• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.7
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• pp.553-559
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• 2012

A plate-fin heat exchanger is a type of heat exchanger widely used in air conditioners, and tubes and fins are tightly assembled by the mechanical expansion process of tubes. The tube expansion process deforms the grooves inside the tube, and the groove shapes also affect the adhesion between tubes and fins. In this study, the adhesion and heat transfer performance affected by the tube expansion of the non-uniform groove shape tube with different heights are investigated by both analysis and experiments. From the analysis method, it was shown that the contact pressure of non-uniform groove tube is higher than that of the uniform groove tube, and the most appropriate high groove number of the non-uniform groove tube is designed for the maximum contact pressure. From the experimental results, the decreasing rate of the condensation heat transfer coefficient is smaller in the non-uniform groove tube with different heights, compared to the conventional uniform groove tube. Also, the air-side heat transfer coefficient of the non-uniform groove tube with different heights is higher than that of the uniform groove tubes.

• The Transactions of the Korea Information Processing Society
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• v.7 no.3
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• pp.943-952
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• 2000

The surface reconstruction problem from a set of wire-frame contours is very important in diverse fields such as medical imaging or computer animation. In this paper, surface triangulation method is proposed for solving the problem. Generally, many optimal triangulation techniques suffer from the large computation time but heuristic approaches may produce very unnatural surface when contours are widely different in shape. To compensate the disadvantages of these approaches, we propose a new heuristic triangulation method which iteratively decomposes the surface generation problem from a band (a pair of vertices chain) into tow subproblems from two sub-bands. Generally, conventional greedy heuristic contour triangulation algorithm, suffer from the drastic error propagation during surface modeling when the adjacent contours are different in shape. Our divide-and-conquer algorithm, called band partitioning algorithm, processes eccentric parts of the contours first with more global information. Consequently, the resulting facet model becomes more stable and natural even though the shapes are widely different. An interesting property of our method is hat it supports multi-resolution capability in surface modeling time. According to experiments, it is proved to be very robust and efficient in many applications.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.5
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• pp.691-702
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• 2002

The purpose of this study was to provide basic information on the propriety of the ready to wear garment sizes of Tween Generation(ages from 5th grade to 8th grade) who has different clothing preferences in color, styles, and design and also different body sizes and shapes from younger and older students. The objectives of the study were to ascertain (a) the body figure changes occurring during Tween Generation; (b) the coverage of manufactures'garment sizes. The body measurements of elementary school students(5th & 6th grades) and junior high school students(7th & 8th grades) provide the basic statistics for this study. The mean differences of each size within each figure type are compared by using t-teats. The differences in various manufacturers'apparel sizing and figure size are investigated. Also the body measurements and the apparel sizes of the manufacturers are compared in order to evaluate the suitability of the garment size. Results indicate that the body type factors are different in each age group. And manufactures'sizes come out to be much smaller than the actual body measurements. Young casual wear can cover junior high school students satisfactorily but for elementary school students, because of low drop-value, the overall satisfaction with filling is low.

• Journal of Mechanical Science and Technology
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• v.19 no.7
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• pp.1478-1487
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• 2005

A small mixed-type turbine with a diameter of 19.9 mm has been substituted for a rotational part of pencil-type air tool. Usually, a vane-type rotor is applied to the rotational part of the air tool. However, the vane-type rotor has some problems, such as friction, abrasion, and necessity of accurate assembly etc.,. These problems make the life time of the vane-type air tool short, but air tools operated by mixed-type turbines are free of friction and abrasion because the turbine rotor dose not contact with the casing. Moreover, it is assembled easily because of no axis offset. These characteristics are merits for using air tools, but loss of power is inevitable on a non-contacting type rotor due to flow loss, tip clearance loss, and profile loss etc.,. In this study, four different rotors are tested, and their characteristics are investigated by measuring the specific output power. Additionally, optimum nozzle location against the rotor is studied. Output powers are obtained through measured pressure, temperature, torque, rotational speed, and flow rate. The experimental results obtained with four different rotors show that the rotor blade shape greatly influences to the performance, and the optimum nozzle location exists near the mid span of the rotor.

