期刊文献+
共找到616,528篇文章
< 1 2 250 >
每页显示 20 50 100
Ultra‑High Sensitivity Anisotropic Piezoelectric Sensors for Structural Health Monitoring and Robotic Perception
1
作者 Hao Yin Yanting Li +4 位作者 Zhiying Tian Qichao Li Chenhui Jiang Enfu Liang Yiping Guo 《Nano-Micro Letters》 SCIE EI CAS 2025年第2期432-446,共15页
Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor strugg... Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing systems.However,the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix,and achieving sensitivity for detecting micrometer-scale deformations is also challenging.Herein,we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement,capable of detecting minute anisotropic deformations.The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%,thereby enabling its utility in accurately discerning the 5μm-height wrinkles in thin films and in monitoring human pulse waves.The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase.Additionally,when integrated with machine learning techniques,the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100%accuracy.The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli,offering a novel perspective for enhancing recognition accuracy. 展开更多
关键词 Flexible piezoelectric filaments ANISOTROPIC Ultra-high sensitivity Structural health detection Texture recognition
下载PDF
近红外无创血糖浓度的Label Sensitivity算法和支持向量机回归 被引量:1
2
作者 孟琪 赵鹏 +4 位作者 宦克为 李野 姜志侠 张瀚文 周林华 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第3期617-624,共8页
近红外光谱分析技术在生物医学工程领域具有广阔应用前景。无创且持续性地测量能实时监控人体血糖水平,给糖尿病患者带来极大便利性、提高生存质量、降低糖尿病并发症发生率具有很大的社会效益。无创血糖监测的想法提出较早,但仍然存在... 近红外光谱分析技术在生物医学工程领域具有广阔应用前景。无创且持续性地测量能实时监控人体血糖水平,给糖尿病患者带来极大便利性、提高生存质量、降低糖尿病并发症发生率具有很大的社会效益。无创血糖监测的想法提出较早,但仍然存在预测精度低、预测值与标签值相关性不高等难点,至今没有达到临床要求。近年来,光谱检测技术发展迅猛且机器学习技术在智能信息处理方面具有明显优势,两者结合可以有效提高人体无创血糖医学监测模型的精度和普适性。提出了一种标签敏感度算法(LS),并结合支持向量机方法建立了人体血糖含量预测模型。使用近红外光谱仪采集了4名志愿者食指处动态血液光谱数据(每名志愿者28组数据),并使用多元散射矫正(MSC)方法消除了部分光散射的影响。考虑血糖对不同波长光的吸收有差异,提出了基于血糖浓度标签差的特征波长挑选方法,并构建了标签敏感度支持向量机(LSSVR)预测模型。设计实验,对比该模型与偏最小二乘回归(PLSR)和区分度支持向量机(FSSVR)算法。结果表明,LS算法的最佳特征波长数为32,经特征波长选择后的LSSVR表现最佳,其均方误差降低至0.02 mmol·L^(-1),明显优于全谱段PLSR模型,血糖浓度的预测值与标签值的相关系数提升至99.8%,预测值全部位于可容许误差的克拉克网格A区内。LSSVR模型的优异表现为早日实现血糖的无创监测提供了新思路。 展开更多
关键词 无创血糖 近红外光谱 特征波长 Label sensitivity算法 支持向量机
下载PDF
Identification, pathogenicity, and fungicide sensitivity of Eutiarosporella dactylidis associated with leaf blight on maize in China 被引量:1
3
作者 Cheng Guo Xiaojie Zhang +9 位作者 Baobao Wang Zhihuan Yang Jiping Li Shengjun Xu Chunming Wang Zhijie Guo Tianwang Zhou Liu Hong Xiaoming Wang Canxing Duan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第3期888-900,共13页
Maize(Zea mays L.) is an economically vital grain crop that is cultivated worldwide. In 2011, a maize foliar disease was detected in Lingtai and Lintao counties in Gansu Province, China. The characteristic signs and s... Maize(Zea mays L.) is an economically vital grain crop that is cultivated worldwide. In 2011, a maize foliar disease was detected in Lingtai and Lintao counties in Gansu Province, China. The characteristic signs and symptoms of this disease include irregular chlorotic lesions on the tips and edges of infected leaves and black punctate fruiting bodies in dead leaf tissues. Given favourable environmental conditions, this disease spread to areas surrounding Gansu. In this study, infected leaves were collected from Gansu and Ningxia Hui Autonomous Region between 2018and 2020 to identify the disease-causing pathogen. Based on morphological features, pathogenicity tests, and multilocus phylogenetic analysis involving internal transcribed spacer(ITS), 18S small subunit rDNA(SSU), 28S large subunit rDNA(LSU), translation elongation factor 1-alpha(TEF), and β-tubulin(TUB) sequences, Eutiarosporella dactylidis was identified as the causative pathogen of this newly discovered leaf blight. Furthermore, an in vitro bioassay was conducted on representative strains using six fungicides, and both fludioxonil and carbendazim were found to significantly inhibit the mycelial growth of E. dactylidis. The results of this study provide a reference for the detection and management of Eutiarosporella leaf blight. 展开更多
关键词 maize leaf blight MORPHOLOGY molecular phylogeny Eutiarosporella dactylidis fungicide sensitivity
下载PDF
Future changes in precipitation and water availability over the Tibetan Plateau projected by CMIP6 models constrained by climate sensitivity 被引量:1
4
