• Journal of the Korean Geotechnical Society
• /
• v.16 no.4
• /
• pp.95-105
• /
• 2000

Anisotropy of stiffiness, from extremely small strains to post-failure strains, of isotropically consolidated air-pulviated sands in plane strain compression was studied by using the newly developed instrumentation for small strain measurements. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. Stress-strain relationships for a wide range of strain from about 0.0001% to 10% were obtained with measuring axial and lateral strains locally free from the effects of bedding and membrane penetration errors at the specimen boundaries. It was found that the maximum shear modulus Gmax was irrespective of the angle $\delta$of the $\sigma$1 direction relative to the bedding plane. However, the normalized Gmax was varied with the types of sand. Furthermore, the dependency of the strain and stress level on the stiffness increased as decreased.

• Geotechnical Engineering
• /
• v.14 no.4
• /
• pp.33-46
• /
• 1998

Anisotropy of stiffness, from extremely small strains to post-failure strains, of isotropically consolidated air-pluviated sands in plane strain compression was studied by using the newly developed instrumentation for small strain measurements. Seven types of sand of the world-wide origins were tested, which have been extensively used for research purposes. Stress-strain at the specimen boundaries. It was found that the maximum Young's modulus $E_{max}$ was irrespective of the angle $\delta$ of the $\delta_1$ direction relative to the bedding plane. However, the normalized$ E_{max}$ was varied with the types of sand. Furthermore, the dependency of the strain and stress level on the stiffness was increased as $\delta$ decreased.

• Polymer(Korea)
• /
• v.31 no.5
• /
• pp.369-373
• /
• 2007

In this study, solvent-free pressure sensitive adhesives (PSA) using acrylic copolymer was prepared by UV radiation to investigate the effect of comonomer on the adhesion properties. Adhesive force value of PSA was increased with the amount of comonomer having shorter side chain due to the enhanced intrinsic surface energy. Peel and shear strength were also influenced by chemical properties of comonomer. The addition of comonomer, ethyl and n-butyl acrylate allows PSA sample with high peel and shear strength. This nay be explained in terms of correlation between loss modulus and glass transition temperature of PSA. As the addition of acrylic comonomers with long side chain length decreases the loss modulus of PSA, the deformation of PSA can not be inhibited.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.45 no.5
• /
• pp.409-416
• /
• 2017

In order that multiple wideband RF transmitters which have mission to deliver essential information to aircraft operate at the same time, RF transmitter has a variable sub-carrier frequency to modulate the signal. In case of exposure to weak environment, Wide-band RF transmitter is designed to check component of transmitter that includes antenna BIT to increase system reliability. Normally, Antenna BIT measure the reflection RF power of antenna to check system condition. However, Antenna BIT has a difference that depends on testing frequency to use the long RF cable which is located between the power amp and the antenna. The periodic phenomenon of the reflected antenna power are theoretically explained about dependence on the RF cable length. Based on presented result, suggested measurement methods is effectively able to be applied to diagnosis system condition.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.50 no.2
• /
• pp.131-141
• /
• 2023

Dental caries is a multifactorial disease influenced by interactions between teeth, biofilm, dietary factors, and various biological, behavioral, sociocultural, and genetic factors. Recent research has shown that dental caries results from dysbiosis, an imbalance in the oral microbial community, shifting the concept from an infectious disease to a non-communicable disease (NCD). Dental caries shares similarities with other chronic NCDs such as cardiovascular diseases and diabetes, as they all relate to dietary intake, lifestyle habits, and environmental factors. Considering the high prevalence of dental caries and its impact on people's health and quality of life, it is important to understand dental caries as an NCD and develop effective oral health management strategies. Ecological prevention methods and efficient public health policies should be provided to reduce risk factors associated with dental caries.

• The Korean Journal of Ecology
• /
• v.25 no.5
• /
• pp.283-295
• /
• 2002

The number of species and individvals of birds observed in Bibong, Chinju-castle, Nosan and Saho parks were 49 and 4,349, 46 and 6,453, 37 and 2,817, and 33 and 6,014, nespectively The dominant species in all survey areas were shown in the order of Passer montanus(21.8%), Aegithalos spp.(20.7%), Pica pica(8.7%), Hypsipetes amaurotis(7.6%), Parus major(6.4%), Carduelis spp.(4.6%). Migration of birds was the order of residents, summer visitor, winter visitor, and passage migrant. The number of bird species appeared was the fewest in winter as 40 species and the most in spring as 53 species. Species diversity was the highest in Bibong park as 1.3256 and followed in the order of Sanho park, Nosan park, and Chinju-castle park. The nesting guild was higher at outside and artificial nesting guild(7-15 species) compared with hole, canopy, bush nesting guild(1-7 species) in all survey areas. The breeding forage guild was higher at canopy and bush(12-25 species) than that at outside, artificial, and air forage guild(2-8 species).

