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Combined Molecular Dynamics Simulation and Rouse Model Analysis of Static and Dynamic Properties of Unentangled Polymer Melts with Different Chain Architectures

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Chinese Journal of Polymer Science 2021年第4期39卷 512-524,I0008页

作者： Pu Yao Lu-kun feng Hong-Xia Guo Beijing National Laboratory for Molecular Sciences Joint Laboratory of Polymer Sciences and MaterialsState Key Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Chain architecture effect on static and dynamic properties of unentangled polymers is explored by molecular dynamics simulation and Rouse mode analysis based on graph *** open chains,although they generally obey ideal scaling in chain dimensions,local structure exhibits nonideal behavior due to the incomplete excluded volume(EV)screening,the reduced mean square internal distance(MSID)can be well described by Wittmer'theory for linear chains and the resulting chain swelling is architecture dependent,i.e.,the more branches a bit stronger *** rings,unlike open chains they are compact in term of global *** to EV effect and nonconcatenated constraints their local structure exhibits a quite different non-Gaussian behavior from open chains,i.e.,reduced MSID curves do not collapse to a single master curve and fail to converge to a chain-length-independent constant,which makes the direct application of Wittmer's theory to rings quite *** from ideality is further evidenced by limited applicability of Rouse prediction to mode amplitude and relaxation time at high modes as well as the non-constant and mode-dependent scaled Rouse mode amplitudes,while the latter is architecture-dependent and even molecular weight dependent for *** chain relaxation time is architecture-dependent,but the same scaling dependence on chain dimensions does hold for all studied *** mode orthogonality at static state,the role of cross-correlation in orientation relaxation increases with time and the time-dependent coupling parameter rises faster for rings than open chains even at short time scales it is lower for rings.

关键词： Rouse model Unentangled chains Architecture Excluded volume effects

Semi-inclusive lepto-production of hidden-charm exotic hadrons

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Chinese Physics C 2021年第12期45卷 1-7页

作者： Zhi Yang feng-kun Guo School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China CAS Key Laboratory of Theoretical PhysicsInstitute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

We investigate the semi-inclusive production of hidden-charm exotic states,including the X(3872),Z_(c),Zcs and pentaquark P_(c) states,in lepton-proton scattering *** hadrons are close to the thresholds of a pair of charm and anticharm hadrons and are assumed to possess a hadronic molecular structure as their main *** provide order-of-magnitude estimates of the cross sections,we use Pythia to simulate the short-distance productions of the constituent hadrons,which then rescatter to form exotic *** estimates for the X(3872)and Z_(c)(3900)^(±)states are not in conflict with the upper limits measured in the COMPASS experiment for the exclusive photoproduction *** results indicate that the considered hidden-charm states can be copiously produced at the proposed electron-ion colliders EicC and US-EIC.

关键词： hidden-charm exotic hadrons lepto-production

Precise determination of the pole position of the exotic Z_(c)(3900)

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Science China(Physics,Mechanics & Astronomy) 2024年第9期67卷 84-90页

作者： Yun-Hua Chen Meng-Lin Du feng-kun Guo School of Mathematics and Physics University of Science and Technology BeijingBeijing 100083China School of Physics University of Electronic Science and Technology of ChinaChengdu 611731China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Peng Huanwu Collaborative Center for Research and Education Beihang UniversityBeijing 100191China

We perform a unified description of the experimental data of the π^(+)π^(-)and J/ψπ^(±)invariant mass spectra for e^(+)e^(-)→J/ψπ^(+)π^(-)and the D^(0)D^(*-)mass spectrum for e^(+)e^(-)→D^(0)D^(*-)π^(+)at e^(+)e^(-)center-of-mass energies 4.23 and 4.26 *** analysis takes into account open-charm meson loops that contain triangle singularities,the J/ψπ-DD^(*)coupled-channel interaction respecting unitarity,and the strong ππ-KK final state interaction using dispersion *** analysis leads to a precise determination of the Z_(c)(3900)pole with the pole mass and width(3880.7±1.7_(stat)±22.4_(syst))MeV and(35.9±1.4_(stat)±15.3_(syst))MeV,respectively,and hints at that the DD^(*)molecular and non-molecular components are of similar importance in the Z_(c)(3900)formation.

