期刊文献+
共找到56,956篇文章
< 1 2 250 >
每页显示 20 50 100
The remarkable effect of amino hydrogen on membrane permeability and organelle staining of 1,8-naphthalimide dyes
1
作者 Zhifeng Li Qinglong Qiao +6 位作者 Ning Xu Kai An Wenchao Jiang Yi Tao Pengjun Bao Yinchan Zhang Zhaochao Xu 《Chinese Chemical Letters》 SCIE CAS CSCD 2024年第2期347-351,共5页
Membrane permeability and intracellular diffusion of fluorescent probes determine staining selectivity of intracellular substructures.However,the relationship between the molecular structure of fluorescent probes and ... Membrane permeability and intracellular diffusion of fluorescent probes determine staining selectivity of intracellular substructures.However,the relationship between the molecular structure of fluorescent probes and their membrane permeability and intracellular distribution is poorly understood.In this paper,we reported a series of 1,8-naphthalimide dyes and carried out cell imaging experiments,and found that the presence of amino hydrogen in these dyes played a crucial role in their cell membrane permeability and intracellular distribution.The secondary amino group containing compounds 1-4 show excellent membrane permeability and strong fluorescence in living cells.While the tertiary amine containing dyes 5 and 6 can hardly permeate the cell membrane though they show extremely similar structure with compounds 2-4.Compound 1 can selectively image lipid droplets by selecting the wavelength of excitation light.With the specificity for lysosomes,2 and 4 have been used in long-term time-lapses imaging of lysosomal dynamics and tracking the process of lysosome-lysosome interaction,fusion and movement.The effect of hydrogen-containing amino substituent on the cell membrane permeability of fluorescent molecules is promising for the development of better biocompatible probes. 展开更多
关键词 Amino hydrogen 1 8-naphthalimide Cell permeability Lipid droplet LYSOSOME
原文传递
Fluorescence Enhancement of Polyamine Derivatives of 1,8-Naphthalimide with Transition Metal Ions
2
作者 文国涛 朱满洲 +3 位作者 王卓 孟祥明 胡惠媛 郭庆祥 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 北大核心 2006年第6期506-510,共5页
A series of fluorescent chemosensors 1-3 were synthesized to detect transition metal ions. At the room temperature, fluorescence intensities of these chemosensors in acetonitrile without transition metal ions were fou... A series of fluorescent chemosensors 1-3 were synthesized to detect transition metal ions. At the room temperature, fluorescence intensities of these chemosensors in acetonitrile without transition metal ions were found to be very weak, due to the process of the efficient intramolecular photoinduced electron transfer (PET). However, after addition of the transition metal ions, the chemoscnsor 1-3 exhibits obvious fluorescence enhancement. Moreover, the intensity of the fluorescence emission of chemosensors increases significantly in the presence of Zn^2+ and Cd^2+. The fluorescent chemosensors with different polyamine as receptors show diverse affinity abilities to the transition metal ions and signal the receptor-metal ion interaction by the intensity change of fluorescence emission. 展开更多
