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Ferromagnetism and insulating behavior with a logarithmic temperature dependence of resistivity in Pb_(10-x)Cux(PO_(4))_(6)O

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 106-111页

作者： yuhang zhang Cong Liu Xiyu Zhu Hai-Hu Wen Center for Superconducting Physics and Materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Recent claim of discovering above-room-temperature superconductivity(Tc≈400 K)at ambient pressure in copper doped apatite Pb10(PO_(4))_(6)O has stimulated world-wide enthusiasm and impulse of motion.A lot of follow-up works have been carried out with controversial *** check whether superconductivity is really present or absent in the material,we need samples which should have a rather pure phase of Pb_(10-x)Cux(PO_(4))_(6)*** we report the characterization results from the Pb_(10-x)Cux(PO_(4))_(6)O with a fraction of about 97 wt.%inferred from the fitting to the X-ray diffraction pattern,if assuming Cu2S as the only *** resistivity measurements show that it is a semiconductor characterized roughly by a ln(1/T)temperature dependence in wide temperature region without trace of *** measurements show that it has a general ferromagnetic signal with a weak superparamagnetic *** grains of the sample show clear interactions with a Nb Fe B *** detected Cu concentration is much lower than the expected nominal *** results show the absence of metallicity and superconductivity in Pb_(10-x)Cux(PO_(4))_(6)O at ambient pressure,and suggest the presence of strong correlation effect.

关键词： superconductivity Pb10(PO4)6O ferromagnetic correlation effect

A novel predictive braking energy recovery strategy for electric vehicles considering motor thermal protection

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Science China(Technological Sciences) 2024年第4期67卷 1253-1269页

作者： YANG Chao SUN TongLin YANG LiuQuan zhang yuhang WANG WeiDa School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100084China

Braking energy recovery(BER)aims to recover the vehicle's kinetic energy by coordinating the motor and mechanical braking torque to extend the driving range of the electric vehicle(EV).To achieve this goal,the motor/generator mode requires frequent switching and prolonged operation during *** this case,the motor temperature will unavoidably rise,potentially triggering motor thermal protection(MTP).Activating MTP increases the risk of motor component failure,and the EV typically disables the BER ***,maximizing BER while reducing the risk of motor overheating is a challenging *** address this issue,this article proposes a predictive BER strategy with MTP using the non-smooth Pontryagin Minimum Principle(NSPMP)for ***,a Markov long short-term memory(MLSTM)model is designed to obtain future velocity ***,the BER problem with MTP in the studied EV is embedded in a model predictive control(MPC)***,under the MPC framework,the NSPMP strategy is proposed to resolve the problem of ***,the performance of the proposed strategy is verified through simulation and a hardware-in-loop *** results show that in two real-world driving cycles,compared to the rule-based strategy,the proposed strategy reduced power consumption by 1.24%and0.96%,respectively,and effectively limited motor ***,under global cycle conditions,this strategy demonstrated better MTP control performance compared to other benchmark strategies.

关键词： electric vehicle braking energy recovery strategy motor thermal protection non-smooth PMP

Advances in methane emissions from agricultural sources:Part *** and mitigation

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Journal of Environmental Sciences 2024年第6期140卷 279-291页

作者： Xiaokun Wu Ying zhang Yinghui Han Yagang zhang yuhang zhang Xiaodan Cheng Pei Zhong Xue Yuan Yuanxun zhang Zhengqiang Li State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071003China College of Resources and Environment University of Chinese Academy of SciencesBeijing 101408China Interdisciplinary Mathematics Institute University of South CarolinaColumbiaSC 29208United States Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China

Methane is one of the major greenhouse gases(GHGs)and agriculture is recognized as its primary *** accounting is a prerequisite for developing effective agriculture mitigation *** this review,methane accounting methods and research status for various agricultural emission source including rice fields,animal enteric fermentation and livestock and poultry manure management were overview,and the influencing factors of each emission source were analyzed and *** the same time,it analyzes the different research efforts involving agricultural methane accounting and makes recommendations based on the actual ***,mitigation strategies based on accounting results and actual situation are *** review aims to provide basic data and reference for agriculture-oriented countries and regions to actively participate in climate action and carry out effective methane emission mitigation.

关键词： Methane emission Agricultural sources Accounting methodology Mitigation Emission influencing factors

Near infrared emissions from both high efficient quantum cutting (173%) and nearly-pure-color upconversion in NaY(WO_(4))_(2):Er^(3+)/Yb^(3+) with thermal management capability for silicon-based solar cells

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Light(Science & Applications) 2024年第1期13卷 113-126页

作者： Duan Gao Baojiu Chen Xuezhu Sha yuhang zhang Xin Chen Li Wang Xizhen zhang Jinsu zhang Yongze Cao Yichao Wang Lei Li Xiangping Li Sai Xu Hongquan Yu Lihong Cheng School of Science Dalian Maritime UniversityDalian 116026 LiaoningChina

