• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.26.1-26.1
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• 2009

최근 반도체 세정에 있어서 지난 40년 동안 지속적으로 사용되고 있는 알칼라인 기반의 RCA 세정법은 많은 초순수 및 화학액 소모량과 세정시 불필요한 박막의 손실, 환경적인 문제로 인하여 이를 대체하고자 하는 새로운 새정액 및 세정 방법에 대한 연구가 활발하게 이루어지고 있다. 특히 초순수에 가스를 혼합하여 메가소닉을 이용한 기능수 세정은 기존 RCA 세정액의 문제점들을 해결하기 위한 세정액으로 최근 반도체 제조 공정 뿐만 아니라 Photo mask, FPD 세정 공정에서 널리 이용되고 있다. 하지만 기능수에 대한 기초적인 특성 연구와 메가소닉에 의한 세정력 변화에 대한 연구는 부족한 상태이다. 본 연구에서는 고순도의 수소가스(99.999%)를 가스 접촉기, pHasorII (Entigris, USA) 와 순환 속도의 조절이 가능한 펌프, BPS-3 (Levitronix, USA) 를 이용하여 지속적으로 초순수와 수소가스를 혼합하는 방법으로 수소수를 제조하였으며, 용존 수소 농도계, DHDI-1 (TOA-DKK, Japan)으로 수소수의 농도를 확인하였다. 0.1 MPa 압력과, 3 LPM의 수소가스 유출속도에서 최대 2.0 ppm의 수소수를 얻을 수 있었으며, 수소수의 기초 특성을 평가하기 위하여 수소 농도 변화에 따른 pH, 표면 에너지를 측정하였다. 또한 압력 변화에 따른 반감기를 측정하여 bath형태의 세정기에서 적용 가능성을 평가하였다. 수소수의 세정력은 $Si_3N_4$ 입자가 임의로 오염된 실리콘 웨이퍼를 이용하여 bath 및 매엽식 세정기에서 수소수 농도와 메가소닉 형태 및 첨가제 변화에 따른 세정효율을 기존의 SC-1 세정액과 각각 비교 평가하였다. 기능수 발생장치에서 압력이 제거된 상태에서는 평균 20분의 반감기를 갖는 것이 관찰되었고, 압력이 유지된 상태에서는 수소수의 농도가 유지되는 것을 확인하였으며, pH의 경우 수소수의 농도가 점차 증가함에 따라 감소하여 2.0 ppm의 농도에서 pH 5.3정도의 값을 나타내었다. 표면 장력은 초순수와 비교했을 때 큰 변화가 없음을 확인할 수 있었다. Bath 형태의 세정기에서 메가소닉을 인가하여 수소수의 세정효율을 측정한 결과, 같은 조건에서 실험한 초순수와는 비슷하며, SC-1보다는 낮은 세정효율이 측정되었다. 반면 매엽식 세정기에서 동등한 조건의 실험을 실시한 결과, 수소수 세정에서 첨가제에 의한 영향으로 SC-1을 대체할 수 있는 높은 입자 제거효율을 가짐을 확인할 수 있었다.

• Elastomers and Composites
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• v.47 no.4
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• pp.355-363
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• 2012

A series of poly(hydroxyamide)s (PHAs) having trifluoromethyl group were prepared by direct polycondensation of aromatic diimide-dicarboxylic acids with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane by thionyl chloride and triethyl amine in N-methyl-2-pyrrolidinone (NMP). The PHAs exhibited inherent viscosity in the range of 0.54-0.96 dL/g at $35^{\circ}C$ in DMAc solution. All PHAs were readily soluble in a variety of organic solvents, whereas the polybenzoxazoles (PBOs) were quite insoluble except partially soluble in sulfuric acid. PHAs were converted to PBOs by thermal cycling reaction with heat of endotherm. The maximum weight loss temperature of the PHAs occurred in the range of $559-567^{\circ}C$. The PBOs showed relatively high char yields in the range of 47-59%. Pyrolysis Combustion Flow Calorimeter (PCFC) results of the PBOs showed 12-19 W/g heat release rate (HRR), and 2.7-3.6 kJ/g total heat release (total HR). The HRR of PBO 1 showed the lowest value of 12 W/g, which was 37% lower than that of PBO 3 (19 W/g).

