• Title/Summary/Keyword: 확산농도

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The Effect of Storage Container Types on Odor Emission and Quality of Piggery Liquid Slurry Fertilizer in the farms (농가의 돈분액비 저장형태가 악취발생과 액비품질에 미치는 영향)

  • Park, Moo-Eon;Kang, An-Seok;Kim, Si-Chang
    • Korean Journal of Soil Science and Fertilizer
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    • v.39 no.3
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    • pp.136-143
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    • 2006
  • The study was carried out to evaluate odor emission during storage time and quality of liquid slurry fertilizer along with three storage container types installed at farmer's fields in Cheorwon. Liquid slurry manure stored in the liquid-circulated or the air-injected tank was very homogeneous in concentration of nutritional elements because of well mixing operation, while nutritional concentration of the manure stored in the non-treated tank was significantly different from top to bottom in the tank, which may bring about partially irregular growth of plant after its application. The potential capacity of offensive odor emitted from liquid slurry manure stored in the liquid-circulated or the air-injected tank was much lower than that emitted from manure stored in the non-treated tank. Low potential capacity may less emit offensive odor after application of piggery liquid slurry on the field. The efficiency in oder to reduce odor emission from liquid manure was slightly higher in the liquid-circulated tank than the air-injected tank

Rheological Characteristics and Debris Flow Simulation of Waste Materials (광산폐석의 유변학적 특성과 토석류 흐름특성 분석)

  • Jeong, Sueng Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.4
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    • pp.1227-1240
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    • 2014
  • Abandoned mines often cause environmental problems, such as alteration of landscape, metal contamination, and landslides due to a heavy rainfall. Geotechnical and rheological tests were performed on waste materials corrected from Imgi waste rock dump, located in Busan Metropolitan City. Debris flow mobility was examined with the help of 1-D BING model which was often simulated in both subaerial and subaqueous environments. To determine flow curve, we used a vane-penetrated rheometer. The shear stress (${\tau}$)-shear rate (${\dot{\gamma}}$) and viscosity(${\eta}$)-shear rate (${\dot{\gamma}}$) relationships were plotted using a shear stress control mode. Well-known rheological models, such as Bingham, bilinear, Herschel-Bulkley, Power-law, and Papanastasiou concepts, were compared to the rheological data. From the test results, we found that the tested waste materials exhibited a typical shear shinning behavior in ${\tau}$-${\dot{\gamma}}$ and and ${\eta}$-${\dot{\gamma}}$ plots, but the Bingham behavior is often observed when the water contents increased. The test results show that experimental data are in good agreement with rheological models in the post-failure stage during shearing. Based on the rheological properties (i.e., Bingham yield stress and viscosity as a function of the volumetric concentration of sediment) of waste materials, initial flowing shape (5 m, 10 m, and 15 m) and yield stress (100 Pa, 200 Pa, 300 Pa, and 500 Pa) were input to simulate the debris flow motion. As a result, the runout distance and front velocity of debris flow are in inverse propositional to yield stress. In particular, when the yield stress is less than 500 Pa, most of failed masses can flow into the stream, resulting in a water contamination.

