检索结果-南通市图书馆

Charge transfer complex enabled photoreduction of ether phosphonium salts for the selective oxyalkylation of enamides

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第2期35卷 411-414页

作者： Sen Qiao Kunquan chen qiang liu Zhixiang Wang Xiangyu chen School of Chemical Sciences University of the Chinese Academy of SciencesBeijing 100049China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou 256606China

A charge transfer complex(CTC)-enabled photoreduction of ether phosphonium salts for the generation of oxyalkyl radicals was *** photoreduction provides a convenient method to achieve selective oxyalkylation of enamid... 详细信息

关键词： Enamides Phosphonium salts Ethers Charge transfer complex Visible light

Distribution, bioaccumulation, trophic transfer and risk assessment of trace elements in fish from a typical shallow outflow lake basin, China

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第7期18卷 141-156页

作者： Miao He Guijian liu Xiaodan Shi Lei Wu qiang chen CAS Key Laboratory of Crust-Mantle Materials and Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Anhui Academy of Environmental Sciences Hefei 230022China School of Resources and Environmental Engineering Hefei University of TechnologyHefei 230009China

Fish are important food sources for humans,and the availability of appropriate amount of trace elements(TEs)plays a crucial role in fish ***,due to large volumes of sewage discharge,high levels of certain elements are present in aquatic environments,and these elements accumulate in fish and potentially affect human *** this study,the distribution and bioaccumulation capacity of trace elements in six dominant fish species from Chaohu Lake(China)were *** results showed that the bioaccumulation capacity of fish for Zn was greater than other *** the source of the TEs in the fish were explored along with the concentration of the TEs in the aquatic environment,which indicated that TEs in fish were mainly obtained through ingestion and indirectly affected by the industrial activities in the ***,stable carbon and nitrogen isotopes were used to classify the trophic levels and explore the biological magnification of TEs of the *** was found that Sb and Sr showed biomagnification with the increase of trophic level of *** on the above analyses,the environmental biogeochemical cycle model of TEs in the lake was distinguished and established,which can offer valuable insights for sustainable fishery management in the downstream Yangtze River Delta ecosystem.

关键词： Trophic level Bioaccumulation Risk assessment Trace elements

An anti-icing scaling method for wind tunnel tests of aircraft thermal ice protection system

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 Journal of Aeronautics 2024年第6期37卷 1-6页

作者： Yu liu qiang WANG Xian YI Ningli chen Jinghao REN Weihao LI Key Laboratory of Icing and Anti/de-icing China Aerodynamics Research and Development CenterMianyang 621000China State Key Laboratory of Aerodynamics Mianyang 621000China

The efficiency of the aircraft Ice Protection Systems(IPSs)needs to be verified through icing wind tunnel ***,the scaling method for testing the IPSs has not been systematically established yet,and further research is *** the present study,a scaling method specifically designed for thermal IPSs was derived from the governing equation of thin water *** scaling parameters were adopted to address the heat and mass transfer involved in the thermal anti-icing *** method validation,icing wind tunnel tests were conducted using a jet engine nacelle model equipped with a bleed air *** non-dimensional surface temperature and runback ice closely matched for both the reference and scaled *** validation confirms that the scaling method is capable of achieving the similarity of surface temperature and the runback ice *** anti-icing scaling method can serve as an important supplement to the existing icing similarity theory.

关键词： Scaling method Ice protection system Water film Anti-icing test Icing wind tunnel

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

AP assembled on ultrafine aluminum particle and its application to NEPE propellant

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第6期36卷 20-29页

作者： Huixin Wang qiang Li Hui Ren Liangjun Xie Tingting liu Zhihong chen State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Inner Mongolia Institute of Synthetic Chemicals Hohhot 010010China

Coating modification is an important way to enhance the reactivity of aluminum *** this paper,ammonium perchlorate and aluminum powder were assembled into energetic microunits by liquid deposition *** particles with AP as shell and ultrafine aluminum powder as the core(Al@AP)were *** micromorphology results show that the coated particles are about 5μm,and the coating layer is evenly distributed on the outer surface of aluminum powder,indicating a complete *** energetic microunits were implanted into the nitrate ester plasticizing adhesive system(NEPE)as solid phase *** effect of filler on the rheological properties,safety,mechanical properties,thermal reaction and energy properties of the system was analyzed by comparing with the raw aluminum *** test results show that the rheological properties,mechanical properties and pressure index of NEPE containing system Al@AP meets the requirements of solid propellant *** with Al based propellant,the mechanical sensitivity and thermal sensitivity are decreased,the safety is better,and the explosion heat of the propellant is increased by 7.8%.The engine test shows that the specific impulse is increased by 1.2 ***@AP can improve the energy output and safety of NEPE propellant,and has potential application prospects in high-energy propellants.

