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A semantic segmentation-based underwater acoustic image transmission framework for cooperative SLAM

Defence Technology（防务技术） 2024年第3期33卷 339-351页

作者： Jiaxu Li Guangyao Han Shuai Chang Xiaomei Fu School of Marine Science and Technology Tianjin UniversityTianjin 300072China

With the development of underwater sonar detection technology,simultaneous localization and mapping(SLAM)approach has attracted much attention in underwater navigation field in recent years.But the weak detection ability of a single vehicle limits the SLAM performance in wide areas.Thereby,cooperative SLAM using multiple vehicles has become an important research direction.The key factor of cooperative SLAM is timely and efficient sonar image transmission among underwater vehicles.However,the limited bandwidth of underwater acoustic channels contradicts a large amount of sonar image data.It is essential to compress the images before transmission.Recently,deep neural networks have great value in image compression by virtue of the powerful learning ability of neural networks,but the existing sonar image compression methods based on neural network usually focus on the pixel-level information without the semantic-level information.In this paper,we propose a novel underwater acoustic transmission scheme called UAT-SSIC that includes semantic segmentation-based sonar image compression(SSIC)framework and the joint source-channel codec,to improve the accuracy of the semantic information of the reconstructed sonar image at the receiver.The SSIC framework consists of Auto-Encoder structure-based sonar image compression network,which is measured by a semantic segmentation network's residual.Considering that sonar images have the characteristics of blurred target edges,the semantic segmentation network used a special dilated convolution neural network(DiCNN)to enhance segmentation accuracy by expanding the range of receptive fields.The joint source-channel codec with unequal error protection is proposed that adjusts the power level of the transmitted data,which deal with sonar image transmission error caused by the serious underwater acoustic channel.Experiment results demonstrate that our method preserves more semantic information,with advantages over existing methods at the same compression ratio.It also improves the error

关键词： Semantic segmentation Sonar image transmission Learning-based compression

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Factors affecting land dissection density in geomorphological regions of China

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Journal of Mountain Science 2024年第4期21卷 1372-1387页

作者： SUN Xiaolin ZHAO Yinjun PENG Peihao CHENG Weiming WEI Yongping YANG Ronghao li jiaxu College of Earth Sciences Chengdu University of TechnologyChengdu 610059China School of Civil Engineering Guangxi Polytechnic of ConstructionNanning 530001China Key Laboratory of Environment Change and Resources Use in Beibu Gulf Ministry of EducationNanning Normal UniversityNanning 530001China Key Laboratory of Earth Surface Process and Intelligent Simulation(Guangxi) Nanning Normal UniversityNanning 530001China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China School of Earth and Environmental Sciences The University of QueenslandBrisbane 4702Australia School of Geography and Planning Nanning Normal UniversityNanning 530001China

Land dissection density(LDD)provides morphological evidence regarding prior intense soil erosion and quantifies the distribution of land dissections.A comprehensive understanding of the potential factors influencing the spatial pattern and value of the LDD is vital in geological disasters,soil erosion,and other related domains.Land dissection phenomena in China affects large areas with different morphological,pedological,and climatic characteristics.Prior studies have focused on the potential factors influencing the LDD at a watershed scale.However,these results are insufficient to reflect the status quo of dissection development and its primary influencing factors on a national scale.LDD’s spatial patterns and the dominant factors at a regional scale in millions of square kilometers remain to be ascertained.This study used the geomorphon-based method and the geographical detector model to quantify the spatial pattern of LDD over China and identify the dominant factors affecting this pattern in China’s six first-order geomorphological regions(GR1~GR6).The results yield the following findings:(1)LDD in China ranges from 0~4.55 km/km^(2),which is larger in central and eastern regions than in other regions of China;(2)dominant factors and their dominant risk subcategories vary with each geomorphological region’s primary internal and external forces;(3)the influence of natural factors is more significant on the large regional scale in millions of square kilometers compared to anthropogenic factors;relief degree of land surface(RDLS)is dominant in GR1,GR2,and GR5;the slope is dominant in GR6,soil type is dominant in GR3 and GR4,and lithology plays a critical role in the dominant interactions of GR3,GR4,and GR6;(4)the interactions between factors on LDD’s spatial pattern have a more significant effect than individual factors.

