| 991. |
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| 992. |
- Wang, Z. H., et al.
(författare)
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Investigation on elemental mercury oxidation mechanism by non-thermal plasma treatment
- 2010
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820. ; 91:11, s. 1395-1400
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Tidskriftsartikel (refereegranskat)abstract
- Converting elemental mercury into divalent compound is one of the most important steps for mercury abatement from coal fired flue gas. The oxidation of elemental mercury was investigated in this paper using dielectric barrier discharge (DBD) non-thermal plasma (NTP) technology at room temperature. Effects of different flue gas components like oxygen, moisture, HCl, NO and SO2 were investigated. Results indicate that active radicals including O, O-3 and OH all contribute to the oxidation of elemental mercury. Under the conditions of 5% O-2 in the simulated flue gas, about 90.2% of Hg-0 was observed to be oxidized at 3.68 kV discharge voltage. The increase of discharge voltage, O-2 level and H2O content can all improve the oxidation rate, individually. With O-2 and H2O both existed, there is an optimal moisture level for the mercury oxidation during the NTP treatment. In this test, the observed optimal moisture level was around 0.74% by volume. Hydrogen chloride can promote the oxidation of mercury due to chlorine atoms produced in the plasma process. Both NO and SO2 have inhibitory effects on mercury oxidation, which can be attributed to their competitive consumption of O-3 and O. (c) 2010 Elsevier By. All rights reserved.
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| 993. |
- Widmer, Joerg, et al.
(författare)
-
Enablers toward 6G positioning and sensing
- 2024
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Ingår i: Positioning and Location-based Analytics in 5G and Beyond. - 9781119911463 ; , s. 75-97
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter provides the reader with an overview of three major trends toward 6G, namely integrated sensing and communication, the ability to control radio wave propagation in the environment thanks to reconfigurable intelligent surfaces, and advances in model-based and model-free signal processing. This list of trends is by no means exhaustive, but only aims to highlight the tremendous potential for research and innovation toward 6G positioning.
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| 994. |
- Wiedensohler, A., et al.
(författare)
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Mobility particle size spectrometers: harmonization of technical standards and data structure to facilitate high quality long-term observations of atmospheric particle number size distributions
- 2012
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 5:3, s. 657-685
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Tidskriftsartikel (refereegranskat)abstract
- Mobility particle size spectrometers often referred to as DMPS (Differential Mobility Particle Sizers) or SMPS (Scanning Mobility Particle Sizers) have found a wide range of applications in atmospheric aerosol research. However, comparability of measurements conducted world-wide is hampered by lack of generally accepted technical standards and guidelines with respect to the instrumental set-up, measurement mode, data evaluation as well as quality control. Technical standards were developed for a minimum requirement of mobility size spectrometry to perform long-term atmospheric aerosol measurements. Technical recommendations include continuous monitoring of flow rates, temperature, pressure, and relative humidity for the sheath and sample air in the differential mobility analyzer. We compared commercial and custom-made inversion routines to calculate the particle number size distributions from the measured electrical mobility distribution. All inversion routines are comparable within few per cent uncertainty for a given set of raw data. Furthermore, this work summarizes the results from several instrument intercomparison workshops conducted within the European infrastructure project EUSAAR (European Supersites for Atmospheric Aerosol Research) and ACTRIS (Aerosols, Clouds, and Trace gases Research InfraStructure Network) to determine present uncertainties especially of custom-built mobility particle size spectrometers. Under controlled laboratory conditions, the particle number size distributions from 20 to 200 nm determined by mobility particle size spectrometers of different design are within an uncertainty range of around +/- 10% after correcting internal particle losses, while below and above this size range the discrepancies increased. For particles larger than 200 nm, the uncertainty range increased to 30%, which could not be explained. The network reference mobility spectrometers with identical design agreed within +/- 4% in the peak particle number concentration when all settings were done carefully. The consistency of these reference instruments to the total particle number concentration was demonstrated to be less than 5%. Additionally, a new data structure for particle number size distributions was introduced to store and disseminate the data at EMEP (European Monitoring and Evaluation Program). This structure contains three levels: raw data, processed data, and final particle size distributions. Importantly, we recommend reporting raw measurements including all relevant instrument parameters as well as a complete documentation on all data transformation and correction steps. These technical and data structure standards aim to enhance the quality of long-term size distribution measurements, their comparability between different networks and sites, and their transparency and traceability back to raw data.
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| 995. |
- Wijesooriya, K, et al.
(författare)
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Polarization measurements in neutral pion photoproduction
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:3
-
Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the recoil proton polarization for the H-1((γ) over right arrow,(p) over right arrow)pi(0) reaction for theta(c.m.)(pi) = 60degrees-135degrees and for photon energies up to 4.1 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. Various theoretical models are compared with the results. No evidence for hadron helicity conservation is observed. Models that employ factorization are not favored. It appears from the strong angular dependence of the induced polarization at photon energies of 2.5 and 3.1 GeV that a relatively high spin resonance or background amplitude might exist in this energy region.
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| 996. |
- Wu, M., et al.
