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        검색결과 170

        41.
        2004.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A new display device is required, which has concepts of flatness and slimness. FED can be one of the solutions. When we use flat panel, we can save the raw material and reduce the production time by eliminating the printing process, drying process, and wa
        4,000원
        43.
        2003.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 오이와 토마토의 플러그 묘 공정육묘시 발생하는 도장 억제를 위한 적생광 처리시기와 광도의 영향을 알아보기 위해 실험을 수행하였다. 일몰 휴, 야간 및 일출 전 적색광 처리시기에 의한 묘의 도장억제는 일몰 후 처리가 오이와 토마토의 초장을 각각 21.3%와 14.2%로 가장 크게 억제하였고, 경경의 굵기도 가장 두꺼웠다. 엽록소함량은 토마토에서만 일몰 후 처리된 플러스묘의 함량이 대조구에 비해 유의적으로 높게 나타났다. 적색광 초리시기에 의한 두 작물의 건물중을 보면, 대조구에 비해 지상부 건물중은 일몰 후와 일출 전 적색광 처리에 의해 유의적인 감소를 보였다. 오이와 토마토 플러그묘의 T/R율은 일몰 후 처리에서 타 처리에 비해 가장 작았으며 조ㅈ직의 충실도는 밀몰 후 처리에서 가장 크게 나타났다. 광도별 처리에 의한 초장은 오이와 토마토 플러그묘 모두에서 광도가 증가함에 따라 초장은 감소하였다. 하배출, 절간장 및 엽면적도 초장과 유사한 경향을 나타내었다. 두 작물 모두 경경과 엽록소함량 및 조직의 충실도는 광도가 증가함에 따라 증가하는 경향을 보였다. 하지만 지상부와 지하부의 건물율은 광도의 증가에 따라 감소하는 경향이 나타났으며, 오이는 2 및 8 μmol·m-2·s-1의 적색광 처리구에서 토마토는 8 μmol·m-2·s-1처리구에서 가장 낮은 T/R율을 나타내었다.
        4,000원
        44.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 공정육묘시 triazole계 약제처리가 과채류의(토마토, 오이 및 고추) 묘 도장억제에 미치는 영향을 구명하고, 도장억제에 가장 효과적인 약제를 선발하며, 또한 선발된 약제의 과채류 적정 처리농도와 처리시기를 구명하고자 수행하였다. Triazole계 약제는 품목과 관계없이 농도가 증가할수록 줄기 신장을 억제시켰다. 약제 별 품목별로 diniconazole 처리가 높은 왜화율을 보였으며, tebuconazole과 hexaconazole도 좋은 왜화 효과를 보였다. Diniconazole 처리에 있어서 처리 농도가 증가함 따라 오이, 토마토 및 고추의 초장이 감소하였는데, 오이의 경우 5mg·L-1 에서 30% 왜화율을 보였으며 100mg·L-1 에서는 약 60% 의 왜화율이 나타났다. 또한 토마토와 고추에서는 처리시 기와 관계없이 25mg·L-1 처리구서 3096 왜화효과를 보았다. 공정육묘시 diniconazole 처리를 할 경우 오이 와 토마토는 5mg·L-1 농도를 2차 생육단계에서, 고추는 5mg·L-1 농도를 1차 생육단계에서 처리하면 건실한 묘를 얻을 수가 있었다.
        4,000원
        45.
        2003.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Manual tracking is an experimental paradigm that can be used to study information processing in continuous movements involving accurate, ongoing control of motor performance. The purpose of this study was to identify the effects of knee tracking training, using the paretic side, on gait in stroke patients. Nine patients with hemiplegia participated in the study. The timed 10 m gait speed test and tracking test were administrated. The tracking test was composed with ranges of to and to . The tracking training consisted of five times every week for 4 weeks. The data were analyzed by non-parametric paired sign test of Wilcoxon. The flexion/extension error of the tracking test was significantly reduced on the paretic side, while the nonparetic side was not statistically significant. The transfer of the skill to the functional activity was shown in the significant improvement at timed 10 m gait speed test. This study shows that individuals with chronic who have impaired knee movement can be trained to improve their knee control through intensive practice at a knee movement tracking task and that the skill learned from such training is transfered to a more functional gait speed.
