The slip-sweep technique is one of the high-efficiency, high-fidelity, and environmental vibroseis seismic prospecting techniques which consists of a vibrator group sweeping without waiting for the previous group＇s s...The slip-sweep technique is one of the high-efficiency, high-fidelity, and environmental vibroseis seismic prospecting techniques which consists of a vibrator group sweeping without waiting for the previous group＇s sweep to terminate. The cycle time can be reduced drastically and hence the production efficiency can be increased significantly but harmonic distortion of one sweep will leak into the record of the other sweep. In this paper, we propose an anti-correlation method for removing harmonic distortion in vibroseis data. This method is based on decomposition of the ground force signal into fundamental and harmonic components. Then the corresponding anti-correlation operator can be computed to estimate the energy of each harmonic after correlating the vibroseis data with the corresponding harmonic component. Finally, the vibroseis harmonic noise to be removed can be obtained by subtracting the extracted harmonic noise from the traces of the previous group＇s sweep. The advantage of the proposed method is that it can process both uncorrelated and correlated vibroseis seismic data. Moreover, the algorithm is simple, stable, and computationally fast. Especially, the significant contribution of this method is a considerable reduction in the harmonic without any alteration of the desired signals. The method was tested on both synthetic and field data sets to validate the good harmonic noise suppression results.展开更多
[Objective] The research aimed at optimizing protein removal method and condition of polysaccharide extracts from Phellinus Linteus and comparing the effects of two methods on protein removal.[Method] Free proteins in...[Objective] The research aimed at optimizing protein removal method and condition of polysaccharide extracts from Phellinus Linteus and comparing the effects of two methods on protein removal.[Method] Free proteins in polysaccharide from Phellinus Linteus were removed using Sevag method and TCA method.[Result] The TCA method was better than Sevag method,and the optimum protein removal condition was treated with 5% TCA for 30 min and for three times,under that condition,the protein removal rate attained 82% while the polysaccharide loss rate was only 10.8%.[Conclusion] The TCA method was a better way to remove proteins of polysaccharide from Phellinus Linteus.展开更多
The Mn-Ce-Nb-O_x/P84 catalytic filter for removal of particulates and NO simultaneous was prepared by a novel method(foam coating method). The process parameters including the concentrations of PTFE emulsion, particle...The Mn-Ce-Nb-O_x/P84 catalytic filter for removal of particulates and NO simultaneous was prepared by a novel method(foam coating method). The process parameters including the concentrations of PTFE emulsion, particle size of catalyst and calcination temperature for preparation of catalytic filters were analyzed. In addition, the physical properties and performance for removal of NO(NH_3-SCR) and particulates of Mn-Ce-Nb-O_x/P84 catalytic filter prepared under the optimized parameters, were also systematic studied. Results show that the process parameters had significant influences on stability and performance of catalytic filter, The Mn-Ce-Nb-O_x/P84 catalytic filter prepared by foam coating method under the optimized parameters, has satisfactory physical properties and catalytic performance for removal of NO and particulates at 140-220 ℃. The NO removal efficiency of catalytic filter can reach95.3% at 200 ℃ as the catalyst loading amount is 450 g/m^2, Moreover,the dust removal efficiency of MnGe-Nb-O_x/P84 catalytic filter reaches as high as 99.98%, and the PM2.5 removal efficiency also reaches99.98%. The anti-sulfur performance of Mn-Ce-Nb-O_x catalytic filter is also attractive, after injecting150 ppm SO_2, the NO removal efficiency still retains up to 85%. It is indicated that the foam coating method can not only make a bond of high strength between catalyst and filter, but also make the catalytic filter possessing an excellent and stable performance for removal of NO and particulates.展开更多
The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predi...The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.展开更多
