• Biomedical Science Letters
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• v.2 no.1
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• pp.71-90
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• 1996

There is considerable current interest in the effect of regular vigorous exercise and in particular endurance-running as a possible measure in improving myocardial function. Some data indicate that the aging heart may actually suffer from vigorous endurance exercise. On the contrary appropriate exercise in aged animals improves myocardial function and aerobic energy metabolism. So far there is relatively little data to indicate that endurance exercise is in fact beneficial in improving myocardial function or damaging to heart of aged animals. The present investigation aimed to study the possible effect of a long range treadmill training program on the heart in aging rats. Male rats aged 3, 10, and 20 months were divided at random into a control (sedentary) and an exercise group. The training group was exercised for 5 days a week on an automated treadmill for 20minutes at 18m/min over a period of 5 months. The exercise regimen of our experiments did not cause any significant changes in the tissues and ultrastructural as com-pared with sedentary age-matched control. Tissues and ultrastructures of myocardial cells in trained group aged 8 months are intact and well organized as well as sedentary control group. Age associated tissue and ultrastructural changes of trained group aged 15 months included : an increase in transformed mitochondria, vacuoles, lysosomes, lipid droplets and early lipofuscin. But the trained heart did not show significant difference in tissue and ultrastructural properties from those of sedentary controls. Endurance-trained group aged 25 months showed significant qualitative tissue and ultrastructural difference as compared with age-matched controls. In addition to those found in 25 months control group, focal necrosis, myofibril fraying, hypercontraction band, seperation of intercalated discs, degenerating nucleus and infiltration of collagenous fiber into myocyte were noted in trained 25 months group. The stereological examination of the mi-crographs disclosed no significant difference in the myoflbril, mitochondrion, sarcotubule and in-terstitium volume density and surface density of mitochondrial cristae and numerical density of mitochondria between trained and control group aged 8 and 15 months. In the trained 25 months group, significant increase in volume density of interstitium, lipofucsin granule were shown as compared to untrained age-matched control. On the other hand, significant decrease in mitochondrion volume density was shown. The myofibril volume density did not differ between trained and control group although trained group showed slight increase. From the data obtained a reduced mitochondria/myofibrils ratio was found in trained rat heart aged 25 months and there was no difference between trained and control rat aged 15 months. But a slight but not significant increase was found in the trained group aged 8 months as compared with same age control group. Such increase in the ratio in young animals is considered to be of great importance to cardiac pumping and adaptability. Whereas such adaptations don't seem to occur in aged heart muscle. This study proposed that repeated endurance exercise do not cause any significant qualitative and quantitative ultrastructural change of heart muscle in young(3months) and adult (10months) suggesting that the heart is able to adapt to the exercise. On the contrary, the repeated endurance exercise stress may actually induce degenerative changes in the aged heart muscle(20months).

• Journal of the Korean Geotechnical Society
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• v.32 no.10
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• pp.41-53
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• 2016

Stability of the braced earth wall in the composite ground, which is composed of the jointed base rocks and the soil strata depends on the earth pressure acting on it. In most cases, the earth pressure is calculated by the empirical method, in which base rocks are considered as a soil strata with the shear strength parameters of base rocks. In this case the effect of the joint dips of the jointed base rocks is ignored. Therefore, the calculated earth pressure is smaller than the actual earth pressure. In this study, the magnitude and the distribution of the earth pressure acting on the braced wall in the composite ground depending on the joint dips of the base rocks and the ratio of soil strata and base rocks were experimentally studied. Two dimensional large-scale model tests were conducted in a large scale test facility (height 3.0 m, length 3.0 m and width 0.5 m) by installing 10 supports in a scale of 1/14.5. The test ground was presumed with the base rock ratio of the composite ground of 65%:35% and 50%:50% and with the joint dips for each base rock layer, $0^{\circ}$, $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$, respectively. And then finite element analyses were performed in the same condition. As results, the earth pressure on the braced wall increased as the base rock layer's joint dips became larger. And earth pressure at the rock layer increased as the rock rate became larger. The largest earth pressure was measured when the base rock rate was 50% (R50) and the rock layer's joint dips was $60^{\circ}$. Based on these results, a formular for the calculation of the earth pressure in the composite ground could be suggested. Distribution of earth pressure was idealized in a quadrangular form, in which the magnitude and the position of peak earth pressure depended on the rock ratio and the joint dips.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.1
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• pp.18-29
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• 2010

