检索结果-南通市图书馆

New triterpenoid sapoin from Ardisia gigantifolia Stapf.

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2010年第4期21卷 449-452页

作者： gong, qiang qiang Mu, Li Hua Liu, Ping Yang, Shi Lin Wang, Bo Feng, Yu Lin Gen Hosp PLA Dept Clin Pharmacol Beijing 100853 Peoples R China JiangXi Univ Tradit Chinese Med Nanchang 330006 Peoples R China

One new triterpenoid sapoin with two known triterpenoid sapoins:3β-O-{α-L-rhamnopyranosyl-(1→3)-[β-D-xylopyranose-(1→2)]-β-D-glucopyranosyl-(1→4)-α-L-arabinopyranosyl}-3β-hydroxy-13β,28-epoxy-oleanan-16-oxo-30-al(1),3β-O-{α-L-rhamnopyranosyl-(1→3)-[(β-D-xylopyranosyl-(1→2)]-β-D-galactopyranosyl-(1→4)-[(β-D-glucopyranosyl-(1→2)]-α-L-ara-binopyranoside}-16α-hydroxy-13,28-epoxy-oleanane(2) and cyclamiretin A 3β-O-α-L-rhamnopyranosyl-(l→3)-[P-D-xylopyranosyl-(1→2)]-β-D-glucopyranosyl-(1→4)-[β-D-glucopyranosyl-(...

关键词： Ardisia gigantifolia Stapf. Myrsinaceae Triterpenoid sapoin

Emergent symmetry in quantum phase transition:From deconfined quantum critical point to gapless quantum spin liquid

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2024年第2期69卷 190-196页

作者： Wen-Yuan Liu Shou-Shu gong Wei-qiang Chen Zheng-Cheng Gu Department of Physics The Chinese University of Hong KongHong KongChina Division of Chemistry and Chemical Engineering California Institute of TechnologyPasadena CA 91125USA School of Physical Sciences Great Bay UniversityDongguan 523000China Great Bay Institute for Advanced Study Dongguan 523000China Department of Physics and Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

The emergence of exotic quantum phenomena in frustrated magnets is rapidly driving the development of quantum many-body physics,raising fundamental questions on the nature of quantum phase *** we unveil the behaviour of emergent symmetry involving two extraordinarily representative phenomena,i.e.,the deconfined quantum critical point(DQCP)and the quantum spin liquid(QSL)*** large-scale tensor network simulations,we study a spatially anisotropic spin-1/2 square-lattice frustrated antiferromagnetic(AFM)model,namely the J1x-J1y-J2 model,which contains anisotropic nearestneighbor couplings J1x,J1y and the next nearest neighbor coupling *** small J1y/J1x,by tuning J2,a direct continuous transition between the AFM and valence bond solid phase is *** growing J1y/J1x,a gapless QSL phase gradually emerges between the AFM and VBS *** observe an emergent O(4)symmetry along the AFM–VBS transition line,which is consistent with the prediction of DQCP *** surprisingly,we find that such an emergent O(4)symmetry holds for the whole QSL–VBS transition line as *** findings reveal the intrinsic relationship between the QSL and DQCP from categorical symmetry point of view,and strongly constrain the quantum field theory description of the QSL *** phase diagram and critical exponents presented in this paper are of direct relevance to future experiments on frustrated magnets and cold atom systems.

关键词： Tensor network Quantum phase transition Emergent symmetry Quantum spin liquid Deconfined quantum critical point Anisotropic

Relative orbit determination algorithm of space targets with passive observation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第3期35卷 793-804页

作者： DAI Chenchao qiang Hongfu ZHANG Degang HU Shaolei gong Baichun Zhijian Laboratory Rocket Force University of EngineeringXi’an 710025China College of Astronautics Nanjing University of Aeronautics and AstronauticsNanjing 210016China China Flight Test Research Institute Xi’an 710089China Beijing Institute of Control and Electronic Technology Beijing 100038China

