• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.05a
• /
• pp.75-76
• /
• 2016

Even if ICS(Interference Cancellation System) repeater is used in wireless communication system, it has the disadvantage that it must have enough distance between Donor and Service antenna to be isolated. In this paper, new ICS repeater integrated antenna with high insolation characteristics is designed. The proposed antenna is fabricated for 800MHz and measured. Bandwidth and gain are optimized by changing the stub lengths near main patch and power divider, and also by changing the size of parasitic patch. This antenna has a return loss less than -13 dB, a gain over 3 dBi, and an isolation between the donor and the server antennas less than -56 dB from 824~894 MHz for CDMA mobile communication. Therefore, the proposed antenna structure can be applied to eliminate the shadow area and to expand the coverage area for any other wireless communication bands.

• Parasites, Hosts and Diseases
• /
• v.57 no.2
• /
• pp.191-195
• /
• 2019

Trypanosomiasis is caused by a pathogenic protozoan of the genus Trypanosoma, being Trypanosoma vivax the most important agent for cattle. The aim of the present study was to demonstrate the expansion of T. vivax infection in different mesoregions of Minas Gerais, Brazil, and describe the clinicopathological findings of trypanosomiasis in cattle. The diagnosis was based on visualization of the parasite in blood smears and DNA detection of T. vivax in the blood of live cows and tissues of necropsied animals by the polymerase chain reaction (PCR). Thirty suspected herds were tested, of which 11 were positive for T. vivax. The most frequent clinical signs were anemia, apathy, drop in milk production, weight loss, reproductive disorders, and nervous signs. Concomitant diseases, such as malignant edema, pneumonia and increased cases of mastitis were associated with T. vivax infection. Three cows were necropsied and the most significant findings were low body condition score, pale mucous and spleen with white pulp hyperplasia. The results demonstrated the expansion of T. vivax infection in Minas Gerais, that PCR-associated blood smears are promising for diagnosis, and that other diseases often occur concomitantly to T. vivax infection in regions with trypanosomiasis in cattle.

• Journal of Advanced Navigation Technology
• /
• v.23 no.2
• /
• pp.166-171
• /
• 2019

This paper has designed a current mode class D power amplifier to increase the transmission efficiency of a 6.78 MHz wireless power transfer (WPT) transmitter and to ensure stable characteristics even when the transmitting and receiving coil intervals change. By reducing the loss due to the parasitic capacitor component of the transistor, which limits the theoretical efficiency of the linear amplifier, this research has improved the efficiency of the power amplifier. The circuit design simulator was used to design the high efficiency amplifier, and the power output and efficiency characteristics according to the load impedance change have been simulated and verified. In the simulation, 42.1 dBm output and 95% efficiency was designed at DC bias 30 V. The power amplifier was fabricated and showed 91% efficiency at the output of 42.1 dBm (16 W). The transmitting and receiving coils were fabricated for wireless power transfer of the drone, and the maximum power added efficiency was 88% and the output power was $42.1dBm{\pm}1.7dB$ according to the load change causing from the coil intervals.

• Journal of Animal Science and Technology
• /
• v.60 no.4
• /
• pp.9.1-9.11
• /
• 2018

Background: In recent years, with the prohibition of antibiotics used as growth stimulants in the nutrition of farm animals, researchers have searched for alternative natural and reliable products in order to be able to sustain the developments experienced during the use of antibiotics and to overcome the possible inconveniences. In this context, studies on evaluation of essential oils in poultry nutrition have been reported to improve the utilization of feed, stimulate the release of digestive enzymes, increase absorption in the stomach and intestines, antimicrobial and anti-parasitic effects and thus, can be an alternative to antibiotics and improve meat quality as well. Indeed, this study has been carried out to explore the effects of the addition of 150 mg/kg capsicum oleoresin (CAP), carvacrol (CAR), cinnamaldehyde (CIN) or their mixture (CAP+CAR+CIN) into the broilers' ration over sensory, physical and chemical properties in breast meat and leg meat. Methods: Experiments were conducted over 400 male and female broiler chicks (Ross-308) in 5 groups (1 control group and 4 treatment groups), each composed of 80 chicks. The control group was fed without feed additives while the second, third, fourth and the fifth groups were fed with 150 mg CAP/kg feed, 150 mg CAR/kg feed, 150 mg CIN/kg feed, and 150 mg CAP+CAR+CIN/kg feed, respectively. Results: Addition of CAP, CAR, CIN or CAP+CAR+CIN had effects on the sensory (of taste, tenderness, juiciness and overall acceptability); physical properties (of $L^*$ value and toughness), the chemical properties (of DM, CF, CP, linoleic, EPA, behenic, MUFA, PUFA and ${\Sigma}n-6$ of the leg meat), the physical characteristics (of toughness and firmness), and the chemical properties (of CF, CP, linoleic, ecosenic, EPA, lignoseric, MUFA and ${\Sigma}n-3$) of the breast meat in comparison to control group. Furthermore, while the treatments had positive impacts on thawing loss, cooking loss and water holding capacity in both breast and leg meat; no effect was observed on pH value and lipid oxidation on day 1, day 4 and day 8. Conclusion: The results strongly suggested that the addition of CAP, CAR, CIN or CAP+CAR+CIN to the rations of the broiler chicks changed the sensory, physical and chemical properties of breast and leg meat. It was also observed that these compounds were more effective when they were added to the ratio as a mixture rather than adding them individually.

