• 한국정밀공학회지
• /
• 제12권10호
• /
• pp.78-88
• /
• 1995

For producing iron or steel products with good quality, the concentration of the material components should be analyzed quickly with high relability using XRF(Fluorescent X-Ray Spectrometer). Since the analysis results are much dependent upon the surface con- dition, the samples have to be prepared to have good test condition. This study presents an image processing system for inspecting the surface condition of the iron test sample. In order to use thd computer vision system, we need to develop a lighting device and image processing algorithm. For the adequate lighting device of inspection system, the indirect lighting device is contrived to cut the external light and provide uniform, stable and cold light. The image processing algorithm is aimed to reduce inspection time and to get similar analyzing results to those of the experienced operators. At first, the image processing algorithm checks whether the surface of the iron sample is ground well or not. Then, the defects; hole or dig are conted and surface condition is evaluated. In addition, the algorithm gives the reliability of the analyzing results in order to help operator's decision.

• 전기학회논문지P
• /
• 제58권2호
• /
• pp.190-195
• /
• 2009

Thin-gauged 3% silicon steel sheets having a highly grain-oriented texture have been developed as a core material for applications of middle-frequency (400 Hz ${\sim}$ 10 kHz) devices. The newly developed sheets with a tension coating showed an excellent reduction in iron loss at 400 Hz (iron loss at 1.0 T and 400 Hz = 4.677 W/kg, iron loss at 1.5 T and 400 Hz = 9.742 W/kg) due to high magnetic induction, $B_{10}$(measured induction at 1000 A/m), of over 1.9 T. In cases of frequencies below 400 Hz, magnetic induction, $B_{10}$, of the sample plays a major role to reduce its iron loss as excitation induction increases, whereas, in case of frequency of 1 kHz, thickness dependence becomes dominant due to a lower iron loss at relatively thinner sample. The sheets with a high magnetic induction, therefore, are favorable for high excitation induction (over 1.0 T) and low excitation frequency (below 400 Hz) applications, whereas the sheets that can reduce eddy current loss by reducing thickness or domain wall width are advantageous for low excitation induction (below 1.0 T) and high excitation frequency (around 1 kHz) applications.

• 한국주조공학회지
• /
• 제24권1호
• /
• pp.52-59
• /
• 2004

Microstructure and mechanical properties of ductile cast iron were investigated in terms of diameter change of samples that gives rise to modify the microstructure due to different cooling rate in the continuous casting process. The chemical composition used in this study was GCD 400 grade. From the microstructural observation, we have found a large number of graphite with small size in diameter which is comparable to the microstructure of the sample produced by conventional sand casting. The major reason of this would he due to high cooling rate. In the sample with 26 mm in diameter, the microstructure was composed of pearlite, iron carbide, and graphite. In the samples with 60 and 100 mm in diameter, however, we have observed a dissimilar microstructure that consisting of ferrite and graphite. Concerning the mechanical property, the sample with 26 mm in diameter showed higher hardness and strength compared to those samples with 60 and 100 mm in diameter. The result obtained for ductility appeared a reversal. Much more works such as inoculation, process design and chemical composition would be required in order to have a sound product even in a small diameter of samples.

• 자원환경지질
• /
• 제12권1호
• /
• pp.13-15
• /
• 1979

Iron ore waste discarded around Choong-ju iron district, Choongchong-Bukdo is as low as 25 per cent of iron, mainly consisting of hematite and magnetite. In this mineral dressing test procedure 93 per cent of magnetite was separated and concentrated into the magnetite concentrate as high as 62 per cent. The remaining sample, mostly, hematite averages about 19.8 per cent of iron which can be concentrated with very good results with the optimum flotation conditioning-pH 3.0 and 3 cc per litre of aero-promoter #845 (0.5% sol.) and 1.5cc per litre of hydro-fluoric acid (40% sol.) and four times of cleaning flotation. Hematite concentrate averages 64.2 per cent of iron. The overall iron concentrate averages 63 per cent of iron with recovery 86 per cent of iron contained.

• 보존과학회지
• /
• 제30권1호
• /
• pp.27-32
• /
• 2014

본 논문에서 보존처리 한 책은 1935년 일본사에서 발행된 "위인최후(偉人最後)の언엽집(言葉集)"이다. 1900년대 초반의 책들은 대부분이 산성지로 되어있어 책의 산도가 높고 스테이플로 인한 갈변현상이 심하다. 본 시료도 갈변현상이 관찰되었으며, 책의 pH가 3.2로 매우 낮았다. 스테이플에 의한 갈변 이외에 종이 전체의 색이 많이 변하였으며, 종이 자체의 산성도로 인하여 종이가 바스러지는 현상이 보였다. 스테이플 철심을 제거한 후 건식, 습식클리닝을 행하여 오염물을 제거하였다. 가볍게 프레스하여 종이를 건조시킨 후, 미농지($4g/m^2$)를 사용하여 속지와 겉 표지를 배접하여 보강처리를 하였다. 본 논문에서는 스테이플 심을 대신하여 실이나 종이로 다시 묶는 기존의 보존처리 방법과 다르게 기존의 스테이플과 유사한 철심을 만들어 원래의 자리에 복원하는 작업을 하였다. 복원 하기 위해 스테이플의 두께와 비슷한 철사를 사용하였고, 착색액 ($H_2O$, $C_2H_5OH$, $CuSO_4{\cdot}5H_2O$, $FeCl_3{\cdot}6H_2O$)에 넣어 부식된 스테이플 심과 유사한 색으로 착색하였다. 마지막으로 20%의 paraloid B-72로 방식처리를 하여 차후의 부식을 예방하였다.

