The focus of green analytical chemistry(GAC)is to minimize the negative impacts of analytical procedures on human safety,human health,and the environment.Several factors,such as the reagents used,sample collection,sam...The focus of green analytical chemistry(GAC)is to minimize the negative impacts of analytical procedures on human safety,human health,and the environment.Several factors,such as the reagents used,sample collection,sample processing,instruments,energy consumed,and the quantities of hazardous materials and waste generated during analytical procedures,need to be considered in the evaluation of the greenness of analytical assays.In this study,we propose a greenness evaluation metric for analytical methods(GEMAM).The new greenness metric is simple,flexible,and comprehensive.The evaluation criteria are based on both the 12 principles of GAC(SIGNIFICANCE)and the 10 factors of sample preparation,and the results are presented on a 0–10 scale.The GEMAM calculation process is easy to perform,and its results are easy to interpret.The output of GEMAM is a pictogram that can provide both qualitative and quantitative information based on color and number.展开更多
This study presents a novel methodology to obtain an approximate analytical solution for an isotropic homo-geneous elastic medium with displacement and traction boundary conditions.The solution is derived through solv...This study presents a novel methodology to obtain an approximate analytical solution for an isotropic homo-geneous elastic medium with displacement and traction boundary conditions.The solution is derived through solving a specific numerical problem under the scope of the linear finite element method(LFEM),so the method is termed computational method for analytical solutions with finite elements(CMAS-FE).The primary objective of the CMAS-FE is to construct analytical expressions for displacements and reaction forces at nodes,as well as for strains and stresses at elemental quadrature points,all of which are formulated as infinite series solutions of various orders of Poisson’s ratios.Like the conventional LFEM,the CMAS-FE forms global sparse linear equations,but the Young’s modulus and Poisson’s ratio remain variables(or symbols).By employing a direct inverse method to solve these symbolic linear systems,an analytical expression of the displacement field can be constructed.The CMAS-FE is validated via patch and bending tests,which demonstrate convergence with mesh and term refine-ment.Furthermore,the CMAS-FE is applied to obtain the bending stiffness of a beam structure and to estimate an approximate stress intensity factor for a straight crack within a square-shaped plate.展开更多
Compared to the conventional permanent magnet synchronous machine(PMSM),the main characteristic of permanent magnet torque machine(PMTM)with high torque is that armature current is high,which has a great influence on ...Compared to the conventional permanent magnet synchronous machine(PMSM),the main characteristic of permanent magnet torque machine(PMTM)with high torque is that armature current is high,which has a great influence on magnetic circuit saturation,so this paper proposes a novel analytical method(AM)considering this problem.The key of this new AM is to consider armature reaction flux and armature leakage flux,which are closely related to output torque.Firstly,the expressions,including magnetomotive force(MMF)generated by permanent magnets(PMs)and armature windings are derived,and meanwhile slotting effect is considered by planning flux path.In addition,the expression of leakage flux density generated by armature windings are calculated,and flux density equivalence coefficient of tooth is calculated to be 2/3,which is used to solve the problem of uneven saturation of each tooth.Then,based on main flux factor and leakage flux factor proposed,an improved iteration process is proposed,and by this new process,the flux density of each yoke and tooth can be obtained,which is beneficial to obtain more accurate air-gap flux density and flux linkage.Finally,a prototype of 60-pole 54-slot is fabricated,and the performances of the electric machine,such as back electromotive force(EMF)and output torque,are calculated by this new AM and finite element method(FEM).The results of FEM and experimental test show that this new AM is good enough to calculate the performance of PMTM.展开更多
Firstly, a new analytical error model of the cumulative geoid height using the three-dimensional diagonal tensors of satellite gravity gradiometry （SGG） is introduced based on the variance-covariance matrix principl...Firstly, a new analytical error model of the cumulative geoid height using the three-dimensional diagonal tensors of satellite gravity gradiometry （SGG） is introduced based on the variance-covariance matrix principle. Secondly, a study for the requirements demonstration on the next-generation GOCE Follow-On satellite gravity gradiometry system is developed using different satellite orbital altitudes and measurement accuracies of satellite gravity gradiometer by the new analytical error model of SGG. The research results show that it is preferable to design satellite orbital altitudes of 300 km–400km and choose the measurement accuracies of 10-13/s2 –10-15/s2 from satellite gravity gradiometer. Finally, the complementarity of the four-stage satellite gravity missions, including past CHAMP, current GRACE, and GOCE, and next-generation GOCE Follow-On, is contrastively demonstrated for precisely recovering the Earth’s full-frequency gravitational field with high spatial resolution.展开更多
