8,701 research outputs found

    Implementing Inquiry-based Learning and Examining the Effects in Junior College Probability Lessons

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    This study examined how Year 12 students use their inquiry skills in solving conditional probability questions by means of Inquiry-Based Learning application. The participants consisted of 66 students of similar academic abilities in Mathematics, selected from three classes, along with their respective teachers. Observational rubric and lesson observation checklist were used as the data collection instruments. The results obtained were analyzed and then quantitatively reported. Findings from the observational rubric revealed that Year 12 students were able to understand most of the questions during the activity, but they only select and use one previously learned method to solve the questions during the activity. In addition, these students rarely seek and asked probing questions during the activity. They only used words, diagrams and numbers to interpret the solutions to the questions and make connections between them but with few mistakes detected.DOI: http://dx.doi.org/10.22342/jme.8.2.3964.157-16

    Origins of ferromagnetism in transition-metal doped Si

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    We present results of the magnetic, structural and chemical characterizations of Mn<sup>+</sup>-implanted Si displaying <i>n</i>-type semiconducting behavior and ferromagnetic ordering with Curie temperature,T<sub>C</sub> well above room temperature. The temperature-dependent magnetization measured by superconducting quantum device interference (SQUID) from 5 K to 800 K was characterized by three different critical temperatures (T*<sub>C</sub>~45 K, T<sub>C1</sub>~630-650 K and T<sub>C2</sub>~805-825 K). Their origins were investigated using dynamic secondary mass ion spectroscopy (SIMS) and transmission electron microscopy (TEM) techniques, including electron energy loss spectroscopy (EELS), Z-contrast STEM (scanning TEM) imaging and electron diffraction. We provided direct evidences of the presence of a small amount of Fe and Cr impurities which were unintentionally doped into the samples together with the Mn<sup>+</sup> ions, as well as the formation of Mn-rich precipitates embedded in a Mn-poor matrix. The observed T*<sub>C</sub> is attributed to the Mn<sub>4</sub>Si<sub>7</sub> precipitates identified by electron diffraction. Possible origins of and are also discussed. Our findings raise questions regarding the origin of the high ferromagnetism reported in many material systems without a careful chemical analysis

    Photon-induced production of the mirror quarks from the LHTLHT model at the LHCLHC

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    The photon-induced processes at the LHCLHC provide clean experimental conditions due to absence of the proton remnants, which might produce complementary and interesting results for tests of the standard model and for searching of new physics. In the context of the littlest HiggsHiggs model with T-parity, we consider the photon-induced production of the mirror quarks at the LHCLHC. The cross sections for various production channels are calculated and a simply phenomenology analysis is performed by assuming leptonic decays.Comment: 20 pages, 10 figure

    The Influence of Spatial Resolution due to Hot-Wire Sensors on Measurements in Wall-Bounded Turbulence.

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    Reassessment of compiled data reveal that recorded scatter in the hot-wire measured near-wall peak in viscous-scaled streamwise turbulence intensity is due in large part to the simultaneous competing effects of Reynolds number and viscous-scaled wire-length l ( lUt n, where l is the wirelength, Ut is friction velocity and n is kinematic viscosity). These competing factors can explain much of the disparity in existing literature, in particular explaining how previous studies have incorrectly concluded that the inner-scaled near-wall peak is independent of Re. We also investigate the appearance of the, so-called, ‘outerpeak’ in the broadband streamwise intensity, found by some researchers to occur within the log-region of high Reynolds number boundary layers. We show that this ‘outer-peak’ is most likely a symptom of attenuation of small-scales due to large l . Fully mapped energy spectra, obtained with two different l , are presented to demonstrate this phenomena. The spatial attenuation resulting from wires with large l effectively filters small-scale fluctuations from the recorded signal

    Single production of charged gauge bosons from little Higgs models in association with top quark at the LHCLHC

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    In the context of the little Higgs models, we discuss single production of the new charged gauge bosons in association with top quark at the CERNCERN Large Hadron Collider(LHC)(LHC). We find that the new charged gauge bosons WHW_{H}^{-} and XX^{-}, which are predicted by the littlest Higgs model and the SU(3) simple model, respectively, can be abundantly produced at the LHCLHC. However, since the main backgrounds coming from the processes ppttˉ+Xpp\to t\bar{t}+X and pptW+Xpp\to tW^{-}+X are very large, the values of the ratios NWN_{W} and NXN_{X} are very small in most of the parameter space. It is only possible to detect the signal of the gauge boson WHW_{H}^{-} via the process ppgb+XtWH+Xpp\to gb+X\to tW_{H}^{-}+X at the LHCLHC in a small region of the parameter space.Comment: 14pages, 4 figures. To be published in Europhysics Letter

    Noise Enhanced Stability in Fluctuating Metastable States

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    We derive general equations for the nonlinear relaxation time of Brownian diffusion in randomly switching potential with a sink. For piece-wise linear dichotomously fluctuating potential with metastable state, we obtain the exact average lifetime as a function of the potential parameters and the noise intensity. Our result is valid for arbitrary white noise intensity and for arbitrary fluctuation rate of the potential. We find noise enhanced stability phenomenon in the system investigated: the average lifetime of the metastable state is greater than the time obtained in the absence of additive white noise. We obtain the parameter region of the fluctuating potential where the effect can be observed. The system investigated also exhibits a maximum of the lifetime as a function of the fluctuation rate of the potential.Comment: 7 pages, 5 figures, to appear in Phys. Rev. E vol. 69 (6),200

    Realization of Circular Slot Frequency Selective Surfaces using Photoplotter and Wet Etching Technique for Terahertz Material Sensing Applications

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    This paper discusses on the analysis of band pass Frequency Selective Surfaces (FSS) for performance enhancement in material sensing application. Terahertz Spectroscopy has proved to be versatile tool for detection and sensing in measuring non-conductive materials. It is because most of the non-conductive materials have unique molecular resonance that may translate as transmission and absorption of signals within terahertz range. However, the most critical issue in detection and sensing is to improve its sensitivity therefore an extremely low concentration material still can be able to be detected in THz band. Hence, in this paper, a circular slot is modeled on a planar structure of Rogers Duroid 5880LZ substrate with thickness of 508µm using Computer Simulation Technology (CST). The simulation generates a band pass response with transmission magnitude of 0.95 at 0.66THz. Furthermore, photoplotter and wet etching fabrication process is used for the realization of terahertz FSS. Simulated and measured transmission shows a good agreement between 0.5THz to 0.7THz as only 1% shifts in frequency between simulated and measured results. Besides that, the fabrication of circular FSS shows narrower measured bandwidth as compared to its simulated counterpart. Hence, with the limitation of the wet etching to produce micron size structure both simulation and measured result shows good agreement for all the critical issues in this study
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