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击顶制导  [PDF]
兵工学报 , 1992,
Abstract: ?论述了反坦克导弹精确制导发展的一个重要问题:击顶制导。给出了准三点导引法和适用于遥控反坦克导弹的掠飞击顶制导律;准比例导引法和适用于自寻的反坦克导弹的俯冲击顶制导律;以及实现上述两种击顶制导律的三通道参数最优击顶数字控制器。
Minimizing Seam Artifacts in Image Stitching
C.V. Veena
Asian Journal of Information Technology , 2012,
Abstract: A specialized form of image mosaicing known as image stitching has become increasingly common, especially in the making of panoramic images. The stitching quality is measured visually by the similarity of the stitched image to each of the input images and by the visibility of the seam between the stitched images. In order to define and get the best possible stitching, first of all noise is removed from the input images which is done as a preprocessing step and also there are several formal cost functions for the evaluation of the stitching quality. In these cost functions the similarity to the input images and the visibility of the seam are defined in the gradient domain, minimizing the disturbing edges along the seam. A good image stitching will overcome both photometric inconsistencies and geometric misalignments between the stitched images. This approach is demonstrated in various applications including generation of panoramic images, object insertion and stitching of object parts.
An Analysis Of Hybrid Techniques Of Seam Carving
Ms. K. Thilagam,,Dr. S. Karthikeyan
International Journal on Computer Science and Engineering , 2011,
Abstract: Diversified display devices and advancement in image processing techniques have increased the need for content aware resizing of images to fit into display devices of varying resolutions. Traditionalresizing methods scaling, cropping, warping are all content unaware methods. Seam Carving has gained popularity in this scenario but it is not without any setbacks. Instead of searching for a single best operator a combination of multiple operators are proposed to benefit from each of these techniques. In this paper we survey such techniques combined with seam carving, which we term Hybrid techniques. We also analyze their efficiencies based on parameters such as content preservation, global visual impacts and computational complexities.
简单管路中水击的类型偏误分析及解析计算
Effect of errors in predicting the water hammer types and pressures in a simple pipeline
 [PDF]

张明,郑双凌,马吉明,齐文彪
- , 2017, DOI: 10.16511/j.cnki.qhdxxb.2017.26.052
Abstract: 简单管路的水击分析是水电站设计的重要部分。该文对目前设计中采用的阀门开度匀速变化时水击的解析计算中存在的问题进行研究,详细推导和分析水击计算的区域划分,给出了正确的负水击区域划分图;通过以直线代替曲线的方式,提出足够精确的简化水击区域划分图;通过与精确水击区域划分图的比较,阐明了简化水击计算中可能出现的类型误判;基于直接求取水击最大值的考虑,提出第一相水击和末相水击类型的后验判别方法。此外,还给出了直接水击和第一相水击的直接计算公式。算例分析表明:该文给出的水击区域划分、提出的水击类型后验判别方法以及推导的水击直接计算公式正确可行。
Abstract:The analysis of water hammer in a simple pipeline is a fundamental problem in hydropower station designs. The type and evaluation of maximum water hammer in simple pipeline during the uniform closure or opening of a hydraulic turbine is studied. In particular, the type prediction is rectified for negative water hammer. The accurate simplified models for the prediction of positive and negative indirect water hammers are proposed to replace curves in the indirect water hammer domains with straight lines. With these models, possible errors due to inaccurate predictions of the water hammer in the simplified water hammer evaluation model currently adopted in the hydroelectric engineering are illustrated comparatively. A method is given for directly determining the maximum indirect water hammer pressure, no longer needing the prior prediction of first-phase or end-phase water hammer. In addition, formulas are given for the indirect water hammer without solving all the equations. The validity and applicability of the water hammer prediction and evaluation, including the method and formulas for indirect water hammer, are verified by examples.
