Hydroelastic Response of A Circular Plate in Waves on A Two-Layer Fluid of Finite Depth

The hydroelastic response of a circular, very large floating structure(VLFS), idealized as a floating circular elastic thin plate, is investigated for the case of time-harmonic incident waves of the surface and interfacial wave modes, of a given wave frequency, on a two-layer fluid of finite and constant depth. In linear potential-flow theory, with the aid of angular eigenfunction expansions, the diffraction potentials can be expressed by the Bessel functions. A system of simultaneous equations is derived by matching the velocity and the pressure between the open-water and the platecovered regions, while incorporating the edge conditions of the plate. Then the complex nested series are simplified by utilizing the orthogonality of the vertical eigenfunctions in the open-water region. Numerical computations are presented to investigate the effects of different physical quantities, such as the thickness of the plate, Young’s modulus, the ratios of the densities and of the layer depths, on the dispersion relations of the flexural-gravity waves for the two-layer fluid. Rapid convergence of the method is observed, but is slower at higher wave frequency. At high frequency, it is found that there is some energy transferred from the interfacial mode to the surface mode.

Analysis of Second-Harmonic Generation of Low-Frequency Dilatational Lamb Waves in a Two-Layered Composite Plate

We analyze the effect of second-harmonic generation（SHG） of primary Lamb wave propagation in a two-layered composite plate, and then investigate the influence of interfacial properties on the said effect at low frequency. It is found that changes in the interfacial properties essentially affect the dispersion relation and then the maximum cumulative distance of the double-frequency Lamb wave generated. This will remarkably influence the efficiency of SHG. To overcome the complications arising from the inherent dispersion and multimode natures in analyzing the SHG effect of Lamb waves, the present work focuses on the analysis of the SHG effect of low-frequency dilatational Lamb wave propagation. Both the numerical analysis and finite element simulation indicate that the SHG effect of low-frequency dilatational Lamb wave propagation is found to be much more sensitive to changes in the interfacial properties than primary Lamb waves. The potential of using the SHG effect of low-frequency dilatational Lamb waves to characterize a minor change in the interfacial properties is analyzed.

Temperature-Dependent Newtonian Rheology in Advection-Convection Geodynamical Model for Plate Spreading in Eastern Volcanic Zone, Iceland

Geodynamic process as advection-convection of the Mid-Atlantic Ocean Ridge (MAR), that is exposed on land in Iceland is investigated. Advection is considered for the plate spreading velocity. Geodetic GPS data during 2000-2010 is used to estimate plate spreading velocity along a profile in the Eastern Volcanic Zone (EVZ), Iceland striking N102。E, approximately parallel to the NUVEL-1A spreading direction between the Eurasian and North American plates. To predict subsurface mass flow patterns, temperature-dependent Newtonian rheology is considered in the finite-element models (FEM). All models are considered 2-D with steady-state, incompressible rheology whose viscosity depends on the subsurface temperature distribution. The thickness of lithosphere along the profile in the EVZ is identified by 700。C isotherm and 1022 Pa s iso-viscosity, those reach 50 ± 3 km depth at distance of 100 km from rift axis. Geodetic observation and model prediction results show the ~90% of spreading is accommodated within ~45 km of the rift axis in each direction. Model predicts ~8.5 mm.yr-1 subsidence at the surface of rift center when magmatic plumbing is inactive. The rift center (the highest magmatic influx is ~11 mm.yr-1) in model shifts ~10 - 20 km west to generate observed style surface deformation. The spreading velocity, isotherm and depth of isotherm are the driving forces resulting in the surface deformation. These three parameters have more or less equal weight. However, as the center of deformation in the EVZ shifts and most of the subsidence takes place in the volcanic system that is currently the active which is the located of plate axis.