온라인 증권거래 서비스의 고객만족 요인에 대한 실증적 연구

  • Choe, Don-Hwang;Hong, Jae-Beom;Yang, Jeong-Sik
    • Proceedings of the Korea Association of Information Systems Conference
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    • 2005.05a
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    • pp.161-175
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    • 2005
  • 본 연구에서는 온라인 증권거래 서비스 품질과 고객만족 나아가 고객행동을 분석한 연구이다. 이를 위해 설문조사를 실시하였으며 조사원이 직접 증권사 객장을 방문하여 운라인 증권거래경험이 있는 고객을 대상으로 설문조사를 실시하였다. 이를 위해 40개 증권사, 420여개설문이 회수되었다. 분석결과, 첫째, 온라인 증권거래를 이용하는 고객층을 분석하면, 여성보다는 남성이 온라인 증권거래를 활발히 이용하고 있으며 연령별로는 40대, 50대, 30대 순으로 나타났으며 직업은 대부분 근로생활자가 많이 활용하고 있는 것으로 나타났으며 전체 50%이상이 매일 접속하고 거래하는 것으로 나타났으며 운영 규모는 1천만원이하가 다수로 나타났다. 둘째, 온라인 증권거래 서비스 품질요인으로 지각된 신뢰성, 지각된 편의성, 지각된 유형성, 지각된 응답성 순으로 고객만족에 영향을 미치는 것으로 나타났다. 지각된 신뢰성은 약속된 서비스를 정확하게 수행하는 능력에 대한 지각으로 나타내며, 지각된 편의성은 온라인증권거래를 이용하기에 얼마나 용이한 지에 대한 지각을 나타낸다. 지각된 유형성은 물적 시설, 장비, 사람, 의사소통 도구의 외형과 같은 부분에 대한 지각을 나타내는 것이다 지각된 응답성은고객을 돕고 즉각적인 서비스를 제공하려는 의지에 대한 지각을 나타낸다. 마지막으로 고객만족은 재이용이나 구전의도에 긍정적인 효과를 미치는 것으로 나타났다. 이러한 결과는 고객지향적인 온라인 증권거래 서비스 시스템 구축 및 운영이 이용확대에 중요한 요인임을 제시한다. 본 연구는 온라인 증권거래에 대한 고객만족의 탐색적인 연구로써 보다 심도 있는 연구를 위한 기초를 제공하였다는 점과 온라인 증권거래 성과측정요소로써 고객만족에 영향을 미치는 요인을 제시했다는 점에서 의미를 지닌다.에 의해 유도된 single-strand 절단을 억제하였다. 이상과 같이 간세포 일차배양에서 양파추출물은 t-BHP에 의해 유발된 간독성, 간세포 생존율 감소, 지질과산화를 농도 의존적으로 억제시켰고 또한 t-BHP에 의해 억제된 GSH-Px, GSH-Rd 및 catalase의 활성을 증가시켰다. 이와 같이 양파추출물의 간보호 및 항산화 효과는 항산화 효소, 특히 catalase의 활성 증가와 hydroxyl radical에 의해 유도된 산화억제 및 이에 따른 지질과산화 억제에 기인하는 것으로 사료된다.chno-economic paradigm)의 시각에서 제시하는 한국경제의 성장 ${\cdot}$ 고용 ${\cdot}$ 분배를 위한 정책방향은 다음과 같은 동태적발전과정으로 요약할 수 있다 : 기초과학연구능력 확충 ${\rightarrow}$ 소화 ${\cdot}$ 흡수 ${\cdot}$ 개량 ${\rightarrow}$ 토착화 능력의 배양 ${\rightarrow}$ 자체기술개발, 선진기술 도입, 산업간 및 산업내 기술확산, 국제기술협력 ${\rightarrow}$ 기술혁신의 촉진 ${\rightarrow}$ 총요소생산성과 기업경쟁력(자원 및 역량, 프로세스 경쟁력, 품질경쟁력, 시장경쟁력, 고객성과, 시장성과, 재무성과)의 제고 ${\rightarrow}$ 가격경쟁력(임금, 금리, 물류비용, 환율 등)과 비(非)가격경쟁력(디자인, 에프터서비스, 품질, 운송 등)의 제고 ${\rightarrow}$ 국가경쟁력의 제고 ${

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Electrochemical Study of the Effect of Additives on High Current Density Copper Electroplating (고전류밀도 구리도금에서 첨가제에 따른 전기화학적 특성변화 연구)

  • Shim, Jin-Yong;Moon, Yun-Sung;Lee, Jae-Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.18 no.2
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    • pp.43-48
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    • 2011
  • The maximum current density of copper electrorefining is 350 A/$m^2$ and the higher current density is required to promote the copper productivity. The 1000 A/$m^2$ high current density is possible when rotating disc electrode is employed to reduce diffusion thickness. The copper electroplating with 1000 A/$m^2$ is possible at 400 rpm. Thiourea and glue were used to improve the electrodeposition behaviors during copper electrorefining process. Potentiodynamic polarization tests were conducted to investigate the effects of additives on copper electrodeposition. Galvanostatic tests were also conducted at 1000 A/$m^2$. Copper were electroplated on cylindrical rotating electrodes to give the uniform flow on the electrode surface. The lowest surface roughness was obtained when 16 ppm thiourea was added to the electrolytes. The surface roughness was increased with glue concentration. The surface hardness was not influenced by addition of glue. The copper nuclei were getting smaller with thiourea concentration, however there is no glue effects on copper nucleation.

