• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.3
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• pp.174-180
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• 2001

Dusky spinefoot, Siganus fuscescens live primarily in shore reefs with sea weeds, like around Jeju Island in Korean south sea. Therefore they are caught much by set net in the coast of Jeju Island. We carried out measurements of the dorsal aspect target strengths of Dusky spinefoot in order to study the influences of swim bladder for fishes. and have obtained some desired results though not sufficiently complete as comparison with target strengths of fishes before and after the air gas in the swim bladder of fish is taken off by an injector. The appropriate equations share the common form TS = A + 20 log L. TS = B + 20/3 log W where TS is the average dorsal aspect target strength in decibels. L is the fish total length in centimeters. W is the fish total weight in grams, and the coefficient A and B are determined by a least mean squares regression analysis. The results obtained before the air gas in the swim bladder of fish is taken off are TS = -63.16 + 20 log L TS = -50.50 + 20/3 low W and, the results obtained after the air gas in the swim bladder of fish is taken off are TS = -65.29 + 20 log L TS = -52.62 + 20/3 log W As above result, the differences of target strengths before and after the air gas is taken off from swim bladder are 2.12-2.13 dB, but the maximum difference of target strengths of both cases averaged according to the fish aspects from $-45^\circ$ to $45^\circ$ is 5.87 dB, and the average difference of them is 2.01 dB.

• Journal of Pharmaceutical Investigation
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• v.32 no.1
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• pp.13-19
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• 2002

Water-lipid soluble multivitamin formulations were widely used to reduce the disease and stress of animals as husbandry has made a remarkable progress in recent. But the efficiency of these formulations is far from satisfactory. So, this study was attempted to develop the physically and chemically stable and useful multivitamin o/w emulsion. Multivitamin o/w emulsion composed of water, soybean oil (10%, v/v), vitamin A, D, E, K, $B_2,\;B_6,\;B_{12}$ and panthenol. To make a stable o/w emulsion, the egg lecithin (2%, w/v) and glycerin (2.5%, w/v) were used for emulsifier and thickening agent, respectively. The oil in water emulsion system was manufactured by microfluidizer and the physicochemical stability of this emulsion was evaluated. The average particle size and interfacial tension were measured. From the result of interfacial tension tested, critical micelle concentration of the egg lecithin was 0.5% (w/v) and optimal concentration for the preparation of emulsion was 2% (w/v). The mean particle size was about $0.6\;{\mu}m$ which was suitable for injections. Short-term accelerated stability as physical stability study was tested by centrifuging and freeze-thawing the emulsion samples. The additions of vitamins resulted in the increment of particle size and reduction of physical stability of emulsion. But it is not an enormous problem for the stability of emulsion. Also, we have performed the long-period preservation stability test for the vitamins. All vitamins were analysed by HPLC. The result of storage under $4^{\circ}C$ and dark conditions demonstrated that all vitamins were maintained stable at least 16 weeks, except for vitamin $B_{12}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.992-999
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• 2008

This paper describes the design of SPST PIN diode switch which has a 2 kW high power handling capability within $50{\mu}s$ switching speed in $20{\sim}100$ MHz VHF-band. Design factors were investigated and it was confirmed by simulation that the characteristics of insertion loss, VSWR, and isolation met design goal. Also, the capability to handle 2 kW high power with maximum fast switching speed less than $20{\mu}s$ was confirmed and insertion loss less than 0.2 dB, VSWR less than 1.17:1, and isolation higher than 40 dB were obtained by experiments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.900-905
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• 2009

A common drain feedback CMOS wideband LNA with current bleeding and input inductive series-peaking techniques is presented in this paper. DC coupling is adopted between cascode and feedback amplifiers, so that the gain and NF of the LNA can be dynamically controlled by adjusting the bleeding current. The fabricated LNA shows the bandwidth of 2.5 GHz. The high gain mode shows 17.5 dB gain with $1.7{\sim}2.8\;dB$ NF and consumes 27 mW power and the low gain mode has 14 dB gain with $2.7{\sim}4.0\;dB$ NF and dissipates 1.8 mW from 1.8 V supply.

• Food Science and Preservation
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• v.18 no.2
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• pp.171-177
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• 2011

