초고성능 콘크리트(UHPC)는 낮은 물-결합재비(W/B), 고성능 감수제(SP), 혼화재 및 강섬유(Steel Fiber)의 혼입으로 일반 콘크리트보다 유동성, 강도 등에서 월등히 우수한 성능을 지닌 건설 재료이다. 본 연구에서는 진동밀로 분쇄하여 시멘트의 분말도를 6000cm2/g급 까지 높여 최적의 초고성능 모르타르를 제작하였다. 또한, UHPC의 특성상 시멘트, 혼화재뿐만 아니라 화학 혼화제 혼입량에 따라 물성에 많은 차이를 나타내기 때문에 최적의 화학 혼화제를 도출하기 위하여 고성능 혼화제에 따른 물성 평가 실험도 수행하였다. 분쇄된 시멘트를 활용한 초고성능 모르타르의 유동성, 강도 등 물성 테스트를 진행하였으며, 경제성을 고려하여 강섬유와 기타 혼화재를 혼입하지 않고 목표 물성을 달성하고자 하였다. 실험결과, 모든배합에서 플로우 값은 목표치 180±10mm를 확보하였으며, W/B 20%, SP 0.8%에서 최대 압축강도 90MPa, 휨강도 16.8MPa까지 나타났다.

환경친화적 생물적방제를 위해 수출딸기온실에서 해충인 점박이응애 밀도 감소 효율을 화학적방제와 생물적방제로 나누어 동일한 크기의 동일한 온실에서 각각 비교하였다. 생물적방제 온실은 점박이응애의 천적인 칠레이리응 애만을 이용하였고, 화학적방제 온실은 일반 화학합성 농약을 이용하여 점박이응애의 밀도를 조절하였다. 화학적방제 온실에 비해 생물적방제 온실에서 점박이응애 모든 태의 밀도가 낮게 관찰되었으며, 생물적방제를 위한 비용이 화학적방제에 비해 낮았다. 이러한 결과는 수출딸기의 주요해충인 점박이응애의 방제에 칠레이리응애를 이용한 생물적방제가 가능한 것을 나타내고 있다.

Chemical decontamination of primary systems in a nuclear power plant (NPP) prior to commencing the main decommissioning activities is required to reduce radiation exposure during its process. The entire process is repeated until the desired decontamination factor is obtained. To achieve improved decontamination factors over a shorter time with fewer cycles, the appropriate flow characteristics are required. In addition, to prepare an operating procedure that is adaptable to various conditions and situations, the transient analysis results would be required for operator action and system impact assessment. In this study, the flow characteristics in the steady-state and transient conditions for the chemical decontamination operations of the Kori-1 NPP were analyzed and compared via the MARS-KS code simulation. Loss of residual heat removal (RHR) and steam generator tube rupture (SGTR) simulations were conducted for the postulated abnormal events. Loss of RHR results showed the reactor coolant system (RCS) temperature increase, which can damage the reactor coolant pump (RCP)s by its cavitation. The SGTR results indicated a void formation in the RCS interior by the decrease in pressurizer (PZR) pressure, which can cause surface exposure and tripping of the RCPs unless proper actions are taken before the required pressure limit is achieved.

