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81.
Inorganic ligand-modified, colloid-enhanced ultrafiltration (ILM-CEUF) is as a novel membrane-based separation method for selectively removing target ions from aqueous solution. Traditional colloid-enhanced ultrafiltration (CEUF) is a well-established membrane-based separation technique that can be used to separate metal ions from other aqueous solution components. Ligand-modified, colloid-enhanced ultrafiltration (LM-CEUF) uses organic ligands that selectively complex target ions and also associate with a water-soluble colloid, such as a surfactant micelle or polyelectrolyte. The colloid, associated -ligand, and target ion are then concentrated using an ultrafilter, producing a filtrate with a low concentration of the target ion. While traditional LM-CEUF techniques are able to provide quantitative separations of a variety of ionic pollutants, the high costs of the chelating agents make such techniques nonviable in most remediation schemes. This study investigated the replacement of organic ligands with carbonate for the selective removal of U(VI) from aqueous solution.In slightly to moderately basic solutions containing carbonate, UO2(CO3)34− can be made to dominate the U(VI) speciation. Using poly(diallyldimethylammonium) chloride, the effectiveness and efficiency of ILM-CEUF for removing U(VI) from other aqueous solution components was investigated as a function of carbonate concentration, pH, and ionic strength. Uranium separations of greater than 99.6% were achieved; even in the presence of large excesses of competing ions. The specific separation of U(VI) from Sr2+ was also examined. 相似文献
82.
Apurv Dash Jürgen Malzbender Robert Vaßen Olivier Guillon Jesus Gonzalez-Julian 《Journal of the American Ceramic Society》2020,103(12):7072-7081
The compressive creep of silicon carbide fiber reinforced Ti3SiC2 MAX phase with both fine and coarse microstructure was investigated in the temperature range of 1000-1300°C. Comparison of only steady-state creep was done to understand the response of fabricated composite materials toward creep deformation. It was demonstrated that the fibers are more effective in reducing the creep rates for the coarse microstructure by an increase in activation energy compared to the variant with a finer microstructure, being partly a result of the enhanced creep rates for the microstructure with larger grain size. Grain boundary sliding along with fiber fracture appears to be the main creep mechanism for most of the tested temperature range. However, there are indications for a changed creep mechanism for the fine microstructure for the lowest testing temperature. Local pores are formed to accommodate differences in strain related to creeping matrix and predominantly elastically deformed fibers during creep. Microstructural analysis was done on the material before and after creep to understand the deformation mechanics. 相似文献
83.
Ricardo Cambraia Parreira Diana Paola Gmez‐Mendoza Itamar Couto Guedes de Jesus Rafael Pereira Lemos Anderson Kennedy Santos Cristiana Perdigo Rezende Henrique Csar Pereira Figueiredo Mauro Cunha Xavier Pinto Frank Kjeldsen Silvia Guatimosim Rodrigo Ribeiro Resende Thiago Verano‐Braga 《Proteomics. Clinical applications》2020,14(4)
84.
E. Gemelli J. de Jesus N.H.A. Camargo G.D. de Almeida Soares V.A.R. Henriques F. Nery 《Materials science & engineering. C, Materials for biological applications》2012,32(4):1011-1015
A titanium-based composite with Ca-P phases was prepared in situ by powder metallurgy processing with TiH2 and nanometric β-TCP powders. Crystal phases of the as-fabricated composite are found to be α-Ti, CaTiO3 and TixPy phase(s). The TixPy and CaTiO3 phases resulted from the reaction between titanium and β-TCP at about 1135 °C. The composite presented a mean compressive strength of 635 MPa and a lower contact angle than pure titanium. 相似文献
85.
Luciana da Cunha Fernanda M. B. Coutinho Viviane G. Teixeira Edgar F. O. de Jesus Ailton S. Gomes 《Polymer Bulletin》2008,61(3):319-330
Polyacrylamide chains were grafted onto styrene-divinylbenzene (S-DVB) copolymer beads using gamma
radiation from a 60Co source by applying the simultaneous method. S-DVB macroporous
copolymer was synthesized by aqueous suspension polymerization and characterized by determining apparent
density, surface area, pore volume distribution and water uptake. Optical and electron microscopies
were used in order to observe the copolymer morphology. The effect of parameters such as monomers concentration,
irradiation dose and presence of inhibitor (Mohr’s salt) on grafting reaction was studied. The grafting
reaction was evaluated with the aid of elemental analysis, FTIR, HR-MAS NMR spectrometry, thermogravimetry
(TG) and electron microscopy. Grafting yield (evaluated by nitrogen content) increased with acrylamide
concentration and irradiation dose increasing. However, above determined values of those parameters
it is observed a tendency of decreasing on the grafting yield. The presence of Mohr’s salt inhibited
the production of homopolymer as well as the progress of the grafting reaction. 相似文献
86.
R. Mateus A. P. Jesus B. Braizinha J. Cruz J. V. Pinto J. P. Ribeiro 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2002,190(1-4):117-121
A method for proton-induced γ-ray analysis (PIGE) of Li (either elemental or isotopic composition) in thick samples is presented in this work, which is based on a code that integrates the nuclear reaction excitation function, measured at the same experimental conditions, along the depth of the sample. The energy steps needed to define accurately the excitation function are used as energy intervals for the integration procedure. The excitation function and cross-sections of the reaction 7Li(p,p′γ)7Li, for protons in the energy range 0.60–2.5 MeV, were obtained and used as input to calculate lithium concentrations in thick and intermediate samples. The calculated thick target yields of samples with several amounts of lithium were compared with the respective measured yields, showing that this is a reliable and accurate method for PIGE analysis of Li in thick samples. 相似文献
87.
