• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.33-36
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• 2018

The purpose of this study is to improve the efficiency of anti-pollution film for PV module. The anti-pollution coating process was performed on a glass substrate, which is the same material as the glass substrate for the PV module. We coated the anti-pollution film on the glass substrate by spray coating. After coating process, annealing process was performed during 1 hour at $200^{\circ}C$, $300^{\circ}C$, and $400^{\circ}C$. And then we analyzed the surface characteristics according to the annealing temperature of the film. Annealing process can also improve the durability of the coated film. And then we analyzed the anti-pollution characteristics, particle size of anti-pollution film, light transmittance. The particle size of anti-pollution film was analyzed with FE-SEM. The light transmittance was analyzed with UV-Visible spectroscopy including integrating sphere.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.48.1-48.1
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• 2011

In this presentation, We monitored weather data, such as global irradiance, ambient temperature, temperature of PV module, relative humidity and windspeed for 2 years, for determining accelerated test condition. then, we determined the temperature limit of accelerated test through weather data and FEM analysis. Detailed procedures will be summarized in this work. After analysing outdoor stress such as thermal stress, we decided main failure modes and mechanisms of PV module, especially solder joint of ribbon wire. we carried out the measurement of material properties such as thermal expansion coefficient for planning of accelerated test. we designed accelerated test based on FEM analysis results. we carried out thermal cycling test with 1 cell mini module for 3 months. We monitored the change of electrical performance every 1 week such as Voc, Isc, Pmax, etc. and then, we analized the ribbon wire/electrode intefaces. Detailed results will be summarized in this work.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.12
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• pp.5013-5018
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• 2015

Background: Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders characterized by proliferation of one or more myeloid lineages. Polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) are classical Philadelphia chromosome (Ph)-negative MPN that have a Janus Kinase 2 (JAK2) mutation, especially JAK2V617F in the majority of patients. The major complications of Ph-negative MPNs are thrombosis, hemorrhage, and leukemic transformation. Objective: To study clinical manifestations including symptoms, signs, laboratory findings, and JAK2V617F mutations of Ph-negative MPN (PV, ET and PMF) as well as their complications. Materials and Methods: All Ph-negative MPN (PV, ET and PMF) patients who attended the Hematology Clinic at Maharaj Nakorn Chiang Mai Hospital from January, 1 2003 through December, 31 2013 were retrospectively reviewed for demographic data, clinical characteristics, complete blood count, JAK2V617F mutation analysis, treatment, and complications. Results: One hundred and fifty seven patients were included in the study. They were classified as PV, ET and PMF for 68, 83 and 6 with median ages of 60, 61, and 68 years, respectively. JAK2V617F mutations were detected in 88%, 69%, and 100% of PV, ET and PMF patients. PV had the highest incidence of thrombosis (PV 29%, ET 14%, and PMF 0%) that occurred in both arterial and venous sites whereas PMF had the highest incidence of bleeding (PMF 17%, ET 11%, and PV 7%). During follow up, there was one ET patient that transformed to acute leukemia and five cases that developed thrombosis (three ET and two PV patients). No secondary myelofibrosis and death cases were encountered. Conclusions: Ph-negative MPNs have various clinical manifestations. JAK2V617F mutations are present in the majority of PV, ET, and PMF patients. This study confirmed that thrombosis and bleeding are the most significant complications in patients with Ph-negative MPN.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.36 no.2
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• pp.32-38
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• 2013

In recent years, anti-PID (Potential Induced Degradation) technologies have been studied and developed at various stages throughout the solar value chain from solar cells to systems in an effort to enhance long-term reliability of the photovoltaics (PV) system. Such technologies and applications must bring in profits economically for both manufacturers of solar cell/module and investors of PV systems, simultaneously for the development of the PV industry. In this study two selected anti-PID technologies, ES (modification of emitter structure) and ARC (modification of anti-reflective coating) were compared based on the economic features of both a cell maker with 60MW production capacity and an investor of 1MW PV power plant. As a result of this study, it is shown that ARC anti-PID technology can ensure more profits over ES technology for both the cell manufacturer and the investor of PV power plant.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1217-1226
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• 2015

In a grid-connected photovoltaic (PV) system, the traditional Z-source inverter uses a low frequency transformer to ensure galvanic isolation between the grid and the PV system. In order to combine the advantages of both Z-source inverters and transformerless PV inverters, this paper presents a modified single-phase transformerless Z-source PV grid-connected inverter and a corresponding PWM strategy to eliminate the ground leakage current. By utilizing two reversed-biased diodes, the path for the leakage current is blocked during the shoot-through state. Meanwhile, by turning off an additional switch, the PV array is decoupled from the grid during the freewheeling state. In this paper, the operation principle, PWM strategy and common-mode (CM) characteristic of the modified transformerless Z-source inverter are illustrated. Furthermore, the influence of the junction capacitances of the power switches is analyzed in detail. The total losses of the main electrical components are evaluated and compared. Finally, a theoretical analysis is presented and corroborated by experimental results from a 1-kW laboratory prototype.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.518-522
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• 2001

