• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.3
• /
• pp.124-127
• /
• 2005

It is demonstrated that the annealing process for Ti in-diffusion to z-cut $LiNbO_3$ at temperature lower than the curie temperature in a platinum (Pt) box can cause a ferroelectric micro-domain inversion at the +z surface and Li out-diffusion, therefore which should be avoided or suppressed for waveguide type periodically poled lithium niobate (PPLN) devices. The depth of the inversion layer depends on the Ti-diffusion conditions such as temperature, atmosphere, the sealing method of $LiNbO_3$ in the Pt box and crystal orientation is experimentally examined. The result shows that the polarization-inverted domain boundary appears at the only +z surface and its thickness is about $1.6{\mu}m$. Also, for the etched $LiNbO_3$, surface the domain shape was observed by the optical microscope and atomic force microscopy (AEM), and distribution of the cation concentrations in the $LiNbO_3$ crystal by the secondary ion mass spectrometry (SIMS).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.66-66
• /
• 2008

Most of the properties of ITO films depend on their substrate nature, deposition techniques and ITO film composition. For the display panel application, it is normally deposited on the glass substrate which has high strain point (>575 degree) and must be deposited at a temperature higher than $250^{\circ}C$ and then annealed at a temperature higher than $300^{\circ}C$ in order to high optical transmittance in the visible region, low reactivity and chemical duration. But the high strain point glass (HSPG) used as FPDs is blocking popularization of large sizes FPDs because it is more expensive than a soda lime glass (SLG). If the SLG could be used as substrate for FPDs, then diffusion of Na ion from the substrate occurs into the ITO films during annealing or heat treatment on manufacturing process and it affects the properties. Therefore proper care should be followed to minimize Na ion diffusion. In this study, we investigate the electrical, optical and structural properties of ITO films deposited on the SLG and the Asahi glass(PD200) substrate by rf magnetron sputtering using a ceramic target ($In_2O_3:SnO_2$, 90:10wt.%). These films were annealed in $N_2$ and air atmosphere at $400^{\circ}C$ for 20min, 1hr, and 2hrs. ITO films deposited on the SLG show a high electrical resistivity and structural defect as compared with those deposited on the PD200 due to the Na ion from the SLG on diffuse to the ITO film by annealing. However these properties can be improved by introducing a barrier layer of $SiO_2$ or $Al_2O_3$ between ITO film and the SLG substrate. The characteristics of films were examined by the 4-point probe, FE-SEM, UV-VIS spectrometer, and X-ray diffraction. SIMS analysis confirmed that barrier layer inhibited Na ion diffusion from the SLG.

• Korean Chemical Engineering Research
• /
• v.57 no.5
• /
• pp.679-686
• /
• 2019

Characteristics of adsorption equilibrium, kinetic and thermodynamic of aniline blue onto activated carbon from aqueous solution were investigated as function of initial concentration, contact time and temperature. Adsorption isotherm of aniline blue was analyzed by Langmuir, Freundlich, Redlich-Peterson, Temkin and Dubinin-Radushkevich models. Langmuir isotherm model fit better with isothermal data than other isotherm models. Estmated Langmuir separation factors ($R_L=0.036{\sim}0.068$) indicated that adsorption process of aniline blue by activated carbon could be an effective treatment method. Adsorption kinetic data were fitted to pseudo first order model, pseudo second order model and intraparticle diffusion models. The kinetic results showed that the adsorption of aniline blue onto activated carbon well followed pseudo second-order model. Adsorption mechanism was evaluated in two steps, film diffusion and intraparticle diffusion, by intraparticle diffusion model. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy for adsorption process were estimated. Enthalpy change (48.49 kJ/mol) indicated that this adsorption process was physical adsorption and endothermic. Since Gibbs free energy decreased with increasing temperature, the adsorption reaction became more spontaneously with increasing temperature. The isosteric heat of adsorption indicated that there is interaction between the adsorbent and the adsorbate because the energy heterogeneity of the adsorbent surface.

