• Title/Summary/Keyword: System Property

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Effects of chromium chloride addition on coloration and mechanical properties of 3Y-TZP (크롬염화물 첨가에 따른 지르코니아 색상 및 물리적 성질 변화에 관한 연구)

  • Oh, Gye-Jeong;Seo, Yoon-Jeong;Yun, Kwi-Dug;Lim, Hyun-Pil;Park, Sang-Won;Lee, Kyung-Ku;Lim, Tae-Kwan;Lee, Doh-Jae
    • The Journal of Korean Academy of Prosthodontics
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    • v.49 no.2
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    • pp.120-127
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    • 2011
  • Purpose: The purpose of this study was to examine the effects of chromium chloride addition on coloration, mechanical property and microstructure of 3Y-TZP. Materials and methods: Chromium chloride was weighed as 0.06, 0.12, and 0.25 wt% and each measured amount was dissolved in alcohol. $ZrO_2$ powder was mixed with each of the individual slurry to prepare chromium doped zirconia specimen. The color, physical properties and microstructure were observed after the zirconia specimen were sintered at $1450^{\circ}C$. In order to evaluate the color, spectrophotometer was used to analyze the value of $L^*$, $C^*$, $a^*$ and $b^*$, after placing the specimen on a white plate, and measured according to the International Commission on Illumination (CIE) standard, Illuminant D65 and SCE system. The density was measured in the Archimedes method, while microstructures were evaluated by using the scanning electron microscopy (SEM) and XRD. Fracture toughness was calculated Vickers indentation method and indentation size was measured by using the optical microscope. The data were analyzed with 1-way ANOVA test (${\alpha}$ = 0.05). The Tukey multiple comparison test was used for post hocanalysis. Results: 1. Chromium chloride rendered zirconia a brownish color. While chromium chloride content was increased, the color of zirconia was changed from brownish to brownish-red. 2. Chromium chloride content was increased; density of the specimen was decreased. 3. More chromium chloride in the ratio showed increase size of grains. 4. But the addition of chromium chloride did not affect the crystal phase of zirconia, and all specimens showed tetragonal phase. 5. The chromium chloride in zirconia did not showed statistically significant difference in fracture toughness, but addition of 0.25 wt% showed a statistically significant difference (P<.05). Conclusion: Based on the above results, this study suggests that chromium chlorides can make colored zirconia while adding in a liquid form. The new colored zirconia showed a slight difference in color to that of the natural tooth, nevertheless this material can be used as an all ceramic core material.

Characteristics of PM2.5 and PM10 Concentration in Pusan Area (부산지역 PM2.5와 PM10의 농도 특성)

  • Kim, Sang-Youl;Cheong, Jang-Pyo;Yi, Seung-Muk
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.6
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    • pp.1159-1170
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    • 2000
  • It is necessary to improve the ambient air quality through the proper treatment and control of pollutants by designating air pollutants to regulatory ones. Especially, human took a concern for particulate matters which raised visibility reduction, public health effects and injury of property for urban areas. In order to reduce the effect of particulate matters, we need to establish proper control strategies based on the concentration characteristics of particulate matters. In this study. to evaluate the characteristics of $PM_{2.5}$ and $PM_{10}$. thirty-eight samples of $PM_{2.5}$ and $PM_{10}$ were collected at Nam-Gu sampling site where continuous air monitoring system has been operated, from May, 1999 to November, 1999, and their concentrations for the mass and anion components($Cl^-$, $NO_3{^-}$, $SO_4{^{2-}}$) were analyzed. The important conclusions obtained in this study were as followings. Total average mass concentrations of $PM_{2.5}$ and $PM_{10}$ were 35.016 and $50.293{\mu}g/m^3$ respectively. and $PM_{2.5}/PM_{10}$ ratio was calculated 0.692. Total average concentrations of anion components in $PM_{2.5}$ were $1.581(Cl^-)$, $3.690(NO_3{^-})$ and $12.825(SO_4{^{2-}}){\mu}g/m^3$ and those in $PM_{10}$ were $2.471(Cl^-)$, $5.819(NO_3{^-})$ and $14.414(SO_4{^{2-}}){\mu}g/m^3$ respectively. From the correlations analysis. the correlation coefficient between mass concentration of $PM_{2.5}$ and $PM_{10}$ was calculated as 0.945. The correlation coefficients between $PM_{2.5}$ and anion components were analyzed as $Cl^-$(0.025), $NO_3{^-}$(0.788) and $SO_4{^{2-}}$(0.500) respectively, and the correlation coefficients between $PM_{10}$ and anion components were analyzed as $Cl^-$(-0.019), $NO_3{^-}$(0.806) and $SO_4{^{2-}}$)(0.535) respectively.

