Table of Content

  

20 October 2021
Volume 56 Issue 10

Maximum principle for optimal control of forward-backward stochastic system: full information and partial information

WU Zhen, WANG Guang-chen, LI Min

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  1-10.  doi:10.6040/j.issn.1671-9352.9.2021.012

Abstract ( 1358 )   PDF (1158KB) ( 1077 )   Save

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This paper reviews some progresses on forward-backward stochastic control system. In the past 30 years, various theories and applications of forward-backward stochastic control system have been developed rapidly and a large number of original scientific research results have been obtained, which have attracted many international peers to follow-up research. Limited to the length of this paper and the authors emphasis, this paper only focuses on maximum principle for optimal control of forward-backward stochastic system, and summarizes its latest research progress and application in solving linear quadratic optimal control problem.

Topological structure of graphbased networked evolutionary games

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  11-22.  doi:10.6040/j.issn.1671-9352.9.2021.001

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For a graph-based networked evolutionary game, the strategy evolutional equations for typical nodes are first calculated. A method is proposed to assemble typical node equations together to form the profile evolutional equation. The formula for calculating fixed points and limit cycles of logical networks is applicable to reveal the topological structure of networked evolutionary games, including the fixed points and limit cycles of networked evolutionary games. Next, for each player the unilateral profile updating equation is introduced. Using them, a formula for calculating pure Nash equilibrium(s)is obtained. Some numerical examples are presented.

Topics in Fermat-type functional equations

HU Pei-chu, WU Lin-lin

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  23-37.  doi:10.6040/j.issn.1671-9352.9.2021.003

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In this paper, we introduce some propositions of Fermat-type functional equations.

Two-grid mixed finite element method for incompressible Darcy-Forchheimer miscible displacement problems

RUI Hong-xing, LONG Xin-yu

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  38-47.  doi:10.6040/j.issn.1671-9352.9.2021.007

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In this paper, a two-grid mixed finite element method is used to solve the incompressible miscible displacement problem in porous media, in which the relationship between velocity and pressure conforms to Darcy-Forchheimer law. The purpose of the method is to transform the solving of a large nonlinear system on the fine grid into the solving of a small nonlinear system on the coarse-grid and the solving of a linear system on the fine-grid. The iterative method is needed to solve the nonlinear system. After this transformation only the linear system need to be solved on fine-grid, which can greatly improve the speed of calculation. In the paper, we use piecewise constant element to approximate the velocity and use piecewise continuous linear element to approximate the pressure and concentration. Numerical experiments are carried out to show the error on the fine grid and computational efficiency.

Product and complex structures on Hom-Lie triple systems

CHEN Liang-yun, HOU Ying, MA Yao

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  48-60.  doi:10.6040/j.issn.1671-9352.9.2021.008

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This paper mainly studies two geometric structures on Hom-Lie triple system from the perspective of algebra, named product structure and complex structure. The decomposition of Hom-Lie triple system corresponding to the existence of product structure and complex structure is given respectively. At the same time, some special product structures and complex structures are also studied. Finally, adding a compatibility condition between the two structures in order to obtain the complex product structure.

Oblivious transfer protocols in secure multiparty computation

XU Qiu-liang, JIANG Han, ZHAO Sheng-nan

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  61-71.  doi:10.6040/j.issn.1671-9352.9.2021.009

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Big data and artificial intelligence data processing technology in cloud computing environment bring huge data privacy risks. As a content-based protection, cryptography is the last line of defense of information security. Secure MultiParty Computation can perform the distributed function evaluation under the condition of protecting the input of participants, it has unique advantages in data privacy protection under cloud computing. The core component of Secure MultiParty Computation is the Oblivious Transfer protocol, which plays an important role in all todays Secure MultiParty Computation protocols. Firstly, the principles of various basic Oblivious Transfer protocols in the Secure MultiParty Computation protocols is introduced, which including the Yao garbled circuit and 1 out of 2 Oblivious Transfer protocol, GMW protocol and 1 out of 4 Oblivious Transfer protocol, beaver triple 1 out of 2 Oblivious Transfer protocol. Secondly, the performance optimization technology of Oblivious Transfer protocol is introduced, including precomputing Oblivious Transfer protocol and Oblivious Transfer extension. Thirdly, various variants of Oblivious Transfer are introduced, mainly including Cut and Choose Oblivious Transfer and Cut and Choose Bilateral Oblivious Transfer. Finally, the future research direction of Oblivious Transfer is prospected.

