检索结果-南通市图书馆

Possible effect of solar activity on variation of the tree-rings of a 500 a platycladus orientalis at the Mausoleum of Emperor Huang

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2009年第4期52卷 631-639页

作者： FENG Bo1,2.. han {2. 1 Xi’an Institute of Posts & Telecommunications,Xi’an 710061,{2..2..3} astronomical observatories,chinese academy of sciences,Beijing 100012..2. Xi’an Institute of Posts & Telecommunications Xi’an 710061 China national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

The variation of the tree-ring's index of a platycladus orientalis at the Mausoleum of Emperor Huang and of a long series of sunspots relative number during AD1470-1974 are analyzed by using the wavelet power spectrum method,and their variation characters are also discussed. It is determined that the tree-ring's variation has cycles of approximate 2..,11,93 and 150 a. Two data series are used for analyzing sunspot relative number(SSN) variation. First,the analysis of the annual average SSN during AD1700-1974 proved that variation cycles are about 11,50,and 93 a; then,the data during AD1465-1975 obtained from the decadal average SSN train over 7000 a reconstructed on the geomagnetic data is analyzed and its variation cycles are about 50,90,and 160 a. Besides the tree-rings cycle of 2.. a is commonly considered to be related to ENSO,while 11 a cycle is related to solar Schwabe cycle; in addition,it is possible that the cycles of 90 and150 a are likely to be related to solar Gleissberg cycle and Suess cycle. The correlations between them are possibly due to the effect of solar activity on the climate and additionally on the tree's growth.

关键词： tree-ring solar activity climate change wavelet spectrum

Possible triggering of solar activity to big earthquakes (Ms ≥ 8) in faults with near west-east strike in china

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2004年第2期47卷 173-181页

作者： han yanben1, GUO Zengjian1,2..WU Jinbing1,2.. MA Lihua1 1. {2..{2. observatories, chinese academy of sciences, Beijing 100012..6} 2..Earthquake Research Institute of Lanzhou, CSB, Lanzhou 73000, china Correspondence should be addressed to han yanben (email: hyb@***) 1. national astronomical {2. Chinese Academy of Sciences 100012 Beijing China 2..Earthquake Research Institute of Lanzhou CSB 73000 Lanzhou China

This paper studies the relationship between solar activity and big earthquakes (Ms≥8) that occurred in china and western Mongolia. It is discovered that the occurrence dates of most of the big earthquakes in and near faults with west-east strike are close to the maximum years of sunspot numbers, whereas dates of some big earthquakes which are not in such faults are not close to the maximum years. We consider that it is possibly because of the appearance of many magnetic storms in the maximum years of solar activity. The magnetic storms result in anomalies of geomagnetic field and then produce eddy current in the faults gestating earthquake with near west-east strike. Perhaps the gestated big earthquakes occur easily since the eddy current heats the rocks in the faults and therefore decreases the shear resistant intensity and the static friction limit of the rocks .

关键词： earthquake, solar activity, magnetic storm, eddy current.

A new method of ionospheric-free hybrid differential positioning based on a double-antenna CAPS receiver

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2009年第3期52卷 368-375页

作者： GUO JinYun1,2..han {2. & ChanG XiaoTao3 1 national {2. observatories, chinese academy of sciences, Beijing 100012..7} 2..ollege of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 2..510,{12. 3 chinese academy of Surveying and Mapping, Beijing 100039,{12. 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China 2..College of Geodesy and Geomatics Shandong University of Science and Technology Qingdao 266510 China 3. chinese academy of Surveying and Mapping Beijing 100039 China

chinese Area Positioning System (CAPS) is a transmitted satellite navigation system moved by the chinese academy of sciences. Three basic modes of navigation and positioning with CAPS are given, and then a comparative analysis is made in this paper. In terms of the principle that the ionospheric delay is at an inverse ratio to the frequency square, a new ionospheric-free positioning method based on a double-antenna CAPS receiver is put forward. Then the hybrid differential observations and the solving equations and algorithms for one epoch and multi epochs are deduced according to the basic principle of the method. The method may remove the global errors in signal emission, propagation, transmission and receiving (e.g., ionospheric delay, hardware delay, and clock error). So it is very convenient for the single-epoch solution and multi-epoch navigation and positioning, and may efficiently improve the precision of real time CAPS navigation. Furthermore, the method can be used not only for the geometric orbit determination of CAPS GEO and IGSO satellites and the navigation and positioning, but also for the estimation of the tropospheric zenith delay, which is useful for the study of water vapor c{{2.es in the atmosphere. Polynomials are used in this method to express the tropospheric zenith delay and CAPS satellite orbits within the limited time interval, which reduces the num- ber of unknown parameters and thus speeds the computation.

