Themed issue: Optofluidics

The term optofluidics defines a growing research area that integrates optics and microfluidics in ways that enable unique strengths and advantages for a broad range of applications. The First International Conference on Optofluidics (Optofluidics- 2011) organized by Xi’an Jiaotong University and Lab on a Chip on 11–12 December 2011 featured work in this field, with an exciting two-day program of presentations and discussions. We are happy that Lab on a Chip, a major publication destination for optofluidic research, has scheduled this themed issue on Optofluidics. We are especially heartened that the optofluidics community has responded enthusiastically with a large number of excellent manuscript submissions

Self-Learning Hot Data Prediction: Where Echo State Network Meets NAND Flash Memories

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Well understanding the access behavior of hot data is significant for NAND flash memory due to its crucial impact on the efficiency of garbage collection (GC) and wear leveling (WL), which respectively dominate the performance and life span of SSD. Generally, both GC and WL rely greatly on the recognition accuracy of hot data identification (HDI). However, in this paper, the first time we propose a novel concept of hot data prediction (HDP), where the conventional HDI becomes unnecessary. First, we develop a hybrid optimized echo state network (HOESN), where sufficiently unbiased and continuously shrunk output weights are learnt by a sparse regression based on L2 and L1/2 regularization. Second, quantum-behaved particle swarm optimization (QPSO) is employed to compute reservoir parameters (i.e., global scaling factor, reservoir size, scaling coefficient and sparsity degree) for further improving prediction accuracy and reliability. Third, in the test on a chaotic benchmark (Rossler), the HOESN performs better than those of six recent state-of-the-art methods. Finally, simulation results about six typical metrics tested on five real disk workloads and on-chip experiment outcomes verified from an actual SSD prototype indicate that our HOESN-based HDP can reliably promote the access performance and endurance of NAND flash memories.Peer reviewe

Squeezed back-to-back correlation of \bqD^0{\bar \bqD}^0 in relativistic heavy-ion collisions

We investigate the squeezed back-to-back correlation (BBC) of $D^0\!{\bar D}^0$ in relativistic heavy-ion collisions, using the in-medium mass modification calculated with a self-energy in hot pion gas and the source space-time distributions provided by the viscous hydrodynamic code VISH2+1. It is found that the BBC of $D^0\!{\bar D}^0$ is significant in peripheral Au+Au collisions at the RHIC energy. A possible way to detect the BBC in experiment is presented.Comment: 4 pages, 5 figures, will be published in Chin. Phys. Let

Scheme for suppressing atom expansion induced contrast loss in atom interferometers

The loss of contrast due to atom expansion induced non-perfect Raman pulse area in atom interferometers is investigated systematically. Based on the theoretical simulation, we find that the expansion of the atomic cloud results in a decrease of the {\pi} pulse fidelity and a change of the {\pi} pulse duration, which lead to a significant reduction in fringe contrast. We propose a mitigation strategy of increasing the intensities of the second and third Raman pulses. Simulation results show that the fringe contrast can be improved by 13.6% in a typical atom interferometer gravimeter using this intensity compensation strategy. We also evaluate the effects of this mitigation strategy in the case of a lower atomic cloud temperature and a larger Raman beam size under different Raman pulse time interval conditions. This mitigation strategy has potential applications in increasing the sensitivity of atom interferometer-based precision measuring, including precision measuring of the gravity, gravity gradient, rotation, and magnetic field gradient, as well as testing of the Einstein equivalence principle.Comment: 14 pages, 8 figure