$Sr_{1-x}Ca_xGa_2S_4:Ce,Na$ 형광체의 합성과 발광 특성

성혜진,허영덕,Sung, Hye-Jin,Huh, Young-Duk 한국결정성장학회 2006 韓國結晶成長學會誌 Vol.16 No.6

A series of $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$ phosphors have been synthesized by solid-state reaction. The photoluminescence and structural properties of $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$ have been examined. The $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$ phosphors have a strong absorption at 400 nm, which is the emission wavelength of a violet light emitting diode (LED). The emission peaks of $SrGa_2S_4:Ce,Na$are located at 448 nm and 485 nm. The partial replacement of Sr by Ca in $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$ causes a red shift of emission wavelengths. The $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$ can be used as blue emitting phosphors pumped by the violet LED for fabricating the multi-band white LED. 일련의 $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$ 형광체를 고상법으로 합성하였다. $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$의 구조와 발광 특성을 조사하였다. $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$은 보라색 발광 다이오드의 발광 파장인 400 nm에서 강한 흡수가 있다. $SrGa_2S_4:Ce,Na$의 발광 봉우리는 448 nm와 485 nm에 있다. $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$에서 Sr이 Ca으로 부분 치환되면 발광 파장이 장파장으로 이동된다. 다파장 백색 LED를 제작할 때 $Sr_{1-x}Ca_xGa_2S_4:Ce,Na$은 보라색 LED로 여기하여 청색 발광 형광체로 사용 될 수 있다.

Increase in conversion efficiency of above 14% in Cu(In,Ga)₃Se₅ (β-CIGS) solar cells by Na₂S incorporation through the surface of β –CIGS film

Kim, Ji Hye,Kim, Seung Tae,Larina, Liudmila,Ahn, Byung Tae,Kim, KiHwan,Yun, Jae Ho Elsevier 2018 Solar energy materials and solar cells Vol.179 No.-

<P><B>Abstract</B></P> <P>Little work has been reported on the performance improvement of the β-CIGS solar cell itself even though the β-CIGS phase can have an ideal band gap for high-conversion efficiency solar cells. We incorporated Na<SUB>2</SUB>S to β-CIGS film by supplying Na<SUB>2</SUB>S to three different stages: on the (In,Ga)<SUB>2</SUB>Se<SUB>3</SUB> layer, on the α-CIGS layer, and on the β -CIGS layer in the three-stage co-evaporation process. The purpose of Na<SUB>2</SUB>S incorporation was to control the carrier concentration and passivate grain boundaries in β–CIGS film. With Na<SUB>2</SUB>S incorporation on the β–CIGS surface, both the Cu and Se concentrations at the β–CIGS surface were greatly reduced and the Na-depleted subsurface area that existed in the referenced β–CIGS film without Na<SUB>2</SUB>S was eliminated. The carrier concentration determined at 100kHz was lowest with Na<SUB>2</SUB>S incorporation on the β–CIGS surface, while that determined at 1MHz was similar with various Na<SUB>2</SUB>S supply stages. The open-circuit voltage and fill factor greatly increased in the β–CIGS solar cell with the Na<SUB>2</SUB>S incorporation. The cell conversion efficiency with Na<SUB>2</SUB>S incorporation on the β-CIGS layer improved from 10.3% to 14.2% without AR coating, which is a record efficiency in β-CIGS solar cells at this time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The performance of Cu(In,Ga)<SUB>3</SUB>Se<SUB>5</SUB> (β-CIGS) solar cell was improved by Na<SUB>2</SUB>S doping. </LI> <LI> Na<SUB>2</SUB>S was supplied on the surfaces of (In,Ga)<SUB>2</SUB>Se<SUB>3</SUB>, α-CIGS layer, and β -CIGS layers. </LI> <LI> Na<SUB>2</SUB>S on the β–CIGS surface reduced both the Cu and Se concentrations at the surface. </LI> <LI> Na<SUB>2</SUB>S on the β–CIGS surface eliminated the Na depletion zone in the CIGS film. </LI> <LI> The cell conversion efficiency improved from 10.3% to 14.2% without AR coating. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>(a) A schematic three-stage co-evaporation process for Cu(In,Ga)<SUB>3</SUB>Se<SUB>5</SUB> (β-CIGS) film with Na<SUB>2</SUB>S incorporation at various stages and (b) J-V curves of the β–CIGS solar cell with the best efficiency of 14.2% without antireflective coating by Na<SUB>2</SUB>S incorporation on the β–CIGS layer (③).</P> <P>[DISPLAY OMISSION]</P>

