Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and ma...Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and magnetic field enhanced-electrochemical activity remains to be fully elucidated.Herein,single-domain CoFe_(2)O_(4) catalysts with tunable oxygen vacancies(CFO-V_(O)) were synthesized to probe how V_(O) mediates magnetism and OER activity under magnetic field.The introduction of V_(O) can simultaneously modulate saturation magnetization(M_(s)) and coercivity(H_(c)),where the increased M_(s) dominates the magnetic field-enhanced OER activity.Under a 14,000 G magnetic field,the optimized CFO-V_(O) exhibits up to 16.1 % reduction in overpotential and 365 % enhancement in magnetocurrent(MC).Electrochemical analyses and post-OER characterization reveal that the magnetic field synergistically improves OER kinetics through lattice distortion induction,magnetohydrodynamic effect,and spin charge transfer effect.Importantly,the magnetic field promotes additional Co^(3+) generation to compensate for charge imbalance caused by V_(O) filling,maintaining dynamic equilibrium of V_(O) and effective reactant adsorption-conversion processes.This work unveils the synergistic mechanism of V_(O) and magnetic parameters for enhancing OER performance under the magnetic field,providing new insights into the design of high-efficiency spinregulated OER catalysts.展开更多
The development of gas condensate reservoirs with a large gas cap,thin oil rim,strong bottom water,and natural barriers faces numerous challenges,including reservoir heterogeneity,coning effects,phase changes,and mult...The development of gas condensate reservoirs with a large gas cap,thin oil rim,strong bottom water,and natural barriers faces numerous challenges,including reservoir heterogeneity,coning effects,phase changes,and multiphase flow dynamics.The influx of gas and water may lead to a low recovery of the oil rim,while reservoir heterogeneity and natural barriers further exacerbate the uneven distribution of reservoir fluid,complicating development strategies.This paper aims to investigate innovative and effective development strategies for this type of reservoir.A detailed,proportionally scaled numerical simulation is performed based on the experimental results of an artificial sand-filled model,providing novel insights into the dynamic behavior of these reservoirs.By understanding the phase behavior and fluid flow characteristics of the reservoir,the study simulates various strategies for the rational and efficient development of the gas condensate reservoir.These strategies include well patterns and completions,the decision to develop the oil rim or gas cap,depletion rates,the bottom water control,and gas injection.The results show that horizontal wells or highly deviated wells are more suitable for the development of the oil rim,as they provide larger control ranges.The presence of strong bottom water is advantageous for displacement energy supply and pressure maintenance,but it intensifies water coning effects,leading to an earlier breakthrough and a sharp production decline.Therefore,it is preferable to apply highly deviated wells at the oil-gas contact,developing the oil rim at lower rates and smaller pressure gradients,followed by developing the gas cap.This approach can reduce water coning effects and improve recovery,with oil and gas recovery reaching 24.4%and 67.95%,respectively,which is an increase of 16.74%and 17.84%compared to direct depletion development of the gas cap.Due to the strong water bottom,continuous gas injection at the top of the reservoir becomes challenging.This study introduces gas assisted gravity drainage with water control technology,a novel and highly effective approach that addresses the impact of bottom water coning effects on the oil and gas zones and overcomes the limitations of gas flooding in reservoirs with strong bottom water.This method can significantly improve oil and gas recovery,achieving recovery of 39.74%and 84.50%,respectively.Compared to the conventional depletion strategy of sequential oil rim and gas cap development,this method achieves additional improvements of 15.33%and 16.55%in oil and gas recovery,respectively.展开更多
In this paper,the convergence of the split-step theta method for stochastic differential equations is analyzed using stochastic C-stability and stochastic B-consistency.The fact that the numerical scheme,which is both...In this paper,the convergence of the split-step theta method for stochastic differential equations is analyzed using stochastic C-stability and stochastic B-consistency.The fact that the numerical scheme,which is both stochastically C-stable and stochastically B-consistent,is convergent has been proved in a previous paper.In order to analyze the convergence of the split-step theta method(θ∈[1/2,1]),the stochastic C-stability and stochastic B-consistency under the condition of global monotonicity have been researched,and the rate of convergence 1/2 has been explored in this paper.It can be seen that the convergence does not require the drift function should satisfy the linear growth condition whenθ=1/2 Furthermore,the rate of the convergence of the split-step scheme for stochastic differential equations with additive noise has been researched and found to be 1.Finally,an example is given to illustrate the convergence with the theoretical results.展开更多
There are limited quantitative studies on condensate gas using microfluidics under high-pressure and high-temperature conditions.This study employed microfluidics chips based on real porous media structures to conduct...There are limited quantitative studies on condensate gas using microfluidics under high-pressure and high-temperature conditions.This study employed microfluidics chips based on real porous media structures to conduct constant volume depletion experiments and investigate the microscopic mechanisms of condensate gas recovery.The aim of the experiments was to reveal the phase-behavior differences between bulk-phase gas and gas contained in porous media.The results revealed that condensate oil recovery in microfluidics experiments was higher than that in PVT cell tests,and nonuniform condensation and evaporation were exclusively observed in the microfluidics experiments.Furthermore,lower pore connectivity resulted in higher depletion recovery,while more developed fractures led to reduced recovery.Specifically,the chip with fewer fractures achieved the highest recovery(71.15%),whereas the highly fractured chip exhibited the lowest recovery(56.11%).These findings demonstrate that oil saturation during the process of constant volume depletion(CVD)of gas condensate within porous media is lower than that observed in the PVT cell,thus providing experimental evidence for optimizing condensate gas development in field applications.展开更多
