• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.942-944
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• 2009

Blue phase shows several different reflection colors from the randomly oriented domains and crystal direction. Also there are variations in the size of domains. The domain size is dependent on the temperature gradient. With smaller cooling rate of temperature, the domain size was increased compared with rapid cooling. With injection of light of specific wavelength, we find that the diffraction patterns were occurred around the light spot in the cell of blue phase. It was supposed to be from the matching of the phase retardation and domain size. However, actually the diffraction pattern is reflecting the lattice structure in double twist of the blue phase. The lattice constant from the radius of diffraction patterns shows very similar one from the reflection spectrum, which indicates the internal lattice constant in double twist of the blues phase.

• Korean Journal of Optics and Photonics
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• v.4 no.1
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• pp.22-27
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• 1993

We investigate the phase modulation effects on the OTFs of a binocular objective which is made in Korea.The OTFs are calculated from design data for FOV $0^{\circ}$ and $1.5^{\circ}$.The phase modulation is carried out by giving phase retardation $\pi$ on the aperture. The areas where the phases are retarded $\pi$ on the aperture are of an annular type. The OTFs of phase modulated aperture are also compared with that of unmodulated one. The OTFs of an aberration loaded system can be improved by proper phase modulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.255-260
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• 1998

Behavior of solid phase crystallizations (SPC) of RF sputtered and LPCVD amorphous hydrogenated silicon film were investigated. LPCVD films showed the higher degree of crystallinity and larger grain size than sputtered films. The applicable degree of crystallinity was also obtained from sputtered films. The deposition method of amorphous silicon film influenced the behavior of post annealing SPC. Observed degree of crystallinity of sputtered films strongly depended on the partial pressure of hydrogen in deposition. The higher deposition temperature of sputtering provided the better crystallinity after SPC. Due to the high degree of poly-crystallinity, the retardation of larger grain growth was observed on sputtering film.

• Journal of The Korean Dental Society of Anesthesiology
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• v.12 no.2
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• pp.125-129
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• 2012

Dental treatment under general anesthesia is considered for behavioral control of disabled patients who have severe anxiety or involuntary movement. However, in case of simple treatment, inhalation or intravenous sedation, which has earlier onset and recovery, is preferred. Conventionally, nitric oxide is used for inhalation sedation, nowadays sevoflurane can also be used due to easily titratable for controllable effect and less complications. In this case report, two patients with mental retardation required simple dental treatment. Deep sedation with inhaled sevoflurane were successfully employed and patients were discharged without any complications.

• Korean Journal of Optics and Photonics
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• v.13 no.5
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• pp.408-413
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• 2002

We demonstrated a polarization dependent type 2$\times$2 optical switch, using a binary reflection type SLM. Reflection type FLC was used as a half wave retardation plate. Two inputs were controlled by each SLM for the desired output direction. In conclusion, in the "1" state the average optical loss was 6.6 ㏈, and in the "0" state the average optical loss was 14.6 ㏈, and measured the switching speed as 75 $mutextrm{s}$. By using this method, a polarization dependent type 2$\times$2 optical switch can be demonstrated and the possibility of a 4-port WDM optical switch also verified.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.22 no.4
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• pp.392-399
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• 2019

Wilson disease a rare autosomal recessive inherited disorder of copper metabolism, is characterized by excessive deposition of copper in the liver, brain, and other tissues. Wilson disease is often fatal if it is not recognized early and treated when it is symptomatic. Gitelman syndrome is also an autosomal recessive kidney disorder characterized by low blood levels of potassium and magnesium, decreased excretion of calcium in the urine, and elevated blood pH. Hereditary sensory autonomic neuropathy type IV (HSAN-IV), a very rare condition that presents in infancy, is characterized by anhidrosis, absence of pain sensation, and self-mutilation. It is usually accompanied by developmental delay and mental retardation. We report a case of Wilson disease manifested as fulminant hepatitis, acute pancreatitis, and acute kidney injury in a 15-year-old boy comorbid with HSAN-IV and Gitelman syndrome. Such concurrence of three genetic diseases is an extremely rare case.

• Journal of Interdisciplinary Genomics
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• v.5 no.1
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• pp.5-11
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• 2023

β-ureidopropionase (β-UP) is an enzyme that catalyzes the final step in the pyrimidine degradation pathway, which converts β-ureidopropionate and β-ureidoisobutyrate into β-alanine and β-aminoisobutyrate, respectively. β-UP deficiency (UPB1D; OMIM # 613161) is an extremely rare autosomal recessive inborn error disease caused by a mutation in the UPB1 gene on chromosome 22q11. To date, approximately 40 cases of UPB1D have been reported worldwide, including one case in Korea. The clinical manifestations of patients with UPB1D are known to be diverse, with a very wide range of manifestations being previously reported; these manifestations include completely asymptomatic, urogenital and colorectal anomalies, or severe neurological involvement, including global developmental delay, microcephaly, early onset psychomotor retardation with dysmorphic features, epilepsy, optic atrophy, retinitis pigmentosa, severely delayed myelination, and cerebellar hypoplasia. Currently, diagnosis of UPB1D is challenging as neurological manifestations, MRI abnormalities, and biochemical analysis for pyrimidine metabolites in the urine, plasma, and cerebrospinal fluid also need to be confirmed by UPB1 gene mutations. Overall, treatment of patients with UPB1D is palliative as there is still no definitive curative treatment available.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.33-42
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• 2000

