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temperature variation and abrupt change analysis in the Three-River Headwaters Region during 1961-2010

Journal of Geographical Sciences 2012年第3期22卷 451-469页

作者： Yi Xiangsheng Li Guosheng Yin Yanyu Chinese Acad Sci Inst Geog Sci & Nat Resources Res Beijing 100101 Peoples R China Chinese Acad Sci Grad Univ Beijing 100049 Peoples R China Beijing Normal Univ Sch Geog Beijing 100875 Peoples R China Beijing Normal Univ Key Lab Reg Geog Beijing 100875 Peoples R China

In this study, a monthly dataset of temperature time series （1961-2010） from 12 meteorological stations across the Three-River Headwater Region of Qinghai Province （THRHR） was used to analyze the climate change. The temperature variation and abrupt change analysis were examined by using moving average, linear regression, Spline interpolation, Mann-Kendall test and so on. Some important conclusions were obtained from this research, which mainly contained four aspects as follows. （1） There were several cold and warm fluctuations for the annual and seasonal average temperature in the THRHR and its three sub-headwater regions, but the temperature in these regions all had an obviously rising trend at the statistical significance level, especially after 2001. The spring, summer, autumn and annual average temperature increased evidently after the 1990s, and the winter average temperature exhibited an obvious upward trend after entering the 21st century. Except the standard value of spring temperature, the annual and seasonal temperature standard value in the THRHR and its three sub-headwater regions increased gradually, and the upward trend for the standard value of winter average temperature indicated significantly. （2） The tendency rate of annual average temperature in the THRHR was 0.36℃ 10a^-1, while the tendency rates in the Yellow River Headwater Region （YERHR）, Lancangjiang River Headwater Region （LARHR） and Yangtze River Headwater Region （YARHR） were 0.37℃ 10a^-1, 0.37℃ 10a^-1 and 0.34℃10a^-1 respectively. The temperature increased significantly in the south of Yushu County and the north of Nangqian County. The rising trends of temperature in winter and autumn were higher than the upward trends in spring and summer. （3） The abrupt changes of annual, summer, autumn and winter average temperature were found in the THRHR, LARHR and YARHR, and were detected for the summer and autumn average temperature in the YERHR. The abrupt changes of annual and summer average tempe

关键词： temperature variation inter-annual change inter-decadal change standard value change abruptchange analysis Three.River Headwaters Region

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temperature variation of concrete box girder bridge

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Frontiers of Structural and Civil Engineering 2009年第4期3卷 407-413页

作者： Jian WANG Zhi FANG Wuhan Municipal Engineering Design Institute Wuhan 430015China College of Civil Engineering Hunan UniversityChangsha 410082China

On the basis of theoretical analysis and measurement on site,the temperature gradients and its variation on concrete box girder bridges resulting from ambient temperature,solar radiation,and structural temperature fields were *** the help of the heat transfer theory and finite element method(FEM),the heat flux of the surface of concrete box girder was carried out,and all the heat fluxes were described as the *** results were compared with that from field measurements,and a good correlation was *** was revealed that the methods,the parameters,the boundary condition used in this paper were ***,some conclusions were obtained,which could provide the basis for box girder design under solar radiation.

关键词： concrete box girder solar radiation convection finite element method(FEM) temperature variation

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Holocene temperature variation recorded by branched glycerol dialkyl glycerol tetraethers in a loess-paleosol sequence from the north-eastern Tibetan Plateau

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Frontiers of Earth Science 2023年第4期17卷 1012-1025页

作者： Tianxiao WANG Duo WU Tao WANG Lin CHEN Shilong GUO Youmo LI Chenbin ZHANG Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China Alpine Paleoecology and Human Adaptation Group(ALPHA) Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Reconstructing Holocene temperature evolution is important for understanding present temperature variations and for predicting future climate change,in the context of global *** evolution of Holocene global temperature remains disputed,due to differences between proxy reconstructions and model simulations,a discrepancy known as the῾Holocene temperature conundrum᾽.More reliable and quantitative terrestrial temperature records are needed to resolve the spatial heterogeneity of existing *** this study,based on the analysis of branched glycerol dialkyl glycerol tetraethers(brGDGTs)from a loess-paleosol sequence from the Ganjia Basin in the north-eastern Tibetan Plateau(NETP),we quantitatively reconstructed the mean annual air temperature(MAAT)over the past 12 *** MAAT reconstruction shows that the temperature remained low during the early Holocene(12−8 ka),followed by a rapid warming at around 8 *** 8 to 4 ka,the MAAT record reached its highest level,followed by a cooling trend from the late Holocene(4−0 ka).The variability of the reconstructed MAAT is consistent with trends of annual temperature records from the Tibetan Plateau(TP)during the *** attribute the relatively low temperatures during the early Holocene to the existence of ice sheets at high-latitude regions in the Northern Hemisphere and the weaker annual mean insolation at 35°*** the mid to late Holocene,the long-term cooling trend in the annual temperature record was primarily driven by declining summer *** study provides key geological evidence for clarifying Holocene temperature change in the TP.

