The Ti−45Nb(wt.%)alloy properties were investigated in relation to its potential biomedical use.Laser surface modification was utilized to improve its performance in biological systems.As a result of the laser treatme...The Ti−45Nb(wt.%)alloy properties were investigated in relation to its potential biomedical use.Laser surface modification was utilized to improve its performance in biological systems.As a result of the laser treatment,(Ti,Nb)O scale was formed and various morphological features appeared on the alloy surface.The electrochemical behavior of Ti−45Nb alloy in simulated body conditions was evaluated and showed that the alloy was highly resistant to corrosion deterioration regardless of additional laser surface modification treatment.Nevertheless,the improved corrosion resistance after laser treatment was evident(the corrosion current density of the alloy before laser irradiation was 2.84×10^(−8)A/cm^(2),while that after laser treatment with 5 mJ was 0.65×10^(−8)A/cm^(2))and ascribed to the rapid formation of a complex and passivating bi-modal surface oxide layer.Alloy cytotoxicity and effects of the Ti−45Nb alloy laser surface modification on the MRC-5 cell viability,morphology,and proliferation were also investigated.The Ti−45Nb alloy showed no cytotoxic effect.Moreover,cells showed improved viability and adherence to the alloy surface after the laser irradiation treatment.The highest average cell viability of 115.37%was attained for the alloy laser-irradiated with 15 mJ.Results showed that the laser surface modification can be successfully utilized to significantly improve alloy performance in a biological environment.展开更多
This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)f...This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)framework.Further with previous study,the uncertainty in capacity is considered as a non-negligible issue regarding multiple reasons,like the impact of weather,the strike of air traffic controllers(ATCOs),the military use of airspace and the spatiotemporal distribution of nonscheduled flights,etc.These recessive factors affect the outcome of traffic flow optimization.In this research,the focus is placed on the impact of sector capacity uncertainty on demand and capacity balancing(DCB)optimization and ATFM,and multiple options,such as delay assignment and rerouting,are intended for regulating the traffic flow.A scenario optimization method for sector capacity in the presence of uncertainties is used to find the approximately optimal solution.The results show that the proposed approach can achieve better demand and capacity balancing and determine perfect integer solutions to ATFM problems,solving large-scale instances(24 h on seven capacity scenarios,with 6255 flights and 8949 trajectories)in 5-15 min.To the best of our knowledge,our experiment is the first to tackle large-scale instances of stochastic ATFM problems within the collaborative ATFM framework.展开更多
The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2+and Zn was chemically plated on its surface through an immersion-reduction reaction. Such ...The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2+and Zn was chemically plated on its surface through an immersion-reduction reaction. Such Zn-deposited Al foil was quickly transferred into HCl-H 2 SO 4 solution for DC-etching. The effects of Zn impurity on the surface and cross-section etching morphologies and electrochemical behavior of Al foil were investigated by SEM, polarization curve (PC) and electrochemical impedance spectroscopy (EIS). The special capacitance of 100 V formation voltage of etched foil was measured. The results show that the chemical plating Zn on Al substrate in alkali solution can reduce the pitting corrosion resistance, enhance the pitting current density and improve the density and uniform distribution of pits and tunnels due to formation of the micro Zn-Al galvanic local cells. The special capacitance of etched foil grows with the increase of Zn2+concentration.展开更多
An innovative approach based on water environmental capacity for non-point source NPS pollution removal rate estimation was discussed by using both univariate and multivariate data analysis.Taking Shenzhen city as the...An innovative approach based on water environmental capacity for non-point source NPS pollution removal rate estimation was discussed by using both univariate and multivariate data analysis.Taking Shenzhen city as the study case a 67% to 74% NPS pollutant load removal rate can lead to meeting the chemical oxygen demand COD pollution control target for most watersheds.In contrast it is hardly to achieve the ammonia nitrogen NH4-N total phosphorus TP and biological oxygen demand BOD5 pollution control target by simply removing NPS pollutants. This highlights that the pollution control strategies should be taken according to different pollutant species and sources in different watersheds rather than one-size-fits-all .展开更多
