• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.85-90
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• 2017

The $TiCl_4$ as a blocking material is adsorbed in the mesoporous $TiO_2$ electron transfer layer(ETL) of the Perovskite solar cell to prevent the direct contact between the FTO electrode and the photoactive layer(AL), and facilitate the movement of the electrons between $TiO_2:TiCl_4$ ETL and Perovskite AL to improve the photoelectric conversion efficiency(PCE). The structure of the perovskite solar cell is FTO/$TiO_2:TiCl_4$/Perovskite($CH_3NH_3PbI_3$)/spiro-OMeTAD/Ag. It was investigated that the dipping time of the $TiO_2$ into $TiCl_4$ aqueous solution affects on the photoelectric characteristics of the device. By the dipping for 30 minutes, the PCE of the perovskite solar cell with the $TiO_2:TiCl_4$ ETL was the highest 10.46%, which is 27% higher than the cell with $TiO_2$ ETL. From SEM, EDS, and XRD characterization on the $TiO_2:TiCl_4$ ETL and the perovskite AL, it was measured that the decrease of the porosity of the $TiO_2$ layer, the detection of the Cl component by the $TiCl_4$ adsorption, the cube-type morphology of perovskite AL, and shift of the $PbI_2$ peak of the perovskite AL. From these results, it was confirmed that the $TiO_2:TiCl_4$ ETL and the perovskite AL were formed.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.201-208
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• 2006

Optical characteristics of InGaAs quantum dot (QD) laser structures with an Al native oxide (AlOx) layer as a current-blocking layer were studied by means of photoluminescence (PL), PL excitation, and spatially-resolved micro-PL techniques. The InGaAs QD samples were first grown by molecular-beam epitaxy (MBE), and then prepared by wet oxidation and thermal annealing techniques. For the InGaAs QD structures treated by the wet oxidation and thermal annealing processes, a broad PL emission due to the intermixing effect of the AlOx layer was observed at PL emission energy higher than that of the non-intermixed region. We observed a dominant InGaAs QD emission at about 1.1 eV in the non-oxide AlAs region, while InGaAs QD-related emissions at about 1.16 eV and $1.18{\sim}1.20eV$ were observed for the AlOx and the SiNx regions, respectively. We conclude that the intermixing effect of the InGaAs QD region under an AlOx layer is stronger than that of the InGaAs QD region under a non-oxided AlAs layer.

• The Journal of Korean Society for Radiation Therapy
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• v.8 no.1
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• pp.41-54
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• 1996

The secondary electrons developed by interaction between primary beam and a tray mounted for blocks in Megavoltage irradiation result in excess soft radiation dose to the surface layer. To reduce this electron contamination, electron filters have been used to be attached under a tray. Various filters with Cu and Al plates in six different thickness and Cu/Al combined plates in 3 different thickness were tested to measure the reduction rate of secondary electron contamination to the surface layer. The measurement to find optimal filter was performed on 6MV linear accelerator in $10 cm{\times}10 cm$ field size and fixed 78.5cm source to measurement points distance from surface to maximum build up point in 2mm intervals. The result was analyzed as the ratio of measured doses with using filters, to standard doses of measured open beam. The result of this study was fellowing : 1. The contaminated low energy radiation were mainly produced by blocking tray. 2. The surface absorbed dose was slowly increased by increasing irradiation field size but rapidly increased at field size above $15cm{\times}15cm$. 3. Al plate upto 2.5mm thickness used as a filter was found to be inadequate due to the failure of reduction of the surface absorbed dose below doses of the under surface upto the maximal build up. Cu 0.5mm plate and Cu 0.28mm/A1 1.5mm compound plate were found to be optimal filters. 4. By using these 2 filters, the absorbed dose to the surface were effectively reduced $5.5\%$ in field size $4cm{\times}4cm,\;11.3\%$ in field size $10cm{\times}10cm,\;22.3\%$ in field size $25cm{\times}25cm$. 5. In field size $10cm{\times}10cm$, the absorbed dose to the surface of irradiation was reduced by setting TSD 20cm at least,. but effective and enough dose reduction could be achieved by setting TSD 30cm as 2 optimal filters used. 6. More surface dose absorbed at TSD less than 7.4cm with a tray and filters together indicated that soft radiation was also developed by filters. 7. The variation of PDD by the different size of irradiation field was minimal as 2 optimal filters used. There was also not different in variation of PDD according to using any of two different filters. 8. PDD was not effected either by various TSD or by using the different filter among two.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.150-154
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• 1990

