• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.12
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• pp.1083-1090
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• 2015

We designed and manufactured Ka-band SSPA include drive amplifier and high power amplifier MMICs by $0.15{\mu}m$ GaN commercial process. Also, we fabricated main components micro-strip line to WR28 waveguide transition and WR28 wave guide power combiner for Ka-band SSPA. This Ka-band SSPA shows saturated output power 44.2 dBm, power added efficiency 16.6 % and power gain 39.2 dB at 29~31 GHz frequency band.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.3
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• pp.130-144
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• 2013

In this study, we examined the effect of high temperature of urban area on the physiological response of apple tree including the photosynthesis, shoot growth, and fruit quality of 'Fuji'/M.9 apple trees planted at Daegu urban area (DUA) and Gunwi rural area (GRA) for 2 years (2009-2010). During the apple growing season (April-October), the average air temperature of DUA was about $3.0^{\circ}C$ higher than that of GRA and the total rainfall of DUA was 130 mm more than that of GRA. During fruit enlargement stage (June-August), the number of days that recorded daily mean temperature of over $30^{\circ}C$ were ten on DUA in 2010, but there was no day when such temperature was experienced in 2009. Average air temperature of DUA during the maturation stage (September-October) was $19.8^{\circ}C$, which was $4.0^{\circ}C$ higher than that of GRA. The higher temperature of over $30^{\circ}C$ during fruit enlargement stage decreased the photosynthetic rate, shoot growth, fruit weight, and soluble solid content of 'Fuji'/M.9 apple tree. The moderate temperature of about $20^{\circ}C$ during maturation stage increased the photosynthetic rate and soluble solid content of 'Fuji'/M.9 apple tree, but decreased fruit red color. In regional comparison with GRA, photosynthetic rate of DUA was changed from lower before rainy season to higher after rainy season. Fruit weight was higher in DUA than that of GRA. However, fruit weight between DUA and GRA did not show the difference when accumulated days that recorded daily maximum temperature over $35^{\circ}C$ of DUA was increased. Compared to the GRA, soluble solid content of DUA was higher, but fruit red color of DUA was less. These results indicate that the poor red coloring is the most problematic in 'Fuji'/M.9 apple tree by global warming and urbanization.

• Journal of Plant Biotechnology
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• v.8 no.1
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• pp.21-25
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• 2006

Phragmites australis (reed) has received much attention as being one of the principle emergent aquatic plants for treating industrial and civil wastewater. Plant regeneration via plant tissue culture in p. australis was investigated. Three types of callus were identified from seeds on N6 medium plus 4.5 UM 2,4-dichlorophenoxyacetic acid (2,4-D). Yellow compact type showed the best redifferentiation, whereas white compact type and yellow friable were not competent to differentiate into plane. Solid medium culture was better than liquid suspension culture for enhancing callus growth when N6 medium supplemented with 4.5 ${\mu}M$ 2,4-D was used. Phytagel, as a gelling agent, was superior to agar in plant regeneration on N6 medium, supplemented with 9.4 ${\mu}M$ kinetin and 0.54 ${\mu}M$ $\alpha$-naphthaleneacetic acid (NAA). Transfer of the plantlets regenerated from kinetin and NAA-supplemented N6 medium to growth regulator-free MS medium enhanced the further development of the plantlets. Plantlets on subsequently grown to maturity when tansferred to potting soil. The regenerated plants exhibited morphologically normal. The system for plant regeneration of P. australis enables to propagate elite lines on a large scale for water purification in the ecosystem

• Journal of Forest and Environmental Science
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• v.23 no.1
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• pp.5-9
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• 2007

