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排序方式: 共有135条查询结果,搜索用时 15 毫秒
91.
Kai Xiao Paolo Giusto Fengxiang Chen Ruotian Chen Tobias Heil Shaowen Cao Lu Chen Fengtao Fan Lei Jiang 《国家科学评论(英文版)》2021,8(8)
Light-driven ion (proton) transport is a crucial process both for photosynthesis of green plants and solar energy harvesting of some archaea. Here, we describe use of a TiO2/C3N4 semiconductor heterojunction nanotube membrane to realize similar light-driven directional ion transport performance to that of biological systems. This heterojunction system can be fabricated by two simple deposition steps. Under unilateral illumination, the TiO2/C3N4 heterojunction nanotube membrane can generate a photocurrent of about 9 μA/cm2, corresponding to a pumping stream of ∼5500 ions per second per nanotube. By changing the position of TiO2 and C3N4, a reverse equivalent ionic current can also be realized. Directional transport of photogenerated electrons and holes results in a transmembrane potential, which is the basis of the light-driven ion transport phenomenon. As a proof of concept, we also show that this system can be used for enhanced osmotic energy generation. The artificial light-driven ion transport system proposed here offers a further step forward on the roadmap for development of ionic photoelectric conversion and integration into other applications, for example water desalination. 相似文献
92.
Zhizhi Sheng Mengchuang Zhang Jing Liu Paolo Malgaretti Jianyu Li Shuli Wang Wei Lv Rongrong Zhang Yi Fan Yunmao Zhang Xinyu Chen Xu Hou 《国家科学评论(英文版)》2021,8(5)
Collective dynamics of confined colloids are crucial in diverse scenarios such as self-assembly and phase behavior in materials science, microrobot swarms for drug delivery and microfluidic control. Yet, fine-tuning the dynamics of colloids in microscale confined spaces is still a formidable task due to the complexity of the dynamics of colloidal suspension and to the lack of methodology to probe colloids in confinement. Here, we show that the collective dynamics of confined magnetic colloids can be finely tuned by external magnetic fields. In particular, the mechanical properties of the confined colloidal suspension can be probed in real time and this strategy can be also used to tune microscale fluid transport. Our experimental and theoretical investigations reveal that the collective configuration characterized by the colloidal entropy is controlled by the colloidal concentration, confining ratio and external field strength and direction. Indeed, our results show that mechanical properties of the colloidal suspension as well as the transport of the solvent in microfluidic devices can be controlled upon tuning the entropy of the colloidal suspension. Our approach opens new avenues for the design and application of drug delivery, microfluidic logic, dynamic fluid control, chemical reaction and beyond. 相似文献
93.
Paolo Savoia 《Metascience》2016,25(2):255-258
94.
95.
Tommaso Agasisti Antonio Dal Bianco Paolo Landoni Alessandro Sala Mario Salerno 《Higher Education Quarterly》2011,65(3):267-289
This paper investigates the efficiency of university departments in science, technology and medicine in an Italian Region (Lombardy). The aim of the paper is twofold: (i) to analyse the changes in productivity in recent years (from 2004 and 2007); and (ii) to detect factors that are potentially affecting efficiency. The research benefited from a new and unique dataset (called QuESTIO) developed by the Lombardy Regional Government. Using facilities and academic staff as inputs and research grants and publications as outputs, the research activity of academic departments was modelled. The methodological approach for computing efficiency scores is (DEA) Data Envelopment Analysis; Malmquist indexes have been used to measure changes in productivity, while Kruskal‐Wallis tests were employed to study the potential determinants of efficiency. Two main results were obtained. First, the academic departments improved their efficiency but, at the same time, the efficiency frontier worsened. Second, external and measurable factors (such as scientific sector, proportion of tenured staff, location, etc.) have a limited impact in explaining efficiency differentials. The policy implications of both results are discussed. 相似文献
96.
Paolo Garraffa 《体育科研》2014,(4):12-18
研究意大利和国际体育法判例制裁的比例原则,首先需要了解意大利(以下简称国家)和国际体育规则。其次是根据意大利与国际体育法的判例如何与归责原则连接,以及解释(和执行)方式,尤其是关于足球与反兴奋剂规则。研究的主要目的是为了验证这一原则是否在规则中被编撰和认可(通过体育法庭得到解释和执行),评估这一原则是否应用于保护体育运动的完整性(确保它的正常运作),并应当平衡要遵守体育规则和保护运动员利益二者之间的关系。 相似文献
97.
Biscarini A Benvenuti P Botti F Mastrandrea F Zanuso S 《Journal of sports sciences》2011,29(5):457-469
An analytical biomechanical model was developed to establish the relevant properties of the Smith squat exercise, and the main differences from the free barbell squat. The Smith squat may be largely patterned to modulate the distributions of muscle activities and joint loadings. For a given value of the included knee angle (θ(knee)), bending the trunk forward, moving the feet forward in front of the knees, and displacing the weight distribution towards the forefoot emphasizes hip and lumbosacral torques, while also reducing knee torque and compressive tibiofemoral and patellofemoral forces (and vice versa). The tibiofemoral shear force φ(t) displays more complex trends that strongly depend on θ(knee). Notably, for 180° ≥ θ(knee) ≥ 130°, φ(t) and cruciate ligament strain forces can be suppressed by selecting proper pairs of ankle and hip angles. Loading of the posterior cruciate ligament increases (decreases) in the range 180° ≥ θ(knee) ≥ 150° (θ(knee) ≤ 130°) with knee extension, bending the trunk forward, and moving the feet forward in front of the knees. In the range 150° > θ(knee) > 130°, the behaviour changes depending on the foot weight distribution. The conditions for the development of anterior cruciate ligament strain forces are explained. This work enables careful use of the Smith squat in strengthening and rehabilitation programmes. 相似文献
98.
Danilo Bersani Pier Paolo Lottici Antonella Casoli Diego Cauzzi 《Journal of Cultural Heritage》2008,9(1):97-102
During the restoration plan of the famous painting “Madonna col Bambino e S. Giovannino” by Sandro Botticelli, located in the Museo Civico of Piacenza (Italy), a study on painting materials was carried out. The pigments, the binders and the materials used for the application of ground and priming layers were studied using micro-Raman spectroscopy, gas chromatography coupled with mass spectrometry (GC/MS), optical and electronic microscopies. Gypsum and anhydrite were found in the ground layer, while carbon black and lead white were used in the priming layers. The precious pigments of the artist's palette and the binders used (egg and animal glue) were determined. 相似文献
99.
100.
Franco Sandrolini Elisa Franzoni Enrico Sassoni Pier Paolo Diotallevi 《Journal of Cultural Heritage》2011,12(4):441
The problem of environmental monitoring aimed at identifying and evaluating the weathering mechanisms affecting historical stoneworks is here discussed and a methodology based on the use of already available, long record, urban-scale environmental data is proposed. An example of its application to the Cathedral of Modena (Italy, XII-XIV century, included in the UNESCO's World Heritage List) is then presented. In this case, the methodology allowed the identification of the main degradation causes, which found significant confirmation by material diagnostics on the available samples and finite element structural modelling. Thanks to the decay causes identification allowed by the proposed methodology, more effective restoration procedures can be outlined. 相似文献