A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The ...A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The self-locking and virtual work principles were applied to studying the basic self-locking condition of the USM.In order to make the cooperation between the crutch and telescopic mechanism more harmonical,the unlocking time of the USM was calculated.A set of parameters were selected to build a virtual model and fabricate a prototype.Both the simulation and performance experiments were carried out in a pipe with a nominal inside diameter of 160 mm.The results show that USM enables the robot to move quickly in one way,and in the other way it helps the robot get self-locking with the pipe wall.The traction of the inchworm robot can rise to 1.2 kN,beyond the limitation of friction of 0.497 kN.展开更多
BACKGROUND Cervical degenerative disc(CDD)disease is a common type of spondylosis.Although anterior cervical discectomy and fusion(ACDF)is the preferred treatment for CDD disease,internal fixation with a titanium plat...BACKGROUND Cervical degenerative disc(CDD)disease is a common type of spondylosis.Although anterior cervical discectomy and fusion(ACDF)is the preferred treatment for CDD disease,internal fixation with a titanium plate may cause various complications.The invention of the ACDF with a self-locking fusion cage(ROI-C)has effectively decreased the incidence of postoperative complications.AIM To observe the outcomes of CDD disease treated by ACDF with a ROI-C.METHODS Ninety patients with CDD disease treated at our hospital from March 2019 to March 2021 were included.They were divided into two groups(control group and observation group,n=45 in each)using a random number table.Patients in the control group received ACDF plus internal fixation with a titanium plate.Those in the observation group received ACDF+ROI-C placement.The two groups of patients were compared in terms of surgical parameters,pain,cervical spine function,range of motion,and complications.RESULTS The two groups of patients showed no significant differences in surgical time,blood loss,drainage volume,and length of hospital stay(P>0.05).No significant differences in the visual analogue scale(VAS),Japanese Orthopedic Association(JOA),and neck disability index(NDI)scores were observed between the two groups before surgery(P>0.05).The VAS and NDI scores in the observation group were considerably lower than those in the control group after surgery;however,the JOA scores in the observation group were significantly higher than those in the control group(P<0.05).No significant differences were observed in cervical disc height and the range of motion of the superior or inferior adjacent vertebrae between the two groups before surgery(P>0.05).The disc height in the observation group was larger than that in the control group after surgery.The range of motion of both the superior and inferior adjacent vertebrae was significantly smaller in the observation group than in the control group(P<0.05).The incidence of complications was only 2.22% in the observation group compared to 15.56% in the control group,and the difference was statistically significant(P<0.05).CONCLUSION Cervical spine function restoration was better with ROI-C with internal fixation in ACDF than with conventional titanium plates in ACDF for CDD disease.展开更多
Air-tightness and energy consumption was measured in a one-family house built in 2009 and 2010.The air-tightness fulfilled the goals,which was set to 0.3 L/s·m^(2).The energy consumption was measured from the sta...Air-tightness and energy consumption was measured in a one-family house built in 2009 and 2010.The air-tightness fulfilled the goals,which was set to 0.3 L/s·m^(2).The energy consumption was measured from the start in May 2010.The figures in this report refer to measurements between May 2010 and October 2013 and are well below the authority demand of 55 kWh/m^(2)·year.展开更多
A new efficient meshless method based on the element-free Galerkin method is proposed to analyze the static deformation of thin and thick plate structures in this paper. Using the new 3D shell-like kinematics in analo...A new efficient meshless method based on the element-free Galerkin method is proposed to analyze the static deformation of thin and thick plate structures in this paper. Using the new 3D shell-like kinematics in analogy to the solid-shell concept of the finite element method, discretization is carried out by the nodes located on the upper and lower surfaces of the structures. The approximation of all unknown field variables is carried out by using the moving least squares （MLS） approximation scheme in the in-plane directions, while the linear interpolation is applied through the thickness direction. Thus, different boundary conditions are defined only using displacements and penalty method is used to enforce the essential boundary conditions. The constrained Galerkin weak form, which incorporates only dis- placement degrees of freedom （d.o.f.s）, is derived. A modified 3D constitutive relationship is adopted in order to avoid or eliminate some self-locking effects. The numeric efficiency of the proposed meshless formulation is illustrated by the numeric examples.展开更多
