Mi Shar Lu - Academia.edu (original) (raw)
Papers by Mi Shar Lu
Advances in the Diagnosis and Treatment of Sleep Apnea
Pulse oximeters are routinely used in various medical-grade and consumer-grade applications. They... more Pulse oximeters are routinely used in various medical-grade and consumer-grade applications. They can be used to estimate, for example, blood oxygen saturation, autonomic nervous system activity and cardiac function, blood pressure, sleep quality, and recovery through the recording of photoplethysmography signal. Medical-grade devices often record red and infra-red light-based photoplethysmography signals while smartwatches and other consumer-grade devices usually rely on a green light. At its simplest, a pulse oximeter can consist of one or two photodiodes and a photodetector attached, for example, a fingertip or earlobe. These sensors are used to record light absorption in a medium as a function of time. This time-varying absorption information is used to form a photoplethysmography signal. In this chapter, we discuss the working principles of pulse oximeters and the formation of the photoplethysmography signal. We will further discuss the advantages and disadvantages of pulse oxi...
In this paper, we present a Mesh-Connected Computer algorithm to construct the Voronoi diagram of... more In this paper, we present a Mesh-Connected Computer algorithm to construct the Voronoi diagram of a set of planar points. Given a set of n planar points our algorithm constructs a Voronoi diagram on an O (√n x √n) MCC with the constant storage per processer in O(√n log n) time. Using the Voronoi diagram, the problem of determining the nearest neighbor between two sets and constructing the Euclidean minimum spanning trees can be solved with the same time complexity on the MCC. The best sequential algorithms for constructing the Voronoi diagram have an optimal O(n log n) time complexity. Previous known parallel algorithm for this problem requires O(log<sup>3</sup>n) time on a Parallel Random Access Machine and O(log<sup>4</sup>n) time on the Cube-Connected-cycles with O(log n) storage per PE.
Membranes, Jan 12, 2018
Surface wettability-tailored porous ceramic/metallic membranes (in the tubular and planar disc fo... more Surface wettability-tailored porous ceramic/metallic membranes (in the tubular and planar disc form) were prepared and studied for both vapor-phase separation and liquid pervaporative separations of water-ethanol mixtures. Superhydrophobic nanoceramic membranes demonstrated more selective permeation of ethanol (relative to water) by cross-flow pervaporation of liquid ethanol⁻water mixture (10 wt % ethanol feed at 80 °C). In addition, both superhydrophilic and superhydrophobic membranes were tested for the vapor-phase separations of water⁻ethanol mixtures. Porous inorganic membranes having relatively large nanopores (up to 8-nm) demonstrated good separation selectivity with higher permeation flux through a non-molecular-sieving mechanism. Due to surface-enhanced separation selectivity, larger nanopore-sized membranes (~5⁻100 nm) can be employed for both pervaporation and vapor phase separations to obtain higher selectivity (e.g., permselectivity for ethanol of 13.9 during pervaporati...
Chemical communications (Cambridge, England), Jan 24, 2018
Surface phase heterogeneity within a fully charged LiCoO2 (LCO) composite electrode before and af... more Surface phase heterogeneity within a fully charged LiCoO2 (LCO) composite electrode before and after thermal decomposition has been shown to strongly depend on the distribution of the binder and carbon additives, but be independent of the crystalline facet and size of LCO, as revealed by X-ray photoemission electron microscopy (X-PEEM). The obtained new insights deepen the understanding of thermal stability in a real composite electrode, which would be valuable for further development of long-life and safe cathodes for lithium-ion batteries.
![Research paper thumbnail of {"__content__"=>"Unexpected phase separation in LiNiMnO within a porous composite electrode.", "sub"=>[{"__content__"=>"1-x"}, {"__content__"=>"0.5"}, {"__content__"=>"1.5"}, {"__content__"=>"4"}]}](https://attachments.academia-assets.com/103107350/thumbnails/1.jpg)
](Chemical communications (Cambridge, England), Jan 6, 2018
The Ni oxidation state in Li1-xNi0.5Mn1.5O4 (LNMO) within a composite electrode mapped by soft X-... more The Ni oxidation state in Li1-xNi0.5Mn1.5O4 (LNMO) within a composite electrode mapped by soft X-ray scanning transmission X-ray microscopy (STXM) has shown unexpected distinct variations in phase separation among and within individual battery particles, which has been experimentally correlated to both their morphology and interface structure for the first time. The obtained new insights will assist the further development of long-life high voltage LNMO batteries.
