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高温下HMX热分解反应分子动力学模拟

原子与分子物理学报 2025年第2期42卷 105-110页

作者：陈芳贾方硕陈瑶李天浩郭国琦董羚中北大学化学与化工学院太原030051

本文采用ReaxFF-lg反应分子动力学方法研究了奥克托金(HMX)在六种不同温度下的初始反应热分解过程,验证了ReaxFF-lg势函数对HMX体系的适用性,计算了不同温度下HMX体系势能、总物种演化趋势、初始反应产物以及指前因子和活化能.结果表明,... 详细信息

本文采用ReaxFF-lg反应分子动力学方法研究了奥克托金(HMX)在六种不同温度下的初始反应热分解过程,验证了ReaxFF-lg势函数对HMX体系的适用性,计算了不同温度下HMX体系势能、总物种演化趋势、初始反应产物以及指前因子和活化能.结果表明,HMX热分解过程主要有三种初始分解机理:N-NO_(2)键的断裂,HONO的解离和主环上C-N键的断裂,计算得到的初始分解阶段活化能Ea和指前因子ln(A),与实验值相吻合.

关键词： HMX 反应分子动力学(RMD) ReaxFF-lg 热分解温度

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Research and application of stochastic resonance in quad-stable potential system

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Chinese Physics B 2022年第7期31卷 169-181页

作者： Li-Fang He Qiu-ling Liu tian-Qi Zhang School of Communication and Information Engineering Chongqing University of Posts and Telecommunications(CQUPT)Chongqing 400065China

To solve the problem of low weak signal enhancement performance in the quad-stable system,a new quad-stable potential stochastic resonance(QSR)is ***,under the condition of adiabatic approximation theory,the stationary probability distribution(SPD),the mean first passage time(MFPT),the work(W),and the power spectrum amplification factor(SAF)are derived,and the impacts of system parameters on them are also extensively ***,numerical simulations are performed to compare QSR with the classical Tri-stable stochastic resonance(CTSR)by using the genetic algorithm(GA)and the fourth-order Runge–Kutta *** shows that the signal-to-noise ratio(SNR)and mean signal-to-noise increase(MSNRI)of QSR are higher than CTSR,which indicates that QSR has superior noise immunity than ***,the two systems are applied in the detection of real bearing *** experimental results show that QSR is superior to CTSR,which provides a better theoretical significance and reference value for practical engineering application.

关键词： bearing fault detection QSR weak signal detection SAF W

Physalin B reduces Aβ secretion through down-regulation of BACE1 expression by activating FoxO1 and inhibiting STAT3 phosphorylation

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Chinese Journal of Natural Medicines 2021年第10期19卷 732-740页

作者： ZHANG Wei BAI Shan-Shan ZHANG Qi SHI Ru-ling WANG He-Cheng LIU you-Cai NI tian-Jun WU Ying YAO Zhao-Yang SUN Yi WANG Ming-Yong School of Basic Medical Sciences Xinxiang Medical UniversityXinxiang 453003China Grade 2019 School of Basic Medical SciencesXinxiang Medical UniversityXinxiang 453003China School of Public Health Xinxiang Medical UniversityXinxiang 453003China School of Life and Pharmaceutical Sciences Dalian University of TechnologyPanjin 124221China School of Basic Medical Sciences Sanquan College of Xinxiang Medical UniversityXinxiang 453003China School of Nursing Care Xinxiang Medical UniversityXinxiang 453003China Institute of Chinese Materia Medica China Academy of Chinese Medical SciencesBeijing 100700China School of Laboratory Medicine Xinxiang Medical UniversityXinxiang 453003China Xinxiang Key Laboratory of Immunoregulation and Molecular Diagnostics Xinxiang 453003China Central Laboratory the First Affiliated Hospital of Henan University of Science and TechnologyLuoyang 471003China

