Browsing by Issue Date, starting with "2016-07-09"

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EFFECT OF SIZE AND STRETCH OF A MOVING FERROFLUID DROP ON INDUCED ELECTROMOTIVE FORCE
(2016-07-09)
Chen, Ching-Yao
;
Wang, Sheng-Yan
;
Wen, Chih-Yung
;
Jan, Cheng-Shiung
;
機械工程學系
Application for obtaining useful global features, e.g. the size and stretch of a moving ferrofluid drop by analyzing the characteristics of the induced electromotive force signal is demonstrated. These features are highly relevant to two maximum magnitudes in the electromotive force signal, e.g., the positive (V-1) and the negative (V-2) peak respectively induced when the drop enters and leaves the region covered by the induction coil. Favorable induction conditions of these two maximum magnitudes are opposite. In general, V-1 increases with the size of the ferrofluid drop because of stronger magnetization. On the contrary, V-2 is more prominent for a smaller drop, whose stretch is less significant. As a result, the ratio of vertical bar V-1/V-2 vertical bar monotonically increases with the, size of the ferrofluid drop. This finding suggests that the induced EMF signal can be used as a useful tool for quantifying the flow conditions, such as the size and stretch of moving ferrofluids.
Imagining Garage Start-Ups: Interactive Effects of Imaginative Capacities on Entrepreneurial Intention
(2016-07-09)
Chang, Chi-Cheng
;
Yao, Shu-Nung
;
Chen, Shi-An
;
King, Jung-Tai
;
Liang, Chaoyun
This article describes a structural examination of the interaction among different imaginative capacities and the entrepreneurial intention of electrical and computer engineering students. Two studies were combined to confirm the factor structure of survey items and test the hypothesised interaction model. The results indicated that imaginative capacity has 3 dimensions: conceiving, initiating, and transforming, whereas entrepreneurial intention comprises 2 factors: conviction and preparation. In addition, the results indicated that initiating imagination strongly affected entrepreneurial conviction and preparation; conceiving imagination positively predicted entrepreneurial conviction, whereas transforming imagination negatively predicted entrepreneurial preparation. The results also indicated that students possessing high, as well as those possessing low, conceiving and transforming imaginations demonstrated a high level of entrepreneurial preparation. In addition, an increase in transforming imagination increases the preparation of students possessing low initiating imagination and reduces the preparation of students possessing high initiating imagination. For developing a novel approach to conduct research on entrepreneurial intention and for discussing the practical implications of the findings, this study explicates alternative methods of cultivating students, promoting their interests, and enabling entrepreneurial behaviour in them by stimulating their imaginative capacities.
Stability of Einstein static state universe in the spatially flat branemodels
(2016-07-10)
Zhang, Kaituo
;
Wu, Puxun
;
Yu, Hongwei
;
Luo, Ling-Wei
;
物理研究所
With the assumption that a perfect fluid with a constant equation of state is the only energy component on the brane, we study the stability of Einstein static state solution under homogeneous and inhomogeneous scalar perturbations in both spatially flat Randall-Sundrum (RS) and Shtanov-Sahni (SS) braneworlds. We find that if the perfect fluid has a phantom-like property and the "Weyl fluid" originating from the projection of the bulk Weyl tensor onto the brane behaves like a radiation with positive energy density, the Einstein static state solution is stable in the SS braneworld, but unstable in the RS one. Furthermore, we demonstrate that the static state solution is also stable in the bulk with a timelike extra dimension. Thus, in the model where the extra dimension is timelike, our universe can stay at the Einstein static state past-eternally, which means that the big bang singularity might be resolved successfully by an emergent scenario. (C) 2016 The Authors. Published by Elsevier B.V.
THE INFRARED SPECTRUM OF PROTONATED OVALENE IN SOLID PARA-HYDROGEN AND ITS POSSIBLE CONTRIBUTION TO INTERSTELLAR UNIDENTIFIED INFRARED EMISSION
(2016-07-10)
Tsuge, Masashi
;
Bahou, Mohammed
;
Wu, Yu-Jong
;
Allamandola, Louis
;
Lee, Yuan-Pern
The mid-infrared emission from galactic objects, including reflection nebulae, planetary nebulae, proto-planetary nebulae, molecular clouds, etc, as well as external galaxies, is dominated by the unidentified infrared (UIR) emission bands. Large protonated polycyclic aromatic hydrocarbons (H(+)PAHs) were proposed as possible carriers, but no spectrum of an H(+)PAH has been shown to exactly match the UIR bands. Here, we report the IR spectrum of protonated ovalene (7-C32H15+) measured in a para-hydrogen (p-H-2) matrix at 3.2 K, generated by bombarding a mixture of ovalene and p-H-2 with electrons during matrix deposition. Spectral assignments were made based on the expected chemistry and on the spectra simulated with the wavenumbers and infrared intensities predicted with the B3PW91/6-311++G(2d, 2p) method. The close resemblance of the observed spectral pattern to that of the UIR bands suggests that protonated ovalene may contribute to the UIR emission, particularly from objects that emit Class A spectra, such as the IRIS reflection nebula, NGC 7023.
