检索结果-南通市图书馆

Elliptically polarized high-order harmonic generation of Ar atom in an intense laser field

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第5期33卷 453-457页

作者：胡杰王一琛景秋霜姜威王革文赵逸文肖礴梁红静马日 institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China College of Science Jilin Institute of Chemical TechnologyJilin 132022China

High-order harmonic generation(HHG) of Ar atom in an elliptically polarized intense laser field is experimentally investigated in this ***,the anomalous ellipticity dependence on the laser ellipticity(ε) in the lower-order harmonics is observed,specifically in the 13rd-order,which displays a maximal harmonic intensity at ε ≈ 0.1,rather than at ε = 0 as *** contradicts the general trend of harmonic yield,which typically decreases with the increase of laser *** this study,we attribute this phenomenon to the disruption of the symmetry of the wave function by the Coulomb effect,leading to the generation of a harmonic with high *** finding provides valuable insights into the behavior of elliptically polarized harmonics and opens up a potential way for exploring new applications in ultrafast spectroscopy and light–matter interactions.

关键词： high-order harmonic generation Coulomb effect elliptically polarized intense laser field

Observer-based robust high-order fully actuated attitude autopilot design for spinning glide-guided projectiles

在线全文

学校读者我要写书评

暂无评论

Defence technology（防务技术） 2024年第4期34卷 282-294页

作者： Wei Wang Yuchen Wang Shiwei Chen Yongcang Guo Zhongjiao Shi School of aerospace Engineering Beijing Institute of TechnologyBeijing 10081China Northwest Industries Group CO. Ltd.Xi'an 710043China

This paper investigates the design of an attitude autopilot for a dual-channel controlled spinning glideguided projectile(SGGP),addressing model uncertainties and external *** on fixed-time stable theory,a disturbance observer with integral sliding mode and adaptive techniques is proposed to mitigate total disturbance effects,irrespective of initial *** introducing an error integral signal,the dynamics of the SGGP are transformed into two separate second-order fully actuated ***,employing the high-order fully actuated approach and a parametric approach,the nonlinear dynamics of the SGGP are recast into a constant linear closed-loop system,ensuring that the projectile's attitude asymptotically tracks the given goal with the desired *** the proposed composite control framework,the ultimately uniformly bounded stability of the closed-loop system is rigorously demonstrated via the Lyapunov *** of the effectiveness of the proposed attitude autopilot design is provided through extensive numerical simulations.

关键词： Spinning glide-guided projectile Attitude control Sliding mode disturbance observer Fixed-time stable theory High-order fully actuated approach

Cable-driven legged landing gear for unmanned helicopter:Prototype design,optimization and performance assessment

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第4期67卷 1196-1214页

作者： TIAN BaoLin GAO HaiBo YU HaiTao SHAN HaoMin HOU JunChen YU HongYing DENG ZongQuan State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China China Academy of aerospace Science and Innovation Beijing 100048China

Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging *** study presents a novel cable-driven legged landing gear(CLG)with differential transmission for unmanned helicopters in complex landing *** obtain the preferred configuration of the legged mechanism,a multi-objective optimization framework for the CLG is constructed by concurrently considering terrain adaptability,landing stability and reasonable linkage of internal *** non-dominated sorting genetic algorithmⅡis employed to numerically acquire the optimal scale parameters that guide the mechanical design of the *** unmanned helicopter prototype equipped with the devised CLG is developed with key performance *** results show that the devised CLG can provide energy-efficient support over uneven terrains(totally driven torque demand less than 0.1 N m)in quasi-static landing tests,and favorable terrain adaptability(posture fluctuation of the fuselage less than±1°)in unknown slope landing *** exhibited merits give the proposed CLG the potential to enhance the landing performance of future aircraft in extreme environments.

关键词： unmanned helicopter adaptive landing gear experimental verification

The effect of Ti and Zr content on the structure,mechanics and energy-release characteristics of Ti—Zr—Ta alloys

在线全文

学校读者我要写书评

暂无评论

Defence technology（防务技术） 2024年第1期31卷 343-350页

作者： Jia-yu Meng Jing-zhi He Bin Zhang Jin Chen Shun Li Dun Niu Yu Tang Xi’an Modern Chemistry Research institute Xi'an710065China College of aerospace Science and Engineering National University of Defense TechnologyChangsha410073China

