To see the other types of publications on this topic, follow the link: PROC MCMC.
Journal articles on the topic 'PROC MCMC'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 19 journal articles for your research on the topic 'PROC MCMC.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Ames, Allison J., and Kelli Samonte. "Using SAS PROC MCMC for Item Response Theory Models." Educational and Psychological Measurement 75, no. 4 (September 25, 2014): 585–609. http://dx.doi.org/10.1177/0013164414551411.
Full text
2
McNeish, Daniel. "Fitting Residual Error Structures for Growth Models in SAS PROC MCMC." Educational and Psychological Measurement 77, no. 4 (June 1, 2016): 587–612. http://dx.doi.org/10.1177/0013164416652441.
Full textAbstract:
In behavioral sciences broadly, estimating growth models with Bayesian methods is becoming increasingly common, especially to combat small samples common with longitudinal data. Although M plus is becoming an increasingly common program for applied research employing Bayesian methods, the limited selection of prior distributions for the elements of covariance structures makes more general software more advantages under certain conditions. However, as a disadvantage of general software’s software flexibility, few preprogrammed commands exist for specifying covariance structures. For instance, PROC MIXED has a few dozen such preprogrammed options, but when researchers divert to a Bayesian framework, software offer no such guidance and requires researchers to manually program these different structures, which is no small task. As such the literature has noted that empirical papers tend to simplify their covariance matrices to circumvent this difficulty, which is not desirable because such a simplification will likely lead to biased estimates of variance components and standard errors. To facilitate wider implementation of Bayesian growth models that properly model covariance structures, this article overviews how to generally program a growth model in SAS PROC MCMC and then demonstrates how to program common residual error structures. Full annotated SAS code and an applied example are provided.
3
Menke, Jan. "Bivariate Random-Effects Meta-analysis of Sensitivity and Specificity with the Bayesian SAS PROC MCMC." Medical Decision Making 33, no. 5 (March 8, 2013): 692–701. http://dx.doi.org/10.1177/0272989x13475719.
Full text
4
Pinski, Francis J. "A Novel Hybrid Monte Carlo Algorithm for Sampling Path Space." Entropy 23, no. 5 (April 22, 2021): 499. http://dx.doi.org/10.3390/e23050499.
Full textAbstract:
To sample from complex, high-dimensional distributions, one may choose algorithms based on the Hybrid Monte Carlo (HMC) method. HMC-based algorithms generate nonlocal moves alleviating diffusive behavior. Here, I build on an already defined HMC framework, hybrid Monte Carlo on Hilbert spaces (Beskos, et al. Stoch. Proc. Applic. 2011), that provides finite-dimensional approximations of measures π, which have density with respect to a Gaussian measure on an infinite-dimensional Hilbert (path) space. In all HMC algorithms, one has some freedom to choose the mass operator. The novel feature of the algorithm described in this article lies in the choice of this operator. This new choice defines a Markov Chain Monte Carlo (MCMC) method that is well defined on the Hilbert space itself. As before, the algorithm described herein uses an enlarged phase space Π having the target π as a marginal, together with a Hamiltonian flow that preserves Π. In the previous work, the authors explored a method where the phase space π was augmented with Brownian bridges. With this new choice, π is augmented by Ornstein–Uhlenbeck (OU) bridges. The covariance of Brownian bridges grows with its length, which has negative effects on the acceptance rate in the MCMC method. This contrasts with the covariance of OU bridges, which is independent of the path length. The ingredients of the new algorithm include the definition of the mass operator, the equations for the Hamiltonian flow, the (approximate) numerical integration of the evolution equations, and finally, the Metropolis–Hastings acceptance rule. Taken together, these constitute a robust method for sampling the target distribution in an almost dimension-free manner. The behavior of this novel algorithm is demonstrated by computer experiments for a particle moving in two dimensions, between two free-energy basins separated by an entropic barrier.
