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A Long-Time-Step-Permitting Tracer Transport Model on the Regular Latitude–Longitude Grid

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Advances in Atmospheric Sciences 2024年第3期41卷 493-508页

作者： Jianghao li li DONG Key Laboratory of Earth System Modeling and Prediction China Meteorological AdministrationBeijing 100081China State key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric Physics(IAP)Chinese Academy of SciencesBeijing 100029China State Key Laboratory of Severe Weather(LaSW) Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

If an explicit time scheme is used in a numerical model, the size of the integration time step is typically limited by the spatial resolution. This study develops a regular latitude–longitude grid-based global three-dimensional tracer transport model that is computationally stable at large time-step sizes. The tracer model employs a finite-volume flux-form semiLagrangian transport scheme in the horizontal and an adaptively implicit algorithm in the vertical. The horizontal and vertical solvers are coupled via a straightforward operator-splitting technique. Both the finite-volume scheme's onedimensional slope-limiter and the adaptively implicit vertical solver's first-order upwind scheme enforce monotonicity. The tracer model permits a large time-step size and is inherently conservative and monotonic. Idealized advection test cases demonstrate that the three-dimensional transport model performs very well in terms of accuracy, stability, and efficiency. It is possible to use this robust transport model in a global atmospheric dynamical core.

关键词： tracer transport numerical stability latitude–longitude grid

基于粒子群算法的复杂山区铁路土方调配与取弃土场选址协同优化

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铁道科学与工程学报 2024年第3期21卷 1202-1212页

作者：吕春妍蒲浩宋陶然李伟彭利辉钟晶徐占军中南大学土木工程学院湖南长沙410075 高速铁路建造技术国家工程研究中心湖南长沙410075 中国中铁股份有限公司北京100039 中铁第四勘察设计院集团有限公司湖北武汉430063 湖南中大设计院有限公司湖南长沙410018

复杂山区铁路线路土方调配及取弃土场选址对铁路项目的成本、工期、安全性、环境影响程度等产生长久深远影响,二者之间存在着复杂关联耦合关系。然而,既有方法忽略了上述联系,难以实现铁路线路土方调配与取弃土场选址协同优化。对于复... 详细信息

复杂山区铁路线路土方调配及取弃土场选址对铁路项目的成本、工期、安全性、环境影响程度等产生长久深远影响,二者之间存在着复杂关联耦合关系。然而,既有方法忽略了上述联系,难以实现铁路线路土方调配与取弃土场选址协同优化。对于复杂山区铁路线路,构建了融合调配段落划分点、土方调配量、取弃土场的统一自变量集合,考虑了土方调配、取弃土场选址复杂约束,以土方调配成本、取弃土场建设成本及便道建设成本的综合费用为目标函数,集成综合基础信息子系统、土方调配优化子系统与取弃土场选址优化子系统,建立了土方调配与取弃土场选址的协同优化模型。为求解此协同优化模型,提出一种基于粒子群算法的累进求解策略。首先根据线路划分土方调配段落,进入土方调配优化子系统求得土方调配解,借助移动窗口法构建取弃土场备选池,进入取弃土场选址优化子系统求得取弃土场址解;其次,基于粒子群算法通过更新线路土方调配段落划分来累进迭代寻求最优解。以某复杂山区铁路为例,对铁路线路土方调配及取弃土场选址协同优化模型进行案例验证,与人工方案相比,最终机选最优方案可节省13.77%的综合费用。测试结果表明本方法的有效性,可提高铁路土方调配与取弃土场选址求解效率,为设计人员提供参考。

关键词：铁路线路土方调配取弃土场选址协同优化累进求解算法

Meta label associated loss for fine-grained visual recognition

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Science China(Information Sciences) 2024年第6期67卷 230-247页

作者： Yanchao li Fu XIAO Hao li Qun li Shui YU School of Computer Science Nanjing University of Posts and Telecommunications School of Network Engineering Zhoukou Normal University School of Computer Science University of Technology Sydney

Recently, intensive attempts have been made to design robust models for fine-grained visual recognition, most notably are the impressive gains for training with noisy labels by incorporating a reweighting strategy into a meta-learning framework. However, it is limited to up or downweighting the contribution of an instance for label reweighting approaches in the learning process. To solve this issue, a novel noise-tolerant method with auxiliary web data is proposed. Specifically, first, the associations made from embeddings of well-labeled data with those of web data and back at the same class are measured. Next, its association probability is employed as a weighting fusion strategy into angular margin-based loss, which makes the trained model robust to noisy datasets. To reduce the influence of the gap between the well-labeled and noisy web data, a bridge schema is proposed via the corresponding loss that encourages the learned embeddings to be coherent. Lastly, the formulation is encapsulated into the meta-learning framework, which can reduce the overfitting of models and learn the network parameters to be noise-tolerant. Extensive experiments are performed on benchmark datasets, and the results clearly show the superiority of the proposed method over existing state-of-the-art approaches.

