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11.
N. Verma Petrus C. Pistorius Richard J. Fruehan Michael Potter Minna Lind Scott R. Story 《Metallurgical and Materials Transactions B》2011,42(4):720-729
The formation of intermediate reaction products after calcium addition to aluminum-killed steel was studied. Steel samples
were taken from laboratory and industrial heats before and at various times after calcium treatment. Inclusions were characterized
by automated and manual scanning electron microscopy and X-ray microanalysis of polished cross sections and inclusions extracted
by dissolution of the steel. Industrial and laboratory melts containing more than 40 parts per million (by mass) of dissolved
sulfur showed calcium sulfide as the main reaction product after calcium injection, with calcium aluminates appearing later.
It is proposed that the calcium aluminates are formed by reaction between the calcium sulfide and the alumina. A laboratory
heat containing 7 parts per million of sulfur showed calcium oxide as the main initial calcium reaction product. A simple
mechanism is proposed for the modification of alumina inclusions by calcium, considering transient CaO and CaS formation. 相似文献
12.
We analyze the effect of directional antennas at the base station on the Doppler spectrum. It is well known that the Doppler spectrum is dependent on the probability density function (pdf) of the angle-of-arrival (AOA) of the multipath components at the mobile unit and the direction of the motion of the mobile. The Doppler spectrum is U-shaped, when the pdf of the AOA of the multipath components at the mobile is uniform. Here, however, we study the Doppler fading at the base station and assume that the scatterers are uniformly located around the mobile within a circle and derive the pdf of the AOA of the multipath components at the mobile when directional antennas are used at the base station 相似文献
13.
Leptomeningeal enhancement is usually infective or neoplastic in origin. We present a case in which a patient received total parenteral nutrition via a catheter unknowingly placed within the right vertebral artery. We postulate that the hyperosmolar nature of the infused solution induced temporary osmotic disruption of the blood-brain barrier, resulting in cortical blindness associated with localized leptomeningeal enhancement. 相似文献
14.
Mobile communications suffer from cochannel interference, adjacent channel interference and fading. The cell capacity or the number of users per cell is limited by the interference. In this paper we analyze a new blind adaptive array structure called the spectral correlation discriminator array (SCDA), designed to reject cochannel interference for advanced mobile phone service (AMPS) signals. The blind adaptive array exploits the spectral redundancy in the AMPS signals which arises due to the presence of the supervisory audio tone (SAT). SCDA is shown to provide an improvement of 25–30 dB in signal-to-interference plus noise ratio (SINR) in static multipath channels and 10–15 dB improvement of SINR in Rayleigh fading channels. The SCDA is compared to the least squares constant modulus array (LSCMA) and is shown to have better signal selectivity properties. The reduction in interference power can significantly reduce the frequency reuse factor. 相似文献
15.
ABSTRACT: Shelf life of pasteurized milk in Brazil ranges from 3 to 8 d, mainly due to poor cold chain conditions that prevail throughout the country and subject the product to repeated and/or severe temperature abuse. This study evaluated the influence of storage temperature on the microbiological stability of homogenized whole pasteurized milk (75 °C/15 s) packaged in high-density polyethylene (HDPE) bottle and low-density polyethylene (LDPE) pouch, both monolayer materials pigmented with titanium dioxide (TiO2 ). The storage temperatures investigated were 2, 4, 9, 14, and 16 °C. Microbiological evaluation was based on mesophilic and psychrotrophic counts with 7 log CFU/mL and 6 log CFU/mL, respectively, set as upper limits of acceptability for maintaining the quality of milk. The microbiological stability for pasteurized milk packaged in HDPE bottle and stored at 2, 4, 9, 14, and 16 °C was estimated at 43, 36, 8, 5, and 3 d, respectively. For milk samples packaged in LDPE pouch, shelf life was estimated at 37, 35, 7, 3, and 2 d, respectively. The determination of Q10 and z values demonstrated that storage temperature has a greater influence on microbiological shelf life of pasteurized milk packaged in LDPE pouch compared to HDPE bottle. Based on the results of this study, HDPE bottle was better for storing pasteurized milk as compared to LDPE pouch. 相似文献
16.
Ferreira Mauro E. Pistorius Petrus Christiaan Fruehan Richard J. 《Metallurgical and Materials Transactions B》2019,50(6):2498-2501
Metallurgical and Materials Transactions B - Because of interfacial and surface tension, micron-sized liquid oxide droplets are expected to change from spherical (when fully immersed in liquid... 相似文献
17.
18.
Song Shengqiang Zhao Junxue Pistorius Petrus Christiaan 《Metallurgical and Materials Transactions B》2020,51(3):891-897
Metallurgical and Materials Transactions B - The gangue content in iron ore pellets that are used to produce direct-reduced iron (DRI) affects the slag volume during subsequent electric furnace... 相似文献
19.
Kashuba A. I. Petrus R. Yu. Andrievskyi B. V. Solov’ev M. V. Semkiv I. V. Malyi T. S. Chylii M. O. Stakhura V. B. Shchepanskyi P. A. Franiv A. V. 《Materials Science》2020,55(4):602-608
Materials Science - We present the results of experimental investigations of the temperature behaviors of the volt-ampere characteristics of Tl4HgI6 and Tl4CdI6 crystals. The temperature dependence... 相似文献
20.
G. A. Il’chuk V. V. Kus’nézh R. Yu. Petrus’ V. Yu. Rud’ Yu. V. Rud’ V. O. Ukrainets 《Semiconductors》2007,41(1):52-54
The hexagonal modification of In2Se3 single crystal is grown by planar crystallization from nearly stoichiometric melt and by the vapor-phase method. For the first time, the Schottky barriers In/n-In2Se3, which are photosensitive in a wide incident-photon energy range of 1–3.8 eV at 300 K, are obtained. The nature of the interband photoactive absorption is studied. The energy-barrier height and interband optical-transition energy are estimated. It is concluded that the grown crystals can be used in broadband optical-radiation converters. 相似文献