作者 Hui Qiu Tianjun Zhou +3 位作者 Liwei Zou Jie Jiang Xiaolong Chen Shuai Hu 《Atmospheric and Oceanic Science Letters》 CSCD 2024年第5期40-46,共7页
Precipitation projections over the Tibetan Plateau(TP)show diversity among existing studies,partly due to model uncertainty.How to develop a reliable projection remains inconclusive.Here,based on the IPCC AR6–assesse... Precipitation projections over the Tibetan Plateau(TP)show diversity among existing studies,partly due to model uncertainty.How to develop a reliable projection remains inconclusive.Here,based on the IPCC AR6–assessed likely range of equilibrium climate sensitivity(ECS)and the climatological precipitation performance,the authors constrain the CMIP6(phase 6 of the Coupled Model Intercomparison Project)model projection of summer precipitation and water availability over the TP.The best estimates of precipitation changes are 0.24,0.25,and 0.45 mm d^(−1)(5.9%,6.1%,and 11.2%)under the Shared Socioeconomic Pathway(SSP)scenarios of SSP1–2.6,SSP2–4.5,and SSP5–8.5 from 2050–2099 relative to 1965–2014,respectively.The corresponding constrained projections of water availability measured by precipitation minus evaporation(P–E)are 0.10,0.09,and 0.22 mm d^(−1)(5.7%,4.9%,and 13.2%),respectively.The increase of precipitation and P–E projected by the high-ECS models,whose ECS values are higher than the upper limit of the likely range,are about 1.7 times larger than those estimated by constrained projections.Spatially,there is a larger increase in precipitation and P–E over the eastern TP,while the western part shows a relatively weak difference in precipitation and a drier trend in P–E.The wetter TP projected by the high-ECS models resulted from both an approximately 1.2–1.4 times stronger hydrological sensitivity and additional warming of 0.6℃–1.2℃ under all three scenarios during 2050–2099.This study emphasizes that selecting climate models with climate sensitivity within the likely range is crucial to reducing the uncertainty in the projection of TP precipitation and water availability changes. 展开更多
关键词 Tibetan plateau Climate sensitivity Precipitation projection Water availability projection
下载PDF
Sensitivity of key factors and uncertainties in health risk assessment of benzene pollutant 被引量:8
5
作者 LIU Zhi-quan ZHANG Ying-hua LI Guang-he ZHANG Xu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第10期1272-1280,共9页
Predicting long-term potential human health risks from contaminants in the multimedia environment requires the use of models. However, there is uncertainty associated with these predictions of many parameters which ca... Predicting long-term potential human health risks from contaminants in the multimedia environment requires the use of models. However, there is uncertainty associated with these predictions of many parameters which can be represented by ranges or probability distributions rather than single value. Based on a case study with information from an actual site contaminated with benzene, this study describes the application of MMSOILS model to predict health risk and distributions of those predictions generated using Monte Carlo techniques. A sensitivity analysis was performed to evaluate which of the random variables are most important in producing the predicted distributions of health risks. The sensitivity analysis shows that the predicted distributions can be accurately reproduced using a small subset of the random variables. The practical implication of this analysis is the ability to distinguish between important versus unimportant random variables in terms of their sensitivity to selected endpoints. This directly translates into a reduction in data collection and modeling effort. It was demonstrated that how correlation coefficient could be used to evaluate contributions to overall uncertainty from each parameter. The integrated uncertainty analysis shows that although drinking groundwater risk is similar with inhalation air risk, uncertainties of total risk come dominantly from drinking groundwater route. Most percent of the variance of total risk comes from four random variables. 展开更多
关键词 Monte Carlo sensitivity UNCERTAINTY MMSOILS models risk assessment
下载PDF
Efficient slope reliability and sensitivity analysis using quantile-based first-order second-moment method 被引量:1
6
作者 Zhiyong Yang Chengchuan Yin +2 位作者 Xueyou Li Shuihua Jiang Dianqing Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期4192-4203,共12页
