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An Efficient Algorithm for Self-consistent Field Theory Calculations of Complex Self-assembled Structures of Block Copolymer Melts

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Chinese Journal of Polymer Science 2018年第4期36卷 488-496页

作者： Jun-Qing Song Yi-Xin Liu hong-dong zhang State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Fudan University

Self-consistent field theory（SCFT）, as a state-of-the-art technique for studying the self-assembly of block copolymers, is attracting continuous efforts to improve its accuracy and efficiency. Here we present a fourth-order exponential time differencing Runge-Kutta algorithm（ETDRK4） to solve the modified diffusion equation（MDE） which is the most time-consuming part of a SCFT calculation. By making a careful comparison with currently most efficient and popular algorithms, we demonstrate that the ETDRK4 algorithm significantly reduces the number of chain contour steps in solving the MDE, resulting in a boost of the overall computation efficiency, while it shares the same spatial accuracy with other algorithms. In addition, to demonstrate the power of our ETDRK4 algorithm, we apply it to compute the phase boundaries of the bicontinuous gyroid phase in the strong segregation regime and to verify the existence of the triple point of the O70 phase, the lamellar phase and the cylindrical phase.

关键词： Block copolymer Self-consistent field theory Algorithm Pseudo-spectral Phase structure

Force-Extension Curve of an Entangled Polymer Chain:A Superspace Approach

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Chinese Journal of Polymer Science 2021年第11期39卷 1345-1350页

作者： Huan Gong Jian-Feng Li hong-dong zhang An-Chang Shi The State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai 200433China School of Computer Science and Technology Fudan UniversityHamiltonOntario Canada L8S 4M1 Department of Physics and Astronomy Mc Master UniversityShanghai 200433China

The statistical mechanics of an ideal polymer chain entangled with static topological constraints is studied using a superspace approach,in which the probability distribution of the polymer is obtained as solutions of the Fokker-Planck equation in a superspace with an inner structure characterized by the n-generator free *** theory predicts that the force-extension curve of the polymer under the topological constraints has the generic form F=kl+Z/l,where l is an effective *** from the elastic term that is linear in l,the forceextension curve contains a universal term of the form Z/*** magnitude of this topological term is determined by the topological charge number Z,which characterizes the topological nature of the static *** theoretical results are further verified by a scaling analysis based on a blob model of the chain conformations.

关键词： Topological constraints Probability distribution Polymer entanglement

Kinetic Pattern Formation with Intermolecular Interactions:A Modified Brusselator Model

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Chinese Journal of Polymer Science 2021年第12期39卷 1673-1679页

作者： Rui-Qi Sun Jian-Feng Li hong-dong zhang Yu-Liang Yang Department of Macromolecular Science State Key Laboratory of Macromolecular Engineering of PolymersFudan UniversityShanghai 200438China

In this work,we modify the traditi onal Brusselator model to in corporate the intermolecular interactions,based on which a systematic study is performed on the pattern formation mediated by chemical reaction and phase *** is found that if the chemical reaction dominates,the pattern formation will be inhibited by the phase separation while if the phase separation dominates,the chemical reaction will preve nt,un der certain conditi ons,the domain size from growing which results in dissipative patter ns other tha n macroscopic phase separations.

关键词： Brusselator model Regular solution Phase separation

Designs to Improve Capability of Neural Networks to Make Structural Predictions

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Chinese Journal of Polymer Science 2023年第9期41卷 1477-1485,I0009页

作者： Tian-Yao Wang Jian-Feng Li hong-dong zhang Jeff Z.Y.Chen Department of Macromolecular Science State Key Laboratory of Macromolecular Engineering of PolymersFudan UniversityShanghai200438China Department of Physics and Astronomy University of WaterlooWaterlooN2L 3G1Canada

A deep neural network model generally consists of different modules that play essential roles in performing a *** optimal design of a module for use in modeling a physical problem is directly related to the success of the *** this work,the effectiveness of a number of special modules,the self-attention mechanism for recognizing the importance of molecular sequence information in a polymer,as well as the big-stride representation and conditional random field for enhancing the network ability to produce desired local configurations,is numerically *** models containing these modules are trained by using the well documented data of the native structures of the HP model and assessed according to their capability in making structural predictions of unseen *** specific network design of self-attention mechanism adopted here is modified from a similar idea in natural language *** big-stride representation module introduced in this work is shown to drastically improve network's capability to model polymer segments of strong lattice position correlations.

