Constrained Optimization Design of an Ion Focusing System with Wide Range of Energy Adjustment

For the study of ion scattering from solid surface, it is required that the energy of ions can be adjusted widely. The constrained optimization design of an ion focusing system with wide energy range and the magnification less than unity using the improved complex method is proposed in the present paper. This ion focusing system is suitable for use in the low energy ion scattering spectroscopy (ISS) and secondary ion mass spectroscopy (SIMS)

Intelligent PV Power Smoothing Control Using Probabilistic Fuzzy Neural Network with Asymmetric Membership Function

An intelligent PV power smoothing control using probabilistic fuzzy neural network with asymmetric membership function (PFNN-AMF) is proposed in this study. First, a photovoltaic (PV) power plant with a battery energy storage system (BESS) is introduced. The BESS consisted of a bidirectional DC/AC 3-phase inverter and LiFePO4 batteries. Then, the difference of the actual PV power and smoothed power is supplied by the BESS. Moreover, the network structure of the PFNN-AMF and its online learning algorithms are described in detail. Furthermore, the three-phase output currents of the PV power plant are converted to the dq-axis current components. The resulted q-axis current is the input of the PFNN-AMF power smoothing control, and the output is a smoothing PV power curve to achieve the effect of PV power smoothing. Comparing to the other smoothing methods, a minimum energy capacity of the BESS with a small fluctuation of the grid power can be achieved by the PV power smoothing control using PFNN-AMF. In addition, a personal computer- (PC-) based PV power plant emulator and BESS are built for the experimentation. From the experimental results of various irradiance variation conditions, the effectiveness of the proposed intelligent PV power smoothing control can be verified

Lasing on nonlinear localized waves in curved geometry

The use of geometrical constraints opens many new perspectives in photonics and in fundamental studies of nonlinear waves. By implementing surface structures in vertical cavity surface emitting lasers as manifolds for curved space, we experimentally study the impacts of geometrical constraints on nonlinear wave localization. We observe localized waves pinned to the maximal curvature in an elliptical-ring, and confirm the reduction in the localization length of waves by measuring near and far field patterns, as well as the corresponding dispersion relation. Theoretically, analyses based on a dissipative model with a parabola curve give good agreement remarkably to experimental measurement on the transition from delocalized to localized waves. The introduction of curved geometry allows to control and design lasing modes in the nonlinear regime.Comment: 6 pages, 6 figure

Comparison of MoS2, WS2, and Graphene Oxide for DNA Adsorption and Sensing

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Langmuir, © 2017 American Chemical Society after peer review and technical editing by publisher. To access the final edited and published work see Lu, C., Liu, Y., Ying, Y., & Liu, J. (2017). Comparison of MoS2, WS2, and Graphene Oxide for DNA Adsorption and Sensing. Langmuir, 33(2), 630–637. https://doi.org/10.1021/acs.langmuir.6b04502Interfacing DNA with two-dimensional (2D) materials has been intensely researched for various analytical and biomedical applications. Most of these studies have been performed on graphene oxide (GO) and two metal dichalcogenides, molybdenum disulfide (MoS2) and tungsten disulfide (WS2); all of them can all adsorb single-stranded DNA. However, they use different surface forces for adsorption based on their chemical structures. In this work, fluorescently labeled DNA oligonucleotides were used and their adsorption capacities and kinetics were studied as a function of ionic strength, DNA length, and sequence. Desorption of DNA from these surfaces was also measured. DNA is more easily desorbed from GO by various denaturing agents, whereas surfactants yield more desorption from MoS2 and WS2. Our results are consistent with the fact that DNA can be adsorbed by GO via pi-pi stacking and hydrogen bonding, and MoS, and WS2 mainly use van der Waals force for adsorption. Finally, fluorescent DNA probes were adsorbed by these 2D materials for detecting complementary DNA. For this assay, GO gave the highest sensitivity, whereas they all showed a similar detection limit. This study has enhanced our fundamental understanding of DNA adsorption by two important types of 2D materials and is useful for further rational optimization of their analytical and biomedical applications.Natural Sciences and Engineering Research Council of Canada (NSERC); Doctoral Fund for Priority Development Project from Ministry of Education of China [20120101130009

Tension Pneumoperitoneum Following Upper Gastrointestinal Endoscopy

Tension pneumoperitoneum is a potentially lethal complication of numerous iatrogenic procedures, including upper gastrointestinal (UGI) endoscopy. We report a 69-year-old man with UGI bleeding who developed tension pneumoperitoneum and cardiac arrest after UGI endoscopy. He was successfully resuscitated with needle decompression. Emergency surgery revealed a perforated gastric ulcer, and subtotal gastrectomy with Billroth II anastomosis was performed. Recovery was smooth and he was discharged from the hospital 18 days later. Tension pneumoperitoneum should be suspected in all patients who develop circulatory collapse with acutely distended abdomen after UGI endoscopy. Early identification relies on a high index of suspicion. Prompt treatment with needle decompression should not be delayed for confirmatory radiography once the clinical diagnosis is made