• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.1016-1019
• /
• 2005

In the cutting of plate steel, the quality of the cut surfaces is strongly dependent on the cutting condition such as cutting speed, plate thickness, power, kerf width and gas pressure etc. The cutting tests of Steel Automobile Press Hot were carried out using $CO_2$ Laser cutting machine. The kerf width and surface roughness of a section are examined at various cutting conditions. This paper deals with cutting characteristics of Steel Automobile Press Hot(SAPH400) using $CO_2$ Laser Cutting Machine.

• Korean Journal of Materials Research
• /
• v.17 no.8
• /
• pp.447-451
• /
• 2007

We investigated the dependence of the various annealing conditions and thickness ($6\sim45nm$) of the Ti-doped $Al_2O_3$ coating on the electrochemical properties and the capacity fading of Ti-doped $Al_2O_3$ coated $LiCoO_2$ films. The Ti-doped-$Al_2O_3$-coating layer and the cathode films were deposited on $Al_2O_3$ plate substrates by RF-magnetron sputter. Microstructural and electrochemical properties of Ti-doped-$Al_2O_3$-coated $LiCoO_2$ films were investigated by transmission electron microscopy (TEM) and a dc four-point probe method, respectively. The cycling performance of Ti-doped $Al_2O_3$ coated $LiCoO_2$ film was improved at higher cut-off voltage. But it has different electrochemical properties with various annealing conditions. They were related on the microstructure, surface morphology and the interface condition. Suppression of Li-ion migration is dominant at the coating thickness >24.nm during charge/discharge processes. It is due to the electrochemically passive nature of the Ti-doped $Al_2O_3$ films. The sample be made up of Ti-doped $Al_2O_3$ coated on annealed $LiCoO_2$ film with additional annealing at $400^{\circ}C$ had good adhesion between coating layer and cathode films. This sample showed the best capacity retention of $\sim92%$ with a charge cut off of 4.5 V after 50 cycles. The Ti-doped $Al_2O_3$ film was an amorphous phase and it has a higher electrical conductivity than that of the $Al_2O_3$ film. Therefore, the Ti-doped $Al_2O_3$ coated improved the cycle performance and the capacity retention at high voltage (4.5 V) of $LiCoO_2$ films.

• Membrane Journal
• /
• v.22 no.4
• /
• pp.251-257
• /
• 2012

For the separation and recovery of n-pentane from nitrogen environment, the poly (dimethyl siloxane) (PDMS) composite membranes supported by polyetherimide (PEI) hollow fiber membranes were prepared. To characterize the gas separation properties of the resulting membranes, the permeance of n-pentane and nitrogen, concentrations of permeate and retentate, and recovery ratio were measured for n-pentane and nitrogen mixtures. The permeance of n-pentane and nitrogen, 2485.3 and 9.9 GPU, were observed respectively. As the stage cut decreases and the feed concentration increases, the n-pentane concentration in permeate tends to increase. In the meanwhile, the recovery efficiency tends to increase as the stage cut increases and the feed concentration decreases.

• Korean Journal of Food Science and Technology
• /
• v.32 no.3
• /
• pp.659-667
• /
• 2000

