• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.791-803
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• 2007

The purpose of this study was to evaluate exophytically vertical bone formation in residual ridge of the beagle dog by the concept of guided bone regeneration with a titanium reinforced e-PTFE membrane combined with irradiated cancellous human bone. Twelve male beagle dogs(mean age 1.5 years and mean weight 12kg) were used for this study. The alveolar ridges after extraction of all mandibular premolars were surgically and horizontally removed. At 8 weeks after extractions, full-thickness flap was reflected and cortical bone was removed with round bur and copious irrigation. Rectangular parallelepiped(10mm in length, 5mm in width, and 4mm in height) bended with titanium-reinforced e-PTFE(TR e-PTFE) membrane was placed on the decorticated alveolar ridge, fixed with metal pins and covered with full-thickness flap and assigned as a control group. Test groups ere treated with TR e-PTFE membrane filled with irradiated cancellous human bone. Of twelve beagle dogs, four control dogs and four test dogs without membrane exposure to oral cavity were sacrificed at 8 and 16 weeks respectively. The surgical sites were dissected out, fixed in 4% buffered formaldehyde, dyed using a Villanueva staining technique, and processed for embedding in plastic resin. The cutting and grinding methods were routinely processed for histologic and histomophometric analyis of exophytic bone formation as well as statistical analysis. The results of this study were as follows: 1. Exophytic bone formation in the both of experimental groups was increased respectively after surgery from 23.40% at 8 weeks to 46.26% at 16 weeks in the control groups, from 40.23% at 8 weeks to 47.11% at 16 weeks in the test groups(p<0.05). 2. At 8 weeks after surgery, exophytic bone formation was made 40.23% in the test groups and 33.40% in the control groups. Exophytic bone formation was significantly made in the test group more than in the control group. At 16 weeks after surgery, exophytic bone formation was made 44.11% in the test groups and 46.26% in the control groups. Exophytic bone formation was made in the test groups more than in the control groups, but there was no statistically significant differences. 3. The membrane was fixed with metal pins to closely contact it to the bone surface. So, collapse and deviation of the membrane could be prevented and in growth of connective tissue also could be blocked from the periphery of the membrane. On the basis of these findings, wee suggest that intraoral experimental model for exophytic bone formation may be effective to evaluate the effect of bone graft material. And it indicates that combined use of membrane and ICB graft material is more effective than use of membrane only for exophytic bone formation.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.07a
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• pp.25-37
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• 2002

The most important industrial application of gamma radiation in characterizing green compacts is the determination of the density. Examples are given where this method is applied in manufacturing technical components in powder metallurgy. The requirements imposed by modern quality management systems and operation by the workforce in industrial production are described. The accuracy of measurement achieved with this method is demonstrated and a comparison is given with other test methods to measure the density. The advantages and limitations of gamma ray densitometry are outlined. The gamma ray densitometer measures the attenuation of gamma radiation penetrating the test parts (Fig. 1). As the capability of compacts to absorb this type of radiation depends on their density, the attenuation of gamma radiation can serve as a measure of the density. The volume of the part being tested is defined by the size of the aperture screeniing out the radiation. It is a channel with the cross section of the aperture whose length is the height of the test part. The intensity of the radiation identified by the detector is the quantity used to determine the material density. Gamma ray densitometry can equally be performed on green compacts as well as on sintered components. Neither special preparation of test parts nor skilled personnel is required to perform the measurement; neither liquids nor other harmful substances are involved. When parts are exhibiting local density variations, which is normally the case in powder compaction, sectional densities can be determined in different parts of the sample without cutting it into pieces. The test is non-destructive, i.e. the parts can still be used after the measurement and do not have to be scrapped. The measurement is controlled by a special PC based software. All results are available for further processing by in-house quality documentation and supervision of measurements. Tool setting for multi-level components can be much improved by using this test method. When a densitometer is installed on the press shop floor, it can be operated by the tool setter himself. Then he can return to the press and immediately implement the corrections. Transfer of sample parts to the lab for density testing can be eliminated and results for the correction of tool settings are more readily available. This helps to reduce the time required for tool setting and clearly improves the productivity of powder presses. The range of materials where this method can be successfully applied covers almost the entire periodic system of the elements. It reaches from the light elements such as graphite via light metals (AI, Mg, Li, Ti) and their alloys, ceramics ($AI_20_3$, SiC, Si_3N_4, $Zr0_2$, ...), magnetic materials (hard and soft ferrites, AlNiCo, Nd-Fe-B, ...), metals including iron and alloy steels, Cu, Ni and Co based alloys to refractory and heavy metals (W, Mo, ...) as well as hardmetals. The gamma radiation required for the measurement is generated by radioactive sources which are produced by nuclear technology. These nuclear materials are safely encapsulated in stainless steel capsules so that no radioactive material can escape from the protective shielding container. The gamma ray densitometer is subject to the strict regulations for the use of radioactive materials. The radiation shield is so effective that there is no elevation of the natural radiation level outside the instrument. Personal dosimetry by the operating personnel is not required. Even in case of malfunction, loss of power and incorrect operation, the escape of gamma radiation from the instrument is positively prevented.

