• Journal of agricultural medicine and community health
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• v.8 no.1
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• pp.44-65
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• 1983

As a part of the epidemiological studies of clonorchiasis, this study was conducted to evaluate the current endemicity and the natural transition of the Clonorchis infection in Gimhae Gun and delta area a high endemic area in Korea in recent years, prior to the introduction of praziquantel which will eventually influence the status of the prevalence. The data obtained in this study in 1983 were evaluated for natural transition of the infection in comparison with those obtained 16 years ago in 1967 by the author(Kim, 1974). The areas of investigation, villages and schools surveyed, methods and techniques used in this study were the same as in 1967, except for the contents of the questionnaire for raw freshwater fish consumption by the local inhabitants. 1) The prevalence rate of clonorchiasis in the general population of the villages was 48.1% on the average out of a total of 484 persons examined. The average of those of the riverside-delta area was 65.2% and 43.0% in the inland area. Among the schoolchildren, the prevalence rate was 8.2% on the average out of a total of 1,423 examined. By area, the prevalence rate was 10.8% in the riverside delta area and 2.8% in the inland area. By sex, difference in the prevalence was seen only in the inhabitants of the inland area showing 52.4% in the male and 33.5% in the female. 2) In the natural transition of the infection, the prevalence rate among the inhabitants has decreased from 68.8% in 1967 to 48.1% in 1983, and in the schoolchildren from 56.4% in 1967 to 8.2% in 1983. The reduction rate was higher in the riverside-delta area than in the inland area. 3) In the prevalence rate by age, 11.9% was first seen in the 5-9 age group and the rate gradually increased up to 75.0% in the 50-59 age group. By sex, the rate was higher in the male than in the female in the 20-29 age group and over. 4) In the natural transition of the prevalence rate by age, the reduction rate of the infection during the past 16 years was greater in the younger age groups up to the 40-49 age group and reached the same level in the age group 50-59. Reduction was seen again in the age group over 60s. By sex, the reduction rate was greater in the female than in the male in the 20-29 age group and over. By area, the reduction rate was greater in the riverside delta area than in the inland area, particularly in the young age groups. 5) In the intensity of the infection among the cases, the mean egg out-put per mg feces per infected cases(EPmg) in the inhabitants was 6.3. EPmg of those of the river-side-delta area was 15.4 and that of the in-land was 2.8. On the other hand, in the schoolchildren, EPmg was 3.2, and no difference was seen between the two areas, the river-side-delta area and the inland area. 6) In the transition of the intensity of the infection by area, EPmg among the inhabitants inexplically increased from 7.8 in 1967 to 15.4 in 1983. This was probably caused by uneven specimen collection in the process of sampling the population. EPmg of the inhabitants in the inland area and those of the schoolchildren of both riverside delta and inland areas showed a similar decrease in the past 16 years. 7) The intensity of the infection by age showed a relatively low level in the 20-29 age group and below, and EPmg 5.1-9.5 was seen in the 30-39 age group and over. Sex, Epmg was 5.8 in the male and 4.7 the female. By in 8) In the transition of the intensity of the infection, EPmg decreased from 6.2 in 1967 to 5.4 in 1983. By age, in contrast to the figures of 1967 in which EPmg gradually increased with some fluctuation from 1.1 in the 0-4 age group to peak 10.5 in the 50-59 age group, in 1983 lower intensity of the infection was seen in the age group from 10-14 to 20-29 with the EPmg range of 0.6-2.7. 