Waterlogging is one of the major abiotic stresses threatening crop yields globally.Under waterlogging stress,plants suffer from oxidative stress,heavy metal toxicity and energy deficiency,leading to metabolic disorder...Waterlogging is one of the major abiotic stresses threatening crop yields globally.Under waterlogging stress,plants suffer from oxidative stress,heavy metal toxicity and energy deficiency,leading to metabolic disorders and growth inhibition.On the other hand,plants have evolved waterlogging-tolerance or adaptive mechanisms,including morphological changes,alternation of respiratory pathways,antioxidant protection and endogenous hormonal regulation.In this review,recent advances in studies on the effects of waterlogging stress and the mechanisms of waterlogging tolerance in plants are presented,and the genetic differences in waterlogging tolerance among plant species or genotypes within a species are illustrated.We also summarize the identified QTLs and key genes associated with waterlogging tolerance.展开更多
County-level libraries have an inescapable responsibility for cultivating local cultural identity and realizing rural revitalization.Therefore,we analyzed factors that afect the service fficiency of gass-1oots librari...County-level libraries have an inescapable responsibility for cultivating local cultural identity and realizing rural revitalization.Therefore,we analyzed factors that afect the service fficiency of gass-1oots libraries in Henan Province through a field investigation and qualitative comparative analysis(QCA),and proposed a higlh-efficiency configuration.In addition,we put forward the strategy of improving the quality and efficiency of our country's county-level libraries in the electonic information age.展开更多
The impregnation of a special grade PAN precursor,fibers wus carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical stncture and the mechani...The impregnation of a special grade PAN precursor,fibers wus carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical stncture and the mechanical properties of precursor fibers thermally stabilized and their resulting carbon fibers u'ere characterized by the combiination use of densities, wide-angle X-ray diffraction (WAXD), X-ray photoelectron speetroscopy (XPS), elemental analysis ( EA ), Fourier traasform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM), etc.KMnO4 as a strong oxidizer can swell, oxidize and corrode the skin of a precursor.fiber, and transform C≡N groups to C≡N ones, meamchile , it can decreuse the crystal .size increuse the orientation index and the costallinity index, furthermore it can increuse the densities of modified PAN precursors and resuhing thermally stabilized fibers. As a result, the carbon fibers developed from modified PAN fibers show an improvement in tensile strength of 31.25 % and an improvement in elongation of 77.78 % , but a decrease of 16. 52% in Young's modulus.展开更多
The dropping scales is an important parameter for comber noil and combing quality. Because the rocking of the nipper shaft makes the nippers move backward and forward through a series of links, the original position o...The dropping scales is an important parameter for comber noil and combing quality. Because the rocking of the nipper shaft makes the nippers move backward and forward through a series of links, the original position of nipper frame is altered when changing the dropping scales, the other parameters of combing are changed accordingly. In this paper, the timing of opening-closing on nipper, the timing of cylinder’s combing, the timing of detaching-lapping and variation of nip pressure are calculated and their effects on combing are analyzed in different dropping scales on E7/6 comber.展开更多
Gray cast iron that is used for automobile engine cylinder liners was laser surface hardened using Nd : YAG quasi-continuous and CO2 continuous wave laser, respectively. The macromorphology and microstructure of the ...Gray cast iron that is used for automobile engine cylinder liners was laser surface hardened using Nd : YAG quasi-continuous and CO2 continuous wave laser, respectively. The macromorphology and microstructure of the laser surface hardened layers were investigated using an optical microscope. Geometric dimensions including depth and width and microhardness distribution of the hardened layers were also examined in order to evaluate the quality of the hardened layers.展开更多
Waste reduction is gaining importance as the preferred means of pollution prevention. Reactor network synthesis is one of the key parts of chemical process synthesis. In this study, a geometric approach to reactor net...Waste reduction is gaining importance as the preferred means of pollution prevention. Reactor network synthesis is one of the key parts of chemical process synthesis. In this study, a geometric approach to reactor network synthesis for waste reduction is presented. The bases of the approach are potential environment impact (PEI) rate-law expression, PEI balance and the instantaneous value of environmental indexes. The instantaneous value can be derived using the PEI balance, PEI rate-law expression and the environmental indexes. The optimal reactor networks with the minimum generation of potential environment impact are geometrically derived by comparing with areas of the corresponding regions. From the case study involving complex reactions, the approach does not involve solving the complicated mathematical problem and can avoid the dimension limitation in the attainable region approach.展开更多
