• Korean Journal of Materials Research
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• v.1 no.3
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• pp.168-174
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• 1991

Ti-silicide was deposited by sputtering the composite target($TiSi_{2.6}$) on single-Si wafers and oxide on them. The heat treatment temperatures by rapid thermal annealing(RTA) have been varied in the range of $600-850^{\circ}C$ for 20seconds. It was not until RTA temperature was $800^{\circ}C$ that a stable $TiSi_2$ was formed, and the value of resistivity of that phase was $27~29{\mu}{\Omega}-cm$, which seems a little higher than that formed by the reactive method. The result of x-ray diffraction peals showed that till $750^{\circ}C$, C49 $TiSi_2$ phase was dominant, but at $800^{\circ}C$, at last, the phase was transformed into a stable C54 $TiSi_2$ phase. And, the result of x-ray photoeletron spectroscopy(XPS) measurements showed that the composition ratio of Ti and Si was 2 1 in the case of specimens treated at $800^{\circ}C$, The surface roughness of $TiSi_2$, which was condidered a weak point, was improved to a superior value of $17{\pm}1nm$, therefore increasing the possibility of applying $TiSi_2$ to semiconductor devices.

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.27-42
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• 2005

In this study, dynamic deformation characteristics of sands under dry, saturated drained and undrained conditions were investigated at small to intermediate strains using the modified Stokoe-type torsional shear tests. The equipment was modified to saturate the specimen and to maintain the B-value above 0.99 during the test. On two types of sands, Geumgang sand from Korea and Toyoura sand from Japan, tests were carried out at various drainage conditions, void ratios, and effective confining pressures. Based on the test results, dynamic deformation characteristics, shear modulus (G) and damping ratio (D), and/or pore-water pressure were measured with strain amplitude and number of loading cycles. Variations of G and D at small ($\gamma_c<{10}^{-3}\%$) to medium (${10}^{-3}\%<\gamma_c<{10}^{-1}\%$) strains were measured under various drainage conditions, and test results were intensively compared considering drainage conditions.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.571-579
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• 2016

RS-LMC (Rapid Setting Latex Modified Concrete) has been widely used as repair material for bridge deck overlay or rehabilitation, because the overlaid pavement could be opened to the traffic after 3 hours of curing. Although the field performance of RS-LMC generally indicates that it has an excellent bonding to the substrate and shows a long term performance, the crack by vibration of vehicles have been happened on the overlay of bridges in technical reports. In this study, experimental research was carried out to evaluate the vibration properties of RS-LMC overlays by using P.S.T (Pavement Shaking Table). Total 12 specimens were tested and the variables are Latex-cement ratio (L/C) and amplitude of vibration. The result shows that the number of cracks and the total length of cracks are reduced as the increase of Latex-cement ratio (L/C) until 15%. And the crack occurs at a very small strain than the proposed values by Walter, D, G and design codes.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.82-95
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• 1989

This study was carried out for the stability analysis of earth dam by the variation of compaction density. The test samples were taken from five kinds of soil used for banking material and the degree of compaction for this samples were chosen 100, 95, 90, 85, and 80 percent. The stability problems were analysed by the settlement and camber( extra banking) of dam, strength parameter and dam slope, and coefficient of permeability and seapage flow through dam body. The results of the stability analysis of earth dam are as follows. 1. The more the fine particle increases and lower the compaction degree becomes, the lower the preconsolidation load becomes but the compression index becomes higher. 2. Sixty to eighty percent of settlement of dam occurs during the construction period and the settlement ratio after completion of dam is inversly proportional to the degree of compaction. 3. The camber of dam has heigher value in condition that it has more fine particle(N) and heigher dam height(H) with the relation of H= e(aN-bH-e). 4. The cohesion(C) decreases in proportion to compaction degree(D) and fine particle(N) with the relation of C= aD+ bN-c, but the internal friction angle is almost constant regardless of change of degree of compaction. 5. In fine soil, strength parameter from triaxial compression test is smaller than that from direct shear test but, they are almost same in coarse soil regardless of the test method. 6. The safety factor of the dam slope generally decreases in proportion to cohesion and degree of compaction but, in case of coarse soil, it is less related to the degree of compaction and is mainly afected by internal friction angle. 7. Soil permeability(K) decreases by the increases of the degree of compaction and fine particle with relation of K=e(a-bl)-cN) 8. The more compaction thickness is, the less vertical permeability (Kv) is but the more h6rzontal permeability (KH) is, and ratio of Kv versus KH is largest in range from 85 to 90 percent of degree of corn paction. 9. With the compaction more than 85 percent and coefficient of permeability less than ${\alpha}$X 10-$^3$cm/sec, the earth dam is generally safe from the piping action.