Background Intramedullary nails had been widely used in the treatment of long-bone fractures because of less interference of fractures and center bearing biomechanical advantage. However, it had been also found many s...Background Intramedullary nails had been widely used in the treatment of long-bone fractures because of less interference of fractures and center bearing biomechanical advantage. However, it had been also found many shortcomings such as broken nails, delayed healing and was modified in order to achieve better efficacy and reduce complications. The aim of the present study is to compare the efficacy of rotary self-locking intramedullary nails （RSIN） with that of interlocking intramedullary nails （IIN） in the treatment of long-bone fractures.展开更多
Purpose:To compare the stability of the posterior anatomic self-locking plate(PASP)with two types of popular reconstruction plate fixation,i.e.double reconstruction plate(DRP)and cross reconstruction plate(CRP),and to...Purpose:To compare the stability of the posterior anatomic self-locking plate(PASP)with two types of popular reconstruction plate fixation,i.e.double reconstruction plate(DRP)and cross reconstruction plate(CRP),and to explore the influence of sitting and turning right/left on implants.Methods:PASP,DRP and CRP were assembled on a finite element model of both-column fractures of the left acetabulum.A load of 600 N and a torque of 8 N·m were loaded on the S1 vertebral body to detect the change of stress and displacement when sitting and turning right/left.Results:The peak stress and displacement of the three kinds of fixation methods under all loading conditions were CRP>DRP>PASP.The peak stress and displacement of PASP are 313.5 MPa and 1.15 mm respectively when turning right;and the minimal was 234.0 Mpa and 0.619 mm when turning left.Conclusion:PASP can provide higher stability than DRP and CRP for both-column acetabular fractures.The rational movement after posterior DRP and PASP fixation for acetabular fracture is to turn to the ipsilateral side,which can avoid implant failure.展开更多
This paper proposes a novel clamping device for leveling equipment mounted on offshore oil platform jacket,which solves the problem of leveling equipment clamping lifting force of more than 2000 tons.The main features...This paper proposes a novel clamping device for leveling equipment mounted on offshore oil platform jacket,which solves the problem of leveling equipment clamping lifting force of more than 2000 tons.The main features are that lifting force transmits to clamp claw through wedge force amplifier,embed the teeth of claw into the pile,and the embedded depth increases with the lifting force,resulting in a gravitational self-locking function.This theoretical model of clamping device was established,and the force and material characteristic were analyzed,and the feasibility of the theoretical model was verified by thin shell elastic-plastic stability theory and thin-walled structures theory.An experimental prototype of clamping device was produced to test gravity self-locking function and bearable leveling force.Compared with the theoretical model and the experimental results,it proved that the embedded clamping devices have gravitational self-locking function and can meet the need of actual leveling equipment.展开更多
