• Fibers and Polymers
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• 제4권4호
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• pp.182-187
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• 2003

Low molecular weight copolymers of maleic anhydride and vinyl acetate were prepared to develop formaldehyde free cross-linking agents. Since lower molecular weight is favorable for efficient penetration of the finishing agent into the cotton fibers in the padding process, the concentration of the initiator, chain transfer agent and the monomer ratios were varied to obtain copolymers of low molecular weights. The prepared polymers were characterized by GPC, $^1{H-NMR}$, FTIR, DSC and TGA. Copolymers of molecular weights of 2 000 to 10 000 were obtained and it was found that the most efficient method of controlling the molecular weight was by varying the monomer ratios. Poly(maleic anhydride-co-vinyl acetate) did not dissolve in water, but the maleic anhydride residue hydrolyzed within a few minutes to form poly(maleic acid-co-vinyl acetate) and dissolved in water. However, the maleic acid units undergo dehydration to form anhydride groups on heating above ${160}^{\circ}C$ to some extent even in the absence of catalysts. The possibility of using the copolymers as durable press finishing agent for cotton fabric was investigated. Lower molecular weight poly(maleic anhydride-co-vinyl acetate) copolymers were more efficient in introducing crease resistance, which appears to be due to the more efficient penetration of the cross-linking agent into cotton fabrics. The wrinkle recovery angles of cotton fabrics treated with poly(maleic anhydride-co-vinyl acetate) copolymers were slightly lower than those treated with DMDHEU and were higher when higher curing temperatures or higher concentrations of copolymer were used, and when catalyst, $NaH_2$$PO_2$, was added. The strength retention of the poly(maleic anhydride-co-vinyl acetate) treated cotton fabrics was excellent.

• 한국안전학회지
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• 제28권2호
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• pp.42-48
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• 2013

The $CO_2$ suppression characteristics and flame structure of nitrogen-diluted methane counterflow non-premixed flame were studied experimentally and numerically. To mimic a situation where combustion product gases are entrained into a compartment fire, fuel stream was diluted with $N_2$. A gas-phase suppression agent, $CO_2$, was diluted in the air-stream to investigate the suppression characteristics by the agent. For numerical simulation, an one-dimensional OPPDIF code was used for comparison with experimental results. An optically-thin radiation model(OTM) was adopted to consider radiation effects on the suppression characteristics. It was confirmed experimentally and numerically that suppression limit decreased with increasing nitrogen mole fraction in the fuel stream. A turning point was found only when a radiation heat loss was considered and the extinguishing concentration for turning point was differently predicted compared to the experiment result. Critical extinguishing concentration when neglecting radiation heat loss was also differently predicted compared with the experimental result.

• Elastomers and Composites
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• 제52권3호
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• pp.187-193
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• 2017

In this study, the effect of the cure, mechanical properties, and oil resistance of NBR (acrylonitrile-butadiene rubber)/peroxide compounds were investigated for various co-agents. NBR compounds were characterized using a swelling test, a rheometer (MDR), and a compression set test. Mechanical properties were tested with original compounds, heated in air and exposed to the ASTM No.1, IRM 903 oil. NBR compounds were prepared using peroxide as the crosslinking agent. Trimethylolpropane trimethacrylate (TMPTMA), triallyl isocyanurate (TAIC), and 1,2-polybutadiene (HVPBD) were used as co-agents. The NBR compounds containing TMPTMA and HVPBD lowered the scorch time, while the addition of TAIC did not significantly change the scorch time. NBR compounds containing TMPTMA increased the crosslinking density, while the addition of TAIC and HVPBD lowered the crosslinking density. Moreover, the addition of TMPTMA improved the oil resistance of the NBR compound.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.252-252
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• 2002

Radiation synovectomy is an useful alternative treatment to rheumatoid arthritis and Re$\^$188/ is suggested as an ideal radiopharmaceutical agents because beta ray (2.1 MeV) emitted from Re$\^$188/ is appropriate for synovial cell ablation and gamma ray (155 KeV) is ideal for dosimetry. Its' ideal particle size (2-5 mm) was achieved by conjugation with tin-colloid, In this study, we investigated the toxicity, stability and biodistribution to evaluate the suitability of DA-7911 as a synovectomy agent. (omitted)

• Molecular & Cellular Toxicology
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• 제2권3호
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• pp.216-221
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• 2006

The cholinesterase-inhibiting organophosphorous (OP) compounds known as nerve agents are highly toxic. The principal toxic mechanism of OP compounds is the inhibition of acethylcholine esterase (AChE) by phosphorylation of its catalytic site. The reversible competitive inhibition of AChE may prevent the subsequent OP intoxication. In this study, three-dimensional quantitative structure-activity relationship (3D-QSAR) was performed to investigate the relationship between the 29 compounds with structural diversity and their bioactivities against AChE. In particular, predictive models were constructed using the comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). The results indicate reasonable model for CoMFA ($q^{2}=0.453,\;r^{2}=0.697$) and CoMSIA ($q^{2}=0.518,\;r^{2}=0.696$). The presence of steric and hydophobic group at naphtyl moiety of the model may lead to the design of improved competitive inhibitors for organophosphorous intoxication.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.869-872
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• 2004

A study on the solidification of sludge by reactive amendment agent was carried out in this paper. The reactive amendment agent used in this study is mainly composed of inorganic solidification agent and reactive adsorptive material. The reactive agent has a function of soil-cement-agent solidification and harmlessness of contaminant in waste. The reactive agent is environmentally friendly material to the surrounding environment. In this study, a series of tests and experiments including unconfined compressive strength, permeability, pH test, constituent analysis, leaching test were carried out to analyse engineering and environmental characteristics of solidified sludge treated reactive agent. The result of this research shows that the solidified sludge treated reactive agent is increased in strength and decreased in contaminant concentration.