• Journal of Korea Foundry Society
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• v.20 no.5
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• pp.330-335
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• 2000

Functional metal prototypes are often required in numerous industrial applications. These components are typically needed in the early stage of a project to determine form, fit and function. Recent R/P(Rapid Prototyping) part are made of soft materials such as plastics, wax, paper, these master models cannot be employed durable test in real harsh working environment. Parts by direct metal rapid tooling method, such as laser sintering, by now are hard to get net shape, pores of the green parts of powder casting method must be infiltrated to get proper strength as tool, and new type of 3D direct tooling system combining fabrication welding arc and cutting process is reported. But a system which can build directly 3D parts of high performance functional material as metal park would get long period of system development, massive investment and other serious obstacles, such as patent. In this paper, through the rapid tooling process as silicon rubber molding using R/P master model, and fabricate wax pattern in that silicon rubber mold using vacuum casting method, then we translated the wax patterns to numerous metal tool prototypes by new investment casting process combined conventional investment casting with rapid prototyping & rapid tooling process. With this wax-injection-mold-free investment casting, we developed new investment casting process of fabricating numerous functional metal prototypes from one master model, combined 3-D CAD, R/P and conventional investment casting and tried to expect net shape measuring total dimension shrinkage from R/P pare to metal part.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.85-94
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• 1999

Reinforced Soil Wall has several merits comparing with conventional retaining wall. The conventional method has the limit of wall height, ununiform settlement of the foundation ground, quality assurance of the embankment body, shortening of construction period, economical construction and so on. Basis of previous mentioned things reinforced soil wall is the substitutional method of conventional retaining wall and its necessity is continuously increasing. The embanking material used in reinforced soil wall is generally limited such as a good quality sandy soil, and in many case constructors have to transfer such a good embanking material from far away to construction site. As a result, they would pressed by time and economy. If poor soils could be used embanking material, for example, clayey soil produced in-situ by cutting and excavation, the economical merit of reinforced soil wall would be increased more and more. Likewise, a lot of study about laboratory experimental behavior of reinforced soil wall using a good quality soil is being performed, but is rare study about clayey soil containing much volume of fine particle relatively in korea. In this study, the authors investigated behavior of the geosynthetic reinforced and unreinforced soil walls using clayey soil as embanking material in view of horizontal movement of walls, bearing capacity and reinforcement stress.

• Journal of the Korean Graphic Arts Communication Society
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• v.30 no.1
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• pp.21-33
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• 2012

This research attempts to analyze the effect of printed-saving coupons distributed by major discount store on consumer purchasing intention. Those consumers having used printed-saving coupon in major discount store in Daejeon were selected as respondents. 121 copies were retreated from 150 questionnaires. For data analysis, frequency analysis for respondents' characteristics, Cronbach's alpha for reliability of analysis, and $X^2$ test of multi-regression analysis for testing hypothesis were utilized. The result of analysis shows 1) the way of using coupon is respectively different according to sex, age group, marital status, term of coupon, and the number of using coupon; 2) Attributes of coupon partially influence on purchasing intention of consumers. Only shopping cost cutting is insignificant, while keeping convenience, impulse buying, scheduled purchasing are significant. The most effective variable is scheduled purchasing, keeping convenience, and impulse buying influence on purchasing intension of consumers. Therefore, offering printed-coupon by major discount store is useful tool to induce consumers to planned purchasing.

• Journal of Welding and Joining
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• v.30 no.6
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• pp.74-79
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• 2012

It depends on the joint configuration, dimensions and constraints of the joint whether the residual stress at the root of single-sided butt weld is tensile or not. Therefore, recommendation is generally made that high R ratio should be used in the fatigue test of welded joint in order to prevent excessively long life caused by compressive residual stress. In this research, the residual stress profile in butt weld joint was obtained through compliance method, using successive extension of a slot and measurement of the variation of strain during the slot extension. The residual stress profile was firstly assumed to be the linear summation of Legendre polynomials up to 9th order excluding 0th and 1st order. Strain variation on the surface was measured while the slot was being extended by cutting to find out the 8 unknown coefficients of each polynomial term. The cut was made by the electric discharge machine. It was concluded that the residual stress near the surface is positive valued, however, it turned into the negative value as soon as it passed through 2 or 3 mm of the depth.