关键词： sHolocene Ganjia Basin loess temperature variation BrGDGTs

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Thermoelectromechanical instability of dielectric elastomer undergoes polarization saturation and temperature variation

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Acta Mechanica Sinica 2021年第3期37卷 414-421,I0001页

作者： Yaguang Guo Liwu Liu Yanju Liu Jinsong Leng Department of Astronautical Science and Mechanics Harbin Institute of TechnologyHarbin 150001.China Center for Composite Materials and Structures Science Park of Harbin Institute of TechnologyHarbin 150080China

When the electric field caused by voltage reaches a certain level,the charge on the compliant electrodes will not increase owing to the polarization saturation,which would limit the deformation of the dielectric *** experiments show that temperature also has a significant effect on the deformation of dielectric *** this work,a free energy model coupling temperature and polarization saturation is developed to characterize the thermoelectromechanical instability of dielectric *** results reveal that both the polarization saturation parameters and electric field have a significant influence on the actuation ability of the dielectric elastomer,and the increase of temperature enhances thermoelectromechanical *** is hoped that this work could guide the development of dielectric elastomer materials and application devices operating in variable temperatures.

关键词： Dielectric elastomer Thermoelectromechanical instability Polarization saturation temperature variation

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Improvement of machining quality of copper-plated roll mold by controlling temperature variation

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 37-41页

作者： Tae-Jin JE Eun-Chae JEON Sang-Cheon PARK Doo-Sun CHOI Kyung-Hyun WHANG Myung-Chang KANG Division of Nano-Mechanical Systems Korea Institute of Machinery and Materials Daejeon 305-343 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

Micro prism film used in LCD industry can be manufactured by roll to roll method with copper-plated roll mold. As copper-plated roll mold is getting larger, pitch error is getting severer. The pitch error drops the quality of micro prism film. The main cause of the pitch error was investigated during machining large roll mold whose machined length was 1 200 mm. The temperature of machining system was elevated during machining roll mold, and this elevation induced thermal expansion of the system. The temperature variation around the roll mold also made thermal expansion of the roll mold. The amount of thermal expansion had strong relationship to the amount of pitch error. Therefore, the roll mold was machined after warming-up of machining system and precise temperature controller around copper-plated roll mold was installed, which minimized the temperature variation. Finally, precise micro prism patterns without pitch error were machined on the large roll mold.

关键词： copper-plated roll mold machining prism pattern temperature variation

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temperature variation in Guangdong Province, China

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Journal of Geographical Sciences 1999年第2期9卷 95-104页

作者： YAN Yuk Yee (Department of Geography,Hong Kong Baptist University Kowloon Tong. Hong Kong)

temperature variation in Guangdong Province of China between 1956 and 1990 was investigaed Simple linear trend analysis was ed to examine the temporal trend and the climatic departure index (CDI) was employed to study the regional variability Warming trends in maximum,minimum and average temperatures discovered for both winter and summer For annual temperatures a cooling trend in maximum temperature was observed. The mostrecent decade was found to be warmer than the previous ones. A detailed esamination of Shenzhen revealed that warming trebds were more prominent than regional average trend,indicating that urbanization and industrialization might influence the average temperature trends. The results of the CDI analysis showed that temperatures had not become mere variable.

关键词： temperature variation climatic indexl index Guangdong

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Short-term effect of temperature variation on the competition between PAOs and GAOs during acclimation period of an EBPR system

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Frontiers of Environmental Science & Engineering 2011年第2期5卷 277-282页

作者： Nanqi REN Han KANG Xiuheng WANG Nan LI State Key Laboratory of Urban Water Resource and Environment Harbin Institute of TechnologyHarbin 150090China

Sequencing batch reactor(SBR)for enhanced biological phosphorus removal(EBPR)processes was used to investigate the impact of the temperature shock on the competition between phosphorus-accumulating organisms(PAOs)and glycogen accumulating organisms(GAOs)in start-up *** the 34 days operation,SBR was set with temperature variation(0-5 d,22±1℃;6-13 d,29±1℃;14-34 d,14±1℃).PAOs and GAOs were analyzed by fluorescent in situ hybridization(FISH),and intracellular polyphosphate granules were stained by *** results showed that the influence of temperature shock on PAOs’abundance was more serious than that on GAOs in the enriching *** sudden and substantially temperature variation,from 22±1℃ to 29±1℃ and then to 14±1℃,the domination of PAOs was *** temperature shock,PAOs’competitive advantages at low temperature that concluded in other study did not appear in our *** mesophilic,GAOs(indicated by Alphaproteobacteria and Gammaproteobacteria)were more temperature adaptive and better grew and took the domination at 14±1℃ in the *** the competition process,organisms of tetrad forming organisms(TFOs)-like shape which were considered as typical GAOs,were *** the evidence of poly-P granules containing by Neisser-straining and result of FISH,these organisms of TFOs-like shape were better to be assumed as adaption state or a special self-protecting shape of PAOs.