A simple and highly accurate semi-analytical method, called the differential transformation method(DTM), was used for solving the nonlinear temperature distribution equation in solid and porous longitudinal fin with t...A simple and highly accurate semi-analytical method, called the differential transformation method(DTM), was used for solving the nonlinear temperature distribution equation in solid and porous longitudinal fin with temperature dependent internal heat generation. The problem was solved for two main cases. In the first case, heat generation was assumed variable by fin temperature for a solid fin and in second heat generation varied with temperature for a porous fin. Results are presented for the temperature distribution for a range of values of parameters appearing in the mathematical formulation(e.g. N, εG, and G). Results reveal that DTM is very effective and convenient. Also, it is found that this method can achieve more suitable results in comparison to numerical methods.展开更多
Magnetic coils for specific requirements are widely used in modern quantum physics. In this study, a general analytical method of designing the shielded coils for generating an arbitrary axial magnetic field is propos...Magnetic coils for specific requirements are widely used in modern quantum physics. In this study, a general analytical method of designing the shielded coils for generating an arbitrary axial magnetic field is proposed. The theoretical formula for an axial magnetic field generated by a single shielded coil is obtained and used to construct specific coils. The structural parameters of these coils are determined by fitting the theoretical formula with their specific requirements. The feasibility of this method is proved by realizing four concrete kinds of coils: uniform magnetic field generating coils, gradient magnetic field generating coils, asymmetrical uniform magnetic field generating coils, and parabolic magnetic field generating coils. The correctness of these theoretical results is demonstrated by both the finite element simulations and the relevant experimental results. Furthermore, the application of this method is of great significance for developing the quantum physics and quantum devices in future.展开更多
According to the differential equation for transverse displacement function of anisotropic rectangular thin plates in free vibration, a general analytical solution is established. This general solution, composed of th...According to the differential equation for transverse displacement function of anisotropic rectangular thin plates in free vibration, a general analytical solution is established. This general solution, composed of the composite solutions of trigonometric function and hyperbolic function, can satisfy the problem of arbitrary boundary conditions along four edges. The algebraic polynomial with double sine series solutions can also satisfy the problem of boundary conditions at four corners. Consequently, this general solution can be used to solve the vibration problem of anisotropic rectangular plates with arbitrary boundaries accurately. The integral constants can be determined by boundary conditions of four edges and four corners. Each natural frequency and vibration mode can be solved by the determinate of coefficient matrix from the homogeneous linear algebraic equations equal to zero. For example, a composite symmetric angle ply laminated plate with four edges clamped has been calculated and discussed.展开更多
The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especi...The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especially in metabolic behavior. As a result, it is of vital importance to separate the enantiomers of a chiral drug in metabolic studies. This paper discusses enantioselective methods （include high-performance liquid chromatography, gas chromatography, capillary electrophoresis and high-performance liquid chromatography-mass spectrometry） that applied in chiral drug metabolism, using most recent examples where possible.展开更多
A new statistical method, the fuzzy analytical method, was introduced in the optimization processes of liposome preparation. It took the full advantage of the information from orthogonal experiments to obtain the opti...A new statistical method, the fuzzy analytical method, was introduced in the optimization processes of liposome preparation. It took the full advantage of the information from orthogonal experiments to obtain the optimal liposome preparation conditions by considering all the evaluation indexes. Liposomes were made by the modified reverse-phase evaporation method and the properties of liposomes including size, encapsulation efficiency and physical stability were selected as the evaluation indexes to indicate the quality of liposomes. The experimental data of these properties were analyzed by three different methods including direct observation, variance analysis and fuzzy analytical method. The optimal preparation conditions obtained from these methods were validated with further experiments. The results of all possible combinations of levels for all factors in orthogonal experiments were acquired by the fuzzy analytical method. All evaluation indexes were taken into account and the optimal preparation condition was obtained. The optimal preparation conditions from direct observation and fuzzy analytical method were different and further validation studies indicated that the optimal conditions obtained from the fuzzy analytical method were in agreement with that from traditional statistical analysis. Fuzzy analytical method avoided the problem resulted from the traditional method, in which different levels of the same factor were obtained when considering different evaluation indexes. More information could be obtained from the fuzzy analytical method and the blind area within the experimental range was eliminated. As a result, fuzzy analytical method can be applied in the optimization processes of liposome preparation.展开更多