Photoelectric properties of organic chiral molecular devices

XIE Shi-jie, GAO Teng, DU Meng-zhao, LIU Xuan

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  72-78.  doi:10.6040/j.issn.1671-9352.9.2021.002

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At present, many organic chiral molecular devices have been successfully developed, but there are still many unsolved mysteries in their functional mechanism. Among them, the sources of the circular dichroism of chiral molecules and chiral-induced spin selectivity effect are the core of organic chiral molecular researches. To provide the theoretical guidance for the design of new functional organic devices based on chirality, this paper considers the spin-orbit coupling induced by helical potential field of organic chiral molecules to carry out a series of researches on the photoelectric characteristics and regulation of organic chiral molecules. According to the photo-induced transition theory, the optical absorption spectrum and circular dichroism of chiral molecules are obtained. It is found that the optical absorption peak is split, and the circular dichroism is contributed by orbital magnetic moment and spin magnetic moment. In addition, the source of chiral induced spin selectivity effect is explained from the polaron transport picture. Based on its electrical transport characteristics, a chiral heterojunction device is designed. It is found that its chiral resistance is up to 7% and the rectification ratio is up to 48.

Strategies for boosting the catalytic performance of palladium-based electrocatalysts for oxygen reduction reaction

YANG Jun, LIU Dan-ye, ZENG Qing, CHEN Dong, LIU Hui

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  79-98.  doi:10.6040/j.issn.1671-9352.9.2021.006

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Oxygen reduction reaction is the key reaction of many electrochemical devices and technologies, and massive and increasing efforts have been devoted to develop more efficient ORR electrocatalysts in recent decades. Owing to its analogous physical properties to Pt, e.g. phase structure, atomic size and electronic configuration as well as its higher abundance in earth, palladium(Pd)-based nanomaterials, which have been regarded as good substitutes for platinum(Pt), have been extensively studied and their electrocatalytic performance for ORR is continuously improved. Herein, we focus this review on the strategies developed in recent years for boosting the catalytic performance of Pd-based electrocatalysts for ORR, including substrate tailoring, morphological control and composition optimization. These strategies would alter the electronic coupling, ligand effect, lattice strain, and synergistic effect around the Pd atoms, equipping them favorable features for catalyzing oxygen reduction. In the final section of this review, we put forth some perspectives/challenges for further development of Pd-based electrocatalysts, which might be helpful for designing and fabrication of high-efficiency ORR catalysts.

Polysiloxane-based fluorescent materials

FENG Sheng-yu, CHEN Zi-xu, WANG Deng-xu,

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  99-112.  doi:10.6040/j.issn.1671-9352.9.2021.005

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Polysiloxane-based fluorescent materials as a class of organosilicon materials with unique properties have found extensive applications, including fluorescent probes, biosensing, mechanical sensing, and light-emitting diodes. In this review, based on the literatures on polysiloxane-based fluorescent materials at home and abroad and the results from our group in recent decades, the progress in three types of polysiloxane-based fluorescent materials, including linear, hyperbranched, and crosslinked structures, are summarized from the viewpoints of synthesis, applications, and fluorescent mechanism. In particular, the function of polysiloxanes in these fluorescent materials is discussed. Finally, the trend and prospects of polysiloxane-based fluorescent materials are presented.

Bistable solvated dielectron in liquid methylamine: intriguing spin crossover dynamics and dielectron exchanges

BU Yuxiang, LUO Qi

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  113-126.  doi:10.6040/j.issn.1671-9352.9.2021.013

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We present a detailed ab initio molecular dynamics simulation study on solvated dielectron in a type of commonly used liquid medium(liquid methylamine)and reveal unique structures and time evolution dynamics of two excess electrons. We particularly unravel intriguing spin crossover dynamics character of a solvated dielectron which features a bistable bipolaron. Our simulation results indicate that a dielectron in liquid methylamine prefers to accommodate into two independent cavities and evolves non-synchronously with steady dynamics in the singlet state or electron exchange dynamics in the triplet state. More interestingly, both trajectories reveal that the dynamic bipolaron exhibits bistability with frequent spin crossovers between the ferromagnetic and antiferromagnetic states in time evolution. This work presents the first detailed study on the dynamic spin crossover phenomenon of a bistable solvated dielectron in a commonly used liquid medium and provides novel insights into the magnetic liquids for promising applications.

