Catalyst–Support Interaction in Polyaniline‑Supported Ni_(3)Fe Oxide to Boost Oxygen Evolution Activities for Rechargeable Zn‑Air Batteries

Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe oxide.It is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe oxide.Considering the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.

Tuning support morphology to control alloy over PtCo/γ-Al_(2)O_(3) for the preferential oxidation of CO

The preferential oxidation of CO(CO-PROX)reaction is a cost-effective method for eliminating trace amounts of CO from the fuel H2.Pt-based catalysts have been extensively studied for COPROX,with their activity influenced by the morphology of the support.Hydrothermal synthesis was employed to produce different morphologies ofγ-Al_(2)O_(3):flower-likeγ-Al_(2)O_(3)(f)exposing(110)crystal faces,sheet-likeγ-Al_(2)O_(3)(s)revealing(100)crystal faces,and rod-likeγ-Al_(2)O_(3)(r)displaying(111)crystal faces,followed by loading PtCo nanoparticles.The exposed crystal faces of the support impact the alloying degree of the PtCo nanoparticles,and an increase in the alloying degree correlates with enhanced catalyst reactivity.Pt_(3)Co intermetallic compounds were identified onγ-Al_(2)O_(3)(f)exposing(110)crystal faces,and PtCo/γ-Al_(2)O_(3)(f)showed high catalytic activity in the CO-PROX reaction,achieving 100%CO conversion across a broad temperature range of 50−225°C.In contrast,only partial alloying of PtCo was observed onγ-Al_(2)O_(3)(s).Furthermore,no alloying between Pt and Co occurred in PtCo/γ-Al_(2)O_(3)(r),resulting in a reaction rate at 50°C that was merely 11%of that of PtCo/γ-Al_(2)O_(3)(f).The formation of Pt3Co intermetallic compounds led to a more oxidized state of Pt,which significantly diminished the adsorption of CO on Pt and augmented the active oxygen species,thereby facilitating the selective oxidation of CO.

Design of insulation support system of 120 keV positive ion source accelerator

In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion source.Through the finite element analysis method,the electrostatic analyses of insulators and grid plates were carried out,the material and structure parameters of insulators were determined.The maximum electric field around each insulator is about 4 kV/mm,and the maximum electric field between grids is about 14 kV/mm,which can meet the 120 keV withstand voltage holding.The insulation system for the positive ion source accelerator with 120 keV is designed,and the connection and basic parameters of insulators and support flanges are analyzed and determined.

Comprehensive influence of individualized nutrition support and nursing strategy on rehabilitation of patients with liver cancer after operation

BACKGROUND Hepatocellular carcinoma ranks among the most prevalent malignant neoplasms.Surgical intervention constitutes a critical therapeutic approach for this condition.Nonetheless,postoperative recovery is frequently influenced by the patient's nutritional status and the quality of nursing care provided.AIM To examine the comprehensive impact of personalized nutritional support and nursing strategies on the postoperative rehabilitation of patients with liver cancer.METHODS In this study,a retrospective comparative analysis was conducted involving 60 post-operative liver cancer patients.The subjects were selected as subjects and divided into two groups based on differing nursing interventions,with each group comprising 30 patients.The control group received standard nutritional support and care,whereas the experimental group received individualized nutritional support and nursing strategies.The study aimed to evaluate the impact of individualized nutrition by comparing the rehabilitation indices,nutritional status,quality of life(QoL),and complication rates between the two groups.RESULTS The results showed that the recovery index of the experimental group was significantly better than that of the control group 2 weeks after surgery,and the average liver function recovery index of the experimental group was 85.significantly higher than that of the control group(73.67±7.19).In terms of nutritional status,the serum albumin level and body weight stabilization rate of the experimental group were also significantly higher than those of the control group,which were 42.33±2.4 g/L and 93.3%,respectively,compared with 36.01±3.85 g/L and 76.7%of the control group.In addition,the average QoL score of the experimental group was 84.66±3.7 points,which was significantly higher than that of the control group(70.92±4.28 points).At the psychological level,the average anxiety score of the experimental group was 1.17±0.29,and the average depression score was 1.47±0.4,which were significantly lower than the 2.26±0.42 and 2.57±0.45 of the control group.This showed that patients in the experimental group were better relieved of anxiety and depression under the individualized nutrition support and nursing strategy.More importantly,the complication rate in the experimental group was only 10%,much lower than the 33.3%in the control group.CONCLUSION Personalized nutritional support and tailored nursing strategies significantly enhance the postoperative rehabilitation of liver cancer patients.Consequently,it is recommended to implement and advocate for these individualized approaches to improve both the recovery outcomes and QoL for these patients.

