In the development of coalbed methane(CBM)reservoirs using multistage fractured horizontal wells,there often exist areas that are either repeatedly stimulated or completely unstimulated between fracturing stages,leadi...In the development of coalbed methane(CBM)reservoirs using multistage fractured horizontal wells,there often exist areas that are either repeatedly stimulated or completely unstimulated between fracturing stages,leading to suboptimal reservoir performance.Currently,there is no well-established method for accurately evaluating the effectiveness of such stimulation.This study introduces,for the first time,the concept of the Fracture Network Bridging Coefficient(FNBC)as a novel metric to assess stimulation performance.By quantitatively coupling the proportions of unstimulated and overstimulated volumes,the FNBC effectively characterizes the connectivity and efficiency of the fracture network.A background grid calibration method is developed to quantify the stage-controlled volume,effectively stimulated volume,unstimulated volume,and repeatedly stimulated volume among different stages of horizontal wells.Furthermore,an optimization model is constructed by taking the FNBC as the objective function and the fracturing injection rate and fluid volume as optimization variables.The Simultaneous Perturbation Stochastic Approximation(SPSA)algorithm is employed to iteratively perturb and optimize these variables,progressively improving the FNBC until the optimal displacement rate and fluid volume corresponding to the maximum FNBC are obtained.Field application in a typical CBM multistage fractured horizontal well in China demonstrates that the FNBC increased from 0.358 to 0.539(a 50.6% improvement),with the injection rate rising from 16 m^(3)/min to 24 m^(3)/min and the average fluid volume per stage increasing from 2490 m^(3) to 3192 m^(3),significantly enhancing the stimulation effectiveness.This research provides theoretical support for designing high-efficiency stimulation strategies in unconventional reservoirs under dynamic limits.展开更多
This study experimentally investigates complex wave structures and flow characteristics in a transonic free jet using two high-resolution optical diagnostics techniques:tomographic particle image velocimetry(Tomo-PIV)...This study experimentally investigates complex wave structures and flow characteristics in a transonic free jet using two high-resolution optical diagnostics techniques:tomographic particle image velocimetry(Tomo-PIV)and tomographic background oriented schlieren(Tomo-BOS).The measurements reveal three typical flow features in the jet:the potential core,shock cells,and shear layers.Notably,the shear layer displays significant velocity gradient variations across the lip line and plays a critical role in pressure regulation.The first invariant of the velocity gradient tensor,P,effectively characterizes local compressibility effects,facilitating the identification of key flow structures.In conjunction with-Q_(s)analysis,the results emphasize shear-driven deformation and the radial decay of wave intensity.Overall,the study demonstrates that current experimental techniques enable preliminary quantitative evaluation of transonic wave phenomena,providing valuable tools for the analysis of compressible flows.展开更多
The rapid identification of γ-emitting radionuclides with low activity levels in public areas is crucial for nuclear safety.However,classical methods rely on full-energy peaks in the integral spectrum,requiring suffi...The rapid identification of γ-emitting radionuclides with low activity levels in public areas is crucial for nuclear safety.However,classical methods rely on full-energy peaks in the integral spectrum,requiring sufficient count accumulation for evaluation,thereby limiting response time.The sequential Bayesian approach,which utilizes prior information and considers both photon energies and interarrival times,can significantly enhance the performance of radionuclides identification.This study proposes a theoretical optimization method for the traditional sequential Bayesian approach.Each photon is processed sequentially,and the corresponding posterior probability is updated in real time using a noninformative prior from the Bayesian theory.By comparing the posterior probabilities of the background and radionuclides based on the energy variance and time interval,the type of γ-rays can be identified(background characteristic γ-rays,Compton plateaus γ-rays,or radionuclide-specific characteristic γ-rays).By integrating the information from these multiple characteristic γ-rays,the presence and type of radionuclides were determined based on the final decision function and a set threshold.Based on theoretical research,verification experiments were conducted using a LaBr_(3)(Ce)detector in both low-and natural background radiation environments with typical radionuclides(^(137)Cs,^(60)Co,and ^(133)Ba).The results show that this approach can identify ^(137)Cs in 7.9 s and 8.5 s(source dose rate contribution:approximately 6.5×10^(−3)μGy/h),^(60)Co in 8.1 s and 9.8 s(approximately 4.8×10^(−2)μGy/h),and ^(133)Ba in 4.05 s and 5.99 s(approximately 3.4×10^(−2)μGy/h)under low and natural background radiation,respectively,with a miss rate below 0.01%.This demonstrates the effectiveness of the proposed approach for fast radionuclides identification,even at low activity levels and highlights its potential for enhancing public safety in diverse radiation environments.展开更多
Highly oriented pyrolytic graphite (HOPG) is frequently adopted as the reaction target in12C+12C fusion reaction experiments owing to its superior purity.In this study,we investigate the reaction yield dependence on t...Highly oriented pyrolytic graphite (HOPG) is frequently adopted as the reaction target in12C+12C fusion reaction experiments owing to its superior purity.In this study,we investigate the reaction yield dependence on the accumulated beam dose on HOPG target using a novel detection system consisting of a time-projection chamber and silicon array.The reaction yields are significantly reduced under intense beam bombardment owing to radiation damage to the HOPG surface.The α_(0) and p_(0,1) yields decrease by 51.5% and 25%,respectively,when the ^(12)C^(2+) beam dose accumulates at 5 C.Using the novel detection system and HOPG target,the α0yield is determined to be 2.68_(-1.69)^(+4.69)×10^(-17/12) C after correcting for the yield loss due to radiation damage.Our result represents the highest sensitivity achieved to date in direct measurements of ^(12)C(12C,α_(0))^(20)Ne.展开更多