Synthesis and properties of hydrophobic associated cationic polymers and their application in viscosity reduction of heavy oil

TAN Ye-bang, WANG Qiu-xia, GU Lin, LIU Yi-gang, HAN Yu-gui

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  127-134.  doi:10.6040/j.issn.1671-9352.9.2021.010

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The cationic monomer 4-vinylbenzyl dodecyldimethylammonium chloride(VBDDMAC)was synthesized by quatermarization of N,N-dimethyldodecylamine and 4-vinylbenzene, and then the copolymers were prepared by the copolymerization of acrylamide(AM), N-acrylamide morpholine(ACMO)and VBDDMAC. Different copolymers with different monomer ratios were synthesized. The structure of the copolymer was characterized by NMR and IR spectra. The aggregation behavior of the copolymer in aqueous solution was investigated by resonance light scattering. In addition, the interaction between the copolymer and the crude oil was investigated by interfacial tension and contact angle measurement. Finally, the viscosity reduction of the heavy oil was investigated. The results show that the cationic ingredient VBDDMAC makes the copolymer have some emulsifying properties, and the monomer ACMO enhances the interaction between polymer and heavy oil component to greatly reducing the viscosity of heavy oil.

Review and prospect of vegetation research in the Yellow River Delta

WANG Ren-qing, ZHANG Yu-han, SUN Shu-xia, ZHENG Pei-ming

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  135-148.  doi:10.6040/j.issn.1671-9352.9.2021.011

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Ecological protection and high-quality development in the Yellow River Basin have been identified as national strategies. Biodiversity conservation and restoration in the Yellow River Delta is not only an important part of the Yellow River National Strategy, but also the primary task of ecological protection. As an important component and carrier of biodiversity, vegetation is irreplaceable in biodiversity protection. Strengthening the research on vegetation in the Yellow River Delta and exploring its formation, maintenance and evolution mechanism has important academic and practical significance for improving biodiversity, maintaining regional ecological security and sustainable development. Since the 1950s, the ecology discipline of Shandong University has carried out a series of work in the study of vegetation in the Yellow River Delta, involving many aspects, such as vegetation classification, vegetation composition and structural characteristics, vegetation dynamics and degradation, vegetation protection and utilization, and the relationship between vegetation and soil microorganisms. It provides important basic data for the protection of biodiversity and the establishment of nature reserves in the Yellow River Delta and provides a scientific basis for ecological protection and restoration. The vegetation of the Yellow River Delta plays an important role in the construction of national parks and the implementation of the Yellow River national strategy. In the future, the ecology discipline of Shandong University will continue to carry out and strengthen the research on major scientific issues such as the formation, change and maintenance mechanism of vegetation in the Yellow River Delta, so as to provide more powerful scientific and technological support for the ecological protection of the Yellow River and the construction of national parks.

Research on supply chain joint R&D strategy considering the influence of information platform

MENG Qing-chun, YU Yu, JIN Zong-kai, XIE Lei

JOURNAL OF SHANDONG UNIVERSITY(NATURAL SCIENCE). 2021, 56(10):  149-158.  doi:10.6040/j.issn.1671-9352.9.2021.004

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Based on the differences of consumers cognition on the credibility of information platform and product greenness, a Stackelberg game model including a retailer and a manufacturer was built to explore the R&D strategies of green products in supply chain under the influence of information platform, and the advantages and disadvantages of non-joint R&D strategy and two joint R&D strategies were compared and analyzed. The results show that the improvement of the credibility of information platform and the success rate of product R&D can promote the corporate effort and the profit of all parties. By comparing different strategies, it is found that when the revenue sharing ratio is in the middle range, the profit of both retailers and manufacturers under the revenue sharing strategy is better than other strategies. Although the improvement of information platform credibility leads to better manufacturers efforts and retailers profits under revenue sharing strategies, the impact on manufacturers profits and total supply chain profits is not obvious.