المؤلفون: K. Yan, J. Wang, R. Peng, K. Yang, X. Chen, G. Yin, J. Dong, M. Weiss, J. Pu, R. B. Myneni

المصدر: Earth System Science Data, Vol 16, Pp 1601-1622 (2024)

مصطلحات موضوعية: Environmental sciences, GE1-350, Geology, QE1-996.5

الوصف: Leaf area index (LAI) is a crucial parameter for characterizing vegetation canopy structure and energy absorption capacity. The Moderate Resolution Imaging Spectroradiometer (MODIS) LAI has played a significant role in landmark studies due to its clear theoretical basis, extensive historical time series, extensive validation results, and open accessibility. However, MODIS LAI retrievals are calculated independently for each pixel and a specific day, resulting in high noise levels in the time series and limiting its applications in the regions of optical remote sensing. Reprocessing MODIS LAI predominantly relies on temporal information to achieve smoother LAI profiles with little use of spatial information and may easily ignore genuine LAI anomalies. To address these problems, we designed the spatiotemporal information compositing algorithm (STICA) for the reprocessing of MODIS LAI products. This method integrates information from multiple dimensions, including pixel quality information, spatiotemporal correlation, and the original retrieval, thereby enabling both “reprocessing” and “value-added data” with respect to the existing MODIS LAI products, leading to the development of the high-quality LAI (HiQ-LAI) dataset. Compared with ground measurements, HiQ-LAI shows better performance than the original MODIS product with a root-mean-square error (RMSE) or bias decrease from 0.87 or −0.17 to 0.78 or −0.06, respectively. This is due to the improvement of HiQ-LAI with respect to capturing the seasonality in vegetation phenology and reducing abnormal time-series fluctuations. The time-series stability (TSS) index, which represents temporal stability, indicated that the area with smooth LAI time series expanded from 31.8 % (MODIS) to 78.8 % (HiQ) globally, and this improvement is more obvious in equatorial regions where optical remote sensing cannot usually achieve good performance. We found that HiQ-LAI demonstrates superior continuity and consistency compared with raw MODIS LAI from both spatial and temporal perspectives. We anticipate that the global HiQ-LAI time series, generated using the STICA procedure on the Google Earth Engine (GEE) platform, will substantially enhance support for diverse global LAI time-series applications. The 5 km 8 d HiQ-LAI datasets from 2000 to 2022 are available at https://doi.org/10.5281/zenodo.8296768Test (Yan et al., 2023).

وصف الملف: electronic resource

العلاقة: https://essd.copernicus.org/articles/16/1601/2024/essd-16-1601-2024.pdfTest; https://doaj.org/toc/1866-3508Test; https://doaj.org/toc/1866-3516Test

الوصول الحر: https://doaj.org/article/d39d048464a544f1a8b80e05fb172e74Test

المؤلفون: E. J. M. Van Heesch, T. Huiskamp, K. Yan, F. J. C. M. Beckers, H. W. M. Smulders, G. J. J. Winands, R. H. P. Lemmens, P. P. M. Blom, S. Davalos Segura, W. F. L. M. Hoeben, S. V. B. Van Paasen, J. J. Van Oorschot, A. G. A. Bonkestoter, M. L. J. Van Den Brand, M. Hennink, R. W. J. Smulders, A. J. M. Pemen, P. C. T. Van Der Laan

المصدر: Frontiers in Chemistry, Vol 12 (2024)

مصطلحات موضوعية: cold plasma, nanosecond pulses, pulsed processing, plasma processing, VOC, emission control, Chemistry, QD1-999

الوصف: A promising pollution control technology is cold plasma driven chemical processing. The plasma is a pulsed electric gas discharge inside a near atmospheric-pressure-temperature reactor. The system is energized by a continuous stream of very short high-voltage pulses. The exhaust gas to be treated flows through the reactor. The methods applied involve the development of robust cold plasma systems, industrial applications and measuring technologies. Tests of the systems were performed at many industrial sites and involved control of airborne VOC (volatile organic compound) and odor. Electrical, chemical and odor measuring data were collected with state-of-the-art methods. To explain the test data an approximate solution of global reaction kinetics of pulsed plasma chemistry was developed. It involves the Lambert function and, for convenience, a simple approximation of it. The latter shows that the amount of removal, in good approximation, is a function of a single variable. This variable is electric plasma power divided by gas flow divided by input concentration. In the results sections we show that in some cases up to 99% of volatile pollution can be removed at an acceptable energy requirement. In the final sections we look into future efficiency enhancements by implementation of (sub)nanosecond pulsed plasma and solid state high-voltage technology and by integration with catalyst technology.