关键词： label associated loss weighting noisy samples fine-grained visual recognition noise-tolerant learning meta-learning

Indole-3-acetic acid,a potential therapeutic target in Alzheimer's disease

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Science Bulletin 2024年第2期69卷 146-147页

作者： Jinghong li Department of Chemistry Center for Bioanalytical ChemistryKey Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology(Ministry of Education)Tsinghua UniversityBeijing 100084China

Alzheimer's disease(AD)is a chronic and progressive neurodegenerative disease that is characterized by the presence of amyloid-β(Ap)plaques,hyperphosphorylated microtubule-associated tau protein(p-tau)neurofibrillary tangles and neuronal degeneration.According to recent data,AD is the most common global cause of dementia in the elderly.Although billions of dollars have been invested in research,there is still no effective drug for the treatment of AD;consequently,this disease imposes a huge burden on individuals,families,and healthcare systems[1,2].

关键词： Alzheimer tau degeneration

Wood of trees:Cellular structure,molecular formation,and genetic engineering

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Journal of Integrative Plant Biology 2024年第3期66卷 443-467页

作者： Yingying Zhu Laigeng li State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems and College of Ecology Lanzhou UniversityLanzhou 730000China National Key Laboratory of Plant Molecular Genetics CAS Center for Excellence in Molecular Plant SciencesChinese Academy of SciencesShanghai 200032China

Wood is an invaluable asset to human society due to its renewable nature,making it suitable for both sustainable energy production and material manufacturing.Additionally,wood derived from forest trees plays a crucial role in sequestering a significant portion of the carbon dioxide fixed during photosynthesis by terrestrial plants.Nevertheless,with the expansion of the global population and ongoing industrialization,forest coverage has been substantially decreased,resulting in significant challenges for wood production and supply.Wood production practices have changed away from natural forests toward plantation forests.Thus,understanding the underlying genetic mechanisms of wood formation is the foundation for developing high-quality,fast-growing plantation trees.Breeding ideal forest trees for wood production using genetic technologies has attracted the interest of many.Tremendous studies have been carried out in recent years on the molecular,genetic,and cell-biological mechanisms of wood formation,and considerable progress and findings have been achieved.These studies and findings indicate enormous possibilities and prospects for tree improvement.This review will outline and assess the cellular and molecular mechanisms of wood formation,as well as studies on genetically improving forest trees,and address future development prospects.

关键词： cambium cell wall Populus wood formation xylem

Current Status and Perspectives of Dual-Atom Catalysts Towards Sustainable Energy Utilization

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Nano-Micro Letters 2024年第7期16卷 402-440页

作者： Yizhe li Yajie li Hao Sun liyao Gao Xiangrong Jin Yaping li Zhi LV lijun Xu Wen liu Xiaoming Sun State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science EngineeringCollege of ChemistryBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China Xinjiang Coal Mine Mechanical and Electrical Engineering Technology Research Center Xinjiang Institute of EngineeringUrumqi 830023Xinjiang Uygur Autonomous RegionPeople’s Republic of China

The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.