Angles-only relative orbit determination for space non-cooperative targets based on passive sensor is subject to weakly observable problem of the relative state between two spacecraft. Previously, the evidence for angles-only observability was found by using cylindrical dynamics, however, the solution of orbit determination is still not provided. This study develops a relative orbit determination algorithm with the cylindrical dynamics based on differential evolution. Firstly, the relative motion dynamics and line-of-sight measurement model for nearcircular orbit are established in cylindrical coordinate ***, the observability is qualitatively analyzed by using the dynamics and measurement model where the unobservable geometry is found. Then, the angles-only relative orbit determination problem is modeled into an optimal searching frame and an improved differential evolution algorithm is introduced to solve the problem. Finally, the proposed algorithm is verified and tested by a set of numerical simulations in the context of highEarth and low-Earth cases. The results show that initial relative orbit determination(IROD) solution with an appropriate accuracy in a relative short span is achieved, which can be used to initialize the navigation filter.

关键词： angles-only measurement relative orbit determination cylindrical coordinate differential evolution

Recycling of spent lithium-ion batteries to resynthesize high-performance cathode materials for sodium-ion storage

在线全文

学校读者我要写书评

暂无评论

Tungsten 2024年第3期6卷 574-584页

作者： Hai-qiang gong Xing-Yuan Wang Long Ye Bao Zhang Xing Ou National Engineering Laboratory for High-Efficiency Recovery of Refractory Nonferrous Metals School of Metallurgy and Environment Central South University

The spent lithium-ion batteries recovery has been brought into focus widely for its environmental imperatives and potential profits from the metal components,such as lithium,cobalt,nickel and ***,the weaker pollution and fewer profits of LiMn2O4cathode dispel the enthusiasm and responsibility of industry ***,a simplified and efncient method to regenerate the sodium-ion cathode materials and separate Li from spent LiMn2O4materials for the profit improvement is *** detail,adjusting the parameters of carbothermal reduction process appropriately,the LiMn2O4spinel structure is destroyed within a short period time and transformed into simple metal *** anticipated,nearly 95 wt.%lithium can be obtained and recovered during the water leaching,while 99 wt.% of manganese can be extracted in acid *** that the leaching residue can return to the carbothermic reduction,leading to a closed-loop economic recycling *** regenerated Na0.67Ni0.3Mn0.7O2cathode displays excellent electrochemical performance with superior cycling stability(the initial capacity reaches 95.9 mAh·g-1,and the retention rate reached 98.3% after 100 cycles at 1 C).The delicate strategy of sodium-ion cathode material regenerated from spent LiMn2O4aims to realize lithium separation and material utilization of manganese simultaneously,providing the instructive suggestion to rise up the recycling profits of spent batteries.

关键词： Manganese Spent battery LiMn 2 O 4 cathode Recycling Regenerated Na 0.67 Ni 0.3 Mn 0.7 O 2 Sodium-ion storage

Data-driven mapping-relationship mining between hardness and mechanical properties of dual-phase titanium alloys via random forest and statistical analysis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第2期43卷 829-841页

作者： Hai-Chao gong Qun-Bo Fan Hong-Mei Zhang Xing-Wang Cheng Wen-qiang Xie Kai Chen Lin Yang Jun-Jie Zhang Bing-qiang Wei Shun Xu School of Materials Science and Engineering Beijing Institute of TechnologyBeijing100081China National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing401135China Department of Mechanical and Materials Engineering University of Nebraska-LincolnLincolnNE68588USA