Calcium phosphate coated Mg alloy was prepared. The phase constitute and surface morphology were identified and observed by X-ray diffractometer (XRD) and SEM. The results show that the coating is composed of flake-...Calcium phosphate coated Mg alloy was prepared. The phase constitute and surface morphology were identified and observed by X-ray diffractometer (XRD) and SEM. The results show that the coating is composed of flake-like CaHPO4-2H2O crystals. The corrosion resistance of the coated Mg alloy was measured by electrochemical polarization and immersion test in comparison with uncoated Mg alloy. Cytocompatibility was designed by observing the attachment, growth and proliferation of L929 cell on both coated and uncoated Mg alloy samples. The results display that the corrosion resistance of the coated Mg alloy is better than that of uncoated one. The immersion test also shows that the calcium phosphate coating can mitigate the corrosion of Mg alloy substrate, and tends to transform into hydroxyapatite (HA). Compared with uncoated Mg alloy, L929 cells exhibit good adherence, growth and proliferation characteristics on the coated Mg alloy, indicating that the cytocompatibility is significantly improved with the calcium phosphate coating.展开更多
The haemocompatibility of Ti-3Zr-2Sn-3Mo-25Nb biomedical alloy was studied after surface heparinization. A layer of sol-gel TiO2 films was applied on the alloy samples followed by active treatment in the bio-functiona...The haemocompatibility of Ti-3Zr-2Sn-3Mo-25Nb biomedical alloy was studied after surface heparinization. A layer of sol-gel TiO2 films was applied on the alloy samples followed by active treatment in the bio-functionalized solution for introducing the OH- and groups, and then the heparin was immobilized on the active TiO2 films through the electrostatic self assembly technology. It is shown that the heparinized films are mainly composed of anatase and rutile with smooth and dense surface. In vitro blood compatibility was evaluated by haemolysis test, clotting time and platelet adhesion behavior tests. The results show that the haemocompatibility of the alloy could be significantly improved by surface heparinization.展开更多
Li-rich layered transitional metal oxide Li1.2(Mn0.54Ni0.16Co0.08)O2 was prepared by sol-gel method and further modified by AlF3 coating via a wet process. The bare and AlF3-coated Li1.2(Mn0.54Ni0.16Co0.08)O2 samples ...Li-rich layered transitional metal oxide Li1.2(Mn0.54Ni0.16Co0.08)O2 was prepared by sol-gel method and further modified by AlF3 coating via a wet process. The bare and AlF3-coated Li1.2(Mn0.54Ni0.16Co0.08)O2 samples were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), and high resolution transmission electron microscope(HRTEM). XRD results show that the bare and AlF3-coated samples have typical hexagonal α-Na Fe O2 structure, and AlF3-coated layer does not affect the crystal structure of the bare Li1.2(Mn0.54Ni0.16Co0.08)O2. Morphology measurements present that the AlF3 layer with a thickness of 5-7 nm is coated on the surface of the Li1.2(Mn0.54Ni0.16Co0.08)O2 particles.Galvanostatic charge-discharge tests at various rates show that the AlF3-coated Li1.2(Mn0.54Ni0.16Co0.08)O2 has an enhanced electrochemical performance compared with the bare sample. At 1C rate, it delivers an initial discharge capacity of 208.2 m A·h/g and a capacity retention of 72.4% after 50 cycles, while those of the bare Li1.2(Mn0.54Ni0.16Co0.08)O2 are 191.7 m A·h/g and 51.6 %, respectively.展开更多
This letter adopts a GA (Genetic Algorithm) approach to assist in learning scaling of features that are most favorable to SVM (Support Vector Machines) classifier, which is named as GA-SVM. The relevant coefficients o...This letter adopts a GA (Genetic Algorithm) approach to assist in learning scaling of features that are most favorable to SVM (Support Vector Machines) classifier, which is named as GA-SVM. The relevant coefficients of various features to the classification task, measured by real-valued scaling, are estimated efficiently by using GA. And GA exploits heavy-bias operator to promote sparsity in the scaling of features. There are many potential benefits of this method:Feature selection is performed by eliminating irrelevant features whose scaling is zero, an SVM classifier that has enhanced generalization ability can be learned simultaneously. Experimental comparisons using original SVM and GA-SVM demonstrate both economical feature selection and excellent classification accuracy on junk e-mail recognition problem and Internet ad recognition problem. The experimental results show that comparing with original SVM classifier, the number of support vector decreases significantly and better classification results are achieved based on GA-SVM. It also demonstrates that GA can provide a simple, general, and powerful framework for tuning parameters in optimal problem, which directly improves the recognition performance and recognition rate of SVM.展开更多
The letter presents an improved two-dimensional linear discriminant analysis method for feature extraction. Compared with the current two-dimensional methods for feature extraction, the improved two-dimensional linear...The letter presents an improved two-dimensional linear discriminant analysis method for feature extraction. Compared with the current two-dimensional methods for feature extraction, the improved two-dimensional linear discriminant analysis method makes full use of not only the row and the column direc-tion information of face images but also the discriminant information among different classes. The method is evaluated using the Nanjing University of Science and Technology (NUST) 603 face database and the Aleix Martinez and Robert Benavente (AR) face database. Experimental results show that the method in the letter is feasible and effective.展开更多