Quality attributes of fresh-cut green onion(Allium fistulosum L.) as affected by rinsing and packaging were investigated in terms of flesh weight, color, viable cell counts, sensory properties during storage at $10^{\circ}C$. Fresh green onions were trimmed, cut, and rinsed with cold water(approximately $5^{\circ}C$) as well as chlorine solution(100 mg/L) and then packaged in low density polyethylene film pouches of $63\;{\mu}m$ thickness. Rinsing treatments with cold water or chlorine solution did not significantly influence changes in microbial populations but sensory characteristics, resulting in cut green onions of better visual quality as compared to the control without rinsing. Fresh-cut green onions were also rinsed with cold water and packaged in sealed bags of low density polyethylene films with different thickness(22, 36, $63\;{\mu}m$), and stored at $10^{\circ}C$ for 18 days. Thickness of polyethylene film was a significant factor for microorganisms populations and sensory attributes. Mesophilic aerobic bacterial count after 13 days for the control, packed in punched film bags, was $3.07{\times}10^6}$ CFU/g, while those for samples in hermetically sealed bags ranged only $1.74{\sim}2.02{\times}10^5}$ CFU/g. Gas composition within the sealed packages changed from normal air to about $1.3{\sim}5.4%\;O_2$ and $4.0{\sim}8.0%\;CO_2$ after 13 days of storage. Particularly, the visual sensory quality of cut green onion samples was retained better in polyethylene film bags of $63\;{\mu}m$ thickness(gas transmission rate: 600 $O_2\;mL/day{\cdot}m^2{\cdot}atm;\;2,500\;CO_2\;mL/day{\cdot}m^2{\cdot}atm$) than in the others.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.21 no.11
• /
• pp.1029-1035
• /
• 2008

$LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ cathode materials prepared from different precursors in lithium rechargeable batteries were characterized by various analytical methods. $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ powders were synthesized by using solid-state reaction method and their physical and chemical properties were analyzed by XRD, SEM, particle size analyzer and TCP-AES. These materials showed different crystallinity, particle size, surface morphology and chemical composition. Also, the charge/discharge cycling of $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ electrodes was carried out under various cut-off voltages and it showed different behaviors. It was found that the electrochemical cyclability of $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ was strongly related to its crystallinity.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.13 no.1
• /
• pp.47-56
• /
• 2010

The main objectives of this comparative study were 1) to quantify the potential contribution of wood chips to revegetation on the cut slope in a constructed area, 2) to compare the floristic similarity of species composition whether existing of wood chips in the soil media or not. Wood chips were combined with soil media in the ratio of 30%. The thin layer (1 cm, 3 cm) soil media revegetation methods and the thick layer (10 cm) soil media revegetation method were constructed on the cut slopes by machineries respectively. Also, comparative experiments the existence of wood chips in the soil media were conducted to evaluate the effects of wood chips on revegetation works. The total size of quadrat was $300m^2$ ($100m^2{\times}3$). The results of monitoring for 3 years on cut slopes were as follows: 1) All the quadrat existed in the proper range for vegetation. 2) Species richness of quadrat including wood chips was 10% more than those of commercial soil medias. 3) The coverage rates of quadrat including wood chips were similar or superior to those of conventional methods. It can be concluded that the use of wood chips would be effective to promote establishment of diverse landscape and vegetation. However, it behooves to continue monitoring on succession of vegetation for ecological restoration. Finally, adequate wood chips deposit and gathering methods should be studied properly.

• The Korean Journal of Community Living Science
• /
• v.21 no.1
• /
• pp.71-79
• /
• 2010

This study was conducted to develop fresh-cut and processed pears. After treatment of citric acid (1%) or N-acetylcysteine (0.2 M), and co-treatment of citric acid (1%) and N-acetylcysteine (0.2 M) into the pears c.v. 'Wonhwang', the quality changes of pears during cold storage ($1^{\circ}C$) for 10 days were investigated respectively. Pear quality and the taste of pears increased much more in those treated with anti-browning agents than those in the control group at 10 days after anti-browning treatment and cold storage. Changes in Hunter b values of pears treated with 0.2 M N-acetylcysteine were insignificant. Those with Polyphenol oxidase (PPO) activity and ethylene production were had the most decreased effects and those with the phenolics compound contents were the most lowered. Firmness of fruits increased in treatment of 0.2 M N-acetylcysteine + 1% citric acid solution. The amount of respiration decreased in the application of 1% citric acid solution. Consequently, fruit freshness can be maintained more effectively by the treatment of the anti-browning agent compared to non-treatment, even if the effectiveness were different among different kinds of anti-browning agents.

