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新能源接入对区域系统频率稳定的影响及机组改进控制策略

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电力科学与技术学报 2024年第2期39卷 28-34页

作者：程林王吉利韩志勇柯贤波艾东平李文锋国家电网有限公司西北分部西安陕西710049 中国电力科学研究院有限公司北京100192

针对新能源接入比迅速增大,导致区域电网频率稳定性问题日益突出这一问题,研究接入比与频率稳定性的关系,并提出水电、火电主导调频的改进控制策略。分析发现,随着接入比的增大,区域电网的等值惯量变小,等值功-频调节能力降低,导致水电... 详细信息

针对新能源接入比迅速增大,导致区域电网频率稳定性问题日益突出这一问题,研究接入比与频率稳定性的关系,并提出水电、火电主导调频的改进控制策略。分析发现,随着接入比的增大,区域电网的等值惯量变小,等值功-频调节能力降低,导致水电主导区域电网的静态、动态和暂态频率稳定性都降低,以及火电主导区域电网的静态、暂态频率稳定性降低,而动态频率稳定性基本不变。通过减小调差系数,在频率反馈通道附加微分环节,改善水电主导调频的全过程频率稳定性;在频率反馈通道附加比例微分环节,改善火电主导调频的全过程频率稳定性。仿真结果表明,影响原因分析合理,改进控制策略有效,对改善大比例新能源接入系统的频率稳定性具有重要参考价值。

关键词：新能源接入比区域系统频率稳定功—频调节控制策略

Coupling effect on the thermal hazard assessment of hazardous chemical materials via calorimetric technologies and simulation approaches

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Defence Technology（防务技术） 2024年第2期32卷 644-654页

作者： Yabei Xu Jiankun Shao Wei Wang Shengliang Xu dongping Chen State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyXiangyang 441003China

The coupling effect of heat absorption and release exists in the thermal decomposition of a few chemical ***,the impact of the above coupling on thermal hazard assessment is not considered in the literature *** this work,nitroguanidine(NQ)and 1,3,5-trinitro-1,3,5-triazine(RDX)are selected as representative materials to explore the influence of the coupling effect on the thermal hazard assessment of chemical *** linear heating experiments of NQ and RDX are carried out by a microcalorimeter and synchronous thermal *** thermal decomposition curves are decoupled by advanced thermokinetics *** thermal decomposition and kinetic parameters before and after decoupling are *** results of TG experiment show that both NQ and RDX began to lose mass during the endothermic *** endothermic melting and exothermic decomposition of NQ and RDX are coupled within this *** coupling effect has different degrees of influence on its initial decomposition temperature and safety *** with the parameters in the coupling state,the initial decomposition temperature and adiabatic induction period after decoupling *** self-accelerating decomposition temperature increases,and internal thermal runaway time *** the thermal hazard assessment of chemical materials with coupling effects,the calculated parameters after decoupling should be taken as an important safety index。

关键词： Calorimetric technologies Kinetics Thermal hazard Phase transformation Thermal decomposition

Analytical libration control law for electrodynamic tether system with current constraint

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Astrodynamics 2024年第2期8卷 237-246页

作者： Shidong Xu Ti Chen Hao Wen dongping Jin State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China

This study focuses on stabilizing the libration dynamics of an electrodynamic tether system(EDTS)using generalized torques induced by the Lorentz *** contrast to existing numerical optimization methods,a novel analytical feedback control law is developed to stabilize the in-plane and out-of-plane motions of a tether by modulating the electric current *** saturation constraint on the current is accounted for by adding an auxiliary dynamic system to the *** enhance the robustness of the proposed controller,multiple perturbations of the orbital dynamics,modeling uncertainties,and external disturbances are approximated using a neural network in which the weighting matrix and approximation error are estimated simultaneously,such that these perturbations are well compensated for during the control design of the ***,a dynamically scaled generalized inverse is utilized to address the singular matrix in the control *** closed-loop system is proven to be ultimately bounded based on Lyapunov stability ***,numerical simulations are performed to demonstrate the effectiveness of the proposed analytical control law.

关键词： electrodynamic tether system(EDTS) libration dynamics analytical control current constraint

Web Layout Design of Large Cavity Structures Based on Topology Optimization

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2665-2689页

作者： Xiaoqiao Yang Jialiang Sun dongping Jin State Key Laboratory ofMechanics and Control for Aerospace Structures College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing210016China

Large cavity structures are widely employed in aerospace engineering, such as thin-walled cylinders, blades andwings. Enhancing performance of aerial vehicles while reducing manufacturing costs and fuel consumptionhas become a focal point for contemporary researchers. Therefore, this paper aims to investigate the topologyoptimization of large cavity structures as a means to enhance their performance, safety, and efficiency. By usingthe variable density method, lightweight design is achieved without compromising structural strength. Theoptimization model considers both concentrated and distributed loads, and utilizes techniques like sensitivityfiltering and projection to obtain a robust optimized configuration. The mechanical properties are checked bycomparing the stress distribution and displacement of the unoptimized and optimized structures under the sameload. The results confirm that the optimized structures exhibit improved mechanical properties, thus offering keyinsights for engineering lightweight, high-strength large cavity structures.

