A discontinuous smoothed particle hydrodynamics(DSPH)method considering block contacts is originally developed to model the cracking,frictional slip and large deformation in rock masses,and is verified by theoretical,...A discontinuous smoothed particle hydrodynamics(DSPH)method considering block contacts is originally developed to model the cracking,frictional slip and large deformation in rock masses,and is verified by theoretical,numerical and/or experimental results.In the DSPH method,cracking is realized by breaking the virtual bonds via a pseudo-spring method based on Mohr–Coulomb failure criteria.The damaged particles are instantaneously replaced by discontinuous particles and the contact bond between the original and discontinuous particles is formed to simulate the frictional slip and separation/contraction between fracture surfaces based on the block contact algorithm.The motion of rock blocks and the contact force of discontinuous particles are determined following Newton's second law.The results indicate that the DSPH method precisely captures the cracking,contact formation and complete failure across six numerical benchmark tests.This single smoothed particle hydrodynamics(SPH)framework could significantly improve computational efficiency and is potentially applicable to broad multi-physical rock engineering problems of different scales.展开更多
Background:Continuous care for children with enterostomy and their families has been gaining popularity in China.Objective:To evaluate the feasibility of continuous care for children with enterostomy and their familie...Background:Continuous care for children with enterostomy and their families has been gaining popularity in China.Objective:To evaluate the feasibility of continuous care for children with enterostomy and their families in China.Methods:The PubMed,Web of Science,Embase,Cochrane Library,EBSCO,CNKI,CBM,VIP,and WanFang were searched for clinical trials until December 30,2025.Two reviewers independently searched articles,evaluated quality and extracted data.This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA).Results:33 studies involving 2774 participants were included.The meta-analysis showed that continuous care strategy can significantly reduce the incidence of complications in children with enterostomy(OR=0.20,95%CI=0.16-0.26,p<0.001,I2=0%),effectively improve the family caregiver ability for enterostomy(MD=-10.34,95%CI=-13.82 to-6.85,p<0.001,I2=99%),shorten the time for family members to replace stoma bags(MD=-13.57,95%CI=-19.66 to-7.49,p<0.001,I2=100%),and alleviate negative emotions such as anxiety(SMD=-1.80,95%CI=-2.36 to-1.23,p<0.001,I2=92%)and depression(SMD=-1.54,95%CI=-2.04 to-1.04,p<0.001,I2=89%)in the families of the affected children.Conclusions:Continuous care can reduce complications of enterostomy in children,improve the family caregiver ability for enterostomy and alleviate negative emotions of family members such as anxiety and depression.展开更多
We report an immobilized enzyme-catalyzed batch and continuous-flow synthesis of optically pure ethyl(R)-pantothenate((R)-PaOEt),the direct precursor of d-pantothenic acid.Firstly,a ketoreductase mutant designated as ...We report an immobilized enzyme-catalyzed batch and continuous-flow synthesis of optically pure ethyl(R)-pantothenate((R)-PaOEt),the direct precursor of d-pantothenic acid.Firstly,a ketoreductase mutant designated as M2,carrying two-point mutations of F97L and M242F relative to the wild-type SSCR,was constructed by site-directed mutagenesis,exhibited simultaneously improved activity toward ethyl 2′-ketopantothenate(K-PaOEt)and isopropanol,and could effectively catalyze the stereoselective reduction of K-PaOEt to(R)-PaOEt by using isopropanol as the sacrificial co-substrate to regenerate NADPH.After screening six commercially available carriers,an amino resin LXTE-700 was identified as the best solid support for the immobilization of M2 via the glutaraldehyde activation method.Upon optimization of the immobilization process and reaction conditions,the fabricated immobilized enzyme M2@amino resin demonstrated excellent recyclability and reusability,with the complete conversion of K-PaOEt to(R)-PaOEt being still realized after 12 cycles of reuse.Finally,M2@amino resin-catalyzed synthesis of(R)-PaOEt was successfully implemented in continuous-flow,accomplishing a 6.3 times higher space-time yield than that with the batch synthesis(529.2 versus 84 g L^(-1) d^(-1)).Our developed flow biocatalysis system also features an outstanding operational stability,as evidenced by the 100%conversion rate achieved after 15 consecutive days of operation.展开更多
The northern segment of the North-South Seismic Belt is characterized by intense crustal deformation,well-developed active tectonics,and frequent occurrences of strong earthquakes.Therefore,conducting a Probabilistic ...The northern segment of the North-South Seismic Belt is characterized by intense crustal deformation,well-developed active tectonics,and frequent occurrences of strong earthquakes.Therefore,conducting a Probabilistic Seismic Hazard Analysis(PSHA)for this region is of significant importance for supporting seismic fortification in major engineering projects and formulating disaster prevention and mitigation policies.In this study,a composite seismic source model was constructed by integrating data on historical earthquakes,active faults,and paleoseismicity.Furthermore,a logic tree framework was employed to quantify epistemic uncertainties,enabling a systematic seismic hazard assessment of the region.To more accurately characterize the spatial heterogeneity of seismic activity,improvements were made to both the Circular Spatial Smoothing Model(CSSM)with a fixed radius and the Adaptive Spatial Smoothing Model(ASSM),with full consideration given to the spatiotemporal completeness of historical earthquake magnitudes.Regarding the CSSM,for scenarios involving small sample sizes in earthquake catalogs,the cross-validation method proposed in this study demonstrated higher robustness than the maximum likelihood method in determining the optimal correlation distance.Performance evaluation results indicate that while both models effectively characterize seismic activity,the ASSM exhibits superior overall predictive performance compared to the CSSM,owing to its ability to adaptively adjust the smoothing radius according to seismic density.Significant discrepancies were observed in the Peak Ground Acceleration(PGA)results calculated with a 10%probability of exceedance in 50 years across different combinations of seismic source models.The single spatially smoothed point-source model yielded a maximum PGA of approximately 0.52 g,with high-value areas concentrated near historical epicenters,thereby