The present polymer have a conjugated polymer backbone system with the designed substituents. The photoluminescence peak of polymer was observed at 525nm, which is corresponded to the photon energy of 2.36 eV and the band gap of poly(EBA) was 2.38 eV. The cyclovoltamograms of the polymer exhibited the irreversible electrochemical behaviors. It was found that the kinetics of the redox process of this conjugated polymer might be mainly controlled by the diffusion process from the experiment of the oxidation current density of polymer versus the scan rate.

We developed a facile methodology for fabricating a free-standing mixed-matrix membrane (MMM) containing covalently incorporated vinyl-functionalized UiO-66-CH=CH2 particles up to 60 wt% by utilizing thiol-ene photopolymerization. FTIR, TGA, SEM, EDX, and XRD strongly supported the fact that the desired MMM containing well-dispersed UiO-66-CH=CH2 particles was successfully produced by C–S bond formation. The MMM was highly flexible and showed improved mechanical properties compared to the pristine polymeric membrane, indicating that the covalently immobilized UiO-66-CH=CH2 particles were homogeneously distributed in the polymer matrix. Gas permeability across the MMM was significantly enhanced compared with the pristine polymeric membrane as diffusion of the gas molecules was facilitated in the porous space of the MOF.

Metallic tantalum powder is manufactured by reducing tantalum oxide (Ta2O5) with magnesium gas at 1,073–1,223 K in a reactor under argon gas. The high thermodynamic stability of magnesium oxide makes the reduction reaction from tantalum oxide into tantalum powder possible. The microstructure after the reduction reaction has the form of a mixture of tantalum and magnesium oxide, and the latter could be entirely eliminated by dissolving in weak hydrochloric acid. The powder size in SEM microstructure for the tantalum powder increases after acid leaching in the range of 50–300 nm, and its internal crystallite sizes are observed to be 11.5 to 24.7 nm with increasing reduction temperatures. Moreover, the optimized reduction temperature is found to be 1,173 K as the minimum oxygen concentration is approximately 1.3 wt.%.

배경목적: 내시경 초음파 유도하 췌장 저류액 배액은 효과적인 시술이나 이 시술에 특화된 맞춤형 부속기구는 부족한 실정이다. 이 연구의 목적은 내시경 초음파 유도하 경위장관 배액술 전용으로 새로 고안된 양측 플랜지가 있는 완전피막형 금속 스텐트의 유용성을 평가하고자 하였다. 방법: 동물연구는 한 마리의 개를 대상으로 하였고 임상연는 췌장 저류액을 가진 5명의 환자 (5명은 췌장가성낭종, 1명은 벽 형성 췌장괴사)를 대상으로 하여 내시경 초음파 유도하 배액술을 시행하였다. 연구의 성과는 기술적, 임상적 성공여부, 합병증, 스텐트 제거 가능 여부로 판단하였다. 결과: 동물연구에서 스텐트는 내시경 초음파 유도하 경십이지장 접근으로 합병증 없이 성공적으로 유치되었다. 시술 직후 시행한 부검에서 담낭-십이지장 연결은 온전하였다. 6명의 환자에서 모두 스텐트는 성공적으로 유치되었다. 모든 환자에서 시술후 합병증과 스텐트 이탈은 없었다. 결론: 새로 고안된 양측 플랜지가 있는 완전피막형 금속스텐트를 사용한 췌장저류액의 내시경 초음파 유도하 경위장관 배액술은 기술적으로 가능하였고 심각한 합병증은 없었다. 스텐트 선단부의 맞춤형 플랜지 형상은 시술의 효과를 배가시켰다.

