• Journal of Korean Medical classics
• /
• v.29 no.3
• /
• pp.1-12
• /
• 2016

Objectives : Deciding whether a year will be a Normal Qi Year is an important task within the study of Five Periods. Normal Qi Year, a period of peace and calmness, comes when a given year's elements are neither excessive nor deficient. There is, however, no unified definition for Normal Qi Year. This paper is written to propose a definition that could serve as such. Methods : Somunyukgihyunjumileo, various masters' opinions, and conventional Chinese scholars' claims were studied based on Hwnagjenaegyeong to produce this paper. Results : Within The Year of Sehoi(歲會年), only four years are Normal Qi Years and the other four years are not Normal Qi Years. The six years of Jehwa(齊化) are all Normal Qi Years because excessive elements are suppressed. The six years of Donghwa are all Normal Qi Years because deficient elements are bolstered. The years of Dongsehoi (同歲會) are all Normal Qi Years. All of the six elemental deficient years of the Year of Sunhwa(順化年), when the energy of Heaven emanates elements, are all Normal Qi Years. Conclusions : Not counting the overlapping Normal Qi Years during a periodical circle of 60 years, there is a total of 23 Normal Qi Years: the years of Eulchuk(乙丑), Jeongmyo(丁卯), Mujin(戊辰), Gyeongo(庚午), Shinmi(辛未), Gyeyu(癸酉), Eulyu(乙酉), Jeonghe(丁亥), Gichuk(己丑), Gyeongin(庚寅), Shimnyo(辛卯), Gyesa(癸巳), Eulmi(乙未), Musul(戊戌), Gyeongja(庚子), Shinchuk(辛丑), Gyemyo(癸卯), Eulmyo(乙卯), Jeongsa(丁巳), Gimi(己未), Gyeongshin(庚申), Shinyu(辛酉), and Gyehye(癸亥).

• Journal of Theoretical and Applied Mechanics
• /
• v.2 no.1
• /
• pp.51-70
• /
• 1996

This study is generalization of the study of Miles[Physica 11D, 1984, pp.309-323]on the resonant motion of a spherical pendulum, which is equivalent to a particle on a spherical container subject to a linear, horizontal excitation. This study covers an arbitrary shape of container and a more general excitation (horizontal but elliptic motion). The averaging method is applied to reduce the governing equations to an autonomous system with cubic nonlinear terms, under the assumption of small amplitude of the container motion. It is shown that both the container shape and the excitation pattern affect the particle dynamics. Under the linear excitation, the anharmonic motion of the particle is possible only for a certain finite range of the parameter a controling the container shape. Stability of the particle's harmonic motion is also influenced by the excitation pattern; as the excitation trajectory becomes closer to a circle, the particle's motion has a stronger tendency to become stable and to follow the rotational direction of the excitation. Under a circular excitation, the motion is always stable and circular with the same rotational direction as the excitation. Analogy between the present model and that of the surface wave inside a circular is studied quantitatively.

• Journal of the Korean Ceramic Society
• /
• v.42 no.11 s.282
• /
• pp.758-762
• /
• 2005

Gas valve for domestic use is used for flow control of LPG (Liquefied Petroleum Gas) or LNG (Liquefied Natural Gas) of which pressure is about $200\;mmH_{2}O(\fallingdotseq0.0196\;[bar])$. Currently, two kinds of valves such as rotary type and button type are widely used in many applications. But, these valves have some problems that they are not controllable and reliable. Piezo actuation combined with modem microelectronics provides a reliable, quiet, low energy, infinitely adjustable gas valve. In this paper, gas valve using piezo actuator which are bimorph and a circle type was studied. Also, Prototype for gas valve was manufactured and characteristics of the prototype gas valve were analyzed.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.10 s.253
• /
• pp.1314-1319
• /
• 2006

