2,084 research outputs found
Detection of weak stochastic forces in a parametrically stabilized micro-optomechanical system
No full textMeasuring a weak force is an important task for micromechanical systems, both when using devices as sensitive detectors and, particularly, in experiments of quantum mechanics. The optimal strategy for resolving a weak stochastic signal force on a huge background (typically given by thermal noise) is a crucial and debated topic, and the stability of the mechanical resonance is a further, related critical issue. We introduce and analyze the parametric control of the optical spring, which allows us to stabilize the resonance and provides a phase reference for the oscillator motion, yet conserving a free evolution in one quadrature of the phase space. We also study quantitatively the characteristics of our micro-optomechanical system as detector of stochastic force for short measurement times (for quick, high-resolution monitoring) as well as for the longer-term observations that optimize the sensitivity. We compare a simple strategy based on the evaluation of the variance of the displacement which is a widely used technique) with an optimal Wiener-Kolmogorov data analysis. We show that, due to the parametric stabilization of the effective susceptibility, we can more efficiently implement Wiener filtering, and we investigate how this strategy improves the performance of our system. We finally demonstrate the possibility to resolve stochastic force variations well below 1% of the thermal noise.MicroelectronicsElectrical Engineering, Mathematics and Computer Scienc
Measurements of newly defined intensimetric quantities and their physical interpretation
No full textThis paper deals with the measurement and physical interpretation of the quantities a and r introduced in a previous paper [D. Stanzial, N. Prodi, and G. Schiffrer. 'Reactive intensity for general fields and energy polarization,' J. Acoust. Sec. Am. 99, 1868-1876 (1996)]. The quantity a, which has the same time dependence as the squared acoustic pressure arid the same direction as the time averaged sound intensity , will be called here 'radiating' intensity, while r which has zero average, will be called 'oscillating' intensity. A coherent picture of the energy transfer process in steady sound fields based on the decomposition j = a+r of the instantaneous sound intensity will be sketched and discussed. Furthermore, a direct experimental comparison between a and r and the real and imaginary parts of the complex intensity is presented for some field conditions
Economic relations between Italy and China
No full textChina is the world’s largest fast-growing middle-income country, while Italy remains the eighth economy globally, but with a gross domestic product (GDP) that has now been contracting for three of the past five years (2008, 2009, and 2012), declining over 6 percent since the start of the global financial crisis. Yet, China and Italy display some striking similarities in their economic structures. Both countries rely heavily on manufacturing, and there is an overlap between the industrial sectors in which both specialize. 1 Manufacturing industries in Italy cluster in certain locations and consist mostly of small and medium enterprises (SMEs), much the way production chains are organized in some parts of China, especially in key provinces such as Zhejiang and Guangdong. As this chapter will argue, such similarities have profound consequences on bilateral economic relations
China 2025 e politiche commerciali: asimmetrie di potere e difficoltà nella cooperazione sino-europea
No full textAnche la Cina, come tutti i paesi industrializzati, si trova a dover affrontare le sfide poste dalla cosiddetta “Industry 4.0” che include lo sviluppo e integrazione di nuovi materiali e di tecnologie come la robotica, l’Internet delle cose, l’added manufacturing, la cybersecurity. Anzi, per la Cina si tratta di una sfida forse ancora più complessa
China 2025 e politiche commerciali: asimmetrie di potere e difficoltà nella cooperazione sino-europea
No full textAnche la Cina, come tutti i paesi industrializzati, si trova a dover affrontare le sfide poste dalla cosiddetta “Industry 4.0” che include lo sviluppo e integrazione di nuovi materiali e di tecnologie come la robotica, l’Internet delle cose, l’added manufacturing, la cybersecurity. Anzi, per la Cina si tratta di una sfida forse ancora più complessa
DNA Quantification to Assess Zymoseptoria tritici on a Susceptible Cultivar of Durum Wheat to Establish the Best Timing for Fungicide Application in an Italian Environment
No full textZymoseptoria tritici, a globally distributed pathogen, is responsible of Septoria tritici blotch (STB), one of the most damaging wheat diseases. In Italy the incidence of STB has increased during the past few years. The presence of Z. tritici on flag leaves of susceptible durum wheat plants, cultivar San Carlo, after a single artificial inoculation with two inoculum concentrations at different vegetative stages has been evaluated in the plain of Bologna (North of Italy), in a two year field study (2012–2013). The pathogen presence was also assessed in natural infection conditions after a fungicide application in the second year (2013). The results obtained, by visual examination (Incidence, Disease Severity) and DNA quantification by Real time PCR, demonstrated that BBCH 39 (flag leaf stage) is the most susceptible vegetative stage, independently of inoculum concentration and climatic conditions. A good correlation between Disease Severity and DNA quantity was observed in either sampling methods, entire flag leaves and flag leaf discs. Thereafter the most suitable period to obtain the best crop protection with only one fungicide treatment is the flag leaf stage
Entry strategies into China: The choice between Joint Ventures and Wholly Foreign-Owned Enterprises: An application to the Italian manufacturing sector
No full textWe investigate the entry choice between Joint Ventures and Wholly Foreign-Owned Enterprises in the Chinese market. The analysis is based on Italian firms, thus allowing to evaluate the behaviour of also small-medium sized companies — usually less focused on by the literature on entry modes. The data, mainly from a questionnaire, supply detailed enterprise-level information and make possible to properly measure and evaluate the impact on entry modes of several variables such as innovation, internationalization, and, new in the empirical literature on this issue, corporate capital structure
Innovative renewal of ceramic-tile manufacturing in Sassuolo: A local manufacturing system between tradition and restructuring
No full textInnovative renewal of manufacturing in Sassuolo (Italy) is presented as a response to some of the most recent transformations in the global ceramic-tile industry. This response consists in a shift to a higher-value product segment (gres) and it is underpinned by the evolution of the local system as a whole. Four main pillars are identified: the tradition of the Italian industrial districts whose Sassuolo is a renowned example, the reconfiguration of structures and ties, revisited cross-sectoral complementarities, and the interaction with public policy. These dynamics are tightly intertwined and so, the discussion most case-specific. Nonetheless, systematic private-private and public-private interactions and the alignment of public policy with the trajectories of change can be derived as the main implications for policy making aimed to support innovative renewal in mature economies
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