• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.811-823
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• 2019

Slip form method is applied to many cases of a shaft these days because it is safer, more economical and faster than cast-in-place method. Slip-up height of the method is approximately 2.5 to 4.0 m/day. If the temperature of concrete is outside the range of 10 to 30℃, the effects of changes in strength or elastic characteristics are significant. Therefore, it is difficult for slip-up speed to be higher than 3 m/day during winter construction. In addition, concrete has heat caused by hydration, which causes temperature cracking of hardened concrete. Therefore, temperature control of concrete curing is necessary for the continuous slip-up of slip form. In this study, the rebound hardness, time of ultrasonic waves propagation, heat of hydration, and external temperature are measured by developing heating panels and test devices for the continuous slip-up. Based on this, heating slip form is manufactured; this was applied to "Kimpo sites" and "Sinwol sites". The compared slip-up speed samples were 1.9 m/day or 0.200 m/hr on average at Gimpo sites (08:00~17:30) and 2.0 m/day or 0.210 m/hr at Sinwol sites.

• Environmental Engineering Research
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• v.10 no.5
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• pp.213-226
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• 2005

To treat wastewater efficiently by a one-step process of nitrogen removal, a new bacterial strain producing $N_2$ gas from ${NH_4}^+$ under an aerobic condition was isolated and identified. The cell was motile and a Gram-negative rod, and usually occurred in pairs. By 16S-rDNA analysis, the isolated strain was identified as Enterobacter asburiae with 96% similarity. The isolate showed that the capacity of $N_2$ production under an oxic condition was approximately three times higher than that under an anoxic condition. Thus, the consumption of ${NH_4}^+$ by the isolate was significantly different in the metabolism of $N_2$ production under the two different environmental conditions. The optimal conditions of the immobilized isolate for $N_2$ production were found to be pH 7.0, $30^{\circ}C$ and C/N ratio 5, respectively. Under all the optimum reaction conditions, $N_2$ production by the immobilized isolate resulted in reduction of ORP with both the consumption of DO and the drop of pH. The removal efficiencies of $COD_{Cr}$, and TN were 56.1 and 60.9%, respectively. The removal rates of $COD_{Cr}$, and TN were the highest for the first 2.5 hrs with the removal $COD_{Cr}/TN$ ratios of 32.1, and afterwards the rates decreased as reaction proceeded. For application of the immobilized isolate to a practical process of ammonium removal, a continuous operation was executed with a synthetic medium of a low C/N ratio. The continuous bioreactor system exhibited a satisfactory performance at 12.1 hrs of HRT, in which the effluent concentrations of ${NH_4}^+$-N was measured to be 15.4 mg/L with its removal efficiency of 56.0%. The maximum removal rate of ${NH_4}^+$-N reached 1.6 mg ${NH_4}^+$-N/L/hr at 12.1 hrs of HRT(with N loading rate of $0.08\;Kg-N/m^3$-carrier/d). As a result, the application of the immobilized isolate appears a viable alternative to the nitrification-denitrification processes.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.7
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• pp.706-713
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• 2010

The research seeks to find the optimal conditions for sonodegradation of naphthalene and phenol as exemplary organic pollutants to be subjected to ultrasound in varying frequencies (28 kHz, 580 kHz, and 1,000 kHz) and in the presence of different kinds of additive (T$TiO_2$, $H_2O_2$, $FeSO_4$, Zeolite, and Cu). In cases of both naphthalene and phenol, 580 kHz of ultrasound has proven to be the most effective among others at sonodegradation. Based on the observation that OH radicals are also produced in maximum under exposure of 580 kHz of ultrasound, we concluded that this frequency of ultrasound creates hospitable condition for the combined process of degradation by pyrolysis and oxidization. $FeSO_4's$ degradation rate and k1 value have increased by approximately 1.8 times compared with the results of the solutions without any additives. This seems to be the result of ultrasound reaction which, accompanied by Fenton's reaction, increased the oxidative degradation and the production of OH radicals. However, application of ultrasound and Fenton's reaction is limited to the batch type conditions, as its use in continuous system can cause loss of iron or decay of the cistern, thereby creating additional pollutants. When the additive is replaced with $TiO_2$, on the contrary, the rate of sonodegradation has increased up to 20% compared to when there was no additive. We therefore conclude that $TiO_2$ could prove to be an effective additive for ultrasound degradation in continuous treatment system.

