In the current practical science, the accuracy in the formability of metal alloys being the goal when using electromagnetic forming (EMF) technology, which is a high-speed processing technology that uses Lorentz force...In the current practical science, the accuracy in the formability of metal alloys being the goal when using electromagnetic forming (EMF) technology, which is a high-speed processing technology that uses Lorentz forces to achieve plastic deformation of sheet metal;according to the previous analysis, the results have shown that in most cases, the Lorentz force acting on the workpiece (metal) is not uniform, there are uneven axial deformations of the metal plates which prevent the rapid advancement of today’s technology. In this article, we presented some advanced analyzes which will lead us to improve the technical solution for the problems of non-uniform axial deformations of the metals in the traditional tube electromagnetic forming technology (EMF). A field shaper is used as a practical forming tool to influence the magnetic field and magnetic pressure distribution, thereby improving the forming ability and result during the electromagnetic forming (EMF) process and we see that induced eddy current control is realized by changing the structural parameters of the magnetic field shaper;which improves the strength and controllability of the magnetic force that acts on the workpiece;thereby a greater radial magnetic pressure can be achieved with field shaper than the case without it;the field shaper regulates the electromagnetic force, the distribution of the magnetic pressure decreases, and the uniform force area of the tube increases which effectively enhances the uniform range of the pipe electromagnetic bulging and the electromagnetic induction coupling between the coil and the metallic workpiece is generally required to produce the Lorentz forces. Using COMSOL Multiphysics® simulation software helped us to accurately represent the real world, simulating multiple physical effects that happened in this model during the process.展开更多
In an exhibition area of the World Economic Forum's (WEF) Annual Meeti ng of the New Cham pions in China's northeastern coastal city of Dalian, a robot was performing a surgical operation on a rose. The volunt...In an exhibition area of the World Economic Forum's (WEF) Annual Meeti ng of the New Cham pions in China's northeastern coastal city of Dalian, a robot was performing a surgical operation on a rose. The volunteers in the booth invited visitors to have a go at running the machine, which was developed by U.S. company Intuitive Surgical and has been used in 6 million successful surgeries worldwide. Over 110,000 of these were done in China, which has around 80 such robots in use in hospitals.展开更多
In this paper,the influence of various field shapers and their shapes on the distribution of the magnetic flux densities and applied forces on the work-piece in the electromagnetic inward tube forming are studied nume...In this paper,the influence of various field shapers and their shapes on the distribution of the magnetic flux densities and applied forces on the work-piece in the electromagnetic inward tube forming are studied numerically using the FEA software MAXWELL.First the model was verified with experimental results and thereafter four kinds of field shapers(conical,cylindrical,concave and convex)were considered.Effects of their geometries,such as air gap between field shaper and tube work-piece,height of the step in single and multiple stepped field shaper on magnetic flux densities and magnetic pressures were studied.The results of this research can be applied to design field shaper,tube compression technology,and improve the efficiency of the coil.It is seen that magnetic force decreases if height of step in convex field shaper increases but effective forming region enlarges.Decreasing air gap has also a positive influence on magnetic field increase.Though the object of this research is limited to field shaper for inward tube forming,the results can also be applied to the field shaper for tube bulging.展开更多
Wave shaper effect on formation behavior and penetration performance of reactive liner shaped charge(RLSC)are investigated by experiments and simulations.The reactive materials liner with a density of2.3 g/cm^3 is fab...Wave shaper effect on formation behavior and penetration performance of reactive liner shaped charge(RLSC)are investigated by experiments and simulations.The reactive materials liner with a density of2.3 g/cm^3 is fabricated by cold pressing at a pressure of 300 MPa and sintering at a temperature of 380℃.Experiments of the RLSC with and without wave shaper against steel plates are carried out at standoffs of0.5,1.0,and 1.5 CD(charge diameter),respectively.The experimental results show that the penetration depths and structural damage effects of steel plates decrease with increasing the standoff,while the penetration depths and the damage effects of RLSC without wave shaper are much greater than that with wave shaper at the same standoff.To understand the unusual experimental results,numerical simulations based on AUTODYN-2 D code are conducted to discuss the wave shaper effect,including the propagation behavior of detonation wave,the velocity and temperature distribution of reactive jet,and penetration depth of reactive jet.The simulations indicate that,compared with RLSC without wave shaper,there is a higher temperature produced inside reactive jet with wave shaper.This unusual temperature rise effects are likely to be an important mechanism to cause the initiation delay time of reactive jet to decline,which results in significantly decreasing its penetration performance.展开更多