Background:Over the past few decades,a threefold increase in obesity and type 2 diabetes(T2D)has placed a heavy burden on the health-care system and society.Previous studies have shown correlations between obesity,T2D...Background:Over the past few decades,a threefold increase in obesity and type 2 diabetes(T2D)has placed a heavy burden on the health-care system and society.Previous studies have shown correlations between obesity,T2D,and neurodegenera-tive diseases,including dementia.It is imperative to further understand the relation-ship between obesity,T2D,and cognitive deficits.Methods:This investigation tested and evaluated the cognitive impact of obesity and T2D induced by high-fat diet(HFD)and the effect of the host genetic background on the severity of cognitive decline caused by obesity and T2D in collaborative cross(CC)mice.The CC mice are a genetically diverse panel derived from eight inbred strains.Results:Our findings demonstrated significant variations in the recorded phenotypes across different CC lines compared to the reference mouse line,C57BL/6J.CC037 line exhibited a substantial increase in body weight on HFD,whereas line CC005 ex-hibited differing responses based on sex.Glucose tolerance tests revealed significant variations,with some lines like CC005 showing a marked increase in area under the curve(AUC)values on HFD.Organ weights,including brain,spleen,liver,and kidney,varied significantly among the lines and sexes in response to HFD.Behavioral tests using the Morris water maze indicated that cognitive performance was differentially affected by diet and genetic background.Conclusions:Our study establishes a foundation for future quantitative trait loci map-ping using CC lines and identifying genes underlying the comorbidity of Alzheimer's disease(AD),caused by obesity and T2D.The genetic components may offer new tools for early prediction and prevention.展开更多
Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimila...Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimilation is quite challenging.This is because there is limited knowledge about the cross-component background error covariance(BEC)between LST and atmospheric state variables.This study aims to clarify whether there is a relationship between the error of LST and atmospheric variables,and whether this relationship varies spatially and temporally.To this end,the BEC coupled with atmospheric variables and LST was constructed(LST-BEC),and its characteristics were analyzed based on the 2023 mei-yu season.The general characteristics of LST-BEC show that the LST is mainly correlated with the atmospheric temperature and the correlation decreases gradually with a rise in atmospheric height,and the error standard deviation of the LST is noticeably larger than that of the low-level atmospheric temperature.The spatiotemporal characteristics of LST-BEC on the heavy-rain day and light-rain day show that the error correlation and error standard deviation of LST and low-level atmospheric temperature and humidity are closely related to the weather background,and also have obvious diurnal variations.These results provide valuable information for strongly coupled land-atmosphere assimilation.展开更多
Accurately identifying building distribution from remote sensing images with complex background information is challenging.The emergence of diffusion models has prompted the innovative idea of employing the reverse de...Accurately identifying building distribution from remote sensing images with complex background information is challenging.The emergence of diffusion models has prompted the innovative idea of employing the reverse denoising process to distill building distribution from these complex backgrounds.Building on this concept,we propose a novel framework,building extraction diffusion model(BEDiff),which meticulously refines the extraction of building footprints from remote sensing images in a stepwise fashion.Our approach begins with the design of booster guidance,a mechanism that extracts structural and semantic features from remote sensing images to serve as priors,thereby providing targeted guidance for the diffusion process.Additionally,we introduce a cross-feature fusion module(CFM)that bridges the semantic gap between different types of features,facilitating the integration of the attributes extracted by booster guidance into the diffusion process more effectively.Our proposed BEDiff marks the first application of diffusion models to the task of building extraction.Empirical evidence from extensive experiments on the Beijing building dataset demonstrates the superior performance of BEDiff,affirming its effectiveness and potential for enhancing the accuracy of building extraction in complex urban landscapes.展开更多
Generally speaking,the precursors of ozone(O_(3)),nitrogen oxides and volatile organic compounds are very low in desert areas due to the lack of anthropogenic emissions and natural emissions,and thus O_(3)concentratio...Generally speaking,the precursors of ozone(O_(3)),nitrogen oxides and volatile organic compounds are very low in desert areas due to the lack of anthropogenic emissions and natural emissions,and thus O_(3)concentrations are relatively low.However,high summer background concentrations of about 100μg/m^(3)or 60 ppb were found in the Alxa Desert in the highland of northwest China based on continuous summer observations from 2019 to 2021,which was higher than the most of natural background areas or clean areas in world for summer O_(3)background concentrations.The high O_(3)background concentrations were related to surface features and altitude.Heavy-intensity anthropogenic activity areas in desert areas can cause increased O_(3)concentrations or pollution,but also generated O_(3)depleting substances such as nitrous oxide,which eventually reduced the regional O_(3)baseline values.Nitrogen dioxide(NO2)also had a dual effect on O_(3)generation,showing promotion at low concentrations and inhibition at high concentrations.In addition,sand-dust weather reduced O_(3)clearly,but O_(3)eventually stabilized around the background concentration values and did not vary with sand-dust particulate matter.展开更多
A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and...A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and development of the NMI model and then emphasize that the NMI model represents a new tool for identifying the basic physics of how climate change influences mid-to-high latitude weather extremes.The building of the NMI model took place over three main periods.In the 1990s,a nonlinear Schr?dinger(NLS)equation model was presented to describe atmospheric blocking as a wave packet;however,it could not depict the lifetime(10-20 days)of atmospheric blocking.In the 2000s,we proposed an NMI model of atmospheric blocking in a uniform basic flow by making a scale-separation assumption and deriving an eddyforced NLS equation.This model succeeded in describing the life cycle of atmospheric blocking.In the 2020s,the NMI model was extended to include the impact of a changing climate mainly by altering the basic zonal winds and the magnitude of the meridional background potential vorticity gradient(PVy).Model results show that when PVy is smaller,blocking has a weaker dispersion and a stronger nonlinearity,so blocking can be more persistent and have a larger zonal scale and weaker eastward movement,thus favoring stronger weather extremes.However,when PVy is much smaller and below a critical threshold under much stronger winter Arctic warming of global warming,atmospheric blocking becomes locally less persistent and shows a much stronger westward movement,which acts to inhibit local cold extremes.Such a case does not happen in summer under global warming because PVy fails to fall below the critical threshold.Thus,our theory indicates that global warming can render summer-blocking anticyclones and mid-to-high latitude heatwaves more persistent,intense,and widespread.展开更多
