Simultaneous localization and mapping(SLAM) technology is a research hotspot in the field of intelligent mobile robot, and many researchers have developed many classic systems in the past few decades. However, most of...Simultaneous localization and mapping(SLAM) technology is a research hotspot in the field of intelligent mobile robot, and many researchers have developed many classic systems in the past few decades. However, most of the existing SLAM methods assume that the environment of the robot is static, which results in the performance of the system being greatly reduced in the dynamic environment. To solve this problem, a new dynamic object detection method based on point cloud motion analysis is proposed and incorporated into ORB-SLAM2. First, the method is regarded as a preprocessing stage, detecting moving objects in the scene, and then removing the moving objects to enhance the performance of the SLAM system. Experiments performed on a public RGB-D dataset show that the motion cancellation method proposed in this paper can effectively improve the performance of ORB-SLAM2 in a highly dynamic environment.展开更多
In order to study cavitation characteristics of a 2-D hydrofoil, the method that combines nonlinear cavitation model and mixed-iteration is used to predict and analyze the cavitation performance of hydrofoils. The cav...In order to study cavitation characteristics of a 2-D hydrofoil, the method that combines nonlinear cavitation model and mixed-iteration is used to predict and analyze the cavitation performance of hydrofoils. The cavitation elements are nonlinearly disposed based on the Green formula and perturbation potential panel method. At the same time, the method that combines cavity shape for fixed cavity length （CSCL） iteration and cavity shape for fixed cavitation number （CSCN） iteration is used to work out the thickness and length of hydrofoil cavitations. Through analysis of calculation results, it can be concluded that the jump of pressure and velocity potentially exist between cavitation end area and non-cavitations area on suction surface when cavitation occurs on hydrofoil. In certain angles of attack, the cavitation number has a negative impact on the length of cavitations. And under the same angle of attack and cavitation number, the bigger the thickness of the hydrofoil, the shorter the cavitations length.展开更多
A novel slow-down set waveform is proposed to improve the set performance and a 1 kb phase change random access memory chip fabricated with a 13nm CMOS technology is implemented to investigate the set performance by d...A novel slow-down set waveform is proposed to improve the set performance and a 1 kb phase change random access memory chip fabricated with a 13nm CMOS technology is implemented to investigate the set performance by different set programming strategies based on this new set pulse. The amplitude difference （I1 - I2） of the set pulse is proved to be a crucial parameter for set programming. We observe and analyze the cell characteristics with different I1 - I2 by means of thermal simulations and high-resolution transmission electron microscopy, which reveal that an incomplete set programming will occur when the proposed slow-down pulse is set with an improperly high I1 - I2. This will lead to an amorphous residue in the active region. We also discuss the programming method to avoid the set performance degradations.展开更多
Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food produ...Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food production, Sudan Dyes are banned to be used as food dyes in our country.展开更多
A technology called solar energy is a very promising technique, and is considered as the cleanest and the most abundant renewable resource that is naturally available every day. In this paper, a MATLAB environment has...A technology called solar energy is a very promising technique, and is considered as the cleanest and the most abundant renewable resource that is naturally available every day. In this paper, a MATLAB environment has been developed to calculate real-time power incidence on a PV system. It takes into account the time, location, PV tilt, and azimuth angles, and weather conditions to estimate incident power. In this paper, one case study is considered at New York State location. It has been applied to a newly installed 8 kW residential system located in Inwood. The solar panels are made up of silicon HIT (Heterojunction with Intrinsic Thin Layer) cells by Panasonic and solar cell rated at 19%. The result shows that the system is performing at its rated efficiency. The calculations involve the determination of direct, diffused and reflected radiation on the panels taking into account the time of the day, location, PV area, and orientations and weather conditions. The cloudiness index may be estimated based on the weather data and included in the calculations. After performing the irradiance calculations, the output power is estimated based on the rated efficiency at its temperature and compared with the generated output power. The real-time assessment of a PV system performance, during the operational time monitors the health of the PV system. The data obtained by this calculator may accompany production data provided to the consumer by the utility company.展开更多
This paper puts forward the connotation of enterprise green management and green management performance evaluation,analyzes the characteristics of enterprise green management performance evaluation and decomposes its ...This paper puts forward the connotation of enterprise green management and green management performance evaluation,analyzes the characteristics of enterprise green management performance evaluation and decomposes its content.Using the triple performance method,the paper constructs the performance evaluation index system of enterprise green management.Taking BH Petrochemical Co.,Ltd.at the high-efficiency ecological economic zone of the Yellow River Delta as an example,by using analytic hierarchy process(AHP)and Matlab programming,this paper determines the weight of each index in the enterprise green management performance evaluation index system,the fuzzy comprehensive evaluation method is used to evaluate the green management performance evaluation of industrial enterprises.The results show that the performance evaluation index system of enterprise green management constructed by"triple performance method"has important theoretical significance and application value for evaluating and guiding enterprises to strengthen their green management.展开更多
