期刊文献+
共找到376篇文章
< 1 2 19 >
每页显示 20 50 100
Kangfuxin solution alleviates esophageal stenosis after endoscopic submucosal dissection:A natural ingredient strategy 被引量:2
1
作者 xin zhou Dan Ma +7 位作者 Yi-Xiang He Jing Jin Hong-Lian Wang Yun-Feng Wang Fan Yang Jian-Qin Liu Jie Chen Zhi Li 《World Journal of Gastroenterology》 SCIE CAS 2025年第1期110-125,共16页
BACKGROUND Esophageal stricture ranks among the most significant complications following endoscopic submucosal dissection(ESD).Excessive fibrotic repair is a typical pathological feature leading to stenosis after ESD.... BACKGROUND Esophageal stricture ranks among the most significant complications following endoscopic submucosal dissection(ESD).Excessive fibrotic repair is a typical pathological feature leading to stenosis after ESD.AIM To examine the effectiveness and underlying mechanism of Kangfuxin solution(KFX)in mitigating excessive fibrotic repair of the esophagus post-ESD.METHODS Pigs received KFX at 0.74 mL/kg/d for 21 days after esophageal full circumferential ESD.Endoscopic examinations occurred on days 7 and 21 post-ESD.In vitro,recombinant transforming growth factor(TGF)-β1(5 ng/mL)induced a fibrotic microenvironment in primary esophageal fibroblasts(pEsF).After 24 hours of KFX treatment(at 1.5%,1%,and 0.5%),expression ofα-smooth muscle actin-2(ACTA2),fibronectin(FN),and type collagen I was assessed.Profibrotic signaling was analyzed,including TGF-β1,Smad2/3,and phosphor-smad2/3(p-Smad2/3).RESULTS Compared to the Control group,the groups treated with KFX and prednisolone exhibited reduced esophageal stenosis,lower weight loss rates,and improved food tolerance 21 d after ESD.After treatment,Masson staining revealed thinner and less dense collagen fibers in the submucosal layer.Additionally,the expression of fibrotic effector molecules was notably inhibited.Mechanistically,KFX downregulated the transduction levels of fibrotic functional molecules such as TGF-β1,Smad2/3,and p-Smad2/3.In vitro,pEsF exposed to TGF-β1-induced fibrotic microenvironment displayed increased fibrotic activity,which was reversed by KFX treatment,leading to reduced activation of ACTA2,FN,and collagen I.The 1.5%KFX treatment group showed decreased expression of p-Smad 2/3 in TGF-β1-activated pEsF.CONCLUSION KFX showed promise as a therapeutic option for post-full circumferential esophageal ESD strictures,potentially by suppressing fibroblast fibrotic activity through modulation of the TGF-β1/Smads signaling pathway. 展开更多
关键词 Kangfuxin solution Natural component Endoscopic submucosal dissection Esophagus stricture Fibrosis
暂未订购
智能可视化重铬酸钾回流法测定化学需氧量
2
作者 周跃明 邱新 +6 位作者 周馨 万潇天 张末凡 李丰 邵鑫鑫 丁鹏 梁喜珍 《大学化学》 2026年第1期85-94,共10页
重铬酸钾回流法测定化学需氧量是水环境质量监测标准方法(HJ 828-2017)。该方法危险性强、成本高且排污严重,限制了其在化学基础实验教学中的推广应用。用色敏摄像机采集溶液反应图像,Python中的OpenCV库获取RGB数据,结合机器学习聚类分... 重铬酸钾回流法测定化学需氧量是水环境质量监测标准方法(HJ 828-2017)。该方法危险性强、成本高且排污严重,限制了其在化学基础实验教学中的推广应用。用色敏摄像机采集溶液反应图像,Python中的OpenCV库获取RGB数据,结合机器学习聚类分析,实现加热回流与滴定过程的自动化监测。将数字孪生可视化技术创新性地融入重铬酸钾回流法测化学需氧量实验中,交互式操作提升了仿真实验教学效果。 展开更多
关键词 数字孪生 重铬酸钾回流法 化学需氧量 机器学习 自动化监测
在线阅读 下载PDF
Integrative bulk and single-cell transcriptome analyses reveal RNA modification-related biomarkers of spinal cord injury
3
作者 Shixue Huang Kun Jiao +5 位作者 Keqing Li Jiayan Yuan Haoming Shu Yinuo Zhang xin zhou Xuhui zhou 《Neural Regeneration Research》 2026年第7期3249-3266,共18页
