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Molecular Dynamics Simulation of Shock Response of CL-20 Co-crystals Containing Void Defects

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Defence Technology（防务技术） 2024年第1期31卷 364-374页

作者： Changlin Li Wei Yang Qiang Gan Yajun Wang lin Liang Wenbo Zhang Shuangfei Zhu Changgen feng State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Materials Science&Engineering Beijing Institute of TechnologyBeijing 100081China

To investigate the effect of void defects on the shock response of hexanitrohexaazaisowurtzitane(CL-20)co-crystals,shock responses of CL-20 co-crystals with energetic materials ligands trinitrotoluene(TNT),1,3-dinitrobenzene(DNB),solvents ligands dimethyl carbonate(DMC) and gamma-butyrolactone(GBL)with void were simulated,using molecular dynamics method and reactive force *** is found that the CL-20 co-crystals with void defects will form hot spots when impacted,significantly affecting the decomposition of molecules around the *** degree of molecular fragmentation is relatively low under the reflection velocity of 2 km/s,and the main reactions are the formation of dimer and the shedding of nitro *** existence of voids reduces the safety of CL-20 co-crystals,which induced the sensitivity of energetic co-crystals CL-20/TNT and CL-20/DNB to increase more *** has occurred under the reflection velocity of 4 km/s,energetic co-crystals are easier to polymerize than solvent co-crystals,and are not obviously affected by *** results show that the energy of the wave decreases after sweeping over the void,which reduces the chemical reaction frequency downstream of the void and affects the detonation performance,especially the solvent co-crystals.

关键词： CL-20 co-crystals Molecular dynamics simulation Reactive forcefield Impact response Hot spot Void defect

Microstructure evolution and phase transformation of the mushy zone in a quenchedβ-solidifying TiAl alloy

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Journal of Materials Science & Technology 2024年第2期169卷 28-41页

作者： Fuqiang Zhang Xianfei Ding Leming Xu Xin feng Hai Nan Jianping He Yongfeng Liang Junpin lin State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Cast Titanium Alloy R&D Center Beijing Institute of Aeronautical MaterialsBeijing 100095China

This study investigates the phase constitutions and transformations that occur in the mushy zone and in the adjacent phase fields of a directionally solidified Ti-44Al-8Nb-1Cr alloy via quenching *** results indicate that the mushy zone consists of unmeltedβdendrites and interdendritic liquid,whose formation can be attributed to the difference in melting point aroused by local heterogeneity in ***βdendrite is composed of numerous subgrains with various *** quenching,theβdendrite transforms into Widmanstättenαvia a precipitation reaction,owing to the decreasing cooling rate caused by heat transfer from the surrounding ***,after quenching,the interdendritic liquid is transformed intoγ*** the singleβphase field and the lower part of the mushy zone,a massive transformation ofβtoγ***,in theβ+αphase field,bothβandαphases are retained to ambient *** the heating process,the transformation ofα→βgives rise to the formation ofβvariants,which affects the orientation ofβdendrites in the mushy *** growth kinematics of theα→βtransformation was elucidated,revealing the preferential growth directions of111and112forβ***,this study presents an illustration of the formation process of the mushy zone and the microstructural evolution during the heating and quenching process.

关键词： Titanium aluminides Mushy zone Quenching Electron backscattering diffraction Phase transformation

Late Mesozoic Exhumation of the Huangling Massif:Constraints on the Evolution of the Middle Yangtze River

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 250-264页

作者： SU Jianchao lin Xu LI Chang’an Jolivet MARC WU lin CHENG feng DENG Bin WU Zhonghai CHEN Xiaokang HU Chengwei School of Geography and Information Engineering China University of GeosciencesWuhan 430074China College of Civil Engineering and Architecture China Three Gorges UniversityYichangHubei 443002China Géosciences Rennes CNRS-UMR6118Univ RennesRennesFrance State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBejing 100029China Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of EducationSchool of Earth and Space SciencesPeking UniversityBeijing 100871China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation/Chengdu University of Technology Chengdu 100871China Institute of Geological Mechanics Chinese Academy of Geological ScienceBeijing 100081China

