59 research outputs found

    The Research of Car-Following Model Based on Real-Time Maximum Deceleration

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    This paper is concerned with the effect of real-time maximum deceleration in car-following. The real-time maximum acceleration is estimated with vehicle dynamics. It is known that an intelligent driver model (IDM) can control adaptive cruise control (ACC) well. The disadvantages of IDM at high and constant speed are analyzed. A new car-following model which is applied to ACC is established accordingly to modify the desired minimum gap and structure of the IDM. We simulated the new car-following model and IDM under two different kinds of road conditions. In the first, the vehicles drive on a single road, taking dry asphalt road as the example in this paper. In the second, vehicles drive onto a different road, and this paper analyzed the situation in which vehicles drive from a dry asphalt road onto an icy road. From the simulation, we found that the new car-following model can not only ensure driving security and comfort but also control the steady driving of the vehicle with a smaller time headway than IDM

    Constitutive model of GH4720Li high temperature nickel base alloy at high strain rate and large temperature range

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    554-566The dynamic mechanical properties of GH4720Li nickel base superalloy under high and low strain rates in a wide temperature range have been studied, and a constitutive model with higher fitting progress have been established. The experimental results show that the abnormal phenomenon of dynamic mechanical properties of GH4720Li alloy appears under the condition of high strain rate. This is because the change of Cr (MO) content in precipitates and the change of precipitate morphology lead to the difference of dynamic mechanical properties of GH4720Li alloy at high and low strain rates. Besides, A new piecewise function model based on a phenomenological representation of the stress-strain curves is proposed to describe the constitutive equation of Nickel-based superalloy GH4720Li of stress-strain curves. Meanwhile, new methods to obtain the material constant k and C are proposed to predicted accurately the flow stress. The comparison between calculated values and experimental values based on the new constitutive modeling shows that these methods for obtaining material constants k and C are valid and the new function model is significant for establishing constitutive equations of Nickel-based superalloy GH4720Li in hot deformation processes

    Selective and Continuous Electrosynthesis of Hydrogen Peroxide on Nitrogen-doped Carbon Supported Nickel

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    Hydrogen peroxide is a widely used industrial oxidant, the large-scale production of which continues to be done by an indirect process. Direct electrosynthesis of hydrogen peroxide from aerial oxygen and water is a sustainable alternative, but this remains challenging because hydrogen peroxide is highly reactive and robust catalysts are vital. Here, we report direct and continuous electrosynthesis of hydrogen peroxide under alkaline conditions using a nitrogen-doped-carbon-supported nickel catalyst. Both experiment and theoretical calculations confirm that the existence of nickel particles suppresses the further reduction of hydrogen peroxide on Ni-N-C matrix. In air-saturated 0.1 M potassium hydroxide, the energy-efficient non-precious metal electrocatalyst exhibits a consistent Faraday efficiency over 95% at a steady rate of hydrogen peroxide production (15.1 mmol min−1 gcat−1) for 100 h. This sustainable, efficient, and safe process is an important step toward continuous production of hydrogen peroxide

    Genomic heterogeneity of multiple synchronous lung cancer

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    Multiple synchronous lung cancers (MSLCs) present a clinical dilemma as to whether individual tumours represent intrapulmonary metastases or independent tumours. In this study we analyse genomic profiles of 15 lung adenocarcinomas and one regional lymph node metastasis from 6 patients with MSLC. All 15 lung tumours demonstrate distinct genomic profiles, suggesting all are independent primary tumours, which are consistent with comprehensive histopathological assessment in 5 of the 6 patients. Lung tumours of the same individuals are no more similar to each other than are lung adenocarcinomas of different patients from TCGA cohort matched for tumour size and smoking status. Several known cancer-associated genes have different mutations in different tumours from the same patients. These findings suggest that in the context of identical constitutional genetic background and environmental exposure, different lung cancers in the same individual may have distinct genomic profiles and can be driven by distinct molecular events

