• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.223-226
• /
• 1995

A three-dimensional elastic-plastic finite element analysis using the explicit time integration method has been performed for the characterization of theimpact forming machines. The block upsetting using a forging hammer has been analyzed. The effects of machine type, work capacity of equipment and the mass ratio in an anvil-type hammer have been studied through the analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.5 no.1
• /
• pp.73-83
• /
• 1993

Thermodynamic properties of alternatives for R12 and R22 were estimated and performances of refrigerating cycle using these refrigerants were compared. In this study, we adopt R134a, R22/R142b, R22/R152a, R22/R152a/R124 as alternatives for R12 and R32/R134a for R22. Thermodynamic properties of these refrigerants were estimated using modified CSD equation of state. Cycle simulations of the refrigerating system considering heat source were carried out in order to compare the performance of the system. R134a shows relatively lower COP than R12 but very similar VCR. R22/R142b(50/50 mass fraction), R22/R152a(10/90), R22/R152a/R124(30/25/45) are good for the substitutes of R12 and R32/R134a(30/70) is appropriate for that of R22 in view of COP and VCR.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.23 no.4
• /
• pp.499-509
• /
• 1999

This study was carried out to investigate the effects of wearing disposable diaper with the endothermic agent on thermoregulatory response of infant. Five healthy female infants aged about 5 months were taken as a subject of this experiment. Experimental diapers were six kinds of disposable diaper constructed of nonwoven tissue, fluff pulp, super absorbent polymer, back sheet film, leg elastic, and 0g urea(A) 1g urea(B) , 2g urea(C), 3g urea (D), 4g urea(E) 5g, urea(F) respectively. Urea(98% or over purity) was used as an endothermic agent. Experiment was proceeded while infants were sleeping at 27.5$\pm$0.5$^{\circ}C$, 50$\pm$5% R.H, 0.04m/sec. Each disposable diaper's properties was tested. During the experiment rectal temperature skin temperature of 9 areas temperature inside the disposable diapers were measured, the results were as follows : 1) There was not significant difference among the diapers in absorption capacity retention capacity and rewet(p=0.05). The absorption under load was showed to A, B,

• Journal of Communications and Networks
• /
• v.14 no.3
• /
• pp.286-295
• /
• 2012

To meet the increased demand of video-on-demand (VoD) services, peer-to-peer (P2P) mesh-based multiple video approaches have been recently proposed, where each peer is able to find a video segment interested without resort to the video server. However, they have not considered the constraint of the server's upload bandwidth and the fairness between upload and download amounts at each peer. In this paper, we propose a novel P2P VoD streaming system, named peer cache adaptation (PECAN) where each peer adjusts its cache capacity adaptively to meet the server's upload bandwidth constraint and achieve the fairness. For doing so, we first propose a new cache replacement algorithm that designs the number of caches for a segment to be proportional to its popularity. Second, we mathematically prove that if the cache capacity of a peer is proportional to its segment request rate, the fairness between upload and download amounts at each peer can be achieved. Third, we propose a method that determines each peer's cache capacity adaptively according to the constraint of the server's upload bandwidth. Against the proposed design objective, some selfish peers may not follow our protocol to increase their payoff. To detect such peers, we design a simple distributed reputation and monitoring system. Through simulations, we show that PECAN meets the server upload bandwidth constraint, and achieves the fairness well at each peer. We finally verify that the control overhead in PECAN caused by the search, reputation, and monitoring systems is very small, which is an important factor for real deployment.

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.5
• /
• pp.261-269
• /
• 2016

A high-performance transmit/receive (T/R) switch is essential for every radio-frequency (RF) device. This paper proposes a T/R switch that is designed in the CEDEC 0.13 μm complementary metal-oxide-semiconductor (CMOS) technology for 2.4 GHz ISM-band RF applications. The switch exhibits a 1 dB insertion loss, a 28.6 dB isolation, and a 35.8 dBm power-handling capacity in the transmit mode; meanwhile, for the 1.8 V/0 V control voltages, a 1.1 dB insertion loss and a 19.4 dB isolation were exhibited with an extremely-low power dissipation of 377.14 μW in the receive mode. Besides, the variations of the insertion loss and the isolation of the switch for a temperature change from - 25℃ to 125℃ are 0.019 dB and 0.095 dB, respectively. To obtain a lucrative performance, an active inductor-based resonant circuit, body floating, a transistor W/L optimization, and an isolated CMOS structure were adopted for the switch design. Further, due to the avoidance of bulky inductors and capacitors, a very small chip size of 0.0207 mm² that is the lowest-ever reported chip area for this frequency band was achieved.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.2 no.1
• /
• pp.136-141
• /
• 1998