In order to develop an effective MIBK removal method of H 2TaF 7 solution in tantalum extraction process, MIBK removal from aqueous solution by the aeration method was investigated by using an aeration column with the...In order to develop an effective MIBK removal method of H 2TaF 7 solution in tantalum extraction process, MIBK removal from aqueous solution by the aeration method was investigated by using an aeration column with the dimensions of 78 mm in inner diameter and 1 100 mm in length. The effects of aeration conditions on aerating efficiency were investigated in the ranges of temperature 303 333 K, airflow rate 50 300 L/h,volume of solution 1 600 3 200 mL. Aerating efficiency increases with the increase of temperature and airflow rate. MIBK in aqueous solution can be removed from 0.058 mol/L to 0.002 mol/L at 50 ℃,airflow rate 200 L/h, volume of solution 2 400 mL and aeration time 1h. The experimental results show that MIBK can be removed effectively from aqueous solution by the aeration method.展开更多
This paper develops a variational model for image noise removal using total curvature(TC), which is a high-order regularizer. The TC has the advantage of preserving image feature. Unfortunately, it also has the charac...This paper develops a variational model for image noise removal using total curvature(TC), which is a high-order regularizer. The TC has the advantage of preserving image feature. Unfortunately, it also has the characteristics of nonlinear, non-convex and non-smooth. Consequently, the numerical computation with the curvature regularization is difficult. In order to conquer the computation problem, the proposed model is transformed into an alternating optimization problem by importing auxiliary variables. Furthermore, based on alternating direction method of multipliers, we design a fast numerical approximation iterative scheme for proposed model. Finally, numerous experiments are implemented to indicate the advantages of the proposed model in image edge preserving, image contrast and corners preserving. Meanwhile, the high computational efficiency of the designed model is verified by comparing with traditional models, including the total variation(TV) and total Laplace(TL) model.展开更多
The objectives of this study were to evaluate growth, yield and nutrients removal of five cassava cultivars planted by different planting methods in late rainy season of northeastern Thailand. A split plot design was ...The objectives of this study were to evaluate growth, yield and nutrients removal of five cassava cultivars planted by different planting methods in late rainy season of northeastern Thailand. A split plot design was used in this study. The planting methods (vertical and horizontal) were assigned as main-plots. Cassava cultivars (Rayong-7, Rayong-11, Rayong-72, Huaybong-80 and E-dum) were assigned as sub-plots with four replications. Results showed that vertical planting gave significantly higher fresh storage root yield than those of horizontal planting, across five cassava cultivars. The cultivar Rayong-7 produced maximum fresh storage root yield across two planting methods, but not significantly different from Rayong 11, Huaybong 80 and Edum cultivars. Irrespective of nutrient removal, N, P and K removed ranges from 2.9 - 3.6, 0.8 - 1.3 and 5.3 - 7.9 kg per ton fresh root weight, respectively depending on cassava cultivar. The cultivar Rayong-7 removed the highest quantities of N, and the cultivar Rayong-11 removed maximum of P and K in the present study. Regardless of nutrient removal at different plant parts;N, P and K removed maximum quantities in leaf, stem and storage root, respectively. Planting method had no significant effect on N and P removal, but significant effect on K removal. The vertical planting removed K higher than those of horizontal planting.展开更多
[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dos...[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.展开更多
[Objectives] To optimize the ethyl acetate impurity removal method for extracting and isolating mangiferin from mango leaves,and provide raw materials and technical support for development and use of mangiferin relate...[Objectives] To optimize the ethyl acetate impurity removal method for extracting and isolating mangiferin from mango leaves,and provide raw materials and technical support for development and use of mangiferin related products. [Methods]Five steps( material crushing→ ethyl acetate impurity removing → concentrated extract washing → extracting with methanol → crystallization and precipitation) were used.The single factor experiment and L9( 34) orthogonal experiment was carried out to optimize the process parameters including extraction time,ultrasonic power,extraction times,and extraction temperature.