• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.7-10
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• 2007

최근 이동통신을 이용해 다양한 서비스를 제공하기 위하여 멀티 밴드, 멀티 채널의 송수신기를 단일칩화 하기 위한 연구가 활발히 진행되고 있다. CMOS 집적 회로 기술은 가격 경쟁력이 높고 집적도가 높아 멀티 밴드, 멀티 채널 송수신기를 집적화하기에 적합하다. 그러나 0.18 ${\mu}m$ 이하의 채널 길이를 갖는 CMOS 집적 회로는 1.8 V 이하의 낮은 공급 전압을 제공함으로 높은 이득을 갖는 mixer의 구현이 어렵고, mixer에서 발생되는 2, 3차 상호 변조에 의한 왜곡으로 선형성이 문제가 된다. 이런 문제점을 해결하기 위해서 기능성 능동부하를 적용하여 선형성을 향상한 Direct Conversion Down Mixer를 설계 분석 하였다.

• Journal of electromagnetic engineering and science
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• v.2 no.1
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• pp.56-58
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• 2002

In this paper, the double conversion gate mixer using a half-LO frequency is described at 25 GHz band. The proposed mixer uses two HEMTs excited by a single LO signal of half-LO frequency in order to generate the second IF signal. That is, the LO signal having the half-LO frequency is only fed into the gate of the first HEMT mixer as a normal gate mixer. The LO signal through the first mixer is find into the second mixer The proposed miler requires not only half of the normal LO frequency, but also lower LO power than the conventional subharmonically pumped milers. Over the bandwidth of 500 MHz at 24.5 GHz, the conversion gain is 2.5 dB, the noise figure is 9 dB, and the isolation between RF and LO port is 32 dB when the LO poller is 0 dBm at 12.65 GHz.

• Korean Journal of Veterinary Service
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• v.24 no.4
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• pp.379-382
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• 2001

To confirm the effect of food and water deprivation prior to Newcastle disease(ND) virus vaccination, three hundred chicks were divided into five groups with three replications. ND vaccine were sprayed to at 1 -day old chicks at commercial hatchery. Secondary and third vaccination was conducted at 2-week old and 24-day old chicks by LaSota strain. Control was conventionally vaccinated without withdrawing the food and water before or after vaccination. In group 2(G2) and 3(G3), LaSota strain was vaccinated to chicks before and after fasting the food and water for 3 and 2 hours, respectively. Group 4(G4) has the same fasting time of group 2, but supplemented the skim milk in vaccin dilution water. In group 5(G5), skim milk was added into group 3. Weight gain, feed intake and feed conversion were weekly measured for 5 weeks. Blood was collected from wing vein at 24 and 35 days of age. Each serum antibody level were measured by hemagglutination inhibition(HI) test. The average weight gain, feed intake, feed conversion of all group were not significantly different. Weight gain of each groups was 1910.30(control), 1875.28(G2), 1952.12(G4) and 1896.05(G5), respectively. Feed intake of all group was recorded at 3160.67(control), 3167.07(G2), 3189.48(G3), 3157.85(G4) and 3178.16(G5), respectively. The feed conversion of each groups was 1.655(control), 1.688(G2), 1.633(G3), 1.699(G4) and 1.676(G5), respectively. The HI titer of G4 was $ 5.50{\Pm}$1.40 and significantly higher than the other groups (p<0.05)(control : $4.36{\Pm}$1.87 , G2 : $5.18{\Pm}$2.14, G3 : $4.51{\Pm}$2.19, G : $5.28{\Pm}$1.58 at 35 days old. The results of this experiment indicated that two or three hours of fasting time before or after vaccination would be able to show the higher antibody level against ND virus.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.9
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• pp.743-749
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• 2002