Influence of quasi-electrostatic support on amplification of space charge waves in amplification section of a superheterodyne free electron laser

A theoretical study of the influence of a quasi-electrostatic support on the amplification level of the slow space charge wave(SCW) in the amplification section of a superheterodyne free electron laser(FEL) was carried out. One of the ways to significantly increase the saturation level of the slow SCW is maintaining the conditions of a three-wave parametric resonance between the slow, fast SCWs and the resulting pump electric field. This can be done by introducing the quasielectrostatic support in the superheterodyne FEL amplification section. Also, it was found that the generated pump electric field significantly influences the maintenance of parametric resonance conditions. As a result, this increases the saturation level of the slow SCW by 70%. Finally, the quasi-electrostatic support significantly reduces the maximum value of the electrostatic undulator pump field strength, which is necessary to achieve the maximum saturation level of the slow SCW.

Perceived Social Support and Symptoms of Depression and Anxiety among Chinese Adolescents:A Moderated Chain Mediation Model

Background:Although previous studies indicate that perceived social support might be associated with adolescent psychological problems,the specific mechanism has not been thoroughly discussed.Based on theoretical and empirical research on problematic Internet use(PIU)and sleep quality,this study explored whether they play a mediating role between perceived social support and symptoms of depression and anxiety among adolescents.Furthermore,we investigated whether these relationships varied by place of residence.Methods:A sample of 2115 Chinese adolescents was included,and analyzed data related to perceived social support,PIU,sleep quality,symptoms of depression and anxiety,and sociodemographic variables.Correlation analysis,mediation,and moderation analysis were mainly used.Results:Perceived social support was negatively correlated with depressive symptoms(r=−0.22,p<0.001)and anxiety symptoms(r=−0.20,p<0.001)among adolescents.PIU and sleep quality played a chain mediating role in the relationship between perceived social support and symptoms of depression and anxiety in adolescents.Additionally,the place of residence moderated the relationships between perceived social support and PIU and symptoms of depression and anxiety.Perceived social support was a significant negative predictor of PIU and symptoms of depression and anxiety among adolescents in urban areas but not in rural areas.Conclusion:The findings suggest that low levels of perceived social support may lead to more PIU and poorer sleep quality,which may further increase the risk of symptoms of depression and anxiety in adolescents,especially in urban areas.

Seismic design of variable cross-section damped steel support frame for post equipment

High-voltage electrical post equipment is generally installed on steel supports,which amplifies the seismic inputs and degrades the seismic performance of equipment.This study proposed a variable cross-section damped steel support frame(VCDFS)with viscous dampers to reduce seismic responses of both tall and low-rise electrical equipment.The VCDFS contains a trapezoidal damper layer to generate rocking motions,enabling the diagonal viscous dampers to dissipate seismic inputs.A theoretical model of post equipment with VCDFS is established,and an optimal design procedure is proposed.The analysis shows that the remaining static stiffness ratio λ_(k) is the key parameter that determines the effectiveness of the VCDFS.The VCDFS reduces the average displacement and stress response of a post insulator by 39.4%and 44.6%,respectively,together with a significant decrease in the dynamic amplification factor.Therefore,it is recommended to use the VCDFS instead of the conventional latticed-steel frame in earthquake zones.

