3D Shape Recognition Based on Multimodal \newline Relation Modeling

To make full use of the local spatial relation between point cloud and multi-view data to further improve the accuracy of three-dimensional (3D) shape recognition, a 3D shape recognition network based on multimodal relation is proposed. Firstly, a Multimodal Relation Module (MRM) is designed, which can extract the relation information between the local features of any point cloud and that of any multi-view to obtain the corresponding relation features. Then, a cascade pooling consisting of maximum pooling and generalized mean pooling is applied to process the relation feature tensor and obtain the global relation feature. There are two types of multimodal relation modules, which output the point-view relation feature and the view-point relation feature, respectively. The proposed gating module adopts a self-attentive mechanism to find the relation information within the features so that the aggregated global features can be weighted to suppress redundant information. Extensive experiments show that the multimodal relation module can make the network obtain stronger representational ability; the gating module can make the final global feature more discriminative and boost the performance of the retrieval task. The proposed network achieves classification accuracy of 93.8% and 95.0%, as well as average retrieval precision of 90.5% and 93.4% on two standard 3D shape recognition datasets (ModelNet40 and ModelNet10), respectively, which outperforms the existing works.     

Chemical Coupled PEDOT:PSS/Si Electrode: Suppressed Electrolyte Consumption Enables Long‑Term Stability

Huge volume changes of Si during lithiation/delithiation lead to regeneration of solid-electrolyte interphase(SEI)and consume electrolyte.In this article,γ-glycidoxypropyl trimethoxysilane(GOPS)was incorporated in Si/PEDOT:PSS electrodes to construct a flexible and conductive artificial SEI,effectively suppressing the consumption of electrolyte.The optimized electrode can maintain 1000 mAh g^−1 for nearly 800 cycles under limited electrolyte compared with 40 cycles of the electrodes without GOPS.Also,the optimized electrode exhibits excellent rate capability.The use of GOPS greatly improves the interface compatibility between Si and PEDOT:PSS.XPS Ar+etching depth analysis proved that the addition of GOPS is conducive to forming a more stable SEI.A full battery assembled with NCM 523 cathode delivers a high energy density of 520 Wh kg^−1,offering good stability.     

GNSS技术与多传感器融合的滑坡监测系统研究

本文设计了一种基于GNSS技术与多传感器融合的滑坡监测系统,该系统采用低功耗设计思路,通过RT-Thread操作系统实现多任务处理与低功耗模式运行,具有与滑坡监测预警云平台通信、GNSS网络RTK实时动态高精度定位、多传感器融合、监测数据实时采集处理、滑坡地质灾害预警等功能。实验结果表明,该系统运行功耗低、数据传输速度快、可靠性高、位移监测精度可达毫米级,满足对滑坡体进行高精度变形监测预警的需求。     

A vacuum ultraviolet laser with a submicrometer spot for spatially resolved photoemission spectroscopy

Vacuum ultraviolet(VUV)lasers have demonstrated great potential as the light source for various spectroscopies,which,if they can be focused into a small beam spot,will not only allow investigation of mesoscopic materials and structures but also find application in the manufacture of nano-objects with excellent precision.In this work,we report the construction of a 177 nm VUV laser that can achieve a record-small(〜0.76 μm)focal spot at a long focal length(~45 mm)by using a flat lens without spherical aberration.The size of the beam spot of this VUV laser was tested using a metal grating and exfoliated graphene flakes,and we demonstrated its application in a fluorescence spectroscopy study on pure and Tm3+-doped NaYF4 microcrystals,revealing a new emission band that cannot be observed in the traditional up-conversion process.In addition,this laser system would be an ideal light source for spatially and angleresolved photoemission spectroscopy.     