关键词 Transition metal ion 1 8-naphthalimide Photoinduced electron transfer Fluorescence enhancement Fluorescent chemosensor
在线阅读 下载PDF
Fluorescent and thermal properties of siloxane-polyurethanes based on 1,8-naphthalimide 被引量:9
3
作者 Yan Ma Qian-Yun Tang +2 位作者 Ji Zhu Li-Hong Wang Cheng Yao 《Chinese Chemical Letters》 SCIE CAS CSCD 2014年第5期680-686,共7页
A series of fluorescent siloxane-polyurethanes(HPMS-PUs) containing an amino-functionalized,1 8-naphthalimide,fluorescent monomer(AABD) as a chain extender were synthesized.The properties of the HPMS-PUs were inve... A series of fluorescent siloxane-polyurethanes(HPMS-PUs) containing an amino-functionalized,1 8-naphthalimide,fluorescent monomer(AABD) as a chain extender were synthesized.The properties of the HPMS-PUs were investigated by UV–vis and fluorescence spectroscopies,thermogravimetric analysis and thermal migration behavior.The maximum absorption and emission wavelengths of HPMS-PUs showed a red shift of about 4 nm and a blue shift of about 9 nm,respectively,compared to those of AABD.The Stokes shifts of AABD and HPMS-PU2 were 3514 and 2931 cm 1,respectively.The quantum yield of HPMS-PU2 was 0.79,which was six times higher than that of AABD.Concentration self-quenching was observed in both AABD and HPMS-PUs.The fluorescence of HPMS-PUs was quite stable with respect to both temperature and fluorescence quencher effects.The thermal stability of HPMS-PUs increased with AABD content.The fluorophore units in the HPMS-PUs did not readily migrate. 展开更多
关键词 Polysiloxane Polyurethane 1 8-naphthalimide Fluorescence Thermal properties
原文传递
New trends of molecular probes based on the fluorophore4-amino-1,8-naphthalimide 被引量:1
4
作者 Lin Zhou Lijuan Xie +1 位作者 Chuanhao Liu Yi Xiao 《Chinese Chemical Letters》 SCIE CAS CSCD 2019年第10期1799-1808,共10页
4-Amino-1,8-naphthalimide(ANI) represents a valuable fluorophore from which a large number of probes have been derived in order to meet the requirements from the fields of biological sensing and imaging. In this revie... 4-Amino-1,8-naphthalimide(ANI) represents a valuable fluorophore from which a large number of probes have been derived in order to meet the requirements from the fields of biological sensing and imaging. In this review, the major progresses of ANI-based fluorescent probes in the past decade have been highlighted and categorized into three trends. The future development of ANI probes is also expected. This review provides a great deal of references and illuminating comments which will be helpful for the researchers designing and using fluorescent probes. 展开更多
