• Title/Summary/Keyword: $Na_2S_2O_3$

Search Result 863, Processing Time 0.025 seconds

Composition and Temperature Dependence of Structural Changes in Borosilicate Glasses by Spectrometer (분광계에 의한 Borosilicate계 글라스의 조성 및 온도의존성 평가)

  • Park Sung-Je;Ryu Bong-Ki
    • Korean Journal of Materials Research
    • /
    • v.15 no.12
    • /
    • pp.786-790
    • /
    • 2005
  • We investigated the particularity of temperature and composition changes in $xNa_2O{\cdot}(52.5-x)B_2O_3{\cdot}47.5SiO_2$ glasses by use of FT-IR, $^{11}B$ NMR, Raman spectrometer. From FT-IR and $^{11}B$ NMR spectrometer, we thought that tetrahedral boron, $BO_4$ units are created $N_4$ increasing tendency generated near $600^{\circ}C$. It's expected that composition ana heat treatment directly contributed to structural changes, this changes are following to $Na_2O$ increasing or decreasing. caused by $N_4\;and\;BO_4$ units are caused by relatively increasing or decreasing in the glasses' structure. Particularly, $BO_4$ units are converted to $BO_3$ units after $600^{\circ}C$ heat treatment for 50h in the composition of $x<18(R<0.5,\;R=Na_2O/B_2O_3\;mol\%)$. On the order hand, $BO_3$ units are converted to, $BO_4$ units after $600^{\circ}C$ heat treatment for 50h in the composition of $x{\geq}18\;(R>0.5)$. This particularity of composition and temperature dependence of structural changes are similarly represented by Raman analysis results.

The Study of Glass Crystallization Mechanism Using Femtosecond Laser Pulse (극초단파레이저를 활용한 유리의 결정화 메커니즘 고찰)

  • Moon P.Y.;Yoon D.K.;Lee K.T.;Shin S.B.;Cho S.H.;Ryu B.K.
    • Transactions of Materials Processing
    • /
    • v.15 no.3 s.84
    • /
    • pp.213-219
    • /
    • 2006
  • To improve the strength of glass is being studied in order to contribute to weight saving of flat panel displays. Generally, the strength achieved of glass-ceramics is higher as is the fracture toughness by the formation of a heterogeneous phase inside glass. In this study, Ag-doped $45SiO_2-24CaO-24Na_2O-4P_2O_5\;and\;70SiO_2-10CaO-24Na_2O-10TiO_2$ glasses were irradiated to strengthen by crystallization using femto-second laser pulse. XRD, Nano-indenter and SEM etc., irradiation of laser pulse without heat-treated samples was analyzed. Samples irradiated by laser had higher value($4.4{\sim}4.56^*10-3Pa$) of elastic modulus which related with strength of glass than values heat-treated samples and these are $1.2{\sim}1.5$ times higher values than them of mother glass. This process can be applicable to the strengthening of thinner glass plate, and it has an advantage over traditional heat-treatment and ion-exchange method.

Tailoring Low-field Strain Properties of [0.97Bi1/2(Na0.78K0.22)1/2TiO3-0.03LaFeO3]-Bi1/2(Na0.82K0.18)1/2TiO3 Lead-Free Relaxor/Ferroelectric Composites (무연 완화형/정규 강유전체 복합소재 [0.97Bi1/2(Na0.78K0.22)1/2TiO3-0.03LaFeO3]-Bi1/2(Na0.82K0.18)1/2TiO3의 저전계 전계유기 변형 특성 연구)

  • Hong, Chang-Hyo;Kang, Jin-Kyu;Jo, Wook;Lee, Jae-Shin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.29 no.6
    • /
    • pp.342-347
    • /
    • 2016
  • We investigated the effect of $Bi_{1/2}(Na_{0.82}K_{0.18})_{1/2}TiO_3$ (BNKT) modification on the ferroelectric and electric-field-induced strain (EFIS) properties of lead-free $0.97Bi_{1/2}(Na_{0.82}K_{0.18})_{1/2}TiO_3-0.03LaFeO_3$ (BNKTLF) ceramics as a function of BNKT content (x= 0, 0.1, 0.2, 0.3, 0.5, and 1). BNKT-modified BNKTLF powders were synthesized using a conventional solid-state reaction method. As the BNKT content x increased from 0 to 1 the normalized electric-field-induced strain ($S_{max}/E_{max}$) was observed to increase at relatively low fields, i.e., below the poling field. Moreover, BNKTLF-30BNKT showed about 460 pm/V as low as at 3 kV/mm, which is a considerably high value among the lead-free systems reported so far. Consequently, it was confirmed that ceramic-ceramic composite, a mixture of an ergodic relaxor matrix and embedded ferroelectric seeds, is a salient way to make lead-free piezoelectrics practical with enhanced EFIS at low field as well as less hysterical.

