期刊文献+
共找到1,013篇文章
< 1 2 51 >
每页显示 20 50 100
Sea ice classification in the Arctic transition zone using Haiyang-2B microwave scatterometer and radiometer data
1
作者 Shiyu Wu Tingting Liu +3 位作者 Mohammed Shokr Ruibo Lei fan yang Yachao Li 《Acta Oceanologica Sinica》 2025年第3期84-101,共18页
Loss of multiyear ice(MYI)is of great importance for Arctic climate and marine systems and can be monitored using active and passive microwave satellite data.In this paper,we describe an upgraded classification algori... Loss of multiyear ice(MYI)is of great importance for Arctic climate and marine systems and can be monitored using active and passive microwave satellite data.In this paper,we describe an upgraded classification algorithm using the data from the scatterometer and radiometer sensors onboard the Chinese Haiyang-2B(HY-2B)satellite to identify MYI and first-year ice(FYI).The proposed method was established based on K-means and fuzzy clustering(K-means+FC)and was used to focus on the transition zone where the ice condition is complex due to the highly commixing of MYI and FYI,leading to the high challenge for accurate classification of sea ice.The K-means algorithm was applied to preliminarily classify MYI using the combination of scatterometer and radiometer data,followed by applying fuzzy clustering to reclassify MYI in the transition zone.The HY-2B K-means+FC results were compared with the ice type products[including the Ocean and Sea Ice Satellite Application Facility(OSI SAF)sea ice type product and the Equal-Area Scalable Earth-Grid sea ice age dataset],and showed agreement in the time series of MYI extent.Intercomparisons in the transition zone indicated that the HY-2B K-means+FC results can identify more old ice than the OSI SAF product,but with an underestimation in identifying second-year ice.Comparisons between K-means and Kmeans+FC results were performed using regional ice charts and Sentinel-1 synthetic aperture radar(SAR)data.By adding fuzzy clustering,the MYI is more consistent with the ice charts,with the overall accuracy(OA)increasing by 0.9%–6.5%.Comparing against SAR images,it is suggested that more scattered MYI floes can be identified by fuzzy clustering,and the OA is increased by about 3%in middle freezing season and 7%–20%in early and late freezing season. 展开更多
关键词 sea ice classification Arctic multiyear ice Haiyang-2B transition zone microwave remote sensing fuzzy clustering
在线阅读 下载PDF
离子键交联碳化聚合物点用于可调谐和增强的室温磷光
2
作者 康春源 李小瑜 +1 位作者 杨帆 杨柏 《物理化学学报》 北大核心 2026年第1期130-139,共10页
碳化聚合物点因其可调的发光性能和简便的合成方法,已成为有前景的室温磷光材料。然而,当前依赖氢键/共价键来增强发光的策略存在磷光强度有限和颜色多样性不足(主要为绿色)的问题。本工作提出构建离子键交联网络作为一种新颖的设计策... 碳化聚合物点因其可调的发光性能和简便的合成方法,已成为有前景的室温磷光材料。然而,当前依赖氢键/共价键来增强发光的策略存在磷光强度有限和颜色多样性不足(主要为绿色)的问题。本工作提出构建离子键交联网络作为一种新颖的设计策略来解决这些局限性。得益于离子键的高强度、无方向性和无饱和性,构建的交联网络能够固定发色团并抑制非辐射跃迁。通过将锂离子引入聚丙烯酸基碳化聚合物点中,光致发光量子产率从1.1%显著提升至48.4%,磷光强度增强了近40倍。进一步引入锌离子,通过过渡金属掺杂实现了从绿色到黄色的可调谐室温磷光发射。该策略实现了对碳化聚合物点中室温磷光强度和波长的有效调控,为设计具有定制化室温磷光特性的先进有机磷光材料提供了一个通用平台。 展开更多
关键词 碳点 碳化聚合物点 室温磷光 交联增强发射效应 离子键
在线阅读 下载PDF
Machine learning identifies key cells and therapeutic targets during ferroptosis after spinal cord injury
3
作者 Yigang Lv Zhen Li +10 位作者 Lusen Shi Huan Jian fan yang Jichuan Qiu Chao Li Peng Xiao Wendong Ruan Hao Li Xueying Li Shiqing Feng Hengxing Zhou 《Neural Regeneration Research》 2026年第6期2495-2505,共11页
Ferroptosis,a type of cell death that mainly involves iron metabolism imbalance and lipid peroxidation,is strongly correlated with the phagocytic response caused by bleeding after spinal cord injury.Thus,in this study... Ferroptosis,a type of cell death that mainly involves iron metabolism imbalance and lipid peroxidation,is strongly correlated with the phagocytic response caused by bleeding after spinal cord injury.Thus,in this study,bulk RNA sequencing data(GSE47681 and GSE5296)and single-cell RNA sequencing data(GSE162610)were acquired from gene expression databases.We then conducted differential analysis and