In this study, development of the manufacturing system for the oriental medicine needle was carried through the wire drawing from the wire supply, straightness, heat treatment and surface treatment processes, and finally wire cutting or winding by the online process. As a result, a prototype manufacturing system for the oriental medicine needle wire has been developed. It has been shown that all development targets, such as, straightness, precision, surface roughness, tensile strength, discoloration, noise, diameter range and maximum production speed have been satisfied through the performance test.
TiCoxFe1-x(x=0.50~1.00)계 합금을 제조하고, 합금의 특성을 X-ray diffractometer (XRD), pressure composition temperature (PCT)곡선, scanning electron microscopy (SEM)에 의해 조사하였고, TiCoxFe1-x(x=0.50~1.00)-stainless steel (SS) 복합막에 대해 H2-N2 혼합기체분리실험을 하였다. X-선 회절분석에 의하면 TiCoxFe1-x(x=0.50~1.00)계 합금의 결정구조는 TiCo와 같은 입방정구조이었다. TiCoxFe1-x(x=0.50~1.00)계 합금은 120°C에서 hysteresis현상을 나타내었고, 합금 중 Fe의 양이 증가함에 따라 x=0.90~1.00과 0.50~0.55 범위에서는 hysteresis가 증가하였고, x=0.55~0.90 범위에서는 감소하였다. 가장 작은 hysteresis를 나타낸 합금은 TiCo0.55Fe0.45이었다. 120°C에서 TiCoxFe1-x(x=0.50~1.00)-SS 복합막의 수소투과압력의 최저값은 TiCo0.55Fe0.45에서 2.5 atm을 나타내었고, 최대값은 TiCo0.90Fe0.10에서 10 atm을 나타내었다. TiCoxFe1-x(x=0.50~.00)-SS 복합막에 의하여 120°C에서 H2-N2 혼합기체를 분리하는 경우, 가장 우수한 복합막은 고압부의 수소투과압력이 2.5 atm으로 가장 낮고, hysteresis가 가장 작은 TiCo0.55Fe0.45-SS 복합막이었다.
수용성 고분자인 poly(vinyl alcohol) (PVA)에 가교제인 sulfosuccinic acid (SSA)를 첨가하여 가교반응을 통해 물에 용해되지 않는 막을 제조하였으며, 이온교환능력을 부여하기 위해 poly(4-styrene sulfonic acid-co-maleic acid) (PSSA_MA)를 PVA 질량대비 70, 80, 90 wt%로 달리 첨가하여 막을 제조하였다. 제조한 막의 특성을 알아보기 위해 FT-IR, 함수율, 이온교환용량, 이온전도도, 메탄올 투과도를 측정하였다. 함수율과 이온교환용량, 이온전도도는 PSSA_MA 함량이 증가할수록 증가하는 경향을 나타내었으며 메탄올 투과도는 감소하는 경향을 나타내었다. 특성평가 결과 본 실험 막의 최적 조성은 PVA10/SSA9/ PSSA_MA80으로 도출되었다
Porous W with controlled pore structure was fabricated by thermal decomposition and hydrogen reduction process of PMMA beads and WO3 powder compacts. The PMMA sizes of 8 and 50 μm were used as pore forming agent for fabricating the porous W. The WO3 powder compacts with 20 and 70 vol% PMMA were prepared by uniaxial pressing and sintered for 2 h at 1200oC in hydrogen atmosphere. TGA analysis revealed that the PMMA was decomposed at about 400oC and WO3 was reduced to metallic W at 800oC. Large pores in the sintered specimens were formed by thermal decomposition of spherical PMMA, and their size was increased with increase in PMMA size and the amount of PMMA addition. Also the pore shape was changed from spherical to irregular form with increasing PMMA contents due to the agglomeration of PMMA in the powder mixing process.
WS2-W-WC embedded carbon nanofiber composites were fabricated by using electrospinning method for use in high-performance supercapacitors. In order to obtain optimum electrochemical properties for supercapacitors, WS2 nanoparticles were used as precursors and the amounts of WS2 precursors were controlled to 4 wt% (sample A) and 8 wt% (sample B). The morphological, structural, and chemical properties of all samples were investigated by means of field emission photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. These results demonstrated that the embedded phases of samples A and B were changed from WS2 to WS2-W-WC through carbothermal reaction during carbonization process. In particular, sample B presented high specific capacitance (~119.7 F/g at 5 mV/s), good high-rate capacitance (~60.5%), and superb cycleability. The enhanced electrochemical properties of sample B were explained by the synergistic effect of the using 1-D structure supports, increase of specific surface area, and improved conductivity from formation of W and WC phases.
