• 제목/요약/키워드: Extreme temperature

검색결과 653건 처리시간 0.034초

화강암의 풍화에 미치는 염분과 산성용액의 영향 (Effects of Salts and Acid Solutions on the Weathering of Granite)

  • 손병현;정종현;김현규;유정근;이형근
    • 대한환경공학회지
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    • 제27권1호
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    • pp.101-108
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    • 2005
  • 대부분의 석조문화재는 외부 환경에 노출되어 있어 외관이 크게 변형되어졌고, 특히 최근의 산업화와 환경오염물질의 영향으로 풍화가 가속화되고 있다. 본 연구에서는 석조문화재의 풍화에 미치는 환경영향을 알아보기 위해 산성용액과 염분용액에 신선한 화강암을 침수한 후 물리 화학적 특성을 조사하였고, 석조문화재 보존 방법의 일환으로 화강암에 $TiO_2$ 광촉매를 코팅한 후 코팅이 화강암의 풍화에 미치는 영향도 조사하였다. 산성용액과 염분용액에 신선한 화강암을 침수시켰을 때 8가지 광물성분(Si, Mg, Ca, Na, K, Fe, Mn, Al)의 용출량은 반응초기에 급격히 증가하였고 암석 표면의 구성광물들은 대부분 신선한 화강암(fresh granite)보다 낮은 농도값을 나타내어 산성용액이나 염분용액에 의한 풍화의 영향 정도를 확인할 수 있었다. 실험 전 후의 화강암의 물리적 특성 분석 결과, 강제 풍화시킨 시료의 밀도는 평균 $2.55-2.56\;g/cm^3$으로 신선한 화강암(평균밀도는 $2.60\;g/cm^3$)에 비해 약간 낮은 값을 보였고 압축강도는 신선한 화강암에 배해 아주 낮았지만 포아송비는 상대적으로 약간 높은 값을 나타내었다. 또한 강제풍화시킨 석재의 흡수율은 $0.481{\sim}0.836%$로서 신선한 화강암에 비해 1.2-2.1배 정도 높게 나타났다. $TiO_2$ 광촉매를 화강암에 코팅한 후 산성용액과 염분용액에 의한 강제풍화시 광물성분의 용출율과 함수율 등이 많이 저감되어 석조문화재의 풍화속도를 완화시키는 것으로 나타나 석조문화재의 표면에 $TiO_2$ 코팅 처리를 하면 석조문화재의 풍화를 예방하는 효과가 있을 것으로 나타났다.

국내 현생 심성암류의 방사성 물질의 농도 및 의미 (Concentration of Radioactive Materials for the Phanerozoic Plutonic Rocks in Korea and Its Implication)

  • 김성원
    • 자원환경지질
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    • 제53권5호
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    • pp.565-583
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    • 2020
  • 최근 생활용품 및 건축자재 등에서 검출된 자연 방사성 물질로 인해 사회적으로 다양한 문제가 발생하고 있으며, 이는 조속히 해결해야 될 사회현안으로 대두되고 있다. 우리나라에서도 토양이나 지하수 내 중금속 및 우라늄, 라돈 등의 자연방사성 물질에 대해서 환경부에 의해 지난 20년 이상 장기간 조사된 바 있고, 토양과 지하수 내 자연방사성 물질의 기원이 암석-성인-변형적 특성 등의 지질학적 요인들과 밀접한 상관관계를 보여주는 것으로 추정되고 있지만, 기반암, 기반암 상부토양 및 지하수가 발달한 단층계 내 자연방사성 물질의 국가배경농도가 수립되어 있지 않아 정확한 지질학적 상관관계 규명이 미흡한 실정이다. 본 연구에서는 국내 현생 심성암류의 성인과 천연 방사성(라돈, 우라늄, 토륨 등)물질 농도와의 상관관계에 대한 예비 연구를 수행하였다. 현생 심성암류 중 알칼리 화강암류(섬장암, 몬조니암, 몬조섬록암 및 알칼리화강암)는 높은 마그마 온도와 고알칼리성의 경향 때문에 U, Th, Zr, REE 및 Nb 등이 부화되는 특징을 보여주어 높은 U과 Th 농도를 가진다. 지각물질의 혼합에 의해 고분화된 화강암류(우백질 화강암, 복운모화강암, 고알루미형질 S-type 화강암 및 페그마타이트)는 고분화되지 않은 일반 화강암류(섬록암, 화강섬록암 및 화강암)보다 U, Th 및 K+Na이 더욱 부화되는 경향을 보여준다. 고알칼리성 화강암류들은 주로 판내부의 열개환경, 대륙충돌 조산작용과 해양판의 대륙판 아래 섭입 이후에 일어나는 확장환경에서 생성된다. 반면에 우리나라에서 주로 산출되는 아알칼리성 캘크알칼리 화강암류는 해양판의 대륙판 밑으로의 섭입에 의한 호환경에서 주로 생성된다. 결과적으로 국내 현생 심성암류의 U, Th 및 K 함량변화는 지구조 환경에 의한 암석성인과 밀접한 연관성을 가지는 것으로 추정되며, 현생화강암류 대한 감마분석 자연방사성 핵종(226Ra, 232Th 및 40K) 예비 결과들은 고알칼리성과 고분화된 화강암류에서 높은 값을 보여준다.