In recent years,Mendelian randomization(MR)has been increasingly utilized,leveraging genetic variants as instrumental variables.This approach significantly mitigates confounder effects and reverse causation,precisely ...In recent years,Mendelian randomization(MR)has been increasingly utilized,leveraging genetic variants as instrumental variables.This approach significantly mitigates confounder effects and reverse causation,precisely clarifying the causal links between exposures and outcomes.MR’s unique advantages have made it instrumental in medicine,especially in elucidating glaucoma’s etiology.It facilitates the identification of potential risk factors,laying the groundwork for developing preventative and therapeutic strategies against glaucoma.Recent MR research has delved into diverse potential glaucoma risk factors,including behavioral habits,metabolic profiles,and their causative linkage to the disease.This review encapsulates MR’s analysis in glaucoma etiology,heralding new avenues for understanding underlying mechanisms and establishing causality.展开更多
Volatile sulfur compounds(VSCs)are major contributors to odor pollution and acid rain formation,making accurate monitoring of atmospheric VSCs levels essential for controlling anthropogenic emissions.In this study,we ...Volatile sulfur compounds(VSCs)are major contributors to odor pollution and acid rain formation,making accurate monitoring of atmospheric VSCs levels essential for controlling anthropogenic emissions.In this study,we developed a method for the enrichment and quantification of trace VSCs in actual gas using MIL-53(Al)as preconcentration adsorbent coupled with gas chromatography(GC).We investigated and optimized several factors affecting the efficiency of the method,including adsorbent amount,adsorption temperature,sampling volume,gas flow rate,and desorption temperature.Under optimal experimental conditions,the method demonstrated good linearity in the range of 0.10–26.67 nmol/mol(R^(2)≥0.9968),with low detection limits ranging from 0.03 to 0.11 nmol/mol for ten VSCs.The established method was successfully applied to the enrichment and detection of trace VSCs in four complex actual gas samples,achieving satisfactory recoveries between 82.7%and 109.3%,and good precision with relative standard deviations(RSDs)≤7.12%.This study presents a simple and effective approach for the simultaneous detection of VSCs,offering great potential for VSCs monitoring.展开更多
Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling...Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling”paths usually suffer from either low injectivity or poor gelation control.Herein,we for the first time developed an in-situ high-pressure CO_(2)-triggered gel system based on a smart surfactant,N-erucamidopropyl-N,N-dimethylamine(UC22AMPM),which was introduced into the aqueous slugs to control gas channeling inWAG processes.The water-like,low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO_(2) owing to the formation of wormlike micelles(WLMs),as well as their growth and shear-induced structure buildup under shear flow.The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating,and can be impaired via pressurization above the critical pressure of CO_(2) because of its soaring solvent power.Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre-or post-injected CO_(2) slugs under shear flow,thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode.This smart surfactant enabled high injectivity and satisfactory gelation control,attributable to low initial viscosity and the combined properties of one component and CO_(2)-triggered gelation,respectively.This work could provide a guide towards designing gels for reducing CO_(2) spillover and reinforcing the CO_(2) sequestration effect during CO_(2) enhanced oil recovery processes.展开更多
By means of experiments of C02 miscibility with crude oil, four nonpolar chemicals were evaluated in order to enhance the miscibility of C02 with crude oil. Through pre-slug injection and joint injection of toluene in...By means of experiments of C02 miscibility with crude oil, four nonpolar chemicals were evaluated in order to enhance the miscibility of C02 with crude oil. Through pre-slug injection and joint injection of toluene in CO2, crude oil displacement experiments in the slim-tube were conducted to investigate effects of the toluene- enhanced C02 flooding under simulated subterranean reservoir conditions. Experimental results showed that toluene can enhance extraction of oil into C02 and dissolution of C02 into oil with the increment of 251% and 64% respectively. Addition of toluene can obviously improve the oil recovery in either pre-slug injection or joint injection, and the crude oil recovery increased with the increase of the toluene concentration. The oil recov- ery can increase by 22.5% in pre-slug injection with the high toluene concentration. Pre-slug injection was recom- mended because it can consume less toluene than joint injection. This work could be useful to development and application of the CO） flooding in the oil recoverv as well as CO2 emission reduction.展开更多
Authentication is a key component of quality control,and the quality of Chinese medicinal materials directly impacts clinical efficacy.Chinese medicinal quality control is an important concern of the wider community,a...Authentication is a key component of quality control,and the quality of Chinese medicinal materials directly impacts clinical efficacy.Chinese medicinal quality control is an important concern of the wider community,and it is intricately connected to the future and development of Chinese medicine.Macroscopic identification has been used for thousands of years in Chinese medicine,and it continues to be effective for resolving important issues related to quality control in the modern-day.However,new challenges have emerged for macroscopic identification.For example,new botanical varieties have emerged,with differences in macroscopic features related to cultivated vs.wild materials.Changes in processing methods and cultivation techniques also affect these features.Consequently,continual progress and innovation in Chinese medicinal authentication methods are needed.Macroscopic identification is based on organoleptic assessment,microscopy,and research of ancient texts,such as the Bencao.In addition to collecting information from traditional experience-based differentiation,innovation can take advantage of new technologies that can provide even more detailed,precise information about morphology.In the present review,we summarized inheritance and innovation in the scientific exposition of Chinese medicinal authentication,featuring a review of specialized publications,description of the establishment of a Chinese medicine specimen center and Chinese Medicine digital project,the expansion of authentication technologies,and the formation of a cultural project dedicated to the Compendium of Materia Medica.展开更多
