Experimental and Theoretical Study on the Self-Weight Penetration Velocity of Suction Anchor Foundations in Sand

The application of the wellhead suction anchor in the second production test of natural gas hydrates(NGHs)in the South China Sea(SCS)was met with success.This design incorporates a central conductor guide pipe,which distinguishes it from traditional suction foundations.However,this addition resulted in a relatively high penetration resistance and a shallower penetration depth at the self-weight penetration stage.To mitigate this issue,the current study proposes an optimized design where the end of the suction foundation is sharpened.The installation characteristics of the traditional suction foundation and new suction foundation during self-weight penetration into sand are studied through laboratory tests and theoretical analysis.The flat and sharpened bottom shapes are considered in the traditional and new suction models.The effects of the initial penetration velocity on the initial penetration depth and soil plug and impact cavity characteristics are systematically studied.The results show that the self-weight penetration depth of the foundation with a sharpened bottom is 44.5%deeper than that of the foundation with a flat bottom.There are cavities around the foundation at the self-weight penetration stage,and the penetration depth is overestimated by 15%-30%.Finally,a model for predicting the penetration depth of the new suction foundation is proposed.

Comb-Based Filter Design Using Sharpening Technique and Certain Palindromic Polynomial

This paper presents a novel approach to improve aliasing rejection in comb-based decimation filters. The method is established on certain palindromic polynomials with all zeros on the unit circle and the sharpening technique. As a result, aliasing rejection and the passband characteristic are improved. The method is illustrated with various examples and compared with the methods from the literature. .

基于QCamera类的摄像头QT应用程序开发与后端图像处理

QT是一种跨平台开发环境,可以开发windows、android下的各种应用程序,所以深受程序员喜爱。现在笔记本、手机基本上都自带摄像头,所以开发摄像头应用程序也成了十分热门的一个方向。QT内部自带一个QCamera类使得它的摄像头应用程序开发变得非常简单。主要从摄像头的信息获取、摄像头的选择、摄像头的打开、摄像头图像回显、摄像头资源的关闭退出等几个方面介绍QT中的摄像头应用程序开发,并对获得的图像信息做了一些简单的锐化处理,使得结果易于让计算机进行对比分析,讨论了锐化处理中遇到的一些问题。

基于SPOT6影像的玛旁雍错湖泊面积变化研究

针对高原湖泊面积监测问题,采用2017年4月和2018年4月的SPOT6遥感影像,结合DEM数据,首先对数据进行图像镶嵌、正射校正和Gram-Schmidt Pan Sharpening算法融合等处理;再利用归一化差异水体指数提取湖泊整体;然后通过高斯低通滤波器突出水体特征,结合目视解译,选取合适的阈值精确划分水体边界;最后统计得到玛旁雍错湖泊的面积。结果表明,截至2018年4月,玛旁雍错湖泊总面积由412万km2减少到411.4万km2,平均退缩率为0.1%。通过分析普兰气象站的气象数据发现,玛旁雍错湖泊的萎缩与当年降水量变化和气温变化有关,降水量减少、气温升高导致湖泊萎缩,说明气象变化对玛旁雍错湖泊面积变化具有一定的影响。

Optimized analysis of sharpening characteristics of a compact RF pulse source based on a gyro-magnetic nonlinear transmission line for ultrawideband electromagnetic pulse application

We constructed a compact high-power RF pulse generator based on a gyro-magnetic nonlinear transmission line(GNLTL) to produce a high-voltage pulse with a sub-nanosecond rise time and a relatively high repetition rate, which shows great potential for application in the high-power ultrawideband electromagnetic effect, etc. The influence of incident pulse parameters(rise time and voltage amplitude) and line length on the sharpening characteristics of the GNLTL were investigated experimentally to optimize the rising rate of the modulated pulse front. Based on the GNLTL equivalent circuit model consisting of an LC ladder network, the rise time, the voltage conversion coefficient and the rising rate properties of a modulated pulse were also numerically analyzed in a wider range. The results show that a?>?90 k V RF pulse with a rise time of 350 ps and a repetition rate of 1 kHz in burst mode is produced by the GNLTL at an axial biasing magnetic field of 22 kA m^-1 and a line length of 30 cm under the condition of a 70 kV incident pulse. Applying a faster and higher incident pulse is conducive to improving the sharpening effect of the GNLTL. Furthermore, within a certain range, increasing the line length of the GNLTL not only reduces the rise time, but increases the voltage conversion coefficient and the rising rate of a modulated pulse. Furthermore, considering the energy loss of ferrite rings, there is an optimal line length to obtain the fastest rising rate of a modulated pulse front edge.