In the current study, streak camera was used to find concentricity of the assembly during detonation,investigate and compare shock front within the high explosive and behavior of the shock front on the surface of the ...In the current study, streak camera was used to find concentricity of the assembly during detonation,investigate and compare shock front within the high explosive and behavior of the shock front on the surface of the liner, one containing wave shaper and the other without wave shaper. Streaks revealed that the whole assembly was concentric till the formation of the jet. Observed streaks vindicate the uniform propagation of shock front in both the cases. Results obtained for shock front velocities are in agreement with those obtained from simulations. In the presence of wave shaper higher shock front velocity was observed both in simulation and experiment. Simulation without wave-shaper showed that shock front struck the copper cone at grazing angle while in the presence of wave-shaper it struck at an angle of 125.展开更多
In this paper,we present a novel ultrashort pulse shaper based on complex-modulated long-period-grating coupler（CM-LPGC）.Temporal rectangular waveform with 2-ps full width at half maximum（FWHM） is obtained by tran...In this paper,we present a novel ultrashort pulse shaper based on complex-modulated long-period-grating coupler（CM-LPGC）.Temporal rectangular waveform with 2-ps full width at half maximum（FWHM） is obtained by transforming the input Gaussian pulse.Tolerances of the CM-LPGC-based shaper to various non-ideal excitation conditions and fabricating errors are investigated.Results confirm that CM-LPGC is stable and suitable for optical pulse shaping operation.展开更多
When a wave shaper is embedded in a liner,Mach wave will emerge above the liner,which affects the head shape of an explosively formed projectile.Mach wave parameters,including radius and pressure need to be determined...When a wave shaper is embedded in a liner,Mach wave will emerge above the liner,which affects the head shape of an explosively formed projectile.Mach wave parameters,including radius and pressure need to be determined to effectively match Mach wave with the liner,so that a good head shape can be obtained.An analytical calculation model for Mach wave parameter is presented based on three-shock theory,and the theoretical values agree well with the experimental ones.The analysis shows that when the radius of the wave shaper is constant,the radius of the Mach wave increases,whereas the pressure decreases while increasing the distance between the liner and the wave shaper.When the distance between the liner and the wave shaper is constant,the radius of the Mach wave increases,whereas the pressure decreases when decreasing the radius of the wave shaper.展开更多
In this paper,the flatness control technology AnShaper^(TM) for cold-rolling mill and industry application are introduced.AnShaper^(TM) includes;partitioning piezomagnetic shape meter for flatness measurement for cold...In this paper,the flatness control technology AnShaper^(TM) for cold-rolling mill and industry application are introduced.AnShaper^(TM) includes;partitioning piezomagnetic shape meter for flatness measurement for cold-rolling strip;flatness measured signals processing system based on digital signal processing(DSP);flatness feedback control model system based on the control efficiency of flatness control actuators and model adaptive function.The application verifies that strip flatness can meet the need of high quality product by using AnShaperTM.The average flatness quality is about 5Ⅰ-unit and the 0.18 mm ultrathin thickness strip flatness is 10Ⅰ-unit.展开更多
A new current feedback amplifier (CFA) based dual-input differentiator (DID) design with grounded capacitor is presented;its time constant (τo) is independently tunable by a single resistor. The proposed circuit yiel...A new current feedback amplifier (CFA) based dual-input differentiator (DID) design with grounded capacitor is presented;its time constant (τo) is independently tunable by a single resistor. The proposed circuit yields a true DID function with ideal CFA devices. Analysis with nonideal devices having parasitic capacitance (Cp) shows extremely low but finite phase error (θe);suitable design θe could be minimized significantly. The design is practically active-insensitive relative to port mismatch errors (ε) of the active element. An allpass phase shifter circuit implementation is derived with slight modification of the differentiator. Satisfactory experimental results had been verified on typical wave processing and phase-selective filter design applications.展开更多