关键词 4-Amino-1 8-naphthalimide TWO-PHOTON SUBCELLULAR ORGANELLE ENZYME Hybrid
原文传递
Theoretical Study on the Electronic Structures and Spectral Properties of 1,8-Naphthalimide Derivatives
5
作者 王艳 高慧 +2 位作者 杨平 聂光华 宋新建 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2014年第6期813-820,共8页
The molecular geometries, frontier molecular orbital properties, and absorption and emission properties of three 4-phenoxy-1,8-naphthalimide derivatives, namely 4-phenoxy-N-(2-hydroxyethyl)-1,8-naphthalimide(1),4-... The molecular geometries, frontier molecular orbital properties, and absorption and emission properties of three 4-phenoxy-1,8-naphthalimide derivatives, namely 4-phenoxy-N-(2-hydroxyethyl)-1,8-naphthalimide(1),4-(2-tert-butylphenoxy)-N-(2-hydroxyethyl)-1,8-naphthalimide(2), and 4-[2,4-di(tert-butyl)]phenoxy-N-(2-hydroxyethyl)-1,8-naphthalimide(3), are investigated by density functional theory(DFT) and time-dependent density functional theory(TD-DFT) calculations in conjunction with polarizable continuum models(PCMs). Four functionals and ten basis sets are employed for 1 to calculate the electron transition energies, which were compared with the experimental observations. Our results reveal that the B3LYP/6-311+G(d,p) method is the best choice to reproduce the experimental spectra. Moreover, the effects of substituents on the molecular geometries, electronic structures, absorption and emission spectra are also studied at the B3LYP/6-311+G(d,p) level. We find that the gap between the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO) decreases with increasing the number of tert-butyl substituents onto the phenoxy groups, suggesting red-shift of the absorption and emission bands. This is related to the increase of conjugation from 1 to 2 and 3. Our calculations are in good agreement with the experimental results. 展开更多
关键词 1 8-naphthalimide derivatives density functional theory frontier molecular orbital absorption spectrum emission spectrum
在线阅读 下载PDF
A Novel Naked-Eye and Dual-Channel Responsive Fluorescent Probe for Cu2+ Based on 3,4-Disubstituted-1,8-naphthalimide
6
作者 李辉 郝志云 +1 位作者 盂欣 朱以常 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第2期235-239,I0002,共6页
A new 3,4-disubstituted-l,8-naphthalimide derivative H1 was designed and synthesized as a selective fluorescent probe for Cu2+ over miscellaneous metM ions in aqueous media. Upon mixing with Cup-+ in CH3OH:H2O (1... A new 3,4-disubstituted-l,8-naphthalimide derivative H1 was designed and synthesized as a selective fluorescent probe for Cu2+ over miscellaneous metM ions in aqueous media. Upon mixing with Cup-+ in CH3OH:H2O (1:1, volume ratio), the increase of fluorescence intensity and a bathochromic shift of absorbance of H1 could be observed with a notable color response (changing from yellow to pink), htrthermore, Cu2+ coordinates to the probe H1 and a 1:1 metal-ligand complex was formed. 展开更多
