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Theoretical Analysis and Numerical Simulation of the Motion of RDX Deflagration-Driven Flyer Plate Based on Laser-Initiated Micro-Pyrotechnic Devices

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MICROMACHINES 2023年第5期14卷 917-917页

作者： Xian, Mingchun Zhao, Kang liu, xuwen Meng, Yangang Xie, Junyao li, Jingwei Tong, Lele Huang, Meng Wu, lizhi Nanjing Univ Sci & Technol Sch Chem & Chem Engn Nanjing 210094 Peoples R China Sichuan Aerosp Chuannan Pyrotech Co Ltd Luzhou 646000 Peoples R China Jianghan Univ State Key Lab Precis Blasting Wuhan 430056 Peoples R China

Miniaturized laser-initiated pyrotechnic devices have great application prospects in aerospace and modern weapon systems due to their excellent energy output performance and reliability. In order to develop a low-energy insensitive laser detonation technology based on a two-stage charge structure, it is important to deeply analyze the motion law of a titanium flyer plate driven by the deflagration of the first-stage charge (RDX). The effects of the charge mass of RDX, flyer plate mass, and barrel length on the motion law of flyer plates were studied through a numerical simulation method based on the Powder Burn deflagration model. The consistency between the numerical simulation and the experimental results was analyzed using the paired t confidence interval estimation method. The results show that the Powder Burn deflagration model can effectively describe the motion process of the RDX deflagration-driven flyer plate with a 90% confidence level, and its velocity error is =6.7%. The speed of the flyer plate is proportional to the mass of the RDX charge, inversely proportional to the mass of the flyer plate, and exponentially related to its moving distance. As the moving distance of the flyer plate increases, the RDX deflagration products and air in front of the flyer plate are compressed, which inhibits the motion of the flyer plate. In the optimum state (the mass of the RDX charge is 60 mg, the mass of the flyer is 85 mg, and the length of the barrel is 3 mm), the speed of the titanium flyer reaches 583 m/s, and the peak pressure of the RDX deflagration reaches 2182 MPa. This work will provide a theoretical basis for the refined design of a new generation of miniaturized high-performance laser-initiated pyrotechnic devices.

关键词： laser-initiated deflagration-driven flyer plate powder burn

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60岁以下人群急性主动脉夹层CT平扫影像征象的初步研究

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中国继续医学教育 2018年第27期10卷 51-53页

作者：李颖李旭文内蒙古民族大学第二临床医学院/内蒙古林业总医院医学影像科内蒙古牙克石022150 上海市松江区泗泾医院放射科上海201600

目的总结60岁以下人群(不包括60岁,下文以<60岁表示)急性主动脉夹层多排螺旋CT平扫诊断征象,提高<60岁人群主动脉夹层CT平扫诊断准确率。方法回顾分析本院2013年1月—2017年12月主要因突发急性胸痛、腹痛等病因急诊就诊的患者44例... 详细信息

目的总结60岁以下人群(不包括60岁,下文以<60岁表示)急性主动脉夹层多排螺旋CT平扫诊断征象,提高<60岁人群主动脉夹层CT平扫诊断准确率。方法回顾分析本院2013年1月—2017年12月主要因突发急性胸痛、腹痛等病因急诊就诊的患者44例。<60岁年龄组14例,年龄最小45岁,最大54岁,平均(49.8±3.2)岁。≥60岁年龄组30例,年龄最小61岁,最大81岁,平均(71.2±6.3)岁。均行64排螺旋CT胸部扫描或胸腹部联扫,平扫检查后当日至一周内在本院行CTA检查明确诊断为主动脉夹层。对44例确诊主动脉夹层患者平扫诊断征象进行数据总结,结果使用SPSS软件进行χ~2检验。结果 (1)主动脉增粗,(2)钙斑内移,(3)主动脉内密度不均,(4)主动脉腔见内膜片影,(5)心包积液,(6)胸膜增厚,(7)胸腔积液,(8)背侧肺野高密度影,以上诊断征象经统计学分析,(2)～(8)的诊断征象在≥60岁年龄组与<60岁年龄组间差异具有统计学意义,P<0.05。征象(2)(3)(7)在≥60岁年龄组发生率较高;征象(4)(5)(6)(8)在<60岁年龄组发生率较高。结论 <60岁年龄组主动脉夹层主要表现为主动脉腔内见内膜片影、心包积液、胸膜增厚、背侧肺野高密度影四个征象,以上四个征象对<60岁人群主动脉夹层平扫诊断更具有特征性。

关键词：急性主动脉夹层 <60岁内膜片影心包积液胸膜增厚背侧肺野高密度影

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Theoretical and experimental study on vibration sensitivity of cubic cavity for space applications

