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# wave reflection

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#1
A Constantin
For more than two centuries progress in the study of water waves proved to be interdependent with innovative and deep developments in theoretical and experimental directions of investigation. In recent years, considerable progress has been achieved towards the understanding of waves of large amplitude. Within this setting one cannot rely on linear theory as nonlinearity becomes an essential feature. Various analytic methods have been developed and adapted to come to terms with the challenges encountered in settings where approximations (such as those provided by linear or weakly nonlinear theory) are ineffective...
January 28, 2018: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
#2
Simon Fryer, Keeron Stone, Tabitha Dickson, James Faulkner, Danielle Lambrick, Pablo Corres, Lauren Jerred, Lee Stoner
BACKGROUND AND AIMS: Although it is well known that resistance training (RT) is beneficial for patients suffering from a variety of cardiovascular diseases, it remains underutilized as a rehabilitation tool as there is no reliable way to monitor the additional stress placed on the central organs. The current study aimed to determine between-day reliability of central haemodynamic indices using oscillometric pulse wave analysis (PWA) during progressive sub-maximal RT. METHODS: Nineteen healthy young males were tested on 3 different mornings in a fasted state...
December 5, 2017: Atherosclerosis
#3
Dawei Liu, Rong Qiang, Yunchen Du, Ying Wang, Chunhua Tian, Xijiang Han
A series of magnetic FeCo alloy/carbon composites have been successfully prepared through in situ pyrolysis of Prussian blue analogues (PBAs) with different Fe/Co ratios. The Fe/Co ratio can affect the crystalline phase, particle size, and magnetic property of the FeCo alloy particles, as well as the relative graphitization degree of the carbon frameworks. As a result, the electromagnetic functions of these composites will be highly associated with the Fe/Co ratio, where high Co content is beneficial to the formation of strong dielectric loss and moderate Co content can facilitate the magnetic loss...
December 6, 2017: Journal of Colloid and Interface Science
#4
Hiroya Nishikawa, Daigou Mochizuki, Hiroki Higuchi, Yasushi Okumura, Hirotsugu Kikuchi
We demonstrate reversible RGB-color photocontrol of a chiral nematic liquid crystal (N*LC) by using newly synthesized closed- and open-type chiral dopants. The photoswitching elements in the dopants are azobenzene units on axially chiral binaphthyl cores. Owing to cis-trans photoisomerization of the azobenzene units, both closed- and open-type compounds showed higher solubility, larger helical twisting power (HTP), and larger changes in HTP than conventional chiral dopants in host LCs. Thus, even at very low dopant concentrations, we successfully controlled the chirality of the induced helical structure of the N*LCs...
December 2017: ChemistryOpen
#5
Ziheng Zhou, Ke Chen, Junming Zhao, Ping Chen, Tian Jiang, Bo Zhu, Yijun Feng, Yue Li
The metasurfaces have recently been demonstrated to provide full control of the phase responses of electromagnetic (EM) wave scattering over subwavelength scales, enabling a wide range of practical applications. Here, we propose a comprehensive scheme for the efficient and flexible design of metasurface Salisbury screen (MSS) capable of absorbing the impinging EM wave in an ultra-wide frequency band. We show that properly designed reflective metasurface can be used to substitute the metallic ground of conventional Salisbury screen for generating diverse resonances in a desirable way, thus providing large controllability over the absorption bandwidth...
November 27, 2017: Optics Express
#6
Kihong Kim
We study the mode conversion and resonant absorption phenomena occurring in a slab of a stratified anisotropic medium, optical axes of which are tilted with respect to the direction of inhomogeneity, using the invariant imbedding theory of wave propagation. When the tilt angle is zero, mode conversion occurs if the longitudinal component of the permittivity tensor, which is the one in the direction of inhomogeneity in the non-tilted case, varies from positive to negative values within the medium, while the transverse component plays no role...
November 27, 2017: Optics Express
#7
Li Jiu-Sheng, Zhao Ze-Jiang, Yao Jian-Quan
In order to extend to 3-bit encoding, we propose notched-wheel structures as polarization insensitive coding metasurfaces to control terahertz wave reflection and suppress backward scattering. By using a coding sequence of "00110011…" along x-axis direction and 16 × 16 random coding sequence, we investigate the polarization insensitive properties of the coding metasurfaces. By designing the coding sequences of the basic coding elements, the terahertz wave reflection can be flexibly manipulated. Additionally, radar cross section (RCS) reduction in the backward direction is less than -10dB in a wide band...
