检索结果-南通市图书馆

Temporal variation of hemispheric solar rotation

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2012年第2期12卷 187-200页

作者： Jing-Lan Xie 1,2,Xiang-Jun Shi 1,2 and Jing-Chen Xu 1,21 National Astronomical Observatories /Yunnan Observatory,chinese academy of sciences,Kunming 650011,china 2 graduate university of chinese academy of sciences,beijing 1.004.,china National Astronomical Observatories/ Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China graduate university of chinese academy of sciences Beijing 100049 China

The daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from 1945 January 1 to 2010 December 31 are used to investi- gate the temporal variation of rotational cycle length through the continuous wavelet transformation analysis method. Auto-correlation function analysis of daily hemi- spheric sunspot numbers shows that the southern hemisphere rotates faster than the northern hemisphere. The results obtained from the wavelet transformation analysis are that no direct relationship exists between the variation trend of the rotational cy- cle length and the solar activity in the two hemispheres and that the rotational cycle length of both hemispheres has no significant period appearing at 11 yr, but has a sig- nificant period of about 7.6 yr. Analysis concerning the solar cycle dependence of the rotational cycle length shows that acceleration seems to appear before the minimum time of solar activity in the whole disk and the northern hemisphere, respectively. Furthermore, the cross-correlation study indicates that the rotational cycle length of the two hemispheres has different phases, and that the rotational cycle length of the whole disk as well as the northern and southern hemispheres, also has phase shifts with corresponding solar activity. In addition, the temporal variation of the north-south （N- S） asymmetry of the rotational cycle length is also studied. This displays the same variation trend as the N-S asymmetry of solar activity in a solar cycle, as well as in the considered time interval, and has two significant periods of 7.7 and 17.5 yr. Moreover, the rotational cycle length and the N-S asymmetry of solar activity are highly corre- lated. It is inferred that the northern hemisphere should rotate faster at the beginning of solar cycle 24.

关键词： Sun: activity - Sun: rotation - Sun: sunspot

Relationship between Surface Pollen and Modern Vegetation in Southwestern china

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2010年第2期7卷 176-186页

作者： PAN Tao DAI Erfu and WU Shaohong Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China graduate university of chinese academy of sciences BeO'ing 100049 China Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China

Based on the pollen data obtained from thirty-five surface soil samples and investigated vegetation data from seven plant quadrats,the quantitative relationship between surface soil pollen and modern vegetation are studied in the longitudinal range-gorge region (LRGR) in Southwestern china.R-values (referring to pollen assemblages) are calculated with pollen percentage and plant *** coefficients of similarity between pollen and vegetation are *** results show that the pollen assemblages on surface soil of all vegetation zones can basically represent the native vegetation,but the pollen assemblages are not fully according with the *** is due to the influencing factors including pollen preservation ability,pollen production,amount of exotic pollen and pollen *** pollen representation in surface soil is different in families and *** pollen of woody plants such as Pinus,Tsuga,Alnus,Fagus and Castanopsis are over-representative,but those of Quercus,Carpinus Myrica,Elaeocarpaceae,Ericaceae,Theaceae and Llex are underrepresentative;the pollen of herbaceous plants such as Artemisia and Rubiaceae are over-representative,while those of others including Gramineae and Araliaceae are *** R-values of the same taxon pollen in different vegetation zones are different,depending on their distances from the pollen *** coefficients of the similarity between plant communities and pollen assemblages are mostly over 70%,which indicate again that the surface soil pollen and spores assemblages can represent the *** is concluded that there is a good corresponding relationship between surface pollen assemblages and native vegetation in LRGR,and it is of great significance for reconstructing the past vegetation and paleoclimate using quantitative fossil pollen data in this region.

关键词： Longitudinal range-gorge region (LRGR) Pollen assemblage Vegetation R-value Coefficient of similarity

Variation properties of ionospheric eclipse factor and ionospheric influence factor

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第6期15卷 573-576页

作者： ZHAO Chunmei 1,2 *, YUAN Yunbin1, OU Jikun1 and CHEN Jinping3(1. Institute of Geodesy and Geophysics, chinese academy of sciences, Wuhan 430077, china 2. graduate School of chinese academy of sciences, beijing 100039, china 3. Department of Precision Instrument and Mechanology, Tsinghua university, beijing 100084, china) Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China graduate School of chinese academy of sciences Beijing 100039 China Department of Precision Instrument and Mechanology Tsinghua University Beijing 100084 China

The concepts and calculation methods of ionospheric eclipse factor (IEF) and ionospheric influence factor (IFF) are further illustrated. The temporal and spacial variation properties of IEF and IFF are studied, which shows that the properties are influenced by the geographic position and season. The possibility of improving the precision of using GPS data to determine ionospheric delay based on the above variation properties is also analysed.