• Journal of Forest and Environmental Science
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• v.32 no.4
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• pp.353-366
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• 2016

The effect of different environmental conditions and altitudes on the growth and reproductive characteristics in 12 teak plantations at 4 different blocks (Cauvery canal bank, Topslip and Parambikulam (Tamil Nadu), Nilambur and Wayanad (Kerala) of Southern India was investigated. The annual rainfall and mean monthly temperature of the study areas varied significantly from 1390 to 3188 mm and 16 to $38^{\circ}C$ respectively. The teak plantations in Cauvery canal bank which grow in continuous moisture condition (8-10 months) retain the leaf for longer period due to moisture resulting continuous supply of photosynthates leads to fast and outstanding growth. The girth at breast height (GBH) of 34-years-old tree in canal area was similar to that of 40 to 49-years-old trees in other locations, indicating that teak plantations with regular watering and silvicultural practices may be harvested at the age of 30 years. The leaf fall, flowering and fruiting showed significant variations in different teak plantations due to environmental factors and altitudes. It was found that increase of rainfall enhances number of flowers in the inflorescence in teak. Tholpatty (block-IV) showed more flowering in a inflorescence (3,734-3,744) compared to other plantations (1,678-3,307). Flowering in Nilambur and Wayanad coincided with heavy rainfall resulting low fruitset (1.1-2.3%) probably heavy rainfall ensuing restriction of pollinators for effective pollination. On the other hand, flowering in Cauvery canal bank (Block-I) was not coincided with high rainfall exhibited high fruitset (2-3%). About 66 to 76% of the fruits in different plantations were empty, and it is one of the main reasons for poor germination in teak. The seeds of Topslip and Parambikulam (Block-II) showed higher seed weight, maximum seed filling and good germination indicating that the environmental factors and altitude play significant role in fruit setting and seed filling in teak. In addition, the teak plantations in Topslip and Parambikulam showed good growth suggesting that plantations in the altitude range of approximately 550-700 m may be suitable for converting into seed production areas for production of quality seeds.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.9
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• pp.1520-1532
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• 2020

Objective: Due to rapid economic return, mixed crop-swine farming systems in Korea have become more intensive. Intensive farming practices often cause nutrient surpluses and lead to environmental pollution. Nutrient budgets can be used to evaluate the environmental impact and as a regulatory policy instrument for nutrient management. This study was conducted to select a nutrient budgeting approach applicable to the mixed crop-swine farms in Korea and suggest an effective manure treatment method to reduce on-farm nutrient production. Methods: In this study, we compared current and ideal gross nutrient balance (GNB) approaches of Organisation for Economic Co-operation and Development and soil system budget (SSB) approach with reference to on-farm manure treatment processes. Data obtained from farm census and published literature were used to develop the farm nutrient budgets. Results: The average nitrogen (N) and phosphorus (P) surpluses were approximately 11 times and over 7 times respectively higher in the GNB approaches than the SSB. After solid-liquid separation of manure, during liquid composting a change in aeration method from intermittent to continuous reduced the N and P loading about 50% and 47%, respectively. Although changing in solid composting method from turning only to turning+aeration improved the N removal efficiency by 30.5%, not much improvement in P removal efficiency was observed. Conclusion: Although the GNB approaches depict the impact of nutrients produced in the mixed crop-swine farms on the overall agricultural environment, the SSB approach shows the partitioning among different nutrient loss pathways and storage of nutrients within the soil system; thus, can help design sustainable nutrient management plans for the mixed cropswine farms. The study also suggests that continuous aeration for liquid composting and turning+aeration for solid composting can reduce nutrient loading to the soil.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.317-330
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• 2009

To diminish the levels of organic matters, a novel S-CROM (continuous removal of organic matters in the stream system using freshwater bivalve), was developed and applied to the polluted stream discharging from the wastewater treatment plant, Pocheon stream, Pocheon city (Korea). Major pollutants of the stream were human population and industrial wastewaters. The study was conducted at a small dam constructed within the stream, often called 'bo', and designed with four tanks; no mussels and no sediment (negative control), no mussels and sediment (positive control), 30 mussels and sediment (D1), and 60 mussels and sediment (D2). Physicochemical and biological parameters were measured at 12 hours interval (day and night) after mussel stocking. Results indicated that Anodonta woodiana Lea (D2) clearly removed approximately 72% of chl-$\alpha$ and 57% of suspended solids on second day, however, there were no differences in removal activities between animal densities (P>0.5). Dislike a laboratory CROM system, which previously developed, there were no huge release of nutrient ($NH_3$-N and SRP), due perhaps to the higher flow rate and the lower animal density. Therefore, we may suggest that if we can determine the relevant current and the animal density considering the stream state, an S-CROM system has a strong potential to water quality improvement of eutrophic streams. Some characteristics on both CROM and S-CROM were compared.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.1-7
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• 1997

We have monitored nutrients, chlorophyll, suspended solids, and salinity in the Keum Estuary to understand the temporal fluctuation of oceanographic parameters and to illustrate any variation due to the gate operation of the Keum River Dike from June, 1995 to September, 1996, approximately for 500 days. Tidal range is used as the key factor to explain the fluctuations and atmospheric parameters such as air temperature, wind velocity and rainfall are also used supplementally. The fresh water discharge was selected as another major impact on the estuarine environment due to the gate operation of the Keum Dike. In addition, daily variation by tidal cycle was investigated twice in April and July, 1996. In diurnal variation, salinity was positively correlated with tidal elevation, whereas negatively correlated with nutrients. Relatively high suspended solid and chlorophyll contents were found in the period between high and low tide. In 500 days continuous observations, salinity was negatively correlated with the volume of fresh-water discharge, but positively correlated with nutrients. A major chlorophyll bloom occurred in spring. A similar pattern of variation was observed between suspended solid and the neap-spring tidal cycle. In comparison with the data of the Keurn Estuary before the gate operation of the Keum River dike, fresh-water discharge predominated other environmental factors during the rainy season. In addition, the velocity of tidal current and the concentration of suspended solid were decreased, while nutrients and chlorophyll contents were increased.

