检索结果-南通市图书馆

TWO-STEP SCHEME FOR BACKWARD STOCHASTIC DIFFERENTIAL EQUATIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2023年第2期41卷 287-304页

作者： qiang Han Shaolin ji Zhongtai Securities Institute for Financial Studies Shandong UniversityJinan 250100China

In this paper,a stochastic linear two-step scheme has been presented to approximate backward stochastic differential equations(BSDEs).A necessary and sufficient condition is given to judge the L 2-stability of our numerical *** stochastic linear two-step method possesses a family of 3-order convergence schemes in the sense of strong *** coefficients in the numerical methods are inferred based on the constraints of strong stability and n-order accuracy(n∈N^(+)).Numerical experiments illustrate that the scheme is an efficient probabilistic numerical method.

关键词： Backward stochastic differential equation Stochastic linear two-step scheme Local truncation error Stability and convergence

Electrocatalytic nitrite reduction to ammonia on isolated bismuth alloyed ruthenium

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 2025年第1期 369-376页

作者： Shiyao Shang Fuzhou wang Zeyi Sun Chaofan qiang Ke Chu School of Materials Science and Engineering Lanzhou Jiaotong University

Electrochemical reduction of NO2-to NH3（NO2-RR） is recognized as an appealing approach for achieving renewable NH3synthesis and waste ***,we report isolated Bi alloyed Ru （Bi1Ru） as an efficient NO2-RR *** calculations and in situ electrochemical measurements reveal the creation of Bi1-Ru dual sites which can remarkably promote NO2-activation and suppress proton adsorption,while accelerating the NO2-RR protonation energetics to render a high NO2--to-NH3conversion ***,Bi1Ru assembled in a flow cell delivers an NH3yield rate of 1901.4μmol h-1cm-2and an NH3-Faradaic efficiency of 94.3%at an industrial-level current density of 324.3 mA *** study offers new perspectives for designing and constructing p-block single-atom alloys as robust and high-current-density NO2-RR catalysts toward the ammonia electrosynthesis.

关键词：

Numerical Analysis of PRISM-PY Calculations for Hard-and Soft-Core Generic Polymer Models

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 Journal of Polymer Science 2024年第4期42卷 532-543页

作者： qiang wang Department of Chemical and Biological Engineering Colorado State University1370 Campus DeliveryFort CollinsCO80523-1370USA

Generic polymer models capturing the chain connectivity and excluded-volume interactions between polymer segments can be classified, according to whether or not the 3D integral of the latter diverges, into hard- and soft-core models. Taking homogeneous systems of compressible homopolymer melts (or equivalently homopolymer solutions in an implicit, good solvent) in the continuum as an example, we recently compared the correlation effects on the structural and thermodynamic properties of the hard- and soft-core models given by the polymer reference interaction site model (PRISM) theory with the Percus-Yevick (PY) closure (Polymers 2023, 15, 1180). Here we analyzed in detail the numerical errors and behavior of the interchain pair correlation functions (PCFs) given by the PRISM-PY calculations of these models using an efficient numerical approach that we proposed. Our numerical approach has the least number of independent variables to be iteratively solved, analytically treats the discontinuities caused by the non-bonded pair potential (such as that of the hard spheres) and takes only the inverse Fourier transform of the interchain indirect PCF between polymer segments (which is continuous and decays towards 0 with increasing wavenumber much faster than both the interchain direct and total PCFs), and is essential for us to accurately solve the PRISM-PY theory for chain length N as large as 106. To capture the correlation-hole effect, the real-space cut-off in the PRISM calculations should be proportional to the square root of N.

关键词： Generic polymer models Soft potentials Polymer reference interaction site model theory

Learning with privileged information using Bayesian networks

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2015年第2期9卷 185-199页

作者： Shangfei wang Menghua HE Yachen ZHU Shan HE Yue LIU qiang ji School of Computer Science and Technology University of Science and Technology of China Hefei 230027 China Key Lab of Computing and Communicating Software of Anhui Province Hefei 230027 China School of Mathematical Sciences University of Science and Technology of China Hefei 230027 China Department of Electrical Computer and Systems Engineering Rensselaer Polytechnic Institute Troy NY 12180-3590 USA

For many supervised learning applications, addi- tional information, besides the labels, is often available dur- ing training, but not available during testing. Such additional information, referred to the privileged information, can be exploited during training to construct a better classifier. In this paper, we propose a Bayesian network （BN） approach for learning with privileged information. We propose to in- corporate the privileged information through a three-node BN. We further mathematically evaluate different topologies of the three-node BN and identify those structures, through which the privileged information can benefit the classifica- tion. Experimental results on handwritten digit recognition, spontaneous versus posed expression recognition, and gender recognition demonstrate the effectiveness of our approach.

