Comparison of Two Electronic Root Canal Length Measurement Devices: The Differences between Ratio Two Impedance Frequencies and Multi Frequencies

Accuracy electronic root canal length measurement devices were important for root canal treatment. Aim: To evaluate and compare accuracy of the two electronic root canal length measurement devices;two frequencies impedance ratio and multi frequencies. Methods: Forty anterior teeth were sectioned on their cervical area. All samples were measured root canal length by radiographic. On the second phase, all the samples were measured by two frequencies impedance ratio and multi frequencies electronic devices. In the final phase, the teeth were split vertically and actual lengths were measured. All measurement by radiographic and electronic method was subtracted with actual length. Statistical analysis was performed using Chi-square and the Kolmogorov-Smirnov test. Results: Accuracy of the two frequencies impedance ratio 50% and multi frequencies 47.5%. No statistical significance between two frequencies impedance ratio and multi frequencies. Conclusions: There is no difference between ratio two impedance frequencies and multi frequencies.

The Research and Application of the Anti-Interference Techniques of Electronic Device in Power System

This paper presents the study and application of the electronic device anti-interference techniques underhigh voltage and/or heavy current electro-magnetic circumstance in power system.[

Experimental Research of Electronic Devices Thermal Control Using Metallic Phase Change Materials

A Phase-change thermal control unit( PTCU) filled with metallic phase change material( PCM) Bismuth alloy for electric devices thermal protection was developed and investigated experimentally. The PTCU filled with PCM was designed and manufactured. Resistance heating components( RCHs) produced 1 W,3 W, 5 W,7W,and 10 W for simulating heat generation of electronic devices. At various heating power levels,the performance of PTCU were tested during heating period and one duty cycle period. The experimental results show that the PTCU delays RCH reaching the maximum operating temperature. Also,a numerical model was developed to enable interpretation of experimental results and to perform parametric studies. The results confirmed that the PTCU is suitable for electric devices thermal control.

Corrosion in Control Systems Decrease the Lifetime of the Electronic Devices of the Industrial Plants of Mexicali,BC,Mexico

The principal factor to determine the economical value of the products manufactured in the electronics industry is due to the productive yielding. This is important for the cost of the articles fabricated in this type of industrial plants installed in Mexicali city, where around 80% of companies are, and which fabricate electronic devices and systems, or have industrial electronic systems and machines to their manufacturing process. Mexicalicity is located in theBaja CaliforniaStateof the northwest ofMexico, which is a border city with Calexico in theCaliforniaStateof the United States of America (USA). The region located in Mexicali, is a desert area. Geothermal plant is located in this area, which is an important industry and supplies electricity to this city and its valleys and some cities on southwest of United States for daily activities. This company emits hydrogen sulfide (H2S) as a main air pollutant that reacts with oxygen in the atmosphere, generating sulfur oxides (SOX). This chemical is dispersed to the city of Mexicali in which industrial plants are located with electronic control systems, and penetrates to indoor rooms. Those cause the corrosion process. The presence of corrosion leads to the deterioration of electrical connectors, the connections of electronic systems and the decreasing of the lifetime of these control systems. Other air pollutants that are considered as chemical agents which cause damage to materials used in the electronics industry, are the sulfurs and nitrogen oxides (NOX), emitted from the traffic vehicle and some industries. This causes the low productive yielding of electrical and electronic devices and systems used in the companies of this city, and is a major concern to specialized people, managers and owners. To analyze the productive yielding of electronic devices and systems installed in indoor of the electronics industry. For this reason, to know the principal causes of it, a study in three industrial plants, to determine the grade level of deterioration of the electronic control systems (ECS) used in the electronics industry of this city was made. The results showed that at major air pollution concentration detected by specialized methods, the lifetime of the ECS was decreased by the generation of corrosion in their electrical connectors and connections. This was caused for the levels of air pollutants mentioned above, than exceed the air quality standards in some periods of the year, added with the levels upper of relative humidity levels (RH) and temperatures of 85% and 25°C in winter and 80% 35°C in summer, being a main factor of this electrochemical phenomenon.

