期刊文献+
共找到747篇文章
< 1 2 38 >
每页显示 20 50 100
Target layer state estimation in multi-layer complex dynamical networks considering nonlinear node dynamics
1
作者 吴亚勇 王欣伟 蒋国平 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期245-252,共8页
In many engineering networks, only a part of target state variables are required to be estimated.On the other hand,multi-layer complex network exists widely in practical situations.In this paper, the state estimation ... In many engineering networks, only a part of target state variables are required to be estimated.On the other hand,multi-layer complex network exists widely in practical situations.In this paper, the state estimation of target state variables in multi-layer complex dynamical networks with nonlinear node dynamics is studied.A suitable functional state observer is constructed with the limited measurement.The parameters of the designed functional observer are obtained from the algebraic method and the stability of the functional observer is proven by the Lyapunov theorem.Some necessary conditions that need to be satisfied for the design of the functional state observer are obtained.Different from previous studies, in the multi-layer complex dynamical network with nonlinear node dynamics, the proposed method can estimate the state of target variables on some layers directly instead of estimating all the individual states.Thus, it can greatly reduce the placement of observers and computational cost.Numerical simulations with the three-layer complex dynamical network composed of three-dimensional nonlinear dynamical nodes are developed to verify the effectiveness of the method. 展开更多
关键词 multi-layer complex dynamical network nonlinear node dynamics target state estimation functional state observer
下载PDF
MicroRNA-451 from Human Umbilical Cord-Derived Mesenchymal Stem Cell Exosomes Inhibits Alveolar Macrophage Autophagy via Tuberous Sclerosis Complex 1/Mammalian Target of Rapamycin Pathway to Attenuate Burn-Induced Acute Lung Injury in Rats
2
作者 Zhigang Jia Lin Li +5 位作者 Peng Zhao Guo Fei Shuangru Li Qinqin Song Guangpeng Liu Jisong Liu 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第9期1030-1043,共14页
Objective Our previous studies established that microRNA(miR)-451 from human umbilical cord mesenchymal stem cell-derived exosomes(hUC-MSC-Exos)alleviates acute lung injury(ALI).This study aims to elucidate the mechan... Objective Our previous studies established that microRNA(miR)-451 from human umbilical cord mesenchymal stem cell-derived exosomes(hUC-MSC-Exos)alleviates acute lung injury(ALI).This study aims to elucidate the mechanisms by which miR-451 in hUC-MSC-Exos reduces ALI by modulating macrophage autophagy.Methods Exosomes were isolated from hUC-MSCs.Severe burn-induced ALI rat models were treated with hUC-MSC-Exos carrying the miR-451 inhibitor.Hematoxylin-eosin staining evaluated inflammatory injury.Enzyme-linked immunosorbnent assay measured lipopolysaccharide(LPS),tumor necrosis factor-α,and interleukin-1βlevels.qRT-PCR detected miR-451 and tuberous sclerosis complex 1(TSC1)expressions.The regulatory role of miR-451 on TSC1 was determined using a dual-luciferase reporter system.Western blotting determined TSC1 and proteins related to the mammalian target of rapamycin(mTOR)pathway and autophagy.Immunofluorescence analysis was conducted to examine exosomes phagocytosis in alveolar macrophages and autophagy level.Results hUC-MSC-Exos with miR-451 inhibitor reduced burn-induced ALI and promoted macrophage autophagy.MiR-451 could be transferred from hUC-MSCs to alveolar macrophages via exosomes and directly targeted TSC1.Inhibiting miR-451 in hUC-MSC-Exos elevated TSC1 expression and inactivated the mTOR pathway in alveolar macrophages.Silencing TSC1 activated mTOR signaling and inhibited autophagy,while TSC1 knockdown reversed the autophagy from the miR-451 inhibitor-induced.Conclusion miR-451 from hUC-MSC exosomes improves ALI by suppressing alveolar macrophage autophagy through modulation of the TSC1/mTOR pathway,providing a potential therapeutic strategy for ALI. 展开更多
关键词 Acute lung injury Human umbilical cord mesenchymal stem cell-derived exosomes MicroRNA-451 Tuberous sclerosis complex 1 Mammalian target of rapamycin pathway AUTOPHAGY
下载PDF
Simulation research on scattering characteristics by complex targets 被引量:4
3
作者 Guo Kunyi Sheng Xinqing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2007年第4期685-691,共7页
A simulation approach based on a full-wave numerical method is presented to study electromagnetic characteristics by complex targets. How to validate simulation results is considered thoroughly under no analytical and... A simulation approach based on a full-wave numerical method is presented to study electromagnetic characteristics by complex targets. How to validate simulation results is considered thoroughly under no analytical and measured data, where a double-check criterion is designed for our simulation approach. As an example, the scattering of F-117A is studied by using our simulation approach under all polarizations, different frequency bands, incident and scattering directions, etc., some of which, such as cross-polarization, bistatic RCS, have not been considered in the previous literature. 展开更多
关键词 electromagnetic characteristics SIMULATION complex targets hybrid FE-BI-MLFMA.