The distribution of the light reflected from various fabric surfaces was studied. A series of samples of different fibers, weaves and colors were investigated. The experiments show that the goniophotometric curves of ...The distribution of the light reflected from various fabric surfaces was studied. A series of samples of different fibers, weaves and colors were investigated. The experiments show that the goniophotometric curves of fabrics change with constituent fibers, weave, dyeing and finishing, and experimental condition.The goniophotometric curves for fabrics of same kind with different colors are same in general shape, and the reflectance or the height of the curves are changed to the extent of that they are in proportion with the brightness or the tristimulus value Y of the samples. The goniophotometric curve also varies in form when the incident angle is changed. Discussion and explanation for the above mentioned are given. Luster of the samples was calculated with methods suggested by different indexing systems.展开更多
Different polyacrylonitrile (PAN) precursor fibers that displayed various thermal properties were studied by using differential scanning calorimetry (DSC). Results showed that some commercial PAN precursor fibers ...Different polyacrylonitrile (PAN) precursor fibers that displayed various thermal properties were studied by using differential scanning calorimetry (DSC). Results showed that some commercial PAN precursor fibers displayed double separated peaks and these fibers were of high quality because of their process stability during their conversion to carbon fibers of high performance. Some fabrication processes, such as spinning, drawing, could not apparently change the DSC features of a PAN precursor fiber. It was concluded that the thermal properties of a PAN precursor fiber was mainly determined from its comonomer content type and compositions.展开更多
In this paper, we study the Cauchy problem for the following quasi-linear wave equation utt-2kuxxt=β(ux^n)x, where k〉0 and β are real numbers, and n ≥ 2 is an integer. We prove that for any T〉0, the Cauchy prob...In this paper, we study the Cauchy problem for the following quasi-linear wave equation utt-2kuxxt=β(ux^n)x, where k〉0 and β are real numbers, and n ≥ 2 is an integer. We prove that for any T〉0, the Cauchy problem admits a unique global smooth solution u∈C^∞((0, T]; H^∞(R)) ∩ C([0, T]; H^2(R)) ∩ C^1([0, T]; L^2(R)) under suitable assumptions on the initial data.展开更多
With high effective screen-printing technique, a new triode field emission display (FED)with enhanced petaling cold cathode was fabricated. For enhancing the field emission performance,a series of improved measures wa...With high effective screen-printing technique, a new triode field emission display (FED)with enhanced petaling cold cathode was fabricated. For enhancing the field emission performance,a series of improved measures was adopted in the fabrication course. Seen from the fabrication structure of enhanced petaling cold cathode,the bar conducting electrode and the petaling bottom electrode were fabricated with the sintered silver slurry on cathode glass faceplate. The luminescence image with green phosphor was displayed for the sealed enhanced petaling cold cathode FED. The measured results showed that the enhanced petaling cold cathode had good field emission performance. The enhanced petaling cold cathode FED possessed low turn-on electric-field of 1. 95 V /μm,large emission current of 1 389. 6 μA,and high luminance brightness of 1 520 cd /m2 .展开更多
The tensile properties of a series of soybean protein yarns are tested in USTER THINKPAID Ⅲ. A nonlinear viscoelastic model has been proposed to describe the tensile behavior of soybean protein yarns. The model is co...The tensile properties of a series of soybean protein yarns are tested in USTER THINKPAID Ⅲ. A nonlinear viscoelastic model has been proposed to describe the tensile behavior of soybean protein yarns. The model is composed of a Maxwell element, a linear spring and a nonlinear spring. The tensile properties of soybean protein yam are analyzed. The stress-strain curves of the yams are fitted. The average breaking tenacity and specific work of rupture are calculated using the average breaking strain. Comparisons indicate that theoretical predictions conform the experimental results very well.展开更多
In the qq quark model, the states π(1300), η(1295) and η(1475) are assigned as the 2^1S0 meson nonet. The mass of the isodoublet remains interesting and needs further confirmation in experiments. This paper e...In the qq quark model, the states π(1300), η(1295) and η(1475) are assigned as the 2^1S0 meson nonet. The mass of the isodoublet remains interesting and needs further confirmation in experiments. This paper employs the phenomenological trajectory on the (N, M^2)-plot and meson meson mixing methods to calculate the mass of this state, the calculated results are 1341 MeV and 1311.58 ± 59 MeV respectively. These predictions can be compared with experiments in the future.展开更多