Determination of NaOH, $Na_2CO_3$ and $Na_2S$ Concentration in a Naphtha Cracking Process by FT-NIR Spectroscopy

장미진,김현욱,조일영,Jang, Mijin,Kim, Hyunwook,Cho, Ilyoung 한국분석과학회 1998 분석과학 Vol.11 No.6

납사 그랙킹 공정과정에서 사용되는 caustic 농도와 부산물로 형성되는 $Na_2CO_3$, $Na_2S$ 농도를 신속하고 정확하게 분석할 수 있는 검량법의 개발과 근적외선 분광기의 적용가능성에 대하여 연구하였다. 주성분 회귀분석을 이용한 검량법과 근적외선 분광기의 조합은 현재 사용되고 있는 습식 적정법의 대체 분석법으로 빠르고 비파괴적으로 적용 가능한 기기이며, 0.1 표준예측오차의 정밀한 분석을 할 수 있다. The feasibility of using FT-NIR (Fourier Transform Near Infrared) spectrometer to measure NaOH, $Na_2CO_3$ and $Na_2S$ concentration in a naphtha cracking process, and an outline of the method development to identify spectral feature of the hydroxide whose band is overlapped by a strong water absorption were demonstrated. For measuring NaOH, $Na_2CO_3$ and $Na_2S$, FT-NIR spectrometer is a rapid and possible alternative to the current titration method with a standard deviation of 0.1.

Na₂S 하부층을 이용한 Cu(In,Ga)Se₂ 광흡수층의 저온증착 및 Cu(In,Ga)Se₂ 박막태양전지에의 응용

신해나라,신영민,김지혜,윤재호,박병국,안병태,Shin, Hae Na Ra,Shin, Young Min,Kim, Ji Hye,Yun, Jae Ho,Park, Byung Kook,Ahn, Byung Tae 한국태양광발전학회 2014 Current Photovoltaic Research Vol.2 No.1

High-efficiency in $Cu(In,Ga)Se_2$ (CIGS) solar cells were usually achieved on soda-lime glass substrates due to Na incorporation that reduces deep-level defects. However, this supply of sodium from sodalime glass to CIGS through Mo back electrode could be limited at low deposition temperature. Na content could be more precisely controlled by supplying Na from known amount of an outside source. For the purpose, an $Na_2S$ layer was deposited on Mo electrode prior to CIGS film deposition and supplied to CIGS during CIGS film. With the $Na_2S$ underlayer a more uniform component distribution was possible at $350^{\circ}C$ and efficiency was improved compared to the cell without $Na_2S$ layer. With more precise control of bulk and surface component profile, CIGS film can be deposited at low temperature and could be useful for flexible CIGS solar cells.

Na2S를 이용한 EDTA 토양세척수로부터의 중금속 분리

오상화,신원식 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.7

Soil washing with ethylenediaminetetraacetic acid (EDTA) is highly effective in the remediation of soils contaminated with heavy metals. The EDTA recycling process is a requisite for reducing the operating cost. The applicability of Na2S addition on the precipitation of heavy metals from the spent soil washing solution and thereby recycling of EDTA was investigated. Addition of Na2S into the single metal-EDTA and the mixed metal-EDTA solutions ([Na2S]/[metal-EDTA] ratio = 30, reaction time = 30 min and pH = 7~9) was highly effective in the separation of Cu and Pb from metal-EDTA complexes, but not for Ni. The Zn removal efficiency varied with pH and slightly increased upto 40% as the reaction time increased from 0 to 240 min which was longer than those for Cu and Pb. Ca(OH)2 was subsequently added to induce further precipitation of Zn and Ni and to reduce the Na2S dose. At the [Na2S]/[metal-EDTA] ratio of 10, the removal efficiencies of all heavy metals excluding Ni were above 98% with the dose of Ca(OH)2 at 0.002, 0.006 and 0.008 g into 100 mL of Cu-, Pb- and Zn-EDTA solutions, respectively. However, Ca(OH)2 addition was not effective for Ni-EDTA solution. A further research is needed to improve metal removal efficiency and subsequent EDTA recycling for the real application in field-contaminated soils.

