期刊文献+
共找到158,515篇文章
< 1 2 250 >
每页显示 20 50 100
Fracturing mechanism of pre-damaged granite induced by multi-source dynamic disturbances in tunnels
1
作者 Biao Wang Benguo He +1 位作者 Xiating Feng Hongpu Li 《International Journal of Mining Science and Technology》 2025年第9期1439-1459,共21页
To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments,this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances... To elucidate the fracturing mechanism of deep hard rock under complex disturbance environments,this study investigates the dynamic failure behavior of pre-damaged granite subjected to multi-source dynamic disturbances.Blasting vibration monitoring was conducted in a deep-buried drill-and-blast tunnel to characterize in-situ dynamic loading conditions.Subsequently,true triaxial compression tests incorporating multi-source disturbances were performed using a self-developed wide-low-frequency true triaxial system to simulate disturbance accumulation and damage evolution in granite.The results demonstrate that combined dynamic disturbances and unloading damage significantly accelerate strength degradation and trigger shear-slip failure along preferentially oriented blast-induced fractures,with strength reductions up to 16.7%.Layered failure was observed on the free surface of pre-damaged granite under biaxial loading,indicating a disturbance-induced fracture localization mechanism.Time-stress-fracture-energy coupling fields were constructed to reveal the spatiotemporal characteristics of fracture evolution.Critical precursor frequency bands(105-150,185-225,and 300-325 kHz)were identified,which serve as diagnostic signatures of impending failure.A dynamic instability mechanism driven by multi-source disturbance superposition and pre-damage evolution was established.Furthermore,a grouting-based wave-absorption control strategy was proposed to mitigate deep dynamic disasters by attenuating disturbance amplitude and reducing excitation frequency. 展开更多
关键词 multi-source dynamic disturbances Blasting vibration Deep-buried tunnel Acoustic emission Time-delayed rockburst
在线阅读 下载PDF
A fluorescence-enhanced inverse opal sensing film for multi-sources detection of formaldehyde
2
作者 Xiaokang Lu Bo Han +6 位作者 Deyilei Wei Mingzhu Chu Haojie Ma Ran Li Xueyan Hou Yuqi Zhang Jijiang Wang 《Food Science and Human Wellness》 2025年第5期1818-1826,共9页
The SiO_(2) inverse opal photonic crystals(PC)with a three-dimensional macroporous structure were fabricated by the sacrificial template method,followed by infiltration of a pyrene derivative,1-(pyren-8-yl)but-3-en-1-... The SiO_(2) inverse opal photonic crystals(PC)with a three-dimensional macroporous structure were fabricated by the sacrificial template method,followed by infiltration of a pyrene derivative,1-(pyren-8-yl)but-3-en-1-amine(PEA),to achieve a formaldehyde(FA)-sensitive and fluorescence-enhanced sensing film.Utilizing the specific Aza-Cope rearrangement reaction of allylamine of PEA and FA to generate a strong fluorescent product emitted at approximately 480 nm,we chose a PC whose blue band edge of stopband overlapped with the fluorescence emission wavelength.In virtue of the fluorescence enhancement property derived from slow photon effect of PC,FA was detected highly selectively and sensitively.The limit of detection(LoD)was calculated to be 1.38 nmol/L.Furthermore,the fast detection of FA(within 1 min)is realized due to the interconnected three-dimensional macroporous structure of the inverse opal PC and its high specific surface area.The prepared sensing film can be used for the detection of FA in air,aquatic products and living cells.The very close FA content in indoor air to the result from FA detector,the recovery rate of 101.5%for detecting FA in aquatic products and fast fluorescence imaging in 2 min for living cells demonstrate the reliability and accuracy of our method in practical applications. 展开更多