Aberrant RNA modification has been linked to the pathogenesis of various diseases;however,its specific molecular mechanisms in spinal cord injury remain poorly understood.The objective of this study was to explore RNA... Aberrant RNA modification has been linked to the pathogenesis of various diseases;however,its specific molecular mechanisms in spinal cord injury remain poorly understood.The objective of this study was to explore RNA modification-related biomarkers of spinal cord injury.The mRNA expression profiles of mice with spinal cord injury were retrieved from the Gene Expression Omnibus(GEO)database(GSE18179).We identified 185 differentially expressed genes using bioinformatics approaches.Functional enrichment analysis demonstrated aberrant activation or inhibition of common metabolism-related pathways,including sulfur metabolism and steroid biosynthesis,in mice with spinal cord injury.An integrated strategy comprising weighted gene co-expression network analysis,a random forest model,a support vector machine model,and a generalized linear model was employed to identify four genes whose aberrant RNA modification was linked to spinal cord injury:Elovl6,Idi1,Sqle,and Stbd1.We verified the expression levels and diagnostic performance of these four genes in the original training dataset and mouse samples via receiver operating characteristic curve analysis.Quantitative reverse transcription-polymerase chain reaction demonstrated variations in the mRNA levels of the four genes between the Sham and spinal cord injury groups at different time points following injury.We also constructed microRNA-mRNA and transcription factor-mRNA interaction networks using Cytoscape.Additionally,we evaluated the proportions of 22 types of immune cells in the spinal cords of mice using the CIBERSORT tool,revealing significant alterations in the numbers of memory B cells,resting dendritic cells,M0 macrophages,activated mast cells,resting mast cells,and CD8+T cells in spinal cord injury mice compared with Sham controls.Microglia and T cells were identified as key cell types by single-cell sequencing analysis.These findings provide new directions for the development of RNA modification-related therapeutic strategies for spinal cord injury and suggest that Elovl6,Idi1,Sqle,and Stbd1 are potential biomarkers of spinal cord injury. 展开更多
关键词 biomarkers machine learning microRNA-mRNA(miRNA-mRNA)network RNA sequencing RNA modification single-cell sequencing analysis spinal cord injury transcription factor-mRNA network weighted gene co-expression network analysis
暂未订购
A comprehensive review on oxygen vacancies modified catalysts:Synthesis,characterization,and crucial role in catalytic ozonation
4
作者 Fengchen Wang Yujia Xiang +9 位作者 Yuqi Zhang xin zhou Jing Zhang Chuanshu He Heng Zhang Zhaokun Xiong Peng zhou Hongyu zhou Yang Liu Bo Lai 《Chinese Chemical Letters》 2026年第2期253-262,共10页
Among various advanced oxidation processes(AOPs),heterogeneous catalytic ozonation has garnered extensive attention in wastewater treatment owing to its broad pH range applicability and the elimination of the need for... Among various advanced oxidation processes(AOPs),heterogeneous catalytic ozonation has garnered extensive attention in wastewater treatment owing to its broad pH range applicability and the elimination of the need for additional energy input.Enhancing catalyst activity by introducing oxygen vacancies has been used extensively in heterogeneous catalytic ozonation.This paper reviews prevalent methods for the construction and characterization of oxygen vacancies.Based on a thorough examination of existing research,the role of oxygen vacancies is categorized according to their primary mechanisms of action in heterogeneous catalytic ozonation.For example,modulation of the catalyst electronic structure to enhance electron transfer;participation in the reaction as an active site to generate radicals and non-radicals;and exposure of more metal sites to enhance the reaction.Lastly,the paper delineates the limitations and future research directions concerning the role of oxygen vacancies in catalytic ozonation.This review addresses the gap in existing literature concerning the role of oxygen vacancies in catalytic ozone systems,establishes a comprehensive theoretical framework to aid in the design of efficient ozone catalysts,and delves into the functionality of oxygen vacancies in heterogeneous catalytic ozone reactions. 展开更多
