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101.
High chromium white irons are important candidate materials for use in alumina refineries to combat wear and corrosion. The effect of exposure time on the formation of oxide films was studied in a 23% Cr white cast iron exposed at 260 °C in 110 g/l caustic soda solutions. It was found that whilst well‐formed octahedral M(II)O.M(III)2O3 spinel type oxides initially formed and spread across the surface of the material, these were gradually replaced by a background oxide with a higher Cr/Fe ratio and the morphology of the octahedral crystals became less well formed. Also, the oxidation was found to be predominantly in the matrix material, leaving carbide particles unsupported on the surface and in the later stages, significant corrosion was found along the carbide/matrix phase boundary. 相似文献
102.
103.
Becoming a better designer means getting better at what we do now while not getting lulled into accepting the status quo. To stay effective as designers, we need to continue to learn, adapt, keep an open mind, and work to perfect our craft. 相似文献
104.
Rebecca L. H. Chiu 《Urban Policy and Research》2013,31(4):455-468
Abstract Marketisation and privatization reforms implemented in Shanghai since 1980 have facilitated housing construction and the improvement of housing conditions. The multiplication of construction capital would have been impossible without an effective implementation of the consumption reforms and general improvements in the economy. 相似文献
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106.
The diffusive properties of two coextruded geomembranes, one with a polyamide inner core and the other with an ethylene vinyl-alcohol (EVOH) inner core, and a standard 0.53-mm (20-mil) linear low-density polyethylene (LLDPE) geomembrane were examined. Diffusion and sorption laboratory tests were performed to estimate the parameters controlling diffusive migration, including the partitioning, diffusion, and permeation coefficients of the geomembrane in both the aqueous and vapor phases. Results indicate a significant reduction in mass flux through the coextruded geomembranes compared to conventional LLDPE. The EVOH coextruded geomembrane had the lowest permeation coefficients (Pg) with a range of (2–6)×10?12?m2?s?1 for diffusion from the aqueous phase. These values for EVOH are upper bounds and the actual values may be lower than as stated. The polyamide (nylon) coextruded geomembrane had higher values than for EVOH, with a Pg range of (0.7–2.2)×10?11?m2?s?1 from the aqueous phase. The highest permeation coefficients were for the standard 20-mil LLDPE, which ranged from (0.6–1.1)×10?10?m2?s?1. Thus the permeation coefficient for LLDPE was about one order of magnitude greater than for the nylon coextruded and at least two orders of magnitudes higher than for the EVOH coextruded geomembrane. Both coextruded geomembranes showed decreased Pg values and therefore improved diffusive resistance to volatile organic compounds over traditional 0.56-mm PVC geomembranes. The EVOH geomembrane showed a 5–12-fold decrease in Pg in comparison to a 2.0-mm high density polyethylene geomembrane. 相似文献
107.
The effectiveness of a StormTreat system in treating stormwater from a commercial parking lot in Connecticut was evaluated. Flow-weighted composite samples were collected from StormTreat inflow and outflow during a 2-yr study. Bypass flow was not monitored. The StormTreat significantly (P < 0.05) reduced total suspended solids, total phosphorus, total Kjeldahl-N, total zinc, total copper, and fecal coliform bacteria on a concentration basis. The StormTreat system retained 49% total suspended solids, 74% total phosphorus, 44% total Kjeldahl-N, 45% total zinc, 29% total copper, 2% total lead on a mass basis, and 99% fecal coliform on a concentration basis. Treatment efficiency was not associated with storm size, chamber stage, discharge rate, or hydraulic retention time (r < 0.355). The system retained ammonia-N more efficiently during the summer than during the winter (P < 0.01) and retained total zinc less efficiently during the summer than during the winter (P < 0.05). Season did not significantly (P > 0.05) affect the treatment of other monitored water quality variables. The StormTreat system reduced the concentrations of stormwater pollutants commonly found in parking lot runoff. 相似文献
108.
Bellis DJ Satake K Noda M Nishimura N McLeod CW 《The Science of the total environment》2002,295(1-3):91-100
The annual growth rings and bark pockets of a 250-year-old Japanese oak (Quercus crispula), collected from the Nikko National Park, Japan in 2000 AD, were analysed by ICP mass spectrometry. The annual rings, sampled in 5-year increments, recorded Pb concentrations from 0.01 to 0.1 mg kg(-1) and there was no significant change in concentration with time. In contrast, bark pocket samples dating from 1875 to the present showed a progressive increase in Pb concentration with time, from approximately 0.1 to 10 mg kg(-1). Shoots of epiphytic moss growing on the tree trunk contained 17 mg kg(-1) Pb. The bark pockets recorded historical increases in airborne Pb pollution accompanying the industrialisation of Japan, which was initiated by the opening of Japan's borders from 1854. This increase was not reflected by the annual rings. The 206Pb/207Pb isotope ratio of the bark pockets decreased from approximately 1.18 to 1.16 from 1964 to the present, indicating changes in the sources of Pb pollution. The 206Pb/207Pb isotope ratio of the moss shoots was similar to the current bark (1.16). The data showed bark pockets to be more effective than annual rings for recording historical change in airborne lead pollution. 相似文献
109.
Sung KB Liang C Descour M Collier T Follen M Richards-Kortum R 《IEEE transactions on bio-medical engineering》2002,49(10):1168-1172
We have built a fiber-optic confocal reflectance microscope capable of imaging human tissues in near real time. Miniaturization of the objective lens and the mechanical components for positioning and axially scanning the objective enables the device to be used in inner organs of the human body. The lateral resolution is 2 micrometers and axial resolution is 10 micrometers. Confocal images of fixed tissue biopsies and the human lip in vivo have been obtained at 15 frames/s without any fluorescent stains. Both cell morphology and tissue architecture can be appreciated from images obtained with this microscope. 相似文献
110.
Fuller Rebecca L.; Luck Steven J.; Braun Elsie L.; Robinson Benjamin M.; McMahon Robert P.; Gold James M. 《Canadian Metallurgical Quarterly》2006,115(2):266
To investigate attentional impairment in schizophrenia, the authors examined the performance of 22 patients with schizophrenia and 16 healthy control subjects in 4 visual search tasks that varied in perceptual requirements and in the need for precise attentional control. The rate of search was slowed in the patients in all tasks. However, the degree of slowing was largest in tasks requiring precise attentional control and smallest in tasks that were perceptually difficult but required less attentional control. This pattern of results indicates that the primary impairment of attention in schizophrenia lies in the control of attention and not in the selection processes that operate once attention has been directed to an object. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献