وصف الملف: electronic resource

العلاقة: https://www.frontiersin.org/articles/10.3389/fchem.2024.1386055/fullTest; https://doaj.org/toc/2296-2646Test

الوصول الحر: https://doaj.org/article/40e3ccd3cc2c496bbc9abd60a7657904Test

المؤلفون: J. Pu, K. Yan, S. Roy, Z. Zhu, M. Rautiainen, Y. Knyazikhin, R. B. Myneni

المصدر: Earth System Science Data, Vol 16, Pp 15-34 (2024)

مصطلحات موضوعية: Environmental sciences, GE1-350, Geology, QE1-996.5

الوصف: Leaf area index (LAI) and fraction of photosynthetically active radiation (FPAR) are critical biophysical parameters for the characterization of terrestrial ecosystems. Long-term global LAI/FPAR products, such as the moderate resolution imaging spectroradiometer (MODIS) and the Visible Infrared Imaging Radiometer Suite (VIIRS), provide the fundamental dataset for accessing vegetation dynamics and studying climate change. However, existing global LAI/FPAR products suffer from several limitations, including spatial–temporal inconsistencies and accuracy issues. Considering these limitations, this study develops a sensor-independent (SI) LAI/FPAR climate data record (CDR) based on Terra-MODIS/Aqua-MODIS/VIIRS LAI/FPAR standard products. The SI LAI/FPAR CDR covers the period from 2000 to 2022, at spatial resolutions of 500 m/5 km/0.05∘, 8 d/bimonthly temporal frequencies and available in sinusoidal and WGS1984 projections. The methodology includes (i) comprehensive analyses of sensor-specific quality assessment variables to select high-quality retrievals, (ii) application of the spatial–temporal tensor (ST-tensor) completion model to extrapolate LAI and FPAR beyond areas with high-quality retrievals, (iii) generation of SI LAI/FPAR CDR in various projections and various spatial and temporal resolutions, and (iv) evaluation of the CDR by direct comparisons with ground data and indirectly through reproducing results of LAI/FPAR trends documented in the literature. This paper provides a comprehensive analysis of each step involved in the generation of the SI LAI/FPAR CDR, as well as evaluation of the ST-tensor completion model. Comparisons of SI LAI (FPAR) CDR with ground truth data suggest an RMSE of 0.84 LAI (0.15 FPAR) units with R2 of 0.72 (0.79), which outperform the standard Terra/Aqua/VIIRS LAI (FPAR) products. The SI LAI/FPAR CDR is characterized by a low time series stability (TSS) value, suggesting a more stable and less noisy dataset than sensor-dependent counterparts. Furthermore, the mean absolute error (MAE) of the CDR is also lower, suggesting that SI LAI/FPAR CDR is comparable in accuracy to high-quality retrievals. LAI/FPAR trend analyses based on the SI LAI/FPAR CDR agree with previous studies, which indirectly provides enhanced capabilities to utilize this CDR for studying vegetation dynamics and climate change. Overall, the integration of multiple satellite data sources and the use of advanced gap filling modeling techniques improve the accuracy of the SI LAI/FPAR CDR, ensuring the reliability of long-term vegetation studies, global carbon cycle modeling, and land policy development for informed decision-making and sustainable environmental management. The SI LAI/FPAR CDR is open access and available under a Creative Commons Attribution 4.0 License at https://doi.org/10.5281/zenodo.8076540Test (Pu et al., 2023a).

وصف الملف: electronic resource

العلاقة: https://essd.copernicus.org/articles/16/15/2024/essd-16-15-2024.pdfTest; https://doaj.org/toc/1866-3508Test; https://doaj.org/toc/1866-3516Test

الوصول الحر: https://doaj.org/article/02575e01efcb4e6196a7bef87580a953Test

المؤلفون: C. ZHANG, K. YAN, L.Z. LIN, Y.M. FANG, X.Y. ZHANG

المصدر: Photosynthetica, Vol 60, Iss 2, Pp 190-199 (2022)

مصطلحات موضوعية: biomass, fruit development, photosynthesis, pruning, source-sink relationship, Botany, QK1-989

الوصف: The formation of economic yield and fruit quality of Roxburgh rose (Rosa roxburghii Tratt.) depends essentially on its source-sink interaction. Thus, a pruning experiment was conducted to assess the effects of source-sink regulation on photosynthetic physiology and fruit yield of Roxburgh rose, which was of great significance to production. Cutting off vegetative branches reduced physiological fruit loss and malformed fruits but increased single fruit quality and yield. Results revealed that the stomatal characteristics, the composition of mesophyll tissue, and photosynthesis of leaves on reproductive branches were significantly affected by the ratio of the vegetative and reproductive shoots. Our data indicated that the source-sink ratio could reflect the balance between vegetative growth and reproductive growth of the tree during the whole fruit period. Fruit tree pruning had guiding significance for improving the fruit yield of Roxburgh rose.