下载PDF
Development and evaluation of vinpocetine inclusion complex for brain targeting 被引量:2
4
作者 Jiaojiao Ding Jinfeng Li Shirui Mao 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2015年第2期114-120,共7页
The objective of this paper is to prepare vinpocetine(VIN)inclusion complex and evaluate its brain targeting effect after intranasal administration.In the present study,VIN inclusion complex was prepared in order to i... The objective of this paper is to prepare vinpocetine(VIN)inclusion complex and evaluate its brain targeting effect after intranasal administration.In the present study,VIN inclusion complex was prepared in order to increase its solubility.Stability constant(Kc)was used for host selection.Factors influencing properties of the inclusion complex was investigated.Formation of the inclusion complex was identified by solubility study and DSC analysis.The brain targeting effect of the complex after intranasal administration was studied in rats.It was demonstrated that properties of the inclusion complex was mainly influenced by cyclodextrin type,organic acids type,system pH and host/guest molar ratio.Multiple component complexes can be formed by the addition of citric acid,with solubility improved for more than 23 times.Furthermore,In vivo study revealed that after intranasal administration,the absolute bioavailability of vinpocetine inclusion complex was 88%.Compared with intravenous injection,significant brain targeting effect was achieved after intranasal delivery,with brain targeting index 1.67.In conclusion,by intranasal administration of VIN inclusion complex,a fast onset of action and good brain targeting effect can be achieved.Intranasal route is a promising approach for the treatment of CNS diseases. 展开更多
关键词 VINPOCETINE Hydroxypropyl-b-cyclodextrin Citric acid Inclusion complex Brain targeting
下载PDF
Role of mammalian target of rapamycin complex 2 in primary and secondary liver cancer 被引量:1
5
作者 Katharina Joechle Jessica Guenzle +4 位作者 Claus Hellerbrand Pavel Strnad Thorsten Cramer Ulf Peter Neumann Sven Arke Lang 《World Journal of Gastrointestinal Oncology》 SCIE 2021年第11期1632-1647,共16页
The mammalian target of rapamycin(mTOR)acts in two structurally and functionally distinct protein complexes,mTOR complex 1(mTORC1)and mTOR complex 2(mTORC2).Upon deregulation,activated mTOR signaling is associated wit... The mammalian target of rapamycin(mTOR)acts in two structurally and functionally distinct protein complexes,mTOR complex 1(mTORC1)and mTOR complex 2(mTORC2).Upon deregulation,activated mTOR signaling is associated with multiple processes involved in tumor growth and metastasis.Compared with mTORC1,much less is known about mTORC2 in cancer,mainly because of the unavailability of a selective inhibitor.However,existing data suggest that mTORC2 with its two distinct subunits Rictor and mSin1 might play a more important role than assumed so far.It is one of the key effectors of the PI3K/AKT/mTOR