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On the functions of astrocyte-mediated neuronal slow inward currents 被引量:2
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作者 Balázs Pál 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第12期2602-2612,共11页
Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events a... Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events are significantly slower than the excitatory postsynaptic currents.Parameters of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto rs.Astrocytes are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback loop.Mostly as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological conditions.There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level.These events often occur in synchro ny on neurons located in the same astrocytic domain.Besides synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity.In addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory inputs.Of note,there might be important regionspecific differences in the roles and actions triggering slow inward currents.In greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological ones.Slow inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural networks.Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes.These events are related to epilepsy,but also found in Alzheimer's disease,Parkinson's disease,and stroke,leading to the decline of cognitive functions.Events with features overlapping with slow inward currents(excitatory,N-methyl-Daspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke,traumatic brain injury,or epilepsy.One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation.However,to state this,more experimental evidence from greater neuronal networks or the level of the individual is needed.In this review,I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it. 展开更多
关键词 ASTROCYTE cortical spreading depolarization gliotransmission GLUTAMATE neural synchronization NMDA receptor paroxysmal depolarizational shift slow inward current
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Identification and fine mapping of qSW2 for leaf slow wilting in soybean 被引量:1
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作者 Shengyou Li Changling Wang +5 位作者 Chunjuan Yan Xugang Sun Lijun Zhang Yongqiang Cao Wenbin Wang Shuhong Song 《The Crop Journal》 SCIE CSCD 2024年第1期244-251,共8页
Drought is one of the abiotic stresses limiting the production of soybean(Glycine max).Elucidation of the genetic and molecular basis of the slow-wilting(SW)trait of this crop offers the prospect of its genetic improv... Drought is one of the abiotic stresses limiting the production of soybean(Glycine max).Elucidation of the genetic and molecular basis of the slow-wilting(SW)trait of this crop offers the prospect of its genetic improvement.A panel of 188 accessions and a set of recombinant inbred lines produced from a cross between cultivars Liaodou 14 and Liaodou 21 were used to identify quantitative-trait loci(QTL)associated with SW.Plants were genotyped by Specific-locus amplified fragment sequencing and seedling leaf wilting was assessed under three water-stress treatments.A genome-wide association study identified 26 SW-associated single-nucleotide polymorphisms(SNPs),including three located in a 248-kb linkage-disequilibrium(LD)block on chromosome 2.Linkage mapping revealed a major-effect QTL,qSW2,associated with all three treatments and adjacent to the LD block.Fine mapping in a BC_(2)F_(3) population derived from a backcross between Liaodou 21 and R26 confined qSW2 to a 60-kb interval.Gene expression and sequence variation analysis identified the gene Glyma.02 g218100,encoding an auxin transcription factor,as a candidate gene for qSW2.Our results will contribute significantly to improving drought-resistant soybean cultivars by providing genetic information and resources. 展开更多
关键词 Drought GWAS Linkage mapping slow wilting Soybean(Glycine max)
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Transferable adversarial slow feature extraction network for few-shot quality prediction in coal-to-ethylene glycol process
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作者 Cheng Yang Chao Jiang +2 位作者 Guo Yu Jun Li Cuimei Bo 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第7期258-271,共14页
