基于InSb磁敏电阻器的齿轮转速传感器

分析了InSb磁敏电阻器的工作原理和温度特性,讨论了利用偏置磁场作用于半桥磁敏电阻构成齿轮转速传感器的测试原理;针对半导体材料对温度十分敏感的特点,提出了利用浮动零点跟踪技术测试齿轮转速的方法,很好地克服了环境温度及磁场变化对磁敏电阻的影响.实验表明:其响应频率为0.5Hz～12kHz.     

InSb磁敏传感器及其应用（中）

五、InSb磁敏电阻和传感器及应用 1、InSb磁敏电阻 与霍尔器件不同,InSb磁敏电阻像其它电阻器一样是一种纯电阻性两端元件,所不同的是它的电阻随磁场的变化而变化。根据图2中几何磁阻效应原理制造的InSb磁敏电阻的基本结构和电阻值与磁场的特性曲线如图10所示。 由图10(a)可见,一个长方体InSb材料被5条In短路条(它具有金属性质)分割     

基于InSb磁敏电阻器的脉冲涡流信号处理方法研究

脉冲涡流检测方法是涡流检测技术的一个新兴分支。分析了InSb磁敏电阻器作为脉冲涡流检测元件的工作原理。应用InSb磁敏电阻器的涡流探头检测金属裂纹特征的信息提取方法。对采集的信号首先通过同步累加法处理后再经多项式拟合、小波变换实现对信号的滤波与平滑,最终选用小波变换提取裂纹的特征。实验表明:采用InSb磁敏电阻器作为脉冲涡流检测敏感元件,具有较高的裂纹灵敏度,且可以较好地反映裂纹的深度。     

“磁传感器及其应用技术”讲座：第七讲 磁敏晶体管传感器（一）

磁敏晶体管分为磁敏二极管和磁敏三极管两类。它们都属于PN结型器件,其电特性随外施磁场的改变有显著的变化。磁敏二极管出现于60年代末期,磁敏三极管出现于70年代,现我国皆有生产与应用。由于它们具有体积小、灵敏度高(比霍尔器件约高百倍左右)、使用简单等优点,故作为磁传感器可用来检测磁场、电流、位移、液位、加速度、角度等参数,也可以用其构成无刷直流电机和各种非接触开关等。一、磁敏二极管磁敏二极管简称MD,目前可分为磁性整流器(CMD)和磁敏二极管(XMD)等。由于CMD的灵敏度     

镍浆在厚膜湿敏电阻器上的应用研究

介绍镍浆料和厚膜湿敏电阻器的制备工艺。用镍浆制成厚膜湿敏电阻器的电极,并将该种厚膜湿敏电阻器的湿敏特性与采用贵金属浆料制成的同类厚膜敏电阻器进行比较,湿敏电阻器的湿敏特性完全一致,且镍浆在方电阻、附着强度等性能优于贵金属浆料。     

基于InSb-In磁敏电阻器的双限温度开关的设计

介绍一种用InSb—In共晶体薄膜磁敏电阻器（MR）制成的双限温度开关的温控机理和特性。实验表明：由InSb—In磁敏电阻器和信号处理电路两部分组成的温度开关,具有灵敏度高、控温范围宽的优点,在低温区,其灵敏度可以高达30mV／℃以上,常温下也可达到23mV／℃左右;其上下限温度调整范围为-40～120℃,测温精度可达到±0．1℃。     

半导体磁敏电阻和传感器

ＩｎＳｂ磁敏电阻元件用磁敏电阻传感器是一种新型的，重要的磁敏元件和传感器。首先，简要介绍了ＩｎＳｂ磁敏电阻元件和磁敏电阻传感器的工作原理，结构，性能等；分别介绍磁敏电阻传感器，磁性墨水文字图形识别传感器，齿轮传感器，磁性编码器，直线位移传感器，齿轮传感器，磁性编码器，直线位移传感器，无接触电位器等工作原理，结构，主要技术性能和应用。     

InSb磁敏电阻器的开发

<正> InSb磁敏电阻器是利用半导体磁阻效应制成的一种磁敏元件。因为这种元件的基本结构是一种两端型结构,所以在各种应用中,特别是在电路布局中就比四端型霍尔元件有许多优越性。     

新型InSb-In薄膜磁阻式振动传感器的设计

介绍了一种用InSb-In共晶体薄膜磁敏元件制成的准全方位振动传感器.它由两对对称轴方向互相垂直的InSb-In磁敏元件构成,可将检测方位范围由一维扩展到现在的二维平面,并用单片机P87LPC760对传感器信号进行处理,应用中可提高检测信号的准确性.经实测, 在机械振动的中低频率检测范围内,传感器的有效频带不窄于4～760Hz,其通频带内信噪比为30～32dB,经换算得灵敏度为16mV/gn.同时,得到传感器振动强度大小与磁敏电阻器输出信号关系曲线.     

