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1دورية أكاديمية
المؤلفون: Shudi Yang, Tonghui Zhang, Zheng-an Yao
المصدر: Entropy, Vol 26, Iss 6, p 455 (2024)
مصطلحات موضوعية: linear code, weight distribution, Walsh transform, plateaued function, Science, Astrophysics, QB460-466, Physics, QC1-999
الوصف: Linear codes are the most important family of codes in cryptography and coding theory. Some codes only have a few weights and are widely used in many areas, such as authentication codes, secret sharing schemes and strongly regular graphs. By setting p≡1(mod4), we constructed an infinite family of linear codes using two distinct weakly regular unbalanced (and balanced) plateaued functions with index (p−1)/2. Their weight distributions were completely determined by applying exponential sums and Walsh transform. As a result, most of our constructed codes have a few nonzero weights and are minimal.
وصف الملف: electronic resource
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2دورية أكاديمية
المؤلفون: Shudi Yang, Tonghui Zhang, Ping Li
المصدر: Entropy, Vol 25, Iss 2, p 369 (2023)
مصطلحات موضوعية: linear code, weight distribution, Walsh transform, plateaued balanced function, Science, Astrophysics, QB460-466, Physics, QC1-999
الوصف: Linear codes with a few weights have been extensively studied due to their wide applications in secret sharing schemes, strongly regular graphs, association schemes, and authentication codes. In this paper, we choose the defining sets from two distinct weakly regular plateaued balanced functions, based on a generic construction of linear codes. Then we construct a family of linear codes with at most five nonzero weights. Their minimality is also examined and the result shows that our codes are helpful in secret sharing schemes.
وصف الملف: electronic resource
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3دورية أكاديمية
المؤلفون: Zhaoquan He, Xue Shang, Tonghui Zhang
المصدر: Forests, Vol 12, Iss 12, p 1754 (2021)
مصطلحات موضوعية: forest ecosystem, PSR model, land security, natural-socio-economic-ecological systems, Yan’an, Plant ecology, QK900-989
الوصف: Forest landscape restoration and ecosystem of Loess Plateau have enhanced prominently, since the policy implementation (1999) of the Grain for Green Project in China. Land ecological security (LES) performs an extremely critical function for protecting vulnerable land resources and sustaining forest ecosystem stability. Predecessors’ studies substantially concentrate on biophysical and meteorologic variables using numerous grounded methodologies, little research has been launched on systematic natural-socio-economic-ecological relationships and how these contributions and regulations for LES evaluation. Here, pressure-state-response (PSR) model was used to establish the evaluation system of LES in regional-scale, and LES was classified into five levels measured by ecological security index (S), including high (S ≥ 0.75), medium−high (0.65 ≤ S < 0.75), medium (0.55 ≤ S < 0.65), medium−low (0.45 ≤ S < 0.55), and low (S < 0.45) level, for systematically analyzing its spatiotemporal distribution characteristic and response mechanism to explanatory variables in Yan’an, northwest China, from 2000 to 2018. The results demonstrated that: (1) LES status was mainly characterized by medium−high level and medium level, and maintained profound stability. (2) zone with medium−high LES level was mainly concentrated in western and southern regions, continuously expanding to northeast regions, and possessed the largest territorial area, accounting for 37.22–46.27% of the total area in Yan’an. (3) LES was primarily susceptible to normalized differential vegetation index, vegetation coverage, and land surface temperature with their optimal impacting thresholds of 0.20–0.64, 0.20–0.55, and 11.20–13.00 °C, respectively. (4) Normalized differential vegetation index and vegetation coverage had a significant synergistic effect upon LES based on their interactive explanation rate of 31% and had significant variation consistency (positive and negative) with LES, which were powerfully suggested to signal the intensification of the regional eco-security level in the persistent eco-greening process.
وصف الملف: electronic resource
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4دورية أكاديمية
المؤلفون: Fenfen Liu, Tonghui Zhang, Haibin Ye, Shilin Tang
المصدر: Water, Vol 13, Iss 4, p 435 (2021)
مصطلحات موضوعية: suspended sediment concentration, symbolic regression, Landsat, sand excavation, Hydraulic engineering, TC1-978, Water supply for domestic and industrial purposes, TD201-500
الوصف: The Hong Kong-Zhuhai-Macau Bridge crosses the Pearl River Estuary and is the largest bridge and tunnel project in the world. During the construction period of this project, the excessive suspended sediment was found in the construction region. The suspended sediment generated by sand excavation in the upstream was assumed to have a significant impact on the suspended sediment in the tunnel region. In this study, we assessed the impact of upstream sand excavation on the suspended sediment in the Hong Kong-Zhuhai-Macau Bridge construction area using Landsat OLI, ETM+, and TM data. Regional suspended sediment algorithms were developed for Landsat using a symbolic regression method based on data from in situ measurements in the study area from 2003 to 2014. A band shift was conducted on the remote sensing reflectance data from Landsat ETM+ and OLI to produce a time series of the suspended sediment concentrations that was internally consistent with that of the Landsat TM data. The suspended sediment distribution was extracted and used to compare under two different conditions, with and without sand excavation. The correlations of the time series of the suspended sediment concentrations in different regions in the surrounding waters, including the correlations between the construction regions and the sand excavation regions, were calculated. Our results indicated that the sand excavation north of the Pearl River Estuary had a limited impact on the surface suspended sediment concentrations in the Hong Kong-Zhuhai-Macau Bridge tunnel area.