In the present work, the different sample collection, pretreatment and analytical methods for polycyclic aromatic hydrocarbons （PAHs） in airborne particulates is systematacially reviewed, and the applications of the...In the present work, the different sample collection, pretreatment and analytical methods for polycyclic aromatic hydrocarbons （PAHs） in airborne particulates is systematacially reviewed, and the applications of these pretreatment and analytical methods for PAHs are compared in detail. Some comments on the future expectation are also presented.展开更多
In order to improve rolled strip quality, precise plate shape control theory should be established. Roll flat- tening theory is an important part of the plate shape theory. To improve the accuracy of roll flattening c...In order to improve rolled strip quality, precise plate shape control theory should be established. Roll flat- tening theory is an important part of the plate shape theory. To improve the accuracy of roll flattening calculation based on semi infinite body model, especially near the two roll barrel edges, a new and more accurate roll flattening model is proposed. Based on boundary integral equation method, an analytical model for solving a finite length semi infinite body is established. The lateral surface displacement field of the finite length semi-infinite body is simulated by finite element method （FEM） and lateral surface displacement decay functions are established. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distribu ted force is obtained and an accurate roll flattening model is established. Different from the traditional semi-infinite body model, the matrix form of the new roll flattening model is established through the mathematical derivation. The result from the new model is more consistent with that by FEM especially near the edges.展开更多
A differential equation of first order can be expressed by the equation of motion of a mechanical system. In this paper, three methods of analytical mechanics, i.e. the Hamilton-Noether method, the Lagrange-Noether me...A differential equation of first order can be expressed by the equation of motion of a mechanical system. In this paper, three methods of analytical mechanics, i.e. the Hamilton-Noether method, the Lagrange-Noether method and the Poisson method, are given to solve a differential equation of first order, of which the way may be called the mechanical methodology in mathematics.展开更多
Nanoliposomes are considered to be the most successful nanoparticle drug delivery system, but their fate in vivo has not been fully understood due to lack of reliable bioanalytical methods, which seriously limits the ...Nanoliposomes are considered to be the most successful nanoparticle drug delivery system, but their fate in vivo has not been fully understood due to lack of reliable bioanalytical methods, which seriously limits the development of liposomal drugs. Hence, an overview of currently used bioanalytical methods is imperative to lay the groundwork for the need of developing a bioanalytical method for liposome measurements in vivo. Currently, major analytical methods for nanoliposomes measurement in vivo include fluorescence labeling, radiolabeling, magnetic resonance imaging（MRI）, mass spectrometry and computed tomography. In this review, these bioanalytical methods are summarized, and the advantages and disadvantages of each are discussed. We provide insights into the applicability and limitations of these analytical methods in the application of nanoliposomes measurement in vivo, and highlight the recent development of instrumental analysis techniques. The review is devoted to providing a comprehensive overview of the investigation of nanoliposomes design and associated fate in vivo, promoting the development of bioanalytical techniques for nanoliposomes measurement, and understanding the pharmacokinetic behavior, effectiveness and potential toxicity of nanoliposomes in vivo.展开更多
An impedance analytical method （IAM） is developed to study the interaction of plane water wave with a slotted-wall caisson breakwater. The non-linear boundary condition at the slotted-wall is expressed in terms of f...An impedance analytical method （IAM） is developed to study the interaction of plane water wave with a slotted-wall caisson breakwater. The non-linear boundary condition at the slotted-wall is expressed in terms of flow resistance. A set of algebraic expressions are obtained for free surface elevation inside and outside chamber, and reflection coefficient. The prediction of the reflection coefficients shows that the relative widths of the chamber inducing the minimum reflection coefficient for a slotted-wall caisson breakwater are in a range of 0.10～0.20, which are smaller than that （0.15～0.25） for a perforated-wall caisson breakwater. The reflection coefficients and free surface elevation obtained by the present model are compared with that of laboratory experiments carried out by previous researchers.展开更多
Terbinafine is a new powerful antifungal agent indicated for both oral and topical treatment of myco- sessince. It is highly effective in the treatment of determatomycoses. The chemical and pharmaceutical analysis of ...Terbinafine is a new powerful antifungal agent indicated for both oral and topical treatment of myco- sessince. It is highly effective in the treatment of determatomycoses. The chemical and pharmaceutical analysis of the drug requires effective analytical methods for quality control and pharmacodynamic and pharmacokinetic studies. Ever since it was introduced as an effective antifungal agent, many methods have been developed and validated for its assay in pharmaceuticals and biological materials. This article reviews the various methods reported during the last 25 years.展开更多
