• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.9
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• pp.865-871
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• 2016

This work presents a radar signal interferer to be used for evaluating the mutual interference among automotive radars. The developed interfering signal generator is composed of a reference signal generator and a 77 GHz transmitter. Reference signal generator is made up of commercial chips and board, it can generate various modulated signal such as triangular wave, sawtooth wave and random frequency hopping. The transmitter generates 77 GHz band signal by multiplying modulated reference signal frequency 28 times. Transmitter was fabricated using 65 nm CMOS process, it can operate horn antenna by built in on-chip waveguide feeder. The transmitter exhibited 7.31~8.06 dBm output power over a frequency lock range of 75.6~77 GHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.520-524
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• 1999

The Impact ionization rate is highly anisotropic at low electron energy, while it becomes isotropic at higher energy range in which impact ionization events frequently accur. In this study, full energy band structure obtained by pseudopotential method and Fermi's golden rule is used to calculate impact ionization rate. The calculated impact ionization rate is well fitted to a modified Keldysh formular at 300K and 77K. Full band Monte Carlo simulator is made to investigate the validity of the GaAs impact ionization coefficients at 300K and 77K. Impart ionization process is isotropic under the condition of steady state since anisotrophy appears during very short time at look. Impart ionization coefficients is nearly constant and is anisotropic in electric field applied along the <110> direction at 77K.

• Animal cells and systems
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• v.16 no.2
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• pp.87-94
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• 2012

Nur77 is a member of the nuclear receptor 4A (NR4A) subgroup, which has been implicated in energy metabolism. Although Nur77 is found in adipose tissue, where TR4 plays a key role in lipid homeostasis, the role of Nur77 in adipogenesis is still controversial. Although the Nur77 responsive element (AAAGGTCA) is partially overlapped with TR4-binding sites (AGGTCA $n$ AGGTCA: $n$=0-6), the regulatory role of Nur77 in TR4 function associated with adipocyte biology remains unclear. Here, we found that Nur77 inhibits adipogenesis and TR4 transcriptional activity. Treatment with a Nur77 agonist, 1,1-bis(3'-indolyl)-1-($p$-anisyl)-methane, during 3T3-L1 adipocyte differentiation reduced adipogenesis. In reporter gene analysis, Nur77 specifically suppressed TR4 transcription activity but had little effect on $PPAR{\gamma}$ transcription activity. Consistently, Nur77 also suppressed TR4-induced promoter activity of the TR4 target gene PEPCK, which is known to be important for glyceroneogenesis in adipose tissue. Furthermore, Nur77 suppressed TR4 binding to TR4 response elements without direct interaction with TR4, suggesting that Nur77 may inhibit TR4 transcription activity via binding competition for TR4-binding sites. Furthermore, DIM-C-$pPhOCH_3$ substantially suppressed TR4-induced PEPCK expression in 3T3-L1 adipocytes. Together, our data demonstrate that Nur77 plays an inhibitory role in TR4-induced PEPCK expression in 3T3-L1 adipocytes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.11
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• pp.1297-1306
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• 2012

This work presents a 77 GHz radar transmitter for the automotive radar system. An integrated 13 GHz frequency synthesizer fabricated using 130 nm RF CMOS process drives a commercial W-band compound semiconductor monolithic multifunction amplifier(MPA), which includes a frequency multiplier by six to generate 77 GHz transmitting signal. The 13 GHz frequency synthesizer includes a high efficiency injection buffer of 4 dBm output power to drive the MPA. The output power of 77 GHz radar transmitter is higher than 13.99 dBm and the magnitude of the reference spur relative to the carrier is -36.45 dBc. The phase noise is -81 dBc/Hz at 1 MHz offset frequency from the carrier.

• Korean Journal of Microbiology
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• v.41 no.2
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• pp.125-128
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• 2005

A 16S ribosomal RNA gene from S. chungbukensis DJ77 has been sequenced. This sequence had a length of 1,502 bp and was extended for 29 bp at 5' and for 37 bp at 3' from the partial sequence (1,435 bp) registered in 2000 year. Besides, 1 bp was newly added near to the 3' end. We made the secondary structure of the 16S rRNA based on E. coli model and found four specific regions. We found constant and variable regions in genus Sphingomonas as the result of multiple alignment of 16S rRNA gene sequences from Sphingomonas spp. and S. chungbukensis DJ77. We found a stem loop structure in S. chungbukensis DJ77, which was only discovered in C. jejuni to date. It showed the structural agreement despite the difference of the sequences from the both organisms. Finally, S. chungbukensis DJ77 belonged to cluster II (Sphingobium) group, after the classification using phylogenetic analysis and nucleotide signature analysis.

• Journal of the Chungcheong Mathematical Society
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• v.28 no.4
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• pp.537-543
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• 2015

In [9], the authors determine an infinite class of non-unimodal Gorenstein sequence, which includes the example $$\bar{h}_1\text{ = (1, 125, 95, 77, 71, 77, 95, 125, 1)}$$. They raise a question whether there is a Gorenstein algebra with Hilbert function $$\bar{h}_2\text{= (1, 125, 95, 77, 70, 77, 95, 125, 1)}$$, which has remained an open question. In this paper, we prove that there is no Gorenstein algebra with Hilbert function $\bar{h}_2$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.682-684
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• 2003

In this paper, we have designed the p-type SiGe MOSFET and analyzed the electrical characteristics over the temperature range of 300K and 77K. When the gate voltage is biased to -1.5V, the threshold voltage values are -0.97V and -1.15V at room temperature and 77K, respectively. We know that the operating characteristics of SiGe MOSFET is superior to the basic Si MOSFET which the threshold voltage is -1.36V.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.474-477
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• 2003

In this paper, we have designed the p-type SiGe MOSFET and analyzed the electrical characteristics over the temperature range or 300K and 77K. When the gate voltage is biased to -1.5V, the threshold voltage values are -0.97V and -1.15V at room temperature and 77K, respectively. We know that the operating characteristics of SiGe MOSFET is superior to the basic Si MOSFET which the threshold voltage is -1.36V.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.87-90
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• 1989

The force acting on high Tc superconductors at 77K is measured and analyzed numerically. Both values are compared, and the difference between them is discussed. The forces, acting on a superconducting disk (thickness:1[mm], diameter:12[mm]) in an axially-symmetric magnetic field produced by a solenoid or a permanent magnet ring, are measured at 77K. The disk is an YBCO high Tc superconductor. The discrete surface current method(DSCM) is formalized for an axially-symmetric magnetic field. The forces of the superconducting disk in the magnetic field are analyzed using the DSCM, assuming that the disk is a perfect diamagnetic body. When the bottom side of the disk is separated 8[mm] from the top side of the solenoid, and the magnetic field applied on the center of the bottom side of the disk is 96[G], the measured value and the calculated value of the force are 96 and 496[mgf], respectively. The difference between them is caused by a non-perfect diamagnetism of the high Tc superconductor at 77K. It is proposed that a real force acting on high Tc superconductors at 77K can be estimated on the basis of a measured magnetic susceptibility of the high Tc superconductor at 77K and a calculated force of a perfect diamagnetic body.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.9
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• pp.915-921
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• 2013

This work presents a 77 GHz low noise amplifier(LNA) for automotive radar systems using 65 nm RF CMOS process. The LNA is composed of three stage common source amplifiers and includes transmission line matching networks. To reduce the time for three dimensional EM simulation, we optimize the transmission line impedance matching network using a pre-built EM library. The proposed compact simulation technique is confirmed by measurement results. The peak gain of the LNA is 10 dB at 77 GHz and input/output return losses are below -10 dB around the design frequency.