Recently, separation membranes have been applied to fields such as water supply, sewage treatment, gray water reuse, and air pollution control. Chemical cleaning technology is attracting attention among the methods of reusing these expensive separation membranes. It was found that the separation membrane could be regenerated using chemical cleaning. Specifically, it was found that the use time of the separation membranes regenerated by chemical cleaning was sustainable for more than 1,700 hours. Additionally, it was found that the flux recovery ratio after chemical cleaning was maintained at least 60%. In addition, the flux recovery ratio of HYDREX 4710, an organic membrane cleaner, and 4703, an inorganic membrane cleaner, was 76% and 62%, respectively, showing the highest flux recovery ratio among the chemicals used. Considering that the target raw water of this study is biological secondary treatment water, it was suggested that chemical cleaning could be actively used to regenerate separation membranes in future water treatment.

The disposal of spent nuclear fuel (SNF) in a deep geological repository (DGR) is a widely accepted strategy for the long-term sequestration of radiotoxic SNF. Ensuring the safety of a DGR requires the prediction of various reactions and migration behaviors of radionuclides (RNs) present in SNF within its geochemical surroundings. Understanding the dissolution behaviors of mineral phases harboring these RNs is crucial, as the levels of RNs in groundwater are basically linked to the solubility of these solid phases. Accurate measurements of solubility demand the use of welldefined solid materials characterized by chemical compositions and structures. Herein, we attempted the synthesis of sklodowskite, a magnesium-uranyl (U(VI))-silicate, employing a twostep hydrothermal synthetic approach documented previously. Subsequently, we subjected this synthesized sklodowskite to various analytical techniques, including powder X-ray diffraction (pXRD), scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDX), and vibrational spectroscopies (FTIR and Raman). Based on our findings, we confidently identify the obtained mineral phase as sklodowskite (Mg[UO2SiO3OH]2·5H2O). This identification is primarily based on the similarity between its pXRD pattern and the reference XRD pattern of sklodowskite. Furthermore, the measured infrared and Raman spectra show the vibrational modes of UO2 2+ and SiO4 4- ions, particularly within the 700~1,100 cm-1 region, which support that the synthetic mineral has a characteristic layered uranyl-silicate structure of crystalline sklodowskite. Finally, we utilized synthetic minerals to estimate its solubility up to about three months in a model groundwater, where the dissolved species composition is analogous to that of granitic groundwater from the KAERI Underground Research Tunnel. In this presentation, we will present in detail the results of spectroscopic characterizations and the methodology employed to assess the solubility of the U(VI)-silicate solid phase.

본 연구는 패류 독소 중 기억상실성 독성을 유발하는 domoic acid의 분석법 개선, 검증 및 분석적용성을 살펴보 았다. SAX 카트리지 정제, 검체 및 추출용매 양의 변경 과 더불어 이동상을 용매구매 조건으로 변경시킨 분석법 은 지중해담치, 홍게 그리고 멸치의 세 가지 매트릭스를 대상으로 세 농도에 대하여 식품공전법과 비교하여 유효 성을 검증하였다. 그 결과 변경된 분석법은 LOD 0.02-0.03 mg/kg, LOQ 0.05-0.09 mg/kg, 일내 및 일간 정확도 86.2- 100.4%와 일내 및 일간 정밀도 0.2-4.0%로 CODEX가이 드라인을 만족하는 우수한 분석능을 나타내었다. 특히 변 경된 시험법에서는 domoic acid와 유사한 머무름 시간을 갖는 방해물질이 검출되지 않아 위양성 결과를 방지할 수 있을 것으로 생각된다. 더 나아가 본 분석법이 국내 유통 중인 수산물을 대상으로 적용될 수 있는지 확인하고자 식 품공전의 기억상실성 패독 분석법과 함께 수산물에 적용 하여 분석하였다. 그 결과 5종의 수산물 87건 중 공전시 험법으로 분석했을 때 domoic acid가 검출된 시료는 없었 으나 변경된 분석법을 통하여 멸치 1건에 대하여 0.14 mg/ kg의 domoic acid이 미량 검출되었다. 따라서 본 연구에 서 확립된 분석법은 수산물 중 domoic acid 분석에 활용 이 가능할 것으로 보인다.

A solid-phase competition enzyme-linked immunosorbent assay (ELISA), recombinant VP2 (rVP2) protein, and monoclonal antibody (mAb) were developed for the specific and sensitive detection of porcine parvovirus (PPV) antibodies in pig sera. A total of 1,544 sera samples were collected from breeding pig farms located in the Gyeongsangbuk-do Province in the Republic of Korea. The optimal operating conditions of SC-ELISA were as follows. The concentration of rVP2 proteins coated on the wells was 4 μg/mL, the swine sera were diluted 1:2, and the HRP-conjugated PPV VP2 mAb (9A8 clone) was used at 500 ng/mL. These results suggest that the SC-rVP-ELISA assay may be a valuable alternative to the current diagnostic tools used to detect PPV-specific monoclonal antibodies and broadly monitor PPV infections in domestic pigs at different breeding stages.