关键词 Inverse opal photonic crystals Slow photon effect Fluorescence enhancement multi-sources detection FORMALDEHYDE
在线阅读 下载PDF
MMH-FE:AMulti-Precision and Multi-Sourced Heterogeneous Privacy-Preserving Neural Network Training Based on Functional Encryption
3
作者 Hao Li Kuan Shao +2 位作者 Xin Wang Mufeng Wang Zhenyong Zhang 《Computers, Materials & Continua》 2025年第3期5387-5405,共19页
Due to the development of cloud computing and machine learning,users can upload their data to the cloud for machine learning model training.However,dishonest clouds may infer user data,resulting in user data leakage.P... Due to the development of cloud computing and machine learning,users can upload their data to the cloud for machine learning model training.However,dishonest clouds may infer user data,resulting in user data leakage.Previous schemes have achieved secure outsourced computing,but they suffer from low computational accuracy,difficult-to-handle heterogeneous distribution of data from multiple sources,and high computational cost,which result in extremely poor user experience and expensive cloud computing costs.To address the above problems,we propose amulti-precision,multi-sourced,andmulti-key outsourcing neural network training scheme.Firstly,we design a multi-precision functional encryption computation based on Euclidean division.Second,we design the outsourcing model training algorithm based on a multi-precision functional encryption with multi-sourced heterogeneity.Finally,we conduct experiments on three datasets.The results indicate that our framework achieves an accuracy improvement of 6%to 30%.Additionally,it offers a memory space optimization of 1.0×2^(24) times compared to the previous best approach. 展开更多
关键词 Functional encryption multi-sourced heterogeneous data privacy preservation neural networks
在线阅读 下载PDF
Mechanism of Multi-Source Excitation for Whistling Sound of Gear Teeth in Automotive Electric Drive System
4
作者 Shuai Yuan Zhen Lin Wenfu Sun 《Journal of Electronic Research and Application》 2025年第4期65-70,共6页
This paper deeply discusses the causes of gear howling noise,the identification and analysis of multi-source excitation,the transmission path of dynamic noise,simulation and experimental research,case analysis,optimiz... This paper deeply discusses the causes of gear howling noise,the identification and analysis of multi-source excitation,the transmission path of dynamic noise,simulation and experimental research,case analysis,optimization effect,etc.,aiming to better provide a certain guideline and reference for relevant researchers. 展开更多
关键词 Automotive electric drive system Whistle of gear teeth multi-source excitation mechanism
在线阅读 下载PDF
Rock mass quality prediction on tunnel faces with incomplete multi-source dataset via tree-augmented naive Bayesian network 被引量:1
5
作者 Hongwei Huang Chen Wu +3 位作者 Mingliang Zhou Jiayao Chen Tianze Han Le Zhang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第3期323-337,共15页
