Tm3+/Ho3+ codoped tellurite fiber laser

Continuous-wave and Q-switched lasing from a Tm 3+ /Ho 3+ codoped tellurite fiber is reported. An Yb 3+ /Er 3+ -doped silica fiber laser operating at 1.6μm was used as an in-band pump source, exciting the Tm 3+ ions into the F 4 3 level. Energy is then nonradiatively transferred to the upper laser level, the I 7 5 state of Ho 3+ . The laser transition is from the I 7 5 level to the I 8 5 level, and the resulting emission is at 2.1μm . For continuous wave operation, the slope efficiency was 62% and the threshold 0.1W ; the maximum output demonstrated was 0.16W . Mechanical Q switching resulted in a pulse of 0.65μJ energy and 160ns duration at a repetition rate of 19.4kHz

Feedback-enhanced algorithm for aberration correction of holographic atom traps

We show that a phase-only spatial light modulator can be used to generate non-trivial light distributions suitable for trapping ultracold atoms, when the hologram calculation is included within a simple and robust feedback loop that corrects for imperfect device response and optical aberrations. This correction reduces the discrepancy between target and experimental light distribution to the level of a few percent (RMS error). We prove the generality of this algorithm by applying it to a variety of target light distributions of relevance for cold atomic physics.Comment: 5 pages, 4 figure

Upper Rio Grande Valley - Texas Interindustry Study

The Interindustry Study of the Upper Rio Grande Valley indicates that the region is highly dependent on Federal government expenditures and export trade. The export-base industry in the region is highly dependent on imports and mostly related to outside firms. The manufacturing sector is quite limited to very few basic industries like primary metal, petroleum refining and apparels. These 3 industries have very low multipliers because the local supportive industry is not developed enough to provide the basic industries with a significant proportion of their input needs. The agricultural sector and the trades sector based on agricultural products have the highest multipliers among all local processing sectors because of their high dependence on local markets for their inputs. Unfortunately, their contribution to the gross regional product is minute because of their low level of output. These sectors should be encouraged to expand. The construction sections rank very high in the level of their outputs and their multipliers. However, they are highly dependent on government expenditures. A boom in regional construction will be quite helpful to the region insofar as most local processing sectors will be substantially affected by a rise in final demand for construction. The study shows that the regional processing sectors produced in 1967 an output valued at $1,804,573,000 in 1967 dollars. The region exported goods and services valued at$692 million but imported goods and services valued at $730 million

A Dusty Mg~II absorber Associated with the Quasar SDSS J003545.13+011441.2

We report on a dusty Mg~II absorber associated with the quasar SDSSJ003545.13+011441.2 (hereafter J0035+0114) at $z$=1.5501, which is the strongest one among the three Mg~II absorbers along the sight line of quasar. The two low redshift intervening absorbers are at $z$=0.7436, 0.5436, respectively. Based on the photometric and spectroscopic data of Sloan Digital Sky Survey (hereafter SDSS), we infer the rest frame color excess E(\bv) due to the associated dust is more than 0.07 by assuming a Small Magellanic Cloud (hereafter SMC) type extinction curve. Our follow-up moderate resolution spectroscopic observation at the 10-m Keck telescope with the ESI spectrometer enable us to reliably identify most of the important metal elements, such as Zn, Fe, Mn, Mg, Al, Si, Cr, and Ni in the associated system. We measure the column density of each species and detect significant dust depletion. In addition, we develop a simulation technique to gauge the significance of 2175-{\AA} dust absorption bump on the SDSS quasar spectra. By using it, we analyze the SDSS spectrum of J0035+0114 for the presence of a associated 2175-{\AA} extinction feature and report a tentative detection at $\sim$2$\sigma$ significant level.Comment: 24 Pages, 8 Figures, 4 Tables; Published on Ap

Characterization of 1D photonic crystal nanobeam cavities using curved microfiber

We investigate high-Q, small mode volume photonic crystal nanobeam cavities using a curved, tapered optical microfiber loop. The strength of the coupling between the cavity and the microfiber loop is shown to depend on the contact position on the nanobeam, angle between the nanobeam and the microfiber, and polarization of the light in the fiber. The results are compared to a resonant scattering measurement

Influence of Growth Conditions on the Structural and Opto-electronic Quality of GaAsBi

