203 research outputs found
Microstructure and mechanical properties of large size as-cast Ti-43Al-9V-0.2Y (at.%) alloy ingot from brim to centre
A Ti-43Al-9V-0.2Y (at.%) alloy ingot with the size of Š¤160Ć400mm was prepared by vacuum arc remelting (VAR). The microstructure of the as-cast Ti-43Al-9V-0.2Y alloy was composed of B2/Ī±ā/Ī³ lamellar colonies and massive B2 and Ī³ phases which were distributed along the boundaries of these lamellar colonies in the form of equiaxed grains. Based on the grain size variation along the radius direction of the ingot, the ingot could be divided into four ring regions from brim to centre. It has been understood that the grain size variation between these four regions was due to the interplay of the effects of the cooling rate and the yttrium content on solidified microstructures in these regions. Mechanical testing of the samples cut from these four regions showed that there existed a clear correlation between the yield strength and the average grain sizes of the four ring regions, which approximately conformed to a Hall-Petch relationship
Understanding Users\u27 Continuance of Facebook: The Role of General and Specific Computer Self-Efficacy
Prior research has distinguished general computer self-efficacy (CSE) and application-specific computer self-efficacy, but few studies have investigated the relationship between the two levels of CSE as well as their antecedents and consequences. With the increasing popularity of social networking sites such as Facebook, we are interested in assessing the role of general and specific CSE in predicting users\u27 continuance intention of these sites. An extended technology acceptance model with both cognitive and affective predictors is utilized to capture the decision process of Facebook users\u27 continuance intention. The proposed research model examined antecedents as well as consequences of both general CSE and specific CSE in Facebook. A survey was conducted for data collection. The results show that general CSE and specific CSE are closely related but play different roles in predicting continuance intention in Facebook through cognition and affect, and are affected differently by general computer and Facebook-specific experience
Time-domain Ad-hoc Array Speech Enhancement Using a Triple-path Network
Deep neural networks (DNNs) are very effective for multichannel speech
enhancement with fixed array geometries. However, it is not trivial to use DNNs
for ad-hoc arrays with unknown order and placement of microphones. We propose a
novel triple-path network for ad-hoc array processing in the time domain. The
key idea in the network design is to divide the overall processing into spatial
processing and temporal processing and use self-attention for spatial
processing. Using self-attention for spatial processing makes the network
invariant to the order and the number of microphones. The temporal processing
is done independently for all channels using a recently proposed dual-path
attentive recurrent network. The proposed network is a multiple-input
multiple-output architecture that can simultaneously enhance signals at all
microphones. Experimental results demonstrate the excellent performance of the
proposed approach. Further, we present analysis to demonstrate the
effectiveness of the proposed network in utilizing multichannel information
even from microphones at far locations.Comment: Accepted for publication in INTERSPEECH 202
Effects of Water Content and Particle Size on Yield and Reactivity of Lignite Chars Derived from Pyrolysis and Gasification
Water inside coal particles could potentially enhance the interior charāsteam reactions during pyrolysis and gasification. This study aims to examine the effects of water contents on the char conversion during the pyrolysis and gasification of Shengli lignite. The ex-situ reactivities of chars were further analyzed by a thermo gravimetric analyzer (TGA). Under the pyrolysis condition, the increase in water contents has monotonically decreased the char yields only when the coal particles were small (\u3c75 Ī¼m). In contrast, the water in only large coal particles (0.9ā2.0 mm) has clearly favored the increase in char conversion during the gasification condition where 50% steam in argon was used as external reaction atmosphere. The waved reactivity curves for the subsequent charāair reactions were resulted from the nature of heterogeneity of char structure. Compared to the large particles, the less interior charāsteam reactions for the small particles have created more differential char structure which showed two different stages when reacting with air at the low temperature in TGA
Hepatic arterial infusion chemotherapy versus sorafenib for advanced hepatocellular carcinoma with portal vein tumor thrombus: An updated meta-analysis and systematic review