호텔 뷔페음식(飮食)에 관(關)한 실태조사(實態調査) -제(弟) 2보(報). 여성(女性)들의 뷔페식당(食堂)에서의 끽식행동(喫食行動)에 관(關)한 연구(硏究)- (The Present State and Problems of Hotel Buffet Styled Restaurant -II. A Survey of Ecology in Food and Nutrition of Some Urban Females Dining in Hotel Buffet Styled Restaurant-)

  • 최경숙;모수미
    • 한국식생활문화학회지
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    • 제6권2호
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    • pp.185-197
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    • 1991
  • An eating behavior research was done with 50 females at a buffet styled restaurant during their lunch time. Of the respondents, 52.0% were professional and 54.0% were graduate school graduates. Of the respondents, 58.0% of the company were friends and 24.0% were relatives. The average time period of eating was $93.0{\pm}23.4$ minutes. The average frequency of taking food was $4.0{\pm}1.1$ and the average frequency of taking food after satiety was $1.4{\pm}0.8$. It is significant that lower frequency of food consumption was directly proportional to the age groups of respondents. The average selected food items were $30.4{\pm}7.1$ out of 175 and the average weight of the consumed food was $995.0{\pm}240.9$ g. The older age group chose a similar number of food items, but the amount of each food item was considerably less than younger. So the younger the age group was, the more they ate. The average food items at one time was $7.1{\pm}2.2$ and the average food weight time was $233.7{\pm}69.7$ g. The percentage of respondents who evaluated themselves as 'ate too much' was 70.0% and those who evaluate themselves 'ate properly' was 14.0%. Most of them were satisfied with the buffet service. The average of number of food items consumed by respondents before cooking was $50.5{\pm}8.9$. The consumption of calories and nutrients was compared with the Korean Daily Recommended Dietary Allowances. The consumed calories were 60.9% of RDAs, protein 104.4%, calcium 77.1%, iron 129.8%, vitamin A 66.5%, thiamin 96.0%, riboflavin 95.7%, niacin126.6% and ascorbic acid 112.3%. This data exceeded 1/3 of the Korean Daily RDAs tremendously and tells us extreme overeating. The energy ratio of carbohydrate: fat: protein was 51.6: 29.9: 18.5. Caloric consumption of animal food was 27.9% and the consumption rate of the other nutrients from animal food was considerably high. But the consumption rate of vitamin A was 90.9% from vegetable groups. Accoding to this study, buffet service gives some advantages. It gives customers an good opportunity to vary their food intake, which enhances eating experiences and can cause an improvemont of food habits. But overeating is a problem. Therefore, we think it is necessary for those women who have influence over their family's food selection, to have nutrition education about a desirable order of eating a meal, food selection, and health problems due to overeating at buffet styled restaurant. There should be some improvement in the management of buffet service. For example, proper temperature, texture, and freshness of the food should be maintained. Prevention of mixed food smells should be considered as well. To lower the price it is desirable to reduce the number of similar items and to use seasonal food as much as possible. A buffet styled restaurant with less food items with cheaper prices is recommended. Various traditional food should be developed for the menu items. We expect buffet services to be sutable to maintain good health and to be popular to any eater.

