• Proceedings of the KIEE Conference
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.2052-2054
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• 2004

The TX/RX broadband L-type circular polarization antenna using LTCC at K/Ka band has been presented. This antenna has been analyzed in compensation for LTCC with relative permittivity 5.2 and could have been integrated with RF component. As the measured 10dB impedance circular polarization bandwidth of the proposed antenna is 7%(20.8GHz${\sim}$22.2GHz) at the K band and 2.3%(30.9GHz to 31.6GHz) at the Ka band. Also the gain of the antenna is -0.7${\sim}$3.05dBi at the K band and -2.8${\sim}$1dBi at the Ka band. The purpose of the research is to design an efficient antenna structure for satellite communication at K/Ka band. the antenna should be used for both TX and RX frequency bands. The antenna will be mounted on LTCC(Low Temperature Co-fired Ceramic) so that it can be integrated with other RF circuits. This research is important because of the following reasons. 1) The frequency ranges of satellite communication tends to move up to higher frequency such as Ka band or milimeter wave band. 2) Design of antenna for smaller size, lighter weight and less loss is preferred by most RF engineers. 3) Antennas on LTCC enables to integrate the antenna with other RF circuits, and thus, one can reduce the size and loss of the RF system.

• Korean Journal of Animal Reproduction
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• 제22권4호
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• pp.341-347
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• 1998

This study was conducted to determine changes in circulating progesterone and Insulin-like Growth Factor-1(IGF-1) concentrations according to daily gain of 0.5 and 0.7 kg ; from 33 weeks of age until the onset of regular oestrus cycles in the heifer of Hanwoo. In all animals, progesterone concentrations was undetectable until just before first oestrus. A small progesterone elevation of approximately 6 days duration(based upon the mean progesterone profile) preceded the first oestrus in 13 heifers. The mean age at first oestrus of the daily gain 0.7 kg(331.0$\pm$ 15.0 days) group was earlier than those of the daily gain 0.5 kg(358.9$\pm$7.9 days) group, and the mean weight at first oestrus of the daily gain 0.7 kg(236.0$\pm$4.7 kg) group was heavier than those of the daily gain 0.5 kg(224.8$\pm$9.7 kg) group. IGF-1 concentrations from day 3 to 15 of first oestrus were higher than those of the earlier luteal stage(Day 0~1) and the luteal regression stage (Day 18~20). IGF-1 concentrations according to the growth stage (from 33 weeks to 57 weeks) increased gradually. On the basis of these results, we suggest that the onset of first oestrus in Hanwoo heifer is about 345 day of age, and progesterone concentrations are closely related to the IGF-1 concentration.

• Journal of Nutrition and Health
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• 제18권2호
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• pp.115-125
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• 1985

This study was undertaken to make comparative study on the effect of kinds(Cellulose, Agar) & contents(2.5%, 5%, 10%) of the dietary fiber with the normal Fe intakes(66ppm) on the Fe metabolism in rats during the four weeks of growth period Sixty-four male rats of wistar strain weighing $76.2\pm2.5g$ were randomly designed to one of the 8 groups. All the groups received basal diet with 9% casein and no acorbic acid. The results obtained are summarized following; 1) Feed consumption per 100g b.w. & body weight gain in normal Fe intake groups tended to be higher than Fe deficient groups, but, there was no significant difference among the 8 groups. However, body weight gain & feed consumption in cellulose sloops were significantly higher than agar groups in all the levels tested.(P<0.01). 2) Fecal Fe excretion per 100g b.w. increased significantly with increase in dietary fiber during the four weeks, but there was no significant increase in fecal weight per l00g b.w. & urinary Fe excretion. 3) Hemoglobin concentration & hematocrit decreased slightly in SFe-10% up with SFe - C group after fourth weeks, but, the difference was not significant. 4) In cellulose groups, serum-Fe remakendly decreased & TIBC increased with increase in the levels of cellulose during the fourth weeks. In agar groups, serum-Fe & TIBC tended to decrease with increased dietary fiber intake. Therefore, at high intakes of both fibers, the levels of transferrin saturation were similar to that of DFe group. 5) Contents of Fe in liver, kidney & spleen increased significantly only in 10% agar diet. The remaining 7 groups did not differ significantly. It may imply agar affect in Fe utilization from storage in rats. In conclusion, inhibitory effect of dietary fiber on Fe absorption depended upon the kinds & level of consumption Results from the present study shoves the effects of purified dietary fiber on Fe absorption in gastrointestinal tract and it may be different from those of dietary fibers consumed as a part of complex diet.

