• Korean Journal of Optics and Photonics
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• v.31 no.5
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• pp.213-217
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• 2020

In this study we report a wet-etching-based fabrication method for adiabatic optical-fiber tapers (OFTs), and describe their adiabaticity and HE₁₁ mode evolution at a wavelength of 1550 nm. The profile of the fabricated system satisfies the adiabaticity properties well, and the far-field pattern from the etched OFT shows that the fundamental HE₁₁ mode is maintained without a higher-order mode coupling throughout the tapers. In addition, the measured far-field pattern agrees well with the simulated result. The proposed adiabatic OFTs can be applied to a number of photonic applications, especially fiber-chip packages. Based on the fabricated adiabatic OFT structures, the optical transmission to the inversely tapered silicon waveguide shows large spatial-dimensional tolerances for 1 dB excess loss of ~60 ㎛ (silicon waveguide angle of 1°) and insertion loss of less than 0.4 dB (silicon waveguide angle of 4°), from the numerical simulation. The proposed adiabatic coupler shows the ultrabroadband coupling efficiency over the O- and C-bands.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.105-116
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• 1998

Purpose In this study, We observed the recovery process in the ability to move in the hind limbs of the rats whose spinal cord injuries were treated by Radix acouniti(RA). The purpose of this study is to see the effects of Radix acouniti(RA) water extract on the contraction of rat's spinal cord injury. Procedure First, the rats were subjected to hemisectional spinal cord injuries by a scalpel blade. Those rats, then, were divided into three groups: Sham operated rats group and the experimental group, which received the Radix acouniti(RA) water extract, and the control group, which had no treatment. Their recovery in the ability to walk was observed by the Open Field Test (OFT) for 14 days after the injuries. Method The OFT was applied at four points: the hip, knee, ankle joint, and the tail. Each joint was given a movement rating of from 0 to 3, depending on the amount of movement. A movement rating of 0 designates no movement, a 1 designates slight movement, a 2 designates increased movement, and a 3 designates active movement. Slight movement is defined as a joint displaying less than or equal to 30% of that joint range, increased movement is displaying less than or equal to 60% of that joint's range, and active movement is greater than or equal to 90% of that joint's range. Tail movement is also graded on a scale of 0 to 3. A rating of 0 indicates that the tail is down 100% of the time, one of 1 indicates that the tail is down more than 10%, one of 2 shows that the tail is down less than 50% but more than 10% of the time, and one of 3 shows that the tail is down less than 10% of the time. All four ratings were added together and then averaged to arrive at a single score. Results The sham group which did not go through spinal cord injuries showed near normal results on all 3 joints and tail from right after the operation, which one would expect. The RA oral application group showed more effective recovery of movememt function than the control group around 4 days after the spinal cord injuries. However, after 14 days, both groups displayed almost the same degree of movement recovery. The results of this study are summarized as follows: 1. After 14days the spinal cord injuries, movement was recovered in sham operated group, control group, and experimented group in the hip, the knee, the tail and then the ankle of rats, in that order. 2. Around 7 days after the spinal cord injuries, the experimental group proved the effectiveness of the therapy in terms of movement recovery. 3. The level of ALT, ALP, AST in RA treated group was slightly increased. 4. The level of BUN and creatinine in RA treated group was slightly increased. The above results indicate that RA therapy at an early stage can bring about better movement recovery in patients with spinal cord injuries from traffic accidents or industrial disasters. But there is apparent side effect of RA on clinical, therefore the study on this should be continued.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.551-561
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• 2009

FH system is very robust to the jamming interference. OFDM system is very good for the high speed communication system. But, it has high PAPR. SC-FDMA system based on OFT-spread OFDM was proposed to reduce high PAPR. Therefore, in this paper, we like to introduce the FH system into SC-FDMA system, which can be best solution to the jamming hostile environment and for the high power efficiency. Also, OFDM is very sensitive to ICI. Especially, ICI generated by frequency offset and phase noise breaks the orthogonality among sub-carriers, which seriously degrades the system performance. We analyze the performance of the FH SC-FDMA system in the PBJ and MTJ channel. In this paper, the ICI effects caused by phase noise, frequency offset and Doppler effects are analyzed and we like to propose the PNFS algorithm in the equalizer to compensate the ICI influences. Through the computer simulations, we can confirm the performance improvement.