        4,000원
        46.
        2002.05 구독 인증기관 무료, 개인회원 유료
        It is the basic requirement of product characteristics to specify geometric dimensions and tolerances during design process of parts assembly. Therefore, there are many tolerance stack analysis method to explain tolerance zone. Tolerance stack analysis is to calculate gap using tolerances which includes geometric and coordinate dimension. In this study, we compared several different stack analysis method and try to suggest more general method called the Virtual Method to analyze tolerance stack.
        4,000원
        47.
        2001.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the era of digital technology, display device is the one of the important interface tool to communicate and transmit the information. Among the various display devices, CRT is the most popular one. Even though the CRT has many advantages comparing to other devices, it is faced to overcome its a few disadvantages especially in volume, shape and price, etc, In this paper, we try to show the development strategy of CRT corresponding with flat displays in the view point of ergonomics.
        4,000원
        48.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        50.
        2018.11 KCI 등재 서비스 종료(열람 제한)
        Shape memory materials are widely used in high-tech industries. Although shape memory polymers have been developed, they have a disadvantage, only unidirectional resilience. Shape memory polymers with bi-directional recovery resilience have been actively studied. In this study, a bidirectional shape memory polyurethane was synthesized using poly(ε-caprolactone) diol, methylene dicyclohexyl diisocyanate, and hydroxyethyl acrylate. The first physical curing occurred between hard segments and hydrogen bondings when the solution was dried. The second curing in acrylate groups was performed by UV exposure. A degree of curing was analyzed by infrared spectroscopy. The shape memory properties of 2 step-cured polyurethanes were investigated as a function of UV curing time.
        51.
        2018.10 KCI 등재 서비스 종료(열람 제한)
        In the industrial wastewater that occupies a large proportion of river pollution, the wastewater generated in textile, leather, and plating industries is hardly decomposable. Though dyeing wastewater has generally been treated using chemical and biological methods, its characteristics cause treatment efficiencies such as chemical oxygen demand (COD) and suspended solids (SS) to be reduced only in the activated sludge method. Currently, advanced oxidation technology for the treatment of dyeing wastewater is being developed worldwide. Electro-coagulation is highly adapted to industrial wastewater treatment because it has a high removal efficiency and a short processing time regardless of the biodegradable nature of the contaminant. In this study, the effects of the current density and the electrolyte condition on the COD removal efficiency in dyeing wastewater treatment by using electro-coagulation were tested with an aluminum anode and a stainless steel cathode. The results are as follows: ① When the current density was adjusted to 20 A/m2, 40 A/m2, and 60 A/m2 under the condition without electrolyte, the COD removal efficiency at 60 min was 62.3%, 72.3%, and 81.0%, respectively. ② The removal efficiency with NaCl addition was 7.9% higher on average than that with non-addition at all current densities. ③ The removal efficiency with Na2SO4 addition was 4.7% higher on average than that with non-addition at all current densities.
        52.
