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Degeneration of foundation cushion species induced by ecological constraints can cause massive changes in alpine plant communities 期刊论文  OAI收割
SCIENCE CHINA-LIFE SCIENCES, 2024, 卷号: 67, 期号: 3, 页码: 596-610
作者:  Chen, Jianguo;  Chen, Xufang;  Qian, Lishen;  Zhang, Yazhou;  Li, Bo
  |  收藏  |  浏览/下载：20/0  |  提交时间：2024/05/09
Cyanobacterial inoculation (cyanobacterisation): Perspectives for the development of a standardized multifunctional technology for soil fertilization and desertification reversal 期刊论文  OAI收割
EARTH-SCIENCE REVIEWS, 2017, 卷号: 171, 期号: 1, 页码: 28-43
作者:  Rossi, Federico;  Li, Hua;  Liu, Yongding;  De Philippis, Roberto
  |  收藏  |  浏览/下载：41/0  |  提交时间：2019/08/01
The altitudinal distribution center of a widespread cushion species is related to an optimum combination of temperature and precipitation in the central Tibetan Plateau SCI/SSCI论文  OAI收割
2013
作者:  Li R.
收藏  |  浏览/下载：22/0  |  提交时间：2014/12/24
Nanoscale patterns made by using a 13.5-nm Schwarzschild objective and a laser produced plasma source (EI CONFERENCE) 会议论文  OAI收割
Optical Micro- and Nanometrology IV, April 16, 2012 - April 18, 2012, Brussels, Belgium
作者:  Wang X.;  Wang X.;  Wang X.;  Wang Z.;  Wang Z.
收藏  |  浏览/下载：37/0  |  提交时间：2013/03/25
Lithium fluoride (LiF) crystal is a very promising candidate as nanometer resolution EUV and soft X-ray detector. Compared with other EUV and soft X-ray detectors  charge coupled device and photographic films  LiF crystal has high resolution  large field of view and wide dynamic range. In this paper  using LiF crystal as EUV detector and a Schwarzschild objective (SO) working at 13.5nm as projection optics  mesh images with 4.2 m  1.2 m and 800 nm line width and pinhole patterns with 1.5m diameter are acquired in projection imaging mode and direct writing mode  respectively. Fluorescence intensity profiles of images show that the resolution of mesh image is 900 nm  and the one of pinhole image is 800 nm. In the experiments  a spherical condense mirror based on normal incidence type is used to eliminate the damage and contamination on the masks (mesh and pinhole) caused by the laser plasma  and the energy density is not decreased compared with that the masks are close to the plasma. The development of the SO  the alignment of the objective and the imaging experiments are also reported. 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  
The sequence measurement system of the IR camera (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者:  Zhang H.-B.;  Han H.-X.;  Geng A.-H.
收藏  |  浏览/下载：36/0  |  提交时间：2013/03/25
Currently  the IR cameras are broadly used in the optic-electronic tracking  optic-electronic measuring  fire control and optic-electronic countermeasure field  but the output sequence of the most presently applied IR cameras in the project is complex and the giving sequence documents from the leave factory are not detailed. Aiming at the requirement that the continuous image transmission and image procession system need the detailed sequence of the IR cameras  the sequence measurement system of the IR camera is designed  and the detailed sequence measurement way of the applied IR camera is carried out. The FPGA programming combined with the SignalTap online observation way has been applied in the sequence measurement system  and the precise sequence of the IR camera's output signal has been achieved  the detailed document of the IR camera has been supplied to the continuous image transmission system  image processing system and etc. The sequence measurement system of the IR camera includes CameraLink input interface part  LVDS input interface part  FPGA part  CameraLink output interface part and etc  thereinto the FPGA part is the key composed part in the sequence measurement system. Both the video signal of the CmaeraLink style and the video signal of LVDS style can be accepted by the sequence measurement system  and because the image processing card and image memory card always use the CameraLink interface as its input interface style  the output signal style of the sequence measurement system has been designed into CameraLink interface. The sequence measurement system does the IR camera's sequence measurement work and meanwhile does the interface transmission work to some cameras. Inside the FPGA of the sequence measurement system  the sequence measurement program  the pixel clock modification  the SignalTap file configuration and the SignalTap online observation has been integrated to realize the precise measurement to the IR camera. Te sequence measurement program written by the verilog language combining the SignalTap tool on line observation can count the line numbers in one frame  pixel numbers in one line and meanwhile account the line offset and row offset of the image. Aiming at the complex sequence of the IR camera's output signal  the sequence measurement system of the IR camera accurately measures the sequence of the project applied camera  supplies the detailed sequence document to the continuous system such as image processing system and image transmission system and gives out the concrete parameters of the fval  lval  pixclk  line offset and row offset. The experiment shows that the sequence measurement system of the IR camera can get the precise sequence measurement result and works stably  laying foundation for the continuous system. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  
Design of reimaging F/1.0 long-wavelength infrared optical system (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者:  Zhang X.;  Zhang X.;  Zhang X.
