북한산국립공원의 계류수질 보전 전략(I)

박재현,우보명,김우룡,안현철,조현서,추갑철,김춘식,최형태,Park, Jae-Hyeon,Woo, Bo-Myeong,Kim, Oue-Ryong,Ahn, Hyun-Chul,Cho, Hyun-Seo,Choo, Gab-Chul,Kim, Choon-Sig,Choi, Hyung-Tae 한국환경복원기술학회 2001 한국환경복원기술학회지 Vol.4 No.3

This study was conducted to investigate physicochemical property changes from July 1998 to August 2001 in Mt. Bukhansan National Park. Four water sampling points were selected to measure the quality of stream water in the northeastern part of the Mt. Bukhansan National Park. The results were summarized as follows; In spring, the average pH of stream water was below the first class of the river water quality standard, while it was normal level in summer. The average electrical conductivity was about 2.3~3.3 times higher in downstream water than in upstream water during spring and summer. The contents of anions($Cl^-$, $NO{_3}^-$, $SO{_4}^{2-}$) were about 1.1~7.4 and 0.4~11.4 times higher in downstream than in upstream water, respectively. These results indicate that water quality was poorer in downstream than in upstream water. We suggest that stream water in the Mt. Bukhansan National Park should be protected from impacts of snow melting mineral particles in spring season and human impacts like wastewater of point source in summer season.

북한산국립공원 북동사면에서 동결융해침식 및 토사유출이 계류수질에 미치는 영향

박재현(Jae Hyeon Park) 한국산림과학회 2001 한국산림과학회지 Vol.90 No.4

This study was conducted to investigate influences of solifluction and sediment runoff on the stream water qualities during the spring season. The study sites were four points in the northeastern area of the Bukhansan National Park. And, field surveys were carried out in the spring of 1999, 2000 and 2001. The results of this study were summarized as follows; During the investigation period, the amounts of sediment caused by solifluction on stream side slopes in the downstream were 1.3∼1.7 times as large as those in the upstream. The pH of sediment caused by solifluction was a potential influence on the pH of stream water. Amounts of dissolved Cl^-, NO₃^- and SO₄^(2-) in stream water were proportion to the average amounts of Cl^-, NO₃^- and SO₄^(2-) in the sediment caused by solifluction. In the spring, the average pH of stream water was lower than the first class of the river water quality standard because of increasing chemical concentration as well as the contents of anions(Cl^-, NO₃^- and SO₄^(2-)) in the spring season. Also, the average electrical conductivity of water in downstream was about 2.3-3.3 times higher than that in upstream. The amounts of anions(Cl^-, NO₃^- and SO₄^(2-)) of water in downstream were about 1.2∼7.4, 1.1∼3.9, 1.1∼1.4 times higher than those in upstream, respectively. Therefore, these results showed that the water quality of downstream was worse than that of upstream. As a result of regression analyses, the linear and exponential equation of pH and water quantity was pH = 1.7926 × stream water quantity + 5.9577(R² = 0.46), and those of electrical conductivity and water quantity was EC = 34.417e^(3.6334 × stream water quantity(m/sec) (R² = 0.44).

지리산국립공원내 칠선계곡 탐방로의 회복에 관한 분석

박재현 ( Jae Hyeon Park ) 한국환경보건기술학회(구 한국환경복원녹화기술학회) 2010 한국환경복원기술학회지 Vol.13 No.2

To investigate the restoration procedure on soil physical properties at the surface of visiting road affected by rest-year system. This study was carried out at visiting roads of stream of Chilsun in Jirisan. Mean soil strength in 20cm of soil depth was lower in the Rest-Year System areas (1.5-1.9 times in Site 2, 1.1-7.5 times in Site 3) than in the control (Site 1). Soil strength was recovered by the Rest-Year System in the national park. Mesopore rate (pF 2.7) in 0-15 cm of soil depth was higher in the Rest-Year System areas (1.2 times) than in the control. This indicates that mesopore rate is rapidly restoring in the Rest-Year System areas. Pore space rate in 0-7.5 cm of soil depth was higher in the Rest-Year System areas (23.2% in Site 2, 23.6% in Site 3) than in the control (22.4% in Site 1). Pore space rate in 7.5-15 cm of soil depth was also higher in the Rest-Year System areas (22.9% in Site 2 and Site 3) than in the control (18.9% in Site 1). Soil pore space was remediable by the Rest-Year System. Bulk density in 0-7.5 cm of soil depth was lower in the Rest-Year System areas (1.674g/cm3 in Site 2, 1.668g/cm3 in Site 3) than in the control (1.723g/cm3 in Site 1). Bulk density in 7.5-15 cm of soil depth was lower in the Rest-Year System areas (1.785g/cm3 in Site 2 and 1.721g/cm3 in Site 3) than in the control (1.721g/cm3 in Site 1). Soil bulk density was decreased in the Rest-Year System areas of the national park. Amount of soil erosion was lower in the Rest-Year System areas (0.017m3/km/yr in site 2, 0.023m3/km/yr in site 3) than in the control (0.054m3/km/yr in site 1).

