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A new model describing Forbush Decreases at Mars: combining the heliospheric modulation and the atmospheric influence 被引量:1
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作者 Jingnan Guo Robert FWimmer-Schweingruber +2 位作者 Mateja Dumbović Bernd Heber YuMing Wang 《Earth and Planetary Physics》 CSCD 2020年第1期62-72,共11页
Forbush decreases are depressions in the galactic cosmic rays (GCRs) that are caused primarily by modulations of interplanetary coronal mass ejections (ICMEs) but also occasionally by stream/corotating interaction reg... Forbush decreases are depressions in the galactic cosmic rays (GCRs) that are caused primarily by modulations of interplanetary coronal mass ejections (ICMEs) but also occasionally by stream/corotating interaction regions (SIRs/CIRs). Forbush decreases have been studied extensively using neutron monitors at Earth;recently, for the first time, they have been measured on the surface of another planet, Mars, by the Radiation Assessment Detector (RAD) on board the Mars Science Laboratory’s (MSL) rover Curiosity. The modulation of GCR particles by heliospheric transients in space is energy-dependent;afterwards, these particles interact with the Martian atmosphere, the interaction process depending on particle type and energy. In order to use ground-measured Forbush decreases to study the space weather environment near Mars, it is important to understand and quantify the energy-dependent modulation of the GCR particles by not only the pass-by heliospheric disturbances but also by the Martian atmosphere. Accordingly, this study presents a model that quantifies both at the Martian surface and in the interplanetary space near Mars the amplitudes of Forbush decreases at Mars during the pass-by of an ICME/SIR by combining the heliospheric modulation of GCRs with the atmospheric modification of such modulated GCR spectra. The modeled results are in good agreement with measurements of Forbush decreases caused by ICMEs/SIRs based on data collected by MSL on the surface of Mars and by the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft in orbit. Our model and these findings support the validity of both the Forbush decrease description and Martian atmospheric transport models. 展开更多
关键词 ICME and Forbush decreases space weather at Mars Mars:atmosphere GCR radiation
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Impact of CR Forbush Decreases on Upper Atmospheric Pressure and Temperature in Saudi Arabia
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作者 Maghrabi Abdullrahman Alghamdi Rasha +1 位作者 Aldosari Abdulah Almutairy Mohammed 《Atmospheric and Climate Sciences》 2025年第1期200-217,共18页
The objective of this research is to investigate the effects of cosmic ray Forbush Decreases (FDs) exceeding 7% in magnitude, occurring between 1985 and 2016, on upper atmospheric pressure and temperature at Abha and ... The objective of this research is to investigate the effects of cosmic ray Forbush Decreases (FDs) exceeding 7% in magnitude, occurring between 1985 and 2016, on upper atmospheric pressure and temperature at Abha and Tabouk. Employing the super epoch analysis method, the study concentrated on altitudes of 5 km and 10 km, uncovering significant variations. Seasonal and synoptic-scale variations were considered and excluded when necessary across eight 9-day periods. Both locations showed considerable fluctuations in pressure and temperature before and after the events. At 5 km altitude (21 events), Abha experienced more pressure increases both before (9 vs. 7) and after (12 vs. 11) the events compared to Tabouk. For temperature, Abha recorded more increases before the events (5 vs. 1), while Tabouk showed more decreases (19 vs. 15). Post-event, Tabouk had more temperature increases (13 vs. 10). At 10 km altitude (20 events), both regions experienced more decreases than increases in pressure and temperature before the events and more increases afterward. Notably, Abha experienced more pressure increases both 4 days before (9 vs. 7) and after the events (12 vs. 11) than Tabouk. For temperature, Abha recorded more increases before the events (5 vs. 1), while Tabouk showed more decreases (19 vs. 15). Post-event, Tabouk had more temperature increases (13 vs. 10). These findings underscore both similarities and differences in atmospheric responses to FDs between Abha and Tabouk. Both locations exhibited cooling trends before and warming trends after the events, with Tabouk demonstrating a more pronounced warming trend post-event. These results enhance our understanding of the atmospheric dynamics linked to FDs and assist in predicting weather patterns associated with these phenomena. 展开更多
