Online SOC Estimation Based on Simplified Electrochemical Model for Lithium-Ion Batteries Considering Current Bias

State of Charge (SOC) is essential for a smart Battery Management System (BMS). Traditional SOC estimation methods of lithium-ion batteries are usually conducted using battery equivalent circuit models (ECMs) and the impact of current sensor bias on SOC estimation is rarely considered. For this reason, this paper proposes an online SOC estimation based on a simplified electrochemical model (EM) for lithium-ion batteries considering sensor bias. In EM-based SOC estimation structure, the errors from the current sensor bias are addressed by proportional–integral observer. Then, the accuracy of the proposed EM-based SOC estimation is validated under different operating conditions. The results indicate that the proposed method has good performance and high accuracy in SOC estimation for lithium-ion batteries, which facilitates the on-board application in advanced BMS

Simultaneous Quantification of Ten Oxysterols Based on LC-MS/MS and its Application in Atherosclerosis Human Serum Samples

A highly sensitive and specific liquid chromatography-tandem mass spectrometric (LC-MS/MS) method has been developed and validated for the identification and relative quantification of ten oxysterols in human serum. After alkaline hydrolysis and derivatization, oxysterols in 50 mu L human serum were extracted and converted to corresponding picolinyl ester derivatives. The freshly prepared samples were analyzed by LC-MS/MS in high efficiency; and these ten oxysterols were separated within 11min. The method enabled the determination of standards with limits of detection between 0.0048 and 0.14ng/mL. The variances between sample preparations and measurements by this method were 3.28-8.47% and 2.01-7.26%, respectively. Recoveries of the oxysterols and cholesterol ranged from 90.49 to 121.01%, with the mean recovery of 102.63%. The rapid LC-MS/MS method enables relative quantification of oxysterols in human serum under high-throughput conditions. Furthermore, the established method has been applied to analyze the content of ten oxysterols in serum of healthy people and atherosclerotic. The results showed that the levels of 25-hydroxycholesterol and cholestane-3 ss,5,6 ss-triol in patients were significantly different from healthy people. This current method might provide the opportunity for clinical application. [GRAPHICS]

Well-controlled wet etching of ZnO films using hydrogen peroxide solution

We propose hydrogen peroxide (H2O2) solution as a novel and promising etchant for ZnO thin film with well-controlled etching performances and enhanced ultraviolet (UV) luminescence, which is also facile, inexpensive and environmentally friendly. We have analyzed its etching mechanism and surface modification effect for ZnO. Using this etchant, fine patterns have been transferred to the ZnO single-crystal films with good fidelity. The etching performances have been comprehensively investigated using Raman spectroscopy, scanning electronic microscopy (SEM), atom force microscopy (AFM), surface profiler and photoluminescence (PL) spectrometer. The results have shown that ZnO films after the long-time etching exhibited linear etching rate, smooth profile and increased UV emission, which enables H2O2 solution as an excellent wet etchant for various ZnO-based optoelectronic devices. (C) 2013 Published by Elsevier B.V

Temperature-dependent structural relaxation of BeZnO alloys

The thermal stability of BeZnO was examined in this study. Structural relaxation and reconstruction of the Be0.4Zn0.6O alloy film started at 500 degrees C and came to a halt at 800 degrees C. Be atoms were found to be diffused out from the host position, and BeO-based second phase was formed. The bandgap of Be0.4Zn0.6O was reduced to the value of pure ZnO after annealing at 600 degrees C. Therefore, the thermodynamic solubility of BeO in ZnO is far below than that of MgO in ZnO. Finally, the long term stability of BeZnO at room temperature was verified after aged for one year. (C) 2013 AIP Publishing LLC

Solar-blind wurtzite MgZnO alloy films stabilized by Be doping

MgxZn1-xO alloy films were deposited on c-plane sapphire substrates by radio frequency plasma-assisted molecular beam epitaxy (rf-PMBE). The phase segregation occurred when x was larger than 33%. Be doping was found experimentally able to stabilize the high-Mg-content MgZnO alloy. By alloying 1-2% Be into MgZnO, the band gap of as-prepared quaternary alloys can be raised to the solar-blind range (4.5 eV). Calculated formation energy of the alloys based on first principle reveals that a small amount of Be incorporation can reduce the formation energy of high-Mg-content MgZnO alloys and results in a more stable system, which justifies our experimental observations

Suppression of oxygen vacancies in Be alloyed ZnO

We report the suppression of oxygen vacancies (O-v) defects in BeO alloyed ZnO films. The alloy films are grown by plasma-assisted MBE on the sapphire substrates with a designed buffer layer. The decreased formation of O-v with the increase of Be content in BeZnO alloys is confirmed by the X-ray photoelectron spectroscopy and positron annihilation spectroscopy measurements. Hall measurements show a "V" curve of the electron concentration and a flip-over "V" curve of the electron mobility as a function of Be content. The turning points of both curves are for the samples prepared at T-Be = 960 degrees C. The turning points imply that there is a narrow growth window for optimum electrical properties of the BeZnO alloys, where the background electron density is almost one order of magnitude lower than the others, while the mobility is four times higher. The results on electrical properties are also supported by high-resolution XRD. (C) 2013 Elsevier B.V. All rights reserved

Formation behavior of BexZn1-xO alloys grown by plasma-assisted molecular beam epitaxy

We report the phase formation behavior of BexZn1-xO alloys grown by plasma-assisted molecular beam epitaxy. We find the alloy with low-and high-Be contents could be obtained by alloying BeO into ZnO films. X-ray diffraction measurements shows the c lattice constant value shrinks, and room temperature absorption shows the energy band-gap widens after Be incorporated. However, the alloy with intermediate Be composition are unstable and segregated into low-and high-Be contents BeZnO alloys. We demonstrate the phase segregation of BexZn1-xO alloys with intermediate Be composition resulted from large internal strain induced by large lattice mismatch between BeO and ZnO. (C) 2013 AIP Publishing LLC

ZnO film with ultra-low background electron concentration grown by plasma-assisted MBE using Mg film as the buffer layer

High quality ZnO epilayer with background electron concentration as low as 2.6 x 10(14) cm(-3) was obtained by plasma-assisted MBE on c-sapphire using a thin Mg film as the buffer layer. High-resolution XRD measurement shows a sharp (0 0 2) peak with full width at half maximum (FWHM) of only 0.029 degrees. Photoluminescence spectroscopy presents a weak defect-related near-edge emission. A metal-semiconductor-metal (MSM) typed photodetector based on the material demonstrates a response of similar to 43 A/W under the bias of 1 V and an ON/OFF ratio of 10(4). This un-doped ZnO with ultra-low background electron concentration could be a promising starting material for p-type doping. (c) 2012 Elsevier Ltd. All rights reserved