immune infiltration analysis.Atf3 and Piezo1 were identified as key ferroptosis genes through random forest and least absolute shrinkage and selection operator algorithms.Further analysis of single-cell RNA sequencing data revealed a close relationship between ferroptosis and cell types such as macrophages/microglia and their intrinsic state transition processes.Differences in transcription factor regulation and intercellular communication networks were found in ferroptosis-related cells,confirming the high expression of Atf3 and Piezo1 in these cells.Molecular docking analysis confirmed that the proteins encoded by these genes can bind cycloheximide.In a mouse model of T8 spinal cord injury,low-dose cycloheximide treatment was found to improve neurological function,decrease levels of the pro-inflammatory cytokine inducible nitric oxide synthase,and increase levels of the anti-inflammatory cytokine arginase 1.Correspondingly,the expression of the ferroptosis-related gene Gpx4 increased in macrophages/microglia,while the expression of Acsl4 decreased.Our findings reveal the important role of ferroptosis in the treatment of spinal cord injury,identify the key cell types and genes involved in ferroptosis after spinal cord injury,and validate the efficacy of potential drug therapies,pointing to new directions in the treatment of spinal cord injury. 展开更多
关键词 bioinformatic analyses bulk-RNA sequencing cellular communication analysis ferroptosis machine learning analysis neurological function RNA velocity analysis single-cell RNA sequencing therapeutic drugs transcription factor analysis
暂未订购
Progress on Omega-3 fatty acids for the comprehensive and targeted treatment of spinal cord injury
4
作者 Zhongze Yuan Lusen Shi +15 位作者 Xiao-Na Tao Xiangchuang fan Han Zheng Yifan Shang Xiaoqing Zhao fan yang Hui Lin Peng Xiao Bo Chu Jichuan Qiu Shaohui Zong Ning Ran Xiaohong Kong Jin-Peng Sun Hengxing Zhou Shiqing Feng 《Bone Research》 2026年第1期62-81,共20页
Traumatic spinal cord injury(SCI)is a debilitating condition characterized by the impairment of neural circuits,leading to the loss of motor and sensory functions and accompanied by severe complications.Substantial re... Traumatic spinal cord injury(SCI)is a debilitating condition characterized by the impairment of neural circuits,leading to the loss of motor and sensory functions and accompanied by severe complications.Substantial research has reported the therapeutic potential of Omega-3 fatty acids for the central nervous system,particularly after traumatic SCI.Omega-3 fatty acids may contribute to improving SCI recovery through their anti-inflammatory,anti-oxidative,neurotrophic,and membrane integrity-preserving properties.These functions of Omega-3 fatty acids are primarily mediated via the activation of G protein-coupled receptor 120(GPR120),commonly known as the fish oil-specific receptor.Advancements in understanding of the molecular mechanisms of GPR120’s recognition of Omega-3 fatty acids and its downstream signaling mechanisms has significantly promoted research on the pharmacological potential of Omega-3 fatty acids and the development of highly selective and high-affinity alternatives.This review aims to provide in-depth analysis of the comprehensive therapeutic potential of Omega-3 fatty acids for SCI and its accompanying complications,and the prospects for developing novel drugs based on the recognition of Omega-3 fatty acids by GPR120. 展开更多
关键词 central nervous systemparticularly impairment neural circuitsleading spinal cord injury traumatic spinal cord injury omega fatty acids sensory functions traumatic spinal cord injury sci neural circuits
暂未订购
Interpretable and Reliable Soft Sensor Development in Industry 5.0
5
作者 Liang Cao Jianping Su +2 位作者 fan yang Yankai Cao Bhushan Gopaluni 《IEEE/CAA Journal of Automatica Sinica》 2026年第1期236-238,共3页
