A phase-shifting digital holography scheme developed to investigate internal defects in artworks is described. Phase-shifting is utilized to obtain a clear reconstructed object wave from a rough surface texture. A rev...A phase-shifting digital holography scheme developed to investigate internal defects in artworks is described. Phase-shifting is utilized to obtain a clear reconstructed object wave from a rough surface texture. A reverse-transform algorithm is employed to reconstruct the object wave on its original position of unknown distance or the imaging position from the object wave information on the holographic plane. To get the clearest reconstruction the exact registration of the unknown distance is determined by applying the intensity sum as the auto-focusing function, The spatial resolution of the reconstruction image is also investigated for a variety of affecting factors. Laboratory results of reconstruction images under deformation are presented.展开更多
An improved in-plane insensitive double-aperture digital speckle shearing interferometric technique is proposed to measure the first derivative of out-of-plane displacement （slope）. The temporal phase-shifting metho...An improved in-plane insensitive double-aperture digital speckle shearing interferometric technique is proposed to measure the first derivative of out-of-plane displacement （slope）. The temporal phase-shifting method is used for the quantitative analysis of fringes. The designed system employs a double-aperture arrange- ment placed in front of the imaging lens. A glass wedge covers one of the two apertures to introduce a laterally shear. The experimental specimen is a circular aluminum plate, clamped along its edge and subjected to both out- of-plane deflection and in-plane rotation. Experimental results show that the fringes obtained from the proposed optical configuration represent pure slope contour distributions, and that the contributions from the in-plane dis- placement components are completely eliminated. Theoretical and experimental results are in good agreement.展开更多
This paper deals with the mode I crack problem of a cracked rubber sheet under plane stress condition using the delicate digital moiré technique. Through the four step phaseshifting method of automated fringe ana...This paper deals with the mode I crack problem of a cracked rubber sheet under plane stress condition using the delicate digital moiré technique. Through the four step phaseshifting method of automated fringe analysis, the displacement fields in the Cartesian coordinate system are given. By the coordinate-transform equation, the radial and circular displacement distributions in the polar coordinate system are obtained. The displacement isoline distributions and displacement vector distributions near the crack tip are discussed. The strain isoline distributions near the crack tip are also analyzed in this paper. Finally, the distribution rules for the mechanical fields near the crack tip are discussed with the sector division method.展开更多
A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)paramet...A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control parameters.The proposed digital system can be combined with a conventional analog data acquisition system to provide more flexibility.The performance of the combined system was veri-fied using experimental data.展开更多
We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the ...We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the multiple objects beams and the one reference beam is used to simultaneously encrypt multiple objects into a ciphertext. During decryption, each three-dimensional object can be decrypted independently without having to decrypt other objects. Since the single- pixel digital holography based on compressive sensing theory is introduced, the encrypted data of this method is effectively reduced. In addition, recording fewer encrypted data can greatly reduce the bandwidth of network transmission. Moreover, the compressive sensing essentially serves as a secret key that makes an intruder attack invalid, which means that the system is more secure than the conventional encryption method. Simulation results demonstrate the feasibility of the proposed method and show that the system has good security performance.展开更多
BACKGROUND Trigger digit is a common disorder of the hand associated with carpal tunnel syndrome.Carpal tunnel release(CTR)surgery may be a risk factor for trigger digit development;however,the association between sur...BACKGROUND Trigger digit is a common disorder of the hand associated with carpal tunnel syndrome.Carpal tunnel release(CTR)surgery may be a risk factor for trigger digit development;however,the association between surgical approach to CTR and postoperative trigger digit is equivocal.AIM To investigate patient risk factors for trigger digit development following either open carpal tunnel release(OCTR)or endoscopic carpal tunnel release(ECTR).METHODS This retrospective chart analysis evaluated 967 CTR procedures from 694 patients for the development of postoperative trigger digit.Patients were stratified according to the technique utilized for their CTR,either open or endoscopic.The development of postoperative trigger digit was evaluated at three time points:within 6 mo following CTR,between 6 mo and 12 mo following CTR,and after 12 mo following CTR.Firth’s penalized likelihood logistic regression was conducted to evaluate sociodemographic and patient comorbidities as potential independent risk factors for trigger digit.Secondary regression models were conducted within each surgical group to reveal any potential interaction effects between surgical approach and patient risk factors for the development of postoperative trigger digit.RESULTS A total of 47 hands developed postoperative trigger digit following 967 CTR procedures(4.9%).In total,64 digits experienced postoperative triggering.The long finger was most commonly affected.There was no significant difference between the open and endoscopic groups for trigger digit development at all three time points following CTR.Furthermore,there were no significant independent risk factors for postoperative trigger digit;however,within group analysis revealed a significant interaction effect between gender and surgical approach(P=0.008).Females were more likely to develop postoperative trigger digit than males after OCTR(OR=3.992),but were less likely to develop postoperative trigger digit than males after ECTR(OR=0.489).CONCLUSION Patient comorbidities do not influence the development of trigger digit following CTR.Markedly,gender differences for postoperative trigger digit may depend on surgical approach to CTR.展开更多