5
Wagner, Markus, Stipan Jonjić, Ulrich H. Koszinowski, and Martin Messerle. "Systematic Excision of Vector Sequences from the BAC-Cloned Herpesvirus Genome during Virus Reconstitution." Journal of Virology 73, no. 8 (August 1, 1999): 7056–60. http://dx.doi.org/10.1128/jvi.73.8.7056-7060.1999.
Full textAbstract:
ABSTRACT Recently the mouse cytomegalovirus (MCMV) genome was cloned as an infectious bacterial artificial chromosome (BAC) (M. Messerle, I. Crnković, W. Hammerschmidt, H. Ziegler, and U. H. Koszinowski, Proc. Natl. Acad. Sci. USA 94:14759–14763, 1997). The virus obtained from this construct is attenuated in vivo due to deletion of viral sequences and insertion of the BAC vector. We reconstituted the full-length MCMV genome and flanked the BAC vector with identical viral sequences. This new construct represents a versatile basis for construction of MCMV mutants since virus generated from the construct loses the bacterial sequences and acquires wild-type properties.
6
Deng, Yajun, Hanyun Ma, Jinyong Hao, Qiqi Xie, and Ruochen Zhao. "MCM2 and NUSAP1 Are Potential Biomarkers for the Diagnosis and Prognosis of Pancreatic Cancer." BioMed Research International 2020 (April 29, 2020): 1–20. http://dx.doi.org/10.1155/2020/8604340.
Full textAbstract:
Pancreatic cancer (PC) is one of the most malignant tumors. Despite considerable progress in the treatment of PC, the prognosis of patients with PC is poor. The aim of this study was to identify potential biomarkers for the diagnosis and prognosis of PC. First, the original data of three independent mRNA expression datasets were downloaded from the Gene Expression Omnibus and The Cancer Genome Atlas databases and screened for differentially expressed genes (DEGs) using the R software. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of the DEGs were performed, and a protein-protein interaction (PPI) network was constructed to screen for hub genes. The hub genes were analyzed for genetic variations, as well as for survival, prognostic, and diagnostic value, using the cBioPortal and Gene Expression Profiling Interactive Analysis (GEPIA) databases and the pROC package. After screening for potential biomarkers, the mRNA and protein levels of the biomarkers were verified at the tissue and cellular levels using the Cancer Cell Line Encyclopedia, GEPIA, and the Human Protein Atlas. As a result, a total of 248 DEGs were identified. The GO terms enriched in DEGs were related to the separation of mitotic sister chromatids and the binding of the spindle to the extracellular matrix. The enriched pathways were associated with focal adhesion, ECM-receptor interaction, and phosphatidylinositol 3-kinase (PI3K)/AKT signaling. The top 20 genes were selected from the PPI network as hub genes, and based on the analysis of multiple databases, MCM2 and NUSAP1 were identified as potential biomarkers for the diagnosis and prognosis of PC. In conclusion, our results show that MCM2 and NUSAP1 can be used as potential biomarkers for the diagnosis and prognosis of PC. The study also provides new insights into the underlying molecular mechanisms of PC.
7
Akter, Mst Afroza, Marc Caldwell, Gina Pighetti, and Liesel G. Schneider. "49 Hematological and physiological changes observed in commercial stocker operation during early management." Journal of Animal Science 98, Supplement_4 (November 3, 2020): 33–34. http://dx.doi.org/10.1093/jas/skaa278.060.