In the coal-to-ethylene glycol(CTEG)process,precisely estimating quality variables is crucial for process monitoring,optimization,and control.A significant challenge in this regard is relying on offline laboratory ana... In the coal-to-ethylene glycol(CTEG)process,precisely estimating quality variables is crucial for process monitoring,optimization,and control.A significant challenge in this regard is relying on offline laboratory analysis to obtain these variables,which often incurs substantial monetary costs and significant time delays.The resulting few-shot learning scenarios present a hurdle to the efficient development of predictive models.To address this issue,our study introduces the transferable adversarial slow feature extraction network(TASF-Net),an innovative approach designed specifically for few-shot quality prediction in the CTEG process.TASF-Net uniquely integrates the slowness principle with a deep Bayesian framework,effectively capturing the nonlinear and inertial characteristics of the CTEG process.Additionally,the model employs a variable attention mechanism to identify quality-related input variables adaptively at each time step.A key strength of TASF-Net lies in its ability to navigate the complex measurement noise,outliers,and system interference typical in CTEG data.Adversarial learning strategy using a min-max game is adopted to improve its robustness and ability to model irregular industrial data accurately and significantly.Furthermore,an incremental refining transfer learning framework is designed to further improve few-shot prediction performance achieved by transferring knowledge from the pretrained model on the source domain to the target domain.The effectiveness and superiority of TASF-Net have been empirically validated using a real-world CTEG dataset.Compared with some state-of-the-art methods,TASF-Net demonstrates exceptional capability in addressing the intricate challenges for few-shot quality prediction in the CTEG process. 展开更多
关键词 Chemical process Neural networks slowness principle Transfer learning Prediction
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Tunable phonon-photon coupling induces double magnomechanically induced transparency and enhances slow light in an atom-opto-magnomechanical system
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作者 M'bark Amghar Noura Chabar Mohamed Amazioug 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第12期196-202,共7页
We theoretically investigate the magnomechanically induced transparency phenomenon,Fano resonance and the slow-fast light effect in the situation where an atomic ensemble is placed inside the hybrid cavity of an optom... We theoretically investigate the magnomechanically induced transparency phenomenon,Fano resonance and the slow-fast light effect in the situation where an atomic ensemble is placed inside the hybrid cavity of an optomagnomechanical system.The system is driven by dual optical and phononic drives.We show double magnomechanically induced transparency in the probe output spectrum by exploiting the phonon-photon coupling strength.Then,we study the effects of the decay rate of the cavity and the atomic ensemble on magnomechanically induced transparency.In addition,we demonstrate that effective detuning of the cavity field frequency changes the transparency window from a symmetrical to an asymmetrical profile,resembling Fano resonances.Further,the fast and slow light effects in the system are explored.We show that the slow light profile is enhanced by adjusting the phonon-photon coupling strength.This result may have potential applications in quantum information processing and communication. 展开更多
关键词 cavity magnomechanics magnomechanically induced transparency Fano resonance absorption DISPERSION transmission slow light fast light
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Prediction and critical transition mechanism for granite fracture:Insights from critical slowing down theory
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作者 WANG Chun-lai ZHOU Bao-kun +6 位作者 LI Chang-feng WEN Zhi-jie BAI Zhi-an ZHU Chao-yang SUN Liang XUE Xu-hui CAO Peng 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2748-2764,共17页
Rock fracture warning is one of the significant challenges in rock mechanics.Many true triaxial and synchronous acoustic emission(AE)tests were conducted on granite samples.The investigation focused on the characteris... Rock fracture warning is one of the significant challenges in rock mechanics.Many true triaxial and synchronous acoustic emission(AE)tests were conducted on granite samples.The investigation focused on the characteristics of AE signals preceding granite fracture,based on the critical slowing down(CSD)theory.The granite undergoes a transition from the stable phase to the fracture phase and exhibits a clear CSD phenomenon,characterized by a pronounced increase in variance and autocorrelation coefficient.The variance mutation points were found to be more identifiable and suitable as the primary criterion for predicting precursor information related to granite fracture,compared to the autocorrelation coefficient.It is noteworthy to emphasize that the CSD factor holds greater potential in elucidating the underlying mechanisms responsible for the critical transition of granite fracture,in comparison to the AE timing parameters.Furthermore,a novel multi-parameter collaborative prediction method for rock fracture was developed by comprehensively analyzing predictive information,including abnormal variation modes and the CSD factor of AE characteristic parameters.This method enhances the understanding and prediction of rock fracture-related geohazards. 展开更多