关键词： Topology optimization lightweight design web layout design cavity structure

Heterobimetallic lanthanide tetrahedral cages:Synthesis,design and application for potential multimodal imaging contrast agent

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Journal of Rare Earths 2024年第2期42卷 278-285,I0002页

作者： Yongxiu Li Feng Guo Siwei Wei Duofu Li Jun Zhang Kai Xu dongping Li Department of Chemistry Nanchang UniversityNanchang330031China Key Laboratory of Functional Molecule Design and Interface Process Anhui Jianzhu UniversityHefei230601China Department of Otolaryngology Head and Neck SurgeryThe Second Affiliated Hospital of Nanchang UniversityNanchang330006China

The construction and functionalization of lanthanide-organic cages have been a research hotspot in coordination *** from the unique luminescent and magnetic properties of lanthanide ions,the potential applications of lanthanide-organic cages in biological imaging applications are promising,but only a few corresponding explorations have been *** rein,we introduced a series of lanthanide tetrahedral cages,(Eu_(n)Gd_(4-n)L_(4))(sol)_8(n=0,1,2,3 and 4,where L=(4,4',4"-tris(4,4,4-trifluoro-1,3-dioxobutyl)-triphenylamine,and sol=dimethyl sulfoxide and methanol),with potential applications in biological *** the good luminescent and magnetic properties of Eu^(3+) and Gd^(3+) ions,Eu_(4)L_(4) and Gd_(4)L_(4) complexes show a high luminescence quantum yield of 29% in DMSO and large longitudinal relaxivity(r_(1)) of 11.4(mmol/L)^(-1)/s at 0.5 T in water containing 1 vol% DMSO,*** heterobimetallic Eu-Gd complexes achieve a dual imaging mode by combining luminescent and magnetic centers in one *** the Gd:Eu ratio increases from 1:3 to 3:1,the r_(1) values increases from 5.33 to 8.64(mmoI/L)^(-1)/s,higher than that of commercial contrast agent Gd-DOTA(3.23(mmol/L)^(-1)/s).Owing to their low toxicity and good cell imaging ability toward ECA 109 cells,the selfassembled Eu-Gd heterobimetallic tetrahedral cages could be potential candidates for the multimodal imaging contrast agent.

关键词： Lanthanide organic cage Luminescence Cell imaging Contrast agents Rare earths

3D-structured carbon nanotube fibers as ultra-robust fabrics for adaptive electromagnetic shielding

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Nano Research 2024年第9期17卷 8521-8530页

作者： dongping Li Ping Wang Yuanyuan Li Zhenzhong Yong Kunjie Wu Yan Zhang Jin Wang Dongmei Hu Key Laboratory of Multifunctional and Smart Systems Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China College of Textile and Clothing Engineering of Soochow University Suzhou 215021China

Wireless communication technology is indispensable in our daily lives,but it also results in serious electromagnetic radiation ***,developing smart electromagnetic interference shielding materials with adjustable electromagnetic wave(EMW)responses holds significant promise for future electromagnetic shielding *** this study,we propose an electromagnetic shielding switch(ESS)characterized by tunable electromagnetic shielding performance achieved by fabricating a three-dimensional(3D)carbon nanotube-based spacer fabric(CNT-SF)and modifying CNT-SF with chemical vapor deposition(CCNT-SF).The CCNT-SF displays direction-dependent electrical conductivity by manipulating the warp and weft density,measuring 128 S/m transversely and 447 S/m *** characteristic allows the CCNT-SF to transmit or shield EMW by adjusting the angle of EMW incidence through fabric rotation,resulting in anisotropic electromagnetic shielding performance(33 dB transversely and 87 dB vertically).This feature enables switchable shielding with an on/off ratio of ***,the unique 3D structure confers excellent mechanical properties on the fabric,with compressive strength reaching 120 *** a flexible,lightweight,and mechanically robust ESS,the CCNT-SF holds promising prospects for mitigating the challenges of increasingly severe and intricate electromagnetic environments.