关键词： chinese Area Positioning System (CAPS) ionospheric-free linear combination double-antenna receiver hybrid differential positioning method

“Double dawn”eclipse and the rotational variation of the earth

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2000年第11期45卷 988-991页

作者： ZhanG Peiyu & han {2.. Purple Mountain Observatory, chinese academy of sciences, Nanjing 2..008,{2. 2..Beijing astronomical Observatory, chinese academy of sciences, Beijing 100012..national astronomical Observatory, chinese academy of sciences, Beijing 100012..4} Purple Mountain Observatory Chinese Academy of Sciences Nanjing China Beijing astronomical Observatory Chinese Academy of Sciences Beijing national astronomical Observatory Chinese Academy of Sciences Beijing China

A record of 'double dawn' at State Zheng in the first year of the reign of King Yi in Western Zhou Dynasty in the chronicle 'Bamboo Annals' (Zhushu Jinian) is discussed. We think that it may be a record of an annular solar eclipse happening in 899 BC. The record and the AT, which describes the secular variation of the earth’s rotation, are analyzed and discussed.

关键词： solar eclipse earth’s rotation.

Wavelet analysis of sunspot relative numbers

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2002年第7期47卷 609-612页

作者： han yanben & han yonggang{2. astronomical observatories, chinese academy of sciences, Beijing 100012..8} Department of Applied Mathematics, Beijing Polytechnic University, Beijing 10002.. china 1. national astronomical {2. Chinese Academy of Sciences 100012 Beijing China 2..Department of Applied Mathematics Beijing Polytechnic University 100022 Beijing China

The time series of the monthly smoothed sun-spot numbers in 1749-2..0 is analyzed with the wavelet. The result shows that besides the known time-variation of the period about 11 years, other main periods of the sunspot numbers, such as the periods of about 100 years and so on, vary with time. We suggest that the time-variation of the main periods is the manifestation of the complex variation of sunspot numbers. It is significant to make a thorough study of the character and mechanism of the time-variation of the periods for proving prediction of sunspot numbers, especially for understanding the variation process of sunspot numbers.

关键词： sunspot numbers prediction wavelet time-variation.

A study on volunteer augmentation navigation technology

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2011年第6期54卷 1029-1034页

作者： WU HaiTao 1,2..U XiaoChun 1,2..OU DeCai 1,2.. han Tao 1,2.. national Time Service Center,{2..{2. of sciences,Xi’an 710600,china 2..ey Laboratory of Precision Navigation and Timing Technology,{2..{2. of sciences,Xi’an 710600,china 1. national Time Service Center Chinese Academy of Sciences Xi’an 710600 China2. Key Laboratory of Precision Navigation and Timing Technology Chinese Academy of Sciences Xi’an 710600 China

Navigation augmentation technology is one of the most common methods to increase the continuity,reliability and integrity of the global satellite navigation *** concept of volunteer augmentation navigation (VNA) is proposed and the elements and topological structure of VNA are also analyzed in this *** study focuses on the neural network model that volunteers and ordinary users use modern communication information network to exchange self-organizing *** neural cell model of Volunteer Augmentation Navigation using shared information is *** interactive general relative positioning is *** basic theories and methods of volunteer augmentation navigation are formed on the basis of the above-mentioned *** study of realization mechanism of volunteer augmentation technology helps to form a relatively integral architecture of volunteer augmentation navigation.A user self-service satellite navigation augmentation which combines information exchange and navigation services may strengthen the continuity,reliability and integrity of the navigation *** volunteer augmentation navigation theory proposed in this paper improves the traditional satellite navigation application model and expands the connotation and denotation of satellite navigation augmentation methods.

