In this study, a micro gas sensor for NOx was fabricated using a microelectromechanical system (MEMS) technology and sol-gel process. The membrane and micro heater of the sensor platform were fabricated by a standard MEMS and CMOS technology with minor changes. The sensing electrode and micro heater were designed to have a co-planar structure with a Pt thin film layer. The size of the gas sensor device was about 2mm×2mm. Indium oxide as a sensing material for the NOx gas was synthesized by a sol-gel process. The particle size of synthesized In2O3 was identified as about 50 nm by field emission scanning electron microscopy (FE-SEM). The maximum gas sensitivity of indium oxide, as measured in terms of the relative resistance (Rs=Rgas/Rair), occurred at 300˚C with a value of 8.0 at 1 ppm NO2 gas. The response and recovery times were within 60 seconds and 2 min, respectively. The sensing properties of the NO2 gas showed good linear behavior with an increase of gas concentration. This study confirms that a MEMS-based gas sensor is a potential candidate as an automobile gas sensor with many advantages: small dimension, high sensitivity, short response time and low power consumption.

피부 노화를 방지하고 지속적으로 보습을 유지하기 위해 다양한 베시클들이 연구되고 있다. 최근에 활성물질의 흡수, 투과 및 보습의 유지와 관련하여 리포좀, 액정 및 다중층 라멜라 에멀젼 같은 많은 제조 방법들이 소개되고 있다. 본 연구에서는 인지질과 유사한 cetearyl alcohol/ceteth-20 phosphate/dicetyl phosphate 계면활성제를 이용하여 전단세기 및 pH 변화에 따른 다중층 라멜라 베시클을 개발하였으며 편광현미경을 통해 확인하였다. 결과로서 낮은 전단세기 및 pH에서는 라멜라 베시클 입자의 형태가 불균일하게 형성됨을 확인하였다. 42℃에서 2개월 간의 라멜라 베시클 내의 레티놀 함량의 변화를 측정한 결과 낮은 pH에서 레티놀의 함량이 감소하였다. 또한, 이 라멜라 베시클은 일반 O/W 에멀젼에 비해 피부 수분손실량이 14% 감소됨을 확인하였으며, O/W 썬 크림과 내수성 in vitro SPF를 측정하여 비교한 결과 UVB와 UVA 영역 모두에서 자외선을 잘 차단하여 유사한 내수성을 보이고 있음을 확인하였다.

무지개 빛을 내는 무기진주광택안료는, 내광성, 내용제성 및 내열성 등이 물리적 화학적 안정성이 우수하여 다양한 분야에서 응용되고 있다. 본 연구는 수열합성방법을 사용하여 마이카 티타니아에 파란색 코팅 안료인 염화코발트를 기본으로 화장품 안료로 사용되는 진주광택안료를 합성하였다. 코발트에 의한 안료의 색상을 보완하고자 코발트와 금속 염의 비를 달리하여 안료를 코팅하고, 이를 통해 금속염의 종류에 따라 다양한 색차값을 구현하는 진주광택 안료를 합성하였다. 코발트와 첨가된 금속 염 전구체의 조성비와, 금속 염의 종류에 따라 코팅 특성과 색상을 조절할 수 있었고, 안료의 다양한 색상변화 특성을 색차계를 통해 확인 하였다. 합성된 안료는 SPM, SEM, XRD, EDS 기기를 통해 특성을 분석하였다.

This study was performed to evaluate the quality characteristics of sourdough bread with addition of lactic acid bacteria (LAB) in the antibacterial activity. The starter cultures were used for sourdough bread to increase bread shelf-life: Lactobacillus fermentum, Lactobacillus paracasei KB28, and Pediococcus pentosaceus MJK7. The results showed that the viable counts of lactic acid bacteria were increased in 8.1~9.2 log cfu/㎖, respectively. The pH of the three sourdoughs was lower than that of control. In the texture characteristics, hardness, gumminess, and chewiness were tended to increase on the sourdough bread. Among the three sourdough breads, bread volume and retrogradation of bread were not significantly different. According to the results from preservation period, the sourdough breads with addition of Lb. paracasei KB28, Ped. pentosaceus MJK7 were showed the appearance of mold and bacteria growth in 5~6 days, whereas the control were showed in 3 days. As a result, a sensory evaluation indicated the highest overall acceptance in order of Lb. fermentum, Lb. paracasei KB28, Ped. pentosaceus MJK7. Based on these results, Lb. paracasei KB28 can be applicable to improve the quality of sourdough bread.