Assessment of acid sulfate soil risk is an important step for acid sulfate soil management and its reliability depends very much on the suitability and accuracy of various analytical methods for estimating sulfide-der...Assessment of acid sulfate soil risk is an important step for acid sulfate soil management and its reliability depends very much on the suitability and accuracy of various analytical methods for estimating sulfide-derived potential acidity, actual acidity and acid-neutralizing capacity in acid sulfate soils. This paper critically reviews various analytical methods that are currently used for determination of the above parameters, as well as their implications for environmental risk assessment of acid sulfate soi1s.展开更多
Pioglitazone is an oral anti-hyperglycemic agent. It is used for the treatment of diabetes mellitus type 2. It selectively stimulates nuclear receptor peroxisome proliferator-activated receptor gamma （PPAR-gamma）. I...Pioglitazone is an oral anti-hyperglycemic agent. It is used for the treatment of diabetes mellitus type 2. It selectively stimulates nuclear receptor peroxisome proliferator-activated receptor gamma （PPAR-gamma）. It was the tenth-best-selling drug in the U.S. in 2008. This article examines published analytical methods reported so far in the literature for the determination of pioglitazone in biological samples and pharmaceutical formulations. They include various techniques like electrochemical methods, spectrophotometry, capillary electrophoresis, high-performance liquid chromatography, liquid chromatography-electrospray ionization-tandem mass spectrometry and high-performance thin layer chromatography.展开更多
Objective:To evaluate relationship betweenα-cypermethrin residues in Interceptor~? nets by using HPTLC methods and mortality percentage in standard WHO’s method 'cone test' after repeated washings.Methods:In...Objective:To evaluate relationship betweenα-cypermethrin residues in Interceptor~? nets by using HPTLC methods and mortality percentage in standard WHO’s method 'cone test' after repeated washings.Methods:Interceptor~? containingα-cypermethrin was provided by BASF Company.The washing procedure and bioassay tests were carried out according to the WHO-recommended methods.Malaria vector,An.stephensi was exposed to impregnated bed net for three minutes and then mortality measured after 24 hour recovery period.Chemical analysis was carried out in chemical laboratory by using high performance thin layer chromatography method.Results:Result of cone bioassay method showed that washing reduced the efficacy of Interceptor~? bed net from 100%in unwashed nets to 15%at 20 washes.After 20 washes,nets contain(61.2±2.8) mg/m^2 resulting 15%mortality in cone test.Killing activity was reduced when nets were washed.Conclusions:Results will provide an essential clue for monitoring and evaluation of bioefficacy of any long lasting impregnated bed net for quality control.Findings of this study will be useful for WHO.local investigators and people who wish to use pyrethroid-impregnated bed nets for malaria vector control.展开更多
Based on the characteristics of an L-shaped column composed of concrete-filled square steel tubes, the axial compression experiment and nonlinear finite element analysis were carried out to study the mechanical proper...Based on the characteristics of an L-shaped column composed of concrete-filled square steel tubes, the axial compression experiment and nonlinear finite element analysis were carried out to study the mechanical property of the L-shaped column. The load-displacement curve for the L-shaped column, the deflection and load-strain curves for the mono columns were obtained by the axial compression experiment. The results show that the L-shaped column exhibits a flexural-torsional buckling failure mode. The numerical simulation by the finite element analysis shows that the bearing capacity and failure mode are in accordance with those of the axial compression experiment and the feasi- bility of the finite element analysis is proved. For the calculation of the bearing capacity of the L-shaped column com- posed of concrete-filled square steel tubes, an analytical method is proposed based on the theory of the elastic stability and spatial truss model. The results of the analytical method are in good agreement with those of the axial compression experiment and the finite element analysis.展开更多
An analytical model for straight hemming was developed based on minimum energy method to study the effect of flanging die corner radius on hemming qualities.In order to calculate plastic strain and strain energy more ...An analytical model for straight hemming was developed based on minimum energy method to study the effect of flanging die corner radius on hemming qualities.In order to calculate plastic strain and strain energy more exactly,the neutral layer of specimen corner after hemming is assumed to be a half ellipse with its major semi-axis unknown.Isotropic hardening rule is adopted to describe bending and reverse bending processes neglecting Bauschinger effect.The model takes into account the material property parameters in order to satisfy a wide application range of different materials.Specimen profile,creepage/growing(roll-in/roll-out) and maximum equivalent strain are predicted,which are greatly influenced by the flanging die corner radius.Experimental facilities were designed and hemming experiments were undertaken.The predicted results of the present analytical model were compared to experimental data as well as finite element(FE) simulation results.It was confirmed that they are in good agreement,and the model can be used to evaluate whether the material used as an outer panel for hemming is appropriate and to optimize process parameters when the material used for hemming is changed.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.:81603182 and 81703607)the Fundamental Research Funds for the Central Universities,China(Grant Nos.:DUT21RC(3)057,DUT23YG226,DUT24MS018,and DUT23YG228)+1 种基金the Natural Science Foundation of Liaoning Province,China(Grant No.:2023-MSBA-018)the Open Funding of Cancer Hospital of Dalian University of Technology,China(Grant No.:2024-ZLKF-33).