Nitrogen is a serious contaminant in natural gas because it decreases the energy density. The natural gas specification in South Korea requires a N2 content of less than 1 mol%. Thus, cost-effective N2 removal technology from natural gas is necessary, but until now the only option has been energy-intensive processes, e.g., cryogenic distillation. Using porous materials for the removal process would be beneficial for an efficient separation of CH4/N2 mixtures, but this still remains one of the challenges in modern separation technology due to the very similar size of the components. Among various porous materials, metal-organic frameworks (MOFs) present a promising candidate for the potential CH4/N2 separation material due to their unique structural flexibility. A MIL-53(Al), the most well-known flexible metal-organic framework, creates dynamic changes with closed pore (cp) transitions to open pores (ops), also called the ‘breathing’ phenomenon. We demonstrate the separation performance of CH4/N2 mixtures of MIL-53(Al) and its derivative MIL-53-NH2. The CH4/N2 selectivity of MIL- 53-NH2 is higher than pristine MIL-53(Al), suggesting a stronger CH4 interaction with NH2.

Li-Cd 합금을 이용한 환원추출방식을 LiCl-KCl 기반의 drawdown 공정에 적용하게 되면, LiCl-KCl 공융염의 조성이 파괴되므로 공정온도를 높여야 하며, 전해정련 및 전해제련과 같은 공정에 LiCl-KCl 용융염을 재사용할 수 없게 된다. 따라서, 본 연구에서는 공융염 조성에 적합한 Li-K-Cd 합금을 제조하였으며, 이를 이용하여 U와 Nd가 포함된 LiCl-KCl 염에 투입하여 용 융염 내 UCl3의 제거가 가능한지 평가하였다.

Cu(II) can cause health problem for human being and phosphate is a key pollutant induces eutrophication in rivers and ponds. To remove of Cu(II) and phosphate from solution, chitosan as adsorbent was chosen and used as a form of hydrogel bead. Due to the chemical instability of hydrogel chitosan bead (HCB), the crosslinked HCB by glutaraldehyde (GA) was prepared (HCB-G). HCB-G maintained the spherical bead type at 1% HCl without a loss of chitosan. A variety of batch experiment tests were carried out to determine the removal efficiency (%), maximum uptake (Q, mg/g), and reaction rate. In the single presence of Cu(II) or phosphate, the removal efficiency was obtained to 17 and 16%, respectively. However, the removal efficiency of Cu(II) and phosphate was increased to 50~55% at a mixed solution. The maximum uptake (Q) for Cu(II) and phosphate was enhanced from 11.3 to74.4 mg/g and from 3.34 to 36.6 mg/g, respectively. While the reaction rate of Cu(II) and phosphate was almost finished within 24 and 6 h at single solution, it was not changed for Cu(II) but was retarded for phosphate at mixed solution.

As an approach for estimation of the droplet size in the molten salt-liquid metal extraction process, a droplet formation experiment at room temperature was conducted to evaluate the applicability of the Scheele-Meister model with water-mercury system as a surrogate that is similar to the molten salt-liquid metal system. In the experiment, droplets were formed through the nozzle and the droplet size was measured using a digital camera and image analysis software. As nozzles, commercially available needles with inner diameters (ID) of 0.018 cm and 0.025 cm and self-fabricated nozzles with 3-holes (ID: 0.0135 cm), 4-holes (ID: 0.0135 cm), and 2-holes (ID: 0.0148 cm) were used. The mercury penetration lengths in the nozzles were 1.3 cm for the needles and 0.5 cm for the self-fabricated nozzles. The droplets formed from each nozzle maintained stable spherical shape up to 20 cm below the nozzle. The droplet size measurements were within a 10% error range when compared to the Scheele-Meister model estimates. The experimental results show th

Current petrochemical product mainly comes from light olefin, such as ethylene and propylene. these olefins can be obtained as mixture form of olefin/paraffin, which is co-product of naphtha cracking process. However, the mixture of light olefin and paraffin is considerably difficult to separate because they have similar physicochemical properties such as density, boiling point, and molecular weight. Cryogenic distillation is currently utilized, but still suffered from high operating cost. Membrane separation with polyimide-based material is a promising alternative due to its lower energy cost and modular operation. Here, we synthesized composite membrane with metal-organic framework (MOF) based on polyimide exhibiting high permeability and selectivity in propylene/propane separation, as well as simple preparation and high stability.

