• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.288-290
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• 1997

Pulsed laser ablation has been used to fabricate superconducting $YBa_2Cu_3O_{7-x}$(YBCO) thin films on MgO substrates. The epitaxial YBCO thin films were grown at $750^{\circ}C$ and oxygen partial pressure of 200 mTorr. The electrical property and the characteristics of the YBCO thin films have been studied by R-T measurement. scanning electron microscopy (SEM) and X-ray diffraction (XRD). A microstrip line resonator has been fabricated using YBCO superconducting thin films by photolithography and wet-etch process. The resonator has linear microstrip line separated by a gap of 0.278 mm. We observed a fundamental resonance peak at the frequency of 10.007 GHz.

• Journal of Chest Surgery
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• v.16 no.4
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• pp.539-546
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• 1983

Maximal expiratory flow-volume [MEFV] curves were studied in 22 patients who underwent pneumonectomy with various pulmonary lesions, such as lung cancer, bronchiectasis and tuberculosis etc, at the preoperative stage and 3 week, 4 month and 12 month after pneumonectomy for the analysis of the reduction and progressive improvement of postoperative ventilatory function. And the factors affecting them like as age difference and the site of pneumonectomy were also analyzed. From these curves peak flow rate [PF R], maximal expiratory flows at 25% and 50% of expired forced vital capacity [V25, V50] and forced vital capacity [FVC] were obtained. In addition, partial pressure of oxygen and carbon dioxide in arterial blood were measured. The results were as follows; 1. The mixed type, especially obstructive type of ventilatory impairment was observed at 3 week after operation. For 1 year of postpneumonectomy FVC was increased by 12.3% of predicted compared to 2.6% of predicted V50. 2. The improvement of FVC during 1 year of postpneumonectomy showed decreasing tendency with the increase of age but the changes of V25 and V50 were unremarkable. 3. The differences of immediate postoperative reduction and progressive improvement of ventilatory capacity after right and left pneumonectomy were analyzed. The reduction of V50, V25 and FVC at 3 week of postoperation were greater in patients with right pneumonectomy [20.9%, 18.2% and 26.2% of predicted] than in patients with left pneumonectomy 16.5%, 18.2% and 18.1%]. But there was no significant difference of these values at 12 month after pneumonectomy. 4. The partial pressure of oxygen in arterial blood [$PaO_2$] was decreased by 13.6 mmHg at 3 week after pneumonectomy compared to the preoperative stage but returned to the normal range within 4 month after pneumonectomy. However, TEX>$PaCO_2$ was within the normal range during 1 year of postoperation.

• Journal of the Korean Chemical Society
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• v.31 no.3
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• pp.215-224
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• 1987

The electrical conductuctivity measurements have been made on polycrystalline samples of various compositions in the $MgO-TiO_2$ system from 600 to $1100^{\circ}C$ under $Po_2$'s of $10^{-8}\;to\;10^{-1}$atm. Plots of log ${\sigma}$ vs. 1/T at constant $Po_2$ are found to be linear with the inflections, and the activation energies are 1.94eV for the intrinsic range and 0.48eV for the extrinsic range, respectively. The log ${\sigma}$ vs. log $Po_2$ curves are found to be linear at constant temperature, and the conductivity dependences of $Po_2$ are closely approximated by ${\sigma}\;{\alpha}\;Po_2^{-1/6}$ for the extrinsic and ${\sigma}\;{\alpha}\;Po_2^{-1/4}$ for the intrinsic range, respectively. The dominant defects in this system are believed to be oxygen vacancy for the extrinsic and $Ti^{3-}$ interstitial for the intrinsic range. The conduction mechanisms in both the extrinsic and the intrinsic ranges are proposed by the results of the electrical conductivity dependence on the oxygen partial pressure. Polaron model was suggested in the extrinsic region by the conductivity dependences of temperature and $Po_2$.

• Journal of Veterinary Clinics
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• v.33 no.4
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• pp.237-242
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• 2016

A 1.86 kg, 3-year-old, female, Maltese was presented to the Veterinary Medical Teaching Hospital of Seoul National University after being hit by a car. The patient was diagnosed with urinary bladder rupture, diaphragmatic hernia and fracture of ilium, tibia and fibula. Repair surgery was performed after stabilizing treatment. During the surgery, hypoxia was identified and it worsened after positive pressure ventilation (partial pressure of oxygen in arterial blood ($PaO_2$): 52 mmHg, pulse oximetry ($SpO_2$): 87%, arterial hemoglobin oxygen saturation ($SpO_2$): 85.8%). In addition to hypoxia, blood pressure decreased to 30 mmHg. Positive pressure ventilation was discontinued because hypoxia and hypotension were aggravated. After suturing the diaphragm, air was withdrawn to form negative pressure within the thorax. However, negative pressure was not attained despite continuous withdrawal of air. A thoracostomy tube was placed because tension pneumothorax was strongly suspected. The patient recovered through close monitoring with the tube for 3 days. Due to limitation of evaluation of the lung, predicting occurrence of tension pneumothorax is difficult in patient of diaphragmatic hernia. Therefore, it is recommended that indicators of tension pneumothorax should be closely monitored during diagnosis and repair procedures of diaphragmatic hernia.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.625-629
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• 1991

The electrical conductivity of the Niobium Oxide-Lead Oxide systems containing 2.5, 5.0, 7.5, and 10.0 mol% of Lead Oxide has been measured in a temperature range 700${\sim}$$1100^{\circ}C$ under oxygen partial pressure of 2.0 ${\times}$ $10^{-1}$${\sim}$1.0 ${\times}$ $10^{-5}$ atm. The electrical conductivities of the system decreased with increasing PbO mol% and varied from $10^{-5}$ to $10^{-1}$ $ohm^{-1}$ $cm^{-1}$. The activation energy for conductivity was about 1.70 eV. The oxygen pressure dependence of electrical conductivity revealed that the system was a mixed conductor between ionic and electronic conductivities at high oxygen pressures and a n-type electronic conductivity with oxygen pressure dependence of -1/4 order at low oxygen pressures. The defect structure and electrical conduction mechanism of the system have been discussed with the data obtained.