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Analysis on the Effect of the Urban Park Development on Change of Urban Spatial Structures - Focused on Gentrification around Seoul Forestry Park in Seongdong-gu - (도시공원 조성이 도시공간구조 변화에 미치는 영향 분석 - 성동구 서울숲 젠트리피케이션 현상을 중심으로 -)

  • Moon, Seung-Woon;Kim, Euijune;Ku, Jin-Hyuk
    • Journal of the Korean Institute of Landscape Architecture
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    • v.45 no.2
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    • pp.76-88
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    • 2017
  • The urban park plays important roles in protecting the urban landscape and improving citizens' health, recreation, and the emotional life. Above and beyond these roles, the urban park is expected to rearrange urban spatial structures as a kind of urban system. The purpose of this paper is to identify empirically to change urban spatial structures by construction of the urban park. This study regards gentrification around the urban park as a process to change urban spatial structures. The gentrification means the regeneration and upgrading of deteriorated urban property by the middle class or commercial developers. The site of case analysis is the Seoul Forestry Park in Sungdong-gu, Seoul. The Seoul Forestry Park is regarded as a representative urban park of Seoul, and caused gentrification around park after the 2005 opening. This study operationally defines the gentrification index and the accessibility index from an urban park and offers an empirical analysis of relation among the urban park, the gentrification and urban spatial structure in a statistic district which is the minimum unit of Korean statistic data in 2000, 2005, and 2010, using Difference-in-Difference method and linear probability model. The results of this empirical study show that the Seoul Forestry Park changes urban spatial structures by gentrification. It reverses a trend of migration of gentrifiers before and after construction of the Seoul Forestry Park. It suggests urban park construction as an alternative method for urban regeneration by inducing the middle class into the inner city of Seoul.

A Study on Imposing Contribution in the Compensation for Uncontrollable Medical Malpractice during Delivery (분만관련 불가항력적 의료사고 보상제도에 있어 분담금부과에 관한 연구 -헌법재판소 2018. 4. 26. 선고 2015헌가13 사건을 중심으로-)

  • Beom, Kyung Chul
    • The Korean Society of Law and Medicine
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    • v.19 no.2
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    • pp.139-171
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    • 2018
  • The 「Act on Remedies for Injuries from Medical Malpractice and Mediation of Medical Disputes」(hereinafter referred to as 'the Act on Mediation of Medical Disputes') provides that the state should compensate the victims of medical accidents occurred irresistibly in childbirth despite that health and medical service personnel fulfilled their duty of care for their damage within the range of its budget(Article 46 of the Act on Mediation of Medical Disputes). Given that victims of medical accidents could expect demage recovery only through lawsuits thus far, this act can be said to be a groundbreaking act. However, However, as 30% of the costs for such medical accident compensation projects are borne by those who have records of childbirth among the founders of health and medical institutions (Article 21 of the Act on Mediation of Medical Disputes), there has been a question about whether doctors are held responsible despite that the accidents such as the deaths of mothers and newborn babies occurred irresistibly without doctors' fault. However, recently, the Constitutional Court ruled that 'the range of founders of health and medical institutions' and 'share ratios of finances for compensation' in Article 46 (3) of the Act on Mediation of Medical Disputes' related to the imposition of the share of costs are institutional (Constitutional Court ruling dated April 26, 2018, 2015Heonga13, hereinafter referred to as 'the ruling in the case'). Although the ruling in the case was made based on only the principle of statutory reservation and the principle of ban on comprehensive authorization, this paper added a practical judgment. This paper proved that the share of costs in this case has the nature of burden charges in pursuit of study and does not infringe on the property rights of the founders of health medical institutions even in light of the principle of proportionality because there is a legitimate reason for imposing the burden charge. The imposition of the share of costs in the system for compensation for medical accidents occurred irresistibly is against the principle of liability with fault in part. However, the medical accident compensation projects are rational a national policy for the victims of medical accidents and the medical world clearly gains some benefits from the effect to terminate medical disputes. The expansion of finances for compensation through the payments of the share of costs will reduce the suffering and misunderstanding of victims of medical accidents occurred in the process of childbirth and will be very helpful to the construction of stable treatment environments of medical workers by quickly establishing the medical accident compensation projects as such.

