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Reactive molecular dynamics insight into the thermal decomposition mechanism of 2,6-Bis(picrylamino)-3,5-dinitropyridine

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Defence Technology（防务技术） 2024年第3期33卷 134-146页

作者： Jianbo fu Hui Ren Xinzhou Wu Yongjin chen Mi Zhang Yazhi cheng State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

2,6-bis(picrylamino)-3,5-dinitropyridine(PYX)has excellent thermostability,which makes its thermal decomposition mechanism receive much *** this paper,the mechanism of PYX thermal decomposition was investigated thoroughly by the ReaxFF-lg force field combined with DFT-B3LYP(6-311++G)*** detailed decomposition mechanism,small-molecule product evolution,and cluster evolution of PYX were mainly *** the initial stage of decomposition,the intramolecular hydrogen transfer reaction and the formation of dimerized clusters are earlier than the denitration *** the progress of the reaction,one side of the bitter amino group is removed from the pyridine ring,and then the pyridine ring is *** final products produced in the thermal decomposition process are CO_(2),H_(2)O,N_(2),and H_(2).Among them,H_(2)O has the earliest generation time,and the reaction rate constant(k_(3))is the *** clusters are formed during the decomposition of PYX,and the formation,aggregation,and decomposition of these clusters are strongly affected by *** low temperatures(2500 K-2750 K),many clusters are *** high temperatures(2750 K-3250 K),the clusters aggregate to form larger *** 3500 K,the large clusters decompose and become *** the late stage of the reaction,H and N in the clusters escaped almost entirely,but more O was trapped in the clusters,which affected the auto-oxidation process of ***'s initial decomposition activation energy(E_(a))was calculated to be 126.58 kJ/*** work contributes to a theoretical understanding of PYX's entire thermal decomposition process.

关键词： PYX Thermal decomposition ReaxFF-lg MD simulations Excellent thermostable explosives

Study on the clogging mechanism of punching screen in sand control by the punching structure parameters

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Petroleum Science 2024年第1期21卷 609-620页

作者： fu-cheng Deng fu-Lin Gui Bai-Tao Fan Lei Wen Sheng-Hong chen Ning Gong Yun-chen Xiao Zhi-Hui Xu Yangtze University Jingzhou434023HubeiChina CNOOC Research Institute Ltd. Beijing100028China CNOOC Ener Tech-Drilling&Production Co. Tianjin300457China Tianjin Branch of CNOOC Ltd. Tianjin300459China

As an independent sand control unit or a common protective shell of a high-quality screen,the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and gas ***,most screens only consider the influence of the internal sand retaining medium parameters in the sand control performance design while ignoring the influence of the plugging of the punching screen on the overall sand retaining performance of the *** explore the clogging mechanism of the punching screen,this paper established the clogging mechanism calculation model of a single punching screen sand control unit by using the computational fluid mechanics-discrete element method(CFD-DEM)combined *** to the combined motion of particles and fluids,the influence of the internal flow state on particle motion and accumulation was *** results showed that(1)the clogging process of the punching sand control unit is divided into three stages:initial clogging,aggravation of clogging and stability of *** the initial stage of blockage,coarse particles form a loose bridge structure,and blockage often occurs preferentially at the streamline gathering place below chamfering inside the sand control *** the stage of blockage intensification,the particle mass develops into a relatively complete sand bridge,which develops from both ends of the opening to the center of the *** the stable plugging stage,the sand deposits show a“fan shape”and form a“V-shaped”gully inside the punching slot element.(2)Under a certain reservoir particle-size distribution,The slit length and opening height have a large influence on the permeability and blockage rate,while the slit width size has little influence on the permeability and blockage *** microscopic clogging mechanism and its law of the punching screen prevention unit are proposed in this study,which has some field guidance significance for the design of punching screen

关键词： Punching screen Plugging CFD-DEM Size parameter Sand control

Preparation of yttrium oxide coating with enhanced thermal shock resistance on refractories used for titanium alloy melting and casting

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Journal of Iron and Steel Research International 2024年第6期31卷 1411-1422页

