Due to the low content of alloying elements and the lack of effective nucleation sites,the fusion zone(FZ)of tungsten inert gas(TIG)welded AZ31 alloy typically exhibits undesirable coarse columnar grains,which can res...Due to the low content of alloying elements and the lack of effective nucleation sites,the fusion zone(FZ)of tungsten inert gas(TIG)welded AZ31 alloy typically exhibits undesirable coarse columnar grains,which can result in solidification defects and reduced mechanical properties.In this work,a novel welding wire containing MgO particles has been developed to promote columnar-to-equiaxed transition(CET)in the FZ of TIG-welded AZ31 alloy.The results show the achievement of a fully equiaxed grain structure in the FZ,with a significant 71.9%reduction in grain size to 41 μm from the original coarse columnar dendrites.Furthermore,the combination of using MgO-containing welding wire and pulse current can further refine the grain size to 25.6 μm.Microstructural analyses reveal the homogeneous distribution of MgO particles in the FZ.The application of pulse current results in an increase in the number density of MgO(1-2 μm)from 5.16 × 10^(4) m^(-3) to 6.18 × 10^(4) m^(-3).The good crystallographic matching relationship between MgO and α-Mg matrix,characterized by the orientation relationship of[11(2)0]α-Mg//[0(1)1]MgO and(0002)_(α-Mg)//(111)_(MgO),indicates that the MgO particles can act as effective nucleation sites for α-Mg to reduce nucleation undercooling.According to the Hunt criteria,the critical temperature gradient for CET is greatly enhanced due to the significantly increased number density of MgO nucleation sites.In addition,the correlation with the thermal simulation results reveals a transition in the solidification conditions within the welding pool from the columnar grain zone to the equiaxed grain zone in the CET map,leading to the realization of CET.The exceptional grain refinement has contributed to a simultaneous improvement in the strength and plasticity of welded joints.This study presents a novel strategy for controlling equiaxed microstructure and optimizing mechanical properties in fusion welding or wire and arc additive manufacturing of Mg alloy components.展开更多
Large solidification ranges and coarse columnar grains in the additively manufacturing of Al-Mg-Si alloys are normally involved in hot cracks during solidification.In this work,we develop novel crack-free Al-Mg_(2) Si...Large solidification ranges and coarse columnar grains in the additively manufacturing of Al-Mg-Si alloys are normally involved in hot cracks during solidification.In this work,we develop novel crack-free Al-Mg_(2) Si alloys fabricated by laser powder-bed fusion(L-PBF).The results indicate that the eutectic Mg_(2) Si phase possesses a strong ability to reduce crack susceptibility.It can enhance the grain growth restriction factor in the initial stage of solidification and promote eutectic filling in the terminal stage of solidifica-tion.The crack-free L-PBFed Al-x Mg_(2) Si alloys(x=6 wt.%,9 wt.%,and 12 wt.%)exhibit the combination of low crack susceptibility index(CSI),superior ability for liquid filling,and grain refinement.Particularly,the L-PBFed Al-9Mg_(2) Si alloy shows improved mechanical properties(e.g.yield strength of 397 MPa and elongation of 7.3%).However,the cracks are more likely to occur in the region near the columnar grain boundaries of the L-PBFed Al-3Mg_(2) Si alloy with a large solidification range and low eutectic content for liquid filling.Correspondingly,the L-PBFed Al-3Mg_(2) Si alloy shows poor bearing capacity of mechanical properties.The precise tuning of Mg_(2) Si eutectic content can offer an innovative strategy for eliminating cracks in additively manufactured Al-Mg-Si alloy.展开更多
AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge st...AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge straight tips with yellow and orange sleeves,respectively,were covered by a test chamber combined with a pressure sensor for measuring ACP.This was measured for 20s from 10s after starting aspiration in the linear mode using vacuum levels of 200 and 150 mm Hg with a 20-gauge tip,and 300 and 250 mm Hg with a 21-gauge tip.Using a porcine eye,a pressure sensor fixed with a 0.9 mm corneal incision measured ACP.For the posterior capsule contact assay,porcine eyes were treated as described above,and the ultrasonic needle tip was held at the height of the iris and aspirated for 30s in linear mode at a vacuum of 200 and 150 mm Hg for the 20-gauge tip,and 300 and 250 mm Hg for the 21-gauge tip.The bottle height at which the posterior capsule accidentally contacted the ultrasonic tip was recorded,and the estimated ACP was calculated.RESULTS:The internal pressure of the new tube chamber system and ACP from the porcine eye closely matched proportional changes at vacuum levels of 200 and 150 mm Hg with 20-gauge tips.Similarly,proportional changes at vacuum levels of 300 and 250 mm Hg with the 21-gauge tip were nearly equal.The bottle height at which the posterior capsule contacted with the tip and estimated ACP were 57.5±12.6 cm(20.2±7.9 mm Hg)at 200 mm Hg with a 20-gauge tip,35.0±10.0 cm(16.6±6.3 mm Hg)at 150 mm Hg with a 20-gauge tip,47.5±12.6 cm(18.7±8.7 mm Hg)at 300 mm Hg with a 21-gauge tip,and 32.5±5.0 cm(15.7±3.5 mm Hg)at 250 mm Hg with a 21-gauge tip.CONCLUSION:A comprehensive understanding of this chamber system’s characteristics and usage can resolve anterior chamber instability caused by changing preoperative settings on the phaco machine.展开更多