9) In the distribution of the clonorchiasis cases by the range of EPmg value, 43.2% of the cases were in 0.1 0.9 and 34.6% in 1.0-4.9. As a whole by cumulative percent, 44.6% of them were under 0.9 as light infection and 86.1% of them under 9.9 up to moderate infection. By sex, no difference was seen in Epmg. 10) In the transition of the distribution by the range of Epmg, the cases were distributed up to the range 80.0-99.9 in 1967 and to 60.0-79.9 in 1983. By cumulative percent, in the range of 0.1-0.9 and less, light infection, 34.3% of them were distributed in 1967 and 44.6% in 1983 with about 10% increase. In the range of 5.0-9.9 and less, up to moderate infection, 83.2% in 1967 and 86.1% in 1983 of the cases were seen, respectively. 11) The practice of raw freshwater fish consumption among the inhabitants seems to have decreased in recent years. Those who admitted to raw freshwater fish consumption in the last two years among the infected inhabitants were 59.3%, although 86.8% of them professed to have experience with raw freshwater fish consumption. 31.7% of those who have had experience of the raw freshwater fish consumption denied any further consumption in recent years. From an interview of 543 school-children, 24.1% of them admitted to an experience of raw freshwater fish consumption. However, those who have practised in the past two years comprized 17.9%. Those who denied raw freshwater fish consumption in recent years among those who had such experience were 26.0% out of 131 interviewed. The rate of raw freshwater fish consumption in both inhabitants and schoolchildren were higher in the male than in the female. On the contrary, the rate of those who did not practise in recent years among those who had experience of raw freshwater fish consumption was higher in the female than in the male. 12) The major reason for the reduction of raw freshwater fish consumption among the local inhabitants was the risk of the fluke infection. However, it has become apparent that such change of taste has resulted from water pollution impact which has affected throughout the areas of the freshwater systems in this locality since last several years. 13) In animal survey, Clonorchis infection was seen in 14.8% of 88 dogs examined and 3.7% of 27 house rats examined. It was noted that populations of dogs and cats have increased in the villages surveyed. Although the prevalence rate was lower in the present survey than those of 1967, the significance of the animals as the reservoir host has not changed. 14) Prevalence rate of Clonorchis infection by cercariae in the first intermediate host, Parafossarulus manchouricus, was 0.6% out of 517 snails examined. The infection rate was lower in comparison with 2.3% out of 2,124 examined in 1967. Moreover, sharp decreases in number and distribution of the intermediate host snails in many watershed areas of the huge freshwater systems in this locality seemed to reduce transmission of Clonorchis in connection with the intermediate host stage of its life cycle. 15) Clonorchis infection in the second intermediate fish hosts was relatively low. The mean number of Clonorchis metacercaria per fish in Pseudorasbora parva was 517 in 1983, whereas it was 1943 in 1968 through 1969. Environmental water pollution has also caused the decreased fish population density in these areas, and this has also apparently affected to the practice of raw freshwater fish consumption among the local inhabitants. 16) In conclusion, endemicity of Clonorchis infection in Gimhae Gum and delta area of the Nagdong River has sharply decreased during the past 16 years. The major cause of the regressive transition of the infection was the water pollution of the land water systems of this locality. The pollution has upset the ecosystems comprizing of the intermediate hosts of Clonorchis in many areas, and also affected to a significant extent to the discontinuance of the local inhabitants for raw freshwater fish consumption.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.56-62
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• 2013