This letter proposes an effective method for recognizing face images by combining two-Dimen- sional Principal Component Analysis (2DPCA) with IMage Euclidean Distance (IMED) method. The proposed method is comprised of...This letter proposes an effective method for recognizing face images by combining two-Dimen- sional Principal Component Analysis (2DPCA) with IMage Euclidean Distance (IMED) method. The proposed method is comprised of four main stages. The first stage uses the wavelet decomposition to extract low fre- quency subimages from original face images and omits the other three subimages. The second stage concerns the application of IMED to face images. In the third stage, 2DPCA is employed to extract the face features from the processed results in the second stage. Finally, Support Vector Machine (SVM) is applied to classify the extracted face features. Experimental results on the AR face image database show that the proposed method yields better recognition performance in comparison with the 2DPCA method that is not combined with IMED.展开更多
Four methods, including voltammetric measurement of double layer capacitance, surface oxides reduction, under potential deposition of Cu and carbon monoxide (CO) stripping have been applied to evaluate the real surf...Four methods, including voltammetric measurement of double layer capacitance, surface oxides reduction, under potential deposition of Cu and carbon monoxide (CO) stripping have been applied to evaluate the real surface area of a polycrystalline Pd (pc-Pd) electrode. The results reveal that the second and third methods lead to consistent results with deviations below 5%. And from the determined double layer capacitance and CO stripping charge, it is deduced that the double layer capacity unit area is 23.1±0.4μF/cm2 and the saturated CO adlayer should be ca. 0.66 ML in order to ensure that the real surface area as determined is consistent with the other two techniques. The applicability as well as the attentions when applying these techniques for the determination of the real surface area of pc-Pd electrodes have been discussed.展开更多
The interfacial compatibility of composite membrane is an important factor to its structural stability, andseparation performance. In this study, poly (ether sulfone) (PES) support layer was first hydrophilically ...The interfacial compatibility of composite membrane is an important factor to its structural stability, andseparation performance. In this study, poly (ether sulfone) (PES) support layer was first hydrophilically modified with poly(vinyl alcohol) (PVA) via surface segregation during the phase inversion process. Gelatin (GE) was then cast on the PVA-modified PES support layer as the active layer followed by crosslinking to fabricate composite membranes for ethanol dehydration. The enrichment of PVA on the surface of support layer improved interfacial compatibility of the as-prepared GE/PVA-PES composite membrane. The water contact angle measurement and X-ray photoelectron spectroscopy (XPS) data confirmed the surface segregation of PVA with a surface coverage density of -80%. T-peel test showed that the maxima/force to separate the support layer and the active layer was enhanced by 3 times compared with the GE/PES membrane. The effects of PVA content in the support layer, crosslinking of GE active layer and operating parameters on the pervaporative dehydration performance were investigated. The operational stability of the composite membrane was tested by immersing the membrane in ethanol aqueous solution for a period of time. Stable pervaporation performance for dehydration of 90% ethanol solution was obtained for GE/PVA-PES membrane with a separation factor of -60 and a permeation flux of -1910 g.m^-2.h1 without peeling over 28 days immersion.展开更多
The harsh space radiation environment compromises the reliability of an on-board switching fabric by leading to cross-point and switching element(SE)faults.Different from traditional faulttolerant switching fabrics on...The harsh space radiation environment compromises the reliability of an on-board switching fabric by leading to cross-point and switching element(SE)faults.Different from traditional faulttolerant switching fabrics only taking crosspoint faults into account,a novel Input and Output Parallel Clos network,referred to as the(p_1,p_2)-IOPClos,is proposed to tolerate both cross-point and SE faults.In the(p_1,p_2)-IOPClos,there are p_1 and p_2 expanded parallel switching planes in the input and output stages,respectively.The multiple input/output switching planes are interconnected through the middle stage to provide multiple paths in each stage by which the network throughput can be increased remarkably.Furthermore,the network reliability of the(p_1,p_2)-IOPClos under the above both kinds of faults is analyzed.The corresponding implementation cost is also presented along with the network size.Both theoretical analysis and numerical results indicate that the(p_1,p_2)-IOPClos outperforms traditional Clos-type networks at reliability,while has less implementation cost than the multi-plane Clos network.展开更多
