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91.
The electrical properties of sets of simultaneously grown p-type polycrystalline Si films, deposited by SiH4 pyrolysis on polycrystalline high-purity alumina substrates and B-doped during growth, were determined by Hall-effect measurements
in the temperature range 77-420K as functions both of impurity doping concentration N (~10l5 to ~1020cm−3) and average grain size (≈1 to ≈125μm) in the film. Room temperature data showed rapidly increasing resistivities and rapidly
decreasing free-carrier concentrations for doping below a critical concentration Nm and distinct mobility minima at that concentration, with the value of Nm being larger the smaller the average grain size. Measurements as a function of sample temperature showed the intergrain barrier
height Eb, decreasing from a maximum value of ~0.4eV at the critical concentration to very small values (~0.01eV) for concentrations
above 1019cm−3, with a functional dependence close to Eb ∝l/N1/2 and Eb for any given concentration being larger the smaller the average grain size. Results are interpreted in terms of the grain-boundary
trapping model. Trapped carrier densities in the grain boundaries were calculated to range from ~5×l011cm−2 at N≈Nm to ~5×l012cm−2 for N>1019cm−3, the density being higher the smaller the grain size, and evidence was found for an energy distribution of traps in the Si
bandgap, rather than a fixed density at a single discrete energy level. The observed relationship between Nm and average grain size nearly coincides with that of the model for films with ~lμm grain size but sharply departs from it
for larger grain sizes, indicating probable applicability of the model for grain sizes up to that range.
aThis work was supported by the U.S. Department of Energythrough its San Francisco Operations Office under Contract DE-AC03-79ET23045
and monitored by the Solar Energy Research Institute, Golden, CO.
bThese results were first described at the 22nd Electronic Materials Conference, Ithaca, NY, June 21–27, 1980, Paper No. M4. 相似文献
92.
In a study with 133 children in Grades 1, 3, and 5, a brief training procedure designed to improve performance on the Children's Embedded Figures Test, a test of visual ability, resulted in significant improvement for girls but not for boys. No sex difference was observed among children receiving this training. The implications for theories of sex differences in visual–spatial ability are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
93.
94.
Soontae?KimEmail author Narayanan?Vijaykrishnan Mahmut?Kandemir Mary?Jane?Irwin 《Design Automation for Embedded Systems》2004,9(1):5-18
As technology scales down into deep-submicron, leakage energy is becoming a dominant source of energy consumption. Leakage energy is generally proportional to the area of a circuit and caches constitute a large portion of the die area. Therefore, there has been much effort to reduce leakage energy in caches. Most techniques have been targeted at cell leakage energy optimization. Bitline leakage energy is critical as well. To this end, we propose a predictive precharging scheme to reduce bitline leakage energy consumption. Results show that energy savings are significant with little performance degradation. Also, our predictive precharging is more beneficial in more aggressively scaled technologies. 相似文献
95.
Effect of recombinant cytokines on leucocytes and physiological changes in bovine mammary glands during early involution 总被引:2,自引:0,他引:2
Wedlock DN McCarthy AR Doolin EE Lacy-Hulbert SJ Woolford MW Buddle BM 《The Journal of dairy research》2004,71(2):154-161
We examined the effects of administering recombinant bovine cytokines to non-lactating dairy cows and measured mammary gland leucocytes and the involution process. After the final milking, groups of cows were given an intramammary infusion of cytokine in two quarters. These cytokines were recombinant bovine interleukin-2 (rbolL-2) (2 x 10(5) units, n = 6), recombinant bovine granulocyte-macrophage colony stimulating factor (rboGM-CSF) (500 microg, n = 4) and recombinant bovine interleukin-1beta (rbolL-1beta) (10 microg, n = 10). Each animal also received an infusion of phosphate-buffered saline (PBS) in the other two quarters as controls. The rbolL-2 and rboGM-CSF were produced in a yeast expression system, while rbolL-1beta was produced in Escherichia coli. Leucocyte numbers, bactericidal activity of leucocytes, and concentrations of citrate and lactoferrin in quarter secretion samples were monitored after infusion of cytokine or PBS. Infusion of rbolL-2 had minimal effect on leucocyte numbers and concentrations of citrate and lactoferrin. Both rboGM-CSF and rbolL-1beta induced a rapid increase in the number of neutrophils and macrophages compared with control PBS quarters. Concentrations of lactoferrin in secretions were increased by rboGM-CSF and rbolL-1beta compared with control PBS quarters. In addition, infusion of glands with rbolL-1beta lowered the citrate:lactoferrin molar ratio compared with PBS control quarters. The results indicate that intramammary infusion of either rboGM-CSF or rbolL-1beta at cessation of milking immediately increased the number of phagocytic cells in the gland. These cytokines, in particular rbolL-1beta, also increased the rate of mammary gland involution during the early dry period. 相似文献
96.
