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排序方式: 共有626条查询结果,搜索用时 31 毫秒
51.
Polysilicon TFT structures for kink-effect suppression 总被引:1,自引:0,他引:1
Mariucci L. Fortunato G. Bonfiglietti A. Cuscuna M. Pecora A. Valletta A. 《Electron Devices, IEEE Transactions on》2004,51(7):1135-1142
Experimental results and numerical simulations of asymmetric fingered polysilicon thin-film transistors (AF-TFTs) are analyzed in detail. In the AF-TFTs, the transistor channel region is split into two zones with different lengths separated by a floating n/sup +/ region. This structure allows an effective reduction of the kink effect depending on the relative length of the two subchannels, without introducing any additional series resistance. In addition, an appreciable reduction of the leakage current is also observed. The AF-TFTs characteristics have been analyzed by two-dimensional numerical simulation and by modeling the device with two transistors in series. This model clarifies the mechanisms of kink effect suppression in AF-TFT. On the basis of this analysis, two new modified device structures for kink-effect suppression are also proposed and discussed. 相似文献
52.
Carlotta Lassandro Giuseppe Banderali Giovanni Radaelli Elisa Borghi Francesca Moretti Elvira Verduci 《International journal of molecular sciences》2015,16(8):19989-20000
Prevalence of metabolic syndrome is increasing in the pediatric population. Considering the different existing criteria to define metabolic syndrome, the use of the International Diabetes Federation (IDF) criteria has been suggested in children. Docosahexaenoic acid (DHA) has been associated with beneficial effects on health. The evidence about the relationship of DHA status in blood and components of the metabolic syndrome is unclear. This review discusses the possible association between DHA content in plasma and erythrocytes and components of the metabolic syndrome included in the IDF criteria (obesity, alteration of glucose metabolism, blood lipid profile, and blood pressure) and non-alcoholic fatty liver disease in obese children. The current evidence is inconsistent and no definitive conclusion can be drawn in the pediatric population. Well-designed longitudinal and powered trials need to clarify the possible association between blood DHA status and metabolic syndrome. 相似文献
53.
Kelber Miranda Alan Lima Vieira Marcos André Bechlin Felipe Manfroi Fortunato Alex Virgilio Edilene Cristina Ferreira José Anchieta Gomes Neto 《Food Analytical Methods》2016,9(7):1887-1894
Establishing fast, simple, low-cost, and efficient sample preparation procedures to determine elements in foodstuffs is a relevant aspect for nutritional and health purposes. For this reason, the recently proposed closed-vessel conductively heated digestion system (CHDS) was evaluated for the digestion of milk powder, chocolate powder, and soluble coffee samples aiming for Ca, Cu, Fe, K, Mg, Mn, Na, and Zn determinations by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) and Cd, Mo, and Se determinations by inductively coupled plasma mass spectrometry with tandem configuration (ICP-MS/MS). The accuracy was evaluated by analyzing two milk certified reference materials digested by the CHDS and a microwave oven for comparison. When using the CHDS, recoveries for the analytes varied from 91 to 104 %. For microwave digestions, recoveries within the 94–109 % intervals were obtained. The method was then applied to the samples. For comparative purposes, the analytes were also determined in the samples after microwave digestion, and the results between the two digestion systems showed no differences based on a paired t test at a 95 % confidence level. Similar analytical blanks were obtained because quartz digestion tubes were used in both digestion systems. The CHDS with quartz tubes is an interesting alternative for laboratories dedicated to large-scale routine analysis because volatile elements usually found in very low concentrations in food samples such as Cd and Se can also be determined. 相似文献
54.
Frank S
S Rogerson Zelia Azevedo Nlia Fortunato Victor A
P de Freitas 《Journal of the science of food and agriculture》2002,82(11):1287-1292
1,3‐Dimethoxybenzene was identified by GC–O, GC–MS and Kovats indices (polar Supelcowax, 1709; non‐polar Rtx‐5MS, 1158) as a new volatile component of port wine. Sensory evaluation described this compound as having a sweet medicinal odour with hazelnut, resinous and woody notes. Respective threshold limits in model wine and port wine were 21 and 47 µg l?1. Quantitative analysis by GC–MS, using a selected characteristic ion (m/z 138), indicated that young port wines from the 1998 vintage contained up to 3 µg l?1 whereas ports from the 1999 vintage contained up to 20 µg l?1. © 2002 Society of Chemical Industry 相似文献
55.
Stefania Vichi Cecilia Santini Nadia Natali Claudio Riponi Elvira López-Tamames Susana Buxaderas 《Food chemistry》2007,102(4):1260-1269
Volatile and semi-volatile compounds of French and American oak wood used in wine and spirits ageing were extracted by an Accelerated Solvent Extractor (ASE) and analysed by gas chromatography–mass spectrometry. More than 90 compounds were isolated, characterised and quantified after being separated on two chromatographic columns with distinct polarity. The main oak wood components were quantitatively determined by using standard reference compounds. In addition, a number of compounds, mainly guaiacol and syringol derivatives, were detected and characterised. In particular, 10 compounds were tentatively identified as lignin dimers derivatives, whose presence in oak wood chips or barrels for wine and spirits ageing had not been previously described. Several of the characterised compounds enabled a distinction to be drawn between medium and high toasted wood chips, independently of their geographical origin. 相似文献
56.
