• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.63 no.3
• /
• pp.371-375
• /
• 2014

In this paper, we compared the performances of the Right Handed Transmission Line (RHTL) and the Left Handed Transmission Line (LHTL) phase shifters as a frequency translator. Unlike other phase shifters, both phase shifters show a $0^{\circ}-360^{\circ}$ phase variation for a broadband frequency and compact in size which are ideal to use as a frequency translator. For the performance comparison, we fabricated both a RHTL and a LHTL phase shifter to cover 1.5 GHz - 2.4 GHz range with the whole $360^{\circ}$ phase variation. For the frequency range, a LHTL based frequency translator showed a much better performance whose Spurious Free Dynamic Range (SFDR) is 4dB - 17dB higher than the RHTL based frequency translator when the sawtooth modulation freqncy is 11 kHz. This is due to the linear phase-voltage variation of LHTL phase shifter. Furthermore, the LHTL phase shifter shows a less insertion loss and a insertion loss variation than the RHTL phase shifter. Overall, the LHTL based frequency translator outperformed RHTL based freqency translator.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.478-483
• /
• 2003

In this paper, in order to fabricate the circularly polarized diversity system which will mitigate multipath fading, 5.8GHz band microstrip array antenna were designed and fabricated. These antenna were designed using Ensemble 6.0 program and the fabricated antenna were vertical and horizontal polarized antenna, left-handed circularly polarized antenna, and right-handed circularly polarized antenna. The designed antenna parameters included S11 and impedance characteristics of fabricated antenna were measured using Network Analyzer(8753ES). From the measurement results, the S11 for each polarization antenna at resonance frequency of 5.8GHz band was showed -38dB, -44dB, and -50dB respectively and it was similar to the simulation result, and also the impedance can be matched at $50{\Omega}$. In order to compare polarization characteristics, broadband measurement was also conducted in this paper.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.12C
• /
• pp.1299-1305
• /
• 2002

Tx/Rx dual microstrip array antennas for satellite communications are designed, fabricated, and measured in this paper. They have a Right Handed Circular Polarization (RHCP) for Tx and Left Handed Circular Polarization (LHCP) for Rx. Two stacked patches are used for wideband characteristics and corner-truncated square patches are adopted for a circular polarization. To enhance bandwidth characteristics of a circular polarization, 2${\times}$1 sequential rotation mays are applied. From the measured results, 8${\times}$1 microstrip may antennas have a good agreement with those of the simulation. Therefore the array antennas are applicable to satellite communication antennas, active phased may antennas, and radiators in other antennas.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.46 no.2
• /
• pp.126-133
• /
• 2009

In this paper, The planar waveguide slotted antenna is presented for a satellite communication of vehicles. In stead of the microstrip patch array antenna having a dielectric loss and a feeding loss, the proposed antenna has the 3-layered waveguide feeding network structure for assembling easily. Also this antenna can receive mechanically both RHCP and LHCP transmitted from a satellite using a polarizer made from a thin single layer film. The Gain of the proposed 4X8 array antenna is 27.5dB and the gain of 8X16 array antenna is 32dB.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.11
• /
• pp.3719-3726
• /
• 2012

Formation of Z-DNA, a left-handed double helix, from B-DNA, the canonical right-handed double helix, occurs during important biological processes such as gene expression and DNA transcription. Such B-Z transitions can also be induced by high salt concentration in vitro, but the changes in the relative stability of B-DNA and Z-DNA with salt concentration have not been fully explained despite numerous attempts. For example, electrostatic effects alone could not account for salt-induced B-Z transitions in previous studies. In this paper, we propose that the B-Z transition can be explained if counterion entropy is considered along with the electrostatic interactions. This can be achieved by conducting all-atom, explicit-solvent MD simulations followed by MM-PBSA and molecular DFT calculations. Our MD simulations show that counterions tend to bind at specific sites in B-DNA and Z-DNA, and that more ions cluster near Z-DNA than near B-DNA. Moreover, the difference in counterion ordering near B-DNA and Z-DNA is larger at a low salt concentration than at a high concentration. The results imply that the exclusion of counterions by Z-DNA-binding proteins may facilitate Z-DNA formation under physiological conditions.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.8
• /
• pp.1212-1216
• /
• 2015

In this paper, we compared the performance of the Right Handed Nonlinear Transmission Line (RH-NLTL) and Left Handed Nonlinear Transmission Line (LH-NLTL) as a harmonic generator. For a performance comparison, we fabricated both a RH-NLTL and a LH-NLTL harmonic generator whose operational bandwidth is from 0.5 GHz to 1.5 GHz. Under the each condition for the RH-NLTL and the LH-NLTL to maximize second harmonic, the output power of the second harmonic was 9.33 dB lower than the input power for the RH-NLTL and 12.67 dB lower than the input power for the LH-NLTL. Under the each condition for the RH-NLTL and the LH-NLTL to maximize third harmonic, the output power of the third harmonic was 13.33 dB lower than the input power for the RH-NLTL and 14.83dB lower than the input power for the LH-NLTL. Also, we have observed that, generatlly, a RH-NLTL is useful in generating various multiple harmonics and a LH-NLTL is useful in generating a specific order of harmonic by adjusting a proper DC vias, input frequency and input power. These tendencies could be a good guideline to use NLTLs as a frequency multiplier.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.9
• /
• pp.929-933
• /
• 1997