关键词： Land dissection density Influencing factors Regional scale Spatial pattern Geographical detector model Geomorphon-based method China

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Topological pseudospin switcher:Mechanism and acoustic realization

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 46-53页

作者： Jia-He Chen Yiyin Chen Yaoqieyu Song Yongxu Xu Xinrong li Jingsong Wang Jiawei He jiaxu Qu Zheng li Xiaofei li Wenqiang lin Jiannan Chen Caixing Fu Zhi Hong Hang School of Physical Science and Technology&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou 215006China Institute for Advanced Study Soochow UniversitySuzhou 215006China Provincial Key Lab of Thin Films Soochow UniversitySuzhou 215006China

The control of the pseudospin of sound wave has attracted increasing attention in recent years.Utilizing the finite-size effect of topological acoustics,we successfully construct an H-shaped acoustic topological pseudospin switcher that sound wave energy can be easily switched through different passages.The interesting phenomenon of pseudospin flipping is numerically and experimentally demonstrated.A quantitative interference theory is proposed that the constructive and destructive interference of pseudospin states leads to pseudospin flipping and preserving in multiple frequencies.We verify the key parameters of the design,including the length of the passage and its interface state dispersion,and the theory can be extended to other topology acoustics and photonics systems.Moreover,the tunable topological sonic crystal we use provides adjustable convenience to pseudospin switcher design.The pseudospin switching behavior offers an efficient method to control the acoustic topological edge state transport,which has great potential in versatile applications,such as integrated acoustics,acoustic security,and information processing.

关键词： topological acoustics realization

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High-adhesion anionic copolymer as solid-state electrolyte for dendrite-free Zn-ion battery

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Nano Research 2022年第8期15卷 7190-7198页

作者： Jiaxu Li Junfeng Ren Caixia li Pengxian li Tingting Wu Shiwei liu Lei Wang State Key Laboratory Base of Eco-chemical Engineering Taishan Scholar Advantage and Characteristic Discipline Team of Eco-chemical Process and TechnologyQingdao University of Science and TechnologyQingdao 266042China College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China College of Environment and Safety Engineering Qingdao University of Science and TechnologyQingdao 266042China

To conquer severe dendrites formation and side reactions of zinc metal anodes,which are serious obstacles for the practical applications of aqueous zinc ion battery(ZIB),herein,we develop a sodium allysulfonate(SAS)and acrylamide(AM)copolymer by radical polymerization process(crosslinking of C=C)as solid-state electrolyte.The interface kinetics is improved remarkably due to the high adhesion and excellent ion transferability of AM-SAS(AS)copolymers.Especially the sulfonic acid group in the hydrogel electrolyte can enhance the internal ionic conductivity effectively benefiting from its high affinity to Zn^(2+).Also,polymer chains realize re-regulation to Zn^(2+)flow in atomic-scale,thus leading to controllable deposition of Zn onto the dendrite-free Zn anodes.Consequently,the AS-1.5 electrolyte achieves ultra-stable Zn deposition/stripping behaviors with the lifespan over 1,000 h via the suppression of side-reactions and paralleled Zn deposition.High performances of Zn/Mn-doped V_(2)O_(5)(MnVO)(over 500 cycles)and Zn/diquinoxalino[2,3-a:2',3'-c]phenazine(HATN)(over 2,500 cycles)full cells demonstrate that the AS hydrogel electrolyte is a common approach for ZIBs under various conditions.This molecular regulation engineering opens a novel route for hydrogel electrolyte fabrication,where sulfonic groups perform as media of Zn^(2+)transfer.Therefore,high bulk ionic conductivity as well as excellent interface ion diffusion ability is obtained.

关键词： copolymer adhesion ionic conductivity dendrite-free interface kinetics

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A Trade-off between Solvation and Collision Activation in Steering Competing E2 and S_(N)2 Dynamics

Precision Chemistry

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Precision Chemistry 2024年第1期2卷 40-48页

作者： Hongyi Wang Xu liu Siwei Zhao Gang Fu Wenqing Zhen li Yang jiaxu Zhang State Key Laboratory of Urban Water Resource and Environment MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001P.R.China College of Chemistry Liaoning UniversityShenyang 110036P.R.China

The prototypical E2 elimination and SN2 sub-stitution reactions between microsolvated fluoride and ethyl bromide show unexpected dynamic behaviors in mechanistic evolution driven by solvation and collision activation.Considering the steric effects,the gas-phase selectivity favors an E2 pathway barely dependent on collision energies.Remarkably,base solvation steers the reaction in an effective way toward substitution at a near-thermal energy,whereas the governing high-energy events retain elimination.Chemical dynamics simulations reproduce exper-imental findings and uncover a crucial solute-solvent coupling in determining such competing processes.Interestingly,collision activation can tune the underlying atomistic dynamics essentially in the reactant entrance channel and cause a mechanism shift.These features for the ubiquitous competing E2/SN2 dynamics remain quite unknown,providing unique insight into reaction selectivity for complex chemical networks.

