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Translocation of Polymer Chains Through a Channel with Complex Geometries

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Chinese Journal of Chemical Physics 2008年第6期21卷 555-559页

作者： Zhi-yong Yang lin-xi zhang Jun Cheng Department of Physics Wenzhou University Wenzhou 325027 China

The elastic behavior of a single chain transporting through complex channel which can be seen as the combination of three different channels （left channel, middle channel, and right channel, respectively） is investigated using the new pruned-enriched Rosenbluth method with importance sampling. The elastic force during the translocation process is calculated. At the entrance into the middle channel, there is the first plateau in the curve of the elastic force f （f〉0） versus x, here x represents the position of the first monomer along the x-axis direction. When the first monomer moves to a certain position, a second plateau is observed with the elastic force f〈0, which represents spontaneous translocation. The free energy difference between the subchain in the right channel and the subchain in the left channel may drive the transloeation. The influence of chain length and width of the left and right channels on the translocation process are also investigated. From the simulation results, more detailed explanations for the reason why the component translocation time is not the same for different channels can be presented.

关键词： Elastic behavior nPERMis Polymer translocation

RATE OF INTRAMOLECULAR CONTACT FORMATION IN PROTEINS

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维普期刊数据库

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Chinese Journal of Polymer Science 2007年第2期25卷 197-201页

作者： lin-xi zhang Ting-ting Sun xiang-hong Wang Department of Physics Wenzhou University Wenzhou 325027 China Department of Physics Zhejiang University Hangzhou 310027 China

In this paper, we estimate the rate of contact formation between two residues in the interior of the proteins using the Szabo, Schulten, and Schulten formula with the probability distribution P（r） based on 375 proteins from PDB （Protein Data Bank）. The probability distribution for residue pair in proteins is different from the Gaussian distribution, especially for short distance between two residues in proteins. The rate of contact formation in the interior of protein is discussed as a function of distance n （=｜j -i｜） between two residues, and it decreases monotonically with n and follows the scaling relationship of k ∝ n^-γ with γ= 1.43 for the contact radius a = 0.40 nm and γ=1.05 for a = 0.50 nm. The diffusion coefficient for the relative diffusion of two residues in the interior of proteins is estimated as D = 6.4 × 10^-6 cm^2/s, which is close to the result that is found for monomer diffusion.

关键词： Rate of intramolecular contact formation Probability distribution P(r).

Controllable laning phase for oppositely driven disk systems

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Chinese Physics B 2019年第12期28卷 123-129页

作者： lin Liu Ke Li xiao-lin Zhou lin-Li He lin-xi zhang Department of Physics Zhejiang UniversityHangzhou 310027China Department of Physics Wenzhou UniversityWenzhou 325035China

A two-dimensional binary driven disk system embedded by impermeable tilted plates is investigated through nonequilibrium computer simulations. It is well known that a binary disk system in which two particle species are driven in opposite directions exhibits jammed, phase separated, disordered, and laning states. The presence of tilted plates can not only advance the formation of laning phase, but also effectively stabilize laning phase by suppressing massively drifting behavior perpendicular to the driving force. The lane width distribution can be controlled easily by the interplate distance. The collective behavior of driven particles in laning phase is guided by the funnel-shaped confinements constituted by the neighboring tilted plates. Our results provide the important clues for investigating the mechanism of laning formation in driven system.

关键词： driven system tilted plates laning phase drifting behavior

SELF-ASSEMBLY OF linEAR TRIBLOCK COPOLYMERS UNDER CYlinDRICAL NANOPORE CONFINEMENTS

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Chinese Journal of Polymer Science 2013年第1期31卷 122-138页

作者： Wen-juan Qiu 李士本 Yong-yun Ji lin xi zhang Department of Physics Wenzhou University Department of Physics Zhejiang University

