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Effects of Periodic Temperature Changes on Stress Relaxation of Chemically Treated Wood 被引量:4
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作者 XieManhua ZhaoGuangjie 《Forestry Studies in China》 CAS 2004年第4期45-49,共5页
关键词 WOOD structural change chemical treatment periodic temperature change stress relaxation
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Wavelet analysis of quasi-3-year temperature oscillations in China in last 50 years, and predicted changes in the next 20 years 被引量:1
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作者 ChengHai Wang Jian Li XiaoGuang Xu 《Research in Cold and Arid Regions》 CSCD 2013年第6期755-766,共12页
The wavelet analysis method is used to analyze the annual and winter temperature data of 98 observation stations in China in eight climate zones during the last 50 years (1961-2009). The periodicities of temperature... The wavelet analysis method is used to analyze the annual and winter temperature data of 98 observation stations in China in eight climate zones during the last 50 years (1961-2009). The periodicities of temperature changes are investigated, and the possible temperature change trends in China in the next 20 years (2012-2029) are also predicted. Our results show that in the inter-annual temperature variability there are pervasive quasi-3- to quasi-4-year cycles, and these cycle changes are relatively steady. The periodic characteristics of the annual temperature changes are clearly different between northern and southern China, and our period superimposition extrapolation shows that both annual and winter temperatures in China will continue to increase in the next 20 years, more so in northern China and in the Qinghai-Xizang Plateau (QXP) than in the southern region, except in the southwest. If temperatures follow historic increasing linear trends, the overall temper- ature is expected to increase by 1℃ between 2010 and 2029. 展开更多
关键词 climate regions in China temperature change period wavelet analysis temperature prediction
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Characteristics of Temperature Change in China over the Last 2000 years and Spatial Patterns of Dryness/Wetness during Cold and Warm Periods 被引量:10
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作者 Quansheng GE Haolong LIU +2 位作者 Xiang MA Jingyun ZHENG Zhixin HAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第8期941-951,共11页
This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation ... This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃(100 yr)^(-1); however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern: dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China. 展开更多
关键词 temperature change dry-wet spatial pattern cold and warm periods last 2000 years China
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Spatial / Temporal Features of Antarctic Climate Change
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作者 葛玲 梁佳兴 陈毅良 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1996年第3期375-382,共8页
Bused on January 1962-October 1993 mean value series of monthly mean temperature anomalies of 16 Antarctic stations on 10 standard isobanc surfaces from the surface to the 30 hPa,long term trends and periodic features... Bused on January 1962-October 1993 mean value series of monthly mean temperature anomalies of 16 Antarctic stations on 10 standard isobanc surfaces from the surface to the 30 hPa,long term trends and periodic features of climate changes from the troposphere to the lower stratosphere over the Antarctic region are investigated by maximum entropy power spectrum analysis,and the relation between climate change of the stratosphere (troposphere) and tolal ozone (southern 500 hPa circulation) is discussed. 展开更多
关键词 ANTARCTIC Climate change: Long term trend Periodicity Total ozone
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Changes of the Period and the Light Curves of the Contact Binary V1073 Cygni
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作者 Yang Yulan, Liu Qingyao (Yunnan Observatory, The Chinese Academy of Sciences, Kunming 650011, China) (United Laboratory of Optical Astronomy, The Chinese Academy of Sciences, Kunming 650011, China) (National Astronomical Observatories, The Chinses Acad 《天文研究与技术》 CSCD 1999年第S1期373-377,共5页
Observational evidence of unstable behavior for the W UMa type binary system V1073 Cygni is presented in this paper. Around 1939 the period of the binary suddenly decreased by 0 580 seconds and again suddenly decrease... Observational evidence of unstable behavior for the W UMa type binary system V1073 Cygni is presented in this paper. Around 1939 the period of the binary suddenly decreased by 0 580 seconds and again suddenly decreased by 0 746 seconds around 1981.Obvious variable O’ Connell effect of the light curves in V can be seen. The relation between the changes in the orbital period and variation in the O’ Connell effect and possible reasons for the unstable behavior of V1073 Cyg were discussed. 展开更多
关键词 changes of the Period and the Light Curves of the Contact Binary V1073 Cygni
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Study on microbial protein and the mechanism of solid-state fermentation with periodical dynamic changes of air
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作者 FU Xiaoguo CHEN Hongzhang +1 位作者 LI Hongqiang MA Runyu 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2007年第2期113-117,共5页
