• 한국구조물진단유지관리공학회 논문집
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• 제16권6호
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• pp.155-162
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• 2012

해수에 노출된 콘크리트 구조물은 시간의 경과에 따라 철근부식이 야기될 수 있으며, 이는 구조적인 성능저하로 진전된다. 1단계 연구에서 도출된 해수전착시스템의 개발을 통하여 2단계 연구에서는 해수전착 코팅된 철근 및 코팅철근을 사용한 RC 콘크리트 부재의 구조적, 내구적 성능이 평가되었다. 내구적 성능평가에서는 반전위 측정이 수행되었는데, 코팅된 철근은 일반철근의 35%수준의 부식속도를 가지고 있었으므로 높은 내부식성을 확보하고 있었다. 구조실험에서는 직접인장시험, 부착력시험, RC 부재를 이용한 휨 및 전단시험이 수행되었다. 인장강도 시험에서는 3.2%, 부착성능에서는 8.8%의 강도 증가가 코팅된 철근에서 평가되었다. RC보에 대한 실험에서는 최대하중 및 파괴형태는 두가지 경우에서 거의 동일하게 평가되었다. 해수전착된 시편은 철근주위에 콘크리트와 비슷한 화합물(수산화마그네슘, 탄산칼슘)이 형성되므로 부착력 및 강도를 일부 증가시키는 것으로 평가되었다. 해수전착철근은 피로, 내충격성, 장기침지실험 등을 통하여 성능이 입증되면 더욱 활발하게 사용될 것으로 사료된다.

• 한국수산과학회지
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• 제43권2호
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• pp.146-158
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• 2010

In order to evaluate the characteristics of sediments and pollution by organic matter and metallic elements in intertidal sediments along the southwestern coast of Korea, we measured various geochemical parameters, including the mean grain size (Mz), water content (WC), ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and metallic elements (Al, Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, As), in intertidal surface sediments. The Mz of the surface sediments ranged from 2.1 to 8.3$\phi$, indicating that the surface sediments consist of various sedimentary facies, such as sand, slightly gravelly mud, sandy mud, and silt. The IL and COD in surface sediment ranged from 0.8 to 5.5% (mean $2.9\pm1.2%$) and from 3.9 to $13.8\;mgO_2/g{\cdot}dry$ (mean $8.5\pm2.6\;mgO_2/g{\cdot}dry$), respectively, which were lower than the values for surface sediment in areas near fish and shellfish farms or industrial complexes. No AVS was detected at any sampling station, despite various sedimentary facies. Most of metallic elements in surface sediments showed relatively good positive correlations with Mz and IL, which imply that the concentrations of metallic elements are mainly controlled by grain size and the organic matter content. The concentrations of metallic elements, except As, at some stations were considerably lower than those in the Sediment Quality Guideline (Effect Range Low, ERL) proposed by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Similarly, the geoaccumulation index (Igeo) class indicated that pollution by metallic elements in intertidal surface sediment, except As, was moderate or non-existent. Our results imply that the intertidal surface sediments along the southwestern coast of Korea are not polluted by organic matter and metallic elements and are healthy for benthic organisms.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.615-630
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• 2002

Various long-term studies have shown that titanium implants as abutments for different types of prostheses have become a predictable adjunct in the treatment of partially or fully edentulous patients. The continuous exposure of dental implants to the oral cavity with all its possible contaminants creates a problem. A lack of attachment, together with or caused by bacterial insult, may lead to peri-implantitis and eventual implant failure. Removal of plaque and calculus deposits from dental titanium implants with procedures and instruments originally made for cleaning natural teeth or roots may cause major alterations of the delicate titanium oxide layer. Therefore, the ultimate goal of a cleaning procedure should be to remove the contaminants and restore the elemental composition of the surface oxide without changing the surface topography and harming the surrounding tissues. Among many chemical and mechanical procedure, air-powder abrasive have been known to be most effective for cleaning and detoxification of implant surface. Most of published studies show that the dental laser may be useful in the treatment of pen-implantitis. $CO_2$ laser and Soft Diode laser were reported to kill bacteria of implant surface. The purpose of this study was to obtain clinical guide by application these laser to implant surface by means of Non-contact Surface profilometer and X-ray photoelectron spectroscopy(XPS) with respect to surface roughness and atomic composition. Experimental rough pure titanium cylinder models were fabricated. All of them was air-powder abraded for 1 minute and they were named control group. And then, the $CO_2$ laser treatment under dry, hydrogen peroxide and wet condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of the control models. The results were as follows: 1. Mean Surface roughness(Ra) of all experimental group was decreased than that of control group. But it wasn't statistically significant. 2. XPS analysis showed that in the all experimental group, titanium level were decreased, when compared with control group. 3. XPS analysis showed that the level of oxygen in the experimental group 1, 3($CO_2$ laser treatment under dry and wet condition) and 4(Soft Diode laser was used under toluidine blue O solution) were decreased, when compared with control group. 4. XPS analysis showed that the atomic composition of experimental group 2($CO_2$ laser treatment under hydrogen peroxide) was to be closest to that of control group than the other experimental group. From the result of this study, this may be concluded. Following air-powder abrasive treatment, the $CO_2$ laser in safe d-pulse mode and the Soft Diode laser used with photosensitizer would not change rough titanium surface roughness. Especially, $CO_2$ laser treatment under hydrogen peroxide gave the best results from elemental points of view, and can be used safely to treat peri-implantitis.

