Although time-dependent deformation of geomaterials underpins slope-failure prediction models,the influence of strain rate on shearing strength and deformation behavior of loess remains unclear.The consolidated undrai...Although time-dependent deformation of geomaterials underpins slope-failure prediction models,the influence of strain rate on shearing strength and deformation behavior of loess remains unclear.The consolidated undrained(CU)and drained(CD)triaxial testing elucidated the impact of strain rate(0.005–0.3 mm/min)on strength envelopes,deformation moduli,pore pressures,and dilatancy characteristics of unsaturated and quasi-saturated loess.Under drained conditions with a controlled matric suction of 50 kPa,increasing strain rates from 0.005 mm/min to 0.011 mm/min induced decreases in failure deviatoric stress(qf),initial deformation modulus(Ei),and cohesion(c),while friction angles remained unaffected.Specimens displayed initial contractive volumetric strains transitioning to dilation across varying confining pressures.Higher rates diminished contractive volumetric strains and drainage volumes,indicating reduced densification and strength in the shear zone.Under undrained conditions,both unsaturated and quasi-saturated(pore pressure coefficient B=0.75)loess exhibited deteriorating mechanical properties with increasing rates from 0.03 mm/min to 0.3 mm/min.For unsaturated loess,reduced contractive volumetric strains at higher rates manifested relatively looser structures in the pre-peak stress phase.The strength decrement in quasi-saturated loess arose from elevated excess porewater pressures diminishing effective stresses.Negative porewater pressures emerged in quasi-saturated loess at lower confining pressures and strain rates.Compared to previous studies,the qf and Ei exhibited rate sensitivity below threshold values before attaining minima with marginal subsequent influence.The underlying mechanism mirrors the transition from creep to accelerated deformation phase of landslides.展开更多
BACKGROUND Sessile serrated lesions(SSLs)are premalignant polyps implicated in up to 30%of colorectal cancers.Australia reports high SSL detection rates(SSL-DRs),yet with marked variability(3.1%-24%).This substantial ...BACKGROUND Sessile serrated lesions(SSLs)are premalignant polyps implicated in up to 30%of colorectal cancers.Australia reports high SSL detection rates(SSL-DRs),yet with marked variability(3.1%-24%).This substantial variation raises concerns about missed lesions and post-colonoscopy colorectal cancer.This study investigates determinants associated with SSL-DR variation in regional Australia.AIM To study how patient,clinical,and colonoscopy factors are associated with SSL detection in a regional Australian practice.We aimed to contribute high-detection data to the literature by analyzing the association of SSL detection with various determinants.METHODS This retrospective,cross-sectional analysis examined 1450 colonoscopies performed at Port Macquarie Gastroenterology during 2023.Sigmoidoscopies and repeat procedures were excluded.Multivariate logistic regression analyzed associations between SSL detection and patient demographics,clinical indications,procedural factors,and comorbidities.RESULTS The overall SSL-DR was 30.7%.Multivariate analysis identified several independent predictors:Clinical indication,bowel preparation quality,inflammatory bowel disease status,and serrated polyposis syndrome.The faecal occult blood test positive(FOBT)(+)cohort showed the highest predicted SSL detection probability(39.8%),while clinical symptoms showed the lowest(22.3%).After adjustment,SSL detection odds were 2.3 times greater among FOBT(+)patients than those with clinical symptoms(adjusted odds ratio=2.30,95%confidence interval:1.20-4.40,P=0.004).CONCLUSION SSL-DR as a quality indicator requires contextualization regarding clinical indications,bowel preparation quality,and comorbidities.There was a significantly higher prevalence of SSLs in FOBT(+)patients.Despite comprehensive adjustment,this study cannot fully explain the wide SSL-DR variation in Australia,highlighting the need for standardized detection protocols and further research to ensure optimal cancer prevention outcomes.展开更多
Under the“dual carbon”goals,this paper constructs an optimization model of the comprehensive energy system in the park.A stepwise carbon excess rate mechanism and an electric vehicle coupling strategy are proposed:A...Under the“dual carbon”goals,this paper constructs an optimization model of the comprehensive energy system in the park.A stepwise carbon excess rate mechanism and an electric vehicle coupling strategy are proposed:A carbon quota trading system is established based on the baseline method,and the stepwise function is adopted to quantify the cost of excess carbon emissions;Introduce the price demand response and the two-way interaction mechanism of electric Vehicle vehicle-to-grid(V2G)to enhance the flexible regulation ability.Aiming at the uncertainty of wind and solar output,a typical scene set is generated by combining Latin hypercube sampling with the scene reduction method.The goal is to minimize the operating cost and maximize the consumption of renewable energy,and it is solved through the CPLEX solver in the MATLAB platform.Through simulation verification of the proposed models and methods in various scenarios,the simulation results show that under the coupling of the carbon excess rate trading mechanism,the demand response mechanism,and the vehicle-to-grid interaction of electric vehicles,the total daily operating cost of the system decreases by 25.3%,reduce the dual pressure of energy consumption costs and the economic environment,and achieve the coordinated optimization of economic and ecological benefits.展开更多
Unsaturated alcohols are a class of Biogenic volatile organic compounds(BVOCs)emitted in large quantities by plants when damaged or under adverse environmental conditions,and studies on their atmospheric degradation a...Unsaturated alcohols are a class of Biogenic volatile organic compounds(BVOCs)emitted in large quantities by plants when damaged or under adverse environmental conditions,and studies on their atmospheric degradation at night are still lacking.We used chamber experiments to study the gas-phase reactions of three unsaturated alcohols,E-2-penten-1-ol,Z-2-hexen-1-ol and Z-3-hepten-1-ol,with NO_(3)radicals(NO_(3)•)during the night.The rate constants of these reactions were(11.7±1.76)×10^(−13),(8.55±1.33)×10^(−13)and(6.08±0.47)×10^(−13)cm^(3)/(molecule·s)at 298K and 760 Torr,respectively.In contrast,the reaction rate of similar substances with ozone was about 10^(−18)cm^(3)/(molecule·s),which indicates that the reaction with NO_(3)•is themain oxidation pathway for unsaturated alcohols at night.Small molecule aldehydes and ketones were the main gas-phase organic products of the reaction of three aldehydes and ketones with NO_(3)•,and the total small molecule aldehydes and ketones yields can reach between 45%-60%.They mainly originate from the breakage of alkoxy radicals,and different breakage sites determine different product distributions.In addition,the SOA yields of the three unsaturated alcohols with NO_(3)•were 7.1%±1.0%,12.5%±1.9%and 30.0%±4.5%,respectively,whichweremuch higher than those of similarly structured substances with O_(3)or OH radicals(•OH).The results of high-resolution mass spectrometry shows that the main components of Secondary organic aerosol(SOA)of the three unsaturated alcohols are dimeric compounds containing several nitrate groups,which are formed through the polymerization of oxyalkyl radicals.展开更多
This study presents an in-depth investigation into the shear strength characteristics of unsaturated soils,focusing on the influenceof shear rate and initial water saturation(S_(r0)).Utilizing the drained-vented(DV)tr...This study presents an in-depth investigation into the shear strength characteristics of unsaturated soils,focusing on the influenceof shear rate and initial water saturation(S_(r0)).Utilizing the drained-vented(DV)triaxial test method,the present study investigated the shear strength behavior of silty clay under various shear rates and water saturation levels,and compared the outcomes with traditional suction-controlled(SC)and constant water content(CW)tests.The findingshighlight the pivotal role of excess pore water pressure dissipation during shearing,which significantlyaffects the shear strength of both saturated and unsaturated soils.Notably,for soils with high initial water saturation,a decrease in shear strength is observed with an increase in shear rate,which is attributed to the rise in pore water pressure.Conversely,for soils with low initial water saturation,the shear rate exhibits minimal impact on shear strength due to negligible water drainage.The research delineates the optimal shear rates for DV tests based on the initial water saturation:a slower rate of 0.0028 mm/min for samples with high water saturation(S_(r0)>66%)and a faster rate of 0.8 mm/min for samples with low water saturation(S_(r0)≤66%).A novel testing methodology for determining unsaturated soil shear strength under DV conditions is introduced,streamlining the measurement process and significantly reducing testing time.This method not only promises substantial cost savings but also aligns closely with natural engineering conditions,offering valuable guidance for geotechnical applications.展开更多