November 27, 2017: Optics Express
#8
Anja S Knaupp, Sam Buckberry, Jahnvi Pflueger, Sue Mei Lim, Ethan Ford, Michael R Larcombe, Fernando J Rossello, Alex de Mendoza, Sara Alaei, Jaber Firas, Melissa L Holmes, Shalima S Nair, Susan J Clark, Christian M Nefzger, Ryan Lister, Jose M Polo
Somatic cell reprogramming into induced pluripotent stem cells (iPSCs) induces changes in genome architecture reflective of the embryonic stem cell (ESC) state. However, only a small minority of cells typically transition to pluripotency, which has limited our understanding of the process. Here, we characterize the DNA regulatory landscape during reprogramming by time-course profiling of isolated sub-populations of intermediates poised to become iPSCs. Widespread reconfiguration of chromatin states and transcription factor (TF) occupancy occurs early during reprogramming, and cells that fail to reprogram partially retain their original chromatin states...
December 7, 2017: Cell Stem Cell
#9
Ehsan Faridi, Maryam Moradi, Narges Ansari, Amir Hossein Baradaran Ghasemi, Amir Afshar, Seyed Majid Mohseni Armaki
The demonstration of biosensors based on the surface plasmon effect holds promise for future high-sensitive electrodeless biodetection. The combination of magnetic effects with surface plasmon waves brings additional freedom to improve sensitivity and signal selectivity. Stacking biosensors with two-dimensional (2-D) materials, e.g., graphene (Gr) and MoS2, can influence plasmon waves and facilitate surface physiochemical properties as additional versatility aspects. We demonstrate magnetoplasmonic biosensors through the detuning of surface plasmon oscillation modes affected by magnetic effect via the presence of the NiFe (Py) layer and different light absorbers of Gr, MoS2, and Au ultrathin layers in three stacks of Au/Py/M(MoS2, Gr, Au) trilayers...
December 2017: Journal of Biomedical Optics
#10
Haoran Yuan, Feng Yan, Chunyan Li, Chunling Zhu, Xitian Zhang, Yujin Chen
Herein we develop a facile strategy for fabricating nickel particle encapsulated in few-layer nitrogen-doped graphene supported by graphite carbon sheets as high-performance electromagnetic wave absorbing material. The obtained material exhibits sheet-like morphology with a lateral length ranging from hundred nanometers to 2 micrometer and a thickness of about 23 nm. Nickel nanoparticles with a diameter of approximately 20 nm were encapsulated in about 6 layers of nitrogen-doped graphene. As applied for electromagnetic absorbing material, the heteronanostructures exhibit excellent electromagnetic wave absorption property, superior to most EMW absorbing materials previously reported...
December 7, 2017: ACS Applied Materials & Interfaces
#11
Jinlong Zhang, Han Wu, Hongfei Jiao, Sven Schröder, Marcus Trost, Zhanshan Wang, Xinbin Cheng
Light scattering in quarter-wave high-reflection (QWHR) coatings with fully correlated interfaces was reduced by adding Fabry-Perot (FP) cavity structures on top of the multilayer. The properly designed FP cavity can induce destructive interference for fully correlated interfaces and reduce the scattering loss. Compared to QWHR coatings, adding one FP cavity could decrease the scattering at the near specular angles, and two FP cavities have the potential to reduce light scattering in a broad angular range. A low-scattering HR (LSHR) coating using two FP cavities has been realized to suppress light scattering...
December 1, 2017: Optics Letters
#12
Mohammad Reza Tavakol, Amirhossein Saba, Amir Jafargholi, Amin Khavasi
We propose a bidirectional terahertz (THz) spectrum splitter using a practically simple metamaterial structure consisting of rectangular grooves covered by graphene. Thanks to the graphene optoelectronic tunability and by adjusting the grooves width, this structure provides nearly 2π phase shift. At the same time, the reflection efficiency is acceptable throughout the phase shifts. We design each of the meta-atoms using a circuit model, and then we synthesize the final supercell based on the generalized Snell's law so that the structure reflects different frequency waves to totally different directions...
December 1, 2017: Optics Letters
#13
Yusuf Ziya Umul
The concept of reflectionless surface is put forth, and its reflection and transmission coefficients are determined by using the scattered geometrical optics fields of transmissive and perfectly electric conducting surfaces. The boundary condition of the surface is introduced. The scattering problem of plane waves by a reflectionless half-screen is studied. The solution is investigated numerically.
