• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.6
• /
• pp.245-253
• /
• 2021

RC slab bridges account for the largest portion of deteriorated bridges in Korea. However, most RC slabs are not included in the first and second classes of bridges, which are subject to bridge safety management and maintenance. The highest damaged components in highway bridges are the subsidiary facilities including expansion joints and bearings. In particular, leakage through expansion joints causes deterioration and cracks of concrete and exposure of reinforced bars. Therefore, this study analyzed the effect of adhesion damage at expansion joints on the response of the deck in RC slab bridges. When the spacing between the expansion joints at both ends was closely adhered, cracks occurred in the concrete at both ends of the deck due to the resistance rigidity at the expansion joints. Based on the response results, the correlation analysis between displacements in the longitudinal direction of the expansion joint and concrete stress at both ends of the deck for each damage scenario was performed to investigate the effect of the occurrence of damage on the bridge behavior. When expansion joint devices at both sides were damaged, the correlation between displacement and stress showed a low correlation of 0.18 when the vehicles proceeded along all the lanes. Compared with those in the intact state, the deflections of the deck in the damaged case at both sides showed a low correlation of 0.34 to 0.53 while the vehicle passed and 0.17 to 0.43 after the vehicle passed. This means that the occurrence of cracks in the ends of concrete changed the behavior of the deck. Therefore, data-deriven damage detection could be developed to manage the damage to expansion joints that cause damage and deterioration of the deck.

• Korean Journal of Heritage: History & Science
• /
• v.38
• /
• pp.329-358
• /
• 2005

The Three storied Stone pagoda in Gameunsa Temple site, one of the early staged stone pagodas, has been known as a standard for Silla stone pagodas. A stone pagoda is not only a stone art work and but also a stone structure. Most studies and investigation of the stone pagoda has done mainly based on style and chronological research according to an art historical view. However, there is not an attempt to research the stone pagoda as a stone architecture. Most Korean experts at the stone pagoda has art history in their background. Engineers who can understand the structure of the stone pagoda are very limited. More architectural and engineering approach is need to research not only art historial understanding but also safety as a structure. We can find many technical know-how from our ancestors who made stone pagodas. 1. To reduce any deformation such as relaxation and sinking of BuJae which is caused by a heavy load, the BuJae (consist of a foundation stone and lower stereobates) should be enlarged. 2. A special construction method for connection between Myonsuk and Tangjoo was invented. This unique method is not used any longer after the Three storied Stone pagoda in Gameunsa Temple site. 3. The upper BuJae and the lower BuJae are missed each other by making a difference of Okgaesuk and Okgaebatchim in size. It is done for a distribution of perpendicular load and a prevention for relaxation of BuJae. 4. The center of gravity in the BuJae is located to the center of the stone pagoda by trimming the upper surface of the Okgaebatchim into a convex shape. The man who made stone pagodas had excellent knowledge on the engineering and techniques to understand the structure of the stone pagodas. We can confirm it as follows: the enlarged BuJae, dislocated connection between upper Bujae and lower BuJae, and moving the center of gravity close to the center of the stone pagoda.

• Korean Journal of Heritage: History & Science
• /
• v.38
• /
• pp.305-327
• /
• 2005

Although the stone pagoda in Mireuk Temple site, Iksan, Cholla Province has been collapsed long time ago, few historical record has clearly explained the reason why the pagoda was collapsed and when. The west side of the pagoda have been destroyed from top to the sixth floor and the broken or damaged stone materials have been piled up in disorder. the lower part in the west was reinforced and enclosed by a stone embankment levelled to the height of the first storey of the pagoda. With no record informing the historical fact when it was made and by whom, it is only presumed that the embankment may have been built long time ago in order to prevent remains from further destruction. In the second chapter of the study, it has been tried to restore a reasonable historical background of the pagoda based on records or comments found in literatures such as traditional poetry and essays in chronological order. The collapsed slope in the west side, just above the embankment surrounding the lower part of the pagoda, was concreted in 1915 during the Japanese colonial period. Then in 1998, the Jeollabukdo has examined the structural safety of the pagoda. The Cultural Properties Committee has decided have the concrete layer removed and moreover to take apart the whole pagoda. It is also included that the disassembled stone materials should be given proper conservation treatments before being put into the place where they were in the reassembling process. The front view of the collapsed phase of the pagoda was revealed when the concrete-covered layer was removed. A hypothesis was built that there may be as many different appearances of collapsed pagoda depending on natural causes such as earthquake, sunken foundation, flood and typhoon. In chapter three, characteristic features were classified by examining various images of pagodas destroyed by different natural reasons mentioned in historical records. The chapter four dealt with comparison and analysis on the conditions shown in the stone pagoda in Mireuk Temple site and other examples studied in advance. The result of the study revealed that though having been made higher than the ground surface, the podium or the base of the pagoda actually has been eroded by rain and water. The erosion is supposed not only to have been proceeded for a long time without break but also to have caused the first storey body stone in the west inclined to outward. It has come to a conclusion that the pagoda may have been lead to collapse when the first storey body stone, supporting the whole weight from the upper storeys, became out of upright position and lost its balance. However, no such distinctive features of structural changes shown in pagodas collapsed by natural causes like earthquake, typhoon or sunken basement, have been found in the stone pagoda in Mireuk Temple site.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.22 no.2
• /
• pp.84-87
• /
• 2018

