Silica is used in shell materials to minimize oxidation and aggregation of nanoparticles. Particularly, porous silica has gained attention because of its performance in adsorption, catalysis, and medical applications. In this study, to investigate the effect of the density of the silica coating layer on the color of the pigment, we arbitrarily change the structure of a silica layer using an etchant. We use NaOH or NH4OH to etch the silica coating layer. First, we synthesize α-FeOOH for a length of 400 nm and coat it with TEOS to fabricate particles with a 50 nm coating layer. The coating thickness is then adjusted to 30–40 nm by etching the silica layer for 5 h. Four different shapes of α-FeOOH with different colors are measured using UV–vis light. From the color changes of the four different shapes of α-FeOOH features during coating or etching, the L* value is observed to increase and brighten the overall color, and the b* value increases to impart a clear yellow color to the pigment. The brightest yellow color was that coated with silica; if the sample is etched with NaOH or NH4OH, the b* value can be controlled to study the yellow colors.

Nitrogen-doped titanium dioxide (N-doped TiO2) is attracting continuously increasing attention as a material for environmental photocatalysis. The N-atoms can occupy both interstitial and substitutional positions in the solid, with some evidence of a preference for interstitial sites. In this study, N-doped TiO2 is prepared by the sol–gel method using NH4OH and NH4Cl as N ion doping agents, and the physical and photocatalytic properties with changes in the synthesis temperature and amount of agent are analyzed. The photocatalytic activities of the N-doped TiO2 samples are evaluated based on the decomposition of methylene blue (MB) under visible-light irradiation. The addition of 5 wt% NH4Cl produces the best physical properties. As per the UV-vis analysis results, the N-doped TiO2 exhibits a higher visible-light activity than the undoped TiO2. The wavelength of the N-doped TiO2 shifts to the visible-light region up to 412 nm. In addition, this sample shows MB removal of approximately 81%, with the whiteness increasing to +97 when the synthesis temperature is 600℃. The coloration and phase structure of the N-doped TiO2 are characterized in detail using UV-vis, CIE Lab color parameter measurements, and powder X-ray diffraction (XRD).

We synthesized potassium hexatitanate, (K2Ti6O13, PT6), with a non-fibrous shape, by acid leaching and subsequent thermal treatment of potassium tetratitanate (K2Ti4O9, PT4), with layered crystal structure. By controlling nucleation and growth of PT4 crystals, we obtained splinter-type crystals of PT6 with increased width and reduced thickness. The optimal holding temperature for the layered PT4 was found to be ~920 oC. The length and width of the PT4 crystals were increased when the nucleation and growth time were increased. After a proton exchange reaction using aqueous 0.3 M HCl solution, and subsequent heat treatment at 850 oC, the PT4 crystal transformed into splinter-type PT6 crystals. The frictional characteristics of the friction materials show that as the particle size of PT6 increases, the coefficient of friction (COF) and wear amounts of both the friction materials and counter disc increase.

배양시간(6, 12, 24, 48시간)에 따른 Yersinia enterocolitica 균체 및 배지 대사체들의 변화를 이해하기 위하여 GC/MS와 다변량통계분석을 이용하여 분석한 결과 Partial Least Squares-Discriminant Analysis(PLS-DA) scores plots 상에서 배양시간에 따라 분석 시료들이 뚜렷하게 분리되었다. 시료들 사이의 차이에 관여하는 대사물질들을 동정한 결과 균체에서는 ethylene glycol, valine, ethanolamine, succinic acid, adenine, stearic acid, 배지에서는 glycine, fumaric acid, threonine, aminomalonic acid, malic acid, glutamic acid, citric acid가 배양시간에 따른 차이가 나는 것으로 확인되었다. 이들 대사물질들을 이용하여 관련 대사경로를 도출한 결과 배양시기에 따라 에너지 생성에 관여하는 대사경로가 주로 변하는 것으로 관찰되었다. Y. enterocolitica의 경우 대수기 초기에는 TCA cycle을 통해 에너지를 공급하다가 정지기에 들어서면서 정상적인 TCA cycle를 수행하지 못하고 ethanolamine 및 ethylene glycol 등 다른 탄소원 또는 질소원을 공급하는 것으로 확인되었다. 비록 관련된 많은 연구가 필요함에도 불구하고 대사체분석 기술을 활용한 Y. enterocolitica 균체 및 배지 분석 연구는 배양시간에 따른 대사과정의 변화를 관찰할 수 있을 뿐만 아니라 향후 균체 연구의 다양한 분야에 접목될 수 있을 것으로 사료된다.