Plasma synthetic jet actuator（PSJA） has a wide application prospect in the high-speed flow control field for its high jet velocity.In this paper,the influence of the air pressure on the performance of a two-electrod...Plasma synthetic jet actuator（PSJA） has a wide application prospect in the high-speed flow control field for its high jet velocity.In this paper,the influence of the air pressure on the performance of a two-electrode PSJA is investigated by the schlieren method in a large range from 7 k Pa to 100 k Pa.The energy consumed by the PSJA is roughly the same for all the pressure levels.Traces of the precursor shock wave velocity and the jet front velocity vary a lot for different pressures.The precursor shock wave velocity first decreases gradually and then remains at 345 m/s as the air pressure increases.The peak jet front velocity always appears at the first appearance of a jet,and it decreases gradually with the increase of the air pressure.A maximum precursor shock wave velocity of 520 m/s and a maximum jet front velocity of 440 m/s are observed at the pressure of 7 k Pa.The averaged jet velocity in one period ranges from 44 m/s to 54 m/s for all air pressures,and it drops with the rising of the air pressure.High velocities of the precursor shock wave and the jet front indicate that this type of PSJA can still be used to influence the high-speed flow field at 7 k Pa.展开更多
The prediction process often runs with small samples and under-sufficient information.To target this problem,we propose a performance comparison study that combines prediction and optimization algorithms based on expe...The prediction process often runs with small samples and under-sufficient information.To target this problem,we propose a performance comparison study that combines prediction and optimization algorithms based on experimental data analysis.Through a large number of prediction and optimization experiments,the accuracy and stability of the prediction method and the correction ability of the optimization method are studied.First,five traditional single-item prediction methods are used to process small samples with under-sufficient information,and the standard deviation method is used to assign weights on the five methods for combined forecasting.The accuracy of the prediction results is ranked.The mean and variance of the rankings reflect the accuracy and stability of the prediction method.Second,the error elimination prediction optimization method is proposed.To make,the prediction results are corrected by error elimination optimization method(EEOM),Markov optimization and two-layer optimization separately to obtain more accurate prediction results.The degree improvement and decline are used to reflect the correction ability of the optimization method.The results show that the accuracy and stability of combined prediction are the best in the prediction methods,and the correction ability of error elimination optimization is the best in the optimization methods.The combination of the two methods can well solve the problem of prediction with small samples and under-sufficient information.Finally,the accuracy of the combination of the combined prediction and the error elimination optimization is verified by predicting the number of unsafe events in civil aviation in a certain year.展开更多
An analytical method was developed and validated for determination of patulin in apple puree by HPLC. Extraction and clean-up ofpatulin from clear extract are achieved on AFFINIMIP SPEPATULIN cartridges. Patulin is th...An analytical method was developed and validated for determination of patulin in apple puree by HPLC. Extraction and clean-up ofpatulin from clear extract are achieved on AFFINIMIP SPEPATULIN cartridges. Patulin is then separated on a Hypersil GOLD column 150 mm × 4 mm, 5 μtmand detected at 276 nm. The recovery in the range of 5 μg/kg-80 μg/kg was 81.47%. The limit of detection （LOD） was 1.36 μg/kg, and the limit of quantification （LOQ） was 4.55 μg/kg. The patulin content of the commercial samples of apple puree and samples of apple and fruit puree forinfants and young children as well as the samples of apple puree prepared from two apple varieties intended for processing （Jonathan, Florina） and obtained from conventional and uncertified organic cultures has been evaluated in this paper. The 44.83% patulin concentration of the analyzed samples were under the maximum level of the European Commission Regulation （EC） 1881/2006, in 46.55% of the analyzed samples patulin was not detected and in 8.62% of samples patulin concentration was lower than LOQ （European Comission, 2006a） Patulin was not detected in samples of apple puree intended for infants and young children consumption.展开更多
To address the insufficient integration of performance evaluation and contextual analysis in traditional architectural design,this paper proposes a design workflow that combines data-driven and performance-driven appr...To address the insufficient integration of performance evaluation and contextual analysis in traditional architectural design,this paper proposes a design workflow that combines data-driven and performance-driven approaches,establishing a comprehensive operational pathway from typology selection and design generation to performance assessment.Using Yanshen Ancient Town,a cold region,as the study area,the research evaluates 18 traditional courtyard types and 8 brick kiln courtyard types.Benchmark models are selected based on the combined performance of PET(Physiological Equivalent Temperature)and MRT(Mean Radiant Temperature)indices.Subsequently,multiple performance indicators,including indoor and outdoor thermal comfort,indoor illuminance,and building energy consumption,are integrated into the analysis.Using a genetic algorithm,Pareto optimal solutions that meet performance requirements are iteratively optimized and filtered.Based on the learning rates and various evaluation indicators,XGBoost is ultimately selected to classify and predict the overall building performance.Results indicate that the model achieves an average prediction accuracy of 83.6%.Additionally,SHAP analysis of the independent variables in the algorithm reveals distinct influencing trends under different performance labels.The workflow demonstrates the feasibility of incorporating performance prediction in the early design stage of village courtyards,significantly enhancing the efficiency of feedback and follow-up between design decision-making and performance evaluation.展开更多