ACS applied materials & interfaces, Jan 2, 2017
The nanoscale interfacial inhomogeneity in a cycled large-format LiFePO4 (LFP) composite electrod... more The nanoscale interfacial inhomogeneity in a cycled large-format LiFePO4 (LFP) composite electrode has been studied by X-ray photoemission electron microscopy at single particle spatial resolution with a probe depth of ∼5 nm. The loss of active lithium in cycled LFP causes the coexsitence of fully delithiated LFP (FePO4) and partially delithiated LFP (Li0.6FePO4 or Li0.8FePO4) as a function of the extent of lithium loss. The distribution of various lithium loss phases along with local agglomeration of LFP and degradation of binder and carbon black are correlatively visualized. This is the first experimental exploration of chemical interplay between components in the composite electrode from a large-format battery, and implications on the LFP degradation in this battery are discussed.
Journal of Software, 2013
To meet the changes of internal and external environment, Enterprise Resources Planning (ERP) sys... more To meet the changes of internal and external environment, Enterprise Resources Planning (ERP) system needs to have a good flexibility. Flexibility is an indispensable request and is also a way that must be taken during the establishment process of ERP. Flexibility measurement is an important item for the implementation of ERP flexibility. According to the characteristics of ERP system, an index system for flexibility measurement of ERP system is presented with the interdependence and feedback relationships among criteria and/or indices being taken into account. Due to the vagueness and uncertainty information during the process of flexibility measurement, triangular fuzzy numbers are used to indicate the preference opinions of experts and decision makers. A flexibility measurement model of ERP system based on fuzzy analytic network process (FANP) is proposed. The local weights of criteria and indices are derived by fuzzy preference programming (FPP) method. An unweighted supermatrix based on the network structure of index system is developed, and the limit supermatrix is generated. The flexibility level of ERP system can be measured by the weights and scores of ERP. Finally, a case is given by the proposed method.
Journal of Service Science and Management, 2012
Dynamic alliance formations have increased dramatically over the past decade for its adaptation t... more Dynamic alliance formations have increased dramatically over the past decade for its adaptation to environmental change and market competition. However, many fail, while an even greater proportion perform poorly. The risk analysis of dynamic alliance will help enterprises to choose a coalition partner and make a reasonable benefit allocation plan. It's also good for reducing the risk and keeping the stability of the alliance. Based on the interaction and feedback relationships between criteria and/or indices, an index system for evaluating the risk of dynamic alliance is developed. With the information uncertainty and inaccuracy being considered, a new hybrid model based on fuzzy analytic network process (FANP) and fuzzy technique for order performance by similarity to ideal solution (TOPSIS) is proposed. The local weights of criteria and indices are obtained by fuzzy preference programming (FPP), and the comprehensive weights are derived by FANP. According to fuzzy TOPSIS, an optimal alternative is chosen by the closeness coefficient based on the shortest distance from the positive and the farthest distance from the negative ideal solutions. Finally, a numerical case is given by the proposed method.
Journal of Power Sources, 2007
In situ micro-FTIR spectroscopy was explored to characterize the solid-solid interface between li... more In situ micro-FTIR spectroscopy was explored to characterize the solid-solid interface between lithium electrode and polymer electrolytes. The cyclic voltammetric (CV) results indicated that the reduction reactions of oxygen and water as well as the formation of underpotential deposition (UPD) Li occur in the Li/PEO 20-LiN(CF 3 SO 2) 2 electrolyte interface in the different potential region. The infrared spectral changes observed during the CV process revealed that there is a direct correlation between the CV peaks and the magnitude of the infrared peaks. It is shown that the infrared reflectivity from the solid-solid interface is very sensitive to the formation of the passive layer on the lithium electrodes. The results obtained from optical micrographs also displayed directly the formation of the passive layer along with lithium deposition and dissolution process. It is correlated well with in situ FTIR and electrochemical experiments.
