Dependence of high electric-field-induced strain on the composition and orientation of Pb(Mg1/3Nb2/3)O3-PbTiO3 crystals

Electric-field-induced strain behavior of (1−x)Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃ (PMNT) crystals with different orientations and compositions was investigated for use as electromechanical actuators. Crystallographically, high strains with low hysteresis were achieved for 〈001〉 oriented rhombohedral crystals (29%≤x≤31%) near a morphotropic phase boundary, rather than 〈110〉 and 〈111〉. Domain instability could explain inferior strain levels and large hysteresis for 〈110〉 and 〈111〉 oriented crystals. Ultrahigh strain levels up to 1.8% could be achieved for 〈001〉 oriented PMNT crystals, being related to an E-field induced phase transition. −2 kV/cm negative E-field can be applied to PMNT ferroelectric material with low hysteresis. High strain with low hysteresis makes PMNT crystals promising candidates for high performance solid-state actuators.     

基于网格的知识资源挖掘研究

为满足网络上不同用户群体对个性化资源的要求,文章从网格与服务网格的概念出发,引入知识挖掘技术,提出了网格环境下的个性化知识资源挖掘实现框架,并对其实现功能与应用加以分析.     

一种VSAT数据通信网络报文传输协议的分析

本文描述并分析了一种适用于多信道ＶＳＡＴ卫星数据通信网的报文传输协议，特别是考虑了无线信道误码率对传输协议的影响，分析表明利用Ｓ－ＲＥ－ＡＬＯＨＡ作为预订信道的多址方式及按报文占用数据信道方法可以减小报文传输延时并增加系统吞吐量。     

Java语言及其虚拟机技术探讨

随着Internet的迅猛发展，Internet编程语言Java愈来愈成为计算机行业的焦点。本文在简述了Java的主要特点后，重点对Java最关键的技术──虚拟机进行了深入的探讨。     

First observation of yrast band in odd-odd162Lu

High spin states of the odd-odd¹⁶²Lu nucleus have been studied via¹⁴⁷Sm(¹⁹F,4nγ)¹⁶²Lu reaction at 95 MeV beam energy. Level scheme for yrast band based onπ[h_11/2 v[i_13/2] quasiparticle configuration was established up to I ^π = (23^?) for the first time. This band shows the signature inversion in energy before backbending generally appeared in this mass region. It is stressed that the signature splitting in¹⁶²Lu is larger than that in the¹⁶⁰Tm nucleus.     

非晶态硒化镉薄膜瞬态光电特性

本文报道用真空热蒸发法淀积的非晶态硒化镉薄膜作光敏介质制备超快光电导探测器。用对撞脉冲锁模Nd:YAG激光器产生的超短光脉冲序列对探测器的响应时间进行检测,结果表明a-CdSe薄膜对皮秒(10^-12秒)级的超短光脉冲作用具有良好的瞬态响应光电特性,探讨a-CdSe薄膜快速弛豫过程的内在机理。     

钕玻璃激光放大器反转粒子数的荧光测定法

本文报道了通过测量钕玻璃激光放大器在一定泵浦功率下的荧光波形的方法,获得放大器中反转粒子数密度随时间的变化关系,进而得到反转粒子数密度达到最大值的时刻的测定方法及实验结果。     

Identification of peroxyacetic acid uroporphyrin I in the urine of patients with congenital erythropoietic porphyria by liquid chromatography and mass spectrometry

A new porphyrin, peroxyacetic acid uroporphyrin I, has been isolated from the urine of patients with congenital erythropoietic porphyria by reversed phase high performance liquid chromatography. The porphyrin was characterized by high resolution mass spectrometry and by typical chemical reactions of a peroxyacid.     

Fabricating blazing grating on NGD by photochemical etching

This paper tries to introduce the reader to the method of using photochemical re-action to copy holographic optical elements(HOEs)in relief.The holographic blazing gratingso copied is groove depth adjustable phase modulability enlarged through copying and 3.3times the diffraction efficiency(DE)of the original grating.It is expected that the newmethod will lead to the mass production of the light-weight HOEs at low cost.