The aim of this study was to evaluate pretreatment methods for 27 pharmaceuticals and personal care products (PPCPs) in various sewage samples using a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) and online solid-phase extraction with LC-MS/MS. Extraction efficiencies of PPCPs in the solid phase under different experimental conditions were evaluated, showing that the highest recoveries were obtained with the addition of sodium sulfate and ethylenediaminetetraacetic acid disodium salt dehydrate in acidified conditions. The recoveries of target compounds ranged from 91 to 117.2% for liquid samples and from 61.3 to 137.2% for solid samples, with a good precision. The methods under development were applied to sewage samples collected in two sewage treatment plants (STPs) to determine PPCPs in liquid and solid phases. Out of 27 PPCPs, more than 19 compounds were detected in liquid samples (i.e., influent and effluent) of two STPs, with concentration ranges of LOQ-33,152 ng/L in influents and LOQ-4,523 ng/L in effluents, respectively. In addition, some PPCPs such as acetylsalicylic acid, ibuprofen, and ofloxacin were detected at high concentrations in activated sludge as well as in excess sludge. This methodology was successfully applied to sewage samples for the determination of the target compounds in STPs.

본 연구에서는 이수의 유동 특성을 분석하기 위한 기초 연구로서 상용 코드인 ANSYS CFX 14.5를 이용하여 고체-액체 2상 유동 에 대한 수치해석적 연구를 수행하였다. 고체-액체 2상 유동 현상을 모사하기 위해서 균질류 모델과 분리류 모델을 사용하였다. 분리류 모델에서는 Gidaspow의 항력모델을 적용하였으며, 고체 입자에 운동 이론 모델을 적용하였다. 기존의 실험 결과를 기반으로 본 연구에서 사용한 수치해석 모델의 유효성을 검토하였으며, 수치해석은 직경 54.9 mm, 길이 3 m의 수평관에서 체적 분율 0.1~0.5, 속도 1~5 m/s 범위에서 수행되었다. 그리고 압력강하와 고체 입자의 체적 분율 분포를 확인하였으며, 압력강하는 균질류 모델과 분리류 모델이 각각 MAE 17.04%, 8.98 % 이내에서 실험결과를 잘 예측하였다. 관의 하부에서 높은 체적 분율이 나타나며, 상부로 갈수록 체적 분율은 감소하였다. 그리고 속도가 증가할수록 높이 변화에 따른 체적 분율 분포의 변화는 감소하였으며, 수치해석 결과는 이러한 유동 특성을 잘 예측하였다.

발아대두 동충하초의 유산균 발효를 위하여 발아대두와 동충하초가 함유된 배지에서 생육이 우수한 유산균주를 김치로부터 분리하여 동정한 결과 Lactobacillus plantarum KCB001로 명명하였다. 선정된 유산균을 이용하여 발아대두 동충하초의 고상발효조건을 최적화한 결과, 동충하초와 발아대두의 혼합비는 4:1, 가수량은 40%(v/v), 종배양액의 첨가량은 20%(v/w), 최적 발효온도와 시간은 각각 37oC와 72시간으로 확인되었다. 유산균발효에 의해 총 폴리페놀함 량과 DPPH 소거능이 증가하였으며, 특히 동충하초의 지표 물질인 cordycepin 함량은 발효에 의해 24% 증가함으로써 발효에 의해 발아대두 동충하초의 기능성이 증가함을 확인하였다.

With continuous development in the field of sample preparation technology, solid phase micro-extraction (SPME) has been widely used in analytical chemistry for high extraction efficiency and convenient operation. Different materials lead to different extraction results. Among existing materials, carbon-based materials are still attracting attention from scientists due to their excellent physical and chemical properties as well as their modifiable surfaces, which could enhance the adsorption effects of SPME fiber. This review introduces the preparation methods and applications of different kinds of carbon-based material coatings on fibers. In addition, directions for future research on carbon material composites are discussed.