Offshore subsurface storage of $CO_2$ is regarded as one of the most promising options to response severe climate change. Marine geological storage of $CO_2$ is to capture $CO_2$ from major point sources, to transport to the storage sites and to store $CO_2$ into the offshore subsurface geological structure such as the depleted gas reservoir and deep sea saline aquifer. Since 2005, we have developed relevant technologies for marine geological storage of $CO_2$. Those technologies include possible storage site surveys and basic designs for $CO_2$ transport and storage processes. To design a reliable $CO_2$ marine geological storage system, we devised a hypothetical scenario and used a numerical simulation tool to study its detailed processes. The process of transport $CO_2$ from the onshore capture sites to the offshore storage sites can be simulated with a thermodynamic equation of state. Before going to main calculation of process design, we compared and analyzed the relevant equation of states. To evaluate the predictive accuracies of the examined equation of states, we compare the results of numerical calculations with experimental reference data. Up to now, process design for this $CO_2$ marine geological storage has been carried out mainly on pure $CO_2$. Unfortunately the captured $CO_2$ mixture contains many impurities such as $N_2$, $O_2$, Ar, $H_{2}O$, $SO_{\chi}$, $H_{2}S$. A small amount of impurities can change the thermodynamic properties and then significantly affect the compression, purification and transport processes. This paper analyzes the major design parameters that are useful for constructing onshore and offshore $CO_2$ transport systems. On the basis of a parametric study of the hypothetical scenario, we suggest relevant variation ranges for the design parameters, particularly the flow rate, diameter, temperature, and pressure.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.259-267
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• 2006

Hydraulic conductivity is the rate of water flux on hydraulic gradient. The van Genuchten Mualem (VGM) model is frequently used for describing unsaturated state of soils, that is composed with the function of soil water potential and soil water content and requests various parameters. This study is to get the value of VGM parameters used Rosetta computer program based on neural network analysis method and to calculate VGM parameters. VGM parameters included Ko(effective saturated hydraulic conductivity), ${\theta}r$(residual soil water content), ${\theta}s$(saturated soil water content), L, n and m. The unsaturated hydraulic conductivity at 10 kPa was calculated by using Rosetta program. Unsaturated hydraulic conductivities of 17 soil series at 1, 3, 5, 7 kPa were also obtained by applying saturated hydraulic conductivity by disk tension infiltrometer based on Gardner and Wooding's equation. Water flow at the water potential of 3 kPa was very low except Namgye, Hagog, Baegsan, Sangju, Seogcheon, Yesan soil series. Unsaturated hydraulic conductivity at 1 kPa showed the highest value for Samgag soil series and was in order of Yesan, Hwabong, Hagog and Baegsan soil series. Those of Gacheon, Seocheon and Ugog soil series were very low. When the value by VGM was compared with the value by disc tension infiltrometer, there was a tendency with exponential function to soils without gravel but there was no tendency to soils including gravel. Conclusively, it would be limited that VGM model for unsaturated hydraulic conductivity analysis applies to Korean agricultural land including gravel and having steep slope, shallow soil depth.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.1
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• pp.47-58
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• 2002

Much of the plastic film house soils in the southern part of the Korean peninsula are managed using a upland-paddy rotation culture system (hereafter, RS) to prevent salt accumulation in soil. However, information on the effects of RS on soil properties and environmental conservation is limited. In order to determine the effects of RS on soil properties, 22 fields under RS and 20 fields under a non-rotation system (hereafter, NRS) in plastic film houses were selected in Chinju, in southern Korea, and the P distribution characteristics were investigated, including the chemical properties. The RS contributed to the removal of water-soluble salts in the surface layer and to the redistribution of organic matter evenly in the soil profile. In the AP horizon, available phosphorus levels were $1,611mg\;kg^{-1}$ in RS and $1,789mg\;kg^{-1}$ in NRS, which markedly exceeds the optimum range for plant cultivation. Total P was lower in RS (average $4,593mg\;kg^{-1}$) than in NRS (average $5,440mg\;kg^{-1}$) and this decrease was taken to be an effect of RS. Inorganic P was the predominant form of P in both systems, followed by organic P and residual P. A soil profile showed that total and inorganic P concentrations decreased with depth in both systems. However, organic P increased withdepth in RS, which was in contrast to that noted in NRS. The increase in organic P with depth in RS implied that organically rather than inorganically derived phosphate moved through the soil. The concentrations of water-soluble P, Ca-P and Al-P were higher in NRS than in RS soil profiles, but the Fe-P concentration was higher in RS than in NRS, which might be affected by the anaerobic conditions found in paddy soils. In both systems, the Al-P form of extractable P predominated in the surface layer, followed by Ca-P, Fe-P and water-soluble P. With increasing depth, the composition rate of Ca-P to extractable P decreased to less than 10% in the 60-70cm depth, as Fe-P dominated at this level. The content of water-soluble P, potentially the main source of eutrophication, was higher in NRS than in RS. These results indicated that the RS used in plastic film houses contributed to the removal of water-soluble salts but only slightly decreased the phosphate concentration.

