期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
古生界海陆过渡相黑色泥质岩系显微组分特征及生气潜力评价
1
作者 赵林 贾蓉芬 +2 位作者 刘德汉 秦建中 张文龙 《沉积学报》 CAS CSCD 北大核心 1995年第2期105-111,共7页
本文对华北和下扬子区两种类型的海陆过渡相地层进行详细的有机岩学工作,研究了泥质岩系中有机显微组合的岩石学特征、有机显微组成特征,表明壳质组是重要的生气母质。根据气源岩中有机显微组分组成特征,结合模拟实验结果提出产气指... 本文对华北和下扬子区两种类型的海陆过渡相地层进行详细的有机岩学工作,研究了泥质岩系中有机显微组合的岩石学特征、有机显微组成特征,表明壳质组是重要的生气母质。根据气源岩中有机显微组分组成特征,结合模拟实验结果提出产气指数的计算方法,并根据产气指数判断气源岩的生气潜力,下扬子区泥岩为好的生气源岩,华北地区的泥岩为较好的生气源岩,它们比煤具更大的生气能力。 展开更多
关键词 泥质岩 海陆地渡相 显微组分 生气指数 天然气
下载PDF
Relationship between Rice Planthopper Occurrence Area in China and Atmospheric Circulation Indices 被引量:3
2
作者 季璐 朱敏 《Agricultural Science & Technology》 CAS 2012年第9期2006-2011,共6页
[Objective] This study aimed to establish models based on atmospheric cir- culation indices for forecasting the area attacked by rice planthopper every year, and to provide guide for preventing and controlling plantho... [Objective] This study aimed to establish models based on atmospheric cir- culation indices for forecasting the area attacked by rice planthopper every year, and to provide guide for preventing and controlling planthopper damage. [Method] The data related to rice planthopper occurrence and atmospheric circulation were collected and analyzed with the method of stepwise regression to establish the prediction models. [Result] The factors significantly related to the area attacked by rice plan-thopper were selected. Two types of prediction models were established. One was for Sogatella furcifera (Horvath), based on Atlantic-Europe circulation pattern W in October in that year, Pacific polar vortex area index in October in that year, North America subtropical high index in August in that year, Atlantic-Europe circulation pattern W in June in that year, northern boundary of North America subtropical high in February in that year, Atlantic-Europe polar vortex intensity index in October in that year and Asia polar vortex intensity index in November in the last year; the other type of prediction models were for Nilaparvata lugens (Stal), based on the Eastern Pacific subtropical high intensity index in July in that year, northern hemi- sphere polar vortex area index in October in the last year, Asia polar vortex strength index in November in the last year, north boundary of North America-At- lantic subtropical high in September in that year, north boundary of North Africa-At- lantic-North America subtropical high in January in that year, sunspot in September of the last year and eastern Pacific subtropical high area index in September in that year. [Conclusion] With the stepwise regression, the forecasting equations of the rice planthopper occurrence established based on the atmospheric circulation indices could be used for actual forecast. 展开更多
关键词 Rice planthopper Atmospheric circulation Prediction models
下载PDF
Driving force and changing trends of vegetation phenology in the Loess Plateau of China from 2000 to 2010 被引量:10
3
作者 WANG Hao LIU Guo-hua +3 位作者 LI Zong-shan YE Xin WANG Meng GONG Li 《Journal of Mountain Science》 SCIE CSCD 2016年第5期844-856,共13页
Changes in vegetation phenology are key indicators of the response of ecosystems to climate change.Therefore,knowledge of growing seasons is essential to predict ecosystem changes,especially for regions with a fragile... Changes in vegetation phenology are key indicators of the response of ecosystems to climate change.Therefore,knowledge of growing seasons is essential to predict ecosystem changes,especially for regions with a fragile ecosystem such as the Loess Plateau.In this study,based on the normalized difference vegetation index(NDVI) data,we estimated and analyzed the vegetation phenology in the Loess Plateau from 2000 to 2010 for the beginning,length,and end of the growing season,measuring changes in trends and their relationship to climatic factors.The results show that for 54.84% of the vegetation,the trend was an advancement of the beginning of the growing season(BGS),while for 67.64% the trend was a delay in the end of the growing season(EGS).The length of the growing season(LGS) was extended for 66.28% of the vegetation in the plateau.While the temperature is important for the vegetation to begin the growing season in this region,warmer climate may lead to drought and can become a limiting factor for vegetation growth.We found that increasedprecipitation benefits the advancement of the BGS in this area.Areas with a delayed EGS indicated that the appropriate temperature and rainfall in autumn or winter enhanced photosynthesis and extended the growth process.A positive correlation with precipitation was found for 76.53% of the areas with an extended LGS,indicating that precipitation is one of the key factors in changes in the vegetation phenology in this water-limited region.Precipitation plays an important role in determining the phenological activities of the vegetation in arid and semiarid areas,such as the Loess Plateau.The extended growing season will significantly influence both the vegetation productivity and the carbon fixation capacity in this region. 展开更多