생물 및 화학물질 등의 대량살상무기들을 이용한 테러공격은 매우 위협적인 테러공격 가운데 하나이다. 미국의 분류에 따르면 대량살상무기 는 테러공격에 이용되었을 때 다수의 사상자들을 발생시킬 수 있는 화학 물질, 생물학물질, 방사능과 핵물질, 그리고 이러한 물질들을 이용해 만들어진 폭발물을 의미한다. 이와 같은 대량살상무기가 테러공격에 이용 되는 것에 대한 대응책으로 미국정부는 테러리스트나 악의적인 행위자들로부터 이와 같은 물질들에 대한 접근을 차단하고, 대량살상무기들과 관련된 기술적 트렌드를 파악·대응하며, 그리고 대량살상무기관련 물질들을 취급 저장하는 정부기관들과 민간 기업들의 대응능력 강화를 위한 대책을 마련, 운용하고 있다. 이와 같은 미국 정부의 대량살상무기의 대응사례는 국내의 대테러정책에 좋은 참고사례가 된다. 국내의 경우, 대테러정책과 관련하여 테러이용 수단의 안전관리강화에 대한 지적과 논의가 계속되고 있다. 이 연구는 이와 같은 맥락에서 미국 연방정부의 생물, 화학물질 관리 사례에 대해 연구하고 시사점을 도출하였다. 특히 이 연구는 미국의 생물 및 화학물질의 안전관리사례와 법률 등을 분석하였고, 이에 더불어 대테러활동 지원을 위해 설립된 연구기관의 과학적이고 혁신적인 활동을 소개하였다. 연구 수행을 위해 다양한 관련 학술논문과 정부보고서 등을 문헌분석 하였다. 연구의 결론과 논의 부분에서 이 연구의 분석결과를 토대로 국내에 적용될 만한 정책대응을 제안하였다.

PURPOSES : The purpose of this study is to evaluate the asphalt binder properties using FTIR analysis. METHODS : To investigate the chemical properties of asphalt binders, FTIR tests were performed. Recently, FTIR was used for quantification under various aging conditions. Three scans were averaged for each sample within the wavenumber range of 4000 to 400 cm-1, at a resolution of 4 cm-1 (default Simatech software settings). To determine the oxidation of the extracted asphalt binder and the remaining TCE solution in the extracted asphalt binder, the penetration test was adopted and compared. To track the changes in the chemical composition of the aged bitumens, the ATR spectrum of each sample was analyzed, both qualitatively and quantitatively. The qualitative analysis involved identifying characteristic absorption peaks for the functional group of interest, such as polymer components, carbon and sulfur oxidation products, and polar aromatics. RESULTS : The asphalt binder is easily oxidized in air during FTIR testing. To reduce the oxidization of the asphalt binder, the asphalt binder must avoid air contact to measure constant results. Sometimes, the extracted asphalt binder has a residual solvent (TCE), which affects the evaluation of the extracted asphalt binder rheology, such as absolute viscosity and penetration testing. To solve this problem, the research team adopted the FTIR test method. First, the TCE was scanned with FTIR to obtain the chemical characteristics of TCE. After that, the extracted asphalt binder was scanned and the FTIR spectra were compared with those of TCE. If there is a TCE in the extracted asphalt binder, a typical peak was found in the spectrum. Thus, it is possible to estimate the content of the TCE remaining in the extracted asphalt binder via the FTIR test method. CONCLUSIONS : It is possible to evaluate the aging of asphalt binder through FTIR analysis used for the analysis of the chemical structure of asphalt. In addition, during FTIR analysis, the sample is required to avoid air contact to obtain accurate results. FTIR analysis was conducted to confirm whether the solvent (TCE) remained in the extracted asphalt binder and it was confirmed that the penetration increased by a factor of two when the solvent remained. This suggests that it is difficult to control the quality of the asphalt mixture by controlling the amount of recycled additive, as well as the aging of the extracted asphalt binder.

본 연구에서는 석유화학제품 산적운송선(화학유조선)에 의한 해상운송 과정에서 발생한 위험․유해물질(HNS) 관련 해상화학사 고에 대하여 국내 및 국외의 주요 사례를 조사․분석함으로써 얻은 교훈을 소개하고, 이러한 교훈을 바탕으로 국내 해상HNS 교육과정 개 선방안을 제시하였다. 6건의 사고사례를 통하여 얻은 교훈을 1) 사고관련정보, 2) 안전, 3) 오염, 4) 대응, 5) 구난, 6) 기타와 같은 6개 분야로 분류하였다. 각 분야의 세부항목별로 요약된 교훈을 바탕으로 해양환경교육원(MERTI) 유해액체물질운반선 해양오염방지관리인 교육과정을 현행 8개 교과목(16시간)의 2일간 교육을 16개 교과목(24시간)의 3일간 교육으로 개선하는 방안을 제시하였으며, 또한 해양경찰교육원 (KCGA) 전문교육 해양화학사고대응 과정을 현행 15개 교과목(35시간)의 5일간 교육을 32개 교과목(48시간)의 6일간 교육으로 개선하는 방안을 제시하였다. 이러한 연구결과는 해상화학사고 대응에 관한 경험과 교훈을 서로 공유하는 데에 기여하고, 해상HNS사고에 대비한 대응 인력 교육․훈련과정 개선의 기초자료로 활용될 수 있을 것으로 기대된다.