Rotating machines are very sensitive to mass unbalance which has a harmful effect on its running accuracy and service life. Therefore,a variety of dynamic balancing methods and devices are studied to reduce the vibrat...Rotating machines are very sensitive to mass unbalance which has a harmful effect on its running accuracy and service life. Therefore,a variety of dynamic balancing methods and devices are studied to reduce the vibration caused by mass unbalance. On-line active balancing is a new balancing procedure which is more convenient and precise than the previous methods. In this paper,an electromagnetic balancer based on ring coils and permanent magnets is presented. The balancer has a simple structure and the self-locking function without clutch,and transfers power by the non-contact electromagnetic field. In order to justify the rationality of its design,a two-dimension(2D) electromagnetic finite element model is conducted to verify that this magnetic circuit has no flux leakage and saturation. A three-dimension (3D) 1/10 model of the balancer is built to obtain the self-locking torque and driving torque. Based on the research work above,an electromagnetic balancer is developed. By testing the balancer using COCO80,it is verified effective to reduce the rotor unbalance at the speed of 1300 r/min.展开更多
Dual combs are an emerging tool to obtain unprecedented resolution, high sensitivity, ultrahigh accuracy, broad bandwidth, and ultrafast data updating rate in the fields of molecular spectroscopy, optical metrology, a...Dual combs are an emerging tool to obtain unprecedented resolution, high sensitivity, ultrahigh accuracy, broad bandwidth, and ultrafast data updating rate in the fields of molecular spectroscopy, optical metrology, as well as optical frequency synthesis. The recent progress in chip-based microcombs has promoted the on-chip dual-comb measuring systems to a new phase attributed to the large frequency spacing and broad spectrum. In this paper, we demonstrate proof-of-concept dual-comb generation with orthogonal polarization in a single microresonator through pumping both the transverse-electric （TE） and transverse-magnetic （TM） modes simultaneously. The two orthogonal polarized pumps are serf-oscillating in a fiber ring cavity. The generated dual comb exhibits excellent stability due to the intrinsic feedback mechanism of the sdf-locked scheme. The repetition rate of the two orthogonal combs is slightly different because of the mode spacing difference between the TE and TM modes. Such orthogonal polarized dual-combs could be a new comb source for out-of-lab applications in the fields of integrated spectroscopy, ranging measurement, optical frequency synthesis, and microwave comb generation.展开更多
Self-locked energy-absorbing systems have been proposed in previous studies to overcome the limitations associated with the round-tube systems because they can prevent the lateral splash of tubes from impact loadings ...Self-locked energy-absorbing systems have been proposed in previous studies to overcome the limitations associated with the round-tube systems because they can prevent the lateral splash of tubes from impact loadings without any constraints.In case of self-locked systems,the ellipse-shaped self-locked tube is considered to be an optimal design when compared with the ordinary circle-shaped self-locked tubes and other shaped self-locked tubes.In this study,we aim to theoretically analyze the ellipseshaped self-locked tubes.Further,a plastic hinge model is developed to predict the force-displacement relation of the tube,which is compared with the deformation process observed in the experiment and finite element method(FEM)simulation.Using this model,the effects of tuning the geometric parameters of the tube on the energy absorption performance,including the deformation efficiency,energy absorption capacity,and effective stroke ratio,are simulated and analyzed.Finally,a guideline is provided with respect to the design of the ellipse-shaped self-locked tube in engineering applications.展开更多
Epoxidation of the carbon-carbon double bonds on unsaturated rubber macromolecules can produce novel modified rubber species with special properties,and construct eco-friendly crosslinking pathway via the reaction of ...Epoxidation of the carbon-carbon double bonds on unsaturated rubber macromolecules can produce novel modified rubber species with special properties,and construct eco-friendly crosslinking pathway via the reaction of epoxide groups to solve the problems brought by conventional sulfur vulcanization system.In this contribution,a novel modified product of isobutylene isoprene rubber(IIR),epoxyfunctionalized IIR(EIIR)was successfully prepared by in situ epoxidation technique for the first time,and the crosslinking of EIIR was achieved by the reaction of oxirane groups with maleic anhydride(MAH)without additional additives.The reaction conditions for preparing EIIR were optimized through systematic research on the epoxidation process.Under optimal condition,the degree of epoxidation of the rubber reached around 99%without side reactions.The obtained EIIR/carbon black composites cured by MAH had excellent mechanical properties comparable to those of IIR composites.More importantly,compared with IIR composites,the air-tightness of the EIIR composites was improved by about 50%,and the flexural fatigue life of first-level cracks and sixth-level cracks was increased by several times.The significant improvement of these properties is of great significance for the application safety and energy saving of IIR materials.展开更多
