General analysis on the use of tesla's resonators in domino forms for wireless power transfer

In this paper, we present a brief overview of historical developments of wireless power and an analysis on the use of Tesla's resonators in domino forms for wireless power transfer. Relay resonators are spaced between the transmitter and receiver coils with the objectives of maximizing energy efficiency and increasing the overall transmission distance between the power source and the load. Analytical expressions for the optimal load and maximum efficiency at resonance frequency are derived. These equations are verified with practical measurements obtained from both coaxial and noncoaxial domino resonator systems. To avoid the use of high operating frequency for wireless power transfer in previous related research, the technique presented here can be used at submegahertz operation so as to minimize the power loss in both the power supply and the output stage. We demonstrated both theoretically and practically that unequal spacing for the coaxial straight domino systems has better efficiency performance than the equal-spacing method. Also, the flexibility of using resonators in various domino forms is demonstrated. © 2012 IEEE.published_or_final_versio

《學習2.0》：一個支援新高中通識教育及專題研究的學習及評估平臺

Liberal Studies as a mandatory subject in the New Secondary School curriculum will be implemented starting from September 2009. This subject adopts an inquiry-based approach and the content is structured around a range of important contemporary issues. Teachers face new challenges in teaching and assessing this subject: how to guide students to read critically, find useful information from the internet, formulate inquiry questions and to undertake evidence-based inquiry; how to support student collaboration and at the same time be able to assess the efforts and achievements of individual students; and how to provide adequate feedback to students at various stages of inquiry such that assessment can be both formative and summative. In addition, facilitating students to work autonomously online generally brings heavy workload on teachers. This paper introduces the Learning 2.0 project which comprises the development of an open-source online learning and assessment platform using Web 2.0 technology to provide support for the learning and teaching in the NSS Liberal Studies Curriculum.published_or_final_versio

Effects of metallic spacer in layered superconducting Sr2(Mgy_yTi1−y_{1-y})O3FeAs

The highly two-dimensional superconducting system Sr2(Mg$_y$Ti$_{1-y}$)O3FeAs, recently synthesized in the range of 0.2 < y < 0.5, shows an Mg concentration-dependent $T_c$. Reducing the Mg concentration from y=0.5 leads to a sudden increase in $T_c$, with a maximum $T_c$ ~40 K at y=0.2. Using first principles calculations, the unsynthesized stoichiometric y=0 and the substoichiometric y=0.5 compounds have been investigated. For the 50% Mg-doped phase (y=0.5), Sr2(Mg$_y$Ti$_{1-y}$)O3 layers are completely insulating spacers between FeAs layers, leading to the fermiology such as that found for other Fe pnictides. At y=0, representing a phase with metallic Sr2TiO3 layers, the $\Gamma$-centered Fe-derived Fermi surfaces (FSs) considerably shrink or disappear. Instead, three $\Gamma$-centered Ti FSs appear, and in particular two of them have similar size, like in MgB2. Interestingly, FSs have very low Fermi velocity in large fractions: the lowest being 0.6$\times10^6$ cm/s. Furthermore, our fixed spin moment calculations suggest the possibility of magnetic ordering, with magnetic Ti and nearly nonmagnetic Fe ions. These results indicate a crucial role of Sr2(Mg$_y$Ti$_{1-y}$)O3 layers in this superconductivity.Comment: 7 pages; Proceedings of ICSM-201

Heisenberg-picture approach to the exact quantum motion of a time-dependent forced harmonic oscillator

In the Heisenberg picture, the generalized invariant and exact quantum motions are found for a time-dependent forced harmonic oscillator. We find the eigenstate and the coherent state of the invariant and show that the dispersions of these quantum states do not depend on the external force. Our formalism is applied to several interesting cases.Comment: 15 pages, two eps files, to appear in Phys. Rev. A 53 (6) (1996

The nature and role of trap states in a dendrimer-based organic field-effect transistor explosive sensor