Raising photoelectric conversion efficiency and enhancing heat management are two critical concerns for siliconbased solar *** this work,efficient Yb^(3+) infrared emissions from both quantum cutting and upconversion were demonstrated by adjusting Er^(3+) and Yb^(3+) concentrations,and thermo-manage-applicable temperature sensing based on the luminescence intensity ratio of two super-low thermal quenching levels was discovered in an Er^(3+)/Yb^(3+) codoped tungstate *** quantum cutting mechanism was clearly decrypted as a two-step energy transfer process from Er^(3+) to Yb^(3+).The two-step energy transfer efficiencies,the radiative and nonradiative transition rates of all interested 4 f levels of Er^(3+) in NaY(WO_(4))_(2) were confirmed in the framework of Föster-Dexter theory,Judd-Ofelt theory,and energy gap law,and based on these obtained efficiencies and rates the quantum cutting efficiency was furthermore determined to be as high as 173%in NaY(WO_(4))_(2):5 mol%Er^(3+)/50 mol%Yb^(3+) *** and nearly pure infrared upconversion emission of Yb3+under 1550 nm excitation was achieved in Er^(3+)/Yb^(3+)co-doped NaY(WO_(4))_(2) by adjusting Yb^(3+) doping *** Yb^(3+) induced infrared upconversion emission enhancement was attributed to the efficient energy transfer ^(4)I_(11/2)(Er^(3+))+^(2)F_(7/2)(Yb^(3+))→^(4)I_(15/2)(Er^(3+))+^(2)F_(5/2)(Yb^(3+))and large nonradiative relaxation rate of ^(4)I_(9/2).Analysis on the temperature sensing indicated that the NaY(WO_(4))_(2):Er^(3+)/Yb^(3+)serves well the solar cells as thermos-managing ***,it was confirmed that the fluorescence thermal quenching of ^(2)H_(11/2)/^(4)S_(3/2) was caused by the nonradiative relaxation of ^(4)S_(3/2).All the obtained results suggest that NaY(WO_(4))_(2):Er^(3+)/Yb^(3+) is an excellent material for silicon-based solar cells to improve photoelectric conversion efficiency and thermal management.

关键词： quantum thermal relaxation

Signature of Superconductivity in Pressurized La_(4)Ni_(3)O_(10)

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Chinese Physics Letters 2024年第1期41卷 77-84页

作者：李庆张英杰项浙宁张宇航祝熙宇闻海虎 National Laboratory of Solid State Microstructures and Department of Physics Center for Superconducting Physics and MaterialsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

The discovery of high-temperature superconductivity near 80K in bilayer nickelate La_(3)Ni_(2)O_(7)under high pressures has renewed the exploration of superconducting nickelate in bulk *** extension of superconductivity in other nickelates in a broader family is also ***,we report the experimental observation of superconducting signature in trilayer nickelate La_(4)Ni_(3)O_(10)under high *** using a modified solgel method and post-annealing treatment under high oxygen pressure,we successfully obtained polycrystalline La_(4)Ni_(3)O_(10)samples with different transport behaviors at ambient *** we performed high-pressure electrical resistance measurements on these samples in a diamond-anvil-cell ***,the signature of possible superconducting transition with a maximum transition temperature(T_(c))of about 20K under high pressures is observed,as evidenced by a clear drop of resistance and the suppression of resistance drops under magnetic *** the resistance drop is sample-dependent and relatively small,it appears in all of our measured *** argue that the observed superconducting signal is most likely to originate from the main phase of La_(4)Ni_(3)O_(10).Our findings will motivate the exploration of superconductivity in a broader family of nickelates and shed light on the understanding of the underlying mechanisms of high-T_(c) superconductivity in nickelates.

关键词： materials superconductivity signature

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数智技术介入下的紫砂器形态再设计

南京艺术学院学报（美术与设计） 2024年第3期 92-97,I0003页

作者：王欣张雨航南京艺术学院设计学院江苏南京210013 无锡供春人工智能科技有限公司江苏宜兴214200

本文探讨了数字智能技术在紫砂器设计和制作中的融合及其对传统手工艺和文化传承的影响。强调了这些技术在适应现代市场需求、提升设计创新与效率方面的重要性。同时,探讨了如何在保持传统工艺精粹的同时,融入现代技术。最后通过实践案... 详细信息

本文探讨了数字智能技术在紫砂器设计和制作中的融合及其对传统手工艺和文化传承的影响。强调了这些技术在适应现代市场需求、提升设计创新与效率方面的重要性。同时,探讨了如何在保持传统工艺精粹的同时,融入现代技术。最后通过实践案例,分析了数智技术在紫砂器设计中的具体应用以及它与传统手工艺之间的互动关系。

关键词：数智技术紫砂器设计创新

桨叶分段线性扭转对降低旋翼振动载荷的作用分析

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Transactions of Nanjing University of Aeronautics and Astronautics 2024年第3期41卷 278-288页

