The 2-dimensional equivalent model used in helicopter ground resonance analysis is convenient for its simplicity and clarity. The equivalent body mass, the stiffness and the damping are derived from the modal charaCte...The 2-dimensional equivalent model used in helicopter ground resonance analysis is convenient for its simplicity and clarity. The equivalent body mass, the stiffness and the damping are derived from the modal charaCteristics. In this paper, a 3-dimensional space model is constructed to analyse the ground resonance.There is little difference between the calculated results of the 2-dimensional equivalent model and those of the 3-dimensional space model. Hence, the 2-dimensional model is verified for the practical application. Generally, the linear lead-lag damping of the equivalent rotor blade at the modal frequency is derived from the lead-lag damper characteristics by a procedure of iteration. The transformation of the imaginary part of the complex modulus of the viscoelastic damper into a linear velocity damping is complicated in analysis. A method to use the complex modulus directly in the ground resonance analysis is derived and verified.展开更多
Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transform...Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation (DLT) and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.展开更多
Researching on the impact different steganographic software tools have audio statistical features, revealed the phe- nomenon that when messages are embedded in a WAV file by using a certain tool, the variation of stat...Researching on the impact different steganographic software tools have audio statistical features, revealed the phe- nomenon that when messages are embedded in a WAV file by using a certain tool, the variation of statistical features in the WAV file which already contains messages embedded by the same tool is abruptly smaller than those in which messages have not been embedded. We call it “negative resonance phenomenon” temporarily. With the phenomenon above and Support Vector Machines (SVMs), we can detect the existence of hidden messages, and also identify the tools used to hide them. As shown by the experi- mental results, the proposed method can be very effectively used to detect hidden messages embedded by Hide4PGP, Stegowav and S-Tools4.展开更多
The correlation between Si content (0.1%-0.5%, mass fraction) and pulse laser welding performance of AI-Mn-Mg aluminum alloy sheets was studied. The sheets were fabricated in the laboratory, with gauge of 0.45 mm, H...The correlation between Si content (0.1%-0.5%, mass fraction) and pulse laser welding performance of AI-Mn-Mg aluminum alloy sheets was studied. The sheets were fabricated in the laboratory, with gauge of 0.45 mm, H16 temper by pulse laser welding. It was found that no cracking existed in the welding pool as Si content was below 0.34%. However, when the Si content increased to 0.47%, cracking formed in the welding pool. Microstructure observations indicated that residual eutectic phases distributed at the grain boundaries were discontinuous and appeared to be small particles in lower Si content alloys; the residual eutectic phases distributed at the grain boundaries were partially continuous and appeared to be films in higher Si content alloys. These phenomena could explain why Si content adversely affected the laser welding performance.展开更多
We present a scheme in which the N-atom W state is teleported by employing the selective interactionof a cavity field with a driven three-level atom in the A configuration and detecting a single atom in one of the gro...We present a scheme in which the N-atom W state is teleported by employing the selective interactionof a cavity field with a driven three-level atom in the A configuration and detecting a single atom in one of the groundstates.The long-lived W state is teleported from atom A to atom B when the atoms B and A are sent through acavity successively and atom A is then detected.The advantage is that the present one does not involve the Bell-statemeasurement and is robust against the atomic spontaneous emission.展开更多
In a recent letter [H.F. Wang, X. Ji, and S. Zhang, Phys. Lett. A 358 (2006) 11], an improvement of the multiparty quantum secret splitting and quantum state sharing protocol [F.G. Deng, et al., Phys. Lett. A 354 (...In a recent letter [H.F. Wang, X. Ji, and S. Zhang, Phys. Lett. A 358 (2006) 11], an improvement of the multiparty quantum secret splitting and quantum state sharing protocol [F.G. Deng, et al., Phys. Lett. A 354 (2006) 190.] was presented. We study the security of the improved protocol and find that two or more dishonest participants may recover the secret from the dealer. Hence we further modify the improved protocol, which make it stand against this kind of attack.展开更多
This paper focuses on studying a conformal invariance and a Noether symmetry, a Lie symmetry for a Birkhoffian system in event space. The definitions of the conformal invariance of the system are given. By investigati...This paper focuses on studying a conformal invariance and a Noether symmetry, a Lie symmetry for a Birkhoffian system in event space. The definitions of the conformal invariance of the system are given. By investigation on the relations between the conformal invariance and the Noether symmetry, the conformal invariance and the Lie symmetry, the expressions of conformal factors of the system under these circumstances are obtained. The Noether conserved quantities and the Hojman conserved quantities directly derived from the conformal invariance are given. Two examples are given to illustrate the application of the results.展开更多
