• 제목/요약/키워드: Secondary Phase

검색결과 1,057건 처리시간 0.05초

Sintering Characteristics of ZnO Fabricated by Spark Plasma Sintering Process for High Temperature Thermoelectric Materials Application (고온용 ZnO계 열전 재료의 방전플라즈마 소결 특성 및 미세구조)

  • 심광보;김경훈;홍영호;채재홍
    • Journal of the Korean Ceramic Society
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    • 제40권6호
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    • pp.560-565
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    • 2003
  • M-doped (M=Al, Ni) ZnO thermoelectric materials were fully densified at low temperatures of 800∼1,000$^{\circ}C$ and their sintering characteristics and microstructural features were investigated. Electron microscopic analysis showed that the addition of NiO promoted tile formation of solid solution and caused actively grain growth. The addition of A1$_2$O$_3$ prevented the evaporation of pure ZnO at grain boundaries and suppressed the grain growth by the formation of secondary phase. In case of the addition of A1$_2$O$_3$ together with NiO, the specimen showed an excellent microstructure and also the SEM-EBSP (Electron Back-scattered Diffraction Pattern) analysis confirmed that it shows a superior grain boundary distribution to the others specimens. These microstructural characteristics induced by the addition of A1$_2$O$_3$ together with NiO may increase the electrical conductivity by the increase in carrier concentration and decrease the thermal conductivity by the phonon scattering effect and, consequently, improve the thermoelectric property.

A Study on the Consolidation Settlement Due to the Vertical Drain Method by the Implicit Finite Difference Scheme (음적차분해석법을 이용한 연직배수 공법에 의한 압밀침하에 관한 연구)

  • Park, Sung Zae;Jung, Du Hwoe;Jeong, Gyeong Hwan;Lee, Kyeong Joon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제14권5호
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    • pp.1243-1251
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    • 1994
  • The implicit finite difference program was developed to evaluate the relationship between time and consolidation ratio within the zone of vertical drain effective radius. In the evaluation, the excess pore water pressure was considered to dissipate in two directions, namely, vertical and radial flow direction. To calculate subsoil stress increments in the soil due to multi-step embanking, the foundation soil was assumed to be an isotropic and homogeneous elastic medium and the initial excess pore water pressure was estimated by using Skempton's parameters whose condition is plane strain and elastic phase of pore pressure response within the soft ground. Regarding to the settlement estimation, immediate and primary consolidation settlements were calculated. The secondary or delayed consolidation settlement was not considered. Numerically calculated excess pore water pressure and settlements were similar to the measured data in situ. Thus, this method can be used to predict the time-consolidation ratio of each layer treated by vertical drain method.

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Design and Evaluation of Aluminum Casting Alloys for Thermal Managing Application (방열소재용 알루미늄 주조합금 설계 및 특성평가)

  • Shin, Je-Sik;Kim, Ki-Tae;Ko, Se-Hyun;An, Dong-Jin;Kim, Myung-Ho
    • Journal of Korea Foundry Society
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    • 제33권1호
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    • pp.22-31
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    • 2013
  • In order to develop an aluminum alloy, that can combine high thermal conductivity and good castability and anodizability, aluminum alloys with low Si content, such as Al-(0.5~1.5)Mg-1Fe-0.5Si and Al-(1.0~1.5)Si-1Fe-1Zn, were designed. The developed aluminum alloys exhibited 170~190% thermal conductivity (160~180 W/mK), 60~85% fluidity, and equal or higher ultimate tensile strength compared with those of the ADC12 alloy. In each developed alloy system, the thermal conductivity decreased and the strength increased with the increment of Mg and Si, which are the significant alloying elements. The fluidity was in reverse proportion to the Mg content and in proportion to the Si content. The Al-(0.5~1.5)Mg-1Fe-0.5Si alloys exhibited better fluidity in thick-wall castings, while the Al-(1.0~1.5)Si-1Fe-1Zn alloys were better in thin-wall castability due to their lower surface energies. The fluidity behavior was complexly affected by the heat release for the solidification, viscosity, solidification range, and the type, quantity, and formation juncture of the main secondary phase.