[Results] The optimum process of ethyl acetate impurity removal method for extracting and isolating mangiferin from mango leaves was as follows: the mango leaves were crushed and sieved; 3 m L/g of ethyl acetate was added,sealed and soaked for 4 h,ultrasonically shaken for 20 min( 50℃,350 W),filtered at room temperature,filtered with 100 mesh sieve,and extracted three times; added 100% methanol to the residue at 3 m L/g,extract by ultrasonic vibration for 20 min( 350 W,55℃)for four times,filtered with 100 mesh sieve when it was still hot; mixed the extract of each time,condensed by vacuum decompression to get the extract; added 100% methanol at 4 m L/g,mixed and washed for 5 min at room temperature,placed for 10 min,filtered with 100 mesh sieve,washed 3 times repeatedly,and dried the filter residue at 60℃ to obtain the crude mangiferin; added 100% methanol at 4 m L/g,mixed and washed at 50℃ for 5 min,placed at 6℃ for 8 h,dried the filter residue at 60℃,and repeatedly crystallized two times. According to the above process,crude and pure mangiferin products could be obtained,the purity of mangiferin of the crude product was higher than 64. 00%,the total recovery rate was 83. 90%,and the purity of mangiferin of the pure product was higher than 98. 00%,and the total recovery rate was about 66. 40%. [Conclusions] The optimized ethyl acetate impurity removal method is easy in operation,low in cost,and high in efficiency for extracting and isolating mangiferin,and can be applied for actual production of mangiferin.展开更多
The tube inside and outside heat transfer mechanism of Passive Residual Heat Removal Heat Exchanger (PRHR HX) was analyzed. The calculation method of this special heat exchanger under natural convection condition in I...The tube inside and outside heat transfer mechanism of Passive Residual Heat Removal Heat Exchanger (PRHR HX) was analyzed. The calculation method of this special heat exchanger under natural convection condition in In-containment Refueling Water Storage Tank (IRWST) was carried out. The single-tube coupling model three-dimensional natural circulation in the IRWST was simulated numerically using Fluent. The heat transfer and flow characteristics of the fluid in IRWST were obtained. The comparison of the results between theoretical arithmetic and numerical simulation showed that the theoretical calculation method is suitable for the heat transfer calculation of PRHR HX.展开更多
Trapezoidal pulse shaping algorithm is widely applied to improve signal-to-noise ratio(SNR), throughput and energy resolution with the properties of noise suppression, pile-up pulse separation and ballistic deficit co...Trapezoidal pulse shaping algorithm is widely applied to improve signal-to-noise ratio(SNR), throughput and energy resolution with the properties of noise suppression, pile-up pulse separation and ballistic deficit correction. The algorithm can be acquired by z transform method which is easier for derivation. However, the baseline drift of trapezoidal pulse appears because the noise superimposes on the input signal. In this paper,two new methods based on convergence analysis and noise suppression are proposed to remove the baseline drift resulting from trapezoidal pulse shaping. Simulations and experimental tests are carried out to verify the methods. The results demonstrate that the proposed methods can remove baseline drift in trapezoidal pulse shaping.展开更多
Compressed sensing(CS) has achieved great success in single noise removal. However, it cannot restore the images contaminated with mixed noise efficiently. This paper introduces nonlocal similarity and cosparsity insp...Compressed sensing(CS) has achieved great success in single noise removal. However, it cannot restore the images contaminated with mixed noise efficiently. This paper introduces nonlocal similarity and cosparsity inspired by compressed sensing to overcome the difficulties in mixed noise removal, in which nonlocal similarity explores the signal sparsity from similar patches, and cosparsity assumes that the signal is sparse after a possibly redundant transform. Meanwhile, an adaptive scheme is designed to keep the balance between mixed noise removal and detail preservation based on local variance. Finally, IRLSM and RACoSaMP are adopted to solve the objective function. Experimental results demonstrate that the proposed method is superior to conventional CS methods, like K-SVD and state-of-art method nonlocally centralized sparse representation(NCSR), in terms of both visual results and quantitative measures.展开更多
Thin-walled parts have low stiffness characteristic. Initial residual stress of thin-walled blanks is an important influence factor on machining stability. The present work is to verify the feasibility of an initial r...Thin-walled parts have low stiffness characteristic. Initial residual stress of thin-walled blanks is an important influence factor on machining stability. The present work is to verify the feasibility of an initial residual stress measurement of layer removal method. According to initial residual stress experiment for casting ZL205 A aluminum alloy tapered thin-walled blank by a common method,namely hole-drilling method,three finite element models with initial residual stress are established to simulate the layer removal method in ABAQUS and ANSYS software. By analyzing the results of simulation and experiments,the cutting residual stress inlayer removal process has a significant effect on measurement results. Reducing cutting residual stress is helpful to improve accuracy of layer removal method.展开更多
