• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.379-380
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• 2002

Steam generators (S/G) of pressurized water reactors are large heat exchangers that use the heat from the primary reactor coolant to make steam in the secondary side for driving turbine generators. Reciprocating sliding wear experiments have been performed to examine the wear properties of Incoloy 800 and Inconel 690 steam generator tubes in high temperature water. In present study, the test rig was designed to examine the reciprocating and rolling wear properties in high temperature (room temperature - $300^{\circ}C$) water. The test was performed at constant applied load and sliding distance to investigate the effect of test temperature on wear properties of steam generator tube materials. To investigate the wear mechanism of material, the worn surfaces were observed using scanning electron microscopy. At $290^{\circ}C$, wear rate of Inconel 690 was higher than that of Incoloy 800. It was assumed to be resulted from the oxide layer property difference due to the a\loy composition difference. Between 25 and $150^{\circ}C$ the wear loss increased with increasing temperature. Beyond $150^{\circ}C$, the wear loss decreased with increasing temperature. The wear loss change with temperature were due to the formation of wear protective oxide layer. From the worn surface observation, texture patterns and wear particle layers were found. As test temperature increased, the proportion of particle layer increased.

• The Korean Journal of Ceramics
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• v.2 no.4
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• pp.242-245
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• 1996

The microstructure of $Ba (Zn_{1/3}Ta_{2/3})O_3$ (BZT) was investigated using X-ray diffractometry(XRD) and transmission electron microscopy (TEM). $Ba_{0.5}TaO_3$ and $Ba_3TaO_{5.5}$ (BT) phasses were observed on the surface of the sintered specimen by XRD. Furthermore, a new type of ordering along the [110] direction was found in sintered specimen by the XRD and TEM analysis. The wavelength of ordering was 0.9 nm which is three times larger than the interplanar distance of (110) plane and new type of ordering is considered to be a result of Zn vacancy ordering. The creation of Zn vacancies and formation of BT phases are attributed to the evaporation of volatile ZnO. A new mechanism for ZnO loss is suggested. In this mechanism, only Zn vacancies are created only when the amount of ZnO loss is small and as the amount of ZnO loss increases, BT phases are formed at the same time. A new unit cell of ordered structure is suggested as the superlattics containing three BZT unit cells.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.239-248
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• 2002

Bentonite slurries in a slurry wall construction must fulfill a stabilizing function by forming impermeable membrane (surface cake and penetrated cake) on the excavated soil faces. Thus problems are occurring in practice for the construction of diaphram walls and cut-off walls with a low permeability for wastes disposal areas in some deep excavations or different grounds. In this paper, the fundamental mechanics of fluid loss and filter cake formation in various soil beds are investigated using large scale laboratory apparatus. The sealing efficiency of filter cake from the large scale tests and the significance of fluid loss in a slurry trench are utilized for practical situation as a recommended design procedure.

• Journal of Dairy Science and Biotechnology
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• v.28 no.1
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• pp.17-28
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• 2010

A substantial body of evidence has emerged over the last decade in support of the novel concept that dietary calcium and dairy foods play an important role in regulating energy metabolism and thereby promote healthy weight management and reduce obesity risk. This concept has been demonstrated in experimental animals studies, cross-sectional and prospective population studies and a number of randomized clinical trials. Notably, the effects of dairy foods in weight management are more consistent than the effects of supplemental calcium across clinical trials, and calcium per se is responsible for approximately 40-50% of the effects of dairy. The calcium component is only effective in individuals with chronically low calcium intake, as it serves to prevent the endocrine response to low calcium diets which otherwise favors adipocyte energy storage; calcium also serves to promote energy loss via formation of calcium soaps in the gastrointestinal tract and thereby reduce fat absorption. The calcium-independent anti-obesity bioactivity of dairy resides primarily in whey. The key components identified to date are leucine and bioactive peptides resulting from whey protein digestion. The high concentration of leucine in whey stimulates a repartitioning of dietary energy from adipose tissue to skeletal muscle where it provides the energy required for leucine-stimulated protein synthesis, resulting in increased loss of adipose tissue and preservation of skeletal muscle mass during weight loss. Finally, dairy rich diets suppress the oxidative and inflammatory responses to obesity and thereby attenuate the diabetes and cardiovascular disease risk associated with obesity.

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.173-178
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• 2001

The effects of heat-treatment with magnetic or non-magnetic field on magnetic properties of gas-atomized MPP dust cores subjected to various cooling processes after annealing were investigated. Upon magnetic-field annealing, ac permeability and core loss decreased with the increase of cooling rate, which were attributed to the generation of inhomogeneous internal stress and anomalous eddy current loss, respectively. It was not observed the formation of ordered phase and the related change in magnetic properties at the cooling stage for MPP dust cores. In MPP alloys, magnetic anisotropy was easily induced through the directional order, and permeability and core loss were changed under the conditions of low cooling rate and magnetic annealing.

