• Interaction and multiscale mechanics
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• 제1권2호
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• pp.251-278
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• 2008

In this study, we investigate the discontinuous-derivative treatment at the gas-liquid interface in underwater explosion (UNDEX) problems by using the Moving Least Squares-Smoothed Particle Hydrodynamics (MLS-SPH) method, which is known as one of the particle methods suitable for problems where large deformation and inhomogeneity occur in the whole domain. Because the numerical oscillation of pressure arises from derivative discontinuity in the UNDEX analysis using the standard SPH method, the MLS shape function with Discontinuous-derivative Basis Function (DBF) that is able to represent the derivative discontinuity of field function is utilized in the MLS-SPH formulation in order to suppress the nonphysical pressure oscillation. The effectiveness of the MLS-SPH with DBF is demonstrated in comparison with the standard SPH and conventional MLS-SPH though a shock tube problem and benchmark standard problems of UNDEX of a trinitrotoluene (TNT) charge.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.43-46
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• 2004

Explosive chemicals have been major soil and groundwater contaminants especially in the nations with active military activities. Of these explosives, 2,4,6-trinitrotoluene (TNT) is the most refractory one due to its structural characteristics. Although its efficient reduction by Fe(0) is well-known, the reduction products - mainly aminotoluenes - still possess toxicities to terrestrial biota, and are resistant to biological degradation. In this study, therefore, abiotic transformation of TNT reduction products via oxidative-coupling reaction was evaluated using Mn oxide which is ubiquitous in natural soils. The transformation efficiency is increased with the number of amino groups. Considering the very efficient reduction rate of TNT by Fe(0), Mn oxide can be successfully used for the removal of TNT reduction products.

• 통합자연과학논문집
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• 제2권1호
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• pp.37-40
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• 2009

Synthesis and characterization of alkyl-capped nanocrystalline silicon (R-n-Si) have been achieved from the reaction of silicontetrachloride with magnesiumsilicide. Surface of silicon nanocrystal has been derivatized with various alkyl groups (R=methyl, n-butyl, etc.). Silicon nanoparticles have been also obtained by the sonication of luminescent porous silicon. Former exhibits an emission band at 360 nm, but latter exhibits an emission band at 680 nm. In this study very sensitive detection of TNT (2,4,6-trinitrotoluene), DNT (2,4-dinitrotoluene), NB (nitrobenzene), and PA (picric acid) has been achieved in gas phase with porous silicon using photoluminescence quenching of the silicon crystallites as a transduction mode. Porous silicon are electrochemically etched from crystalline silicon wafers in an aqueous solution of hydrofluoric acid. We have characterized these silicon nanoparticles by Luminescence Spectrometer (LS 55).

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.235-238
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• 2002

Microorganisms were isolated from military shooting site. Aerobic batch reactor and resting cell condition experiments were carried out using isolated microorganisms. Experiments were examined at room temperature on shaker and ten-roll mixer. During 10 days of reaction time, TNT was degraded 15.51 ~ 22.47 mg/L from initial concentration(31$\pm$1 mg/L) by aerobic batch reactor. Aerobic resting cell condition experiments were carried out ill phosphate buffer with 58($\pm$1) mg/L TNT at pH of 6.0($\pm$0.2). TNT was degraded 67.8% of initial concentration. The mai or component was found 4-ADNT(4-Aminodinitrotoluene).

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.314-317
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• 2003

Plants may enhance the remediation of munitions at contaminated soils using various natural processes. A computer model can be used as a valuable tool for assisting phytoremediation by predicting the transport and fate of target contaminants at remediation sites. For this research, modeling of phytoremediation and bioremediation of soil contaminated with 2, 4, 6-trinitrotoluene (TNT) was studied. Indian mallow (Abutilion avicennae) was grown in columns packed with 126mg TNT/kg contaminated soils for 50 days and a simulation model was developed to simulate the transport and fate of TNT and its breakdown products interacting with plant roots in a partially saturated soil. The column test showed the substantially enhanced reduction of TNT and greater soil microbial activity in Indian mallow planted soil compared to unplanted soil. The model successfully simulated the fate of TNT and by-products in phytoremediation. The results suggested that plants could provide favorable environments for reduction of TNT.

• 통합자연과학논문집
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• 제3권1호
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• pp.19-23
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• 2010

A simple and rapid method is described for detecting nitroaromatic explosives in air or seawater with the use of photoluminescent organosilicon compounds. The synthesis, spectroscopic characterization, and fluorescence quenching efficiency of silafluorenes are reported. Silafluorenes were synthesized from the reduction of dilithiobiphenyl with dichlorosilanes. Two silafluorenes were used for the detection of nitroaromatic compounds. Detection of nitroaromatic molecules, such as 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), and picric acid (PA), has been explored. A linear Stern-Volmer relationship was observed for the first three analytes. Fluorescence spectra of silafluorenes obtained in either toluene solutions or thin films displayed no shift in the maximum of the emission wavelength. The photoluminescence quenching occurs by a static mechanism.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.90.1-90.1
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• 2013

Nature utilizes various of the colorization process. Some species of birds can express their mood of tempers by changing their collagen structures on skin. For example, turkey can change their skin color by expansion of the collagen structures, which are associated with the distinct color changes. Here, we developed bioinspired virus-based colorimetric sensors which can be genetically tuned for target molecule. Using M 13 bacteriophage, we fabricated responsive self-assembled color matrices composed of quasi-ordered fiber bundle structures. These virus matrices can exhibit color change by stimuli through fiber bundle structure modulation. Upon exposure of volatile organic compounds, the resulting multi-colored matrices exhibited distinct color changes with different ratios that can be recognized by the naked eyes. Using the directed evolutionary approaches, we genetically engineered the virus matrix to incorporate binding motif for explosive detection (i.e., trinitrotoluene (TNT)). Through utilizing a common handheld device (i.e., iPhone), we could distinguish TNT molecules down to 20 ppb in a selective manner. Our novel biomimetic virus colorimetric sensor can overcome current limitation for low response selectivity.

