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排序方式: 共有134条查询结果,搜索用时 15 毫秒
1.
Marcella Bonchio Mauro Carraro Martino Gardan Gianfranco Scorrano Enrico Drioli Enrica Fontananova 《Topics in Catalysis》2006,40(1-4):133-140
The incorporation of decatungstate in polymeric membranes provides new heterogeneous photocatalysts for the oxidation of organic
substrates under oxygen atmosphere at 25 °C. Photocatalytic membranes have been prepared yielding polymeric films with a high
thermal, chemical and mechanical stability (PVDF, PDMS, Hyflon). Surface spectroscopy techniques including transmittance and
reflectance UV-Vis and FT-IR have been used to assess the photocatalyst integrity within the polymeric support. Catalyst screening
has been performed under both homogeneous and heterogeneous photooxygenation conditions. The photocatalyst activity has been
evaluated in terms of the substrate conversion, turnover numbers, and recycling experiments. A membrane induced selectivity
behavior has been evidenced by comparison with homogeneous oxidations. 相似文献
2.
Bioinspired Synthesis of CaCO3 Superstructures through a Novel Hydrogel Composite Membranes Mineralization Platform: A Comprehensive View 下载免费PDF全文
3.
An alternative procedure for drought risk assessment and for the mitigation of drought risk is proposed in the paper. An analysis
of the relationship between failure of water supply systems and reservoir volumes for the urban area of Firenze in central
Tuscany, in central Italy, is performed. Long term simulations are carried out using the software package WEAP. A simplified
model of the water resources system is built to assess the threshold values and the management rules. The probability to have
definite degree of shortage in the water supply system is evaluated in function of the volume stored in the reservoir at the
beginning of the month with Monte Carlo simulations. The reservoir levels and volumes are simulated using time series of the
period 1970–2005. Four scenarios (i.e. normal, pre-alert, alert and emergency) associated with different levels of severity
of drought are defined. Threshold values are identified considering the probability to assure a given fraction of the demand
in a certain time horizon, and are calibrated with an optimization method, which try to minimize the water shortages, especially
the heavier. The critical situations are assessed month by month in order to evaluate optimal management rules during the
year and avoid conditions of total water shortage. 相似文献
4.
We present a decidability result for the model checking of a certain class of properties that can be conveniently expressed
as ground formulae of a first-order temporal fragment. The decidability result is obtained by importing into the context of
model-checking problems some techniques developed for the combination of decision procedures for the satisfiability of constraints.
The general decidability result is then specialized for checking properties of particular interest, such as liveness and safety,
and, for the latter case, a more optimized algorithm has been proposed. 相似文献
5.
Francesco Baino Giulia Magnaterra Elisa Fiume Alessandro Schiavi Luciana-Patricia Tofan Martin Schwentenwein Enrica Verné 《Journal of the American Ceramic Society》2022,105(3):1648-1657
This work deals with the additive manufacturing and characterization of hydroxyapatite scaffolds mimicking the trabecular architecture of cancellous bone. A novel approach was proposed relying on stereolithographic technology, which builds foam-like ceramic scaffolds by using three-dimensional (3D) micro-tomographic reconstructions of polymeric sponges as virtual templates for the manufacturing process. The layer-by-layer fabrication process involves the selective polymerization of a photocurable resin in which hydroxyapatite particles are homogeneously dispersed. Irradiation is performed by a dynamic mask that projects blue light onto the slurry. After sintering, highly-porous hydroxyapatite scaffolds (total porosity ~0.80, pore size 100-800 µm) replicating the 3D open-cell architecture of the polymeric template as well as spongy bone were obtained. Intrinsic permeability of scaffolds was determined by measuring laminar airflow alternating pressure wave drops and was found to be within 0.75-1.74 × 10−9 m2, which is comparable to the range of human cancellous bone. Compressive tests were also carried out in order to determine the strength (~1.60 MPa), elastic modulus (~513 MPa) and Weibull modulus (m = 2.2) of the scaffolds. Overall, the fabrication strategy used to print hydroxyapatite scaffolds (tomographic imaging combined with digital mirror device [DMD]-based stereolithography) shows great promise for the development of porous bioceramics with bone-like architecture and mass transport properties. 相似文献
6.