Flue gas fooding is one of the important technologies to improve oil recovery and achieve greenhouse gas storage.In order to study multicomponent fue gas storage capacity and enhanced oil recovery(EOR)performance of f...Flue gas fooding is one of the important technologies to improve oil recovery and achieve greenhouse gas storage.In order to study multicomponent fue gas storage capacity and enhanced oil recovery(EOR)performance of fue gas water-alternating gas(fue gas-WAG)injection after continuous waterfooding in an oil reservoir,a long core fooding system was built.The experimental results showed that the oil recovery factor of fue gas-WAG fooding was increased by 21.25%after continuous waterfooding and fue gas-WAG fooding could further enhance oil recovery and reduce water cut signifcantly.A novel material balance model based on storage mechanism was developed to estimate the multicomponent fue gas storage capacity and storage capacity of each component of fue gas in reservoir oil,water and as free gas in the post-waterfooding reservoir.The ultimate storage ratio of fue gas is 16%in the fue gas-WAG fooding process.The calculation results of fue gas storage capacity showed that the injection gas storage capacity mainly consists of N_(2) and CO_(2),only N_(2) exists as free gas phase in cores,and other components of injection gas are dissolved in oil and water.Finally,injection strategies from three perspectives for fue gas storage,EOR,and combination of fue gas storage and EOR were proposed,respectively.展开更多
Herein,we report bifunctional molybdenum-doped nickel sulfide on nickel foam(Mo-NiS_(x)/NF)for magnetic field-enhanced overall water splitting under alkaline conditions.Proper doping of Mo can lead to optimization of ...Herein,we report bifunctional molybdenum-doped nickel sulfide on nickel foam(Mo-NiS_(x)/NF)for magnetic field-enhanced overall water splitting under alkaline conditions.Proper doping of Mo can lead to optimization of the electronic structure of NiS_(x),which accelerates the dissociation of H2O and the adsorption of OH−in the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)processes,respectively.In addition,the magnetically active Mo-NiS_(x)/NF can further enhance the HER and OER activity under an applied magnetic field due to the magnetoresistance effect and the ferromagnetic(FM)exchange-field penetration effect.As a result,Mo-NiS_(x)/NF requires low overpotentials of 307 mV at 50mA cm^(−2)(for OER)and 136 mV at 10mA cm^(−2)(for HER)under a magnetic field of 10000 G.Furthermore,the electrolytic cell constructed by the bifunctional Mo-NiS_(x)/NFs as both the cathode and the anode shows a low cell voltage of 1.594 V at 10 mA cm^(−2)with optimal stability over 60 h under the magnetic field.Simultaneous enhancement of the HER and OER processes by an external magnetic field through rational design of electrocatalysts might be promising for overall water splitting applications.展开更多
In the past two decades, software aging has been studied by both academic and industry communities. Many scholars focused on analytical methods or time series to model software aging process. While machine learning ha...In the past two decades, software aging has been studied by both academic and industry communities. Many scholars focused on analytical methods or time series to model software aging process. While machine learning has been shown as a very promising technique in application to forecast software state: normal or aging. In this paper, we proposed a method which can give practice guide to forecast software aging using machine learning algorithm. Firstly, we collected data from a running commercial web server and preprocessed these data. Secondly, feature selection algorithm was applied to find a subset of model parameters set. Thirdly, time series model was used to predict values of selected parameters in advance. Fourthly, some machine learning algorithms were used to model software aging process and to predict software aging. Fifthly, we used sensitivity analysis to analyze how heavily outcomes changed following input variables change. In the last, we applied our method to an IIS web server. Through analysis of the experiment results, we find that our proposed method can predict software aging in the early stage of system development life cycle.展开更多
The study of vehicular networks has attracted considerable interest in academia and the industry.In the broad area,connected vehicles and autonomous driving are technologies based on wireless data communication betwee...The study of vehicular networks has attracted considerable interest in academia and the industry.In the broad area,connected vehicles and autonomous driving are technologies based on wireless data communication between vehicles or between vehicles and infrastructures.A Vehicle-to-Infrastructure(V2I)system consists of communications and computing over vehicles and related infrastructures.In such a system,wireless sensors are installed in some selected points along roads or driving areas.In autonomous driving,it is crucial for a vehicle to figure out the ideal routes by the communications between its equipped sensors and infrastructures then the vehicle is automatically moving along the routes.In this paper,we propose a Bezier curve based recursive algorithm,which effectively creates routes for vehicles through the communication between the On-Board Unit(OBU)and the Road-Side Units(RSUs).In addition,this approach generates a very low overhead.We conduct simulations to test the proposed algorithm in various situations.The experiment results demonstrate that our algorithm creates almost ideal routes.展开更多