BACKGROUND Inadequate glycemic control in patients with type 2 diabetes(T2DM)is a major public health problem and a significant risk factor for the progression of diabetic complications.AIM To evaluate the effects of ...BACKGROUND Inadequate glycemic control in patients with type 2 diabetes(T2DM)is a major public health problem and a significant risk factor for the progression of diabetic complications.AIM To evaluate the effects of intensive and supportive glycemic management strategies over a 12-month period in individuals with T2DM with glycated hemoglobin(HbA1c)≥10%and varying backgrounds of glycemic control.METHODS This prospective observational study investigated glycemic control in patients with poorly controlled T2DM over 12 months.Participants were categorized into four groups based on prior glycemic history:Newly diagnosed,previously well controlled with recent worsening,previously off-target but now worsening,and HbA1c consistently above 10%.HbA1c levels were monitored quarterly,and patients received medical,educational,and dietary support as needed.The analysis focused on the success rates of good glycemic control and the associated factors within each group.RESULTS The study showed significant improvements in HbA1c levels in all participants.The most significant improvement was observed in individuals newly diagnosed with diabetes:65%achieved an HbA1c target of≤7%.The results varied between participants with different glycemic control histories,followed by decreasing success rates:39%in participants with previously good glycemic control,21%in participants whose glycemic control had deteriorated compared to before,and only 10%in participants with persistently poor control,with mean HbA1c levels of 6.3%,7.7%,8.2%,and 9.7%,respectively.After one year,65.2%of the“newly diagnosed patients”,39.3%in the“previously controlled group”,21.9%in the“previously off-target but now worsened'”group and 10%in the“poorly controlled from the start”group had achieved HbA1c levels of 7 and below.CONCLUSION In poorly controlled diabetes,the rate at which treatment goals are achieved is associated with the glycemic background characteristics,emphasizing the need for tailored strategies.Therefore,different and comprehensive treatment approaches are needed for patients with persistent uncontrolled diabetes.展开更多
INTRODUCTION WITH HISTORICAL AND DIPLOMATIC BACKGROUND.Situated at the southern part of the Adriatic coast,Montenegro is a small country in size but is gaining importance in international economic and geopolitical aff...INTRODUCTION WITH HISTORICAL AND DIPLOMATIC BACKGROUND.Situated at the southern part of the Adriatic coast,Montenegro is a small country in size but is gaining importance in international economic and geopolitical affairs.Over the past decade,it has found itself balancing between the East and the West-aspiring to join the European Union(EU),while staying open to global partnerships,particularly with China.展开更多
The Hard X-ray Imager(HXI)payload,a component of China’s Advanced Space-based Solar Observatory satellite,is designed to observe solar X-ray emissions in the 30-200 keV range,with the aim of investigating nonthermal ...The Hard X-ray Imager(HXI)payload,a component of China’s Advanced Space-based Solar Observatory satellite,is designed to observe solar X-ray emissions in the 30-200 keV range,with the aim of investigating nonthermal physical processes during solar flares.Before launch,Geant4 simulations were employed to assess the onorbit background of the HXI instrument,evaluating its performance and potential to achieve its scientific objectives.This study addresses issues identified in previous simulations and conducts further analyses to examine the distribution of background counts across the 99 detectors.The results demonstrate alignment between simulations and observations at low and medium geomagnetic latitudes;however,challenges persist at high geomagnetic latitudes due to limitations in the current albedo photon model.This investigation provides insights into background sources from various particles,enhances understanding of space background characteristics,and offers guidance for background subtraction in imaging processes.展开更多
Animal species exhibit a wide range of coloration and patterns,which are under strong selection and often linked to individual quality,influencing mate choice,recognition,signaling,and interspecific interactions such ...Animal species exhibit a wide range of coloration and patterns,which are under strong selection and often linked to individual quality,influencing mate choice,recognition,signaling,and interspecific interactions such as predator avoidance.In amphibians,coloration can vary based on individual traits as well as environmental conditions,including the coloration of their environment.In this study,we described the dorsal coloration(body coloration reticulated by dark patches)in 676 Western spadefoot toads(Pelobates cultripes)from the French Atlantic coast,comparing color variations across different substrates.In addition,we assessed color change in 18 toads transferred between bright and dark substrates.We demonstrated that the dorsal coloration varies based on capture locations(beach vs.inland)and associated substrate types(bright vs.dark),suggesting background color matching.We showed more pronounced effects in females,which might reflect varying predation risks.Experimentally,we showed that individuals can rapidly adjust their coloration to match the substrate within 24 h.Rapid color changes in response to substrate type indicate significant pigmentation plasticity.Bright individuals from sandy substrates showed less dorsal background(body)color change than dark inland individuals,while patch coloration responded differently depending on the substrate of origin.These findings highlight the complex interactions between substrate type,sex,and pigmentation plasticity.These interactions have potential costs and benefits,which might be linked to melanin production,which warrant further investigation.展开更多
Author:Hu Yan.This book provides a comprehensive overview of the background,causes,process,and impact of the British invasion of Xizang from 1903 to 1904,offering an in-depth analysis of the nature and detrimental act...Author:Hu Yan.This book provides a comprehensive overview of the background,causes,process,and impact of the British invasion of Xizang from 1903 to 1904,offering an in-depth analysis of the nature and detrimental actions of imperialist aggression.展开更多