In order to accelerate the research on the property optimization of titanium alloy based on high-throughput methods,it is necessary to reveal the relationship between hardness and other mechanical properties which is still *** this work,taking Ti20C alloy as research object,almost all the microstructure of dual-phase titanium alloys were covered by traversing over 100 heat treatment ***,massive experiments including microstructure characterization and performance test were conducted,obtaining 51,590 pieces of microstructure data and 3591 pieces of mechanical property ***,based on large-scale data-driven technology,the quantitative mapping relationship between hardness and other mechanical properties was deeply *** results of random forest models showed that the correlation between hardness(H)and Charpy impact energy(A_(k))(or elongation,A)was hardly dependent on the microstructure types,while the relationship between H and tensile strength(R_(m))(or yield strength,R_(p0.2))was highly dependent on microstructure ***,combined with statistical analysis,it was found that the relationship between H and Ak(or A)were negatively ***,the relationship between H and strength was positively linear for equiaxed microstructure,and strength was linked to d^(−1/2)(d,equivalent circle diameter)ofα-grains in the form of classical Hall–Petch formula;but for other microstructures,the relationships were ***,the above rules were nearly the same in the rolling direction and transverse ***,a"four-quadrant partition map"between H and R_(p0.2)/R_(m) was established as a versatile material-screening tool,which can provide guidance for on-demand selection of titanium alloys.

关键词： Dual-phase titanium alloy Data-driven Hardness Mapping relationship

∼2.5 nm pores in carbon-based cathode promise better zinc-iodine batteries

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第5期35卷 471-476页

作者： Yajun Hou Chuanzheng Zhu qiang Wang Xiaomeng Zhao Kun Luo Zongshuai gong Zhihao Yuan School of Materials Science and Engineering Tianjin Key Laboratory of Photoelectric Materials&DevicesTianjin University of TechnologyTianjin 300384China

The relationship mechanism between the material pore structures and cathodic iodine chemistry plays a vital role in efficient Zn-I_(2) batteries,but is unclear,retarding further *** work innovatively indicates a great contribution of∼2.5nm pore structure of nanocarbons to efficient iodine adsorption,rapid I^(−)↔I_(2) conversion,and polyiodide inhibition,via scrupulously designing catalysts with controllable pore sizes *** I_(2)-loading within the designed nitrogen-doped nanocarbons can reach up to as high as 60.8 wt%.The batteries based on the cathode deliver impressive performances with a large capacity of 178.8 mAh/g and long-term cycling stability more than 4000 h at 5.0 ***,these is no polyiodide such as I_(3)−and I_(5)−detected during the charge-discharge processes from comprehensive electrochemical cyclic voltammetry,X-ray photoelectron spectroscopy,and Raman *** work provides a novel knowledge-guided concept for rational pore design,promising better Zn-I_(2) batteries,which is also hoped to benefit other advanced energy technologies,such as Li-S,Li-ion,and Al-I_(2) batteries.

关键词： Zinc-iodine batteries Structure-performance relationship Iodine conversion chemistry Cathode materials Porous carbon

Effects of projectile parameters on the momentum transfer and projectile melting during hypervelocity impact

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第2期32卷 89-103页

作者： Wenjin Liu Qingming Zhang Renrong Long Zizheng gong Ren Jiankang Xin Hu Siyuan Ren qiang Wu Guangming Song State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Beijing Institute of Spacecraft Environment Engineering China Academy of Space TechnologyBeijing100094China

The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical *** comparing the computation results with the experimental results,the correctness of the calculation and the statistical method of momentum transfer coefficient is *** shapes of aluminum,copper and heavy tungsten alloy projectiles striking aluminum,basalt,and pumice target for impacts up to 10 km/s are *** influence mechanism of the shape of the projectile and projectile/target density on the momentum transfer was *** an increase in projectile density and length-diameter ratio,the energy transfer time between the projectile and targets is *** projectile decelerates slowly,resulting in a larger cratering *** energy consumed by the projectile in the excavation stage increased,resulting in lower mass-velocity of ejecta and momentum transfer *** numerical simulation results demonstrated that for different projectile/target combinations,the higher the wave impedance of the projectile,the higher the initial phase transition velocity and the smaller the mass of phase *** results can provide theoretical guidance for kinetic impactor design and material selection.

