• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.4
• /
• pp.98-104
• /
• 2006

In this paper, for the purpose of investigation the acoustic emission(AE) behaviors during resistance spot welding process and tension test of spec steels. As the results present the resistance spot welding method that can get suitable welding qualities or structural integrity estimating method. The resistance spot welding process consists of several stages: set-down of the electrodes; squeeze; current flow; forging; hold time; and lift-off. Various types of AE signals are produced during each of these stages. For tensile-shear test and cross tensile test in resistance spot welded specimens, fracture pa 야 ems are produced: tear fracture; shear fracture; and plug fracture. Tensile-shear specimens strength appeared higher than cross tensile specimens one. In case of tensile-shear specimen happened tear fracture that crack happens in most lower plate. Also, in case of cross tensile specimens, upper plate and lower plate are detached perfect fracture was exposed increases a little as acting force is lower than ordinary welding condition. Therefore, the structure which is combined by resistance spot welding confirmed that welding design must attain so that shear stress may can interact mainly.

• Journal of the Korean Magnetics Society
• /
• v.16 no.4
• /
• pp.211-215
• /
• 2006

Measurement methods in order to measure the mechanical properties nondestructively have been studied. The mechanical properties of the structural and turbine rotor steels are related with their magnetic properties. If the magnetic properties of the cold rolled carbon steel sheet (CR) for a car are measured nondestructively, its mechanical properties are analogized by their magnetic properties. And then the mechanical properties are monitored on-line by measuring the magnetic properties. We prepared three CR materials, CBQ 3060, CBQ 3041, and CBQ 3036, were prepared in order to measure their mechanical and magnetic properties. The Vickers hardness,yield strength, and tensile strength were measured by ASTM E 8M, and the reversible magnetic permeability was measured by the surface type probe. The coercivity calculated by the peak interval of reversible magnetic permeability increased linearly with the increase of Vickers hardness, yield strength, and tensile strength. The amplitude of the peak interval of reversible magnetic permeability drastically decreased when the lift-off was increased.

• Journal of the Korean housing association
• /
• v.15 no.2
• /
• pp.97-105
• /
• 2004

This research is about Apartment Remodeling Upgrading Programme by Singapore Housing Development Board(HDB). For this study, we visited HDB and made field survey of the projects. There are basically three types of upgrading, namely, Precinct Upgrading, Apartment Block Upgrading and Flat Upgrading. Precint Upgrading refers the upgrading of services and facilities of the precinct. It involves the extention of open space, car-park, commercial space and additional covered linkways. These afford the residents greater convenience and comfort and generally enhance the environment of the community. Apartment Upgrading refers the upgrading of the block facade, improvements to the elevator, lift lobbies, letter boxes, trash chute and rain chute. The upgrading improves the quality of life of the residents. Flat Upgrading Involves the addition of space which may be in the form of a new Utility-room, replacement of old services, piping and equipment within an apartment unit. These provide the residents with a bigger and more comfortable living space.

• Journal of the Korea Furniture Society
• /
• v.12 no.1
• /
• pp.131-142
• /
• 2001

Cultural needs of human have grown enormously. Consumer trend and individual taste have become more individualistic and diversified. Efforts to improve the quality of life have changed the concept of lift space as well as the concept of interior life supplies. Products are no longer standardized and produced in massive scale, thus a shift of value has risen. Damages done by the economical development have made consumers take interests in products that are more natural and in harmony with human beings. It is a tendency that wooden materials are becoming a preference as a specific alternative. There is a great social change with a new paradigm like this. Considering the change, we propose a new vision and activation plan on design development of wooden products through specific and practical studies by the system of educational and industrial cooperation which is an organic association system for developing human resources of educational system and producing profits of industry. From it, we can expect great effects as a competitive design of coming future.