关键词 Forbush Decrease Upper Air Temperature Saudi Arabia Climate Change Solar Activity
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Analysis of Forbush decreases observed using a muon telescope in Antarctica starting on 21 June 2015
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作者 De-Hong Huang Hong-Qiao Hu +4 位作者 Ji-Long Zhang Hong Lu Da-Li Zhang Bin-Shen Xue Jing-Tian Lu 《Chinese Physics C》 SCIE CAS CSCD 2018年第12期140-150,共11页
A cosmic-ray muon telescope the telescope was built in the Zhongshan has been collecting data since the end Station of Antarctica. The telescope of 2014, which was shortly after is the first observation device to be b... A cosmic-ray muon telescope the telescope was built in the Zhongshan has been collecting data since the end Station of Antarctica. The telescope of 2014, which was shortly after is the first observation device to be built by Chinese scientists in Antarctica. The pressure change is very strong in Zhongshan station. The count rate of the pressure correction results shows that the large variations in the count rate are likely caused by pressure fluctuations. During the period from 18 June to 22 June 2015, four halo coronal mass ejections (CMEs) were ejected from the Sun. These CMEs initiated a series of Forbush decreases (FD) when they reached the Earth. We conducted a comprehensive study of the intensity fluctuations of galactic cosmic rays recorded during FDs. The intensity fluctuations used in this study were collected by cosmic ray detectors of multiple stations (Zhongshan, McMurdo, South Polar, and Nagoya), and the solar wind measurements were collected by ACE and WIND. The profile of the FD of 22 June demonstrated a four-step decrease. The traditional one- or two-step FD classification method does not adequately explain the FD profile results. The interaction between the faster CME that occurred on 21 June 2015 and the two slow CMEs of the earlier few days should be considered. The cosmic ray intensities of the South Pole, McMurdo, and Zhongshan stations have similar hourly variations, whereas the galactic cosmic rays recorded between polar and non-polar locations are distinct. The FD pre-increase of 22 June 2015 for the Nagoya ninon telescope (non-polar location) lags those of the McMurdo and Zhongshan stations (polar locations) by 1 h. The FD onset of 22 June 2015 for the Nagoya muon telescope lags those of the polar locations by 1 h. 展开更多
关键词 cosmic ray muon telescope neutron monitor CME Forbush decrease
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Multi-strategy improved honey badger algorithm based on periodic mutation and t-distribution perturbation
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作者 WU Jin SU Zhengdong +2 位作者 TIAN Jinhang WEN Fei CHEN Wenfeng 《High Technology Letters》 2025年第1期63-72,共10页
The honey badger algorithm(HBA),as a new swarm intelligence(SI)optimization algorithm,has shown certain effectiveness in its applications.Aiming at the problems of unsatisfactory initial population distribution of HBA... The honey badger algorithm(HBA),as a new swarm intelligence(SI)optimization algorithm,has shown certain effectiveness in its applications.Aiming at the problems of unsatisfactory initial population distribution of HBA,poor ability to avoid local optimum,and slow convergence speed,this paper proposes a multi-strategy improved HBA based on periodical mutation and t-distribution perturbation,called MHBA.Firstly,a good point set population initialization is introduced to get a uniform initial population.Secondly,periodic mutation and t-distribution perturbation are successively used to improve the algorithm’s ability to avoid local optimum.Finally,the density factor is improved for balancing exploration and exploitation.By comparing MHBA with HBA and 7 other SIs on 6 benchmark functions,it is evident that the performance of MHBA is far superior to HBA.In addition,by applying MHBA to robot path planning,MHBA can identify the shortest path more quickly and consistently compared with competitors. 展开更多