Radioactive Ion Beam Line in Lanzhou (RIBLL) is the heavy ion radiation beam equipment on Heavy Ion Accelerator in Lanzhou, which can provide a variety of Radioactive Ion Beam （RIB）for physical experiments.In order ...Radioactive Ion Beam Line in Lanzhou (RIBLL) is the heavy ion radiation beam equipment on Heavy Ion Accelerator in Lanzhou, which can provide a variety of Radioactive Ion Beam （RIB）for physical experiments.In order to improve the efficiency and accuracy of the experiments, we need a high-performance Parallel Plate Avalanche Counter(PPAC) to monitor the RIB online and to measure the track of the incident particles and reaction products.展开更多
Optimal detection of liquid ionization calorimeter signal in experimental particle physics is considered. A few linear and nonlinear approaches for amplitude and arrival time estimation based on the χ2 function are c...Optimal detection of liquid ionization calorimeter signal in experimental particle physics is considered. A few linear and nonlinear approaches for amplitude and arrival time estimation based on the χ2 function are compared in simulation considering the noise sample correlation introduced by the analog pulse shaper. The estimation bias of the first-order approximation, a.k.a linear optimal filtering, is studied and contrasted to those of the second-order as well as the exhaustive search. A gradient-descent technique is presented as an alternative to the exhaustive search with significantly reduced search time and computation complexity. Results from various pulse shapers including the CR-RC2, CR-RC3, and CR2-RC2 are also compared.展开更多
In order to improve the damage threshold and enlarge the aperture of a laser beam shaper, photolithographic patterning technology is adopted to design a new type of liquid crystal binary mask. The inherent conductive ...In order to improve the damage threshold and enlarge the aperture of a laser beam shaper, photolithographic patterning technology is adopted to design a new type of liquid crystal binary mask. The inherent conductive metal layer of commercial liquid crystal electro-optical spatial light modulators is replaced by azobenzene-based photoalignment layers patterned by noncontact photolithography. Using the azobenzene-based photoalignment layer, a liquid crystal binary mask for beam shaping is fabricated. In addition, the shaping ability, damage threshold, write/erase flexibility and stability of the liquid crystal binary mask are tested. Using a 1 Hz near-IR(1064 nm) laser, the multiple-shot nanosecond damage threshold of the liquid crystal mask is measured to be higher than 15 J/cm^2. The damage threshold of the azobenzenebased photoalignment layer is higher than 50 J/cm^2 under the same testing conditions.展开更多
An ultra-low power complementary metal-oxide-semiconductor （CMOS） front-end readout ASIC was developed for a portable digital radiation detector. The ASIC having a charge sensitive amplifier and a semi-Gaussian puls...An ultra-low power complementary metal-oxide-semiconductor （CMOS） front-end readout ASIC was developed for a portable digital radiation detector. The ASIC having a charge sensitive amplifier and a semi-Gaussian pulse-shaper was produced using the CSMC 0.5 μm DPDM process. The ENC noise of 363 e at 0 pF with a noise slope of 23 e/pF complies with the stringent low noise requirements. The peaking time was 250 ns at a 100 mV/fC conversion gain （detector capacitance is 20 pF）. By operating this frontend readout ASIC in the weak inversion region, the ultra-low power dissipation is only 0.1 mW/channel （3.0 V） Simulations and test results suggest that this design gives lower power consumption than the front-end readout ASICs working in the strong inversion and is appropriate for the portable digital radiation detectors.展开更多
文摘In the current practical science, the accuracy in the formability of metal alloys being the goal when using electromagnetic forming (EMF) technology, which is a high-speed processing technology that uses Lorentz forces to achieve plastic deformation of sheet metal;according to the previous analysis, the results have shown that in most cases, the Lorentz force acting on the workpiece (metal) is not uniform, there are uneven axial deformations of the metal plates which prevent the rapid advancement of today’s technology. In this article, we presented some advanced analyzes which will lead us to improve the technical solution for the problems of non-uniform axial deformations of the metals in the traditional tube electromagnetic forming technology (EMF). A field shaper is used as a practical forming tool to influence the magnetic field and magnetic pressure distribution, thereby improving the forming ability and result during the electromagnetic forming (EMF) process and we see that induced eddy current control is realized by changing the structural parameters of the magnetic field shaper;which improves the strength and controllability of the magnetic force that acts on the workpiece;thereby a greater radial magnetic pressure can be achieved with field shaper than the case without it;the field shaper regulates the electromagnetic force, the distribution of the magnetic pressure decreases, and the uniform force area of the tube increases which effectively enhances the uniform range of the pipe electromagnetic bulging and the electromagnetic induction coupling between the coil and the metallic workpiece is generally required to produce the Lorentz forces. Using COMSOL Multiphysics® simulation software helped us to accurately represent the real world, simulating multiple physical effects that happened in this model during the process.
