中国科学院机构知识库网格系统: 检索

The Evolution of Life Modes in Stictidaceae, with Three Novel Taxa 期刊论文 OAI收割
JOURNAL OF FUNGI, 2021, 卷号: 7, 期号: 2, 页码: 105
作者: Thiyagaraja,Vinodhini; Luecking,Robert; Ertz,Damien; Karunarathna,Samantha C.; Wanasinghe,Dhanushka N.

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3 new taxa ancestral character state analysis asexual morph Lecanoromycetes Ostropomyces sexual morph Sphaeropezia PHYLOGENETIC-RELATIONSHIPS GRAPHIDACEAE ASCOMYCOTA OSTROPALES ASCOMYCOTA MULTIPLE ORIGINS FUNGI GENERA STICTIS ORDER ODONTOTREMATACEAE CLASSIFICATION

Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文 OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者: HXMT

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Insight-HXMT Geant4 simulation Background observation Astrophysics - Instrumentation and Methods for Astrophysics Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.

A stable phylogeny for Dactylosporaceae 期刊论文 OAI收割
CRYPTOGAMIE MYCOLOGIE, 2019, 卷号: 40, 期号: 3, 页码: 23-44
作者: Ekanayaka, Anusha H.; Jones, E. B. Gareth; Hyde, Kevin D.; Zhao, Qi

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Apothecial ascomycetes Eurotiomycetes Pezizomycotina incertae sedis polyphyletic new order new species

A new algorithm for solving the best-fit sphere of optical aspherical surface (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Advances in Materials and Manufacturing, ICAMMP 2011, December 16, 2011 - December 18, 2011, Guilin, China
作者: Lin J.; Lu M.

收藏 | 浏览/下载：40/0 | 提交时间：2013/03/25

To solve the best-fit sphere (BFS) accurately is one of the technological keys for the generating and testing of optical aspherical surfaces. This paper presents a new algorithm for solving the BFS of aspherical surfaces to suppress some deficiencies in the existing BFS algorithms. In the proposed approach it is not only suitable for the conic surface a BFS is constructed but also for higher order aspheres. The obtained asphericity and material removal function is more suitable for the machining and test. (2012) Trans Tech Publications which passes through both sides of endpoints in the section o -?xy of the aspherical surfaces Switzerland. the center of the BFS is shifted along the x-axis and its radius of curvature is automatically computed. The variable step size method is proposed to speed up the convergence of the iteration. Through numerically solving the BFS of conic and cubic surface the advantages of the proposed approach are verified. The results show that the proposed approach is of rapid convergence and high accuracy

Application of adaptive enhancement means in head and neck CR image (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Information Technology for Manufacturing Systems, ITMS 2012, September 8, 2012 - September 9, 2012, Qingdao, China
Zhang M.-H.; Zhang Y.-Y.

收藏 | 浏览/下载：37/0 | 提交时间：2013/03/25

Digital CR of head and neck overcomes the disadvantage of regular X-ray radiography which can not reveal bone and soft tissue position deficiency in one exposing and reduces the Xray radiation dose. Meanwhile various factors cause the decline of image quality and images must be enhanced in order to meet demands of doctor's clinical diagnosis. The general enhancement algorithms don't consider body's structure differences and density characteristics. A new adaptive CR enhancement algorithm was proposed in this article and head and neck CR images were processed with this method and compared with linear unsharp masking method. The experiment proves that the details of CR image enhanced were abundant and enhanced CR image had good visual effect SNR was high as well as detail variance /background variance (DV/BV) indicating that this algorithm is suitable for head and neck CR medical images. (2012) Trans Tech Publications Switzerland.

Design of the real-time autofocusing system for collimator with long focus length and large aperture (EI CONFERENCE) 会议论文 OAI收割
2011 International Academic Conference on Numbers, Intelligence, Manufacturing Technology and Machinery Automation, MAMT 2011, December 24, 2011 - December 25, 2011, Wuhan, China
作者: Zhang X.; Zhang X.; Zhang X.

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Large aperture collimator which has been widely used for calibrating and testing various optical devices plays an essential role in correlative laboratories. As being the basic testing and calibration equipment the large aperture collimator's accuracy should be much higher than the device under testing in order to ensure the accuracy of the measurement. However the process of adjusting the collimator is extremely complicated due to the collimator's large aperture and long focal length. So it is difficult to ensure the measurement's quality and easy to cause the system being vulnerable to the surrounding environment. One of the most common problems is defocus. In order to solve the problem above this issue presents a new type of autocollimator autofocusing system which uses pentaprism instead of using large-aperture plane mirror semiconductor lasers as light source and CCD sensor as receiver. The system is smaller lighter and more convenient when using. The computer simulation shows that the autofocusing system's resolution could reach the accuracy of 40m. If we use the relevant algorithms to execute the sub-pixel scanning the resolution could reach the accuracy of 10m. It shows that the system could satisfy the required testing precision of testing large aperture optical device.

