• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.418-421
• /
• 2009

Renewable energy or green energy is a hot issue in theses days. Since wind resource can be endlessly supplied by nature, researchers and common people are interested in study how to use that resource at home or company. Especially, many architects have tried to integrate wind power generator for a part of building. So in this paper, three buildings installed wind power turbine are targed to CFD analysis and these buildings are Bahrain trade center, Discovery tower, and Pearl river tower. Bahrain trade center is the first builidng installed real wind turbine, Discovery tower is constructing at Texas, and Pearl river tower is designed and proved by china researchers. These buildings have very different type of wind power turbine and each turbine has different conditions for best power generation. Therefor this paper will focus on characteristic shape of buildings, wind power turbine type, and expected purpose of construction. Moreover, CFD analysis will show wind flow pattern and wind speed while wind is passing through wind turbine of three tall buildings. CFD analysis for three buildings make comparison the wind flow patterns with experimental result.

• Journal of fish pathology
• /
• v.25 no.2
• /
• pp.77-84
• /
• 2012

Various antibiotics, that could induce the appearance of resistant microorganisms, have been used for treatment or prevention of bacterial diseases in marine and ornamental fish. We determined and characterized the level of antibiotic-resistant bacteria and proportion of multi-drug resistant bacteria in intestinal microflora of both marine fish cultured in Korea and imported ornamental freshwater fish. For this the bacterial species and resistance to antibiotics were investigated in intestine of rock bream Oplegnathus fasciatus cultured in Korea and pearl gourami Trichogaster leeri imported from Singapore to characterise. Although the bacterial species were different, proportions of resistant bacteria to single antibiotics or multi-drug were higher in intestinal microflora of pearl gourami Trichogaster leeri imported from Singapore than in rock bream Oplegnathus fasciatus cultured in Korea. These results indicate that various antibiotics have been being used before trading without measures in the market of asian ornamental fishes, providing high risks for the emergence of multi-drug resistant bacteria.

• Korean Journal of Microbiology
• /
• v.37 no.1
• /
• pp.21-27
• /
• 2001

Recently many investigators have devoted considerable attention to the production and purification of PA for antigens, and the preparation of new synthetic medium (RM medium) have solved to increase the yields of the PA but, the low sensitivity of the PA to detect B. anthracis infections has remained as a problem to be solved. This study was undertaken to evaluate the yields of the PA from culture filtrates of B. anthracis Sterne $34F_2$ strain in modified RM medium in which 10 g/l of $NaHCO_3$ and 10g/l of glucose were replaced by 8 g/l and 5 g/l, and the first purification step of PA from culture broth was used hydroxyapatite. The PA was purified by hydroxyapatite column chromatography, DEAE-Sepharose CL-4B column chromatography and Toyo-pearl gel filtration chromatography. The yield of PA from the modified RM medium, 8.6 mg/l.

• Journal of Power Electronics
• /
• v.15 no.1
• /
• pp.202-215
• /
• 2015

This paper investigates the stability and performance of model predictive controlled active-front-end (AFE) rectifiers for energy storage systems, which has been increasingly applied in power distribution sectors and in renewable energy sources to ensure an uninterruptable power supply. The model predictive control (MPC) algorithm utilizes the discrete behavior of power converters to determine appropriate switching states by defining a cost function. The stability of the MPC algorithm is analyzed with the discrete z-domain response and the nonlinear simulation model. The results confirms that the control method of the active-front-end (AFE) rectifier is stable, and that is operates with an infinite gain margin and a very fast dynamic response. Moreover, the performance of the MPC controlled AFE rectifier is verified with a 3.0 kW experimental system. This shows that the MPC controlled AFE rectifier operates with a unity power factor, an acceptable THD (4.0 %) level for the input current and a very low DC voltage ripple. Finally, an efficiency comparison is performed between the MPC and the VOC-based PWM controllers for AFE rectifiers. This comparison demonstrates the effectiveness of the MPC controller.

