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排序方式: 共有429条查询结果,搜索用时 31 毫秒
41.
R. A. Jasso-Terán D. A. Cortés-Hernández E. M. Múzquiz-Ramos H. J. Sánchez-Fuentes 《Journal of materials science. Materials in medicine》2014,25(10):2221-2228
In this work, Zn(1?x)CaxFe2O4 nanoparticles (x = 0, 0.5 and 1) have been synthesized by sol–gel method followed by heat treatment at a temperature within the range of 300–700 °C. The samples with appropriate saturation magnetization (Ms), low coercivity and remanence were Zn0Ca1Fe2O4 treated at 300 °C (Ms ~ 25 emu/g), Zn0Ca1Fe2O4 treated at 400 °C (Ms ~ 40 emu/g) and Zn0.50Ca0.50Fe2O4 treated at 400 °C (Ms ~ 31 emu/g). These samples were analyzed by scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and transmission electron microscopy. The heating ability of selected nanoparticles was evaluated under a magnetic field using a solid state induction heating equipment. The obtained nanoferrites showed a particle size within the range of 13–14 nm. The Zn0Ca1Fe2O4 treated at 400 °C was able to heat the nanoferrite particles/water suspension (10 mg/2 ml) at a temperature of 44 °C under the selected magnetic field (10.2 kA/m and frequency 362 kHz). Additionally, in vitro bioactivity assessment was performed by immersing samples in a simulated body fluid for different periods of time at physiological conditions of pH and temperature. The samples showed an appropriate bioactivity. These nanoferrites are highly potential materials for hyperthermia treatment. 相似文献
42.
Since 2006 a European map of indoor radon (Rn) concentration is in the making. So far 20 countries have contributed with national data, allowing a fair coverage of parts of Europe. This paper presents the current (September 2010) state of the map, discusses its rationale, presents some statistical findings and addresses a few problems which arose during the work. It also briefly presents the European Atlas of Natural Radiation project, of which the Rn map will be part, and further, planned maps of environmental natural radioactivity. 相似文献
43.
L Arreguín Osuna R García Caballero MT Montero Cortés I Ortiz Aldana 《Canadian Metallurgical Quarterly》1998,45(3):7-11
OBJECTIVE: To compare the efficacy and safety of levocabastine nasal spray asid cetirizine oral for the treatment of perennial allergic rhinitis in children. MATERIAL AND METHODS: In this randomized, prospective experimental, open clinical trial. We studied 30 children with ages between 6 and 16 years with perennial allergic rhinitis. Group 1, 17 subjects (7 female, 10 male) received cetirizine once daily, 5 mg children weientig less dian 30 k asid 10 mg in children weighing more trw' 30 k during 15 days. Group 2, 13 subjects (7 male, 6 female) received levocabastine 2 puffs BID on each nostril during tbe same time. A nasal symptoms score, nasal peal: flow vid eosinophils in a nasal smear were performed before and after treatment. RESULTS: There were no statistical differences in age, weight, height and arid duration of symptoms. Both groups showed improvement of symptoms via nasal peak flow with no differences between them (intergroup); nasal eosinophils remained unchanged. We for third statistical differences pre vid postreatment in each group (intragroup): Group 1, nasal congestion p = 0.002, ocular itch p = 0.01, sneezing p = 0.007, nasal secretion p = 0.01, nasal itch O = 0.009, total points O = 0.0005. Group 2, nasal congestion O = 0.02, ocular itch p = 0.05, sneezing p = 0.01, nasal secretion p = 0.01, nasal itch p = 0.04, total points p = 0.005. Significant differences were found in nasal peal' flow in Group 1 (p = 0.01) but no differences in eosinophils between file two groups. Side effects: 3 subjects in Group 1 (drowsiness, 1 appetite increase said 1 rhinorrea with epistaxis) vide 1 in Group 2 sensation of facial edema. CONCLUSION: Bofil drugs are effective the clinical relief of symptoms of perennial allergic rhinitis in children vied levocabastine has less side effects. 相似文献
44.
Esteban López-Salinas M. Elena Llanos Serrano M. Antonia Cortés Jácome Isaac Schifter Secora 《Journal of Porous Materials》1995,2(4):291-297
A lamellar hydrocalumite-type [Ca2Al(OH)6]NO3·mH2O, (HC), was synthesized and characterized by X-ray diffraction analysis (XRD), surface area, pore size measurements, CO2-Thermal Programmed Desorption, and later tested as catalysts in the double bond isomerization of 1-butene. The layered structure of HC collapses above 523 K yielding an amorphous material at 573 K which upon calcination at 873–973 K transforms into a mixture of CaO and mayenite Ca12Al14O33. The calcination temperature has a marked effect in the formation of basic sites. Thus for example, HC calcined at 1073 K shows 90% of strong basic sites (CO2 desorption at 1023 K) while they are absent in HC calcined at 573–673 K. HC calcined at 973 K shows high catalytic activity (74% conversion) in the isomerization of 1-butene without any appreciable deactivation after 4 h on stream. 相似文献
45.
46.
K Luzuriaga Y Bryson G McSherry J Robinson B Stechenberg G Scott M Lamson S Cort JL Sullivan 《Canadian Metallurgical Quarterly》1996,174(4):713-721
The challenge of useful serial photographic documentation of hair loss can be met by using a regimented approach at each photographic session. Patient outcomes that are better documented allow for more informed decisions to be made about the course of therapy by both the physician and the patient. 相似文献
47.
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49.
Anastasio MA Zhang J Pan X Zou Y Ku G Wang LV 《IEEE transactions on medical imaging》2005,24(2):199-210
Thermoacoustic tomography (TAT) is an emerging imaging technique with great potential for a wide range of biomedical imaging applications. In this paper, we propose and investigate reconstruction approaches for TAT that are based on the half-time reflectivity tomography paradigm. We reveal that half-time reconstruction approaches permit for the explicit control of statistically complementary information that can result in the optimal reduction of image variances. We also show that half-time reconstruction approaches can mitigate image artifacts due to heterogeneous acoustic properties of an object. Reconstructed images and numerical results produced from simulated and experimental TAT measurement data are employed to demonstrate these effects. 相似文献
50.
Carlos?A.?Coello?CoelloEmail author Nareli?Cruz?Cortés 《Genetic Programming and Evolvable Machines》2005,6(2):163-190
In this paper, we propose an algorithm based on the clonal selection principle to solve multiobjective optimization problems (either constrained or unconstrained). The proposed approach uses Pareto dominance and feasibility to identify solutions that deserve to be cloned, and uses two types of mutation: uniform mutation is applied to the clones produced and non-uniform mutation is applied to the not so good antibodies (which are represented by binary strings that encode the decision variables of the problem to be solved). We also use a secondary (or external) population that stores the nondominated solutions found along the search process. Such secondary population constitutes the elitist mechanism of our approach and it allows it to move towards the true Pareto front of a problem over time. Our approach is compared with three other algorithms that are representative of the state-of-the-art in evolutionary multiobjective optimization. For our comparative study, three metrics are adopted and graphical comparisons with respect to the true Pareto front of each problem are also included. Results indicate that the proposed approach is a viable alternative to solve multiobjective optimization problems. 相似文献