关键词 The Loess Plateau Trend analysis PHENOLOGY NDVI Vegetation green-up date
下载PDF
Clipping Alters the Response of Biomass Production to Experimental Warming: A Case Study in an Alpine Meadow on the Tibetan Plateau, China 被引量:8
4
作者 FU Gang SUN Wei +5 位作者 YU Cheng-Qun ZHANG Xian-Zhou SHEN Zhen-Xi LI Yun-Long YANG Peng-Wan ZHOU Nan 《Journal of Mountain Science》 SCIE CSCD 2015年第4期935-942,共8页
Predicting how human activity will influence the response of alpine grasslands to future warming has many uncertainties.In this study, a field experiment with controlled warming and clipping was conducted in an alpine... Predicting how human activity will influence the response of alpine grasslands to future warming has many uncertainties.In this study, a field experiment with controlled warming and clipping was conducted in an alpine meadow at three elevations(4313 m, 4513 m and 4693 m) in Northern Tibet to test the hypothesis that clipping would alter warming effect on biomass production.Open top chambers(OTCs) were used to increase temperature since July,2008 and the OTCs increased air temperature by approximately 0.9o C ~ 1.8o C during the growing in2012.Clipping was conducted three times one year during growing season and the aboveground parts of all live plants were clipped to approximately 0.01 m in height using scissors since 2009.Gross primary production(GPP) was calculated from the Moderate-Resolution Imaging Spectroradiometer GPP algorithm and aboveground plant production was estimated using the surface-measured normalized difference vegetation index in 2012.Warming decreased the GPP, aboveground biomass(AGB) and aboveground net primary production(ANPP) at all three elevations when clipping was not applied.In contrast, warming increased AGB at all three elevations, GPP at the two lower elevations and ANPP at the two higher elevations when clipping was applied.These findings show that clipping reduced the negative effect of warming on GPP, AGB and ANPP, suggesting that clipping may reduce the effect of climate warming on GPP, AGB and ANPP in alpine meadows on the Tibetan Plateau, and therefore, may be a viable strategy for mitigating the effects of climate change on grazing and animal husbandry on the Tibetan Plateau. 展开更多
关键词 CLIPPING Gross primary production Open top chamber WARMING Alpine Meadow Tibetan Plateau
下载PDF
Effect of climate change on seasonal water use efficiency in subalpine Abies fabri 被引量:4
5
作者 SUN Xiang-yang WANG Gen-xu +2 位作者 HUANG Mei HU Zhao-yong SONG Chun-lin 《Journal of Mountain Science》 SCIE CSCD 2017年第1期142-157,共16页
Abies fabri is a typical subalpine dark coniferous forest in southwestern China. Air temperature increases more at high elevation areas than that at low elevation areas in mountainous regions,and climate change ratio ... Abies fabri is a typical subalpine dark coniferous forest in southwestern China. Air temperature increases more at high elevation areas than that at low elevation areas in mountainous regions,and climate change ratio is also uneven in different seasons. Carbon gain and the response of water use efficiency(WUE) to annual and seasonal increases in temperature with or without CO_2 fertilization were simulated in Abies fabri using the atmospheric-vegetation interaction model(AVIM2). Four future climate scenarios(RCP2.6,RCP4.5,RCP6.0 and RCP8.5) from the Coupled Model Intercomparison Project Phase 5(CMIP5) were selectively investigated. The results showed that warmer temperatures have negative effects on gross primary production(GPP) and net primary production(NPP) in growing seasons and positive effects in dormant seasons due to the variation in the leaf area index. Warmer temperatures tend to generate lower canopy WUE and higher ecosystem WUE in Abies fabri. However,warmer temperature together with rising CO_2 concentrations significantlyincrease the GPP and NPP in both growing and dormant seasons and enhance WUE in annual and dormant seasons because of the higher leaf area index(LAI) and soil temperature. The comparison of the simulated results with and without CO_2 fertilization shows that CO_2 has the potential to partially alleviate the adverse effects of climate warming on carbon gain and WUE in subalpine coniferous forests. 展开更多
关键词 Climate change Carbon gain Water use efficiency Atmospheric-vegetation interaction model
下载PDF
社会语言学视角下医患门诊会话中打断现象的研究 被引量:1
6
作者 陈倩茹 黄姗 +1 位作者 张启宝 万飞 《进展》 2022年第7期224-228,共5页
目的:探究门诊会话中医生打断患者的原因与阻碍医患关系和谐发展的打断因素。方法:明确医患打断定义的基础上,定性探究打断的分类以及医生打断患者的原因,同时定量研究造成患者不良情绪产生的因素。结果:门诊医患会话中,医生占据绝对权... 目的:探究门诊会话中医生打断患者的原因与阻碍医患关系和谐发展的打断因素。方法:明确医患打断定义的基础上,定性探究打断的分类以及医生打断患者的原因,同时定量研究造成患者不良情绪产生的因素。结果:门诊医患会话中,医生占据绝对权势;合作性打断以及反对型干扰性打断对患者情绪影响不大;忽视型与话题转换型的干扰性打断易导致患者情绪不良。结论:医生合理利用合作性打断以及反对型干扰性打断有利于提高诊疗效率;但应避免使用忽视型与话题转换型的干扰性打断以避免患者情绪不良。 展开更多
关键词 门诊会话 合作性打断 干扰性打断 生气指数 医患关系
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部