significantly underestimating the hazard associated with major fault zones.When combined with the simple fault-source model,the maximum PGA increased to 0.8 g,with high-value zones exhibiting a zonal distribution along faults;however,the risk remained underestimated for faults with low slip rates that are nevertheless approaching their recurrence cycles.Following the introduction of the time-dependent characteristic fault-source model,local PGA values for faults in the middle-to-late stages of their recurrence cycles increased by a factor of 2 to 7 compared to the single model.These results demonstrate that the characteristic fault-source model reasonably delineates the time-dependence of large earthquake recurrence,thereby providing a more accurate assessment of imminent seismic risks.By comprehensively applying the improved spatially smoothed pointsource model,the simple fault-source model,and the characteristic fault-source model,the following faults within the region were identified as having high seismic hazard:the Huangxianggou,Zhangxian,and Tianshui segments of the Xiqinling northern edge fault;the Maqin-Maqu segment of the Dongkunlun fault;the Longriqu fault;the Maoergai fault;the Elashan fault;the Riyueshan fault;the eastern segment of the Lenglongling fault;the Maxianshan segment of the Maxianshan northern Margin fault;and the Maomaoshan-Jinqianghe segment of the Laohushan-Maomaoshan fault.As these faults are located within seismic gaps or are approaching the recurrence periods of large earthquakes,they should be prioritized for current and future seismic monitoring as well as disaster prevention and mitigation efforts.展开更多
A full-sectional microstructure characterization method was developed to investigate the formation of coarse slag rims during the continuous casting of hypo-peritectic steel.The cross-sectional microstructural analysi...A full-sectional microstructure characterization method was developed to investigate the formation of coarse slag rims during the continuous casting of hypo-peritectic steel.The cross-sectional microstructural analysis of typical slag rims for two highly crystalline powders revealed that their formation was primarily driven by the solidification of the liquid slag.Distinct differences were observed in the microstructures of slag rims from the two powders.Powder A(characterized by a higher breaking temperature and viscosity)displayed alternating lamellar microstructures of coarse and fine phases,with the coarse phases composed of akermanite-gehlenite transition phases.In contrast,powder B(with a lower breaking temperature and viscosity)predominantly comprised regular akermanite-gehlenite crystals interspersed with a certain amount of glassy phases.Numerical simulations of a three-phase fluid flow coupled with heat transfer indicate that slag rim formation correlates with mold oscillation.Solidification of the liquid slag at the slag rim front predominantly occurs during the negative stroke of the mold oscillation.The average heating rate during the ascending stage of the mold reaches approximately 100 K·s^(−1),whereas the average cooling rate during the descending stage attains 400 K·s^(−1).This temperature variation leads to the formation of lamellar microstructures,whereas the ascending stage promotes the formation of coarse structures and thicker slag rims.Based on the powder properties,two distinct formation pathways exist for highly crystalline mold powders.For the powders with a higher breaking temperature,higher viscosity,and narrower solidification range(powder A),coarse microstructures and thicker slag rims were preferentially formed.For powders with lower breaking temperature and viscosity and wider solidification ranges(powder B),the liquid slag resisted rapid solidification,and the extended mushy zone allowed the partial liquid slag to persist at the slag rim front,promoting the formation of a thin slag rim.This study enhances the understanding of slag rim formation in highly crystalline mold powders and provides critical insights into the control of longitudinal surface cracks in hypo-peritectic steel.展开更多
A concept of the independent-continuous topological variable is proposed to establish its corresponding smooth model of structural topological optimization. The method can overcome difficulties that are encountered in...A concept of the independent-continuous topological variable is proposed to establish its corresponding smooth model of structural topological optimization. The method can overcome difficulties that are encountered in conventional models and algorithms for the optimization of the structural topology. Its application to truss topological optimization with stress and displacement constraints is satisfactory, with convergence faster than that of sectional optimizations.展开更多
The contact stiffness of the joint surface directly affects the static and dynamic mechanical behavior,and accuracy of the machine tool.A new elastoplastic contact stiffness model is proposed by considering continuous...The contact stiffness of the joint surface directly affects the static and dynamic mechanical behavior,and accuracy of the machine tool.A new elastoplastic contact stiffness model is proposed by considering continuous and smooth contact characteristics and substrate deformation.First,the interpolation interval of cubic Hermite polynomials is improved to meet the continuous and smooth change of contact parameters during asperity deformation.Then,the micro-contact mechanism considering substrate deformation is explored by establishing an asperity-substrate system model.Furthermore,combined with statistical principles,a new contact stiffness model of the joint surface is established.Finally,the correctness of the built model is verified by comparing with experimental data and different contact models.The simulation results show that the model changes continuously and smoothly in the three deformation regions.The substrate deformation mainly affects the asperities in the elastic contact stage.The smoother is the surface,the more significant is the influence of substrate deformation.展开更多
To improve the smoothness of motion control in a quadruped robot, a continuous and smooth gait transition method based on central pattern generator （CPG） was presented to solve the unsmooth or failed problem which m...To improve the smoothness of motion control in a quadruped robot, a continuous and smooth gait transition method based on central pattern generator （CPG） was presented to solve the unsmooth or failed problem which may result in phase-locked or sharp point with direct replacement of the gait matrix. Through improving conventional weight matrix, a CPG network and a MATLAB/ Simulink model were constructed based on the Hopf oscillator for gait generation and transition in the quadruped robot. A co-simulation was performed using ADAMS/MATLAB for the gait transition between walk and trot to verify the correctness and effectiveness of the proposed CPG gait generation and transition algorithms. Related methods and conclusions can technically support the motion control technology of the quadruped robot.展开更多
