Segregation Charging Behavior of Ultra‑Fine Iron Ore Briquette in Sinter Feed Bed: DEM Analysis

Kang‑Min Kim,Jong‑Ho Bae,Jong‑In Park,Jeong‑Whan Han 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.8

The sinter–briquette complex firing process which is an effective technology for utilization of low grade ultra-fine ore is amethod for charging sinter feed mixed with briquette made of ultra-fine ore. To uniformly fire briquettes using the excessheat from the lower part of the sinter feed bed, they must be segregated in that region. In this study, the particle propertiesand interaction coefficients of real samples were measured and used for a numerical analysis. Furthermore, a discrete elementmethod simulation was used to investigate the characteristics of the sinter feed and briquette charging process, namelyburden distribution and porosity, by varying the shape and mixing ratio of the briquette. The results showed the while theshape of the briquette did not affect the burden distribution and porosity, the porosity at the lower part of the bed proportionallyincreased with the briquette mixing ratio. Furthermore, it was observed that to achieve optimized heat distribution ofthe bed, the proportion of briquette in the charging mixture should be more than 20%.

정부원가계산제도의 개선방안에 관한 연구

배병한,강호영 경북대학교 산업기술연구소 1995 産業技術硏究誌 Vol.23 No.-

원가계산에 의한 예정가격의 결정은 매년 증대되어 오고 있으며, 최근 우리나라 전체 계약건수의 70%를 차지하고 있다. 이는 정보물자 조달에 있어 정부원가계산서비스가 어느 정도 중요한 역할을 담당하고 있는지를 단적으로 증명하는 것이다. 정부원가계산서비스가 일정한 품질수준을 유지하지 못할 경우 실무수행상 야기되는 정보위험에 직면할 수 밖에 없으며, 결과적으로 정부예산의 비능률적 집행을 초래하게 된다. 그러나, 정부원가계산제도가 지니고 있는 중요성에도 불구하고 아직까지 우리나라에서는 체계적인 연구가 극히 부족한 실정이다. 본 연구는 이러한 제반 여건을 고려하여 우리나라 정부원가계산서비스의 품질수준에 영향을 미치는 주요 변수에 대한 문헌 및 실증분석을 통해 문제점 및 개선방안을 제시하려는 목적을 지니고 있다. 이와 같은 연구목적을 효과적으로 달성하기 위하여 본 논문에서는 (1)정부원가계산용역기관 지정 및 조사·지도제도에 대한 현황분석을 통하여 문제점을 도출하고 이에 대한 개선방안을 제시하였으며, (2)정부원가계산 용역계약제도의 현황분석을 통한 문제점 도출과 개선방안을 제시하였으며, (3)부실 정부원가계산서비스에 대한 법적책임의 소재 및 범위에 대한 현황분석을 통해 문제점을 도출하고 개선방안을 제시하였으며, (4) 원가계산에 의한 예정가격작성준칙 중 제조 및 공사원가계산 기준과 관련된 제반 문제점 분석 및 개선방안을 제시하였다. 이상 언급한 연구내용에 대한 방법으로는 문헌연구와 실증연구를 병행하였다. 즉, 우리나라 정부원가계산제도의 현황분석과 문제점 도출을 위해 설문 및 관련문헌의 조사연구를 병행하는 동시 개선방안을 모색하기 위해서 설문 및 면담조사를 병행하였다. 본 연구에서 제시하고 있는 정부원가계산제도의 문제점과 개선방안 제시는 우리나라 정부원가계산제도의 발전방향을 모색하는데 있어 하나의 과제를 제시하고 있다는 차원에서 그 의의를 찾을 수 있다. Government Costing Service is very important role which performs supply and demand of goods in government. Therefore, quality of government costing service is directly related on efficient performance of governmental budget. This study is focused on extracting principal problems through analisis of main factors which are influencing quality of government costing service. Simultaneously, this paper shows dirction of improvement in government costing service which depends on our practical experience for a few years. Although government costing system is established by laws, it can not be ensured from laws. Above all things, development of government costing system can be achieved by active effort and wisdom in government management department, service trust agency and service execution agency.

