• 농약과학회지
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• 제2권1호
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• pp.1-11
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• 1998

The generally accepted idea for carbohydrate translocation in plants is an osmotic pressure flow hypothesis. According to the hypothesis, a high concentration of carbohydrate in the phloem of carbohydrate synthesis regions (source) causes a water influx into the phloem. The generated osmotic potential in the phloem is responsible for long distance carbohydrate transport through the positive hydrostatic pressure. In regions of carbohydrate utilization and storage (sink), translocated carbohydrates are continuously metabolized and compartmentalized, generating a concentration gradient between source and sinks. In this system, carbohydrates load into the phloem (phloem loading) and unload out of the phloem (phloem unloading). Phloem-mobile herbicides that are applied to plants are also translocated from the source to sinks. However, some experimental results reveal that the patterns of phloem translocation between carbohydrates and herbicides are different. The differences are due, in part, to the physico-chemical properties of herbicides and to the absence/presence of specific carrier(s) in the phloem.

• 한국안전학회지
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• 제21권1호
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• pp.86-91
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• 2006

Oil spills caused by the accidents have been occurred from house and factory waste, grounded tanker, the rupture of storage tank and oil pipelines, the deterioration of various industrial facilities, etc. Many oil spills result in contamination of shorelines and workplace. Fire and explosion may happen from these spills. There are several technologies used for clean-up application, which include use of oil dispersing agents, absorbents, solidifiers, booms and skimmers by physical, chemical, and biological methods. Methods for oil spill clean-up operation are classified into the absorption type, gel type and self-swelling type. Porous materials with oil absorptive properties are classified into micropore, mesopore, and macropore depending on their pore sizes. Recently, new porous materials with smaller size have been developed, but the selective oil absorption in water-in-oil interface demonstrates the macro pore size. In this study oil absorption effects were evaluated using the organic porous materials with a complex function of gel type and swelling type. Samples were subjected to analysis by FT-IR spectroscopy and were characterized in terms of gel formation and morphologies. Oil sorption capacity, pressure retention force and gel strength were also measured. From these results, the physicochemical reactivity before and after gelation was verified and the industrial applications of clean-up operation were suggested.

• 한국재료학회지
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• 제16권7호
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• pp.422-429
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• 2006

Studies were performed on preparation of organic-inorganic hybrid silica dye in a dispersing ink system. The silica was subjected to surface modification using 3-aminopropyltrimethoxysilane (APTMS) in order to promote the chemical reactivity of the raw silica. On the surfaces of the aminosilane-functionalised silica, red vinylsulfone-containing azo dye was adsorbed. The dye was found to have chemically reacted with the aminosilane-grafted silica surface, which was proven by FT-IR spectra. Studies on morphology and microstructure were performed employing scanning electron microscopy. The SEM micrographs and particle size distributions showed that a homogeneous pigment can be obtained employing silica as a core. Particle size distribution was also examined using the technique of dynamic light scattering. The ensuing pigment was subjected to various physicochemical evaluation such as inkjet property, storage stability, color change as inkjet ink using printer, spectrophotometric, microscopic techniques. Studies on hybrid dyes from the silica surface demonstrated that, in general, stable pigments for inkjet dispersion ink were obtained.

• 한국실내디자인학회논문집
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• 제15권2호
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• pp.37-47
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• 2006

The purpose of this study was to provide basic data for better design of Pharmacy after introducing the new system of separation of dispensing from prescribing medicine. To analyze characteristics of interior design in pharmacy and to measure worker satisfaction, a survey was conducted with 255 workers who serve at any Pharmacies located in Busan, Korea. For data analysis, descriptive statistics, t-test, One-way ANOV A were performed with the SPSS Win program(Ver. 10.0). The major findings were as follows: 1) As a result of analyzing the role and functions of the pharmacist is to be classified into many items such as entrance, a waiting room, a dispensary, a medication & consultation area, a drug storage and a worker's room. 2) Natural substances should be used more widely instead of using chemical substances for the pharmacy interior design as finishing materials 3) Pharmacy worker's satisfaction with dispensary is specially low among the total satisfaction which is :slightly higher than the average. 4) The degree of satisfaction between pharmacy workers from different groups varied depending on work hours, and especially long time(over 10hrs) workers showed dissatisfaction. Pharmacy managers need to consider the option of expanding convenience facilities. 5) According to the satisfaction analysis for each pharmacy conditions, the group who worked in 30-pyeong spaces were most satisfied. Since the 30-pyeong space is most standardized space research should be conducted.

