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New multi-camera calibration algorithm based on 1D objects

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第6期9卷 799-806页

作者： Zi-jian ZHAO yun-cai LIU Institute of linage Processing and Pattern Recognition Shanghai Jiao Tong University Shanghai 200240 China

A new calibration algorithm for multi-camera systems using 1D calibration objects is proposed. The algorithm inte- grates the rank-4 factorization with zhang (2004)'s method. The intrinsic parameters as well as the extrinsic parameters are re- covered by capturing with cameras the 1D object's rotations around a fixed point. The algorithm is based on factorization of the scaled measurement matrix, the projective depth of which is estimated in an analytical equation instead of a recursive form. For more than three points on a 1D object, the approach of our algorithm is to extend the scaled measurement matrix. The obtained parameters are finally refined through the maximum likelihood inference. Simulations and experiments with real images verify that the proposed technique achieves a good trade-off between the intrinsic and extrinsic camera parameters.

关键词： Multi-camera calibration Homography Factorization Scaled measurement matrix Projective depth

Fluctuation of Picea timberline and paleoenvironment onthe northern slope of Tian-shan Mountains during the late Holocene

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Chinese Science Bulletin 2006年第14期51卷 1747-1756页

作者： zhang yun KONG Zhaochen YAN Shun YANG Zhenjing NI jian Laboratory of Quantitative Vegetation Ecology Institute of Botany Chinese Academy of Sciences Beijing 100093 China Xinjiang Institute of Ecology and Geography Chinese Academy ofSciences ürümqqi 830011 China Institute of Hydrologic and Environmental Geology Chinese Academy of Geological Sciences Zhengding 050803 China

As a good indicator of Holocene climate, the fluctuation of alpine timberline is a synthetical result of impacts of many environmental factors dur-ing geological and historical periods and modern times. As the dominant tree species of mountainous conifer forests on the northern slope of Tianshan Mountains in Xinjiang, the distribution of Picea schrenkiana and its population size are sensitive to climatic change. The typical natural profile of Huashuwozi and the nearby Xiaoxigou archaeologi-cal profile, located in Quanzijie Township, Jimusaer County in Xinjiang, were chosen to analyze and compare the relative high-resolution pollen records, and to measure 14C dating and SEM (scanning elec-tron microscope) microstructure for charcoal frag-ments contained in Xiaoxigou profile’s cultural layers. The results show that in these two profiles, the high percentages of Picea (more than 20% and 35%, re-spectively) appeared in the stratum of the same pe-riod (2000-1300 a BP), which corresponds to the charcoal fragment’s age of Picea schrenkiana con-tained in Xiaoxigou cultural layers. These results convincingly revealed that during the period of 2000-1300 a BP, the timberline for Picea schrenkiana on the northern slope of Tianshan Mountains in Xinjiang declined by about 330m compared with the present.

关键词：云杉属树木线天山北坡全新世

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基于多功能树木养护装置结构设计与应用

农机化研究 2025年第3期47卷 116-120页

作者：周启兴熊俊康张俭南昌交通学院南昌330100

以进一步提升绿化树木的养护效率为目标,选取多功能设计理念为切入点,针对树木养护作业的机械化装置展开研究。考虑养护树木环境作业特点及养护目标机理,基于机械设计方法与电机控制技术,搭建多功能树木养护装置的架构布局,针对定位功... 详细信息

以进一步提升绿化树木的养护效率为目标,选取多功能设计理念为切入点,针对树木养护作业的机械化装置展开研究。考虑养护树木环境作业特点及养护目标机理,基于机械设计方法与电机控制技术,搭建多功能树木养护装置的架构布局,针对定位功能、涂白功能和缠绕功能进行相应的装置结构设计。同时,展开树木养护作业试验,结果表明:基于多功能树木养护装置的结构设计方案正确可行,整机的涂白作业效率与缠绕作业效率分别可达95.85%和94.20%,树木涂白与保温缠绕均能满足较好的均匀性,作业过程定位转向精准,具有很好的普适性,可有效降低树木冻害损失,对于树木的养护方式和装置开发有一定参考价值。

关键词：绿化树木多功能设计养护装置涂白作业效率普适性

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Statistical analysis of ocular monochromatic aberrations in Chinese population for adaptive optics ophthalmoscope design

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Journal of Innovative Optical Health Sciences 2017年第1期10卷 84-93页

作者： Junlei Zha Fei Xiao jian Kang Haoxin Zhao yun Dai Yudong zhang The Laboratory on A daptive Optics Institute of Optics and Electronics Chinese A cademy of Sciences Chengdu 610209 P.R.China The Key Laboratory on Adaptive Optics Chinese Academy of Sciences Chengdu 610209 P.R.China University of Chinese Academy of Sciences Beijing 100049 P.R.China

