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Multiple transformation analysis for interference separation in TDCS
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作者 WANG Guisheng WANG Yequn +1 位作者 DONG Shufu HUANG Guoce 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第5期1064-1078,共15页
Various types of interference signals limit the practical application of transform domain communication systems(TDCSs)in the severe electromagnetic field,an orthogonal basis learning method of transformation analysis(... Various types of interference signals limit the practical application of transform domain communication systems(TDCSs)in the severe electromagnetic field,an orthogonal basis learning method of transformation analysis(OBL-TA)is proposed to effectively address the problem of obtaining an optimal transform domain based on sparse representation.Then,the sparse availability is utilized to obtain the optimal transformation analysis by the iterative methods,which yields the sparse representation for transform domain(SRTD)in unrestricted form.In addition,the iterative version of SRTD(I-SRTD)in unrestricted form is obtained by decomposing the SRTD problem into three sub-problems and each sub-problem is iteratively solved by learning the best orthogonal basis.Furthermore,orthogonal basis learning via cost function minimization process is conducted by stochastic descent,which is assured to converge to a local minimum at least.Finally,the optimal transformation analysis is developed by the effectiveness of different transform domains according to the accuracy of the sparse representation and an optimal transformation analysis separately(OPTAS)is applied to the synthesized signal forms with conic alternatives,dualization,and smoothing.Simulation results demonstrate that the superiorities of the proposed methods achieve the optimal recovery and separation more rapidly and accurately than conventional methods. 展开更多
关键词 transformation analysis interference separation sparse representation transform domain communication system(TDCS)
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An effective thermodynamic transformation analysis method for actual irreversible cycle 被引量:5
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作者 CHEN ZeShao XIE WenHai +2 位作者 HU Peng JIA Lei SHI Min 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第9期2188-2193,共6页
An effective thermodynamic transformation analysis method was proposed in this study. According to the phenomenon of ex- ergy consumption always coupling with heat transfer process, the effective thermodynamic tempera... An effective thermodynamic transformation analysis method was proposed in this study. According to the phenomenon of ex- ergy consumption always coupling with heat transfer process, the effective thermodynamic temperatures were defined, then the actual power cycle or refrigeration/heat pump cycle was transformed into the equivalent reversible Carnot or reverse Carnot cycles for thermodynamic analysis. The derived effective thermodynamic temperature of the hot reservoir of the equivalent reverse Camot cycle is the basis of the proposed method. The combined diagram of TR-h and TR-q was adopted for the analy- sis of the system performance and the exergy consumption, which takes advantage of the visual expression of the heat/work exchange and the enthalpy change, and is convenient for the calculation of the coefficient of performance and exergy con- sumptions. Take a heat pump water heater with refrigerant of R22 for example, the proposed method was systematically intro- duced, and the fitting formulas of the effective thermodynamic temperatures were given as demonstration. The results show that the proposed method has advantage and well application foreground in the performance simulation and estimation under the variable working conditions. 展开更多
关键词 irreversible thermodynamic cycle effective thermodynamic transformation analysis effective thermodynamic temper-ature heat pump water heater exergy analysis
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Simultaneous Determination of Rare Earth Elements by Dual-System Iterative Target Transformation Factor Analysis
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作者 Liu, Delong Yang, Yansheng 《Journal of Rare Earths》 SCIE EI CAS CSCD 1999年第2期68-71,共4页
Dualcolor systems were used to reduce the collinearity of multicomponent spectra, which is described by the angles between spectra vectors. Combined with iterative target transformation factor analysis, single rare ea... Dualcolor systems were used to reduce the collinearity of multicomponent spectra, which is described by the angles between spectra vectors. Combined with iterative target transformation factor analysis, single rare earth element was determined in its mixture. The calculated results show that the average angle between rare earth spectra in one color system(trichloroarsenazorare earths, pH 34) is 45, and that in two color systems(trichloroarsenazorare earths, pH 34, 14) is 215. This technique makes it easy to select the real number of the components in mixtures, and the determination results show dualcolor system method is an effective technique in rare earth mixture analysis. 展开更多
关键词 Rare earths Multicomponent analysis Iterative target transformation factor analysis
