A two-phase flow in mini-channels is consist with various flow regimes (such as bubble slug, annular, churn flow) according to gas and liquid phase flow rates. A previous researches revealed that in a case of slug flow in hydrophobic mini-channels, gas and liquid phase are perfectly separated by interfaces and triple contact line. In this study, the single dry slug flow experiments in circular mini-channel (D = 1.018 mm) are conducted to observe interfacial break-up phenomena in high capillary number range (Ca < 0.02). The slug is consist with D.I. water or D.I. water-ethanol binary mixtures (5% and 10%, mole fraction). On the base of previous researches, we calculate the pressure drop at moving triple contact line. In an addition, a single dry slug flow is visualized by using high-speed camera. Through the experiment, three regimes of pressure drop are observed; steady, loss, separation. As a result, criteria between steady and loss regimes is closely related to capillary number, and criteria between loss and separation regimes is related to surface tension.

본 연구는 헤테로코어 광파이버 센서를 활용하여 콘크리트 내부에서 발생되는 변형률의 측정을 통해 콘크리트의 프리스트레스를 직접 평가할 수 있는 새로운 매립형 센서모듈 개발을 최종 목표로 하고 있다. 이를 위하여 노출형 센서모듈을 이용한 성능발현 실험결과는 가력속도 0.12, 1.80mm/min일 때 52.1, 2.6sec로 최대 약 19배의 계측 지연현상이 발생하였다. 계측 지연현상은 구조물의 실시간 변화 상태를 계측하지 못하는 경우로 실시간 계측이 가능한 센서모듈의 개발을 위해서 추가실험이 필요한 것으로 판단하였다. 계측 지연현상 원인규명 실험은 3가지의 실험을 계획하였으며, 실험결과는 마찰저항에 의한 계측 지연이 지배적으로 확인되었다. 마찰이 제거된 장치를 이용한 센서모듈의 실험결과에서는 계측 지연현상이 나타나지 않은 것으로 확인되었다.

본 연구는 기초연금 지급 기준이 전체 노인에서 소득 하위 70% 노인에게 선별적으로 설계됨에 따라 필연적으로 발생하는 소득역전 현상에 주목하고, 기초연금제도의 소득역전 현상을 완화하기 위한 방안을 찾고자 시도되었다. 이를 위해 기초연금의 전신인 기초 노령연금의 소득역전 완화 효과를 분석하고, 완화구간 증가에 따른 추가소요예산을 추계 하였으며, 기존 8단계 감액 외에도 4단계, 16단계 감액 방식을 상호 비교하였다. 그 결과 소득역전 완화측면과 예산측면 모두 ‘38%～70% 감액모델’이 유리하다는 것을 확인했다. 본 연구는 소득역전 완화에 관한 몇 안되는 연구인 만큼 후속 연구에서 보다 심도 깊고 다각적인 연구가 필요하고 판단된다.

Based on the system and field of international exchange and cooperation between local governments after the establishment of diplomatic relations between China and South Korea, this paper analyzes the characteristics and future issues of international exchange and cooperation between local governments of China and South Korea. The main achievements of bilateral cooperation are as follows: First, sister cities of friendship between the two sides have developed rapidly. Local government cooperation has both the characteristics of "transborder regional parallel diplomacy" and "trans regional parallel diplomacy". Second, local governments at all levels in South Korea paid relatively low attention to the cities in the central and western regions far away from South Korea in the early stage. In the past 10 years, local governments at all levels in South Korea have gradually started to form sister cities with cities in the central and western regions of China. Third, the bilateral and multilateral cooperation system mechanism of local government cooperation between China and South Korea has gradually became mature. Fourth, various forms of local cooperation at different levels enrich the content of cooperation between China and South Korea and become an important platform for people to people and cultural exchanges between China and South Korea. If it is the geographical and ethnic factors that play an important role in the initial stage of local government exchanges and cooperation between China and South Korea, the policy system will become a new driving force for bilateral cooperation, and the policy promotion at the government level of China and South Korea will become an important consideration for the rational choice of local government transnational cooperation.

이 글은 G2(Group of Two)가 된 중국, 탈유교사회인 현대 중국에서 지식인들은 왜 유학담론을 이야기하며, 유학은 왜 부흥했는가에 대해 살펴보려고 한다. 21세기의 탈유교화된 중국 현대사회에서, 중국지식인들은 왜 100년 전에 그들이 폐기처분했던 공자와 유교문화를 신자본주의시 대인 21세기에 자신들의 새로운 ‘문명가치’로 내세우는가? 현대중국에서 유학은 왜 쇠락했는지, 21세기 오늘날의 중국에서 유학은 왜 다시 부흥하고 있는지, 이러한 ‘유학부흥 현상’을 가능하게 한 중국사회의 매커니즘은 무엇인지를 탐색해보고자 한다. 먼저 중국현대사에서 유학의 쇠락과정에 대해 고찰해보았다. 첫째, 신문화운동 시기에 전통은 무엇 때문에 거부되었는지, 둘째, 문화 대혁명 시기에 공자는 왜 비판을 받았는지를 검토한다. 이 글은 특히 문화연구(Cultural Studies) 의 방법론으로 G2가 된 중국에서의 유학부흥 현상에 대해 살펴보았다. 특히, 국가정책과 지식인의 유학담론, 경제발전과 공자학원의 설립, 대학과 당교(黨校)에서의 전통문화에 대한 교육이 제도권의 커리큘럼에 도입된 것에 대하여 살펴보았다. 이러한 탐색을 통하여 탈유교화된 중국 현 대 사회의 정치문화 상황과 21세기의 중국에서 유교문화의 부흥은 중국이 꿈꾸는 국가의 미래 상과의 관계는 어떠한지를 살펴보았다.