• Journal of radiological science and technology
• /
• v.32 no.3
• /
• pp.313-323
• /
• 2009

Diffusion-weighted imaging (DWI) has been demonstrated to be a practical method for the diagnosis of various brain diseases such as acute infarction, brain tumor, and white matter disease. In this study, we used two techniques to examine the average signal intensity (SI) and apparent diffusion coefficient (ADC) of the brains of patients who ranged in age from 10 to 60 years. Our results indicated that the average SI was the highest in amygdala (as derived from DWI), whereas that in the cerebrospinal fluid was the lowest. The average ADC was the highest in the cerebrospinal fluid, whereas the lowest measurement was derived from the pons. The average SI and ADC were higher in $T_2^*$-DW-EPI than in FLAIR-DW-EPI. The higher the b-value, the smaller the average difference in both imaging techniques; the lower the b-value, the greater the average difference. Also, comparative analysis of the brains of patients who had experienced cerebral infarction showed no distinct lesion in the general MR image over time. However, there was a high SI in apparent weighted images. Analysis of other brain diseases (e.g., bleeding, acute, subacute, chronic infarction) indicated SI variance in accordance with characteristics of the two techniques. The higher the SI, the lower the ADC. Taken together, the value of SI and ADC in accordance with frequently occurring areas and various brain disease varies based on the b-value and imaging technique. Because they provide additional useful information in the diagnosis and treatment of patients with various brain diseases through signal recognition, the proper imaging technique and b-value are important for the detection and interpretation of subacute stroke and other brain diseases.

• Journal of The Korean Dental Society of Anesthesiology
• /
• v.2 no.1 s.2
• /
• pp.1-6
• /
• 2002

The usage of nitrous oxide is increased for the anxious patient to dental treatment. There are two methods to induce the sedation during dental treatment. One is sedation with drugs the other no need of drugs. We discussed here about sedation with drugs. The methods of drug administration are oral, intramuscular, intravenous, inhalation. The method of oral administration of drugs are convenient to patient and doctor but poor controllability. Intramuscular method is a parenteral technique that maintains several advantages over the enteral technique. However its pales in comparison to other parenteral technique. Intravenous method represents most effective method of ensuring predictable and adequate sedation in all patients. But it has inability to reverse the action of drugs after they have been injected except some drugs (e.g., narcotics and benzodiazepine). A variety of gaseous agents may be administered by inhalation to produce sedation. In dental practice, the inhalation administration of gas means use of nitrous oxide. There are many advantages of nitrous oxide administration. First, very short latent period and rapid onset of drug action which lead to possible titration of drug concentration. With nitrous oxide, clinical effects may become noticeable as quickly as 15 to 30 seconds after inhalation. Recovery from inhalation sedation is also quite rapid. In out patient dental practice rapid recovery is very important because it permit to discharge the patient without escort and the patient return to their ordinary life without limit. To success the conscious sedation with nitrous oxide, the administrator should be keep the mind that always titration of nitrous oxide concentration during induction and treatment. Careful observation need during treatment to prevent oversedation because the adequate nitrous oxide concentration to patients changed by environmental stress. Always begins with 100% oxygen and ends with 100% oxygen to prevent diffusion hypoxia which rare in clinical practice.

• Journal of the Korean Electrochemical Society
• /
• v.18 no.3
• /
• pp.130-135
• /
• 2015

The rate capability and low-temperature characteristics of graphite electrode are investigated after surface treatment with copper phthalocyanine (CuPc) or phthalocyanine (Pc). Uniform coating layers comprising amorphous carbon or copper are generated after the treatment. The rate performance of graphite electrodes is enhanced by the surface treatment, which is more prominent with CuPc. The resistance of the graphite electrode estimated from electrochemical impedance spectroscopy and pulse resistance measurement is the smallest for the CuPc-treated graphite. It is likely that the amorphous carbon layer formed by the decomposition of Pc facilitates $Li^+$ diffusion and the metallic copper derived from CuPc improves the electrical conductivity of the graphite electrode.

• Electrical & Electronic Materials
• /
• v.8 no.5
• /
• pp.619-625
• /
• 1995

Polycrystalline CdTe thin film has been studied for photovoltaic application due to the 1.45 eV band gap energy ideal for solar energy conversion and high absorption coefficient. The formation of low resistance contact to p-CdTe is difficult because of large work function(>5.5eV). Common methods for ohmic contact to p-CdTe are to form a p+ region under the contact by in-diffusion of contact material to reduce the barrier height and modify a p-CdTe surface layer using chemical treatment. In this study, the surface chemical treatment of p CdTe was carried out by H$\_$3/PO$\_$4/+HNO$\_$3/ or K$\_$2/Cr$\_$2/O$\_$7/+H$\_$2/SO$\_$4/ solution to provide a Te-rich surface. And various thin film contact materials such as Cu, Au, and Cu/Au were deposited by E-beam evaporation to form ohmic contact to p-CdTe. After the metallization, post annealing was performed by oven heat treatment at 150.deg. C or by RTA(Rapid Thermal Annealing) at 250-350.deg. C. Surface chemical treatments of p-CdTe thin film improved metal/p-CdTe interface properties and post heat treatment resulted in low contact resistivity to p-CdTe.Of the various contact metal, Cu/Au and Cu show low contact resistance after oven and RTA post-heat treatments, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.33 no.6
• /
• pp.454-459
• /
• 2020