Correlation between psychological,family social support,and home nursing quality for an implanted venous access port

BACKGROUND Cancer patients with an implanted venous access port(IVAP)often manage their care at home during chemotherapy intervals,including maintaining the device,monitoring complications,and following medication instructions.Home care ensures continued support after discharge.However,due to factors such as age,gender,culture,psychological status,and family support,the quality of home care varies significantly.Understanding these factors can help provide targeted guidance to improve the care of cancer patients.AIM To explore IVAP chemotherapy on home care quality and its association with mental health and family support for cancer patients.METHODS This investigative study was based on a medical records system.It investigated the relationship between psychological status,family support,and home care quality in 180 patients with cancer undergoing IVAP chemotherapy.Psychological status was assessed using the State Anxiety Inventory(S-AI);family support was assessed using the Perceived Social Support Scale(PSSS),and home care quality was evaluated using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire(EORTC QLQ-C30).Pearson’s correlation and Structural Equation Modeling were used to analyze the interplay between these factors.RESULTS The average S-AI score was 47.52±14.47,PSSS was 52.48±12.64,and EORTC QLQ-C30 was 70.09±17.32.A substantial inverse relationship was observed between the EORTC QLQ-C30 and S-AI scores(r=-0.712).A significant positive correlation was found between the EORTC QLQ-C30 and the PSSS,with a correlation coefficient of(r=0.744).The multiple linear regression analysis indicated that family social support,psychological status,and average monthly family income were the main factors influencing the variation in the quality of home care,explaining 71.9%of the variation.The Structural Equation Modeling results indicated that psychological status acted as a partial mediator in the association between family social support and home care quality of life,explaining 32.78%of the mediation effect.CONCLUSION Psychological status and family social support positively impacted cancer patients’home care quality,with psychology partially mediating this effect.

Deformation mechanism and NPR anchor cable truss coupling support in tunnel through fault fracture zone

To address the issue of extensive deformation in the Tabaiyi Tunnel caused by the fault zone,nuclear magnetic resonance(NMR)technology was employed to analyze the physical and mechanical properties of waterabsorbing mudstone.This analysis aimed to understand the mechanism behind the significant deformations.Drawing from the principle of excavation stress compensation,a support scheme featuring NPR anchorcables and an asymmetric truss support system was devised.To validate the scheme,numerical analysis using a combination of the Discrete Element Method(DEM)-Finite Element Method(FEM)was conducted.Additionally,similar material model tests and engineering measurements were carried out.Field experiments were also performed to evaluate the NPR anchor-cable and truss support system,focusing on anchor cable forces,pressures between the truss and surrounding rock,pressures between the initial support and secondary lining,as well as the magnitude of settlement and convergence deformation in the surrounding rock.The results indicate that the waterinduced expansion of clay minerals,resulting from damage caused by fissure water,accelerated the softening of the mudstone's internal structure,leading to significant deformations in the Tabaiyi Tunnel under high tectonic stress.The original support design fell short as the length of the anchor rods was smaller than the expansion depth of the plastic zone.As a result,the initial support structure bore the entire load from the surrounding rock,and a non-coupled deformation contact was observed between the double-arch truss and the surrounding rock.The adoption of NPR asymmetric anchor-cable support effectively restrained the expansion and asymmetric distribution characteristics of the plastic zone.Considering the mechanical degradation caused by water absorption in mudstone,the rigid constraint provided by the truss proved crucial for controlling the stability of the surrounding rock.These research findings hold significant implications for managing large deformations in soft rock tunnels situated within fractured zones under high tectonic stress conditions.

Extracorporeal organ support for critically ill patients:Overcoming the past,achieving the maximum at present,and redefining the future

Extracorporeal organ support(ECOS)has made remarkable progress over the last few years.Renal replacement therapy,introduced a few decades ago,was the first available application of ECOS.The subsequent evolution of ECOS enabled the enhanced support to many other organs,including the heart[veno-arterial extracorporeal membrane oxygenation(ECMO),slow continuous ultrafiltration],the lungs(veno-venous ECMO,extracorporeal carbon dioxide removal),and the liver(blood purification techniques for the detoxification of liver toxins).Moreover,additional indications of these methods,including the suppression of excessive inflammatory response occurring in severe disorders such as sepsis,coronavirus disease 2019,pancreatitis,and trauma(blood purification techniques for the removal of exotoxins,endotoxins,or cytokines),have arisen.Multiple organ support therapy is crucial since a vast majority of critically ill patients present not with a single but with multiple organ failure(MOF),whereas,traditional therapeutic approaches(mechanical ventilation for acute respiratory failure,antibiotics for sepsis,and inotropes for cardiac dysfunction)have reached the maximum efficacy and cannot be improved further.However,several issues remain to be clarified,such as the complexity and cost of ECOS systems,standardization of indications,therapeutic protocols and initiation time,choice of the patients who will benefit most from these interventions,while evidence from randomized controlled trials supporting their use is still limited.Nevertheless,these methods are currently a part of routine clinical practice in intensive care units.This editorial presents the past,present,and future considerations,as well as perspectives regarding these therapies.Our better understanding of these methods,the pathophysiology of MOF,the crosstalk between native organs resulting in MOF,and the crosstalk between native organs and artificial organ support systems when applied sequentially or simultaneously,will lead to the multiplication of their effects and the minimization of complications arising from their use.