基于Maxwell软件的齿轮测速传感器的磁路分析

齿轮测速传感器在工业测量和自动控制中有着广泛而重要的应用,其中尤其以磁敏类传感器应用最为广泛.对比于光电类齿轮测速传感器,磁敏测速传感器抗震动,不怕油污,特别适合在恶劣条件的工业现场使用.齿轮的形状和大小强烈的影响传感器检测到的磁通的分布,进而影响到信号的检测,因此测速齿轮可以设计成不同与传动齿轮的非标准齿轮,使得检测信号最大.有限元模拟软件Maxwell在磁场模拟中有着广泛的应用,其界面简单,使用方便,模拟真实.本论文以Maxwell为基础对测速传感器的磁路进行分析,以磁敏感芯片为中心,分析了齿轮的尺寸和形状,永磁磁铁和齿轮之间的气隙,以及永磁磁铁的磁感应强度的大小,分析的结论对实际传感器的设计有较好的指导意义.     

基于GMR的可辨向齿轮转速传感器的研制

设计了一种可辨向的巨磁阻（GMR）齿轮转速传感器。该齿轮转速传感器同时利用两路巨磁阻芯片作为敏感元件,分别采集并处理在齿轮转动过程中引起的磁场扰动信号,然后通过单片机对这两路信号进行运算处理,即可获得齿轮转动的速度及方向。所研制的可辨向巨磁阻齿轮转速传感器具有高精度、测量间隙大、便于使用等特点。     

Biological and psychological responses to two rapid shiftwork schedules

This study presents the biological responses to shiftwork in two groups of workers with different shiftwork rotas. Biological responses were studied by recording the heart rate and the changes in the circadian profile of salivary cortisol over 24?h (RIA assays). Various items were recorded through questionnaires aimed at determining self appreciation of sleep quantity, stress, health, satisfaction at work and in private lives. Thirty two male subjects aged from 23 to 56, working for the same company, having given their informed consent, took part in the study. The study was carried out under realistic conditions (at the work place) under the control of an occupational physician. Sixteen day-workers (8 am?–?6?pm) served as a reference group. Eight shiftworkers included in alternate schedules (morning M 4 am?–?12 am, evening E 12 am?–?8?pm, night N 8?pm?–?4 am) according to a system M, S, N 3/2, (3 work, 2 rest) and eight according to a system 7/5 (3M/2S/2N/5R, 2/3/2/5, 2/2/3/5) constituted the groups of shiftworkers respectively named 3/2 and 7/5. All subjects had comparable ages and BMIs. Shiftworkers expressed a higher stress level and frequency of health problems and a lower satisfaction at work than the control. Among the three groups, the 7/5 group had the best health and fitness score and was in need of less sleep. Heart rate was not affected by shift work. Conversely, consistent changes appeared in cortisol circadian profiles, the greatest changes appearing for the night shift and among the two groups of shiftworkers, more particularly for the 7/5 group. These changes correlated with self-perceived constraints of work and showed the difficulties of adaptation to shiftwork.     

A helical drive in-pipe robot based on compound planetary gearing

The modern society is fuelled by very comprehensive grids of gas and liquid pipelines. In recent years, various in-pipe robots have been developed for inspection and maintenance tasks inside such pipes. In this paper, a novel in-pipe robot is proposed and developed for gas/oil well interventions at thousands of meters downhole. Due to the nature of such intervention, in-pipe robot design must be capable of carrying a very large payload, as large as 2500?N inside a pipe with diameter as small as 54?mm. The proposed design concept is based on a compound planetary gearing system. One of the major novelties of this design is the use of pipe wall as a ring gear for one stage of the compound planetary gear system; the other novelty is the generation of helical angle when the planetary gears are expanded to press on the pipe wall. The proposed concept is compact, efficient, and has never been reported before. In this paper, the helical angle, the velocity, and load capability of the proposed system will be analyzed. The load transportation capability of the proposed robot is also measured based on an experiment. Initial data have shown great potential in carrying large payloads.     

AChE/IL-GR/CHI/GCE结构酶电极的研制及其对毒死蜱农药的检测

利用氨基功能化离子液体修饰石墨烯(IL-GR)的独特性质,以壳聚糖(CHI)为交联剂,首先在玻碳电极表面固定IL-GR,然后吸附乙酰胆碱酯酶(AChE)制得新型有机磷检测酶电极(AChE/IL-GR/CHI/GCE),并用于卷心菜样品中毒死蜱农药残留的测定。采用透射电镜(TEM)表征了IL-GR的形貌,采用循环伏安法(CV)和差示脉冲伏安法(DPV)研究了酶电极的电化学性质。结果表明,在优化的实验条件下,抑制率(I%)与毒死蜱浓度的对数在1.0×10-10mol/L~1.0×10-5mol/L范围内呈良好的线性关系,检出限为7.0×10-12mol/L(S/N=3)。测定了卷心菜中毒死蜱的含量,回收率为92.3%~108.6%。     

