检索结果-南通市图书馆

Double Moving Extremes Ranked Set Sampling Design

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第1期40卷 75-90页

作者： Meng chen Wang-xue chen Rui Yang Department of Mathematics and Statistics Jishou UniversityJishou416000China

The traditional simple random sampling(SRS)design method is inefficient in many *** proposed some new designs to increase *** this paper,as a variation of moving extremes ranked set sampling(MERSS),double MERSS(DMERSS)is proposed and its properties for estimating the population mean are *** turns out that,when the underlying distribution is symmetric,DMERSS gives unbiased estimators of the population ***,it is found that DMERSS is more efficient than the SRS and MERSS methods for usual symmetric distributions(normal and uniform).For asymmetric distributions considered in this study,the DMERSS has a small bias and it is more efficient than SRS for usual asymmetric distribution(exponential)for small sample sizes.

关键词： double moving extremes ranked set sampling symmetric distribution efficiency

Emerging perovskite materials for supercapacitors:Structure,synthesis,modification,advanced characterization,theoretical calculation and electrochemical performance

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第2期89卷 41-70,I0003页

作者： Yuehua Qian Qingqing Ruan Mengda xue Lingyun chen Department of Applied Chemistry School of Chemistry and Chemical EngineeringChongqing UniversityChongqing 401331China

As a new generation electrode materials for energy storage,perovskites have attracted wide attention because of their unique crystal structure,reversible active sites,rich oxygen vacancies,and good *** this review,the design and engineering progress of perovskite materials for supercapacitors(SCs)in recent years is ***,the review will focus on four types of perovskites,perovskite oxides,halide perovskites,fluoride perovskites,and multi-perovskites,within the context of their intrinsic structure and corresponding electrochemical performance.A series of experimental variables,such as synthesis,crystal structure,and electrochemical reaction mechanism,will be carefully analyzed by combining various advanced characterization techniques and theoretical *** applications of these materials as electrodes are then featured for various ***,we look forward to the prospects and challenges of perovskite-type SCs electrodes,as well as the future research direction.

关键词： Perovskite Modification engineering Oxygen vacancy Theoretical calculation methodology Supercapacitor

Estimation of surface geometry on combustion characteristics of AP/HTPB propellant under rapid depressurization

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3期33卷 546-558页

作者： Kaixuan chen Zhenwei Ye Xiaochun xue Yonggang Yu School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina School of Science Hangzhou Dianzi UniversityHangzhou 310018ZhejiangChina

The 2D sandwich model serves as a potent tool in exploring the influence of surface geometry on the combustion attributes of Ammonium perchlorate/Hydroxyl-terminated polybutadiene(AP/HTPB)propellant under rapid pressure *** thickness of the sandwich propellant is derived from slicing the 3. random particle packing,an approach that enables a more effective examination of the micro-flame *** analysis of the predicted burning characteristics has been performed with experimental *** findings demonstrate a reasonable agreement,thereby validating the precision and soundness of the *** on the typical rapid depressurization environment of solid rocket motor(initial combustion pressure is 3.MPa and the maximum depressurization rate is 1000 MPa/s).A-type(a flatter surface),B-type(AP recesses from the combustion surface),and C-type(AP protrudes from the combustion surface)propellant combustion processes are numerically *** comparison of the evolution of gas-phase flame between 0.1 and 1 ms,it is discerned that the flame strength and form created by the three sandwich models differ significantly at the beginning stage of depressurization,with the flame structures gradually becoming harmonized over *** are drawn by comparison extinction times:the surface geometry plays a pivotal role in the combustion process,with AP protrusion favoring combustion the most.