关键词 GRANITE triaxial compression acoustic emission rock fracture critical slowing down theory
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Structure-controlled slow dynamics in Al−Mg melts
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作者 Fei-qi HUANG Xiao-dan WANG +6 位作者 Lin-si-tong HUANG Ju-rui MA Yu-jun JIANG Hua-shan LIU Jin-liang HU Hai-long PENG Bo ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第11期3471-3485,共15页
Molecular dynamics simulation was employed to investigate the dynamical and structural properties of Al−Mg melts with the Al concentration systematically changed.The results show that the viscosity of Al67Mg33 abnorma... Molecular dynamics simulation was employed to investigate the dynamical and structural properties of Al−Mg melts with the Al concentration systematically changed.The results show that the viscosity of Al67Mg33 abnormally surpasses that of Al85Mg15 below 550 K,inconsistent with the tendency at high temperatures.The evolution of the icosahedral order population is found to account for this dynamic behavior.Structural analysis shows a preferred bonding between Al and Mg atoms in the nearest neighbor shells,while a repelling tendency between them in the second shells,leading to the prepeak emergence in the partial static structure factors.The formation of icosahedral clusters is constrained in the Al-rich compositions because of the lack of sufficient Mg atoms to stabilize the clusters geometrically.These results demonstrate the structural consequence through the interplay between geometric packing and chemical interaction.These findings are crucial to understanding the structure−dynamic properties in Al−Mg melts. 展开更多
关键词 Al−Mg melt slow dynamics chemically ordered structure topologically ordered structure molecular dynamics simulation
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Topological slow light and rainbow trapping of surface wave in valley photonic crystal bounded by air
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作者 Shuheng Chen Yi Qi +2 位作者 Yucen Li Qihao Wang Yuanjiang Xiang 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第11期462-466,共5页
Topological slow light and rainbow trapping tend to rely on large-scale interface structure in previous research work,which have restricted further miniaturization.In this work,we propose a method to realize slow ligh... Topological slow light and rainbow trapping tend to rely on large-scale interface structure in previous research work,which have restricted further miniaturization.In this work,we propose a method to realize slow light and rainbow trapping at the zigzag edge of a single valley photonic crystals(VPCs)bounded by air,which is very different from previous studies where rainbow trapping is supported at the interface separating two VPCs with inversion symmetry.By constructing the VPC–air boundaries and VPC–VPC interfaces experimentally,we have observed the topologically protected rainbow trapping simultaneously at the external and internal boundary.This work provides a feasible platform for the miniaturized optical communication devices such as optical buffers,optical storage and optical routing. 展开更多
关键词 topological slow light rainbow trapping valley photonic crystals
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Preservation of superior rectal artery in laparoscopic colectomy:The best choice for slow transit constipation?
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作者 Yi-Lei Liu Wei-Cheng Liu 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第7期2362-2364,共3页
Laparoscopic colectomy with ileorectal anastomosis may be beneficial for patients with slow transit constipation who do not respond to conservative treatment,particularly if the superior rectal artery(SRA)is preserved... Laparoscopic colectomy with ileorectal anastomosis may be beneficial for patients with slow transit constipation who do not respond to conservative treatment,particularly if the superior rectal artery(SRA)is preserved.Several important concerns have been addressed in this commentary.It is important to first go over the definition of surgical procedure as it is used in this text.Second,the current study lacked a control group that had SRA preservation.Thirdly,it would be best to use a prospective,randomized controlled study.Lastly,a description of the mesenteric defect’s state following a laparoscopic colectomy is necessary. 展开更多