• Proceedings of the KAIS Fall Conference
• /
• 2010.11a
• /
• pp.92-95
• /
• 2010

본 논문에서는 2차원 영상을 3차원 영상으로 변환하여 입체감을 주는 방법을 제안하였다. 2D/3D 변환을 위해 Normalized Cut을 사용하여 객체를 분할하였고, 분할된 객체에 Optical Flow 값을 계산해 깊이정보를 생성하여 입체감을 주었다. 객체를 분할하기 위해 Normalized Cut을 이용한 방법에 Optical Flow를 이용한 가중치 값을 추가하여 정확한 객체 분할을 하였고, 처리속도 향상을 위해 영상의 밝기, 색상을 고려한 Watershed 알고리즘을 적용하여 연산량을 줄였다. 분할된 영상에 Optical Flow를 이용하여 색상 정보의 차이를 통해 객체별 고유벡터 값을 연산하여 객체의 움직임 정보를 추출하고 운동시차를 고려해 깊이 정보를 생성하였다. 제안한 방법으로 변환하기 위해 MATLAB을 사용하였다. 제안한 변환 방법은 2D/3D 입체변환에 효과적이었다.

• Proceedings of the KWS Conference
• /
• 2009.11a
• /
• pp.55-55
• /
• 2009

FGB(Flexible Glasswool Backing) Submerged Arc Welding has been one of the main welding processes for one side butt welding in shipbuilding industries, which can efficiently improve the welding productivity by the addition of a supplementary filler metal into the molten weld pool. As recent ships have become larger in size, the application of high tensile and higher grade of steels has been continuously increased. Single pass FGB SA welding process accompanies such a high heat input when welding thick plates that the mechanical properties of weld metal can be dramatically degraded. This study has been performed in order to obtain high toughness and tensile properties of high heat input FGB SA welds, and to evaluate the effect of alloy elements on their mechanical properties. To complete welding 25mm-thick EH36 grade steel plate by single pass, 1.2mm diameter and 1.0mm long cut wires has been distributed in the groove before welding, and three different test coupons have been made using C-1.5%Mn, C-1.8%Mn-0.5%Mo, and C-1.4%Mn-1.7%Ni cut wires to investigate the influence of nickel(Ni) and molybdenum(Mo) on the mechanical properties of welds. Test results showed that the addition of Ni and Mo effectively promotes the formation of Acicular Ferrite(AF), while significantly reducing the amount of Grain Boundary Ferrite(GBF) in weld metal microstructures, which resulted in a beneficial effect on low temperature impact toughness and strength.

• Journal of Korean Society of Forest Science
• /
• v.105 no.3
• /
• pp.275-283
• /
• 2016

The objective of this study was to examine carbon dynamics with biomass, soil $CO_2$ efflux, litter and root decomposition after tree density control in young Pinus densiflora stands. The stands were established with 50% thinning, clear-cut, and control stands with three pseudo-replicated plots and a bare soil plot in 8-year-old Pinus densiflora nursery field. Monthly measurements were conducted from March 2012 to February 2014 and aboveground biomass and coarse-roots were estimated by derived allometric equations. Average diameter growth at root collar in control and thinned was 0.89 cm and 1.48 cm per year, respectively, and the diameter growth of control stand was significantly higher than that of thinned stands (p<0.05). Total biomass was estimated to 5.17, $4.85kg\;C\;m^{-2}$ per year in control and thinned, respectively. Annual soil $CO_2$ efflux in control, thinned, clear cut, and bare soil was 3.71, 3.90, 4.17, $4.56kg\;CO_2\;m^{-2}\;yr^{-1}$, respectively and removing trees significantly increased soil $CO_2$ efflux (p<0.05). Net Ecosystem Production (NEP) was 1.57, 1.36, -0.67, $-1.25kg\;C\;m^{-2}\;yr^{-1}$ in control, thinned, clear cut and bare soil in the young Pinus densiflora stands. NEP was significantly decreased by removing trees. Thinning increased diameter at root collar and carbon of individual tree and recovered 86% of carbon removed by thinning after one-year. In addition, soil $CO_2$ efflux increased and NEP increased by thinning. Results of this study, tree density control such as thinning increased the carbon storage and growth of the young Pinus densiflora stands.