Ultravioletatmospherictransmittanceis a key parameterinreflectingtheopticalcharacteristicsof the atmospherein theultravioletregion.It is practicallysignificantin providingthe basis for ground-basedultravioletobservation,especiallyinsite surveys,telescopeconstruction,and terminalequipmentdevelopment.In this paper, commonmethodsfor obtainingultravioletatmospherictransmittanceare introduced,includingcomputationalsimulationand instrumentalmeasurement,and their propertiesare comparedand analyzed.Moreover, a new method,usingthe moonas a measuringobjectisproposedto acquirethe ultravioletatmospherictransmittanceat night,and somesuggestionsare put forward

紫外杀菌消毒早已成为一项应用广泛的成熟技术,新冠病毒肺炎疫情的出现引起了大家对这种技术手段的再次关注和兴趣,一些紫外杀菌消毒设备出现热销现象.紫外辐射能有效杀灭细菌和病毒早已是不争的事实,理论上,新冠病毒自然也是能被足量的紫外辐射有效杀灭的.

In this paper, we present a method to detect ultra-low level light ranging from several mean photoelectrons (MPEs) down to 10 -5 MPEs. It is based on the Poisson statistics algorithm and a double time windows technique with a silicon photomultiplier (SiPM) and a field programmable gate array (FPGA). It measures the mean incident photoelectron number of pulsed light with zero peak statistics of the Poisson distribution to reduce the influence of the correlation noises and the dark count rate (DCR) fluctuation. The linear measurement ranges from ~10 -4 MPEs to ~10 MPEs (i.e., ~97 dB) were demonstrated with double 35-ns time windows at room temperature. Its upper detection limit is determined by the availability for the zero peak counts of the Poisson distribution, and the lower detection limit is mainly determined by the DCR of the SiPM. By narrowing the time window to ~550 ps or decreasing the operating temperature of SiPM to -30 °C, the detection limit can be further decreased to ~10 -5 MPEs. This method, with capability to record the arrival time of incident photons, demonstrated an instrument response function (IRF) of ~214.9 ps (FWHM), showing its compatibility to the time correlated photon counting (TCPC) technique and the time of flight (TOF) measurement.

Averaged LED Intensity was defined in CIE 127, in which two measurement conditions were proposed, both required the area of entrance aperture to be 100 mm(2). The CIE 127 LED measurement method is widely accepted. Circular entrance aperture is usually used in commercial photometers, but the photosurface of silicon photodetector is square. However, when LEDs with a narrow beam angle are measured their Averaged LED Intensity, the result may vary due to various aperture shapes. In this paper, a mathematical measurement model is built, then the uncertainty of measurement introduced by shape of aperture is rigorously evaluated by comparing the prediction of model and the results obtained from measurement experiments. It is an effective quantitative analysis to the impact of aperture shapes on accurate measurement of Averaged LED Intensity.

The structure,measuring principle and applying properties of a contact-type luminance meter are described. And a light source which can provide a uniform diffuse surface is presented and applied to calibrate three contact-type luminance meters. In comparison with the luminance standard in National Institute of Metrology for verifying contact-type luminance meters,this calibrating method shows good traceability and accurate certified value. Finally,the practicality of applying several commonly diffuse surfaces to calibrate contact-type luminance meters is discussed briefly.

国际照明委员会的CIE 127号文件专门针对发光二极管(LED)的光辐射测量方法给出了A、B两个测量“LED平均发光强度”的条件,并得到世界同行的普遍认可.然而,实验测量中发现同一只LED管在不同的测量条件下的平均发光强度相差悬殊,甚至有LED管在A、B两个不同条件下的平均发光强度测量值相差近10％,严重影响了LED光度量值的准确评价.对LED光强空间分布数学建模的分析,通过计算以及实验验证表明将测量角定为0.5.,测量距离变为645 mm,能够将LED光强空间分布不均匀对LED平均发光强度测量的距离影响减小到0.5％以下,从而保证LED平均发光强度量值的一致性.