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Beak Trimming Methods - Review -

  • Glatz, P.C.
    • Asian-Australasian Journal of Animal Sciences
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    • 제13권11호
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    • pp.1619-1637
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    • 2000
  • A review was undertaken to obtain information on the range of beak-trimming methods available or under development. Beak-trimming of commercial layer replacement pullets is a common yet critical management tool that can affect the performance for the life of the flock. The most obvious advantage of beak-trimming is a reduction in cannibalism although the extent of the reduction in cannibalism depends on the strain, season, and type of housing, flock health and other factors. Beak-trimming also improves feed conversion by reducing food wastage. A further advantage of beak-trimming is a reduction in the chronic stress associated with dominance interactions in the flock. Beak-trimming of birds at 7-10 days is favoured by Industry but research over last 10 years has shown that beak-trimming at day-old causes the least stress on birds and efforts are needed to encourage Industry to adopt the practice of beak-trimming birds at day-old. Proper beak-trimming can result in greatly improved layer performance but improper beak-trimming can ruin an other wise good flock of hens. Re-trimming is practiced in most flocks, although there are some flocks that only need one trimming. Given the continuing welfare scrutiny of using a hot blade to cut the beak, attempts have been made to develop more welfare friendly methods of beak-trimming. Despite the developments in design of hot blade beak-trimmers the process has remained largely unchanged. That is, a red-hot blade cuts and cauterises the beak. The variables in the process are blade temperature, cauterisation time, operator ability, severity of trimming, age of trimming, strain of bird and beak length. This method of beak-trimming is still overwhelmingly favoured in Industry and there appears to be no other alternative procedures that are more effective. Sharp secateurs have been used trim the upper beak of both layers and turkeys. Bleeding from the upper mandible ceases shortly after the operation, and despite the regrowth of the beak a reduction of cannibalism has been reported. Very few differences have been noted between behaviour and production of the hot blade and cold blade cut chickens. This method has not been used on a large scale in Industry. There are anecdotal reports of cannibalism outbreaks in birds with regrown beaks. A robotic beak-trimming machine was developed in France, which permitted simultaneous, automated beak-trimming and vaccination of day-old chicks of up to 4,500 chickens per hour. Use of the machine was not successful because if the chicks were not loaded correctly they could drop off the line, receive excessive beak-trimming or very light trimming. Robotic beak-trimming was not effective if there was a variation in the weight or size of chickens. Capsaicin can cause degeneration of sensory nerves in mammals and decreases the rate of beak regrowth by its action on the sensory nerves. Capsaicin is a cheap, non-toxic substance that can be readily applied at the time of less severe beak-trimming. It suffers the disadvantage of causing an extreme burning sensation in operators who come in contact with the substance during its application to the bird. Methods of applying the substance to minimise the risk to operators of coming in contact with capsaicin need to be explored. A method was reported which cuts the beaks with a laser beam in day-old chickens. No details were provided on the type of laser used, or the severity of beak-trimming, but by 16 weeks the beaks of laser trimmed birds resembled the untrimmed beaks, but without the bill tip. Feather pecking and cannibalism during the laying period were highest among the laser trimmed hens. Currently laser machines are available that are transportable and research to investigate the effectiveness of beak-trimming using ablasive and coagulative lasers used in human medicine should be explored. Liquid nitrogen was used to declaw emu toes but was not effective. There was regrowth of the claws and the time and cost involved in the procedure limit the potential of using this process to beak-trim birds.

Determination of optimum gamma ray range for radiation mutagenesis and hormesis in quinoa (Chenopodium quinoa Willd.)