This paper introduces a novel approach for parameter sensitivity evaluation and efficient slope reliability analysis based on quantile-based first-order second-moment method(QFOSM).The core principles of the QFOSM are... This paper introduces a novel approach for parameter sensitivity evaluation and efficient slope reliability analysis based on quantile-based first-order second-moment method(QFOSM).The core principles of the QFOSM are elucidated geometrically from the perspective of expanding ellipsoids.Based on this geometric interpretation,the QFOSM is further extended to estimate sensitivity indices and assess the significance of various uncertain parameters involved in the slope system.The proposed method has the advantage of computational simplicity,akin to the conventional first-order second-moment method(FOSM),while providing estimation accuracy close to that of the first-order reliability method(FORM).Its performance is demonstrated with a numerical example and three slope examples.The results show that the proposed method can efficiently estimate the slope reliability and simultaneously evaluate the sensitivity of the uncertain parameters.The proposed method does not involve complex optimization or iteration required by the FORM.It can provide a valuable complement to the existing approximate reliability analysis methods,offering rapid sensitivity evaluation and slope reliability analysis. 展开更多
关键词 Slope reliability sensitivity analysis QUANTILE First-order second-moment method(FOSM) First-order reliability method(FORM)
下载PDF
Spatiotemporal Characteristics of Reference Evapotranspiration and Its Sensitivity Coefficients to Climate Factors in Huang-Huai-Hai Plain,China 被引量:11
7
作者 YANG Jian-ying LIU Qin +3 位作者 MEI Xu-rong YAN Chang-rong JU Hui XU Jian-wen 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第12期2280-2291,共12页
Climate change will have important implications in water shore regions,such as Huang-Huai-Hai(3H) plain,where expected warmer and drier conditions might augment crop water demand.Sensitivity analysis is important in... Climate change will have important implications in water shore regions,such as Huang-Huai-Hai(3H) plain,where expected warmer and drier conditions might augment crop water demand.Sensitivity analysis is important in understanding the relative importance of climatic variables to the variation in reference evapotranspiration(ET 0).In this study,the 51-yr ET 0 during winter wheat and summer maize growing season were calculated from a data set of daily climate variables in 40 meteorological stations.Sensitivity maps for key climate variables were estimated according to Kriging method and the spatial pattern of sensitivity coefficients for these key variables was plotted.In addition,the slopes of the linear regression lines for sensitivity coefficients were obtained.Results showed that ET 0 during winter wheat growing season accounted for the largest proportion of annual ET 0,due to its long phenological days,while ET 0 was detected to decrease significantly with the magnitude of 0.5 mm yr-1in summer maize growing season.Solar radiation is considered to be the most sensitive and primarily controlling variable for negative trend in ET 0 for summer maize season,and higher sensitive coefficient value of ET 0 to solar radiation and temperature were detected in east part and southwest part of 3H plain respectively.Relative humidity was demonstrated as the most sensitive factor for ET 0 in winter wheat growing season and declining relativity humidity also primarily controlled a negative trend in ET 0,furthermore the sensitivity coefficient to relative humidity increased from west to southeast.The eight sensitivity centrals were all found located in Shandong Province.These ET 0 along with its sensitivity maps under winter wheat-summer maize rotation system can be applied to predict the agricultural water demand and will assist water resources planning and management for this region. 展开更多
关键词 ET 0 spatial distribution temporal trends sensitivity coefficient 3H plain
下载PDF
Assessment of desertification sensitivity using an improved MEDALUS model in Northern China
8
作者 NingJing Tan CaiXia Zhang +1 位作者 YingYing Wu ZhenTing Wang 《Research in Cold and Arid Regions》 CSCD 2024年第3期141-148,共8页