The turbine blades operate under high temperature and high pressure conditions,and when using radiation thermometry,the influence of radiation from surrounding blades leads to measurement errors.To address this issue,...The turbine blades operate under high temperature and high pressure conditions,and when using radiation thermometry,the influence of radiation from surrounding blades leads to measurement errors.To address this issue,this paper develops a three-dimensional discretized dynamic radiation transfer model based on the blade shape of the turbine.The relationship between the radiation angle coefficient of the surrounding blades and the rotation angle of the blade under test is analyzed.The radiation angle coefficient is calculated using the triangular element method,and temperature inversion is performed based on the effective emissivity to compute the measurement error.The results show that under dynamic high temperature conditions,the temperature measurement error caused by reflection at the selected 60%leaf height point varies with the rotation angle,and the maximum reaches 25.58K.The angular coefficient exhibits periodic fluctuations with changes in rotation angle,and the maximum effective emissivity increases as the rotation angle increases.As the blade height increases,the impact of reflected radiation on radiometric temperature measurement errors shows a decreasing trend.This study provides a reference for radiation thermometry in dynamic high-temperature environments.展开更多
The precise determination of cross sections for key nuclear reactions within the Gamow window is crucial for advancing the study of stellar evolution and nucleosynthesis.However,extremely low reaction yields combined ...The precise determination of cross sections for key nuclear reactions within the Gamow window is crucial for advancing the study of stellar evolution and nucleosynthesis.However,extremely low reaction yields combined with the cosmic-ray-induced background make these measurements highly challenging,particularly for capture reactions.This work demonstrates the second configuration of the large-scale modular BGO detection array(LAMBDA-Ⅱ)designed to capture reaction measurements and introduces a method for suppressingγ-ray detection background in ground laboratories.By employing active and passive shielding,the background of LAMBDA-Ⅱwas significantly reduced by approximately two orders of magnitude,reaching 8.1×10^(-3)and 1.0×10^(-3)keV^(-1)h^(-1)in the 6-11 and 11-20 MeV energy ranges,respectively.When combined with a mA-scale intensity beam,this reduced background enables the investigation of several capture reactions of astrophysical interest in ground laboratories.展开更多
The Newtonian gravitational constant G is one of the most important fundamental constants of nature, but still remains resistant to the standard model of physics and disconnected from quantum theory. During the past &...The Newtonian gravitational constant G is one of the most important fundamental constants of nature, but still remains resistant to the standard model of physics and disconnected from quantum theory. During the past >100 years, hundreds of G values have been measured to be ranging around 6.66 to 6.7559 × 10−11 m3·kg−1·s−2 using macroscopic masses. More recently, however, a G value ((6.04 ± 0.06) × 10−11 m3·kg−1·s−2) measured using millimetre-sized masses shows significant deviation (by ~9%) from the reference G value, which the authors explained is resulted from “the known systematic uncertainties”. However, based on the observation of historical G values and the protocol of the millimetre-sized masses based experiment, here we proposed a theory that this deviation is not from “systematic uncertainties” but actually G will rapidly decrease when masses sphere diameter is less than 0.02 metres. Moreover, this theory predicted the G value will be 5.96 × 10−11 m3·kg−1·s−2 between masses whose diameter are 2 millimetres (0.002 metres), which matches the measured G value very well.展开更多
Objective:Lanqin oral liquid(LOL),as a traditional Chinese medicine prescription,has obvious clinical efficacy in the treatment of pharyngeal inflammation.Exploring the distribution of LOL prototype components and met...Objective:Lanqin oral liquid(LOL),as a traditional Chinese medicine prescription,has obvious clinical efficacy in the treatment of pharyngeal inflammation.Exploring the distribution of LOL prototype components and metabolites in plasma is of great significance for understanding potentially effective compounds.The aim of this study is to elucidate the metabolites and main metabolic pathways of LQL in vivo.Methods:In this study,a reliable approach integrated background subtraction and mass defect filtering(MDF),based on quadrupole time-of-flight mass spectrometry(QTOF-MS)technology,was performed to systematically scan the metabolites of LOL in rat plasma.In addition,according to the prototype mass spectrometry fragmentation pattern and combined with metabolic pathway analysis,a biotransformation oriented analysis strategy was established and applied to the identification of metabolites in LOL in vivo.Results:As a result,159 compounds(58 prototypes and 101 metabolites)were identified or tentatively characterized in drug-containing plasma,including 74 flavonoids,30 alkaloids,34 terpenoids,five phenylpropanoids,six phenolic acids,five fatty acids,and five other type components.The main metabolic pathways include methylation,demethylation,hydroxylation,hydrogenation,glucuronidation,and sulfation.Conclusions:This study provides an overall characterization of the metabolites of LOL in vivo for the first time,providing a solid material basis for exploring the therapeutic effects and pharmacological mechanisms of LOL.展开更多
The quantitative trait loci(QTL)-by-environment(Q × E) interaction effect is hard to detect because there are no effective ways to control the genomic background. In this study, we propose a linear mixed model th...The quantitative trait loci(QTL)-by-environment(Q × E) interaction effect is hard to detect because there are no effective ways to control the genomic background. In this study, we propose a linear mixed model that simultaneously analyzes data from multiple environments to detect Q × E interactions. This model incorporates two different kinship matrices derived from the genome-wide markers to control both main and interaction polygenic background effects. Simulation studies demonstrate that our approach is more powerful than the meta-analysis and inclusive composite interval mapping methods. We further analyze four agronomic traits of rice across four environments. A main effect QTL is identified for 1000-grain weight(KGW), while no QTL are found for tiller number. Additionally, a large QTL with a significant Q × E interaction is detected on chromosome 7 affecting grain number, yield, and KGW. This region harbors two important genes, PROG1 and Ghd7. Furthermore, we apply our mixed model to analyze lodging in barley across six environments. The six regions exhibiting Q × E interaction effects identified by our approach overlap with the SNPs previously identified using EM and MCMC-based Bayesian methods, further validating the robustness of our approach. Both simulation studies and empirical data analyses show that our method outperforms all other methods compared.展开更多
基金the financial support from National Natural Science Foundation of China(No.52474029)Strategic and Applied Scientific Research Project of PetroChina Company Limited(2023ZZ18,2023ZZ18YJ04).
