• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.666-670
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• 2013

Recovery method of silicon wafer from defective products generated from manufacturing process of silicon solar cells was studied. The removal effect of the N layer and antireflection coating (ARC) of the waste solar cell were investigated at room temperature ($25^{\circ}C$) by variation of concentration of $H_3PO_4$, $NH_4HF_2$, and concentration and types of chelating agent. Removal efficiency was the best in the conditions; 10 wt% $H_3PO_4$ 2.0 wt% $NH_4HF_2$, 1.5 wt% Hydantoin. Increasing the concentration of $H_3PO_4$, the surface contamination degree was increased and the thickness of the silicon wafe became thicker than the thickness before surface treatment because of re-adsorption on the silicon wafer surface by electrostatic attraction of the fine particles changed to (+). The etching method by mixed solution of $H_3PO_4$-$NH_4HF_2$-chelating agents was expected to be great as an alternative to conventional RCA cleaning methods and as the recycle method of waste solar cells, because all processes are performed at room temperature, the process is simple, and less wastewater, the removal efficiency of the surface of the solar cell was excellent.

• The Korean Journal of Nuclear Medicine
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• v.23 no.2
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• pp.219-223
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• 1989

Inflammation scan using radiolabelled leukocytes has high sensitivity and specificity. Several methods for labelling leukocytes have been evaluated using P-32 diisopropyl fluorophosphate (DFP-32), H-3 thymidine, Cr-51 chromate, Ga-67 citrate and Tc-99m-sulfur colloid. In-111-oxine has proved so far to be the most reliable agent for labelling leukocytes. In-111-oxine is, however, expensive, not easily available when needed, and its radiation dose to leukocytes is relatively high. Moreover, resolution of the resultant image is relatively poor. Tc-99m is still the agent of choice because of, as compared with the indium, its favorable physical characteristics, lower cost and availability. Now the technique for labelling the leukocytes with technetium is successfully obtained using the lipophilic HAPAO with higher efficiency for granulocytes than for other cells. With this technique it is possible to label leukocytes in plasma to improve the viability of the leukocytes. Inflammation scan using Tc-99m-HMPAO has been evaluated in several laboratories, and difference in methods for separation and labelling accounts for difference in efficiency, viability and biodistribution of the labelled leukocytes. We performed inflammation scan using leukocytes labelled with Tc-99m-HMPAO in three dogs 24 hours after inoculation of live E. Coli and A. Aureus in their right abdominal wall. We separated mixed leukocytes by simple sedimentation using 6% hetastarch (HES) and labelled the leukocytes with Tc-99m-HMPAO in 20% cell free plama diluted with phosphate buffer solution(Fig. 1). Uptake was high in the liver and spleen but is was minimal in the lungs on whole body scan. Kidneys and intestine showed minimal activity although it was high in the urinary bladder(Fig. 2). Uptake of labelled leukocytes in the inflammation site was do(mite on 2 hour-postinjection scan and abscess was clearly delineated on 24 hour-delayed scan with high target-to-nontarget ratio(Fig. 3, 4). Inflammation scan using mixed leukocytes labelled with Tc-99m-HMPAO is very sensitive and specific in early detection of inflammation.

• Korean Chemical Engineering Research
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• v.45 no.6
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• pp.619-626
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• 2007

It is of special interest in our membrane separation technology due to its low energy consumption and cost, relatively simple equipment, low investment and operation cost, et al. Full scale utilization of such processes can be widely utilized to the various fields. Using the difference of permeability of gas molecules between the filter layers, it is able to separate effectually pure gases from the mixed gases. In this paper, the membranes of PDMS, ${\gamma}-radiated$ PDMS, PTFE, PTFE-X are chosen to develop the predictive model for the separation of pure gases such as oxygen, nitrogen, hydrogen, and other gases from mixed gases. By utilizing the thermodynamic gas properties($\sigma$, $\varepsilon/k$) and experimental data of gas transport characteristics for different polymer membranes, it is able to develop the predictive model equation under the influence of temperature, pressure and polymer characteristics. Predictive model developed in this research showed good agreement with experimental data of gas permeability characteristics for develop four different polymer membranes. The proposed model can also be extended to the general equation for predicting the separation of gases based on the properties of polymeric membranes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.1
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• pp.21-31
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• 2002

