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Constraints on covariant Horava-Lifshitz gravity from precision measurement of planetary gravitomagnetic field 期刊论文  OAI收割
CHINESE PHYSICS C, 2025, 卷号: 49, 期号: 2, 页码: 9
作者:  
Zhang LD(张立冬);  Li LF(李丽仿);  Xu P(徐鹏);  Bian X(边星);  Luo ZR(罗子人)
  |  收藏  |  浏览/下载:7/0  |  提交时间:2025/02/17
食用蔬菜能吸收和积累微塑料 期刊论文  OAI收割
科学通报, 2019, 卷号: 64, 期号: 9, 页码: 928-934
作者:  
李连祯;  周倩;  尹娜;  涂晨;  骆永明
  |  收藏  |  浏览/下载:147/0  |  提交时间:2020/06/17
微塑料  生菜  聚苯乙烯微球  吸收  积累  健康风险  microplastics  lettuce  polystyrene microbeads  uptake  accumulation  human health risk  Microplastic (MP, 100 nm-5 mm) may present an attributable risk to ecosystem and human health, and its pollution has become a global environmental concern. Despite a wealth of information on the accumulation of MPs in aquatic species, there is no information on the uptake and accumulation of MPs by higher plants. Terrestrial edible plants are directly exposed to MPs when agricultural soil was applied with organic manure, sewage sludge as fertilizer or plastic mulching. In this paper, the uptake of two sizes of polystyrene (PS) microbeads (0.2 and 1.0 mum) and then their distribution and migration in an edible plant lettuce were firstly investigated based on laboratory experiments. We used fluorescent markers to track PS microbeads in plant tissues and found fluorescence to be a sensitive and reliable detection method. Sections from untreated control lettuce showed no autofluorescence. When roots were treated with fluorescently labeled PS microbeads, the microbeads could be identified by its fluorescence. Our main study investigated the uptake of 0.2 mum beads, as few luminescence signals were observed in lettuce roots for 1.0 mum beads in our experiment. We observed that 0.2 mum fluorescent microbeads were extracellularly trapped in the root cap mucilage (which is a highly hydrated polysaccharide) and a dark green tip (which was typical of lettuce roots exposed to label PS beads) was usually visible to the naked eye. Confocal images revealed that the PS luminescence signals were mainly located in the vascular system and on the cell walls of the cortex tissue of the roots, indicated that the beads passed through the intercellular space via the apoplastic transport system. Once inside the central cylinder, the 0.2 mum PS beads were transferred from the roots to the stems and leaves via the vascular system following the transpiration stream. We also observed that the PS beads adhered to one another and self-assembled systematically into grape-like and (chain) string-like clusters in the intercellular space of the root and stem vascular tissue of lettuce plant. In contrast to the root and stem, PS beads were dispersed in the leaf tissue. Here, for the first time we provide evidence of the adherence, uptake, accumulation, and translocation of submicrometer MPs within an edible plant. Our findings highlight the previously underappreciated human exposure pathway to MPs through the consumption of contaminated crops and emphasize the need for new management strategies to control the release of MPs waste products into the terrestrial environment. Ultimately, the potential impacts of low range sized MPs on food safety of crop plants and human health need to be urgently considered.  
A line mapping based automatic registration algorithm of infrared and visible images 会议论文  OAI收割
5th International Symposium on Photoelectronic Detection and Imaging (ISPDI) - Infrared Imaging and Applications, Beijing, June 25-27, 2013
作者:  
Ai R(艾锐);  Shi ZL(史泽林);  Xu DJ(徐德江);  Zhang CS(张程硕)
收藏  |  浏览/下载:38/0  |  提交时间:2013/12/26
There exist complex gray mapping relationships among infrared and visible images because of the different imaging mechanisms. The difficulty of infrared and visible image registration is to find a reasonable similarity definition. In this paper, we develop a novel image similarity called implicit linesegment similarity(ILS) and a registration algorithm of infrared and visible images based on ILS. Essentially, the algorithm achieves image registration by aligning the corresponding line segment features in two images. First, we extract line segment features and record their coordinate positions in one of the images, and map these line segments into the second image based on the geometric transformation model. Then we iteratively maximize the degree of similarity between the line segment features and correspondence regions in the second image to obtain the model parameters. The advantage of doing this is no need directly measuring the gray similarity between the two images. We adopt a multi-resolution analysis method to calculate the model parameters from coarse to fine on Gaussian scale space. The geometric transformation parameters are finally obtained by the improved Powell algorithm. Comparative experiments demonstrate that the proposed algorithm can effectively achieve the automatic registration for infrared and visible images, and under considerable accuracy it makes a more significant improvement on computational efficiency and anti-noise ability than previously proposed algorithms.  