Physalin B(PB),one of the major active steroidal constituents of Solanaceae Physalis plants,has a wide variety of biological *** found that PB significantly down-regulatedβ-amyloid(Aβ)secretion in N2a/APPsw ***,the underlying mechanisms are not well *** the current study,we investigated the changes in key enzymes involved inβ-amyloid precursor protein(APP)metabolism and other APP metabolites by treating N2a/APPsw cells with PB at different *** results indicated that PB reduced Aβ secretion,which was caused by down-regulation of β-secretase(BACE1)expression,as indicated at both the protein and mRNA *** research revealed that PB regulated BACE1 expression by inducing the activation of forkhead box O1(FoxO1)and inhibiting the phosphorylation of signal transducer and activator of transcription 3(STAT3).In addition,the effect of PB on BACE1 expression and Aβsecretion was reversed by treatment with FoxO1 siRNA and STAT3 antagonist *** conclusion,these data demonstrated that PB can effectively down-regulate the expression of BACE1 to reduce Aβsecretion by activating the expression of FoxO1 and inhibiting the phosphorylation of STAT3.

关键词： Physalin B β-amyloid BACE1 FoxO1 Alzheimer’s disease

Preparation of PdCo Bimetallic Hollow Nanospheres and its Electrocatalytic Activity for Oxidation of Formic Acid

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Chinese Chemical Letters 2006年第12期17卷 1623-1626页

作者： Ya Wen TANG Shuang CAO ling ling ZHANG Jian Chun BAO Ping ZHOU tian Hong LU Department of Chemistry Nanjing Normal University Nanjing 210097 Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022

The PdCo bimetallic hollow nanospheres with 80 nm average diameter and around 9.0 nm thickness of the shell were prepared with a special reduction method and characterized with transmission electron microscopy （TEM）, X-ray diffraction （XRD） and energy dispersive spectroscopy （EDS）. The electrochemical measurements illustrated that the electrocatalytic activity of the PdCo bimetallic hollow nanospheres for the oxidation of formic acid is much higher than that of the Pd solid nanospheres.

关键词： PdCo hollow nanosphere catalyst formic acid.

PLG-g-mPEG Mediated Multifunctional Nanoparticles for Photoacoustic Imaging Guided Combined Chemo/Photothermal Antitumor Therapy

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Chinese Journal of Polymer Science 2023年第4期41卷 538-546,I0007页

作者： Chong Liu ling Li Zhao-Pei Guo Lin Lin Yan-Hui Li Hua-Yu tian School of Materials Science and Engineering Changchun University of Science and TechnologyChangchun130022China Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China College of Chemistry and Chemical Engineering Xiamen UniversityXiamen361005China School of Materials Science and Engineering Xiamen University of TechnologyXiamen361024China

Under laser irradiation,photothermal therapy(PTT)effectively ablates tumors above 50℃.However,hyperthermia can cause additional damage due to the inevitable heat spread to surrounding healthy ***,nanoparticles named as GI@P NPs were designed for enhanced PTT with heat shock protein 90(HSP90)inhibition at temperatures below 50℃to achieve optimal cancer therapy and avoid surrounding ***@P NPs were done by co-loading Garcinia cambogia acid(GA)and photosensitizer IR783 in polymer PLG-g-mPEG to form a nanomedicine,where IR783 with excellent photoacoustic(PA)signal acted as an excellent photothermal therapeutic agent that converted the laser energy into heat to kill tumor cells,GA was used as antitumor drug for chemotherapy and an inhibitor of HSP90 to overcome the heat resistance of tumors for efficient cryo-photothermal therapy,and PLG-g-mPEG can encapsulate IR783 and GA to increase biocompatibility and accumulate effectively in the *** GI@P NPs were injected into the mice,we could observe that the PA signals gradually increased in the tumor region and showed the strongest PA signals at 12 *** laser irradiation,the tumor temperature of the mice could raise to about 43.5℃,and the tumor was significantly inhibited after long-term monitoring by PA *** a result,gentle PTT produced by GI@P NPs exhibited good antitumor effects at relatively low temperature and minimized nonspecific thermal damage to normal *** GI@P NPs as nanomedicine enriched our understanding of various applications of polymeric carriers,especially in the biomedical field.