关键词 periodic mutation T-DISTRIBUTION linear decreasing factor robot path planning
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Cellular senescence and other age-related mechanisms in skeletal diseases
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作者 Ke Li Sihan Hu Hao Chen 《Bone Research》 2025年第4期806-825,共20页
Cellular senescence and its senescence-associated secretory phenotype(SASP)represent a pivotal role in the development of skeletal diseases.Targeted elimination or rejuvenation of senescent cells has shown potential a... Cellular senescence and its senescence-associated secretory phenotype(SASP)represent a pivotal role in the development of skeletal diseases.Targeted elimination or rejuvenation of senescent cells has shown potential as a therapeutic strategy to reverse age-related skeletal senescence and promote bone regeneration.Meanwhile,other age-related mechanisms,involving altered cellular functions,impaired intercellular crosstalk,disturbed tissue microenvironment,and decreased regenerative capacity,synergistically contribute to the pathogenesis.In this review,we outline the cellular senescence and other age-related mechanisms in developing skeletal diseases,including osteoporosis,intervertebral disc degeneration,osteoarthritis,rheumatoid arthritis,bone tumors and ankylosing spondylitis,with the aim of comprehensively understanding their detrimental effects on the aged skeleton and screening the potential targets for anti-aging therapy within the skeletal system. 展开更多
关键词 senescence associated secretory phenotype cellular senescence osteoarthritis decreased regenerative capacitysynergistically intervertebral disc degeneration altered cellular functionsimpaired osteoporosis rheumatoid arthritis
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Global change factors cause decoupling of nutrient dynamics and asynchrony between microbial communities and ecological functions in a temperate grassland soil
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作者 Yuqian LI Junwei MA +2 位作者 Yijia LI Xinyi SHEN Xinghui XIA 《Pedosphere》 2025年第4期627-640,共14页
Soil microbial communities and grassland ecosystem processes are increasingly confronted with multiple global change factors(GCFs).There is still a lack of research on how these multiple GCFs interact and impact soil ... Soil microbial communities and grassland ecosystem processes are increasingly confronted with multiple global change factors(GCFs).There is still a lack of research on how these multiple GCFs interact and impact soil microbial communities and their functions.To address this gap,we conducted a simulation experiment to examine the individual and interactive effects of the four most critical and prevalent GCFs,elevated carbon dioxide concentration(eCO_(2)),elevated temperature(eT),decreased precipitation(dP),and elevated nitrogen(N)deposition(eN).This study focused on their effects on soil physicochemical properties,bacterial and fungal communities,and extracellular enzyme activities(EEAs)related to carbon(C),N,and phosphorus(P)cycles in a temperate grassland.Results showed that eCO_(2),eN,and dP tended to increase EEAs,while having neutral effects on microbial diversity and community composition.On the other hand,eT resulted in decreases in soil pH,total C,total N,EEAs,and microbial diversity,but increases in plant biomass,total P,microbial richness,and network complexity and stability.This shift in the nutrient limitation from P to N under warming conditions resulted in decoupling of nutrients.Neutral or slightly negative relationships were found between enzyme activities and microbial richness,diversity,and dominant species,and the responses of microbial communities and ecological functions were asynchronous under GCFs.Importantly,our results revealed significant higher-order interactions among GCFs and found that they had notable effects on soil physicochemical properties as well as on microbial communities and ecological functions.These findings provide valuable insights and suggestions for ecological adaptations to future global changes. 展开更多
关键词 decreased precipitation elevated carbon dioxide concentration elevated nitrogen deposition elevated temperature higher-order interaction soil enzymes soil microbiota soil nutrients
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Impact of aerosol-radiation interaction and heterogeneous chemistry on the winter decreasing PM_(2.5)and increasing O_(3)in Eastern China 2014–2020