文摘The focus of green analytical chemistry(GAC)is to minimize the negative impacts of analytical procedures on human safety,human health,and the environment.Several factors,such as the reagents used,sample collection,sample processing,instruments,energy consumed,and the quantities of hazardous materials and waste generated during analytical procedures,need to be considered in the evaluation of the greenness of analytical assays.In this study,we propose a greenness evaluation metric for analytical methods(GEMAM).The new greenness metric is simple,flexible,and comprehensive.The evaluation criteria are based on both the 12 principles of GAC(SIGNIFICANCE)and the 10 factors of sample preparation,and the results are presented on a 0–10 scale.The GEMAM calculation process is easy to perform,and its results are easy to interpret.The output of GEMAM is a pictogram that can provide both qualitative and quantitative information based on color and number.
基金supported by the National Natural Science Foundation of China Excellence Research Group Program for“Multiscale Problems in Nonlinear Mechanics”(Grant No.12588201)the National Key R&D Program of China(Grant No.2023YFA1008901)+1 种基金the National Nat-ural Science Foundation of China(Grant No.12172009)supported by“The Fundamental Research Funds for the Central Universities,Peking University”.
文摘This study presents a novel methodology to obtain an approximate analytical solution for an isotropic homo-geneous elastic medium with displacement and traction boundary conditions.The solution is derived through solving a specific numerical problem under the scope of the linear finite element method(LFEM),so the method is termed computational method for analytical solutions with finite elements(CMAS-FE).The primary objective of the CMAS-FE is to construct analytical expressions for displacements and reaction forces at nodes,as well as for strains and stresses at elemental quadrature points,all of which are formulated as infinite series solutions of various orders of Poisson’s ratios.Like the conventional LFEM,the CMAS-FE forms global sparse linear equations,but the Young’s modulus and Poisson’s ratio remain variables(or symbols).By employing a direct inverse method to solve these symbolic linear systems,an analytical expression of the displacement field can be constructed.The CMAS-FE is validated via patch and bending tests,which demonstrate convergence with mesh and term refine-ment.Furthermore,the CMAS-FE is applied to obtain the bending stiffness of a beam structure and to estimate an approximate stress intensity factor for a straight crack within a square-shaped plate.
基金supported in part by the National Natural Science Foundation of China under Grant 52125701.
文摘Compared to the conventional permanent magnet synchronous machine(PMSM),the main characteristic of permanent magnet torque machine(PMTM)with high torque is that armature current is high,which has a great influence on magnetic circuit saturation,so this paper proposes a novel analytical method(AM)considering this problem.The key of this new AM is to consider armature reaction flux and armature leakage flux,which are closely related to output torque.Firstly,the expressions,including magnetomotive force(MMF)generated by permanent magnets(PMs)and armature windings are derived,and meanwhile slotting effect is considered by planning flux path.In addition,the expression of leakage flux density generated by armature windings are calculated,and flux density equivalence coefficient of tooth is calculated to be 2/3,which is used to solve the problem of uneven saturation of each tooth.Then,based on main flux factor and leakage flux factor proposed,an improved iteration process is proposed,and by this new process,the flux density of each yoke and tooth can be obtained,which is beneficial to obtain more accurate air-gap flux density and flux linkage.Finally,a prototype of 60-pole 54-slot is fabricated,and the performances of the electric machine,such as back electromotive force(EMF)and output torque,are calculated by this new AM and finite element method(FEM).The results of FEM and experimental test show that this new AM is good enough to calculate the performance of PMTM.
