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Journal of Materials Science & Technology 2020年第16期47卷 130-136页

作者： Haiwen Luo Xiaohui Wang zhenbao liu Zhiyong Yang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing30 Xue Yuan LuBeijing 100083China Division of Special Steels Central Iron and Steel Research Institute76 Xue Yuan Nan LuBeijing 100081China

The hierarchical martensitic features in ultra-high strength stainless steel(UHSSS),including the prior austenite grains,martensite packets,blocks and laths with the descending size,were refined to various extents by employing different thermomechanical processes and then carefully *** relation to yield strength and impact toughness was *** conclude that the refinement of martensitic structures could lead to the significant increase of yield strength,which follows the Hall-Petch relation with the effect grain size defined by high angle boundaries(HABs).Impact toughness of UHSSS depends on the frequency and capability for retained austenite(RA)grains at both HABs and martensite lath boundaries to trap the propagating cracks via strain-induced transformation,in which the film-like RA grains at lath boundaries appear to make the greater contribution.

关键词： Ultra-high strength stainless steel Martensite Yield strength Impact toughness retained austenite

Robust fixed-time flight controller for a dual-system convertible UAV in the cruise mode

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Defence Technology（防务技术） 2024年第9期39卷 53-66页

作者： Lulu Chen zhenbao liu Qingqing Dang Wen Zhao Wenyu Chen School of Civil Aviation Northwestern Polytechnical UniversityXi'an 710072China Shenzhen Research Institute of Northwestern Polytechnical University Shenzhen 518057China Air and Missile Defense College Air Force Engineering UniversityXi'an 710051China

This paper investigates the attitude tracking control problem for the cruise mode of a dual-system convertible unmanned aerial vehicle(UAV)in the presence of parameter uncertainties,unmodeled uncertainties and wind ***,a fixed-time disturbance observer(FXDO)based on the bi-limit homogeneity theory is designed to estimate the lumped disturbance of the convertible UAV ***,a fixed-time integral sliding mode control(FXISMC)is combined with the FXDO to achieve strong robustness and chattering ***-limit homogeneity theory and Lyapunov theory are applied to provide detailed proof of the fixed-time ***,numerical simulation experimental results verify the robustness of the proposed algorithm to model parameter uncertainties and wind *** addition,the proposed algorithm is deployed in a open-source UAV autopilot and its effectiveness is further demonstrated by hardware-in-the-loop experimental results.

关键词： Convertible UAV Flight control Disturbance observer Fixed-time control

CRISPR/Cas9 systems:Delivery technologies and biomedical applications

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Asian Journal of Pharmaceutical Sciences 2023年第6期18卷 1-31页

作者： Yimin Du Yanfei liu Jiaxin Hu Xingxing Peng zhenbao liu Department of Pharmaceutics Xiangya School of Pharmaceutical SciencesCentral South UniversityChangsha 410013China Department of Pharmaceutical Engineering College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083China Molecular Imaging Research Center of Central South University Changsha 410008China

The emergence of the clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)genome-editing system has brought about a significant revolution in the realm of managing human diseases,establishing animal models,and so *** fully harness the potential of this potent gene-editing tool,ensuring efficient and secure delivery to the target site is ***,developing effective delivery methods for the CRISPR/Cas9 system has become a critical area of *** this review,we present a comprehensive outline of delivery strategies and discuss their biomedical applications in the CRISPR/Cas9 *** also provide an indepth analysis of physical,viral vector,and non-viral vector delivery strategies,including plasmid-,mRNA-and protein-based *** addition,we illustrate the biomedical applications of the CRISPR/Cas9 *** review highlights the key factors affecting the delivery process and the current challenges facing the CRISPR/Cas9 system,while also delineating future directions and prospects that could inspire innovative delivery *** review aims to provide new insights and ideas for advancing CRISPR/Cas9-based delivery strategies and to facilitate breakthroughs in biomedical research and therapeutic applications.

