• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.15-24
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• 2021

In Korea, which is mostly mountainous, the proportion of tunnel and underground space development are increasing. Although the ground is reinforced by applying the ground improvement method during underground space development, accidents still occur frequently in Korea. In the grouting method, a representative ground reinforcement method, the effect was judged by comparing the total amount of injection material with the amount of injection material used during the actual grouting construction. However, it is difficult to determine whether the ground reinforcement is properly performed during construction or within the target ground. In order to solve this problem, it is necessary to study a new method for quality control during or after construction by measuring electrical resistivity after performing grouting by mixing carbon fiber, which is a conductive material, and microcement, which is a grout material. In this study, as a basic study, a cement specimen mix ed with 0%, 3%, 5%, 7% of carbon fiber was prepared to evaluate the performance of the grout material mixed with carbon fiber, which is a conductive material. The prepared specimens were wet curing for 3 days, 7 days, and 28 days under 99% humidity, and then compression wave velocity and shear wave velocity were measured. As a result of the compression wave velocity and shear wave velocity measurement, it showed a tendency to increase with the increase in the compounding ratio of carbon fibers and the number of days of age, and it was confirmed that the elastic modulus and shear modulus, which are the stiffness of the material, also increased.

• Sijohaknonchong
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• v.23
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• pp.161-188
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• 2005

The purpose of this study was to delve into the morphological types of Sijo in an effort to determine the morphological structure of Sasul-sijo, and it's also attempted to present standard about how to discriminate Pyong-si, Eos-sijo and Sasul-sijo from one another from a morphological standpoint. It's suggested that Si with tee Jangs, six verses and 12 stanzas or more, with three Jangs, seven verses and 14 stanzas or more, and with three Jangs, eight verses and 16 stanzas or more should respectively be called Pyong-sijo, Eos-sijo and Sasul-sijo. After what Sijo was and what's not were discussed, how to distinguish Eos-sijo from Sasul-sijo was described, and finally, the structure of Sasul-sijo was presented. As for Sijo and non-Sijo, the types of works that consisted of tee Jangs, like Sijo, yet didn't suit its framework and Yuljo and were written in Chinese characters were regarded as non-Sijo. Concerning discrimination between Eos-si and Sasul-sijo, the type of Sijo that included one more or higher number of verse(s) and two more or higher number of stanzas in one of three Jangs was defined as Eos-sijo, and the type of Sijo that involved two more or higher number of verses and four more or higher number of stanzas in one of three Jangs was called Sasul-sijo. In other words, Eos-sijo contained one more verse in one of tee Jangs, and Sasul-sijo included one more Jang in one tee Jangs. The sort of Sijo that contained one more Jang in one of three Jangs could be viewed as Sasul-sijo. Regarding the structure of Sasul-si, there should be three Jangs, eight verses and 16 stanzas in one piece of Sasul-sijo. Any type of Sijo that contained two more or higher number of verses and four more or higher number of stanzas could be called Sasul-sijo. Such an addition of verse and stanza could done in various ways. The examples were (1) adding stanzas the first Jang, 2) adding stanzas to the second Jang, (3) adding stanzas to the final Jang, (4) adding stanzas to both the first and Second Jangs, (5) adding stanzas to th the second and final Jangs, and (6) adding stanzas to all the first, second and third Jangs at the same time. Besides, there was an extremely broad gap between the numbers of verse and stanza in Sasul-sijo, which ranged from a low of eight stanzas to a high of 87 ones in one of three Jangs.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.4
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• pp.11-19
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• 2018