In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is desc...In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.展开更多
The density,viscosity and refractive index of aqueous solutions of tetrabutylammonium hydroxide(TBAOH),piperazine(PZ) and their aqueous blends are determined at several temperatures(303.15 to 333.15 K).All these measu...The density,viscosity and refractive index of aqueous solutions of tetrabutylammonium hydroxide(TBAOH),piperazine(PZ) and their aqueous blends are determined at several temperatures(303.15 to 333.15 K).All these measured physicochemical properties decreases with an increase in temperature.The density data is used to calculate the coefficient of thermal expansion and excess molar volume of all aqueous binary and ternary solutions.The coefficient of thermal expansion increases with increase in temperatures and concentrations.The negativity of excess molar volume for all the aqueous solution decreased with increase in temperature.Each physical property is correlated with temperature by least square method and the corresponding coefficients for each property are presented.The prediction values from correlations for the physical properties are in good agreement with the experimental values.展开更多
We find that in a Kerr nonlinear optical resonator, the photon system possesses a new kind of quasiparticle, the nonpolariton. The existence of nonpolaritons should be testified by observing the energy density depende...We find that in a Kerr nonlinear optical resonator, the photon system possesses a new kind of quasiparticle, the nonpolariton. The existence of nonpolaritons should be testified by observing the energy density dependence of the velocity and squeezing of nonpolaritons. As we have investigated, the transition energy density of a Kerr nonlinear optical resonator is larger than that of a normal state.展开更多
In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil ...In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil samples. The preheating temperature had a great influence on the viscosity of oil samples and the resolution of spectral analysis. The repeatability of spectral measurements was impacted by the metal and wax content of the oil samples. For the case of high wax content oils, the wax species began to crystallize in the course of determination that could affect the repeatability of spectral measurements. These factors have evidenced why the preheating devices and filter unit are necessary when low field NMR system is used in the online analysis process. The investigation is very important for the on-line application of the low field NMR.展开更多
Agility metrics are difficult to define in general, mainly due to the multidimensionality and vagueness of the concept of agility itself. In this paper, a knowledge-based framework is utilized for the measurement and ...Agility metrics are difficult to define in general, mainly due to the multidimensionality and vagueness of the concept of agility itself. In this paper, a knowledge-based framework is utilized for the measurement and assessment of public sector's agility by A. T. Kearney model. In this research, the authors used Z2 test in SPSS software. So, the authors discovered that the General Office of Standards & Industrial Research of Sistan & Baluchestan Province in Iran is agile. Finally, the authors determine the weakness points of organization by Friedman test.展开更多
Conformal invariance and a new type of conserved quantities of mechanical systems with variable mass in phase space are studied. Firstly, the definition and determining equation of conformal invariance are presented. ...Conformal invariance and a new type of conserved quantities of mechanical systems with variable mass in phase space are studied. Firstly, the definition and determining equation of conformal invariance are presented. The relationship between the conformal invariance and the Lie symmetry is given, and the necessary and sufficient condition that the conformal invarianee would be the Lie symmetry under the infinitesimal transformations is provided. Secondly, a new type of conserved quantities of the conformal invariance are obtained by using the Lie symmetry of the system. Lastly, an example is given to illustrate the application of the results.展开更多
In this paper,we study conformal vector fields on a Randers manifold with certain curvature properties.In particular,we completely determine conformal vector fields on a Randers manifold of weakly isotropic flag curva...In this paper,we study conformal vector fields on a Randers manifold with certain curvature properties.In particular,we completely determine conformal vector fields on a Randers manifold of weakly isotropic flag curvature.展开更多
The factors influencing dormancy release in lily bulbs strongly affect commercialization success, but the mechanism of dormancy release is still unclear. Magnetic resonance imaging (MRI) can detect changes in morpholo...The factors influencing dormancy release in lily bulbs strongly affect commercialization success, but the mechanism of dormancy release is still unclear. Magnetic resonance imaging (MRI) can detect changes in morphology and water status in a living plant bulb and aid in investigating release factors. To evaluate whether MRI could be used to detect intra-bulb metabolic changes during the dormant period in Oriental Lilies (Lilium 'Sorbonne'), a series of MRI and sugar concentration measurements were performed weekly on bulbs stored for 11 weeks at 4°C. The image quality of intra-bulb structure obtained using T 1-weighted imaging was superior to that obtained using T 2 -weighted imaging and had a higher signal-to-noise ratio (0.97±0.01). Magnetization transfer ratio values for the bud and basal plate declined during the first eight weeks of cold storage (P>0.05), and were well correlated with concentration of soluble sugar in the bud (R 2 =0.95) and basal plate (R 2 =0.93). Thus, MRI can serve as a valuable tool for observation and analysis of dynamic morphological and metabolic changes in vivo during dormancy release. This information is potentially useful as a guide in the improvement of horticultural product quality.展开更多