pathway and stimulates cell growth,cell survival,metabolism,and cytoskeletal organization.It is not only implicated in tumor progression,metastasis,and the tumor microenvironment but also in resistance to therapy.Rictor,the central subunit of mTORC2,was found to be upregulated in different kinds of cancers and is associated with advanced tumor stages and a bad prognosis.Moreover,AKT,the main downstream regulator of mTORC2/Rictor,is one of the most highly activated proteins in cancer.Primary and secondary liver cancer are major problems for current cancer therapy due to the lack of specific medical treatment,emphasizing the need for further therapeutic options.This review,therefore,summarizes the role of mTORC2/Rictor in cancer,with special focus on primary liver cancer but also on liver metastases. 展开更多
关键词 Mammalian target of rapamycin Mammalian target of rapamycin complex 2 RICTOR Liver cancer Liver metastases Hepatocellular carcinoma Cholangiocellular carcinoma
下载PDF
Mammalian target of rapamycin complex 1 as an inducer of neurotrophic factors in dopaminergic neurons 被引量:1
6
作者 Sang Ryong Kim 《Neural Regeneration Research》 SCIE CAS CSCD 2014年第23期2036-2037,共2页
The defining neuropathological feature of Parkinson's disease (PD) is the loss of nigrostriatal dopaminergic (DA) projections. This results in striatal dopamine levels and a biochemical reduction of movement diso... The defining neuropathological feature of Parkinson's disease (PD) is the loss of nigrostriatal dopaminergic (DA) projections. This results in striatal dopamine levels and a biochemical reduction of movement disorders, such as a tremor at rest, rigidity of the limbs, bradykinesia, and postural instability (Kim et al., 2011; Kim et al., 2012; Burke and O'Malley, 2013; Leem et al., 2014; Namet al., 2014). 展开更多
关键词 RHEB Mammalian target of rapamycin complex 1 as an inducer of neurotrophic factors in dopaminergic neurons GDNF BDNF
下载PDF
Support vector regression model for complex target RCS predicting
7
作者 Wang Gu Chen Weishi Miao Jungang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第1期65-68,共4页
The electromagnetic scattering computation has developed rapidly for many years; some computing problems for complex and coated targets cannot be solved by using the existing theory and computing models. A computing m... The electromagnetic scattering computation has developed rapidly for many years; some computing problems for complex and coated targets cannot be solved by using the existing theory and computing models. A computing model based on data is established for making up the insufficiency of theoretic models. Based on the "support vector regression method", which is formulated on the principle of minimizing a structural risk, a data model to predicate the unknown radar cross section of some appointed targets is given. Comparison between the actual data and the results of this predicting model based on support vector regression method proved that the support vector regression method is workable and with a comparative precision. 展开更多