收藏  |  浏览/下载：36/0  |  提交时间：2013/03/25
A reimaging F/1.0 long-wavelength infrared optical system is proposed. The design has a flexible opto-mechanical layout. The design process is as follows. Firstly  the catadioptric reimaging system consists of two reflecting mirrors and a relay lenses. Two reflecting mirrors make up of the first imaging system and are therefore free of chromatic aberrations  while low dispersion lenses were used in the reimaging system  so the optical system do not need achromatic design for a high image quality. Then  to correct high-order aberrations resulting from large relative aperture  more parameters need to be used with aspheric or diffractive surfaces due to modern optic technology development. Here  aspheric is selected for easily manufacture. Finally  the design is completed with the help of ZEMAX software. The effective focal length of the objective is 120mm and the field of view (FOV) is 4. The simulated final design shows adequate image quality and the modulation transfer function (MTF) is close to diffraction limit. The effect of the surrounding environmental temperature is analyzed using the concept of thermal defocusing  and the thermal compensation is discussed. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  
The application of diagnostic equipment in the Tokamak fusion reaction (EI CONFERENCE) 会议论文  OAI收割
2011 International Conference on Optical Instruments and Technology: Optical Systems and Modern Optoelectronic Instruments, November 6, 2011 - November 9, 2011, Beijing, China
Zhang B.-S.; Chang J.; Gong X.-Z.; Gan J.-F.; Feng S.-L.
收藏  |  浏览/下载：18/0  |  提交时间：2013/03/25
This paper introduces the infrared optical system in the Tokamak fusion reaction device. In this optical system  3.the relay group lenses. This paper describes the decrease of the modulation transfer function (MTF) when the temperature changes and how to compensate the decrease of the MTF in order to maintain the image quality in a high level. As a result  the traditional optical structure can't meet the requirements  2.the Cassegrain system  the image quality of this optical system can reach the requirements when the temperature changes. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  because the length of the infrared optical system in the Tokamak is very long. The design of optical system in the detection facility includes three parts:1.the combination of the concave aspheric mirror and flat mirror  
Fabrication of high-efficiency ultraviolet blazed gratings by use of direct Ar2-CHF3 ion-beam etching through a rectangular photoresist mask (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Sensor and Micromachined Optical Device Technologies, May 24, 2011 - May 26, 2011, Beijing, China
Tan X.
收藏  |  浏览/下载：25/0  |  提交时间：2013/03/25
In ultraviolet spectroscopy  groove irregularity and surface roughness of nanometer magnitude can cause a significant loss of diffraction efficiency. Therefore  there is a constant need to improve the diffraction efficiency. A blazed grating can concentrate most of the light intensity into a desired diffraction order  it is important to control the groove shape precisely  so it is the optimum choice among gratings of different kinds of profile. As the operating wavelength of most UV spectral applications is less than 200 nm  especially the blaze angle and the apical angle. We have presented a direct shaping method to fabricate EUV blazed gratings by using an ion-beam mixture of Ar+ and CHF2 +to etch K9 glass with a rectangular photoresist mask. With this method  the required blaze angle is small  we have succeeded in fabricating well-shaped UV blazed gratings with a 1200 line/mm groove density and 8.54 blaze angles and 1200 line/mm groove density and 11.68 blaze angles  and the metrical efficiency is about 81% and 78%. The good performance of the gratings was verified by diffraction efficiency measurements. When one uses the etching model  the conditions on the ion-beam grazing incident angle and the CHF3partial pressure should be noted. Besides  since the etched groove shape depends on the aspect ratio of the photoresist mask ridge  if we wish to fabricate larger gratings with this method  we must improve the uniformity of the photoresist mask before ion-beam etching. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  
The new approach for infrared target tracking based on the particle filter algorithm (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者:  Sun H.;  Han H.-X.;  Sun H.