Study on the Gelling Formation and Anti-gelling Properties of Liquid Detergent Based on Sodium Lauryl Ethoxy Sulfate (SLES) (소듐 라우릴 에톡시 설페이트(SLES) 베이스 액체세정제의 겔링성 및 겔링방지 특성에 대한 연구)

  • Chi, Gyeong-Yup
    • Applied Chemistry for Engineering
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    • 제29권5호
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    • pp.620-625
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    • 2018
  • Liquid detergent based on sodium lauryl ethoxy sulfate (SLES) as main ingredient sometimes met gelling film on the surface when it is opened in the air. It was assumed because of the change of phase diagram of micelle by concentration change of surfactant, major ingredient of detergent when the water of detergent is evaporated. SLES showed strong hexagonal liquid crystal (LC) in 30~60 wt%, and lamellar LC over 60 wt%. In this research surface gelling formation of liquid detergent which is based on SLES as main ingredient was because of water evaporation. As water of detergent was evaporated, concentration of surfactant became higher. It was checked that surface gelling was LC of mixed surfactant system. Conclusionally we applied alpha olefin sulfonate (AOS) having good solubility, Sodium secondary alkane sulfonate (SAS) preventing hexagonal LC and hydrotrope sodium xylene sulfonate (SXS) and PEG1500 in order to prevent gelling film in SLES based liquid detergent. Like this, improved formula 4 and 5 can prevent the formation of gelling film on the surface of liquid detergent when it is opened in the air.

131I-Labeled-Metuximab Plus Transarterial Chemoembolization in Combination Therapy for Unresectable Hepatocellular Carcinoma: Results from a Multicenter Phase IV Clinical Study

  • Ma, Jun;Wang, Jian-Hua
    • Asian Pacific Journal of Cancer Prevention
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    • 제16권17호
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    • pp.7441-7447
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    • 2015
  • Objective: This study evaluated the safety and objective response of combining $^{131}I$-labeled-metuximab (Licartin) with transarterial chemoembolization (TACE) in the treatment of unresectable hepatocellular carcinoma (HCC). Materials and Methods: In a multicenter open-label clinical trial, 341 enrolled patients with stage III/IV HCC according to TNM criteria were nonrandomly assigned to a trial group (n=167) and a control group (n=174), undergoing TACE following hepatic intra-arterial injection of licartin or TACE alone from July 2007 to July 2009. Radiopharmaceutical distribution was evaluated. The primary endpoint was overall survival; secondary endpoints included time-to-progression (TTP), toxicity and adverse events (AEs). Results: The radiobiological distribution demonstrated better localization of licartin in liver tumors than other tissues (P<0.01). The organ absorbed doses to liver and red marrow were $3.19{\pm}1.01Gy$ and $0.55{\pm}0.22Gy$, respectively. The 1-year survival rate was significantly higher [79.47% vs. 65.59%, hazard ratio (HR), 0.598, P=0.041] and TTP significantly improved ($6.82{\pm}1.28$ vs. $4.7{\pm}1.14months$, P=0.037) compared with the control group. Patients at stage III achieved more benefit of one year survival than stage IV in the trial group (86.9% vs. 53.8%, P<0.001). There were significant different toxicities in leukocytopenia, thrombocytopenia and increased total bilirubin level [P<0.001, P=0.013, P<0.01, relative risk (RR) 1.63, 1.33, 1.43], but no differences in severe AEs of upper GI hemorrhage and severe liver dysfunction between the groups (5.39% vs. 2.3%, P=0.136). Conclusions: Owing to excellent tumor-targeting, promised efficacy and favourable toxicity profile, the novel combination therapy of licartin and TACE could be applied in patients with unresectable HCC.