文摘In the development of coalbed methane(CBM)reservoirs using multistage fractured horizontal wells,there often exist areas that are either repeatedly stimulated or completely unstimulated between fracturing stages,leading to suboptimal reservoir performance.Currently,there is no well-established method for accurately evaluating the effectiveness of such stimulation.This study introduces,for the first time,the concept of the Fracture Network Bridging Coefficient(FNBC)as a novel metric to assess stimulation performance.By quantitatively coupling the proportions of unstimulated and overstimulated volumes,the FNBC effectively characterizes the connectivity and efficiency of the fracture network.A background grid calibration method is developed to quantify the stage-controlled volume,effectively stimulated volume,unstimulated volume,and repeatedly stimulated volume among different stages of horizontal wells.Furthermore,an optimization model is constructed by taking the FNBC as the objective function and the fracturing injection rate and fluid volume as optimization variables.The Simultaneous Perturbation Stochastic Approximation(SPSA)algorithm is employed to iteratively perturb and optimize these variables,progressively improving the FNBC until the optimal displacement rate and fluid volume corresponding to the maximum FNBC are obtained.Field application in a typical CBM multistage fractured horizontal well in China demonstrates that the FNBC increased from 0.358 to 0.539(a 50.6% improvement),with the injection rate rising from 16 m^(3)/min to 24 m^(3)/min and the average fluid volume per stage increasing from 2490 m^(3) to 3192 m^(3),significantly enhancing the stimulation effectiveness.This research provides theoretical support for designing high-efficiency stimulation strategies in unconventional reservoirs under dynamic limits.
文摘This study experimentally investigates complex wave structures and flow characteristics in a transonic free jet using two high-resolution optical diagnostics techniques:tomographic particle image velocimetry(Tomo-PIV)and tomographic background oriented schlieren(Tomo-BOS).The measurements reveal three typical flow features in the jet:the potential core,shock cells,and shear layers.Notably,the shear layer displays significant velocity gradient variations across the lip line and plays a critical role in pressure regulation.The first invariant of the velocity gradient tensor,P,effectively characterizes local compressibility effects,facilitating the identification of key flow structures.In conjunction with-Q_(s)analysis,the results emphasize shear-driven deformation and the radial decay of wave intensity.Overall,the study demonstrates that current experimental techniques enable preliminary quantitative evaluation of transonic wave phenomena,providing valuable tools for the analysis of compressible flows.
基金supported by the Program for NIM-Basic Research Business Expenses Key Field Program,China(No.AKYCX2315).
文摘The rapid identification of γ-emitting radionuclides with low activity levels in public areas is crucial for nuclear safety.However,classical methods rely on full-energy peaks in the integral spectrum,requiring sufficient count accumulation for evaluation,thereby limiting response time.The sequential Bayesian approach,which utilizes prior information and considers both photon energies and interarrival times,can significantly enhance the performance of radionuclides identification.This study proposes a theoretical optimization method for the traditional sequential Bayesian approach.Each photon is processed sequentially,and the corresponding posterior probability is updated in real time using a noninformative prior from the Bayesian theory.By comparing the posterior probabilities of the background and radionuclides based on the energy variance and time interval,the type of γ-rays can be identified(background characteristic γ-rays,Compton plateaus γ-rays,or radionuclide-specific characteristic γ-rays).By integrating the information from these multiple characteristic γ-rays,the presence and type of radionuclides were determined based on the final decision function and a set threshold.Based on theoretical research,verification experiments were conducted using a LaBr_(3)(Ce)detector in both low-and natural background radiation environments with typical radionuclides(^(137)Cs,^(60)Co,and ^(133)Ba).The results show that this approach can identify ^(137)Cs in 7.9 s and 8.5 s(source dose rate contribution:approximately 6.5×10^(−3)μGy/h),^(60)Co in 8.1 s and 9.8 s(approximately 4.8×10^(−2)μGy/h),and ^(133)Ba in 4.05 s and 5.99 s(approximately 3.4×10^(−2)μGy/h)under low and natural background radiation,respectively,with a miss rate below 0.01%.This demonstrates the effectiveness of the proposed approach for fast radionuclides identification,even at low activity levels and highlights its potential for enhancing public safety in diverse radiation environments.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB34020200)National Key Research and Development Program(MOST 2022YFA1602304)+1 种基金Scientific Research Instrument and Equipment Development Program of the Chinese Academy of Sciences(No.GJJSTD20210007)National Natural Science Foundation of China(Nos.12175156,U1632142).
文摘Highly oriented pyrolytic graphite (HOPG) is frequently adopted as the reaction target in12C+12C fusion reaction experiments owing to its superior purity.In this study,we investigate the reaction yield dependence on the accumulated beam dose on HOPG target using a novel detection system consisting of a time-projection chamber and silicon array.The reaction yields are significantly reduced under intense beam bombardment owing to radiation damage to the HOPG surface.The α_(0) and p_(0,1) yields decrease by 51.5% and 25%,respectively,when the ^(12)C^(2+) beam dose accumulates at 5 C.Using the novel detection system and HOPG target,the α0yield is determined to be 2.68_(-1.69)^(+4.69)×10^(-17/12) C after correcting for the yield loss due to radiation damage.Our result represents the highest sensitivity achieved to date in direct measurements of ^(12)C(12C,α_(0))^(20)Ne.
