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Sensor selection of helicopter transmission systems based on physical model and sensitivity analysis

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Chinese Journal of Aeronautics 2014年第3期27卷 643-654页

作者： Lyu Kehong Tan Xiaodong Liu Guanjun zhao chenxu Science and Technology on Integrated Logistics Support Laboratory National University of Defense Technology Department of Electronic Technology Officer’s College of CAPF

In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on physical model and sensitivity analysis. Firstly, a physical model of tooth damage and mesh stiffness is built. Secondly, some effective condition indicators （Cls） are presented, and the optimal Cls set is selected by comparing their test statistics according to Mann-Kendall test. Afterwards, the selected CIs are used to generate a health indicator （HI） through sen slop estimator. Then, the sensors are selected according to the monotonic relevance and sensitivity to the damage levels. Finally, the proposed method is verified by the simulation and experimental data. The results show that the approach can provide a guide for health monitor- ing of helicopter transmission systems, and it is effective to reduce the test cost and improve the system＇s reliability.

关键词： Condition indicators Health indicator Helicopter transmissionsystems Mann-Kendall test Physical model Sensitivity analysis Sen slop estimator Sensor selection

CO adsorption on metal doped 2D InSe:Mechanism and application

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Progress in Natural Science:Materials International 2019年第3期29卷 305-309页

作者： chenxu zhao Wang Gao Qing Jiang Key Laboratory of Automobile Materials Ministry of EducationDepartment of Materials Science and EngineeringJilin University

A novel-type material based on metal doped 2D InSe (M@2DInSe) has been proposed for CO *** results reveal that the conventional Blyholder mechanism can be applicable to M@2DInSe systems,and the charge transfer between CO and M@2DInSe can serve as an effective measurement for the adsorption energy of *** M@2DInSe,the response of electronic structures towards CO adsorption is also strongly correlated with the adsorption energy of CO,demonstrating an apparent metal-to-insulator transition for Fe@2DInSe and Mo@2DInSe under the influence of CO *** findings provide a new material-design scheme to detect CO molecules and promising candidates for further experimental studies.

关键词： Se CO adsorption on metal doped 2D InSe:Mechanism and application

Turning the V site in V@2D-BC_(3)N_(2)complex to high curvature state for efficient CO_(2)electroreduction to hydrocarbons

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Chinese Chemical Letters 2023年第8期34卷 328-332页

作者： Chaozheng He Yue Yu chenxu zhao Jinrong Huo Institute of Environmental and Energy Catalysis School of Materials Science and Chemical EngineeringXi’an Technological UniversityXi’an 710021China School of Sciences Xi’an Technological UniversityXi’an 710021China

Hydrocarbons are promising products for CO_(2)electroreduction(CRR)while is impeded by the low *** the curvature of the active site is an effective strategy to change the adsorption properties and further regulate the product distribution and ***,we have designed a novel V single atom catalyst(SAC)based on rolled two-dimensional(2D)BC_(3)N_(2)substrate with different *** results have demonstrated that increased curvature can enhance the adsorption strength of CRR intermediates,which follows different mechanisms for systems with low and high *** character eventually leads to the deviation away from the scaling line between Ead[CO]∼Ead[COOH]based on transition metals for V@2D-BC_(3)N_(2)systems.3-3 system is screened as the optimal candidate for hydrocarbons production due to the enhanced binding ability of adsorbates,which can increase the reactivity for hydrocarbons production and hinder the production of H2 and HCOOH simultaneously.

关键词： V doped 2D BC_(3)N_(2) Curvature effect CO_(2)electroreduction Hydrocarbons production d-band center theory Geometric and electronic properties

Hydrogen generation of ammonia borane hydrolysis catalyzed by Fe_(22)@Co_(58) core-shell structure

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Chinese Chemical Letters 2021年第7期32卷 2269-2273页

作者： Jinrong Huo Ling Fu chenxu zhao Chaozheng He School of Sciences Xi'an Technological UniversityXi'an 710021China Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices School of Materials Science and Chemical EngineeringXi'an Technological UniversityXi'an 710021China Institute of Environmental and Energy Catalysis School of Materials Science and Chemical EngineeringXi'an Technological University.Xi'an 710021China College of Resources and Environmental Engineering Tianshui Normal UniversityTianshui 741001China

In this paper,the process of ammonia borane(AB)hydrolysis generate H_(2) on the transition metal Fe@Co core-shell structure has been *** to the different roles played by H_(2)O molecules and the number of H_(2)O molecules involved,there are three schemes of reaction ***Ⅰdoes not involve the dissociation of H_(2)O molecules and all H atoms come from ***,the H_(2)O molecule has no effect on the breaking of the B—H bond or the N—H *** reaction absorbs more heat during the formation of the second and third H_(2) ***Ⅱincludes the dissociation of H_(2)O molecules and the cleavage of B—H or N—H bonds,respectively,and the reaction shows a slight ***Ⅲstarted from the break of the B—N bond and obtained 3H_(2) molecules through the participation of different numbers of H_(2)O *** multiple comparative analyses,the optimal hydrolysis reaction path has been obtained,and the reaction process can proceed spontaneously at room temperature.

