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51.
To investigate the long-term trends and effects of decadal solar variability in the upper tropospheric ozone, data obtained from the Stratospheric Aerosol and Gas Experiment II (SAGE II) aboard the Earth Radiation Budget Satellite (ERBS) during the period 1985–2005 were analysed using a multifunctional regression model over the Indian region (8–40° N; 65–100° E). Analysis of time series spanning these years shows statistically insignificant trends (at the two-sigma level (95% confidence level)) at upper tropospheric pressure levels (10?16 km). This period covers two solar cycles, one lasting from 1985 to 1995 and the other from 1996 to 2005; these are referred to as decade I and decade II, respectively. Since temporal variation in ozone number density indicates 11 year periodicity, trends are statistically significant when calculated separately during each solar cycle. Trend analysis indicates statistically significant positive trends (0.7 ± 1.7% to 3.9 ± 2.9% year?1 during decade I, and 2.2 ± 1.6% to 4.5 ± 3.0% year?1 during decade II). In general, higher ozone trends are observed during decade II. Seasonal variation in trends during decade II shows increasing trends during the pre-monsoon (0.8?3.8% year?1), monsoon (0.8?7.1% year?1), and post-monsoon (2.8?8.0% year?1) seasons. The annually averaged solar signal in ozone is found to be of the order of around??5 ± 4.3% to??13.8 ± 6.7%/(100 sfu). Results obtained in the present study are also compared with those obtained by other researchers. 相似文献
52.
Ernest R. Bonner 《Journal of the American Planning Association. American Planning Association》2013,79(5):339-343
Though major universities exert considerable influence on their communities, the specific dimensions of their economic impact are rarely appreciated. This study of the University of Colorado uses an input-output frameivork to estimate the effects of University operation on the local economy. Estimates are also furnished of University economic influence on the Denver metropolitan area and the state. 相似文献
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55.
Martin Jack; Slemon Alan G.; Hiebert Bryan; Hallberg Ernest T.; Cummings Anne L. 《Canadian Metallurgical Quarterly》1989,36(4):395
We examined the conceptualizations of 23 (11 experienced and 12 novice) counselors, with respect to general counseling process and specific client concerns by means of a two-part conceptual mapping task (CMT). Analyses of the CMT data revealed an interaction effect of counselor experience and generality of conceptual task on the extensiveness of counselor conceptualizations. Experienced counselors displayed slightly more extensive conceptualizations on the general CMT and less extensive conceptualizations on the specific CMT. This interaction effect was interpreted as evidence that experienced counselors possess extensive abstract, general knowledge of counseling that they use to conceptualize specific instances of counseling efficiently and parsimoniously. On the other hand, novice counselors, who lack such abstracted knowledge, engage in more extensive, unique conceptual work for each separate client. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
56.
57.
Solutions of iron oxides in molten cryolite 总被引:1,自引:0,他引:1
All the iron oxides (FeO, Fe3O4, Fe2O3, and FeAl2O4) dissolve in cryolite-alumina melts to give solutions containing both Fe(II) and Fe(III). The factor controlling the Fe(II)/Fe(III)
ratio is the oxygen pressure, and experimental results are interpreted on that basis. Predictions are made of the variation
of solubility with oxygen pressure, and the standard potential of the Fe2+/Fe3+ redox couple is calculated. The anode and anode gas of an industrial Hall-Heroult cell appear to be insufficiently oxidizing
to cause significant conversion of Fe(II) to Fe(III). An anomaly in the liquidus diagrams for FeF2 – Na3AlF6 and FeO – Na3AlF6 is accounted for in terms of solid solution of FeF2 in cryolite.
This article is based on a presentation made at “The Milton Blander Symposium on Thermodynamic Predictions and Applications”
at the TMS Annual Meeting in San Diego, California, on March 1–2, 1999, under the auspices of the TMS Extraction and Processing
Division and the ASM Thermodynamics and Phase Equilibrium Committee. 相似文献
58.
