• 한국환경복원기술학회지
• /
• 제17권1호
• /
• pp.1-12
• /
• 2014

This study was carried out not only to identify the optimum concentrations of sulfur powder and citric acid treated for improving arsenic absorption of Pteris multifuda known as hyperaccumulator of arsenic, but also to develop arsenic purification model in the forest soil. After applying sulfur powder (0, 30, 45, $60g{\cdot}m^{-2}$) and citric acid (0, 200, 400, $800g{\cdot}m^{-2}$) in the forest soil contaminated with heavy metals, P. multifuda was planted and cultivated for 16 weeks. And then the growth and arsenic contents of plants were analyzed. In the result of research, the growth of P. mulifuda, except plant width, cultivated in soils treated with sulfur powder and citric acid was relatively lower than control. The accumulated amount of arsenic in aerial parts of P. multifuda ($1822.2mg{\cdot}kg^{-1}$) cultivated in soils treated with $200g{\cdot}m^{-2}$ citric acid was improved 62.5% against the control. And the accumulated amount of arsenic per 1 $m^2$ ($20.1mg{\cdot}m^{-2}$) was the greatest in $200g{\cdot}m^{-2}$ citric acid treatment. Translocation rate (TR) was higher in all acid treatment compare to control, and was the best in $200g{\cdot}m^{-2}$ citric acid treatment (0.95) especially. It showed that the arsenic absorbed in underground parts was transferred fast to aerial parts. Therefore, $200g{\cdot}m^{-2}$ citric acid treatment in the soil is recommended for arsenic purification using P. multifuda.

• 한국터널지하공간학회 논문집
• /
• 제21권6호
• /
• pp.887-895
• /
• 2019

인구 초과밀화 현상이 심해지고 있는 국내 수도권 및 대도시에서 발생되고 있는 교통문제 해결을 위해 지하도로 개발 사업이 늘어나고 있으며, 시공성과 경제성의 이점을 가지는 복층터널 기술을 적용하여 다수의 지하도로를 계획하고 있는 추세이다. 복층터널은 하나의 굴착단면을 두 개로 나눠 상하행선으로 사용하는 방식으로 대부분 층고가 낮아 소형차량 전용도로로 사용되고 있는 실정이다. 또한, 이러한 소단면 특성으로 인해 환기 및 방재 측면에서도 일반 도로터널과 상이한 특성을 가지게 된다. 본 연구에서는 복층터널과 같이 층고가 낮은 소단면 터널에 반횡류식 환기방식의 하나인 대배기구 방식을 적용한 운영안을 제시하고 FDS 시뮬레이션을 통해 화재발생 위치와 대배기구 배연 방식 등에 따른 배연 특성을 비교하여 분석하였다. 그 결과 균일배기와 달리 대배기구를 이용하여 집중배연시 연기의 확산지연 효과가 최대화 되고 연기가 화재지점 상하류 50 m안에 제한시킬 수 있었다.

• 한국약용작물학회지
• /
• 제26권3호
• /
• pp.227-232
• /
• 2018

Background: Angelica gigas Nakai is a perennial herb belonging to the family Umbelliferae. Its roots are utilized in traditional medicine. The aim of this study was to increase the yield of and the content of two indicator components (decursin and decursinol angelate) in A. gigas Nakai. Methods and Results: The roots of A. gigas Nakai were harvested 4-times from late August to late October in 2017. Two agents (trace element-TE, and plant hormone-HM) were applied 4 times at intervals of 2 weeks. The content of the two indicator components were analyzed by high performance liquid chromatography. The HM treatment showed the greatest increase in underground part yield and root diameter. The content of the two indicator components in the control (non-treatment) group was the highest in the underground part, but was higher in the aerial parts in the agent treatment group. After treatment with the agents, the content of the indicator components tended to decrease in the underground part. However, the total content of the indicator components in the two agent treatment groups exceeded the level of 6% set by the Korean Pharmacopoeia. Conclusions: The highest underground part yield was found in the HM treatment group, while the highest content of decursin and decursinol angelate were found in the control group. This study provides basic information for yield improvement in A. gigas.

• 한국건축시공학회지
• /
• 제19권5호
• /
• pp.411-419
• /
• 2019

지하 콘크리트 구조물은 지하라는 지리적 환경 하에 건축되어 열화를 촉진하는 다양한 환경에 노출되어져 있다. 그 중 지하수는 대표적인 열화를 촉진시키는 환경 중 하나로 지상으로부터 전달되는 오염수(공장폐수, 농약, 하수 및 분뇨, 대기 중의 중금속 빗물 등)로 인하여 지하 콘크리트 구조물에 열화를 더욱더 가중시키고 있다. 이에 본 연구에서는 균열부위에 사용되는 누수보수재료에 대한 화학 안정화 판단을 위하여 우리나라 누수보수 시공 현장에서 일반적으로 사용되고 있는 5계열(합성고무계, 시멘트계, 에폭시계, 아크릴계, 우레탄계)의 각 3Type 씩 총 15Type의 누수보수재료에 대한 5가지 수용액(염산, 질산, 황산, 수산화나트륨, 염화나트륨)의 화학저항성능 시험평가를 실시하였다. 그 결과 대체로 대부분의 화학 수용액에서 증감이 나타나고 있지만, 큰 증감을 보여 주고 있는 것은 아크릴계는 염화나트륨과 수산화나트륨에서 확인 되었고, 에폭시계는 염산과 질산에서 나타났다. 시멘트계는 염화나트륨에서 많은 증감을 보여 주고 있다. 이러한 연구 결과를 토대로 신누수보수재료 개발의 화학 안정화를 위한 근간으로 활용되기를 기대한다.