This study investigated the effect of the addition of various levels of pig head meat (HM) as a substitute for rear leg meat (RLM) on the physico-chemical quality characteristics of non-emulsified, smoked, and cooked sausage during refrigerated storage. Sausages were prepared in four variations according to the proportion (0%, 10%, 20%, or 30%) of HM added and maintained at 4°C. Quality measurements were taken for 28 days. The sausages added with the addition of 20% and 30% HM had significantly (p<0.05) higher moisture and lower protein content compared to those without the addition of HM. The pH value during the storage period was higher (p<0.05) in the sausages to which the HM had been added than in those without HM. The sausages with 30% HM showed the lowest (p<0.05) L* and b* values and the highest (p<0.05) a* value during the storage period. The 2-thiobarbituric acid reactive substances (TBARS) content, hardness, cohesiveness, springiness, gumminess, and chewiness of the sausages showed no significant variations with the addition of various levels of HM. These data suggest that RLM could be substituted with 30% HM because it does not negatively affect the quality of the non-emulsified sausage. However, a further study on sausages made with 100% HM instead of RLM may be needed to improve its utilization.

This study explores reducing the oxygen content of a commercial Ti-48Al-2Cr-2Nb powder to less than 400 ppm by deoxidation in the solid state (DOSS) using Ca vapor, and investigates the effect of Ca vapor on the surface chemical state. As the deoxidation temperature increases, the oxygen concentration of the Ti-48Al-2Cr-2Nb powder decreases, achieving a low value of 745 ppm at 1100oC. When the deoxidation time is increased to 2 h, the oxygen concentration decreases to 320pp m at 1100oC, and the oxygen reduction rate is approximately 78% compared to that of the raw material. The deoxidized Ti-48Al-2Cr-2nb powder maintains a spherical shape, but the surface shape changes slightly owing to the reaction of Ca and Al. The oxidation state of Ti and Al on the surface of the Ti-48Al-2Cr-2Nb powder corresponds to a mixture of TiO2 and Al2O3. As a result, the peaks of metallic Ti and Ti suboxide intensify as TiO2 and Al2O3 in the surface oxide layer are reduced by Ca vapor deposition

Using lanthanum zinc oxide (LZO) film with the ion-beam irradiation, uniform and homogeneous liquid crystal (LC) alignment was achieved. To fabricate the LZO thin film on glass substrate, solution process was conducted as a deposition method. Cross-polarized optical microscopy (POM) and the crystal rotation method reveal the state of LC alignment on the ion-beam irradiated LZO film. Between orthogonally placed polarizers, POM image showed constant black color with regular transmittance. Furthermore, collected incidence angle versus transmittance curve from the crystal rotation method revealed that the LC molecules on the ion-beam irradiated LZO film were aligned homogeneously. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were conducted to reveal the relationship between the ion-beam irradiation and the LC alignment. The ion-beam irradiation changed the LZO film surface to rougher than before by etching effect. Numerical roughness values from AFM analysis supported this phenomenon specifically. XPS analysis showed the chemical composition change due to the ion-beam irradiation by investigation of O 1s, La 3d and Zn 2p spectra. The ion-beam irradiation induced the breakage of chemical bonds in the LZO film surface and this occurred surface chemical anisotropic characteristics for uniform LC alignment.