Dynamics of Technology Adoption in Markets Exhibiting Network Effects

  • Hur, Won-Chang
    • Asia pacific journal of information systems
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    • v.20 no.1
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    • pp.127-140
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    • 2010
  • The benefit that a consumer derives from the use of a good often depends on the number of other consumers purchasing the same goods or other compatible items. This property, which is known as network externality, is significant in many IT related industries. Over the past few decades, network externalities have been recognized in the context of physical networks such as the telephone and railroad industries. Today, as many products are provided as a form of system that consists of compatible components, the appreciation of network externality is becoming increasingly important. Network externalities have been extensively studied among economists who have been seeking to explain new phenomena resulting from rapid advancements in ICT (Information and Communication Technology). As a result of these efforts, a new body of theories for 'New Economy' has been proposed. The theoretical bottom-line argument of such theories is that technologies subject to network effects exhibit multiple equilibriums and will finally lock into a monopoly with one standard cornering the entire market. They emphasize that such "tippiness" is a typical characteristic in such networked markets, describing that multiple incompatible technologies rarely coexist and that the switch to a single, leading standard occurs suddenly. Moreover, it is argued that this standardization process is path dependent, and the ultimate outcome is unpredictable. With incomplete information about other actors' preferences, there can be excess inertia, as consumers only moderately favor the change, and hence are themselves insufficiently motivated to start the bandwagon rolling, but would get on it once it did start to roll. This startup problem can prevent the adoption of any standard at all, even if it is preferred by everyone. Conversely, excess momentum is another possible outcome, for example, if a sponsoring firm uses low prices during early periods of diffusion. The aim of this paper is to analyze the dynamics of the adoption process in markets exhibiting network effects by focusing on two factors; switching and agent heterogeneity. Switching is an important factor that should be considered in analyzing the adoption process. An agent's switching invokes switching by other adopters, which brings about a positive feedback process that can significantly complicate the adoption process. Agent heterogeneity also plays a important role in shaping the early development of the adoption process, which has a significant impact on the later development of the process. The effects of these two factors are analyzed by developing an agent-based simulation model. ABM is a computer-based simulation methodology that can offer many advantages over traditional analytical approaches. The model is designed such that agents have diverse preferences regarding technology and are allowed to switch their previous choice. The simulation results showed that the adoption processes in a market exhibiting networks effects are significantly affected by the distribution of agents and the occurrence of switching. In particular, it is found that both weak heterogeneity and strong network effects cause agents to start to switch early and this plays a role of expediting the emergence of 'lock-in.' When network effects are strong, agents are easily affected by changes in early market shares. This causes agents to switch earlier and in turn speeds up the market's tipping. The same effect is found in the case of highly homogeneous agents. When agents are highly homogeneous, the market starts to tip toward one technology rapidly, and its choice is not always consistent with the populations' initial inclination. Increased volatility and faster lock-in increase the possibility that the market will reach an unexpected outcome. The primary contribution of this study is the elucidation of the role of parameters characterizing the market in the development of the lock-in process, and identification of conditions where such unexpected outcomes happen.

Impacts of Green Manure Crop and Charcoal Applications on Ginger Growth and Soil Properties (녹비작물 및 Charcoal 처리가 생강 생육 및 토양 특성에 미치는 영향)

  • Yang, Hong-Seok;Kim, Dong-Jin;Ahn, Byung-Koo;Lee, Jin-Ho
    • Korean Journal of Organic Agriculture
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    • v.22 no.3
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    • pp.503-519
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    • 2014
  • This study was conducted to investigate ginger growth and its nutrient uptake depending on changes of soil properties as affected by applications of green manure crop and/or charcoal in continuous cropping system. The green manure crops applied were barley and hairy vetch, and charcoal was additionally treated in selected plots as a soil conditioner. Experimental plots were prepared as Plot 1 (control), Plot 2 (barley of 8kg $10a^{-1}$), Plot 3 (hairy vetch of 12kg $10a^{-1}$), Plot 4 (charcoal of 1,000kg $10a^{-1}$ and barley 8kg $10a^{-1}$), and Plot 5 (charcoal of 1,000kg $10a^{-1}$ and hairy vetch of 12kg $10a^{-1}$) with two different soil conditions (high clay content, HCC and low clay content, LCC). When comparing selected chemical properties of soils before and after cultivating ginger plant, soil pH decreased from 6.9~8.1 to 6.8~7.6, and electrical conductivity (EC) also declined from $0.45{\sim}1.25dSm^{-1}$ to $0.30{\sim}0.61dSm^{-1}$. However, the content of soil organic matter (SOM) and total nitrogen (T-N) increased. Thus, the soil chemical properties were improved with the applications of green manures and charcoal. Also, macro- and micro-nutrient contents of ginger plants in the different plots were various between normal and diseased plants grown in soils with HCC and LCC. In particular, the concentration of manganese (Mn) was 3~4 folds higher in the diseased plant than in the normal plants. Ginger growth status and yield was relatively improved with the applications of green manures and charcoal as comparing with control plot. Especially in the Plot 4 with LCC, the ginger plant was not infected by root-rot disease.