• 화약ㆍ발파
• /
• 제39권4호
• /
• pp.22-33
• /
• 2021

최근 도시지역의 지반침하가 빈번하게 발생하여 주민들의 불안이 증가하고 막대한 사회적 비용이 발생하고 있다. 지반침하의 원인 중 노후 상하수도관의 파열은 매설관의 가동을 정지시킬 뿐만 아니라 지반 및 수질오염 문제를 야기한다. 그러나 대부분의 파이프는 시공 후 매설되어 육안으로 볼 수 없기 때문에 다른 구조물에 비해 유지보수의 중요성이 저평가되고 있다. 최근 몇 년 동안 지하 파이프 및 구조물의 유지 보수에 통합 물리적 탐사가 적용되었다. 현재 지하 공간 내부와 지반취약점을 조사하기 위해 통합물리조사를 실시하고 있다. 통합물리조사는 여러 가지 물리조사를 이용하여 다양한 물성자료를 얻고 기존 자료를 추가하는 분석기법이다. 일반적으로 지반 공학에서는 전기 및 표면파 조사를 포함한 통합 물리 조사가 채택되지만, 이러한 조사를 이용하여 지하 공간의 시간적 변화를 조사하는 것은 어렵다. 이에 반해 원자로 내부를 스캔하기 위한 투과기술로 우주선 뮤온을 이용한 탐사가 이루어지고 있다. 뮤온을 이용한 측량은 진동이나 전기의 영향 없이 실시간 관찰이 가능하다. 이러한 조사는 많은 노동력을 요구하지 않고 밀도 분포를 조사할 수 있기 때문에 활용 가능성 측면에서 큰 잠재력을 가지고 있다. 본 논문에서는 우주선 뮤온을 이용한 측량 기술을 소개하고, 이러한 기술을 지하 공간 및 지하 구조물에 대한 새로운 물리 측량 기술로 적용할 가능성을 제시한다.

• 생약학회지
• /
• 제41권4호
• /
• pp.233-237
• /
• 2010

The crude drug 'CheonKun' is derived from the underground portions of Rubia species. However, the aerial parts of the plants are also sold under the 'GgogDuSeoNiIp' in Korea. To clarify the botanical origin of 'GgogDuSeoNiIp' the morphological and anatomical characteristics of the leaves of Rubia species growing in Korea, i.e. Rubia akane, R. chinensis var. glabrescens, R. cordifolia var. pratensis were compared. As a result, it was determined that 'GgogDuSeoNiIp' was the leaf of Rubia akane and R. cordifolia var. pratensis.

• Tribology and Lubricants
• /
• 제22권4호
• /
• pp.225-229
• /
• 2006

The issue with the drainpipe now a day is that they are laid underground. Causing us to perform additional work to repair, such as digging up the ground and peeling off the insulator that surrounds the pipe. And such series works are difficult that concession appears from government and municipal office. However, if we can save time and money. Performance of piping robot that we are studied in existing session through fixing unit and improvement of cutting bit shorten and wished to heighten work efficiency. And we are trying to develop a unit that can cut up the projecting parts which connects with the interior part of the drainpipes.

• Journal of Radiation Protection and Research
• /
• 제41권2호
• /
• pp.141-147
• /
• 2016

Background: A project for building a neutron time-of-flight (nTOF) facility is progressing. We expect that the construction will start in early 2016. Before that, a detailed simulation based on the current architectural drawings was performed to optimize the performance of our facility. Materials and Methods: Currently, several parts had been modified or changed from the original design to reflect requirements such as the layout of the electron beam line, shape of the vacuum chamber producing a neutron beam, and the underground layout of the nTOF facility. Detailed analysis for these modifications has been done with MCNP simulation. Results and Discussion: An overview of our photo-neutron source and KAERI nTOF facility were introduced. The numerical simulations for heat deposition, source term, and radiation shielding of KAERI nTOF facility were performed and the results are discussed. Conclusion: We are expecting that the construction of the KAERI nTOF facility will start in early 2016, and these results will be used as basic data.

• Tribology and Lubricants
• /
• 제25권3호
• /
• pp.182-186
• /
• 2009

Extruders can be basically divided into bisk and screw type of extruders. Though plastic extruders are often used for its simplicity for water and oil transportation pumps, these days screw extruders are mostly used. Screws are used in many extrusion processes to manufacture complex and complicated shaped parts made of plastics, medicine materials, food, polymer composites, iron and ceramic powders, etc. Also, material correction of deformities is caused by flow and physicochemical reaction phenomenonand material extrusion is processed according to heat transfer. various material comes to hopper because extruder has function by blender and mixing of materials can go well before come out through dice. These change process is so complicated that process condition is decided by trial and error that process condition is underground mainly at extrusion molding process.

• Natural Product Sciences
• /
• 제16권3호
• /
• pp.175-179
• /
• 2010

The present study aimed to assess the antifungal properties of the essential oil fraction from Ligusticum chuanxiong (Umbelliferae) and its components against five clinically important Aspergillus species. The essential oil fraction was extracted from the underground parts of the plant by steam distillation, and its main components, namely, Z-ligustilide, butylidene phthalide, and p-cresol were isolated by column chromatography. The antifungal activities of the essential oils were evaluated by the broth dilution method. Both the total essential oil fraction of L. chuanxiong and its components showed significant anti-Aspergillus activity against all five tested strains with MICs between 62.5 and 250 ${\mu}g$/ml, respectively. In a checkerboard microtiter assay, the combination of antibiotics, itraconazole with the essential oil fraction of L. chuanxiong or its main components exhibited synergistic or additive, and in some cases indifferent, effects against the tested Aspergillus species, resulting in FICIs (fractional inhibiting concentration indices) ranging from 0.12 to 2, while the combination of antibiotics, amphothericin B with L. chuanxiong essential oils mostly showed antagonistic effects.