文摘Background:Over the past few decades,a threefold increase in obesity and type 2 diabetes(T2D)has placed a heavy burden on the health-care system and society.Previous studies have shown correlations between obesity,T2D,and neurodegenera-tive diseases,including dementia.It is imperative to further understand the relation-ship between obesity,T2D,and cognitive deficits.Methods:This investigation tested and evaluated the cognitive impact of obesity and T2D induced by high-fat diet(HFD)and the effect of the host genetic background on the severity of cognitive decline caused by obesity and T2D in collaborative cross(CC)mice.The CC mice are a genetically diverse panel derived from eight inbred strains.Results:Our findings demonstrated significant variations in the recorded phenotypes across different CC lines compared to the reference mouse line,C57BL/6J.CC037 line exhibited a substantial increase in body weight on HFD,whereas line CC005 ex-hibited differing responses based on sex.Glucose tolerance tests revealed significant variations,with some lines like CC005 showing a marked increase in area under the curve(AUC)values on HFD.Organ weights,including brain,spleen,liver,and kidney,varied significantly among the lines and sexes in response to HFD.Behavioral tests using the Morris water maze indicated that cognitive performance was differentially affected by diet and genetic background.Conclusions:Our study establishes a foundation for future quantitative trait loci map-ping using CC lines and identifying genes underlying the comorbidity of Alzheimer's disease(AD),caused by obesity and T2D.The genetic components may offer new tools for early prediction and prevention.
基金sponsored by the National Natural Science Foundation of China[grant number U2442218]。
文摘Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimilation is quite challenging.This is because there is limited knowledge about the cross-component background error covariance(BEC)between LST and atmospheric state variables.This study aims to clarify whether there is a relationship between the error of LST and atmospheric variables,and whether this relationship varies spatially and temporally.To this end,the BEC coupled with atmospheric variables and LST was constructed(LST-BEC),and its characteristics were analyzed based on the 2023 mei-yu season.The general characteristics of LST-BEC show that the LST is mainly correlated with the atmospheric temperature and the correlation decreases gradually with a rise in atmospheric height,and the error standard deviation of the LST is noticeably larger than that of the low-level atmospheric temperature.The spatiotemporal characteristics of LST-BEC on the heavy-rain day and light-rain day show that the error correlation and error standard deviation of LST and low-level atmospheric temperature and humidity are closely related to the weather background,and also have obvious diurnal variations.These results provide valuable information for strongly coupled land-atmosphere assimilation.
基金supported by the National Natural Science Foundation of China(Nos.61906168,62202429 and 62272267)the Zhejiang Provincial Natural Science Foundation of China(No.LY23F020023)the Construction of Hubei Provincial Key Laboratory for Intelligent Visual Monitoring of Hydropower Projects(No.2022SDSJ01)。
文摘Accurately identifying building distribution from remote sensing images with complex background information is challenging.The emergence of diffusion models has prompted the innovative idea of employing the reverse denoising process to distill building distribution from these complex backgrounds.Building on this concept,we propose a novel framework,building extraction diffusion model(BEDiff),which meticulously refines the extraction of building footprints from remote sensing images in a stepwise fashion.Our approach begins with the design of booster guidance,a mechanism that extracts structural and semantic features from remote sensing images to serve as priors,thereby providing targeted guidance for the diffusion process.Additionally,we introduce a cross-feature fusion module(CFM)that bridges the semantic gap between different types of features,facilitating the integration of the attributes extracted by booster guidance into the diffusion process more effectively.Our proposed BEDiff marks the first application of diffusion models to the task of building extraction.Empirical evidence from extensive experiments on the Beijing building dataset demonstrates the superior performance of BEDiff,affirming its effectiveness and potential for enhancing the accuracy of building extraction in complex urban landscapes.
基金supported by the Ministry of Science and Technology of China(No.2022YFF0802501)Inner Mongolia Autonomous Region Science and Technology Program(Nos.2021GG0100 and 2022YFHH0116).
文摘Generally speaking,the precursors of ozone(O_(3)),nitrogen oxides and volatile organic compounds are very low in desert areas due to the lack of anthropogenic emissions and natural emissions,and thus O_(3)concentrations are relatively low.However,high summer background concentrations of about 100μg/m^(3)or 60 ppb were found in the Alxa Desert in the highland of northwest China based on continuous summer observations from 2019 to 2021,which was higher than the most of natural background areas or clean areas in world for summer O_(3)background concentrations.The high O_(3)background concentrations were related to surface features and altitude.Heavy-intensity anthropogenic activity areas in desert areas can cause increased O_(3)concentrations or pollution,but also generated O_(3)depleting substances such as nitrous oxide,which eventually reduced the regional O_(3)baseline values.Nitrogen dioxide(NO2)also had a dual effect on O_(3)generation,showing promotion at low concentrations and inhibition at high concentrations.In addition,sand-dust weather reduced O_(3)clearly,but O_(3)eventually stabilized around the background concentration values and did not vary with sand-dust particulate matter.
基金supported by the National Natural Science Foundation of China(Grant Nos.42150204 and 2288101)supported by the China National Postdoctoral Program for Innovative Talents(BX20230045)the China Postdoctoral Science Foundation(2023M730279)。
文摘A nonlinear multi-scale interaction(NMI)model was proposed and developed by the first author for nearly 30 years to represent the evolution of atmospheric blocking.In this review paper,we first review the creation and development of the NMI model and then emphasize that the NMI model represents a new tool for identifying the basic physics of how climate change influences mid-to-high latitude weather extremes.The building of the NMI model took place over three main periods.In the 1990s,a nonlinear Schr?dinger(NLS)equation model was presented to describe atmospheric blocking as a wave packet;however,it could not depict the lifetime(10-20 days)of atmospheric blocking.In the 2000s,we proposed an NMI model of atmospheric blocking in a uniform basic flow by making a scale-separation assumption and deriving an eddyforced NLS equation.This model succeeded in describing the life cycle of atmospheric blocking.In the 2020s,the NMI model was extended to include the impact of a changing climate mainly by altering the basic zonal winds and the magnitude of the meridional background potential vorticity gradient(PVy).Model results show that when PVy is smaller,blocking has a weaker dispersion and a stronger nonlinearity,so blocking can be more persistent and have a larger zonal scale and weaker eastward movement,thus favoring stronger weather extremes.However,when PVy is much smaller and below a critical threshold under much stronger winter Arctic warming of global warming,atmospheric blocking becomes locally less persistent and shows a much stronger westward movement,which acts to inhibit local cold extremes.Such a case does not happen in summer under global warming because PVy fails to fall below the critical threshold.Thus,our theory indicates that global warming can render summer-blocking anticyclones and mid-to-high latitude heatwaves more persistent,intense,and widespread.