The most important role of air defense system is to attack the air target of enemy to defend the important military unit or facilities. In order to attack the target as soon as it is detected, fast and precise fire signal transfer using the fire control stick is very important. However, it was found that firing is not conducted in the test for fire control stick. In order to find the reason of such problem and improve life cycle of fire control stick, the test was conducted and it was found that chattering occurred and this led to malfunction of signal transfer from control stick to fire control unit of air defense system. In order to draw resolution for this problem, two contact plate made of beryllium copper is suggested to add to the control stick to enhance the contact and reduce chattering effect. The four fire switch prototypes were tested for 100,000 times and it showed its reliability of use.

본 논문에서는 축전식 탈염 공정에서 파울링 현상의 확인과 파울링의 제거공정 조건을 확립하는 연구를 진행하였다. 공급액에 첨가된 파울링 유발 물질인 Humic acid sodium salt (HA)의 농도는 5, 10, 15 mg/L이었다. 주어진 일반의 흡/탈착 조건에서 파울링의 발생은 시간이 지남에 따라 흡착과 탈착 농도의 증가로 확인할 수 있었다. 파울링 현상을 제거하기 위해 흡착 및 탈착에서의 전압과 시간을 변경하였다. 이로부터 흡착 조건 1.2 V/5 min, 탈착 조건 -3 V/2 min에서 파울링 제거를 확인하였다.

The phenomenon of incomplete correspondence between writing and language units is widespread in the Dongba Scripture The White Bat’s Search for Sacred Books. This paper makes a comprehensive analysis and investigation of the incomplete correspondence in the Scripture, and then summarizes several common types and gives examples. This paper hopes to provide a reference for scholars to understand Chinese characters and other mature hieroglyphs in the early stage.

PURPOSES : In this study, a numerical clogging model that can be used to realistically visualize the movement of particles in cylindrical permeability test equipment was proposed based on the system coupling of computational fluid dynamics with the discrete element method and experimental permeability test results. This model can also be used to simulate the interaction of dust particles with bedding particles. METHODS: A 4-way system coupling method with multiphase volumes of the fluid model and porous media model was proposed. The proposed model needs to consider the influence of flow on the dust particles, interaction between the dust particles, and interaction between the dust particles and bedding layer particles. The permeability coefficient of the bedding layer in cylindrical permeability test equipment was not calculated by using the permeability test result, but was estimated by using the particle packing model and Ergun model. RESULTS : The numerical simulation demonstrated a good agreement with the experimental test results in terms of permeability and drain time. Additionally, the initial movement of particles due to the sudden drain hole opening was successfully captured by the numerical model. CONCLUSIONS : A 4-way coupling model was sufficient to simulate the water flow and particle movement in cylindrical permeability test equipment. However, additional tests and simulation are required to utilize the model for more realistic block pavement systems.

PURPOSES : In this study, a series of fundamental falling head permeability tests were conducted on a binary particle mix bedding to determine the minimum water level, bedding layer thickness, and amount of dust that can result in the stable permeability with high repeatability. The determined condition is used to develop a CFD-DEM coupled clogging model that can explain the movement of dust particles in flowing water of a block pavement system. METHODS: A binary particle mixture is utilized to experimentally simulate an ideal bedding layer of a block pavement system. To obtain a bedding layer with maximum packing degree, the well-known particle packing degree model, i.e., the modified Toufar model, was utilized. The permeability of the bedding layer for various water levels, bedding layer thicknesses, and amounts of dust was calculated. The permeability for a small water level drop was also plotted to evaluate the effect of dust on the bedding layer clogging. RESULTS: It was observed that a water level of 100 mm, bedding depth of 70 mm, and dust amount of 0.3 g result in a stable permeability condition with high repeatability. The relationship between the minimum dust amount and surface clogging of the bedding layer was suggested based on the evaluation of the volumetric calculation of the particle and void and the permeability change in the test. CONCLUSIONS: The test procedure to determine the minimum water level, bedding thickness, and dust amount was successfully proposed. The mechanism of clogging on the surface of the bedding layer was examined by relating the volumetric characteristics of dust to the clogging surface.

본 논문은 Shaped charge jet(SCJ)의 관통 과정을 유한요소해석을 통해 모사하여 제트 입사속도, 관통률 그리고 관통량 증분과 같은 물리량들을 획득하였다. 이 물리량들을 hydrodynamic 이론에 적용하여 입사 제트 속도의 효율을 분석한 결과, 입사 속도가 빠른 제트의 관통 효율은 이어지는 느린 제트에 비해 높은 것을 확인하였다. 이 효율은 hydrodynamic limit (HL) 미만인 제트인 경우 큰 폭으로 감소하였다. 한편, 시간에 따른 관통량 증분과 제트 소모량의 비교는 SCJ의 이론적인 관통현상 분석을 위해서는 길이 연장 효과를 고려해야함을 보였다.