• Tunnel and Underground Space
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• v.28 no.1
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• pp.59-71
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• 2018

Since the generalized Hoek-Brown (GHB) function predicts the strength of the jointed rock mass in a systematic manner by use of GSI index, it is widely used in rock engineering practices. In this study, a series of 2D elasto-plastic FE analysis, which adopts the GHB criterion as a yield function, was carried out to investigate the radial convergence characteristics of circular tunnel excavated in the GHB rock mass. The effect of the plastic potential function on the elasto-plastic displacement was also examined. In the analysis, the wide range of both the $K(={\sigma}_h/{\sigma}_v)$ and GSI values are considered. For each K value, the variation of the ratio of sidewall displacement to roof displacement was calculated with varying GSI values and the obtained displacement patterns were analysed. The calculation results show that the displacement ratio significantly depends not only on the K value but also on the range of GSI value. In particular, for lower range of GSI value, the displacement ratio pattern calculated in the elasto-plastic regime is opposite to that predicted by the elasticity theory. In addition, the variation of the radial displacement ratio with GSI value for different types of plastic potential function showed similar trend.

• Clean Technology
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• v.20 no.1
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• pp.42-50
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• 2014

In this study, the $Mg(OH)_2$ slurry was made form ferro-nickel slag and then used for $CO_2$ sequestration. The experiments were in the order as leaching step, precipitation, carbonation experiments. According to the leaching results, the optimal leaching conditions were $H_2SO_4$ concentration of 1 M and the temperature of 333 K. In the $Mg(OH)_2$ manufacturing step, NaOH was added to increase the pH upto 8, the first precipitation was confirmed as $Fe_2O_3$. After removal the first precipitation, the pH was upto 11, the $Mg(OH)_2$ was generated by XRD analysis. The $Mg(OH)_2$ slurry was used for $CO_2$ sequestration. The pseudo-second-order carbonation model was used to apply for $CO_2$ sequestration. The $CO_2$ sequestration rate was increased by the $CO_2$ partial pressure and temperature. However, $CO_2$ sequestration rate was decreased when temperature upto 323 K. After $CO_2$ sequestrated by $Mg(OH)_2$, the $CO_2$ can be sequestrated stable as $MgCO_3$. This study also presented optimal sequestration condition was the pH upto 8.38, the maximum $MgCO_3$ can be generated. This study can be used as the basic material for $CO_2$ sequestration by ferro-nickel slag at pilot scale in the future.

• Advances in nano research
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• v.16 no.4
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• pp.325-340
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• 2024

There are several novel uses for dispersing many nanoparticles into a conventional fluid, including dynamic sealing, damping, heat dissipation, microfluidics, and more. Therefore, melting heat and mass transfer characteristics of a 3-D MHD Hybrid Nanofluid flow over a rotating disc with presenting dufour and soret effects are assessed numerically in this study. In this instance, we investigated both ferric sulfate and molybdenum disulfide as nanoparticles suspended within base fluid water. The governing partial differential equations are transformed into linked higher-order non-linear ordinary differential equations by the local similarity transformation. The collection of these deduced equations is then resolved using a Chebyshev spectral collocation-based algorithm built into the Mathematica software. To demonstrate how different instances of hybrid/ nanofluid are impacted by changes in temperature, velocity, and the distribution of nanoparticle concentration, examples of graphical and numerical data are given. For many values of the material parameters, the computational findings are shown. Simulations conducted for different physical parameters in the model show that adding hybrid nanoparticle to the fluid mixture increases heat transfer in comparison to simple nanofluids. It has been identified that hybrid nanoparticles, as opposed to single-type nanoparticles, need to be taken into consideration to create an effective thermal system. Furthermore, porosity lowers the velocities of simple and hybrid nanofluids in both cases. Additionally, results show that the drag force from skin friction causes the nanoparticle fluid to travel more slowly than the hybrid nanoparticle fluid. The findings also demonstrate that suction factors like magnetic and porosity parameters, as well as nanoparticles, raise the skin friction coefficient. Furthermore, It indicates that the outcomes from different flow scenarios correlate and are in strong agreement with the findings from the published literature. Bar chart depictions are altered by changes in flow rates. Moreover, the results confirm doctors' views to prescribe hybrid nanoparticle and particle nanoparticle contents for achalasia patients and also those who suffer from esophageal stricture and tumors. The results of this study can also be applied to the energy generated by the melting disc surface, which has a variety of industrial uses. These include, but are not limited to, the preparation of semiconductor materials, the solidification of magma, the melting of permafrost, and the refreezing of frozen land.