• Journal of Power Electronics
• /
• v.18 no.1
• /
• pp.277-288
• /
• 2018

Wireless inductive power transfer (IPT) technology is used in many applications today. A compact and high-frequency primary side inverter is one of the most important parts of a WPT system. In this study, a modified class EF-type voltage-fed multi-resonant inverter has been proposed for WPT application at a frequency range of 85-100 kHz. Instead of an infinite input choke inductor, a resonant inductor is used to reduce loss and power density. The peak voltage stress across the MOSFET has been reduced to almost 60% from a class-E inverter using a passive clamping circuit. A simple yet effective design procedure has been presented to calculate the various component values of the proposed inverter. The overall system is simulated using MATLAB/SimPowerSystem to verify the theoretical concepts. A 500-W prototype was built and tested to validate the simulated results. The inverter exhibited 90% efficiency at nearly perfect alignment condition, and efficiency reduced gradually with the misalignment of WPT coils. The proposed inverter maintains zero-voltage switching (ZVS) during considerable load changes and possesses all the inherent advantages of class E-type inverters.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.10 no.2
• /
• pp.77-83
• /
• 1990

A three year's field experiment was carried out on newly reclaimed tidal saline soils to evaluate the salt tolerance and growht characteristics, and their relationship to dry matter production and nutrient quality of main selected pasture species. Nine temperate grasses (14 varieties) and two forage crops (sorghum and pearl millet) were grown under different mulching treatments with medium sand and red-yellow soils (fine loamy materials of Typic Hapludults) from 1986 to 1988. Tall wheatgrass, tall fescue, reed canarygrass and alfalfa showed a good tolerance to soil salinity, especially tall wheatgrass (cv. Alkar) produced 19.6 ton/ha dry matter yield annualy under mulching treatment with medium sand depth in lcm. Pearl millet (cv. Gahi-3) was also evaluated as a salt tolerable forage species. Under salt stress in newly reclaimed tidal lands, plant showed a decrease in the assimirable leaf area (LA) as well as specific leaf area (SP. LA) and a low leaf weight ratio(LWR), and it resulted in a low concentration of crude protein and low digestible dry matter contents. Absorption of macro and micro elements in the plant on tidal lands was increased markedly.

• International Journal of Advanced Culture Technology
• /
• v.9 no.3
• /
• pp.34-45
• /
• 2021

On February 18, 2019, the Chinese government officially released the Outline of the Development Plan for the Guangdong-Hong Kong-Macao Greater Bay Area, which will lead the country in a new round of reform and opening-up. The Greater Bay Area will become a dynamic world-class city cluster, an international scientific and technological innovation center with global influence, an important support for the development of the "One Belt And One Road", a demonstration area for in-depth cooperation between the mainland and Hong Kong and Macao, and a high-quality living area for living, working and traveling. Non-Pearl River Delta(Non-PRD) cities in Guangdong Province are adjacent to the Guangdong-Hong Kong-Macao Greater Bay Area, so it is of practical significance to promote the high-quality development of urban tourism from an international perspective. Based on the panel data released in Guangdong Yearbook 2019, this paper uses the envelopment data analysis (DEA) method to explore ways to promote the high-quality tourism development of Non-PRD cities in Guangdong Province based on the perspective of international development.

• Journal of the Economic Geographical Society of Korea
• /
• v.14 no.3
• /
• pp.407-418
• /
• 2011