关键词： CRISPR/Cas9 Physical delivery Viral vector Non-viral vector Biomedical applications

Synergistic improvement of strength and ductility via doping cerium into PH13-8Mo stainless steel by laser powder bed fusion

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Journal of Materials Science & Technology 2024年第7期174卷 106-119页

作者： Chang liu Jianxiong Liang Changjun Wang Gang Chen Xuanhui Qu Yu liu zhenbao liu Mengxing Zhang Central Iron&Steel Research Institute Company Limited Beijing 100081China Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China

In this study,the PH13-8Mo stainless steel parts doped without and with cerium(Ce)were fabricated via laser powder bed fusion followed by post-heat treatment,and systematically compared in terms of microstructure,phase constituent,and tensile *** comparative results show that doping Ce-modified grains with the equiaxed morphology and finer size,increased the mechanical stability of austenite,and enhanced the sphericity of oxide inclusion in the resultant ***,the coherency between the newly-formed CeAlO 3 inclusion and matrix was effectively im proved after doping Ce,as compared to the original aluminum oxide inclusion without doping *** resultant PH13-8Mo parts doped with Ce yielded an ultimate tensile strength of 1446±20 MPa with a fracture elongation of 16.0%±1.5%,for the first time meeting the AMS 5629E H1000 standard for the PH13-8Mo made by additive manufacturing(AM).The enhanced strength results from the strengthening effects of nanoscale precipitation(inclusion)and grain ***,the ductilizing mechanism can be attributed to the enhanced inclusion sphericity and ameliorative coherency between the inclusion and matrix,and improved misorientation angle of grain boundary owing to the modification by Ce,which efficiently re-duced the stress concentration and enhanced cracking resistance during ***,doping rare earth elements presents a promising pathway to synergistically improve the strength and ductility of stainless steels by AM.

关键词： Stainless steel Additive manufacturing Rare earth Precipitation Tensile properties

Living cell for drug delivery

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Engineered Regeneration 2022年第2期3卷 131-148页

作者： Yuwei Wu Yanfei liu Ting Wang Qiao Jiang Feng Xu zhenbao liu Department of Pharmaceutics Xiangya School of Pharmaceutical SciencesCentral South UniversityChangsha410013Hunan ProvinceP.R.China Department of Pharmaceutical Engineering College of Chemistry and Chemical EngineeringCentral South UniversityChangsha410083Hunan ProvinceP.R.China Molecular Imaging Research Center of Central South University Changsha 410008HunanP.R.China CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190P.R.China National Clinical Research Center for Metabolic Diseases Hunan Provincial Key Laboratory of Metabolic Bone Diseasesand Department of Endocrinology and MetabolismThe Second Xiang-Ya Hospital of Central South UniversityP.R.China

The living cells have been emerged as useful platforms for drug delivery due to their advantages of good liquidity,stability,and low *** this review,we summarized the development of living cells-based drug delivery *** drug loading methods,applications,and advantages of living cell drug delivery systems were *** living cells for drug delivery,the mechanisms of action,therapeutic applications,as well as main features were summarized and *** recent research progress and challenges were *** future directions and prospects were proposed.

关键词： Drug delivery Living cells Nanomedicine Biomaterials Tumor treatment

Ab Initio Investigations for the Role of Compositional Complexities in Affecting Hydrogen Trapping and Hydrogen Embrittlement:A Review

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Acta Metallurgica Sinica(English Letters) 2023年第7期36卷 1159-1172页

作者： Boning Zhang Yong Mao zhenbao liu Jianxiong Liang Jun Zhang Maoqiu Wang Jie Su Kun Shen Advanced Computing Center School of Materials and EnergyYunnan UniversityKunming650091China Institute for Special Steel Research Central Iron and Steel Research InstituteBeijing100081China Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and EngineeringTsinghua UniversityBeijing100084China School of Science China University of GeosciencesBeijing100083China

ydrogen embrittlement(HE)seriously restricts the service safety of structural metallic materials applicate in aerospace,ocean,and *** studies aiming at increasing the HE-resistance have been focusing on trapping diffusible H atoms by inherent microstructural features in ***-induced compositional complexities,including different types of solute atoms,lattice chemical heterogeneities,and carbide precipitates,have attracted research efforts regarding the H trapping capabilities and potential to reduce the susceptibility to *** this paper,we review recent progress in exploiting compositional complexities to regulate the hydrogen trapping characteristics and mechanical properties in H-containing *** focus is placed on results and insights from ab initio calculations based on density functional theory(DFT).Quantitative predictions of trapping parameters and atomic scale details that are hardly to be gained through traditional experimental characterizations are ***,we overview the electronic/atomistic mechanisms of H trapping energetics in metallic ***,we propose some key challenges and prospects in simulation of defect interactions,interpretation of experimental characterizations,and developing microstructure-based H diffusion prediction *** the applications of first principle calculations,we illustrate how the DFT data can complement experimental characterizations to guide composition and microstructure design for better HE-resistant materials.

