• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.85-92
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• 2002

This study has been focused on improving transformation efficiency of rice using Agrobacterium tumefaciens. We have demonstrated the effect of this system when the GPAT gene related to the cold-resistance was transferred by Agrobacterium tumefaciens in rice. Transformation conditions were modified using intron $\beta$-glucuronidase (GUS) expression as a reporter gene in the rice. In this study, mature seed-derived calli of rice (Oruza sativa L. cv. Dongjin) were pre-cultured for 3 days and then infected with Agrobacterium. When this infected calli were cultured in the dark for 10 days on co-cu]lure medium containing 50 mg/L of CaCl$_2$, 30 mg/L of acetosyringone, 2 mg/L of 2,4-D, 120 mg/L of betaine, high GUS expression was observed. In the present transformation system, the efficiency of transformation of GPAT gene was about 54%. Stable integration of GPAT gene into chromosomal DNA was proven by southern blot analysis of genomic DNA isolated from T$_{0}$ progenies. The progenies (T1 generation) derived from primary transformant of 5 lines were segregated with a 3 (resistant) : 1 (sensitive ratio) in medium containing hygromycin. This high frequency transformation system can be used as a useful tool in transformation of another monocotyledon.n.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.609-616
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• 2019

When the fouling of a vessel occurs, its resistance at sea increases and there is a corresponding increase in fuel consumption. The maintenance cost of the vessel also increases because it is time-consuming to remove the fouling. To solve this problem and minimize environmental contamination of sea-water, there have been recent developments in anti-fouling paints as self-polishing copolymers that not include toxic elements such as tin. When these conventional techniques are applied to vessels, polishing is promoted during the operation whereby friction or vibration with seawater occurs. This leads to enhanced anti-fouling performance. However, when fouling is intensified such as during an anchorage, there is no flow of seawater and polishing is suppressed. This leads to a deterioration of the performance of anti-fouling. To solve these problems, we developed a system that induces vibration in a vessel during anchorage. As such, the deterioration of polishing due to insuf icient flow of seawater is inhibited. The reliability of the ultrasonic antifouling system was evaluated by calculating its repeatability. The removal efficiency of fouling of the proposed system was qualitatively evaluated using test specimens. The test revealed that the value of the coefficient of variation for the reproducibility of the frequency and amplitude was 0.2 % and 4.0 % on average. The degree of fouling of the specimens was the highest at 73.3 g in the No.5 sepcimen. Moreover, efficiency of fouling removal was 93.2 % on average compared to the specimens without the proposed system.

• Journal of the Korean Ceramic Society
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• v.39 no.9
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• pp.822-828
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• 2002

Fabrication and electrical characterization of R. F. High-power unit capacitors were investigated to study on condition of fabrication processing for R. F. High-power unit capacitor and electrical characteristics according to addition of $ZrO_2$. The unit capacitors were fabricated using tape casting. The optimum mixture ratio of dielectrics and mixing binder for the slurry fabrication was 57.5∼60.0: 42.5∼40.0 wt%. The slurry viscosity was 4000∼5000 cps and casting state of green tape fabricated using these slurry was excellent. Optimum stacking was made by 200 kg/$cm^2$ pressure with 80$^{\circ}C$ heating. $ZrO_2$ was added to improve the electrical characteristics of unit capacitor, especially breakdown characteristics. The dielectric constant and loss factor of the unit condenser having different $ZrO_2$ amounts was not changed in the addition range of 1 to 5 wt%. Also, dielectric constant was not changed in the frequency range of 10 to 500 kHz. It was found that characteristics of resistance voltage was improved through the formation of $CaZrO_3$ and the reduction of particle size as about 3wt% $ZrO_2$ was added.

• Journal of Plant Biotechnology
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• v.41 no.4
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• pp.216-222
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• 2014

This study was carried out to develop an efficient transformation protocol via particle bombardment with PLBs (protocorm-like bodies) in Phalaenopsis. To achieve this aim, osmoticum treatment and an increasing shooting chances in particle bombardment process were applied for this study. In addition, pCAMBIA3301: ORE7 vector which contains a herbicide-resistance bar gene as a selectable marker and ORE7 gene as a gene of interests were employed. With regard to the increasing chances of shooting in particle bombardment, double shooting was the best results with 1.5 ~ 2.5 times higher than those of a single or triple shooting treatment in the productioon of PPT (D-L-phosphinothricin)-resistant PLBs. However, regeneration rate of shoots in double shooting was not high as a single shooting. Further, double shooting showed 35 ~ 40% higher than that of a single shooting in the frequency of browning. Regarding effects of different osmotic treatments, combination of 0.2 M sorbitol with 0.2 M mannitol showed the best results in transformation efficiency, regeneration of transformants and reduction of browning. Putative transgenic Phalaenopsis plants were analyzed by PCR analysis and confirmed the presence of bar and ORE 7 gene. Also, real-time PCR was conducted by using 21 transgenic plants and showed only 4 plants had one copy of transgene; whereas, the other 17 plants had more than 2 copies of transgene. Transgenic phalaenopsis plants produced in this study were transferred to pots and flowered normally without morphological variations in flower and leaf.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.9
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• pp.37-45
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• 1999