An automated spectral classification technique for large sky surveys is proposed. We firstly perform spectral line matching to determine redshift candidates for an observed spectrum, and then estimate the spectral cla...An automated spectral classification technique for large sky surveys is proposed. We firstly perform spectral line matching to determine redshift candidates for an observed spectrum, and then estimate the spectral class by measuring the similarity between the observed spectrum and the shifted templates for each redshift candidate. As a byproduct of this approach, the spectral redshift can also be obtained with high accuracy. Compared with some approaches based on computerized learning methods in the literature, the proposed approach needs no training, which is time-consuming and sensitive to selection of the training set. Both simulated data and observed spectra are used to test the approach; the results show that the proposed method is efficient, and it can achieve a correct classification rate as high as 92.9%, 97.9% and 98.8% for stars, galaxies and quasars, respectively.展开更多
Internet of Vehicles(henceforth called IoV) is a public network system and high-value target for intrusions that may cause efficiency issues, privacy leakages or even physical damage. Conventional intrusion detection ...Internet of Vehicles(henceforth called IoV) is a public network system and high-value target for intrusions that may cause efficiency issues, privacy leakages or even physical damage. Conventional intrusion detection methods are normally designed for the Internet infrastructures which cannot directly apply in the context of IoV. This work proposes an FPGA based intrusion detection method that can not only achieve real-time scanning performance but also be applied in vehicular environment. We evaluate our scheme on a Xilinx FPGA based platform. Experiments show that the proposed system can achieve a throughput of more than 39 Gbps on existing FPGA platform which is about 15% higher than state-of-the-art techniques,and the total power consumption for the prototype is about 7.5 w. Moreover, the processing latency of the prototype is about 4 us and is about one sixtieth part of the popular software IDS systems.展开更多
BACKGROUND Tardive dyskinesia(TD)is a serious and disabling movement disorder;it impairs social function and quality of life and increases the mortality rate.TD is usually induced by the use of antipsychotic drugs;how...BACKGROUND Tardive dyskinesia(TD)is a serious and disabling movement disorder;it impairs social function and quality of life and increases the mortality rate.TD is usually induced by the use of antipsychotic drugs;however,the underlying mechanism remains unclear.Pharmacotherapy of TD includes cholinergic drugs,benzodiazepines,ginkgo biloba extract(GBE),antioxidants,amantadine,propanolol,botulinum toxin,valbenazine,and deutetrabenazine,whereas the non-pharmacotherapy approach includes modified electroconvulsive therapy(MECT)and deep brain stimulation.We successfully treated a chronic schizophrenia patient with comorbid long-term severe TD using deutetrabenazine,clozapine,and MECT.CASE SUMMARY A 69-year-old woman who was diagnosed as having schizophrenia 16 years ago developed severe TD after 6-mo prescription of risperidone oral solution.Her TD symptoms did not resolve despite various treatments,such as GBE,vitamin E,trihexyphenidyl,promethazine,benzodiazepines,and switching to quetiapine and olanzapine.After admission,she was given deutetrabenazine 6 mg bid.Her buccal tremor was slightly resolved 3 d later;however,her tongue remained protruded and could not be retracted.Quetiapine was switched to clozapine on day 4,and the buccal tremor remarkably resolved,and the tongue could be retracted into the mouth from day 6 onward.After three sessions of MECT,the buccal tremor resolved further.Since then,she has been able to take a semifluid diet,and her quality of life improved remarkably during 6 mo of follow-up.CONCLUSION TD is a serious condition which could be caused by antipsychotic medications;however,the best strategy against TD is prevention and monitoring during using antipsychotics.For patients with TD caused by antipsychotic medication use,multiple measures should be considered like switching to clozapine,adjunction with deutetrabenazine,or even MECT.展开更多
Single atom catalysts(SACs)have garnered significant attention in the field of catalysis over the past decade due to their exceptional atom utilization efficiency and distinct physical and chemical properties.For the ...Single atom catalysts(SACs)have garnered significant attention in the field of catalysis over the past decade due to their exceptional atom utilization efficiency and distinct physical and chemical properties.For the semiconductor-based electrical gas sensor,the core is the catalysis process of target gas molecules on the sensitive materials.In this context,the SACs offer great potential for highly sensitive and selective gas sensing,however,only some of the bubbles come to the surface.To facilitate practical applications,we present a comprehensive review of the preparation strategies for SACs,with a focus on overcoming the challenges of aggregation and low loading.Extensive research efforts have been devoted to investigating the gas sensing mechanism,exploring sensitive materials,optimizing device structures,and refining signal post-processing techniques.Finally,the challenges and future perspectives on the SACs based gas sensing are presented.展开更多
基金supported by the “Climbing Plan” of Harbin Normal University (No.XKB202301)National Natural Science Foundation of China (Nos.21871065 and 22071038)。
文摘Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and magnetic field enhanced-electrochemical activity remains to be fully elucidated.Herein,single-domain CoFe_(2)O_(4) catalysts with tunable oxygen vacancies(CFO-V_(O)) were synthesized to probe how V_(O) mediates magnetism and OER activity under magnetic field.The introduction of V_(O) can simultaneously modulate saturation magnetization(M_(s)) and coercivity(H_(c)),where the increased M_(s) dominates the magnetic field-enhanced OER activity.Under a 14,000 G magnetic field,the optimized CFO-V_(O) exhibits up to 16.1 % reduction in overpotential and 365 % enhancement in magnetocurrent(MC).Electrochemical analyses and post-OER characterization reveal that the magnetic field synergistically improves OER kinetics through lattice distortion induction,magnetohydrodynamic effect,and spin charge transfer effect.Importantly,the magnetic field promotes additional Co^(3+) generation to compensate for charge imbalance caused by V_(O) filling,maintaining dynamic equilibrium of V_(O) and effective reactant adsorption-conversion processes.This work unveils the synergistic mechanism of V_(O) and magnetic parameters for enhancing OER performance under the magnetic field,providing new insights into the design of high-efficiency spinregulated OER catalysts.