Assessment of land sensitivity to desertification is an important step to support desertification monitoring and control.Based on the Mediterranean Desertification and Land Use(MEDALUS)model,we defined four quality in... Assessment of land sensitivity to desertification is an important step to support desertification monitoring and control.Based on the Mediterranean Desertification and Land Use(MEDALUS)model,we defined four quality indicators(soil,climate,vegetation and management)to evaluate the sensitivity of land in northern China to desertification.We improved MEDALUS via excluding cities from the areas at risk of desertification by means of defining a threshold value for population density.The framework,validated in northern China,further optimizes the model to link priority areas and land restoration programmed to support desertification control.We found that the four indicators influenced and restricted each other,which jointly affected the distribution of desertification sensitivity in northern China.The spatial distribution of sensitivity in northern China showed large regional differences,with clear boundaries and concentrated distributions of regions with high and low sensitivity;the overall sensitivity decreased,with some areas rated as having moderate,severe,and extremely severe sensitivity changing to slight sensitivity;and the influence weight was much higher for the management quality index than for the climate,vegetation,and soil indexes.This suggests that management was the main factor that affected desertification sensitivity in northern China,and that climate factors exacerbated sensitivity,but the factors that are driving the spatial heterogeneity of the influencing factors need further study。 展开更多
关键词 DESERTIFICATION sensitivity MEDALUS factor analysis Northern China
下载PDF
Targeted Mutagenesis of NAC Transcription Factor Gene,OsN AC041,Leading to Salt Sensitivity in Rice 被引量:11
9
作者 WANG Bo ZHONG Zhaohui +10 位作者 ZHANG Huanhuan WANG Xia LIU Binglin YANG Lijia HAN Xiangyan YU Deshui ZHENG Xuelian WANG Chunguo SONG Wenqin CHEN Chengbin ZHANG Yong 《Rice science》 SCIE CSCD 2019年第2期98-108,I0007-I0015,共12页
Salinity is a major abiotic stress factor that seriously affects plant growth. Many genes are involved in the response to salt stress with various metabolism pathways. A number of plant transcription factor family gen... Salinity is a major abiotic stress factor that seriously affects plant growth. Many genes are involved in the response to salt stress with various metabolism pathways. A number of plant transcription factor family genes have been found to be involved in the salt stress response, and NAM, ATAF and CUC(NAC) transcription factors are thought to act as active regulators during abiotic stress, especially salt stress. In this study, we detected a rice NAC transcription factor coding gene, OsNAC041, and confirmed that it influenced the germination of seeds under salt stress and salt tolerance of plants. OsNAC041 was primarily expressed in the leaves and located in the nucleus. Furthermore, the CRISPR/Cas9 method was used to obtain a targeted osnac041 mutant, of which the plant height was higher than that of the wild-type, showing increased salt sensitivity. Moreover, RNA-seq analysis revealed a number of differentially expressed genes(DEGs) involved in several important signaling pathways in the osnac041 mutant. Subsequently, Kyoto Encyclopedia of Genes and Genomes annotation also revealed differential expression of DEGs associated with mitogen-activated protein kinase signaling, peroxisome, eukaryotictype ABC transporters, photosynthesis and plant hormones, which are involved in stress-related signaling pathways. Overall, our study suggested that OsNAC041 was involved in the salt stress response in rice. These findings not only provide empirical evidence of OsNAC041 function, but also provide new insight into its potential application in rice resistance breeding. 展开更多
关键词 RICE NAC TRANSCRIPTION factor CRISPR Cas9 RNA-SEQ SALINITY
下载PDF
Increased expression of brain-derived neurotrophic factor is correlated with visceral hypersensitivity in patients with diarrheapredominant irritable bowel syndrome 被引量:16
10
作者 Yu Zhang Geng Qin +2 位作者 De-Rong Liu Yan Wang Shu-Kun Yao 《World Journal of Gastroenterology》 SCIE CAS 2019年第2期269-281,共13页
