Subwavelength-diameter silica wires for low-loss optical wave guiding

Silica waveguides with diameters larger than the wavelength of transmitted light are widely used in optical communications, sensors and other applications. Minimizing the width of the waveguides is desirable for photonic device applications, but the fabrication of low-loss optical waveguides with subwavelength diameters remains challenging because of strict requirements on surface roughness and diameter uniformity. Here we report the fabrication of subwavelength-diameter silica 'wires' for use as low-loss optical waveguides within the visible to near-infrared spectral range. We use a two-step drawing process to fabricate long free-standing silica wires with diameters down to 50 nm that show surface smoothness at the atomic level together with uniformity of diameter. Light can be launched into these wires by optical evanescent coupling. The wires allow single-mode operation, and have an optical loss of less than 0.1 dB mm(-1). We believe that these wires provide promising building blocks for future microphotonic devices with subwavelength-width structures.     

区域平均温度计算的最优权重方法——Ⅰ.理论分析

资料空间覆盖不均匀给全球(或半球)及区域平均温度的计算造成了很大困难.在求全球(或半球)平均温度时,Jones,Hansen,Vinnikov等分别用了不同的方法来解决这一问题.Vinnikov等用最优权重方法,即在误差最小的前提下,求出不同纬度带上每一站的权重,而后用加权平均方法来计算全球(或半球)平均温度.Shen等在用最优权重方法求全球平均温度方面又做了一些工作,结果表明,全球只用60多个分布合适的台站便可得到精度甚高的平均温度.     

Microarray-Based Differential Expression Monitoring of 79 Novel Genes in Human Fetal Tissues

0　ＩｎｔｒｏｄｕｃｔｉｏｎＬａｒｇｅ ｓｃａｌｅｓｅｑｕｅｎｃｉｎｇａｎｄｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆｅｘｐｒｅｓｓｅｄｓｅｑｕｅｎｃｅｔａｇ(ＥＳＴ)ｔｅｃｈｎｏｌｏｇｙｈａｓｌｅｄｔｏｔｈｅｉｄｅｎｔｉｆｉｃａｔｉｏｎｏｆｈｕｎｄｒｅｄｓａｎｄｔｈｏｕｓａｎｄｓｏｆｇｅｎｏｍｉｃｓｅｑｕｅｎｃｅｓｆｒｏｍｖａｒｉｏｕｓｍｉｃｒｏｂｅｓｔｏｍｕｌｔｉｃｅｌｌｕｌａｒｅｕｋａｒｙｏｔｅｓａｎｄｐｌａｎｔｓ[1,2 ] .ＥｘｐｒｅｓｓｉｏｎａｎａｌｙｓｉｓｏｆｅａｃｈｋｎｏｗｎｇｅｎｅｏｒＥＳＴｕｓｉ…     

Effect of NaNO<Subscript>3</Subscript> concentration on anodic electrochemical behavior on the Sb surface in NaOH solution

The effect of NaNO₃ concentration on the anodic electrochemical behavior of antimony in 4 M NaOH solution was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses. The mechanism of NO₃- concentration effect on the anodic electrochemical behavior of antimony was proposed, and its availability was confirmed by experimental results. The effect of NaNO₃ on the anodic behavior of antimony in NaOH solution can be interpreted as a stepwise formation of different antimony compounds with different NaNO₃ concentrations. Metallic antimony is apt to be oxidized into Sb₂O₃ within the NaNO₃ concentration range of 0-0.48 M. NaSbO₃ can be found on the antimony surface when the NaNO₃ concentration increases gradually. Insoluable NaSbO₃ inhibits the anodic oxidation of antimony due to its shielding effect on the mass transport of the reactants and products. Surface morphology and composition were analyzed by X-ray photoelectron spectroscopy (XPS), scanning electronic microscopy (SEM), and electron dispersion spectroscopy (EDS) analyses. Results indicate that the anodic oxidation layer is composed of Sb₂O₃, NaSbO₃, and Sb. The atomic proportion of antimony in the form of NaSbO₃ increases with increasing NaNO₃ concentration due to the powerful oxidizing property of NaNO₃.     

Analysis on composition and inclusions of ballpoint pen tip steel

Ballpoint pen tip steel, a super free-cutting stainless steel, exhibits excellent corrosion resistance and good machining properties. In this study, inductively coupled plasma spectroscopy, metallographic microscopy, and scanning electron microscopy were used to determine the elemental contents in five ballpoint pen tips and their components, morphologies, and inclusion distributions. The results showed that the steels were all S-Pb-Te super free-cutting ferritic stainless steel. The free-cutting phases in the steels were mainly MnS, Pb, and small amounts of PbTe. MnS inclusions were in the form of chain distributions, and the aspect ratio of each size inclusion in the chain was small. The stress concentration effect could substantially reduce the cutting force when the material was machined. Some of the Pb was distributed evenly in the steel matrix as fine particles (1-2 μm), and the rest of the Pb was distributed at the middle or at both ends of the MnS inclusions. The Pb plays a role in lubrication and melting embrittlement, which substantially increases the cutting performance. PbTe was also usually distributed in the middle and at both ends of the MnS inclusions, and Te could convert the sulfides into spindles, thereby improving the cutting performance of the steel.     

加强反硝化条件下地下水中常见有机污染物苯和甲苯微生？…

利用实验室含水层特微环境实验，对地下水常见有机污染物苯和甲苯在厌氧反硝化条件下的微生物降解进行了研究。通过１０种方案实验结果的分析对比，所得重要结论如下：在加强了的反硝化条件，微生物利用ＮＯ３＾－作为电子受体降解苯和甲苯；降解苯和甲苯的反硝化细菌来自于含水层物质；微生物所需的宏量营养由苯，甲苯和硝酸盐提供，痕量元素来自于含水层物质；环境的酸碱条件对微生物降解具有重要影响，ｐＨ值过高或过低均抑制微生     

Research and design on a kind of CASE environment architectural style based on ToolBus

1.INTRODUCTION CASEenvironment,whichencompassesasetoftool suitesandtoolintegrationframeworks,isakindof complexsystemsoftware.It’sthemajorchallenges totheCASEenvironmenttosupporttheopenness distributionandteamworkbasedontheInternet SimilartosoftwarearchitectureofOS(operatingsys tem),softwarearchitectureofcurrentCASEenvi ronmentalsocanbedividedintothreetypes:mono lithic,layeredandToolBusstructures. Untilnow,mostCASEenvironmentshavebeen implementedinmonolithicorlayeredstructure…     

Structural basis for signal transduction by the Toll/interleukin-1 receptor domains

Toll-like receptors (TLRs) and the interleukin-1 receptor superfamily (IL-1Rs) are integral to both innate and adaptive immunity for host defence. These receptors share a conserved cytoplasmic domain, known as the TIR domain. A single-point mutation in the TIR domain of murine TLR4 (Pro712His, the Lps(d) mutation) abolishes the host immune response to lipopolysaccharide (LPS), and mutation of the equivalent residue in TLR2, Pro681His, disrupts signal transduction in response to stimulation by yeast and gram-positive bacteria. Here we report the crystal structures of the TIR domains of human TLR1 and TLR2 and of the Pro681His mutant of TLR2. The structures have a large conserved surface patch that also contains the site of the Lps(d) mutation. Mutagenesis and functional studies confirm that residues in this surface patch are crucial for receptor signalling. The Lps(d) mutation does not disturb the structure of the TIR domain itself. Instead, structural and functional studies indicate that the conserved surface patch may mediate interactions with the down-stream MyD88 adapter molecule, and that the Lps(d) mutation may abolish receptor signalling by disrupting this recruitment.