Synthesis and Crystal Structure of a New Potassium Yttrium Diphosphate Dihydrate KYP2O7·2H2O

The dihydrated potassium yttrium diphosphate, KYP2O7·2H2O, has been synthesized for the first time. Single-crystal XRD study has allowed the determination of its structure and correct formula. It crystallizes in the monoclinic system, space group P21/c, with the cell parameters a = 7.7069（3）, b = 10.5801（4）, c = 10.0204（5）A,β = 93.24（3）A, V= 815.76（6）A^3, Z= 4, Mr = 337.98, F（000） = 656, Dc = 2.752 g/cm^3 and/t = 8.073 mm^-1. The single-crystal structure was solved from 1856 unique reflections with the final R = 0.0365 and wR = 0.0772, refined with 119 parameters. The atomic arrangement of KYP2O7·2H2O is built by the P2O7 groups, the YO7 and the KO10 polyhedrons which are connected by corner and edge-sharing to form a three-dimensional framework. Water molecules are directly bonded to the Y and K atoms, and they are located in channels running along the a direction.     

Phase transformation and nanograting structure on TiO2 rutile single crystal induced by infrared femtosecond laser

In this paper, TitaiJum dioxide （TiO2） rutile single crystal was irradiated by infrared femtosecond laser pulses with repetition rate of 250 kHz. For a P-polarized femtosecond laser, the periodic nanograting structure on the ablation crater surface was formed . The periodicity is much less than the laser wavelength. The direction of nanograting alignment depends on the polarization laser beam. Micro-Raman spectra show that the intensity of Eg Raman vibrating mode of rutile phase increases and that of Alg Raman vibrating mode decreases apparently within the ablation crater. With the increase of irradiation time and laser average power, the Raman vibrating modes of anatase phase emerged. Rutile phase of TiO2 single crystal is partly transformed into anatase phase.[第一段]     

A Three-dimensional Neodymium（Ⅲ）- potassium（Ⅰ） Coordination Polymer

The title compound [NdK（btec）（H2O）2]n 1 was synthesized via the hydrothermal reaction of Zn（OAc）E·H2O, Nd（NO3）3 and KOH with 1,2,4,5-benzenetetra-carboxylic acid （H4btec）, and characterized by elemental analysis and infrared spectra. The crystal of 1 crystallizes in monoclinic, space group P21/c with a = 8.9023（3）, b = 7.8954（1）, c = 17.6249（5）A,β= 91.857（1）°, V= 1238.16（6）A^3, Z = 4, C10H6KNdO10, Mr= 469.49, Dc = 2.519 g/cm^3, F（000） = 900 andμ（MoKa） = 4.585 mm^-1. The final R = 0.0404 and wR = 0.0832 for 2197 observed reflections with I 〉 2σ（I） and R = 0.0431 and wR = 0.0854 for all data. X-ray diffraction reveals that the btec ligand serves as a μ16-bridging ligand to link the Nd（Ⅲ） and K（Ⅰ） atoms into a three-dimensional coordination polymer. Photoluminescent investigation shows that the title compound displays strong emission in the blue region, which may be attributed to an intraligand emission state.     

Single-mode and tunable VCSELs in the near- to mid-infrared

Single-mode, long-wavelength vertical-cavity surface-emitting lasers （VCSELs） in the near- to mid-infrared covering the wavelength range from 1.3 to 2.3 μm are presented. This wide spectral emission range opens applications in gas sensing and optical interconnects. All these lasers are monolithically grown in the InGaAlAs-InP material system utilizing a buried tunnel junction （BTJ） as current aperture. Fabricated with a novel high-speed design with reduced parasitics, bandwidths in excess of 10 GHz at 1.3 and 1.55 μm have been achieved. Therefore, the coarse wavelength division multiplexing （CWDM） wavelength range of 1.3 to 1.6 μm at 10 Gb/s can be accomplished with one technology. Error-free data-transmission at 10 Gb/s over a fiber link of 20 km is demonstrated. One-dimensional arrays have been fabricated with emission wavelengths addressable by current tuning. Micro-electro-mechanical system （MEMS） tunable devices provide an extended tuning range in excess of 50 nm with high spectral purity. All these devices feature continuous-wave （CW） operation with typical single-mode output powers exceeding 1 mW. The operation voltage is around 1 - 1.5 V and power consumption is as low as 10 - 20 mW. Furthermore, we have also developed VCSELs based on GaSb, targeting functionality of tunable diode laser spectroscopy （TDLS） applying a 1.84-μm VCSEL. at the wavelength range from 2.3 to 3.0 μm. The systems is shown by presenting a laser hygrometer     

