• Title/Summary/Keyword: Sn addition

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Material Property Evaluation of High Temperature Creep on Pb-free Solder Alloy Joint to Reflow Time by Shear Punch-creep Test (전단펀치-크리프 시험에 의한 리플로우 시간별 Pb-free 솔더 합금 접합부에 대한 고온 크리프 물성 평가)

  • Ham, Young Pil;Heo, Woo Jin;Yu, Hyo Sun;Yang, Sung Mo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.21 no.1
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    • pp.145-153
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    • 2013
  • In this study, shear punch-creep (SP-Creep) at Sn-4Ag/Cu pad the joint was tested by using environment-friendly Pb-free solder alloy Sn-4Ag of electronic components. Pb eutectic alloy (Sn-37Pb) joints limited to environmental issues with reflow time (10sec, 30sec, 100sec, 300sec) according to two types of solder alloy joints are compared and evaluated by creep strain rate, rupture time and IMC (Intermetallic Compound) behavior. As the results, reflow time increases with increasing thickness of IMC can be seen at overall 100sec later in case of two solder joints on the IMC thickness of Sn-4Ag solder joints thicker than Sn-37Pb solder joints. In addition, when considering creep evaluation factors, lead-free solder alloy Sn-4Ag has excellent creep resistance more than Pb eutectic alloy. For this reason, the two solder joints, such as in the IMC (Cu6Sn5) was formed. However, the creep resistance of Sn-4Ag solder joints was largely increased in the precipitation strengthening effect of dispersed Ag3Sn with interface more than Sn-37Pb solder joints.

Effect of Hydrogen Ratio and Tin Addition on the Coke Formation of Platinum Catalyst for Propane Dehydrogenation Reaction (프로판 탈수소화 반응용 백금촉매의 코크 생성에 미치는 수소비와 주석첨가의 영향)

  • Kim, Soo Young;Kim, Ga Hee;Koh, Hyoung Lim
    • Clean Technology
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    • v.22 no.2
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    • pp.82-88
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    • 2016
  • The loss of activity by coke is an important cause of catalyst deactivation during industrial operation. In this study, hydrogen ratio of reaction condition, which has influenced on coke formation over Pt-Sn catalyst, and regeneration of catalysts activity by coke burning, Pt sintering of coke burning as coke contents, effects of coke formation and deactivation with different Sn contents were confirmed. Pt-Sn-K catalyst supported on θ-alumina and γ-alumina was prepared progressively. Activity of regenerated catalyst for propane dehydrogenation was compared with fresh catalyst by coke burning, after propane dehydrogenation was carried out with different hydrogen ratio at 620 ℃ on fresh catalyst. Regenerated catalyst’s physical characterization such as BET, coke analysis and XRD was investigated. Through catalytic activity test and characterization, Sn contents of catalyst and hydrogen ratio in feed stream could affect coke formation on catalyst surface. Excessive coke makes loss of activity and Pt sintering during air regeneration process.

Retardation of Massive Spalling by Palladium Layer Addition to Surface Finish (팔라듐 표면처리를 통한 Massive Spalling 현상의 억제)

