• Korean Journal of Materials Research
• /
• v.32 no.11
• /
• pp.481-488
• /
• 2022

The Cu₂ZnSn(S_xSe_1-x)₄ (CZTSSe) absorbers are promising thin film solar cells (TFSCs) materials, to replace existing Cu(In,Ga)Se₂ (CIGS) and CdTe photovoltaic technology. However, the best reported efficiency for a CZTSSe device, of 13.6 %, is still too low for commercial use. Recently, partially replacing the Zn²⁺ element with a Cd²⁺element has attracting attention as one of the promising strategies for improving the photovoltaic characteristics of the CZTSSe TFSCs. Cd²⁺ elements are known to improve the grain size of the CZTSSe absorber thin films and improve optoelectronic properties by suppressing potential defects, causing short-circuit current (J_sc) loss. In this study, the structural, compositional, and morphological characteristics of CZTSSe and CZCTSSe thin films were investigated using X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), and Field-emission scanning electron microscopy (FE-SEM), respectively. The FE-SEM images revealed that the grain size improved with increasing Cd²⁺ alloying in the CZTSSe thin films. Moreover, there was a slight decrease in small grain distribution as well as voids near the CZTSSe/Mo interface after Cd²⁺ alloying. The solar cells prepared using the most promising CZTSSe absorber thin films with Cd²⁺ alloying (8 min. 30 sec.) exhibited a power conversion efficiency (PCE) of 9.33 %, J_sc of 34.0 mA/cm², and fill factor (FF) of 62.7 %, respectively.

• Proceedings of the KSAR Conference
• /
• 2003.06a
• /
• pp.62-62
• /
• 2003

This study was carried out to investigate the effects of activation agents on parthenogenetic activation of pig oocytes matured in vitro. The medium used for oocyte maturation was tissue culture medium (TCM) 199 supplemented with 26.19 mM sodium bicarbonate, 0.9 mM sodium pyruvate, 10 $\mu\textrm{g}$/ml insulin, 2 $\mu\textrm{g}$/ml vitamin $B_{l2}$, 25 mM Hepes, 10 $\mu\textrm{g}$/ml bovine apotransferrin, 150 $\mu$M cysteamine, 10 IU/ml PMSG, 10 IU/ml hCG, 10 ng/ml EGF, 0.4% BSA, 75 $\mu\textrm{g}$/ml sodium penicillin G, 50 $\mu\textrm{g}$/ml streptomycin sulfate and 10% pFF. After about 22 h of culture, oocytes were cultured without cysteamine and hormones for 22 h at 38.5$^{\circ}C$, 5% $CO_2$ in air. Cumulus-free oocytes involving first polar body were activated by exposure to various concentrations of ethanol and exposure time of ethanol in Hepes-buffered NCSU23 medium. Also, oocytes were activated by electric pulse alone or combination with ethanol. For electrical activation, oocytes were rinsed twice in 0.3 M mannitol solution supplemented with 0.1 mM CaC1$_2$, 0.2 mM MgC1$_2$, 0.5 mM Hopes and 0.01% BSA, and transferred to a chamber consisting of two electrodes 1 mm apart which was overlaid with the same activation solution. Oocytes were activated with a single DC pulse of 1.3 ㎸/cm for 30 $\mu$sec. After activation treatments, oocytes were washed three times with Hepes-buffered NCSU23 medium and were washed twice with NCSU23 culture medium containing 0.4% BSA, and then cultured in 500 ${mu}ell$ of the same medium for 20 h at 38.5$^{\circ}C$, 5% $CO_2$ in air. The activation rates of oocytes were higher in 6, 7 and 8% ethanol concentrations compared with 0, 5, 9 and 10% ethanol concentrations. Significantly more oocytes (29.3~33.7%) were activated in the exposure for 8, 10, 12 and 15 min than those in the exposure for 0 and 5 min, but there was no difference due to exposure to 8% ethanol for 8 to 15 min. Electric pulse treatment followed by exposure to ethanol significantly improved the rate of oocyte activation (61.9%) compared with that of other 3 treatments. In conclusion, the optimal activation treatment of ethanol exposure alone for the in-vitro matured pig oocytes was 8% ethanol for 8 to 15 min. Electric pulse treatment followed by ethanol exposure significantly improved the rate of activation.n.

