Experimental demonstration of SCMA for visible light communications

We propose an experimental demonstration of sparse code multiple access (SCMA) based visible light communications (VLC) system, in which the multi-dimensional codewords selected from a predefined codebook set are used to encode the transmitted data and a message passing algorithm (MPA) based multi-user receiver is used to detect the multiplexed codewords. Compared with the orthogonal frequency-division multiple access scheme, the SCMA scheme offers 150% overloading gain in the number of supported users at the cost of slightly decreased transmission performance

Effect of salidroside on ventricular remodeling after acute myocardial infarction

Purpose: To investigate the remodeling influence of salidroside (SAL) on the ventricles following acute myocardial infarction (AMI) in rats, and the processes involved.Methods: A total of 65 Sprague Dawley (SD) rats were assigned to 5 groups: sham (n = 13), model, and low-, medium- and high-dose SAL groups given SAL at doses of 12, 34, and 36 mg/day, respectively, with 13 rats in each group. Changes in pathological structure, collagen area, ratio of collagen I/collagen III, left ventricular mass index (LVW/BW), ratio of cardiac weight to body weight (HW/BW), creatine kinase MB isoenzyme (CK-MB), lactate dehydrogenase-1 (LDH-1), endothelin (ET), laminin (LN), and hyaluronic acid (HA) were evaluated. Expression levels of dishevelled-1 (DVL-1) and β-catenin in myocardial tissues of the rats were also determined.Results: The LVW/BW values were significantly higher in the low SAL and medium SAL groups than those in AMI rats, while the ratio of collagen I/III and expression levels of DVL-1 and β-catenin proteins were significantly lower than those in the model group (p < 0.05). The myocardial structure of rats in the sham group was normal, with no obvious lesions. The levels of CK-MB, LDH-1, ET, LN, and HA in medium and high-dose SAL groups were significantly lower than those in the model group (p < 0.05).Conclusion: Salidroside mitigates remodeling of ventricles following AMI in rats by modulating the Wnt/β-catenin signal route

Experimental demonstration of PAM-DWMT for passive optical network

We experimentally demonstrate a discrete wavelet multitone (DWMT) modulation scheme based on pulse amplitude modulation (PAM) for next generation passive optical network (PON), which offers high tolerance against chromatic dispersion, high spectral efficiency, low peak to average power ratio (PAPR) and low side lobes. The experimental results show the chromatic dispersion induced power penalties are negligible after 20km fiber transmission. Compared with orthogonal frequency division multiplexing (OFDM), DWMT offers a better receiver sensitivity

Structure and formation of anticyclonic eddies in the Iceland Basin

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of [publisher] for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 123 (2018): 5341-5359, doi:10.1029/2018JC013886.The Iceland Basin has the most energetic eddy activities in the subpolar North Atlantic. This study documents the structure for an anticyclonic eddy in the Iceland Basin using high‐resolution hydrographic and velocity observations. The eddy core waters have lens‐like structure with warm and salty features in the upper 1,000 m. The eddy distorts the density surface by doming the upper isopycnals and deepening the ones near the permanent pycnocline. The eddy has a diameter of about 120 km with substantial barotropic component in the velocity profiles. One branch of the North Atlantic Current in the central Iceland Basin is superimposed onto the eddy, leading to asymmetric velocity structure. Satellite maps show that eddy first shows up over the western slope of the Hatton Bank and moves westward to the central Iceland Basin. The waters enclosed in the eddy core share the same properties with Subpolar Mode Waters. Similar anticyclonic eddies are also found in high‐resolution numerical model simulations, which is used to explore eddy formation. The model results reveal that the potential vorticity gradient prior to the eddy event change signs in both horizontal and vertical directions. This potential vorticity gradient structure meets the necessary condition for the barotropic and baroclinic instabilities. Further calculation of the energy conversions suggests that eddies extract mean potential energy from the large‐scale isopycnal slope and gain the mean kinetic energy in the upper ocean. Therefore, both barotropic and baroclinic instabilities are involved to support the eddy growth.Fundamental Research Funds for the Central Universities Grant Numbers: 201362048, 201424001; China's National Key Research and Development Projects Grant Number: 2016YFA0601803; U.S. NSF Grant Numbers: OCE‐1634886, OCE‐1258823; Ocean University of China; Woods Hole Oceanographic Institution (WHOI)2019-02-0

Feature Spectrum Topology

Topology is a fundamental aspect of quantum physics, and it has led to key breakthroughs and results in various fields of quantum materials. In condensed matters, this has culminated in the recent discovery of symmetry-protected topological phases. However, symmetry-based topological characterizations rely heavily on symmetry analysis and are incapable of detecting the topological phases in systems where the symmetry is broken, thus missing a large portion of interesting topological physics. Here, we propose a new approach to understanding the topological nature of quantum materials, which we call feature spectrum topology. In this framework, the ground-state is separated into different partitions by the eigenspectrum of a feature, a particular chosen internal quantum degree of freedom, such as spin or pseudo-spin, and the topological properties are determined by analysis of these ground-state partitions. We show that bulk-boundary correspondence guarantees gapless spectral flows in either one of the energy or feature spectrum. Most importantly, such 'feature-energy duality' of gapless spectral flows serves as a fundamental manifestation of a topological phase, thereby paving a new way towards topological characterizations beyond symmetry considerations. Our development reveals the topological nature of a quantum ground state hidden outside symmetry-based characterizations, hence, providing a platform for a more refined search of unconventional topological materials