Internally confined hollow reinforced concrete (ICH RC) wind power towers were designed for various turbines sizes. Their cross sections were designed to have equal diameters to those of general steel wind power towers corresponding 3.6MW and 5.0MW turbines. And also, the sections with the average diameter of 3.6MW and 5.0MW turbines were designed. For the determined diameters, several cross sections were designed for various hollow ratios. The designed sections were set to have almost equal longitudinal reinforcement ratios. The performance analyses for the designed cross sections were carried out and the analysis results showed that the ICH RC wind power tower had enough strength for the required design loads.

The Purpose of this study is to empirically examine the impact of various internal and external innovation activities of SMEs on their innovation performances in the field of electronics and communication industry. Drawing upon the literature review, internal and external innovation activities are defined and conceptualized, and independent, dependent and moderator variables are developed. We have used survey-based data for this study from the survey of technology innovation activities in manufacturing industry, which was conducted by the Science and Technology Policy Institute (STEPI) in 2010. The main result of this study shows that there were no significant differences in the impact of innovation activities on market performance according to the size of SMEs. On the other hands, we found that there were significant differences in the impact of innovation activities on technological innovation performance according to the size of SMEs. Therefore, in order to make high technological innovation performance, companies in the field of electronics and communication industry need to properly implement the internal and external innovation activities by considering their size.

원자력이용시설에서 발생한 작은 크기의 금속 조각들을 효과적으로 제염하는 스마트 장치를 개발하였다. 이 장치는 자성연 마재를 포함한 영역의 자속밀도를 연속적으로 변화시키는 방법과 초음파를 이용하는 다중 제염장치이다. 한편, 제염 효율을 높이기 위해 제염 장치가 제염 대상 전체에 작용하도록 장치들의 구성을 수정하였다. 개발된 장치들의 최적 작동조건을 도 출하여 샘플로 선정한 소형의 금속방사성페기물에 대하여 자기장과 초음파제염을 각각 15분간 실시하였다. 그 결과 제염계 수의 범위는18~56으로 크게 향상되었으며 제염 후 모든 샘플은 백그라운드(BKG)값 이하로 확인되었다.

Titanium and its alloys are useful for implant materials. In this study, porous Ti-Nb-Zr biomaterials were successfully synthesized by powder metallurgy using a NH4HCO3 as space holder and TiH2 as foaming agent. Consolidation of powder was accomplished by spark plasma sintering process(SPS) at 850˚C under 30 MPa condition. The effect of high energy milling time on pore size and distribution in Ti-Nb-Zr alloys with space holder(NH4HCO3) was investigated by optical microscope(OM), scanning electron microscope(SEM) & energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD). Microstructure observation revealed that, a lot of pores were uniformly distributed in the Ti-Nb-Zr alloys as size of about 30-100μm using mixed powder and milled powders. In addition, the pore ratio was found to be about 5-20% by image analysis, using an image analyzer(Image Pro Plus). Furthermore, the physical properties of specimens were improved with increasing milling time as results of hardness, relative density, compressive strength and Young's modulus. Particularly Young's modulus of the sintered alloy using 4h milled powder reached 52 GPa which is similar to bone elastic modulus.

Fe-Cr-Al powder porous metal was manufactured by using new electro-spray process. First, ultra-finefecralloy powders were produced by using the submerged electric wire explosion process. Evenly distributed colloid(0.05~0.5% powders) was dispersed on Polyurethane foam through the electro-spray process. And then degreasing andsintering processes were conduced. In order to examine the effect of cell size (200 µm, 450 µm, 500 µm) in process,pre-samples were sintered for two hours at temperature of 1450˚C, in H₂ atmospheres. A 24-hour thermo gravimetricanalysis test was conducted at 1000˚C in a 79% N₂ + 21% O₂ to investigate the high temperature oxidation behavior ofpowder porous metal. The results of the high temperature oxidation tests showed that oxidation resistance increased withincreasing cell size. In the 200 µm porous metal with a thinner strut and larger specific surface area, the depletion ofthe stabilizing elements such as Al and Cr occurred more quickly during the high-temperature oxidation compared withthe 450, 500 µm porous metals.