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OPTICS AND LASER TECHNOLOGY 2023年第PartA期158卷

作者： Chen, Long Hu, xuwen Han, liang Xu, Guanjun liu, Lei li, Yang liu, Tao Dong, Ruifang Zhang, Shougang Chinese Acad Sci Natl Time Serv Ctr Xian 710600 Peoples R China Northwestern Polytech Univ Sch Astronaut Xian 710072 Peoples R China Chinese Acad Sci Key Lab Time & Frequency Stand Xian 710600 Peoples R China

The increasing performance of ultra-stable lasers has made them attractive for non-laboratory and space field applications. How to reduce the vibration sensitivity of the optical reference cavity is one of the key points. To develop vibration-insensitive cavity for space applications, we investigate the vibration sensitivity of a cubic cavity with the length of 100 mm theoretically and experimentally. The functional expression of the fractional length change of the cubic cavity versus the cutting depth of the cubic spacer vertices and the compressive forces is presented for the first time. The vibration sensitivity of the 100 mm cubic cavity is measured as low as 2 x 10-11/g. Based on the vibration-insensitive cubic cavity, a 1 Hz-linewidth laser system with an envelope size of 450 mm x 541 mm x 598 mm is developed, which would be the prototype for space applications.

关键词： Vibration sensitivity Cubic cavity Ultra-stable laser

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VDE-SAT下行链路信道建模方法

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中国科学院大学学报（中英文） 2024年第2期41卷 249-256页

作者：丁港辉李宗旺谢卓辰梁旭文中国科学院微小卫星创新研究院中国科学院微小卫星重点实验室上海201203 中国科学院大学北京100049

海面的散射特性导致VDES海上通信信道模型复杂多变,在VDE-SAT下行链路中,低仰角通信导致海浪反射带来的多径效应更加严重。针对此问题,提出一种基于球坐标系的VDE-SAT下行链路信道建模方法,根据不同海情级分析海浪反射对于信号接收特性... 详细信息

海面的散射特性导致VDES海上通信信道模型复杂多变,在VDE-SAT下行链路中,低仰角通信导致海浪反射带来的多径效应更加严重。针对此问题,提出一种基于球坐标系的VDE-SAT下行链路信道建模方法,根据不同海情级分析海浪反射对于信号接收特性的影响。首先,将海面散射特性的统计结果参数化,结合地球曲率的影响,建立基于球坐标系的星船通信几何模型,基于此,得到海面有效漫反射区。其次,建立星船通信链路的信号多径传播模型,基于G1139协议,根据各个路径的信道参数分析接收信号的功率分布,以及不同海情级下信号的接收特性。仿真结果表明:在海况较好时,该多径信道以镜面反射为主;海况较差时,以漫反射为主。相比于卷积码,Turbo码的抗多径性能更优。

关键词： VDE-SAT 信道模型卫星通信多径效应

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Multi-scale Feature Fusion Extraction Structure for the Leather Defect Detection Algorithm

Multi-scale Feature Fusion Extraction Structure for the Leat...

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Pattern Recognition and Artificial Intelligence (PRAI), International Conference on

作者： xuwen He Hao li Zihan Huang Xiaorui Xiong Yifan liu Yuting Yao School of Mathematics and Computer Science Wuhan Polytechnic University Wuhan China

Detection of surface defects using computer vision is a pivotal technology for achieving intelligent manufacturing. Leather products are one of the most widely traded goods in the world, and automatic identification, localization, and detection of surface defects in leather are indispensable for achieving intelligent manufacturing of leather products. This research paper proposes FG-DETR, a multi-scale feature fusion extraction structure for small target detection algorithms. Given the recent success of deep learning methods in various related fields and that certain defects and flaws in leather pictures in our dataset are relatively small. FG-DETR is based on DETR with some improvements as follows, Initially, DETR's ResNet50 network performs feature extraction on the original image and produces four scales of feature maps. Second, we apply a modified Feature Pyramid Network (FPN) to downsample and upsample the four scales of feature maps, followed by the fusion and output of a single feature map. A Gaussian kernel and output then process the fused feature maps as the final feature maps. Finally, the feature maps are merged with the position encoding information and combined into the Transformer encoder-decoder architecture, resulting in the detection outcomes through the Position-wise Feed-Forward Networks (FFN). In our leather dataset, the FG-DETR model is more effective in detecting small targets than DETR, as our leather images are large, and the original DETR is nearly ineffective for images with relatively small defects. The average detection accuracy of medium and large targets also improved, with a 7.6 percentage point improvement at AP50. The experimental findings demonstrate that the multi-scale feature fusion extraction structure significantly enhances the detection accuracy of DETR.