关键词 Catalytic ozonation Bulk defects Surface defects Oxygen vacancies Degradation mechanism Synthesis and characterization
原文传递
Protamine-1 encoded recombinant adeno-associated virus for enhanced brain magnetic resonance imaging
5
作者 Kairu Xie Yaping Yuan +3 位作者 Mou Jiang Daiqin Chen Shizhen Chen xin zhou 《Magnetic Resonance Letters》 2026年第1期25-31,共7页
Magnetic resonance imaging(MRI)is a powerful tool for diagnosing and monitoring brain diseases,but its low sensitivity can hinder early detection.To address this challenge,we utilized chemical exchange saturation tran... Magnetic resonance imaging(MRI)is a powerful tool for diagnosing and monitoring brain diseases,but its low sensitivity can hinder early detection.To address this challenge,we utilized chemical exchange saturation transfer(CEST)MRI,which greatly enhances sensitivity for detecting low-concentration compounds.In this study,we developed a CEST contrast agent based on a recombinant adeno-associated viruses(rAAVs)encoding the protamine-1(PRM1)MRI reporter gene.CEST MRI revealed that PRM1 contrast agent effectively highlighted caudate putamen region after injection of the rAAVs into the mouse brain,clearly distinguishing it from the surrounding tissue,with no observable damage.This method provides a sensitive,metal-free CEST contrast agent for in vivo brain cell detection,demonstrating potential for both diagnostic and therapeutic applications in brain diseases. 展开更多
关键词 Magnetic resonance imaging(MRI) Chemical exchange saturation transfer (CEST) Protamine 1(PRM1) Recombinant adeno-associated virus (rAAVs)
暂未订购
Detection of vitreoretinal interface abnormalities from OCT images based on DS-YOLOv7 network
6
作者 xin zhou Ying Fan +6 位作者 Gaowei Li Menghan Li Weifang Zhu Dehui Xiang xinjian Chen Xun Xu Fei Shi 《Journal of Innovative Optical Health Sciences》 2026年第2期102-115,共14页
Advances in optical coherence tomography(OCT)technology allow a clear view of the vitreoretinal interface(VRI).The abnormality of the VRI is one of the common symptoms of high myopia,mainly including posterior vitreou... Advances in optical coherence tomography(OCT)technology allow a clear view of the vitreoretinal interface(VRI).The abnormality of the VRI is one of the common symptoms of high myopia,mainly including posterior vitreous detachment(PVD)and epiretinal membrane(ERM).They can cause severe damage to the structure and function of the retina,leading to permanent vision loss.Therefore,fully automated detection of abnormalities at the VRI is crucial for the management of high myopia.This paper presents a DS-YOLOv7 network aimed at accurately identifying abnormalities,including partial PVD,complete PVD,and ERM from retinal OCT images.Built upon the YOLOv7 network,the proposed model integrates the advanced dynamic snake convolution(DSConv)module to capture the curvilinear characteristics of lesions,and the mixture of attention and convolution(ACMix)module to improve the precision and robustness of feature extraction through effective fusion of self-attention mechanisms and convolution.Moreover,the introduction of the efficient complete intersection-over-union(ECIoU)loss function further enhances the coordinate regression capability of the model.Threefold cross-validation on a dataset with 1973 OCT B-scans from 46 patients shows that the DS-YOLOv7 achieved superior performance in vitreoretinal interface abnormality detection,with mAP@0.5 of 0.714,mAP@0.75 of 0.438,and mAP@0.5:0.95 of 0.424.The proposed model can provide an accurate and efficient diagnostic tool for patients with high myopia. 展开更多
关键词 YOLOv7 dynamic snake convolution mixture of attention and convolution optical coherence tomography vitreoretinal interface abnormality