In the gas-coal integrated mining field,the conventional design method of pipeline coal pillars leads to a large amount of coal pillars being unrecovered and overlooks the pipeline's safety requirements.Considerin...In the gas-coal integrated mining field,the conventional design method of pipeline coal pillars leads to a large amount of coal pillars being unrecovered and overlooks the pipeline's safety requirements.Considering the coal pillar recovery rate and pipeline's safety requirements,two new shaped coal pillar design approaches for subsurface pipelines were developed.Firstly,the deformation limitations for measuring pipeline safety are categorized into two:no deformation is permitted,and deformation is acceptable within elastic limits.Subsequently,integrating the key stratum theory(KST)and cave angle,a fishbone-shaped coal pillar design approach that does not permit pipeline deformation is established.Meanwhile,combined with the ground subsidence and the pipeline's elastic deformation limit,a grille-shaped coal pillar design approach that accepts deformation pipelines within elastic limits is established.Those two new approaches clarify parameters including mined width,coal pillar width and mined length.Finally,the case study shows that the designed mined width,coal pillar width and mined length of the fishbone-shaped coal pillar are 90,80,and 130 m,while those of the grille-shaped are 320,370,and640 m.Compared with the conventional method,the fishbone-shaped and grille-shaped coal pillar design approaches recovered coal pillar resources of 2.65×10~6and 5.81×10~6t on the premise of meeting the pipeline safety requirements,and the recovery rates increased by 20.5%and 45.0%,with expenditures representing only 56.46%and 20.02%of the respective benefits.These new approaches provide managers with diverse options for protecting pipeline safety while promoting coal pillar recovery,which is conducive to the harmonic mining of gas-coal resources.展开更多
Nitrogen oxides(NO_(x))and particulate matter(PM)present significant risks to both human health and environmental sustainability.The Integrated Dust Removal and Denitrification Technology(DRDt)offers a more efficient ...Nitrogen oxides(NO_(x))and particulate matter(PM)present significant risks to both human health and environmental sustainability.The Integrated Dust Removal and Denitrification Technology(DRDt)offers a more efficient and cost-effective solution for achieving ultralow industrial flue gas emissions;however,its effectiveness is undermined by low catalyst load rates and poor stability in filter materials.This study addresses these limitations by modifying conventional PTFE filter media(PTFE-Tim)through the incorporation of sodium alginate(SA)and dopamine(DA)as modifiers,resulting in two new filter materials:PTFE-SA-MOF and PTFE-DA-MOF.By optimizing the parameters of an orthogonal experimental design,we identified the ideal preparation conditions for these composite materials.The addition of SA and DA enhanced the bonding between the catalyst(Mn-Cu-MOF)crystal particles and the PTFE fibers through mechanisms such as ion exchange,hydrogen bonding,and adhesion.Consequently,the catalyst loading rate and stability of the DRDt filters were significantly improved.Specifically,the PTFE-SA-MOF and PTFE-DA-MOF filters achieved high catalyst loading rates of 15.97% and 15.86%,these values represent improvements of 2.53 and 2.51 times,while maintaining excellent stability,with mass retention rates of 98.64% and 98.27%,respectively,over the conventional PTFE-Tim filter.展开更多
Injection rate is crucial for determining the hydraulic fracturing effectiveness;however,the effects of the injection rate on the pore and fracture structure(PFS)and fluid infiltration during injection pressurization ...Injection rate is crucial for determining the hydraulic fracturing effectiveness;however,the effects of the injection rate on the pore and fracture structure(PFS)and fluid infiltration during injection pressurization have rarely been explored.In this study,the cylindrical sandstone samples were hydraulically fractured at various injection rates on a self-developed integrated nuclear magnetic resonance(NMR)and hydraulic fracturing experimental system.The results show that low injection rates predominantly resulted in macropore-scale damage by creating intergranular cracks,whereas high injection rates facilitated micropore-scale damage,probably owing to the adsorption swelling effect of clay minerals within pores.Additionally,the water contents of the samples with low injection rates exhibited a continuous increase,whereas those of the samples with high injection rates initially increased and subsequently stabilized.Magnetic resonance imaging(MRI)indicated that fluid infiltration during the fracturing process exhibited high anisotropy owing to the inherent heterogeneous PFS distributions around the wellbore.Moreover,a primary fluid infiltration path exists that aligns with the initiation direction of the hydraulic fractures.However,the fluid infiltration damage distance along the hydraulic fracture direction decreased with increasing injection rate,whereas the fluid infiltration damage distance perpendicular to the hydraulic fracture direction was approximately equal to the characteristic length,regardless of the injection rate.Finally,we recommend using the pore damage during fluid pressurization as the basis for selecting the proppant size and employing a primary fluid infiltration path to predict hydraulic fracture initiation.These findings provide valuable insights into the design of hydraulic fracturing in tight gas reservoirs.展开更多
In the assessment of car insurance claims,the claim rate for car insurance presents a highly skewed probability distribution,which is typically modeled using Tweedie distribution.The traditional approach to obtaining ...In the assessment of car insurance claims,the claim rate for car insurance presents a highly skewed probability distribution,which is typically modeled using Tweedie distribution.The traditional approach to obtaining the Tweedie regression model involves training on a centralized dataset,when the data is provided by multiple parties,training a privacy-preserving Tweedie regression model without exchanging raw data becomes a challenge.To address this issue,this study introduces a novel vertical federated learning-based Tweedie regression algorithm for multi-party auto insurance rate setting in data silos.The algorithm can keep sensitive data locally and uses privacy-preserving techniques to achieve intersection operations between the two parties holding the data.After determining which entities are shared,the participants train the model locally using the shared entity data to obtain the local generalized linear model intermediate parameters.The homomorphic encryption algorithms are introduced to interact with and update the model intermediate parameters to collaboratively complete the joint training of the car insurance rate-setting model.Performance tests on two publicly available datasets show that the proposed federated Tweedie regression algorithm can effectively generate Tweedie regression models that leverage the value of data fromboth partieswithout exchanging data.The assessment results of the scheme approach those of the Tweedie regressionmodel learned fromcentralized data,and outperformthe Tweedie regressionmodel learned independently by a single party.展开更多
