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Photocatalytic properties of PMMA‐TiO2 class I and class II hybrid nanofibers obtained by electrospinning
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Federico Ohlmaier‐Delgadillo Maria Monica Castillo‐Ortega Rafael Ramírez‐Bon Lorena Armenta‐Villegas Dora Evelia Rodríguez‐Félix Hisila Santacruz‐ Ortega Teresa del Castillo‐Castro Irela Santos‐Sauceda 《应用聚合物科学杂志》2016,133(48)
The preparation, characterization, and photocatalytic activity evaluation of three hybrid fibrous materials composed mainly by poly(methyl methacrylate) (PMMA), methyl methacrylate (MMA): 3‐(trimethoxysilyl) propyl methacrylate (TMSPM): titanium butoxide (TBT), TiO2 nanoparticles (NPTiO2), and TiO2 nanowires (NWTiO2) is studied. Two types of fibe?s structures were prepared, single and core‐shell structures. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showed both structures, single and core‐shell, as well as the inorganic phase were dispersed in the hybrid fibers. Infrared spectroscopic analysis (FT‐IR) and thermal analysis showed the organic and inorganic components, as well as the weight percentage of the inorganic phase present in hybrid fibers. The photocatalytic activity of the hybrid fibers class I and II showed that the best photodegradative efficiency for methylene blue in aqueous solution (2.9 × 10?5 M) was 95%, provided by PMMA—10 wt % NPTiO2. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44334. 相似文献
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A.L. Herrera-May P.J. García-Ramírez L.A. Aguilera-Cortés E. Figueras J. Martinez-Castillo E. Manjarrez A. Sauceda L. García-González R. Juárez-Aguirre 《Sensors and actuators. A, Physical》2011,165(2):399-409
A resonant magnetic field microsensor based on Microelectromechanical Systems (MEMS) technology including a piezoresistive detection system has been designed, fabricated, and characterized. The mechanical design for the microsensor includes a symmetrical resonant structure integrated into a seesaw rectangular loop (700 μm × 450 μm) of 5 μm thick silicon beams. An analytical model for estimating the first resonant frequency and deflections of the resonant structure by means of Rayleigh and Macaulay's methods is developed. The microsensor exploits the Lorentz force and presents a linear response in the weak magnetic field range (40–2000 μT). It has a resonant frequency of 22.99 kHz, a sensitivity of 1.94 V T?1, a quality factor of 96.6 at atmospheric pressure, and a resolution close to 43 nT for a frequency difference of 1 Hz. In addition, the microsensor has a compact structure, requires simple signal processing, has low power consumption (16 mW), as well as an uncomplicated fabrication process. This microsensor could be useful in applications such as the automotive sector, the telecommunications industry, in consumer electronic products, and in some medical applications. 相似文献
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V Baca C Lavalle R García T Catalán JM Sauceda G Sánchez I Martínez ML Ramírez LM Márquez JC Rojas 《Canadian Metallurgical Quarterly》1999,26(2):432-439
OBJECTIVE: To evaluate the effect of intravenous methylprednisolone (IVMP) and cyclophosphamide (IVCy) in children with severe neuropsychiatric (NP) systemic lupus erythematosus (NPSLE). METHODS: We studied 7 consecutive pediatric patients with severe NPSLE. All patients were treated initially with IVMP and IVCy followed by monthly IVCy for at least 3 months, and then every 2 and/or 3 months according to clinical response. Prednisone was given at 1-2 mg/kg during the first month. Laboratory studies included routine laboratory tests, antinuclear antibodies, anti-dsDNA, antiphospholipid antibodies, and complement components C3 and C4. Neurodiagnostic studies included cerebrospinal fluid, magnetic resonance imaging, computed tomography scanning, single photon emission computed tomography and electroencephalography. RESULTS: Three patients had organic brain syndrome with psychosis, 3 had seizures, 1 stroke, 1 cerebral vasculitis, 1 optic neuritis, and 1 transverse myelitis. In 3 of these cases, nervous system involvement was the initial presentation of SLE. Five patients had 2 or more NP manifestations. Most of them were accompanied by general SLE activity. Anticardiolipin antibodies were positive in 3 patients and none was anticoagulated. All patients improved, 6 patients had a complete recovery and 1 patient recovered with minor neurological deficit. All but one improved significantly within the first week of combined IVMP and IVCy. The mean time of follow-up was 37 months (range 8-55). IVCy was well tolerated with minimal side effects. CONCLUSION: Early aggressive treatment with combined IVMP and IVCy followed by monthly IVCy may be an effective therapy for severe NPSLE in children. 相似文献
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Physicochemical characterization of actomyosin–paramyosin from giant squid mantle (Dosidicus gigas)
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Leandro García-González Julián Hernández-Torres Claudia Mendoza-Barrera Miguel Meléndez-Lira Pedro J. García-Ramírez Jaime Martínez-Castillo Ángel Sauceda Agustin L. Herrera-May Juan Muñoz Saldaña Francisco J. Espinoza-Beltrán 《Journal of Materials Engineering and Performance》2008,17(4):580-585
Ti-Si-N-O coatings were deposited on AISI D2 tool steel and silicon substrates by dc reactive magnetron co-sputtering using
a target of Ti-Si with a constant area ratio of 0.2. The substrate temperature was 400 °C and reactive atmosphere of nitrogen
and argon. For all samples, argon flow was maintained constant at 25 sccm, while the flow of the nitrogen was varied to analyze
the structural changes related to chemical composition and resistivity. According to results obtained by x-ray diffraction
and stoichiometry calculations by x-ray energy dispersive spectroscopy the Ti-Si-N-O coatings contain two solid solutions.