关键词 Laparoscopic colectomy slow transit constipation Ileorectal anastomosis Superior rectal artery Anastomotic leak
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Flow field analysis and particle erosion of tunnel-slope systems under coupling between runoff and fast (slow) seepage
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作者 Shuai Zhang Danqing Song +3 位作者 Ruiliang Zhang Kai Zhang Qi Zhao Suraksha Sharma 《Deep Underground Science and Engineering》 2024年第4期385-398,共14页
The presence of particles on the surface of a tunnel slope renders it susceptible to erosion by waterflow,which is a major cause of soil and water loss.In this study,a nonlinear mathematical model and a mechanical equi... The presence of particles on the surface of a tunnel slope renders it susceptible to erosion by waterflow,which is a major cause of soil and water loss.In this study,a nonlinear mathematical model and a mechanical equilibrium model are developed to investigate the distribution offlowfields and particle motion characteristics of tunnel slopes,respectively.The mathematical model offlowfields comprises three parts:a runoff region,a highly permeable soil layer,and a weakly permeable soil layer.The Navier‒Stokes equation controlsfluid motion in the runoff region,while the Brinkman-extended Darcy equation governs fast and slow seepage in the highly and weakly permeable soil layers,respectively.Analytical solutions are derived for the velocity profile and shear stress expression of the modelflowfield under the boundary condition of continuous transition of velocity and stress at thefluid‒solid interface.The shear stress distribution shows that the shear stress at the tunnel-slope surface is the largest,followed by the shear stress of the soil interface,indicating that particles in these two locations are most vulnerable to erosion.A mechanical equilibrium model of sliding and rolling of single particles is established at thefluid‒solid interface,and the safety factor of particle motion(sliding and rolling)is derived.Sensitivity analysis shows that by increasing the runoff depth,slope angle,and soil permeability,the erosion of soil particles will be aggravated on the tunnel-slope surface,but by increasing the particle diameter,particle-specific gravity,and particle stacking angle,the erosion resistance ability of the tunnel-slope surface particles will be enhanced.This study can serve as a reference for the analysis of surface soil and water loss in tunnel-slope systems. 展开更多
关键词 particle erosion particle motion runoff-fast(slow)seepage coupling shear stress profile tunnel-slope system velocity profile
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In Vitro Slow Growth Preservation of Vaccinium uliginosum
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作者 Dai Zhiguo Zhang Youlai +4 位作者 Yang Lie Li Hongmei Li Zheng Gao Qingyu Zhang Bingxiu 《Journal of Northeast Agricultural University(English Edition)》 CAS 2024年第4期31-45,共15页
As an important wild blueberry resource,Vaccinium uliginosum has attracted more and more attention.At present,the wild resources are under destruction.The conservation of wild Vaccinium uliginosum resources is imminen... As an important wild blueberry resource,Vaccinium uliginosum has attracted more and more attention.At present,the wild resources are under destruction.The conservation of wild Vaccinium uliginosum resources is imminent.However,there are few researches on the protection and preservation of its germplasm resources.In vitro preservation is an important method for germplasm conservation.In this study,one strain of wild Vaccinium uliginosum was used as material.The effects of temperature(25℃,15℃,10℃,or 0℃),media(WPM,1/2WPM or 1/3WPM),medium supplements(sorbitol or mannose),and photoperiod(8,10,12,or 14 h•d^(-1))on the growth,survival rate and rejuvenation rate of the plantlets were studied.The physiological changes of plantlets during preservation were analyzed.Methylation-sensitive amplified polymorphism(MSAP)analysis of genomic DNA methylation of plantlets was carried out to explore the genetic stability of the plantlets after preservation.The research results provided a theoretical basis for the germplasm preservation of Vaccinium uliginosum. 展开更多
关键词 Vaccinium uliginosum L. slow growth in vitro preservation methylation-sensitive amplified polymorphism
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Preliminary Discussion on Research Progress and Prospect of Slow Released Fertilizers 被引量:7
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作者 陈勋 王红娟 +2 位作者 杨先进 王友平 向长 《Agricultural Science & Technology》 CAS 2015年第12期2699-2702,共4页