وصف الملف: electronic resource
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5دورية أكاديمية
المؤلفون: Zhaoquan He, Xue Shang, Tonghui Zhang
المصدر: Applied Sciences, Vol 10, Iss 1, p 402 (2020)
مصطلحات موضوعية: water resources, surface mulching, water saving potential, micro-spray irrigation, economic profit, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
الوصف: Water shortage threatens agricultural sustainability in Horqin Sandy Land, northeast China. To explore the effects of various surface mulching patterns with micro-spray irrigation on the yield, water consumption (ETc), and water-saving potential of maize (Zea mays L.), we used three treatments: straw mulching (JG), organic fertilizer mulching (NF), and no mulching (WG; control). In each treatment, plants were supplied with 500 mm of total water (irrigation plus precipitation) during the entire growing season and were irrigated with the amount of total water supply minus precipitation. Yield and water use efficiency (WUE) showed a significant negative correlation with water saving potential per unit yield (Py) and water saving potential per unit area (Sp), which were also consistent with their relationships in the function model. Meanwhile, a remarkably positive correlation occurred between yield, WUE, and net economic profit, respectively. The JG treatment, which was mainly affected by light and temperature production potential (Yc), grain yield, and ETc, showed the lowest Py (0.16 m3 kg−1) and Sp (2572.31 m3 hm−2), and the maximum increase in yield, WUE, and net economic profit, extending to 16,178.40 kg hm−2, 3.25 kg m−3, 17,610.09 yuan hm−2, respectively, which were significantly higher than those in NF and WG, (p y and Sp, which were together responsible for lower WUE.
وصف الملف: electronic resource
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6دورية أكاديمية
المؤلفون: Zhaoquan He, Tonghui Zhang, Xinping Liu, Xue Shang
المصدر: Agronomy, Vol 8, Iss 10, p 221 (2018)
مصطلحات موضوعية: ridge-furrow planting systems, evaportranspiration, crop coefficiency, yield, water use efficiencies, Agriculture
الوصف: Water scarcity threatens the sustainability of irrigated agriculture in semi-arid regions, and ridge-furrow planting systems (RFPS) can be a prospective rainwater harvesting approach. In this study, we aimed to develop a promising water-saving strategy to boost maize productivity and water use efficiency (WUE). In 2017, we carried out a field experiment to study the effects of various RFPS with multiple irrigation levels on the yield-water relationship of maize (Zea mays L.). Eleven treatments were set up: RFPS with film mulching on both ridges and furrows and without water supply after seed emergence, abbreviated as QF; RFPS with film mulching on continuous ridges, abbreviated as MD, including SMD, MMD, and LMD (S, M, and L—three water supply (irrigation plus precipitation) levels of 650 mm, 500 mm, and 350 mm during the whole growing season); RFPS without film mulching, abbreviated as DD, including SDD, MDD, and LDD; conventional flat planting with no film mulching, abbreviated as GG, including SGG, MGG, and LGG; localized full irrigation (actual amount of irrigation excessively exceeding the quantity needed), abbreviated as NM. A positive linear relationship (R2 = 0.95–1), a quadratic curve, and a negative linear relationship were observed between the irrigation water level and actual crop evapotranspiration (ETc), grain yield, and WUE, respectively. The ETc of QF (292 mm) was substantially lower than that of the other treatments (p < 0.01), saving 649 mm of irrigation water and increasing the yield by 2.24% compared with those of NM. Meanwhile, the WUE and irrigation water use efficiency (IWUE) of QF reached maximums of 6.3 and 47.36 kg m−3, respectively, which were significantly higher than those of other treatments (p < 0.001). The results showed that planting in an RFPS with film mulching on both ridges and furrows (a ridge-to-furrow ratio of 50:30, with a 38 mm irrigation level) is suitable for maize to obtain high yield and reduce irrigation water use significantly.