关键词： E2/S_(N)2 Competition Atomistic Dynamics Reaction Mechanisms Microsolvation Collision Activation

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Toward Establishing a Low-cost UAV Coordinated Carbon Observation Network(LUCCN):First Integrated Campaign in China

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Advances in Atmospheric Sciences 2024年第1期41卷 1-7页

作者： Dongxu YANG Tonghui ZHAO Lu YAO Dong GUO Meng FAN Xiaoyu REN Mingge li Kai WU Jing WANG Zhaonan CAI Sisi WANG jiaxu GUO liangfu CHEN Yi liU Carbon Neutrality Research Center(CNRC) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Key Laboratory of Middle Atmospheric Physics and Global Environment Observation(LAGEO) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China State Key Laboratory of Remote Sensing Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100101China National Remote Sensing Center of China Beijing 100036China The Administrative Center for China’s Agenda 21 Beijing 100862China

In this study,we introduce our newly developed measurement-fed-perception self-adaption Low-cost UAV Coordinated Carbon Observation Network(LUCCN)prototype.The LUCCN primarily consists of two categories of instruments,including ground-based and UAV-based in-situ measurement.We use the GMP343,a low-cost non-dispersive infrared sensor,in both ground-based and UAV-based instruments.The first integrated measurement campaign took place in Shenzhen,China,4 May 2023.During the campaign,we found that LUCCN’s UAV component presented significant data-collecting advantages over its ground-based counterpart owing to the relatively high altitudes of the point emission sources,which was especially obvious at a gas power plant in Shenzhen.The emission flux was calculated by a crosssectional flux(CSF)method,the results of which differed from the Open-Data Inventory for Anthropogenic Carbon dioxide(ODIAC).The CSF result was slightly larger than others because of the low sampling rate of the whole emission cross section.The LUCCN system will be applied in future carbon monitoring campaigns to increase the spatiotemporal coverage of carbon emission information,especially in scenarios involving the detection of smaller-scale,rapidly varying sources and sinks.

关键词： CO_(2) measurement networks power station carbon emission cross-sectional flux method

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异色瓢虫人工繁育中滞育成虫的冷藏条件

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植物保护学报 2024年第1期51卷 78-87页

作者：李贝李家旭刘文王小平华中农业大学植物科学技术学院武汉430070

为延长异色瓢虫Harmonia axyridis成虫的货架期,提高规模化生产的灵活度,于室内条件下测定不同温度和光周期对异色瓢虫滞育率的影响、不同温度对异色瓢虫滞育持续时间的影响及不同冷藏温度和冷藏时间对异色瓢虫生物学特性的影响。结果表... 详细信息

为延长异色瓢虫Harmonia axyridis成虫的货架期,提高规模化生产的灵活度,于室内条件下测定不同温度和光周期对异色瓢虫滞育率的影响、不同温度对异色瓢虫滞育持续时间的影响及不同冷藏温度和冷藏时间对异色瓢虫生物学特性的影响。结果表明,在低温和短光照条件下能诱导异色瓢虫成虫滞育,当温度为20℃、光周期为10 L∶14 D时其雌、雄成虫的滞育率均高于95.0%。异色瓢虫的滞育持续时间受滞育诱导温度影响较小,在温度15℃、光周期10 L∶14 D和温度20℃、光周期10 L∶14 D两种条件下诱导的滞育异色瓢虫在温度25℃、光周期14 L∶10 D下均能快速解除滞育,在该条件下饲养10 d时其滞育解除率达90.0%以上。与8℃和12℃冷藏30 d相比,4℃冷藏30 d时异色瓢虫的存活率、总产卵量和捕食量均显著下降;当冷藏温度为12℃,冷藏时间显著影响异色瓢虫雌成虫的捕食量、寿命、产卵前期、总产卵量和卵孵化率,但对雄成虫的捕食量无显著影响。异色瓢虫冷藏期间主要以脂类和糖类作为能量物质,其冷藏期间存活率与相对总脂含量、总糖含量正相关。综上,在实际生产中异色瓢虫可在温度20℃、光周期10 L∶14 D条件下诱导滞育,在12℃冷藏90 d不会降低生物适合度。

关键词：异色瓢虫人工繁育冷藏温度冷藏时间滞育诱导

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Dynamic Load Restoration Considering the Interdependencies Between Power Distribution Systems and Urban Transportation Systems

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CSEE Journal of Power and Energy Systems 2020年第4期6卷 772-781页