• 대한전자공학회논문지TC
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• 제45권2호
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• pp.75-82
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• 2008

모바일 아이피는 무선 모바일 노드의 이동성에 따른 기존 아이피 주소 체계의 고유성 보장 문제를 해결하고자 제안되었다. 네트워크 레이어에서의 핸드오프는 모바일 광고 메시지를 수신하게 됨으로써 완료되는데, 메시지 광고 주기는 지연 시간과 밀접한 관련을 가지게 된다. 일반적으로 평균 500ms의 큰 지연시간을 발생시키게 되며 인터넷 전화나 멀티미디어 스트리밍 서비스와 같은 경우에 치명적인 문제로 작용할 수 있다. 기존의 기법에서는 최근의 모바일 광고 메시지를 저장하고 있는 캐싱 에이전트의 리플레잉 정책에 의하여 핸드오프 지연 시간을 감소시켰지만, 모바일 아이피 등록 과정 동안의 패킷 손실과 지연 시간 증가의 문제점을 가지고 있다. 본 논문에서는 위와 같은 문제를 해결하고자 캐싱 에이전트를 개선해 핸드오프 완료 전에 데이터 포워딩이 가능하도록 하였고, 또한 빠른 모바일 아이피 등록을 위해 CoA풀을 도입하여 핸드오프 지연 효과를 감소하는 기법을 제안하였다.

• 한국표면공학회지
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• 제19권4호
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• pp.140-148
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• 1986

Using sodium pyrophoshate as complexing agent, the characteristics and the magnetic properties of the films deposited from electroless cobalt plating bath have been studied. The result obtained are as following; 1. It was found that the optimum bath compositions consisted of 0.1M cobalt sulfate, 0.2M sodium hypophosphite as reducing agent, 0.4M sodium pyrophosphate as complexing agent and 0.5M ammonium sulfate as buffer agent, whereas good operating conditions were the bath of pH 10.5 adjusted with ammonia and 70$^{\circ}C$ of bath temperature, respectively. 2. The coercive force and the squareness of magnetic films were increased with deposition from the low temperature bath. 3. The phosphorous content in Co-P films deposited from these bath was relatively higher than that from Brenner bath. It was assumed to be due to codeposition of phosphorous from the pyrophosphate anion in the solution.

• 한국정보전자통신기술학회논문지
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• 제9권1호
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• pp.114-119
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• 2016

사물 인터넷과 멀티미디어 협동 작업 환경의 필요성을 기술하고, 그 기반 하에 CoAP 기반 스택에서의 오류 처리에 대해서 제안하였다. 본 논문은 CoAP 기반 게이트웨이 소프트웨어 스택에서의 오류 동기화에 대한 내용을 기술한다. 이 시스템은 CS_EDA, CS_ESA로 구성되어 있다. CS_EDA는 CoAP 기반 게이트웨이 소프트웨어 스택 환경에서 멀티미디어 원격 제어를 위하여 오류를 감지하는 에이전트이다. CS_ESA는 CoAP 기반 게이트웨이 소프트웨어 스택 환경에서 멀티미디어 원격 제어를 위하여 오류를 동기화하는 에이전트이다. CoAP 기반 게이트웨이 소프트웨어 스택에서의 멀티미디어 공동 작업 환경의 관점에서 오류 동기화는 협동 작업에 참가하는 참가자에게 상호작용적으로 오류를 동기화한다.

• 자원리싸이클링
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• 제24권4호
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• pp.32-37
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• 2015

이차전지 재료 등으로 사용되는 코발트는 콩고 민주공화국 등 일부 국가에 편중되어 있다. 국내 코발트의 안정적인 공급을 위한 해외 코발트광과 코발트 제련 기술의 확보는 필수적이다. 이에 본 실험에서는 콩고산 코발트 정광(Co ~ 8 wt%, Cu ~ 19 wt%, Fe ~ 3 wt%)을 용융환원시켜 얻어지는 합금상에 매트 내 황의 비율을 달리해 만든 2가지 조성의 매트를 제조했으며, 주된 원소는 19 ~ 21wt% Co, 39 ~ 41wt% Cu, 7 ~ 9wt% Fe이다. 매트 분쇄산물을 autoclave를 이용한 고온고압침출법으로 3가지의 영향(산화제 유무, 침출제인 황산 농도, 매트 제조 시 투입되는 황 함량)을 고려해 실험을 진행했다. 먼저 산화제(산소)의 존재는 Co 침출률 향상을 위해 필수적이며 낮은 농도의 황산을 사용하더라도 Co를 전량 침출시킬 수 있다. 둘째 산소 분위기에서 높은 황산농도는 Cu와 Fe의 침출률을 증가시켜 선택적인 Co 침출을 방해한다. 마지막으로 매트 내 황 함량은 Co의 침출률에는 영향이 크지 않음을 알 수 있었다.