일본(日本)에서 한류변(漢流邊)의 환경부원(環境復元) 발전전략(發展戰略)(I)

박재현,우보명,이헌호,Park, Jae-Hyeon,Woo, Bo-Myeong,Lee, Heon-Ho 한국환경복원기술학회 2000 한국환경복원기술학회지 Vol.3 No.1

This study was carried out to introduce current status and development strategy for an environmental restoration of stream side in Japan, and to consider a methodology which could be effectively applied for the environmental restoration of stream side in Korea. Since the end of 20th century, the native ecology and landscape of Japan remained only a limited areas such as stream side, water side and forest areas. Therefore, recently the works of forest conservation and erosion control of environmental restoration on stream side tended to increased. The strategic prospects of environmental restoration in Japan were summarized as follows : 1. From the ecological point of view, we have to develop a certain method and technology in construction of forest conservation and erosion control to prevent environmental problem from erosion control works. 2. We have to restore not only a continuity of stream side forest from a primitive area to an estuary but also the stream side forest to preserve and restore a stream side vegetation on a primitive watershed areas. 3. We have to improve a method of construction or removal of a structure which were constructed in the stream to restore a water side environment and an interaction system for an integration on a forest land, stream, and erosion control. Additionally, we have to establish an integrated evaluation method and an enforcement system after investigation of influences on natural environment, stream, and forest etc. 4. We have to conduct an integrated research to investigate the ecosystem of stream side, and construct environmentally friendly water park and erosion control park which considered natural environment and its landscape. Additionally, we need to introduce and adopt a natural style stream construction method to restore a water side areas.

TNT 처리에 관한 연구동향

박재현,신원모,이재우,Park, Jae Hyun,Shin, Won Mo,Lee, Jae W. 한국군사과학기술학회 2016 한국군사과학기술학회지 Vol.19 No.1

Over the decades, TNT has been produced indiscriminately to be utilized in many fields owing to its ability to manipulate the explosion. Yet, the proper technique for disposal of TNT and the waste residues had not been developed so that the large amount of TNT waste was being piled up. Upon the agreement to demilitarization of old weapon, a study on the disposal methods for TNT and the waste treatment have been raised for their dangerous nature. Since then, from burying in landfill to utilizing supercritical fluid-based oxidation, a lot of research is actively ongoing, but little progress has been made in Korea compared to developed countries. This review paper covers all the technologies developed for TNT and its waste disposal including the concept, advantage, and disadvantage of those technologies. Also, suggested here are the future research directions.

PZT 파우더 첨가에 따른 티타늄 파우더/폴리머 콘크리트 복합재료의 진동 특성 및 압축 물성 분석

박재현,김석룡,김경수,김건,김석호,이범주,정안목,안종욱,김선주,이시맥,유형민,Park, Jaehyun,Kim, Seok-Ryong,Kim, Kyoung-Soo,Kim, Geon,Kim, Seok-Ho,Lee, Beom-Joo,Jeong, Anmok,An, Jonguk,Kim, Seon Ju,Lee, Si-Maek,Yoo, Hyeong-Min 한국복합재료학회 2022 Composites research Vol.35 No.3

In this study, Ti powder/Polymer concrete composites were processed by adding the PZT powder, one of the piezoelectric materials, to improve the vibration damping effect of Polymer concrete. Ti powder was added at a constant ratio in order to maximize the vibration damping effect using the piezoelectric effect. Three types of composite material specimens were prepared: a specimen without PZT powder, specimens with 2.5 wt% and 5 wt% of PZT powder. The vibration characteristics and compression properties were analyzed for all specimens. As a result, it was confirmed that as the addition ratio of PZT powder increased, the Inertance value at the resonant frequency decreased due to the piezoelectric effect when the vibration generated from Ti powder/polymer concrete was transmitted. Especially, the Inertance value was decreased by about 19.3% compared to the specimen without PZT at the resonant frequency. The change in acceleration with time also significantly decreased as PZT powder was added, confirming the effect of PZT addition. In addition, through the compression strength test, it was found that the degree of deterioration in compression properties due to the addition of PZT up to 5 wt% was insignificant, and it was confirmed that the powder was evenly dispersed in the composites through the cross-sectional analysis of the specimen.