This study was conducted to develop the manufacturing method of biochar using pruned stems of pear tree and its application effect on the crop growth and soil physico-chemical properties. In this study, biochar derived from pruned stems of pear tree at heating temperature of $300^{\circ}C$, $500^{\circ}C$ and $700^{\circ}C$ in heating times of 2, 3 and 4 hours, were tested in the changes of their chemical properties during biochar processing. The pH, Exch. K, Exch. Mg and cation exchange capacity (CEC) increased as the pyrolysis temperature increased during the production of biochar, and the change of these properties rapidly occurred at $500^{\circ}C$. However, as the pyrolysis temperature increased, ash content increased and total carbon (T-C), yield decreased. And the change of the properties in response to the heating time was not shown. It was thought that it would be desirable to set the production conditions of biochar at $500^{\circ}C$ for 2 hours in consideration of the change of chemical properties and the ash content and yield. And also, were conducted the experiments to establish manufacturing method of farm-made biochar using drum biochar manufacturing machine and investigate the application effects of biochar on the cultivation of chinese cabbage and tomato. Application of biochar derived from pruned stems of pear tree could enhance pH, organic matter (OM), total carbon (T-C) of soil. On the other hand, soil electrical conductivity (EC), NO3-N were lowered compared to the control which has no application. The bulk density, porosity and aggregate formation of soil were improved by biochar application. The fresh matter yields of chinese cabbage and tomato were significantly increased in proportion to the application rate of biochar. This study demonstrated the effect of the biochar derived from agricultural byproduct to be as a low cost potential soil ameliorant by physico-chemical properties in eco-friendly greenhouse cultivation.

• Journal of the Korean Institute of Landscape Architecture
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• v.14 no.2
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• pp.7-16
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• 1986

This study was carried out to investigate the effects of such erosion control measures as sowing, planting and small earth structures on the soil and vegetation. In order to study the changes in soil and vegetation, 36 plots were surveyed from 1981 to 1982 in the large erosion control area which is restored last 20 years. The factors which were measured included vegetation coverage, tree growth, number of species, soil depth, soil consistancy, and Chemical properties of soil. The results were as follows; 1) Maximum coverage of the overstory and understory was attained 7 years after the initiation of erosion control. So the overstory need to be tended and pruned. 2) Diversity of species increased until age 6 after which it began to decrease. 3) In order of tree growth, black locust was the fastest, followed by siberian alder and pitch pine. The initial growth of black locust, though the best among the 3 tree stop., decreased rapidly year by year. At the same time, siberian alder and pitch pine grew well until 12 and 6 years after the initiation of erosion control respectively. 4) Fifty percent of the initially planted trees died within 8 yeard. The mortality of siberian alder occurred until the 20th year while the mortality of pitch pine stopped after 10 years. Thereafter 500 trees per hectare were maintained. 5) The soil depth in A and B horision increased by 2cm annually during 20 years. The soil consistency also decreased rapidly until 7th year. The physical soil properties of the rehabilitated areas were improved after the 14th year. 6) The soil pH tend to decrease from 5.3 during the first year to 5.1 during the twentieth year. 7) The organic matter and nitrogen content in the soil were increased by fertilization but after 20 years these nutrients are still deficient for normal tree growth. 8) The phosphorous content in the soil was high in the first year but the longer the period after the initiation of erosion control the lese the content of phosphorous. 9) The biomass of black locust was the highest and increased continuously. The biomass of siberian alder on the contrary decreased from the 15th year because the number of trees in this place was very low. The total biomass in the twentieth year after erosion control initiation was 105.7 ton per hectare.

• The Journal of Engineering Geology
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• v.29 no.1
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• pp.51-68
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• 2019

This study performs to evaluate adaptability of seashore filtering type seawater-intake which adapts dua1 filter well alternative for direct seawater-intake. This study varies filter condition of seashore free surface aquifer which is composed of sand layer then installs real size dual filter well and single filter well to evaluate water permeability and proper pumping amount according to filter condition. According to result of step aquifer test, it is analysed that 110.3% synergy effect of water permeability coefficient is happened compare to single filter since dual filter well has better improvement. dual filter has higher water permeability coefficient compare to same pumping amount, this means dual filter has more improved water permeability than single filter. According to analysis result of continuous aquifer test, it is evaluated that dual filter well (SD1200) has higher water permeability than single filter well (SS800) by analysis of water permeability coefficient using monitoring well and gauging well, it is also analysed dual filter has 110.7% synergy effect of water permeability coefficient. As a evaluation result of pumping amount according to analysis of water level dropping rate, it is analysed that dual filter well increased 122.8% pumping amount compare to single filter well when water level dropping is 2.0 m. As a result of calculating proper pumping amount using water level dropping rate, it is analysed that dual filter well shows 136.0% higher pumping amount compare to single filter well. It is evaluated that proper pumping amount has 122.8~160% improvement compare to single filter, pumping amount improvement rate is 139.6% compare to averaged single filter. In other words, about 40% water intake efficiency can be improved by just installation of dual filter compare to normal well. Proper pumping amount of dual filter well using inflection point is 2843.3 L/min and it is evaluated that daily seawater intake amount is about $4,100m^3/day$ (${\fallingdotseq}4094.3m^3/day$) in one hole of dual filter well. Since it is possible to intake plenty of water in one hole, higher adaptability is anticipated. In case of intaking seawater using dual filter well, no worries regarding damages on facilities caused by natural disaster such as severe weather or typhoon, improvement of pollution is anticipated due to seashore sand layer acts like filter. Therefore, It can be alternative of environmental issue for existing seawater intake technique, can save maintenance expenses related to installation fee or damages and has excellent adaptability in economic aspect. The result of this study will be utilized as a basic data of site demonstration test for adaptation of riverside filtered water of upcoming dual filter well and this study is also anticipated to present standard of well design and construction related to riverside filter and seashore filter technique.