WorldView-2遥感影像融合方法实验研究

针对一景WorldView-2全色影像和多光谱影像,分别利用基于高通滤波的融合算法、IHS变换融合算法、PCA变换融合算法、小波变换融合算法和ENVI Pan Sharpening融合算法进行影像融合,并利用定量评价指标进行定量化评价。试验表明,Pan Sharpening算法最为理想。

The Application of the Edge Sharpening Operator to the Breast Near-Infrared Imaging

The principles of Gradient operator, Laplacian operator, LOG operator and Sobel operator are discussed. Certain features of breast can be extracted in different degrees and aspects from original images by applying four edge sharpening operators to the breast near-infrared imaging. A great number of cases prove that compared with the other three operators, the improved Sobel operator can effectively extract the structural features of the breast from an original image. It can be concluded that the improved Sobel operator can assist in diagnosing breast diseases.

DBS imaging based on Keystone transform

To correct the range walk through resolution cell in Doppler beam sharpening （DBS） imaging, a new DBS imaging algorithm based on Keystone transform is proposed. Without the exact values of the movement parameters and the look angle of the radar platform in the multi-targets environment, a linear trans- form on the received data is employed to correct different range walk values accurately under the condition of Doppler frequency ambiguity in this algorithm. This method can realize the cohe- rent integration in azimuth dimension and improve the azimuth resolution. In order to reduce the computational burden, a fast implementation of Keystone transform is used. Theoretical anal- ysis and simulation results demonstrate the effectiveness of the new algorithm. And through comparing the computational load of the fast implementation with several other algorithms, the real-time processing ability of the proposed algorithm is superior to that of other algorithms.

一种高效数字上变频器及其FPGA实现

数字上变频是软件无线电的关键技术之一。文章首先介绍了数字上变频器的基本原理和组成结构,并对其核心部件之一的CIC滤波器进行了改进,提出了一种能实现任意整数倍内插的高效完全非递归结构,并在ModelSim下进行了仿真。最后,在QuartusII下对使用该结构Sharpened CIC滤波器的数字上变频器系统进行了综合与仿真。

WorldView Ⅱ全色与多光谱影像融合算法的比较研究

遥感影像融合是基于某种算法,将全色与多光谱影像的优势进行有效结合,从而获得比单一数据更精确、更丰富的信息,有助于影像的特征信息提取和分类处理。WorldView II(简称WV2)影像是目前主流的高分辨率卫星,探讨WV2数据的实用融合方法对进一步推动影像深度应用具有重要意义。现结合WV2数据特点,从主观定性与客观定量两个方面对不同融合方法进行了评价。结果表明Pan Sharpening算法具有更强的适应性。

A novel enhancement method for low illumination images based on microarray camera

It is difficult but important to get clear information from the low illumination images. In recent years the research of the low illumination image enhancement has become a hot topic in image processing and computer vision. The Retinex algorithm is one of the most popular methods in the field and uniform illumination is necessary to enhance low illumination image quality by using this algorithm. However, for the different areas of an image with contrast brightness differences, the illumination image is not smooth and causes halo artifacts so that it cannot retain the detail information of the original images. To solve the problem, we generalize the multi-scale Retinex algorithm and propose a new enhancement method for the low illumination images based on the microarray camera. The proposed method can well make up for the deficiency of imbalanced illumination and significantly inhibit the halo artifacts as well. Experimental results show that the proposed method can get better image enhancement effect compared to the multi-scale Retinex algorithm of a single image enhancement. Advantages of the method also include that it can significantly inhibit the halo artifacts and thus retain the details of the original images, it can improve the brightness and contrast of the image as well. The newly developed method in this paper has application potential to the images captured by pad and cell phone in the low illumination environment.

Adaptive Multi-modal Fusion Instance Segmentation for CAEVs in Complex Conditions:Dataset,Framework and Verifications

Current works of environmental perception for connected autonomous electrified vehicles(CAEVs)mainly focus on the object detection task in good weather and illumination conditions,they often perform poorly in adverse scenarios and have a vague scene parsing ability.This paper aims to develop an end-to-end sharpening mixture of experts(SMoE)fusion framework to improve the robustness and accuracy of the perception systems for CAEVs in complex illumination and weather conditions.Three original contributions make our work distinctive from the existing relevant literature.The Complex KITTI dataset is introduced which consists of 7481 pairs of modified KITTI RGB images and the generated LiDAR dense depth maps,and this dataset is fine annotated in instance-level with the proposed semi-automatic annotation method.The SMoE fusion approach is devised to adaptively learn the robust kernels from complementary modalities.Comprehensive comparative experiments are implemented,and the results show that the proposed SMoE framework yield significant improvements over the other fusion techniques in adverse environmental conditions.This research proposes a SMoE fusion framework to improve the scene parsing ability of the perception systems for CAEVs in adverse conditions.