7.
Chiara Vitale-Brovarone Francesco Baino Oana Bretcanu Enrica Verné 《Journal of materials science. Materials in medicine》2009,20(11):2197-2205
Glass–ceramic scaffolds mimicking the structure of cancellous bone were produced via sponge replication technique by using
a polyurethane foam as template and glass powder below 30 μm as inorganic phase. Specifically, a SiO2-based glass of complex composition and its corresponding P2O5-based “specular” glass were used as materials for scaffolding. The polymeric sponge was thermally removed and the glass powders
were sintered to obtain a replica of the template structure. The scaffolds were investigated and compared from a structural,
morphological and mechanical viewpoint by assessing their crystalline phases, volumetric shrinkage, pores content and interconnection,
mechanical strength. In addition, the scaffolds were soaked in acellular simulated body fluid to investigate their in vitro
behaviour. The produced scaffolds have a great potential for bone reconstructive surgery because their features, such as shape,
strength, bioactivity and bioresorption, can be easily tailored according to the end use. 相似文献
8.
The surface tension and the density of some gold alloys have been measured and their wetting behaviour investigated in relation to different ceramic supports. Relationships between surface tension and density as a function of temperature are proposed. 相似文献
9.
Giulietta Smulevich Enrica Droghetti Claudia Focardi Massimo Coletta Chiara Ciaccio Mila Nocentini 《Food chemistry》2007,101(3):1071-1077
Carbon monoxide (CO) can be used to treat fresh meat and fish in order to retain its ‘fresh’ red colour appearance for a longer period of time. In fact, upon aging, myoglobin is oxidized to met-myoglobin with the concomitant blue-shift and broadening of the Soret maximum, which brings about a change in the colour of the fish, revealing that it is no longer fresh. The use of carbon monoxide, which reacts with the oxy-myoglobin to form a fairly stable cherry red carboxy-myoglobin complex may mask spoilage, because the CO-complex can be stable beyond the microbiological shelf life of the meat. The presence of CO in tuna fish has been investigated by optical spectroscopy as the formation of the CO adduct can be easily detected by the combined analysis of electronic absorption spectra in their normal and second derivative modes, monitoring the intense Soret band at 420 nm. The presence of met- and oxy-myoglobin can obscure the presence of small amounts of the CO adduct; however, it can be revealed by chemically reducing the met- and oxy-forms to the deoxy-form in an anaerobic environment. This spectroscopic method provides a qualitatively rapid laboratory screening procedure for food control to unmask the presence of CO in frozen or fresh fish. 相似文献
10.
Stevenson Harold W.; Parker Timothy; Wilkinson Alexander; Hegion Ada; Fish Enrica 《Canadian Metallurgical Quarterly》1976,68(4):377
Assessed the effectiveness of a battery of commonly used cognitive and psychometric tasks in predicting achievement in reading and arithmetic in Grades 1-3. Tasks were administered to 255 children (mean age, 5.4 yrs) prior to kindergarten. Teachers' ratings were obtained in kindergarten. Combinations of 4 tasks yielded optimal predictions of achievement. More effective prediction could be made from prekindergarten tasks than from teachers' ratings. After Grade 1, the most effective prediction was derived from scores on prior tests of achievement. Relations among various tests of achievement both within and across years and the relation of achievement scores to age, IQ, and parental education were determined. Predictive tasks and teachers' ratings were used to select children who later had difficulty in school. Caution is urged, however, in using prekindergarten tasks to identify children who need extra help. Because prediction is imperfect, such tasks ought not to be used to assign children to special groups. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献