• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.11
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• pp.1518-1523
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• 2018

A method for designing a DDQYA fed by a CPW is proposed in this paper. The proposed CPW-fed DDQYA consists of two series-connected strip dipoles, a ground reflector, and a strip-pair director. Instead of the conventional microstrip feed line in which the signal line is located on the substrate opposite to the antenna, a CPW is used because CPW is located on the same side with the antenna, and so the fabrication is easy. The strip-pair director is composed of two horizontally-separated strips, and it is added above the second dipole to enhance the gain in the high frequency region. A prototype of the proposed CPW-fed DDQYA is fabricated on an FR4 substrate. The fabricated antenna has a frequency band of 1.66-3.38 GHz(68.3%) for a voltage standing wave ratio < 2, and measured gain ranges 5.0-7.3 dBi over a frequency band of 1.60-2.90 GHz.

• Journal of Nutrition and Health
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• v.30 no.6
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• pp.639-647
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• 1997

The effect of excess L-ascorbic acid(AsA) in blood, liver lipid levels and peroxidation status were investigate . Ten Sprague-Dawley male rats weighing 150-200g were fed 300mg AsA/100g body weight/day, mixed into ground chow diet, for 4 weeks. And another set of then rats were fed only chow diet as the control. Average body weight gain was slightly lowered by AsA feeding without food intake change. The AsA group showed higher AsA levels in plasma and liver than the control group. In addition, the AsA group showed a higher plasma TBARS value. Liver TBARS seemed to be elevated in the AsA, but not significantly. The hemolysis of red cells tended to increase with excess AsA, accompanied by a raised GSH-Px activity and lowered total GSH levels. Plasma HDL-Chol level was increased while the levels of total Chol, LDL-plus VLDL-Chol , and triglyceride were unchanged . Atherogenic index decreased. Hepatic TG levels were also decreased, but the total amount of Chol increased slightly . Platelet TXA$_2$ production was inhibited by excess AsA feeding. Above results indicafe that oral feeding of excess AsA may be beneficial in reducing the risk of atherosclerosis ; however such practice may be detrimental for tissue lipid peroxidation and weight gain.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1022-1032
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• 1999

The radiation characteristics of a microstrip circularly-polarized aperture-patch $8\times8$ array antenna are investigated at X-band. The radiator consists of a truncated square aperture on the ground plane with an inclined rectangular patch inside, and it is coupled by a microstrip line on the opposite side of the ground. The element spacing of the array was chosen as $0.8\lambda_0$so as to minimize the mutual coupling and maximize the gain. A corporate feed network was employed to distribute the power to each element through four Wilkinson and two T-junction dividers. Measurement results for the $8\times8$ array at 10 GHz showed a directivity of 26.3 dBi, a gain of 22.2 dBi, an axial ratio of 2.97 dB, and a side lobe level of -12.7dB. It was observed that when the array size increases, the directivity increases while the efficiency decreases.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.376-380
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• 2014

In the present study, oblique L-shaped monopole slot antenna with broadband characteristic is newly proposed. For bandwidth enhancement as well as size reduction, L-shaped slot with two open-terminations on the ground edge is used. The lower part of L-shaped slot comprises oblique form for bandwidth enhancement in low frequency band, whereas its higher part comprise tapered form for its enhancement in high frequency band. The short-circuit terminated microstrip line which is generally known to be more useful for bandwidth enhancement than open-circuit termination is used. The measured impedance bandwidth($S_{11}{\leq}-10dB$) and gain of the fabricated antenna have been observed to be 4.72 GHz (2.28~7 GHz) and more than 3dBi over the passband respectively.

• English Language & Literature Teaching
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• v.17 no.3
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• pp.213-235
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• 2011

The aim of this study is to present preliminary results from an ongoing large-scale study of English-language future goal orientations held by Japanese university students. The work here involves an investigation of learners in multiple disciplines, from five universities, both public and private, in the Kanto-region of Japan, and their perspective on their future use of English. The results summarize written essays on L2-goal orientations. Preliminary results indicate Japanese learners (n = 629) as a whole have disparate L2-learning goals; however, these can be summarized into four broad categories: career, personal life, study, and general; and early findings indicate that most learners (63.56%) are oriented to career or personal goal orientations, while others are oriented to study and general. These early results help us to gain a better understanding of the future goals of Japanese university learners and their views of English usage in the future.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.340-343
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• 1999