关键词： AP/HTPB propellant BDP model Rapid pressure decay Burning surface geometry

A review on plasmonic enhancement of activity and selectivity in electrocatalytic CO_(2)reduction

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2024年第4期18卷 399-417页

作者： Jing xue Zhenlin chen Yuchao ZHANG Jincai ZHAO Key Laboratory of Photochemistry Beijing National Laboratory for Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Utilizing plasmonic effects to assist electrochemical reactions exhibits a huge potential in tuning the reaction activities and product selectivity,which is most appealing especially in chemical reactions with multiple products,such as CO_(2)reduction reaction(CO_(2)RR).However,a comprehensive review of the development and the underlying mechanisms in plasmon-assisted electrocatalytic CO_(2)RR remains few and far ***,the fundamentals of localized surface plasmonic resonance(LSPR)excitation and the properties of typical plasmonic metals(including Au,Ag,and Cu)are ***,the potential mechanisms of plasmonic effects(such as hot carrier effects and photothermal effects)on the reaction performance in the field of plasmon-assisted electrocatalytic CO_(2)RR are summarized,which provides directions for the future development of this *** is concluded that plasmonic catalysts exhibit potential capabilities in enhancing CO_(2)RR while more in situ techniques are essential to further clarify the inner mechanisms.

关键词： localized surface plasmonic resonance(LSPR)effect plasmonic metals CO_(2)reduction reaction(CO_(2)RR) hot carrier effect photothermal effect

Coupled DEM-FDM analyses of the effects of falling rock’s shape and impact angle on response of granular cushion and rock shed

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 Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3353-3364页

作者： Jingyu xue chen Cao Jianhua Yan Yaopeng Ji Jianping chen College of Construction Engineering Jilin UniversityChangchun130026China School of Earth Sciences and Engineering Hohai UniversityNanjing210098China

Rock shed is an effective protection measure against *** investigate the influences of falling rock’s shape and impact angle on the impact effect of the cushioned rock shed,a modeling approach for a rock shed with a cushion layer using *** granular cushion is modeled as an aggregate of discrete non-cohesion particles,while the concrete plate and the beam are modeled as *** falling rock with different sphericities and impact angles is modeled as a rigid *** numerical model is validated by comparing the simulation results with experimental and numerical results from previous *** model is applied to analyze the effects of rock shape and impact angle on the dynamic interaction effects between falling rock and cushioned rock shed,including the impact force,transmitted bottom force,penetration depth,and plate *** numerical results show that the variation in the falling rock’s shape has different effects on the falling rock with different impact *** findings could support rock shed design by revealing the limitations of the assumptions in the past research,which may result in unsafe rock sheds for some rockfall cases.

关键词： Rockfall Coupled DEM-FDM analysis Rock’s shape Impact angle Granular cushion Rock shed

Path Planning for AUVs Based on Improved APF-AC Algorithm

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第3期78卷 3721-3741页

作者： Guojun chen Danguo cheng Wei chen {3. Yang Tiezheng Guo Industrial Center Nanjing Institute of TechnologyNanjing211167China

With the increase in ocean exploration activities and underwater development,the autonomous underwater vehicle(AUV)has been widely used as a type of underwater automation equipment in the detection of underwater ***,nowadays AUVs generally have drawbacks such as weak endurance,low intelligence,and poor detection *** research and implementation of path-planning methods are the premise of AUVs to achieve actual *** improve the underwater operation ability of the AUV,this paper studies the typical problems of path-planning for the ant colony algorithm and the artificial potential field *** response to the limitations of a single algorithm,an optimization scheme is proposed to improve the artificial potential field ant colony(APF-AC)*** with traditional ant colony and comparative algorithms,the APF-AC reduced the path length by 1.57%and 0.63.(in the simple environment),8.92%and 3.46%(in the complex environment).The iteration time has been reduced by approximately 28.48%and 18.05%(in the simple environment),18.53.and 9.24%(in the complex environment).Finally,the improved APF-AC algorithm has been validated on the AUV platform,and the experiment is consistent with the *** APF-AC algorithm can effectively reduce the underwater operation time and overall power consumption of the AUV,and shows a higher safety.