We present a rectifier for wireless power transmission using multiplier configuration in layout for MOSFETs which works at 13.56 MHz, designed to fit in CMOS process where conventionally used diodes are replaced with the cross-coupled MOSFETs. Full bridge rectifier structure without comparators is employed to reduce current consumption and to be working up to higher frequency. Multiplier configuration designed in layout reduces time delay originated from parasitic series resistance and shunt capacitance at each finger due to long connecting layout, leading to fast transition from on-state to off-state cross-coupled circuit structure and vice versa. The power conversion efficiency is significantly increased due to this fast transition time. The rectifier is fabricated in $0.11{\mu}m$ CMOS process, RF to DC power conversion efficiency is measured as 86.4% at the peak, and this good efficiency is maintained up to 600 MHz, which is, to our best knowledge, the highest frequency based on cross-coupled configuration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.1
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• pp.53-60
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• 2010

This paper presents a novel gain control system composed of a feedback circuit, Two stage Low Noise Amplifier (LNA) using 0.18 um CMOS technology for 5.2 GHz. The feedback circuit consists of the seven function blocks: peak detector, comparator, ADC, IVE(Initial Voltage Elimination) circuit, switch, storage, and current controller. We focus on detecting signal and designing storage circuit that store the previous state. The power consumption of the feedback circuit in the system can be reduced without sacrificing the gain by inserting the storage circuit. The adaptive front-end system with the feedback circuit exhibits 11.39~22.74 dB gain, and has excellent noise performance at high gain mode. Variable gain LNA consumes 5.68~6.75 mW from a 1.8 V supply voltage.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.345-351
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• 2016

This study was carried out to determine an optimal lean $NO_x$ trap (LNT) regeneration condition based on a $NO_x$ storage fraction. The LNT regeneration was performed by an in-cylinder post fuel injection method. A $NO_x$ storage fraction is defined by the ratio of current cumulated $NO_x$ amount in the LNT to the $NO_x$ storage capacity: 0 means empty and 1 fully loaded. In this study five engine operating conditions were chosen to represent the New European Driving Cycle. With various $NO_x$ storage fractions each engine operating condition, the LNT regeneration was executed and then $NO_x$ conversion efficiency, additional fuel consumption, CO and THC slip, peak catalyst temperature were measured. The results showed that there exist an optimal condition to regenerate the LNT, eg. 1500 rpm 6 bar BMEP with below 0.7 $NO_x$ storage fraction in this experimental constraint.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.214-217
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• 2003

The connectorless power supply system on that multi-contact causes confidence when the wiring reconstructed in the rear. As you see above, contact points between sets and indoor space cause inferior function of audio frequency so it needs to be eliminated. This paper explains the structure of connectorless power supply to supply the system with power crossing the air gap in the part of inductively in the connectorless power supply of both magnetic and electrical model. To get maximum output of electrical load, compensating capacitor compensates to show inter-inductance, lequeage-inductance reducing the track-inductance and access the conditions for resonance. At that time it accesses the maximum electric power. The small change of the value of compensating capacitor causes the changes of maximum electric power. Here the power electronics technology is used not only in the industrial machinery but also in the home appliances so the switching power supply is used to actualize the miniaturization, lightweight, and high efficiency. Generally the condenser input methods are widely used in the rectification circuit of switching power supply, but condenser input method generate great quantity of high frequency components because with this method the current flows in the power input filtering condenser only around value of peak of ac input voltage. To solve these problems, installation of power factor improve circuit on the front of filtering capacitence was considered. Several methods were suggested regarding, but the active filter method which makes smalliging and highly power factor possible are the produce main stream. IC for power factor improvement can be utilized by CMOS process proposing low power consumption. When the high power factor is considered seriously in the power factor improvement circuit, active filter method is selected. In the active filter method, the boost converter is used. Regarding this ·the boost converter is needed.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.31-39
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• 2012

In this paper, we propose a microprocessor-based automatic voltage regulator(AVR) to reduce consumers' electric energy consumption and to help controlling peak demanding power. Hybrid Switching Automatic Voltage Regulator (HS-AVR) consist of a toroidal core, several tap control switches, display and command control parts. The coil forms an autotransformer which has a serial main winding and four parallel auxiliary windings. It controls the output voltage by changing the combination of the coils and the switches. Relays are adopted as the link switches of the coils to minimize the loss. To make connecting and disconnecting time accurate, relays of the circuit have parallel TRIACs. A software phase locked loop(PLL) has been used to synchronize the timings of the switches to the voltage waveform. The software PLL informs the input voltage zero-crossing and positive/negative peak timing. The traditional voltage transformers and AVRs have a disadvantage of having a large mandatory capacity to accommodate maximum inrush current to avoid the switch contact damage. But we propose a suitable AVR for every purpose in smart grid with reduced size and increased efficiency.

