• Journal of the Korean Society for Heat Treatment
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• v.32 no.1
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• pp.17-28
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• 2019

Jominy hardenability curves of low alloy steel containing less than 5 wt.% of alloying elements in total were calculated by applying Scheil's rule of additivity to pre-calculated isothermal transformation curve. Isothermal transformation curve for each phase in steel was approximated as a simple mathematical equation by using Kirkaldy's approach and all coefficients in the equation were estimated from experimental temperature-time-transformation (TTT) and/or continuous cooling transformation (CCT) data in the literature. Then jominy test with simple boundary conditions was performed in computer by applying the finite difference scheme. The resultant cooling curves at each location along a longitudinal direction of Jominy bar were applied to calculate phase fractions as well as mechanical properties such as micro Vickers hardness. The simulated results were compared with experimental CCT data and Jominy curves in the literature.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.581-586
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• 2005

High-performance concrete (HPC), which is particularly sensitive to self-desiccation, is required to be durable even in severe environmental conditions, i.e. costal area, cold district, etc. However, in recent years, some attention was particularly given to cracking sensitivity of high performance concrete at early age. It has been argued and demonstrated experimentally that such concrete undergoes autogenous shrinkage due to self-desiccation at early age under restrained condition, nd, as a result, internal tensile stress may develop, leading to micro cracking and macro cracking. This shrinkage-introduced crack produces a major serviceability problem for concrete structures. One possible method to reduce cracking due to autogenous shrinkage is the addition of expansive additive. Tests conducted by many researches have shown the beneficial effects of addition of expansive additive for reducing the risk of autogenous shrinkage-introduced cracking. However, the research on hydration model of expansion additive has been hardly researched up to now. This paper presents a study of the hydration model of Ettringite-Gypsum type expansive additive. As a result of comparing forecast values with experiment value, proposed model is shown to expressible of hydration of expansive additive.

• Journal of Life Science
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• v.19 no.2
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• pp.289-298
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• 2009

Effects of Nattokinase fibrinol (NKF), defined as a fibrinolytic product, on fibrinolytic and atherogenetic markers were studied for healthy adults (20-31 years old), who is smoking more than 20 cigarettes per day. Subjects were divided into 29 for NKF group and 10 for placebo group in a short term study. They were given 2 tablets of NKF (4,000 unit) or placebo tablet and thereafter blood samples were collected at 0, 2, 4 hr prerid. For a 4-week long term study, 15 subjects for NFK group and 10 subjects for placebo group were supplemented one tablet of each NKF (2,000 unit) and placebo per day, respectively. Blood samples were collected at 0, 1, 2, 4 weeks later. The short-term experimental trial showed that NKF remarkably increased fibrinolytic activity at 2hr after consumption, which was maintained up to 4 hr, relative to that of placebo, while NKF reduced the euglobulin clot lysis time (ECLT) and retarded the activated partial thromboplastin time (aPTT), as compared to placebo group. NKF supplementation for 4 weeks elevated fibrinolytic activity, shortened ECLT and retarded aPTT. Furthermore, NKF supplementation increased anti-atherogenic index by decreasing triglyceride (TG) and elevating high-density lipiprotein (HDL)-cholesterol. These results indicate that NKF supplementation for short term or long term might have beneficial effects on preventing and treating cardiovascular disease by increasing fibrinolytic activity and improving atherogenic markers such as hyperlipidemia.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.729-737
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• 2019

Fatty pancreas is an abnormal process of lipid deposition in cells, resulting in increased fat tissue and obesity. The result is a risk factor for cardiovascular and metabolic diseases. The aim of this study was to evaluate the usefulness of pancreatic fat as a predictor of cardiovascular disease and metabolic syndrome in pancreatic ultrasonography. In 407 patients who underwent a comprehensive screening at the W Health Care Center in Busan from September 2. 2018 to December 31, 2018, the degree of fat deposition in the pancreas was evaluated as the degree of mild, moderate. Data on non-obstructive atherosclerosis, BMI, hyperlipidemia, hypertension, and diabetes were collected to assess the association of pancreatic fat deposition with cardiovascular disease and metabolic syndrome. In addition, we tried to analyze the correlation between liver dysfunction and thyroid dysfunction as the degree of fat pancreas increased. We examined the relationship between six parameters including atherosclerosis, BMI, hyperlipidemia, hypertension, diabetes, liver dysfunction, and thyroid dysfunction among patients with fatty pancreas. We concluded that the carotid intima-media thickness of atherosclerosis, which is a risk factor of cardiovascular disease, is most closely related to fatty pancreas.

• Korean Journal of Materials Research
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• v.3 no.6
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• pp.606-613
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• 1993

This was studied about aging characteristic of AC4A/$SiC_{w}$ 10-30v/o reinforced composite. Aging hardenability was decreased $SiC_{w}$ 30% > 10% > 20%. Aging hardening of T6 treatmented composite was higher absolute value than AC4A I/M material. And this results indicated initial hardening phenomenon according to increase $SiC_{w}$ volume fraction. Reinforced effect by pressure was the same effect as before aging treatment and the best condition pressure at 75MPa. Similar to reinforced effect according to $SiC_{w}$ volume fraction was 30 % > 10 % > 20 %. In case of pressure is low, whisker is not break the same time press with base metal after wetting. After it is wetting with base metal, a part transformed or wetting part break and whisker maintain original shape or a part transformed on the otherhand, in case of pressure is high, whisker is break in same time it was not against pressure and whisker's shape is near a polygon or spherical shape.