This study investigated the effects of the post annealing temperatures on the electrical and interfacial properties of a metal-semiconductor-metal photodetector(MSM-PD) device. The interdigitate type MSM-PD devices had the structure Al(500 nm) / Ti(200 nm) / poly-Si(500 nm). Structural analyses of the MSM-PD devices were performed by employing X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscope(TEM). Electrical characteristics of the MSM-PD were also examined using current-voltage(I-V) measurements. The optimal post annealing condition for the Schottky contact of MSM-PD devices are 350℃-30minutes. However, as the annealing temperature and time are increased, electrical characteristics of MSM-PD device are degraded. Especially, for the annealing conditions of 400℃-180minutes and 500℃-30minutes, the I-V measurement itself was impossible. These results are closely related to the solid phase reactions at the interface of MSM-PD device, which result in the formation of intermetallic compounds such as Al3Ti and Ti7Al5Si12.

이산화탄소(CO2)는 천연 가스, 바이오 가스, 매립 가스의 성분으로 존재할 뿐만 아니라 화석연료의 주요 연소 생성물로써 온실 가스의 주범이다. 특히 내연기관의 연료 고효율을 얻고, 가스 수송시스템의 부식을 방지하며, 기후변화에 선제적으로 대응하기 위해서는 이산화탄소(CO2)의 저감 또는 제거 기술이 필수적이다. 지난 수십 년간, 멤브레인 기반 기술의 구성 및 설계 단순성에 의하여 관련 연구가 많이 이루어져 왔으며 많은 발전을 이루었다. 최근 들어, 기존 멤브레인 기반 분리 뿐만 아니라, 새로운 흡착제 기반 분리 기술 등에 대한 관심도 높아지고 있다. 특히, 최근 각광받고 있는 유기-금속 골격체 (Metal Organic Frameworks, MOFs)의 경우, 일반 다공질 흡착제와는 다른 독특한 성질(Flexibility, Gating effect 또는 Open Metal Sites 등)로 인하여, 이를 활용한 다양한 기체 분리 연구가 늘어나고 있는 추세이다. 따라서 본 연구에서는 대표적 플렉 서블한 물질인 MIL-53(Al)과 강한 결합에너지 site를 다수 보유한 대표적 MOF 물질인 MOF-74(Ni)를 활용하여 온도 및 압력에 따른 이산화탄소 메탄 분리 성능 비교 분석하였으며, 각 물질의 특성별 압력 및 온도에 따라 변화하는 적정 분리 구간을 제시하였다.

폴리락타이드 재질의 식품용 기구 및 용기·포장에서 식품으로 이행될 우려가 있는 유해 중금속인 납, 카드뮴 및 비소의 이행량을 측정하고 안전성을 평가하기 위하여 국내에 유통중인 폴리락타이드 시료 총 211건을 수거하였다. 용출실험은 ‘식품용 기구 및 용기·포장 공전’의 조건 에 따라 식품모사용매인 4% acetic acid로 하였으며 온도 조건으로 70oC와 가혹사용조건인 100oC 모두 적용하여 이 행량을 비교하였다. 납, 카드뮴 및 비소의 이행량은 모두 70oC보다 100oC의 조건에서 증가하는 경향을 보였으나, 납 의 최대 이행량은 기준·규격과 비교하여 1.0%의 낮은 수 준이었고, 카드뮴은 모두 미량이 검출되었으며, 비소의 최대 이행량은 기준·규격 대비 3.9%의 낮은 수준으로 기준·규격을 초과하는 시료는 없었다. 이행량 결과를 바탕으로 납, 카드뮴 및 비소의 일일추정섭취량을 산출한 후 잠정주간섭취허용량 등과 비교하는 안전성평가를 진행하였으며, 국내에 유통되는 식품용 폴리락타이드 기구 및 용기·포장을 통한 납, 카드뮴 및 비소의 일일추정섭취량은 2.5 × 10−5~ 2.0 × 10−3μg/kg bw/day인 것으로 산출되었다. 용출조건별로는 70oC, 30분에서 카드뮴의 일일추정섭취량이 가장 낮았고, 100oC, 30분에서의 납 일일추정섭취량이 2.0 × 10−3μg/kg bw/day로 제일 높게 나타났으나, 납의 위해도는 인체안전기준(25 μg/kg bw/week)과 비교시 0.055% 수준으로 매우 낮음을 확인되었다. 이를 통하여 국내 유통 폴리락타이드 재질 식품용 기구 및 용기·포장에서의 납, 카드뮴 및 비소의 이행량은 매우 낮은 수준임을 확인하였고, 본 연구의 결과는 향후 식품용 기구 및 용기· 포 장의 안전관리를 위한 과학적인 근거자료로 활용될 수 있을 것으로 사료된다.

