• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.1009-1012
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• 2000

In this paper, we have designed and fabricated power PHEMT’s with an unit gate width of 80$\mu\textrm{m}$ and 4 fingers, and MIMIC power amplifiers using the PHEMT’s as well. The PHEMT’s have a 0.2$\mu\textrm{m}$ gate length and source to drain spacing of 3$\mu\textrm{m}$. The characteristics of the fabricated PHEMT’s are 4.08dB of S$\sub$21/ gain at the 35GHz and 317mS/mm of gm, and 62GHz of f$\sub$T/ and 120GHz of f$\sub$max/. The designed and fabricated MIMIC’s power amplifiers with 6 PHEMT’s and MIN capacitors were fully passivated by 1000 Α of Si$_3$N$_4$ film for higher performance and surface protects. The chips were processed using the MINT processes, and size was 3.25 ${\times}$ 1.8$\textrm{mm}^2$. The fabricated MIMIC power amplifiers have RF characteristics such as 11.25dB of S$\sub$21/ gain, 11.37dB of input return-loss and 12.69dB of output return-loss at the 34.55GHz.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.35-41
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• 2013

Metabolic analysis of CR6 interacting factor 1 (Crif1) deficient mouse embryonic fibroblasts with impaired oxidative phosphorylation has been carried out using LC-MS/MS and GC-MS methods. Metabolic profiles of the Crif1 deficient cells were comprehensively obtained for the first time. Loss of oxidative phosphorylation functions in mitochondria resulted in cancer-like metabolic reprogramming with consumption of majority of glucose carbon from up-regulated glycolysis to produce lactate, suppressed utilization of glucose carbon in the TCA cycle, increased amounts of amino acids. The changes in metabolic profile of the Crif1 deficient cells are most probably a consequence of metabolic reprogramming to meet the needs of energy balance and anabolic precursors in compensation for the loss of major oxidative phosphorylation functions.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.113-116
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• 2004

We developed internal and external type sensor to measure ultra-high frequency (UHF) partial discharge (PD) in 170 kV gas-insulated switchgears (GIS). We also manufactured a PD-generator to verify and measure the detection sensitivity of those sensors. We measured the output power of the UHF PD sensors induced by PDs of 5 pC using the PD-generator. We measured UHF propagation loss of an 170 kV GIS for optimal arrangement of the sensors. We used swept UHF signal from a network analyzer into the GIS to measure the loss of various components of the GIS.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.102-103
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• 2007

In order to apply resistive superconducting fault current limiters into electric power systems, the urgent issues to be settled are as follows, such as initial installation price of SFCL, operation and maintenance cost due to ac loss of superconductor and the life of cryostat, and high voltage and high current problems. The ac loss and high cost of superconductor and cryostat system are main bottlenecks for real application. Furthermore in order to increase voltage and current ratings of SFCL, a lot of superconductor components should be connected in series and parallel which resulted in extreme high cost. Thus, in order to make practical SFCL, we designed novel hybrid SFCL which combines superconductor and conventional electric equipment including vacuum interrupter, power fuse and current limiting reactor. The main purpose of hybrid SFCL is to drastically reduce total usage of superconductor by adopting current commutation method by use of superconductor and high fast switch. Consequently, it was possible to get the satisfactory test results using this method, and further works for practical applications are in the process.

• Journal of Genetic Medicine
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• v.16 no.1
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• pp.15-18
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• 2019

SHORT syndrome is an extremely rare congenital condition due to a chromosomal mutation of the PIK3R1 gene found at 5q13.1. SHORT is a mnemonic representing six manifestations of the syndrome: (S) short stature, (H) hyperextensibility of joints and/or inguinal hernia, (O) ocular depression, (R) Rieger anomaly, and (T) teething delay. Other key aspects of this syndrome not found in the mnemonic include lipodystrophy, triangular face with dimpled chin (progeroid facies, commonly referred to as facial gestalt), hearing loss, vision loss, insulin resistance, and intrauterine growth restriction (IUGR). 3q duplication syndrome is rare syndrome that occurs due to a gain of function mutation found at 3q25.31-33 that presents with a wide array of manifestations including internal organ defects, genitourinary malformations, hand and foot deformities, and mental disability. We present a case of a 2 year and 3 month old male with SHORT syndrome and concurrent 3q duplication syndrome. The patient presented at birth with many of the common manifestations of SHORT syndrome such as bossing of frontal bone of skull, triangular shaped face, lipodystrophy, micrognathia, sunken eyes, and thin, wrinkled skin (progeroid appearance). Additionally, he presented with findings associated with 3q duplication syndrome such as cleft palate and cryptorchidism. Although there is no specific treatment for these conditions, pediatricians should focus on referring patients to various specialists in order to treat each individual manifestation.