The article presents the results of in-kind measurements and numerical modeling of the formation of water characteristics in the Kama River,which is used for technical water supply in the production of potash fertiliz...The article presents the results of in-kind measurements and numerical modeling of the formation of water characteristics in the Kama River,which is used for technical water supply in the production of potash fertilizers.In the warm season,risks arise that threaten the sustainability of the water supply.It was found that in the summer,when the studied section of the Kama River is backed up by the KamaHydroelectric Power Station,there is a significant decrease in flow rates,which leads to vertical stratification of water properties.This,in turn,significantly limits the possibilities of using water fromthe bottom zone.Under conditions of significant water discharge from the reservoir,this section has river conditions with significantly higher flow rates.Under such conditions,intense vertical mixing of water masses occurs,which improves the consumer properties of water necessary for sustainable water supply.The results of numerical modeling carried out within the framework of the three-dimensional approach confirmed this conclusion.It is shown that with an increase in the flow rate in the channel near thewater intake,the concentration of salts decreases,which is an important factor in ensuring high-quality water supply.展开更多
Thework presents the electronic structure computations and optical spectroscopy studies of half-Heusler ScNiBi and YNiBi compounds.Our first-principles computations of the electronic structures were based on density f...Thework presents the electronic structure computations and optical spectroscopy studies of half-Heusler ScNiBi and YNiBi compounds.Our first-principles computations of the electronic structures were based on density functional theory accounting for spin-orbit coupling.These compounds are computed to be semiconductors.The calculated gap values make ScNiBi and YNiBi valid for thermoelectric and optoelectronic applications and as selective filters.In ScNiBi and YNiBi,an intense peak at the energy of−2 eV is composed of theNi 3d states in the conduction band,and the valence band mostly contains these states with some contributions from the Bi 6p and Sc 3d or Y 4d electronic states.These states participate in the formation of the indirect gap of 0.16 eV(ScNiBi)and 0.18 eV(YNiBi).Within the spectral ellipsometry technique in the interval 0.22–15μm of wavelength,the optical functions of materials are studied,and their dispersion features are revealed.A good matching of the experimental and modeled optical conductivity spectra allowed us to analyze orbital contributions.The abnormally low optical absorption observed in the low-energy region of the spectrum is referred to as the results of band calculations indicating a small density of electronic states near the Fermi energy of these complex materials.展开更多
Formalizing complex processes and phenomena of a real-world problem may require a large number of variables and constraints,resulting in what is termed a large-scale optimization problem.Nowadays,such large-scale opti...Formalizing complex processes and phenomena of a real-world problem may require a large number of variables and constraints,resulting in what is termed a large-scale optimization problem.Nowadays,such large-scale optimization problems are solved using computing machines,leading to an enormous computational time being required,which may delay deriving timely solutions.Decomposition methods,which partition a large-scale optimization problem into lower-dimensional subproblems,represent a key approach to addressing time-efficiency issues.There has been significant progress in both applied mathematics and emerging artificial intelligence approaches on this front.This work aims at providing an overview of the decomposition methods from both the mathematics and computer science points of view.We also remark on the state-of-the-art developments and recent applications of the decomposition methods,and discuss the future research and development perspectives.展开更多
In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utili...In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utilized to regulate signal communication between sensors and filters. Here, the randomly varying channel parameters are represented by a set of stochastic variables whose occurring probabilities are permitted to exhibit bounded uncertainty. Employing the spherical-radial cubature principle, a local filter under AaF relays is initially constructed. This construction ensures and minimizes an upper bound of the filtering error covariance by designing an appropriate filter gain. Subsequently, the local filters are fused through the application of the covariance intersection fusion rule. Furthermore, the uniform boundedness of the filtering error covariance's upper bound is investigated through establishing certain sufficient conditions. The effectiveness of the proposed CKFF scheme is ultimately validated via a simulation experiment concentrating on a three-phase induction machine.展开更多
The simultaneously transmitting and reflecting reconfigurable intelligent surface(STAR-RIS)is regarded as a promising paradigm for enhancing the connectivity and reliability of non-orthogonal multiple access(NOMA)netw...The simultaneously transmitting and reflecting reconfigurable intelligent surface(STAR-RIS)is regarded as a promising paradigm for enhancing the connectivity and reliability of non-orthogonal multiple access(NOMA)networks.However,the transmission of STAR-RIS enhanced NOMA networks performance is severely limited due to the inter-user interference(IUI)on multi-user detections.To mitigate this drawback,we propose a generalized quadrature spatial modulation(GQSM)aided STAR-RIS in conjunction with the NOMA scheme,termed STARRIS-NOMA-GQSM,to improve the performance of the corresponding NGMA network.By STAR-RISNOMA-GQSM,the information bits for all users in transmission and reflection zones are transmitted via orthogonal signal domains to eliminate the IUI so as to greatly improve the system performance.The lowcomplexity detection and upper-bounded bit error rate(BER)of STAR-RIS-NOMA-GQSM are both studied to evaluate its feasibility and performance.Moreover,by further utilizing index modulation(IM),we propose an enhanced STAR-RIS-NOMA-GQSM scheme,termed E-STAR-RIS-NOMA-GQSM,to enhance the transmission rate by dynamically adjusting reflection patterns in both transmission and reflection zones.Simulation results show that the proposed original and enhanced scheme significantly outperform the conventional STAR-RIS-NOMA and also confirm the precision of the theoretical analysis of the upper-bounded BER.展开更多