Based on Lyapunov stability theory, a novel adaptive controller is designed for a class of chaotic systems .The parameters identification and synchronization of chaotic systems can be carried out simultaneously. The c...Based on Lyapunov stability theory, a novel adaptive controller is designed for a class of chaotic systems .The parameters identification and synchronization of chaotic systems can be carried out simultaneously. The controller and the updating law of parameters identification are directly constructed by analytic formula. Simulation results with Chen’s system and R?ssler system show the effectiveness of the proposed controller.展开更多
Crystallization behaviors of Ce60Al15Fe5+xCo20-x(x=0,5,10) bulk metallic glasses(BMGs) were studied by means of differential scanning calorimeter(DSC) and X-ray diffraction(XRD).The crystallization processes of differ...Crystallization behaviors of Ce60Al15Fe5+xCo20-x(x=0,5,10) bulk metallic glasses(BMGs) were studied by means of differential scanning calorimeter(DSC) and X-ray diffraction(XRD).The crystallization processes of different samples were simulated by JMA equation.Experimental results demonstrated that incubation and crystallization time increased with decreasing isothermal temperature for the same sample.The crystallization mechanism of CeAlFeCo BMGs was discussed.展开更多
Conducting blends of polyacrylonitrile (PAN) copolymer and dodecylbenzene sulfonic acid doped polyaniline (PANI-DBSA) were prepared by solution blending of the two components. By means of various characterization ...Conducting blends of polyacrylonitrile (PAN) copolymer and dodecylbenzene sulfonic acid doped polyaniline (PANI-DBSA) were prepared by solution blending of the two components. By means of various characterization methods including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and cone-plate rheometry, the effects of PANI-DBSA content on the thermal behavior, morphological and rheological properties of the blends were investigated. A single and composition-dependent /'g was found for each of all blends and the thermal stability of PANI-DBSA/PAN was superior to that of both pure Co-PAN and PANI- DBSA. Rheological results show that the apparent viscosity of blend solution decreased at low PANI- DBSA content (2.5 wt%) while increased at high PANI-DBSA content (7.5wt%-10 wt%). Moreover, the shear-thinning appeared more distinctly with the incorporation of PANI-DBSA into the blend solutions especially at a high shear rate.展开更多
Nd55-x Al10+x Fe15 (x =0, 5, 10) bulk glass-forming alloys with distinct glass transition in differential scanning calorimetry (DSC) traces were obtained by suction casting, The glass forming ability (GFA) of t...Nd55-x Al10+x Fe15 (x =0, 5, 10) bulk glass-forming alloys with distinct glass transition in differential scanning calorimetry (DSC) traces were obtained by suction casting, The glass forming ability (GFA) of the alloys was investigated. It was found that the reduced glass transition temperature (Trg) and the parameter γ of the alloys increased with the increasing concentration of Al. The glass formation enthalpy of the alloys was calculated based on Miedema's model, and it was suggested that the GFA of the alloys could be enhanced by the decrease of the glass formation enthalpy with Al additions.展开更多
In this paper, we consider nonnegative solutions to Cauchy problem for the general nonlinear filtration equations ut -Dj (α^ij (x, t, u)Diψ(u)) +b^i (t, u)Diu+C(x, t, u) = 0, and obtain the existence, un...In this paper, we consider nonnegative solutions to Cauchy problem for the general nonlinear filtration equations ut -Dj (α^ij (x, t, u)Diψ(u)) +b^i (t, u)Diu+C(x, t, u) = 0, and obtain the existence, uniqueness and blow-up in finite time of these solutions under some structure conditions.展开更多
Winding and web transport systems are subjected to quasi-periodic disturbances of the web tension due to the eccentricity and the non-circularity of the reel and rolls. The disturbances induced by the non-circularity ...Winding and web transport systems are subjected to quasi-periodic disturbances of the web tension due to the eccentricity and the non-circularity of the reel and rolls. The disturbances induced by the non-circularity and eccentricity of the rolls are quasi-periodic with a frequency that varies with their rotation speed. An adaptive method of rejection of these disturbances is proposed in this paper. It is based on a phase-locked loop structure that estimates simutaneously the phase and magnitude of the perturbation and then cancels it. This algorithm can be plugged in an existing industrial controller. The stability and robustness of the algorithm are also discussed. The ability of the algorithm to reject quasi-periodic disturbances with slowly varying frequencies is shown through simulation results.展开更多