基金the support from the National Natural Science Foundation of China(NSFC Grant No.:52004032)。
文摘The development of gas condensate reservoirs with a large gas cap,thin oil rim,strong bottom water,and natural barriers faces numerous challenges,including reservoir heterogeneity,coning effects,phase changes,and multiphase flow dynamics.The influx of gas and water may lead to a low recovery of the oil rim,while reservoir heterogeneity and natural barriers further exacerbate the uneven distribution of reservoir fluid,complicating development strategies.This paper aims to investigate innovative and effective development strategies for this type of reservoir.A detailed,proportionally scaled numerical simulation is performed based on the experimental results of an artificial sand-filled model,providing novel insights into the dynamic behavior of these reservoirs.By understanding the phase behavior and fluid flow characteristics of the reservoir,the study simulates various strategies for the rational and efficient development of the gas condensate reservoir.These strategies include well patterns and completions,the decision to develop the oil rim or gas cap,depletion rates,the bottom water control,and gas injection.The results show that horizontal wells or highly deviated wells are more suitable for the development of the oil rim,as they provide larger control ranges.The presence of strong bottom water is advantageous for displacement energy supply and pressure maintenance,but it intensifies water coning effects,leading to an earlier breakthrough and a sharp production decline.Therefore,it is preferable to apply highly deviated wells at the oil-gas contact,developing the oil rim at lower rates and smaller pressure gradients,followed by developing the gas cap.This approach can reduce water coning effects and improve recovery,with oil and gas recovery reaching 24.4%and 67.95%,respectively,which is an increase of 16.74%and 17.84%compared to direct depletion development of the gas cap.Due to the strong water bottom,continuous gas injection at the top of the reservoir becomes challenging.This study introduces gas assisted gravity drainage with water control technology,a novel and highly effective approach that addresses the impact of bottom water coning effects on the oil and gas zones and overcomes the limitations of gas flooding in reservoirs with strong bottom water.This method can significantly improve oil and gas recovery,achieving recovery of 39.74%and 84.50%,respectively.Compared to the conventional depletion strategy of sequential oil rim and gas cap development,this method achieves additional improvements of 15.33%and 16.55%in oil and gas recovery,respectively.
基金Supported by the National Natural Science Foundation of China (Grant No. 12301521)the Natural Science Foundation of Shanxi Province (Grant No. 20210302124081)。
文摘In this paper,the convergence of the split-step theta method for stochastic differential equations is analyzed using stochastic C-stability and stochastic B-consistency.The fact that the numerical scheme,which is both stochastically C-stable and stochastically B-consistent,is convergent has been proved in a previous paper.In order to analyze the convergence of the split-step theta method(θ∈[1/2,1]),the stochastic C-stability and stochastic B-consistency under the condition of global monotonicity have been researched,and the rate of convergence 1/2 has been explored in this paper.It can be seen that the convergence does not require the drift function should satisfy the linear growth condition whenθ=1/2 Furthermore,the rate of the convergence of the split-step scheme for stochastic differential equations with additive noise has been researched and found to be 1.Finally,an example is given to illustrate the convergence with the theoretical results.
基金supported by the National Natural Science Foundation of China(grant number 52404044).
文摘There are limited quantitative studies on condensate gas using microfluidics under high-pressure and high-temperature conditions.This study employed microfluidics chips based on real porous media structures to conduct constant volume depletion experiments and investigate the microscopic mechanisms of condensate gas recovery.The aim of the experiments was to reveal the phase-behavior differences between bulk-phase gas and gas contained in porous media.The results revealed that condensate oil recovery in microfluidics experiments was higher than that in PVT cell tests,and nonuniform condensation and evaporation were exclusively observed in the microfluidics experiments.Furthermore,lower pore connectivity resulted in higher depletion recovery,while more developed fractures led to reduced recovery.Specifically,the chip with fewer fractures achieved the highest recovery(71.15%),whereas the highly fractured chip exhibited the lowest recovery(56.11%).These findings demonstrate that oil saturation during the process of constant volume depletion(CVD)of gas condensate within porous media is lower than that observed in the PVT cell,thus providing experimental evidence for optimizing condensate gas development in field applications.