A penetrating atherosclerotic ulcer rupture in the ascending aorta with hemopericardium: a case report
(2016-07-11)
Liu, Yuan-Hao
;
Ke, Hung-Yen
;
Lin, Yi-Chang
;
Tsai, Chien-Sung
;
生物科技學系
Background: Acute aortic syndrome, including classic aortic dissection, intramural aortic hematoma, and penetrating atherosclerotic ulcer (PAU), is a term used to describe a group of conditions with similar clinical symptoms, but with different pathophysiological mechanisms. PAU is a lesion that penetrates the internal elastic lamina through the media. It is usually located in the descending aorta and rarely observed in the ascending aorta. Case presentation: A 76-year-old man with a history of essential hypertension was brought to the emergency department (ED) because of a sudden-onset chest pain at rest. He had not been taking his medication as ordered. His vital signs in the ED were a blood pressure of 82/60 mmHg, heart rate of 158 beats per min, respiratory rate of 22 breaths per min, and a body temperature of 37.2 degrees C. An electrocardiogram did not show an ST segment elevation, and cardiac enzymes were within normal limits. No widening mediastinum was found on chest radiography, but a large pericardial effusion with an impending cardiac tamponade was revealed on echocardiography. The diagnosis of PAU rupture in the ascending aorta with hemopericardium was made with chest computed tomography. An emergent sternotomy and ascending aorta reconstruction were performed. A ruptured ulcerative plaque through the intima to the adventitia without flap dissection in the ascending aorta was confirmed. The patient was discharged 18 days after the operation. Conclusions: Although PAU in the ascending aorta is uncommon, it is commonly lethal when it ruptures. With the current advances in endovascular techniques and devices, endovascular repair of PAU in the ascending aorta is currently recommended only for high-risk patients unsuitable for open repair. However, we anticipate that endovascular repair may become feasible in patients with PAU in the ascending aorta in the future.
Superconductivity in the two-dimensional electron gas induced by high-energy optical phonon mode and large polarization of the SrTiO3 substrate
(2016-07-11)
Rosenstein, Baruch
;
Shapiro, B. Ya.
;
Shapiro, I.
;
Li, Dingping
;
電子物理學系
Pairing in one-atomic-layer-thick two-dimensional electron gas (2DEG) by a single flat band of high-energy longitudinal optical phonons is considered. The polar dielectric SrTiO3 (STO) exhibits such an energetic phonon mode and the 2DEG is created both when one unit cell FeSe layer is grown on its (100) surface and on the interface with another dielectric like LaAlO3 (LAO). We obtain a quantitative description of both systems solving the gap equation for T-c for arbitrary Fermi energy is an element of(F), electron-phonon coupling lambda, and the phonon frequency Omega, and direct (random-phase approximation) electron-electron repulsion strength alpha. The focus is on the intermediate region between the adiabatic, is an element of(F) >> Omega, and the nonadiabatic, is an element of(F) << Omega, regimes. The high-temperature superconductivity in single-unit-cell FeSe/STO is possible due to a combination of three factors: high-longitudinal-optical phonon frequency, large electron-phonon coupling lambda similar to 0.5, and huge dielectric constant of the substrate suppression the Coulomb repulsion. It is shown that very low density electron gas in the interfaces is still capable of generating superconductivity of the order of 0.1 K in LAO/STO.
A Quantitative Method to Data Reuse Patterns of SIMT Applications
(2016-07-12)
Lai, Bo-Cheng Charles
;
Platero, Luis Garrido
;
Kuo, Hsien-Kai
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Understanding data reuse patterns of a computing system is crucial to effective design optimization. The emerging Single Instruction Multiple Threads (SIMT) processor adopts a programming model that is fundamentally disparate from conventional scalar processors. There is a lack of analytical approaches to quantify the data reuse of SIMT applications. This paper presents a quantitative method to study the data reuse inherent to SIMT applications. A metric, Data Reuse Degree, is defined to measure the amount of reused data between memory references, and associate each data reuse degree to a temporal distance representing the virtual time of the execution process. The experiments are performed on an abstracted SIMT processor that considers the programming model and runtime specifics. The experiments illustrate diverse data reuse patterns of SIMT applications and explore the impacts of architectural limitations.