The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation(SSF)and the effect of periodical dynamic changes of air on protein have been studied.The m... The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation(SSF)and the effect of periodical dynamic changes of air on protein have been studied.The mechanism of solid-state fermentation with periodical dynamic changes of air is also discussed.Compared with static solid-state fermentation,periodical dynamic changes of air afford a higher protein mass;from 1 g of the fermentation microbe,5.3 mg of the intracellular protein(an increase of 34.63%)and 9.09 mg of the extracellular protein(an increase of 17.8%)were obtained on the sixth day of fermentation.The filter paper activity and carboxymethyl cellulose activity(FPA and CMCase)of the extracellular protein are 1.739μmol/s and 109.592μmol/s,respectively,which represent increases of 60.1%and 21.2%over the corresponding values for static solid-state fermentation.The FPA and CMCase of the intra-cellular protein are 0.245μmol/s and 6.392μmol/s,respec-tively,which represent decreases of 22.2%and 38.7%over the corresponding values for static solid-state fermentation.The enzyme activity of the microbial extracellular protein in solid-state fermentation with periodical dynamic changes of air on the fifth day is nearly equal to that on the sixth day without periodical dynamic changes of air,so the period of fermentation can be shortened.The sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)experiments suggest that pulsating air pressure stimulation leads to a decrease in the amount of protein component with molecule mass of about 80400Da,and an increase in the amount of protein component with molecule mass of about 28520Da. 展开更多
关键词 periodical dynamic changes of air periodic stimulation microbe of solid-state fermentation PROTEIN
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On the Period Variation of the W UMa-type Contact Binary V502 Ophiuchi
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作者 Qing-Yao Liu Yu-Lan Yang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2006年第3期331-337,共7页
The variation in the orbital period of the W UMa type contact binary V502 Oph is analyzed. The orbital period exhibits a wavelike variation with a periodicity of 23.0 years and an amplitude of AP = 1.24 ×10^-5 da... The variation in the orbital period of the W UMa type contact binary V502 Oph is analyzed. The orbital period exhibits a wavelike variation with a periodicity of 23.0 years and an amplitude of AP = 1.24 ×10^-5 days superimposed on secular decrease of dP/dt = 1.68× 10^-7 day per year. The long-term decrease may be accompanied by the contraction of the secondary at a rate of 83 m per year and a mass transfer rate from the primary to the secondary of 4.28×10^-8M· per year. The short-term oscillation may be explained by the presence of a third component. Orbital elements of the third body and its possible mass are presented. 展开更多
关键词 stars: contact binary - period change - star: individual: V502 Oph
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Restoration of eroded stratal thickness in key periods of tectonic change in a multi-stage superimposed Tarim Basin in China 被引量:1
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作者 Liu Hao1, Wang Yingmin2 1. School of Marine Sciences, China University of Geosciences (Beijing), Beijing 100083, China 2. School of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China 《Journal of Palaeogeography》 SCIE 2012年第2期149-171,共23页
With an area of 56×104km2, the Tarim Basin is the largest inland basin in China and is also generally acknowledged as one of the most important areas for potential oil and gas exploration. On the basis of data fr... With an area of 56×104km2, the Tarim Basin is the largest inland basin in China and is also generally acknowledged as one of the most important areas for potential oil and gas exploration. On the basis of data from 22 regional seismic profiles and 40 drilling wells, 15 important first-order and second-order regional unconformities were defined.Almost all the main unconformities are superimposed unconfomities. Since the Cambrian, 5 key periods of tectonic change have occurred during the evolution of the Tarim Basin. The total eroded stratal thickness of the above-mentioned unconformities was calculated by using the method of virtual extrapolation of seismic reflection. The results indicate that the total eroded stratal thickness of different periods is quite different in different locations of the basin. Taking the Upper-Middle Ordovician as an example, its thickness restoration of eroded strata was calculated into individual stages i.e. its thickness restoration of eroded strata was calculated to different tectonic periods. Otherwise, as for the specific period of tectonic change, the underlying strata were, respectively eroded and thus the thickness restoration of eroded strata was calculated into individual intervals. Taking the Early Hercynian period as an example, the eroded stratal thickness was calculated into individual intervals to calculate the ratio of intervals of various ages occupying the total eroded thickness. The results show that for the same stratum, its degree of erosion is quite different in different periods and at different locations, due to the varying influence of tectonic movement. The unconformities of some key periods of tectonic change have different controls on the degree of erosion and the eroded range of the individual period of the underlying strata which are the typical characteristics of multi-stage superimposition of unconformities in the Tarim Basin. 展开更多
关键词 Tarim Basin extrapolation of virtual surface key period of tectonic change superimposed unconformity restoration of eroded stratal thickness
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Changes of the Important Period of Strategic Opportunities and Our Response
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作者 Zhang Boli 《Peace》 2013年第1期7-11,共5页
Currently,the fundamental judgment that China remains in an important period of strategic opportunities for its development has not changed,however new changes have taken place in the nature and the conditions of this... Currently,the fundamental judgment that China remains in an important period of strategic opportunities for its development has not changed,however new changes have taken place in the nature and the conditions of this period.On a higher starting point of development,China is faced with unprecedented opportunities for development as well as challenges unknown before. 展开更多
关键词 CPC MORE changes of the Important Period of Strategic Opportunities and Our Response OUTLOOK
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