Dear Editor,This letter presents a new approach to developing interpretable and reliable soft sensors for Industry 5.0 applications.Although sophisticated machine learning methods have made remarkable strides in soft-... Dear Editor,This letter presents a new approach to developing interpretable and reliable soft sensors for Industry 5.0 applications.Although sophisticated machine learning methods have made remarkable strides in soft-sensor predictive accuracy,ensuring interpretability and reliable performance across varying industrial operating conditions remains a challenge[1]–[4].This is precisely what Industry 5.0,proposed by the European Commission in 2021,advocates[5],[6].It integrates various cutting-edge technologies,such as human-machine interaction,digital twins,cybersecurity and artificial intelligence,to facilitate the development of better soft sensors. 展开更多
关键词 machine learning digital twins CYBERSECURITY interpretable soft sensors soft sensors sophisticated machine learning methods INDUSTRY reliable soft sensors
在线阅读 下载PDF
Study on the strength deterioration characteristics and microscopic mechanisms of moraine soil under freeze-thaw cycles
6
作者 Peng-fei Wang Ming-li Li +3 位作者 Ming Chang Jun-lin Jiang fan yang Zhi-qiang Zuo 《Journal of Groundwater Science and Engineering》 2026年第1期15-31,共17页
To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,... To investigate the strength degradation characteristics and microscopic damage mechanisms of moraine soil under hydro-thermo-mechanical coupling conditions,a series of X-ray Diffraction(XRD),standard triaxial testing,Scanning Electron Microscopy(SEM),and Nuclear Magnetic Resonance(NMR)experiments were conducted.The mechanical property degradation laws and evolution characteristics of the microscopic pore structure of moraine soil under Freeze-Thaw(F-T)conditions were revealed.After F-T cycles,the stress-strain curves of moraine soil showed a strain-softening trend.In the early stage of F-T cycles(0–5 cycles),the shear strength and elastic modulus exhibited damage rate of approximately 10.33%±0.8%and 16.60%±1.2%,respectively.In the later stage(10–20 cycles),the strength parameters fluctuated slightly and tended to stabilize.The number of F-T cycles was negatively exponentially correlated with cohesion,while showing only slight fluctuation in the internal friction angle,thereby extending the Mohr-Coulomb strength criterion for moraine soil under F-T cycles.The NMR experiments quantitatively characterized the evolution of the internal pore structure of moraine soil under F-T cycles.As the number of F-T cycles increased,fine and micro pores gradually expanded and merged due to the frost-heaving effect during the water-ice phase transition,forming larger pores.The proportion of large and medium pores increased to 59.55%±2.1%(N=20),while that of fine and micro pores decreased to 40.45%±2.1%(N=20).The evolution of pore structure characteristics was essentially completed in the later stage of F-T cycles(10–20 cycles).This study provides a theoretical foundation and technical support for major engineering construction and disaster prevention in the Qinghai-Xizang Plateau. 展开更多
关键词 Moraine soil in the Qinghai-Xizang Plateau F-T cycle Standard triaxial tests soil strength degradation Mohr-Coulomb criterion Microscopic pore structure
在线阅读 下载PDF
Cognitive behavioral therapy enhances psychological and physiological outcomes in high-altitude respiratory patients
7
作者 De-Feng Meng Dong-You Zhang +3 位作者 fan yang Peng-Li Meng Ting-Ting Wen Yu-Zhao Wang 《World Journal of Psychiatry》 2026年第1期212-220,共9页
