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Full-Text Articles in Physical Sciences and Mathematics
Average Mass Scan Of The Total Ion Chromatogram Versus Percentage Chemical Composition In Multivariate Statistical Comparison Of Complex Volatile Mixtures, Niko Radulovic, Polina Blagojevic, Danielle Skropeta
Average Mass Scan Of The Total Ion Chromatogram Versus Percentage Chemical Composition In Multivariate Statistical Comparison Of Complex Volatile Mixtures, Niko Radulovic, Polina Blagojevic, Danielle Skropeta
Danielle Skropeta
The analysis of complex volatile mixtures by gas chromatography-mass spectrometry (GC-MS) is a time-consuming process. It involves separation and identification of the components based on their retention times and fragmentation patterns, followed by determination of their relative percentages from integration of their peak areas. Herein we show that multivariate statistical analysis of the relative abundances of the m/z values obtained from the average mass scans (AMS) of the complex mixture is a faster and potentially more reliable method of assessing these mixtures. To achieve this, 15 model complex mixtures, were prepared comprising varying amounts of 10 different constituents. The AMS …
Effect Of Protein Stabilization On Charge State Distribution In Positive- And Negative Ion Electrospray Ionization Mass Spectra, Stephen J. Watt, Margaret Sheil, Jennifer L. Beck, Pavel Prosselkov, Gottfried Otting, Nicholas E. Dixon
Effect Of Protein Stabilization On Charge State Distribution In Positive- And Negative Ion Electrospray Ionization Mass Spectra, Stephen J. Watt, Margaret Sheil, Jennifer L. Beck, Pavel Prosselkov, Gottfried Otting, Nicholas E. Dixon
Professor Nick E Dixon
Changes in protein conformation are thought to alter charge state distributions observed in electrospray ionization mass spectra (ESI-MS) of proteins. In most cases, this has been demonstrated by unfolding proteins through acidification of the solution. This methodology changes the properties of the solvent so that changes in the ESI-MS charge envelopes from conformational changes are difficult to separate from the effects of changing solvent on the ionization process. A novel strategy is presented enabling comparison of ESI mass spectra of a folded and partially unfolded protein of the same amino acid sequence subjected to the same experimental protocols and conditions. …
A Study On The Charge-Discharge Mechanism Of Co3o4 As An Anode For The Li Ion Secondary Battery, Yong-Mook Kang, Min-Sang Song, Jin-Ho Kim, Hyun-Seok Kim, Min-Sik Park, Jai-Young Lee, Hua-Kun Liu, S X. Dou
A Study On The Charge-Discharge Mechanism Of Co3o4 As An Anode For The Li Ion Secondary Battery, Yong-Mook Kang, Min-Sang Song, Jin-Ho Kim, Hyun-Seok Kim, Min-Sik Park, Jai-Young Lee, Hua-Kun Liu, S X. Dou
Shi Xue Dou
Co3O4 has shown acceptable electrochemical properties as the anode material of Li secondary batteries. In detail, its capacity reached about 700 mAh/g, twice as high as graphite, and 93.4% of initial capacity was retained after 100 cycles. EIS (electrochemical impedance spectroscopy) analyses revealed that after the 1st cycle, the insertion or extraction of Li ions in Co3O4 can occur homogeneously and reversibly (randless-like behavior, homogeneous mixture: Co + Li2O (in the state of Li insertion), Co3O4 (in the state of Li extraction)). In fact, the coulombic efficiency of Co3O4 was almost 100% except for the 1st cycle. According to P. …
Ozone-Induced Dissociation On A Modified Tandem Linear Ion-Trap: Observations Of Different Reactivity For Isomeric Lipids, Berwyck Poad, Huong Pham, Michael Thomas, Jessica Hughes, J Campbell, Todd Mitchell, Stephen Blanksby
Ozone-Induced Dissociation On A Modified Tandem Linear Ion-Trap: Observations Of Different Reactivity For Isomeric Lipids, Berwyck Poad, Huong Pham, Michael Thomas, Jessica Hughes, J Campbell, Todd Mitchell, Stephen Blanksby
Berwyck L. J. Poad
Ozone-induced dissociation (OzID) exploits the gas-phase reaction between mass-selected lipid ions and ozone vapor to determine the position(s) of unsaturation. In this contribution, we describe the modification of a tandem linear ion-trap mass spectrometer specifically for OzID analyses wherein ozone vapor is supplied to the collision cell. This instrumental configuration provides spatial separation between mass-selection, the ozonolysis reaction, and mass-analysis steps in the OzID process and thus delivers significant enhancements in speed and sensitivity (ca. 30-fold). These improvements allow spectra revealing the double-bond position(s) within unsaturated lipids to be acquired within 1 s: significantly enhancing the utility of OzID in …