• Advances in concrete construction
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• 제15권4호
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• pp.229-239
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• 2023

Anti-tank weapons are among the infantry weapons used by the armies of many countries. Anti-tank rockets and explosives such as TNT, generally used for armour piercing, are also frequently used in terrorist attacks. These attacks damage the protection facilities built from reinforced concrete. Rockets or similar explosives' rapid speed and burst temperatures pierce reinforced concrete during strikes, resulting in casualties and damage to crucial strategic structures. This study aimed to devise an economic and applicable reinforced concrete plate that could absorb the impact of anti-tank rockets and Trinitrotoluene (TNT) type explosives. Therefore, 5 different samples, produced from C50 reinforced concrete and 150×150 cm in size, were formed by combining plates of different numbers and thicknesses. Also, a sample, which was a single thick plate, was prepared. In destructive testing, Rocket Propelled Grenade (RPG-7) was used as the anti-tank rocket launcher. As a result of this study, the impact damage was reduced with hollow concrete plate geometries, and recommendations were developed for complete prevention.

• 한국지하수토양환경학회지:지하수토양환경
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• 제6권4호
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• pp.3-11
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• 2001

TNT를 제거하기 위한 식물종을 선정하기 위해 8종의 대표적인 야초류를 이용하여 TNT 식물독성 임계점을 측정하였다. 독성 임계점은 TNT 농도변화에 대한 발아율, 유식물의 뿌리와 지상부의 생장율, 생체량 및 수분 흡수 능력 등을 비교하여 결정하였다. TNT가 식물에게 미치는 독성효과는 오염물의 농도와 식물종에 따라 다르게 나타났다. 60-80mgTNT/L 농도는 어저귀, 식용피, 자귀풀 종자의 발아율에 영향을 미치지 못하였다. 발아 후 14일동안 어저귀, 식용피, 자귀풀의 뿌리 생장에 있어 식물 독성 임계점(50%) 농도는 5-40 mgTNT/L이며 지상부 생장은 50-73mgTNT/L, 생체량은 68-99mgTNT/L이다. 뿌리와 지상부의 길이, 생체량은 TNT농도가 증가함에 따라 감소하였으며 수분 흡수량도 감소하였다. 야초류의 서로 다른 독성 임계점을 비교해 보면 뿌리 길이 > 지상부 길이 > 생체량 > 발아율 순으로 TNT에 대해 민감하게 반응하였다. 실험 결과, 8종의 식물 중에서 어저귀와 자귀풀은 TNT에 대해 내성을 지닌 종으로 판명되었다.

• 한국미생물·생명공학회지
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• 제32권3호
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• pp.230-237
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• 2004

균주 Pseudomonas sp. HK-6로부터 2,4,6-trinitrotoluene (TNT)의 대사 과정에서 유도되는 nitroreductase (NTR)를 분리 및 정제하여 다양한 특성조사를 실시하였다. NTR은 균주 HK-6의 세포추출물로부터 ammonium sulfate 침전, DEAE-sepharose, 그리고 Q-sepharose chromatography의 일련의 과정을 통하여 분리되었고, NTR의 활성을 가지는 세개의 다른 fractions를 확인하였다. 균주 HK-6의 NTR fractions I, II, 그리고 III의 비 활성은 각각 4.85 unit/mg, 5.47 unit/mg, 5.01 unit/mg으로 측정되었으며, 세포추출물에 비해 각각 9.0배, 10.1배, 9.3배 농축된 것으로 나타났다. SDS-PAGE에서 측정된 균주 HK-6의 NTR fractions I, II 그리고 III의 분자량은 모두 약 27 kDa으로 확인되었다. 정제된 NTR의 활성에 온도, pH, 금속 이온, 억제 물질의 효과와 기질 특이성 등에 대한 물리화학적 특성 조사를 실시하였다. 균주 HK-6의 NTR fractions I, II, 그리고 III의 적정온도는 $25～35^{\circ}C$ 확인되었고, 모두 $30^{\circ}C$에서 최대 활성을 나타내었으며, 이들 효소 활성의 적정 pH는 7.0～8.0이었고, 최적 pH는 7.5로 확인되었다. TNT에 대한 HK-6의 NTR fractions I, II, 그리고 III의 활성은 금속 이온 $Ag^{＋}$ , $Cu^{2＋}$ , 그리고 $Hg^{V}$ 에 의해서 약 70%이상 저해되었으며, $Mn^{2+}$ 또는 $Ca^{2＋}$ 에 의해서 약 20～50%로 활성이 억제되었다. 그러나 $Fe^{2＋}$ /첨가 시에는 효소의 활성에 크게 영향을 미치지 않는 것으로 나타났다. NTR의 활성에 대한 억제물질의 영향은 $\beta$-mercaptoethanol 첨가 시에 효소의 활성이 모두 억제되었고, dithiothreitol, EDTA, 그리고 NaCl 첨가시에도 활성이 감소하는 것으로 확인되었다. TNT와 그 유사기질을 이용하여 HK-6에서 분리된 NTR의 기질 특이성을 조사한 결과, TNT, nitrobenzene, 그리고 RDX에 대해서는 비교적 활성이 높게 나타났으나 2,6-DNT와 2,4-DNT에서는 낮은 활성을 나타내는 것으로 확인되었다.