Rock mass quality serves as a vital index for predicting the stability and safety status of rock tunnel faces.In tunneling practice,the rock mass quality is often assessed via a combination of qualitative and quantita... Rock mass quality serves as a vital index for predicting the stability and safety status of rock tunnel faces.In tunneling practice,the rock mass quality is often assessed via a combination of qualitative and quantitative parameters.However,due to the harsh on-site construction conditions,it is rather difficult to obtain some of the evaluation parameters which are essential for the rock mass quality prediction.In this study,a novel improved Swin Transformer is proposed to detect,segment,and quantify rock mass characteristic parameters such as water leakage,fractures,weak interlayers.The site experiment results demonstrate that the improved Swin Transformer achieves optimal segmentation results and achieving accuracies of 92%,81%,and 86%for water leakage,fractures,and weak interlayers,respectively.A multisource rock tunnel face characteristic(RTFC)dataset includes 11 parameters for predicting rock mass quality is established.Considering the limitations in predictive performance of incomplete evaluation parameters exist in this dataset,a novel tree-augmented naive Bayesian network(BN)is proposed to address the challenge of the incomplete dataset and achieved a prediction accuracy of 88%.In comparison with other commonly used Machine Learning models the proposed BN-based approach proved an improved performance on predicting the rock mass quality with the incomplete dataset.By utilizing the established BN,a further sensitivity analysis is conducted to quantitatively evaluate the importance of the various parameters,results indicate that the rock strength and fractures parameter exert the most significant influence on rock mass quality. 展开更多
关键词 Rock mass quality Tunnel faces Incomplete multi-source dataset Improved Swin Transformer Bayesian networks
在线阅读 下载PDF
Multi-source heterogeneous data access management framework and key technologies for electric power Internet of Things 被引量:1
6
作者 Pengtian Guo Kai Xiao +1 位作者 Xiaohui Wang Daoxing Li 《Global Energy Interconnection》 EI CSCD 2024年第1期94-105,共12页
The power Internet of Things(IoT)is a significant trend in technology and a requirement for national strategic development.With the deepening digital transformation of the power grid,China’s power system has initiall... The power Internet of Things(IoT)is a significant trend in technology and a requirement for national strategic development.With the deepening digital transformation of the power grid,China’s power system has initially built a power IoT architecture comprising a perception,network,and platform application layer.However,owing to the structural complexity of the power system,the construction of the power IoT continues to face problems such as complex access management of massive heterogeneous equipment,diverse IoT protocol access methods,high concurrency of network communications,and weak data security protection.To address these issues,this study optimizes the existing architecture of the power IoT and designs an integrated management framework for the access of multi-source heterogeneous data in the power IoT,comprising cloud,pipe,edge,and terminal parts.It further reviews and analyzes the key technologies involved in the power IoT,such as the unified management of the physical model,high concurrent access,multi-protocol access,multi-source heterogeneous data storage management,and data security control,to provide a more flexible,efficient,secure,and easy-to-use solution for multi-source heterogeneous data access in the power IoT. 展开更多
