This paper investigates vibration control of beam through electro-magnetic constrained layer damping （EMCLD） which consists of electromagnet layer, permanent magnet layer and viscoelastic damping layer. When the coi...This paper investigates vibration control of beam through electro-magnetic constrained layer damping （EMCLD） which consists of electromagnet layer, permanent magnet layer and viscoelastic damping layer. When the coil of the electromagnet is electrified with proper control strategy, the electromagnet can exert magnetic force opposite to the direction of structural deformation so that the structural vibration is attenuated. A mathematical model is developed based on the equivalent current method to calculate the electromagnetic control force produced by EMCLD. The governing equations of the system are obtained using Hamilton＇s Principle and then reduced with the assumed-mode method. A simulation on vibration control of a cantilever beam is conducted under the velocity proportional feedback to demonstrate the energy dissipation capability of EMCLD, and the beam system with the same parameter is experimented. The results of experiment and simulation are compared and the results show that the EMCLD is an effective means for suppressing modal vibration. The results also indicate that the beam system has better control performance for larger control current. The EMCLD method presented in this paper provides an applicable and efficient tool for the vibration control of structures.展开更多
This article deals with evaluating the frequency response of functionally graded carbon nanotube reinforced magneto-electro-elastic(FG-CNTMEE)plates subjected to open and closed electro-magnetic circuit conditions.In ...This article deals with evaluating the frequency response of functionally graded carbon nanotube reinforced magneto-electro-elastic(FG-CNTMEE)plates subjected to open and closed electro-magnetic circuit conditions.In this regard finite element formulation has been derived.The plate kinematics adjudged via higher order shear deformation theory(HSDT)is considered for evaluation.The equations of motion are obtained with the help of Hamilton’s principle and solved using condensation technique.It is found that the convergence and accuracy of the present FE formulation is very good to address the vibration problem of FG-CNTMEE plate.For the first time,frequency response analysis of FG-CNTMEE plates considering the effect of various circuit conditions associated with parameters such as CNT distributions,volume fraction,skew angle,aspect ratio,length-to-thickness ratio and coupling fields has been carried out.The results of this article can serve as benchmark for future development and analysis of smart structures.展开更多
Objective To investigate the effects of extremely low frequency magnetic and electric fields （ELFEMFs） emitted from 380 kV transmission lines on some leukocyte differentiation antigens in dairy cows. Methods The stu...Objective To investigate the effects of extremely low frequency magnetic and electric fields （ELFEMFs） emitted from 380 kV transmission lines on some leukocyte differentiation antigens in dairy cows. Methods The study was carded out in 5 cows exposed to 1.98-3.28 μT of ELFEMFs and in 5 control cows exposed to 0.2-0.7 μT of ELFEMFs. Following haematological and immunologic parameters were measured in both groups： WBC, CD45R, CD6, CD4, CD8, CD21, and CD11B leukocyte antigen expression. Results Some of the haematological and immunologic parameters under investigation were similar in both groups. However, CD8 （T lymphocyte surface antigen） was higher in the exposed group （1.35 ±0.120 vs 0.50 ±0.14×10^3/mL）. Furthermore, the CD4/CD8 ratio （0.84 ±0.05 and 2.19±0.16 for exposed and not exposed cows respectively） and circadian rhythm were different between the two groups. Conclusion Exposure to ELFEMFs is responsible of the abnormal temporal variations and distribution of some haematological and immunological parameters in dairy cows.展开更多
This paper analyzes the eddy currents and the electro-magnetic forces on the lower hybrid wave (LHW) launching antenna on the superconducting Tohamak HT-7 by using a finite element circult method. A new iterative algo...This paper analyzes the eddy currents and the electro-magnetic forces on the lower hybrid wave (LHW) launching antenna on the superconducting Tohamak HT-7 by using a finite element circult method. A new iterative algorithm is developed to analyze the coupled magnetic fields Which are very difficult to be calculated. The method and results obtained are helpful to study the eddy currents and electro-magnetic forces on metal plates which are placed in a rather complicated electro-magnetic environment.展开更多
