• 한국토양비료학회지
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• 제13권2호
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• pp.65-70
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• 1980

우리나라 토양(土壤)의 입도분석(粒度分析)에 적합(適合)한 분산제(分散劑)를 선정(選定)하기 위하여 대표토양(代表土壤) 18점(点)에 대(對)한 표토(表土) 및 심토(深土)의 입도분석(粒度分析) 결과(結果)는 다음과 같다. 1. 토양입자(土壤粒子)가 작을수록 분산제별(分散劑別) 분산능력(分散能力)의 차이(差異)가 커지는 경향(傾向)으로 점토입자(粘土粒子)(<0.002mm)의 분석치(分析値)에 있어서 분산제(分散劑)에 따라 차이(差異)가 컸었다. 2. 분산율(分散率)은 Sodium Pyrophosphate가 가장 높고 다음으로 Sodium Hexametaphophate, Ammonium Hydroxide, Sodium Hydroxide, Sodium Oxalate 순(順)이었다. 3. Sodium Hexametaphosphate는 Volcanic Ash Soil만을 제외(除外)하고 우리나라 모두 토양(土壤)의 입도분석(粒度分析)에 있어서 분산제(分散劑)로써 사용(使用)할 수 있을 것으로 본다. 4. Volcanic Ash Soil의 분산율(分散率)은 분산제(分散劑)를 사용(使用)하지 않은 경우보다 오히려 감소(減少)되는 경향(傾向)이 있으므로 이의 분산방법(分散方法)의 선정(選定)에는 특별(特別)한 주의(注意)가 요망(要望)된다.

• 청정기술
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• 제10권2호
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• pp.73-87
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• 2004

세정은 거의 모든 산업분야에서 필요한 중간 공정으로 대부분의 산업분야에서 제품상의 이물질 제거를 위해 세정을 실시고 있으며 세정제로 CFC-113, 1,1,1-TCE (1,1,1-trichloroethane), MC (methylene chloride), TCE 등 과 같은 세정성과 재질호환성이 양호한 염소계세정제를 사용하여 왔다. 그러나 CFC-113, 1,1,1-TCE는 오존파괴 물질로 선진국에서는 이미 사용이 금지되어 있고 MC, TCE는 유해성 또는 발암물질로 판명되어 일부사업장에서 제한적으로 사용되고 있다. 그러므로 세정성이 좋고 환경/안전성이 우수한 대체세정제를 개발하여 사용 하거나 기존 개발된 세정제 중에서 우수한 세정제를 선정하여 사용하는 것이 필요한 실정이다. 대체세정제로는 수계/준수계세정제가 환경성과 경제적면에서 유망한 것으로 평가받고 있어 많은 사업장에서 사용될 전망이다. 이에 본 연구에서는 시판되고 있는 수계세정제 12종, 준수계세정제 6종을 선정하여 물성, 세정성, 헹굼성, 헹굼수 재활용성 등에 관한 비교 연구를 수행하였다. 그 결과 수계세정제는 습윤지수가 클수록 세정이 좋았지만 준수계세정제는 습윤지수와 연관이 없었다. 그리고 수계세정제와 준수계세정제에 의한 세정성과 헹굼성을 좋게 유지하기 위하여서는 일정농도 이하로 오염물의 농도 관리가 필요한 것으로 나타났다. 수계, 준수계세정제는 종류에 따라서 단순 정치분리법에 의하여 헹굼수 중의 오염물을 70% 이상 용이하게 제거할 수 있었다. 이것은 일부 세정제는 오염된 헹굼수 중에서 높은 유수분리 효율이 있어 헹굼수 중의 오염물을 제거하고 물을 재활용하는데 효율적임을 말해준다. 그리고 수계세정제가 함유된 오염물은 30 kDa 세공크기의 PAN 막을 사용한 한외여과방법에 쉽게 정화될수 있었다.

• 청정기술
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• 제14권3호
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• pp.184-192
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• 2008