Journal of Parallel and Distributed Computing, 1988
Abstract In this paper, Mesh-Connected Computer (MCC) algorithms for computing several properties... more Abstract In this paper, Mesh-Connected Computer (MCC) algorithms for computing several properties of a set of, possibly intersecting rectangles are presented. Given a set of n iso-oriented rectangles, we describe MCC algorithms for determining the following properties: ...
Journal of Alloys and Compounds, 2011
A sphere-like carbon-coated Li 3 V 2 (PO 4) 3 composite was synthesized by carbothermal reduction... more A sphere-like carbon-coated Li 3 V 2 (PO 4) 3 composite was synthesized by carbothermal reduction method with two sessions of ball milling followed by spray-drying with the dispersant of polyethylene glycol added. The structure, particle size, and surface morphology of the cathode material were investigated via X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. Results indicate that the Li 3 V 2 (PO 4) 3 /C composite has a sphere-like morphology composed of a large number of carbon-coated ultrafine particles linked together with a monoclinic structure. In the voltage range of 3.0-4.3 V, it exhibits the discharge capacities of 130 mAh g −1 and 100 mAh g −1 at 0.2 C and 20 C rates, respectively. This behavior indicates that the obtained Li 3 V 2 (PO 4) 3 /C material has excellent rate capability.
Ionics, 2012
ABSTRACT The Li4Ti5O12/C composites were synthesized by a simple solid-state reaction at 800 °C f... more ABSTRACT The Li4Ti5O12/C composites were synthesized by a simple solid-state reaction at 800 °C for 12 h by using Super P® conductive carbon black as carbon source. X-ray diffraction analysis shows that the Li4Ti5O12 with 0, 5, 7.5, and 10 wt% carbon shows similar patterns with cubic spinel structure. Scanning electron microscope shows that Li4Ti5O12 aggregated seriously, but the aggregation was inhibited by the addition of Super P® carbon. The results indicate that the addition of 5 wt% carbon during sintering and a further 5 wt% carbon during slurry preparation shows the best rate capability of 110 mAh/g when the cells were charge/discharged at 10 C rate. The comparison of the charge–discharge curves shows that the higher rate improvement should further decrease the particle size of LTO or improve the conductivity of LTO itself.
Information Sciences, 1991
The paper presents mesh-connected computer (MCC) algorithms to solve the visibility problem for a... more The paper presents mesh-connected computer (MCC) algorithms to solve the visibility problem for a set of disjoint simple objects such as line segments, circles, and simple polygons in the plane. Given a set of n such objects, the algorithms compute, on a 6 x \/;;MCC, a view of these objects in Otfi) time. Both parallel and perspective views are considered. Earlier published algorithms for computing the views are sequential and have O(n log n) time complexity. Consider the solutions to solve problems of size n on MCCs with p processors, where p < n. An analysis is presented of the time performance and the limitations imposed by the computational and communication requirements, and the trade-offs between the size of the MCC and the time complexity that can be achieved.
Electrochimica Acta, 2010
A micron-sized LiFePO 4 /C composite with a spherical morphology was reduced carbothermally from ... more A micron-sized LiFePO 4 /C composite with a spherical morphology was reduced carbothermally from precursor particles prepared by ball milling-assisted spray-drying. The specific capacity of the electrode at a 10 C (1700 mA/g) rate was 110 mAh/g and a high voltage plateau was achieved. The high-rate performance of the composite electrode was due to its unique spherical structure, comprising clusters of nanoor sub-micron-sized spherical particles. This morphology increases the effective conductive surface area, reduces the charge-transfer reaction resistance and improves the diffusion of lithium ions.