Treatment Characteristics of Plating Wastewater Containing Freecyanide, Cyanide Complexes and Heavy Metals (I) (도금폐수내 유리시안과 착염시안 및 중금속의 처리특성 (I))

  • Jung, Yeon-Hoon;Lee, Soo-Koo
    • Journal of Korean Society on Water Environment
    • /
    • v.25 no.6
    • /
    • pp.979-983
    • /
    • 2009
  • The mean pH of wastewater discharged from the plating process is 2, so a less amount of alkali is required to raise pH 2 to 5. In addition, if sodium sulfite is used to raise pH 5 to 9 in the secondary treatment, caustic soda or slaked lime is not necessary or only a small amount is necessary because sodium sulfite is alkali. Thus, it is considered desirable to use only $FeSO_4{\cdot}7H_2O$ in the primary treatment. At that time, the free cyanide removal rate was highest as around 99.3%, and among heavy metals, Ni showed the highest removal rate as around 92%, but zinc and chrome showed a low removal rate. In addition, the optimal amount of $FeSO_4{\cdot}7H_2O$ was 0.3g/L, at which the cyanide removal rate was highest. Besides, the free cyanide removal rate was highest when pH value was 5. Of cyanide removed in the primary treatment, the largest part was removed through the precipitation of ferric ferrocyanide: $[Fe_4(Fe(CN)_6]_3$, and the rest was precipitated and removed through the production of $Cu_2[Fe(CN)_6]$, $Ni_2[Fe(CN)_6]$, CuCN, etc. Furthermore, it appeared more effective in removing residual cyanide in wastewater to mix $Na_2SO_3$ and $Na_2S_2O_5$ at an optimal ratio and put the mixture than to put them separately, and the optimal weight ratio of $Na_2SO_3$ to $Na_2S_2O_5$ was 1:2, at which the oxidative decomposition of residual cyanide was the most active. However, further research is required on the simultaneous removal of heavy metals such as chrome and zinc.

Leaching of Cathodic Active Materials from Spent Lithium Ion Battery (폐리튬이온전지로부터 분리한 양극활물질의 침출)

  • 이철경;김태현
    • Resources Recycling
    • /
    • v.9 no.4
    • /
    • pp.37-43
    • /
    • 2000
  • Leaching of $LiCoO_2$ as a cathodic active materials for recovering Li and Co from spent lithium ion battery was investigated in terms of reaction variables. At the optimum condition determined in the previous work, Li and Co in a $H_2SO_4$ and $HNO_3$ solution were dissolved 70~80% and 40%, respectively. Li and Co were leached over 95% with the addition of a reductant such as $Na_2S_2O_3$ or $H_2O_2$. This behavior is probably due to the reduction of $Co^{3+}$ to $Co^{2+}$. Leaching of $LiCoCo_2$ powder obtained by calcination of an electrode materials from spent batteries was also carried out. Leaching efficiency of Li and Co were over 99% at the optimum condition with $H_2O_2$ addition of 1.7 vol.%. It seems to be due to the activation of $LiCoO_2$ by repeated charging and discharging or an imperfect crystal structure by deintercalation of Li.

  • PDF

Thermal Storage Characteristics of $H_2O$-NaCl Mixtures for the Low Temperature Storage of Agricultural Products (농산물 저온 저장을 위한 $H_2O$-NaCl 혼합물의 축열 특성)

  • Song, H.K.;Ryou, Y.S.;Park, J.K.;Ro, J.G.
    • Solar Energy
    • /
    • v.17 no.3
    • /
    • pp.23-33
    • /
    • 1997
  • The theory on phase change temperature control and nucleation of PCM was suggested in this research. The crystallization model of PCM was established. And H2O-NaCl mixtures were selected as cold storage materials for agricultural products and thermo-physical properies of the PCM were analyzed with experimental processes including freeze-thaw cycles.

  • PDF

Properties of Modified Belite Cement with the Content of Clinker Minerals (클링커 광물 함량 변화시 Modified belite Cement의 특성)

  • 최연묵;이양수;김남호;최상홀
    • Journal of the Korean Ceramic Society
    • /
    • v.35 no.5
    • /
    • pp.479-485
    • /
    • 1998
  • Raw mateials such as limestone quartzite bauxite and anhydrite were used in the production of mod-ified beloite cement. Two kinds of clinker were synthesized with relatively higher content of $C_2S$ than that of $C_4A_3{\={S}}$ Concerning $C_2S$ the main mineral component borax ($Na_2O\;2B_2O_3\;10H_2O$) was added to stimu-late hydraulic reactivity and this would be possible by stabilizing ${\alpha}'-C_2S$ at room temperature. We had in-tended to compare burning and hydraulic characteristics of clinkers with one another by varying the amount of borax addition and to study the appropriate amount of anhydrite addition needed in the strengthening of cement during hydration. It was concluded that the effective amount of borax addition ne-eded for stabilization of ${\alpha}'-C_2S$ was 5 wt% in 60wt% $C_2S$ inclusive clinker and adding anhydrite in the ra-tio of 1.3 of $SO_3/Al_3O_3$ was appropriate in the production of cement by this clinker. Only ettringite was seen to contribute to the strength without additives but C-S-H was found to form along with ettringite with the addition of borax in the initial stage of hydration.

