60 research outputs found

    Correlations for the ignition delay times of hydrogen/air mixtures

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    Correlations for the ignition delay times of hydrogen/air mixtures were developed using the method of High Dimensional Model Representation (HDMR). The hydrogen/air ignition delay times for initial conditions over a wide range of temperatures from 800 to 1600 K, pressures from 0.1 to 100 atm, and equivalence ratios from 0.2 to 10 were first calculated utilizing the full chemical mechanism. Correlations were then developed based on these ignition delay times. Two forms of correlations were constructed: the first one is an overall general model covering the whole range of the initial conditions; while the second one is a piecewise correlation model valid for initial conditions within different sub-domains. The performance of these correlations was studied through comparison with results from the full chemical mechanism as well as experimental data. It was shown that these correlations work well over the whole range of initial conditions and that the accuracy can be significantly improved by using different piecewise correlations for different sub-domains. Therefore, piecewise correlations can be used as an effective replacement for the full mechanism when the prediction of chemical time scale is needed in certain combustion modeling.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000286389300013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Multidisciplinary SciencesSCI(E)6ARTICLE2215-2215

    The Mechanism for GNSS-Based Kinematic Positioning Degradation at High-Latitudes Under the March 2015 Great Storm

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    In this study, we focus on the kinematic precise point positioning (PPP) solutions at high-latitudes during the March 2015 great geomagnetic storm. We aim to discover the mechanism behind the positioning degradation from the perspective of the impacts of the storm-induced ionospheric disturbance on the global navigation satellite system (GNSS) data processing. We observed that the phase scintillation dominated the amplitude scintillation at high-latitudes and the variation pattern of the rate of total electron content index (ROTI) was consistent with that of the phase scintillation during the storm. The kinematic PPP errors at high-latitudes were almost three times larger than those at the middle- and low-latitude, which were accompanied by large ROTI variations. From the perspective of GNSS data processing, the large positioning errors were also found to be related to the large number of satellites experiencing cycle slips (CSs). Based on the lock time from the ionospheric scintillation monitoring receiver, we found that a large amount of the CSs was falsely detected under the conventional threshold of the CS detector. By increasing such threshold, the kinematic positioning accuracy at high-latitudes can be improved to obtain similar magnitude as at middle- and low-latitude. The improved positioning accuracy may suggest that the ionospheric disturbance induced by the geomagnetic storm at high-latitudes has minor effects on triggering the CSs. Therefore, precise positioning can be achieved at high-latitudes under geomagnetic storms, given that the CS problem is well addressed.The study is funded by the National Natural Science Foundation of China (No.42004012, 42004025), the Natural Science Foundation of Shandong Province, China (No.ZR2020QD048), the State Key Laboratory of GeoInformation Engineering (No.SKLGIE2019-Z-2-2), the State Key Laboratory of Geodesy and Earth's Dynamics (No. SKLGED-2021-3-4) and by the project RTI2018-094295-B-I00 funded by the MCIN/AEI 10.13039/501100011033, which is co-funded by the FEDER programme.Peer ReviewedPostprint (published version

    Intermediate-band Surface Photometry of the Edge-on Galaxy: NGC 4565

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    We present a deep, 42.79 hr image of the nearby, edge-on galaxy NGC 4565 in the Beijing-Arizona-Taipei-Connecticut (BATC) 6660A band using the large-format CCD system on the 0.6m Schmidt telescope at the Xinglong Station of the National Astronomical Observatories of China (NAOC). we obtain a final image that is calibrated to an accuracy of 0.02 mag in zero point, and for which we can measure galaxy surface brightness to an accuracy of 0.25 mag at a surface brightness at 27.5 mag arcsec^-2 at 6660A, corresponding to a distance of 22 kpc from the center of the disk. The integrated magnitude of NGC4565 in our filter is m6660=8.99 (R magnitude of 9.1) to a surface brightness of 28 mag arcsec-2. We analyze the faint outer parts of this galaxy using a two-dimensional model comprised of three components: an exponential thin disk, an exponential thick disk, and a power-law halo. A total of 12 parameters are included in our model. We determine the best values of our model parameters via 10,000 random initial values, 3,700 of which converge to final values. The thin disk and thick disk parameters we determine here are consistent with those of previous studies of this galaxy. However, our very deep image permits a better determination of the power law fit to the halo, constraining this power law to be between r^-3.2 and r^-4.0, with a best fit value of r^-3.88. We find the axis ratio of the halo to be 0.44 and its core radius to be 14.4 kpc (for an adopted distance of 14.5 Mpc).Comment: 34 pages, 11 figures, will appear in March 2002 of A