• 자원환경지질
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• 제36권5호
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• pp.365-374
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• 2003

다양한 유해성 화학물질들이 콘크리트의 설치환경에 따라 외부로부터 유입될 수 있다. 해수에 의한 콘크리트의 성능저하 현상은 해수의 다양한 화학성분에 의한 복잡한 작용이 연관되어 있다. 따라서, 본 연구에서는 주요 해수 성분의 영향으로 인한 콘크리트 성능저하에 관련된 이차광물의 형성에 따른 광물학적, 미세 구조적 변화 특성에 대하여 연구하였다. 부산경남의 해안지역의 기존 콘크리트 구조물들에서 성능저하특징을 관찰하고 콘크리트 시료를 채취하였다. 채취된 시료에 대한 암석학적분석과 XRD 및 SEM/EDAX 분석을 실시하여 골재와 시멘트페이스트의 화학적, 광물학적, 미세구조적 변화를 해석하였다. NaCl, CaCl, $MgCl_2$ 및 $Na_2SO_4$용액을 사용한 실내 콘크리트 변질 실험을 실시하였다. 변질실험 결과를 기존 콘크리트 시료에 대한 분석 결과를 비교함으로서 해수의 주성분들이 콘크리트의 성능저하에의 영향과 메커니즘을 분석하였다. 해수의 알칼리성분들은 알칼리-골재 반응을 가속화하며, 콘크리트의 심한 팽창과 균열을 발생하는 알칼리-칼슘-실리카겔을 형성하는 것으로 나타났다. 탄산화작용은 다량의 비교결성의 방해석을 형성하여 시멘트페이스트를 약화시키고 있다. 또한, 탄산화작용은 그 진행 정도에 따라 일부 이차광물들의 성분과 안정도에 현저한 영향을 미치는 것으로 나타났다. 탄산화가 현저히 진행된 콘크리트에는 다량의 석고가 형성되었으나, 탄산화가 약하게 진행된 것에는 사우마사이트가 에트린자이트와 고용체를 형성하여 미세 균열을 발생하고 있다. 실험적으로, 에트린자이트는 염소의 유입으로 인하여 trichloroaluminate로 전이되거나 분해되는 것으로 나타났다. 해수의 Mg 이온은 비교결성의 브루사이트와 MSH (magnesium silicate hydrate)를 형성하여 시멘트 페이스트의 성능저하의 원인이 되는 것으로 나타났다.

• 한국환경농학회지
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• 제3권2호
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• pp.9-15
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• 1984

제제형태(製劑形態)에 따른 carbofuran의 수중용출속도와 토양중 잔류소장(殘留消長)을 조사하기 위하여 재결정 하여 정제한 carbofuran 원제와 시판(市販) sand-coated granule 및 실험실에서 립상(粒狀)규조토를 담체(擔體)로 제조한 impregnated granule을 공시(供試)하여 시험한 결과는 다음과 같다. 1) Carbofuran의 수중용출속도는 원제impregnated granule> sand-coated granule 순(順)이었으며 3-hydroxy carbofuran과 3-keto carbofuran의 잔류기간도 입제 처리가 원제 처리시 보다 더 길었다. 또한 토양별로 보면 담수 사양토가 비담수 양토에서 보다 carbofuran과 그의 두 대사산물인 3-hydroxy carbofuran과 3-keto carbofuran의 잔류기간이 짧았는데 이는 담수 여부가 토양 중 carbofuran의 분해에 주요한 인자임이 증명되었다. 3) 두 종류의 carbofuran 입제 처리시 3-hydroxycarbofuran과 3-keto carbofuran이 최고 농도에 이르는 기간은 각각 $40{\sim}80$일, $20{\sim}40$일 소요되었으며 입제의 종류별로 보면 impregnated granule 처리가 sandcoated granule 처리보다 3-hydroxy carbofuran과 3-keto carbofuran의 잔류기간이 짧았다.

