• Resources Recycling
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• v.1 no.1
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• pp.69-77
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• 1992

In this study, a talc flotation was fundamentally carried out with dolomite origin talc ore produced in Dong Yang Talc Mine at Chung-Ju. This ores are mainly composed with talc as a valuable mineral, dolomite as a gangue mineral and other minor minerals of hornblende, tremolite, actinolite, chlorite, calcite, epidote and iron oxide. In order to obtain some of fundamental data for the talc flotation from low grade dolomitic talc tailings which were abandoned -25mm +17 mm size, after the treatment of crude talc ores by screening and hand -picking at the mine, flotation characteristics of the pure talc and dolomite in this ores were first investigated by measuring floatability of the minerals at some experiment conditions. Furthermore, Several times of batch flotations for talc were performed experimentally to recover talc from the low grade dolomitic talc tailings. From the results obtained in this experiment, the conclusions can be summarized as follows ; 1) In the flotation of pure talc, the use of Dowfroth 250 as frother was the most effective in various kinds of frother and the proper addition amount was about 50 mg/${\ulcorner}$(200g/t) at the condition of this experiment. 2) In the flotation of pure talc, the use of kerosene as collector was not adequate, at the addition over 50mg/l of Dowfroth 250. 3) The adequate pH of pulp ranged from pH6 to pH9 in the talc flotation using Dowfroth 250 as frother. 4) The use of Quebracho as depressant for dolomite was not adequate for the recovery of talc, and more selective depressant was required. 5) In the talc flotation on D sample(dolomitic talc tailing), the suitable number of cleaning time was about 3. 6) At this experimental conditions for the talc flotation on D sample, the talc flotation concentrates of 1. 40% CaO and 84.5 whiteness could be recovered with the talc recovery of about 53%.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.635-641
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• 2014

Archaeological waterlogged woods require a process of dimensional stabilization for their conservation. PEG is the most widely used in the conservation of archaeological waterlogged wood. One of the easiest and commonly used methods is the impregnation of 40% polyethylene glycol followed by vacuum freeze drying. However, the waste fluid produced from the PEG treatment is black in color and has a severe odor due to the organic matter extracted from the wood. Thus It cannot be recycled and it was just thrown out. Color of waste fluid can be decolored with oxidation reaction by hydrogen peroxide. Properties of PEG before and after preservation treatment, and after oxidation with $H_2O_2$ were not changed. Dimensional stability of archaeological waterlogged Salix koreensis Andersson was studied with pure or recycled PEG. The ratio of impregnation solutions were 10:0, 7:3, 5:5, 3:7, 0:10 (pure PEG : recycled PEG). Impregnation process was carried out by putting the wood specimens 10% PEG solution for 5days, 20% for 5 days, 30% for 5 days finally 40% for 5 days. All of the specimens showed the weight change rate of 25%. SEM results provided that the dimensional change of were less than 4% PEG impregnated specimens. Comparing with pure PEG impregnation system, conservation precess mixed PEG also showed no significant changes. Conclusively, the recycled PEG can be used for archeological waterlogged wood conservation precess.

• Archives of design research
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• v.12 no.3
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• pp.29-40
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• 1999

Walter Gropius, famous architect of Bauhaus, once treated of pure mind which was revealed in the system of object and its phenomena through sense of sight while examining material being and illusive being. And Thomas Aquinas said that man can have a creative power only with modest mental state void of prejudice saying that he expected God to come to him after his soul went out of him. The same thing was said by so many great philosophers and thinkers other than him. I think his saying, "God comes after Soul's escape from the body for a new creation", has a real truth for all times and places and beauty itself beyond expression. Why\ulcorner The reason why the saying is so true is because it has a Yin and Yang Idea, that is, the Soul means a dark spirit correspondent to Yin between both oriental ideas and God does a bright spirit correspondent to Yang between them. By reason of this idea, I would like to assert that we should take it granted that we stand in need of the same bright Yang's spirit as God has for the new creation, and let the Yang's bright spirit come to our minds. We can call it divine 'Providence', or call it God's guidance, which we cannot help accepting as a man's fatality. As God was pleased after he made man and all the creatures by dint of his design, so man was pleased after he made everything he needed by the same design that he accepted from God. In spite of pleasure of different dimensions from what God and Man has each other, their way of empathies were all the same. In this paper I compared a worldly lower conception by which man designed his products for his sensuous satisfaction with a higher conception by which God designed his creatures for his mental satisfaction. I intended to infer what destined relation there must be between both God's and man's creations, trying to remind designers that they have to confess to have not so divine a providence as God has for creation because I think the real truth is that they had regarded their works of product design as a routine occurrence for their physical convenience in the industrial plans.ial plans.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.75-80
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• 2006

