• Magazine of the Korean Society of Agricultural Engineers
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• v.22 no.1
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• pp.53-66
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• 1980

The research work is concerned with the analytical and experimental studies on the heat transfer phenomenon around the underground concrete digester used for biogas production Systems. A mathematical and computational method was developed to estimate heat losses from underground cylindrical concrete digester used for biogas production systems. To test its feasibility and to evaluate thermal parameters of materials related, the method was applied to six physical model digesters. The cylindrical concrete digester was taken as a physical model, to which the model,atical model of heat balance can be applied. The mathematical model was transformed by means of finite element method and used to analyze temperature distribution with respect to several boundary conditions and design parameters. The design parameters of experimental digesters were selected as; three different sizes 40cm by 80cm, 80cm by 160cm and l00cm by 200cm in diameter and height; two different levels of insulation materials-plain concrete and vermiculite mixing in concrete; and two different types of installation-underground and half-exposed. In order to carry out a particular aim of this study, the liquid within the digester was substituted by water, and its temperature was controlled in five levels-35。 C, 30。 C, 25。 C, 20。C and 15。C; and the ambient air temperature and ground temperature were checked out of the system under natural winter climate conditions. The following results were drawn from the study. 1.The analytical method, by which the estimated values of temperature distribution around a cylindrical digester were obtained, was able to be generally accepted from the comparison of the estimated values with the measured. However, the difference between the estimated and measured temperature had a trend to be considerably increased when the ambient temperature was relatively low. This was mainly related variations of input parameters including the thermal conductivity of soil, applied to the numerical analysis. Consequently, the improvement of these input data for the simulated operation of the numerical analysis is expected as an approach to obtain better refined estimation. 2.The difference between estimated and measured heat losses was shown to have the similar trend to that of temperature distribution discussed above. 3.It was found that a map of isothermal lines drawn from the estimated temperature distribution was very useful for a general observation of the direction and rate of heat transfer within the boundary. From this analysis, it was interpreted that most of heat losses is passed through the triangular section bounded within 45 degrees toward the wall at the bottom edge of the digesten Therefore, any effective insulation should be considered within this region. 4.It was verified by experiment that heat loss per unit volume of liquid was reduced as the size of the digester became larger For instance, at the liquid temperature of 35˚ C, the heat loss per unit volume from the 0. 1m$^3$ digester was 1, 050 Kcal/hr m$^3$, while at for 1. 57m$^3$ digester was 150 Kcal/hr m$^3$. 5.In the light of insulation, the vermiculite concrete was consistently shown to be superior to the plain concrete. At the liquid temperature ranging from 15。 C to 350 C, the reduction of heat loss was ranged from 5% to 25% for the half-exposed digester, while from 10% to 28% for the fully underground digester. 6.In the comparison of heat loss between the half-exposed and underground digesters, the heat loss from the former was fr6m 1,6 to 2, 6 times as much as that from the latter. This leads to the evidence that the underground digester takes advantage of heat conservation during winter.

• Cartoon and Animation Studies
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• s.50
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• pp.101-130
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• 2018

Since the advent of the Smart Devices, the smartphone has become a popular tool to view Webtoon. This phenomenon has caused the convergence of cutting-edge technologies and Webtoons in diverse forms, creating unique versions of Webtoons including, but not limited to Smart-toon, Effect-toon, Cut-toon, Dubbing-toon, Moving-toon, AR-toon, VR-toon, and Interaction-toon. By comparison to these rich diversities of Webtoons in the online industry, there is a lack of academic research on this topic. There are some papers which talk about the different types of multimedia technology conversion and its case presentation or the effectiveness and problems of visual effect, but the effects of these convergence technologies on comic readers' concentration and reading effectiveness have never been investigated so far. Therefore, this paper will discuss the unique method of immersive storytelling that is often used in comics and analyze each aspects of immersive method in technology-converged Webtoons along with its problems. Furthermore, this paper will analyze different aspects of "immersion" and interaction elements that can be found in the popular Interaction-toon, (Encountered). Through this, this paper discusses the positive influence of the interaction elements on comic readers' immersion level and its limitation. To classify the technology-converged Webtoons in terms of the immersion level, the Effect-toon sometimes interferes viewer's flow by using excessive use of multimedia effect, creating information overload. The Smart-toon which applied motions to each frame under horizontal mode of smartphones was a good try, but it hindered the readers' activeness and made it hard for the readers to be fully absorbed in the story. The VR-toon, which utilizes virtual reality gadgets to allow viewers to explore the world of Webtoon was also a nice try to overcome the limitation of vertical screens. However, it often caused dispersion of user's attention and reduced the users' immersion level. The Moving-toon which only emphasized the reading convenience also invaded readers' activeness and disturb users' concentration. On the other hand, the cartoonist Il-Kwon Ha applied high technologies such as face recognition technology, augmented reality techniques, 360-degree panorama technology, and haptic technology to his cartoon (Encountered). This allowed the readers to form a sense of closeness towards the cartoon characters which let the readers to identify themselves with the characters and interact with them. By this way, the readers can be fully immersed in the story. However, technology abuse, impractical production and hackneyed storylining often showed later in the story remains as its limitations.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.329-341
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• 1998