• The Journal of Korean Society for Radiation Therapy
• /
• v.26 no.2
• /
• pp.257-264
• /
• 2014

Purpose : Photoneutron dose in high-energy photon radiotherapy at linear accelerator increase the risk for secondary cancer. The purpose of this investigation is to evaluate the dose variation of photoneutron with different treatment method, flattening filter, dose rate and gantry angle in radiation therapy with high-energy photon beam ($E{\geq}8MeV$). Materials and Methods : TrueBeam $ST{\time}TM$(Ver1.5, Varian, USA) and Korea Tissue Equivalent Proportional Counter (KTEPC) were used to detect the photoneutron dose out of the high-energy photon field. Complex Patient plans using Eclipse planning system (Version 10.0, Varian, USA) was used to experiment with different treatment technique(IMRT, VMAT), condition of flattening filter and three different dose rate. Scattered photoneutron dose was measured at eight different gantry angles with open field (Field size : $5{\time}5cm$). Results : The mean values of the detected photoneutron dose from IMRT and VMAT were $449.7{\mu}Sv$, $2940.7{\mu}Sv$. The mean values of the detected photoneutron dose with Flattening Filter(FF) and Flattening Filter Free(FFF) were measured as $2940.7{\mu}Sv$, $232.0{\mu}Sv$. The mean values of the photoneutron dose for each test plan (case 1, case 2 and case 3) with FFF at the three different dose rate (400, 1200, 2400 MU/min) were $3242.5{\mu}Sv$, $3189.4{\mu}Sv$, $3191.2{\mu}Sv$ with case 1, $3493.2{\mu}Sv$, $3482.6{\mu}Sv$, $3477.2{\mu}Sv$ with case 2 and $4592.2{\mu}Sv$, $4580.0{\mu}Sv$, $4542.3{\mu}Sv$ with case 3, respectively. The mean values of the photoneutron dose at eight different gantry angles ($0^{\circ}$, $45^{\circ}$, $90^{\circ}$, $135^{\circ}$, $180^{\circ}$, $225^{\circ}$, $270^{\circ}$, $315^{\circ}$) were measured as $3.2{\mu}Sv$, $4.3{\mu}Sv$, $5.3{\mu}Sv$, $11.3{\mu}Sv$, $14.7{\mu}Sv$, $11.2{\mu}Sv$, $3.7{\mu}Sv$, $3.0{\mu}Sv$ at 10MV and as $373.7{\mu}Sv$, $369.6{\mu}Sv$, $384.4{\mu}Sv$, $423.6{\mu}Sv$, $447.1{\mu}Sv$, $448.0{\mu}Sv$, $384.5{\mu}Sv$, $377.3{\mu}Sv$ at 15MV. Conclusion : As a result, it is possible to reduce photoneutron dose using FFF mode and VMAT method with TrueBeam $ST{\time}TM$. The risk for secondary cancer of the patients will be decreased with continuous evaluation of the photoneutron dose.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.388-388
• /
• 2016

Chemical mist deposition (CMD) of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was investigated with cavitation frequency f, solvent, flow rate of nitrogen, substrate temperature $T_s$, and substrate dc bias $V_s$ as variables for efficient PEDOT:PSS/crystalline (c-)Si heterojunction solar cells (Fig. 1). The high-speed camera and differential mobility analysis characterizations revealed that average size and flux of PEDOT:PSS mist depend on f, solvent, and $V_s$. The size distribution of mist particles including EG/DI water cosolvent is also shown at three different $V_s$ of 0, 1.5, and 5 kV for a f of 3 MHz (Fig. 2). The size distribution of EG/DI water mist without PEDOT:PSS is also shown at the bottom. A peak maximum shifted from 300-350 to 20-30 nm with a narrow band width of ~150 nm for PEDOT:PSS solution, whose maximum number density increased significantly up to 8000/cc with increasing $V_s$. On the other hand, for EG/water cosolvent mist alone, the peak maximum was observed at a 72.3 nm with a number density of ~700/cc and a band width of ~160 nm and it decreased markedly with increasing $V_s$. These findings were not observed for PEDOT:PSS/EG/DI water mist. In addition, the Mie scattering image of PEDOT:PSS mist under white bias light was not observed at $V_s$ above 5 kV, because the average size of mist became smaller. These results imply that most of solvent is solvated in PEDOT:PSS molecule and/or solvent is vaporized. Thus, higher f and $V_s$ generate preferentially fine mist particle with a narrower band width. Film deposition occurred when $V_s$ was impressed on positive to a c-Si substrate at a Ts of $30-40^{\circ}C$, whereas no deposition of films occurred on negative, implying that negatively charged mist mainly provide the film deposition. The uniform deposition of PEDOT:PSS films occurred on textured c-Si(100) substrate by adjusting $T_s$ and $V_s$. The adhesion of CMD PEDOT:PSS to c-Si enhanced by $V_s$ conspicuously compared to that of spin-coated film. The CMD PEDOT:PSS/c-Si solar cell devices on textured c-Si(100) exhibited a ${\eta}$ of 11.0% with the better uniformity of the solar cell parameters. Furthermore, ${\eta}$ increased to 12.5% with a $J_{sc}$ of $35.6mA/cm^2$, a $V_{oc}$ of 0.53 V, and a FF of 0.67 with an antireflection (AR) coating layer of 20-nm-thick CMD molybdenum oxide $MoO_x$ (n= 2.1) using negatively charged mist of 0.1 wt% 12 Molybdo (VI) phosphoric acid n-Hydrate) $H_3(PMo_{12}O_40){\cdot}nH_2O$ in methanol. CMD. These findings suggest that the CMD with negatively charged mist has a great potential for the uniform deposition of organic and inorganic on textured c-Si substrate by adjusting $T_s$ and $V_s$.