검역과정에서 선충검사는 묘목류, 구근류, 화본과 목초종자 및 근채류를 대상으로 하며, 식물검역의 선충검사는 일반적인 연구와 다른 몇가지 특징을 가진다. 첫째, 흙을 대상으로 하지 않는다. 둘째, 검출되는 선충의 밀도보다 규제대상 종 해당 여부가 중요하다. 셋째, 식물체를 대상으로 하는 검사의 특성상 식물체의 즙액 등이 시간이 지나면서 부패하여 물속의 산소를 소모하므로 선충이 사멸되어 선충분리가 되지 않는 경우가 많다. 넷째, 시료의 사용량이 매우 많다. 다섯째, 연중무휴 선충분리검사를 실시한다. 농업현장에서는 선충검사가 농업작기에 따라 진행되지만 식물검역은 연중무휴 이루어지므로 여름철 고온기와 겨울철 저온기의 검사장소의 환경 조성에 유의하여야 한다. 여섯째, 한 속에서 여러 종이 동시에 검출되어 종 동정이 어렵다. 식물검역과정에서 2006년 이후 한국의 식물검역에서 매년 평균 300여회 이상 식물기생선충이 검출되는데, 그중에 7~80% 이상은 뿌리썩이선충과 뿌리혹선충으로 종 동정률이 매우 낮아 분자생물학적인 종 동정법을 모색하고 있다.

사탕무씨스트선충 박멸프로그램 시범사업 포장(태백시 원동)에 활용할 방제효 과 확인용 씨스트선충을 투입하기 위해 태백시, 삼척시, 정선시에 사탕무씨스트선 충이 감염된 배추포장에서 토양을 채집하여 씨스트선충을 분리하였다. 분리한 씨 스트선충을 바이알병에 넣고, 모래를 채운 후 솜으로 입구를 막았다. 씨스트선충이 들어있는 바이알병을 방제구 깊이에 맞춘 씨스트선충 투입용 파이프에 모래를 채 우며 10㎝간격으로 넣었다. 이 파이프는 바이알병 및 모래가 유출되지 않도록 천을 이용하여 밀봉조치후 방제구내에 투입하였다. 투입된 씨스트선충 방제효과 검정 은 배추 포트 재배 하여 씨스트선충 부착 여부를 확인하는 방법인 점밀검정과 씨스 트선충을 염색하여 알의 활력을 확인하는 방법인 씨스트선충활력검정(생물활성 검정)이 있다. 생물활성검정은 정밀검정보다 효율적이며, 시간이 단축되고, 비교 적 간단한 방법이다. 방제효과를 검정하기 위해 예비실험으로 살아있는 씨스트선 충과 열처리한 씨스트선충을 생물활성검정을 통해 비교하고자 하였다.