关键词 Power Internet of Things Object model High concurrency access Zero trust mechanism multi-source heterogeneous data
在线阅读 下载PDF
Evaluation of Bird-watching Spatial Suitability Under Multi-source Data Fusion: A Case Study of Beijing Ming Tombs Forest Farm
7
作者 YANG Xin YUE Wenyu +1 位作者 HE Yuhao MA Xin 《Journal of Landscape Research》 2025年第3期59-64,共6页
Taking the Ming Tombs Forest Farm in Beijing as the research object,this research applied multi-source data fusion and GIS heat-map overlay analysis techniques,systematically collected bird observation point data from... Taking the Ming Tombs Forest Farm in Beijing as the research object,this research applied multi-source data fusion and GIS heat-map overlay analysis techniques,systematically collected bird observation point data from the Global Biodiversity Information Facility(GBIF),population distribution data from the Oak Ridge National Laboratory(ORNL)in the United States,as well as information on the composition of tree species in suitable forest areas for birds and the forest geographical information of the Ming Tombs Forest Farm,which is based on literature research and field investigations.By using GIS technology,spatial processing was carried out on bird observation points and population distribution data to identify suitable bird-watching areas in different seasons.Then,according to the suitability value range,these areas were classified into different grades(from unsuitable to highly suitable).The research findings indicated that there was significant spatial heterogeneity in the bird-watching suitability of the Ming Tombs Forest Farm.The north side of the reservoir was generally a core area with high suitability in all seasons.The deep-aged broad-leaved mixed forests supported the overlapping co-existence of the ecological niches of various bird species,such as the Zosterops simplex and Urocissa erythrorhyncha.In contrast,the shallow forest-edge coniferous pure forests and mixed forests were more suitable for specialized species like Carduelis sinica.The southern urban area and the core area of the mausoleums had relatively low suitability due to ecological fragmentation or human interference.Based on these results,this paper proposed a three-level protection framework of“core area conservation—buffer zone management—isolation zone construction”and a spatio-temporal coordinated human-bird co-existence strategy.It was also suggested that the human-bird co-existence space could be optimized through measures such as constructing sound and light buffer interfaces,restoring ecological corridors,and integrating cultural heritage elements.This research provided an operational technical approach and decision-making support for the scientific planning of bird-watching sites and the coordination of ecological protection and tourism development. 展开更多
关键词 multi-source data fusion GIS heat map Kernel density analysis bird-watching spot planning Habitat suitability
在线阅读 下载PDF
Runout prediction of potential landslides based on the multi-source data collaboration analysis on historical cases
8
作者 Jun Sun Yu Zhuang Ai-guo Xing 《China Geology》 CAS CSCD 2024年第2期264-276,共13页