BACKGROUND Due to the dry and cold climate,the obvious temperature difference between day and night,and the low oxygen content of the air in the plateau area,people are prone to upper respiratory tract diseases,and of... BACKGROUND Due to the dry and cold climate,the obvious temperature difference between day and night,and the low oxygen content of the air in the plateau area,people are prone to upper respiratory tract diseases,and often the condition is prolonged,and the patients are prone to anxiety and uneasiness,which may be related to the harshness of the plateau environment,somatic discomfort due to the lack of oxygen,anxiety about the disease,and other factors.AIM To investigate the effects of cognitive behavioral therapy(CBT)on anxiety,sleep disorders,and hypoxia tolerance in patients with high-altitude respiratory diseases.METHODS A total of 2337 patients with high-altitude-related respiratory diseases treated at our hospital between November 2023 and January 2024 were selected as the study subjects.The subjects’pre-high-altitude residential altitude was approximately 1700 meters.They were divided into two groups.Both groups were given symptomatic treatment,and the control group implemented conventional nursing intervention,while the research group simultaneously conducted CBT intervention;assessed the degree of health knowledge of the two groups,and applied the Hamilton Anxiety Scale and the Pittsburgh Sleep Quality Index to assess the anxiety and sleep quality of the patients before and after the intervention,respectively.It also observed the length and efficiency of sleep,and detected the level of serum hypoxia inducible factor-1α,erythropoietin(EPO)and clinical intervention before and after intervention.EPO levels,and investigated satisfaction with the clinical intervention.RESULTS The rate of excellent health knowledge in the intervention group was 93.64%,which was higher than that in the control group(74.23%;P<0.05).Before the intervention,there was no significant difference in Hamilton Anxiety Scale and Pittsburgh Sleep Quality Index scores between the two groups(P>0.05),and after the intervention,the scores of the study group were significantly lower than those of the control group(P<0.05).There was no significant difference in sleep duration and sleep efficiency between the groups before the intervention(P>0.05),and after the intervention,the scores of the study group were significantly larger than those of the control group(P<0.05).There was no significant difference in serum hypoxia inducible factor-1αand EPO between the two groups before intervention(P>0.05),and both research groups were significantly lower than the control group after intervention(P<0.05).According to the questionnaire survey,the intervention satisfaction of the study group was 95.53%,which was higher than that of the control group(80.14%;P<0.05).CONCLUSION The CBT intervention in the treatment of patients with high-altitude-related respiratory diseases helps improve patients'health knowledge,relieve anxiety,improve sleep quality and hypoxia tolerance,and improve nursing satisfaction. 展开更多
关键词 Cognitive behavioral therapy High altitude respiratory disease ANXIETY Sleep quality Hypoxia tolerance
暂未订购
Phase-field simulation of the dendrite fragmentation by electromagnetic stirring in AA5754 aluminum alloy laser beam welding
8
作者 Chunliang yang fan yang +3 位作者 Xiangmeng Meng Stephen Nugraha Putra Marcel Bachmann Michael Rethmeier 《China Welding》 2026年第1期57-68,共12页
A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser bea... A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser beam welding.Compare the calculated results that include dendrite fragmentation caused by the thermal electromagnetic Lorentz force with the results that consider only the thermal electromagnetic Lorentz force,without fragmentation,at the characteristic time instants.Both in the early and late stages,the small fragmentation at the dendrite tip promotes the number of higher-order branches and their growth,especially in the direction perpendicular to the solidification.The later stage fragmentation has the possibility of breaking one grain into several,which verifies the possibility of grain refinement caused by dendrite fragmentation.The fracture surface caused by fragmentation also makes more solid-liquid