• Elastomers and Composites
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• v.48 no.4
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• pp.249-255
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• 2013

Hydroxypropyl terminated PDMS was synthesized by the hydrosilylation reaction with allyl alcohol in the presence of Karstedt's catalyst. And them, an one-pot reaction with HDI isocyanurate trimer and hydroxyethyl methacrylate was conducted to give a silicone-modified urethane acrylate oligomer (PUA oligomer) having 9000 g/mol, weight average molecular weight. The synthesized PUA oligomer was characterized by using FT-IR and GPC. The UV-curable coatings were prepared by PUA oligomer blending with a reactive monomer (phenylthioethyl acrylate) under the different mole ratios. It was found that the refractive index of cured film increased when the reactive monomer was added but there was no relationship between the refractive index and amount of reactive monomer. Also, their transmittance for cured films was not change as increasing the content of reactive monomer.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.498-505
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• 2004

Purpose: We compared captopril renal scintigraphic criteria for the diagnosis of renovascular hypertension by unilateral renal artery stenosis. Materials and Methods: The study group consisted of 24 patients (m/f : 16/8, age: $39{\pm}18$ years) with unilateral renal artery stenosis who underwent renal artery revascularization and captopril renal scintigraphy with $^{99m}Tc$-diethylenetriaminepentaacetic acid between May 1995 and April 2004. The blood pressure response was classified as cure/improvement or failure. We evaluated captopril-induced changes in relative function (BCfun) and renogram grade (0 to 5: 0=normal, and 5=renal failure pattern without measurable uptake) (CBren) and the difference of renograms between the normal and stenotic kidney on captopril scan (CNren). Results: light of 24 patients were cured and 11 improved and 5 patients were classified as failed revascularization. Significant predictors of a cure or improvement of blood pressure were younger age, stenosis by fibromuscular dysplasia or arteritis, BCfun, CBren and CNren. Areas under the receiver operating characteristic curve of age, BCfun, CBren and CNren were not significantly different. Positive and negative predictive values of predictors were 100% and 42% (age ${\leq}38$): 92% and 50% (BCfun ${\geq}1%$): 92% and 75% (CBren ${\geq}1$), and 90% and 60% (CNren ${\geq}1$), respectively. Conclusion: Captopril induced changes in renal function and renogram can reliably predict hypertension response to revascularization. Renogram pattern on captopril scan can diagnose renovascular hypertension without baseline data in patients with unilateral renal artery stenosis.

• Journal of Sericultural and Entomological Science
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• v.48 no.2
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• pp.41-45
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• 2006

Mulberry leaves contain many natural components and are considerable resource for natural antiokidants. The antioxidant effect of 'Cheongilppong' collected from Chuncheon, Suwon and Wanju regions were investigated with minilum L-100 device and ARAW-KIT (anti-radical ability of water-soluble substance), in comparison to the ascorbic acid. The measurement parts were mulberry leaves collected from different areas and some kinds of mulberry branches. We obtained that even if samples were same variety, antioxidant capacity of those showed different results according to collected regions. Also, antioxidant effect of mulberry leaves were higher than that of branches. The order of antioxidant effect in Spring was Chuncheon > Suwon > Wanju. The antioxidant effect of mulberry leaves collected from Chuncheon, Suwon and Wanju regions of just before the coloration stage with anthocyanin in fruits were 3627.5 nmol, 2620.0 nmol 1360.7 nmol (ascorbic acid equivalents), respectively. In Autumn, the antioxidant effect and hardness quality of mulberry leaves were increased gradually until just before fallen leaves stage. Therefore, we concluded that being the most suitable period for collecting mulberry leaves as a antiokidant resource is from the latter part of May to the first ten days of June.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.2
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• pp.144-152
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• 2016

Carotid-artery stenosis may reduce cerebral perfusion, and affect cerebral neuronal activities. We examined the question of whether the recovery of cerebral-perfusion reserve after carotid-artery stenting (CAS) can affect the EEG power-spectrum. Nineteen candidates for CAS were initially recruited. Subtraction imaging of single photon emissary computerized tomography (SPECT) and an electroencephalogram (EEG) were taken twice, before and 1 month after CAS. At each time point, the EEGs were recorded before and after injection of acetazolamide (pre-ACZ EEG and post-ACZ EEG). Finally, 7 patients were enrolled after exclusion of incomplete studies. We obtained the spectral ratio (SR) of each hemisphere. SR was defined as the divided value of the power-spectrum sum of fast activities by that of slow activities. The power-spectrum values between hemispheres were compared using the inter-hemispheric index of spectral ratio (IHISR), and we examined the correlation between the power-spectrum and the cerebral-perfusion reserve. Cerebral-perfusion reserve improved after CAS on the stent side in 6 of 7 patients. In 3 patients with unilateral carotid-artery stenosis, CAS increased SR on the pre-ACZ EEGs, and IHISR on the post-ACZ EEGs. The increases of SR and IHISR were concordant with the increment of cerebral-perfusion reserve. In contrast, the results in the other patients with bilateral stenosis showed complex patterns. The SR of pre-ACZ EEGs and IHISR of post-ACZ EEGs may be useful electrophysiological markers for the blood-flow reserve after CAS in patients with unilateral carotid-artery stenosis, but not in those with bilateral stenosis.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.615-620
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• 2015

The high performance fiber reinforced cementitious composite (HPFRCC) controls the cracking development of the structure by inducing micro-cracking and strain hardening behavior after the initial cracking under the tensile conditions. Although, in Korea, the research about manufacturing the single-fiber reinforced cementitious composite or the mechanical properties of hardened status has been conducted, the research to apply the HPFRCC with multi-fiber is not sufficient. Hence, in this research, considering the workability and economic aspect for practical applications, the engineering properties of HPFRCC with combined long steel fiber (SL) and long organic fiber (OL) are evaluated such as workability and strength. As a result of evaluating the engineering properties of HPFRCC, the most favorable performance was obtained when the mixture contained 1.5% of combined SL and OL.