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A preliminary analysis of physical mechanism of transformation process from a landed typhoon into an extratropical cyclone
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作者 Zhang Qiuqing and Ding Yihui 1. National Research Center for Marine. Environment Forecasts, Beijing 100081, China2. Academy of Meteorological Science, State Meteorological Administration, Beijing 100081, China 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1992年第4期525-535,共11页
A diagnostic study is performed in the paper on the process of typhoon Norris (1980) transforming into an ex-tratropical cyclone after its landing over Southeast China. The main findings are as follows:The changes of ... A diagnostic study is performed in the paper on the process of typhoon Norris (1980) transforming into an ex-tratropical cyclone after its landing over Southeast China. The main findings are as follows:The changes of kinetic energy are mainly attributed to the generation due to non-divergent wind. During the early stage of the typhoon landing, there exits only a small quantity of kinetic energy exchanging with the environment. And after it is transformed into an extratropical cyclone, a large amount of kinetic energy is exported from the system toward the environment.The horizontal and vertical flux-divergence terms of eddy available potenlial energy are the prominent sinks in the budgets of eddy kinetic energy. The generations of eddy kinetic energy due to both the barotropic and baroclinic processes are source terms. The former is remarkable during the initial stage. But after the depression is transformed into an extratropical cyclone, the roles of the generation by the barotropic and baroclinic processes are reversed, 1. e. , the latter has become more significant than the former.Diabatic heating is the most dominant heat source. The terms of vertical heat flux by cumulus and large-scale motion are the major sinks. And the latter is prominent after the system is transformed into an extratropical cycfone. 展开更多
关键词 A preliminary analysis of physical mechanism of transformation process from a landed typhoon into an extratropical cyclone
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An Efficient Technique for One-Dimensional Fractional Diffusion EquationModel for Cancer Tumor
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作者 Daasara Keshavamurthy Archana Doddabhadrappla Gowda Prakasha +1 位作者 Pundikala Veeresha Kottakkaran Sooppy Nisar 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第11期1347-1363,共17页
This study intends to examine the analytical solutions to the resulting one-dimensional differential equation of acancer tumor model in the frame of time-fractional order with the Caputo-fractional operator employing ... This study intends to examine the analytical solutions to the resulting one-dimensional differential equation of acancer tumor model in the frame of time-fractional order with the Caputo-fractional operator employing a highlyefficient methodology called the q-homotopy analysis transform method.So,the preferred approach effectivelyfound the analytic series solution of the proposed model.The procured outcomes of the present frameworkdemonstrated that this method is authentic for obtaining solutions to a time-fractional-order cancer model.Theresults achieved graphically specify that the concerned paradigm is dependent on arbitrary order and parametersand also disclose the competence of the proposed algorithm. 展开更多
关键词 Caputo-fractional derivative Laplace transforms cancer tumor model q-homotopy analysis transform method
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Coconut Fiber Pyrolysis: Bio-Oil Characterization for Potential Application as an Alternative Energy Source and Production of Bio-Degradable Plastics
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作者 Patrick Ssemujju Lubowa Hiram Ndiritu +1 位作者 Peter Oketch James Mutua 《World Journal of Engineering and Technology》 2024年第2期310-319,共10页
The current energy crisis could be alleviated by enhancing energy generation using the abundant biomass waste resources. Agricultural and forest wastes are the leading organic waste streams that can be transformed int... The current energy crisis could be alleviated by enhancing energy generation using the abundant biomass waste resources. Agricultural and forest wastes are the leading organic waste streams that can be transformed into useful alternative energy resources. Pyrolysis is one of the technologies for converting biomass into more valuable products, such as bio-oil, bio-char, and syngas. This work investigated the production of bio-oil through batch pyrolysis technology. A fixed bed pyrolyzer was designed and fabricated for bio-oil production. The major components of the system include a fixed bed reactor, a condenser, and a bio-oil collector. The reactor was heated using a cylindrical biomass external heater. The pyrolysis process was carried out in a reactor at a pressure of 1atm and a varying operating temperature of 150˚C, 250˚C, 350˚C to 450˚C for 120 minutes. The mass of 1kg of coconut fiber was used with particle sizes between 2.36 mm - 4.75 mm. The results show that the higher the temperature, the more volume of bio-oil produced, with the highest yield being 39.2%, at 450˚C with a heating rate of 10˚C/min. The Fourier transformation Infrared (FTIR) Spectroscopy analysis was used to analyze the bio-oil components. The obtained bio-oil has a pH of 2.4, a density of 1019.385 kg/m<sup>3</sup>, and a calorific value of 17.5 MJ/kg. The analysis also showed the presence of high-oxygenated compounds;carboxylic acids, phenols, alcohols, and branched oxygenated hydrocarbons as the main compounds present in the bio-oil. The results inferred that the liquid product could be bestowed as an alternative resource for polycarbonate material production. 展开更多
