5,279 research outputs found

    Inverter-Based Low-Voltage CCII- Design and Its Filter Application

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    This paper presents a negative type second-generation current conveyor (CCII-). It is based on an inverter-based low-voltage error amplifier, and a negative current mirror. The CCII- could be operated in a very low supply voltage such as ±0.5V. The proposed CCII- has wide input voltage range (±0.24V), wide output voltage (±0.24V) and wide output current range (±24mA). The proposed CCII- has no on-chip capacitors, so it can be designed with standard CMOS digital processes. Moreover, the architecture of the proposed circuit without cascoded MOSFET transistors is easily designed and suitable for low-voltage operation. The proposed CCII- has been fabricated in TSMC 0.18Όm CMOS processes and it occupies 1189.91 x 1178.43Όm2 (include PADs). It can also be validated by low voltage CCII filters

    Anomalous physical properties of underdoped weak-ferromagnetic superconductor RuSr2_2EuCu2_{2}O8_{8}

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    Similar to the optimal-doped, weak-ferromagnetic (WFM induced by canted antiferromagnetism, TCurie_{Curie} = 131 K) and superconducting (Tc_{c} = 56 K) RuSr2_{2}GdCu2_{2}O8_{8}, the underdoped RuSr2_{2}EuCu2_{2}O8_{8} (TCurie_{Curie} = 133 K, Tc_{c} = 36 K) also exhibited a spontaneous vortex state (SVS) between 16 K and 36 K. The low field (±\pm20 G) superconducting hysteresis loop indicates a weak and narrow Meissner state region of average lower critical field Bc1ave_{c1}^{ave}(T) = Bc1ave_{c1}^{ave}(0)[1 - (T/TSVS_{SVS})2^{2}], with Bc1ave_{c1}^{ave}(0) = 7 G and TSVS_{SVS} = 16 K. The vortex melting transition (Tmelting_{melting} = 21 K) below Tc_{c} obtained from the broad resistivity drop and the onset of diamagnetic signal indicates a vortex liquid region due to the coexistence and interplay between superconductivity and WFM order. No visible jump in specific heat was observed near Tc_{c} for Eu- and Gd-compound. This is not surprising, since the electronic specific heat is easily overshadowed by the large phonon and weak-ferromagnetic contributions. Furthermore, a broad resistivity transition due to low vortex melting temperature would also lead to a correspondingly reduced height of any specific heat jump. Finally, with the baseline from the nonmagnetic Eu-compound, specific heat data analysis confirms the magnetic entropy associated with antiferromagnetic ordering of Gd3+^{3+} (J = S = 7/2) at 2.5 K to be close to NAk\it{N_{A}k} ln8 as expected.Comment: 7 figure

    Thermal analysis comparison between two random glass fibre reinforced thermoplastic matrix composites bonded by adhesives using microwaves: preliminary results

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    [Abstract]: This paper compares the thermal analysis of two types of random glass fibre reinforced thermoplastic matrix composites joined by adhesives using microwave energy. Fixed frequency, 2.45 GHz, microwave facility is used to join thirty three percent by weight random glass fibre reinforced polystyrene composite [PS/GF (33%)] and thirty three percent by weight random glass fibre reinforced low density polyethylene composite [LDPE/GF (33%)]. The facility used is shown in Figure 1. With a given power level, the composites were exposed to various exposure times to microwave irradiation. The primer or coupling agent used was 5-minute two-part adhesive. The heat distribution of the samples of the two types of composites was analysed and compared. The relationship between the heat distribution and the lap shear strength of the samples was also compared and discussed

    Anisotropic superconducting properties of aligned Sm0.95_{0.95}La0.05_{0.05}FeAsO0.85_{0.85}F0.15_{0.15} microcrystalline powder