        2018.06 KCI 등재 서비스 종료(열람 제한)
        In this study, using coke dust from ironwork, the pulse pressure on a pulse air jet bag filter was investigated considering the influence of the pressure loss due to filtration velocity and pressure intervals. The research on the optimal pulse pressure prediction of a pulse air jet type bag filter using coke dust showed the following results. Pressure loss volatility produced by the pulse pressure under low dust concentration(0.5, 1 g/m3) and low face velocity(1.25 m/min) was less than 10 mmH2O. This suggests that the pulse pressure has a low impact on the pressure loss. In contrast, pressure loss volatility under high dust concentration(3 g/m3) and high face velocity(1.75 m/min) was 25 mmH2O. Therefore, pulse pressure with high dust concentration and high face velocity has a strong influence on the pressure loss volatility, compared to the condition of low dust concentration and low face velocity. The optimal pulse pressure of inlet dust concentration(0.5 g/m3) was 6 kg/cm2 under the same face velocity(1.75 m/min). As concentration increased from 1 to 2 g/m3, the pulse pressure gradually reached 5 kg/cm2 thus indicating that the pulse pressure(5 kg/cm2) is pertinent at a high concentration(3 g/m3). The pulse intervals: 20, 25 and 30 sec, which are relatively longer than 10 and 15 sec, corresponded to high pressure loss volatility produced by the pulse pressure. Furthermore, low pressure loss volatility was noted at 5 kg/cm2 of the overall pulse pressure.
        53.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        The mother machine makes the necessary shape by processing materials such as metal. The SCFs are applied to the processing surface when the mother machine processes the material, thereby improving the cutting conditions. SCFs contain high concentrations of organic components and nitrogen compounds, which can cause problems such as eutrophication and algae bloom. Therefore, proper treatment is required. Electrochemical treatment is expected to be an alternative to conventional processes, and to be useful in various wastewater treatments. Moreover, it is an efficient elimination technique for contaminants and has a simple equipment composition. In this study, the removal efficiency of the T-N contained in the waste SCF using electrochemical treatment is analyzed. The electrode was made of titanium and iridium, made into a perforated metal sheet to prevent an imbalance of the sample concentration in the reactor. Experiments were conducted to examine the effects of current density and the concentration of the supporting electrolyte (NaCl, Na2SO4) on removal efficiency. In the cases with 60 A/m2, 80 A/m2, and 100 A/m2 current densities, the removal efficiencies of the T-N contained in the waste SCF were 51.03%, 68.83%, and 79.58%. Comparing between the addition and non-addition of NaCl, the removal efficiency with the addition of NaCl (5 ~ 10 mM) was higher than for no addition at 60 min for all current densities. The addition of Na2SO4 increased the removal rate of the T-N, but it was less effective than NaCl addition.
        54.
        2017.12 KCI 등재 서비스 종료(열람 제한)
        As industry continues to develop, the amount of various recalcitrant substances that cannot be removed by conventional wastewater treatment has increased in modern society. The SCFs (Soluble Cutting Fluids) used in metalworking processes contain many chemical substances, such as mineral oils, anticorrosive agents, extreme-pressure additives and stabilizers, as well as high concentrations of organics. Recently, electrolysis has been expected to become an alternative to conventional processes and to be useful in various wastewater treatments. Electrolysis is a highly adaptable industrial wastewater treatment method, having a high efficiency, short processing time, and simple equipment composition, regardless of the biodegradable nature of the contaminants. The effects of operating time, current density, and electrolyte on COD removal of waste SCFs have been studied using the stainless steel (SUS316) electrode in a batch type reactor. The results were as follows. ① Without electrolytes, when the current density was adjusted to 40 A/m2, 60 A/m2, and 80 A/m2, the removal efficiencies of the COD were 25.0%, 37.7%, and 49.1% after 60 min, respectively. ② In the comparison between NaCl (5 ~ 10 mM) addition and non-addition, the removal efficiency with NaCl was higher than for without after 60 min for all current densities. ③ In the comparison between Na2SO4 (5 ~ 10 mM) addition and nonaddition, the removal efficiency with Na2SO4 showed no significant difference to that with NaCl at all current densities.
        55.