关键词： Fe_(22)@Co_(58)core-shell Hydrolysis reaction Catalyst Ammonia borane Hydrogen generation

Computational design of BC_(3)N_(2) based single atom catalyst for dramatic activation of inert CO_(2) and CH4 gasses into CH_(3)COOH with ultralow CH_(4) dissociation barrier

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Chinese Chemical Letters 2023年第1期34卷 493-498页

作者： chenxu zhao Menghui Xi Jinrong Huo Chaozheng He Ling Fu Institute of Environment and Energy Catalysis School of Materials Science and Chemical EngineeringXi’an Technological UniversityXi’an 710021China School of Sciences Xi’an Technological UniversityXi’an 710021China College of Resources and Environmental Engineering Tianshui Normal UniversityTianshui 741001China

The production of CH_(3)COOH from CO_(2)and CH_(4) has stimulated much interest due to the high energy density of C2 *** kinds of catalysts have been developed while the high dissociation barrier of CH_(4) and low selectivity still hinders the efficiency of the *** have herein proposed a novel catalyst with single metals loaded on 2D BC_(3)N_(2) substrate(M@2D-BC_(3)N_(2))based on density functional *** numerous candidates,Pt@2D-BC_(3)N_(2) possesses the most favorable reactivity with an ultralow barrier of CH_(4) splitting(0.26 e V),which is due to the efficient capture ability of CH_(4) on Pt ***,the selectivity for CH_(3)COOH is also very high,which mainly stems from the unique electronic properties of molecules and substrate:The degenerated states,including s,px,pyand pz,in CO_(2)reflects the existence of delocalizedπbonds between C and *** can interact with states of Pt(s),Pt(pz),Pt(dxz),Pt(dyz),and Pt(z2)in Pt@2D-BC_(3)N_(2).The kinetics model also proves that our system can promote CH_(3)COOH production via simply increasing the temperature or the coverage of CH_(4) and CO_(2).Our results provide a reasonable illustration in clarifying mechanism and propose promising candidates with high reactivity for further study.

关键词： Density functional theory CO_(2)/CH4 coactivation 2D BC_(3)N_(2)substrate CH_(3)COOH production

Associative vs. dissociative mechanism: Electrocatalysis of nitric oxide to ammonia

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Chinese Chemical Letters 2022年第2期33卷 1051-1057页

作者： Chaozheng He Jia Wang Ling Fu chenxu zhao Jinrong Huo Institute of Environment and Energy Catalysis Shaanxi Key Laboratory of Optoelectronic Functional Materials and DevicesSchool of Materials Science and Chemical EngineeringXi’an Technological UniversityXi’an 710021China College of Resources and Environmental Engineering Tianshui Normal UniversityTianshui 741001China School of Sciences Xi’an Technological UniversityXi’an 710021China

Nitric oxide reduction to ammonia by electrocatalysis is the potential application in the elimination of smog and energy conversion. In this work, the feasibility of the application of two-dimensional metal borides(MBenes) in nitric oxide electroreduction reaction(NOER) was investigated through density functional theory calculations. Including the geometry and electronic structure of five kinds of MBenes, the adsorption of NO on the surface of these substrates, the selective adsorption of hydrogen protons during the hydrogenation process, and the overpotential in the electrocatalytic ammonia synthesis process. As a result, Mn B exhibited the most favorable catalytic performance according to the associative pathways,which is thermodynamically performed spontaneously, and WB has a minimum overpotential of 0.37 V vs. RHE in the process of ammonia production according to the dissociative pathway. Overall, our work is the first to explore the electrocatalytic NO through the dissociative mechanism to synthesize ammonia in-depth and proves that MBenes are efficient NO electrocatalytic ammonia synthesis catalysts. These research results provide a new direction for the development of electrocatalytic ammonia synthesis experimentally and theoretically.

关键词： MBenes Nitric oxide NOER First-principles calculation Ammonia

Highly active Fe_(36)Co_(44) bimetallic nanoclusters catalysts for hydrolysis of ammonia borane: The first-principles study

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Chinese Chemical Letters 2023年第2期34卷 550-556页

作者： Jinrong Huo Haocong Wei Ling Fu chenxu zhao Chaozheng He School of Sciences Xi'an Technological UniversityXi'an 710021China Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices School of Materials Science and Chemical EngineeringXi'an Technological UniversityXi'an 710021China Institute of Environmental and Energy Catalysis School of Materials Science and Chemical EngineeringXi'an Technological UniversityXi'an 710021China College of Resources and Environmental Engineering Tianshui Normal UniversityTianshui 741001China

In this paper,Fe_(36)Co_(44)nanocluster structure is used to catalyze the hydrolysis reaction of ammonia borane to produce H_(2).Firstly,we complete the construction of Fe_(36)Co_(44)cluster structure and calculate the electronic properties of the *** comparing the adsorption process of Ammonia Borane (AB) in active sites of the cluster,which have different Effective Coordination Number (ECN),the qualitative relationship between ECN and the catalytic activation of AB is clarified,and the optimal catalytic active site is ***,from the perspective of different reaction paths,we study the hydrolysis reaction of AB in multiple paths,and obtain 5 different reaction paths and energy *** calculation results show that in the case of N–H bond priority break (path 5),the reaction has the minimum rate-determining step (RDS) barrier (about 1.02 e V) and the entire reaction is exothermic (about 0.40 e V).So,path 5 is an optimal catalytic reaction *** study will have an important guiding significance for the study of the AB hydrolysis reaction mechanism.