The Study on the Countermeasure Plans about Leakage, Explosion and Fire Accidents of Atmospheric Storage Tank (옥외저장탱크 누출, 폭발 및 화재사고 대응방안에 관한 고찰)

  • Lee, Gab-Kyoo
    • Fire Science and Engineering
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    • v.30 no.6
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    • pp.48-56
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    • 2016
  • A crude oil leakage from a large atmospheric storage tank occurred on 4 April 2014 at 14:50 in Ulsan City, while storing the crude oil in the tank. Emergency Rescue Control Group was deployed in the scene. The company, Fire Service Headquarters and associated agencies got together in Command Post (CP) for discussing an effective corresponding strategy. Many solution plans were drafted in the debate such as power down, stopping the facilities, checking the density of inflammable gas, suppressing oil evaporation, moving the leaked crude oil to a nearby tank and a processing plant and avoiding marine pollution. All the solutions were carried out in cooperation with several agencies and partners. The oil leakage accident was successfully settled up within the process of responding, The Fire Service Headquarters and the company thought that the most important thing was the suppression of oil evaporation and the elimination of ignition source. With Fire Service Headquarters and several agencies' every effort, an explosion and a fire didn't occurred in the scene. This study suggest the improvement of the operating system in Emergency Rescue Control Group in case of petroleum leakage, explosion and fire accidents of atmospheric storage tank, different from a ordinary disaster. Assuming that petroleum leakage in atmospheric storage tank develop the explosion and fire accidents, the spreading speed of the flame and the burning time was experimented and compared with each other. Furthermore, this study concentrates on the effective field response plan prepared for the afterward explosion and fire accidents from petroleum leak in a storage tank, with the database experimented and analyzed in accordance with the angle of radiation in the foam nozzle and the pressure of pumping in a fire engine.

Air Quality Monitoring System Using NDIR-CO$_2$ Sensor for Underground Space based on Wireless Sensor Network (비분산적의선 CO$_2$센서를 이용한 무선 센서 네트워크 기반의 지하 공기질 모니터링 시스템)

  • Kwon, Jong-Won;Kim, Jo-Chun;Kim, Gyu-Sik;Kim, Hie-Sik
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.46 no.4
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    • pp.28-38
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    • 2009
  • In this study, a remote air quality monitoring system for underground spaces was developed by using NDIR-based CO$_2$ sensor. And the remote monitoring system based on wireless sensor networks was installed practically on the subway station platform. More than 6.5 million citizens commutate everyday by the Seoul subway transportation that is the most typical public transportation. They concern about air quality with increasing interest on public health or many workers in subway stations or underground shopping centers. Recently, the Korean Ministry of Environment has operated the air quality monitoring system in some subway stations for testing phase. However, it showed many defects which are large-scale, high-cost and maintenance of precision sensors imported from abroad. Therefore this research includes the reliability test and a theoretical study about the inexpensive commercialized CO$_2$ sensor for reliable measurement of air quality which changes rapidly by the surrounding environments. And then we develop the wireless sensor nodes and the gateway applied for remote air quality monitoring. In addition, web server program was realized to manage air quality in the subway platform. This result will be valuable for a basic research for air quality management in underground spaces for future study.

New Synthesis of the Ternary Type Bi2WO6-GO-TiO2 Nanocomposites by the Hydrothermal Method for the Improvement of the Photo-catalytic Effect (개선된 광촉매 효과를 위한 수열법에 의한 삼원계 Bi2WO6-GO-TiO2 나노복합체의 쉬운 합성 방법)

  • Nguyen, Dinh Cung Tien;Cho, Kwang Youn;Oh, Won-Chun
    • Applied Chemistry for Engineering
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    • v.28 no.6
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    • pp.705-713
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    • 2017
  • A novel material, $Bi_2WO_6-GO-TiO_2$ composite, was successfully synthesized using a facile hydrothermal method. During the hydrothermal reaction, the loading of $Bi_2WO_6$ and $TiO_2$ nanoparticles onto graphene sheets was achieved. The obtained $Bi_2WO_{6-GO-TiO2}$ composite photo-catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis-DRS), and X-ray photoelectron spectroscopy (XPS). The $Bi_2WO_6$ nanoparticle showed an irregular dark-square block nanoplate shape, while $TiO_2$ nanoparticles covered the surface of the graphene sheets with a quantum dot size. The degradation of rhodamine B (RhB), methylene blue trihydrate (MB), and reactive black B (RBB) dyes in an aqueous solution with different initial amount of catalysts was observed by UV spectrophotometry after measuring the decrease in the concentration. As a result, the $Bi_2WO_6-GO-TiO_2$ composite showed good decolorization activity with MB solution under visible light. The $Bi_2WO_6-GO-TiO_2$ composite is expected to become a new potential material for decolorization activity. Photocatalytic reactions with different photocatalysts were explained by the Langmuir-Hinshelwood model and a band theory.