关键词： Mild-temperature photothermal therapy Photoacoustic imaging Polymer carrier Combination therapy Co-loading

Purification efficiency of ecological spur dikes for river pollutants in different geometric arrangements:Experiments and numerical modeling

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Journal of Hydrodynamics 2022年第5期34卷 934-947页

作者： Yi-tian Chen Xiao-ling Wang Song-min Li Ya-zhi Zheng Guang-yao Dong College of Environmental Science and Engineering Tianjin UniversityTianji300350China State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin300072China College of Hydraulic Engineering Tianjin Agricultural CollegeTianjin300392China

The traditional ecological spur dike is improved,by using the biological fillers such as the plant materials,combined with microorganisms,to obtain a larger water purification *** of the researches on spur dikes focused on the hydrodynamic force and the migration and the diffusion of the pollutants,but not so much on the effects of the spur dike materials and the arrangement parameters on the water purification *** this paper the biological zeolite is used to make ecological spur *** laboratory flume experiment shows that compared with the natural zeolite spur dike,the purification effect of the biological zeolite spur dike is significantly improved,and the average removal rate of the NH3-N is kept at 6.8%after 24 h compared with 3.5%of the natural zeolite spur *** NH3-N removal rates of a single spur dike,the counterpart spur dikes and the staggered spur dikes decrease with the increase of the inlet flow,and the staggered spur dikes have the best purification ***,a numerical model based on the MIKE21 is verified by the experimental results and applied for the Tangjiali Section of the Xutangqiao River in Xinwu District,Wuxi City,Jiangsu *** orthogonal test shows that the length of the spur dike has the most important effect on the interception of pollutants and the purification,followed by the angle of the spur dike and the spacing of the spur dikes has the least important *** geometric arrangement parameters of the ecological spur dike group with the highest efficiency on the pollutant interception and the purification are:60°(angle),6.7 m(length)and 20 m(spacing).

关键词： Ecological spur dike spur dike group numerical simulation biological zeolite interception purification geometric arrangement parameters

Ultrastable nickel single-atom catalysts with high activity and selectivity for electrocatalytic CO_(2)methanation

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Nano Research 2023年第7期16卷 8987-8995页

作者： ling-Chan tian Jin-Nian Hu Yang Meng Jin-Xia Liang Chun Zhu Jun Li School of Chemistry and Chemical Engineering Guizhou UniversityGuiyang 550025China Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry Southern University of Science and TechnologyShenzhen 518055China Department of Chemistry and Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education Tsinghua UniversityBeijing 100084China

Electrochemical conversion of CO_(2)into valuable hydrocarbon fuel is one of the key steps in solving carbon emission and energy ***,we report a non-noble metal catalyst,nickel single-atom catalyst(SAC)of Ni_(1)/UiO-66-NH_(2),with high stability and selectivity for electrochemical reduction of CO_(2)to CH_(4).Based on ab initio molecular dynamics(AIMD)simulations,the CO_(2)molecule is at first reduced into CO_(2)-when stably adsorbed on a Ni single atom with the bidentate coordination *** evaluate its activity and selectivity for electrocatalytic reduction of CO_(2)to different products(HCOOH,CO,CH3OH,and CH_(4))on Ni_(1)/UiO-66-NH_(2),we have used density functional theory(DFT)to study different reaction *** results show that CH_(4) is generated preferentially on Ni_(1)/UiO-66-NH_(2)and the calculated limiting potential is as low as-0.24 ***,the competitive hydrogen evolution reaction is unfavorable at the activation site of Ni_(1)/UiO-66-NH_(2)owing to the higher limiting potential of-0.56 ***,the change of Ni single atom valence state plays an important role in promoting CO_(2)reduction to CH_(4).This work provides a theoretical foundation for further experimental studies and practical applications of metal-organic framework(UiO-66)-based SAC electrocatalysts with high activity and selectivity for the CO_(2)reduction reaction.