This paper describes the novel fabrication method of the high-aspect-ratio nano structure which is impossible by conventional method using a shadow mask and a Deep X-ray Lithography (DXRL). The shadow mask with $1{\mu}m-sized$ apertures is fabricated on the silicon membrane using a conventional UV-lithography. The size of aperture is reduced to 200nm by accumulated low stress silicon nitride using a LPCVD (low pressure chemical vapor deposition) process. The X-ray mask is fabricated by depositing absorber layer (Au, $3{\mu}m$) on the back side of nano shadow mask. The thickness of an absorber layer must deposit dozens micrometers to obtain contrast more than 100 for a conventional DXRL process. The thickness of $3{\mu}m-absorber$ layer can get sufficient contrast using a central beam stop method, blocking high energy X-rays. The nano circle and nano line, 200nm in diameter in width, respectively, were demonstrated 700nm in height with a negative photoresist of SU-8.

• Journal of Families and Better Life
• /
• v.29 no.4
• /
• pp.17-33
• /
• 2011

The purpose of this study was to investigate diversity in the situations of multicultural families regarding the education of their children and to suggest rational ways of educating children in multicultural families. The participants in this study were 16 mothers from multicultural families typically characterized by an international marriage in which a Korean male had married a non-Korean female. The data were collected using intensive interviews over a course of three months and were analyzed by grounded theory. The results of this study showed that the participants had difficulty in adapting to the styles of educating children in Korean families and that they could not help their children do homework by themselves due to the limited personal relationships, the shortage of information about educating children, and an lack of organized education programs on Korean culture and history. Thus, they solved these problems by depending on different extracurricular activities and thus incurred a financial burden to support these activities. This led to excessive amounts of time and energy to earn the money to support the activities, which gave them few opportunities to acquire information on educating children by, for example, meeting with others. This explained their dependency on different extracurricular activities so as to solve the problem of their educating children. In an effort to seek ways to break this vicious circle, this study emphasized that policies related to educating children in multicultural families should focus on helping multicultural families strengthen their abilities to educate their children fundamentally.

• Geomechanics and Engineering
• /
• v.20 no.3
• /
• pp.175-189
• /
• 2020

A set of relatively simple five local shear and tension failure variables is presented and then implemented into a generalized poroelastic hydromechanical numerical model to analyze failure potential and stability of variably saturated geologic media. These five local shear and tension failure variables are formulated from geometrical relationships between the Mohr circle and the Mohr-Coulomb failure criterion superimposed with the tension cutoff, which approximate together the Mohr effective stress failure envelope. Finally, fully coupled groundwater flow and land deformation in two variably saturated geologic media, which are associated with a slope (Case 1) and a tunnel (Case 2), respectively, and their failure potential and stability are simulated using the resultant hydromechanical numerical model. The numerical simulation results of both cases show that shear and tension failure potential and stability of variably saturated geologic media can be analyzed numerically simply and efficiently and even better by using the five local shear and tension failure variables as a set than by using the conventional factors of safety against shear and tension failures only.

• Journal of Environmental Impact Assessment
• /
• v.13 no.4
• /
• pp.165-185
• /
• 2004

Assessment in Socio-economic items should be used to estimate social influence when policies and projects were introduced. To estimate current situation of socio-economic items 19 Environmental Impact Statement (EIS) of large scale projects were analyzed. The projects were selected based on magnitude of social impact when the projects were implemented. Environmental Impact Statement was categorized into line projects(road construction, railroad construction, stream development, etc), and surface projects(energy development, wetland reclamation, recreation and sport development, and housing and residential development, etc) thus being chosen for 19 projects in each categories. This report was based on the analysis of 7 items in socio-economic environmental items(i.e., population, residents, industry, public facilities, education, transport and historical monument). Most EIS did not follow the regulation suggested by Ministry of Environment, and only current circumstances were briefly described. Indifference of in-depth analysis of socioeconomic environmental items would influence the process of social and environment impact negatively in the midst of construction of National Projects such as Outer Circle Seoul Highways, Saemankeum Reclamation Projects, etc. This abrupt halt of construction was mostly based on a lack of public hearing or public participation. Socio-economic items are also very much lacking in quantitative method and strengthening socio-economic environmental items is needed via checklist or matrix that brings decision-makers better ideas objectively.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.31 no.3
• /
• pp.107-113
• /
• 2003

