• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2007년도 추계 학술대회논문집
• /
• pp.56-59
• /
• 2007

The screech tone of an underexpanded jet is numerically calculated without any specific modeling for the screech tone itself. A fourth-order optimized compact scheme and fourth-order Runge-Kutta method are used to solve the 2D axisymmetric Euler equation. The Fourier transform of pressure signal at upstream shows the directivity pattern of the screech tone very clearly. Pressure signal is shown to observe the generation of the screech tone. Most importantly, we can simulate the axisymmetric mode change of the screech tone very precisely with the proposed method. It can be concluded that the basic phenomenon of the screech tone including its frequency can be calculated and its mode change can be simulated with inviscid Euler equations.

• 패션비즈니스
• /
• 제21권1호
• /
• pp.12-31
• /
• 2017

Korean commercial-organized girl groups were remarkable in the late 1990's. However, by the late 2000's, girl groups had an even more profound effect on Korean popular music compare to past influences. This study aimed to analyze the social-cultural meaning of the changing appearance of girl group between the first and second-generations. For this purpose, this study analyzed media image and text, based on a social-cultural context, about 13 girl groups. The results are as follows. First, while the first -generation girl group tended to maintain girlish/sexy images trying to the male desire, the second -generation girl group strategically showed various sexual identities such as femininity, masculinity, masculinity and androgyny along with contextual sexual images. The reason why girl groups increased the number of strategic images featuring various sexual identities was in order to appeal to a wide, diverse audience. Second, the second generation girl groups had - slim bodies with great athleticism, basically due to trainee system. Because of this, their semiotic body images have been commercially used to promote the consumption. Third, the second generation girl groups - were the bigger stars than first generation girl groups - because the members worked in many different fields. Therefore, the group members' images were successful consumed directly and then reproduced symbolically. Fourth, each member of the second -generation girl groups characterized by appearing in diverse, yet familiar images, through various media sources. Although the intention of this was to have recognition and popularity, it became difficult for them to change their image once one particular image was deemed popular.

• 기록학연구
• /
• 제54호
• /
• pp.151-178
• /
• 2017

본 연구는 기록관리 현장의 전자기록관리영역의 문제를 확인하고 IT신기술의 도입으로 인해 급변하고 있는 기록 생산 및 관리 환경의 변화에 조응할 수 있는 새로운 전자기록관리체계의 설계를 위해 과제를 도출하는 것을 목적으로 한다. 새로운 정부의 기록관리 혁신에 맞추어 프로세스, 시스템, 인프라 모든 영역에서 이전과는 다른 차세대 기록관리 개념 설계가 이루어져야 하는 시기이다. 이러한 관점에서 차세대 기록관리의 가치와 지향이 어떠해야 하는지 방향성을 도출하고 이에 따라 프로세스, 시스템, 인프라 영역의 문제를 확인하고 과제화하였다.

• Nuclear Engineering and Technology
• /
• 제51권2호
• /
• pp.546-555
• /
• 2019

Since the first nuclear reactor first critical, nuclear systems has gone through four generations of history, and the fourth generation nuclear system will be truly realized in the near future. The notions of SVBR and lead-bismuth eutectic alloy coolant put forward by Russia were well received by the international nuclear science community. Lead-bismuth eutectic alloy with the ability of the better neutron economy, the low melting point, the high boiling point, the chemical inertness to water and air and other features, which was considered the most promising coolant for the 4th generation nuclear reactors. This study mainly focuses on the structural design optimization of the 4th-generation reactor coolant pump, including analysis of external characteristics, inner flow, and transient characteristic. It was found that: the reactor coolant pump with a central symmetrical dual-outlet volute structure has better radial-direction balance, the pump without guide vane has better hydraulic performance, and the pump with guide vanes has worse torsional vibration and pressure pulsation. This study serves as experience accumulation and technical support for the development of the 4th generation nuclear energy system.

• 복식문화연구
• /
• 제28권6호
• /
• pp.830-844
• /
• 2020

The fourth Industrial Revolution, known as digital transformation, has made MZ generation to be the focus of the new consumer market, brought about the use of technological platforms a new consumption method. Currently, as various types of content collaboration are emerging that specifically targeting at the MZ generation. Content collaboration are considered an integration of content to create new values through co-existence and co-prosperity. This study identified the characteristics of collaboration of fashion brands from 2018 using literature and online news articles, and identified and classified through case studies of it determined movie content, game and virtual characters. By this research, it shown that collaboration with movie contents have increased the collaborative synergy by using the story in global media content. Collaboration with mobile games was generally used by young casual and sportswear brands. These brands which utilized characters from mobile games popular with to attract more teen consumers and strengthen brand awareness by adding values of high-technology and scarcity to the familiar images. In addition, collaboration with virtual characters has expanded value of the collaborative approach on expanding the range of advanced digital technology, from a promotional strategy during the distribution process through to the use of virtual models. As such, collaboration using the various types of content has developed beyond simple integration of identities among various areas, integrated products or brands that as a new value.

