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Space truss construction modeling based on on-orbit assembly motion feature

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Chinese Journal of Aeronautics 2024年第3期37卷 365-379页

作者： Changjie ZHAO Weizhong GUO meng chen Jiaxing HU Youcheng HAN Rongfu LIN State Key Lab of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Institute of Aerospace System Engineering Shanghai Shanghai 201109China

More space truss construction has been planned to develop and utilize space *** trusses are designed in the way of large-scale,complex,modular,and on-orbit *** meet the upcoming challenge of large-scale space infrastructure construction,it is necessary to study space truss automation design and robotic *** paper proposes an ordinal finite screw adjacency matrix model(OFSAMM),focusing on the relationship between assembly motions,to express and compute a space truss *** this model,a space truss is abstracted as a set of ordered assembly motions,each of which is recorded as a finite screw as the basic element of the truss and its *** operation of truss transformation is also derived under this ***,the truss configuration,the assembly sequence,the truss sub-assembly,the truss components,and the on-orbit assembly task can be expressed and calculated in a unified model,which is calculated and stores the truss topology and assembly with the minimum storage *** the end of this paper,we introduce how to synthesize and optimize space truss design through two *** study will help to improve design ***,it provides a theoretical basis for the automatic construction of space truss structures,especially in the next stage.

关键词： Adjacency matrix Finite screw On-orbit construction modeling Space applications Space trusses Topology design

Azocalixarenes: a scaffold of universal excipients with high efficiency

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Science China Chemistry 2024年第5期67卷 1697-1706页

作者： Yu-Xin Yue Yi-Lin Lin meng-meng chen Han-Wen Tian Rong Ma Ze-Han Wang Fang-Yuan chen Yu-chen Pan Dong-Sheng Guo College of Chemistry State Key Laboratory of Elemento-Organic ChemistryKey Laboratory of Functional Polymer Materials(Ministry of Education)Frontiers Science Center for New Organic MatterCollaborative Innovation Center of Chemical Science and Engineering(Tianjin)Nankai UniversityTianjin 300071China

Excipients are important components of pharmaceutical preparations that affect their quality, safety, and efficacy. Macrocyclic receptors are a family of supramolecular excipients with several advantages, including molecular-level protection, small sizes,fast kinetics of host-guest recognition, and modular construction. With the continuous advances in the medical field, personalized and precision medicine requires the development of excipients with low dosages, integrated modifying effects, universality,and controlled release. To meet these requirements, we have developed a new family of macrocyclic excipients based on calixarenes by integrating their covalent(broad chemical design space) and noncovalent(wide range of substrates) ***, azocalixarenes(Azo CAs) were designed, showing high binding affinities to a broad spectrum of active pharmaceutical ingredients(APIs), selectivity to interferents, and responsiveness to hypoxic microenvironments. Due to their highly efficient and controllable recognition, Azo CAs serve as low-dose excipients for 30 APIs. Molecular encapsulation by Azo CAs results in the integrated modification of the physicochemical properties of APIs, including solubility, stability, bioavailability,and biocompatibility. Moreover, Azo CAs can be reduced by azoreductases overexpressed in hypoxic microenvironments,leading to the controlled release of APIs. Collectively, Azo CA excipients have broad application prospects for a series of diseases such as enteritis, arthritis, stroke, cancer, bacterial infection and kidney injury, with diverse therapeutic modalities,including chemotherapy, photodynamic therapy, photothermal therapy, immunotherapy, boron neutron capture therapy, radiotherapy, fluorescence imaging, and their combinations.

关键词： supramolecular chemistry host-guest systems excipient calixarene molecular recognition

Optimizing FeCoNiCrTi high-entropy alloy with hydrogen pumping effect to boost de/hydrogenation performance of magnesium hydride

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Rare Metals 2024年第7期43卷 3273-3285页

作者： meng-chen Song Fu-Ying Wu Yi-Qun Jiang Xiu-Zhen Wang Hu Zhao Li-Xin chen Liu-Ting Zhang School of Energy and Power Instrumental Analysis CenterJiangsu University of Science and Technology Max Planck Institute for Iron Research School of Mechanical and Aerospace Engineering Nanyang Technological University State Key Laboratory of Silicon Materials Department of Materials Science and EngineeringZhejiang University