불소계 화합물인 삼불화에탄올(2,2,2-trifluoroethanol, TFEA)와 수소화불화에테르(hydrofluoroether, HFE)는 성층권의 오존층을 파괴하지 않으며, 수소화불화탄소(hydrofluorocarbon, HFC) 및 수소화염화불화 탄소(hydrochlorofluorocarbon, HCFC)계 세정제에 비하여 지구온난화 영향력도 낮다. 특히, 인화점이 없는 HFE계 세정제는 낮은 인화점을 갖는 탄화수소계 세정제보다 취급에 안전하고 침투력이 우수하여 차세대 염화불화탄소(chlorofluorocarbon, CFC) 대체세정제로 주목받고 있다. 본 연구에서는 불소계 세정제인 TFEL HFE-7100, HFE-7200, HFE-476mec, HFE-449mec-f, AE-3000, AE-3100E와 실리콘계 세정제인 트리플 루로에톡시트리메틸실란(trifluoroetoxytrimethylsilane, TFES)와 헥사메틸디실라잔 (hexamethyldisilazane, HMDS)의 물성과 세정력을 오존파괴 물질인 CFC-113, 삼염화에탄(1,1,1-trichloroethane)와 유해물질인 이염화탄소(methylene chloride, MC) 등의 염소계 세정제, 그리고 현재 대체세정제로 많이 사용하고 있는 이소프로필알코올(isopropyl alcohol, IPA) 등과 비교 평가하였다. 그 결과 TFEA와 HFEs는 일반적으로 발생하는 다양한 오염물질들에 대하여 염소계 세정제에 비하여 낮은 세정능력을 보여주었지만, 불소를 함유한 불소계 오염물의 제거에는 우수한 세정력을 보였다. 그리고 실리콘계 세정제인 TFES와 HMDS도 실리콘계 오염물에 대한 세정력이 우수함을 보여주었다.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.508-526
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• 1995

This experiment was performed to study mechanisms of desensitization by chemical desensitizing agents in hypersensitive dentin and compare effects of these agents by measuring the activity of intradental nerves and observing their occluding aspects on dentinal tubules with SEM over time after application of chemical desensitizing agents to the exposed dentinal surfaces. Canines of adult cats weighing 2-3 kg were cross-sectioned at 1.5 mm from incisal apex, and the smear layer of the exposed dentinal susface was removed by 32 % $H_3PO_4$ for 15 sec. Chemical desensitizing agents such as 10% $SrCl_2$, 5% $KNO_3$ and 30% $K_2C_2O_4$, were applied to the exposed dentin surfaces for 2 minutes. Intradental nerve activity was measured immediately after application of the agents, at 15 minutes and at 30 minutes by stimulating with 4M NaCl. To compare occluding ability of desensitizing agents on dentinal tubules in vivo and in vitro, the structures of the exposed dentinal surfaces of nonvital and vital teeth were morphologically observed by SEM. The results obtained were as follows : 1. Intradental nerve activity was decreased immediately after the application of 10 % $SrCl_2$, 5% $KNO_3$ and 30% $K_2C_2O_4$. (p<0.01), among which 30% $K_2C_2O_4$. showed the highest desensitizing effect(p<0.01). 2. The immediately decreased intradental nerve activity after application of 10 % $SrCl_2$ and 5% $KNO_3$ was increased over time. 10% $SrCl_2$ and 5% $KNO_3$ showed no desensitizing effect respectively at 30 minutes and at 15 minutes after application. 3. The immediately decreased intradental nerve activity after application of 30 % $K_2C_2O_4$ was persistently continued during the period of observation (p<0.01). 4. Precipitates of $SrCl_2$ and $KNO_3$ were not noted on the exposed dentinal surfaces and within dentinal tubules by SEM examination. On the other hand, 30 % $K_2C_2O_4$ produced precipitates on the exposed dentinal surfaces and openings of dentinal tubules without any formed preciptates within dentinal tubules. 5. Ten percent $SrCl_2$, 5 % $KNO_3$ and 30 % $K_2C_2O_4$ showed no differences in their occluding aspects on dentinal tubules either in vivo or in vitro studies and either immediately following application or at 30 minutes. These results suggest that the desensitizing effect of $SrCl_2$ and $KNO_3$ is resulted from their reducing effect on the intradental nerve activity rather than from their precipitates' occluding the dentinal tubules. However, desensitizing effect of 30 % $K_2C_2O_4$, is probably resulted from its precipitates' occluding the openings of the dentinal tubules as well as from it's reducing effect on the intradental nerve actibity.

• 한국유기농업학회지
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• 제19권spc호
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• pp.263-266
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• 2011

Crop protection strategies in organic horticulture aim to prevent insect pest and plant disease problems through utilization of non-chemical based control means. In order to develop a model for management of plant diseases and insects in organic cucumber cultivation, we compared efficacies between chemical pesticide spraying system and biological control means in semi-forcing and retarding cucumber cultivation during 2005 and 2006. Conventional chemical spray program using various chemical pesticides was applied 5 - 10 days intervals, while two different non-chemical pesticide application programs using two formulated biopesticides Topseed$^{TM}$ and Q-fect$^{TM}$, Suncho$^{TM}$, and Sangsungje$^{TM}$ (biocontrol agents 1) and using egg-yolk and cooking oil(EYCO), Bordeaux mixture, Suncho$^{TM}$, and Sangsungje$^{TM}$ (biocontrol agents 2) were applied 5 - 7 days intervals during entire cucumber cultivation period. Efficacy of both biocontrol agents programs was effective to comparable to conventional chemical pesitice spray program to control plant diseases such as powdery mildew and downy mildew as well as insect pests such as aphids and thrips which are known as major threats in cucumber organic cultivation. In this study, we established and evaluated an effective and economic crop protection strategy using various biological resources can be used to control plant diseases and pests simultaneously in organic cucumber cultivation field.