Traditional packet switching networks have typically employed window-based congestion control schemes in order to regulate traffic flow. In ATM networks, the high speed of the communication links and the varied nature...Traditional packet switching networks have typically employed window-based congestion control schemes in order to regulate traffic flow. In ATM networks, the high speed of the communication links and the varied nature of the carried traffic make such schemes inappropriate. Therefore, simpler and more efficient schemes have to be proposed to improve the congestion control for ATM switching. This paper presents an exact performance analysis of ATM switching whose inputs consist of Continuous-Bit-Rate(CBR) and bursty traffic. The CBR traffic and bursty traffic are described by Bernoulli process and the Interrupted Bernoulli Process(IBP), respectively. Bursty traffic smoothing mechanism is analyzed. With the use of a recursive algorithm, the cell loss probability and the average delay for ATM switching of mixed CBR and bursty traffic are exactly calculated. Traffic smoothing could be implemented at a slower peak rate keeping the average rate constant or decreasing the average bursty length. Both numerical展开更多
With an inequality and some analysis techniques,iterative approximation of fixed points for uniformly continuous and strongly pseudocontractive mappings in smooth Banach spaces is studied,and the recent corresponding ...With an inequality and some analysis techniques,iterative approximation of fixed points for uniformly continuous and strongly pseudocontractive mappings in smooth Banach spaces is studied,and the recent corresponding results of Chidume are improved.展开更多
BACKGROUND Continuous glucose monitoring(CGM)metrics,such as time in range(TIR)and glycemic risk index(GRI),have been linked to various diabetes-related complications,including diabetic foot(DF).AIM To investigate the...BACKGROUND Continuous glucose monitoring(CGM)metrics,such as time in range(TIR)and glycemic risk index(GRI),have been linked to various diabetes-related complications,including diabetic foot(DF).AIM To investigate the association between CGM-derived indicators and the risk of DF in individuals with type 2 diabetes mellitus(T2DM).METHODS A total of 591 individuals with T2DM(297 with DF and 294 without DF)were enrolled.Relevant clinical data,complications,comorbidities,hematological parameters,and 72-hour CGM data were collected.Logistic regression analysis was employed to examine the relationship between these measurements and the risk of DF.RESULTS Individuals with DF exhibited higher mean blood glucose(MBG)levels and increased proportions of time above range(TAR),TAR level 1,and TAR level 2,but lower TIR(all P<0.001).Patients with DF had significantly lower rates of achieving target ranges for TIR,TAR,and TAR level 2 than those without DF(all P<0.05).Logistic regression analysis revealed that GRI,MBG,and TAR level 1 were positively associated with DF risk,while TIR was inversely correlated(all P<0.05).Achieving TIR and TAR was inversely correlated with white blood cell count and glycated hemoglobin A1c levels(P<0.05).Additionally,achieving TAR was influenced by fasting plasma glucose,body mass index,diabetes duration,and antidiabetic medication use.CONCLUSION CGM metrics,particularly TIR and GRI,are significantly associated with the risk of DF in T2DM,emphasizing the importance of improved glucose control.展开更多
Vein graft(VG)failure(VGF)is associated with VG intimal hyperplasia,which is characterized by abnormal accumulation of vascular smooth muscle cells(VSMCs).Most neointimal VSMCs are derived from pre-existing VSMCs via ...Vein graft(VG)failure(VGF)is associated with VG intimal hyperplasia,which is characterized by abnormal accumulation of vascular smooth muscle cells(VSMCs).Most neointimal VSMCs are derived from pre-existing VSMCs via a process of VSMC phenotypic transition,also known as dedifferentiation.There is increasing evidence to suggest that ginger or its bioactive ingredients may block VSMC dedifferentiation,exerting vasoprotective functions;however,the precise mechanisms have not been fully characterized.Therefore,we investigated the effect of ginger on VSMC phenotypic transition in VG remodeling after transplantation.Ginger significantly inhibited neointimal hyperplasia and promoted lumen(L)opening in a 3-month VG,which was primarily achieved by reducing ferroptotic stress.Ferroptotic stress is a pro-ferroptotic state.Contractile VSMCs did not die but instead gained a proliferative capacity and switched to the secretory type,forming neointima(NI)after vein transplantation.Ginger and its two main vasoprotective ingredients(6-gingerol and 6-shogaol)inhibit VSMC dedifferentiation by reducing ferroptotic stress.Network pharmacology analysis revealed that 6-gingerol inhibits ferroptotic stress by targeting P53,while 6-shogaol inhibits ferroptotic stress by targeting 5-lipoxygenase(Alox5),both promoting ferroptosis.Furthermore,both ingredients co-target peroxisome proliferator-activated receptor gamma(PPARγ),decreasing PPARγ-mediated nicotinamide adenine dinucleotide phosphate(NADPH)oxidase 1(Nox1)expression.Nox1 promotes intracellular reactive oxygen species(ROS)production and directly induces VSMC dedifferentiation.In addition,Nox1 is a ferroptosis-promoting gene that encourages ferroptotic stress production,indirectly leading to VSMC dedifferentiation.Ginger,a natural multi-targeted ferroptotic stress inhibitor,finely and effectively prevents VSMC phenotypic transition and protects against venous injury remodeling.展开更多
This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanis...This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanism is presented to structure the adaptive integral terminal sliding mode control(SMC)strategy.The control design consists of compensation control and nominal control,which improves the rapidity and accuracy of trajectory tracking.The smooth saturation model based on the error function is applied to approximate the voltage saturation phenomenon.Additionally,to deal with the adverse effects of various unknown disturbances,including model parameter uncertainties and unknown external load disturbances,an improved disturbance observer(DO)is proposed.This observer effectively suppresses the fluctuations caused by fixed gain during the starting period of the system.Finally,the experimental results under different conditions show that the proposed strategy has good tracking and disturbance suppression performances.展开更多