전형적(典型的)인 학질의 증례(證例) 보고(報告)

박재현,Park, Jae-Hyun 대한한방내과학회 1998 大韓韓方內科學會誌 Vol.19 No.2

This study was performed on the bases of clinical consideration about patient who has malaria. The symptoms of malaria are periodic alternating of chills and fever on everyone, two or three days. The patients feel a chill at the first time of malaria, and have a fever, headache and sweating at the next time. The long cycle of malarial fever such as every 2 or 3 days means that it takes a turn for the worse. In this study, oriental medicine was taken based on the oriental medicine principle such as Dalwonum(達原飮), Sosihotang(小柴胡湯) and Bojungikgitang(補中益氣湯), and the patients take a turn for the better. In the process of treatment if there is no fever in the expected date of the malarial fever, it is sure to have fever in the next expected date. It is favorable that patients lose the chills first and the fever lately in the process of treatment, and we can explain that supporting healthy energy to eliminate evil(扶正祛邪). The long cycle of malarial fever such as every 4, 6 or 9 days means that it is just before the recovery.

회전근 개 파열의 수술적 치료시 초음파 연속 검사의 유용성

박재현,최원기,최창혁,Park, Jae-Hyun,Choi, Won-Ki,Choi, Chang-Hyuk 대한정형외과초음파학회 2008 대한정형외과 초음파학회지 Vol.1 No.2

목적: 회전근 개 파열 환자에서 수술 전의 자기 공명 영상 검사와 초음파 검사에 따른 관절경 소견을 비교하고, 수술 후 2주, 6주 및 3개월의 회전근 개의 건재 상태를 초음파로 확인하는데 있다. 대상 및 방법: 2008년 2월부터 5월까지 본원 정형외과에 내원하여 회전근 개 파열로 관절경적 치료를 시행한 환자 29명을 대상으로 초음파 검사와 자기 공명 영상 검사를 시행한 후 관절경적 시술을 이용하여 비교하였으며, 수술 후 2주, 6주 및 3 개월에 회전근 개의 건재 상태를 초음파를 이용하여 관찰하였다. 결과: 회전근 개 파열을 확인할 수 있는 초음파 검사와 자기 공명 영상 검사의 예민도는 각각 100%였다. 전층 회전근 개 파열에서 초음파 검사와 자기 공명 영상 검사의 예민도는 각각 95%, 82%였으며, 부분층 회전근 개 파열에서 초음파 검사는 50%, 자기 공명 영상 검사는 33%의 예민도를 나타내었다. 전체 환자에 대한 초음파 검사의 정확도는 86%, 자기 공명 영상 검사의 정확도는 69%이었다. 전층 회전근 개 파열로 복원술을 시행한 22예 중 수술 후 2주에 시행한 추시 관찰 초음파 검사상 11예(50%, 소 및 중 파열 2예, 대 및 광범위 파열 9예)에서 회전근 개의 봉합 부위에서 수술 소견과 일치하는 틈새로 진단되는 저에코를 확인할 수 있었으며, 수동적 신장 운동을 시행한 후 수술 6주의 추시 관찰 초음파 검사상 5예(23%, 소 및 중 파열 1예, 대 및 광범위 파열 4예)에서 재파열 소견을, 능동적 운동을 시행한 후 수술 3개월의 추시 관찰 초음파 검사상 7예(32%, 소 및 중파열 2예, 대 및 광범위 파열 5예)에서 재파열 소견을 보였다. 결론: 회전근 개 파열에 대한 관절경적 치료 후 초음파 연속 검사는 술 후 틈새와 술 후 재파열을 구분하는데 도움을 줄 수 있었으며, 수술 후 6주에 23%, 3개월에 32%의 재파열 소견을 보인 바 재활 치료시 추가 치료의 방침을 세우는데 도움을 줄 수 있을 것으로 생각되었다. Purpose: The findings of preoperative magnetic resonance imaging (MRI) and ultrasonography (US) examination in the diagnosis of rotator cuff tear were then compared with the findings of arthroscopic examination, and to evaluate the postoperative integrity of rotator cuff using serial US examination. Methods: Between February and May 2008, 29 patients with rotator cuff tear had undergone preoperative US and MRI examination and subsequent arthroscopic examination. And the results of MRI and US were compared with intra-operative results of the arthroscopic examination. We observed the postoperative integrity of rotator cuff using serial (postoperative 2 weeks, 6 weeks, 3 months) US examination. Results: The sensitivity of US and MRI for identifying rotator cuff tear were 100% and 100%. The sensitivity of US and MRI were 95% and 82% in full thickness tear, and 50%, 33% in partial thickness tear, respectively. Overall accuracy of US and MRI were 86%, 69%. Among 22 patients were operated for full thickness tear, intra-operative gap formation was identified in 11 patients (50%, small to medium 2 cases, large to massive 9 cases) which were identified at 2 weeks postoperative US. We could find 5 re-tears (23%, small to medium 1 case, large to massive 4 cases) on 6 weeks postoperative US after passive range of motion (ROM) exercise, and could also find 7 re-tears (32%, small to medium 2 cases, large to massive 5 cases)on 3 months postoperative US after active ROM exercise. Conclusion: Serial US after arthroscopic rotator cuff repair was useful to differentiate intra-operative gap formation from postoperative re-tear. We found 5 retears (23%) at 6 weeks and 7 retears (32%) at 3 months postoperative US, it was useful to make treatment plan during postoperative rehabilitation.

