28,767 research outputs found
A new framework for optimization based-on Hybrid Swarm Intelligence
No full textPei-Wei Tsai, Jeng-Shyang Pan, Peng Shi, and Bin-Yih Lia
Evolution of the Magnetic Excitations in NaOsO3 through its Metal-Insulator Transition
Get PDFThe temperature dependence of the excitation spectrum in
NaOsO
3
through its metal-to-insulator transition (MIT) at 410 K has been investigated using resonant inelastic x-ray scattering at the Os
L
3
edge. High-resolution (
Δ
E
∼
56
meV
) measurements show that the well-defined, low-energy magnons in the insulating state weaken and dampen upon approaching the metallic state. Concomitantly, a broad continuum of excitations develops which is well described by the magnetic fluctuations of a nearly antiferromagnetic Fermi liquid. By revealing the continuous evolution of the magnetic quasiparticle spectrum as it changes its character from itinerant to localized, our results provide unprecedented insight into the nature of the MIT in
NaOsO
3
[J. G. Vale, S. Calder, C. Donnerer, D. Pincini, Y. G. Shi, Y. Tsujimoto, K. Yamaura, M. M. Sala, J. van den Brink, A. D. Christianson, and D. F. McMorrow, Phys. Rev. B 97, 184429 (2018)]
A Fast Self-Calibration Method for Piezoelectric Sensors Excited by Pseudorandom M-Sequence
Get PDFPiezoelectric element is the most critical component of a piezoelectric sensor, commonly applied for defect detection of electrical equipment. To ensure the sensor works stably and reliably, impedance and sensitivity response curves should be calibrated periodically with specific technical platforms in the laboratory to evaluate the sensor's performance and characteristics. This is costly, time-consuming, and inconvenient for industrial measurements. Pseudorandom M-sequence is a kind of binary signal that exhibits statistical characteristics similar to white noise. This article proposes a fast self-calibration method based on pseudorandom M-sequence, which is suitable for acquiring the impedance and sensitivity response curves of piezoelectric sensors. The clock pulse frequency of M-sequence can be adjusted to match the calibration band. The simulation and experimental results confirm that this method is feasible, reliable, and efficient in terms of both power and time consumption, requiring a few milliseconds and approximately 10 mW for a single calibration. The method was successfully applied in a commercial AE sensor and a recently developed wireless piezoelectric sensor. This work provides a novel solution for the self-calibration of smart piezoelectric sensors
A Multivariate Surface-Based Analysis of the Putamen in Premature Newborns: Regional Differences within the Ventral Striatum
Get PDFMany children born preterm exhibit frontal executive dysfunction, behavioral problems including attentional deficit/hyperactivity disorder and attention related learning disabilities. Anomalies in regional specificity of cortico-striato-thalamo-cortical circuits may underlie deficits in these disorders. Nonspecific volumetric deficits of striatal structures have been documented in these subjects, but little is known about surface deformation in these structures. For the first time, here we found regional surface morphological differences in the preterm neonatal ventral striatum. We performed regional group comparisons of the surface anatomy of the striatum (putamen and globus pallidus) between 17 preterm and 19 term-born neonates at term-equivalent age. We reconstructed striatal surfaces from manually segmented brain magnetic resonance images and analyzed them using our in-house conformal mapping program. All surfaces were registered to a template with a new surface fluid registration method. Vertex-based statistical comparisons between the two groups were performed via four methods: univariate and multivariate tensor-based morphometry, the commonly used medial axis distance, and a combination of the last two statistics. We found statistically significant differences in regional morphology between the two groups that are consistent across statistics, but more extensive for multivariate measures. Differences were localized to the ventral aspect of the striatum. In particular, we found abnormalities in the preterm anterior/inferior putamen, which is interconnected with the medial orbital/prefrontal cortex and the midline thalamic nuclei including the medial dorsal nucleus and pulvinar. These findings support the hypothesis that the ventral striatum is vulnerable, within the cortico-stiato-thalamo-cortical neural circuitry, which may underlie the risk for long-term development of frontal executive dysfunction, attention deficit hyperactivity disorder and attention-related learning disabilities in preterm neonates. © 2013 Shi et al
Preparation of (R)-2-chloro-1-(m-chlorophenyl)ethanol by Lipozyme TL IM-catalyzed second resolution
No full text(R)-2-Chloro-1-(m-chlorophenyl)ethanol, a precursor of (R)-3-chlorostyrene oxide which is the key chiral intermediate for the preparation of several beta 3-adrenergic receptor agonists was prepared in 40% yield and 99% ee by the Lipozyme TL IM-catalyzed second resolution of the corresponding racemate in the presence of vinyl acetate. (C) 2012 Shi Wen Xia. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved
User studies by driving simulators in the era of automated vehicle