• Animal Bioscience
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• v.37 no.3
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• pp.500-508
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• 2024

Objective: Due to current selection practices for increased egg production and peak persistency, the production profile, age at maturity, and body weight criteria for commercial layers are constantly changing. Body weight and age at the time of photostimulation will thus always be the factors that need to be adequately addressed among various production systems. The current study was carried out to determine the effects of pullets' body weight (low, medium, and heavy) on their performance, welfare, physiological response, and hormonal profile. Methods: With regard to live weight, 150 16-week-old pullets were divided into three groups using a completely randomized design (CRD) and held until the 50th week. One-way analysis of variance was used to evaluate the data under the CRD, and the least significant difference test was used to distinguish between treatment means. Results: In comparison to the medium and light birds, the heavy birds had higher body weight at maturity, an earlier age at maturity, and higher egg weight, eggshell weight, eggshell thickness, egg yolk index, breaking strength, egg surface area, egg shape index, egg volume, and hormonal profile except corticosterone. However, the medium and light birds had lower feed consumption rates per dozen eggs and per kilogram of egg mass than the heavy birds. Light birds showed greater body weight gain, egg production, and egg specific gravity than the other categories. At 20 weeks of age, physiological response, welfare aspects, and catalase were non-significant; however, at 50 weeks of age, all these factors-aside from catalase-were extremely significant. Conclusion: The findings of this study indicate that layers can function at lower body weights during photostimulation; hence, dietary regimens that result in lighter pullets may be preferable. Additionally, the welfare of the birds was not compromised by the lighter weight group.

• Journal of Fashion Business
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• v.9 no.6
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• pp.160-174
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• 2005

Despite the decrease in the number of children due to low birth rate, the domestic children's apparel market has been achieving steady growth as family income is rising thanks to more opportunities for working women, parents spend more on their children, and they prefer brand products that make their children look special. In addition, the market is suffering from hard competition as large enterprises have joined the race. The present study purposed to survey the children's apparel market in Korea, which is in a transitional period, and to contribute to the development of the market with Korean brands. For this purpose, we analyzed the characteristics of children's apparel brands in the 21st century based on the current state of the domestic children's apparel market and, based on the findings, forecasted the future trend of children's apparel brands, suggested improvements for expected problems, proposed standards for coping with changes such as diversification, high quality and differentiation in the children's apparel market, and provided consumers with information on how to purchase products. According to the result of analyzing the characteristics of children's apparel brands in the 21st century, brands are categorized largely into four types - life cultural brands, functional product brands, character brands and brands advancing to China. Life cultural brands equipped with all necessities for children are expanding, and with the deepening social problems of environmental pollution and the reduction of the child population, functional products made of environment-friendly materials are spreading widely, targeting infants and children. Furthermore, for extending age targets and diversifying products, children's apparel is using characters. The use of characters is expected to have a considerable effect on the growth of brands because children are more subjective as consumers than before and they are more easily persuaded with characters. Domestic children's apparel brands advancing to China have a high expectation of success in overcoming the limitation of the local market that has reached its peak and growing into global brands. Korean apparel makers are struggling to overcome the depressed domestic market, to recover consumers' consumption, to cope with market opening, to pursue high value of sensibility and to expand the seniors' market, etc. In this situation, future trends of children's apparel brands will be the expansion of family brands, brand totalization, quality price, niche market (pre-teen market), etc. In response to these trends, we made the following suggestions for improvement. 1. Children's apparel brands are evolving into family brands as well as into total brands through voluming. Today, however, apparel makers are advancing to the children's apparel market with the concept of adults' apparel and, as a result, children's apparel is merely adults' apparel of reduced size, having problems in design, color and materials. Thus, apparel makers must develop design considering the wide range of size and the characteristics of children's apparel, strengthen sourcing abilities to create revenues, and make thorough survey of customers to find common denominators between adults' apparel and children's apparel considering that characteristic that the target class is different from the buyer class. Furthermore, they must make active investments in human resources, develop outstanding products through advanced planning and design, and support marketing techniques and management systems to stores. 2. As the declining birth rate will continue to have a negative effect on the market, it may be difficult to expand the market size but there is still a margin for growth through high-sensibility and high-quality products. The competitiveness of brands is determined by their market shares. Accordingly, concepts should be specialized according to lifestyle, customers' diverse needs should be satisfied, and cross-coordination should be achieved within a brand. 3. Considering Korean parents who do not spare investment in their children despite shrinking consumption, functional products must be high value-added goods that can enhance efficiency. However, in the current situation of the infants' apparel industry where a textile manufacturer supply its products to multiple brands, it is difficult to develop unique products only based on materials. Thus, it is considered urgent to appeal to consumers not by relying on materials only but by finding methods of applying their own characters to children's dress.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.52-57
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• 2010