• Journal of Dairy Science and Biotechnology
• /
• v.19 no.1
• /
• pp.39-48
• /
• 2001

As the development of medical technology and the elevation of the standard of living, the population rate of elderly people in Korea is increasing gradually. To keep a good lift quality of the elderly, both appropriate exercise and nutrients intake are necessary for them. Dairy products are known for the good source of variable nutrients including functional components and bioactive peptides such as Ig, lactoferrin, MFGM, OPP, CPP, GMP, sialic acid etc that are required especially for elderly people. However, they are classified as the low dairy products consumption group recently. For the promotion of dairy product consumption of elderly people, variable and specialized dairy products for the elderly should be researched and developed with the strengthened publicity activities.

• Journal of Dairy Science and Biotechnology
• /
• v.23 no.2
• /
• pp.143-148
• /
• 2005

Korea dairy market has greatly expanded recently by growing up the consumer's demands of high quality of milk products and their functionality due to expanding of well being lift trends. However, life cycle of dairy products is shorter than ever before and low birth rate is a common trend of Korean people. Moreover due to the national economy crisis, most of dairy companies are faced with the pressure of new milk products development and their sales. This paper deals with the development of Korea dairy industry by chronological order and deals with the future applicable new dairy foods and advanced dairy technology.

• International Journal of Korean Welding Society
• /
• v.3 no.2
• /
• pp.29-39
• /
• 2003

The durability and reliability of thermal barrier coatings (TBCs) play an important role in the service reliability, availability and maintainability (RAM) of hot­section components in advanced turbine engines for aero and utility applications. Photostimulated luminescence spectroscopy (PSLS) and electrochemical impedance spectroscopy (EIS) are being concurrently developed as complimentary non­destructive evaluation (NDE) techniques for quality control and life­remain assessment of TBCs. This paper overviews the governing principles and applications of the luminescence and the impedance examined in the light of residual stress, phase constituents and resistance (or capacitance) in TBC constituents including the thermally grown oxide (TGO) scale. Results from NDE by PSLS and EIS are discussed and related to the microstructural development during high temperature thermal cycling, examined by using a variety of microscopic techniques including focused ion beam (FIB) in­situ lift­out (INLO), transmission and scanning transmission electron microscopy (TEM and STEM).

• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.1
• /
• pp.147-152
• /
• 2005

The exhaust system of automobile is faced with random or spectrum types of fatigue loads during usage life and so needs to be closely estimated for quality and performance to have enough certainty on design endurance lift during preliminary design process. Structural operation conditions, operation load history, property of material and manufacturing process etc. should be considered by performing experiment approach. Using the software program for predicting fatigue life quickly and exactly in preliminary design stage saves plenty of time and cost generated by fatigue tests. In this paper, fatigue life prediction was performed on the basis of fatigue analysis using MSC/FATIGUE and load data from field test and the life of development items was estimated and compared through the results.

• Journal of Information Technology Applications and Management
• /
• v.30 no.1
• /
• pp.11-19
• /
• 2023

To remove unnecessary background from tooth X-ray images and enhance the sharpness of tooth and gum images, image processing techniques including contrast adjustment and histogram equalization are used. The introduction of two methods for detecting the boundary of the tooth and gum region and separating the tooth and gum from the background. In both cases, the background of the tooth X-ray images could be removed as a result, improving the quality of the images. The proposed method improves MTF (Modulation Transfer Function), an image performance indicator, as a result of measuring MTF. The original image's spatial frequency ranged from 4.73 to 11.40 lp/mm at the 10% response, whereas the proposed image's spatial frequency ranged from 10.90 to 11.85 lp/mm, giving uniformly enhanced results. In contrast, tooth and gums could not be completely separated from the background using Apple's Lift subject from background function.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.05a
• /
• pp.215-218
• /
• 2005

For the production of cold forged parts with near-net-shape attributes, the quality of the tool system is responsible for an essential portion of costs fer the finished components. Therefore, a tool lift is one of the important issues on cold forging industry. There are many complicated variables related with tool life, such as material, heat-treatment, coating, lubricant, process design. In this study, heat-treatment of tool material and lubricant are investigated to improve the tool life. Deep cryogenic treatment of tool steel is very efficient to improve the wear resistance due to the fine carbide. And, friction factor of lubricants for cold forging are measured by the ring compression test. Zinc-Phosphate and $MoS_2$ lubricant is effective to sustain the friction factor under 0.1.