Full textAbstract:
Abstract Dynamic physiological parameters’ change in recently received stocker calves may indicate disease onset or further progression. Our objective was to capture changes in rectal temperature and blood chemistry to determine relationships between these responses, castration status, and time after arrival at a commercial farm. Forty newly weaned steers of variable breed and body weight were received from order buyer on February 13, 2020 to a commercial stocker farm in Crossville. Calves were monitored for 4 wks; blood samples and rectal temperature were collected at day 0, 7, 14, and 21. All calves were either freshly (FC) (n = 27) or previously castrated (PC) (n = 13). Complete blood count (CBC) was analyzed on each sampling day using Hematology Analyzer, and the correlation between body temperature and CBC parameters was assessed using CORR procedure in SAS 9.4. To test if FC group differed from PC with CBC value changes, mixed model analysis of variance was performed (Proc GLIMMIX) with day as repeated measure (α = 0.05). Rectal temperature was significantly negatively correlated with red blood cells (RBC) (r = -0.33, P = 0.03) and hemoglobin (HGB) (r = -0.37, P = 0.01) on day 21. A castration by day interaction (P = 0.04) was found for white blood cell (WBC). Significant differences were found in between FC and PC groups for WBC on day 0 (10.59 and 14.23, respectively) and 14 (12.04 and 15.80, respectively). Significantly lower RBC, HGB, and Mean Corpuscle Volume (MCV) were found in FC; however, they had increased Mean Corpuscle Hemoglobin (MCH) and platelet (PLT) counts (P < 0.05). In addition, there were day effects on mean WBC, MCH, PLT, and Mean Corpuscular Hemoglobin Concentration (MCHC) (P < 0.001). While previous health history of stocker cattle remains unknown, there are definite differences in hematology and physiology at arrival and over time, which may increase risk for illness in this stage of production.
8
Bonnefoy, M., K. Perraut, A. M. Lagrange, P. Delorme, A. Vigan, M. Line, L. Rodet, et al. "The GJ 504 system revisited." Astronomy & Astrophysics 618 (October 2018): A63. http://dx.doi.org/10.1051/0004-6361/201832942.
Full textAbstract:
Context. The G-type star GJ504A is known to host a 3–35 MJup companion whose temperature, mass, and projected separation all contribute to making it a test case for planet formation theories and atmospheric models of giant planets and light brown dwarfs. Aims. We aim at revisiting the system age, architecture, and companion physical and chemical properties using new complementary interferometric, radial-velocity, and high-contrast imaging data. Methods. We used the CHARA interferometer to measure GJ504A’s angular diameter and obtained an estimation of its radius in combinationwith the HIPPARCOS parallax. The radius was compared to evolutionary tracks to infer a new independent age range for the system. We collected dual imaging data with IRDIS on VLT/SPHERE to sample the near-infrared (1.02–2.25 μm) spectral energy distribution (SED) of the companion. The SED was compared to five independent grids of atmospheric models (petitCODE,Exo-REM, BT-SETTL, Morley et al., and ATMO) to infer the atmospheric parameters of GJ 504b and evaluate model-to-model systematic errors. In addition, we used a specific model grid exploring the effect of different C/O ratios. Contrast limits from 2011 to 2017 were combined with radial velocity data of the host star through the MESS2 tool to define upper limits on the mass of additional companions in the system from 0.01 to 100 au. We used an MCMC fitting tool to constrain the companion’sorbital parameters based on the measured astrometry, and dedicated formation models to investigate its origin. Results. We report a radius of 1.35 ± 0.04 R⊙ for GJ504A. The radius yields isochronal ages of 21 ± 2 Myr or 4.0 ± 1.8 Gyr for the system and line-of-sight stellar rotation axis inclination of 162.4−4.3+3.8 degrees or 186.6−3.8+4.3 degrees. We re-detect the companion in the Y2, Y3, J3, H2, and K1 dual-band images. The complete 1–4 μm SED shape of GJ504b is best reproduced by T8-T9.5 objects with intermediate ages (≤ 1.5Gyr), and/or unusual dusty atmospheres and/or super-solar metallicities. All atmospheric models yield Teff = 550 ± 50 K for GJ504b and point toward a low surface gravity (3.5–4.0 dex). The accuracy on the metallicity value is limited by model-to-model systematics; it is not degenerate with the C/O ratio. We derive log L∕L⊙ = −6.15 ± 0.15 dex for the companion from the empirical analysis and spectral synthesis. The luminosity and Teff yield masses of M = 1.3−0.3+0.6 MJup and M = 23−9+10 MJup for the young and old age ranges, respectively. The semi-major axis (sma) is above 27.8 au and the eccentricity is lower than 0.55. The posterior on GJ 504b’s orbital inclination suggests a misalignment with the rotation axis of GJ 504A. We exclude additional objects (90% prob.) more massive than 2.5 and 30 MJup with semi-major axes in the range 0.01–80 au for the young and old isochronal ages, respectively. Conclusions. The mass and semi-major axis of GJ 504b are marginally compatible with a formation by disk-instability if the system is 4 Gyr old. The companion is in the envelope of the population of planets synthesized with our core-accretion model. Additional deep imaging and spectroscopic data with SPHERE and JWST should help to confirm the possible spin-orbit misalignment and refine the estimates on the companion temperature, luminosity, and atmospheric composition.