A 1.5V 70㏈ 100MHz CMOS class-AB complementary operational amplifier is presented. For obtaining the high gain and the high unity gain frequency, the input stage of the amplifier is designed with rail-to-rail complementary differential pairs which are symmetrically parallel-connected with the NMOS and the PMOS differential input pairs, and the output stage is designed to the rail-to-rail class-AB output stage including the elementary shunt stage technique. With this design technique for output stage, the load dependence of the overall open loop gain is improved and the push-pull class-AB current control can be implemented in a simple way. The designed operational amplifier operates perfectly on the complementary mode with 180$^{\circ}$ phase conversion for 1.5V supply voltage, and shows the push-pull class-AB operation. In addition, the amplifier shows the DC open loop gain of 70.4 ㏈ and the unity gain frequency of 102 MHz for $C_{L=10㎊∥}$ $R_{L=1㏁}$ Parallel loads. When the resistive load $R_{L}$ is varied from 1 ㏁ to 1 ㏀, the DC open loop gain of the amplifier decreases by only 2.2 ㏈.a$, the DC open loop gain of the amplifier decreases by only 2.2 dB.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.10
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• pp.1394-1399
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• 2001

Influence of pre-weaning nutrition on post-weaning gain was assesses under intensive feeding in Malpura lambs. Thirty six Malpura (15 days old) lambs divided in to 3 equal groups were maintained on high (G1), medium (G2) and low (G3) energy and protein containing creep mixture with free suckling and ad libitum roughage (pala leaves: Ziziphus nummularia) up to 90 days of age. The lambs during post-weaning phase were fed on a 40:60 roughage and concentrate based composite diet to assess their post-weaning growth response. Total dry matter intake in pre-weaning phase was higher (p<0.01) in G3 than G2 and G1 while feed conversion efficiency was better in G1 than G2 and G3. The birth weight, 15 days body weight and weaning weight were however similar in the three groups. The finishing body weight, total body weight gain and average daily gain during post-weaning phase were higher (p<0.01) in G3 than in G1 and G2. The lambs in G3 consumed more (p<0.01) dry matter during post-weaning phase along with better feed conversion efficiency than other two groups. However, the DCP intake/kg body weight gain was higher in G1 than G2 and G3. Digestibility of DM, OM, CP, NDF, ADF and energy were similar among the three groups during post-weaning phase. Percent nitrogen retention as nitrogen intake was higher (p<0.01) in G3 (71.1%) than G1 (67.7%) and G2 (69.7%) during the post-weaning phase of study. The G1, G2 and G3 lambs in post-weaning phase consumed 8.1, 7.7 and 8.1 g DCP and 246.8, 227.2 and 246.1 kcal $DE/kg\;W^{0.75}/d$ and had 84.4, 80.0 and 111.1 g average daily gain, respectively. It is concluded that the lambs fed on low energy and protein containing creep mixture in pre-weaning phase showed improvement in growth during post-weaning phase under optimum feeding regime.

• Journal of Power Electronics
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• v.17 no.4
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• pp.849-859
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• 2017

This paper illustrates the analysis and design of a multi-resonant converter applied to an electric vehicle (EV) charger. Thanks to the notch resonant characteristic, the multi-resonant converter achieve soft switching and operate with a narrowed switching frequency range even with a wide output voltage range. These advantages make it suitable for battery charging applications. With two more resonant elements, the design of the chosen converter is more complex than the conventional LLC resonant converter. However, there is not a distinct design outline for the multi-resonant converters in existing articles. According to the analysis in this paper, the normalized notch frequency $f_{r2n}$ and the second series resonant frequency $f_{r3n}$ are more sensitive to the notch capacitor ratio q than the notch inductor ratio k. Then resonant capacitors should be well-designed before the other resonant elements. The peak gain of the converter depends mainly on the magnetizing inductor ratio $L_n$ and the normalized load Q. And it requires a smaller $L_n$ and Q to provide a sufficient voltage gain $M_{max}$ at ($V_{o\_max}$, $P_{o\_max}$). However, the primary current increases with $(L_nQ)^{-1}$, and results in a low efficiency. Then a detailed design procedure for the multi-resonant converter has been provided. A 3.3kW prototype with an output voltage range of 50V to 500V dc and a peak efficiency of 97.3 % is built to verify the design and effectiveness of the converter.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.657-662
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• 2014