基金Project supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences for Distinguished Young Scholar (Grant No. KZCX2-EW-QN114)the National Natural Science Foundation of China for Young Scholar (Grant Nos. 41004006, 41131067, 11173049, and 41202094)+5 种基金the Merit-based Scientific Research Foundation of the State Ministry of Human Resources and Social Security of China for Returned Overseas Chinese Scholars(Grant No. 2011)the Open Research Fund Program of the Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences (Grant No. 2011-04)the Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, China (Grant No. 11-01-02)the Open Research Fund Program of the Key Laboratory of Geo-Informatics of National Administration of Surveying, Mapping and Geoinformation of China(Grant No. 201322)the Open Fund of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Grant No. PLN1113)the Foundation of State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing (Grant No. PRP/open-1206)
文摘Firstly, a new analytical error model of the cumulative geoid height using the three-dimensional diagonal tensors of satellite gravity gradiometry （SGG） is introduced based on the variance-covariance matrix principle. Secondly, a study for the requirements demonstration on the next-generation GOCE Follow-On satellite gravity gradiometry system is developed using different satellite orbital altitudes and measurement accuracies of satellite gravity gradiometer by the new analytical error model of SGG. The research results show that it is preferable to design satellite orbital altitudes of 300 km–400km and choose the measurement accuracies of 10-13/s2 –10-15/s2 from satellite gravity gradiometer. Finally, the complementarity of the four-stage satellite gravity missions, including past CHAMP, current GRACE, and GOCE, and next-generation GOCE Follow-On, is contrastively demonstrated for precisely recovering the Earth’s full-frequency gravitational field with high spatial resolution.
文摘A simple and highly accurate semi-analytical method, called the differential transformation method(DTM), was used for solving the nonlinear temperature distribution equation in solid and porous longitudinal fin with temperature dependent internal heat generation. The problem was solved for two main cases. In the first case, heat generation was assumed variable by fin temperature for a solid fin and in second heat generation varied with temperature for a porous fin. Results are presented for the temperature distribution for a range of values of parameters appearing in the mathematical formulation(e.g. N, εG, and G). Results reveal that DTM is very effective and convenient. Also, it is found that this method can achieve more suitable results in comparison to numerical methods.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61701515 and 61671458)the Postdoctoral Science Foundation,China(Grant No.2017M613367)+1 种基金the Natural Science Foundation of Hunan Province,China(Grant No.2018JJ3608)the Research Project of National University of Defense Technology,China(Grant No.ZK170204)
文摘Magnetic coils for specific requirements are widely used in modern quantum physics. In this study, a general analytical method of designing the shielded coils for generating an arbitrary axial magnetic field is proposed. The theoretical formula for an axial magnetic field generated by a single shielded coil is obtained and used to construct specific coils. The structural parameters of these coils are determined by fitting the theoretical formula with their specific requirements. The feasibility of this method is proved by realizing four concrete kinds of coils: uniform magnetic field generating coils, gradient magnetic field generating coils, asymmetrical uniform magnetic field generating coils, and parabolic magnetic field generating coils. The correctness of these theoretical results is demonstrated by both the finite element simulations and the relevant experimental results. Furthermore, the application of this method is of great significance for developing the quantum physics and quantum devices in future.
基金Project supported by the National Natural Science Foundation of China (No.19872076)
文摘According to the differential equation for transverse displacement function of anisotropic rectangular thin plates in free vibration, a general analytical solution is established. This general solution, composed of the composite solutions of trigonometric function and hyperbolic function, can satisfy the problem of arbitrary boundary conditions along four edges. The algebraic polynomial with double sine series solutions can also satisfy the problem of boundary conditions at four corners. Consequently, this general solution can be used to solve the vibration problem of anisotropic rectangular plates with arbitrary boundaries accurately. The integral constants can be determined by boundary conditions of four edges and four corners. Each natural frequency and vibration mode can be solved by the determinate of coefficient matrix from the homogeneous linear algebraic equations equal to zero. For example, a composite symmetric angle ply laminated plate with four edges clamped has been calculated and discussed.
基金National Natural Science Foundation of China(Grant No.30225047 and 30701038)
文摘The chiral nature of biological systems enables their stereoselective interaction with chiral compounds. It has been well documented that the enantiomers ofa chiral drug may show differences in drug disposition especially in metabolic behavior. As a result, it is of vital importance to separate the enantiomers of a chiral drug in metabolic studies. This paper discusses enantioselective methods （include high-performance liquid chromatography, gas chromatography, capillary electrophoresis and high-performance liquid chromatography-mass spectrometry） that applied in chiral drug metabolism, using most recent examples where possible.
