Prediction of high-speed train delay propagation based on causal text information

The delay-causing text data contain valuable information such as the specific reasons for the delay,location and time of the disturbance,which can provide an efficient support for the prediction of train delays and improve the guidance of train control efficiency.Based on the train operation data and delay-causing data of the Wuhan-Guangzhou high-speed railway,the relevant algorithms in the natural language processing field are used to process the delay-causing text data.It also integrates the train operatingenvironment information and delay-causing text information so as to develop a cause-based train delay propagation prediction model.The Word2vec model is first used to vectorize the delay-causing text description after word segmentation.The mean model or the term frequency-inverse document frequency-weighted model is then used to generate the delay-causing sentence vector based on the original word vector.Afterward,the train operating-environment features and delay-causing sentence vector are input into the extreme gradient boosting(XGBoost)regression algorithm to develop a delay propagation prediction model.In this work,4 text feature processing methods and 8 regression algorithms are considered.The results demonstrate that the XGBoost regression algorithm has the highest prediction accuracy using the test features processed by the continuous bag of words and the mean models.Compared with the prediction model that only considers the train-operating-environment features,the results show that the prediction accuracy of the model is significantly improved with multi-ple regression algorithms after integrating the delay-causing feature.

Shining Light on Anion-Mixed Nanocatalysts for Efficient Water Electrolysis: Fundamentals, Progress, and Perspectives

Hydrogen with high energy density and zero carbon emission is widely acknowledged as the most promising candidate toward world’s carbon neutrality and future sustainable eco-society.Water-splitting is a constructive technology for unpolluted and high-purity H2 production,and a series of non-precious electrocatalysts have been developed over the past decade.To further improve the catalytic activities,metal doping is always adopted to modulate the 3d-electronic configuration and electron-donating/accepting(e-DA)properties,while for anion doping,the electronegativity variations among different non-metal elements would also bring some potential in the modulations of e-DA and metal valence for tuning the performances.In this review,we summarize the recent developments of the many different anion-mixed transition metal compounds(e.g.,nitrides,halides,phosphides,chalcogenides,oxyhydroxides,and borides/borates)for efficient water electrolysis applications.First,we have introduced the general information of water-splitting and the description of anion-mixed electrocatalysts and highlighted their complementary functions of mixed anions.Furthermore,some latest advances of anion-mixed compounds are also categorized for hydrogen and oxygen evolution electrocatalysis.The rationales behind their enhanced electrochemical performances are discussed.Last but not least,the challenges and future perspectives are briefly proposed for the anion-mixed water dissociation catalysts.

Correction of a CADASIL point mutation using adenine base editors in hiPsCsandbloodvessel organoids

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic small vessel disease caused by mutations in the NOTCH3 gene. However, the pathogenesis of CADASIL remains unclear, and patients have limited treatment options. Here, we use human induced pluripotent stem cells (hiPSCs) generated from the peripheral blood mononuclear cells of a patient with CADASIL carrying a heterozygous NOTCH3 mutation (c.1261C>T, p.R421C) to develop a disease model. The correction efficiency of different adenine base editors (ABEs) is tested using the HEK293T-NOTCH3 reporter cell line. ABEmax is selected based on its higher efficiency and minimization of predicted off-target effects. Vascular smooth muscle cells (VSMCs) differentiated from CADASIL hiPSCs show NOTCH3 deposition and abnormal actin cytoskeleton structure, and the abnormalities are recovered in corrected hiPSC-derived VSMCs. Furthermore, CADASIL blood vessel organoids generated for in vivo modeling show altered expression of genes related to disease phenotypes, including the downregulation of cell adhesion, extracellular matrix organization, and vessel development. The dual adeno-associated virus (AAV) split-ABEmax system is applied to the genome editing of vascular organoids with an average editing efficiency of 8.82%. Collectively, we present potential genetic therapeutic strategies for patients with CADASIL using blood vessel organoids and the dual AAV split-ABEmax system.

如何拥抱智能时代--以化学学科为例

本文从人类社会发展的视角论述了拥抱智能时代的重要性,对第四次工业革命的核心技术--人工智能及其将如何影响人类社会做了简要描述;接着以化学学科的研究为例,通过介绍一些有代表性的研究工作,从基础、工具和应用三个层次,重点论述了机器智能如何改变学科研究范式以及如何帮助人类加快科学发现;最后,对人工智能与其他领域的结合提出了一些方法和路径.

Electrochemical Radical Borylation of Aryl Iodides

Herein,we report the first electrochemical strategy for the borylation of aryl iodides via a radical pathway using current as a driving force.A mild reaction condition allows an assorted range of readily available aryl iodides to be proficiently converted into synthetically valuable arylboronic esters under transition metal catalyst-free conditions.Moreover,this method also shows good functional group tolerance.Initial control mechanistic experiments reveal the formation of aryl radical as a key intermediate and the current plays an important role in the generation of radical intermediate.

Cu（I）-Catalyzed Asymmetric Cross-Coupling of N-Tosylhydrazones and Trialkyl- silylethynes： Enantioselective Construction of C（sp）--C（sp^3） Bonds

The first catalytic enantioselective C（sp）-C（sp^3） cross-coupling reaction between N-tosylhydrazones and trialkylsilylethynes in the presence of Cu（I） salts and chiral phosphoramidite ligands was developed. A series of svnthetically interesting, functionalized alkynes were obtained with moderate to good enanttiselectivities （up to 83% ee）. Cu（ll） carbene migratory insertion is proposed to be the enantio-determining step. KEYWORDS C（sp）--C（sp^3） cross-coupling, metal carbene, asymmetric catalysis, Cu（I） catalysts, N-tosylhydrazones

Resonance Mechanism Analysis of Large-scale Photovoltaic Power Plant

To analyze the resonance mechanism of a photovoltaic(PV)power plant,a simplified impedance model of the PV power plant is first established.The structure of the PV power plant is then introduced,and the reason for the resonance is obtained by analyzing the on-site situation and measured data of the PV power plant.Finally,a simple and effective solution is proposed based on the structure of the PV power plant and its existing facilities.The results of the engineering experiments and the stable operation of the PV power plant verify the effectiveness of the proposed method.

Novel Wind Power Grid-connection System Using Inductive Filtering Technology

Herein,a novel wind power grid-connection system based on inductive filtering is proposed to improve grid-connection compatibility,and is implemented in a 50-MW real system.First,the topology and wiring configuration of the proposed system are discussed.Thereafter,an equivalent circuit and mathematical model are established to reveal the filtering characteristics and resonance damping mechanism of the proposed system.Finally,a 50-MW wind farm-based experimental study,which is conducted to validate the effectiveness and availability of the system is discussed.The experimental results show that the main harmonics,power factor,voltage fluctuation,and flicker satisfy national standards.