关键词 1 8-naphthalimide Copper(II) FLUORESCENCE
在线阅读 下载PDF
Design of a 1,8-naphthalimide-based OFF-ON type bioorthogonal reagent for fluorescent imaging in live cells
7
作者 Zhuzhou Shao Chun Zhang +6 位作者 Xiaohua Zhu Yajun Wang Wenyuan Xu Yu Chen Xiaoming Wang Hailiang Zhu Yong Liang 《Chinese Chemical Letters》 SCIE CAS CSCD 2019年第12期2169-2172,共4页
A novel 1,8-naphthalimide-based OFF-ON type fluorogenic sydnone(Naph-Syd) is designed as bioorthogonal probe for imaging.Sydnone moiety efficiently quenches the native fluorescence of 1,8-naphthalimide,which can be re... A novel 1,8-naphthalimide-based OFF-ON type fluorogenic sydnone(Naph-Syd) is designed as bioorthogonal probe for imaging.Sydnone moiety efficiently quenches the native fluorescence of 1,8-naphthalimide,which can be restored with the enhancement of about 300-fold,after reacting with strained cyclooctynes to form pyrazole products(Naph-Pyr).The second-order rate constant of this bioorthogonal cycloaddition can be up to 2.5 L mol^-1s^-1,which benefits imaging of biomolecules at low concentrations in cellular environment. 展开更多
关键词 Bioorthogonal cycloaddition 1 8-naphthalimide Photophysical property Sydnone Turn-on fluorescence
原文传递
Synthesis,Crystal Structure and Fluorescence Property of N-n-butyl-4-[di(bromoethyl)]amino-1,8-naphthalimide
8
作者 叶非 王志强 +2 位作者 李萍 李关羽 付颖 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2017年第5期738-744,共7页
The halogen as a kind of alkylating reagent is used to introduce new group to realize the fluorescence sensors efficient of metal ion detection. The substituent at C-4 position was double bromine, which defined that t... The halogen as a kind of alkylating reagent is used to introduce new group to realize the fluorescence sensors efficient of metal ion detection. The substituent at C-4 position was double bromine, which defined that the halogen as an alkylating reagent should be further researched and detected for Hg2+. Therefore, the N-n-butyl-4-[di(bromoethyl)]amino-1,8-naphthalimide has been synthesized to detect some metal ions. The title compound has been prepared via substitute reaction and was characterized by IR, 1H NMR, 13 C NMR, and MS. It crystallizes in triclinic, space group P1 with a = 9.0071(18), b = 9.804(2), c = 13.073(3)A, α = 73.17(3), β = 71.73(3), γ = 62.95(3)°, Z = 2, V = 961.5(3) A3, Dc = 1.666 g/cm3, F(000) = 484, μ(Mo Kα) = 4.232 mm-1, R = 0.0429 and w R = 0.1004. The presence of intermolecular hydrogen bonds as well as π-π stacking interaction led to the stability of the compound. The fluorescence intensity was obviously lower than that of other ions when Hg2+ was added with the concentration of 1 × 10^-5 mol·L-1. 展开更多