High-speed optical detection system or photoelectric detectors have been widely applied in the photo-metric measurement of strobe light and targets of dynamic display .This paper presents a set of measurement device that can complete accurate measurement of response time of the photoelectric detection system or photoelectric detector, and this device is capable of measuring the fastest response time of 10 In order to verify the quality of the laser square wave , a photo-multiplier tube (PMT) is prepared as the detector of a fast optical detection system .So this device also has the ability to measure the instantaneous luminosity values of strobe light and dynamic -displaying targets.-7 s.

Photometers are widely used for the measurement of the average LED intensity as defined by CIE 127, under the circumstance that LEDs have many kinds of intensity spatial distributions. Significant measurement errors can be resulted due to the following facts: 1) a photometer with a diffuser generally has a spatial response that is stronger in the center of the detector; and 2) LED angular distributions of intensity often have a sidelobe about the central axis rather than a central peak. A special measuring facility for illuminance intensity distribution of LEDs and spatial response distribution of photometers has been designed. An evaluation factor “ c” has been introduced to describe the spatial response distribution uniformity of photometers. Three kinds of photometers with different spatial response distribution were used to measure the averaged LED intensity individually. Experiment shows that the photometer with a diffuser has a response distribution of a cosine function, and the illuminance intensity distribution of LEDs generally presents a sine, trapezoidal, or cosine function with the 6.5 ° field of view for CIE Condition B. The results show that the measurement errors could be more than -5.10% when using the photometer with a diffuser to measure the average intensity of LEDs with a narrow beam angle. It is very important that the uniformity of spatial response distribution of the photometer should be considered when calibrating Averaged LED Intensity as it can introduce a significant error.

针对目前利用光纤和复眼透镜获得紫外辐照均匀性较差的现象,提出添加光学积分棒和均匀磨砂石英片改善光纤照射装置均匀性的方法,实测表明改善效果十分显著.选取紫外辐照中的紫外线A(UVA)波段作为测量对象,光纤入射端添加光学积分棒后,80 mm×80 mm辐照面均匀性由原来的±8.9％提高到±3.5％,中心30 mm×30 mm区域内均匀性由±3.3％提高到±0.7％.在此基础上,再在复眼透镜入射端添加磨砂石英片后,中心30 mm×30 mm区域内均匀性可达±0.6％,且原先偏心分布的紫外辐照呈现出中心轴对称分布.另外还提出了提高紫外辐照度的同时改善辐照均匀性的多光源叠加法,结果表明,利用两个光纤照射装置叠加辐照,80 mm×80 mm的辐照面上辐照度及均匀性分别约为30 mW/cm2和±3.9％；利用三光源叠加经复眼透镜投射,直径为80 mm的辐照面内辐照度和均匀性分别约为60 mW/cm2和±2.4％.

Astronomy is a discipline based on observations.Trairring of talents in astronomy and public education in astronomy pose various requests to astronmrucal practice teaching.For recent years,Department of Astronomy of Beijing Normal Universily has built multi-level of practice platform for astronomical teaching,providing targeted practice teaching conditions for professional and non-professional,undergraduate and graduate students.New explorations and attempts have been carried out in practice aspects of training of high-quality astronomical talents and teaching of high-quality astronomical public courses.A number of innovative achievements in education and teaching have been obtained which are worth of application and popularization.

AbstractA night-sky luminance survey was carried on in Beijing to assess the level of light pollution. The luminance of the zenith night sky and skies in four directions at six sites with different distances from the city center was measured by using a photometric luminance meter. The Xinglong Station of National Astronomical Observatory was included to study the impacts of city lights on an astronomical observatory. The survey shows that the night-sky luminance decreases with increasing distance from the city center. Measurement results indicate that outdoor lighting in the Xinglong county town which is close to the observatory has non-negligible influence on the night sky at Xinglong Station.

