深度卷积网络卫星图像水泥厂目标检测

目的 水泥厂作为重要的污染源企业需要对其进行统计和监管,近几年随着卫星遥感技术的发展和遥感影像分辨率的提高,使得基于卫星影像进行水泥厂目标检测成为可能。但是由于遥感图像中建筑目标的环境复杂多变,同时各个水泥厂在生产规模、设备构成、厂区结构、坐落方位上存在较大差异,图像表观上的形态各异和复杂环境干扰使得传统图像识别方法难以设计和提取有效特征。鉴于深度学习在视觉目标检测领域的成功应用,本文将研究应用深度卷积神经网络方法,实现在卫星图像上识别与定位水泥厂目标,为环保部门提供一种高效便捷的水泥厂目标检测和统计方法。方法 基于面向目标检测与定位的Faster R-CNN深度学习框架,以准确检测与定位水泥厂区域为目的,以京津冀地区的水泥厂位置作为训练和测试数据集,选用3种结构不同的提取特征卷积神经网络模型进行了对比实验。并针对小样本训练容易出现的过拟合和误检问题,采用图像去雾预处理、数据扩充、引入负样本等技术进一步提升模型能力。结果 测试集实验结果表明ResNet特征提取网络效果最好,准确率达到74%。为了进一步提高检出率并降低误检率,引入3种模型能力提升方法,在扩充检测数据集中的检出率达到94%,误检率降低到14%;在全球水泥厂数据集中的图像检出率达到96%,万幅随机图像的误检数量为30幅（0.3%）。对上海地区的卫星图像进行扫描检测,结果检测出11个已登记的水泥厂（共登记16个）,另外还检测出17个未登记的水泥厂。结论 对于卫星地图上水泥厂这种具有特殊建筑构造但也存在厂区几何形状各异、所处地理环境复杂、随季节性变化等特点,本文提出的基于深度卷积网络的卫星图像水泥厂检测方法,能够自动学习提取有效的图像特征并对目标进行准确检测。针对小样本训练问题,引入3种方法显著提高了模型的检测精度。在模型泛化能力测试中,经过优化后的模型在水泥厂建筑目标检测任务中表现良好,具有重要的应用价值。     

现代数字卫星广播用的先进数字技术及发展趋势

数字式电视卫星广播的基本特征是服务的灵活性和功率的节约，它与模拟式比较，更具有经济价值且切实可行．数字式电视卫星广播的发展趋势是：（１）在现有的模拟式基础上传播高音质立体声或双语音电视广播；（２）数字式直接卫星电视广播；（３）高清晰度数字式电视广播．     

Quantitative atomic structure determination from HREM: viewpoints on accuracy and reliability

The state of the art of atomic structure determination from HREM is discussed in the framework of parameter estimation. The role of direct holographic methods is to yield a starting structure for further quantitative refinement. The reason for the quantitative mismatch between theoretical and experimental images is discussed and an improved algorithm is suggested to speed up the calculations.     

Arsenic incorporation in InAsP/InP quantum wells

InAsP/InP multiquantum well structures were grown by solid source molecular beam epitaxy using either As₂ or As₄ over a substrate temperature range of 420–535°C. All quantum wells had similar arsenic compositions with a 2.2% standard deviation regardless of arsenic species or growth temperature. This temperature insensitivity of arsenic incorporation in InAsP is in sharp contrast to InGaAsP in which arsenic composition is very sensitive to both substrate temperature and gallium percentage in the compound. The insensitivity of arsenic incorporation in InAsP to substrate temperature may result from growth in a phosphorus rich condition with indium as the only available cation.     

