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Hybrid pedestrian positioning system using wearable inertial sensors and ultrasonic ranging

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Defence Technology（防务技术） 2024年第3期33卷 327-338页

作者： Lin Qi yu Liu Chuanshun Gao Tao Feng yue yu School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic UniversityHong Kong 999077China

Pedestrian positioning system(PPS)using wearable inertial sensors has wide applications towards various emerging fields such as smart healthcare,emergency rescue,soldier positioning,*** performance of traditional PPS is limited by the cumulative error of inertial sensors,complex motion modes of pedestrians,and the low robustness of the multi-sensor collaboration *** paper presents a hybrid pedestrian positioning system using the combination of wearable inertial sensors and ultrasonic ranging(H-PPS).A robust two nodes integration structure is developed to adaptively combine the motion data acquired from the single waist-mounted and foot-mounted node,and enhanced by a novel ellipsoid constraint *** addition,a deep-learning-based walking speed estimator is proposed by considering all the motion features provided by different nodes,which effectively reduces the cumulative error originating from inertial ***,a comprehensive data and model dual-driven model is presented to effectively combine the motion data provided by different sensor nodes and walking speed estimator,and multi-level constraints are extracted to further improve the performance of the overall *** results indicate that the proposed H-PPS significantly improves the performance of the single PPS and outperforms existing algorithms in accuracy index under complex indoor scenarios.

关键词： Pedestrian positioning system Wearable inertial sensors Ultrasonic ranging Deep-learning Data and model dual-driven

Ignition processes and characteristics of charring conductive polymers with a cavity geometry in precombustion chamber for applications in micro/nano satellite hybrid rocket motors

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Defence Technology（防务技术） 2024年第2期32卷 55-66页

作者： Zhiyuan Zhang Hanyu Deng Wenhe Liao Bin yu Zai yu Nanjing University of Science and Technology Nanjing 210094China

The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano ***,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical *** conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition *** this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was *** detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were *** ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition *** results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition ***,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of *** the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,*** rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition *** to direct injection scheme,swirlin

关键词： Micro/nano satellite hybrid propulsion Arc ignition Charring conductive polymer Ignition mechanism Ignition characteristic Repeated ignition

Heat Transfer Characteristics of a Microchannel Heat Sink with Highly-Dense Micro-Jet Arrays

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Journal of Thermal Science 2024年第3期33卷 1148-1160页

作者： ZHANG yu CHEN Xiaoyan MIAO Lin CHEN Liang HOU yu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China Beijing Aerospace Technology Institute Beijing100083China

This paper proposed a new structure of highly-dense micro-jet arrays for hybrid jet-impingement/microchannel heat sinks(~120 jet per cm^(2) with jet width of 0.35 mm).Parametric study is performed to investigate the influence of structure and flow parameters on the convective heat transfer of water jet cooling in confined *** simulation results show that the optimal jet width,jet spacing and impingement distance are around 0.2 mm,0.2 mm and 0.3 mm,respectively,which can achieve a low thermal resistance as well as a relatively low pressure *** analysis of the heat transfer pathways shows that the micro-fin jet structures can extend the impinging heat transfer area and conduct a considerable proportion of heat,which can reach up to 38.9%with the Reynolds number ranging from 797.1 to *** heat transfer characteristics in the heat sink will shift from impingement dominated heat transfer to the channel-convection dominated heat transfer as the jet impingement distance increases.A correlation is proposed to predict the average Nusselt number on the stagnation area for the heat sink with different structure parameters,and the deviations of predictions from the numerical results are less than 10%.

关键词： hybrid heat sink impingement microchannel thermal management high heat flux

Chord length sampling correction analysis for dispersion fuel in Monte Carlo simulation

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Nuclear Science and Techniques 2024年第4期35卷 57-64页

作者： Zhao-yu Liang Ding She yu-Tong Wen Lei Shi Institute of Nuclear and New Energy Technology(INET) Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China

Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled *** with deterministic methods,the Monte Carlo method has more advantages in the geometric modeling of stochastic *** explicit modeling method has high computational accuracy and high computational *** chord length sampling(CLS)method can improve computational efficiency by sampling the chord length during neutron transport using the matrix chord length?s probability density *** study shows that the excluded-volume effect in realistic stochastic media can introduce certain deviations into the CLS.A chord length correction approach is proposed to obtain the chord length correction factor by developing the Particle code based on equivalent transmission *** numerical analysis against reference solutions from explicit modeling in the RMC code,it was demonstrated that CLS with the proposed correction method provides good accuracy for addressing the excludedvolume effect in realistic infinite stochastic media.

