• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.641-646
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• 2024

This paper is studied for the design and experiment of a wideband printed 1x2 dipole array antenna for 3.5GHz band application. The printed dipole antenna used in the array antenna was implemented in the form of a rectangular strip, and was consisted with a broadside coupled stripline (BCS). The feed line was designed to be tapered for broadband impedance matching. As a result of comparing the simulation results and measurement results, it was found that the two results were in good agreement with 2.8% error(100MHz shift @3.5GHz). As a result of the experiment, based on VSWR=2, a bandwidth of about 16% was obtained from the center frequency of 3.5 GHz to 3.15~3.70 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.144-150
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• 2012

In this paper, circularly polarization patch array antenna of RSE(Road-side Equipment) base station for DSRC(Dedicated Short Range Communication) of ITS(Intelligent Transport System) is proposed. The antenna of RSE base station for DSRC is designed to operate circularly polarization to receive reflected signal from multiplex path effectively. The proposed antenna consisted of microstrip patch and feed line, the slit is inserted in the proximity of the slot of feed structure to generate circularly polarization. The $2{\times}2$ array structure is designed to satisfying gain that DSRC RSE base station antenna required. Measured impedance bandwidth and axial-ratio bandwidth are satisfied by all DSRC band of 5.795~5.855 GHz. Vertical and horizontal HPBW of the proposed antenna are both about 43 degrees, it showed gain characteristic of about 11.21 dBi.

• Analytical Science and Technology
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• v.12 no.6
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• pp.528-533
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• 1999

The total iodine is determined in serum, fresh milk and feed additive by ICP-MS. The preparation involves only a 25-fold dilution with a diluent by direct nebulization in the plasma. The diluent composition is $NH_4OH$(0.5% v/v)+$CH_3OH$(5% v/v) and the abundance of iodine is measured at m/z=127. The calibration curve was linear over the ranges $0-100{\mu}g/L$ with $R^2=0.99$ for iodine. The detection limit of this method is $0.084{\mu}g/L$ for iodine. The relative error range of milk powder SRM in optimum condition is 2.30%-4.73%. The concentration ranges of iodine in the serum, fresh milk, feed additive were $12.4-40.2{\mu}g/L$, < 0.01-3.11 mg/L, < $10^{-7}-2.60g/kg$ respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.7
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• pp.1009-1014
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• 2012

Environmental stress boosts the levels of stress hormones and accelerates energy expenditure which subsequently imbalance the body's homeostasis. L-ascorbic acid (L-AA) has been recognized to mitigate the negative impact of environmental stress on production performances in birds. The present investigation was carried out to elucidate the effect of different dietary levels of L-AA on production performance, egg quality traits and fertility in Japanese quail at low ambient temperature. Sixty matured females (15 wks) were equally divided into three groups (20/group) based on the different dietary levels of L-AA (0, 250 and 500 ppm) and coupled with an equal number of males (1:1) obtained from the same hatch. They were managed in uniform husbandry conditions without restriction of feed and water at 14 h photo-schedule. Except for feed efficiency, body weight change, feed consumption and hen-day egg production were recorded highest in 500 ppm L-AA supplemented groups. Among the all egg quality traits studied, only specific gravity, shell weight and thickness differed significantly (p<0.05) in the present study. Fertility was improved significantly ($p{\leq}0.01$) to a dose dependent manner of L-AA. The findings of the present study concluded that dietary L-AA can be a caring management practice at least in part to alleviate the adverse effect of cold induced stress on production performance in Japanese quail.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.5
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• pp.671-674
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• 2002

This study investigated the use of multinutrient blocks (MNB) composed of 35% date syrup, 35% date syrup byproducts, 10% date fronds, 7% urea, 7% cement and 6% common salt for growing small ruminants, as partial substitute for the roughage component of the diet (Rhodes grass hay) and its effect on feedlot performance and economics of feeding. Eight growing local Omani goats and 8 sheep (each about one year old) were used in this study. Mean body weights for goats and sheep (kg), respectively were $21.1{\pm}4.5$ and $25.5{\pm}4.1$. The goats and sheep were subdivided into two sub-groups of more or less equal body weights for each species. Each sub-group in both species was either fed on 0.5 kg concentrate+ad libitum Rhodes grass hay or the same diet+restricted hay (about 0.2 kg/head/day) and ad libitum amount of MNB. Sheep significantly (p<0.05) consumed greater amounts of MNB ($36{\pm}17$g/head/day) than goats ($6{\pm}2.5$ g/head/day). Feeding of the MNB was effective in sparing about 40% of the roughage Rhodes grass hay for goats (from 240 to 140 g) and about 42% for sheep (from 252 to 146 g) or approximately 100 g/head/day for both goats and sheep. This reduction (or sparing) in the consumption of Rhodes grass hay was coupled by an improvement in daily liveweight gain (g/head/day) in both goats (from 29 to 46 by 58.6%) and sheep (from 26 to 39 by 50%) and also by an improvement in the feed conversion efficiency (g feed/g gain) of both goats (from 25 to 13.8 by 45%) and sheep (from 28.7 to 17.2 by 40%). Cost of daily consumed feeds as well as cost/kg gain (or cost of meat) were both reduced due to feeding of MNB. They were both respectively reduced by 7.5% (from 53 Baisa/day to 49) and 38% (from 1,828 Baisa/kg to 1,140). It was economically viable to feed MNBs containing date by-products and urea to small ruminants in the Sultanate of Oman.