隐形技术及其军事应用

 所谓隐形,就是利用多种不同的技术手段来降低武器装备不被探测系统发现,让其“看不见”,“摸不着”。隐形技术是传统伪装技术的一种应用与延伸,它的出现,使伪装技术由防御性走向了进攻性,由消极被动变为积极主动,不仅使自己由于隐身而获取主动权,而且还可以示假而迷惑对方,从而增强部队的生存能力,提高对敌人的威胁力。 隐形技术就是改变己方武器装备等目标的各种可探测信息特征,从而降低目标被对方探测系统发现概率的各种技术的统称。隐形技术又可分为有源隐形和无源隐形。目前人们所说的隐形技术,主要是指无源隐形。无源隐形,从物理学角度来讲,就是根据波的反射和吸收规律,在目标上采用吸收或透波材料.     

Unidirectional Quantum Remote Control： Teleportation of Control－State

We investigate the problem of teleportation of unitary operations by unidirectional control-state telepor-ration and propose a scheme called unidirectional quantum remote control. The scheme is based on the isomorphism between operation and state. It allows us to store a unitary operation in a control state, thereby teleportatSon of the unitary operation can be implemented by unidirectional teleportation of the control-state. We find that the probability of success for implementing an arbitrary unitary operation on arbitrary A~-qubit state by unidirectional control-state teleportation is 4^-M, and 2M ebits and 4M cbits are consumed in each teleportation.     

超长寿命热—超声疲劳行为

工作频率在15－30kHz的超声疲劳技术是一种可以获取十亿周级以上超长寿命疲劳数据的可行而有效的方法。试件在高频超声载荷作用下会不可避免地产生摩擦生热。本文在研究球墨铸铁材料的超高周疲劳性能的同时，利用一种非接触红外线自动测温系统对整个实验过程中的试件进行了温度测试，实验表明超长寿命试件的温度变化可由两段组成：①10^7周前的温度徙升及随后的短暂下降；②10^7周后的相对温度平衡稳定。研究还进一步探讨了超长寿命疲劳的温度和频率效应。     

BRISOL靶源的远控操作系统北大核心CSCD

北京放射性核束装置在线同位素分离器(Beijing Radioactive Ion-beam Facilities Isotope Separator On-line)利用回旋加速器提供的100 Me V高能质子束轰击靶材料产生放射性核束。高能质子束轰击靶材料产生的最高10^(14)n/s的中子及很强的γ射线会对靶附件的设备造成严重的活化。为了解决靶源系统设备的维护问题,靶源系统采用模块化设计。靶源系统共分为3个模块,每个模块具有独立的水冷、供电及电信号馈入。真空、水、电、气等可以伴随模块的插拔自动接通或者断开。各模块可以通过特制的吊钩远程抓取或者释放,借助监控系统,实现各个模块从靶源间到热室的远程转运。该系统已完成了安装和调试,并已投入使用。     

新型透水坩埚在红外线吸收法测定连铸保护渣游离碳含量中的应用

准确分析连铸保护渣中的游离碳成分 ,对提高连铸坯质量和连铸操作的稳定性都起着非常重要的作用。近年奉冬文[1] 及杜建民[2 ] 曾分别发表了难熔碳化物中游离碳的快速测定及铁沟料中游离碳和碳化硅的高频炉燃烧红外光谱测定。但关于连铸保护渣中游离碳的测定迄今尚未见报道。作者等于1998～ 2 0 0 1年间 ,按冶信标院的要求起草了连铸保护渣游离碳化学分析行业标准。其方法是将试样经酸溶分解 ,以玻璃漏斗加衬瓷滤片和酸洗石棉过滤 ,转移至瓷舟或坩埚中 ,用管式炉内燃烧气体容量法或红外线吸收法进行测定。1　仪器与试剂ＣＳ 4 44型红外线吸…