关键词： Bayesian network privileged information clas-sification maximum likelihood estimation

Influence of Reynolds Number on the Unsteady Aerodynamics of Integrated Aggressive Intermediate Turbine Duct

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2018年第3期27卷 294-303页

作者： LIU Hongrui LIU Jun ji Lucheng DU qiang LIU Guang wang Pei School of Aerospace Engineering Beijing Institute of Technology Beijing 100081 China Key Laboratory of Light-Duty Gas-Turbine Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China

The ultra-high bypass ratio turbofan engine attracts more and more attention in modern commercial engine due to advantages of high efficiency and low Specific Fuel Consumption(SFC). One of the characteristics of ultra-high bypass ratio turbofan is the intermediate turbine duct which guides the flow leaving high pressure turbine(HPT) to low pressure turbine(LPT) at a larger diameter, and this kind of design will lead to aggressive intermediate turbine duct(AITD) design concept. Thus, it is important to design the AITD without any severe loss. From the unsteady flow's point of view, in actual operating conditions, the incoming wake generated by HPT is unsteady which will take influence on boundary layer's transition within the ITD and LPT. In this paper, the three-dimensional unsteady aerodynamics of an AITD taken from a real engine is studied. The results of fully unsteady three-dimensional numerical simulations, performed with ANSYS-CFX(RANS simulation with transitional model), are critically evaluated against experimental data. After validation of the numerical model, the physical mechanisms inside the flow channel are analyzed, with an aim to quantify the sensitivities of different Reynolds number effect on both the ITD and LPT nozzle. Some general physical mechanisms can be recognized in the unsteady environment. It is recognized that wake characteristics plays a crucial role on the loss within both the ITD and LPT nozzle section, determining both time-averaged and time-resolved characteristics of the flow field. Meanwhile, particular attention needs to be paid to the unsteady effect on the boundary layer of LPT nozzle's suction side surface.

关键词： Intermediate Turbine Duct Unsteady Simulation Reynolds Number Flow Field Analysis

Influences of preparation techniques on glass-forming ability of Fe-P-B-Si-C amorphous alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2018年第6期25卷 674-679页

作者： ji-jun Zhang Ya-qiang Dong Lu-yang Bie qiang Li jia-wei Li Xin-min wang Key Laboratory of Magnetic Materials and Devices NingboInstitute of Materials Technology and Engineering ChineseAcademy of Sciences Ningbo 315201 Zhejiang China Zhejiang Province Key Laboratory of Magnetic Materials andApplication Technology Ningbo Institute of MaterialsTechnology and Engineering Chinese Academy of SciencesNingbo 315201 Zhejiang China University of Chinese Academy of Sciences Beijing 100049China School of Physics Science and Technology XinjiangUniversity Urumqi 830046 Xinjiang China

It has been widely accepted that the ultrafast cooling rate is required for the glass formation of amorphous alloys. Here, the larger glass-forming ability （GFA） of Fe76P5（B0.5Si0.3C0.2）19 amorphous alloy was achieved by water quenching at lower cooling rate under argon atmosphere. Cylindrical rods with diameters of 1-2 mm were prepared by water quenching without flux treatment, Cu-mold injection casting, and Cu-mold suction casting, respectively. The influences of the preparation techniques with different cooling rates on GFA, thermal property, and nucleation/growth behavior were examined. The critical diameter of the Fe76P5（B0.5Si0.3C0.2）19 amorphous alloys is 1.7 mm for water quenching while smaller than 1.0 mm for injection casting. Microstructure analysis indicates that the crystallization and solidification processes are quite different between the water-quenched and the injection-cast rods. These findings could deepen fun-damental understanding on the relationship between the cooling rate, techniques, and GFA of Fe-based amorphous alloys.