BackgroundSorafenib was the first drug approved for advanced hepatocellular carcinoma (HCC). However, it is limited by poor efficacy for HCC with portal vein tumor thrombus (PVTT). Some studies suggested that hepatic artery infusion chemotherapy (HAIC) could provide survival benefits to patients with advanced HCC with PVTT.AimThe study aimed to compare the efficacy of HAIC versus sorafenib in patients with HCC accompanied by PVTT.MethodsThe PubMed, Embase, and Cochrane Library databases were searched for studies published until September 2022. Statistical analyses were performed using Stata SE 15 software.ResultsEight studies with 672 patients, 403 in the HAIC group and 269 in the sorafenib group, were included in the meta-analysis. The rates of complete response (RR=3.88, 95%CI:1.35-11.16, P=0.01), partial response (RR=3.46, 95%CI:1.94-6.18, P<0.0001), objective response rate (RR=4.21, 95%CI:2.44-7.28, P<0.00001) and disease control rate (RR=1.73, 95%CI:1.28-2.35, P=0.0004) were significantly higher in the HAIC group compared to the sorafenib group, whereas the progressive disease rate (RR=0.57, 95%CI:0.40-0.80, P=0.02) was significantly lower in the former. In contrast, the stable disease rate (RR=1.10, 95%CI (0.69-1.76), P=0.68) was similar in both groups. The overall survival (HR=0.50, 95%CI:0.40-0.63, P<0.05) and progression-free survival (HR=0.49, 95%CI:0.35-0.67, P<0.05) rates were significantly higher in the HAIC group compared to the sorafenib group.ConclusionHAIC has better efficacy against HCC with PVTT than sorafenib and may be considered an alternative to the latter. However, more high-quality randomized control trials and longer follow-ups are needed to verify our findings
N evolution and physiochemical structure changes in chars during co-pyrolysis: Effects of abundance of glucose in fiberboard
Ā© 2020 by the authors. The simple incineration of wood-based panels (WBPs) waste generates a significant amount of NOx, which has led to urgency in developing a new method for treating the N-containing biomass residues. This work aims to examine the N evolution and physiochemical structural changes during the co-pyrolysis of fiberboard and glucose, where the percentage of glucose in the feedstock was varied from 0% to 70%. It was found that N retention in chars was monotonically increased with increasing use of glucose, achieving ~60% N fixation when the glucose accounted for 70% in the mixture. Pyrrole-N (N-5) and Pyridine-N (N-6) were preferentially formed at high ratios of glucose to fiberboard. While the relevant importance of volatileāchar interactions to N retention and transformation could be observed, the volatileāvolatile reactions from the two feedstocks played a vital role in the increase in abundance of glucose. With the introduction of glucose, the porous structure and porosity in chars from the co-pyrolysis were dramatically altered, whereas the devolatilization of glucose tended to generate larger pores than the fiberboard. The insignificant changes in carbon structure of all chars revealed by Raman spectroscopy would practically allow us to apply the monosaccharides to the WBPs for regulating N evolution without concerns about its side effects for char carbon structures
The antioxidant methyl gallate inhibits fungal growth and deoxynivalenol production in Fusarium graminearum
Production of the Fusarium toxin deoxynivalenol (DON) is associated with oxidative stress and has been indicated to be part of an adaptive response to oxidative stress in the important wheat fungus Fusarium graminearum. In this study, we found that the antioxidant methyl gallate (MG) displays inhibitory effects against mycelial growth, conidial formation and germination, and DON biosynthesis in F. graminearum in a dose-dependent manner. Treatment with 0.05% (w/v) MG resulted in an abnormal swollen conidial morphology. The expression of the TRI genes involved in DON biosynthesis was significantly reduced, and the induction of Tri1-GFP green fluorescence signals in the spherical and crescent-shaped toxisomes was abolished in the MG-treated mycelium. RNA-Seq analysis of MG-treated F. graminearum showed that 0.5% (w/v) MG inhibited DON production by possibly altering membrane functions and oxidoreductase activities. Coupled with the observations that MG treatment decreases catalase, POD and SOD activity in F. graminearum. The results of this study indicated that MG displays antifungal activity against DON production by modulating its oxidative response. Taken together, the current study revealed the potential of MG in inhibiting mycotoxins in F. graminearum.
Graphical abstractThis work is supported by the National Natural Science Fund of China [31772118, 31901936], the Natural Science Fund of Jiangsu Province [BK20181246], the Key R&D Project for Tibet Autonomous Region of China [XZ202001ZY0038N]
Contrasting fate of western Third Pole's water resources under 21st century climate change
Seasonal melting of glaciers and snow from the western Third Pole (TP) plays important role in sustaining water supplies downstream. However, the future water availability of the region, and even todayās runoff regime, are both hotly debated and inadequately quantified. Here, we characterize the contemporary flow regimes and systematically assess the future evolution of total water availability, seasonal shifts, and dry and wet discharge extremes in four most meltwater-dominated basins in the western TP, by using a process-based, well-established glacier-hydrology model, well-constrained historical reference climate data, and the ensemble of 22 global climate models with an advanced statistical downscaling and bias correction technique. We show that these basins face sharply diverging water futures under 21st century climate change. In RCP scenarios 4.5 and 8.5, increased precipitation and glacier runoff in the Upper Indus and Yarkant basins more than compensate for decreased winter snow accumulation, boosting annual and summer water availability through the end of the century. In contrast, the Amu and Syr Darya basins will become more reliant on rainfall runoff as glacier ice and seasonal snow decline. Syr Darya summer river-flows, already low, will fall by 16ā30% by end-of-century, and striking increases in peak flood discharge (by >60%), drought duration (by >1 month) and drought intensity (by factor 4.6) will compound the considerable water-sharing challenges on this major transboundary river
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