THE EFFECT OF THE CBN WHEEL DRESSING AND THE GRAIN HEIGHT PROTRUDING FROM THE BOND ON THE GRINDING PERFORMANCE

CBN (Cubic Boron Nitride) is a highly efficient abrasive and has unique properties (highhardness, high thermal stability and high chemical inertia). As early as 1969 CBN Wheels had al-ready been made and showed excellent performance for grainding high speed steels and othermaterials hard to be ground. So far, however, CBN Wheels are still not popularly utilized in theindustry, the writer considers the main reason being the inadequate study for practical applica-tions and especially the suitable dressing technique. The dressing of resinoid CBN Wheels discussed in the paper, is different from that ofconventional ones. It has to be divided into two operations, truing and sharpening, each of whichhas its specific and independent functions. A simple dressing method with a lot of informationsuitable for production is studied; finally, the grain height protruding from the bond is taken asan index for evaluating the dressing results, and the effect of grain height on the grinding per-formance is discussed. By selecting proper conditions according to the workpiece requirements, abetter technical and economical benifit can be obtained.

Development of a High Power Programmable Precise Time-Delay Trigger/Ignition System for MFCG

High-power precise delay trigger/ignition system is a programmable pulse generator developed for experiment controlling in explosively driven magnetic flux compression generators. Precise delay pulses are generated by the digital circuit, after being magnified and sharpened through multistage isolated amplifiers and rising edge sharpening device, high-voltage steep delay pulses with precision less than μs level are obtained. This system has been used in our compact magnetic flux compression generator experiments in place of the traditional primaeord delay device.

SEVERAL PROBLEMS IN DESIGNING DBS SYSTEMS FOR AIRBORNE PULSE DOPPLER RADAR

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Contour reconstruction of three-dimensional spiral CT damage image

In order to improve the diagnosis and analysis ability of 3D spiral CT and to reconstruct the contour of 3D spiral CT damage image,a contour reconstruction method based on sharpening template enhancement for 3D spiral CT damage image is proposed.This method uses the active contour LasSO model to extract the contour feature of the 3D spiral CT damage image and enhances the information by sharpening the template en.hancement technique and makes the noise separation of the 3D spiral CT damage image.The spiral CT image was procesed with ENT,and the statistical shape model of 3D spiral CT damage image was established.The.gradient algorithm is used to decompose the feature to realize the analysis and reconstruction of the contour feature of the 3D spiral CT damage image,so as to improve the adaptive feature matching ability and the ability to locate the abnormal feature points.The simulation results show that in the 3D spiral CT damage image contour reconstruction,the proposed method performs well in the feature matching of the output pixels,shortens the contour reconstruction time by 20/ms,and provides a strong ability to express the image information.The normalized reconstruction error of CES is 30%,which improves the recognition ability of 3D spiral CT damage image,and increases the signal-to noise ratio of peak output by 40 dB over other methods.

Doppler Beam Sharpening for Arc Turning Flying

The signal processing and error analysis of arc turning flying for Doppler beam sharping (DBS) are described in the paper. As a sort of synthetic aperture radar, DBS is different from strip or spotlight mapping. The analytical expressions of DBS processing for both the inside arc turning and outside arc turning flying are given. The computer simulation of arc turning flying with an acceleration of 3g was performed on an IBM-PC. The results showed that the error of arc turning flying of DBS can be made negligibly small.

Discussion on Surface Roughness of Tobacco Cutter Roller Grinding

The cutting machine is an important tobacco equipment, in which the sharpening system is an important part of the cutting machine, which is mainly responsible for the real-time grinding of the blades on the cutter roller parts of the shredding machine. The quality of the blade grinding is directly related to the size of the cutting force, the cutting edge of tobacco shreds and the breaking rate, etc. Therefore, it is necessary to study the relationship between surface roughness and relevant parameters such as cutter roller speed, grinding wheel reciprocating speed, grinding wheel grinding radius and grinding wheel abrasive grain size.

Process planning and contour-based error compensation for precision grinding of miniature scalpels

Miniature scalpels are mainly used in microsurgeries such as ophthalmic and cardiovascular surgeries.The size of a miniature scalpel is only a few millimeters,and the precision of the blade shape is high,which makes production of miniature scalpels extremely difficult.This study proposes a new sharpening process for grinding miniature scalpels on a four-axis machine tool.A post-processing algorithm for a four-axis grinding machine based on a kinematics model is established.We then propose a corresponding parameter calibration method for the parameters used in the kinematics model.Because of possible errors in the parameter calibration,a contour-based error compensation method is proposed for accurate adjustments to the edge shape following grinding.This can solve the problem of large deviations between the actual edge shape after grinding and the ideal edge shape.The effectiveness of the proposed process planning and error compensation method is verified experimentally,and the grinding process parameters of the miniature scalpel are optimized to improve its surface processing quality.The sharpness of the optimized miniature scalpel is less than 0.75 N,and the blade shape is symmetrical,which meets the technical requirements of miniature scalpels.