The incompressible two-phase flows are simulated using combination of an etching multiblock method and a diffuse interface （DI） model, particularly in the com- plex domain that can be decomposed into multiple rectan...The incompressible two-phase flows are simulated using combination of an etching multiblock method and a diffuse interface （DI） model, particularly in the com- plex domain that can be decomposed into multiple rectangular subdomains. The etching multiblock method allows natural communications between the connected subdomains and the efficient parallel computation. The DI model can consider two-phase flows with a large density ratio, and simulate the flows with the moving contact line （MCL） when a geometric formulation of the MCL model is included. Therefore, combination of the etch- ing method and the DI model has potential to deal with a variety of two-phase flows in industrial applications. The performance is examined through a series of numerical exper- iments. The convergence of the etching method is firstly tested by simulating single-phase flows past a square cylinder, and the method for the multiphase flow simulation is vali- dated by investing drops dripping from a pore. The numerical results are compared with either those from other researchers or experimental data. Good agreement is achieved. The method is also used to investigate the impact of a droplet on a grooved substrate and droplet generation in flow focusing devices.展开更多
The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as ...Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as better miscibility between the two components, low crystallinity and better hydrophilicity, which can be modulated by adjusting the block lengths of the two components.展开更多
The self-assembly of the linear rod-coil multiblock copolymers is studied by applying self-consistent-field lattice techniques in a three-dimensional （3D） space. Compared to the copolymer with one rod, the copolymer...The self-assembly of the linear rod-coil multiblock copolymers is studied by applying self-consistent-field lattice techniques in a three-dimensional （3D） space. Compared to the copolymer with one rod, the copolymer with more rods （mrod≥ 2） exhibits rich order-order phase transitions with increasing temperature, where the ordered morphology changes from strips to perforated lamellae and finally to lamellae. In addition, taking the copolymer with mrod = 2 as a representative, we fiarther study the effects of the volume fractions of the rods, the spacer coils and the end coils on the phase behaviors respectively, by which the detailed self-assembled mechanism of the linear rod-coil multiblock copolymers is revealed. Our results are expected to provide guidance for the design of the rod-coil materials.展开更多
In this paper the effects of irradiation on the structures and properties of polysul-fone-polysiloxane multiblock copolymers and its important applied prospects are studied in detail.
A new class of poly(ester-imide-ether) multiblock copolymers was synthesized by transes-terification and melt copolymerization of dimethyl terephthalate (DMT) and N-(4-carbomethoxyphenyl)-4-(carbomethoxy)-phthalimide ...A new class of poly(ester-imide-ether) multiblock copolymers was synthesized by transes-terification and melt copolymerization of dimethyl terephthalate (DMT) and N-(4-carbomethoxyphenyl)-4-(carbomethoxy)-phthalimide with ethylene glycol (EG) and polytetramethylene glycol (PTMG). The structure of the above copolymers was characterized by H-1-NMR and IR spectroscopy. Some properties of the coplymers were also examined. It was found that their mechanical properties and heat stability, compared with poly(ether-ester) copolymers, were obviously improved.展开更多
Near-infrared and mid-infrared spectroscopies were currently used to analyze natural compounds. During the last ten years various multiblocks methods were developed such as Concatenated PLS, Hierarchical-PLS (H-PLS), ...Near-infrared and mid-infrared spectroscopies were currently used to analyze natural compounds. During the last ten years various multiblocks methods were developed such as Concatenated PLS, Hierarchical-PLS (H-PLS), and MultiBlock-PLS (MB-PLS). These three algorithms were used to analyze 55 lavender (Lavandula angustifolia) essential oil samples. The results obtained were compared to the ones obtained respectively in NIR and MIR ranges. The accuracies of the models depend on the spectroscopic technique, pretreatment and the PLS methods. The results showed that the choice of the factor numbers used to build the multiblock models was the most important parameter for the H-PLS and MB-PLS methods.展开更多