• Journal of Korean Classical Literature and Education
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• no.34
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• pp.149-191
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• 2017

This study examines Korean language translations of traditional Chinese hansi in the 1910s and 1920s. In the $20^{th}$ century, many poets translated Chinese and Korean traditional hansi into Korean. In the early $20^{th}$ century, Korean language began to be used as a national public language. At that time, not only hansi but also poetry from several other languages had been translated into Korean. Choi Nam-sun in the 1910s and Kim So-woel, Kim Eok, and Lee Kwang-su in the 1920s translated Chinese traditional hansi, focusing on famous Dang dynasty poetry from Tu Fu and Li Bai, etc. Choi Nam-sun's translation in the 1910s aimed to consider poetry as a written literature. On the contrary, Kim So-woel, Kim Eok, and Lee Kwang-su believed that Korean modern verse literature should be songs as well as poetry, and their translations in the 1920s aimed to create songs as spoken literature by focusing on orality and universality. Though Korean is now the language, the literary history of hansi continues in modern poetry.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.67-72
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• 2005

To investigate the feasibility of a new concept of storing Liquefied Natural Gas (LNG) in a lined hard rock cavern, and to develop essential technologies for constructing underground LNG storage facilities, a small pilot plant storing liquid nitrogen (LN2) has been constructed at the Korea Institute of Geoscience and Mineral Resources (KIGAM). The LN2 stored in the cavern will subject the host rock around the cavern to very low temperatures, which is expected to cause the development of an ice ring and the change of ground condition around the storage cavern. To investigate and monitor changes in ground conditions at this pilot plant site, geophysical, hydrogeological, and rock mechanical investigations were carried out. In particular, geophysical methods including borehole radar and three-dimensional (3D) resistivity surveys were used to identify and monitor the development of an ice ring, and other possible changes in ground conditions resulting from the very low temperature of LN2 in the storage tank. We acquired 3D resistivity data before and after storing the LN2, and the results were compared. From the 3D images obtained during the three phases of the resistivity monitoring survey, we delineated zones of distinct resistivity changes that are closely related to the storage of LN2. In these results, we observed a decrease in resistivity at the eastern part of the storage cavern. Comparing the hydrogeological data and Joint patterns around the storage cavern, we interpret this change in resistivity to result from changes in the groundwater flow pattern. Freezing of the host rock by the very low temperature of LN2 causes a drastic change in the hydrogeological conditions and groundwater flow patterns in this pilot plant.

• Journal of Korean Philosophical Society
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• v.131
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• pp.199-222
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• 2014

This essay aims at clarifying Dasan Jeong Yagyong's view on Jingfang's yaobian theory. As is well known, Jingfang was a scholar of the Earlier Han period who exerted a profound influence on the theoretical development of Xiangshu School by creating the various techniques for interpreting the Zhouyi. Jingfang is also important in relation with Dasan's commentary of the Zhouyi, because some part of Dasan's interpreting techniques are thought to have their origin in Jinfang. For example, Dasan used the bigua theory of which the origin could be traced back into Jingfang. However, in this article, I did not deal with the bigua theory because I am going to write another article about it. In stead, my focus will be put on analyzing how Dasan evaluated Jingfang's yaobian theory. The main issues of my argument can be summarized as following. Firstly, in terms of yaobian, Jeong Yagyong called attention to Jingfang's annotation on the Zhouyi in which Jingfang utilized the yaobian method in three occasions, i.e., the first nine of the Qian(乾初九), the sixth nine of the Guan(觀上九), and the sixth nine of the Bo(剝上九). It seems that Jeong Yagyong set forth enough evidence about Jingfang's use of yaobian at least in relation to two cases of the first nine of the Qian and the sixth nine of the Bo, while the other evidence of the sixth nine of the Guan was not so persuasive. However, even if it is evident that Jingfang made use of the yaobain in two cases, there is no reason to equate it with that of Dasan. If one takes a close look, it becomes clear that Jingfang's way of yaobain is very different from Dasan's. Secondly, Jeong Yagyong mentioned Jiayi(賈誼) who lived about one hundred years before Jingfang, as the person who utilized the yaobian in his book of Xinshu(新書). If it is certain that Jiayi was aware of the yaobian, we can assume that the yaobian technique had been handed down from Jiayi to Jingfang. The manuscript excavated from the Mawangdui tomb also increases the possibility that Jiayi could have had the knowledge on the yaobian. In the chapter of Muhe(繆和) of the Mawangdui Zhouyi, there appears the phrase, i.e., "the first six of the qian, qian goes to mingyi," which shows exactly the same form of the yaobian in the Mr Zuo's Spring and Autumn Annals(春秋左氏傳). The burial period of Mawangdui tomb is estimated at the same year of B.C.168 in which Jiayi died. Therefore, judging from that fact, it becomes evident that the yaobain method was widely diffused around B.C.168. Subsequently, it is possible to infer that the yaobian method had been handed down from the period of Jiayi to Jingfang. If we could present the persuasive evidence to support that inference, it would also have the effect of consolidating Dasan's argument about the yaobian.