关键词： Hypervelocity impact Energy partitioning Impact melting Momentum transfer

Mechanical behaviors of backfill-rock composites: Physical shear test and back-analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 807-827页

作者： Jie Xin Quan Jiang Fengqiang gong Lang Liu Chang Liu qiang Liu Yao Yang Pengfei Chen State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China School of Civil Engineering Southeast UniversityNanjing211189China Energy School Xi’an University of Science and TechnologyXi’an710054China

The shear behavior of backfill-rock composites is crucial for mine safety and the management of surface *** exposing the shear failure mechanism of backfill-rock composites,we conducted shear tests on backfill-rock composites under three constant normal loads,compared with the unfilled *** investigate the macro-and meso-failure characteristics of the samples in the shear tests,the cracking behavior of samples was recorded by a high-speed camera and acoustic emission *** parallel with the experimental test,the numerical models of backfill-rock composites and unfilled rock were established using the discrete element method to analyze the continuous-discontinuous shearing *** on the damage mechanics and statistics,a novel shear constitutive model was proposed to describe mechanical *** results show that backfill-rock composites had a special bimodal phenomenon of shearing load-deformation curve,*** first shearing peak corresponded to rock break and the second shearing peak induced by the broken of aeolian sand-cement/fly ash paste ***,the shearing characteristic curves of the backfill-rock composites could be roughly divided into four stages,*** shear failure of the specimens experienced:stage I:stress concentration;stage II:crack propagation;stage III:crack coalescence;stage IV:shearing *** numerical simulation shows that the existence of aeolian sand-cement/fly ash paste backfill inevitably altered the coalescence type and failure mode of the specimens and had a strengthening effect on the shear strength of backfillrock *** on damage mechanics and statistics,a shear constitutive model was proposed to describe the shear fracture characteristics of specimens,especially the bimodal ***,the micro-and meso-mechanisms of shear failure were discussed by combining the micro-test and numerical *** research can advance the better understanding of the shear behavior of

关键词： Physical simulation Backfill-rock composites Shear failure Cracking Shear constitutive model

Oxidation behavior of 4774DD1 Ni-based single-crystal superalloy at 980℃ in air

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2024年第2期21卷 116-124页

作者： Yu Fang Ya-zhou Li qiang Yang Qun-gong He Xiu-fang gong Qian Duan Hai-yang Song Fu Wang Qiong-yuan Zhang Hong Zeng State Key Laboratory of Long-Life High Temperature Materials Dongfang Turbine Co.Ltd.Deyang 618000SichuanChina State Key Laboratory for Manufacturing System Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China

The oxidation behavior of a novel Ni-based single-crystal 4774DD1 superalloy for industrial gas turbine applications was investigated by the isothermal oxidation at 980℃ and discontinuous oxidation weight gain *** phase constitution and morphology of surface oxides and the characteristics of the crosssection oxide film were analyzed by XRD,SEM and *** show that the oxidation kinetics of the 4774DD1 superalloy follows the cubic law,indicating its weak oxidation resistance at this *** the oxidation time increases,the composition of the oxide film evolves as following:One layer consisting of a bottom Al_(2)O_(3)sublayer and an upper(Al_(2)O_(3)+NiO)mixture sublayer after oxidized for 25 ***,two layers composed of an outermost small NiO discontinuous grain layer and an internal layer for 75 *** internal layer is consisted of the bottom Al_(2)O_(3)sublayer,an intermediate narrow CrTaO_(4)sublayer,and an upper(Al_(2)O_(3)+NiO)mixture *** two layers comprising an outermost relative continuous NiO layer with large grain size and an internal layer as the oxidation time increases to 125 *** internal layer is composed of the upper(Al_(2)O_(3)+NiO)mixture sublayer,an intermediate continuous(CrTaO_(4)+NiWO_(4))mixture sublayer,and a bottom Al_(2)O_(3)***,three layers consisting of an outermost(NiAl2O_(4)+NiCr2O_(4))mixture layer,an intermediate(CrTaO_(4)+NiWO_(4))mixture layer,and a bottom Al_(2)O_(3)layer for 200 h.

关键词： nickel-base single crystal superalloy oxidation kinetics oxide film microstructure mechanism