作者： Ao chen Yan Ma Zhou-fu Wang Hao Liu Xi-tang Wang Sen-na chen chen-xin Zhang Zi-yi Tang Wei-dong fu Wei cheng The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Xiangyang Juli High Technology Material Co. Ltd.Xiangyang 441705HubeiChina Xiangyang Public Inspection and Testing Center Xiangyang 441000HubeiChina

In order to enhance the service life of refractories for melting and casting of titanium alloy,preparation of yttrium oxide coatings on the refractories surface is an effective *** improvement of thermal shock stability of the coating is beneficial to its spalling resistance during the high-temperature service,and the available slurry with good performance is the *** effects of the varieties and contents of dispersant(sodium tripolyphosphate,sodium hexametaphosphate,sodium pyrophosphate,citric acid and polycarboxylate ammonium salt)and binder(aluminum dihydrogen phosphate,zirconium acetate and yttria sol)on the stability,rheological and thixotropic properties of yttrium oxide waterbased slurry were investigated,and the effects of slurry composition design on the thermal shock resistance of the coating were *** results showed that the introduction of polycarboxylate ammonium salt as dispersant significantly improved the stability of the slurry,and the varieties of the binders had significant effects on the dispersibility of the *** aluminum dihydrogen phosphate and polycarboxylate ammonium salt were used as binder and dispersant,respectively,the slurry had better stability,suitable rheological and thixotropic *** using aluminum dihydrogen phosphate as binder,the coating had good thermal shock resistance and no obvious cracks were observed for the coating after thermal shock,which was attributed to the yttrium aluminate binding phase generated in the *** effective method was provided for preparing yttrium oxide coatings with enhanced thermal shock resistance applied in the process of titanium alloy melting and casting.

关键词： Yttrium oxide-Slurry Stability Rheological property Thixotropic property-Coating Thermal shock resistance

Probing the electric double layer structure at nitrogen-doped graphite electrodes by constant-potential molecular dynamics simulations

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Journal of Energy Chemistry 2024年第6期93卷 299-305,I0008页

作者： Legeng Yu Nan Yao Yu-chen Gao Zhong-Heng fu Bo Jiang Ruiping Li cheng Tang Xiang chen Tsinghua Center for Green Chemical Engineering Electrification(CCEE) Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China National Materials Corrosion and Protection Data Center University of Science and Technology BeijingBeijing 100083China Ordos Carbon Neutral Research and Application Co. Ltd.Ordos 017010Inner Mongoli1China Institute for Carbon Neutrality Tsinghua UniversityBeijing 100084China Center for Next-Generation Energy Materials and School of Chemical Engineering Sungkyunkwan University2066 Seobu-roJangan-guSuwon-siGyeonggi-do 16419Republic of Korea

Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium ***,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very ***,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an *** interface model was developed,incorporating the electrode potential and atom *** a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following electrochemical reactions at the atomic ***,the negatively charged N atoms repel the anions and adsorb Li~+at high and low potentials,*** preferential adsorption suggests that Ndoped graphite can promote Li~+desolvation and regulate the location of Li~+*** CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.

关键词： Lithium batteries Graphite N-doping Electric double layer Molecular dynamics Constant potential method Electrode potential

Enhancing the electrochemical performance of Na metal anodes via local eutectic melting in porous Al-Cu alloy hosts

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Nano Research 2024年第7期17卷 6111-6118页

作者： Tao Hu Qiang Wu cheng Wang Jialu chen fu Su Zibo chen Yizhou Wang Jianyu chen Yanwen Ma Jin Zhao State Key Laboratory of Organic Electronics and Information Displays&Institute of Advanced Materials(IAM) Nanjing University of Posts&Telecommunications9 Wenyuan RoadNanjing 210023China Materials Science and Engineering King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia Suzhou Vocational Institute of Industrial Technology 1 Zhineng AvenueSuzhou International Education ParkSuzhou 215104China