Federated Learning(FL)is an emerging machine learning framework designed to preserve privacy.However,the continuous updating of model parameters over uplink channels with limited throughput leads to a huge communicati...Federated Learning(FL)is an emerging machine learning framework designed to preserve privacy.However,the continuous updating of model parameters over uplink channels with limited throughput leads to a huge communication overload,which is a major challenge for FL.To address this issue,we propose an adaptive gradient quantization approach that enhances communication efficiency.Aiming to minimize the total communication costs,we consider both the correlation of gradients between local clients and the correlation of gradients between communication rounds,namely,in the time and space dimensions.The compression strategy is based on rate distortion theory,which allows us to find an optimal quantization strategy for the gradients.To further reduce the computational complexity,we introduce the Kalman filter into the proposed approach.Finally,numerical results demonstrate the effectiveness and robustness of the proposed rate-distortion optimization adaptive gradient quantization approach in significantly reducing the communication costs when compared to other quantization methods.展开更多
This work aimed to construct an epidemic model with fuzzy parameters.Since the classical epidemic model doesnot elaborate on the successful interaction of susceptible and infective people,the constructed fuzzy epidemi...This work aimed to construct an epidemic model with fuzzy parameters.Since the classical epidemic model doesnot elaborate on the successful interaction of susceptible and infective people,the constructed fuzzy epidemicmodel discusses the more detailed versions of the interactions between infective and susceptible people.Thenext-generation matrix approach is employed to find the reproduction number of a deterministic model.Thesensitivity analysis and local stability analysis of the systemare also provided.For solving the fuzzy epidemic model,a numerical scheme is constructed which consists of three time levels.The numerical scheme has an advantage overthe existing forward Euler scheme for determining the conditions of getting the positive solution.The establishedscheme also has an advantage over existing non-standard finite difference methods in terms of order of accuracy.The stability of the scheme for the considered fuzzy model is also provided.From the plotted results,it can beobserved that susceptible people decay by rising interaction parameters.展开更多
The strength of rock materials is largely affected by water and loading conditions, but there are few studies on mechanical properties of saturated rocks at high strain rates. Through compressive tests on dry and satu...The strength of rock materials is largely affected by water and loading conditions, but there are few studies on mechanical properties of saturated rocks at high strain rates. Through compressive tests on dry and saturated sandstone specimens, it was found that the dynamic compressive strength of both dry and saturated sandstone specimens increased with the increase of strain rates. The saturated rock specimens showed stronger rate dependence than the dry ones. The water affecting factor （WAF）, as the ratio of the strength under dry state to that under saturated state, was introduced to describe the influence of water on the compressive strength at different strain rates. The WAF under static load was close to 1.38, and decreased with the increase of strain rate. When the strain rate reached 190 s^-1, the WAF reduced to 0.98. It indicates that the compressive strength of saturated specimens can be higher than that of dry ones when the strain rate is high enough. Furthermore, the dual effects of water and strain rate on the strength of rock were discussed based on sliding crack model, which provided a good explanation for the experimental results.展开更多
Purpose:The notable increase in retraction papers has attracted considerable attention from diverse stakeholders.Various sources are now offering information related to research integrity,including concerns voiced on ...Purpose:The notable increase in retraction papers has attracted considerable attention from diverse stakeholders.Various sources are now offering information related to research integrity,including concerns voiced on social media,disclosed lists of paper mills,and retraction notices accessible through journal websites.However,despite the availability of such resources,there remains a lack of a unified platform to consolidate this information,thereby hindering efficient searching and cross-referencing.Thus,it is imperative to develop a comprehensive platform for retracted papers and related concerns.This article aims to introduce“Amend,”a platform designed to integrate information on research integrity from diverse sources.Design/methodology/approach:The Amend platform consolidates concerns and lists of problematic articles sourced from social media platforms(e.g.,PubPeer,For Better Science),retraction notices from journal websites,and citation databases(e.g.,Web of Science,CrossRef).Moreover,Amend includes investigation and punishment announcements released by administrative agencies(e.g.,NSFC,MOE,MOST,CAS).Each related paper is marked and can be traced back to its information source via a provided link.Furthermore,the Amend database incorporates various attributes of retracted articles,including citation topics,funding details,open access status,and more.The reasons for retraction are identified and classified as either academic misconduct or honest errors,with detailed subcategories provided for further clarity.Findings:Within the Amend platform,a total of 32,515 retracted papers indexed in SCI,SSCI,and ESCI between 1980 and 2023 were identified.Of these,26,620(81.87%)were associated with academic misconduct.The retraction rate stands at 6.64 per 10,000 articles.Notably,the retraction rate for non-gold open access articles significantly differs from that for gold open access articles,with this disparity progressively widening over the years.Furthermore,the reasons for retractions have shifted from traditional individual behaviors like falsification,fabrication,plagiarism,and duplication to more organized large-scale fraudulent practices,including Paper Mills,Fake Peer-review,and Artificial Intelligence Generated Content(AIGC).Research limitations:The Amend platform may not fully capture all retracted and concerning papers,thereby impacting its comprehensiveness.Additionally,inaccuracies in retraction notices may lead to errors in tagged reasons.Practical implications:Amend provides an integrated platform for stakeholders to enhance monitoring,analysis,and research on academic misconduct issues.Ultimately,the Amend database can contribute to upholding scientific integrity.Originality/value:This study introduces a globally integrated platform for retracted and concerning papers,along with a preliminary analysis of the evolutionary trends in retracted papers.展开更多
Orbital-angular-momentum(OAM)multiplexing technology offers a significant dimension to enlarge communication capacity in free-space optical links.The coherent beam combining(CBC)system can simultaneously realize OAM m...Orbital-angular-momentum(OAM)multiplexing technology offers a significant dimension to enlarge communication capacity in free-space optical links.The coherent beam combining(CBC)system can simultaneously realize OAM multiplexing and achieve high-power laser output,providing substantial advantages for long-distance communication.Herein,we present an integrated CBC system for freespace optical links based on OAM multiplexing and demultiplexing technologies for the first time,to the best of our knowledge.A method to achieve flexible OAM multiplexing and efficient demultiplexing based on the CBC system is proposed and demonstrated both theoretically and experimentally.The experimental results exhibit a low bit error rate of 0.47%and a high recognition precision of 98.58%throughout the entire data transmission process.By employing such an ingenious strategy,this work holds promising prospects for enriching ultra-long-distance structured light communication in the future.展开更多
Through different dose-rate switching evaluation methods,the radiation-response rules of operational amplifiers are studied when the irradiation dose rate is switched from high to low under different radiation tempera...Through different dose-rate switching evaluation methods,the radiation-response rules of operational amplifiers are studied when the irradiation dose rate is switched from high to low under different radiation temperatures and total doses. The experimental results indicate that the response characteristics could be affected by the switching total doses, irradiation temperatures,and dose rates individually or together. Accelerated evaluation on the ELDRS can be realized by adopting a proper dose-rate switching method. Meanwhile, the irradiation time can also be reduced. Finally, the mechanisms of the difference between various radiation responses are analyzed.展开更多