This paper presents a 6-b successive approximation register （SAR） ADC at the sampling rate of 600 MHz in a 65 nm CMOS process. To pursue high speed, this design employs the idea of the 2-b/stage. Based on this, the ...This paper presents a 6-b successive approximation register （SAR） ADC at the sampling rate of 600 MHz in a 65 nm CMOS process. To pursue high speed, this design employs the idea of the 2-b/stage. Based on this, the proposed structure with a new switching procedure is presented. Compared with traditional structures, it optimizes problems cause by mismatches of DACs and saves power. In addition, this paper takes advantage of dis- tributed comparator topology to improve the speed, while the proposed structure and self-locking technique lighten the kickback and offset caused by multiple comparators. The measurement results demonstrate that the signal-to- noise plus distortion ratio （SNDR） is 32.13 dB and the spurious-free dynamic range （SFDR） is 44.05 dB at 600 MS/s with 5.6 MHz input. By contrast, the SNDR/SFDR respectively drops to 28.46/39.20 dB with Nyquist input. Fabricated in a TSMC 65 nm process, the SAR ADC core occupies an area of 0.045 mm2 and consumes power of 5.01 mW on a supply voltage of 1.2 V resulting in a figure of merit of 252 fJ/conversion-step.展开更多
Hemispherical Resonator Gyroscope(HRG)is a classical high precision Coriolis Vibration Gyroscope(CVG),which performs attitude estimation of carrier by detecting the precession of standing wave of resonator,thus,the dr...Hemispherical Resonator Gyroscope(HRG)is a classical high precision Coriolis Vibration Gyroscope(CVG),which performs attitude estimation of carrier by detecting the precession of standing wave of resonator,thus,the drift of standing wave of resonator has a great influence on the output accuracy of gyroscope,where the quality factor non-uniformity of resonator is one of main error sources.Ring electrode is a classical excitation structure of HRG because the standing wave can precess freely under its excitation,which makes the gyroscope have more accurate scale factor,larger measurement range and better dynamic characteristics.In this paper,the equations of motion of an ideal resonator excited by a ring electrode are derived by the elastic thin shell theory and Lagrange mechanical principle,then the corresponding equivalent mechanical model is established.According to the“average method”,it can be seen that the ideal resonator excited by the ring electrode works in integral mode,and any position in the circumferential direction of resonator can be a working point,which means that the quality factor non-uniformity has a great effect on the drift of standing wave.Therefore,the equations of motion of resonator with quality factor non-uniformity under the ring electrode excitation are deduced by the equivalent mechanical model,and the drift model of standing wave is established by the“average method”,it can be found that both the amplitude of quality factor non-uniformity and angle between the“inherent damping axis”and antinode axis of standing wave can affect the drift rate of standing wave.Moreover,the drift model indicates that if the input angular rate does not reach the threshold,the precession angular rate of standing wave will appear“self-locking”phenomenon,that is,the gyroscope will lose the integral effect.展开更多
基金Project(2007AA04Z256) supported by the National High-Tech Research and Development Program of China
文摘A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The self-locking and virtual work principles were applied to studying the basic self-locking condition of the USM.In order to make the cooperation between the crutch and telescopic mechanism more harmonical,the unlocking time of the USM was calculated.A set of parameters were selected to build a virtual model and fabricate a prototype.Both the simulation and performance experiments were carried out in a pipe with a nominal inside diameter of 160 mm.The results show that USM enables the robot to move quickly in one way,and in the other way it helps the robot get self-locking with the pipe wall.The traction of the inchworm robot can rise to 1.2 kN,beyond the limitation of friction of 0.497 kN.