Ernest Kurniawan A. S. Madhukumar Francois Chin 《Journal of Signal Processing Systems》2011,62(2):247-262
A low complexity antenna selection scheme for multicarrier MIMO (Multiple Input Multiple Output) broadcast systems is proposed
in this paper. Under special condition of single user in the system or when the number of subcarrier is only one, the system
reduces to conventional MIMO-OFDM (Orthogonal Frequency Division Multiplexing) system or MIMO-BC (Broadcast Channel) system
respectively. By analysing sub-optimal antenna selection schemes developed earlier for single user MIMO-OFDM systems and single
carrier MIMO-BC systems, one can see many similarities which can be extended to multicarrier MIMO broadcast systems. The proposed
method exploits these similarities to obtain a low complexity system design with acceptable performance. The performance of
the proposed scheme is studied via extensive simulation, and the computational complexity involved is compared to the conventional
scheme. A selection gain of approximately 0.5 b/s/Hz is shown to be achievable using only two out of three antennas, and the
proposed scheme is able to achieve up to 90% of the gain. This is achieved at a complexity that is significantly lower than
the conventional methods, hence the practical implementation of the proposed scheme can be justified. 相似文献
59.
Greene Ernest R. Avasthi Pratap S. Voyles Wyatt F. Seigel Rober 《IEEE transactions on bio-medical engineering》1986,(3):302-307
We compared simultaneous noninvasive and invasive determinations of blood velocity and flow in the renal arteries of 5 mongrel dogs. Noninvasive measurements of blood velocity spectra (?FN) were made using an ultrasonic echo-Doppler duplex scanner. Vessel diameters (DN) and Doppler angles (?N) were measured from sector images of the renal artery. Invasive measurements of blood velocity spectra (?F1) were made using a catheter Doppler velocimeter. Vessel lumen diameter (D1) and Doppler angle (?1) were measured angiographically. Using the Doppler and continuity equations, temporal mean blood velocities (VN, V1) and flows (QN, Q1) of five cardiac cycles were calculated. The ranges of velocity (8-48 cm/s) and flow (40-380 ml/min) were varied by pharmacological intervention. Standard linear regressions (n = 33) were Results suggest that simultaneous noninvasive echo-Doppler and invasive catheter Doppler measurements of canine renal artery blood velocity and flow correlate significantly. Nevertheless, large standard errors of the estimates exist which suggest that important systematic and experimental errors are present in both methods. 相似文献
60.
Wastewater and drinking water disinfection are typically achieved via chlorination, ozonation, or UV irradiation. However, there has been increased interest in recent years in alternative disinfectants. This interest came about primarily as a result of concerns over the toxicological effects of disinfection by-products created by conventional disinfection processes and the resistance of some recalcitrant microorganisms to these disinfectants. The work reported herein represents an investigation of the effect of an alternative disinfectant, gamma radiation, on the viability of three important waterborne microorganisms. Escherichia coli, coliphage MS-2, and Cryptosporidium parvum were chosen for this investigation as representative bacterial, viral, and protozoan microorganisms, respectively. A 60Co irradiator was used to expose test microorganisms to a controlled radiation dose. Experiments were performed for each of the test microorganisms to evaluate the effect of dissolved oxygen concentration and carbonate alkalinity on inactivation efficiency. For each microorganism, a strong effect of dissolved oxygen was observed, regardless of alkalinity. A subtle effect of alkalinity was observed for E. coli and coliphage MS-2, but only in air-saturated solutions. No significant alkalinity effect was observed for Cryptosporidium parvum. Inactivation kinetics were modeled for E. coli and coliphage MS-2 using single-target theory to calculate an inactivation rate constant. Multitarget theory was used to represent the inactivation response of Cryptosporidium parvum. The inactivation models based on target theory were found to provide suitable representations of experimental observations. 相似文献