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Effects of Micellization Behavior on the Interfacial Adsorption in Binary Anionic/Nonionic Surfactant Systems: A Molecular Simulation Study

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LANGMUIR 2021年第40期37卷 11835-11843页

作者： lian, Peng Jia, Han Yan, Hui Yuan, Jie Tang, Hongtao li, Zhe Fan, Fangning Qin, xuwen Lv, Kaihe liu, Dexin China Univ Petr East China Sch Petr Engn Qingdao 266580 Peoples R China China Univ Petr East China Sch Petr Engn Shandong Key Lab Oilfield Chem Qingdao 266580 Peoples R China Liaocheng Univ Sch Pharmaceut Sci Liaocheng 252059 Shandong Peoples R China SINOPEC Shengli Oilfield Co Shengli Oil Prod Plant Dongying 257000 Peoples R China

A surfactant interfacial adsorption process is highly associated with its micellization behaviors in the water phase, which is of great fundamental and practical significance in enhanced oil recovery. In this paper, the typical anionic surfactant 1-dodecanesulfonic acid sodium (DAS) and nonionic surfactants octylphenol polyoxyethylene ether-n (OP-n, n = 1, 5, and 10) are introduced to investigate their micellization behavior and interfacial adsorption process via molecular dynamics simulation. Number density profiles reveal that the additional OP5 molecules in the water phase generate the mixed micelle with DAS molecules and greatly promote its interfacial adsorption. Interaction energy calculation is employed to confirm the interaction of anionic/nonionic surfactants in the mixed micelle. Then, the radial distribution function, solvent-accessible surface area, and solvation free energy are calculated to further explore and verify the adsorption mechanism of the mixed micelle. It is found that the nonionic surfactant obviously decreases the hydrophilicity of the mixed micelle in the water phase, which should be responsible for its intensive tendency of the interfacial adsorption.

关键词： Adsorption Molecules Micelles Surfactants Water

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Efficient Removal of Organic Matter from Biotreated Coking Wastewater by Coagulation Combined with Sludge-Based Activated Carbon Adsorption

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WATER 2022年第15期14卷 2446-2446页

作者： Xia, Yu li, Weijia He, xuwen liu, Dannuo Sun, Yichen Chang, Jie liu, Jing China Univ Min & Technol Beijing Sch Chem & Environm Engn Beijing 100083 Peoples R China

Coagulation-adsorption can be effective in the removal of the organic matters remaining in biotreated coking wastewater (BTCW), and cheap and efficient adsorbents benefit the widespread application of this technology. In this study, a sludge-based activated carbon (SAC) was prepared using zinc chloride to activate sludge pyrolysis carbon for the treatment of BTCW with coagulation as the pretreatment process. According to Brunauer-Emmett-Teller (BET) and the scanning electron microscope (SEM) analysis, the SAC exhibited a specific surface area of 710.175 m(2)/g and well-developed pore structure. The removal characteristics of the organic matter in BTCW were systematically studied. The results show that 76.79% of the COD in the BTCW was removed by coagulation combined with SAC adsorption, and the effluent COD was below the discharge limit (80 mg/L) (GB16171-2012), with the optimal dosages of polyaluminum chloride and SAC being 150 mg/L and 4 g/L, respectively. Compared with a commercial powdered activated carbon (PAC) (48.26%), the SAC achieved a similar COD removal efficiency (47.74%) at a higher adsorption speed. The removal efficiencies of the hydrophobic components (77.27%) and fluorescent components by SAC adsorption were higher than those by PAC adsorption. The SAC also had an excellent removal effect on complex organic compounds and colored substances in the BTCW, as revealed by UV-vis spectra analyses.

关键词： sludge-based activated carbon biotreated coking wastewater coagulation adsorption organic pollutants

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SERIES OF DIMERIC INDOLE ALKALOID COMPOUNDS, PREPARATION METHOD THEREFOR AND USE OF SAME IN PREPARATION OF ANTIBACTERIAL DRUGS

SERIES OF DIMERIC INDOLE ALKALOID COMPOUNDS, PREPARATION MET...

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作者： GUO, Yuewei LAN, Lefu li, xuwen CHEN, Feifei liU, Jin

标准号: WO2019072112(A1)

The present invention falls within in the fields of organic synthesis and pharmaceutical chemistry. In particular, the present invention relates to a series of dimeric indole alkaloid compounds as shown in structural general formula I, preparation methods therefor and the use of same in the preparation of antibacterial drugs. After same undergo in vitro activity screening, the results show that such compounds have strong antibacterial activity, in particular have specific inhibitory effects on gram-positive bacteria, such as strains of staphylococcus, bacillus and enterococcus, and related drug-resistant strains thereof, and can be used as the lead compounds for developing new antibacterial drugs.

