妙用示性函数 巧解概率问题

通过构造示性函数,利用示性函数与概率的关系对Chebyshev不等式、期望等几个问题给出新的证明方法.     

应用推广的比较法得到的概率估计的几个结果

我们推广了比较法, 提出一个新方法得到 概率$\pr(X\leq t)$的可达的半参数界, 这里$X\in[0,M]$有给定的\, $\ep X=m_1$和$\ep X^2=m_2$. 我们的证明是初等的.     

SYNCHRONOUS EFFECT OF SLIPPING HEAVY LOADS ON RO-RO SHIP ROLLING IN WAVES

Common effect of wave and slip of internal vehicles will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibody system with a floating base is composed of ro-ro ship and slipping vehicles. Takes the rolling angle of the ship and the transverse displacements of the slipping vehicles on desk as freedoms. Making use of the analysis of apparent gravitation and apparent buoyancy, the wave rolling moment is derived. By means of dynamic method of multibody system, dynamic equations of the system are established. Taking a certain channel ferry as an example, a set of numerical calculation have been carried out for rolling response of the multibody system with a floating base of a ro-ro ship and displacements response of the slipping vehicles under common effect of free slipping vehicles and wave, and a conclusion has been drawn that the motion of the numerous free slipping heavy loads will trend to be synchronous under restraining of the side-wall bulkhead with time because of repeated collision.     

125 μm fiber based all-optical ultrasound probes for pulse-echo imaging

All-optical ultrasound probes that contain a photoacoustically-based ultrasound generator paired with a photonic acoustic sensor provide a promising imaging modality for diagnostic and MRI-compatible applications.Here, we demonstrate the fabrication of a fiber-based all-optical ultrasound probe and its applications in pulseecho ultrasound imaging. The ultrasound generator is fabricated on a 125 μm multimode optical fiber by forming a light-absorbing multiwalled carbon nanotube(MWCNT)-polydimethylsiloxane(PDMS) composite coating on its distal end. A peak-to-peak acoustic pressure of 0.95 MPa was achieved with laser irradiation at 2.46 μJ by chemically functionalizing the fiber surface to enable a strong adsorption. Ultrasound reception was performed by a fiber-laser ultrasound sensor that translates ultrasound pressure into differential lasing-frequency changes.By linearly scanning the probe, ex vivo two-and three-dimensional imaging of a segment of swine trachea was demonstrated by detecting the echo ultrasound signals and reconstructing the acoustic scatterers.The probe presents axial and lateral resolutions at 150 and 62 μm, respectively. The small-sized, side-looking all-fiber ultrasound probe presents a promising approach for assembling an interventional endoscopy.     

一个方差公式的多种证明

运用方差性质,协方差定义,函数凸性等方法,给出一个方差公式Var max(a,X)≤Var X的多种证明.     

DtBPF.2HBF4在合成新型含菲类OLEDs中的应用

合成了一种在空气中稳定的1,1"-双(二叔丁基膦)二茂铁双四氟硼酸盐,并应用于Pd₂(dba)₃/ DtBPF.2HBF₄催化的C-N偶联反应中以88 ~ 91 %产率合成系列新型的含菲类化合物,通过紫外吸收、荧光发射测试热重分析测试表明这些含菲类化合物拥有适合的紫外吸收、荧光发射、较大的摩尔吸光系数以及较窄的光学带隙,并且热稳定性好,玻璃化温度高,在有机蓝光电致发光材料中有潜在应用价值。     

双(二环己基膦基)烷烃双(四氟硼酸盐)的合成

以溴代环己烷和亚磷酸二乙酯为原料制得二环己基氧化膦(2),用四氢铝锂还原得二环己基膦氢,经锂化后依次与二氯烷烃和四氟硼酸反应合成了对空气稳定的1,3-双（二环己基膦基）丙烷双（四氟硼酸盐）(4a)和1,4-双（二环己基膦基）丁烷双（四氟硼酸盐）(4b),收率分别为62%和65%,其结构经¹H NMR, ¹³C NMR, ³¹P NMR和元素分析表征。并对关键反应条件进行了优化。     

滚装船-滑动车辆浮基多体系统的横摇研究

波浪和内部滑动车辆共同作用,使滚装船的横摇加剧。这是许多滚装船发生倾覆的重要原因之一。本文对由滚装船和滑动车辆组成的浮基多体系统中,取滚装船的横摇角和车辆在甲板上的横向位移为此系统的两个自由度。考虑非线性恢复力矩和非线性阻尼力矩的影响,运用浮基多体系统动力学方法,建立了系统的动力学方程。以某型海峡滚装渡轮为例,对在若干车辆同步滑动和波浪共同作用下的滚装船非线性横摇响应和车辆位移响应进行了数值计算,并与线性响应进行了比较,得出了考虑非线性时横摇角显著偏大的结论。     

滚装船在波浪中横摇时船上滑动重载荷的同步效应

由于波浪和内部滑动车辆共同作用,使滚装船的横摇加剧,这是许多滚装船发生倾覆的重要原因之一．对由滚装船和多辆滑动车辆组成的浮基多体系统,取滚装船的横摇角和多辆自由滑动车辆在甲板上的横向位移为此系统的自由度,通过对船舶在波浪中所受表观重力和表观浮力的分析,导出波浪作用力矩,运用多体系统动力学方法,建立了系统的动力学方程．以某型海峡滚装渡轮为例,对在多辆车自由滑动和波浪共同作用下的滚装船浮基多体系统的横摇响应和车辆位移响应进行了数值计算,得出了多个自由滑动的重载荷因相互碰撞在舷侧舱壁的约束下随着时间的延长其运动将趋于同步的结论．