This study investigates the microstructure and thermal shock properties of polycrystalline diamond compact (PDC) produced by the high-temperature, high-pressure (HPHT) process. The diamond used for the investigation features a 12~22 μm- and 8~16 μm-sized main particles, and 1~2 μm-sized filler particles. The filler particle ratio is adjusted up to 5~31% to produce a mixed particle, and then the tap density is measured. The measurement finds that as the filler particle ratio increases, the tap density value continuously increases, but at 23% or greater, it reduces by a small margin. The mixed particle described above undergoes an HPHT sintering process. Observation of PDC microstructures reveals that the filler particle ratio with high tap density value increases direct bonding among diamond particles, Co distribution becomes even, and the Co and W fraction also decreases. The produced PDC undergoes thermal shock tests with two temperature conditions of 820 and 830, and the results reveals that PDC with smaller filler particle ratio and low tap density value easily produces cracks, while PDC with high tap density value that contributes in increased direct bonding along with the higher diamond content results in improved thermal shock properties.
The porous metals are known as relatively excellent characteristic such as large surface area, light, lower heat capacity, high toughness and permeability. The Fe-Cr-Al alloys have high corrosion resistance, heat resistance and chemical stability for high temperature applications. And then many researches are developed the Fe-Cr-Al porous metals for exhaust gas filter, hydrogen reformer catalyst support and chemical filter. In this study, the Fe-Cr-Al porous metals are developed with Fe-22Cr-6Al(wt) powder using powder compaction method. The mean size of Fe-22Cr-6Al(wt) powders is about 42.69 μm. In order to control pore size and porosity, Fe-Cr-Al powders are sintered at 1200~1450oC and different sintering maintenance as 1~4 hours. The powders are pressed on disk shapes of 3 mm thickness using uniaxial press machine and sintered in high vacuum condition. The pore properties are evaluated using capillary flow porometer. As sintering temperature increased, relative density is increased from 73% to 96% and porosity, pore size are decreased from 27 to 3.3%, from 3.1 to 1.8 μm respectively. When the sintering time is increased, the relative density is also increased from 76.5% to 84.7% and porosity, pore size are decreased from 23.5% to 15.3%, from 2.7 to 2.08 μm respectively.
Synthesis of nano-silica using water glass in a Sol-Gel process is one of several methods to manufacture nano-silica. In nano-silica synthesized from water glass, there are various metal impurities. However, synthesis of nano-silica using water glass in a Sol-Gel process is an interesting method because it is relatively simple and cheap. In this study, nano-silica was synthesized from water glass; we investigated the effect of pH on the synthesis of nano-silica. The morphology of the nanosilica with pH 2 was flat, but the surface of the nano-silica with pH 10 had holes similar to small craters. As a result of ICPOES analysis, the amount of Na in the nano-silica with pH 2 was found to be 170 mg/kg. On the other hand, the amount of Na in the nano-silica with pH 10 was found to be 56,930 mg/kg. After calcination, the crystal structure of the nano-silica with pH 2 was amorphous. The crystal structure of the nano-silica with pH 10 transformed from amorphous to tridymite. This is because elemental Na in the nano-silica had the effect of decreasing the phase transformation temperature
Sb-doped SnO2(ATO) thin films were prepared using electrospinning. To investigate the optimum properties of the electrospun ATO thin films, the deposition numbers of the ATO nanofibers(NFs) were controlled to levels of 1, 2, 4, and 6. Together with the different levels of deposition number, the structural, chemical, morphological, electrical, and optical properties of the nanofibers were investigated. As the deposition number of the ATO NFs increased, the thickness of the ATO thin films increased and the film surfaces were gradually densified, which affected the electrical properties of the ATO thin films. 6 levels of the ATO thin film exhibited superior electrical properties due to the improved carrier concentration and Hall mobility resulting from the increased thickness and surface densification. Also, the thickness of the samples had an effect on the optical properties of the ATO thin films. The ATO thin films with 6 deposited levels displayed the lowest transmittance and highest haze. Therefore, the figure of merit(FOM) considering the electrical and optical properties showed the best value for ATO thin films with 4 deposited levels.