• 청정기술
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• 제26권4호
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• pp.279-285
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• 2020

Laboratories and industrial processes typically involve the use of flammable substances. An important property used to estimate fire and explosion risk for a flammable liquid is the flash point. In this study, flash point data at 101.3 kPa were determined using a SETA closed cup flash point tester on the following solvent mixtures: {2,2,4-trimethylpentane + methylcyclohexane}, {2,2,4-trimethylpentane + ethylbenzene}, and {2,2,4-trimethylpentane + p-xylene}. The purpose of this work is to obtain flash point data for binary mixtures of 2,2,4-trimethylpentane with three hydrocarbons (methylcyclohexane, ethylbenzene, and p-xylene), which are representative compounds of the main aromatic hydrocarbon fractions of petroleum. The measured flash points are compared with the predicted values calculated using the GE models' activity coefficient patterns: the Wilson, the Non-Random Two-Liquid (NRTL), and the UNIversal QUAsiChemical (UNIQUAC) models. The non-ideality of the mixture is also considered. The average absolute deviation between the predicted and measured lower flash point s is less than 1.99 K, except when Raoult's law is calculated. In addition, the minimum flash point behavior is not observed in any of the three binary systems. This work's predicted results can be applied to design safe petrochemical processes, such as identifying safe storage conditions for non-ideal solutions containing volatile components.

• 한국수산과학회지
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• 제55권5호
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• pp.670-680
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• 2022

Owing to the lack of a cold-chain distribution system, most seafood is generally distributed under room temperature conditions. However the degradation of freshness during the distribution process can lead to disputes between sellers and consumers. The most widely used method for low-temperature distribution for seafood includes packaging it with styrofoam boxes and cold packs. In this study, vacuum-packed frozen fillets of four fish species of [white meat (Paralichthys olivaceus and Sebastes schlegelii) and red meat (Scomber japonicus and Scomberomorus niphonius)] were placed in styrofoam boxes with cold packs. Thereafter, changes in chemical (including pH, volatile basic nitrogen, and trimethylamine), physical (odor intensity, hardness, and chewiness), and microbial (viable cell count) characteristics of the fillets were measured during storage at 25℃. To identify the suitable method of determining freshness during the room-temperature distribution, several factors were considered, which included significant difference verification, correlation coefficients, and economic efficiency (experimental cost and time). Volatile basic nitrogen, pH, odor intensity, and viable cell count are the most rapid and accurate freshness indicators for determining freshness of frozen fish fillets during.

• 한국가스학회지
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• 제17권6호
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• pp.73-82
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• 2013

현대사회의 산업발전과 새로운 기술개발로 다양한 화학제품이 생산되어 인류생활을 윤택하게 하였지만 일부 화학물질은 국민의 안전과 환경에 많은 위험을 주고 있으며, 이들의 운송, 저장, 취급 등의 안전관리 문제가 대두되고 있는 실정이다. 특히, 도로운송 위험물은 사고빈도가 높아서 체계적인 안전관리시스템이 필요하다. 따라서 본 연구에서는 국내 운송위험물의 현황, 관련법 및 문제점을 파악하고, 국제운송위험물규칙(UN-RTDG)과 비교 검토하여 선진화된 안전관리 정책제언과 도로운송 위험물 분류표준화 방안 및 통일된 운송위험물 표시를 제시하였다. 이와 같은 선진화된 위험물질 안전관리에 의해 사고예방 및 대응을 최적화하여 인류의 건강과 환경보호에 기여할 것이다.

