Angewandte Chemie International Edition最新文献_第9页

In Situ Visualization of Lattice-Coherent Phase Oscillations and Active Brownian Motion of a Copper Catalyst During Hydrogen Oxidation. 氢氧化过程中铜催化剂晶格相干相振荡和活跃布朗运动的原位可视化。

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202515820

Yongzhao Wang,Chao Zhao,Panpan Liu,Shengnan Yue,Yuan Wen,Zhaoying Wang,Tongtong Gao,Praveen Chandramathy Surendran,Travis Jones,Feng Ding,Xing Huang

{"title":"In Situ Visualization of Lattice-Coherent Phase Oscillations and Active Brownian Motion of a Copper Catalyst During Hydrogen Oxidation.","authors":"Yongzhao Wang,Chao Zhao,Panpan Liu,Shengnan Yue,Yuan Wen,Zhaoying Wang,Tongtong Gao,Praveen Chandramathy Surendran,Travis Jones,Feng Ding,Xing Huang","doi":"10.1002/anie.202515820","DOIUrl":"https://doi.org/10.1002/anie.202515820","url":null,"abstract":"Structural dynamics govern the catalytic activity of metal nanoparticles (NPs), yet their atomic-scale mechanisms remain unclear. Using in situ transmission electron microscopy, we reveal redox-driven lattice-coherent Cu↔Cu2O phase oscillations in individual Cu NPs during hydrogen oxidation conditions. These oscillations generate active Brownian particles, wherein asymmetric H2 oxidation leads to directional motion that results in particle collisions and sintering. Crucially, the same active Brownian motion also triggers particle splitting, counteracting surface area loss and deactivation. Such active matter behavior arises from the formation of a head-tail morphology at critical H2:O2 ratios (e.g., 5:1), featuring a metallic-rich head and an oxide-dominated tail, with their volumetric balance dynamically shifting through competitive oxidation-reduction cycles. Quantitative analysis establishes a direct correlation between migration velocity and redox dynamics, revealing that the oxidation process significantly enhances particle mobility while the followed reduction process slows the velocity. Molecular dynamics (MD) simulations demonstrate that particle elongation and oxide tail fragmentation, accompanying particle migration, can be explained by asymmetric adhesion forces between the metallic/oxide phases and the silicon nitride support, alongside the redox reactions occurring on the particles. This work provides atomic-scale insights into catalyst dynamics under operando redox conditions, offering foundational knowledge for designing stable, high-performance catalytic systems.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"98 1","pages":"e202515820"},"PeriodicalIF":16.6,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A High Modulus, Multi-Stimuli Responsive, Interwoven Protein Network With Topologically Confined Micro-Association. 高模量、多刺激响应、具有拓扑限制微关联的交织蛋白网络。

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202516010

Tingjie Xu,Yibin Sun,Yu-Xiang Wang,Fengyi Jiang,Bo Hou,Ziyi Meng,Lianjie Xu,Yajie Liu,Wen-Hao Wu,Wen-Bin Zhang

{"title":"A High Modulus, Multi-Stimuli Responsive, Interwoven Protein Network With Topologically Confined Micro-Association.","authors":"Tingjie Xu,Yibin Sun,Yu-Xiang Wang,Fengyi Jiang,Bo Hou,Ziyi Meng,Lianjie Xu,Yajie Liu,Wen-Hao Wu,Wen-Bin Zhang","doi":"10.1002/anie.202516010","DOIUrl":"https://doi.org/10.1002/anie.202516010","url":null,"abstract":"All-protein-based materials are attractive for their genetic encodability, precise structure, and versatile functions, yet integrating mechanical strength, dynamic adaptability, and functional activity in one system remains challenging. Herein, we report a multi-stimuli-responsive, self-healing, all-protein-based network with an interwoven network topology, whose mechanics can be further reinforced by topologically confined micro-association upon tempering. The network was constructed by polymerizing pseudo[2]catenanes-which employ p53dim for entanglement and SpyTag(DA)-SpyCatcher complex for physical cyclization-that are opened into a star-like conformation. Network formation can be triggered by increasing concentration, calmodulin (CaM) binding, or light irradiation (when azoswitch-modified CaM is used). Subsequent tempering unfolds the SpyTag/SpyCatcher complex, inducing micro-association that acts as additional crosslinks within the topologically confined network. While the entangled architecture minimizes chain slippage, the micro-associations enhance crosslinking and stress dissipation, collectively improving mechanical properties and long-term stability. We further demonstrate its practical utility in controlled release and enzyme immobilization, establishing topological proteins as a versatile platform for designing genetically programmable, mechanically tunable, stimuli-responsive biomaterials.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"352 1","pages":"e202516010"},"PeriodicalIF":16.6,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanism of the Stoltz-Grubbs (KOtBu/Et3SiH) Silylation: Single-Electron Transfer is the Missing Link between the Heterolytic and Radical Pathways. Stoltz-Grubbs （KOtBu/Et3SiH）硅基化的机理：单电子转移是杂解和自由基途径之间缺失的一环。

