- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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LAMOST CCD camera-control system based on RTS2
摘要： The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is the largest existing spectroscopic survey telescope, having 32 scientific charge-coupled-device (CCD) cameras for acquiring spectra. Stability and automation of the camera-control software are essential, but cannot be provided by the existing system. The Remote Telescope System 2nd Version (RTS2) is an open-source and automatic observatory-control system. However, all previous RTS2 applications were developed for small telescopes. This paper focuses on implementation of an RTS2-based camera-control system for the 32 CCDs of LAMOST. A virtual camera module inherited from the RTS2 camera module is built as a device component working on the RTS2 framework. To improve the controllability and robustness, a virtualized layer is designed using the master-slave software paradigm, and the virtual camera module is mapped to the 32 real cameras of LAMOST. The new system is deployed in the actual environment and experimentally tested. Finally, multiple observations are conducted using this new RTS2-framework-based control system. The new camera-control system is found to satisfy the requirements for automatic camera control in LAMOST. This is the first time that RTS2 has been applied to a large telescope, and provides a referential solution for full RTS2 introduction to the LAMOST observatory control system.
关键词： telescopes,methods: observational,techniques: imaging spectroscopy,instrumentation: detectors
更新于2025-09-19 17:15:36
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Mid-infrared interferometry with <i>K</i> band fringe-tracking
摘要： Context. A turbulent atmosphere causes atmospheric piston variations leading to rapid changes in the optical path difference of an interferometer, which causes correlated flux losses. This leads to decreased sensitivity and accuracy in the correlated flux measurement. Aims. To stabilize the N band interferometric signal in MIDI (MID-infrared Interferometric instrument), we use an external fringe tracker working in K band, the so-called FSU-A (fringe sensor unit) of the PRIMA (Phase-Referenced Imaging and Micro-arcsecond Astrometry) facility at VLTI. We present measurements obtained using the newly commissioned and publicly offered MIDI+FSU-A mode. A first characterization of the fringe-tracking performance and resulting gains in the N band are presented. In addition, we demonstrate the possibility of using the FSU-A to measure visibilities in the K band. Methods. We analyzed FSU-A fringe track data of 43 individual observations covering different baselines and object K band magnitudes with respect to the fringe-tracking performance. The N band group delay and phase delay values could be predicted by computing the relative change in the differential water vapor column density from FSU-A data. Visibility measurements in the K band were carried out using a scanning mode of the FSU-A. Results. Using the FSU-A K band group delay and phase delay measurements, we were able to predict the corresponding N band values with high accuracy with residuals of less than 1 μm. This allows the coherent integration of the MIDI fringes of faint or resolved N band targets, respectively. With that method we could decrease the detection limit of correlated fluxes of MIDI down to 0.5 Jy (vs. 5 Jy without FSU-A) and 0.05 Jy (vs. 0.2 Jy without FSU-A) using the ATs and UTs, respectively. The K band visibilities could be measured with a precision down to ≈2%.
关键词： instrumentation: interferometers,methods: observational,techniques: interferometric,methods: data analysis
更新于2025-09-19 17:15:36
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Feasibility of spectro-polarimetric characterization of exoplanetary atmospheres with direct observing instruments
摘要： Context. Spectro-polarimetry of reflected light from exoplanets is anticipated to be a powerful method for probing atmospheric composition and structure. Aims. We aim to evaluate the feasibility of the search for a spectro-polarimetric feature of water vapor using a high-contrast polarimetric instrument on a 30–40 m-class ground-based telescope. Methods. Three types of errors are considered: (a) errors from the difference between efficiencies for two orthogonally polarized states; (b) errors caused by speckle noises; and (c) errors caused by photon noise from scattered starlight. Using the analytically derived error formulas, we estimate the number of planets for which feasible spectro-polarimetric detection of water vapor is possible. Results. Our calculations show that effective spectro-polarimetric searches for water vapor are possible for 5 to 14 known planets. Spectro-polarimetric characterization of exoplanetary atmospheres is feasible with an extremely large telescope and a direct observing spectro-polarimeter.