وصف الملف: electronic resource
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7دورية أكاديمية
المؤلفون: Jie Lian, Xueyong Zhao, Xin Li, Tonghui Zhang, Shaokun Wang, Yongqing Luo, Yangchun Zhu, Jing Feng
المصدر: Sustainability, Vol 9, Iss 2, p 211 (2017)
مصطلحات موضوعية: MODIS Normalized Difference Vegetation Index (NDVI), desertification control, farming, sustainable restoration, path analysis, sustainable development goals (SDGs), Environmental effects of industries and plants, TD194-195, Renewable energy sources, TJ807-830, Environmental sciences, GE1-350
الوصف: Vegetation dynamics are an important topic in the field of global environment change, which is of great significance to monitor temporal–spatial variability of desertification at regional or global scales. Following the reported desertification reversion in the late 1990s in the Horqin Sandy Land, an issue was concerned for desertification control by decreased water availability. To detect the desertification process, MODIS Normalized Difference Vegetation Index (NDVI) sequences were investigated to analyze the effect on vegetation over the 2000–2015 growing season. Results showed that: (1) NDVI sequences exhibited a positive trend in most of the significant pixels (19.1%–44.7% of the total), particularly in the southeastern part of Horqin, while showing a negative trend of 2.2%–4.3%; (2) NDVI was weakly related to precipitation since 2000, because intensified anthropogenic activities have obscured the impacts of climate variables, with a rapid decrease in grassland, and increase in cropland and woodland; and (3) the improved NDVI was interpreted by expanding cropland and excessive groundwater irrigation, according to the positive effect of grain yield on NDVI all over the Horqin area. For persistent desertification reversion, a land use strategy should be more adaptive to the carrying capacity in this agro-pastoral transitional zone, particularly with respect to water capacity.
العلاقة: http://www.mdpi.com/2071-1050/9/2/211Test; https://doaj.org/toc/2071-1050Test; https://doaj.org/article/92333b5b176945fdbaee01ac8ee5281aTest
الإتاحة: https://doi.org/10.3390/su9020211Test
https://doaj.org/article/92333b5b176945fdbaee01ac8ee5281aTest -
8
المؤلفون: Tonghui Zhang, Shilin Tang, Fenfen Liu, Haibin Ye
المصدر: Water, Vol 13, Iss 435, p 435 (2021)
Water
Volume 13
Issue 4مصطلحات موضوعية: lcsh:Hydraulic engineering, 010504 meteorology & atmospheric sciences, Geography, Planning and Development, Remote sensing reflectance, 0211 other engineering and technologies, 02 engineering and technology, Aquatic Science, 01 natural sciences, Biochemistry, suspended sediment concentration, lcsh:Water supply for domestic and industrial purposes, lcsh:TC1-978, sand excavation, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Water Science and Technology, Hydrology, geography, lcsh:TD201-500, geography.geographical_feature_category, Sediment, Excavation, Estuary, Satellite remote sensing, Environmental science, symbolic regression, Landsat
الوصف: The Hong Kong-Zhuhai-Macau Bridge crosses the Pearl River Estuary and is the largest bridge and tunnel project in the world. During the construction period of this project, the excessive suspended sediment was found in the construction region. The suspended sediment generated by sand excavation in the upstream was assumed to have a significant impact on the suspended sediment in the tunnel region. In this study, we assessed the impact of upstream sand excavation on the suspended sediment in the Hong Kong-Zhuhai-Macau Bridge construction area using Landsat OLI, ETM+, and TM data. Regional suspended sediment algorithms were developed for Landsat using a symbolic regression method based on data from in situ measurements in the study area from 2003 to 2014. A band shift was conducted on the remote sensing reflectance data from Landsat ETM+ and OLI to produce a time series of the suspended sediment concentrations that was internally consistent with that of the Landsat TM data. The suspended sediment distribution was extracted and used to compare under two different conditions, with and without sand excavation. The correlations of the time series of the suspended sediment concentrations in different regions in the surrounding waters, including the correlations between the construction regions and the sand excavation regions, were calculated. Our results indicated that the sand excavation north of the Pearl River Estuary had a limited impact on the surface suspended sediment concentrations in the Hong Kong-Zhuhai-Macau Bridge tunnel area.
