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Heartbeat and Respiration Rate Prediction Using Combined Photoplethysmography and Ballisto Cardiography
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作者 Valarmathi Ramasamy Dhandapani Samiappan RRamesh 《Intelligent Automation & Soft Computing》 SCIE 2023年第5期1365-1380,共16页
Owing to the recent trends in remote health monitoring,real-time appli-cations for measuring Heartbeat Rate and Respiration Rate(HARR)from video signals are growing rapidly.Photo Plethysmo Graphy(PPG)is a method that ... Owing to the recent trends in remote health monitoring,real-time appli-cations for measuring Heartbeat Rate and Respiration Rate(HARR)from video signals are growing rapidly.Photo Plethysmo Graphy(PPG)is a method that is operated by estimating the infinitesimal change in color of the human face,rigid motion of facial skin and head parts,etc.Ballisto Cardiography(BCG)is a non-surgical tool for obtaining a graphical depiction of the human body’s heartbeat by inducing repetitive movements found in the heart pulses.The resilience against motion artifacts induced by luminancefluctuation and the patient’s mobility var-iation is the major difficulty faced while processing the real-time video signals.In this research,a video-based HARR measuring framework is proposed based on combined PPG and BCG.Here,the noise from the input video signals is removed by using an Adaptive Kalmanfilter(AKF).Three different algorithms are used for estimating the HARR from the noise-free input signals.Initially,the noise-free sig-nals are subjected to Modified Adaptive Fourier Decomposition(MAFD)and then to Enhanced Hilbert vibration Decomposition(EHVD)andfinally to Improved Var-iation mode Decomposition(IVMD)for attaining three various results of HARR.The obtained values are compared with each other and found that the EHVD is showing better results when compared with all the other methods. 展开更多
关键词 Heartbeat rate and respiration rate PHOTOPLETHYSMOGRAPHY BALLISTOCARDIOGRAPHY adaptive kalmanfilter
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THE EFFECTS OF ACUTE PROGRESSIVEHYPOXIA ON THE RESPIRATIONRATE OF THE CHINESE CRABEriocheir sinensis 被引量:5
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作者 邹恩民 堵南山 赖伟 《Zoological Research》 CAS CSCD 1993年第4期327-334,共8页
The effects of acute progressive hypoxia on the respiration rate of the Chinese freshwater crab, Eriocheir sinensis, acclimated at three temperatures were investigated with a closed respiromet er. E. sinensis can main... The effects of acute progressive hypoxia on the respiration rate of the Chinese freshwater crab, Eriocheir sinensis, acclimated at three temperatures were investigated with a closed respiromet er. E. sinensis can maintain its respiration rate down to the critical point (Pc) and from this point its respiration rate declines rapidly, reaching zero at a lower ambient oxygen concentration called the zero respiration oxygen concentration. Because of this, a new hyperbolic equation is introduced to express the relationship between respiration rate and ambient oxygen concentration. A new method for calculating the PC value is also developed. The PC values for E. sinensis at 20-35℃ range from 1.92-3.47 mg/1. 展开更多
关键词 Eriocheir sinensis. Progressive hypoxia respiration rate
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Relationship between oxygen concentration, respiration and filtration rate in blue mussel Mytilus edulis 被引量:1
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作者 TANG Baojun Hans Ulrik RIISGARD 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2018年第2期395-404,共10页
The large water-pumping and particle-capturing gills of the filter-feeding blue mussel Mytilus edulis are oversized for respiratory purposes. Consequently, the oxygen uptake rate of the mussel has been suggested to be... The large water-pumping and particle-capturing gills of the filter-feeding blue mussel Mytilus edulis are oversized for respiratory purposes. Consequently, the oxygen uptake rate of the mussel has been suggested to be rather insensitive to decreasing oxygen concentrations in the ambient water, since the diffusion rate of oxygen from water flowing through the mussel determines oxygen uptake. We tested this hypothesis by measuring the oxygen uptake in mussels exposed to various oxygen concentrations. These concentrations were established via N2-bubbling of the water in a respiration chamber with mussels fed algal cells to stimulate fully opening of the valves. It was found that mussels exposecl to oxygen concentrations decreasing from 9 to 2 mg O2/L resulted in a slow but significant reduction in the respiration rate, while the filtration rate remained high and constant. Thus, a decrease of oxygen concentration by 78% only resulted in a 25% decrease in respiration rate. However, at oxygen concentrations below 2 mg O2/L M. edulis responded by gradually closing its valves, resulting in a rapid decrease of filtration rate, concurrent with a rapid reduction of respiration rate. These observations indicated that M. edulis is no longer able to maintain its normal aerobic metabolism at oxygen concentration below 2 mg O2/L, and there seems to be an energy-saving mechanism in bivalve molluscs to strongly reduce their activity when exposed to low oxygen conditions. 展开更多
关键词 Mytilus edulis filtration rate respiration rate oxygen concentration valve-opening degree
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Human Respiration Rate Estimation Using Ultra-wideband Distributed Cognitive Radar System 被引量:2
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作者 Predrag Rapajic 《International Journal of Automation and computing》 EI 2008年第4期325-333,共9页
It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present... It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture. 展开更多
关键词 Medical and patient monitoring sensing technologies and signal processing vital sign ULTRA-WIDEBAND distributed cog-nitive radar respiration rate estimation.