The robust stabilization problem for uncertain systems with time-varying delay has been discussed. A new sufficient criterion is obtained to guarantee the closed-loop system robust stabilizable. The controller gain ma...The robust stabilization problem for uncertain systems with time-varying delay has been discussed. A new sufficient criterion is obtained to guarantee the closed-loop system robust stabilizable. The controller gain matrix is included in a Hamiltonian matrix. The Hamiltonian matrix can be constructed by the boundedness of the uncertainties. Some examples are given to illustrate the feasibility of the criterion.展开更多
The integral-differential equations for three-dimensional planar interfacial cracks of arbitrary shape in transversely isotropic bimaterials were derived by virtue of the Somigliana identity and the fundamental soluti...The integral-differential equations for three-dimensional planar interfacial cracks of arbitrary shape in transversely isotropic bimaterials were derived by virtue of the Somigliana identity and the fundamental solutions, in which the displacement discontinuities across the crack faces are the unknowns to be determined. The interface is parallel to both the planes of isotropy. The singular behaviors of displacement and stress near the crack border were analyzed and the stress singularity indexes were obtained by integral equation method. The stress intensity factors were expressed in terms of the displacement discontinuities. In the non-oscillatory case, the hyper-singular boundary integral-differential equations were reduced to hyper-singular boundary integral equations similar to those of homogeneously isotropic materials.展开更多
基金supported by the Key Research Projects of Zhejiang Province,China(2021C02064-3 and 2021C02057)the China Agriculture Research System(CARS-05)the Jiangsu Collaborative Innovation Center for Modern Crop Production,China(JCIC-MCP).
文摘Waterlogging is one of the major abiotic stresses threatening crop yields globally.Under waterlogging stress,plants suffer from oxidative stress,heavy metal toxicity and energy deficiency,leading to metabolic disorders and growth inhibition.On the other hand,plants have evolved waterlogging-tolerance or adaptive mechanisms,including morphological changes,alternation of respiratory pathways,antioxidant protection and endogenous hormonal regulation.In this review,recent advances in studies on the effects of waterlogging stress and the mechanisms of waterlogging tolerance in plants are presented,and the genetic differences in waterlogging tolerance among plant species or genotypes within a species are illustrated.We also summarize the identified QTLs and key genes associated with waterlogging tolerance.
文摘County-level libraries have an inescapable responsibility for cultivating local cultural identity and realizing rural revitalization.Therefore,we analyzed factors that afect the service fficiency of gass-1oots libraries in Henan Province through a field investigation and qualitative comparative analysis(QCA),and proposed a higlh-efficiency configuration.In addition,we put forward the strategy of improving the quality and efficiency of our country's county-level libraries in the electonic information age.
基金Founded by the National Natural Science Foundation of China(No.50333070)
文摘The impregnation of a special grade PAN precursor,fibers wus carried out in a 8 wt% KMnO4 aqueous solution to obtain modified PAN precursor fibers. The effects of modification on the chemical stncture and the mechanical properties of precursor fibers thermally stabilized and their resulting carbon fibers u'ere characterized by the combiination use of densities, wide-angle X-ray diffraction (WAXD), X-ray photoelectron speetroscopy (XPS), elemental analysis ( EA ), Fourier traasform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM), etc.KMnO4 as a strong oxidizer can swell, oxidize and corrode the skin of a precursor.fiber, and transform C≡N groups to C≡N ones, meamchile , it can decreuse the crystal .size increuse the orientation index and the costallinity index, furthermore it can increuse the densities of modified PAN precursors and resuhing thermally stabilized fibers. As a result, the carbon fibers developed from modified PAN fibers show an improvement in tensile strength of 31.25 % and an improvement in elongation of 77.78 % , but a decrease of 16. 52% in Young's modulus.
文摘The dropping scales is an important parameter for comber noil and combing quality. Because the rocking of the nipper shaft makes the nippers move backward and forward through a series of links, the original position of nipper frame is altered when changing the dropping scales, the other parameters of combing are changed accordingly. In this paper, the timing of opening-closing on nipper, the timing of cylinder’s combing, the timing of detaching-lapping and variation of nip pressure are calculated and their effects on combing are analyzed in different dropping scales on E7/6 comber.
文摘Gray cast iron that is used for automobile engine cylinder liners was laser surface hardened using Nd : YAG quasi-continuous and CO2 continuous wave laser, respectively. The macromorphology and microstructure of the laser surface hardened layers were investigated using an optical microscope. Geometric dimensions including depth and width and microhardness distribution of the hardened layers were also examined in order to evaluate the quality of the hardened layers.