The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large de...The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large deformation during the LCR process and to minimize the thickness of the slab in bending segments,the maximum theoretical reduction amount and the corresponding reduction scheme for the LCR process must be determined.With SPA-H weathering steel as a specific research steel grade,the distributions of tem-perature and deformation fields of a slab with the LCR process were analyzed using a three-dimensional thermal-mechanical finite ele-ment model.High-temperature tensile tests were designed to determine the critical strain of corner crack propagation and intermediate crack initiation with various strain rates and temperatures,and a prediction model of the critical strain for two typical cracks,combining the effects of strain rate and temperature,was proposed by incorporating the Zener-Hollomon parameter.The crack risks with different LCR schemes were calculated using the crack risk prediction model,and the maximum theoretical reduction amount for the SPA-H slab with a transverse section of 145 mm×1600 mm was 41.8 mm,with corresponding reduction amounts for Segment 0 to Segment 4 of 15.8,7.3,6.5,6.4,and 5.8 mm,respectively.展开更多
During extensive gully land consolidation projects on China's Loess Plateau,many loess-bedrock fill slopes were formed,which frequently experience shallow landslides induced by rainfall.However,studies on loess-be...During extensive gully land consolidation projects on China's Loess Plateau,many loess-bedrock fill slopes were formed,which frequently experience shallow landslides induced by rainfall.However,studies on loess-bedrock slope failure triggered by continuous heavy rainfall are limited,and the role of the soilerock interface between the original bedrock slope and fill slope in the hydrological and failure process of the slope remains unclear.In this study,we conducted a continuous rainfall model test on a loess-bedrock fill slope.During the test,the responses of volume water content,pore pressure,micro deformation,and movement of the infiltration front were observed.The hydrological process and failure mechanism were then analysed.The findings suggest that the soilerock interface is a predominant infiltration surface within the slope.Rainfall infiltration rates at the interface reach 1.24-2.80 times those of the fill slope,with peak interfacial pore water pressure exceeding that of the loess fill.Furthermore,the infiltration front moves rapidly along the interface toward the bottom of the slope,reducing interfacial cohesion between bedrock and loess.The slope failure modes are summarised into three phases:local failure→flow slide and crack penetration→multistage block retrogressive slides.The cracks generated at the slope surface serve as key determinants of the geometry and scale of shallow landslides.Therefore,we recommend targeted engineering interventions to mitigate the instability and erosion of loessebedrock fill slopes.展开更多
Based on thermodynamic calculations and continuous rheological extrusion(CRE)technology,Al-Ti-V-B master alloys were designed and prepared.The morphology and the distribution of the refined phases in the master alloys...Based on thermodynamic calculations and continuous rheological extrusion(CRE)technology,Al-Ti-V-B master alloys were designed and prepared.The morphology and the distribution of the refined phases in the master alloys were analyzed by XRD,SEM,and TEM.The effects of master alloy addition and holding time on the microstructure and mechanical properties of A356 alloy were investigated.Under the optimum refiner addition of 0.3wt.%and the holding time of 20 min,the average grain size of the refined A356 alloy is 151.8±9.11μm,89.62%lower than that of original A356 alloy.The tensile strength and elongation of as-cast A356refined alloy are 196.11 MPa and 5.75%,respectively.After T6 treatment,the tensile strength and elongation of A356 refined alloy are 290.1 MPa and 3.09%,respectively.The fracture morphology is characterized by a predominance of along-crystal fracture with a small amount of through-crystal fracture,attributed to the refined grains.Finer grains promote crack path deflection and localized plastic deformation,enhancing energy dissipation and reducing the tendency for brittle fracture.This study provides a novel approach to improving the mechanical properties of A356 alloy through grain refinement using CRE Al-Ti-V-B master alloy.展开更多
Ensuring the consistent mechanical performance of three-dimensional(3D)-printed continuous fiber-reinforced composites is a significant challenge in additive manufacturing.The current reliance on manual monitoring exa...Ensuring the consistent mechanical performance of three-dimensional(3D)-printed continuous fiber-reinforced composites is a significant challenge in additive manufacturing.The current reliance on manual monitoring exacerbates this challenge by rendering the process vulnerable to environmental changes and unexpected factors,resulting in defects and inconsistent product quality,particularly in unmanned long-term operations or printing in extreme environments.To address these issues,we developed a process monitoring and closed-loop feedback control strategy for the 3D printing process.Real-time printing image data were captured and analyzed using a well-trained neural network model,and a real-time control module-enabled closed-loop feedback control of the flow rate was developed.The neural network model,which was based on image processing and artificial intelligence,enabled the recognition of flow rate values with an accuracy of 94.70%.The experimental results showed significant improvements in both the surface performance and mechanical properties of printed composites,with three to six times improvement in tensile strength and elastic modulus,demonstrating the effectiveness of the strategy.This study provides a generalized process monitoring and feedback control method for the 3D printing of continuous fiber-reinforced composites,and offers a potential solution for remote online monitoring and closed-loop adjustment in unmanned or extreme space environments.展开更多
We study the Cauchy problem of the Kolmogorov-Fokker-Planck equations and show that the solution enjoys an analytic smoothing effect with L?initial datum for positive time.
基金financial support from the National Key Research and Development Program of China(Grant No.2019YFC1509702)the Fundamental Research Funds for the Central Universities in Chinathe National Natural Science Foundation of China(Grant No.42377162).
