Digital signal acquisition system for complex nuclear reaction experiments

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.

Phase-shifting digital holography in image reconstruction

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.

IN-PLANE INSENSITIVE DOUBLE-APERTURE DIGITAL SHEAROGRAPHY FOR SLOPE MEASUREMENT

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.

APPLICATION OF THE DIGITAL MOIRE METHOD IN FRACTURE ANALYSIS OF A CRACKED RUBBER SHEET

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.

Optical encryption of multiple three-dimensional objects based on multiple interferences and single-pixel digital holography

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.

Factors associated with trigger digit following carpal tunnel release

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.

Digital control system for pulsed MIG welding power based on STM32

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.

Patient preference for trigger finger treatment

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.

按键式密码电子锁电路的设计

数字电路的设计在计算机、电子和自动化等专业中占据着非常重要的地位,另一方面,现代的教育理念要求加强对学生分析能力、实践动手能力和创新应用能力的培养。为了更好地将理论知识与实践结合起来,详细地阐述了利用集成芯片和门电路设计生活中常见的电子密码锁设计过程,包括核心器件触发器的选择、通过几种方案的比较确定最优设计方案、密码锁的工作过程及相关电路的设计。通过实验室实验验证,增强了学生对电路的感性认识,提高了学生的学习兴趣与效率。

A novel random phase-shifting digital holographic microscopy method

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.

Holography and speckle in phase-shifting digital holography(Invited Paper)

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.

数字存储示波器触发电路的数字化技术研究

提出了一种全数字化的数字存储示波器用的触发电路结构。采用先进先出存储器 FIFO,利用其存储数据先进先出的特性 ,结合高速数字比较器的比较特性 ,控制采样数据的存储 ,从而实现触发电路的多种功能。给出了数字触发电路原理框图以及在 CPL D上的设计实现 。

用于激光打靶装置中的新型同步系统的研究

一种用于多路激光打靶装置中的新型智能化数字同步机已经研制成功 ,它将模拟延时电路和数字延时电路巧妙结合在一起 ,使得最大延时范围达到 1 s,触发晃动小于 1 ns,步进精度 5

交流电动机软起动与节能控制中的数字触发系统

提出了一种三相晶闸管交流调压的数字移相控制方法 ,分析和讨论了该方法的工作和设计原理 ,研制了采用 80C196KC单片机和GAL16V8可编程器件构成的数字移相触发系统 。

基于DSP控制的十二相焊接电源主电路数字化触发

数字化焊接电源已经成为新型焊接电源的发展趋势,采用由数字信号处理器(DSP)作为控制核心对新型十二相晶闸管CO2气体保护焊接电源的主电路功率器件进行数字化触发。实验证明,通过DSP软件编程产生触发信号可靠稳定,实现了晶闸管的数字化触发。

基于PC的个人逻辑分析仪设计

随着数字系统和计算技术的发展 ,逻辑分析仪在高速硬件逻辑测试和软件状态分析中显得尤其重要。由于目前台式逻辑分析仪的价格比较昂贵 ,使得它不能普遍应用于教学和科研实践中。本文介绍一种基于 PC机增强型并行口的个人逻辑分析仪设计技术。该技术充分利用 PC机的丰富资源 ,通过增强型并行口 ,采用现场可编程门阵列的在系统可重构技术和面向对象的软件设计方法 ,实现数字域的逻辑分析功能 ,其特点灵活、便携。此仪器可广泛应用于电子对抗、雷达。

手持数字示波表技术研究

手持数字示波表是数字存储示波器的一个分支 ,在工业现场得到广泛应用。现介绍一种基于双路 10 0 MSPS高速数据采集系统的手持示波表实现方案。文中重点讨论了其中的关键技术 ,包括 2 0 0 MSPS高速数据采集的实现、FPGA内部实现数字触发电路、液晶显示控制电路和显示数据同步电路、采集控制和存储电路。

以数字信号为基控制的可控硅焊机的数字触发

用PROTEL99-SIM仿真软件分析了可控硅焊机单结晶体管 (UJT)移相触发电路受温度变化的影响 ,仿真结果表明 ,单结晶体管移相触发电路温漂对触发脉冲移相时间的影响较大 ,从而影响焊接参数输出的稳定性。另外 ,数字化焊接电源已成为焊接电源的发展趋势 ,这其中要求焊机的数字化触发。针对以上问题本文研究通过高集成度数字信号处理芯片 (DSPs)软件编程产生可控硅整流焊机主电路的触发信号。试验证明 ,通过软件编程DSPs产生的触发信号可靠稳定 ,软件简单明了 ,使原来复杂的移相触发电路变成移相触发软件的编程 ,为焊机的数字化、信息化控制打下了基础。

基于单计数器控制采集存储的虚拟示波器的设计

本文开发虚拟数字存储示波器按照数字示波器原理设计信号调理电路和逻辑控制电路等硬件电路,并改进了数字示波器运用前置计数器和后置计数器控制触发点前后的采集样点数的方案,运用一个计数器实现了触发点前后的采集样点数的控制。虚拟数字存储示波器操作的界面,功能选择,参数测量和显示等功能运用虚拟仪器原理开发。开发的SJ-8002B虚拟数字示波器虚实结合,充分体现数字示波器的性能优势,很好地利用计算机的处理能力,运行稳定,节约资源,有利于研制和生产深度存储的数字示波器。

考试系统中成绩安全性多级管理模式研究

基于C/S模式的考试系统,成绩一般都存储在各个考点的数据库中,这样数据库的成绩存在着许多的安全问题,如成绩易被修政、复制。通过分析,提出考试系统成绩的安全性管理的多级管理模式,每一级均起到一定的保护作用。多级的结合,使得考试系统的成绩有了一定的安全保障。该方案在实际考试系统运行过程中收到良好的效果。