interfaces and their growth.In addition,the cases with different initial nuclear positions were compared.The grain growth in the low-temperature zone can be inhibited by the equiaxed grains'fragmentation at the high-temperature area(179.8μm^(2) and 14.7% start at the center,115.4μm^(2) and 9.4% start at the high-temperature corner,134.3μm^(2) and 10.9%start at the low-temperature corner),which is another kind of grain refinement by the dendrite fragmentation.This kind of inhibition effect on grain growth in the low-temperature region will be enhanced with the increasing time interval between the two crystal nuclei’appearance(179.8μm^(2) and 14.7%when virtual grains appear at t=4.3803 s and t=4.3803 s,134.3μm^(2) and 10.9%at t=4.0977 s and t=3.9564 s,and 115.4μm^(2) and 9.4%at t=3.8151 s and t=3.5325 s). 展开更多
关键词 Laser beam welding ELECTROMAGNETIC Aluminum alloys Phase field method Equiaxed grain Dendrite fragmentation
在线阅读 下载PDF
Does the adoption of direct-seeded rice affect pesticide use?Evidence from China
9
作者 Chao Zhang Shanshan Li +1 位作者 fan yang Ruifa Hu 《Journal of Integrative Agriculture》 2026年第1期366-376,共11页
In China,farmers have increasingly adopted direct-seeded rice(DSR).While various impacts of DSR have been studied,limited evidence exists regarding the effect of DSR adoption on pesticide use.This study examines the i... In China,farmers have increasingly adopted direct-seeded rice(DSR).While various impacts of DSR have been studied,limited evidence exists regarding the effect of DSR adoption on pesticide use.This study examines the impact of DSR adoption on pesticide use utilizing data from a 2018 survey of 982 rice farmers in China's Yangtze River Basin.The endogenous treatment-regression and switching regression models are employed to address self-selection bias.The results indicate that,after accounting for self-selection,DSR adopters spend 401.72 CNY ha^(-1) more on pesticides compared to non-adopters.Although DSR adoption significantly increases the use of insecticides,fungicides and herbicides,its impact is most pronounced for insecticide expenditure and least pronounced for herbicide expenditure.The findings remain robust when altering the dependent variable,truncating the research sample,and modifying the estimation method.Heterogeneous analysis reveals that DSR adoption has a stronger positive impact on pesticide expenditure among farmers below 60 years of age,with at least 6 years of education,and managing rice sown areas less than 2 ha.Based on these findings,this study recommends enhancing complementary techniques for DSR,improving the dissemination of DSR cultivation technologies,and strengthening socialized services.This research provides a comprehensive assessment of DSR's advantages and disadvantages,particularly regarding pesticide use,offering important policy implications for pesticide reduction. 展开更多
关键词 direct-seeded rice pesticide use self-selection issue labor-saving technology China
在线阅读 下载PDF
Transforming Mesoporous Covalent Organic Polymers into Efficient 18-Electron-Redox Anodes via Redox Site Engineering for Superior Li-Ion Storage
10
作者 Fujie Liu Yaozheng Pan +5 位作者 Jicheng Cai Linfeng Zhong Yi Lin fan yang Cong Liu Dingshan Yu 《Energy & Environmental Materials》 2026年第1期46-53,共8页
Redox-active covalent organic polymers(COPs)have emerged as appealing renewable electrode materials for next-generation Li-ion batteries,but their performance is limited by insufficient redox sites and inadequate Li-i... Redox-active covalent organic polymers(COPs)have emerged as appealing renewable electrode materials for next-generation Li-ion batteries,but their performance is limited by insufficient redox sites and inadequate Li-ion diffusion.Here,we develop a novel class of mesoporous covalent organic polymer(namely TF-Azo-COP)bearing multiple redox sites and explore its first use as efficient 18-electron-redox anodes for superior Li-ion