• Journal of Korea Water Resources Association
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• v.55 no.9
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• pp.701-705
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• 2022

Reliable drought inflow scenarios are required to plan reservoirs in response to the present severe drought-like conditions. However, the previously developed method for generating drought inflows, the K-water cumulative difference method (KCM), is considered inadequate owing to its potential for negative inflow, reversal phenomena, and overestimation. Nevertheless, the occurrence of these aspects has not been theoretically analyzed. Hence, this study employed the quantile function and frequency factor for log-normal and Gumbel distributions to quantify the contributing factors of these limitations. Consequently, it was found that the negative inflows are generated when the difference in the location parameters, during the accumulation process, exceeds that of the scale parameters. In addition, as the standard deviation decrease during the accumulation process, the reversal phenomena, and inflated values prevailed.

• Journal of the Optical Society of Korea
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• v.1 no.2
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• pp.74-80
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• 1997

300mm F/4.0 telephotolens with diffractive hybrid lens was designed, and its optical performance was tested and compared with a traditional lens system. DOE(Diffractive Optical Element) reconstructs wavefronts using wave phenomena of light to focus the incident light onto the focal point and has negative Abbe number while a traditional lens uses geometrical phenomena of light and has positive Abbe number. Therefore, a diffractive hybrid lens containing both refractive and diffractive elements can remarkably correct chromatic aberration and spherical aberration of an optical system. We investigated and analyzed the optical properties of a diffractive hybrid lens for the visible spectrum, and we used a difractive hybrid lens to design and evaluate a 300mm F/4.0 telephotolens without the special LD(Low Dispersive) glass lens which is costly and difficult to manufacture. Most traditional telephotolenses use the special LD glass for chromatic aberration correcton. Optical performance tests such as resolution and characteristics of aberration of both lens systems using a diffractive hybrid lens and traditional lens were performed.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.212-214
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• 2012

Both the electrically positive and negative particles in a cell of quick response-liquid powder display (QR-LPD) are surrounded by conductive electrodes on the upper and lower substrate and the dielectric materials of the barrier ribs. Particles in a cell are attached to or detached from the other materials by image force, electric field, Coulomb's force, and Van der Waals' force. Through these forces, the moving particles form an image but induce clumping phenomena. Particles having a large kinetic energy by a large q/m value crash into the opposite electrode with high speed at a large driving voltage and quickly lose electrically charged material. As a result, these particles are clumped and degrade panel performance. The clumped particles in a cell are observed by microscopic photographs and ascertained by a response time. When the bias voltage is increased to 0.68-0.76 $V/{\mu}m$, particle clumping occurs abruptly and the response time increases sharply. This particle clumping is similarly observed after the number of driving times at the driving voltage (0.42-0.64 $V/{\mu}m$).

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.78-78
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• 2015

Metamaterials, artificially structured nanomaterials, have enabled unprecedented phenomena such as invisibility cloaking and negative refraction. Especially, hyperbolic metamaterials also known as indefinite metamaterials have unique dispersion relation where the principal components of its permittivity tensors are not all with the same signs and magnitudes. Such extraordinary dispersion relation results in hyperbolic dispersion relations which lead to a number of interesting phenomena, such as super-resolution effect which transfers evanescent waves to propagating waves at its interface with normal materials and, the propagation of electromagnetic waves with very large wavevectors comparing they are evanescent waves and thus decay quickly in natural materials. In this abstract, I will focus discussing our efforts in achieving the unique optical property overcoming diffraction limit to achieve several extraordinary metamaterials and metadevices demonstration. First, I will present super-resolution imaging device called "hyperlens", which is the first experimental demonstration of near- to far-field imaging at visible light with resolution beyond the diffraction limit in two lateral dimensions. Second, I will show another unique application of metamaterials for miniaturizing optical cavity, a key component to make lasers, into the nanoscale for the first time. It shows the cavity array which successfully captured light in 20nm dimension and show very high figure of merit experimentally. Last, I will discuss the future direction of the hyperbolic metamaterial and outlook for the practical applications. I believe our efforts in sub-wavelength metamaterials having such extraordinary optical properties will lead to further advanced nanophotonics and nanooptics research.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9557-9565
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• 2014

MiRNAs are endogenous, single stranded ~22-nucleotide non-coding RNAs (ncRNAs) which are transcribed by RNA polymerase II and mediate negative post-transcriptional gene regulation through binding to 3'untranslated regions (UTR), possibly open reading frames (ORFs) or 5'UTRs of target mRNAs. MiRNAs are involved in the normal physiology of eukaryotic cells, so dysregulation may be associated with diseases like cancer, and neurodegenerative, heart and other disorders. Among all cancers, lung cancer, with high incidence and mortality worldwide, is classified into two main groups: non-small cell lung cancer and small cell lung cancer. Recent promising studies suggest that gene expression profiles and miRNA signatures could be a useful step in a noninvasive, low-cost and repeatable screening process of lung cancer. Similarly, every stage of lung development during fetal life is associated with specific miRNAs. Since lung development and lung cancer phenomena share the same physiological, biological and molecular processes like cell proliferation, development and shared mRNA or expression regulation pathways, and according to data adopted from various studies, they may have partially shared miRNA signature. Thus, focusing on lung cancer in relation to lung development in miRNA studies might provide clues for lung cancer diagnosis and prognosis.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.37-41
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• 2004