A conventional complex variable boundary integral equation （CVBIE） in plane elasticity is provided. After using the Somigliana identity between a particular fundamental stress field and a physical stress field, an a...A conventional complex variable boundary integral equation （CVBIE） in plane elasticity is provided. After using the Somigliana identity between a particular fundamental stress field and a physical stress field, an additional integral equality is obtained. By adding both sides of this integral equality to both sides of the conventional CVBIE, the amended boundary integral equation （BIE） is obtained. The method based on the discretization of the amended BIE is called the amended influence matrix method. With this method, for the Neumann boundary value problem （BVP） of an interior region, a unique solution for the displacement can be obtained. Several numerical examples are provided to prove the efficiency of the suggested method.展开更多
Shadow and variable illumination considerably influence the results of image understanding such as image segmentation, object tracking, and object recognition. The intrinsic image decomposition is to separate the refl...Shadow and variable illumination considerably influence the results of image understanding such as image segmentation, object tracking, and object recognition. The intrinsic image decomposition is to separate the reflectance and the illumination image from an observed image. The intrinsic image decomposition is very useful to remove shadows and then improve the performance of image understanding. In this paper, we present a new shadow removal method based on intrinsic image decomposition on a single color image using the Fisher Linear Discriminant (FLD). Under the assumptions-Lambertian surfaces, approximately Planckian lighting, and narrowband camera sensors, there exist an invariant image, which is 1-dimensional greyscale and independent of illuminant color and intensity. The Fisher Linear Discriminant is applied to create the invariant image. And further the shadows can be removed through the difference between invariant image and original color image. The experimental results on real data show good performance of this algorithm.展开更多
Residual stress is one of the factors affecting the machining deformation of monolithic structure parts in the aviation industry. Thus, the studies on machining deformation rules induced by residual stresses largely d...Residual stress is one of the factors affecting the machining deformation of monolithic structure parts in the aviation industry. Thus, the studies on machining deformation rules induced by residual stresses largely depend on correctly and efficiently measuring the residual stresses of workpieccs. A modified layer-removal method is proposed to measure residual stress by analysing the characteristics of a traditional, layer-removal method. The coefficients of strain release are then deduced according to the simulation results using the finite element method （FEM）. Moreover, the residual stress in a 7075T651 aluminium alloy plate is measured using the proposed method, and the results are then analyzed and compared with the data obtained by the traditional methods. The analysis indicates that the modified layer-removal method is effective and practical for measuring the residual stress distribution in pre-stretched aluminium alloy plates.展开更多
According to autopsy reports,patients who died from COVID-19 had a lot of mucus in the lung that obstructed the airways,reduced the effect of mechanical ventilation,and even led to pulmonary failure.Traditional Chines...According to autopsy reports,patients who died from COVID-19 had a lot of mucus in the lung that obstructed the airways,reduced the effect of mechanical ventilation,and even led to pulmonary failure.Traditional Chinese medicine literature mentions that"Inability to remove phlegm impair s the lung,which leads to death."Hence one of the most urgent problems to be solved is to remove phlegm from the small airways.This article elaborates ten methods to remove phlegm for clinical reference.展开更多
According to autopsy reports,patients who died from COVID‑19 had a lot of mucus in the lung that obstructed the airways,reduced the effect of mechanical ventilation,and even led to pulmonary failure.Traditional Chines...According to autopsy reports,patients who died from COVID‑19 had a lot of mucus in the lung that obstructed the airways,reduced the effect of mechanical ventilation,and even led to pulmonary failure.Traditional Chinese medicine literature mentions that“Inability to remove phlegm impairs the lung,which leads to death.”Hence one of the most urgent problems to be solved is to remove phlegm from the small airways.This article elaborates ten methods to remove phlegm for clinical reference.展开更多