(författare)
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Identification of the nuclear localization signal of SALL4B, a stem cell transcription factor
- 2014
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Ingår i: Cell Cycle. - : Informa UK Limited. - 1538-4101 .- 1551-4005. ; 13:9, s. 1456-1462
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Tidskriftsartikel (refereegranskat)abstract
- SALL4B plays a critical role in maintaining the pluripotency of embryonic stem cells and hematopoietic stem cells. SALL4B primarily functions as a transcription factor, and, thus, its nuclear localization is paramount to its biological activities. To understand the structural basis by which SALL4B was transported and retained in the nucleus, we made a series of SALL4B constructs with deletions or point mutations. We found that K64R mutation resulted in a random distribution of SALL4B within the cell. An analysis of neighboring amino acid sequences revealed that (KRLR67)-K-64 in SALL4B matches exactly with the canonical nuclear localization signal (K-K/R-x-K/R). SALL4B fragment (a. a. 50-109) that contained KRLR was sufficient for targeting GFP-tagged SALL4B to the nucleus, whereas K64R mutation led to a random distribution of GFP-SALL4B signal within the cell. We further demonstrated that the nuclear localization was essential for transactivating luciferase reporter gene driven by OCT4 promoter, a known transcriptional target of SALL4B. Therefore, our study identifies the KRLR sequence as a bona fide nuclear localization signal for SALL4B.
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| 997. |
- Wu, X. -S, et al.
(författare)
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The Morphology of the Topside Martian Ionosphere : Implications on Bulk Ion Flow
- 2019
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Ingår i: Journal of Geophysical Research - Planets. - 2169-9097 .- 2169-9100. ; 124:3, s. 734-751
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Tidskriftsartikel (refereegranskat)abstract
- AbstractPrior to the Mars Atmosphere and Volatile Evolution mission, the only information on the composition of the Martian ionosphere came from the Viking Retarding Potential Analyzer data, revealing the presence of substantial ion outflow on the dayside of Mars. Extensive measurements made by the Mars Atmosphere and Volatile Evolution Neutral Gas and Ion Mass Spectrometer allow us to examine the morphology of the Martian ionosphere not only in unprecedented detail but also on both the dayside and the nightside of the planet. Above 300 km, various ionospheric species present a roughly constant density scale height around 100 km on the dayside and 180 km on the nightside. An evaluation of the ion force balance, appropriate for regions with near‐horizontal magnetic field lines, suggests the presence of supersonic ion outflow predominantly driven by the ambient magnetic pressure, with characteristic dayside and nightside flow velocities of 4 and 20 km/s, respectively, both referred to an altitude of 500 km. The corresponding total ion outflow rates are estimated to be 5 × 1025 s−1 on the dayside and 1 × 1025 s−1 on the nightside. The data also indicate a prominent variation with magnetic field orientation in that the ion distribution over regions with near‐vertical field lines tends to be more extended on the dayside but more concentrated on the nightside, as compared to regions with near‐horizontal field lines. These observations should have important implications on the pattern of ion dynamics in the vicinity of Mars.
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| 998. |
- Xiang, Z., et al.
(författare)
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Computing Power Allocation and Traffic Scheduling for Edge Service Provisioning
- 2020
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Ingår i: Proceedings - 2020 IEEE 13th International Conference on Web Services, ICWS 2020. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781728187860 ; , s. 394-403
-
Konferensbidrag (refereegranskat)abstract
- The increasing number of mobile web services makes it convenient for users to complete complex tasks on their mobile devices. However, the latency brought by unstable wireless networks and the computation failures caused by constrained resources limit the development of mobile computing. A popular approach to solve this problem is to establish a mobile service provisioning system based on the mobile edge computing (MEC) paradigm, in which the latency can be reduced and the computation can be offloaded with the help of services deployed on nearby edge servers. However, as the edge servers are resource-limited, we should be more careful in allocating the edge resource to services, as well as designing the traffic scheduling strategy. In this paper, we investigate the edge-cloud cooperation mechanism in service provisioning as well as the billing model of it. To minimize the average service response time and make the expense acceptable, we model and formulate the performance-cost service provisioning problem as a joint optimization problem whose decision variables are the resource allocation strategy and traffic scheduling strategy. Then we propose an efficient online algorithm, called PCA- CATS, to decompose this problem into two individual subproblems. We conduct a series of experiments to evaluate the performance of our approach. The results show that PCA- CATS can easily balance the performance and expense with a factor V, and can reduce up to 53.3 % service response time as compared with the baselines.
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| 999. |
- Xiao, Z., et al.
(författare)
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A learning-based view extrapolation method for axial super-resolution
- 2021
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Ingår i: Neurocomputing. - : Elsevier B.V.. - 0925-2312 .- 1872-8286. ; 455, s. 229-241
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Tidskriftsartikel (refereegranskat)abstract
- Axial light field resolution refers to the ability to distinguish features at different depths by refocusing. The axial refocusing precision corresponds to the minimum distance in the axial direction between two distinguishable refocusing planes. High refocusing precision can be essential for some light field applications like microscopy. In this paper, we propose a learning-based method to extrapolate novel views from axial volumes of sheared epipolar plane images (EPIs). As extended numerical aperture (NA) in classical imaging, the extrapolated light field gives re-focused images with a shallower depth of field (DOF), leading to more accurate refocusing results. Most importantly, the proposed approach does not need accurate depth estimation. Experimental results with both synthetic and real light fields show that the method not only works well for light fields with small baselines as those captured by plenoptic cameras (especially for the plenoptic 1.0 cameras), but also applies to light fields with larger baselines. © 2021 Elsevier B.V.
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| 1000. |
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