Cellular Protective Effects of Peanut Sprout Root Extracts (땅콩나물 뿌리 추출물의 세포 보호 효과)

  • Jo, Na Rae;Park, Chan Il;Park, Chae Won;Shin, Dong Han;Hwang, Yoon Chan;Kim, Yong Hyun;Park, Soo Nam
    • Applied Chemistry for Engineering
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    • v.23 no.2
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    • pp.183-189
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    • 2012
  • In this study, the cellular protective effect and antioxidative property of peanut sprout root extracts were investigated. Cellular protective effects of peanut sprout root extracts on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The ethyl acetate fraction of extracts exhibited a cellular protective effect in a concentration dependent manner. Particularly, the aglycone fraction of extracts showed prominent cellular protective effects in a concentration range (5~50 ${\mu}g/mL$). They are more effective than that of (+)-${\alpha}$-tocopherol, known as a lipid peroxidation chain blocker. Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of peanut sprout root extracts on ROS generated in $Fe^{3+}$-EDTA/$H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The ethyl acetate fraction of extracts ($OSC_{50}$; 1.59 ${\mu}g/mL$) showed a similar ROS scavenging activity compare with that of L-ascorbic acid (1.50 ${\mu}g/mL$), known as a strong antioxidant. On the other hand, the order of free radical (1,1-diphenyl-2-picrylhydraxyl, DPPH) scavenging activity ($FSC_{50}$) was (+)-${\alpha}$-tocopherol > 80% MeOH extract > aglycone fraction > ethyl acetate fraction. These results indicate that peanut sprout root extracts can function as an antioxidant in biological systems, particularly skin exposed to solar UV radiation by scavenging $^1O_2$ and other ROS, and to protect cellular membranes against ROS.

A Study on the Effect of Benefit Limit Measure on the likelihood of the late payers of paying missed health insurance premium: The Case of Korea (건강보험료 체납자에 대한 급여제한 사전통지제도의 효과성 분석)

  • Cho, Byong-Hee;Yoo, Taekyun;Yun, Seong-Won
    • Korean Journal of Social Welfare Studies
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    • v.44 no.3
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    • pp.421-450
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    • 2013
  • One of the challenging tasks of the National Health Insurance Corporation(NHIC). the only public insurance institution administrating the Korea's compulsory national health insurance(NHI) system, is to make those NHI beneficiaries who fail to make a scheduled monthly premium payment to pay. For this purpose, the NHIC has been using a measure known as 'Benefit Limit Measure(BLM)' in which those who miss premium payment for six or more month's in total are classified as 'late payer' and are sent warnings and late payer status notices. If the late payers fail to make a full payment of missed premiums even after receiving the written notices, the NHIC can order a temporary seizure of the late payer's property until all missed premiums plus interest are paid. Recently, the BLM has been criticized by the public of its cruel nature, and its effectiveness has been questioned because no empirical evidence has been collected. In this study, the authors using the NHIC data set attempted to analyze the effectiveness of the BLM. Those late payers for whom the BLM was administered were compared to those not in terms of the likelihood of paying missed premium payments with a series of logistic regression analyses models. Data analyses results showed that the likelihood of paying one or more month's unpaid premium of the former group was 14 to 46 times higher than the latter. It, however, was also found that the BLM was only effective to make no more than 12% of the late payers to pay at all. Based on the study findings, the authors made a few recommendations regarding the BLM.