In order to demonstrate the usefulness of Deodeok. the functions of Deodeok and the qualities of Cheongkukjang were investigated. DPPH (1.1-diphenyl-2-picryl-hydrazyl) radical scavenging activity of Deodeok extracted with 70% ethanol was higher than that of water extract. The direct antimutagenic effect of ethanol extract of Deodeok was examined by Ames test using Salmonella typimurium TA 98. The inhibition rates on ethanol extract at concentrations of 200, 1.000, 2.000, 3.000 and 4.000 ${\mu}g$/plate were 5.75, 31.38, 34.75, 53.50 and 83.75%, respectively. The inhibition rates of ethanol extract was higher over 2 times than that of water extract. The qualities including physicochemical and sensory properties of Deodeok Cheongkukjang were investigated over the following range of Deodeok levels; 5, 10, 15 and 20% (w/w). The strain used in Cheongkukjang manufacture was Bacillus sp. B-3 with the highest enzyme activities such as amylase and protease. During fermentation at $40^{\circ}C$ for 6 days. amino-type nitrogen content of Cheongkukjang containing 10% (w/w) Deodeok was more than others. When Deodeok content exceeded 15% (w/w), higher contents resulted in lesser amino-type nitrogen production. The results showed that Deodeok had influenced the growth of Bacillus sp. B-3. The L-value of Deodeok Cheongkukjang was decreased according to increasing the Deodeok contents. Sensory evaluation showed that Deodeok Cheongkukjang containing 10% (w/w) Deodeok was superior to other tested.

• Kyungpook Mathematical Journal
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• v.59 no.3
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• pp.377-389
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• 2019

We evaluate the convolution sum $W_{a,b}(n):=\sum_{al+bm=n}{\sigma}(l){\sigma}(m)$ for (a, b) = (1, 28),(4, 7),(2, 7) for all positive integers n. We use a modular form approach. We also re-evaluate the known sums $W_{1,14}(n)$ and $W_{1,7}(n)$ with our method. We then use these evaluations to determine the number of representations of n by the octonary quadratic form $x^2_1+x^2_2+x^2_3+x^2_4+7(x^2_5+x^2_6+x^2_7+x^2_8)$. Finally we express the modular forms ${\Delta}_{4,7}(z)$, ${\Delta}_{4,14,1}(z)$ and ${\Delta}_{4,14,2}(z)$ (given in [10, 14]) as linear combinations of eta quotients.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.29-34
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• 2021

For the purpose of Application to the small radar sensor, the MMIC Chips, which are the core component of the W-band, was designed in Korea according to the characteristics of the transceiver and manufactured by 60nm GaN and 0.1㎛ GaAs pHEMT process. The output power of PA is 28 dBm at center frequency of W-band and Noise figure is 6.7 dB of switch and LNA MMIC. Output power and Noise figure of MMIC chips developed in domestic was applied to the transmitter and receiver module through W-band waveguide low loss transition structure design and impedance matching to verify the performance after the fabrication are 26.1~27.7 dBm and 7.85~10.57 dB including thermal testing, and which are close to the analysis result. As a result, these are judged that the PA and Switch and LNA MMICs can be applied to the small radar sensor.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.12 s.354
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• pp.65-73
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• 2006

This work presents a 14b 200KS/s $0.87mm^2$ 1.2mW 0.18um CMOS algorithmic A/D converter (ADC) for intelligent sensors control systems, battery-powered system applications simultaneously requiring high resolution, low power, and small area. The proposed algorithmic ADC not using a conventional sample-and-hold amplifier employs efficient switched-bias power-reduction techniques in analog circuits, a clock selective sampling-capacitor switching in the multiplying D/A converter, and ultra low-power on-chip current and voltage references to optimize sampling rate, resolution, power consumption, and chip area. The prototype ADC implemented in a 0.18um 1P6M CMOS process shows a measured DNL and INL of maximum 0.98LSB and 15.72LSB, respectively. The ADC demonstrates a maximum SNDR and SFDR of 54dB and 69dB, respectively, and a power consumption of 1.2mW at 200KS/s and 1.8V. The occupied active die area is $0.87mm^2$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.24 no.3
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• pp.21-26
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• 2024

Design and fabrication method of W-band 12-way radial power combiner is proposed in this paper. The proposed structure is used with TE₁₀ to TEM mode converter, which is realized using 2-step impedance transformer. The pin structure for mode converter is well bonded to the housing so that environment conditions such as vibration or shock are not affected. Proposed W-band power combiner has less than 0.7 dB insertion loss and more than 13 dB return loss from 88 GHz to 98 GHz. The measured output isolations between each other are greater than 7.5 dB from 82 to 100 GHz and phase differences are less than 10 degree from 88 to 96 GHz. Proposed power combiner is expected compact radar and various applications requiring for high power and stable environment conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.949-955
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• 2020

In this Study, Social Network Analysis of IoT related patents in South Korea, China, and Japan was conducted from the viewpoint of patent informatics. To this end, 2,526 patents filed by PCT until December 2019 were investigated up to the subclass level of the IPC code. As a result, in the case of South Korea, representative IPC codes are in the order of G06Q, H04L, G06F, H04W, and the highest frequency of interconnection is H04L→H04W, H04W→H04L, H04W→H04B. In China, the representative IPC codes are in the order of H04L, H04W, G05B, G06Q. South Korea has strong technological convergence centered on the G06Q, while China has strong convergence centered around H04L and H04W. Moreover, in China, H04L and H04W have more diverse combinations than in South Korea in Section A, B, G, and H. In the future, it is necessary to study the diversity of technology convergence of H04L and H04W in China.