Synthesis of the spinel structure lithium manganese oxide （LiMn2O4） by supercritical hydrothermal （SH） accelerated solid state reaction （SSR） route was studied. The impacts of the reaction pressure, reaction tem...Synthesis of the spinel structure lithium manganese oxide （LiMn2O4） by supercritical hydrothermal （SH） accelerated solid state reaction （SSR） route was studied. The impacts of the reaction pressure, reaction temperature and reaction time of SH route, and the calcination temperature of SSR route on the purity, particle morphology and electrochemical properties of the prepared LiMn2O4 materials were studied. The experimental results show that after 15 min reaction in SH route at 400 ℃ and 30 MPa, the reaction time of SSR could be significantly decreased, e.g. down to 3 h with the formation temperature of 800 ℃, compared with the conventional solid state reaction method. The prepared LiMn2O4 material exhibits good crystallinity, uniform size distribution and good electrochemical performance, and has an initial specific capacity of 120 mA.h/g at a rate of 0.1C （1C=148 mA/g） and a good rate capability at high rates, even up to 50C.展开更多
Reconfigurable intelligent surface(RIS)has been proposed as a potential solution to improve the coverage and spectrum efficiency for future wireless communication.However,the privacy of users’data is often ignored in...Reconfigurable intelligent surface(RIS)has been proposed as a potential solution to improve the coverage and spectrum efficiency for future wireless communication.However,the privacy of users’data is often ignored in previous works,such as the user’s location information during channel estimation.In this paper,we propose a privacy-preserving design paradigm combining federated learning(FL)with RIS in the mmWave communication system.Based on FL,the local models are trained and encrypted using the private data managed on each local device.Following this,a global model is generated by aggregating them at the central server.The optimal model is trained for establishing the mapping function between channel state information(CSI)and RIS’configuration matrix in order to maximize the achievable rate of the received signal.Simulation results demonstrate that the proposed scheme can effectively approach to the theoretical value generated by centralized machine learning(ML),while protecting user’privacy.展开更多
AIM:To evaluate the effectiveness of omega-3 polyunsaturated fatty acid(ω-3 PUFA) administration on liver regeneration after 90% partial hepatectomy(PH) in rats.METHODS:ω-3 PUFAs were intravenously injected in the ...AIM:To evaluate the effectiveness of omega-3 polyunsaturated fatty acid(ω-3 PUFA) administration on liver regeneration after 90% partial hepatectomy(PH) in rats.METHODS:ω-3 PUFAs were intravenously injected in the ω-3 PUFA group before PH surgery.PH,sparing only the caudate lobe,was performed in both the control and the ω-3 PUFA group.Survival rates,liver weight/body weight ratios,liver weights,HE staining,transmission electron microscope imaging,nuclearassociated antigen Ki-67,enzyme-linked immunosorbent assay and signal transduction were evaluated to analyze liver regeneration.RESULTS:All rats in the control group died within 30 h after hepatectomy.Survival rates in the ω-3 PUFA group were 20/20 at 30 h and 4/20 1 wk after PH.Liver weight/body weight ratios and liver weights increased significantly in the ω-3 PUFA group.The structure of sinusoidal endothelial cells and space of Disse was greatly restored in the ω-3 PUFA group compared to the control group after PH.In the ω-3 PUFA group,interleukin(IL)-4 and IL-10 levels were significantly increased whereas IL-6 and tumor necrosis factor-levels were dramatically decreased.In addition,activation of protein kinase B(Akt) and of signal transducer and activator of transcription 3 signaling pathway were identified at an earlier time after PH in the ω-3 PUFA group.CONCLUSION:Omega-3 polyunsaturated fatty acids may prevent acute liver failure and promote liver regeneration after 90% hepatectomy in rats.展开更多
In order to analyze the impact of stretching-segment on the saturated flow rate of signalized intersection approach, an improved cellular automation model was proposed to estimate its saturated flow rate. The NaSch mo...In order to analyze the impact of stretching-segment on the saturated flow rate of signalized intersection approach, an improved cellular automation model was proposed to estimate its saturated flow rate. The NaSch model was improved by adding different slow probabilities, turning deceleration rules and modified lane changing rules. The relationship between the saturated flow rate of stretching-segments and adjacent lanes was tested in numerical simulation. The length of stretching-segment, cycle length and green time were selected as impact factors of the cellular automation model. The simulation result indicates that the geometrics design of stretching-segment and the traffic signal timing scenario have major effects on the saturated flow rate of the intersection approach. The saturated flow rate will continually increase with increasing stretching-segment length until it reaches a threshold. After reaching the threshold, the stretching-segment can be treated as a separate lane. The green time is approximately linearly related to the threshold length of the stretching-segment. An optimum cycle length exists when the length of the stretching-segment is not long enough, and it is approximately linearly related to the length of stretching-segment.展开更多
Rate constants for the reactions of ozone with 1-octen-3-ol, 1-nonen-3-ol and 1-nonen-4-ol have been determined at 298 ±1 K and atmospheric pressure for the first time. The experiments were performed in a 100-L F...Rate constants for the reactions of ozone with 1-octen-3-ol, 1-nonen-3-ol and 1-nonen-4-ol have been determined at 298 ±1 K and atmospheric pressure for the first time. The experiments were performed in a 100-L FEP Teflon film bag using absolute rate method; the rate constants were （1.91 ± 0.19） ×10^-17, （1.89 ± 0.20） × 10^-17, and （0.83 ± 0.08） × 10^-17 cm^3/（molecule.sec） for 1-octen-3-ol, 1-nonen-3-ol, and 1-nonen-4-ol, respectively. The rate constants have been compared with those of unsaturated alcohols structural homologs, and used to estimate the reaction reactivity. The electronegativity of carbon-carbon double bond was calculated by atomic charges analysis. The calculated results show that the electronic effect of the lone pair electrons of hydroxyl oxygen is the main cause of the difference in rate coefficient. According to the obtained rate constants, the atmospheric lifetimes of studied unsaturated alcohols were also estimated, which indicates that the reaction with ozone is an important loss pathway in the atmosphere, especially in polluted areas.展开更多
文摘Although time-dependent deformation of geomaterials underpins slope-failure prediction models,the influence of strain rate on shearing strength and deformation behavior of loess remains unclear.The consolidated undrained(CU)and drained(CD)triaxial testing elucidated the impact of strain rate(0.005–0.3 mm/min)on strength envelopes,deformation moduli,pore pressures,and dilatancy characteristics of unsaturated and quasi-saturated loess.Under drained conditions with a controlled matric suction of 50 kPa,increasing strain rates from 0.005 mm/min to 0.011 mm/min induced decreases in failure deviatoric stress(qf),initial deformation modulus(Ei),and cohesion(c),while friction angles remained unaffected.Specimens displayed initial contractive volumetric strains transitioning to dilation across varying confining pressures.Higher rates diminished contractive volumetric strains and drainage volumes,indicating reduced densification and strength in the shear zone.Under undrained conditions,both unsaturated and quasi-saturated(pore pressure coefficient B=0.75)loess exhibited deteriorating mechanical properties with increasing rates from 0.03 mm/min to 0.3 mm/min.For unsaturated loess,reduced contractive volumetric strains at higher rates manifested relatively looser structures in the pre-peak stress phase.The strength decrement in quasi-saturated loess arose from elevated excess porewater pressures diminishing effective stresses.Negative porewater pressures emerged in quasi-saturated loess at lower confining pressures and strain rates.Compared to previous studies,the qf and Ei exhibited rate sensitivity below threshold values before attaining minima with marginal subsequent influence.The underlying mechanism mirrors the transition from creep to accelerated deformation phase of landslides.