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Automatic detection of respiratory rate from electrocardiogram,respiration induced plethysmography and 3D acceleration signals 被引量:2
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作者 刘官正 吴丹 +2 位作者 梅占勇 朱青松 王磊 《Journal of Central South University》 SCIE EI CAS 2013年第9期2423-2431,共9页
Respiratory monitoring is increasingly used in clinical and healthcare practices to diagnose chronic cardio-pulmonary functional diseases during various routine activities.Wearable medical devices have realized the po... Respiratory monitoring is increasingly used in clinical and healthcare practices to diagnose chronic cardio-pulmonary functional diseases during various routine activities.Wearable medical devices have realized the possibilities of ubiquitous respiratory monitoring,however,relatively little attention is paid to accuracy and reliability.In previous study,a wearable respiration biofeedback system was designed.In this work,three kinds of signals were mixed to extract respiratory rate,i.e.,respiration inductive plethysmography(RIP),3D-acceleration and ECG.In-situ experiments with twelve subjects indicate that the method significantly improves the accuracy and reliability over a dynamic range of respiration rate.It is possible to derive respiration rate from three signals within mean absolute percentage error 4.37%of a reference gold standard.Similarly studies derive respiratory rate from single-lead ECG within mean absolute percentage error 17%of a reference gold standard. 展开更多
关键词 respiration inductive plethysmography respiratory rate ELECTROCARDIOGRAM 3D acceleration activity
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Characteristics of Soil Respiration of Terraces and Slope Farmland in Loess Hilly and Gully Regions
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作者 Ma Tao Zhou Bo +2 位作者 Chen Aihua Zhang Feng Dong Yanli 《Meteorological and Environmental Research》 CAS 2017年第1期67-70,共4页
Soil CO_2 emissions of terraces and slope farmland in loess hilly and gully regions were measured by using Infra Red Gas Analysis(IRGA),and the diurnal variation characteristics of soil respiration rate in different s... Soil CO_2 emissions of terraces and slope farmland in loess hilly and gully regions were measured by using Infra Red Gas Analysis(IRGA),and the diurnal variation characteristics of soil respiration rate in different slope positions of terraces and slope farmland were analyzed.The results show that the diurnal variation curves of soil respiration rate of terraces and slope farmland in loess hilly and gully regions had a single peak.The soil respiration rate of terraces reached the peak during 13:00-15:00,while the soil respiration rate of slope farmland reached the peak from 11:00 to13:00,and it was