  • PDF

용액 공정 기반 ZrO2 절연막을 사용한 IGZO 박막 트랜지스터의 전기적 특성 향상 연구

  • Lee, Na-Yeong;Choe, Byeong-Deok
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2015.08a
    • /
    • pp.215.1-215.1
    • /
    • 2015
  • 본 연구에서는 용액 공정 기반 ZrO2 절연막의 우수한 특성을 확인하기 위해 SiO2 절연막을 가지는 IGZO (Indium-Gallium-Zinc Oxide) 박막 트랜지스터와 비교했다. In:Ga:Zn=1:1:1의 비율의 0.3 M IGZO 용액과 0.2 M ZrO2용액을 사용하였다. ZrO2 박막 트랜지스터는 0.2M ZrO2 용액을 5번 반복 증착하며 140nm 두께의 ZrO2 절연막을 가지는 IGZO 박막 트랜지스터와 비교대상으로 동일한 두께의 SiO2의 절연막을 가지는 IGZO 박막 트랜지스터를 제작하였다. ZrO2 박막 트랜지스터의 문턱전압은 4.3V로 SiO2 박막 트랜지스터의 -6.1V보다 낮았고, 이동도는 $1.2356cm^2/V{\cdot}s$$0.0554cm^2/V{\cdot}s$ 보다 약 20배 높았다. 실험 결과를 통해 ZrO2를 절연막으로 사용한 박막 트랜지스터의 특성이 더 향상되었음을 확인하였다.

  • PDF

Geochemistry and Stable Isotopes of Carbonated Waters in South Korea (남한 탄산수의 지구화학적 특성과 안정동위원소 조성)

  • 윤정아;김규한
    • Journal of the Korean Society of Groundwater Environment
    • /
    • v.7 no.3
    • /
    • pp.116-124
    • /
    • 2000
  • Geochemical and isotopic analyses were carried out to investigate hydrochemical characteristics, source of carbon species in the carbonated waters in South Korea. Most Korean carbonated waters from different geologic settings are characterized by a Ca-HCO$_3$type with a relatively low pH range from 5.3 to 6.3 (avg. 6.0). The concentrations of cations and anions in the carbonate waters are in the order of Ca$^{2+}$>Na$^{+}$>Mg$^{2+}$>Si$^{4+}$>Fe$^{2+}$>K$^{+}$ and HCO$_3$$^{-}$>SO$_4$$^{2-}$>Cl$^{-}$, respectively. The HCO$_3$$^{-}$ ion is more enriched in the carbonated water from the sedimentary rock and granitic rock of Mesozoic age in the Gyungsang basin(GII) and the Precambrian metamorphic rock and Jurassic granitic rocks of the Gyunggj massif in the Gangwon province(GⅠ) than those of the meta-sedimentary rock and granite in the Ogcheon zone(GⅢ). Based on the oxygen and hydrogen isotopic data, the carbonated waters are derived from the meteoric water, showing apparent latitude and altitude effects. The $delta$$^{13}$C values of carbon species in the carbonated water are in between -6.23 and 0.0 $textperthousand$, suggesting inorganic source of carbon originated from the carbonate mineral and carbonate rock in the aquifer.

  • PDF

Analysis on the Scales formed on the Heat Affected Zone of Low Carbon Steel Weld in NaCl and H2S Water Solutions (저탄소강 용접열영향부의 NaCl, H2S 수용액에서 생성되는 부식스케일 분석)

  • Kim, Min-Jung;Bae, Dong-Ho;Lee, Dong-Bok
    • Journal of the Korean institute of surface engineering
    • /
    • v.43 no.4
    • /
    • pp.205-210
    • /
    • 2010
  • The A106 Gr B low carbon steel, which was used in the electric power plants and heavy chemical plants, was welded by multi-pass arc welding. The heat affected zone (HAZ) formed by welding was corroded in acid chloride solution, or in saturated $H_2S$ containing acid chloride solution, or in saturated $H_2S$ containing acid chloride solution under applied current. In this order of corrosion solution, the rate of corrosion increased, because $H_2S$ accelerated the iron dissolution, hydrogen evolution, and the formation of nonprotective FeS, whereas the applied current accelerated the electrochemical reaction. The scales formed in acid chloride solution consisted primarily of $Fe_3O_4$, while those formed in $H_2S$ containing acid chloride solution consisted primarily of $Fe_3O_4$ and FeS.