• Microbiology and Biotechnology Letters
• /
• v.44 no.2
• /
• pp.130-139
• /
• 2016

A bacterial strain, producing an excellent lipolytic enzyme, was isolated from the intestinal tracts of an earthworm (Eisenia fetida). The strain was identified as Aeromonas hydrophila by phenotypic, chemotaxonomic characteristics and 16S ribosomal DNA analysis, and was designated as Aeromona hydrophila PL43. The lipolytic enzyme from A. hydrophila PL43 was purified via 35−45% ammonium sulfate precipitation, DEAE-sepharose fast flow ion-exchange, and sephacryl S-300HR gel filtration chromatography. The yield of the purified enzyme was 3.7% and 2.5% of the total activity of crude extracts with p-nitrophenyl butyrate (pNPB) and p-nitrophenyl palmitate (pNPP) as substrates, respectively. The molecular weight of the purified enzyme was approximately 74 kDa using gel filtration, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and zymography. The optimal activity of purified enzyme was observed at 50℃ and pH 8.0 using pNPB, and 60℃ and pH 8.0 using pNPP. The purified enzyme was stable in the ranges 20− 60℃ and pH 7.0−10.0. The activity of purified enzyme was inhibited by PMSF, pepstatin A, Co²⁺, Cu²⁺, and Fe²⁺, but was recovered by metal chelating of EDTA. The K_m and V_max values of the purified enzyme were 1.07 mM and 7.27 mM/min using pNPB and 1.43 mM and 2.72 mM/min using pNPP, respectively.

• Reproductive and Developmental Biology
• /
• v.29 no.3
• /
• pp.201-205
• /
• 2005

The objective of this study was to investigative the effects of amino acids supplementation on maturation, fertilization and embryo development of pig oocytes. Essential amino acids (EA), non-essential amino acids (NA) or both amino acids (EA + NA) were supple-mented to North Carolina State University (NCSU) 23 medium containing porcine follicular fluid (pFF). When the amino acids were supplemented to the maturation medium, the maturation rates were higher (p<0.05) in the NA group than control ($83.3{\pm}0.04\%\;versus\;70.0{\pm}0.05\%$, but the subsequent cleavage rates and development to morula and blstocyst stage between aminoacid supplement groups and control were not different. The developmental rates to morula and blastocysts stage were not significantly different regardless of amino acid supplementation to culture medium. In addition, supplementation of amino acids did not significantly affect the rate of fertilization and polyspermy. When the amino acids were supplement to culture medium, the number of trophectodermal (TE) cells was significantly (p<0.05) higher in amino acid supplement group than that of control ($18.6{\pm}0.5\;versus\;16.1{\pm}0.6$), whereas the numbers of inner cell mass (ICM) cells were not different among the treaonent groups and control ($29.0{\pm}0.9\~31.5{\pm}1.2$). Total cell number was also significantly (p<0.05) higher in EANA group ($50.0{\pm}1.0$) than that of control group ($44.2{\pm}1.1$). These results indicate that the amino acid supplementation to maturation and culture medium may not significantly stimulate early embryo development, but may improve the TE cell number of blastocyst stage in the pig.

