• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.3
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• pp.289-297
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• 2017

Local and general factors have been attributed to root resorption occurred by injuries such as trauma and dental caries that affect periodontal ligament or dental pulp tissue. Pathologic root resorption is different from physiologic root resorption in terms of resorption pattern such as micromorphology of resorption fossae and types of observed cells. Microscopic morphologies and histologic features of physiologic and pathologic root resorption surface of maxillary primary central incisors resulting from trauma and periapical inflammation were observed by scanning electron microscope and light microscope. The morphology of physiologic resorption lacunae was small and oval or circular shape with regularities. The morphology of pathologic resorption lacunae was large and polygonal shape with irregularities compared with the physiologic resorption lacunae. Multinucleated giant cells and mononuclear cells were closely attached to the physiologic and pathologic resorption lacunae, whereas several kinds of mesenchymal cells with numerous inflammatory cells were found in the areas adjacent to the pathologic resorption surface. Compensating cementum formation took place along some of the areas of physiologic and pathologic resorption area resulting from trauma, but could not be observed on pathologic resorption area resulting from periapical inflammation.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.492-497
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• 2008

The solubility of carbon dioxide in ionic liquids and amine solvents has been investigated in gas-liquid absorption equilibrium reactor. Absorption capacity and kinetics of $CO_2$ with $CO_2$ pressure and absorption time in 9 different ionic liquids and 2 kinds of amine solvents were evaluated. In order to understand the effect of ionic type, we changed the cation or anion of ionic liquids. $CO_2$ absorption capacity and absorption rate of amine solvents were higher than those of ionic liquids. $CO_2$ absorption capacity of [emim][$Tf_2N$], $0.14molCO_2/mol\;IL$ at 1 bar, was the highest among the ionic liquids. $CO_2$ absorption capacity of ionic liquid steeply decreased with increasing temperature. Anion of ionic liquid dominates interaction with $CO_2$ and cation plays secondary role.

• Journal of the Korean Magnetics Society
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• v.2 no.2
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• pp.105-113
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• 1992

조성이 Mn$_{x}$Zn$_{1-x}$ Fe$_{2}$O$_{4}$ 훼라이트(x=0.75, 0.52)를 pusher type 연속 전기로를 이용하여 질소 분위기하에서 1360 .deg. C 로 3시간 동안 소결하여 얻어냈다. 본 연구에서는 스피넬 구조인 Mn-Zn 훼라이트의 FMR(Ferrimagnetic Resonance) 스펙트럼 특징과 초기투자율과의 상관성을 조사하고자 EPR X-band 스펙 트로미터를 이용 9.50 GHz의 microwave frequency에서 FMR 실험을 수행하였다. FMR 공명흡수선은 주 자기공명 흡 수선외에 낮은 자기장에서 약한 subsidiary 공명흡수선을 나타내는데 온도변화에 따른 주 자기공명 흡수선과 sub- sidiary 공명흡수선(제2, 제3 공명흡수선)의 세기, 공명선폭, g값 등의 온도 의존성을 연구함으로써 제2 공명흡수 선이 나타나는 원인을 분석하였으며, 자기공명 흡수선의 g값, 자기공명선 세기, 그리고 공명선폭과 초기투자율의 상관성을 연구하였다. 실험 결과 주 자기공명 흡수선의 g값, 자기공명선 세기, 공명선폭은 초기투자율 값과 밀접 한 관련이 있음을 확인할 수 있었다.었다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.6
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• pp.20-29
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• 2016

This study investigates the effect of the absorbent materials on the material properties(compressive strength and drying shrinkage) of natural hwangtoh mortar which is one of the traditional building material in Korea. The absorbent materials used are seaweed paste and Super-Absorbent Polymer(SAP). In addition to the absorbent materials, the initial sealed curing recommended by the standard specification of properties for Korean traditional building materials is also a main interest of this study. Based on the test results of 28 days compressive strength and converged drying shrinkage, it is confirmed that the initial sealed curing for 7 days is effective to reduce the drying shrinkage and to enhance the compressive strength. Thus, it is verified that the recommendation is reasonable and has positive effects on the properties of the mortar. Next, the test results show that the addition of absorbent materials into the mortar is also effective to the two properties depending on their absorption capacity. Thus, it is more effective to use SAP than the seaweed paste because of higher absorption capacity. However, both the initial sealed curing and keeping total water contents of the mortar are required to show this effectiveness. Lastly, the compressive strength is inversely proportional to the drying shrinkage. By using this relation, the reason of the increase of compressive strength due to the initial sealed curing or the addition of absorbent materials is quantitatively explained.