The southern region including Guangzhou(黃州), the capital of Guangdong Province, was called "South of the Mountain Range" (嶺南) because it is located south of the Five Mountain Ranges (五嶺) which made mobility difficult prior to unification of China by Qin dynasty (秦) in 221 BCE. The Guangdong region of the South of the Mountain Range (嶺南) was an administratively independent unit and, as such, called the Nanyue kingdom (南越國). This is the origin of the Chinese character "yue", and terms such as yueyu (Cantonese), yuecai (Cantonese cuisine), yueju (Cantonese opera) are still in use today. Guangzhou, called Panyu (番禹) during the Nanyue kingdom period, was settled early in the northern part of the Pearl River (珠江, Zhu Jiang) delta. It became the first port to open its doors to the great powers of the West during the Qing period. Although it has now fallen behind Shanghai which developed later, Guangzhou is still the third largest city after Beijing and Shanghai, and thus, it is an influential open coastal city. Today, not only is Guangzhou the world center of the light textile industry, it also spurs development in various manufacturing industries. Along with nearby Hong Kong, Macao, and Shenzhen, it plays the role of cradle of the Pearl River delta economic zone. Firmly established early on as the greatest central city in southern China, Guangzhou is simultaneously a hub in various aspects such as regional politics, economics, and culture; it was also the center of revolution and resistance which attempted to challenge the northern political powers. Guangzhou is known for the history of the rise and fall of its port, but with developmental efforts, it still maintains its influence. Guangzhou's dynamic development of today brings with it issues such as the environment and moral system which must be dealt with.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.43 no.1
• /
• pp.54-62
• /
• 2010

With the aim of developing and indoor overwintering technique for Pearl oyster, Pinctada fucata martensii, the metabolic rates of young oysters (52.4-83.0 mm in shell length) were measured for 2 weeks at water temperatures of 8, 10, 12, and $14^{\circ}C$. The filtration rate (FR) ranged 0 to $4.84\;L\;h^{-1}gDW^{-1}$ (mean, $0.02{\pm}0.06 $ to $3.12{\pm}1.45$), with significant changes observed over thme except for the case of a water temperature of $14^{\circ}C$. Respiration rate (R) ranged from 0 to $2.370\;mgO2\;h^{-1}gDW^{-1}$ (mean, 0 to $1.77{\pm}0.37$), with significant respiratory disorders observed at temperatures below $12^{\circ}C$; in contrast, the rate increased on the $14^th$ day of the experiment in the case of a temperature of 14$^{\circ}C$. No significant difference was observed among the different water temperatures in terms of excretion rate (E) or absorption efficiency (Abs.eff), except for a significant decrease in aerobic metabolism in the case of water temperature of $8^{\circ}C$. The estimated scope for growth (SFG) ranged from -9.1 to $126.9\;J\;h^{-1}gDW^{-1}$ (mean. $-4.1{\pm}2.6$ to $82.85{\pm}42.6$). A significant energy Joss was found at $8^{\circ}C$, with negative SFG observed throughout the experiment and a gradual energy decrease observed over time at water temperatures of $10^{\circ}C$ and 120C. However. SFG remained positive throughout the experiment in the case of $14^{\circ}C$. The estimated minimum energy requirement, assessed from energy expenditure, is $8.00-34.24\;J\;h^{-1}gDW^{-1}$ (mean, $17.67{\pm}6.17$). In conclusion, the lowest temperature suitable for indoor overwintering is above $14^{\circ}C$.

• Korean Journal of Agricultural Science
• /
• v.3 no.1
• /
• pp.31-37
• /
• 1976

These studies were carried out to find out the most reasonable planting density and :adequate amount of nitrogen fertilizer for the pearl barley. and results obtained are summarized as follows; 1. The planting densities affected neither the heading date nor the maturing date of p. earl barley. 2. The planting density of 90cm X (30cm+30cm) was the most adequate for high yield and that of $40cm{\times}20cm$ which was the most densely planted plot in this experiment showed the lowest grain yield. 3. The height and weight of stem were significantly increased by increased fertilization of nitrogen. 4. The highest grain yield per 10a (613kg/10a) was resulted from the nitrogen fertilization of 20kg/10a. and the plot of which amount of nitrogen fertilization was 15kg/10a showed the grain yield of 603kg per 10a. But there was not significant difference between two plots mentioned above. 5. Single plant per hill was the most effective for high yield of pearl barley and 3 plants per hill dropped the grain yield of 28.4%.