Evaluation of the systematic set-up errors using electronic portal image device in the radiotherapy procedures

Objective： The aim of this work was to quantify the extent of set-up errors to conduct a quality assurance （QA） aspect of treatment delivery, verification of the treatment field＇s position on different days using electronic portal. Methods： This study was carried out on 12 patients, treated for pelvis tumor; and total of 240 images obtained by electronic portal image device （EPID） were analyzed. The EPIs acquire using EPID attached to the Siemens linear accelerator. The anatomy match- ing software （Theraview） was used and displacement in two dimensions were noted for each treatment field to study patient setup errors. Results： The percentages of mean deviations less than 5 mm in X direction were 65% ＆ 92%, from 5-10 mm were 31% ＆ 19% and more than 10 mm were 11% ＆ 9% forNP and lateral direction respectively. The percentages of mean deviations less than 5 mm in Y direction were 65% ＆ 63%, from 5-10 mm were 33% ＆ 28% and more than 10 mm were 22% ＆ 29%. The mean deviations in 2D-vector errors were 〈 5 mm in 47% and 46%, 5-10 mm in 36% and 37% and 〉 10 mm in 37% and 37% of images in the NP and lateral direction respectively. Conclusion： The results revealed that the ranges of set up errors are immobilization method to improve reproducibility. The observed variations were not within the limits..

DeviceNet现场总线与对称分量法在电动机保护测控装置中的应用

基于DeviceNet现场总线与对称分量法,研制了集保护、报警、测量、控制与DeviceNet通信等多项功能于一体的电动机综合保护测控装置。深入研究了DeviceNet的通信机理,提出了该装置DeviceNet通信的实现方法,构建了针对该装置的对象模型和设备描述。针对对称分量法实际应用中两种系统接地方式均采用同一滤序计算公式的问题进行了分析和讨论,给出了分别适用于大电流、小电流接地系统的滤序计算公式。

An Automatic Synchronization Method for Distributed Power Electronics System

Currently, the high-speed serial fiber-optic ring net communication is a main method for performing the distributed control network topology and control mode. Because of a network transmission delay inherent in the topology, synchronization between nodes has become a critical issue which needs to be studied. The existing synchronization methods largely depend on the complex communication protocol. Therefore, this paper has proposed a method of automatic measurement and compensation of synchronization delay, and analyzed its operating principle and implementation procedure in detail. The results obtained from the experiments prove the proposed method to be correct, effective and practicable.

High signal-to-noise ratio sensing with Shack–Hartmann wavefront sensor based on auto gain control of electron multiplying CCD

High signal-to-noise ratio can be achieved with the electron multiplying charge-coupled-device（EMCCD） applied in the Shack–Hartmann wavefront sensor（S–H WFS） in adaptive optics（AO）.However,when the brightness of the target changes in a large scale,the fixed electron multiplying（EM） gain will not be suited to the sensing limitation.Therefore an auto-gain-control method based on the brightness of light-spots array in S–H WFS is proposed in this paper.The control value is the average of the maximum signals of every light spot in an array,which has been demonstrated to be kept stable even under the influence of some noise and turbulence,and sensitive enough to the change of target brightness.A goal value is needed in the control process and it is predetermined based on the characters of EMCCD.Simulations and experiments have demonstrated that this auto-gain-control method is valid and robust,the sensing SNR reaches the maximum for the corresponding signal level,and especially is greatly improved for those dim targets from 6 to 4 magnitude in the visual band.