Least Squares One-Class Support Tensor Machine

One-class classification problem has become a popular problem in many fields, with a wide range of applications in anomaly detection, fault diagnosis, and face recognition. We investigate the one-class classification problem for second-order tensor data. Traditional vector-based one-class classification methods such as one-class support vector machine (OCSVM) and least squares one-class support vector machine (LSOCSVM) have limitations when tensor is used as input data, so we propose a new tensor one-class classification method, LSOCSTM, which directly uses tensor as input data. On one hand, using tensor as input data not only enables to classify tensor data, but also for vector data, classifying it after high dimensionalizing it into tensor still improves the classification accuracy and overcomes the over-fitting problem. On the other hand, different from one-class support tensor machine (OCSTM), we use squared loss instead of the original loss function so that we solve a series of linear equations instead of quadratic programming problems. Therefore, we use the distance to the hyperplane as a metric for classification, and the proposed method is more accurate and faster compared to existing methods. The experimental results show the high efficiency of the proposed method compared with several state-of-the-art methods.

Application Strategies of Shotcrete Anchor Support Technology in Highway Bridge and Tunnel Engineering

This article analyzes the application strategies of shotcrete anchor support technology using a highway bridge-tunnel construction project as an example.The article covers various strategies,including support plan formulation,mortar shotcrete anchor construction,grid steel frame construction,steel mesh construction,and concrete support construction.This analysis aims to provide a guideline for those interested in applying this technology and improving the quality and safety of highway bridges and tunnels construction.

Stability analysis of longwall top-coal caving face in extra-thick coal seams based on an innovative numerical hydraulic support model

The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working conditions.Based on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were researched.Firstly,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution characteristics.The influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure area.Thirdly,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal.

Selective hydrogenation of dimethyl toluene-2,4-dicarbamate over supported Rh-based catalysts:Effect of support properties

The selective hydrogenation of dimethyl toluene-2,4-dicarbamate(TDC)to methyl cyclohexyl-2,4-dicarbamate(also called hydrogenated TDC,HTDC)is an essential process for non-phosgene synthesis of methylcyclohexane-2,4-diisocyanate.Herein,we prepared a series of supported Rh-based catalysts by the excessive impregnation method and investigated their catalytic performance for the selective hydrogenation of TDC.The emphasis was put on the influence of support properties on the catalytic performance.Among the prepared catalysts,Rh/g-Al_(2)O_(3)performed the best:a HTDC yield of 88.4%was achieved with a 100%conversion of TDC under the conditions of 100℃,3 MPa and 1 h.Furthermore,Rh/γ-Al_(2)O_(3)could be repetitively used for 4 times without a significant loss of its catalytic activity.TEM,XRD,N_(2)adsorption-desorption,H_(2)-TPR,NH_(3)/CO_(2)-TPD,XPS and ICP characterizations were employed to distinguish the properties of the prepared catalysts and the results were correlated with their catalytic performance.It is indicated that the yield of HTDC shows a positive relevance with the percentage of moderate-to-strong acid sites and the content of Rh^(n+)(n≥3)in the catalysts.High values of the percentage and the content can promote a strong interaction between Rh nanoparticles and the supports,facilitating both the transfer of electrons from Rh to the support and the formation of Rh^(n+)species.This is conducive to activating the benzene ring of TDC and thereby improving the yield of HTDC.