BACKGROUND Visceral hypersensitivity is considered to play a vital role in the pathogenesis of irritable bowel syndrome(IBS). Neurotrophins have drawn much attention in IBS recently. Brain-derived neurotrophic factor(... BACKGROUND Visceral hypersensitivity is considered to play a vital role in the pathogenesis of irritable bowel syndrome(IBS). Neurotrophins have drawn much attention in IBS recently. Brain-derived neurotrophic factor(BDNF) was found to mediate visceral hypersensitivity via facilitating sensory nerve growth in pre-clinical studies. We hypothesized that BDNF might play a role in the pathogenesis of diarrhea-predominant IBS(IBS-D).AIM To investigate BDNF levels in IBS-D patients and its role in IBS-D pathophysiology.METHODS Thirty-one IBS-D patients meeting the Rome IV diagnostic criteria and 20 ageand sex-matched healthy controls were recruited. Clinical and psychological assessments were first conducted using standardized questionnaires. Visceral sensitivity to rectal distension was tested using a high-resolution manometry system. Colonoscopic examination was performed and four mucosal pinch biopsies were taken from the rectosigmoid junction. Mucosal BDNF expression and nerve fiber density were analyzed using immunohistochemistry. Mucosal BDNF mRNA levels were quantified by quantitative real-time polymerase chain reaction. Correlations between these parameters were examined.RESULTS The patients had a higher anxiety score [median(interquartile range), 6.0(2.0-10.0) vs 3.0(1.0-4.0), P = 0.003] and visceral sensitivity index score [54.0(44.0-61.0)vs 21.0(17.3-30.0), P < 0.001] than controls. The defecating sensation threshold[60.0(44.0-80.0) vs 80.0(61.0-100.0), P = 0.009], maximum tolerable threshold[103.0(90.0-128.0) vs 182.0(142.5-209.3), P < 0.001] and rectoanal inhibitory reflex threshold [30.0(20.0-30.0) vs 30.0(30.0-47.5), P = 0.032] were significantly lower in IBS-D patients. Intestinal mucosal BDNF protein [3.46 E-2(3.06 E-2-4.44 E-2) vs3.07 E-2(2.91 E-2-3.48 E-2), P = 0.031] and mRNA [1.57(1.31-2.61) vs 1.09(0.74-1.42), P = 0.001] expression and nerve fiber density [4.12 E-2(3.07 E-2-7.46 E-2) vs1.98 E-2(1.21 E-2-4.25 E-2), P = 0.002] were significantly elevated in the patients.Increased BDNF expression was positively correlated with abdominal pain and disease severity and negatively correlated with visceral sensitivity parameters.CONCLUSION Elevated mucosal BDNF may participate in the pathogenesis of IBS-D via facilitating mucosal nerve growth and increasing visceral sensitivity. 展开更多
关键词 IRRITABLE bowel syndrome DIARRHEA BRAIN-DERIVED NEUROTROPHIC factor VISCERAL HYPERsensitivity Nerve growth
下载PDF
MEAN SENSITIVITY AND BANACH MEAN SENSITIVITY FOR LINEAR OPERATORS
11
作者 Quanquan YAO Peiyong ZHU 《Acta Mathematica Scientia》 SCIE CSCD 2024年第4期1200-1228,共29页
Let(X,T)be a linear dynamical system,where X is a Banach space and T:X→X is a bounded linear operator.This paper obtains that(X,T)is sensitive(Li-Yorke sensitive,mean sensitive,syndetically mean sensitive,respectivel... Let(X,T)be a linear dynamical system,where X is a Banach space and T:X→X is a bounded linear operator.This paper obtains that(X,T)is sensitive(Li-Yorke sensitive,mean sensitive,syndetically mean sensitive,respectively)if and only if(X,T)is Banach mean sensitive(Banach mean Li-Yorke sensitive,thickly multi-mean sensitive,thickly syndetically mean sensitive,respectively).Several examples are provided to distinguish between different notions of mean sensitivity,syndetic mean sensitivi`ty and mean Li-Yorke sensitivity. 展开更多
关键词 mean sensitive Banach mean sensitive syndetically mean sensitive Li-Yorke sensitive mean Li-Yorke sensitive
下载PDF
ON THE SENSITIVITY OF THE LDU FACTORIZATION 被引量:1
12
作者 李文军 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2001年第1期79-90,共12页
In this paper,we give the sensitivity analyses by two approaches for L,D,U in factorization A=LDU of general perturbations in A which sufficiently small in norm. By the matrix vector equation approach,we derive the sh... In this paper,we give the sensitivity analyses by two approaches for L,D,U in factorization A=LDU of general perturbations in A which sufficiently small in norm. By the matrix vector equation approach,we derive the sharp condition number for L,D and U factors .By the matrix equation approach we derive corresponding condition estimates. When A is a symmetric matrix,the corresponding results can be obtained for LDL T factorization. 展开更多
关键词 LDU factorization sensitivity condition number condition estimate.