9
Stone, Clement, and Brian Leventhal. "Accounting for Multidimensionality in Item Responses in Patient-Centered and Patient Reported Outcomes Measurement." International Journal of Person Centered Medicine 6, no. 4 (February 2, 2017). http://dx.doi.org/10.5750/ijpcm.v6i4.614.
Full textAbstract:
Background: More robust and rigorous psychometric models, such as Item Response Theory (IRT) models, have been advocated for applications measuring health sciences outcomes. However, there are challenges to the use of IRT models with health assessments. In particular, item responses from measuring health-related outcomes are typically determined by multiple traits or dimensions. This multidimensionality can be caused by various factors including designed multidimensional structure to the instrument, heterogeneity in item content, and from other sources such as differential item functioning in subpopulations and individual differences in response styles to survey items and rating scales. Objectives: This paper discusses different extensions to IRT models that can be used to account for different types of multidimensionality as well as the use of Bayesian methods with person-centered medicine research.Methods: Use of the SAS PROC MCMC platform for implementing Bayesian analyses is illustrated to estimate and analyze IRT applications to health-related assessments. Results: PROC MCMC involves a straightforward translation of the response probability model along with specifications of the model parameters and prior distributions for the model parameters. Conclusions: Bayesian analysis of multidimensional IRT models is more accessible to researchers and scale developers in measuring health sciences outcomes for person-centered medicine research.
10
Windover, Donald, D. L. Gil, J. P. Cline, A. Henins, N. Armstrong, P. Y. Hung, S. C. Song, R. Jammy, and A. Diebold. "X-Ray Reflectometry Determination of Structural Information from Atomic Layer Deposition Nanometer-scale Hafnium Oxide Thin Films." MRS Proceedings 996 (2007). http://dx.doi.org/10.1557/proc-0996-h07-05.
Full textAbstract:
AbstractThis work demonstrates the application of a Markov Chain Monte Carlo (MCMC) approach to modeling X-ray reflectometry (XRR) data taken from a sub 10 nm Hafnium oxide film. We present here a comparison of two structural models for a 6 nm HfxOy atomic layer deposition (ALD) film on Si. Using the MCMC method and two distinct structural models, we show evidence of a thin interface between the HfxOy and Si layers with a density much higher than native SiO2. Results from genetic algorithm XRR analysis and thickness measurements using cross-sectional transmission electron microscopy are included for comparison. We also demonstrate that our interpretation of HfxOy thickness differs between the two structural models (i.e., total film thicknesses may be partially additive within each model).
11
Yang, S. H., S. Morris, S. Tian, K. Parab, A. F. Tasch, P. M. Echenique, R. Capaz, and J. Joannopoulos. "A New Local Electronic Stopping Model for the Monte Carlo Simulation of Arsenic Ion Implantation into (100) Single-Crystal Silicon." MRS Proceedings 389 (1995). http://dx.doi.org/10.1557/proc-389-77.