Electrochimica Acta, 2011
ABSTRACT A spherical carbon-coated nano–micro structured LiFePO4 composite is synthesized for use... more ABSTRACT A spherical carbon-coated nano–micro structured LiFePO4 composite is synthesized for use as a cathode material in high-power lithium-ion batteries. The composites are synthesized through carbothermal reduction with two sessions of ball milling (before and after pre-sintering of precursor) followed by spray-drying with the dispersant of polyethylene glycol added. The structure, particle size, and surface morphology of the cathode active material and the properties of the coated carbon are investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. Results indicate that the LiFePO4/C composite has a spherical micro-porous morphology composed of a large number of carbon-coated nano-spheres linked together with an ordered olivine structure. The carbon on the surface of LiFePO4 effectively reduces inter-particle agglomeration of the LiFePO4 particles. A galvanostatic charge–discharge test indicates that the LiFePO4/C composites exhibit initial discharge capacities of 155 mAh g−1 and 88 mAh g−1 at 0.2 C and 20 C rates with the end of discharge voltage of 2.5 V, respectively. This behavior is ascribed to the unique spherical structure, which shortens lithium ions diffusion length and improves the electric contact between LiFePO4 particles.
Electrochimica Acta, 2008
The commercial lithium ion cells with LiCoO 2 as cathode, artificial graphite as anode and 1 M Li... more The commercial lithium ion cells with LiCoO 2 as cathode, artificial graphite as anode and 1 M LiPF 6 /EC-DEC-EMC (ethylene carbonate-diethyl carbonate-dimethyl carbonate) (1:1:1, v/v/v) with additives (1 wt.% vinylene carbonate (VC) + 1 wt.% propylene sulfite (PS)) as electrolyte were aged at 60% and 100% state of charge (SOC) for 6 months at room temperature and the corresponding cycle performance was measured. Charge/discharge results showed that the capacity retentions after 100 cycles were in the order of fresh cell >60% SOC > 100% SOC. The composition of SEI on the anode was analyzed by X-ray photoelectron spectroscopy (XPS) and the sulfur atom in PS was used as a tagged atom in XPS analysis. The results suggested that the transformation of organic species to inorganic species and the species containing sulfur atom from the reduction of PS was dissolved for the cells aged at 60% and 100% SOC. The SEM and XPS surface and depth profile analysis showed that the increase of the thickness of SEI layer and the variation of compositions on storage or cycling, is one of the most important reasons that results in the deterioration of the cycle performance of commercial lithium ion cells aged at 60% and 100% SOC at room temperature for 6 months.
Applied Mechanics and Materials, 2013
The weak signal, which is usually submerged in strong noise, is very difficult to detecte for its... more The weak signal, which is usually submerged in strong noise, is very difficult to detecte for its amplitude and frequency. The dynamic properties of VanderPol-Duffing are studied in this paper. Such system can go into the chaos under certain parameters. In chaotic state the disturbance of weak periodic signals can make the system dynamic behavior change dramatically. Our research results show that the system is from period doubling state to chaotic state when the amplitude of input signal is changed. And it has a remarkable impact influence on the system dynamic performance when the input frequency is varied. The unknown frequency can be detected through counting the numbers of turning point in phase diagram. The simulation results verified that the presented method is feasible and there are a lot of theory values in the research.
Applied Mechanics and Materials, 2012
The environment of the network is by Electronic, Mobile gets to Ubiquitous, has already been irre... more The environment of the network is by Electronic, Mobile gets to Ubiquitous, has already been irreversible trend, and the implementation of RFID technology had aroused discussion in a lot of fields. We think that the combination of RFID and Ubiquitous environment will cause another commercial revolution. Many industries had deployed RFID, like aviation industry, in which RFID is used in maintenance materials and baggage management. This paper discusses the implementation of RFID in Maintenance, Repair and Overhaul (MRO) process and the building of a ubiquitous computing environment. We believe that our proposal has three merits to MRO (1) anti-counterfeit parts (2) MRO liability (3) efficient and effective inspection. The architecture can address the competition pressure that aviation industry faces and consequently enhance competition advantages.
Applied Mechanics and Materials, 2014
We introduce a new across-peer rate allocation algorithm with successive refinement to improve th... more We introduce a new across-peer rate allocation algorithm with successive refinement to improve the video transmission performance in P2P networks, based on the combination of multiple description coding and network coding. Successive refinement is implemented through layered multiple description codes. The algorithm is developed to maximize the expected video quality at the receivers by partitioning video bitstream into different descriptions depending on different bandwidth conditions of each peer. Adaptive rate partition adjustment is applied to ensure the real reflection of the packet drop rate in the network. Also the granularity is changed to the scale of atomic blocks instead of stream rates in prior works. Through simulation results we show that the algorithm outperforms prior algorithms in terms of video playback quality at the peer ends, and helps the system more adjustable to the peer dynamics.