文摘BACKGROUND Sessile serrated lesions(SSLs)are premalignant polyps implicated in up to 30%of colorectal cancers.Australia reports high SSL detection rates(SSL-DRs),yet with marked variability(3.1%-24%).This substantial variation raises concerns about missed lesions and post-colonoscopy colorectal cancer.This study investigates determinants associated with SSL-DR variation in regional Australia.AIM To study how patient,clinical,and colonoscopy factors are associated with SSL detection in a regional Australian practice.We aimed to contribute high-detection data to the literature by analyzing the association of SSL detection with various determinants.METHODS This retrospective,cross-sectional analysis examined 1450 colonoscopies performed at Port Macquarie Gastroenterology during 2023.Sigmoidoscopies and repeat procedures were excluded.Multivariate logistic regression analyzed associations between SSL detection and patient demographics,clinical indications,procedural factors,and comorbidities.RESULTS The overall SSL-DR was 30.7%.Multivariate analysis identified several independent predictors:Clinical indication,bowel preparation quality,inflammatory bowel disease status,and serrated polyposis syndrome.The faecal occult blood test positive(FOBT)(+)cohort showed the highest predicted SSL detection probability(39.8%),while clinical symptoms showed the lowest(22.3%).After adjustment,SSL detection odds were 2.3 times greater among FOBT(+)patients than those with clinical symptoms(adjusted odds ratio=2.30,95%confidence interval:1.20-4.40,P=0.004).CONCLUSION SSL-DR as a quality indicator requires contextualization regarding clinical indications,bowel preparation quality,and comorbidities.There was a significantly higher prevalence of SSLs in FOBT(+)patients.Despite comprehensive adjustment,this study cannot fully explain the wide SSL-DR variation in Australia,highlighting the need for standardized detection protocols and further research to ensure optimal cancer prevention outcomes.
基金sponsored by National Natural Science Foundation of China(52077137).
文摘Under the“dual carbon”goals,this paper constructs an optimization model of the comprehensive energy system in the park.A stepwise carbon excess rate mechanism and an electric vehicle coupling strategy are proposed:A carbon quota trading system is established based on the baseline method,and the stepwise function is adopted to quantify the cost of excess carbon emissions;Introduce the price demand response and the two-way interaction mechanism of electric Vehicle vehicle-to-grid(V2G)to enhance the flexible regulation ability.Aiming at the uncertainty of wind and solar output,a typical scene set is generated by combining Latin hypercube sampling with the scene reduction method.The goal is to minimize the operating cost and maximize the consumption of renewable energy,and it is solved through the CPLEX solver in the MATLAB platform.Through simulation verification of the proposed models and methods in various scenarios,the simulation results show that under the coupling of the carbon excess rate trading mechanism,the demand response mechanism,and the vehicle-to-grid interaction of electric vehicles,the total daily operating cost of the system decreases by 25.3%,reduce the dual pressure of energy consumption costs and the economic environment,and achieve the coordinated optimization of economic and ecological benefits.
基金supported by the National Key Research and Development Program of China(No.2020YFA0607800)the National Natural Science Foundation of China(Nos.42022039 and 42130606)Beijing National Laboratory for Molecular Sciences(No.BNLMS-CXXM-202011),the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.Y2021013).
文摘Unsaturated alcohols are a class of Biogenic volatile organic compounds(BVOCs)emitted in large quantities by plants when damaged or under adverse environmental conditions,and studies on their atmospheric degradation at night are still lacking.We used chamber experiments to study the gas-phase reactions of three unsaturated alcohols,E-2-penten-1-ol,Z-2-hexen-1-ol and Z-3-hepten-1-ol,with NO_(3)radicals(NO_(3)•)during the night.The rate constants of these reactions were(11.7±1.76)×10^(−13),(8.55±1.33)×10^(−13)and(6.08±0.47)×10^(−13)cm^(3)/(molecule·s)at 298K and 760 Torr,respectively.In contrast,the reaction rate of similar substances with ozone was about 10^(−18)cm^(3)/(molecule·s),which indicates that the reaction with NO_(3)•is themain oxidation pathway for unsaturated alcohols at night.Small molecule aldehydes and ketones were the main gas-phase organic products of the reaction of three aldehydes and ketones with NO_(3)•,and the total small molecule aldehydes and ketones yields can reach between 45%-60%.They mainly originate from the breakage of alkoxy radicals,and different breakage sites determine different product distributions.In addition,the SOA yields of the three unsaturated alcohols with NO_(3)•were 7.1%±1.0%,12.5%±1.9%and 30.0%±4.5%,respectively,whichweremuch higher than those of similarly structured substances with O_(3)or OH radicals(•OH).The results of high-resolution mass spectrometry shows that the main components of Secondary organic aerosol(SOA)of the three unsaturated alcohols are dimeric compounds containing several nitrate groups,which are formed through the polymerization of oxyalkyl radicals.
基金The authors are grateful for the Beijing Natural Science Foundation(Grant No.8242017)。
文摘This study presents an in-depth investigation into the shear strength characteristics of unsaturated soils,focusing on the influenceof shear rate and initial water saturation(S_(r0)).Utilizing the drained-vented(DV)triaxial test method,the present study investigated the shear strength behavior of silty clay under various shear rates and water saturation levels,and compared the outcomes with traditional suction-controlled(SC)and constant water content(CW)tests.The findingshighlight the pivotal role of excess pore water pressure dissipation during shearing,which significantlyaffects the shear strength of both saturated and unsaturated soils.Notably,for soils with high initial water saturation,a decrease in shear strength is observed with an increase in shear rate,which is attributed to the rise in pore water pressure.Conversely,for soils with low initial water saturation,the shear rate exhibits minimal impact on shear strength due to negligible water drainage.The research delineates the optimal shear rates for DV tests based on the initial water saturation:a slower rate of 0.0028 mm/min for samples with high water saturation(S_(r0)>66%)and a faster rate of 0.8 mm/min for samples with low water saturation(S_(r0)≤66%).A novel testing methodology for determining unsaturated soil shear strength under DV conditions is introduced,streamlining the measurement process and significantly reducing testing time.This method not only promises substantial cost savings but also aligns closely with natural engineering conditions,offering valuable guidance for geotechnical applications.