Optical Properties of Plasmonic Mirror-Image Nanoepsilon
(2016-07-12)
Lin, Jia-Yu
;
Tsai, Chia-Yang
;
Lin, Pin-Tso
;
Hsu, Tse-En
;
Hsiao, Chi-Fan
We propose a novel mirror-image nanoepsilon (MINE) structure to achieve highly localized and enhanced near field at its gap and systematically investigate its plasmonic behaviors. The MINE can be regarded as a combination of two fundamental plasmonic nanostructures: a nanorod dimer and nanoring. By adapting a nanoring surrounding a nanorod dimer structure, the nanorod is regarded as a bridge pulling the charges from the nanoring to the nanorod, which induces stronger plasmon coupling in the gap to boost local near-field enhancement. Two resonance peaks are identified as the symmetric and anti-symmetric modes according to the symmetries of the charge distributions on the ring and rod dimer in the MINE. The symmetric mode in the MINE structure is preferred because its charge distribution leads to stronger near-field enhancement with a concentrated distribution around the gap. In addition, we investigate the influence of geometry on the optical properties of MINE structures by performing experiments and simulations. These results indicate that the MINE possesses highly tunable optical properties and that significant near-field enhancement at the gap region and rod tips can be realized by the gap and lightning-rod effects. The results improve understanding of such complex systems, and it is expected to guide and facilitate the design of optimum MINE structures for various plasmonic applications.
Tunable complex magnetic states of epitaxial core-shell metal oxide nanocrystals fabricated by the phase decomposition method
(2016-07-13)
Chang, S. J.
;
Lam, T. N.
;
Yang, C. Y.
;
Chen, Y. L.
;
Chu, Y. H.
We report on the successful fabrication of epitaxial-discrete CoxFe3-xO4/CoO magnetic nanostructures on a SrTiO3 substrate as well as the results of a thorough investigation of the magnetic cross-reactions of the two phases in the vicinity of the epitaxial junction. These nanostructures were originally prepared as Fe3O4-CoO core-shell structures through the phase decomposition of bismuth perovskite precursors by pulsed-laser deposition. An antiphase boundary emerged during the structural/electronic transition from the CoO core to the Co1-xFe2+XO4 shell; this then developed into a ferrimagnetic/antiferromagnetic interface. Uncompensated spins (UCS) arose from the CoxFe3-xO4/CoO interface as a result of strong ferrimagnetic-antiferromagnetic interactions. A notable exchange bias as well as a significant exchange enhancement was observed owing to the UCS, which had a locking effect because of the decoupling of the Co1-xFe2+XO4/CoO reversal from the antiphase boundary. Control of the precursor ratio allowed for the fine-tuning of the Co1-xFe2+XO4 phase and the associated locking behaviors. This, in turn, allowed the anisotropy and coercivity of the nanostructures to be manipulated. Thus, we were able to create and thoroughly understand a complex epitaxial configuration with tunable structural and magnetic properties. This study should open new opportunities with regard to current magnetic oxide technology, which requires novel methods for pursuing extremity of controllable properties over an atomic landscape.
Manifestations of Torsion-CH Stretch Coupling in the Infrared Spectrum of CH3OO
(2016-07-14)
Hsu, Kuo-Hsiang
;
Huang, Yu-Hsuan
;
Lee, Yuan-Pern
;
Huang, Meng
;
Miller, Terry A.
With a step-scan Fourier-transform spectrometer we recorded temporally resolved infrared absorption spectra of CH3OO radicals that were produced upon irradiation of CH3COCH3 and O-2 at 193 nm in a flowing mixture. At a resolution of 0.15 cm(-1), the rotational structure of the nu(2) band of CH3OO near 2954.4 cm(-1) is partially resolved and shows an unexpectedly broadened, and somewhat distorted, Q-branch. A 4D model Hamiltonian, consisting of three CH stretches and the methyl torsion, was developed to explore the origins of this broadening. The vibrational progressions predicted by the model Hamiltonian and the rotational contours of the nu(2) band, based on experimental ground-state rotational parameters and their values scaled by their calculated ratios for the upper state, produced simulations in satisfactory agreement with the observed spectrum. These results provide new inSight into the vibrational couplings in CH3OO.
