Papers by Keyword: Detector

Abstract: Realize the goal quick and accurate location when the detection signal is weaker, puts forward a Fast Intelligent Tracking algorithm(FITA) with the Gain Adjustable. Wiht the goal image move in four quadrant detector, it’s size, location and output signal related to a linear probe interval. In this interval, a liner relation can be get between the spot position and the corresponding output signal. The target quick location algorithm is realized with this relation. On the other hand, the sum signal of the four quadrant detector is sampled in real-time, this sum is related to the sensor’s signal strength, then the change rate of the signal strength can be get, using adaptive learning ways to get the change trend of signal strength, and realized dynamic adjustment of the signal gain, in order to improve the signal resolution ratio when signal is weak, the tracking accuracy can be improved with this way. The experimental data show that FITA algorithm can rapidly locate position in the linear interval and accurately track through the dynamic change signal gain for the weaker signal. The track error can be improved to 1.9%.

Abstract: The performance of the automatic level control（ALC） system determines the stability of the microwave signal source output power, accuracy and linear flatness in each frequency range, directly determining the signal generator power characteristic indicators. This paper gives an implementation of a high-performance feed-forward ALC circuit, the negative feedback loop consists of the power detector circuit, logarithmic amplifier, the integral hold circuit, attenuator driving circuit, PIN attenuation circuit and so on.

Abstract: An intelligent fire alarm system has been designed based on MCU. The system is mainly composed of fire detector, fire controller and radio communication. This system can accurately display the environmental temperature. When the fire occurs, the system can alarm and remind of the staff on site working. At the same time, it can also display fire graphics, time, and temperature on the LCD and control the system very good.

Abstract: The change of reservoir dam’s piezometric level can reflect the dam’s internal structure, piezometric level number obtained by using detection technology can directly judge the interior defect, therefore, whether piezometric level detection is accurate or not is related to dam’s safety. After years’ research, the design scheme of integrating mechanics and electrics is put forward by combining with today’s popular single chip computer technology and digital measuring technology, which is the scheme that we adopt the digital detection technology to convert the water level into pulse digital signal directly and calculate the piezometric level according to the number of single pulse. It is necessary to develop a Piezometric Tube detector with teatures of high precision, high degree of automation and high speed of processing and acquisiting data and put it into use.

Abstract: To reduce the fracture probability of InSb infrared detector in thermal shock from room temperature to 77K, for 16×16 mesa structure InSb infrared focal plane array detector with underfill, here ANSYS, is employed to research the impacts from both indium bump diameters and heights on both Von Mises stress and its distribution. Simulation results show that when the diameters of indium bump increases from 20µm to 36µm in step of 4µm, the maximal Von Mises stress in the InSb chip increases slowly. Besides, when the height of indium bump increases from 8μm to 24μm in step of 8μm, the maximal Von Mises stress in the InSb chip reduces from 1200MPa to 1030MPa. Von Mises stress of Si readout integrated circuits is also much smaller than that of InSb chip.

Abstract: This document deals with the study of a carbon dioxide detector, which is used in survivors searching in earthquake ruins. In order to find the carbon dioxide of exhaled gases of earthquake survivors in the narrow space, we compared the different types of carbon dioxide sensors. At last, we selected the infrared sensors, which direct access to digital signals through the microcontroller, and has a temperature compensation function. The result of measuring was displayed in a vacuum fluorescent displayer. When it achieves the preset value, the sound and light alarm will be triggered. The test results show that the detector is fit for narrow space survivors search.

Abstract: Highly c-axis oriented ZnO films were grown on the nucleation sides of freestanding diamond (FSD) substrates with homobuffer layer by radio-frequency (RF) magnetron sputtering method. The effect of oxygen partial pressure (O₂/Ar) on the properties of ZnO films was studied. ZnO-based UV photoconductive detector with planar interdigital (IDT) electrodes was fabricated by the lift off technique. Current-voltage (I-V) characteristics of the detector under ultraviolet (UV) light were measured and discussed.

Abstract: In this work, the effect of split ratio and the column flow in determination of OCPs in Traditional Chinese medicines are discussed in the name of heptachlor. When the split ratio is 60:1, the measured concentration is close to the actual concentration; on the contrary, they lead the measured concentration lower than the actual concentration. The column flow has not obviously effect on result. The split ratio is considered in OCPs analysis.

Abstract: As thin metal films are known to act as wide-band absorbers for infrared radiation, in this paper Ni metal films are prepared on the Ge surface of double-sided polishing, The results showed the absorbing properties of the metal layer are strongly influenced by the dielectric function of the sensor material. This paper also describes one multi-layers structure as absorber. The structure included a reflector layer of 100-nm-thick Ti (e-beam evaporation), 2-µm-thick polyimide(spin-coating), and 14.9-nm-thick Ni film (e-beam evaporation). These contain a half transmissive thin metal film, a total reflective thin metal film and a quarter-wave polyimide film. The results showed that, measured performance matches well with theoretical predictions.

Abstract: The high absorption characteristics, the complex mechanism and the great potential application in detectors of micro-structural material aroused extensive attention. In order to understand the impact of the micro-structure, the optical simulation method based on Monte Carlo is used for reflection characteristics of micro-structural material with the cell of pyramid construction. In this simulation, the body material is made of gold, which can avoid the effect of tranmittance, with a number of 400 cells. The bottom square of each structure is 50×50 µm, and the height of cells is adjustable. Then the relationship between the height and reflectance can be built up. However, a very complex relationship between the reflectance and the input parameters, including refractive index, extinction coefficient and the structure of the material is showed from simulation result. Generally, the reflectance decreases while the height increases.