Photoelectron-Photofragment Coincidence Spectroscopy In A Cryogenically Cooled Linear Electrostatic Ion Beam Trap, Christopher J. Johnson, Ben B. Shen, Berwyck L. J Poad, Robert E. Continetti
Photoelectron-Photofragment Coincidence Spectroscopy In A Cryogenically Cooled Linear Electrostatic Ion Beam Trap, Christopher J. Johnson, Ben B. Shen, Berwyck L. J Poad, Robert E. Continetti
Berwyck L. J. Poad
A cryogenically cooled linear electrostatic ion beam trap for use in photoelectron-photofragment coincidence (PPC) spectroscopy is described. Using this instrument, anions created in cold, low-dutycycle sources can be stored for many seconds in a ∼20 K environment to cool radiatively, removing energetic uncertainties due to vibrationally excited precursor anions. This apparatus maintains a well-collimated beam necessary for high-resolution fragment imaging and the high experimental duty cycle needed for coincidence experiments. Ion oscillation is bunched and phase-locked to a modelocked laser, ensuring temporal overlap between ion bunches and laser pulses and that ions are intersected by the laser only when travelling …
Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu
Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu
Shulei Chou
Flexible, free-standing, paper-like, graphene-silicon composite materials have been synthesized by a simple, one-step, in-situ filtration method. The Si nanoparticles are highly encapsulated in a graphene nanosheet matrix. The electrochemical results show that graphene-Si composite film has much higher discharge capacity beyond 100 cycles (708 mAh g− 1) than that of the cell with pure graphene (304 mAh g− 1). The graphene functions as a flexible mechanical support for strain release, offering an efficient electrically conducting channel, while the nanosized silicon provides the high capacity.
Nanocrystalline Nio Hollow Spheres In Conjunction With Cmc For Lithium-Ion Batteries, Chao Zhong, Jiazhao Wang, Shulei Chou, Konstantin Konstantinov, Mokhlesur Rahman, Hua Liu
Nanocrystalline Nio Hollow Spheres In Conjunction With Cmc For Lithium-Ion Batteries, Chao Zhong, Jiazhao Wang, Shulei Chou, Konstantin Konstantinov, Mokhlesur Rahman, Hua Liu
Shulei Chou
Hollow spherical NiO particles were prepared using the spray pyrolysis method with different concentrations of precursor. The electrochemical properties of the NiO electrodes, which contained a new type of binder, carboxymethyl cellulose (CMC), were examined for comparison with NiO electrodes with polyvinylidene fluoride (PVDF) binder. The electrochemical performance of NiO electrodes using CMC binder was significantly improved. For the cell made from 0.3 mol L−1 precursor, the irreversible capacity loss between the first discharge and charge is about 43 and 24% for the electrode with PVDF and CMC binder, respectively. The cell with NiO–CMC electrode has a much higher discharge …
Free-Standing Single-Walled Carbon Nanotube/Sno2 Anode Paper For Flexible Lithium-Ion Batteries, Lukman Noerochim, Jia-Zhao Wang, Shulei Chou, David Wexler
Free-Standing Single-Walled Carbon Nanotube/Sno2 Anode Paper For Flexible Lithium-Ion Batteries, Lukman Noerochim, Jia-Zhao Wang, Shulei Chou, David Wexler
Shulei Chou
Free-standingsingle-walledcarbonnanotube/SnO2 (SWCNT/SnO2) anodepaper was prepared by vacuum filtration of SWCNT/SnO2 hybrid material which was synthesized by the polyol method. From field emission scanning electron microscopy and transmission electron microscopy, the CNTs form a three-dimensional nanoporous network, in which ultra-fine SnO2 nanoparticles, which had crystallite sizes of less than 5 nm, were distributed, predominately as groups of nanoparticles on the surfaces of singlewalled CNT bundles. Electrochemical measurements demonstrated that the anodepaper with 34 wt.% SnO2 had excellent cyclic retention, with the high specific capacity of 454 mAh g−1 beyond 100 cycles at a current …
Irradiation Si On Carbon Nanotube Paper As A Flexible Anode Material For Lithium-Ion Batteries, Shulei Chou, Mihail Ionescu, Jia-Zhao Wang, Brad Winton, Hua Liu
Irradiation Si On Carbon Nanotube Paper As A Flexible Anode Material For Lithium-Ion Batteries, Shulei Chou, Mihail Ionescu, Jia-Zhao Wang, Brad Winton, Hua Liu
Shulei Chou
Silicon single walled carbon nanotube composite paper was modified by low energy ion implantation using 5i to obtain a flexible composite paper. Raman and FE-SEM results show that structure of SWCNT could be destroyed by the implantation. Electrochemical measurements display that the implanted SI can improve the specific capacity and the reversible capacity of CNT paper. After 50 cycles, the specific capacity of 5Hmplanted CNT paper is 30 per cent higher than the pristine CNT.