Sintered nanoscale silver is a promising interconnection material for semiconductor devices because it provides improved joint properties compared with solder and wire bonds. It has higher electrical and thermal conductivity and is capable of higher operating temperature. Joints with die shear strength above 20 MPa can be formed at around 250°C even without applied pressure. Sintered silver joints were also found to be an order of magnitude more reliable than solder joints and wire bonds. In this work, the electromigration behavior of sintered nanosilver material under conditions of high applied current density and elevated temperature was investigated. Thin strips of sintered nanosilver formed on ceramic substrates were tested under current densities exceeding 150 kA/cm2 at temperatures of 150°C and above. Results based on the percentage change in sample resistance showed that the sintered silver lasted at least ten times longer than aluminum wire bonds. Examination of failed strips revealed that hairline cracks formed during sintering were the main cause of failure. Otherwise, defect-free samples exhibited a 10-fold increase in lifetime over wire bonds under similar conditions. 相似文献
88.
Patrícia ValderramaRonei Jesus Poppi 《Chemometrics and Intelligent Laboratory Systems》2011,106(2):160-165
The second order standard addition method and spectrofluorimetry were used for determination of ibuprofen enantiomers in human plasma and urine. The methodology was based on chiral recognition of ibuprofen by formation of an inclusion complex with a chiral auxiliary, β-cyclodextrin, in the presence of 1-butanol. The strategy combines the use of PARAFAC, for extraction of the pure analyte signal, with the standard addition method, for determinations in presence of a matrix effect. A specific PARAFAC model was built for each sample and the scores were related to (S)-ibuprofen concentration using a linear regression in the standard addition method. Feasible results were obtained for determinations in the molar fraction range from 50 to 80% of (S)-ibuprofen, providing absolute errors lowers than 4.0% for plasma and urine. 相似文献
89.
Maria I. Morales-Lozano Paula Rodriguez-Otero Lidia Sancho Jorge M. Nuez-Cordoba Elena Prieto Maria Marcos-Jubilar Juan J. Rosales Ana Alfonso Edgar F. Guillen Jesus San-Miguel Maria J. Garcia-Velloso 《International journal of molecular sciences》2022,23(17)
Multiple myeloma (MM) is the second most common haematological malignancy and remains incurable despite therapeutic advances. 18F-FDG (FDG) PET/CT is a relevant tool MM for staging and it is the reference imaging technique for treatment evaluation. However, it has limitations, and investigation of other PET tracers is required. Preliminary results with L-methyl-[11C]- methionine (MET), suggest higher sensitivity than 18F-FDG. This study aimed to compare the diagnostic accuracy and prognostic value of 1FDG and MET in MM patients. We prospectively compared FDG and MET PET/CT for assessment of bone disease and extramedullary disease (EMD) in a series of 52 consecutive patients (8 smoldering MM, 18 newly diagnosed MM and 26 relapsed MM patients). Bone marrow (BM) uptake patterns and the detection of focal lesions (FLs) and EMD were compared. Furthermore, FDG PET parameters with known MM prognostic value were explored for both tracers, as well as total lesion MET uptake (TLMU). Median patient age was 61 years (range, 37–83 years), 54% were male, 13% of them were in stage ISS (International Staging System) III, and 31% had high-risk cytogenetics. FDG PET/CT did not detect active disease in 6 patients, while they were shown to be positive by MET PET/CT. Additionally, MET PET/CT identified a higher number of FLs than FDG in more than half of the patients (63%). For prognostication we focussed on the relapsed cohort, due to the low number of progressions in the two other cohorts. Upon using FDG PET/CT in relapsed patients, the presence of more than 3 FLs (HR 4.61, p = 0.056), more than 10 FLs (HR 5.65, p = 0.013), total metabolic tumor volume (TMTV) p50 (HR 4.91, p = 0.049) or TMTV p75 (HR 5.32, p = 0.016) were associated with adverse prognosis. In MET PET/CT analysis, TMTV p50 (HR 4.71, p = 0.056), TMTV p75 (HR 6.27, p = 0.007), TLMU p50 (HR 8.8, p = 0.04) and TLMU p75 (HR 6.3, p = 0.007) adversely affected PFS. This study confirmed the diagnostic and prognostic value of FDG in MM. In addition, it highlights that MET has higher sensitivity than FDG PET/CT for detection of myeloma lesions, including FLs. Moreover, we show, for the first time, the prognostic value of TMTV and TLMU MET PET/CT in the imaging evaluation of MM patients. 相似文献
90.
Carlos Aguilar‐Ibañez Julio A. Mendoza‐Mendoza Juan C. Martinez Jose de Jesus Rubio Miguel S. Suarez‐Castanon 《国际强度与非线性控制杂志
》2015,25(12):1739-1750
》2015,25(12):1739-1750
A solution to the stabilization problem of a compact set by means of the Interconnection and Damping Assignment Passivity‐Based Control methodology, for an affine nonlinear system, was introduced. To this end, we expressed the closed‐loop system as a Port Hamiltonian system, having the property of almost all their trajectories asymptotically converge to a convenient limit set, except for a set of measure zero. It was carried out by solving a partial differential equation (PDE) or single matching condition, which allows the desired energy level or limit set E to be shaped explicitly. The control strategy was tested using the magnetic beam balance system and the pendulum actuated by a direct current motor (DC‐motor), having obtained satisfactory results. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献