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Temporal variation of hemispheric solar rotation

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 1,2. National Astronomical Observatories /Yunnan Observatory,chinese academy of {2.,Kunming 650011,china 2.Graduate University of chinese academy of {2.,beijing 100049,china National Astronomical Observatories/ Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Graduate University of chinese academy of {2. Beijing 100049 China

The daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from 1945 January 1 to 2.10 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 2..

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

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Identification of high-lipid producers for biodiesel production from forty-three green algal isolates in china

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Progress in Natural Science:Materials International 2011年第4期21卷 269-276页

作者： An-yue LIU~(1,2.,Wei CHEN~1,Ling-ling ZHENG~1,Li-rong SONG~1 1.State Key Laboratory of Freshwater Ecology and Biotechnology,Institute of Hydrobiology, chinese academy of {2.,Wuhan 430072.china 2.Graduate school,chinese academy of {2.,beijing 100049,china [a] State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China [b] Graduate school Chinese Academy of Sciences Beijing 100049 China

To identify some desirable algal strains for our future research and/or the production of algae-based biofuel,43 green algal strains were successfully isolated from chinese freshwaters,and then incubated in the laboratory bioreactors for the growth and oil accumulation *** a 15 d incubation experiment,the accumulations of their biomass and total lipids,together with the lipid productivities for these green algal strains were systematically investigated and *** indicated that the accumulations of biomass for the 43 algal strains ranged from 0.53 g/L to 6.07 g/L during the experiments,with the highest biomass of 6.07 g/L for green algae Scenedesmus *** lipid content for the tested algal strains varied from 2.%to 51%of the dry biomass at the end of cultivation *** algae Chlorella pyrenoidosa was one of the best oil producers based on our investigations,with the total lipid content of 51%of dry *** the growth rates and the accumulations of intracellular lipids into the consideration,10 strains were considered to have significant potential for biofuel *** addition,the lipid productivities of the selected strains were further investigated.

关键词： biofuel microalgae lipid accumulation

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Isotopic feature and uranium dating of the volcanic rocks in the Okinawa Trough

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中国科学：地球科学英文版 2006年第4期49卷 375-383页

作者： HUANG Peng1,2. LI Anchun1, HU Ningjing2.3, FU Yongtao1& MA Zhibang4 1. Institute of Oceanology, chinese academy of {2., Qingdao 2.6071, china 2. Graduate school of the chinese academy of {2., beijing 100039, china 3. Institute of Soil Science, chinese academy of {2., Nanjing 2.0008, china 4. Institute of Geology and Geophysics, chinese academy of {2., beijing 10002., china 1. Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China 2. Graduate school of the chinese {2. of sciences Beijing 100039 China 3. Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China 4. Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Volcanic rocks from the northern and middle Okinawa Trough were dated by ura- nium-series dating method. Differential fractions using magnetic procedure were designed to separate samples. New report on the ages and isotopic data of rocks in the northern trough (especially black pumice) was discussed. Based on the uranium dates and Sr-Nd isotopic ratio, magmatic evolution process of the Okinawa Trough was noted. Firstly, there have been wide silicic volcanic activities in the Okinawa Trough from late Pleistocene to present, and the volcanic rocks can be divided into three subgroups. Secondly, magma generally came from PREMA source area under the Okinawa Trough. Magmatic evolution in the northern trough was similar to the middle, but different to the south. Finally, volcanic activities indicated that opening of the southern Okinawa Trough did not happen due to the collision between Luson Arc and Eurasian Plate until the early Pleistocene.

关键词： Okinawa Trough, black pumice, uranium-series dating, Sr-Nd isotopic ratio, magmatic evolution.

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Estimating possible impact of human activity on the warm season temperature in beijing since the industrial era

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chinese Science Bulletin 2010年第16期55卷 1590-1593页

作者： QIN Li1,2.& ZHOU Xin1,2.1 Institute of Geology and Geophysics,chinese academy of {2.,beijing 10002.,china 2.Graduate University of chinese academy of {2.,beijing 100049,china Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of {2. Beijing China

Global surface temperature shows an increasing trend over the past 100 *** and natural factors have been invoked to explain this warming, but their relative contribution and the spatial variability remain *** on a 2.50-year temperature record from a stalagmite near beijing, we explore the possible impacts of human activity on the warm season temperature in beijing since the industrial era using the method of singular spectrum analysis (SSA).The results suggest that the warm season temperature in beijing under the natural forcing should have an overall decreasing trend for the past 130 years (1870 to 2.00 AD) with an amplitude of 0.45±0.84°C, while the instrumental record and stalagmite data show an increase of 1.08°*** imply that human activity would have caused an increase in the warm season temperature of beijing for about 1.53±0.84°C compared to its natural trends, from 1870 AD to 2.00 *** results also suggest that anthropogenic forcing began to significantly influence the temperature since 1870 AD, and the effect further intensified since 1915 AD.

关键词：人类活动北京温度工业时代季节温暖估计地表气温

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Nonlinear autoregressive models with heavy-tailed innovation

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Science china Mathematics 2005年第3期48卷 333-340页

作者： JIN Yang & AN Hongzhi school of Statistics, Renmin University of china, {2. 100872. china academy of Mathematics and Systems Science, chinese academy of sciences, {2. 100080, china Sch. of Statistics Renmin Univ. of China Beijing 100872 China Acad. of Mathematics and Syst. Sci. Chinese Acad. of Sci. Beijing 100080 China

In this paper, we discuss the relationship between the stationary marginal tail probability and the innovation's tail probability of nonlinear autoregressive models. We show that under certain conditions that ensure the stationarity and ergodicity, one dimension stationary marginal distribution has the heavy-tailed probability property with the same index as that of the innovation's tail probability.