Purpose The radiopharmaceutical used in the nuclear medicine department is used only for the specific patient according to the prescription or instruction of the doctor without selling, so it is dispensed and it is distributed and used for the examination. Radiopharmaceuticals administered to patients should be managed appropriately as well as radiation safety management during dispensation. The purpose of this study is to investigate microbial contamination during dispensation of radiopharmaceuticals Materials and Methods This study distinguished between general workbench and clean workbench and performed three tests. First, microbial cultivation test of radiopharmaceutical prepared and dispensed in general workbenches and sterile workbenches were carried out five times, respectively. The second test was performed settle plate method three times before and after the use of the exhaust filter. Finally, Adenosine Triphosphate (ATP) measurement was performed in each workbench to measure bacterial counts. In addition, ATP measurement were carried out by designating locations and items that may be contaminated during dispensation. Results In the microbial culture test, no microorganisms were detected in both samples. In the settle plate method, it was detected without using of the exhaust filter in a general workbench once. In the ATP measurement test, it was measured at the level of 400 RLU or less, which is the standard value of contamination, in both workbenches surface. In additional ATP measurement test, the refrigerator handle in the distribution room was measured above the reference value of 1217 RLU, the vacuum vial shield of the Tech Generator at 435 RLU, and the syringe holder at 1357 RLU. After environmental disinfection, the results were reduced to 311 RLU, 136 RLU, and 291 RLU. Conclusion No contamination by bacteria was found in both workbenches. However, microbial contamination may occur if the use of an exhaust filter or proper hand hygiene is not achieved. Regular inspections and management for aseptic processing themselves will be necessary.

• Journal of the Korean Society of International Agriculture
• /
• v.30 no.4
• /
• pp.257-268
• /
• 2018

Recently, the international standardization of ISO in the field of Oriental Herbal Medicine has been progressing rapidly under the direction of China's promotion. China's intention to promote international standardization is to extend its influence to the world and beyond the domestic market. The Oriental medicine system in East Asia has similar roots in academic terms, but the medicines that can be supplied and received in each country are different and have developed independently. The international standardization of medicinal herbs is expected to function in a direction that weakens such differentiation and independence. From a commercial point of view, international standardization is no different from creating evaluation criteria for oriental medicinal products, and it is expected that its potential impact on domestic and overseas markets and producers will be large. In particular, the international standardization centered on China can lead to favorable evaluation criteria for China, which may further negatively affect the market competitiveness of domestic raw materials, which have been pushed back by Chinese manufacturers. If the domestic production base is weakened, not only will the farmers suffer but the supply and demand of raw materials will also be manipulated, safety management control will be reduced, and the development of oriental herbal products using domestic raw materials will be hurt. Therefore, in the promotion of international standardization, it is necessary not only to reflect the value of Korean herbal medicine but also to provide strategic responses to protect the domestic production base. However, in the case of recent initiatives, there is no precedent in analyzing influence on the production partners and the related industries. In addition, there are few related papers and reports on the subject, so the publicity process has not been done sufficiently. In response to this, this study will examine the countermeasures against the international standardization of herbal medicines through reviewing its present status and evaluating the agenda of the Korean initiative.

• Korea Science and Art Forum
• /
• v.37 no.2
• /
• pp.219-230
• /
• 2019

According to the National Statistical Office, the number of senior citizens aged 65 or over has exceeded 7 million as of 2017, and the number of senior citizens who live alone among them exceeded 1.3 million. Most of the senior citizens who live alone suffer from absolute poverty (68.5% of them has monthly income less than 500,000 won) and they have difficulties for basic living in the blind spot of our society. In particular, the heating is quite a serious issue for the senior citizens who live alone and belong to vulnerable social group in the winter, and to make it worse, they are exposed to frequent fire accidents due to the negligence in handling electric appliances such as electric heaters and electric pads. The main reason the indoor tent products are being used by senior citizens who live alone is that it saves energy, ensures warm sleep, and improves fire safety. Following the expansion of the indoor tent market, this study focused on the idea that there is a need for an in door tent suitable for senior citizens who live alone and belong to low income bracket and intended to improve its efficiency in relation to use, resting, and storage. For this, a basic survey was conducted on the products of existing brands to analyze advantages and disadvantages and it was possible to understand the demands that consumers have for existing products. Accordingly, a survey on consumer preference was conducted using a designed model and the Zabara typp, which demonstrated the best efficiency in terms of installation convenience, space usability, and appearance design was selected. Based on the results of selection, the product design and final prototype were completed. The results and details of the study are as follows; First, factors that were not recognized in product development phase could be identified through usability survey and interview with actual users. Second, for the effective aspect of the prototype, senior citizens could install and fold the tend more easily and quickly than expected. Based on these results of this study, it is expected that not only senior citizens who live alone but also various other users can use the tent to create another comfortable private space indoors.