        2017.11 서비스 종료(열람 제한)
        1970년대 수출주도 고도성장을 위해 정부는 조선・철강・기계 등의 중화학공업을 선택적으로 집중육성 하였다. 그 결과 일반기계산업은 1970년 수출 8백만불에서 2015년 현재 218,262백만불로 약 27,000배 이상 성장하였다. 일반기계산업에 있어 금속가공 공정은 필수적이며, 금속가공 공정에서 필요로 하는 것이 공작기계(Mother machine)와 절삭유(Soluble Cutting Fluids, SCF)이다. 절삭조건 개선에 사용되는 절삭유는 첨가제, 사용용도 등에 따라 원액으로 사용하는 비수용성과 물로 희석해서 사용하는 수용성으로 나뉜다. 국내 절삭유 이용량의 60%이상이 수용성 절삭유로 비수용성 절삭유의 오일미스트(Oil-mist), 폐유처리과정에서 유독성 물질 발생 등의 문제로 수용성 절삭유 사용량이 점차 증가하였다. 또한 절삭 성능 향상을 위한 방부제, 윤활제, 방청제, 부식방지제, 세정제, 극압 첨가제 등 각종 화학물질 첨가로 인해, 노출될 경우 췌장, 피부, 담낭, 방광, 소화기계 등 인체의 여러 조직에 암을 유발할 수 있으며, 각종 호흡기계 질환과 피부질환을 초래하는 것으로 알려져 있다. 인체에 미치는 영향 외에도 수용성 절삭유에는 고농도의 유기성분과 질소화합물 등이 함유되어 있어 적절한 처리 없이 수계로 유출시 부영양화, 녹조현상 등과 같은 문제를 일으킬 수 있으며 산화반응에 의해 수계의 용존산소를 감소시키므로 그 처리의 중요성이 부각되고 있다. 본 연구에서는 실공정에서 발생한 폐수용성절삭유를 원시료로 하여 대표적인 불용성 전극인 Ti/IrO2 전극을 이용하여 전기화학적 처리를 진행하였으며 연구에 사용한 장치의 모식도를 Fig. 1에, 시료의 성상을 Table 1에 나타내었다.
        56.
        2017.11 서비스 종료(열람 제한)
        우리나라 경제의 성장을 이끈 기계산업은 2015년 현재 생산액 100조원, 사업체수 9,526개사, 종사자수 31만 5천명, 부가가치 39조원으로써 제조업 중 생산액 5위, 사업체수 2위, 종사자수 3위, 부가가치 4위에 위치하고 있다. 이러한 기계산업에 있어 공작기계를 이용해 금속을 원하는 모양으로 만드는 금속가공은 반드시 필요한 공정으로 금속가공 시 가공 장비의 수명 연장 및 가공물의 품질 향상을 위해 칩이 형성되는 영역에 적용되어 윤활 및 냉각작용을 하는 절삭유(Soluble Cutting Fluids, SCF)가 이용되고 있다. 절삭유는 수용성 및 비수용성으로 나뉘는데 비수용성 절삭유의 경우 윤활성은 우수하나 경제성 및 발연, 발화등의 문제점이 있으며, 수용성 절삭유는 윤활성은 비교적 떨어지나 냉각성과 경제성이 우수하다는 장점이 있다. 또한 절삭유는 기능 향상을 위해 PAH, 방부제, 파라핀계 염소, 아질산염 등 20~30개의 첨가제가 사용된다. 이는 중추신경계 장애, 이비인후 자극, 피부염 발생 등을 일으킬 위험성이 크다고 알려져 있으며, 고농도의 유기성분 및 질소화합물로 인해 수계에 유출시 부영양화, 녹조현상 등과 같은 문제를 일으킬 수 있다. 따라서 본 연구에서는 전기화학적 처리를 통해 반응시간에 따른 폐수용성 절삭유의 COD 및 T-N의 제거율 변화를 분석하였다. 전기화학적 처리의 중요 인자인 전극은 비교적 가격이 저렴하고 용출량이 낮은 것으로 알려져 있는 SUS316전극을 이용하였으며 자세한 실험 조건을 Table 1에, 연구에 사용한 장치의 모식도를 Fig. 1에 나타내었다.
        57.