For the efficient electrolytic extraction of Er from spent nuclear fuel,a series of electrochemical methods was used to research the electrochemical behavior of Er(Ⅲ)in the LiCl—KCl system on inert(Mo)electrode and ...For the efficient electrolytic extraction of Er from spent nuclear fuel,a series of electrochemical methods was used to research the electrochemical behavior of Er(Ⅲ)in the LiCl—KCl system on inert(Mo)electrode and on reactive(Ni)electrodes.On the inert Mo electrode,the reduction of Er(Ⅲ)to Er(0)is a onestep with three-electron and quasi-reversible reaction process.Meanwhile,the apparent generation Gibbs free energy and activity coefficients of Er(Ⅲ)on the inert electrode were determined.Thereafter,the electrochemical reduction of Er(Ⅲ)on the Ni electrode was emphatically investigated.Er(Ⅲ)is reduced at a corrected potential owing to the formation of Ni-Er alloys.In addition,thermodynamic parameters such as partial excess Gibbs free energy change of Er in Ni,activity and apparent generation Gibbs free energy of the Ni-Er alloys were determined by the electromotive force method.Finally,different Ni-Er alloys were produced using potentiostatic electrolysis on the Ni cathode by controlling different potentials,Moreover,electrolytic extraction was carried out on the Ni cathode at the potential of-2.0 V,and the separation efficiency of Er reaches 99.72%,which proves the practicability of separating Er from LiCl-KCl eutectic on the reactive Ni cathode.展开更多
One of the most important of these emissions is fine particulate matter,which is a harmful emission of diesel engines,leading to the imposition of strict regulations.Biodiesel,with its high oxygen content,is an effect...One of the most important of these emissions is fine particulate matter,which is a harmful emission of diesel engines,leading to the imposition of strict regulations.Biodiesel,with its high oxygen content,is an effective alternative to significantly reduce these emissions.In this study,rapeseed methyl ester(RME)was used as a diesel engine fuel and the emitted particulate matter was comparedwith ultra-lowsulfur diesel(ULSD).Inmost experimental studies,the emission of soot wasmeasured.In this work,the effects of injection timing,injection pressure(IP),and engine load on fine particulate matter in both nucleation and accumulation modes were studied.The results show that IP increases the number of particles in the accumulation mode while the number of particles in the crystallization mode is higher for rapeseed methyl ester(RME)than for ultra-low sulfur diesel(ULSD).Conversely,the formation rates of particles in the accumulationmode are higher for ULSD.Cumulative concentration numbers(CCN)are generally higher for RME in crystallization mode but higher for ULSD in accumulation mode.Increasing the IP reduces the CCN values.The particle size in crystallizationmode reaches a maximum of 22 nm at IPs of 800 and 1000 bar but decreases to 15 nm at 1200 bar.Most fine particles fall in the 5–100 nm diameter range.High engine loads reduce the particle size distribution in nucleationmode for both fuels,with a slight increase in particle size in nucleationmode.Thestudy concluded that the use of rapeseed methyl ester as an engine fuel benefits the environment and improves air quality due to the significant reduction in the size,number,and concentration of nano-soot particles and total particles emitted from the engine.展开更多
Introduction Gender and sex are related to important quality and safety issues in scientific,health,and clinical research.Sex refers to biological characteristics,while gender encompasses the sociocultural norms,ident...Introduction Gender and sex are related to important quality and safety issues in scientific,health,and clinical research.Sex refers to biological characteristics,while gender encompasses the sociocultural norms,identities,and relationships that shape communities and organizations,as well as influence actions,behaviors,contexts,and knowledge.Both gender and sex intersect with other social categories.In this context,in addition to sex or gender,the intersectionality refers to overlapping or interdependent systems of discrimination by more than one factor,such as age,disability,ethnicity,geographic location,socioeconomic status,and sexuality,among others.展开更多
Cyber-physical systems(CPSs)are regarded as the backbone of the fourth industrial revolution,in which communication,physical processes,and computer technology are integrated.In modern industrial systems,CPSs are widel...Cyber-physical systems(CPSs)are regarded as the backbone of the fourth industrial revolution,in which communication,physical processes,and computer technology are integrated.In modern industrial systems,CPSs are widely utilized across various domains,such as smart grids,smart healthcare systems,smart vehicles,and smart manufacturing,among others.Due to their unique spatial distribution,CPSs are highly vulnerable to cyber-attacks,which may result in severe performance degradation and even system instability.Consequently,the security concerns of CPSs have attracted significant attention in recent years.In this paper,a comprehensive survey on the security issues of CPSs under cyber-attacks is provided.Firstly,mathematical descriptions of various types of cyberattacks are introduced in detail.Secondly,two types of secure estimation and control processing schemes,including robust methods and active methods,are reviewed.Thirdly,research findings related to secure control and estimation problems for different types of CPSs are summarized.Finally,the survey is concluded by outlining the challenges and suggesting potential research directions for the future.展开更多