文摘A discontinuous smoothed particle hydrodynamics(DSPH)method considering block contacts is originally developed to model the cracking,frictional slip and large deformation in rock masses,and is verified by theoretical,numerical and/or experimental results.In the DSPH method,cracking is realized by breaking the virtual bonds via a pseudo-spring method based on Mohr–Coulomb failure criteria.The damaged particles are instantaneously replaced by discontinuous particles and the contact bond between the original and discontinuous particles is formed to simulate the frictional slip and separation/contraction between fracture surfaces based on the block contact algorithm.The motion of rock blocks and the contact force of discontinuous particles are determined following Newton's second law.The results indicate that the DSPH method precisely captures the cracking,contact formation and complete failure across six numerical benchmark tests.This single smoothed particle hydrodynamics(SPH)framework could significantly improve computational efficiency and is potentially applicable to broad multi-physical rock engineering problems of different scales.
文摘Background:Continuous care for children with enterostomy and their families has been gaining popularity in China.Objective:To evaluate the feasibility of continuous care for children with enterostomy and their families in China.Methods:The PubMed,Web of Science,Embase,Cochrane Library,EBSCO,CNKI,CBM,VIP,and WanFang were searched for clinical trials until December 30,2025.Two reviewers independently searched articles,evaluated quality and extracted data.This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA).Results:33 studies involving 2774 participants were included.The meta-analysis showed that continuous care strategy can significantly reduce the incidence of complications in children with enterostomy(OR=0.20,95%CI=0.16-0.26,p<0.001,I2=0%),effectively improve the family caregiver ability for enterostomy(MD=-10.34,95%CI=-13.82 to-6.85,p<0.001,I2=99%),shorten the time for family members to replace stoma bags(MD=-13.57,95%CI=-19.66 to-7.49,p<0.001,I2=100%),and alleviate negative emotions such as anxiety(SMD=-1.80,95%CI=-2.36 to-1.23,p<0.001,I2=92%)and depression(SMD=-1.54,95%CI=-2.04 to-1.04,p<0.001,I2=89%)in the families of the affected children.Conclusions:Continuous care can reduce complications of enterostomy in children,improve the family caregiver ability for enterostomy and alleviate negative emotions of family members such as anxiety and depression.
基金the Science and Technology R&D Major Project of Jiangxi Province(No.20244AFI92001)the National Natural Science Foundation of China(Nos.22071033 and 21801047)for the financial supports.
文摘We report an immobilized enzyme-catalyzed batch and continuous-flow synthesis of optically pure ethyl(R)-pantothenate((R)-PaOEt),the direct precursor of d-pantothenic acid.Firstly,a ketoreductase mutant designated as M2,carrying two-point mutations of F97L and M242F relative to the wild-type SSCR,was constructed by site-directed mutagenesis,exhibited simultaneously improved activity toward ethyl 2′-ketopantothenate(K-PaOEt)and isopropanol,and could effectively catalyze the stereoselective reduction of K-PaOEt to(R)-PaOEt by using isopropanol as the sacrificial co-substrate to regenerate NADPH.After screening six commercially available carriers,an amino resin LXTE-700 was identified as the best solid support for the immobilization of M2 via the glutaraldehyde activation method.Upon optimization of the immobilization process and reaction conditions,the fabricated immobilized enzyme M2@amino resin demonstrated excellent recyclability and reusability,with the complete conversion of K-PaOEt to(R)-PaOEt being still realized after 12 cycles of reuse.Finally,M2@amino resin-catalyzed synthesis of(R)-PaOEt was successfully implemented in continuous-flow,accomplishing a 6.3 times higher space-time yield than that with the batch synthesis(529.2 versus 84 g L^(-1) d^(-1)).Our developed flow biocatalysis system also features an outstanding operational stability,as evidenced by the 100%conversion rate achieved after 15 consecutive days of operation.
基金supported by the National Key R&D Program of China(No.2022YFC3003502).
文摘The northern segment of the North-South Seismic Belt is characterized by intense crustal deformation,well-developed active tectonics,and frequent occurrences of strong earthquakes.Therefore,conducting a Probabilistic Seismic Hazard Analysis(PSHA)for this region is of significant importance for supporting seismic fortification in major engineering projects and formulating disaster prevention and mitigation policies.In this study,a composite seismic source model was constructed by integrating data on historical earthquakes,active faults,and paleoseismicity.Furthermore,a logic tree framework was employed to quantify epistemic uncertainties,enabling a systematic seismic hazard assessment of the region.To more accurately characterize the spatial heterogeneity of seismic activity,improvements were made to both the Circular Spatial Smoothing Model(CSSM)with a fixed radius and the Adaptive Spatial Smoothing Model(ASSM),with full consideration given to the spatiotemporal completeness of historical earthquake magnitudes.Regarding the CSSM,for scenarios involving small sample sizes in earthquake catalogs,the cross-validation method proposed in this study demonstrated higher robustness than the maximum likelihood method in determining the optimal correlation distance.Performance evaluation results indicate that while both models effectively characterize seismic activity,the ASSM exhibits superior overall predictive performance compared to the CSSM,owing to its ability to adaptively adjust the smoothing radius according to seismic density.Significant discrepancies were observed in the Peak Ground Acceleration(PGA)results calculated with a 10%probability of exceedance in 50 years across different combinations of seismic source models.The single spatially smoothed point-source model yielded a maximum PGA of approximately 0.52 g,with high-value areas concentrated near historical epicenters,thereby significantly underestimating the hazard associated with major fault zones.When combined with the simple fault-source model,the maximum PGA increased to 0.8 g,with high-value zones exhibiting a zonal distribution along faults;however,the risk remained underestimated for faults with low slip rates that are nevertheless approaching their recurrence cycles.Following the introduction of the time-dependent characteristic fault-source model,local PGA values for faults in the middle-to-late stages of their recurrence cycles increased by a factor of 2 to 7 compared to the single model.These results demonstrate that the characteristic fault-source model reasonably delineates the time-dependence of large earthquake recurrence,thereby providing a more accurate assessment of imminent seismic risks.By comprehensively applying the improved spatially smoothed pointsource model,the simple fault-source model,and the characteristic fault-source model,the following faults within the region were identified as having high seismic hazard:the Huangxianggou,Zhangxian,and Tianshui segments of the Xiqinling northern edge fault;the Maqin-Maqu segment of the Dongkunlun fault;the Longriqu fault;the Maoergai fault;the Elashan fault;the Riyueshan fault;the eastern segment of the Lenglongling fault;the Maxianshan segment of the Maxianshan northern Margin fault;and the Maomaoshan-Jinqianghe segment of the Laohushan-Maomaoshan fault.As these faults are located within seismic gaps or are approaching the recurrence periods of large earthquakes,they should be prioritized for current and future seismic monitoring as well as disaster prevention and mitigation efforts.