storage in both coin-type and fiber-type batteries.The newly produced TF-Azo-COP involves three types of active sites including C=N in triazines and imines,N=N in azo,and C6-ring aromatics to enable 18-Li-ion storage on one repeatable segment,while affording extendedπ-conjugation for fast electron transfer and a pore size of~2.5 nm for facilitated ion diffusion with a high coefficient up to~10^(-10)cm^(2)s^(-1)—superior to some reported organic electrodes.Meriting from the above,pairing TF-Azo-COP with metal Li endows a coin cell with good cycling stability and a large reversible capacity of 795.4 mAh g^(-1)at 0.1 A g^(-1)—representing one of the best performances among reported organic electrodes.When coupled with fiber-shaped LiFePO_(4)cathodes,the assembled fiber cell delivers an excellent combination of linear capacity(0.23 mAh cm^(-1)),energy density(0.55 mWh cm^(-1)),cycling stability(250 cycles),and good flexibility. 展开更多
关键词 covalent organic polymers fiber batteries Li-ion batteries multiple redox chemistry organic electrode materials
在线阅读 下载PDF
Advancements in synthesis strategies and environmental application of FAU-type zeolite:Bibliometric-driven review
11
作者 Lin Chen Bingqing Xu +7 位作者 Siying Wang Shan Ren fan yang Wei Zhang Yuanpei Lan Chaoyi Chen Junqi Li Yanbing Su 《Green Energy & Environment》 2026年第1期36-61,共26页
FAU zeolites have emerged as multifunctional materials with broad applications in catalysis and adsorption,owing to their hierarchical pore architectures,elevated specific surface areas,and adjustable extra-framework ... FAU zeolites have emerged as multifunctional materials with broad applications in catalysis and adsorption,owing to their hierarchical pore architectures,elevated specific surface areas,and adjustable extra-framework cationic sites.This review provides a critical overview of recent advances in FAU zeolite research with emphasis on their roles in environmental pollutant mitigation.A bibliometric analysis was performed to ascertain worldwide research trends,cooperation networks,and principal theme areas.Strategies for synthesis and functionalization,including crystallization pathways,one-pot methods,and post-synthetic modifications,were systematically evaluated for their capacity to tailor structural and physicochemical properties.Environmental applications were discussed in detail,particularly in heavy metal extraction,CO_(2)capture,and catalytic NOx reduction.Despite these advances,challenges persisted,notably restricted chemical stability under extreme pH conditions,scalability obstacles from laboratory to industrial production,and the necessity for enhanced catalytic efficiency.By integrating fundamental understanding with application-oriented perspectives,this review identifies existing knowledge gaps and delineates future directions for the rational design of FAU zeolites toward sustainable environmental remediation. 展开更多
关键词 FAU zeolite Bibliometric analysis Heavy metals adsorption CO_(2)adsorption Catalytic reduction of NOx
在线阅读 下载PDF
Micropolar homogenization constitutive modeling and size effect analysis of lattice materials
12
作者 Tingrui CHEN fan yang +2 位作者 Jingchun ZHANG Dong HAN Qingcheng yang 《Applied Mathematics and Mechanics(English Edition)》 2026年第1期39-60,共22页
Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenizatio... Lattice materials have demonstrated promising potential in engineering applications owing to their exceptional lightweight,high specific strength,and tunable mechanical properties.However,the traditional homogenization methods based on the classical elasticity theory struggle to accurately describe the non-classical mechanical behaviors of lattice materials,especially when dealing with complex unit-cell geometries featured by non-symmetric configurations or non-single central node connections.In response to this limitation,this study establishes a generalized homogenization model based on