Three kinds of STS304-Zr alloys were fabricated by varying the Zr content, and their microstructure and fracture properties were analyzed. Moreover, we performed heat treatment to improve their properties and studied their microstructure and fracture properties. The microstructure of the STS304-Zr alloys before and after the heat treatment process consisted of α-Fe and intermetallics: Zr(Cr, Ni, Fe)2 and Zr6Fe23. The volume fraction of the intermetallics increased with an increasing Zr content. The 11Zr specimen exhibited the lowest hardness and fine dimples and cleavage facets in a fractured surface. The 15Zr specimen had high hardness and fine cleavage facets. The 19Zr specimen had the highest hardness and large cleavage facets. After the heat treatment process, the intermetallics were spheroidized and their volume fraction increased. In addition, the specimens after the heat treatment process, the Laves phase (Zr(Cr, Ni, Fe) 2) decreased, the Zr6Fe23 phase increased and the Ni concentration in the intermetallics decreased. The hardness of all the specimens after the heat treatment process decreased because of the dislocations and residual stresses in α-Fe, and the fine lamellar shaped eutectic microstructures changed into large α-Fe and spheroidized intermetallics. The cleavage facet size increased because of the decomposition of the fine lamellarshaped eutectic microstructures and the increase in spheroidized intermetallics.

This study was carried out to investigate the presence of a correlation between heavy metals in urine samples and upper airway diseases. For the study, 51 household residents of Gwangyang, both with and without upper airway disease, were targeted. Urine samples were collected from the subjects along with a questionnaire from April 24th to 27th, 2017. The heavy metals in the urine samples were preprocessed and analyzed using an inductively coupled plasma/mass spectrometer. The geometric mean concentration of urinary arsenic and cadmium was 138.66 μg/L and 0.75 μg/g creatinine among those with upper airway disease and 166.42 μg/L and 1.19 μg/ g creatinine among those without upper airway disease. This was not a statistically significant difference. The concentration of urinary arsenic and cadmium was found to be increased by 1.19 times (95% CI; 0.15-9.31) and 1.26 times (95% CI; 0.31-5.04) in household residents with upper airway diseases with more than 144.86 μg/L and 0.85 μg/g creatinine, respectively.

