检索结果-南通市图书馆

Robust adaptive radar beamforming based on iterative training sample selection using kurtosis of generalized inner product statistics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2024年第1期35卷 24-30页

作者： tian Jing ZHANG Wei School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Electromagnetic Space Security Chengdu 610036China

In engineering application,there is only one adaptive weights estimated by most of traditional early warning radars for adaptive interference suppression in a pulse reputation interval(PRI).Therefore,if the training samples used to calculate the weight vector does not contain the jamming,then the jamming cannot be removed by adaptive spatial *** the weight vector is constantly updated in the range dimension,the training data may contain target echo signals,resulting in signal cancellation *** cope with the situation that the training samples are contaminated by target signal,an iterative training sample selection method based on non-homogeneous detector(NHD)is proposed in this paper for updating the weight vector in entire range *** principle is presented,and the validity is proven by simulation results.

关键词： adaptive radar beamforming training sample selection non-homogeneous detector electronic jamming jamming suppression

Transformer and GAN-Based Super-Resolution Reconstruction Network for Medical Images

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第1期29卷 197-206页

作者： Weizhi Du Shihao tian Arts&Sciences College Washington University in St.LouisSt.LouisMO 63130USA Department of Electric and Computing Engineering Cornell UniversityIthacaNY 14850USA

Super-resolution reconstruction in medical imaging has become more demanding due to the necessity of obtaining high-quality images with minimal radiation dose,such as in low-field magnetic resonance imaging(MRI).However,image super-resolution reconstruction remains a difficult task because of the complexity and high textual requirements for diagnosis *** this paper,we offer a deep learning based strategy for reconstructing medical images from low resolutions utilizing Transformer and generative adversarial networks(T-GANs).The integrated system can extract more precise texture information and focus more on important locations through global image matching after successfully inserting Transformer into the generative adversarial network for picture ***,we weighted the combination of content loss,adversarial loss,and adversarial feature loss as the final multi-task loss function during the training of our proposed model *** comparison to established measures like peak signal-to-noise ratio(PSNR)and structural similarity index measure(SSIM),our suggested T-GAN achieves optimal performance and recovers more texture features in super-resolution reconstruction of MRI scanned images of the knees and belly.

关键词： super-resolution image reconstruction Transformer generative adversarial network(GAN)

CCL9/CCR1 axis-driven chemotactic nanovesicles for attenuating metastasis of SMAD4-deficient colorectal cancer by trapping TGF-β

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Pharmaceutica Sinica B 2024年第8期14卷 3711-3729页

作者： Boning Niu tianyi tian Lu Wang Yinmei tian tian tian Yuanyuan Guo Hu Zhou Zhiping Zhang Tongji School of Pharmacy Huazhong University of Science and TechnologyWuhan 430030China Department of Oncology Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Department of Pharmacy Liyuan HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China School of Pharmaceutical Sciences Fujian Provincial Key Laboratory of Innovative Drug Target ResearchHigh Throughput Drug Screening PlatformXiamen UniversityXiamen 361102China National Engineering Research Center for Nanomedicine Huazhong University of Science and TechnologyWuhan 430030China Hubei Engineering Research Centre for Novel Drug Delivery System Huazhong University of Science and TechnologyWuhan 430030China

SMAD4 deficiency in colorectal cancer(CRC)is highly correlated with liver metastasis and high mortality,yet there are few effective precision therapies ***,we show that CCR1^(+)-granulocytic myeloid-derived suppressor cells(G-MDSCs)are highly infiltrated in SMAD4-deficient CRC via CCL15/CCR1 and CCL9/CCR1 axis in clinical specimens and mouse models,*** excessive TGF-β,secreted by tumor-infiltrated CCR1^(+)-G-MDSCs,suppresses the immune response of cytotoxic T lymphocytes(CTLs),thus facilitating ***,we develop engineered nanovesicles displaying CCR1 and TGFBR2.molecules(C/T-NVs)to chemotactically target the tumor driven by CCL9/CCR1 axis and trap TGF-βthrough TGF-β-TGFBR2.specific *** C/T-NVs counteract CCR1^(+)-G-MDSC infiltration through competitive responding CCL9/CCR1 axis.C/T-NVs-induced intratumoral TGF-βexhaustion alleviates the TGF-β-suppressed immune response of ***,C/T-NVs attenuate liver metastasis of SMAD4-deficient *** further exploration,high expression of programmed cell death ligand-1(PD-L1)is observed in clinical specimens of SMAD4-deficient *** C/T-NVs with anti-PD-L1 antibody(aPD-L1)induces tertiary lymphoid structure formation with sustained activation of CTLs,CXCL13^(+)-CD4^(+)T,CXCR5^(+)-CD2.^(+)B cells,and enhanced secretion of cytotoxic cytokine interleukin-2. and IFN-γaround tumors,thus eradicating metastatic *** strategy elicits pleiotropic antimetastatic immunity,paving the way for nanovesicle-mediated precision immunotherapy in SMAD4-deficient CRC.