Ceramics biomaterials are useful as implant materials in orthopedic surgery. In this study, porous
HA(hydroxyapatite)/β-TCP(tricalcium phosphate) composite biomaterials were successfully fabricated using HA/β-TCP powders with 10-30 wt% NH4HCO3 as a space holder(SH) and TiH2 as a foaming agent, and MgO powder as a binder. The HA/β-TCP powders were consolidated by spark plasma sintering(SPS) process at 1000 oC under 20 MPa conditions. The effect of SH content on the pore size and distribution of the HA/β-TCP composite was observed by scanning electron microscopy(SEM) and a microfocus X-ray computer tomography system(SMX-225CT). These microstructure observations revealed that the volume fraction of the pores increased with increasing SH content. The pore size of the HA/β-TCP composites is about 400-500 μm. The relative density of the porous HA/β-TCP composite increased with decreasing SH content. The porous HA/β-TCP composite fabricated with 30%SH exhibited an elastic modulus similar to that of cortical bone; however, the compression strength of this composite is higher than that of cortical bone.
Numbers of successful companies in the world develop The core values of action in order to produce effective human resource management and organization culture. Core values are belief, and values that are shared by all members to maintain organization. Also, The core values function as to inspire motivation and decision making for organization's identity and assist to settle their own unique culture. Therefore, this study is to figure out the effect of core values to the members of organization and management performance from small and medium company that is comparatively less focused to settle their own core values.
Last five years, Occupational injury rate is declining but still a standstill as 2%, if the rate of deaths all people from 2% to 1% in 2013, but decreased as, occupational safety and health in terms industrial accidents yet has a very weak structure in very small Manufacturing workplace. The purpose of this study was to survey a 1:1 directly person interviews with a structured questionnaire intended for 150 a very small manufacturing workplace. In the results, working with non-regular(informal) workers is one in 10 persons 11.7% and female workers is about three people on 10 persons with 31.0%, and that 75% of non-regular workers who are mainly engaged in the production line appeared. And the work-related injury and accident experience was 4.0% and the occupational injury rate was 1.24%, especially occupational injury rate of older workers was 3.65%, a female workers 1.72%. Workplace risk assessment carried out in response that it was very low as 9.3% of the total. In the technology and funding programs that are supported by the government, was highest with 62.7% of the clean support program awareness, awareness of the rest of the programs is about 10-14% lower. And the satisfaction of supporting a clean support program were the highest 81.3%.
The purpose of this study is to evaluate quality characteristics of the Cheonggukjang produced using rice straw-derived Bacillus cereus free starter culture (RiBS1). The Cheonggukjang was prepared in 0.1 and 1.0% inoculum concentrations of starter culture and fermented from 12 hr to 72 hr at 40 and 50℃. Amino-nitrogen contents after 48 hr fermentation were 559.6~590.2 mg% and 393.8~494.0 mg% at 40 and 50℃, respectively. Sensory evaluation showed that the Cheonggukjang fermented using RiBS1 starter for 48 hr at 50℃ was better than the control. And we inspected on B. cereus and biogenic amine in the Cheonggukjang produced using RiBS1 starter. As a results, B. cereus was not detected and histamine and tyramine of biogenic amine were 5.53 ± 0.13 ~ 39.96 ± 0.62 mg/ kg. This research results showed that rice straw-derived B. cereus free starter culture (RiBS1) will be produce the Cheonggukjang with good flavour and taste.
본 연구에서는 이산화탄소 고정화에 있어 이산화탄소 전환을 위해 MEA를 이용한 습식화학흡 수법의 셔틀메카니즘을 도입하였다. 또한 알칼리 무기물질을 다량 함유한 산업부산물을 습식탄산화법을 이용해 처리하고자 하였다. 즉, 산업부산물의 화학적 처리를 통해 칼슘이온을 용출하였다. 산성물질을 이용한 용출상징수를 ICP로 분석한 결과, 칼슘이온이 최대 17,900 ppm(1.79%)을 확보하였다. 또한 MEA를 이용한 습식 흡수공정을 통해 상온, 상압조건의 이산화탄소 분위기에서 94%의 전환률을 얻었 다. 슬러지의 액상탄산화를 통해 슬러지 mg 당 0.175 mg의 이산화탄소를 고정하였으며, 최종생성물의 XRD 분석결과 일반적인 탄산칼슘의 결정구조인 calcite 형상을 확인하였다.
본 연구는 유채 꽃가루 분말의영양성분 분석과 파쇄한 꽃가루 분말을 이용하여 효모 배양용 액체배지와 고체배지를 제조하여 효모 배양효율을 분석하였다. 유채 꽃가루 분말(100 g)은 탄수화물 58.9 g, 단백질 20.8 g, 지방 4.1 g, 회분 2.5 g 및 수분 13.7 g으로 구성되었다. 당질 중에서는 Fructose(13.7 g), Glucose(11.1 g)와 Sucrose(6.6 g), 미네랄 중에서는 K(606.7 mg)와 P(603.3 mg) 함 향이 높았다. 유리 아미노산은 Glutamic acid(2,482.4 mg), Aspartic acid(2,136.5 mg), Lysine(1,648.3 mg), 및 Leucine(1,631.1 mg) 순으로 많았다.