STS 304 강의 용접부에 미치는 전자선 조사의 영향

裵東樹,鄭鎬信,姜昌龍 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.4

The heat affected zone(HAZ) and matrix of a welded STS 304 steel have been irradiated in an 1250 keV high voltage electron microscope at 673 K and up to 5.4 dpa(displacements per atom) to study the effect of electronbeam irradiation on the microstructure. In-situ observation showed that the voids formed by electron-beam irradiation coalescenced and grew to larger void with irradiation dose. Values of void size, void number density and void swelling percentage in HAZ were greater than those of matrix, and these were increased and then saturated gradually with irradiation dose. Non-equilibrium segregation phenomena such as Cr depletion and Ni enrichment were also observed in both the HAZ and matrix of welded STS304 steel at the grain boundary.

고 Mn-Cr 강의 조사손상에 미치는 전자선 조사 온도의 영향

배동수,정호신,강창용,남승훈,이해무 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.3

The effect of electron-beam irradiation temperature on irradiation damage of 12%Cr-15%Mn austenitic steel for structural material of nuclear and/or fusion reactors from the point of view of the reduced activation was investigated by using the 1,250 keV HVEM and an energy dispersed X-ray analyzer(EDX) in a 200 keV FE-TEM with beam diameter of about 0.5 nm. Void formation was not observed in irradiated specimen. The dislocation loop growth was observed and the density and size of dislocation loop were increased with irradiation dose. Irradiation-induced segregations of Cr and Mn at grain boundary were also observed by electron-beam irradiation condition. The amount of Mn segregation was increased with irradiation temperature, however, segregation phenomenon was disappeared in the case of Cr.

Competition Responses of Populus alba Clone ‘Bolleana’ to red:far-red light

Bae,Han-hong,Kang,Ho-duck,Richard B,Hall 한국자원식물학회 2004 Plant Resources Vol.7 No.1

The reduced ratio of red:far-red (R:FR) light acts as a measure of the proximity of competitors and plants can detect the potentially competing neighbor plants by perceiving reflected R:FR signals and initiate the response of “shade avoidance” before actual shading occurs. The phytochrome system is responsible for monitoring the changes in the R:FR and initiating the shade avoidance response. The response to low R:FR ratio was studied in a white aspen Populus alba clone ‘Bolleana’ using two filter systems: a clear plastic filter system that allows a R:FR ratio less than 1.0 to pass from adjacent border plant reflection; and a special commercial plastic that blocks FR light and creates a R:FR ratio above 3.0. The reduced R:FR signals enhanced the stem elongation in response to competition at the expense of relative stem diameter growth. Trees grown inside clear chambers were 27 % taller than trees grown inside the FR-blocking filter chambers. Stem taper of clear chamber trees was 16% less than the FR-blocking filter trees. Low R:FR also induced 22% more stem dry weight and 13% greater petiole length per leaf compared to the FR-blocking filter trees. There were no statistically significant differences in leaf area, leaf number increment, and total dry weight between the two light filter treatments.

漁貝類의 色素에 關한 硏究 : 1. 진주담치의 CAROTENOID 1. Carotenoids in Sea Mussel, Mytilus edulis

金鐘培,李康鎬 釜山水産大學校 1971 釜山水産大學 硏究報告 Vol.11 No.1

In this study, Carotenoids of the sea mussel, Mytilus edulis, were separated on micro-cel C column and thin layer slides, and analyzed by spectrophotometry. In case of column chromatography, pigments were separated with acetone-petroleum ether solution, starting with 7% and ending with 20%. The separation was fairly good although some xanthophylls remained inseparated on the top of the column. On the micro-cel C thin layer slide, however, they were easily separated by the mixture solvent of dichloromethane, ethylacetate, and acetone(14:5:1:v/v). From the results, beta-carotene, lutein, zeaxanthin, and astacene were identified and a band was assumed mytiloxanthin. Some other bands were also isolated but remained unindentified because their spectral data and chromatographic behaviour were often unidentical comparing that of authentic pigments. The results also suggested that xanthophylls or their esters are dominant in sea mussel whereas carotenes are minor in both variety and quantity.