For the purpose of reducing the output voltage fluctuation of thin film multijunction thermal converter, EVANOHM alloy-S and chromel-alumel thermocouple were used as a thin film heater material and as a thermoelement of thrmopile, respectively. The temperature coefficient of the resistance of thin film EVANOHM alloy-S heater was about $1.4 {\times} 10^4/^{\circ}C$, which is very small compared to other materials, and thin film chromel-alumel thermocouple showed relatively small difference of the Seebeck coefficients about $38 {\mu}V/K$. The output voltage fluctuation of the thermal converter was about 0.06% for the initial 120 seconds in air and decreased considerably after preheating for 5 minutes or more. The respective AC-DC voltage and current transfer error ranges of the thermal converter were about ${\pm}$1.6 ppm and ${\pm}$0.7 ppm in the frequency range from 10Hz to 10 kHz and increased remarkably below 10 Hz or above 10 kHz.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.12
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• pp.768-775
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• 2017

Energy harvesting characteristics of trapezoidal piezoelectric cantilever generator, which has a lead zirconate titanate (PZT) laminate film, were compared by longitudinal (3-3) and transverse (3-1) modes. The PZT laminate film, fabricated by a conventional tape casting process, was cofired with Ag electrode at $850^{\circ}C$ for 2 h. A multi-layered Ag electrode by a planar pattern and an interdigitated pattern was applied to the PZT laminate to implement the 3-3 and 3-1 modes, respectively. The energy harvesting performance of the 3-3 mode trapezoidal piezoelectric cantilever generator was better than that of the 3-1 mode. An extremely high output power density of $26.7mW/cm^3$ for the 3-3 mode was obtained at a resonant frequency of 145 Hz under a load resistance of $50{\Omega}$ and acceleration of 1.3 G, which is ~3-times higher than that for the 3-1 mode. Therefore, the 3-3 mode is considered significantly efficient for application to high-performance piezoelectric cantilever generator.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.115-116
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• 2012

The demand for flexible electronic systems such as wearable computers, E-paper, and flexible displays has increased due to their advantages of excellent portability, conformal contact with curved surfaces, light weight, and human friendly interfaces over present rigid electronic systems. This seminar introduces three recent progresses that can extend the application of high performance flexible inorganic electronics. The first part of this seminar will introduce a RRAM with a one transistor-one memristor (1T-1M) arrays on flexible substrates. Flexible memory is an essential part of electronics for data processing, storage, and radio frequency (RF) communication and thus a key element to realize such flexible electronic systems. Although several emerging memory technologies, including resistive switching memory, have been proposed, the cell-to-cell interference issue has to be overcome for flexible and high performance nonvolatile memory applications. The cell-to-cell interference between neighbouring memory cells occurs due to leakage current paths through adjacent low resistance state cells and induces not only unnecessary power consumption but also a misreading problem, a fatal obstacle in memory operation. To fabricate a fully functional flexible memory and prevent these unwanted effects, we integrated high performance flexible single crystal silicon transistors with an amorphous titanium oxide (a-TiO2) based memristor to control the logic state of memory. The $8{\times}8$ NOR type 1T-1M RRAM demonstrated the first random access memory operation on flexible substrates by controlling each memory unit cell independently. The second part of the seminar will discuss the flexible GaN LED on LCP substrates for implantable biosensor. Inorganic III-V light emitting diodes (LEDs) have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to conventional incandescent lamps and OLED. However, due to the brittle property of bulk inorganic semiconductor materials, III-V LED limits its applications in the field of high performance flexible electronics. This seminar introduces the first flexible and implantable GaN LED on plastic substrates that is transferred from bulk GaN on Si substrates. The superb properties of the flexible GaN thin film in terms of its wide band gap and high efficiency enable the dramatic extension of not only consumer electronic applications but also the biosensing scale. The flexible white LEDs are demonstrated for the feasibility of using a white light source for future flexible BLU devices. Finally a water-resist and a biocompatible PTFE-coated flexible LED biosensor can detect PSA at a detection limit of 1 ng/mL. These results show that the nitride-based flexible LED can be used as the future flexible display technology and a type of implantable LED biosensor for a therapy tool. The final part of this seminar will introduce a highly efficient and printable BaTiO3 thin film nanogenerator on plastic substrates. Energy harvesting technologies converting external biomechanical energy sources (such as heart beat, blood flow, muscle stretching and animal movements) into electrical energy is recently a highly demanding issue in the materials science community. Herein, we describe procedure suitable for generating and printing a lead-free microstructured BaTiO3 thin film nanogenerator on plastic substrates to overcome limitations appeared in conventional flexible ferroelectric devices. Flexible BaTiO3 thin film nanogenerator was fabricated and the piezoelectric properties and mechanically stability of ferroelectric devices were characterized. From the results, we demonstrate the highly efficient and stable performance of BaTiO3 thin film nanogenerator.