Digital control system for pulsed MIG welding power based on STM32 is set up with 32-bit STM32FlO3ZET6 directing against the pulse waveform modulation of pulsed MIG welding. High-frequency inverter and medium-low freq...Digital control system for pulsed MIG welding power based on STM32 is set up with 32-bit STM32FlO3ZET6 directing against the pulse waveform modulation of pulsed MIG welding. High-frequency inverter and medium-low frequency pulse waveform modulation of pulsed MIG welding are realized by using the integrated PWM module within STM32 to generate PWM signals of phase-shifted full-bridge soft-switching and constant-current control of output current is achieved by means of anti-windup PI control algorithm to improve the stability and reliability of control system. Experimental results demonstrate that the designed digital control system based on STM32 can achieve pegrect pulsed MIG welding technique with stable welding process and good weld appearance, fully demonstrating the advantages of digital control based on STM32.展开更多
BACKGROUND Trigger finger is a common disorder of the hand that can cause disabling symptoms.Treatment options range from conservative management with observation and splinting,to surgical release,but there is current...BACKGROUND Trigger finger is a common disorder of the hand that can cause disabling symptoms.Treatment options range from conservative management with observation and splinting,to surgical release,but there is currently not a consensus on a treatment algorithm.AIM To determine patient preference for the treatment of trigger finger using an online survey.METHODS An online crowdsourcing platform,Amazon Mechanical Turk,was used to recruit participants for this study.Participants were led through a scenario in which they were diagnosed with trigger finger.They were then asked to rank their preference of treatment options from the following:Observation,splinting,corticosteroid injection,surgery.The results of the surveys were then analyzed using R software.RESULTS Of 323 participants completed the survey.7 participants were excluded because they failed to correctly answer the attention question,leaving 316 participants whose results were included.As a first choice for treatment 117(37%)of the included participants chose observation,86(27%)chose splinting,61(19%)chose corticosteroid injection,and 52(16%)chose surgery.The mean rank for observation was 2.26,for splinting was 2.30,for corticosteroid injection was 2.53,and for surgery was 2.91.The ranking of each treatment option was statistically different(P value<0.05)from the others except for observation and splinting.CONCLUSION The practice of shared decision making with patients is imperative to providing the best care possible.The results from this study,especially the preference for less invasive treatment,may help providers better frame discussion around treatment options of trigger fingers.This in turn,may increase patient satisfaction in the treatment of trigger finger.展开更多
This paper proposes a new method that reconstructs the information of specimen by using random phase shift step in digital holographic microscopy (DHM). The principles of the method are described and discussed in deta...This paper proposes a new method that reconstructs the information of specimen by using random phase shift step in digital holographic microscopy (DHM). The principles of the method are described and discussed in detail. In practical experiment, because the phase shifter is neither perfectly linear nor calibrated, digital holograms with inaccurate phase shift step are recorded by the charge-coupled device (CCD). The phase could be accurately reconstructed from the recorded digital holograms by using the random phase-shifting algorithm, which makes up for reconstructed phase error caused by ordinary phase-shifting algorithm. The phase aberration compensation is also discussed. In order to verify the flexibility of the proposed method, numerical simulation of random phase-shifting DHM was carried out. The simulation results illustrated that the presented method is effective when the phase shift step is unknown or random in DHM.展开更多
The correlation properties of the optical field diffusely reflected from a rough surface under coherent illumination are analyzed numerically. The cross-correlations of the complex amplitudes and the intensities befor...The correlation properties of the optical field diffusely reflected from a rough surface under coherent illumination are analyzed numerically. The cross-correlations of the complex amplitudes and the intensities before and after translation and/or tilt of the surface are calculated at an arbitrary observation plane in three-dimensional （3D） space. The results provide us with the 3D distributions of phase changes and speckle displacement that lead to the distributions measured by holographic interferometry and speckle relationships and physical interpretation of them are and signal-to-noise ratio of the displacement to be correlation technique. Comparisons with analytical also discussed.展开更多
文摘A phase-shifting digital holography scheme developed to investigate internal defects in artworks is described. Phase-shifting is utilized to obtain a clear reconstructed object wave from a rough surface texture. A reverse-transform algorithm is employed to reconstruct the object wave on its original position of unknown distance or the imaging position from the object wave information on the holographic plane. To get the clearest reconstruction the exact registration of the unknown distance is determined by applying the intensity sum as the auto-focusing function, The spatial resolution of the reconstruction image is also investigated for a variety of affecting factors. Laboratory results of reconstruction images under deformation are presented.