Various sterilization temperatures $(110^{\circ}C,\;120^{\circ}C,\;130^{\circ}C)$ and air volumes (air, 31ml, half-vacuum; 13ml, vacuum; -0.7ml) within the retort pouch were tested for the development of the simple retort rice processing techniques in which the pouch were filled with rice and water, and then sterilized. Water content of retort rice was found to be 59.0-63.3% resulting from mixing the rice and water in the ratio of 1:1.1. The most uniform water content was obtained from retort rice sterilized at $130^{\circ}C$ and packaged under vacuum. The larger water content differences were observed with the increase in internal air volumes within the retort pouch. Spreading degree of retort rice was geater than that of general cooked rice, was lower in upper layer than in low layer, and became lower with the larger air volume and higher sterilization temperature. a degree of rice became higher with the Increase of sterilization temperature but that was not affected by the internal air volume of the pouch. The higher sterilization temperature and the lower the air volume, the higher the whiteness was. The highest whiteness was obtained by packaging under vacuum and sterilizing at $130^{\circ}C$. Intact degree was much higer in packaging under air than vacuum. In sensory evaluation the retort rice of vacuum pack was good in color and spreading degree but not in appearance because of blocking and deforming, but that of air pack was good in texture on the contrary. The best quality was obtained by packaging under half-vacuum and sterilizing at $130^{\circ}C$.

• Journal of Oral Medicine and Pain
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• v.24 no.2
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• pp.145-161
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• 1999

The proto-oncogene bcl-2 confers a survival advantage to cells by blocking programmed cell death (apoptosis). Overexpression of bcl-2 probably plays a role in tumorigenesis, and the expression of the bcl-2 protein has been investigated in many kinds of tumors. An increased expression of nitric oxide synthetase(NOS) has been observed in human colon cancer cell lines as well as in human gynecological, breast, and CNS tumors. However there have been only a few reports on the expression of bcl-2 and $NOS_2$ in oral white lesions and cancer. The aim of this study was to investigate the relationship between the expression of Bcl-2 and $NOS_2$ and several pathological parameters such as histological types and layers. We reported desregulation of bcl-2 and $NOS_2$ expression during progression from oral white lesion, lichen planus and leukoplakia to squamous cell carcinoma. The obtained results were as follows: 1. Immunohistochemical analysis with monoclonal antibodies to bcl-2 oncoprotein and $NOS_2$ in formalin-fixed paraffin-embedded tissue sections revealed that bcl-2 expression is restricted to the basal cell layer and $NOS_2$ was mild expressed only in subepithelial inflammatory cells in normal human mucosa. There wasn't specific finding of those in lichen planus and leukoplakia. 2. Bcl-2 immunoreactivity in severe epithelial dysplasia or CIS occurs throughout the epithelium, $NOS_2$ reactivity in most superficial layer were noted. 3. In well-differentiated squamous cell carcinomas, mostly bcl-2 was overexpressed. In moderated and poor squamous cell carcinomas, the expression of $NOS_2$ was increased and that of bcl-2 was decreased. 4. The immunoreactivity of bcl-2 was 12.5% of normal mucosa, 30% of leukoplakia, 44% of lichen planus and 67% of carcinoma in situ. In carcinoma, those were 43%, 50% and 67% according to differentiation, respectively. 5. The immunoreactivity of $NOS_2$ was 25% of normal mucosa, 70% of leukoplakia, 78% of lichen planus and 100% of carcinoma in situ and epithelial dysplasia. In carcinoma, those were higher in moderated(100%) and poor(83%) squamous cell carcinomas than in well differentiated type(71%). 6. The expression of bcl-2 and $NOS_2$ by Western blot was increased highly in lichen planus and leukoplakia. Therefore, the expression of bcl-2 was increased in the white and precancerous lesions and that was decreased by differentiation of carcinoma. However, $NOS_2$ immunoreactivity in carcinoma in situ was lower than those in moderated and poor squamous cell. These findings suggest that the interaction of bcl-2 and $NOS_2$ may be roled importantly in growth and development of carcinoma.

