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Optimality Conditions for Generalized Convex Nonsmooth Uncertain Multi-objective Fractional Programming

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Journal of the Operations Research Society of China 2023年第4期11卷 809-826页

作者： Xiao Pan Guo-Lin Yu Tian-Tian Gong School of Mathematics and Information Science North Minzu UniversityYinchuan750021NingxiaChina

This paper aims at studying optimality conditions of robust weak efficient solutions for a nonsmooth uncertain multi-objective fractional programming problem(NUMFP).The concepts of two types of generalized convex function pairs,called type-I functions and pseudo-quasi-type-I functions,are introduced in this paper for(NUMFP).Under the assumption that(NUMFP)satisfies the robust constraint qualification with respect to Clarke subdifferential,necessary optimality conditions of the robust weak efficient solution are *** optimality conditions are obtained under pseudo-quasi-type-I generalized convexity ***,we introduce the concept of robust weak saddle points to(NUMFP),and prove two theorems about robust weak saddle *** main results in the present paper are verified by concrete examples.

关键词： Multi-objective fractional programming Robust weak efficient solution Generalized convex function Optimality condition Saddle point

Design and synthesis of ZnCo_(2)O_(4)/CdS for substantially improved photocatalytic hydrogen production

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Frontiers of Chemical Science and Engineering 2023年第5期17卷 606-616页

作者： Xiaohong Li Youji Li Xin Guo Zhiliang Jin School of Chemistry and Chemical Engineering North Minzu UniversityYinchuan 750021China College of Chemistry and Chemical Engineering Jishou UniversityJishou 416000China

In this study,the hydrogen evolution performance of CdS nanorods is improved using ZnCo_(2)O_(4).ZnCo_(2)O_(4)nanospheres are synthesized using the hydrothermal and calcination methods,and CdS nanorods are synthesized using the solvothermal *** the perspective of morphology,numerous CdS nanorods are anchored on the ZnCo_(2)O_(4)*** to the experimental results of photocatalytic hydrogen evolution,the final hydrogen evolution capacity of 7417.5μmol·g^(-1)·h^(-1)is slightly more than two times that of the single CdS,which proves the feasibility of our *** various characterization methods,it is proved that the composite sample has suitable optoelectronic *** addition,ZnCo_(2)O_(4)itself exhibits good conductivity and low impedance,which shortens the charge-transfer ***,the introduction of ZnCo_(2)O_(4)expands the adsorption range of light and improves the performance of photocatalytic hydrogen *** design can provide reference for developing high-efficiency photocatalysts.

关键词： ZnCo_(2)O_(4)nanosphere CdS nanorods photocatalytic hydrogen evolution

Image edge detection based on pulse coupled neural network and modulus maxima in non-subsampled contourlet domain

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The Journal of China Universities of Posts and Telecommunications 2018年第3期25卷 55-64页

作者： Hu Ling Chang Xia Qian Wei School of Mathematics and Information Science North Minzu University

Edge is the intrinsic geometric structure of an image. Edge detection methods are the key technologies in the lleld of image processing. In this paper, a multi-scale image edge detection method is proposed to effectively extract image geometric features. A source image is decomposed into the high frequency directional sub-bands coefficients and the low frequency sub-bands coefficients by non-subampled contourlet transform （NSCT）. The high frequency sub-bands coefficients are used to detect the abundant details of the image edges by the modulus maxima （MM） algorithm. The low frequency sub-band coefficients are used to detect the basic contour line of the image edges by the pulse coupled neural network （PCNN）. The final edge detection image is reconstructed with detected edge information at different scales and different directional sub-bands in the NSCT domain. Experimental results demonstrate that the proposed method outperforms several state-of-art image edge detection methods in both visual effects and objective evaluation.

关键词： edge detection modulus maxima pulse coupled neural network wavelet transform non-subsampled contourlet transform

Higher-order Optimality Conditions and Duality for Approximate Solutions in Non-convex Set-valued Optimization

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Acta Mathematicae Applicatae Sinica 2019年第3期35卷 620-628页

作者： Guo-lin YU Tian-tian GONG north minzu university

This paper deals with higher-order optimality conditions and duality theory for approximate solutions in vector optimization involving non-convex set-valued ***,under the assumption of near cone-subconvexlikeness for set-valued maps,the higher necessary and sufficient optimality conditions in terms of Studniarski derivatives are derived for local weak approximate minimizers of a set-valued optimization ***,applications to Mond-Weir type dual problem are presented.

