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國産스테인레스鋼線系 矯正用線材의 開發과 物理的 性質에 關한 硏究
권오원,성재현,이기대,경희문 대한치과교정학회 1989 대한치과교정학회지 Vol.19 No.2
The physical properties of seven sizes of control groups and experimental group in stainless steel orthodontic wires were studied in tension, hardness, bending, torsion and observation of microstructure. The wires (0.40 - 0.90mm dia.) of round type were tested in the as-received condition. The wires of control groups were TRU-CHROME and REMANIUM, and experimental group was SK wire which was developed by ourselves and made in Korea. The results were as follows: 1. The chemical compositions of control groups and experimental group were austentie stainless steel wires of SOS 304. 2. Higher values of tensile and yield strength in tension were control group I, experimental group, control group II. Maximum tensile and yield strength of experimental group were 203.63 ±1.41kg/mm²in 0.70mm diameter and 148.96 ± 4.88kg/mm² in 0.60mm diameter, and maximum elongation was 5.20 ± 0.57% in 0.45mm diameter. 3. Hardness values of experimental group were similar to control groups. Maximum hardness values were 596.2 ± 13.66 Hv in 0.45mm diameter wire of control group I, 590.5 ± 20.08Hv in 0.50 mm diameter wire of control group II, and 563.6 ± 5.35 Hv in 0.70mm diameter wire of experimental group. 4. Torsion properties of experimental group were similar to control group I and more than control group II. Maximum torsion cycles were 31.8 ± 2.48 in 0.45mm diameter of control group I,17.4 ± 4.84 in 0.60mm diameter of control group II, and 24.6 ± 3.04 in 0.45mm diameter of experimental group. 5. Maximum bending cycles of experimental group were smaller than control groups. Maximum bending cycles were 9.00 ± 0.00 in 0.50mm diameter wire of control group I, 10.0 ± 0.82 in 0.40mm diameter wire of control group II, and 8.0 ± 1.26 in 0.50 mm diameter wire of experimental group. 6. Microstructures of experimental and control groups co-existed with martensited austenite structure and elongated austenite structure. 7. The direction of wire fracture was propagated parallel to torsion direction typically and there was no probability showing wire fracture at inclusions and surface scratches. 8. The type of wire fracture was brittle fracture at initiation site and ductile fracture at core.
權五源,徐惠敬,李基大 慶北大學校 齒科大學 1987 慶北齒大論文集 Vol.4 No.1
According to the development of the techniques for tooth movement, the research on the orthodontic wires has advanced and the Ni-Ti wire is highlighted these days. The Superelasticity of Ni-Ti wires was studied in tension. The wires were tested by universal testing machine. The elastic modulus was 20×10 exp (3)kg/㎟ in Cr-Ni wires, 21∼25×10(3)kg/㎟ in Co-Cr wires and 5∼6×10 exp (3)kg/㎟ in Ni-Ti wires. The elastic modulus of Ni-Ti wires was opproximately 1/4 of Cr-Ni wires and Co-Cr wires, and the elastic limit of Ni-Ti wires was approximately 4 times of Cr-Ni wires and Co-Cr wires. The permanent strain was approximately 0.5% in stress-strain curve of Ni-Ti wires.
李基大,權五源,成材鉉 慶北大學校 齒科大學 1985 慶北齒大論文集 Vol.2 No.1
The physical properties of .016" orthodontic wires by heat treatment were studied in tension, bending, hardness and microstructures. The wires were tested in the as-manufactured and heat-treated conditions. The results were as follows: Ultimate tensile strength and yield strength were slightly increased by heat treatment, but Elgiloy was the most effective by geat treatment. The strength of Elgiloy showed the highest value after heat treatment above 6 minutes at 500, 600℃. Also, bending fluxure modulus of elasticity were progressively increased by heat treatment. the hardness number of Australian of as-manufactured wires showed the highest value, and Elgiloy showed the highest value by heat treatment. Microstructure of as-manufactured wires showed fibrous interlocking grains, and a coarse grains after heat treatment and an austenite structure after solution heat treatment.
MIN-MAX SOFM과 객체 분석을 이용한 얼굴 검출 알고리즘 개발
하성욱,강대성,권기항 東亞大學校 附設 情報通信硏究所 1998 情報通信硏究所論文誌 Vol.6 No.1
This paper proposes a face region detecting algorithm in stream images. The main limitation of current face detection researches is the front face detection. But, the face detection in stream images needs to extract features in various angles. Current algorithms also are not enough to be applied to the real world from the several limited arguments as uniform luminous intensity, simple background, etc. This reserch suggests a detection algorithm of stream face images which is regardless of these limit arguments. The firs stage supports a proposition of MIN-MAX SOFM(self organizing feature maps) by applied MIN-MAX theory in SOFM which is independent on luminous intensity. After the first stage, the small regioin removing algorithin is processed for loss regions in SOFM output mode. We propose a histogram object analysis method which selects speedy recognized regions and a frame based moving detection method by moving real images.
Kwon, Dae Kee,Kang, Jung Taek,Park, Sol Ji,Gomez, Ma Ninia Limas,Kim, Su Jin,Atikuzzaman, Mohammad,Koo, Ok Jae,Jang, Goo,Lee, Byeong Chun Cambridge University Press 2011 Zygote Vol.19 No.3
<B>Summary</B><P>In non-human primates, it is difficult to collect sufficient numbers of oocytes for producing identical embryos by somatic cell nuclear transfer (SCNT). Because of this factor, inter-species SCNT (iSCNT) using heterospecific oocytes is an attractive alternative approach. The objective of this study was to produce iSCNT-derived blastocysts using enucleated cow (<I>Bos taurus</I>) metaphase II oocytes and adult rhesus monkey (<I>Macaca mulatta</I>) fibroblasts. Ear skin tissue from a 6-year-old male rhesus monkey was collected by biopsy and fibroblasts were isolated. Immature cumulus-oocyte complexes from cow ovaries were collected and matured <I>in vitro</I> in Medium 199. The enucleated oocytes were reconstructed with rhesus monkey fibroblasts and iSCNT embryos were cultured in modified synthetic oviduct fluid in an atmosphere of 5-5.5% CO2 under various conditions (37-39 °C and 5-20% O2) to examine the effects of <I>in vitro</I> culture conditions. Most embryos were arrested at the 8- or 16-cell stage and only three blastocysts were derived in this way using iSCNT from a total of 1153 cultured activated embryos (0.26% production rate). Two of the three blastocysts were used for counting nuclear numbers using bisbenzimide staining, which were 51 and 24. The other iSCNT-derived blastocyst was used to analyse mitochondrial DNA (mtDNA) by PCR, and both rhesus monkey and cow mtDNA were detected. Although the development rate was extremely low, this study established that iSCNT using two phylogenetically distant species, including a primate, could produce blastocysts. With improvements in the development rate, it may be possible to produce rhesus monkey iSCNT-derived embryonic stem cell lines for studies on primate nucleus and cow mitochondria interaction mechanisms.</P>