• Journal of Nutrition and Health
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• v.40 no.2
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• pp.182-190
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• 2007

The purpose of this study is to evaluate dietary quality of Korea Antarctic expedition by menu analysis. Basic menu pattern, intake of dish and dish group, DDS (dietary diversity score), daily nutrients supply, and NAR (nutrient adequacy ratio) & MAR (mean adequacy ratio) were analyzed using 1 year menu list for the 10th Korea Antarctic expedition. Most frequently served basic menu patterns were ${\ulcorner}$Rice + Soup + 2 Side dish + Kimchi (53.5%)${\lrcorner}$ and ${\ulcorner}$Rice + Stew + 2 Side dish + Kimchi (13.4%)${\lrcorner}$. In the analysis of dish group, excluding Rice and Kimchi, ${\ulcorner}$Grilled foods${\lrcorner}$ and ${\ulcorner}$Pan-fried foods${\lrcorner}$ were served more than 25% per month. Most frequently served dishes were "pan-fried rolled egg", "grilled seaweed", "kimchi soup", "fruits cocktail, canned" and "salt-fermented squid". The kinds of served dishes were very restrictive. The average score of DDS showed 2.88 for summer and 2.97 for winter. Dairy group was almost not served. Fruit & Vegetable groups were also served a little as canned product. The energy ratio of Carbohydrate : Fat : Protein was 56.5 : 23.9 : 19.2, and 56.9 : 24.5 : 18.3, for summer and winter, respectively. Both seasons had higher ratio of carbohydrate and lower ratio of fat compared to the recommended ratio (44 : 40 : 16) in polar area. Ca : P ratio was very poor, 0.40 in both seasons. NAR scores of Ca, vitamin A, vitamin $B_2$ and vitamin C were also very low, ranged from 0.6 to 0.7. Consequently, a well-planned menu supplying adequate amount of dairy, fruit and vegetable is necessarily required including Ca, vitamin D, vitamin A, vitamin $B_2$ and vitamin C intake, and some nutritionally well-educated members are urgently needed to join in the expedition.

• Biomolecules & Therapeutics
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• v.18 no.4
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• pp.454-462
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• 2010

The present study investigated the neuroprotective effect of Carpinus tschonoskii MAX and its intracellular protective mechanism on 6-hydroxydopamine (6-OHDA)-induced oxidative damage in PC12 cells. We found that pretreatment of PC12 cells with C. tschonoskii extract significantly inhibited the cell death induced by 6-OHDA in a dose dependent manner. C. tschonoskii extract decreased 6-OHDA-induced apoptotic events such as chromatin condensation, DNA fragmentation, the decrease of Bcl-2/Bax ratio, caspase-3 activation and PARP cleavage. C. tschonoskii extract also reduced generation of 6-OHDA-induced reactive oxygen species and nitric oxide. Furthermore, C. tschonoskii extract up-regulated the myocyte enhancer factor 2 D (MEF2D), a critical transcription factor for neuronal survival, and Akt activity, whereas it inhibited the activity of ERK1/2 and JNK. The results suggest that C. tschonoskii extract decreases 6-OHDA-induced oxidative stress and could prevent PC12 cell apoptosis induced by 6-OHDA via the up-regulation of MEF2D and Akt activity, and thus may have application in developing therapeutic agents for Parkinson's disease.