基金Supported by the Fundamental Research Funds for the Central Universitiesthe Funding for Outstanding Doctoral Dissertation in Nanjing University of Aeronautics and Astronautics(BCXJ11-01)~~
文摘An improved in-plane insensitive double-aperture digital speckle shearing interferometric technique is proposed to measure the first derivative of out-of-plane displacement （slope）. The temporal phase-shifting method is used for the quantitative analysis of fringes. The designed system employs a double-aperture arrange- ment placed in front of the imaging lens. A glass wedge covers one of the two apertures to introduce a laterally shear. The experimental specimen is a circular aluminum plate, clamped along its edge and subjected to both out- of-plane deflection and in-plane rotation. Experimental results show that the fringes obtained from the proposed optical configuration represent pure slope contour distributions, and that the contributions from the in-plane dis- placement components are completely eliminated. Theoretical and experimental results are in good agreement.
基金Project supported by the National Natural Sciences Foundation of China (No. 10572102).
文摘This paper deals with the mode I crack problem of a cracked rubber sheet under plane stress condition using the delicate digital moiré technique. Through the four step phaseshifting method of automated fringe analysis, the displacement fields in the Cartesian coordinate system are given. By the coordinate-transform equation, the radial and circular displacement distributions in the polar coordinate system are obtained. The displacement isoline distributions and displacement vector distributions near the crack tip are discussed. The strain isoline distributions near the crack tip are also analyzed in this paper. Finally, the distribution rules for the mechanical fields near the crack tip are discussed with the sector division method.
基金This work was supported by the National Key R&D Program of China(Nos.2023YFA1606403 and 2023YFE0101600)the National Natural Science Foundation of China(Nos.12027809,11961141003,U1967201,11875073 and 11875074).
文摘A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control parameters.The proposed digital system can be combined with a conventional analog data acquisition system to provide more flexibility.The performance of the combined system was veri-fied using experimental data.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61405130 and 61320106015)
文摘We present an optical encryption method of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography. By modifying the Mach-Zehnder interferometer, the interference of the multiple objects beams and the one reference beam is used to simultaneously encrypt multiple objects into a ciphertext. During decryption, each three-dimensional object can be decrypted independently without having to decrypt other objects. Since the single- pixel digital holography based on compressive sensing theory is introduced, the encrypted data of this method is effectively reduced. In addition, recording fewer encrypted data can greatly reduce the bandwidth of network transmission. Moreover, the compressive sensing essentially serves as a secret key that makes an intruder attack invalid, which means that the system is more secure than the conventional encryption method. Simulation results demonstrate the feasibility of the proposed method and show that the system has good security performance.
基金Supported by the Blue Cross Blue Shield of Michigan Foundation,No.22590764
文摘BACKGROUND Trigger digit is a common disorder of the hand associated with carpal tunnel syndrome.Carpal tunnel release(CTR)surgery may be a risk factor for trigger digit development;however,the association between surgical approach to CTR and postoperative trigger digit is equivocal.AIM To investigate patient risk factors for trigger digit development following either open carpal tunnel release(OCTR)or endoscopic carpal tunnel release(ECTR).METHODS This retrospective chart analysis evaluated 967 CTR procedures from 694 patients for the development of postoperative trigger digit.Patients were stratified according to the technique utilized for their CTR,either open or endoscopic.The development of postoperative trigger digit was evaluated at three time points:within 6 mo following CTR,between 6 mo and 12 mo following CTR,and after 12 mo following CTR.Firth’s penalized likelihood logistic regression was conducted to evaluate sociodemographic and patient comorbidities as potential independent risk factors for trigger digit.Secondary regression models were conducted within each surgical group to reveal any potential interaction effects between surgical approach and patient risk factors for the development of postoperative trigger digit.RESULTS A total of 47 hands developed postoperative trigger digit following 967 CTR procedures(4.9%).In total,64 digits experienced postoperative triggering.The long finger was most commonly affected.There was no significant difference between the open and endoscopic groups for trigger digit development at all three time points following CTR.Furthermore,there were no significant independent risk factors for postoperative trigger digit;however,within group analysis revealed a significant interaction effect between gender and surgical approach(P=0.008).Females were more likely to develop postoperative trigger digit than males after OCTR(OR=3.992),but were less likely to develop postoperative trigger digit than males after ECTR(OR=0.489).CONCLUSION Patient comorbidities do not influence the development of trigger digit following CTR.Markedly,gender differences for postoperative trigger digit may depend on surgical approach to CTR.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 51205136） , the Specialized Research Fund for the Doctoral Program of Higher Education of China （ Grant No. 20100172120003 ） and the Fundamental Research Funds for the Central Universities （Key Program） （ Grant No. 2013ZZ034）.