作者：张宇杭韩东南京航空航天大学航空学院直升机动力学全国重点实验室南京210016

研究了用桨叶分段线性扭转来降低旋翼振动载荷。使用基于弹性梁的旋翼模型用于预测旋翼振动载荷。采用4片桨叶旋翼作为基准旋翼,桨叶形状与UH-60直升机桨叶相似。桨叶被划分为内、中、外3段,讨论了各段扭转对载荷的影响。低速时桨叶每... 详细信息

研究了用桨叶分段线性扭转来降低旋翼振动载荷。使用基于弹性梁的旋翼模型用于预测旋翼振动载荷。采用4片桨叶旋翼作为基准旋翼,桨叶形状与UH-60直升机桨叶相似。桨叶被划分为内、中、外3段,讨论了各段扭转对载荷的影响。低速时桨叶每一段的扭转都能减少桨毂四阶垂向力。当以80 km/h前飞时,中段-24°/R的扭转可使其降低99.5%。桨叶内段的扭转不利于降低桨毂四阶滚转和俯仰力矩,另外两段的扭转则可以在大多数前飞速度时控制这2个振动力矩。使用参数扫描以尽可能降低旋翼振动载荷。降低四阶垂向力方面,低速时桨叶所有段都需要扭转,而高速时未扭转的桨叶表现更好。降低四阶滚转和俯仰力矩方面,在低速时需要桨叶外段高度扭转,而在中高速时则需要桨叶中段的扭转。

关键词：直升机旋翼振动载荷分段桨叶扭转桨毂垂向力滚转力矩俯仰力矩

基于模态分解及GRU-XGBoost短期电力负荷预测

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电网与清洁能源 2024年第4期40卷 18-27,34页

作者：冉启武张宇航陕西理工大学电气工程学院陕西汉中723000

精确的短期电力负荷预测能有效提高电力系统运营水平。针对电力负荷数据受多种因素影响,波动性和随机性强等问题,提出了一种基于模态分解及混合模型的负荷预测方法。首先,采用主成分分析法(principal component analysis,PCA)对负荷特... 详细信息

精确的短期电力负荷预测能有效提高电力系统运营水平。针对电力负荷数据受多种因素影响,波动性和随机性强等问题,提出了一种基于模态分解及混合模型的负荷预测方法。首先,采用主成分分析法(principal component analysis,PCA)对负荷特征向量进行处理,去掉冗余信息,再用完全自适应噪声集合经验模态分解(complete ensemble empirical mode decomposition with adaptive noise,CEEMDAN)将历史负荷分解为简化的几个子序列;其次,选择引入样本熵(sample entropy,SE)来计算子序列熵值,将相近的子序列重构得到随机、细节、低频和趋势分量后选用不同结构门控循环单元(gate recurrent unit,GRU)对不同分量类型进行预测,再使用极致梯度提升模型(extreme gradient boosting,XGBoost)对各分量残差进行拟合,各重组序列的预测值为GRU预测值与XBGoost拟合值之和,重组各序列得到最终预测值。选取3年时电力负荷数据进行实验,结果表明,所提模型的均方根误差(root mean square error,RMSE)、平均绝对百分比误差(mean absolutepercentage error,MAPE)和平均绝对误差(mean absolute error,MAE)分别为370.676 MW、99.07%和246.89 MW,与单一模型和混合模型相比,实现了评价指标的明显减少。

关键词：负荷预测主成分分析 CEEMDAN 样本熵门控循环单元极致梯度提升模型

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产前超声诊断胎儿先天性梨状窝瘘1例

中华围产医学杂志 2024年第3期27卷 238-240页

作者：宋宴鹏李明张宇航青岛市胶州中心医院特检科青岛266300 太仓市第一人民医院超声科苏州215400

本文报道1例产前超声诊断的胎儿先天性梨状窝瘘病例。孕妇孕17周^(+2)产前常规超声检查发现胎儿左侧颈部椭圆形囊性包块,孕23周行产前系统超声筛查发现胎儿左侧颈部囊性包块,在颈部冠状位切面探及囊性包块上端与喉部有一细窄窦道形成,... 详细信息

本文报道1例产前超声诊断的胎儿先天性梨状窝瘘病例。孕妇孕17周^(+2)产前常规超声检查发现胎儿左侧颈部椭圆形囊性包块,孕23周行产前系统超声筛查发现胎儿左侧颈部囊性包块,在颈部冠状位切面探及囊性包块上端与喉部有一细窄窦道形成,考虑先天性梨状窝瘘。生后21 d,患儿左侧颈部包块明显隆起,吃奶时出现呛咳及呼吸时伴有喘鸣音。生后21 d超声检查及生后25 d CT检查均发现左侧颈部囊性包块及囊内有气体。生后26 d全身麻醉下行颈部开放性囊肿切除术+高位瘘管缝扎及瘘管切除术,术中诊断为先天性梨状窝瘘。患儿术后愈合良好,随访至3月龄未出现并发症。

关键词：梨状隐窝瘘胎儿超声检查,产前