A novel route to prepare Nd-Fe-B magnetic particles by utilizing both spray drying and reduction/diffu- sion processes was investigated in this study. Precursors were prepared by spray drying method using the aqueous solu- tions containing Nd salt, Fe salt and boric acid with stoichiometric ratios. Precursor particles could be obtained with various sizes from 2 to 10 µm by controlling concentrations of the solutions and the average size of 2 µm of precursors were selected for further steps. After heat treatment of precursors in air, Nd and Fe oxides were formed through desalt- ing procedure, followed by reduction processes in Hydrogen (H2) atmosphere and with Calcium (Ca) granules in Argon (Ar) successively. Moreover, diffusion between Nd and Fe occurred during Ca reduction and Nd2Fe14B particles were formed. With Ca amount added to particles after H2 reduction, intrinsic coercivity was changed from 1 to 10 kOe. In order to remove and leach CaO and residual Ca, de-ionized water and dilute acid were used. Acidic solutions were more effective to eliminate impurities, but Fe and Nd were dissolved out from the particles. Finally, Nd2Fe14B magnetic particles were synthesized after washing in de-ionized water with a mean size of 2 µm and their maximum energy prod- uct showed 9.23 MGOe.

The study on the fabrication of iron powder from forging scales using hydrogen gas has been conducted on the effect of hydrogen partial pressure, temperature, and reactive time. The mechanism for the reduction of iron oxides was proposed with various steps, and it was found that reduction pattern might be different depending on tem- perature. The iron content in the scale and reduction ratio of oxygen were both increased with increasing reactive time at 0.1atm of hydrogen partial pressure. On the other hand, for over 30 minutes at 0.5 atm of hydrogen partial pressure, the values were found to be almost same. In the long run, iron metallic powder was obtained with over 90% of iron content and an average size of its powder was observed to be about 100 µm.

Occupational injury rate of Korea recently slides slightly downward after stagnating around 0.7%'s for more than 10 years. To accelerate this trend, injury prevention for small enterprises is crucially important because vast majority of injuries take place in small enterprises. Considering huge number of small enterprises, we need to focus our efforts to type of riskier industries. By analysing detailed injury data, we select type of industries which need our concentrated prevention efforts. Several preventive measures are recommended, after we made literature survey of case studies for small enterprises. The result identifies riskier type of industries including transportation machinery manufacturing industry type(B), woods & veneer manufacturing industry, etc. Safety of machinery, new enterprises less than 2 years in service and new employees serving less than 6 months are in need for focused prevention efforts. To cope with these vulnerable spots, recommended preventive measures include strengthening of machinery safety standards, early assistance for safety to new enterprises, mandatory safety education before employment, etc.

Sol-gel 코팅제는 금속 소재의 부식 억제를 위해 다양한 분야에서 활용되어지고 있다. 본 연구의 유/무기 하이브리드 코팅제는 methyl trimethoxy silane 과 alumina sol에 3-glycidyloxypropyl trimethoxy silane을 혼합하여 제조하였다. 3-glycidyloxypropyl trimethoxy silane 의 함량에 따라 sol-gel 공정으로 도장된 박막의 내식성, 경도, 그리고 열안정성을 조사하였다. Electrochemical impedance와 potentiodynamic polarization의 측정 결과로부터 도막의 내식성이 3-glycidyloxypropyl trimethoxy silane의 도막 내 장거리 상호작용에서 기인한 접착력 증가와 crack-free 도막의 형성에 의해 개선되었음을 알 수 있었다.

OSHMS(Occupational Safety and Health Management System) is able to define as a typical convergence of all kinds of activities and elements that support maintaining safety at workplace and protecting employee's health. In particular, fundamental function of OSHMS is preventing diverse hazards at workplace through high level of regulation compliance. Furthermore, insuring safety in workplace, protecting employee's health and increasing effectiveness in manufacture are OSHMS's additional functions. Based on the division of manufacture in 2009 Survey on Current Status of Occupational Health & Safety data, the study analyses certain relation between OSHMS and level of regulation compliance. The main finding is that most activities and elements which formed by OSHMS are being affected by regulation clauses.