关键词 N-n-butyl-4-[di(bromoethyl)]amino-1 8-naphthalimide SYNTHESIS single crystal fluorescence
在线阅读 下载PDF
Comparative Studies on Two 1,8-Naphthalimide Derivatives with Experimental and Theoretical Methods 被引量:1
9
作者 赵朴素 景龙 +3 位作者 李玉峰 朱园 王静 建芳芳 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2014年第5期676-686,共11页
Two 1,8-naphthalimide derivatives of 7H-benzimidazo[2,1,-a]benz[de] isoquino- lin-7-one(1) and 4-bromo-7H-benzimidazo[2,1,-a]benz[de]isoquinolin-7-one(2) have been synthesized and characterized by elemental analys... Two 1,8-naphthalimide derivatives of 7H-benzimidazo[2,1,-a]benz[de] isoquino- lin-7-one(1) and 4-bromo-7H-benzimidazo[2,1,-a]benz[de]isoquinolin-7-one(2) have been synthesized and characterized by elemental analysis, IR, 1H NMR, UV-Vis and fluorescence spectra. For the two compounds, density functional theory(DFT) calculations of the structures and natural population atomic charge analysis have been performed at the B3LYP/6-311G** level of theory. Based on Onsager reaction filed model and by using TD-DFT method at the B3LYP/6-311G** level, electron spectra of 1 and 2 with solvent effect in CHCl3 solvent have been predicted, which are in agreement with the experimental ones. Comparative studies on 1 and 2 indicate that introducing an electron-withdrawing group of Br into the 4-position of naphthalene ring in 2 does not significantly make the molecular geometry of 2 different from that of 1, but evidently changes the atomic charge redistribution, moves the positive-negative charges center and then changes the dipole moment in 2. Additionally, for compound 2, the existence of Br atom has also influenced the peak intensity and peak locations in both electron and fluorescence spectra. 展开更多
关键词 1 8-naphthalimids DFT calculation atomic charge distribution electronic spectra fluorescence spectra
在线阅读 下载PDF
靖边气田中区上古生界山^(3)_(2)-盒_(8)段储层气水特征及含气性研究 被引量:1
10
作者 陈兴官 张子为 +5 位作者 陈楠 张延斌 孟子昂 张小莉 李亚军 钟高润 《地球物理学进展》 北大核心 2025年第1期176-187,共12页
为明确鄂尔多斯盆地苏里格东南部盒_(8)段气水层核磁共振特征和含气性影响因素,利用二位核磁共振技术表征气水层特征,结合地层水、储层物性、地层各向异性、气源供给分析结果,明确了研究区盒_(8)段气水层核磁共振响应特征,分析了地层水... 为明确鄂尔多斯盆地苏里格东南部盒_(8)段气水层核磁共振特征和含气性影响因素,利用二位核磁共振技术表征气水层特征,结合地层水、储层物性、地层各向异性、气源供给分析结果,明确了研究区盒_(8)段气水层核磁共振响应特征,分析了地层水、孔隙类型、孔喉结构、地层各向异性、气源供给与储层含气性的关系.结果表明:①地层水类型主要为CaCl_(2)型,但矿化度差异性较强,分布于3669~325000 mg/L,水型全部为CaCl_(2),pH值为4.21~8.98,呈弱酸性,钠氯比[r(Na^(+))/r(Cl^(-))]均小于0.61、氯镁系数[r(Cl^(-))/r(Mg^(2+))]均大于7.0、镁钙系数[r(Mg^(2+))/r(Ca^(2+))]均小于0.69、变质系数[r(Cl^(-)-Na^(+))/r(Mg^(2+))]均大于0.47,说明地层水处于较停滞的还原状态,地层封闭性强,天然气保存良好;②盒_(8)段气水层分布关系复杂,二维核磁共振技术能有效区分气水层;③盒_(8)段储层孔隙类型以残余粒间孔和长石溶蚀孔为主,孔隙度为2.70%~14.48%,渗透率为(0.04~15.92)×10^(-2)μm^(-2),储层物性影响储层含气性,气层孔隙度、渗透率分别大于7.0%、0.2×10^(-2)μm^(-2),含气层和差气层的孔隙度、渗透率分别介于5%~9.5%、(0.02~0.7)×10^(-2)μm^(-2),干层对应的孔隙度、渗透率分别小于5%、0.1×10^(-2)μm^(-2);气层各向异性介于15%~20%,干层各向异性小于6%. 展开更多