• Microbiology and Biotechnology Letters
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• v.46 no.4
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• pp.360-371
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• 2018

Extracts and fractions of Anemarrhena asphodeloides Bunge were prepared and their physiological activities and components were analyzed. Antimicrobial activities of the ethyl acetate and aglycone fractions were $78{\mu}g/ml$ and $31{\mu}g/ml$, respectively, for Staphylococcus aureus and $156{\mu}g/ml$ and $125{\mu}g/ml$, respectively, for Pseudomonas aeruginosa. 1,1-Diphenyl-2-picrylhydrazyl free radical scavenging activities ($FSC_{50}$) of 50% ethanol extract, ethyl acetate fraction, and aglycone fraction of A. asphodeloides extracts were $146.2{\mu}g/ml$, $23.19{\mu}g/ml$, and $71.06{\mu}g/ml$, respectively. The total antioxidant capacity ($OSC_{50}$) in an $Fe^{3+}$-EDTA/hydrogen peroxide ($H_2O_2$) system were $17.5{\mu}g/ml$, $1.5{\mu}g/ml$, and $1.4{\mu}g/ml$, respectively. The cytoprotective effect (${\tau}_{50}$) in $^1O_2$-induced erythrocyte hemolysis was 181 min with $4{\mu}g/ml$ of the aglycone fraction. The ${\tau}_{50}$ of the aglycone fraction was approximately 4-times higher than that of (+)-${\alpha}$-tocopherol (${\tau}_{50}$, 41 min). Analysis of $H_2O_2$-induced damage of HaCaT cells revealed that the maximum cell viabilities for the 50% ethanol extract, ethyl acetate fraction, and aglycone fraction were 86.23%, 86.59%, and 89.70%, respectively. The aglycone fraction increased cell viability up to 11.53% at $1{\mu}g/ml$ compared to the positive control treated with $H_2O_2$. Analysis of ultraviolet B radiation-induced HaCaT cell damage revealed up to 41.77% decreased intracellular reactive oxygen species in the $2{\mu}g/ml$ aglycone fraction compared with the positive control treated with ultraviolet B radiation. The findings suggest that the extracts and fractions of A. asphodeloides Bunge have potential applications in the field of cosmetics as natural preservatives and antioxidants.

• Journal of Korean Society of Forest Science
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• v.77 no.2
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• pp.178-185
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• 1988

This study is carried out for analyzing the factors causing several disasters occurring around beach area in order to set a plan for an afforestation which will fulfill its function as facilities for prevention of disasters and for relaxation around beach resort at Tong-ri, Pokil-my$\bar{o}$n, Wando-gun. The results are as follows : 1. The main wind direction was summer was SE. 2. The first class in the rate of frequency of the hourly average wind speed and the instantaneous wind speed in summer were 2.1-3.0m/sec (29.2%) and 1.1-2.0m/sec (30.6%) respectively. 3. The particle sizes of the dune sands was a little small (82.5% in 0.125 to 0.25mm, $D_{50}=0.178mm$). 4. The mineral composition and the chemical components were as follows : The main mineral : Quartz The accessary minerals : Calcite, Feldspars(Orthoclase), Sericite. The chemical components : $SiO_2$ ; 75.6%. $Al_2O_3$ ; 8.1%, CaO ; 7.76%, Ign. loss ; 6.8%, MgO ; 0.23%, $K_2O$ ; 0.72%, $Na_2O$ ; 0.41%, $Fe_2O_3$ ; 0.32%. 5. The threshold friction velocity equation for the diameter class of the dune sands was $y=4.191x^{0.221}$. 6. The amount of floating salt was maximum at the point of 65m away from beach line, dropped abruptly at 135m and remained almost same on its way to the inland. The equation of the amount of floating salt was $y=28.181{\times}(-0.369^x)$. 7. The amount of extracted salt(33%) in seawater in summer was the same as the one of the nearest seawater of Korea.