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A novel injectable calcium phosphate-based nanocomposite for the augmentation of cannulated pedicle-screw fixation

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INTERNATIONAL JOURNAL OF NANOMEDICINE 2017年第20170427期12卷 3395-3406页

作者： Sun, Haolin liu, Chun liu, Huiling Bai, Yanjie Zhang, Zheng li, xuwen li, Chunde Yang, Huilin Yang, Lei Peking Univ Dept Orthoped Hosp 1 8 Xishiku St Beijing 100034 Peoples R China Soochow Univ Inst Orthoped Dept Orthoped Affiliated Hosp 1 Suzhou Peoples R China Soochow Univ Sch Publ Hlth Med Coll Suzhou Peoples R China Soochow Univ IRCTO Suzhou Peoples R China

Polymethyl methacrylate (PMMA)-augmented cannulated pedicle-screw fixation has been routinely performed for the surgical treatment of lumbar degenerative diseases. Despite its satisfactory clinical outcomes and prevalence, problems and complications associated with high-strength, stiff, and nondegradable PMMA have largely hindered the long-term efficacy and safety of pedicle-screw fixation in osteoporotic patients. To meet the unmet need for better bone cement for cannulated pedicle-screw fixation, a new injectable and biodegradable nanocomposite that was the first of its kind was designed and developed in the present study. The calcium phosphate-based nanocomposite (CPN) exhibited better anti-pullout ability and similar fluidity and dispersing ability compared to clinically used PMMA, and outperformed conventional calcium phosphate cement (CPC) in all types of mechanical properties, injectability, and biodegradability. In term of axial pullout strength, the CPN-augmented cannulated screw reached the highest force of similar to 120 N, which was higher than that of PMMA (similar to 100 N) and CPC (similar to 95 N). The compressive strength of the CPN (50 MPa) was three times that of CPC, and the injectability of the CPN reached 95%. In vivo tests on rat femur revealed explicit biodegradation of the CPN and subsequent bone ingrowth after 8 weeks. The promising results for the CPN clearly suggest its potential for replacing PMMA in the application of cannulated pedicle-screw fixation and its worth of further study and development for clinical uses.

关键词： calcium phosphate nanocomposite injectable biodegradable pedicle screw lumbar degenerative disease osteoporosis

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Genome-wide association screening and verification of potential genes associated with defoliation rate induced by defoliant in upland cotton

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INDUSTRIAL CROPS AND PRODUCTS 2024年 217卷

作者： Pan, Zhenyuan Zhou, Xiaofeng Wang, Runze li, Juan Ding, Shugen Han, Peng Wang, xuwen Zhao, Zhansheng Wu, Yuanlong Nie, Xinhui Yu, Yu Xinjiang Acad Agr & Reclamat Sci Shihezi 832000 Peoples R China Shihezi Univ Key Lab Oasis Ecol Agr Xinjiang Prod & Construct C Agr Coll Shihezi 832003 Peoples R China Agr Sci Res Inst Div Xinjiang Prod Construct Corps 6 Wujiaqu 835099 Peoples R China

Defoliant sensitivity is an important trait of machine-picked cotton that directly affects the defoliation efficiency and the quality of machine-picked cotton fibers. Identification of the genetic components underlying defoliant sensitivity in upland cotton (Gossypium hirsutum L.) is highly important. In this study, the defoliation rate (DR) of 328 re-sequenced upland cotton accessions after 5 days of defoliant treatment was evaluated at two locations for two years in four environments;the results showed a great variation among the accessions, and the phenotype were normally distributed. A genome-wide association study (GWAS) was subsequently performed with resequencing data and defoliation rate data. As a result, two quantitative trait loci (QTL) related to defoliation rate were identified, qDS-A05 and qDS-A06, among which, qDS-A06 was identified in three environments. By combining linkage disequilibrium (LD) analysis, haplotype analysis, and expression analysis, a key candidate gene for DR was identified in qDS-A06, which was named GhDS-A06. This gene encodes a carboxylate clamp (CC)-tetratricopeptide repeat (TPR) protein, and is likely involved in the development of the abscission zone according to the reference of the function of TPR proteins in tomato (Solanum lycopersicum) and Arabidopsis (Arabidopsis thaliana L.). Additionally, the favorable haplotype frequency of GhDS-A06 varied among diverse areas of cotton growing in China, and the favorable haplotype frequency in northwestern China was much greater than that in other regions, which suggested that the favorable haplotype GhDS-A06 was artificially selected during breeding for machine-harvested cotton in northwestern China. The findings in the study not only provide genetic insights into defoliant sensitivity in upland cotton but also offer an ideal target for molecular breeding of defoliant sensitivity improved machine-harvested cotton plants.

关键词： Machine-harvested cotton Defoliation rate Genome-wide association study Favorable allele

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