基金funded by the National Natural Science Foundation of China (No.52225402)Inner Mongolia Research Institute,China University of Mining and Technology-Beijing (IMRI23003)。
文摘In the gas-coal integrated mining field,the conventional design method of pipeline coal pillars leads to a large amount of coal pillars being unrecovered and overlooks the pipeline's safety requirements.Considering the coal pillar recovery rate and pipeline's safety requirements,two new shaped coal pillar design approaches for subsurface pipelines were developed.Firstly,the deformation limitations for measuring pipeline safety are categorized into two:no deformation is permitted,and deformation is acceptable within elastic limits.Subsequently,integrating the key stratum theory(KST)and cave angle,a fishbone-shaped coal pillar design approach that does not permit pipeline deformation is established.Meanwhile,combined with the ground subsidence and the pipeline's elastic deformation limit,a grille-shaped coal pillar design approach that accepts deformation pipelines within elastic limits is established.Those two new approaches clarify parameters including mined width,coal pillar width and mined length.Finally,the case study shows that the designed mined width,coal pillar width and mined length of the fishbone-shaped coal pillar are 90,80,and 130 m,while those of the grille-shaped are 320,370,and640 m.Compared with the conventional method,the fishbone-shaped and grille-shaped coal pillar design approaches recovered coal pillar resources of 2.65×10~6and 5.81×10~6t on the premise of meeting the pipeline safety requirements,and the recovery rates increased by 20.5%and 45.0%,with expenditures representing only 56.46%and 20.02%of the respective benefits.These new approaches provide managers with diverse options for protecting pipeline safety while promoting coal pillar recovery,which is conducive to the harmonic mining of gas-coal resources.
基金financially supported by Natural Science Foundation of Anhui Provincial Department of Education(2022AH050337)State Key Laboratory of Safety and Health for Metal Mines(2022-JSKSSYS-04)the Project of National Key Research and Development Program(2022YFC3901405).
文摘Nitrogen oxides(NO_(x))and particulate matter(PM)present significant risks to both human health and environmental sustainability.The Integrated Dust Removal and Denitrification Technology(DRDt)offers a more efficient and cost-effective solution for achieving ultralow industrial flue gas emissions;however,its effectiveness is undermined by low catalyst load rates and poor stability in filter materials.This study addresses these limitations by modifying conventional PTFE filter media(PTFE-Tim)through the incorporation of sodium alginate(SA)and dopamine(DA)as modifiers,resulting in two new filter materials:PTFE-SA-MOF and PTFE-DA-MOF.By optimizing the parameters of an orthogonal experimental design,we identified the ideal preparation conditions for these composite materials.The addition of SA and DA enhanced the bonding between the catalyst(Mn-Cu-MOF)crystal particles and the PTFE fibers through mechanisms such as ion exchange,hydrogen bonding,and adhesion.Consequently,the catalyst loading rate and stability of the DRDt filters were significantly improved.Specifically,the PTFE-SA-MOF and PTFE-DA-MOF filters achieved high catalyst loading rates of 15.97% and 15.86%,these values represent improvements of 2.53 and 2.51 times,while maintaining excellent stability,with mass retention rates of 98.64% and 98.27%,respectively,over the conventional PTFE-Tim filter.
基金supported by the National Natural Science Foundation of China(Grant.Nos.52364004,52464005)the Youth Talent Growth Project of Guizhou Provincial Department of Education(Grant No.QianJiaoJi[2024]18).
文摘Injection rate is crucial for determining the hydraulic fracturing effectiveness;however,the effects of the injection rate on the pore and fracture structure(PFS)and fluid infiltration during injection pressurization have rarely been explored.In this study,the cylindrical sandstone samples were hydraulically fractured at various injection rates on a self-developed integrated nuclear magnetic resonance(NMR)and hydraulic fracturing experimental system.The results show that low injection rates predominantly resulted in macropore-scale damage by creating intergranular cracks,whereas high injection rates facilitated micropore-scale damage,probably owing to the adsorption swelling effect of clay minerals within pores.Additionally,the water contents of the samples with low injection rates exhibited a continuous increase,whereas those of the samples with high injection rates initially increased and subsequently stabilized.Magnetic resonance imaging(MRI)indicated that fluid infiltration during the fracturing process exhibited high anisotropy owing to the inherent heterogeneous PFS distributions around the wellbore.Moreover,a primary fluid infiltration path exists that aligns with the initiation direction of the hydraulic fractures.However,the fluid infiltration damage distance along the hydraulic fracture direction decreased with increasing injection rate,whereas the fluid infiltration damage distance perpendicular to the hydraulic fracture direction was approximately equal to the characteristic length,regardless of the injection rate.Finally,we recommend using the pore damage during fluid pressurization as the basis for selecting the proppant size and employing a primary fluid infiltration path to predict hydraulic fracture initiation.These findings provide valuable insights into the design of hydraulic fracturing in tight gas reservoirs.
基金This research was funded by the National Natural Science Foundation of China(No.62272124)the National Key Research and Development Program of China(No.2022YFB2701401)+3 种基金Guizhou Province Science and Technology Plan Project(Grant Nos.Qiankehe Paltform Talent[2020]5017)The Research Project of Guizhou University for Talent Introduction(No.[2020]61)the Cultivation Project of Guizhou University(No.[2019]56)the Open Fund of Key Laboratory of Advanced Manufacturing Technology,Ministry of Education(GZUAMT2021KF[01]).
文摘In the assessment of car insurance claims,the claim rate for car insurance presents a highly skewed probability distribution,which is typically modeled using Tweedie distribution.The traditional approach to obtaining the Tweedie regression model involves training on a centralized dataset,when the data is provided by multiple parties,training a privacy-preserving Tweedie regression model without exchanging raw data becomes a challenge.To address this issue,this study introduces a novel vertical federated learning-based Tweedie regression algorithm for multi-party auto insurance rate setting in data silos.The algorithm can keep sensitive data locally and uses privacy-preserving techniques to achieve intersection operations between the two parties holding the data.After determining which entities are shared,the participants train the model locally using the shared entity data to obtain the local generalized linear model intermediate parameters.The homomorphic encryption algorithms are introduced to interact with and update the model intermediate parameters to collaboratively complete the joint training of the car insurance rate-setting model.Performance tests on two publicly available datasets show that the proposed federated Tweedie regression algorithm can effectively generate Tweedie regression models that leverage the value of data fromboth partieswithout exchanging data.The assessment results of the scheme approach those of the Tweedie regressionmodel learned fromcentralized data,and outperformthe Tweedie regressionmodel learned independently by a single party.