The bamboo powder/polycaprolactone composites (BPPC) were prepared by torque-rheometer to investigate the effects of recipes and processing conditions on the theological properties of BPPC. The morphological behavio...The bamboo powder/polycaprolactone composites (BPPC) were prepared by torque-rheometer to investigate the effects of recipes and processing conditions on the theological properties of BPPC. The morphological behavior and mechanical properties of BPPC were also studied. Results showed that the optimum recipe for composite materials is composed of 70% of polycaprolactone, 30% of bamboo powder according to volume, 1.6 % of aluminate coupling agent, 1.2% of stearic acid, and 2% of paraffin to bamboo powder according to mass ratio The optimum processing condition parameters were determined as the rotational speed at 50 r-min^-1 and the temperature at 100℃ for BPPC. The BPPC (containing 30 copies bamboo powder) possessed eminent interfacial compatibility and mechanical properties of BPPC.展开更多
Sloshing phenomenon in a moving container is a complicated free surface flow problem. It has a wide range of engineering applications, especially in tanker ships and Liquefied Natural Gas (LNG) carriers. When the tank...Sloshing phenomenon in a moving container is a complicated free surface flow problem. It has a wide range of engineering applications, especially in tanker ships and Liquefied Natural Gas (LNG) carriers. When the tank in these vehicles is partially filled, it is essential to be able to evaluate the fluid dynamic loads on tank perimeter. Different geometric shapes such as rectangular, cylindrical, elliptical, spherical and circular conical have been suggested for ship storage tanks by previous researchers. In this paper a numerical model is developed based on incompressible and inviscid fluid motion for the liquid sloshing phenomenon. The coupled BEM-FEM is used to solve the governing equations and nonlinear free surface boundary conditions. The results are validated for rectangular container using data obtained for a horizontal periodic sway motion. Using the results of this model a new arrangement of trapezoidal shapes with quadratic sidewalls is suggested for tanker ship storage panels. The suggested geometric shape not only has a maximum surrounded tank volume to the constant available volume, but also reduces the sloshing effects more efficiently than the existing geometric shapes.展开更多
A nano-Li3V2(PO4)3/C powder was successfully prepared by a thermal polymerization method. The particle sizes of the intermediate product powder and the final product Li3V2(PO4)3 are all less than 200 nm. The carbo...A nano-Li3V2(PO4)3/C powder was successfully prepared by a thermal polymerization method. The particle sizes of the intermediate product powder and the final product Li3V2(PO4)3 are all less than 200 nm. The carbon is partially coated on the surface of Li3V2(PO4)3 particles and the rest exists between particles with a total carbon content of 4.6wt%. This nano-Li3V2(PO4)3/C sample shows a discharge capacity of 124 mAh/g with-out capacity fading after 100 cycles at 0.1 C in the voltage rang of 3.0-4.3 V. Excellent rate performance is also achieved with a capacity of 80 mAh/g at 20 C in 3.0-4.3 V and 100 mAh/g at 10 C in 3.0-4.8 V. This study suggests that the thermal polymerization method is suitable to synthesize nano-Li3V2(PO4)3/C materials.展开更多
According to the characteristics of the methane hydrate condensing and accumulating methane, authors put forward a new technique thought way to prevent the accident of coal and gas outburst by urging the methane in th...According to the characteristics of the methane hydrate condensing and accumulating methane, authors put forward a new technique thought way to prevent the accident of coal and gas outburst by urging the methane in the coal seams to form hydrate. The paper analyzes the feasibility of forming the methane hydrate in the coal seam from the several sides, such as, temperature,pressure, and gas components, and the primary trial results indicate the problems should be settled before the industrialization appliance realized.展开更多
In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator a...In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator and universal frequency to digital converter (UFDC). Due to variation in angular displacement in the variable area type capacitor which is connected in the timer based astable circuit,capacitance changes which in turn changes the time period of the timer circuit output. The time period of the timer output waveform is linear with the capacitance and hence linear with angular displacement. The timer output is further processed with UFDC for the measurement. The experimental results show that the time period is linear with the angular displacement in the range of 0- 180° and the uncertainty we should associate it with this average time period value is the standard deviation of the mean,often called the standard error (SE),which is ± 0.023 μs. Because of the simplicity,this measurement system can be used in both electronic and industrial instrumentation.展开更多
In this paper we describe the decomposition problem of a special kind of Ap,n,4p-5 polyhedra by using the associated matrices and their admissible operations.