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作者 Yasong Li Tijian Wang +4 位作者 Qin’geng Wang Mengmeng Li Yawei Qu Hao Wu Min Xie 《Journal of Environmental Sciences》 2025年第5期469-483,共15页
In the context of the prevalent winter air quality issues in China marked by declining PM_(2.5)and rising O_(3),this study employed amodified WRF-Chem model to examine the aerosol radiation interaction(ARI),heterogene... In the context of the prevalent winter air quality issues in China marked by declining PM_(2.5)and rising O_(3),this study employed amodified WRF-Chem model to examine the aerosol radiation interaction(ARI),heterogeneous chemistry(AHC),and their combined impact(ALL)on the variations in O_(3)and PM_(2.5)during the 2014–2020 in eastern China.Our analysis confirmed that ARI curtailed O_(3)while elevating PM_(2.5).AHC reduced O_(3)through heterogeneous absorption of NOx and hydroxideswhile notably fostering fine-grained sulfate,resulting in a PM_(2.5)increase.Emission reductions mitigated the inhibitory impact of ARI on meteorological fields and photolysis rates.Emission reduction individually without aerosol feedback led to a 5.43 ppb O_(3)increase and a 22.89μg/m^(3)PM_(2.5)decrease.ARI and AHC amplified the emission-reduction-induced(ERI)O_(3)rise by 1.83 and 0.31 ppb,respectively.The response of ARI to emission diminution brought about a modest PM_(2.5)increase of 0.31μg/m^(3).Conversely,AHC,acting as the primary contributor,caused a noteworthy PM_(2.5)decrease of 4.60μg/m^(3).As efforts concentrate on reducing PM_(2.5),the promotion of ARI on PM_(2.5)counterbalanced the efficacy of emission reduction and the AHC-induced strengthening of PM_(2.5)decrease.The ALL magnified the ERI O_(3)increase by 38.9%and PM_(2.5)decrease by 18.7%.Sensitivity experiments with different degrees of emission reduction demonstrated a consistent linear relationship between the ALL-induced enhancement of O_(3)increase and PM_(2.5)decrease to the ERI PM_(2.5)decline.Our investigation revealed the complex connection between emissions and aerosol feedback in influencing air quality. 展开更多
关键词 Aerosol-radiation interaction Heterogeneous chemistry O_(3)increase PM_(2.5)decrease Emission reduction
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Potential Effect of Short Video Usage Intensity on Short Video Addiction, Perceived Mood Enhancement (‘TikTok Brain’), and Attention Control among Chinese Adolescents
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作者 Jian-Hong Ye Junpeng Zheng +1 位作者 Weiguaju Nong Xiantong Yang 《International Journal of Mental Health Promotion》 2025年第3期271-286,共16页
Objectives:Short video addiction has emerged as a significant public health issue in recent years,with a growing trend toward severity.However,research on the causes and impacts of short video addiction remains limite... Objectives:Short video addiction has emerged as a significant public health issue in recent years,with a growing trend toward severity.However,research on the causes and impacts of short video addiction remains limited,and understanding of the variable“TikTok brain”is still in its infancy.Therefore,based on the Stimulus-Organism-Behavior-Consequence(SOBC)framework,we proposed six research hypotheses and constructed a model to explore the relationships between short video usage intensity,TikTok brain,short video addiction,and decreased attention control.Methods:Given that students are considered a high-risk group for excessive short video use,we collected 1086 valid participants from Chinese student users,including 609 males(56.1%)and 477 females(43.9%),with an average participant age of 19.84 years,to test the hypotheses.Results:(1)Short video usage intensity was positively related to short video addiction,TikTok brain,and decreased attention control;(2)TikTok brain was positively related to short video addiction and decreased attention control;and(3)Short video addiction was positively related to decreased attention control.Conclusions:These findings suggest that although excessive use of short video applications brings negative consequences,users still spend significant amounts of time on these platforms,indicating a need for strict self-regulation of usage time. 展开更多
