• Title/Summary/Keyword: Critical Structure

Search Result 2,377, Processing Time 0.025 seconds

Delamination Prediction of Semiconductor Packages through Finite Element Analysis Reflecting Moisture Absorption and Desorption according to the Temperature and Relative Humidity (유한요소 해석을 통해 온도와 상대습도에 따른 수분 흡습 및 탈습을 반영한 반도체 패키지 구조의 박리 예측)

  • Um, Hui-Jin;Hwang, Yeon-Taek;Kim, Hak-sung
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.29 no.3
    • /
    • pp.37-42
    • /
    • 2022
  • Recently, the semiconductor package structures are becoming thinner and more complex. As the thickness decrease, interfacial delamination due to material mismatch can be further maximized, so the reliability of interface is a critical issue in industry field. Especially, the polymers, which are widely used in semiconductor packaging, are significantly affected by the temperature and moisture. Therefore, in this study, the delamination prediction at the interface of package structure was performed through finite element analysis considering the moisture absorption and desorption under the various temperature conditions. The material properties such as diffusivity and saturated moisture content were obtained from moisture absorption test. The hygro-swelling coefficients of each material were analyzed through TMA and TGA after the moisture absorption. The micro-shear test was conducted to evaluate the adhesion strength of each interface at various temperatures considering the moisture effect. The finite element analysis of interfacial delamination was performed that considers both deformation due to temperature and moisture absorption. Consequently, the interfacial delamination was successfully predicted in consideration of the in-situ moisture desorption and temperature behavior during the reflow process.

Effects of Early- and Late-Feathering Phenotypes on Growth Performance and Mortality in Korean Native Commercial Chickens (토종 실용닭의 깃털 조만성 형태가 산육능력 및 생존율에 미치는 영향)

  • Sohn, Sea Hwan;Choi, Eun Sik;Cho, Eun Jung;Kim, Bo Gyeong
    • Korean Journal of Poultry Science
    • /
    • v.48 no.4
    • /
    • pp.177-184
    • /
    • 2021
  • Sex identification in day-old chicks is essential in the poultry industry. Currently, the feather-sexing using a sex-linked inheritance is a chick sexing method used extensively in the poultry industry. For chicks produced by feather-sexing, all females are early-feathering (EF) chicks and all males are late-feathering (LF) chicks. Therefore, investigating the effects of EF and LF phenotypes on production traits of chickens is critical. The purpose of this study was to analyze and compare the production performance between EF and LF chickens in Korean native commercial chickens. The results showed that the survival rate of the EF chickens was significantly higher than that of the LF chickens, from hatching to 12 weeks of age (P<0.05), with the highest difference observed in females. However, no significant difference was observed in body weight between the EF and LF chickens at almost all ages. In addition, no significant difference was observed between in feed utility, such as average daily feed intake and feed conversion ratio, between the EF and LF groups. In conclusion, although the survival rate of early-feathering chickens was superior to that of late-feathering chickens, no significant difference was observed in growth performance and feed utility among Korean native chickens. The results suggest that production capacity is not influenced by feathering type in the establishment of a breeder structure and production system for feather-sexing Korean native chickens, which is valuable for the practical application of feather-sexing in the poultry industry.

Parametric Study for Seismic Design of Temporary Retaining Structure in a Deep Excavation by Dynamic Numerical Analysis (동적수치해석을 이용한 대심도 흙막이 가시설 내진설계 변수연구)

  • Yang, Eui-Kyu;Yu, Sang-Hwa;Kim, Dongchan;Kim, Jongkwan;Ha, Ik-Soo;Han, Jin-Tae
    • Journal of the Korean Geotechnical Society
    • /
    • v.38 no.12
    • /
    • pp.45-65
    • /
    • 2022
  • In this paper, a diaphragm wall that supports soils and rock was modeled using FLAC, a finite difference analysis program, to evaluate the seismic behavior of temporary retaining structures in a deep excavation. The appropriateness of the numerical model was verified by comparing its results with those of the centrifuge test performed in a similar condition. The bending moment distribution along the diaphragm wall shows a very similar tendency, and the maximum acceleration obtained at the backfill and top of the wall shows a difference within 5%. Based on the developed model, a parametric study was conducted in various input earthquake, ground, and excavation conditions. The maximum structural forces and bending moment under earthquake loading were compared with the maximum values during excavation, from which the critical condition that requires a seismic design was roughly sorted out. The maximum bending moment of a wall that retains soil layers increased 17%. Particularly, the axial force of struts located in loose soils increased 32% under 100 years return period of an earthquake event, which strongly is estimated to require seismic design for structural safety.