For nonlinear hyperbolic problems, conservation of the numerical scheme is important for convergence to the correct weak solutions. In this paper the conservation of the well-known compact scheme up to fourth order of...For nonlinear hyperbolic problems, conservation of the numerical scheme is important for convergence to the correct weak solutions. In this paper the conservation of the well-known compact scheme up to fourth order of accuracy on a single and uniform grid is studied, and a conservative interface treatment is derived for compact schemes on patched grids. For a pure initial value problem, the compact scheme is shown to be equivalent to a scheme in the usual conservative form. For the case of a mixed initial boundary value problem, the compact scheme is conservative only if the rounding errors are small enough. For a patched grid interface, a conservative interface condition useful for mesh refinement and for parallel computation is derived and its order of local accuracy is analyzed.展开更多
Multiblock kernel principal component analysis (MBKPCA) has been proposed to isolate the faults and avoid the high computation cost. However, MBKPCA is not available for dynamic processes. To solve this problem, recur...Multiblock kernel principal component analysis (MBKPCA) has been proposed to isolate the faults and avoid the high computation cost. However, MBKPCA is not available for dynamic processes. To solve this problem, recursive MBKPCA is proposed for monitoring large scale processes. In this paper, we present a new recursive MBKPCA (RMBKPCA) algorithm, where the adaptive technique is adopted for dynamic characteristics. The proposed algorithm reduces the high computation cost, and is suitable for online model updating in the feature space. The proposed algorithm was applied to an industrial process for adaptive monitoring and found to efficiently capture the time-varying and nonlinear relationship in the process variables.展开更多
Janus polymerization consists of anionic and cationic ring opening polymerizations(AROP and CROP)at the two ends of a single propagating polymer chain,followed by a self-triggered chain extension generating multiblock...Janus polymerization consists of anionic and cationic ring opening polymerizations(AROP and CROP)at the two ends of a single propagating polymer chain,followed by a self-triggered chain extension generating multiblock copolymers(MBCPs)in one step.In the contribution,Janus polymerization by Tm(OTf)_(3) or Er(OTf)_(3) catalyst with an epoxy initiator is applied to synthesize MBCPs of semi-crystalline poly(ε-caprolactone)(PCL)blocks from coordinated AROP and poly(1,3-dioxolane-co-ε-caprolactone)(P(DO-co-CL))blocks from CROP of DO with CL.Meanwhile,amorphous random copolymers[P(DO-r-CL)]are synthesized as control by employing other rare earth triflates[RE(OTf)_(3),RE=Y,Nd,Gd and Lu]as catalysts or in the absence of an initiator via CROP.On account of the distinguishable chemical structures and thermal properties between Janus MBCPs and cationic random copolymers,Janus features are confirmed including the CROP and AROP at a single propagating chain.The resultant amphiphilic copolymers self-assemble to nanoparticles in aqueous solution with designable diameters with the corresponding ratios of hydrophilic and hydrophobic seg-ments.MBCPs exhibit good shape memory properties with appropriate deformation temperature close to human body's,providing a prospect on the applications in biomedical devices.展开更多
The primary goal in the analysis of hierarchical distributed monitoring and control architectures is to study the spatiotemporal patterns of the interactions between areas or subsystems.In this paper,a novel conceptua...The primary goal in the analysis of hierarchical distributed monitoring and control architectures is to study the spatiotemporal patterns of the interactions between areas or subsystems.In this paper,a novel conceptual framework for distributed monitoring of power system oscillations using multiblock principal component analysis(MB-PCA)and higher-order singular value decomposition(HOSVD)is proposed to understand,characterize,and visualize the global behavior of the power system.The proposed framework can be used to evaluate the influence of a given area or utility on the oscillatory behavior,uncover low-dimensional structures from high-dimensional data,and analyze the effects of heterogeneous data on the modal characteristics and interpretation of power system.The metrics are then investigated to examine the relationships between the dynamic patterns and participation of individual data blocks in the global behavior of the system.Practical application of these techniques is demonstrated by case studies of two systems:a 14-machine test system and a 5449-bus 635-generator equivalent model of a large power system.展开更多