A global compositional complexity measure for biological sequences: AT-rich and GC-rich genomes encode less complex proteins

Different local regions of natural amino acid or nucleotide sequences show remarkable heterogeneity in residue composition, reflecting diversity in evolutionary history and physiochemical constraints. Compositional complexity measures are helpful for describing and understanding this variegation. Motivated by some open problems in comparative genomics and protein folding, we have developed a new 'global' compositional complexity measure, G1, which overcomes a crucial limitation of earlier methods. The 'local' measures used in previous research resemble entropy functions and are inherently dependent on an underlying probability distribution. Local measures cannot rigorously compare complexity across sequences of substantially different size, because real sequences show very irregular heterogeneity and do not have the necessary ergodicity in scaling and asymptotic properties. G1 is a member of a new class of scale-independent, distribution-independent complexity functions. For a sequence S of length L on an N-letter alphabet, G1 is derived from ratios in the integer partition lattice, P?L,N? of L with N parts, where the elements of P?L,N? are the state vectors of S, (n1, n2,..., nN), ranked by an order principle. We present theorems and proofs relating to the metric properties of G1 and its relationship to other state-vector-dependent compositional complexity functions, together with a fully-efficient O(L) algorithm to compute G1. The distributions of G1 were calculated for the entire sets of translated proteins encoded by extensively sequenced genomes. The results establish the existence of a clear evolutionary principle, common to bacteria, archaea and eukaryotes, that the proteins encoded by more extreme AT-rich and GC-rich genomes have generally lower compositional complexity than those of more typical organisms.     

Selected physiological and psychobiological responses to physical activity in different configurations of firefighting gear

The aim was to examine selected physiological and psychobiological responses to different configurations of protective firefighting gear. Career firefighters (n = 10) walked on a treadmill (3·5?km · h^?1, 10% grade) for 15?min in three different clothing configurations. On separate days subjects wore: (a) ‘station blues’, (b) a hip boot configuration of firefighting gear, and (c) the current ‘NFPA 1500 standard’ gear. Physiological, psychophysical, and psychological measurements were recorded pre-exercise (5?min), during exercise (15?min), and during post-exercise recovery (10min). Repeated measures ANOVA revealed significant main effects for condition, time, and interaction (p < 0·001) for heart rate (HR), rectal temperature, mean skin temperature, oxygen consumption, breathing distress, thermal sensations, and affect. Furthermore, post hoc analyses revealed that all variables were significantly higher in the NFPA 1500 standard versus the hip boot or the station blues clothing configurations. These data suggest that the current NFPA 1500 standard configuration results in greater physiological and psychobiological stress at a given workload.     

A note on the comparison between total ozone from Oslo CTM2 and SBUV satellite data

The results of a comparison between total ozone amounts derived from solar backscatter ultraviolet (SBUV) satellite observations and those calculated from the chemical transport model Oslo CTM2 are presented for the period 2001–2007. Monthly mean total ozone amounts from improved model simulations were used to compute monthly, seasonal and annual zonal means over 10° latitude zones, and compared with respective satellite retrievals over the northern and southern hemispheres. The results show that the improved model simulations slightly underestimate total ozone over the northern hemisphere when compared with the satellites by 1.4% on average, and slightly overestimate total ozone over the southern extra-tropics, middle and high latitudes by 1.6% on average. The mean difference between the model- and satellite-derived total ozone columns from 75°S to 75°N is estimated to be about ?0.3%. A linear regression analysis between the model- and satellite-derived total ozone data shows statistically significant correlations between the two data sets at all latitude zones (about +0.8 in the tropics and more than +0.9 over all other latitudes). The annual cycle of total ozone is shown to be well reproduced by the model at all latitudes.     

含间隙齿轮碰振系统的全局动力学分析

为研究含间隙齿轮碰振系统的全局及周期运动的稳定性及分岔条件,建立了齿轮副主动轮的单自由度非线性动力学模型.运用非光滑系统Melnikov理论研究齿轮系统异宿轨道全局分岔条件,然后,求得各分段系统的通解,再将每个切换面作为Poincaré截面,运用组合映射的方法分析系统的周期运动特性.最后通过数值模拟,得到不同参数条件下系统的运动状态和分岔特性,验证了Melnikov方法分析齿轮非光滑系统的有效性.     

MRTG在校园网中的应用

MRTG(MultiRouterTrafficGrapher,MRTG)是一个监视网络链路流量负载的工具软件,它通过SNMP协议得到被监控设备的流量信息,通过这些信息网络管理员能非常方便直观地了解设备流量及负载。