Vibration of a Two-Layer“Metal+PZT”Plate Contacting with Viscous Fluid

The present work investigates the mechanically forced vibration of the hydro-elasto-piezoelectric system consisting of a two-layer plate“elastic+PZT”,a compressible viscous fluid,and a rigid wall.It is assumed that the PZT(piezoelectric)layer of the plate is in contact with the fluid and time-harmonic linear forces act on the free surface of the elastic-metallic layer.This study is valuable because it considers for the first time the mechanical vibration of the metal+piezoelectric bilayer plate in contact with a fluid.It is also the first time that the influence of the volumetric concentration of the constituents on the vibration of the hydro-elasto-piezoelectric system is studied.Another value of the present work is the use of the exact equations and relations of elasto-electrodynamics for elastic and piezoelectric materials to describe the motion of the plate layers within the framework of the piecewise homogeneous body model and the use of the linearized Navier-Stokes equations to describe the flow of the compressible viscous fluid.The plane-strain state in the plate and the plane flow in the fluid take place.For the solution of the corresponding boundary-value problem,the Fourier transform is used with respect to the spatial coordinate on the axis along the laying direction of the plate.The analytical expressions of the Fourier transform of all the sought values of each component of the system are determined.The origins of the searched values are determined numerically,after which numerical results on the stress on the fluid and plate interface planes are presented and discussed.These results are obtained for the case where PZT-2 is chosen as the piezoelectric material,steel and aluminum as the elastic metal materials,and Glycerin as the fluid.Analysis of these results allows conclusions to be drawn about the character of the problem parameters on the frequency response of the interfacial stress.In particular,it was found that after a certain value of the vibration frequency,the presence of the metal layer in the two-layer plate led to an increase in the absolute values of the above interfacial stress.

Modeling the spread of hot-rolled Ni-based alloy plates

The width spread of Ni-based alloy plates in the rolling process is studied. An equation for describing therolling spread of Ni-based alloy plate is proposed based on production data and the Bachtinow equation, which cannot fully account for the compositional variability of Ni-based alloys. To address this, a new coefficient for alloying is added to the equation based on production data. By adding alloying coefficients, it is possible to improve the prediction accuracy for the rolling spread of Ni-based alloy plates and thus better control the width of the rolling spread of different steel grades.

Structural characteristics of the KPR-CBR triple-junction inferred from gravity and magnetic interpretations,Philippine Sea Plate

The intersection of the Kyushu-Palau Ridge(KPR)and the Central Basin Rift(CBR)of the West Philippine Basin(WPB)is a relic of a trench-trench-rift(TTR)type triple-junction,which preserves some pivotal information on the cessation of the seafloor spreading of the WPB,the emplacement and disintegration of the proto-Izu-Bonin-Mariana(IBM)Arc,and the transition from initial rifting to steady-state spreading of the Parece Vela Basin(PVB).However,the structural characteristics of this triple-junction have not been thoroughly understood.In this paper,using the newly acquired multi-beam bathymetric,gravity,and magnetic data obtained by the Qingdao Institute of Marine Geology,China Geological Survey,the authors depict the topographic,gravity,and magnetic characteristics of the triple-junction and adjacent region.Calculations including the upward continuations and total horizontal derivatives of gravity anomaly are also performed to highlight the major structural features and discontinuities.Based on these works,the morphological and structural features and their formation mechanisms are analyzed.The results show that the last episode amagmatic extension along the CBR led to the formation of a deep rift valley,which extends eastward and incised the KPR.The morphological and structural fabrics of the KPR near and to the south of the triple-junction are consistent with those of the western PVB,manifesting as a series of NNE-SSW-and N-S-trending ridges and troughs,which were produced by the extensional faults associated with the initial rifting of the PVB.The superposition of the above two reasons induced the prominent discontinuity of the KPR in deep and shallow crustal structures between 15°N‒15°30′N and 13°30′N‒14°N.Combined with previous authors’results,we propose that the stress produced by the early spreading of the PVB transmitted westward and promoted the final stage amagmatic extension of the CBR.The eastward propagation of the CBR destroyed the KPR,of which the magmatism had decayed or ceased at that time.The destruction mechanism of the KPR associated with the rifting of the PVB varies along strike the KPR.Adjacent to the triple-junction,the KPR was destroyed mainly due to the oblique intersection of the PVB rifting center.Whereas south of the triple-junction,the KPR was destroyed by the E-W-directional extensional faulting on its whole width.