原文传递
Stratospheric transport and residence time of Hunga volcanic aerosol
7
作者 Qing Zhao xin zhou 《Earth and Planetary Physics》 2026年第1期167-175,共9页
The January 2022 eruption of Hunga injected unprecedented volumes of water vapor(150 Tg)and modest sulfur dioxide(SO_(2))into the stratosphere,producing accelerated sulfate aerosol formation in the early plume.As the ... The January 2022 eruption of Hunga injected unprecedented volumes of water vapor(150 Tg)and modest sulfur dioxide(SO_(2))into the stratosphere,producing accelerated sulfate aerosol formation in the early plume.As the aerosols gradually spread into the global stratosphere,the role of water vapor,among other factors in the spread and residence time of the sulfate aerosols,remained unclear.We used multisatellite observations to better understand the role of water vapor in the spread and lifetime of Hunga volcanic aerosols.Stratospheric circulation transported the plumes to~26 km within the polar vortices-the Antarctic by August 2022 and the Arctic by January 2023-with the arrival of aerosols lagging behind that of water vapor by months.Even though high injection altitudes(58 km)and strong Brewer-Dobson circulation contributed to prolonging the residence time of aerosols,the water vapor enhanced particle growth and thus accelerated gravitational settling,with the half lifetime of aerosols being 14 months.Our analysis revealed a critical trade-off:after the eruption of the Hunga volcano,an extremely high injection height and strong upward motion slowed the removal of aerosols,but extreme water vapor loading still had a certain impact on the half lifetime of the aerosols.These findings highlight the role of water vapor in the persistence of aerosols from submarine eruptions. 展开更多
关键词 STRATOSPHERE water vapor aerosol lifetime volcanic activity
在线阅读 下载PDF
Approach on enhancing the air conditioning system to improve the winter thermal environment in Eastern China Region's airport terminals
8
作者 Pengyu Yan Fei Yu +5 位作者 Shenyi Cui Jianjie Ma Zepeng Zhu Yun Cai xin zhou Chanjuan Sun 《Energy and Built Environment》 2026年第1期239-252,共14页
Passengers typically spend much time in commercial zones of terminals for retail,meals,and other services.Enhancing the study of thermal comfort in this local space is necessary.The climate in the Eastern China Region... Passengers typically spend much time in commercial zones of terminals for retail,meals,and other services.Enhancing the study of thermal comfort in this local space is necessary.The climate in the Eastern China Region is variable and complex,making it more challenging to maintain the indoor thermal environment.This study conducted field measurements in winter in a commercial zone of one terminal to assess the thermal environment.Numerical simulations and PMV-PPD analyses were performed using the Computational Fluid Dynamics(CFD)program The results showed that the overall humidity in the commercial zone was low.There were notable differences in the temperatures and velocities of supply air among different air vents on the commercial island.Based on these initial conditions obtained by measurements,the simulations showed that localized areas under the breathing plane are either too hot(24℃and above)or too cold(18℃and below).The dissatisfaction percentage of the population exceeds 27%.This paper proposed that through enhancements in the air vent dimensions,layout,and air supply conditions,the temperature can be maintained in the range of 20-24℃.Furthermore,the PMV could be controlled within the range of-0.5 to 0.5.PPD was below 10%,reflecting compliance with Class I heating standards.Overall,findings from this study provide a less costly modification for thermal comfort improvement in commercial zones,and serve as a reference for the design and operation of air-conditioning systems to ensure thermal comfort in airport terminals’commercial zones. 展开更多