关键词 radar cross section complex target coated target support vector regression.
下载PDF
SCTE: RCS Prediction System for ComplexTarget and Interaction with Environment
8
作者 Cao Qin-feng Lu Shu Xu Peng-gen 《Wuhan University Journal of Natural Sciences》 CAS 1999年第3期299-303,共5页
A RCS prediction system named SCTE (Scattering from Complex Target and Environment) for calculating high-frequency electromagnetic scattering from complex target within complex environment is presented. The scattering... A RCS prediction system named SCTE (Scattering from Complex Target and Environment) for calculating high-frequency electromagnetic scattering from complex target within complex environment is presented. The scattering body is described by Computer-Aided-Design (CAD) representations in which the complex body is modeled as NURBS (Non-Uniform Rational B-spline) surfaces. The complex environment (rough surface of sea or ground) is also carefully considered by using fractal function. Scattering fields are calculated by using physical optics and the equivalent currents methods. There is a good agreement between the present results and that from measurements which demonstrates the accuracy of this system. 展开更多
关键词 RCS complex target EM scattering
下载PDF
Attractive target wave patterns in complex networks consisting of excitable nodes
9
作者 张立升 廖旭红 +2 位作者 弥元元 钱郁 胡岗 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第7期171-182,共12页
This review describes the investigations of oscillatory complex networks consisting of excitable nodes, focusing on the target wave patterns or say the target wave attractors. A method of dominant phase advanced drivi... This review describes the investigations of oscillatory complex networks consisting of excitable nodes, focusing on the target wave patterns or say the target wave attractors. A method of dominant phase advanced driving (DPAD) is introduced to reveal the dynamic structures in the networks supporting osciUations, such as the oscillation sources and the main excitation propagation paths from the sources to the whole networks. The target center nodes and their drivers are regarded as the key nodes which can completely determine the corresponding target wave patterns. Therefore, the center (say node A) and its driver (say node B) of a target wave can be used as a label, (A, B), of the given target pattern. The label can give a clue to conveniently retrieve, suppress, and control the target waves. Statistical investigations, both theoretically from the label analysis and numerically from direct simulations of network dynamics, show that there exist huge numbers of target wave attractors in excitable complex networks if the system size is large, and all these attractors can be labeled and easily controlled based on the information given by the labels. The possible applications of the physical ideas and the mathematical methods about multiplicity and labelability of attractors to memory problems of neural networks are briefly discussed. 展开更多