본 연구는 정부연구개발투자가 민간부문의 고용에 미치는 장기적인 효과를 검증하기 위해 국내 23개 제조업 부문을 대상으로 패널분석을 수행하였다. 1990년대 중반 이후 IT의 급속한 발전과 더불어 국내 제조업 고용구조에 큰 영향을 준 IMF 구제금융에 따른 산업구조 조정기를 중심으로 전체 표본기간을 IMF 이전과 이후로 나누어 정부연구개발투자가 기업의 고용수요에 미친 영향을 실증분석한 결과 다음의 결과를 도출하였다. 첫째, 정부연구개발투자는 단기적으로는 고용을 감소시키는 효과를 나타내지만 시간이 지나면서 신제품 혹은 신산업 창출로 인한 고용의 보상효과가 이를 상쇄하면서 고용창출에 긍정적인 효과를 가진다. 둘째, 민간연구개발투자의 고용창출 효과가 정부연구개발투자의 효과보다 3배 이상 크다. 셋째, 기업의 노동수요에 비용요인인 임금 및 이자율은 높은 유의수준으로 고용에 부정적인 영향을 미치고 있다. 이러한 결과는 향후 정부연구개발투자가 새로운 고용창출을 위한 정책수단으로 활용될 수 있다는 정책적 함의를 제공한다.

Coal tar is the primary feedstock of premium graphitizable carbon precursor. Coal tars are residues formed as byproducts of thermal treatments of coal. Coal tar pitches were prepared through two different heat treatment schedules and their properties were characterized. One was prepared with argon and oxidation treatment with oxygen; the other was prepared with oxygen treatment at low temperature and then argon treatment at high temperature; both used coal tar to prepare coal tar pitches. To modulate the properties, different heat treatment temperatures (300~400˚C) were used for the coal tar pitches. The prepared coal tar pitches were investigated to determine several properties, such as softening point, C/H ratio, coke yield, and aromaticity index. The coal tar pitches were subject to considerable changes in chemical composition that arose due to polymerization after heat treatment. Coal tar pitch showed considerable increases in softening point, C/H ratio, coke yields, and aromaticity index compared to those characteristics for coal tar. The contents of gamma resin, which consists of low molecular weight compounds in the pitches and is insoluble in toluene, showed that the degree of polymerization in the pitches was proportional to C/H ratio. Using an oxidizing atmosphere like air to prepare the pitches from coal tar was an effective way to increase the aromaticity index at relatively low temperature.

소규모 농가에서 많이 하는 느타리버섯 봉지재배는 배지제조시 고압살균(121℃ 90～120)과 상압살균(98℃, 4～10시간)을 사용했으나 최근에는 느타리버섯 생산량은 꾸준히 증가하여 수 요에 비해 공급이 많아 버섯 가격이 하락 하는데다 고유가로 인해 유류비 상승으로 어려움을 격고 있다. 따라서 봉지재배시 회전식 배지제조기를 이용한 발효배지로 재배할 경우 배지혼 합, 수분조절, 살균, 발효 등을 일괄작업 함으로써 상압살균보다 52% 유류를 절감할수 있었 다. 그리고 균배양은 배지 발효시간이 길수록 균사밀도는 치밀해지나 균배양기간은 2～3일, 초발이소요일수 1일 정도 지연되는 경향이었다. 수량성은 64℃발효 36시간 처리한 배지에서 배지크기 600g봉지에서 수한품종은 131.2g/봉지로 8% 증수되었으며, 배지발효시간이 72시간 이 지나면서 배지부피가 20% 이상 줄어 들고, 수량도 감소하는 경향을 보였다. 회전식배지제 조기를 이용한 봉지재배용 발효배지 제조기술의 단계별 과정을 보면 ①기본배지는 면실피(배 지수분 68%)를 사용하며, 봉지당 배지무게는 600g으로 한다. ②회전식배지제조기 내부온도를 스팀열로 60～70℃ 유지하면서 6～8시간 배지를 혼합한다.(회전식배지제조기 회전속도 분당 3～4회) ③배지 혼합후 70℃에서 1시간 유지하고 50℃까지 하온 하면서 가스빼기를 실시한 다. ④건열로 배지온도를 64℃까지 4～6시간 동안 서서히 올린다. ⑤발효온도 64℃에서 36시간 유지후 20℃내외로 하온하여 입봉하여 종균을 접종한다. ⑥입봉․종균접종은 3,000봉 작업시 4～5시간 이상 소요되므로 여름철 고온기에는 잡균오염을 줄이기 위해서는 기온이 낮은 오전10시 이전에 작업 완료하는 것이 유리하다.