Analysis of local bond-orientational order for liquid gallium at ambient pressure: Two types of cluster structures
(2016-07-14)
Chen, Lin-Yuan
;
Tang, Ping-Han
;
Wu, Ten-Ming
;
物理研究所
;
Institute of Physics
In terms of the local bond-orientational order ( LBOO) parameters, a cluster approach to analyze local structures of simple liquids was developed. In this approach, a cluster is defined as a combination of neighboring seeds having at least n(b) local-orientational bonds and their nearest neighbors, and a cluster ensemble is a collection of clusters with a specified n(b) and number of seeds n(s). This cluster analysis was applied to investigate the microscopic structures of liquid Ga at ambient pressure ( AP). The liquid structures studied were generated through ab initio molecular dynamics simulations. By scrutinizing the static structure factors ( SSFs) of cluster ensembles with different combinations of n(b) and n(s), we found that liquid Ga at AP contained two types of cluster structures, one characterized by sixfold orientational symmetry and the other showing fourfold orientational symmetry. The SSFs of cluster structures with sixfold orientational symmetry were akin to the SSF of a hard-sphere fluid. On the contrary, the SSFs of cluster structures showing fourfold orientational symmetry behaved similarly as the anomalous SSF of liquid Ga at AP, which is well known for exhibiting a high-q shoulder. The local structures of a highly LBOO cluster whose SSF displayed a high-q shoulder were found to be more similar to the structure of beta-Ga than those of other solid phases of Ga. More generally, the cluster structures showing fourfold orientational symmetry have an inclination to resemble more to beta-Ga. Published by AIP Publishing.
Vesicle electrohydrodynamic simulations by coupling immersed boundary and immersed interface method
(2016-07-15)
Hu, Wei-Fan
;
Lai, Ming-Chih
;
Seol, Yunchang
;
Young, Yuan-Nan
;
應用數學系
In this paper, we develop a coupled immersed boundary (IB) and immersed interface method (IIM) to simulate the electrodeformation and electrohydrodynamics of a vesicle in Navier-Stokes leaky dielectric fluids under a DC electric field. The vesicle membrane is modeled as an inextensible elastic interface with an electric capacitance and an electric conductance. Within the leaky dielectric framework and the piecewise constant electric properties in each fluid, the electric stress can be treated as an interfacial force so that both the membrane electric and mechanical forces can be formulated in a unified immersed boundary method. The electric potential and transmembrane potential are solved simultaneously via an efficient immersed interface method. The fluid variables in Navier-Stokes equations are solved using a projection method on a staggered MAC grid while the electric potential is solved at the cell center. A series of numerical tests have been carefully conducted to illustrate the accuracy and applicability of the present method to simulate vesicle electrohydrodynamics. In particular, we investigate the prolateoblate-prolate (POP) transition and the effect of electric field and shear flow on vesicle electrohydrodynamics. Our numerical results are in good agreement with those obtained in previous work using different numerical algorithms. (C) 2016 Elsevier Inc. All rights reserved.
學術界揭竿而起—楊芬瑩
(國立交通大學丘成桐中心, 2016-07-15)
楊芬瑩
推倒貪婪期刊付費高牆！
數理簡訊 PK 大戰與對局論
(國立交通大學丘成桐中心, 2016-07-15)
編輯室
零和賽局混合策略的精彩實例
M2M Encountering: Collaborative Localization via Instant Inter-Particle Filter Data Fusion
(2016-07-15)
Qiu, Jun-Wei
;
Tseng, Yu-Chee
;
資訊工程學系
;
Department of Computer Science
Much research has addressed indoor localization by integrating portable/wearable sensing and communication technologies. While GPS has dominated the outdoor environments, indoor localization schemes have to consider different observations, such as radio-frequency signals, vision or motions data, and apply data fusion to combine various sensor inputs. In this paper, we observe that when two devices meet up, which we call machine-to-machine (M2M) encountering, they can collaboratively calibrate each other\'s potential locations via M2M communications. We apply this technique to particle filter (PF), a common fusion technique, and show how to take the M2M encountering opportunities, which may happen frequently in crowded areas, to allow user devices to collaboratively calibrate their locations. Hence, the PF technique, which normally fuses observations from individual devices, is extended to an inter-PF, cross-device domain. We validate our inter-PF solution by simulations as well as a prototype system with smartphones and ZigBee infrastructure deployed in an office building. It is verified that the inter-PF helps converge the positioning results more rapidly, and improves location quality. Also, the proposed encountering mechanism has potential to be applied to other localization algorithms to improve their accuracy.