关键词： fluorescent in situ hybridization(FISH) tetrad forming organisms(TFOs) temperature variation enhanced biological phosphorus removal(EBPR)

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temperature variation and Mutation Analysis over the Past 59 Years in Shenyang

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Meteorological and Environmental Research 2010年第11期1卷 33-35,39页

作者：王明华孙晓巍李广霞戴廷仁沈阳中心气象台辽宁沈阳110016

In this paper,based on the observation data of air temperature during 1951-2009 in Shenyang,the interannual and interdecadal variation of annual average temperature,maximum and minimum temperature in Shenyang were conducted the statistical analysis by means of linear trend estimation and mutation detection by using Mann-Kendall *** was demonstrated in the results,the annual average temperature,maximum and minimum temperature in Shenyang showed an upward trend,whose linear tendency rate was 0.231,0.181 and 0.218 *** increment trend of annual average temperature,maximum and minimum temperature was extremely *** increase in minimum temperature was more significant than that in mean temperature and maximum *** abrupt change point of annual mean temperature in Shenyang appeared in 1981;the abrupt change point of annual mean maximum temperature appeared in 1994;the annual mean minimum temperature underwent mutation in 1978.

关键词： Shenyang temperature variation Mutation analysis Mann-Kendall statistical test China

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Analysis of sensitivity to hydrate blockage risk in natural gas gathering pipeline

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Petroleum Science 2024年第4期21卷 2723-2733页

作者： Ao-Yang Zhang Meng Cai Na Wei Hai-Tao Li Chao Zhang Jun Pei Xin-Wei Wang State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Research Institute of Production Engineering Daqing Oilfield Co.Ltd.

During the operational process of natural gas gathering and transmission pipelines, the formation of hydrates is highly probable, leading to uncontrolled movement and aggregation of hydrates. The continuous migration and accumulation of hydrates further contribute to the obstruction of natural gas pipelines, resulting in production reduction, shutdowns, and pressure build-ups. Consequently, a cascade of risks is prone to occur. To address this issue, this study focuses on the operational process of natural gas gathering and transmission pipelines, where a comprehensive framework is established. This framework includes theoretical models for pipeline temperature distribution, pipeline pressure distribution, multiphase flow within the pipeline, hydrate blockage, and numerical solution methods. By analyzing the influence of inlet temperature, inlet pressure, and terminal pressure on hydrate formation within the pipeline, the sensitivity patterns of hydrate blockage risks are derived. The research indicates that reducing inlet pressure and terminal pressure could lead to a decreased maximum hydrate formation rate, potentially mitigating pipeline blockage during natural gas transportation. Furthermore, an increase in inlet temperature and terminal pressure, and a decrease in inlet pressure, results in a displacement of the most probable location for hydrate blockage towards the terminal station. However,it is crucial to note that operating under low-pressure conditions significantly elevates energy consumption within the gathering system, contradicting the operational goal of energy efficiency and reduction of energy consumption. Consequently, for high-pressure gathering pipelines, measures such as raising the inlet temperature or employing inhibitors, electrical heat tracing, and thermal insulation should be adopted to prevent hydrate formation during natural gas transportation. Moreover, considering abnormal conditions such as gas well production and pipeline network s

关键词： Natural gas hydrates Gathering pipeline temperature variation Hydrate formation rate Sensitivity analysis

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Effect of variation of the Coefficient of Friction on the temperature at the Level of the Fault Lips

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Open Journal of Earthquake Research 2022年第3期11卷 45-72页

作者： Francis Olivier Djiogang Fidèle Koumetio David Yemele Guy Pascal Konga Guillaume L. Ymeli Unit of Research of Mechanics and Modelling of Physical Systems Department of Physics Faculty of Science University of Dschang Dschang Cameroon

Earth’s crust is an anisotropic and purely heterogeneous medium, which is justified by existence of different discontinuities;our study aims to show the effect of the variation of coefficient of friction on the evolution of temperature and its impact on seismic forecasting. In this work, we are model in 2D the variation of thermal energy and temperature produced by friction at the level of fault lip as function of depth of the seismic focus and at different value of time. Earthquakes are born when the energy accumulated by friction at the level of fault is suddenly released causing damage, sometimes noticeable on the surface of earth (macroseisms), and sometimes not at all noticeable on the surface of earth (microseisms), then energy which occurs before is important to forecasting earthquake. Assuming that coefficient of friction is variable, our results have enabled us to highlight the fact that, the greater the coefficient of friction, more the temperature increases, although the temperature profile increase over time but not linearly reflecting the presence of different asperities and discontinuities zone;slip generated at the level of fault occur a variation of temperature on specific points called roughness in common agreement with the literature. A large part of energy produced by friction is dissipated in heat causing a local increases in temperature which a very short duration and called flash contact temperature, and that despite the fact that the temperature evolved in time and space, it all converged towards a perfectly distinguishable fixed point.

关键词： Earthquakes Coefficient of Friction Nucleation Phase temperature variation Energy variation Asperity Point

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