基金the Ministry of Science,Technological Development and Innovation of the Republic of Serbia(No.451-03-47/2023-01/200017)the PhD fellowship of Slađana LAKETIĆ.Authors would also like to acknowledge the help of Dr.Anton HOHENWARTER from the Department of Materials Science,Montanuniversitat Leoben,Austria,during the Ti−45Nb alloy microstructural analysis.
文摘The Ti−45Nb(wt.%)alloy properties were investigated in relation to its potential biomedical use.Laser surface modification was utilized to improve its performance in biological systems.As a result of the laser treatment,(Ti,Nb)O scale was formed and various morphological features appeared on the alloy surface.The electrochemical behavior of Ti−45Nb alloy in simulated body conditions was evaluated and showed that the alloy was highly resistant to corrosion deterioration regardless of additional laser surface modification treatment.Nevertheless,the improved corrosion resistance after laser treatment was evident(the corrosion current density of the alloy before laser irradiation was 2.84×10^(−8)A/cm^(2),while that after laser treatment with 5 mJ was 0.65×10^(−8)A/cm^(2))and ascribed to the rapid formation of a complex and passivating bi-modal surface oxide layer.Alloy cytotoxicity and effects of the Ti−45Nb alloy laser surface modification on the MRC-5 cell viability,morphology,and proliferation were also investigated.The Ti−45Nb alloy showed no cytotoxic effect.Moreover,cells showed improved viability and adherence to the alloy surface after the laser irradiation treatment.The highest average cell viability of 115.37%was attained for the alloy laser-irradiated with 15 mJ.Results showed that the laser surface modification can be successfully utilized to significantly improve alloy performance in a biological environment.
文摘This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)framework.Further with previous study,the uncertainty in capacity is considered as a non-negligible issue regarding multiple reasons,like the impact of weather,the strike of air traffic controllers(ATCOs),the military use of airspace and the spatiotemporal distribution of nonscheduled flights,etc.These recessive factors affect the outcome of traffic flow optimization.In this research,the focus is placed on the impact of sector capacity uncertainty on demand and capacity balancing(DCB)optimization and ATFM,and multiple options,such as delay assignment and rerouting,are intended for regulating the traffic flow.A scenario optimization method for sector capacity in the presence of uncertainties is used to find the approximately optimal solution.The results show that the proposed approach can achieve better demand and capacity balancing and determine perfect integer solutions to ATFM problems,solving large-scale instances(24 h on seven capacity scenarios,with 6255 flights and 8949 trajectories)in 5-15 min.To the best of our knowledge,our experiment is the first to tackle large-scale instances of stochastic ATFM problems within the collaborative ATFM framework.
基金Project (51172102) supported by the National Natural Science Foundation of ChinaProject (BS2011CL011) supported by Promotive Research Fund for Young and Middle-aged Scientists of Shandong Province(doctor fund),China
文摘The Al foil for high voltage Al electrolytic capacitor usage was immersed in 5.0%NaOH solution containing trace amount of Zn2+and Zn was chemically plated on its surface through an immersion-reduction reaction. Such Zn-deposited Al foil was quickly transferred into HCl-H 2 SO 4 solution for DC-etching. The effects of Zn impurity on the surface and cross-section etching morphologies and electrochemical behavior of Al foil were investigated by SEM, polarization curve (PC) and electrochemical impedance spectroscopy (EIS). The special capacitance of 100 V formation voltage of etched foil was measured. The results show that the chemical plating Zn on Al substrate in alkali solution can reduce the pitting corrosion resistance, enhance the pitting current density and improve the density and uniform distribution of pits and tunnels due to formation of the micro Zn-Al galvanic local cells. The special capacitance of etched foil grows with the increase of Zn2+concentration.