文摘In an exhibition area of the World Economic Forum's (WEF) Annual Meeti ng of the New Cham pions in China's northeastern coastal city of Dalian, a robot was performing a surgical operation on a rose. The volunteers in the booth invited visitors to have a go at running the machine, which was developed by U.S. company Intuitive Surgical and has been used in 6 million successful surgeries worldwide. Over 110,000 of these were done in China, which has around 80 such robots in use in hospitals.
文摘In this paper,the influence of various field shapers and their shapes on the distribution of the magnetic flux densities and applied forces on the work-piece in the electromagnetic inward tube forming are studied numerically using the FEA software MAXWELL.First the model was verified with experimental results and thereafter four kinds of field shapers(conical,cylindrical,concave and convex)were considered.Effects of their geometries,such as air gap between field shaper and tube work-piece,height of the step in single and multiple stepped field shaper on magnetic flux densities and magnetic pressures were studied.The results of this research can be applied to design field shaper,tube compression technology,and improve the efficiency of the coil.It is seen that magnetic force decreases if height of step in convex field shaper increases but effective forming region enlarges.Decreasing air gap has also a positive influence on magnetic field increase.Though the object of this research is limited to field shaper for inward tube forming,the results can also be applied to the field shaper for tube bulging.
基金funded under the National Natural Science Foundation of China (No. U1730112)supported by the State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology
文摘Wave shaper effect on formation behavior and penetration performance of reactive liner shaped charge(RLSC)are investigated by experiments and simulations.The reactive materials liner with a density of2.3 g/cm^3 is fabricated by cold pressing at a pressure of 300 MPa and sintering at a temperature of 380℃.Experiments of the RLSC with and without wave shaper against steel plates are carried out at standoffs of0.5,1.0,and 1.5 CD(charge diameter),respectively.The experimental results show that the penetration depths and structural damage effects of steel plates decrease with increasing the standoff,while the penetration depths and the damage effects of RLSC without wave shaper are much greater than that with wave shaper at the same standoff.To understand the unusual experimental results,numerical simulations based on AUTODYN-2 D code are conducted to discuss the wave shaper effect,including the propagation behavior of detonation wave,the velocity and temperature distribution of reactive jet,and penetration depth of reactive jet.The simulations indicate that,compared with RLSC without wave shaper,there is a higher temperature produced inside reactive jet with wave shaper.This unusual temperature rise effects are likely to be an important mechanism to cause the initiation delay time of reactive jet to decline,which results in significantly decreasing its penetration performance.
文摘In the current study, streak camera was used to find concentricity of the assembly during detonation,investigate and compare shock front within the high explosive and behavior of the shock front on the surface of the liner, one containing wave shaper and the other without wave shaper. Streaks revealed that the whole assembly was concentric till the formation of the jet. Observed streaks vindicate the uniform propagation of shock front in both the cases. Results obtained for shock front velocities are in agreement with those obtained from simulations. In the presence of wave shaper higher shock front velocity was observed both in simulation and experiment. Simulation without wave-shaper showed that shock front struck the copper cone at grazing angle while in the presence of wave-shaper it struck at an angle of 125.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61007007 and 61101110)the Foundation of Beijing Municipal Committee of CPC Organization Department (Grant No. 2012D005002000001)
文摘In this paper,we present a novel ultrashort pulse shaper based on complex-modulated long-period-grating coupler（CM-LPGC）.Temporal rectangular waveform with 2-ps full width at half maximum（FWHM） is obtained by transforming the input Gaussian pulse.Tolerances of the CM-LPGC-based shaper to various non-ideal excitation conditions and fabricating errors are investigated.Results confirm that CM-LPGC is stable and suitable for optical pulse shaping operation.
文摘When a wave shaper is embedded in a liner,Mach wave will emerge above the liner,which affects the head shape of an explosively formed projectile.Mach wave parameters,including radius and pressure need to be determined to effectively match Mach wave with the liner,so that a good head shape can be obtained.An analytical calculation model for Mach wave parameter is presented based on three-shock theory,and the theoretical values agree well with the experimental ones.The analysis shows that when the radius of the wave shaper is constant,the radius of the Mach wave increases,whereas the pressure decreases while increasing the distance between the liner and the wave shaper.When the distance between the liner and the wave shaper is constant,the radius of the Mach wave increases,whereas the pressure decreases when decreasing the radius of the wave shaper.