Perspectives and Challenges of Family Members in Providing Mental Support to Cancer Patients:A Qualitative Study in Beijing,China

This study explores the perspectives and challenges faced by family members providing mental support to cancer patients in Beijing,China.The primary objective is to understand the emotional and practical roles family members undertake and the difficulties they encounter.Utilizing a qualitative research design,data were collected through semi-structured interviews with family caregivers of cancer patients.Thematic analysis revealed several key themes:the dual burden of emotional support and caregiving responsibilities,the impact on daily life and personal well-being,the role and effectiveness of external support systems,perceptions of medical staff support,and the common challenges and conflicts faced in caregiving.The findings highlight the critical need for comprehensive support systems that address both the emotional and practical needs of family caregivers.Recommendations for enhancing family-centered support programs in oncology settings are discussed.

Confined cobalt single-atom catalysts with strong electronic metal-support interactions based on a biomimetic self-assembly strategy

Designing high-performance and low-cost electrocatalysts for oxygen evolu-tion reaction(OER)is critical for the conversion and storage of sustainable energy technologies.Inspired by the biomineralization process,we utilized the phosphorylation sites of collagen molecules to combine with cobalt-based mononuclear precursors at the molecular level and built a three-dimensional(3D)porous hierarchical material through a bottom-up biomimetic self-assembly strategy to obtain single-atom catalysts confined on carbonized biomimetic self-assembled carriers(Co SACs/cBSC)after subsequent high-temperature annealing.In this strategy,the biomolecule improved the anchoring efficiency of the metal precursor through precise functional groups;meanwhile,the binding-then-assembling strategy also effectively suppressed the nonspecific adsorption of metal ions,ultimately preventing atomic agglomeration and achieving strong electronic metal-support interactions(EMSIs).Experimental characterizations confirm that binding forms between cobalt metal and carbonized self-assembled substrate(Co–O_(4)–P).Theoretical calculations disclose that the local environment changes significantly tailored the Co d-band center,and optimized the binding energy of oxygenated intermediates and the energy barrier of oxygen release.As a result,the obtained Co SACs/cBSC catalyst can achieve remarkable OER activity and 24 h durability in 1 M KOH(η_(10) at 288 mV;Tafel slope of 44 mV dec^(-1)),better than other transition metal-based catalysts and commercial IrO_(2).Overall,we presented a self-assembly strategy to prepare transition metal SACs with strong EMSIs,providing a new avenue for the preparation of efficient catalysts with fine atomic structures.

Analysis of the interaction between bolt-reinforced rock and surface support in tunnels based on convergence-confinement method

To investigate the interaction of the bolt-reinforced rock and the surface support,an analytical model of the convergence-confinement type is proposed,considering the sequential installation of the fully grouted rockbolts and the surface support.The rock mass is assumed to be elastic-brittle-plastic material,obeying the linear Mohr-Coulomb criterion or the non-linear Hoek-Brown criterion.According to the strain states of the tunnel wall at bolt and surface support installation and the relative magnitude between the bolt length and the plastic depth during the whole process,six cases are categorized upon solving the problem.Each case is divided into three stages due to the different effects of the active rockbolts and the passive surface support.The fictitious pressure is introduced to quantify the threedimensional(3D)effect of the tunnel face,and thus,the actual physical location along the tunnel axis of the analytical section can be considered.By using the bolt-rock strain compatibility and the rocksurface support displacement compatibility conditions,the solutions of longitudinal tunnel displacement and the reaction pressure of surface support along the tunnel axis are obtained.The proposed analytical solutions are validated by a series of 3D numerical simulations.Extensive parametric studies are conducted to examine the effect of the typical parameters of rockbolts and surface support on the tunnel displacement and the reaction pressure of the surface support under different rock conditions.The results show that the rockbolts are more effective in controlling the tunnel displacement than the surface support,which should be installed as soon as possible with a suitable length.For tunnels excavated in weak rocks or with restricted displacement control requirements,the surface support should also be installed or closed timely with a certain stiffness.The proposed method provides a convenient alternative approach for the optimization of rockbolts and surface support at the preliminary stage of tunnel design.