关键词 Terminal building Field measurement Numerical simulation Thermal comfort
在线阅读 下载PDF
Virtual QPU:A Novel Implementation of Quantum Computing
9
作者 Danyang Zheng Jinchen Xv +1 位作者 xin zhou Zheng Shan 《Computers, Materials & Continua》 2026年第4期1008-1029,共22页
The increasing popularity of quantum computing has resulted in a considerable rise in demand for cloud quantum computing usage in recent years.Nevertheless,the rapid surge in demand for cloud-based quantum computing r... The increasing popularity of quantum computing has resulted in a considerable rise in demand for cloud quantum computing usage in recent years.Nevertheless,the rapid surge in demand for cloud-based quantum computing resources has led to a scarcity.In order to meet the needs of an increasing number of researchers,it is imperative to facilitate efficient and flexible access to computing resources in a cloud environment.In this paper,we propose a novel quantum computing paradigm,Virtual QPU(VQPU),which addresses this issue and enhances quantum cloud throughput with guaranteed circuit fidelity.The proposal introduces three innovative concepts:(1)The integration of virtualization technology into the field of quantum computing to enhance quantum cloud throughput.(2)The introduction of an asynchronous execution of circuits methodology to improve quantum computing flexibility.(3)The development of a virtual QPU allocation scheme for quantum tasks in a cloud environment to improve circuit fidelity.The concepts have been validated through the utilization of a self-built simulated quantum cloud platform. 展开更多
关键词 Quantum computing scheduling parallel computing computational paradigm
在线阅读 下载PDF
S型ZnO/CdIn_(2)S_(4)光催化剂制备H_(2)O_(2)偶联苄胺氧化的超快电子转移飞秒吸收光谱研究
10
作者 杨祎 周欣 +3 位作者 谷苗莉 程蓓 吴珍 张建军 《物理化学学报》 北大核心 2025年第6期91-102,共12页
光催化合成过氧化氢(H_(2)O_(2))是一种至关重要的清洁能源转化过程,涉及对氧气的两电子还原。然而,这一过程常常受限于缓慢的水氧化反应,后者需要光生空穴的参与。为了应对此挑战,我们设计了一种双功能的S型ZnO/CdIn_(2)S_(4)异质结体... 光催化合成过氧化氢(H_(2)O_(2))是一种至关重要的清洁能源转化过程,涉及对氧气的两电子还原。然而,这一过程常常受限于缓慢的水氧化反应,后者需要光生空穴的参与。为了应对此挑战,我们设计了一种双功能的S型ZnO/CdIn_(2)S_(4)异质结体系,将H_(2)O_(2)生成与增值的苄胺(BA)氧化反应进行耦合。在此双功能光催化系统中,CdIn_(2)S_(4)中的光生电子可以高效地还原O2生成H_(2)O_(2),而ZnO中的光生空穴则选择性地将BA氧化为N-亚苄基苄胺。得益于S型异质结的优势,相比于纯ZnO或CdIn_(2)S_(4),优化后的ZnO/CdIn_(2)S_(4)光催化剂展示出显著更高的H_(2)O_(2)生成速率(386μmol·L^(-1)·h^(-1))和BA转化率(81%)。飞秒瞬态吸收光谱(fs-TA)结果说明,ZnO/CdIn_(2)S_(4)复合材料在光的激发下,在ZnO导带(CB)和CdIn_(2)S_(4)价带(VB)之间发生超快S型电子转移。此外,ZnO的VB空穴和CdIn_(2)S_(4)的CB电子的及时消耗,有助于加速ZnO/CdIn_(2)S_(4)S型异质结界面中的电荷转移。本文中ZnO/CdIn_(2)S_(4)S型光催化体系的创新设计为高效的双功能异质结光催化系统的开发提供了新的思路,并引入了一种利用fs-TA光谱研究S型异质结的新方法。 展开更多
关键词 光催化产H_(2)O_(2) S型异质结 选择性苄胺氧化 fs-TA光谱 电子转移动力学
在线阅读 下载PDF
利用飞秒瞬态吸收光谱研究pH值对质子化COF光催化H_(2)O_(2)生成的影响
11
作者 周欣 霍怡廷 +4 位作者 杨松瑀 何博文 王晓晶 吴珍 张建军 《物理化学学报》 北大核心 2025年第12期122-133,共12页
共价有机框架材料(COFs)因其结构可精确调控且具有高比表面积,被认为是极具前景的过氧化氢(H_(2)O_(2))光催化合成材料。然而,pH值对COFs在光催化合成H_(2)O_(2)过程中稳定性的关键影响尚不明确。本研究通过简单质子化策略显著提升了亚... 共价有机框架材料(COFs)因其结构可精确调控且具有高比表面积,被认为是极具前景的过氧化氢(H_(2)O_(2))光催化合成材料。然而,pH值对COFs在光催化合成H_(2)O_(2)过程中稳定性的关键影响尚不明确。本研究通过简单质子化策略显著提升了亚胺连接型COF的光催化H_(2)O_(2)合成性能。值得注意的是,质子化COF在弱酸性条件(pH≥3)下表现出优异的稳定性,但在强酸性条件(pH<3)下会发生不可逆水解。质子化过程发生在亚胺单元的氮原子上,具有双重功能:抑制超快电荷复合(由飞秒瞬态吸收光谱证实)以及直接为H_(2)O_(2)生成提供质子源。此外,在光催化体系中引入氟离子(F-)可进一步提高H_(2)O_(2)产率,F-的强电负性促进了电子从COF向F-转移,从而实现光生载流子的空间分离。机理研究证实H_(2)O_(2)通过双电子氧还原反应路径生成。这些发现阐明了质子化COFs的pH依赖性稳定性与活性,为载流子转移动力学提供了思路,并为开发高效稳定的COF基光催化剂用于太阳能驱动H_(2)O_(2)合成确立了设计原则。 展开更多
关键词 共价有机框架 结构稳定性 质子化 氟离子表面修饰 飞秒瞬态吸收光谱
在线阅读 下载PDF
TiO_(2)/CdS S型异质结促进光催化CO_(2)甲烷化及其飞秒瞬态吸收光谱机理研究
12
作者 霍怡廷 周欣 +4 位作者 赵非凡 艾陈斌 吴珍 常志东 朱必成 《物理化学学报》 北大核心 2025年第11期120-132,共13页