• Journal of the Korean Ceramic Society
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• v.39 no.9
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• pp.846-850
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• 2002

A PMN-PT-BT/Ag composite was prepared by surface modification with MgO sol with hoping to suppress silver's migration during sintering. The mixture of PbO, $N_2O_5,\;TiO_2\;with\;Mg(NO_3)_2$ instead of MgO was ball milled, the solvent was removed and then the dried powders were calcined at 950$^{\circ}C$/1h. The calcined powder were treated with 3.0 mol% $Ag_2O$ and 1.0 wt% MgO sol and calcined at 550$^{\circ}C$/1h. The dielectrics sintered at 1000$^{\circ}C$/4h under a flowing oxygen showed the density of 7.84g/$cm^3$, the room temperature dielectric constant of 18400, the dielectric loss of 2.4%, the specific resistivity of $0.24{\times}10^{12}{\Omega}{\cdot}cm$. It also showed the bending strength of $120.7{\pm}11.26$ MPa and the fracture toughness of $0.87{\pm}0.002\;MPam^{1/2}$ which were comparable to commercial PZT. The microstructure sonsisted of grains of ∼4${\mu}m$. SEM and SIMS analysis showed that Ag grew as ∼1${\mu}m$ and excess MgO as ∼0.5${\mu}m$.

• Journal of the Society of Disaster Information
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• v.8 no.4
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• pp.362-375
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• 2012

Tourist hotels are equipped with facilities such as accommodation and restaurants, exercise, recreation. Unspecified guests, visitors and management of tourist hotels are very vulnerable on the casualties and property losses due to fire peril exist. In this study, we analysis that the fire statistics status of tourist hotels from 2001 to 2010. And the 15 cases of a large hotel fire are reviewed. The total number of fires on hotel are consist of a hotel rooms fire(33.2%), a restaurant kitchen fire(11.8%). And the major causes of the fire are an electrical fire (40.8%), a cigarette fire (14.5%) and a hot-work fire (9.2%). In case study, the fire wall defect and combustible materials are major fire loss causes for 10year. Each tourist hotels are needed a development of suitable fire risk management and a field operations. A hotel is required an active fire risk management on a preventive inspection, an education and training, and a preventive maintenance. It is necessary that a fire wall maintenance to prevent of the spread of a fire and a sprinkler installation of whole area to protect fire. And it is very important an emergency response for evacuation of guest, and operate emergency procedures on a fire or emergency situation.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.205-205
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• 2013