Microscopic dynamic failure behaviors of rocks are significant to rock engineering,which is still insufficiently understood.This study combines split Hopkinson pressure bar(SHPB)and micro-CT(computed tomography)to exp...Microscopic dynamic failure behaviors of rocks are significant to rock engineering,which is still insufficiently understood.This study combines split Hopkinson pressure bar(SHPB)and micro-CT(computed tomography)to explore the microscopic failure characteristics of sandstone under impact loading.SHPB is responsible for the dynamic test,and micro-CT is responsible for pre-and post-test inspections.The results show that the pores and defect influence the dynamic strength but do not alter the overall trend of increased strength with a higher impact level.The dynamical crack development is then analyzed.Three types of cracks(i.e.I-,Y-,and H-type)are identified to describe the crack development.When rock is simply fractured,only I-type crack exists due to tensile failure,and it grows irregularly.As the strain rate increases,I-type crack is transformed into Y-and H-type crack due to shear failure.Crack coalesces at that moment,and the complexity increases along the impact direction.The coalescence occurs preferentially in the area with more pores,and around a third of pores are involved,where the maximum contribution area is in the middle of sample.Microcracks are formed inside the rock blocks,and rock grains and fragments fill in the cracks.The dynamic crack development is accompanied by microcracks,while rock grains and fragments result from the development of these microcracks.In addition,the influence of a semi-penetrating defect perpendicular to the impact direction is investigated.The defect can impede stress transfer and concentrate energy consumption.The findings are expected to enhance understanding of rock dynamics and support rock engineering development.展开更多
In this paper, the attack detection problem is investigated for a class of closed-loop systems subjected to unknownbutbounded noises in the presence of stealthy attacks. The measurement outputs from the sensors are qu...In this paper, the attack detection problem is investigated for a class of closed-loop systems subjected to unknownbutbounded noises in the presence of stealthy attacks. The measurement outputs from the sensors are quantized before transmission.A specific type of perfect stealthy attack, which meets certain rather stringent conditions, is taken into account. Such attacks could be injected by adversaries into both the sensor-toestimator and controller-to-actuator channels, with the aim of disrupting the normal data flow. For the purpose of defending against these perfect stealthy attacks, a novel scheme based on watermarks is developed. This scheme includes the injection of watermarks(applied to data prior to quantization) and the recovery of data(implemented before the data reaches the estimator).The watermark-based scheme is designed to be both timevarying and hidden from adversaries through incorporating a time-varying and bounded watermark signal. Subsequently, a watermark-based attack detection strategy is proposed which thoroughly considers the characteristics of perfect stealthy attacks,thereby ensuring that an alarm is activated upon the occurrence of such attacks. An example is provided to demonstrate the efficacy of the proposed mechanism for detecting attacks.展开更多
Developing low-permeability Coalbed Methane(CBM)reservoirs can significantly benefit from a comprehensive understanding of hydraulic fracture nucleation and propagation mechanisms,particularly in anthracite CBM reserv...Developing low-permeability Coalbed Methane(CBM)reservoirs can significantly benefit from a comprehensive understanding of hydraulic fracture nucleation and propagation mechanisms,particularly in anthracite CBM reservoirs.This study employs true-triaxial hydraulic fracturing experiments to investigate these mechanisms,with variables including injection flow rate,horizontal stress difference(σH-σh),and bedding orientation.Additionally,we conduct corresponding numerical cases to validate the experimental conclusions.The research also considers re-fracturing instances.For the first time,we utilize a combination of Kaiser tests and the stress transfer function in ANSYS Workbench finite element analysis to accurately restore the confining pressure of the coal sample.The findings suggest that a high initial injection flow rate during hydraulic fracturing can promote fluid leakage and aid in maintaining substantial fracture pressure.Enhanced fracturing efficiency can be achieved through higher injection rates,and it can ensure optimal fracturing efficiency,minimizing roof and floor fracturing in coal reservoirs to prevent fracturing fluid leakage.The presence of a high horizontal stress difference facilitates hydraulic fracture propagation along the direction of the maximum horizontal compressive stress,requiring a greater hydraulic pressure to produce more fracture systems in coal reservoirs.Additionally,a minor deviation in the wellbore injection direction from the bedding orientation assists in creating a complex hydraulic fractured network,although this also requires higher hydraulic pressure to initiate new fractures.In the case of multiple hydraulic fracturing,the second initiation pressure tends to be significantly higher than the first,indicating that a sequential increase in hydraulic pressure aids the formation of additional fractures.Moreover,a simplified numerical simulation has been conducted to corroborate the experimental findings.These insights are crucial in optimizing hydraulic fracturing processes to enhance the permeability of anthracite CBM reservoirs.展开更多
基金supported by the National Natural Science Foundation of China(No.51871155).