Employing even higher voltage level to promote power transmission economy is an important subject in the program of power transmission from west to east. The influence of electro-magnetic environment of transmission p...Employing even higher voltage level to promote power transmission economy is an important subject in the program of power transmission from west to east. The influence of electro-magnetic environment of transmission project being closely related with human health and construction cost has to be seriously considered before advancing transmission voltage. This paper analyzes and discusses overseas and domestic research achievements on radio interference, audible noise, power frequency electric field, power frequency magnetic fields, DC resultant field intensity and ion stream involved in power transmission at ultra-high-voltage (UHV)AC and ± 800 kV DC or even higher voltage levels. Suggestions on limiting electro-magnetic effects and their ceiling value as well as measures to improve electro-magnetic environment are put forward.展开更多
Aim of this work is to try to explain, on a Rational basis, some equations of Electro-Magnetism, which are based on Experimental data. Any Electric Field can produce a Field of many small Electric Dipoles, continuousl...Aim of this work is to try to explain, on a Rational basis, some equations of Electro-Magnetism, which are based on Experimental data. Any Electric Field can produce a Field of many small Electric Dipoles, continuously distributed in space. In a region, where the Electric Field is constant, in direction and magnitude, all the small Dipoles are parallel to the Electric Field, and are represented by a single, long, parallel to them, fixed in space, Electric Dipole, which is here called Compass. An Alternating current, in a straight Conductor, is studied, by a simple, short computer program, for step-by-step nonlinear dynamic analysis. It is found that, only an Alternating current, not a direct current, can produce an Electric Dipole, in a straight Conductor. The two above Dipoles (Compass-Conductor) are assumed with equal lengths ℓ, lying on two skew lines, perpendicular to each other, at a distance ℓ√2, thus forming, by their four ends, a Regular Tetrahedron, with side length ℓ. Repulsion, between Like Charges, obeys the simple Coulomb Electro-Static law. Whereas Interaction (Attraction or Repulsion), between Unlike Charges, obeys a more accurate Lennard-Jones law. The analysis of Dipole-Dipole (Compass-Conductor) Interaction is performed by hand calculator. The only out-of-balance forces, in the regular Tetrahedron, acting on the Rigid Conductor, are the so-called magnetic forces. Their direction is found, in a simple Rational way, with help of Regular Tetrahedron, without recoursing to a “right-hand-rule”. The proposed model is applied to 1) The force acting on an Electric Charge moving in a magnetic field. 2) The force acting on a Current carrying straight Conductor, due to a magnetic field. 3) The magnetic fields created around a Current carrying straight Conductor. In these applications, proposed model gives reasonable results. Particularly, in third application, results, obtained by proposed model, are found in satisfactory approximation with corresponding ones, obtained by an empirical formula, based on relevant Experimental observations of H.-C. Oersted and A.-M. Ampère. So, the reliability of proposed model is checked. Position and direction of magnetic field vector coincide with those of a corresponding fixed Compass of a constant Electric Field. Main point of present work is that, without introducing the concept of a magnetic field vector, by combining field of dipoles, produced by an electric field, with dipole of an alternating current carrying conductor, the magnetic forces can be determined.展开更多
The CsI（T1） crystal modules of the Beijing Spectrometer Ⅲ （BESⅢ） electro-magnetic calorimeter （EMC） were designed and assembled through Monte Carlo simulation and experiments. After the assembly was finished, ...The CsI（T1） crystal modules of the Beijing Spectrometer Ⅲ （BESⅢ） electro-magnetic calorimeter （EMC） were designed and assembled through Monte Carlo simulation and experiments. After the assembly was finished, the performance of each crystal module was tested by cosmic rays. All crystal modules were found to work well before the installation of EMC.展开更多
The advent of CUDA-enabled GPU makes it possible to provide cloud applications with high-performance data security services.Unfortunately,recent studies have shown that GPU-based applications are also susceptible to s...The advent of CUDA-enabled GPU makes it possible to provide cloud applications with high-performance data security services.Unfortunately,recent studies have shown that GPU-based applications are also susceptible to side-channel attacks.These published work studied the side-channel vulnerabilities of GPU-based AES implementations by taking the advantage of the cache sharing among multiple threads or high parallelism of GPUs.Therefore,for GPU-based bitsliced cryptographic implementations,which are immune to the cache-based attacks referred to above,only a power analysis method based on the high-parallelism of GPUs may be effective.However,the leakage model used in the power analysis is not efficient at all in practice.In light