文摘A new statistical method, the fuzzy analytical method, was introduced in the optimization processes of liposome preparation. It took the full advantage of the information from orthogonal experiments to obtain the optimal liposome preparation conditions by considering all the evaluation indexes. Liposomes were made by the modified reverse-phase evaporation method and the properties of liposomes including size, encapsulation efficiency and physical stability were selected as the evaluation indexes to indicate the quality of liposomes. The experimental data of these properties were analyzed by three different methods including direct observation, variance analysis and fuzzy analytical method. The optimal preparation conditions obtained from these methods were validated with further experiments. The results of all possible combinations of levels for all factors in orthogonal experiments were acquired by the fuzzy analytical method. All evaluation indexes were taken into account and the optimal preparation condition was obtained. The optimal preparation conditions from direct observation and fuzzy analytical method were different and further validation studies indicated that the optimal conditions obtained from the fuzzy analytical method were in agreement with that from traditional statistical analysis. Fuzzy analytical method avoided the problem resulted from the traditional method, in which different levels of the same factor were obtained when considering different evaluation indexes. More information could be obtained from the fuzzy analytical method and the blind area within the experimental range was eliminated. As a result, fuzzy analytical method can be applied in the optimization processes of liposome preparation.
基金Project supported by the National Natural Science Foundation of China (No. 20437020 20575073) NSFC-JSPS Joint Research Project (No. 20511140134) the Major Research Program of Chinese Academy of Sciences (KZCX3-SW-432)
文摘In the present work, the different sample collection, pretreatment and analytical methods for polycyclic aromatic hydrocarbons （PAHs） in airborne particulates is systematacially reviewed, and the applications of these pretreatment and analytical methods for PAHs are compared in detail. Some comments on the future expectation are also presented.
基金Item Sponsored by National Natural Science Foundation of China(51075353)
文摘In order to improve rolled strip quality, precise plate shape control theory should be established. Roll flat- tening theory is an important part of the plate shape theory. To improve the accuracy of roll flattening calculation based on semi infinite body model, especially near the two roll barrel edges, a new and more accurate roll flattening model is proposed. Based on boundary integral equation method, an analytical model for solving a finite length semi infinite body is established. The lateral surface displacement field of the finite length semi-infinite body is simulated by finite element method （FEM） and lateral surface displacement decay functions are established. Based on the boundary integral equation method, the numerical solution of the finite length semi-infinite body under the distribu ted force is obtained and an accurate roll flattening model is established. Different from the traditional semi-infinite body model, the matrix form of the new roll flattening model is established through the mathematical derivation. The result from the new model is more consistent with that by FEM especially near the edges.
基金Project supported by the National Natural Science Foundation of China （Grant No 10272021） and the Doctorate Foundation of the State Education Ministry of China （Grant No 20040007022）.
文摘A differential equation of first order can be expressed by the equation of motion of a mechanical system. In this paper, three methods of analytical mechanics, i.e. the Hamilton-Noether method, the Lagrange-Noether method and the Poisson method, are given to solve a differential equation of first order, of which the way may be called the mechanical methodology in mathematics.
基金supported by the National Natural Science Foundation of China (Grant No. 81430087, 81673396, 81603182)
文摘Nanoliposomes are considered to be the most successful nanoparticle drug delivery system, but their fate in vivo has not been fully understood due to lack of reliable bioanalytical methods, which seriously limits the development of liposomal drugs. Hence, an overview of currently used bioanalytical methods is imperative to lay the groundwork for the need of developing a bioanalytical method for liposome measurements in vivo. Currently, major analytical methods for nanoliposomes measurement in vivo include fluorescence labeling, radiolabeling, magnetic resonance imaging（MRI）, mass spectrometry and computed tomography. In this review, these bioanalytical methods are summarized, and the advantages and disadvantages of each are discussed. We provide insights into the applicability and limitations of these analytical methods in the application of nanoliposomes measurement in vivo, and highlight the recent development of instrumental analysis techniques. The review is devoted to providing a comprehensive overview of the investigation of nanoliposomes design and associated fate in vivo, promoting the development of bioanalytical techniques for nanoliposomes measurement, and understanding the pharmacokinetic behavior, effectiveness and potential toxicity of nanoliposomes in vivo.
文摘An impedance analytical method （IAM） is developed to study the interaction of plane water wave with a slotted-wall caisson breakwater. The non-linear boundary condition at the slotted-wall is expressed in terms of flow resistance. A set of algebraic expressions are obtained for free surface elevation inside and outside chamber, and reflection coefficient. The prediction of the reflection coefficients shows that the relative widths of the chamber inducing the minimum reflection coefficient for a slotted-wall caisson breakwater are in a range of 0.10～0.20, which are smaller than that （0.15～0.25） for a perforated-wall caisson breakwater. The reflection coefficients and free surface elevation obtained by the present model are compared with that of laboratory experiments carried out by previous researchers.
文摘Terbinafine is a new powerful antifungal agent indicated for both oral and topical treatment of myco- sessince. It is highly effective in the treatment of determatomycoses. The chemical and pharmaceutical analysis of the drug requires effective analytical methods for quality control and pharmacodynamic and pharmacokinetic studies. Ever since it was introduced as an effective antifungal agent, many methods have been developed and validated for its assay in pharmaceuticals and biological materials. This article reviews the various methods reported during the last 25 years.
