• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.3
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• pp.105-116
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• 2022

Seismic demand on nonstructural components (NSCs) is highly dependent on the coupled behavior of a combined supporting structure-NSC system. Because of the inherent complexities of the problem, many of the affecting factors are inevitably neglected or simplified based on engineering judgments in current seismic design codes. However, a systematic analysis of the key affecting factors should establish reasonable seismic design provisions for NSCs. In this study, an idealized 2-DOF model simulating the coupled structure-NSC system was constructed to analyze the parameters that affect the response of NSCs comprehensively. The analyses were conducted to evaluate the effects of structure-NSC mass ratio, structure, and NSC nonlinearities on the peak component acceleration. Also, the appropriateness of component ductility factor (R_p) given by current codes was discussed based on the required ductility capacity of NSCs. It was observed that the responses of NSCs on the coupled system were significantly affected by the mass ratio, resulting in lower accelerations than the floor spectrum-based response, which neglected the interaction effects. Also, the component amplification factor (a_p) in current provisions tended to underestimate the dynamic amplification of NSCs with a mass ratio of less than 15%. The nonlinearity of NSCs decreased the component responses. In some cases, the code-specified R_p caused nonlinear deformation far beyond the ductility capacity of NSCs, and a practically unacceptable level of ductility was required for short-period NSCs to achieve the assigned amount of response reduction.

• Journal of Environmental Health Sciences
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• v.49 no.3
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• pp.149-158
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• 2023

Background: Injury is one of the major health problems in South Korea. Few studies have evaluated both intentional and unintentional injury when investigating the association between exposure to air pollutants and injury. Objectives: We aimed to explore the association between short-term exposure to ambient air pollution and years of life lost (YLLs) due to injury. Methods: Data on daily YLLs for 2002~2019 were obtained from the the Death Statistics Database of the Korean National Statistical Office. This study estimated short-term exposure to particulate matter with an aerodynamic diameter of <10 ㎛ (PM₁₀), particulate matter with an aerodynamic diameter of <2.5 ㎛ (PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃). This time series study was conducted using a generalized additive model (GAM) assuming a Gaussian distribution. We also evaluated a delayed effect of ambient air pollution by constructing a lag structure up to seven days. The best-fitting lag was selected based on smallest generalized cross validation (GCV) value. To explore effect modification by intentionality of injury (i.e., intentional injury [self-harm, assault] and unintentional injury), we conducted stratified subgroup analyses. Additionally, we stratified unintentional injury by mechanism (traffic accident, fall, etc.). Results: During the study period, the average daily YLLs due to injury was 307.5 years. In the intentional injury, YLLs due to self-harm and assault showed positive association with air pollutants. In the unintentional injury, YLLs due to fall, electric current, fire and poisoning showed positive association with air pollutants, whereas YLLs due to traffic accident, mechanical force and drowning/submersion showed negative associations with air pollutants. Conclusions: Injury is recognized as preventable, and effective strategies to create a safe society are important. Therefore, we need to establish strategies to prevent injury and consider air pollutants in this regard.

• Korean Journal of Legislative Studies
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• v.27 no.2
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• pp.111-143
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• 2021

It is necessary to analyze the budget power during the budget process of the local council, paying attention to strengthening the capacity of local council and reinforcing expertise to secure accountability. The budget power of council is expressed in various terms such as power of the purse and the authority to control the budget, and focuses on the role of control and check in the council's budget process. The purpose of this study is to analyze the factors that political·administrative variables, social·economical variables affect the budget power of local council. The budget power of councils was set as the budget net modification rate and the period for processing the budget bill at the plenary session. And the effects of various variables were checked. As a result, the local council confirmed that there was a lack of checks and controls in the budget process.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.19 no.2
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• pp.84-92
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• 2023