Maternal Prenatal Inflammation Increases Brain Damage Susceptibility of Lipopolysaccharide in Adult Rat Offspring via COX-2/PGD-2/DPs Pathway Activation

A growing body of research suggests that inflammatory insult contributes to the etiology of central nervous system diseases, such as depression, Alzheimer’s disease, and so forth. However, the effect of prenatal systemic inflammation exposure on offspring brain development and cerebral susceptibility to inflammatory insult remains unknown. In this study, we utilized the prenatal inflammatory insult model in vivo and the neuronal damage model in vitro. The results obtained show that prenatal maternal inflammation exacerbates LPS-induced memory impairment, neuronal necrosis, brain inflammatory response, and significantly increases protein expressions of COX-2, DP2, APP, and Aβ, while obviously decreasing that of DP1 and the exploratory behaviors of offspring rats. Meloxicam significantly inhibited memory impairment, neuronal necrosis, oxidative stress, and inflammatory response, and down-regulated the expressions of APP, Aβ, COX-2, and DP2, whereas significantly increased exploring behaviors and the expression of DP1 in vivo. Collectively, these findings suggested that maternal inflammation could cause offspring suffering from inflammatory and behavioral disorders and increase the susceptibility of offspring to cerebral pathological factors, accompanied by COX-2/PGD-2/DPs pathway activation, which could be ameliorated significantly by COX-2 inhibitor meloxicam treatment.     

基于TDD的低轨卫星跳波束资源分配算法

低轨(LEO)卫星跳波束技术可以灵活分配系统资源,适用于业务分布不均匀的场景。时分双工(TDD)方式可以减少星载和地面终端设备的天线数量,有效降低其复杂度,并有利于开展上下行非对称业务。本文提出一种基于TDD的LEO卫星跳波束资源分配算法,在满足业务需求的基础上,以最小化时域资源消耗为目标,建立支持跳波束和多频时分多址接入(MF-TDMA)机制的LEO卫星反向链路资源分配模型;综合考虑星地动态时延补偿,采取一种多层次的跳波束时隙架构设计,以最大化可用时隙为目标,建立上下行时隙切换模型,并提出一种基于TDD的跳波束时隙排布优化方法。仿真结果表明,对比于传统的MF-TDMA资源分配方法或固定多波束均分算法,本文提出的算法能有效提高系统的时隙利用率和吞吐量。     

Experimental study of flow patterns and improved configurations for pulsating heat pipes

A series of experiments were performed on three types of closed loop pulsating heat pipes(PHPs),intending toinvestigate various kinds of flow patterns,and to develop some improved configurations for the PHPs.Opticalvisualization results indicated that there might exist three flow patterns,i.e.bubble-liquid slug flow,semi-annularflow and annular flow,corresponding to different working conditions.For a given geometry and an adequate fillratio,the PHPs had the self-adjusting characteristic for the flow patterns(from slug flow to semi-annular and thento annular flow)to meet the demands of the increasing heat input.Two special configurations,one with alter-nately varying channel diameter,the other equipped with one section of thicker tube,were found to be advanta-geous in establishing and maintaining reliable circulation of the working fluid.The thermal performance of thePHPs was examined over a range of working conditions.Comparing with the normal PHP with uniform diameter,either of the improved PHPs exhibited higher thermal performance.     

摩擦改进剂对改善燃油经济性的影响研究

采用四球机试验,考察了钼胺化合物、二烷基二硫代氨基甲酸钼、无灰型摩擦改进剂与摩擦因数的关系以及它们之间的复配作用。结果表明：摩擦改进剂（FM）降低摩擦因数的效果与其化学结构有关;加入量提高,摩擦因数的改善效果明显;不同化学结构的摩擦改进剂复配使用,可以减低整个温度区的摩擦因数。     

大规格石材块料的板材薄切工艺

当今,石材薄板的加工与应用已成为发展的方向。因为这对节省资源和能源,提高资源利用率,减轻建筑物负重,降低运输和施工费用起着十分重要的作用。因此,十分有必要突破石材“瘦身”的技术瓶颈问题。笔者编译了国外文献中有关石材块料薄切工艺的文章,推荐给读者,以供借鉴。