자란만 퇴적물 중 유기물과 중금속의 농도분포와 오염현황을 파악하기 위하여 2014년 11월 15개 정점에서 표층 퇴적물을 채취하여 입도, 총유기탄소(TOC), 총질소(TN) 및 중금속(As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, Zn)을 분석하였다. 평균입도(Mz)는 8.6-9.8Ø(9.3±0.3Ø) 사이였으며, 니(Mud)와 점토(Clay)의 세립한 퇴적물로 구성되어 있었다. TOC와 TN은 각각 1.51-2.39%(1.74±0.22%), 0.20-0.33%(0.23±0.03%)의 범위로 전반적으로 공간적인 농도차이를 보이지 않았다. 모든 퇴적물에서 C/N 비 값은 5-10 사이를 보여 자란만 표층 퇴적물 중 유기물은 주로 해역 내에서 발생한 해양기원성 유기물인 것으로 파악되었다. 중금속 중 Cr, Fe, Mn은 만의 입구 쪽에서 높고 그 외 중금속(As, Cd, Cu, Hg, Pb, Zn)은 자란만의 안쪽에서 높은 농도를 보였다. 한편, 퇴적물 기준(SQGs), 농축계수(EF), 농집지수(Igeo), 오염부하량지수(PLI), 생태계위해도지수(ERI) 등 다양한 평가기법을 이용하여 자란만 표층 퇴적물의 중금속에 대한 오염정도를 살펴본 결과, Cd, Cr, Cu, Hg, Pb, Zn은 오염되지 않은 상태이거나 일부해역에서 오염된 상태를 보였지만 As는 전 해역에서 높은 오염도를 보였다. 또한, 분석된 모든 중금속 농도를 고려한 전체적인 오염도를 살펴본 결과, 모든 해역에서 중금속에 대하여 오염되었고 특히, 일부 해역에서는 저서생물에 위해성을 줄 수 있는 상태인 것으로 파악되었다. 따라서, 자란만 내 양식 수산물의 안전성 확보와 지속적인 어장 생산성 유지를 위해서 자란만 퇴적물 내 유기물과 중금속의 오염원에 대한 체계적인 관리가 필요하다.

연구는 자가제조퇴비를 사용하는 유기농가와 관행농 가로 구분하여 생산되는 배추와 토양의 위생지표세균(Aerobic plate count, coliform count, yeast & mold)과 식중독발병 가능성이 있는 유해미생물(Staphylococcus aureus, Environmental listeria, Bacillus cereus)의 밀도를 분석하였다. 그 결과, 토양과 식물체 모두 식품에서 위해균 허용한 계치인 5.0 Log CFU/g 이하로 검출되었다. 또한 토양에서 위해균 검출량과 식물체 표면의 위해균 검출량간의 상관 관계를 분석한 결과 정의 상관관계에 있었다. 또한 토양과 식물의 중금속 오염도를 조사한 결과 검출되지 않거나 허용한계치 이하로 검출되었다.

Objective of this study was to investigate the residual levels of heavy metals in rice contract farming complex for exporting to China. Paddy soil, irrigation water and rice grain were taken from 20 fie1ds located in Icheon city, Cheorwon-gun, Cheongju city, Seocheon-gun, Gunsan city and Haenamgun. The elements of samples were analyzed using ion chromatography, ICP-OES, and ICP-MS after acid digestion. The arsenic (As) contents of paddy soil were ranged from 2.9 to 18.2 mg/kg, which were lower than 25 mg/kg as concern level of environmental pollution in Korea. Cadmium (Cd) was below the limit of quantitation (0.006 mg/kg) in all samples. The highest contents of copper (Cu) was detected to be 25.6 mg/kg in Seocheon-gun sample, but it was below 1/10 fold of the threshold levels 250 mg/kg for soil pollution. Also, the average contents of nikel (Ni), lead (Pb), zinc (Zn), and hexavalent chrome (Cr6+) were found to be lower than the criterion of soil pollution concern, and it was considered to be safe. The residual levels of arsenic in agricultural waters were relatively high, up to 24.3 ug/L in river water, but was detected as 1~2 ug/L level in the ground water. These levels are lower than the water quality standard, 0.05 mg/kg of agricultural water. The concentrations of mercury (Hg) and total chromium (Cr) in the white rice and brown rice were less than the limit of quantitation, and the levels of cadmium in the range of 0.004 to 0.068 mg/kg were less than safety criteria 0.2 mg/kg in Korea and China. In addition, the contents of lead (Pb) in white rice ranged from 0.002 to 0.136 mg/kg, which was safe to be 0.2 mg/kg for Korean white rice and 0.2 mg/kg for China brown rice. As a whole, the residual levels of heavy metals such as arsenic in rice was safely maintained as 1/10 to 1/20 of the residual limits of Korea and China. In conclusion, the heavy metals levels should not be worried in rice contract farming complex for exporting to China.