• 한국식품과학회지
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• 제5권1호
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• pp.36-41
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• 1973

라면제조(製造)과정중 frying 유지(油脂)(주원료 유지(油脂)는 beef tallow, 유지회전율(油脂回轉率) 9%/hr, 가열온도(加熱溫度) $140{\pm}10^{\circ}C)$의 안정성(安定性)을 작업시간 경과에 따라 공장규모(工場規模)로 검토한 바, 다음과 같은 결과(結果)를 얻었다. 1) 작업시간 경과에 따른 frying 유지(油脂)의 carbonyl 가(價) 및 과산화물가(過酸化物價)의 변화(變化)는 비교적 적었고, 산가(酸價) 및 착색성(着色性)은 다소(多少) 증가하는 경향이었다. 2) Silicic acid column 을 이용한 liquid partition chromatography 법(法)에 의하여 중합물(重合物)을 검토한 바, 대부분(大部分)이 monomer 이었으나 polar fraction에서 미량(微量)이나마 frying 시간의 경과에 따른 dimer 의 증가를 주목(注目) 할 수 있었다. 또한 지방산조성(脂肪酸組成)에서는 현저한 변화는 없었으나 linolenic, linoleic 가 증가한 반면에 stearic, palmitic acid가 감소하였으나 적은 량(量)이었다. 3) 시간경과에 따른 각 시료(試料)의 시험저장결과, 신선유지(新鮮油脂)는 저장 초기(初期)에 있어서 다른 사용유(使用油)에 비(比)하여 중량증가(重量增加) 및 carbonyl 가(價) 공(共)히 안정(安定)한 경향이었고, 저장중 사용유간(使用油間)에 있어서 안정성(安定性)의 차이는 적었다.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2771-2775
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• 2011

Poly-ethylenedioxypyrrole (PEDOP) coated thiolated multiwall carbon nanotubes palladium nanoparticles (MWCNTs-Pd) modified glassy carbon electrode (GCE) [PEDOP/MWCNTs-Pd/GCE] for the determination of hydroquinone (HQ) and it’s isomer catechol (CA) were synthesized and compared with bare GCE and thiolated multiwall carbon nanotubes (MWCNTs-SH/GCE). The modification could be made by simple processes on a GCE with MWCNTs-Pd covered by PEDOP in a 0.05 M tetrabutylammonium perchlorate (TBAP)/MeCN solution system. A well-defined peak potential evaluation of the oxidation of hydroquinone to quinone at 0.05 V (vs. Ag/AgCl), and electrochemical reduction back to hydroquinone were found by cyclic voltammetry (CV) in phosphate buffered saline (PBS) at pH 7.4. Peak current values increased linearly with increasing hydroquinone contents. The peak separation between the anodic and cathodic peaks at the PEDOP/MWCNTs-Pd/GCE was ${\Delta}Ep$ = 40 mV for HQ and ${\Delta}Ep$ = 70 mV for CA, resulting in a higher electron transfer rate. Moreover, good reproducibility, excellent storage stability, a wide linear range (0.1 ${\mu}M$ - 5 mM for HQ and 0.01 ${\mu}M$ - 6 mM for CA), and low detection limits ($2.9{\times}10^{-8}$ M for HQ and $2.6{\times}10^{-8}$ M for CA; S/N = 3) were determined using differential pulse voltammetry (DPV) and amperometric responses; this makes it a promising candidate as a sensor for determination of HQ and CA.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.683-686
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• 2004

In recent years, the supercapacitor and hybrid capacitor have related with substitutional energy source focused of many scientists because of their usage in power sources for electric vehicles, computers and other electric devices. The storage energy of electrical charge is based on electrostatic interactions in the electric double layer at the electrode/electrolyte interface, resulting in high rate capability and long cycle performance compared with batteries based on Faradaic electrode reactions. So we have been considered to carbon nanofibers as the ideal material for supercapacitors due to their high utilization of specific surface area, good conductivity, chemical stability and other advantages. In this work, we aimed to find out that the capacitance have increased because of electrochemical capacitance to provide by carbon nanofibers. Also carbon nanofibers based on chemical method and water treatment have been resulted larger capacitances and also exhibit better electrochemical behaviors about 15% than before of nontreated state. And also optical observations with treated and nontrteated carbon nanofibers discussed by the TEM, SEM, EDX, BET works and specific surface area analyzer. Their results also focused on the surface area of electrode and electrical capacitance was also improved by the effect of surface treatments.