文摘BACKGROUND Cervical degenerative disc(CDD)disease is a common type of spondylosis.Although anterior cervical discectomy and fusion(ACDF)is the preferred treatment for CDD disease,internal fixation with a titanium plate may cause various complications.The invention of the ACDF with a self-locking fusion cage(ROI-C)has effectively decreased the incidence of postoperative complications.AIM To observe the outcomes of CDD disease treated by ACDF with a ROI-C.METHODS Ninety patients with CDD disease treated at our hospital from March 2019 to March 2021 were included.They were divided into two groups(control group and observation group,n=45 in each)using a random number table.Patients in the control group received ACDF plus internal fixation with a titanium plate.Those in the observation group received ACDF+ROI-C placement.The two groups of patients were compared in terms of surgical parameters,pain,cervical spine function,range of motion,and complications.RESULTS The two groups of patients showed no significant differences in surgical time,blood loss,drainage volume,and length of hospital stay(P>0.05).No significant differences in the visual analogue scale(VAS),Japanese Orthopedic Association(JOA),and neck disability index(NDI)scores were observed between the two groups before surgery(P>0.05).The VAS and NDI scores in the observation group were considerably lower than those in the control group after surgery;however,the JOA scores in the observation group were significantly higher than those in the control group(P<0.05).No significant differences were observed in cervical disc height and the range of motion of the superior or inferior adjacent vertebrae between the two groups before surgery(P>0.05).The disc height in the observation group was larger than that in the control group after surgery.The range of motion of both the superior and inferior adjacent vertebrae was significantly smaller in the observation group than in the control group(P<0.05).The incidence of complications was only 2.22% in the observation group compared to 15.56% in the control group,and the difference was statistically significant(P<0.05).CONCLUSION Cervical spine function restoration was better with ROI-C with internal fixation in ACDF than with conventional titanium plates in ACDF for CDD disease.
文摘Air-tightness and energy consumption was measured in a one-family house built in 2009 and 2010.The air-tightness fulfilled the goals,which was set to 0.3 L/s·m^(2).The energy consumption was measured from the start in May 2010.The figures in this report refer to measurements between May 2010 and October 2013 and are well below the authority demand of 55 kWh/m^(2)·year.
基金supported by the National Natural Science Foundation of China (11172192)the College Postgraduate Research and Innovation Project of Jiangsu province (CXZZ12 0803)
文摘A new efficient meshless method based on the element-free Galerkin method is proposed to analyze the static deformation of thin and thick plate structures in this paper. Using the new 3D shell-like kinematics in analogy to the solid-shell concept of the finite element method, discretization is carried out by the nodes located on the upper and lower surfaces of the structures. The approximation of all unknown field variables is carried out by using the moving least squares （MLS） approximation scheme in the in-plane directions, while the linear interpolation is applied through the thickness direction. Thus, different boundary conditions are defined only using displacements and penalty method is used to enforce the essential boundary conditions. The constrained Galerkin weak form, which incorporates only dis- placement degrees of freedom （d.o.f.s）, is derived. A modified 3D constitutive relationship is adopted in order to avoid or eliminate some self-locking effects. The numeric efficiency of the proposed meshless formulation is illustrated by the numeric examples.
文摘Background Intramedullary nails had been widely used in the treatment of long-bone fractures because of less interference of fractures and center bearing biomechanical advantage. However, it had been also found many shortcomings such as broken nails, delayed healing and was modified in order to achieve better efficacy and reduce complications. The aim of the present study is to compare the efficacy of rotary self-locking intramedullary nails （RSIN） with that of interlocking intramedullary nails （IIN） in the treatment of long-bone fractures.
文摘Purpose:To compare the stability of the posterior anatomic self-locking plate(PASP)with two types of popular reconstruction plate fixation,i.e.double reconstruction plate(DRP)and cross reconstruction plate(CRP),and to explore the influence of sitting and turning right/left on implants.Methods:PASP,DRP and CRP were assembled on a finite element model of both-column fractures of the left acetabulum.A load of 600 N and a torque of 8 N·m were loaded on the S1 vertebral body to detect the change of stress and displacement when sitting and turning right/left.Results:The peak stress and displacement of the three kinds of fixation methods under all loading conditions were CRP>DRP>PASP.The peak stress and displacement of PASP are 313.5 MPa and 1.15 mm respectively when turning right;and the minimal was 234.0 Mpa and 0.619 mm when turning left.Conclusion:PASP can provide higher stability than DRP and CRP for both-column acetabular fractures.The rational movement after posterior DRP and PASP fixation for acetabular fracture is to turn to the ipsilateral side,which can avoid implant failure.