关键词： exotic hadrons dispersion relations final state interaction triangle singularity

Compression techniques of mechanical vibration signals based on optimal sparse representations

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High Technology Letters 2012年第3期18卷 256-262页

作者： feng kun Qin Qiang Jiang Zhinong Diagnosis and Self-Recovery Engineering Research Center Beijing University of Chemical Technology Beijing 100029 P. R. China

This paper presents the result of an experimental study on the compression of mechanical vibration signals. The signals are collected from both rotating and reciprocating machineries by the accelerometers and a data acquisition （DAQ） system. Four optimal sparse representation methods for compression have been considered including the method of frames （ MOF）, best orthogonal basis （ BOB）, matching pursuit （MP） and basis pursuit （BP）. Furthermore, several indicators including compression ratio （CR）, mean square error （MSE）, energy retained （ER） and Kurtosis are taken to evaluate the performance of the above methods. Experimental results show that MP outperforms other three methods.

关键词： signal compression mechanical vibration signals sparse representation matchingpursuit (MP) basis pursuit (BP)

Statics,Dynamics and Linear Viscoelasticity from Dissipative Particle Dynamics Simulation of Entangled Linear Polymer Melts

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Chinese Journal of Polymer Science 2023年第9期41卷 1392-1409,I0007页

作者： Fan Wang Lu-kun feng Ye-Di Li Hong-Xia Guo Beijing National Laboratory for Molecular Sciences Joint Laboratory of Polymer Sciences and MaterialsState Key Laboratory of Polymer Physics and ChemistryInstitute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

Dissipative particle dynamics(DPD)with bond uncrossability shows a great potential in studying entangled polymers,however relatively little is known of applicability range of entangled DPD model to be use as a model for ideal chains and properly describe the full dynamics of entangled ***,we perform a comprehensive study on structure,dynamics and linear viscoelasticity of a typical DPD entangled model system,semiflexible linear polymer *** polymers obey Flory's ideality hypothesis in chain dimensions,but their local structure exhibits nonideal behavior due to weak correlated hole *** monomer motion and viscoelasticity relaxation reproduce the full pictures as predicted by reptation *** stronger chain length dependent diffusion coefficient and relaxation time as well as dynamic moduli are in close agreement with predictions of modern tube model that accounts for additional relaxation mechanisms besides chain ***,an anomalous sub-diffusive center of mass motion is observed both before and after the intermediate reptation regime and the cross-correlation between chains is not negligible even these polymers obey stress-optical law,indicating limitations of the reptation *** semiflexible linear entangled DPD model can correctly describe statics and dynamics of entangled polymer melts.

关键词： Entangled polymer melts Dynamics Linear viscoelasticity Dissipative particle dynamics

Timedelay based all-frequency correction method for discrete spectrum

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High Technology Letters 2011年第1期17卷 106-111页

作者：秦强 Jiang Zhinong He Wei feng kun Diagnosis and Self-recovery Engineering Research Center Beijing University of Chemical Technology Beijing 100029 P. R. China

Many spectrum correction methods have been developed, but their performance degrades significantly when they are applied to the correction of low frequency component （ LFC ）. It owns to that the model underlying the conventional approaches neglects the interference of the negative frequency in the real signal. A new approach for the correction of the LFC is proposed, which suits all kinds of symmetrical windows. It divides a signal into three sections and makes use of the first spectrum line of each section. Then this approach is modified so that it is also applicable to the correction of the high frequency component. Thus a timedelay-based all-frequency correction method is proposed. The simulation results show that this method is simple and feasible. By this method, the accurate frequency, amplitude and phase of the spectral line can be obtained whether it is close to or far from OHz.

