• Journal of the Earthquake Engineering Society of Korea
• /
• v.23 no.3
• /
• pp.159-167
• /
• 2019

2016 Gyeongju and 2017 Pohang earthquakes led Koreans to acknowledge that the Korean peninsula is not an earthquake-free zone anymore. Among various buildings crucial to after-shock recovery, general hospital buildings, especially existing old ones, are very significant so seismic retrofitting of those must be an important issue. Self-centering energy dissipative(SCED) brace is one of retrofitting methods, which consists of tendon with restoring force and friction device capable of dissipating seismic energy. The strength of the SCED brace is that the tendon forces a structure to go back to the original position, which means residual drift can be negligible. The residual drift is a very important parameter to determine usableness of general hospitals after shock. To the contrary, buckling-restrained braces(BRB) are also a very effective way to retrofit because they can resist both compressive and tensile, but residual drift may exist when the steel core yields. On this background, the seismic retrofitting effect of general hospitals reinforced with SCED braces was investigated and compared to that of the BRD in this study. As a result, although the floor acceleration cannot be reduced, the story drift and residual drift, and the shear demand of walls significantly decreased. Consequently, seismic retrofitting by SCED braces are very effective for domestic low-rise general hospitals.

• Smart Structures and Systems
• /
• v.23 no.4
• /
• pp.329-335
• /
• 2019

Structural fuses are made up from oriented steel plates to be used to resist seismic force with shear loading resistance capabilities. The damage and excessive inelastic deformations are concentrated in structural fuses to avoid any issues for the rest of the surrounding elements. Recently developed fuse plates are designed with engineered cutouts leaving flexural or shear links with controlled yielding features. A promising type of link is proposed to align better bending strength along the length of the link with the demand moment diagram is a butterfly-shaped link. Previously, the design methodologies are purely based on the flexural stresses, or shear stresses only, which overestimate the dampers capability for resisting against the applied loadings. This study is specifically focused on the optimized design methodologies for commonly used butterfly-shaped dampers. Numerous studies have shown that the stresses are not uniformly distributed along the length of the dampers; hence, the design methodology and the effective implementation of the steel need revisions and improvements. In this study, the effect of shear and flexural stresses on the behavior of butterfly-shaped links are computationally investigated. The mathematical models based on von-Mises yielding criteria are initially developed and the optimized design methodology is proposed based on the yielding criterion. The optimized design is refined and investigated with the aid of computational investigations in the next step. The proposed design methodology meets the needs of optimized design concepts for butterfly-shaped dampers considering the uniform stress distribution and efficient use of steel.

• Journal of the Korean institute of surface engineering
• /
• v.55 no.2
• /
• pp.102-119
• /
• 2022

Gold plating is used as a coating of connecter in printed circuit boards, ceramic integrated circuit packages, semiconductor devices and so on, because the film has excellent electric conductivity, solderability and chemical properties such as durability to acid and other chemicals. As increasing the demand for miniaturization of printed circuit boards and downsizing of electronic devices, several types of electroless gold plating solutions have been developed. Most of these conventional gold plating solutions contain cyanide compounds as a complexing agent. The gold film obtained from such baths usually satisfies the requirements for electronic parts mentioned above. However, cyanide bath is highly toxic and it always has some possibility to cause serious problems in working environment or other administrative aspects. The object of this investigation was to develop a cyanide-free electroless gold plating process that assures the high stability of the solution and gives the excellent solderability of the deposited film. The investigation reported herein is intended to establish plating bath composition and plating conditions for electroless gold plating, with thiomalic acid as a complexing agent. At the same time, we have investigated the solution stability against nickel ion and pull strength of solder ball. Furthermore, by examining the characteristics of the plated Au plating film, the problems of the newly developed electroless Au plating solution were improved and the applicability to various industrial fields was examined. New type electroless gold-plating bath which containing thiomalic acid as a complexing agent showing so good solution stability and film properties as cyanide bath. And this bath shows the excellent stability even if the dissolved nickel ion was added from under coated nickel film, which can be used at the neutral pH range.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.4
• /
• pp.153-160
• /
• 2022