As temporary storage facilities for spent nuclear fuels in domestic nuclear power plants are expected to be saturated, external intermediate storage facilities would be required in the future. Spent nuclear fuels are stored in metal canisters and then placed in a dry environment within concrete or metal casing for operation. In the United States, the dry storage method for spent nuclear fuels has been operated for an extended period. Based on the corrosion experiences of dry storage canisters in chloride environments, numerous studies have been conducted to reduce corrosion in welds. With the construction of intermediate storage facilities in Korea for spent nuclear fuels expected near coastal areas adjacent to nuclear power plants, there is a need for research on the corrosion occurrence of welds and mitigation methods for canisters in chloride environments. In this paper, we measured and compared the residual stresses in the Heat-Affected Zones (HAZ) after electron beam welding (EBW) and gas tungsten arc welding (GTAW) processes for candidate materials such as 304L, 316L, and duplex stainless steel(DSS). We investigated the possibility of microstructure control through the application of surface modification processes using friction stir processing (FSP). Corrosion tests on each welded specimen revealed a higher corrosion rate in EBW welds compared to GTAW. Furthermore, it was confirmed that corrosion resistance improved due to phase refinement and redistribution of precipitates when FSP was applied.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.122-127
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• 2010

Purpose: The objective of this study was to investigate the effects of calcium phosphate coated titanium implant surface on bone response and implant stability at early stage of healing period of 3 weeks and later healing period of 6 weeks. Material and methods: A total of 24 machined, screw-shaped implants (Dentium Co., Ltd., Seoul, Korea) which dimensions were 3.3 mm in diameter and 5.0 mm in length, were used in this research. All implants (n = 24), made of commercially pure (grade IV) titanium, were divided into 2 groups. Twelve implants (n = 12) were machined without any surface modification (control). The test implants (n = 12) were anodized and coated with thin film (150nm) of calcium phosphate by electron-beam deposition. The implants were placed on the proximal surface of the rabbit tibiae. The bone to implant contact (BIC) ratios was evaluated after 3 and 6 weeks of implant insertion. Results: The BIC percentage of calcium phosphate coated implants ($70.8{\pm}18.9%$) was significantly higher than that of machined implants ($44.1{\pm}16.5%$) 3 weeks after implant insertion (P = 0.0264). However, there was no significant difference between the groups after 6 weeks of healing (P > .05). Conclusion: The histomorphometric evaluation of implant surface revealed that; 1. After 3 weeks early healing period, bone to implant contact (BIC) percentage of calcium phosphate coated implants (70.8%) was much greater than that of surface untreated machined implants (44.1%) with P = 0.0264. 2. After 6 weeks healing period, however, BIC percentage of calcium phosphate coated implants group (79.0%) was similar to the machined only implant group (78.6%). There was no statistical difference between two groups (P = 0.8074). 3. We found the significant deference between the control group and experimental group during the early healing period of 3 weeks. But no statistical difference was found between two groups during the later of 6 weeks.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.253-262
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• 1998

This study was performed to investigated the effect of dietary fat sources on renal senescence in aged rats. Seventeen month old male Sprague-Dawley rats were divided into 3 groups according to urinary protein excretion. Four month old rats were used as a control group. The rats were fed one of three different experimental diets ; 20% beef tallow, 20% corn oil 20% fish oil diet. They were fed experimental diets ad libitum for 16 weeks . The results are summarized as follows. Serum lipid concentrations were higher in aged rats than in control rats, with the beef tallow group showing the highest level, followed by the corn oil and fish oil groups. Old rats showed higher HDL and lower LDL levels than the control groups. Age and dietary fat had no effect on VLDL. GFR for the both age groups were increased with experimental period with the beef tallow group showing the highest value. Urinary protein excretion was also increased with experimental period in both age groups. There was a large increase in urinary protein in old rats that were fed beef tallow and corn oil, but not in old rats fed fish oil. On the contrary , the effect of dietary fat on urinary protein was not found in control groups. There was individual susceptibility in the effect of dietary fat on urinary protein. Old rats fed beef tallow with high initial urinary protein showed highest increase, but , the change was not significant in rats with a low initial value . It was also found that the increase was kept low in rats of the fish oil group with high initial urinary protein. The corn oil group showed in between values. There were no differences in urine and renal tissue concentrations of TXB2 . Aged rats showed a tendency of having higher urinary PGE2 excretion and lower renal cortex content. Since higher PGE2 excretion was reported to be associated with decreased renal function, this might suggest that the aged rats show renal function reduction. Light microscopic examination showed that glomerular segmental sclerosis, mesangial matrix expansion and tubular atrophy were more frequently present in aged rats, and that these changes were more significant in the beef tallow group, followed by corn oil and fish oil groups. The percentage of urinary protein excretion was increased in aged rats in association with increased glomerular sclerosis and mesangial matrix . This change could be partly due to a change in eicosanoids metabolism . Therefore, modification of dietary fat could affect the eicosanoids metabolism in kidney and renal senescence.