This study investigated the chemical composition of headspace gas from white-flowered lotus (Nelumbo nucifera Gaertner). Volatile flavor compositions of headspace from white-flowered lotus (floral leaf, stamen, flower stalk, stem) were investigated through the solid-phase microextraction method using polydimethylsiloxane-divinylbenzene fiber. The headspace was directly transferred to a gas chromatography-mass spectrometry. Sixty-three volatile flavor constituents were detected in the headspace of lotus floral leaves, and undecanoic acid (7.81%) was the most abundant component. Fifty-three volatile flavor constituents were detected in the headspace of lotus stamina, and isobutylidene phthalide (7.94%) was the most abundant component. Forty-four volatile flavor constituents were detected in the headspace of lotus flower stalks, and 3-butyl dihydrophthalide (11.23%) was the most abundant component. Fifty-nine volatile flavor constituents were detected in the headspace of lotus stems, and ligustilide (16.15%) was the most abundant component. The content of phthalides was higher in the headspace of flower stalks and stems, while alcohols and acids were the predominant compounds in lotus floral leaves.

The objective of this study was to identify the main floral scents and their relative contents in the floral organ of Nelumbo nucifera. N. nucifera flower, a traditional Chinese medicinal herb, is rich in volatile compounds. In this study, the volatile components of N. nucifera flowers were investigated by headspace solid-phase microextraction gas chromatography-mass spectrometry for each organ of the flower: petals, sepals, pistils, and stamens. In total, we identified 39 compounds, among which aliphatics were major constituents, representing more than 94% of petals and sepals volatiles, followed by sesquiterpenes representing more than 69% of pistils and stamens volatiles. Pentadecane, 1-pentadecene, 8-hexadecyne, 8-heptadecene, and β-caryophyllene characterize the scent of the N. nucifera flower. We identified 24 volatiles in petals and sepals, 25 volatiles in pistils, and 18 volatiles in stamens. Among the monoterpenes, 3-Isopropylidene-4-methylcyclohexene, isoterpinolene, p-Menth-2-en-7-ol, and methyl 2,6,6- trimethylcyclohex-1-enecarboxylate were analyzed and identified for the first time from the N. nucifera flower. This study demonstrates that N. nucifera flowers differ greatly in volatile composition depending on the floral organ of the plant.

In order to examine how the solid-liquid interface responds to temperature variation depending on the materials characteristics, i.e. faceted phase or nonfaceted phase, the moving solid-liquid interface of transparent organic material, as a model substance for metallic materials (pivalic acid, camphene, salol, and camphor-50wt% naphthalene) was observed in-situ. Plots of the interface movement distance against time were obtained. The solid-liquid interface of the nonfaceted phase is atomically rough; it migrates in continuous mode, giving smooth curves of the distance-time plot. This is the case for pivalic acid and camphene. It was expected that the faceted phases would show different types of curves of the distance-time plot because of the atomically smooth solid-liquid interface. However, salol (faceted phase) shows a curve of the distance-time plot as smooth as that of the nonfaceted phases. This indicates that the solid-liquid interface of salol migrates as continuously as that of the nonfaceted phases. This is in contrast with the case of naphthalene, one of the faceted phases, for which the solidliquid interface migrates in “stop and go” mode, giving a stepwise curve of the distance-time plot.

본 논문은 육해상의 운송장치에 축냉시스템을 적용시키기 위한 기초 연구이다. 또한, 축냉재의 고액상변화에 대한 수치해석을 수행한 연구이다. 수치해석법으로는 유한차분법(Finite-Difference Method)을 이용하였으며, 1차원 비정상의 상태를 가정하여 계산하였다. 또한 용기는 직사각형의 구형용기로 가정하여 대칭의 조건을 이용하였다. 축냉을 목적으로 사용하는 열매체는 염화칼슘 수용액(CaCl₂) 30wt%의 물성치를 사용하여 계산을 수행하였다. 계산에 영향을 미치는 요소로는 냉동고의 냉기 온도 및 냉기 유속이 있으며, 축냉재를 싸고 있는 용기는 플라스틱으로 가정하였다. 본 수치해석에서 경계층의 두께는 냉기의 속도 증가와 함께 얇게 되고 축열시간도 짧아지는 것을 확인할 수 있었다. 그리고 냉기의 유속이 빨라질수록 열전달이 촉진되어 축냉용기 전면부에서의 온도가 낮아짐을 알았다. 축냉용기의 후면부에서는 경계층이 두꺼워져 열전달이 전면부에 비해 작아짐을 알았다.

MgB2 bulk superconductors are synthesized by the solid state reaction of (MgB4+xMg) precursors withexcessive Mg compositions (x=1.0, 1.4, 2.0 and 2.4). The MgB4 precursors are synthesized using (Mg+B) powders. Thesecondary phases (MgB4 and MgO) present in the synthesized MgB4 are removed by HNO3 leaching. It is found thatthe formation reaction of MgB2 is accelerated when Mg excessive compositions are used. The magnetization curves ofMg1+xB2 samples show that the transition from the normal state to the superconducting state of the Mg excessive sam-ples with x=0.5 and x=0.7 are sharper than that of MgB2. The highest Jc-B curve at 5 K and 20 K is achieved forx=0.5. Further addition of Mg decreases the Jc owing to the formation of more pores in the MgB2 matrix and smallervolume fraction of MgB2.