Buildings in seismic-prone regions are highly vulnerable to structural damage,necessitating meticulous Seismic Damage Assessment(SDA)for accurate design and mitigation strategies.The intricate nature of Seismic Damage...Buildings in seismic-prone regions are highly vulnerable to structural damage,necessitating meticulous Seismic Damage Assessment(SDA)for accurate design and mitigation strategies.The intricate nature of Seismic Damage Assessment(SDA)poses challenges,particularly when employing Finite Element Analysis(FE)for individual structures,as simulation techniques are time-intensive due to the inherent complexity of the models.Compu-tational methods combining Soil-Structure Interaction(SSI)for earthquake damage assessment further com-pound the challenge,requiring substantial computational efforts to construct a comprehensive database for area-based prediction models.This study introduces such challenges via a novel Artificial Neural Network(ANN)approaches-based model as an alternative for prompt building Seismic Damage Assessment evaluation.The proposed ANN model leverages three key inputs-seismic,building,and soil parameters-incorporating a multi-step analysis process to generate seismic responses with soil-structure interaction.The findings underscore the remarkable accuracy of the SDA-Net model,positioning it as an effective predictive tool and rapid decision support system for structures affected by SSI impacts.This innovative approach not only serves as a proactive pre-disaster management tool for assessing potential damage but also emerges as a practical asset for ensuring the safety and durability of structures in the face of natural disasters.The study’s contribution lies in its potential application as a valuable tool in structural engineering,aligning with the objectives and scope of the Research Journal of The Institution of Structural Engineers.展开更多
The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI...The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI-MS） is investigated. The improved HPLC-ELSD method for the separation and quantitation of commercial and synthesized sucrose esters is described. Samples are analyzed by means of a reversed-phase （RP） HPLC using a Hypersil C8 column （250 mm× 4.6 mm, 5 μm particle size） with methanol-tetrahydrofuran （vo）ume ratio of 90 ： 10） and water under gradientcondition as the mobile phase, in which the flow rate is 1.0 ml·min^-1 and the column temperature is set at 40℃. This procedure provides a complete separation and determination ot monoester, diester, triester and higher esters with different acyl chain lengths in each fraction by a single run, in combination with the ESI-MS technology. With this method, it is possible to determine the approximate compositions of monoto polyesters in one analysis and quantitate pure positional isomers precisely using an external standard method. It is found that the method of ESI-MS coupling with HPLC system for the analysis of sucrose esters is straight forward, rapid and inexpensive, and can be readily applied in synthesis, purification and structure studies.展开更多
With the increased demand from the storage of renewable energy sources,some safe and inexpensive energy storage technologies instead of Li-ion batteries become urgently needed.Therefore,K-ion batteries(KIBs)have attra...With the increased demand from the storage of renewable energy sources,some safe and inexpensive energy storage technologies instead of Li-ion batteries become urgently needed.Therefore,K-ion batteries(KIBs)have attracted much attention and evolved significant development because of the low price,safety,and similar property compared with Li-ion batteries.Due to the high reversibility,stability,and low potential plateau,graphite becomes a current research focus and is regarded as one of the most promising KIB’s anode materials.In this review,we mainly discuss the electrochemical reaction mechanism of graphite during potassiation-depotassiation process and analyze the effects of electrode/electrolyte interface on graphite for Kion storage.Besides,we summarize several kinds of methods to improve the performance of graphite for KIBs,including the design of graphite structure,selection of appropriate binder,solvent chemistry,and salt chemistry.Meanwhile,a concept of“relative energy density”is raised,which can be more accurate to evaluate the genuine electrochemical performance of graphite anode involving the specific capacity and potential.In addition,we also summarize the considerable challenges to current graphite anode in KIBs and we believe our work will offer alterative solutions to further explore high-performance graphite anode of K-ion storage.展开更多
In this work, we investigate the methods to improve the performance of the swept source at 1.0 μm based on a polygon scanner, including in-cavity parameters and booster structures out of the cavity. The three in-cavi...In this work, we investigate the methods to improve the performance of the swept source at 1.0 μm based on a polygon scanner, including in-cavity parameters and booster structures out of the cavity. The three in-cavity parameters are the cavity length, the rotating speed of the polygon scanner, and the in-cavity energy. With the decrease of cavity length, the spectrum bandwidth becomes wider and the duty cycle becomes higher.With the increase of the rotating speed of the polygon, the spectrum bandwidth becomes narrower, and the duty cycle becomes lower but the repetition rate becomes higher. With more energy in-cavity, the spectrum bandwidth becomes wider and the duty cycle becomes higher. The booster structures include the buffered structure, secondary amplifier, and dual-semiconductor optical amplifier configuration, which are used to increase the sweep frequency to 86 kHz, the output power to 18 mW, and the tuning bandwidth to 131 nm, respectively.展开更多
Surface miner, a continuous mining machine, is being manufactured in India and abroad owing to enhanced demand of production in various mining industries like coal, limestone, gypsum, bauxite etc. Different types of s...Surface miner, a continuous mining machine, is being manufactured in India and abroad owing to enhanced demand of production in various mining industries like coal, limestone, gypsum, bauxite etc. Different types of surface miners are manufactured today based on cutting drum placement and design specifications. Selective mining without drilling and blasting, high production and small size products are some of the prominent attractive features obtained with these moving marvels. This machine can be used with good efficiency in soft to medium hard rock (100-120 MPa). This paper synthesizes the different applications, equipment models, features offered, operating methods, cutting performance assessment models as well as typical production performance of surface miner in coal and limestone mines of India. Engine hour metre reading, diesel and pick consumptions are linearly influenced by production. The emphasis for future research is also brought out.展开更多