Dysfunctional attitudes,social support,negative life events,and depressive symptoms in Chinese adolescents:A moderated mediation model

BACKGROUND Depression is a prevalent psychological issue in adolescents that is significantly related to negative life events(NLEs)and dysfunctional attitudes.High levels of social support can significantly buffer NLEs’effect on depression.Currently,there is limited research on how social support moderates the relationship between NLEs,dysfunctional attitudes,and depression in adolescents in China.It is imperative to investigate this moderating effect to mitigate dysfunctional attitudes in adolescent undergoing depressive mood,ultimately enhancing their overall mental health.AIM To investigate the relationship and underlying mechanisms between specific dysfunctional attitudes,social support,and depression among Chinese adolescents.METHODS This is a cross-sectional study which selected five middle schools in Shandong Province for investigation in March 2022.Participants included 795 adolescents(49.87%male,mage=15.15,SD=1.84,age range=11-18 years old).All participants completed the Dysfunctional Attitude Scale,Adolescent Life Event Scale,Beck Depression Inventory,and Social Support Rating Scale.A moderated mediation model was conducted to examine the relationship between specific dysfunctional attitudes,social support,and depression.RESULTS Results indicated that NLEs affected depression through the mediating role of specific dysfunctional attitudes(autonomy attitudesβ=0.21;perfectionismβ=0.25).Moreover,social support was found to moderate the mediating effect between NLEs,specific dysfunctional attitudes,and depressive symptoms(autonomy attitudes b2=-0.08;perfectionism b2=-0.09).CONCLUSION Dysfunctional attitudes mediated and social support moderated the relationship between NLEs and depression.Social support can buffer depression symptoms among adolescents with autonomy attitudes and perfectionism.

Mechanism of high-preload support based on the NPR anchor cable in layered soft rock tunnels

The control of large deformation problems in layered soft rock tunnels needs to solve urgently.The roof problem is particularly severe among the deformation issues in tunnels.This study first analyzes the asymmetric deformation modes in layered soft rock tunnels with large deformations.Subsequently,we construct a mechanical model under ideal conditions for controlling the roof of layered soft rock tunnels through high preload with the support of NPR anchor cables.The prominent roles of long and short NPR anchor cables in the support system are also analyzed.The results indicate the significance of high preload in controlling the roof of layered soft rock tunnels.The short NPR anchor cables effectively improve the integrity of the stratified soft rock layers,while the long NPR anchor cables effectively mobilize the self-bearing capacity of deep-stable rock layers.Finally,the high-preload support method with NPR anchor cables is validated to have a good effect on controlling large deformations in layered soft rock tunnels through field monitoring data.

Comparison of debris flow susceptibility assessment methods:support vector machine,particle swarm optimization,and feature selection techniques

The selection of important factors in machine learning-based susceptibility assessments is crucial to obtain reliable susceptibility results.In this study,metaheuristic optimization and feature selection techniques were applied to identify the most important input parameters for mapping debris flow susceptibility in the southern mountain area of Chengde City in Hebei Province,China,by using machine learning algorithms.In total,133 historical debris flow records and 16 related factors were selected.The support vector machine(SVM)was first used as the base classifier,and then a hybrid model was introduced by a two-step process.First,the particle swarm optimization(PSO)algorithm was employed to select the SVM model hyperparameters.Second,two feature selection algorithms,namely principal component analysis(PCA)and PSO,were integrated into the PSO-based SVM model,which generated the PCA-PSO-SVM and FS-PSO-SVM models,respectively.Three statistical metrics(accuracy,recall,and specificity)and the area under the receiver operating characteristic curve(AUC)were employed to evaluate and validate the performance of the models.The results indicated that the feature selection-based models exhibited the best performance,followed by the PSO-based SVM and SVM models.Moreover,the performance of the FS-PSO-SVM model was better than that of the PCA-PSO-SVM model,showing the highest AUC,accuracy,recall,and specificity values in both the training and testing processes.It was found that the selection of optimal features is crucial to improving the reliability of debris flow susceptibility assessment results.Moreover,the PSO algorithm was found to be not only an effective tool for hyperparameter optimization,but also a useful feature selection algorithm to improve prediction accuracies of debris flow susceptibility by using machine learning algorithms.The high and very high debris flow susceptibility zone appropriately covers 38.01%of the study area,where debris flow may occur under intensive human activities and heavy rainfall events.