Zno-Doped Lifepo4 Cathode Material For Lithium-Ion Battery Fabricated By Hydrothermal Method, Yemin Hu, Jun Yao, Zhe Zhao, Mingyuan Zhu, Ying Li, Hongming Jin, Huijun Zhao, Jiazhao Wang
Zno-Doped Lifepo4 Cathode Material For Lithium-Ion Battery Fabricated By Hydrothermal Method, Yemin Hu, Jun Yao, Zhe Zhao, Mingyuan Zhu, Ying Li, Hongming Jin, Huijun Zhao, Jiazhao Wang
Australian Institute for Innovative Materials - Papers
LiFePO4 particles doped with zinc oxide was synthesized via a hydrothermal route and used as cathode material for lithium-ion battery. Sample of preferable shape and structure was obtained by a concise and efficient process. ZnO doping into the LiFePO4 matrix was positively confirmed by the results of X-ray diffraction (XRD); high-resolution transmission electron microscopy (HRTEM); energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). LiFePO4 doped with ZnO tends to form nanometer-size and homogeneous particles, which can improve markedly the performance and stability of charge-discharge cycle. A specific discharge capacity of ZnO-doped LiFePO4 at 132.3 mAh g-1 was achieved, with …
Simply Mixed Commercial Red Phosphorus And Carbon Nanotube Composite With Exceptionally Reversible Sodium-Ion Storage, Wei-Jie Li, Shulei Chou, Jia-Zhao Wang, Hua-Kun Liu, S X. Dou
Simply Mixed Commercial Red Phosphorus And Carbon Nanotube Composite With Exceptionally Reversible Sodium-Ion Storage, Wei-Jie Li, Shulei Chou, Jia-Zhao Wang, Hua-Kun Liu, S X. Dou
Australian Institute for Innovative Materials - Papers
Recently, sodium ion batteries (SIBs) have been given intense attention because they are the most promising alternative to lithium ion batteries for application in renewable power stations and smart grid, owing to their low cost, their abundant natural resources, and the similar chemistry of sodium and lithium. Elemental phosphorus (P) is the most promising anode materials for SIBs with the highest theoretical capacity of 2596 mA h g-1, but the commercially available red phosphorus cannot react with Na reversibly. Here, we report that simply hand-grinding commercial microsized red phosphorus and carbon nanotubes (CNTs) can deliver a reversible capacity of 1675 …
Hollow Structured Li3vo4 Wrapped With Graphene Nanosheets In Situ Prepared By One-Pot Template-Free Method As An Anode For Lithium-Ion Batteries, Yi Shi, Jia-Zhao Wang, Shulei Chou, David Wexler, Hui-Jun Li, Kiyoshi Ozawa, Hua-Kun Liu, Yu-Ping Wu
Hollow Structured Li3vo4 Wrapped With Graphene Nanosheets In Situ Prepared By One-Pot Template-Free Method As An Anode For Lithium-Ion Batteries, Yi Shi, Jia-Zhao Wang, Shulei Chou, David Wexler, Hui-Jun Li, Kiyoshi Ozawa, Hua-Kun Liu, Yu-Ping Wu
Australian Institute for Innovative Materials - Papers
To explore good anode materials of high safety, high reversible capacity, good cycling, and excellent rate capability, a Li3VO4 microbox with wall thickness of 40 nm was prepared by a one-pot and template-free in situ hydrothermal method. In addition, its composite with graphene nanosheets of about six layers of graphene was achieved. Both of them, especially the Li3VO4/graphene nanosheets composite, show superior electrochemical performance to the formerly reported vanadium-based anode materials. The composite shows a reversible capacity of 223 mAh g−1 even at 20C (1C = 400 mAh g−1). After 500 cycles at 10C there is no evident capacity fading.