关键词： GPS ionospheric eclipse factor ionospheric influence factor

A new principle of synthetic cascade utilization of chemical energy and physical energy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2005年第2期48卷 163-179页

作者： JIN hongguang1, hong Hui1,2, WANG Baoqun1,2, han Wei1,2 & LIN Rumou1,2 1. Institute of Engineering Thermophysics, chinese academy of sciences, beijing 100080, china 2. graduate School of the chinese academy of sciences, beijing 100039, china 1. Institute of Engineering Thermophysics Chinese Academy of Sciences 100080 Beijing China 2. graduate School of the chinese academy of sciences 100039 Beijing China

We propose a new principle of the cascade utilization of both chemical energy and physical energy in energy systems with the integration of chemical processes and thermal cycles. Particularly, a general equation of energy levels of substance, Gibbs free energy of chemical reaction and physical energy is explicitly founded. On the basis of this equation, a chemical-looping combustion and an indirect combustion are investigated. Furthermore, a mechanism of energy release, with the combination of decreasing the energy level of Gibbs free energy and upgrading the energy level of low or middle- temperature thermal energy, is clarified. The promising results obtained here establish a theoretical basis for the further investigation of multi-function systems in which energy and the environment are compatible, and create a new approach to improve the performance of traditional thermal cycles.

关键词： chemical energy, cascade utilization, exergy, energy conversion.

Analysis of a kind of quantum cryptographic schemes based on secret sharing

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9期52卷 1313-1316页

作者： ZhanG XingLan1 & JI DongYao2 1 College of Computer Science and Technology, beijing university of Technology, beijing 100124, china 2 State Key Laboratory of Information Security, graduate university of chinese academy of sciences, beijing 1.004., china College of Computer Science and Technology Beijing University of Technology Beijing 100124 China State Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100049 China

Recently, Yang et al. proposed a kind of quantum cryptographic schemes based on secret sharing. The main idea is drawn from the case, where any n participants who share a secret K can co-operate as K does. This process can be applied to encryption, authentication, signature and so on. Unfortunately, since there is no identity authentication of the share's holder, these schemes inherit the limitation of secret sharing in practice. If some participants do not follow the protocol, the protocol would be a failure at last. Moreover, these schemes encounter another serious attack. Any two participants can co-operate to defeat the schemes by sending different shares to the parties unknown to the distributor of the secret K, such that these parties can execute the protocol as well. The attack proves that it is not enough for quantum cryptographic schemes that only the secret key is secure.

关键词： quantum identity authentication quantum secure direct communication quantum signature secret sharing

Adaptive quasi-likelihood estimate in generalized linear models

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2005年第6期48卷 829-846页

作者： CHEN Xia & CHEN Xiru School of Mathematics and Statistics, Wuhan university, Wuhan 430072, china graduate School, chinese academy of Science, beijing 1.004., china 1. School of Mathematics and Statistics Wuhan University 430072 Wuhan China 2. graduate School Chinese Academy of Science 100049 Beijing China

This paper gives a thorough theoretical treatment on the adaptive quasilikelihood estimate of the parameters in the generalized linear models. The unknown covariance matrix of the response variable is estimated by the sample. It is shown that the adaptive estimator defined in this paper is asymptotically most efficient in the sense that it is asymptotic normal, and the covariance matrix of the limit distribution coincides with the one for the quasi-likelihood estimator for the case that the covariance matrix of the response variable is completely known.

关键词： generalized linear models, quasi likelihood estimate, adaptive estimate.

Clinical manifestations,diagnosis and long-term prognosis of adult autoimmune enteropathy:Experience from Peking Union Medical College Hospital

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第19期30卷 2523-2537页

作者： Mu-han Li Ge-Chong Ruan Wei-Xun Zhou xiao-Qing Li Sheng-Yu Zhang Yang Chen xiao-Yin Bai hong Yang Yu-Jie Zhang Peng-Yu Zhao Ji Li Jing-Nan Li Department of Gastroenterology Chinese Academy of Medical Sciences&Peking Union Medical College HospitalBeijing 100730China Department of Pathology Chinese Academy of Medical Scinences&Peking Union Medical College HospitalBeijing 100730China Department of Pathology Tianjin First Central HospitalNankai UniversityTianjin 300192China Affairs Office Chinese Academy of Medical Sciences&Peking Union Medical College Hospital(West campus)Beijing 100032China