Plate subduction leads to complex exhumation processes on *** Huangling Massif lies at the northern margin of the South China *** the Huangling Massif was exhumed as a watershed of the middle reaches of the Paleo-Yangtze River during the Mesozoic remains under *** examined the exhumation history of the Huangling Massif based on six granite bedrock samples,using apatite fission track(AFT)and apatite and zircon(U-Th)/He(AHe and ZHe)*** samples yielded ages of 157–132 Ma(ZHe),119–106 Ma(AFT),and 114–72 Ma(AHe),*** modeling revealed that three phases of rapid cooling occurred during the Late Jurassic–Early Cretaceous,late Early Cretaceous,and Late *** exhumation processes led to the high topographic relief responsible for the emergence of the Huangling *** integrated of our new data with published sedimentological records suggests that the Huangling Massif might have been the watershed of the middle reaches of the Paleo-Yangtze River since the *** that time,the rivers flowed westward into the Sichuan Basin and eastward into the Jianghan *** subduction of the Pacific Plate beneath the Asian continent in the Mesozoic deeply influenced the geomorphic evolution of the South China Block.

关键词： apatite zircon (U-Th)/He fission track Huangling Massif Yangtze River

Molecular Chain Flexibility and Dielectric Loss at High-Frequency:Impact of Ester Bond Arrangement in Poly(ester imide)s

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Chinese Journal of Polymer Science 2024年第8期42卷 1122-1133页

作者： Ya-Dong Li hong Li Lu-Kun feng feng Bao Ming-Liang Wang Cai-Zhen Zhu Zhao-Hui Zheng Xiao-Bin Ding Jian Xu Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100081China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China

The evolution of high-frequency communication has accentuated the significance of controlling dielectric properties in polymer ***,it has been theorized that rigid molecular chains lead to lower dielectric ***,the validity of this proposition at high frequencies remains *** scrutinize the correlation between chain flexibility and dielectric properties,we synthesized six poly(ester imide)s(PEIs)with systematically varied molecular chain flexibilities by modifying the ester's substitution on the aromatic *** introduction of ester bonds bestowed all PEI films with a low dielectric dissipation factor(D_(f)),ranging from 0.0021 to 0.0038 at 10 GHz in dry *** dry D_(f)displayed a pattern consistent with volume polarizability(P/V).Unexpectedly,PI-mmm-T,featu ring the most flexible molecular chain,exhibited the lowest dielectric loss under both dry(0.0021@10 GHz)and hygroscopic(0.0029@10 GHz)***,the observed increase in D_(f)after humidity absorption suggests that the high dielectric loss of PEI in applications may be attributed to its hygroscopic *** simulations and characterization of the aggregation structure revealed that the smaller cavities within flexible molecular chains,after close stacking,impede the entry of water *** sacrificing high-temperature resistance,the precursor exhibited enhanced solubility properties and could be processed into high-quality *** research unveils new insights into the relationship between flexibility and highfrequency dielectric loss,offering innovative perspectives on synthesizing aromatic polymers with exceptional dielectric properties.

关键词： 5G communications Poly(ester imide)s Molecular chain flexibility Dielectric properties Humidity absorption

Low Surface Brightness Galaxies Selected by Different Model Fitting

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Research in Astronomy and Astrophysics 2024年第1期24卷 223-236页

作者： Bing-Qing Zhang hong Wu Wei Du Pin-Song Zhao Min He feng-Jie Lei Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