关键词： studniarski derivatives optimality conditions set-valued optimization problem efficiency duality

Performance of Ni-Cu bimetallic co-catalyst g-C3N4 nanosheets for improving hydrogen evolution

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Journal of Materials Science & Technology 2020年第14期47卷 144-156页

作者： Zhiliang Jin Lijun Zhang School of Chemistry and Chemical Engineering North Minzu UniversityYinchuan 750021China Ningxia Key Laboratory of Solar Chemical Conversion Technology North Minzu UniversityYinchuan 750021China Key Laboratory for Chemical Engineering and Technology State Ethnic Affairs CommissionNorth Minzu UniversityYinchuan 750021China

The Ni-Cu bimetallic nanoparticles were successfully anchorred on the surface of g-C3N4 nanosheets by a simple heat treatment process which was applied to the photocatalytic hydrogen evolution *** introduction of Ni-Cu could significantly improve the photocatalytic hydrogen evolution performance compared with pure g-C3N4 in the system sensitized by eosin Y under a visible irradiation *** hydrogen production activity of the composite reached 104.4μmol(2088.28μmol g^-1 h^-1)after using the Ni Cu double promoter strategy,which was 24.3 times higher than *** excellent electrical conductivity of the bimetallic Ni-Cu and the close interfacial contact between Ni Cu and g-C3N4 played an important role for increasing the charge transfer *** were also the reasons of more efficient charge separation,which ultimately led to a significant promotion on the photocatalytic hydrogen production ***-Cu/g-C3N4 coupling with a close Schottky interface between metal and semiconductor which enhanced H2-evolution performance and TEOA oxidation *** work provided a new way to load Ni Cu bimetallic nanoparticles in situ onto g-C3N4 and a reference on relative semiconductor materials.

关键词： Bimetallic Ni-Cu g-C3N4 Charge separation Hydrogen evolution

Study on the flow structure in curved open channels with suspended vegetation using multi relaxation time lattice Boltzmann method

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Journal of Hydrodynamics 2024年第2期36卷 300-315页

作者： He-fang Jing Qiao-ling Zhang Wei-hong Wang Zong-ning Zhang School of Mathematics and Information Science North Minzu UniversityYinchuan750021China School of Civil Engineering North Minzu UniversityYinchuan750021China Department of Basic Courses Zhengzhou University of Science and TechnologyZhengzhou450064China

Suspended vegetation in rivers,lakes,reservoirs and canals can change flow structure,which will in turn affect the sediment transport and cause the variation of water ecological *** order to study the characteristics of bend flow through suspended vegetation,three-dimensional numerical simulations are carried out by using the multi-relaxation-time lattice Boltzmann method(MRT-LBM).The drag force induced by vegetation is added in the velocity correction in the equilibrium distribution and a hybrid format combined bounce and specular reflection scheme is applied in the solid-fluid *** the validation of this model,six cases are designed to conduct the numerical simulations according to the root depth and the arrangement of *** simulated results show that the suspended vegetation can redistribute the flow structure in curved open *** the arrangement of suspended vegetation,the main flow moves to the side without vegetation,and the distribution of velocity tends to be balanced when vegetation is arranged on the entire cross section,the range of circulating current is reduced from the whole cross section to the local position without vegetation,however,the circulating current can still exist in the curve where the suspended vegetation enters less than half of the water *** addition,it can also be concluded that the suspended vegetation can affect the lateral gradient of flow velocity,and the bed shear stress in the curved channel.

关键词： Multi-relaxation-time lattice Boltzmann method(MRT-LBM) suspended vegetation curved open channel circulating current bed shearstress

Hopf bifurcation of nonlinear system with multisource stochastic factors

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Theoretical & Applied Mechanics Letters 2023年第2期13卷 93-97页

作者： Xinyu Bai Shaojuan Ma Qianling Zhang Qiyi Liu School of Mathematics and Information Science North Minzu UniversityYinChuanNingXia 750021China

The article mainly explores the Hopf bifurcation of a kind of nonlinear system with Gaussian white noise excitation and bounded random ***,the nonlinear system with multisource stochastic fac-tors is reduced to an equivalent deterministic nonlinear system by the sequential orthogonal decomposi-tion method and the Karhunen-Loeve(K-L)decomposition ***,the critical conditions about the Hopf bifurcation of the equivalent deterministic system are *** the same time the influence of multisource stochastic factors on the Hopf bifurcation for the proposed system is ***,the theorical results are verified by the numerical simulations.