Sodium(Na)metal batteries(SMBs)have emerged as promising alternatives to lithium metal batteries for large-scale energy storage applications,owing to their cost-effectiveness,abundance,and favorable redox ***,the practical implementation of SMBs faces several challenges associated with the Na metal anode,including the formation of dendrites,low Coulombic efficiency,and capacity ***,we propose a novel approach to enhance the electrochemical performance of Na metal anodes through a porous Al-Cu alloy host(PAC)fabricated by a local eutectic melting *** local eutectic melting facilitates the development of a conductive network,offering mechanical support,and the porous structure provides abundant channels for the diffusion of Na ions and accommodates volume fluctuations in the Na metal during charge–discharge ***,the PAC exhibits a high average Coulombic efficiency of 99.8%at 1 mA·cm^(−2)for 1 mAh·cm^(−2)and a low voltage polarization of 19 mV during 500 *** study provides valuable insight into the design and fabrication of highperformance Na metal anodes,which hold significant promise for the advancements of next-generation energy storage systems.

关键词： Na metal anode porous Al-Cu alloy porous current collector local eutectic melting

p38 Signaling Mediates Naringin-Induced Osteogenic Differentiation of Porcine Metanephric Mesenchymal Cells

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Chinese Journal of Integrative Medicine 2024年第9期30卷 818-825页

作者： JI Peng-cheng XIE Yuan-sheng GUO Wen-kai fu Bo chen Xiang-mei Chinese PLA Medical School Beijing100853China Department of Nephrology First Medical Center of Chinese PLA General HospitalChinese PLA Institute of NephrologyState Key Laboratory of Kidney DiseasesNational Clinical Research Center for Kidney DiseasesBeijing Key Laboratory of Kidney DiseasesBeijing100853China School of Medicine Nankai UniversityTianjin300071China

Objective:To explore the potential of metanephric mesenchymal cells(MMCs)for osteogenesis and naringin’s ability to enhance this process and its molecular ***:Porcine MMCs at 70 days of gestation were used as tool cells,cultured in osteogenic induction medium,identified by immunocytochemistry *** potential of porcine MMCs and naringin’s ability to enhance this process was tested by detecting changes in cell viability,alkaline phosphatase(ALP)activity,the expression of runt-related transcription factor 2(Runx2),osteopontin(OPN)and osteocalcin(OCN),and the formation of mineralized nodules,and the application of the p38 signaling pathway inhibitor SB203580 vitiated the osteogenesis-promoting effect of ***:Immunocytochemical staining showed that the cells were Vimentin and Six2(+),E-cadherin and CK-18(−).Naringin can activate the p38 signaling pathway to enhance the osteogenesis of porcine MMCs by increasing cell viability,ALP activity,the expressions of Runx2,OPN and OCN,and the formation of mineralized nodules(P<0.05).The application of p38 signaling pathway inhibitor SB203580 vitiated the osteogenesis-promoting effect of naringin,manifested by decreased ALP activity,the expressions of Runx2,OPN and OCN,and the formation of mineralized nodules(P<0.05).Conclusion:Naringin,the active ingredient of Chinese herbal medicine Rhizoma Drynariae for nourishing Shen(Kidney)and strengthening bone,enhances the osteogenic differentiation of renal MMCs through the p38 signaling pathway.

关键词： metanephric mesenchymal cells naringin osteogenesis differentiation

Essential oil of Actinidia macrosperma, a catnip response kiwi endemic to China

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2006年第9期7卷 708-712页

作者： ZHAO Yun-peng WANG Xiao-yun WANG Zhi-can LU Yin fu cheng-xin chen Shao-yuan Research Program for Medicinal Plant Resource Lab of Systematic ＆ Evolutionary Botany and Biodiversity School of Life Sciences Zhejiang University Hangzhou 310058. China