密封电子元器件与装置多余物检测发展综述

密封电子元器件与装置作为航天系统中的重要组成部分,具有高精密性、高可靠性以及高复杂性的典型特点,而多余物问题是严重影响其高可靠性的主要因素之一。随着航天技术的快速发展,多余物检测技术也在不断改进与深入。该文以认识多余物、控制多余物产生以及检测多余物为主线,围绕多余物的防控方法、检测方法、检测标准进行综合论述。着重分析了检测方法中的颗粒碰撞噪声检测(PIND)方法,分别从小型元器件多余物检测、中大型装置多余物检测两个角度,针对现有研究进展逐一进行了详细的介绍。在此基础上,结合现有国内多余物检测研究的现状,针对多余物检测的难点与未来发展趋势进行归纳,并提出了期望与目标。

“光储直柔”建筑配电系统应用研究

以某项目为例分析“光储直柔”在建筑物中的应用,并对“光储直柔”系统的应用场景、建筑直流配电系统的关注点及“光储直柔”系统关键设备进行阐述。

基于蒙特卡洛仿真的航空用测控装置可靠性预计

文章研究了某面向航空应用的高可靠性测控装置的可靠性预计问题。根据测控装置设计原理图建立了可靠性框图,基于GJB/Z299C手册和应力分析法得到了元器件可靠性数据,建立了基于蒙特卡洛仿真方法的系统可靠性预计数学模型,预计了测控装置的可靠性指标,并通过分析查找可靠性薄弱环节,改进了设计方案,提高了可靠性,最终达到设计要求。文章研究表明,蒙特卡洛仿真方法对于混连复杂电子系统的可靠性预计具有较好的实用性。

智能配电控制系统的设计思路

鉴于电力行业日新月异的发展变化,传统的配电控制架构已难以适应现代电网日益增长的复杂形势。因此,智能配电控制系统的诞生尤为必要。文章深入探讨了智能配电控制系统的设计思路,在系统通信方案上,采用先进的EPON光纤通信技术,以确保数据传输的高效和稳定。同时,系统也支持其他多种通信方式接入,如GPRS通信、图像传输等,以适应不同场景的需求。此外,系统还兼容RS485、Canbus等现场总线标准,方便智能传感器的接入和扩展。对于需要更高带宽和稳定性的应用,系统还支持以太网接入技术,以满足更加复杂和多样化的网络通信需求。

Optimized Axillary Vein Technique versus Subclavian Vein Technique in Cardiovascular Implantable Electronic Device Implantation： A Randomized Controlled Study

Background：The conventional venous access for cardiovascular implantable electronic device （CIED） is the subclavian vein,which is often accompanied by high complication rate.The aim of this study was to assess the efficacy and safety of optimized axillary vein technique.Methods：A total of 247 patients undergoing CIED implantation were included and assigned to the axillary vein group or the subclavian vein group randomly.Success rate of puncture and complications in the perioperative period and follow-ups were recorded.Results：The overall success rate （95.7% vs.96.0%） and one-time success rate （68.4% vs.66.1%） of punctures were similar between the two groups.In the subclavian vein group,pneumothorax occurred in three patients.The subclavian gaps of three patients were too tight to allow operation of the electrode lead.In contrast,there were no puncture-associated complications in the axillary vein group.In the patient follow-ups,two patients in the subclavian vein group had subclavian crush syndrome and both of them received lead replacement.The incidence of complications during the perioperative period and follow-ups of the axillary vein group and the subclavian vein group was 1.6% （2/125） and 8.2% （10/122）,respectively （χ^2=5.813,P =0.016）.Conclusion：Optimized axillary vein technique may be superior to the conventional subclavian vein technique for CIED lead placement.

输电网中储能电站的智能预测系统设计

针对输电网中风电场与储能电站的容量配置问题,设计了一种输电网中储能电站的智能预测系统。采用直流系统、站用电低压系统、监控系统、微机保护装置、测控装置、计量装置、人工智能、5G移动通信以及综合自动化设备,创建智能预测系统。通过基于混合蛙跳算法(SFLA)的人工智能,实现储能电站容量的计算、研究、预测,同时对储能电站进行优化配置。将外连接口与卡线器进行对接。通过传感设备采集检测单元需要的硬件信息、运行状态、设备情况和额定负载等数据,并对数据进行优化。试验结果表明,该系统在储能电站的预测精准度高达90%以上。该系统对解决电能浪费问题具有较强的实用性,也符合储能电站的特性。