Full textAbstract:
ABSTRACTIn this paper is reported the development and implementation of a new local electronic stopping model for arsenic ion implantation into single-crystal silicon. Monte Carlo binary collision (MCBC) models are appropriate for studying channeling effects since it is possible to include the crystal structure in the simulators. One major inadequacy of existing MCBC codes is that the electronic stopping of implanted ions is not accurately and physically accounted for, although it is absolutely necessary for predicting the channeling tails of the profiles. In order to address this need, we have developed a new electronic stopping power model using a directionally dependent electronic density (to account for valence bonding) and an electronic stopping power based on the density functional approach. This new model has been implemented in the MCBC code, UT-MARLOWE The predictions of UT-MARLOWE with this new model are in very good agreement with experimentally-measured secondary ion mass spectroscopy (SIMS) profiles for both on-axis and off-axis arsenic implants in the energy range of 15-180 keV.
12
Chilakamarri, Prasad, Ilango Meyyappan, H. A. Naseem, and W. D. Brown. "Au/Ti and Au/Ni-Cr Metallization of CVD Diamond Substrates for Multichip Module Applications." MRS Proceedings 323 (1993). http://dx.doi.org/10.1557/proc-323-195.
Full textAbstract:
AbstractMultichip Modules (MCMs) have recently received widespread attention in the electronics industry. Owing to its high thermal conductivity, CVD diamond holds great promise for solving thermal management problems in MCMs. Also, large diameter free standing diamond substrates have recently become available. It is thus necessary to develop a reliable metallization for diamond substrates. As Au does not adhere to diamond, refractory metals, viz., Ti, W and Mo have been used as glue layers, as they form carbides above 800 °C. Since CVD diamond looses its properties at these temperatures, there is a need to obtain adherent metallizations at much lower temperatures. In the work reported here, tenaciously adherent Au/Ti and Au/Ni80-Cr20 metallization systems were sputter deposited on CVD diamond substrates for potential use as interconnects in MCMs. The adhesion values obtained by Sebastian V stud pull tester were in the range of 12 Kpsi, with post-deposition anneal temperature as low as 150 °C. The key to good adhesion was preconditioning of the diamond surface using in-situ sputter-etch technique. The effect of post-deposition annealing (up to 450 °C) on the interdiffusion of Au with the underlying metals was studied using AES, EDX, Optical Microscopy and sheet resistance measurements. Results indicate mixing of C from diamond with refractory metals at low temperatures which may be contributing to strong adhesion.
13
Shoji, C., T. Matsuo, A. Suzuki, and Y. Yamamasu. "Development of Electrolyte plate for Molten Carbonate Fuel Cell." MRS Proceedings 496 (1997). http://dx.doi.org/10.1557/proc-496-211.
Full textAbstract:
ABSTRACTIt is important for the commercialization of molten carbonate fuel cell (MCFC) to improve the endurance and the reliability of the electrolyte plate. The electrolyte-loss in the electrolyte plate increases the cell resistance and deteriorates the cell voltage. The formation of cracks in the electrolyte plate causes a gas cross leakage between the fuel gas and the oxidizer gas. The pore structure of electrolyte plate must be stable and fine to support liquid electrolyte under MCFC operation. It is necessary to prevent the formation of cracks in electrolyte plate during thermal cycling. We have improved the stability of electrolyte plate using advanced LiAIO2powder and improved the durability of electrolyte plate for thermal cycling by the addition of the ceramic fiber.The initial cell voltage using electrolyte plate with advanced LiAIO2powder was 820mV at current density 150mA/cm2and the decay rate of cell voltage was under 0.5%/1000h for 8,800h. According to the post analyses, the pore structure of the electrolyte plate did not change. The stability of advanced LiAIO2powder was confirmed. It was proved that the electrolyte plate reinforced with ceramic fiber is effective for thermal cycling.
14
Flynn, J., and C. Marsh. "Improved Carbon Anode Materials for Lithium-Ion Cells." MRS Proceedings 496 (1997). http://dx.doi.org/10.1557/proc-496-613.
