检索结果-南通市图书馆

Investigation of high rate mechanical flow followed by ignition for high-energy propellant under dynamic extrusion loading

引用

Defence Technology（防务技术） 2024年第2期32卷 336-347页

作者： Liying dong Yanqing Wu kun yang Xiao Hou State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China

Investigating the ignition response of nitrate ester plasticized polyether(NEPE) propellant under dynamic extrusion loading is of great significant at least for two cases. Firstly, it helps to understand the mechanism and conditions of unwanted ignition inside charged propellant under accident ***, evaluates the risk of a shell crevice in a solid rocket motor(SRM) under a falling or overturning scene. In the present study, an innovative visual crevice extrusion experiment is designed using a dropweight apparatus. The dynamic responses of NEPE propellant during extrusion loading, including compaction and compression, rapid shear flow into the crevice, stress concentration, and ignition reaction, have been firstly observed using a high-performance high-speed camera. The ignition reaction is observed in the triangular region of the NEPE propellant sample above the crevice when the drop weight velocity was 1.90 m/s. Based on the user material subroutine interface UMAT provided by finite element software LS-DYNA, a viscoelastic-plastic model and dual ignition criterion related to plastic shear dissipation are developed and applied to the local ignition response analysis under crevice extrusion conditions. The stress concentration occurs in the crevice location of the propellant sample, the shear stress is relatively large, the effective plastic work is relatively large, and the ignition reaction is easy to occur. When the sample thickness decreases from 5 mm to 2.5 mm, the shear stress increases from 22.3 MPa to 28.6 MPa, the critical value of effective plastic work required for ignition is shortened from 1280 μs to 730 μs, and the triangular area is easily triggering an ignition reaction. The propellant sample with a small thickness is more likely to stress concentration, resulting in large shear stress and effective work, triggering an ignition reaction.

关键词： NEPE propellant Crevice extrusion Shear flow Sample thickness Ignition reaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Controlled Twill Surface Structure Endowing Nanofiber Composite Membrane Excellent Electromagnetic Interference Shielding

引用

Nano-Micro Letters 2024年第11期16卷 255-273页

作者： Dechang Tao Xin Wen Chenguang yang kun Yan Zhiyao Li Wenwen Wang dong Wang Key Laboratory of Textile Fiber and Products(Wuhan Textile University) Ministry of EducationWuhan Textile UniversityWuhan 430200People’s Republic of China College of Chemistry Chemical Engineering and BiotechnologyDonghua UniversityShanghai 201620People’s Republic of China

Inspired by the Chinese Knotting weave structure,an electromagnetic interference(EMI)nanofiber composite membrane with a twill surface was ***(vinyl alcohol-co-ethylene)(Pva-co-PE)nanofibers and twill nylon fabric were used as the matrix and filter templates,respectively.A Pva-co-PEMXene/silver nanowire(Pva-co-PE-MXene/AgNW,PM_(x)Ag)membrane was successfully prepared using a template *** the MXene/AgNW content was only 7.4 wt%(PM_(7.4)Ag),the EMI shielding efficiency(SE)of the composite membrane with the oblique twill structure on the surface was 103.9 dB and the surface twill structure improved the EMI by 38.5%.This result was attributed to the pre-interference of the oblique twill structure in the direction of the incident EM wave,which enhanced the probability of the electromagnetic waves randomly colliding with the MXene ***,the internal reflection and ohmic and resonance losses were *** PM_(7.4)Ag membrane with the twill structure exhibited both an outstanding tensile strength of 22.8 MPa and EMI SE/t of 3925.2 dB cm^(-1).Moreover,the PM_(x)Ag nanocomposite membranes demonstrated an excellent thermal management performance,hydrophobicity,non-flammability,and performance stability,which was demonstrated by an EMI SE of 97.3%in a high-temperature environment of 140℃.The successful preparation of surface-twill composite membranes makes it difficult to achieve both a low filler content and a high EMI SE in electromagnetic shielding *** strategy provides a new approach for preparing thin membranes with excellent EMI properties.