Sterilization has received much attention in orthodontic practices over the past several years. The present study was undertaken to investigate the effects of sterilization on the physical properties of orthodontic pliers-AEZ, Unitek, and Dentronix ligature cutters. This study was designed to examine the tips of ligature cutters before and after 200 and 400 sterilization cycles using the Bowmar RHT-1000, the Dentronix DDS-5000, and the Eschmann SES-2000. The tip surface and the fracture surface were observed with a scanning electron microscope. The microstructure was observed with an optical microscope. The hardness test was carried out with the mic개-Vickers hardness tester and the Rockwell C Scale hardness tester. The chemical composition was analyzed by energy dispersive X-ray spectrometer. The results of this study were as follows : 1. The number and the size of corrosion products on the tip surface and the proportion of cleavage planes in fractured specimen increased, but the hardness of the tip decreased in proportion to sterilization cycles. From these observations, it was considered that mechanical properities decreased in proportion to sterilization cycles. 2. The number and the size of chromium carbides increased in proportion to sterilization cycles. Coarse microstructure decreased mechanical properities. 3. The AEZ and Unitek ligature cutters were Fe-Cr stainless steels, but the Dentronix ligature cutter was Co-Cr alloy. There were many differences among manufactures, but the chemical composition was .not changed after sterilization cycles. 4. The tip edge of ligature cutter used in a clinic revealed microcracks with the SEM observation. Clinical experience confirmed that ligature cutters were gradually degraded by sterilization.

• Korean Journal of Construction Engineering and Management
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• v.16 no.1
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• pp.52-63
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• 2015

Business facilities among domestic architectures have rapidly been constructed along with domestic economic development. It is an important facility taking the second largest proportion next to apartment buildings among current 31 building types of fire department classification of 2012 year for urban architectures. The expected service life of business facilities is 15 years, but 70% of those in urban areas have surpassed the 15 year service life as of the present 2014. Thus, the demand for urgent rehabilitation of such facilities is constantly increasing due to the aging and performance deterioration of the facilities'main finishing materials. Especially, the business facilities are being used for the lease of company office or private office, and such problems as aging and performance deterioration of the facilities could cause less competitive edge for leasing and real estate value depreciation for the O&M (Operation & Management) agent and the owner, respectively. Therefore, an effective planned rehabilitation as a preventive measure according to the standardized repair rate by the number of years after the construction is in need in order to prevent the aging and performance deterioration of the facilities(La et al. 2001). Nonetheless, domestic repair/rehabilitation standards based on the repair rate are mainly limited to apartment buildings and pubic institutions, resulting in impractical application of such standards to business facilities. It has been investigated and analyzed that annual repair rate data for each finishing material are required for examination of the applicability of the repair rate standard for the purpose of establishment of a repair plan. Hence, this study aimed at developing a repair rate computation model for finishing materials of the facilities and verifying the appropriateness of the annual repair rate for each finishing material through a case study after collecting and analyzing the repair history data of six business facilities. The results of this study are expected to contribute to the planning and implementation of more efficient repair/rehabilitation budget by preventing the waste of unpredicted repair cost and opportunity cost for the sake of the business facilities' owners and O&M agents.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.3
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• pp.19-27
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• 2003

Surface finishes of PCB laminates are important in the solder joint reliability of flip chip package because the types and thicknesses of intermetallic compound(IMC), and compositions and hardness of solders are affected by them. In this study, effects of surface finishes of PCB on the low cycle fatigue resistance of Sn-based lead-free solders; Sn-3.5Ag, Sn-3.5Ag-XCu(X=0.75, 1.5), Sn-3.5Ag-XBi(X=2.5, 7.5) and Sn-0.7Cu were investigated for the Cu and Au/Ni surface finish treatments. Displacement controlled room temperature lap shear fatigue tests showed that fatigue resistance of Sn-3.5Ag-XCu(X=0.75, 1.5), Sn-3.5Ag and Sn-0.7Cu alloys were more or less the same each other but much better than that of Bi containing alloys regardless of the surface finish layer used. In general, solder joints on the Au/Ni finish showed better fatigue resistance than those on the Cu finish. Cross-sectional fractography revealed microcracks nucleation inside of the interfacial IMC near the solder mask edge, more frequently on the Cu than the Au/Ni surface finish. Macro cracks followed the solder/IMC interface in the Bi containing alloys, while they propagated in the solder matrix in other alloys. It was ascribed to the Bi segregation at the solder/IMC interface and the solid solution hardening effect of Bi in the $\beta-Sn$ matrix.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.173-179
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• 2009