This study applied each Neural Networks theory and Fuzzy Set theory to improve accuracy in remotely sensed images. Remotely sensed data have been used to map land cover. The accuracy is dependent on a range of factors related to the data set and methods used. Thus, the accuracy of maps derived from conventional supervised image classification techniques is a function of factors related to the training, allocation, and testing stages of the classification. Conventional image classification techniques assume that all the pixels within the image are pure. That is, that they represent an area of homogeneous cover of a single land-cover class. But, this assumption is often untenable with pixels of mixed land-cover composition abundant in an image. Mixed pixels are a major problem in land-cover mapping applications. For each pixel, the strengths of class membership derived in the classification may be related to its land-cover composition. Fuzzy classification techniques are the concept of a pixel having a degree of membership to all classes is fundamental to fuzzy-sets-based techniques. A major problem with the fuzzy-sets and probabilistic methods is that they are slow and computational demanding. For analyzing large data sets and rapid processing, alterative techniques are required. One particularly attractive approach is the use of artificial neural networks. These are non-parametric techniques which have been shown to generally be capable of classifying data as or more accurately than conventional classifiers. An artificial neural networks, once trained, may classify data extremely rapidly as the classification process may be reduced to the solution of a large number of extremely simple calculations which may be performed in parallel.

• The Korean Journal of Nuclear Medicine
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• v.24 no.1
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• pp.37-48
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• 1990

Detection of deep-seated abscesses is sometimes difficult with ultrasonogrpahy or computed tome graphy alone. Indium-111-labeled leukocyte has widely used in the localization of abscesses after introduction by Segal and Thakur in 1976. But there are some difficulties in using indium-111-oxine in our country because of hardness to get the radiopharmaceutical timely and long time for labeling leukocytes. So we peformed the indium-111-labeled leukocyte scan for establishment of the labeling procedure and clinical application. We labeled the mixed leukocytes from 36 ml of patient's blood using 4 ml of ACD solution, 7 ml of 6% hydroxyethyl starch solution $(HESPAN^{(R)})$, 1 mCi of indium-111 oxine, 5 ml of normal saline and centrifuge. It took about 2 hours for the preparation of radiolabeled leukocytes and attention for contamination was needed. The average injected dose of labeled mixed leukocytes was 465 uCi. The average number of injected leukocytes was $2.5\times10^8$ and the labeling ratio was $57{\pm}13%$ (Table 2, Fig. 5). These number and ratio were sufficient for the localization of abscess. About twenty per cent of indium was labeled to red blood cells and platelets (Fig. 6) and the half-life of injected radiolabeled leukocytes was 8.3 hours. Scan was performed in 9 patients who were suspected to have abscesses clinically or radiologically. Three patients were positive, in one patient who had abscess close to lower lumbar vertebrae was surgically drained and another 2 positive cases did not show abscess clearly on computed tomography, so only antibiotics were administrated and treated successfully. The negative 6 patients were improved without specific treatment. In conclusion, the use of indium-111 oxine labeled leukocytes for localization of abscesses were very specific and helpful in the decision of treatment considering its relatively simple labeling method, and could be easily performed providing timely supply of the radiopharmaceutical.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.65-85
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• 2023

The use of TBM (Tunnel boring machine) has increased worldwide due to its performance together with the benefit of being safely and environmentally friendly compared to conventional tunneling. In particular, EPB (Earth Pressure Balanced) TBM is widely used because it can be applied to various grounds compared to Open TBM. Also EPB TBM has a simple mechanical structure and advantages in cost, requires less ground area than Slurry TBM. EPB TBM has advantages in soft ground, and more importantly, can extend its applicability by use of appropriate soil conditioning, which improves mechanical and hydrological properties of excavated soil and increases the excavation performance of EPB TBM. Various studies suggested the proper mixing ratio and injection ratio, but almost they are limited to laboratory test under atmospheric pressure such as slump test. Actual field conditions may differ depending on the ground and mechanical condition. In this study, first the amount of used soil conditioning used in the field with various grounds from hard rock to soft ground was estimated through laboratory tests and compared with the estimate in design stage. And also it was compared with the amount used during actual excavation. In addition, experience of soil conditioning for the problems of cutter head clogging and groundwater inrush that occurred during excavation is discussed. Finally, lesson learned for the use of soil conditioning in difficult ground condition such as mixed ground are reviewed.

• Journal of the Korea Computer Graphics Society
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• v.30 no.1
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• pp.1-10
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• 2024

In immersive virtual environments including mixed reality (MR) and virtual reality (VR), avatars or agents, which are virtual humans, are being studied and applied in various ways as factors that increase users' social presence. Recently, studies are being conducted to apply generative AI as an agent to improve user learning effects or suggest a collaborative environment in an immersive virtual environment. This study proposes a novel method for interface application of a virtual assistant agent (VAA) using OpenAI's ChatGPT in an immersive virtual environment including VR and MR. The proposed method consists of an information agent that responds to user queries and a control agent that controls virtual objects and environments according to user needs. We set up a development environment that integrates the Unity 3D engine, OpenAI, and packages and development tools for user participation in MR and VR. Additionally, we set up a workflow that leads from voice input to the creation of a question query to an answer query, or a control request query to a control script. Based on this, MR and VR experience environments were produced, and experiments to confirm the performance of VAA were divided into response time of information agent and accuracy of control agent. It was confirmed that the interface application of the proposed VAA can increase efficiency in simple and repetitive tasks along with user-friendly features. We present a novel direction for the interface application of an immersive virtual environment through the proposed VAA and clarify the discovered problems and limitations so far.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.3
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• pp.181-194
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• 2017