关键词： Stochastic media Monte Carlo Chord length sampling Excluded-volume effect Chord length correction

Research on the mechanism of the two-dimensional ultrasonic surface burnishing process to enhance the wear resistance for aluminum alloy

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Friction 2024年第3期12卷 490-509页

作者： Zhen-yu ZHOU Qiu-Yang ZHENG yu LI Cong DING Guang-Jian PENG Zhong-yu PIAO College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of Education and Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310014China

The gradient nanostructure is machined on the aluminum(Al)alloy by the two-dimensional ultrasonic surface burnishing process(2D-USBP).The mechanism of why the gradient nanostructure enhances wear resistance is *** mechanical properties and microstructure characterization for the gradient nanostructure are performed by operating a nanoindenter,transmission electron microscopy(TEM),and electron backscattered diffraction(EBSD).Dry wear tests are performed on the samples before and after machining to evaluate the wear resistance and *** effect of the gradient nanostructure on the wear resistance is explored by developing the crystal plasticity(CP)finite element and molecular dynamics(MD)*** characterization results show that the 2D-USBP sample prepared a gradient structure of~600μm thick on the aluminum surface,increasing the surface hardness from 1.13 to 1.71 GPa and reducing the elastic modulus from 78.84 to 70.14 *** optimization of the surface microstructure and the increase of the mechanical properties effectively enhance the wear resistance of the sample,with 41.20%,39.07%,and 54.58% of the wear scar areas for the 2D-USBP treated samples to the original samples under 5,10,and 15 N loads,*** gradient nanostructure hinders the slip of dislocations inside the sample during the wear process and reduces the size and scope of plastic deformation;meanwhile,the resistance to deformation,adhesion,and crack initiation and propagation of the sample surface is improved,resulting in enhanced wear resistance.

关键词： structural superlubricity lattice registry elastic deformation strained solitons crystal plasticity molecular dynamics simulations

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氢气对重度烧伤小鼠早期肺损伤的影响

中华烧伤杂志 2017年第11期33卷 682-687页

作者：秦超边映雪冯甜甜张金辉于泳浩天津医科大学总医院麻醉科天津市麻醉学研究所300052 南开大学附属医院(天津市第四医院)麻醉科

目的探讨氢气对重度烧伤小鼠早期肺损伤的影响。方法取160只ICR小鼠，按随机数字表法分为假伤组、氢气组、单纯烧伤组、烧伤＋氢气组，每组40只。单纯烧伤组和烧伤＋氢气组小鼠背部制作40%TBSA Ⅲ度烫伤（以下称烧伤）模型，假伤组和氢... 详细信息