Purpose: On the hypothesis that the acromion morphology is changed according to the its site, we identified the morphology of the acromion on the oblique slices of MRI and we investigated the association of the acromial shape with the clinical stages of rotator cuff disorder on the magnetic resonance (MR) images. In addition, we compared the acromion morphology on MRI and simple X-rays. Material and Methods: The MR images of seventy one patients with rotator cuff disorder and who underwent arthroscopic surgery were compared with that of a control group of sixteen patients who didn't have rotator cuff disorder on MRI. On three subsequent oblique sagittal slices from the lateral edge of the acromion (S1, S2 and S3), each acromion morphology on the MRI slices was classified according to Epstein et al: flat, curved or hooked. We investigated the changing parttern of the acromion shape and we compared the acromion shape on MRI and that on simple X-rays. We classified the rotator cuff tear by the severity: bursitis, partial thickness tear or full thickness tear. We investigated which acromial type on the MRI oblique slice was associated with the severity of rotator cuff disease. Results: Changes of the acromial shape occurred in 54 patients (76.1%). The most frequent pattern was that the types are same on S1 and S2 and different on S3 (22 cases, 31.0%). The acromial type on S1 and S2 was significantly associated with the severity of rotator cuff disorder (p=0.001 and 0.022), respectively. There was no reliability of the acromial shape on MRI and roentgenography (p>0.05) Conclusion: The type of acromion changed from lateral to medial. Among the three positions, the shape of the acromion on S1 and S2 had meaningful correlation with the clinical stage of rotator cuff disorder. There was no statistical correlation of the acromial shape between MRI and simple X-ray.

• Journal of Animal Environmental Science
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• v.16 no.3
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• pp.237-244
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• 2010

Using a vertical composting system in layer farms, the composting process was characterized in terms of temperature variation, change of moisture contents, fertilizer ingredient and so on. In this study, two types of layer farms were examined. The layer manure was produced as 3,300 and 116,650 kg/day for Farm A and Farm B, respectively. Also, their average moisture contents were 74.4% (Farm A) and 65.6 % (Farm B). The inside temperature of composting in Farm A was varied in the range of 50 to $70^{\circ}C$, and moisture content of it decreased from 59.5% to 20.6% at the edge of vertical composting system. While in Farm B, composting temperature was fluctuated between 50 and $65^{\circ}C$ and moisture content declined from 34.0% to 13.4% at the end of vertical composting system. The fertilizer ingredients such as T-N, $P_2O_5$ and $K_2O$ were not significantly influenced by seasonal effect. Their values were changed in the range of 0.90% to 0.47% for T-N, 0.16% to 0.42% for $P_2O_5$, and 0.22% to 0.28 for $K_2O$, respectively. Also, OM/N ratio was varied from 36.8 to 84.4.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.804-811
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• 2010

The lower portion of sloping paddy fields normally contains excessive moisture and the higher water table caused by the inflow of ground water from the upper part of the field resulting in non-uniform water content distribution. Four drainage methods namely Open Ditch, Vinyl Barrier, Pipe Drainage and Tube Bundle for multiple land use were installed within 1-m position from the lower edge of the upper embankment of sloping alluvial paddy fields. Knowledge of the spatial variability of soil water properties is of primary importance for management of agricultural lands. This study was conducted to evaluate the effect of drainage in the soil on spatial variability of soil water content using the geostatistical analysis. The soil water content was collected by a TDR (Time Domain Reflectometry) sensor after the installation of subsurface drainage on regular square grid of 80 m at 20 m paddy field located at Oesan-ri, Buk-myeon, Changwon-si in alluvial slopping paddy fields ($35^{\circ}22^{\prime}$ N, $128^{\circ}35^{\prime}$). In order to obtain the most accurate field information, the sampling grid was divided 3 m by 3 m unit mesh by four drainage types. The results showed that spatial variance of soil water content by subsurface drainage was reduced, though yield of soybean showed the same trends. Value of "sill" of soil water content with semivariogram was 9.7 in Pipe Drainage, 86.2 in Open Ditch, and 66.8 in Vinyl Barrier and 15.7 in Tube Bundle.