Width Compensation and Correction for the Plan View Pattern Control Function on Plate Mill

Research works on width compensation and correction were carried out in order to eliminate the effects of the PVPC （ plan view pattern control） on width accuracy of plate mill. The thickness correction calculation formula was derived for compensation the width deviation caused by PVPC function, and the formula is unified under the thinning and thickening conditions. In order to improve the width calculation accuracy, width spread calculation process was modified with dividing one large reduction pass to several small reduction calculation steps. The thickness wedge was simplified to rectangle based on the volume constant principle, and the width spread model for PVPC was constructed. The width compensation and correction for the PVPC functions are used for the online control process, and the Product dimension accuracy is improved. With the decrease of Crop losses, the Droduct yield was increased with 0. 2%.

基于高通量培养分析稻虾共作模式土壤的细菌群落

高通量测序技术的发展发现并鉴定了土壤微生物的未培养物种,然而,仅依赖非培养的高通量测序无法获得发挥关键功能的微生物培养物,限制了对其功能的验证及其应用,这对关键功能微生物的机理性研究和应用具有一定的局限性.本研究以稻虾共作和水稻单作两种稻作模式的土壤样品为研究对象,分别对比了传统平板涂布、96孔培养板划线分离以及将非培养和培养法相结合的———“96孔高通量培养法”3种方法的土壤细菌分类差异、菌群多样性、组成特异性以及细菌功能特征.结果表明,相对于传统涂布培养法,96孔高通量培养法所获取的细菌数量高约5倍,能鉴定到属的培养物高约4倍,预测功能鉴定提高约2倍.由此可见,“96孔高通量培养法”大大提高了对土壤细菌培养物的获取和鉴定率.本研究弥补了传统培养法的获得率低的不足,拓宽了高通量培养技术的应用领域,同时,也为进一步揭示稻虾共作模式参与土壤生态变化过程的微生物机制提供研究基础.

基于频率域点扩散函数的视频中运动模糊车牌复原与识别优化

车辆是刑事案件中常使用的工具,车牌识别是涉案车辆认定的重要依据之一,因此对运动模糊造成的车牌图像退化的复原是刑事技术工作的重要研究方向。文中提出一种基于频率域点扩散函数参数估计的车牌图像复原算法,运用二维离散傅里叶变换、Radon变换以及Wiener滤波算法解决监控视频视角下运动模糊车牌的复原问题。通过预处理对运动模糊图像进行灰度化和降噪,并对图像添加Hanning窗,进行二维离散傅里叶变换和对数运算,计算图像的功率频谱图,运用Radon变换对频谱图进行检测,估算模糊方向;对频谱图进行最小值计算,求模糊长度,完成对点扩散函数两个参数的估算。通过Wiener滤波算法进行图像反卷积,实现图像复原。针对传统频谱图估算模糊参数易受中央亮线干扰的问题,在离散傅里叶变换之前添加窗函数进行优化。使用道路监控拍摄的模糊图像,进行点扩散函数参数估计实验,同时与目前未加窗的方法进行对比,验证所提算法的复原效果。实验结果证明,所提算法在复原车牌图像语义信息方面具有优势,能为刑事图像技术领域模糊车牌复原提供方法补充。

大南海地区新生代板块构造活动

在新生代澳大利亚板块和欧亚板块之间的大洋中,存在一些地块(微板块);同时,澳大利亚板块北部边缘的一些地块先后和澳大利亚板块分离,向北运动,与一些和欧亚板块分离出来的地块先后发生碰撞缝合。在此期间,由于地块分离而发生海底扩张,产生许多小洋盆,如南海、苏录海、苏拉威西海、安达曼海等,最后形成了东南亚地区今日的构造景观。笔者从大南海地区新生代的构造演化史之框架来研究南海地区新生代的构造演化历史,认为南海地区新生代的构造活动既与印度板块和欧亚板块的碰撞有关,也与太平洋板块向欧亚板块的俯冲活动有联系;同时,还受到澳大利亚板块向北运动之影响。南海地区在新生代发生过两次海底扩张,第一次海底扩张发生在42～35Ma前,是受印度板块和欧亚板块碰撞而引起欧亚大陆之下向东南方向之地幔流的影响而发生的,其海底扩张方向为NW-SE,产生了南海西南海盆;第二次海底扩张发生于32～17Ma前。由于太平洋板块向欧亚板块俯冲,俯冲的大洋岩石圈已达700km深处,阻挡了欧亚大陆的上地幔向东南方向之流动,从而转向南流动,引起南海地区南北向海底扩张,即新生代第二次海底扩张,产生了南海中央海盆。南海新生代洋盆诞生之后,由于大南海地区继续有地块碰撞和边缘海海底扩张,对南海南部地区产生挤压。

