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韶关地区强降水概率分布特征及环流背景分析研究
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作者 黄少忠 汤蓬辉 +1 位作者 赵亮巨 江清华 《气象水文海洋仪器》 2024年第5期75-78,共4页
文章利用勒帕热检验法和广义极值分布对韶关地区的强降水概率分布特征进行了分析,并对其环流背景进行了研究。研究结果表明:韶关地区的强降水趋势在1992年发生由减小到增加的突然变化,前汛期的强降水量和强降水强度降低,后汛期明显增加... 文章利用勒帕热检验法和广义极值分布对韶关地区的强降水概率分布特征进行了分析,并对其环流背景进行了研究。研究结果表明:韶关地区的强降水趋势在1992年发生由减小到增加的突然变化,前汛期的强降水量和强降水强度降低,后汛期明显增加;韶关地区从南到北的平均日最大降水量、暴雨天数等空间分布,前汛期呈现“南多北少”、后汛期呈现“东多中少”的特征;强降水的环流背景主要是澳大利亚高压和马斯克林高压的强度变化,两高压同时增强时,韶关地区前汛期强降水偏少,后汛期强降水偏多。希望研究结果能为韶关地区的强降水预报和防灾减灾工作提供参考价值。 展开更多
关键词 勒帕热检验法 广义极值分布 强降水 概率分布特征 环流背景
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考虑淋巴微循环的体循环分析
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作者 李明阳 赵良举 +1 位作者 蔡肖 徐克 《重庆大学学报(自然科学版)》 EI CAS CSCD 北大核心 2019年第3期50-57,共8页
基于流体网络动力学和电路图论原理建立了带有淋巴系统的人体血液循环流体网络模型,用10次谐波来模拟流量表达式。改变模型分支流阻,从血流动力学层面来模拟淋巴分支对血液循环的影响以及各分支之间的相互影响。用平均法求解模型中的血... 基于流体网络动力学和电路图论原理建立了带有淋巴系统的人体血液循环流体网络模型,用10次谐波来模拟流量表达式。改变模型分支流阻,从血流动力学层面来模拟淋巴分支对血液循环的影响以及各分支之间的相互影响。用平均法求解模型中的血流动力学宏观参数,并从生物物理角度讨论了淋巴分支对微循环的影响。结果表明:淋巴循环障碍,淋巴分支流阻比η=3时,该分支平均流量相对于正常值减小42.24%,对其他分支流量影响不超过0.04%;各分支的流阻变化会对淋巴分支的流量产生至少2.69%的影响。 展开更多
关键词 淋巴系统 血流动力学 微循环 流体网络模型 流量影响
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秦岭山区商洛市大气降水化学组成特征及来源分析 被引量:10
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作者 李晓刚 赵良菊 +4 位作者 刘琼 赵咏琪 成静 卢久菊 赵培琦 《水资源与水工程学报》 CSCD 2020年第4期24-30,共7页
为了解秦岭山区城市大气降水化学组成与来源,2018年1-12月共收集商洛市有效降水样品40个,分析了p H、电导率(EC)和主要离子浓度(F-、Cl-、NO3-、SO42-、NH4+、K+、Na+、Ca2+和Mg2+)。结果表明:商洛市降水p H和电导率的加权平均值分别为6... 为了解秦岭山区城市大气降水化学组成与来源,2018年1-12月共收集商洛市有效降水样品40个,分析了p H、电导率(EC)和主要离子浓度(F-、Cl-、NO3-、SO42-、NH4+、K+、Na+、Ca2+和Mg2+)。结果表明:商洛市降水p H和电导率的加权平均值分别为6.76和34.35μS/cm,降水总离子浓度加权平均值为452.89μeq/L;主要阴离子为SO42-和NO3-,分别占总阴离子浓度的59.20%和31.93%,主要阳离子为NH4+和Ca2+,分别占阳离子浓度的39.21%和33.87%,中和因子(NF)也表明二者中和能力最强;总离子浓度冬季高,夏秋季低,呈现明显的季节变化特征;相关分析表明NH4+、Ca2+与SO42-、NO3-之间相关系数均大于0.7,说明商洛大气中存在着NH4NO3、Ca(NO3)2、(NH4)2SO4、CaSO4和NH4HSO4等物质;富集因子计算表明,SO42-和NO3-主要来自人为活动,Ca2+、Mg2+和K+主要来自陆源的岩石土壤风化,Cl-主要来自于海洋源。 展开更多
关键词 城市降水 化学组成 离子来源 秦岭山区 商洛市
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黑河上游青海云杉森林生态系统蒸散发分割 被引量:5
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作者 彭文丽 赵良菊 +4 位作者 谢聪 董玺莹 刘全玉 李瑞峰 潘昭烨 《冰川冻土》 CSCD 北大核心 2020年第2期629-640,共12页
通过对黑河上游排露沟流域海拔2 700m和2 900m处青海云杉森林生态系统不同季节的土壤水、植物水和大气水汽等不同水体稳定氧同位素组成(δ18O)的测定,运用Craig-Gordon模型、同位素稳态假设和Keeling Plot模型分别得出土壤蒸发、植物蒸... 通过对黑河上游排露沟流域海拔2 700m和2 900m处青海云杉森林生态系统不同季节的土壤水、植物水和大气水汽等不同水体稳定氧同位素组成(δ18O)的测定,运用Craig-Gordon模型、同位素稳态假设和Keeling Plot模型分别得出土壤蒸发、植物蒸腾和蒸散发的δ18O,结合多元线性混合模型将生态系统蒸散发分割为土壤蒸发和植物蒸腾。结果表明:土壤蒸发水汽的δ18OE、植物蒸腾水汽的δ18OT及蒸散发水汽的δ18OET分别介于-35.9‰^-25.2‰、-9.0‰^-4.2‰和-18.5‰^-10.2‰之间,三者顺序为δ18OT>δ18OET>δ18OE,满足同位素稳态假设。植物蒸腾对蒸散发的贡献率(fT)在52.2%~88.4%之间变化,土壤蒸发对蒸散发的贡献率(fE)在11.6%~47.8%之间变化,fT远大于fE,说明生态系统蒸散发大部分来自于植物蒸腾,即植物蒸腾是青海云杉森林生态系统蒸散发的重要组成部分。fT与气温呈负相关,而与相对湿度呈正相关,说明气温对fT起抑制作用,相对湿度对fT起促进作用,但是相关系数不高,说明fT在自然环境下还可能受除气温和相对湿度外的多种环境因素和生物因素综合影响,具体影响机理有待进一步探究。本研究结果可为进一步研究黑河流域区域内循环和流域尺度水循环研究提供理论依据。 展开更多
关键词 黑河上游 蒸散发分割 土壤蒸发 植物蒸腾
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基于传输线模型的人体脉搏波仿真分析 被引量:2
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作者 蔡肖 赵良举 +1 位作者 周正刚 江宇桓 《重庆大学学报(自然科学版)》 EI CAS CSCD 北大核心 2019年第7期27-35,共9页
利用55段人体动脉树建立传输线模型,数值仿真人体动脉树中脉搏波的传播,在心脏输出体积流率波一定的条件下,改变模型分支外周阻力来探讨阻力变化对脉搏波的影响规律。研究表明:随着某分支外周阻力的增加其自身的血流量迅速下降,不同器... 利用55段人体动脉树建立传输线模型,数值仿真人体动脉树中脉搏波的传播,在心脏输出体积流率波一定的条件下,改变模型分支外周阻力来探讨阻力变化对脉搏波的影响规律。研究表明:随着某分支外周阻力的增加其自身的血流量迅速下降,不同器官的阻力比增加均能引起主动脉和桡动脉平均血压的升高,且升高的趋势逐渐减小;当阻力比η=4时,肝、脾、胃、上肠膜、右肾、下肠膜分支桡动脉平均血压较正常分别增加2.86%、4.55%、1.90%、12.15%、9.81%、1.49%。脉搏波谐波与各器官病变之间存在客观联系是中医脉诊的依据,而通过对桡动脉脉搏波频域分析发现,脉搏波谐波振幅与各器官外周阻力变化的联系不明显,仿真时还需考虑不同器官病变时心脏自我调节作用的影响。 展开更多