Effect of Na doping using Na₂S on the structure and photovoltaic properties of CIGS solar cells

Shin, Young Min,Shin, Dong Hyeop,Kim, Ji Hye,Ahn, Byung Tae Elsevier 2011 CURRENT APPLIED PHYSICS Vol.11 No.1

<P><B>Abstract</B></P><P>Na doping in CIGS film is one of the most crucial factors that affects the performance of CIGS solar cells. However, the role of Na doping is not yet well understood. In this study, in order to find an effective Na doping method, Na was doped into CIGS film using Na<SUB>2</SUB>S precursor at three different points in the three-stage co-evaporation and its effect on CIGS film was investigated. The microstructures, Na doping profiles and bonding states were examined using scanning electron microscope, x-ray diffraction, secondary ion mass spectroscopy and x-ray photoelectron spectroscopy. It was found that the external sodium doping with Na<SUB>2</SUB>S changed the microstructure and the Na doping profile. The performance of a CIGS solar cell with the external Na doping on Mo/Corning glass was worse than that of a conventional CIGS solar cell fabrication. The best performance achieved by means of Na external doping was 14.2% efficiency, which was achieved when Na was doped by depositing a Na<SUB>2</SUB>S precursor layer on a Mo metal layer.</P>

Na₂S를 이용한 EDTA 토양세척수로부터의 중금속 분리

오상화,신원식,Oh, Sanghwa,Shin, Won Sik 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.7

Soil washing with ethylenediaminetetraacetic acid (EDTA) is highly effective in the remediation of soils contaminated with heavy metals. The EDTA recycling process is a requisite for reducing the operating cost. The applicability of Na₂S addition on the precipitation of heavy metals from the spent soil washing solution and thereby recycling of EDTA was investigated. Addition of Na₂S into the single metal-EDTA and the mixed metal-EDTA solutions ([Na₂S]/[metal-EDTA] ratio = 30, reaction time = 30 min and pH = 7~9) was highly effective in the separation of Cu and Pb from metal-EDTA complexes, but not for Ni. The Zn removal efficiency varied with pH and slightly increased upto 40% as the reaction time increased from 0 to 240 min which was longer than those for Cu and Pb. Ca(OH)₂ was subsequently added to induce further precipitation of Zn and Ni and to reduce the Na₂S dose. At the [Na₂S]/[metal-EDTA] ratio of 10, the removal efficiencies of all heavy metals excluding Ni were above 98% with the dose of Ca(OH)₂ at 0.002, 0.006 and 0.008 g into 100 mL of Cu-, Pb- and Zn-EDTA solutions, respectively. However, Ca(OH)₂ addition was not effective for Ni-EDTA solution. A further research is needed to improve metal removal efficiency and subsequent EDTA recycling for the real application in field-contaminated soils.

Hydrogen sulfide donor, NaHS, stimulates ANP secretion via the K_ATP channel and the NOS/sGC pathway in rat atria

Yu, Lamei,Park, Byung Mun,Ahn, Yong Jin,Lee, Gi-Ja,Kim, Suhn Hee Elsevier 2019 Peptides Vol.111 No.-

<P><B>Abstract</B></P> <P>Hydrogen sulfide (H<SUB>2</SUB>S) is normally produced from <SMALL>L</SMALL>-cysteine in mammalian tissues and related to the pathogenesis of cardiovascular diseases. The aim of this study is to investigate the effects of H<SUB>2</SUB>S donor on atrial natriuretic peptide (ANP) secretion and define its mechanism using normal and isoproterenol (ISP)-treated rats. Several H<SUB>2</SUB>S donors were perfused into isolated beating rat atria, and atrial pressure (AP) and ANP secretion were measured. NaHS augmented high stretch-induced ANP secretion and decreased AP in a dose-dependent manner. The high stretch-induced ANP secretion was stimulated by Na<SUB>2</SUB>S but was not changed by GYY4137 and sodium thiosulfate. NaHS and Na<SUB>2</SUB>S produced very high amount of H<SUB>2</SUB>S rapidly whereas GYY4137 produced very low amount of H<SUB>2</SUB>S slowly. NaHS-stimulated ANP secretion was blocked by the pretreatment with inhibitor for K<SUB>ATP</SUB> channel, nitric oxide synthase (NOS), soluble guanylyl cyclase (sGC), phosphoinositol 3 kinase (PI3K) or protein kinase B. H<SUB>2</SUB>S synthesis enzyme inhibitor (DL-propargylglycine) did not show any significant changes in atrial parameters. However, the response of ANP secretion to NaHS markedly attenuated and DL-propargylglycine suppressed ANP secretion in ISP-treated rat atria. The expression of eNOS protein was decreased but the expression of cardiomyocyte-specific H<SUB>2</SUB>S producing enzyme, cystathione γ-lyase, was not changed in ISP-treated rat atria. The attenuation of NaHS-induced ANP secretion in ISP-treated rat atria may be due to the low expression of eNOS protein. These findings clarify that NaHS stimulates ANP secretion via the K<SUB>ATP</SUB> channel and the PI3K/Akt/NOS/sGC pathway in rat atria.</P> <P><B>Highlights</B></P> <P> <UL> <LI> NaHS and Na<SUB>2</SUB>S augmented high stretch-induced ANP secretion whereas GYY4137 and sodium thiosulfate did not. </LI> <LI> NaHS-stimulated ANP secretion was blocked by the pretreatment with inhibitor for K<SUB>ATP</SUB> channel, NOS, sGC, PI3K or protein kinase B. </LI> <LI> The attenuation of NaHS-induced ANP secretion in ISP-treated rat atria may be due to the low expression of eNOS protein. </LI> <LI> These findings clarify that NaHS stimulates ANP secretion through the K<SUB>ATP</SUB> channel and PI3K/Akt/NOS/sGC pathway. </LI> </UL> </P>