The self-assembly of linear ABC triblock copolymers under cylindrical confinements is investigated in two- dimensional space using the real-space self-consistent field theory. The effects of confinement degrees and preferential strengths on the triblock copolymer phase behaviors with special polymer parameters are first considered. On one hand, different confinement degrees cause different phase behaviors in nanopores with the neutral surfaces. Moreover, the strongly preferential surface fields can surpass the confinement degrees and volume fractions in determing the confined phase behaviors. On the other hand, in contrast, confined morphologies are more sensitive to the variations in the A-preferential surface field strength. Subsequently, the incompatibility degrees between different blocks are systematically varied under cylindrical nanopore confinements. Under cylindrical nanopore confinements, the morphologies are very sensitive to the variations in the incompatibility degrees. Meanwhile, nanopore confinements can affect order-disorder and order-order transition points in the bulk. The corresponding free, internal, and entropic energies as well as the order parameters are also quantificationally examined to deeply investigate the confined phase mechanisms, and a number of morphological transitions are confirmed to be of first-order. These findings may guide the design of novel nanostructures based on triblock copolymers by introducing confinements.

关键词： Triblock copolymers Cylindrical confinements Self-assembly Self-consistent field theory.

Conformational Behavior of Single Circular Semiflexible Polyelectrolyte in the Presence of Multivalent Counterions

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Chinese Journal of Polymer Science 2023年第3期41卷 448-458,I0010页

作者： Zhi-Yong Yang Wen-Long lin Ai-Hua Chai Dan Lu Nian-Qian Kang lin-xi zhang Department of Physics Jiangxi Agricultural UniversityNanchang 330045China Lucheng College Wenzhou PolytechnicWenzhou 325006China College of data science Jiaxing UniversityJiaxing 314001China Department of Physics Zhejiang UniversityHangzhou 310027China

Langevin dynamics simulations are employed to explore the effects of chain stiffness and electrostatic interaction(EI) on the conformational behavior of a circular semiflexible polyelectrolyte(CSPE) in presence of trivalent *** investigate the effect of bending energy b and the dimensionless Bjerrum length A on the conformational behavior of the CSPE with a fixed chain *** competition among the EIs,chain stiffness and entropy of the system leads to rich conformations for the *** the b is less than or equal to 50,The shape of the CSPE changes from a oblate ring to a rod at small A,then to a toroid at intermediate A,and finally to a globule at very large ***,the globular conformation is not observed for large *** addition,we find that the number of torus ring increases with A increase,while decreases with b *** study should be helpful in gaining insight into the conformational behaviour of charged biopolymer.

关键词： Langevin dynamics simulation Circular semiflexible polyelectrolyte Trivalent counterions Electrostatic interaction

A study of gentamicin injury mechanisms using cultured mouse cochlear spiral ganglion cells

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Journal of Otology 2011年第1期6卷 31-35页

作者： GU xi lin Chang zhang Rong Department of Otolaryngology-Head and Neck Surgery First Affiliated Hospital of Fujian Medical University Fuzhou Fujian 350005 China

Objective To study gentamicin injury mechanisms using postnatal mouse cochlear spiral gangcells （SGC）. Methods SGCs were isolated using a combinatorial approach of enzymatic digestion and mechanical separation from P2 - 6 Kunming mouse cochleae. After 4 days, cultured SGCs were fixed with 4% paraformaldehyde at room temperature for immunocytochemical examination using the methods of S-P and the monoclonal antibody against mouse neurofilament protein （Neurofilament-68/200Kda, NF-L＋ H）. SGCs were randomly divided into a blank control group and three gentamicin treatment groups （medium gentamicin concentration at 50 mg/L, 100 mg/L and 150 mg/L respectively）, SGCs were collected and examined under a transmission electron microscope after being cultured for 48 h. Results SGC primary culture was successful. SGC cytoplasm and neurites were dyed brownish yellow by the monoelonal mouse neurofilament protein antibody. SGCs showed classical bipolar neuron appearance. Under the transmission electron microscope,.gentamicin treated SGCs showed morphological features different compared to those in the blank control group, which might indicate apoptosis. Conclusion Our results indicate that gentamicin has direct toxic effects on cochlear SGCs in mice and the injury mechanism is closely related with apoptosis. Damage to mitochor, dria may play an important role in the process.