关键词 气水层 盒_(8)段 核磁共振 含气性 各向异性
原文传递
子宫内膜癌组织肿瘤坏死因子α诱导蛋白8家族成员2、细胞增殖核抗原表达水平及与临床病理参数和预后的关系 被引量:2
11
作者 翟一阳 马韵翼 +2 位作者 翟俊英 钮红丽 王颖 《实用医学杂志》 北大核心 2025年第3期379-384,共6页
目的分析子宫内膜癌(EC)组织肿瘤坏死因子α诱导蛋白8家族成员2(TIPE2)、细胞增殖核抗原(Ki67)表达水平及与临床病理参数和预后的关系。方法回顾性收集2020年2月至2022年2月我院收治的、行手术切除的96例EC患者、120例因子宫肌瘤行子宫... 目的分析子宫内膜癌(EC)组织肿瘤坏死因子α诱导蛋白8家族成员2(TIPE2)、细胞增殖核抗原(Ki67)表达水平及与临床病理参数和预后的关系。方法回顾性收集2020年2月至2022年2月我院收治的、行手术切除的96例EC患者、120例因子宫肌瘤行子宫全切患者及120例行全子宫切除或刮宫患者的组织标本及临床资料为研究对象,分为EC组、正常子宫内膜组和不典型增生子宫内膜组,三组均随访至2023年3月28日。免疫组化法检测三组组织标本中TIPE2、Ki67表达水平,分析TIPE2、Ki67表达水平与EC组临床病理参数及预后的关系,并用受试者工作特征曲线(ROC)分析其对不良预后的诊断价值。结果EC组患者癌组织TIPE2、Ki67表达水平高于正常子宫内膜组和不典型增生子宫内膜组,且不典型增生子宫内膜组高于正常子宫内膜组(P<0.05);EC组织TIPE2、Ki67表达水平在FIGO手术病理分期为Ⅲ期、淋巴结有转移患者中高于Ⅱ期、淋巴结无转移患者(P<0.05),EC组织TIPE2表达水平在Ⅱ期、绝经及ER、PR阴性患者中高于Ⅰ期、未绝经及ER、PR阳性患者(P<0.05);EC组织Ki67表达水平在p53阳性患者中高于p53阴性患者(P<0.05),且EC组织TIPE2、Ki67表达水平之间呈正相关(r=0.569,P<0.05)。与不良预后组相比,良好预后组EC组织TIPE2、Ki67表达水平下调(P<0.05),且TIPE2、Ki67表达水平联合检测的AUC值为0.905显著大于单一检测的AUC(P<0.05),敏感度为86.67%,特异度为87.88%,预测价值较高。结论EC组织中TIPE2、Ki67呈高表达水平,两者之间具有正相关性,其高表达与临床病理特征相关,且两者联合检测对EC不良预后具有较高的预测价值。 展开更多
关键词 子宫内膜癌 肿瘤坏死因子α诱导蛋白8家族成员2 细胞增殖核抗原 临床病理 预后 诊断
暂未订购
炎调方通过Fas/Caspase-8信号通路减轻脓毒症急性胃肠损伤小鼠炎症的机制研究 被引量:1
12
作者 王帝 陈乾 +4 位作者 邓健超 王萌 王丽辉 李燕红 李华 《时珍国医国药》 北大核心 2025年第2期209-214,共6页
目的探讨炎调方调过Fas/Caspase-8信号通路减轻脓毒症急性胃肠损伤小鼠炎症的机制。方法取70只BALB/c小鼠随机分为空白组、假手术组和造模小鼠组。通过盲肠结扎穿孔术(cecum ligation and puncture,CLP)构建脓毒症急性胃肠损伤小鼠模型... 目的探讨炎调方调过Fas/Caspase-8信号通路减轻脓毒症急性胃肠损伤小鼠炎症的机制。方法取70只BALB/c小鼠随机分为空白组、假手术组和造模小鼠组。通过盲肠结扎穿孔术(cecum ligation and puncture,CLP)构建脓毒症急性胃肠损伤小鼠模型,将造模成功的小鼠随机分为模型组,炎调方低、中、高剂量组,ROCK抑制剂组。苏木素-伊红(HE)染色观察小鼠回肠组织病理学改变;ELISA法检测各组小鼠血清IL-17、IL-23水平;蛋白印迹法检测回肠组织Fas/Caspase-8信号通路蛋白Fas、FADD和Caspase-8的相对表达;TUNEL染色法检测回肠组织细胞凋亡情况。结果与空白组相比,模型组小鼠回肠组织肠黏膜萎缩明显、绒毛排列杂乱,可见断裂、脱落,上皮细胞细胞坏死脱落,炎症细胞浸润明显,小鼠血清中IL-17、IL-23水平升高(P<0.05),回肠组织中Fas、FADD和Caspase-8蛋白的表达升高(P<0.05),肠上皮细胞呈现明显的凋亡现象(P<0.05)。与模型组相比,炎调方组小鼠的回肠组织病理学改变均得到不同程度的改善,血清中IL-17、IL-23水平降低(P<0.05),且回肠组织中Fas、FADD和Caspase-8蛋白的表达降低(P<0.05),肠上皮细胞凋亡减少(P<0.05)。结论炎调方可以减轻肠黏膜组织损伤和肠道组织炎症反应,可能是通过调控Fas/Caspase-8信号通路抑制脓毒症急性胃肠损伤小鼠的肠上皮细胞凋亡来发挥作用的。 展开更多
关键词 炎调方 脓毒症急性胃肠损伤 Fas/Caspase-8信号通路 细胞凋亡
原文传递
改进YOLOv8的无人机航拍图像目标检测算法 被引量:6
13
作者 梁燕 何孝武 +1 位作者 邵凯 陈俊宏 《计算机工程与应用》 北大核心 2025年第1期121-130,共10页
针对无人机航拍图像存在多个小目标聚集、目标尺度变化大的问题,提出一种改进YOLOv8的目标检测算法TS-YOLO(tiny and scale-YOLO)。在主干部分去除冗余的特征提取层,设计了一种高效特征提取模块(efficient feature extraction module,EF... 针对无人机航拍图像存在多个小目标聚集、目标尺度变化大的问题,提出一种改进YOLOv8的目标检测算法TS-YOLO(tiny and scale-YOLO)。在主干部分去除冗余的特征提取层,设计了一种高效特征提取模块(efficient feature extraction module,EFEM),避免小目标特征消失在冗余信息中。在颈部设计了一种双重跨尺度加权特征融合方法(dual cross-scale weighted feature-fusion,DCWF),融合多尺度信息的同时抑制噪声干扰,提升特征表达能力。通过构建一种参数共享检测头(parameter-shared detection header,PSDH),使回归和分类任务实现参数共享,保证检测精度的同时有效降低了模型的参数量。所提模型在VisDrone-2019数据集上的精度(P)和召回率(R)分别达到54.0%、42.5%;相比于原始YOLOv8s模型,mAP50提高了5.0个百分点,达到44.5%,且参数量减少了55.8%,仅有4.94×106;在DOTAv1.0遥感数据集上,mAP50达到71.9%,仍具有较好的泛化能力。 展开更多