of this,we investigate electro-magnetic(EM)side-channel vulnerabilities of a GPU-based bitsliced AES implementation from the perspective of bit-level parallelism and thread-level parallelism in order to make the best of the localization effect of EM leakage with parallelism.Specifically,we propose efficient multi-bit and multi-thread combinational analysis techniques based on the intrinsic properties of bitsliced ciphers and the effect of multi-thread parallelism of GPUs,respectively.The experimental result shows that the proposed combinational analysis methods perform better than non-combinational and intuitive ones.Our research suggests that multi-thread leakages can be used to improve attacks if the multi-thread leakages are not synchronous in the time domain.展开更多
The advent of CUDA-enabled GPU makes it possible to provide cloud applications with high-performance data security services.Unfortunately,recent studies have shown that GPU-based applications are also susceptible to s...The advent of CUDA-enabled GPU makes it possible to provide cloud applications with high-performance data security services.Unfortunately,recent studies have shown that GPU-based applications are also susceptible to side-channel attacks.These published work studied the side-channel vulnerabilities of GPU-based AES implementations by taking the advantage of the cache sharing among multiple threads or high parallelism of GPUs.Therefore,for GPU-based bitsliced cryptographic implementations,which are immune to the cache-based attacks referred to above,only a power analysis method based on the high-parallelism of GPUs may be effective.However,the leakage model used in the power analysis is not efficient at all in practice.In light of this,we investigate electro-magnetic(EM)side-channel vulnerabilities of a GPU-based bitsliced AES implementation from the perspective of bit-level parallelism and thread-level parallelism in order to make the best of the localization effect of EM leakage with parallelism.Specifically,we propose efficient multi-bit and multi-thread combinational analysis techniques based on the intrinsic properties of bitsliced ciphers and the effect of multi-thread parallelism of GPUs,respectively.The experimental result shows that the proposed combinational analysis methods perform better than non-combinational and intuitive ones.Our research suggests that multi-thread leakages can be used to improve attacks if the multi-thread leakages are not synchronous in the time domain.展开更多
The concept of the memristor was proposed by Leon Chua in 1971, along with some electro-magnetic interpretations according to quasi-static expansion of Maxwell＇s equations. In 2003, Chua included the memristor into a...The concept of the memristor was proposed by Leon Chua in 1971, along with some electro-magnetic interpretations according to quasi-static expansion of Maxwell＇s equations. In 2003, Chua included the memristor into a four-element torus that has infinite circuit elements. This paper uses the quasi-static method to interpret every circuit element in the torus. Two examples are also provided to show how topologic structure of an element affects its electrical properties by affecting the dominant electro-magnetic field components. Additionally, it is proved that the circuit elements in the torus, except the resistive, capacitive and inductive elements, cannot exist independently. Moreover, the incorrectness in Chua＇s interpretation of the memristor, that the memristor cannot be interpreted with the transient quasi-static method due to its memory property, is pointed out. Finally, the limitations of the electro-magnetic interpretation method are discussed.展开更多
基金National Natural Science Foundation of China (50275114)
文摘This paper investigates vibration control of beam through electro-magnetic constrained layer damping （EMCLD） which consists of electromagnet layer, permanent magnet layer and viscoelastic damping layer. When the coil of the electromagnet is electrified with proper control strategy, the electromagnet can exert magnetic force opposite to the direction of structural deformation so that the structural vibration is attenuated. A mathematical model is developed based on the equivalent current method to calculate the electromagnetic control force produced by EMCLD. The governing equations of the system are obtained using Hamilton＇s Principle and then reduced with the assumed-mode method. A simulation on vibration control of a cantilever beam is conducted under the velocity proportional feedback to demonstrate the energy dissipation capability of EMCLD, and the beam system with the same parameter is experimented. The results of experiment and simulation are compared and the results show that the EMCLD is an effective means for suppressing modal vibration. The results also indicate that the beam system has better control performance for larger control current. The EMCLD method presented in this paper provides an applicable and efficient tool for the vibration control of structures.