계류돌핀의 강관말뚝식 하부구조에 대한 실용적 설계최적화 과정을 제시하고, 수치 예를 통하여 유용성을 평가하였다. 유한차원 최적설계 문제의 정식화에서, 말뚝들을 몇 개의 그룹으로 구분하여 이들의 기하학적 위상과 단면의 치수를 설계변수로 활용하였다. 설계목적함수는 말뚝의 총 중량이며, 설계제약조건은 응력과 근입 깊이, 설계변수의 상한과 하한 등이다. 설계변수의 연계와 고정을 통해 몇 가지의 실용적 설계 대안을 검토하였다. 최적화 프로그램으로는, 순차2차계획법(SQP)을 사용하고 또 쉽게 얻을 수 있는 PLBA 및 IMSL 라이브러리의 DNCONF서브루틴을 이용하였다. 수치예제의 돌핀은 20개의 강관말뚝으로 하부구조를 형성하며, 이중 4개는 연직말뚝이고 16개는 경사말뚝이다. 다양한 대안 설계에서 성공적으로 최적해를 얻었으며, 실용적인 최적 설계과정 임을 확인할 수 있었다.

To develop a new fish cage which is required for offshore or moving cage culturing system has been gradually increased against being closely dense of fish cage in shallow water. Though submersible fish cage culturing system is essential technology for converting from shallow water into the offshore, it was pointed out the serious problem about stability of which are sinking and floating state. This study is presented conceptual design of submersible fish cage centered with a mooring steel pile to acquire stability and faculty. Design of mooring steel pile for submersible fish cage culturing system needs to carry out optimal design of mooring steel pile for which much efforts are required. Formulation and optimal design process of submersible fish cage are organized into using Sequential Quadratic Programming method of numerical optimization. For submersible fish cage system centered with a mooring steel pile, process of the optimal design is proposed and the optimal solutions are obtained

The preaent study was conducted to investigate the effect of mixed seeding of three wheat variwties, ‘Anzunbaengimil’, ‘Jokyoung’, and ‘Sooan’, on agricultural characteristics and quality of plants to select the most suitable mixed seeding ratio. We observed that the yield of plants obtained from the mixed seeding combinations was higher than those obtained from single seeding of the three varieties. The yield was high, especially for the combinations ‘Sooan’ and ‘Anzunbaengimil’ (80 and 20%, respectively) and ‘Sooan’ and ‘Jokyoung’ (90 and 10%, respectively). The protein content of the seedlings obtained from the above two combinations was higher than in the seedling of ‘Sooan’. Based on our results, we suggest that mixed seeding of wheat varieties is more effective than single seeding in improving the yield and quality of plants obtained from mixed seeding.

We investigated the optimal conditions for keratinase production by feather-degrading Pseudomonas geniculata H10 using one variable at a time (OVT) method. The optimal medium composition and cultural condition for keratinase production were determined to be glucose 0.15% (w/v), beef extract 0.08% (w/v), KH2PO4 0.12% (w/v), K2HPO4 0.02% (w/v), NaCl 0.07% (w/v), MgSO4․7H2O 0.03%, MgCl2․6H2O 0.04% along with initial pH 10 at 200 rpm and 25℃, respectively. The production yield of keratinase was 31.6 U/ml in an optimal condition, showing 4.6-fold higher than that in basal medium. The strain H10 also showed plant growth promoting activities. This strain had ammonification activity and produced indoleacetic acid (IAA), siderophore and a variety of hydrolytic enzymes such as protease, lipase and chitinase. Therefore, this study showed that P. geniculata H10 could be not only used to upgrade the nutritional value of feather wastes but also useful in situ biodegradation of feather wastes. Moreover, it is also a potential candidate for the development of biofertilizing agent applicable to crop plant soil.

Although antioxidant activities of Korean traditional fermented foods were reported by many researchers, study on antioxidant activity of microorganism originated from Korean traditional fermented foods was little. Therefore, we improved condition for antioxidant production by a bacterium isolated from home-made Chungkookjang. We selected a bacterial strain, which showed the highest antioxidative activity, from Chungkookjang and then named GJ. The selected GJ strain was identified as Bacillus methylotrophicus by alignment data of 16S rRNA gene nucleotide sequences. Improved medium compositions for DPPH radical scavenging activity were 0.25% sucrose, 1% peptone, 0.01% MgSO4·7H2O and initial pH 6.5, respectively. Optimal culture conditions were 30℃, 200 rpm and 4% inoculum volume, respectively. In improved conditions, DPPH radical scavenging activity of GJ reached to 91% in a short time. The strain GJ also possessed ACE inhibition and other antioxidative activities; ACE inhibition activity (49.4%), ABTS radical scavenging activity (99.8%), metal chelating activity (67.9%), SOD-like activity (36.5%) and reducing power (A700 = 5.982) were observed, respectively. Therefore, our results suggest that B. methylotrophicus GJ strain may be potential candidate for functional foods, cosmetic products for anti-aging and medicine for diseases caused by oxidative stress.