关键词 目标检测 无人机航拍图像 YOLOv8 小目标 特征融合
在线阅读 下载PDF
基于改进YOLOv8s的轻量级果园李子检测方法 被引量:3
14
作者 张冬妍 陈诺 +2 位作者 张淇 吴晨旭 张榄翔 《农业工程学报》 北大核心 2025年第1期154-160,共7页
为了解决果园李子受枝叶和果实遮蔽、环境变化等因素影响,难以准确检测的问题,该研究提出了一种基于改进YOLOv8s的轻量级果园李子检测模型。首先,采用自设计主干网络Faster-EMA缩减模型复杂度、提高检测精度。其次,引入焦点调制网络(foc... 为了解决果园李子受枝叶和果实遮蔽、环境变化等因素影响,难以准确检测的问题,该研究提出了一种基于改进YOLOv8s的轻量级果园李子检测模型。首先,采用自设计主干网络Faster-EMA缩减模型复杂度、提高检测精度。其次,引入焦点调制网络(focal modulation)替换原模型中的SPPF模块增强特征融合能力,丰富特征提取的语义信息;最后,引入参数共享策略并实现轻量级检测头LDetect,满足了低功耗嵌入式设备部署需求。试验结果表明,优化后模型的平均检测精度达到97.2%,与原模型相比,检测精度提高了7.4个百分点;模型计算量降低了44.8%;模型参数数量减小了25.8%;部署在边缘计算设备Jetson Nano 4GB上,检测帧率达到了48.3帧/s。该研究所提出的方法能有效的解决复杂背景下果园李子的智能化检测,有助于促进李子智能化采摘技术的发展。 展开更多
关键词 目标检测 YOLOv8 轻量化 李子 LDetect
在线阅读 下载PDF
基于改进YOLOv8的果园复杂环境下苹果检测模型研究 被引量:2
15
作者 岳有军 漆潇 +1 位作者 赵辉 王红君 《南京信息工程大学学报》 北大核心 2025年第1期31-41,共11页
为了使采摘机器人能够在果园复杂环境下(如不同光照条件、叶子遮挡、密集的苹果群和超远视距等场景)对成熟程度各异的苹果果实进行快速且精确的检测,本文提出一种基于改进YOLOv8的苹果果实检测模型.首先,将EMA注意力机制模块集成到YOLOv... 为了使采摘机器人能够在果园复杂环境下(如不同光照条件、叶子遮挡、密集的苹果群和超远视距等场景)对成熟程度各异的苹果果实进行快速且精确的检测,本文提出一种基于改进YOLOv8的苹果果实检测模型.首先,将EMA注意力机制模块集成到YOLOv8模型中,使模型更加关注待检测果实区域,抑制背景和枝叶遮挡等一般特征信息,提高被遮挡果实的检测准确率;其次,使用提取特征更加高效的三支路DWR模块对原始C2f模块进行替换,通过多尺度特征融合方法提高小目标检测能力;同时结合DAMO-YOLO的思想,对原始YOLOv8颈部进行重构,实现高层语义和低层空间特征的高效融合;最后,使用Inner-SIoU损失函数对模型进行优化,提高识别精度.在复杂的果园环境中,以苹果作为检测对象,实验结果表明:本文所提算法在测试集下的查准率、召回率、mAP_(0.5)、mAP_(0.5~0.95)以及F1分数分别达到86.1%、89.2%、94.0%、64.4%和87.6%,改进后的算法在大部分指标上均优于原始模型.在不同数量果实场景下的对比实验结果表明,该方法具有优异的鲁棒性. 展开更多
关键词 模式识别 深度学习 目标检测 YOLOv8
在线阅读 下载PDF
基于YOLOv8目标检测器的对抗攻击方案设计 被引量:3
16
作者 李秀滢 赵海淇 +2 位作者 陈雪松 张健毅 赵成 《信息安全研究》 北大核心 2025年第3期221-230,共10页
目前,基于人工智能目标检测技术的摄像头得到了广泛的应用.而在现实世界中,基于人工智能的目标检测模型容易受到对抗样本攻击.现有的对抗样本攻击方案都是针对早版本的目标检测模型而设计的,利用这些方案去攻击最新的YOLOv8目标检测器... 目前,基于人工智能目标检测技术的摄像头得到了广泛的应用.而在现实世界中,基于人工智能的目标检测模型容易受到对抗样本攻击.现有的对抗样本攻击方案都是针对早版本的目标检测模型而设计的,利用这些方案去攻击最新的YOLOv8目标检测器并不能取得很好的攻击效果.为解决这一问题,针对YOLOv8目标检测器设计了一个全新的对抗补丁攻击方案.该方案在最小化置信度输出的基础上,引入了EMA注意力机制强化补丁生成时的特征提取,进而增强了攻击效果.实验证明该方案具有较优异的攻击效果和迁移性,将该方案形成的对抗补丁打印在衣服上进行验证测试,同样获得较优异的攻击效果,表明该方案具有较强的实用性. 展开更多
关键词 深度学习 对抗样本 YOLOv8 目标检测 对抗补丁
在线阅读 下载PDF
基于改进YOLO v8n网络的番茄成熟度实时检测算法 被引量:6
17
作者 任晶秋 万恩晗 +2 位作者 单蜜 张光华 卢为党 《农业机械学报》 北大核心 2025年第3期374-382,450,共10页
为应对番茄采摘面临的果农老龄化、劳动力短缺和人工成本上涨等挑战,解决在复杂果园环境下番茄采摘机器人视觉系统成熟度检测精度低和实例分割不准确等问题,本文提出一种基于改进YOLO v8n网络的番茄成熟度实时检测算法。首先,通过在YOLO... 为应对番茄采摘面临的果农老龄化、劳动力短缺和人工成本上涨等挑战,解决在复杂果园环境下番茄采摘机器人视觉系统成熟度检测精度低和实例分割不准确等问题,本文提出一种基于改进YOLO v8n网络的番茄成熟度实时检测算法。首先,通过在YOLO v8n网络中引入通道嵌入位置注意力模块和改进大核卷积块注意力模块,能够在浅层网络保留番茄目标位置信息,建立目标区域之间的长距离依赖关系,从而增加YOLO v8n网络对显著番茄特征的关注。然后,在LaboroTomato数据集上进行了对比实验,改进YOLO v8n相较于原YOLO v8n网络,检测和分割的mAP@50和mAP@50-95分别提高0.4、1.4个百分点和0.3、1.2个百分点。最后,实现了改进YOLO v8n网络在低成本、低算力和低功耗的Jetson Nano平台上的轻量化部署,模型内存占用量由满溢减少到2.4 GB,推理速度加倍。该研究可为番茄采摘机器人在复杂场景下实时、准确检测番茄成熟度提供技术支撑。 展开更多
关键词 番茄成熟度 目标检测 YOLO v8n 注意力模块 轻量化 Jetson Nano
在线阅读 下载PDF
改进YOLOv8的光伏电池缺陷检测算法 被引量:2
18