• 한국환경농학회지
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• 제35권4호
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• pp.247-255
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• 2016

BACKGROUND: Acrylamide (CAS No. 79-06-1) is known to be a carcinogenic compound, and is classified as a Group 2A compound by the International Agency for Research on Cancer (IARC, 1994). Acrylamide can be generated during the browning process via the non-enzymatic Maillard reaction of carbohydrates such as reducing sugars and of amino acids such as asparagine, both of which occur at a temperature above $120^{\circ}C$. Potato tubers contain reducing sugars, and thus, this will affect the safety of processed potato products such as potato chips and French fries. In order to reduce the level of acrylamide in potato processed products, it is therefore necessary to understand factors that affect the reducing sugar content of potatoes, such as environmental factors and potato storage conditions, as well as understanding factors affecting acrylamide formation during potato processing itself. METHODS AND RESULTS: Potatoes were cultivated in eight regions of Korea; For each of these different environments, soil physico-chemical characteristics such as pH, electrical conductivity, total nitrogen, available phosphate, and exchangeable cation content were measured and correlations with potato reducing sugar content and potato chip acrylamide levels were examined. The reducing sugar content in potato during storage for three months was determined and acrylamide level in potato chip was analyzed after processing. The storage temperature levels were $4^{\circ}C$, $8^{\circ}C$, or $10^{\circ}C$, respectively. The acrylamide content of chips prepared from potatoes stored at $10^{\circ}C$ or $20^{\circ}C$ for one month was analyzed and the different frying times were 2, 3, 5, and 7 min. CONCLUSION: This study showed that monitoring and controlling the phosphate content within a potato field should be sufficient to avoid producing brown or black potato chips. For potatoes stored at low temperatures, a reconditioning period ($20^{\circ}C$ for 20 days) is required in order to reduce the levels of reducing sugars in the potato and subsequently reduce the acrylamide and improve chip coloration and appearance.

• 한국미생물·생명공학회지
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• 제14권3호
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• pp.225-232
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• 1986

보리고추장 양조시 고추씨 및 마늘을 첨가하여 제조한 고추장의 숙성과정중의 효소활성도와 이화학적 변화 및 관능검사를 조사하였다. 고추장숙성 중 효소의 활성은 전분액화·당화효소, 중성 protease, lipase모두 증가되었고 전분액화효소를 제외하고는 숙성후기에도 효소의 잔존활성이 높았으며, 고추씨의 첨가도 효소 활성유지에 효과적이었다. pH와 적정산도는 고추씨의 첨가로 변화가 적었고, 마늘의 첨가도 숙성후기에는 큰 차이가 없었다. 총질소, 아미노태질소, 총당, 환원당은 고추씨나 마늘의 첨가로 증가되었으며, 암모니아태질소는 이들의 첨가로 숙성중기에 증가하나 숙성후기에는 큰 차이가 없었다. 알코올의 생성은 고추씨나 마늘의 첨가로 적었으며, 조지방은 고추씨의 첨가로 증가하였다. 10주 숙성 고추장의 맛, 향기 및 색은 전반적으로 마늘첨가구가 무첨가구에 비하여 우수하였다. 따라서 통고추를 이용한 보리고추장은 원료에 2％의 마늘을 첨가하므로써 품질을 개선할 수 있다.

• Asian Journal of Atmospheric Environment
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• 제7권4호
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• pp.177-190
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• 2013