Preparation of Liquid Crystal Emulsion for Transdermal Delivery of Glycyrrhizic Acid and Physical Characteristics and In Vitro Skin Permeation Studies (글리시리직애씨드의 경피 전달을 위한 액정 에멀젼의 제조와 물리적 특성 및 In Vitro 피부투과 연구)

  • Jung, Jin Woo;Yoo, Cha Young;Park, Soo Nam
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.41 no.4
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    • pp.315-324
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    • 2015
  • In this study, we prepared liquid crystal emulsion composed of amphiphilic substance $C_{14-22}$ alcohol, $C_{12-20}$ alkyl glucoside, behenyl alcohol and studied liquid crystal emulsion of properties and in vitro skin permeation. The results of formulation experiments, the clear liquid crystalline structure was observed in the ratio of $C_{14-22}$ alcohol 0.8%, $C_{12-20}$ alkyl glucoside 3.2%, behenyl alcohol 4% in the formulation. The results of physical property measurements, the viscosity of liquid crystal emulsion and O/W emulsion applied as a control group was respectively $1871.26{\sim}1.15Pa{\cdot}s$, $1768.69{\sim}1.14Pa{\cdot}s$ and the shear stress of O/W emulsion was 178.68 ~ 909.18 Pa, that of liquid crystal emulsion was 190.45 ~ 919.38 Pa. The storage modulus of O/W emulsion was 3428.53 ~ 9157.45 Pa, that of liquid crystal emulsion was 4487.82 ~ 8195.59 Pa. The tan (delta) value of O/W emulsion which means a ratio of viscosity to elasticity was 0.43 ~ 0.19, and that of liquid crystal emulsion was 0.23 ~ 0.25. The water content value on the skin for liquid crystal emulsion was significantly higher from 1 h to 6 h compared with that of O/W emulsion and the transepidermal water loss on the skin was significantly superior in skin moisture loss suppression from 30 min to 4 h compared with that of O/W emulsion. The results of skin permeation using glycyrrhizic acid, the result of skin permeation amount of liquid crystal emulsion for 24 h was $64.58{\mu}g/cm^2$, that of O/W emulsion was $37.07{\mu}g/cm^2$, that of butylene glycol solution was $41.05{\mu}g/cm^2$. Hourly permeability results, it is showed that skin penetration effect of the liquid crystal emulsion increases after 8 h. These results suggest that liquid crystal emulsions are effective for skin moisturizing effect and function as potential efficacy ingredient delivery system for the transdermal delivery.

Distribution and Behavior of Soil CO2 in Pohang area: Baseline Survey and Preliminary Interpretation in a Candidate Geological CO2 Storage Site (포항 지역 토양 CO2의 분포 및 거동 특성 연구: CO2 지중저장 부지 자연 배경 조사 및 예비 해석)

  • Park, Jinyoung;Sung, Ki-Sung;Yu, Soonyoung;Chae, Gitak;Lee, Sein;Yum, Byoung-Woo;Park, Kwon Gyu;Kim, Jeong-Chan
    • Journal of Soil and Groundwater Environment
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    • v.21 no.1
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    • pp.49-60
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    • 2016
  • Distribution and behavior of baseline soil CO2 were investigated in a candidate geologic CO2 storage site in Pohang, with measuring CO2 concentrations and carbon isotopes in the vadose zone as well as CO2 fluxes and concentrations through ground surface. This investigation aimed to assess the baseline CO2 levels and to build the CO2 monitoring system before injecting CO2. The gas in the vadose zone was collected using a peristaltic pump from the depth of 60 cm below ground surface, and stored at gas bags. Then the gas components (CO2, O2, N2, CH4) and δ13CCO2 were analyzed using GC and CRDS (cavity ringdown spectroscopy) respectively in laboratory. CO2 fluxes and CO2 concentrations through ground surface were measured using Li-COR in field. In result, the median of the CO2 concentrations in the vadose zone was about 3,000 ppm, and the δ13CCO2 were in the wide range between −36.9‰ and −10.6‰. The results imply that the fate of CO2 in the vadose zone was affected by soil property and vegetations. CO2 in sandy or loamy soils originated from the respiration of microorganisms and the decomposition of C3 plants. In gravel areas, the CO2 concentrations decreased while the δ13CCO2 increased because of the mixing with the atmospheric gas. In addition, the relation between O2 and CO2, N2, and the relation between N2/O2 and CO2 implied that the gases in the vadose zone dissolved in the infiltrating precipitation or the soil moisture. The median CO2 flux through ground surface was 2.9 g/m2/d which is lower than the reported soil CO2 fluxes in areas with temperate climates. CO2 fluxes measured in sandy and loamy soil areas were higher (median 5.2 g/m2/d) than those in gravel areas (2.6 g/m2/d). The relationships between CO2 fluxes and concentrations suggested that the transport of CO2 from the vadose zone to ground surface was dominated by diffusion in the study area. In gravel areas, the mixing with atmospheric gases was significant. Based on this study result, a soil monitoring procedure has been established for a candidate geologic CO2 storage site. Also, this study result provides ideas for innovating soil monitoring technologies.