关键词 dominant phase advanced driving method complex networks labelable attractors target wavepatterns
下载PDF
An Approach to RCS Computation for Complex Targets
10
作者 Zhao Weijiang & Wang Maoguang Xidian University, Xi’an 710071, P. R. China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1997年第4期56-60,共5页
A practical approach for calculating the RCS (Radar Cross Section) of complex targets modeled with wire-grid-frame is presented. A way for generating a polyhedron model (facet-wedge model) with the wire-grid-frame dat... A practical approach for calculating the RCS (Radar Cross Section) of complex targets modeled with wire-grid-frame is presented. A way for generating a polyhedron model (facet-wedge model) with the wire-grid-frame data is described. For storing and reading the data of the polyhedron model in an easy way, a data structure is given. 展开更多
关键词 Radar cross section Geometry modeling complex target.
下载PDF
In vitro antitumor activity and targeted sites of two novel platinum-based(II) complexes on SW620 colon cancer cell line
11
作者 Rui Li Baolin Liu Hongzhuan Yin Feng Xu Qi Su 《The Chinese-German Journal of Clinical Oncology》 CAS 2011年第9期510-516,共7页
Objective:The aim of our study was to evaluate the in vitro antitumor activity of two novel platinum-based(II) complexes(2.3-pyridinedicarboxylic acid dehydrate platinum and 2.3-pyrazinedicarboxylic acid dehydrate pla... Objective:The aim of our study was to evaluate the in vitro antitumor activity of two novel platinum-based(II) complexes(2.3-pyridinedicarboxylic acid dehydrate platinum and 2.3-pyrazinedicarboxylic acid dehydrate platinum),which were concurrently provided with hydrophilic carboxyl group and lipophilic pyrazinyl or pyridyl group,on SW620 colorectal cancer cell line and the impact of the two compounds on the cell cycle and apoptosis of the cells when compared with the oxaliplatin,desiring the new ligand combined with hydrophilic and lipophilic properties would facilitate the transportation and transmembrane of the drugs,showing a better antitumor activity.Methods:After SW620 cells were treated with different doses of the three platinum-based agents for 24,48 and 72 h,the cell proliferation inhibition rate was determined using methyl thiazolyl tetrazolium(MTT) assay;the morphology of cells were evaluated under inverted microscope;the changes in cell cycle were determined using flow cytometry;the percent apoptosis was measured using Annexin V/PI double staining and the micromorphology of the cells after drug exposure was evaluated using scanning electron microscopy.Results:The evaluation on the proliferation inhibition rate revealed that the three platinum-based agents inhibited the SW620 cells in a time-and dose-dependent manner and showed different strengths as pyridine > pyrazine > Oxa.Under optical microscope,the morphological changes such as cell shrinkage,round cells and dead cells were frequently observed after drug exposure.Cell cycle determination showed that all of the three agents could function to block the cells converting from phase S to phase G2M.Apoptosis evaluation revealed that the three agents promoted the apoptosis of SW620 cells in a time-and dose-dependent manner and showed different strengths as pyridine > pyrazine > Oxa.Typical early and late apoptotic morphological changes could be detected during electron microscopy.Conclusion:The two novel platinum-based(II) complexes showed a stronger antitumor effect on SW620 cells than oxaliplatin,with the targeted site at a certain phase of cell cycle and apoptosis. 展开更多
关键词 platinum-based(II) complex SW620 cell line antitumor activity targeted site
下载PDF
3,6-dichlorobenzo[b]thiophene-2-carboxylic acid alleviates ulcerative colitis by suppressing mammalian target of rapamycin complex 1 activation and regulating intestinal microbiota
12
作者 Qiong-Zi He Peng Wei +5 位作者 Jun-Zhi Zhang Tong-Tong Liu Kun-Qun Shi Huan-Huan Liu Jing-Wei Zhang Shi-Jia Liu 《World Journal of Gastroenterology》 SCIE CAS 2022年第46期6522-6536,共15页
BACKGROUND 3,6-dichlorobenzo[b]thiophene-2-carboxylic acid(BT2)is a benzothiophene carboxylate derivative that can suppress the catabolism of branched-chain amino acid(BCAA)-associated mammalian target of rapamycin co... BACKGROUND 3,6-dichlorobenzo[b]thiophene-2-carboxylic acid(BT2)is a benzothiophene carboxylate derivative that can suppress the catabolism of branched-chain amino acid(BCAA)-associated mammalian target of rapamycin complex 1(mTORC1)activation.Previous studies have demonstrated the therapeutic effects of BT2 on arthritis,liver cancer,and kidney injury.However,the effects of BT2 on ulcerative colitis(UC)are unknown.AIM To investigate the anti-UC effects of BT2 and the underlying mechanism.METHODS Mouse UC models were created through the administration of 3.5%dextran sodium sulfate(DSS)for 7 d.The mice in the treated groups were administered salazosulfapyridine(300 mg/kg)or BT2(20 mg/kg)orally from day 1 to day 7.At the end of the study,all of the mice were sacrificed,and colon tissues were removed for hematoxylin and eosin staining,immunoblot analyses,and immunohistochemical assays.Cytokine levels were measured by flow cytometry.The contents of BCAAs including valine,leucine,and isoleucine,in mouse serum were detected by liquid chromatography-tandem mass spectrometry,and the abundance of intestinal flora was analyzed by 16S ribosomal DNA sequencing.RESULTS Our results revealed that BT2 significantly ameliorated the inflammatory symptoms and pathological damage induced by DSS in mice.BT2 also reduced the production of the proinflammatory cytokines interleukin 6(IL-6),IL-9,and IL-2 and increased the anti-inflammatory cytokine IL-10 level.In addition,BT2 notably improved BCAA catabolism and suppressed