• Animal Bioscience
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• v.37 no.4_spc
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• pp.719-729
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• 2024

Global pig production has increased by 140% since the 1960s. The increase in global population, coupled with improving socioeconomic conditions of many countries has led to an increased consumption of meat globally, including pork. To keep up with demand and capitalize on economic opportunities, the countries of China, the United States (US), and the European Union (EU) have become the top 3 pork producers globally. China is of particular interest, as it is the both the largest country in pork production and pig numbers, as well as being the largest importer of pork from other countries. Globally, the efficiency of pork production has improved, in relation to the integration of pig production and the dramatic increase in research efforts in pig nutrition and production. Through integration, large producers can consolidate resources and maximize profits and efficiency. The increased research interest and efforts in pig production have given scientists and producers the opportunity to collaborate to adapt to challenges and identify possible solutions to issues brought on by a volatile global market. Intestinal health (23%), general nutrition and growth (23%), and amino acid nutrition (15%) were the top 3 areas (61%) leading research trends in pig nutrition and production. Major dietary interventions with feed additives evaluated include functional amino acids, feed enzymes, pre-/pro-/post-biotics, and phytobiotics with a common goal to improve the growth efficiency by enhancing nutrient utilization and intestinal health. With increasing global issues with environment, pig producers and the supporting scientists should continue their efforts to improve the production efficiency and to reduce the environmental footprint from pig production.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.295-301
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• 2015

A theoretical analysis was carried out to examine the concentration behavior of methane from a biogas using a polysulfone membrane. After the governing equations were derived for the cocurrent flow mode in a membrane module, the coupled nonlinear differential equations were numerically solved with the Compaq Visual Fortran 6.6 software. At the typical operating condition of mole fraction of 0.7 in a feed stream, the mole fraction of methane in the retentate increased to 0.76 while the normalized retentate flow rate to the feed flow rate decreased from 1 to 0.79. When either the mole fraction of methane in a feed increased or the pressure of the feed stream increased, the methane mole fraction in the retentate increased. On the other hand, it was found that as either the membrane area decreased or the ratio of the permeate pressure to the feed pressure increased, the methane mole fraction in the retentate decreased. In case that the stage cut increased, the methane mole fraction in the retentate increased while the recovery of methane slightly decreased.

• Membrane and Water Treatment
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• v.1 no.1
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• pp.1-12
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• 2010

Membrane distillation process was used for purification of pre-treated natural water (tap water). The rejection of inorganic and organic compounds in this process was investigated. The obtained rejection of inorganic solutes was closed to 100%, but the volatile organic compounds (VOCs) diffused through the membrane together with water vapour. The content of trihalomethanes (THMs) in the obtained distillate was two-three fold higher than that in the feed, therefore, the rejection of the total organic compounds present in the tap water was reduced to a level of 98%. The intensive membranes scaling was observed during the water separation. The morphology and composition of the fouling layer was studied using scanning electron microscopy coupled with energy dispersion spectrometry. The influence of thermal water pre-treatment performed in a heat exchanger followed by filtration on the MD process effectiveness was evaluated. This procedure caused that significantly smaller amounts of $CaCO_3$ crystallites were deposited on the membrane surface, and a high permeate flux was maintained over a period of 160 h.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.56-61
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• 1996

In this paper, new buck converter of a TV power system is presented. First, we devised a revised driving circuit for an emitter-coupled type buck converter, by which it is possible to reduce the material cost of transformers and voltage stress of power device. Secondly, we adopted a hybrid oscillation technique. When TV system is in off-stage, initial standby power which is necessary for remote controllable TV system is supplied by self-oscillating mode. Main power which is necessry in TV system bing on state is provided by an externally triggered oscillating mode. The switching frequency is synchronized to the oscillating frequency of horizontal deflection in TV, by which we can reduce picture noises and the size of power transformer. Thirdly, a simple error amplifier is inserted to the feed-back loop to keep the output voltage constant which means pulse width modulatio mode is added in driving part of power device. Finally, we showed by experiments that our proposed converter performs well enough to be close to the theoretically predicted values.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.255-258
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• 2005

In this paper, we verify that the bandwidth of the optimized disk-loaded monopole antenna with electromagnetically coupled feed obtained using a genetic algorithm is broader than the theoretical bandwidth limit of 2/Q by simulation as well as by measurement. The measured bandwidth of the optimized antenna (kr : 0.599) is about 42% from 380 MHz to 580 MHz (VSWR<5.8). The efficiency measurement of the antenna is over 90% for the frequency band of operation.