下载PDF
SENSITIVITY FACTORS FOR TYPHOON GENESIS OVER THE WESTERN NORTH PACIFIC DURING JULY-SEPTEMBER 被引量:1
13
作者 吴胜安 李涛 孔海江 《Journal of Tropical Meteorology》 SCIE 2014年第2期112-120,共9页
The paper compares the correlations between individual factors of the cyclogenesis and the number of TCs formed in the western North Pacific in July to September(NTWNP). It also compares the characteristics of zonal a... The paper compares the correlations between individual factors of the cyclogenesis and the number of TCs formed in the western North Pacific in July to September(NTWNP). It also compares the characteristics of zonal anomaly distribution of the factors in the primary TC source areas of the Northern Hemisphere. Results show that the vorticity factor has the closest correlation with NTWNP. In TC genesis conditions, this feature is relatively rich but not enough, which determines that it is the sensitivity factor of NTWNP's annual variation. The paper also analyzes the source of annual variation of the vorticity factor in the key area of the western North Pacific as well as its advantage in showing NTWNP. Results show that the annual variation of the vorticity factor mentioned above is related to the annual variation of Southern Oscillation, Antarctica Oscillation and the geopotential height field of East Australia, which reflects the effect of two large-scale systems in the Southern Hemisphere and ENSO(El Ni?o–Southern Oscillation) on NTWNP. Since the area where the vorticity factor is significantly correlated with NTWNP is consistent with the area of dense TC genesis sources, the vorticity factor has an obvious advantage in showing annual variation of TCs. Those features are very significant for research on the influencing mechanism of NTWNP and simulation of climate models. 展开更多
关键词 statistical characteristics contrastive analysis vorticity factor sensitivity
下载PDF
Runoff characteristics and its sensitivity to climate factors in the Weihe River Basin from 2006 to 2018 被引量:2
14
作者 WU Changxue Xu Ruirui +4 位作者 QIU Dexun DING Yingying GAO Peng MU Xingmin ZHAO Guangju 《Journal of Arid Land》 SCIE CSCD 2022年第12期1344-1360,共17页
Exploring the current runoff characteristics after the large-scale implementation of the Grain for Green(GFG)project and investigating its sensitivities to potential drivers are crucial for water resource prediction a... Exploring the current runoff characteristics after the large-scale implementation of the Grain for Green(GFG)project and investigating its sensitivities to potential drivers are crucial for water resource prediction and management.Based on the measured runoff data of 62 hydrological stations in the Weihe River Basin(WRB)from 2006 to 2018,we analyzed the temporal and spatial runoff characteristics in this study.Correlation analysis was used to investigate the relationships between different runoff indicators and climate-related factors.Additionally,an improved Budyko framework was applied to assess the sensitivities of annual runoff to precipitation,potential evaporation,and other factors.The results showed that the daily runoff flow duration curves(FDCs)of all selected hydrological stations fall in three narrow ranges,with the corresponding mean annual runoff spanning approximately 1.50 orders of magnitude,indicating that the runoff of different hydrological stations in the WRB varied greatly.The trend analysis of runoff under different exceedance frequencies showed that the runoff from the south bank of the Weihe River was more affluent and stable than that from the north bank.The runoff was unevenly distributed throughout the year,mainly in the flood season,accounting for more than 50.00%of the annual runoff.However,the trend of annual runoff change was not obvious in most areas.Correlation analysis showed that rare-frequency runoff events were more susceptible to climate factors.In this study,daily runoff under 10%-20%exceeding frequencies,consecutive maximum daily runoff,and low-runoff variability rate had strong correlations with precipitation,aridity index,and average runoff depth on rainy days.In comparison,daily runoff under 50%-99%exceeding frequencies,consecutive minimum daily runoff,and high-runoff variability rate had weak correlations with all selected impact factors.The sensitivity analysis results suggested that the sensitivity of annual runoff to precipitation was always higher than that to potential evaporation.The runoff about 87.10%of the selected hydrological stations were most sensitive to precipitation changes,and 12.90%were most sensitive to other factors.The spatial pattern of the sensitivity analysis indicated that in relatively humid southern areas,runoff was more sensitive to potential evaporation and other factors,and less sensitive to precipitation. 展开更多
关键词 daily runoff climate-related factors PRECIPITATION potential evaporation correlation analysis sensitivity analysis Weihe River Basin
下载PDF
Temporal variations of reference evapotranspiration and its sensitivity to meteorological factors in Heihe River Basin, China 被引量:6
15
作者 Jie Zhao Zong-xue Xu +1 位作者 De-peng Zuo Xu-ming Wang 《Water Science and Engineering》 EI CAS CSCD 2015年第1期1-8,共8页