关键词： signal analysis fault diagnosis discrete spectrum low frequency spectrum correction

Synthesis and characterization of a novel series of pyrimidinylthiaalkoxycalix[4]arenes

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Chinese Chemical Letters 2007年第4期18卷 403-406页

作者： Bing Zhao Ya Qing feng Yu kun Li School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

A novel series of pyrimidinylthiaalkoxycalix[4]arenes with the reaction between 4,6-dimethylpyrimidine-2-thiol and the different dibromides calix[4]aryl groups have been synthesized and structurally characterized by IR, 1H NMR and MS. From their analysis data, it was found that compounds 8, 9, 11 adopted a cone conformation, while compound 10 existed as a mixture of conformations.

关键词： Pyrimidinylthiaalkoxycalixarenes Synthesis Characterization Conformation

Two New Norsesquiterpenes from Ixeris polycephala

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Chinese Chemical Letters 2006年第7期17卷 913-915页

作者： Yi feng HAN kun GAO Zhong Jian JIA State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000

The chemical investigation of Ixeris polycephala afforded two new norsesquiterpenes, named as ixerols A and B （1-2）. Their structures were established based on spectroscopic methods including 2D NMR experiments. The... 详细信息

关键词： Ixeris polycephala Compositae ixerols A and B norsesquiterpene.

Engineered extracellular vesicles for targeted reprogramming of cancer-associated fibroblasts to potentiate therapy of pancreatic cancer

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Signal Transduction and Targeted Therapy 2024年第7期9卷 3077-3096页

作者： Pengcheng Zhou Xuanlong Du Weilu Jia kun feng Yewei Zhang Department of General Surgery Affiliated Hospital of Nantong UniversityNantongChina School of Medicine Southeast UniversityNanjingChina Nanjing Medical University NanjingChina Hepatobiliary and Pancreatic Center The Second Affiliated Hospital of Nanjing Medical UniversityNanjingChina

Pancreatic cancer is one of the deadly malignancies with a significant mortality rate and there are currently few therapeutic options for *** tumor microenvironment(TME)in pancreatic cancer,distinguished by fibrosis and the existence of cancer-associated fibroblasts(CAFs),exerts a pivotal influence on both tumor advancement and resistance to *** advancements in the field of engineered extracellular vesicles(EVs)offer novel avenues for targeted therapy in pancreatic *** study aimed to develop engineered EVs for the targeted reprogramming of CAFs and modulating the TME in pancreatic *** obtained from bone marrow mesenchymal stem cells(BMSCs)were loaded with miR-138-5p and the anti-fibrotic agent pirfenidone(PFD)and subjected to surface modification with integrinα5-targeting peptides(named IEVs-PFD/138)to reprogram CAFs and suppress their pro-tumorigenic ***α5-targeting peptide modification enhanced the CAF-targeting ability of ***-138-5p directly inhibited the formation of the FERMT2-TGFBR1 complex,inhibiting TGF-βsignaling pathway *** addition,miR-138-5p inhibited proline-mediated collagen synthesis by directly targeting the FERMT2-PYCR1 *** combination of miR-138-5p and PFD in EVs synergistically promoted CAF reprogramming and suppressed the pro-cancer effects of *** experiments using the orthotopic stroma-rich and patient-derived xenograft mouse models yielded promising *** particular,IEVs-PFD/138 effectively reprogrammed CAFs and remodeled TME,which resulted in decreased tumor pressure,enhanced gemcitabine perfusion,tumor hypoxia amelioration,and greater sensitivity of cancer cells to ***,the strategy developed in this study can improve chemotherapy *** IEVs-PFD/138 as a targeted therapeutic agent to modulate CAFs and the TME represents a promising therapeutic approach for pancreatic cancer.

关键词： inhibited targeted chemotherapy