Rendezvous in circular or near circular orbits has been investigated in great detail, while rendezvous in arbitrary eccentricity elliptical orbits is not sufficiently explored. Among the various optimization methods p...Rendezvous in circular or near circular orbits has been investigated in great detail, while rendezvous in arbitrary eccentricity elliptical orbits is not sufficiently explored. Among the various optimization methods proposed for fuel optimal orbital rendezvous, Lawden's primer vector theory is favored by many researchers with its clear physical concept and simplicity in solu- tion. Prussing has applied the primer vector optimization theory to minimum-fuel, multiple-impulse, time-fixed orbital ren- dezvous in a near circular orbit and achieved great success. Extending Prussing's work, this paper will employ the primer vec- tor theory to study trajectory optimization problems of arbitrary eccentricity elliptical orbit rendezvous. Based on linearized equations of relative motion on elliptical reference orbit (referred to as T-H equations), the primer vector theory is used to deal with time-fixed multiple-impulse optimal rendezvous between two coplanar, coaxial elliptical orbits with arbitrary large ec- centricity. A parameter adjustment method is developed for the prime vector to satisfy the Lawden's necessary condition for the optimal solution. Finally, the optimal multiple-impulse rendezvous solution including the time, direction and magnitudes of the impulse is obtained by solving the two-point boundary value problem. The rendezvous error of the linearized equation is also analyzed. The simulation results confirmed the analyzed results that the rendezvous error is small for the small eccentric- ity case and is large for the higher eccentricity. For better rendezvous accuracy of high eccentricity orbits, a combined method of multiplier penalty function with the simplex search method is used for local optimization. The simplex search method is sensitive to the initial values of optimization variables, but the simulation results show that initial values with the primer vector theory, and the local optimization algorithm can improve the rendezvous accuracy effectively with fast convergence, because the optimal results obtained by the primer vector theory are already very close to the actual optimal solution.展开更多
We study a model of scalars which includes both the SM Higgs and a scalar singlet as composites of heavy vector-like fermions. The vector-like fermions are bounded by the super-strong four-fermion interactions. The sc...We study a model of scalars which includes both the SM Higgs and a scalar singlet as composites of heavy vector-like fermions. The vector-like fermions are bounded by the super-strong four-fermion interactions. The scalar singlet decays to SM vector bosons through loop of heavy vector-like fermions. We show that the surprisingly large production cross section of di-photon events at 750 GeV resonance and the odd decay properties can all be explained.This model serves as a good model for both SM Higgs and a scalar resonance at 750 GeV.展开更多
The composite films of GaSb nanoparticles embedded in SiO2 matrices were fabricated by radio-frequency magnetron co-sputtering. Transmission electron microscope and X-ray diffraction pattern indicate that the GaSb nan...The composite films of GaSb nanoparticles embedded in SiO2 matrices were fabricated by radio-frequency magnetron co-sputtering. Transmission electron microscope and X-ray diffraction pattern indicate that the GaSb nanoparticles were uniformly dispersed in SiO2 matrices. Room temperature transmission spectra exhibit a blue shift of about 2.73 eV. The blue shift increases with decreasing size of GaSb nanoparticles, suggesting the existence of quantum size effects. Room temperature Raman spectra show that there is a larger Raman peak red shift and broadening of the composite films than that of bulk GaSb. This phenomenon is explained by photon confinement effect and tensile stress effect.展开更多
文摘The 2-dimensional equivalent model used in helicopter ground resonance analysis is convenient for its simplicity and clarity. The equivalent body mass, the stiffness and the damping are derived from the modal charaCteristics. In this paper, a 3-dimensional space model is constructed to analyse the ground resonance.There is little difference between the calculated results of the 2-dimensional equivalent model and those of the 3-dimensional space model. Hence, the 2-dimensional model is verified for the practical application. Generally, the linear lead-lag damping of the equivalent rotor blade at the modal frequency is derived from the lead-lag damper characteristics by a procedure of iteration. The transformation of the imaginary part of the complex modulus of the viscoelastic damper into a linear velocity damping is complicated in analysis. A method to use the complex modulus directly in the ground resonance analysis is derived and verified.
