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71.
The temporal response of pulsed nano-electrospray ionization mass spectrometry (nano-ESI-MS) was studied and its influence on ion formation and detection was characterized. Rise and decay times for the mass resolved ion current were determined to be 20 ± 3 msec and 61 ± 5 msec, respectively, which led to a maximum pulse rate of 12 Hz. Pulsed nano-ESI operation was demonstrated from a multi-sprayer source controlled by a high voltage pulsing circuit constructed in-house. The desired source mode of operation (e.g. pulsing or continuous) can be realized solely by controlling the voltage applied to each sprayer. 相似文献
72.
AD Wagner RA Poldrack LL Eldridge JE Desmond GH Glover JD Gabrieli 《Canadian Metallurgical Quarterly》1998,9(16):3711-3717
Although numerous neuroimaging studies have examined the functional neuroanatomy supporting episodic memory for verbal material, there have been few investigations of non-verbal episodic encoding and retrieval. We used fMRI to directly compare prefrontal activation elicited by verbal and non-verbal material during encoding and during retrieval. Regardless of the mnemonic operation (encoding/retrieval), inferior prefrontal activation lateralized based on material type. Verbal encoding and retrieval resulted in greater left inferior prefrontal activation, whereas non-verbal encoding and retrieval resulted in greater right inferior prefrontal activation. The similarity between inferior prefrontal activity during encoding and during retrieval indicates that these mnemonic operations depend on shared processes mediated by inferior prefrontal regions. 相似文献
73.
GE Wyatt KA Desmond PA Ganz JH Rowland K Ashing-Giwa BE Meyerowitz 《Canadian Metallurgical Quarterly》1998,4(4):385-405
This study examines ethnic differences in sexual socialization and attitudes, sexual history and current practices, and the effects of treatment in 147 African American and White breast cancer survivors. Sex-related research in younger healthy populations has shown that cultural values associated with ethnicity influence sexual functioning, but small numbers of African American participants in previous research in breast cancer survivors has limited what we know about that population. In this study, there were few differences between the 2 ethnic groups in a predominantly well-educated, high-income, highly functional sample. However, African American women were significantly less likely to be comfortable with and to practice oral sex, self-touching, and masturbatory behaviors. White women were more likely to report that breast cancer had a negative impact on their sex lives. These differences in sexual repertoire and functioning should be noted by health care practitioners treating the sexual sequelae of breast cancer treatment. 相似文献
74.
The first recorded automobile fatality occurred in a small town in the Irish Midlands in 1869. Mary Ward, a celebrated microscopist, artist, astronomer and naturalist, fell from a steam carriage and died after crush injuries from its heavy iron wheels. The story of first automobile fatality characterizes the individual tragedy that is each premature death. It also illuminates the story of a remarkable Victorian scientific family. Among their many achievements was the building of a reflector telescope in the heart of rural Ireland that was the largest in the world for 74 years. 相似文献
75.
Desmond Tromans 《Metallurgical and Materials Transactions A》1981,12(8):1445-1453
Stress corrosion cracking of HY-180 steel (Fe-10 Ni-2 Cr-1 Mo-8 Co-0.12 C) was studied in aqueous 3.5 pct NaCI (pH = 6.5)
at 22 °C. The alloy was austenitized, water quenched and aged at 510 °C for 5 h. Specimens were of the precracked, double
cantilever beam (DCB) variety and exposure times extended up to 1000 h. The crack propagation rates (v) were studied as a
function of stress intensity(K,) under both freely corroding potentials(E ≈-0.36 VSHE) and potentials produced by coupling to Zn(E ≈ -0.82 VSHE. Crack fractography was studied by scanning electron microscopy and corrosion products were identified by electron diffraction
analysis. The stress intensity, KISCC, below which SCC could not be detected was ~45 MPa m1/2 for both freely corroding and Zn-coupled conditions. Analysis of the results showed that cracking was consistent with a hydrogen
embrittlement mechanism, irrespective of potential. Furthermore, comparison of the data with previous studies on a similarly
heat treated and closely related alloy (HY-180 M), containing 14 Co-0.16 C, showed no significant difference in SCC behavior,
provided comparison was made at similar electrochemical potentials. 相似文献
76.
Initiation of stress corrosion cracks in aluminum alloys 总被引:3,自引:0,他引:3
Rajeshwar Singh Pathania Desmond Tromans 《Metallurgical and Materials Transactions A》1981,12(4):607-612
Studies on initiation of stress corrosion cracking (scc) were conducted on notched rods of aged Al-8.6Mg, Al-21.5Zn and Al-2.6Mg-6.3Zn
alloys tested in aqueous solutions and water-containing ethanol solutions under free corrosion conditions. It was found that
there is a definite scc initiation period (t) preceding crack propagation. The crack initiation rate (1/t) increased with
increasing initial stress intensity (KI,) at the notch. The crack initiation rates were thermally activated with apparent activation energies of Q ≈ 40 to 60 kJ/mol
in the ethanol based solutions and Q ≈ 109 kJ/mol in aqueous solutions. Cathodic hydrogen precharging prior to scc decreased
the subsequent crack initiation period. The results were discussed in relation to a hydrogen mechanism of scc and shown to
be entirely consistent with the lattice decohesion model developed by Oriani.
