• Journal of Mushroom
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• v.5 no.2
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• pp.76-80
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• 2007

After bottle culture of Pleurotus eryngii, media were taken out the bottle and normally utilized compost. However, nutritional elements were remained in the waste media. This study was carried out to investigate the reusable possibility and the optimal additive rate of waste media in an artificial cultivation of Pleurotus eryngii. The pH had tendency to decrease as the waste media was added from 6.0 to 4.8. Based on the additive rate of 10, 20, 30, 40, and 50%, each treatment waste media was added to new media for culturing Pleurotus eryngii. Among various treatments, the mycelial growth and primordia formation of Pleurotus eryngii were more favorable in the addition of 10-30% waste median than in the addition of 40 and 50%. The yield of its fruiting body was increased slightly in the treatment of 10-30% waste media.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.543-549
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• 2000

Gutta-percha와 근관sealer를 사용한 근관 충전은 가장 많이 이용되고 성공률이 높은 방법이지만, 현재 사용되는 모든 근관sealer는 미세누출을 나타낸다. 따라서 더 효과적인 근관 폐쇄를 이루기 위한 재료 및 방법들이 연구되어왔다. 이중 상아질 접착제는 근관 충전재와 함께 사용되어 미세누출을 감소시키지만, 근관 내에 사용하기에 술식이 복잡하고 기술이 요구된다. 본 연구의 목적은 gutta-percha와 레진계 근관 sealer로 충전한 근관에서 self-etching primer를 미리 도포한 경우와 도포하지 않은 경우의 치근단 미세누출을 비교하고, self-etching primer를 도포함에 있어 근관 내에 적용하는 방법에 따른 미세누출을 비교하는 것이다. 또한 근관sealer와 상아질 계면을 주사전자현미경으로 관찰하여, 이 결과를 미세누출과 관련시켜보고자 하였다. 36개의 발거된 사람의 단근치에서 치관부를 절단, 제거하고 ProFile로 근관 형성한 후, 무작위로 선택하여 4개의 군으로 분류하였다. 1군에서는 주사기와 30게이지 주사 바늘로 self-etching primer를 근관 내에 적용하였고, 2군에서는 self-etching primer를 paper point에 적셔 근관 내에 적용하였다. 3군에서는 self-etching primer를 적용하지 않았다. 1, 2, 3군의 치아를 gutta-percha와 AH26 sealer를 사용하여 continuous wave 충전법으로 충전한 후 치근단공 주위 3mm를 제외한 치근변에 nail polish를 2회 도포하였고, 4군(음성 대조군)은 치근면 전체에 도포하였다. 1군과 2군에서 각각 2개의 치아는 주사전자현미경적 관찰을 위해 준비하였다. 모든 치아를 Methylene Blue 수용액에 48시간동안 침적, 수세한 후 치아 장축에 평행하게 양분하여 10배의 실물확대현미경 하에서 치근단 색소 침투를 관찰하였다. Self-etching primer를 도포한 군과 도포하지 않은 군 사이에는 평균 미세누출량에 유의한 차이가 없었다. 주사 바늘로 적용한 군과 paper point로 적용한 군 사이에도 평균 미세누출량에 유의한 차이가 없었다. 상아질과 근관 sealer계면의 주사전자현미경 관찰 결과 일부분에서 긴밀한 접착 관계를 나타내었고, 다른 부분에서는 간극을 나타내었다.

• Korean Journal of Organic Agriculture
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• v.15 no.3
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• pp.319-330
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• 2007