:This article first analyzes the problems existing in the teaching about diagnosing and removing automobile’s failure,and then discusses some specific teaching strategies on diagnosing and removing automobile’s fail...:This article first analyzes the problems existing in the teaching about diagnosing and removing automobile’s failure,and then discusses some specific teaching strategies on diagnosing and removing automobile’s failure to provide some effective reference for the related staff.展开更多
基金supported by the Sinopec Service Company and China National Petroleum Corporation
文摘The slip-sweep technique is one of the high-efficiency, high-fidelity, and environmental vibroseis seismic prospecting techniques which consists of a vibrator group sweeping without waiting for the previous group＇s sweep to terminate. The cycle time can be reduced drastically and hence the production efficiency can be increased significantly but harmonic distortion of one sweep will leak into the record of the other sweep. In this paper, we propose an anti-correlation method for removing harmonic distortion in vibroseis data. This method is based on decomposition of the ground force signal into fundamental and harmonic components. Then the corresponding anti-correlation operator can be computed to estimate the energy of each harmonic after correlating the vibroseis data with the corresponding harmonic component. Finally, the vibroseis harmonic noise to be removed can be obtained by subtracting the extracted harmonic noise from the traces of the previous group＇s sweep. The advantage of the proposed method is that it can process both uncorrelated and correlated vibroseis seismic data. Moreover, the algorithm is simple, stable, and computationally fast. Especially, the significant contribution of this method is a considerable reduction in the harmonic without any alteration of the desired signals. The method was tested on both synthetic and field data sets to validate the good harmonic noise suppression results.
基金Supported by Youth Fund Project in Sichuan Province(2008ZQ026-072)Support Science and Technology Project of Sichuan Province(2008FZ0157)~~
文摘[Objective] The research aimed at optimizing protein removal method and condition of polysaccharide extracts from Phellinus Linteus and comparing the effects of two methods on protein removal.[Method] Free proteins in polysaccharide from Phellinus Linteus were removed using Sevag method and TCA method.[Result] The TCA method was better than Sevag method,and the optimum protein removal condition was treated with 5% TCA for 30 min and for three times,under that condition,the protein removal rate attained 82% while the polysaccharide loss rate was only 10.8%.[Conclusion] The TCA method was a better way to remove proteins of polysaccharide from Phellinus Linteus.
基金Project supported by the National Natural Science Foundation of China(21501097,21272118,21577065)the Natural Science Foundation of Jiangsu Province(BK20170954)+2 种基金the Startup Foundation for Introducing Talent of NUIST(2017r073)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China,China(18KJB430019)University Science Research Project of Jiangsu Province(18KJB430019)
文摘The Mn-Ce-Nb-O_x/P84 catalytic filter for removal of particulates and NO simultaneous was prepared by a novel method(foam coating method). The process parameters including the concentrations of PTFE emulsion, particle size of catalyst and calcination temperature for preparation of catalytic filters were analyzed. In addition, the physical properties and performance for removal of NO(NH_3-SCR) and particulates of Mn-Ce-Nb-O_x/P84 catalytic filter prepared under the optimized parameters, were also systematic studied. Results show that the process parameters had significant influences on stability and performance of catalytic filter, The Mn-Ce-Nb-O_x/P84 catalytic filter prepared by foam coating method under the optimized parameters, has satisfactory physical properties and catalytic performance for removal of NO and particulates at 140-220 ℃. The NO removal efficiency of catalytic filter can reach95.3% at 200 ℃ as the catalyst loading amount is 450 g/m^2, Moreover,the dust removal efficiency of MnGe-Nb-O_x/P84 catalytic filter reaches as high as 99.98%, and the PM2.5 removal efficiency also reaches99.98%. The anti-sulfur performance of Mn-Ce-Nb-O_x catalytic filter is also attractive, after injecting150 ppm SO_2, the NO removal efficiency still retains up to 85%. It is indicated that the foam coating method can not only make a bond of high strength between catalyst and filter, but also make the catalytic filter possessing an excellent and stable performance for removal of NO and particulates.