This study was carried out to investigate changes of protease and amylase activities and nitrogen content in Chungkookjang prepared by Bacillus subtilis S8 and different soybean. Amino-type nitrogen and ammonia-type nitrogen contents increased with an increase in fermentation time and was the highest in black soybean Chungkookjang. The number of viable cells increased up to 24 h of fermentation at all temperatures tested; especially, their levels were the highest at 40℃. Protease activity was the highest in black soybean Chungkookjang. α-amylase activity increased significantly up to 6 h of fermentation at 30℃and 40℃and then maintained constantly. It also increased up to 30-36 h of fermentation at 45℃and then decreased. β -amylase activity was the highest in black soybean Chungkookjang at 35℃and 40℃and in yellow soybean Chungkookjang at 45℃. Production pattern of reducing sugar was similar to that of β-amylase. Amino-type nitrogen, viable cell number and reducing sugar content and β-amylase activity was the highest in Chungkookjang fermented at 40℃. Considering amino-type and ammonia-type nitrogen contents, Chungkookjang fermentation using yellow soybean was favorable. However, the fermentation using black soybean was favorable, considering protease and amylase activities and reducing sugar content.

We investigated usefulness of chicken feather as bioadsorbent for removal of hexavalent chromium[Cr(Ⅵ)] and oil from aqueous solution. Chicken feather was chemically treated with DTPA, EDTA, NaOH and SDS, respectively. Among them, EDTA was the most effective in adsorbing Cr(Ⅵ). Cr(Ⅵ) uptake by chicken feather was increased with decreasing pH; the highest Cr(Ⅵ) uptake was observed at pH 2.0. By increasing Cr(Ⅵ) concentration, Cr(Ⅵ) uptake was increased, and maximum Cr(Ⅵ) uptake was 0.34 mmol/g. Cr(Ⅵ) adsorption by chicken feather was well described by Freundlich isotherm than Langmuir isotherm and Freundlich constant(1/n) was 0.476. As the concentration of chicken feather was increased, Cr (Ⅵ) removal efficiency was increased but Cr(Ⅵ) uptake was decreased. Most of Cr(Ⅵ) was adsorbed at early reaction stage(1 h) and adsorption equilibrium was established at 5 h. On the other hand, chicken feather adsorbed effectively oils including bunker-A and bunker-C. In conclusion, our results suggest that chicken feather waste could be used to remove heavy metal and oil; it is a potential candidate for biosorption material.

We isolated and characterized novel duck feather-degrading bacteria producing keratinase. Twelve strains were isolated from soil and faces at poultry farm, and decayed feathers. They were identified as Bacillus methylotrophicus, Pseudomonas geniculata, Pseudomonas hibiscicola, Exiquobacterium profundum, Bacillus pumilus, Bacillus amyloliquefaciens, Chryseobacterium indologenes, Bacillus thuringiensis, Thermomonas koreensis, respectively, by phenotypic characters and 16S rRNA gene analysis. Generally, the level of keratinase production was not proportional to feather degradation rate. The highest keratinolytic activity was observed in the culture inoculated with Chryseobacterium indologenes D27. Although all strains did not degrade human hair, strains tested effectively degraded chicken feather(53.8-91.4%), wool(40.4-93.0%) and human nail (51.0-82.9%). These results suggest that strains isolated could be not only used to improve the nutritional value of recalcitrant feather waste but also is a potential candidate for biotechnological processes of keratin hydrolysis.