基金the Support Program for the Young Backbones of the College Teachers in Henan Province (No.[2005]461)the Key Technologies R &D Program of Henan Province (No.072102360052)
文摘Waste reduction is gaining importance as the preferred means of pollution prevention. Reactor network synthesis is one of the key parts of chemical process synthesis. In this study, a geometric approach to reactor network synthesis for waste reduction is presented. The bases of the approach are potential environment impact (PEI) rate-law expression, PEI balance and the instantaneous value of environmental indexes. The instantaneous value can be derived using the PEI balance, PEI rate-law expression and the environmental indexes. The optimal reactor networks with the minimum generation of potential environment impact are geometrically derived by comparing with areas of the corresponding regions. From the case study involving complex reactions, the approach does not involve solving the complicated mathematical problem and can avoid the dimension limitation in the attainable region approach.
文摘The distribution of the light reflected from various fabric surfaces was studied. A series of samples of different fibers, weaves and colors were investigated. The experiments show that the goniophotometric curves of fabrics change with constituent fibers, weave, dyeing and finishing, and experimental condition.The goniophotometric curves for fabrics of same kind with different colors are same in general shape, and the reflectance or the height of the curves are changed to the extent of that they are in proportion with the brightness or the tristimulus value Y of the samples. The goniophotometric curve also varies in form when the incident angle is changed. Discussion and explanation for the above mentioned are given. Luster of the samples was calculated with methods suggested by different indexing systems.
基金supported by the National Natural Science Foundation of China under grant No.59783002by the Natural Science Foundation of Henan under grant Nos.200510465008 and 0523021200.
文摘Different polyacrylonitrile (PAN) precursor fibers that displayed various thermal properties were studied by using differential scanning calorimetry (DSC). Results showed that some commercial PAN precursor fibers displayed double separated peaks and these fibers were of high quality because of their process stability during their conversion to carbon fibers of high performance. Some fabrication processes, such as spinning, drawing, could not apparently change the DSC features of a PAN precursor fiber. It was concluded that the thermal properties of a PAN precursor fiber was mainly determined from its comonomer content type and compositions.
基金Supported by the National Natural Science Foundation of China(10371073)
文摘In this paper, we study the Cauchy problem for the following quasi-linear wave equation utt-2kuxxt=β(ux^n)x, where k〉0 and β are real numbers, and n ≥ 2 is an integer. We prove that for any T〉0, the Cauchy problem admits a unique global smooth solution u∈C^∞((0, T]; H^∞(R)) ∩ C([0, T]; H^2(R)) ∩ C^1([0, T]; L^2(R)) under suitable assumptions on the initial data.
基金National Natural Science Foundations of China(No.60976058,No.61274078)Natural Science Research Project of Henan Province Education Department,China(No.2009B510019)
文摘With high effective screen-printing technique, a new triode field emission display (FED)with enhanced petaling cold cathode was fabricated. For enhancing the field emission performance,a series of improved measures was adopted in the fabrication course. Seen from the fabrication structure of enhanced petaling cold cathode,the bar conducting electrode and the petaling bottom electrode were fabricated with the sintered silver slurry on cathode glass faceplate. The luminescence image with green phosphor was displayed for the sealed enhanced petaling cold cathode FED. The measured results showed that the enhanced petaling cold cathode had good field emission performance. The enhanced petaling cold cathode FED possessed low turn-on electric-field of 1. 95 V /μm,large emission current of 1 389. 6 μA,and high luminance brightness of 1 520 cd /m2 .
文摘The tensile properties of a series of soybean protein yarns are tested in USTER THINKPAID Ⅲ. A nonlinear viscoelastic model has been proposed to describe the tensile behavior of soybean protein yarns. The model is composed of a Maxwell element, a linear spring and a nonlinear spring. The tensile properties of soybean protein yam are analyzed. The stress-strain curves of the yams are fitted. The average breaking tenacity and specific work of rupture are calculated using the average breaking strain. Comparisons indicate that theoretical predictions conform the experimental results very well.
文摘In the qq quark model, the states π(1300), η(1295) and η(1475) are assigned as the 2^1S0 meson nonet. The mass of the isodoublet remains interesting and needs further confirmation in experiments. This paper employs the phenomenological trajectory on the (N, M^2)-plot and meson meson mixing methods to calculate the mass of this state, the calculated results are 1341 MeV and 1311.58 ± 59 MeV respectively. These predictions can be compared with experiments in the future.
基金Supported by National Natural Science Foundation of China (No. 60074008, 60274007).