• Journal of Oral Medicine and Pain
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• v.32 no.1
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• pp.69-79
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• 2007

Condylar resroption, or condylysis can be defined as progressive alteration of condylar shape and decrease in mass. Although the cause is unknown, condylar resorption has been assocated with rheumatoid arthritis, systemic sclerosis, systemic erythematous, steroid usage, orthodontic treatment and orthognathic surgery. In most case, however, there is no identifiable precipitating event. Hence the term is idiopathic condylar resorption. With condylar resorption, the bone loss is resulting in a loss of posterior support in the involved condyle and the mandible can then shift. As a result, the most patients exhibit occlusal change, openbite, retrognathism, and a decrease in posterior face height. This article reports cases of condylar resorption. And the author will review factors capable of changes of condyle, pathogensis and management of conylar resorption.

• Clean Technology
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• v.18 no.1
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• pp.22-30
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• 2012

Separation of $SO_2$ from the flue gases of fossil fuel power plants are important issue because of its strong environmental impact. Industrially, $SO_2$ is being removed with a slurry of limestone, lime or aqueous caustic soda. However, these scrubbing processes possess several drawbacks such as the generation of huge amount of wastewater and the production of metal salts. Recently, ionic liquids have gained increasing interest as an absorbent for acid gas, $CO_2$ and $SO_2$. In this review, we have introduced the recent progress of ionic liquids as a $SO_2$ absorbent.

• Journal of Korean Society of Forest Science
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• v.7 no.1
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• pp.3-7
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• 1968

The Capacity of wood to absorb water is very important as the basis data for wood industry, particularly in preservatives impregnation, manufacturing of improved wood, selection of packing boards, etc. In this study differences in Water absorbing Capacity of wood by structual section, water soaking time were investigated. (1) The species used in this investigation were Larix olgensis Henry Var. Koreana Nakai and Juglans mandshurica Max., and dimension of these testing wood block was $30{\times}30{\times}100cm$; and these were soaked in fresh water of $25{\pm}1^{\circ}C$ for 8.5day and 0.5 day, before measurement. (2) The result showed that the water absorption by cross sections was greater than by either radial or tangential section and there were no differences between radial and tangential section. (3) The water absorption of Juglans mandshurica Max. which has the relatively low specific gravity was greater than Larix olgensis Henry Var. Koreana Nakai which has generally high specific gravity. (4) The result showed an increase in the absorbed water with increase in the length of soaking time. However the water absorption rate during the early period of soaking was very high and thereafter the rate decreased with passage of time. More than a half of the total water absorption was achieved during the first 2 days approximately. (5) The relationships between the length of the soaking-time and water absorption were found to be as follows : Larix olgensis Henry Var. Koreana Nakai Cross section : $y=111.1{\times}^{0.6516}$ radial section : $y=32.2{\times}^{0.5146}$ tangential section : $y=36.5{\times}^{0.5112}$ Juglans mandshurica Max. Cross section : $y=216.1{\times}^{0.5914}$ radial section : $y=27.9{\times}^{0.5832}$ tangential section : $y=50.9{\times}^{0.4769}$ Where : y is amount of water absorption ($mg/cm^2$) x is water-soaking time (days).