• The Korean Journal of Physiology
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• v.5 no.2
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• pp.45-54
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• 1971

That different mechanisms are involved in the secretory processes by the liver and the kidney of various dyes has been indicated by Sporter (1959), Kim and Hong (1963). Andrews (1958). suggested that a striking difference in the dye-secretory mechanism existed even in the same organ from species to species. Hence, the attempt has been made to study in the rabbit the secretory processes by the live. and the kidney of either phenol red (PSP), bromsulfalein (BSP) or green in the presence of Na-acetate, Na-taurocholate, P-Aminohippurate (PAH) or Benemid. In 37 rabbits, weighing about 2kg., anesthetized with ether, a dye was administered in such 8 manner that the plasma concentration was kept at a relatively constant level throughout the whole experimental period. Hepatic bile sad urine samples were quantitatively collected through the canulae which were previously inserted into the common bile duct (with the cystic duct ligated) and the urinary bladder, respectively, while arterial samples were taken from a femoral artery. After 50 min from the onset of dye administration, these samples were obtained every 10 mit for a period of 40 min. This was followed by the administration of either Na-acetate, Na-tauro-cholate, PAH or Benemid with a repetition of the same sample collecting procedures just stated. The results may be summarized as follows: 1) Na·acetate augmented urinary clearance of PSP by nearly 300 per cent, but lowered urinary BSP clearance by about 50 per cent. It enhanced biliary BSP clearance by 40% and had no effect on biliary psp clearance. 2) Na-taurocholate lowered biliary and urinary clearance of PSP by 10 per cent and 30 per cent respectively, and had no effect on both biliary and urinary clearance of BSP. 3) PAH lowered both biliary and urinary excretion of BSP and PSP, while it lowered the biliary excretion of indocyanine green which was excreted only in the bile. 4) Benemid suppressed BSP excretion by the liver and the kidney. 5) raper chromatographic analysis of PSP and of BSP in the bile and urine samples gave the following results: a) PSP Ivas excreted in the urine and bile only in free forms, and no modification in the excretory pattern was brought about by Na-taurocholate. b) BSP was excreted in the urine in 4 different conjugated froms and in the bile in both 3 different conjugated forms and in a free form. Na-taurocholate modified the excretory pattern of the urinary BSP.

• The Journal of Advanced Prosthodontics
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• v.1 no.2
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• pp.107-112
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• 2009

STATEMENT OF PROBLEM. Macroscopic and especially microscopic properties of implant surfaces play a major role in the osseous healing of dental implants. Dental implants with modified surfaces have shown stronger osseointegration than implants which are only turned (machined). Advanced surface modification techniques such as anodic oxidation and Ca-P application have been developed to achieve faster and stronger bonding between the host bone and the implant. PURPOSE. The purpose of this study was to investigate the effect of surface treatment of titanium dental implant on implant stability after insertion using the rabbit tibia model. MATERIAL AND METHODS. Three test groups were prepared: sandblasted, large-grit and acid-etched (SLA) implants, anodic oxidized implants, and anodized implants with Ca-P immersion. The turned implants served as control. Twenty rabbits received 80 implants in the tibia. Resonance frequencies were measured at the time of implant insertion, 2 weeks and 4 weeks of healing. Removal torque values (RTV) were measured 2 and 4 weeks after insertion. RESULTS. The implant stability quotient (ISQ) values of implants for resonance frequency analysis (RFA) increased significantly (P <. 05) during 2 weeks of healing period although there were no significant differences among the test and control groups (P >. 05). The test and control implants also showed significantly higher ISQ values during 4 weeks of healing period (P < .05). No significant differences, however, were found among all the groups. All the groups showed no significant differences in ISQ values between 2 and 4 weeks after implant insertion (P >. 05). The SLA, anodized and Ca-P immersed implants showed higher RTVs at 2 and 4 weeks of healing than the machined one (P < .05). However, there was no significant difference among the experimental groups. CONCLUSION. The surface-modified implants appear to provide superior implant stability to the turned one. Under the limitation of this study, however, we suggest that neither anodic oxidation nor Ca-P immersion techniques have any advantage over the conventional SLA technique with respect to implant stability.