基金The National Science and Technology Major Project of China(No.2012ZX07301-001)the Shenzhen Environmental Research Project,China Postdoctoral Science Foundation(No.2013M530642)
文摘An innovative approach based on water environmental capacity for non-point source NPS pollution removal rate estimation was discussed by using both univariate and multivariate data analysis.Taking Shenzhen city as the study case a 67% to 74% NPS pollutant load removal rate can lead to meeting the chemical oxygen demand COD pollution control target for most watersheds.In contrast it is hardly to achieve the ammonia nitrogen NH4-N total phosphorus TP and biological oxygen demand BOD5 pollution control target by simply removing NPS pollutants. This highlights that the pollution control strategies should be taken according to different pollutant species and sources in different watersheds rather than one-size-fits-all .
文摘Calcium phosphate coated Mg alloy was prepared. The phase constitute and surface morphology were identified and observed by X-ray diffractometer (XRD) and SEM. The results show that the coating is composed of flake-like CaHPO4-2H2O crystals. The corrosion resistance of the coated Mg alloy was measured by electrochemical polarization and immersion test in comparison with uncoated Mg alloy. Cytocompatibility was designed by observing the attachment, growth and proliferation of L929 cell on both coated and uncoated Mg alloy samples. The results display that the corrosion resistance of the coated Mg alloy is better than that of uncoated one. The immersion test also shows that the calcium phosphate coating can mitigate the corrosion of Mg alloy substrate, and tends to transform into hydroxyapatite (HA). Compared with uncoated Mg alloy, L929 cells exhibit good adherence, growth and proliferation characteristics on the coated Mg alloy, indicating that the cytocompatibility is significantly improved with the calcium phosphate coating.
基金Project (31100693/C100302) supported by the National Natural Science Foundation of ChinaProject (31011120049) supported by the Australia-China Special Fund, International Science Linkages Program co-supported by the Department of Innovation, Industry, Science and Research of Australia, and the Ministry of Science and Technology and National Science Foundation of China+1 种基金Project(2010ZDKG-96) supported by the Major Subject of "13115" Programs of Shaan’xi Province, ChinaProject (2012CB619102) supported by the National Basic Research Program of China
文摘The haemocompatibility of Ti-3Zr-2Sn-3Mo-25Nb biomedical alloy was studied after surface heparinization. A layer of sol-gel TiO2 films was applied on the alloy samples followed by active treatment in the bio-functionalized solution for introducing the OH- and groups, and then the heparin was immobilized on the active TiO2 films through the electrostatic self assembly technology. It is shown that the heparinized films are mainly composed of anatase and rutile with smooth and dense surface. In vitro blood compatibility was evaluated by haemolysis test, clotting time and platelet adhesion behavior tests. The results show that the haemocompatibility of the alloy could be significantly improved by surface heparinization.
基金Project(21071153)supported by the National Natural Science Foundation of China
文摘Li-rich layered transitional metal oxide Li1.2(Mn0.54Ni0.16Co0.08)O2 was prepared by sol-gel method and further modified by AlF3 coating via a wet process. The bare and AlF3-coated Li1.2(Mn0.54Ni0.16Co0.08)O2 samples were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), and high resolution transmission electron microscope(HRTEM). XRD results show that the bare and AlF3-coated samples have typical hexagonal α-Na Fe O2 structure, and AlF3-coated layer does not affect the crystal structure of the bare Li1.2(Mn0.54Ni0.16Co0.08)O2. Morphology measurements present that the AlF3 layer with a thickness of 5-7 nm is coated on the surface of the Li1.2(Mn0.54Ni0.16Co0.08)O2 particles.Galvanostatic charge-discharge tests at various rates show that the AlF3-coated Li1.2(Mn0.54Ni0.16Co0.08)O2 has an enhanced electrochemical performance compared with the bare sample. At 1C rate, it delivers an initial discharge capacity of 208.2 m A·h/g and a capacity retention of 72.4% after 50 cycles, while those of the bare Li1.2(Mn0.54Ni0.16Co0.08)O2 are 191.7 m A·h/g and 51.6 %, respectively.
基金Supported by the National Natural Science Foundation of China (No.60175020) the National High Tech Development '863' Program of China (No.2002AA117010-09).