基金Supported by Shenzhen Science and Technology Program(No.JCYJ20220530152005013,No.JCYJ20230807114605011)Sanming Project of Medicine in Shenzhen(No.SZZYSM202411007).
文摘In recent years,Mendelian randomization(MR)has been increasingly utilized,leveraging genetic variants as instrumental variables.This approach significantly mitigates confounder effects and reverse causation,precisely clarifying the causal links between exposures and outcomes.MR’s unique advantages have made it instrumental in medicine,especially in elucidating glaucoma’s etiology.It facilitates the identification of potential risk factors,laying the groundwork for developing preventative and therapeutic strategies against glaucoma.Recent MR research has delved into diverse potential glaucoma risk factors,including behavioral habits,metabolic profiles,and their causative linkage to the disease.This review encapsulates MR’s analysis in glaucoma etiology,heralding new avenues for understanding underlying mechanisms and establishing causality.
基金financially supported by National Natural Science Foundation of China(22176018)。
文摘Volatile sulfur compounds(VSCs)are major contributors to odor pollution and acid rain formation,making accurate monitoring of atmospheric VSCs levels essential for controlling anthropogenic emissions.In this study,we developed a method for the enrichment and quantification of trace VSCs in actual gas using MIL-53(Al)as preconcentration adsorbent coupled with gas chromatography(GC).We investigated and optimized several factors affecting the efficiency of the method,including adsorbent amount,adsorption temperature,sampling volume,gas flow rate,and desorption temperature.Under optimal experimental conditions,the method demonstrated good linearity in the range of 0.10–26.67 nmol/mol(R^(2)≥0.9968),with low detection limits ranging from 0.03 to 0.11 nmol/mol for ten VSCs.The established method was successfully applied to the enrichment and detection of trace VSCs in four complex actual gas samples,achieving satisfactory recoveries between 82.7%and 109.3%,and good precision with relative standard deviations(RSDs)≤7.12%.This study presents a simple and effective approach for the simultaneous detection of VSCs,offering great potential for VSCs monitoring.
基金Financial support from the Natural Science Foundation of Sichuan Province(2022NSFSC0030)National Natural Science Foundation of China(U1762218)is gratefully acknowledged.
文摘Undesirable gas channeling always occurs along the high-permeability layers in heterogeneous oil reservoirs during water-alternating-CO_(2)(WAG)flooding,and conventional polymer gels used for blocking the“channeling”paths usually suffer from either low injectivity or poor gelation control.Herein,we for the first time developed an in-situ high-pressure CO_(2)-triggered gel system based on a smart surfactant,N-erucamidopropyl-N,N-dimethylamine(UC22AMPM),which was introduced into the aqueous slugs to control gas channeling inWAG processes.The water-like,low-viscosity UC22AMPM brine solution can be thickened by high-pressure CO_(2) owing to the formation of wormlike micelles(WLMs),as well as their growth and shear-induced structure buildup under shear flow.The thickening power can be further potentiated by the generation of denser WLMs resulting from either surfactant concentration augmentation or a certain range of heating,and can be impaired via pressurization above the critical pressure of CO_(2) because of its soaring solvent power.Core flooding tests using heterogeneous cores demonstrated that gas channeling was alleviated by plugging of high-capacity channels due to the in-situ gelation of UC22AMPM slugs upon their reaction with the pre-or post-injected CO_(2) slugs under shear flow,thereupon driving chase fluids into unrecovered low-permeability areas and producing an 8.0% higher oil recovery factor than the conventional WAG mode.This smart surfactant enabled high injectivity and satisfactory gelation control,attributable to low initial viscosity and the combined properties of one component and CO_(2)-triggered gelation,respectively.This work could provide a guide towards designing gels for reducing CO_(2) spillover and reinforcing the CO_(2) sequestration effect during CO_(2) enhanced oil recovery processes.
基金Supported by the National Science&Technology Pillar Program(2012BAC24B03)
文摘By means of experiments of C02 miscibility with crude oil, four nonpolar chemicals were evaluated in order to enhance the miscibility of C02 with crude oil. Through pre-slug injection and joint injection of toluene in CO2, crude oil displacement experiments in the slim-tube were conducted to investigate effects of the toluene- enhanced C02 flooding under simulated subterranean reservoir conditions. Experimental results showed that toluene can enhance extraction of oil into C02 and dissolution of C02 into oil with the increment of 251% and 64% respectively. Addition of toluene can obviously improve the oil recovery in either pre-slug injection or joint injection, and the crude oil recovery increased with the increase of the toluene concentration. The oil recov- ery can increase by 22.5% in pre-slug injection with the high toluene concentration. Pre-slug injection was recom- mended because it can consume less toluene than joint injection. This work could be useful to development and application of the CO） flooding in the oil recoverv as well as CO2 emission reduction.