关键词： Twill surface structure MXene/AgNW Nanofiber membrane Electromagnetic interference Flexibility and mechanical properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A scalable versatile methodology to construct micro/nano open-cell polypropylene foam with high oil adsorption capacity and speed

引用

Nano Research 2024年第4期17卷 2814-2823页

作者： Chenguang yang Dechang Tao kun Yan Zhiyao Li Qingshi Guo Wenwen Wang dong Wang Key Laboratory of Textile Fiber and Products(Wuhan Textile University) Ministry of EducationWuhan Textile UniversityWuhan 430200China College of Chemistry Chemical Engineering and BiotechnologyDonghua UniversityShanghai 201620China

Oil pollution is a serious environmental and natural resource *** adsorption materials for oil–water separation have limitations in terms of their preparation cost,reusability,and mechanical *** the conventional adsorption materials,super-hydrophobic/super-lipophilic materials are easily contaminated by *** this study,polypropylene(PP)is used as a foam substrate to prepare an open-cell PP foam via hot pressing,supercritical CO_(2) foaming,and electron beam(EB)*** impact of EB irradiation dose on the open-cell content of PP foam can lead to cell wall rupture,resulting in an open-cell structure that enhances oil-water separation *** an absorbed radiation dose of 200 kGy,the PP foams exhibit optimal oil–water separation performance,cyclic compression stability,heat insulation,and preparation *** open-cell content of PP foam is increased to 86.5%,the adsorption capacity for diesel oil is 42.8 g/g,and the adsorption efficiency remains at 99.6%after 100 cycles of oil desorption in a complex pH ***,cracks and nano-voids simultaneously promote the capillary action of oil,and the oil transport rate is 0.0713 g/(g·s).This study provides a new concept for the preparation of open-cell polymer foams that can meet the demand for high oil-absorption capacity under complex acid-base pH conditions.

关键词： open-cell polypropylene(PP)foam electron beam irradiation oil/water separation cyclic compression complex acid-base pH conditions

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Fair and Trusted Trading Scheme for Medical Data Based on Smart Contracts

引用

Computers, Materials & Continua 2024年第2期78卷 1843-1859页

作者： Xiaohui yang kun Zhang School of Cyber Security and Computer Hebei UniversityBaoding071000China

Data is regarded as a valuable asset,and sharing data is a prerequisite for fully exploiting the value of ***,the current medical data sharing scheme lacks a fair incentive mechanism,and the authenticity of data cannot be guaranteed,resulting in low enthusiasm of participants.A fair and trusted medical data trading scheme based on smart contracts is proposed,which aims to encourage participants to be honest and improve their enthusiasm for *** scheme uses zero-knowledge range proof for trusted verification,verifies the authenticity of the patient’s data and the specific attributes of the data before the transaction,and realizes privacy *** the same time,the game pricing strategy selects the best revenue strategy for all parties involved and realizes the fairness and incentive of the transaction *** smart contract is used to complete the verification and game bargaining process,and the blockchain is used as a distributed ledger to record the medical data transaction process to prevent data tampering and transaction ***,by deploying smart contracts on the Ethereum test network and conducting experiments and theoretical calculations,it is proved that the transaction scheme achieves trusted verification and fair bargaining while ensuring privacy protection in a decentralized *** experimental results show that the model improves the credibility and fairness of medical data transactions,maximizes social benefits,encourages more patients and medical institutions to participate in the circulation of medical data,and more fully taps the potential value of medical data.

关键词： Blockchain data transactions zero-knowledge proof game pricing

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Picotesla fiberized diamond-based AC magnetometer

