본 연구에서는 한국 전통 과자인 유과와 강정을 원·부재료와 기기 및 도구, 작업자의 개인위생, 제조공정별 원료에 대한 미생물학적 오염을 분석하였다. 유과제조 과정 중 현장에서 사용하고 있는 세척 방법과 횟수에 따른 미생물 저감효과를 확인하고자 하였다. 강정의 제조 공정 중 튀밥에서 일반세균수 1.2 Log CFU/g, 완제품의 경우 3.7 Log CFU/g까지 점차 증가하였다. 유과의 제조 공정 중 일반세균수는 불림공정에서 일반세균 최대 6.5 Log CFU/g 수준으로 증가하다가 튀김공정에서 1.3 Log CFU/g수준으로 감소하였으나 완제품에서 4.0 Log CFU/g 수준으로 재오염되는 것으로 확인되었다. 이는 제조과정 중에 작업도구와 기기 또는 작업자 등에 의한 교차오염으로 판단되었다. 작업 도구인 주걱의 경우 일반세균 약 4.4 Log CFU/g, 대장균군 4.2 Log CFU/g으로 매우 오염도가 나타났다. 유과의 불림단계에서 7일동안 일반세균 수가 최대 10 Log CFU/g 이상, 대장균군의 경우 6.8 Log CFU/g으로 증가하였다. 손 또는 도구를 이용한 세척 방법과 흐르는 물에 세 척한 방법을 비교하였을 때, 손을 이용하여 수돗물로 10 회 세척하였을 때 일반세균 5.0 Log CFU/g, 대장균군 2.8 Log CFU/g 감소한 것으로 확인되었다. 이상의 결과로 볼 때, 소규모 업체의 전통 한과 제조 시 작업자나 작업 도 구 및 기기 사용 후 세척 및 소독하는 과정이 요구되며 완제품의 미생물 오염도를 감소시키기 위해 현장에 적용할 수 있는 저감화 방법이 필요한 것으로 판단되었다.

The effects of ammonia-treated graphene oxide (GO) on composites based on epoxy resin were investigated. Ammonia solutions of different concentrations (14–28%) were used to modify GO. Nitrogen functional groups were introduced on the GO surfaces without significant structural changes. The ammonia-treated GO-based epoxy composites exhibited interesting changes in their mechanical properties related to the presence of nitrogen functional groups, particularly amine (C-NH2) groups on the GO surfaces. The highest tensile and impact strength values were 42.1 MPa and 12.3 J/m, respectively, which were observed in an epoxy composite prepared with GO treated with a 28% ammonia solution. This improved tensile strength was 2.2 and 1.3 times higher than those of the neat epoxy and the non-treated GO-based epoxy composite, respectively. The amine groups on the GO ensure its participation in the cross-linking reaction of the epoxy resin under amine curing agent condition and enhance its interfacial bonding with the epoxy resin.

Activated carbon fiber (ACF) surfaces are modified using an electron beam under different aqueous solutions to improve the NO gas sensitivity of a gas sensor based on ACFs. The oxygen functional group on the ACF surface is changed, resulting in an increase of the number of non-carbonyl (-C-O-C-) groups from 32.5% for pristine ACFs to 39.53% and 41.75% for ACFs treated with hydrogen peroxide and potassium hydroxide solutions, respectively. We discover that the NO gas sensitivity of the gas sensor fabricated using the modified ACFs as an electrode material is increased, although the specific surface area of the ACFs is decreased because of the recovery of their crystal structure. This is attributed to the static electric interaction between NO gas and the non-carbonyl groups introduced onto the ACF surfaces.

Cellulose fibers were stabilized by treatment with an electron-beam (E-beam). The properties of the stabilized fibers were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The E-beam-stabilized cellulose fibers were carbonized in N2 gas at 800°C for 1 h, and their carbonization yields were measured. The structure of the cellulose fibers was determined to have changed to hemicellulose and cross-linked cellulose as a result of the E-beam stabilization. The hemicellulose decreased the initial decomposition temperature, and the cross-linked bonds increased the carbonization yield of the cellulose fibers. Increasing the absorbed E-beam dose to 1500 kGy increased the carbonization yield of the cellulose-based carbon fiber by 27.5% upon exposure compared to untreated cellulose fibers.

Carbon micro particles with dimple patterns were produced by electro-spraying a solution of pitch in tetrahydrofuran. Particle formation depended on separation in an electrical field and volatilization of the solvent. More than 80% of the obtained carbon exhibited an average particle size of less than 50 μm. X-ray diffraction analysis suggests that the carbon with dimple patterns has increased crystallinity after heat treatment.