It is demanded to obtain the design data for bond length of the strengthening carbon fiber sheets. An objectives of this study is to provide preliminary data of rational strengthening design method which is adequate to current domestic status. The present experimental study was performed to evaluate flexural strengthening effects of steel reinforced concrete beams strengthened with carbon fiber sheets. Following conclusions can be extracted. It is revealed that the maximum load carrying capacity is increased up to 9% when the reinforced concrete beams were strengthened with 1-ply of carbon fiber sheet which is half-width of beam. The performance of reinforced concrete sections were improved due to the strengthening carbon fiber sheets on the tensile side of beams. It is believed that the strengthening length of carbon fiber sheets must be provided as (0.5l+3d) to secure the ductile capacity of above three for the flexural strengthening of reinforced concrete beams.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.39 no.4
• /
• pp.271-279
• /
• 2013

Water-soluble collagen (30 wt%) was entrapped within oil phase of lipstick using reversed micelle method to improve the moisture capacity of the lipstick. Reversed micelles containing collagen were prepared using caprylic/capric triglyceride as external phase and polyoxyethylene (10) octylphenyl ether (Triton X-100) and 1-dodecanol as surfactant and co-surfactant, respectively. The formation of reversed micelle encapsulating collagen was confirmed by measuring electric conductivity and UV-vis spectrum using methylene blue (MB). The stability and moisture capacity of the lipstick containing 20 wt% collagen encapsulated reversed micelles were observed by measuring rheology property, moisture content and amino acid content. The molecular ratio (W, water-pool) of water to surfactant (Triton X-100) in the most stable reversed micelle was ${\leq}$ 10. The hardness of the lipstick had no difference with that of the lipstick without reversed micelle, and the moisture content was increased to 59% and the amino acid content was 92.7%.

• Journal of Digital Convergence
• /
• v.12 no.6
• /
• pp.203-213
• /
• 2014

The purpose of this research is to deduce the effects factor of R&D output and outcome in the aspect of the researcher's intellectual property capacity, and conduct an empirical analysis to see if there is intermediated effect between cooperation of a patent attorney and output. I applied three step, input (researcher's intellectual property capacity and intellectual property environment), output (number of patent and SCI paper), outcome (number of technology transfer, profit), and analyzed the effects of researcher's intellectual property factors on output and outcome through structural equation model. The results are as follows. First, there's no cooperation between a researcher and patent attorney, the researcher's knowledge on patent specification had direct effect on the output. Second, a researcher and an patent attorney cooperate, the cooperative activities have complete mediation effect on the output, and the researcher's will to commercialize the technology has direct effects on the output. Third, the intellectual property environment of the research organization gives direct effects on the researcher's intellectual property capacity, and gives indirect effects on the outcome. this study suggest that it is important to cooperate with external experts in order to excellent R&D outcome.

• Journal of the Korea Concrete Institute
• /
• v.23 no.3
• /
• pp.303-310
• /
• 2011

To replace a steel box bridge for constructions of medium span bridges in Korea, the Hybrid Truss Bridge (HTB) is being considered as an alternative bridge type. The core technology of HTB is the connection joint that links the concrete slabs and steel truss pipes. Various construction companies in Japan have developed unique connection systems and applied to the real bridge constructions after verifying their performances through the experimental evaluation. In this study, the fatigue test of a hybrid truss girder has been performed in order to verify the newly proposed hinge type connection joint`s static and fatigue capacities. Through this fatigue test results, it is founded that the structural detail to improve the fatigue capacity should be developed. The hinge connection system with circular ribs has been proposed by means of structural finite element analyses. And then the fatigue test for this connection joint has been performed and it is proved that this connection joint has enough fatigue capacity. Finally, it is expected that the hinge connection system with circular ribs developed by in this study can be easily applied to the real bridge.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.42 no.4
• /
• pp.343-349
• /
• 2016

Many minerals and nutrient salts are abundant in Jeju lava sea water. The objective of this study was to evaluate the skin hydration effects of Jeju lava sea water. The skin barrier serves as a protective barrier that prevents the loss of moisture. The water holding capacity and water transport of the epidermis have been proposed to be important determinants of skin hydration. Jeju lava sea water increased the mRNA expression of filaggrin and caspase-14 which is related to natural moisturizing factor (NMF) formation. Aquaporins 3 (AQP3) are proteins that facilitate the transport of water across cell membranes. Jeju lava sea water increased the mRNA expression and protein expression of AQP3. We employed a skin equivalent model to assess the efficacy of Jeju lava sea water. In a skin equivalent model, Jeju lava sea water increased the CD44 (hyaluronic acid receptor) which is related to skin hydration. From these results, we found out Jeju lava sea water maybe help to skin hydration.