We demonstrated size control of Au nanoparticles by heat treatment and their use as a catalyst for single-walled carbon nanotube (SWNTs) growth with narrow size distribution. We used uniformly sized Au nanoparticles from commercial Au colloid, and intentionally decreased their size through heat treatment at 800 oC under atmospheric Ar ambient. ST-cut quartz wafers were used as growth substrates to achieve parallel alignment of the SWNTs and to investigate the size relationship between Au nanoparticles and SWNTs. After the SWNTs were grown via chemical vapor deposition using methane gas, it was found that a high degree of horizontal alignment can be obtained when the particle density is low enough to produce individual SWNTs. The diameter of the Au nanoparticles gradually decreased from 3.8 to 2.9 nm, and the mean diameter of the SWNTs also changed from 1.6 to 1.2 nm for without and 60 min heat treatment, respectively. Raman results reconfirmed that the prolonged heat treatment of nanoparticles yields thinner tubes with narrower size distribution. This work demonstrated that heat treatment can be a straightforward and reliable method to control the size of catalytic nanoparticles and SWNT diameter.

본 연구는 2010 국민건강영양조사 원시자료에서 식품섭취 조사를 실시한 대상자 8,019명 중 19~64세 연령의 성인 대상 자 4,556명(56.8%)의 원자료를 이용하여 19~64세 성인의 상 용음식(밥류, 면․만두류, 국․탕류, 찌개류) 1인 1회 섭취분 량에 대한 정보를 제공하고, 2005년 국민건강영양조사자료 를 이용하여 설정된 기존자료와의 비교를 통하여 한국 성인 의 주요 상용음식의 1인 1회 섭취분량의 변화 패턴을 알아보 고자 하였다. 밥류 중 가장 높은 섭취빈도를 보인 것은 쌀밥 이었고, 1인 1회 섭취분량은 265 ㎖로 2005년 자료로부터 설 정된 250 ㎖와 유사하였다. 두 번째로 높은 섭취 빈도를 보인 것은 잡곡밥으로 3,472의 빈도로 거의 흰쌀밥에 가까운 섭취 빈도였고, 1회 1회 섭취분량은 250 ㎖였다. 면․만두류 중 가 장 섭취빈도가 높은 음식은 라면이었고, 1인 1회 섭취분량은 500 ㎖로 기존에 설정된 400 ㎖에 비하여 25.0%의 증가를 보 였다. 칼국수와 짬뽕은 2005년 설정량에 비하여 40% 이상의 감소를 보였다. 국․탕류에서는 콩나물국의 섭취빈도가 가장 높았고, 가장 높은 섭취빈도를 보인 국은 콩나물국의 1인 1회 섭취분량은 250 ㎖로 기존 설정량과 동일하였다. 상용 음식 으로 설정된 39종의 국 종류에서 기존 설정량과 항목이 일치 하는 28종 중 11종이 1인 1회 섭취분량의 감소가 보였다. 섭 취 빈도가 가장 높은 찌개류는 된장찌개였고, 1인 1회 섭취분 량은 125 ㎖로 기존 설정량(175 ㎖)에 비하여 28.6%의 감소를 보였다. 다음으로 섭취빈도가 높은 찌개류인 김치찌개의 1인 1회 섭취분량은 200 ㎖로 기존의 섭취분량(250 ㎖)에 비하여 20.0%의 감소를 보였다. 이상의 결과에서 2010년 국민건강영 양조사 자료로부터 설정된 1인 1회 섭취분량은 밥류의 경우 큰 변화가 없었으며, 섭취빈도가 높은 주요 국과 찌개의 경우 는 감소, 면류의 경우 라면은 증가, 칼국수와 짬뽕의 경우는 감소를 나타내었다. 이러한 변화는 한국 성인 상용식품의 1 인 1회 섭취분량이 조금씩 변화되고 있음을 보여주고, 국과 찌개류 섭취량의 감소 추세는 나트륨의 저감화 정책 차원에 서 바람직한 변화로 사료된다.