A quality problem in seam welds in aluminum extrusion  [PDF]
S. Bingo,M.S. Keskin
Archives of Materials Science and Engineering , 2007,
Abstract: Purpose: Seam welds occur during the hollow profile extrusion; the billet’s material is divided into separate metal streams by the bridges of the die which support a mandrel, and then these metal streams are welded in welding chamber behind the bridges. When the desired conditions have not been provided, the required quality in seam welds may not occur. One of the possible reasons for this situation is a poor metal feed. In this study, an insufficient pressure problem occurring in seam welds on an aluminum extrusion profile section is investigated.Design/methodology/approach: The study was realized on a hollow extrusion profile type which has seam weld zones. The experimental profile was produced by a real extrusion press which has a capacity of 1460 tones.Findings: The poor metal feed occurring on specimen is shown by microstructural pictures. Microstructure of the main region has a homogenous appearance. In the microstructure, containing seam weld region, only a slight change was observed in seam weld region. However, there was no significant change in near of seam weld regions. This points out that there has been no metallurgical problem. Therefore, the problem is an insufficient pressure problem and this caused poor metal feeding. In the other hand, micro hardness tests are realized on seam weld region, main region and defective region’s surround of specimen’s section. After the micro hardness tests important differences are shown among these regions’ strength. Hardness values of seam weld region were lower than the main material’s hardness values, but higher than the defective region’s.Practical implications: In application, seam welds occur on hollow profiles produced by aluminum extrusion.Originality/value: As a result, this study shows a quality problem in seam welds in aluminum extrusion.
Geochemistry and mineralization of Novaky coal seam
Verbich Franti?ek
Acta Montanistica Slovaca , 1998,
Abstract: The mineralization and geochemistry of the most important Slovak coal deposit in Novaky was intensively studied in the past. The favourable geological conditions create rich mineral association. There are different minerals in the deposit and they are responsible for the enhanced content of some elements in the coal. The summary of notions about geochemistry and mineralization of the coal seam with the emphasis on the main harmful elements sulphur and arsenic and their spacial distribution are studied in this paper.
Using roofs of a seam resonance system to create the model of bump phenomenom - a coal seam in the OKR conditions
Bukovansky Stanislav
Acta Montanistica Slovaca , 1999,
Abstract: Like an ideal model of the bumps rise is possible to create for the OKR saddle layers seams conditions on the base of analyses of oscillation effects resp. drifts using roofs of a seam resonance system - a coal seam at the mountain massif.
直接水击公式研究  [PDF]
马跃先,周琼,李世英,吴昊
人民黄河 , 2007,
Abstract: ?对joukowsky水击公式推导过程进行了分析,认为其推导过程中忽略了不该忽略的二阶微量.以动量定理为基础建立微分方程,考虑水体可压缩性和管壁弹性,得到不同于joukowsky水击公式的直接水击公式,与相关研究文献进行比较后认为,所建公式比joukowsky公式更合理.
Relative Performance of Lockstitch and Chainstitch at the Seat Seam of Military Trouser  [PDF]
Arunangshu Mukhopadhyay, Ph.D.
Journal of Engineered Fibers and Fabrics , 2008,
Abstract: An experimental investigation of the effect of two different type of stitches viz., lockstitch and chainstitch at the seat seam of trouser for military armed forces has been reported. Performance of chainstitched seam is found to be much better as regards lower value of force at low level of strain, higher value of force at break, strain at break and work of rapture. In general with the change in thread linear density, greater improvement in seam strength, seam strain at break and work up to fracture are obtained in case of chainstitched seam. On laundering, in general force at small strain and force at break increases, the change being more in case of lockstitched fabric. However, strain at break decrease marginally on laundering in case of both the stitches.
Properties of seam welds produced with different extrusion parameters  [PDF]
S. Bingol,M.S. Keskin,A. Bozacl
Archives of Materials Science and Engineering , 2007,
Abstract: Purpose: This study focuses to investigate the effects of different extrusion parameters on microstructural properties of seam (longitudinal) welds in aluminum extrusion profiles.Design/methodology/approach: To realize the study, it is studied on a hollow extrusion profile type which has seam weld zones. The experimental profile was produced in different temperatures, billet temperatures and ram speeds by a real extrusion press which has a capacity of 1460 tones. These parameters are some of the most important parameters in an extrusion process.Findings: Some structural differences are occurred between having the different extrusion parameters both seam welds and without weld regions, when the experimental results are observed. In addition, it was observed commonly the structure of the material had a change through re-crystallization with increasing temperatures. This situation decreases the significance of seam weld lines. Moreover, the grain size is getting smaller with increasing ram speed as it is shown in microstructural figures.Research limitations/implications: Also some structural differences in seam welds may occur for having the other extrusion parameters without temperature and speed. But, the other extrusion parameters are not used in this study. Therefore, effect of some other important parameters such as pressure, extrusion ratio can be investigated in future.Practical implications: In application, seam welds occur on hollow profiles. This study demonstrates that some extrusion parameters effect to microstructure of seam welds.Originality/value: It is shown that different microstructural properties take place due to the process parameters variations and natural of extrusion method in the extrusion production. They cause also variations on structural features.
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