On the basis of daily meteorological data from 15 meteorological stations in the Heihe River Basin (HRB) during the period from 1959 to 2012, long-term trends of reference evapotranspiration (ET0) and key meteorol... On the basis of daily meteorological data from 15 meteorological stations in the Heihe River Basin (HRB) during the period from 1959 to 2012, long-term trends of reference evapotranspiration (ET0) and key meteorological factors that affect ET0 were analyzed using the Mann- Kendall test. The evaporation paradox was also investigated at 15 meteorological stations. In order to explore the contribution of key meteo- rological factors to the temporal variation of ET0, a sensitivity coefficient method was employed in this study. The results show that: (1) mean annual air temperature significantly increased at all 15 meteorological stations, while the mean annual ET0 decreased at most of sites; (2) the evaporation paradox did exist in the HRB, while the evaporation paradox was not continuous in space and time; and (3) relative humidity was the most sensitive meteorological factor with regard to the temporal variation of ET0 in the HRB, followed by wind speed, air temperature, and solar radiation. Air temperature and solar radiation contributed most to the temporal variation of ETo in the upper reaches; solar radiation and wind speed were the determining factors for the temporal variation of ET0 in the middle-lower reaches. 展开更多
关键词 Reference evapotranspiration Evaporation paradox Meteorological factor Heihe River Basin
下载PDF
Epidermal growth factor upregulates serotonin transporter and its association with visceral hypersensitivity in irritable bowel syndrome 被引量:11
16
作者 Xiu-Fang Cui Wei-Mei Zhou +4 位作者 Yan Yang Jun Zhou Xue-Liang Li Lin Lin Hong-Jie Zhang 《World Journal of Gastroenterology》 SCIE CAS 2014年第37期13521-13529,共9页
AIM: To investigate the role of epidermal growth factor (EGF) in visceral hypersensitivity and its effect on the serotonin transporter (SERT).
关键词 Epidermal growth factor Visceral hypersensitivity Rat models Serotonin transporter Rat small intestinal epithelial cells Intestinal epithelial cells Irritable bowel syndrome
下载PDF
A sensitivity analysis of factors affecting in geologic CO_(2) storage in the Ordos Basin and its contribution to carbon neutrality 被引量:3
17
作者 Shi-xin Dai Yan-jiao Dong +3 位作者 Feng Wang Zhen-han Xing Pan Hu Fu Yang 《China Geology》 CAS 2022年第3期359-371,共13页
To accelerate the achievement of China’s carbon neutrality goal and to study the factors affecting the geologic CO_(2)storage in the Ordos Basin,China’s National Key R&D Programs propose to select the Chang 6 oi... To accelerate the achievement of China’s carbon neutrality goal and to study the factors affecting the geologic CO_(2)storage in the Ordos Basin,China’s National Key R&D Programs propose to select the Chang 6 oil reservoir of the Yanchang Formation in the Ordos Basin as the target reservoir to conduct the geologic carbon capture and storage(CCS)of 100000 t per year.By applying the basic theories of disciplines such as seepage mechanics,multiphase fluid mechanics,and computational fluid mechanics and quantifying the amounts of CO_(2)captured in gas and dissolved forms,this study investigated the effects of seven factors that influence the CO_(2)storage capacity of reservoirs,namely reservoir porosity,horizontal permeability,temperature,formation stress,the ratio of vertical to horizontal permeability,capillary pressure,and residual gas saturation.The results show that the sensitivity of the factors affecting the gas capture capacity of CO_(2)decreases in the order of formation stress,temperature,residual gas saturation,horizontal permeability,and porosity.Meanwhile,the sensitivity of the factors affecting the dissolution capture capacity of CO_(2)decreases in the order of formation stress,residual gas saturation,temperature,horizontal permeability,and porosity.The sensitivity of the influencing factors can serve as the basis for carrying out a reasonable assessment of sites for future CO_(2)storage areas and for optimizing the design of existing CO_(2)storage areas.The sensitivity analysis of the influencing factors will provide basic data and technical support for implementing geologic CO_(2)storage and will assist in improving geologic CO_(2)storage technologies to achieve China’s carbon neutralization goal. 展开更多
关键词 eologic CO_(2)storage Influencing factors sensitivity analysis Carbon neutrality Oil and gas exploration engineering Ordos Basin China
下载PDF
Characterizing permeability-porosity relationships of porous rocks using a stress sensitivity model in consideration of elastic-structural deformation and tortuosity sensitivity
18
作者 Ronghe Xu Liqin Wang +1 位作者 Xiaoli Zhao Yuze Mao 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第9期3437-3451,共15页