作者： Ying Wang Yin Xu Jiaxu Li Chen li Jinghan He Jiayu liu Qiqi Zhang School of Electrical Engineering Beijing Jiaotong University(BJTU)Beijing 100044China State Grid Shanghai Electrical Power Company Research Institute Shanghai 200437China

After a major outage,mobile emergency resources(MERs)can be dispatched via the transportation system(TS)for service restoration to critical loads in the power distribution system(PDS).In this case study,the efficiency of service restoration in the PDS is associated with the traffic efficiency of the TS,and vice versa,because the PDS and TS are mutually coupled through traffic lights and MERs.This paper proposes a service restoration method considering interdependency between the PDS and TS,which is formulated as a mixed-integer linear program(MILP).The objective includes maximizing the efficiency of both PDS restoration and TS.By solving the MILP,the dynamic load restoration and MER dispatch strategies can be obtained.For the PDS,the availability of MERs,including mobile sources and repair crews,relates to their dispatch in the TS,and their relationship is formulated as mathematical models.For the TS,the dynamic traffic flow is modeled using the cell transmission model and the effect of traffic lights is considered.Case studies validate the effectiveness of the proposed method.

关键词： Mobile emergency resources power distribution systems resilience service restoration urban transportation systems

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九香虫的营养评价及酶解多肽制备工艺优化

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食品与机械 2024年第4期40卷 158-164页

作者：李家旭杨扬王璧莹黎攀杜冰华南农业大学食品学院广东广州510642

目的:探究九香虫营养成分组成与九香虫多肽的最佳酶解工艺条件。方法:按照国标法测定脂肪、蛋白质、总糖含量和脂肪酸组成,采用标准曲线法测定总黄酮和多酚含量;以九香虫多肽得率为指标,采用响应面法优化九香虫的酶解工艺条件;采用氨基... 详细信息

目的:探究九香虫营养成分组成与九香虫多肽的最佳酶解工艺条件。方法:按照国标法测定脂肪、蛋白质、总糖含量和脂肪酸组成,采用标准曲线法测定总黄酮和多酚含量;以九香虫多肽得率为指标,采用响应面法优化九香虫的酶解工艺条件;采用氨基酸分析仪、高效凝胶渗透色谱法测定九香虫酶解物的氨基酸组成和相对分子质量分布;考察九香虫酶解物对DPPH自由基和ABTS+自由基的清除能力及总还原能力。结果:九香虫粗脂肪含量为43.40%,蛋白质含量为37.08%,总糖含量为7.64%,总黄酮含量为1.67%,总酚含量为1.90%;九香虫最佳酶解工艺为蒸煮时间5 h,酶解pH 10,酶解时间6 h,酶解温度55℃,该条件下多肽得率为35.74%;九香虫酶解物必需氨基酸和非必需氨基酸的比值为70.46%,九香虫酶解物相对分子质量<1000所占比例为88.1%;九香虫酶解物质量浓度为1.0 mg/mL时ABTS+自由基清除率达到88.44%。结论:在最佳酶解工艺下,九香虫多肽得率为35.74%,具有较高的营养价值和较好的抗氧化活性。

关键词：九香虫酶解氨基酸组成相对分子质量抗氧化多肽

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列车齿轮箱新型轴端密封结构参数优化设计

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润滑与密封 2024年第2期49卷 131-136页

作者：林佳旭沙智华李宝良大连交通大学机械工程学院辽宁大连116028

为进一步提升列车齿轮箱轴承端盖处密封结构的密封效果,有效阻止减速器内外流体交换,在前期设计的密封结构基础上,对两侧叶轮的内径、叶片两侧倾角、叶片底部倾角、叶片侧边倒圆角以及中部叶轮叶片数目等密封结构参数进行优化分析。结... 详细信息

为进一步提升列车齿轮箱轴承端盖处密封结构的密封效果,有效阻止减速器内外流体交换,在前期设计的密封结构基础上,对两侧叶轮的内径、叶片两侧倾角、叶片底部倾角、叶片侧边倒圆角以及中部叶轮叶片数目等密封结构参数进行优化分析。结合流体动力学分析结果及前期实验数据,探究各参数对密封效果的影响。结果表明:两侧叶轮叶片内径、叶片侧面倾角对密封效果影响较大,其他参数对密封效果影响较小;相较于原密封结构,优化设计后轴端密封结构中部叶轮相对两侧叶轮的关键平面平均压差从22.97 Pa提升至357.94 Pa,且从速度流线图可以看出在密封结构中部会形成明显的隔离区,能有效阻止齿轮箱内外流体沟通,提升轴端密封性能。

关键词：齿轮箱轴端密封叶片倾角速度流线图

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