关键词： Deep neural network Self-attention mechanism Big-stride representation Conditional random methods

AN EXPERIMENTAL INVESTIGATION OF PRESSURE AND CAVITATION CHARACTERISTICS OF HIGH VELOCITY FLOW OVER A CYLINDRICAL PROTRUSION IN THE PRESENCE AND ABSENCE OF AERATION

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Journal of Hydrodynamics 2008年第1期20卷 60-66页

作者： dong Zhi-yong LIU Zhi-ping WU Yi-hong zhang dong China Hydraulic and Municipal Engineering Research Institute Zhejiang University of Technology Hangzhou 310014 China Institute of Water Resources and Hydroelectric Power Research Beijing 100038 China

This article experimentally investigated the pressure and cavitation characteristics of high velocity flow over a surface irregularity with and without aeration in a non-circulating water tunnel system. The surface irregularity is a cylindrical protrusion made of stainless steel of 6 mm diameter and 2 mm height. Pressures with and without aeration were measured with MPX400D pressure transducers and real-timely acquired by a SINOCERA YE6263 data acquisition system. Variations in flow regimes with and without aeration were observed. Pressure profiles and their variations with air concentration upper and lower cylindrical protrusion on the invert and obvert walls were determined. Variations of cavitation number with air concentration lower cylindrical protrusion were analyzed. Also, cavitation numbers in the presence and absence of aeration were compared.

关键词： cylindrical protrusion aeration pressure cavitation number high velocity flow

Research on Bast Fiber Extracted from the White Bark of Three Species in the Genus Broussonetia

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Chinese Journal of Polymer Science 2024年第6期42卷 729-738页

作者： Shan-Shan Jin Si-Nong Wang Yan-Yan Huang Jing-Yu zhang Peng Liu Hui Yu hong-dong zhang Yu-Liang Yang Institute for Preservation and Conservation of Chinese Ancient Books Fudan University LibraryFudan UniversityShanghai200433China State key laboratory of Molecular Engineering of polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China

Against the backdrop of a global paper resource shortage,there is a growing need to identify fast-growing tree species capable of producing long-lasting *** plant species namely Broussonetia kazinoki,Broussonetia papyrifera and hybrid paper mulberry,belong to the Broussonetia genus,were collected from China to study their white bark suitability for pulp and *** chemical composition revealed that the holocellulose content in Broussonetia kazinoki and Broussonetia papyrifera was more than 80%.The molecular weight distribution of several holocellulose/α-cellulose is observed by GPC,which allows us to better observe the changes of various components on the molecular *** yield,lignin,whiteness,and molecular weight of the pulps obtained by NaOH treatment were *** microscope was used to characterize the fiber length-width ratio and ***,the improvement of the fiber rigidity method based on the Kratky-Porod chain model makes it more theoretical and further reveals the influencing factors of fiber *** study demonstrates the high potentiality of these three species for papermaking applications.

关键词： Broussonetia genus Cellulose Alkaline pulping Kratky-Porod chain model Fiber rigidity

Fiber Bending Flexibility Evaluation by Worm-like Chain Model

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Chinese Journal of Polymer Science 2022年第5期40卷 526-531页

作者： Chao Jin Hui Yu Chun-Fang Wu Hai-Bo Zhao Shan-Shan Jin Yu-Liang Yang hong-dong zhang Institute for Preservation and Conservation of Chinese Ancient Books Fudan UniversityShanghai 200433China Statekey laboratory of Molecular Engineering of polymers Department of Macromolecular ScienceFudan UniversityShanghai 200433China

A new method for characterizing fiber bending flexibility was developed by worm-like chain model proposed by Kratky-Porod,[1]which was first introduced to the pulp and paper field in this *** the three types of pulps,the experimental results were compared with the KP chain model,and the resulting determination coefficients were all above 0.95,which proved that the model was feasible to be applied to these three *** relation between fiber bending rigidity and that of cellulosic chains inside was discussed to deduce the fiber bending *** flexibility of an individual fiber can be approximated as the contribution of that of all the cellulose chains *** this method,the fiber flexibility values were determined to be in the range of 0.6×10^(11)-3.5×10^(11)N^(-1)·m^(-2),which was comparable to that of the conventional methods recorded in the literature.