文摘This letter adopts a GA (Genetic Algorithm) approach to assist in learning scaling of features that are most favorable to SVM (Support Vector Machines) classifier, which is named as GA-SVM. The relevant coefficients of various features to the classification task, measured by real-valued scaling, are estimated efficiently by using GA. And GA exploits heavy-bias operator to promote sparsity in the scaling of features. There are many potential benefits of this method:Feature selection is performed by eliminating irrelevant features whose scaling is zero, an SVM classifier that has enhanced generalization ability can be learned simultaneously. Experimental comparisons using original SVM and GA-SVM demonstrate both economical feature selection and excellent classification accuracy on junk e-mail recognition problem and Internet ad recognition problem. The experimental results show that comparing with original SVM classifier, the number of support vector decreases significantly and better classification results are achieved based on GA-SVM. It also demonstrates that GA can provide a simple, general, and powerful framework for tuning parameters in optimal problem, which directly improves the recognition performance and recognition rate of SVM.
文摘The letter presents an improved two-dimensional linear discriminant analysis method for feature extraction. Compared with the current two-dimensional methods for feature extraction, the improved two-dimensional linear discriminant analysis method makes full use of not only the row and the column direc-tion information of face images but also the discriminant information among different classes. The method is evaluated using the Nanjing University of Science and Technology (NUST) 603 face database and the Aleix Martinez and Robert Benavente (AR) face database. Experimental results show that the method in the letter is feasible and effective.
文摘This letter proposes an effective method for recognizing face images by combining two-Dimen- sional Principal Component Analysis (2DPCA) with IMage Euclidean Distance (IMED) method. The proposed method is comprised of four main stages. The first stage uses the wavelet decomposition to extract low fre- quency subimages from original face images and omits the other three subimages. The second stage concerns the application of IMED to face images. In the third stage, 2DPCA is employed to extract the face features from the processed results in the second stage. Finally, Support Vector Machine (SVM) is applied to classify the extracted face features. Experimental results on the AR face image database show that the proposed method yields better recognition performance in comparison with the 2DPCA method that is not combined with IMED.
文摘Four methods, including voltammetric measurement of double layer capacitance, surface oxides reduction, under potential deposition of Cu and carbon monoxide (CO) stripping have been applied to evaluate the real surface area of a polycrystalline Pd (pc-Pd) electrode. The results reveal that the second and third methods lead to consistent results with deviations below 5%. And from the determined double layer capacitance and CO stripping charge, it is deduced that the double layer capacity unit area is 23.1±0.4μF/cm2 and the saturated CO adlayer should be ca. 0.66 ML in order to ensure that the real surface area as determined is consistent with the other two techniques. The applicability as well as the attentions when applying these techniques for the determination of the real surface area of pc-Pd electrodes have been discussed.
基金Supported by the New Century Excellent Talents in University(NCET-10-0623)National Natural Science Foundation for Distinguished Young Scholars(21125627)+1 种基金National Basic Research Program of China(2009CB623404)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(Dong Hua University)
文摘The interfacial compatibility of composite membrane is an important factor to its structural stability, andseparation performance. In this study, poly (ether sulfone) (PES) support layer was first hydrophilically modified with poly(vinyl alcohol) (PVA) via surface segregation during the phase inversion process. Gelatin (GE) was then cast on the PVA-modified PES support layer as the active layer followed by crosslinking to fabricate composite membranes for ethanol dehydration. The enrichment of PVA on the surface of support layer improved interfacial compatibility of the as-prepared GE/PVA-PES composite membrane. The water contact angle measurement and X-ray photoelectron spectroscopy (XPS) data confirmed the surface segregation of PVA with a surface coverage density of -80%. T-peel test showed that the maxima/force to separate the support layer and the active layer was enhanced by 3 times compared with the GE/PES membrane. The effects of PVA content in the support layer, crosslinking of GE active layer and operating parameters on the pervaporative dehydration performance were investigated. The operational stability of the composite membrane was tested by immersing the membrane in ethanol aqueous solution for a period of time. Stable pervaporation performance for dehydration of 90% ethanol solution was obtained for GE/PVA-PES membrane with a separation factor of -60 and a permeation flux of -1910 g.m^-2.h1 without peeling over 28 days immersion.