Adsorption onto the surfaces of solid particles is a well known phenomenon that causes the retardation effect of heavy metals in soils. For adequate remediation of soil and groundwater contamination, it is important to investigate the mobility of heavy metals that largely depends on pH conditions in the soil water since adsorption of heavy metals is pH-dependent. In this study, we investigated the transport of Zn ion under various pH conditions in a sandy soil by conducting batch and column tests. The batch test was performed using the standard procedure of equilibrating fine fractions collected from the soil with eleven different initial $ZnCl_2$ concentrations, and analysis of Zn ion in the equilibrated solutions using ICP-AES. The column test consisted of monitoring the concentrations of soil solutions exiting the soil column with time known as a breakthrough curve (BTC). We injected respectively $ZnCl_2$ and KCl solutions with the concentration of 10 g/L as a tracer in a square pulse type under three different pH conditions (7.7, 5.8, 4.1) and monitored the flux concentration at the exit boundary using an EC meter and ICP-AES. The resident concentration was also monitored at the 10cm-depth by Time Domain Reflectometry (TDR). The results of batch test showed that ion exchange process between Zn and other cations (Ca, Mg) was predominant. The retardation coefficients obtained from adsorption isotherms (Linear, Freundlich, Langmuir) resulted in the various values ranging from 1.2 to 614.1. No retardation effect but ion exchange was found for the BTCs under all pH conditions. This can be explained by the absence of other cations to desorb Zn ion from soil exchange sites under the conditions of ETC experiment imposing blank water as leachate in steady-state flow. As pH decreased, the peak concentration of Zn increased due to the competition of Zn with hydrogen ions ($H^+$) and the concentrations of other cations decreased. The peak concentration of Zn was increased by 12.7 times as pH decreased from 7.7 to 4.1.

• Journal of Preventive Medicine and Public Health
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• v.22 no.3 s.27
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• pp.368-379
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• 1989

The relationship between mercury level of hair and mental retardation was investigated. The 297 subjects with mental retardation were drawn from two schools providing special educational services, one, consisted of children living in an orphan home, another, children with parents. The 117 centre] subjects were drawn from whom had got average or above average academic achivement in a regular elementary school. Hair sample were taken from the nape of the neck and the mercury analysis was carried out on an atomic absorption spectrophotometer(IL 551). There was no relationship between mercury contents and age, and there was a statistically significant difference in mercury contents between male and female in the mentally retarded children living with parents. Children in the retarded group had significantly higher mercury contents compared with control group except the female group with parents. Also, the mercury levels in the retarded group living in an orphan home were significantly higher than that of the retarded group with parents. The concomitant diseases were Down's syndrome, epilepsy, cerebral palsy and autism. There were statistically significant differences in hair mercury levels in the cases of accompanying Down's syndrome and cerebral palsy in male and Down's syndrome and autism in female compared with the control group of the same sex. The most accompanying handicap was speech disturbance(40.7%) and the others were crippled, emotional disturbance etc. The percentages of double handicap were 66.7% among 6 persons exceeding 6ppm of their hair mercury contents. 10.4% among $3{\sim}6$ ppm and 15.7% among the group of 3ppm or less. The findings of this study suggest that the more opportunities of exposure to mercury in mentally retarded children may have occurred, so it can not be excluded the possibility of mercury as a contributing factor to mental retardation. Therefore, the causal relationship between mercury levels and mental retardation should be established through the examinations about their living environments, dietary pattern, eating habit etc.

• Korean Journal of Optics and Photonics
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• v.31 no.1
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• pp.1-6
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• 2020

The chest wall, an organ directly affected by environmental particles through respiration, consists of ribs, a pleural layer and intercostal muscles. To diagnose early and treat disease in this body part, it is important to visualize the details of the chest wall, but the structure of the pleural layer cannot be seen by chest computed tomography or ultrasound. On the other hand, optical coherence tomography (OCT), with a high spatial resolution, is suited to observe pleural-layer response to talc, one of the fine materials. However, intensity-based OCT is weak in providing information to distinguish the detailed structure of the chest wall, and cannot distinguish the reaction of the pleural layer from the change in the muscle by the talc. Polarization-sensitive OCT (PS-OCT) takes advantage of the fact that specific tissues like muscle, which have optical birefringence, change the backscattered light's polarization state. Moreover, the birefringence of muscle associated with the arrangement of myofilaments indicates the muscle's condition, by measuring retardation change. The PS-OCT image is interpreted from three major perspectives for talc-exposure chest-wall imaging: a thickened pleural layer, a separation between pleural layer and muscle, and a phase-retardation measurement around lesions. In this paper, a rabbit chest wall after talc pleurodesis is investigated by PS-OCT. The PS-OCT images visualize the pleural layer and muscle, respectively, and this system shows different birefringence of normal and damaged lesions. Also, an analyisis based on phase-retardation slope supports results from the PS-OCT image and histology.