Evaluation of method performance involves the consideration of numerous factors that can contribute to error.A variety of measures of performance can be borrowed from the signal detection literature and others are dra...Evaluation of method performance involves the consideration of numerous factors that can contribute to error.A variety of measures of performance can be borrowed from the signal detection literature and others are drawn from statistical science.This article demonstrates the principles of performance evaluation by applying multiple measures to osteometric sorting models for paired elements run against data from known individuals.Results indicate that false positive rates are close,on average,to expected values.As assemblage size grows,the false positive rate becomes unimportant and the false negative rate becomes significant.Size disparity among the commingled individuals plays a significant role in method performance,showing that case-specific circumstances(e.g.assemblage size and size disparity)will determine method power.展开更多
It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunh...It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunhofer diffraction system, it is concluded that the X-ray focusing system can be regarded as a kind of Praunhofer diffraction system. Therefore, a method based on Fourier spectrum analysis is presented to predict the intensity distribution in the focusing plane for the X-ray lenses. A brief analysis on the relationship between the parameters of X-ray lenses and their focusing performance is also given in this paper.展开更多
Prom investigation of the advantages and disadvantages of conventional tri-voltage method,a method for the measurement of the transmitting transducer＇s impedance was presented to solve the difficult problem of examin...Prom investigation of the advantages and disadvantages of conventional tri-voltage method,a method for the measurement of the transmitting transducer＇s impedance was presented to solve the difficult problem of examining the consistency of the transmitting phased array on the single-mode excitation sea spot.In the method based on the system function, the circuit structure of tri-voltage method was used but new parameters were measured.The principle of the method was given first.Then when resistors with different nominal values were used in the circuit,the measured results for the impedance of transducers were reported.The results were compared with the higher precision impedance analyzer.Finally,the error analysis was performed according to the impedance formula and the equivalent circuit parameters were fitted.Under the condition of guaranteeing the sampling precision,by performance analyzing, the resistor value in series was chosen relatively smaller than the impedance of transducer,the measurement of impedance could achieve the same precision as the higher precision impedance analyzer.Finally,the least squares curve-fitting of measured curves indicated that the transducer equivalent electrical parameters could be extracted accurately and used to design the matching network.展开更多
A semi-analytical/numerical model based on the multiple scattering （MS） method has been established for analyzing the effect of acoustic performance on main energy attenua- tion mechanism in viscoelastic coating con...A semi-analytical/numerical model based on the multiple scattering （MS） method has been established for analyzing the effect of acoustic performance on main energy attenua- tion mechanism in viscoelastic coating containing axisymmetric cavities. The basic functions of stress and displacement of the axisymmetric cavity surface are derived in the system of spheri- cal coordinates. The transition matrix between the incident wave and the scattering wave are obtained by the numerical integral of the basic functions of the cavity surface. The reflection, transmission and absorption performance of viscoelastic materials containing periodic cavities are calculated using the MS method and the wave propagating theory of the multi-layered medium. The results indicate that low frequency energy is mainly attenuated through cavity resonance. The resonant properties are found to be very sensitive to the boundary conditions. The coupling of the double-cavity is capable of extending the absorption to even lower fre- quencies. The absorption performance of the viscoelastic coating in the high frequency range is independent of the backing material. Its energy attenuation depends mainly on acoustic properties of cavity scattering and mode conversion.展开更多
Based on the results of slot milling experiments on the DD5 Ni-based single crystal superalloy(001) crystal plane along the [110]crystal direction, in this paper, efforts were devoted to investigate the tool wear proc...Based on the results of slot milling experiments on the DD5 Ni-based single crystal superalloy(001) crystal plane along the [110]crystal direction, in this paper, efforts were devoted to investigate the tool wear process, wear mechanism and failure modes of the physical vapor deposition(PVD)-AlTiN and TiAlN coated tools under dry milling and water-based minimum quantity lubrication(MQL) conditions. The scanning electron microscope(SEM) morphological observation and energy dispersive X-ray spectroscopy(EDX) elements analysis methods were adopted. Moreover, under the water-based MQL condition, the surface integrity such as surface roughness, dimensional and shape accuracy, microhardness and microstructure alteration were researched. The results demonstrated that the tool edge severe adhesion with the work material, induced by the high Al content in the PVD-AlTiN coating caused the catastrophic tool tip fracture. In contrast, the PVD-TiAlN tool displayed a steady and uniform minor flank wear, even though the material peeling and slight chipping also occurred in the final stage. In addition, due to the high effective cooling and lubricating actions of the water-based MQL method, the PVD-TiAlN coated tool demonstrated intact tip geometry; consequently it could be repaired and reused even if the failure criterion was attained. Moreover, as the accumulative milling length and the tool wear increased, all indicators of the surface integrity forehand were deteriorated.展开更多
基金supported by the National Natural Science Foundation of China (No.61876167)the Natural Science Foundation of Zhejiang Province (No.LY20F030017)。
文摘Simultaneous localization and mapping(SLAM) technology is a research hotspot in the field of intelligent mobile robot, and many researchers have developed many classic systems in the past few decades. However, most of the existing SLAM methods assume that the environment of the robot is static, which results in the performance of the system being greatly reduced in the dynamic environment. To solve this problem, a new dynamic object detection method based on point cloud motion analysis is proposed and incorporated into ORB-SLAM2. First, the method is regarded as a preprocessing stage, detecting moving objects in the scene, and then removing the moving objects to enhance the performance of the SLAM system. Experiments performed on a public RGB-D dataset show that the motion cancellation method proposed in this paper can effectively improve the performance of ORB-SLAM2 in a highly dynamic environment.