The exploration of efficient,long-lived and cost-effective transition metal catalysts is highly desirable for the practical hydrogen storage of magnesium hydride（MgH2） in sustainable energy ***,FeCoNiCrTi high-entropy alloy（HEA） nanosheets were prepared via a facile wet chemical ball milling strategy and they were introduced into MgH2to boost the hydrogen storage *** refined HEA exhibited superior catalytic activity on *** contrast to additive-free MgH2,the initial desorption temperature of the constructed MgH2-HEA composite was reduced from 330.0 to 198.5℃ and a remarkable 51% reduction in the dehydrogenation activation energy was ***,the MgH2-HEA composite only required one-twentieth time of that consumed by pure MgH2to absorb 5.0 wt% of H2at 225℃.The synergy between the "hydrogen pumping" effect of Mg2Ni/Mg2NiH4and Mg2Co/Mg2CoH5couples,as well as the good dispersion of Fe,Cr and Ti on the surface of MgH2contributed to the enhanced de/hydrogenation performance of the MgH2-HEA *** study furnishes important steering for the design and fabrication of multiple transition metal catalysts and may push the commercial application of magnesium-based hydrides one step forward.

关键词： Hydrogen storage Magnesium hydride High-entropy alloys Catalysis

On the Bicanonical Map of Algebraic Threefolds of General Type

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Acta Mathematica Sinica,English Series 2024年

作者： meng chen chen JIANG Jian Shi YAN School of Mathematical Sciences & Shanghai Center for Mathematical Sciences Fudan University Shanghai Center for Mathematical Sciences & School of Mathematical Sciences Fudan University Department of Mathematics Northeastern University

We answer an open problem of the first author and Zhang(see Open Problem 6.4(3) in Math. Z. 258(2008), 565–585) and prove that, for any nonsingular projective 3-fold of general type with the geometric genus greater t...

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New insights into the effect of hard carbons microstructure on the diffusion of sodium ions into closed pores

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Chinese Chemical Letters 2024年第6期35卷 155-160页

作者： Mingxin Song Lijing Xie Fangyuan Su Zonglin Yi Quangui Guo cheng-meng chen CAS Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China University of Chinese Academy of Sciences Beijing 100049China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Closed pores formed in hard carbons play an essential role in sodium storage at plateau ***,the effect of different structural features on the diffusion of sodium ions into closed pores remains ***,a precursor reconstruction strategy is conducted to regulate carbon microstructures including interlayer spacing,defect concentration,and closed pore volume by changing the ratio of aromatic and polysaccharide *** structure parts tend to develop disordered carbons with fewer defects,larger interlayer spacing,and smaller closed pore volume,while polysaccharide components prefer to form disordered carbons with more defects,smaller interlayer spacing,and larger closed pore *** the correlation analysis of microstructure features and the sodium storage capacity below 0.1 *** finds that the intercalation capacity is proportional to the ratio of pseudo-graphitic domains,whereas the pore filling capacity appeared at lower potential gradually decreases with the increasing defect concentration due to homo-ionic repulsion effect,without linear correlation with shortrange microcrystalline and closed pore *** optimized sample with suitable interlayer spacing and defect concentration exhibits a high plateau capacity of 241.7 m Ah/*** work provides insights into the exploitation of closed pore sodium storage performance.

关键词： Precursor reconstruction Hard carbons Structural features Closed pore filling Sodium-ion batteries

Selective synthesis of the B_(11)H_(14)^(-) and B_(12)H_(12)^(2-) borane derivatives and the general mechanisms of the B-H bond condensation

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Science China Chemistry 2024年第3期67卷 876-881页

作者： Yi Jing Xinghua Wang Hui Han Xin-Ran Liu Xing-Chao Yu Xi-meng chen Donghui Wei Lai-Sheng Wang Xuenian chen College of Chemistry Green Catalysis CenterZhengzhou UniversityZhengzhou 450001China School of Chemistry and Chemical Engineering Henan Key Laboratory of Boron Chemistry and Advanced Energy MaterialsHenan Normal UniversityXinxiang 453007China Department of Chemistry Brown UniversityProvidenceRI 02912USA

Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties,and great efforts have been made in the past decades to find more effective synthetic ***,the established synthetic methods suffer from low efficiency and low selectivity because the mechanism of the B-H bond condensation reaction,critical for the synthesis of the polyhedral boranes,is not well *** we report highly selective and efficient synthetic methods of the salts of the tetradecahydridoundecaborate(1-)(B_(11)H^(-)_(14)) and dodecahydrido-dodecaborates(2-)(B_(12)H_(12)^(2-)) anions by employing commercially available and inexpensive starting *** theoretical and experimental investigations are carried out to elucidate the reaction *** have found that the nature of the B-H bond condensation is the dihydrogen bonding interaction in which the positively charged hydrogens(bridged hydrogens) play a crucial *** current study has not only led to more effective and selective synthetic methods for B_(11)H^(-)_(14) and B_(12)H_(12)^(2-) but also unveiled the nature of the B-H bond condensation and the general formation mechanisms of polyhedral *** finding will facilitate the development of more effective synthetic methods for polyhedral boranes and spur their wide application.

关键词： Boranes polyhedral boranes dihydrogen bond nucleophilicity

Studies of an event-building algorithm of the readout system for the twin TPCs in HFRS

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Nuclear Science and Techniques 2024年第4期35卷 82-95页

作者： Jing Tian Zhi-Peng Sun Song-Bo Chang Yi Qian Hong-Yun Zhao Zheng-Guo Hu Xi-meng chen Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of LanzhouLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Advanced Energy Science and Technology Guangdong LaboratoryHuizhou 516000China

The High-energy Fragment Separator(HFRS),which is currently under construction,is a leading international radioactive beam *** sets of position-sensitive twin time projection chamber(TPC)detectors are distributed on HFRS for particle identification and beam *** twin TPCs'readout electronics system operates in a trigger-less mode due to its high counting rate,leading to a challenge of handling large amounts of *** address this problem,we introduced an event-building *** algorithm employs a hierarchical processing strategy to compress data during transmission and *** addition,it reconstructs twin TPCs'events online and stores only the reconstructed particle information,which significantly reduces the burden on data transmission and storage *** studies demonstrated that the algorithm accurately matches twin TPCs'events and reduces more than 98%of the data volume at a counting rate of 500 kHz/channel.

关键词： High counting rate Twin TPCs Trigger-less Readout electronics Event building Hierarchical data processing

Exponential-Poisson Parameters Estimation in Moving Extremes Ranked Set Sampling Design

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Acta Mathematicae Applicatae Sinica 2024年

作者： meng chen Wang-xue chen Rui YANG Ya-wen ZHOU Department of Mathematics and Statistics Jishou University

In this article, the maximum likelihood estimators (MLEs) of the scale and shape parameters βandλfrom the Exponential-Poisson distribution will be considered in moving extremes ranked set sampling(MERSS). These MLEs will be compared in terms of asymptotic efficiencies. The numerical results show that these MLEs in MERSS can be real competitors against those in simple random sampling.

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基于Z变换和改进FRI的LFM信号参数估计方法研究

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系统工程与电子技术 2024年第7期46卷 2228-2236页

作者：孟硕孟晨王成陆军工程大学石家庄校区河北石家庄050003

为了完成线性调频(linear frequency modulation,LFM)信号的稀疏采样,并利用稀疏数据对原始信号参数进行估计,本文提出了一种基于Z变换和改进有限新息率(finite rate of innovation,FRI)的LFM信号参数估计方法。以Z变换理论为基础,设计... 详细信息

为了完成线性调频(linear frequency modulation,LFM)信号的稀疏采样,并利用稀疏数据对原始信号参数进行估计,本文提出了一种基于Z变换和改进有限新息率(finite rate of innovation,FRI)的LFM信号参数估计方法。以Z变换理论为基础,设计了一种数学模型,一旦信号能够表达成该数学模型的结构形式,就能通过Z变换和零化滤波器的方法估计信号参数。然后,利用了自相关延迟的FRI结构对LFM信号采样,该结构不仅完成了LFM信号的稀疏采样,而且稀疏采样结果能够与数学模型结构相符。在理论上通过数学论证的方式证明了所提方法能够用于获取LFM信号参数信息,并通过仿真和实测数据验证了所提方法的有效性,理论和实验结果表明该方法只需要4个采样点就能实现对LFM信号的参数估计,并且实验中的参数估计误差均在3%以内,极大的提高有限新息率采样的参数估计效率。

关键词：线性调频信号有限新息率零化滤波器 Z变换参数估计

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