AHP를 이용한 전자경비 시스템의 평가에 관한 연구

정호원,강인배 한국경영과학회 1996 經營 科學 Vol.13 No.2

The use of advanced electronic security system is growing quickly to protect properties and life. However, customers cannot select appropriate configuration of the system because there are no objective evaluation methods to measure the security ability of the system. Furthermore, the system suppliers cannot propose quantitative value of security ability of the system. This study suggests an objective evaluation and selection method that customers and suppliers can use to base his or her decision when choosing the most appropriate configuration of the system. Our method identifies 6 characteristics and 20 sub-characteristics of the electronic security system, calculates their weights, and decides the best configuration. We use AHP(Analytic Hierarchy Process) to assign the weights of characteristics. Finally, this paper gives an example to compare four alternative configurations of the system.

친수성으로 표면개질한 폴리설폰막의 투과플럭스

송근호,김강희,조성헌,이광래,임종호,배성수 한국화학공학회 2004 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.42 No.1

실관막형 폴리설폰 막의 표면을 2-hydroxyethylmethacrylate(HEMA)로 코팅하였으며, 코팅인자들인 azobisisobutyronitrile(AIBN)/HEMA 성분비, 용매의 종류(물, 메탄올), UV 조사시간 등이 투과플럭스에 미치는 영향을 조사하였다. AIBN/HEMA/ 메탄온ㄹ 용액으로 코팅한 막이 AIBN/HEMA 성분비가 높고, UV 조사시간이 길수록 투과플럭스가 높았다. AIBN/HEMA 성분비가 낮으면 동일한 투과플럭스를 얻기 위하여 UV조사시간을 더 길게 하여야 하며, 특정한 AIBN/HEMA 성분비와 UV 조사시간에서 코팅한 막의 투과플럭스는 원래의 막(코팅하지 않은 막)보다 높게 나타났다. 또한, 오일에멀젼에 의한 fouling은 코팅한 막과 원래의 막에 모두 나타났지만, 코팅한 막의 fouling이 원래의 막 보다 현저히 낮았다. 즉, fouling 발생 후 코팅한 막의 수투과 플럭스(0.2683g/㎠ㆍmin)는 코팅하지 않은 막(0..448g/㎠ㆍmin)보다 약 6배 이상으로 높게 유지되었다. A hollow-fiber type polysulfone UF membrane was surface-coated with 2-hydroxyethylmethacrylate(HEMA). The effect of various coating paramters on permeation flux was investigated, such as concentration ratio of Azobisisobutyronitrile(AIBN)/HEMA, solvent (water or methanol), and UV irradiation time. The membrane coated with a solution of AIBN/HEMA/methanol showed about 2.65 times higher water flux than that coated with a solution of AIBN/HEMA/water. The membrane coated with a solution of higher AIBN/HEMA ratio and a longer UV irradiation time exhibited a higher permeation flux. The membrane coated with a solution of lower AIBN/HEMA ratio needed a longer UV irradiation time for coating to get a same level of permeation flux. In order to have a greater permeation flux than uncoated membrane, the membrane should be coated with a solution of a certain AIBN/HEMA ratio and UV irradiation time. The fouling by oil emulsion occurred to both of the coated and the uncoated membrane. However, the fouling of coated membrane was much less than uncoated one; the water flux(0.2683g/㎠·min)through the coated membrane was about 6 times higher than that(0.0558g/㎠·min) through the uncoated membrane.

