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A Power Penalty Approach to Numerical Solutions of Two-Asset American Options

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Numerical Mathematics(Theory,Methods and Applications) 2009年第2期2卷 202-223页

作者： k. zhang S. Wang X. Q. Yang k. L. Teo Department of Finance Business School Shenzhen University Shenzhen China School of Mathematics and Statistics University of Western Australia Australia Department of Applied Mathematics The Hong Kong Polytechnic University Hong Kong Department of Mathematics and Statistics Curtin University of Technology Australia

This paper aims to develop a power penalty method for a linear parabolic variational inequality （VI） in two spatial dimensions governing the two-asset American option valuation. This method yields a two-dimensional nonlinear parabolic PDE containing a power penalty term with penalty constant λ〉 1 and a power parameter k.〉 0. We show that the nonlinear PDE is uniquely solvable and the solution of the PDE converges to that of the VI at the rate of order O（λ^-k.2）. A fitted finite volume method is designed to solve the nonlinear PDE, and some numerical experiments are performed to illustrate the usefulness of this method.

关键词： Complementarity problem option pricing penalty method finite volume method.

High-temperature Oxidation Resistant Coatings Composed of YSZ Particles Pack.ged by Nano-Al_2O_3 Film

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中国腐蚀与防护学报 2009年第4期29卷 316-317页

作者： Y. D. HE C. REN k. zhang Beijing k.y Laboratory for Corrosion Erosion and Surface Technology University of Science and Technology Beijing 100083 Beijing China

The alloy performance to resist high-temperature oxidation is mainly determined either by the formation of oxide scales or by the deposition of oxide coatings on the surface of *** the former case,a protective oxide scale,such as Al_2O_3,Cr_2O_3 and SiO_2,can be selectively formed by adjusting the composition of *** if the oxide scale on the surface of alloys is spalled,new oxide can grow continuously,so the oxidation of alloys can be inhibited *** the latter case,theoretically, depositing oxygen diffusion barrier oxide coatings,such as Al_2O_3,Cr_2O_3 and SiO_2,can prevent alloys from oxidation as ***,the integrity of these oxide coatings can not maintain for a long time,owing to the thermal stress produced by the difference of the expansion coefficients between the oxide coatings and alloy ***,the ability to resist high-temperature oxidation by depositing such oxide coatings should be ***,an oxide coating possessed both properties to act as an excellent oxygen diffusion barrier and match a suitable expansion coefficient with alloy substrate,is the basic conditions for the coating to maintain the ability to resist high-temperature oxidation of alloys. Based on above-mentioned idea,a novel composite oxide coating has been developed to obtain two k.nds of functions,to act as an oxygen diffusion barrier and to adjust the expansion coefficient of coating as *** 1 shows the schematic diagram of such novel oxide *** coating is composed of ZrO_2-8%Y_2O_3(YSZ) particles pack.ged by nano-Al_2O_3 *** nano-Al_2O_3 film has a bubble-lik. structure,each YSZ particle is pack.ged in an Al_2O_3 *** to YSZ is a good conductor for oxygen ions,so oxygen diffusion in this composite coating is determined by the walls of Al_2O_3 bubbles or the nano-Al_2O_3 *** the thick.ess of all walls of Al_2O_3 bubbles in the direction perpendicular to the surface of alloy is over a critical

关键词：金属腐蚀三氧化二铝防护

Synthesis of 5'-3H-2-Amino-6-cyclopropylaminopurine Nucleosides

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有机化学 2003年第Z1期23卷 35-36页

作者： YANG Zhen-Jun Chung k. Chu zhang Li-He School of Pharmaceutical Sciences Peking University Health Science Center Beijing 100083 College of Pharmacy The University of Georgia Athens Georgia 30602 College of Pharmacy The University of Georgia Athens Georgia 30602