目的探讨氢气对重度烧伤小鼠早期肺损伤的影响。方法取160只ICR小鼠，按随机数字表法分为假伤组、氢气组、单纯烧伤组、烧伤＋氢气组，每组40只。单纯烧伤组和烧伤＋氢气组小鼠背部制作40%TBSA Ⅲ度烫伤（以下称烧伤）模型，假伤组和氢气组小鼠模拟致假伤。分别于伤后1、6 h，氢气组和烧伤＋氢气组小鼠吸入体积分数2%氢气1 h，假伤组和单纯烧伤组小鼠吸入空气1 h。伤后24 h，各组取6只小鼠肺组织，行HE染色，观察肺组织病理变化，并计算肺组织损伤病理学评分。各组另取8只小鼠，取下腔静脉血和肺组织，采用ELISA法检测血清和肺组织中高迁移率族蛋白B1（HMGB1）、IL－6的含量，分光光度法检测血清和肺组织中SOD活性。各组另取6只小鼠，取动脉血测定PaO2，取肺组织，称量肺湿干质量，计算肺湿干质量比。计算各组剩余20只小鼠伤后7 d内的存活率。对数据行单因素方差分析、LSD检验和log－rank检验。结果（1）伤后24 h，假伤组和氢气组小鼠肺组织未见异常；单纯烧伤组小鼠肺间质水肿，肺泡毛细血管壁严重破裂，出现大量炎性细胞浸润；烧伤＋氢气组小鼠肺间质轻度水肿，肺泡毛细血管充血伴少量破裂出血，炎性细胞浸润较单纯烧伤组少。假伤组、氢气组、单纯烧伤组和烧伤＋氢气组小鼠肺组织损伤病理学评分分别为（0.7±0.5）、（0.8±0.5）、（6.1±1.0）、（2.8±0.8）分，单纯烧伤组小鼠肺组织损伤病理学评分较假伤组显著升高（P〈0.001），烧伤＋氢气组小鼠肺组织损伤病理学评分较单纯烧伤组显著降低（P〈0.001）。（2）伤后24 h，氢气组小鼠血清和肺组织中HMGB1、IL－6含量与假伤组相近（P值均大于0.05），单纯烧伤组小鼠血清和肺组织中HMGB1、IL－6含量较假伤组显著升高（P值均小于0.001），烧伤＋氢气组小鼠血清和肺组织中HMGB1、IL－6含量较单纯烧伤组显著降低（P值均小于0.001）。（3）伤后24 h，氢气组小鼠血清和肺组织中SOD活性与假伤组相近（P值均大于0.05），单纯烧伤组小鼠血清和肺组织中SOD活性较假伤组显著降低（P值均小于0.001），烧伤＋氢气组小鼠血清和肺组织中SOD活性较单纯烧伤组显著升高（P值均小于0.001）。（4）伤后24 h，4组小鼠PaO2总体比较，差异无统计学意义（F＝0.04，P〉0.05）。（5）伤后24 h，假伤组、氢气组、单纯烧伤组和烧伤＋氢气组小鼠肺湿干质量比分别为3.52±0.22、3.61±0.24、7.24±0.32、5.21±0.41，单纯烧伤组小鼠肺湿干质量比明显高于假伤组（P〈0.001），烧伤＋氢气组小鼠肺湿干质量比明显低于单纯烧伤组（P〈0.001）。（6）假伤组和氢气组小鼠伤后7 d内存活率为100%。与假伤组比较，单纯烧伤组小鼠伤后3～7 d存活率均明显降低（P值均小于0.05）。与单纯烧伤组比较，烧伤＋氢气组小鼠伤后5～7 d存活率明显升高（P值均小于0.05）。结论氢气能够显著减轻重度烧伤小鼠肺组织炎性细胞浸润和改善肺组织病理损伤，具有减轻炎症反应、抑制氧化应激的作用，进而对烧伤小鼠肺起到了保护作用。

关键词：烧伤肺 HMGB1蛋白白细胞介素6 超氧化物歧化酶氢气

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氙气吸入麻醉的研究进展

医学综述 2020年第3期26卷 577-580,585页

作者：田婧于泳浩天津医科大学总医院麻醉科天津市麻醉学研究所

氙气吸入麻醉的相关研究已开展了70余年,目前人类对氙气的药理学性质、麻醉机制和临床应用等都有了更为深刻的认识。氙气是一种稀有的惰性气体,主要通过与N-甲基-D-天冬氨酸受体结合发挥镇痛作用,且氙分子结构稳定,自身不易发生反应,故... 详细信息

氙气吸入麻醉的相关研究已开展了70余年,目前人类对氙气的药理学性质、麻醉机制和临床应用等都有了更为深刻的认识。氙气是一种稀有的惰性气体,主要通过与N-甲基-D-天冬氨酸受体结合发挥镇痛作用,且氙分子结构稳定,自身不易发生反应,故对机体的影响相对较小。氙气能够稳定术中血流动力学,还具有重要器官保护作用,具备理想吸入麻醉药的诸多特性,然而由于价格昂贵,氙气的研究和应用受到制约。但随着人类对氙气认识的不断加深以及医学科技的日益进步,氙气在临床麻醉应用中已逐渐受到重视。