关键词： nonlinear autoregressive model, innovation, tail probability.

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The features of gravity field and deep structure in western part of the South Yellow Sea

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chinese Science Bulletin 2000年第8期45卷 759-764页

作者： WANG Qianshen1 & AN Yulin1. Institute of Geophysics, chinese academy of {2., beijing 100101, china 2. chinese University of Geology, beijing 100083, china Institute of Geophysics Chinesc Academy of Sciences Beijing China chinese University of Geology Beijing China

The gravity data from the sea region to the west of 12.° E of the South Yellow Sea have been processed and the feature of gravity fields analyzed. An experience relationship formula on the filter wavelength and corresponding depth has been put forward. Combined with the geological and seismic data, the deep tectonic framework and structural characters as well as possible favourable prospecting district for hydrocarbon in the South Yellow Sea have been discussed and analyzed.

关键词： western part of the South Yellow Sea gravity field deep structure.

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Mechanism and Defense on Malicious Code

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Wuhan University Journal of Natural sciences 2005年第1期10卷 83-88页

作者： WEN Wei-ping 1,2.3, QING Si-han 1,2.31. Institute of Software, the chinese academy of {2., beijing 100080, china 2.Engineering Research Center for Information Security Technology, the chinese academy of {2., beijing 100080, china 3.Graduate school of the chinese academy of {2., beijing 100080, china Institute of Software the Chinese Academy of Sciences Beijing 100080 China

With the explosive growth of network applications, the threat of the malicious code against network security becomes increasingly serious. In this paper we explore the mechanism of the malicious code by giving an attack model of the malicious code, and discuss the critical techniques of implementation and prevention against the malicious code. The remaining problems and emerging trends in this area are also addressed in the paper.

关键词： malicious code attacking model mechanism defense system security network security

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2.2. Guideline for the management of hypertension in the elderly population in china

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Journal of Geriatric Cardiology 2024年第6期21卷 589-630页

作者： Hypertension Branch of chinese Geriatrics Society,beijing Hypertension Association,National Clinical Research Center of the Geriatric Diseases Qi HUA Li FAN Zeng-Wu WANG Jing LI 不详 Xuanwu Hospital Capital Medical UniversityBeijingChina chinese PLA General Hospital BeijingChina Fuwai Hospital Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Preamble Hypertension is one of the most common chronic diseases and the primary risk factor for stroke,myocardial infarction and even cardiovascular *** than half of the elderly population has high blood *** people are a unique group,and strategies for the prevention,diagnosis,evaluation,and treatment of hypertension in elderly individuals differ significantly from those in the general population.

关键词： hypertension prevention diagnosis

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Nonlinear interactions between gravity waves and background winds

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Progress in Natural Science:Materials International 2007年第6期17卷 639-644页

作者： Liu Xiao1,2.and Xu Jiyao1(1. State Key Laboratory for Space Weather, Center for Space Science and Applied Research, chinese academy of {2., beijing 100080, china 2. Graduate University of chinese academy of {2., beijing 100039, china) [a]State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China [b]Graduate University of chinese academy of {2. Beijing China

Using the nonlinear propagating gravity waves (GW) model in the two-dimensional compressible atmosphere and the linear GW theory, the process of GW propagation in different background winds, e.g. the direction of the background wind is opposite to (dead wind) or the same as (tail wind) the direction of the horizontal phase velocity of GW, is studied. The results show that the dead wind prolongs the vertical wavelength and accelerates GW propagation. Therefore, GW propagates up to a higher height becomes instable in a short time and eventually induces an inverse jet flow. Then, the vertical wavelength is becoming short due to the nonlinear interactions between GW and the inverse jet flow. The vertical wavelength and group velocity decrease after GW propagates into the tail wind. The initial instable time is delayed. Although most of GW is trapped in the instable region, some of GW propagates above the instable region. Compared with GW propagation in the tail wind, the nonlinear interactions between GW and the dead wind are also strong. In contrast, the linear GW theory predicts that GW can propagate freely in the dead wind. The vertical wavelength simulated by the nonlinear numerical model is different from that predicted by the linear theory greatly after GW propagates into the dead wind.

关键词： gravity waves background winds vertical group velocity vertical wavelength nonlinear interactions.

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Existence of unbiased estimate of regression parameters in simple linear EV models

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Science china Mathematics 2005年第7期48卷 915-928页

作者： LIU Jixue & CHEN Xiru Department of Statistics and Finance, University of Science and Technology of china, Hefei 2.002., china Department of Mathematics, Graduate {2. of chinese academy of sciences, beijing 100049, china Department of Statistics and Finance University of Science and Technology of China Hefei 230026 China Department of Mathematics Graduate School Chinese Academy of Sciences Beijing 100049 China

It is well known that for one-dimensional normal EV regression model X = x+ u,Y =α+βx+e, where x, u, e are mutually independent normal variables and Eu=Ee=0, the regression parameters a and β are not identifiable without some restriction imposed on the parameters. This paper discusses the problem of existence of unbiased estimate for a and β under some restrictions commonly used in practice. It is proved that the unbiased estimate does not exist under many such restrictions. We also point out one important case in which the unbiased estimates of a and β exist, and the form of the MVUE of a and β are also given.

关键词： EV regression model unbiased estimate identiflability.

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