• Economic and Environmental Geology
• /
• v.54 no.4
• /
• pp.409-425
• /
• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Journal of Life Science
• /
• v.31 no.6
• /
• pp.603-608
• /
• 2021

The purpose of this perspective research is to discuss the potential role of exercise-interventions in COVID-19, terms of prevention and prognosis in the periods of the COVID-19 vaccine. SARCO-CoV-2. COVID-19 was detected as a new virus causing severe cardiovascular and respiratory complications. It emerged as a global public health emergency and national pandemic. It caused more than 1 million deaths in the first 6 months of the pandemic and resulted in huge social and economic fluctuations internationally. Unprecedented stressful situations, such as COVID-19 blue and COVID-19 red impact on many health problems. In healthy individuals, COVID-19 infection may induced no symptoms (i.e., asymptomatic), whereas others may experience flu-like symptoms, such as ARDS, pneumonia, and death. Poor health status, such as obesity and cardiovascular and respiratory complications, are high risk factors for COVID-19 prevention, occurrence, and prognosis. Several COVID-19 vaccines are currently in human trials. However, the efficacy and safety of COVID-19 vaccines, including potential side effects, such as anaphylaxis (a life-threatening allergic reaction) and rare blood clots, still need to be investigated. On the basis of direct and indirect evidence, it seems that regular and moderate physical exercise can be recommended as a nonpharmacological, efficient, and safe way to cope with COVID-19. Physical inactivity and metabolic abnormalities are directly associated with reduced immune responses, including reduced innate, CMI, and AMI responses. Due to prolonged viral shedding, quarantine in inactive, obese and disease people should likely be longer than physical active people. Multicomponent and systemic exercise should be considered for the obese, disease, and elderly people. More mechanism research is needed in this area.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.11 no.1
• /
• pp.35-51
• /
• 2009

Three different Cordyceps militaris(Paecilomyces tenuipes and Cordyceps militaris from grain or pupae) were analysed for their chemical composition, fatty acids composition and the concentration of amino acids, cordycepin and heavy metal to obtain basic information on them as feed supplements for livestock. The crude protein content of C. militaris from grain and pupae was 76.16 and 75.45%, respectively, being higher than that of P. tenuipes(57.21%). The concentration of linoleic acid was much higher but that of linolenic acid was much lower for C. militaris from grain than for the others. The cordycepin content was significantly higher for C. militaris from grain than for that from pupae (1.64% vs 0.68% on a DM basis). But cordycepin was not detected in P. tenuipes. Heavy metal contents(Cr, Pb, Cd, Hg) for all C. militaris were below the allowance levels recommended by Ministry of Agriculture and Forestry in Republic of Korea.

• Journal of the Korean Geotechnical Society
• /
• v.25 no.12
• /
• pp.87-105
• /
• 2009

Nonlinear dynamic deformation characteristics, expressed in terms of normalized shear modulus reduction curve (G/$G_{max}-\log\gamma$, G/$G_{max}$ curve) and damping curve (D-$\log\gamma$), are important input parameters with shear wave velocity profile ($V_s$-profile) in the seismic analysis of (new or existing) fill dam. In this paper, the reasonable and economical methods to evaluate the nonlinear dynamic deformation characteristics for core zone and rockfill zone respectively are presented. For the core zone, 111 G/$G_{max}$ curves and 98 damping curves which meet the requirements of core material were compiled and representative curves and ranges were proposed for the three ranges of confining pressure (0~100 kPa, 100 kPa~200 kPa, more than 200 kPa). The reliability of the proposed curves for the core zone were verified by comparing with the resonant column test results of two kinds of core materials. For the rockfill zone, 135 G/$G_{max}$ curves and 65 damping curves were compiled from the test results of gravelly materials using large scale testing equipments. The representative curves and ranges for G/$G_{max}$ were proposed for the three ranges of confining pressure (0~50 kPa, 50 kPa~100 kPa, more than 100 kPa) and those for damping were proposed independently of confining pressure. The reliability of the proposed curves for the rockfill zone were verified by comparing with the large scale triaxial test results of rockfill materials in the B-dam which is being constructed.