基金Research Grants Council(Grant No.12103919)of Hong Kong。
文摘Authentication is a key component of quality control,and the quality of Chinese medicinal materials directly impacts clinical efficacy.Chinese medicinal quality control is an important concern of the wider community,and it is intricately connected to the future and development of Chinese medicine.Macroscopic identification has been used for thousands of years in Chinese medicine,and it continues to be effective for resolving important issues related to quality control in the modern-day.However,new challenges have emerged for macroscopic identification.For example,new botanical varieties have emerged,with differences in macroscopic features related to cultivated vs.wild materials.Changes in processing methods and cultivation techniques also affect these features.Consequently,continual progress and innovation in Chinese medicinal authentication methods are needed.Macroscopic identification is based on organoleptic assessment,microscopy,and research of ancient texts,such as the Bencao.In addition to collecting information from traditional experience-based differentiation,innovation can take advantage of new technologies that can provide even more detailed,precise information about morphology.In the present review,we summarized inheritance and innovation in the scientific exposition of Chinese medicinal authentication,featuring a review of specialized publications,description of the establishment of a Chinese medicine specimen center and Chinese Medicine digital project,the expansion of authentication technologies,and the formation of a cultural project dedicated to the Compendium of Materia Medica.
基金This work was supported by the Department of Science and Technology of Sichuan Province(2019YFG0457)the National Natural Science Foundation of China(5183000045)+1 种基金the National Major Science and Technology Project of CNPC"Research and Application of Key Technologies for Beneft Development of Volcanic Rock Reservoirs”(2017E-04-05)the PetroChina Major Science and Technology Project(2018E-1805).
文摘Flue gas fooding is one of the important technologies to improve oil recovery and achieve greenhouse gas storage.In order to study multicomponent fue gas storage capacity and enhanced oil recovery(EOR)performance of fue gas water-alternating gas(fue gas-WAG)injection after continuous waterfooding in an oil reservoir,a long core fooding system was built.The experimental results showed that the oil recovery factor of fue gas-WAG fooding was increased by 21.25%after continuous waterfooding and fue gas-WAG fooding could further enhance oil recovery and reduce water cut signifcantly.A novel material balance model based on storage mechanism was developed to estimate the multicomponent fue gas storage capacity and storage capacity of each component of fue gas in reservoir oil,water and as free gas in the post-waterfooding reservoir.The ultimate storage ratio of fue gas is 16%in the fue gas-WAG fooding process.The calculation results of fue gas storage capacity showed that the injection gas storage capacity mainly consists of N_(2) and CO_(2),only N_(2) exists as free gas phase in cores,and other components of injection gas are dissolved in oil and water.Finally,injection strategies from three perspectives for fue gas storage,EOR,and combination of fue gas storage and EOR were proposed,respectively.
基金National Natural Science Foundation of China,Grant/Award Numbers:21871065,22071038Heilongjiang Touyan Team,Grant/Award Number:HITTY‐20190033Interdisciplinary Research Foundation of HIT,Grant/Award Number:IR2021205。
文摘Herein,we report bifunctional molybdenum-doped nickel sulfide on nickel foam(Mo-NiS_(x)/NF)for magnetic field-enhanced overall water splitting under alkaline conditions.Proper doping of Mo can lead to optimization of the electronic structure of NiS_(x),which accelerates the dissociation of H2O and the adsorption of OH−in the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)processes,respectively.In addition,the magnetically active Mo-NiS_(x)/NF can further enhance the HER and OER activity under an applied magnetic field due to the magnetoresistance effect and the ferromagnetic(FM)exchange-field penetration effect.As a result,Mo-NiS_(x)/NF requires low overpotentials of 307 mV at 50mA cm^(−2)(for OER)and 136 mV at 10mA cm^(−2)(for HER)under a magnetic field of 10000 G.Furthermore,the electrolytic cell constructed by the bifunctional Mo-NiS_(x)/NFs as both the cathode and the anode shows a low cell voltage of 1.594 V at 10 mA cm^(−2)with optimal stability over 60 h under the magnetic field.Simultaneous enhancement of the HER and OER processes by an external magnetic field through rational design of electrocatalysts might be promising for overall water splitting applications.
基金supported by the grants from Natural Science Foundation of China(Project No.61375045)the joint astronomic fund of the national natural science foundation of China and Chinese Academic Sinica(Project No.U1531242)Beijing Natural Science Foundation(4142030)
文摘In the past two decades, software aging has been studied by both academic and industry communities. Many scholars focused on analytical methods or time series to model software aging process. While machine learning has been shown as a very promising technique in application to forecast software state: normal or aging. In this paper, we proposed a method which can give practice guide to forecast software aging using machine learning algorithm. Firstly, we collected data from a running commercial web server and preprocessed these data. Secondly, feature selection algorithm was applied to find a subset of model parameters set. Thirdly, time series model was used to predict values of selected parameters in advance. Fourthly, some machine learning algorithms were used to model software aging process and to predict software aging. Fifthly, we used sensitivity analysis to analyze how heavily outcomes changed following input variables change. In the last, we applied our method to an IIS web server. Through analysis of the experiment results, we find that our proposed method can predict software aging in the early stage of system development life cycle.
基金the Presidential Incentive Awards(No.1103 and No.1105)MCCB summer research award in the University of North Georgia.