This study analyzed physical and chemical characteristics of peat soil to use peat soil as the materials fur pot media and investigated seedling quality of horticultural plants in order to use peat soil as the raw materials fur pot media. The summary of the results is as follows; The chemical characteristics of peat soil, which is main ingredient of pot media are as follows; pH was 4.9, EC was less than $2.0ds{\cdot}m^{-1}$, which interferes the growth of the plant and organic ingredient was 33%. When looking into the germination characteristics of plants according to the mixture of pot media, red pepper showed 54.2% speed of germination and 97% germination rate in peat soil single treatment. Therefore the peatsoil was appropriate for the pot media for red pepper. In case of cucumbers, in the 50 : 50 treatment of main ingredient (peat soil) and auxiliary ingredients (vermiculite, peat moss and perlite) they showed 100% speed of germination and 100% germination rate. Therefore 50 : 50 treatment was appropriate fur the pot media for cucumbers. In case of chinese cabbage, peat soil, perlite and peat moss mixture (50 : 25 : 25) treatment showed the highest speed of germination (77.5%), while the germination rate was a little lower (92.15%) than comparative soil. However, it was appropriate for the pot media for chinese cabbage. In case of watermelon, germination was bad because of the influence of EC when the teat soil ingredient is over 80%. However, in the mixture of peat soil and vermiculite (50:50) treatment, they showed 91.6% speed of germination and 100% germination rate. Therefore it was appropriate for the pot media for watermelon. When looking into the growth of the plants according to the mixture of ingredients, peat soil and perlite (50:50) mixture showed excellent seedling quality for cucumbers, peat soil and perlite (50:50) mixture showed excellent seedling quality and it was proven to be appropriate for the pot media for cucumbers. In case of watermelon, peat soil, peat moss and perlite (80 : 10 : 10) mixture showed excellent seedling quality and it was proven to be appropriate for the pot media for watermelon.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.673-682
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• 2001

The use of resin composites has continued to increase over the last several years. In spite of their growing popularity, composites continue to exhibit a number of undesirable characteristics. One of the major deficiencies of composite restorative resins is their inadequate resistance to wear. Of the multitude of factors that have been associated with wear, subsurface degradation within the restoration is considered to be one. The aim of this study was to evaluate the resistance to degradation of four commercial composite resins in an alkaline solution. This solution with a high concentration of hydroxyl ions is a convenient medium for accelerated degradation of silane coupling and filler particles. The brands studies were Definite($Degussa-H\ddot{u}ls$ AG, Germany), Prodigy(Kerr, USA), Pyramid(Bisco, USA) and Synergy(Coltene, Swiss). Preweighed discs of each brand were exposed to 0.1N NaOH solution at $60^{\circ}C$. After 14 days they were removed, neutralized with HCl, washed with water and dried. Resistance to degradation was evaluated on the basis of following parameters : (a) mass loss(%)-determined from pre-and post-exposed specimen weights : (b) Si loss(ppm)-obtained from ICP-AE analysis of solution exposed to specimens; and (c) degradation $depth({\mu}m)$-measured microscopically (SEM) from polished circular sections of exposed specimens. The results were follows: 1. Mass loss of Synergy was $1.24{\pm}0.002%$, it was the highest, there was no significant difference among the materials. 2. The degree of degradation layer depth of Synergy was $107.83{\pm}2.52{\mu}m$, it was the highest, there was no significant difference among any other materials than Synergy. 3. There was no difference among the four materials in Si loss. 4. The correlation coefficient between mass loss and degradation depth was relatively high(r=0.06, p<0.05). 5. There was no coefficient correlation between Si loss and mass loss, the degree of degradation layer depth and Si loss. 6. When observed with SEM, destruction of bonding is observed between resin matrix and filler.

• Journal of Food Hygiene and Safety
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• v.31 no.3
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• pp.153-166
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• 2016