• 디지털산업정보학회논문지
• /
• 제19권3호
• /
• pp.89-103
• /
• 2023

The purpose of this study is to investigate the mediating effect of news literacy in the relationship between sense of community and political efficacy. This study conducted a survey targeting the MZ generation. The survey was conducted online, and data from 309 cases were used for analysis. The research results are as follows. As a result of correlation analysis between sense of community, political efficacy, and news literacy, it was found that there was a statistically significant correlation between sense of community and news literacy sub factors. Second, the relationship between sense of community and political efficacy was found to have a significant positive effect on political efficacy as sense of community increased. Third, the relationship between sense of community and news literacy was confirmed to have a significant positive effect on news literacy as sense of community increased. Fourth, regarding the relationship between news literacy and political efficacy, it was confirmed that news literacy has a significant effect on political efficacy. Fifth, in the relationship between sense of community and political efficacy, news literacy was found to mediate the relationship between sense of community and political efficacy of the MZ generation. Based on the research results, news literacy education is required from the perspective of civic education, and differentiated educational contents by age are proposed.

• Journal of Veterinary Science
• /
• 제25권3호
• /
• pp.47.1-47.12
• /
• 2024

Importance: Staphylococcus aureus and Escherichia coli contribute to global health challenges by forming biofilms, a key virulence element implicated in the pathogenesis of several infections. Objective: The study examined the efficacy of various generations of cephalosporins against biofilms developed by pathogenic S. aureus and E. coli. Methods: The development of biofilms by both bacteria was assessed using petri-plate and microplate methods. Biofilm hydrolysis and inhibition were tested using first to fourth generations of cephalosporins, and the effects were analyzed by crystal violet staining and phase contrast microscopy. Results: Both bacterial strains exhibited well-developed biofilms in petri-plate and microplate assays. Cefradine (first generation) showed 76.78% hydrolysis of S. aureus biofilm, while significant hydrolysis (59.86%) of E. coli biofilm was observed by cefipime (fourth generation). Similarly, cefuroxime, cefadroxil, cefepime, and cefradine caused 78.8%, 71.63%, 70.63%, and 70.51% inhibition of the S. aureus biofilms, respectively. In the case of E. coli, maximum biofilm inhibition (66.47%) was again shown by cefepime. All generations of cephalosporins were more effective against S. aureus than E. coli, which was confirmed by phase contrast microscopy. Conclusions and Relevance: Cephalosporins exhibit dual capabilities of hydrolyzing and inhibiting S. aureus and E. coli biofilms. First-generation cephalosporins exhibited the highest inhibitory activity against S. aureus, while the third and fourth generations significantly inhibited E. coli biofilms. This study highlights the importance of tailored antibiotic strategies based on the biofilm characteristics of specific bacterial strains.

• 한국수소및신에너지학회논문집
• /
• 제34권2호
• /
• pp.149-154
• /
• 2023

In the Fourth Industrial Revolution, hydrogen energy is in the spotlight. There is a difficulty in commercialization due to the lack of hydrogen infrastructure. Therefore, a lot of hydrogen should be imported and a method using ammonia is the most useful. In this study, using the mixed gas of hydrogen and nitrogen generated when ammonia is decomposed, the hydrogen separation performance is to be tested. Hydrogen was separated using an electrochemical hydrogen compressor based on a fuel cell and the experiment was conducted by changing the ratio of hydrogen and nitrogen. In addition, the performance was also compared by the difference both the pressure and the membrane.

• 한국과 국제사회
• /
• 제1권2호
• /
• pp.129-148
• /
• 2017

2013년에 시진핑 체제가 본격적으로 출범하였지만 대내외적으로 많은 난관에 직면하였다. 시진핑은 지속적인 경제성장과 부정부패 척결 등의 정치개혁으로 사회를 통합하여 안정시켜야 하며, 미국과의 새로운 관계정립과 한반도의 비핵화 등 난제들은 해결해야 한다. 이에 본 연구는 정치지도자들의 정치리더십이 국가발전의 중요한 변수가 된다고 보아 막스 베버(Max Weber)의 정치지배유형을 활용하여 시진핑을 비롯한 중국의 정치지도자를 분석하였다. 시진핑 이전 제1세대 정치지도자부터 제4세대 정치지도자까지를 검토해 보면, 제1세대와 제2세대 정치지도자의 정치지배유형은 합법적 지배성향보다는 카리스마적 지배성향을 보인다. 하지만 제3세대 정치지도자는 합법적 지배성향보다는 전통적 지배성향을, 제4세대 정치지도자는 전통적 지배성향보다 합법적 지배성향을 보여주고 있다. 한편 시진핑의 정치지배유형은 정치적 성장에서는 전통적 지배성향을, 정치권력의 구축과정에서는 합법적 지배성향을 보이지만 집권이후에는 카리스마적 지배성향을 보이고 있다. 시진핑은 중국의 독특한 권력교체방식과 권위주의적 후계체제로 전통적인 지배성향을 보이지만 당대회나 전국인민대표대회 등 적법한 절차에 통해 최고지도자로 선출되었기 때문에 합법적 지배성향도 있으며, 정책추진과정에서는 마오쩌둥과 덩샤오핑과 같은 카리스마적 지배성향도 보이고 있다.

• 대한심미치과학회지
• /
• 제3권1호
• /
• pp.23-31
• /
• 1995

The All-Bond system is a unique development in the field of adhesive dentistry. It is a universal bonding system that will bond composite to all dental-related surfaces: dentin, enamel, metal alloy (precious and nonprecious), amalgam, porcelain, and composite. It is also the only system that allows use of both the conservative and all-etch techniques. The main purpose of this paper is to explain the features of the All-Bond system. Its chemistry and a working hypothesis are shown as well.