• Herbal Formula Science
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• v.17 no.2
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• pp.133-142
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• 2009

Objective : Recently, obesity has increased at an alarming rate and is now a worldwide health problem. Natural dietary supplement, $CharmSlim^{(R)}$(C), is mixed pills, which consists of beans, black sesames, kelps, onions, adlay seeds, anchovies, pyogo mushrooms, green tea. Our study was performed to determine the weight-loss effects of natural dietary supplement, based on natural ingredients, in mice fed high-fat diet with an abundance of carbohydrates. Methods : Four groups of male ICR mice were fed different diets during 6 weeks: normal diet(NOR), high-fat (15%, w/w) diet(HF), high-fat supplemented with natural dietary supplement powdered 5%(C5) and 10%(C10) groups. We measured the changes of food intake, body weight and adipose tissues weights. Also we examined levels of lipid profiles in serum. Results : Body weight, liver weight and food efficiency ratio were significantly higher in the HF group than in NOR group. After 6 weeks of treatment, body weight, liver weight and adipose tissues weights (epididymal, perinephric, visceral and BAT) were significantly decreased in the C10 group when compared to the control HF group. The C10 group had markedly lower serum levels of total cholesterol and triglyceride when compared with HF group. Conclusion : These results demonstrate that this dietary supplement can suppress the increased lipid profiles, body weight and fat gains, thus could be considered as an effective adjunct in the treatment of obesity.

• Journal of the Korean Applied Science and Technology
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• v.16 no.2
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• pp.117-125
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• 1999

The alkylation benzene with 1-dodecene of Mordenite, Zeolite ${\beta}$ and Zeolite Y was studied in the stirring batch reactor. The kinds of zeolites were found to have influenced the reaction conversion and distribution of phenyldodecane isomer in the product. Compared to the alkylation conducted over Zeolite Y and Zeolite ${\beta}$, the alkylation over Mordenite exhibited higher distribution of 2-phenyldodecane and the alkylation conducted over Zeolite Y and Mordenite, the alkylation over Zeolite ${\beta}$ exhibited higher distribution of heavy alkylate which formed through oligomerization reaction readily deactivated the Lewis acid sites. A special feature of the effect of the benzene to 1-dodecene ratio the reaction conversion and selectivity of phenyldodecane isomer was found. At alkylation of benzene with 1-dodecene over Zeolite ${\beta}$, when the catalyst content in the system was high, the reaction will reach the optimal conversion at the higher B/D. When the benzene to 1-dodecene ratio was high, the selectivity of phenyldodecane isomer is high. It was also found that at the similar reaction conversion there was the same product distribution regardless of D/C ratio.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.916-923
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• 2005

In this study, to observe aging effect of undrained shear behavior for Nak-Dong River sand, undrained static and cyclic triaxial tests were performed with changing relative density ($D_r$), consolidation stress ratio($K_c$) and consolidation time. As a result of the test, the modulus of elasticity to all samples estimated within elastic zone by the micro strain of about 0.05% in case of static shear behavior increased with the lapse of consolidation time significantly, so aging effect was shown largely. Also strength of phase transformation point(S_{PT}$) and strength of critical stress ratio point($S_{CSR}$) increased with the lapse of consolidation time. Undrained cyclic shear strength($R_f$) obtained from the failure strain 5% increased in proportion to relative density($D_r$) and initial static shear stress($q_{st}$), $R_f$ of consolidated sample for 1,000 minutes increased about 10.6% compared to that for 10 minutes at the loose sand, and $R_f$ increased about 7.0% at the medium sand. In situ application range of $R_f$ to the magnitude of earthquake for Nak-Dong River sand was proposed by using a increasing rate of $R_f$ as being aging effect shown from this test result.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.9 s.252
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• pp.873-881
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• 2006

The present study investigates the pressure drop characteristics in rotating two-pass ducts. The duct has an aspect ratio (W/H) of 0.5 and a hydraulic diameter $(D_h)$ of 26.67mm. Rib turbulators are attached crossly in the four different arrangements on the leading and trailing surfaces of the test ducts. The ribs have a rectangular cross section of $2mm(e){\times}3mm(w)$ and an attack angle of $70^{\circ}C$. The pitch-to-rib height ratio (pie) is 7.5, and the rib height-to-hydraulic diameter ratio $(e/D_h)$ is 0.075. The results show that the highest pressure drop among each region appears in the turning region for the stationary case, but appears in the upstream region of the second pass for the rotating case. Effects of cross rib arrangements are almost the same in the first pass for the stationary and rotating cases. In the second pass, however, heat transfer and pressure drop are high for the cases with cross NN or PP type ribs in the stationary ducts. In the rotating ducts, they are high for the cases with cross NP or PP type ribs.