Design and experimental research of a new type focus mechanism used in space-based telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Wang D.

收藏 | 浏览/下载：37/0 | 提交时间：2013/03/25

The position of focal plane will be changed because of temperature fluctuation and vacuum environment. In order to make the telescope work well positioning accuracy of the mechanism is 0.008mm. The performance satisfies the need of precision a focusing mechanism is needed. To majority of large space-based telescopes and the scheme design is reasonable and practicable. 2012 IEEE. the general way to do this would be to use a reflector which was located in the backfocal distance. One of typical schemes of this mechanism was introduced however because of the big axial size the mechanism can't be used when the size of the enclosure was limited. A new type of focusing mechanism was introduced which has such advantages of small size high accuracy and low mass. The design and test methods had been discussed. According to the results the repeatability positioning accuracy is 0.0025mm

Design of motion adjusting system for space camera based on ultrasonic motor (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
作者: Sun Z.

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Drift angle is a transverse intersection angle of vector of image motion of the space camera. Adjusting the angle could reduce the influence on image quality. Ultrasonic motor (USM) is a new type of actuator using ultrasonic wave stimulated by piezoelectric ceramics. They have many advantages in comparison with conventional electromagnetic motors. In this paper some improvement was designed for control system of drift adjusting mechanism. Based on ultrasonic motor T-60 was designed the drift adjusting system which is composed of the drift adjusting mechanical frame the ultrasonic motor the driver of Ultrasonic Motor the photoelectric encoder and the drift adjusting controller. The TMS320F28335 DSP was adopted as the calculation and control processor photoelectric encoder was used as sensor of position closed loop system and the voltage driving circuit designed as generator of ultrasonic wave. It was built the mathematic model of drive circuit of the ultrasonic motor T-60 using matlab modules. In order to verify the validity of the drift adjusting system was introduced the source of the disturbance and made simulation analysis. It designed the control systems of motor drive for drift adjusting system with the improved PID control. The drift angle adjusting system has such advantages as the small space simple configuration high position control precision fine repeatability self locking property and low powers. It showed that the system could accomplish the mission of drift angle adjusting excellent. 2011 SPIE.

The research on statistical properties of TDI-CCD imaging noise (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Gu Y.-Y.; Shen X.-H.; He G.-X.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

TDI-CCD can improve the sensitivity of space camera without any degradation of spatial resolution which is widely used in aerospace imaging devices. The article describes the basic working principle and application characteristics of TDI-CCD devices analyses the composition of TDI-CCD imaging noise and propose a new method to analyze TDI-CCD imaging noise with statistical probability distribution. In order to estimate the distribution of gray values affect by noise we introduced the concept of skewness and kurtosis. We design an experiment using constant illumination light source take image with TDI-CCD working at different stage such as stage 16 stage 32 stage 48 stage 64 and stage 96 analyse the characteristics of image noise with the method we proposed experimental results show that the gray values approximately meet normal distribution in large sample cases. 2011 SPIE.

Reality Sim: A realistic environment for robot simulation platform of humanoid robot (EI CONFERENCE) 会议论文 OAI收割
5th International Conference on Automation, Robotics and Applications, ICARA 2011, December 6, 2011 - December 8, 2011, Wellington, New zealand
作者: Fu Y.

收藏 | 浏览/下载：38/0 | 提交时间：2013/03/25

As a virtual training testing and evaluating environment simulation platform becomes a significant component in Soccer Robot project. Nevertheless the simulated environment in a simulation platform usually has a big gap with the realistic world. In order to solve this issue we demonstrate a more realistic simulation system which is called Reality Sim with numerous real images. By this system the computer vision code could be easily tested on simulation platform. For this purpose previously an image database with a large quantity of images recorded by camera pose is built. Furthermore if the camera pose of an image is not included in the database an interpolation algorithm is used to reconstruct a brand-new realistic image of that pose such that a realistic image could be provided on every robot camera pose. Our results show this system effectively simulates a more realistic environment for simulation platform. 2011 IEEE.