溶洞顶板极限承载力研究

针对国标《工程岩体分级标准》[1]中Ⅲ、Ⅳ类岩体条件,采用显式有限差分法,对岩溶地区扩大基础下椭球状溶洞顶板稳定性进行了分析。通过对溶洞顶板的应力和位移变化规律及塑性区演化规律研究,得出在两种岩体条件下不同溶洞跨度和顶板厚度时溶洞顶板的极限承载力,绘出了溶洞跨度、顶板厚度对极限承载力的联合影响曲面。溶洞顶板的极限承载力随溶洞跨度的增大而减小,随溶洞顶板厚度的增大而增大。在其他条件相同时,Ⅳ类岩体的溶洞顶板极限承载力仅为Ⅲ类岩体的1/3左右。

中国早震旦世构造-岩相古地理

早震旦世是中国各主要板块普遍发育海相沉积的开始,是目前被证实是最早的有效海相烃源岩的发育时期。该时期是中国各主要陆块处于新一轮洋盆扩张、板块离散、海水进侵旋回的初始期,总体的构造-沉积格局呈"多岛洋"。陆块的固结年龄、规模和稳定性在很大程度上控制着三大准地台及其周边的古地理面貌和岩相组合。华北准地台的基底固结年龄最早,规模最大,稳定性最好,因此在早震旦世以大面积古陆为主,在台地边缘以浅海滨岸相碎屑岩为主,浅水碳酸盐台地相和深水斜坡相不发育。塔里木准地台在早震旦世以海陆并存为特征,在塔北、塔中存在古陆剥蚀区,向外以浅海滨岸相碎屑岩和斜坡-盆地相混合沉积为特色。扬子准地台在康滇地区存在古陆,其余地区基本为海水所侵没,发育台地-斜坡-盆地的完整相序。这种构造-沉积格局具有长期的继承性影响,主要表现在:(1)在早古生代早期的洋盆扩张-海侵旋回,扬子和塔里木比华北更发育被动陆缘斜坡-盆地相烃源岩;(2)在早古生代晚期的洋盆关闭-海退旋回,华北最先经历海退,而扬子和塔里木仍在一定时间内保持海相沉积,甚至在准地台内部发育较深水烃源岩相。

涡流空气分级机内物料分布的模拟试验研究

为研究涡流空气分级机内物料分布的规律,探索物料在涡流空气分级机内的分散方法,文中设计了撒料盘试验来模拟涡流空气分级机内物料分布,并进行了物料分布的计算与试验研究。以建筑用标准砂做试验,结果表明:撒料盘转速的提高可以改善大颗粒物料的分散性,而对小颗粒物料的分散性影响较小;物料的粒度分布范围对物料分散性影响较大,粒度分布范围越宽,分散性越差,同时还研究了撒料盘结构对物料分散性的影响。结果表明:双层撒料盘的使用能将物料在承料面上的单位面积堆积量从单层撒料盘的0.067 g/cm2降低到0.042 g/cm2,相对减少量为37.31%,从而提高物料在分级机内的分散性。

