• The korean journal of orthodontics
• /
• v.48 no.2
• /
• pp.107-112
• /
• 2018

Objective: The aim of this study was to examine the properties of fiber-reinforced composite and stainless steel twisted retainers for orthodontic retention. Methods: Three different span lengths (5.0, 8.0, and 14.0 mm) of fiber-reinforced composite were investigated. The three fiber-reinforced composite retainer groups were subdivided according to the storage condition (dry and wet), resulting in a total of six groups. Each stainless steel and fiber-reinforced composite group was comprised of six specimens. The three-point bending flexural test was conducted using a universal testing machine. ANOVA was used to assess differences in the maximum load and maximum stress according to the span length, material, and storage condition. Post-hoc comparisons were performed if necessary. Results: The maximum stress and maximum load were significantly (p < 0.001) associated with the span length, material, and storage condition. The significant interaction between the material and span length (p < 0.001) indicated the differential effects of the material for each span length on the maximum stress and maximum load, with the difference between materials being the highest for the maximum span length. Conclusions: Our findings suggest that fiber-reinforced composite retainers may be an effective alternative for orthodontic retention in patients with esthetic concerns or allergy to conventional stainless steel wires.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2003.10a
• /
• pp.986-989
• /
• 2003

In the steel production line, the molten metal of a furnace is transformed into slab material and then move to the hot strip line, This paper describe about the real time recognition system of material management number, which is marked at the surface of a slab in the steel production line. This recognition processing should be performed before the slab is moved to the hot strip line. This system include following recognition steps. First, we remove noise from the captured slab image by use pre-filter. Second, we extract rough area, which is include slab number and then, we extract individual number area. Finally, we recognize material management number by use KLT(Karhunen-Loeve transform) algorithm. We applied our system to the real slave image, which was captured in the process line. In the results, we recognized slave number to the 94% accuracy.

• Korean Institute of Interior Design Journal
• /
• v.22 no.5
• /
• pp.216-224
• /
• 2013

There are the relevant provisions that apply to building regulations about the Building codes, Fire Protection laws, and more Multi-using interior finish materials businesses etc. The differences between these regulations are as follows: The Building codes is defined the main use of the building according to facilities to used to set the scale by the use of the floor space, On the other hand, Fire Protection laws are the basic purpose and the act of using the architectural space(or sales) by separating object by fire. And Multiple-using Businesses Facilities consist of two regulations engaged in the kind of law and the size of the floor area. One building can not be based on operating facilities and together in Multiple use businesses Law. As such, the Buildings are applied to the Building codes, Fire Protection laws, such as Multi-using Businesses Facilities interior construction industry due to the structural differences in the position of the designer feeling a lot of difficulties and confusion. The Multi-use businesses Facilities engage in the kind of law, the size of the floor area and seating capacity. These can not be based on operating facilities, and consists of two regulations together in one building. This study is purposed to help improving the finish of the interior architecture that is related to the Building code regulations, Fire Protection laws, Multi-using Facilities interior finishing material relevant with the provisions from the law through analyze the case of developed countries, and the current Multiple use Businesses Facilities research range from the law of multiple-using facilities, interior finishing, interior architecture for supervision reasonably and compensation for the interior design. So, Result is as follows: First, interior decorations can be separated the fixed material and the moveable things. second, It should be included multi-using Business though small size business space at the basement floor. third, It should be established statute law that design and construction responsibility. forth, re-testing fire resist performance after some period. and finally, it need to mitigate regulation where be installed sprinkler.

• Journal of Adhesion and Interface
• /
• v.15 no.2
• /
• pp.63-68
• /
• 2014

Hollow mesoporous carbon nitride material with sphere shape was synthesized using polystyrene sphere as template and cyanamide as nitrogen and carbon atom sources via thermal treatment process. The process of the silica removal is not necessary because silica as template is not in use for the synthesis of hollow mesoporous carbon nitride material and any solvents are also not in use. The size of polystyrene spheres was about 170 nm. Hollow diameter and wall thickness were 82 nm and 13 nm, respectively, in hollow mesoporous carbon nitride sphere. Surface area, mesopore size and pore volume of hollow mesoporous carbon nitride material was $188m^2g^{-1}$, 3.8 nm and $0.35cm^3g^{-1}$, respectively. The wall in hollow sphere has graphitic structure. Hollow mesoporous carbon nitride material has potential applications in the area of fuel cell, catalysis, photocatalysis, electroemmision device, etc.