We present a study of low surface brightness galaxies(LSBGs) selected by fitting the images for all the galaxies inα.40 SDSS DR7 sample with two kinds of single-component models and two kinds of two-component models(disk+bulge):single exponential,single sersic,exponential+deVaucular(exp+deV),and exponential+sérsic(exp+ser).Under the criteria of the B band disk central surface brightness μ_(0,disk)(B)≥22.5 mag arcsec^(-2) and the axis ratio b/a> 0.3,we selected four none-edge-on LSBG samples from each of the models which contain 1105,1038,207,and 75 galaxies,*** are 756 galaxies in common between LSBGs selected by exponential and sersic models,corresponding to 68.42% of LSBGs selected by the exponential model and 72.83% of LSBGs selected by the sersic model,the rest of the discrepancy is due to the difference in obtaining μ_(0) between the exponential and sersic *** on the fitting,in the range of 0.5≤n≤1.5,the relation of μ_(0) from two models can be written as μ_(0,sérsic)-μ_(0,exp)=-1.34(n-1).The LSBGs selected by disk+bulge models(LSBG_(2)comps) are more massive than LSBGs selected by single-component models(LSBG_1comp),and also show a larger disk *** the bulges in the majority of our LSBG_(2)comps are not prominent,more than 60% of our LSBG_(2)comps will not be selected if we adopt a single-component model *** also identified 31 giant low surface brightness galaxies(gLSBGs) from LSBG_(2)*** are located at the same region in the color-magnitude diagram as other *** we compared different criteria of gLSBGs selection,we find that for gas-rich LSBGs,M_(*)> 10^(10)M_⊙ is the best to distinguish between gLSBGs and normal LSBGs with bulge.

关键词： catalogs galaxies:spiral galaxies:bulges methods:data analysis methods:statistical

Endoplasmic reticulum stress improved chicken tenderness,promoted apoptosis and autophagy during postmortem ageing

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Food Science and Human Wellness 2024年第4期13卷 2141-2151页

作者： Yuwei Chai lin Chen Shuya Xiang linxuan Wu Xuebo Liu Jun Luo Xianchao feng College of Food Science and Engineering Northwest A&F UniversityYangling 712100China College of Animal Science and Technology Northwest A&F UniversityYangling 712100China

In this study,endoplasmic reticulum(ER)stress inducer tunicamycin(TM)and inhibitor 4-phenylbutyric acid(4-PBA)were used to treat postmortem chicken breast muscle to investigate changes in tenderness and effects on apoptosis and autophagy during 5 days ***-induced ER stress reduced shear force,enhanced myofibril fragmentation index(MFI),disrupted myofibril structure,increased desmin degradation,and activatedμ-calpain and *** addition,TM-induced ER stress increased the expression of Bax,Bim,and cytochrome c,and decreased the expression of Bcl-x ***,TM-induced ER stress improved the conversion of LC3I to LC3II,raised the expression of Beclin-1,and decreased the expression of p62,PI3K,and m *** opposite results were observed after 4-PBA *** results suggested that ER stress could improve chicken tenderness,promote apoptosis and autophagy during chicken postmortem ageing.

关键词： Endoplasmic reticulum stress Tenderness Apoptosis Autophagy Chicken

Construction of cytomegalovirus promoter-driven gene expression system in Laodelphax striatellus

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Insect Science 2024年第3期31卷 720-732页

作者： Xiaohui Cheng Wan Zhao Guohua Liang hong Lu Yumei Fu Yiming Li feng Cui State Key Laboratory of Integrated Management of Pest Insects and Rodents Insttute of ZoologyChinese Academy of SciencesBejingChina University of Chinese Academy of Sciences BejingChina School of Life Sciences Hebei UniversityBaodingHebei China Key Laboratory of Animal Ecology and Conservation Biology Institute of ZoologyChinese Academy of SciencesBejingChina Institute of Wetland Ecology&Clone Ecologyl Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation Taizhou UniversityTaizhouZhejiangChina