the micropolar theory framework,employing Hill's boundary conditions to precisely predict the equivalent moduli of complex lattice materials.By introducing the independent rotational degree of freedom(DOF)characteristic of the micropolar theory,the proposed model successfully overcomes the limitation of conventional methods in accurately describing the asymmetric deformation and scale effects.We initially calculate the constitutive relations of two-dimensional(2D)cross-shaped multi-node chiral lattices and subsequently extend the method to three-dimensional(3D)lattices,successfully predicting the mechanical properties of both traditional and eccentric body-centered cubic(BCC)lattices.The theoretical model is validated through the finite element numerical verification which shows excellent consistency with the theoretical predictions.A further parametric study investigates the influence of geometric parameters,revealing the underlying size-effect mechanism.This paper provides a reliable theoretical tool for the design and property optimization of complex lattice materials. 展开更多
关键词 lattice material size effect micropolar theory homogenization method constitutive relationship
在线阅读 下载PDF
国有企业预算执行偏差的财务信息化管控研究——构建智能化编制调整机制与数字化监控预警体系
13
作者 范阳 《财务管理研究》 2026年第1期122-129,共8页
在预算管理实践过程中,国有企业存在预算执行偏差引发的资源配置效率低下、战略执行不力等问题,亟须寻求有效对策加以破解。构建“智能化预算编制与动态调整机制”及“数字化预算执行监控与预警系统”双轮驱动的财务信息化管理框架,通... 在预算管理实践过程中,国有企业存在预算执行偏差引发的资源配置效率低下、战略执行不力等问题,亟须寻求有效对策加以破解。构建“智能化预算编制与动态调整机制”及“数字化预算执行监控与预警系统”双轮驱动的财务信息化管理框架,通过技术手段赋能与业务流程再造,形成涵盖预算编制、调整、执行及监控等关键环节的全流程信息化管理体系,可为国有企业解决预算执行偏差问题提供系统化、可操作的解决方案,推动财务管理向信息化、精细化转型,助力国有企业高效实现战略目标。 展开更多
关键词 国有企业 预算执行偏差 财务信息化管控 智能化编制调整 数字化监控预警
在线阅读 下载PDF
基于应力集中的拉索弹性模量换算法研究
14
作者 方钊 俞静雯 +2 位作者 杨凡 曲玉伟 居诗林 《钢结构(中英文)》 2026年第3期36-43,共8页
拉索弹性模量换算法是一种通过对拉索弹性模量进行换算从而在整体斜拉桥结构分析中考虑拉索腐蚀效应的方法。然而该方法对拉索钢丝表面复杂蚀坑分布情况下的适用性存疑,且未考虑其在蚀坑附近应力集中较大时的适用性。通过对拉索钢丝表... 拉索弹性模量换算法是一种通过对拉索弹性模量进行换算从而在整体斜拉桥结构分析中考虑拉索腐蚀效应的方法。然而该方法对拉索钢丝表面复杂蚀坑分布情况下的适用性存疑,且未考虑其在蚀坑附近应力集中较大时的适用性。通过对拉索钢丝表面蚀坑的有限元模拟,考虑两参量耦合关系,采用二元拟合方法联合拟合了蚀坑长短轴比、深度、数量、间距等参数与钢丝应力集中系数的关系,并验证了上述参数组合下弹性模量换算法的适用性,通过某斜拉桥成桥状态下拉索应力的对比,定义了该换算法的基本适用条件。结果表明:应力集中系数总体随着蚀坑长短轴比、蚀坑深度和蚀坑数量的增大而增大,随着蚀坑间距的增大而减小;弹性模量换算法可较好地适用于各蚀坑参数的组合工况并满足工程计算的精度要求,但不能直接适用于拉索局部应力值超出钢丝极限强度的情况。 展开更多
关键词 拉索弹性模量换算法 应力集中系数 腐蚀蚀坑 二元拟合
原文传递
Oxygenation-driven multimodal photoacoustic/ultrasonic imaging enhances evaluation of enthesitis disease activity in psoriatic arthritis
15
作者 Rui Zhang fan yang +8 位作者 Chenyang Zhao Ming Wang Yan Zhang fang yang Lei Zhu Jianchu Li Yuxin Jiang Xiaomei Leng Meng yang 《Journal of Innovative Optical Health Sciences》 2026年第1期126-138,共13页
Conventional ultrasound(US)evaluation of enthesitis in psoriatic arthritis(PsA)is limited by its inability to quantify metabolic alterations such as hypoxia,a key driver of disease activity.We introduce an oxygenation... Conventional ultrasound(US)evaluation of enthesitis in psoriatic arthritis(PsA)is limited by its inability to quantify metabolic alterations such as hypoxia,a key driver of disease activity.We introduce an oxygenation-integrated multimodal photoacoustic/ultrasound(PA/US)imaging framework designed to quantify entheseal oxygen saturation(SO_(2))for assessing entheseal disease activity in PsA.In this cross-sectional study,25 PsA patients underwent bilateral PA/US imaging of 12 entheses,where ultrasound lesions were scored using the Outcome Measures in Rheumatology scoring system,and PA-derived SO_(2) levels,quantified via dual-wavelength PA imaging,were classified into hyperoxia or hypoxia groups using k-means clustering.This approach provides metabolic insights complementary to conventional ultrasonic assessment.A composite score integrating hypoxia with US parameters was validated against clinical disease activity indices(Disease Activity Score 28-C-reactive protein,DAS28-CRP;Disease Activity Index for Psoriatic Arthritis,DAPSA).Among 300 entheses,103(34.3%)exhibited PA positivity,with 40(38.8%)classified as