通过光催化将CO_(2)转化为高附加值碳氢化合物在可持续能源领域具有巨大潜力,但实现高活性和选择性仍然具有挑战性。本文中,一种新型的TiO_(2)/CdS异质结光催化剂在光催化CO_(2)还原中表现出优异的性能。优化后的催化剂的CH_(4)产率比纯... 通过光催化将CO_(2)转化为高附加值碳氢化合物在可持续能源领域具有巨大潜力,但实现高活性和选择性仍然具有挑战性。本文中,一种新型的TiO_(2)/CdS异质结光催化剂在光催化CO_(2)还原中表现出优异的性能。优化后的催化剂的CH_(4)产率比纯TiO_(2)提高了4.2倍,且对CH_(4)的选择性高达65.4%(CO为34.6%)。其增强的活性源于独特的形貌,促进了CO_(2)的吸附和传质,以及CdS与TiO_(2)之间形成紧密的S型异质结,这提高了电荷分离效率,同时保持了强氧化还原电位。并且,飞秒瞬态吸收光谱(fs-TAS)与原位漫反射红外傅里叶变换光谱(DRIFTS)相结合,为光催化二氧化碳还原路径提供了直接证据,并确定了CdS上的硫位点是稳定^(*)CH_(3)O、^(*)CHO和^(*)CO中间体的关键,从而促进选择性生成CH_(4)。此外,基于密度泛函理论(DFT)的理论计算进一步补充了实验结果。计算证实了S型异质结的电子结构特征,揭示了原子尺度上的能级和电荷转移机制。这不仅加深了我们对光催化过程的理解,还为进一步优化光催化剂设计提供了理论基础。总体而言,我们的工作展示了TiO_(2)/CdS异质结光催化剂在光催化CO_(2)还原中的优异性能。 展开更多
关键词 光催化CO_(2)还原 甲烷选择性 fs-TAS S型异质结
在线阅读 下载PDF
Medium-entropy configuration enabling reversible P2-OP4 phase transition in layered oxides for high-rate sodium-ion batteries 被引量:2
13
作者 Fei-Fei Hong xin zhou +9 位作者 Hao Liu Gui-Lin Feng Xiao-Hong Liu Heng Zhang Wei-Feng Fan Bin Zhang Mei-Hua Zuo Wang-Yan xing Ping Zhang Wei Xiang 《Rare Metals》 2025年第5期2997-3007,共11页
Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+d... Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials. 展开更多
关键词 Layered oxide cathode Sodium ion batteries Phase transition Medium-entropy P2/O3 biphasic structure
原文传递
Expert consensus on early orthodontic treatment of class Ⅲ malocclusion 被引量:1
14
作者 xin zhou Si Chen +30 位作者 Chenchen zhou Zuolin Jin Hong He Yuxing Bai Weiran Li Jun Wang Min Hu Yang Cao Yuehua Liu Bin Yan Jiejun Shi Jie Guo Zhihua Li Wensheng Ma Yi Liu Huang Li Yanqin Lu Liling Ren Rui Zou Linyu Xu Jiangtian Hu Xiuping Wu Shuxia Cui Lulu Xu Xudong Wang Songsong Zhu Li Hu Qingming Tang Jinlin Song Bing Fang Lili Chen 《International Journal of Oral Science》 2025年第3期328-340,共13页
The prevalence of Class Ⅲ malocclusion varies among different countries and regions. The populations from Southeast Asian countries (Chinese and Malaysian) showed the highest prevalence rate of 15.8%, which can serio... The prevalence of Class Ⅲ malocclusion varies among different countries and regions. The populations from Southeast Asian countries (Chinese and Malaysian) showed the highest prevalence rate of 15.8%, which can seriously affect oral function, facial appearance, and mental health. As anterior crossbite tends to worsen with growth, early orthodontic treatment can harness growth potential to normalize maxillofacial development or reduce skeletal malformation severity, thereby reducing the difficulty and shortening the treatment cycle of later-stage treatment. This is beneficial for the physical and mental growth of children. Therefore,early orthodontic treatment for Class Ⅲ malocclusion is particularly important. Determining the optimal timing for early orthodontic treatment requires a comprehensive assessment of clinical manifestations, dental age, and skeletal age, and can lead to better results with less effort. Currently, standardized treatment guidelines for early orthodontic treatment of Class Ⅲ malocclusion are lacking. This review provides a comprehensive summary of the etiology, clinical manifestations, classification, and early orthodontic techniques for Class Ⅲ malocclusion, along with systematic discussions on selecting early treatment plans. The purpose of this expert consensus is to standardize clinical practices and improve the treatment outcomes of Class Ⅲ malocclusion through early orthodontic treatment. 展开更多
关键词 reducing difficulty shortening trea normalize maxillofacial development Early orthodontic treatment Southeast Asian countries ClassⅢmalocclusion orthodontic treatment Prevalence reduce skeletal malformation severitythereby
暂未订购
Promoting densification and strengthening effect of ultrasonic impact treatment on Haynes 230 alloy manufactured by laser powder bed fusion 被引量:1
15
作者 Wenjie Liu Hui Li +1 位作者 Qianxing Yin xin zhou 《Journal of Materials Science & Technology》 2025年第13期226-240,共15页