文摘Due to the low content of alloying elements and the lack of effective nucleation sites,the fusion zone(FZ)of tungsten inert gas(TIG)welded AZ31 alloy typically exhibits undesirable coarse columnar grains,which can result in solidification defects and reduced mechanical properties.In this work,a novel welding wire containing MgO particles has been developed to promote columnar-to-equiaxed transition(CET)in the FZ of TIG-welded AZ31 alloy.The results show the achievement of a fully equiaxed grain structure in the FZ,with a significant 71.9%reduction in grain size to 41 μm from the original coarse columnar dendrites.Furthermore,the combination of using MgO-containing welding wire and pulse current can further refine the grain size to 25.6 μm.Microstructural analyses reveal the homogeneous distribution of MgO particles in the FZ.The application of pulse current results in an increase in the number density of MgO(1-2 μm)from 5.16 × 10^(4) m^(-3) to 6.18 × 10^(4) m^(-3).The good crystallographic matching relationship between MgO and α-Mg matrix,characterized by the orientation relationship of[11(2)0]α-Mg//[0(1)1]MgO and(0002)_(α-Mg)//(111)_(MgO),indicates that the MgO particles can act as effective nucleation sites for α-Mg to reduce nucleation undercooling.According to the Hunt criteria,the critical temperature gradient for CET is greatly enhanced due to the significantly increased number density of MgO nucleation sites.In addition,the correlation with the thermal simulation results reveals a transition in the solidification conditions within the welding pool from the columnar grain zone to the equiaxed grain zone in the CET map,leading to the realization of CET.The exceptional grain refinement has contributed to a simultaneous improvement in the strength and plasticity of welded joints.This study presents a novel strategy for controlling equiaxed microstructure and optimizing mechanical properties in fusion welding or wire and arc additive manufacturing of Mg alloy components.
基金financially supported by the National Natural Science Foundation of China(Grant No.52071343)the Leading Innovation and Entrepreneurship Team of Zhejiang Province-Automotive Light Alloy Innovation Team(No.2022R01018).
文摘Large solidification ranges and coarse columnar grains in the additively manufacturing of Al-Mg-Si alloys are normally involved in hot cracks during solidification.In this work,we develop novel crack-free Al-Mg_(2) Si alloys fabricated by laser powder-bed fusion(L-PBF).The results indicate that the eutectic Mg_(2) Si phase possesses a strong ability to reduce crack susceptibility.It can enhance the grain growth restriction factor in the initial stage of solidification and promote eutectic filling in the terminal stage of solidifica-tion.The crack-free L-PBFed Al-x Mg_(2) Si alloys(x=6 wt.%,9 wt.%,and 12 wt.%)exhibit the combination of low crack susceptibility index(CSI),superior ability for liquid filling,and grain refinement.Particularly,the L-PBFed Al-9Mg_(2) Si alloy shows improved mechanical properties(e.g.yield strength of 397 MPa and elongation of 7.3%).However,the cracks are more likely to occur in the region near the columnar grain boundaries of the L-PBFed Al-3Mg_(2) Si alloy with a large solidification range and low eutectic content for liquid filling.Correspondingly,the L-PBFed Al-3Mg_(2) Si alloy shows poor bearing capacity of mechanical properties.The precise tuning of Mg_(2) Si eutectic content can offer an innovative strategy for eliminating cracks in additively manufactured Al-Mg-Si alloy.
文摘AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge straight tips with yellow and orange sleeves,respectively,were covered by a test chamber combined with a pressure sensor for measuring ACP.This was measured for 20s from 10s after starting aspiration in the linear mode using vacuum levels of 200 and 150 mm Hg with a 20-gauge tip,and 300 and 250 mm Hg with a 21-gauge tip.Using a porcine eye,a pressure sensor fixed with a 0.9 mm corneal incision measured ACP.For the posterior capsule contact assay,porcine eyes were treated as described above,and the ultrasonic needle tip was held at the height of the iris and aspirated for 30s in linear mode at a vacuum of 200 and 150 mm Hg for the 20-gauge tip,and 300 and 250 mm Hg for the 21-gauge tip.The bottle height at which the posterior capsule accidentally contacted the ultrasonic tip was recorded,and the estimated ACP was calculated.RESULTS:The internal pressure of the new tube chamber system and ACP from the porcine eye closely matched proportional changes at vacuum levels of 200 and 150 mm Hg with 20-gauge tips.Similarly,proportional changes at vacuum levels of 300 and 250 mm Hg with the 21-gauge tip were nearly equal.The bottle height at which the posterior capsule contacted with the tip and estimated ACP were 57.5±12.6 cm(20.2±7.9 mm Hg)at 200 mm Hg with a 20-gauge tip,35.0±10.0 cm(16.6±6.3 mm Hg)at 150 mm Hg with a 20-gauge tip,47.5±12.6 cm(18.7±8.7 mm Hg)at 300 mm Hg with a 21-gauge tip,and 32.5±5.0 cm(15.7±3.5 mm Hg)at 250 mm Hg with a 21-gauge tip.CONCLUSION:A comprehensive understanding of this chamber system’s characteristics and usage can resolve anterior chamber instability caused by changing preoperative settings on the phaco machine.
基金the Government of the Perm Territory within the Framework of Scientific Project No.S-26/828the Ministry of Science and High Education of Russia(Theme No.121031700169-1).