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202517336

Ian D Jenkins,Ka Ho Chow,Elizabeth H Krenske

引用次数: 0

Quantitative Reactivity Profiling of Functional Arginine Residues in Human Cancer Cell Line Proteomes. 人类癌细胞蛋白质组中功能性精氨酸残基的定量反应性分析。

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202515603

Wenbo Zhao,Yuliang Tang,Yihui Gao,Qi Ding,Qiang Li,Wenyang Li,Xiaoguang Lei

{"title":"Quantitative Reactivity Profiling of Functional Arginine Residues in Human Cancer Cell Line Proteomes.","authors":"Wenbo Zhao,Yuliang Tang,Yihui Gao,Qi Ding,Qiang Li,Wenyang Li,Xiaoguang Lei","doi":"10.1002/anie.202515603","DOIUrl":"https://doi.org/10.1002/anie.202515603","url":null,"abstract":"Arginine, a critical amino acid for protein structure and function, is involved in enzyme catalysis and macromolecular interactions. However, selectively targeting its reactive guanidine group has been challenging. Here, we utilized a probe, AP-1, based on phenylglyoxal, which demonstrated remarkable chemical selectivity and reactivity toward arginine residues. Using activity-based protein profiling (ABPP), we explored the human proteome across four cancer cell lines, obtaining quantitative data for approximately 17 000 arginine residues. This analysis led to the identification of several previously unreported hyperreactive arginine residues, including R43 of PKM, R171 of LDHA, R172 of LDHB, R341 of CKB, R168 of EIF4A1, and R118 of FUBP1, which are crucial for protein function. Notably, the mutation of CKB's R341 inhibited cell proliferation and migration by downregulating energy supply. We also introduced ArGO-LDHA-1, a covalent inhibitor targeting LDHA's hyperreactive arginine residues, showing potential to enhance chemotherapy efficacy. This work highlights the biological significance of arginine residues and provides a platform for large-scale profiling of arginine reactivity.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"54 1","pages":"e202515603"},"PeriodicalIF":16.6,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Heterogenised Molecular Electrocatalyst for Round-the-Clock Green Hydrogen Production by Solar-Electrolyser and Zinc-Air Batteries. 太阳能电解和锌-空气电池24小时绿色制氢的多相分子电催化剂。

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202516482

Sukanta Saha,Yashwant Pratap Kharwar,Santanu Ghorai,Harshini V Annadata,Suhana Karim,Arnab Dutta

{"title":"A Heterogenised Molecular Electrocatalyst for Round-the-Clock Green Hydrogen Production by Solar-Electrolyser and Zinc-Air Batteries.","authors":"Sukanta Saha,Yashwant Pratap Kharwar,Santanu Ghorai,Harshini V Annadata,Suhana Karim,Arnab Dutta","doi":"10.1002/anie.202516482","DOIUrl":"https://doi.org/10.1002/anie.202516482","url":null,"abstract":"Solar energy-driven seawater electrolysis presents a sustainable method for producing high-purity green hydrogen to address the energy crisis. Developing a robust electrocatalyst for seawater splitting is crucial for green fuel production with solar integration. This study introduces a silica-anchored cobaloxime system as a multifunctional electrocatalyst for overall seawater splitting in conjunction with photovoltaic cells. The system achieves a solar-to-hydrogen generation efficiency of 14%, a power conversion efficiency of 17.4%, and a round-trip energy efficiency of 80%. A single-stack electrolyser using this catalyst produces an average of 0.82 mmol h-1 of green hydrogen and 0.44 mmol h-1 of oxygen, with a hydrogen conversion efficiency of approximately 80 kWh kg-1 under natural sunlight. The same catalyst also shows bidirectional O2 reduction and evolution activity, enabling solar energy storage through a rechargeable zinc-air battery (RZAB). A photovoltaic-RZAB-electrolyser triad was established for indirect green hydrogen production using stored renewable energy. The catalyst-containing RZAB system is effectively charged by a photovoltaic (PV) cell, achieving 25% energy efficiency, and facilitates seawater splitting without sunlight at an energy conversion efficiency of 84%. The strategic application of the catalyst as a multifunctional electrocatalyst enables sustainable green hydrogen production both during the day and night under practical conditions.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"17 1","pages":"e202516482"},"PeriodicalIF":16.6,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Molecular Design-Enabled Pyridinium-Based Metal Halide Glass Scintillators with Robust Glass-Forming Ability and Tailorable Radioluminescence. 分子设计使基于吡啶的金属卤化物玻璃闪烁体具有强大的玻璃形成能力和可定制的辐射发光。