Poultry industry of Bangladesh: entering a new phase

  • Rahman, Md Shahidur;Jang, Dong-Heon;Yu, Chan-Ju
    • Korean Journal of Agricultural Science
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    • 제44권2호
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    • pp.272-282
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    • 2017
  • In Bangladesh, since the beginning of 21st century, the poultry industry has become an unparalleled platform for a quick profit, the generation of local employment, and the production of cheaper animal proteins. This paper summarizes poultry industry-related facts and figures for Bangladesh, starting from the very beginnings of this sector when poultry farming was part of subsistence family farming only to today's highly commercialized horizon, through personal experiences, secondary data analysis, spot visits, and the sharing of views and ideas with stakeholders. A critical analysis reveals that the poultry industry in Bangladesh may become multi-dimensional and more stable in the near future as it establishes sufficient backward and forward linkages to input and output supplies. We can foresee its passing the very fast growing juvenile stages of higher net profit earning and less responsible then becoming fully mature. The projected demand and production potentials of this sector are increasing, but at a slower pace than before, in the face of some important challenges like emerging disease, higher prices of inputs, consumer preferences, and strong market competition. However, evidence suggests that the production systems of poultry in Bangladesh are entering a new era to cater to the needs of consumers, society, and government as it produces healthier and more diversified, further-processed foods, in the coming years. A better economy in the country, a more health-conscious population, and the availability of new and affordable innovations in this sector might be the driving forces to support the foreseen transformations.

Interfacial Reaction between Ultra-Small 58Bi-42Sn Solder Bump and Au/Ni/Ti UBM for Ultra-Fine Flip Chip Application (고집적 플립 칩용 극미세 58Bi-42Sn 솔더 범프와 Au/Ni/Ti UBM의 계면 반응)

  • Kang, Woon-Byung;Jung, Yoon;Kim, Young-Ho
    • Journal of the Microelectronics and Packaging Society
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    • 제10권2호
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    • pp.61-67
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    • 2003
  • The interfacial reaction between ultra-small 58Bi-42Sn solder and Au/Ni/Ti under bump metallurgy (UBM) for ultra-fine flip chip application was investigated. The ultra-small 58Bi-42Sn solder bump, about $46{\mu}m$ in diameter, was fabricated by using the lift-off method and reflowed using the rapid thermal annealing (RTA) system. The intermetallic compounds were characterized using a secondary electron microscopy (SEM), an energy dispersive spectroscopy (EDS), and an x-ray diffractometer (XRD). The faceted and polygonal intermetallic compounds were found in the Bi-Sn solder bumps on $Au(0.1{\mu}m)/Ni/Ti$ UBM and they were indentified as $(Au_xBi_yNi_{1-x-y})Sn_2$ Phase. The intermetallic compounds grown from the $Au(0.1{\mu}m)/Ni/Ti$ UBMinterface were dispersed in the solder bump.

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Effects of Y2O3 Addition on Densification and Thermal Conductivity of AlN Ceramics During Spark Plasma Sintering (Y2O3 첨가가 AlN 세라믹스의 방전 플라즈마 소결 거동 및 열전도도에 미치는 영향)

  • Chae, Jae-Hong;Park, Joo-Seok;Ahn, Jong-Pil;Kim, Kyoung-Hun;Lee, Byung-Ha
    • Journal of the Korean Ceramic Society
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    • 제45권12호
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    • pp.827-831
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    • 2008
  • Spark plasma sintering (SPS) of AlN ceramics were carried out with ${Y_2}{O_3}$ as sintering additive at a sintering temperature $1,550{\sim}1,700^{\circ}C$. The effect of ${Y_2}{O_3}$ addition on sintering behavior and thermal conductivity of AlN ceramics was studied. ${Y_2}{O_3}$ added AlN showed higher densification rate than pure AlN noticeably, but the formation of yttrium aluminates phases by the solid-state reaction of ${Y_2}{O_3}$ and ${Al_2}{O_3}$ existed on AlN surface could delay the densification during the sintering process. The thermal conductivity of AlN specimens was promoted by the addition of ${Y_2}{O_3}$ up to 3 wt% in spite of the formation of YAG secondary phase in AlN grain boundaries because ${Y_2}{O_3}$ addition could reduced the oxygen contents in AlN lattice which is primary factor of thermal conductivity. However, the thermal conductivity rather decreased over 3 wt% addition because an immoderate formation of YAG phases in grain boundary could decrease thermal conductivity by a phonon scattering surpassing the contribution of ${Y_2}{O_3}$ addition.