• Economic and Environmental Geology
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• v.41 no.3
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• pp.327-334
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• 2008

Understanding the chemical characteristics of sediments and the nutrient diffusion from sediments to the water body is important in the management of surface water quality. Changes in chemical properties and nutrient concentration of a submerged soil were monitored for 6 months using a microcosm with the thickness of 30cm for upland soil and 15cm of water thickness above the soil. The soil color changed from yellowish red to grey and an oxygenated layer was formed on the soil surface after 5 week flooding. The redox potential and the pH of the pore water in the microcosm decreased during the flooding. The nitrate concentration of the surface water was continuously increased up to $8\;mg\;l^{-1}$ but its phosphate concentration decreased from $2\;mg\;l^{-1}$ to $0.1\;mg\;l^{-1}$ during flooding. However, the concentrations of $NH_4^+$, $PO_4^{3-}$, Fe and Mn in the pore water were increased by the flooding during this period. The increased $NO_3^-$ in the surface water was due to the migration of $NH_4^+$ formed in the soil column and the oxidation to $NO_3^-$ in the surface water. The increased phosphate concentration in the pore water was due to the reductive dissolution of Fe-oxide and Mn-oxide, which scavenged phosphate from the soil solution. The oxygenated layer played a role blocking the migration of phosphate from the pore water to the water body.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.477-477
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• 2008

For more than three decades, the gate dielectrics in CMOS devices are $SiO_2$ because of its blocking properties of current in insulated gate FET channels. As the dimensions of feature size have been scaled down (width and the thickness is reduced down to 50 urn and 2 urn or less), gate leakage current is increased and reliability of $SiO_2$ is reduced. Many metal oxides such as $TiO_2$, $Ta_2O_4$, $SrTiO_3$, $Al_2O_3$, $HfO_2$ and $ZrO_2$ have been challenged for memory devices. These materials posses relatively high dielectric constant, but $HfO_2$ and $Al_2O_3$ did not provide sufficient advantages over $SiO_2$ or $Si_3N_4$ because of reaction with Si substrate. Recently, $HfO_2$ have been attracted attention because Hf forms the most stable oxide with the highest heat of formation. In addition, Hf can reduce the native oxide layer by creating $HfO_2$. However, new gate oxide candidates must satisfy a standard CMOS process. In order to fabricate high density memories with small feature size, the plasma etch process should be developed by well understanding and optimizing plasma behaviors. Therefore, it is necessary that the etch behavior of $HfO_2$ and plasma parameters are systematically investigated as functions of process parameters including gas mixing ratio, rf power, pressure and temperature to determine the mechanism of plasma induced damage. However, there is few studies on the the etch mechanism and the surface reactions in $BCl_3$ based plasma to etch $HfO_2$ thin films. In this work, the samples of $HfO_2$ were prepared on Si wafer with using atomic layer deposition. In our previous work, the maximum etch rate of $BCl_3$/Ar were obtained 20% $BCl_3$/ 80% Ar. Over 20% $BCl_3$ addition, the etch rate of $HfO_2$ decreased. The etching rate of $HfO_2$ and selectivity of $HfO_2$ to Si were investigated with using in inductively coupled plasma etching system (ICP) and $BCl_3/Cl_2$/Ar plasma. The change of volume densities of radical and atoms were monitored with using optical emission spectroscopy analysis (OES). The variations of components of etched surfaces for $HfO_2$ was investigated with using x-ray photo electron spectroscopy (XPS). In order to investigate the accumulation of etch by products during etch process, the exposed surface of $HfO_2$ in $BCl_3/Cl_2$/Ar plasma was compared with surface of as-doped $HfO_2$ and all the surfaces of samples were examined with field emission scanning electron microscopy and atomic force microscope (AFM).