the lowest at next 07:00.The daily average of soil respiration rate in slope farmland was 0.86μmol/(m^2·s),accounting for 93.48% of that of terraces.The daily average of soil respiration rate in different slope positions of terraces and slope farmland is shown as follows:the bottom of the slope>the middle of the slope>the top of the slope.At the top of the slope,the daily averages of soil respiration rate in terraces and slope farmland were the same;at the middle and bottom of the slope,the daily average of soil respiration rate in terraces was larger than that of slope farmland. 展开更多
关键词 Soil respiration rate DIURNAL variation CHARACTERISTICS TErrACE Slope farmland Loess HILLY and GULLY regions China
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Relationships between chlorophyll a, bacteria, ATP, POC and respiration rates in the Changjiang Estuary and the plume
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作者 C. Courties G. Cauwet 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1992年第3期425-434,共10页
-Bacteria abundance, chlorophyll a, ATP and POC concentrations and respiration rates of microorganisms in the Changjiang Estuary and the plume were determined in July 1986. The high values of bacteria abundance occurr... -Bacteria abundance, chlorophyll a, ATP and POC concentrations and respiration rates of microorganisms in the Changjiang Estuary and the plume were determined in July 1986. The high values of bacteria abundance occurred in the river mouth in association with suspended matter. It is assumed that bacteria were the major contributor to ATP and the main consumer of dissolved oxygen, and that the relationship between ATP and POC was present in that area. In the dilution zone (salinity; 25-30), instead of bacteria, phytoplankton was the major contributor to ATP and respiration rates, due to diatom bloom. Close relationships between Chi a and ATP, and ATP and POC were observed. Contribution of microbial carbon to POC was also estimated. 展开更多
关键词 POC and respiration rates in the Changjiang Estuary and the plume Relationships between chlorophyll a BACTERIA ATP
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土壤水分含量对旱稻根系和土壤呼吸速率的影响
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作者 赵晨云 王家琪 +5 位作者 赵志平 高桐梅 彭廷 张静 赵亚帆 赵全志 《中国稻米》 北大核心 2024年第3期26-31,共6页
在池栽条件下比较研究了不同土壤水分含量处理(65%WHC、75%WHC、85%WHC、95%WHC和100%WHC,WHC代表田间最大持水量)对旱稻277土壤呼吸速率及根条数的影响。结果表明,土壤水分含量对旱稻土壤呼吸速率和根条数有显著影响。随着土壤水分含... 在池栽条件下比较研究了不同土壤水分含量处理(65%WHC、75%WHC、85%WHC、95%WHC和100%WHC,WHC代表田间最大持水量)对旱稻277土壤呼吸速率及根条数的影响。结果表明,土壤水分含量对旱稻土壤呼吸速率和根条数有显著影响。随着土壤水分含量的提高,土壤呼吸速率显著下降;随着旱稻生育期的推进,除100%WHC处理的土壤呼吸速率减小外,其余水分含量处理的土壤呼吸速率都呈升高趋势;随着土壤水分含量的增加,旱稻根条数逐渐降低,在分蘖前期处理间差异达到显著水平,随着生育期的推进,处理间的差异逐渐减小,且根条数与土壤呼吸速率呈显著正相关关系。土壤呼吸速率日变化在65%WHC、75%WHC和85%WHC处理下表现为逐渐增加后保持稳定,在95%WHC处理下表现为达最大值后逐渐下降,在100%WHC处理下表现为达最大值后略有下降,并一直保持在较低水平。土壤温度日变化在不同土壤水分含量下均呈现先升高再趋于平稳的变化趋势,以75%WHC水分处理下的温度最高,95%WHC和100%WHC水分处理下土壤温度较低。相关分析表明,不同水分含量处理条件下(100%WHC处理除外),土壤呼吸速率与土壤温度呈显著或极显著的二次抛物线关系,根条数与土壤呼吸速率呈显著的正相关关系。 展开更多