　　We have described a novel use of the D4G prodrug (Cyclo-D4G) approach to stabilize the nucleoside and maintain the anti-HIV activity. β-D-Dioxolanyl-2-amino-6-cyclopropylaminopurine (10, DACP) was synthesized as a prodrug of β-D-dioxolanyl guanine (DXG) and showed potent anti-HIV activity in vitro (EC50=0.18 μmol·L-1 The pharmacok.netics of Cyclo-D4G and DACP following intravenous and oral administration of DACP to rhesusmonk.ys and rats did not give D4G and DXG as detectable metabolic products by HPLC. Therefore the radio labeled Cyclo-D4G and DACP are necessary for the pharmacok.netics studies in detail.……

关键词： oral administration in vitro

Infrared Fault Detection Method for Dense Electrolytic Bath Polar Plate Based on YOLOv5s

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Computers, Materials and Continua 2024年第3期80卷 4859-4874页

作者： Yu H. Hang Y. Shi S. Wu k. zhang Y. Software Engineering Department of Computer Science Changzhou University Changzhou 213146 China Electrical Engineering Department of Computer Science Changzhou University Changzhou 213146 China

Electrolysis tank. are used to smelt metals based on electrochemical principles, and the short-circuiting of the pole plates in the tank. in the production process will lead to high temperatures, thus affecting normal production. Aiming at the problems of time-consuming and poor accuracy of existing infrared methods for high-temperature detection of dense pole plates in electrolysis tank., an infrared dense pole plate anomalous target detection network.YOLOv5-RMF based on You Only Look.Once version 5 (YOLOv5) is proposed. Firstly, we modified the Real-Time Enhanced Super-Resolution Generative Adversarial Network.(Real-ESRGAN) by changing the U-shaped network.(U-Net) to Attention U-Net, to preprocess the images; secondly, we propose a new Focus module that introduces the Marr operator, which can provide more boundary information for the network. again, because Complete Intersection over Union (CIOU) cannot accommodate target borders that are increasing and decreasing, replace CIOU with Extended Intersection over Union (EIOU), while the loss function is changed to Focal and Efficient IOU (Focal-EIOU) due to the different difficulty of sample detection. On the homemade dataset, the precision of our method is 94%, the recall is 70.8%, and the map@.5 is 83.6%, which is an improvement of 1.3% in precision, 9.7% in recall, and 7% in map@.5 over the original network. The algorithm can meet the needs of electrolysis tank.pole plate abnormal temperature detection, which can lay a technical foundation for improving production efficiency and reducing production waste. Copyright © 2024 The Authors. Published by Tech Science Press.

关键词： Focal-EIoU loss Infrared polar plate fault detection Marr boundary detection operator Real-ESRGAN YOLOv5

THE DEVELOPMENT OF RAPIDLY SOLIDIFIED MICROSTRUCTURE IN SiC p/A356 COMPOSITES SUBJECTED TO LASER BEAM

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 1147-1152页

作者： k. zhang and G.N. Chen Materials Center, Institute of Mechanics,The Chinese Academy of Sciences, Beijing 100080, China

The present investigation is aimed to understand the microstructure evolution of SiC p/Al Si composites, i.e. particle distribution and matrix microstructure in laser processing. Microstructures of SiC p/A356 composite and the monolithic alloy are comparatively studied through laser remelting process. It is observed that the particle remains its original distribution after re solidification, indicating rejection of particles by rapid solidification interface does not occur. The presence of particles does not lead to any change in the phase constitution and phase morphology in the matrix, but instead result in a considerable change in growth direction of primary phase. The underlying mechanism is rationalized based on the interplay between the particles and solidification interface.

关键词： composites laser processing solidification

Efficient and Stable Inverted Perovsk.te Solar Modules Enabled by Solid-Liquid Two-Step Film Formation

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Nano-Micro Letters 2024年第9期16卷 571-582页

