• Transactions of Materials Processing
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• v.27 no.6
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• pp.347-355
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• 2018

This study investigated the effects of the processing number of multi-axial diagonal forging (MADF) on the microstructural changes of OFC fabricated by MADF processes. The as-extruded OFC was cut to $25mm^3$ cube for the MADF processes. The MADF process consists of plane forging with a thickness reduction of 30% and diagonal forging with a diagonal forging angle of $135^{\circ}$. In order to analyze the microstructural evolutions according to the number of repetitions, 1, 2, 3 and 4 cycles of the MADF process were performed. OFC specimens were successfully deformed without surface cracking for up to 4 cycles of MADF. The grain size, average misorientation and average grain orientation spread (GOS) of MADF processed materials were analyzed using EBSD technique and their Vicker's hardness were also measured. The results showed that MADF process effectively refined the microstructure of OFC with initial average grain size of $84.2{\mu}m$. The average grain sizes of specimens MADF processed for 1, 2, 3, 4 cycles were refined to be $8.5{\mu}m$, $2.2{\mu}m$, $1.5{\mu}m$, $1.1{\mu}m$, respectively. The grain refinement seemed to be saturated when OFC was MADF processed over 2 cycles. In the case of specimens subjected to two or more cycles of MADF, the degree of decrease in average grain size was drastically reduced as the number of cycles increased due to softening phenomena such as dynamic recovery or dynamic recrystallization during processing. The degree of increase in average Vicker's hardness was also dramatically reduced as the number of cycles increased due to the same reason.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.36.1-36.1
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• 2010

OFC (Optical Frequency Comb) is an optical spectrum which consists of equidistant lines in frequency space. OFC can thus be used as an optical ruler. Since it was demonstrated in late 1990s, it is revolutionizing many fields in frequency metrology such as the measurement of absolute optical frequencies, the measure ratios of optical frequencies with extremely high precision. It is also used in high-precision spectroscopy. In astronomy, OFC can be used as a very accurate and stable wavelength standard for a high resolution spectrograph to measure the radial velocity of celestial bodies with extremely high accuracy of about several tens cm/s. In our presentation, we will introduce some basic concepts of OFC and some issues to use it in astronomical spectrograph. We will also present our plan to develop a high resolution spectrograph with OFC.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.5
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• pp.483-489
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• 2018

Recently proposed organic flash cycle (OFC) was shown to potentially improve power generation using low grade heat source. In this paper, a thermodynamic performance is carried out for a modified OFC employed double expansions. Effects of the selection of working fluid and the important system parameters such as the temperatures in flash evaporators on the system performance were extensively investigated. Results showed that the system performances are strongly influenced with the system parameters and selection of the working fluid, and the power generation can be increased compared to the basic OFC.

• The korean journal of orthodontics
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• v.33 no.3 s.98
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• pp.185-197
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• 2003

This study was performed to identify the characteristics of the OFC1 gene (locus: chromosome 6p24.3) in Korean patients, which is assumed to be the major gene behind the nonsyndromic cleft lip and palate. The sample consisted of 80 subjects: 40 nonsyndromic cleft lip and palate patients (proband, 20 males and females, mean age 14.2 years); and 40 normal adults (20 males and 20 females, mean age 25.6 years). Using PCR-based assay, the OFC1 gene was amplified, sequenced, and then searched for similar protein structures. Results were as follows: 1. The OFC1 gene contains the microsatellite marker 'CA' repeats. The number of the reference 'CA' repeats was 21 times, and formed as TA(CA)11TA(CA)10. But, in Koreans, the number of tandem 'CA' repeats was varied from 17 to 26 except 18, and 'CA' repeats consisted of TA(CA)n. 2. Nine allelic variants were found. Distribution of the OFC1 allele was similar between the patients and control group. 3. There was a replacement of the base 'T' to 'C' after 11 tandem 'CA' repeats in Koreans compared with Weissenbach's report. However, the difference did not seem to be the ORF prediction results between Koreans and Weissenbach's report. 4. The BLAST search results showed the Telomerase reverse transcriptase (TERT) and the Nucleotide binding protein 2 (NBP2) as similar proteins. The TERT was a protein product by the hTERT gene in the locus 5p15.33 (NCBI Genome Annotation; NT023089) The NBP2 was a protein product by the ABCC3 (ATP-binding cassette, sub-family C) gene in the locus 17q22 (NCBI Genome Annotation; NT010783). 5. In the Pedant-Pro database analysis, the predictable protein structure of the OFC1 gene had at least one transmembrane region and one non-globular region.

• Journal of Life Science
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• v.13 no.6
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• pp.865-870
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• 2003

Opuntia ficus-indica is widely used as folk medicine for burned wound, edema and indigestion, etc. After the adaptation of rats for seven days, OF (200mg/kg) was administered into rats intraperitoneally every day for two weeks. On the 14th day, $3.3m\ell$ of $CCl_4$ (50% $CCl_4$ : Olive oil = 1 : 1) was treated to rats and on the 15th day, they were operated. We measured the levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, total lipid and triglyceride (TG) in serum and Malondialdehyde (MDA) in liver tissue. Opuntia ficus-indica and $CCl_4$-treated group (OFC) significantly decreased lipid peroxidation by 32.6% compared to $CCl_4$-treated abnomal group (CTA). Total lipid and TC of OFC administered group were lower than those of CTA group. Cholesterol levels showed significant effect in OFC group. Total cholesterol and LDL-cholesterol in OFC administered group were decreased by 12.7% and 17.4%, respectively, compared to those of CTA group. HDL-cholesterol in OFC administration group was increased by 19.7% compared to CTA group. This finding suggests that lipid peroxidation was inhibited in the significant level when $CCl_4$-induced rats were treated with OF. Based on this analysis, further study to identify the active components in this sample is warranted.