Energetic structural materials(ESMs)are a new type of structural materials with bearing and damage *** this work the microstructure,mechanical properties and energy release characteristics of multi-element Ti-Zr-Ta alloys with good casting performance were *** microstructure of the Ti_(x)ZrTa alloys gradually change from BCC+HCP to single BCC structure with the increase of *** the Ti_(2)Zr_(y)Ta alloys was still uniform and single BCC structure with the increase of *** evolution of microstructure and composition then greatly affect the mechanical properties and energy-release characteristics of Ti-Zr-Ta *** synergistic effect of dual phase structure increases the fracture strain of Ti_(x)ZrTa(x=0.2,0.5)with the Ti content decreases,while the fracture strain of Ti_(x)ZrTa(x=2.0,3.0,4.0)gradually increase with the Ti content increases caused by the annihilation of the obstacles for dislocation *** as Zr content increases,the fracture strain of Ti_(2)Zr_(y)Ta alloys decrease,then the oxidation reaction rate and fragmentation degree gradually *** higher oxidation rate and the lager exposed oxidation area jointly leads the higher releasing energy efficiency of Ti_(x)ZrTa alloys with low Ti content and Ti_(2)Zr_(y)Ta alloys with high Zr content.

关键词： Energetic structural materials Ti-Zr-Ta Multi-element alloy Energy release characteristics

Facet effects on bimetallic ZnSn hydroxide microcrystals for selective electrochemical CO2 reduction

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第8期9卷 1314-1320页

作者： Liu Han Cheng-wei Wang Shan-shan Luo Ying-tang Zhou Bing Li Ming Liu School of Chemistry and chemical Engineering Harbin Institute of Technology National Engineering Research Center for Marine Aquaculture Marine Science and Technology CollegeZhejiang Ocean University

Employing crystal facets to regulate the catalytic properties in electrocatalytic carbon dioxide reduction reaction（eCO2RR） has been well demonstrated on electrocatalysts containing single metals but rarely explored for bimetallic systems. Here, we synthesize Zn Sn（OH）6（ZSO）microcrystals（MCs） with distinct facets and investigate the facet effects in eCO2RR. Electrochemical studies and in situ Fourier Transform Infrared Spectroscopy（in situ-FTIR） reveal that ZSO MCs produce mainly C1 products of HCOOH and CO. The {111} facet of the ZSO MCS exhibits higher selectivity and faradaic efficiency（FE） than that of the {100} facet over a wide range of potentials（-0.9 V ～-1.3 V versus RHE）. Density Functional Theory（DFT） calculations elucidate that the {111} facet is favorable to the adsorption/activation of CO2molecules,the formation of intermediate in the rate-determining step, and the desorption of C1 products of CO and HCOOH molecules.

关键词： ZnSn(OH) 6 Crystal facets Electrochemical carbon dioxide reduction C1 product Density functional theory

Enhanced electrocatalytic CO_(2)reduction to formic acid using nanocomposites of In_(2)O_(3)@C with graphene

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 5031-5039页

作者： Wenxiang Li Shuo Gao Chuanruo Yang Juntao Yang Amjad Nisar Guolei Xiang Junsu Jin Beijing Key Laboratory of Membrane Science and technology Beijing University of Chemical TechnologyBeijing 100029China Nanomaterials Research Group PDPINSTECHIslamabad 44000Pakistan institute of Industrial Chemistry College of ChemistryBeijing University of Chemical TechnologyBeijing 100029China

In_(2)O_(3)is an effective electrocatalyst to convert CO_(2)to formic acid(HCOOH),but its inherent poor electrical conductivity limits the efficient charge transfer during the ***,the tendency of In_(2)O_(3)particles to agglomerate during synthesis further limits the exposure of active *** we address these issues by leveraging the template effect of graphene oxide and employing InBDC as a self-sacrificing template for the pyrolysis synthesis of In_(2)O_(3)@*** resulting In_(2)O_(3)@C/rGO-600 material features In_(2)O_(3)@C nanocubes uniformly anchored on a support of reduced graphene oxide(rGO),significantly enhancing the active sites *** conductive rGO network facilitates charge transfer during electrocatalysis,and the presence of oxygen vacancies generated during pyrolysis,combined with the strong electron-donating ability of rGO,enhances the adsorption and activation of CO_(2).In performance evaluation,In_(2)O_(3)@C/rGO-600 exhibits a remarkable HCOOH Faradaic efficiency exceeding 94.0%over a broad potential window of−0.7 to−1.0 V(*** hydrogen electrode(RHE)),with the highest value of 97.9%at−0.9 V(***)in a ***,the material demonstrates an excellent cathodic energy efficiency of 71.6%at−0.7 V(***).The study underscores the efficacy of uniformly anchoring metal oxide nanoparticles onto rGO for enhancing the electrocatalytic CO_(2)reduction performance of materials.