Roberts Alan H.; Schuler Joanne; Bacon Jane G.; Zimmermann Robert L.; Patterson Robert 《Canadian Metallurgical Quarterly》1975,84(3):272
Proposed to (a) replicate earlier findings that human Ss could voluntarily control peripheral skin temperature, (b) test the hypothesis that hypnotic susceptibility and the capacity for absorbed, imaginative attention would enhance autonomic learning and performance, and (c) demonstrate a learning effect, if one exists. A comparison was made with 7 Ss who scored high and 7 Ss who scored low on both a modified version of the Harvard Group Scale of Hypnotic Susceptibility and the Tellegen Absorption Scale. Auditory feedback was used to train Ss to produce a difference in skin temperature in one hand relative to the other in a direction specified by the E. Large and reliable performance and learning effects were found, but they were unrelated to hypnotic susceptibility or the capacity for absorbed, imaginative attention. Variables that might account for individual differences in learning and performance are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
97.
Bhargava A Jukes M Lambo J Kihamia CM Lorri W Nokes C Drake L Bundy D 《Food and nutrition bulletin》2003,24(4):332-342
To investigate the relationships between helminth infections and iron status among school-aged children, 1,115 Tanzanian children in grades 2 through 5 were randomly assigned to treatment or control groups. The children in the treatment group were screened for infection with Schistosoma haematobium and hookworm at baseline, 3 months, and 15 months; infected children were given albendazole against hookworm and praziquantel against schistosomiasis. The control group received a placebo and did not undergo parasitological screening until 15 months after the baseline. Hematological variables were compared between the treatment and control groups. The main results were, first, that the hemoglobin concentration significantly improved after treatment for hookworm (p < .001) by 9.3 g/L in children treated for hookworm only and by 8.8 g/L in children treated for hookworm and schistosomiasis. The ferritin concentration also improved in children treated for schistosomiasis (p = .001) or hookworm (p = .019). Second, a longitudinal analysis of the data from the children in the control group showed that hookworm and schistosomiasis loads were negatively associated with hemoglobin and ferritin concentrations. Moreover, ferritin concentrations increased as C-reactive protein levels increased. Overall, the results showed that anthelmintic treatment is a useful tool for reducing anemia in areas with high hookworm and schistosomiasis endemicity. The empirical relationship between ferritin and C-reactive protein indicated that simple procedures for adjusting cutoff points for the use of ferritin as an indicator of low iron stores were unlikely to be useful in this population. 相似文献
98.
This paper explores the growing phenomenon of international co-productions in the film industry. We argue that the rise of co-productions is part of a wider narrative of financial and institutional innovation shaping industrial organization in the film industry. This narrative centres on film finance as a central risk distribution mechanism, and discusses how changes in film support policy, increased tax competition, the search for finance and an abundance of inflowing capital are increasingly driving industrial dynamics in the film industry. 相似文献
99.
Simoni Jane M.; Pantalone David W.; Plummer Mary D.; Huang Bu 《Canadian Metallurgical Quarterly》2007,26(4):488
Objective: To determine the efficacy of a peer-led social support intervention involving support groups and telephone contacts compared with standard clinical care to enhance antiretroviral medication adherence. Design: Randomized controlled trial with follow-up. Participants were 136 HIV-positive indigent mainly African American and Puerto Rican men and women recruited from an outpatient clinic in the Bronx, New York. The 3-month intervention was delivered by other HIV-positive clinic patients trained in addressing barriers to adherence and sensitively providing appraisal, spiritual, emotional, and informational adherence-related social support. Main outcome measures: Medical chart-abstracted HIV-1 RNA viral load, antiretroviral adherence according to electronic drug monitoring and participant self-report, and social support and depressive symptomatology. All assessments conducted at baseline, 3 months, and 6 months. Results: Intent-to-treat and as-treated analyses indicated no between-conditions intervention effects on the primary outcome of HIV-1 RNA viral load or any of the secondary outcomes at immediate postintervention or follow-up. Post hoc analyses within the intervention condition indicated greater intervention exposure was associated with higher self-reported adherence, higher social support, and lower depressive symptomatology at follow-up, even after controlling for baseline adherence. Conclusion: Null findings, consistent with the limited literature on efficacious highly active antiretroviral therapy (HAART) adherence interventions, may be due to insufficient exposure to the intervention, its low intensity, or the nature of the sample-a heterogeneous HAART-experienced group of patients with high levels of substance use and multiple other competing stressors. Overall, findings highlight the need for more comprehensive and intensive efforts to battle nonadherence. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
This research examined students’ language use and interaction styles in text-based, computer-mediated discussion groups. The contributions of 197 introductory psychology students (149 females, 48 males) participating in asynchronous computer-mediated communication (CMC) were collated. Both quantitative and qualitative methods were used, under the methodological framework of qualitative content analysis [Mayring, P. (2000). Qualitative Content Analysis. Forum Qualitative Sozialforschung/Forum: Qualitative Social Research [online] 1. http://qualitative-research.net/fqs-e/2-00halt-e.htm Accessed 10.06.2001]. A coding system, which incorporated the creation of ‘supercodes’, was developed using Atlas.ti 4.2 and used to code 699 student postings in total. The frequencies of coded categories were analysed using χ2 statistics in SPSS 10. It was found that males and females were similar regarding use of individual linguistic variables, with the exception of intensifiers as more females used them than males. However, significant gender differences were found in use of many of the stylistic variables and the supercode analysis showed overall gender-related patterns in interaction styles. Males were more likely to use authoritative language and to respond negatively in interactions, than females. On the other hand, females were more likely to explicitly agree and support others and make more personal and emotional contributions, than males. The results suggest that gendered power differentials may carry over into online contexts, which has implications for the use of CMC in education. 相似文献