关键词 Decreased attention control short video addiction excessive short video use stimulus-organism-behavior-consequence(SOBC)framework TikTok addiction TikTok brain
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Mouse model of anti-RANKL discontinuation reveals reduced bone mass and quality through disruption of bone remodeling
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作者 Koji Ishikawa Soji Tani +8 位作者 Nobuhiro Sakai Yoshifumi Kudo Hideyo Horiuchi Hiromi Kimura-Suda Masamichi Takami Mayumi Tsuji Katsunori Inagaki Yuji Kiuchi Takako Negishi-Koga 《Bone Research》 2025年第4期1001-1014,共14页
The discontinuation of denosumab[antibody targeting receptor activator of nuclear factor kappa B ligand(RANKL)]therapy may increase the risk of multiple vertebral fractures;however,the underlying pathophysiology is la... The discontinuation of denosumab[antibody targeting receptor activator of nuclear factor kappa B ligand(RANKL)]therapy may increase the risk of multiple vertebral fractures;however,the underlying pathophysiology is largely unknown.In patients who underwent discontinuation after multiple injections of denosumab,the levels of tartrate-resistant acid phosphatase 5b increased compared to pretreatment levels,indicating a phenomenon known as“overshoot.”The rate of decrease in bone mineral density during the withdrawal period was higher than the rate of decrease associated with aging,suggesting that the physiological bone metabolism had broken down.Overshoot and significant bone loss were also observed in mice receiving continuous administration of anti-RANKL antibody after treatment was interrupted,resembling the original pathology.In mice long out of overshoot,bone resorption recovered,but osteoblast numbers and bone formation remained markedly reduced.The bone marrow exhibited a significant reduction in stem cell(SC)antigen 1-and platelet-derived growth factor receptor alpha-expressing osteoblast progenitors(PαS cells)and alkaline phosphatase-positive early osteoblasts.Just before the overshoot phase,the osteoclast precursor cell population expands and RANKL-bearing extracellular vesicles(EVs)became abundant in the serum,leading to robust osteoclastogenesis after cessation of anti-RANKL treatment.Thus,accelerated bone resorption due to the accumulation of RANKLbearing EVs and long-term suppression of bone formation uncoupled from bone resorption leads to the severe bone loss characteristic of denosumab discontinuation. 展开更多
关键词 vertebral fractureshoweverthe decrease bone mineral density bone mass tartrate resistant acid phosphatase b mouse model anti RANKL discontinuation bone remodeling bone quality
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Weight loss induced bone loss:mechanism of action and clinical implications
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作者 Hanghang Liu Bolun Li +2 位作者 Linyi Liu Wangyang Ying Clifford J.Rosen 《Bone Research》 2025年第6期1327-1341,共15页
Weight loss,whether resulting from disease-related conditions or intentional interventions,has been increasingly recognized as a significant risk factor for compromised skeletal integrity.While moderate weight reducti... Weight loss,whether resulting from disease-related conditions or intentional interventions,has been increasingly recognized as a significant risk factor for compromised skeletal integrity.While moderate weight reduction may yield metabolic benefits,rapid or sustained weight loss is frequently associated with decreased bone mineral density,deterioration of bone microarchitecture,and heightened fracture risk.The mechanisms underlying weight loss–induced bone loss are complex and multifactorial.Emerging evidence highlights a range of contributing factors,including reduced mechanical loading,increased bone marrow adiposity,hormonal and endocrine alterations,nutritional deficiencies,and disruptions in energy metabolism.These mechanisms are intricately interconnected,ultimately impairing bone remodeling and homeostatic balance.In this review,we provide a comprehensive analysis of the current literature on the mechanistic pathways,clinical consequences,and therapeutic strategies related to weight loss–induced bone loss.We further differentiate the skeletal effects of disease-associated versus interventioninduced weight loss,with a focus on their distinct molecular underpinnings.Our goal is to offer novel insights into the optimization of bone health management in the context of weight loss,guided by a translational medicine perspective. 展开更多