The small brown planthopper(SBPH,Laodelphax striatellus)is a significant rice pest,responsible for transmitting rice stripe virus(RSV)in a persistent and propagative *** is one of the most detrimental rice viruses,causing rice stripe disease,which results in considerable loss of rice grain *** RNA interference and gene knockout techniques have enabled gene downregulation in SBPH,no system currently exists for the overexpression of endogenous or exogenous ***,the development of a protein expression system for SBPH is imperative to serve as a technical foundation for pest control and gene function *** study aimed to construct an expression vector using the promoter of the constitutive-expressed tubulin gene of SBPH,and promoter of human cytomegalovirus(CMV).Fluorescence experiments demonstrated that both tubulin and CMV promoter could drive green fluorescent protein(GFP)expression in SBPH,and could also facilitate the expression of a nucleocapsid protein(NP)-GFP fusion protein containing viral NP with comparable *** expression vector optimization,we have identified that the 3 tandem CMV promoters display a significantly higher promoter activity compared with both the 2 tandem CMV promoters and the single CMV *** addition,the incorporation of Star polycation nanoparticles significantly enhanced the expression efficiency in *** results provide a promising technical platform for investigating gene functions in SBPH.

关键词： cytomegalovirus promoter gene expression system nanoparticle small brown planthopper

Metal Ions Induced Vesicle Formation of Single-Chained Hydrocarbon Surfactants with Coordinated Headgroups

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Wuhan University Journal of Natural Sciences 2005年第6期10卷 1035-1040页

作者： GUO hong-tao XU Fei GAO Nan ZHOU Xiao-hai DONG Jin-feng hong Xin-lin ZHANG Gao-yong College of Chemistry and Molecular Sciences Wuhan University Wuhan 430072 Hubei China

The surfactant of N-dodecyliminodipropionate disodium salt has been synthesized, and structure has been well characterized. The properties in aqueous solution have been studied by potentiometric titration, surface tension, transmission electron microscopy （TEM） and uhra-violet （UV） spectra. It was found that N-dodecyliminodipropionate disodium could exist in four species （e. g. cation, zwitterion, monoanion, dianion） in aqueous solution depending on pH,and relative distribution of these ionic species as a function of pH was obtained. The critical micelle concentration （CMC）, determined from the breakpoint of surface tension at different concentrations, is 4. 16 × 10^1 mol/L, and the surface tension at CMC is 30 mN/m. It was found that the self-aggregate structures in aqueous solution transformed from micelles to vesicles after the Cu （Ⅱ） added. The experimental results showed that coordination between the iminodipropionate group and Cu（Ⅱ） resulted to vesicles formation.

关键词： surfactant micelle vesicle metal ion iminodipropionate

Hydrodynamic Characteristics of Undular Tidal Bores in the Qiantang River Based on Field Observations

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China Ocean Engineering 2024年第3期38卷 505-518页

作者： ZHANG Shu-yu PAN Cun-hong ZHANG Shen-yang LI Ruo-hua CHENG Wenlong XIE Dong-feng Zhejiang Tongji Vocational College of Science and Technology Hangzhou 311231China Zhejiang Institute of Hydraulics and Estuary Hangzhou 310020China

Understanding the undular tidal bores in the Qiantang River is essential for effective river management and *** breaking tidal bores have been studied extensively, reports on undular tidal bores in the Qiantang Riverremain limited. Furthermore, observed data on undular tidal bores fulfilling the requirements of short measurementtime intervals, and spring, medium, and neap tide coverage, and providing detailed data for the global vertical stratificationof flow velocity are quite limited. Based on field observations at Qige in the Qiantang estuary, we analyzedthe characteristics of undular tidal bores. The results showed that the flooding amplitude (a) of the first wave isalways larger than its ebbing amplitude (b). Moreover, the vertical distribution of the maximum flood velocity exhibitesthree shapes, influenced by the tidal range, while that of the maximum ebb velocity exhibites a single shape. Duringthe initial phase of the flood tide in the spring and medium tides, the upper water body experiences multiple oscillatingchanges along the flow direction, corresponding to the alternating process of the crest and trough of the tide levelupon the arrival of the tidal bore. The tidal range is a crucial parameter in tidal bore hydrodynamics. By establishingthe relationship between hydrodynamic parameters and tidal range, other hydrodynamic parameters, such as the tidalbore height, maximum flood depth–averaged velocity, maximum flood stratified velocity at the measurement points,and duration of the flood tide current, can be effectively predicted, thereby providing an important reference for rivermanagement and maintenance.

关键词： tidal bores Qiantang Estuary tidal bore height tidal bore velocity propagation speed