• Journal of Embryo Transfer
• /
• v.19 no.3
• /
• pp.265-273
• /
• 2004

This study was carried out to examine the effects of fertilization media and sperm concentration on in vitro fertilization (IVF) and development (IVD) of porcine oocytes matured in vitro. Cumulus-oocyte complexes (COCs) were collected from antral follicles of porcine ovaries collected from abattoir, and were matured in vitro in modified NCSU-23 (mNCSU-23) supplemented with 10％ porcine follicular fluid (pFF). After the fertilization by experimental scheme, putative embryos were developed in vitro in NCSU-23. The results are as follows. When the oocytes were fertilized in vitro in modified TBM or modified TLP-PVA by 1 ${\times}$10$^{5}$ sperm/$m\ell$, all of the fertilization parameters were not significantly different between two media. Subsequently, as these putative embryos were developed in vitro in NCSU-23, the percentage of oocytes cleaved and of blastocysts were not different between two media, either. When the oocytes were fertilized in vitro in mTBM by 5${\times}$10$^4$, 1${\times}$10$^{5}$ or 5${\times}$10$^{5}$ sperm/$m\ell$, all of the fertilization parameters were significantly (P<0.05 or P<0.01) increased as sperm concentration was elevated. Subsequently, as these putative embryos were developed in vitro in NCSU-23, the percentage of oocytes cleaved and of blastocysts were significantly boosted (P<0.01) as sperm concentration at fertilization was elevated from 5${\times}$10$^4$ to 1${\times}$10$^{5}$ sperm/$m\ell$, but were not different between 1${\times}$10$^{5}$ and 5${\times}$10$^{5}$ sperm/$m\ell$.

• Clinics in Shoulder and Elbow
• /
• v.16 no.2
• /
• pp.73-83
• /
• 2013

Purpose: The goal of this study is to evaluate the minimum three-year follow-up results of reverse total shoulder arthroplasty (RTSA) for glenohumeral (GH) arthritic and pseudoparalytic patients with severe rotator cuff deficiency. Materials and Methods: We evaluated 13 patients (three males and 10 females) who underwent RTSA from July 2007 to July 2010. The average follow-up duration was 54.2 months (range, 37~74 months). Clinical results were evaluated using the Visual Analog Scale (VAS) for pain, active Range of Motion (ROM): active forward flexion (aFF); active external rotation at the side (aERs); active internal rotation to the back (aIRb), American Shoulder and Elbow Surgeons (ASES) score, Korean Shoulder Score (KSS), and intraoperative and postoperative complications. Results: VAS score improved from 7.5(6~10) points to 1.5(0~4), and ROM of active forward elevation improved from $42.7(10{\sim}100)^{\circ}$ to $129.1(110{\sim}180)^{\circ}$. In addition, ASES score improved from preoperative 32.9 (11.7~46.7) points to 80.2(58.3~95.0) postoperatively, and KSS score improved from 36.8(24~47) points to 78.4 (61~92). Twelve out of 13 cases showed various degrees of scapular notching at the last follow-up. There was one case of intraoperative anterior glenoid fracture and two cases of temporary nerve injury. Revision surgery was performed in two cases for treatment of delayed postoperative deep infection. Conclusion: According to minimum three-year follow-up results, RTSA may be an effective treatment option for glenohumeral (GH) arthritic and pseudoparalytic patients. However, considering the possibility of complications related to delayed deep infection or surgeon's technique, RTSA should be judiciously and carefully indicated by expert surgeons.

• Journal of Embryo Transfer
• /
• v.21 no.2
• /
• pp.101-107
• /
• 2006

The objective of this study was to investigative the effects of retinol supplement to IVM and/or IVC medium on maturation, fertilization and development of pig oocytes. North Carolina State University (NCSU) 23 medium containing porcine follicular fluid (pFF) was used as base medium. Each 1 uM, 5 uM and 10 uM concentration of retinol was supplemented to IVM and /or IVC medium. When the retinol was supplemented to maturation medium, the maturation rates were not different (p>0.05) among treatment groups ($66.7{\pm}6.0{\sim}69.2{\pm}5.3%$), but the developmental rate to blastocyst stage was higher (p<0.05) in $5{\mu}M$ group ($20.4{\pm}2.6%$) than in 0 uM ($13.6{\pm}2.1%$) and 10 uM groups ($9.7{\pm}1.7%$). Moreover, total cell number was significantly greater (p<0.05) in the 5 uM group ($37.0{\pm}1.6$) than in the other groups ($29.8{\pm}1.0{\sim}33.2{\pm}1.0$). Retinol supplement to maturation medium did not significantly affect the rates of fertilization and polyspermy (p>0.05). When the retinol was supplemented to culture medium or both maturation and culture medium, the rates of cleavage, and develop to morula and blastocyst stage were not affected, while those of 10 uM group were significantly decreased (p<0.05). These results indicate that 5 uM retinol supplement in maturation medium significantly stimulates embryo development, also improves the total cell number of blastocyst stage in pig.