• Membrane Journal
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• v.33 no.5
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• pp.248-256
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• 2023

Indium tin oxide (ITO) transparent electrode film has been widely adopted for the various applications such as display and electric vehicle. In this paper, we studied how to enhance the thermoforming stability of ITO film by applying the highly conductive Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin layer. Based on the change of sheet resistance value, the influence of the additional solvent with different boiling point was investigated for the PEDOT:PSS coating solution. In addition, by analyzing optical transmittance and Raman spectrum, we confirmed the key mechanism which determine the final electrical conductivity of the PEDOT:PSS on ITO film using an ethylene glycol solvent. The final ITO transparent electrode coated with PEDOT:PSS performed the outstanding endurance of electrical conduction even in 126% stretching condition.

• Membrane Journal
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• v.33 no.5
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• pp.257-268
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• 2023

Membrane capacitive deionization (MCDI) is a variation of the conventional CDI process that can improve desalination efficiency by employing an ion-exchange membrane (IEM) together with a porous carbon electrode. The IEM is a key component that greatly affects the performance of MCDI. In this study, we attempted to derive the optimal fabricating factors for IEMs that can significantly improve the desalination efficiency of MCDI. For this purpose, pore-filled IEMs (PFIEMs) were then fabricated by filling the pores of the PE porous support film with monomers and carrying out in-situ photopolymerization. As a result of the experiment, the prepared PFIEMs showed excellent electrochemical properties that can be applied to various desalination and energy conversion processes. In addition, through the correlation analysis between MCDI performance and membrane characteristic parameters, it was found that controlling the degree of crosslinking of the membranes and maximizing permselectivity within a sufficiently low level of membrane electrical resistance are the most desirable membrane fabricating condition for improving MCDI performance.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.1
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• pp.16-21
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• 2024

Using electrochromic devices (ECD), smart window films that can change the colors from tinted state into transparent state by applying an external voltage were manufactured. Polyethylene terephthalate (PET) film was used as a substrate instead of conventional glass, and ECD modules having a total thickness of about 50 ㎛ were manufactured by sequentially introducing an ITO/Ag/ITO electrode layer, a WO3/TIC2 organic discoloration layer, and a Nafion fluorine electrolyte layer. Through a series of sputtering, bar coating, and thermal compression processes, a large scale smart window with a horizontal and vertical length of more than 80 mm was manufactured. When DC 3.5 V was applied, the transmittance decreased from 54 % to 24 % and moreover the color change could be confirmed even with the naked eye. Reversible color change capability at low external voltage implies that external sunlight can be selectively blocked which is effective in terms of energy saving.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.2
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• pp.55-60
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• 2024

Two-dimensional (2D) RuO₂ nanosheets with nanometer thickness were synthesized using a chemical exfoliation method. The synthesized 2D-RuO₂ was hybridized with Ag-nanowire (NW), which is attracting attention as a next-generation transparent electrode material. After coating Ag-NW on the substrate, 2D-RuO₂ was subsequently coated on the Ag-NW. Although there was a decrease in optical transmittance, the hybridization of 2D-RuO₂ confirmed the effect of reducing sheet resistance. Furthermore, the flexibility of the fabricated transparent electrodes was also studied. It was confirmed by the change in sheet resistance after bending. The additional coating of 2D-RuO₂ improved the flexibility of the transparent electrodes.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.155-165
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• 2015

Well-feathered (over 10 feathers) 'Fuji'/M.9 apple trees were planted at $3.0{\times}1.0m$ and trained to slender spindle with 2.5 m height or to tall spindle with 3.5 m height, and the vegetative growth, productivity, and fruit quality of two training systems were compared for 8 years. The canopy volume of the tall spindle trees surpassed that of the slender spindle trees 4 years after planting and was 25% larger than that of the slender spindle trees 5 years after planting. The accumulated yield over 8 years for the tall spindle system was 14% higher than that of the slender spindle system. Alternate bearing and incidence of marssonina blotch were observed in both treatments after 5 years of planting. There was often vegetative imbalance in the trees however, the degree of yield loss and vegetative imbalance of the tall spindle trees was lower than those of the slender spindle trees. Soluble solid content and fruit red color of the tall spindle trees were higher than that of the slender spindle trees in 5 year after planting, resulting from increased light penetration in the canopy due to even distribution of lateral branches and from fruit bearing in different height locations of the trees. In conclusion, increasing the tree height to about 3.5 m using slender spindle 'Fuji'/M.9 apple trees planted with over 333 trees per 10a led to better light penetration, yield and fruit quality compared to a conventional wide training system with the slender spindle.