Advances in the Diagnosis and Treatment of Sleep Apnea
Pulse oximeters are routinely used in various medical-grade and consumer-grade applications. They... more Pulse oximeters are routinely used in various medical-grade and consumer-grade applications. They can be used to estimate, for example, blood oxygen saturation, autonomic nervous system activity and cardiac function, blood pressure, sleep quality, and recovery through the recording of photoplethysmography signal. Medical-grade devices often record red and infra-red light-based photoplethysmography signals while smartwatches and other consumer-grade devices usually rely on a green light. At its simplest, a pulse oximeter can consist of one or two photodiodes and a photodetector attached, for example, a fingertip or earlobe. These sensors are used to record light absorption in a medium as a function of time. This time-varying absorption information is used to form a photoplethysmography signal. In this chapter, we discuss the working principles of pulse oximeters and the formation of the photoplethysmography signal. We will further discuss the advantages and disadvantages of pulse oxi...
In this paper, we present a Mesh-Connected Computer algorithm to construct the Voronoi diagram of... more In this paper, we present a Mesh-Connected Computer algorithm to construct the Voronoi diagram of a set of planar points. Given a set of n planar points our algorithm constructs a Voronoi diagram on an O (√n x √n) MCC with the constant storage per processer in O(√n log n) time. Using the Voronoi diagram, the problem of determining the nearest neighbor between two sets and constructing the Euclidean minimum spanning trees can be solved with the same time complexity on the MCC. The best sequential algorithms for constructing the Voronoi diagram have an optimal O(n log n) time complexity. Previous known parallel algorithm for this problem requires O(log<sup>3</sup>n) time on a Parallel Random Access Machine and O(log<sup>4</sup>n) time on the Cube-Connected-cycles with O(log n) storage per PE.
Membranes, Jan 12, 2018
Surface wettability-tailored porous ceramic/metallic membranes (in the tubular and planar disc fo... more Surface wettability-tailored porous ceramic/metallic membranes (in the tubular and planar disc form) were prepared and studied for both vapor-phase separation and liquid pervaporative separations of water-ethanol mixtures. Superhydrophobic nanoceramic membranes demonstrated more selective permeation of ethanol (relative to water) by cross-flow pervaporation of liquid ethanol⁻water mixture (10 wt % ethanol feed at 80 °C). In addition, both superhydrophilic and superhydrophobic membranes were tested for the vapor-phase separations of water⁻ethanol mixtures. Porous inorganic membranes having relatively large nanopores (up to 8-nm) demonstrated good separation selectivity with higher permeation flux through a non-molecular-sieving mechanism. Due to surface-enhanced separation selectivity, larger nanopore-sized membranes (~5⁻100 nm) can be employed for both pervaporation and vapor phase separations to obtain higher selectivity (e.g., permselectivity for ethanol of 13.9 during pervaporati...
Chemical communications (Cambridge, England), Jan 24, 2018
Surface phase heterogeneity within a fully charged LiCoO2 (LCO) composite electrode before and af... more Surface phase heterogeneity within a fully charged LiCoO2 (LCO) composite electrode before and after thermal decomposition has been shown to strongly depend on the distribution of the binder and carbon additives, but be independent of the crystalline facet and size of LCO, as revealed by X-ray photoemission electron microscopy (X-PEEM). The obtained new insights deepen the understanding of thermal stability in a real composite electrode, which would be valuable for further development of long-life and safe cathodes for lithium-ion batteries.
Chemical communications (Cambridge, England), Jan 6, 2018
The Ni oxidation state in Li1-xNi0.5Mn1.5O4 (LNMO) within a composite electrode mapped by soft X-... more The Ni oxidation state in Li1-xNi0.5Mn1.5O4 (LNMO) within a composite electrode mapped by soft X-ray scanning transmission X-ray microscopy (STXM) has shown unexpected distinct variations in phase separation among and within individual battery particles, which has been experimentally correlated to both their morphology and interface structure for the first time. The obtained new insights will assist the further development of long-life high voltage LNMO batteries.