Long runout landslides involve a massive amount of energy and can be extremely hazardous owing to their long movement distance,high mobility and strong destructive power.Numerical methods have been widely used to pred... Long runout landslides involve a massive amount of energy and can be extremely hazardous owing to their long movement distance,high mobility and strong destructive power.Numerical methods have been widely used to predict the landslide runout but a fundamental problem remained is how to determine the reliable numerical parameters.This study proposes a framework to predict the runout of potential landslides through multi-source data collaboration and numerical analysis of historical landslide events.Specifically,for the historical landslide cases,the landslide-induced seismic signal,geophysical surveys,and possible in-situ drone/phone videos(multi-source data collaboration)can validate the numerical results in terms of landslide dynamics and deposit features and help calibrate the numerical(rheological)parameters.Subsequently,the calibrated numerical parameters can be used to numerically predict the runout of potential landslides in the region with a similar geological setting to the recorded events.Application of the runout prediction approach to the 2020 Jiashanying landslide in Guizhou,China gives reasonable results in comparison to the field observations.The numerical parameters are determined from the multi-source data collaboration analysis of a historical case in the region(2019 Shuicheng landslide).The proposed framework for landslide runout prediction can be of great utility for landslide risk assessment and disaster reduction in mountainous regions worldwide. 展开更多
关键词 Landslide runout prediction Drone survey multi-source data collaboration DAN3D numerical modeling Jianshanying landslide Guizhou Province Geological hazards survey engineering
在线阅读 下载PDF
Enhanced permeability prediction in porous media using particle swarm optimization with multi-source integration
9
作者 Zhiping Chen Jia Zhang +2 位作者 Daren Zhang Xiaolin Chang Wei Zhou 《Artificial Intelligence in Geosciences》 2024年第1期282-293,共12页
Accurately and efficiently predicting the permeability of porous media is essential for addressing a wide range of hydrogeological issues.However,the complexity of porous media often limits the effectiveness of indivi... Accurately and efficiently predicting the permeability of porous media is essential for addressing a wide range of hydrogeological issues.However,the complexity of porous media often limits the effectiveness of individual prediction methods.This study introduces a novel Particle Swarm Optimization-based Permeability Integrated Prediction model(PSO-PIP),which incorporates a particle swarm optimization algorithm enhanced with dy-namic clustering and adaptive parameter tuning(KGPSO).The model integrates multi-source data from the Lattice Boltzmann Method(LBM),Pore Network Modeling(PNM),and Finite Difference Method(FDM).By assigning optimal weight coefficients to the outputs of these methods,the model minimizes deviations from actual values and enhances permeability prediction performance.Initially,the computational performances of the LBM,PNM,and FDM are comparatively analyzed on datasets consisting of sphere packings and real rock samples.It is observed that these methods exhibit computational biases in certain permeability ranges.The PSOPIP model is proposed to combine the strengths of each computational approach and mitigate their limitations.The PSO-PIP model consistently produces predictions that are highly congruent with actual permeability values across all prediction intervals,significantly enhancing prediction accuracy.The outcomes of this study provide a new tool and perspective for the comprehensive,rapid,and accurate prediction of permeability in porous media. 展开更多