테라헤르쯔(terahertz: THz)파는 0.1~10 THz 의 범위로 적외선과 방송파 사이에 광대역 주파수 스펙트럼을 차지하고 있으며 직진성, 투과성, 그리고 낮은 에너지 (meV)를 가지고 있어 비 파괴적이고 무해한 장점을 지니고 있다. Ti:sapphire laser와 같은 femto-pulse source 등이 많은 발전이 되어 현재 많은 연구와 발전이 이루어지고 있다. femto-pulse source를 이용한 THz 응용에서는 높은 저항, 큰 전자 이동도, 그리고 아주 짧은 전하수명의 기판을 요구하는데 저온에서 성장한 (low-temperature grown : LT) GaAs는 격자 내에 Gallium 자리에 Arsenic이 치환 하면서 AsGa antisite가 발생하여 전하수명을 짧아지는 것을 응용하여 가장 많이 이용되고 있다. 현재 THz 응용분야에서 보다 작고 가격경쟁력이 있는 광통신을 이용한 THz photomixer등이 활발히 연구 하고 있다. 광섬유 내에서 손실과 분산이 최소값을 가지는 부분이 1.55 ${\mu}m$ 부근이고 In0.53Ga0.47As 기판을 이용하였을 때 여기에 완벽하게 만족하게 된다. 하지만 LT-InGaAs 의 경우 AsGa antisite로 인하여 carrier lifetime은 짧아지지만 높은 n-type 전하밀도를 가지게 된다. 이때 Be을 doping하여 전하밀도를 보상하여 높은 저항을 유지해야 하는데 Be의 활성화를 위해서는 열처리를 필요로 한다. 하지만 열처리를 하면 carrier lifetime이 길어지기 때문에 carrier lifetime과 저항을 적절히 조율해야 한다. 이는 물질자체의 특성이기 때문에 InGaAs는 GaAs보다 낮은 amplitude와 짧은 cut-off frequency를 가진다. 본 연구에서는 보다 높은 저항을 얻기 위하여 molecular beam epitaxy를 이용하여 semi-insulating InP:Fe 기판위에 격자 정합된 InGaAs:Be/InAlAs multi quantum well (MQW)를 온도별 ($250{\sim}400^{\circ}C$), 주기별 (50~150)로 성장을 하였고 이때 InGaAs layer의 Be doping level은 $2{\times}1018\;cm^{-3}$, Ex-situ annealing은 $550^{\circ}C$에서 10분으로 고정 하였다. THz 발생 실험에서는 InGaAs/InAlAs MQW은 4000 pA로 1,000 pA를 가지는 InGaAs epilayer보다 4배 높은 전류 신호를 얻을 수 있었고 모든 샘플이 2 THz에서 cut-off frequency를 가지고 있었다. THz 검출 실험에서는 LT-InGaAs:Be epilayer LT-InGaAs:Be/InAlAs, HT-InGaAs/InAlAs 샘플이 각각 180, 9000, 12000 pA의 전류신호를 가지고 있었고 모든 샘플이 2 THz에서 cut-off frequency를 가지고 있었다. HT-InGaAs/InAlAs MQW를 이용한 검출실험에서는 InGaAs layer가 defect free이지만 LT-InGaAs:Be/ InAlAs MQW 보다 높은 전류 신호를 얻을 수 있었다. 이는 InAlAs layer가 저항만 높이는 것뿐만 아니라 carrier trapping layer로써의 역할도 하는 것으로 사료된다.

• Korean Journal of Construction Engineering and Management
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• v.9 no.3
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• pp.153-163
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• 2008

Domestic construction industry accounts about 15% of Gross Domestic Product(GDP) and Korean government spends approximately 50 trillion won per year for public infrastructure projects. Effective management of public construction projects would result in cost saving and enhance financial stability of the government. In doing so, the government promoted a new budgeting system, Continual Budget Method(CBM) as a part of public project performance enhancement program published in 1999. This research mainly attempted to investigate and analyze the impact of new budgeting in term of cost and schedule performance. Based on the analysis result of n2 projects. The new budgeting system could save project cost by 9.83y. Due to the saving of indirect costs from reduction. Although limited government budget cannot allow all the projects to be excuted with the new budgeting system, the new budgeting system should be more-widely utilized in the public sector because of its proven benefits from this research.

• Journal of Korean Medicine Rehabilitation
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• v.33 no.4
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• pp.15-29
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• 2023