文摘This article deals with evaluating the frequency response of functionally graded carbon nanotube reinforced magneto-electro-elastic(FG-CNTMEE)plates subjected to open and closed electro-magnetic circuit conditions.In this regard finite element formulation has been derived.The plate kinematics adjudged via higher order shear deformation theory(HSDT)is considered for evaluation.The equations of motion are obtained with the help of Hamilton’s principle and solved using condensation technique.It is found that the convergence and accuracy of the present FE formulation is very good to address the vibration problem of FG-CNTMEE plate.For the first time,frequency response analysis of FG-CNTMEE plates considering the effect of various circuit conditions associated with parameters such as CNT distributions,volume fraction,skew angle,aspect ratio,length-to-thickness ratio and coupling fields has been carried out.The results of this article can serve as benchmark for future development and analysis of smart structures.
文摘Objective To investigate the effects of extremely low frequency magnetic and electric fields （ELFEMFs） emitted from 380 kV transmission lines on some leukocyte differentiation antigens in dairy cows. Methods The study was carded out in 5 cows exposed to 1.98-3.28 μT of ELFEMFs and in 5 control cows exposed to 0.2-0.7 μT of ELFEMFs. Following haematological and immunologic parameters were measured in both groups： WBC, CD45R, CD6, CD4, CD8, CD21, and CD11B leukocyte antigen expression. Results Some of the haematological and immunologic parameters under investigation were similar in both groups. However, CD8 （T lymphocyte surface antigen） was higher in the exposed group （1.35 ±0.120 vs 0.50 ±0.14×10^3/mL）. Furthermore, the CD4/CD8 ratio （0.84 ±0.05 and 2.19±0.16 for exposed and not exposed cows respectively） and circadian rhythm were different between the two groups. Conclusion Exposure to ELFEMFs is responsible of the abnormal temporal variations and distribution of some haematological and immunological parameters in dairy cows.
文摘This paper analyzes the eddy currents and the electro-magnetic forces on the lower hybrid wave (LHW) launching antenna on the superconducting Tohamak HT-7 by using a finite element circult method. A new iterative algorithm is developed to analyze the coupled magnetic fields Which are very difficult to be calculated. The method and results obtained are helpful to study the eddy currents and electro-magnetic forces on metal plates which are placed in a rather complicated electro-magnetic environment.
文摘Employing even higher voltage level to promote power transmission economy is an important subject in the program of power transmission from west to east. The influence of electro-magnetic environment of transmission project being closely related with human health and construction cost has to be seriously considered before advancing transmission voltage. This paper analyzes and discusses overseas and domestic research achievements on radio interference, audible noise, power frequency electric field, power frequency magnetic fields, DC resultant field intensity and ion stream involved in power transmission at ultra-high-voltage (UHV)AC and ± 800 kV DC or even higher voltage levels. Suggestions on limiting electro-magnetic effects and their ceiling value as well as measures to improve electro-magnetic environment are put forward.
文摘Aim of this work is to try to explain, on a Rational basis, some equations of Electro-Magnetism, which are based on Experimental data. Any Electric Field can produce a Field of many small Electric Dipoles, continuously distributed in space. In a region, where the Electric Field is constant, in direction and magnitude, all the small Dipoles are parallel to the Electric Field, and are represented by a single, long, parallel to them, fixed in space, Electric Dipole, which is here called Compass. An Alternating current, in a straight Conductor, is studied, by a simple, short computer program, for step-by-step nonlinear dynamic analysis. It is found that, only an Alternating current, not a direct current, can produce an Electric Dipole, in a straight Conductor. The two above Dipoles (Compass-Conductor) are assumed with equal lengths ℓ, lying on two skew lines, perpendicular to each other, at a distance ℓ√2, thus forming, by their four ends, a Regular Tetrahedron, with side length ℓ. Repulsion, between Like Charges, obeys the simple Coulomb Electro-Static law. Whereas Interaction (Attraction or Repulsion), between Unlike Charges, obeys a more accurate Lennard-Jones law. The analysis of Dipole-Dipole (Compass-Conductor) Interaction is performed by hand calculator. The only out-of-balance forces, in the regular Tetrahedron, acting on the Rigid Conductor, are the so-called magnetic forces. Their direction is found, in a simple Rational way, with help of Regular Tetrahedron, without recoursing to a “right-hand-rule”. The proposed model is applied to 1) The force acting on an Electric Charge moving in a magnetic field. 2) The force acting on a Current carrying straight Conductor, due to a magnetic field. 3) The magnetic fields created around a Current carrying straight Conductor. In these applications, proposed model gives reasonable results. Particularly, in third application, results, obtained by proposed model, are found in satisfactory approximation with corresponding ones, obtained by an empirical formula, based on relevant Experimental observations of H.-C. Oersted and A.-M. Ampère. So, the reliability of proposed model is checked. Position and direction of magnetic field vector coincide with those of a corresponding fixed Compass of a constant Electric Field. Main point of present work is that, without introducing the concept of a magnetic field vector, by combining field of dipoles, produced by an electric field, with dipole of an alternating current carrying conductor, the magnetic forces can be determined.