유채 꽃가루분말을 단독 또는 NaCl을 첨가하여 액체배지 및 고체배지 제조하고 효모를 배양한 결 과, 꽃가루 분말이 15 g/L 이상 함유된 액체배지는 효모 배양 후 건물중이 YPD 배지(대조구)에 비해 많았고, 꽃가루 분말의 농도 의존적으로 효모 건물중이 증가하였다. 또한 액체배지에 NaCl을 1~20 g/L 추가 시 배양된 효모의 건물중이 한층 더 증가하였다. 유채 꽃가루로 제조한 고체배지를 이용하여 효모 를 배양(48시간)한 결과, 콜로니(colonies) YPD 배지와 유사하게 잘 자랐다.
생분해성 고분자인 셀룰로오스 아세테이트(CA)를 매트릭스로 용액 중합된 HCl이 50% 정도 도핑된 PAni를 첨가하여 도전성 PCA 복합 필름을 제조하여 기계적, 전기적 특성 및 표면 morphology를 고찰하였다. PCA 복합 필름의 인장강도는 PAni 함유량 5 wt% 인 경우 순수 CA 필름(377.1 kgf/cm2)에 비해 27% 정도 감소된 275.2 kgf/cm2를 나타내었으며, 신율도 7.65%에서 4.35% 정도로 감소하였다. 표 면저항은 PAni의 함량에 따라 감소하였으며, PAni 함유량이 5 wt%인 PCA05의 경우 7.0x109 Ω/sq로 정전기 방지용 필름으로 사용이 가능할 정도였다. 표면 정전기량의 소멸 속도도 PAni 함량에 따라 비례 하여 빨라짐을 확인하였다. PCA 복합 필름의 열적 안정성은 PAni 함량이 늘어남에 따라 분해온도가 낮 아졌으며, 최종 재(char)의 함량은 PAni의 함량에 비례하였다. 최종 재의 함량을 이용하여 미지의 PCA 복합 필름 중의 PAni의 분율을 계산할 수 있을 것으로 판단된다.
본 연구에서는 꽃송이버섯 건물과 powder를 각각 Yeast Extract broth와 MRS broth에서 Lactoballius 4종(L. plantarum, L. acidophilus, L. helveticus, and L. delbrueckii)과 함께 발효시켰다. 발효액의 final pH는 pH 3.9±0.02로 유산균의 일반적인 final pH 값과 일치함을 통해 유산균의 발효를 확인하였고, 유산균에 의한 꽃송이버섯 발효의 효과를 β-glucan 함량을 통하여 확인하였다. Yeast Extract broth 발효액은 YSB-2LP 1.65 g/100 g으로 β-glucan을 거의 함유하고 있지 않았지만 MRS broth 발효액은 Yeast Extract broth 발효액의 10배에 달하는 MPB-1LP 10.84 g/100 g을 함유하고 있었다. MPB-1LP는 꽃송이버섯 powder와 L.actobacillus plantarum으로 발효한 발효액으로 pH stress로 인해 만들어진 L. plantarum의 β-D-glucosidase에 의해 분해된 고분자량의 수용성 β-glucan이라 사료된다. 꽃송이버섯을 powder 상태로 L. plantarum과 함께 발효시켰을 때 꽃송이버섯의 수용성 β-glucan 추출 효율을 높일 수 있으며, 본 연구의 결과는 꽃송이버섯 유산균 발효물의 면역촉진 작용 연구를 위한 기초연구자료로 활용될 수 있을 것이다.
Activated carbon fibers(ACFs) were prepared in this research from a polyacrylonitrile(PAN) precursor with the KOH(1~4 M) pretreatment and following activation at 800oC in a lab-scale. The sample ACFs were characterized according to their textural properties, and evaluated for CO2 adsorption capacity. The surface area and pore volume of ACFs increased according to the pretreatment with KOH; for example, 4M-KOH aqueous solution resulted in 1552.5 m2/g specific surface area and 0.605 cc/g pore volume. It also showed high CO2 adsorption amount(3.11 mmol/g) which showed a proportional increase with reaction pressure.