关键词：吸入麻醉药氙气全身麻醉

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基于叶片匹配的作物植株图像分离与计数方法

江苏大学学报（自然科学版） 2023年第3期44卷 293-301页

作者：张连宽肖德琴岑冠军于永浩华南农业大学数学与信息学院广东广州510642 广西作物病虫害生物学重点实验室广西南宁530007

构建了从连续采集的田间图像中提取作物植株的算法,为图像采集植株微观生长信息提供算法支撑.首先,从图像中分割出叶片,根据叶片距离分离出单个植株;将连续相邻的两幅图像进行拼接获得拼接变换,并将两幅图像中各植株图像与空图像按照获... 详细信息

构建了从连续采集的田间图像中提取作物植株的算法,为图像采集植株微观生长信息提供算法支撑.首先,从图像中分割出叶片,根据叶片距离分离出单个植株;将连续相邻的两幅图像进行拼接获得拼接变换,并将两幅图像中各植株图像与空图像按照获得的拼接变换计算出植株拼接变换图;其次,求出各株拼接变换图的叶片图像质心,采用距离门限的方法判断两植株图像是否为同株作物;在此基础上,采用传递闭包获得各株作物在不同图像中的集合,并用距离中心最小的方法从各株集合中选择出最佳图像,用5种作物对该算法进行验证,结果表明:株数检测准确率达到了100%,提出的方法也成功地将各植株图像精确地提取出来,同时算法显示出高效的计算效率.

关键词：作物机器视觉图像采集叶片匹配图像拼接

瑞马唑仑和咪达唑仑对健康老龄大鼠认知功能影响的比较

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中华麻醉学杂志 2020年第9期40卷 1089-1092页

作者：史媛蒋毅董贝贝谢克亮于泳浩天津医科大学总医院麻醉科 300052

目的比较瑞马唑仑和咪达唑仑对健康老龄大鼠认知功能的影响。方法清洁级健康老龄雄性Wistar大鼠30只,18~20月龄,体重600~650 g,采用随机数字表法分为3组(n=10):对照组(C组)、咪达唑仑组(M组)和瑞马唑仑组(R组)。尾静脉置管后,M组给予咪... 详细信息

目的比较瑞马唑仑和咪达唑仑对健康老龄大鼠认知功能的影响。方法清洁级健康老龄雄性Wistar大鼠30只,18~20月龄,体重600~650 g,采用随机数字表法分为3组(n=10):对照组(C组)、咪达唑仑组(M组)和瑞马唑仑组(R组)。尾静脉置管后,M组给予咪达唑仑25 mg/kg负荷剂量,维持剂量3~6 mg·kg-1·h-1;R组给予瑞马唑仑25 mg/kg负荷剂量,维持剂量60~120 mg·kg-1·h-1,连续5 d,每天连续输注8 h,C组给予等量生理盐水。停药后第1、3和7天进行Y迷宫实验,记录新异臂停留时间和各个臂穿梭次数总和。进行场景恐惧和声音恐惧条件实验,计算僵直时间比率;末次Y迷宫实验后即刻处死大鼠取海马组织,采用Western blot法测定Tau蛋白、p-Tau蛋白和载脂蛋白E(ApoE)的表达。结果与C组比较,M组和R组新异臂停留时间缩短,各个臂穿梭次数总和减少,场景恐惧条件实验的僵直时间比率降低,海马Tau蛋白、p-Tau蛋白和ApoE表达上调(P<0.05);与M组比较,R组新异臂停留时间延长,各个臂穿梭次数总和增加,场景恐惧条件实验的僵直时间比率升高,海马Tau蛋白、p-Tau蛋白和ApoE表达下调(P<0.05)。结论与咪达唑仑比较,瑞马唑仑对健康老龄大鼠认知功能的影响较小,与上调海马ApoE表达,导致Tau蛋白磷酸化的程度不同有关。

关键词：苯二氮䓬类认知老年人