关键词： Ab initio calculations Hydrogen trapping Hydrogen embrittlement Precipitation Composition design

Reinforcement learning based UAV formation control in GPS-denied environment

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Chinese Journal of Aeronautics 2023年第11期36卷 281-296页

作者： Bodi MA zhenbao liu Feihong JIANG Wen ZHAO Qingqing DANG Xiao WANG Junhong ZHANG Lina WANG School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710000China Research&Development Institute in Shenzhen Northwestern Polytechnical UniversityShenzhen 518000China Flight Control Division AVIC The First Aircraft InstituteXi’an 710089China

Highly accurate positioning is a crucial prerequisite of multi Unmanned Aerial Vehicle close-formation flight for target tracking,formation keeping,and collision *** the position of a UAV can be obtained through the Global Positioning System(GPS),it is difficult for a UAV to obtain highly accurate positioning data in a GPS-denied environment(e.g.,a GPS jamming area,suburb,urban canyon,or mountain area);this may cause it to miss a tracking target or collide with another *** particular,UAV close-formation control in GPS-denied environments faces difficulties owing to the low-accuracy position,close distance between vehicles,and nonholonomic dynamics of a *** this paper,on the one hand,we develop an innovative UAV formation localization method to address the formation localization issues in GPS-denied environments;on the other hand,we design a novel reinforcement learning based algorithm to achieve the high-efficiency and robust performance of the ***,a novel Lidar-based localization algorithm is developed to measure the localization of each aircraft in the formation *** our solution,each UAV is equipped with Lidar as the position measurement sensor instead of the GPS *** k-means algorithm is implemented to calculate the center point position of UAV.A novel formation position vector matching method is proposed to match center points with UAVs in the formation and estimate their position ***,a reinforcement learning based UAV formation control algorithm is developed by selecting the optimal policy to control UAV swarm to start and keep flying in a close formation of a specific ***,the innovative collision risk evaluation module is proposed to address the collision-free issues in the formation ***,a novel experience replay method is also provided in this paper to enhance the learning *** results validate the accuracy,effectiveness,and robustness of the proposed scheme.

关键词： Close formation control GPS-denied environment Reinforcement learning Unmanned aerial vehicles(UAVs) Intelligent flight control

Let-7i miRNA and platinum loaded nano-graphene oxide platform for detection/reversion of drug resistance and synergetic chemical-photothermal inhibition of cancer cell

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Chinese Chemical Letters 2022年第2期33卷 767-772页

作者： Jianhua Yan Yixuan Zhang Lijuan Zheng Yuwei Wu Ting Wang Ting Jiang Xiaoqin liu Dongming Peng Yanfei liu zhenbao liu Department of Pharmaceutics Xiangya School of Pharmaceutical SciencesCentral South UniversityChangsha 410013China Department of Pharmaceutical Engineering College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083China Department of Medicinal Chemistry School of PharmacyHunan University of Chinese MedicineChangsha 410208China Molecular Imaging Research Center of Central South University Changsha 410008China