关键词： In_(2)O_(3)@C nanocomposite electrochemical CO_(2)reduction reduced graphene oxide oxygen vacancy

[H_(2)dab][GaB_(5)O_(10)]:an Acentric Galloborate with a 4-Connected Uninodal Framework

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

chemical Research in Chinese Universities 2024年第4期40卷 747-752页

作者： LIU Wenfang CHEN Chongan YANG Guoyu School of Chemistry and chemical Engineering Beijing Institute of TechnologyBeijing102488P.R.China

A new acentric galloborate(GBO)[H_(2)dab][GaB_(5)O_(10)](1,1,4-dab:1,4-diaminobutane)has been synthesized under solvothermal *** alternation of 4,4-connected GaO4 and B5O10 cluster build up the 3D[GaB_(5)O_(10)]_(n)^(2n-)uninodal framework,which contains three pairs of helical channels with 8-member ring(MR)and 7-MR apertures,*** 1 exhibits a moderate second harmonic generation(SHG)response of 1.8 times that of KH_(2)PO_(4)(KDP),indicating its potential application in UV *** acentric uninodal framework in compound 1 represents a new type of zeolitic framework in the GBOs’family.

关键词： Galloborate Solvothermal synthesis Nonlinear optics Zeolitic framework

Effect of expansion waves on cowl shock wave and boundary layer interaction in hypersonic inlet

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Propulsion and Power Research 2024年第1期13卷 80-97页

作者： Guangwei Wu Ziao Wang Teng Shi Zhibin Zhang Weiyu Jiang Fuxu Quan Juntao Chang Harbin institute of technology Harbin 150001China Xi’an aerospace Propulsion institute Xi’an 710100China Beijing Power Machinery institute Beijing 100074China

The interaction of cowl shock wave and boundary layer has a crucial effect on the stability,operability and performance of hypersonic *** studies on inhibiting the sep-aration and managing the strength of the interaction of the shock wave and boundary layer with expansion corner have been ***,the expansion waves near the circular arc shoulder to effectively control the interaction and cowl shock arrangement is little ***,the interaction of the cowl shock wave and boundary layer under thefluence of the expansion waves is studied by inviscid and viscous numerical *** results reveal that the expansion waves have an important impact on the interaction between the cowl shock wave and boundary layer and the strength of shock wave,and that there are four types of inter-action processes with the change of the relative impingement positions of cowl shock *** expansion waves have a different influence on the shock wave and boundary layer inter-action at different incident *** the incident point of the cowl shock wave goes far downstream from the end of the circular arc shoulder,the influence of expansion waves is weakened,and the magnitude of separation zone ***,when the expansion waves are applied to the interaction of the cowl shock wave and boundary layer on the circular arc shoulder,the separation can be effectively *** particular,while the expansion waves interact with the shock wave and boundary layer in the back half of the circular arc shoulder,the separation is best *** with the upstream and downstream inci-dent points,the scale of separation area in the optimal control region is reduced by 65.3%at ***,the total pressure recovery coefﬁcientﬁrst increases and then decreases when the cowl moves from upstream to downstream,and the total pressure recovery coefﬁcient reaches the maximum value of 68.36%at the incident position of cowl shock wave d Z 8.09d0.

关键词： Boundary layer Expansion waves Cowl shock wave Separation Hypersonic inlet Circular arc shoulder Inviscid and viscous numerical simulations

Constructing high-toughness polyimide binder with robust polarity and ion-conductive mechanisms ensuring long-term operational stability of silicon-based anodes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第6期93卷 580-591,I0014页

作者： Yongjun Kang Nanxi Dong Fangzhou Liu Daolei Lin Bingxue Liu Guofeng Tian Shengli Qi Dezhen Wu State Key Laboratory of chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China ENFI R&D institute China ENFI Engineering CorporationBeijing 100038China China Automotive Battery Research institute Co. Ltd.Beijing 101407China Changzhou institute of Advanced Materials Beijing University of Chemical TechnologyChangzhou 213164JiangsuChina

Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical ***,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion ***,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high *** plentiful polar carboxyl(-COOH) groups establish robust bonding *** ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles ***,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 *** perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.

关键词： Polyimide binder High toughness Robust ionic transport Silicon-based anodes Lithium-ion batteries