• Journal of Animal Science and Technology
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• v.54 no.1
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• pp.1-8
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• 2012

This study aimed to investigate the single nucleotide polymorphisms (SNPs) of the porcine MC4R gene and validate the effect of the MC4R genotype for marker assisted selection (MAS). Six amplicons were produced to analyze the entire base sequences of the porcine MC4R gene and six SNPs were detected (c.-780C>G, c.-135C>T, c.175C>T-Leu59Leu, c.707A>G-Arg236His, c.892A>G-Asp298Asn, and c.*430A>T). Linkage disequilibrium (LD) of the six SNPs was analyzed by performing haploid analysis. There was a perfect linkage disequilibrium in c.-780C>G, c.-135C>T, c.175C>T-Leu59Leu, c.707A>G-Arg236His, and c.*430A>T. Only the c.892A>G (Asp298Asn) SNP showed a very low LD with an $r^2$ value of 0.028 and the D' value of 0.348. As a result, the two SNPs-c.707A>G (Arg236His) and c.892A>G (Asp298Asn)-were selected to extract the genotype frequencies from the 5 pig breeds by using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotype analysis method. The SNP frequency of c.707A>G (Arg236His) indicated the presence of the A (His) allele only in Yorkshire, while the G allele was fixed in the KNP, Landrace, Berkshire, and Duroc. Association analysis was carried out in 484 pigs with the c.707A>G (Arg236His) SNP and the meat quality traits of four different pig cross populations: a significant association was noted in crude fat, sirloin moisture, meat color, and the degree of red and yellow coloration. The frequency of the c.892A>G(Asp298Asn) SNP genotype varied among the breeds; while Duroc showed the highest frequency of the A (Asn) allele, KNP showed the highest frequency of the G (Asp) allele. Association analysis was carried out in 1126 pigs with the c.892A>G (Asp298Asn) SNP and the meat quality traits of four pig populations: a highly significant linkage was noted in the back-fat thickness (P<0.002). It was found that the back-fat thickness was higher in individuals with the AA genotype than in those with the AG or GG genotype. Thus, in this study, we verified that the c.892A>G (Asp298Asn) SNP in the pig MC4R gene has a sufficient effect as a gene marker for MAS in Korean pork industry.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.404-412
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• 2012

The main object of this study is to render a better dental education to mental disabilities, teachers, and their parents. By providing a better dental education to them, mental disabilities would understand the importance of their oral hygiene. The study was held in Seoul at two different locations, named H and E mental welfare facilities. Ninety Three mental disabilities were studied by observing their oral behavior, simple oral hygiene index and plaque index prior and post to dental education. At the end of education, following result were gathered from two mental facilities. First, the level of oral behavior in Class 1,2, and 3 mental disabilities were observed prior and post to the dental education. Overall, there was no significant difference among Class 1 mental disabilities with the dental education. Second, in simple oral hygiene index, the severity of mental illness has affected on their oral behavior (F=6.322, p<.001). Third, in simple oral hygiene index, the frequency of dental education, regardless of severity of mental illness has affected on their oral hygiene (F=5.961, p<.01). Fourth, the plaque index also illustrated that the frequency of dental education, regardless of severity of dental illness has affected on their oral hygiene (F=5.126, p<.05). Finally, the general characteristics of mental disabilities according to changes in oral health awareness to gender, age, disability type, educational level do not statistically significant in all variables. Their simple oral hygiene index and plaque index advanced, although after a while they started to lose focus, which brought back their old habits. Nevertheless, in conclusion I believe that helping mental disabilities more frequently to constant reminder, will not only keep them entertained, but help them realize how important oral hygiene practice is, hopefully increasing and benefiting those with mental disabilities for future reference.

