• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.69-76
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• 2007

As amount of waste matter rapidly increases with fast growth of cities and industry, how to dispose them has arisen as an important problem. Current policy of the government on disposal of waste is repressing generation of waste itself and in case of already generated waste, resource cycle waste management system that recycles waste after proper environmental process is getting established. Therefore recycling of waste and industrial by-products is rising hugely. One of largely wasted matters is waste gypsum, which was categorized as designated waste but changed to general since 1994. Due to disposal cost and lack of impurities removal technology, recycling of it was quite low. However, as impurities removal technology using semi-dried desulfurization process is developed lately, study on recycling of waste gypsum is going on lively. This study examines possibility of utilizing waste gypsum as alternative for concrete cement and analyzed attributes of waste gypsum before and after ball mill process to find out proper alternation ratio, and conducted strength and property tests on concrete subject whose percentage of cement use is substituted with 0, 5.0, 7.5, 10.0 and 12.5% of waste gypsum.

• Journal of Korean Home Economics Education Association
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• v.20 no.2
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• pp.31-46
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• 2008

The purpose of this study is to analyze the contents of elderly housing in the unit "Family Life & Housing" in Technology & Home Economics 9th grade textbooks. The results of this study are as follows: First, the contents, illustrations, pictures, floor-plans, graphs and tables in current unit "Family Life & Housing" varied widely among textbooks and some didn't even contain these informations. Illustrations and pictures which are suit to the content and which contain positive image of space and living should be chosen. Second, most of the contents about elderly housing were concentrated on the life cycle, three-generation housing and universal design, discussed in chapter 'utility of living space.' The unification of overlapped contents and description which don't have stereotype about elderly housing are needed. Not only the interior environment but also the exterior environment of the elders and life-support service for them should be included in the contents. Contents that reflect the change of future population composition and the ratio of three-generation household are required. The elderly housing floor plan needs to be diversified in quantity such as ones which reflect the Korean characteristics or ones which enable person an independent life.

• Korean Chemical Engineering Research
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• v.51 no.5
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• pp.550-555
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• 2013

A hydrogel electrolyte consisting of potassium poly(acrylate) (PAAK) (3 wt%) in 6 M KOH aqueous solution is coated on poly(acrylonitrile) nonwoven separator to examine high-rate characteristics of activated carbon supercapacitor adopting the separator. The hydrogel is homogeneously coated on the surface pores of the nonwoven separator. The electrolyte uptake of the PAAK hydrogel maintains for 24 days higher than 230% and the coated separator shows slightly lower ionic conductivity ($2.9{\times}10^{-2}Scm^{-1}$) than that ($3.6{\times}10^{-2}Scm^{-1}$) of using 6 M KOH only. The activated carbon supercapacitor adopting the coated separator shows a specific capacitance higher than $27Fg^{-1}$ at $1000mVs^{-1}$ and a retention ratio higher than 97% after the 1000th cycle. This is due to strong interfacial contact of coated hydrogel electrolyte between the activated carbon electrode and the nonwoven separator.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.93-102
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• 1998

