一种以AOTF为核心的农药荧光检测系统

提出了一种将 AOTF 技术用于农药含量检测的荧光光谱系统。该系统分别采用以α-Quartz,TeO2 晶体作为声光介质的激发和发射色散元件 AOTF,以高压短弧氙灯为激发光源,利用光纤探测并传输荧光,由数据采集卡进行数据接收和 A/D 转换。该系统通过声光调制产生单色光,由超声射频的变化实现光谱扫描,没有机械调谐部件,故波长切换快、结构简单。西维因农药的荧光特性测量结果表明,系统的荧光波长范围为 500-750nm, 光谱分辨率为 10nm。当激发光波长为320nm,荧光波长为 647nm,西维因溶液浓度为 0.0-120.0μg/L 时,系统具有较好的线性关系,线性相关系数 r 为 0.9991。它可用于对粮食作物中的农药残留的检测和荧光光谱分析。     

一种新型农药浓度荧光测量系统的研究

根据声光可调滤波器（Acousto-Optic Tunable Filters，AOTF）的分光原理研制了一种新型的农药浓度荧光俭测系统，系统以高压短弧氙灯为激发光源，以AOTF为分光元件，利用光纤探测传输荧光，采用数据采集卡实现数据接收和A／D转换，由微机进行数据存储和显示，并且利用该系统实现了对西维因农药浓度的荧光持性的测量。结果表明：系统测量光谱范围为230nm～750nm，光谱分辨率为10nm，在激发波K319nm、荧光波长650nm、西维因溶液浓度为0．0～120．0μg／L时系统具有较好的线性关系，线性相关系数r为0．9991，该系统达到了荧光检测的指标。     

基于CCD器件的苯甲酰脲类农药荧光检测系统

根据苯甲酰脲类农药在紫外光的照射下能够发出荧光的机理,设计了一种基于CCD(电荷耦合器件)的检测该类有机农药残留的光纤荧光测量系统.该系统以脉冲氙灯为激发光源,利用光纤探测和传输荧光,采用线阵CCD代替传统的光电倍增管作为荧光信号的光电检测元件,同时配备A/D高速数据采集卡,实现了单片机控制下荧光信号的光电转换以及数据采集,进而实现了对卡死克和盖虫散(氟铃脲)农药浓度的测量.实验结果表明,在激发波长分别为290nm和345nm时,卡死克和盖虫散的荧光强度分别在360nm和418nm处达到最大,最低检出限分别为12 μg/L和20 μg/L.在25～1 000μg/L范围内,荧光强度和溶液浓度基本呈线性关系.该测量系统灵敏度高,线性范围宽,可以满足荧光检测的要求.     

基于含砂液流振动信号特征分析的出砂监测实验研究

针对高含水期油田出砂监测问题,提出一种利用安装在管线上的振动传感器,结合信号采集系统,通过分析含砂液流冲击管线产生的振动信号时-频特征,实时监测出砂量变化的方法。以水-砂两相流振动信号特征为研究对象,设计室内出砂监测实验,基于STFT时-频分析方法,研究携砂流的速度、砂粒粒径大小、含砂量与出砂振动信号时-频特征关系。通过设计出砂信号校准方法,进一步建立了出砂量监测数学模型。结果表明,基于携砂流振动信号时-频分析的振动监测方法可以有效检测砂粒信息,水-砂两相流中,砂粒激发的特征频段为10.5～12.5 kHz,含砂量监测模型的误差在14%以内,该方法为更复杂的多相流出砂监测研究奠定了基础,为油井安全生产提供了技术保障。     

残留农药的光学检测技术和去噪处理

根据残留农药受到紫外光激发能够发出荧光的机理,研究了一种用于测量残留农药浓度的荧光光纤测量系统.该系统采用脉冲氙灯作为激发光源,光纤探测并传输荧光,电荷耦合器(CCD)作为荧光检测系统的光电转换器件.由于荧光是微弱信号,系统采用微弱信号处理电路对CCD输出信号进行了处理,并且采用相关双采样技术有效地抑制了CCD输出噪声的干扰.用该系统对吡虫啉溶液进行荧光分析,实现了对吡虫啉的快速测定,在5～100μg/L范围内,荧光强度和浓度基本呈线性关系,线性相关系数为0.9959.     

动态光电显微镜刻线瞄准信号的处理方法

研究了激光干涉比长仪的动态光电显微镜刻线瞄准信号的处理方法。分析了基于硬件电路的信号处理方法,及基于高速A/D采样、计算机数据处理的软硬件结合的信号处理方法,分别介绍了这两种方法的系统组成及工作原理。实验证明,前者抗干扰性能差,瞄准精度低;后者实现对刻线信号均匀等距采样,瞄准精度高,在测量速度达3mm/s时,可实现2nm的瞄准分辨率。     

基于UIO-66-NH2构建的Turn-On型荧光传感器在检测硫化钠中的应用研究

本文利用pH响应的金属有机骨架材料UIO-66-NH_2检测硫化钠,材料的分散液在没有目标物尿素存在时,体系的p H不发生改变,此时只能测到背景荧光信号;若加入目标物硫化钠时,硫化钠在溶液中水解使溶液的pH上升,此时UIO-66-NH_2中配体上的邻位氨基去质子化使材料UIO-66-NH_2在330 nm处激发时,在425 nm处产生发射信号增强的过程,基于此构建了对硫化钠快速检测的传感器。相比较于传统方法本实验设计的传感器步骤简便,操作简单耗时短可以实现硫化钠的快速检测而且具有方法的检测限低等优点。     

2m比长仪纳米级高精度刻线自动瞄准系统

阐述了2m比长仪刻线瞄准系统的组成,对其光电显微刻线成像的原理及刻线图像信号进行了分析,根据其刻线信号的特点,研究了其高精度的刻线信号自动处理系统,该系统基于FPGA现场可编程电路技术,实现刻线信号的自动门控触发、自动滤除虚假刻线信号,配合计算机信号自动处理软件可以实现刻线测量的高精度自动瞄准.最后对2m比长仪的瞄准精度进行了测试实验,实验结果表明,测量金属标准线纹尺时,2m比长仪单次测量刻线瞄准精度优于10nm(1σ).     

一种FPGA实现看门狗电路功能的方法

为提高系统集成度,降低硬件开销,研究利用FPGA实现看门狗电路的方法,从而去掉硬件看门狗电路。对硬件看门狗电路的工作过程进行分析,给出利用FPGA实现看门狗电路的方法:利用FPGA的系统时钟对单片机送出的喂狗信号进行监测,当单片机由于程序跑飞而进入死循环后,喂狗信号消失,FPGA判定单片机工作异常,自动产生一个脉冲信号复位单片机。实验证明,利用FPGA实现看门狗电路定时精度更高,在1KHz系统时钟FPGA系统中,定时精度可以达到1ms。     

岩石破裂电磁辐射监测系统研制

为满足有关岩石破裂电磁辐射研究的需要,研制一套电磁辐射监测系统。该系统由电磁感应探头、信号调理电路和数据采集系统组成,可对频率在1kHz~1MHz内的微弱电磁场进行监测。电磁感应探头可感应空间中某一方向的电磁场变化,并将其转换成电信号;信号调理电路对探头输出的电信号进行放大、滤波,并实现放大滤波电路与计算机的电气隔离;数据采集软件基于LabVIEW编写,用于对监测到的信号进行记录和显示。实验结果表明：该系统性能稳定,操作简便,能够有效地监测岩石破裂所产生的电磁辐射,对岩石、混凝土等材料的力-电-磁研究具有重要意义。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...