  • Lee, Dae-Hyun;Chung, Bo-Mook;Huh, Joo-Youl
    • Korean Journal of Metals and Materials
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    • v.48 no.11
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    • pp.1041-1046
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    • 2010
  • The reactions between a Sn-3.0Ag-0.5Cu solder alloy and electroless Ni/electroless Pd/immersion Au (ENEPIG) surface finishes with various Pd layer thicknesses (0, 0.05, 0.1, 0.2, $0.4{\mu}m$) were examined for the effect of the Pd layer on the massive spalling of the $(Cu,Ni)_6Sn_5$ layer during reflow at $235^{\circ}C$. The thin layer deposition of an electroless Pd (EP) between the electroless Ni ($7{\mu}m$) and immersion Au ($0.06{\mu}m$) plating on the Cu substrate significantly retarded the massive spalling of the $(Cu,Ni)_6Sn_5$ layer during reflow. Its retarding effect increased with an increasing EP layer thickness. When the EP layer was thin (${\leq}0.1{\mu}m$), the retardation of the massive spalling was attributed to a reduced growth rate of the $(Cu,Ni)_6Sn_5$ layer and thus to a lowered consumption rate of Cu in the bulk solder during reflow. However, when the EP layer was thick (${\geq}0.2{\mu}m$), the initially dissolved Pd atoms in the molten solder resettled as $(Pd,Ni)Sn_4$ precipitates near the solder/$(Cu,Ni)_6Sn_5$ interface with an increasing reflow time. Since the Pd resettlement requires a continuous Ni supply across the $(Cu,Ni)_6Sn_5$ layer from the Ni(P) substrate, it suppressed the formation of $(Ni,Cu)_3Sn_4$ at the $(Cu,Ni)_6Sn_5/Ni(P)$ interface and retarded the massive spalling of the $(Cu,Ni)_6Sn_5$ layer.

Effect of Sodium Nitrite, Sodium Chloride and Concentrated Seawater on Physicochemical Properties of Meat Emulsion System

  • Lee, Sol-Hee;Kim, Hack-Youn
    • Food Science of Animal Resources
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    • v.40 no.6
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    • pp.980-989
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    • 2020
  • The objective of this study was to compare the effects of various salts on the physicochemical properties of pork emulsion sausages. Pork sausages were prepared using two different salts, sodium nitrite (SN) and sodium chloride (SC), and concentrated seawater (CSW). The CIE L*, CIE a*, and CIE b*, and chroma values of cooked and uncooked sausages with added CSW were significantly higher than those of the sausages with added SC (p<0.05). However, uncooked and cooked sausages with added SN and CSW had similar CIE a* values (p>0.05). The residual NO2- content of sausages with added CSW was significantly lower than that of sausages with added SN. Addition of CSW to sausages resulted in a higher cooking yield compared to the other treatments (p<0.05). Addition of SC resulted in significantly higher volatile basic nitrogen (VBN) and thiobarbituric acid (TBA) values compared to the other treatments. Furthermore, addition of CSW enhanced important physicochemical properties, including CIE a*, CIE b*, residual nitrite content, cooking yield, VBN, TBA, textural properties, and cross-sectional area.

Effects of P Addition and Homogenizing Heat Treatment on the Mechanical Properties of Centrifugal Cast Cu-Sn-Ni-P Alloy (원심주조한 Cu-Sn-Ni-Pb계 합금의 기계적 성질에 미치는 P첨가와 균질화 처리의 영향)

  • Kwon, Young-Hwan;Jea, Chang-Wooing;Yoon, Jae-Hong;Kang, Chang-Yong;Kim, Chang-Gyu
    • Journal of Korea Foundry Society
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    • v.17 no.5
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    • pp.443-449
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    • 1997
  • The purpose of this study is to investigate the effect of P addition and homogenizing heat treatment on the mechanical properties of Cu-Sn-Ni alloy. The addition of P was 0.025wt.%P to 0.085wt.%P and homogenizing heat-treated at 400, 500, $600^{\circ}C$ under $N_2$ gas atmosphere. Mechanical properties was investigated in this study were Rockwell hardness, tensile strength, and elongation. Tensile strength and elongation increased with P and homogenizing time. Temperature was significantly influence on mechanical properties. Hardness decreased with increasing homogenizing time and temperature, but 0.085wt.%P specimen was showed higher hardness and lower tensile strength and elongation than 0.073wt.%P specimen due to the presence of more $Cu_3P$ in matrix.