• Journal of Nutrition and Health
• /
• 제26권6호
• /
• pp.692-702
• /
• 1993

To evaluate iron nutritional status and to compare biochemical indices used for evaluation of iron nutriture, fasting blood sample was taken from 96 Korean female college student and hemoglobin(Hb) concentration, hematocrit(Hct), serum iron, total iron binding capacity(TIBC) and serum ferritin concentration were measured and transferrin(TF) saturation was calculated. Prevalence of iron deficiency varied from 4.2% when judged from Hb concentration and Hct to 38.5% and 40.6% when TIBC and serum ferritin concentration were used. TIBC was negatively correlated with serum ferritin(r=0.4561, p<0.001), while other indices showed positive but less significant correlations(p<0.05). Regarding iron status judged by serum ferritin was regarded as true iron status, the present cutoff points of Hb, Hct, serum iron, TF saturation were very insensitive in identifying the subjects with iron deficiency. Only TIBC was suitable for detecting iron deficiency in the study subjects. It is concluded from the study results that iron deficiency in young Korean adult women would be significantly underestimated with presently used biochemical measurements except TIBC and new cutoff points of these indices were proposed based on sensitivity, specificity measured prevalence, and positive and negative predictive values.

• Nuclear Engineering and Technology
• /
• 제53권5호
• /
• pp.1619-1625
• /
• 2021

This paper demonstrates the possible nondestructive analysis of iron artifacts' metallurgical characteristics using neutron imaging. Ancient kingdoms of the Korean Peninsula used a direct smelting process for ore smelting and iron bloom production; however, the use of iron blooms was difficult because of their low strength and purity. For reinforcement, iron ingots were produced through refining and forge welding, which then underwent various processes to create different iron goods. To demonstrate the potential analysis using neutron imaging, while ensuring artifacts' safety, a sand iron ingot (SI-I) produced using ancient traditional iron making techniques and a sand iron knife (SI-K) made of SI-I were selected. SI-I was cut into 9 cm², whereas the entirety of SI-K was preserved for analysis. SI-I was found to have an average grain size of 3 ㎛, with observed α-Fe (ferrite) and pearlite with a body-centered cubic (BCC) lattice structure. SI-K had a grain size of 1-3 ㎛, α-Ferrite on its backside, and martensite with a body-centered tetragonal (BCT) structure on its blade. Results show that the sample's metallurgical characteristics can be identified through neutron imaging only, without losing any part of the valuable artifacts, indicating applicability to cultural artifacts requiring complete preservation.

• 한국주조공학회지
• /
• 제5권3호
• /
• pp.5-12
• /
• 1985

Many researchers have studied the eutectic solidification of CV Graphite Cast Iron qualitatively. However quantative studies have not been done. The type of eutectic solidification of CV Graphite Cast Iron treated with CG Alloy (Fe-Si-Mg-5Ti-Ca-Ce) was studied quantitatively through M.D.E. value (Mushy Degree of Eutectic Solidification) = $t_2/t_1)$, where $t_1$ is the difference of the eutectic solidification starting time between surface and center part of the casting sample, and $t_2$ is the time of eutectic solidification of the center part. Following results were obtained. (1) The M.D.E. value of CV graphite cast iron lies between that of spheroidal graphite and that of flake graphite cast iron but is closer to that of Flake graphite cast iron. (2) The M.D.E. value of CV graphite cast iron depends upon CV ratio. (3) The time required for eutectic solidification increases as graphite form is changed from Flake, CV. to spheroidal graphite. (4) The M.D.E. value increases as cooling rate increases.

• 한국세라믹학회지
• /
• 제27권6호
• /
• pp.769-776
• /
• 1990

This study deals with the refinement of Hwasun flint clay by grinding, classifying, magnetic separation and acid treatment in sequence. Results are as follows ; 1. Fine kaolinite particles of median size in the range of 4.8 and 1.7$\mu\textrm{m}$ was collected, with the yield of 87.4% by dry grinding and classifying process. 2. It is proven that the iron bearing are of Hwasun flint clay is mainly consisted of chloritoid and iron rich muscovite. 3. As the results of the high gradient magnetic separation, the bleaching and iron removal degree of the dry grinding and classifying sample was 4-58% and 5-62% respectively. 4. As the results of the acid treatment, bleaching and weight loss degree of the dry grinding and classifying sample was reduced to 16-82% and 6-29% respectively.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권4호
• /
• pp.581-587
• /
• 2003

This study was designed to examine the effect of icroencapsulated iron fortified drink yogurt and vitamin C as a bioavailable helper of iron on chemical and sensory aspects during 20 d storage. Coating material was polyglycerol monostearate (PGMS), and ferric ammonium sulfate and vit C were selected as core materials. The highest efficiency of microencapsulation of iron and vit C were 73% and 95%, respectively, with 5:1:50 ratio (w/w/v) as coating to core material to distilled water. Iron fortification did not affect the fermentation time required for the drink yogurt to reach pH 4.2. The addition of uncapsulated iron decreased the pH during storage. TBA absorbance was significantly lower in capsulated treatments than in uncapsulated treatments during storage. In sensory aspect, the yogurt sample added with uncapsulated iron and vit C, regardless of capsulation, showed a significantly high score of astringency, compared with those of control and other groups. A significantly strong sourness was observed in treatment containing capsulated iron and uncapsulated vitamin C at every time interval. The present study provides evidence that microencapsulation of iron with PGMS is effective for iron fortification in drink yogurt.