关键词： The first-principles NH_(3)BH_(3) Hydrolysis reaction FeCo cluster Catalyst

Rich B active centers in Penta-B_(2)C as high-performance photocatalyst for nitrogen reduction

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Chinese Chemical Letters 2021年第12期32卷 3821-3824页

作者： Ran Wang Chaozheng He Weixing Chen chenxu zhao Jinrong Huo Institute of Environmental and Energy Catalysis School of Materials Science and Chemical EngineeringXi'an Technological UniversityXi'an 710021China Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices School of Materials Science and Chemical EngineeringXi'an Technological UniversityXi'an 710021China School of Sciences Xi'an Technological UniversityXi'an 710021China

The photocatalytic nitrogen reduction reaction(NRR) has mild reaction conditions and only requires sunlight energy as a driving force to replace the traditional ammonia synthesis method. We herein investigate the catalytic activity and selectivity on Penta-B_(2)C for NRR by using density functional theory calculations. Penta-B_(2)C is a semiconductor with an indirect bandgap(2.328 e V) and is kinetically stable based on molecular dynamic simulations. The optical absorption spectrum of Penta-B;C is achieved in the ultraviolet and visible range. Effective light absorption is more conducive to generate photo-excited electrons and improving photocatalytic performances. Rich B atoms as activation sites in Penta-B_(2)C facilitate capturing N_(2). The activated N_(2)molecule prefers the side-on adsorption configuration on Penta-B_(2)C, which facilitates the subsequent reduction reaction. Among considered NRR mechanisms on Penta-B_(2)C, the best pathway prefers the enzymatic mechanism, only required a low onset potential of 0.23 V. The hydrogen evolution reaction is inhibited when the hydrogen adsorption concentration is increased or N_(2)molecules first occupy the adsorption sites. Our results indicate Penta-B_(2)C is a highly reactive and selective photocatalyst for NRR. Our work provides theoretical insights into the experiments and has guiding significance to synthesize efficient NRR photocatalysts.

关键词： Nitrogen reduction Photocatalytic Penta-B_(2)C Mechanism B active center

Case study of performance assessment of overlapping shield tunnels with a small curve radius

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Deep Underground Science and Engineering 2024年第4期3卷 481-496页

作者： Xu Zhang Bin Luo Youjun Xu chenxu zhao Huachuan Wang School of Civil Engineering Inner Mongolia University of Science and TechnologyBaotouChina Engineering Research Center of Urban Underground Engineering at Universities of Inner Mongolia Autonomous Region BaotouChina Department of Civil and Environmental Engineering University of StrathclydeGlasgowUK

Due to the network planning of subways and their surrounding structures,increasingly more overlapping shields with a small curve radius have been constructed. A newly constructed upper tunnel partly overlaps a lower one, leading to the extremely complex uplift of the lower tunnel caused by the construction of a new tunnel. Based on the shield-driven project that runs from the Qinghe Xiaoyingqiao Station to the Qinghe Station in Beijing, which adopts the reinforcement measures of interlayer soil grouting and steel supports on site, in this study, the uplift pattern of the lower tunnel and the stress characteristics of steel supports were investigated through numerical simulations and on-site *** study results show that among all tunnel segments, the first segment of the shield witnesses a maximum uplift displacement that increases with the horizontal space between tunnels. On using either interlayer soil grouting or steel-ring bracing reinforcement, the uplift of the tunnel lining exceeds the control value;by contrast,when these two measures are jointly applied, the uplift of the tunnel lining does not exceed a maximum value of 4.87 mm, which can satisfy the requirements of deformation control. Under these two joint measures, the soil strength between two stacked shield tunnels can be enhanced and the uplift deformation can be restricted with the interlayer soil grouting. Also, the segmental deformation and overall stability of the existing tunnel can be controlled with the temporary steel *** deformation of circumferential supports and segments is closely related to each other, and the segmental uplift is controlled by H-shaped steel supports. With the increase in the horizontal space between twin shields, the effect of the construction would gradually weaken, accompanied by a gradual reduction of the stresses of steel supports. These findings provide a valuable reference for the engineering design and safe construction of overlapping shield tunn

关键词： field monitoring numerical simulation overlapping shields small curve radius steel support stress uplift of tunnel lining