关键词 Porous media Particle swarm optimization algorithm multi-source data integration Permeability prediction
在线阅读 下载PDF
能谱CT单能量成像对结直肠癌供血动脉图像质量及辐射剂量的影响 被引量:2
10
作者 刘海燕 邱晓晖 +3 位作者 章辉庆 锁咏梅 王超 王亚丽 《中国CT和MRI杂志》 2025年第1期159-161,共3页
目的 探讨能谱CT单能量成像对结直肠癌供血动脉图像质量及辐射剂量的影响。方法 选取医院2021年1月至2022年10月收治的92例结直肠癌患者,依据是否接受能谱CT单能量扫描分为常规CT组(n=33)与能谱CT组(n=59),将能谱组CT依据扫描能量分为50... 目的 探讨能谱CT单能量成像对结直肠癌供血动脉图像质量及辐射剂量的影响。方法 选取医院2021年1月至2022年10月收治的92例结直肠癌患者,依据是否接受能谱CT单能量扫描分为常规CT组(n=33)与能谱CT组(n=59),将能谱组CT依据扫描能量分为50keV组、70keV组、90keV组、110keV组,对比不同组别患者动脉期、静脉期肿瘤病灶的对比噪声比(CNR)、信噪比(SNR)及图像质量主观评分,同时比较不同组别扫描辐射剂量。结果 动脉期常规CT组与能谱CT各能量组间CNR、SNR、主观评分比较,差异均有统计学意义(P<0.05);且能谱CT组中50keV组动脉期CNR大于常规组及其他keV组,差异有统计学意义(P<0.05);静脉期常规CT组与能谱CT各能量组间CNR、SNR、主观评分比较,差异均有统计学意义(P<0.05);且能谱CT组中50keV组静脉期CNR、主观评分大于常规组及其他keV组,差异有统计学意义(P<0.05);两组DLP比较,差异无统计学意义(P>0.05);能谱CT组动脉期、静脉期及延迟期扫描有效辐射剂量均低于非能谱组,差异有统计学意义(P<0.05)。结论 与常规CT扫描相比,采用能谱CT单能量成像可降低辐射剂量,且应用50keV单能量重建可得到质量优异的结直肠癌供血动脉CT图像。 展开更多
关键词 结直肠癌 能谱ct 单能量成像 信噪比 对比噪声比
暂未订购
基于双源CT的影像学模型对儿童上尿路结石的诊断价值 被引量:1
11
作者 唐琴 吴广巍 +4 位作者 孙亮 刘克明 曲源 陈杰 艾尼瓦尔·玉素甫 《中国CT和MRI杂志》 2025年第1期143-146,共4页
目的 探讨基于双源CT(dual-source CT,DSCT)的影像学模型用于儿童上尿路不同成分结石分析的诊断价值。方法 收集2021年1月至2022年12月间上尿路结石的53例患儿作为研究对象。其中体内的结石分析应用双能量方式进行扫描,而体外结石则将... 目的 探讨基于双源CT(dual-source CT,DSCT)的影像学模型用于儿童上尿路不同成分结石分析的诊断价值。方法 收集2021年1月至2022年12月间上尿路结石的53例患儿作为研究对象。其中体内的结石分析应用双能量方式进行扫描,而体外结石则将其放置于新鲜的猪肾内并全部浸于生理盐水中再扫描,体内和体外结石的扫描条件一致。在其软组织窗分别采用80kV、120kV和140kV电压下测定患儿结石的CT值,并采用双能量结石分析的相关软件对其主要成分进行判断。同时应用前期文献构建的影像组学预测模型和红外光谱分析结石样品的主要成分。结果 影像组学预测模型和采用红外光谱法分析发现29例纯结石,5例为混合结石。24例术前采用DSCT扫描发现21例纯结石, 2例混合结石。经统计分析,草酸钙结石、尿酸结石、羟基磷灰石、胱氨酸结石这四种纯结石年龄之间经统计分析,不具有显著性差异,男女患儿发病情况经统计分析,具有显著性差异。对比体内、外草酸钙结石、羟基磷灰石、尿酸结石、胱氨酸结石的扫描CT值在80kV、120kV和40kV下经统计分析,不具有显著性差异。不同的结石采用DSCT法(80kV和140kV)时CT值的差值和DEI值经统计学分析,具有显著性差异;采用常规扫描方法和DSCT法测定的ED值、CTDIvol值和DLP值经统计分析,均具有显著性差异(P<0.05),其中DSCT法均高于常规扫描法。结论 四种纯结石在不同电压下进行体内或体外扫描其CT值均无显著性差异,可见CT可作为临床上分析儿童上尿路结石成分的准确方法之一。结合CT值测量及DSCT分析软件可显著提高诊断的准确性,可在临床上推广应用。 展开更多
关键词 双源ct 双能量成像 上尿路结石 儿童 诊断价值
暂未订购
弥漫大B细胞淋巴瘤^(18)F-FDG PET/CT特点及预测骨髓浸润的价值 被引量:2
12
作者 杨满 黄琰 +4 位作者 孙凤霞 张灵秀 朱璐遥 刘宪凯 王秀峰 《中国CT和MRI杂志》 2025年第1期180-182,共3页
目的探讨弥漫大B细胞淋巴瘤(DLBCL)18氟-脱氧葡萄糖(^(18)F-FDG)正电子发射断层/计算机断层扫描(PET/CT)特点及预测骨髓浸润的价值。方法回顾性分析70例经病理确诊为DLBCL患者的^(18)F-FDG PET/CT影像资料,以PET/CT存在局灶性骨髓浸润... 目的探讨弥漫大B细胞淋巴瘤(DLBCL)18氟-脱氧葡萄糖(^(18)F-FDG)正电子发射断层/计算机断层扫描(PET/CT)特点及预测骨髓浸润的价值。方法回顾性分析70例经病理确诊为DLBCL患者的^(18)F-FDG PET/CT影像资料,以PET/CT存在局灶性骨髓浸润灶认定为骨髓浸润,根据是否发生骨髓浸润分为骨髓浸润组和骨髓正常组。其中骨髓浸润组分为局部浸润、弥漫浸润、局部伴弥漫浸润三组。观察代谢参数最大标准化摄取值(SUVmax)、肿瘤代谢体积(MTV)、病灶糖酵解总量(TLG)值,使用Spearman分析影像参数与Ann Arbor分期的相关性。绘制受试者工作特征曲线(ROC)分析PET/CT对骨髓浸润的诊断价值。结果经^(18)F-FDG PET/CT检查发现,骨髓浸润16例(22.86%),骨髓正常54例(78.14%),骨髓浸润中,局部浸润2例(12.50%)、弥漫浸润4例(25.00%)、局部伴弥漫浸润10例(62.50%);对比骨髓浸润组与骨髓正常组的^(18)F-FDGPET/CT参数发现,骨髓浸润组SUVmax、MTV和TLG值均高于骨髓正常组(P<0.05);对比不同临床分期的^(18)F-FDG PET/CT参数发现,4个临床分期的SUVmax、MTV和TLG值差异显著,均随着临床分期的进程而升高(P<0.05);Spearman分析显示,SUVmax、MTV和TLG与临床分期均成正相关(r=0.944,r=0.569,r=0.982,P均<0,001);SUVmax、MTV和TLG诊断骨髓浸润的AUC的面积分别为0.999、0.700、0.994(P均<0.05)。结论^(18)F-FDG PET/CT诊断DLBCL患者效能较高,其影像参数均呈现较高水平,与临床分期具有相关性,且其对骨髓浸润诊断价值较高。 展开更多
关键词 弥漫大B细胞淋巴瘤 ^(18)氟-脱氧葡萄糖 PET/ct 骨髓浸润
暂未订购
多模型自适应统计迭代重建算法在高原地区儿童超低剂量胸部CT检查中的应用 被引量:2
13
作者 王先涛 白瑞婷 +3 位作者 次旦旺久 索朗尼玛 尼玛卓嘎 苏佰燕 《中国医学科学院学报》 北大核心 2025年第1期29-34,共6页
目的探讨多模型自适应统计迭代重建(ASiR-Ⅴ)算法在高原地区儿童超低剂量胸部CT检查中的应用价值。方法收集西藏自治区人民医院行胸部CT检查的儿童患者,根据扫描条件分为两组:A组采用管电压100 kV,并进行ASiR-Ⅴ50%重建;B组采用管电压80... 目的探讨多模型自适应统计迭代重建(ASiR-Ⅴ)算法在高原地区儿童超低剂量胸部CT检查中的应用价值。方法收集西藏自治区人民医院行胸部CT检查的儿童患者,根据扫描条件分为两组:A组采用管电压100 kV,并进行ASiR-Ⅴ50%重建;B组采用管电压80 kV,分别进行ASiR-Ⅴ0(B1组)和ASiR-Ⅴ50%(B2组)重建,对各组图像质量进行主观及客观评分,比较各组的辐射剂量及图像质量。结果A组和B组容积CT剂量指数分别为(2.33±0.62)、(0.86±0.01)mGy,两组比较差异有统计学意义(P<0.001),剂量长度乘积分别为(65.01±25.12)、(23.55±3.38)mGy·cm,两组比较差异有统计学意义(P<0.001)。肺窗B2组双上肺、双中肺噪声值低于B1组,但均高于A组(P均<0.001);各组肺窗图像质量评分比较差异无统计学意义(P均>0.05)。纵隔窗A组、B1组和B2组升主动脉(P=0.538)和肝脏CT值(P=0.175)比较差异无统计学意义,B2组升主动脉和肝脏信噪比(P均<0.001)、对比噪声比(P均<0.001)均高于B1组,且低于A组(P均<0.05);纵隔窗图像质量评分A组高于B2组,且均高于B1组(P均<0.001)。结论ASiR-Ⅴ联合低管电压在有效降低辐射剂量的同时,能够保障高原地区儿童胸部CT的图像质量。 展开更多