文摘Assessment of acid sulfate soil risk is an important step for acid sulfate soil management and its reliability depends very much on the suitability and accuracy of various analytical methods for estimating sulfide-derived potential acidity, actual acidity and acid-neutralizing capacity in acid sulfate soils. This paper critically reviews various analytical methods that are currently used for determination of the above parameters, as well as their implications for environmental risk assessment of acid sulfate soi1s.
文摘Pioglitazone is an oral anti-hyperglycemic agent. It is used for the treatment of diabetes mellitus type 2. It selectively stimulates nuclear receptor peroxisome proliferator-activated receptor gamma （PPAR-gamma）. It was the tenth-best-selling drug in the U.S. in 2008. This article examines published analytical methods reported so far in the literature for the determination of pioglitazone in biological samples and pharmaceutical formulations. They include various techniques like electrochemical methods, spectrophotometry, capillary electrophoresis, high-performance liquid chromatography, liquid chromatography-electrospray ionization-tandem mass spectrometry and high-performance thin layer chromatography.
基金financially supported by the Tehran University of Medical Sciences
文摘Objective:To evaluate relationship betweenα-cypermethrin residues in Interceptor~? nets by using HPTLC methods and mortality percentage in standard WHO’s method 'cone test' after repeated washings.Methods:Interceptor~? containingα-cypermethrin was provided by BASF Company.The washing procedure and bioassay tests were carried out according to the WHO-recommended methods.Malaria vector,An.stephensi was exposed to impregnated bed net for three minutes and then mortality measured after 24 hour recovery period.Chemical analysis was carried out in chemical laboratory by using high performance thin layer chromatography method.Results:Result of cone bioassay method showed that washing reduced the efficacy of Interceptor~? bed net from 100%in unwashed nets to 15%at 20 washes.After 20 washes,nets contain(61.2±2.8) mg/m^2 resulting 15%mortality in cone test.Killing activity was reduced when nets were washed.Conclusions:Results will provide an essential clue for monitoring and evaluation of bioefficacy of any long lasting impregnated bed net for quality control.Findings of this study will be useful for WHO.local investigators and people who wish to use pyrethroid-impregnated bed nets for malaria vector control.
基金Foundation of Key Laboratory of Coast Civil Structure Safety (Tianjin University),Ministry of EducationChinese Program for New Century Excellent Talents in University+1 种基金Seed Foundation of Tianjin UniversitySeed Foundation of Xinjiang University
文摘Based on the characteristics of an L-shaped column composed of concrete-filled square steel tubes, the axial compression experiment and nonlinear finite element analysis were carried out to study the mechanical property of the L-shaped column. The load-displacement curve for the L-shaped column, the deflection and load-strain curves for the mono columns were obtained by the axial compression experiment. The results show that the L-shaped column exhibits a flexural-torsional buckling failure mode. The numerical simulation by the finite element analysis shows that the bearing capacity and failure mode are in accordance with those of the axial compression experiment and the feasi- bility of the finite element analysis is proved. For the calculation of the bearing capacity of the L-shaped column com- posed of concrete-filled square steel tubes, an analytical method is proposed based on the theory of the elastic stability and spatial truss model. The results of the analytical method are in good agreement with those of the axial compression experiment and the finite element analysis.
基金Project supported by the National Natural Science Foundation for Key Program of China (No. 50835002),the National Natural Science Foundation of China (No. 50975174),the National Natural Science Foundation for Innovative Research Group of China (No. 50821003)
文摘An analytical model for straight hemming was developed based on minimum energy method to study the effect of flanging die corner radius on hemming qualities.In order to calculate plastic strain and strain energy more exactly,the neutral layer of specimen corner after hemming is assumed to be a half ellipse with its major semi-axis unknown.Isotropic hardening rule is adopted to describe bending and reverse bending processes neglecting Bauschinger effect.The model takes into account the material property parameters in order to satisfy a wide application range of different materials.Specimen profile,creepage/growing(roll-in/roll-out) and maximum equivalent strain are predicted,which are greatly influenced by the flanging die corner radius.Experimental facilities were designed and hemming experiments were undertaken.The predicted results of the present analytical model were compared to experimental data as well as finite element(FE) simulation results.It was confirmed that they are in good agreement,and the model can be used to evaluate whether the material used as an outer panel for hemming is appropriate and to optimize process parameters when the material used for hemming is changed.