Objectives The purpose of this study is to systematically review the effects of Neuromuscular Electrical Stimulation treatment on muscle wasting in cancer patients. Methods Randomized controlled trials (RCTs) were searched from seven online databases (PubMed, Cochrane Library, EMBASE, China National Knowledge Infrastructure, Oriental Medicine Advanced Searching Integrated System, Korean studies Information Service System, Research Information Sharing Service. The selected RCTs were evaluated for methodological quality through the Cochrane RoB. Results A total of 126 articles were identified, and 4 randomized controlled trials were selected for systematic review. In one study, it was found that there were statistically significant improvements in the Health-Related Quality of Life (FACTH&N total score, p<0.001). Additionally, significant effects were observed in measurements that represented the size of the quadriceps muscle (cross-sectional area of Vastus lateralis and Rectus femoris, p=0.004), maximum muscle strength, the twitch response of resistance muscles, and voluntary activation (p<0.001). However, no significant differences were observed between the intervention and control groups in terms of quadriceps muscle strength in two other studies (p>0.05). Lastly, while one study showed no significant differences in muscle fiber characteristics between the two groups, it did report significant improvements in measurements related to mitochondria within muscle tissue and muscle strength in the intervention group (p<0.05). Conclusions Neuromuscular electrical stimulation can be a method used to improve muscle strength in muscle wasting of cancer patients, but it is difficult to see its effects as significant compared to other treatments.

• Journal of Wetlands Research
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• v.25 no.1
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• pp.35-47
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• 2023

Korean facility horticulture and hydroponic cultivation methods increase, requiring the management of waste water generated. In this study, the amount of fertilizer contained in the discharged waste liquid was determined. By evaluating this as a price, it was suggested to reduce water treatment costs and recycle fertilizer components. It was evaluated based on the results of major water quality analysis of waste liquid by crop, such as tomatoes, paprika, cucumbers, and strawberries, and in the case of P component, it was analyzed by converting it to the amount of phosphoric acid (P₂O₅). The amount of nitrogen (N) can be calculated by discharging 1,145.90kg·ha^-1 of tomatoes, 920.43kg·ha^-1 of paprika, 804.16kg·ha^-1 of cucumbers, 405.83kg·ha^-1 of strawberries, and the fertilizer content of P₂O₅ is 830.65kg·ha^-1 of paprika, 622.32kg·ha^-1 of tomatoes, 477.67kg·ha^-1 of cucumbers. In addition, trace elements such as potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and manganese (Mn) were also analyzed to be emitted. The price per kg of each item calculated by averaging the price of fertilizer sold on the market can be evaluated as KRW, N 860.7, P 2,378.2, K 2,121.7, Ca 981.2, Mg 1,036.3, Fe 126,076.9, Mn 62,322.1, Zn 15,825.0, Cu 31,362.0, B 4,238.0, Mo 149,041.7. The annual fertilizer loss amount for each crop was calculated by comprehensively considering the price per kg calculated based on the market price of fertilizer, the concentration of waste by crop analyzed earlier, and the average annual emission of hydroponic cultivation. As a result of the analysis, the average of the four hydroponic crops was 5,475,361.1 won in fertilizer ingredients, with tomatoes valued at 6,995,622.3 won, paprika valued at 7,384,923.8 won, cucumbers valued at 5,091,607.9 won, and strawberries valued at 2,429,290.6 won. It was expected that if hydroponic drainage is managed through self-treatment or threshing before discharge rather than by leaking it into a river and treating it as a pollutant, it can be a valuable reusable fertilizer ingredient along with reducing water treatment costs.

• Culinary science and hospitality research
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• v.22 no.3
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• pp.11-21
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• 2016

