基于单片机的数字电压表设计

本文设计了串联线性稳压电源及基于单片机LED数码管数字显示电路,提供了原理电路及PCB版图,分析了软件设计思路及主函数流程图,说明了装配及调试主要事项。     

智能金属丝微小形变量的测量仪

设计制作一种智能化金属丝微小形变量测量仪,利用胡克定律及惠斯登电桥原理,采用压力传感器产生力电信号,经过A/D转换电路转换成数字信号送入到单机片中,完成后显示在LCD12864显示屏上。因为被测量的弹性模量在不同温度下的数值不同,该装置可以测量压力、形变量、实时温度的显示功能。     

可燃气体报警器在化工装置上的应用

因为石油本身特性,石油化工炼制过程中必然产生可燃气体,而可燃气体的泄露则会对装置及职工人身安全造成极大隐患。因此,可燃气体检测日益受到重视。文章针对某化工装置可燃气体报警器的更新改造,解析了新旧两种可燃气体报警器的异同,并详细介绍了可燃气体报警器安装注意事项及化工装置应用所独有的特点,为可燃气体报警器的选用安装及维护提供参考。     

基于单片机的数字直流电压表的设计与实现

数字直流电压变在工程中应用比较广泛,而单片机价格便宜且在数字电表开发与应用方面表现突出。鉴于此,本文基于单片机设计一款数字直流电压表。     

重量定量法自动调胶控制系统设计

重量定量法自动调胶控制系统采用应变片为称重传感器,当注入容器中原料的重量作用于称重传感器时,使惠斯登电桥失去平衡而输出电信号。各设定重量下输出的电信号经放大后,触发强电控制电路中按信号强弱顺序设置阀值的晶闸管,使外电路中的交流接触器依次动作并启动各原料进料装置,依次向调胶容器中注入胶、水、添加剂等原料。该自动调胶系统经调试设定后,可按要求自动实现定量下料、定时搅拌、定时出料等顺序控制,与容积定量调胶法相比,具有自动化程度高、精度高、效率高等特点。     

重量定量法自动调胶控制系统设计北大核心

重量定量法自动调胶控制系统采用应变片为称重传感器,当注入容器中原料的重量作用于称重传感器时,使惠斯登电桥失去平衡而输出电信号。各设定重量下输出的电信号经放大后,触发强电控制电路中按信号强弱顺序设置阀值的晶闸管,使外电路中的交流接触器依次动作并启动各原料进料装置,依次向调胶容器中注入胶、水、添加剂等原料。该自动调胶系统经调试设定后,可按要求自动实现定量下料、定时搅拌、定时出料等顺序控制,与容积定量调胶法相比,具有自动化程度高、精度高、效率高等特点。     

用数字印刷投资未来

<正>当印刷工业成本压力、印量减少、产能过剩以及商品化等特性愈发明显之时,数字印刷也许是唯一的出路。目前,数字印刷作为新的印刷组成部分,已经占据了全球印刷市场生产量的5%～10%,而且还在不断增速扩张,越     

如何更有效地用好数字打样系统

数字打样技术凭借其快捷的速度、稳定的质量、低廉的成本,迅速在广告设计、输出、印刷及相关企业内普及开来。使用一段时间后,有的企业充分享受到新技术带来的优势,在工作效率、客户满意度、成本控制方面都收到了较好的效益。 中华商务、雅昌彩印、运城制版等企业,充分体会到数字技术的进步为 他们带来好处,在短短的两年中,采购了数十套数字打样系统。但也 有部分企业在使用数字打样时却不尽如人意,甚至废弃不用。为什么呢?让我们来分析一下数字打样系统和其它产品的不同点。 很多人认为,购买数字打样系统不就是花几万块买来,让供…     

数字时代文献保护技术实验项目整合与创新

文献保护技术是档案学专业的一门综合型应用课程,具有很强的实践性、跨学科性、技术性与创新性,数字时代的到来给文献保护技术实验项目的建设与教学带来了冲击与挑战。文章提出整合文献保护技术实验的传统特色项目,创新数字时代文献保护新型实验项目,设计数字时代文献保护技术实验项目体系。在整合与创新的实现路径中,需创新文献保护观、整合更新仪器设备和推进文献保护的产学研融合,为文献保护技术实验项目注入源动力。     

2D数字伺服阀的特性实验研究

采用位置跟踪和电流反馈的双闭环控制下,对2D数字伺服阀的动静态特性进行实验研究。动态工作下,阀的阶跃响应时间最快可达到6 ms,在输入信号的幅值对应为阀最大开口的25%下,幅频特性为-3 dB对应的频宽约为65Hz,静态状态下,阀芯转角输入与轴向位移输出基本成线性。实验结果表明,2D数字伺服阀具有良好的线性度和对数频率特性。     