The object of this paper is to examine the noise generating mechanism at manufacturing process of metal material products. To accomplish the object; A noise generating mechanism of high noise machine, which is mounted in the small and medium size enterprise, was investigated. The measurement method of the noise for the machine by manufacturers were investigated. The noise at the 250 points of the manufacturing process machine in the 40 processes of the 3 factories, 3 business fields was measured. The database of the noise was built from the measurement data. The major sound sources and frequency range for the manufacturing process of metal material product machine was investigated.

본 연구에서는 2011년 우리나라 10개의 중대형 인공호에서 배스의 우점도에 의한 외래종 영향 및 이에 대 한 어류 군집 구조 분석을 실시하였고, 이들이 출현하는 호수에 대한 이화학적 수질특성을 분석하였다. 10개 인공호에서 출현한 어류는 13과 52종이었으며, 배스의 상대 풍부도는 전체 어종들 중 13%를 차지하여, 출현한 어류들 중 3번째로 높게 우점하는 것으로 나타났다. 이런 결과는 향후 배스가 수체내에서 최상위 포식자로서의 포식압 및 생태적 지위 특성 때문에 많은 인공호들에서는 본 배스의 외래종 번성에 의한 생태계 교란 효과가 극대화 될 수 있음을 제시하였다. 전체 조사 대상 인공호들 중 평택호에서 배스의 상대 풍부도는 60%로서 가장 높게 나타난 반면, 대청호에서 풍부도는 3%로서 가장 낮게 나타났다. 배스 서식지에 대한 이∙화학적 수질분석 결과에 따르면, COD는 평균 4.5±2.5 mg L-1 였고, 총인 (TP) 농도는 0.058±0.047 mg L-1, 총질소 (TN)는 2.2±1.4 mg L-1로 나타났다. 인(P)과 질소(N) 의 농도 분석에 따르면, 평택호, 낙동강하구언, 주남저수지 등의 수체는 부영양화 현상이 높은 것으로 나타났다. 배스의 상대풍부도와 수질자료의 비교분석에 따르면, 두 변수는 통계학적으로 유의한 상관관계 (p.0.05)를 보이지 않았다. 즉, 배스의 분포 및 풍부도 특성은 이 화학적 수질도 중요하겠지만, 이들보다는 여러 타 요인들, 즉, 물리적 서식지 특성, 이용 가능한 먹이양 및 경쟁생물의 밀도 등에 의해 더 영향 받을 것으로 추정되었다.

본 연구에서는 입경·비중 겸용 밭작물 곡물 선별기 개발을 위한 전 단계로서, 밭작물 곡물의 완전립과 불량립의 기하학적, 공기역학적, 마찰 특성을 측정하고, 선별기 설계에 적용하기 위한 선별 요인을 분석하였다. 측정된 곡물의 기하학적 특성 결과(길이, 폭, 두께)를 이용하여 스크린의 치수와 형상을 결정하여 선별기를 제작하여 선별시험을 한 결과 선별효율은 콩의 경우 94.7%, 커피는 92.0%, 아몬드는 74.5%, 옥수수는 90.0%로 나타났다. 측정된 곡물의 마찰 특성 결과를 이용한 고무벨트 선별 시험 결과 콩의 경우 벨트 속도 0.5 m/s, 벨트 각도 5˚ 일 때 선별효율이 88.2%로 가장 높게 나타났다. 측정된 곡물의 공기역학적 특성 결과, 종말속도는 콩의 경우 4.4∼6.0 m/s, 커피는 3.2∼4.4 m/s, 아몬드는 3.5∼5.1 m/s, 옥수수는 4.7∼6.0 m/s의 범위로 나타났다.

Fishing experiments were carried out in the adjacent sea of Yeongil Bay, the eastern cost of Korea from 2003 to 2004 using the dome-shaped pots with different five mesh sizes (17.1, 24.8, 35.3, 39.8, and 48.3mm) in order to determine the size selectivity of pots for the whelk, Buccinum opisthoplectum. The catch species were composed of Buccinum opisthoplectum (45.4%), Buccinum striatissimum (30.1%), Pandalopsis japonica (9.3%), Chionoecetes opilio (8.9%), and so on. The shell height (l) of Buccinum opisthoplectum caught in the experimental fishing pots was measured. The SELECT (Share Each Length's Catch Total) analysis method was applied with fishing data to obtain master selection curve. The model with the estimated split parameter was found to fit the catch data best. The master selection curve was estimated to be s (R)〓exp (7.833R-10.871)/[1 + exp (7.833R-10.871], where R is the ratio of shell height to mesh size. The relative shell length for 50% retention was 1.388, and the selection range was 0.281. It means that the pots of larger mesh size allow more whelks of small size to escape.