It is necessary to know the distribution of the Chinese eye's aberrations in clinical environment to guide high-resolution retinal imaging system design for large Chinese population *** collected the monochromatic wave aberration of 332 healthy eyes and 344 diseased eyes in Chinese population across a 6.0-mm *** aberration statistics of Chinese eyes including healthy eyes and diseased eyes were analyzed,and some differences of aberrations between the Chinese and European race were *** this basis,the requirement for adaptive optics(AO)correction of the Chinese eye's monochromatic aberrations was *** result showed that a stroke of 20μm and ability to correct aberrations up to the 8th Zernike order were needed for reflective wavefront correctors to achieve near difraction-limited imaging in both groups for a reference wavelength of 550 nm and a pupil diameter of *** verify the:analysis mentioned above,an A0 floodillumination system was established,and high-resolution retinal imaging in vivo was achieved for Chinese eye including both healthy and diseased eyes.

关键词： Ocular aberrations adaptive optics retinal imaging.

Reverse-trace routing scheme in content centric networking

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The Journal of China Universities of Posts and Telecommunications 2013年第5期20卷 22-29页

作者： zhang Yan HUANG Tao LIU jiang CHEN jian-ya LIU yun-jie Key Laboratory of Universal Wireless Communications of Ministry of Education Beijing University of Posts and Telecommunications

Content center networking （CCN） is one of the most promising future network architectures. Current researches on CCN routing scheme mainly focus on finding the best single routing path, which may induce to low usage of the in-network caches. In order to overcome this problem, a reverse trace routing （RTR） scheme is proposed in this paper, in which Interest packet is sent to the edge-cache along with the reverse trace of the corresponding former Data packet. By doing this, the Interest packets will have better chances to be routed to the promising in-network caches before reaching the source server, which could increase the in-network hit rate, while decrease the server stress. The simulation results show clearly that the RTR scheme decreases the source server load, while reducing the mean hops of entire data retrieval process under certain circumstances.

关键词： CCN routing RTR next face table (NFT)

Pollen record and environmental evolution of Caotanhu wetland in Xinjiang since 4550 cal. a BP

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Chinese Science Bulletin 2008年第7期53卷 1049-1061页

作者： zhang yun KONG ZhaoChen NI jian YAN Shun YANG ZhenJing State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing 100093 China Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Institute of Hydrologic and Environmental Geology Chinese Academy of Geological Sciences Zhengding 050803 China

This paper presents a multi-proxy reconstruction of the climate change in Caotanhu wetland using pollen, phytolith and charcoal records, and the data of loss of ignition (LOI), grain size analysis, and susceptibility. Results reveal that between 4550 and 2500 cal. a BP, a dry climatic condition was not favorable for the accumulation of peat. Since 2500 cal. a BP, the climate became humid and the wetland developed with abundant freshwater aquatic plants, which contributed to peat accumulation. Never-theless, alternate periods of rain and dry climate occurred during that period. Between 2500 and 1810 cal. a BP (550 BC―140 AD), the climate was more humid than at present. A lot of emerged plants, such as Phragmites, Typha and Sparganium, and freshwater green algae grew in the wetland which was sur-rounded by desert-steppe vegetation composed mainly of Chenopodiaceae, Artemisia, Compositae and Thalictrum. However, from 1810 to 1160 cal. a BP (140―790 AD), the water level started to decrease and hydrophyte species reduced greatly, but some Phragmites still grew in the wetland and around it was desert vegetation with high proportion of Chenopodiaceae and Artemisia. Then from 1160 to 650 a BP (790―1300 AD), it entered a period of desert-steppe with abundant mesic and xerophytic plants. And a lot of aquatic plants prevailed in the wetland. Here, what is noticeable is that percentages of arboreal pollen, consisting mainly of Betula and Picea, increased greatly and reached a maximal value of 27.2%, in which, Betula percentages rose to 23.2%. Hence, it is reasonable to conclude that Betula grew in the highland of the wetland, or Picea timberline shifted downward resulting in the increase of percentages of Betula and Picea pollen, which were transported into the wetland by flood or wind. But since 650 cal. a BP, desert vegetation prevailed around the wetland again with dominant Chenopodiaceae and Ar-temisia, and the climate was similar to modern one. Despite some aquatic plants

关键词：花粉环境进化湿地多样性

A 30-year overview of sodium-ion batteries

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Carbon Energy 2024年第6期6卷 56-98页

作者： yun Gao Hang zhang jian Peng Lin Li Yao Xiao Li Li Yang Liu yun Qiao Shu-Lei Chou School of Environmental and Chemical Engineering Shanghai UniversityShanghaiChina College of Chemistry and Materials Engineering Wenzhou UniversityWenzhouZhejiangChina Institute for Superconducting and Electronic Materials University of WollongongWollongongNew South WalesAustralia