Meta-analysis of Six Randomized Control Trials of Chemotherapy Plus Anti-HER Monoclonal Antibody for Advanced Gastric and Gastroesophageal Cancer

  • Luo, Huai-Qing;Han, Li;Jiang, Yan
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권13호
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    • pp.5343-5348
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    • 2014
  • Background: A meta-analysis was performed to examine the benefit/risk ratio for the addition of anti- HER MoAbs to chemotherapy in patients with advanced gastric and gastroesophageal cancer from six randomized phase II/III trials. Materials and Methods: We searched relative trials from Pubmed, EMBASE, Cochrane library databases, China National Knowledge Infrastructure databases, Google Scholar and the NIH ClinicalTrials. Primary outcomes were overall response rate (ORR), progression-free survival (PFS), overall survival (OS). Secondary outcomes were toxicities. All analyses were performed using STATA 12.0. Results: This meta-analysis included six randomized controlled trials (RCTs) with 2, 297 patients and we demonstrated that the anti-HER MoAbs arm did have a positive effect on ORR in the anti-HER MoAbs arm (OR 1.28, 95% CI 1.00-1.64, p=0.01). There was an increasing benefit regarding OS (HR 0.74, 95% CI 0.60-0.88, p<0.05) and PFS (HR 0.72, 95% CI 0.60-0.84, p<0.05) in the anti-HER2 subgroup, but a reduction of OS (HR 1.11, 95% CI 0.87-1.36, p<0.05) and PFS (HR 1.13, 95% CI 0.98 -1.28, P<0.05) in anti-EGFR subgroup. Some grade 3-4 toxicity had a significantly higher incidence in the anti-HER MoAbs arm. There was no significant publication bias for all endpoints. Conclusions: The addition of trstuzumab MoAb to chemotherapy for gastric and gastroesophageal cancer significantly improved outcome of OS and PFS endpoints, while other MoAbs led to no improvement in results. Some adverse events were increased in anti-HER MoAbs arm compared with the control.

Chemical Stability of Lithium Lanthanum Titanate (Li0.5La0.5TiO3) as a Solid Electrolyte for Lithium Secondary Batteries

  • Eun, Yeong-Jin;Im, Wan-Gyu;Lee, Won-Jun
    • Proceedings of the Korean Vacuum Society Conference
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.202.1-202.1
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    • 2014
  • 최근 대용량 에너지 저장장치로 사용하고자 하는 리튬-공기전지는 리튬 음극과 액체 전해질 사이의 화학적 불안정성이 문제가 되고 있다. 또한 리튬이온전지는 액체전해질의 사용으로 인해 폭발 등의 안정성 문제가 대두되고 있는 실정이다. 때문에 리튬-공기전지에서 리튬 음극을 액체 전해질로부터 보호할 수 있으며, 리튬이온전지의 액체전해질과 대체하였을 때 전극과도 안정한 고체전해질의 연구가 필요하다. 고체전해질은 구조적으로 crystalline, glassy, 폴리머로 나눌 수 있는데, 이 중 crystalline 구조의 고체전해질은 glassy 및 폴리머 고체전해질에 비해 상온에서 비교적 이온전도도가 높다고 알려져 있다 [1]. 그러나 이온전도도가 높은 황화물 및 질화물 고체전해질은 수분에 민감한 반면 [2,3], 산화물 계열의 물질은 안정할 것으로 예상된다. 본 연구에서는 이온전도도가 높은 산화물인 lithium lanthanum titanate ($Li_{0.5}La_{0.5}TiO_3$, LLTO)를 고체전해질로 선정하여 다양한 환경에서 화학적 안정성에 관해 연구하였다. LLTO와 각종 용액과의 화학적 안정성을 살펴보기 위해 고체전해질을 DI water, 1 M $LiPF_6$ Ethylene Carbonate (EC)-Dimethyl Carbonate (DMC) (50:50 vol.%), 0.57 M LiOH (pH=13), 0.1 M HCl (pH=1)에 immersion하고 무게, 표면형상, 상(phase), 이온전도도 등의 변화를 관찰하였다. 또한 LLTO와 전극간의 반응성을 알아보기 위해 LLTO 분말과 음극물질인 $Li_4Ti_5O_{12}$ 및 양극물질인 $LiCoO_2$ 분말을 혼합한 후 $300^{\circ}C{\sim}700^{\circ}C$의 온도범위에서 열처리하여 반응을 가속화 한 후 상변화 현상을 살펴보았다.

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