关键词 Batch Pyrolysis Technology Coconut Fiber BIO-OIL Fourier transformation Infrared analysis
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New homotopy analysis transform method for solving the discontinued problems arising in nanotechnology 被引量:4
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作者 M.M.Khader Sunil Kumar S.Abbasbandy 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第11期135-139,共5页
We present a new reliable analytical study for solving the discontinued problems arising in nanotechnology. Such problems are presented as nonlinear differential-difference equations. The proposed method is based on t... We present a new reliable analytical study for solving the discontinued problems arising in nanotechnology. Such problems are presented as nonlinear differential-difference equations. The proposed method is based on the Laplace trans- form with the homotopy analysis method (HAM). This method is a powerful tool for solving a large amount of problems. This technique provides a series of functions which may converge to the exact solution of the problem. A good agreement between the obtained solution and some well-known results is obtained. 展开更多
关键词 discretized mKdV lattice equation nonlinear differential-difference equations Laplace transform homotopy analysis transform method
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RESEARCH OF WAVELET TRANSFORM INSTRUMENT SYSTEM FOR SIGNAL ANALYSIS 被引量:11
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作者 Qin Shuren Chen Zhikui +3 位作者 Tang Baoping Yang Changqi Xu Mingtao He Hui (Test Center, Chongqing University) 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2000年第2期114-121,共8页
After brief describing the Principle of wavelet transform (WT) of signals, a new signals analysis system based on wavelet transform is introduced. The design and development of the instryment of wavelet transform are ... After brief describing the Principle of wavelet transform (WT) of signals, a new signals analysis system based on wavelet transform is introduced. The design and development of the instryment of wavelet transform are described. A number of practical uses of this system demonstrate that wavelet transform system is specially functional in identifying and processing impulse, singular and non-smooth signals, so that it should be evaluated the most advanced signal analyzing system. 展开更多
关键词 Wavelet transform Signal analysis Instrument
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Comprehensive Reliability Allocation Method for CNC Lathes Based on Cubic Transformed Functions of Failure Mode and Effects Analysis 被引量:8
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作者 YANG Zhou ZHU Yunpeng +1 位作者 REN Hongrui ZHANG Yimin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第2期315-324,共10页
Reliability allocation of computerized numerical controlled(CNC)lathes is very important in industry.Traditional allocation methods only focus on high-failure rate components rather than moderate failure rate compon... Reliability allocation of computerized numerical controlled(CNC)lathes is very important in industry.Traditional allocation methods only focus on high-failure rate components rather than moderate failure rate components,which is not applicable in some conditions.Aiming at solving the problem of CNC lathes reliability allocating,a comprehensive reliability allocation method based on cubic transformed functions of failure modes and effects analysis(FMEA)is presented.Firstly,conventional reliability allocation methods are introduced.Then the limitations of direct combination of comprehensive allocation method with the exponential transformed FMEA method are investigated.Subsequently,a cubic transformed function is established in order to overcome these limitations.Properties of the new transformed functions are discussed by considering the failure severity and the failure occurrence.Designers can choose appropriate transform amplitudes according to their requirements.Finally,a CNC lathe and a spindle system are used as an example to verify the new allocation method.Seven criteria are considered to compare the results of the new method with traditional methods.The allocation results indicate that the new method is more flexible than traditional methods.By employing the new cubic transformed function,the method covers a wider range of problems in CNC reliability allocation without losing the advantages of traditional methods. 展开更多
关键词 CNC lathes reliability failure modes and effects analysis(FMEA) cubic transformed function comprehensive allocation