基金Project 2005A030 supported by the Youth Science and Research Foundation from China University of Mining & Technology
文摘Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation (DLT) and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.
基金Project (No. 60272031) supported by the National Natural ScienceFoundation of China
文摘Researching on the impact different steganographic software tools have audio statistical features, revealed the phe- nomenon that when messages are embedded in a WAV file by using a certain tool, the variation of statistical features in the WAV file which already contains messages embedded by the same tool is abruptly smaller than those in which messages have not been embedded. We call it “negative resonance phenomenon” temporarily. With the phenomenon above and Support Vector Machines (SVMs), we can detect the existence of hidden messages, and also identify the tools used to hide them. As shown by the experi- mental results, the proposed method can be very effectively used to detect hidden messages embedded by Hide4PGP, Stegowav and S-Tools4.
基金Project(2011KJZD04)supported by the CHINALCO Science and Development Foundation,China
文摘The correlation between Si content (0.1%-0.5%, mass fraction) and pulse laser welding performance of AI-Mn-Mg aluminum alloy sheets was studied. The sheets were fabricated in the laboratory, with gauge of 0.45 mm, H16 temper by pulse laser welding. It was found that no cracking existed in the welding pool as Si content was below 0.34%. However, when the Si content increased to 0.47%, cracking formed in the welding pool. Microstructure observations indicated that residual eutectic phases distributed at the grain boundaries were discontinuous and appeared to be small particles in lower Si content alloys; the residual eutectic phases distributed at the grain boundaries were partially continuous and appeared to be films in higher Si content alloys. These phenomena could explain why Si content adversely affected the laser welding performance.
基金Supported by the Natural Science Foundation of Jiangxi,China under Grant No.2008GQW0017the Scientific Research Foundation of Jiangxi Provincial Department of Education under Grant No.GJJ09504the Foundation of Talent of Jinggang of Jiangxi Province under Grant No.2008DQ00400
文摘We present a scheme in which the N-atom W state is teleported by employing the selective interactionof a cavity field with a driven three-level atom in the A configuration and detecting a single atom in one of the groundstates.The long-lived W state is teleported from atom A to atom B when the atoms B and A are sent through acavity successively and atom A is then detected.The advantage is that the present one does not involve the Bell-statemeasurement and is robust against the atomic spontaneous emission.
基金Supported by National Natural Science Foundation of China under Grant No.60903152National Laboratory for Modern Communications Science Foundation of China under Grant No.9140C1101010601+3 种基金the Beijing Natural Science Foundation under Grant No.4072020a Key Project of Fujian Provincial Universities - Information Technology Research Based on Mathematics the Fujian Province Natural Science Foundation under Grant No.2008J0013the Foundation of Fujian Education Bureau under Grant No.JA08044
文摘In a recent letter [H.F. Wang, X. Ji, and S. Zhang, Phys. Lett. A 358 (2006) 11], an improvement of the multiparty quantum secret splitting and quantum state sharing protocol [F.G. Deng, et al., Phys. Lett. A 354 (2006) 190.] was presented. We study the security of the improved protocol and find that two or more dishonest participants may recover the secret from the dealer. Hence we further modify the improved protocol, which make it stand against this kind of attack.