Normal and abnormal follicular growth and steroidogenesis depend on gonadotropins as well as intraovarian peptides, which may mediate or potentiate gonadotropin action. Inhibin also affect follicular development and steroidogenesis and may play a role in dominant follicle selection and follicular atresia. Therefore, we studied the differences of serum inhibin, gonadotropin and androgen levels in the women with only the ultrasound findings and no disorder, and polycystic ovary (PCO) with ovulatory disturbance. We prospectively analysed forty-three women with PCO. The diagnosis of PCO was based on typical appearance of the ovaries on TVS. Twelve women with regular menstrual cycle and normal ovarian morphology were selected as control. Basal levels of inhibin, luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol $(E_2)$, testosterone (T), androstenedione (ADD), dehydroepiandrosterone-sulfate (DS), prolactin and TSH in serum were determined. There were significant differences in basal LH levels and LH/FSH ratio between the control and the women with PCO. The basal levels of inhibin and $E_2$ in the oligo-amenorrheic PCO (N=34) were significantly higher than those in the control. There was higher negative correlation between the inhibin and T levels in the oligo-amenorrheic PCO, but, not in the regular cycling PCO. Also, there was higher positive correlation between the LH and T levels in the oligo-amenorrheic PCO, but not in the regular cycling PCO. These data presume that the initial event of PCO is elevated pituitary LH secretion. Elevated levels of LH may down-regulate LH receptors on granulosa cells and also cause hypertrophy of the thecal layer. High level of androgen secreted by the hypertrophied thecal layer may stimulate inhibin secretion from granulosa cells and can be converted to estrogen by extraovarian tissues and could serve to augment pituitary sensitivity to GnRH with a resultant secretion of more LH than FSH. Inhibin may inhibit FSH action on granulosa cell in the PCO follicle, impairing follicular development and dominant follicle selection resulted in ovulatory disturbance.

• Clinical and Experimental Reproductive Medicine
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• v.17 no.2
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• pp.173-184
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• 1990

At infertility clinic, department of Obstetrics and Gynegology, Kyung Hee Medical Hospital, 80 patients who underwent IVF-ET from January to July, 1989 were evaluated for the prediction of endogenous LH Surge and its effects on outcome of controlled ovarian hyperstimulation (COH) were compared among LH Surge group without hCG given (N=18), with hCG given (N=5), and no-LH Surge group with hCG given (N=57). LH Surge were occurred in 23(28.7%) out of 80 patients studied. Serum E2 levels on Day-1, Day 0, Day+1, were no significant different among three groups. When basal serum LH/FSH ratio is above 1.0, the possibility of endogenous LH Surge is much higher (56.3% in LH Surge group without hCG given). Serum P4 levels on Day 0 were significantly increased in LH Surge group without hCG given. Cycles which serum P4 level is higher than l.0ng/ml were 70.6% of LH Surge group without hCG given. But there was no significant interrelationship between endogenous LH Surge and serum P4 rising rate as an efficient predictor of the occurrence of endogenous LH Surge in COH for IVF. There was no significant differences in number of follicles, follicular size on Day-1, Day 0, Day+1, and number of oocyte collected per cycle. The oocyte fertilization rate of No-LH surge group with hCG given was significantly higher than LH Surge group without hCG given. There was no significant difference in oocyte cleavage rate among three groups.

• The Journal of the Petrological Society of Korea
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• v.5 no.2
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• pp.142-160
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• 1996

Petrological and geochemical characteristics of A-type granite were studied from the Namsan and Tohamsan granites in the vicinity of Kyeongju city, southeastern Korea. The Namsan granite consists of hypersolvus alkali-feldspar granite in the northern part and subsolvus alkali-feldspar to biotite granite in the southern part. This hypersolvus granite usually has miarolitic cavities and is characteristically composed of quartz, single homogeneous one-feldspar (alkali feldspar) forming tabular microperthite crystals, or micrographic intergrowth with quartz, and interstitial biotite (Fe-rich annite), alkali amphibole (riebeckitic arfvedsonite) and fluorite. Petrographic and petrochemical characteristics indicate that the hypersolvus granite and subsolvus granite from the Namsan belogn to the A-type and I-type granitoid, respectively. The A-type granite is petrochemically distinguished from the I-type Bulgugsa granites of Late Cretaceous in South Korea, by higher abundance of $SiO_2$, $Na_2O$, $Na_2O+K_2O$, large highly charged cations such as Rb, Nb, Y, Zr, Ga, Th, Ce. U the REEs and Ga/Al ratio, and lower abundance of $TiO_2$, $Al_2O_3$, CaO, $P_2O_5$, MnO, MgO, Ba, Sr, Eu. The total abundance of REEs is 293 ppm to 466 ppm, showing extensively fractionated granitic compositon, and REEs/chondrite normalized pattern shows flat form with strong Eu '-' anomaly ($Eu/Eu^{\ast}$=0.03-0.05). A-type granite from the Namsan area is thought to have been generated late in the magmatic/orogenic cycle after the production of I-type granite and by direct, high-temperature partial melting of melt-depleted, relatively dry tonalitic/granulitic lower crustal material with underplating by mantle-derived basaltic magmas associated with subduction.