The mesh selectivity of the gillnet for Pacific herring (Clupea pallasii) was examined in field experiments with four different mesh sizes (63, 69, 75 and 81mm) from June to July, 2013 in the coastal areas of Imwon in Gangwon province. The fishing performance tests were conducted with a commercial Pacific herring gillnet and a biodegradable gillnet for Pacific herring together selectivity tests. The filed tests were carried out the total 11 times. The master curve of selectivity was estimated by the extended Kitahara's method. In the results, the catch number of Pacific herring was 9,409 (2,203kg) and occupied 84.2% in total catches weight. The optimal mesh size for 50% retention on first maturity size (female, 250mm) of Pacific herring was estimated as 64.5mm by master selectivity curves. The fishing performance of the biodegradable gillnet was showed to be equivalent with commercial gill for Pacific herring.

ZnO nanoparticles in the size range from 5 to 15 nm were prepared by zinc-lithium-acetate system. The morphologies and structures of ZnO were characterized by TEM, XRD and FT-IR spectra. UV-visible results shows that the absorption of ZnO nanoparticles is blue shifted with decrease in particles size. Furthermore, photoluminescence spectra of the ZnO nanoparticles were also investigated. The ZnO nanoparticles have strong visible-emission intensity and their intensities depend upon size of ZnO nanoparticles.

In this study, we fabricated Nd2Fe14B hard magnetic powders with various sizes via spray drying combined with reduction-diffusion process. Spray drying is widely used to produce nearly spherical particles that are relatively homogeneous. Thus, the precursor particles were prepared by spray drying using the aqueous solution containing Nd salts, Fe salts and boric acid with the target stoichiometric composition of Nd2Fe14B. The mean particle sizes of the spray-dried powders are in the range from one to seven micrometer, which are adjusted by controlling the concentra- tions of precursor solutions. After debinding the as-prepared precursor particles, ball milling was also conducted to con- trol the particle sizes of Nd-Fe-B oxide powders. The resulting particles with different sizes were subjected to subsequent treatments including hydrogen reduction, Ca reduction and washing for CaO removal. The size effect of Nd-Fe-B oxide particles on the formation of Nd2Fe14B phase and magnetic properties was investigated.

The chigger mite, Leptotrombidium pallidum, is widely distributed throughout South Korea and is a major vector for Orientia tsutsugamushi, the causative agent of scrub typhus. In this study, the genome size of the chigger mite was estimated to determine the necessary coverage level prior to whole genome sequencing. Cloning of EF1α and RpS3 as putative single copy reference genes were conducted and their partial sequences were determined. Using the serially diluted reference genes with known amount as standard templates, the weight of a single copy of the genome was predicted by a method based on quantitative real time PCR. The average genome length estimated from the weight using two methods was 191 ± 7 Mb. When the genome size of other arthropods (Drosophila melanogster, Apis mellifera and Tetranychus urticae), with their genome analysis completed, were estimated using the same method and compared with actual values, the estimation accuracy was 79.8-98.9%, suggesting our current estimation of L. pallidum genome size is reliable. The estimated L. pallidum genome size is in a similar range to other Acariform mites, such as the dust mite and scabie mite, but appoximately 10-fold smaller compared to the deer tick, which belongs to Parasitiform. Our finding provides key information for further genome sequencing and understanding of mite genome evolution.