基金Supported by National Natural Science Foundation of China under Grant No. 10972151the Natural Science Foundation of Higher Education Institution of Jiangsu Province under Grant No. 08KJB130002
文摘This paper focuses on studying a conformal invariance and a Noether symmetry, a Lie symmetry for a Birkhoffian system in event space. The definitions of the conformal invariance of the system are given. By investigation on the relations between the conformal invariance and the Noether symmetry, the conformal invariance and the Lie symmetry, the expressions of conformal factors of the system under these circumstances are obtained. The Noether conserved quantities and the Hojman conserved quantities directly derived from the conformal invariance are given. Two examples are given to illustrate the application of the results.
基金National Natural Science Foundation of China(No.90923027No.51175405)
文摘In this paper,we firstly review the carbon layered surface prepared with electron cyclotron resonance (ECR) plasma sputtering. Secondly,the friction behavior of carbon layered surface under pin-on-disk testing is described. Furthermore,the contact stress evolution processes of layered surface with and without transfer layer during wear are given for understanding the contact mechanisms. Finally,a three-dimension (3D) local yield map of layered surface is introduced,which is useful to predict the possible contact mechanisms.
基金the CO2 Management (MOR) research group of Universiti TeknologiPETRONAS for providing the financial support and facilities
文摘The density,viscosity and refractive index of aqueous solutions of tetrabutylammonium hydroxide(TBAOH),piperazine(PZ) and their aqueous blends are determined at several temperatures(303.15 to 333.15 K).All these measured physicochemical properties decreases with an increase in temperature.The density data is used to calculate the coefficient of thermal expansion and excess molar volume of all aqueous binary and ternary solutions.The coefficient of thermal expansion increases with increase in temperatures and concentrations.The negativity of excess molar volume for all the aqueous solution decreased with increase in temperature.Each physical property is correlated with temperature by least square method and the corresponding coefficients for each property are presented.The prediction values from correlations for the physical properties are in good agreement with the experimental values.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 19847004 and 10474025
文摘We find that in a Kerr nonlinear optical resonator, the photon system possesses a new kind of quasiparticle, the nonpolariton. The existence of nonpolaritons should be testified by observing the energy density dependence of the velocity and squeezing of nonpolaritons. As we have investigated, the transition energy density of a Kerr nonlinear optical resonator is larger than that of a normal state.
基金the financial support from the SINOPEC (ST 13028)
文摘In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil samples. The preheating temperature had a great influence on the viscosity of oil samples and the resolution of spectral analysis. The repeatability of spectral measurements was impacted by the metal and wax content of the oil samples. For the case of high wax content oils, the wax species began to crystallize in the course of determination that could affect the repeatability of spectral measurements. These factors have evidenced why the preheating devices and filter unit are necessary when low field NMR system is used in the online analysis process. The investigation is very important for the on-line application of the low field NMR.
文摘Agility metrics are difficult to define in general, mainly due to the multidimensionality and vagueness of the concept of agility itself. In this paper, a knowledge-based framework is utilized for the measurement and assessment of public sector's agility by A. T. Kearney model. In this research, the authors used Z2 test in SPSS software. So, the authors discovered that the General Office of Standards & Industrial Research of Sistan & Baluchestan Province in Iran is agile. Finally, the authors determine the weakness points of organization by Friedman test.
基金Supported by the Graduate Students' Innovative Foundation of China University of Petrolem (East China) under Grant No.S2009-19
文摘Conformal invariance and a new type of conserved quantities of mechanical systems with variable mass in phase space are studied. Firstly, the definition and determining equation of conformal invariance are presented. The relationship between the conformal invariance and the Lie symmetry is given, and the necessary and sufficient condition that the conformal invarianee would be the Lie symmetry under the infinitesimal transformations is provided. Secondly, a new type of conserved quantities of the conformal invariance are obtained by using the Lie symmetry of the system. Lastly, an example is given to illustrate the application of the results.