Slow/controlled release fertilizers (SRFs/CRFs) have been paid more at- tentions by the researchersin recent years. In this paper, the application effects and methods, types, current problem and development prospect... Slow/controlled release fertilizers (SRFs/CRFs) have been paid more at- tentions by the researchersin recent years. In this paper, the application effects and methods, types, current problem and development prospect of SRFs/CRFsboth at home and abroad were reviewed. The production principles and processes of urea- formaldehyde slow release fertilizers were introduced; and It is suggested that the urea-formaldehyde slow release fertilizers show great development to ease energy and environment pressure. 展开更多
关键词 slow release fertilizers Urea-formaldehyde slow release fertilizer Appli- cation prospect
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Application Effect of Water-absorbent Slow Release Nitrogen Fertilizer in Latosol
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作者 华元刚 王龙宇 +2 位作者 刘海林 茶正早 林钊沐 《Agricultural Science & Technology》 CAS 2016年第3期603-608,共6页
[Objective] A new-type water-absorbent slow release nitrogen fertilizer(WASRNF) was produced through polymerization reaction. Its physicochemical property and application effect in latosol were studied. Feasibility ... [Objective] A new-type water-absorbent slow release nitrogen fertilizer(WASRNF) was produced through polymerization reaction. Its physicochemical property and application effect in latosol were studied. Feasibility of using WASRNF to improve the serious problems of latosol in rubber planting area in Hainan Island including vulnerable nutrient, free-running fertilizer and water was studied. [Result] The results showed that raw materials of WASRNF, urea and water-retention material formed co-polymer through hydrogen-bond interaction that the WASRNF contained many hydrophilic groups. The p H value of WASRNF is near neutral and its water absorbent rate in tap water could reach 167.17 g·g-1. The water absorbent rates in latosol leach liquors with water/soil ratios of 1:5, 1:10 and 1:20 were 104.66, 122.93 and 145.38 g·g^-1, respectively. The maximum water holding ratio of latosol increased by 23.72%, 30.89% and 39.68% when 0.5%, 1% and 2% WASRNFs were added to latosol, and water evaporation rate of latosol decreased efficiently. Compared with common urea, WASRNF could slow down the leaching rate of nitrogen and the initial leaching amount was only 22.17% of the total amount. [Conclusion]The results indicated that WASRNF in latosol had strong water absorption and water-retention abilities in addition to the good slow release effect, and could efficiently decrease nutrient loss, increase utilization ratio of water and fertilizer and promote interaction between water and fertilizer. 展开更多
关键词 LATOSOL Water-absorbent slow release nitrogen fertilizer(WASRNF) Water-retention slow release
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Effect of Slow and Controlled Release Fertilizers on the Yield and Nutrient Use Efficiency of Hot Pepper in Qiu-bei 被引量:8
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作者 杜彩艳 段宗颜 +2 位作者 鲁耀 胡万里 陈拾华 《Agricultural Science & Technology》 CAS 2011年第5期761-764,共4页
[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers(SCRF)on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei ho... [Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers(SCRF)on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper(Capsicum frutescens L.)as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection. 展开更多
关键词 slow and controlled release fertilizer Qiubei hot pepper YIELD Nutrient use efficiency
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Effects of Slow Release Fertilizer on the Yield and Nutrient Use Efficiency of Carnation and Its Environmental Protection Effect 被引量:4
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作者 杜彩艳 段宗颜 +1 位作者 胡万里 陈拾华 《Agricultural Science & Technology》 CAS 2011年第4期571-575,共5页
[Objective] The aim was to study the effects of slow release fertilizer on the yield,economic benefit and nutrient use efficiency of carnation and environmental pollution.[Method] Taking carnation(Dianthus caryophyl... [Objective] The aim was to study the effects of slow release fertilizer on the yield,economic benefit and nutrient use efficiency of carnation and environmental pollution.[Method] Taking carnation(Dianthus caryophyllus)as research object,the application effect and environmental protection effect of slow release fertilizer on carnation were discussed through field plot test.[Result] The main agronomic characters of carnation improved after the application of slow release fertilizer;compared with Conv-F treatment,the yield of carnation with slow release fertilizer increased by 18.67%-20.83%,and its economic benefit increased by 105 500 yuan/hm2,while the ratio of output to input improved by 74.29%;under the same NPK ratio and nutrient amount,the yield,economic benefit and ratio of output to input of carnation after the application of slow release fertilizer increased by 2.11%,14 800 yuan and 16.2%,respectively;besides,the application of slow release fertilizer improved the nutrient use efficiency of carnation,and N,P and K nutrient use efficiency in Opt-F-0.7% treatment increased by 13.88%,8.57% and 30.14% compared with Conv-F treatment.[Conclusion] Slow release fertilizer could not only reduce the waste of fertilizer resources and improve fertilizer use efficiency but also decrease the pollution caused by nutrient loss,which had important practical significance for protecting ecological environment and promoting the sustainable development of agriculture. 展开更多