• Korean Journal of Plant Resources
• /
• v.13 no.2
• /
• pp.124-130
• /
• 2000

In an effort to produce high quality Angelica gigas NAKAI in the southern area of Korea, a variety of mulching materials were used to prevent withering during the summer. The experimental results are summarized as follows. Soil water content and temperature under various mulching materials were higher than those without mulching, in all the cases studied. Among various mulching materials P. E.(polyethylene) mulching material showed the highest effect. The appearance of weeds was the lowest when using the black P. E. mulching, while growth of weeds was the greatest when using transparent mulching. Growth and development of the plant were better with P. E. mulching than straw mulching or no mulching, allowed for more and bigger leaves. The bolting rate was about 2∼5%, with a slightly larger value under P. E. mulching. Under P. E. mulching, probably due to good physical properties of the soil the number of roots was large, and the length and diameter were good. Active growth of roots under P. E. mulching resulted in a yield increase of the plant. The black P. E. mulching material showed a prominent effect on suppression of weed growth, and the black P. E. material was considered to be the most recommendable among various P. E. mulching materials when there is a lack of labor.

• Restorative Dentistry and Endodontics
• /
• v.46 no.1
• /
• pp.5.1-5.13
• /
• 2021

Objectives: The aim of the current study was to assess whether the amount of extruded debris differs for straight and severely curved root canals during retreatment using H-files, R-Endo, Reciproc and ProTaper Universal Retreatment (PTU-R) files. Additionally, the area of residual filling material was evaluated. Materials and Methods: Severely curved (n = 104) and straight (n = 104) root canals of maxillary molar teeth were prepared with WaveOne Primary file and obturated with gutta-percha and AH Plus sealer. Root canal filling materials were removed with one of the preparation techniques: group 1: H-file; group 2: R-Endo; group 3: Reciproc; group 4: PTU-R (n = 26). The amount of extruded material and the area of the residual filling material was measured. The data were analyzed with 2-way analysis of variance (ANOVA) and 1-way ANOVA at the 0.05 significance level. Results: Except for Reciproc group (p > 0.05), PTU-R, R-Endo, and H-file systems extruded significantly more debris in severely curved canals (p < 0.05). Each file system caused more residual filling material in severely curved canals than in straight ones (p < 0.05). Conclusions: All instruments used in this study caused apical debris extrusion. Root canal curvature had an effect on extruded debris, except for Reciproc system. Clinicians should be aware that the difficult morphology of the severely curved root canals is a factor increasing the amount of extruded debris during the retreatment procedure.

• The Journal of Korea CHUNA Manual Medicine
• /
• v.5 no.1
• /
• pp.183-193
• /
• 2004

Objective : Acupuncture therapy is known as a effective method to pain control including elbow area pain. To make clear about effectiveness of acupuncture affecting to recovery of grip power for the patient with elbow area pain, we compare the patients recieved acupuncture treatment to people with elbow pain unrecieved acupuncture treatment. Material and Methods : This clinical study has been carried out with 30 cases of patients with elbow area pain. 20 patients divides into two groups were treated by acupuncture in MPS with elbow area. Two groups were radial area pain group and ulnar area pain group. The other 10 people with elbow area pain working a resturant in Ilsan were no treatment. The study was applicated and estimated grip power before 1 st treatment and after each treatment for 4 days. Results : 1. In the radial area pain group, the acupuncture treatment is more effective than no treatment (p<0.007). 2. In the ulnar area group, the acupuncture treatment is more effective than no treatment (p<0.037). 3. The effectiveness of acupunctrue treatment is no differnce between radial area pain and ulnar area pain(P<0.529) 4. In the elbow area pain group, the acupuncture treatment is more effective than no treatment (p<0.001). Conclusion : These results shows that acupuncture treatment is effective in elbow area pain.