基金Supported by the National Natural Science Foundation of China （Grant No. 41176074） China Postdoctoral Science Foundation （Grant No.2012M512133） Specialized Research Fund for the Doctoral Program of Higher Education （Grant No.20102304120026）
文摘In order to study cavitation characteristics of a 2-D hydrofoil, the method that combines nonlinear cavitation model and mixed-iteration is used to predict and analyze the cavitation performance of hydrofoils. The cavitation elements are nonlinearly disposed based on the Green formula and perturbation potential panel method. At the same time, the method that combines cavity shape for fixed cavity length （CSCL） iteration and cavity shape for fixed cavitation number （CSCN） iteration is used to work out the thickness and length of hydrofoil cavitations. Through analysis of calculation results, it can be concluded that the jump of pressure and velocity potentially exist between cavitation end area and non-cavitations area on suction surface when cavitation occurs on hydrofoil. In certain angles of attack, the cavitation number has a negative impact on the length of cavitations. And under the same angle of attack and cavitation number, the bigger the thickness of the hydrofoil, the shorter the cavitations length.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences under Grant No XDA09020402the National Key Basic Research Program of China under Grant Nos 2013CBA01900,2010CB934300,2011CBA00607,and 2011CB932804+2 种基金the National Integrate Circuit Research Program of China under Grant No 2009ZX02023-003the National Natural Science Foundation of China under Grant Nos 61176122,61106001,61261160500,and 61376006the Science and Technology Council of Shanghai under Grant Nos 12nm0503701,13DZ2295700,12QA1403900,and 13ZR1447200
文摘A novel slow-down set waveform is proposed to improve the set performance and a 1 kb phase change random access memory chip fabricated with a 13nm CMOS technology is implemented to investigate the set performance by different set programming strategies based on this new set pulse. The amplitude difference （I1 - I2） of the set pulse is proved to be a crucial parameter for set programming. We observe and analyze the cell characteristics with different I1 - I2 by means of thermal simulations and high-resolution transmission electron microscopy, which reveal that an incomplete set programming will occur when the proposed slow-down pulse is set with an improperly high I1 - I2. This will lead to an amorphous residue in the active region. We also discuss the programming method to avoid the set performance degradations.
文摘Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food production, Sudan Dyes are banned to be used as food dyes in our country.
文摘A technology called solar energy is a very promising technique, and is considered as the cleanest and the most abundant renewable resource that is naturally available every day. In this paper, a MATLAB environment has been developed to calculate real-time power incidence on a PV system. It takes into account the time, location, PV tilt, and azimuth angles, and weather conditions to estimate incident power. In this paper, one case study is considered at New York State location. It has been applied to a newly installed 8 kW residential system located in Inwood. The solar panels are made up of silicon HIT (Heterojunction with Intrinsic Thin Layer) cells by Panasonic and solar cell rated at 19%. The result shows that the system is performing at its rated efficiency. The calculations involve the determination of direct, diffused and reflected radiation on the panels taking into account the time of the day, location, PV area, and orientations and weather conditions. The cloudiness index may be estimated based on the weather data and included in the calculations. After performing the irradiance calculations, the output power is estimated based on the rated efficiency at its temperature and compared with the generated output power. The real-time assessment of a PV system performance, during the operational time monitors the health of the PV system. The data obtained by this calculator may accompany production data provided to the consumer by the utility company.