关键词： Aluminum powder Coating NEPE propellant Energy output Applied research

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

Purification performance on molten steel of novel Al_(2)O_(3)-based ceramic filter prepared from microporous powder and nano-Al_(2)O_(3) powder

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 Iron and Steel Research International 2024年第6期31卷 1535-1546页

作者： Zhe chen Wen Yan Ying liu Guang-qiang Li Shao-song Hong Nan Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Jiangsu Shengnai New Materials Co. Ltd.Taizhou 225534JiangsuChina

Reticulated ceramic foam filters provide an effective way to purify molten steel by removing non-metallic *** proposed a novel strategy to improve the purification performance of Al_(2)O_(3)-based ceramic filters by using microporous corundum-spinel raw materials to replace dense raw *** kinds of Al_(2)O_(3)-based ceramic filters fabricated from dense α-Al_(2)O_(3) micro-powder or microporous corundum-spinel powder were selected to carry out the immersion tests with molten *** the one hand,the higher surface roughness of the filter skeleton prepared from microporous raw materials increased the adsorption capacity of skeleton surface on inclusions in molten *** the other hand,the higher apparent porosity and larger pore size of the filter skeleton were more beneficial to the penetration of molten steel in the micropores of *** reaction process at the solid-liquid interface also improved the wettability of the interface between skeleton and molten steel,resulting in a larger penetration depth and a better adsorption effect on the *** summary,the novel Al_(2)O_(3)-based ceramic filter prepared with microporous corundum-spinel powder and addition of 5 wt.% nano-Al_(2)O_(3) powder reduced the total oxygen content of the steel from 40.2×10^(-4) to 12.7×10^(-4) wt.% by 68.4% and the Al content from 0.46 to 0.18 wt.% by 60.9% after immersion test,presenting the most excellent purification performance on molten steel.

关键词： Al_(2)O_(3)-based ceramic filter Microporous corundum-spinel powder Non-metallic inclusion-Microstructure Molten steel purification

Simulating the GRF of Humanoid Robot Vertical Jumping Using a Simplified Model with a Foot Structure for Foot Design

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 Bionic Engineering 2024年第1期21卷 112-125页

作者： Chuanku Yi Xuechao chen Yu Zhang Zhangguo Yu Haoxiang Qi Yaliang liu qiang Huang School of Mechatronical Engineering Beijing Institute of TechnologyZizhuyaunHaidianBeijing 100081China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Tec

There are many theories and tools for human or robot motion simulation,but most of them require complex *** LNZN model(a simplified model named by the proposers)simplifies the human model and facilitates simulation of the Ground Reaction Force(GRF)of body landing by spring damping model and ignoring joint rotation movements,which can reduce the amount of computation *** this paper,the LNZN model of human running is selected as the basis and is modified to obtain the LNZN model of a robot,which expands the application of the LNZN *** to the structure of the human foot,a foot structure is then added to the simplified model to reduce the *** also applied driving forces to the new model to simulate the whole high jump motion of the robot to expand the functions of the LNZN *** obtained GRF data were anastomotic to the actual experimental *** addition,the effects of variables,such as the mass,hardness,and damping,of the foot on the GRF at the moment of landing were also ***,based on the guidelines obtained for the design of the robot’s foot structure,we fabricated new robot’s feet and installed them on the actual robot and achieved a better cushioning effect than the original foot in experiments.

关键词： LNZN model-GRF simulation Humanoid foot structure Foot parameters

Perception-Driven Learning of High-Dynamic Jumping Motions for Single-Legged Robots

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 Bionic Engineering 2024年第4期21卷 1733-1746页

作者： Nengxiang Sun Fei Meng Sai Gu Botao liu Xuechao chen Zhangguo Yu qiang Huang School of Mechatronical Engineering Beijing Institute of TechnologyBeijing100081China Key Laboratory of Biomimetic Robots and Systems Ministry of EducationBeijing100081China

Legged robots show great potential for high-dynamic motions in continuous interaction with the physical environment,yet achieving animal-like agility remains significant *** animals usually predict and plan their next locomotion by combining high-dimensional information from proprioception and exteroception,and adjust the stiffness of the body’s skeletal muscle system to adapt to the current *** control methods have limitations in handling high-dimensional state information or complex robot motion that are difficult to plan manually,and Deep Reinforcement Learning(DRL)algorithms provide new solutions to robot motioncontrol *** by biomimetics theory,we propose a perception-driven high-dynamic jump adaptive learning algorithm by combining DRL algorithms with Virtual Model Control(VMC)*** robot will be fully trained in simulation to explore its motion potential by learning the factors related to continuous jumping while knowing its real-time jumping *** policy trained in simulation is successfully deployed on the bio-inspired single-legged robot testing platform without further *** results show that the robot can achieve continuous and ideal vertical jumping motion through simple training.

关键词： Deep reinforcement learning High-dynamic jump Perception driven Single-legged robot