• Journal of Nutrition and Health
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• v.43 no.2
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• pp.114-122
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• 2010

Se and Fe are trace minerals acting as antioxidant scavenging free radicals. Iron deficiency is the most frequently reported nutritional deficiency in females. Body iron status are known to be dependent not only upon dietary iron intake, but also upon micro-mineral nutrition and obesity. Antioxidants such as selenium are reported to play an important role on the regulation of erythropoiesis by protecting RBC membrane from antioxidative damage. In this study, iron status in young females and its relationships with selenium status and physique were examined. Serum selenium and iron concentrations were measured by HANARO research reactor using neutron activation analysis method (NAA-method). The proportion with iron deficiency and anemia were 27.1% and 8.6%, respectively in young females, but the proportion with iron deficient anemia was 1.4%. The mean serum selenium level was $12.0\;{\mu}g/dL$ and in normal range in the young women. The study participants were tertiled according to BMI and serum selenium levels. Serum ferritin and iron levels inclined with increasing BMI tertiles. Serum iron and RBC count were higher in middle selenium group than low selenium group. Individuals had significantly lower hematocrit level in the lowest tertile for their serum selenium levels compared with the highest tertile. The serum ferritin level was predicted 25% by BMI and RBC count 26.2% by the serum selenium level and body fat%. In conclusion, this study shows that body iron status in young adult females are influenced by obesity and body selenium status.

• Korean Journal of Human Ecology
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• v.3 no.2
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• pp.77-89
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• 2000

In this study, to activate the industrialization and to improve the quality of Toha-jeot by shortening the fermentation period, we investigated the changes in the nutritional components of Toha-jeot. salt-fermented Toha shrimp( Caridina denticulata denticulata $D_{E}$ $H_{AAN}$) which was salted with a low-salt group and high-salt group during fermentation. In this experiment. there are four groups of Toha-jeot which were manufactured with 15% ratio of common salt: the first group containing 2% wheat bran (w2%-L). the second high-salt group containing 2% wheat bran( w2%-H) , the third low-salt group containing 4% wheat bran (w4%-L) and the last high-salt group containing 4% wheat bran(w4%-H). These four groups were refrigerated at 4${\pm}$1$^{\circ}C$ and then taken out for analysis at three month intervals during 9 month. Among the free amino acid contents in Toha-jeot, 22 kinds were detected. 6 month after the fermentation when the quantity of the amino acid contents in Toha-jeot is highest, ornitine, glutamic acid, leucine. alanine. lysine and valine occupy the majority, in the order of abundance. In cases of nucleotides. 6 month after the fermentation. from the groups w2%-L, w2%-H and w4%-L, inosine and IMP were not detected. and hypoxanthine, AMP, ADP were detected but 9 month after the fermentation ADP was not detected. The main constituents of fatty acid were as follows : (a) from w2%-L, w2%-H, 6 month after the fermentation. $C16:0$, $C12:0$, $C18:1$, $C18:3$, and $C16:1$. (b) from w4%-L. 6 month after the fermentation, $C18:3$, $C16:0$, $C12:0$ and $C18:1$. (c) from W4%-H, $C16:0$, $C12:0$, $C18:3$ and $C18:1$. In case of mineral contents. Na, Ca. K. Mg, Fe. Zn, Mn and Cu were detected according to the magnitude of the quantity. From the group w4%-H, high quantity of Na was detected during the total fermentation period. In case of color value, from the groups w2%. the values of L. a. b were highest after 6 month fermentation and were decreased after 9 month fermentation, while from groups w4%, the values of L, a, b were gradually decreased after 3 month fermentation.ion.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.574-582
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• 1992

Exo-xylanase encoded by the xylA gene of Bacillus stearothermoPhillus was produced from Escherichia coli ]M109 carrying a recombinant plasmid pMGL Synthesis of the enzyme was observed to be cell-associated, and about 94% of the enzyme synthesized was located in the cytoplasmic region. The maximum production was attained when the E. coli strain was grown at $37^{\circ}C$ for 8 hours on the medium containing 0.5% fructose, 1.0% tryptone, 1.0% sodium chloride, and 0.5% yeast extract. The exo-xylanase was purified to homogeneity using a combination of salting out with ammonium sulfate, DEAE-Sepharose CL-6B ion exchange chromatography, Sephadex G-IOO gel filtration, and Sephadex G-150 gel filtration. The' purified enzyme was most active at pH 6.0 and $45^{\circ}C$. $Ca^{2+}$ and $Co^{2+}$ activated the exo-xylanase activity by about 20% while $Ag^{2+}$, $Fe^{2+}$, $Mg^{2+}$ and $Zn^{2+}$ inhibited the enzyme activity by up to 60%. The $K_m$, value on p-nitrophenyl-$\beta$-D-xylanopyranoside was 2.75 mM. The enzyme had a pI value of 4.7. The estimated molecular weight of the native protein was 200,000 daL SDS-polyacrylamide gel electrophoresis analysis suggested that the native enzyme was a trimer composed of three identical 66,000 da!. polypeptides. The purified enzyme efficiently converted all the xylo-oligosaccharides tested to xylose. It was also confirmed that the enzyme split xylans in an exo-manner even though the degree of hydrolysis was fairly low. The xylanolytic enzyme was, therefore, classified to be one of the few bacterial exo-xylanases lacking transferase activity.