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Characteristic wavelength selection of volatile organic compounds infrared spectra based on improved interval partial least squares 被引量:2
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作者 Wei Ju Changhua Lu +4 位作者 Yujun Zhang Weiwei Jiang Jizhou Wang Yi Bing Lu Feng Hong 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2019年第2期35-53,共19页
As important components of air pollutant,volatile organic compounds(VOCs)can cause great harm to environment and human body.The concentration change of VOCs should be focused on in real-time environment monitoring sys... As important components of air pollutant,volatile organic compounds(VOCs)can cause great harm to environment and human body.The concentration change of VOCs should be focused on in real-time environment monitoring system.In order to solve the problem of wavelength redundancy in full spectrum partial least squares(PLS)modeling for VOCs concentration analysis,a new method based on improved interval PLS(iPLS)integrated with Monte-Carlo sampling,called iPLS-MC method,was proposed to select optimal characteristic wavelengths of VOCs spectra.This method uses iPLS modeling to preselect the characteristic wavebands of the spectra and generates random wavelength combinations from the selected wavebands by Monte-Carlo sampling.The wavelength combination with the best prediction result in regression model is selected as the characteristic wavelengths of the spectrum.Different wavelength selection methods were built,respectively,on Fourier transform infrared(FTIR)spectra of ethylene and ethanol gas at different concentrations obtained in the laboratory.When the interval number of iPLS model is set to 30 and the Monte-Carlo sampling runs 1000 times,the characteristic wavelengths selected by iPLS-MC method can reduce from 8916 to 10,which occupies only 0.22%of the full spectrum wavelengths.While the RMSECV and correlation coefficient(Rc)for ethylene are 0.2977 and 0.9999 ppm,and those for ethanol gas are 0.2977 ppm and 0.9999.The experimental results show that the iPLS-MC method can select the optimal characteristic wavelengths of VOCs FTIR spectra stably and effectively,and the prediction performance of the regression model can be significantly improved and simplified by using characteristic wavelengths. 展开更多
关键词 Ambient air monitoring Fourier transform infrared spectra analysis variable selection interval partial least square Monte-Carlo sampling
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Identification method of seismic phase in three-component seismograms on the basis of wavelet transform 被引量:4
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作者 刘希强 周惠兰 +3 位作者 沈萍 杨选辉 马延路 李红 《Acta Seismologica Sinica(English Edition)》 CSCD 2000年第2期136-142,共7页
This paper puts forward wavelet transform method to identify P and S phases in three component seismograms using polarization information contained in the wavelet transform coefficients of signal. The P and S wave loc... This paper puts forward wavelet transform method to identify P and S phases in three component seismograms using polarization information contained in the wavelet transform coefficients of signal. The P and S wave locator functions are constructed by using eigenvalue analysis method to wavelet transform coefficient across several scales. Locator functions formed by wavelet transform have stated noise resistance capability, and is proved to be very effective in identifying the P and S arrivals of the test data and actual earthquake data. 展开更多
关键词 wavelet transform eigenvalue analysis seismic phase identification
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Effects of slip condition on MHD stagnation-point flow over a power-law stretching sheet 被引量:1
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作者 朱婧 郑连存 张志刚 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2010年第4期439-448,共10页
The steady two-dimensional magnetohydrodynamic stagnation flow towards a nonlinear stretching surface is studied. The no-slip condition on the solid boundary is replaced with a partial slip condition. A scaling group ... The steady two-dimensional magnetohydrodynamic stagnation flow towards a nonlinear stretching surface is studied. The no-slip condition on the solid boundary is replaced with a partial slip condition. A scaling group transformation is used to get the invariants. Using the invariants, a third-order ordinary differential equation corresponding to the momentum is obtained. An analytical solution is obtained in a series form using a homotopy analysis method. Reliability and efficiency of series solutions are shown by the good agreement with numerical results presented in the literature. The effects of the slip parameter, the magnetic field parameter, the velocity ratio parameter, the suction velocity parameter, and the power law exponent on the flow are investigated. The results show that the velocity and shear stress profiles are greatly influenced by these parameters. 展开更多
关键词 boundary layer slip flow stagnation point scaling group transformation homotopy analysis method
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Fingerprint Liveness Detection Based on Multi-Scale LPQ and PCA 被引量:13
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作者 Chengsheng Yuan Xingming Sun Rui Lv 《China Communications》 SCIE CSCD 2016年第7期60-65,共6页