文摘BACKGROUND Inadequate glycemic control in patients with type 2 diabetes(T2DM)is a major public health problem and a significant risk factor for the progression of diabetic complications.AIM To evaluate the effects of intensive and supportive glycemic management strategies over a 12-month period in individuals with T2DM with glycated hemoglobin(HbA1c)≥10%and varying backgrounds of glycemic control.METHODS This prospective observational study investigated glycemic control in patients with poorly controlled T2DM over 12 months.Participants were categorized into four groups based on prior glycemic history:Newly diagnosed,previously well controlled with recent worsening,previously off-target but now worsening,and HbA1c consistently above 10%.HbA1c levels were monitored quarterly,and patients received medical,educational,and dietary support as needed.The analysis focused on the success rates of good glycemic control and the associated factors within each group.RESULTS The study showed significant improvements in HbA1c levels in all participants.The most significant improvement was observed in individuals newly diagnosed with diabetes:65%achieved an HbA1c target of≤7%.The results varied between participants with different glycemic control histories,followed by decreasing success rates:39%in participants with previously good glycemic control,21%in participants whose glycemic control had deteriorated compared to before,and only 10%in participants with persistently poor control,with mean HbA1c levels of 6.3%,7.7%,8.2%,and 9.7%,respectively.After one year,65.2%of the“newly diagnosed patients”,39.3%in the“previously controlled group”,21.9%in the“previously off-target but now worsened'”group and 10%in the“poorly controlled from the start”group had achieved HbA1c levels of 7 and below.CONCLUSION In poorly controlled diabetes,the rate at which treatment goals are achieved is associated with the glycemic background characteristics,emphasizing the need for tailored strategies.Therefore,different and comprehensive treatment approaches are needed for patients with persistent uncontrolled diabetes.
文摘INTRODUCTION WITH HISTORICAL AND DIPLOMATIC BACKGROUND.Situated at the southern part of the Adriatic coast,Montenegro is a small country in size but is gaining importance in international economic and geopolitical affairs.Over the past decade,it has found itself balancing between the East and the West-aspiring to join the European Union(EU),while staying open to global partnerships,particularly with China.
基金supported by the National Natural Science Foundation of China(NSFC,grant Nos.12173100,11973097 and 12022302)the Youth Innovation Promotion Association CAS(Nos.2021317 and Y2021087)+1 种基金the Scientific Instrument Developing Project of the CAS(No.20200077)the Strategic Priority Research Program on Space Science,Chinese Academy of Sciences(No.XDA 15320104).
文摘The Hard X-ray Imager(HXI)payload,a component of China’s Advanced Space-based Solar Observatory satellite,is designed to observe solar X-ray emissions in the 30-200 keV range,with the aim of investigating nonthermal physical processes during solar flares.Before launch,Geant4 simulations were employed to assess the onorbit background of the HXI instrument,evaluating its performance and potential to achieve its scientific objectives.This study addresses issues identified in previous simulations and conducts further analyses to examine the distribution of background counts across the 99 detectors.The results demonstrate alignment between simulations and observations at low and medium geomagnetic latitudes;however,challenges persist at high geomagnetic latitudes due to limitations in the current albedo photon model.This investigation provides insights into background sources from various particles,enhances understanding of space background characteristics,and offers guidance for background subtraction in imaging processes.
基金Funding was provided by the CNRS,La Rochelle Université,the LPO,the Agence de l’Eau Adour-Garonne,the Conseil Départemental de la Charente-Maritime,the ANR PAMPAS(ANR-18-CE32-0006)the Beauval Nature association,the Contrat de plan Etat-région Econat and the Région Nouvelle Aquitaine(Projet d’Observatoire du Marais de Brouage-PSGAR CRNA 2025).
文摘Animal species exhibit a wide range of coloration and patterns,which are under strong selection and often linked to individual quality,influencing mate choice,recognition,signaling,and interspecific interactions such as predator avoidance.In amphibians,coloration can vary based on individual traits as well as environmental conditions,including the coloration of their environment.In this study,we described the dorsal coloration(body coloration reticulated by dark patches)in 676 Western spadefoot toads(Pelobates cultripes)from the French Atlantic coast,comparing color variations across different substrates.In addition,we assessed color change in 18 toads transferred between bright and dark substrates.We demonstrated that the dorsal coloration varies based on capture locations(beach vs.inland)and associated substrate types(bright vs.dark),suggesting background color matching.We showed more pronounced effects in females,which might reflect varying predation risks.Experimentally,we showed that individuals can rapidly adjust their coloration to match the substrate within 24 h.Rapid color changes in response to substrate type indicate significant pigmentation plasticity.Bright individuals from sandy substrates showed less dorsal background(body)color change than dark inland individuals,while patch coloration responded differently depending on the substrate of origin.These findings highlight the complex interactions between substrate type,sex,and pigmentation plasticity.These interactions have potential costs and benefits,which might be linked to melanin production,which warrant further investigation.
文摘Author:Hu Yan.This book provides a comprehensive overview of the background,causes,process,and impact of the British invasion of Xizang from 1903 to 1904,offering an in-depth analysis of the nature and detrimental actions of imperialist aggression.