文摘The CsI（T1） crystal modules of the Beijing Spectrometer Ⅲ （BESⅢ） electro-magnetic calorimeter （EMC） were designed and assembled through Monte Carlo simulation and experiments. After the assembly was finished, the performance of each crystal module was tested by cosmic rays. All crystal modules were found to work well before the installation of EMC.
基金This work was supported in part by National Natural Science Foundation of China(No.61632020,UI936209)Beijing National Science Foundation(No.4192067).
文摘The advent of CUDA-enabled GPU makes it possible to provide cloud applications with high-performance data security services.Unfortunately,recent studies have shown that GPU-based applications are also susceptible to side-channel attacks.These published work studied the side-channel vulnerabilities of GPU-based AES implementations by taking the advantage of the cache sharing among multiple threads or high parallelism of GPUs.Therefore,for GPU-based bitsliced cryptographic implementations,which are immune to the cache-based attacks referred to above,only a power analysis method based on the high-parallelism of GPUs may be effective.However,the leakage model used in the power analysis is not efficient at all in practice.In light of this,we investigate electro-magnetic(EM)side-channel vulnerabilities of a GPU-based bitsliced AES implementation from the perspective of bit-level parallelism and thread-level parallelism in order to make the best of the localization effect of EM leakage with parallelism.Specifically,we propose efficient multi-bit and multi-thread combinational analysis techniques based on the intrinsic properties of bitsliced ciphers and the effect of multi-thread parallelism of GPUs,respectively.The experimental result shows that the proposed combinational analysis methods perform better than non-combinational and intuitive ones.Our research suggests that multi-thread leakages can be used to improve attacks if the multi-thread leakages are not synchronous in the time domain.
基金supported in part by National Natural Science Foundation of China(No.61632020,UI936209)Beijing National Science Foundation(No.4192067).
文摘The advent of CUDA-enabled GPU makes it possible to provide cloud applications with high-performance data security services.Unfortunately,recent studies have shown that GPU-based applications are also susceptible to side-channel attacks.These published work studied the side-channel vulnerabilities of GPU-based AES implementations by taking the advantage of the cache sharing among multiple threads or high parallelism of GPUs.Therefore,for GPU-based bitsliced cryptographic implementations,which are immune to the cache-based attacks referred to above,only a power analysis method based on the high-parallelism of GPUs may be effective.However,the leakage model used in the power analysis is not efficient at all in practice.In light of this,we investigate electro-magnetic(EM)side-channel vulnerabilities of a GPU-based bitsliced AES implementation from the perspective of bit-level parallelism and thread-level parallelism in order to make the best of the localization effect of EM leakage with parallelism.Specifically,we propose efficient multi-bit and multi-thread combinational analysis techniques based on the intrinsic properties of bitsliced ciphers and the effect of multi-thread parallelism of GPUs,respectively.The experimental result shows that the proposed combinational analysis methods perform better than non-combinational and intuitive ones.Our research suggests that multi-thread leakages can be used to improve attacks if the multi-thread leakages are not synchronous in the time domain.
文摘The concept of the memristor was proposed by Leon Chua in 1971, along with some electro-magnetic interpretations according to quasi-static expansion of Maxwell＇s equations. In 2003, Chua included the memristor into a four-element torus that has infinite circuit elements. This paper uses the quasi-static method to interpret every circuit element in the torus. Two examples are also provided to show how topologic structure of an element affects its electrical properties by affecting the dominant electro-magnetic field components. Additionally, it is proved that the circuit elements in the torus, except the resistive, capacitive and inductive elements, cannot exist independently. Moreover, the incorrectness in Chua＇s interpretation of the memristor, that the memristor cannot be interpreted with the transient quasi-static method due to its memory property, is pointed out. Finally, the limitations of the electro-magnetic interpretation method are discussed.