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.73-82
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• 1998

Purpose : A precise NMR technique for measuring the rate of water exchange and cell membrane permeability across the hepatocyte membrane using liver-specific MR contrast agent is described. Materials and Methods : The rat hepatocytes isolated by perfusion of the livers were used for the NMR measurements. All experiments were performed on an IBM field cycling relaxometer operating from 0.02MHz to 60 MHz proton Larmor frequency. spin-echo pulse sequence was empolyed to measure spin-lattice relaxation time, T1. The continuous distribution analysis of water proton T1 data from rat hepatocytes containing low concentrations of the liver specific contrast agent, Gd-EOB-DTPA, modeled by a general two compartment exchange model. Results : The mean residence time of water molecule inside the hepatocyte was approximately 250 msec. The lower limit for the permeability of the hepatocyte membrane was $(1.3{\pm}0.1){\;}{\times}{\;}10^{-3}cm/sec$. The CONTIN analysis, which seeks the natural distribution of relaxation times, reveals direct evidence of the effect of diffusive exchange. the diffusive water exchange is not small in the intracellular space in the case of hepatocytes. Conclusions : Gd-EOB-DTPA, when combined with continuous distribution analysis, provides a robust method to study water exchange and membrane permeability in hepatocytes. Water exchange in hepatocyte is much slower thatn that in red blood cells. Therefore, tissue-specific contrast agent may be used as a functional agent to give physiological information such as cell membrane permeability.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.610-617
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• 1995

Sleep apnea occurs in approximately 50% of patients with acromegaly, and sleep apnea is associated with increased cardiovascular diseases and mortality. In view of these findings, sleep apnea may be a factor in the increased incidence of cardiovascular deaths in acromegaly patients. We experienced a case of active acromegaly patient, 54-yr-old man, associated with obstructive sleep apnea syndrome, congestive heart failure with dilated cardiomyopathy and serious cardiac arrhythmias. He was treated for obstructive sleep apnea syndrome, diagnosed by overnight polysomnography, with nasal continuous positive airway pressure(CPAP) for 4 months, which successfully controlled his loud snoring, sleep apnea, nocturnal hypoxemia and apnea-related symptoms. And also he was treated for underlying acromegaly and cardiac complications with bromocriptine and cardiogenic drugs for 4 months, but still had elevated growth hormone(GH) and insulin like growth factor-1(IGF-1) levels and serious cardiac arrhythmias. We describe our experience about the effect of CPAP treatment in an active acromegaly patient associated with obstructive sleep apnea syndrome and cardiac complications with review of literature.

• Journal of muscle and joint health
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• v.3 no.2
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• pp.135-150
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• 1996

This study was performed to analyze the patient's experience during the progress of disease in the patients with osteoarthritis, who are taken the replacement surgery of knee Joint. The examine was consisted of five patients with osteoarthritis, who are taken the replacement surgery of knee joint from Dec. 4. 1995 to May, 20, 1996 at C university hospital. After hospitalization, the physical and psycho-logical status of the patients during preoperation, postoperation and discharge was examined. The data were examined according to the ethnographic method. The results are as follows. The patients experienced the periods of embarrasment, conflict, before surgery suffering, acceptance period after surgery. In the embarrasment period, the patients take a multiple medication therapy including hospital treatment, oriental medication and folk medication to ameliorate joint pain after first diagnosis on arthritis. The embarrasment period includes compulsive drug medication, oriental medication, folk medication, trouble some, sadness and survey of hospitals. In the conflict period, the patients consider the operation of knee because of working difficulty and severe Joint Pain, while they feel anxiety about the surgery. They condemn their physical situations. They have the conflict and anxiety on surgical operation. they consider the quality of life. They hope the surgery makes patients to improve walking ability. This period includes self-condemned, sorry, tiresomeness, expectation, worrisomeness, anxiety and hesitance. In the suffering period, the patients experience post operation physical discomfort after the total knee replacement. They do physical exercise, including extension and straight leg raising to maintain walking ability, while they endure to wait approximately 6 months for normal walking movements and they are also unstable to environmental people's sight. This period includes postoperative pain, continuous discomfort, inability and communication difficulty to other's people. In the acceptance period, the patients consider longerity of artificial Joint and also endure mild remaining joint pain. Some of them have religions for their wellbeing of life. This period include a self-protesting policy, abandonment, self-consolation, dependence on religions. According to the result from this study I suggested these shown below. 1) After replacement surgery of knee joint, continuous investigation on outcome patient is necessary. 2) It is also necessary to analyze on patient's experiences, who are taken the replacement surgery of hip Joint. 3) Study on disease experiences of patients with rhematoid arthritis, who take drug medication and physical therapy alone without surgery, is necessary. 4) Investigation on patient's favorable folk medication may be helpful to analyze disease experience of patients with osteoarthritis.