목이는 세계적으로 널리 분포되어있고 특히 한국, 일본, 중국, 일본 등지에서 다량의 야생버섯이 발견되고 있다. 목이버섯의 종류는 크게 목이목(Auriculariales) 목이과(Auriculariaceae) 목이속 (Auricularia)에 속하는 목이(Auricularia auricula)와 털목이(Auricularia polytricha)가있고, 흰목이 목(Tremellales) 흰목이과(Tremellaceae) 흰목이속(Tremella)에 속하는 흰목이(Tremella fuciformis)가있다. 이들은 각종 활엽수의 고사목이나 반고사목에서 생장하고 있으며, 버섯의 모양 이 사람의 귀와 같아서 중국에서는 목이(木耳), 우리나라에서는 목이 또는 흐르레기, 일본에서는 해파리 또는 기쿠라케(ｷｸﾗｹ)라하며, 서구에서는 ear mushroom이라한다. 본 연구는 목이에 대한 톱 밥종균 제조를 위해 톱밥 종류에 따른 적정 영양원을 선발하고 선발된 영양원의 배합비율을 설정 하고자 하였고, 선발된 종균의 접종량을 선발하여 목이버섯을 재배하는데 보다 효율적인 재배로 버섯을 생산하는데 안정적인 재배에 기하고자 하였다. 목이의 톱밥종균을 제조하는데 참나무톱밥 과 포플러톱밥을 사용할 경우 참나무톱밥은 영양원으로 미강 20%를 첨가하고, 포플러톱밥은 밀기 울을 10%첨가 하였을 때 균사생육과 밀도가 양호하였고 이때 봉지재배에 적합한 종균 접종량은 참나무톱밥종균은 15g, 포플러톱밥종균은 25g를 접종할 때 오염발생률이 줄고 배양완성률이 높아 적합한 접종량임을 알 수 있었다.

In order to increase the toughness of ZTA(zirconia toughened alumina) ceramics, the present study focused on rearrangement and densification of particles according to the particle size of the parent material. When rough alumina was used for production of ZTA, densification behavior was observed in the specimen sintered at a temperature over 1550˚C. However, it was found that the densification behavior was occurred in the specimen sintered at 1450˚C when fine alumina powder was used. High relative density exceeding 98% was obtained when fine alumina powder was mixed with 15 wt% of 3Y-TZP and sintered at 1600˚C. Also, a hardness of 1820.2 Hv was obtained when a specimen containing 10 wt% of 3Y-TZP was sintered at 1600˚C. In the case of 3Y-TZP containing rough alumina powder that had been sintered the hardness value was around 1720.3 Hv. It was predicted that an improved toughening effect in ZTA could be achieved by using finer alumina powder as the parent material.

Al-based alloys have recently attracted considerable interest as structural materials and light weight materials due to their excellent physical and mechanical properties. For the investigation of the potential of Al-based alloys, a surface porous Al88Cu6Si6 eutectic alloy has been fabricated through a chemical leaching process. The formation and microstructure of the surface porous Al88Cu6Si6 eutectic alloy have been investigated using X-ray diffraction and scanning electron microscopy. The Al88Cu6Si6 eutectic alloy is composed of an α-Al dendrite phase and a single eutectic phase of Al2Cu and α-Al. We intended to remove only the α-Al phase and then the Al2Cu phase would form a porous structure on the surface with open pores. Both acidic and alkaline aqueous chemical solutions were used with various concentrations to modify the influence on the microstructure and the overall chemical reaction was carried out for 24 hr. A homogeneous open porous structure on the surface was revealed via selective chemical leaching with a H2SO4 solution. Only the α-Al phase was successfully leached while the morphology of the Al2Cu phase was maintained. The pore size was in a range of 1~5μm and the dealloying depth was nearly 3μm. However, under an alkaline NaOH, aqueous solution, an inhomogeneous porous structure on the surface was formed with a 5 wt% NaOH solution and the morphology of the Al2Cu phase was not preserved. In addition, the sample that was leached by using a 7 wt% NaOH solution crumbled. Al extracted from the Al2Cu phase as α-Al phase was dealloyed, and increasing concentration of NaOH strongly influenced the morphology of the Al2Cu phase and sample statement.