    Carbon Nanostructure-Based Field-Effect Transistors for Label-Free Chemical/Biological Sensors

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    Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has advantages of high sensitivity, low decreased energy consumption and potentially highly miniaturized integration. Owing to their particular structure, excellent electrical properties and high chemical stability, carbon nanotube and graphene based electrical devices have been widely developed for high performance label-free chemical/biological sensors. Here, we review the latest developments of carbon nanostructure-based transistor sensors in ultrasensitive detection of chemical/biological entities, such as poisonous gases, nucleic acids, proteins and cells

    Octyl itaconate enhances VSVΔ51 oncolytic virotherapy by multitarget inhibition of antiviral and inflammatory pathways

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    The presence of heterogeneity in responses to oncolytic virotherapy poses a barrier to clinical effectiveness, as resistance to this treatment can occur through the inhibition of viral spread within the tumor, potentially leading to treatment failures. Here we show that 4-octyl itaconate (4-OI), a chemical derivative of the Krebs cycle-derived metabolite itaconate, enhances oncolytic virotherapy with VSVΔ51 in various models including human and murine resistant cancer cell lines, three-dimensional (3D) patient-derived colon tumoroids and organotypic brain tumor slices. Furthermore, 4-OI in combination with VSVΔ51 improves therapeutic outcomes in a resistant murine colon tumor model. Mechanistically, we find that 4-OI suppresses antiviral immunity in cancer cells through the modification of cysteine residues in MAVS and IKKβ independently of the NRF2/KEAP1 axis. We propose that the combination of a metabolite-derived drug with an oncolytic virus agent can greatly improve anticancer therapeutic outcomes by direct interference with the type I IFN and NF-κB-mediated antiviral responses.</p

    Octyl itaconate enhances VSVΔ51 oncolytic virotherapy by multitarget inhibition of antiviral and inflammatory pathways

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    The presence of heterogeneity in responses to oncolytic virotherapy poses a barrier to clinical effectiveness, as resistance to this treatment can occur through the inhibition of viral spread within the tumor, potentially leading to treatment failures. Here we show that 4-octyl itaconate (4-OI), a chemical derivative of the Krebs cycle-derived metabolite itaconate, enhances oncolytic virotherapy with VSVΔ51 in various models including human and murine resistant cancer cell lines, three-dimensional (3D) patient-derived colon tumoroids and organotypic brain tumor slices. Furthermore, 4-OI in combination with VSVΔ51 improves therapeutic outcomes in a resistant murine colon tumor model. Mechanistically, we find that 4-OI suppresses antiviral immunity in cancer cells through the modification of cysteine residues in MAVS and IKKβ independently of the NRF2/KEAP1 axis. We propose that the combination of a metabolite-derived drug with an oncolytic virus agent can greatly improve anticancer therapeutic outcomes by direct interference with the type I IFN and NF-κB-mediated antiviral responses.</p

    The Impact of Individual Trading on Stock Returns

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    [[sponsorship]]淡江大學[[notice]]待補頁數[[conferencetype]]國際[[conferencetkucampus]]台北校園[[conferencedate]]20120526~20120527[[booktype]]其他[[conferencelocation]]新北市, 臺

    Information Content of Net Buying-Pressure:Evidence from the TXO Market

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    [[sponsorship]]清华大学中国金融研究中心;麻省理工学院斯隆管理学院[[conferencetype]]國際[[conferencedate]]20130710~20130713[[iscallforpapers]]Y[[conferencelocation]]上海, 中

    View Bias towards Ambiguity, Expectile CAPM and the Anomalies ✩,✩✩

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    Information ambiguity introduces view bias. By defining this view bias, we develop a novel reward-risk measurement framework, an extended CAPM a sequence of empirical test procedures to explain asset pricing anomalies. U.S. stock market data (1926-1999) implies a pessimistic view on average for people with rational risk preference; that explains the equity premium puzzle. The extended CAPM still admits a single beta representation. The amount of risk becomes the weighted average of systematic risk and latent risk. The price of risk, or the expected market excess return, is adjusted by view bias. The momentum effect has two alternative explanations within this framework. Either the winner has a low systematic risk but a high latent risk, and the adjusted price of risk is positive; or the winner has a low systematic risk and a low amount of risk (a weighted average of systematic risk and latent risk), but the adjusted price of risk is negative. Post-war U.S. data supports the latter explanation. Keywords
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