The higher crystalline part corresponds to titanium oxynitrure. Hardness tests on the coatings were carried out using the
indentation work model and the hardness value was determined. Finally, the values of hardness were corroborated by nanoindentation
test, and values of Young’s modulus and elastic recovery were discussed. We concluded that F2TSN sample (F
Ar = 25 sccm, F
N = 5 sccm, P = 200 W, and P
W = 8.9 × 10−3 mbar) presented the greatest hardness and the lowest resistivity values, due to its preferential crystalline orientation. 相似文献
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Using econometric analysis, this study provides empirical evidence to support a cause-and-effect relationship of managerial actions to financial performance in a post-ERP implementation stage. Senior information systems managers reveal the state of affairs, providing a snapshot reference during that time period. Financial figures were collected for firms who were matched to our survey instrument. Regression analysis establishes that increased technological competence affects net sales, relationships with outside experts affect earnings, return-on-assets and return-on-investment, top management support affects net sales and net income, long-range planning negatively affects earnings, and the sharing of information between departments affects net income, return-on-assets and return-on-investments. 相似文献
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Daniel Sauceda Nicolás Velázquez Octavio García-Valladares Ricardo Beltrán 《Journal of Mechanical Science and Technology》2011,25(6):1399-1408
In this work, a solar parabolic trough collector (PTC) has been dimensioned and its technical feasibility has been evaluated
in order to be used as ammonia direct vapor generator in an advanced absorption air-cooled Solar-GAX cycle of 10.6 kW cooling
capacity. A detailed numerical simulation model that takes into account the geometry and the optical, thermal and fluid dynamic
behavior of the PTC has been developed. The model has been solved in order to reach minimal thermal losses through the PTC,
and maximum coefficient of performance (COP) of the Solar-GAX cycle. Under design conditions, the solar PTC efficiency, the
COP of the Solar-GAX cycle and the global efficiency of the system were 0.62, 0.87 y and 0.54 respectively. The calculated
efficiency is 25.5 % higher than that provided by a single effect water-lithium bromide cycle coupled in an indirect form
with a solar PTC system. 相似文献
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Kothari S.C. Bishop Luke Sauceda Jeremias Daugherty Gary 《Software Quality Journal》2004,12(2):99-120
This paper presents a pattern-based framework for developing tool support to detect software anomalies. The use of a pattern-based approach is important because it provides the flexibility needed to address domain-specific needs, with respect to the types of problems the tools detect and the strategies used to inspect and adapt the code. Patterns can be used to detect a variety of problems, ranging from simple syntactic issues to difficult semantic problems requiring global analysis. Patterns can also be used to describe transformations of the software, used to rectify problems detected through software inspection, and to support interactive inspection and adaptation when full automation is impractical. This paper describes a part of the Knowledge Centric Software (KCS) framework that embodies the pattern-based approach and provides capabilities for addressing different languages and different application domains. While only the part of the framework relevant to code inspections is addressed in this paper, in future, we also expect to address UML analysis and design models. As an application of the research, we present an overview of an inspection tool being developed for high assurance software for avionics systems. 相似文献
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Ricardo Beltran Nicolas Velazquez Alma Cota Espericueta Daniel Sauceda Guillermo Perez 《Journal of Mechanical Science and Technology》2012,26(10):3311-3321
This paper presents a mathematical model that allows representing the optical behavior of a solar parabolic dish concentrator and the thermal performance of a cavity receiver. A procedure and a graphical method for the design of dish/cavity systems are proposed. A parametric study of the main geometric variables is performed and the influence of climate variables on the thermal behavior of the system coupled to a Stirling engine is analyzed. The model considers errors of solar collector, intercept factor, reflected and emitted radiation, conduction, and convection heat losses. For the validation of the model, the results obtained were compared with theoretical and experimental results reported in the literature. The calculation of the radiation losses, emitted and reflected from the receiver presented errors of up to 14%, and the average error for the rest of the thermal losses, interception factor and the absorber??s temperature, was less than 3%. These results show that the proposed model can be used with sufficient certainty to design and optimize solar dish collectors with cavity receivers. 相似文献
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