A systematic series of GaAsBi pin diodes was grown by MBE using different growth temperatures and Bi fluxes, to study the effect on the structural and opto-electronic properties of GaAsBi. The Bi contents of the diodes show both growth temperature and Bi flux dependences. The diodes grown at higher temperatures show evidence of long range inhomogeneity from X-ray diffraction (XRD) measurements, whereas samples of comparable Bi content grown at lower temperatures appear to have well defined, uniform GaAsBi regions. However, the high temperature grown diodes exhibit more intense photoluminescence (PL) and lower dark currents. The results suggest that growth temperature related defects have a greater influence on the dark current than bismuth related defects, and therefore GaAsBi devices should be grown at the highest temperature possible for the desired Bi content

High-resolution radiation mapping to investigate FDNPP derived contaminant migration

AbstractAs of March 2016, five years will have passed since the earthquake and ensuing tsunami that crippled the Fukushima Daiichi Nuclear Power Plant on Japan’s eastern coast, resulting in the explosive release of significant quantities of radioactive material. Over this period, significant time and resource has been expended on both the study of the contamination as well as its remediation from the affected environments. Presented in this work is a high-spatial resolution foot-based radiation mapping study using gamma-spectrometry at a site in the contaminated Iitate Village; conducted at different times, seventeen months apart. The specific site selected for this work was one in which consistent uniform agriculture was observed across its entire extent. From these surveys, obtained from along the main northwest trending line of the fallout plume, it was possible to determine the rate of reduction in the levels of contamination around the site attributable to the natural decay of the radiocesium, remediation efforts or material transport. Results from the work suggest that neither the natural decay of radiocesium nor its downward migration through the soil horizons were responsible for the decline in measured activity levels across the site, with the mobilisation of contaminant species likely adhered to soil particulate and the subsequent fluvial transport responsible for the measurable reduction in activity. This transport of contaminant via fluvial methods has already well studied implications for the input of contaminant material entering the neighbouring Pacific Ocean, as well as the deposition of material along rivers within previously decontaminated areas

China's energy-water nexus - assessment of the energy sector's compliance with the "3 Red Lines" industrial water policy

Increasing population and economic growth continue to drive China's demand for energy and water resources. The interaction of these resources is particularly important in China, where water resources are unevenly distributed, with limited availability in coal-rich regions. The “3 Red Lines” water policies were introduced in 2011; one of their aims is to reduce industrial water use, of which the energy sector is a part. This paper analyses current water withdrawals and consumption for all energy processes and assesses the sector's compliance with the industrial water policy under different scenarios, considering potential future policy and technological changes. The results show that future energy plans could conflict with the industrial water policy, but the amount of water used in the energy sector is highly dependant on technology choices, especially for power plant cooling. High electricity demand in the future is expected to be met mainly by coal and nuclear power, and planned inland development of nuclear power presents a new source of freshwater demand. Taking a holistic view of energy and water-for-energy enables the identification of co-benefits and trade-offs between energy and water policies that can facilitate the development of more compatible and sustainable energy and water plans.The authors would like to thank EPSRC and BP (Grant no. RG60538) for their funding support.This is the final published version. It first appeared at http://www.sciencedirect.com/science/article/pii/S0301421515001196#

Tracing the locality of prisoners and workers at the Mausoleum of Qin Shi Huang: First Emperor of China (259-210 BC)

The mausoleum complex of the First Emperor of China, Qin Shi Huang (259-210 BC), is one of the most famous and important archaeological sites in China, yet questions remain as to how it was constructed and by whom. Here we present isotopic results of individuals from the Liyi (n = 146) and Shanren sites (n = 14), both associated with the mausoleum complex. Those buried at Liyi represent the local workers/inhabitants of the Qin population, and the δ(13)C (−8.7 ± 1.5%) and δ(15)N (10.3 ± 0.7%) values indicate that they consumed predominately millet and/or domestic animals fed millet. In contrast, the Shanren individuals were prisoners forced to construct the mausoleum (found buried haphazardly in a mass grave and some in iron leg shackles), and their δ(13)C (−15.4 ± 2.9%) and δ(15)N (8.0 ± 0.6%) results indicate a more mixed C(3)/C(4) diet, with possibly less domestic animals and more wild game protein consumed. This pattern of decreased millet consumption is also characteristic of archaeological sites from southern China, and possible evidence the Shanren prisoners originated from this region (possibly the ancient Chu state located in modern day Hubei Province and parts of Hunan and Anhui Provinces). Further, this finding is in agreement with historical sources and is supported by previous ancient DNA evidence that the mausoleum workers had diverse origins, with many genetically related to southern Chinese groups