وصف الملف: application/pdf
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fb8ca4c23a5ee80aa6e9d7db36cbebf4Test
https://www.mdpi.com/2073-4441/13/4/435Test -
9
المؤلفون: Xue Shang, Tonghui Zhang, Xinping Liu, Zhaoquan He
المصدر: Agronomy, Vol 8, Iss 10, p 221 (2018)
Agronomy
Volume 8
Issue 10مصطلحات موضوعية: 0106 biological sciences, Irrigation, Field experiment, water use efficiencies, Growing season, Water supply, ridge-furrow planting systems, 01 natural sciences, Rainwater harvesting, lcsh:Agriculture, Water-use efficiency, Mathematics, business.industry, lcsh:S, Sowing, 04 agricultural and veterinary sciences, yield, Agronomy, crop coefficiency, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, evaportranspiration, business, Agronomy and Crop Science, Mulch, 010606 plant biology & botany
الوصف: Water scarcity threatens the sustainability of irrigated agriculture in semi-arid regions, and ridge-furrow planting systems (RFPS) can be a prospective rainwater harvesting approach. In this study, we aimed to develop a promising water-saving strategy to boost maize productivity and water use efficiency (WUE). In 2017, we carried out a field experiment to study the effects of various RFPS with multiple irrigation levels on the yield-water relationship of maize (Zea mays L.). Eleven treatments were set up: RFPS with film mulching on both ridges and furrows and without water supply after seed emergence, abbreviated as QF
RFPS with film mulching on continuous ridges, abbreviated as MD, including SMD, MMD, and LMD (S, M, and L&mdash
three water supply (irrigation plus precipitation) levels of 650 mm, 500 mm, and 350 mm during the whole growing season)
RFPS without film mulching, abbreviated as DD, including SDD, MDD, and LDD
conventional flat planting with no film mulching, abbreviated as GG, including SGG, MGG, and LGG
localized full irrigation (actual amount of irrigation excessively exceeding the quantity needed), abbreviated as NM. A positive linear relationship (R2 = 0.95&ndash
1), a quadratic curve, and a negative linear relationship were observed between the irrigation water level and actual crop evapotranspiration (ETc), grain yield, and WUE, respectively. The ETc of QF (292 mm) was substantially lower than that of the other treatments (p <
0.01), saving 649 mm of irrigation water and increasing the yield by 2.24% compared with those of NM. Meanwhile, the WUE and irrigation water use efficiency (IWUE) of QF reached maximums of 6.3 and 47.36 kg m&minus
3, respectively, which were significantly higher than those of other treatments (p <
0.001). The results showed that planting in an RFPS with film mulching on both ridges and furrows (a ridge-to-furrow ratio of 50:30, with a 38 mm irrigation level) is suitable for maize to obtain high yield and reduce irrigation water use significantly.وصف الملف: application/pdf
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ab6f2f96ed162d5ada148ea391d2588bTest
http://www.mdpi.com/2073-4395/8/10/221Test -
10
المؤلفون: Shaokun Wang, Luo Yongqing, Tonghui Zhang, Yangchun Zhu, Jing Feng, Xin Li, Zhao Xueyong, Jie Lian
المصدر: Sustainability, Vol 9, Iss 2, p 211 (2017)
Sustainability; Volume 9; Issue 2; Pages: 211مصطلحات موضوعية: 010504 meteorology & atmospheric sciences, media_common.quotation_subject, Geography, Planning and Development, MODIS Normalized Difference Vegetation Index (NDVI), Growing season, TJ807-830, Soil science, Woodland, 010501 environmental sciences, Management, Monitoring, Policy and Law, TD194-195, 01 natural sciences, Normalized Difference Vegetation Index, Grassland, farming, Renewable energy sources, desertification control, sustainable development goals (SDGs), path analysis, GE1-350, 0105 earth and related environmental sciences, media_common, geography, geography.geographical_feature_category, Land use, Environmental effects of industries and plants, Renewable Energy, Sustainability and the Environment, sustainable restoration, Vegetation, Environmental sciences, Trend analysis, Desertification, Environmental science, Physical geography
الوصف: Vegetation dynamics are an important topic in the field of global environment change, which is of great significance to monitor temporal–spatial variability of desertification at regional or global scales. Following the reported desertification reversion in the late 1990s in the Horqin Sandy Land, an issue was concerned for desertification control by decreased water availability. To detect the desertification process, MODIS Normalized Difference Vegetation Index (NDVI) sequences were investigated to analyze the effect on vegetation over the 2000–2015 growing season. Results showed that: (1) NDVI sequences exhibited a positive trend in most of the significant pixels (19.1%–44.7% of the total), particularly in the southeastern part of Horqin, while showing a negative trend of 2.2%–4.3%; (2) NDVI was weakly related to precipitation since 2000, because intensified anthropogenic activities have obscured the impacts of climate variables, with a rapid decrease in grassland, and increase in cropland and woodland; and (3) the improved NDVI was interpreted by expanding cropland and excessive groundwater irrigation, according to the positive effect of grain yield on NDVI all over the Horqin area. For persistent desertification reversion, a land use strategy should be more adaptive to the carrying capacity in this agro-pastoral transitional zone, particularly with respect to water capacity.
وصف الملف: application/pdf
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::83ce0028a896db29ef7031a1fc4f4d84Test
http://www.mdpi.com/2071-1050/9/2/211Test
النص الكامل