207 research outputs found
Nanoscopic Tunneling Contacts on Mesoscopic Multiprobe Conductors
We derive Bardeen-like expressions for the transmission probabilities between
two multi-probe mesoscopic conductors coupled by a weak tunneling contact. We
emphasize especially the dual role of a weak coupling contact as a current
source and sink and analyze the magnetic field symmetry. In the limit of a
point-like tunneling contact the transmission probability becomes a product of
local, partial density of states of the two mesoscopic conductors. We present
expressions for the partial density of states in terms of functional
derivatives of the scattering matrix with respect to the local potential and in
terms of wave functions. We discuss voltage measurements and resistance
measurements in the transport state of conductors. We illustrate the theory for
the simple case of a scatterer in an otherwise perfect wire. In particular, we
investigate the development of the Hall-resistance as measured with weak
coupling probes.Comment: 10 pages, 5 figures, revte
'A habitual disposition to the good': on reason, virtue and realism
Amidst the crisis of instrumental reason, a number of contemporary political philosophers including JĂŒrgen Habermas have sought to rescue the project of a reasonable humanism from the twin threats of religious fundamentalism and secular naturalism. In his recent work, Habermas defends a post-metaphysical politics that aims to protect rationality against encroachment while also accommodating religious faith within the public sphere. This paper contends that Habermasâ post-metaphysical project fails to provide a robust alternative either to the double challenge of secular naturalism and religious fundamentalism or to the ruthless instrumentalism that underpins capitalism. By contrast with Habermas and also with the ânew realismâ of contemporary political philosophers such as Raymond Geuss or Bernard Williams, realism in the tradition of Plato and Aristotle can defend reason against instrumental rationality and blind belief by integrating it with habit, feeling and even faith. Such metaphysicalâpolitical realism can help develop a politics of virtue that goes beyond communitarian thinking by emphasising plural modes of association (not merely âcommunityâ), substantive ties of sympathy and the importance of pursuing goodness and mutual flourishing
Syngas generation from n-butane with an integrated MEMS assembly for gas processing in micro-solid oxide fuel cell systems
An integrated system of a microreformer and a carrier allowing for syngas generation from liquefied petroleum gas (LPG) for micro-SOFC application is discussed. The microreformer with an overall size of 12.7 mm Ă 12.7 mm Ă 1.9 mm is fabricated with micro-electro-mechanical system (MEMS) technologies. As a catalyst, a special foam-like material made from ceria-zirconia nanoparticles doped with rhodium is used to fill the reformer cavity of 58.5 mm3. The microreformer is fixed onto a microfabricated structure with built-in fluidic channels and integrated heaters, the so-called functional carrier. It allows for thermal decoupling of the cold inlet gas and the hot fuel processing zone. Two methods for heating the microreformer are compared in this study: a) heating in an external furnace and b) heating with the two built-in heaters on the functional carrier. With both methods, high butane conversion rates of 74%â85% are obtained at around 550 °C. In addition, high hydrogen and carbon monoxide yields and selectivities are achieved. The results confirm those from classical lab reformers built without MEMS technology (N. Hotz et al., Chem. Eng. Sci., 2008, 63, 5193; N. Hotz et al., Appl. Catal., B, 2007, 73, 336). The material combinations and processing techniques enable syngas production with the present MEMS based microreformer with high performance for temperatures up to 700°C. The functional carrier is the basis for a new platform, which can integrate the micro-SOFC membranes and the gas processing unit as subsystem of an entire micro-SOFC system
Special Libraries, April 1933
Volume 24, Issue 3https://scholarworks.sjsu.edu/sla_sl_1933/1002/thumbnail.jp
Political Economy of Civil Society
This chapter explores the role of civil society in relation to the economy and the polity by focusing on three distinct yet related dimensions: (1) the conceptual history of civil society in relation to political economy; (2) the theory underpinning a political economy of civil society; (3) the implications of a political economy of civil society for policy-making. The main argument is that there is a fundamental difference between ancient and medieval conceptions, which emphasise natural sociability, and modern accounts that accentuate a violent âstate of natureâ. As a result, civil society either reflects the fundamental embeddedness of economic and political processes in social relations or is an artificial construct. The chapter develops a typology of four modern models, provides a theory of the political economy of civil society and outlines a series of policy ideas
Active layers of high-performance lead zirconate titanate at temperatures compatible with silicon nano- and microelecronic devices
Applications of ferroelectric materials in modern microelectronics will be greatly encouraged if the
thermal incompatibility between inorganic ferroelectrics and semiconductor devices is overcome.
Here, solution-processable layers of the most commercial ferroelectric compound â morphotrophic
phase boundary lead zirconate titanate, namely Pb(Zr0.52Ti0.48)O3 (PZT) â are grown on silicon
substrates at temperatures well below the standard CMOS process of semiconductor technology.
The method, potentially transferable to a broader range of Zr:Ti ratios, is based on the addition of
crystalline nanoseeds to photosensitive solutions of PZT resulting in perovskite crystallization from
only 350 °C after the enhanced decomposition of metal precursors in the films by UV irradiation. A
remanent polarization of 10.0 ÎŒC cmâ2 is obtained for these films that is in the order of the switching
charge densities demanded for FeRAM devices. Also, a dielectric constant of ~90 is measured at
zero voltage which exceeds that of current single-oxide candidates for capacitance applications. The
multifunctionality of the films is additionally demonstrated by their pyroelectric and piezoelectric
performance. The potential integration of PZT layers at such low fabrication temperatures may redefine
the concept design of classical microelectronic devices, besides allowing inorganic ferroelectrics to
enter the scene of the emerging large-area, flexible electronics
Gardens of happiness: Sir William Temple, temperance and China
This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordSir William Temple, an English statesman and humanist, wrote âUpon the
Gardens of Epicurusâ in 1685, taking a neo-epicurean approach to happiness
and temperance. In accord with Pierre Gassendiâs epicureanism, âhappinessâ is
characterised as freedom from disturbance and pain in mind and body, whereas
âtemperanceâ means following nature (Providence and oneâs physiopsychological constitution). For Temple, cultivating fruit trees in his garden was
analogous to the threefold cultivation of temperance as a virtue in the humoral
body (as food), the mind (as freedom from the passions), and the bodyeconomic (as circulating goods) in order to attain happiness. A regimen that was
supposed to cure the malaise of Restoration amidst a crisis of unbridled
passions, this threefold cultivation of temperance underlines Templeâs reception
of China and Confucianism wherein happiness and temperance are highlighted.
Thus Templeâs âgardens of happinessâ represent not only a reinterpretation of
classical ideas, but also his dialogue with China.European CommissionLeverhulme Trus
Aluminum nitride thin films for high frequency applications
A piezoelectric thin film sandwiched between two conductors is the basic structure for high frequency bulk acoustic wave devices. For that purpose, AlN thin films deposited by DC reactive sputtering on various electrode materials were investigated, Highly c-axis oriented thin films as thick as 2.5 mu m were grown on various substrates and analyzed. Intrinsic stress values ranging from strong compression to high tension were observed and piezoelectric d(33,f) coefficients up to 3.9 pm/V were measured. The first fabricated acoustic resonators showed a pronounced resonance peak centered at 2 GHz with a very high Q factor
Studies on Double Refraction of Flow I. An Apparatus for the Study of Double Refraction of Flow at High Velocity Gradients
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