Continuous synthesis of high-crystalline carbon nanotubes (CNTs) is achieved by reconfiguring the injection part in the reactor that is used in the floating catalyst chemical vapor deposition (FC-CVD) process. The degree of gas mixing is divided into three cases by adjusting the configuration of the injection part: Case 1: most-delayed gas mixing (reference experiment), Case 2: earlier gas mixing than Case 1, Case 3: earliest gas mixing. The optimal synthesis condition is obtained using design of experiment (DOE) in the design of Case 1, and then is applied to the other cases to compare the synthesis results. In all cases, the experiments are performed by varying the timing of gas mixing while keeping the synthesis conditions constant. Production rate (Case 1: 0.63 mg/min, Case 2: 0.68 mg/min, Case 3: 1.29 mg/min) and carbon content (Case 1: 39.6 wt%, Case 2: 57.1 wt%, Case 3: 71.6 wt%) increase as the gas-mixing level increases. The amount of by-products decreases stepwise as the gas-mixing level increases. The IG/ID ratio increases by a factor of 7 from 10.3 (Case 1) to 71.7 (Case 3) as the gas-mixing level increases; a high ratio indicates high-crystalline CNTs. The radial breathing mode (RBM) peak of Raman spectrograph is the narrowest and sharpest in Case 3; this result suggests that the diameter of the synthesized CNTs is the most uniform in Case 3. This study demonstrates the importance of configuration of the injection part of the reactor for CNT synthesis using FC-CVD.

페로몬에 기반한 해충방제 기술은 페로몬이 동정되는 곤충의 수가 지수적으로 증가함에 따라 더욱 성공가능성이 높은 전략이 되고 있다. 이 연구는 애기유리나방, [Synanthedon tenuis (Butler) (Lepidoptera: Sesiidae)]의 성페로몬((Z, Z )-3, 13-octadecadien-1-ol.)에 의한 화학 통신교란(pheromone-mediated chemical communication disruption, PCD)의 효과에 대한 것이다. 본 PCD법은 우리나라 전남 순천과 경 남 진주의 2곳의 단감 과수원에서 2016년과 2017년에 총 4회 수행되었으며, PCD의 효과는 성페로몬 처리구와 무처리구에서의 평가용 트랩 포 획수로 나타내었다. 성페로몬 처리구의 평가용 트랩에 유인된 수컷 성충수는 무처리구에 유인된 수보다 유의하게 적었으며, 유인수 감소효과는 95.2~100% (평균 98.8±1.2%)이었다. 이러한 결과로 볼 때 성페로몬에 기반한 애기유리나방의 방제가 가능할 것으로 판단된다

Several factors, including genetic and environmental insults, impede protein folding and secretion in the endoplasmic reticulum (ER). Accumulation of unfolded or mis-folded protein in the ER manifests as ER stress. To cope with this morbid condition of the ER, recent data has suggested that the intracellular event of an unfolded protein response plays a critical role in managing the secretory load and maintaining proteostasis in the ER. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and hydrophilic bile acid that is known to inhibit apoptosis by attenuating ER stress. Numerous studies have revealed that TUDCA affects hepatic diseases, obesity, and inflammatory illnesses. Recently, molecular regulation of ER stress in tooth development, especially during the secretory stage, has been studied. Therefore, in this study, we examined the developmental role of ER stress regulation in tooth morphogenesis using in vitro organ cultivation methods with a chemical chaperone treatment, TUDCA. Altered cellular events including proliferation, apoptosis, and dentinogenesis were examined using immunostaining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, altered localization patterns of the formation of hard tissue matrices related to molecules, including amelogenin and nestin, were examined to assess their morphological changes. Based on our findings, modulating the role of the chemical chaperone TUDCA in tooth morphogenesis, especially through the modulation of cellular proliferation and apoptosis, could be applied as a supporting data for tooth regeneration for future studies.