• Asian-Australasian Journal of Animal Sciences
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• 제10권4호
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• pp.435-438
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• 1997

Twelve newborn goat kids born of philippine does (3.5 and 5 years old) were used in this study. Four mother (candidate) doe goats were randomly allocated to each group. The mother does were infected orally with three levels (0, 15,000 and 30,000 larvae) of infective Haemonchus contortus larvae. Before infection all animals were housed in individual pens with concrete floors. They were provided with a uniform management. Estrus of does were synchronized using PGF2 alpha. All the animals were bred naturally by the same buck. Baby goat born of infected mother goats were divided into three groups. $T_1$, $T_2$ and $T_3$), respectively, from mother treatment groups. Birth weight and growth of goat kids born from H. contortus infected mother goats were determined. Birth weights of kids of $T_1$, $T_2$ and $T_3$ were 1.9, 1.5 and 1.2 kg, respectively. No significant (p > 0.05) differences in birth weight of kids for the 3 treatment groups were found. However, significant (p < 0.05) effects of stomach worm infection and duration of infection on liveweight gain of kids were observed. After second and third week of birth, respectively, the kids of groups 3 and 2 registered lover liveweight gains than the kids in control group. However, no significant (p > 0.05) difference in liveweight gain was found between the kids of infected mother does. Fecal egg counts of the infected mother does showed patent infections which also indicated by postmortem worm counts. However, no worm egg was found in the feces of the test kids.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제41권2호
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• pp.74-77
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• 2015

Objectives: Transpositioning of the inferior alveolar nerve to prevent injury in lower jaw has been advocated for orthognathic, pre-prosthetic and for implant placement procedures. However, the concept of infra-orbital nerve repositioning in cases of mid-face fractures remains unexplored. The infraorbital nerve may be involved in trauma to the zygomatic complex which often results in sensory disturbance of the area innervated by it. Ten patients with infraorbital nerve entrapment were treated in similar way at our maxillofacial surgery centre. Materials and Methods: In this article we are reporting three cases of zygomatico-maxillary complex fracture in which intra-operative repositioning of infra-orbital nerve into the orbital floor was done. This was done to release the nerve from fractured segments and to reduce the postoperative neural complications, to gain better access to fracture site and ease in plate fixation. This procedure also decompresses the nerve which releases it off the soft tissue entrapment caused due to trauma and the organized clot at the fractured site. Results: There was no evidence of sensory disturbance during their three month follow-up in any of the patient. Conclusion: Infraorbital nerve transposition is very effective in preventing paresthesia in patients which fracture line involving the infraorbital nerve.

• The Journal of the Korea institute of electronic communication sciences
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• 제13권1호
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• pp.15-22
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• 2018

In this paper, a microstrip-fed triple-band monopole antenna for WLAN/WiMAX applications was proposed. The proposed antenna is consist of two arc-shaped and one strip line structure, then get the three current path and then designed in order to get triple resonant characteristics. We carried out simulation about parameters. Taking account of coupling effect, Adjusted the length of the two arc-shaped and one strip line, we get the optimized parameters. The proposed antenna is fabricated on an FR-4 substrate, the dielectric constant is 4.4, and total size is $23.5mm(W1){\times}32.0mm(L1){\times}1.0mm(t)$, and its proposed antenna size is $21.0mm(W6){\times}31.0mm(L7)$. From the measured results, return loss of the proposed antenna satisfied return loss 927 MHz (1.844~2.771 GHz), 926 MHz (3.33~4.256 GHz), and 1,415 MHz (5.13~6.545 GHz). And measured results of gain and radiation patterns displayed for operating bands.