Carbon fibers are prepared by stabilizing pitch fibers accompanying electron beam (E-beam) irradiation. The carbon fibers pretreated by E-beam irradiation achieve a higher stabilization index than the carbon fibers that are only heat-stabilized. In addition, the carbon fibers subjected to E-beam irradiation in the stabilization step exhibit a comparable tensile strength to that of general purpose carbon fibers. The carbon fibers pretreated with an absorbed dose of 3000 kGy have a tensile strength of 0.54 GPa for a similar fiber diameter. Elemental, Fourier-transform infrared spectroscopy, and thermogravimetric analyses indicate that Ebeam irradiation is an efficient oxidation and dehydrogenation treatment for pitch fibers by showing that the intensity of the aliphatic C–H stretching and aromatic CH2 bending (out-ofplane) bands significantly decrease and carbonyl and carboxylic groups form.

High crystallinity coke-based activated carbon (hc-AC) is prepared using a potassium hydroxide solution to adsorb carbon dioxide (CO2). The CO2 adsorption characteristics of the prepared hc-AC are investigated at different temperatures. The X-ray diffraction patterns indicate that pitch-based cokes prepared under high temperature and pressure have a high crystal structure. The textural properties of hc-AC indicate that it consists mainly of slit-like pores. Compared to other textural forms of AC that have higher pore volumes, this slit-poreshaped hc-AC exhibits higher CO2 adsorption due to the similar shape between its pores and CO2 molecules. Additionally, in these high-crystallinity cokes, the main factor affecting CO2 adsorption at lower temperature is the pore structure, whereas the presence of oxygen functional groups on the surface has a greater impact on CO2 adsorption at higher temperature.

An eco-friendly integrated multi-trophic aquaculture (IMTA) farming technique was developed with the goal of resolving eutrophication by excess feed and feces as fish-farming by-products. A variety of seaweed species were tried to remove inorganic nutrients produced by fish farming. However, there have been few trials to use Sargassum fulvellum in an IMTA system, a species with a relatively wide distribution across regions with various habitat conditions, great nutrient removal efficiency and importance for human food source and industrial purposes. In this regard, our study tried to examine feasibility of using S. fulvellum in an IMTA system by analyzing growth characteristics of the species in an IMTA system comprising of rockfish (Sebastes shlegeli), sea cucumber (Stichopus japonocus) and the tried S. fulvellum (October 2011 – November 2012). We also monitored environment conditions around the system including current speed, water temperature and inorganic nutrient level as they may affect growth of S. fulvellum. S. fulvellum in the IMTA system, which were 15.72±5.67 mm long at the start of the experiment in October 2011, grew to a maximum of 1093±271.13 mm by May 2012. In September, seaweed growth was reduced to a minimum of 280±70.43 mm in length. Then, S. fulvellum began to grow again reaching 325±196.19 mm by November 2012. Wet weight of the seaweed was 4.01±1.89 g at the start of the experiment and reached a maximum of 109.26±34.23 g in May. The weight gradually declined to a low of 15.12±8.40 g in September 2012. Weight began to increase once more, rising to 39.27±21.69 g by November. During the experiment, the average velocity at the surface and the bottom was 6.5 cm/s and 3.4 cm/s, respectively. The water temperature ranged 5.0-23.5℃, which was considered suitable for growing S. fulvellum. Results of the study indicated no significant differences in inorganic nutrients between pre- and post-IMTA installation. It was thus concluded that S. fulvellum can be a suitable seaweed species to be used in an IMTA system.

The purpose of this study is to analyze seasonal variations of seaweed community structure according to ocean environment at three areas in the east coast of Korea. Mean water temperatures of Gosung, Samchuk, and Gyeongju were 8.3℃, 11.2℃, and 13.1℃, respectively, during the growing winter season of 2011. Subtidal benthic macroalgal flora and community structure were investigated at the sites between February to November 2011. The numbers of seaweed species at the areas were 38, 12, and 15, respectively. The amounts of biomass were 7.35 kg m-2, 1.80 kg m-2, and 0.84 kg m-2, respectively, during the period. The values of C/P, R/P, and (R+C)/P representing flora characteristics at Sokcho area were 0.1, 1.1, and 1.2, respectively. The values of flora characteristics at Samchuk were 0.3, 0.6, and 1.0, respectively. The values of flora characteristics at Gyeongju were 0.4, 4.0, and 1.2, respectively

The recycled washwater, which has different water quality and is produced about 5 to 20% of the total water volume treated, affects the unit operation of water treatment, especially coagulation process. However, the effects of recycled washwater on unit operation of water treatment have not been fully investigated. In this study, effects of recycled washwater on coagulation process were investigated to find the optimum coagulation condition by analyzing turbidity, UV254, TOC removal efficiencies. In addition, effects of recycled washwater on residual Al after coagulation were studied by analyzing soluble and particulate Al. The size distribution and fractal dimension of coagulated also analyzed. The recycled washwater was lower pH than the raw water. And the recycled washwater had higher UV254, TOC and residual Al concentration than the raw water. Residual Al concentration of recycled washwater was about 50 times higher than that of raw water. Optimum coagulant dosages on the blending recycled washwater and the raw water for turbidity, UV254 and Al removal were lower than that on the raw water. However, TOC removal increased by increasing coagulant dosage. The size and fractal dimension of coagulated particle produced in the blending recycled washwater were larger, which imply faster settling velocity, than those produced in the raw water only.