Ecological control can contribute to the sustainibility of vegetation management systems by reducing the input currently derived from non-renewable fossil energy sources. The use of turfgrass mixtures is an important tool in turf management. Turfgrass mixtures of two or more compatible and adapted species provide improved tolerance to pest and environmental stress, more so than monostands. The objectives of this study were to evaluated turf insects, pests and zoysia large patch control by turgrass mixtures. In April 2001 and 2002, plots were inoculated with 50g of Rhizoctonia solani AG2-2LP inoculum. Inoculum were treated within a 29cm diamater circle at Zoysia japonica, Zoysia japonica, Poa pratenis, or Festuca arundinacea mixtures. After four weeks, disease severity in each plot was determined. plot area visual ratings were assessed visually on a linera 0 to 100%. In August 2001 and October 2002, turf insects and pests in each plot were investigated in 10cm deep soil cores with 8cm diameters using hole cut. Zoysia large patch affected zoysiagrass monostands more severly than zoysiagrass and cool-season turfgrasses mixtures. It was suggested that the barrier effect of cool-season turfgrass suppressed zoysia large patch in the mixture of zoysiagrass and cool-season turfgrasses. Also, warm-season and cool-season turfgrasses mixtures suppressed insect populations more efficiently than warm-season turfgrass monostands.

• Current Optics and Photonics
• /
• v.5 no.2
• /
• pp.164-172
• /
• 2021

In this paper a catadioptric laser-irradiation-precision test system is designed, to achieve a high-precision laser-irradiation-accuracy test. In this system, we adopt the method of imaging the entire target surface at a certain distance to realize the measurement of laser-irradiation precision. The method possesses the advantages of convenient operation, high sensitivity, and good stability. To meet the test accuracy requirement of 100 mm/km (0.01%), the coma, field curvature, and distortion over the entire field of view should be eliminated from the optical system's design. Taking into account the whole length of the tube and the influence of stray light on the structure type, a catadioptric system with a hood added near the primary imaging surface is designed. After optimization using the ZEMAX software, the modulation transfer function (MTF) of the designed optical system is 0.6 at 30 lp/mm, the full-field-of-view distortion is better than 0.18%, and the energy concentration in the 10-㎛-radius surrounding circle reaches about 90%. The illumination-accuracy test results show that the measurement accuracy of the radiation hit rate is better than 50 mm when the test distance is 1 km, which is better than the requirement of 100 mm/km for the laser-irradiation-accuracy test.

• Coupled systems mechanics
• /
• v.12 no.2
• /
• pp.127-149
• /
• 2023

A theoretical method is developed to analyze the free vibration of an elastic annular plate in contact with an ideal liquid. The displacement potential functions of the contained liquid are expressed as a combination of the Bessel functions that satisfy the Laplace equation and the liquid boundary conditions. The compatibility condition along the interface between the annular plate and the contained liquid is taken into account to consider the fluid-structure coupling. The dynamic displacement of the wet annular plate is assumed to be a combination of dry eigenfunctions, allowing for prediction of the natural frequencies using the Rayleigh-Ritz method. The study investigates the effect of radial liquid boundary conditions on the natural frequencies of the wet annular plate, considering four types of liquid bounding: outer container bounded, outer and inner bounded, inner bounded, and radially unbounded. The proposed theoretical method is validated by comparing the predicted wet natural frequencies with those obtained from finite element analysis, showing excellent accuracy. The results indicate that the radial liquid bounding effect on the natural frequencies is negligible for the axisymmetric vibrational mode, but relatively significant for the mode with one nodal diameter (n =1) and no nodal circle (m' = 0). Furthermore, the study reveals that the wet natural frequencies are the largest for the plate with an inner bounded cylinder among the radial liquid boundary cases, regardless of the vibration mode.