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Factors Affecting on Protein Stability of Mixed Cow and Soy Milk (콩우유와 우유 혼합유의 단백질 안정성에 미치는 영향인자)

  • 정남용;김우정
    • The Korean Journal of Food And Nutrition
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    • v.7 no.4
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    • pp.345-352
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    • 1994
  • High protein beverage of cow-soy milk was prepared by mixing the soymilk and commercial homogenized cow milk in the various ratios. Effect of heat treatment, pH and addition of calcium and sucrose was studied on the water-soluble nitrogen of cow-soy milk The heat-treated soymilk at 10$0^{\circ}C$ were centrifuged at the range of 830~29,900xg for 30 min and 11,200xg was found to be proper for determination of the degree of protein denaturation by centrifugal method. When soymilk was heated at 70~10$0^{\circ}C$ for 30~240 min, soluble nitrogen (QA SN) in supernatant of protein was decreased to 78.0~56.8% due to protein denaturation. Most of heat denaturation of protein was found to be occurred during Initial heating 10$0^{\circ}C$ for all mixed cow-soy milk. The sedimentation of SN was maximum at pH 4.0 In the range of pH 3~8. Addition of sucrose affected little on oASN while calcium addition reduced %SN significantly to approx. 55% for soymilk(100%). The effect of Ca was less as the ratio of cow milk increased.

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Effects of Alloying Elements on the Mechanical Properties of Normalized and Quenched 3.60wt%C-2.60wt%Si Ductile Cast Irons Poured into Shell Stack Mold (쉘 스택 주조 3.60wt%C-2.60wt%Si 조성 구상흑연주철의 Normalizing 및 Quenching 처리 시 기계적 성질에 미치는 합금 원소의 영향)

  • Kim, Hyo-Min;Kwon, Hae-Wook;Yeo, In-Dong;Nam, Won-Sick
    • Journal of Korea Foundry Society
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    • v.30 no.2
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    • pp.66-75
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    • 2010
  • The effects of alloying elements on the mechanical properties of normalized and quenched 3.60wt%C-2.60wt%C ductile cast iron poured into shell stack mold were investigated. The strength and hardness of as-cast specimen were increased and the elongation of it was decreased with the additions of Mn, Cu and Sn. The strength and hardness were increased with the addition of 0.40wt%Mo and then rather decreased with the increased addition of 0.80wt%. The strength and hardness were increased with normalizing treatment and the strengths of normalized specimens were increased slightly with the addition of alloying elements except Mo. Meanwhile the yield strength of the normalized specimen was increased slightly with the addition of Mo, the tensile strength was not changed much. Meanwhile the hardness and strength of the quenched specimen were slightly increased with the addition of Mn, those were almost not changed with the amount added. The tensile strength of the quenched specimen with larger diameter, when the Cu had been added, and the tensile and yield strengths of them, when Mo had been added, were increased with the addition of alloying element. On the other hand, those were not changed with the amount added. For the case of specimen with smaller diameter, there were no effects of these two elements. When Sn had been added, the strength of hardened specimen with larger diameter was slightly increased with the amount added. However, that with smaller diameter was rather decreased with it. The effect of specimen diameter on the strength of quenched specimen with the addition of Cu, Mo and Sn was reduced.

Characterization and antimicrobial efficacy of Portland cement impregnated with silver nanoparticles