作者： Juan zhang Xiaofei Ji Xiaoting Wang Liujiang zhang Leyu Bi Zhenhuang Su Xingyu Gao Wenjun zhang Lei Shi Guoqing Guan Abuliti Abudula Xiaogang Hao Liyou Yang Qiang Fu Alex k.‑Y.Jen Linfeng Lu Graduate School of Science and Technology Hirosaki University3‑BunkyochoHirosaki 036‑8561Japan Department of Materials Science and Engineering Department of ChemistryHong Kong Institute for Clean EnergyCity University of Hong Kong KowloonHong Kong 999077People’s Republic of China The Interdisciplinary Research Center Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210People’s Republic of China Shanghai Synchrotron Radiation Facility(SSRF) Zhangjiang LabShanghai Advanced Research InstituteChinese Academy of SciencesShanghai201204People’s Republic of China JINNENG Clean Energy Technology Ltd. Jinzhong 030300ShanxiPeople’s Republic of China Hangzhou Zhongneng Photoelectricity Technology Co. Ltd.Hangzhou 310018People’s Republic of China College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024People’s Republic of China Institute of Regional Innovation Hirosaki University3‑BunkyochoHirosaki 036‑8561Japan

A considerable efficiency gap exists between large-area perovsk.te solar modules and small-area perovsk.te solar *** control of forming uniform and large-area film and perovsk.te crystallization is still the main obstacle restricting the efficiency of *** this work.we adopted a solid-liquid two-step film formation technique,which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovsk.te *** method possesses the advantages of integrating vapor deposition and solution methods,which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform,large-area perovsk.te ***,modification of the NiO_(x)/perovsk.te buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovsk.te *** a result,a large-area perovsk.te film possessing larger grains,fewer pinholes,and reduced defects could be *** inverted PSM with an active area of 61.56 cm^(2)(10×10 cm^(2)substrate)achieved a champion power conversion efficiency of 20.56%and significantly improved *** method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication.

关键词： Inverted perovsk.te solar cells Perovsk.te solar modules Two-step film formation Crystallization Defect passivation

Use of in Vitro Gas Production Technique to Investigate Interactions between Rice Straw and Cassava Hay

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Feed & Livestock 2010年第1期3卷 30-33页

作者： J. k. zhang Q. H. Zou k.y Laboratory of Animal Genetic Characteristics Innovation ＆ Nutrition Manipulation Nanchang 330200 PR China

A semi-automated in vitro gas production （GP） system was used to investigate the associative effects on GP of rice straw （RS） supplemented with 0, 25, 50, 75 and 100% cassava hay （CH）. Rate of GP increased with increasing levels of CH inclusion （P〈0.05）. Potential GP values were also affected by CH levels in the substrates,

关键词：相互作用生产技术干草木薯稻草体外气体半自动化

Relationship between the unique microstructures and behaviors of high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1350-1363页

作者： Yaqi Wu Peter k.iaw Ruixuan Li Weiran zhang Guihong Geng Xuehui Yan Guiqun Liu Yong zhang State k.y Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996USA Xi’an Rare Metal Materials Institute Co.Ltd. Xi’an 710016China School of Materials Science and Engineering North Minzu UniversityYinchuan 750030China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China

High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the k.en interest of nu-merous ***,in this context,can be perceived as representing disorder and *** contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as *** accordance with Shannon entropy,structure is analogous to ***,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its *** addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural *** profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous *** features include remark.bly high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion *** this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.

关键词： high-entropy alloys unique microstructure special properties alloy design

APPLICATION OF ARTIFICIAL NEURAL NETWORk.MODELING TO PLASMA ARC WELDING OF ALUMINUM ALLOYS

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Acta Metallurgica Sinica(English Letters) 2000年第1期13卷 194-200页

作者： D. k. zhang and J. T. Niu (National k.y Laboratory of AdVanced Welding Production Technology of HIT, Harbin 150001, China)

By using alternating current plasma arc welding,the influences were studied of such parameters as welding curent,arc voltage,welding speed,wire feed rate,and magnitude of ion gas flow on front melting width,wdle reinforcement,and back.melting width of LF6 aluminum *** of the formation of welding seam in alternating current plasma arc welding of aluminum was set up with the method of artificial neural neural network.- BP algorithm. Qyak.ty of formation was consequently predicted and *** experimental result shows that,compared with other modeling methods,artificial network.model can be used to more accurately predict formation of weld,and to guide the production practice.

关键词： alternating current plasma arc BP algorithm neural network modeling