基金supported by the National Natural Science Foundation of China(No.52274318).
文摘A full-sectional microstructure characterization method was developed to investigate the formation of coarse slag rims during the continuous casting of hypo-peritectic steel.The cross-sectional microstructural analysis of typical slag rims for two highly crystalline powders revealed that their formation was primarily driven by the solidification of the liquid slag.Distinct differences were observed in the microstructures of slag rims from the two powders.Powder A(characterized by a higher breaking temperature and viscosity)displayed alternating lamellar microstructures of coarse and fine phases,with the coarse phases composed of akermanite-gehlenite transition phases.In contrast,powder B(with a lower breaking temperature and viscosity)predominantly comprised regular akermanite-gehlenite crystals interspersed with a certain amount of glassy phases.Numerical simulations of a three-phase fluid flow coupled with heat transfer indicate that slag rim formation correlates with mold oscillation.Solidification of the liquid slag at the slag rim front predominantly occurs during the negative stroke of the mold oscillation.The average heating rate during the ascending stage of the mold reaches approximately 100 K·s^(−1),whereas the average cooling rate during the descending stage attains 400 K·s^(−1).This temperature variation leads to the formation of lamellar microstructures,whereas the ascending stage promotes the formation of coarse structures and thicker slag rims.Based on the powder properties,two distinct formation pathways exist for highly crystalline mold powders.For the powders with a higher breaking temperature,higher viscosity,and narrower solidification range(powder A),coarse microstructures and thicker slag rims were preferentially formed.For powders with lower breaking temperature and viscosity and wider solidification ranges(powder B),the liquid slag resisted rapid solidification,and the extended mushy zone allowed the partial liquid slag to persist at the slag rim front,promoting the formation of a thin slag rim.This study enhances the understanding of slag rim formation in highly crystalline mold powders and provides critical insights into the control of longitudinal surface cracks in hypo-peritectic steel.
基金The project supported by State Key Laboratory of Structural Analyses of Industrial Equipment
文摘A concept of the independent-continuous topological variable is proposed to establish its corresponding smooth model of structural topological optimization. The method can overcome difficulties that are encountered in conventional models and algorithms for the optimization of the structural topology. Its application to truss topological optimization with stress and displacement constraints is satisfactory, with convergence faster than that of sectional optimizations.
基金This work was supported by the National Natural Science Foundation of China(Grant Number 51975449)the Key Research and Development Program of Shaanxi(Number 2021GY-309)。
文摘The contact stiffness of the joint surface directly affects the static and dynamic mechanical behavior,and accuracy of the machine tool.A new elastoplastic contact stiffness model is proposed by considering continuous and smooth contact characteristics and substrate deformation.First,the interpolation interval of cubic Hermite polynomials is improved to meet the continuous and smooth change of contact parameters during asperity deformation.Then,the micro-contact mechanism considering substrate deformation is explored by establishing an asperity-substrate system model.Furthermore,combined with statistical principles,a new contact stiffness model of the joint surface is established.Finally,the correctness of the built model is verified by comparing with experimental data and different contact models.The simulation results show that the model changes continuously and smoothly in the three deformation regions.The substrate deformation mainly affects the asperities in the elastic contact stage.The smoother is the surface,the more significant is the influence of substrate deformation.
基金Supported by the Ministerial Level Advanced Research Foundation(65822576)
文摘To improve the smoothness of motion control in a quadruped robot, a continuous and smooth gait transition method based on central pattern generator （CPG） was presented to solve the unsmooth or failed problem which may result in phase-locked or sharp point with direct replacement of the gait matrix. Through improving conventional weight matrix, a CPG network and a MATLAB/ Simulink model were constructed based on the Hopf oscillator for gait generation and transition in the quadruped robot. A co-simulation was performed using ADAMS/MATLAB for the gait transition between walk and trot to verify the correctness and effectiveness of the proposed CPG gait generation and transition algorithms. Related methods and conclusions can technically support the motion control technology of the quadruped robot.
基金Supported by the National Natural Science Foundation of ChinaFoundation of the Acadency of Electronic Science,Chinathe National Postdoctoral Science Fund of China
文摘Traditional packet switching networks have typically employed window-based congestion control schemes in order to regulate traffic flow. In ATM networks, the high speed of the communication links and the varied nature of the carried traffic make such schemes inappropriate. Therefore, simpler and more efficient schemes have to be proposed to improve the congestion control for ATM switching. This paper presents an exact performance analysis of ATM switching whose inputs consist of Continuous-Bit-Rate(CBR) and bursty traffic. The CBR traffic and bursty traffic are described by Bernoulli process and the Interrupted Bernoulli Process(IBP), respectively. Bursty traffic smoothing mechanism is analyzed. With the use of a recursive algorithm, the cell loss probability and the average delay for ATM switching of mixed CBR and bursty traffic are exactly calculated. Traffic smoothing could be implemented at a slower peak rate keeping the average rate constant or decreasing the average bursty length. Both numerical
文摘With an inequality and some analysis techniques,iterative approximation of fixed points for uniformly continuous and strongly pseudocontractive mappings in smooth Banach spaces is studied,and the recent corresponding results of Chidume are improved.