• The Korean Journal of Mycology
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• v.22 no.1
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• pp.107-116
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• 1994

Interorder somatic hybrids were obtained by protoplast fusion between Pleurotus ostreatus in the order Agaricales and Elfvingia applanata in the order Aphyllophorales. The fusants were classified into stable heterokaryons and spontaneously segregated heterokaryons. Hyphae of all fusion products except two strains did not form clamp connections. Out of them, two clamped and three clampless fusants produced mature fruiting bodies by light-dark cycle on sawdust rice bran medium. All of these basidiocarps had clamp connections. Three fusants were analysed with the distribution of progenies and segregation of genetic characters by random spore analyses. The genetic markers were shown to segregate and recombine in the first generation of monospores isolated from basidiocarps. Phenotypes of a large number of auxotrophic progenies were not detected in the two clamped fusants. The aberration ratio of segregants indicated the gene interaction resulting from different genome structure between distantly related species. The polymerase chain reaction (PCR) was adopted for the detection of somatic hybrids nuclear DNA. Four fusants showed a positive results in three kinds of primers. The prominent reaction products are represented by new bands in primer # 87 and # 125. Out of four fusants, two somatic hybrids had non-parental mtDNA patterns when digested with EcoR1 and HindIII. Comparison of somatic hybrids, tissue culture isolates(TC) and multispore germination isolates(MS) were made using esterase isozyme analysis. It is apparent that somatic hybrids had a minor banding patterns which are quite different from those of parents.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.37-42
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• 2002

Artificial neural networks are efficient computing techniques that are widely used to solve complex problems in many fields. In this paper a liquefaction potential was estimated by using a back propagation neural network model applicated to cyclic triaxial test data, soil parameters and site investigation data. Training and testing of the network were based on a database of 43 cyclic triaxial test data from 00 sites. The neural networks are trained by modifying the weights of the neurons in response to the errors between the actual output values and the target output value. Training was done iteratively until the average sum squared errors over all the training patterns were minimized. This generally occurred after about 15,000 cycles of training. The accuracy from 72% to 98% was shown for the model equipped with two hidden layers and ten input variables. Important effective input variables have been identified as the NOC,$D_10$ and (N$_1$)$_60$. The study showed that the neural network model predicted a CSR(Cyclic shear stress Ratio) of silty-sand reasonably well. Analyzed results indicate that the neural-network model is more reliable than simplified method using N value of SPT.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.308-312
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• 2013

Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481 $m^2/g$) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using $LiMn_2O_4$, $LiCoO_2$ as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes ($LiPF_6$, $TEABF_4$) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using $LiMn_2O_4$/AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.4
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• pp.293-301
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• 2017

A Sub-kWe small-scale experimental test loop was manufactured to investigate characteristics of the supercritical carbon dioxide power cycle. A high-speed turbo-generator was also designed and manufactured. The designed rotational speed of this turbo-generator was 200,000 rpm. Because of the low expansion ratio through the turbine and low mass flowrate, the rotational speed of the turbo-generator was high. Therefore, it was difficult to select the rotating parts and design the turbine wheel, axial force balance and rotor dynamics in the lab-scale experimental test loop. Using only one channel of the nozzle, the partial admission method was adapted to reduce the rotational speed of the rotor. This was the world's first approach to the supercritical carbon dioxide turbo-generator. A cold-run test using nitrogen gas under an atmospheric condition was conducted to observe the effect of the partial admission nozzle on the rotor dynamics. The vibration level of the rotor was obtained using a gap sensor, and the results showed that the effect of the partial admission nozzle on the rotor dynamics was allowable.