基金supported by National Science Foundation of USA (Grant No. DMS-0810159)National Natural Science Foundation of China (Grant No. 11171297)Natural Science Foundationof Zhejiang Province (Grant No. Y6110027)
文摘In this paper,we study conformal vector fields on a Randers manifold with certain curvature properties.In particular,we completely determine conformal vector fields on a Randers manifold of weakly isotropic flag curvature.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest (Grant No. 200903020)
文摘The factors influencing dormancy release in lily bulbs strongly affect commercialization success, but the mechanism of dormancy release is still unclear. Magnetic resonance imaging (MRI) can detect changes in morphology and water status in a living plant bulb and aid in investigating release factors. To evaluate whether MRI could be used to detect intra-bulb metabolic changes during the dormant period in Oriental Lilies (Lilium 'Sorbonne'), a series of MRI and sugar concentration measurements were performed weekly on bulbs stored for 11 weeks at 4°C. The image quality of intra-bulb structure obtained using T 1-weighted imaging was superior to that obtained using T 2 -weighted imaging and had a higher signal-to-noise ratio (0.97±0.01). Magnetization transfer ratio values for the bud and basal plate declined during the first eight weeks of cold storage (P>0.05), and were well correlated with concentration of soluble sugar in the bud (R 2 =0.95) and basal plate (R 2 =0.93). Thus, MRI can serve as a valuable tool for observation and analysis of dynamic morphological and metabolic changes in vivo during dormancy release. This information is potentially useful as a guide in the improvement of horticultural product quality.
基金supported by the National Natural Science Foundation of China(Grant Nos. 10832004 and 11072122)
文摘Rendezvous in circular or near circular orbits has been investigated in great detail, while rendezvous in arbitrary eccentricity elliptical orbits is not sufficiently explored. Among the various optimization methods proposed for fuel optimal orbital rendezvous, Lawden's primer vector theory is favored by many researchers with its clear physical concept and simplicity in solu- tion. Prussing has applied the primer vector optimization theory to minimum-fuel, multiple-impulse, time-fixed orbital ren- dezvous in a near circular orbit and achieved great success. Extending Prussing's work, this paper will employ the primer vec- tor theory to study trajectory optimization problems of arbitrary eccentricity elliptical orbit rendezvous. Based on linearized equations of relative motion on elliptical reference orbit (referred to as T-H equations), the primer vector theory is used to deal with time-fixed multiple-impulse optimal rendezvous between two coplanar, coaxial elliptical orbits with arbitrary large ec- centricity. A parameter adjustment method is developed for the prime vector to satisfy the Lawden's necessary condition for the optimal solution. Finally, the optimal multiple-impulse rendezvous solution including the time, direction and magnitudes of the impulse is obtained by solving the two-point boundary value problem. The rendezvous error of the linearized equation is also analyzed. The simulation results confirmed the analyzed results that the rendezvous error is small for the small eccentric- ity case and is large for the higher eccentricity. For better rendezvous accuracy of high eccentricity orbits, a combined method of multiplier penalty function with the simplex search method is used for local optimization. The simplex search method is sensitive to the initial values of optimization variables, but the simulation results show that initial values with the primer vector theory, and the local optimization algorithm can improve the rendezvous accuracy effectively with fast convergence, because the optimal results obtained by the primer vector theory are already very close to the actual optimal solution.
基金Supported by National Natural Science Foundation of China(NSFC) under Grant Nos.11135009,11375065 and 10925522
文摘We study a model of scalars which includes both the SM Higgs and a scalar singlet as composites of heavy vector-like fermions. The vector-like fermions are bounded by the super-strong four-fermion interactions. The scalar singlet decays to SM vector bosons through loop of heavy vector-like fermions. We show that the surprisingly large production cross section of di-photon events at 750 GeV resonance and the odd decay properties can all be explained.This model serves as a good model for both SM Higgs and a scalar resonance at 750 GeV.
基金the Chinese Climbing Program. We would like to thank Profs. Xu Cunyi and Zuo Jian for Raman measurements at the Center of Structure and Element Analysis (USTC) .
文摘The composite films of GaSb nanoparticles embedded in SiO2 matrices were fabricated by radio-frequency magnetron co-sputtering. Transmission electron microscope and X-ray diffraction pattern indicate that the GaSb nanoparticles were uniformly dispersed in SiO2 matrices. Room temperature transmission spectra exhibit a blue shift of about 2.73 eV. The blue shift increases with decreasing size of GaSb nanoparticles, suggesting the existence of quantum size effects. Room temperature Raman spectra show that there is a larger Raman peak red shift and broadening of the composite films than that of bulk GaSb. This phenomenon is explained by photon confinement effect and tensile stress effect.