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202518282

Zi-Lin He,Ya-Xin Luo,Jing-Hua Chen,Jian-Bin Luo,Jun-Hua Wei,Tian-Chi Wang,Qing-Peng Peng,Dai-Bin Kuang

{"title":"Molecular Design-Enabled Pyridinium-Based Metal Halide Glass Scintillators with Robust Glass-Forming Ability and Tailorable Radioluminescence.","authors":"Zi-Lin He,Ya-Xin Luo,Jing-Hua Chen,Jian-Bin Luo,Jun-Hua Wei,Tian-Chi Wang,Qing-Peng Peng,Dai-Bin Kuang","doi":"10.1002/anie.202518282","DOIUrl":"https://doi.org/10.1002/anie.202518282","url":null,"abstract":"Organic-inorganic hybrid metal halide (OIMH) glasses represent a promising class of functional materials due to their facile synthesis, high transparency, and composition tunability. However, a significant gap persists in the diversity of applicable glassy material systems and the availability of well-defined structural design guidelines compared to their crystalline counterparts. Herein, we synthesized a series of pyridine-based OIMH crystals exhibiting efficient luminescence and exceptional melting properties. Through systematic benzyl functionalization and phenyl substitution on the pyridinium cation, we have optimized both luminescence efficiency and glass-forming ability (GFA). Among them, (1-Bz-3-PhPy)2MnBr4 (1-Bz-3-PhPy = 1-benzyl-3-phenylpyridinium) displays the lowest melting temperature (Tm = 111.9 °C) and the highest glass transition temperature (Tg = 50.3 °C), yielding excellent GFA as indicated by a high Tg/Tm ratio of 0.84. The exceptional GFA is further demonstrated by the glass's remarkable stability, retaining an amorphous state even after annealing at 80 °C for 8 weeks. It also allows for co-melting with other easily crystallizable components, which facilitates the preparation of two-component glasses with precisely tunable radioluminescence properties. These advanced glassy materials provide opportunities for practical X-ray imaging and real-time visualization of multicolor radiation detection, further establishing new design paradigms for OIMH scintillators.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"19 1","pages":"e202518282"},"PeriodicalIF":16.6,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Novel α-KG/Fe(II)-Dependent Dioxygenases Catalyzing C1β-Hydroxylation and Construction of 5/7/6-Skeleton of Highly Oxygenated Taxoids. 新型α-KG/Fe（II）依赖性双加氧酶催化c1 β-羟基化及构建高氧类Taxoids的5/7/6-骨架

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202517041

Changkang Li,Yuxin Wang,Xinxin Yin,Xincheng Sun,Songyang Sui,Jimei Liu,Ridao Chen,Kebo Xie,Dawei Chen,Yaotian Han,Jungui Dai

{"title":"Novel α-KG/Fe(II)-Dependent Dioxygenases Catalyzing C1β-Hydroxylation and Construction of 5/7/6-Skeleton of Highly Oxygenated Taxoids.","authors":"Changkang Li,Yuxin Wang,Xinxin Yin,Xincheng Sun,Songyang Sui,Jimei Liu,Ridao Chen,Kebo Xie,Dawei Chen,Yaotian Han,Jungui Dai","doi":"10.1002/anie.202517041","DOIUrl":"https://doi.org/10.1002/anie.202517041","url":null,"abstract":"Here, we report the discovery and functional characterization of one novel taxane C1β-hydroxylase (TmT1βH), belonging to the α-ketoglutarate (α-KG)/Fe(II)-dependent dioxygenase family from Taxus × media cell cultures. The incubation of recombinant TmT1βH with 1β-dehydroxybaccatin IV (1) as a substrate led to the production of a major C1-hydroxylated product, baccatin IV (1a), and a minor product, 15-hydroxy-11(15→1)abeo-baccatin IV (1b), a non-classical 5/7/6-type taxane. Moreover, in vitro biochemical assays, molecular docking, and molecular dynamics simulation combined with site-directed mutagenesis revealed the critical amino acid residues for TmT1βH catalysis. Substrate specificity investigations revealed that TmT1βH preferred taxoids with high oxygenation level. Notably, we have also discovered a novel specific enzyme (Tm576) belonging to α-KG/Fe(II)-dependent dioxygenase that was able to convert 1 to 1b independently. A mechanism that the 5/7/6-membered carbon framework arises from prototypical 6/8/6-type taxane skeleton via radical rearrangement was proposed based on DFT calculations. More importantly, we artificially reconstructed the biosynthetic pathway of two important taxanes, baccatin IV, and baccatin VI, from GGPP in tobacco system. This work not only fully characterizes the role of C1β-hydroxylase of taxoids, but also offered new insights into the formation of taxane structural diversity.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"49 1","pages":"e202517041"},"PeriodicalIF":16.6,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Tailoring Na⁺ Chelation Dynamics for Expedient Sulfur Redox Kinetics in Low-Temperature Sodium-Sulfur Batteries. 定制Na +螯合动力学用于低温钠硫电池中有利的硫氧化还原动力学。