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    The Sm0.95_{0.95}La0.05_{0.05}FeAsO0.85_{0.85}F0.15_{0.15} compound is a quasi-2D layered superconductor with a superconducting transition temperature Tc_c = 52 K. Due to the Fe spin-orbital related anisotropic exchange coupling (antiferromagnetic or ferromagnetic fluctuation), the tetragonal microcrystalline powder can be aligned at room temperature using the field-rotation method where the tetragonal ab\it{ab}-plane is parallel to the aligned magnetic field Ba_{a} and c\it{c}-axis along the rotation axis. Anisotropic superconducting properties with anisotropic diamagnetic ratio χc/χab∌\chi_{c}/\chi_{ab}\sim 2.4 + 0.6 was observed from low field susceptibility χ\chi(T) and magnetization M(Ba_{a}). The anisotropic low-field phase diagram with the variation of lower critical field gives a zero-temperature penetration depth λc\lambda_{c}(0) = 280 nm and λab\lambda_{ab}(0) = 120 nm. The magnetic fluctuation used for powder alignment at 300 K may be related with the pairing mechanism of superconductivity at lower temperature.Comment: 4 pages, 6 figure

    Pulsed THz radiation due to phonon-polariton effect in [110] ZnTe crystal

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    Pulsed terahertz (THz) radiation, generated through optical rectification (OR) by exciting [110] ZnTe crystal with ultrafast optical pulses, typically consists of only a few cycles of electromagnetic field oscillations with a duration about a couple of picoseconds. However, it is possible, under appropriate conditions, to generate a long damped oscillation tail (LDOT) following the main cycles. The LDOT can last tens of picoseconds and its Fourier transform shows a higher and narrower frequency peak than that of the main pulse. We have demonstrated that the generation of the LDOT depends on both the duration of the optical pulse and its central wavelength. Furthermore, we have also performed theoretical calculations based upon the OR effect coupled with the phonon-polariton mode of ZnTe and obtained theoretical THz waveforms in good agreement with our experimental observation.Comment: 9 pages, 5 figure

    Capturing human category representations by sampling in deep feature spaces

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    Understanding how people represent categories is a core problem in cognitive science. Decades of research have yielded a variety of formal theories of categories, but validating them with naturalistic stimuli is difficult. The challenge is that human category representations cannot be directly observed and running informative experiments with naturalistic stimuli such as images requires a workable representation of these stimuli. Deep neural networks have recently been successful in solving a range of computer vision tasks and provide a way to compactly represent image features. Here, we introduce a method to estimate the structure of human categories that combines ideas from cognitive science and machine learning, blending human-based algorithms with state-of-the-art deep image generators. We provide qualitative and quantitative results as a proof-of-concept for the method's feasibility. Samples drawn from human distributions rival those from state-of-the-art generative models in quality and outperform alternative methods for estimating the structure of human categories.Comment: 6 pages, 5 figures, 1 table. Accepted as a paper to the 40th Annual Meeting of the Cognitive Science Society (CogSci 2018

    State and Industrial Policy: Comparative Political Economic Analysis of Automotive Industrial Policies in Malaysia and Thailand

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    Numerous differences exist between the neoclassical and national development schools of economics on how an economy should develop. For example, should the state interfere in the market using state resources, and cultivate certain industries to achieve specific developmental goals? Although the automotive industries in both Thailand and Malaysia developed in the 1970s with considerable government involvement, they have evolved along very different lines. Can these differences be traced to different interactions between the state and industry in these two countries? This paper examines this issue and finds that although industries in developing countries need government assistance, the specific political and economic contexts of each country affect the policies adopted and their effectiveness. The choice between “autonomous development” (Malaysia) and “dependent development” (Thailand) is the first issue. The second issue is that politics in Malaysia has deterred the automotive industry from adopting a “market following” position. This paper finds that the choice of strategy and political interference are the two main reasons the automotive industry in Malaysia is less competitive than that in Thailand

    Complete classification of steerability under local filters and its relation with measurement incompatibility

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    Quantum steering is a central resource for one-sided device-independent quantum information. It is manipulated via one-way local operations and classical communication, such as local filtering on the trusted party. Here, we provide a necessary and sufficient condition for a steering assemblage to be transformable into another via local filtering. We characterize the equivalence classes with respect to filters in terms of the steering equivalent observables (SEO), first proposed to connect the problem of steerability and measurement incompatibility. We provide an efficient method to compute the extractable steerability that is maximal via local filters and show that it coincides with the incompatibility of the SEO. Moreover, we show that there always exists a bipartite state that provides an assemblage with steerability equal to the incompatibility of the measurements on the untrusted party. Finally, we investigate the optimal success probability and rates for transformation protocols (distillation and dilution) in the single-shot scenario together with examples
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