基金supported by the National Social Science Fundation of China(Grant No.15CGL048)。
文摘This paper puts forward the connotation of enterprise green management and green management performance evaluation,analyzes the characteristics of enterprise green management performance evaluation and decomposes its content.Using the triple performance method,the paper constructs the performance evaluation index system of enterprise green management.Taking BH Petrochemical Co.,Ltd.at the high-efficiency ecological economic zone of the Yellow River Delta as an example,by using analytic hierarchy process(AHP)and Matlab programming,this paper determines the weight of each index in the enterprise green management performance evaluation index system,the fuzzy comprehensive evaluation method is used to evaluate the green management performance evaluation of industrial enterprises.The results show that the performance evaluation index system of enterprise green management constructed by"triple performance method"has important theoretical significance and application value for evaluating and guiding enterprises to strengthen their green management.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51407197,51522606,51336011,91541120,and 11472306)
文摘Plasma synthetic jet actuator（PSJA） has a wide application prospect in the high-speed flow control field for its high jet velocity.In this paper,the influence of the air pressure on the performance of a two-electrode PSJA is investigated by the schlieren method in a large range from 7 k Pa to 100 k Pa.The energy consumed by the PSJA is roughly the same for all the pressure levels.Traces of the precursor shock wave velocity and the jet front velocity vary a lot for different pressures.The precursor shock wave velocity first decreases gradually and then remains at 345 m/s as the air pressure increases.The peak jet front velocity always appears at the first appearance of a jet,and it decreases gradually with the increase of the air pressure.A maximum precursor shock wave velocity of 520 m/s and a maximum jet front velocity of 440 m/s are observed at the pressure of 7 k Pa.The averaged jet velocity in one period ranges from 44 m/s to 54 m/s for all air pressures,and it drops with the rising of the air pressure.High velocities of the precursor shock wave and the jet front indicate that this type of PSJA can still be used to influence the high-speed flow field at 7 k Pa.
基金This work was supported by the Scientific Research Projects of Tianjin Educational Committee(No.2020KJ029)。
文摘The prediction process often runs with small samples and under-sufficient information.To target this problem,we propose a performance comparison study that combines prediction and optimization algorithms based on experimental data analysis.Through a large number of prediction and optimization experiments,the accuracy and stability of the prediction method and the correction ability of the optimization method are studied.First,five traditional single-item prediction methods are used to process small samples with under-sufficient information,and the standard deviation method is used to assign weights on the five methods for combined forecasting.The accuracy of the prediction results is ranked.The mean and variance of the rankings reflect the accuracy and stability of the prediction method.Second,the error elimination prediction optimization method is proposed.To make,the prediction results are corrected by error elimination optimization method(EEOM),Markov optimization and two-layer optimization separately to obtain more accurate prediction results.The degree improvement and decline are used to reflect the correction ability of the optimization method.The results show that the accuracy and stability of combined prediction are the best in the prediction methods,and the correction ability of error elimination optimization is the best in the optimization methods.The combination of the two methods can well solve the problem of prediction with small samples and under-sufficient information.Finally,the accuracy of the combination of the combined prediction and the error elimination optimization is verified by predicting the number of unsafe events in civil aviation in a certain year.
文摘An analytical method was developed and validated for determination of patulin in apple puree by HPLC. Extraction and clean-up ofpatulin from clear extract are achieved on AFFINIMIP SPEPATULIN cartridges. Patulin is then separated on a Hypersil GOLD column 150 mm × 4 mm, 5 μtmand detected at 276 nm. The recovery in the range of 5 μg/kg-80 μg/kg was 81.47%. The limit of detection （LOD） was 1.36 μg/kg, and the limit of quantification （LOQ） was 4.55 μg/kg. The patulin content of the commercial samples of apple puree and samples of apple and fruit puree forinfants and young children as well as the samples of apple puree prepared from two apple varieties intended for processing （Jonathan, Florina） and obtained from conventional and uncertified organic cultures has been evaluated in this paper. The 44.83% patulin concentration of the analyzed samples were under the maximum level of the European Commission Regulation （EC） 1881/2006, in 46.55% of the analyzed samples patulin was not detected and in 8.62% of samples patulin concentration was lower than LOQ （European Comission, 2006a） Patulin was not detected in samples of apple puree intended for infants and young children consumption.
基金funded by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX19_0090).
文摘To address the insufficient integration of performance evaluation and contextual analysis in traditional architectural design,this paper proposes a design workflow that combines data-driven and performance-driven approaches,establishing a comprehensive operational pathway from typology selection and design generation to performance assessment.Using Yanshen Ancient Town,a cold region,as the study area,the research evaluates 18 traditional courtyard types and 8 brick kiln courtyard types.Benchmark models are selected based on the combined performance of PET(Physiological Equivalent Temperature)and MRT(Mean Radiant Temperature)indices.Subsequently,multiple performance indicators,including indoor and outdoor thermal comfort,indoor illuminance,and building energy consumption,are integrated into the analysis.Using a genetic algorithm,Pareto optimal solutions that meet performance requirements are iteratively optimized and filtered.Based on the learning rates and various evaluation indicators,XGBoost is ultimately selected to classify and predict the overall building performance.Results indicate that the model achieves an average prediction accuracy of 83.6%.Additionally,SHAP analysis of the independent variables in the algorithm reveals distinct influencing trends under different performance labels.The workflow demonstrates the feasibility of incorporating performance prediction in the early design stage of village courtyards,significantly enhancing the efficiency of feedback and follow-up between design decision-making and performance evaluation.