  • Park, Chan Young;Song, Seon Hwa;Sin, Jong Mu;Lee, Hyeon Young;Kim, Jin Baek;Shim, Sang In
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.240-240
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    • 2017
  • Quinoa (Chenopodium quinoa Willd.) is one of the ancient crops cultivated in the Andes region at an altitude of 3,500-4000m in Chile and Bolivia from 5000 BC. It contains a large amount of protein, minerals and vitamins in comparison with other crops. The cultivation area has been increasing worldwide because of its excellent resistance to various abiotic stress such as salinity, drought and low temperature. ${\gamma}$-Ray radiation of high dose is often used as a tool to induce mutations in plant breeding, but it has a deleterious effect on organisms. However, the radiation may have a positive stimulatory effect of 'hormesis' in the low dose range. This experiment was carried out to investigate the optimum dose range for creating the quinoa genetic resources and to investigate the hormesis effect at low dose on the quinoa. This experiment was performed for 120 days from November, 2016 to February, 2017 in the greenhouse of Gyeongsang National University. ${\gamma}$-Ray radiation was irradiated to seeds at 0 Gy, 50 Gy, 100 Gy, 200 Gy, 300 Gy, 400 Gy, 600 Gy, 800 Gy and 1000 Gy for 8 hours. (50 Gy) using the low level radiation facility ($Co^{60}$) of Cooperative Research Institute of Radiation Research Institute, KAERI. Fifty seeds were placed on each petri dish lined with wet filter paper and germination rate was measured at a time interval of 2 hours for 40 hrs. The length of the root length was measured one week after germination. Each treatment was carried out in 3 replicates. The growth of seedlings were investigated for 10 days after transplanting of 30 day-old seedlings. The plant height, NDVI, SPAD, Fv/Fm, and panicle weight were measured. The germination rate was highest at 50Gy and 0Gy and the rate of seeds treated with 400Gy or higher rate decreased to 25% of the seeds treated with 50Gy. The emergence rate of seedling in pot experiment was higher at the dose of 200 Gy, 300 Gy and 400 Gy than at 0 and 50Gy. However, the rate was lower at strong radiation higher than 600Gy at which $1^{st}$ leaf was not expanded fully and dead due to extreme overgrowth at 44 days after treatment (DAT). The highest value of panicle weight was observed at 50Gy (6.15g) and 100Gy (5.57g). On the other hand, the weight at high irradiated dose of 300Gy and 400Gy was decreased by about 55% compared to low dose (50 Gy). NDVI measurement also showed the highest value at 50 Gy as the growth progressed. SPAD was the highest at 400 Gy and showed positive correlation with irradiation dose except 0 Gy. Fv/Fm was high at 50 Gy up to 30 DAT and no difference between treatments was observed except for 400 Gy from 44 DAT. The plant height was the highest in 50Gy during the growing period and was higher in the order of 50Dy, 100Gy, 0Gy, 200Gy, 300Gy and 400Gy in 88 DAT. In this experiment, the optimal radiation dose for hormesis was 50Gy and 100Gy, and the optimal radiation dose for mutagenesis seems to be 400 Gy.

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굴곡성 기관지경을 통한 겸자 생검술과 냉동 생검술의 비교 (Comparison of Forcep-biopsy and Cryo-biopsy by a Flexible Bronchoscopy)

  • 김재현;최정민;송성은;이은미;이송주;옥철호;장태원;정만홍;장희경
    • Tuberculosis and Respiratory Diseases
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    • 제66권2호
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    • pp.110-115
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    • 2009
  • 연구배경: 냉동 생검은 극저온으로 암 조직을 얼려 조직의 괴사를 만들어 검체를 채취할 수 있는데 출혈이 적어서 많은 양의 조직을 한번에 채취할 수 있다는 장점이 있다. 본 연구에서는 기관지 내 병소가 있는 폐암 환자에서 굴곡형 기관지 내시경을 이용하여 겸자 생검과 냉동 생검을 시행하여 얻은 각각의 조직의 특징을 비교하였고 냉동 생검을 시행하여 얻은 조직을 통해 항암제 감수성 검사를 위한 배양 결과 및 혈관 내피 세포 성장인자(vascular endothelial growth factor, VEGF)의 발현 여부를 연구하였다. 방 법: 고신대학교 복음병원에서 폐암으로 진단되어 시행한 기관지경에서 용종성 병병이거나 결절형 돌출성 병변이 관찰된 환자 30명을 대상으로 하였다. 냉동 생검은 기관지경을 병소에 삽입한 후 먼저 겸자 생검을 시행하였고, 이후 겸자 채널을 통해 냉동 탐침을 삽입하여 병소에 접촉시켰다. $-80^{\circ}C$로 8초간 급속 냉동한 후 조직을 떼내어 내시경과 함께 빼낸 뒤 채취하였다. 결 과: 겸자 생검 조직과 냉동 생검 조직의 평균 크기는 각각 2.0${\pm}$1.2 mm, 6.0${\pm}$3.0 mm였다. 조직의 정확한 진단이 된 경우는 겸자 생검 조직에서 23예(76%), 냉동 생검 조직에서 27예(90%)였다. 겸자 생검에서 확진이 되지 않았던 7예 중 5예에서 진단이 가능하였다. 조직의 분화도 결정은 겸자 생검 조직과 냉동 생검 조직에서 각각 15예, 25예에서 가능하였다. 냉동 생검을 통해 얻은 조직은 총 5예에서 항암제 감수성 검사를 의뢰하였고 전 예에서 배양이 이루어져 적절한 감수성 검사를 시행할 수 있었다. 또한 냉동 생검을 통해 얻은 조직 중 2예에서 VEGF의 발현 정도를 관찰하고 판정할 수 있었다. 결 론: 굴곡형 기관지 내시경을 이용한 냉동 조직 생검은 기존의 겸자 생검에 비해 비교적 큰 조직을 얻을 수 있는 안전하고 유용한 방법이 될 수 있을 것이며 또한 항암제 감수성 검사를 위한 검체 확보 및 VEGF의 발현 정도를 관찰하고 판정하는 데에도 도움이 될 것으로 생각된다.