mTORC1 activation and cyclooxygenase-2 expression in the colon tissues of UC mice.Furthermore,highthroughput sequencing revealed that BT2 restored the gut microbial abundance and diversity in mice with colitis.Compared with the DSS group,BT2 treatment increased the ratio of Firmicutes to Bacteroidetes and decreased the abundance of Enterobacteriaceae and Escherichia-Shigella.CONCLUSION Our results indicated that BT2 significantly ameliorated DSS-induced UC and that the latent mechanism involved the suppression of BCAA-associated mTORC1 activation and modulation of the intestinal flora. 展开更多
关键词 3 6-dichlorobenzo[b]thiophene-2-carboxylic acid Ulcerative colitis Mechanistic target of rapamycin complex 1 Intestinal flora Dextran sodium sulfate Cyclooxygenase-2
下载PDF
复杂背景下基于YOLOv7-tiny的图像目标检测算法 被引量:1
13
作者 薛珊 安宏宇 +1 位作者 吕琼莹 曹国华 《红外与激光工程》 EI CSCD 北大核心 2024年第1期261-272,共12页
“黑飞”无人机一旦带有炸弹等物品,会对人们带来威胁。对在公园、游乐场、学校等复杂背景下“黑飞”的无人机进行目标检测是十分必要的。前沿算法YOLOv7-tiny属于轻量级网络,具有更小的网络结构和参数,更适合检测小目标,但在识别小目... “黑飞”无人机一旦带有炸弹等物品,会对人们带来威胁。对在公园、游乐场、学校等复杂背景下“黑飞”的无人机进行目标检测是十分必要的。前沿算法YOLOv7-tiny属于轻量级网络,具有更小的网络结构和参数,更适合检测小目标,但在识别小目标无人机时出现特征提取能力弱、回归损失大、检测精度低的问题;针对此问题,提出了一种基于YOLOv7-tiny改进的无人机图像目标检测算法YOLOv7-drone。首先,建立无人机图像数据集;其次,设计一种新的注意力机制模块SMSE嵌入到特征提取网络中,增强对复杂背景下无人机目标的关注度;然后,在主干网络中融入RFB结构,扩大特征层的感受野,丰富特征信息以增强特征提取的鲁棒性;然后,改进网络中的特征融合机制,通过新增小目标检测层,增加对小尺度目标的检测精度;然后,改变损失函数提高模型的收敛速度,减少损失以增强模型的鲁棒性;最后,引入可变形卷积(Deformable convolution, DCN),更好的根据目标本身形状进行特征提取,提升了检测精度。在PASCAL VOC公共数据集上进行对比实验,结果表明改进后的算法YOLO7-drone相比于YOLOv7-tiny,平均精度(map@0.5)提升了6%;在自制无人机数据集上进行实验,结果表明YOLOv7-drone与原算法相比,平均精度(map@0.5)提高了6.1%,并且检测速度为72帧/s;与YOLOv5l、YOLOv7目标检测算法进行对比实验,结果表明改进后的算法在平均精度(map@0.5)上分别高于对比算法4%、3.1%,验证了文中算法的可行性。 展开更多
关键词 目标检测 复杂背景 注意力机制 小目标检测
下载PDF
大规模个性化定制的价值涌现原理——价值共创的新形态 被引量:1
14
作者 肖人彬 侯俊东 +2 位作者 鲁效平 胡鹏 秦施政 《南昌工程学院学报》 CAS 2024年第2期1-8,共8页
依托生产模式的三维结构框架,从复杂性视角,针对手工生产、大规模生产、大规模定制、大规模个性化和大规模个性化定制等主要生产模式,分析其中从价值交易到价值共创再到价值涌现的价值生成演化历程,提炼出客户维、生产维和服务维3个维... 依托生产模式的三维结构框架,从复杂性视角,针对手工生产、大规模生产、大规模定制、大规模个性化和大规模个性化定制等主要生产模式,分析其中从价值交易到价值共创再到价值涌现的价值生成演化历程,提炼出客户维、生产维和服务维3个维度下的价值生成路径。基于局部作用导致整体涌现的系统科学观念,揭示出大规模个性化定制的价值涌现原理,明确了该原理的基本内涵。人单合一是大规模个性化定制的一种具体实现,其价值创造规律遵从价值涌现原理。生态价值是人单合一价值创造的源泉,海尔的超模块平台组织结构可实现人单合一中的价值涌现。大规模个性化定制的价值生成过程具有涌现性特征,它以价值涌现的方式表现出来,是价值共创的一种新形态。 展开更多
关键词 大规模个性化定制 价值涌现 价值共创 人单合一 系统科学 复杂性 精准服务 生态型企业
下载PDF
中药复方的现代基础研究进展述评
15
作者 杨洪军 李贤煜 +6 位作者 陈鹏 张晶晶 吴宏伟 郭娜 郭非非 廖星 毕明刚 《中国科学基金》 CSCD 北大核心 2024年第3期387-395,共9页
中药复方的现代基础研究是中药现代化发展的必经之路。本文从中药复杂作用模式解析研究策略与方法、中药直接靶点发现技术与应用、系统生物学驱动的中药复杂作用解析三个方面,对中药复方的现代基础研究进行综述,并对其未来发展进行展望。
关键词 中药复方 现代基础研究 靶点发现 系统生物学 复杂作用解析
下载PDF
复杂水文微弱多目标激光探测仿真与实验
16
作者 宗思光 杨劭鹏 +3 位作者 张鑫 彭丹 段子科 陈报 《中国光学(中英文)》 EI CAS CSCD 北大核心 2024年第3期560-571,共12页
为了探究在近岸复杂水体中激光探测对微弱目标的探测能力,研究水质、目标特征、目标距离对水下激光探测的影响具有重要理论和应用价值。论文建立了水下微弱目标激光探测模型,采用蒙特卡洛仿真验证了不同浊度微弱多目标激光探测性能,模... 为了探究在近岸复杂水体中激光探测对微弱目标的探测能力,研究水质、目标特征、目标距离对水下激光探测的影响具有重要理论和应用价值。论文建立了水下微弱目标激光探测模型,采用蒙特卡洛仿真验证了不同浊度微弱多目标激光探测性能,模拟了不同距离下微弱目标的激光后向散射回波信号,对多个不同反射系数的目标后向散射回波特性进行了分析。同时设计并研制了灵巧便携式水下微弱目标激光探测系统,进行了实验室及外场湖泊环境下的多目标探测、测距测试验证。在浊度为12.87 NTU的近岸湖泊水域,该系统可在10 m范围内对3~4个直径为80~400μm的不同低反射系数的混合小目标进行有效探测,平均测量误差为±0.11 m,与理论仿真结果一致。本文研究结果可为蓝绿激光水下多微弱目标探测链路计算、系统设计及参数优化提供参考,可以支撑近海浑浊水体下水下障碍物激光探测工程实践。 展开更多