文摘The study of vehicular networks has attracted considerable interest in academia and the industry.In the broad area,connected vehicles and autonomous driving are technologies based on wireless data communication between vehicles or between vehicles and infrastructures.A Vehicle-to-Infrastructure(V2I)system consists of communications and computing over vehicles and related infrastructures.In such a system,wireless sensors are installed in some selected points along roads or driving areas.In autonomous driving,it is crucial for a vehicle to figure out the ideal routes by the communications between its equipped sensors and infrastructures then the vehicle is automatically moving along the routes.In this paper,we propose a Bezier curve based recursive algorithm,which effectively creates routes for vehicles through the communication between the On-Board Unit(OBU)and the Road-Side Units(RSUs).In addition,this approach generates a very low overhead.We conduct simulations to test the proposed algorithm in various situations.The experiment results demonstrate that our algorithm creates almost ideal routes.
基金Supported by the National Natural Science Foundation of China.
文摘An automated spectral classification technique for large sky surveys is proposed. We firstly perform spectral line matching to determine redshift candidates for an observed spectrum, and then estimate the spectral class by measuring the similarity between the observed spectrum and the shifted templates for each redshift candidate. As a byproduct of this approach, the spectral redshift can also be obtained with high accuracy. Compared with some approaches based on computerized learning methods in the literature, the proposed approach needs no training, which is time-consuming and sensitive to selection of the training set. Both simulated data and observed spectra are used to test the approach; the results show that the proposed method is efficient, and it can achieve a correct classification rate as high as 92.9%, 97.9% and 98.8% for stars, galaxies and quasars, respectively.
基金supported by the National Science Foundation of China under Grant No. 61402474by the Excellent Young Scholar Research Fund of Beijing Institute of Technology
文摘Internet of Vehicles(henceforth called IoV) is a public network system and high-value target for intrusions that may cause efficiency issues, privacy leakages or even physical damage. Conventional intrusion detection methods are normally designed for the Internet infrastructures which cannot directly apply in the context of IoV. This work proposes an FPGA based intrusion detection method that can not only achieve real-time scanning performance but also be applied in vehicular environment. We evaluate our scheme on a Xilinx FPGA based platform. Experiments show that the proposed system can achieve a throughput of more than 39 Gbps on existing FPGA platform which is about 15% higher than state-of-the-art techniques,and the total power consumption for the prototype is about 7.5 w. Moreover, the processing latency of the prototype is about 4 us and is about one sixtieth part of the popular software IDS systems.
基金Science and Technology Program of Huzhou City,No.2023GYB32.
文摘BACKGROUND Tardive dyskinesia(TD)is a serious and disabling movement disorder;it impairs social function and quality of life and increases the mortality rate.TD is usually induced by the use of antipsychotic drugs;however,the underlying mechanism remains unclear.Pharmacotherapy of TD includes cholinergic drugs,benzodiazepines,ginkgo biloba extract(GBE),antioxidants,amantadine,propanolol,botulinum toxin,valbenazine,and deutetrabenazine,whereas the non-pharmacotherapy approach includes modified electroconvulsive therapy(MECT)and deep brain stimulation.We successfully treated a chronic schizophrenia patient with comorbid long-term severe TD using deutetrabenazine,clozapine,and MECT.CASE SUMMARY A 69-year-old woman who was diagnosed as having schizophrenia 16 years ago developed severe TD after 6-mo prescription of risperidone oral solution.Her TD symptoms did not resolve despite various treatments,such as GBE,vitamin E,trihexyphenidyl,promethazine,benzodiazepines,and switching to quetiapine and olanzapine.After admission,she was given deutetrabenazine 6 mg bid.Her buccal tremor was slightly resolved 3 d later;however,her tongue remained protruded and could not be retracted.Quetiapine was switched to clozapine on day 4,and the buccal tremor remarkably resolved,and the tongue could be retracted into the mouth from day 6 onward.After three sessions of MECT,the buccal tremor resolved further.Since then,she has been able to take a semifluid diet,and her quality of life improved remarkably during 6 mo of follow-up.CONCLUSION TD is a serious condition which could be caused by antipsychotic medications;however,the best strategy against TD is prevention and monitoring during using antipsychotics.For patients with TD caused by antipsychotic medication use,multiple measures should be considered like switching to clozapine,adjunction with deutetrabenazine,or even MECT.
基金supported by the National Key Research and Development Program of China(2022YFB3204700)the National Natural Science Foundation of China(52122513)+2 种基金the Natural Science Foundation of Heilongjiang Province(YQ2021E022)the Natural Science Foundation of Chongqing(2023NSCQ-MSX2286)the Fundamental Research Funds for the Central Universities(HIT.BRET.2021010)。
文摘Single atom catalysts(SACs)have garnered significant attention in the field of catalysis over the past decade due to their exceptional atom utilization efficiency and distinct physical and chemical properties.For the semiconductor-based electrical gas sensor,the core is the catalysis process of target gas molecules on the sensitive materials.In this context,the SACs offer great potential for highly sensitive and selective gas sensing,however,only some of the bubbles come to the surface.To facilitate practical applications,we present a comprehensive review of the preparation strategies for SACs,with a focus on overcoming the challenges of aggregation and low loading.Extensive research efforts have been devoted to investigating the gas sensing mechanism,exploring sensitive materials,optimizing device structures,and refining signal post-processing techniques.Finally,the challenges and future perspectives on the SACs based gas sensing are presented.