关键词 旱稻 土壤水分含量 根条数 土壤温度 土壤呼吸速率
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碳中和背景下的海洋微生物呼吸速率测定方法研究进展
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作者 王延伟 陈晓 +2 位作者 陈骏锋 苏贝 刘纪化 《生态科学》 CSCD 北大核心 2024年第2期234-245,共12页
全球气候变化与人类活动导致的CO_(2)排放息息相关。海洋是净吸收大气CO_(2)的重要环境,因此影响海洋碳存储能力的生物地球化学过程成为研究热点。海洋微生物的呼吸作用是调节碳“源-汇”转换的关键生物过程之一,呼吸速率是海区碳收支... 全球气候变化与人类活动导致的CO_(2)排放息息相关。海洋是净吸收大气CO_(2)的重要环境,因此影响海洋碳存储能力的生物地球化学过程成为研究热点。海洋微生物的呼吸作用是调节碳“源-汇”转换的关键生物过程之一,呼吸速率是海区碳收支研究的重要参照指标。依据不同生物化学原理,海洋领域研发了多种微生物呼吸速率测定方法。依据海洋水文环境和微生物群落等不同应用场景的差异,使得采用一种或多种方法准确测定呼吸速率具有重要意义。文章着重陈述了各种呼吸速率测定的原理、优缺点和适用范围等,系统分析了常规测定方法和前沿测定技术,为碳中和背景下的海洋碳汇关键过程解析提供技术选择的理论支撑。 展开更多
关键词 海洋碳汇 海洋微生物呼吸速率 测定方法 溶解氧 电子传递链
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Stem Respiration of a Larch (Larix gmelini) Plantation in Northeast China 被引量:11
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作者 王文杰 杨逢建 +4 位作者 祖元刚 王慧梅 TAKAGI Kentaro SASA Kaichiro KOIKE Takayoshi 《Acta Botanica Sinica》 CSCD 2003年第12期1387-1397,共11页
Stem respiration is an important part of the activity of a tree and is an important source of CO2 evolution from a forest ecosystem. Presently, no standard methods are available for the accurate estimation of total st... Stem respiration is an important part of the activity of a tree and is an important source of CO2 evolution from a forest ecosystem. Presently, no standard methods are available for the accurate estimation of total stem CO2 efflux from a forest. In the current study, a 33-year-old (by the year 2001) larch (Larix gmelini Rupr.) plantation was measured throughout 2001-2002 to analyze its monthly and seasonal patterns of stem respiration. Stem respiration rate was also measured at different heights, at different daily intervals and any variation in the larch plantation was recorded. The relationship between stem temperature, growth status and respiration rate was analyzed. Higher respiration rates were recorded in upper reaches of the larch tree throughout the season and these were affected partially by temperature difference. Midday depression was found in the diurnal changes in stem respiration. In the morning, but not in the afternoon, stem respiration was positively correlated with stem temperature. The reason for this variation may be attributed to water deficit, which was stronger in the afternoon. In the larch plantation, a maximum 7-fold variation in stem respiration was found. The growth status (such as mean growth rate of stem and canopy projection area) instead of stem temperature difference was positively correlated with this large variation. An S-model (sigmoid curve) or Power model shows the