示准化学科行为互换性定律的创建

本文讨论了互换性定律的族系,研究了非训练行为不准确现象,讨论了行为互换性的需求,推论了行为互换性定律的存在,建立了行为互换性的概念,创建了行为互换性定律的命题及其数学模型,详述了定律的内涵,分析了行为互换性与其他互换性的关系,讨论了行为互换性定律的对象范围、互换类型、自身特点和作用意义,对行为互换性定律进行了验证分析,讨论了行为互换性定律的应用,并给出了应用例子。     

标准化学科几何互换性定律的创建

本文讨论了规律和定律的关系和特点,讨论了几何互换性的本质关系,推论了互换性定律的存在,创建了动配合互换性定律、定位配合互换性定律、紧配合互换性定律,建立了定律的命题、数学模型和关系模型,详述了每个定律的内涵,创建了支持互换性工程应用的几何互换性空间,讨论了互换性定律的应用,创建了广泛适用的互换性空间。     

标准化学科功能互换性定律的创建

本文讨论了互换性的新模式——功能互换性,阐述了功能互换性的概念和特点,创建了功能互换性的命题,解读了功能互换性命题的内涵及其数学模型,给出了功能互换性的关注情形,探讨了功能互换性的适用范围和作用意义,验证了功能互换性定律的有效性,说明了功能互换性定律的应用,并给出了指导功能互换性定律应用的实例。     

某型车辆驾驶室内部噪声分析研究

建立了某型车辆驾驶室结构的三维有限元模型,对驾驶室进行了试验模态分析,得到了模态参数,检验和修正了结构的三维有限元模型,对驾驶室结构进行了动态响应分析.采用边界元法进行了驾驶室内部声学特性研究,对驾驶员耳旁的声压和声学灵敏度进行了分析,得出了驾驶室内声场的声学特性,对驾驶室结构提出改进措施,有效地降低了车内噪声.     

作业本中闪烁出孩子的希望之光

一叶知秋,一字知人。一滴水折射出了七彩之光,一本作业也同样闪烁出了孩子的勤奋,闪烁出了孩子的诚实,闪烁出了孩子的认真,闪烁出了孩子的聪明……闪烁出了一个热爱生命,热爱生活,积极向上的孩子。     

智能型电子分克秤的研制

介绍了智能型电子分克秤的工作原理及硬件、软件的系统设计.整机的硬件设计,采用高阻值的传感器,软件由单片机控制完成双积分A/D转换,使整机既降低了功耗又降低了硬件成本,实现了分检计量智能化的控制,提高了工作效率,减轻了操作人员的劳动强度,避免了产品检测过程中的人为误差.     

浅谈标准养蟹优化质量调整结构促进增收

通过农业标准化示范区建设项目的实施,促进了农产品质量安全水平的提高,延伸了产业链条,加快了全市农业产业化、现代化的进程,提高了农民的标准化意识,改善了生态环境,促进了可持续发展,为促进农业增效、农民增收起到了巨大作用。     

基于VBA的千分尺证书记录系统

介绍了一种以VBA作为研发平台的千分尺证书记录系统。介绍了系统的结构,并详述了几个关键模块的设计和系统的防错功能,千分尺证书记录系统的研发,减轻了工作量,降低了劳动强度,杜绝了人为产生的偶然性失误,提高了劳动效率。     

继往开来更上一层楼

中国安装协会成立25周年了。25年来,随着我们国家的改革开放,市场经济的蓬勃发展,中国安装协会从成立到成长,走过了不平常的历程。历届理事会和秘书处的工作者,贡献了他们的聪明才智,书写了可歌可泣的篇章。协会已经成了安装企业交流合作的平台,成了企业和政府连接的通道,成了行业进步的集散地,成了安装企业之家。     

标准化学科核心原理的构建（上）

本文研究提出了原理构建的必备要素,以引导学科原理的构建,按照原理要素关系,分析了过去所提出原理存在的问题,论述了标准化原理重建的原因,研究提出了标准化学科的统一化原理、互换性原理、通用化原理、系列化原理、模块化原理的理论命题,讨论了每个原理的规律性内容,分析了5个原理间的相互关系,对每个原理应用七要素进行了验证,给出了每个原理相应的应用方法。     

Noise of piezoelectric accelerometer with integral FET amplifier

Since significant progress has been achieved in the development of low-noise piezoelectric (PE) accelerometers with integral FET amplifiers, detailed noise analysis of the system PE transducer-FET amplifier, and obtaining the engineering formula for its noise floor has become vital. As a result of this analysis, the formula for the noise floor of PE accelerometers in terms of acceleration spectral density is obtained at wide frequency band. Noise floor of the low-noise PE accelerometer comprising low-noise JFET charge amplifiers with some particular parameters of the PE transducer and the JFET amplifier was measured. The theoretical and experimental curves of the PE accelerometer's noise floor have a good correlation with each other at frequencies from 1 Hz to 10 kHz. The contribution of the different noise sources to the overall noise floor is shown. Those noise sources include the mechanical-thermal noise and electrical-thermal noise of the PE transducer and all main noise sources of FET amplifiers: the thermal noise voltage of the FET biasing resistor, the thermal noise of the series resistor between the PE transducer and the gate of the FET, the channel thermal noise voltage, the 1/f noise voltage, and the shot noise current in the gate circuit. At low frequencies, the f/spl les/50 Hz noise floor is determined mainly by the FET biasing resistor's thermal noise and the PE transducer's electrical-thermal noise. At frequencies from about 50 Hz to about 1 kHz, the contribution of the PE transducer's electrical-thermal noise dominates over the amplifier's noise sources by a factor of less than 2. At frequencies above 1 kHz, noise floor is determined mainly by the JFET channel thermal noise and the PE transducer's electrical-thermal noise.     