关键词： SMAD4-deficient CRC Metastasis G-MDSCs TGF-β CCR1 TGFBR2

Capturing metal clusters at the strong-interaction region to reverse Ostwald ripening

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Materials 2024年第4期67卷 1363-1364页

作者： Shuheng tian Ding Ma Beijing National Laboratory for Molecular Sciences New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

High-temperature interactions induce sintering of metal nanoparticles(NPs) on heterogeneous catalyst surfaces, leading to reduced surface area and active site loss through Ostwald ripening [1]. This irreversible deactivation necessitates costly catalyst replacement, notably impacting metals like copper in hydrogenation and reforming reactions [2..

关键词： catalyst reforming irreversible

DeepSI:A Sensitive-Driven Testing Samples Generation Method of Whitebox CNN Model for Edge Computing

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第3期29卷 784-794页

作者： Zhichao Lian Fengjun tian School of Cyber Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China

In recent years,Deep Learning(DL)technique has been widely used in Internet of Things(IoT)and Industrial Internet of Things(IIoT)for edge computing,and achieved good *** more and more studies have shown the vulnerability of neural ***,it is important to test the robustness and vulnerability of neural *** specifically,inspired by layer-wise relevance propagation and neural network verification,we propose a novel measurement of sensitive neurons and important neurons,and propose a novel neuron coverage criterion for robustness *** on the novel criterion,we design a novel testing sample generation method,named DeepSI,which involves definitions of sensitive neurons and important ***,we construct sensitive-decision paths of the neural network through selecting sensitive neurons and important ***,we verify our idea by setting up several experiments,then results show our proposed method achieves superior performances.

关键词： neuron sensitivity Layer-wise Relevance Propagation(LRP) neural network verification deeplearning testing

Frequency Domain Fatigue Evaluation on SCR Girth-Weld Based on Structural Stress

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第2期38卷 255-270页

作者： ZHANG Long ZHAO tian-feng College of Safety and Ocean Engineering China University of Petroleum(Beijing)Beijing 102249China

The Steel Catenary Riser(SCR)is a vital component for transporting oil and gas from the seabed to the floating *** harsh environmental conditions and complex platform motion make the SCR’s girth-weld prone to fatigue *** structural stress fatigue theory and Master S-N curve method provide accurate predictions for the fatigue damage on the welded joints,which demonstrate significant potential and compatibility in multi-axial and random fatigue ***,we propose a new frequency fatigue model subjected to welded joints of SCR under multiaxial stress,which fully integrates the mesh-insensitive structural stress and frequency domain random process and transforms the conventional welding fatigue technique of SCR into a spectrum analysis technique utilizing structural ***,a full-scale FE model of SCR with welds is established to obtain the modal structural stress of the girth weld and the frequency response function(FRF)of modal coordinate,and a biaxial fatigue evaluation about the girth weld of the SCR can be achieved by taking the effects of multi-load correlation and pipe-soil interaction into *** research results indicate that the frequency-domain fatigue results are aligned with the time-domain results,meeting the fatigue evaluation requirements of the SCR.

关键词： SCR girth weld random vibration self(cross)power spectrum structural stress method biaxial fatigue damage

小动物实验用镁锰合金颈椎植入物制备及其可行性研究

在线全文

学校读者我要写书评

暂无评论

生物骨科材料与临床研究 2016年第5期13卷 5-8,12,I0003页

作者：耿芳姜明威夏天上海微创骨科医疗科技有限公司上海201203 上海市第一人民医院上海201620

目的应用镁锰合金材料制备用于小动物实验的颈椎植入物,验证表面处理对合金抗腐蚀能力的改进,并分析其用于小动物实验的可行性。方法根据新西兰兔颈椎解剖设计镁锰合金(Mg-1.3Mn)颈椎植入物,应用微弧氧化方法在镁合金表面制备含硅生物... 详细信息