• Structural Engineering and Mechanics
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• v.11 no.1
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• pp.71-87
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• 2001

A frequency domain response analysis is presented for building frames passively controlled by viscoelastic dampers, under harmonic ground excitation. Three different models are used to represent the linear dynamic force-deformation characteristics of viscoelastic dampers namely, Kelvin model, Linear hysteretic model and Maxwell model. The frequency domain solution is obtained by (i) an iterative pseudo-force method, which uses undamped mode shapes and frequencies of the system, (ii) an approximate modal strain energy method, which uses an equivalent modal damping of the system in each mode of vibration, and (iii) an exact method which uses complex frequency response function of the system. The responses obtained by three different methods are compared for different combinations of viscoelastic dampers giving rise to both classically and non-classically damped cases. In addition, the effect of the modelling of viscoelastic dampers on the response is investigated for a certain frequency range of interest. The results of the study are useful in appropriate modelling of viscoelastic dampers and in understanding the implication of using modal analysis procedure for building frames which are passively controlled by viscoelastic dampers against base excitation.

• Fashion & Textile Research Journal
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• v.21 no.2
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• pp.209-219
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• 2019

This study analyzed and compared wearer mobility for different types of clothing that also included the potential to develop firefighter station uniforms using range of motion (ROM) and electromyography (EMG). This study focused on a comparison of wearer mobility affected by different materials and shapes of the station uniforms worn under firefighter turnout gear. Japanese standard uniform (UNI), stretch-wear (ST), and compression-wear (CP) were used as station uniforms for the experiment. This study analyzed wearer movements and quantified ROM and EMG. In addition, the subjective evaluation of wearer mobility and comfort were assessed for comparisons. Nine healthy male students participated in the experiment. Wearer mobility was analyzed using ROM and EMG data obtained by measuring five motions; in addition, subjective evaluations were also obtained. As compared with the standard station uniform, ROM increased 6.8 % and 7.2 % due to stretch-wear and compression-wear. The benefits of wearing stretch material or compression material to improve muscle performance (such as reduced percent of maximum voluntary contraction) were not proven. Differences between materials and designs influenced subjective wearer comfort. In particular, the wearing of compression materials was shown best in terms of wearer comfort that may also allow greater wearer mobility.

• Cross-Cultural Studies
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• v.21
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• pp.271-288
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• 2010

In their everyday life, people form social phenomena and relations through the shapes and habits of animals. Therefore, animals contain the idea of the way of life of certain nations, spiritual and cultural feelings, and the symbolic meaning which can be recognized between the members of the unique nation. The symbolism of animals varies depending on different nations, because the adages are the essence of the language including their culture, thought, custom, and life. Examining their own adages can be one of the ways to find out what the animals symbolize in different nations. Another reason is that they are the dictionaries, reflecting their own way of thinking and traditional values, so to speak. The research shows that, between Korean and Chinese adages, it is in a similar frequency, using materials such as mammals, birds, fishes, reptiles, and insects. The adages are focused on the 12 animals which is familiar to both nations, a rat, an ox, a tiger, a rabbit, a dragon, a snake, a horse, a lamb, a monkey, a rooster, a dog and a boar. We compared the symbolism, the surface meanings in adages, and the figurative meanings of these animals in Korea and China. As a result, it is found that some are almost the same in usage. However, some are totally different such as expressions related to the animals, the cultural differences and clear understanding. It is necessary to do comparative researches in a detailed and various way by studying the issues derived from verbalism.