A Critical Study of Local Cultural Policy by Village Mural (마을벽화로 본 지역문화정책 비판적 고찰)

  • Jeong, Yoonsoo
    • 지역과문화
    • /
    • v.7 no.3
    • /
    • pp.81-108
    • /
    • 2020
  • This study aims to critically consider the local cultural policies of the government and local governments by village mural. Village murals, which began to be painted in the late 1990s, have been a nationwide cultural phenomenon for decades. In particular, it was consistently used as an important element of various local cultural policies implemented by the government and local governments. The government and local governments have been working on the project for two purposes: 'improving the residential environment' and 'activating tourism' but it has largely focused on 'activating tourism'. This study grasped the concrete status of major village murals across the country through field surveys, one of the case study methods. Also, through the analysis of official documents, the government and local governments operating in the village mural project were analyzed for the policy basis and administrative management plan. As a result of on-site surveys, most of the village murals across the country had problems such as uniform subject matter, low level representation, and poor follow-up management. This is partly based on the experiences and abilities of organizations and artists who participated in the village mural project, but fundamentally, it is due to the projects of the government and local governments that focused on short-term visual tourism rather than long-term improvement of the residential environment. It was confirmed that the projects of the government and local governments were carried out through vertical integration and that there were problems in the actual work, such as requiring specific topics, subject matter, designs and colors. As a result, the village murals 'objectify' the residents and 'romanticized' the place, resulting in a unified visual representation. Therefore, this study suggests that the administration and accounting should be strictly managed, but in actual work, the vertical integration structure should be eased by simplifying various documents and procedures, as well as rich cultural understanding of the target place, selection of various topics, and original subject matter and expressions.

Study of Sound Art Curating (사운드아트 큐레이팅 연구)

  • Lim, Shan
    • The Journal of the Convergence on Culture Technology
    • /
    • v.8 no.5
    • /
    • pp.171-176
    • /
    • 2022
  • This paper examines the historical meaning and value of sound art curating as a key type of interdisciplinary and convergence art practice that has been unfolding since the mid-20th century. Accordingly, this paper summarizes the developmental process from the beginning of 'sound art' to the present, but examines the context of visual art in which the material 'sound' functioned in chronological order, and focuses on curating cases of major sound art exhibitions. The purpose of this study is to analyze the impact and contemporary significance of the provided aesthetic experience. To this end, the text is divided into three sections and developed. The first section recognizes that the late 19th century futurist and Dadaist sound poetry, followed by Marcel Duchamp's 1913 attempt to combine musical score with visual art, had a profound influence on the visual music of avant-garde composer John Cage. This explains why this background caused the emergence of exhibitions dealing with 'sound' as a new medium. The second section explains that in the 1970s, sound as an artistic medium played a role in reflecting the critical relationship with the exhibition space dominated by visuality. In the third section, we analyze the curatorial methodology that allows the audience to experience sound as if it were a visual object within the organization of the exhibition hall from the 1980s to the present. Through this process, this paper critically treats the historical practice of customizing the perceptual structure in the exhibition hall, and considers the meaningful methodology of sound art curating considering the role of sound full of vitality in the contemporary art scene.