关键词 slow release fertilizer CARNATION YIELD Nutrient use efficiency Environmental protection effect
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Vacuum assisted high-pressure die casting of AZ91D magnesium alloy at different slow shot speeds 被引量:8
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作者 王青亮 熊守美 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第10期3051-3059,共9页
The effects of vacuum assistance on the microstructure and mechanical properties of high-pressure die cast AZ91 D alloy at different slow shot speeds were evaluated. Plate-shaped castings of AZ91 D alloy were carried ... The effects of vacuum assistance on the microstructure and mechanical properties of high-pressure die cast AZ91 D alloy at different slow shot speeds were evaluated. Plate-shaped castings of AZ91 D alloy were carried out on a TOYO BD-350V5 cold chamber die casting machine incorporated with a self-improved TOYO vacuum system. It was found that the vacuum pressure in the die cavity at the beginning of mold filling increases with the increase of slow shot speed, following a cubic polynomial curve, resulting in a decline in the porosity-reduction ability of vacuum assistance with the increase of slow shot speed. The externally solidified crystal(ESC) contents in conventional and vacuum die castings behave similar against the slow shot speed. The tensile properties of vacuum die castings were strongly influenced by the ESC content at relative low slow shot speeds. With the increase of slow shot speed, the influence of the gas porosity level in vacuum die castings would get prominent. 展开更多
关键词 vacuum die casting slow shot speed POROSITY externally solidified crystals
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Effect of multi-step slow shot speed on microstructure of vacuum die cast AZ91D magnesium alloy 被引量:3
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作者 王青亮 熊守美 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第2期375-380,共6页
Two multi-step (two-step and three-step) slow shot speeds were used in the vacuum die casting process of AZ91D magnesium alloy. The vacuum pressure variation in the die cavity before mold filling was monitored by us... Two multi-step (two-step and three-step) slow shot speeds were used in the vacuum die casting process of AZ91D magnesium alloy. The vacuum pressure variation in the die cavity before mold filling was monitored by using a pressure sensor. The microstructures of the produced castings were analyzed with optical microscope and image analysis software. The experimental results demonstrate that, the vacuum pressure in the die cavity at the beginning of mold filling is significantly reduced by using three-step slow shot speed, resulting in a low gas porosity level in the produced castings. At an appropriate multi-step slow shot speed, the dwell time of the liquid metal in the shot sleeve before mold filling can be reduced and the flow of the liquid metal in the shot sleeve at the later stage of the slow shot process can be restrained, which cause a low externally solidified crystal content in the produced castings. 展开更多
关键词 magnesium alloy vacuum die casting slow shot speed gas porosity externally solidified crystal
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Thickness Impacts of Vacancy Defects in Epitaxial La0.7Sr0.3MnO3 Thin Films Using Slow Positron Beam 被引量:1
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作者 刘建党 成斌 +1 位作者 杜淮江 叶邦角 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第6期685-688,746,共5页
Thickness effects of thin La0.7Sr0.3MnO3 (LSMO) films on (LaAlOa)0.3(Sr2AlTaO6)0.7 substrates were examined by a slow positron beam technique. Doppler-broadening line shape parameter S was measured as a function... Thickness effects of thin La0.7Sr0.3MnO3 (LSMO) films on (LaAlOa)0.3(Sr2AlTaO6)0.7 substrates were examined by a slow positron beam technique. Doppler-broadening line shape parameter S was measured as a function of thickness and differnt annealing conditions. Results reveal there could be more than one mechanism to induce vacancy-like defects. It was found that strain-induced defects mainly influence the S value of the in situ oxygenambience annealing LSMO thin films and the strain could vanish still faster along with the increase of thickness, and the oxygen-deficient induced defects mainly affect the S value of post-annealing LSMO films. 展开更多