In this study, by using nickel chloride solution as a raw material, a nano-sized nickel oxide powder with an average particle size below 50 nm was produced by spray pyrolysis reaction. A spray pyrolysis system was specially designed and built for this study. The influence of nozzle tip size on the properties of the produced powder was examined. When the nozzle tip size was 1 mm, the particle size distribution was more uniform than when other nozzle tip sizes were used and the average particle size of the powder was about 15 nm. When the nozzle tip size increases to 2 mm, the average particle size increases to roughly 20 nm, and the particle size distribution becomes more uneven. When the tip size increases to 3 mm, particles with an average size of 25 nm and equal to or less than 10 nm coexist and the particle size distribution becomes much more uneven. When the tip size increases to 5 mm, large particles with average size of 50 nm partially exist, mostly consisting of minute particles with average sizes in the range of 15~25 nm. When the tip size increases from 1 mm to 2 mm, the XRD peak intensities greatly increase while the specific surface area decreases. When the tip size increases to 3 mm, the XRD peak intensities decrease while the specific surface area increases. When the tip size increases to 5 mm, the XRD peak intensities increase again while the specific surface area decreases.

Fly ash is one of the aluminosilicate sources used for the synthesis of geopolymers. The particle size distribution of fly ash and the content of unburned carbon residue are known to affect the compressive strength of geopolymers. In this study, the effects of particle size and unburned carbon content of fly ash on the compressive strength of geopolymers have been studied over a compositional range in geopolymer gels. Unburned carbon was effectively separated in the -46μm fraction using an air classifier and the fixed carbon content declined from 3.04 wt% to 0.06 wt%. The mean particle size (d50) decreased from 22.17μm to 10.79μm. Size separation of fly ash by air classification resulted in reduced particle size and carbon residue content with a collateral increase in reactivity with alkali activators. Geopolymers produced from carbon-free ash, which was separated by air classification, developed up to 50 % higher compressive strength compared to geopolymers synthesized from raw ash. It was presumed that porous carbon particles hinder geopolymerization by trapping vitreous spheres in the pores of carbon particles and allowing them to remain intact in spite of alkaline attack. The microstructure of the geopolymers did not vary considerably with compressive strength, but the highest connectivity of the geopolymer gel network was achieved when the Si/Al ratio of the geopolymer gel was 5.0.

본 실험은 토마토 플러그묘 생산에서 공간처리와 배지 부피처리를 함께하여 두 가지 처리가 유묘의 묘소질 및 수확량에 미치는 영향을 구명하고자 수행하였다. 처리는 공간과 배지의 부피별로 각 2처리, 모두 4가지 처리를 두었다. 배지는 동일하되 배지의 부피에 따라 40공과 50공 플러그 육묘판을 사용했고, 각 육묘판에 공간처리를 한 것과 하지 않은 것으로 나누어 처리했다(40S-OK, 40SNO, 50S-OK, 50S-NO). 전 실험기간 중에 처리외의 환경 조건과 급액조건은 모두 동일하게 적용하였다. 광합성 속도와 묘소질 분석 및 수확량과 수확속도 모두에서 통계적 유의성이 있게 공간처리와 배지의 부피 처리의 영향을 받았다. 광합성 속도와 묘소질에서는 40S-OK, 50S-OK, 40S-NO, 50S-NO 처리 순으로 좋은 결과를 나타내어 공간처리의 효과가 더 크고, 수확량에 서는 40S-OK, 40S-NO, 50S-OK, 50S-NO 처리 순으로 많아서 배지의 부피 처리의 영향이 큰 것으로 판단된다. 따라서 고품질 묘 생산과 초기 수확량을 증대하고, 수확 속도를 빠르게 하기 위해서는 육묘기에 적절한 공간확보와 배지의 부피를 크게 하는 것이 효과적인 것으로 사료된다.

This paper deals with the picking batch size which a bi-directional carousel system can be feasible. The items that customers order are retrieved from the bins of carousel with batch size. The mathematical equations representing rotary travel distance and retrieval lead time to pick a given batch size are derived. Rotary travel distance represents the distance which carousel system rotates to retrieve items in a batch. The bi-directional carousel system rotates to minimize the travel distance in retrieving the items in a batch. Rotary travel distance and retrieval lead time are analyzed for the batch size through the simulation approach. From the simulation, the retrieval batch size that carousel system can be feasible is obtained. A numerical example is shown to explain the solution procedure.