ACS applied materials & interfaces, Jan 2, 2017
The nanoscale interfacial inhomogeneity in a cycled large-format LiFePO4 (LFP) composite electrod... more The nanoscale interfacial inhomogeneity in a cycled large-format LiFePO4 (LFP) composite electrode has been studied by X-ray photoemission electron microscopy at single particle spatial resolution with a probe depth of ∼5 nm. The loss of active lithium in cycled LFP causes the coexsitence of fully delithiated LFP (FePO4) and partially delithiated LFP (Li0.6FePO4 or Li0.8FePO4) as a function of the extent of lithium loss. The distribution of various lithium loss phases along with local agglomeration of LFP and degradation of binder and carbon black are correlatively visualized. This is the first experimental exploration of chemical interplay between components in the composite electrode from a large-format battery, and implications on the LFP degradation in this battery are discussed.
Journal of Software, 2013
To meet the changes of internal and external environment, Enterprise Resources Planning (ERP) sys... more To meet the changes of internal and external environment, Enterprise Resources Planning (ERP) system needs to have a good flexibility. Flexibility is an indispensable request and is also a way that must be taken during the establishment process of ERP. Flexibility measurement is an important item for the implementation of ERP flexibility. According to the characteristics of ERP system, an index system for flexibility measurement of ERP system is presented with the interdependence and feedback relationships among criteria and/or indices being taken into account. Due to the vagueness and uncertainty information during the process of flexibility measurement, triangular fuzzy numbers are used to indicate the preference opinions of experts and decision makers. A flexibility measurement model of ERP system based on fuzzy analytic network process (FANP) is proposed. The local weights of criteria and indices are derived by fuzzy preference programming (FPP) method. An unweighted supermatrix based on the network structure of index system is developed, and the limit supermatrix is generated. The flexibility level of ERP system can be measured by the weights and scores of ERP. Finally, a case is given by the proposed method.
Journal of Service Science and Management, 2012
Dynamic alliance formations have increased dramatically over the past decade for its adaptation t... more Dynamic alliance formations have increased dramatically over the past decade for its adaptation to environmental change and market competition. However, many fail, while an even greater proportion perform poorly. The risk analysis of dynamic alliance will help enterprises to choose a coalition partner and make a reasonable benefit allocation plan. It's also good for reducing the risk and keeping the stability of the alliance. Based on the interaction and feedback relationships between criteria and/or indices, an index system for evaluating the risk of dynamic alliance is developed. With the information uncertainty and inaccuracy being considered, a new hybrid model based on fuzzy analytic network process (FANP) and fuzzy technique for order performance by similarity to ideal solution (TOPSIS) is proposed. The local weights of criteria and indices are obtained by fuzzy preference programming (FPP), and the comprehensive weights are derived by FANP. According to fuzzy TOPSIS, an optimal alternative is chosen by the closeness coefficient based on the shortest distance from the positive and the farthest distance from the negative ideal solutions. Finally, a numerical case is given by the proposed method.
Journal of Power Sources, 2007
In situ micro-FTIR spectroscopy was explored to characterize the solid-solid interface between li... more In situ micro-FTIR spectroscopy was explored to characterize the solid-solid interface between lithium electrode and polymer electrolytes. The cyclic voltammetric (CV) results indicated that the reduction reactions of oxygen and water as well as the formation of underpotential deposition (UPD) Li occur in the Li/PEO 20-LiN(CF 3 SO 2) 2 electrolyte interface in the different potential region. The infrared spectral changes observed during the CV process revealed that there is a direct correlation between the CV peaks and the magnitude of the infrared peaks. It is shown that the infrared reflectivity from the solid-solid interface is very sensitive to the formation of the passive layer on the lithium electrodes. The results obtained from optical micrographs also displayed directly the formation of the passive layer along with lithium deposition and dissolution process. It is correlated well with in situ FTIR and electrochemical experiments.
Journal of Parallel and Distributed Computing, 1988
Abstract In this paper, Mesh-Connected Computer (MCC) algorithms for computing several properties... more Abstract In this paper, Mesh-Connected Computer (MCC) algorithms for computing several properties of a set of, possibly intersecting rectangles are presented. Given a set of n iso-oriented rectangles, we describe MCC algorithms for determining the following properties: ...