R Talevi R Gualtieri G Tartaglione A Fortunato 《Canadian Metallurgical Quarterly》1997,12(12):2773-2780
The mammalian zona pellucida contains several glycoproteins whose oligosaccharide moieties are known to play a key role in the interaction with spermatozoa. Since zona pellucida defects may represent one of the most likely causes of failed fertilization in human in-vitro reproduction, we have studied the carbohydrate composition and distribution over the human zona pellucida by means of lectins. Donated, not inseminated cumulus-oocyte complexes, from cohorts with high fertilization rates, and fertilization-failed oocytes from cohorts inseminated with proven fertile donor semen, were analysed using 11 fluorescein-labelled lectins, on deplasticized semi-thin epoxy sections. Results showed that wheat germ agglutinin (WGA), Maclura pomifera (MPA) and Pisum sativum (PSA) bound to the extracellular matrix bordering the zona pellucida-corona radiata interface of cumulus-oocytes complexes, while the zona pellucida was labelled by WGA, Concanavalin A (ConA) and PSA. WGA labelling and correlative electron microscopy on the cumulus-oocyte complexes demonstrated that this lectin is a useful tool to trace the cortical granule distribution in the human oocyte. Surprisingly, in the failed-fertilized oocytes the zona pellucida was also labelled by MPA and showed three different patterns: (i) labelling of the zona pellucida outer surface; (ii) uniform labelling; (iii) labelling of an outer zona pellucida layer with variable thickness. Comparative analysis of WGA and MPA labelling on single failed-fertilized oocytes demonstrated that MPA zona pellucida patterns are not related to the cortical reaction. The nature and meaning of the MPA pattern of failed-fertilized oocytes were discussed in the light of zona pellucida defects impairing sperm receptivity. 相似文献
57.
J W Freeland K E Gray L Ozyuzer P Berghuis Elvira Badica J Kavich H Zheng J F Mitchell 《Nature materials》2005,4(1):62-67
Transmission of information using the spin of the electron as well as its charge requires a high degree of spin polarization at surfaces. However, at surfaces this degree of polarization can be quenched by competing interactions. Using a combination of surface-sensitive X-ray and tunnelling probes, we show for the quasi-two-dimensional bilayer manganites that only the outermost Mn-O bilayer is affected: it is a 1-nm-thick insulator that exhibits no long-range ferromagnetic order, whereas the next bilayer displays the full spin polarization of the bulk. Such an abrupt localization of the surface effects is due to the two-dimensional nature of the layered manganite, and the loss of ferromagnetism is attributed to weakened double exchange in the reconstructed surface bilayer and a resultant antiferromagnetic phase. The creation of a well-defined surface insulator atop a fully spin-polarized bulk demonstrates the ability of two of the most demanding components of an ideal magnetic tunnel junction to self-assemble naturally. 相似文献
58.
Giuseppe Curr Marco Camalleri Denise Calì Francesca Monforte Fortunato Neri 《Microelectronics Reliability》2007,47(4-5):819
A detailed study of the interface state properties shown by the silicon/oxynitride/oxide gate layers used in Vertically Diffused PowerMOSFET (PowerVDMOS) technologies is reported. A quantitative analysis of interface states versus the specific N2O based nitridation process, extracted from current–voltage characteristics in depletion regime, provided a clear trend and turns to be of great importance for reliability performances of the final device. 相似文献
59.
Anabela Oliveira André B. Fortunato António M. Baptista 《Canadian Metallurgical Quarterly》2000,126(8):605-614
This paper investigates the generation of flow mass errors in finite-element shallow water models and the effect of these errors in the mass conservation of Eulerian-Lagrangian transport simulations. Flow mass errors are shown to be similar for several primitive and wave equation formulations. These errors occur primarily in areas of steep bathymetric gradients and near complex boundaries. Forcing Eulerian-Lagrangian transport simulations with nonconservative flow fields generates important mass imbalances, which can be mitigated by refining the flow grid. Comparatively, refining the transport grid only reduces marginally the mass errors. 相似文献
60.
OBJECTIVES: The contribution of ultrasonography to pretreatment morphological assessment of strictures of the anterior urethra and assessment of the risk of recurrence after internal urethrotomy. MATERIAL AND METHODS: 33 patients (16-89 years) operated by internal urethrotomy for stricture of the anterior urethra and followed for at least 6 months. Preoperative urethral ultrasonography, recording the number, length and degree of strictures and echostructure of the peristenotic fibrosis of the corpus spongiosium. RESULTS: Ultrasound visualization of all urethral strictures, with no false-positives and no false-negatives. 11 patients relapsed after a mean interval of 5.7 months (1-16 months), 22 patients did not present recurrence: mean interval: 15.5 months (6-36 months). Corpus spongiosum fibrosis associated with urethral stricture is isoechoic to the corpus spongiosum (19 cases) or hyperechoic to the corpus spongiosum (14 cases). No statistical correlation was observed between the echostructure of the fibrous tissue and the risk of recurrence after internal urethrotomy. CONCLUSION: Ultrasonography allows excellent analysis of the morphological characteristics of a stricture of the male anterior urethra. In our experience, and in contrast with the limited data of the literature, no correlation was observed between the echostructure of the peristenotic fibrosis and the risk of recurrence after internal urethrotomy. 相似文献