• Archives of Plastic Surgery
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• v.36 no.5
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• pp.583-590
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• 2009

Purpose: In the cases of a vascular compromised condition in an injured lower extremity, soft tissue coverage with free tissue transfer presents a challenging problem to the reconstructive surgeon. For this reason, cross - leg flaps are still used in unusual circumstances. Advances in surgical technique has made the cross - leg free flap possible although it may require long operation time along with significant donor site morbidity. Therefore, a pedicled cross - leg muscle flap may be an alternative treatment modality when local flap or free flap is not possible. Methods: Twelve patients(9 males and 3 females) underwent the operation between October of 2001 and December of 2008. The patients' age ranged from 6 to 82 years. The unusual defects included the regions such as the knee, popliteal fossa, distal third of the tibia, dorsal foot, and the heel. Indications for the cross - leg gastrocnemius flap are inadequate recipient vessels for free flap(in eight cases), extensive soft tissue injuries(in three cases) and free flap failure(in one case). The muscle flap was elevated from contralateral leg and transferred to the soft tissue defect on the lower leg while both legs were immobilized with two connected external fixator systems. Delay procedure was performed 2 weeks postoperatively, and detachment was done after the establishment of the adequate circulation. The average period from the initial flap surgery to detachment was 32 days (3 to 6 weeks). Mean follow - up period was 4 years. Results: Stable coverage was achieved in all twelve patients without any flap complications. Donor site had minimal scarring without any functional and cosmetic problems. No severe complications such as deep vein thrombosis or flap necrosis were noted although mild to moderate contracture of the knee and ankle joint developed due to external fixation requiring 3 to 4 weeks of physical treatment. All patients were able to walk without crutches 3 months postoperatively. Conclusion: Although pedicled cross - leg flaps may not substitute free flap surgery, it may be an alternative method of treatment when free flap is not feasible. Using this modification of the gastrocnemius flap we managed to close successfully soft tissue defects in twelve patients without using free tissue transfers.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.4
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• pp.669-683
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• 2017

The objective of this study is to propose a modification of the previously proposed drainage system for catching the partial leakage of underground concrete structures. Two techniques were proposed for applying the drainage system only to the leaking parts. One was for conveying leaking groundwater to the collection point in the drainage system and the other was for conveying the collected groundwater to the primary drainage system of the underground concrete structure. Four waterproofing materials for conveying leaking groundwater to the catchment point of the drainage system, Durkflex made of porous rubber material, KE-45 silicone adhesive with super strong adhesion, Hotty-gel made of polymeric materials and general silicone adhesive were evaluated for waterproofing performance. Hotty-gel only showed perfect waterproof performance and the other three waterproof materials leaked. The modified drainage system with Hotty-gel and drainage pipe with fixed saddle to convey the leaking groundwater from the catchment point to the primary drainage system were tested on the concrete retaining wall. The waterproof performance and the drainage performance were evaluated by injecting 1,000 ml of water in the back of the modified drainage system at the 7-day, 14-day, 21-day, 28-day, 2-month and 3-month. There was no problem in waterproof performance and drainage performance of the modified drainage system during 3 months. In order to evaluate the construction period and construction cost of the modified drainage system, it was compared with the existing leaching repair method in surface cleaning stage, leakage treatment stage, and protective barrier stage. Total construction period and construction cost were compared in considering the contents of work, repair material, construction equipment, working time, and total number of workers. As a result of comparing and analyzing in each construction stage, it was concluded that the modified drainage system could save construction period and construction cost compared to the existing leaching repair method.