关键词： Path-planning autonomous underwater vehicle ant colony algorithm artificial potential field bio-inspired neural network

LaMnO_(3./Co_(3.O_(4) nanocomposite for enhanced triethylamine sensing properties

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 Rare Earths 2024年第4期42卷 733-742页

作者： Jian Zhang Yanping chen Ling Li xue chen Wenya An Xiujuan Qian Yuye Tao School of Science Shandong Jianzhu UniversityJinan250100China

LaMnO_(3. modified Co_(3.O_(4) nanocomposites were prepared by simple hydrothermal method co mbined with sol-gel *** gas sensitivity properties of pure Co_(3.O_(4) and LaMnO_(3./Co_(3.O_(4) with different composite proportions are *** is found that 0.6-LMO/Co_(3.O_(4) sensor has higher sensitivity to triethylamine(TEA)than pure Co_(3.O_(4) sensor,which is improved by 9.27 *** the working temperature is reduced from 150 to 13.℃.Besides,it has excellent gas selectivity and *** improvement of the gas sensitivity of LaMnO_(3./Co_(3.O_(4) sensor may be due to the fact that LaMnO_(3. is an effective catalyst,and the catalytic performance perhaps is beneficial to improving the sensing *** addition,the formation of p-p heterojunctions may be the key factor to improve the gas sensing *** work provides a new Co_(3.O_(4)-based gas sensing material for the detection of TEA.

关键词： Gas sensing Co_(3.O_(4) LaMnO_(3. Triethylamine Rareearths

Effect of ceramic work rolls on surface roughness of rolled SUS3.4 ultra-thin strips

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第7期31卷 1704-1718页

作者： Peng-cheng Li Tao Wang chen-chen Zhao Qi Liu Qing-{3. Huang College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024ShanxiChina Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment of Ministry of Education Taiyuan University of TechnologyTaiyuan 030024ShanxiChina National Key Laboratory of Metal Forming Technology and Heavy Equipment Taiyuan University of TechnologyTaiyuan 030024ShanxiChina

Surface morphology and roughness are important parameters of surface quality of cold-rolled ultra-thin strip *** order to study the effect of Si_(3.N_(4) ceramic work rolls on the surface roughness of SUS3.4 ultra-thin strip,ABAQUS finite element model calculation,3. laser profilometry,and other methods were adopted based on the physical characteristics of Si_(3.N_(4) ceramic roll and 9Cr2MoV steel roll,like anti-flattening performance and oil *** surface morphology and roughness of SUS3.4 ultra-thin strip rolled by different material work rolls under oil lubrication conditions were *** results showed that under the rolling force of 10 kN,the maximum flattening amount of Si_(3.N_(4) ceramic roll was reduced by 3..14%compared to that of 9Cr2MoV steel *** reduction rate of SUS3.4 ultra-thin strip rolled by ceramic roll was 3..19%,while that rolled by steel roll was only 22%;Si_(3.N_(4) ceramic roll can further increase the number of alternating convex peaks and concave valleys in the rolled thin strip,reduce the profile steepness,reduce surface roughness,and enhance the planarization effect of surface micro-convex bodies,with improving surface quality and surface ***,the mechanism of Si_(3.N_(4) ceramic roll significantly improving the surface roughness of rolled SUS3.4 ultra-thin strip was proposed.

关键词： Ceramic work roll-Steel roll SUS3.4 ultra-thin strip Reduction Surface roughness

Curved anisotropic polaritons

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第3期19卷 217-224页

作者： Tao Hou Yixiao Ge Shuwen xue Huanyang chen Department of Physics and Institute of Electromagnetics and Acoustics Xiamen UniversityXiamen 361005China Jiujiang Research Institute of Xiamen University Jiujiang 332000China

The curved surface has emerged as new research platform for understanding and manipulating novel electromagnetic behaviors in complex media. In this paper, we explore the anisotropic polaritons on the spherical surface based on Maxwell’s fish-eye metric through stereographic projection. Additionally, this phenomenon can be extended to spindle surface by conformal mapping. Our calculations and simulations demonstrate the elliptic and hyperbolic polaritons, excited by an electric dipole on the sphere, will self-focus or focus on the poles on the sphere affected by anisotropic permittivity. Furthermore, we reveal the optical singularity nature of the curved hyperbolic polaritons from the perspective of transformation optics by obtaining the equivalent optical refractive index profiles and the particle potential energy. Based on natural anisotropic materials and metamaterials, the curved polaritons have potential applications in curved surface focusing and chaos regulation. This work not only bridges the transformation optics and anisotropic polaritons at curved surface, but also provides a new route to surface optical field manipulation.

关键词： anisotropic polaritons transformation optics curved surface