• Journal of Life Science
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• v.30 no.4
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• pp.321-330
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• 2020

The aim of this study was to investigate the effect of copper (II) chloride (CuCl₂) on zebrafish. Zebrafish were exposed to various CuCl₂ concentrations and subjected to different exposure times to determine the median lethal concentration (LC₅₀) values. To evaluate stress responses, we measured whole-body cortisol levels and behavioral parameters using the open field test (OFT) or the novel tank test (NTT). The zebrafish were exposed to CuCl₂ solution at concentrations of 1.5-150 ㎍/l or a vehicle for 1 hr before behavioral tests or sample collection for whole-body cortisol. The LC₅₀ values were 30.3, 25.3, and 14.8 ㎍/l at 24, 48, and 96 hr, respectively. The NTT showed that mobility, velocity, and distance covered were significantly lower in zebrafish exposed to CuCl₂ than in the control group (p<0.05), while the turn angle was significantly higher in zebrafish exposed to a CuCl₂ concentration of 150 ㎍/l than in the control group (p<0.05). The OFT also showed that mobility, velocity, and distance covered were significantly lower and the turn angle and meandering were significantly higher in zebrafish exposed to all concentrations of CuCl₂ than in the control group (p<0.05). The whole-body cortisol levels were significantly higher in zebrafish exposed to CuCl₂ than in the control group (p<0.05). These results suggest that exposure to lethal CuCl₂ concentrations induces an intense toxic and stress response in zebrafish, causing behavioral changes and increasing whole-body cortisol levels.

• Korean Journal of Medicinal Crop Science
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• v.24 no.5
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• pp.341-350
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• 2016

Background: Prenatal exposure to infectious and/or inflammatory insults can increase the risk of developing neuropsychiatric disorder such as bipolar disorder, autism, and schizophrenia later in life. We investigated whether Valeriana fauriei (VF) treatment alleviates prepulse inhibition (PPI) deficits and social interaction impairment induced by maternal immune activation (MIA). Methods and Results: Pregnant mice were exposed to polyriboinosinic-polyribocytidilic acid (5 mg/kg, viral infection mimic) on gestational day 9. The adolescent offspring received daily oral treatment with VF (100 mg/kg) and injections of clozapine (5 mg/kg) for 30 days starting on the postnatal day 35. The effects of VF extract treatment on behavioral activity impairment and protein expression were investigated using the PPI analysis, forced swim test (FST), open field test (OFT), social interaction test (SIT), and immunohistochemistry. The MIA-induced offspring showed deficits in the PPI, FST, OFT, and SIT compared to their non MIA-induced counterparts. Treatment with the VF extract significantly recovered the sensorimotor gating deficits and partially recovered the aggressive behavior observed in the SIT. The VF extract also reversed the downregulation of protein expression induced by MIA in the medial prefrontal cortex. Conclusions: Our results provide initial evidence of the fact that the VF extract could reverse MIA-induced behavioral impairment and prevent neurodevelopmental disorders such as schizophrenia.

• Journal of Oriental Neuropsychiatry
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• v.30 no.3
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• pp.209-220
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• 2019

Objectives: As a general emotion, everyone can temporarily experience depression, but depressive disorder is a disease that excessively affects daily life. Among the various causes of depression, the deficiency of monoamine-based neurotransmitters such as serotonin and epinephrine are considered significant. Thus, antidepressants that target monoamines are used frequently. However, side effects such as nausea, vomiting, insomnia, anxiety, and sexual dysfunction are observed. Thus, it is necessary to develop a new therapeutic agent with fewer side effects. In this study, we investigated the antidepressant effect of JG02, used to treat depression by normalizing the flow of qi (氣) in Korean medicine. Methods: C57BL/6 mice were selected and randomly divided into six groups: normal, control, amitriptyline, and JG02 (50, 125, 250 mg/kg), respectively. Except for normal, depression was induced by applying restraint stress at the same time for six hours daily for 14 consecutive days. Saline, amitriptyline or JG02 samples were orally administered two hours before applying the stress. After that, a forced swimming test and an open field test were performed. Additionally, serum corticosterone, serotonin mRNA, BDNF mRNA, and protein in the hippocampal region were measured and compared. Results: JG02 decreased immobility time rate in the FST and increased the zone transition number and travel distance in the OFT. Also, JG02 inhibited the release of serum corticosterone, and increased serotonin, BDNF gene expression, and BDNF protein in the hippocampus. Conclusions: In this study, JG02 showed significant antidepressant effects on the chronic restraint stress mice model. When further research is performed based on JG02, the development of a new antidepressant is considered highly possible.