Laser powder bed fusion(LPBF)has been extensively investigated owing to its high geometry formation accuracy and excellent mechanical properties.However,the LPBFed Haynes 230 parts typically display poor tensile and w... Laser powder bed fusion(LPBF)has been extensively investigated owing to its high geometry formation accuracy and excellent mechanical properties.However,the LPBFed Haynes 230 parts typically display poor tensile and wear properties due to internal porosity.In this work,the ultrasonic impact treatment(UIT)was applied as a post-treatment to the LPBFed Haynes 230 alloy,porosity and microstructure mod-ulation were performed to improve the strength properties and wear resistance.The pore closure and mi-crostructure were studied by numerical simulations and experiments,and the mechanisms of increasing densification and strength were discussed.Results show that UIT can effectively close pores and reduce porosity,the internal porosity of the ultrasonic impacted layer for one,two,and three times decreases by 63.6%,70.9%,and 81.8%,respectively.Pore closure is attributed to the residual compressive stress and shear stress introduced by UIT.Besides,the UIT weakened texture strength and refined grains,especially promoting the formation of fine grains.Meanwhile,it also promotes the formation of a high disloca-tion density and improves the phase structure distribution.Furthermore,the ultimate tensile and yield strengths of the optimal impact process increased by 9.6%and 34.6%,respectively.The improvement in strength was attributed to dislocation,grain boundary,and promoting densification strengthening.The average friction coefficient reduces by 4.9%-14.6%by refining the surface grains and increasing dislo-cation density.This work has verified the feasibility of improving the mechanical properties and pore closure of the LPBFed Haynes 230 alloy by UIT. 展开更多
关键词 Laser powder bed fusion Haynes 230 alloy Ultrasonic impact treatment MICROSTRUCTURE Mechanical properties Wear properties
原文传递
High-throughput additive manufacturing and characterization of CoCrFeNi-AlTi high-entropy alloys 被引量:1
16
作者 Xiu-Xiu Lv Wen-Tao Liu +7 位作者 Jia-Qi Li Lian-zhou Li Cai-Xia Wang Hua Zhang xin zhou Liang Jiang Jing-Jing Ruan Li-Long Zhu 《Rare Metals》 2025年第3期1943-1957,共15页
Co-precipitation strengthening of the L1_(2)nano-particles along with hard intermetallic phases,including L2_(1),B2,σandη,demonstrates significant potential for the development of advanced CoCrFeNi high-entropy allo... Co-precipitation strengthening of the L1_(2)nano-particles along with hard intermetallic phases,including L2_(1),B2,σandη,demonstrates significant potential for the development of advanced CoCrFeNi high-entropy alloys(HEAs)with favorable strength-ductility balances.Understanding the alloying effect of Al and Ti on the formation and stability of these intermetallic phases in the CoCrFeNi HEAs is crucial for efficiently exploring the multi-component space for future alloy designs.In the present work,stepwise compositionally graded CoCrFeNi-AlTi HEAs comprising 35 different compositions were fabricated using high-throughput additive manufacturing(AM)and analyzed through a suite of localized characterization techniques.Our analysis confirmed the existence of two primary solid solution phases,face-centered cubic(FCC)and body-centered cubic(BCC),as well as four distinct intermetallic phases,which include L1_(2),L2_(1),σandη.By overlapping the zero phase fraction(ZPF)lines of these phases,the pseudo-ternary phase diagram of the multi-component CoCrFeNi-AlTi system at 800℃was determined,demonstrating good agreement with the literature results.Furthermore,the composition-dependent microstructural evolution and Vickers hardness(HV)were also established,providing numerous opportunities to design CoCrFeNi-AlTi HEAs with superior microstructure stability and balanced strength-ductility properties for structural applications at elevated temperatures. 展开更多