팔영산 삼림식생과 토양환경

이호준,김종홍,배병호,박문수,전영문,강재구,신정식 建國大學校基礎科學硏究所 1997 理學論集 Vol.22 No.-

전라남도 고흥군 소재 팔영산 (608.6 m) 일대의 삼림군락에 대한 색생조사를 1993년 10월부터 1995년 7월까지 실시하였다. 조사한 자료는 Z-M 방식에 의해 종조성표를 작성하였다. 이에 따라 삼림군락은 신갈나무군락, 졸참나무군락, 굴참나무군락, 서어나무군락, 소나무군락등 5 개 군락으로 분류되었다. 입지와 환경과의 유기적 관계를 조사하기 위해 토양을 분석한 결과, 신갈나무군락은 토양의 비옥도가 높은 산의 능선 부위에 집중 분포하였으며, 굴참나무군락과 소나무군락은 토양의 비옥도가 낮고 비교적 건조한 고도 400 m 이하 지역에 주로 군락을 형성하고 있었다. 또한 졸참나무군락은 고도 300 - 550 m 이내에서 부분적으로 나타났으며, 서어나무군락은 토양의 비옥도가 양호한 고도 300 - 550 m 사이의 골짜기 주변에 국지적으로 분포하였다. 팔영산 삼림식생의 특징은 상록활엽수림이 형성될 수 있는 지역이나 후박나무, 동백나무, 사스레피나무 등의 몇몇 종을 제외하고는 상록활엽수의 분포를 확인할 수 없었으며, 일부 식재림을 제외한 대부분의 지역이 낙엽활엽수와 소나무의 혼효림으로 구성되어 있었다. The phytosociological study forest vegetation on Mt. Palyoung (608.6 m) was investigated from October 1993 to July 1995 in Koheug-Gun, Cheonnam province. According to Z-M method, the floristic composition table of the forest vegetation was divided into five community as follows; Quercus mongolica community, Quercus serrata community, Quercus variabilis community, Pinus densiflora community, Carpinus laxiflora community. The soil was analyzed to investigated the soil conditions and soil fertility. As a result, the organic matters which showing soil fertility were found to be low Quercus variabilis and Pinus densiflora community at comparatively xerophic conditions, below 400 m altitude, while they were increased in Quercus mongolica community on mountain ridge, and that Quercus serrata community was appeared 300-550 m altitude around mountain stream to moderate soilfertility. The forest vegetation of Mt. Palyoung area unconfirmed capable of evergreen broad-leaved forest, but appeared to Machilus thunbergii, Camellia japonica and Eurya japonica species etc. On the other hand, surveyed site's vegetation was distributed mixed forest of deciduous leaved forest and Pinus desiflora, except for some afforestation.

VDT작업별 정신사회적 스트레스와 근골격계 장애에 관한 연구

백남종,강종두,주영수,배인근,권호장,박종만,조수헌,김돈규,김재용,최홍렬 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.4

It has been hypothesized that jobs that have both high psychological demands and low decision latitude("job strain") can lead to musculoskeletal disorder. The objective of this study was to test whether job strain was correlated with the presence of work-related musculoskeletal disorder, especially myofascial pain syndrome(MPS). Information on demographic factors, confounders such as household load and taking care of children or not, and scores for decision latitude, job demand, and social support was obtained by self-administered questionnaire, which had been developed in Korean language, by adopting NIOSH instrument and Extended Karasek Model(16 items). All subjects were also examined by rehabilitation medicine specialists for musculoskeletal disorders. Subjects(n=370) could be categorized into 4 groups, these were, housewives(n=89), shipyard CAD workers(n=89), general female workers(n=79; nurses, insurance counselors, public officials, clerks, etc), and telephone directory assistance operators(n=113). Results from univariate analyses indicated that all demographic factors, all confounders, scores for decision latitude and social support were not associated with the risk of musculoskeletal disorder. However, score for job demand was higher in musculoskeletal disorder cases than others. In subgroup analysis, this association was convinced again, in telephone directory assistance operators. Job strain model showed that the group of telephone directory assistance operators was high-stain group, and OR of musculo skeletal disorder was 2.446(95% C. I. : 1.174, 5.096), when comparing this with the low strain group. In conclusion, job strain is a risk factor for work-related musculoskeletal disorder.