关键词： gentamicins spiral ganglion cells, cultured microscopy electron transmission apoptosis

Partial flow blockage analysis of the hottest fuel assembly in SNCLFR-100 reactor core

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Nuclear Science and Techniques 2018年第1期29卷 110-117页

作者： Kang-Li Shi Shu-Zhou Li xi-lin zhang Peng-Cheng Zhao Hong-Li Chen School of Nuclear Science and Technology University of Science and Technology of China

In this paper, we perform an unprotected partial flow blockage analysis of the hottest fuel assembly in the core of the SNCLFR-100 reactor, a 100 MW_(th) modular natural circulation lead-cooled fast reactor, developed by University of Science and Technology of China. The flow blockage shall cause a degradation of the heat transfer between the fuel assembly and the coolant potentially,which can eventually result in the clad fusion. An analysis of core blockage accidents in a single assembly is of great significance for LFR. Such scenarios are investigated by using the best estimation code RELAP5. Reactivity feedback and axial power profile are considered. The crosssectional fraction of blockage, axial position of blockage,and blockage-developing time are discussed. The cladding material failure shall be the biggest challenge and shall be a considerable threat for integrity of the fuel assembly if the cross-sectional fraction of blockage is over 94%. The blockage-developing time only affects the accident progress. The consequence will be more serious if the axial position of a sudden blockage is closer to the core *** method of analysis procedure can also be applied to analyze similar transient behaviors of other fuel-type reactors.

关键词： Transient analysis Flow blockage LFR Natural circulation RELAP5 code

Flexible and Robust Functionalized Boron Nitride/Poly(p‑Phenylene Benzobisoxazole)Nanocomposite Paper with High Thermal Conductivity and Outstanding Electrical Insulation

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Nano-Micro Letters 2024年第2期16卷 423-437页

作者： lin Tang Kunpeng Ruan xi Liu Yusheng Tang Yali zhang Junwei Gu Chongqing Key Laboratory of Green Synthesis and Applications College of ChemistryChongqing Normal UniversityChongqing 401331People’s Republic of China Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China

With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming *** this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation *** obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered ***λ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),***,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.

关键词： Poly(p-phenylene-2,6-benzobisoxazole)nanofiber Boron nitride Thermal conductivity Electrical insulation

Pupillometry Analysis of Rapid Serial Visual Presentation at Five Presentation Rates

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Tsinghua Science and Technology 2024年第2期29卷 543-552页

作者： xi Luo Yanfei lin Rongxiao Guo xirui Zhao Shangen zhang xiaorong Gao School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China School of Medicine Tsinghua UniversityBeijing 100084China

In this study,the effect of presentation rates on pupil dilation is investigated for target recognition in the Rapid Serial Visual Presentation(RSVP)*** this experiment,the RSVP paradigm with five different presentation rates,including 50,80,100,150,and 200 ms,is *** pupillometry data of 15 subjects are collected and *** pupillometry results reveal that the peak and average amplitudes for pupil size and velocity at the 80-ms presentation rate are considerably higher than those at other presentation *** average amplitude of pupil acceleration at the 80-ms presentation rate is significantly higher than those at the other presentation *** latencies under 50-and 80-ms presentation rates are considerably lower than those of 100-,150-,and 200-ms presentation ***,no considerable differences are observed in the peak,average amplitude,and latency of pupil size,pupil velocity,and acceleration under 100-,150-,and 200-ms presentation *** results reveal that with the increase in the presentation rate,pupil dilation first increases,then decreases,and later reaches *** 80-ms presentation rate results in the largest point of pupil *** correlation is observed between pupil dilation and recognition accuracy under the five presentation rates.

关键词： pupil dilation presentation rate Rapid Serial Visual Presentation(RSVP)