고로슬래그 시멘트 페이스트의 초기 균열에서의 자기치유에 미치는 Na2SO4의 영향

이승헌,김홍주,임영진,김동현,박병선 한국콘크리트학회 2019 콘크리트학회논문집 Vol.31 No.3

본 연구에서는 고로슬래그 미분말의 자극제로 사용하는 Na2SO4를 5 % 첨가한 고로슬래그 시멘트 페이스트의 초기 자기치유 생성물의 특성에 대해 검토하였다. 균열에서의 주된 자기치유 생성물은 C-S-H, CaCO3로서 Na2SO4 첨가는 무첨가와 비교하여 3.7배 정도 더 많은 자기치유 생성물을 형성시켰다. Na2SO4에 의한 자기치유 증진 효과는 균열 면에서의 미수화 고로슬래그 입자와 시멘트 입자의 수화반응을 촉진시켜 C-S-H의 생성량을 증가시키고 동시에 형성되는 Ca(OH)2는 균열 내 용액 중의 탄산이온 및 공기 중의 CO2와 반응하여 Calcite로 전환된 것으로 판단된다. 또한 Na2SO4 첨가는 균열 내 용액의 Na+ 이온과 SO42- 이온의 농도를 증가시켜 수분 증발 시 Alkali Carbonate, Alkali Sulfate로 석출되었다. 자기치유 생성물 형태를 보면 Calcite는 작은 알갱이 형태, C-S-H는 그물 형태, Alkali Carbonate은 대형 결정 형태, Alakli Sulphate은 길쭉한 판상 형태를 나타냈으며 Na2SO4가 첨가된 계는 결정이 성장되어 무첨가보다 큰 형태로 성장하였다.

Precipitation of La and dissolution enhancement of Ni by a one pot oxidative leaching process from mixed batteries

Sung-Ho Joo,Dong Ju Shin,Dongseok Lee,Min-seuk Kim,Shun Myung Shin 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.88 No.-

A single oxidative leaching process was developed for simultaneous enhancement of dissolution of nickeland precipitation of lanthanum by using Na2S2O8 in sulfuric acid solution from a heat-treated mixture ofbatteries containing 50 wt.% alkaline batteries, 25 wt.% Ni-MH batteries, and 25 wt.% Ni-Cd batteries. Theeffect of leaching parameters was investigated, including the concentrations of sulfuric acid, Na2S2O8, andH2O2, the temperature, and the leaching time. The results show that almost all metals such as zinc,manganese, and cadmium are dissolved by 2 M sulfuric acid, but the leaching efficiency of nickel is 86.8%. However, in a leaching process using Na2S2O8, the leaching efficiency of Ni is enhanced while lanthanum isselectively precipitated in the form of NaLa(SO4)2 H2O at the same time, and this result is supported by XRD,ICP, and SEM analysis. Under the optimum conditions of 2 M H2SO4,10 vol.% H2O2,10 vol.% 1 M Na2S2O8, and95℃,97.8% of the nickel is leachedwhile98.8% of thelanthanumisselectively precipitated.Thisstudyshowsthat the separation and purification stages can be simplified to recover La and valuable metals.