In this study, a TiO₂/TiO_2-x-based resistance variable memory was fabricated using a DC/RF magnetron sputtering system and ALD. In order to analyze the effect of oxygen plasma treatment on the performance of resistance random access memory (ReRAM), the TiO₂/TiO_2-x-based ReRAM was evaluated by applying RF power to the TiO_2-x oxygen-holding layer at 30, 60, 90, 120, and 150 W, respectively. The ReRAM was fabricated, and the electrical and surface area performances were compared and analyzed. In the case of ReRAM without oxygen plasma treatment, the I-V curve had a hysteresis curve shape, but the width was very small, with a relatively high surface roughness of the oxygen-retaining layer. However, in the case of oxygen plasma treatment, the HRS/LRS ratio for the I-V curve improved as the applied RF power increased; stable improvement was also noted in the surface roughness of the oxygen-retaining layer. It was confirmed that the low voltage drive was not smooth due to charge trapping in the oxygen diffusion barrier layer owing to the high intensity ReRAM applied with an RF power of approximately 150 W.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1996.05a
• /
• pp.185-190
• /
• 1996

RFSP is a computer program to do fuel management calculations for CANDU reactors. Its main function is to calculate neutron flux and power distributions using two-energy-group, three dimensional neutron diffusion theory. However, up to now the treatment has not been true two-group but actually "one-and-half groups". In other words, the previous (1.5-group) version of RFSP lumps the fast fission term into the thermal fission term. This is based on the POWDERPUFS-V Westcott convention. Also, there is no up-scattering term or bundle power over cell flux (H1 factor) for the fast group. While POWDERPUFS-V provides only 1.5 group properties, true two-group cross sections for the design and analysis of CAUDU reactors can be obtained from WIMS-AECL. To treat the full two-group properties, the previous RFSP version was modified by adding the fast fission, up-scatter terms, and H1 factor. This two-group version of RFSP is a convenient tool to accept lattice properties from any advanced lattice code (e.g. WIMS-AECL DRAGON, HELIOS...) and to apply to advanced fuel cycles. In this study, the modification to implement the true two-group treatment was performed only in the subroutines of the ＊SIMULATE module of RFSP. This module is the appropriate one to modify first, since it is used for the tracking of reactor operating histories. The modified two-group RFSP was evaluated with true two-group cross sections from WIMS-AECL. Some tests were performed to verify the modified two-group RFSP and to evaluate the effects of fast fission and up-scatter for three core conditions and four cases corresponding to each condition. The comparisons show that the two-group results are quite reasonable and serve as a verification of the modifications made to RFSP. To assess the long-term impact of the full 2-group treatment, it is necessary to simulate a long period (several months) of reactor history. It will also be necessary to implement the full two-group treatment of reactivity devices and assess the reactivity-device worths.ce worths.

• Journal of Trauma and Injury
• /
• v.35 no.3
• /
• pp.209-214
• /
• 2022

We describe a case of hyperbaric oxygen therapy (HBOt) as an adjunct to treatment of a crush injury to the hand. A 34-year-old male paramedic was involved in a motor vehicle accident and admitted for diagnosis and surgical treatment. He sustained a crush injury to his right hand and presented with significant muscle damage, including multiple fractures and dislocations, an avulsion injury of the flexor tendons, and amputation of the distal phalanx of the little finger. He underwent reconstructive surgery and received HBOt over the following days. In the following 2 months, he lost the distal and middle phalanges of the little finger and recovered hand function. Posttraumatic compartment syndrome responds well to HBOt, which reduces edema and contributes to angiogenesis, as well as promoting the cascade of healing events. High-energy trauma causes massive cell destruction, and the blood supply is usually not sufficient to meet the oxygen demands of viable tissues. Hyperbaric oxygenation by diffusion through interstitial and cellular fluids increases tissue oxygenation to levels sufficient for the host's responses to injury to work and helps control the delayed inflammatory reaction. HBOt used as an adjunct to surgical treatment resulted in early healing and rehabilitation, accelerating functional recovery. The results suggest that adjunctive HBOt can be beneficial for the treatment of crush injuries of the hand, resulting in better functional outcomes and helping to avoid unnecessary amputations.