وصف الملف: electronic resource

العلاقة: https://ps.ueb.cas.cz/artkey/phs-202202-0004_effects-of-source-sink-alteration-by-pruning-on-physiological-parameters-and-fruit-production-of-rosa-roxburghi.phpTest; https://doaj.org/toc/0300-3604Test; https://doaj.org/toc/1573-9058Test

الوصول الحر: https://doaj.org/article/db7abb2b59bf4cdc83193d38691f4014Test

المؤلفون: A.W. Aldeen, Z.W. Chen, I.A. Disher, Y. Zhu, K. Yan

المصدر: Journal of Materials Research and Technology, Vol 17, Iss , Pp 2038-2046 (2022)

مصطلحات موضوعية: N36 zirconium alloy, Aging, SPPs, Growth kinetics, Mining engineering. Metallurgy, TN1-997

الوصف: Analyzing the diffusion kinetics behavior that leads to precipitates formation can assist in understanding the properties of Zr alloy materials. In this study, coarsening growth kinetics of precipitates in N36 zirconium alloy with Nb dominant are experimentally calculated during the isothermal and isochronal aging process (580 °C–700 °C, 0.5–30 h respectively). Microstructure observation and the second phase particles (SPPs) have been investigated and numerically extracted through several processes, including the use of an optical microscope (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), in addition to image software tools. Conclusions confirm that as the temperature or aging period increases, the SPPs begin to lose fine and linear distribution properties ranging from α-plate grain boundary to the random distributions. Moreover, the small particles dissolve, whereas the large ones grow, accurately pursuing the Ostwald ripening property. Besides, most SPPs are found to be in the form of Zr(Nb, Fe)2, and some of them are (Zr,Nb)2Fe. The activation energy of kinetic growth of precipitates has been experimentally calculated using Kahlwiet second-order kinetics and found to be 206 kJ/mol. Compared to other documented Zr-alloy series, we have noticed that the different types of SPPs and the Nb element content in most contribute greatly to the slow diffusion rate, explaining the higher value in the activation energy of the precipitates growth process.

وصف الملف: electronic resource

العلاقة: http://www.sciencedirect.com/science/article/pii/S2238785422001429Test; https://doaj.org/toc/2238-7854Test

الوصول الحر: https://doaj.org/article/8ed5c469cba74e33a42315c139c49030Test

المؤلفون: A.W. Aldeen, Z.W. Chen, I.A. Disher, Y. Zhu, K. Yan

المصدر: Journal of Materials Research and Technology, Vol 19, Iss , Pp 5069- (2022)

مصطلحات موضوعية: Mining engineering. Metallurgy, TN1-997

وصف الملف: electronic resource

العلاقة: http://www.sciencedirect.com/science/article/pii/S2238785422011152Test; https://doaj.org/toc/2238-7854Test

الوصول الحر: https://doaj.org/article/df46bbf44f8542b8bb460b666afce606Test

المؤلفون: D. Chicherin, J. M. Henn, E. Sokatchev, K. Yan

المصدر: Journal of High Energy Physics, Vol 2021, Iss 2, Pp 1-35 (2021)

مصطلحات موضوعية: Conformal Field Theory, Perturbative QCD, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798

الوصف: Abstract We present a method for calculating event shapes in QCD based on correlation functions of conserved currents. The method has been previously applied to the maximally supersymmetric Yang-Mills theory, but we demonstrate that supersymmetry is not essential. As a proof of concept, we consider the simplest example of a charge-charge correlation at one loop (leading order). We compute the correlation function of four electromagnetic currents and explain in detail the steps needed to extract the event shape from it. The result is compared to the standard amplitude calculation. The explicit four-point correlation function may also be of interest for the CFT community.