关键词： Multisource stochastic factors Gaussian white noise K-L decomposition Hopf bifurcation Random parameter

Controllable design of Zn-Ni-P on g-C_3N_4 for efficient photocatalytic hydrogen production

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Chinese Journal of Catalysis 2019年第3期40卷 390-402页

作者： Yanbing Li Zhiliang Jin Lijun Zhang Kai Fan School of Chemistry and Chemical Engineering North Minzu University Yinchuan 750021 Ningxia China Key Laboratory for Chemical Engineering and Technology State Ethnic Affairs Commission North Minzu University Yinchuan 750021 Ningxia China

Synthesizing a stable and efficient photocatalyst has been the most important research goal up to now. Owing to the dominant performance of g-C3N4 (graphitized carbonitride), an ordered assemble of a composite photocatalyst, Zn-Ni-P@g-C3N4, was successfully designed and controllably prepared for highly efficient photocatalytic H2 evolution. The electron transport routes were successfully adjusted and the H2 evolution was greatly improved. The maximum amount of H2 evolved reached about 531.2 μmol for 5 h over Zn-Ni-P@g-C3N4 photocatalyst with a molar ratio of Zn to Ni of 1:3 under illumination of 5 W LED white light (wavelength 420 nm). The H2 evolution rate was 54.7 times higher than that over pure g-C3N4. Moreover, no obvious reduction in the photocatalytic activity was observed even after 4 cycles of H2 production for 5 h. This synergistically increased effect was confirmed through the results of characterizations such as XRD, TEM, SEM, XPS, N2 adsorption, UV-vis DRS, transient photocurrent, FT-IR, transient fluorescence, and Mott-Schottky studies. These studies showed that the Zn-Ni-P nanoparticles modified on g-C3N4 provide more active sites and improve the efficiency of photogenerated charge separation. In addition, the possible mechanism of photocatalytic H2 production is proposed.

关键词： Zn-Ni-P g-C3N4 H2 production Controllable design Photocatalyst

Computational Insights into the Excited State Intramolecular Proton Transfer Reactions in Ortho-hydroxylated Oxazolines

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Chinese Journal of Structural Chemistry 2021年第5期40卷 540-548,527页

作者： LIU Gai-Mei MA Wei-Jia WANG Yan YANG Yan SONG Xin-Jian School of Chemistry and Environmental Engineering Hubei Minzu UniversityEnshi 445000China Key Laboratory of Magnetic Resonance in Biological Systems National Center for Magnetic Resonance in WuhanState Key Laboratory of Magnetic Resonance and Atomic and Molecular PhysicsWuhan Institute of Physics and MathematicsChinese Academy of SciencesWuhan 430071China

Excited-state intramolecular proton transfer(ESIPT) reactions of three ortho-hydroxylated oxazolines, 2-(4,4-dimethyl-4,5-dihydro-oxazol-2-yl)-phenol(DDOP), 4-(4,4-dimethyl-4,5-dihydro-oxazol-2-yl)-[1,1?-biphenyl]-3-ol(DDOP-C_(6)H_(5)) and 4-(4,4-dimethyl-4,5-dihydrooxazol-2-yl)-3-hydroxy-benzonitrile(DDOP-CN), have been systematically explored by density functional theory(DFT) and time-dependent density functional theory(TDDFT) methods. Two stable configurations(enol and keto forms) are found in the ground states(S_(0)) for all the compounds while the enol form only exists in the first excited states(S_(1)) for the compound modified with electron donating group(-C_(6)H_(5)). In addition, the calculated absorption and emission spectra of the compounds are in good agreements with the experiments. Infrared vibrational spectra at the hydrogen bond groups demonstrate that the intramolecular hydrogen bond O(1)-H(2)···N(3) in DDOP-C_(6)H_(5) is strengthened in the S_(1) states, while the frontier molecular orbitals further reveal that the ESIPT reactions are more likely to occur in the S_(1) states for all the compounds. Besides, the proton transfer potential energy curves show that the enol forms can barely convert into keto forms in the S_(0) states because of the high energy barriers. Meanwhile, intramolecular proton transfer of all the compounds could occur in S_(1) states. The ESIPT reactions of the ortho-hydroxylated oxazolines are barrierless processes for unsubstituted DDOP and electron withdrawing substituted DDOP-CN, while the electron donating substituted DDOP-C_(6)H_(5) has a small barrier, so the electron donating is unfavorable to the ESIPT reactions of ortho-hydroxylated oxazolines.

关键词： excited-state intramolecular proton transfer electron donating group ortho-hydroxylated oxazolines potential energy curves