Study on spectrograph for ionosphere: A broadband imaging instrument prototype for far-ultraviolet (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:  
Wang S.-R.;  Lin G.-Y.;  Yu L.
收藏  |  浏览/下载:37/0  |  提交时间:2013/03/25
Current research on space-based exploration for the ionosphere needs more advanced technologies. Because the spectral signals in the ionosphere distributing basically in the far-ultraviolet waveband are very weak. Usual spectrometer structures and detectors such as CCD can't receive enough information. Based on this principle of atmospheric sounding  the imaging spectrometer prototype for ionosphere detection application was designed to solve the problem. This prototype consists of the telescope and the imaging spectrometer. The simple structure and small number of mirrors can help higher transmission efficiency be achieved and weak signals detection be implemented. The telescope is an off-axis parabolic mirror and the spectrometer is a modified Czerny-Turner spectral imaging system. Modified Czerny-Turner spectrometer contains a spherical mirror  a fixed plane grating and a toroidal mirror. By adjusting the incident angle to the collimating mirror and using toroidal mirror  coma and astigmatism were corrected well. We also optimize distances between the grating to the focusing mirror and the focusing mirror to the image plane to improve disadvantages of traditional Czerny-Turner structure. Designed results demonstrate that aberrations are substantially corrected  and high image quality can be obtained in broad waveband. The photon counting Wedge-Strip-Anode detector with micro-channel planes as the receiving plane is accepted for the instrument prototype. The other photon counting 2-D detector responding well for weak light such as Cross-Delay line detector and MAMA detector can also be used for detection. The calibration and performances testing system is made of a vacuum system  a deuterium lamp  a monochrometer and the instrument prototype. Results obtained from the experiment show that the spectral resolution is 2.4 nm and the spatial resolution is 80 m. The other calibration experiments are running. The technology of the spectrometer prototype is important for the research and applications of ionosphere remote sensing. 2011 SPIE.  
Design of VxWorks-based software architecture for space optical remote sensor (EI CONFERENCE) 会议论文  OAI收割
2011 International Conference on Electronic and Mechanical Engineering and Information Technology, EMEIT 2011, August 12, 2011 - August 14, 2011, Harbin, China
Tao Y.; Song K.
收藏  |  浏览/下载:38/0  |  提交时间:2013/03/25
In order to satisfy requirements of real time and parallel control for the space optical remote sensor and implement the high integration of software  a kind of VxWorks-based multitask software architecture was put forward. Firstly  the technological requirements of optical remote sensor were analyzed in detail and functions and performances of the optical remote sensor were fixed. Task that was based on each function of optical remote sensor was compartmentalized. Then  software architecture of optical remote sensor was designed. Finally  experiments were carried out and results verified the accuracy and feasibility of the software architecture. Test results showed that the software architecture satisfied the requirements of real time and parallel control for the space optical remote sensor  its functions and performances met the system design target perfectly  and the software architecture was applicable to the engineering application of space instrument. 2011 IEEE.  
An efficient color transfer method for fusion of multiband nightvision images (EI CONFERENCE) 会议论文  OAI收割
2009 International Conference on Information Engineering and Computer Science, ICIECS 2009, December 19, 2009 - December 20, 2009, Wuhan, China
作者:  
Xu S.
收藏  |  浏览/下载:21/0  |  提交时间:2013/03/25
An improved two-dimensional entropy method for star trail tracing in deep sky (EI CONFERENCE) 会议论文  OAI收割
ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China
作者:  
Wang Y.-J.;  Yao Z.-J.
收藏  |  浏览/下载:32/0  |  提交时间:2013/03/25
The trace of star trail is an important component of deep sky detection. The stars are low contrast targets  and their self-rotation will make their brightness change in cycle. Above all  the trail trace is vulnerable to the block and disturbance of other stars. Traditional one-dimensional maximum entropy thresholding algorithm is vulnerable to the noise  and the calculation of two-dimensional entropy methods is too large and takes too much time. This paper proposes an improved two-dimensional entropy threshold algorithm. We use recursion iteration method to eliminate the redundancy calculation  and reduce the size of two-dimensional histogram based on the deep sky stars characteristic  such as low contrast  fuzziness and the centralized histogram. We also combine our algorithm with the space trail trace model to forecast the star trace. Experiments results show  when the star are blocked or they turn dark  the method still can well extrapolate the star trace. Our method improves the capability of trailing the ebb and small star  and increases the precision of tracing. It is also robust to the noise  so there is a good application foreground for the method.  
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