore, the packaging needs the immobility of products in the container and the keeping its quality by packaging materials or methods under any surrounding environments, especially. The physical strength of outer box should be designated according to its own characteristics for agricultural product packaging. Packaging dimension which would be fit to standard pallet is also very important factor to reduce the distribution cost. There have been many agricultural products researches for export packaging to the USA so far. However they have never got desirable results which enough to apply it in real. The main purpose of this research is to develop optimum compressive strength and optimum dimension of corrugated fiberboard box which would be used to USA export packaging of fresh melon as well as Japan.

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Effectiveness of Three Commercial Wood Preservatives against Termite in Korea (주요 국내 사용 방부제 3종에 대한 흰개미 저항 효력)

  • Lee, Hansol;Hwang, Won-Joung;Lee, Hyun-Mi;Son, Dong-Won
    • Journal of the Korean Wood Science and Technology
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    • v.43 no.6
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    • pp.804-809
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    • 2015
  • Since Korea is home to Reticulitermes speratus, a kind of subterranean termites that prefer dark and humid conditions, there have been increasing damages to wooden structures by termites. One noticeable attribute of Korean subterranean termites is that they prefer than Pinus densiflora, the major construction material for Korean traditional houses. And because wide varieties of termites are distributed all over the world, it is not so easy to choose appropriate control methods depending on specific areas. This necessitates careful applications of the following control methods depending on the kinds of termites: fumigation treatment, soil termiticide, preservatives and insect treatment, termite colony elimination system, chemical treatment, and other physical and biological treatment methods. The purpose of this study is to investigate the control effects of environmentally-friendly Alkaline copper quaternary (ACQ), Copper Azole (CuAZ) and Micronized copper quarter (MCQ) on the termites contributing to the damage of wooden structures. It was found in this study that wood with preservative treatment produced a significantly higher termicidal efficacy than untreated wood.

Analysis of the Vulnerability of the IoT by the Scenario (시나리오 분석을 통한 사물인터넷(IoT)의 취약성 분석)

  • Hong, Sunghyuck;Sin, Hyeon-Jun
    • Journal of the Korea Convergence Society
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    • v.8 no.9
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    • pp.1-7
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    • 2017
  • As the network environment develops and speeds up, a lot of smart devices is developed, and a high-speed smart society can be realized while allowing people to interact with objects. As the number of things Internet has surged, a wide range of new security risks and problems have emerged for devices, platforms and operating systems, communications, and connected systems. Due to the physical characteristics of IoT devices, they are smaller in size than conventional systems, and operate with low power, low cost, and relatively low specifications. Therefore, it is difficult to apply the existing security solution used in the existing system. In addition, IoT devices are connected to the network at all times, it is important to ensure that personal privacy exposure, such as eavesdropping, data tampering, privacy breach, information leakage, unauthorized access, Significant security issues can arise, including confidentiality and threats to facilities. In this paper, we investigate cases of security threats and cases of network of IoT, analyze vulnerabilities, and suggest ways to minimize property damage by Internet of things.

Sensitivity Analysis of Drought Impact Factors Using a Structural Equation Model and Bayesian Networks (구조방정식모형과 베이지안 네트워크를 활용한 가뭄 영향인자의 민감도 분석)

  • Kim, Ji Eun;Kim, Minji;Yoo, Jiyoung;Jung, Sungwon;Kim, Tae-Woong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.1
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    • pp.11-21
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    • 2022
  • Drought occurs extensively over a long period and causes great socio-economic damage. Since drought risk consists of social, environmental, physical, and economic factors along with meteorological and hydrological factors, it is important to quantitatively identify their impacts on drought risk. This study investigated the relationship among drought hazard, vulnerability, response capacity, and risk in Chungcheongbuk-do using a structural equation model and evaluated their impacts on drought risk using Bayesian networks. We also performed sensitivity analysis to investigate how the factors change drought risk. Overall results showed that Chungju-si had the highest risk of drought. The risk was calculated as the largest even when the hazard and response capacity were changed. However, when the vulnerability was changed, Eumseong-gun had the greatest risk. The sensitivity analysis showed that Jeungpyeong-gun had the highest sensitivity, and Jecheon-si, Eumseong-gun, and Okcheon-gun had highest individual sensitivities with hazard, vulnerability, and response capacity, respectively. This study concluded that it is possible to identify impact factors on drought risk using regional characteristics, and to prepare appropriate drought countermeasures considering regional drought risk.