Journal of Alloys and Compounds, 2011
A sphere-like carbon-coated Li 3 V 2 (PO 4) 3 composite was synthesized by carbothermal reduction... more A sphere-like carbon-coated Li 3 V 2 (PO 4) 3 composite was synthesized by carbothermal reduction method with two sessions of ball milling followed by spray-drying with the dispersant of polyethylene glycol added. The structure, particle size, and surface morphology of the cathode material were investigated via X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. Results indicate that the Li 3 V 2 (PO 4) 3 /C composite has a sphere-like morphology composed of a large number of carbon-coated ultrafine particles linked together with a monoclinic structure. In the voltage range of 3.0-4.3 V, it exhibits the discharge capacities of 130 mAh g −1 and 100 mAh g −1 at 0.2 C and 20 C rates, respectively. This behavior indicates that the obtained Li 3 V 2 (PO 4) 3 /C material has excellent rate capability.
Ionics, 2012
ABSTRACT The Li4Ti5O12/C composites were synthesized by a simple solid-state reaction at 800 °C f... more ABSTRACT The Li4Ti5O12/C composites were synthesized by a simple solid-state reaction at 800 °C for 12 h by using Super P® conductive carbon black as carbon source. X-ray diffraction analysis shows that the Li4Ti5O12 with 0, 5, 7.5, and 10 wt% carbon shows similar patterns with cubic spinel structure. Scanning electron microscope shows that Li4Ti5O12 aggregated seriously, but the aggregation was inhibited by the addition of Super P® carbon. The results indicate that the addition of 5 wt% carbon during sintering and a further 5 wt% carbon during slurry preparation shows the best rate capability of 110 mAh/g when the cells were charge/discharged at 10 C rate. The comparison of the charge–discharge curves shows that the higher rate improvement should further decrease the particle size of LTO or improve the conductivity of LTO itself.
Information Sciences, 1991
The paper presents mesh-connected computer (MCC) algorithms to solve the visibility problem for a... more The paper presents mesh-connected computer (MCC) algorithms to solve the visibility problem for a set of disjoint simple objects such as line segments, circles, and simple polygons in the plane. Given a set of n such objects, the algorithms compute, on a 6 x \/;;MCC, a view of these objects in Otfi) time. Both parallel and perspective views are considered. Earlier published algorithms for computing the views are sequential and have O(n log n) time complexity. Consider the solutions to solve problems of size n on MCCs with p processors, where p < n. An analysis is presented of the time performance and the limitations imposed by the computational and communication requirements, and the trade-offs between the size of the MCC and the time complexity that can be achieved.
Electrochimica Acta, 2010
A micron-sized LiFePO 4 /C composite with a spherical morphology was reduced carbothermally from ... more A micron-sized LiFePO 4 /C composite with a spherical morphology was reduced carbothermally from precursor particles prepared by ball milling-assisted spray-drying. The specific capacity of the electrode at a 10 C (1700 mA/g) rate was 110 mAh/g and a high voltage plateau was achieved. The high-rate performance of the composite electrode was due to its unique spherical structure, comprising clusters of nanoor sub-micron-sized spherical particles. This morphology increases the effective conductive surface area, reduces the charge-transfer reaction resistance and improves the diffusion of lithium ions.
Electrochimica Acta, 2011
ABSTRACT A spherical carbon-coated nano–micro structured LiFePO4 composite is synthesized for use... more ABSTRACT A spherical carbon-coated nano–micro structured LiFePO4 composite is synthesized for use as a cathode material in high-power lithium-ion batteries. The composites are synthesized through carbothermal reduction with two sessions of ball milling (before and after pre-sintering of precursor) followed by spray-drying with the dispersant of polyethylene glycol added. The structure, particle size, and surface morphology of the cathode active material and the properties of the coated carbon are investigated by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. Results indicate that the LiFePO4/C composite has a spherical micro-porous morphology composed of a large number of carbon-coated nano-spheres linked together with an ordered olivine structure. The carbon on the surface of LiFePO4 effectively reduces inter-particle agglomeration of the LiFePO4 particles. A galvanostatic charge–discharge test indicates that the LiFePO4/C composites exhibit initial discharge capacities of 155 mAh g−1 and 88 mAh g−1 at 0.2 C and 20 C rates with the end of discharge voltage of 2.5 V, respectively. This behavior is ascribed to the unique spherical structure, which shortens lithium ions diffusion length and improves the electric contact between LiFePO4 particles.