The purpose of this study was to investigate consumers' perceptions on monosodium L-glutamate (MSG) in social media. Data were collected from Naver blogs and Naver web communities (Korean representative portal web-site), and media reports including comment sections on a Yonhap news website (Korean largest news agency). The results from Naver blogs and Naver web communities showed that it was primarily mentioned MSG-use restaurant reviews, 'MSG-no added' products, its safety, and methods of reducing MSG in food. When TV shows on current affairs, newspaper, or TV news reported uses and side effects of MSG, search volume for MSG has increased in both PC and mobile search engines. Search volume has increased especially when TV shows on current affairs reported it. There are more periods with increased search volume for Mobile than PC. Also, it was mainly commented about safety of MSG, criticism of low-quality foods, abuse of MSG, and distrust of government below the news on the Yonhap news site. The label of MSG-no added products in market emphasized "MSG-free" even though it is allocated as an acceptable daily intake (ADI) not-specified by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). When consumers search for MSG (monosodium L-glutamate) or purchase food on market, they might perceive that 'MSG-no added' products are better. Competent authorities, offices of education and local government provide guidelines based on no added MSG principle and these policies might affect consumers' perceptions. TV program or news program could be a powerful and effective consumer communication channel about MSG through Mobile rather than PC. Therefore media including TV should report item on monosodium L-glutamate with responsibility and information based on scientific background for consumers to get reliable information.

• Computational Structural Engineering
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• v.8 no.4
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• pp.87-97
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• 1995

For the same configuration of two-dimensional finite element models, 6-node element exhibits stiffer bending stiffness than 8-node element. This is true in the relation between 16-node element and 20-node element for three-dimensional model. This stiffening phenomenon comes from the elimination of several mid nodes from full-node elements. Therefore, this may be called 'relative stiffness stiffening phenomenon'. It seems that there are a couple of ways to correct the stiffening effect, however, we could find only one effective method-the method of modification of Gauss sampling points-which passes the patch test and does not alter other kinds of stiffness, such as extensional stiffness. The quantity of modification is a function of Poisson's ratios of the constituent materials. We could obtain two modification equations, one for plane stress case and the other for plane strain case. This method can be extended to 3-dimensional solid elements. Except the exact plane strain cases, most 3-dimensional plates could be modeled successfully with 16-node element modified by the equation for the plane stress case. The effectiveness of the modification method is checked by applying it to several examples with excellent improvements. In numerical examples, beams with various boundary conditions are subjected to static and time-dependent loads. Free and forced motion analyses of beams and plates are also tested. The beam and plate may be composed of isotropic multilayers as well as a single layer.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.1
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• pp.23-29
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• 2020

Purpose: The purpose of this retrospective study was to evaluate the method using the S-reamer and gel-type graft material by the success rate and survival rate. Materials and methods: Implantation period was from 2008 to 2014, Follow check up year is 2019. There were 59 patients and 117 implants. All implants were placed in the posterior maxilla with the sinus lift. The patients population consisted of 34 men and 25 women, ranging from 19 to 75 years. The residual bone heights were from 1 mm to 6 mm. Sinus was perforated with S-reamer without membrane tearing and gel type bone graft material was used for membrane lifting and filling the space. all implants were placed simultaneously. Panoramic X-ray was taken. After 5 - 6 months healing period, final prostheses were restored. After more 5-years implant surgery, Panoramic X-ray was obtained and X-ray analysis and clinical examination were performed. Success criteria was referred to a Buser's success critera. All implants were classified to success implant, survival implant, failed implant. A success implant was satisfying success criteria, a survival implant was a implant that was acute infection with suppuration and bone loss, a failed implant was a implant that was mobile, removed. Results: Five implants were removed, and 4 implants had infected with bone loss. Survival rate was 95.7% and success rate was 92.3%. Conclusion: This retrospective study presented that this method with S-reamer and gel-type graft material was a successful treatment without membrane tear in the condition of 1-6 mm residual bone height.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.66-66
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• 2010