Porous metals are called as a new material of 21th century because they show not only extremely low density, but also novel physical, thermal, mechanical, electrical, and acoustic properties. Since the late in the 1990‘s, considerable progress has been made in the production technologies of many kinds of porous metals such as aluminum, titanium, nickel, copper, stainless steel, etc. The commercial applications of porous metals have been increased in the field of light weight structures, sound absorption, mechanical damping, bio-materials, thermal management for heat exchanger and heat sink. Especially, the porous metals are promising in automotive applications for light-weighting body sheets and various structural components due to the good relation between weight and stiffness. This paper reviews the recent progress of production techniques using molten metal bubbling, metal foaming, gas expansion, hollow sphere structure, unidirectional solidification, etc, which have been commercialized or under developing, and finally introduces several case studies on the potential applications of porous metals in the area of heat sink, automotive pannel, cathod for Ni-MH battery, golf putter and medical implant.
현재 각 시·도 지차체의 국도 70%이상이 불투수성 면적이며, 불투수성 면적의 증가는 우천 시 수막현 상으로 인한 교통사고, 도시형 우심 피해 증가, 하천수의 감소, 지하수의 고갈 등의 물 순환 문제와 열섬 현상을 발생시키는 주요 원인으로 지목받고 있다. 이러한 시점에서 투수성 포장은 도로 및 보도에 사용이 많이 이루어 졌으나 기존의 밀입도 포장에 비해 인위적으로 형성시킨 공극으로 인하여 강우 및 강설 등에 의한 수분이 투수성 포장을 자유롭게 이동할 수 있어 수분손상에 의한 포장체의 변형 및 처짐으로 골재의 박리·박락 현상과 균열 및 포트홀 등으로 포장이 파손되는 경우가 빈번히 발생하고 있다. 한편, 실온에 서 사용이 가능한 메틸메타아크릴수지(MMA: Methyl Methacrylate Reactive Resin)는 낮은 온도(영하 30℃)에서도 작업이 가능하며 염화칼슘 등의 유입에도 손상 없이 견디는 내화학성 및 내염성을 가지고 뛰 어난 접착성을 가지고 있다. MMA 수지의 경우 에폭시 수지 및 우레탄 수지와 같은 액체기와 액체 경화제 로 구성되어 있는 여타 반응성 수지와 달리 상온에서 사용가능한 결합재에 적용할 경우 MMA 수지와 분 말경화제의 배합 및 사용량에 대한 특성을 명확히 적용할 필요가 있다. 본 연구에서는 폐아스콘 순환골재를 전량 활용한 투수성 재생아스팔트 제조를 위한 MMA 수지 상온 재 생아스팔트용 결합재 개발에 앞서 MMA 수지 및 경화제의 종류에 따른 배합의 중합열과 경화속도를 분석 하여 기초자료로 활용하고자 한다. 실험 결과, 단일형 MMA 수지의 경우 경화제의 B.P.O 농도가 높고, 첨가량이 증가할수록 중합열은 증가 하였으며, 경화시간은 단축되는 경향을 보였다. B.P.O 농도 50%의 경우 2%~4%첨가량의 경화시간은 26~40분, 중합열은 82.4℃~94.6℃로 안정적인 중합 반응을 보였으며 5%의 시편에서는 100.4℃의 높은 중 합열이 발생하여 이에 따른 자동가속화반응으로 인한 점도 증가로 기포가 발생하여 공극이 생기는 현상이 발견되었다. B.P.O 농도 40%의 경우 2%~5%첨가량의 경화시간은 23~52분, 중합열은 77.6℃~98.5℃ 안 정적인 중합 반응을 보였다. 하지만 B.P.O 농도 50% 및 40% 모두 첨가량 1%이하에서는 반감기가 길어짐에 따라 단위 시간당 생성되는 자유라디칼의 수가 작아지면서 입자 핵생성 기간이 길어져 반응 초기에 생성된 입자 핵들이 화합하여 성장할 확률과 중합속도 또한 낮아지게 되어 경화시간이 60분 이상 증가하였으며 중 합열 또한 61.5~65.3℃로 낮게 나타났다. 상도형 MMA 수지의 경우 경화시간은 22~30분, 중합열은 59. 1℃~64.2℃로 농도와 첨가량에 의한 차이는 크지 않았으며, 단일형 MMA 수지에 비해 빠른 경화시간과 낮 은 중합열로 안정적인 중합반응을 보였다. 하지만 경화제 4%이상 첨가할 경우에는 농도에 관계없이 중합열 이 감소하여 10℃이상의 차이를 보였으며, 이는 경화제의 첨가량이 증가하면서 분자간의 응집력으로 인하여 균일한 분산이 이루어지지 않아 MMA 수지와 중합반응이 제대로 이루어지지 않은 것으로 판단된다.