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/1029-8479Test

الوصول الحر: https://doaj.org/article/836e5b3798f34e2899a4d50be71ce2cdTest

المؤلفون: D. Medranda, J. Borowiec, Xiao Zhang, S. Wang, K. Yan, J. Zhang, Y. He, S. Ivaturi, F. S. Boi

المصدر: Royal Society Open Science, Vol 5, Iss 1 (2018)

مصطلحات موضوعية: ferromagnetic, sulfur, carbon onions, Science

الوصف: A key challenge in the fabrication of ferromagnetically filled carbon nano-onions (CNOs) is the control of their thickness, dimensions and electric properties. Up to now literature works have mainly focused on the encapsulation of different types of ferromagnetic materials including α-Fe, Fe3C, Co, FeCo, FePd3 and others within CNOs. However, no report has yet shown a suitable method for controlling both the number of shells, diameter and electric properties of the produced CNOs. Here, we demonstrate an advanced chemical vapour deposition approach in which the use of small quantities of sulfur during the pyrolysis of ferrocene allows for the control of (i) the diameter of the CNOs, (ii) the number of shells and (iii) the electric properties. We demonstrate the morphological, structural, electric and magnetic properties of these new types of CNOs by using SEM, XRD, TEM, HRTEM, EIS and VSM techniques.

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2054-5703Test

الوصول الحر: https://doaj.org/article/426aa25d50b043d4a350e1e79e4c3c58Test

المؤلفون: G. di Baldassarre, K. Yan, MD. R. Ferdous, L. Brandimarte

المصدر: Proceedings of the International Association of Hydrological Sciences, Vol 364, Pp 188-191 (2014)

مصطلحات موضوعية: Environmental sciences, GE1-350, Geology, QE1-996.5

الوصف: In Bangladesh, socio-economic and hydrological processes are both extremely dynamic and inter-related. Human population patterns are often explained as a response, or adaptation strategy, to physical events, e.g. flooding, salt-water intrusion, and erosion. Meanwhile, these physical processes are exacerbated, or mitigated, by diverse human interventions, e.g. river diversion, levees and polders. In this context, this paper describes an attempt to explore the complex interplay between floods and societies in Bangladeshi floodplains. In particular, we performed a spatially-distributed analysis of the interactions between the dynamics of human settlements and flood inundation patterns. To this end, we used flooding simulation results from inundation modelling, LISFLOOD-FP, as well as global datasets of population distribution data, such as the Gridded Population of the World (20 years, from 1990 to 2010) and HYDE datasets (310 years, from 1700 to 2010). The outcomes of this work highlight the behaviour of Bangladeshi floodplains as complex human–water systems and indicate the need to go beyond the traditional narratives based on one-way cause–effects, e.g. climate change leading to migrations.

وصف الملف: electronic resource

العلاقة: https://www.proc-iahs.net/364/188/2014/piahs-364-188-2014.pdfTest; https://doaj.org/toc/2199-8981Test; https://doaj.org/toc/2199-899XTest

الوصول الحر: https://doaj.org/article/4f06f277cfd04cd7b40bb5ed67e954e6Test

المؤلفون: W. Zhang, Y. Chen, K. Yan, G. Yan, G. Zhou

المصدر: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXIX-B3, Pp 373-378 (2012)

مصطلحات موضوعية: Technology, Engineering (General). Civil engineering (General), TA1-2040, Applied optics. Photonics, TA1501-1820

الوصف: Airborne LiDAR data and optical imagery are two datasets used for 3D building reconstruction. By study of the complementarities of these two datasets, we proposed a primitive-based 3D building reconstruction method, which can use LiDAR data and optical imagery at the same time. The proposed method comprises following steps: (1) recognize primitives from LiDAR point cloud and roughly measure primitives’ parameters as initial values, and (2) select primitives' features on the imagery, and (3) optimize primitives' parameters by the constraints of LiDAR point cloud and imagery, and (4) represent 3D building model by these optimized primitives. Compared with other model-based or CSG-based methods, the proposed method has some advantages. It is simpler, because it only uses the most straightforward features, i.e. planes of LiDAR point cloud and points of optical imagery. And it can tightly integrate LiDAR point cloud and optical imagery, that is to say, all primitives' parameters are optimized with all constraints in one step. Recently, an ISPRS Test Project on Urban Classification and 3D Building Reconstruction was launched, two datasets both with airborne LiDAR data and images are provided. The proposed method was applied to Area 3 of Dataset 1 Vaihingen, in which there are some buildings with plane roofs or gable roofs. The organizer of this test project evaluated the submitted reconstructed 3D model using reference data. The result shows the feasibility of the proposed 3D building reconstruction method.

وصف الملف: electronic resource

العلاقة: https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XXXIX-B3/373/2012/isprsarchives-XXXIX-B3-373-2012.pdfTest; https://doaj.org/toc/1682-1750Test; https://doaj.org/toc/2194-9034Test

الوصول الحر: https://doaj.org/article/6a06a179de084295b467c2391a1edf3fTest