Fingerprint authentication system is used to verify users' identification according to the characteristics of their fingerprints.However,this system has some security and privacy problems.For example,some artifici... Fingerprint authentication system is used to verify users' identification according to the characteristics of their fingerprints.However,this system has some security and privacy problems.For example,some artificial fingerprints can trick the fingerprint authentication system and access information using real users' identification.Therefore,a fingerprint liveness detection algorithm needs to be designed to prevent illegal users from accessing privacy information.In this paper,a new software-based liveness detection approach using multi-scale local phase quantity(LPQ) and principal component analysis(PCA) is proposed.The feature vectors of a fingerprint are constructed through multi-scale LPQ.PCA technology is also introduced to reduce the dimensionality of the feature vectors and gain more effective features.Finally,a training model is gained using support vector machine classifier,and the liveness of a fingerprint is detected on the basis of the training model.Experimental results demonstrate that our proposed method can detect the liveness of users' fingerprints and achieve high recognition accuracy.This study also confirms that multi-resolution analysis is a useful method for texture feature extraction during fingerprint liveness detection. 展开更多
关键词 fingerprint liveness detection wavelet transform local phase quantity principal component analysis support vector machine
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Efficient Supply Current Control Strategies for Bridgeless Interleaved AC-DC Converter
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作者 R.Sasikala R.Seyezhai 《Computer Systems Science & Engineering》 SCIE EI 2022年第10期175-191,共17页
This paper presents an efficient supply current wave shaping technique for bridgeless interleaved Single Ended Primary Inductor Converter(SEPIC).The SEPIC converter converts an Alternating Current(AC)to Direct Current... This paper presents an efficient supply current wave shaping technique for bridgeless interleaved Single Ended Primary Inductor Converter(SEPIC).The SEPIC converter converts an Alternating Current(AC)to Direct Current(DC)with the boost converter.Power Factor Correction(PFC)is progressively significant to achieve high energy efficiency.The overall system efficiency can be increased as the bridgeless topology has less conduction losses from rectifying bridges.Also,the bridgeless and interleaved techniques are incorporated in this study to achieve better performance.The performance of the system is analyzed on both current control and sensor-less techniques.Different controllers such as Proportional Integral(PI)control,peak current control,Non-Linear Carrier(NLC)control,and sensor-less current control are integrated.All the above controllers are implemented using MATrix LABoratory(MATLAB)/SIMULINK.The performance parameter,namely Power Factor(PF),Total Harmonic Distortion(THD),is computed for both open loop and closed loop condition.The sensor-less current control method is implemented using the DsPIC30F2010 controller.The circuit performance is also verified from the simulation and hardware results.The proposed controller has inbuilt Analog-to-Digital Converter(ADC),Digital-to-Analog Converter(DAC),Pulse Width Modulation(PWM)generator,and provides fast responses. 展开更多
关键词 Light emitting diode power factor correction SEPIC converter current control method sensor-less method fast Fourier transform analysis for input current
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Regarding on the Fractional Mathematical Model of Tumour Invasion and Metastasis
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作者 P.Veeresha Esin Ilhan +2 位作者 D.G.Prakasha Haci Mehmet Baskonus Wei Gao 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第6期1013-1036,共24页
In this paper,we analyze the behaviour of solution for the system exemplifying model of tumour invasion and metastasis by the help of q-homotopy analysis transform method(q-HATM)with the fractional operator.The analyz... In this paper,we analyze the behaviour of solution for the system exemplifying model of tumour invasion and metastasis by the help of q-homotopy analysis transform method(q-HATM)with the fractional operator.The analyzed model consists of a system of three nonlinear differential equations elucidating the activation and the migratory response of the degradation of the matrix,tumour cells and production of degradative enzymes by the tumour cells.The considered method is graceful amalgamations of q-homotopy analysis technique with Laplace transform(LT),and Caputo–Fabrizio(CF)fractional operator is hired in the present study.By using the fixed point theory,existence and uniqueness are demonstrated.To validate and present the effectiveness of the considered algorithm,we analyzed the considered system in terms of fractional order with time and space.The error analysis of the considered scheme is illustrated.The variations with small change time with respect to achieved results are effectively captured in plots.The obtained results confirm that the considered method is very efficient and highly methodical to analyze the behaviors of the system of fractional order differential equations. 展开更多