关键词 bone loss weight loss induced decreased bone mineral densitydeterioration bone microarchitectureand weight reduction weight losswhether mechanism action weight loss compromised skeletal integritywhile
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Exploring High Dimensional Feature Space With Channel-Spatial Nonlinear Transforms for Learned Image Compression
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作者 Wen Tan Fanyang Meng +2 位作者 Chao Li Youneng Bao Yongsheng Liang 《CAAI Transactions on Intelligence Technology》 2025年第4期1235-1253,共19页
Nonlinear transforms have significantly advanced learned image compression(LIC),particularly using residual blocks.This transform enhances the nonlinear expression ability and obtain compact feature representation by ... Nonlinear transforms have significantly advanced learned image compression(LIC),particularly using residual blocks.This transform enhances the nonlinear expression ability and obtain compact feature representation by enlarging the receptive field,which indicates how the convolution process extracts features in a high dimensional feature space.However,its functionality is restricted to the spatial dimension and network depth,limiting further improvements in network performance due to insufficient information interaction and representation.Crucially,the potential of high dimensional feature space in the channel dimension and the exploration of network width/resolution remain largely untapped.In this paper,we consider nonlinear transforms from the perspective of feature space,defining high-dimensional feature spaces in different dimensions and investigating the specific effects.Firstly,we introduce the dimension increasing and decreasing transforms in both channel and spatial dimensions to obtain high dimensional feature space and achieve better feature extraction.Secondly,we design a channel-spatial fusion residual transform(CSR),which incorporates multi-dimensional transforms for a more effective representation.Furthermore,we simplify the proposed fusion transform to obtain a slim architecture(CSR-sm),balancing network complexity and compression performance.Finally,we build the overall network with stacked CSR transforms to achieve better compression and reconstruction.Experimental results demonstrate that the proposed method can achieve superior ratedistortion performance compared to the existing LIC methods and traditional codecs.Specifically,our proposed method achieves 9.38%BD-rate reduction over VVC on Kodak dataset. 展开更多
关键词 high dimensional feature space learned image compression nonlinear transform the dimension increase and decrease
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Optimal control of wireless energy transfer system via decreasing frequency 被引量:2
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作者 谭林林 黄学良 +1 位作者 周亚龙 赵俊峰 《Journal of Southeast University(English Edition)》 EI CAS 2013年第3期259-263,共5页
In order to solve the multiple power extreme value point problem caused by system frequency splitting during wireless energy transmission at short distances a transmission model of the system is established.With the c... In order to solve the multiple power extreme value point problem caused by system frequency splitting during wireless energy transmission at short distances a transmission model of the system is established.With the comprehensive consideration of the resonance frequency load parameters and the coupling between coils the internal factors of frequency splitting and boundary conditions are discussed.The results show that under the condition of the fixed load the higher the natural resonance frequency the easier the frequency splitting. As the frequency splitting occurs the frequency of the maximum power transfer is no longer with the natural resonance frequency which can make the system unstable and the transfer power more difficult to control. Therefore a decreasing-frequency method is proposed to avoid the system frequency splitting. And decreasing the system resonance frequency can make the system successfully withdraw the frequency splitting area at a short-distance range.Under the fixed load condition the transmission power of the system can be increased by 400% and the transmission efficiency is reduced by only 14% which greatly improves the transmission performance of the system. 展开更多