• Research in Plant Disease
• /
• v.23 no.2
• /
• pp.114-149
• /
• 2017

World-wide crop loss caused by insect pest and nematode reaches critical level. In Korea, similar crop loss has been gradually augmented in the field and greenhouse due to continuous crop rotation. The current methods on controlling herbivorous insects and plant parasitic nematodes are mostly depended on agro-chemicals that have resulted additional side-effect including occurrence of resistant insects and nematodes, environmental contamination, and accumulation in human body. To overcome the pitfalls, microbe-based control method have been introduced and applied for several decades. Here, we revised biological control using by the bacteria, fungi, and virus in order to kill insect and nematode and to attenuate its virulence mechanism. The introduced microbes mainly secreted out the hydrolysing enzymes and toxic compounds to target host membrane or cell wall directly. Indirectly, the microbe-triggered plant innate immunity against insects and nematodes was also reported. In conclusion, we provide a new frontier of microbe-based environmentally friendly procedure and effective methods to manage insects and nematodes.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.16
• /
• pp.6825-6830
• /
• 2015

Opisthorchis viverrini is remains a public health problem in Thailand, particularly in the northeast and north regions which have the highest incidences of chonalgiocarcinoma (CCA). O. viverrini causes the disease opithorchiasis, and its has been classified as a group 1 biological carcinogen. Humans, dogs, and cats become infected with O. viverrini by ingesting raw or undercooked fish containing infective metacercariae. The first human cases of O. viverrini infection were reported in Thailand 100 years ago, and it's still a problem at the community level. Based on data for the year 2009, more than 6 million people were infected with O. viverrini. Associated medical care and loss of wages in Thailand costs about $120 million annually. This review highlights the current status of O. viverrini infection in communities of Thailand through active surveillance for the five years period from 2010 and 2015. A total of 17 community-based surveys were conducted, most in the northeast region. Some 7 surveys demonstrated a high prevalence over 20%, and the highest was 45.7%. Most commonly infection was found in age group of 35 years and older, males, and agricultural workers. Although, the national prevalence may be decreasing but the results show that the O. viverrini infection is still high in communities of the northeast region. Therefore, the focus in populations living in northeast Thailand should be screening of infection and changing their eating behavior.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.64-64
• /
• 2015

Control of plasma processing methodologies can only occur by obtaining a thorough understanding of the physical and chemical properties of plasmas. However, all plasma processes are currently used in the industry with an incomplete understanding of the coupled chemical and physical properties of the plasma involved. Thus, they are often 'non-predictive' and hence it is not possible to alter the manufacturing process without the risk of considerable product loss. Only a more comprehensive understanding of such processes will allow models of such plasmas to be constructed that in turn can be used to design the next generation of plasma reactors. Developing such models and gaining a detailed understanding of the physical and chemical mechanisms within plasma systems is intricately linked to our knowledge of the key interactions within the plasma and thus the status of the database for characterizing electron, ion and photon interactions with those atomic and molecular species within the plasma and knowledge of both the cross-sections and reaction rates for such collisions, both in the gaseous phase and on the surfaces of the plasma reactor. The compilation of databases required for understanding most plasmas remains inadequate. The spectroscopic database required for monitoring both technological and fusion plasmas and thence deriving fundamental quantities such as chemical composition, neutral, electron and ion temperatures is incomplete with several gaps in our knowledge of many molecular spectra, particularly for radicals and excited (vibrational and electronic) species. However, the compilation of fundamental atomic and molecular data required for such plasma databases is rarely a coherent, planned research program, instead it is a parasitic process. The plasma community is a rapacious user of atomic and molecular data but is increasingly faced with a deficit of data necessary to both interpret observations and build models that can be used to develop the next-generation plasma tools that will continue the scientific and technological progress of the late 20th and early 21st century. It is therefore necessary to both compile and curate the A&M data we do have and thence identify missing data needed by the plasma community (and other user communities). Such data may then be acquired using a mixture of benchmarking experiments and theoretical formalisms. However, equally important is the need for the scientific/technological community to recognize the need to support the value of such databases and the underlying fundamental A&M that populates them. This must be conveyed to funders who are currently attracted to more apparent high-profile projects.