• Wind and Structures
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• v.32 no.3
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• pp.239-248
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• 2021

In this study, three airfoil families, NACA, FX and S, in each case three from each series with different shapes were investigated at different angles of attack using Computational Fluid Dynamics (CFD) method. To verify the CFD model, simulation results of the NACA 0012 airfoil was compared against the available experimental data and k-ω SST was used as the turbulence model. Lift coefficients, lift to drag ratios and pressure distributions around airfoils were obtained from the CFD simulations and compared each other. The simulations were performed at three Reynolds numbers, Re=2×105, 1×106and 2×106, and angle of attack was varied between -6 and 12 degrees. According to the results, similar lift coefficient values were obtained for symmetric airfoils reaching their maximum values at similar angles of attack. Maximum lift coefficients were obtained for FX 60-157 and S 4110 airfoils having lift coefficient values around 1.5 at Re=1×106 and 12 degrees of angle of attack. Flow separation occurred close to the leading edge of some airfoils at higher angles of attack, while some other airfoils were more successful in keeping the flow attached on the surface.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.143-149
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• 2000

From the soils of soybean fields in Cotton Branch Station (CBS) and Pine Tree Station (PTS), Arkansas, USA, various single spore isloates of sudden death syndrome (SDS) pathogen were obtained on modified Nash ＆ Snyder's medium (MNSM) with dilution plating technique and transferred to potato dextrose agar (PDA) medium to identify the cultural colony shape. The colony shapes of these isolates resembled F. solani isolate 171 which was white and chalky shaped on MNSM and most of them had unique form of morphology which produced white margin and blue center colony on PDA. Although, some of these isolates had more dark blue or showed slightly different color, all isolates that were selected randomly for green-house inoculation assay produced typical foliar symptoms on leaves of soybean, Hartz 6686. To determine the genetic differences among the isolates, mitochondrial DNA restriction fragment length polymorphism (RFLP) was conducted with fourty isolates from both fields, using mtDNA probes, 2U18 and 4U40, derived from Colletotrichum orbiculare. We obtained distinctive RFLPs in each treatment of restriction enzyme, EcoRI and HaeⅢ. Isolates, 11-2-5 and 14-3-1-1, from CBS and isolates, 104-3-1-2 and 701-1-5-1, from PTS showed different band patterns from 171 in both or in either treatment of restriction enzymes. Even if some of these isolates showed heterogeneous, they were more closer to 171 than PN603. And, also, rest of the thirty-six isolates had exactly same polymorphisms as 171 in each treatment of restriction enzyme. Although, some of the isolates showed the different morphological shape on PDA and slightly different band patterns on RFLPs, all of the isolates selected on MNSM due to their distinctive colony shape from other fungi produced the typical foliar symptoms on soybean leaves in greenhouse inoculation assay. It might be suggested that these isolates were not genetically different from check isolate 171 and they were unique strain of F. solani.

• Korean journal of food and cookery science
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• v.23 no.3 s.99
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• pp.363-368
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• 2007

Jeung-pyun, a very popular fermented rice cake consumed in Korea, consists mainly of rice, rice wine (Tak-Ju), and sugar. The effects of addition of different beans on the quality characteristics of the batter and Jeung-pyun were investigated. Six different beans were mixed with the rice flour at levels of 5% and 10% of the rice flour weight, respectively. The addition of Back-tae, Huk-tae, Sori-tae, which are types of soybeans, and black gram significantly increased the batter volume and viscosity. However, the fermented Back-tae (Cheongguk-jang) was not effective at increasing the batter volume and viscosity. The buffering effect of the beans was very significant on the fermented batter, and the decrease in pH of the fermented batter made with beans was less than that of the control batter without beans. Additions of the soybeans and Cheongguk-jang were most effective for the buffering effect in the fermented batter. Although the Back-tae, Huk tae, and Sori-tae were different colors and shapes, they were all soybeans and exhibited similar effects on the Jeung-pyun batter. However, the effects of the beans were not significant on the Jeung-pyun. The volume and moisture content of the Jeung-pyun made with beans were not significantly different from the volume and moisture of the Jeung-pyun made without beans. The above results suggest that the addition of different soybeans, mung beans, and black gram significantly effects on the properties of Jeung-pyun batter, but not Jeung-pyun itself.