The drug resistance of chemotherapy is a major challenge to overcome for antineoplastic agents and the reverse of drug resistant is essential for cancer therapy. Herein, we developed a drug delivery system which can simultaneously detect/reverse the drug resistance and perform synergetic treatment of cancer. In this work, we integrated cyanine5(Cy5) modified mi RNA(let-7 i)(Cy5-mi RNA) and platinum onto nano-graphene oxide(NGO)(30-50 nm) platform to achieve simultaneously detection/reversion of drug resistance and synergetic treatment of cisplatin resistant SKOV3 cells(SKOV3 DDP cells). The Cy5-mi RNA adsorbed on NGO could selectively bind the drug resistance related m RNA follow by suppress the expression of drug resistance m RNA, and the binding simultaneously induced the release of Cy5-mi RNA from the NGO, thus the fluorescence signal of Cy5 recovered and could be used for drug resistance ***, the mi RNA suppressed the Cyclin D1 protein expressions thus reversed the drug resistance. The loaded platinum(Ⅳ)(Pt(Ⅳ)) was converted to the therapeutic platinum(Ⅱ)(Pt(Ⅱ)) in both tumor acidic and reductive environment responsive behavior. NGO furtherly performed photothermal therapy under near infrared(NIR) laser irradiation and enhanced the therapeutic effect. All in all, this nanoplatform realized detection/reversion of the drug resistance as well as synergetic chemical-photothermal treatment of ovarian cancer cells, which holds great promise in the treatment of drug resistant cancer cells.

关键词： Nano-graphene oxide Drug resistance Synergetic chemical-photothermal therapy miRNA Platinum

Tumor microenvironment responsive drug delivery systems

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Asian Journal of Pharmaceutical Sciences 2020年第4期15卷 416-448页

作者： Qunye He Jun Chen Jianhua Yan Shundong Cai Hongjie Xiong Yanfei liu Dongming Peng Miao Mo zhenbao liu Xiangya School of Pharmaceutical Sciences Central South UniversityChangsha 410013China Department of Urology Xiangya HospitalCentral South UniversityChangsha 410008China School of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China School of Pharmacy Hunan University of Chinese MedicineChangsha 410208China

Conventional tumor-targeted drug delivery systems(DDSs)face challenges,such as unsatisfied systemic circulation,low targeting efficiency,poor tumoral penetration,and uncontrolled drug ***,tumor cellular molecules-triggered DDSs have aroused great interests in addressing such *** the introduction of several additional functionalities,the properties of these smart DDSs including size,surface charge and ligand exposure can response to different tumor microenvironments for a more efficient tumor targeting,and eventually achieve desired drug release for an optimized therapeutic *** review highlights the recent research progresses on smart tumor environment responsive drug delivery systems for targeted drug *** targeting strategies and functional moieties sensitive to a variety of tumor cellular stimuli,including pH,glutathione,adenosine-triphosphate,reactive oxygen species,enzyme and inflammatory factors are *** emphasis of this review is placed on their responsive mechanisms,drug loading models,drawbacks and *** typical multi-stimuli responsive DDSs are *** the main challenges and potential future development are discussed.

关键词： Cancer therapy Stimuli responsive Dynamic targeting Drug delivery system Controlled release

基于多层多向Transformer的红外弱小目标检测

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航空学报 2024年第14期45卷 1-13页

作者：王潇刘贞报西北工业大学民航学院西安710072

针对基于卷积神经网络的红外图像弱小目标检测方法面临卷积神经网络的感受野有限,扩展感受野的下采样操作容易导致特征丢失,以及卷积网络对局部对比特征提取能力有限的问题,提出了一种基于多层多向Transformer的红外图像弱小目标检测算... 详细信息

针对基于卷积神经网络的红外图像弱小目标检测方法面临卷积神经网络的感受野有限,扩展感受野的下采样操作容易导致特征丢失,以及卷积网络对局部对比特征提取能力有限的问题,提出了一种基于多层多向Transformer的红外图像弱小目标检测算法。首先使用感受野较大、对比特征提取能力较强的Transformer网络作为基本单元,设计U型深度神经网络和多特征层融合网络将局部特征以及全局特征进行融合。同时在解码网络设计双向注意力算子,利用自注意力计算机制分别计算空间方向和特征方向的注意力特征,进一步提高深度网络提取弱小目标和周边区域对比特征的能力。另外在主干网络最后添加数量约束网络,通过统计对比检测结果中目标的数量,减小误检目标的数目,提高目标检测的准确度。最后在多个实验数据集上和已有方法进行了对比实验,在各个评价参数上取得了最多35%的提升,证明所提红外弱小目标检测算法具有较高的准确性。

关键词：红外弱小目标检测 Transformer 多特征层融合双向注意力算子数量约束