关键词： Worm-like chain Fiber persistence length Fiber bending flexibility

EPG Comparison of Sitobion avenae (Fab.) Feeding Behavior on Three Wheat Varieties

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Agricultural Sciences in China 2008年第2期7卷 180-186页

作者： HU Xiang-shun ZHAO Hui-yan HU Zu-qing LI dong-hong zhang Yu-hong College of Plant Protection Northwest A＆F University Yangling 712100 P.R.China

This article was to study the potential resistance mechanism of three different wheat varieties （Ww2730, Xiaoyan 22 and Batis） in the seedling stage to Sitobion avenae. The aphid feeding behavior was ascertained by stylet penetration activities monitoring using the electrical penetration graph （EPG） technique. When the aphids feed on Ww2730 seedlings, the time for the 1st duration probing was later than that on Xiaoyan 22 and Batis significantly, and the number of interrupted probing before the 1st duration probing was more than that on Xiaoyan 22 and Batis significantly, and the 1st duration probing was shorter than that on Xiaoyan 22 and Batis significantly. The durations of the stylet pierce from the extra- to the intra-cellular （pd Ⅱ-1） on Ww2730 and Xiaoyan 22 were longer than those on Batis significantly. The duration of the potential drop （pd） in C wave on Ww2730 was longer than that on Xiaoyan 22 and Batis significantly. The times and duration of the G wave （ingestion in xylem） on Ww2730 were more and longer than those on Xiaoyan 22 and Batis significantly. The times of spot G wave on Batis was more than that on Ww2730 significantly, but the duration of spot G was shorter than that on Xiaoyan 22 and Ww2730 significantly. The total time of E1 wave, the longest duration of E1 fractions, and the mean duration time of E1 fractions that followed E2 wave on Xiaoyan 22 and Batis were all significantly longer than those on Ww2730. There was no difference of the mean duration of the 1st E1 wave on the 3 varieties, but the mean durations of other E1 wave on Ww2730 and Xiaoyan 22 were shorter than those on Batis significantly. The other wave parameters, including times and durations of F and E2 were all not different on the 3 wheat varieties. It is suggested that the resistance mechanism of wheat variety Ww2730 to S. avenae is a restriction factor of feeding in epidermis, the thicker cell wall in mesophyll, and secondary metabolites or nutrition unbalance in phloem in

关键词： wheat Sitobion avenae resistance mechanism electrical penetration graph (EPG) feeding behavior

Factors influencing intercellular spaces in the rat esophageal epithelium

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World Journal of Gastroenterology 2010年第9期16卷 1063-1069页

作者： dong-hong zhang,Li-Ya Zhou,Xiu-Yun dong,Rong-Li Cui,Yan Xue,San-Ren Lin,Department of Gastroenterology,Peking University Third Hospital,Beijing 100191,China Department of Gastroenterology Peking University Third Hospital No. 49 Huayuanbei Road Beijing 100191 China. liyazhou@***

AIM:To evaluate the effect of acute stress,hydrochloric acid,ethanol,aspirin,and prednisolone on the intercellular spaces of the esophageal ***:Part -RESULTS:(1) The f ive damaging factors produced no lesions or inflammation in esophageal mucosa of rats under either gross or routine histological *** epithelial intercellular space diameters in stress and aspirin groups were significantly greater,nearly three or two-fold respectively,than those in their corresponding control groups (stress model:0.38 ± 0.05 μm vs 0.13 ± 0.02 μm,P 0.05;ethanol model:0.25 ± 0.10 μm vs 0.19 ± 0.05 μm,P > 0.05;prednisolone model:0.20 ± 0.03 μm vs 0.14 ± 0.03 μm,P > 0.05);and (2) No significant difference in the intercellular space diameters was observed between the group pretreated with esomeprazole and the control group,in both the stress and aspirin models (stress model:0.35 ± 0.05 μm vs 0.37 ± 0.05 μm,P > 0.05;aspirin model:0.24 ± 0.02 μm vs 0.27 ± 0.03 μm,P > 0.05).CONCLUSION:Acute stress and aspirin can induce DIS of the esophageal epithelium in rats,and it is not correlated with acid reflux.

关键词： Esophagus Dilated intercellular spaces Stress,acute Aspirin Reflux,acid