greatest regression of the field data. In the courses of seasonal and annual changes of stem respiration, peak values were observed in July of both years, but substantial interannual differences in magnitude were observed. An exponential model can clearly show this regression of the temperature-respiration relationship. In our results, Q(10) values ranged from 2.22 in 2001 to 3.53 in 2002. Therefore, estimation of total stem CO2 efflux only by a constant Q(10) value may give biased results. More parameters of growth status and water status should be considered for more accurate estimation. 展开更多
关键词 Larix gmelini stem respiration growth status growth rate canopy projection area Q(10)
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不同气调包装对薄荷贮藏品质的影响及薄荷保鲜呼吸速率模型的建立 被引量:1
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作者 陆一菲 张慧娟 +3 位作者 王思文 王国强 李涵睿 陈湘宁 《食品工业科技》 CAS 北大核心 2024年第9期11-25,共15页
为了提高薄荷采后贮藏时间和预测薄荷采后的呼吸速率,通过失重率、相对电导率、色差、感官评分、维生素C含量、总叶绿素含量和菌落总数指标的测定,从包装材料为聚乙烯包装(PE)、邻苯基苯酚复合聚乙烯包装(OPP1.8/PE3.5、OPP1.8/PE4.5、O... 为了提高薄荷采后贮藏时间和预测薄荷采后的呼吸速率,通过失重率、相对电导率、色差、感官评分、维生素C含量、总叶绿素含量和菌落总数指标的测定,从包装材料为聚乙烯包装(PE)、邻苯基苯酚复合聚乙烯包装(OPP1.8/PE3.5、OPP1.8/PE4.5、OPP2.3/PE4.5)、高密度聚乙烯包装(HDPE),O_(2)浓度为3%~7%,CO_(2)浓度为5%~15%中筛选薄荷的气调包装条件,并以O_(2)、CO_(2)和包装材料为因素开展响应面优化试验,优化薄荷采后保鲜的最优气体比例及包装材料,在此基础上研究薄荷挥发性化合物和表面真菌多样性。使用密闭空间系统法测量薄荷在最优包装材料内O_(2)和CO_(2)的比例。在此基础上,再采用渗透系统法得到模型方程,并对其进行数值模拟。运用Matlab软件对处于平衡点时的呼吸速率进行计算,利用二次多项式模型对结果进行回归分析。利用高通量测序对最优、最差和对照处理组的薄荷进行测序和分析,比较其优势菌群的占比变化。结果表明:最优气调比例及包装材料为3.5%O_(2)+9.4%CO_(2)和HDPE,该包装方式可将薄荷的保鲜期由7~9 d延长至10~12 d,可抑制薄荷贮藏期间芳樟醇等醇类物质的增加,减少D-香芹酮等酮类物质的挥发,延缓薄荷衰老,基于以上实验结果建立薄荷二次多项式呼吸速率模型,并能够更准确设计薄荷的气调包装条件,较好地抑制薄荷贮藏期间子囊菌门和霉菌门等腐败菌的生长。 展开更多
关键词 薄荷 气调包装 挥发性成分 呼吸速率模型 贮藏保鲜
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不同温湿指数下奶牛体温、脉搏和呼吸频率的变化规律研究 被引量:1
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作者 周进 李艳 +2 位作者 吴佳颖 苑君君 贺绍君 《黑龙江畜牧兽医》 CAS 北大核心 2024年第12期50-53,共4页
为了探究不同温湿指数(temprature-humidity index,THI)环境下奶牛体温、脉搏、呼吸频率的变化规律,试验以900头荷斯坦奶牛为研究对象,于蚌埠市一年较热的时间,即2022年7月19日至9月16日连续测量奶牛的体温、脉搏、呼吸频率及牛舍干、... 为了探究不同温湿指数(temprature-humidity index,THI)环境下奶牛体温、脉搏、呼吸频率的变化规律,试验以900头荷斯坦奶牛为研究对象,于蚌埠市一年较热的时间,即2022年7月19日至9月16日连续测量奶牛的体温、脉搏、呼吸频率及牛舍干、湿球温度,计算THI,研究THI与奶牛体温、脉搏、呼吸频率的相关性。结果表明:当69≤THI≤79时,奶牛体温在39.2~39.3℃之间波动,脉搏从62次/min升到74次/min,呼吸频率由57次/min升至74次/min;与THI为69时比较,THI为79时奶牛体温差异不显著(P>0.05),脉搏和呼吸频率差异极显著(P<0.01)。当79<THI≤89时,奶牛体温从39.3℃升高到39.6℃,脉搏从74次/min升高到77次/min,呼吸频率从74次/min升高至81次/min;与THI为79时比较,THI为89时奶牛体温、脉搏、呼吸频率均差异不显著(P>0.05)。当89<THI≤93时,奶牛体温从39.6℃升高到40.0℃,脉搏在77~78次/min之间波动,呼吸频率从81次/min升至83次/min;与THI为89时比较,THI为93时奶牛体温差异极显著(P<0.01),脉搏、呼吸频率均差异不显著(P>0.05)。说明当69≤THI≤79时,奶牛脉搏、呼吸频率与THI具有相关性,体温与THI相关性不明显;当79<THI≤89时,奶牛体温、脉搏、呼吸频率均与THI相关性不明显;当89<THI≤93时,奶牛体温与THI具有相关性,脉搏、呼吸频率与THI相关性不明显。 展开更多
关键词 体温 脉搏 呼吸频率 温湿指数(THI) 奶牛