关键词 Tumour cell invasion and metastasis q-homotopy analysis transform method Caputo–Fabrizio derivative
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Post-annealing effect on the structural and mechanical properties of multiphase zirconia films deposited by a plasma focus device
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作者 I.A.Khan R.S.Rawat +1 位作者 R.Ahmad M.A.K.Shahid 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第12期442-450,共9页
Nanostructured multiphase zirconia films (MZFs) are deposited on Zr substrate by the irradiation of energetic oxygen ions emanated from a plasma focus device. The oxygen operating gas pressure of 1 mbar (1 bar=105... Nanostructured multiphase zirconia films (MZFs) are deposited on Zr substrate by the irradiation of energetic oxygen ions emanated from a plasma focus device. The oxygen operating gas pressure of 1 mbar (1 bar=105 Pa) provides the most appropriate ion energy flux to deposit crystalline ZrO2 films. X-ray diffraction (XRD) patterns reveal the formation of polycrystalline ZrO2 films. The crystallite size (CS), crystal growth, and dislocation densities are attributed to increasing focus shots, sample axial distances, and working gas pressures. Phase and orientation transformations from t-ZrO2 to m-ZrO2 and c-ZrO2 are associated with increasing focus shots and continuous annealing. For lower (200 ℃) annealing temperature (AT), full width at half maximum (FWHM) of diffraction peak, CS, and dislocation density (δ) for (020) plane are found to be 0.494, 16.6 nm, and 3.63×10-3 nm-2 while for higher (400 ℃) AT, these parameters for (111) plane are found to be 0.388, 20.87 nm, and 2.29×10-3 nm-2, respectively. Scanning electron microscope (SEM) results demonstrate the formation of rounded grains with uniform distribution. The estimated values of atomic ratio (O/Zr) in ZrO2 films deposited for different axial distances (6 cm, 9 cm, and 12 cm) are found to be 2.1, 2.2, and 2.3, respectively. Fourier transform infrared (FTIR) analysis reveals that the bands appearing at 441 cm-1 and 480 cm-1 belong to m-ZrO2 and t-ZrO2 phases, respectively. Maximum microhardness (8.65±0.45 GPa) of ZrO2 film is ~ 6.7 times higher than the microhardness of virgin Zr. 展开更多
关键词 zrconia phase transformation XRD SEM Fourier transform infrared analysis
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Dengue Climate Variability in Rio de Janeiro City with Cross-Wavelet Transform
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作者 Suellen Araujo Franco dos Santos Hugo Abi Karam +9 位作者 Augusto José Pereira Filho lio Cesar Barreto da Silva Jose Luis Flores Rojas Julio Migue Angeles Suazo Isela Leonor Vá squez Panduro Cesar Arturo Sanchez Peñ a 《Journal of Environmental Protection》 2022年第3期261-276,共16页
Dengue is one of the most prominent tropical epidemic diseases present in the Rio de Janeiro city and Southeast part of Brazil, due to the widespread conditions of occurrence of the dengue vector, the mosquito Aedesae... Dengue is one of the most prominent tropical epidemic diseases present in the Rio de Janeiro city and Southeast part of Brazil, due to the widespread conditions of occurrence of the dengue vector, the mosquito Aedesaegypti, such as high-temperature days interlaced with afternoon or nocturnal rainstorms in summer. This work has the objective of investigating the relationships between variabilities of the El Ni?o-South Oscillation (ENSO) and greater epidemics of dengue in Rio de Janeiro city. To accomplish this goal, the analysis and signal decomposition by cross-wavelet transform (WT) was applied to obtain the cross variability associated with variations of power and phase of both signals by characteristic periods and along with the time series. Data considered in the analysis are (the decimal logarithm of normalized value) of the monthly available notifications of dengue worsening, provided by the public health system of Brazil, and the Southern Oscillation Index (SOI) Ni?o 3.4 data, provided by the National Oceanic and Atmospheric Administration (NOAA), in the period 2000-2017. A maximum cross-wavelet power close to 0.45 was obtained for the representative period of 1 year and also to periods between 3 and 4 years, associated with the positive phase of the SOI index (i.e. , La Ni?a) or with a transition to the positive phase. The evolution of the combined variability of SOI and dengue can be expressed by progressive differences in phase along the time, eventually resulting in yielding phases (i.e., La Niña-Dengue epidemic). 展开更多
关键词 Dengue Fever Cross-Wavelet Transform analysis El Niño-Southern Oscillation Index
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A Note on the Solution of Water Wave Scattering Problem Involving Small Deformation on a Porous Channel-Bed
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作者 S.Mohapatra M.R.Sarangi 《Journal of Marine Science and Application》 CSCD 2017年第1期10-19,共10页