基金supported in part by the Key Research and Development Program of Jiangsu Province(Grant No.BE2020084-2)in part by the National Key Research and Development Program of China(Grant No.2020YFB1600104)+4 种基金in part by the Key Research and Development Special Project of school and local cooperation in Lvliang(Grant No.2023XDHZ18)in part by Southeast University-China Mobile Research Institute Joint Innovation Centerin part by the National Natural Science Foundation of China(Grant No.62371119)in part by the Key Research and Development Program of Jiangsu Province(Grant No.BE2022059-3)in part by the Zhi Shan Young Scholar Program of Southeast University。
文摘Federated Learning(FL)is an emerging machine learning framework designed to preserve privacy.However,the continuous updating of model parameters over uplink channels with limited throughput leads to a huge communication overload,which is a major challenge for FL.To address this issue,we propose an adaptive gradient quantization approach that enhances communication efficiency.Aiming to minimize the total communication costs,we consider both the correlation of gradients between local clients and the correlation of gradients between communication rounds,namely,in the time and space dimensions.The compression strategy is based on rate distortion theory,which allows us to find an optimal quantization strategy for the gradients.To further reduce the computational complexity,we introduce the Kalman filter into the proposed approach.Finally,numerical results demonstrate the effectiveness and robustness of the proposed rate-distortion optimization adaptive gradient quantization approach in significantly reducing the communication costs when compared to other quantization methods.
基金the support of Prince Sultan University for paying the article processing charges(APC)of this publication.
文摘This work aimed to construct an epidemic model with fuzzy parameters.Since the classical epidemic model doesnot elaborate on the successful interaction of susceptible and infective people,the constructed fuzzy epidemicmodel discusses the more detailed versions of the interactions between infective and susceptible people.Thenext-generation matrix approach is employed to find the reproduction number of a deterministic model.Thesensitivity analysis and local stability analysis of the systemare also provided.For solving the fuzzy epidemic model,a numerical scheme is constructed which consists of three time levels.The numerical scheme has an advantage overthe existing forward Euler scheme for determining the conditions of getting the positive solution.The establishedscheme also has an advantage over existing non-standard finite difference methods in terms of order of accuracy.The stability of the scheme for the considered fuzzy model is also provided.From the plotted results,it can beobserved that susceptible people decay by rising interaction parameters.
基金Project(2015CB060200)supported by the National Basic Research Program of ChinaProjects(51322403,51274254)supported by the National Natural Science Foundation of ChinaProjects(2015cx005,2016cx017)supported by Innovation Plan of Central South University
文摘The strength of rock materials is largely affected by water and loading conditions, but there are few studies on mechanical properties of saturated rocks at high strain rates. Through compressive tests on dry and saturated sandstone specimens, it was found that the dynamic compressive strength of both dry and saturated sandstone specimens increased with the increase of strain rates. The saturated rock specimens showed stronger rate dependence than the dry ones. The water affecting factor （WAF）, as the ratio of the strength under dry state to that under saturated state, was introduced to describe the influence of water on the compressive strength at different strain rates. The WAF under static load was close to 1.38, and decreased with the increase of strain rate. When the strain rate reached 190 s^-1, the WAF reduced to 0.98. It indicates that the compressive strength of saturated specimens can be higher than that of dry ones when the strain rate is high enough. Furthermore, the dual effects of water and strain rate on the strength of rock were discussed based on sliding crack model, which provided a good explanation for the experimental results.
基金NSFC(No.71974017)LIS Outstanding Talents Introducing Program,Bureau of Development and Planning of CAS(2022).
文摘Purpose:The notable increase in retraction papers has attracted considerable attention from diverse stakeholders.Various sources are now offering information related to research integrity,including concerns voiced on social media,disclosed lists of paper mills,and retraction notices accessible through journal websites.However,despite the availability of such resources,there remains a lack of a unified platform to consolidate this information,thereby hindering efficient searching and cross-referencing.Thus,it is imperative to develop a comprehensive platform for retracted papers and related concerns.This article aims to introduce“Amend,”a platform designed to integrate information on research integrity from diverse sources.Design/methodology/approach:The Amend platform consolidates concerns and lists of problematic articles sourced from social media platforms(e.g.,PubPeer,For Better Science),retraction notices from journal websites,and citation databases(e.g.,Web of Science,CrossRef).Moreover,Amend includes investigation and punishment announcements released by administrative agencies(e.g.,NSFC,MOE,MOST,CAS).Each related paper is marked and can be traced back to its information source via a provided link.Furthermore,the Amend database incorporates various attributes of retracted articles,including citation topics,funding details,open access status,and more.The reasons for retraction are identified and classified as either academic misconduct or honest errors,with detailed subcategories provided for further clarity.Findings:Within the Amend platform,a total of 32,515 retracted papers indexed in SCI,SSCI,and ESCI between 1980 and 2023 were identified.Of these,26,620(81.87%)were associated with academic misconduct.The retraction rate stands at 6.64 per 10,000 articles.Notably,the retraction rate for non-gold open access articles significantly differs from that for gold open access articles,with this disparity progressively widening over the years.Furthermore,the reasons for retractions have shifted from traditional individual behaviors like falsification,fabrication,plagiarism,and duplication to more organized large-scale fraudulent practices,including Paper Mills,Fake Peer-review,and Artificial Intelligence Generated Content(AIGC).Research limitations:The Amend platform may not fully capture all retracted and concerning papers,thereby impacting its comprehensiveness.Additionally,inaccuracies in retraction notices may lead to errors in tagged reasons.Practical implications:Amend provides an integrated platform for stakeholders to enhance monitoring,analysis,and research on academic misconduct issues.Ultimately,the Amend database can contribute to upholding scientific integrity.Originality/value:This study introduces a globally integrated platform for retracted and concerning papers,along with a preliminary analysis of the evolutionary trends in retracted papers.
基金supported by the National Natural Science Foundation of China(Grant No.62305388)the Postgraduate Scientific Research Innovation Project of Hunan Province(Grant No.QL20230007).
文摘Orbital-angular-momentum(OAM)multiplexing technology offers a significant dimension to enlarge communication capacity in free-space optical links.The coherent beam combining(CBC)system can simultaneously realize OAM multiplexing and achieve high-power laser output,providing substantial advantages for long-distance communication.Herein,we present an integrated CBC system for freespace optical links based on OAM multiplexing and demultiplexing technologies for the first time,to the best of our knowledge.A method to achieve flexible OAM multiplexing and efficient demultiplexing based on the CBC system is proposed and demonstrated both theoretically and experimentally.The experimental results exhibit a low bit error rate of 0.47%and a high recognition precision of 98.58%throughout the entire data transmission process.By employing such an ingenious strategy,this work holds promising prospects for enriching ultra-long-distance structured light communication in the future.