关键词： instrumentation: polarimeters,techniques: polarimetric,planetary systems
更新于2025-09-19 17:15:36
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[IEEE 2018 11th Biomedical Engineering International Conference (BMEiCON) - Chiang Mai, Thailand (2018.11.21-2018.11.24)] 2018 11th Biomedical Engineering International Conference (BMEiCON) - Low-cost instrumentation of Automated Whole – slide Microscope for Biomedical Imaging
摘要： Microscope is one of the essential devices in medical profession. It is usually used for finding out types of abnormal cells or tissues, detecting the diseases, and defining a range treatment option for patient. Recently, there is a new technology of whole- slide imaging (WSI) which has been developed in the microscope. The technology provides the scanning of conventional glass slides to produce digital images of cumulative data. Since the WSI is a complex system and very expensive price, hence we aim to implement the prototype of a cost- effective whole – slide imaging system based on the principle of microscopic design. The implemented prototype consisting of optical and mechanical parts was developed using 3D printing. The optical system employed a 40x objective lens aligning with the digital camera for imaging the specimen on the standard slide. The mechanical system was designed for the movement of the slide in 3 dimensions controlled by stepper motors and microcontrollers based on controlling computer program. To accumulate the whole- slide image, the slide was scanned and captured in the X-Y axes and the focal (Z) axis in a sequence. The cumulative data was then analyzed and rendered the whole- slide image. The implemented device would be advantageous to cytologists and doctors for the biomedical imaging and recording numerous medical data of the patients.
关键词： Whole slide imaging,Biomedical imaging,Instrumentation,Microscope
更新于2025-09-19 17:15:36
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Research on the Application of Fast-steering Mirror in Stellar Interferometers
摘要： In stellar interferometers, the fast-steering mirror (FSM) is widely utilized to correct the wavefront tilt caused by the atmospheric turbulence and internal instrumental vibration, because of its high resolution and fast response frequency. In this study, the non-coplanar error between the FSM and the actuator deflection axis introduced by the manufacturing, assembly, and adjustment is analyzed systematically. Via a numerical method, the additional optical path difference (OPD) caused by the above factors is studied, and its effect on the fringe tracking accuracy of a stellar interferometer is also discussed. On the other hand, the starlight parallelism between the beams of two arms is one of the main factors for the loss of fringe visibility. By analyzing the influence of wavefront tilt caused by the atmospheric turbulence on fringe visibility, a simple and efficient real-time correction scheme of starlight parallelism is proposed based on a single array detector. The feasibility of this scheme is demonstrated by a laboratory experiment. The results show that after the correction of fast-steering mirror, the starlight parallelism meets preliminarily the requirement of a stellar interferometer on the wavefront tilt.
关键词： atmospheric effects,techniques: image processing,stars: imaging,instrumentation: interferometers,techniques: interferometric
更新于2025-09-19 17:15:36
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[IEEE 2018 2nd European Conference on Electrical Engineering and Computer Science (EECS) - Bern, Switzerland (2018.12.20-2018.12.22)] 2018 2nd European Conference on Electrical Engineering and Computer Science (EECS) - High-Speed Low-Power 4 Channel Laser Diode Driver for Pico-Projector Application
摘要： This paper presents a novel and analytical approach to identifying a lightning strike after it has struck an overhead transmission line. The identi?cation method is mainly based on the traveling waves’ time-domain parameters, such as polarity, amplitude, and half-wavelength. The main differences in these parameters across different strike types are analyzed. Subsequently, a robust identi?cation algorithm is proposed. An instrumentation system is implemented to verify the algorithm. The overall performances of the instrumentation system and the methodology are demonstrated using an on-site application with excellent results.