• Journal of the Korean Ceramic Society
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• v.39 no.3
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• pp.222-225
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• 2002

Microwave dielectric properties of the layered and functionally graded materials (FGMs) of $Mg_{0.93}Ca_{0.07}TiO_3$ (MCT) and $(Ca_{0.3}Li_{0.14}Sm_{0.42})TiO_3$(CLST) were investigated as a function of the volume ratio of two components. Dielectric constant was decreased with an increase of the volume ratio of MCT which had a lower dielectric constant thant CLST. For the layered FGMs specimens, the difference of thermal expansion coefficients between two components induced thermal strain to dielectric layers, which was confirmed by the plot of ${\Delta}$k (X-ray diffraction peak width0 versus k (scattering vector) using the double-peak Lorentzian function, f(x). Quality factor of the specimens was affected by the thermal strain of dielectric layer, especially MCT layer. For the specimen with the volume ratio of MCT/CLST = 2, the qulaity factor of the specimen showed a minimum value due to the maximum thermal strain fo MCT layer.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.2
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• pp.65-75
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• 2010

In 2014, Japan is scheduled to launch GCOM(Global Change Observation Mission)-C for the global change observation mission, where SGLI(Second-generation Global Imager) is planned for optical multi-channel observation ofa radiation budget and a carbon cycle. Depending on the spectral channels, SGLI consists ofS GLI-VNR(Visible Near IR) and SGLI-IRS(IR Scanning). Their main design schemes are mostly based upon those ofthe previous instruments ever developed in Japan, which is intended to reduce the development risk for the advanced performance. Accordingly, for the better understanding ofSG LI, the paper reviews the history oft he Japanese optical payloads from two different views: VNR and IR. Through the review, a comparison among the Japanese optical instruments is made to distinguish the development trend toward SGLI ofGC OM-C.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1324_1325
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• 2009

The heterolayered $BaTiO_3/(Bi_{0.5}Na_{0.5})TiO_3$ thick films were fabricated by screen printing techniques on alumina substrates electrodes with Pt. We report the improved ferroelectric properties in the heterolayered teteragonal/rhombohedral structure composed of the $BaTiO_3$ and the $(Bi_{0.5}Na_{0.5})TiO_3$ thick films. We investigated the effects of deposition conditions on the structural and electrical properties of the heterolayered BNT/BT thick films. The structural and electrical properties of the heterolayered BNT/BT thick films were studied. All PZT heterolayered thin films show dense and homogeneous structure without the presence of the rosette structure. The dielectric constant, loss and remanent polarization oft heheterolayered BNT/BT thick films were superior to those of single composition $BaTiO_3$ and $(Bi_{1/2}Na_{1/2})TiO_3$, and those values for the heterolayered BNT/BT thick films sintered at $1100^{\circ}C$ were 916, 0.79 and $12.63{\mu}C/cm^2$.

• Geotechnical Engineering
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• v.14 no.2
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• pp.9-20
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• 1998

The earthquake-induced liquefaction of ground brings high possibility of failure of lifeline. If subsurface liquefaction is detected immediately after an earthquake the damage caused by the failure of lifeline can be reduced. The goal is achieved by deploying many accelerometers in the area of possible liquefaction and collecting records through a wireless network. This paper attempts to develop a measure to interpret the collected data oft surface motion and to assess the thickness of liquefied layers. For this purpose. both analysis of earthquake records and shaking table tests on model ground were carried out. It was shown that the thickness of liquefied layers can be assessed by using the maximum acceleration and the spectrum intensity at the surface.