关键词： carbon nanotube spacer fabric electromagnetic shielding impact resistance joule heating electromagnetic shielding switch

In situ biosynthesis of bacterial cellulose hydrogel spheroids with tunable dimensions

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Journal of Bioresources and Bioproducts 2024年第1期9卷 90-101页

作者： Bianjing Sun Ping Wang Jingang Zhang Jianbin Lin Lingling Sun Xiaokun Wang Chuntao Chen dongping Sun Institute of Chemicobiology and Functional Materials School of Chemistry and Chemical EngineeringNanjing University of Science and TechnologyNanjing 210094China Zhonghao Chenguang Chemical Research Institute Co. Ltd.Zigong 643201China

Bacterial cellulose(BC)hydrogel spheroid plays a significant role in diverse fields due to its spatial 3D structure and *** the present work,a series of BC spheroids with controllable size and shape was obtained via an in situ *** factors for fabricating BC spheroid in-cluding inoculum concentration of 1.35×10^(3)CFU/mL,shaking speeds at 100 r/min,and 48-96 h incubation time during the biosynthetic process,were comprehensively *** operable mechanism model for tuning the size of BC spheroids from 0.4 to 5.0 mm was proposed with a fresh feeding medium strategy of dynamic *** resulting BC spheroids exhibit an inter-active 3D network of nanofibers,a crystallinity index of 72.3%,a specific surface area of 91.2 m^(2)/g,and good *** study reinforces the understanding of BC spheroid forma-tion and explores new horizons for the design of BC spheroids-derived functional matrix materials for medical care.

关键词： In situ biosynthesis Bacterial cellulose Hydrogel Spheroid Tunable dimension

Tuning microstructures of TC4 ELI to improve explosion resistance

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Defence Technology（防务技术） 2024年第3期33卷 78-99页

作者： Changle Zhang Yangwei Wang Lin Wang Zixuan Ning Guoju Li dongping Chen Zhi-Wei Yan Yuchen Song Xucai Wang School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing 100081China State Key Laboratory of Explosive Science and Technology Beijing Institute of TechnologyBeijing 100081China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China School of Aeronautical Engineering Zhengzhou University of AeronauticsHenan ProvinceZhengzhou 450046China Shanxi Jiangyang Chemical Co. Ltd.Shanxi ProvinceTaiyuan 030041China Shandong Institute of Non-metallic Materials Shandong ProvinceJinan 250031China

A reasonable heat treatment process for TC4 ELI titanium alloy is crucial to tune microstructures to improve its explosion ***,there is limited investigation on tuning microstructures of TC4 ELI to improve explosion ***,the current challenge is quantifying microstructural changes'effects on explosion resistance and incorporating microstructural changes into finite element *** work aims to tune microstructures to improve explosion resistance and elucidate their anti-explosion mechanism,and find a suitable method to incorporate microstructural changes into finite element *** this work,we systematically study the deformation and failure characteristics of TC4 ELI plates with varying microstructures using an air explosion test and LS-DYNA finite element *** Johnson-Cook(JC)constitutive parameters are used to quantify the effects of microstructural changes on explosion resistance and incorporate microstructural changes into finite element *** of the heat treatment,one plate has equiaxed microstructure and the other has bimodal *** convex of the plate after the explosion has a quadratic relationship with the charge mass,and the simulation results demonstrate high reliability,with the error less than 17.5%.Therefore,it is feasible to obtain corresponding JC constitutive parameters based on the differences in microstructures and mechanical properties and characterize the effects of microstructural changes on explosion *** bimodal target exhibits excellent deformation *** response of bimodal microstructure to the shock wave may be more intense under explosive *** well-coordinated structure of the bimodal target enhances its resistance to deformation.

关键词： Microstructure Finite element modelling Parameter optimization Failure characteristics Explosion resistance

Carbene-Catalyzed Asymmetric Ring-Opening Reaction of Biaryl Lactams to Access Axially Chiral Biaryls

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Chinese Journal of Chemistry 2024年第15期42卷 1734-1740页

作者： Guanjie Wang Guowei Yuan Chenlong Wei Ye Zhang Haibin Zhu Weiqi Yang dongping Shi Xiaoxiang Zhang Zhenqian Fu Institute of Advanced Materials Nanjing Tech UniversityNanjingJiangsu 211816China Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources College of Chemical EngineeringNanjing Forestry UniversityNanjingJiangsu 210037China

Axially chiral biaryls represent the most important class of atropisomers,and they widely exist in natural products and biologically active *** also constitute a unique scaffold for chiral ligands and catalysts in organic *** development of synthetic methods to obtain such chiral compounds has received widespread attention,among which catalytically atroposelective ring-opening of configurationally labile compounds represents one of the most attractive *** substrates with strained cyclic structures,such as the renowned Bringmann's lactones,can undergo asymmetric transformation into stable *** advancement primarily relies on metal catalyst combined with well-designed chiral ligands,the approaches utilizing organocatalysis as a critical resolution strategy are notably *** this study,we disclosed a N-heterocyclic carbene(NHC)-catalyzed asymmetric ring-opening reaction of biaryl lactams via direct atroposelective nucleophilic *** optimized bulky carbene catalyst ensures that the reaction can proceed under mild conditions,affording the desired product with good to excellent yields and atroposelectivity.

关键词： N-Heterocyclic carbene Axially chiral biaryls Organocatalysis Ring-opening reactions Dibenzo cyclic lactams Axially chiral amino acids Amide C-N bond activation Atropisomerism Asymmetric catalysis Lactams