文摘The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.
文摘In order to develop an effective MIBK removal method of H 2TaF 7 solution in tantalum extraction process, MIBK removal from aqueous solution by the aeration method was investigated by using an aeration column with the dimensions of 78 mm in inner diameter and 1 100 mm in length. The effects of aeration conditions on aerating efficiency were investigated in the ranges of temperature 303 333 K, airflow rate 50 300 L/h,volume of solution 1 600 3 200 mL. Aerating efficiency increases with the increase of temperature and airflow rate. MIBK in aqueous solution can be removed from 0.058 mol/L to 0.002 mol/L at 50 ℃,airflow rate 200 L/h, volume of solution 2 400 mL and aeration time 1h. The experimental results show that MIBK can be removed effectively from aqueous solution by the aeration method.
基金supported by the National Natural Science Foundation of China(No.61602269)the China Postdoctoral Science Foundation(No.2015M571993)+1 种基金the Shandong Provincial Natural Science Foundation of China(No.ZR2017MD004)the Qingdao Postdoctoral Application Research Funded Project
文摘This paper develops a variational model for image noise removal using total curvature(TC), which is a high-order regularizer. The TC has the advantage of preserving image feature. Unfortunately, it also has the characteristics of nonlinear, non-convex and non-smooth. Consequently, the numerical computation with the curvature regularization is difficult. In order to conquer the computation problem, the proposed model is transformed into an alternating optimization problem by importing auxiliary variables. Furthermore, based on alternating direction method of multipliers, we design a fast numerical approximation iterative scheme for proposed model. Finally, numerous experiments are implemented to indicate the advantages of the proposed model in image edge preserving, image contrast and corners preserving. Meanwhile, the high computational efficiency of the designed model is verified by comparing with traditional models, including the total variation(TV) and total Laplace(TL) model.
文摘The objectives of this study were to evaluate growth, yield and nutrients removal of five cassava cultivars planted by different planting methods in late rainy season of northeastern Thailand. A split plot design was used in this study. The planting methods (vertical and horizontal) were assigned as main-plots. Cassava cultivars (Rayong-7, Rayong-11, Rayong-72, Huaybong-80 and E-dum) were assigned as sub-plots with four replications. Results showed that vertical planting gave significantly higher fresh storage root yield than those of horizontal planting, across five cassava cultivars. The cultivar Rayong-7 produced maximum fresh storage root yield across two planting methods, but not significantly different from Rayong 11, Huaybong 80 and Edum cultivars. Irrespective of nutrient removal, N, P and K removed ranges from 2.9 - 3.6, 0.8 - 1.3 and 5.3 - 7.9 kg per ton fresh root weight, respectively depending on cassava cultivar. The cultivar Rayong-7 removed the highest quantities of N, and the cultivar Rayong-11 removed maximum of P and K in the present study. Regardless of nutrient removal at different plant parts;N, P and K removed maximum quantities in leaf, stem and storage root, respectively. Planting method had no significant effect on N and P removal, but significant effect on K removal. The vertical planting removed K higher than those of horizontal planting.
文摘[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.