关键词 Thin film Giant magnetoresistance slow positron beam DEFECT
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Effects of Calcium Element on Biomass and Effective Constituents Contents in Blumea balsamifera in Slow Growth Period of Winter 被引量:1
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作者 王丹 马青松 +4 位作者 范佐旺 李小婷 宛骏 陈振夏 庞玉新 《Agricultural Science & Technology》 CAS 2016年第2期358-361,437,共5页
The one-year-old seedlings of Blumea balsamifera (L.) DC. were applied with CaCl2.H2O that supplied Ca in slow growth period of winter three times. The heights, ground diameters, leaf lengths, leaf widths and biomas... The one-year-old seedlings of Blumea balsamifera (L.) DC. were applied with CaCl2.H2O that supplied Ca in slow growth period of winter three times. The heights, ground diameters, leaf lengths, leaf widths and biomasses of B. balsamifera plants were measured. In addition, the relative contents of total flavones in different parts of B. balsamifera were determined by UV spectrophotometry, and the absolute contents of total flavones were calculated. The relative contents of L-borneol in leaves of B. balsamifera were determined by GC, and the absolute contents of L- borneol were calculated. The results showed that calcium element significantly in- creased the biomasses in leaves, stems and roots of B. balsamifera in slow growth period of winter. The leaf biomass of B. balsamifera in the 5 g/L CaCl2-H2O treat- ment group was significantly higher than those in the other three treatment groups. The leaf biomasses of B. balsamifera in the 10 and 15 g/L CaCl2.H2O treatment groups were significantly higher than that in the CK, with 3.03 and 2.65 times, re- spectively. The application of Ca inhibited the accumulation of total flavones relative contents, but significantly increased the total flavones absolute contents in different parts of B. balsamifera. The relative and absolute contents of L-borneol in the 5 g/L CaCl2 .H2O treatment group were 0.22% and 0.22 g, which were increased by 37.50%, 22.22%, 37.50% and 100%, 100%, 450%, respectively compared with those in the 0, 10 and 15 g/L CaCl2.H2O treatment groups. The Ca element could signifi- cantly promote the accumulation of biomasses in leaves, stems and roots, as well as the absolute contents of total flavones and L-borneol in B. balsamifera in slow growth period of winter. 展开更多
关键词 Calcium (Ca) Blumea balsamifera slow growth period L-borneol Total flavones: Biomass
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Numerical Explanation of Slow Transients in an AlGaN/GaN HEMT
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作者 张金风 郝跃 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第2期276-282,共7页
A series of slow drain current recovery transients at different gate biases after a short-term stress are observed in an AIGaN/GaN HEMT. As the variation of the time constants of the transients is small, the working t... A series of slow drain current recovery transients at different gate biases after a short-term stress are observed in an AIGaN/GaN HEMT. As the variation of the time constants of the transients is small, the working trap is determined to be electronic. A numerical simulation verifies this conclusion and reproduces the measured transients. The electron traps at different spatial positions in the device-on the ungated surface of the AIGaN layer,in the AIGaN barrier, and in the GaN layer are considered;corresponding behaviors in the stress and the transients are discussed;and for the simulated transients, agreement with and deviation from the measured transients are explained. Based on this discussion, we suggest that the measured transients are caused by the combined effects of a deep surface trap and a bulk trap in the GaN layer. 展开更多
关键词 AIGaN/GaN HEMT slow transients virtual gate surface trap bulk trap
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基于改进Slow-Only网络的骨骼点动作识别方法研究 被引量:1
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作者 田青 冯赛楠 +3 位作者 魏运 豆飞 赵志强 张超 《工业控制计算机》 2023年第7期54-57,共4页
由于存在人体之间相互遮挡、受环境变化影响较大、时序特征提取能力较弱等问题,现有的动作识别方法在精准度方面仍有不足,因此,提出了一种基于改进Slow-Only网络的骨骼点动作识别方法。首先,将骨骼关键点数据进行预处理,分别在时间和空... 由于存在人体之间相互遮挡、受环境变化影响较大、时序特征提取能力较弱等问题,现有的动作识别方法在精准度方面仍有不足,因此,提出了一种基于改进Slow-Only网络的骨骼点动作识别方法。首先,将骨骼关键点数据进行预处理,分别在时间和空间维度减少冗余信息;其次,基于Slow-Only网络,重新设计了时间卷积模块,以更好地提取视频帧所包含的时序信息;最后,增加了改进的注意力机制模块,以降低遮挡问题带来的影响。在NTU RGB+D数据集上进行了实验,实验结果表明该方法能有效地提升检测精度,并且在实际场景中具有应用价值。 展开更多
关键词 骨骼关键点 slow-Only网络 动作识别 时序特征 通道注意力
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