关键词： instrumentation system,current traveling wave,half-wave length,shielding failure,Back ?ashover,amplitude,polarity
更新于2025-09-16 10:30:52
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Simulation and in vivo investigation of LED-NIR Gaussian beam profile
摘要： Near infrared spectroscopy is an optical imaging technique which offers a non-invasive, portable, and low-cost method for continuously measuring the oxygenation of tissues. In particular, it can provide the brain activation through measuring the blood oxygenation and blood volume in the cortex. Understanding and then improving the spatial and depth sensitivity of near infrared spectroscopy measurements to brain tissue are essential for designing experiments as well as interpreting research findings. In this study, we investigate the effect of applying two common light beam profiles including Uniform and Gaussian on the penetration depth of an LED-based near infrared spectroscopy. In this regard, two Gaussian profiles were produced by adjusting plano-convex and bi-convex lenses and the Uniform profile was provided by applying a flat lens. Two experiments were conducted in this study. First, a simulation experiment was carried out based on scanning the intra space of a liquid phantom by using static and pulsating absorbers to compare the penetration depth of the configurations applied on the LED-based near infrared spectroscopy with that of a laser-based near infrared spectroscopy. Second, to show the feasibility of the best proposed configuration applied, an in vivo experiment of stress assessment has been performed and its results have been compared with that results obtained by laser one. The results showed that the LED-based near infrared spectroscopy equipped with bi-convex lens provides a penetration depth and hence quality measurements of near infrared spectroscopy and its extracted heart rate variability signals as well as laser-based near infrared spectroscopy especially in the application of stress assessment.
关键词： Biomedical optic,instrumentation,stress assessment,near infrared spectroscopy,optical sensors
更新于2025-09-12 10:27:22
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Recoil-ion momentum spectroscopy for cold rubidium in a strong femtosecond laser field
摘要： In this study, a new magneto-optical trap (MOT) recoil ion momentum spectrometer is built for investigating the interactions between cold rubidium (Rb) atoms and strong laser fields. This compact device can provide cold Rb in three different modes: 2D MOT mode, in which the beam generated by a two-dimensional MOT is pushed directly to the interaction regime; molasses mode, in which cooling lasers are applied at the interaction regime; and 3D MOT mode, in which a quadrupole magnetic field is applied to form a three-dimensional MOT. The typical densities of the three target modes are estimated to be 107, 108, and 109 atoms/cm3, respectively. Switching between the target modes is expected to provide a broad range of laser intensities with reasonable count rates while avoiding space charge effects. A single photoionization experiment serves as a benchmark test of the recoil ion momentum resolution. The best resolution is estimated as an unprecedented 0.12 a.u. in the time-of-flight direction, demonstrating significant potential for strong field ionization dynamics using this technique.
关键词： Ionization and excitation processes,Instrumentation and methods for time-of-flight (TOF) spectroscopy
更新于2025-09-11 14:15:04
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Spectroscopy of High-Intensity Bremsstrahlung Using Compton Recoiled Electrons
摘要： Recoiled Compton electrons of 180 deg have been utilized to measure the energy distribution of high-intensity bremsstrahlung. An optimized detector-collimator configuration was used for detection and spectrum measurement of recoiled electrons. The spectrum has been reconstructed using Compton cross sections retrieved from the ENDF/B.VIII.0 library. The measured spectrum has been further validated using theoretical simulation by the Geant4 code with incorporating ENDF/B-VIII.0–recommended cross sections. The simulated spectrum matches the measured spectrum if the spatial spread and energy spread of the electron beam are accounted for in the simulations.
关键词： Bremsstrahlung spectroscopy,Compton scattering,Geant4,nuclear instrumentation
更新于2025-09-11 14:15:04
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Low-frequency Raman spectrophotometer with wide laser illumination on the sample: A tool for pharmaceutical analytical analysis
摘要： This work describes an optical configuration for a Raman spectrophotometer, which permits variation of the laser spot size from 3 to 3000 μm, maintaining a high Raman photons throughput and allowing acquisitions with a short integration time. In addition, the instrument can acquire spectra from the low to middle frequency vibrational range (10 to 2000 cm-1), on the Stokes and anti-Stokes sides. One of the features of this new optical configuration is the non-use of beam splitters to redirect the scattered light to the detector, which would sacrifice the laser power. The quantitative and qualitative analytical performances of the Raman spectrophotometer were evaluated using chemometric models to predict the concentrations of different active pharmaceutical ingredients (APIs) in mixtures with polymorphs and excipients, as well as by analysis of an API mixture employing hyperspectral imaging. This new optical configuration was shown to be versatile for pharmaceutical purposes and could be used in applications such as the characterization of new drugs or the quality control of raw materials and processes, using normal Raman measurements or SERS (surface-enhanced Raman scattering).
关键词： Raman spectrophotometer,instrumentation,wide area illumination,low-frequency,paracetamol
更新于2025-09-11 14:15:04