基金Supported by Key Technological Innovation Project of Sichuan Province,China(2016XM120)
文摘[Objectives] To optimize the ethyl acetate impurity removal method for extracting and isolating mangiferin from mango leaves,and provide raw materials and technical support for development and use of mangiferin related products. [Methods]Five steps( material crushing→ ethyl acetate impurity removing → concentrated extract washing → extracting with methanol → crystallization and precipitation) were used.The single factor experiment and L9( 34) orthogonal experiment was carried out to optimize the process parameters including extraction time,ultrasonic power,extraction times,and extraction temperature.[Results] The optimum process of ethyl acetate impurity removal method for extracting and isolating mangiferin from mango leaves was as follows: the mango leaves were crushed and sieved; 3 m L/g of ethyl acetate was added,sealed and soaked for 4 h,ultrasonically shaken for 20 min( 50℃,350 W),filtered at room temperature,filtered with 100 mesh sieve,and extracted three times; added 100% methanol to the residue at 3 m L/g,extract by ultrasonic vibration for 20 min( 350 W,55℃)for four times,filtered with 100 mesh sieve when it was still hot; mixed the extract of each time,condensed by vacuum decompression to get the extract; added 100% methanol at 4 m L/g,mixed and washed for 5 min at room temperature,placed for 10 min,filtered with 100 mesh sieve,washed 3 times repeatedly,and dried the filter residue at 60℃ to obtain the crude mangiferin; added 100% methanol at 4 m L/g,mixed and washed at 50℃ for 5 min,placed at 6℃ for 8 h,dried the filter residue at 60℃,and repeatedly crystallized two times. According to the above process,crude and pure mangiferin products could be obtained,the purity of mangiferin of the crude product was higher than 64. 00%,the total recovery rate was 83. 90%,and the purity of mangiferin of the pure product was higher than 98. 00%,and the total recovery rate was about 66. 40%. [Conclusions] The optimized ethyl acetate impurity removal method is easy in operation,low in cost,and high in efficiency for extracting and isolating mangiferin,and can be applied for actual production of mangiferin.
文摘The tube inside and outside heat transfer mechanism of Passive Residual Heat Removal Heat Exchanger (PRHR HX) was analyzed. The calculation method of this special heat exchanger under natural convection condition in In-containment Refueling Water Storage Tank (IRWST) was carried out. The single-tube coupling model three-dimensional natural circulation in the IRWST was simulated numerically using Fluent. The heat transfer and flow characteristics of the fluid in IRWST were obtained. The comparison of the results between theoretical arithmetic and numerical simulation showed that the theoretical calculation method is suitable for the heat transfer calculation of PRHR HX.
基金Supported by National High Technology Research and Development Program of China(863 Program)(No.2012AA061804-03)
文摘Trapezoidal pulse shaping algorithm is widely applied to improve signal-to-noise ratio(SNR), throughput and energy resolution with the properties of noise suppression, pile-up pulse separation and ballistic deficit correction. The algorithm can be acquired by z transform method which is easier for derivation. However, the baseline drift of trapezoidal pulse appears because the noise superimposes on the input signal. In this paper,two new methods based on convergence analysis and noise suppression are proposed to remove the baseline drift resulting from trapezoidal pulse shaping. Simulations and experimental tests are carried out to verify the methods. The results demonstrate that the proposed methods can remove baseline drift in trapezoidal pulse shaping.
基金supported by the National Natural Science Foundation of China(Nos.61403146 and 61603105)the Fundamental Research Funds for the Central Universities(No.2015ZM128)the Science and Technology Program of Guangzhou in China(Nos.201707010054 and 201704030072)
文摘Compressed sensing(CS) has achieved great success in single noise removal. However, it cannot restore the images contaminated with mixed noise efficiently. This paper introduces nonlocal similarity and cosparsity inspired by compressed sensing to overcome the difficulties in mixed noise removal, in which nonlocal similarity explores the signal sparsity from similar patches, and cosparsity assumes that the signal is sparse after a possibly redundant transform. Meanwhile, an adaptive scheme is designed to keep the balance between mixed noise removal and detail preservation based on local variance. Finally, IRLSM and RACoSaMP are adopted to solve the objective function. Experimental results demonstrate that the proposed method is superior to conventional CS methods, like K-SVD and state-of-art method nonlocally centralized sparse representation(NCSR), in terms of both visual results and quantitative measures.