关键词 自适应统计迭代重建算法 儿童 低剂量 多层螺旋ct
暂未订购
艾滋病合并肺孢子菌肺炎患者的临床与CT表现及其预后危险因素分析 被引量:1
14
作者 蒋蕾 贾西中 +2 位作者 张玉 李宏军 王伟 《中国病原生物学杂志》 北大核心 2025年第2期195-200,共6页
目的探讨艾滋病(AIDS)患者合并肺孢子菌肺炎(Pneumocystis pneumonia,PCP)的临床表现、CT影像表现及其危险因素,以期为早期诊断和干预提供依据。方法回顾性分析2015年1月至2023年12月期间在本院收治的30例确诊艾滋病合并PCP患者的临床... 目的探讨艾滋病(AIDS)患者合并肺孢子菌肺炎(Pneumocystis pneumonia,PCP)的临床表现、CT影像表现及其危险因素,以期为早期诊断和干预提供依据。方法回顾性分析2015年1月至2023年12月期间在本院收治的30例确诊艾滋病合并PCP患者的临床及影像学资料。收集患者的人口学信息、临床症状、实验室指标、治疗方案及病程结果。通过高分辨率CT(HRCT)评估肺部病变的影像学特征,包括磨玻璃影、间质性病变、肺大疱及气胸的发生率。使用单因素及多因素Logistic回归分析,评估临床预后不良的独立危险因素,并计算其相对风险(OR)。结果共纳入30例患者,平均年龄36.5±8.2岁,男性占83.33%(25例)。主要临床表现为呼吸困难(80.00%,24例)、干咳(86.66%,26例)和发热(76.66%,23例),其中66.66%(20例)患者伴有体重减轻超过10%。CD4^(+)T细胞计数均值为92±28 cells/μL,56.66%(17例)患者CD4计数低于50cells/μL。乳酸脱氢酶(LDH)水平升高的患者占70.00%(21例),LDH均值为566.3±154.8U/L。C反应蛋白(CRP)均值为52.4±18.7mg/L,57%(17例)患者存在低氧血症(PaO2<70 mmHg),PaO2均值为65.4±10.2mmHg。其他实验室指标中,43.33%(13例)患者D-二聚体升高,66.66%(20例)血清白蛋白低于正常值,血红蛋白均值为98.7±15.2g/L。影像学表现显示,93.33%(28例)患者出现双侧磨玻璃影,46.66%(14例)伴有间质性纤维化,20.00%(6例)伴发气胸。磨玻璃影面积大于50%的患者中,80.95%(17/21例)发生低氧血症,而面积小于50%的患者中无低氧血症发生(P<0.001)。多因素Logistic回归分析表明,CD4^(+)T细胞计数低于50 cells/μL(OR=4.98,95%CI:1.99-12.45,P=0.001)、乳酸脱氢酶(LDH)>500U/L(OR=3.85,95%CI:1.37-10.78,P=0.010)、PaO2<70mmHg(OR=6.14,95%CI:2.14-17.62,P=0.001)、气胸并发症(OR=4.76,95%CI:1.10-20.55,P=0.037)及磨玻璃影面积>50%(OR=5.21,95%CI:1.31-20.71,P=0.019)是PCP患者预后不良的独立危险因素。结论艾滋病患者合并肺孢子菌肺炎的临床表现以呼吸困难、干咳和发热为主,CT表现以双侧弥漫性磨玻璃影为典型,部分患者伴随间质性纤维化和气胸。CD4^(+)T细胞计数低于50cells/μL、高乳酸脱氢酶水平、气胸并发症及磨玻璃影面积大于50%均是PCP患者预后不良的独立危险因素。加强高危患者的早期识别与干预可能有助于改善临床结局。 展开更多
关键词 艾滋病 肺孢子菌肺炎 高分辨率ct 影像学 危险因素 预后
原文传递
基于能谱CTA的下肢动脉闭塞性疾病支架效果显示评价 被引量:2
15
作者 黄欣 丁宁宁 +5 位作者 周丽 赵文哲 李达亮 刘哲 杨健 金超 《西安交通大学学报(医学版)》 北大核心 2025年第1期178-183,共6页
目的 探讨能谱CT单能量成像技术在提高下肢动脉硬化闭塞性疾病支架置入CT血管成像(CTA)图像质量及支架显示中的临床价值。方法 回顾性分析我院接受下肢动脉能谱CTA检查的20例下肢动脉慢性闭塞性疾病支架植入患者的图像资料[年龄(65.61&#... 目的 探讨能谱CT单能量成像技术在提高下肢动脉硬化闭塞性疾病支架置入CT血管成像(CTA)图像质量及支架显示中的临床价值。方法 回顾性分析我院接受下肢动脉能谱CTA检查的20例下肢动脉慢性闭塞性疾病支架植入患者的图像资料[年龄(65.61±9.65)岁;男/女:16/4]。原始图像重建为7组单能量图像(40~100 keV)、120 kVp、虚拟平扫(VUE)和去金属伪影(MAR)技术图像。图像经去骨处理后,以容积重建(VR)、最大密度投影(MIP)和曲面重建(CPR)显示支架,并进行客观和主观评估,通过单因素方差分析进行比较。结果 与其他重建组图像相比,80 keV和MAR图像评分最高(P<0.01)。结论 80 keV单能量成像技术和MAR提高了下肢动脉支架内腔和结构的图像质量,为临床医师提供了更高的诊断价值。 展开更多
关键词 下肢动脉慢性闭塞性疾病 能谱ct血管成像 单能量成像 下肢动脉 动脉支架
暂未订购
基于微CT建模的小麦籽粒力学特性有限元分析 被引量:1
16
作者 任广跃 张帅 +5 位作者 李琳琳 刘文超 曹伟伟 卫新雨 吴向天 段续 《农业工程学报》 北大核心 2025年第10期80-89,共10页
为探究不同粒型小麦在挤压破碎过程中的力学行为,探索粒型对小麦力学特性、应力、应变及总变形规律的影响,该研究以含水率为16%的小麦籽粒为研究对象,采用微CT(X-ray micro-computed tomography)扫描建模与有限元分析相结合的方法,精确... 为探究不同粒型小麦在挤压破碎过程中的力学行为,探索粒型对小麦力学特性、应力、应变及总变形规律的影响,该研究以含水率为16%的小麦籽粒为研究对象,采用微CT(X-ray micro-computed tomography)扫描建模与有限元分析相结合的方法,精确构建小麦籽粒的三维模型,系统分析了不同粒型小麦在挤压破碎过程中的力学特性、应力、应变及总变形分布规律。结果表明,小麦粒型与力学响应行为密切相关,较大小麦籽粒具有更高的抗压强度和弹性模量,且应力集中主要发生在籽粒腹沟区域。整体挤压分析表明,不同粒型的小麦裂纹生成规律相似;在腹式和侧式压缩下,裂纹均沿腹沟处产生,并延腹沟向内部延伸,这一结果通过微CT扫描模型的精确建模与有限元模拟得到了验证,同时将小麦颗粒受挤压时的应力应变及总变形分布情况可视化,以表征小麦颗粒在挤压过程中的力学行为。通过微CT扫描小麦压缩后的裂纹与有限元模拟后腹沟处应力集中的现象进行对比,从试验与仿真双重角度验证了腹沟区域其特有的结构特征。本研究通过微CT扫描与有限元分析的结合,揭示了小麦腹沟作为力学薄弱区域的结构特性,构建了精准的挤压模型,为优化制粉工艺参数、实现小麦精准低损加工提供了理论模型与设计依据。 展开更多
关键词 小麦籽粒 力学特性 抗压强度 ct扫描 有限元
在线阅读 下载PDF
CT放射组学鉴别诊断周围型小细胞肺癌和非小细胞肺癌的价值研究 被引量:1
17
作者 靳强 高俊萍 +2 位作者 王欢 江涛 孙红红 《中国CT和MRI杂志》 2025年第1期47-49,共3页