快中子照相中的点扩展函数计算

快中子照相中,基于反冲核原理探测快中子的有机闪烁体平板是普遍采用的快中子辐射转换体。模拟了D-T中子垂直入射BC400闪烁体平板,计算了不同厚度平板闪烁体的点扩展函数,对14.1 MeV快中子照相中闪烁体固有分辨率随厚度的变化进行了研究。计算结果表明,在不考虑二次中子与闪烁体作用及背景噪声等情况时,点扩展函数几乎不依赖于闪烁体厚度。同时,计算还表明在一定的分辨率范围内,由于荧光收集效率的限制,闪烁体厚度增加并不会改善图像对比度。

涡流空气分级机撒料盘分散物料模拟实验研究

以建筑用标准砂为原料,设计撒料实验用以模拟物料在涡流空气分级机撒料盘上的分布,并研究撒料盘的转速对于颗粒速度及其运动轨迹的影响。结果表明:影响物料颗粒离开撒料盘速度的主要因素是颗粒与撒料盘间的摩擦力,颗粒越大,与撒料盘间的摩擦力越大,离开撒料盘的速度越大;撒料盘转速和撒料落点影响颗粒运动的方向。明确了撒料盘分散物料是因为粗、细颗粒与撒料盘间的摩擦力不同,造成了二者离开撒料盘的速度不同进而分离开来。提出了改善物料分散的措施,即加大颗粒与撒料盘间的摩擦力。

生物破乳剂产生菌的筛选及其方法研究

针对生物破乳剂产生菌筛选难的问题,采用显色法、溶血细胞测试法、表面张力测定法和排油圈法从6种不同菌源对生物破乳菌产生菌进行了筛选。通过试验筛选得到了17株生物破乳剂产生菌,其中24h内破乳率高于70%的破乳菌有5株;油田含油污泥、采油废水生物处理污泥和污水处理厂剩余污泥是筛选破乳菌的较好的菌源;显色法、溶血圈法存在检测范围的局限性;表面张力测定法和排油圈法是最为简易和准确的生物表面活性剂产生菌的筛选方法,采用模型乳状液对生物破乳剂产生菌进行筛选最为直接和准确,但工作量大、所需时间长,因此在筛选高效破乳菌时,建议采用表面张力、排油圈法进行初筛,而后通过模型乳状液破乳进行验证。

微通道板像增强器的调制传递函数的测量与研究

根据狭缝法测量调制传递函数(MTF)的理论,建立了微通道板(MCP)像增强器的MTF测量装置.利用CCD相机测量像增强器对狭缝的空间响应,得到系统的线扩散函数(LSF) ,经过傅里叶变换求出MTF.实验测量了两种MCP像增强器的MTF,得到的极限分辨率与厂家标定值一致.在不同的工作偏压下以及不同的像面位置处的MTF测量结果表明,像增强器的空间分辨能力随着光阴极偏压的升高逐渐提高并趋于稳定.随MCP偏压的升高而迅速下降,在一定的电压范围内不随荧光屏电压的变化而改变;像增强器在不同像面位置处的空间分辨能力变化较小.

单液滴撞击高温钢板表面铺展特性实验研究

对液滴撞击高温钢板表面铺展特性进行了实验研究。应用压电式共振腔均匀液滴发生器产生不同粒径不同速度的液滴,撞击400℃的高温不锈钢钢板表面,其中液滴工质为去离子水,撞击表面为2520不锈钢。用高速摄像机及IPP软件进行拍摄及图像处理。实验结果表明:相同韦伯数(We)下,液滴速度对铺展因素的影响大于液滴粒径,随着We增大液滴最大铺展因素增加。液滴撞击过程中We=39.3时液滴处于临界破碎状态。液滴撞击高温固体表面最大铺展因子大于撞击干燥常温固体表面。并且计算得出We与最大铺展因子的关系式。

用位相板实现景深延拓的原理与模拟实验研究

对波前编码技术实现景深延拓的原理进行了研究,分析了波前编码系统成像对离焦不敏感的原因,得到了波前编码光学系统景深延拓扩展率公式,发现了景深延拓扩展率与位相板参量的关系.利用Zemax设计了波前编码光学系统,用Matlab进行了成像模拟实验,实验结果表明,波前编码系统能提高传统光学系统的景深,提高的倍数由三次相位板的相位常量决定.

商州蛇绿岩带与晋宁运动

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