关键词： volunteer augmentation navigation self-organizing information exchange interactive general relative positioning

Interaction mechanism of cyanide with pyrite during the cyanidation of pyrite and the decyanation of pyrite cyanide residues by chemical oxidation

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第9期31卷 1996-2005页

作者： Wenwen han Hongying Yang Linlin Tong Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819China School of Metallurgy Northeastern UniversityShenyang 110819China

The toxic cyanides in cyanide residues produced from cyanidation process for gold extraction are harmful to the *** is one of the main minerals existing in cyanide *** this work,the interaction of cyanide with pyrite and the decyanation of pyrite cyanide residue were *** revealed that high pH value,high cyanide concentration,and high pyrite dosage promoted the interaction of cyanide with *** cyanidation of pyrite was pseudo-second-order with respect to *** decyanation of pyrite cyanide residue by Na_(2..O_(3)/air oxidation was *** cyanide removal efficiency was 83.9% after 1 h of reaction time under the optimal conditions of pH value of 11.2..O_(3)^(2.. dosage of 2..mg·g^(-1),and air flow rate of 1.46 L·min^(-1).X-ray photoelectron spectroscopy analysis of the pyrite samples showed the formation of Fe(Ⅲ)and FeSO_(4) during the cyanidation *** cyanide that adsorbed on the pyrite surface after cyanidation mainly existed in the forms of free cyanide(CN^(-))and ferrocyanide(Fe(CN)_(6)^(4-)),which were effectively removed by Na_(2..O_(3)/air *** the decyanation process,air intake promoted pyrite oxidation and weakened cyanide adsorption on the pyrite *** study has practical significance for gold enterprises aiming to mitigate the environmental impact related to cyanide residues.

关键词： pyrite cyanide decyanation sodium sulfite/air oxidation cyanide residue

Improved Variable Forgetting Factor Proportionate RLS Algorithm with Sparse Penalty and Fast Implementation Using DCD Iterations

在线全文

学校读者我要写书评

暂无评论

china Communications 2024年第10期21卷 16-27页

作者： han Zhen Zhang Fengrui Zhang Yu han Yanfeng Jiang Peng GNSS Research Center Wuhan UniversityWuhan 430072China School of Information Science and Technology Shijiazhuang Tiedao UniversityShijiazhuang 050043China

The proportionate recursive least squares(PRLS)algorithm has shown faster convergence and better performance than both proportionate updating(PU)mechanism based least mean squares(LMS)algorithms and RLS algorithms with a sparse regularization *** this paper,we propose a variable forgetting factor(VFF)PRLS algorithm with a sparse penalty,e.g.,l_(1)-norm,for sparse *** reduce the computation complexity of the proposed algorithm,a fast implementation method based on dichotomous coordinate descent(DCD)algorithm is also *** results indicate superior performance of the proposed algorithm.

关键词： dichotomous coordinate descent proportionate matrix RLS sparse systems variable forgetting factor

High leaf area index expands the contrasting effect of climate warming on Western Siberia taiga forests activity before and after 2..0

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical sciences 2024年第1期34卷 131-145页

作者： SUN han WANG Xiangping State Key Laboratory of Efficient Production of Forest Resources Beijing Forestry UniversityBeijing 100083China School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China

The taiga vegetation in Western Siberia has been seriously threatened by climate warming in recent ***,how vegetation in different growing states and climate conditions responds to climate changes differently is still *** we explore the vegetation activity trends in Western Siberia taiga forests using the annual rate of change in leaf area index(LAI)during 198{2.018 so as to answer two questions:(1)how did climate warming affect taiga vegetation activity in the recent last decades?({2.id the growing state of taiga forest affect its response to climate warming?Our results revealed that climate warming promoted taiga vegetation activity in Western Siberia before ***,continuous warming caused excessive evapotranspiration and led to decreased vegetation activity after ***,the intensity of vegetation growth response to warming was positively related to canopy height and LAI,indicating that both the positive and negative effects of warming were more significant in taiga forests in better growing *** these forests generally have higher productivity and play more important roles in ecosystem functioning(e.g.,carbon sink and biodiversity conservation),our results highlight their vulnerability to future climate change that need more research attention.

关键词： climate warming taiga forest leaf area index(LAI) vegetation activity Western Siberia