Objective: To identify compounds that may be responsible for catnip response of Actinidia macrosperma, and compare chemical compositions in the wild and in vitro regenerated plants. Methods: GC-MS and relative retention indices with n-alkanes as reference points were used for compound identification, and component relative percentage was calculated based on GC peak areas without using correction factors. Results: There are 28 compounds (92.72%) and 15 compounds (93.88%) identi- fied in the essential oils from the wild and regenerated plants, respectively. Dihydronepetalactone, iridomyrmecin, and dihydro- actinidiolide, which are believed to be attractive to felines, are present in both wild and regenerated plants. Actinine was not detected, and beta-pheylethyl alcohol was only present in wild plant. In addition, short-chain enol derivatives, messengers in chemical communication, are commonly present in wild plant of A. macrosperma, but absent in regenerated one. Conclusion: Dihydronepetalactone, iridomyrmecin, and dihydroactinidiolide are responsible for the catnip response of A. macrosperma.

关键词： Actinidia macrosperma GC-MS Dihydronepetalactone lridomyrmecin Dihydroactinidiolide Catnip response

Evaluation of 3D crustal seismic velocity models in southwest China:Model performance,limitation,and prospects

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Science China Earth Sciences 2024年第2期67卷 604-619页

作者： Xin WANG Ling chen Qi-fu chen Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China

Southwest China is a tectonically and seismically active region,witnessing strong deformation due to the collision between the Indian and Eurasian *** the subsurface velocity structure of this region is thus important in understanding the tectonics and geodynamic processes of continental collision and in mitigating seismic *** studies have provided various 3D seismic velocity models in southwest ***,discrepancies exist among these models,and less effort has been made to quantify the reliability and accuracy of these existing velocity *** this study,we use regional 3D waveform simulation to evaluate the performance of various regional crustal 3D velocity models in reproducing observed *** particularly focus on two recent earthquake sequence in the region,the 2021 Yunnan Yangbi MS_(6.4) earthquake sequence and the 2022 Sichuan Luding MS_(6.8) earthquake *** tested 3D velocity models include the Southwest China Community Velocity model V1.0,the Unified Seismic Tomography Models for Continental China Lithosphere V2.0,the adjoint full waveform tomography model of the crustal and upper mantle beneath Eastern Tibetan Plateau,and the shallow seismic structure model beneath continental *** results show that the tested 3D velocity models generally capture well long-period(full-waveform tomography model shows a slighter better performance than the other models,especially for the body-waves,highlighting the advantages

关键词： Southwest China Seismic tomography models Shallow Structures Waveform simulation Model evaluation

Effect of micro-Al_(2)O_(3) powders on oxidation and corrosion behaviors of low-carbon MgO-C refractories

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Journal of Iron and Steel Research International 2024年第6期31卷 1522-1534页

作者： Yang chen Zeng-yi Li Hao-bo Tan Yu-ran fu Jun Ding cheng-ji Deng Chao Yu School of Materials Science and Engineering Hunan Institute of TechnologyHengyang 421002HunanChina The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

To solve the problem of poor high-temperature service performance caused by low carbonization of MgO-C refractories,low-carbon MgO–C refractories with excellent thermal shock,oxidation and corrosion resistances were successfully designed by using SiC whiskers as reinforcing phases and introducing micro-Al_(2)O_(3) powders as *** results indicated that the addition of micro-Al_(2)O_(3) powders optimized the internal structure of the material,like the columnar β-Si_(3)N_(4) with a stepped distribution and the mosaic structure formed between granular and flaky Mg_(2)SiO_(4),which synergistically strengthened and toughened the material and gave the material excellent mechanical properties and thermal shock ***,the cold modulus of rupture and cold crushing strength after thermal shock were increased by 4.1 and 20.3 MPa,***,the addition of micro-Al_(2)O_(3) powders promoted the formation of fine particles of Mg_(2)SiO_(4),MgAl_(2)O_(4) and MgO,as well as a dense protective layer of Mg_(2)SiO_(4) in the material under high-temperature ***,spinel and high-temperature solid solution were formed in the corrosion *** oxidation and corrosion resistances were greatly improved by 41%and 15%,respectively.

关键词： Low-carbon MgO-C refractory Oxidation resistance Corrosion resistance Thermal shock resistance Micro-Al_(2)O_(3)powder