        2017.10 KCI 등재 서비스 종료(열람 제한)
        Soluble Cutting Fluids (SCFs) have been used in metal machining processes to improve the quality of metal processing equipment and products. Although SCFs are useful and essential material, wasted soluble cutting fluids are harmful in hydroecological systems because of the high concentration of COD and nitrogen material. If discharged to hydroecological systems without specific treatment, they may cause eutrophication in rivers and lakes. Therefore, the removal efficiency of the COD contained in the SCFs is investigated in this study using electrochemical treatment with an insoluble electrode. The electrode was made of titanium with iridium plating, made from a perforated metal sheet to agitate the sample in the reactor. Cathode and anode electrodes were inserted into acrylic reactor alternately and the reaction time was one hour. The experimental results were as follows: First, for 60 A/m2, 80 A/m2, and 100 A/m2 current densities, the COD removal efficiencies were 42.0%, 63.9%, and 78.4%, respectively.
        58.
        2017.10 KCI 등재 서비스 종료(열람 제한)
        The use of Soluble Cutting Fluids (SCF) is essential in the development of industrial technology. However, it is difficult to decompose biologically due to its high concentrations of organic substances and nitrogen compounds, which interfere with microbial growth. Recently, Advanced Oxidation Processes are being studied both domestically and internationally. Electrolysis is highly adaptable industrial wastewater treatment because it has high removal efficiency and short processing time, regardless of the contaminant’s biodegradable nature. Accordingly, this study shows the characteristics of total nitrogen removal in SCF on the operating time, current density, and electrolytes when using aluminum in a batch-type reactor. The results are as follows: ① Under the condition of without the electrolyte when the current density was adjusted to 40 A/m2, 60 A/m2, or 80 A/m2, the respective T-N removal efficiencies were 71.7%, 80.6%, and 87.2% at 60 min. ② In the comparison for the condition of whether NaCl was added, the removal efficiency of adding NaCl (5 ~ 10 mM) was higher than non-addition at 60 min for all current densities. ③ In the comparison for the condition of whether Na2SO4 (5 ~ 10 mM) was added, the removal efficiency when adding Na2SO4 showed no significant difference compared to non-addition at 60 min for all current densities.
        59.
        2017.09 KCI 등재 서비스 종료(열람 제한)
        Soluble cutting fluids (SCFs) have been used in metal machining processes to improve the quality of metal processing equipment and products in modern society. Because the characteristics among metal machining processes differ, various types of cutting fluids are manufactured to enhance the cutting efficiency of different metals. Although SCFs are useful and essential materials, particular treatment is required attributable to the high concentration of nitrogen materials and chemical oxygen demand (COD). In this study, the removal efficiency of total nitrogen (T-N) contained in SCFs was analyzed using electrochemical treatment. The electrode was made of 316 stainless steel, which had been perforated to prevent an imbalanced sample concentration in the reactor. Cathodic and anodic electrodes were alternately inserted into an acrylic reactor. The removal efficiency of T-N in SCFs using 40 A/m2, 60 A/m2, and 80 A/m2 current density, was 48.2%, 61.5% and 69.3%, respectively. The removal efficiency of T-N in SCFs with the addition of 0, 5 mM, and 10 mM NaCl was 69.3%, 74.6%, 77.6%, respectively.
        60.
        2017.09 KCI 등재 서비스 종료(열람 제한)
        Based on the results of the prior study, we conducted a study of the DRE (destruction and removal efficiency) and carbonization of xylene using high electron beam energies. The irradiation intensity of electron beam energy was 30 mA, and the irradiation times were 5.7, 11.4, 22.8, and 45.6 sec. The absorbed dose were 124.23, 248.46, 496.91, and 993.83 kGy. Xylene was completely removed at 248.46 kGy, and the main by-products were carbon particles. Carbon particle formation was increased with increased absorbed dos. The carbon particles were generated as fine particles with a size of 0.5 to 1.0 μm. The most common oby-products of these particle were carbon black and graphite.
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