Environmental problems have attracted much attention in recent years,especially for papermak-ing wastewater discharge.To reduce the loss of effluence discharge violation,quality-related multivariate statistical method...Environmental problems have attracted much attention in recent years,especially for papermak-ing wastewater discharge.To reduce the loss of effluence discharge violation,quality-related multivariate statistical methods have been successfully applied to achieve a robust wastewater treatment system.In this work,a new dynamic multiblock partial least squares(DMBPLS)is pro-posed to extract the time-varying information in a large-scale papermaking wastewater treatment process.By introducing augmented matrices to input and output data,the proposed method not only handles the dynamic characteristic of data and reduces the time delay of fault detection,but enhances the interpretability of model.In addition,the DMBPLS provides a capability of fault location,which has certain guiding significance for fault recovery.In comparison with other mod-els,the DMBPLS has a superior fault detection result.Specifically,the maximum fault detection rate of the DMBPLS is improved by 35.93%and 12.5%for bias and drifting faults,respectively,in comparison with partial least squares(PLS).展开更多
Flows containing steady or nearly steady strong shocks on parts of the flow field,and unsteady turbulence with shocklets on other parts of the flow field are difficult to capture accurately and efficiently employing t...Flows containing steady or nearly steady strong shocks on parts of the flow field,and unsteady turbulence with shocklets on other parts of the flow field are difficult to capture accurately and efficiently employing the same numerical scheme,even under the multiblock grid or adaptive grid refinement framework.While sixthorder or higher-order shock-capturing methods are appropriate for unsteady turbulence with shocklets,third-order or lower shock-capturing methods are more effective for strong steady or nearly steady shocks in terms of convergence.In order to minimize the short comings of low order and high order shock-capturing schemes for the subject flows,a multiblock overlapping grid with different types of spatial schemes and orders of accuracy on different blocks is proposed.The recently developed single block high order filter scheme in generalized geometries for Navier Stokes and magnetohydrodynamics systems is extended to multiblock overlapping grid geometries.The first stage in validating the high order overlapping approach with several test cases is included.展开更多
A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridin...A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridine(DMAP) and dicyclohexylcarbodimide (DCC).The results of the viscometry measurement,GPC and 1H\|NMR,elucidated that multiblock PLE copolymers with high content of short PEG segments( M n=2000) had been successfully obtained.The crystallinity of the copolymers was investigated by X\|ray diffraction.Mechanical testing showed that multiblock copolymers had relatively high tensile strength and large elongation.In a word,the measurements showed that the multiblock PLE copolymers had high content of short PEG segments( M n=2000),high molecular weight( M w～100,000),excellent hydrophilicity and mechanical properties.The results of cells cultured on the multiblock PLE copolymer indicated that it might be suitable to be utilized as cell scaffold for tissue engineering.展开更多
基金Project supported by the National Natural Science Foundation of China(No.11425210)the Fundamental Research Funds for the Central Universities(No.WK2090050025)
文摘The incompressible two-phase flows are simulated using combination of an etching multiblock method and a diffuse interface （DI） model, particularly in the com- plex domain that can be decomposed into multiple rectangular subdomains. The etching multiblock method allows natural communications between the connected subdomains and the efficient parallel computation. The DI model can consider two-phase flows with a large density ratio, and simulate the flows with the moving contact line （MCL） when a geometric formulation of the MCL model is included. Therefore, combination of the etch- ing method and the DI model has potential to deal with a variety of two-phase flows in industrial applications. The performance is examined through a series of numerical exper- iments. The convergence of the etching method is firstly tested by simulating single-phase flows past a square cylinder, and the method for the multiphase flow simulation is vali- dated by investing drops dripping from a pore. The numerical results are compared with either those from other researchers or experimental data. Good agreement is achieved. The method is also used to investigate the impact of a droplet on a grooved substrate and droplet generation in flow focusing devices.
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
基金The authors are Indebted to the National Basic Science Rescarch and Development Grants(973)(No.1999054306).
文摘Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as better miscibility between the two components, low crystallinity and better hydrophilicity, which can be modulated by adjusting the block lengths of the two components.