基金supported by the National Natural Science Foundation of China(91338108,91438206)
文摘The harsh space radiation environment compromises the reliability of an on-board switching fabric by leading to cross-point and switching element(SE)faults.Different from traditional faulttolerant switching fabrics only taking crosspoint faults into account,a novel Input and Output Parallel Clos network,referred to as the(p_1,p_2)-IOPClos,is proposed to tolerate both cross-point and SE faults.In the(p_1,p_2)-IOPClos,there are p_1 and p_2 expanded parallel switching planes in the input and output stages,respectively.The multiple input/output switching planes are interconnected through the middle stage to provide multiple paths in each stage by which the network throughput can be increased remarkably.Furthermore,the network reliability of the(p_1,p_2)-IOPClos under the above both kinds of faults is analyzed.The corresponding implementation cost is also presented along with the network size.Both theoretical analysis and numerical results indicate that the(p_1,p_2)-IOPClos outperforms traditional Clos-type networks at reliability,while has less implementation cost than the multi-plane Clos network.
基金This work was funded by Natural Science Foundation of Fujian Province (No. 2008J0227) and Science and Technology Office of Fujian Province (No. 2007F5030),
文摘The bamboo powder/polycaprolactone composites (BPPC) were prepared by torque-rheometer to investigate the effects of recipes and processing conditions on the theological properties of BPPC. The morphological behavior and mechanical properties of BPPC were also studied. Results showed that the optimum recipe for composite materials is composed of 70% of polycaprolactone, 30% of bamboo powder according to volume, 1.6 % of aluminate coupling agent, 1.2% of stearic acid, and 2% of paraffin to bamboo powder according to mass ratio The optimum processing condition parameters were determined as the rotational speed at 50 r-min^-1 and the temperature at 100℃ for BPPC. The BPPC (containing 30 copies bamboo powder) possessed eminent interfacial compatibility and mechanical properties of BPPC.
文摘Sloshing phenomenon in a moving container is a complicated free surface flow problem. It has a wide range of engineering applications, especially in tanker ships and Liquefied Natural Gas (LNG) carriers. When the tank in these vehicles is partially filled, it is essential to be able to evaluate the fluid dynamic loads on tank perimeter. Different geometric shapes such as rectangular, cylindrical, elliptical, spherical and circular conical have been suggested for ship storage tanks by previous researchers. In this paper a numerical model is developed based on incompressible and inviscid fluid motion for the liquid sloshing phenomenon. The coupled BEM-FEM is used to solve the governing equations and nonlinear free surface boundary conditions. The results are validated for rectangular container using data obtained for a horizontal periodic sway motion. Using the results of this model a new arrangement of trapezoidal shapes with quadratic sidewalls is suggested for tanker ship storage panels. The suggested geometric shape not only has a maximum surrounded tank volume to the constant available volume, but also reduces the sloshing effects more efficiently than the existing geometric shapes.
文摘A nano-Li3V2(PO4)3/C powder was successfully prepared by a thermal polymerization method. The particle sizes of the intermediate product powder and the final product Li3V2(PO4)3 are all less than 200 nm. The carbon is partially coated on the surface of Li3V2(PO4)3 particles and the rest exists between particles with a total carbon content of 4.6wt%. This nano-Li3V2(PO4)3/C sample shows a discharge capacity of 124 mAh/g with-out capacity fading after 100 cycles at 0.1 C in the voltage rang of 3.0-4.3 V. Excellent rate performance is also achieved with a capacity of 80 mAh/g at 20 C in 3.0-4.3 V and 100 mAh/g at 10 C in 3.0-4.8 V. This study suggests that the thermal polymerization method is suitable to synthesize nano-Li3V2(PO4)3/C materials.
文摘According to the characteristics of the methane hydrate condensing and accumulating methane, authors put forward a new technique thought way to prevent the accident of coal and gas outburst by urging the methane in the coal seams to form hydrate. The paper analyzes the feasibility of forming the methane hydrate in the coal seam from the several sides, such as, temperature,pressure, and gas components, and the primary trial results indicate the problems should be settled before the industrialization appliance realized.
文摘In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator and universal frequency to digital converter (UFDC). Due to variation in angular displacement in the variable area type capacitor which is connected in the timer based astable circuit,capacitance changes which in turn changes the time period of the timer circuit output. The time period of the timer output waveform is linear with the capacitance and hence linear with angular displacement. The timer output is further processed with UFDC for the measurement. The experimental results show that the time period is linear with the angular displacement in the range of 0- 180° and the uncertainty we should associate it with this average time period value is the standard deviation of the mean,often called the standard error (SE),which is ± 0.023 μs. Because of the simplicity,this measurement system can be used in both electronic and industrial instrumentation.
文摘In this paper we describe the decomposition problem of a special kind of Ap,n,4p-5 polyhedra by using the associated matrices and their admissible operations.