hypoxia.Hypoxia scores independently predicted DAS28-CRP(β=0.618,p=0.001)and DAPSA(β=0.612,p<0:001).The hypoxia-optimized PAUS score demonstrated superior correlation with disease activity indices compared to conventional US(DAS28-CRP:r=0.615,p=0.001 versus r=0.474,p=0.017;DAPSA:r=0.743,p<0:001 versus r=0.567,p=0.003),alongside superior diagnostic accuracy for minimal disease activity(area under the curve,AUC 0.776 versus 0.614,p=0.008)and low disease activity(AUC 0.853 versus 0.772,p=0.009).This multimodal scoring system enhances the stratification of PsA disease activity by providing unique metabolic insights,offering a potential tool for therapeutic monitoring and guiding treat-to-target strategies. 展开更多
关键词 Photoacoustic imaging oxygen saturation ENTHESIS disease activity evaluation
原文传递
时间触发以太网流量调度研究进展 被引量:2
16
作者 张秀再 范阳 周硕 《电讯技术》 北大核心 2025年第1期152-162,共11页
时间触发以太网(Time-triggered Ethernet,TTE)将时间触发技术与传统以太网的灵活性、高带宽等特性相结合,解决了传统以太网无法满足的高实时性、高可靠性问题。流量调度是TTE标准中关键技术之一,可以有效保证TTE网络可靠地实时通信。... 时间触发以太网(Time-triggered Ethernet,TTE)将时间触发技术与传统以太网的灵活性、高带宽等特性相结合,解决了传统以太网无法满足的高实时性、高可靠性问题。流量调度是TTE标准中关键技术之一,可以有效保证TTE网络可靠地实时通信。首先介绍了流量调度的基础时间同步机制,并对TTE流量调度问题进行数学描述,包括TTE网络拓扑结构、流量模型和约束条件;然后着重阐述了TTE流量调度的研究现状,分析比较不同调度算法的优缺点与不同的应用场景,归纳和总结了各种调度方案的调度流量类型、调度目标和调度性质;最后讨论了TTE流量调度的发展方向和趋势。 展开更多
关键词 时间触发以太网 时间同步机制 流量调度
在线阅读 下载PDF
对辊式叶林杜仲脱叶剥皮机设计与试验
17
作者 谷芳 宋明洋 +3 位作者 樊扬 冯腾辉 朱琳 朱铭强 《林业科学》 北大核心 2025年第10期201-210,共10页
【目的】设计开发一款对辊式叶林杜仲脱叶剥皮机,以实现连续化叶林杜仲细枝木脱叶剥皮作业,解决叶林杜仲规模化采收过程中机械化水平低的难题。【方法】在测定目标物料基本特性参数的基础上,以整机工作性能要求为主要准则,利用EDEM软件... 【目的】设计开发一款对辊式叶林杜仲脱叶剥皮机,以实现连续化叶林杜仲细枝木脱叶剥皮作业,解决叶林杜仲规模化采收过程中机械化水平低的难题。【方法】在测定目标物料基本特性参数的基础上,以整机工作性能要求为主要准则,利用EDEM软件进行仿真模拟和台架试验,得出拉削对辊的螺距、间距和转速比的最佳切割效果组合参数,确定对辊的数量与合理的传动方式;分析脱叶锤片受力情况,确定锤片机构结构尺寸与排列方式,完成装备关键零部件的设计;选择脱叶和剥皮进料辊转速、锤片辊转速等作为试验因素,以脱叶率、剥皮率和生产效率为试验指标,通过田间试验对整机工作性能进行评价。【结果】1)拉削对辊机构对杜仲树皮的切割效果随着对辊间距增大而降低,但与螺距和转速比无相关性;最佳切割效果组合参数为:拉削辊直径150 mm、长度1250 mm、螺距2.5 mm、间距10 mm、转速比1、对辊数量2组、转速400 r·min^(-1)。2)锤片机构采用定距、偶数、均布的方式排列;锤片长130 mm、宽50 mm、厚4 mm、锤片间距15 mm、数量40,对辊数量2组、转速1200 r·min^(-1)时,效果最佳。3)田间试验结果显示,基于设计参数研制的杜仲脱叶剥皮机对当年生采收1天内、含水率58%~70%的杜仲细枝木剥净率最高,脱叶率达100%,剥皮率为78%,生产效率为64%。【结论】对辊式叶林杜仲脱叶剥皮机试验的各项指标均达到设计目标,为叶林杜仲机械化采收装备的研发提供了一种参考方案。 展开更多
关键词 叶林杜仲 对辊式 锤片 脱叶机构 剥皮机构
在线阅读 下载PDF
四环高原阿朴啡碱(+)-Crociflorinone及(+)-6a-epi-Crociflorinone的不对称全合成
18
作者 杨帆 濮留洋 +1 位作者 谢建华 周其林 《有机化学》 北大核心 2025年第3期969-976,共8页
四环高原阿朴啡碱是一类具有四氢异喹啉稠合螺环骨架结构的异喹啉生物碱. 在前期完成五环高原阿朴啡碱不对称全合成的基础上, 本研究以含有季碳中心的三环手性环己酮(–)-5为起始原料, 发展了Wittig反应和Pictet-Spengler环化为关键步... 四环高原阿朴啡碱是一类具有四氢异喹啉稠合螺环骨架结构的异喹啉生物碱. 在前期完成五环高原阿朴啡碱不对称全合成的基础上, 本研究以含有季碳中心的三环手性环己酮(–)-5为起始原料, 发展了Wittig反应和Pictet-Spengler环化为关键步骤的构筑含有螺环和季碳手性中心的五环手性骨架结构的策略, 并经逆oxa-Michael开环/甲基化串联等后期官能化修饰步骤, 实现了四环高原阿朴啡碱(+)-crociflorinone及其C6a位差向异构体(+)-6a-epi-crociflorinone的首次不对称全合成, 并确定其绝对构型. 展开更多
关键词 四环高原阿朴啡碱 不对称全合成 crociflorinone Pictet-Spengler环化 异喹啉生物碱
原文传递
六妹羊肚菌几个发育阶段细胞核变化
19
作者 王晓敏 张钦语 +1 位作者 樊扬 张邦喜 《食用菌学报》 北大核心 2025年第3期51-58,共8页
采用荧光显微镜观察六妹羊肚菌(Morchella sextelata)的子囊、子囊孢子、初生菌丝和次生菌丝的细胞核结构。研究结果表明:子囊母细胞初期细胞核数量为10~24,细胞核向子囊尖端移动聚集,细胞分裂后形成8个椭圆状的子囊孢子依次竖排排列;... 采用荧光显微镜观察六妹羊肚菌(Morchella sextelata)的子囊、子囊孢子、初生菌丝和次生菌丝的细胞核结构。研究结果表明:子囊母细胞初期细胞核数量为10~24,细胞核向子囊尖端移动聚集,细胞分裂后形成8个椭圆状的子囊孢子依次竖排排列;子囊孢子从子囊中弹出后,培养6 h的子囊孢膨大到约为原来的2倍,细胞核数量由9~15增加到21~27;孢子尖端凸起长出1~2个芽管,芽管不断伸长生长并形成隔膜。初生菌丝既有单交配型也有双交配型,次生菌丝均为双交配型。初生菌丝和次生菌丝细胞核形态存在差异,大部分初生菌丝的细胞核是颗粒状,体积较小,每个细胞的细胞核数量为25~52,大部分次生菌丝从细胞核是团状,体积较大,每个细胞的细胞核数量为3~10;细胞核呈团状或粒状均可通过隔膜在细胞之间运输遗传物质。 展开更多
关键词 羊肚菌 子囊孢子 菌丝 细胞核
在线阅读 下载PDF
流体辅助注射成型及其衍生工艺
20
作者 杨帆 匡唐清 +3 位作者 柳和生 梁健康 金廷翁 彭杰 《高分子材料科学与工程》 北大核心 2025年第5期159-168,共10页
流体辅助注射成型工艺(FAIM)是一项利用压力流体完成熔体充填、保压来获得复杂中空制件的聚合物一次成型工艺。文中简要概述了近年来FAIM工艺的国内外研究进展,涵盖了气体辅助注射成型、水辅助注射成型等常规工艺,以及硅油辅助注射成型... 流体辅助注射成型工艺(FAIM)是一项利用压力流体完成熔体充填、保压来获得复杂中空制件的聚合物一次成型工艺。文中简要概述了近年来FAIM工艺的国内外研究进展,涵盖了气体辅助注射成型、水辅助注射成型等常规工艺,以及硅油辅助注射成型、液气辅助注射成型、液态二氧化碳辅助注射成型、流体驱动弹头辅助注射成型、流体辅助共注射成型、流体驱动弹头辅助共注射成型等衍生工艺。首先介绍了不同流体的穿透过程并进行了对比,进而阐述了不同工艺成型制件结晶形态及纤维取向的影响机制及差别,最后通过数值模拟进一步分析了不同工艺的成型机理差异。另外,在此基础上展望了FAIM工艺的未来研究方向。 展开更多
关键词 流体辅助注射成型 弹头注射 超临界二氧化碳 数值模拟
在线阅读 下载PDF
上一页 1 2 51 下一页 到第
使用帮助 返回顶部