• Archives of Pharmacal Research
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• v.28 no.1
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• pp.106-110
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• 2005

The preventive effects of Sophorae Fructus extracts (I: hot water extract and II: combination product using I) on bone loss in ovariectomized (OVX) rats were investigated. Sophorae Fructus extracts were orally administrated to OVX rats for 9 weeks. Ovariectomy caused the increase of body weight and deoxypyridinoline (Dpd: bone resorption marker) and decrease of calcium (Ca: bone formation marker) level in serum. Dpd level were significantly decreased and Ca levels were elevated at 9 weeks in Sophorae Fructus extracts administered groups after ovariectomy at a dose of 0.556 g/kg/day compared with control group. In administered groups, trabecular bone area (TBA) in the tibia and lumbar were also increased compared with control group in histomorphological analysis. The preventive or treatment effects of Sophorae Fructus extracts on bone loss in OVX rats appears to be due to suppression of bone turnover.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.230-231
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• 2017

The addition of a limestone filler(LF) to fill into the voids between cement and aggregate particles can reduce the cementitious paste volume. This paper aim to evaluate the influence of LF contents on the hydration kinetics and compressive strength. Hydration kinetics were evaluate using heat of hydration, ignition loss and thermal analysis. The heat of hydration was measured using Isothermal Calorimetry. The degree of hydration was measured using ignition loss. Hydration product analysis was carried out by Thermal Gravimetric and Differential Thermal Analysis. The results show that the addition of LF reduces not only the initial setting time and heat of hydration peak, also degree of hydration and rate of strength development at early age increase with the addition of LF. It can be concluded the LF fills the pore between cement particles due to formation of carboaluminate, which may accelerate the setting of cement pastes.

• Animal cells and systems
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• v.1 no.4
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• pp.583-587
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• 1997

Incubation of an NADPH-dependent succinic semialdehyde reductase from bovine brain with N-bromosuccinimide (NBS) resulted in a time-dependent loss of enzyme activity. The inactivation followed pseudo-first-order kinetics with the second-order rate constant of $6.8\times{10}^3$ $M^-1$ $min^{-1}$. The inactivation was prevented by preincubation of the enzyme with substrate succinic semialdehyde, but not with coenzyme NADPH. There was a linear relation-ship between oxindole formation and the loss of enzyme activity. Spectro-photometric studies indicated that about one oxindole group per molecule of the enzyme was formed following complete loss of enzymatic activity. It is suggested that the catalytic function of succinic semialdehyde reductase is modulated by binding of NBS to a specific tryptophan residue at or near the substrate binding site of the enzyme.

• Archives of Pharmacal Research
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• v.20 no.6
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• pp.637-642
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• 1997

Degradation of a compound with a hydroxyl group during the course of its diffusion across the skin was investigated. Based on the experimental findings of ashortened retention time of a degradant peak from post-diffusion samples and from the ability to evaporate radioactivity from such samples, it seems that during diffusion the parent compound degrades into a more hydrophilic product which is then oxidized. A tritium label at the carbon with a hydroxyl group was released as a tritiated water. When the post-diffusion samples were left open to the air allowing evaporation of water, there was a corresponding decrease in radioactivity of such samples. There was a linear relationship between the time left open and the fraction of radioactivity lost. When such samples were fractionated by HPLC, and then had their radioactivities measured by scintillation counting, two peaks wre identified. The first peak, which may be attributable to tritiated water, was eluted at the same retention time as the solvent front. The second peak eluted at the retention time of the parent compound. When the evaporation/loss of radioactivity experiment was repeated using a $^{14}C$-labeled compound there was no significant loss of radioactivity, indicating that the earlier loss with $^{3}H$-labeled compound was related to the formation and loas sof tritiated water.

• Advances in concrete construction
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• v.7 no.4
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• pp.263-275
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• 2019

In the present work, Granulated Blast Furnace Slag (GBFS) and Fly ash (FA) were used as partial replacement of Natural Sand (NS) and Ordinary Portland Cement (OPC) by weight. One control mix, one with GBFS, three with FA and three with GBFS-FA combined mixes were prepared. Replacements were 50% GBFS with NS and 20%, 30% and 40% FA with OPC. Preliminary investigation on development of compressive strength was carried out at 7, 28 and 90 days to ensure sustainability of waste materials in concrete matrix at room temperature. After 90days, thermo-mechanical study was performed on the specimen for a temperature regime of $200^{\circ}-1000^{\circ}C$ followed by furnace cooling. Weight loss, visual inspection along with colour change, residual compressive strength and microstructure analysis were performed to investigate the effect of replacement of GBFS and FA. Although adding waste mineral by-products enhanced the weight loss, their pozzolanicity and formation history at high temperature played a significant role in retaining higher residual compressive strength even up to $800^{\circ}C$. On detail microstructural study, it has been found that addition of FA and GBFS in concrete mix improved the density of concrete by development of extra calcium silicate gel before fire and restricts the development of micro-cracks at high temperature as well. In general, the authors are in favour of combined replacement mix in view of high volume mineral by-products utilization as fire protection.