Body condition assessment using digital images

This project assessed the ability to assign a body condition score (BCS) to a dairy cow from digital photographs or videos. Images were taken from the rear of the cow at a 0 to 20° angle relative to the tail head. Four observers assigned a BCS to each of 57 cows at a farm visit (live, farm 1) and later from a photograph (photo). Means ± standard deviations of BCS by method and observer were as follows: live = 3.25 ± 0.51, 3.42 ± 0.49, 3.32 ± 0.58, 3.13 ± 0.62; photo = 3.36 ± 0.52, 3.32 ± 0.43, 3.44 ± 0.62, 3.14 ± 0.6 for observers 1 to 4, respectively. Body condition score means differed across observers for live (observer 2 higher and observer 4 lower, compared with observers 1 and 3) and photo methods (observer 3 lower, compared with observers 1, 2, and 3); however, within observer, the mean live BCS did not differ from the mean photo BCS. Correlation coefficients between BCS assigned live and from photos were 0.84, 0.82, 0.82, and 0.90 for observers 1 to 4, respectively. Subsequently, observer 1 visited 2 farms, assigned a live BCS, and digitally photographed 187 cows (56 and 131 cows from farms 2 and 3, respectively). Observers 2, 3, and 4 assigned a BCS from the photographs. Means ± standard deviations of BCS by observer (method) were 1 (live) 3.35 ± 0.55; 2 (photo) 3.33 ± 0.49; 3 (photo) 3.60 ± 0.54; and 4 (photo) 3.26 ± 0.62. The mean BCS for observer 3 was higher and that for observer 4 was lower than for observers 1 and 2. Correlation coefficients between observer 1 and observers 2 through 4 were 0.78, 0.76, and 0.79, respectively. Observer 1 assigned a BCS to 41 cows at a farm visit and 3 wk later assessed the BCS of cows from a video taken at a farm visit by a different individual. Cows were restrained in headlocks at a feed bunk when assessing BCS and for video production. No difference was detected for the mean BCS, for the standard deviation of the mean BCS, or in the distribution of BCS between the live and video assessments. Mean and SD for 17 groups of Holstein cows from 20 farms were used to generate 10,000 random samples of BCS. Groups of 25, 50, 100, and 150 cows were created from the random samples, and estimates of mean BCS were determined by sampling 3 to 80% of the group. Estimates of mean BCS with a sample size of 30% or more from a group of cows fell within the 95% confidence limit of the true mean more than 98% of the time. Digital photographs provide adequate imaging for assessment of BCS. Sampling 30% of a group should be adequate to assess the mean BCS. Video imaging allowed a rapid assessment of BCS but did not permit identification of individual cows.     

Yarn twist measurement using digital imaging

Digital image analysis techniques in the spatial and frequency domains for twist measurement of yarns are described. A spatial technique is developed to extract the twist angle through the analysis of the yarn core image. Then, a Fourier transformation technique is applied to yarn images to measure the orientation of the fibre on the yarn surface. Finally, a hybrid method that incorporates frequency domain filtering prior to spatial analysis is proposed. The trials show that spatial analysis is a fast method and can successfully predict the twist in the yarn. Fourier transformation technique is quite sensitive to the protruding fibres obstructing the yarn surface, which may result in measurements having high variations. For yarns having little amount of hairs protruding from the core, the results agreed reasonably well with actual twist levels. Frequency domain filtering in conjunction with the spatial analysis of the yarn surface is found to be superior in terms of accuracy. The twist values calculated using the more reliable diameter measurements with back-lit images together with twist angles from the front-lit images are found to be more accurate when compared with the actual values.     

数码相机在染色织物色差测量中的应用

针对目前颜色及色差测量设备单一、价格昂贵等问题,对应用数码相机进行织物色差的预测的可行性进行了研究。首先通过自制图像采集系统对样本图像进行采集;然后从RAW格式图像中提取原始的RGB响应信息;最后建立原始传感器三通道响应信息和CIE L*a*b*值之间的非线性回归模型实现样本颜色的测量,并对织物色差进行预测。480张色卡样本的实验结果表明：所构建的非线性回归模型参数数量并非越多越好,其有效度依赖于所选择的特定参数。回归模型应用于纺织品CNCS色卡和染色样布的色差测量结果表明：所得平均色差差值分别为1.16和1.34,接近于DigiEye测色结果,且能与其保持良好的一致性,说明此方法在织物色差预测与评价中有较好的可行性和实用价值。     

Prevalence of digital dermatitis using mirror scoring in Finnish freestall dairy herds