Quenching phenomena is one of major concern in development of millimeter or sub-millimeter scale micro combustor for the size of the combustor is near extinction condition. In this work we focused on the effect of combustor wall condition that was parameterized by Perovskite LSC($La_{0.8}$$Sr_{0.2}$$CoO_3$) redox catalyst. The experiment was done by variable gap-width 2D wall equipment. The flame was produced by premixed methane-air jet issuing from millimeter-scale slot burner and it propagated through the narrow gap of the walls. By comparison of flame behaviour near catalyst-coated wall and simple glass wall, we investigated the effect of possible surface reaction on quenching phenomena. The flame between two plates was observed where the gap of the plates was reduced stepwise from 20mm to a distance of quenching occurrence. The two flames with and without surface modification were almost same by observation. But the gap for the occurrence of quenching was increased between catalyst-coated wall. So we concluded that surface reaction close to combustor wall has a negative effect on micro combustion.

• Child Health Nursing Research
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• v.10 no.1
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• pp.117-125
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• 2004

Purpose: The research was conducted to investigate the experience of maternal role attainment of mothers of premature infants admitted in NICU and to conceptualize the phenomena. Method: The grounded theory method was utilized for data collection and analysis. 8 mothers of premature infants were selected and in-depth interview was performed. Paradigm model was utilized for data analysis and presentation. Result: The central category was 'unstable maternal identity'. The properties of the core phenomena was 'ambivalent feeling to baby' 'negative emotion' 'commitment to baby'. The loss of control due to premature delivery was the causal condition. contextual condition was the 'perceived threats' due to severity of the premature infant and uncerainty of the baby's life. The mother's health status, economic status, and familial and social support was recognized as intervening conditions during the process of maternal role attainment. The strategic action/interactions were emotion-focused coping, reappraisal of the situation, problem-focused coping, and information seeking. The consequence was the maternal role attainment with competence and expectation. Conclusion: The process of maternal role attainment was affected by threats due to severity of the baby and intervening factors and interaction strategy. Further research is recommended to develop adequate intervention method during the process of maternal role attainment.

• Journal of Distribution Science
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• v.19 no.12
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• pp.91-101
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• 2021

Purpose: This study aims to explore the effects of government's value intervention messages on the prevention and control of infectious disease in the risk communication process in terms of goveremnt policy response to COVID-19 from the mismatch message perspective, and draws the relevant implicaitons. Due to the infeciton spread, some people point out that depression caused by COVID-19 is because of wrong signals of the government and infectious disease prevention and control authorities, namely value intervention messsages. Research design, data and methodology: This study examined the epidcmic situation through message deails regarding the effects of government's mismatch messages on prevention and control of infectious disease and the resulting phenomena. Results: People's lives are under serious threat overall, so the declaration of the end of COVID-19 is almost impossible unlike MERS. Economic downturn due to foreced prevention and control regulaitons of COVID-19, mistruct of social distancing, fatigue on mismatch messages, and moral hazard on the awareness of prevention and control of infectious disease are negative phenomena to risk communiaiton on COVID-19. Conclusions: This study investigated the government authorities' policy sending wrong signals due to mismatching of the reality at this point in time for infectious disease prevention and control from the risk communicaiton perspectrive.

• Journal of Physiology & Pathology in Korean Medicine
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• v.28 no.5
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• pp.465-477
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• 2014

In Korean Medicine (KM), the Yin-Yang doctrine is still used as a theoretical tool for understanding and explaining the clinical experiences. However, as the traditional culture declined in East Asia and the scientific culture took over, there was an increased negative view on the Yin-Yang doctrine, and thus a heightened distrust over KM. For KM to survive in an unfamiliar culture of science, a novel outlook on the Yin-Yang doctrine is needed. In this sense, I consider a thoroughly medical take on the Yin-Yang doctrine to be most important. The focus needs to be on the goals of medicine: this includes riddance of any discourses on Yin-Yang that cannot contribute to the goals, and an enhancement of the Yin-Yang concept as a rational and scientific terminology. One way to achieve this is by understanding Yin-Yang as a type of metaphor. The Yin-Yang doctrine that is utilized in KM corresponds well to the conceptual metaphor suggested by Lakoff and Johnson. As a metaphor, the Yin-Yang concept plays a role in structuring the target domain, that is life phenomena, metaphorically. Through the Yin-Yang metaphors, the life phenomena are understood as the Yin-Yang phenomena, and are systematically organized by the subcategories contained in the Yin-Yang doctrine. Understanding Yin-Yang as a metaphor is a good way to enhance the Yin-Yang concept and doctrine as a rational terminology and method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.12
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• pp.1161-1169
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• 2012

A numerical study has been conducted to investigate the aerodynamic characteristics and behavior of a wing-tip vortex around a three-dimensional symmetric wing (NACA0015) in the vicinity of the ground. The aerodynamic characteristics and the wing-tip vortex change as a wing approaches the ground as a result of two different phenomena: the ground effect and the Venturi effect. The ground effect increases lift and decreases drag whereas the Venturi effect generates negative lift and increases drag suddenly. A symmetric airfoil experiences both phenomena with respect to changes in the angle of attack. In the case of a NACA0015 airfoil, the Venturi effect is dominant at small angles of attack but the ground effect is dominant at large angles of attack. Interestingly, both phenomena can be observed at the 4 degree of angle of attack. The vortex core moves inside a wing when the wing experiences the Venturi effect, whereas the vortex core moves outward when the wing experiences the ground effect.