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排序方式: 共有352条查询结果,搜索用时 15 毫秒
91.
Marianna N. Xanthopoulou Elizabeth FragopoulouKonstantia Kalathara Tzortzis NomikosHaralabos C. Karantonis Smaragdi Antonopoulou 《Food chemistry》2010
Two commercially available Greek wines were treated with two different extraction methods in order to obtain either the total lipid fraction or several fractions containing different classes of phenolic compounds. 相似文献
92.
We examine the dynamic behaviour of unemployment rates by gender and of the gender unemployment gap over the 1992–2009 period by Italian regions. The results from unit root tests with unknown structural breaks indicate that the gender unemployment gap has narrowed in most cases. However, the pace of catching‐up and the dynamic behaviour characterizing the individual unemployment series differ substantially from one region to another. We comment on our results in the light of the reforms applied in the Italian labour market over the last two decades. 相似文献
93.
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95.
Safronova M Kozlov M Clark C 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2012,59(3):439-447
A review of recent theoretical calculations of blackbody radiation (BBR) shifts in optical atomic clocks is presented. We summarize previous results for monovalent ions that were obtained by a relativistic all-order single-double method, where all single and double excitations of the Dirac- Fock wave function are included to all orders of perturbation theory. A recently developed method for accurate calculations of BBR shifts in divalent atoms is then presented. This approach combines the relativistic all-order method and the configuration interaction method, which provides for accurate treatment of correlation corrections in atoms with two valence electrons. Calculations of the BBR shifts in B+, Al+, and In+ have enabled us to reduce the present fractional uncertainties in the frequencies of their clock transitions as measured at room temperature: to 4 × 10-19 for Al+ and 10-18 for B+ and In+. These uncertainties approach recent estimates of the limits of precision of currently proposed optical atomic clocks. We discuss directions of future theoretical developments for reducing clock uncertainties resulting from blackbody radiation shifts. 相似文献
96.
Marianna Garfí Laia Ferrer-Martí Ivet Ferrer 《Renewable & Sustainable Energy Reviews》2012,16(1):575-581
Low-cost household digesters are a promising appropriate technology which can help reducing the pressure on the environment due to deforestation and greenhouse gases emissions. The biogas and biofertilizer produced can alleviate poverty, by improving health conditions, increasing crops productivity and saving working time and burden for women and children. The aim of this study is to evaluate low-cost digesters technical, environmental and socio-economic impacts in rural communities of the Peruvian Andes, where a pilot project was developed during the last 3 years. Although the benefits are restricted by the performance of anaerobic digestion at high altitude, the results show that the digesters improve household living conditions and economy, while reducing environmental impacts. Biogas production covers around 60% of fuel needs for cooking, leading to 50-60% decrease in firewood consumption (i.e. deforestation) and greenhouse gases emissions; the annual income is increased by 3-5.5% due to fertilizer savings and potato sales. These values could be improved by enhancing digesters performance and the sustainability of the technology. 相似文献
97.
Veronica Ambrogi Witold Brostow Cosimo Carfagna Marianna Pannico Paola Persico 《Polymer Engineering and Science》2012,52(1):211-217
Uses of flexible poly(vinyl chloride) (PVC) are restricted by plasticizer migration affecting material properties. Moreover, the use of phthalate‐based plasticizers is being questioned worldwide because of their potential toxicity to humans and environment. Chemical modification of PVC structure is one of the most effective tools for reduction of plasticizer diffusion. In this work, a flexible dry blend based on cross‐linked PVC was obtained using a difunctional amine, namely isophoron diamine (IPDA) as the cross‐linking agent. The gel fraction was evaluated from insoluble portions obtained by means of solvent extraction; the efficiency of cross‐linking in reducing the plasticizer leaching was evaluated by migration tests. Effects of addition of IPDA on PVC thermal stability were determined by thermogravimetric analysis (TGA). The cross‐linking reaction turned out to be responsible for accelerating thermal degradation. Tribological properties of flexible uncross‐linked, cross‐linked and rigid PVC were determined. Flexible formulations were held in contact for 32 days with rigid PVC sheets. Plasticizer migration towards the interface caused an increase of dynamic friction compared to that of the reference rigid PVC.Vickers microhardness hVickers values of rigid PVC sheets decreased due to plasticizer surface absorption. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers 相似文献
98.
In this paper, we present a new mathematical method that synthesizes normal data sets for quantification of regional myocardium perfusion. In clinical practice, regional myocardial perfusion is often measured with a gamma camera and quantified via circumferential profile analysis. Normal reference profile data is used to increase the accuracy of the clinical interpretations. Our goal is to create reference data from an existing set of archived studies. An iterative mathematical method, based on two statistical hypotheses, was used to generate the study set instead of collecting normal examinations from a healthy population. Clinical validation is based on interpretations by six independent observers. Results of evaluation with synthesized normal data and its validation are presented. 相似文献
99.
Hyejoong Jeong Simona Ranallo Marianna Rossetti Jiwoong Heo Jooseok Shin Kwangyong Park Francesco Ricci Jinkee Hong 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(40):5572-5578
A method to control activation of a DNA nanodevice by supplying a complementary DNA (cDNA) strand from an electro‐responsive nanoplatform is reported. To develop functional nanoplatform, hexalayer nanofilm is precisely designed by layer‐by‐layer assembly technique based on electrostatic interaction with four kinds of materials: Hydrolyzed poly(β‐amino ester) can help cDNA release from the film. A cDNA is used as a key building block to activate DNA nanodevice. Reduced graphene oxides (rGOs) and the conductive polymer provide conductivity. In particular, rGOs efficiently incorporate a cDNA in the film via several interactions and act as a barrier. Depending on the types of applied electronic stimuli (reductive and oxidative potentials), a cDNA released from the electrode can quantitatively control the activation of DNA nanodevice. From this report, a new system is successfully demonstrated to precisely control DNA release on demand. By applying more advanced form of DNA‐based nanodevices into multilayer system, the electro‐responsive nanoplatform will expand the availability of DNA nanotechnology allowing its improved application in areas such as diagnosis, biosensing, bioimaging, and drug delivery. 相似文献
100.
We present a non-covalent compatibilization approach to prepare polypropylene (PP) composites containing expanded graphite (EG) and graphene nanoplatelets (GNPs) by melt compounding. This method involves PP matrix functionalization with pyridine (Py) moieties, which are capable of engaging in π-π interactions with the surface of the EG and GNPs. The addition of 10 wt% of PP grafted with amino-pyridine (PP-g-Py) to neat PP facilitated the break-up of EG particles, by intercalating between their layers and facilitating their separation into smaller tactoids. GNPs were prepared starting from EG through a thermomechanical exfoliation method. Addition of GNPs to PP resulted in well-dispersed platelets having aspect ratios as high as 40, whereas in the presence of the PP-g-Py compatibilizer the matrix contained sub-micron scale platelets. The electrical percolation thresholds were in the vicinity of 6 and 10 vol% in the compatibilized PP-EG and PP-GNP composites, respectively, and the maximum value of the electrical conductivity achieved was 10−1 S/m for the compatibilized GNP composites. Addition of GNPs resulted in increases in the flexural moduli by as much as 95% compared to the unfilled PP, whereas the impact strength remained unaffected up to 10 wt% GNP content. 相似文献