• Journal of fish pathology
• /
• v.4 no.2
• /
• pp.87-94
• /
• 1991

In the late summer of 1990 and 1991, mass mortality occured among cage-cultured grouper, Epinephelus septemfasciatus in south cost of Korea. The moribund fish didn't feed and became pale or dark chestnut colour and irregularly swimmed due to the loss of equilibrium, finally the diseased fish fell down side away on the bottom or the surface of cage showing the bent of body and died. The diseased fish showed the extensive hemorrahge in brain, the swelling of spleen and bile duct as the specific syptoms of internal organs. So the gill, skin and other organs of the diseased fish were examined for the presence of pathogenic parasites and bacteria. The parasitic Trichodina sp. were detected only from the gill lamella of the diseased fish, but these parasites seemed to be not a direct causative agents that induced the gross mortality of the cultured grouper. because these parasites were also observed in normal grouper, yellowtail, red seabream and rock bream co-cultured with the diseased grouper in same or near cages. In the viral examination, although isolation of the causative agent by the use of estabilshed cell Lines, RTG-2 and CHSE-214, was not succeed, the normal grouper inoculated intramuscularly with the filtered homogenate of the organs of the diseased fish showed the same external and internal signs with the naturally infected grouper. They died within a week. By using the naturally and the artificially infected fishes, electron microscopic observation revealed numerous hexagonal or polygonal particles in the cytoplasm of liver cells. Based on the these results, we suggest that the mass mortality of the cultured grouper would be occurred by the infection of a viral agent.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.5
• /
• pp.473-480
• /
• 2011

The proton exchange membrane (PEM) fuel cell system is critically dependent on the humidity, which should be properly maintained over the entire operating range. A membrane humidifier is used for the water management in the PEMFC because of the membrane humidifier's reliable performance and zero parasitic power loss. In the PEMFC system, the membrane humidifier is required to provide appropriate humidity for the design point of the fuel cell. Although the performance of the fuel cell depends on the performance of the humidifier, few studies have provided a systematic analysis of the humidifier. We carry out an experimental analysis of the membrane humidifier using a vapor condensation bottle. The dry air pressure, water flow temperature, and air flow rate were chosen as the operating parameters. The results show that the time constant for the dynamic response of the membrane humidifier is relatively short, but additional analysis should be carried out.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.1
• /
• pp.8-18
• /
• 2000

We presented a BGA(Ball Grid Array) package for RF circuit modules and extracted its electrical parameters. As the frequency of RF system devices increases, the effect of its electrical parasitics in the wireless communication system requires new structure of RF circuit modules because of its needs to be considered of electrical performance for minimization and module mobility. RF circuit modules with BGA packages can provide some advantages such as minimization, shorter circuit routing, and noise improvement by reducing electrical noise affected to analog and digital mixed circuits, etc. We constructed a BGA package of ITS(Intelligent Transportation System) RF module and measured electrical parameters with a TDR(Time Domain Reflectometry) equipment and compared its electrical parasitic parameters with PCB RF circuits. With a BGA substrate of 3${\times}$3 input and output terminals, we have found that self capacitance of BGA solder ball is 68.6fF, and self inductance 146pH, whose values were reduced to 34% and 47% of the value of QFP package structure. S11 parameter measurement with a HP4396B Network Analyzer showed the resonance frequency of 1.55GHz and the loss of 0.26dB. Routing length of the substrate was reduced to 39.8mm. Thus, we may improve electrical performance when we use BGA package structures in the design of RF circuit modules.