In this paper, we propose the relationship between self-determination, home training satisfaction, and reuse of police-related students who participate in home training and train their physical strength. The subjects of this study were students enrolled in the Department of Police Administration and Police Martial Arts at D, S, and K universities in Busan and Gyeongnam area. Among them, 349 students who had participated in home training were surveyed. As a result of verifying the relationship between self-determination, exercise satisfaction, and reuse factors using the collected data, SPSSWIN VER 25+, AMOS 20.0 program, First, autonomy, competence, and relationship, which are sub-factors of self-determination of home training participants, had a positive effect on home training satisfaction. Second, exercise satisfaction of home training participants had a positive effect on home training reuse. Based on the research results,It is essential to identify and manage what home training participants demand. It is believed that this can be a positive process for the development of home training.

• International Journal of Advanced Culture Technology
• /
• v.10 no.3
• /
• pp.146-155
• /
• 2022

The purpose of this study is to investigate the recyclability of Shenlong in China using SWOT. The main analysis results are as follows. First, provided that the company's current capacity utilization rate is seriously insufficient, reducing staff is one among the effective ways. Second, Shenlong should open a web store to cater to young people's online shopping behavior, and further expand the brand visibility using national mainstream media and online shopping platforms like Taobao and JingDong to market Dongfeng Peugeot and Dongfeng Citroen on the whole network. Third, under the premise of maintaining the present best-selling models, Shenlong should appropriately reduce the amount of models, adjust the assembly capacity ratio of every model and every displacement in real time per the newest market trends, increase the agility of auto companies' production, and timely meet the wants of domestic consumers. Fourth, dual-brand coordination and channel integration are very necessary, and also the profitability and profitability of dealers are going to be further improved, thereby increasing sales. Fifth, target building new energy leading products of Shenlong, strive to attain the forefront of the industry within the sales of recent energy vehicles within 5 years, and gradually expand new energy vehicle products from passenger vehicles to passenger vehicles and commercial vehicles. Finally, the marketing field of Shenlong Automobile should achieve "three major changes", that is, change from a goal-driven type to a demand-driven type, cancel the bundling of outlet invoicing goals and delivery incentive tiers; start from basic capabilities, and set pragmatic and challenging goals; focus Channels, to realize following the activation of outlets, and single store sales increase.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.2
• /
• pp.618-627
• /
• 2021

Functional cosmetics are products that help emphasize certain functions such as skin whitening, wrinkle reduction and UV protection. Functional cosmetic items have expanded since 2017. Korea's functional cosmetics industry has focused on skin whitening, wrinkle reduction, UV protection, and high-performance items including medical cosmetics that are in the research and development stage. France leads the international export performance rankings followed by the United states and Germany. France's cosmetic industry is renowned for emphasizing mechanism driven functional cosmetics in bio-industrial and functional materials, while the United states cosmetic industry is in high demand for luxury premium products. The German cosmetic industry is showing growing strength in bio high tech functional cosmetics. For the Korean cosmetic industry to challenge the top 3, it will also have to develop new material of various functional cosmetics that can be applied to emerging industries, and develop a variety of industry equipment in an environment where politics and economy are backed by more focus on research.

• Korean Association of Arts Management
• /
• no.60
• /
• pp.37-68
• /
• 2021

The purpose of this study is to understand the attractiveness of the vinyl record industry and derive implications by analyzing the structure of the industry. A few previous studies pay attention to the rapidly increasing demand for vinyl records, especially from a consumer point of view, and unlike the analysis of the consumption and vinyl record industry, this study focuses on the subjects of production and distribution of vinyl records. This paper collects data through in-depth interviews with experts in the vinyl record industry and various secondary data, which is analyzed by Porter(1980/2008)'s Five Forces Model. According to the analysis, the attractiveness of the vinyl record industry is positive in terms of the appropriate competitive strength in the industry and weak bargaining power of buyers, but negative in terms of the strong bargaining power of new entrants and substitutes. The outcome of this research has significance as basic data implying that companies that are trying to enter the vinyl record industry need to make strategic decisions.