November 20, 2017: Applied Optics
#14
Chenquan Ni, Weiqing Gao, Xiangcai Chen, Li Chen, Yong Zhou, Wei Zhang, Jigang Hu, Meisong Liao, Takenobu Suzuki, Yasutake Ohishi
A numerical simulation of third-order cascaded Raman fiber laser based on tellurite fiber at the 2-5 μm waveband is presented. The Raman fiber laser can be optimized with the most suitable tellurite fiber length of 0.5-1.0 m and the most reasonable reflectivity of the third-order Stokes output FBG32 of 10%-20%. We demonstrate numerically that the third-order Stokes wave can reach the maximum average power of 45.2 W and the maximum optical conversion efficiency of 45.2%, corresponding to the FBG32 reflectivity of 10% and the tellurite fiber length of 0...
November 20, 2017: Applied Optics
#15
Hendrika M Schenk, Bertus F Jeronimus, Lian van der Krieke, Elisabeth H Bos, Peter de Jonge, Judith G M Rosmalen
OBJECTIVE: Allostatic load (AL) reflects the deteriorating influences of stress on the body, and comprises a selection of biological markers. AL is associated with negative life events, stress, and negative affect (NA), as well as poor health outcomes. However, whether AL is also associated with positive affect (PA) is not clear. The present study therefore explores the association between PA and AL, accounting for age, sex, NA, and health behaviors. METHODS: Data of 45,225 individuals from the first wave of the multi-disciplinary prospective population-based cohort study Lifelines were used...
December 5, 2017: Psychosomatic Medicine
#16
Luciana Besedovsky, Hong-Viet V Ngo, Stoyan Dimitrov, Christoph Gassenmaier, Rainer Lehmann, Jan Born
Sleep is essential for health. Slow wave sleep (SWS), the deepest sleep stage hallmarked by electroencephalographic slow oscillations (SOs), appears of particular relevance here. SWS is associated with a unique endocrine milieu comprising minimum cortisol and high aldosterone, growth hormone (GH), and prolactin levels, thereby presumably fostering efficient adaptive immune responses. Yet, whether SWS causes these changes is unclear. Here we enhance SOs in men by auditory closed-loop stimulation, i.e., by delivering tones in synchrony with endogenous SOs...
December 7, 2017: Nature Communications
#17
Marc P Waase, R Kannan Mutharasan, William Whang, Marco R DiTullio, John P DiFiori, Lisa Callahan, Jimmie Mancell, Dermot Phelan, Allan Schwartz, Shunichi Homma, David J Engel
Importance: While it is known that long-term intensive athletic training is associated with cardiac structural changes that can be reflected on surface electrocardiograms (ECGs), there is a paucity of sport-specific ECG data. This study seeks to clarify the applicability of existing athlete ECG interpretation criteria to elite basketball players, an athlete group shown to develop significant athletic cardiac remodeling. Objective: To generate normative ECG data for National Basketball Association (NBA) athletes and to assess the accuracy of athlete ECG interpretation criteria in this population...
December 6, 2017: JAMA Cardiology
#18
Daisuke Miyamoto, Daichi Hirai, Masanori Murayama
Sleep plays important roles in sensory and motor memory consolidation. Sleep oscillations, reflecting neural population activity, involve the reactivation of learning-related neurons and regulate synaptic strength and, thereby affect memory consolidation. Among sleep oscillations, slow waves (0.5-4 Hz) are closely associated with memory consolidation. For example, slow-wave power is regulated in an experience-dependent manner and correlates with acquired memory. Furthermore, manipulating slow waves can enhance or impair memory consolidation...
2017: Frontiers in Neural Circuits
#19
Masanori Tachikawa, Masahiko Watanabe, Masahiro Fukaya, Kazuhisa Sakai, Tetsuya Terasaki, Ken-Ichi Hosoya
Creatine is synthesized by S-adenosylmethionine:guanidinoacetate N-methyltransferase (GAMT), and the creatine/phosphocreatine shuttle system mediated by creatine kinase (CK) is essential for storage and regeneration of high-energy phosphates in cells. Although the importance of this system in brain development is evidenced by the hereditary nature of creatine deficiency syndrome, the spatiotemporal cellular expression patterns of GAMT in developing brain remain unknown. Here we show that two waves of high GAMT expression occur in developing mouse brain...
December 5, 2017: Neurochemical Research
#20
Thomas M Henderson, Carlos A Jimenez-Hoyos, Gustavo E Scuseria
The spin structure of wave functions is reflected in the magnetic structure of the one-particle density matrix. Indeed, for single determinants we can use either one to determine the other. In this work we discuss how one can simply examine the one-particle density matrix to faithfully determine whether the spin magnetization density vector field is collinear, coplanar, or noncoplanar. For single determinants, this test suffices to distinguish collinear determinants which are eigenfunctions of $\hat{S}_{\hat{n}}$ from noncollinear determinants which are not...
December 5, 2017: Journal of Chemical Theory and Computation
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