收藏  |  浏览/下载：60/0  |  提交时间：2013/03/25
Target tracking on the complex background in the infrared image sequence is hot research field. It provides the important basis in some fields such as video monitoring  precision  and video compression human-computer interaction. As a typical algorithms in the target tracking framework based on filtering and data connection  the particle filter with non-parameter estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were widely used. There are various forms of density in the particle filter algorithm to make it valid when target occlusion occurred or recover tracking back from failure in track procedure  but in order to capture the change of the state space  it need a certain amount of particles to ensure samples is enough  and this number will increase in accompany with dimension and increase exponentially  this led to the increased amount of calculation is presented. In this paper particle filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under the complex background. From these two perspectives that "adaptive multiple information fusion" and "with particle filter framework combining"  we expand the classic Mean Shift tracking framework.Based on the previous perspective  we proposed an improved Mean Shift infrared target tracking algorithm based on multiple information fusion. In the analysis of the infrared characteristics of target basis  Algorithm firstly extracted target gray and edge character and Proposed to guide the above two characteristics by the moving of the target information thus we can get new sports guide grayscale characteristics and motion guide border feature. Then proposes a new adaptive fusion mechanism  used these two new information adaptive to integrate into the Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm can compensate shortcoming of the particle filter has too much computation  and can effectively overcome the fault that mean shift is easy to fall into local extreme value instead of global maximum value.Last because of the gray and fusion target motion information  this approach also inhibit interference from the background  ultimately improve the stability and the real-time of the target track. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).  
The ship-borne infrared searching and tracking system based on the inertial platform (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者:  Li Y.;  Zhang H.;  Zhang H.;  Li Y.;  Li Y.
收藏  |  浏览/下载：38/0  |  提交时间：2013/03/25
As a result of the radar system got interferenced or in the state of half silent  it can cause the guided precision drop badly In the modern electronic warfare  therefore it can lead to the equipment depended on electronic guidance cannot strike the incoming goals exactly. It will need to rely on optoelectronic devices to make up for its shortcomings  but when interference is in the process of radar leading  especially the electro-optical equipment is influenced by the roll  pitch and yaw rotation  it can affect the target appear outside of the field of optoelectronic devices for a long time  so the infrared optoelectronic equipment can not exert the superiority  and also it cannot get across weapon-control system "reverse bring" missile against incoming goals. So the conventional ship-borne infrared system unable to track the target of incoming quickly  the ability of optoelectronic rivalry declines heavily.Here we provide a brand new controlling algorithm for the semi-automatic searching and infrared tracking based on inertial navigation platform. Now it is applying well in our XX infrared optoelectronic searching and tracking system. The algorithm is mainly divided into two steps: The artificial mode turns into auto-searching when the deviation of guide exceeds the current scene under the course of leading for radar.When the threshold value of the image picked-up is satisfied by the contrast of the target in the searching scene  the speed computed by using the CA model Least Square Method feeds back to the speed loop. And then combine the infrared information to accomplish the closed-loop control of the infrared optoelectronic system tracking. The algorithm is verified via experiment. Target capturing distance is 22.3 kilometers on the great lead deviation by using the algorithm. But without using the algorithm the capturing distance declines 12 kilometers. The algorithm advances the ability of infrared optoelectronic rivalry and declines the target capturing time by using semi-automatic searching and reliable capturing-tracking  when the lead deviation of the radar is great. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).