We present a catalog of 37842 quasars in the Sloan Digital Sky Survey (SDSS) Data Release 7, which have counterparts within 6 ′′ in the Wide-field Infrared Survey Explorer (WISE) Preliminary Data Release. The overall WISE detection rate of the SDSS quasars is 86.7%, and it decreases to less than 50.0% when the quasar magnitude is fainter than i = 20.5. We derive the median color-redshift relations based on this SDSS-WISE quasar sample and apply them to estimate the photometric redshifts of the SDSS-WISE quasars. We find that by adding the WISE W1-and W2-band data to the SDSS photometry we can increase the photometric redshift reliability, defined as the percentage of sources with the photometric and spectroscopic redshift difference less than 0.2, from 70.3% to 77.2%. We also obtain the samples of WISE-detected normal and late-type stars with SDSS spectroscopy, and present a criterion in the z − W 1 versus g − z colorcolor diagram, z − W 1 > 0.66(g − z) + 2.01, to separate quasars from stars. With this criterion we can recover 98.6% of 3089 radio-detected SDSS-WISE quasars with redshifts less than four and overcome the difficulty in selecting quasars with redshifts between 2.2 and 3 from SDSS photometric data alone. We also suggest another criterion involving the WISE color only, W 1 − W 2 > 0.57, to efficiently separate quasars with redshifts less than 3.2 from stars. In addition, we compile a catalog of 5614 SDSS quasars detected by both WISE and UKIDSS surveys and present their color-redshift relations in the optical and infrared bands. By using the SDSS ugriz, UKIDSS YJHK and WISE W1-and W2-band photometric data, we can efficiently select quasar candidates and increase the photometric redshift reliability up to 87.0%. We discuss the implications of our results on the future quasar surveys. An updated SDSSWISE quasar catalog consisting of 101,853 quasars with the recently released WISE all-sky data is also provided.

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Tuning the electrical transport behavior and reducing the Schottky barrier height of nanoelectronic devices remain a great challenge. To solve this issue, the electronic properties and Schottky barrier of the...

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Butyl rubber (IIR) is widely used in tire inner liners and tubes, vulcanization bladders, and shock absorption materials due to its extremely low air permeability, excellent aging resistance, and good energy absorption. However, its low thermal conductivity affects its performance and the service life of the product, while it also limits its application. Therefore, the preparation of butyl rubber composites with high thermal conductivity is of great significance and practical value. This paper proposes the use of a dry ice expansion pre‐dispersion flocculation method to improve the thermal conductivity of butyl rubber composites by simultaneously doping graphene oxide (GO) and multiwalled carbon nanotube (MWCNTs) in butyl latex. The experimental results of this study show that the dry ice expansion pre‐dispersion method uses the huge volume expansion force of dry ice to break the nanofillers aggregates during sublimation, promote the dispersion of nanofillers, and achieve better modification effects. Moreover, GO and MWCNTs have good synergistic thermal conductivity, which can establish a complete three‐dimensional thermal conductivity network inside the composite. When 5 wt% of GO and 5 wt% of MWCNTs were added, GO/MWCNTs/IIR composites exhibited the highest thermal conductivity, which reached 0.423 W m−1 K−1 at 180°C.