关键词 optimal control wireless energy transfer decreasing frequency
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固溶温度对激光立体成形GH4169高温合金组织和性能的影响(英文) 被引量:29
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作者 刘奋成 林鑫 +3 位作者 赵卫卫 赵晓明 陈静 黄卫东 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2010年第9期1519-1524,共6页
研究激光立体成形GH4169高温合金固溶处理后的组织,分析了固溶过程中合金元素的均匀化,并对材料显微硬度的变化做了讨论。结果表明,随固溶温度的升高,材料的晶界越来越清晰,经1000-1170°C固溶处理1h后材料发生再结晶,当固溶处理温... 研究激光立体成形GH4169高温合金固溶处理后的组织,分析了固溶过程中合金元素的均匀化,并对材料显微硬度的变化做了讨论。结果表明,随固溶温度的升高,材料的晶界越来越清晰,经1000-1170°C固溶处理1h后材料发生再结晶,当固溶处理温度高于1100°C,有大量孪晶出现,晶粒相比沉积态显著细化,晶粒尺寸约200μm。合金元素的均匀化在1100°C保温1h后基本完成。显微硬度测试结果显示,材料的显微硬度值随固溶温度的升高而降低,在固溶温度低于1100°C时减小趋势较快,高于1100°C时减小趋势减缓。显微硬度的变化与材料中γ′和γ"相及δ相的形态和数量有关。1100°C是激光立体成形GH4169合金比较合适的固溶处理温度下限。 展开更多
关键词 固溶温度 激光立体成形 GH4169高温合金 组织 性能 Microstructures and Properties solution treatment 显微硬度值 固溶处理 材料 chemical composition temperature range 合金元素 grain boundaries microstructure 均匀化 GH4169合金 low limit decreases 温度下限
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一种自负载降速率包列可用带宽测量算法 被引量:1
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作者 张大陆 胡治国 +1 位作者 朱安奇 张俊生 《软件学报》 EI CSCD 北大核心 2012年第2期335-351,共17页
基于自负载周期流技术,提出一种采用降速率包列的可用带宽测量方法SLDRT(self-loading decreasing rate train),并全面分析了该算法在多跳网络、突发性背景流的环境下的性能.SLDRT采用单条包列即可实现对可用带宽的高速测量,具备单次采... 基于自负载周期流技术,提出一种采用降速率包列的可用带宽测量方法SLDRT(self-loading decreasing rate train),并全面分析了该算法在多跳网络、突发性背景流的环境下的性能.SLDRT采用单条包列即可实现对可用带宽的高速测量,具备单次采样、准确测量的特性,可通过调整递减因子等参数,提高测量精度,降低测量负载.理论分析和不同背景流场景下的实验结果表明:在多跳、突发性背景流下,SLDRT具有较强的健壮性;与pathChirp,Pathload算法相比,不仅测量精度优良,而且大量缩短了测量时间,减轻了因测量而引入的额外负载. 展开更多
关键词 网络测量 可用带宽 多跳路径 突发背景流 SLDRT(self-loading DECREASING RATE train)
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TG6钛合金的热稳定性及其在高温下的部分恢复(英文) 被引量:10
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作者 蔡建明 黄旭 +1 位作者 曹春晓 马济民 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2010年第11期1893-1898,共6页
测试了TG6钛合金盘锻件STA状态+再经600℃,100h试样热暴露在不同温度下的拉伸性能。TG6钛合金随着温度升高,抗拉强度下降,塑性提高。在室温下,与STA状态试样相比,经热暴露后的试样拉伸塑性显著降低,而当测试温度在150℃以上时,试样热暴... 测试了TG6钛合金盘锻件STA状态+再经600℃,100h试样热暴露在不同温度下的拉伸性能。TG6钛合金随着温度升高,抗拉强度下降,塑性提高。在室温下,与STA状态试样相比,经热暴露后的试样拉伸塑性显著降低,而当测试温度在150℃以上时,试样热暴露后的拉伸塑性显著提高,亦即热稳定性得到很大程度的恢复。引起TG6钛合金热稳定性下降的主要因素是有序α2相的共格析出和表面氧化。在150℃以上的高温条件下,热稳定性的恢复归因于位错滑移模式的变化,随着温度的升高,由位错剪切α2相的集中平面滑移逐渐向位错交滑移转变,促进位错更为均匀的滑移,从而提高塑性,表现在断口上为宏观的平面形向波浪形断裂特征的转变。 展开更多
关键词 钛合金盘 热稳定性 高温 恢复 High TEMPERATURE thermal stability titanium alloy plastic deformation 热暴露 TENSILE properties TEMPERATURE rising decreases TEMPERATURE RISES 温度升高 位错 拉伸塑性 试样 平面滑移 TENSILE strength room TEMPERATURE
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Long-term albumin infusion improves survival in patients with cirrhosis and ascites: An unblinded randomized trial 被引量:27
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作者 Roberto Giulio Romanelli Giorgio La Villa +8 位作者 Giuseppe Barletta Francesco Vizzutti Fabio Lanini Umberto Arena Vieri Boddi Roberto Tarquini Pietro Pantaleo Paolo Gentilini Giacomo Laffi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第9期1403-1407,共5页
AIM: To investigate the effects of long-term albumin administration on survival, recurrence of ascites and onset of other complications. METHODS: One hundred consecutive patients admitted for first-onset ascites wer... AIM: To investigate the effects of long-term albumin administration on survival, recurrence of ascites and onset of other complications. METHODS: One hundred consecutive patients admitted for first-onset ascites were randomized to receive diuretics plus human albumin 25 g/wk in the first year and 25 g every two wk thereafter (group 1) or diuretics alone (group 2). The primary endpoint was survival without liver transplantation. Secondary endpoints were recurrence of ascites and occurrence of other complications. RESULTS: Median follow-up was 84 (2-120) mo. Albu- min-treated patients had significantly greater cumulative survival rate (Breslow test= 7.05, P= 0.0078) and lower probability of ascites recurrence (51% versus 94%, P〈0.0001). Chronic albumin infusion resulted in a mean increase in survival of 16 mo. CONCLUSION: Long-term albumin administration after first-onset ascites significantly improves patients' survival and decreases the risk of ascites recurrence. 展开更多
关键词 Long-term albumin administration after first-onset ascites significantly improves patients' survival and decreases the risk of ascites recurrence.