Simple Synthesis Of Yolk-Shelled Znco2o4 Microspheres Towards Enhancing The Electrochemical Performance Of Lithium-Ion Batteries In Conjunction With A Sodium Carboxymethyl Cellulose Binder, Jingfa Li, Jiazhao Wang, David Wexler, Dongqi Shi, Jianwen Liang, Hua-Kun Liu, Shenglin Xiong, Yitai Qian
Simple Synthesis Of Yolk-Shelled Znco2o4 Microspheres Towards Enhancing The Electrochemical Performance Of Lithium-Ion Batteries In Conjunction With A Sodium Carboxymethyl Cellulose Binder, Jingfa Li, Jiazhao Wang, David Wexler, Dongqi Shi, Jianwen Liang, Hua-Kun Liu, Shenglin Xiong, Yitai Qian
Australian Institute for Innovative Materials - Papers
Mixed metal oxides have been attracting more and more attention recently because of their advantages and superiorities, which can improve the electrochemical performance of single metal oxides. These advantages include structural stability, good electronic conductivity, and reversible capacity. In this work, uniform yolk-shelled ZnCo2O4 microspheres were synthesized by pyrolysis of ZnCo-glycolate microsphere precursors which were prepared via a simple refluxing route without any precipitant or surfactant. The formation process of the yolk-shelled microsphere structure during the thermal decomposition of ZnCo-glycolate is discussed, which is mainly based on the heterogeneous contraction caused by non-equilibrium heat treatment. The performances of the as-prepared …
Nanocomposites Of Silicon And Carbon Derived From Coal Tar Pitch: Cheap Anode Materials For Lithium-Ion Batteries With Long Cycle Life And Enhanced Capacity, Yun-Xiao Wang, Shulei Chou, Hua-Kun Liu, S X. Dou
Nanocomposites Of Silicon And Carbon Derived From Coal Tar Pitch: Cheap Anode Materials For Lithium-Ion Batteries With Long Cycle Life And Enhanced Capacity, Yun-Xiao Wang, Shulei Chou, Hua-Kun Liu, S X. Dou
Australian Institute for Innovative Materials - Papers
From energy and environmental consideration, an industrial waste product, coal tar pitch (CTP), is used as the carbon source for Si/AC composite. We exploited a facile sintering method to largely scale up Si/amorphous carbon nanocomposite. The composites with 20 wt.% silicon with PVdF binder exhibited stable lithium storage ability for prolonged cycling. The composite anode delivered a capacity of 400.3 mAh g−1 with a high capacity retention of 71.3% after 1000 cycles. Various methods are used to investigate the reason for the outstanding cyclability. The results indicate that the silicon nanoparticles are wrapped by amorphous SiOx and AC in Si/AC …
Applications Of Voltammetric Ion Selective Electrodes To Complex Matrices, Alexander R. Harris, Jie Zhang, Robert W. Cattrall, Alan M. Bond
Applications Of Voltammetric Ion Selective Electrodes To Complex Matrices, Alexander R. Harris, Jie Zhang, Robert W. Cattrall, Alan M. Bond
Australian Institute for Innovative Materials - Papers
The practical application of two different voltammetric ion selective electrodes (VISE) to measure ion activity in complex solutions has been explored. 7,7,8,8-tetracyanoquinodimethane (TCNQ) and tetrathiafulvalene (TTF) microcrystals adhered to an electrode surface act as a low selectivity voltammetric ion sensor. Resistance drop effects and pH artifacts were minimised by the addition of an "innocent" supporting electrolyte (buffer) to the analyte solution. In this format, addition of an ionophore to improve selectivity resulted in a reduction in current magnitude, due to competition for the ion. In contrast, voltammetry of a thin film containing a redox active species, electrolyte, ionophore and membrane …
Limit Of Strong Ion Coupling Due To Electron Shielding, M. Lyon, Scott D. Bergeson, M. S. Murillo
Limit Of Strong Ion Coupling Due To Electron Shielding, M. Lyon, Scott D. Bergeson, M. S. Murillo
Faculty Publications
We show that strong coupling between ions in an ultracold neutral plasma is limited by electron screening. While electron screening reduces the quasiequilibrium ion temperature, it also reduces the ion-ion electrical potential energy. The net result is that the ratio of nearest-neighbor potential energy to kinetic energy in quasiequilibrium is constant and limited to approximately 1 unless the electrons are heated by some external source. We support these conclusions by reporting measurements of the ion velocity distribution in an ultracold neutral calcium plasma. These results match previously reported simulations of Yukawa systems. Theoretical considerations are used to determine the screened …