关键词： Dual-atom catalysts Synergetic effect Electrocatalysis Oxygen reduction reaction CO_(2)reduction reaction Hydrogen evolution reaction N2 reduction reaction

Challenges in li-ion battery high-voltage technology and recent advances in high-voltage electrolytes

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Journal of Energy Chemistry 2024年第4期91卷 73-98页

作者： Jianguo liu Baohui li Jinghang Cao Xiao Xing Gan Cui Shandong Key Laboratory of Oil&Gas Storage and Transportation Safety College of Pipeline and Civil EngineeringChina University of Petroleum(East China)Qingdao 266580ShandongChina

The electrolyte directly contacts the essential parts of a lithium-ion battery,and as a result,the electrochemical properties of the electrolyte have a significant impact on the voltage platform,charge discharge capacity,energy density,service life,and rate discharge performance.By raising the voltage at the charge/discharge plateau,the energy density of the battery is increased.However,this causes transition metal dissolution,irreversible phase changes of the cathode active material,and parasitic electrolyte oxidation reactions.This article presents an overview of these concerns to provide a clear explanation of the issues involved in the development of electrolytes for high-voltage lithium-ion batteries.Additionally,solidstate electrolytes enable various applications and will likely have an impact on the development of batteries with high energy densities.It is necessary to improve the high-voltage performance of electrolytes by creating solvents with high thermal stabilities and high voltage resistance and additives with superior film forming performance,multifunctional capabilities,and stable lithium salts.To offer suggestions for the future development of high-energy lithium-ion batteries,we conclude by offering our own opinions and insights on the current development of lithium-ion batteries.

关键词： lithium-ion battery High voltage Electrolyte additive Solid electrolyte

车联网环境下充电桩健康状态综合评估与短期预测方法研究

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电力信息与通信技术 2022年第7期20卷 109-116页

作者：黄焘彭科程旭李陶然李强南方电网电动汽车服务有限公司广东深圳518000

针对国内充电桩在使用过程中存在虚警率过高、故障不能复现以及故障诊断时间过长的问题,文章提出一种车联网环境下充电桩健康状态综合评估与预测方法。首先,从安全性能和电气性能2个角度出发,构建递阶层次充电桩健康状态综合评估体系;然... 详细信息

针对国内充电桩在使用过程中存在虚警率过高、故障不能复现以及故障诊断时间过长的问题,文章提出一种车联网环境下充电桩健康状态综合评估与预测方法。首先,从安全性能和电气性能2个角度出发,构建递阶层次充电桩健康状态综合评估体系;然后,采用熵权法初始化各评估指标的权重,引入健康因子动态衡量各评估指标的综合权重,以期实现充电桩健康状态的动态评估;最后,采用马尔可夫模型预测充电桩健康短期的健康状态及剩余寿命。以深圳市某充电站系统为例,以充电桩状态评估与短期预测示例,验证了该方法的有效性。

关键词：车联网安全性能电气性能健康状态评估马尔可夫模型

A li_(3)P nanoparticle dispersion strengthened ultrathin li metal electrode for high energy density rechargeable batteries

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Nano Research 2024年第5期17卷 4031-4038页

作者： lin Fu Xiancheng Wang Bao Zhang Zihe Chen Yuanjian li Yongming Sun Provincial Guizhou Key Laboratory of Green Chemical and Clean Energy Technology School of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China School of Physical and Mathematical Sciences Nanyang Technological UniversitySingapore 637371Singapore Institute of Materials Research and Engineering Agency for Science Technology and Research(A*STAR)Singapore 138634Singapore

Achievement of lithium(li)metal anode with thin thickness(e.g.,≤30µm)is highly desirable for rechargeable high energy density batteries.However,the fabrication and application of such thin li metal foil electrode remain challenging due to the poor mechanical processibility and inferior electrochemical performance of metallic li.Here,mechanico-chemical synthesis of robust ultrathin li/li_(3)P(LLP)composite foils(~15µm)is demonstrated by employing repeated mechanical rolling/stacking operations using red P and metallic li as raw materials.The in-situ formed li+-conductive li_(3)P nanoparticles in metallic li matrix and their tight bonding strengthen the mechanical durability and enable the successful fabrication of free-standing ultrathin li metal composite foil.Besides,it also reduces the electrochemical li nucleation barrier and homogenizes li plating/stripping behavior.When matching to high-voltage liCoO_(2),the full cell with a low negative/positive(N/P)capacity ratio of~1.5 offers a high energy density of~522 W·h·kg^(-1) at 0.5 C based on the mass of cathode and anode.Taking into account its facile manufacturing,potentially low cost,and good electrochemical performance,we believe that such an ultrathin composite li metal foil design with nanoparticle-dispersion-strengthened mechanism may boost the development of high energy density li metal batteries.

关键词： lithium metal anode high energy density battery mechanico-chemical synthesis ultrathin li/li_(3)P composite foil low negative/positive capacity ratio