This study investigated the quality characteristics and retarding retrogradation of sponge cakes made with red yeast rice (RYR) flour. RYR (Monascus nuruk) is known to help digestion, smooth blood flow, and have anti-cancer, anti-microbial, and inhibitory effects against biosynthesis of cholesterol and blood pressure. This studys aim' was to find the optimal proportion of RYR flour in sponge cake. RYR sponge cakes were prepared with various levels (0, 5, 10, 15 and 20%) replacement of wheat flour and were designated as the control (without RYR), RYR5, RYR10, RYR15 and RYR20 respectively. Specific gravity was the lowest in RYR15 at 0.57, and the baking loss rate was not significantly different among the samples (p<0.05). The dough yield was the highest in RYR15 at 96.61. The moisture contents was highest in order, control, RYR5, and RYR15 at 28.67%, 28.18%, and 26.82% respectively. The L-value of crust tended to increase according to the level of RYR, but the L-value of crumb decreased in accorddance with the the content of RYR. The a-value of crust also decreased according to the level of RYR, although the a-value of crumb increased in response to higher levels of RYR. The b-value tended to decrease with increases of RYR (p<0.05). RYR5 exhibited the highest pH at 8.63, compared with RYR15 (8.57). The hardness, which was measured after cooling for 1 hour, was the lowest in RYR15 at $163.33g/cm^2$ and the springiness was not different significantly (p<0.05). Cohesiveness was the highest in RYR10 at 133.06%. The chewiness was the highest in RYR10 at $391.63g{\cdot}cm$ and lowest in RYR15 ast $169.62g{\cdot}cm$. Avrami equation showed that RYR15 and RYR20 had the lowest Avrami exponent (n) at 0.0664 and 0.4983 respectively. Time constant (1/k) was the highest in RYR15 at 200.00. Sensory evaluation revealed that RYR15 was the highest in color (5.50), flavor (4.95), sweetness (4.90), chewiness (4.75), and overall acceptability (4.60).

• Journal of Intelligence and Information Systems
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• v.23 no.1
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• pp.143-159
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• 2017

Due to the rapid development of IT in recent years, not only personal information but also the key technologies and information leakage that companies have are becoming important issues. For the enterprise, the core technology that the company possesses is a very important part for the survival of the enterprise and for the continuous competitive advantage. Recently, there have been many cases of technical infringement. Technology leaks not only cause tremendous financial losses such as falling stock prices for companies, but they also have a negative impact on corporate reputation and delays in corporate development. In the case of SMEs, where core technology is an important part of the enterprise, compared to large corporations, the preparation for technological leakage can be seen as an indispensable factor in the existence of the enterprise. As the necessity and importance of Information Security Management (ISM) is emerging, it is necessary to check and prepare for the threat of technology infringement early in the enterprise. Nevertheless, previous studies have shown that the majority of policy alternatives are represented by about 90%. As a research method, literature analysis accounted for 76% and empirical and statistical analysis accounted for a relatively low rate of 16%. For this reason, it is necessary to study the management model and prediction model to prevent leakage of technology to meet the characteristics of SMEs. In this study, before analyzing the empirical analysis, we divided the technical characteristics from the technology value perspective and the organizational factor from the technology control point based on many previous researches related to the factors affecting the technology leakage. A total of 12 related variables were selected for the two factors, and the analysis was performed with these variables. In this study, we use three - year data of "Small and Medium Enterprise Technical Statistics Survey" conducted by the Small and Medium Business Administration. Analysis data includes 30 industries based on KSIC-based 2-digit classification, and the number of companies affected by technology leakage is 415 over 3 years. Through this data, we conducted a randomized sampling in the same industry based on the KSIC in the same year, and compared with the companies (n = 415) and the unaffected firms (n = 415) 1:1 Corresponding samples were prepared and analyzed. In this research, we will conduct an empirical analysis to search for factors influencing technology leakage, and propose an early warning system through data mining. Specifically, in this study, based on the questionnaire survey of SMEs conducted by the Small and Medium Business Administration (SME), we classified the factors that affect the technology leakage of SMEs into two factors(Technology Characteristics, Organization Characteristics). And we propose a model that informs the possibility of technical infringement by using Support Vector Machine(SVM) which is one of the various techniques of data mining based on the proven factors through statistical analysis. Unlike previous studies, this study focused on the cases of various industries in many years, and it can be pointed out that the artificial intelligence model was developed through this study. In addition, since the factors are derived empirically according to the actual leakage of SME technology leakage, it will be possible to suggest to policy makers which companies should be managed from the viewpoint of technology protection. Finally, it is expected that the early warning model on the possibility of technology leakage proposed in this study will provide an opportunity to prevent technology Leakage from the viewpoint of enterprise and government in advance.