A Comparative Study Concerning the Idea of 'Conscience' in Daesoon Thought and Heidegger: Focusing on the Tendency of 'Conscience' to Return to Itself (대순사상과 하이데거의 '양심' 개념에 대한 비교연구 - 근원을 향한 '양심'의 회귀적 특성에 대한 논의를 중심으로 -)

  • Kim, Dae-hyeon
    • Journal of the Daesoon Academy of Sciences
    • /
    • v.28
    • /
    • pp.243-265
    • /
    • 2017
  • In this research, I define 'conscience' in Daesoon thought as the 'Restorative capability of returning to one's roots.' The notion of conscience forms a structure of separation and return, and it is connected to the ascetic aim of realizing human perfection. The conscience opens up potential possibilities and leads realization of potential possibilities by returning to the the point of origin. In the middle of separation and return, the conscience acts as the power of subjectivity possessed by human beings which is known as 'In jon (Human Nobility)' in Daesoon thought. The concept of conscience in Daesoon thought is connected with the subjectivity of In jon and free will as well as the character of subjectivity. This shares commonalities with critical thinking, modern characteristics, and the subjectivity of Heidegger's existentialism. Heidegger describes human fate from an existentialist vantage point using terms such as dasein, Geworfenheit, and Entwurf, and establishes human existence as an act of self-recovery from within in a lonely existential establishment. Daesoon thought implies that humanity is the root of ultimate reality, and this description is in sharp contrast with the thrownness (Geworfenheit) of Heidegger's subjectivity. Therefore, Daesoon thought can be seen as unique in its characterization of humanity as being connected to the root of ultimate reality, autonomy, and independent existence.

A Recommendation of the Technique for Measurement and Analysis of Passive Surface Waves for a Reliable Dispersion Curve (신뢰성 있는 분산곡선의 결정을 위한 수동표면파 측정 및 분석기법의 제안)

  • Yoon, Sung-Soo
    • Journal of the Korean Geotechnical Society
    • /
    • v.23 no.2
    • /
    • pp.47-60
    • /
    • 2007
  • Conventional active surface wave measurements performed using a transient or continuous source are often limited in the maximum depth of penetration due to the difficulty of generating low-frequency energy with reasonably portable sources. This limitation may inhibit accurate seismic site response calculations because of the inability to define deeper subsurface structure. By measuring surface wave generated by passive sources including microtremors and cultural noise, it is possible to overcome this problem and develop soil stiffness profiles to much larger depth. Reliability of dispersion estimates from the passive surface wave measurements is critical to present reliable shear wave velocity profiles and can be improved by the measurements and analyses of passive surface waves based on correct understanding of systematic errors included in passive dispersion data. In this study, the systematic errors caused by poor wavenumber resolution and energy leakage into sidelobes in passive tests are mainly explored. Recommendations for reliable passive surface wave measurements and dispersion estimates are presented and illustrated at a site in San Jose, California, U.S.

Interfacial Properties of Propylene Oxide Adducted Sodium Laureth Sulfate Anionic Surfactant (프로필렌 옥사이드를 부가한 소듐 라우레스 설페이트 음이온 계면활성제의 계면 특성에 관한 연구)

  • Jeong Min Lee;Ki Ho Park;Hee Dong Shin;Woo Jin Jeong;Jong Choo Lim
    • Applied Chemistry for Engineering
    • /
    • v.34 no.3
    • /
    • pp.264-271
    • /
    • 2023
  • In this study, ASCO SLES-430 surfactant was synthesized by adducting 3 moles of ethylene oxide and 1 mole of propylene oxide to lauryl alcohol followed by a sulfation process, and the structure of the synthesized ASCO SLES-430 was elucidated by performing FT-IR, 1H-NMR and 13C-NMR analyses. Interfacial properties such as critical micelle concentration, static surface tension, emulsification index, and contact angle were measured, and environmental compatibility indices such as oral toxicity and skin irritation were also estimated for ASCO SLES-430. Both results were compared with ASCO SLES-226 and ASCO SLES-328 SLES surfactants possessing 2 moles and 3 moles of ethylene oxide, respectively. In particular, both foaming ability and foam stability were evaluated for ASCO SLES-430 and compared with ASCO SLES-226 and ASCO SLES-328, which have been widely used in detergent products, in order to test the potential applicability of ASCO SLES-430 in detergent product formulation for a small capacity built-in washing machine.