• Journal of Animal Science and Technology
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• v.50 no.5
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• pp.621-632
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• 2008

Genetic polymorphisms was investigated at five single nucleotide polymorphisms(SNP) sites in four porcine genes(ADCYAP1R1, FABP3, MC4R, and MYL2) and analyzed their statistical association with growth traits in F2 reciprocal-crossbred population between Landrace and Jeju native black pig(JNP). All populations, JNP, Landrace and their F2 were polymorphic for all five SNP loci tested, however, the homozygote T/T of FABP3 g.-158T>C and the homozygote G/G of ADCYAP1R1 intron 2 337A>G were not found in JNP and Landrace, respectively. The genotypes of ADCYAP1R1 were significantly associated with body weights(BW) at 3 weeks and at 20 weeks(P<0.05), respectivley, those of FABP3 g.-135delT were associated with late average daily gain(LADG) (P<0.01), and those of FABP3 g.-158T>G were associated with body weights during late growth period such as, BW20 and LADG(P<0.01). Those of MC4R were also significantly associated with BW10 suggesting by the difference of early average daily gain(EADG) (P<0.05), and with LADG(P<0.01). The body length of F2 animals was affected by the genotypes of ADCYAP1R1, MC4R, and MYL2(P<0.05), respectively. Among these, MC4R A/A homozygotes showed over 3 cm longer in body length than those of other genotypes. As the useful basic information, these results suggested that SNP markers showing statistical association with growth traits and the results help to select the sires of JNP for improving the productivity in JNP-related crossbreeding system in pig industry and also to construct the molecular breeding system for breed improvement of JNP itself.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.21-36
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• 2005

Although the main geology of Korea consists of granite and gneiss, it Is not uncommon to encounter anisotropy Phenomena in crosshole radar tomography even when the basement is crystalline rock. To solve the anisotropy Problem, we have developed and continuously upgraded an anisotropic inversion algorithm assuming a heterogeneous elliptic anisotropy to reconstruct three kinds of tomograms: tomograms of maximum and minimum velocities, and of the direction of the symmetry axis. In this paper, we discuss the developed algorithm and introduce some case histories on the application of anisotropic radar tomography in Korea. The first two case histories were conducted for the construction of infrastructure, and their main objective was to locate cavities in limestone. The last two were performed In a granite and gneiss area. The anisotropy in the granite area was caused by fine fissures aligned in the same direction, while that in the gneiss and limestone area by the alignment of the constituent minerals. Through these case histories we showed that the anisotropic characteristic itself gives us additional important information for understanding the internal status of basement rock. In particular, the anisotropy ratio defined by the normalized difference between maximum and minimum velocities as well as the direction of maximum velocity are helpful to interpret the borehole radar tomogram.

• Journal of the Korean Geosynthetics Society
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• v.17 no.2
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• pp.41-49
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• 2018

The purpose of this study is to fabricate a full scale road embankment using lightweight air foamed soil as a soil material on soft ground and to investigate its material characteristics and behavior in order to promote dredged soil utilization and minimize ground improvement. As a result of the laboratory test of the onsite mixed samples, the total unit weight of the specimens decreased almost linearly until curing 28 days. In particular, the total unit weight after 28 days of curing was reduced to about 81% of the slurry state before curing, which will be useful in the formulation of similar native soil materials in the future. The unconfined compressive strength began to decrease with the 14th day of curing as shown in the previous study. When the cement content is increased, the strength decreases sharply at a small strain change after the occurrence of the maximum compressive strength, and the maximum strength is exhibited in a range of a smaller axial strain than normal range. The settlement at the surface layer of the ground due to the lightweight embankment was about 1 / 2.75 of the soil embankment and was in agreement with the unit weight ratio (1 / 2.7) of the embankment materials. This indicates the cause and effect of the settlement due to the difference in self weight of the embankments. Also, the difference in settlement between soil and lightweight embankment increased with increasing depth. This shows that the difference in the point at which the settlement is terminated is clear. The ground horizontal displacement under the lightweight embankment was about 15~20% smaller than that of the soil embankment and the depth of occurrence was also 4.5~5.0m shallower in the lightweight embankment.