Full textAbstract:
ABSTRACTSeveral carbon materials have been studied for suitability as anode materials in lithium-ion cells. Carbons that have been included in this evaluation are three grades of commercially available mesophase carbon microbeads (MCMB) 6–28, 10–28 and 25–28, two specially prepared mesophase fibers (Amoco), a foreign mesophase fiber and KS-15 graphite (Lonza). Differences in cycling behavior between the three types of MCMB material are shown. Data of full lithium-ion cells demonstrate the effect that the choice of carbon material has on the cell discharge voltage and capacity. Lithium reference electrode experiments in full cells (3.0–4.0Ah capacity), elucidate the dynamics under several charge/discharge regimes and provide a comparison between the performance of carbon fiber and graphite anode materials. These test results indicate that the fibers can be charged at significantly higher rates than graphite without showing polarization at the anode. Full and half cell data also demonstrates the high coulombic efficiencies of the mesophase materials and first cycle efficiencies as compared to graphite. A comparison of two mesophase materials with different textures in full cells under strenuous cycling conditions shows significant differences in capacity retention. SEM photos of fibers showing the different textures are also presented.
15
Dimos, D., S. J. Lockwood, T. J. Garino, H. N. Al-Shareef, and R. W. Schwartz. "Integrated Decoupling Capacitors using Pb(Zr,Ti)O3 Thin Films." MRS Proceedings 433 (1996). http://dx.doi.org/10.1557/proc-433-305.
Full textAbstract:
AbstractThin-film decoupling capacitors based on ferroelectric (Pb,La)(Zr,Ti)O3 films are being developed for use in advanced packaging applications. The increased integration that can be achieved by replacing surface-mount capacitors should lead to decreased package volume and improved high-speed performance. For this application, chemical solution deposition is an appropriate fabrication technique since it is a low-cost, high-throughput process. The use of relatively thick Pt electrodes (˜1 μm) to minimize series resistance and inductance is a unique aspect to fabricating these devices. In addition, the important electrical properties are discussed, with particular emphasis on lifetime measurements, which suggest that resistance degradation will not be a severe limitation on device performance. Finally, some of the work being done to develop methods of integrating these thin-film capacitors with ICs and MCMs is presented.
16
Dohya, Akihiro, Ikushi Morisaki, Manabu Bonkohara, and Hirofumi Nakamura. "Mcm Development Using Fine Pitch Ball Bump." MRS Proceedings 445 (1996). http://dx.doi.org/10.1557/proc-445-83.
Full textAbstract:
AbstractA fine-pitch ( less than 100 micro-meter pads pitch ) aluminum pad flip chip assembly technology for use with the built-up Printed Wiring Boards (PWB) has been developed and named “Lead-Less-Chip Assembly (LLC Assembly)” technology. Our newly developed technology consists of three points: Forming gold-ball-bumps on the aluminum pads of the bare LSI chip by a wire ball bonding method. Solder-coating on the copper pads of the built-up PWB using Micro Punching technology or the Super-Juffit technology. Flux-less solder bonding the bare chip onto the PWB with a nitrogen atmosphere.A reliability evaluation performed on a single chip and multi chip modules assembled using this LLC Assembly technology with test chips and real C-MOS devices showed a high level of endurance. We have applied this technology to Multichip modules (MCMs) for Note Personal Computers and portable terminals.
17
Guidotti, Ronald A., David J. Irvin, William R. Even, and Karl Gross. "Preparation and Characterization of Tin/Carbon Composites for Lithium-Ion Cells." MRS Proceedings 730 (2002). http://dx.doi.org/10.1557/proc-730-v1.11.