基金Supported by Yunnan Province Academician(Expert)Workstation Project,No.202305AF150097the Basic Research Program of Yunnan Province(Kunming Medical University Joint Special Project),No.202101AY070001-276+3 种基金the National Natural Science Foundation of China,No.82160159the Key Project Program of Yunnan Province(Kunming Medical University Joint Special Project),No.202301AY070001-013the Major Science and Technology Project of Yunnan Province,No.202202AA100004the Double First-class University Construction Project of Yunnan University,No.CY22624106.
文摘BACKGROUND Continuous glucose monitoring(CGM)metrics,such as time in range(TIR)and glycemic risk index(GRI),have been linked to various diabetes-related complications,including diabetic foot(DF).AIM To investigate the association between CGM-derived indicators and the risk of DF in individuals with type 2 diabetes mellitus(T2DM).METHODS A total of 591 individuals with T2DM(297 with DF and 294 without DF)were enrolled.Relevant clinical data,complications,comorbidities,hematological parameters,and 72-hour CGM data were collected.Logistic regression analysis was employed to examine the relationship between these measurements and the risk of DF.RESULTS Individuals with DF exhibited higher mean blood glucose(MBG)levels and increased proportions of time above range(TAR),TAR level 1,and TAR level 2,but lower TIR(all P<0.001).Patients with DF had significantly lower rates of achieving target ranges for TIR,TAR,and TAR level 2 than those without DF(all P<0.05).Logistic regression analysis revealed that GRI,MBG,and TAR level 1 were positively associated with DF risk,while TIR was inversely correlated(all P<0.05).Achieving TIR and TAR was inversely correlated with white blood cell count and glycated hemoglobin A1c levels(P<0.05).Additionally,achieving TAR was influenced by fasting plasma glucose,body mass index,diabetes duration,and antidiabetic medication use.CONCLUSION CGM metrics,particularly TIR and GRI,are significantly associated with the risk of DF in T2DM,emphasizing the importance of improved glucose control.
基金supported by grants from the Natural Science Foundation of Shandong Province,China(Grant Nos.:ZR2019ZD28 and ZR2022QH008)the National Natural Science Foundation of China(Grant Nos.:82270301 and 82200465)+1 种基金China Postdoctoral Science Foundation(Grant No.:2023M731842)Shandong Postdoctoral Science Foundation,China(Grant No.:SDCX-ZG-202203013).
文摘Vein graft(VG)failure(VGF)is associated with VG intimal hyperplasia,which is characterized by abnormal accumulation of vascular smooth muscle cells(VSMCs).Most neointimal VSMCs are derived from pre-existing VSMCs via a process of VSMC phenotypic transition,also known as dedifferentiation.There is increasing evidence to suggest that ginger or its bioactive ingredients may block VSMC dedifferentiation,exerting vasoprotective functions;however,the precise mechanisms have not been fully characterized.Therefore,we investigated the effect of ginger on VSMC phenotypic transition in VG remodeling after transplantation.Ginger significantly inhibited neointimal hyperplasia and promoted lumen(L)opening in a 3-month VG,which was primarily achieved by reducing ferroptotic stress.Ferroptotic stress is a pro-ferroptotic state.Contractile VSMCs did not die but instead gained a proliferative capacity and switched to the secretory type,forming neointima(NI)after vein transplantation.Ginger and its two main vasoprotective ingredients(6-gingerol and 6-shogaol)inhibit VSMC dedifferentiation by reducing ferroptotic stress.Network pharmacology analysis revealed that 6-gingerol inhibits ferroptotic stress by targeting P53,while 6-shogaol inhibits ferroptotic stress by targeting 5-lipoxygenase(Alox5),both promoting ferroptosis.Furthermore,both ingredients co-target peroxisome proliferator-activated receptor gamma(PPARγ),decreasing PPARγ-mediated nicotinamide adenine dinucleotide phosphate(NADPH)oxidase 1(Nox1)expression.Nox1 promotes intracellular reactive oxygen species(ROS)production and directly induces VSMC dedifferentiation.In addition,Nox1 is a ferroptosis-promoting gene that encourages ferroptotic stress production,indirectly leading to VSMC dedifferentiation.Ginger,a natural multi-targeted ferroptotic stress inhibitor,finely and effectively prevents VSMC phenotypic transition and protects against venous injury remodeling.
基金supported by the National Natural Science Foundation under Grant 62273189the Shandong Province Natural Science Foundation under Grant ZR2021MF005Systems Science Plus Joint Research Program of Qingdao University under Grant XT2024201 of China supporting this research work.
文摘This article investigates the anti-disturbance and stabilization problems for the nonlinear uncertain permanent magnet synchronous motor(PMSM)with stator voltage saturation and unknown load.A smooth switching mechanism is presented to structure the adaptive integral terminal sliding mode control(SMC)strategy.The control design consists of compensation control and nominal control,which improves the rapidity and accuracy of trajectory tracking.The smooth saturation model based on the error function is applied to approximate the voltage saturation phenomenon.Additionally,to deal with the adverse effects of various unknown disturbances,including model parameter uncertainties and unknown external load disturbances,an improved disturbance observer(DO)is proposed.This observer effectively suppresses the fluctuations caused by fixed gain during the starting period of the system.Finally,the experimental results under different conditions show that the proposed strategy has good tracking and disturbance suppression performances.
基金supported by the National Natural Science Foundation of China(No.52474355)the Liaoning Province Science and Technology Plan Joint Program(Key Research and Development Program Project),China(Nos.2022JH25/10200003 and 2023JH2/101800058).