文摘Buildings in seismic-prone regions are highly vulnerable to structural damage,necessitating meticulous Seismic Damage Assessment(SDA)for accurate design and mitigation strategies.The intricate nature of Seismic Damage Assessment(SDA)poses challenges,particularly when employing Finite Element Analysis(FE)for individual structures,as simulation techniques are time-intensive due to the inherent complexity of the models.Compu-tational methods combining Soil-Structure Interaction(SSI)for earthquake damage assessment further com-pound the challenge,requiring substantial computational efforts to construct a comprehensive database for area-based prediction models.This study introduces such challenges via a novel Artificial Neural Network(ANN)approaches-based model as an alternative for prompt building Seismic Damage Assessment evaluation.The proposed ANN model leverages three key inputs-seismic,building,and soil parameters-incorporating a multi-step analysis process to generate seismic responses with soil-structure interaction.The findings underscore the remarkable accuracy of the SDA-Net model,positioning it as an effective predictive tool and rapid decision support system for structures affected by SSI impacts.This innovative approach not only serves as a proactive pre-disaster management tool for assessing potential damage but also emerges as a practical asset for ensuring the safety and durability of structures in the face of natural disasters.The study’s contribution lies in its potential application as a valuable tool in structural engineering,aligning with the objectives and scope of the Research Journal of The Institution of Structural Engineers.
基金Supported by the National Natural Science Foundation of China （20906052）, the Science Foundation of Nantong City Municipality （K2007011, K2008023）, the Science Foundation of Nantong University （08R08） and the University Science Research Project of Jiangsu Province （09KJB530008）.
文摘The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI-MS） is investigated. The improved HPLC-ELSD method for the separation and quantitation of commercial and synthesized sucrose esters is described. Samples are analyzed by means of a reversed-phase （RP） HPLC using a Hypersil C8 column （250 mm× 4.6 mm, 5 μm particle size） with methanol-tetrahydrofuran （vo）ume ratio of 90 ： 10） and water under gradientcondition as the mobile phase, in which the flow rate is 1.0 ml·min^-1 and the column temperature is set at 40℃. This procedure provides a complete separation and determination ot monoester, diester, triester and higher esters with different acyl chain lengths in each fraction by a single run, in combination with the ESI-MS technology. With this method, it is possible to determine the approximate compositions of monoto polyesters in one analysis and quantitate pure positional isomers precisely using an external standard method. It is found that the method of ESI-MS coupling with HPLC system for the analysis of sucrose esters is straight forward, rapid and inexpensive, and can be readily applied in synthesis, purification and structure studies.
基金supports from the National Natural Science Foundation of China(51772135,52002115)the Fundamental Research Funds for the Central Universities(21617330)Science and Technology Development Project of Henan Province(212102210487)。
文摘With the increased demand from the storage of renewable energy sources,some safe and inexpensive energy storage technologies instead of Li-ion batteries become urgently needed.Therefore,K-ion batteries(KIBs)have attracted much attention and evolved significant development because of the low price,safety,and similar property compared with Li-ion batteries.Due to the high reversibility,stability,and low potential plateau,graphite becomes a current research focus and is regarded as one of the most promising KIB’s anode materials.In this review,we mainly discuss the electrochemical reaction mechanism of graphite during potassiation-depotassiation process and analyze the effects of electrode/electrolyte interface on graphite for Kion storage.Besides,we summarize several kinds of methods to improve the performance of graphite for KIBs,including the design of graphite structure,selection of appropriate binder,solvent chemistry,and salt chemistry.Meanwhile,a concept of“relative energy density”is raised,which can be more accurate to evaluate the genuine electrochemical performance of graphite anode involving the specific capacity and potential.In addition,we also summarize the considerable challenges to current graphite anode in KIBs and we believe our work will offer alterative solutions to further explore high-performance graphite anode of K-ion storage.
基金National Natural Science Foundation of China(NSFC)(61327004,61377037,61378028,61378090,61421002,61435003,61505036)
文摘In this work, we investigate the methods to improve the performance of the swept source at 1.0 μm based on a polygon scanner, including in-cavity parameters and booster structures out of the cavity. The three in-cavity parameters are the cavity length, the rotating speed of the polygon scanner, and the in-cavity energy. With the decrease of cavity length, the spectrum bandwidth becomes wider and the duty cycle becomes higher.With the increase of the rotating speed of the polygon, the spectrum bandwidth becomes narrower, and the duty cycle becomes lower but the repetition rate becomes higher. With more energy in-cavity, the spectrum bandwidth becomes wider and the duty cycle becomes higher. The booster structures include the buffered structure, secondary amplifier, and dual-semiconductor optical amplifier configuration, which are used to increase the sweep frequency to 86 kHz, the output power to 18 mW, and the tuning bandwidth to 131 nm, respectively.