In recent years, natural energy has attracted growing interest because of environmental concerns. Many studies have been focused on photovoltaic power generation systems because of the ease of use in urban areas. On the conventional system, many photovoltaic modules (PV modules) are connected in series in order to obtain the sufficient DC-bus voltage for generating AC output voltage at the inverter circuit. However, the total generation power on the PV modules sometimes decreases remarkably because of the shadows that partially cover the PV modules. In order to overcome this drawback, an AC module strategy is proposed. On this system, a small power DC-AC utility interactive inverter is mounted on each PV module individually and the inverter operates so as to generate the maximum power from the corresponding PV module. This paper presents a novel flyback-type utility interactive inverter circuit suitable for AC module systems. The feature of the proposed system are, (1) small in volume and light in weight, (2) stable AC current injection, (3) enabling a small DC capacitor. The effectiveness of the proposed system is clarified through the simulation and the experiments.

• KIEAE Journal
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• v.6 no.1
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• pp.25-32
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• 2006

Regarding to the Domestic housing politics to improve residing environment and effective use of country land, apartment buildings have been constructed since early of 1970s. Now apartment is taking over 50% out of entire housing in Korea. In the view point of PV application to the apartment, PV has amny advantages because of the wideness of out-walls and high floors building in APT. Therefore, if APT could use the electricity produced by BIPV, we can solve more easily environment and energy problems caused by housing. The research conclusion by analysing conditions and application method to introduce BIPV application to APT in near future is as below. -The out look of APT has been developed periodically and recently gable roof or canopy is popular which PV installation is more favorable. -For Balcony part with double skin facade sassy window, It has a preferable condition to install on the wall depending on the window direction. -In case of shorter distance between buildings due to high ratio of outside measurement, it is more desirable to install PV on the roof than on the wall of Apartment by considering low solar altitude. -Also depending on the direction of APT building, it is more effective and productive in electricity in the broad surface of side wall of APT. -In case of superhigh floor APT where facade system is mostly double skin facade of curtain wall system, PV module can replace the traditional curtain wall and will reduce architectural materials and obtain various out look design thereof.

• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.152-160
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• 1999

Bacterial population density on soybean leaves was $10^2~10^5CFU/cm^2$. Bacterial population density was increased by progress of plant growth stage. Population density of soybean sprout rotting bacteria on soybean leaves was $0~10^3CFU/cm^2$. Population density of soybean sprouts rotting bacteria was related to cultivating area, but not related to plant growth stage. Cultivar and population density of soybean sprout rotting bacteria were less corelated, and varied by plant growth stages and plant parts. Erwina cypripedii, E. carotovora subsp. carotovora, Xanthomonas campestris pv. glycines, Staphylococcus sp., and Micrococcus sp. were identified as pathogenic bacteria causing soybean sprout rot. In generally population density of E. cypripedii, E. carotovora subsp. carotovora, Micrococcus sp., and X. campestris pv. glycines were high.

• Nuclear Engineering and Technology
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• v.41 no.7
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• pp.969-978
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• 2009

The ASSERT-PV subchannel code developed by AECL has been applied as a design-assist tool to the advanced $CANDU^{(R)1}$ reactor fuel bundle. Based primarily on the $CANFLEX^{(R)2}$ fuel bundle, several geometry changes (such as element sizes and pitch-circle diameters of various element rings) were examined to optimize the dryout power and pressure-drop performances of the new fuel bundle. An experiment was performed to obtain dryout power measurements for verification of the ASSERT-PV code predictions. It was carried out using an electrically heated, Refrigerant-134a cooled, fuel bundle string simulator. The axial power profile of the simulator was uniform, while the radial power profile of the element rings was varied simulating profiles in bundles with various fuel compositions and burn-ups. Dryout power measurements are predicted closely using the ASSERT-PV code, particularly at low flows and low pressures, but are overpredicted at high flows and high pressures. The majority of data shows that dryout powers are underpredicted at low inlet-fluid temperatures but overpredicted at high inlet-fluid temperatures.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2272-2283
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• 2016

This paper proposes a power conditioning system (PCS) for distributed photovoltaic (PV) applications using an asymmetric cascaded multilevel inverter with a single PV source. One of the main disadvantages of the cascaded multilevel inverters in PV systems is the requirement of multiple isolated DC sources. Using multiple PV strings leads to a compromise in either the voltage balance of individual H-bridge cells or the maximum power point tracking (MPPT) operation due to localized variations in atmospheric conditions. The proposed PCS uses a single PV source with a flyback DC-DC converter to facilitate a reduction of the required DC sources and to maintain the voltage balance during MPPT operation. The flyback converter is used to provide input for low-voltage H-bridge cells which processes only 20% of the total power. This helps to minimize the losses occurring in the proposed PCS. Furthermore, transient analyses and controller design for the proposed PCS in both the stand-alone mode and the grid-connection mode are presented. The feasibility of the proposed PCS and its control scheme have been tested using a 1kW hardware prototype and the obtained results are presented.