The purpose of this study was to determine the optimal mixing conditions for two different amounts of turmeric (Curcuma longa L.) powder and olive oil for the processing of chicken sausage. The experiment was designed according to the central composite design of response surface methodology, with ten experimental points, including two replicates for turmeric powder and olive oil. The physicochemical and mechanical analysis of each sample, including water holding capacity, moisture content, lightness, redness, yellowness, hardness, chewiness, gumminess, and cohesiveness, showed significant differences. The results from sensory evaluations also showed very significant differences in color, flavor, tenderness, chewiness, and overall quality. The optimal formulation, calculated by numerical and graphical methods, was 1.89 g of turmeric powder and 9.77 g of olive oil. Under these conditions, the model predicted pH-6.01, salinity-0.20, WHC-94.88, L* value-61.13, b* value-37.45, hardness-36.66×102 (N), springiness-8.70 (mm), chewiness-26.88×103 (N×mm).

Polyacrylonitrile (PAN) 기질고분자를 용매인 dimethylformamide (DMF)에 녹인 후 전기방사법을 이용하여 polyacrylonitrile nanofibers membrane (PAM)을 제조하였으며, 정밀여과(microfiltration) 적용을 위해, 제조된 PAM 샘플들의 layer 수를 변화시켜, 기공크기를 조절하였다. 또한, 순수투과도(water-flux) 향상을 위해 poly (ethylene glycol) methyl ether methacrylate와 azobisisobutylronitrile (AIBN)을 이용하여 자유 라디칼 중합(free radical polymerization)을 통해 합성된 AN‐ PEGMA 공중합체를 PAN과 3:1의 비율로 혼합한 후 위와 같은 방법으로 다공성 막(PAM/APM)을 제조하였으며, FT-IR과 E.D.S 분석을 통해 PAM 샘플과 비교⋅분석하였다. Scanning Electron Microscope (SEM) 분석과 기공크기, 기공도 실험을 통해 균일한 직경(400∼600 nm)과 균일한 기공특성(0.5∼0.4 μm)을 가진 다공성 막이 제조되었음을 확인할 수 있었다. 순수 투과도 측정을 통해 정밀여과용 막으로의 활용가능성을 조사하였으며, AN‐PEGMA 공중합체가 도입된 PAM/APM의 경우 상 용막인 polyvinylidenefluoride (PVdF)에 비해 순수투과도가 상대적으로 높은 값을 나타내었다. 위의 결과로부터 전기방사법으로 제조된 PAN 나노섬유막들은 정밀여과용 막으로서 충분한 활용가능성이 있다고 판단된다.

중심합성계획에 따라 마늘의 첨가량(1.5~10.45%)과 추출시간(52.8~300 min)을 독립변수로 하고, 고형분 함량, ABTs 라디칼 소거활성, ALDH 및 15% 에탄올에 대한 ADH 활성을 종속변수로 하여 다슬기와 마늘 혼합물의 최적 추출조건 설정을 위한 반응표면분석을 실시하였다. 고형분의 함량에 대해 예측된 정상점에서 최대값은 0.49 Brix%였고, 이때의 추출조건은 마늘 첨가량 6.17%, 추출시간 191분이었다. ABTs 라디칼 소거활성은 마늘 첨가량 7.95%, 추출시간 194분에서 최대값 96.68%를 나타내는 것으로 예측되었다. ALDH의 활성은 마늘 첨가량 5.64%, 추출시간 172분에서 142.18%의 최대값을 가지며, ADH 활성이 최대화되는 정상점에서 최대값은 214.89%였고, 이때 최적 추출조건은 마늘첨가량 8.53%, 추출시간 184분이었다. 네 가지 종속변수의 최대값을 얻기 위한 최적 추출조건의 범위는 마늘첨가농도 5.64~8.53%, 추출시간 172~194분이었다.