In view of low sensitivity of CCD arrays in the ultraviolet range, a new measuring method for ultraviolet spectrum with a 32-anode linear photomultiplier tube (PMT) array is presented. A spectrum measurement system that includes a spectroscopic design and data acquisition circuits, together with the system-controlling software, has been developed for the PMT array. Compared with a spectrometer which employs a back-thinned CCD with the highest ultraviolet sensitivity, experiments indicate that the system has the same sensitivity as the spectrometer which works at the integration time of about 2 s, while requiring less than 7 ms for one single measurement. It is able to perform time-resolved measurements even in weak light applications where CCD spectrometers need to work at long integration times.

Spectrometers play an important role in the domains of spectral measurements and analysis. In the development trend of miniaturization and portability, using linear CCD as the detector of spectrometers is the key technique. The main task of CCD spectrometer calibration is to obtain the relationships of wavelength vs. CCD pixel number and absolute spectral radiation flux vs. photon count. In the process of wavelength calibration, sometimes traditional linear fitting method may produce a large error. Using the emission spectra of a low pressure mercury lamp as the reference spectra, least square method is applied to determine the function of wavelength vs. CCD pixel number and the third order calibration parameters of the fitting curve are calculated. During the calibration of absolute spectral radiation flux, a standard radiation lamp is used as the calibration source, which solves the difficulties of determining the propagation loss and CCD spectral response. Mathematical deduction and experimental research show that this calibration method is effective and feasible. The proposed method has been successfully applied in the production of CCD spectrometers.

The principle and methods of linearity measurement are discussed.An intelligent measurement system is designed for linearity of a photoelectric detector.The system is based on the method of two lights addition for irradiance and the principle of light blended in integral global.The photoelectric characteristic of supper brightness LED is measured.The result proves that the supper brightness LED is an excellent light source.The course of measurement is auto-controlled by the computer.The theory and structure of the system are discussed.The measured nonlinearity is discussed and analyzed.A silicon photoelectric detector is measured for many times.The repeated precision of measurement is prior to ±0.5 %.Measurement results prove the design of the system has high automation and precision.This system can be used as instrument of linear measurement of the photoelectric detectors.

Based on virtual instrument and auto-control principles,designed and developed an auto-measurement system of photoelectrical performance for OLED(Organic Light Emission Diode).The visible control and multithread synchronization train of thought and technology of embedded program for GPIB and PCI Dynamic link library are discussed.The key functions and orders are given and interpreted.After schemed,the system was tested and used in several laboratories.It's a powerful instrument for Optical-electrical parameter auto-measurement and the selection for OLED's material and composition.

Aiming at improving deficiencies of exposure meters that are available in the market, a thinning, miniaturizing and intellectualized exposure meter is developed. The system adopts single-chip computer of MSP430F449 as the MCU to control sampling and A/D conversion. And keys make it possible that the system have multimode working states, which consist of irradiation and exposure measuring. It also can store and read irradiation data in exposure measuring mode for later data analysis.

The measurement system of photoelectrical performance of OLED (Organic Light Emission Diode)is a powerful instrument for the development of organic light emission device. Based on Photometry and Auto-control principles,making good use of the advantages of Visual C ++ ,an automeasure system of photoelectrical performance for OLED is designed. The key principle,main framework and technology are discussed. After schemed,the system was used in several laboratories,made good result,got automatic accomplished and worked in high-speed. More development was indicated.

The Virtual instrument system of Auto-measure the characters of long time fluorescent material on Visual C++ platform is based on visible controlling system with computer.Based on virtual instrument and auto-control principles,designed and developed an auto-measure system of brightness performance for fluorescent material.The multithread synchronization train of thought and technology of embedded program for PCI Dynamic link library are discussed.The key functions and orders are given and interpreted.After schemed,the system was tested and used in several laboratories.It's a powerful instrument for brightness parameter auto-measurement and the selection for fluorescent material's composition.

The paper discusses the MScomm control's properties,events、communication mode and quotation, and illustrates an application instance of MScomm control in auto-measure control system.