중심성 기도 폐쇄를 동반한 폐암에서 냉동치료의 임상적 유용성 및 부작용 (Clinical Benefits and Complications of Cryotherapy in Advanced Lung Cancer with Central Airway Obstruction)

  • 정진용;이승룡;김대현;이경주;이은주;강은해;정기환;김제형;신철;심재정;인광호;강경호;유세화
    • Tuberculosis and Respiratory Diseases
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    • 제64권4호
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    • pp.272-277
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    • 2008
  • 연구배경: 중심성 기도폐쇄를 동반하는 진행성 폐암환자에서 기도폐쇄를 호전시키기 위해 다양한 중재적 시술 Tuberculosis and Respiratory Diseases Vol. 64. No. 4, Apr. 2008277방법들이 시도되고 있으며, 이러한 시술방법 중 최근 굴절성 cryoprobe를 이용한 냉동치료가 국내에서도 시도되고 있다. 방법: 냉동치료 기계는 cryomachine과 cryoprobe로 구성되며, 냉매로는 아산화질소(N2O)를 사용하였다. 굴곡경 기관지내시경의 working chanel을 통해 굴절성 cryoprobe를 악성종양의 중심에 위치한 후 급속 냉동($-89^{\circ}C$)하여 악성 종양 조직을 냉동 시킨 후 stalk을 puling하여 제거하거나 급속 냉동과 해동 과정을 반복하였다. 결과: 중심성 기도폐쇄가 발생한 진행성 폐암 환자 4명에게 냉동치료를 시술하였다. 3명의 환자에서 성공적으로 기도폐쇄를 유발하는 종양을 제거하였으며, 그 후 호흡곤란 및 무기폐 소견이 호전되었다. 1명의 환자에서 기관지 천공으로 인한 종격동 기종이 발생하였으며 또 다른 환자에서 냉동치료 도중 대량 출혈이 발생하였으나 응급 조치 후 다시 회복되었다.

탄소계 경질 박막의 연구 및 산업 적용 동향 (Trend in Research and Application of Hard Carbon-based Thin Films)