As the demand for large-scale analysis of gene expres- sion using DNA arrays increases, the importance of the surface characterization of DNA arrays has emerged. We com- pared the efficiency of molecular biological applications on solid-phases with different surface polarities to identify the most optimal conditions. We employed thiol-gold reactions for DNA immobilization on solid surfaces. The surface polarity was controlled by creating a self-assembled monolayer (SAM) of mercaptohexanol or hepthanethiol, which create hydrop- hilic or hydrophobic surface properties, respectively. A hyd- rophilic environment was found to be much more favorable to solid-phase molecular biological manipulations. A SAM of mercaptoethanol had the highest affinity to DNA mole- cules in our experimetns and it showed greater efficiency in terms of DNA hybridization and polymerization. The opti- mal DNA concentration for immobilization was found to be 0.5 mM. The optimal reaction time for both thiolated DNA and matrix molecules was 10 min and for the polymerase reaction time was 150 min. Under these optimized condi- tions, molecular biology techniques including DNA hybri- dization, ligation, polymerization, PCR and multiplex PCR were shown to be feasible in solid-state conditions. We de-monstrated from our present analysis the importance of surface polarity in solid-phase molecular biological appli- cations. A hydrophilic SAM generated a far more favorable envi- ronment than hydrophobic SAM for solid‐state molecular techniques. Our findings suggest that the conditions and met- hods identified here could be used for DNA‐DNA hybri- dization applications such as DNA chips and for the further development of solid-phase genetic engineering applicatio- ns that involve DNA-enzyme interactions.

According to kinetic mechanisms, liquid phase polymerization and solid phase polymerization are different in acrylonitrile (AN) polymerization, and so the relationship between the contribution ratio and molecular weight distribution (MWD) was obtained through theoretic analysis. The precipitation homopolymerization of AN was carried out in a mixture solution of dimethyl sulfoxide (DMSO) and water at 50~65℃ using α,α'-azobisisobutyronitrile as an initiator. The contribution ratio decreased and approached 0; the MWD also decreased and approached 2 with the increase of the H2O/DMSO ratio from 10/90 to 90/10. The experimental data were found to coincide well with the theoretical equation derived from the mechanisms.

HS-SPME법을 이용하여 한국 서남해 연안해역에서 Sea-nine 211, Irgarol 1051, Diuron과 같은 방오제의 분포 특성을 검토하였다. 반감기가 짧은 Sea-nine 211은 모든 시료채취지점 및 지역의 해수와 퇴적물에서 아주 낮은 농도 또는 검출한계 이하로 분포하였다. Irgarol 1051은 해수 및 퇴적물에서의 최고 농도가 각각 6.98μg/L, 28.50 ng/g-dry wt로 검출되었으며, 지역별 분포 특성은 나타나지 않았다. 반감기가 가장 길고 생물 농축성이 강한 Diuron은 모든 시료채취 지점에서 Sea-nine 211과 Irgarol 1051보다 높은 농도로 분포하였으며, Mo7(목포)의 퇴적물에서 최고농도(3882.22 ng/g-dry wt)로 분석되었다. Irgarol 1051과 Diuron은 조선산업단지 및 선박정박지가 위치하고 있는 지점에서 높은 농도로 분포하는 것으로 나타났다. 또한 퇴적물에서의 방오제 분포는 내만에서 외만으로 그 농도가 낮아졌다. 이러한 결과로부터 방오제는 내만에 위치하고 있는 항구나 조선산업단지로부터 오염될 가능성이 높을 것으로 판단된다.

The methods for determining the diffusion parameters for the diffusion of d-limonene, a major volatile compound of orange juice, through a multi-layered food packaging material and predicting its absorption into the packaging material have been investigated. The packaging material used was the 1.5-mm thick multi-layered packaging material composed of high impact polystyrene (HIPS), polyvinylidene chloride (PVDC), and low density polyethylene (LDPE). Orange juice was placed in a cell where volatiles were absorbed in the sample package and kept at 23±2oC for 72 hr. The d-limonene absorbed in a 1.5-mm thick multi-layered food packaging material was analyzed by a solid phase micro-extraction (SPME). The absorption parameters for the absorption of d-limonene in the packaging material were determined and absorption of d-limonene into the packaging material was predicted using absorption storage data. The SPME desorption at 60oC for 1 hr resulted in the most sensitive and reproducible results. The diffusion coefficients of d-limonene in the packaging material and the partition coefficient at 23±2oC were approximately 1-2×10-12m2/s and 0.03, respectively. The absorption profile no earlier than 30 hr was fit well by a model derived from the Fick’s law.