Concepts for a class of novel piezoelectric self-locking long-stroke actuators

The friction-type motor is the most common type in the field of piezoelectric motors. One limitation of friction-type motors is their inability to achieve high output push force or torque. Based on the theory of self-lock, a novel mechanism for the linear piezoelectric motor is proposed. On the basis of the proposed mechanism, three prototype models have been developed. The new motors transfer the force and displacement generated by a piezoelectric actuator to the output directly, whereas the friction-type motor transfers via the induced friction between the stator and the rotor. The achieved positioning precision is within 10 nm, while the push force is up to 1,176 N. The new motors can be applied in cases where both high positioning precision and heavy load are essential.     

Influence of sn‐1,3‐lipase‐catalysed interesterification on the oxidative stability of soybean oil‐based structured lipids

The oxidative stability of structured lipids (SLs) synthesised by specific sn‐1,3‐lipase catalysed interesterification of soybean oil (SBO) with caprylic acid (CA) in a stirred batch reactor was studied. SLs contained considerable amounts of tocopherol (TOH) isomers, although they lost almost 25% of endogenous TOHs during production. The effects of the addition of different TOH homologues (α, β, γ, δ), ascorbyl palmitate (AP, 200 ppm), lecithin (Le, 1000 ppm), butylated hydroxytoluene (BHT, 100 ppm) and butylated hydroxyanisole (BHA, 100 ppm) on the oxidative stability of SLs were investigated. Induction time (IT) of SBO, determined by the Rancimat method, decreased from 8.4 to 5.8 h at 110 °C after the modification. On the other hand, purified SLs and purified SBO had the same IT due to the tocopherol reduction during silica purification. No significant difference was observed between IT of SLs and SLs plus different α‐tocopherol concentrations (50, 100, 150, 200, 300, 500 and 1000 ppm) (P > 0.05). However, the addition of Le and/or AP significantly improved oxidative stability of purified SLs and SBO. The ternary blend containing δ‐TOH, AP and Le had higher IT than ternary blends of α‐TOH, β‐TOH or γ‐TOH. Furthermore, ternary blend containing BHA, AP and Le had higher IT than ternary blends of BHT, AP and Le. In addition, there was an increase in peroxide value (PV), conjugated diene (CD) content and p‐anisidine value (AV) during oxidation of oils at 60 °C. Antioxidant mixtures of α‐TOH (50 ppm) and δ‐TOH (500 ppm) with AP and Le decreased PV, CD and AV effectively. Copyright © 2006 Society of Chemical Industry     

Output Peak Control of Nonhomogeneous Markov Jump System with Unit-Energy Disturbance

This paper considers output peak controller design for discrete nonhomogeneous Markov jump systems under unit-energy disturbance. The mode-dependent output peak feedback controller is designed to ensure that the resulting closed-loop system is stochastically stable and the peak of the output is within a specified range. Furthermore, the optimal energy-to-peak gain indices of the mode-dependent and the mode-independent state feedback controllers are evaluated and compared. A numerical example is presented to illustrate the applicability of the results obtained.     

The organization and control of an evolving interdependent population

Starting with Darwin, biologists have asked how populations evolve from a low fitness state that is evolutionarily stable to a high fitness state that is not. Specifically of interest is the emergence of cooperation and multicellularity where the fitness of individuals often appears in conflict with that of the population. Theories of social evolution and evolutionary game theory have produced a number of fruitful results employing two-state two-body frameworks. In this study, we depart from this tradition and instead consider a multi-player, multi-state evolutionary game, in which the fitness of an agent is determined by its relationship to an arbitrary number of other agents. We show that populations organize themselves in one of four distinct phases of interdependence depending on one parameter, selection strength. Some of these phases involve the formation of specialized large-scale structures. We then describe how the evolution of independence can be manipulated through various external perturbations.     

One size fits all? Policy instruments should fit the segments of target groups

In order to meet the Kyoto CO₂ reduction targets, technical innovations in the field of energy-efficiency must diffuse more rapidly into a larger market. However, markets develop gradually, especially if innovations are involved. Diffusion starts with the early market (innovators and early adopters), followed by the mainstream market (the early and late majority), and ends with the laggards. The actors in these markets differ in their willingness to adopt innovations; the early market actors have a visionary attitude, and the mainstream market actors are more pragmatic. In order to choose policy instruments that will most effectively influence these two markets within the target group of housing association, we addressed the following two questions. (1) What are the differences between the early and mainstream market actors from a behavioural-change point of view? (2) In what way do existing policy instruments differ in influencing the behaviour of these actors? We analyzed early market and mainstream decision-making behaviours, and how the active ingredients in policy instruments specifically target the characteristics of the two markets. Mainstream instruments should intervene as early as possible in the decision-making process and emphasize communication about advantages such as comfort and quality in addition to money and energy savings. Furthermore, they should present energy conservation as a solution to an actual problem. Instead of bureaucratic subsidy systems for the mainstream, the motto should be “cash on the barrel-head”. Early market actors are highly internally motivated, implying that early market interventions have to be challenging and facilitating.     

Polarization dynamics and non-equilibrium switching processes in ferroelectrics

Time- and temperature-dependent effects are critical for the operation of non-volatile memories based on ferroelectrics. In this paper, we assume a domain nucleation process of the polarization reversal and we discuss the polarization dynamics in the framework of a non-equilibrium statistical model. This approach yields analytical expressions which can be used to explain a wide range of time- and temperature-dependent effects in ferroelectrics. Domain wall velocity derived in this work is consistent with a domain wall creep behavior in ferroelectrics. In the limiting case of para-electric equilibrium, the model yields the well-known Curie law. We also present experimental P-E loops data obtained for soft ferroelectrics at various temperatures. The experimental coercive fields at various temperatures are well predicted by the coercive field formula derived in our theory.     

Performance enhancement in organic photovoltaic devices using plasma-polymerized fluorocarbon-modified Ag nanoparticles

In this work, Ag nanoparticles were modified by an ultra-thin plasma-polymerized fluorocarbon film (CF_X) to form a composite CF_X-modified Ag nanoparticles/indium tin oxide (ITO) anode for application in organic photovoltaic (OPV) devices. A CF_X-modified Ag nanoparticles/ITO anode exhibited a superior surface work function of 5.4 eV suited for application in OPV devices. The performance of zinc phthalocyanine:fullerene-based OPV devices showed a significant improvement when the structural identical cells are made with the CF_X-modified Ag nanoparticles/ITO. This work yielded a promising power conversion efficiency of 3.5 ± 0.1%, notably higher than that with a bare ITO anode (2.7 ± 0.1%).     

Resonance condition of a microfiber knot resonator immersed in liquids

Effects of immersing a microfiber knot resonator (MKR) in liquid solutions that have refractive indices close to that of silica are experimentally demonstrated and theoretically analyzed. Significant improvement in resonance extinction ratio within 2 to 10 dB was observed. To achieve a better understanding, a qualitative analysis of the coupling ratio and round-trip attenuation of the MKR is performed by using a curve-fitting method. It was observed that the coupling coefficient at the knot region increased when immersed in liquids. However, depending on the initial state of the coupling and the quantity of the increment in the coupling coefficient when immersed in a liquid, it is possible that the MKR may experience a deficit in the coupling parameter due to the sinusoidal relationship with the coupling coefficient.