文摘This paper proposes a novel clamping device for leveling equipment mounted on offshore oil platform jacket,which solves the problem of leveling equipment clamping lifting force of more than 2000 tons.The main features are that lifting force transmits to clamp claw through wedge force amplifier,embed the teeth of claw into the pile,and the embedded depth increases with the lifting force,resulting in a gravitational self-locking function.This theoretical model of clamping device was established,and the force and material characteristic were analyzed,and the feasibility of the theoretical model was verified by thin shell elastic-plastic stability theory and thin-walled structures theory.An experimental prototype of clamping device was produced to test gravity self-locking function and bearable leveling force.Compared with the theoretical model and the experimental results,it proved that the embedded clamping devices have gravitational self-locking function and can meet the need of actual leveling equipment.
基金The National Science and Technology Major Project of China(No.2010ZX04012-014)
文摘Rotating machines are very sensitive to mass unbalance which has a harmful effect on its running accuracy and service life. Therefore,a variety of dynamic balancing methods and devices are studied to reduce the vibration caused by mass unbalance. On-line active balancing is a new balancing procedure which is more convenient and precise than the previous methods. In this paper,an electromagnetic balancer based on ring coils and permanent magnets is presented. The balancer has a simple structure and the self-locking function without clutch,and transfers power by the non-contact electromagnetic field. In order to justify the rationality of its design,a two-dimension(2D) electromagnetic finite element model is conducted to verify that this magnetic circuit has no flux leakage and saturation. A three-dimension (3D) 1/10 model of the balancer is built to obtain the self-locking torque and driving torque. Based on the research work above,an electromagnetic balancer is developed. By testing the balancer using COCO80,it is verified effective to reduce the rotor unbalance at the speed of 1300 r/min.
基金National Natural Science Foundation of China(NSFC)(61475188,61605151,61635013,61675231)Strategic Priority Research Program,Chinese Academy of Sciences(CAS)(XDB24030600)
文摘Dual combs are an emerging tool to obtain unprecedented resolution, high sensitivity, ultrahigh accuracy, broad bandwidth, and ultrafast data updating rate in the fields of molecular spectroscopy, optical metrology, as well as optical frequency synthesis. The recent progress in chip-based microcombs has promoted the on-chip dual-comb measuring systems to a new phase attributed to the large frequency spacing and broad spectrum. In this paper, we demonstrate proof-of-concept dual-comb generation with orthogonal polarization in a single microresonator through pumping both the transverse-electric （TE） and transverse-magnetic （TM） modes simultaneously. The two orthogonal polarized pumps are serf-oscillating in a fiber ring cavity. The generated dual comb exhibits excellent stability due to the intrinsic feedback mechanism of the sdf-locked scheme. The repetition rate of the two orthogonal combs is slightly different because of the mode spacing difference between the TE and TM modes. Such orthogonal polarized dual-combs could be a new comb source for out-of-lab applications in the fields of integrated spectroscopy, ranging measurement, optical frequency synthesis, and microwave comb generation.
基金the National Natural Science Foundation of China(Grant Nos.11622214,11472027,and 11202012)the Academic Excellence Foundation of Beihang University for PhD Students。
文摘Self-locked energy-absorbing systems have been proposed in previous studies to overcome the limitations associated with the round-tube systems because they can prevent the lateral splash of tubes from impact loadings without any constraints.In case of self-locked systems,the ellipse-shaped self-locked tube is considered to be an optimal design when compared with the ordinary circle-shaped self-locked tubes and other shaped self-locked tubes.In this study,we aim to theoretically analyze the ellipseshaped self-locked tubes.Further,a plastic hinge model is developed to predict the force-displacement relation of the tube,which is compared with the deformation process observed in the experiment and finite element method(FEM)simulation.Using this model,the effects of tuning the geometric parameters of the tube on the energy absorption performance,including the deformation efficiency,energy absorption capacity,and effective stroke ratio,are simulated and analyzed.Finally,a guideline is provided with respect to the design of the ellipse-shaped self-locked tube in engineering applications.