• Progress in Superconductivity and Cryogenics
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• v.6 no.3
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• pp.27-32
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• 2004

High temperature superconducting coated conductor has a structure of /< superconducting layer>//. The buffer layer consists of multi layer, and the architecture most widely used in RABiTS approach is CeO$_2$(cap layer)/YSZ(diffusion barrier layer)/CeO$_2$(seed layer). Evaporation technique is used for the CeO$_2$ layer and DC reactive sputtering technique is used for the YSZ layer, A chamber was set up specially for DC reactive sputtering, Detailed features are as following. A separator divided the chamber into two halves a sputtering chamber and a reaction chamber. The argon gas for sputtering target elements flows out of the cap of sputtering gun, and water vapor for reaction with depositing species spouts near the substrate. Turbo pump is connected with reaction chamber. High speed deposition of YSZ film could be achieved in the chamber. Detailed deposition conditions (temperature and partial pressure of reaction gas) were investigated for the rapid growth of high quality YSZ film.

• Transactions on Electrical and Electronic Materials
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• v.15 no.4
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• pp.189-192
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• 2014

Yttria-stablized zirconia (YSZ) is the most commonly used electrolyte material, but the reduction in working temperature leads to insufficient ionic conductivity. Ceria based electrolytes (GDC) are more attractive in terms of conductivity at low temperature, but these materials are well known to be reducible at very low oxygen partial pressure. The reduction of electrolyte resistivity is necessary to overcome cell performance losses. So, thin YSZ/GDC bilayer technology seems suitable for decreasing the electrolyte resistance at lower operating temperatures. Bilayer electrolytes composed of a galdolinium-doped $CeO_2$ ($Ce_{0.9}Gd_{0.1}O_{1.95}$, GDC) layer and yttria-stabilized $ZrO_2$ (YSZ) layer with various thicknesses were deposited by RF sputtering and E-beam evaporation. The bilayer electrolytes were deposited between porous Ni-GDC anode and LSM cathode for anode-supported single cells. Thin film structure and surface morphology were investigated by X-ray diffraction (XRD), using $CuK{\alpha}$-radiation in the range of 2ce morphol$^{\circ}C$. The XRD patterns exhibit a well-formed cubic fluorite structure, and sharp lines of XRD peaks can be observed, which indicate a single solid solution. The morphology and size of the prepared particles were investigated by field-emission scanning electron microscopy (FE-SEM). The performance of the cells was evaluated over $500{\sim}800^{\circ}C$, using humidified hydrogen as fuel, and air as oxidant.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.11
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• pp.1329-1334
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• 1988

A new method was developed for growing oxidation film by thermal reaction of $NH_3$ and $O_2$. The growth rate increased with the increase of partial pressure of $NH_3$. Optical transparency of the growth film was 12% at the wave number 1100 $cm^{-1}$ compared with 17% by thermal dry oxidation method, and the quality was much better. In C-V characteristic curve, $Q_{OX}$ was almost equal to $Q_{SS}$ and no hysteresis phenomena was observed. n-MOS transistors fabricated with this new method showed $I_D$-$V_{DS}$ characteristics better than thermal dry oxidation method.

• Journal of the Korean Ceramic Society
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• v.28 no.9
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• pp.689-695
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• 1991

Dielectric properties of Ba1-$\chi$Sr$\chi$Ti1-yCayO3-y ceramics, where Sr and Ca were doped to Ba-site and Ti-site within the range of 0 x 0.24 and 0 y 0.05, respectively, were investigated. The substitution of Ca for Ti, which maintained the high resistivity of these formulations after sintering in a reducing atmosphere, was confirmed. Ca addition decreased the tetragonality c/a, increased the unit cell volume, and lowered Curie temperature, which were attributed to the occupancy of Ca2+ ions on Ti-sites. The lowering of Curie temperature by Ca addition was affected by the substitution of Sr for Ba-site; within 2 mol% of Ca, Curie temperature was lowered at a rate of 2$0^{\circ}C$ and 16$^{\circ}C$ per mol% of Ca at x=0 and x=0.08, respectively. Whereas the resistivity of the formulations without Ca was reduced to 107 {{{{ OMEGA }}cm, when sintered at low oxygen partial pressure of 10-9 MPa, the resistivity value higher than 1011 {{{{ OMEGA }}cm was maintained for the formulations containing Ca more than 0.5 mol%. Dielectric loss factor, tan$\delta$, was about 1% for most formulations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.783-786
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• 2003

Thin films of vanadium oxide(VOx) have been deposited by r.f. magnetron sputtering from $V_2O_5$ target in gas mixture of argon and oxygen. The oxygen/(oxygen+argon) partial pressure ratio of 0% and 8% is adopted. Crystal structure and optical properties of films sputter-deposited under different oxygen gas pressures and in situ annealed in vacuum at $400^{\circ}C$ for 1h and 4h are characterized through XRD and optical absorption measurements. The films as-deposited are amorphous, but $0%O_2$ films annealed for time longer than 4h and $8%O_2$ films annealed for time longer than 1h are polycrystalline. The optical transmission of the films annealed in vacuum decreases considerably than the as-deposited films and the optical absorption of all the films increases rapidly at wavelength shorter than about 550nm. Indirect and direct optical band gaps were decreased with increasing the annealing time.