• Journal of Periodontal and Implant Science
• /
• v.47 no.6
• /
• pp.388-401
• /
• 2017

Purpose: The physicochemical properties of a xenograft are very important because they strongly influence the bone regeneration capabilities of the graft material. Even though porcine xenografts have many advantages, only a few porcine xenografts are commercially available, and most of their physicochemical characteristics have yet to be reported. Thus, in this work we aimed to investigate the physicochemical characteristics of a porcine bone grafting material and compare them with those of 2 commercially available bovine xenografts to assess the potential of xenogenic porcine bone graft materials for dental applications. Methods: We used various characterization techniques, such as scanning electron microscopy, the Brunauer-Emmett-Teller adsorption method, atomic force microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and others, to compare the physicochemical properties of xenografts of different origins. Results: The porcine bone grafting material had relatively high porosity (78.4%) and a large average specific surface area (SSA; $69.9m^2/g$), with high surface roughness (10-point average roughness, $4.47{\mu}m$) and sub-100-nm hydroxyapatite crystals on the surface. Moreover, this material presented a significant fraction of sub-100-nm pores, with negligible amounts of residual organic substances. Apart from some minor differences, the overall characteristics of the porcine bone grafting material were very similar to those of one of the bovine bone grafting material. However, many of these morphostructural properties were significantly different from the other bovine bone grafting material, which exhibited relatively smooth surface morphology with a porosity of 62.0% and an average SSA of $0.5m^2/g$. Conclusions: Considering that both bovine bone grafting materials have been successfully used in oral surgery applications in the last few decades, this work shows that the porcinederived grafting material possesses most of the key physiochemical characteristics required for its application as a highly efficient xenograft material for bone replacement.

• The Journal of Engineering Geology
• /
• v.15 no.2 s.42
• /
• pp.105-121
• /
• 2005

Most of the landslides triggered by intensive rainfall on natural slope occur serious damages of human beings and properties. There have been many landslides since 1991 in Gyeonggi province. The influential factors are rainfall, topography, geology and soil properties. There were 660 landslides occurred by intensive rainfall as much as 250mm at Yongin and Anseong area from Tuly 19th to luly 21st,1991 This study surveyed location, topography, geology, geometry of the landslide and rainfall at the area and analyzed occurrence characteristics of the landslides. Most of the landslides occurred on the soil layer above the bed rock. They showed changes of landslide types from translational slides at the head part to flow at the central part. The landslides have relatively small magnitude of which length is shorter than 50m. In order to identify characteristics of landslides dependent on soil conditions, geotechnical properties of soil were evaluated by laboratory tests using soil samples which were collected on slided area and not-slided area. Soil properties of the slided area show high percentage of coarse material such as gravel and sand. However, soil of the not-slided area is mainly composed of fine material such as silt and clay. Permeability coefficients of the slided area are higher than those of the not-slided area.

• The Korean Journal of Food And Nutrition
• /
• v.34 no.5
• /
• pp.458-467
• /
• 2021

The effect of 16 cultivars on the quality of the rice porridge was investigated. The 'Geunnun' had the highest water absorption rate, but the 'Segyejinmi' yield (w/w) was the highest. The total sugar content of the rice porridge was 0.29~8.10%, showing significant variation among the cultivars. High amylose 'Dodamssal' and 'Hwaseonchalbyeo' glutinous rice displayed rotational viscosities of <20,000 cP. Rotational viscosities for boiled rice cultivars were 30,000~40,000 cP, representing an intermediate level, and the rotational viscosities of 'Geonyang2' and 'Hanareum4' were over 50,000 cP. These results suggest that the viscosity of rice porridge varies significantly among raw material cultivars. Among other variables affecting the texture profile of rice porridge, there were significant differences in hardness and gumminess among the cultivars. As a raw material, 'Baekokchal', a kind of glutinous rice, is known to be whiter than the non-glutinous rice, but after processing to porridge, it showed the lowest L value (71.1). Starch degrading enzyme activity was not significant in most types of rice porridges within 30 or 60 minutes. Therefore, enzymatic starch degradation is thought to be completed within 30 minutes. Among the tested raw materials, 'Miho' was 73.5 ㎍/mg, indicating the best digestibility in vitro.