• Journal of Life Science
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• v.19 no.6
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• pp.770-780
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• 2009

A new photosensitizer, 9-Hydroxypheophorbide-a (9-HpbD-a), was derived from Spirulina platensis. We conducted a series of experiments, in vitro and in vivo, to evaluate the anticancer effect and mechanism of photodynamic therapy using 9-HpbD-a and 660 nm diode lasers on a squamous carcinoma cell line. We studied the cytotoxic effects of pheophytin-a, 9-HpbD-a, 9-HpbD-a red and 660 nm diode lasers in a human head and neck cancer cell line (SNU-1041). Cell growth inhibition was determined by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. The effects of 9-HpbD was higher than those of 9-HpbD-a red or pheophytin-a in PDT. We then tested the cytotoxic effects of 9-hydroxypheophorbide-a (9-HpbD-a) in vitro. The cultured SNU-I041 cells were treated with serial concentrations of 9-HpbD-a followed by various energy doses (0, 0.1, 0.5, 3.2 J/$cm^{2}$) and by various interval times (0, 3, 6, 9, 12 hr) until laser irradiation, then MTT assay was applied to measure the relative inhibitory effects of photodynamic therapy (PDT). Optimal laser irradiation time was 30 minutes and the cytotoxic effects according to incubation time after 9-HpbD-a treatment increased until 6 hours, after which it then showed no increase. To observe the cell death mechanism after PDT, SUN-I041 cells were stained by Hoechst 33342 and propidium iodide after PDT, and observed under transmission electron microscopy (TEM). The principal mechanism of PDT at a low dose of 9-HpbD-a was apoptosis, and at a high dose of 9-HpbD-a it was necrosis. PDT effects were also observed in a xenografted nude mouse model. Group I (no 9-HpbD-a, no laser irradiation) and Group II (9-HpbD-a injection only) showed no response (4/4, 100%), and Group III (laser irradiation only) showed recurrence (1/4,25%) or no response (3/4, 75 %). Group IV (9-HpbD-a + laser irradiation) showed complete response (10/16, 62.5%), recurrence (4/16, 25%) or no response (2/16, 12.5%). Group IV showed a significant remission rate compared to other groups (p<0.05). These results suggest that 9-HpbD-a is a promising photosensitizer for the future and that further studies on biodistribution, toxicity and mechanism of action would be needed to use 9-HpbD-a as a photosensitizer in the clinical setting.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.119-125
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• 1987

Optical properties of sea water were studied in the Sagami Bay, Japan, based on the data obtained from six oceanographic stations in June, 1985. The observation of surface irradiance and underwater irradiance of sea water for eight kind of wavelengths (378, 422, 481, 513, 570, 621, 653, 677 nm) of sun light was conducted using the underwater irradiameter $(Isigawa\;\#\;SR-8)$. The mean attenuation coefficient of the sea water was appeared to be 0.166 $(0.061\~0.644)$ and the attenuation coefficient of the sea water for wavelength appeared such as 0.121 for 378 nm, 0.105 for 422 nm, 0.097 for 481 nm, 0.099 for 513 nm, 0.138 for 570 nm, 0.253 for 621 nm, 0.258 for 653 nm, 0.253 for 677 nm. The transparency was 12.9 m $(7.2\~18m)$, water color was $(5\~10m)$ in the study area and the sun altitude was $70.79^{\circ}\;(57.44^{\circ}\~78.42^{\circ}C)$ The relationship between attenuation coefficient (K) ana transparency (D) was $K=2.87/D(1.06/D\~5.48/D)$. The rates of light penetration for eight kind of wavelenths (378, 422, 481, 513, 570, 621, 653, 677 nm) were computed with reference to the surface light intensity respectively, The mean rate of light penetration in proportion to depths were $77.93\%\;(52.52\~94.06\%)$ in 1 m layer, $35.46\%\;(4.00\~73.64\%)$ in 5m layer, $18.71\%\;(0.24\~54.23\%)$ in 10m layer and $7.00\%\;(0.007\~27.58\%)$in 20m layer. The rate of light penetration at the transparency layer with reference to the surface light intensity was shown as $13.02\%\;(0.42\~34.78\%)$.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.79-84
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• 2017