关键词 High-entropy alloys Additive manufacturing Multi-component phase equilibria MICROSTRUCTURE Precipitation strengthening Vickers hardness
原文传递
The increasing predominance of extreme precipitation in Southwest China since the late 1970s 被引量:6
17
作者 Guowei Zheng Yang Li +4 位作者 Quanliang Chen xin zhou Guolu Gao Minggang Li Ting Duan 《Atmospheric and Oceanic Science Letters》 CSCD 2022年第5期43-48,共6页
Extreme precipitation events cause severe environmental and societal damage worldwide.Southwest China(SWC)is sensitive to such effects because of its overpopulation,underdevelopment,and fragile ecosystems.Using daily ... Extreme precipitation events cause severe environmental and societal damage worldwide.Southwest China(SWC)is sensitive to such effects because of its overpopulation,underdevelopment,and fragile ecosystems.Using daily observations from 108 rain-gauge stations,the authors investigated the frequency of extreme precipitation events and their contribution to total precipitation in SWC since the late 1970 s.Results indicate that total precipitation is decreasing insignificantly,but rainfall-events frequency is decreasing significantly,whereas the region is experiencing more frequent and intense extreme precipitation events.Note that although fewer stations are statistically significant,about 60%of the rain-gauge stations show an increasing trend in the frequency and intensity of extreme precipitation.Furthermore,there is an increasing trend in the contribution of total extreme precipitation to total precipitation,with extreme precipitation becoming dominant in the increasingly arid SWC region.The results carry important implications for policymakers,who should place greater emphasis on extreme precipitation and associated floods and landslides when drafting water-resource management policies. 展开更多
关键词 Extreme precipitation Southwest China TREND Frequency Intensity
在线阅读 下载PDF
锂金属电池中的氟代功能电解液
18
作者 傅云鹏 陈王磊 +2 位作者 周鑫 王央 汪靖伦 《化学进展》 北大核心 2025年第6期934-948,共15页
锂金属电池由于其较高的能量密度而受到广泛的关注,但安全性和循环稳定性等问题成为限制其发展的重要原因。电解液是锂金属电池不可缺少的组成部分,发展高效的电解液体系是解决锂金属电池问题的有效手段和策略。由于氟原子的吸电子诱导... 锂金属电池由于其较高的能量密度而受到广泛的关注,但安全性和循环稳定性等问题成为限制其发展的重要原因。电解液是锂金属电池不可缺少的组成部分,发展高效的电解液体系是解决锂金属电池问题的有效手段和策略。由于氟原子的吸电子诱导效应可降低电解液分子的最低未占据分子轨道,促进锂金属负极表面富含氟化锂的固态电解质界面层(SEI)的形成,从而增强电解液与锂金属负极的兼容性并抑制锂枝晶的生长;同时,氟原子的取代可改变电解液分子的静电势分布,从而改变分子的溶剂化结合位点,起到调控溶剂化结构的作用;此外,氟代功能化还可显著改善电解液的阻燃性和高低温性能。本文详细综述了用于锂金属电池的氟代溶剂,从氟代溶剂种类、氟代度以及氟代位置几个方面分类总结了氟代碳酸酯、氟代醚、氟代羧酸酯、氟代硅烷、氟代腈等功能分子,重点阐述氟代功能分子对电解液溶剂化结构调控、SEI组成和形成机制以及电池性能表现的影响。最后,总结和展望了氟代溶剂在锂金属电池体系中的发展前景。 展开更多
关键词 锂金属电池 电解液 氟代溶剂 溶剂化结构 固态电解质界面膜
原文传递
我国学前儿童数学监测指标体系的构建 被引量:17
19
作者 周欣 黄瑾 +6 位作者 郭力平 左志宏 李美芳 杨志艳 李莉 李琳 范洁琼 《学前教育研究》 CSSCI 北大核心 2018年第10期12-21,共10页
对儿童学习和发展结果的评估与监控是教育质量监测的重要内容。学前儿童数学监测指标体系本质上是对3~6岁儿童在与数学学习有关的知识、能力、态度、学习品质等方面的发展的较为系统的期望。在厘清21世纪创新社会对人才数学素养要求的... 对儿童学习和发展结果的评估与监控是教育质量监测的重要内容。学前儿童数学监测指标体系本质上是对3~6岁儿童在与数学学习有关的知识、能力、态度、学习品质等方面的发展的较为系统的期望。在厘清21世纪创新社会对人才数学素养要求的基础上,参考国内外研究文献和国内相关政策文件,本研究构建了学前儿童数学监测指标体系草案,然后采用德尔菲专家访谈方法,结合幼儿园教师在实践中的实际使用情况与反馈,对该指标体系进行了内容效度检验,并根据检验结果对指标体系进行了多次修改,最终确定的监测指标体系包含数学知识技能、过程性能力、态度和学习品质三个方面共20条指标,今后应进一步开发和完善与这一数学监测指标体系相匹配的注重儿童数学问题解决过程的诊断性测评工具和适合教师使用的观察评定表,以更好地发挥监测为改进教学、促进儿童发展服务的功能。 展开更多
关键词 教育质量 质量监测 儿童数学学习 发展期望
在线阅读 下载PDF
5~6岁儿童数学问题解决的认知诊断评估工具 被引量:6
20
作者 李莉 周欣 +5 位作者 涂冬波 高旭亮 黄瑾 杨志艳 李美芳 夏青 《学前教育研究》 CSSCI 北大核心 2019年第5期27-42,共16页
基于认知诊断评估理论和技术,本研究采用文献分析、专家研讨和口语报告法构建5~6岁儿童"数与运算"领域数学问题解决的认知模型,对627名5~6岁儿童进行认知诊断评估,运用认知诊断模型—数据拟合对认知模型和诊断测验进行质量... 基于认知诊断评估理论和技术,本研究采用文献分析、专家研讨和口语报告法构建5~6岁儿童"数与运算"领域数学问题解决的认知模型,对627名5~6岁儿童进行认知诊断评估,运用认知诊断模型—数据拟合对认知模型和诊断测验进行质量检验。结果显示,认知属性对题目难度的解释量为0.879,效应量为0.834,平均HCI为0.749;认知诊断测验题目的平均区分度为0.707(标准差为0.299);除两题的题目拟合度S-X^2指标的显著性水平<0.01,其他题目的拟合度都较好;测验的信度为0.95;平均掌握概率与测验总分呈单调递增曲线。以上结果说明,本研究构建的儿童数学问题解决认知模型良好,编制的认知诊断测验具有较理想的测量信度与效度,可以作为评估儿童数学问题解决的有效工具,并可以提供精细丰富的诊断信息,从而为相关教育教学及干预研究提供科学依据。 展开更多
关键词 问题解决 数与运算 认知诊断评估
在线阅读 下载PDF
上一页 1 2 19 下一页 到第
使用帮助 返回顶部