塔巴庙区块山西组高分辨率层序地层学研究

以高分辨率层序地层学理论为指导,以露头剖面、钻井岩心、测井资料的综合研究为基础,研究了塔巴庙区块下二叠统山西组的高分辨率层序地层学特征,识别和划分了一个超长期、两个长期、六个中期及若干个短期基准面旋回层序。详细分析了不同级次基准面旋回层序的叠加式样、沉积序列、岩性岩相组合等特征。在此基础上,讨论了基准面旋回层序与天然气富集的关系,认为主要气层段主要处于长期及中期旋回的底部,即基准面上升阶段的早期或湖平面下降的低水位时期及湖侵期的开始时期。     

Investigation of microstructure and V-defect formation in In<Subscript>x</Subscript>Ga<Subscript>1−x</Subscript>N/GaN MQW grown using temperature-gradient metalorganic chemical vapor deposition

Temperature-gradient metalorganic chemical vapor deposition (MOCVD) was used to deposit In_xGa_1−xN/GaN multiple quantum well (MQW) structures with a concentration gradient of indium across the wafer. These MQW structures were deposited on low defect density (2×10⁸ cm⁻²) GaN template layers for investigation of microstructural properties and V-defect (pinhole) formation. Room temperature (RT) photoluminescence (PL) and photomodulated transmission (PT) were used for optical characterization, which show a systematic decrease in emission energy for a decrease in growth temperature. Triple-axis x-ray diffraction (XRD), scanning electron microscopy, and cross-sectional transmission electron microscopy were used to obtain microstructural properties of different regions across the wafer. Results show that there is a decrease in crystal quality and an increase in V-defect formation with increasing indium concentration. A direct correlation was found between V-defect density and growth temperature due to increased strain and indium segregation for increasing indium concentration.     

HIGH-RESOLUTION SEQUENCE STRATIGRAPHIC ANALYSIS OF THE PERMIAN IN THE WESTERN SHANDONG AND HUAINAN-HUAIBEI COALFIELDS

The sedimentary characteristics and their combination succession of the Permian in the Shandong and Huainan-Huaibei coalfields are analyzed. The mid- and short-term stratigraphic base-level cycles are identified. High-resolution sequences are divided based on the above results. The study shows that the stratigraphic base-level cyclic method is an efficient way in the determination of the high-resolution sequences, especially in the classification of the terrestrial and transitional depositional succession.     

小型冲击叠加震源及应用效果

高分辨率地震勘探中，如何激发高频信号是至关重要的问题。当遇到地表松散的地层，且地下水位较低时，无论是锤击震源还是炸药震源，都显得一筹莫展。石油地震勘探使用的可控震源可以激发高频信号，并具有较强的抗干扰能力，已在国内外广泛使用。依据可控震源的基本原理，使用小功率电锤进行冲击叠加，在表层松软和有环境干扰的地区，获得了主频80～150 Hz的有效波信号，探测深度达到300 m，可以满足浅层高分辨地震勘探的需求。通过应用实例证明了方法的有效性和优越性。     

东濮凹陷文南油田文138断块沙二段下亚段层序地层

运用基准面旋回原理，通过岩心、录井、测井和地震资料的综合分析，在东濮凹陷文南油田文138井沙二段下亚段中识别出3种基本结构类型和7个亚类型的短期基准面旋回层序。其中，向上“变深”的非对称型主要发育在距物源区较近或物源供给较充分的三角洲前缘中的分流水道、河道间湾沉积区；向上“变浅”的非对称型发育在距物源供给区相对较远但供给量逐渐增多的三角洲前缘中的河口坝、远砂坝沉积区；向上“变深”复“变浅”的对称型往往发育于沉积速率始终小于可容纳空间增长率的三角州前缘区。研究结果表明，文138井沙二段下亚段发育中期基准面旋回（4级）14个，短期旋回（5级）40个，超短期旋回（6级）92个；单个中期基准面旋回的厚度一般为18～32m，单个超短期旋回的厚度平均为4m。     

一种利用目标雷达高分辨距离像幅度起伏特性的特征提取新方法

为了松弛高分辨距离像(HRRP)的方位敏感性,传统的雷达HRRP目标识别方法大都采用目标在一定方位角域内的平均像作为方位模板.实际上,距离像的幅度起伏特性也包含了一定的目标特征信息.本文基于散射点模型理论,提出了一种利用距离像幅度起伏特性的特征提取新方法.新方法提取的加权距离像特征反映了各个距离单元内目标散射点的分布情况,可以更好地描述目标散射特性.基于外场实测数据的识别实验结果表明,新的特征提取方法可以大幅度地提高识别性能.