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.1
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• pp.9-16
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• 1978

In order to establish a better combination of nutrients of complex fertilizer for apple tree a boron-enriched complex fertilizer ($N-P_2O_5-K_2O-B_2O_5-MgO$: 10 10-0.2-2.0) was compared with various treatments using urea superphosphate, potash muriate, usual complex fertilizer (22-22-11) and borax in its effect on the various growth status such as total leaf weight per tree and shoot growth of dwarf Fuji (1 year old) and super type Starcreamson (3 year old) grown at comparatively poor soils. For Fuji grown on sandy red soils the boron-enriched complex fertilizer (BC) was best and followed by-usual complex fertilizer NPK only, NPK only+Boron, BC+high boron (17times) and no phosphorus in the order. For Starcreamson grown on heavy clayey soils CB+high boron and phosphorus was best and followed by BC, usual complex fertilizer, NPK only, BC+high boron, NPK+boron and no phosphorus in the order. Without compost in the poor heavy clayey soil the growth was worse with high boron and best with NPK+boron and followed by BC Growth was poor with high boron alone but better with phosphorus and high boron, and it was thought that boron was effective when it was distributed in soil with N.P.K. Fertilizer response of apple tree was well appeared on leaf length, new shoot length and total leaf weight per tree. Suitable formulation of a boron-enriched complex fertilizer for apple tree appeared as 10-20-10-0.6 ($N-P_2O_5-K_2O-B_2O_5$) for poor fields and fields with moderate fertility. Chemical analysis of leaves suggested Mg effect on the increase of leaf weight. Effect of Fe was similar to thatof of Mg.

• Korean journal of applied entomology
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• v.59 no.3
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• pp.265-275
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• 2020

In this study, we analyzed the nutritional ingredients of drone pupae (16^th to 20^th instar old) to evaluate the value of bee products and provide basic data for product diversification, and the extracts prepared using these pupae were tested for physiological activity. According to the analysis of the general ingredients of the freeze-dried powder of these bee pupae, the moisture, crude protein, crude fat, and crude ash was 1.69 ± 0.07%, 48.52 ± 0.20%, 23.41 ± 0.14%, and 4.05 ± 0.02%, respectively. Vitamin C and vitamin E were 14.92 ± 0.52 mg/100 g and 6.06 ± 0.11 mg α-TE/100 g, respectively. Regarding minerals, the highest content of K (1349.13 ± 34.57 mg/100 g) and P (1323.55 ± 43.85 mg/100 g) was observed and Ca and Fe were 55.43 ± 1.51 mg/100 g and 5.49 ± 0.19 mg/100 g, respectively. The fatty acids of the water extracted freeze-dried pupae powder accounted for approximately 59.62 of saturated fatty acids and 40.38 of unsaturated fatty acids, and high-quality fatty acids such as palmitic acid (C16:0) was 35.49 ± 0.08 and oleic acid (C18:1, n-9) was 35.91 ± 0.22 (g/100 g total fatty acids). The total amino acid content was 38.99 ± 2.63 g/100 g and the free amino acid was a total of 5129.04 mg/100 g, of which 1257.68 mg/100 g was proline and 759.12 mg/100 g glutamic acid. The DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity of the drone pupae extract showed values of 0.8 for distilled water extract, 3.2 for 50% EtOH extract, 6.4 for 70% EtOH extract, and approximately 90% for 32 ㎍/mL for 100% EtOH extract. These results suggest that the main compound contributing to the antioxidant activity is a polar compound, and it is highly likely to be a low-molecular protein or a free amino acid. In conclusion, the honey bee drone pupa is excellent as a food resource and can be utilized as a new functional material for food and functional food.