국제해사기구(IMO)의 황함유량 규제에 따르는 저유황연료유는 생산 공정에 따라 다양한 물리화학적 특성을 가지게 된다. 본 연구는 저유황연료유 및 저유황-고유황 혼합연료유의 물리화학적 특성연구 결과를 해양오염 방제대응의 기초자료로 활용하고자 한다. 연구에 사용된 혼합연료유는 황함유량이 0.46 mass%인 저유황연료유와 0.36 mass%인 저유황연료유에 고유황연료유를 25, 50, 75 mass% 혼합하여 제조하였다. 이 혼합연료유에 대해 동점도, 유동점 및 Saturates, Aromatics, Resins, Asphaltenes(SARA)분포 등 물리화학적 특성에 대해 실험실 연구를 하였다. 동점도가 높고 유동점이 낮은 특징의 고유황연료유가 75 mass% 혼합함에 따라, 혼합연료유의 동점도는 350.2 %까지 증가 하였으며, 유동점이 23℃와 -11℃의 저유황연료유는 각각 -3℃ 및 -6℃까지 유동점이 내려가거나 올라갔다. Asphaltenes 분포가 적은 저유황연료유에 고유황연료유를 혼합함에 따라, Saturates분포는 68.8 %까지 감소하고, Asphaltenes분포는 1,417 %까지 크게 증가하였다.

농촌지역에서는 농업활동의 영향에 의한 질산성질소 오염이 천부지하수를 생활용수나 먹는물로 사용하는데 큰 장애요인이 되고 있다. 본 연구에서는 충남 예산군 효교리 농업지역의 천부지하수의 수질특성을 토지용도 및 토양층의 화학성분과 연계하여 고찰하였다. 지하수의 NO3-N 평균 농도는 생활용수와 농업용수 수질 기준을 초과하며, 이는 비료, 축산폐수, 생활하수 등의 인위적인 오염원으로부터 유래하는 것으로 판단된다. 연구지역 지하수 수질형은 주로 Ca(Na)-Cl형에 속하는 것으로 나타나며, 일반적인 천부지하수의 수질형인 Ca-HCO3형과는 다르다. 논 및 기타(상류, 목장, 주거) 지역과 밭 지역으로 구분하여 지하수의 NO3-N 농도를 비교한 결과, 밭 지역의 NO3-N의 평균 농도는 22.8 mg L−1이고, 논 및 기타 지역의 NO3-N 평균 농도는 7.7 mg L−1로서 밭 지역의 NO3-N의 평균 농도가 높게 나타난다. 이는 논지역이 낮은 투수성을 가지고, 밭지역은 높은 투수성을 가지기 때문이다. Mann-Kendall 검정과 Sen 검정에 의한 경향성 분석 에 의하면, NO3-N 농도는 매년 0.011 mg/L 정도로 매우 약한 감소 추세를 보여주고 있으며, 이는 현재 지하수내 NO3-N 농도가 거의 평형상태에 있음을 지시한다. 한편 SO4 2− 농도는 매년 −15.48% 씩 감소하며, HCO3 − 농도는 매년 −13.75% 씩 감소하는 것으로 나타났다. 입도분석에 의한 수리전도도는 지표하 5 m까지의 심도에서 평균 1.86×10−5 cm s−1을 보이며, 모래층에서는 1.03×10−4 cm s−1을 그리고 실트층에서는 2.50×10−8 cm s−1을 보인다.

Numerous chemical modifications on activated carbon such as acidic conditioning, thermal treatment and metal impregnation have been investigated to enhance adsorption capacities of micropollutants in water treatment plants. In this study, chemical modification including acidic, alkaline treatment, and iron-impregnation was evaluated for adsorption of 2,4-dichlorophenol (2,4-DCP). For Fe-impregnation, three concentrations of ferric chloride solutions, i.e., 0.2 M, 0.4 M, and 0.8 M, were used and ion-exchange (MIX) of iron and subsequent thermal treatment (MTH) were also applied. Surface properties of the modified carbons were analyzed by active surface area, pore volume, three-dimensional images, and chemical characteristics. The acidic and alkaline treatment changed the pore structures but yielded little improvement of adsorption capacities. As Fe concentrations were increased during impregnation, the active adsorption areas were decreased and the compositional ratios of Fe were increased. Adsorption capacities of modified ACs were evaluated using Langmuir isotherm. The MIX modification was not efficient to enhance 2,4-DCP adsorption and the MES treatment showed increases in adsorption capacities of 2,4-DCP, compared to the original activated carbon. These results implied a possibility of chemical impregnation modification for improvement of adsorption of 2,4-DCP, if a proper modification procedure is sought.