• Korean Journal of Metals and Materials
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• v.48 no.1
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• pp.57-61
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• 2010

Nanosized surface structures of Cu powders were investigated at the atomic scale by field-emission transmission electron microscope techniques. The nanoscale surface oxide layer on the Cu powder was analyzed to be the $CU_2O$ phase by electron diffraction pattern and electron energy-loss spectroscopy. In addition, it was found from high-resolution transmission electron microscopy study that there are formed no surface oxide layers on the surface of alkanethiol coated Cu powders.

• Journal of Digestive Cancer Research
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• v.4 no.2
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• pp.113-121
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• 2016

Background: We evaluated technique of hepatic resections using suprahilar-extrafascial dissection of Glissonean pedicle with vascular stapling device for pedicle transection with intent to minimize operative time and blood loss. Methods: We analyzed the clinical records of 326 patients who underwent anatomic liver resection by suprahilar-extrafascial pedicle isolation with vascular stapling division technique. Results: The minor liver resections were associated with significantly shorter surgery duration (105.1±21.1 vs. 225.6±75.6) and transection time (40.1±14.5 vs. 96.3±55.2) than major hepatectomies (p<0.0001 for all). The mean blood loss was 350.8±100.5 mL in minor resection and 485.4±250.2 mL in major resection (p=0.001). The mean blood transfusion requirement was 400.8±109.5 mL for minor resections and 550.9±100.0 mL for major hepatectomy (p=0.072). There was no significant difference in morbidity and mortality between groups (p=0.980; p=0.945). Major as well as minor liver resection were oncology superior with no significant difference in the 5-year overall survival rates. Conclusion: Suprahilar-extrafascial dissection of Glissonean pedicle represents an effective and safe technique of liver resection. Presented approach allows early and easy ischemic delineation of appropriate liver territory to be removed with selective inflow vascular control. It is not time consuming and it is very useful in re-resection, as well as oncological reasonable.

• Journal of Preventive Medicine and Public Health
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• v.28 no.3 s.51
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• pp.651-662
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• 1995

In Korea there is no specific method of age adjustment in noise induced hearing loss(NIHL). We attempted the age adjustment to understand the effects of age on the diagnosis of NIHL. We used the International Standard Organization 1999 as an age adjustment method. We used the 1, 617 otologically normal person's hearing data from a health examination center, and 206 workers diagnosed as NIHL. We concluded as follows; 1. The ISO 7029 function used for age specific hearing loss is not suited to Korean people. 2. The mean of age specific hearing loss is 11.0 6.2dB and the older of age, the more decrease on hearing loss, especially in 4000Hz. 3. The difference of NIHL between before age adjustment and after age adjustment in the 3rd decade is 5.4dB, in the 4th decade is 6.7dB, in the 5th decade is 8.5dB, in the 6th decade is 10.4dB, and in the 7th decade is 12.9dB. The older, the more is the difference. 4. After age adjustment, the number of workers diagnosed as NIHL decreases to 60% of unadjusted.

• Tribology and Lubricants
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• v.21 no.6
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• pp.249-255
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• 2005

In this paper, the friction characteristic of engine bearings has been analyzed in terms of a friction loss power, a minimum film thickness and an oil film pressure. This analysis has been focused on the fuel economy improvement with a low viscosity engine oil such as SAE 0W-40, which is used for a friction loss reduction and increased for a Diesel fuel economy. The friction loss power, the minimum oil film thickness and oil film pressure distribution for plain bearings of a Diesel engine are analyzed using an AVL's EXCITE program with a conventional engine oils of SAE 5W-40 and 10W-40, and a low viscosity engine oil of SAE 0W-40. The computed results indicate that a viscosity of engine oils is closely related to the friction loss power and the decreased minimum film thickness in which is a key parameter of a load carrying capacity of an oil film pressure distribution. When the low viscosity engine oil is supplied to engine bearings, it does not affect to the formation of a minimum oil film thickness. But the friction loss power has been significantly affected by low viscosity engine oil at a low operating temperature of 0. Based on the FEM computed results, the low viscosity engine oil at a low temperature range will be an important factor for an improvement of the fuel economy improvement.

• Archives of Plastic Surgery
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• v.42 no.5
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• pp.567-571
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• 2015

Background Bariatric surgeries performed in the USA has increased twelve-fold in the past two decades. The effects of rapid weight loss on facial features has not been previously studied. We hypothesized that bariatric surgery will mimic the effects of aging thus giving the patient an older and less attractive appearance. Methods Consecutive patients were enrolled from the bariatric surgical clinic at our institution. Pre and post weight loss photographs were taken and used to generate two surveys. The surveys were distributed through social media to assess the difference between the preoperative and postoperative facial photos, in terms of patients' perceived age and overall attractiveness. 102 respondents completed the first survey and 95 respondents completed the second survey. Results Of the 14 patients, five showed statistically significant change in perceived age (three more likely to be perceived older and two less likely to be perceived older). The patients were assessed to be more attractive postoperatively, which showed statistical significance. Conclusions Weight loss does affect facial aesthetics. Mild weight loss is perceived by survey respondents to give the appearance of a younger but less attractive patient, while substantial weight loss is perceived to give the appearance of an older but more attractive patient.