Zygotic embryos just after harvest of seeds were immature globular to heart stage. Maturation of zygotic embryos rapidly proceed when zygotic embryos together with small excised parts of endosperm were cultured on 1/3-strength MS solid medium with 2% sucrose, and the zygotic embryos were germinated within two months. Embryogenic callus was formed from the excised segments of germinating zygotic embryos of Eleutherococcus pedunclus on Murashige and Skoog (MS) medium with $4.5{\mu}M$ 2,4-D. The embryogenic callus formation occurred at a low frequency (less than 7%) from hypocotyl segments. The embryogenic calli were maintained on the same medium as primary medium. High frequency somatic embryogenesis was obtained after the cells were transferred to medium lacking 2,4-D. Cotyledonary embryos were germinated and converted into plantlets on medium with $20{\mu}M$ $GA_3$. Embryogenic callus and somatic embryos were produced spontaneously on the surfaces of roots and/or hypocotyls of plantlets. The frequency of embryogenic callus formation was 85% in roots and 34% in hypocotyls. Therefore maintain of cell lines performed very easily. Plantlets with developed epicotyls at more than 3 cm acclimatized at high frequency (89%). While plantlets with small epicotyls (less than 1 cm) were acclimatized at low rate (32%). The soil survived plantlets produced new sprouts after over wintering in the field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.3
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• pp.165-169
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• 2015

In this paper, in order to develop the composition ceramics with the excellent dielectric properties, $Pb(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_{0.09}(Zr_{0.5}Ti_{0.5})_{0.88}O_3$ ceramics were fabricated by the conventional solid-state method. The effects of ZnO addition on their microstructure and piezoelectric properties were systematically investigated. The rhombohedral-tetragonal phase coexistence has been found in the ceramics without ZnO content and then with further increasing ZnO content, specimens exhibited tetragonal phase. The optimized ZnO content formed liquid phase and aided the grain growth of specimens. When 0.4 wt% ZnO was added, the optimal physical properties ($d_{33}=422pC/N$, $d_{31}=161pC/N$, ${\varepsilon}_r=1,905$, $k_p=0.55$, $Q_m=160$) were obtained.

• Journal of Electrochemical Science and Technology
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• v.5 no.4
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• pp.95-104
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• 2014

Electrochemical performance of Li-ion cells with $LiMn_2O_4$ cathodes and graphite anodes with carbonates electrolytes containing quaternary ammonium-based room temperature ionic liquids (ILs) is investigated. Eight different ILs based on tetraalkylammonium, pyrrolidinium or piperidinium cations paired with bis(trifluoromethylsulfonyl)imide or tris(pentafluoroethyl)trifluorophosphate anions are examined in combination with dimethyl carbonate as a main solvent and fluoroethylene carbonate as a solid electrolyte interface forming agent. It is shown that cycling properties of the cells are strongly affected by the content of ILs in the electrolyte mixtures and its increase corresponds to lower discharge capacity retention. Since viscosity and conductivity of ILs are of a great importance for the electrolytes formulation, some kind of combined parameter should be used for the assessment of IL applicability and calculated values of Walden products for neat ILs represent one of the possible options. Besides, positive effect of ILs on reduction of flammability and enhancement of thermal stability of electrolytes in contact with charged electrodes have been demonstrated by means of self-extinguishing time test and differential scanning calorimetry respectively.

• KSBB Journal
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• v.23 no.2
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• pp.169-176
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• 2008

The concentration of fresh gel from Aloe vera L. by using ulfrafiltration (UF) process was investigated and analyzed. The two membranes (organic and ceramic) with different molecular weight cut-off (MWCO) and modules (flat sheet and tubular) was used. Under optimum operation conditions, ceramic (zirconium dioxide) tubular membrane with MWCO of 50 kDa resulted in higher flux, less fouling, more turbid, higher total solid, higher polysaccharide and less aloin content. Optimum operation conditions were transmembrane pressure of 1.0 bar, feed velocity of 240 L/hr and temperature of $23^{\circ}C$. Volume concentration factor of aloe gel was 3.13 at permeate flux of $51.1\;L/m^2{\cdot}hr$ after processing time of 1.66 hr. Aloin in fresh aloe gel by UF process was effectively removed as permeate and bioactive polysaccharide content was 2.1 times higher than that of fresh aloe gel. These results allowed a very good level of concentration degree and polysaccharide content. Thus, ultrafiltration process of this study was suitable for the concentration of fresh aloe gel though the aloe concentrate showed both the viscosity decrease and partially separation of liquid layer during storage at $4^{\circ}C$.

• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.1028-1033
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• 2010

Wastewater reuse for agricultural irrigation needs treatment and control of pathogens to minimize risks to human health and the environment. In order to evaluate the water quality of UV-treated reclaimed water, this study focused on the relationship between micro-pathogens and particulate matters. MS2 was selected as an index organism because it has similar characteristics to human enteric virus and strong resistance to UV disinfection. The turbidity and suspended solid (SS) were selected for test parameters. In this study, it was performed with different UV doses (30 and $60mJ/cm^2$) for estimation of the MS2 inactivation rate using collimated beam batch experiments in the laboratory. The experiment results by turbidity or SS concentration presented that the increased concentration of them lowered MS2 inactivation. At the turbidity (below 4.27 NTU) and SS (below 1.47 mg/L) of the low level range, the inactivation of 60 UV dose is higher than 30 UV dose. However, at the turbidity and SS of the high level, the increasing UV dose did not show apparent increasing the MS2 inactivation. In quantitative microbial risk assessment (QMRA), it can confirm the trend that $P_D$ and turbidity concentrations have positive correlationship at the low concentration, which was also observed in SS. The QMRA can be helpful in communication with public for safe wastewater reuse and be recommended.

• Food Engineering Progress
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• v.14 no.2
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• pp.118-126
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• 2010

The fibrous material fraction as a by-product from the commercial aloe vera gel processing was obtained and freeze dried. The physicochemical characteristics such as the proximate composition, crystalline/surface structures and several physical functionalities including the water holding capacity (WHC), swelling capacity (SW), oil holding capacity (OHC), emulsion/foam properties and viscosity properties of this powdered sample (100 mesh) were investigated and analyzed by comparison with commercial $\alpha$-cellulose as a reference sample. The total dietary fiber content of powdered sample was very high as much as 87.5%, and the insoluble dietary and soluble dietary fiber content ratios were 77.6 and 22.4%, respectively. The FT-IR spectrum of powdered sample showed a typical polysaccharide property and exhibited a x-ray diffraction pattern for cellulose III and IV like structure. SW (8.24${\pm}$0.15 mL/g), WHC(6.40${\pm}$0.19 g water/g solid) and OHC(10.32${\pm}$0.29 g oil/g solid) of freeze dried aloe cellulose were about 3.3, 1.4 and 2 times higher than those of commercial $\alpha$-cellulose, respectively. Aloe cellulose (~2%, w/v) alone had no foam capacity while improved the foam stability of protein solution (1% albumin+0.5% $CaCl_{2}$) by factor of 300%. Emulsion capacity of 2%(w/v) aloe cellulose was about 70% level of 0.5%(w/v) xanthan gum, but its emulsion stability was about 1.2 times higher than that of xanthan gum. Also, aloe cellulose containing CMC (carboxyl methyl cellulose) of 0.3%(w/v) showed a very good dispersity. Aloe cellulose dispersion of above 1%(w/v) exhibited higher pseudoplasticity and concentration dependence than those of $\alpha$-cellulose dispersion, indicating the viscosity properties for new potential usage such as an excellent thickening agent.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.318-324
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• 2000

Ultrasonic and magnetic resonance imaging systems are used to visualize the interior states of biological objects. These nondestructive methods have many advantages but too much expensive. And they do not give exact color information and may miss some details. If it is allowed to destruct some biological objects to get the interior and exterior information, constructing 3D image from the series of the sliced sectional images gives more useful information with relatively low cost. In this paper, PC based automatic 3D model generator was developed. The system was composed of three modules. One is the object handling and image acquisition module, which feeds and slices objects sequentially and maintains the paraffin cool to be in solid state and captures the sectional image consecutively. The second is the system control and interface module, which controls actuators for feeding, slicing, and image capturing. And the last is the image processing and visualization module, which processes a series of acquired sectional images and generates 3D graphic model. The handling module was composed of the gripper, which grasps and feeds the object and the cutting device, which cuts the object by moving cutting edge forward and backward. Sliced sectional images were acquired and saved in the form of bitmap file. The 3D model was generated to obtain the volumetric information using these 2D sectional image files after being segmented from the background paraffin. Once 3-D model was constructed on the computer, user could manipulate it with various transformation methods such as translation, rotation, scaling including arbitrary sectional view.