关键词 激光探测与测距 微弱多目标 复杂水文 蒙特卡洛
下载PDF
受体相互作用蛋白激酶1调节癌症进展和免疫反应的研究现状
17
作者 张勇 李伟宏 +3 位作者 程志鹏 王斌 王思珩 王毓斌 《上海交通大学学报(医学版)》 CAS CSCD 北大核心 2024年第6期788-794,共7页
受体相互作用蛋白激酶1(receptor-interacting protein kinase 1,RIPK1)是一种多结构域丝氨酸/苏氨酸蛋白激酶。它通过磷酸化特定的蛋白质,引起下游的信号转导和生物效应。近年来,随着对RIPK1的深入研究,学者发现其在自身免疫性疾病、... 受体相互作用蛋白激酶1(receptor-interacting protein kinase 1,RIPK1)是一种多结构域丝氨酸/苏氨酸蛋白激酶。它通过磷酸化特定的蛋白质,引起下游的信号转导和生物效应。近年来,随着对RIPK1的深入研究,学者发现其在自身免疫性疾病、神经退行性疾病,以及多种实体瘤和血液肿瘤中具有重要意义。一方面,RIPK1通过激活特定通路如核因子-κB(nuclear factor-κB,NF-κB)和丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)等促进细胞存活及炎症反应。另一方面,RIPK1通过与胱天蛋白酶-8(cysteinyl aspartate specific proteinase-8,caspase-8)作用促进凋亡,或与RIPK3和混合谱系激酶结构域样假激酶(mixed lineage kinase domain-like protein,MLKL)作用促进坏死性凋亡的发生。RIPK1作为上游信号在不同肿瘤患者中表达水平不同。其支架功能和激酶活性可以调节癌症进展,也可以启动机体适应性免疫,抑制肿瘤进展;此外,还能产生免疫抑制性肿瘤微环境而促进肿瘤的发展。其双重作用在调节癌症的发生、发展及机体免疫反应方面都有所展现,可以作为新的治疗靶点控制癌症进展。该文从RIPK1的结构入手,深入探讨其功能,特别是其在调节癌症进展和免疫反应方面的功能,为癌症靶向药物的开发提供新的思路。 展开更多
关键词 受体相互作用蛋白激酶1 坏死性凋亡 坏死复合物 癌症 免疫反应 靶向治疗
下载PDF
复杂场景下一种改进的单目标跟踪算法研究
18
作者 侯艳丽 魏义仑 +1 位作者 王鑫涛 王娟 《计算机仿真》 2024年第2期300-305,共6页
针对部分复杂场景下目标跟踪存在跟踪框漂移问题,基于孪生候选区域生成网络(SiamRPN),融合通道注意力模块和选择核心模块(SK Module),提出一种单目标跟踪算法CAKSiamRPN。特征提取部分引入高效通道注意模块(ECAM)和基于标准化的通道注... 针对部分复杂场景下目标跟踪存在跟踪框漂移问题,基于孪生候选区域生成网络(SiamRPN),融合通道注意力模块和选择核心模块(SK Module),提出一种单目标跟踪算法CAKSiamRPN。特征提取部分引入高效通道注意模块(ECAM)和基于标准化的通道注意力模块(NCAM),在不降低通道维度的情况下,摒弃相似信息,突出显著特征,关注并提取特定信息;在候选区域生成网络(RPN)嵌入SK Module,增强全局信息嵌入,减少填充操作的影响。将改进算法与SiamRPN及其它经典单目标跟踪算法在OTB100和UAV123数据集上进行实验对比。实验结果表明:跟踪精度和成功率明显提高,能更好地适应复杂场景,具有更强的鲁棒性。 展开更多
关键词 目标跟踪 复杂场景 孪生网络 注意力模块 选择核心模块
下载PDF
加权有向关联网络构建与表征的水中目标远距离检测
19
作者 张红伟 王海燕 +1 位作者 闫永胜 申晓红 《兵工学报》 EI CAS CSCD 北大核心 2024年第8期2584-2593,共10页
水中目标的远距离检测是海洋防御体系的关键技术之一,对国防及民用领域均具有十分重要的作用。然而,目前尚缺乏行之有效的水中目标远距离检测方法,特别是目标先验信息未知的情况下变的愈加困难。为解决这一问题,提出一种新的方法—加权... 水中目标的远距离检测是海洋防御体系的关键技术之一,对国防及民用领域均具有十分重要的作用。然而,目前尚缺乏行之有效的水中目标远距离检测方法,特别是目标先验信息未知的情况下变的愈加困难。为解决这一问题,提出一种新的方法—加权有向关联网络。通过矢量声信号到加权有向关联网络的映射,将信号检测问题转化为网络拓扑的表征,并通过对网络拓扑的特性分析及特征提取,实现无目标先验信息下的水中目标远距离检测。并通过仿真与实测数据对所提出的方法进行验证。研究结果表明:与现有的窄带互谱检测、冒泡熵等方法相比,所提方法能够检测到更低信噪比的水中目标,实现了无需目标先验信息的水中目标远距离检测;该方法的应用具有一定的实际意义和应用前景,可以为海洋防御和民用领域的水下目标检测提供有效的技术支撑。 展开更多
关键词 水中目标 远距离检测 复杂网络 矢量声信号 加权有向关联网络 无目标先验
下载PDF
基于NGG-YOLOv5的空对地UXO目标检测方法
20
作者 刘子玉 赵旭 +1 位作者 李连鹏 代牮 《电光与控制》 CSCD 北大核心 2024年第3期70-74,共5页
为提高无人机在复杂环境下对地面未爆弹(UXO)目标的辨识精度,提出了一种改进YOLOv5的UXO目标检测方法。该方法在YOLOv5的基础上,改进原YOLOv5网络的损失函数以提高对UXO目标的识别精度,同时,通过添加注意力机制、改进马赛克数据增强、... 为提高无人机在复杂环境下对地面未爆弹(UXO)目标的辨识精度,提出了一种改进YOLOv5的UXO目标检测方法。该方法在YOLOv5的基础上,改进原YOLOv5网络的损失函数以提高对UXO目标的识别精度,同时,通过添加注意力机制、改进马赛克数据增强、改进预测框筛选机制提高对UXO目标的识别效率,实现了空对地场景下对UXO目标的检测,并具有较好的精度和速度。实验选取多组不同复杂背景的UXO数据集进行标注并训练,得到UXO目标模型,然后从模型训练结果和目标检测结果的角度评估方法和模型的正确性。实验结果表明:NGG-YOLOv5所得模型检测准确性和检测速度对比原YOLOv5有明显的提升,准确率从78%提高至91%,平均精度均值(mAP)从50%提高至56%,在所用4种复杂背景下均可有效检测出UXO目标,且漏警率低。 展开更多
关键词 空对地探测 YOLOv5 未爆弹目标 深度学习 复杂环境
下载PDF
上一页 1 2 38 下一页 到第
使用帮助 返回顶部