The solution of water wave scattering problem involving small deformation on a porous bed in a channel, where the upper surface is bounded above by an infinitely extent rigid horizontal surface, is studied here within... The solution of water wave scattering problem involving small deformation on a porous bed in a channel, where the upper surface is bounded above by an infinitely extent rigid horizontal surface, is studied here within the framework of linearized water wave theory. In such a situation, there exists only one mode of waves propagating on the porous surface. A simplified perturbation analysis, involving a small parameter ε (≤1) , which measures the smallness of the deformation, is employed to reduce the governing Boundary Value Problem (BVP) to a simpler BVP for the first-order correction of the potential function. The first-order potential function and, hence, the first-order reflection and transmission coefficients are obtained by the method based on Fourier transform technique as well as Green's integral theorem with the introduction of appropriate Green's function. Two special examples of bottom deformation: the exponentially damped deformation and the sinusoidal ripple bed, are considered to validate the results. For the particular example of a patch of sinusoidal ripples, the resonant interaction between the bed and the upper surface of the fluid is attained in the neighborhood of a singularity, when the ripples wavenumbers of the bottom deformation become approximately twice the components of the incident field wavenumber along the positive x -direction. Also, the main advantage of the present study is that the results for the values of reflection and transmission coefficients are found to satisfy the energy-balance relation almost accurately. 展开更多
关键词 Porous bed bottom deformation perturbation analysis Fourier Transform Green's function reflection coefficient transmission coefficient energy identity water wave scattering
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Reliability analysis based on a novel density estimation method for structures with correlations 被引量:2
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作者 Baoyu LI Leigang ZHANG +2 位作者 Xuejun ZHU Xiongqing YU Xiaodong MA 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2017年第3期1021-1030,共10页
Estimating the Probability Density Function(PDF) of the performance function is a direct way for structural reliability analysis,and the failure probability can be easily obtained by integration in the failure domai... Estimating the Probability Density Function(PDF) of the performance function is a direct way for structural reliability analysis,and the failure probability can be easily obtained by integration in the failure domain.However,efficiently estimating the PDF is still an urgent problem to be solved.The existing fractional moment based maximum entropy has provided a very advanced method for the PDF estimation,whereas the main shortcoming is that it limits the application of the reliability analysis method only to structures with independent inputs.While in fact,structures with correlated inputs always exist in engineering,thus this paper improves the maximum entropy method,and applies the Unscented Transformation(UT) technique to compute the fractional moments of the performance function for structures with correlations,which is a very efficient moment estimation method for models with any inputs.The proposed method can precisely estimate the probability distributions of performance functions for structures with correlations.Besides,the number of function evaluations of the proposed method in reliability analysis,which is determined by UT,is really small.Several examples are employed to illustrate the accuracy and advantages of the proposed method. 展开更多
关键词 Fractional moment Maximum entropy Probability density function Reliability analysis Unscented transformation
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Thermogravimetric coupled with Fourier transform infrared analysis study on thermal treatment of monopotassium phosphate residue
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作者 Yuheng FENG Xuguang JIANG +2 位作者 Yong CHI Xiaodong LI Hongmei ZHU 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2011年第2期186-192,共7页
In China,safe disposal of hazardous waste is more and more a necessity,urged by rapid economic development.The pyrolysis and combustion characteristics of a residue from producing monopotassium phosphate(monopotassium... In China,safe disposal of hazardous waste is more and more a necessity,urged by rapid economic development.The pyrolysis and combustion characteristics of a residue from producing monopotassium phosphate(monopotassium phosphate residue),considered as a hazardous waste,were studied using a thermogravimetric,coupled with Fourier transform infrared analyzer(TGFTIR).Both pyrolysis and combustion runs can be subdivided into three stages:drying,thermal decomposition,and final devolatilization.The average weight loss rate during fast thermal decomposition stage in pyrolysis is higher than combustion.Acetic acid,methane,pentane,(acetyl)cyclopropane,2,4,6-trichlorophenol,CO,and CO_(2) were distinguished in the pyrolysis process,while CO_(2) was the dominant combustion product. 展开更多
关键词 hazardous waste COMBUSTION PYROLYSIS thermogravimetric coupled with Fourier transform infrared analysis(TG-FTIR) monopotassium phosphate residue
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