• Photonics industry news
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• s.58
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• pp.34-37
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• 2010

• Transactions of Materials Processing
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• v.29 no.1
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• pp.5-10
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• 2020

Heat treatment conditions of 88.5% asymmetrically cold rolled oxygen free copper (OFC) sheets have been studied to obtain an equiaxed fine microstructure with a grain size of less than 10 ㎛. The commercial OFC sheets with the thickness of 10 mm were asymmetrically cold rolled by using equal speed asymmetric rolling (ESAR) processes and total rolling reduction. The thickness of the rolled sheets were 88.5% and 1.15 mm, respectively. An equiaxed fine microstructure of OFC sheets with a grain size of 6.0 ㎛ were obtained when the asymmetrically cold rolled OFC sheets were heat treated at 180℃ for 40 minutes. The tensile strength of the asymmetrically cold rolled specimen increased from 217.6 MPa to 396.1 MPa, while the elongation of the specimen asymmetrically cold rolled and heat treated increased from 29.0% to 66.9% along with an 8% increase of the tensile strength.

• Clinical and Experimental Pediatrics
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• v.57 no.2
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• pp.75-78
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• 2014

Purpose: This study aimed to investigate the clinical features of macrocephaly at birth in Korea using ultrasonography. Methods: We retrospectively investigated the medical records of full-term birth neonates in Cheil General Hospital & Women's Healthcare Center from January 2000 to June 2012. The following parameters were recorded and analyzed: gestational age, sex, birth weight, height, occipitofrontal circumference (OFC), physical examination, perinatal problems, and ultrasonography results. Macrocephaly was diagnosed when the OFC was greater than two standard deviations, based on the 2007 Korean National Growth Charts. Results: There were 75 neonates with macrocephaly at birth (52 boys and 23 girls), with a mean OFC of $38.1{\pm}0.49cm$. A comparison of the birth weight and height with the OFC value showed that height was correlated with OFC (r=0.35) but birth weight was not correlated with OFC (r=0.06). There were no remarkable findings in 56 cases (75%). Germinal matrix hemorrhage was identified in 10 cases (13%). An enlarged cerebrospinal fluid space was found in 5 cases (6.7%). There were 3 cases of mega-cisterna magna (4%), 1 case of ventriculomegaly, and 1 case of an enlarged interhemispheric space (6 mm) among these patients. In addition, a choroid plexus cyst was seen in 1 case. Mineralizing vasculopathy in both basal ganglia with no evidence of congenital infection was found in 2 cases and an asymptomatic subarachnoid hemorrhage was found in 1 case. Conclusion: Our results indicate that macrocephaly at birth has benign ultrasonography findings and shows a pattern of male dominance.

• Transactions of Materials Processing
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• v.27 no.4
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• pp.250-256
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• 2018

Oxygen-free copper (OFC) was prepared as a 90 mm cube and then processed with Multi-Axial Diagonal Forging - Initialization of Prior manufacturing History (MADF). The MADF process has been newly developed as a severe plastic deformation method. The MADF process consists of upset forging with a thickness reduction of 30% and diagonal forging with a diagonal angle of $135^{\circ}$. 1 cycle process consists of a 12 passes forging process. In order to analyze the characteristic changes according to the number of iterations, 1, 2, and 3 cycles of the MADF process were performed. The OFC specimens were MADF processed without surface cracks up to 3 cycles. The microstructure, hardness and tensile test of processed materials were analyzed to study the change of material properties according to the amount of MADF process. The results showed that the MADF process effectively refined the microstructure and increased the strength of OFC. In the case of specimens processed for more than 2 cycles, the grains of all measurement regions were refined to be less than $7{\mu}m$ of grain size. The 1 cycle MADF processed OFC showed the highest mechanical properties with the hardness of 132 HV and tensile strength of 395 MPa. Hardness and strength seemed to be saturated when processed over 2 cycles.

• Anxiety and mood
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• v.2 no.2
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• pp.94-100
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• 2006

Objective : This study was designed to examine the volumetric abnormality of orbitofrontal cortex (OFC) and its change after 2 years of pharmacotherapy in obsessive compulsive disorder (OCD) patients. Method : Volumetric magnetic resonance imaging studies were conducted in 15 OCD patients and 13 normal volunteers. For 2 years, all patients took at least one serotonin reuptake inhibitor and atypical antipsychotics were used as an augmentation therapy in most patients. The follow-up MRI studies were conducted after the pharmacotherapy and OFC volumes were measured by the manual region of interest method. Results : Bilateral OFC volumes of 15 OCD patients were significantly greater than those of the normal volunteers before the treatment. After 2 years of the treatment, significant decrease was observed in bilateral OFC volumes of OCD patients to the extent that left OFC volume of OCD patients was not different from that of the normal volunteers. Conclusion : This finding suggests that OFC is directly related to the pathophysiology of obsessive compulsive disorder.