文摘The article presents the results of in-kind measurements and numerical modeling of the formation of water characteristics in the Kama River,which is used for technical water supply in the production of potash fertilizers.In the warm season,risks arise that threaten the sustainability of the water supply.It was found that in the summer,when the studied section of the Kama River is backed up by the KamaHydroelectric Power Station,there is a significant decrease in flow rates,which leads to vertical stratification of water properties.This,in turn,significantly limits the possibilities of using water fromthe bottom zone.Under conditions of significant water discharge from the reservoir,this section has river conditions with significantly higher flow rates.Under such conditions,intense vertical mixing of water masses occurs,which improves the consumer properties of water necessary for sustainable water supply.The results of numerical modeling carried out within the framework of the three-dimensional approach confirmed this conclusion.It is shown that with an increase in the flow rate in the channel near thewater intake,the concentration of salts decreases,which is an important factor in ensuring high-quality water supply.
文摘Thework presents the electronic structure computations and optical spectroscopy studies of half-Heusler ScNiBi and YNiBi compounds.Our first-principles computations of the electronic structures were based on density functional theory accounting for spin-orbit coupling.These compounds are computed to be semiconductors.The calculated gap values make ScNiBi and YNiBi valid for thermoelectric and optoelectronic applications and as selective filters.In ScNiBi and YNiBi,an intense peak at the energy of−2 eV is composed of theNi 3d states in the conduction band,and the valence band mostly contains these states with some contributions from the Bi 6p and Sc 3d or Y 4d electronic states.These states participate in the formation of the indirect gap of 0.16 eV(ScNiBi)and 0.18 eV(YNiBi).Within the spectral ellipsometry technique in the interval 0.22–15μm of wavelength,the optical functions of materials are studied,and their dispersion features are revealed.A good matching of the experimental and modeled optical conductivity spectra allowed us to analyze orbital contributions.The abnormally low optical absorption observed in the low-energy region of the spectrum is referred to as the results of band calculations indicating a small density of electronic states near the Fermi energy of these complex materials.
基金The Australian Research Council(DP200101197,DP230101107).
文摘Formalizing complex processes and phenomena of a real-world problem may require a large number of variables and constraints,resulting in what is termed a large-scale optimization problem.Nowadays,such large-scale optimization problems are solved using computing machines,leading to an enormous computational time being required,which may delay deriving timely solutions.Decomposition methods,which partition a large-scale optimization problem into lower-dimensional subproblems,represent a key approach to addressing time-efficiency issues.There has been significant progress in both applied mathematics and emerging artificial intelligence approaches on this front.This work aims at providing an overview of the decomposition methods from both the mathematics and computer science points of view.We also remark on the state-of-the-art developments and recent applications of the decomposition methods,and discuss the future research and development perspectives.
基金supported in part by the National Natural Science Foundation of China(12171124,61933007)the Natural Science Foundation of Heilongjiang Province of China(ZD2022F003)+2 种基金the National High-End Foreign Experts Recruitment Plan of China(G2023012004L)the Royal Society of UKthe Alexander von Humboldt Foundation of Germany
文摘In this paper, the problem of cubature Kalman fusion filtering(CKFF) is addressed for multi-sensor systems under amplify-and-forward(AaF) relays. For the purpose of facilitating data transmission, AaF relays are utilized to regulate signal communication between sensors and filters. Here, the randomly varying channel parameters are represented by a set of stochastic variables whose occurring probabilities are permitted to exhibit bounded uncertainty. Employing the spherical-radial cubature principle, a local filter under AaF relays is initially constructed. This construction ensures and minimizes an upper bound of the filtering error covariance by designing an appropriate filter gain. Subsequently, the local filters are fused through the application of the covariance intersection fusion rule. Furthermore, the uniform boundedness of the filtering error covariance's upper bound is investigated through establishing certain sufficient conditions. The effectiveness of the proposed CKFF scheme is ultimately validated via a simulation experiment concentrating on a three-phase induction machine.
基金supported in part by Guangdong Basic and Applied Basic Research Foundation under Grants 2023A1515030118 and 2024A1515010012in part by the Guangzhou Science and Technology Project under Grant 2023A03J0110+3 种基金in part by Guangzhou Basic Research Program Municipal School(College)Joint Funding Project under Grant 2025A03J3119in part by National Natural Science Foundation of China under Grant 62173101in part by the Key Discipline Project of Guangzhou Education Bureau under Grant 202255467in part by the Key Laboratory of on-Chip Communication and Sensor Chip of Guangdong Higher Education Institutes under Grant 2023KSYS002。
文摘The simultaneously transmitting and reflecting reconfigurable intelligent surface(STAR-RIS)is regarded as a promising paradigm for enhancing the connectivity and reliability of non-orthogonal multiple access(NOMA)networks.However,the transmission of STAR-RIS enhanced NOMA networks performance is severely limited due to the inter-user interference(IUI)on multi-user detections.To mitigate this drawback,we propose a generalized quadrature spatial modulation(GQSM)aided STAR-RIS in conjunction with the NOMA scheme,termed STARRIS-NOMA-GQSM,to improve the performance of the corresponding NGMA network.By STAR-RISNOMA-GQSM,the information bits for all users in transmission and reflection zones are transmitted via orthogonal signal domains to eliminate the IUI so as to greatly improve the system performance.The lowcomplexity detection and upper-bounded bit error rate(BER)of STAR-RIS-NOMA-GQSM are both studied to evaluate its feasibility and performance.Moreover,by further utilizing index modulation(IM),we propose an enhanced STAR-RIS-NOMA-GQSM scheme,termed E-STAR-RIS-NOMA-GQSM,to enhance the transmission rate by dynamically adjusting reflection patterns in both transmission and reflection zones.Simulation results show that the proposed original and enhanced scheme significantly outperform the conventional STAR-RIS-NOMA and also confirm the precision of the theoretical analysis of the upper-bounded BER.