Sodium-ion batteries(NIBs)have emerged as a promising alternative to commercial lithium-ion batteries(LIBs)due to the similar properties of the Li and Na elements as well as the abundance and accessibility of Na *** of the current research has been focused on the half-cell system(using Na metal as the counter electrode)to evaluate the performance of the cathode/anode/*** relationship between the performance achieved in half cells and that obtained in full cells,however,has been neglected in much of this ***,the trade-off in the relationship between electrochemical performance and cost needs to be given more ***,systematic and comprehensive insights into the research status and key issues for the full-cell system need to be gained to advance its ***,this review evaluates the recent progress based on various cathodes and highlights the most significant challenges for full *** strategies have also been proposed to enhance the electrochemical performance of NIBs,including designing electrode materials,optimizing electrolytes,sodium compensation,and so ***,perspectives and outlooks are provided to guide future research on sodium-ion full cells.

关键词： commercial application electrode electrolyte sodium-ion full cell strategies

Comparative transcriptomic analysis of rat versus mouse cerebral cortex after traumatic brain injury

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Neural Regeneration Research 2021年第7期16卷 1235-1243页

作者： Meng-Shi Yang Xiao-jian Xu Bin zhang Fei Niu Bai-yun Liu Beijing Key Laboratory of Central Nervous System Injury Beijing Neurosurgical InstituteCapital Medical UniversityBeijingChina Beijing Key Laboratory of Central Nervous System Injury and Department of Neurosurgery Beijing Neurosurgical Institute and Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Nerve Injury and Repair Center of Beijing Institute for Brain Disorders BeijingChina China National Clinical Research Center for Neurological Diseases BeijingChina

The heterogeneity of traumatic brain injury(TBI)-induced secondary injury has greatly hampered the development of effective treatments for TBI *** common processes across species may be an innovative strategy to combat debilitating *** the present study, a cross-species transcriptome comparison was performed for the first time to determine the fundamental processes of secondary brain injury in Sprague-Dawley rat and C57/BL6 mouse models of TBI, caused by acute controlled cortical *** RNA sequencing data from the mouse model of TBI were downloaded from the Gene Expression Omnibus(ID: GSE79441) at the National Center for Biotechnology *** the rat data, peri-injury cerebral cortex samples were collected for transcriptomic analysis 24 hours after *** expressed gene-based functional analysis revealed that common features between the two species were mainly involved in the regulation and activation of the innate immune response, including complement cascades as well as Toll-like and nucleotide oligomerization domain-like receptor *** findings were further corroborated by gene set enrichment ***, transcription factor analysis revealed that the families of signal transducers and activators of transcription(STAT), basic leucine zipper(BZIP), Rel homology domain(RHD), and interferon regulatory factor(IRF) transcription factors play vital regulatory roles in the pathophysiological processes of TBI, and are also largely associated with *** findings suggest that targeting the common innate immune response might be a promising therapeutic approach for *** animal experimental procedures were approved by the Beijing Neurosurgical Institute Animal Care and Use Committee(approval No.201802001) on June 6, 2018.

关键词： cognitive impairment cross-species comparison gene set enrichment analysis inflammation innate immune neurodegenerative disease secondary injury transcription factor transcriptome traumatic brain injury

Laser cooling of CH molecule: Insights from ab initio study

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Chinese Physics B 2018年第10期27卷 276-282页

作者： Jie Cui jian-Gang Xu jian-Xia Qi Ge Dou yun-Guang zhang School of Science Xi＇an University of Posts and TelecommunicationsXi＇an 710121China

The feasibility of laser cooling a CH molecule is investigated theoretically by employing the ab initio method. The potential energy curves for the five ∧-S states and eight Ω states of CH are determined by the multi-reference configuration interaction with the Davidson corrections（MRCI＋Q） level of theory. The results agree well with the available experimental data and other theoretical values. Also, the permanent dipole moments and transition dipole moments of the CH molecule are calculated at the multi-reference configuration interaction（MRCI） level. We find highly diagonally distributed FranckCondon factors（f00 = 0.9950 and 0.9998） and branching ratios（R00 = 0.983 and 0.993） for the A^2△→ X2Π and C^2∑^＋→X^2Π transitions. Moreover, the values of suitable radiative lifetime τ of the A2 A and C^2∑^＋ states are evaluated to be9.64×10^-7 s and 2.02×10^-7 s, respectively, for rapid laser cooling. A scheme for laser cooling the CH molecule is designed. In the proposed cooling scheme, three wavelengths for A^2△→X^2Π and C^2∑^＋→X^2Π transitions are used, and the main pump lasers are λ00=430.86 nm and 313.45 nm, respectively. The feasibility of laser cooling the CH molecules is demonstrated for each of these schemes, and this study offers a theoretical basis for experimental research into preparation of cold CH molecules.

关键词： spectroscopic constants transition diople moments Franck-Condon factors laser cooling