作者 杨丽 杨晨晨 +2 位作者 杨耿煌 段海龙 邓靖威 《电子测量技术》 北大核心 2025年第1期92-99,共8页
针对光伏电池缺陷检测在复杂背景下存在的误检、漏检等问题,提出了一种基于改进YOLOv8的光伏电池缺陷检测算法。首先,采用双向特征金字塔网络作为特征融合机制,通过自顶向下和自底向上的路径,实现多尺度特征的有效融合;其次,在颈部网络... 针对光伏电池缺陷检测在复杂背景下存在的误检、漏检等问题,提出了一种基于改进YOLOv8的光伏电池缺陷检测算法。首先,采用双向特征金字塔网络作为特征融合机制,通过自顶向下和自底向上的路径,实现多尺度特征的有效融合;其次,在颈部网络引入上下文聚合模块,使用不同空洞卷积速率的空洞卷积获取不同感受野的上下文信息,帮助模型更精准地识别微小目标,进而提升模型的目标检测性能;最后,优化边界框损失函数,并不断调试其权重因子,提高模型的收敛速度与效率。实验结果表明,与YOLOv8算法检测网络相比,本文算法的召回率和平均精确度均值分别提高了10.4%、1.8%,检测帧率达到270 fps,保证了实时检测和后续部署的轻量化要求,改进后的算法能在复杂背景下对光伏电池的缺陷进行鲁棒检测。 展开更多
关键词 光伏电池 缺陷检测 YOLOv8 注意力机制 损失函数
原文传递
Selective and Sensitive Fluorescent Chemosensors for Cu2+ Ion Based upon Bis-1,8-naphthalimide Dyads 被引量:1
19
作者 Dai,Huiling Xu,Hui 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2012年第2期267-272,共6页
A series of new fluorescent chemosensors 5a--5e, composed of two aminonaphthalimide fluorophores and 2,6-bis((N-aminoalkyl)aminocarboxy)pyridines, were prepared, characterized, and their fluorescent properties to-... A series of new fluorescent chemosensors 5a--5e, composed of two aminonaphthalimide fluorophores and 2,6-bis((N-aminoalkyl)aminocarboxy)pyridines, were prepared, characterized, and their fluorescent properties to- wards heavy and transition metal (HTM) ions were investigated. Chemosensors 5e--Se exhibited high selectivity and sensitivity for Cu2+ ion over other HTM ions with fluorescent quenching (green to colourless). It clearly demonstrated that the length of the linkers (diamines) between the aminonaphthalimides and 2,6-dicarboxypyridine of 5a--Se was very important for their sensitivity and selectivity for Cu2~ ion over other HTM ions. 展开更多
关键词 fluorescence sensors 1 8-naphthalimide metal ion SELECTIVITY
原文传递
LMUAV-YOLOv8:低空无人机视觉目标检测轻量化网络 被引量:6
20
作者 董一兵 曾辉 侯少杰 《计算机工程与应用》 北大核心 2025年第3期94-110,共17页
针对低空无人机目标检测面临目标尺度变化大、小目标容易漏检和误检的挑战,发展了一种融合多尺度特征的目标检测轻量化网络(LMUAV-YOLOv8),通过开展消融和对比实验,验证了算法的有效性和先进性,并借助类激活图,对模型的决策过程进行了... 针对低空无人机目标检测面临目标尺度变化大、小目标容易漏检和误检的挑战,发展了一种融合多尺度特征的目标检测轻量化网络(LMUAV-YOLOv8),通过开展消融和对比实验,验证了算法的有效性和先进性,并借助类激活图,对模型的决策过程进行了解释。设计了一种轻量化的特征融合网络(UAV_RepGFPN),提出新的特征融合路径以及特征融合模块DBB_GELAN,降低参数量和计算量的同时,提高特征融合网络的性能。使用部分卷积(PConv)和三重注意力机制(Triplet Attention)构建特征提取模块(FTA_C2f),并引入ADown下采样模块,通过对输入特征图维度的重新排列和细粒度调整,以提升模型中深层网络对空间特征的捕捉能力,并进一步降低参数量和计算量。优化YOLOv9的可编程梯度信息(programmable gradient information,PGI)策略,设计基于上下文引导(Context_guided)的可逆架构,并额外生成三个辅助检测头,提出UAV_PGI可编程梯度方法,避免传统深度监督中多路径特征集成可能导致的语义信息损失。为了验证模型的有效性及泛化能力,在VisDrone 2019测试集上开展了对比实验,结果显示,与YOLOv8s相比,LMUAV-YOLOv8s的准确度、召回率、mAP@0.5和mAP@0.5:0.95等指标分别提升了4.2、3.9、5.1和3.0个百分点,同时参数量减少了63.9%,计算量仅增加0.4 GFLOPs,实现了检测性能与资源消耗的良好平衡。基于NVIDIA Jetson Xavier NX嵌入式平台的推理实验结果显示:与基线模型相比,该算法能够在满足实时检测要求的条件下,获得更高的检测精度,对于无人机实时目标检测场景具有较好的适用性。借助类激活图,对算法的决策过程进行了可视化分析,结果表明,该模型具备更优异的小尺度特征提取和高分辨率处理能力。 展开更多
关键词 小目标检测 多尺度 轻量化 YOLOv8 可编程梯度信息
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部