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Improved hybrid iterative optimization method for seismic full waveform inversion
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作者 王义 董良国 刘玉柱 《Applied Geophysics》 SCIE CSCD 2013年第3期265-277,357,358,共15页
In full waveform inversion (FWI), Hessian information of the misfit function is of vital importance for accelerating the convergence of the inversion; however, it usually is not feasible to directly calculate the He... In full waveform inversion (FWI), Hessian information of the misfit function is of vital importance for accelerating the convergence of the inversion; however, it usually is not feasible to directly calculate the Hessian matrix and its inverse. Although the limited memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) or Hessian-free inexact Newton (HFN) methods are able to use approximate Hessian information, the information they collect is limited. The two methods can be interlaced because they are able to provide Hessian information for each other; however, the performance of the hybrid iterative method is dependent on the effective switch between the two methods. We have designed a new scheme to realize the dynamic switch between the two methods based on the decrease ratio (DR) of the misfit function (objective function), and we propose a modified hybrid iterative optimization method. In the new scheme, we compare the DR of the two methods for a given computational cost, and choose the method with a faster DR. Using these steps, the modified method always implements the most efficient method. The results of Marmousi and overthrust model testings indicate that the convergence with our modified method is significantly faster than that in the L-BFGS method with no loss of inversion quality. Moreover, our modified outperforms the enriched method by a little speedup of the convergence. It also exhibits better efficiency than the HFN method. 展开更多
关键词 Full waveform inversion Hessian information limited memory BFGS method Hessian-free inexact Newton method decrease ratio
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NUMERICAL SIMULATION STUDY ON WUQING GEOTHERMAL RESERVOIR,TIANJIN
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作者 李新国 赵军 《Transactions of Tianjin University》 EI CAS 2001年第3期197-201,共5页
In this paper the computer code of AUTOUGH2 is used to carry out numerical simulation study on the Wuqing geothermal reservoir for evaluating reservoir performance upon different exploitation schemes.The simulating ca... In this paper the computer code of AUTOUGH2 is used to carry out numerical simulation study on the Wuqing geothermal reservoir for evaluating reservoir performance upon different exploitation schemes.The simulating calculation and analysis of two main cases,production without reinjection and production with reinjection,were carried out to illuminate and compare the temperature and pressure profiles with distance and time.The water level or pressure will decrease with the time of production,and the reinjection will cause the cooling effect of reinjection on the production zone. 展开更多
关键词 numerical simulation AUTOUGH2 RESERVOIR water level decrease pressure decrease REINJECTION cooling effect
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Indicative Significance of ENSO for Summer Precipitation in Liaoning Province
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作者 王大钧 徐智鑫 胡春丽 《Meteorological and Environmental Research》 CAS 2010年第8期102-104,共3页
Based on the summer precipitation data from 53 stations in Liaoning Province and sea surface temperature(SST) data of Hadley Center in 1961-2009,the decadal variation of the relationship between summer precipitation a... Based on the summer precipitation data from 53 stations in Liaoning Province and sea surface temperature(SST) data of Hadley Center in 1961-2009,the decadal variation of the relationship between summer precipitation and SST over Nino3 oceanic regions in the previous autumn was studied.The results showed that their correlation was decreased obviously in recent 30 years.In 1961-1974,summer rainfall could be forecasted according to the SST anomaly over Nino3 oceanic regions in the previous autumn,and there were above 25 stations with the sign accuracy of over 66.7%.However,there were only five stations with the same accuracy during 1980-2009.From 1961 to 1974,25 stations showed block distribution in the central and northeastern Liaoning,but the distribution of five stations was spotty in 1980-2009.Before the middle and latter half of the 1970s,Liaoning had more(less) summer rainfall when SST over the equatorial central and eastern Pacific was higher(lower) in the previous autumn.However,it was difficult to build indicative relationship above since 1980s. 展开更多
关键词 ENSO Summer precipitation DECREASE China
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Harris Hawks Algorithm Incorporating Tuna Swarm Algorithm and Differential Variance Strategy
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作者 XU Xiaohan YANG Haima +4 位作者 ZHENG Heqing LI Jun LIU Jin ZHANG Dawei HUANG Hongxin 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2023年第6期461-473,共13页
Because of the low convergence accuracy of the basic Harris Hawks algorithm,which quickly falls into the local optimal,a Harris Hawks algorithm combining tuna swarm algorithm and differential mutation strategy(TDHHO)i... Because of the low convergence accuracy of the basic Harris Hawks algorithm,which quickly falls into the local optimal,a Harris Hawks algorithm combining tuna swarm algorithm and differential mutation strategy(TDHHO)is proposed.The escape energy factor of nonlinear periodic energy decline balances the ability of global exploration and regional development.The parabolic foraging approach of the tuna swarm algorithm is introduced to enhance the global exploration ability of the algorithm and accelerate the convergence speed.The difference variation strategy is used to mutate the individual position and calculate the fitness,and the fitness of the original individual position is compared.The greedy technique is used to select the one with better fitness of the objective function,which increases the diversity of the population and improves the possibility of the algorithm jumping out of the local extreme value.The test function tests the TDHHO algorithm,and compared with other optimization algorithms,the experimental results show that the convergence speed and optimization accuracy of the improved Harris Hawks are improved.Finally,the enhanced Harris Hawks algorithm is applied to engineering optimization and wireless sensor networks(WSN)coverage optimization problems,and the feasibility of the TDHHO algorithm in practical application is further verified. 展开更多
关键词 Harris Hawks optimization nonlinear periodic energy decreases differential mutation strategy wireless sensor networks(WSN)coverage optimization results
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