一种结合阴影补偿的城市高分遥感影像分割方法

随着遥感影像空间分辨率的不断提高,由于阴影导致的弱边缘及虚假边缘等对于准确定位对象边缘所造成的干扰也更加突出。在传统的影像分割中进一步引入阴影补偿策略,在之前所提出的WJSEG算法基础上,通过将阴影视为出界点并利用卡方变换进行阴影识别,提出了一种结合阴影补偿的城市场景高分辨率遥感影像分割算法SWJSEG。实验表明,该方法能够有效应对阴影造成的干扰,有助于更加准确地定位对象边缘,使影像分割的精度及可靠性显著提高。     

Influence of Dy-doping on ferroelectric and dielectric properties in Bi<Subscript>1.05−x</Subscript>Dy<Subscript>x</Subscript>FeO<Subscript>3</Subscript> ceramics

Bi_1.05−xDy_xFeO₃ (BDFO) (x = 0−0.2) ceramics were synthesized by solid-state reaction method. The influence of Dy dopant on crystal structural, dielectric and ferroelectric properties was investigated. The lattice parameter and the Curie temperature of BDFO were degraded continuously with increasing contents of Dy³⁺ cations. Leakage current density, ferroelectric polarization and dielectric loss were improved by appropriate Dy doping. When x = 0.1, BDFO showed the best electric properties. At applied electric field of 53 kV/cm, the remnant polarization (2P _r ) was 12.2 μC/cm².These improvements in electric properties in BDFO ceramics could have resulted from the relatively low oxygen vacancy concentration and structural distortion.     

异步被动传感器航迹起始算法

航迹起始是多目标航迹处理中的重要问题.针对异步被动传感器系统航迹起始困难的问题,提出了一种基于蚁群导航思想的异步被动传感器航迹起始算法.该算法首先利用各传感器在多个扫描周期的测量建立候选目标集,采用极大似然法确定每一个候选目标的初始状态估计,然后再利用蚁群导航算法实现真实航迹的检测,最后由极大似然法估计出每一批目标的初...     

某工程湿陷性黄土地基处理方案比选

湿陷性黄土地基处理的方法主要有强夯法、换土垫层法、灰土挤密桩复合地基、桩基础等,每种方法均有其优缺点和适用范围。本文结合实际工程,对湿陷性黄土地基处理方案进行技术与经济比选,并讨论了湿陷性黄土地基处理的关键问题。     

焊线机超声波闭环控制

超声波是焊线机焊接过程中的重要参与元素,超声波控制效果决定着焊接的品质和速度。在分析超声换能器频率特性和电流响应的基础上,给出了频率自动跟踪和电流受控输出的闭环控制方案,提高了超声波效率,缩短了响应时间,增强了超声波输出的稳定性。实验结果表明,此方法实现了受控的上升时间和较小的超调     

Carbon Nanotube‐Encapsulated Noble Metal Nanoparticle Hybrid as a Cathode Material for Li‐Oxygen Batteries

Although Li‐oxygen batteries offer extremely high theoretical specific energy, their practical application still faces critical challenges. One of the main obstacles is the high charge overpotential caused by sluggish kinetics of charge transfer that is closely related to the morphology of discharge products and their distribution on the cathode. Here, a series of noble metal nanoparticles (Pd, Pt, Ru and Au) are encapsulated inside end‐opened carbon nanotubes (CNTs) by wet impregnation followed by thermal annealing. The resultant cathode materials exhibit a dramatic reduction of charge overpotentials compared to their counterparts with nanoparticles supported on CNT surface. Notably, the charge overpotential can be as low as 0.3 V when CNT‐encapsulated Pd nanoparticles are used on the cathode. The cathode also shows good stability during discharge–charge cycling. Density functional theory (DFT) calculations reveal that encapsulation of “guest” noble metal nanoparticles in “host” CNTs is able to strengthen the electron density on CNT surfaces, and to avoid the regional enrichment of electron density caused by the direct exposure of nanoparticles on CNT surface. These unique properties ensure the uniform coverage of Li₂O₂ nanocrystals on CNT surfaces instead of localized distribution of Li₂O₂ aggregation, thus providing efficient charge transfer for the decomposition of Li₂O₂.     

深水盐下湖相碳酸盐岩缝洞地震预测

桑托斯盆地F油田位于巴西深水区域的盐岩之下,具有埋藏深、岩性多样、非均质性强的特点。与常规的以孔隙型为主的储层和中国西部“串珠状”的大型溶洞储层不同,研究区碳酸盐岩为深水盐下湖相碳酸盐岩,其溶蚀孔洞孔径小、裂缝类型多,导致地震响应特征极其不明显,常规缝洞预测方法不适用。另外,受上覆巨厚盐岩层的影响,缝洞发育储层段的地震资料分辨率低,增加了利用叠后地震方法预测其分布规律的难度。因此,针对研究区缝洞发育特点,采取井震相结合的思路,以消除泥岩及火成岩岩性干扰为前提,首先进行地震资料优化处理,然后充分利用岩心、FMI测井等资料以及生产漏失等信息,综合分析地震异常可能表达的地质信息,探索了一套适用于深水盐下多种岩性发育背景的小尺度湖相碳酸盐岩缝洞储层地震预测方法。该方法明确了裂缝与孔洞的敏感地震属性,通过联合构造应力场进行裂缝预测,结合波阻抗、孔隙度及CGR等地震反演结果,开展溶蚀孔洞预测,取得了良好的预测效果,对湖相碳酸盐岩缝洞储层预测研究有借鉴意义。     

高温气冷堆控制棒B4C芯块的研制

阐述了用电弧炉碳热还原法制备核级B4C粉末、经热压烧结制备高温气冷堆控制棒B4C芯块的研制过程，研究了添加剂对制备B4C芯块的影响。     

过渡金属氧化物LaFe1-xCrxO3体系的晶体结构和光电子能谱研究

我们在端点化合物LaFeO3中掺入Cr^3 ，制备了LaFe1-xCrxO3体系的系列样品。经XRD分析证明所制备的样品为单相体系，用MarqX程序对XRD数据进行分析得到其晶格常数。分别测定了入射光子能量在Fe2p吸收边以下和以上的O1s芯能级谱。从电子结构角度探讨了该体系晶体结构变化趋势。初步得出结论：随着Cr^3 掺杂量在LaFe1-xCrxO3中的增加，O2p向Cr 3d的电荷转移量也发生有规律的变化。     

坦克机动性虚拟试验研究

主要研究了虚拟环境中军用车辆特别是坦克机动性虚拟试验时动力学模型的建立，建立了虚拟环境下坦克的实时动力学模型，并且描述了整个虚拟试验视景仿真系统的组成及其实现过程。