中红外7×1硫化物光纤合束器的设计与制备

硫化物光纤合束器可以实现对多个中红外光源(2～5μm)的功率组合和光谱扩展,基于自研As₂S₃多模光纤,使用低温熔融拉锥技术制备得到7×1中红外光纤合束器,分析了拉锥区域的损耗产生机理,并表征和评估了合束器的传输效率和光束质量。实现了输入光纤合束端与输出光纤的高质量熔接(熔接点损耗低至0.45 dB,抗拉张力超过300 g),合束器平均传输效率约为80%,单通道最高输出功率为4.32 W,表现出了优良的传输特性和功率承载能力。     

镧对Al—Si共晶合金组织及性能的影响

采用光学显微镜、扫描电镜、电子探针及X射线衍射等方法对金属型铸造和砂型铸造条件下,镧变质Al-Si共晶合金的特点和规律进行了研究。结果发现,镧对Al-Si共晶合金具有较强的变质作用;镧的加入量、熔液状态、保温时间及搅拌作用等对镧的变质效果均有影响;镧的变质具有长效性,且存在变质的“潜伏期”;镧能使合金的拉伸强度(σ_b)和延伸率(σ_s)提高,但两者不同时达到最大值。     

一种用于分布式同步的令牌算法

本文提出了一种称为令牌算法的分布式同步算法.按此算法每达成一次互斥协议仅需发送信件N封,此处N为网络中结点的个数,而采用其它的几种分布式同步算法时需发送2N或更多的信件.本文还讨论了分布式同步算法的好环标准.按本文提出的标准,令牌算法是最佳的分布式同步算法.     

Local hydrated structure of an Fe2+/Fe3+ aqueous solution: an investigation using a combination of molecular dynamics and X-ray absorption fine structure methods

The hydrated shell of both Fe2+ and Fe3+ aqueous solutions are investigated by using the molecular dynamics (MD) and X-ray absorption structure (XAS) methods. The MD simulations show that the first hydrated shells of both Fe2+ and Fe3+ are characterized by a regular octahedron with an Fe-O distance of 2.08 for Fe2+ and 1.96 for Fe3+, and rule out the occurrence of a Jahn-Teller distortion in the hydrated shell of an Fe2+ aqueous solution. The corresponding X-ray absorption near edge fine structure (XANES) calculation successfully reproduces all features in the XANES spectra in Fe2+ and Fe3+ aqueous solution. A feature that is located at energy 1 eV higher than the white line (WL) in an Fe3+ aqueous solution may be assigned to the contribution of the charge transfer.     

铒离子掺杂的含LaF3纳晶氟氧化物玻璃陶瓷的制备及其发光性能

主要研究了热处理制度对掺杂Er^3＋离子的含有LaF3纳米晶体的氟氧化物玻璃陶瓷的上转换发光和近红外发光性质的影响。制备了ErF3掺杂的SiO2-Al2O3-Na2O-LaF3系统玻璃，将其在不同温度下处理不同的时间，测试其上转换和近红外的发光行为的变化，并相应进行了XRD测试，基于XRD数据计算了晶粒大小和结晶度，考察了热处理制度对该材料微观结构及发光性能的影响。结果表明：在一定的温度下保温，LaF3晶体从玻璃基体中析出，并且随着热处理温度的升高和时间的延长，晶粒不断长大，结晶度持续增加，因为上转换的发光与基质的声子环境密切相关，所以随着氟化物晶体的增多，相应的玻璃陶瓷的上转换发光的强度也增大，而在氟氧化物玻璃中检测不到上转换发光。但是，对于近红外1530nm处的铒离子发光，氟化物晶体的析出对于其发光性质并没有太大的影响。     

One-pot Synthesis of Isoxazolines Using Soluble Polymer-supported Acrylate

An eficient liquid-phase synthesis of isoxazolines through a 1,3-dipolar cycloaddition is described.Soluble polymer-supported acrylate reacted with nitrile oxides generated in-situ,followed by cleavage from the support giving corresponding isoxazolines in high yields and excellent purities.     

新型无机-有机杂化微孔晶体Cd3(BDC)0.5(BTC)2(DMF)(H2O)·3DMF·H3O·H2O的合成与结构

传统分子筛是以硅氧四面体和铝氧四面体为骨架的微孔晶体材料. 近年来, 以无机-有机结构单元为骨架组成的微孔晶体材料已引起人们的广泛关注[1～19]. 该类材料是由金属离子(或金属氧簇)与有机配体(大多数是芳香多酸和多碱)构成的建筑单元通过共价键或者分子间作用力构成的. 无机-有机杂化晶体材料有多种结构类型, 如1-D, 2-D, 3-D和笼状结构等.     

一种微穿孔板消声器

本文根据马大猷教授提出的“微穿孔板吸声体精确理论”，在对微穿孔板消声器结构参数与吸声特性之间的相互影响进行了分析的基础上，设计了微穿孔板消声器并将其应用在新舟60飞机APU(辅助动力装置)降噪的实际工程中，并通过编写的噪音数据采集分析程序，对降噪效果进行了测试和分析，验证出微穿孔板消声器对消除飞机的APU的排气噪声具有良好的消声效果，平均降噪7．16dB。     

一种不等带宽光学梳状滤波器

提出了一种新型—Michelson—三面镜FabryPerot型50GHz不等带宽光学梳状滤波器设计方案,分析和模拟表明:该器件将一路信道间隔为50GHz的输入信号分离成信道间隔为100GHz的奇偶两路输出信号,其中在3dB处,奇数信道带宽大于30GHz用于10Gb/s传输,偶数信道带宽大于60GHz用于40Gb/s传输对于将来的40Gb/s系统,该器件具有优势.     

Magnetic Sensing inside a Diamond Anvil Cell via Nitrogen-Vacancy Center Spins

The diamond anvil cell-based high-pressure technique is a unique tool for creating new states of matter and for understanding the physics underlying some exotic phenomena.In situ sensing of spin and charge properties under high pressure is crucially important but remains technically challenging.While the nitrogen-vacancy(NV)center in diamond is a promising quantum sensor under extreme conditions,its spin dynamics and the quantum control of its spin states under high pressure remain elusive.In this study,we demonstrate coherent control,spin relaxation,and spin dephasing measurements for ensemble NV centers up to 32.8 GPa.With this in situ quantum sensor,we investigate the pressure-induced magnetic phase transition of a micron-size permanent magnet Nd_2Fe_(14)B sample in a diamond anvil cell,with a spatial resolution of ～2μm,and sensitivity of ～20 μT/Hz~(1/2). This scheme could be generalized to measure other parameters such as temperature,pressure and their gradients under extreme conditions.This will be beneficial for frontier research of condensed matter physics and geophysics.