基金Supported by the National Natural Science Foundation of China(No.51575014,51505012)Natural Science Foundation of Beijing(No.3154029,KZ201410005010)+2 种基金National Defense Scientific Research Project(No.JCKY2014204B003)Project funded by China Postdoctoral Science Foundation(No.2016M591033)Beijing Postdoctoral Research Foundation(No.2015ZZ-13)
文摘Thin-walled parts have low stiffness characteristic. Initial residual stress of thin-walled blanks is an important influence factor on machining stability. The present work is to verify the feasibility of an initial residual stress measurement of layer removal method. According to initial residual stress experiment for casting ZL205 A aluminum alloy tapered thin-walled blank by a common method,namely hole-drilling method,three finite element models with initial residual stress are established to simulate the layer removal method in ABAQUS and ANSYS software. By analyzing the results of simulation and experiments,the cutting residual stress inlayer removal process has a significant effect on measurement results. Reducing cutting residual stress is helpful to improve accuracy of layer removal method.
文摘A conventional complex variable boundary integral equation （CVBIE） in plane elasticity is provided. After using the Somigliana identity between a particular fundamental stress field and a physical stress field, an additional integral equality is obtained. By adding both sides of this integral equality to both sides of the conventional CVBIE, the amended boundary integral equation （BIE） is obtained. The method based on the discretization of the amended BIE is called the amended influence matrix method. With this method, for the Neumann boundary value problem （BVP） of an interior region, a unique solution for the displacement can be obtained. Several numerical examples are provided to prove the efficiency of the suggested method.
文摘Shadow and variable illumination considerably influence the results of image understanding such as image segmentation, object tracking, and object recognition. The intrinsic image decomposition is to separate the reflectance and the illumination image from an observed image. The intrinsic image decomposition is very useful to remove shadows and then improve the performance of image understanding. In this paper, we present a new shadow removal method based on intrinsic image decomposition on a single color image using the Fisher Linear Discriminant (FLD). Under the assumptions-Lambertian surfaces, approximately Planckian lighting, and narrowband camera sensors, there exist an invariant image, which is 1-dimensional greyscale and independent of illuminant color and intensity. The Fisher Linear Discriminant is applied to create the invariant image. And further the shadows can be removed through the difference between invariant image and original color image. The experimental results on real data show good performance of this algorithm.
基金Sponsored by the National Science and Technology Major Project(Grant No.2014ZX04001011)
文摘Residual stress is one of the factors affecting the machining deformation of monolithic structure parts in the aviation industry. Thus, the studies on machining deformation rules induced by residual stresses largely depend on correctly and efficiently measuring the residual stresses of workpieccs. A modified layer-removal method is proposed to measure residual stress by analysing the characteristics of a traditional, layer-removal method. The coefficients of strain release are then deduced according to the simulation results using the finite element method （FEM）. Moreover, the residual stress in a 7075T651 aluminium alloy plate is measured using the proposed method, and the results are then analyzed and compared with the data obtained by the traditional methods. The analysis indicates that the modified layer-removal method is effective and practical for measuring the residual stress distribution in pre-stretched aluminium alloy plates.
文摘According to autopsy reports,patients who died from COVID-19 had a lot of mucus in the lung that obstructed the airways,reduced the effect of mechanical ventilation,and even led to pulmonary failure.Traditional Chinese medicine literature mentions that"Inability to remove phlegm impair s the lung,which leads to death."Hence one of the most urgent problems to be solved is to remove phlegm from the small airways.This article elaborates ten methods to remove phlegm for clinical reference.
文摘According to autopsy reports,patients who died from COVID‑19 had a lot of mucus in the lung that obstructed the airways,reduced the effect of mechanical ventilation,and even led to pulmonary failure.Traditional Chinese medicine literature mentions that“Inability to remove phlegm impairs the lung,which leads to death.”Hence one of the most urgent problems to be solved is to remove phlegm from the small airways.This article elaborates ten methods to remove phlegm for clinical reference.
文摘:This article first analyzes the problems existing in the teaching about diagnosing and removing automobile’s failure,and then discusses some specific teaching strategies on diagnosing and removing automobile’s failure to provide some effective reference for the related staff.