• Journal of Welding and Joining
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• 제18권2호
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• pp.49-56
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• 2000

Recently developed Austenite stainless steel, 309L was used to overlay on 3Cr-1Mo-V-Ti-B steels, using Electroslag welding process, which wide electrodes were adopted. Transition region in welding interlayer relating to disbonding crack was investigated. Also, the effect of welding condition on the width of transition region and coarsening grains of the austenite were studied. 1) With increasing welding speed the width of martensite at transient region was increased, but the amount of delta ferrite in weld metal was reduced, being fine grained. 2) The form of martensite at the transition region was occurred by reversible transformation during cooling since the interdiffusion of Cr and Ni from weld metal and Fe and C from base metals at the transition region, causes to lowering the concentration of Cr and Ni at the transition region, leading to increasing Ms point. 3) With increasing welding speed, the grain of austenite formed at the welding interface was finer. With increasing welding current under the same welding speed, the grain size of the austenite was finer. At high current, original grain size of the austenite is coarse, but the austenite has fine grains because the austenite was transformed to martensite during cooling. 4) In the case of high welding speed, the width of martensite at the welding interface was increased, but the grain size of austenite at the welding interface was finer. This indicates that the inhibition of disbonding crack may be achieved through dispersening fine carbides in the gain boundary.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제47권2호
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• pp.114-121
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• 2019

Tailless aircraft have advantages of low visibility compared to conventional aircraft, but drawback of poor stability as well which makes designing controller difficult. The controller design is more difficult, especially when the center of gravity moves due to store release or fuel consumption during flight. In this paper, an L1 adaptive controller is proposed as a way to overcome these problems. The reliability and performance of the controllers were verified by non-linear simulations. RPV Flying Quality Design criteria were used for design criteria. Using the simulation, it is shown that the adaptive controller maintains stability of the unmanned aircraft for sudden large change in the inertial properties. It is also shown that the calculation burden can be reduced when it is used with the gain scheduling method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제29권11호
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• pp.857-867
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• 2018

Active array radar is evolving into digital active array radar. Digital active array radar has many advantages for making several simultaneous radar beams from the digital receive data of each element. A digital-type transceiver(TR) module is suitable for this goal in radar. In this work, the design results of an L-band digital TR module are presented to verify the possibility of fabrication for a digital active array antenna. This L-band digital TR module consists of a gallium-nitride-type HPA to achieve a more than 350-W peak output power and one-chip transceivers that include a digital waveform generator and analog digital converter. The receiving gain was 47 dB, the noise figure was less than 2 dB, and the final output type of the four channel receiving paths was one optic signal.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제21권4호
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• pp.679-687
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• 2017

In this paper, a microstrip-fed triple-band monopole antenna with DGS (Defected Ground Structure) for WLAN/WiMAX applications was proposed. The proposed antenna is based on a microstrip-fed structure, and composed of two strip lines and DGS structure and then designed in order to get triple band characteristics. We carried out simulation about parameters. Adjusted the position and length of the two strips and three slits, we get the optimized parameters. The proposed antenna is fabricated on an FR-4 substrate of which the dielectric constant is 4.4, and its overall size is $34mm(W_1){\times}34mm(L_1){\times}1.6mm(t)$, and its proposed antenna size is $17.0mm(W_6){\times}30.75mm(L_3+L_4+L_9)$. From the fabricated and measured results, return loss of the proposed antenna satisfied return loss -10dB bandwidth 360 MHz (2.335~2.695 GHz), 645 MHz (3.37~4.015 GHz) and 1,770 MHz (5.14~6.91 GHz). And measured results of gain and radiation patterns characteristics displayed for operating bands.