Morphological studies in the micro-end-to-end (m-E-E) and micro-side-by-side (m-S-S) aggregations were conducted by using of scanning electron microscope (SEM) for the samples precipitated by heating of the end-products of the transition of FormⅡ (left-handed helix, three peptides per turn, 31) Form Ⅰ (right-handed helix, 3.3 peptides per turn, 103) in poly(L-proline) (PLP) in acetic acid(water)-propanol (1:9 v/v) solvent. The observed morphology for the solide state shows a rope (or super helical) type and pebbles type aggregate for the (m-E-E) and (m-S-S) aggregate respectively. The viscosities were also measured during the heat-precipitation in order to elucidate the process of formation of the rope- and pebbles-type aggregates. The result for the (m-E-E) aggregations exhibit two steps, i.e., at first, the viscosity increases with time (step 1), thereafter it decrease until attain the last value (step 2). But the (m-S-S) aggregations show only one step in the decreases in viscosity. On the bases of all experimental results it is possible to propose a reasonable mechanism for the formation of the two types of aggregates of the (m-E-E) and (m-S-S).

• Molecules and Cells
• /
• v.45 no.8
• /
• pp.522-530
• /
• 2022

Transposable elements (TEs) account for approximately 45% of the human genome. TEs have proliferated randomly and integrated into functional genes during hominoid radiation. They appear as right-handed B-DNA double helices and slightly elongated left-handed Z-DNAs. Human endogenous retrovirus (HERV) families are widely distributed in human chromosomes at a ratio of 8%. They contain a 5'-long terminal repeat (LTR)-gag-pol-env-3'-LTR structure. LTRs contain the U3 enhancer and promoter region, transcribed R region, and U5 region. LTRs can influence host gene expression by acting as regulatory elements. In this review, we describe the alternative promoters derived from LTR elements that overlap Z-DNA by comparing Z-hunt and DeepZ data for human functional genes. We also present evidence showing the regulatory activity of LTR elements containing Z-DNA in GSDML. Taken together, the regulatory activity of LTR elements with Z-DNA allows us to understand gene function in relation to various human diseases.

• Clinics in Shoulder and Elbow
• /
• v.21 no.4
• /
• pp.252-255
• /
• 2018

A 51-year-old male who is right-handed visited the outpatient for right fingers-drop. The patient's fingers, including thumb, were not extended on metacarpophalangeal joint. The active motion of the right wrist was available. The electromyography and nerve conduction velocity study were consistent with the posterior interosseous neuropathy. Further evaluation was done with the magnetic resonance imaging for finding the space-occupying lesion or any possible soft tissue lesion around the radial nerve pathway. On magnetic resonance imaging, the ganglion cyst, which was about 1.8 cm in diameter, was observed on the proximal part of the superficial layer of the supinator muscle (Arcade of Frohse). The surgical excision was done on the base of ganglion cyst at the base of stalk of cyst which looked to be connected with proximal radioulnar joint capsule. The palsy had completely resolved when the patient was observed on the outpatient department a month after the operation.

• Investigative Magnetic Resonance Imaging
• /
• v.3 no.1
• /
• pp.53-59
• /
• 1999

Purpose : To evaluate the usefulness of functional MR imaging (fMRI) for language mapping and determination of language lateralization. Materials and Methods : Functional maps of the language area were obtained during word generation tasks and decision task in ten volunteers (7 right handed, 3 left-handed). MR examinations were performed at 1.5T scanner with EPI BOLD technique. Each task consisted of three resting periods and two activation periods with each period of 30 seconds. Total acquisition time was 162 sec. SPM program was used for the postprocessing of images. Statistical comparisons were performed by using t-statistics on a pixel-by- pixel basis after global normalization by ANCOVA. Activation areas were topographically analyzed (p>0.001) and activated pixels in each hemisphere were compared quantitatively by lateralization index. Results : Significant activation signals were demonstrated in 9 of 10 volunteers. Activation signals were found in the premotor and motor cortices, the inferior frontal, inferior parietal, and mid-temporal lobes during stimulation tasks. In the right handed seven volunteers, activation of language areas was lateralized to the left side. Verb generation task produced stronger activation in the language areas and higher value of lateralization index than noun generation task or decision task. Conclusion : fMRI could be a useful non-invasive method for language mapping and determination of language dominance.