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Soil Carbon Balance in a Native Temperate Grassland in the Xilin River Basin of Inner Mongolia 被引量:3
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作者 李凌浩 韩兴国 +8 位作者 王其兵 白文明 白永飞 闫志丹 陈全胜 张焱 杨晶 李鑫 宋世环 《Acta Botanica Sinica》 CSCD 2002年第6期740-742,共3页
Based on historical data and field investigation, some major fluxes and reserves of carbon were estimated, and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin Rive... Based on historical data and field investigation, some major fluxes and reserves of carbon were estimated, and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin River basin of Inner Mongolia. Major results were reported as follows: 1) Annual average carbon input from above-ground biomass production was 79.8 g C(.)m(-2.)a(-1), and from root biomass to 30 cm. depth averaged 311.9 g C(.)m(-2.)a(-1). The summed mean annual carbon input of shoot and root materials in the study site was approximately 391.7 g C(.)m(-2.)a(-1). 2) The annual amount of above-ground biomass consumed by insects averaged 14.7 g C(.)m(-2.)a(-1), and the carbon output by leaching or light-chemical oxidation was 3.2 g C(.)m(-2.)a(-1) The annual evolution rate of CO2 from net soil respiration averaged 346.9 g C(.)m(-2.)a(-1), and the summed mean annual output was approximately 364.8 g C(.)m(-2.)a(-1). 3) A mature, steady-state system could be assumed for the community for which growth and decay were approximately in balance, with a net carbon accumulation of about 26.9 g C(.)m(-2.)a(-1). Based on the soil organic carbon density of the field, the turnover Irate of soil carbon in 0 - 30 cm depth was calculated to be 6.2%, with a turnover time of 16 years. 展开更多
关键词 Leymus chinensis steppe carbon balance soil respiration turnover rate net primary productivity (NPP)
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不同放牧强度对荒漠草原土壤呼吸速率及其温度敏感性的影响
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作者 宁玉娜 王占义 +4 位作者 高翠萍 吕广一 杨昌祥 张春英 王成杰 《草地学报》 CAS CSCD 北大核心 2024年第10期3233-3240,共8页
在气候变暖影响下,研究放牧对草原土壤呼吸速率(Soil respiration rate,Rs)及其温度敏感性系数(Temperature sensitivity,Q 10)的影响,对阐述草原生态系统碳收支具有重要意义。以荒漠草原为研究对象,设置无牧、轻度放牧和重度放牧3个处... 在气候变暖影响下,研究放牧对草原土壤呼吸速率(Soil respiration rate,Rs)及其温度敏感性系数(Temperature sensitivity,Q 10)的影响,对阐述草原生态系统碳收支具有重要意义。以荒漠草原为研究对象,设置无牧、轻度放牧和重度放牧3个处理,运用全自动变温培养土壤温室气体在线测量系统,测定不同放牧处理区0~30 cm土壤变温(-10~25℃)培养下的呼吸速率并计算Q 10。结果表明:放牧处理9年后的Rs及其Q 10值为:重度放牧Rs显著高于无牧和轻度放牧(P<0.05),重度放牧显著增加0~10 cm土层Q 10值;与无牧相比,轻度放牧显著降低20~30 cm土层Q 10值;主成分分析表明:放牧强度主要影响土壤pH值、粉粒含量,进而影响Rs。轻度放牧可降低土壤呼吸Q 10值,从而减少荒漠草原土壤CO_(2)排放。因此,建议实施轻度放牧管理策略以减少荒漠草原的碳排放。 展开更多
关键词 荒漠草原 放牧强度 土壤呼吸速率 温度敏感性
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模拟增温对植物叶片δ^(13)C值的影响:全球Meta分析
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作者 张莉莉 叶志成 +3 位作者 廖凯华 朱青 赖晓明 郭长强 《生态学报》 CAS CSCD 北大核心 2024年第12期5412-5421,共10页