Formerly Graduate Student with the University of British Columbia 相似文献
77.
The qualitative identification of the surface active agents commonly used in household detergent formulations is possible
using thin layer chromatography (TLC). Successful separations have been made when the samples are spotted on Aluminum Oxide
G and developed with isopropanol. A variety of specific reagents may be used to color the spots and thereby supplement the
Rf values as a means to identify the surfactants. The analysis can be made semi-quantitative if the separations are made using
an aluminum oxide column and collecting and fractions eluted with isopropanol and methanol.
Presented at the AOCS Meeting in Minneapolis, 1963. 相似文献
78.
A new test specimen configuration, designated the T-notch double cantilever beam (TNDCB), was developed, calibrated and employed
for a fracture mechanics study of stress corrosion cracking (SCC) of cold worked Type-316 austenitic stainless steel exposed
to hot aqueous solutions of 44.7 wt pct MgCl2. The effects of stress intensity (K
I
), temperature (T) and electrochemical potential (E) upon the crack velocity (v) and fractography were investigated. The stress intensity (K
ISCC
) below whichv became immeasurably small was ∼12 MN·m−3/2. Above this value, three regions of behavior were observed. Region I exhibitedK
I
dependent cracking followed by Region II which exhibitedK
I
independent cracking and an apparent activation energy of 63 to 67 kJ/mol, followed by Region III where cracking again became
dependent uponK
I
. The relative proportions of intergranular and transgranular crack paths were markedly dependent upon bothK
I
andE, and less sensitive toT. Crack velocity was insensitive to small changes inE with respect to the free corrosion potentials (E
corr), but could be terminated by an applied active potential of ∼−0.35 VSCE. The pH within the propagating crack was estimated to be <1.0 atE
corr, rising to ∼4.5 at −0.35 VSCE. The mechanism of SCC was discussed with respect to film rupture events caused by crack tip plastic deformation, adsorption
controlled processes on the metal surface, and hydrogen diffusion in the metal lattice.
Alan J. RUSSELL, formerly Research Student, University of British Columbia 相似文献
79.
Stress corrosion cracking of HY-180M steel was studied at 22°C in an aqueous solution of 3.5 pct NaCl (pH = 6.5). The steel
had a nominal weight percentage composition of 10Ni-14Co-2Cr-lMo-0.16C and was heat treated to yield a fracture toughness
value ofK
Ic ≃ 160 MPa . m1/2. The SCC velocity (v) was studied as a function of stress intensity (K
I) and electrochemical potential (E) using precracked compact tension specimens, a Ag/AgCl reference electrode and a 1000 h exposure test. Also, the polarization
behavior, microstructure, fractography and corrosion products were studied. The results showed that SCC was markedly dependent
uponE, and did not occur whenE =-0.52 VSHE (-0.72 VAg/AgCl), which corresponded closely to the thermodynamically reversible potential of iron. However, SCC occurred at a more noble
potential of-0.28 VSHE (-0.48 VAg/AgCl ) and at a less noble potential of-0.80 VSHE (-1.00 VAg/AgCl). The stress intensity below which SCC was not observed was KISCC ≃ 5.5 MPa . m1/2 at -0.28 VSHE and KISCC ≃ 60 MPa . m1/2 at -0.80 VSHE . Also, Region I behavior (v dependent uponK
1) and Region II behavior (v independent ofK
1) were observed. Cracking was considered to occur solely by hydrogen embrittlement at -0.80 Vshe, whereas anodic dissolution
processes played a necessary role, either directly or indirectly, in SCC at -0.28 VSHE . The indirect effects were discussed in relation to hydrolysis effects in the crack promoting hydrogen embrittlement and/or
corrosion product wedging stresses. 相似文献
80.
Canli Turhan; Zhao Zuo; Desmond John E.; Kang Eunjoo; Gross James; Gabrieli John D. E. 《Canadian Metallurgical Quarterly》2001,115(1):33
Functional imaging studies have examined which brain regions respond to emotional stimuli, but they have not determined how stable personality traits moderate such brain activation. Two personality traits, extraversion and neuroticism, are strongly associated with emotional experience and may thus moderate brain reactivity to emotional stimuli. The present study used functional magnetic resonance imaging to directly test whether individual differences in brain reactivity to emotional stimuli are correlated with extraversion and neuroticism in healthy women. Extraversion was correlated with brain reactivity to positive stimuli in localized brain regions, and neuroticism was correlated with brain reactivity to negative stimuli in localized brain regions. This study provides direct evidence that personality is associated with brain reactivity to emotional stimuli and identifies both common and distinct brain regions where such modulation takes place. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献