Full textAbstract:
AbstractA number of Sn/C composites were prepared for evaluation as anode materials for Li-ion cells. In one case, samples were prepared by incorporation of Sn species into organic precursors that were then pyrolyzed under an Ar/H2 cover gas to prepare the Sn/C composites. They were also prepared by decoration of various types of carbon with nanoparticles of Sn by electroless deposition using hydrazine. The carbons examined included a disordered carbon prepared in house from poly(methacrylonitrile), a mesocarbon microbead (MCMB) carbon, and a platelet graphite. The Sn/C composites were examined by x-ray diffraction (XRD) and scanning electron microscopy (SEM) and were also analyzed for Sn content. They were then tested as anodes in three-electrode cells against Li metal using 1M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC) solution. The best overall electrochemical performance was obtained with a Sn/C composite made by electroless deposition of 10% Sn onto platelet graphite.
18
Brown, W. D., H. A. Naseem, A. P. Malshe, J. H. Glezen, and W. D. Hinshaw. "Metallization Systems on Cvd-Diamond Substrates for Application in Multichip Modules." MRS Proceedings 391 (1995). http://dx.doi.org/10.1557/proc-391-59.
Full textAbstract:
AbstractBecause of its high thermal conductivity, free-standing CVD-diamond is an extremely attractive material for application as the substrate in multichip modules (MCMs). However, this material does present some technological challenges, one being the development of reliable metallization systems. In this work, adherent metallization systems, such as Au/Ti, Au/Ti-W, Au/Ni-Cr, Au/Cr and Cu/Cr have been produced at low temperatures. Thin adhesion/seed metal layers were deposited using sputtering and evaporation techniques. Gold and copper metallization of several microns thickness was accomplished by electroplating over the thin metal layer. Post-deposition annealing of both the adhesion/seed layer and plated metallization systems were performed at temperatures up to 500°C in an effort to enhance adhesion and determine the impact of subsequent high temperature operations on reliability issues such as intermetallic diffusion, delamination, and the impact of surface microcavities. Extremely adherent Au/Cr and Cu/Cr metallization systems appropriate for use in MCM technology were developed.
19
Lada, W., A. Deptula, B. Sartowska, T. Olczak, A. G. Cimielewski, M. Carewska, S. Scaccia, E. Simonetti, L. Giorgi, and A. Moreno. "Preparation and Characterization of LiCoO2 and LiMg0.05Co0.95O2 Thin Films on Porous Ni/NiO Cathodes for MCFC by Complex Sol-Gel Process (CSGP)." MRS Proceedings 623 (2000). http://dx.doi.org/10.1557/proc-623-395.
Full textAbstract:
AbstractThe major disadvantage of Ni/NiO cathodes for a Molten Carbonate Fuel Cells (MCFC) application is dissolution of NiO in K/Li electrolyte that significantly decreases the cell lifetime. Thin films of LiCoO2 or LiMg0.05Co0.9502 were prepared on a cathode body in order to protect them against dissolution. For preparation of starting sols the Complex Sol-Gel Process (CSGP) has been applied. These sols have been prepared by adding of LiOH to aq. acetates solution of Co 2+(Mg2+) with ascorbic acid and then by alkalizing them with aqueous ammonia to pH=8. The cathode plates of various dimensions (to several hundreds cm2) have been dipped in these sols and withdrawn at rate a 1.7 cm/s. Commercially sintered Ni plates were always initially oxidized by heating at various temperatures. Their microstructure and mechanical properties as a function of temperature were observed. Heat treatment should be carried out under the dead load of the ceramic plates in order to avoid their waving. The best non-folded plates were obtained by treating them for lh at 550°C. The covered substrates were calcined for lh at 650°C, using low heating ratel°C/min. The presence of LiCoO2 in a deposited coating has been proved by EDS patterns. The resultant film thicknesses were measured by scanning electron microscopy (SEM) on the fractured cross-sections; they ranged from 0.5 to 2νm and depended on sol concentration and viscosity. A 350 hundred hours test in molten carbonates, proved that the cathode bodies covered with LiCoO2 are completely prevented from dissolution of Ni in a molten K/Li electrolyte. Dissolution of LiCoO2 coating was not observed as well. After treatment in a molten electrolyte SEM observations did not show any changes in microstructures and morphology of the covered cathodes.