• 한국염색가공학회지
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• 제32권2호
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• pp.73-79
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• 2020

Pursuing the fabric materials for military chemical warfare protective clothing with the improved detoxification properties, this study investigated the simple and effective cotton treatment method using pad-dry-cure process and 3-aminopropyltrimethox ysilane(APTMS) solution for surface amination. Detoxification properties of the untreated and treated cotton fabrics were evaluated via decontamination of chemical warfare agent simulant, DFP(diisopropylfluorophosphate). The surface aminated cotton fabric increased the rate of the hydrolysis of DFP by the factor of 3 and the decontamination ratio reached 88.2% after 24h. Therefore, the surface amination of the cotton fabric with APTMS can be an effective pathway to prepare the material for protective clothing against chemical warfare agents.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.354-354
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• 2006

Alginic acid-silica hydrogel films was prepared for testing as protective coating materials for PTFE OD membranes. Unprotected hydrophobic membranes are subject to wet-out when contacted by surface-active agents. Films were characterised using SEM, XRD, DSC, mechanical strength measurements, and water-swelling measurements. In OD trials using coated membranes, no wet-out occurred over the 15 h duration of three consecutive 5 h OD trials using orange oil-water mixtures. In the case of detergent solutions, the coating afforded protection to the membrane for 4-5 h. In a separate trial, no wet-out occurred when the coated side of the membrane was placed in contact with 1.2 wt % orange oil for 72 hours.

• Membrane and Water Treatment
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• 제8권5호
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• pp.463-481
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• 2017

Bacteria have been considered as a major foulant that initiates the formation of biofilm on the polymeric membrane surface. Some polymeric membranes are naturally antibacterial and have low fouling properties, however, numerous efforts have been devoted to improve their antibacterial performance. These modifications are mostly carried out through blending the membrane with an antibacterial agent or introducing the antibacterial agent on the membrane surface by chemical grafting. Currently, a significant number of researches have reported nanocomposite membrane as a new approach to fabricate an excellent antibacterial membrane. The antibacterial nanoparticles are dispersed homogenously in membrane structure by blending method or coating onto the membrane surface. Aim of the modifications is to prevent the initial attachment of bacteria to membrane surface and kill bacteria when attached on the membrane surface. In this paper, several studies on antibacterial modified membranes, particularly for water treatment, will be reviewed comprehensively. Special attention will be given on polymeric membrane modifications by introducing antibacterial agents through different methods, such as blending, grafting, and coating.

• 한국응용과학기술학회지
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• 제17권4호
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• pp.267-272
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• 2000

Dual-actions are the most recently used delivery system in drug study. Dual-action agents are unique chemical entities comprised of two different type of antibacterial compounds covalently linked together in a single molecule in such a way that both components are able to exert their bactericidal properties. Crosslinked sulfadiazine-sulfanilamide such as antibiotics is synthesized by synthetic handle with glutaraldehyde. As a result, New synthetic antibacterial agent exhibited the broad antibacterial activities against gram(+) and gram(-) of 4 strains and a long durability supposing that the stomach and blood.

• Carbon letters
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• 제16권1호
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• pp.34-40
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• 2015

In this study, in order to improve the thermal and electrical properties of epoxy/graphene nanoplatelets (GNPs), surface modifications of GNPs are conducted using silane coupling agents. Three silane coupling agents, i.e. 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane (ETMOS), 3-glycidoxypropyltriethoxysilane (GPTS), and 3-glycidoxypropyltrimethoxysilane (GPTMS), were used. Among theses, GPTMS exhibits the best modification performance for fabricating GNP-incorporated epoxy composites. The effect of the silanization is evaluated using transmission electron microscopy (TEM), scanning electron microscopy, thermogravimetric analysis, and energy dispersive X-ray spectroscopy. The electrical and thermal conductivities are characterized. The epoxy/silanized GNPs exhibits higher thermal and electrical properties than the epoxy/raw GNPs due to the improved dispersion state of the GNPs in the epoxy matrix. The TEM microphotographs and Turbiscan data demonstrate that the silane molecules grafted onto the GNP surface improve the GNP dispersion in the epoxy.