The Research Trend and Social Perceptions Related with the Tap Water in South Korea (수돗물 이용에 대한 국내 연구동향과 사회적 인식)

  • Kim, Ji Yoon;Do, Yuno;Joo, Gea-Jae;Kim, Eunhee;Park, Eun-Young;Lee, Sang-Hyup;Baek, Myeong Su
    • Korean Journal of Ecology and Environment
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    • v.49 no.3
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    • pp.208-214
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    • 2016
  • We analyzed research trend and public perception related with tap water to identify major factors affecting low consumption of tap water. 805 research articles were collected for text mining analysis and 1,000 on-line questionnaires were surveyed to find social variables influencing tap water intake. Based on the word network analysis, research topics were divided into 4 major categories, 1) drinking water quality, 2) water fluoridation, 3) residual chlorine, and 4) micro-organism management. Compared with these major research topics, scientific studies of drinking behavior, or social perception were rather limited. 22.4% of total respondents used tap water as drinking water source, and only 1% drank tap water without further treatments (i.e. boiling, filtering). Experience of quality control report (B=0.392, p=0.046) and level of policy trust (B=1.002, p<0.0001) were influential factors on tap water drinking behavior. Age (B=0.020, p=0.002) and gender (B= - 1.843, p<0.0001) also showed significant difference. To increase the frequency of drinking the tap water by social members, the more scientific information of tap water quality and the water policy management should be clearly shared with social members.

Field Comparison of Korean Diffusive Sampler and Charcoal Tube Methods for Determination of Organic Vapors (공기중 유기용제 농도 측정에 있어서 국산 확산포집기와 활성탄관의 비교연구)

  • Cho, Sook Ja;Paik, Nam Won
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.7 no.1
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    • pp.33-48
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    • 1997
  • Korean diffusive sampler (KDS) and charcoal tube (CT) were used for sampling n-hexane, trichloroethylene and toluene in air KDS was made by Department of Environmental Health, SNU-SPH in 1995. Surveys were conducted at ten industrial plants with organic solvents. The relationship between two sampling methods was examined by linear regression analysis, and concentrations by two sampling methods were compared using paired t-test. The results are as follows: 1. The geometric means by CT and KDS methods were 3.26ppm and 3.32ppm for n-hexane, 5.07ppm and 6.34ppm for toluene, and 7.18ppm and 7.90ppm for toluene, respectively. There was no significant difference between results by CT and KDS methods in three organic vapors (p>0.05). When linear regression analysis was performed, two sampling methods were highly related ; correlation coefficients were 0.98, 0.90 and 0.96 for n-hexane, toluene and trichloroethylene, respectively. 2. Airborne concentrations of n-hexane (n=21) were below 0.5 TLV level. The GM by two methods were almost same (3.09 ppm). And there was no significant difference between results by two methods (p>0.05). 3. Since toluene and trichloroethylene concentrations showed several levels, appropriate sampling rates were applied for each level. The GM of toluene concentrations by two methods at 0.5 TLV level were 3.75ppm and 5.48ppm. The KDS method overestimated the toluene concentrations at 0.5 TLV level (p<0.05). The GM values of toluene concentrations at 1 TLV level were 31.80ppm and 25.38ppm and at 2 TLV level were 64.13 ppm and 51.37 ppm. The KDS method underestimated concentration at both level (p<0.05). For trichloroethylene, the GM at 0.5 TLV level were 4.97 ppm and 7.11ppm. The KDS method overestimated the concentration of trichloroethylene (p<0.05). In conclusion, concentrations of three organic vapors measured by CT and KDS were not significantly different and results by two methods were highly related. But at contain concentrations, the levels by method were significantly different. Therefore, it is suggested that sampling rate of KDS should be studied simultaneously using CT method for organic vapors.

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Algorithms of the VLSI Layout Migration Software (반도체 자동 이식 알고리즘에 관한 연구)

  • Lee, Yun-Sik;Kim, Yong-Bae;Sin, Man-Cheol;Kim, Jun-Yeong
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.10
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    • pp.712-720
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    • 2001
  • Algorithms from the research of the layout migration were proposed in the paper. These are automatic recognition algorithm for the VLSI devices from it, graph based construction algorithm to maintain the constraints, dependencies, and design rule between the devices, and high speed compaction algorithm to reduce size of the VLSI area and reuse the design with compacted size for the new technology. Also, this paper describes that why proposed algorithms are essential for the era of the SoC (System on a Chip), design reuse, and IP DB, which are the big concerns in these days. In addition to introduce our algorithms, the benchmark showed that our performance is superior by 27 times faster than that of the commercial one, and has better efficiency by 3 times in disk usage.

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