• The Research Journal of the Costume Culture
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• v.19 no.2
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• pp.324-333
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• 2011

This study was accomplished for the purpose of developing a textile processing ingredient that is harmless to the human body and environment. The research method consists of dyeing cotton textiles by extracting the dye solution from ginseng. Then, chrominance, after treatment, antibacterial ratio and deodorization ratio of cotton fabrics dyed with ginseng extracts were tested and results were examined. The research procedure involved first extracting the dye solution from the ginseng's by-product (fine roots) and then dyeing was effectuated differently according to the test samples temperature and dyeing time requirements. Brightness in all dye substances was lower in pre-mordanting. Beige color could be extracted from pre-mordanted samples. And dark orange from postmordanted samples. Color-festness was high in all samples. Most of samples show a big antibacterial ratio and deodorization ratio. Through this research it has been discovered that, when applied to textiles, Korea's ginseng extract possessed reproducibility features as a natural dye and a possibility to be used in cutting which plays a crucial role in hygienic processing. In addition, by using ginseng's by-product for dyeing processing as the dye solution, efficient application of resources and occurrences of no water waste damages were demonstrated and thus, proved to be environmentally-friendly. Specifically, through this experiment, it was found that saponin, ginseng's special characteristics, possessed excellent antibacterial odor repelling functions to clothing as well as the capability to prevent skin disease.

• Geomechanics and Engineering
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• v.12 no.5
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• pp.785-801
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• 2017

Biopolymer treatment of geomaterials to develop sustainable geotechnical systems is an important step towards the reduction of global warming. The cutting edge technology of biopolymer treatment is not only environment friendly but also has widespread application. This paper presents the strength and slake durability characteristics of biopolymer-treated sand sampled from Al-Sharqia Desert in Oman. The specimens were prepared by mixing sand at various proportions by weight of xanthan gum biopolymer. To make a comparison with conventional methods of ground improvement, cement treated sand specimens were also prepared. To demonstrate the effects of wetting and drying, standard slake durability tests were also conducted on the specimens. According to the results of strength tests, xanthan gum treatment increased the unconfined strength of sand, similar to the strengthening effect of mixing cement in sand. The slake durability test results indicated that the resistance of biopolymer-treated sand to disintegration upon interaction with water is stronger than that of cement treated sand. The percentage of xanthan gum to treat sand is proposed as 2-3% for optimal performance in terms of strength and durability. SEM analysis of biopolymer-treated sand specimens also confirms that the sand particles are linked through the biopolymer, which has increased shear resistance and durability. Results of this study imply xanthan gum biopolymer treatment as an eco-friendly technique to improve the mechanical properties of desert sand. However, the strengthening effect due to the biopolymer treatment of sand can be weakened upon interaction with water.

• Korean Journal of Agricultural Science
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• v.30 no.2
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• pp.139-147
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• 2003

The main purpose of this study is to obtain forest scenic beauty management informations toward forest working systems in pinus densiflora forest stands, etc. To get these information, visual preference and spatial image analysis methods are used. 25 different alternatives were simulated to visualize on basis of actual forest working methods with taken photos from May to July, 2003. The options were illustrated as photos produced by computer software. Respondents' ratings for 25 landscape scenes were obtained by interview survey method. Each alternatives were evaluated by forest major student group with total 103 respondents after reliability test. Visual preference evaluation was used 10 point rating scale. Spatial images of 12 alternatives were measured by 12 semantic differential scale. In general, the respondents preferred refreshing and ordering forest stand after forest working to natural forest stand before forest working. High visual preference for forest density produces 400-600 trees/ha in small diameter class forest stands. Regarding visual preference according to pavement type of trail, soil trail is ranked high. Visual preference for cutting area ranks mature forest stand and visual preference for trail slope cover type ranks shrub with grass as relatively high on the preference scale. Through the factor analysis, spatial images of 12 coniferous forest stands are classified as 'ordered opened' and 'beautiful healthy'. Results indicate how to conduct forest working systems for forest scenic beauty management.

• Journal of the Korea Convergence Society
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• v.7 no.1
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• pp.17-23
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• 2016

In this paper, we describe a case of utilizing SaaS technology to build NC Post-processor(WBS) based cloud computing. Developed WPS system was implemented to provide stable and continuous system service by utilizing SCoD methodology. WPS is designed user interface module and control engine module. The interface module is downloaded in a client PC and the control engine is installed in cloud parm area. These modules are connected with computer network. WPS was completed a function test for sheet cutting field and mold manufacturing field, and it is processing a commercial service using with improve the user's convenience and adding a bill charge module.