On the Evolution of Hong Kong's Nativism and Its Public Law Solutions (论香港本土主义的流变及其公法应对)

  • Man, Lai Pui;Yinhao, Tan
    • Analyses & Alternatives
    • /
    • v.3 no.1
    • /
    • pp.93-133
    • /
    • 2019
  • Throughout history, there are three clues of dualistic structures for the development of Hong Kong's nativism. First, inward attribution and outward lookingare two paths to the formation of Hong Kong's nativism. In the dualistic framework of "self-others", nativism is formed. The formation path of "outward looking"can be seen everywhere in the construction history of Hong Kong's nativism. It is under the reflection of "two mirrors" with Britain and Chinese mainland that Hong Kong people acquire the concept of "Hong Kong's nativism". Second, there are two aspects of Hong Kong's nativism: economic and cultural aspect and political aspect. With the gradual development of Hong Kong's history, these two aspects come into being and are closely bound up, thus constituting Hong Kong's nativism today. The third clue is the most critical one. The subjectivity of colonization and decolonization are two different forms of Hong Kong people's subjectivity. These three clues run through the whole process of the construction of Hong Kong nativism, and are carried out in three stages of development: "Origin (1960s-1970s): Preliminary Construction of Hong Kong's Nativism", "Development of Hong Kong's Nativism (1980s-1997): Awakening of Political Aspect" and "Formation and Alienation of Hong Kong's Nativism (1997-present): Deformed "decolonization". Along the evolution of Hong Kong's nativism, with the disintegration of colonialism, Hong Kong people have gradually transited from the subjectivity of colonization to the subjectivity of decolonization, but the process of "decolonization" has not been completed up to now.When nativism loses its native complex from the perspective of "inherent in China", and further develops into the "separatism" of anti-constitutional system and anti-national continuity and unity, it will challenge the stability of the relationship between the central government and the Special Administrative Region under the "one country, two systems". At the same time, it will have a greater impact on the political structure and the rule of law system of Hong Kong, and trigger a series of public law problems that need to be solved urgently. In this regard, on the one hand, we should re-clarify the relationship between the central government and the region under the "one country, two systems" in light of the new situation of democratic political development in Hong Kong, and improve Hong Kong's governance mechanism on the basis of the constitution and the basic law; on the other hand, we should actively learn from the German defensive democracy system to systematically interpret, integrate and apply Hong Kong's existing legal resources so as to effectively curb the development of local separatist forces.

  • PDF

Receptor binding motif surrounding sites in the Spike 1 protein of infectious bronchitis virus have high susceptibility to mutation related to selective pressure

  • Seung-Min Hong;Seung-Ji Kim;Se-Hee An;Jiye Kim;Eun-Jin Ha;Howon Kim;Hyuk-Joon Kwon;Kang-Seuk Choi
    • Journal of Veterinary Science
    • /
    • v.24 no.4
    • /
    • pp.51.1-51.17
    • /
    • 2023
  • Background: To date, various genotypes of infectious bronchitis virus (IBV) have co-circulated and in Korea, GI-15 and GI-19 lineages were prevailing. The spike protein, particularly S1 subunit, is responsible for receptor binding, contains hypervariable regions and is also responsible for the emerging of novel variants. Objective: This study aims to investigate the putative major amino acid substitutions for the variants in GI-19. Methods: The S1 sequence data of IBV isolated from 1986 to 2021 in Korea (n = 188) were analyzed. Sequence alignments were carried out using Multiple alignment using Fast Fourier Transform of Geneious prime. The phylogenetic tree was generated using MEGA-11 (ver. 11.0.10) and Bayesian analysis was performed by BEAST v1.10.4. Selective pressure was analyzed via online server Datamonkey. Highlights and visualization of putative critical amino acid were conducted by using PyMol software (version 2.3). Results: Most (93.5%) belonged to the GI-19 lineage in Korea, and the GI-19 lineage was further divided into seven subgroups: KM91-like (Clade A and B), K40/09-like, QX-like (I-IV). Positive selection was identified at nine and six residues in S1 for KM91-like and QX-like IBVs, respectively. In addition, several positive selection sites of S1-NTD were indicated to have mutations at common locations even when new clades were generated. They were all located on the lateral surface of the quaternary structure of the S1 subunits in close proximity to the receptor-binding motif (RBM), putative RBM motif and neutralizing antigenic sites in S1. Conclusions: Our results suggest RBM surrounding sites in the S1 subunit of IBV are highly susceptible to mutation by selective pressure during evolution.