文摘In this paper,the flatness control technology AnShaper^(TM) for cold-rolling mill and industry application are introduced.AnShaper^(TM) includes;partitioning piezomagnetic shape meter for flatness measurement for cold-rolling strip;flatness measured signals processing system based on digital signal processing(DSP);flatness feedback control model system based on the control efficiency of flatness control actuators and model adaptive function.The application verifies that strip flatness can meet the need of high quality product by using AnShaperTM.The average flatness quality is about 5Ⅰ-unit and the 0.18 mm ultrathin thickness strip flatness is 10Ⅰ-unit.
文摘A new current feedback amplifier (CFA) based dual-input differentiator (DID) design with grounded capacitor is presented;its time constant (τo) is independently tunable by a single resistor. The proposed circuit yields a true DID function with ideal CFA devices. Analysis with nonideal devices having parasitic capacitance (Cp) shows extremely low but finite phase error (θe);suitable design θe could be minimized significantly. The design is practically active-insensitive relative to port mismatch errors (ε) of the active element. An allpass phase shifter circuit implementation is derived with slight modification of the differentiator. Satisfactory experimental results had been verified on typical wave processing and phase-selective filter design applications.
文摘Radioactive Ion Beam Line in Lanzhou (RIBLL) is the heavy ion radiation beam equipment on Heavy Ion Accelerator in Lanzhou, which can provide a variety of Radioactive Ion Beam （RIB）for physical experiments.In order to improve the efficiency and accuracy of the experiments, we need a high-performance Parallel Plate Avalanche Counter(PPAC) to monitor the RIB online and to measure the track of the incident particles and reaction products.
文摘Optimal detection of liquid ionization calorimeter signal in experimental particle physics is considered. A few linear and nonlinear approaches for amplitude and arrival time estimation based on the χ2 function are compared in simulation considering the noise sample correlation introduced by the analog pulse shaper. The estimation bias of the first-order approximation, a.k.a linear optimal filtering, is studied and contrasted to those of the second-order as well as the exhaustive search. A gradient-descent technique is presented as an alternative to the exhaustive search with significantly reduced search time and computation complexity. Results from various pulse shapers including the CR-RC2, CR-RC3, and CR2-RC2 are also compared.
基金supported by the International Partnership Program of Chinese Academy of Sciences (No. 181231KYSB20170022)
文摘In order to improve the damage threshold and enlarge the aperture of a laser beam shaper, photolithographic patterning technology is adopted to design a new type of liquid crystal binary mask. The inherent conductive metal layer of commercial liquid crystal electro-optical spatial light modulators is replaced by azobenzene-based photoalignment layers patterned by noncontact photolithography. Using the azobenzene-based photoalignment layer, a liquid crystal binary mask for beam shaping is fabricated. In addition, the shaping ability, damage threshold, write/erase flexibility and stability of the liquid crystal binary mask are tested. Using a 1 Hz near-IR(1064 nm) laser, the multiple-shot nanosecond damage threshold of the liquid crystal mask is measured to be higher than 15 J/cm^2. The damage threshold of the azobenzenebased photoalignment layer is higher than 50 J/cm^2 under the same testing conditions.
基金Supported by the National Natural Science Foundation of China(No. BK2007026)the 333 High-Level Personnel Training Project of Jiangsu Province (No. 2007124)
文摘An ultra-low power complementary metal-oxide-semiconductor （CMOS） front-end readout ASIC was developed for a portable digital radiation detector. The ASIC having a charge sensitive amplifier and a semi-Gaussian pulse-shaper was produced using the CSMC 0.5 μm DPDM process. The ENC noise of 363 e at 0 pF with a noise slope of 23 e/pF complies with the stringent low noise requirements. The peaking time was 250 ns at a 100 mV/fC conversion gain （detector capacitance is 20 pF）. By operating this frontend readout ASIC in the weak inversion region, the ultra-low power dissipation is only 0.1 mW/channel （3.0 V） Simulations and test results suggest that this design gives lower power consumption than the front-end readout ASICs working in the strong inversion and is appropriate for the portable digital radiation detectors.