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202517612

Min-Hao Pai,Arumugam Manthiram

{"title":"Tailoring Na⁺ Chelation Dynamics for Expedient Sulfur Redox Kinetics in Low-Temperature Sodium-Sulfur Batteries.","authors":"Min-Hao Pai,Arumugam Manthiram","doi":"10.1002/anie.202517612","DOIUrl":"https://doi.org/10.1002/anie.202517612","url":null,"abstract":"Sodium-sulfur (Na-S) batteries have attracted considerable attention due to their high theoretical energy density and the abundant natural availability of sodium and sulfur. However, sluggish kinetics of sulfur conversion, slow Na⁺ transport, and interfacial instability at low temperatures pose significant challenges for their operation and limit their practical application. Herein, three solvents with well-designed molecular configurations are examined. We systematically investigate the impact of chelation effect on the desolvation behavior, sulfur conversion process, ion dynamics, and Na⁺ plating/stripping behavior. Compared with conventional linear ether solvents, the incorporation of methyl groups not only weaken the chelation capability and tailors the inner solvation sheath, but also reduces the energy barrier for Na⁺ transport, thus promoting enhanced sulfur conversion kinetics under low temperature conditions. This work elucidates the relationship among solvent molecules, Na⁺ desolvation behavior, and sulfur reaction kinetics, and offers a strategy for rational design of electrolytes for low-temperature metal-sulfur batteries.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"39 1","pages":"e202517612"},"PeriodicalIF":16.6,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stereoselective Synthesis of Alkenyl Fluorides and Alkynes by Defluoro Coupling of Trifluoromethyl Arenes. 三氟甲基芳烃脱氟偶联立体选择性合成氟烯基和炔烃。

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202515710

José L Rosario-Collazo,Courtney Westlund,Hawa Keita,Simon J Meek

引用次数: 0

Pd─N4 Sites in MOFs Modulate Oxygen Reduction Pathways for 100% Selective Photocatalytic CO2-to-CH4 Conversion from Oxygenated Flue Gas. MOFs中的Pd─N4位点调节氧化烟气中100%选择性光催化co2到ch4转化的氧还原途径

IF 16.6 1区化学

Angewandte Chemie International Edition Pub Date : 2025-10-20 DOI: 10.1002/anie.202513157

Wei-Hao Bai,Qi Shao,Ye-Kun Ji,Hao Dong,Xue-Yu Hu,Hao-Ran Xiao,Chao Long

{"title":"Pd─N4 Sites in MOFs Modulate Oxygen Reduction Pathways for 100% Selective Photocatalytic CO2-to-CH4 Conversion from Oxygenated Flue Gas.","authors":"Wei-Hao Bai,Qi Shao,Ye-Kun Ji,Hao Dong,Xue-Yu Hu,Hao-Ran Xiao,Chao Long","doi":"10.1002/anie.202513157","DOIUrl":"https://doi.org/10.1002/anie.202513157","url":null,"abstract":"Direct photocatalytic CO2 reduction in flue gas is significantly challenged by the thermodynamically favored oxygen reduction reaction. While conventional approaches showed promise, the inherent O2 affinity of transition and noble metals prevented full suppression of O2 adsorption and activation, severely constraining the multi-step proton-coupled electron transfers required for the CO2-to-CH4 pathway. We therefore envisioned a CO-mediated oxygen scavenging mechanism by modulating oxygen reduction pathways. Via Pd─N4 site engineering, the resulting Pd/Cu3(HITP)2/TiO2 composite effectively suppressed competitive oxygen reduction reaction, enabling selective CO2-to-CH4 conversion under aerobic conditions. Control experiments and density functional theory calculations revealed that the Pd─N4 sites steered oxygen reduction toward CO-mediated pathways-thermodynamically and kinetically favored over conventional oxygen reduction reaction, thereby mitigating competitive effects and simultaneously purifying the product. Consequently, such composite exhibited complete CH4 selectivity at 6.7 µmol g-1 h-1 under simulated industrial flue gas conditions (15 vol% CO2, 3 vol% O2, 5 vol% H2O, balanced N2). Our work highlights catalytic site modulation and advances a new strategy for photocatalytic CO2 reduction in oxygenated flue gas via pathway-selective oxygen reduction.","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":"59 1","pages":"e202513157"},"PeriodicalIF":16.6,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145331963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0