Cloning and characterization of β-agarase AgaYT from Flammeovirga yaeyamensis strain YT

A bacterium with potent agar-degrading capability was isolated from the surface of a red algae, Gracilaria tenuistipitata. Based on phenotypic characteristics, 16S rDNA gene sequence and a phylogenetic analysis, this bacterium was identified and named as Flammeovirga yaeyamensis strain YT. PCR using homology-based degenerate primers was employed to clone any agarase gene belonging to GH16 family encoded in F. yaeyamensis strain YT. The resolved 1512 nucleotides revealed that the cloned gene, namely AgaYT, encodes a protein of 503 amino acids comprising a signal peptide, a glycosyl hydrolase catalytic module and a C-terminal domain with an unknown function. The recombinant protein r-AgaYT is an endo-type β-agarase hydrolyzing agarose to yield neoagarobiose and neoagarotetraose as the main hydrolytic products. The specific activity of r-AgaYT was determined about 178.6 U mg^{− 1} at 40°C and pH 8.0.     

Realization of effective light trapping and omnidirectional antireflection in smooth surface silicon nanowire arrays

We have successfully fabricated well-ordered silicon nanowire (SiNW) arrays of smooth surface by using a low-cost and facile Ag-assisted chemical etching technique. We have experimentally found that the reflectance can be significantly suppressed (<1%) over a wide solar spectrum (300-1000 nm) in the as-grown samples. Also, based on our bundled model, we have used rigorous coupled-wave analysis to simulate the reflectance in SiNW arrays, and found that the calculated results are in good agreement with the experimental data. From a further simulation study on the light absorption in SiNW arrays, we have obtained a photocurrent enhancement of up to 425% per unit volume of material as compared to crystalline Si, implying that effective light trapping can be realized in the as-grown samples. In addition, we have demonstrated experimentally and theoretically that the as-grown samples have an omnidirectional high-efficiency antireflection property.     

Light absorption mechanism in single c-Si (core)/a-Si (shell) coaxial nanowires

We have carried out detailed investigations on the light absorption mechanism in single crystalline silicon (c-Si) (core)/amorphous Si (a-Si) (shell) coaxial nanowires (NWs). Based on the Lorenz-Mie light scattering theory, we have found that the light absorption in the coaxial NWs relies on the leaky mode resonances and that the light absorption can be optimized towards photovoltaic applications when the a-Si shell thickness is about twice the c-Si core radius. The photocurrent has been found to be enhanced up to ～ 560% compared to c-Si NWs, and to be further enhanced up to ～ 60% by coating the nonabsorbing dielectric shells.     

Determination of priority polybrominated diphenyl ethers by isotope dilution gas chromatography(electron ionization)MS using 81Br-labeled standards

A mixture of (81)Br-labeled polybrominated diphenyl ethers (PBDEs), previously synthesized in our laboratory, was separated by liquid chromatography for the individual isolation of different (81)Br-labeled PBDEs containing from 3 to 6 bromine atoms. The different fractions were collected, and a mixed labeled standard was then prepared adequate for the determination of priority PBDEs (congeners 28, 47, 99, 100, 153, and 154) in environmental samples. The spike mixture was then characterized using gas chromatography(electron ionization)MS (GC(EI)MS) both in isotope composition and concentration in combination with multiple least-squares. Contamination from natural abundance BDEs 153 and 154 was detected in the spike mixture, and a new isotope dilution equation was developed to take into account the natural abundance contribution from the spike. The spike mixture was shown to be stable during at least 4 months, and no isotope exchange between natural abundance and labeled PBDEs was detected during this period of time. Finally, the (81)Br-labeled PBDEs standard was used for the determination of congeners 28 (+33), 47, 49, 99, 100, 153, and 154 in a standard reference material (Lake Michigan fish tissue SRM 1947) using three different sample to spike ratios. No methodological calibration needed to be prepared, as no isotopic effects were detected using this labeling mode. Concentrations found were in agreement with the certified concentrations (recoveries between 89% and 116%), and reproducibility was always below 7% RSD. Kragten procedure was used to calculate expanded uncertainties. Very low limits of detection were obtained for all compounds (between 0.02 and 0.9 ng·g(-1)) using the procedure developed here.     