目的 本研究旨在评估C T放射学方法鉴别周围型小细胞肺癌和非小细胞肺癌的研究,以期为临床诊治提供参考。方法回顾性研究原发性肺癌患者的临床资料,利用诊断后、治疗前的肺部CT图像对肺癌进行分割。从基于直方图的统计、肿瘤图像纹理分... 目的 本研究旨在评估C T放射学方法鉴别周围型小细胞肺癌和非小细胞肺癌的研究,以期为临床诊治提供参考。方法回顾性研究原发性肺癌患者的临床资料,利用诊断后、治疗前的肺部CT图像对肺癌进行分割。从基于直方图的统计、肿瘤图像纹理分析及其小波变换中提取放射学特征。特征选择采用最小冗余度和最大相关法。用多层人工神经网络建立预测模型,用受试者工作特征曲线(AUC)下面积评价SCLC/NSCLC腺癌分类器的性能。结果69例小细胞肺癌和34例非小细胞肺癌患者相比,小细胞肺癌组男性患者和吸烟者多于非小细胞肺癌组(P<0.05)。我们的SCLC/NSCLC分类器的总体性能AUC为0.93(95%可信区间=[0.85,0.97],灵敏度=0.85,特异度=0.85)。添加如吸烟史等临床数据,可略微改善性能。排名最靠前的放射学特征主要是纹理特征。结论 CT放射组学能定量反映肿瘤的异质性,可用于肺癌亚型的鉴别诊断,效果满意。用小波变换技术对CT图像进行处理,增强了小细胞肺癌/非小细胞肺癌的放射学特征。 展开更多
关键词 ct 周围型小细胞肺癌 非小细胞肺癌 放射学特征
暂未订购
CTA联合超声血流参数评估颈动脉斑块稳定性 被引量:1
18
作者 张奇 郭翀 +3 位作者 范光亮 赵斌 钟晓飞 李克 《放射学实践》 北大核心 2025年第5期567-572,共6页
目的:探讨CTA联合超声血流参数对颈动脉斑块稳定性的评估价值。方法:纳入2021年1月至2023年12月于滨州医学院附属医院就诊并接受颈内动脉剥脱术的102例颈动脉粥样硬化(CAS)斑块患者作为研究对象,根据术后病理检查结果将斑块分为稳定性... 目的:探讨CTA联合超声血流参数对颈动脉斑块稳定性的评估价值。方法:纳入2021年1月至2023年12月于滨州医学院附属医院就诊并接受颈内动脉剥脱术的102例颈动脉粥样硬化(CAS)斑块患者作为研究对象,根据术后病理检查结果将斑块分为稳定性斑块组(62例)和不稳定性斑块组(40例)。所有患者均于入院后行头颈部CTA检查,记录点状钙化、低衰减斑块、餐巾环征、正性重构、钙化斑块体积、脂质斑块体积、纤维斑块体积及最大斑块长度;并进行超声检查,对峰值收缩期流速(PSV)、舒张末期流速(EDV)、收缩期与舒张期流速比率(S/D)、阻力指数(RI)、搏动指数(PI)、管腔狭窄程度、回声强弱进行记录。结果:与不稳定斑块组相比,稳定斑块组的低衰减斑块出现比例显著降低,钙化斑块体积、PSV、EDV显著升高,脂质斑块体积、RI显著降低,管腔狭窄程度较轻、斑块回声较强,差异有统计学意义(P<0.05);而S/D和PI在两组间差异无统计学意义(P>0.05)。多因素Logistic回归分析结果显示,低衰减斑块、较大的脂质斑块体积、较低的PSV和EDV、较严重的管腔狭窄程度、较低的斑块回声,是不稳定斑块的独立影响因素(P<0.05)。ROC曲线分析结果显示,CTA联合超声血流参数评估不稳定斑块的AUC为0.910(95%CI:0.851~0.970),敏感度和特异度分别为90.0%和83.9%。结论:CTA联合超声血流参数对于不稳定CAS斑块的无创性诊断具有较高的效能,可为临床诊疗提供重要参考依据。 展开更多
关键词 ct血管成像 超声检查 体层摄影术 X线计算机 颈动脉粥样硬化斑块 稳定性
暂未订购
CT血管成像联合CT灌注成像在急性脑梗死患者取栓后出血转化中的应用价值 被引量:1
19
作者 钟伟 凌维汉 +2 位作者 石玉良 张胜 熊波 《心肺血管病杂志》 2025年第2期179-185,共7页
目的:CT血管成像(CT angiography,CTA)与CT灌注成像(CT perfusion,CTP)在急性脑梗死患者取栓后出血转化中的应用价值。方法:回顾性分析2021年1月至2024年5月在梅州市人民医院就诊的96例急性脑梗死取栓患者的临床资料进行研究。按照头颅... 目的:CT血管成像(CT angiography,CTA)与CT灌注成像(CT perfusion,CTP)在急性脑梗死患者取栓后出血转化中的应用价值。方法:回顾性分析2021年1月至2024年5月在梅州市人民医院就诊的96例急性脑梗死取栓患者的临床资料进行研究。按照头颅影像学检查结果将7d内是否发生出血转化的患者分为发生组(n=66)与未发生组(n=30)。收集两组患者的一般资料、影像学资料进行单因素分析。应用受试者工作特征曲线分析CTA与CTP参数对急性脑梗死患者取栓后出血转化的预测价值,并使用Logistic逐步回归计算方法将上述有统计学意义参数指标逐步联合后再分析其联合评估的预测价值。对单因素分析有差异变量使用Logistic回归分析探讨急性脑梗死患者取栓后发生出血转化的影响因素。结果:两组患者年龄、入院时血糖、收缩压、合并糖尿病占比,差异有统计学意义(P<0.05)。发生组患者Alberta卒中项目早期CT评分(7.3±0.9)分低于未发生组(8.5±1.6)分,差异有统计学意义(t=4.553,P<0.001)。发生组患者脑血容量、脑血流量低于未发生组,平均通过时间、达峰时间长于未发生组(P<0.05)。应用受试者工作特征曲线分析显示,Alberta卒中项目早期CT评分、脑血容量、脑血流量、平均通过时间、达峰时间以及各指标联合预测急性脑梗死患者取栓后出血转化的曲线下面积分别为0.779、0.685、0.763、0.689、0.681、0.896,具有一定预测价值(P<0.05)。Logistic回归分析显示,入院血糖≥6.9 mmol/L、有糖尿病、Alberta卒中项目早期CT评分≤7.0分、脑血容量≤2.1 mL/100 mL、脑血流量≤17.1 mL/(100 mL·min)、平均通过时间>10.5 s、达峰时间>20.8 s是急性脑梗死患者取栓后发生出血转化的影响因素。结论:CTA+CTP联合检测对急性脑梗死患者取栓后出血转化有重要意义,值得临床推广。 展开更多
关键词 ct血管成像 ct灌注成像 急性脑梗死患者 出血转化
暂未订购
CT影像特征联合C-TIRADS分类、超微细血流显像鉴别甲状腺结节良恶性的价值分析 被引量:1
20
作者 马炎 许文哲 +1 位作者 赵玮 霍晓光 《临床放射学杂志》 北大核心 2025年第3期423-428,共6页
目的探讨CT影像特征联合中国超声甲状腺影像报告和数据系统(C-TIRADS)分类、超微细血流显像(SMI)鉴别甲状腺结节良恶性的应用价值。方法回顾性搜集2023年1月至2024年1月于淄博市中心医院检查发现甲状腺结节的178例患者。所有患者均行颈... 目的探讨CT影像特征联合中国超声甲状腺影像报告和数据系统(C-TIRADS)分类、超微细血流显像(SMI)鉴别甲状腺结节良恶性的应用价值。方法回顾性搜集2023年1月至2024年1月于淄博市中心医院检查发现甲状腺结节的178例患者。所有患者均行颈部CT、常规超声、SMI检查。比较良恶性甲状腺结节的CT影像特征、超声C-TIRADS分类结果、超声影像特征、SMI的Adler血流信号分级分布和血流形态分级分布;Logistic回归分析CT影像特征、超声影像特征与甲状腺结节良恶性鉴别的关系;计算并比较CT影像特征、超声C-TIRADS分类和SMI分级对甲状腺结节良恶性的诊断效能。结果良性组的形态规则、边界清晰、粗颗粒钙化、包膜完整、结节位于腺体内、均匀强化、囊实性检出率高于恶性组,纵横比≥1、钙化、低回声检出率低于恶性组;良性组4B以上分类的甲状腺结节少于恶性组;良性组的2~3级血流信号比例和Ⅲ~Ⅳ级血流形态比例低于恶性组;Logistic回归分析显示形态、边界、钙化程度、包膜完整度、结节位置是CT鉴别甲状腺结节良恶性的独立影响因素,边界、纵横比、钙化程度、回声、囊性变是超声鉴别甲状腺结节良恶性的独立影响因素;CT单独检查敏感度较低,特异度较高,其准确率、阳性预测值与C-TIRADS、SMI相当,C-TIRADS和SMI单独检查均具有较高的敏感度,但特异度、准确率、阳性预测值均低于三者联合检测(均P<0.05)。结论相较于CT、C-TIRADS分类和SMI单独应用,三者联合可提高对甲状腺良恶性结节诊断的敏感度、特异度和准确率,其诊断效能最佳。 展开更多
关键词 甲状腺结节 ct影像 C-TIRADS指南 超微细血流显像 预测价值
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部