Digital dermatitis (DD) is a severe bacterial hoof disease found worldwide. The disease can be classified into 5 different stages, denoted as M1 to M4 and M4.1, by clinical examination. The main objective of this study was to estimate prevalence of DD lesions in Finnish freestall dairy cattle population through hind feet inspection of standing cows with a mirror. Another aim was to estimate the sensitivity and specificity of mirror scoring on standing cows in a pen or in a milking parlor without washing the feet. Three veterinarians visited 81 randomly selected herds across the country. During the herd visits, hind feet of standing cows (n = 7,010) were scored with a mirror without washing the feet, either when the cows were standing in a pen (n = 4,992) or in the milking parlor (n = 2018). In total, 128 cows (111 from pen and 17 from milking parlor) including 256 feet were chosen with cross-sectional sampling and scored in a trimming chute. Animal-level sensitivity for scoring M2 lesions with a mirror was 55% and specificity was 97%; for all active DD lesions (M1, M2, or M4.1), sensitivity was 36% and specificity was 96%. Sensitivity for scoring any DD lesions was 90% and specificity was 82%. The bias-corrected sensitivity and specificity for scoring any DD lesions were 79% and 92%, respectively. The bias-corrected sensitivity and specificity for scoring M2 DD lesions were 10% and 100%. We found M2 lesions in 12.1% of the study herds, and true herd-level prevalence was the same. Altogether, 33.3% (true prevalence 28.4%) of the herds had either M1, M2, or M4.1 DD lesions. However, only 0.7% (true prevalence 5.4%) of cows in total had active M2 lesions. The within-herd prevalence of M2 lesions (in herds where at least 1 cow had a M2 lesion) was 5.7% and varied between 0.4% and 18.8%. Herds with active DD lesions also had more any DD lesions than herds without active DD lesions. The herd-level prevalence was higher than previously thought, with only 1 herd without any DD lesions. However, the animal-level prevalence of active DD lesions was relatively low. Farmers and veterinarians need to be informed of the disease and possible control measures. Because of the low within-herd prevalence, the control of the disease might be easier than in countries where DD is widespread. Further studies are needed to identify factors associated with DD prevalence in Finnish dairy herds.     

应用纱线序列图像的电子织物构建

为检测纱线条干均匀性对织物外观的影响,在纱线条干图像测量的基础上,提出了一种基于纱线序列图像的电子织物的构建方法。通过建立织物组织变化模型和光照模型,将纱线直径值与基元组织点外观灰度纹理分布相结合,构建电子织物外观数学模型。实验中通过将采集的纱线序列图像进行图像分割和形态学运算等处理,获取纱线直径数据,代入到构建的织物外观数学模型中,实现基于纱线序列图像的电子织物的模拟并且相关参数可调。通过选择合理的织物结构参数,提出的电子织物模型能够真实的反映纱线条干均匀性对织物外观的影响,准确预测布面效果。     

数字PCR在食源性致病微生物检测中的 应用研究进展

大多数食源性疾病由食源性致病微生物引发,研究和建立食源性致病微生物的快速有效检测方法对于食品安全风险监控及保障人们的身体健康具有重要意义。相对于传统PCR,数字PCR具有较好的准确度和重现性,可实现绝对定量分析,为快速准确地进行食品安全检测提供了一种崭新的技术平台。本文主要介绍了数字PCR中微滴式数字PCR和芯片式数字PCR的基本原理、种类、应用及其研究进展,深入探讨了数字PCR技术在沙门氏菌、大肠杆菌O157:H7、单核细胞增生李斯特氏菌、阴沟杆菌和金黄色葡萄球菌等食源性致病微生物检测中的应用。数字PCR技术目前在转基因成分和动物源性成分定量检测中都得到了较好的应用,在食源性致病微生物中的应用技术还有待更好的发展。     

基于数码技术的机织物组织设计原理和方法

通过对机织物的结构特征及组织设计的特点进行分析,并结合数码设计技术的应用,提出一种机织物组织设计的新原理和方法。以全息组织替代传统单一组织的设计模式,设计的全息组织可以建立相应的组织库,组织库中的组织可以替代应用来改变织物效果,但不会改变机织物交织平衡的结构特征。以机织物的经纬交织平衡分析为基础,设计的织物结构能满足机织物大批量生产的技术要求,可以方便地应用于数码机织物的产品创新,特别是分层组合设计模式下数码提花织物的创新设计。     

数字经济驱动下长三角纺织服装产业数字化提升路径研究

随着国家数字经济战略的实施,纺织服装产业开始以数字化、智能化为主攻方向,以推动纺织服装企业数字化转型升级。基于中国智能制造标准化与工业PaaS平台模型,深入分析数字化技术在纺织服装智能制造中的作用。针对长三角纺织服装产业数字化建设现状进行深入调研与问题分析,在此基础上提出纺织服装产业数字化提升路径,包括搭建纺织服装产业工业互联网平台,促进数字化技术在纺织服装智能制造全过程的应用,推进纺织服装产学研在数字化领域的推广应用,建立纺织服装产业数字化转型评价指标体系,以此促进数字化技术与智能制造技术在纺织服装产业中的两化融合。     

自动桥式堆包机设计概述

介绍了桥式堆包机的结构组成及机械系统、运行系统、转弯机构和控制系统的设计要点。     

精纺毛织物数字印花技术路线探讨

通过对数字印花设备、所用液体染料及蒸化方式的选择比较,表明所确定的精纺毛织物数字印花技术路线是可行的,印在精纺毛织物上的颜色效果已达到纸质印刷品的色彩效果。