螺旋线对斜拉索涡激振动特性影响的试验研究

为研究不同参数的螺旋线对斜拉索涡激振动特性和气动力的影响规律,进行了针对表面无螺旋线斜拉索和缠绕不同参数螺旋线斜拉索的节段模型风洞试验,螺旋线参数包括根数、直径和缠绕间距. 结果表明：斜拉索表面缠绕1根螺旋线的涡激振动振幅远大于2根或3根螺旋线;在亚临界雷诺数区,缠绕螺旋线斜拉索的平均气动阻力系数均小于无螺旋线斜拉索,最多可减小10.9%;缠绕2根螺旋线的斜拉索平均阻力系数整体比3根螺旋线小. 斜拉索表面缠绕间距s=8D（D为斜拉索直径）的2根螺旋线时,缠绕直径d<15 mm螺旋线的斜拉索涡激振动现象明显;d ≥15 mm的螺旋线可显著降低斜拉索涡激振动响应幅值,其脉动升力系数相较于无螺旋线斜拉索有明显降低,证明缠绕大直径螺旋线对涡激振动响应控制的有效性. 螺旋线的缠绕间距对斜拉索涡激振动的影响与螺旋线直径有关,当螺旋线直径较小时,缠绕间距对涡激振动的影响并不明显;当螺旋线直径较大时,间距的大小直接影响涡激振动的抑制效果.     

A new theory of rock-explosive matching based on the reasonable control of crushed zone

Rational rock-explosive matching is of great importance to enhancing explosive energy effective utili- zation and improving rock fragmentation effect. The traditionally emphasized method of acoustic impedance matching is not rational. Based on blasting breakage mechanism, a new theory of rock-explosive matching in drilling and blasting is proposed. The new approach chooses explosive parameters by reasonable control of the size of crushed zone under the condition of fully fragmentation between adjacent blast holes. This method can directly reflect the blasting fragmentation effect and energy effective utilization, which is easy to implement. Al- so, a modified model is developed, taken adjacent blast hole blasting loading into account. As a result, explo- sive parameters of different grades of rock are given in full coupling on-site mixed explosive charge for different project objectives.     

Genetic diversity revealed by genomic SSR and EST-SSR markers among common wheat, spelt and compectum

In this study, two SSR molecular markers, named genomic-SSR and EST-SSR, are used to measure the genetic diversity among three hexaploid wheat populations, which include 28 common wheat ( Triticum aestivum L. ), 13 spelt ( Triticum spelta L. ),and 11 compactum ( Triticum compactum Host. ). The results show that common wheat has the highest genetic polymorphism, followed by spelt and then compactum. The mean genetic distance between the populations is higher than that within a population, and similar tendency is detected for individual genomes A, B and D. Therefore, spelt and compactum can be used as potential germplasms for wheat breeding, especially for enriching the genetic variation in genome D. As compared with spelt, the genetic diversity between common wheat and compactum is much smaller, indicating a closer consanguine relationship between these two species. Although the polymorphism revealed by EST-SSR is lower than that by genomic-SSR, it can effectively differentiate diverse genotypes as well. Together with our present results, it is concluded that EST-SSR marker is an ideal marker for assessing the genetic diversity in wheat. Meanwhile, the origin and evolution of hexaploid wheat is also analyzed and discussed.     

Solid-liquid solvent extraction of metal ions

An overview of extraction of some trace metal ions using molten solvent (low melting substance) during last two decades is presented. The development of this technique since its inception is briefly traced. The comparison of extraction efficiency, thermo-dynamics and kinetics mainly involving extraction of rare earth ions between molten solvent extraction at high temperature and usual liquid-liquid extraction at room temperature are discussed in detail. The various parameters obtained from the previous and presentstudies such as equilibrium extraction constant K_ex, pH_1/2, the rmodynamic and kinetic data are displayed in tabular form. Finally, thecurrent demands, disadvantages and future prospects are also evaluated.     

Denoising of hyperspectral imagery by cubic smoothing spline in the wavelet domain

The acquired hyperspectral images （HSIs） are inherently attected by noise wlm Dano-varylng level, which cannot be removed easily by current approaches. In this study, a new denoising method is proposed for removing such kind of noise by smoothing spectral signals in the transformed multi- scale domain. Specifically, the proposed method includes three procedures： 1 ） applying a discrete wavelet transform （DWT） to each band; 2） performing cubic spline smoothing on each noisy coeffi- cient vector along the spectral axis; 3 ） reconstructing each band by an inverse DWT. In order to adapt to the band-varying noise statistics of HSIs, the noise covariance is estimated to control the smoothing degree at different spectra｜ positions. Generalized cross validation （GCV） is employed to choose the smoothing parameter during the optimization. The experimental results on simulated and real HSIs demonstrate that the proposed method can be well adapted to band-varying noise statistics of noisy HSIs and also can well preserve the spectral and spatial features.     

Snub-nosed monkeys (Rhinopithecus spp.): conservation challenges in the face of environmental uncertainty

The genus of snub-nosed monkey comprises five species that are only distributed in very limited areas in China,Vietnam and Myanmar.Tokin snub-nosed monkey(Rhinopithecus avunculus)is endemic to northern Viet-     

Contour representation based on wedgelet

1 .INTRODUCTIONRecently ,visual data has acquired a predominantrole in the exchange of information in many fieldsof communications . However , because of the in-convenience in the storage and distribution of thelarge amount of data ,i mage compression begins toplay ani mportant role . Althoughit has emerged asone of the preeminent tool for i mage compressionat present ,yet wavelets[1]still have obvious short-ages .In general ,a natural i mage contains edges ,smooth regions andtextures[2].…     

用铁泥制氧化铁红的研究

研究了以染化厂产生的废料铁泥为原料,采用焙烧法生产氧化铁红颜料的工艺,简要介绍了该法生产氧化铁红的反应机理及温度、酸度、焙烧时间对产品质量的影响。