文摘Based on Lyapunov stability theory, a novel adaptive controller is designed for a class of chaotic systems .The parameters identification and synchronization of chaotic systems can be carried out simultaneously. The controller and the updating law of parameters identification are directly constructed by analytic formula. Simulation results with Chen’s system and R?ssler system show the effectiveness of the proposed controller.
基金supported by the Foundation of Science & Technology Department of Henan Province (082102230035)
文摘Crystallization behaviors of Ce60Al15Fe5+xCo20-x(x=0,5,10) bulk metallic glasses(BMGs) were studied by means of differential scanning calorimeter(DSC) and X-ray diffraction(XRD).The crystallization processes of different samples were simulated by JMA equation.Experimental results demonstrated that incubation and crystallization time increased with decreasing isothermal temperature for the same sample.The crystallization mechanism of CeAlFeCo BMGs was discussed.
文摘Conducting blends of polyacrylonitrile (PAN) copolymer and dodecylbenzene sulfonic acid doped polyaniline (PANI-DBSA) were prepared by solution blending of the two components. By means of various characterization methods including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and cone-plate rheometry, the effects of PANI-DBSA content on the thermal behavior, morphological and rheological properties of the blends were investigated. A single and composition-dependent /'g was found for each of all blends and the thermal stability of PANI-DBSA/PAN was superior to that of both pure Co-PAN and PANI- DBSA. Rheological results show that the apparent viscosity of blend solution decreased at low PANI- DBSA content (2.5 wt%) while increased at high PANI-DBSA content (7.5wt%-10 wt%). Moreover, the shear-thinning appeared more distinctly with the incorporation of PANI-DBSA into the blend solutions especially at a high shear rate.
文摘Nd55-x Al10+x Fe15 (x =0, 5, 10) bulk glass-forming alloys with distinct glass transition in differential scanning calorimetry (DSC) traces were obtained by suction casting, The glass forming ability (GFA) of the alloys was investigated. It was found that the reduced glass transition temperature (Trg) and the parameter γ of the alloys increased with the increasing concentration of Al. The glass formation enthalpy of the alloys was calculated based on Miedema's model, and it was suggested that the GFA of the alloys could be enhanced by the decrease of the glass formation enthalpy with Al additions.
基金Foundation item: Supported by National Science Foundation of China(10572156) Supported by Natural Science Foundation of Henan Province(0211010900) Supported by National Science Foundation of Department of Education of Henan Province(200510465001)
文摘In this paper, we consider nonnegative solutions to Cauchy problem for the general nonlinear filtration equations ut -Dj (α^ij (x, t, u)Diψ(u)) +b^i (t, u)Diu+C(x, t, u) = 0, and obtain the existence, uniqueness and blow-up in finite time of these solutions under some structure conditions.
文摘Winding and web transport systems are subjected to quasi-periodic disturbances of the web tension due to the eccentricity and the non-circularity of the reel and rolls. The disturbances induced by the non-circularity and eccentricity of the rolls are quasi-periodic with a frequency that varies with their rotation speed. An adaptive method of rejection of these disturbances is proposed in this paper. It is based on a phase-locked loop structure that estimates simutaneously the phase and magnitude of the perturbation and then cancels it. This algorithm can be plugged in an existing industrial controller. The stability and robustness of the algorithm are also discussed. The ability of the algorithm to reject quasi-periodic disturbances with slowly varying frequencies is shown through simulation results.
基金the National Natural Science Foundation (No.60274007) of China and the Foundation of Young Backbone Teacher of Henan Province.
文摘The robust stabilization problem for uncertain systems with time-varying delay has been discussed. A new sufficient criterion is obtained to guarantee the closed-loop system robust stabilizable. The controller gain matrix is included in a Hamiltonian matrix. The Hamiltonian matrix can be constructed by the boundedness of the uncertainties. Some examples are given to illustrate the feasibility of the criterion.
基金Project supported by the Program for New Century Excellent Talents in University of Henan Province (HANCET)
文摘The integral-differential equations for three-dimensional planar interfacial cracks of arbitrary shape in transversely isotropic bimaterials were derived by virtue of the Somigliana identity and the fundamental solutions, in which the displacement discontinuities across the crack faces are the unknowns to be determined. The interface is parallel to both the planes of isotropy. The singular behaviors of displacement and stress near the crack border were analyzed and the stress singularity indexes were obtained by integral equation method. The stress intensity factors were expressed in terms of the displacement discontinuities. In the non-oscillatory case, the hyper-singular boundary integral-differential equations were reduced to hyper-singular boundary integral equations similar to those of homogeneously isotropic materials.