基于电子射野影像系统的光栅位置和剂量验证研究

目的 使用基于电子射野影像系统(electronic portal imaging device,EPID)的质控系统,在Primus和VenusX加速器上实现光栅位置及剂量验证。方法 通过灰度值最大梯度方法计算光栅位置,评估偏差。使用剂量标定和剂量计算相结合的算法对EPID采集的图像进行剂量重建,将EPID和MapCheck/PTW得到的数据,分别与计划系统剂量进行γ通过率分析。结果 VenusX加速器光栅误差小于1 mm,Primus重新标定后误差明显减小。重建的剂量,在3%/3 mm,阈值10%和2%/2 mm,阈值10%的2种标准下,Primus加速器γ平均通过率分别为98.86%和91.39%;VenusX加速器γ平均通过率分别为98.49%和91.11%。结论 基于EPID的质控系统,可提高加速器质控效率,减轻物理师工作负担。

基于可穿戴电子设备干预对健康青少年身体活动和久坐行为影响的Meta分析

目的:虽然可穿戴电子设备作为干预工具在增进身体活动方面展现出潜在效用,但关于其对健康青少年群体具体效果的全面评估仍显不足。为此,文章系统地探索和总结基于可穿戴电子设备的干预对健康青少年身体活动及久坐行为的影响,以期为公共卫生实践提供更精准和可靠的循证支持。方法:从Web of Science,PubMed,Scopus,The Cochrane Library和EBSCO数据库中检索关于可穿戴电子设备的干预对健康青少年身体活动和久坐行为影响的随机对照试验。利用RevMan 5.4和Stata 17软件进行Meta分析,通过标准化均数差评价干预对身体活动及久坐行为的效果。为确保研究结果的稳健性,采用Leave-One-Out方法进行敏感性分析,并通过亚组分析深入探究不同因素对结果的可能影响。该方案已在国际系统综述前瞻性注册中心注册(CRD42023406645)。结果:①最终纳入12篇文献,其中包含3项随机对照试验和9项整群随机对照试验,共纳入4933名健康青少年对象。②Meta分析结果发现,基于可穿戴电子设备的干预对中高强度身体活动产生了积极影响(SMD=0.10,95%CI:0.04-0.17;P<0.05),然而,该干预未能显著改善低强度身体活动(SMD=-0.15,95%CI:-0.32-0.02;P>0.05)、每日步数(SMD=0.13,95%CI:-0.65-0.91;P>0.05)和久坐行为(SMD=0.00,95%CI:-0.09-0.09;P>0.05)。③亚组分析结果表明,短期(≤12周)干预(SMD=0.11,95%CI:0.03-0.18;P=0.008)、佩戴在腰或臀部的计步器的研究(SMD=0.10,95%CI:0.04-0.17;P=0.002),以及在临床注册中心注册的试验(SMD=0.11,95%CI:0.04-0.17;P=0.001)对提升每日中高强度身体活动的效果更为显著。结论:当前证据表明,基于可穿戴电子设备的干预措施在提升健康青少年每日中高强度身体活动方面具有一定优势;建议通过不超过12周的干预时间、使用腰部或臀部计步器的干预设备以获得更好的促进效果;然而,每日步数、低强度身体活动以及久坐行为的干预效果存在一定的局限性,未来仍需要更高质量、大样本的随机对照试验进一步验证。