关键词： single atom catalyst density functional theory CO_(2)reduction metal-organic framework electrocatalysis

An experimental study on fracture mechanical behavior of rock-like materials containing two unparallel fissures under uniaxial compression

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Acta Mechanica Sinica 2016年第3期32卷 442-455页

作者： Yan-Hua Huang Sheng-Qi Yang Wen-ling tian Wei Zeng Li-Yuan Yu State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology

Strength and deformability characteristics of rock with pre-existing fissures are governed by cracking behavior. To further research the effects of pre-existing fissures on the mechanical properties and crack coalescence process, a series of uniaxial compression tests were carried out for rock-like material with two unparallel *** the present study, cement, quartz sand, and water were used to fabricate a kind of brittle rock-like material cylindrical model specimen. The mechanical properties of rock-like material specimen used in this research were all in good agreement with the brittle rock materials. Two unparallel fissures（a horizontal fissure and an inclined fissure） were created by inserting steel during molding the model *** all the pre-fissured rock-like specimens were tested under uniaxial compression by a rock mechanics servocontrolled testing system. The peak strength and young＇s modulus of pre-fissured specimen all first decreased and then increased when the fissure angle increased from 0？to 75？.In order to investigate the crack initiation, propagation and coalescence process, photographic monitoring was adopted to capture images during the entire deformation ***, acoustic emission（AE） monitoring technique was also used to obtain the AE evolution characteristic of prefissured specimen. The relationship between axial stress, AE events, and the crack coalescence process was set up： when a new crack was initiated or a crack coalescence occurred, thecorresponding axial stress dropped in the axial stress–time curve and a big AE event could be observed ***, the mechanism of crack propagation under microscopic observation was discussed. These experimental results are expected to increase the understanding of the strength failure behavior and the cracking mechanism of rock containing unparallel fissures.

关键词： Rock-like material Two unparallel fissures Mechanical parameters Crack evolution Acoustic emission(AE)

Effect of low-temperature ausforming on bainitic transformation and mechanical properties in ultrahigh-strength bainitic steel

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Journal of Iron and Steel Research International 2023年第9期30卷 1843-1853页

作者： tian-yu Zhang ling-yu Wang Yu Wang Jun Hu Hong-shuang Di Wei Xu State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

Low-temperature ausforming(LT-AF)prior to bainitic transformation leads to a noticeable acceleration of bainitic transformation kinetics;however,the effect of LT-AF on the retained austenite(RA)features and the resulting mechanical properties is still ***-AF was applied to ultrahigh-strength bainitic steel before *** deformation behavior and the resulting dislocation substructures were investigated by thermomechanical simulator and transmission electron microscopy(TEM).The planar dislocation structures produced during deformation at 350℃ accelerate the bainitic transformation kinetics during isothermal *** effect of LT-AF on the bainitic transformation kinetics and the features of RA was elucidated via dilatometer measurement,TEM,scanning electron microscopy,and X-ray *** is observed that LT-AF not only retains more RA content but also facilitates improved RA *** trend is mainly due to the large amounts of planar dislocations in RA and bainitic laths inherited from undercooled austenite caused by LT-AF,the decrease in bainitic sheaves size,and the increase in filmy RA content compared to the sample without ausforming.A large fraction of filmy RA with high stability and the refinement of bainitic sheaves obtained by LT-AF remarkably enhance the strain hardening capacity and achieve significantly better ductility compared to the directly austempered sample.

关键词： Ultrahigh-strength bainitic steel Bainitic transformation Low-temperature ausforming Retained austenite Strain hardening rate