引用

Photonics Research 2024年第6期12卷 1250-1261页

作者： SHAO-CHUN ZHANG YONG LIU LONG-kun SHAN XUE-dong GAO JIA-QI GENG CUI YU yang dong XIANG-dong CHEN GUANG-CAN GUO FANG-WEN SUN CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China National Key Laboratory of ASIC Hebei Semiconductor Research InstituteShijiazhuang 050051China Electric Power Quantum Sensing Joint Laboratory of Anhui Province State Grid Anhui Electric Power Research InstituteHefei 230601China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Portable quantum sensors are crucial for developing practical quantum sensing and metrology *** nitrogen-vacancy(NV)centers in diamonds have emerged as one of the most promising candidates for compact quantum ***,due to the difficulty of coherently controlling the ensemble spin and noise suppression in a large volume,it often faces problems such as reduced sensitivity and narrowed bandwidth in integrated lensless ***,we propose a fluorescence signal treatment method for NV spin ensemble manipulation by the exponential fitting of spin polarization processes,instead of integrating the photon *** enables spin state readout with a high signal-to-noise ratio and applies to the pulse sensing protocols for large-volume NV *** on this,we further developed a fiberized diamond-based AC *** an XY8-N dynamical decoupling pulse sequence,we demonstrated a T_(2)-limited sensitivity of 8pT/√Hz and T_(1)-limited frequency resolution of 90 Hz over a wide frequency band from 100 kHz to 3 *** integrated diamond sensor leverages quantum coherence to achieve enhanced sensitivity in detecting AC magnetic fields,making it suitable for implementation in a compact and portable endoscopic sensor.

关键词： magnetometer quantum ensemble

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Interaction of human fibrinogen receptor (GPIIb-Ⅲa) with decorsin

引用

Acta Pharmacologica Sinica 2004年第8期 122-130页

作者： Jie yang, Chen-yang ZHAN, Xian-chi dong, kun yang, Fu-xiang WANG State Key Laboratory of Pharmaceutical Biotechnology, Life Science College, Nanjing University, Nanjing 210093, China

AIM: To build up the structure of human fibrinogen receptor GPⅡb-Ⅲa, subsequently combined with its antagonist decorsin, and to investigate the interaction between decorsin and its receptor GPⅡb-Ⅲa at the molecular level. METHODS: A three-dimensional (3D) molecular model of human fibrinogen receptor GPⅡb-Ⅲa was generated by InsightⅡ, a distance geometry-based homologous modeling package. The structure of human fibrinogen receptor GPⅡb-Ⅲa was built by the InsightⅡ/Homology module using the corresponding of integrin alpha Vbeta.3 (PDB filecode 1JV2) as the template. Then the primary structures were optimized by energy minimization. Subsequently the structural model was docked with its antagonist decorsin (PDB filecode 1dec). RESULTS: A good substrate receptor interaction model was achieved. The interaction sites with decorsin converge at domain 8 (βA domain of β3 subunit) of GPⅡb-Ⅲa. The direct interatomic contacts were made between 16 GPⅡb/Ⅲa residues and 10 decorsin amino-acid residues. T

关键词： platelet glycoprotein GPIIb-Ⅲa complex decorsin drug design

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Low-resolution Kramers-Kronig detection system with error-feedback noise shaping

引用

Science China(Information Sciences) 2024年第5期67卷 259-269页

作者： Xiangyong dong Zhenming YU Hongyu HUANG Kaixuan SUN kun XU State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

In this paper, we investigated the effects of error-feedback noise shaping(EFNS) on a lowresolution Kramers-Kronig(KK) detection system for the first time. Both 16-ary quadrature amplitude modulation(16-QAM) and 64-ary quadrature amplitude modulation(64-QAM) were considered in the experiment. The carrier tone was added on the transmitter side using the virtual carrier-assisted single sideband(VCA-SSB) method to meet the minimum phase(MP) condition. Under the MP condition, KK detection only needs the intensity of the optical signal to be detected by one photodiode(PD) to retrieve the phase information. However, the virtual carrier tone increases the carrier-to-signal power ratio(CSPR), which results in a high peak-to-average power ratio(PAPR) at the transmitter, causing an increase in quantization noise. To mitigate quantization noise in the low-resolution KK detection system, EFNS was applied. The application of EFNS increased the optimal CSPR of the KK detection system and improved receiver sensitivity. Using a 4-bit DAC and the EFNS, 80 km transmission was achieved in the 60-Gbit/s 64-QAM KK detection system.