基金Project supported by Ph.D.Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities(3072023GIP1005)。
文摘For the efficient electrolytic extraction of Er from spent nuclear fuel,a series of electrochemical methods was used to research the electrochemical behavior of Er(Ⅲ)in the LiCl—KCl system on inert(Mo)electrode and on reactive(Ni)electrodes.On the inert Mo electrode,the reduction of Er(Ⅲ)to Er(0)is a onestep with three-electron and quasi-reversible reaction process.Meanwhile,the apparent generation Gibbs free energy and activity coefficients of Er(Ⅲ)on the inert electrode were determined.Thereafter,the electrochemical reduction of Er(Ⅲ)on the Ni electrode was emphatically investigated.Er(Ⅲ)is reduced at a corrected potential owing to the formation of Ni-Er alloys.In addition,thermodynamic parameters such as partial excess Gibbs free energy change of Er in Ni,activity and apparent generation Gibbs free energy of the Ni-Er alloys were determined by the electromotive force method.Finally,different Ni-Er alloys were produced using potentiostatic electrolysis on the Ni cathode by controlling different potentials,Moreover,electrolytic extraction was carried out on the Ni cathode at the potential of-2.0 V,and the separation efficiency of Er reaches 99.72%,which proves the practicability of separating Er from LiCl-KCl eutectic on the reactive Ni cathode.
文摘One of the most important of these emissions is fine particulate matter,which is a harmful emission of diesel engines,leading to the imposition of strict regulations.Biodiesel,with its high oxygen content,is an effective alternative to significantly reduce these emissions.In this study,rapeseed methyl ester(RME)was used as a diesel engine fuel and the emitted particulate matter was comparedwith ultra-lowsulfur diesel(ULSD).Inmost experimental studies,the emission of soot wasmeasured.In this work,the effects of injection timing,injection pressure(IP),and engine load on fine particulate matter in both nucleation and accumulation modes were studied.The results show that IP increases the number of particles in the accumulation mode while the number of particles in the crystallization mode is higher for rapeseed methyl ester(RME)than for ultra-low sulfur diesel(ULSD).Conversely,the formation rates of particles in the accumulationmode are higher for ULSD.Cumulative concentration numbers(CCN)are generally higher for RME in crystallization mode but higher for ULSD in accumulation mode.Increasing the IP reduces the CCN values.The particle size in crystallizationmode reaches a maximum of 22 nm at IPs of 800 and 1000 bar but decreases to 15 nm at 1200 bar.Most fine particles fall in the 5–100 nm diameter range.High engine loads reduce the particle size distribution in nucleationmode for both fuels,with a slight increase in particle size in nucleationmode.Thestudy concluded that the use of rapeseed methyl ester as an engine fuel benefits the environment and improves air quality due to the significant reduction in the size,number,and concentration of nano-soot particles and total particles emitted from the engine.
基金funded by the European Union's Horizon 2020 Research and Innovation Programme under grant No.896932(TTV guide TX project)and grant No.824087(EOSC-Life)。
文摘Introduction Gender and sex are related to important quality and safety issues in scientific,health,and clinical research.Sex refers to biological characteristics,while gender encompasses the sociocultural norms,identities,and relationships that shape communities and organizations,as well as influence actions,behaviors,contexts,and knowledge.Both gender and sex intersect with other social categories.In this context,in addition to sex or gender,the intersectionality refers to overlapping or interdependent systems of discrimination by more than one factor,such as age,disability,ethnicity,geographic location,socioeconomic status,and sexuality,among others.
文摘Cyber-physical systems(CPSs)are regarded as the backbone of the fourth industrial revolution,in which communication,physical processes,and computer technology are integrated.In modern industrial systems,CPSs are widely utilized across various domains,such as smart grids,smart healthcare systems,smart vehicles,and smart manufacturing,among others.Due to their unique spatial distribution,CPSs are highly vulnerable to cyber-attacks,which may result in severe performance degradation and even system instability.Consequently,the security concerns of CPSs have attracted significant attention in recent years.In this paper,a comprehensive survey on the security issues of CPSs under cyber-attacks is provided.Firstly,mathematical descriptions of various types of cyberattacks are introduced in detail.Secondly,two types of secure estimation and control processing schemes,including robust methods and active methods,are reviewed.Thirdly,research findings related to secure control and estimation problems for different types of CPSs are summarized.Finally,the survey is concluded by outlining the challenges and suggesting potential research directions for the future.
基金supported by Research Center for Industries of the Future(RCIF)Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province(No.ZJRMG-2022-03)+1 种基金Key Research and Development Program of Guangxi Province(No.Guike AB22080035)which are gratefully acknowledged.In addition,we are grateful for the valuable and constructive feedback provided by the anonymous reviewers,which has greatly improved this manuscript.