温室气体大量排放导致的全球变暖是最为关注的环境问题之一,这会直接影响植物的生长与发育进而影响群落组成乃至生态系统的结构和功能。水分利用效率作为植物叶片通过光合作用调节水分生理过程的指标,是联系生态系统碳循环与水循环关系... 温室气体大量排放导致的全球变暖是最为关注的环境问题之一,这会直接影响植物的生长与发育进而影响群落组成乃至生态系统的结构和功能。水分利用效率作为植物叶片通过光合作用调节水分生理过程的指标,是联系生态系统碳循环与水循环关系的关键,反映了植被生态系统对立地环境快速调整和资源变化的适应策略,是当前全球变化研究中的重点。植物叶片碳稳定同位素比值(δ^(13)C)是反映植物长期水分利用效率的关键指标,但全球气候变暖对植物叶片δ^(13)C值的影响仍存在较大争议。该研究利用Meta分析整合全球范围内51份相关研究文献中的371组数据,较为系统地评估模拟增温对植物叶片δ^(13)C及其生理生态指标的影响。结果表明,模拟增温能够使叶片δ^(13)C值显著升高0.6%(P<0.001),同时对叶片呼吸速率R_(d)、气孔导度G_(s)、净光合作用速率P_(n)、碳C的效应值分别为0.237、0.062、-0.140、-0.019 (P<0.05)。模拟增温处理在增强植物光合作用的同时提高了叶片呼吸速率(R_(d)),导致光合产物不断被消耗、叶片碳(C)降低,最终使叶片P_(n)降低并且叶片δ^(13)C产生富集现象。通过进一步对影响因素分析发现,叶片δ^(13)C值对增温的响应主要受增温时间、高程和年均气温等控制(相对重要性指数分别为1.00、0.97和0.92)。另外,模拟增温时选用不同的增温模式对叶片δ^(13)C值也具有显著不同的影响,采用红外线加热、土柱置换和电缆增温等方法对叶片δ^(13)C值具有正向促进作用(效应值分别为0.70、0.44和0.35),而采用遮阳屏与开顶箱增温等方法具有负向作用(效应值分别为-0.17和-0.09)。研究结论对于深入理解全球变化背景下植物水分利用的响应特征具有重要的理论意义,以期为今后该领域的植物生长研究提供理论依据和有效支撑。 展开更多
关键词 模拟增温 叶片δ^(13)C META分析 气孔导度 呼吸速率 植物水分利用效率
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基于改进GOOSE算法的VMD体征信息研究
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作者 刘贵 徐曦 +1 位作者 许中华 谭奥成 《传感器与微系统》 CSCD 北大核心 2024年第9期26-29,共4页
本文中依靠60 GHz调频连续波(FMCW)毫米波雷达,通过改进的GOOSE算法,在种群初始化阶段结合Tent混沌映射,在探索阶段运用Levy飞行策略提升算法的全局搜索能力。然后,通过改进的GOOSE算法去应用到变分模态分解(VMD)中,得到k和α最优值。对... 本文中依靠60 GHz调频连续波(FMCW)毫米波雷达,通过改进的GOOSE算法,在种群初始化阶段结合Tent混沌映射,在探索阶段运用Levy飞行策略提升算法的全局搜索能力。然后,通过改进的GOOSE算法去应用到变分模态分解(VMD)中,得到k和α最优值。对GOOSE算法的改进提高了呼吸心率的检测的精度。最后,该实验结果表明:利用改进的GOOSE优化算法对VMD算法进行参数自适应优化,通过对信号的重构后分析,有效地去除了噪声分量,提高了分解效率。 展开更多
关键词 GOOSE算法 变分模态分解 Tent混沌映射 Levy飞行策略 呼吸 心率
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不同CO_(2)浓度和氮肥水平对稻田呼吸速率的影响
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作者 柯浩楠 曹琰梅 +4 位作者 商东耀 武熳秋 帅斯樑 李琪 胡正华 《农业资源与环境学报》 CAS CSCD 北大核心 2024年第3期567-575,共9页
为研究不同CO_(2)浓度和氮肥水平对稻田呼吸速率的影响,利用12个开顶式气室开展田间试验,CO_(2)浓度设置对照(CK,自由大气CO_(2)浓度)、CO_(2)浓度比CK增加120μmol·mol-1(C1)和200μmol·mol-1(C2)3个水平,氮肥设置低氮(N1,15... 为研究不同CO_(2)浓度和氮肥水平对稻田呼吸速率的影响,利用12个开顶式气室开展田间试验,CO_(2)浓度设置对照(CK,自由大气CO_(2)浓度)、CO_(2)浓度比CK增加120μmol·mol-1(C1)和200μmol·mol-1(C2)3个水平,氮肥设置低氮(N1,15 g·m^(-2))和常规氮肥(N2,25 g·m^(-2))2个水平,试验共6种处理。结果表明:在相同施氮水平下,在灌浆期和蜡熟期,C1N1比CKN1处理的呼吸速率分别下降了23.4%(P=0.045)和49.1%(P=0.010);在抽穗期和灌浆期,C2N2比CKN2处理的呼吸速率分别升高了12.3%(P=0.009)和16.8%(P=0.047)。同一CO_(2)浓度下,不同施氮水平处理的呼吸速率表现为N2>N1,且在拔节期和抽穗期达到显著水平,在灌浆期达到极显著水平;其中在灌浆期和蜡熟期,C1N1比C1N2处理的呼吸速率分别下降了31.1%(P=0.004)和42.7%(P=0.010)。研究表明,大气CO_(2)浓度升高对稻田呼吸速率的影响因生育时期而异,氮肥减施可以降低稻田呼吸速率及CO_(2)累积释放量。 展开更多
关键词 CO_(2)浓度 氮肥 呼吸速率 稻田 静态暗箱 气相色谱
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美托洛尔对伴长RR间期的持续性心房颤动患者的影响 被引量:10
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作者 崔晶 董建增 +7 位作者 杜昕 闫倩 宁曼 徐霞 蒋晨曦 康俊萍 刘小慧 马长生 《中国心脏起搏与心电生理杂志》 2012年第5期389-393,共5页