• Korean Journal of Heritage: History & Science
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• v.51 no.4
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• pp.84-107
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• 2018

Cheommojik is a pile cloth, a type of textile whose surface is covered with short piles. The term chaedam was used during the late Joseon dynasty to refer to pile cloth rugs, while the terms yoongjeon, dantong and yangtanja were used in the early twentieth century. Various documents, newspaper articles and photographs confirm that pile cloth rugs were used by the general public as well as the royal family from the late Joseon dynasty onward, and that there were domestic manufacturers of such rugs at that time. This study investigated six pile cloth rugs that were produced after the late Joseon dynasty, five of which feature Persian knots made of cut pile, the other being made with the loop pile method. The cut pile rugs are rectangular in shape and measure between 72-98cm by 150-156cm; and they are decorated in the middle with patterns of butterfly, deer, and tiger or the ten longevity symbols, and along the edges with patterns composed of 卍 symbols. The ground warp of all six rugs are made from cotton yarn, while the ground weft is made of cotton yarn on three pieces, wool on one piece and cotton and viscose rayon. The ground weft yarn from four pieces are Z-twist yarn made with two or more S-twist cotton yarn. Four to six colors were used for the pile weft, all being natural colors except for red. Two or more S- or Z-twist yarn were twisted together in the opposite twist for the pile weft, with the thickness determining the number of threads used. Six or more weft threads were used to make the start and end points of the rug; and the ground warp ends were arranged by tying every four of them together. For the left and right edges, three or more threads were wrapped together into a round stick-like form, and the second and third inner ground warps from the edges were stitched on to the wrapped edge. For the loop pile, loops were made in the direction of the warp; the ground warp and the ground weft may have been made with cotton, the pile warp with wool yarn. An analysis of the components of three rugs was conducted to determine which types of animal hair were used for the pile weft. Despite some inconclusive results, it was revealed that goat hair and fat-tailed sheep hair were used, raising the possibility that various kinds of animal fur were used in the production of pile cloth rugs. The six rugs examined in this study are estimated to have been made between the late 1800s and the early 1900s. Although the manufacturer of the rugs cannot be confirmed, we concluded that the rugs were produced in Korea after referring to the documentation of the domestic production of pile cloth rugs during the aforementioned period and the form and placements of the patterns on the rugs.

• Korean Journal of Heritage: History & Science
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• v.52 no.1
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• pp.4-21
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• 2019

In this paper, 23 Silla gold earrings from the sixth and seventhand centuries, excavated from the Yeongnam region, were analyzed. Based on the silver content of the gold plate, they were classified into three types. The classifications included type I(20-50wt%), type II(10-20wt%) and type III (less than 10wt%). In the analysis process, the composition and morphological differences were identified on the surface of the gold plate. In the case of type I and II earrings, it was observed that the fine holes were concentrated in a relatively higher part of the gold content. The causes of the difference in the surface composition of the gold plate were divided into four categories: 1) surface treatment, 2) thermal diffusivity in the manufacturing process, 3) differences in composition of alluvial gold, and 4) the refining method of gold. It is possible that depletion gilding was attempted to increase the gold content while intentionally removing the other metals from the surface of the gold alloy in the portion where the gold deposit is relatively concentrated on the surface of the gold plating. The highest copper content was detected in the earring with the highest gold content of the analyzed earrings, and it was assumed that thermal diffusion had occurred between the gold plate and the metal rod during the manufacturing process rather than intentional addition. Copper was detected only in the thin ring earring type, and copper was not detected in the thick ring earring type or pendant type. It also proves that this earring has a high degree of tightness at higher temperatures, as there was an invisible edge finish on other earrings and horizontal wrinkles on the gold plate surface. In terms of the material of the gold plate, we examined whether the silver content of the gold plate was natural gold or added by alloy through analyzing the alluvial gold collected in the region. As a result of the analysis, it was found that on average about 13wt% of silver is included. This suggests that type II is natural gold, type III is refined gold, and type I seems to have been alloyed with natural gold. Here, we investigated the refining method introduced in the ancient literature, both at home and abroad, about the possibility of alloying silver after the refining process of type III earrings and then making pure gold. It was found that from ancient refining methods, silver which had been present in the natural gold was removed by reacting and combining with silver chloride or silver sulfide, and long-term efforts and techniques were required to obtain pure gold through this method. Therefore, it was concluded that the possibility of adding a small amount of silver in order to increase strength after making pure gold through a refining process is low.