• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.505-514
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• 2009

Aqueous potassium salt of serine was proposed as an alternative $CO_2$ absorbent to monoethanolamine (MEA) and its $CO_2$ absorption characteristics were studied. The experiment has been conducted using screening test equipment with NDIR type gas analyzer and vapor-liquid equilibrium apparatus. $CO_2$ absorption/desorption rate and net amount of $CO_2$ absorbed in cyclic process are the criteria to assess the $CO_2$ absorption characteristics in this study. Effective $CO_2$ loading of potassium salt of serine and MEA are 0.425 and 0.230 respectively. Cyclic capacities are 0.354 and 0.298 for potassium salt of serine and MEA. The absorption rate of the potassium serinate decreased sharply at $CO_2$ loading is 0.1 and were maintained approximately at half of MEA. To enhance the absorption rate of aqueous potassium salt of serine, small quantities of rate promoters, namely piperazine and tetraethylenepentamine were blended, so that rich $CO_2$ loading were increased by 13.7% and 18.7% respectively. The rich $CO_2$ loading of potassium salt of serine was 29.2% and 35.0% higher than those of aqueous sodium and lithium salt of serine, respectively. The absorption rate of potassium salt of valine and isoleucine which have similar molecular structures to serine were lower than that of serine because of the presence of bulky side group. Precipitation phenomena during $CO_2$ absorption were discussed by the aid of literatures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.3
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• pp.195-202
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• 2006

Deterioration of sewer concrete is representative that biochemical corrosion according to the $H_2S$ has growth by inhabit sulfur-oxidzing bacteria because of special environment in sewer. But in case of domestic, fundamentally, sulfur-oxidzing bacteria could moderate development of repair material method is need because of corrosion prevent method is inconsideration with carry out to improve project. In this paper, after development of spread type antibiotic with antibio-metal, antibacterial performance about sulfur-oxidzing bacteria of antibiotic and tested to estimate fundamental properties of bonding strength, abrasion contents, contents of water absorption, contents of air permeability, carbonation depth, chloride ion penetration depth and chemical resistance of spread with antibiotic restorative mortar.

• Journal of the Korean Ceramic Society
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• v.38 no.2
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• pp.107-111
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• 2001

Sr$_{(1-x)}$Ca$_{x}$TiO$_3$: Pr$^{3+}$ , Ga$^{3+}$ (0$\leq$x$\leq$1) 형광체의 여기 및 발광 스펙트럼과 분광 반사율을 조사하여 발광 메커니즘을 규명하고자 하였다. 발광 스펙트럼에서는 611~614nm 사이에서 peak을 가지는 하나의 적색 발광 밴드가 관찰되었으며, 조성에 따라 발광밴드의 모양이 달랐다. 이는 조성에 따른 모체의 결정 구조 변화 때문으로 생각된다. 여기 스펙트럼 끝단과 분광 반사율 스펙트럼의 흡수단은 서로 일치하였으며, 이 결과로부터 모체에 흡수된 에너지가 Pr$^{3+}$ 에 전달되어 적색광을 방출하는 것이 주된 메커니즘으로 생각된다. 한편 120$0^{\circ}C$에서 4시간동안 열처리하여 합성한 Sr$_{0.4}$Ca$_{0.6}$TiO$_3$:(0.1 mol%)Pr$^{3+}$ , (0.2 mol%)Ga$^{3+}$ 는 우수한 색순도와 휘도를 나타내었다.다.