目的评价美托洛尔在伴长RR间期(RR间期>1.5 s)的持续性心房颤动(简称房颤)患者中应用的疗效及安全性。方法 100例持续性房颤伴RR间期>1.5 s的患者,采用美托洛尔25 mg每日2次,治疗2周。观察治疗前后24 h和清醒状态时有RR间期≥2.5 ... 目的评价美托洛尔在伴长RR间期(RR间期>1.5 s)的持续性心房颤动(简称房颤)患者中应用的疗效及安全性。方法 100例持续性房颤伴RR间期>1.5 s的患者,采用美托洛尔25 mg每日2次,治疗2周。观察治疗前后24 h和清醒状态时有RR间期≥2.5 s的患者比率,最长RR间期、平均心室率、最大心室率、最小心室率及心率变异性(HRV)的时域参数[24 h RR间期均值的标准差(SDNN)、相邻RR间期差值均方根(RMSSD)]和频域参数[高频(HF)、低频成分(LF)]。结果除3例自发转复为窦性心律,1例应用地高辛,1例失访外,最终入选95例。治疗后,最长RR间期从2 200±540(1 500~3 520)ms延长到2 400±490(1 510~3 560)ms(P<0.001);平均心室率、最大心室率、最小心室率均显著降低(79.78±13.31次/分vs 93.67±15.74次/分,151.82±25.08次/分vs 175.64±24.32次/分,40.78±9.79次/分vs 47.04±11.49次/分,P均<0.01);SDNN、RMSSD、HF和LF均显著增加(233.9±40.8 ms vs 209.7±54.2 ms,270.1±74.0 ms vs 240.2±40.8 ms,18 572.2±6 667.4 ms2 vs 13 997.0±5 491.3 ms2,11 373.7±4 486.6 ms2 vs 8 599.4±3 669.3 ms2,P均<0.01);全天有RR间期≥2.5s的患者,治疗前后无差异[36.8%(35/95)vs 28.4%(27/95),P>0.05];清醒状态有RR间期≥2.5 s的患者,治疗后较治疗前无明显增多[8.4%(8/95)vs 6.3%(6/95),P>0.05]。无近似晕厥及晕厥等不良事件发生。结论对于有β受体阻滞剂适应证伴有长RR间期的持续性房颤患者,口服美托洛尔仍然是安全有效的。 展开更多
关键词 心血管病学 持续性心房颤动 rr间期 心室率控制 美托洛尔
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应用集合卡尔曼滤波算法对土壤呼吸速率同化及NEP估算
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作者 贾科 于颖 +1 位作者 杨曦光 范文义 《东北林业大学学报》 CAS CSCD 北大核心 2024年第7期77-84,110,共9页
为了对净生态系统生产力(NEP)进行准确估算,以长白山通量观测站观测数据为基础,构建土壤温度、湿度耦合因子的更新模型(线性函数、指数函数、二次式函数),结合集合卡尔曼滤波算法(EnKF)获取高精度土壤呼吸速率数据,应用陆地生态系统碳... 为了对净生态系统生产力(NEP)进行准确估算,以长白山通量观测站观测数据为基础,构建土壤温度、湿度耦合因子的更新模型(线性函数、指数函数、二次式函数),结合集合卡尔曼滤波算法(EnKF)获取高精度土壤呼吸速率数据,应用陆地生态系统碳循环综合模型(InTEC模型)准确估算NEP。结果表明:二次式模型的EnKF算法同化结果估算效果最好,决定系数(R^(2))为0.782,均方根误差为52.90 g·m^(-2)·a^(-1);指数模型EnKF算法同化结果估算值的R^(2)为0.755,均方根误差为56.47 g·m^(-2)·a^(-1);线性模型EnKF算法同化结果估算值的R^(2)为0.742,均方根误差为62.80 g·m^(-2)·a^(-1)。选取二次式模型优化后的土壤呼吸速率数据,InTEC模型模拟长白山通量观测站长时间序列净生态系统生产力的R^(2)为0.900,均方根误差为61.77 g·m^(-2)·a^(-1);InTEC模型模拟东北三省森林生态系统2003—2010年的净生态系统生产力年均值,由初始模拟的30.07 g·m^(-2)·a^(-1),经EnKF算法更新后提升到176.87 g·m^(-2)·a^(-1)。因此,采用EnKF更新土壤温度-湿度耦合因子获取的土壤呼吸速率数据,能够提高InTEC模型估算NEP的精度,为大区域尺度森林生态系统NEP估算提供技术支持。 展开更多
关键词 集合卡尔曼滤波算法 土壤温湿度 陆地生态系统碳循环综合模型 净生态系统生产力 土壤呼吸速率
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不同经营措施对马占相思人工林土壤呼吸的影响
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作者 曾伟 罗栋 +2 位作者 史正军 包江桥 张小凤 《东北林业大学学报》 CAS CSCD 北大核心 2024年第7期58-63,共6页
以马占相思(Acacia mangium)人工林为研究对象,探讨间伐、皆伐、“皆伐+补种”、“间伐+补种”、封山育林等不同森林经营管理措施对马占相思人工林土壤呼吸的影响,明确影响土壤呼吸的关键环境因子。结果表明:采伐强度(间伐、皆伐、封山... 以马占相思(Acacia mangium)人工林为研究对象,探讨间伐、皆伐、“皆伐+补种”、“间伐+补种”、封山育林等不同森林经营管理措施对马占相思人工林土壤呼吸的影响,明确影响土壤呼吸的关键环境因子。结果表明:采伐强度(间伐、皆伐、封山育林)、补种均对土壤呼吸速率产生显著影响,土壤呼吸速率从大到小依次为:间伐样地((3.36±0.05)μmol·m^(-2)·s^(-1))、皆伐样地((3.10±0.07)μmol·m^(-2)·s^(-1))、封山育林对照样地((2.83±0.07)μmol·m^(-2)·s^(-1));而补种后的样地土壤呼吸速率((2.73±0.06)μmol·m^(-2)·s^(-1))小于未补种样地((3.34±0.05)μmol·m^(-2)·s^(-1));不同经营管理措施的样地平均呼吸速率从大到小依次为:皆伐、“间伐+补种”、间伐、封山育林对照、“皆伐+补种”。间伐、皆伐后的林地土壤温度显著高于对照样地,而补种对土壤温度没有显著的影响。森林经营管理措施可以改变土壤呼吸速率对温度的敏感性系数(Q_(10)值)。森林经营管理措施对土壤营养元素产生显著影响,封山育林对照样地的土壤营养元素质量分数最高,“间伐+补种”样地最低。因此,在林业生产实践中,可采取合理的经营措施提升森林质量和调控森林碳循环过程。 展开更多
关键词 土壤呼吸速率 森林经营措施 土壤温度 采伐模式
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