文摘Microscopic dynamic failure behaviors of rocks are significant to rock engineering,which is still insufficiently understood.This study combines split Hopkinson pressure bar(SHPB)and micro-CT(computed tomography)to explore the microscopic failure characteristics of sandstone under impact loading.SHPB is responsible for the dynamic test,and micro-CT is responsible for pre-and post-test inspections.The results show that the pores and defect influence the dynamic strength but do not alter the overall trend of increased strength with a higher impact level.The dynamical crack development is then analyzed.Three types of cracks(i.e.I-,Y-,and H-type)are identified to describe the crack development.When rock is simply fractured,only I-type crack exists due to tensile failure,and it grows irregularly.As the strain rate increases,I-type crack is transformed into Y-and H-type crack due to shear failure.Crack coalesces at that moment,and the complexity increases along the impact direction.The coalescence occurs preferentially in the area with more pores,and around a third of pores are involved,where the maximum contribution area is in the middle of sample.Microcracks are formed inside the rock blocks,and rock grains and fragments fill in the cracks.The dynamic crack development is accompanied by microcracks,while rock grains and fragments result from the development of these microcracks.In addition,the influence of a semi-penetrating defect perpendicular to the impact direction is investigated.The defect can impede stress transfer and concentrate energy consumption.The findings are expected to enhance understanding of rock dynamics and support rock engineering development.
基金supported in part by the National Natural Science Foundation of China(61933007,62273087,62273088,U21A2019)the Shanghai Pujiang Program of China(22PJ1400400)+2 种基金the Hainan Province Science and Technology Special Fund of China(ZDYF2022SHFZ105)the Royal Society of U.K.the Alexander von Humboldt Foundation of Germany
文摘In this paper, the attack detection problem is investigated for a class of closed-loop systems subjected to unknownbutbounded noises in the presence of stealthy attacks. The measurement outputs from the sensors are quantized before transmission.A specific type of perfect stealthy attack, which meets certain rather stringent conditions, is taken into account. Such attacks could be injected by adversaries into both the sensor-toestimator and controller-to-actuator channels, with the aim of disrupting the normal data flow. For the purpose of defending against these perfect stealthy attacks, a novel scheme based on watermarks is developed. This scheme includes the injection of watermarks(applied to data prior to quantization) and the recovery of data(implemented before the data reaches the estimator).The watermark-based scheme is designed to be both timevarying and hidden from adversaries through incorporating a time-varying and bounded watermark signal. Subsequently, a watermark-based attack detection strategy is proposed which thoroughly considers the characteristics of perfect stealthy attacks,thereby ensuring that an alarm is activated upon the occurrence of such attacks. An example is provided to demonstrate the efficacy of the proposed mechanism for detecting attacks.
基金funded by the National Natural Science Foundation of China(No.42202155)China Postdoctoral Science Foundation(No.2021MD703807)+7 种基金Heilongjiang Provincial Postdoctoral Science Foundation(No.LBH-Z20121)financial support from the China Scholarship Council(No.202008230018)the Research Fund Program of Hubei Key Laboratory of Resources and Eco-Environment Geology(No.HBREGKFJJ-202309)funding by the DGICYT Spanish Project(grant no.PID2020-118999GB-I00)funded by the MCIN/AEI/10.13039/501100011033funding by the Ramón y Cajal fellowship(grant no.RyC-2018-026335-I)funded by the MCIN/AEI/10.13039/50110001103the European Social Fund-Investing in Your Future.
文摘Developing low-permeability Coalbed Methane(CBM)reservoirs can significantly benefit from a comprehensive understanding of hydraulic fracture nucleation and propagation mechanisms,particularly in anthracite CBM reservoirs.This study employs true-triaxial hydraulic fracturing experiments to investigate these mechanisms,with variables including injection flow rate,horizontal stress difference(σH-σh),and bedding orientation.Additionally,we conduct corresponding numerical cases to validate the experimental conclusions.The research also considers re-fracturing instances.For the first time,we utilize a combination of Kaiser tests and the stress transfer function in ANSYS Workbench finite element analysis to accurately restore the confining pressure of the coal sample.The findings suggest that a high initial injection flow rate during hydraulic fracturing can promote fluid leakage and aid in maintaining substantial fracture pressure.Enhanced fracturing efficiency can be achieved through higher injection rates,and it can ensure optimal fracturing efficiency,minimizing roof and floor fracturing in coal reservoirs to prevent fracturing fluid leakage.The presence of a high horizontal stress difference facilitates hydraulic fracture propagation along the direction of the maximum horizontal compressive stress,requiring a greater hydraulic pressure to produce more fracture systems in coal reservoirs.Additionally,a minor deviation in the wellbore injection direction from the bedding orientation assists in creating a complex hydraulic fractured network,although this also requires higher hydraulic pressure to initiate new fractures.In the case of multiple hydraulic fracturing,the second initiation pressure tends to be significantly higher than the first,indicating that a sequential increase in hydraulic pressure aids the formation of additional fractures.Moreover,a simplified numerical simulation has been conducted to corroborate the experimental findings.These insights are crucial in optimizing hydraulic fracturing processes to enhance the permeability of anthracite CBM reservoirs.