基金the National Key Research and Development Program of Chinathe National Natural Science Foundation of China(Nos.2022YFB3704800,2022YFB3704802 and 52273051)the Fundamental Research Funds for the Central Universities(No.JD2221)。
文摘Epoxidation of the carbon-carbon double bonds on unsaturated rubber macromolecules can produce novel modified rubber species with special properties,and construct eco-friendly crosslinking pathway via the reaction of epoxide groups to solve the problems brought by conventional sulfur vulcanization system.In this contribution,a novel modified product of isobutylene isoprene rubber(IIR),epoxyfunctionalized IIR(EIIR)was successfully prepared by in situ epoxidation technique for the first time,and the crosslinking of EIIR was achieved by the reaction of oxirane groups with maleic anhydride(MAH)without additional additives.The reaction conditions for preparing EIIR were optimized through systematic research on the epoxidation process.Under optimal condition,the degree of epoxidation of the rubber reached around 99%without side reactions.The obtained EIIR/carbon black composites cured by MAH had excellent mechanical properties comparable to those of IIR composites.More importantly,compared with IIR composites,the air-tightness of the EIIR composites was improved by about 50%,and the flexural fatigue life of first-level cracks and sixth-level cracks was increased by several times.The significant improvement of these properties is of great significance for the application safety and energy saving of IIR materials.
基金Project supported by the National High-Tech Research and Development Program of China(No.2013 AA014101)the National Science and Technology Program of China(No.2012BAI13B07)
文摘This paper presents a 6-b successive approximation register （SAR） ADC at the sampling rate of 600 MHz in a 65 nm CMOS process. To pursue high speed, this design employs the idea of the 2-b/stage. Based on this, the proposed structure with a new switching procedure is presented. Compared with traditional structures, it optimizes problems cause by mismatches of DACs and saves power. In addition, this paper takes advantage of dis- tributed comparator topology to improve the speed, while the proposed structure and self-locking technique lighten the kickback and offset caused by multiple comparators. The measurement results demonstrate that the signal-to- noise plus distortion ratio （SNDR） is 32.13 dB and the spurious-free dynamic range （SFDR） is 44.05 dB at 600 MS/s with 5.6 MHz input. By contrast, the SNDR/SFDR respectively drops to 28.46/39.20 dB with Nyquist input. Fabricated in a TSMC 65 nm process, the SAR ADC core occupies an area of 0.045 mm2 and consumes power of 5.01 mW on a supply voltage of 1.2 V resulting in a figure of merit of 252 fJ/conversion-step.
文摘Hemispherical Resonator Gyroscope(HRG)is a classical high precision Coriolis Vibration Gyroscope(CVG),which performs attitude estimation of carrier by detecting the precession of standing wave of resonator,thus,the drift of standing wave of resonator has a great influence on the output accuracy of gyroscope,where the quality factor non-uniformity of resonator is one of main error sources.Ring electrode is a classical excitation structure of HRG because the standing wave can precess freely under its excitation,which makes the gyroscope have more accurate scale factor,larger measurement range and better dynamic characteristics.In this paper,the equations of motion of an ideal resonator excited by a ring electrode are derived by the elastic thin shell theory and Lagrange mechanical principle,then the corresponding equivalent mechanical model is established.According to the“average method”,it can be seen that the ideal resonator excited by the ring electrode works in integral mode,and any position in the circumferential direction of resonator can be a working point,which means that the quality factor non-uniformity has a great effect on the drift of standing wave.Therefore,the equations of motion of resonator with quality factor non-uniformity under the ring electrode excitation are deduced by the equivalent mechanical model,and the drift model of standing wave is established by the“average method”,it can be found that both the amplitude of quality factor non-uniformity and angle between the“inherent damping axis”and antinode axis of standing wave can affect the drift rate of standing wave.Moreover,the drift model indicates that if the input angular rate does not reach the threshold,the precession angular rate of standing wave will appear“self-locking”phenomenon,that is,the gyroscope will lose the integral effect.