    Genomic Analyses Reveal Mutational Signatures and Frequently Altered Genes in Esophageal Squamous Cell Carcinoma

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    Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide and the fourth most lethal cancer in China. However, although genomic studies have identified some mutations associated with ESCC, we know little of the mutational processes responsible. To identify genome-wide mutational signatures, we performed either whole-genome sequencing (WGS) or whole-exome sequencing (WES) on 104 ESCC individuals and combined our data with those of 88 previously reported samples. An APOBEC-mediated mutational signature in 47% of 192 tumors suggests that APOBEC-catalyzed deamination provides a source of DNA damage in ESCC. Moreover, PIK3CA hotspot mutations (c.1624G>A [p.Glu542Lys] and c.1633G>A [p.Glu545Lys]) were enriched in APOBEC-signature tumors, and no smoking-associated signature was observed in ESCC. In the samples analyzed by WGS, we identified focal (<100 kb) amplifications of CBX4 and CBX8. In our combined cohort, we identified frequent inactivating mutations in AJUBA, ZNF750, and PTCH1 and the chromatin-remodeling genes CREBBP and BAP1, in addition to known mutations. Functional analyses suggest roles for several genes (CBX4, CBX8, AJUBA, and ZNF750) in ESCC. Notably, high activity of hedgehog signaling and the PI3K pathway in approximately 60% of 104 ESCC tumors indicates that therapies targeting these pathways might be particularly promising strategies for ESCC. Collectively, our data provide comprehensive insights into the mutational signatures of ESCC and identify markers for early diagnosis and potential therapeutic targets

    The oyster genome reveals stress adaptation and complexity of shell formation

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    The Pacific oyster Crassostrea gigas belongs to one of the most species-rich but genomically poorly explored phyla, the Mollusca. Here we report the sequencing and assembly of the oyster genome using short reads and a fosmid-pooling strategy, along with transcriptomes of development and stress response and the proteome of the shell. The oyster genome is highly polymorphic and rich in repetitive sequences, with some transposable elements still actively shaping variation. Transcriptome studies reveal an extensive set of genes responding to environmental stress. The expansion of genes coding for heat shock protein 70 and inhibitors of apoptosis is probably central to the oyster's adaptation to sessile life in the highly stressful intertidal zone. Our analyses also show that shell formation in molluscs is more complex than currently understood and involves extensive participation of cells and their exosomes. The oyster genome sequence fills a void in our understanding of the Lophotrochozoa. Š 2012 Macmillan Publishers Limited. All rights reserved

    Carbon emissions tax policy of urban road traffic and its application in Panjin, China

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    <div><p>How to effectively solve traffic congestion and transportation pollution in urban development is a main research emphasis for transportation management agencies. A carbon emissions tax can affect travelers’ generalized costs and will lead to changes in passenger demand, mode choice and traffic flow equilibrium in road networks, which are of significance in green travel and low-carbon transportation management. This paper first established a mesoscopic model to calculate the carbon emissions tax and determined the value of this charge in China, which was based on road traffic flow, vehicle speed, and carbon emissions. Referring to existing research results to calibrate the value of time, this paper modified the traveler’s generalized cost function, including the carbon emissions tax, fuel surcharge and travel time cost, which can be used in the travel impedance model with the consideration of the carbon emissions tax. Then, a method for analyzing urban road network traffic flow distribution was put forward, and a joint traffic distribution model was established, which considered the relationship between private cars and taxis. Finally, this paper took the city of Panjin as an example to analyze the road traffic carbon emissions tax’s impact. The results illustrated that the carbon emissions tax has a positive effect on road network flow equilibrium and carbon emission reduction. This paper will have good reference value and practical significance for the calculation and implementation of urban traffic carbon emissions taxes in China.</p></div

    Vehicle population of Panjin from 2005 to 2011 <sup>*</sup> (vehicle).

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    <p>Vehicle population of Panjin from 2005 to 2011 <sup><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196762#t003fn001" target="_blank">*</a></sup> (vehicle).</p
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