Clarifying the relationship between stress sensitivities of permeability and porosity is of great significance in guiding underground resource mining.More and more studies focus on how to construct stress sensitivity ... Clarifying the relationship between stress sensitivities of permeability and porosity is of great significance in guiding underground resource mining.More and more studies focus on how to construct stress sensitivity models to describe the relationship and obtain a comprehensive stress sensitivity of porous rock.However,the limitations of elastic deformation calculation and incompleteness of considered tortuosity sensitivity lead to the fact that the existing stress sensitivity models are still unsatisfactory in terms of accuracy and generalization.Therefore,a more accurate and generic stress sensitivity model considering elastic-structural deformation of capillary cross-section and tortuosity sensitivity is proposed in this paper.The elastic deformation is derived from the fractal scaling model and Hooke's law.Considering the effects of elastic-structural deformation on tortuosity sensitivity,an empirical formula is proposed,and the conditions for its applicability are clarified.The predictive performance of the proposed model for the permeability-porosity relationships is validated in several sets of publicly available experimental data.These experimental data are from different rocks under different pressure cycles.The mean and standard deviation of relative errors of predicted stress sensitivity with respect to experimental data are 2.63%and 1.91%.Compared with other models,the proposed model has higher accuracy and better predictive generalization performance.It is also found that the porosity sensitivity exponent a,which can describe permeability-porosity relationships,is 2 when only elastic deformation is considered.a decreases from 2 when structural deformation is also considered.In addition,a may be greater than 3 due to the increase in tortuosity sensitivity when tortuosity sensitivity is considered even if the rock is not fractured. 展开更多
关键词 Stress sensitivity model Permeability-porosity relationships Elastic-structural deformation Tortuosity stress sensitivity
下载PDF
Numerical investigation on the sensitivity of jointed rock mass strength to various factors 被引量:14
19
作者 NIU Shuangjian JING Hongwen +1 位作者 HU Kun YANG Dafang 《Mining Science and Technology》 EI CAS 2010年第4期530-534,共5页
The mechanical properties of jointed rock masses, such as strength, deformation and the failure mechanism, can be understood only by studying the sensitivity of jointed rock mass strength (both the peak and residual s... The mechanical properties of jointed rock masses, such as strength, deformation and the failure mechanism, can be understood only by studying the sensitivity of jointed rock mass strength (both the peak and residual strengths) to the factors that affect it. An orthogonal design of uniaxial compression tests was simulated on eighteen groups of jointed rock specimens having different geometric and mechanical properties using RFPA2D (Rock Failure Process Analysis) code. The results show that the peak strength is controlled by the geometric parameters of the joints, but that the residual strength is controlled by the mechanical prop- erties of the joint interfaces. The failure mode of jointed rock specimens is mainly shear failure. Joint quantity, or density, is the most important index that affects jointed rock mass strength and engineering quality. 展开更多
关键词 jointed rock mass peak strength residual strength variance analysis sensitivity
下载PDF
Multi-factor sensitivity analysis of shallow unsaturated clay slope stability 被引量:1
20
作者 ZhuoyingTan MeifengCai 《Journal of University of Science and Technology Beijing》 CSCD 2005年第3期193-202,共10页
An unsaturated clay slope, with various sloping angles and a thickness of 14 m, consists of backfill, slope soil and residual soil. Slide interfaces were determined by geophysical approaches and the original slope was... An unsaturated clay slope, with various sloping angles and a thickness of 14 m, consists of backfill, slope soil and residual soil. Slide interfaces were determined by geophysical approaches and the original slope was reconstructed. Sub-slope masses were classified based on the varieties of sloping angle. A force recursive principle was proposed to calculate the stability coefficient of the sub-slope masses. The influencing factors such as sloping angle, water content, hydrostatic pressure, seismic force as well as train load were analyzed. The range and correlation of the above-mentioned factors were discussed and coupled wave equations were established to reflect the relationships between unit weight, cohesion, internal frictional angle, and water content, as well as between internal frictional angle and cohesion. The sensitivity analysis of slope stability was carried out and susceptive factors were determined when the factors were taken as independent and dependent variables respectively. The results show that sloping angle, water content and earthquake are the principal susceptive factors influencing slope stability. The impact of hydrostatic pressure on slope stability is similar to the seismic force in quantity. Train load plays a small role in slope stability and its influencing only reaches the roadbed and its neighboring slope segment. If the factors are taken as independent variables, the influencing extent of water content and cohesion on slope stability can be weakened and train load can be magnified. 展开更多
关键词 unsaturated clay slope stability multi-factor sensitivity analysis
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部