• The Journal of Korean Philosophical History
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• no.41
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• pp.129-154
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• 2014

The study examined Daxuezhalu written by ShiTan Li Shen-Yi. Three different editions of Daxuezhalu were looked into, one of which in Shitanji("石灘集") could be considered methodical, if not perfect. In addition, Guojirucangben("國際儒藏本" as goudou(句讀) and correction was made on its wrong contents through dainjiao(點校) by WangXinzhu(王心竹). For these reasons, Daxuezhalu in Shitanji was used as the basis for the study and Guojirucangben as a supplement. Explanatory notes were added to Daxuezhangjuxu("大學章句序") in Daxuezhalu, but consent cannot be given to some of them, which include the author's opinion that views Jing(敬) as essence of Xiaoxue("小學") and Daxue("大學"), and the unique interpretation of Zhangju(章句), which can be attributed to the fact that the author didn't revise Daxuezhalu after writing it at the age of 37. However, the explanatory notes on xin(心), xing(性), qing(情), zhi(志) and yi(意) in An(按) toward the end of Daxuezhangjuxu are considered unique. The followings in Jingwen(經文) were examined as questionable. ShiTan(石灘) reflected on the ways to reach zhishan(至善) as in the table that shows Sangangling(三綱領), which may be viewed as distinctive. The review of zhizhijie('知止'節) reveals that ShiTan(石灘) followed Zhuzi(朱子) on the issue of whether to relocate zhizhijie('知止'節) through his interpretation for leaving it where it was. The same was applied regarding tizhi(體制) in chuanwen(傳文) by following Zhuzi(朱子)'s argument on Daxuezhangju("大學章句"). While the tendency to divide it into zhi(知) and hang(行) was seen, there was difficulty in thorough understanding with all the comments being in goujie(句節). It is considered overreaction that he argued in favor of shen(?) without any comments on Gewuzhizhibuwangzhang("格物致知補忘章"), although he mentioned characters, jin(謹) and shen(?) unlike Zhuzi(朱子).

• Journal of Korea Water Resources Association
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• v.55 no.6
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• pp.447-459
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• 2022

This study estimated the grid-type precipitation quantile for the Korean Peninsula using PERSIANN-CCS-CDR (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System-Climate Data Record), a satellite based re-analysis precipitation data. The period considered is a total of 38 years from 1983 to 2020. The spatial resolution of the data is 0.04° and the temporal resolution is 3 hours. For the probability distribution, the Gumbel distribution which is generally used for frequency analysis was used, and the probability weighted moment method was applied to estimate parameters. The duration ranged from 3 hours to 144 hours, and the return period from 2 years to 500 years was considered. The results were compared and reviewed with the estimated precipitation quantile using precipitation data from the Automated Synoptic Observing System (ASOS) weather station. As a result, the parameter estimates of the Gumbel distribution from the PERSIANN-CCS-CDR showed a similar pattern to the results of the ASOS as the duration increased, and the estimates of precipitation quantiles showed a rather large difference when the duration was short. However, when the duration was 18 h or longer, the difference decreased to less than about 20%. In addition, the difference between results of the South and North Korea was examined, it was confirmed that the location parameters among parameters of the Gumbel distribution was markedly different. As the duration increased, the precipitation quantile in North Korea was relatively smaller than those in South Korea, and it was 84% of that of South Korea for a duration of 3 h, and 70-75% of that of South Korea for a duration of 144 h.