Although chemical sedimentation and ion exchange are usually applied to the treatment of heavy metal ions and radioactive cations, they have some serious disadvantages like a great consumption of chemicals, the disposal of valuable metals, and the secondary pollution of soil by the solid-waste. The advanced countries recently have studied the electrochemical ion exchange, combined electrochemical reduction and ion exchange, for the development of the alternative technique. This study has been performed to investigate the optimum condition for the preparation of the nickel hexacyanoferrate (NiHCNFe) which is an electrochemical ion exchanger. NiHCNFe film was deposited on the surface of nickel plate by chemical method or electrochemical method. The morphology and composition of NiHCNFe were observed by SEM and EDS, respectively. The peak current density of NiHCNFe was measured from the cyclic voltammograms of the continuous oxidation-reduction reaction in a parallel plane ion exchange electrode reactor. It was found that the chemical preparation method was better than the electrochemical method. The concentrated NiHCNFe was apparently deposited on nickel plate when dipping in the preparing solution for 118 h, especially. It also had a best durable performance as an ion exchange electrode.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.1
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• pp.34-48
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• 1982

1. Production and consumption of chemical fertilizers in Korea could be divided into five different phases of total imports, setting up fertilizer plants, self-sufficiency in production, net export, and diversification in compound fertilizers. Currently the nation has production capacity of 800 thousand M/T of nitrogen, 400 thousand M/T of phosphate ($P_2O_5$) and 200 thousand M/T of potash ($K_2O$). 2. Yearly consumption increased every year, since 1964, 28,000 M/T N, 7,700 M/T $P_2O_5$, and 7,500 M/T $K_2O$ until 1972, when the increase jumped by eight times for $P_2O_5$ and seven times for $K_2O$ for the following 3 years in anticipation of their short supply. Now total consumption has been more or less stabilized at the level of 450 thousand M/T N, 220 thousand M/T $P_2O_5$ and 180 thousand M/T $K_2O$ for the last 7 years. 3. Current operation rate of fertilizer plants is around 80% throughout the whole industry, after going through several different levels depending on demand at times. 4. Fertilizer export started in 1967 and reached a peak of 150 thousand nutrient ton in 1972, about 20% of total production, before temporarily stopping due to over-demand for next three years. The export resumed again in 1976 rise to the all time high of 670 thousand nutrient ton in 1980, almost half of total production, and then started to decline due to higher price of petroleum since then. 5. The decline in fertilizer export appears to be accelerated because several countries, in South-Eastern Asia, traditional export market for Korean fertilizers, started to build their own plants, since 1980, based on their raw materials of especially petroleum. 6. Current consumption in Korea is about 30 nutrient Kg per 10a, equivalent to that in Western European countries, partly due to new high-yielding rice varieties and extensive cultivation of fruit trees and vegetables. Additional fertilizer demand in future can be anticipated in reclaimed land for growing grass and forestry.