基金supported by the National Natural Science Foundation of China (Nos. 20804047, 20774096 and 20734003)Programs and the Fund for Creative Research Groups (No. 50921062)subsidized by the Special Funds for National Basic Research Program of China (Nos. 2009CB930100, 2010CB631100)
文摘The self-assembly of the linear rod-coil multiblock copolymers is studied by applying self-consistent-field lattice techniques in a three-dimensional （3D） space. Compared to the copolymer with one rod, the copolymer with more rods （mrod≥ 2） exhibits rich order-order phase transitions with increasing temperature, where the ordered morphology changes from strips to perforated lamellae and finally to lamellae. In addition, taking the copolymer with mrod = 2 as a representative, we fiarther study the effects of the volume fractions of the rods, the spacer coils and the end coils on the phase behaviors respectively, by which the detailed self-assembled mechanism of the linear rod-coil multiblock copolymers is revealed. Our results are expected to provide guidance for the design of the rod-coil materials.
基金Supported by the National Natural Science Foundation of China Laboratory of Polymer Physics of Academia Sinica of China
文摘In this paper the effects of irradiation on the structures and properties of polysul-fone-polysiloxane multiblock copolymers and its important applied prospects are studied in detail.
基金This work was supported by 863 Programme of China (No. 715-004-0010).
文摘A new class of poly(ester-imide-ether) multiblock copolymers was synthesized by transes-terification and melt copolymerization of dimethyl terephthalate (DMT) and N-(4-carbomethoxyphenyl)-4-(carbomethoxy)-phthalimide with ethylene glycol (EG) and polytetramethylene glycol (PTMG). The structure of the above copolymers was characterized by H-1-NMR and IR spectroscopy. Some properties of the coplymers were also examined. It was found that their mechanical properties and heat stability, compared with poly(ether-ester) copolymers, were obviously improved.
文摘Near-infrared and mid-infrared spectroscopies were currently used to analyze natural compounds. During the last ten years various multiblocks methods were developed such as Concatenated PLS, Hierarchical-PLS (H-PLS), and MultiBlock-PLS (MB-PLS). These three algorithms were used to analyze 55 lavender (Lavandula angustifolia) essential oil samples. The results obtained were compared to the ones obtained respectively in NIR and MIR ranges. The accuracies of the models depend on the spectroscopic technique, pretreatment and the PLS methods. The results showed that the choice of the factor numbers used to build the multiblock models was the most important parameter for the H-PLS and MB-PLS methods.
基金This work was supported by Chinese NSF(Contract No.10025210).Running head:Conservation of Compact Schemes.
文摘For nonlinear hyperbolic problems, conservation of the numerical scheme is important for convergence to the correct weak solutions. In this paper the conservation of the well-known compact scheme up to fourth order of accuracy on a single and uniform grid is studied, and a conservative interface treatment is derived for compact schemes on patched grids. For a pure initial value problem, the compact scheme is shown to be equivalent to a scheme in the usual conservative form. For the case of a mixed initial boundary value problem, the compact scheme is conservative only if the rounding errors are small enough. For a patched grid interface, a conservative interface condition useful for mesh refinement and for parallel computation is derived and its order of local accuracy is analyzed.
基金Project supported by the National Basic Research Program (973) of China (No. 2009CB320600) the National Natural Science Foun-dation of China (No. 60974057)
文摘Multiblock kernel principal component analysis (MBKPCA) has been proposed to isolate the faults and avoid the high computation cost. However, MBKPCA is not available for dynamic processes. To solve this problem, recursive MBKPCA is proposed for monitoring large scale processes. In this paper, we present a new recursive MBKPCA (RMBKPCA) algorithm, where the adaptive technique is adopted for dynamic characteristics. The proposed algorithm reduces the high computation cost, and is suitable for online model updating in the feature space. The proposed algorithm was applied to an industrial process for adaptive monitoring and found to efficiently capture the time-varying and nonlinear relationship in the process variables.
基金supported by the National Natural Science Foundationof China(No.21871232)。
文摘Janus polymerization consists of anionic and cationic ring opening polymerizations(AROP and CROP)at the two ends of a single propagating polymer chain,followed by a self-triggered chain extension generating multiblock copolymers(MBCPs)in one step.In the contribution,Janus polymerization by Tm(OTf)_(3) or Er(OTf)_(3) catalyst with an epoxy initiator is applied to synthesize MBCPs of semi-crystalline poly(ε-caprolactone)(PCL)blocks from coordinated AROP and poly(1,3-dioxolane-co-ε-caprolactone)(P(DO-co-CL))blocks from CROP of DO with CL.Meanwhile,amorphous random copolymers[P(DO-r-CL)]are synthesized as control by employing other rare earth triflates[RE(OTf)_(3),RE=Y,Nd,Gd and Lu]as catalysts or in the absence of an initiator via CROP.On account of the distinguishable chemical structures and thermal properties between Janus MBCPs and cationic random copolymers,Janus features are confirmed including the CROP and AROP at a single propagating chain.The resultant amphiphilic copolymers self-assemble to nanoparticles in aqueous solution with designable diameters with the corresponding ratios of hydrophilic and hydrophobic seg-ments.MBCPs exhibit good shape memory properties with appropriate deformation temperature close to human body's,providing a prospect on the applications in biomedical devices.