In this paper, we propose a wide range PLL(Phase Locked Loop) for 64X CD-ROMs & l0X DVD-ROMs. The frequency locking range of the Proposed PLL is 75MHz~370MHz. To reduce jitters caused by large VCO gain and supply voltage noise, a new V-I converter and a differential delay cell are used in 3-stage ring VCO, respectively. The new V-I converter has a 0.6V ~ 2.5V wide input range. In addition, we propose a new charge pump which has perfect current matching characteristics for the sourcing/sinking current. This new charge pump improves the locking time and the locking range of the PLL. This Chip is implemented in 0.25${\mu}{\textrm}{m}$ CMOS process. It consumes 55㎽ in worst case with a single 2.5V power supply.

• Speech Sciences
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• v.13 no.3
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• pp.19-33
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• 2006

This study explores whether Russian, known to have a process of syllable-final devoicing, reveals differences in vowel duration as a function of the underlying voicing of the coda stop. This paper also examines whether non-native speakers of Russian and English learn typical L2 values in vowel duration. The results indicate that vowels in Russian have a slightly longer mean duration before a voiced stop than before a voiceless stop (a mean difference of 9.52 ms), but in most cases the differences did not exhibit statistical significance. In English the mean difference was 60.05 ms, and the differences were in most cases statistically significant. All native Russian speakers of English produced larger absolute differences in vowel duration for English than for Russian, and all native English speakers of Russian produced smaller absolute differences for Russian than for English. More experienced learners seemed to achieve more native-like values of vowel duration than less experienced learners did, suggesting that learning occurs gradually as the learners gain more experience with the L2.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5827-5831
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• 2011

In this paper, 5Ghz microstrip patch antenna for wireless LAN is designed, fabricated, and measured. To obtain wide bandwidth and high gain, antenna parameters such as patch size(W, L), the length of the slot(C), and the slot width(D) are simulated by HFSS(High Frequency Structure Simulator). From these parameters optimized, the microstrip patch antenna is fabricated using FR-4 substrate. The measured results of the antenna are as follows: The center frequency of 5.2 GHz, insertion loss of -41.17dB, bandwidth of 258MHz, and VWSR of 1.1.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.5
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• pp.692-698
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• 1986

To fabricate digital I\ulcorner devices which are compatible with analog devices in a chip, phosphorus is implanted in the buried layer of I\ulcorner part which has already been diffused with arsenic impurity. Experimental results show that the muminim propagation delay time of I\ulcorner ring oscillator is 16-18 ns when the upward current gain of I\ulcorner transistor is 6-10.

• Nutritional Sciences
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• v.7 no.2
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• pp.65-69
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• 2004

A study was carried out to determine the effect of a very low-carbohydrate diet on weight gain, body composition, and serum levels of cholesterol, triacylglycerol, glucose, ketone bodies and insulin. Twenty rats (mean initial weight, 212 g) were divided into two groups and each group was assigned a conventional high-carbohydrate diet (control) or a very low-carbohydrate diet containing 59.8% ground pork rind snack and fed the diet for four weeks. Average daily body weight gain was not different between the two groups during the first two weeks, but was significantly lower in rats fed the very low-carbohydrate diet than in those in the control group during third (p<0.05) and fourth weeks (p<0.01). Feedintake as well as energy intake was lower in rats fed the very low-carbohydrate diet than in those in the control group. The very low-carbohydrate diet reduced (p<0.01) serum triacylglycerol (34$\pm$83 vs 82$\pm$8 mg/l00 mL) and insulin (3.90$\pm$0.53 vs 7.60$\pm$0.61 $\mu$IU/mL) levels, while increasing (p<0.01) ketone body level (368$\pm$25 vs 236$\pm$24 $\mu$mol/L), compared with the control. Serum glucose and total cholesterol levels were not different (p>0.05) between the two dietary treatments. Proximate analysis of carcasses showed that the very low-carbohydrate diet decreased (p<0.01) body fat (26.1$\pm$1.04 vs 30.5$\pm$0.86%), while increasing (p<0.01) body protein (63.1$\pm$0.94 vs 59.4$\pm$0.70%) contents. Results indicate that short-term feeding of a very low-carbohydrate diet is beneficial for alleviating risk factors known to involve cardiovascular diseases or artherosclerosis. However, more studies with model animals as well as humans are recommended to examine the long-term health benefits of low-carbohydrate diets.