文摘The application of liquid core reduction(LCR)technology in thin slab continuous casting can refine the internal microstruc-tures of slabs and improve their production efficiency.To avoid crack risks caused by large deformation during the LCR process and to minimize the thickness of the slab in bending segments,the maximum theoretical reduction amount and the corresponding reduction scheme for the LCR process must be determined.With SPA-H weathering steel as a specific research steel grade,the distributions of tem-perature and deformation fields of a slab with the LCR process were analyzed using a three-dimensional thermal-mechanical finite ele-ment model.High-temperature tensile tests were designed to determine the critical strain of corner crack propagation and intermediate crack initiation with various strain rates and temperatures,and a prediction model of the critical strain for two typical cracks,combining the effects of strain rate and temperature,was proposed by incorporating the Zener-Hollomon parameter.The crack risks with different LCR schemes were calculated using the crack risk prediction model,and the maximum theoretical reduction amount for the SPA-H slab with a transverse section of 145 mm×1600 mm was 41.8 mm,with corresponding reduction amounts for Segment 0 to Segment 4 of 15.8,7.3,6.5,6.4,and 5.8 mm,respectively.
基金supported by the National Key R&D Program of China(Grant No.2023YFC3008404)the National Key Research and Development Program,China(Grant No.2017YFD0800501)the National Natural Science Foundation of China(No.41790443).
文摘During extensive gully land consolidation projects on China's Loess Plateau,many loess-bedrock fill slopes were formed,which frequently experience shallow landslides induced by rainfall.However,studies on loess-bedrock slope failure triggered by continuous heavy rainfall are limited,and the role of the soilerock interface between the original bedrock slope and fill slope in the hydrological and failure process of the slope remains unclear.In this study,we conducted a continuous rainfall model test on a loess-bedrock fill slope.During the test,the responses of volume water content,pore pressure,micro deformation,and movement of the infiltration front were observed.The hydrological process and failure mechanism were then analysed.The findings suggest that the soilerock interface is a predominant infiltration surface within the slope.Rainfall infiltration rates at the interface reach 1.24-2.80 times those of the fill slope,with peak interfacial pore water pressure exceeding that of the loess fill.Furthermore,the infiltration front moves rapidly along the interface toward the bottom of the slope,reducing interfacial cohesion between bedrock and loess.The slope failure modes are summarised into three phases:local failure→flow slide and crack penetration→multistage block retrogressive slides.The cracks generated at the slope surface serve as key determinants of the geometry and scale of shallow landslides.Therefore,we recommend targeted engineering interventions to mitigate the instability and erosion of loessebedrock fill slopes.
基金supported by the National Key Research and Development Program of China (Grant No.2022YFB3706801)the National Natural Science Foundation of China (Grant Nos.U2341253,52371019,U2241232)+2 种基金the Dalian High-level Talents Innovation Support Program (Grant No.2021RD06)the Applied Basic Research Program of Liaoning Province (Grant No.2022JH2/101300003)the Natural Science Foundation of Liaoning Province (Grant Nos.2022-BS-262,JYTMS20230031)。
文摘Based on thermodynamic calculations and continuous rheological extrusion(CRE)technology,Al-Ti-V-B master alloys were designed and prepared.The morphology and the distribution of the refined phases in the master alloys were analyzed by XRD,SEM,and TEM.The effects of master alloy addition and holding time on the microstructure and mechanical properties of A356 alloy were investigated.Under the optimum refiner addition of 0.3wt.%and the holding time of 20 min,the average grain size of the refined A356 alloy is 151.8±9.11μm,89.62%lower than that of original A356 alloy.The tensile strength and elongation of as-cast A356refined alloy are 196.11 MPa and 5.75%,respectively.After T6 treatment,the tensile strength and elongation of A356 refined alloy are 290.1 MPa and 3.09%,respectively.The fracture morphology is characterized by a predominance of along-crystal fracture with a small amount of through-crystal fracture,attributed to the refined grains.Finer grains promote crack path deflection and localized plastic deformation,enhancing energy dissipation and reducing the tendency for brittle fracture.This study provides a novel approach to improving the mechanical properties of A356 alloy through grain refinement using CRE Al-Ti-V-B master alloy.
基金supported by National Key Research and Development Program of China(Grant No.2023YFB4604100)National Key Research and Development Program of China(Grant No.2022YFB3806104)+4 种基金Key Research and Development Program in Shaanxi Province(Grant No.2021LLRH-08-17)Young Elite Scientists Sponsorship Program by CAST(No.2023QNRC001)K C Wong Education Foundation of ChinaYouth Innovation Team of Shaanxi Universities of ChinaKey Research and Development Program of Shaanxi Province(Grant 2021LLRH-08-3.1).
文摘Ensuring the consistent mechanical performance of three-dimensional(3D)-printed continuous fiber-reinforced composites is a significant challenge in additive manufacturing.The current reliance on manual monitoring exacerbates this challenge by rendering the process vulnerable to environmental changes and unexpected factors,resulting in defects and inconsistent product quality,particularly in unmanned long-term operations or printing in extreme environments.To address these issues,we developed a process monitoring and closed-loop feedback control strategy for the 3D printing process.Real-time printing image data were captured and analyzed using a well-trained neural network model,and a real-time control module-enabled closed-loop feedback control of the flow rate was developed.The neural network model,which was based on image processing and artificial intelligence,enabled the recognition of flow rate values with an accuracy of 94.70%.The experimental results showed significant improvements in both the surface performance and mechanical properties of printed composites,with three to six times improvement in tensile strength and elastic modulus,demonstrating the effectiveness of the strategy.This study provides a generalized process monitoring and feedback control method for the 3D printing of continuous fiber-reinforced composites,and offers a potential solution for remote online monitoring and closed-loop adjustment in unmanned or extreme space environments.
基金Supported by NSFC (No.12031006)Fundamental Research Funds for the Central Universities of China。
文摘We study the Cauchy problem of the Kolmogorov-Fokker-Planck equations and show that the solution enjoys an analytic smoothing effect with L?initial datum for positive time.