We report the fabrication and charge transport characterization of carbazole dendrimer-based organic field-effect transistors (OFETs) for the sensing of explosive vapors. After exposure to para-nitrotoluene (pNT) vapor, the OFET channel carrier mobility decreases due to trapping induced by the absorbed pNT. The influence of trap states on transport in devices before and after exposure to pNT vapor has been determined using temperature-dependent measurements of the field-effect mobility. These data clearly show that the absorption of pNT vapor into the dendrimer active layer results in the formation of additional trap states. Such states inhibit charge transport by decreasing the density of conducting states. (C) 2013 AIP Publishing LLC

Study protocol for a randomised controlled trial of invasive versus conservative management of primary spontaneous pneumothorax

INTRODUCTION: Current management of primary spontaneous pneumothorax (PSP) is variable, with little evidence from randomised controlled trials to guide treatment. Guidelines emphasise intervention in many patients, which involves chest drain insertion, hospital admission and occasionally surgery. However, there is evidence that conservative management may be effective and safe, and it may also reduce the risk of recurrence. Significant questions remain regarding the optimal initial approach to the management of PSP

Discovery of a ROCK inhibitor, FPND, which prevents cerebral hemorrhage through maintaining vascular integrity by interference with VE-cadherin

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Measurement of Cosmic-ray Muons and Muon-induced Neutrons in the Aberdeen Tunnel Underground Laboratory

We have measured the muon flux and production rate of muon-induced neutrons at a depth of 611 m water equivalent. Our apparatus comprises three layers of crossed plastic scintillator hodoscopes for tracking the incident cosmic-ray muons and 760 L of gadolinium-doped liquid scintillator for producing and detecting neutrons. The vertical muon intensity was measured to be $I_{\mu} = (5.7 \pm 0.6) \times 10^{-6}$ cm$^{-2}$s$^{-1}$sr$^{-1}$. The yield of muon-induced neutrons in the liquid scintillator was determined to be $Y_{n} = (1.19 \pm 0.08 (stat) \pm 0.21 (syst)) \times 10^{-4}$ neutrons/($\mu\cdot$g$\cdot$cm$^{-2}$). A fit to the recently measured neutron yields at different depths gave a mean muon energy dependence of $\left\langle E_{\mu} \right\rangle^{0.76 \pm 0.03}$ for liquid-scintillator targets.Comment: 14 pages, 17 figures, 3 table

Evaluation of deformity and hand function in cerebral palsy patients

<p>Abstract</p> <p>Background</p> <p>A cross-sectional study was performed to describe the upper limb deformity and function in cerebral palsy patients and to determine the correlation of deformity, spasticity, motor control, and sensation to hand function in the said population.</p> <p>Materials and methods</p> <p>Thirty patients satisfying our inclusion criteria underwent physical, sensory, and functional assessment using a standard protocol. Physical assessment included documentation of the degree of spasticity, deformity and muscle control. Sensation was tested using static two-point discrimination test and stereognosis test. Melbourne Assessment of the Unilateral Upper Limb Function Test (MAULF), Functional Hand Grip Test (FHGT), and Functional Independence Measure for children (WeeFIM) were used to evaluate hand function. Deformity, spasticity, motor control, and sensation were analyzed for correlation with hand function using Pearson Correlation analysis. A p-value of less than 0.05 was considered statistically significant.</p> <p>Results</p> <p>Functional deficits of the hand increased with increasing severity of deformity and spasticity. Tetraplegics were most affected by spasticity, deformity, poor motor control, sensory and functional deficits. Triplegics, followed by diplegics had more functional upper limbs in terms of the MAULF and FHGT scores. Unilaterally affected patients (triplegics and hemiplegics) scored better in performance of activities of daily living. The MAULF and FHGT had a stronger correlation to deformity, spasticity and motor control compared to the WeeFIM.</p> <p>Conclusion</p> <p>The degree of deformity, spasticity, sensory deficit, and motor control affected the hand function of a cerebral palsy patient significantly. The MAULF and FHGT more accurately represents hand function deficit in cerebral palsy patients.</p