Simulation study on electron heating characteristics in magnetic enhancement capacitively coupled plasmas with a longitudinal magnetic field

The electron heating characteristics of magnetic enhancement capacitively coupled argon plasmas in presence of both longitudinal and transverse uniform magnetic field have been explored through both theoretical and numerical calculations. It is found that the longitudinal magnetic field can affect the heating by changing the level of the pressure heating along the longitudinal direction and that of the Ohmic heating along the direction which is perpendicular to both driving electric field and the applied transverse magnetic field, and a continuously increased longitudinal magnetic field can induce pressure heating to become dominant. Moreover, the electron temperature as well as proportion of some low energy electrons will increase if a small longitudinal magnetic field is introduced, which is attributed to the increased average electron energy. We believe that the research will provide guidance for optimizing the magnetic field configuration of some discharge systems having both transverse and longitudinal magnetic field.     

绽放异彩的塞北明珠——榆林供电公司市场开拓及优质服务工作侧记

由于榆林地区特殊的电力现状和快速发展的电力市场需求,陕西省电力公司领导批示:榆林电力建设特事特办.正是在上级领导的关心、各部室的支持和各级政府的配合下,榆林供电人积极主动地开展创造性的工作,千方百计克服一切困难,不断拓展电力市场,加快电网建设的步伐.同时,以“国电榆林,服务一流“为内涵,开展“供电服务年“系列活动,全方位为用电客户提供优质服务,赢得了广大客户的认可,也最终赢得了电力市场.……     

MUSE and ABE Concept

1　IntroductionAccordingtoancientGreekmythologythereareninemuses ,eachofwhompresidedoveradifferentartorscience .Musehasbeencreditedasbeingthesourceofinspirationforartists ,writers ,poetsandmusicians.Inthispaper,theword“MUSE”isassociatedwithMobileUbiquitousServiceEnvironment ,avisionforfu tureworldofwireless ,whichalsosummonsinspira tionalinnovations .TheaimofMUSEistoenableuserstogetalwaysbestexperienceaccordingtotheirrequire mentsandpreferences ,wherevertheyareandwhenevertheyneed ,thro…     

A New Enhanced Fast Handover Algorithm in Hierarchical Mobile IPv6 Network

1　Introduction　MobileIPv6requirestheMobileNode (MN)toregisterwiththeHomeAgent (HA)andtheCorre spondentNode (CN)whenitchangesitspointofattachmentintheInternet[1～ 3] .Therefore ,thiscauseMobileIPv6toincurlongdelayintheregis tration process,andaddsignalingtraffictothebackbonenetworkespeciallywhentheHAandCNarefarawayfromtheMN .Inordertominimizethisdelay ,andthesignalingoverhead presentinMobileIPv6,literatures[4～7] proposeHierarchicalMobileIPv6(HMIPv6)architectureandafasthan dover…     

氧化物阴极(续)

4—3 氧化物涂层的电阻 碱土金属氧化物是一种宽禁带的半导体。其内由于带间跃迁出现的电流载流子浓度较低。实际上,全部导电电子都是由施主中心（杂质.晶格缺陷）电离产生的。体积中后者的浓度。处在与决定于阴极热电子活性之晶体表面上缺陷浓度的平衡状态中。这就引起了研究氧化物涂层体积之物理特性的兴趣《电导率、热电动势、霍尔效应等）。来看看所进行工作的主要结果。考虑到氧化物涂层的成份和结构的复杂性,它的电物理特性与活性状态有关系,在叙述多孔系统的数据时,将把它的性质与相应活性状态中单晶体的性质对照。