文摘The primary goal in the analysis of hierarchical distributed monitoring and control architectures is to study the spatiotemporal patterns of the interactions between areas or subsystems.In this paper,a novel conceptual framework for distributed monitoring of power system oscillations using multiblock principal component analysis(MB-PCA)and higher-order singular value decomposition(HOSVD)is proposed to understand,characterize,and visualize the global behavior of the power system.The proposed framework can be used to evaluate the influence of a given area or utility on the oscillatory behavior,uncover low-dimensional structures from high-dimensional data,and analyze the effects of heterogeneous data on the modal characteristics and interpretation of power system.The metrics are then investigated to examine the relationships between the dynamic patterns and participation of individual data blocks in the global behavior of the system.Practical application of these techniques is demonstrated by case studies of two systems:a 14-machine test system and a 5449-bus 635-generator equivalent model of a large power system.
基金supported by Student’s Platform for Innovation and Entrepreneurship Training Program in Jiangsu Province(no.202010298029Z)Guangdong Provincial Natural Science Foundation(no.2016A030306033).
文摘Environmental problems have attracted much attention in recent years,especially for papermak-ing wastewater discharge.To reduce the loss of effluence discharge violation,quality-related multivariate statistical methods have been successfully applied to achieve a robust wastewater treatment system.In this work,a new dynamic multiblock partial least squares(DMBPLS)is pro-posed to extract the time-varying information in a large-scale papermaking wastewater treatment process.By introducing augmented matrices to input and output data,the proposed method not only handles the dynamic characteristic of data and reduces the time delay of fault detection,but enhances the interpretability of model.In addition,the DMBPLS provides a capability of fault location,which has certain guiding significance for fault recovery.In comparison with other mod-els,the DMBPLS has a superior fault detection result.Specifically,the maximum fault detection rate of the DMBPLS is improved by 35.93%and 12.5%for bias and drifting faults,respectively,in comparison with partial least squares(PLS).
基金This work performed under the auspices of the U.S.Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344。
文摘Flows containing steady or nearly steady strong shocks on parts of the flow field,and unsteady turbulence with shocklets on other parts of the flow field are difficult to capture accurately and efficiently employing the same numerical scheme,even under the multiblock grid or adaptive grid refinement framework.While sixthorder or higher-order shock-capturing methods are appropriate for unsteady turbulence with shocklets,third-order or lower shock-capturing methods are more effective for strong steady or nearly steady shocks in terms of convergence.In order to minimize the short comings of low order and high order shock-capturing schemes for the subject flows,a multiblock overlapping grid with different types of spatial schemes and orders of accuracy on different blocks is proposed.The recently developed single block high order filter scheme in generalized geometries for Navier Stokes and magnetohydrodynamics systems is extended to multiblock overlapping grid geometries.The first stage in validating the high order overlapping approach with several test cases is included.
文摘A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridine(DMAP) and dicyclohexylcarbodimide (DCC).The results of the viscometry measurement,GPC and 1H\|NMR,elucidated that multiblock PLE copolymers with high content of short PEG segments( M n=2000) had been successfully obtained.The crystallinity of the copolymers was investigated by X\|ray diffraction.Mechanical testing showed that multiblock copolymers had relatively high tensile strength and large elongation.In a word,the measurements showed that the multiblock PLE copolymers had high content of short PEG segments( M n=2000),high molecular weight( M w～100,000),excellent hydrophilicity and mechanical properties.The results of cells cultured on the multiblock PLE copolymer indicated that it might be suitable to be utilized as cell scaffold for tissue engineering.