关键词 动脉树 传输线模型 外周阻力 脉搏波
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Isotopic evidence for the moisture origin and composition of surface runoff in the headwaters of the Heihe River basin 被引量:37
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作者 zhao liangju YIN Li +5 位作者 XIAO HongLang CHENG GuoDong ZHOU MaoXian YANG YongGang LI CaiZhi ZHOU Jian 《Chinese Science Bulletin》 SCIE EI CAS 2011年第4期406-416,共11页
We investigated the moisture origin and contribution of different water sources to surface runoff entering the headwaters of the Heihe River basin on the basis of NECP/NCAR(National Centers for Environmental Predictio... We investigated the moisture origin and contribution of different water sources to surface runoff entering the headwaters of the Heihe River basin on the basis of NECP/NCAR(National Centers for Environmental Prediction/National Center for Atmospheric Research) re-analysis data and variations in the stable hydrogen and oxygen isotope ratios(δ D and δ 18O) of precipitation,spring,river,and melt water. The similar seasonality in precipitation δ 18O at different sites reveals the same moisture origin for water entering the headwaters of the Heihe River basin. The similarity in the seasonality of δ 18O and d-excess for precipitation at Yeniugou and Urumchi,which showed more positive δ 18O and lower d-excess values in summer and more negative δ 18O and higher d-excess values in winter,indicates a dominant effect of westerly air masses in summer and the integrated influence of westerly and polar air masses in winter. Higher d-excess values throughout the year for Yeniugou suggest that in arid inland areas of northwestern China,water is intensively recycled. Temporal changes in δ 18O,δ D,and d-excess reveal distinct contributions of different bodies of water to surface runoff. For example,there were similar trends for δ D,δ 18O,and d-excess of precipitation and river water from June to September,similar δ 18O trends for river and spring water from December to February,and similar trends for precipitation and runoff volumes. However,there were significant differences in δ 18O between melt water and river water in September. Our results show that the recharge of surface runoff by precipitation occurred mainly from June to mid-September,whereas the supply of surface runoff in winter was from base flow(as spring water) ,mostly with a lower runoff amount. 展开更多
关键词 水分来源 地表径流 同位素比值 黑河流域 上游 组成 证据 降水量
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Climatic significance of the stable carbon isotope composition of tree-ring cellulose:Comparison of Chinese hemlock (Tsuga chinensis Pritz) and alpine pine (Pinus densata Mast) in a temperate-moist region of China 被引量:11
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作者 LIU XiaoHong SHAO XueMei +5 位作者 WANG LiLi zhao liangju WU Pu CHEN Tuo QIN DaHe REN JiaWen 《Science China Earth Sciences》 SCIE EI CAS 2007年第7期1076-1085,共10页