The effective thermal conductivities of $Mm(La_{0.6-0.8})Ni_{4.0}Co_{0.6}Mn_{0.2}Al_{0.2}$ [TL-492] with hydrogen and helium have been examined. Experiment results show that pressure has great influence on effective thermal conductivity in low pressure range [below 0.5 MPa]. And that influence decreases rapidly with increase of gas pressure. The reason is at low pressure, the mean free path of gas becomes greater than effective thickness of gas film which is important to the heat transfer mechanism in this research. And, carbon fibers have been used to try to enhance the poor thermal conductivity of TL-492. Three types of carbon fibers and three mass fractions have been examined and compared. Naturally, the highest effective thermal conductivity has been reached with carbon fiber which has highest thermal conductivity, and highest mass fraction. This method has acquired 4.33 times higher thermal conductivity than pure metal hydrides with quite low quantity of additives, only 0.99 wt% of carbon fiber. This is a good result comparing to other method which can reach higher effective thermal conductivity but needs much higher mass fraction of additives too.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.4
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• pp.185-189
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• 2004

The temporal variation of a secondary electron emission coefficient (${\gamma}$ coefficient) of hydrogenated amorphous silicon (a-Si:H) was investigated in a dc silane plasma. Estimated ${\gamma}$ coefficients have a value of 2.73 ${\times}$ 10$^{-2}$ on the pure aluminum electrode and 1.5 ${\times}$ 10$^{-3}$ after 2 hours deposition of -Si:H thin films on a cathode. It showed an abrupt decrease for about 30 minutes before saturation. The variation of the ${\gamma}$ coefficient was estimated as a function of the thin film thickness, and the film thickness was about 80 nm after 30 minutes deposition time. These results are compared with the results of a computer simulation for ion penetration into a cathode.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.2
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• pp.79-83
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• 2000

A han transfers her serum immunoglobulin G to the agg (IgY) and gives immunity to her offspring. Therefore, The hen agg can be an effective supplier of a large amount of antigen specific antibody that accumulates in the egg yolk. Antigen specific antibody has been widely used for immunological analysis in the field of diagnosis as well as pure scientific research. The production and separation technology of IgY is demonstrated in the present study.

• The Pure and Applied Mathematics
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• v.19 no.4
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• pp.315-325
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• 2012

Let A and B denote a point, a line or a circle, respectively. For a positive constant $a$, we examine the locus $C_{AB}$($a$) of points P whose distances from A and B are, respectively, in a constant ratio $a$. As a result, we establish some equivalent conditions for conic sections. As a byproduct, we give an easy way to plot points of conic sections exactly by a compass and a straightedge.

• ETRI Journal
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• v.22 no.2
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• pp.20-31
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• 2000

Much research on natural language processing (NLP), computational linguistics and lexicography has relied and depended on linguistic corpora. In recent years, many organizations around the world have been constructing their own large corporal to achieve corpus representativeness and/or linguistic comprehensiveness. However, there is no reliable guideline as to how large machine readable corpus resources should be compiled to develop practical NLP software and/or complete dictionaries for humans and computational use. In order to shed some new light on this issue, we shall reveal the flaws of several previous researches aiming to predict corpus size, especially those using pure regression or curve-fitting methods. To overcome these flaws, we shall contrive a new mathematical tool: a piecewise curve-fitting algorithm, and next, suggest how to determine the tolerance error of the algorithm for good prediction, using a specific corpus. Finally, we shall illustrate experimentally that the algorithm presented is valid, accurate and very reliable. We are confident that this study can contribute to solving some inherent problems of corpus linguistics, such as corpus predictability, compiling methodology, corpus representativeness and linguistic comprehensiveness.

• Korean Journal of Computational Design and Engineering
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• v.16 no.4
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• pp.285-291
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• 2011

A pose estimation process from medical images is calculating locations and orientations of objects obtained from Computed Tomography (CT) volume data utilizing X-ray images from two directions. In this process, digitally reconstructed radiograph (DRR) images of spatially transformed objects are generated and compared to X-ray images repeatedly until reasonable transformation matrices of the objects are found. The DRR generation and image comparison take majority of the total time for this pose estimation. In this paper, a fast DRR generation technique based on GPU parallel computing is introduced. A volume ray-casting algorithm is explained with brief vector operations and a parallelization technique of the algorithm using Compute Unified Device Architecture (CUDA) is discussed. This paper also presents the implementation results and time measurements comparing to those from pure-CPU implementation and open source toolkit.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.9
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• pp.126-136
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• 1995

Copper magnetron anode of a microsave-over consists of an cylindrical outer-tube and various inner-vanes. The magnetron anode is produced by the complex processes; vane blanking, pipe cutting and silver-alloy brazing of vanes. Recently, the backward extrusion process for forming vanes has been developed to avoid the complex procedures. The developed process is analyzed by using upper-bound elemental technique (UBET). In the UBET analysis, the upper-bound load, the configuration and the vane-height of final extruded product are determined by minimizing the roral power consumption with repect to chosen parameters. To verify theoretical analysis, experiments have been carried out with pure plasticine billets at room temperature, using different web-thickness and number of vanes. The theoretical predictions both for forming load and vane-height are in reasonable agreement with the experimental results.