文摘The turbine blades operate under high temperature and high pressure conditions,and when using radiation thermometry,the influence of radiation from surrounding blades leads to measurement errors.To address this issue,this paper develops a three-dimensional discretized dynamic radiation transfer model based on the blade shape of the turbine.The relationship between the radiation angle coefficient of the surrounding blades and the rotation angle of the blade under test is analyzed.The radiation angle coefficient is calculated using the triangular element method,and temperature inversion is performed based on the effective emissivity to compute the measurement error.The results show that under dynamic high temperature conditions,the temperature measurement error caused by reflection at the selected 60%leaf height point varies with the rotation angle,and the maximum reaches 25.58K.The angular coefficient exhibits periodic fluctuations with changes in rotation angle,and the maximum effective emissivity increases as the rotation angle increases.As the blade height increases,the impact of reflected radiation on radiometric temperature measurement errors shows a decreasing trend.This study provides a reference for radiation thermometry in dynamic high-temperature environments.
基金Supported by the National Key R&D Program of China(Nos.2022YFA1602301,2022YFA1603300,and 2023YFA1606701)National Natural Science Foundation of China(Nos.U1867211,12275026,and 12222514)the CAS Light of West China Program grant No.2020-82。
文摘The precise determination of cross sections for key nuclear reactions within the Gamow window is crucial for advancing the study of stellar evolution and nucleosynthesis.However,extremely low reaction yields combined with the cosmic-ray-induced background make these measurements highly challenging,particularly for capture reactions.This work demonstrates the second configuration of the large-scale modular BGO detection array(LAMBDA-Ⅱ)designed to capture reaction measurements and introduces a method for suppressingγ-ray detection background in ground laboratories.By employing active and passive shielding,the background of LAMBDA-Ⅱwas significantly reduced by approximately two orders of magnitude,reaching 8.1×10^(-3)and 1.0×10^(-3)keV^(-1)h^(-1)in the 6-11 and 11-20 MeV energy ranges,respectively.When combined with a mA-scale intensity beam,this reduced background enables the investigation of several capture reactions of astrophysical interest in ground laboratories.
文摘The Newtonian gravitational constant G is one of the most important fundamental constants of nature, but still remains resistant to the standard model of physics and disconnected from quantum theory. During the past >100 years, hundreds of G values have been measured to be ranging around 6.66 to 6.7559 × 10−11 m3·kg−1·s−2 using macroscopic masses. More recently, however, a G value ((6.04 ± 0.06) × 10−11 m3·kg−1·s−2) measured using millimetre-sized masses shows significant deviation (by ~9%) from the reference G value, which the authors explained is resulted from “the known systematic uncertainties”. However, based on the observation of historical G values and the protocol of the millimetre-sized masses based experiment, here we proposed a theory that this deviation is not from “systematic uncertainties” but actually G will rapidly decrease when masses sphere diameter is less than 0.02 metres. Moreover, this theory predicted the G value will be 5.96 × 10−11 m3·kg−1·s−2 between masses whose diameter are 2 millimetres (0.002 metres), which matches the measured G value very well.
文摘Objective:Lanqin oral liquid(LOL),as a traditional Chinese medicine prescription,has obvious clinical efficacy in the treatment of pharyngeal inflammation.Exploring the distribution of LOL prototype components and metabolites in plasma is of great significance for understanding potentially effective compounds.The aim of this study is to elucidate the metabolites and main metabolic pathways of LQL in vivo.Methods:In this study,a reliable approach integrated background subtraction and mass defect filtering(MDF),based on quadrupole time-of-flight mass spectrometry(QTOF-MS)technology,was performed to systematically scan the metabolites of LOL in rat plasma.In addition,according to the prototype mass spectrometry fragmentation pattern and combined with metabolic pathway analysis,a biotransformation oriented analysis strategy was established and applied to the identification of metabolites in LOL in vivo.Results:As a result,159 compounds(58 prototypes and 101 metabolites)were identified or tentatively characterized in drug-containing plasma,including 74 flavonoids,30 alkaloids,34 terpenoids,five phenylpropanoids,six phenolic acids,five fatty acids,and five other type components.The main metabolic pathways include methylation,demethylation,hydroxylation,hydrogenation,glucuronidation,and sulfation.Conclusions:This study provides an overall characterization of the metabolites of LOL in vivo for the first time,providing a solid material basis for exploring the therapeutic effects and pharmacological mechanisms of LOL.
基金supported by the National Key Research and Development Programs of China(2024YFF1000100 and 2021YFD1301102)the National Natural Science Foundation of China (32172702)+3 种基金the State Key Laboratory of Animal Biotech Breeding (XQSWYZQZ-KFYX-4)Zaozhuang Elite Industrial Innovation ProgramAgricultural Science and Technology Innovation Program (ASTIP-IAS-TS-6)supported by the United States National Science Foundation (NSF) Collaborative Research Grant (DBI-1458515)
文摘The quantitative trait loci(QTL)-by-environment(Q × E) interaction effect is hard to detect because there are no effective ways to control the genomic background. In this study, we propose a linear mixed model that simultaneously analyzes data from multiple environments to detect Q × E interactions. This model incorporates two different kinship matrices derived from the genome-wide markers to control both main and interaction polygenic background effects. Simulation studies demonstrate that our approach is more powerful than the meta-analysis and inclusive composite interval mapping methods. We further analyze four agronomic traits of rice across four environments. A main effect QTL is identified for 1000-grain weight(KGW), while no QTL are found for tiller number. Additionally, a large QTL with a significant Q × E interaction is detected on chromosome 7 affecting grain number, yield, and KGW. This region harbors two important genes, PROG1 and Ghd7. Furthermore, we apply our mixed model to analyze lodging in barley across six environments. The six regions exhibiting Q × E interaction effects identified by our approach overlap with the SNPs previously identified using EM and MCMC-based Bayesian methods, further validating the robustness of our approach. Both simulation studies and empirical data analyses show that our method outperforms all other methods compared.