Large-scale cultivation of Microcystis aeruginosa in different light conditions was conducted for verifying the cell growth in a greenhouse system. Environmental and chemical parameters of the large-scale culture medium were measured for analyzing the interaction between M. aeruginosa and its symbiotic bacteria. During cultivation, a difference in cell growth pattern was observed between control (natural light) and lightlimited groups (reduction of blue, green, and blue/green light, respectively). Comparing the control group, the light reduced groups showed slow and delayed cell growth through the cultivation period. Also, there is differences in the consuming pattern of total nitrogen and total phosphorus which indicated that the possibility of interaction between M. aeruginosa and symbiotic bacteria.

Chungyuk-jang is one of korean traditional soy food made by boiling with meat, seafood and soybean which is fermented after roasting. To investigate the difference in the physicochemical characteristics of the Chungyuk-jang fermented with roasted soybean in different conditions, Chungyuk-jang was made from soybean roasted on the three condition, 140oC for 21 min (CY140), 180oC 9.5 min (CY180), 220oC 6 min (CY220) which was decided by pre-test and compared to one made without roasting (CY0). The moisture of Chungyuk-jang was 79.98~81.87% and pH was 6.15~6.25. The lightness and yellowness of CY0 was higher than Chungyuk-jang made of roasted bean whereas redness and brown pigment was the highest on CY220. The contents of free sugar of CY140 was the highest among the treatment. The contents of amino-N of Chungyuk-jang (CY140, CY190, CY220) was higher significantly than CY0. The contents of total free amino acid and glutamic acid was highest on fermented soybean roasted for 140oC, 21 min (CY140) and followed by fermented soybean roasted on 180oC 9.5 min (CY180), 220oC 6 min (CY220) and CY0 (without roasting).

This study was conducted to investigate the effect of dietary total mixed ration (TMR) supplementation and dry-aging period on the physico-chemical and sensory quality of striploin (longissimus lumborum) from multiparous Hanwoo cows. The experimental cows were divided into two treatments (n=3/treatment) according to the type of feed: in one treatment (slaughter age: 87±6 months old, parity: 5±1) the cows were fed on TMR for 7 months before slaughter, while in the other treatment (slaughter age: 83±9 months old, parity: 5±2) the cows were fed on concentrate and rice straw (CRS) for the whole rearing period. After slaughtering, the striploins were dry-aged for 20 or 40 days at 2±1℃, 85% relative humidity and 2 m/sec air flow velocity and then utilized for quality measurements. The pH value, cooking loss, and hypoxanthine content were higher (p<0.05) for the striploins dry-aged for 40 days than for those dry-aged for 20 days. Notably, the inosine 5’-monophosphate content was decreased (p<0.05) by increasing the dry-aging time. With regard to microbiological quality, the striploins dry-aged for 40 days exhibited lower (p<0.05) lactic acid bacteria counts and higher (p<0.05) coliform counts than those dry-aged for 20 days. Moreover, the tenderness and overall liking scores based on sensory evaluation were higher (p<0.05) for the dry-aged striploins of the TMR treatment and those dry-aged for 40 days than for the CRS treatment and those dry-aged 20 days, respectively. These findings suggest that dietary TMR supplementation leads to an increase in the sensory preference of dry-aged striploins from multiparous Hanwoo cows, and alteration of the CRS into the TMR may improve the quality of dry-aged Hanwoo beef.