EPID在加速器光射野一致性检测中的应用

目的比较慢感光胶片和电子射野影像装置(Electronic Portal Imaging Device,EPID)在检测加速器光射野一致性中的差异,以探索出一种准确、高效、经济的加速器光射野一致性检测方法。方法在每周的加速器质控过程中,分别使用慢感光胶片和EPID来检测Synergy医用电子直线加速器的6 MV X射线在射野为10 cm×10 cm时的光射野一致性;连续检测20周后,统计分析2种工具在检测加速器光射野一致性中的差异。结果Synergy加速器的6MV X射线在射野为10 cm×10cm时,采用慢感光胶片和EPID在X1、X2、Y1和Y2共4个方向上检测光射野一致性的结果均符合NCC/T-RT001-2019《医用电子直线加速器质量控制指南》所规定的性能要求。其中,在X1方向上,慢感光胶片和EPID2种工具检测的光射野一致性差异分别为(0.29±0.40)、(0.16±0.41)mm;在X2方向上,慢感光胶片和EPID2种工具检测的光射野一致性差异分别为(-0.04±0.30)、(-0.14±0.38)mm;在Y1方向上,慢感光胶片和EPID2种工具检测的光射野一致性差异分别为(0.13±0.32)、(0.26±0.35)mm;在Y2方向上,慢感光胶片和EPID2种工具检测的光射野一致性差异分别为(-0.20±0.33)、(-0.18±0.34)mm。在X1、X2、Y1和Y2共4个方向上,慢感光胶片和EPID之间检测的光射野一致性差异均无统计学差异(P>0.05)。结论与慢感光胶片相比,EPID在加速器的光射野一致性检测中具有较好的一致性,且具有准确、高效、经济的特点,可用于加速器光射野一致性的检测。

拖拉机后悬挂电液控制系统的研究

传统拖拉机在进行农田作业时主要依靠手动控制耕作深度等技术参数,导致耕作误差较大。针对以上问题,研发了一种三点式双作用拖拉机液压悬挂系统,基于双PID控制算法对关键电路部件与控制方案进行设计与选型,并基于MatLab分析拖拉机后悬挂电液控制技术的工作特性。田间试验结果表明:设计的拖拉机后悬挂电液控制系统可以满足田间农业生产要求。

浙江省医疗器械临床试验机构备案现状分析

自2018年起,医疗器械临床试验机构由资质认定改为备案管理。本文通过查询国家药品监督管理局网站:医疗器械临床试验机构备案管理信息系统平台,对2018年1月1日至2023年9月30日浙江省备案的医疗器械临床试验机构进行多维度统计分析。主要研究内容包括浙江省医疗器械临床试验机构的数量、医院等级、地区分布、备案专业、研究者备案情况等。通过分析可以看到目前浙江省医疗器械临床试验机构还存在着全省备案机构分布不均匀、机构管理水平有待提高、临床试验团队专职人员配备不到位、临床试验研究团队人员培训不足等问题。本文建议省内各医疗器械临床试验机构保障基础配置,配备专职管理人员;健全人才培训,提高研究者临床试验水平;制定激励措施,调动研究者积极性;强化风险意识,紧抓全链条质量控制;加强交流合作,完善临床研究应用,不断提升省内各医疗器械临床试验机构实力,以期提高浙江省医疗器械临床试验水平,促进医疗器械行业高质量发展。

液压挖掘机液能回收再利用节能装置测控系统

液压挖掘机动臂下降重力势能和回转制动动能均以节流和溢流的形式转化为了油液的热能,严重影响整机能效,亟需提高液压挖掘机液压系统的效率。针对这一问题,提出了基于三腔蓄能器的挖掘机液能回收再利用的节能装置方案,可以回收挖掘机动臂势能和回转制动动能,用于驱动动臂举升。首先,介绍了节能装置的工作原理。其次,设计并开发了节能装置的测控系统,采用CoDeSys编写了下位机控制器程序,直接控制节能装置的动作实现能量回收和再利用;运用C#语言开发了上位机程序进行节能装置电控系统和液压系统的模拟调试和数据监控,并实现了节能装置的远程无线通讯功能。试验结果表明:该测控系统实现了对插装阀开闭和比例节流阀开度的快速、精准控制;达到了对节能装置远程控制和数据实时采集的目标;节能装置的动臂势能回收效率为84.9%,动臂节能效率为52.8%,回转制动工况下的动能回收效率为41.1%。