• Membrane Journal
• /
• v.32 no.2
• /
• pp.91-99
• /
• 2022

It is a global challenge to fulfill the demand for clean water at an affordable cost to all the strata of the population. Desalination of seawater as well as brackish water by the membrane separation process is a well-established and cost-efficient method. However, there is still inherent problem of membrane fouling, disposal of the reject as well as a capital-intensive process. While electrodialysis (ED) is a membrane-based separation process in which a driving force is the potential difference. The advantages of ED process are excellent efficiency and low operation cost. Ion exchange membrane (IEM) used in the ED process needs to have higher chemical and thermal stability along with excellent mechanical strength for long-term use without losing its efficiency. The ion exchange capacity of the ED membrane is largely dependent on the conductivity of IEMs. In this review, the modification strategy of the pristine membrane to enhance the stability and ion conductivity of cation exchange membrane (CEM) and anion exchange membrane (AEM) is discussed.

• Journal of the Korean Wood Science and Technology
• /
• v.51 no.3
• /
• pp.207-221
• /
• 2023

The increasing demand for clean energy requires considerable effort to find alternative energy sources, such as briquettes. This research aims to develop a charcoal briquette with added pine resin (API) that has excellent combustion speed and distinctive aroma. Briquettes are composed of charcoal, pine resin (concentration: 0%-30%), and starch (up to 7%). They are produced in several stages, including coconut shell pyrolysis in conventional combustion, to obtain charcoal for the briquette precursor. Briquette compaction is conducted by mixing and densifying the charcoal, pine resin, and starch using a hydraulic press for 3 min. The hydraulic press has a total surface area and diameter of 57.7 cm² and 3.5 cm, respectively. The briquettes are dried at different temperatures, reaching 70℃ for 24 h. The study results show that the briquettes have a thickness and diameter of up to 2 and 3.5 cm, respectively; moisture of 2.18%-2.62%; ash of 11.61%-13.98%; volatile matter of 27.15%-51.74%; and fixed carbon content of 40.24%-59.46%. The compressive strength of the briquettes is 186-540 kg/cm². Their calorific value is 5,338-6,120 kcal/kg, combusting at a high speed of 0.15-0.40 s. The methoxy naphthalene, phenol, benzopyrrole, and lauryl alcohol; ocimene, valencene, and cembrene are found in the API. The API briquette has several chemical compounds, such as musk ambrette, ocimene, sabinene, limonene, 1-(p-cumenyl) adamantane, butane, and propanal, which improve aroma, drug application, and fuel production. Accordingly, API briquettes have considerable potential as an alternative energy source and a health improvement product.

• Transactions of the Korean hydrogen and new energy society
• /
• v.35 no.2
• /
• pp.146-151
• /
• 2024

The demand for research on materials with excellent cryogenic strength and ductility has been increasing, particularly for applications such as liquid hydrogen (20 K) storage tanks. To effectively utilize liquid hydrogen, a system capable of maintaining and operating at 20 K is essential. Therefore, preliminary research and verification of the cooling system are crucial. In this study, a heat transfer analysis was conducted on a cooling system to meet the cryogenic environment requirements for cryogenic hydrogen chamber, which are conducted at liquid helium temperatures (4 K). The cooling mechanism in a helium cooling system was examined using numerical analysis. The numerical cooling trends were compared with experimentally obtained cooling results. The good agreement between numerical and experimental results suggests that the numerical approach developed in this study is applicable over a wide range of cryogenic systems.