Get PDFIn order to increase safety in the road and improve the user experience in the vehicle, the user studies have been conducted by researchers and practitioners in the automobile industry over the decades. Also, over time, the technology and design inside the car have changed and are leading to a faster, safer, and more comfortable user experience in driving, thanks to the results gained from the user studies. On the other side, the boosting automated driving technology gives new challenges to user studies in the validation of new technologies from the user’s perspective, improving the acceptance, employing the right usage, and so on. Laboratory driving simulation becomes one of the main methods for user studies because of its safety, ease of control, and precision in the scene restoration. In this paper, a typical fixed-base driving simulator will be introduced with a user interaction model in order to help the researchers to define the user study scope in each vehicle automation level and even predict the potential user study issues in the future autonomous vehicle technology and scenario. The strategy in the current study is to treat the different levels of automation in vehicles differently. Three case studies are provided accordingly from the low-automated to semi-autonomous driving and eventually fully autonomous driving. Each one addresses some of the critical points that should be paid attention to, in the user studies of the corresponding automation level, applying the previous model. In the low automation condition, the case study showed the effectiveness of the proposed method in the verification of olfactory modality interaction in the driver’s attention maintenance. The case study in the semi-automation condition demonstrated the capacity of the current method of capturing the user’s behavior changes in the take-over task, which is the most critical scenario in conditional autonomous driving. And the last case study showed the possibility to conduct comfort-related user studies in the full automation condition using the method, by monitoring the cognitive workload of users under different autonomous driving styles
Improved insulin sensitivity associated with reduced mitochondrial complex IV assembly and activity
Get PDFMice lacking Surf1, a complex IV assembly protein, have 50-70% reduction in cytochrome c oxidase activity in all tissues yet a paradoxical increase in lifespan. Here we report that Surf1-/- mice have lower body (15%) and fat (20%) mass, in association with reduced lipid storage, smaller adipocytes, and elevated indicators of fatty acid oxidation in white adipose tissue (WAT) compared with control mice. The respiratory quotient in the Surf1-/- mice was significantly lower than in the control animals (0.83- 0.93 vs. 0.90-0.98), consistent with enhanced fat utilization in Surf1-/- mice. Elevated fat utilization was associated with increased insulin sensitivity measured as insulinstimulated glucose uptake, as well as an increase in insulin receptor levels (2-fold) and glucose transporter type 4 (GLUT4; 1.3-fold) levels in WAT in the Surf1-/- mice. The expression of peroxisome proliferator- activated receptor β-coactivator 1 (PGC-1α) mRNA and protein was up-regulated by 2.5- and 1.9- fold, respectively, in WAT from Surf1-/- mice, and the expression of PGC-1α target genes and markers of mitochondrial biogenesis was elevated. Together, these findings point to a novel and unexpected link between reduced mitochondrial complex IV activity, enhanced insulin sensitivity, and increased mitochondrial biogenesis that may contribute to the increased longevity in the Surf1-/- mice.-Deepa, S. S., Pulliam, D., Hill, S., Shi, Y., Walsh, M. E., Salmon, A., Sloane, L., Zhang, N., Zeviani, M., Viscomi, C., Musi, N., Van Remmen, H. Improved insulin sensitivity associated with reduced mitochondrial complex IV assembly and activity. FASEB J. 27, 1371-1380 (2013). www.fasebj.org
Shi arrangements and low elements in Coxeter groups
Get PDFGiven an arbitrary Coxeter system and a nonnegative integer , the -Shi arrangement of is a subarrangement of the Coxeter hyperplane arrangement of . The classical Shi arrangement () was introduced in the case of affine Weyl groups by Shi to study Kazhdan-Lusztig cells for . As two key results, Shi showed that each region of the Shi arrangement contains exactly one element of minimal length in and that the union of their inverses form a convex subset of the Coxeter complex. The set of -low elements in were introduced to study the word problem of the corresponding Artin-Tits (braid) group and they turn out to produce automata to study the combinatorics of reduced words in .
In this article, we generalize and extend Shi\u27s results to any Coxeter system for any : (1) the set of minimal length elements of the regions in a -Shi arrangement is precisely the set of -low elements, settling a conjecture of the first and third authors in this case; (2) the union of the inverses of the (-)low elements form a convex subset in the Coxeter complex, settling a conjecture by the third author, Nadeau and Williams.44 pages, 7 figures; to appear in Proceedings of the London Mathematical Societ
Ultra-broadband wavelength conversion based on four-wave mixing in a Raman DFB fiber laser
No full textWe report highly efficient four-wave mixing (FWM) within a 30cm-long centre pi phase-shifted Raman DFB fiber laser with a continuous frequency tuning range of ~19.9 THz with the FWM conversion efficiency up to -25dB
Overview of Challa, V. R., Prasad, M. G., Shi, Y., and Fisher, F. T.’s 2008 Paper on a Vibration Energy Harvesting Device with Bidirectional Resonance Frequency Tunability
Get PDFOverview of Challa, V. R., Prasad, M. G., Shi, Y., and Fisher, F. T.’s 2008 Paper on a Vibration Energy Harvesting Device with Bidirectional Resonance Frequency Tunability
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