BACKGROUND Autoimmune enteropathy(AIE)is a rare disease whose diagnosis and long-term prognosis remain challenging,especially for adult AIE *** To improve overall understanding of this disease’s diagnosis and *** We retrospectively analyzed the clinical,endoscopic and histopathological characteristics and prognoses of 16 adult AIE patients in our tertiary medical center between 2011 and 2023,whose diagnosis was based on the 2007 diagnostic *** Diarrhea in AIE patients was characterized by secretory *** common endoscopic manifestations were edema,villous blunting and mucosal hyperemia in the duodenum and *** blunting(100%),deep crypt lymphocytic infiltration(67%),apoptotic bodies(50%),and mild intraepithelial lymphocytosis(69%)were observed in the duodenal ***,there were other remarkable abnormalities,including reduced or absent goblet cells(duodenum 94%,ileum 62%),reduced or absent Paneth cells(duodenum 94%,ileum 69%)and neutrophil infiltration(duodenum 100%,ileum 69%).Our patients also fulfilled the 2018 diagnostic criteria but did not match the 2022 diagnostic criteria due to undetectable anti-enterocyte *** patients received glucocorticoid therapy as the initial medication,of which 14/16 patients achieved a clinical response in 5(IQR:3-20)*** were administered to 9 patients with indications of steroid dependence(6/9),steroid refractory status(2/9),or intensified maintenance medication(1/9).During the median of 20.5 months of followup,2 patients died from multiple organ failure,and 1 was diagnosed with non-Hodgkin’s *** cumulative relapse-free survival rates were 62.5%,55.6%and 37.0%at 6 months,12 months and 48 months,*** Certain histopathological findings,including a decrease or disappearance of goblet and Paneth cells in intestinal biopsies,might be potential diagnostic criteria for adult *** long-term prognosis is still unsatisfac

关键词： Autoimmune enteropathy Clinical manifestations Diagnostic criteria Pathological features Long-term prognosis

Field-based evidence for the enrichment of intrinsic antibiotic resistome stimulated by plant-derived fertilizer in agricultural soil

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2024年第1期135卷 728-740页

作者： Shihai Liu Ziming han Dong Zhu xiao Luan Liujie Deng Liping Dong Min Yang Yu Zhang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China State Environmental Protection Engineering Center for Harmless Treatment and Resource Utilization of Antibiotic Residues Khorgos 835007China university of chinese academy of sciences Beijing 100049China

Animal manures have been demonstrated to enhance antibiotic resistance in agricultural ***,little is known about the effects of plant-derived fertilizer on soil antibiotic ***,metagenomic sequencing was used to investigate the effects of a plantderived fertilizer processed from sugarcane and beet on soil antibiotic resistance genes(ARGs)in a soybean field along crop growth *** profiles in the soils amended by plant-derived fertilizer were compared with those in the soils amended by chicken *** abundance and diversity of total ARGs in the soils amended by plant-derived fertilizer were significantly(Phan in unamended soils at the sprout stage of soybean were considered as enriched *** in the abundance of the enriched ARGs was observed in both the amended soils from the sprout to the *** analysis further identified Proteobacteria and Bacteroidetes as the primary bacterial taxa involved in the temporal variation of the enriched ARGs in the soils amended by plant-derived fertilizer,while in manured soils were Firmicutes and *** revealed by multivariate statistical analyses,variation of the enriched ARGs in the soils amended by plant-derived fertilizer was majorly attributed to the response of co-occurred bacteria to depleting nutrients,which was different from the failed establishment of manure-borne bacteria in the manured *** study provided field-based evidence that plant-derived fertilizer stimulated the intrinsic antibiotic resistome,and proposed attention to the un-perceived risk since some clinically relevant ARGs originate and evolve fr

关键词： Organic fertilizer Intrinsic antibiotic resistance Indigenous bacteria Metagenomic sequencing

Genetic differentiation of Wolffia globosa in china

在线全文

学校读者我要写书评

暂无评论

Journal of Systematics and Evolution 2011年第6期49卷 509-517页

作者： 1,2Jun-Xia YUAN 1Jin PAN 1Bao-Sheng WANG 1Da-Ming ZhanG 1(State Key Laboratory of Systematic and Evolutionary Botany,Institute of Botany,chinese academy of sciences,beijing 100093,china) 2(graduate university of chinese academy of sciences,beijing 1.004.,china) (State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing 100093 China) (graduate university of chinese academy of sciences Beijing 100049 China) *Correspondence: Da-Ming ZhanG *Correspondence: E-mail: zhangdm@*** Tel.: 86-10-62836492 Fax: 86-10-62590843.

Wolffia Horkel ex Schleid.(Lemnaceae) includes the world’s smallest ***,their bodies are extremely simplified,making classification difficult and *** reports about the genetic structure of these clonal-dominant aquatic plants have been published until *** this study,of 247 samples from 42 populations spanning representative locations in china,two chloroplast haplotypes(glo-cp and un-cp) and 66 amplified fragment length polymorphism genotypes were *** on wide sampling,cpDNA haplotypes,and amplified fragment length polymorphism profiles,we found that there are two genetic lineages(glo-and unlineages) of Wolffia species in *** and genetic diversity of Wolffia species are high compared with other clonal plants(Simpson’s index,D = 0.97;Nei’s diversity,H = 0.1835).Different spatial structure patterns were detected between glo-and *** autocorrelation at short distances(1500 km) were detected within the glo-lineage,but no significant spatial genetic structure was detected beyond 100 km within the ***,spatial genetic analysis of *** revealed significant autocorrelation within short distances,indicating that restricted gene flow might be one of the most important factors in shaping genetic structure.

关键词： AFLP chloroplast DNA genetic differentiation spatial genetic structure Wolffia.