• Journal of Plant Biology
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• v.14 no.4
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• pp.27-33
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• 1971

Information this research an attempt was made to investigate the plant community structure and the process of its formation in the tidal area surrounding Mokpo City the examined area included the stand in Sam-Hak Do wherein sands have inflowed, and the stand in Kat-Ba-Woo which has been left as tidal soil land. Two hundred stands were sampled by making 100m line transects 5m apart and establishing 30cm$\times$30cm quadrates 10m apart on each tape. These data were used to establish frequency, cover degree, density, standing crop (g/$m^2$), contained Cl in the soil, and pH. Results of the research are as following: 1. There were 25 species of plants in the stands from Sam-Hak Do, 18 in the stands from Kat-Ba-Woo, and so 28 species in all. Regardings the importance value, the rank of dominant species is Salicornia herbacea L., Suaeda maritima Dumorties, Diplachne fusca L., Echinochola hispidula Nakai, Cyperus iria L., Setaria lutescens Hubbard in Sam-Hak Do, and Suaeda maritima Dumorties, Echinochloa hispidula Nakai, Aster tripolium L., Scripus maritimus L., Salicornia herbacea L., Diplachne fusca L., in the lands from Kat-Ba-Woo. Among them are five kinds of halophytes Salicornia herbacea L., Suaeda maritima Dumorties, Atriplex Gmelini C.A. Meyer, Aster tripolium L., and Limonium tetragonum Bullock; and two Kinds of naturalized plants Diplachan fusca L., Aster subulata. M. In the stands from Sam-Hak Do there was evidence of a secondary succession phenomena in the presence of Cyperaceae such as Cyperus liria L., Juncus decipiens Nakai, and Fimbristylis longispica Steudal, which could not be found in the stands from Kat-Ba-Woo. 2. On the number of species of vegetation, the further inland from the floodgate the higher the number; that is, the lower the content of Cl the higher the number of species. 3. On the distribution of the vegetation; comparing DFD index and Cl content, the main plants are Salicornia herbacea L., Suaeda maritima Dumorties, Atriplex gmelini C.A. Meyer, Diplachne fuscal, Echinochola hispidula Nakai where the Cl content of soil is more than 13.2%. 4. On the standing crop; Salicornia herbacea L., which has high resistance to salt, was half the total was production of 1090/$m^2$ while Suaeda maritima Dumorties was 1/4, Diplachne fusca L. 1/8, and Echinochloa the least. Analyzing the result, the research indicates that the main factor in plant community formation in tidal land is tolerance for Cl, and that a plan for utilizing the halophytes which are abundant in tidal land should be devised.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.175-182
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• 1995

Rice is one of the most successful monocot in regenerating fertile and genetically stable transgenic plants. However there is no report of a rice line developed in Korea that can be used for regeneration of fertile and genetically stable transformants. In this paper we first demonstrate that a Korean variety Nakdongbyeo, is suitable to obtain transgenic rice plants. Protoplasts from embryogenic suspension cultures were co-transformed with HPT (hygromycin phosphotransferase) and GUS ($\beta$-glucuronidase) genes in separate plasmids in the presence of PEG (polyethylene glycol). In 5 independent experiment, the average frequency of calli showing hygromycin resistance were 1.73%. Plantlets were regenerated from the Hy $g^{R}$ calli. The average efficiency of plantlet regeneration was apprbximately 27%. Based on the GUS activities of hygromycin resistant calli, ca.35% of the resistant calli carried active GUS genes. The R0 transgenic plantlets were grown to maturity and Rl seeds were obtained. By examining the in siぉ activity of GUS in Rl seeds and seedlings, we confirmed that the GUS transgene driven by a CaMV 35S (cauliflower mosaic virus) promoter showed proper expression patterns. We also confirmed Mendelian segregation of the HPT transgene in the Rl generation.n.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.373-383
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• 2019

The objectives of this study were to compare the protein expression patterns and degrees and identify the protein function of disomic addition lines (DAs) in Leymus racemosus, in order to improve the quality of wheat. Upon SDS-PAGE, L. racemosus showed two major protein bands whereas Chinese Spring (CS) had four major protein bands of high molecular weight. The DA(s) generally showed a similar protein expression pattern to that of CS, because 42 chromosomes were from CS and two chromosomes were from L. racemosus. However, only the L.r[J] line showed two protein bands of between 15 and 20 kDa, like L. racemosus. Image analysis based on 2-DE revealed that L.r[F] had the most upregulated protein spots, whereas L.r[N] had the least upregulated protein spots. For L.r[I], the frequency of the downregulated protein spots was higher than that of the upregulated ones. Using MALDI-TOF MS, the protein function was identified for each protein spot on the 2-DE polyacrylamide gel. The protein spots were classified into 11 groups according to protein function. Among the 11 groups, most protein spots of the DA(s) were identified as proteins related to metabolism. Additionally, unique protein spots of the DA(s) were related to abiotic stressors such as cold and heat. Those proteins are useful for improving wheat quality with resistance against abiotic stressors.