This study aims to develop a regression model for forest volume estimation using field-collected forest inventory information and airborne LiDAR data. The response variable of the model is forest stem volume, was measured by random sampling from each individual plot of the 30 circular sample plots collected in Bonghwa-gun, Gyeong sangbuk-do, while the predictor variables for the model are Height Percentiles(HP) and Height Bin(HB), which are metrics extracted from raw LiDAR data. In order to find the most appropriate model, the candidate models are constructed from simple linear regression, quadratic polynomial regression and multiple regression analysis and the cross-validation tests were conducted for verification purposes. As a result, $R^2$ of the multiple regression models of $HB_{5-10}$, $HB_{15-20}$, $HB_{20-25}$, and $HBgt_{25}$ among the estimated models was the highest at 0.509, and the PRESS statistic of the simple linear regression model of $HP_{25}$ was the lowest at 122.352. $HB_{5-10}$, $HB_{15-20}$, $HB_{20-25}$, and $HBgt_{25}-based$ models, thus, are comparatively considered more appropriate for Korean forests with complicated vertical structures.

• Journal of the Korean Society of Costume
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• v.53 no.2
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• pp.153-169
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• 2003

I think that apparel attaches importance to the degree of satisfaction of visual expression in one ornamental culture in which it is clothed on human body. whereas a tattoo attaches more importance to part of the expression of one's own identity in the same context. However. modern tattooing act was highlighted only as an element of act which was negative in the purpose and the degree of taste or which assumed the grotesque meaning of a particular group. away from pure concepts such as simple ornament or an amulet according to the flow of the world. A tattoo is gradually being seen as one of avant-garde methods of art again these days, and TATTOO LOOK is being popularized as street fashion as an effective method of one's own satisfied desires and peculiar expression of personality. I have got the following conclusions as the result of having studied on a tattoo which is establishing itself as another plastic art that is matchable with the fashion of dress and its ornaments in which human incessant instinctive desire for the ornament of body has been beyond nostalgia for the past and simple ornament which were pure in up-to-date modern society First, a tattoo is of personality. In that it solidifies one's own personality of another side by being transformed, one's own attraction can be transferred to a fashion tattoo with which one can emit one's own personality. Secondly. a tattoo is fashion. As a new body ornament called transformation by a tattoo was emerging, the fashionableness owned by a tattoo had in its area ample room for the fashionableness with which it can coexist with the culture of dress and its ornaments. Thirdly. a tattoo is popularized. TATTOO LOOK in which one's own satisfied desires and the expression of personality are properly applied is being recently transmitted easily everywhere in the world and popularized as street fashion. Fourthly, a tattoo is not depraved art. It's because of the point that a tattoo which had been recognized only as a decadent expression in which avant-garde elements of unknown nationality appeared mixed showed the possibility that it could establish itself as fashion art. If we go on studying and complementing the problems of individual sides about a tattoo also in the future, the infinite fashionableness for the elements called personality. sense and emotion owned by a tattoo suggested ample possibility as future industry to be highlighted.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.129-133
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• 1999

For the myopia eyes of the people which are ametropia, the classified distribution has showed % for the simple myopic, 50% for the compound myopic astigmatism, 15% for the simple myopic astigmatism and 19% for the mixed astigmatism. The myopic ametropia for the both eyes has the distribution of 35% for -0.50D~-2.00Dptr, 54% for -2.00~6.00Dptr, and 11% for over -6.00Dptr. The classifying distribution for the age for the myopic ametropia was 54% for 15~20, 22% for 21~40, 14% for 41~60 and 10% for 61. The occupational distribution for the myopic ametropia has showed 61.5% for the student(Middle, High, College), 13.5% for the office worker, and 15% for the house wives as well as the small business. The hour affecting the refraction most for a day was after P.M. 7 which recorded 45% as the highest value. The reason is that the myopia degree decreases in the morning as the cornea flats and the situation is reversed in the afternoon so that there is a difference of Sph -0.50D and as getting darker the refraction degree of the light coming through the enlarged pupil refraction around the cornea is high. For the seasons the highest myopic degree has been recorded for 68% in the summer due to the shortage of nutrition and the climination inside the body by the exhaustion of sweat. In the blood types A and B are distributed closely as 34% and more active man with O has recorded higher myopic degree than woman. However woman showed higher accommodation power than man regardless the blood types. In the characteristic factors of myopic eye, the character feels fatigue easily has showed the distribution for 42% which is the highest and it could be classified largely by two the.