Al₂O₃와 TiO₂의 반응소결로 제조한 Al₂TiO₅-기계가공성 세라믹스

박재현,이원재,김일수,Park, Jae-Hyun,Lee, Won-Jae,Kim, Il-Soo 한국세라믹학회 2010 한국세라믹학회지 Vol.47 No.6

Aluminium titanate($Al_2TiO_5$) has extremely anisotropic thermal expansion properties in single crystals, and polycrystalline material spontaneously microcracks in the cooling step after sintering process. These fine intergranular cracks limit the strength of the material, but provide an effective mechanism for absorbing strain energy during thermal shock and preventing catastrophic crack propagation. Furthermore, since machinable BN-ceramics used as an insulating substrate in current micro-electronic industry are very expensive, the development of new low-cost machinable substrate ceramics are consistently required. Therefore, cheap $Al_2TiO_5$-machinable ceramics was studied for the replacement of BN ceramics. $Al_2O_3-Al_2TiO_5$ ceramic composite was fabricated via in-situ reaction sintering. $Al_2O_3$ and $TiO_2$ powders were mixed with various mol-ratio and sintered at 1400 to $1600^{\circ}C$ for 1 h. Density, hardness and strength of sintered ceramics were systematically measured. Phase analysis and microstructures were observed by XRD and SEM, respectively. Machinability of each specimens was tested by micro-hole machining. The results of research showed that the $Al_2TiO_5$-composites could be used for low-cost machinable ceramics.

게임 기획 산출물의 일관성 유지를 위한 변경 추적 기법

박재현,이두원,류성열,Park Jae-Hyun,Yi Du-Won,Rhew Sung-Yul 한국정보처리학회 2006 정보처리학회논문지D Vol.13 No.1

한국게임산업개발원에서 연구 발표한 게임제작 프로세스와 게임 기획서 표준양식은 게임 산업을 위한 중요한 초석이 되었다. 그러나 게임기획은 기획자의 새로운 아이디어와 변경으로 정확한 산출물을 작성할 수 없어 소프트웨어의 품질을 보장할 수 없다. 본 연구에서는 기획단계에서 생성되는 산출물들을 일관성 있게 유지 관리하고 변경된 내용을 추적할 수 있는 체계를 정립하였다. 첫째, 각 산출물간의 연관관계를 표현하늘 ACT그래프, 산출물의 변경을 추적 관리를 위한 ACT 테이블 및 산출물 변경 이력 테이블을 정의하였다. 또 이를 활용한 게임 기획 ACT 프로세스를 제시하였다. 제시한 추적 기법의 유효성을 검증하기 위하여 사례연구를 통해 게임 기획 산출물의 변경 발생시 게임 기획자가 관련 산출물과 항목을 신속히 파악하고 변경 가능한 것을 확인함으로써 게임 기획 산출물의 일관성 유지 노력과 시간을 절약할 수 있음을 보였다. The Game development process that the Korea Game Development Infinity researches and publishes has laid important groundwork for the game industry. However, the game design cannot guarantee a software quality because an artifact is made incorrect by a game planner's new idea and modification. In this paper theorized the system to maintain artifacts consistently that is generated in planning phase and make changed contents traceable. First, it defined an ACT graph to represent relation of between artifacts, a ACT table that traces and manages it changes and a table of artifacts change history. Also, it suggested the ACT process applying as we mentioned above. Then we worked a case study to verify the change tracking technique which is presented. In a case study, we find game designer is capable to grip and modify a change of artifacts when it occurs a change of game design artifacts. As a result of that, we can save the time and effort to maintain the consistency among game design artifacts.