关键词： Fe-based amorphous alloy Preparation technique Glass-forming ability Crystallization behavior

jinfengopteryx Compared to Archaeopteryx,with Comments on the Mosaic Evolution of Long-tailed Avialan Birds

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

Acta Geologica Sinica(English Edition) 2007年第3期81卷 337-343页

作者： ji Shu＇an ji qiang Institute of Geology Chinese Academy of Geological Sciences Beijing 100037

jinfengopteryx is a newly uncovered Archaeopteryx-like avialan bird outside Germany, which was found from the Jehol Biota of northern Hebei in northeastern China. It shares many characters only with Archaeopteryx by the possession of three fenestrae in the antorbital cavity, 23 caudal vertebrae and long tail feathers attached to all the caudal vertebrae. But the former differs from the latter in the relatively short and high preorbital region of skull, more and closely packed teeth, much shorter forelimb compared to hindlimb. Such differences indicate jinfengopteryx is even slightly more primitive than Archaeopteryx, although both birds can be placed at the root position of the avialan tree based on cladistic analysis. Shenzhouraptor is suggested to be slightly more advanced than jinfengopteryx ＋ Archaeopteryx, supported by some derived features in teeth, shoulder girdles and forelimbs such as the reduction of tooth number, dorsolaterally directed glenoid facet, very long forelimb and comparatively short manus. Meanwhile, the tail of Shenzhouraptor shows more primitive characters than those of jinfengopteryx and Archaeopteryx, e.g., the strikingly longer tail composed of more caudal vertebrae and the long tail feathers attached only to distal caudal segments. The mixed primitive and advanced characters reveal the evident mosaic evolution among long-tailed avialan birds.

关键词： jinfengopteryx Archaeopteryx long-tailed avialans mosaic evolution Mesozoic

Spaso与Hippocrates复位法治疗急性肩关节前脱位的比较研究

在线全文

学校读者我要写书评

暂无评论

中国骨与关节损伤杂志 2016年第9期31卷 940-943页

作者：纪泉王强石磊孙凤坡刘光年文良元北京医院骨科国家老年医学中心北京100730

目的比较Spaso复位法与Hippocrates复位法治疗急性肩关节前脱位的疗效。方法回顾性分析自2009-01—2014-06诊治的急性肩关节前脱位,自2009-01—2011-06采用Hippocrates法复位26例（Hippocrates组）,自2011-07—2014-06采用Spaso法复位37例（Spaso组）,关节腔注射利多卡因后手法复位。比较2组复位成功率、并发症、复位用时、VAS评分及肩关节功能Constant评分。结果 Hippocrates组获得平均4.5（3~6）个月随访。Spaso组获得平均4.7（3~8）个月随访。与Hippocrates组相比,Spaso组复位用时更少（t=2.143,P=0.037）,复位成功率更高（χ^2=3.934,P=0.047）,差异有统计学意义（P〈0.05）。2组复位后VAS评分（t=0.881,P=0.383）、并发症发生率（χ^2=1.922,P=0.166）、末次随访时肩关节功能Constant评分（t=1.689,P=0.098）比较差异无统计学意义（P〉0.05）。结论 Spaso复位法治疗急性肩关节前脱位比Hippocrates复位法的成功率更高,操作简单易行,但应注意急性肩关节前脱位合并损伤的诊治。

关键词：急性肩关节前脱位手法复位 Spaso复位法 Hippocrates复位法并发症

Xinghaiornis lini (Aves: Ornithothoraces) from the Early Cretaceous of Liaoning: An Example of Evolutionary Mosaic in Early Birds

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2013年第3期87卷 686-689页

作者： wang Xuri Chiappe M. LUIS TENG Fangfang ji qiang Institute of Geology Chinese Academy of Geological Sciences The Dinosaur Institute Natural History Museum of Los Angeles County Xinghai Paleontological Museum of Dalian

We describe a new species of Early Cretaceous bird from the Yixian Formation of Liaoning Province. Xinghaiornis lini gen. et sp. nov. is relatively large and characterized by a long, toothless rostrum and an elevated pedal digit I. The design of the skull and feet suggests that this bird was likely a mud-prober. This discovery provides strong support indicating that this avian trophic specialization originated at least 125 million years ago.

关键词： Early Cretaceous Xinghaiornis lini Yixian Formation avian trophic specialization