目的应用镁锰合金材料制备用于小动物实验的颈椎植入物,验证表面处理对合金抗腐蚀能力的改进,并分析其用于小动物实验的可行性。方法根据新西兰兔颈椎解剖设计镁锰合金(Mg-1.3Mn)颈椎植入物,应用微弧氧化方法在镁合金表面制备含硅生物活性涂层。体外使用人工组织液浸泡,观察降解情况。体内实验将经表面处理的镁锰合金植入物及同尺寸未经表面处理的镁锰合金植入物、钛合金植入物植入兔颈椎椎体,观察不同时间植入物的体内降解情况。结果镁锰合金颈椎植入物制备成功,表面改性后其抗腐蚀性能明显提高,经手术成功固定于兔颈椎椎体上,与未经表面改性的镁锰合金植入物相比,体内、体外的降解速度均显著降低,扫描电镜及能谱分析等结果表明表面改性的镁锰合金抗腐蚀性有较大改善。结论镁锰合金颈椎植入物可用于小动物颈椎部位实验,适当的表面处理能够有效改进合金的抗腐蚀性能。

关键词：镁锰合金微弧氧化颈椎动物实验

Frost heaving and crack initiation characteristics of tunnel rock mass in cold regions under low-temperature degradation

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第8期21卷 2844-2854页

作者： CHEN Wenhua XIANG tian School of Civil Engineering Beijing Jiaotong UniversityBeijing 202303China

Water freezing in rock fractures causes volumetric expansion and fracture development through frost *** study introduces a novel analytical model to investigate how uneven freezing force and surrounding rock pressure influence fracture initiation,based on mass conservation,elasticity,and water-ice phase transition principles.A model for rock fracture initiation considering freezing temperature,uneven freezing expansion,in-situ stress,and lateral pressure was proposed based on fracture *** for stress intensity factors were developed and validated using the phase field *** effects of rock elastic modulus anisotropy and critical fracture energy density on fracture initiation were also *** results show that the values of KI and KII exhibit an upward trend as the freezing temperature,uneven expansion,in-situ stress,and lateral pressure *** uneven freezing expansion has the most significant influence on KI and KII values among these *** the uneven freezing expansion coefficient increases to 0.5,the fracture initiation mode shifts from tensile fracture to shear *** the lateral pressure coefficient increases to 1,the fracture initiation mode shifts from tensile fracture to shear *** elastic modulus anisotropy causes fractures to propagate in a clockwise direction,forming a'butterfly'*** fracture energy density an isotropy causes counterclockwise deviation in propagation direction,resulting in branching paths and an'H'-shaped pattern.

关键词： Rock fractures Fracture water Uneven freezing expansion Phase field method Initiation angle Anisotropy

Numerical investigation on characteristics of interfacial wave of liquid film in gas-liquid two-phase flow using OpenFOAM

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第2期37卷 233-248页

作者： Xiaoqi MA Yueshe WANG Jiaming tian State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Liquid film cooling as an advanced cooling technology is widely used in space *** operation of liquid film along the rocket combustion inner wall is crucial for thermal protection of rocket *** stability of liquid film is mainly determined by the characteristics of interfacial wave,which is rarely investigated right *** to improve the stability of thin film has become a hot *** view of this,an advanced model based on the conventional Volume of Fluid(VOF)model is adopted to investigate the characteristics of interfacial wave in gas-liquid flow by using OpenFOAM,and the mechanism of formation and development of wave is revealed intuitively through numerical *** effects from gas velocity,surface tension and dynamic viscosity of liquid(three factors)on the wave are studied *** can be found that the gas velocity is critical to the formation and development of wave,and four modes of droplets generation are illustrated in this ***,a gas vortex near the gas-liquid interface can induce formation of wave easily,so changing the gas vortex state can regulate formation and development of ***’s more,the change rules of three factors influencing on the interfacial wave are obtained,and the surface tension has a negative effect on the formation and development of wave only when the surface tension coefficient is above the critical value,whereas the dynamic viscosity has a positive effect in this ***,the maximum height and maximum slope angle of wave will level off as the gas velocity ***,the maximum slope angle of wave is usually no more than 38°,no matter what happens to the three factors.

关键词： Interfacial wave Gas-liquid Two-phase flow VOF model OpenFOAM