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1119-1122
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• 2010

본 논문에서는 상용 이온성 액체를 대체하기 위해 손쉽게 구입할 수 있는 원료물질을 사용하여 이온성 액체를 실험실 규모로 제조한 후 고압 연소전 조건에서 이산화탄소의 용해도 및 재생력을 측정하기 위해 기-액 흡수평형장치를 이용하여 연구하였다. [eeim]ethyl sulfite를 제조하여 흡수실험을 실시한 결과 흡수평형압력이 25bar의 조건에서 0.72 mol $CO_2$ /mol IL의 흡수력을 보였으며, 재생성능은 탈착 전후의 흡수력 차이가 약 9%로 우수한 편이었다. 희석제를 첨가하였을 경우 흡수력은 약 38% 감소하였으나, 합성단계가 간단하며 원료물질이 저렴한 장점을 가지고 있다.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.15-26
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• 2006

흡수성 차페막을 이용한 조직 유도 재생술시 차폐막의 견고성으로 미루어 보아 재생을 위한 공간의 유지가 어려울 수 있다. 조직 유도 재생술과 함께 골이식술을 시행함으로써 공간 확보와 함께 적절한 혈병의 유지를 도모할 수 있고 이식된 골은 선생골 형성을 위한 핵으로 작용할 수도 있다. 최근에 사람의 치아회분말과 연석고를 혼합한 골이식재가 여러 연구를 통해 좋은 골이식재로 평가되었다. 본 연구에서는 성견 하악 소구치 2급 치근이개부위에 외과적으로 형성하여 흡수성 차폐막과 치아회분말-연석고 혼합 이식재를 이용한 조직유도재생 술을 시행하여 치주 조직 재생의 양상을 조직학적으로 관찰하고자 한다. 생후 12개월에서 16개윌 된 체중 15 Kg 내외의 성견 4마리를 이용하였다. 실험 재료로 생체흡수성 차폐막 (Biogide(R), Swiss) 를 사용하였고, 골이식재로 치아회분말-연석고를 혼합매식 하였다. 양측 상악 소구치 부위에 변연 치조골하방에 4 mm ${\times}$ 4 mm ${\times}$ 4 mm, (깊이 ${\times}$ 근원심 ${\times}$ 협설폭경) 깊이로 골내낭을 형성하였다. 형성된 골내낭의 기저부위 치근 표면에 1/4 round bur로 notch를 형성하여 참고점으로 하였다. 무작위로 선택된 한 쪽의 결손부를 대조군으로 오직 생체 흡수성 차폐막을 사용하였고, 실험군으로 치아회분말-연석고와 생체 흡수성 차폐막을 결손부로부터 2 mm 이상 덮을 수 있도록 다듬어 결손부 위에 위치시킨 후 협측 판막을 덮고 봉합하였다. 4주 후 2마리 ,8주 후 2마리를 희생시키고 통상의 방법으로 고정, 탈회, 포매의 과정을 거쳐 광학 현미경으로 검경하였다. 그 결과, 1. 4주 대조군에서 Bio-gide(R)는 완전한 흡수를 보였고, 치근이개부내에는 큰 공간이 존재하였다. 2. 4주 실험군에서 역시 Bio-gide(R)는 완전한 흡수를 보였고, 골 결손부내에 더 많은 신생골 관찰되었다. 그러나 아직까진 기존골과 신생골간에 명확한 차이가 있어서 쉽게 구분할 수 있었다. 또한 골이식재 주변으로 파골세포가 다수 관찰되며 이로 미루어 보아 활발한 골흡수가 일어남을 알 수 있었다. 3. 8주 대조군에서 결손부내에서는 기존골에 인접하여 신생골 형성이 부분적으로 일어났으나 연조직 침입이 관찰되었다. 4. 8주 실험군은 신생골이 기존골과 매우 유사한 형태로 관찰되었고, 신생골 형성 부위에 신생 혈관 증식이 관찰되었다. 또한 골내낭 기저부위에서는 백악질과, 치주인대가 재생됨이 관찰되었다. 이상의 결과에서 치아회분말-연석고 혼합매식은 골재생을 위한 골전도성이 있는 재료로 사료되며, 이를 이용히여 치주조직재생술시 흡수성 차폐막과 병행하여 사용한다면 더 많은 골재생이 있을 것으로 기대된다.

• 대한치주과학회:학술대회논문집
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• 1999.11a
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• pp.91-92
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• 1999