Air pollution trends in Japan between 1970 and 2012 were analyzed, and the impact of air pollution countermeasures was evaluated. Concentrations of CO decreased from 1970 to 2012, and in 2012, the Japanese environmental quality standard (EQS) for CO was satisfied. Concentrations of $SO_2$ dropped markedly in the 1970s, owing to use of desulfurization technologies and low-sulfur heavy oil. Major reductions in the sulfur content of diesel fuel in the 1990s resulted in further decreases of $SO_2$ levels. In 2012, the EQS for $SO_2$ was satisfied at most air quality monitoring stations. Concentrations of $NO_2$ decreased from 1970 to 1985, but increased from 1985 to 1995. After 1995, $NO_2$ concentrations decreased, especially after 2006. In 2012, the EQS for $NO_2$ was satisfied at most air quality monitoring stations, except those alongside roads. The annual mean for the daily maximum concentrations of photochemical oxidants (OX) increased from 1980 to 2010, but after 2006, the $98^{th}$ percentile values of the OX concentrations decreased. In 2012, the EQS for OX was not satisfied at most air quality monitoring stations. Non-methane hydrocarbon (NMHC) concentrations generally decreased from 1976 to 2012. In 2011, NMHC concentrations near roads and in the general environment were nearly the same. The concentration of suspended particulate matter (SPM) generally decreased. In 2011, the EQS for SPM was satisfied at 69.2% of ambient air monitoring stations, and 72.9% of roadside air-monitoring stations. Impacts from mineral dust from continental Asia were especially pronounced in the western part of Japan in spring, and year-round variation was large. The concentration of $PM_{2.5}$ generally decreased, but the EQS for $PM_{2.5}$ is still not satisfied. The air pollution trends were closely synchronized with promulgation of regulations designed to limit pollutant emissions. Trans-boundary OX and $PM_{2.5}$ has become a big issue which contains global warming chemical species such as ozone and black carbon (so called SLCP: Short Lived Climate Pollutants). Cobeneficial reduction approach for these pollutants will be important to improve both in regional and global atmospheric environmental conditions.

• 한국환경과학회지
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• 제26권1호
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• pp.47-54
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• 2017

We analyzed the variation in occurrence time and intensity of attacks by the rice stem borer (Chilo suppressalis Walker) on several crops. This study aimed to understand how C. suppressalis damages crops and to utilize this basic data for the establishment of environment-friendly control methods like pheromone traps. This study surveyed the changes in occurrence patterns of C. suppressalis, biological characteristics of overwintering larvae, and the efficacy of different types of pheromone traps the years. We found similar occurrence patterns of C. suppressalis in different crops. In addition, occurrence time of the first generation was advanced. Overwintering larvae showed no difference in pupal period and weight compared to the non-overwintering ones. However, the larval period was reduced to 19.1 days in Miscanthus field, in contrast to that in the paddy fields. It was confirmed that larvae of C. suppressalis generally prefer the lower part of the stems of Miscanthus. Efficiency of the emergence trap was confirmed to be greater than that of the delta trap for capturing C. suppressalis adults. However, it is necessary to adjust the control period because of the advancement in occurring time of C. suppressalis in recent years. The larvae of C. suppressalis experience favorable environmental conditions for overwintering in Miscanthus fields. The major Miscanthus fields are generally located in the areas protected for sources of drinking water, owing to which spraying of chemical pesticides is very limited. The results of this study provide important inputs for the development of environment-friendly control methods.

• 보존과학회지
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• 제33권4호
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• pp.255-266
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• 2017

국내 문화재 생물피해 방제는 농약에서 유래한 화학적 약제를 사용하여 왔다. 그러나 인체와 환경에 대한 유해성 문제로 인하여 사용이 점차 제한되고 있으며, 새로운 방제약제의 탐색과 안전성 연구에 대한 관심이 지속적으로 증가되고 있다. 개발된 천연 생물방제제의 안전성은 동물실험을 통한 독성평가로 확인하고 있으며, 치사량과 자극성 평가를 위하여 경구독성, 경피독성, 안점막자극 및 피부자극 시험법을 이용하여 안전성을 평가한다. 독성평가를 위해 실험용 쥐와 토끼를 이용하며, 쥐에 대해 단회 경구독성과 경피독성 시험을 실시하고, 토끼에 대해 안점막자극시험 및 피부자극 시험을 시행한다. 본 시험에 이용한 천연 생물방제물질은 목재부후균과 흰개미에 대한 항진균활성 및 살충활성이 조사된 족두리풀 추출물을 적용하였다. 쥐에 대한 단회 경구투여한 결과 $LD_{50}$ 값이 수컷 4,000 mg/kg 이상, 암컷 2,000 mg/kg 이상으로 판정되었으며, 단회 경피 투여한 결과 $LD_{50}$ 값이 암수 모두 10,000 mg/kg 이상으로 판정되었다. 토끼의 눈에 대한 자극시험에서는 무자극성으로 판정되었으며, 피부에 대해서는 약한 자극성이 있는 물질로 판단되었다. 본 연구를 통해 천연 생물방제물질인 족두리풀 추출물의 안전성을 동물실험으로 확인함으로써 화학 물질의 안전성 검증을 위한 기본적인 유해성 평가 방법으로 제시하고자 한다.