We demonstrate a simulation of a parallel hybrid fiber amplifier in the C+L-band with a gain controlling technique. A variable optical coupler is used to control the input signal power for both EDFA and RFA branches. The gain spectra of the C+L-band are flattened by optimizing the coupling ratio of the input signal power. In order to enhance the pump conversion efficiency, the EDFA branch was pumped by the residual Raman pump power. A gain bandwidth of 60 nm from 1530 nm to 1590 nm is obtained with large input signal power less than -5 dBm. The gain variation is about 1.06 dB at a small input signal power of -30 dBm, and it is reduced to 0.77 dB at the large input signal power of -5 dBm. The experimental results show close agreement with the simulation results.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.1
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• pp.91-97
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• 1993

This experiment was carried out to examine the effects of urea-treated rice straw feeding on the growth performance of crossbred Holstein heifers under different feeding conditions. In the first experiment, the animals were given diets having 2 levels of TDN and CP and 3 levels of crude fiber (22, 30 and 36%) which were formulated with urea-treated rice straw and concentrates. Daily weight gain of heifers was not different between 22% and 30% CF diets, but the reduction of TDN or CP level to 90% of the requirements decreased the weight gain. Fiber content of 36% also reduced the body weight gain. The reduction of TDN significantly reduced DM intake and increased feed conversion ratio. Feed cost per kg weight gain was significantly increased by an increase in CF to 36%. In the second experiment, separate feeding and total mixing feeding were compared. There were no significant differences between the two feeding systems in body weight gain although the possibility of superiority in SF to TMF remained. DM intake was not affected by the feeding system, but 30% CF diet gave higher DM intake. Feed cost per kg weight gain was lower in the 30% CF diet.

• Korean Journal of Poultry Science
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• v.28 no.1
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• pp.55-59
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• 2001

The objective of these experiments gas to investigate the feeding of Powerfeel supplementation on performance and intestinal microflora of broiler chicks. Five treatments were allocated into 0, 0.025, 0.050, 0.075, 0.10% Powerfeel with four replications for five weeks. Diets contained 21.5% CP, 3,100 kcal/kg ME for the first three weeks and 19% CP, 3,100 kcal/kg ME for the rest two weeks. Weight gain, feed intake, feed conversion were weekly measured. E. coli and Salmonella were examined from cecum and ileum at the end of experiment. ND titer were also measured at five weeks old after first and booster vaccination at 14 and 21 days of age. In experiment 1, Weight gain of Powerfeef treatments was significantly higher for five weeks (P〈0.05). Feed intake increased on all Powerfeel treatments. Chicks fed Powerfeel improved feed conversion ratio(FCR) significantly compared to that of control (P〈0.05), but was not shown the consistency. In experiment 2, Weight gain and feed consumption of chicks fed Powerfeel were tended to increase, but were not statistically different from control. Powerfeel treatments showed significantly lower FCR than control(P〈0.05). The number of Salmonella and E. coli of chicks ileum fed Powerfeel were highly decreased, compared to those of control in both experiments. Powerfeel supplementation seemed to decrease the number of both Salmonella and E. coli in illeum, but was not consistency in cecum. Chicks fed Powerfeel showed significantly higher ND titer than control (P〈0.05). These results indicated that the optimum level of Powerfeel to maximize the performance of broiler chicks were estimated from 0.050 to 0.075% in broiler diets.

• Korean Journal of Organic Agriculture
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• v.29 no.1
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• pp.125-136
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• 2021

In this study, a meta-analysis was performed to determine the correlation between the expression of tight junction protein in the intestine and the productivity of broiler chickens. A total of 9 papers were selected in which the result values consisted of the mean and standard deviation value, and the standardized mean difference was calculated to compare the mean of the control and treatment groups. A meta-regression test was conducted to determine the effect of each type of tight junction protein. The TJPs observed in each study were claudin1, claudin2, claudin3, occludin, ZO1, ZO2, etc., and the indicators to indicate the productivity of broilers were body weight gain (BWG), feed intake (FI), and feed conversion rate (FCR), average daily feed intake (ADFI), average daily gain (ADG), and feed/gain ratio (FPG). Although there are differences depending on the type of TJP, it was found that the change in expression level had a close effect on the productivity of broilers. In particular, occludin significantly correlated with body weight gain, feed intake, and feed conversion rate. Based on the results of this study, a study on a method to effectively increase the expression level of TJP is expected to contribute to improving the productivity of broilers and producing safe livestock products.