文摘Surface miner, a continuous mining machine, is being manufactured in India and abroad owing to enhanced demand of production in various mining industries like coal, limestone, gypsum, bauxite etc. Different types of surface miners are manufactured today based on cutting drum placement and design specifications. Selective mining without drilling and blasting, high production and small size products are some of the prominent attractive features obtained with these moving marvels. This machine can be used with good efficiency in soft to medium hard rock (100-120 MPa). This paper synthesizes the different applications, equipment models, features offered, operating methods, cutting performance assessment models as well as typical production performance of surface miner in coal and limestone mines of India. Engine hour metre reading, diesel and pick consumptions are linearly influenced by production. The emphasis for future research is also brought out.
文摘Evaluation of method performance involves the consideration of numerous factors that can contribute to error.A variety of measures of performance can be borrowed from the signal detection literature and others are drawn from statistical science.This article demonstrates the principles of performance evaluation by applying multiple measures to osteometric sorting models for paired elements run against data from known individuals.Results indicate that false positive rates are close,on average,to expected values.As assemblage size grows,the false positive rate becomes unimportant and the false negative rate becomes significant.Size disparity among the commingled individuals plays a significant role in method performance,showing that case-specific circumstances(e.g.assemblage size and size disparity)will determine method power.
基金This work was performed with the support from the National Natural Science Foundation of China (No. 10174079) the fund for the qualified researchers in Zhejiang University of Technology, P. R. China.
文摘It is important to predict the intensity distribution in focusing plane for designing the X-ray compound refractive lenses. On the basis of analyzing the structure of X-ray compound lenses and comparing it with Praunhofer diffraction system, it is concluded that the X-ray focusing system can be regarded as a kind of Praunhofer diffraction system. Therefore, a method based on Fourier spectrum analysis is presented to predict the intensity distribution in the focusing plane for the X-ray lenses. A brief analysis on the relationship between the parameters of X-ray lenses and their focusing performance is also given in this paper.
基金supported by the National Natural Science Foundation of China(11004214,10574137)
文摘Prom investigation of the advantages and disadvantages of conventional tri-voltage method,a method for the measurement of the transmitting transducer＇s impedance was presented to solve the difficult problem of examining the consistency of the transmitting phased array on the single-mode excitation sea spot.In the method based on the system function, the circuit structure of tri-voltage method was used but new parameters were measured.The principle of the method was given first.Then when resistors with different nominal values were used in the circuit,the measured results for the impedance of transducers were reported.The results were compared with the higher precision impedance analyzer.Finally,the error analysis was performed according to the impedance formula and the equivalent circuit parameters were fitted.Under the condition of guaranteeing the sampling precision,by performance analyzing, the resistor value in series was chosen relatively smaller than the impedance of transducer,the measurement of impedance could achieve the same precision as the higher precision impedance analyzer.Finally,the least squares curve-fitting of measured curves indicated that the transducer equivalent electrical parameters could be extracted accurately and used to design the matching network.
基金supported by the National Nature Science Foundation of China(11104310)the 973 National key Basic Research Program of China(2013CB632900)the 863 National High Technology Program of China(2011AA11A103)
文摘A semi-analytical/numerical model based on the multiple scattering （MS） method has been established for analyzing the effect of acoustic performance on main energy attenua- tion mechanism in viscoelastic coating containing axisymmetric cavities. The basic functions of stress and displacement of the axisymmetric cavity surface are derived in the system of spheri- cal coordinates. The transition matrix between the incident wave and the scattering wave are obtained by the numerical integral of the basic functions of the cavity surface. The reflection, transmission and absorption performance of viscoelastic materials containing periodic cavities are calculated using the MS method and the wave propagating theory of the multi-layered medium. The results indicate that low frequency energy is mainly attenuated through cavity resonance. The resonant properties are found to be very sensitive to the boundary conditions. The coupling of the double-cavity is capable of extending the absorption to even lower fre- quencies. The absorption performance of the viscoelastic coating in the high frequency range is independent of the backing material. Its energy attenuation depends mainly on acoustic properties of cavity scattering and mode conversion.
基金supported by the National Natural Science Foundation of China(Grant No.51375082)
文摘Based on the results of slot milling experiments on the DD5 Ni-based single crystal superalloy(001) crystal plane along the [110]crystal direction, in this paper, efforts were devoted to investigate the tool wear process, wear mechanism and failure modes of the physical vapor deposition(PVD)-AlTiN and TiAlN coated tools under dry milling and water-based minimum quantity lubrication(MQL) conditions. The scanning electron microscope(SEM) morphological observation and energy dispersive X-ray spectroscopy(EDX) elements analysis methods were adopted. Moreover, under the water-based MQL condition, the surface integrity such as surface roughness, dimensional and shape accuracy, microhardness and microstructure alteration were researched. The results demonstrated that the tool edge severe adhesion with the work material, induced by the high Al content in the PVD-AlTiN coating caused the catastrophic tool tip fracture. In contrast, the PVD-TiAlN tool displayed a steady and uniform minor flank wear, even though the material peeling and slight chipping also occurred in the final stage. In addition, due to the high effective cooling and lubricating actions of the water-based MQL method, the PVD-TiAlN coated tool demonstrated intact tip geometry; consequently it could be repaired and reused even if the failure criterion was attained. Moreover, as the accumulative milling length and the tool wear increased, all indicators of the surface integrity forehand were deteriorated.