• Journal of the Korean Chemical Society
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• v.37 no.7
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• pp.662-671
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• 1993

New Ni(II) and Pd(II) complexes of isonitrosomethylacetoacetate imine derivatives, Ni(IMAA-NH)(IMAA-NH'), Ni(IMAA-NH)(IMAA-NR), $Pd(IMAA-NH)_2\;and Pd(IMAA-NR)_2(R=CH_3,\;C_2H_5,\;n-C_3H_7,\;n-C_4H_9,\;or\;CH_2C_6H_5)$, where H-IMAA-NH and H-IMAA-NR represent isonitrosomethylacetoacetate imine and N-alkylisonitrosomethylacetoacetate imine derivative, respectively, have been prepared and the structures of the complexes have been studied by elemental analyses, electronic, infrared, and $^1H-\;and\;^{13}C-NMR$ spectroscopies.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.57.2-57.2
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• 2009

퍼클로레이트 이온($ClO_4^-$)는 자연적으로 혹은 인공적으로 만들어지며 퍼클로릭산이나 암모늄 퍼클로레이트나, 포타슘 퍼클로레이트 혹은 소듐퍼클로레이트 염의 형태로 존재하며, 물에 아주 잘 녹고, 끓여도 제거되지 않으며, 활성 탄소와 같은 광물에도 흡착 되지 않는 성질로 인해, 기존 물리적인 정수 방법으로는 제거하기 어렵다. 또한 우리 몸에 흡수되면, 요오드가 갑상선에 흡수되는 작용을 방해하여 갑상선 기능장애를 초래한다. 이러한 퍼클로레이트 이온의 제거방법으로는 이온교환법이나 생물학적 방법 등이 개발되어져 있으나, 제거 시스템에 이동 및 안전한 농도까지 제거 등의 문제점으로 인한 퍼클로레이트 이온을 환원시키는 촉매 환원 반응에 의한 퍼클로레이트 이온 제거 기술 개발이 필요하다. 이런 촉매 환원에 필요한 수소 환원제를 발생시키기 위해서, 본 연구에서는 Carbon felt 위에 DC magnetron sputtering에 의한 thin film $TiO_2$과 regine을 이용한 powder $TiO_2$ 시편을 제작하였다. 이렇게 제작 된 $TiO_2$/Carbon felt의 미세구조 및 특성은 XRD, SEM, UV-vis-NIR 등을 통하여 분석하였다. UV 조사에 의해 $TiO_2$/Carbon felt 시편의 산소와 수소 발생과 DC bias의 걸어주었을 때 산소와 수소 발생 차이 등을 비교하였고, 이에 따른 퍼클로 레이트 이온의 분해 영향을 알아보았다.

• Polymer(Korea)
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• v.37 no.4
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• pp.478-485
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• 2013

In this study, hydrogels with fast swelling and high absorbent properties were prepared using biopolymers approved as a food additive and their swelling properties were characterized. To improve the swelling properties of conventional hydrogels, we formed gas bubbles using a foaming agent in the process of preparing hydrogels and characterized in terms of equilibrium swelling ratio, swelling kinetics and cytotoxicity. In particular, alginate hydrogels observed by a digital microscope have an open-pore channels structure with the sizes of hundreds micrometers. Also, the cell viability of all hydrogels were found to be much higher than that of poly(acrylic acid).

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.61-61
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• 2011

비스코스 레이온(Viscose Rayon)은 목재 펄프를 원료로 한 재생섬유로서 은은한 광택과 발색성, 흡습성 등의 기능 뿐만 아니라, 천연섬유에 찾을 수 없는 Numeri감(Smoothness), Drape(처짐)성, 반발탄성을 가지고 있는 지극히 친환경적이며 자연순환형 소재로 인식, 지구온난화에 따른 CoolBiz Look 패션소재인 레이온 소재에 관심이 증대되고 있다. 한편, 레이온 소재는 수분흡수 시 강도저하, 수축과 구김, 염색 불균염 등의 문제점과 섬유공정상 생활취급상에 많은 애로를 가지고 있으며, 구성고분자가 수소결합에 의해 강고하여 "신축문제", 수분흡수시 팽윤(Swelling)에 의한 형태불안, 즉 "수축문제"가 개선해야 할 고질적 문제로 남아 있다. 또한, 습식방사에 따른 분자구조적 불안정성으로 건 습열처리시 형태불안정(치수변화율이 큼)으로 제직(준비) 및 후공정상 여러 가지 Trouble 유발과 완제품 세탁시 수축발생으로 종종 Dry Creanning해야 하는 문제점들이 내재되어 있다. 따라서 본 연구에서는 레이온 소재의 형태안정화 제품을 개발하기 위하여 복합사가공 및 염색가공 기술을 개발하고자 하며, 신축 및 복합기술에 의한 Rayon DTY, T/R 신축 및 복합기술에 의한 Rayon DTY, T/R 복합가공사를 개발, 제편직 요소기술과 최적의 전처리 조건, 다양한 염료의 종류, 염색온도 조건 등에 관한 연구를 진행하였다.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.1
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• pp.1-13
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• 2012