국내 화력발전의 $CO_2$배출량을 크게 줄이고, 친환경, 그린 화력발전시스템을 위한 가장 효과적인 수단은 발전효율을 획기적으로 증대시키는 것이기 때문에 이를 목표로 한 기술개발은 경제적으로나 산업적으로 파급효과가 매우 크다. 발전효율 증대를 위한 핵심기술은 증기터빈의 성능향상이다. 현재 일본, 미국, EU 등 각국이 가장 관심을 가지고 기술개발에 심혈을 쏟고 있는 초내열, 내식 합금소재는 $700^{\circ}C$이상에서 기계적 성능을 보장할 수 있는 Ni기 합금개발이고, 현재까지 상당한 기술수준에 이르고 있는 것으로 파악되고 있다. 국내의 경우는 관련기술개발을 위해 연구가 진행되고 있으나, 기술적으로 아직 미흡한 수준이다. Ni기 초내열, 내식합금을 개발해서 그것을 화력발전용 증기터빈 부품, 특히 초내열합금 용접형 터빈로터 소재로 이용하기 위해서는 체계적이고 실용적인 연구를 통하여 용접형로타의 내구성과 신뢰성이 보장되는 최적 수준의 접합기술 개발이 선행되어야 한다. 따라서 본 연구는 선행연구로 $700^{\circ}C$이상 초내열/내식 Ni기 합금소재의 용접기술 개발을 위한 후보 소재 Alloy 617의 동종재료 용접 기술 개발을 목표로 한다. 본 연구는 Alloy617 12.6t 맞대기 이음으로 U그루브 내로갭 TIG용접을 하였다. 1pass 1layer 방식으로 총 8pass 8layer로 용접하였다. 전류 및 용접속도는 동일하게 두고 실드가스를 Ar 또는 Ar-$H_2$ 가스로 변경하여 시험하였다. Ar가스 TIG용접은 비드표면에 산화스케일이 생기고, 비드면이 거칠며 전체적으로 산화되었다. 반면에 Ar-$H_2$가스 TIG용접은 비드표면에 산화스케일이 없으며 표면이 미려하고 산화되지 않았다. 실드가스에 수소가스 첨가시 환원성가스로 역할을 하게 되고 이에 따라 용융지 표면에 산화피막을 제거하여 용접비드를 청정하게 하는 효과를 가진다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.875-888
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• 2013

The researches have recently progressed toward the use of the superelastic shape memory alloys (SMAs) to develop new smart control systems that reduce permanent deformation occurring due to severe earthquake events and that automatically recover original configuration. The superelastic SMA materials are unique metallic alloys that can return to undeformed shape without additional heat treatments only after the removal of applied loads. Once the superelastic SMA materials are thus installed at the place where large deformations are likely to intensively occur, the structural system can make the best use of recentering capabilities. Therefore, this study is intended to propose new buckling-restrained braced frames (BRBFs) with superelastic SMA bracing systems. In order to verify the performance of such bracing systems, 6-story braced frame buildings were designed in accordance with the current design specifications and then nonlinear dynamic analyses were performed at 2D frame model by using seismic hazard ground motions. Based on the analysis results, BRBFs with innovative SMA bracing systems are compared to those with conventional steel bracing systems in terms of peak and residual inter-story drifts. Finally, the analysis results show that new SMA bracing systems are very effective to reduce the residual inter-story drifts.

• Fire Science and Engineering
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• v.31 no.6
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• pp.23-32
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• 2017

Foam block, popularized as the self-interior goods, is susceptible to fire since the main material is the polyethylene flammable synthetic resin. However, it is widely used in homes, offices, and multi-use facilities. In order to understand the fire characteristics of the foam block, two kinds of foam blocks sold in the market (non-fire retardant and fire retardant) were evaluated according to standard of KS F 5660-1 (Reaction to fire test). In addition, the hazard analysis of the gas generated by the combustion of the specimen was performed using the FTIR gas analyzer. The cone calorimeter test showed that the ignition and flame combustion of both two specimens were burned as soon as the radiant heat blocking device was removed, and it was confirmed that the flame could become a rapid propagation factor during the fire. The analysis of the combustion gas through the FTIR gas analyzer showed that both the carbon dioxide and carbon monoxide classified as the common combustion gases and the acrolein, ammonia, and hydrogen cyanide causing serious damage to the human body were detected substantially. This study showed that a foam block product has high ignitionability and generates toxic gases. Hence, it is urgently required to establish the standards used for properly classifying the combustion characteristics of the material on the basis of the use conditions of a foam block product and to prepare the standards on the purpose of use.