• Journal of the Korean GEO-environmental Society
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• v.16 no.4
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• pp.13-22
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• 2015

The combined impact of Dissolved Organic Matter (DOM) fouling and inorganic ($CaSO_4,Ca_3(PO_4)_2$) scaling on the retention of TNT (2, 4, 6-Trinitrotoluene), RDX (Hexahydro-1, 3, 5-trinitro-1, 3, 5-triazine) and HMX (1, 3, 5, 7-Tetranitro-1, 3, 5, 7-tetrazocane) explosive contaminants by nano-filtration membrane were studied, since organic fouling and salt scaling are the major limitations for membrane filtration. Results reported here indicate that DOM fouling layer with a humic acid does not necessarily lead to an immediate loss of permeate flux but can result in a severe impact on the flux loss when both humic acid and inorganic scaltants were presented simultaneously. The $Ca_3(PO_4)_2$ mixed with humic acid showd most sever flux loss (42%) compared to that of only humic acid presence (8%). It could be a result that the scaling formation of the NF membrane was dominated by cake layer formation of DOM and it was along with pore blocking by the formation of crystals inside the porous active matrix of the NF membrane. In addition, these results indicated that the membrane selectivity of the explosives retention trended correlated with respect to increasing explosives size (listed by MW) based on greater steric interactions and followed the order (MW, g $mol^{-1}$; removal, %): HMX (296.15; 83%) ${\gg}$ RDX (222.12; 49%) ≋ TNT (227.13; 32%). Because the scaling and fouling layer could lead to a additional cake-enhanced concentration polarisation effect, the retention of explosives with the presence of humic acid in the feed solution and inorganic scaling formation on top of an organic fouling layer do not differ substantially retention from that of pure DI feed and NaCl solution.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.7
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• pp.37-43
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• 2008

In this paper, the dependence of electrical characteristics of Silicon-$Al_2O_3$-Nitride-Oxide-Silicon (SANOS) memory cell transistors and program/erase (P/E) speed, reliability of memory device on interface trap between Si substrate and tunneling oxide and bulk trap in nitride layer were investigated using charge pumping method which has advantage of simple and versatile technique. We analyzed different SANOS memory devices that were fabricated by the identical processing in a single lot except the deposition method of the charge trapping layer, nitride. In the case of P/E speed, it was shown that P/E speed is slower in the SANOS cell transistors with larger capture cross section and interface trap density by charge blocking effect, which is confirmed by simulation results. However, the data retention characteristics show much less dependence on interface trap. The data retention was deteriorated as increasing P/E cycling number but not coincides with interface trap increasing tendency. This result once again confirmed that interface trap independence on data retention. And the result on different program method shows that HCI program method more degraded by locally trapping. So, we know as a result of experiment that analysis the SANOS Flash memory characteristic using charge pumping method reflect the device performance related to interface and bulk trap.

• Journal of the Korean Magnetics Society
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• v.7 no.5
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• pp.265-273
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• 1997

The MR ratios and the exchange biasing field and interlayer coupling field were investigated in $Ni_{91}Fe_{19}/Co_{90}Fe_{10}/Cu/Co_{90}Fe_{10}/NiO$ spin-valve sandwiches grown on antiferromagnetic NiO films as a function of the NiO thickness, the thickness of Cu and pinning layer $Co_{90}Fe_{10}$. The spin-valve sandwiches were deposited on the Corning glass 7059 by means of the 3-gun dc and 1-gun rf magnetron sputtering at a 5 mtorrpartial Ar pressure and room temperature. The deposition field was 50 Oe. The MR curve was measured by the four-terminal method with applied magnetic soft bilayer [NiFe/CoFe] (90$\AA$) decreased dramatically to less than 10 Oe when the NiFe/CoFe bilayer used an NiFe bilayer thicker that 20$\AA$. So NiFe layer improved the softmagnetic properties in the NiFe/CoFe bilayer. The GMR ratio and the magnetic field sensitivity of the spin-valve film $Ni_{91}Fe_{19}(40{\AA})/Co_{90}Fe_{10}(50{\AA}) /Cu(30{\AA})/Co_{90}Fe_{10}(35{\AA})/NiO(800{\AA})$ was 6.3% and about 0.5 (%/Oe), respectively. The MR ratio had 5.3% below an annealing temperature of 20$0^{\circ}C$ which slowly decreased to 3% above 30$0^{\circ}C$. The large blocking temperature of the spin-valve film was taken (as being) due to the good stability of the NiO films. Thus, the spin-valve films with a free NiFe/CoFe layer clearly had a high large GMR output and showed a effective magnetic field sensitivity for a suitable spin-valve head material.