  • Nam, Ki Young
    • The Journal of Advanced Prosthodontics
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    • v.9 no.3
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    • pp.217-223
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    • 2017
  • PURPOSE. This study investigated the effects of silver nanoparticle (SN) loading into hydraulic calcium silicate-based Portland cement on its mechanical, antibacterial behavior and biocompatibility as a novel dental bone substitute. MATERIALS AND METHODS. Chemically reduced colloidal SN were combined with Portland cement (PC) by the concentrations of 0 (control), 1.0, 3.0, and 5.0 wt%. The physico-mechanical properties of silver-Portland cement nanocomposites (SPNC) were investigated through X-ray diffraction (XRD), setting time, compressive strength, solubility, and silver ion elution. Antimicrobial properties of SPNC were tested by agar diffusion against Streptococcus mutans and Streptococcus sobrinus. Cytotoxic evaluation for human gingival fibroblast (HGF) was performed by MTS assay. RESULTS. XRD certified that SN was successfully impregnated in PC. SPNC at above 3.0 wt% significantly reduced both initial and final setting times compared to control PC. No statistical differences of the compressive strength values were detected after SN loadings, and solubility rates of SPNC were below 3.0%, which are acceptable by ADA guidelines. Ag ion elutions from SPNC were confirmed with dose-dependence on the concentrations of SN added. SPNC of 5.0 wt% inhibited the growth of Streptococci, whereas no antimicrobial activity was shown in control PC. SPNC revealed no cytotoxic effects to HGF following ISO 10993 (cell viability > 70%). CONCLUSION. Addition of SN promoted the antibacterial activity and favored the bio-mechanical properties of PC; thus, SPNC could be a candidate for the futuristic dental biomaterial. For clinical warrant, further studies including the inhibitory mechanism, in vivo and long-term researches are still required.

HYDROGEN PLASMA DURABILITY OF $SnO_2$:F FILMS (불소 도핑 이산화주석 박막의 수소플라즈마 내구성)

  • Yoon, Kyung-Hoon;Song, Jin-Soo;kang, Kee-Hwan
    • Proceedings of the KIEE Conference
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    • 1992.07b
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    • pp.847-849
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    • 1992
  • Fluorine-doped ($SnO_2$:F) thin films obtained by pyrosol deposition method have been exposed to R.F. excited pure hydrogen plasma under the following conditions; substrate temperature of 200$^{\circ}C$, $H_2$ pressure of 1 Torr, R.F. input power of 50 mW/$\textrm{cm}^{2}$, $H_2$ flow rate of 30cc/min and exposure time of 15-600 seconds. It is found that the sheet resistance of the films remains unchanged or rather slightly reduces for initial exposure time of 30-60 seconds, but increases sharply with further increasing the exposure time. The optical transmittance of $SnO_2$:F films slows a rapid fall with increasing exposure time except for a film obtained with a solution having $CH_3OH/H_2O$ mol ratio of 2.65, its degradations at the exposure time of 30-60 seconds are about 7-15%. In addition, the exposure of the films to hydrogen plasma atmosphere leads to remarkable changes in the microstructure and chemical composition, which should be attributed to the reduction of $SnO_2$ to SnO and to elemental Sn.

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Ultrafast Time-Resolved Laser Spectroscopic Studies of trans-Bis(ferrocene-carboxylato)(tetraphenyl-porphyrinato)tin(IV): Intramolecular Electron-Transfer Dynamics

  • Jang, Joon-Hee;Kim, Hee-Jung;Kim, Hee-Joon;Kim, Chul-Hoon;Joo, Tai-Ha;Cho, Dae-Won;Yoon, Min-Joong
    • Bulletin of the Korean Chemical Society
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    • v.28 no.11
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    • pp.1967-1972
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    • 2007
  • Photophysical properties of a newly-synthesized porphyrin derivative, trans-bis(ferrocene carboxylato)- (5,10,15,20-tetraphenylporphyrinato)tin(IV) [Sn(TPP)(FcCOO)2] were investigated by means of steady-state and fs-time resolved laser spectroscopic techniques, and compared with those of a standard molecule, trans-dichloro( 5,10,15,20-tetraphenyl-porphrinato)tin(IV) [Sn(TPP)Cl2]. The fluorescence spectrum of Sn(TPP)- (FcCOO)2 was observed to exhibit dual emission bands originating from the S2-state and the S1-state, which was greatly quenched as compared to those of Sn(TPP)Cl2. The fs-time resolved fluorescence and transient absorption spectroscopic measurements revealed that the fluorescence quenching is due to formation of the long-lived charge transfer state by intramolecular electron transfer from ferrocene to the S2-excited SnTPP in addition to the enhanced non-radiative deactivation processes.