文摘Digital control system for pulsed MIG welding power based on STM32 is set up with 32-bit STM32FlO3ZET6 directing against the pulse waveform modulation of pulsed MIG welding. High-frequency inverter and medium-low frequency pulse waveform modulation of pulsed MIG welding are realized by using the integrated PWM module within STM32 to generate PWM signals of phase-shifted full-bridge soft-switching and constant-current control of output current is achieved by means of anti-windup PI control algorithm to improve the stability and reliability of control system. Experimental results demonstrate that the designed digital control system based on STM32 can achieve pegrect pulsed MIG welding technique with stable welding process and good weld appearance, fully demonstrating the advantages of digital control based on STM32.
文摘BACKGROUND Trigger finger is a common disorder of the hand that can cause disabling symptoms.Treatment options range from conservative management with observation and splinting,to surgical release,but there is currently not a consensus on a treatment algorithm.AIM To determine patient preference for the treatment of trigger finger using an online survey.METHODS An online crowdsourcing platform,Amazon Mechanical Turk,was used to recruit participants for this study.Participants were led through a scenario in which they were diagnosed with trigger finger.They were then asked to rank their preference of treatment options from the following:Observation,splinting,corticosteroid injection,surgery.The results of the surveys were then analyzed using R software.RESULTS Of 323 participants completed the survey.7 participants were excluded because they failed to correctly answer the attention question,leaving 316 participants whose results were included.As a first choice for treatment 117(37%)of the included participants chose observation,86(27%)chose splinting,61(19%)chose corticosteroid injection,and 52(16%)chose surgery.The mean rank for observation was 2.26,for splinting was 2.30,for corticosteroid injection was 2.53,and for surgery was 2.91.The ranking of each treatment option was statistically different(P value<0.05)from the others except for observation and splinting.CONCLUSION The practice of shared decision making with patients is imperative to providing the best care possible.The results from this study,especially the preference for less invasive treatment,may help providers better frame discussion around treatment options of trigger fingers.This in turn,may increase patient satisfaction in the treatment of trigger finger.
基金Supported by the National Basic Research Program of China("973"Project)(Grant No.2004CB619304)the National Natural Science Foundation of China(Grant Nos.10625209,10472050,10732080)+2 种基金the Project of Beijing Natural Sciences Foundation(Grant No.3072007)the Program for New Century Excellent Talents(NCET)in Chinese University Ministry of Education(Grant No.NCET-05-0059)the Opening Funds from the State Key Laboratory of Explosion Science and Technology
文摘This paper proposes a new method that reconstructs the information of specimen by using random phase shift step in digital holographic microscopy (DHM). The principles of the method are described and discussed in detail. In practical experiment, because the phase shifter is neither perfectly linear nor calibrated, digital holograms with inaccurate phase shift step are recorded by the charge-coupled device (CCD). The phase could be accurately reconstructed from the recorded digital holograms by using the random phase-shifting algorithm, which makes up for reconstructed phase error caused by ordinary phase-shifting algorithm. The phase aberration compensation is also discussed. In order to verify the flexibility of the proposed method, numerical simulation of random phase-shifting DHM was carried out. The simulation results illustrated that the presented method is effective when the phase shift step is unknown or random in DHM.
文摘The correlation properties of the optical field diffusely reflected from a rough surface under coherent illumination are analyzed numerically. The cross-correlations of the complex amplitudes and the intensities before and after translation and/or tilt of the surface are calculated at an arbitrary observation plane in three-dimensional （3D） space. The results provide us with the 3D distributions of phase changes and speckle displacement that lead to the distributions measured by holographic interferometry and speckle relationships and physical interpretation of them are and signal-to-noise ratio of the displacement to be correlation technique. Comparisons with analytical also discussed.