In the reconstruction of past climate using stable carbon isotope composition (δ13C) in tree ring,the responses of the stable carbon composition (δ13C) of multiple tree species to environmental factors must be known... In the reconstruction of past climate using stable carbon isotope composition (δ13C) in tree ring,the responses of the stable carbon composition (δ13C) of multiple tree species to environmental factors must be known detailedly. This study presented two δ13C series in annual tree rings for Chinese hem-lock (Tsuga chinensis Pritz) and alpine pine (Pinus densata Mast),and investigated the relationships between climatic parameters and stable carbon discrimination (△13C) series,and evaluated the poten-tial of climatic reconstruction using △13C in both species,in a temperate-moist region of Chuanxi Pla-teau,China. The raw δ13C series of the two species was inconsistent,which may be a result of different responses caused by tree's inherent physiological differences. After removing the low-frequency ef-fects of CO2 concentration,the high-frequency (year-to-year) inter-series correlation of △13C was strong,indicating that △13C of the two tree species were controlled by common environmental conditions. The △13C series of the species were most significantly correlated with temperature and moisture stress,but in different periods and intensity between the species. During the physiological year,the impacts of temperature and moisture stress on △13C occur earlier for Chinese hemlock (previous December to February for moisture stress and February to April for temperature,respectively) than for alpine pine (March to May for moisture stress and April to July for temperature,respectively). In addition,in temperate-moist regions,the control on △13C of single climatic parameter was not strongly dominant and the op-timal multiple regressions functions just explained the 38.5% variance of the total. Therefore,there is limited potential for using δ13C alone to identify clear,reliable climatic signals from two species. 展开更多
关键词 temperate-moist REGION CHINESE HEMLOCK ALPINE PINE inter-specific δ13C variability climatic significance
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Foliar δ^(13)C and δ^(15)N values of C_3 plants in the Ethiopia Rift Valley and their environmental controls 被引量:12
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作者 LIU XiaoHong zhao liangju +3 位作者 GASAW Menassie GAO DengYi QIN DaHe REN JiaWen 《Chinese Science Bulletin》 SCIE EI CAS 2007年第9期1265-1273,共9页
The foliar C and N stable isotopic compositions(δ 13C and δ 15N) and the relationships between these compositions and environmental factors of C3 plants in the Ethiopia Rift Valley were investigated. There were thre... The foliar C and N stable isotopic compositions(δ 13C and δ 15N) and the relationships between these compositions and environmental factors of C3 plants in the Ethiopia Rift Valley were investigated. There were three distribution patterns for foliar δ 13C with mean values of ?26.7‰±0.4‰,?29.7‰± 0.6‰,and ?26.9‰± 1.2‰ in cold-moist,temperate-moist,and arid-hot environments,respectively. The δ 15N values ranged from ?1.4‰± 1.7‰ to 14.3‰± 0.1‰,with higher values under arid-hot conditions and the lowest values in plants growing at higher altitudes under cold-moist conditions. A strong negative relationship between mean annual precipitation and δ 15N explained more than half of the observed variation in the δ 15N values(r2 = 0.54,P < 0.001);a modest positive relationship was also found between δ 15N and tem-perature(r2 = 0.32,P < 0.01). A weakly positive relationship existed between δ 13C and temperature,and changes in δ 13C values with precipitation and altitude followed quadratic curves. This suggests a shift in the effects of water and heat conditions caused by altitude on carbon isotopic discrimination. 展开更多
关键词 埃塞俄比亚裂谷 C3植物 叶片 碳稳定同位素 氮稳定同位素 环境因素
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