关键词： optical fiber communications Kramers-Kronig receiver error-feedback noise shaping quantization noise carrier-to-signal power ratio

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Discovering Latent Variables for the Tasks With Confounders in Multi-Agent Reinforcement Learning

引用

IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1591-1604页

作者： kun Jiang Wenzhang Liu Yuanda Wang Lu dong Changyin Sun the School of Automation Southeast UniversityNanjing 210096China the School of Artificial Intelligence Anhui UniversityHefei 230601China IEEE the School of Cyber Science and Engineering Southeast UniversityNanjing 211189China the Engineering Research Center of Autonomous Unmanned System Technology Ministry of EducationHefei 230601China

Efficient exploration in complex coordination tasks has been considered a challenging problem in multi-agent reinforcement learning(MARL). It is significantly more difficult for those tasks with latent variables that agents cannot directly observe. However, most of the existing latent variable discovery methods lack a clear representation of latent variables and an effective evaluation of the influence of latent variables on the agent. In this paper, we propose a new MARL algorithm based on the soft actor-critic method for complex continuous control tasks with confounders. It is called the multi-agent soft actor-critic with latent variable(MASAC-LV) algorithm, which uses variational inference theory to infer the compact latent variables representation space from a large amount of offline ***, we derive the counterfactual policy whose input has no latent variables and quantify the difference between the actual policy and the counterfactual policy via a distance function. This quantified difference is considered an intrinsic motivation that gives additional rewards based on how much the latent variable affects each agent. The proposed algorithm is evaluated on two collaboration tasks with confounders, and the experimental results demonstrate the effectiveness of MASAC-LV compared to other baseline algorithms.

关键词： Latent variable model maximum entropy multi-agent reinforcement learning(MARL) multi-agent system

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Resonance mechanism of flapping wing based on fluid structure interaction simulation

引用

Chinese Journal of Aeronautics 2024年第5期37卷 243-262页

作者： Yueyang GUO Wenqing yang Yuanbo dong dong XUE National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang 215400China

Certain insect species have been observed to exploit the resonance mechanism of their *** order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)***,there exists controversy among researchers regarding the relationship between frequency and aerodynamic *** that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant *** this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM *** performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic ***,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum ***,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible ***,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure *** paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.

关键词： Flexible Flapping Wing(FFW) Acoustic Structure Interaction Modal(ASIM) Fluid Structure Interaction(FSI) Resonance mechanism Aerodynamic performance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Using MsfNet to Predict the ISUP Grade of Renal Clear Cell Carcinoma in Digital Pathology Images

引用

Computers, Materials & Continua 2024年第1期78卷 393-410页

作者： kun yang Shilong Chang Yucheng Wang Minghui Wang Jiahui yang Shuang Liu kun Liu Linyan Xue College of Quality and Technical Supervision Hebei UniversityBaoding071002China National and Local Joint Engineering Research Center of Metrology Instrument and System Hebei UniversityBaoding071002China Hebei Technology Innovation Center for Lightweight of New Energy Vehicle Power System Hebei UniversityBaoding071002China

Clear cell renal cell carcinoma(ccRCC)represents the most frequent form of renal cell carcinoma(RCC),and accurate International Society of Urological Pathology(ISUP)grading is crucial for prognosis and treatment *** study presents a new deep network called Multi-scale Fusion Network(MsfNet),which aims to enhance the automatic ISUP grade of ccRCC with digital histopathology pathology *** MsfNet overcomes the limitations of traditional ResNet50 by multi-scale information fusion and dynamic allocation of channel *** model was trained and tested using 90 Hematoxylin and Eosin(H&E)stained whole slide images(WSIs),which were all cropped into 320×320-pixel patches at 40×*** achieved a micro-averaged area under the curve(AUC)of 0.9807,a macro-averaged AUC of 0.9778 on the test *** Gradient-weighted Class Activation Mapping(Grad-CAM)visually demonstrated MsfNet’s ability to distinguish and highlight abnormal areas more effectively than *** t-Distributed Stochastic Neighbor Embedding(t-SNE)plot indicates our model can efficiently extract critical features from images,reducing the impact of noise and redundant *** results suggest that MsfNet offers an accurate ISUP grade of ccRCC in digital images,emphasizing the potential of AI-assisted histopathological systems in clinical practice.

关键词： Renal cell carcinoma computer-aided diagnosis pathology image deep learning machine learning

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：