Targeted inactivation of murine Ddx3x: essential roles of Ddx3x in placentation and embryogenesis
(2016-07-15)
Chen, Chia-Yu
;
Chan, Chieh-Hsiang
;
Chen, Chun-Ming
;
Tsai, Yin-Shuan
;
Tsai, Tsung-Yuan
The X-linked DEAD-box RNA helicase DDX3 (DDX3X) is a multifunctional protein that has been implicated in gene regulation, cell cycle control, apoptosis, and tumorigenesis. However, the precise physiological function of Ddx3x during development remains unknown. Here, we show that loss of Ddx3x results in an early post-implantation lethality in male mice. The size of the epiblast marked by Oct3/4 is dramatically reduced in embryonic day 6.5 (E6.5) Ddx3x(-)/Y embryos. Preferential paternal X chromosome inactivation (XCI) in extraembryonic tissues of Ddx3x heterozygous (Ddx3x(-/+)) female mice with a maternally inherited null allele leads to placental abnormalities and embryonic lethality during development. In the embryonic tissues, Ddx3x exhibits developmental-and tissue-specific differences in escape from XCI. Targeted Ddx3x ablation in the epiblast leads to widespread apoptosis and abnormal growth, which causes embryonic lethality in the Sox2-cre/+; Ddx3x(flox)/Y mutant around E11.5. The observation of significant increases in gamma H2AX and p-p53(Ser15) indicates DNA damage, which suggests that loss of Ddx3x leads to higher levels of genome damage. Significant upregulation of p21(WAF1/Cip1) and p15(Ink4b) results in cell cycle arrest and apoptosis in Ddx3x-deficient cells. These results have uncovered that mouse Ddx3x is essential for both embryo and extraembryonic development.
L-p gradient estimate for elliptic equations with high-contrast conductivities in R-n
(2016-07-15)
Yeh, Li-Ming
;
應用數學系
;
Department of Applied Mathematics
Uniform estimate for the solutions of elliptic equations with high-contrast conductivities R-n is concerned. The space domain consists of a periodic connected sub-region and a periodic disconnected matrix block subset. The elliptic equations have fast diffusion in the connected sub-region and slow diffusion in the disconnected subset. Suppose epsilon is an element of (0, 1] is the diameter of each matrix block and omega(2) is an element of a (0, 1] is the conductivity ratio of the disconnected matrix block subset to the connected sub-region. It is proved that the W-1,W-p norm of the elliptic solutions in the connected sub-region is bounded uniformly in epsilon, is an element of, on when epsilon <= is an element of, the L-p norm of the elliptic solutions in the whole space is bounded uniformly in epsilon, omega; the W-1,W-p norm of the elliptic solutions in perforated domains is bounded uniformly in epsilon. However, the L-p norm of the second order derivatives of the solutions in the connected sub-region may not be bounded uniformly in epsilon, omega. (C) 2016 Elsevier Inc. All rights reserved.
數理簡訊格羅騰迪克的晚年手稿
(國立交通大學丘成桐中心, 2016-07-15)
編輯室
無恆產者的遺產之爭
數理簡訊英國三年拍了四部數學電影
(國立交通大學丘成桐中心, 2016-07-15)
編輯室
拉曼努真的故事《天才無限家》正上演
Targeted inactivation of murine Ddx3x: essential roles of Ddx3x in placentation and embryogenesis
(2016-07-15)
Chen, Chia-Yu
;
Chan, Chieh-Hsiang
;
Chen, Chun-Ming
;
Tsai, Yin-Shuan
;
Tsai, Tsung-Yuan
The X-linked DEAD-box RNA helicase DDX3 (DDX3X) is a multifunctional protein that has been implicated in gene regulation, cell cycle control, apoptosis, and tumorigenesis. However, the precise physiological function of Ddx3x during development remains unknown. Here, we show that loss of Ddx3x results in an early post-implantation lethality in male mice. The size of the epiblast marked by Oct3/4 is dramatically reduced in embryonic day 6.5 (E6.5) Ddx3x(-)/Y embryos. Preferential paternal X chromosome inactivation (XCI) in extraembryonic tissues of Ddx3x heterozygous (Ddx3x(-/+)) female mice with a maternally inherited null allele leads to placental abnormalities and embryonic lethality during development. In the embryonic tissues, Ddx3x exhibits developmental-and tissue-specific differences in escape from XCI. Targeted Ddx3x ablation in the epiblast leads to widespread apoptosis and abnormal growth, which causes embryonic lethality in the Sox2-cre/+; Ddx3x(flox)/Y mutant around E11.5. The observation of significant increases in gamma H2AX and p-p53(Ser15) indicates DNA damage, which suggests that loss of Ddx3x leads to higher levels of genome damage. Significant upregulation of p21(WAF1/Cip1) and p15(Ink4b) results in cell cycle arrest and apoptosis in Ddx3x-deficient cells. These results have uncovered that mouse Ddx3x is essential for both embryo and extraembryonic development.