• Korean journal of communication and information
• /
• v.84
• /
• pp.152-188
• /
• 2017

This study stereotyped the media on the basis of ideological inclinations and media types and explored the news coverage through word analysis, network analysis, and frame analysis. There was no difference between conservative media and progressive media in terms of the amount of news. The conservative mainstream media considered the THAAD rumor as an unnecessary misunderstanding and a rumor based conflict of the south-south. The progressive mainstream media mentioned much about Hwang Gyoan, external influences, and lies and highlighted the government's opinion that there was external influence that spread a vicious rumor. Conservative media mentioned on the bringing about social disturbance and in case of progressive media mentioned social disturbance, and progressive media mentioned the responsibility of government and the attitude of conservative media about the diffusion of the rumor. In conclusion the press framed the THAAD rumor on the basis of their ideological inclinations instead of the role of journalist.

• Elastomers and Composites
• /
• v.37 no.1
• /
• pp.21-30
• /
• 2002

Core-shell polymers of methyl methacrylate/styrene pair were prepared by sequential emulsion polymerization in the presence of sodium dodecyl benzene sulfonate(SDBS) as an emulsifier using ammonium persulfate(APS) as an initiator. The characteristics of these core-shell polymers were evaluated. Core-shell composite latex has the both properties of core and shell components in a particle, where as polymer blonds or copolymers show a combined properties from the physical properties or two homopolymers. This unique behavior of core-shell composite latex can be used in many industrial fields. However, in preparation of core-shell composite latex, several unexpected phenomina are observed, such as, particle coagulation, low degree of polymerization, and formation of new particles during shell polymerization. To solve the disadvantages, we studied the effects of surfactant concentrations, initiator concentrations, and reaction temperature on the tore-shell structure or PMMA/PSt and PSt/PMMA. Particle size and particle size distribution were measured by using particle size analyzer, and the morphology of the core-shell composite latex was observed by using transmission electron microscope. Glass transition temperature($T_g$) was also measured by using differential scanning calorimeter. To identify the core-shell structure, pH of the composite latex solutions were measured.

• The Korean Society of Law and Medicine
• /
• v.16 no.2
• /
• pp.55-84
• /
• 2015

The tuberculosis is the infectious disease. Generally, the active tuberculosis patient can infect the 10 persons for one year within the daily activities like casual conversation and singing together. The infectivity of tuberculosis can continue for a life time, and infected persons can remain at risk for developing active tuberculosis. To control this contagious disease, along with the active tuberculosis patients, non-infectious but non-compliant patients who can be infectious if their immune systems become impaired have to be managed. To control the non-complaint patients, medical treatment order should be combined with the public order. Because tuberculosis is the risk of community health, the human rights like liberty and freedom of movement can be restricted for public welfare under the article 37(2) of constitution. Even when such restriction is imposed, no essential aspect of the freedom or right shall be violated. The degree of restriction on the rights of citizens is different what methods are chosen to non-complaint patients. For example, under the directly observed therapy program, the patients and medical staffs make an appointment and meet to confirm the drug intakes according to the schedule, which is the medical treatment combined with the mildest public order. If the patients break the appointments or have the history of disobedient, the involuntary detention can obtain the legitimate cause. The Tuberculosis Prevention Act has the two step programs on this involuntary detention, The admission order (Article 15) is issued when the patients are infectious. The quarantine order (Artle 15-2) is issued when the patients are infectious and non-complaint. The legal criteria for involuntary detention are discussed and published through the international conventions and covenants. For example, World Health Organization had made guidance on human rights and involuntary detention for tuberculosis control. The restrictions should be carried out in accordance with the our law and in the legitimate objective of public interest. And the restriction should be based on scientific evidence and not imposed in an unreasonable or discriminatory manner. We define and adopt these international criteria under our constitution and legal system. Least restrictive alternative principle, proportionality principle and the individual evaluation methods are explained through the reviews of United States court decisions. Habeas Corpus Act is reviewed and adopted as the procedural due process to protect the patient rights as a citizen. Along with that, what conditions and facilities which are needed to performed quarantine order are discussed.

• Economic and Environmental Geology
• /
• v.44 no.5
• /
• pp.443-449
• /
• 2011

In this study, we carried out a survey on the degree of recognition for the brand of the Korea Institute of Geoscience and Mineral Resources (KIGAM) to contribute to reestablishing the status and role of KIGAM as an institution that people proud of by effectively delivering KIGAM's various research activities and achievements to people. About 49.9% of external publics recognized that there was relevance between research achievements of geo-technology and national brand. On the contribution of research achievements of geo-technology to promoting Korea's power of science and technology, 42.3% gave positive answers. On research achievements of mineral resources technology, just 14.4% replied they saw such results. As alternatives to promote the degree of recognition for brand, we suggested development of beneficial message, operation of brand management committee, promotion of involvement of research achievements of mineral resources technology about people-friendly subjects, development and distribution of "board game for education on mineral resources technology" for youths, activation of location PR, activation of online Q&A bulletin board, finding out star researchers, and president's PI activities.