  • 이경황;박종원;양지훈;정재인
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2009년도 춘계학술대회 논문집
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    • pp.111-112
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    • 2009
  • Diamond-like carbon (DLC) is a convenient term to indicate the compositions of the various forms of amorphous carbon (a-C), tetrahedral amorphous carbon (ta-C), hydrogenated amorphous carbon and tetrahedral amorphous carbon (a-C:H and ta-C:H). The a-C film with disordered graphitic ordering, such as soot, chars, glassy carbon, and evaporated a-C, is shown in the lower left hand corner. If the fraction of sp3 bonding reaches a high degree, such an a-C is denoted as tetrahedral amorphous carbon (ta-C), in order to distinguish it from sp2 a-C [2]. Two hydrocarbon polymers, that is, polyethylene (CH2)n and polyacetylene (CH)n, define the limits of the triangle in the right hand corner beyond which interconnecting C-C networks do not form, and only strait-chain molecules are formed. The DLC films, i.e. a-C, ta-C, a-C:H and ta-C:H, have some extreme properties similar to diamond, such as hardness, elastic modulus and chemical inertness. These films are great advantages for many applications. One of the most important applications of the carbon-based films is the coating for magnetic hard disk recording. The second successful application is wear protective and antireflective films for IR windows. The third application is wear protection of bearings and sliding friction parts. The fourth is precision gages for the automotive industry. Recently, exciting ongoing study [1] tries to deposit a carbon-based protective film on engine parts (e.g. engine cylinders and pistons) taking into account not only low friction and wear, but also self lubricating properties. Reduction of the oil consumption is expected. Currently, for an additional application field, the carbon-based films are extensively studied as excellent candidates for biocompatible films on biomedical implants. The carbon-based films consist of carbon, hydrogen and nitrogen, which are biologically harmless as well as the main elements of human body. Some in vitro and limited in vivo studies on the biological effects of carbon-based films have been studied [$2{\sim}5$].The carbon-based films have great potentials in many fields. However, a few technological issues for carbon-based film are still needed to be studied to improve the applicability. Aisenberg and Chabot [3] firstly prepared an amorphous carbon film on substrates remained at room temperature using a beam of carbon ions produced using argon plasma. Spencer et al. [4] had subsequently developed this field. Many deposition techniques for DLC films have been developed to increase the fraction of sp3 bonding in the films. The a-C films have been prepared by a variety of deposition methods such as ion plating, DC or RF sputtering, RF or DC plasma enhanced chemical vapor deposition (PECVD), electron cyclotron resonance chemical vapor deposition (ECR-CVD), ion implantation, ablation, pulsed laser deposition and cathodic arc deposition, from a variety of carbon target or gaseous sources materials [5]. Sputtering is the most common deposition method for a-C film. Deposited films by these plasma methods, such as plasma enhanced chemical vapor deposition (PECVD) [6], are ranged into the interior of the triangle. Application fields of DLC films investigated from papers. Many papers purposed to apply for tribology due to the carbon-based films of low friction and wear resistance. Figure 1 shows the percentage of DLC research interest for application field. The biggest portion is tribology field. It is occupied 57%. Second, biomedical field hold 14%. Nowadays, biomedical field is took notice in many countries and significantly increased the research papers. DLC films actually applied to many industries in 2005 as shown figure 2. The most applied fields are mold and machinery industries. It took over 50%. The automobile industry is more and more increase application parts. In the near future, automobile industry is expected a big market for DLC coating. Figure 1 Research interests of carbon-based filmsFigure 2 Demand ratio of DLC coating for industry in 2005. In this presentation, I will introduce a trend of carbon-based coating research and applications.

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이상기후에 의한 재배시설의 취약성 평가 (Vulnerability Assessment of Cultivation Facility by Abnormal Weather of Climate Change)

  • 윤성탁;이용호;홍선희;김명현;강기경;나영은;오영주
    • 한국농림기상학회지
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    • 제15권4호
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    • pp.264-272
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    • 2013
  • 기후변화는 기온의 상승과 강수량의 변화뿐만 아니라 이상기후 발생과 강도 증가의 원인이 되고 있다. 최근의 농업 재배시설의 피해는 기후변화에 의한 강우강도의 증가와 폭설 등에 의해 증가하고 있다. 이와 같이 기후변화에 취약한 부분에 대한 평가와 국가차원의 적응정책이 중요한 시점에 와 있다. 본 연구는 232개 시군구를 대상으로 재배시설의 취약성 평가를 실시하였고 취약성 평가의 기간은 현재는 2000년, 미래는 A1B 시나리오를 기준으로 2020년, 2050년, 2100년에 대한 자료를 취합하였다. 취약성 평가 결과 기후노출과 민감도, 적응능력 모두에 크게 영향을 주었고 취약성 지수가 가장 높은 지역들은 기후노출과 민감도가 높은 지역들이었다. 기후노출은 전라도와 강원도에서 높게 나타났으며 민감도는 대규모 시설재배 단지가 형성된 지역들에서 높게 나타났다. 또한 적응능력은 도 수준에서 차이가 나타났는데 적응능력이 상대적으로 높은 전라남도와 경상북도는 취약성이 상쇄되어 낮은 취약성 지수가 나타났다. SRES A1B 시나리오에 의한 미래 예측결과 우리나라 전반적으로 취약성이 상승했으며 그 상승폭은 2000년대부터 2020년사이에 급격하게 나타났다. 또한 취약성의 향상은 우리나라 전국에 걸쳐 높아졌으며 이는 우리나라의 재배 시설 피해를 주는 기상재해의 위험이 전국적으로 증가할 것을 나타내는 것으로 판단되었다. 본 조사를 통하여 전국 시군구의 이상기후에 대한 재배시설의 취약성을 평가하는 방법으로서 CCGIS를 제시하였으며 그 결과 전국의 기상재해에 대한 기후노출, 민감도, 적응능력들의 분포를 파악할 수 있었다. 또한 취약성 지수가 높은 주요 시군구를 중심으로 주성분 분석의 결과 지역의 취약한 요소들을 판단할 수 있었다. 이는 각 지역별로 이상기후에 대한 재배시설의 대책 마련에 기초자료로 사용할 수 있을 것으로 판단된다. 또한 본 조사는 선행연구, 전문가를 활용한 델파이조사 등 합리적인 방법을 통하여 이루어졌으나 신뢰성의 향상을 위해서는 재배시설의 피해와 관련된 더욱 상세하고 연관성 있는 자료가 확보되어야 할 것으로 판단되었다.