Short implants are used in parts which have anatomical structures like maxillary sinus, inferior alveolar nerve and limited alveolar height due to severe alveolar bone resorption. In these case, there are no need of additional bone augmentation so there are advantages like reduced entire treatment time, reduced patient's discomfort and protection of important anatomical structures. The aim of this study is, in implants whose length is less than 10mm, to analyze the impact of implant length, diameter, location of implant placement, presence of bone graft, presence of prosthesis splinting on survival rates and marginal bone resorption. The samples used in this study were 227 implants, less than 10mm, placed in 137 patients in Wonkwang university dental hospital implant center. From dental charts the information about implant length, diameter, location of implant placement, presence of bone graft, presence of prosthesis splinting were obtained. Emago advanced v5.6(Oral diagnostic systems, Amsterdam, The Netherlands)program was used to measure the amount of marginal bone resorption. Out of total 227 implants, resulting in 96.5 % of survival rate. There was a tendency toward higher failure rates for the maxilla and bone graft site. No significant difference in marginal bone resorption was found associated with length of implants(p>0.05) and neither with the diameter of implants. Among the risk factors examined, more failure rates of short implants can be attributed to poor bone quality in the maxilla and presence of bone graft. At implants under 10mm, length, diameter, location of implant placement, bone graft and splinting of prosthesis didn't affect marginal bone loss.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.207-212
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• 2023

Near-infrared (NIR) absorbing dyes have been applied to various applications such as optical filters, biotechnology, energy storage and conversion, coating additive, and traditionally information-storage materials. Because image sensors used in cellphones and digital cameras have sensitivity in the NIR region, the NIR cut-off filter is essential to achieving more clear images. As energy storage and conversion have been important, diverse NIR absorbing materials have been developed to extend the absorption region to the NIR region, and NIR absorbing materials-based research has proceeded to improve device performances. Adding NIR-absorbing dye with a photo-thermal effect to a self-healable coating system has been attractive for future mobility technology, and more effective self-healing properties have been reported. In this report, the chemical structures of representative NIR-absorbing dyes and state of the art research based on NIR-absorbing dyes are introduced.

• Journal of the Korea Concrete Institute
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• v.28 no.3
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• pp.317-328
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• 2016

This research intends to understand the impact of super-absorbent polymer (SAP) as an internal curing agent in Ultra-High Performance Concrete (UHPC). Two different types of SAPs of acrylic acid (SAP_AA) and acrylic acid-co-acrylamide (SAP_AM) were examined with UHPC formulation. Isothermal calorimetry and x-ray diffraction experiments revealed the impact of polymers with the different chemical bonds on cement hydration. To test its feasibility as a shrinkage reducing admixture for UHPC, a series of experiments including flowability, compressive strength, rapid chloride permeability and autogenous shrinkage profile was performed. While both SAPs showed a reduction in autogenous shrinkage, it has been concluded that the SAP size and chemical form significantly affect the performance as an internal curing agent in UHPC by controlling cement hydration and porosity modification. Between the tested SAPs, SAP_AM which absorbs more water in UHPC than SAP_AA, shows better mechanical and durability performance.