文摘Through different dose-rate switching evaluation methods,the radiation-response rules of operational amplifiers are studied when the irradiation dose rate is switched from high to low under different radiation temperatures and total doses. The experimental results indicate that the response characteristics could be affected by the switching total doses, irradiation temperatures,and dose rates individually or together. Accelerated evaluation on the ELDRS can be realized by adopting a proper dose-rate switching method. Meanwhile, the irradiation time can also be reduced. Finally, the mechanisms of the difference between various radiation responses are analyzed.
基金Project supported by the Research Funds of the Key Laboratory of Fuel Cell Technology of Guangdong Province,ChinaProject(7411793079907)supported by the Guangzhou Special Foundation for Applied Basic Research+1 种基金Project(2013A15GX048)supported by the Dalian Science and Technology Project Foundation,ChinaProject(21376035)supported by the National Natural Science Foundation of China
文摘Synthesis of the spinel structure lithium manganese oxide （LiMn2O4） by supercritical hydrothermal （SH） accelerated solid state reaction （SSR） route was studied. The impacts of the reaction pressure, reaction temperature and reaction time of SH route, and the calcination temperature of SSR route on the purity, particle morphology and electrochemical properties of the prepared LiMn2O4 materials were studied. The experimental results show that after 15 min reaction in SH route at 400 ℃ and 30 MPa, the reaction time of SSR could be significantly decreased, e.g. down to 3 h with the formation temperature of 800 ℃, compared with the conventional solid state reaction method. The prepared LiMn2O4 material exhibits good crystallinity, uniform size distribution and good electrochemical performance, and has an initial specific capacity of 120 mA.h/g at a rate of 0.1C （1C=148 mA/g） and a good rate capability at high rates, even up to 50C.
基金supported in part by the National Natural Science Foundation of China under Grant 61901378,61941119,61901379in part by the Natural Science Basic Research Plan in Shaanxi Province of China under Grant 2019JQ-253+5 种基金in part by the open research fund of National Mobile Communications Research Laboratory,Southeast University under Grant 2020D04in part by China Postdoctoral Science Foundation under Grant BX20190287in part by the Aerospace Science and Technology Innovation Fund of China Aerospace Science and Technology Corporationin part by the Shanghai Aerospace Science and Technology Innovation Fund(No.SAST2018045)in part by the China Fundamental Research Fund for the Central Universities(No.3102018QD096)in part by the Seed Foundation of Innovation and Creation for Graduate Students in Northwestern Polytechnical University(No.CX2020152).
文摘Reconfigurable intelligent surface(RIS)has been proposed as a potential solution to improve the coverage and spectrum efficiency for future wireless communication.However,the privacy of users’data is often ignored in previous works,such as the user’s location information during channel estimation.In this paper,we propose a privacy-preserving design paradigm combining federated learning(FL)with RIS in the mmWave communication system.Based on FL,the local models are trained and encrypted using the private data managed on each local device.Following this,a global model is generated by aggregating them at the central server.The optimal model is trained for establishing the mapping function between channel state information(CSI)and RIS’configuration matrix in order to maximize the achievable rate of the received signal.Simulation results demonstrate that the proposed scheme can effectively approach to the theoretical value generated by centralized machine learning(ML),while protecting user’privacy.
基金Supported by The China National Key S and T Projects for Major Infectious Diseases,No. 2008ZX10002-26
文摘AIM:To evaluate the effectiveness of omega-3 polyunsaturated fatty acid(ω-3 PUFA) administration on liver regeneration after 90% partial hepatectomy(PH) in rats.METHODS:ω-3 PUFAs were intravenously injected in the ω-3 PUFA group before PH surgery.PH,sparing only the caudate lobe,was performed in both the control and the ω-3 PUFA group.Survival rates,liver weight/body weight ratios,liver weights,HE staining,transmission electron microscope imaging,nuclearassociated antigen Ki-67,enzyme-linked immunosorbent assay and signal transduction were evaluated to analyze liver regeneration.RESULTS:All rats in the control group died within 30 h after hepatectomy.Survival rates in the ω-3 PUFA group were 20/20 at 30 h and 4/20 1 wk after PH.Liver weight/body weight ratios and liver weights increased significantly in the ω-3 PUFA group.The structure of sinusoidal endothelial cells and space of Disse was greatly restored in the ω-3 PUFA group compared to the control group after PH.In the ω-3 PUFA group,interleukin(IL)-4 and IL-10 levels were significantly increased whereas IL-6 and tumor necrosis factor-levels were dramatically decreased.In addition,activation of protein kinase B(Akt) and of signal transducer and activator of transcription 3 signaling pathway were identified at an earlier time after PH in the ω-3 PUFA group.CONCLUSION:Omega-3 polyunsaturated fatty acids may prevent acute liver failure and promote liver regeneration after 90% hepatectomy in rats.
基金Projects(50422283,51208054) supported by the National Natural Science Foundation of China
文摘In order to analyze the impact of stretching-segment on the saturated flow rate of signalized intersection approach, an improved cellular automation model was proposed to estimate its saturated flow rate. The NaSch model was improved by adding different slow probabilities, turning deceleration rules and modified lane changing rules. The relationship between the saturated flow rate of stretching-segments and adjacent lanes was tested in numerical simulation. The length of stretching-segment, cycle length and green time were selected as impact factors of the cellular automation model. The simulation result indicates that the geometrics design of stretching-segment and the traffic signal timing scenario have major effects on the saturated flow rate of the intersection approach. The saturated flow rate will continually increase with increasing stretching-segment length until it reaches a threshold. After reaching the threshold, the stretching-segment can be treated as a separate lane. The green time is approximately linearly related to the threshold length of the stretching-segment. An optimum cycle length exists when the length of the stretching-segment is not long enough, and it is approximately linearly related to the length of stretching-segment.
基金supported by the National Natural Science Foundation of China (Nos. 41571130022, 91544223, 21473009)
文摘Rate constants for the reactions of ozone with 1-octen-3-ol, 1-nonen-3-ol and 1-nonen-4-ol have been determined at 298 ±1 K and atmospheric pressure for the first time. The experiments were performed in a 100-L FEP Teflon film bag using absolute rate method; the rate constants were （1.91 ± 0.19） ×10^-17, （1.89 ± 0.20） × 10^-17, and （0.83 ± 0.08） × 10^-17 cm^3/（molecule.sec） for 1-octen-3-ol, 1-nonen-3-ol, and 1-nonen-4-ol, respectively. The rate constants have been compared with those of unsaturated alcohols structural homologs, and used to estimate the reaction reactivity. The electronegativity of carbon-carbon double bond was calculated by atomic charges analysis. The calculated results show that the electronic effect of the lone pair electrons of hydroxyl oxygen is the main cause of the difference in rate coefficient. According to the obtained rate constants, the atmospheric lifetimes of studied unsaturated alcohols were also estimated, which indicates that the reaction with ozone is an important loss pathway in the atmosphere, especially in polluted areas.