A Laboratory-Scale Study of the Applicability of a Halophilic Sediment Bioelectrochemical System for in situ Reclamation of Water and Sediment in Brackish Aquaculture Ponds: Effects of Operational Conditions on Performance

  • Pham, Hai The;Vu, Phuong Ha;Nguyen, Thuy Thu Thi;Bui, Ha Viet Thi;Tran, Huyen Thanh Thi;Tran, Hanh My;Nguyen, Huy Quang;Kim, Byung Hong
    • Journal of Microbiology and Biotechnology
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    • 제29권10호
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    • pp.1607-1623
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    • 2019
  • Sediment bioelectrochemical systems (SBESs) can be integrated into brackish aquaculture ponds for in-situ bioremediation of the pond water and sediment. Such an in-situ system offers advantages including reduced treatment cost, reusability and simple handling. In order to realize such an application potential of the SBES, in this laboratory-scale study we investigated the effect of several controllable and uncontrollable operational factors on the in-situ bioremediation performance of a tank model of a brackish aquaculture pond, into which a SBES was integrated, in comparison with a natural degradation control model. The performance was evaluated in terms of electricity generation by the SBES, Chemical oxygen demand (COD) removal and nitrogen removal of both the tank water and the tank sediment. Real-life conditions of the operational parameters were also experimented to understand the most close-to-practice responses of the system to their changes. Predictable effects of controllable parameters including external resistance and electrode spacing, similar to those reported previously for the BESs, were shown by the results but exceptions were observed. Accordingly, while increasing the electrode spacing reduced the current densities but generally improved COD and nitrogen removal, increasing the external resistance could result in decreased COD removal but also increased nitrogen removal and decreased current densities. However, maximum electricity generation and COD removal efficiency difference of the SBES (versus the control) could be reached with an external resistance of $100{\Omega}$, not with the lowest one of $10{\Omega}$. The effects of uncontrollable parameters such as ambient temperature, salinity and pH of the pond (tank) water were rather unpredictable. Temperatures higher than $35^{\circ}C$ seemed to have more accelaration effect on natural degradation than on bioelectrochemical processes. Changing salinity seriously changed the electricity generation but did not clearly affect the bioremediation performance of the SBES, although at 2.5% salinity the SBES displayed a significantly more efficient removal of nitrogen in the water, compared to the control. Variation of pH to practically extreme levels (5.5 and 8.8) led to increased electricity generations but poorer performances of the SBES (vs. the control) in removing COD and nitrogen. Altogether, the results suggest some distinct responses of the SBES under brackish conditions and imply that COD removal and nitrogen removal in the system are not completely linked to bioelectrochemical processes but electrochemically enriched bacteria can still perform non-bioelectrochemical COD and nitrogen removals more efficiently than natural ones. The results confirm the application potential of the SBES in brackish aquaculture bioremediation and help propose efficient practices to warrant the success of such application in real-life scenarios.