Electrochimica Acta, 2008
The commercial lithium ion cells with LiCoO 2 as cathode, artificial graphite as anode and 1 M Li... more The commercial lithium ion cells with LiCoO 2 as cathode, artificial graphite as anode and 1 M LiPF 6 /EC-DEC-EMC (ethylene carbonate-diethyl carbonate-dimethyl carbonate) (1:1:1, v/v/v) with additives (1 wt.% vinylene carbonate (VC) + 1 wt.% propylene sulfite (PS)) as electrolyte were aged at 60% and 100% state of charge (SOC) for 6 months at room temperature and the corresponding cycle performance was measured. Charge/discharge results showed that the capacity retentions after 100 cycles were in the order of fresh cell >60% SOC > 100% SOC. The composition of SEI on the anode was analyzed by X-ray photoelectron spectroscopy (XPS) and the sulfur atom in PS was used as a tagged atom in XPS analysis. The results suggested that the transformation of organic species to inorganic species and the species containing sulfur atom from the reduction of PS was dissolved for the cells aged at 60% and 100% SOC. The SEM and XPS surface and depth profile analysis showed that the increase of the thickness of SEI layer and the variation of compositions on storage or cycling, is one of the most important reasons that results in the deterioration of the cycle performance of commercial lithium ion cells aged at 60% and 100% SOC at room temperature for 6 months.
Applied Mechanics and Materials, 2013
The weak signal, which is usually submerged in strong noise, is very difficult to detecte for its... more The weak signal, which is usually submerged in strong noise, is very difficult to detecte for its amplitude and frequency. The dynamic properties of VanderPol-Duffing are studied in this paper. Such system can go into the chaos under certain parameters. In chaotic state the disturbance of weak periodic signals can make the system dynamic behavior change dramatically. Our research results show that the system is from period doubling state to chaotic state when the amplitude of input signal is changed. And it has a remarkable impact influence on the system dynamic performance when the input frequency is varied. The unknown frequency can be detected through counting the numbers of turning point in phase diagram. The simulation results verified that the presented method is feasible and there are a lot of theory values in the research.
Applied Mechanics and Materials, 2012
The environment of the network is by Electronic, Mobile gets to Ubiquitous, has already been irre... more The environment of the network is by Electronic, Mobile gets to Ubiquitous, has already been irreversible trend, and the implementation of RFID technology had aroused discussion in a lot of fields. We think that the combination of RFID and Ubiquitous environment will cause another commercial revolution. Many industries had deployed RFID, like aviation industry, in which RFID is used in maintenance materials and baggage management. This paper discusses the implementation of RFID in Maintenance, Repair and Overhaul (MRO) process and the building of a ubiquitous computing environment. We believe that our proposal has three merits to MRO (1) anti-counterfeit parts (2) MRO liability (3) efficient and effective inspection. The architecture can address the competition pressure that aviation industry faces and consequently enhance competition advantages.
Applied Mechanics and Materials, 2014
We introduce a new across-peer rate allocation algorithm with successive refinement to improve th... more We introduce a new across-peer rate allocation algorithm with successive refinement to improve the video transmission performance in P2P networks, based on the combination of multiple description coding and network coding. Successive refinement is implemented through layered multiple description codes. The algorithm is developed to maximize the expected video quality at the receivers by partitioning video bitstream into different descriptions depending on different bandwidth conditions of each peer. Adaptive rate partition adjustment is applied to ensure the real reflection of the packet drop rate in the network. Also the granularity is changed to the scale of atomic blocks instead of stream rates in prior works. Through simulation results we show that the algorithm outperforms prior algorithms in terms of video playback quality at the peer ends, and helps the system more adjustable to the peer dynamics.