The solar cells should be protected from the moisture and oxygen in order to sustain the properties and reliability of the devices. In this research, we prepared the protection films on the flexible plastic substrates by spray coating method using organic-inorganic hybrid solutions. The protection characteristics were studied depending on the various process conditions (nozzle distance, thicknesses of the coatings, film structures). The organic-inorganic solutions for the protection film layer were synthesized by addition of $Al_2O_3$ ($P.S+Al_2O_3$) and $SiO_2$ ($P.S+SiO_2$) nano-powders into PVA (polyvinyl alcohol) and SA (sodium alginate) (P.S) organic solution. The optical transmittances of the protection film with the thicknesses of $5{\mu}m$ showed 91%. The optical transmittance decreased from 81.6% to 73.6% with the film thickness increased from $78{\mu}m$ to $178{\mu}m$. In addition, the protective films were prepared on the PEN (polyethylene naphthalate), PC (polycarbonate) single plastic substrates as well as the Acrylate film coated on PC substrate (Acrylate film/PC double layer), and $Al_2O_3$ film coated on PEN substrate ($Al_2O_3$ film/PEN double layer) using the $P.S+Al_2O_3$ organic-inorganic hybrid solutions. The optimum protection film structure was studied by means of the measurements of water vapor transmittance rate (WVTR) and surface morphology. The protective film on PEN/$Al_2O_3$ double layer substrate showed the best water protective property, indicating the WVTR value of $0.004gm/m^2-day$.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.28-37
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• 2017

Mineral trioxide aggregate have been used for many years as a pulp therapy material. The most widely used product, Proroot white $MTA^{(R)}$ has a major drawback that it causes tooth discoloration. This study assessed discoloration of crown when various MTA-based materials were placed in the coronal aspect of the root canal. Seventy-five single-rooted, unrestored premolar teeth were selected. The teeth were randomly assigned to four experimental groups, each of $Biodentine^{(R)}$, Proroot $wMTA^{(R)}$, $Endocem^{(R)}$, $RetroMTA^{(R)}$ and one negative control groups. Color measurements were utilized by the Commission International de I'Eclairage's L*a*b* system with spectrophotometer. The color was assessed eight times : initial, 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 16 weeks after the placement. Statistical analysis was performed using the 2-way repeated analysis of variance and Bonferroni's method with p < 0.05. Proroot $wMTA^{(R)}$ induced significant decreases in $L^*$ values during experiment period. Tooth samples from the $Endocem^{(R)}$ group presented indistinct grayish color changes. The $Biodentine^{(R)}$ and $RetroMTA^{(R)}$ showed color stability. Consequently, while Proroot $wMTA^{(R)}$ and $Endocem^{(R)}$ that contain bismuth oxide as a radiopacifier showed tooth discoloration, displayed no sign of discoloration $Biodentine^{(R)}$ and $RetroMTA^{(R)}$ that contain zirconium oxide as a radiopacifier.

• Korean Journal of Medicinal Crop Science
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• v.12 no.4
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• pp.328-341
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• 2004

Presowing seed treatments used to enhance the rates of germination and afterward seedling emergence have not occasionally shown the same rate in indoor and field. The treatments considering germination mechanism and factors affecting germination must be totally included in indoor experiments so that the results drawn can be reproduced in the field. Seed germination is controlled by Phytochrome-mediated action changed with composition rates of red and far-red lights. Sunlight can penetrate soil into $6{\sim}9\;mm$ depth, which in turn means that seeds having $2{\sim}3\;mm$ in their width may receive the light if soil was covered 3 times over them. The penetrating light, moreover, turns to more far-red light than red light reverse to the sunlight. For germination tests after the artificial presowing seed treatments, therefore, seeds of smaller than 2 mm (< 2 mm), $2{\sim}3\;mm$, and larger than 3 mm (> 3 mm) must be done with incandescent lamp (IL) having more far-red light, with IL or in darkness, and in darkness, respectively. The 96 papers published in 13 Korean scientific journals up to the end of 2003 were analysed on the basis of the above explanation. 91 species were used 147 times as experimental materials; 101 times for < 2 mm seeds, 24 times for $2{\sim}3\;mm$ seeds and 22 times for > 3 mm seeds. If they were analysed as the light sources used for germination tests, correct applications reached more and less than 60% in both $2{\sim}3\;mm$ and > 3 mm seeds but 23% in < 2 mm seeds, conclusionally meaning that when the experimental results in the scientific papers were applied into farming practices, care was taken of their application because most of medicinal plant seeds were very small.