Noise properties of a quadrature phase tracker for interferometricoptical fiber sensors

The noise performance of an electronic quadrature phase-detection system for interferometric optical fiber sensors is presented. Three noise sources are discussed in this work, namely, synchronous detection-circuit noise, phase-perturbation noise; and additive amplitude noise. We determined the output signal-to-noise ratio (SNR) experimentally as a function of input phase power for each of the three noise sources. For uncorrelated synchronous detection-circuit noise the output SNR increases monotonically with input phase power. For correlated noise the output SNR has distinct peaks due to noise cancellation. System performance is limited by uncorrelated detection-circuit noise which exhibits a threshold behavior in output SNR at a phase shift of 25 mrad/Hz^½. The phase noise has a more conventional behavior in the sense that SNR gain occurs only at the expense of dynamic performance. Uncorrelated amplitude noise also displays noise cancellation at certain discrete values of input phase, as is the case for correlated synchronous detection-circuit noise. System insensitivity to correlated light-source amplitude noise is evident from the fact that the output SNR is more than 30 dB higher than the input SNR     

成灌快铁高架桥梁区段噪声测试

结合成灌快铁高架桥梁的噪声试验,对高架桥梁附近的噪声传播规律进行研究。实测结果表明：桥梁结构噪声以低频为主,采用线性计权进行评价更为合适;实测高架桥梁附近的噪声在100 Hz以下和800 Hz附近出现噪声峰值,前者主要为桥梁结构噪声;桥梁结构噪声主要集中在桥梁斜下方一定区域,且随横向距离的衰减较慢。将实测结果与建立的噪声简化预测模型进行比较,二者吻合较好,预测模型较好地反映了快速铁路高架桥梁附近的声场分布。     

民用航空涡扇发动机核心机噪声预测评估

随着涡扇发动机的采用,核心机噪声成为主要噪声源。因此研究涡扇发动机核心机噪声特性就显得很重要。本文将涡扇发动机分为燃烧室和涡轮噪声再合并为核心机噪声的方法,并用于分析了CFM56-7B核心机噪声特性,将静态下核心机噪声级与燃烧室噪声级、涡轮噪声级做了比较,且将静态与起飞状态下核心机噪声有效感觉声压级做了比较。     

摊铺机噪声测试分析与治理

通过对某沥青混凝土摊铺机各主要声源的近场声和驾驶员耳旁噪声进行测试分析,识别出对驾驶员耳旁噪声贡献较大的噪声源.针对这些噪声源的特性采取相应的降噪措施,在进、排风口分别设计了消声结构,使摊铺机噪声明显降低.测试结果表明,该摊铺机噪声指标达到了国家标准规定的水平.     

Impossibility of Linear Two-Port Noise-Parameter Measurement with a Single Temperature Noise Source

The noise parameters of a linear two-port are usually evaluated through four measurements of the noise figure of the two-port, and the noise figure is in turn determined through the measurements of the noise power output of the two-port when a noise source is connected at its input. It is shown that if the noise power output is the only measured quantity, then the noise parameters cannot be calculated from measurements carried out with a single value of the source noise temperature. The minimum requirements for the determination of noise parameters are established.     

潜艇振动噪声的控制研究

系统介绍了潜艇振动噪声的主要来源：机械噪声、螺旋桨噪声和水动力噪声，并从这三个方面详细论述了具体的控制方法。指出螺旋桨噪声、水动力噪声和设备机座机械噪声被有效抑制后，管道系统便成为“安静型”潜艇的主要噪声源。从管道的被动控制和主动控制两个方面论述了管道振动控制的研究现状，并对潜艇振动噪声控制的研究进行了展望。     

Improving performance of neurons by adding colour noise

Noise is not always an interfering signal which perturbs the system. On the contrary, noise signals can enhance the performance of some non‐linear systems such as stochastic resonance (SR). These systems can detect the weak input signal when it is added to the noise signal. According to this property, SR models play a significant role in the functioning of the brain for detecting weak input signals and synchronisation of neural connections. In this study, the authors model neurons as SR systems where different types of noise, i.e. white noise and pink noise, are employed to amplify the weak nervous signals. They demonstrate colour noise, in particular, pink noise enhances the performance of the SR system to amplify the input signal. Furthermore, pink noise has a wider range of optimum values in comparison to white noise. Therefore, they can conclude that neurons are more sensitive to detect the signals that carry pink noise than signals with white noise or without noise. Hence, the retrieving ability of neurons can be improved by adding pink noise.Inspec keywords: stochastic processes, white noise, neural nets, brain, noise, neurophysiologyOther keywords: interfering signal, particular noise, colour noise, weak nervous signals, pink noise, white noise, SR system, authors model neurons, SR models, noise signal, weak input signal, nonlinear systems     

高校新校区交通噪声预测评价

交通噪声是造成高校环境噪声超标的主要因素,尤其对城市道路下穿校园的新校区影响更大。运用噪声预测方法对在建的安徽理工大学新校区进行噪声预测评估,为其环境规划提供相应的依据和技术支持。通过测量统计校园周围道路不同类型的机动车流量数据,结合测量已有道路的交通噪声,利用Cadna/A噪声预测软件,建立新校区交通噪声模型,计算并绘制噪声网格分布图,并提出相应噪声控制措施。结果表明,通过采取在校园四周增加围墙,并在南北下穿城市道路旁设置声屏障等措施后,可以改善校园声环境,使其达到国家I类地区噪声规定标准。