The Experts below are selected from a list of 38541 Experts worldwide ranked by ideXlab platform
Fuzhong Wu - One of the best experts on this subject based on the ideXlab platform.
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Carbon, nitrogen and phosphorus stocks in soil Organic Layer as affected by forest gaps in the alpine forest of the eastern Tibet Plateau
Russian Journal of Ecology, 2015Co-Authors: Qiqian Wu, Wanqin Yang, Fuzhong Wu, Xiangyin Ni, Yulian YangAbstract:Carbon (C) and nutrients storages in soil Organic Layer play an important role in forest productivity in the alpine-gorge area. However, forest gaps during forest regeneration could regulate carbon and nutrients stocks in soil Organic Layer by controlling hydro-thermal environment conditions, but little information has been available on it. Therefore, concentrations and stocks of carbon, nitrogen (N) and phosphorus (P) in fresh litter Layer (LL), fragmented litter Layer (FL) and humified litter Layer (HL) were investigated from gap center, canopy gap and expanded gap to closed canopy in an alpine forest of eastern Tibetan Plateau in later fall (October, 2013). The results showed that the forest gaps reduced the thicknesses of LL and FL, but increased the thickness of HL. Carbon concentrations in LL and FL decreased as affected by forest gaps, whereas both N and P concentrations increased regardless of soil Organic Layers. Moreover, forest gaps reduced C, N and P stocks in LL and FL, although which in HL increased. In addition, C, N and P stocks were significantly related to negative accumulated temperature regardless of soil Organic Layers. These results suggest that forest gap could promote carbon and nutrient releases from fresh litters, but limit carbon and nutrients output from humified litters in these alpine forests.
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effect of seasonal freeze thaw cycle on net nitrogen mineralization of soil Organic Layer in the subalpine alpine forests of western sichuan china
Acta Ecologica Sinica, 2013Co-Authors: Fuzhong Wu, Yulian Yang, Wanqin Yang, Ao Wang, Zhichao WuAbstract:Abstract Nitrogen mineralization, a main way that soil Organic nitrogen converts to mineral nitrogen, is one of the key processes in soil nitrogen cycle. The mineral nitrogen has an important role in plant growth in the growing season. It has been widely accepted that soil freezing in winter can kill a number of microorganisms, weakening soil nitrogen mineralization. However, more and more recent studies have documented that soil microorganisms still have high activity during the deep freezing period, and obvious nitrogen mineralization in winter. Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, which may have a strong effect on soil ecological processes. Furthermore, the changing pattern of seasonal freeze–thaw cycles might have a significant influence on soil nitrogen mineralization in this region in the scenarios of global warming. As yet, little attention has been given to nitrogen mineralization of soil Organic Layer as affected by changed seasonal freeze–thaw pattern, although the increasing studies have demonstrated that winter warming might give strong effects on the litter decomposition and microbial activity in the subalpine/alpine forest regions. Therefore, a method of intact soil core incubation in combination with natural environmental gradient was employed by transferring forest soils from 3582 m ( A 1 ) of altitude to 3298 m ( A 2 ) of altitude and 3023 m ( A 3 ) of altitude in the subalpine/alpine forests of western Sichuan, respectively. The amounts and rates of net nitrogen mineralization in soil Organic Layer were measured. The incubation period included the growing season and the freeze–thaw season from May 24, 2010 to April 19, 2011. The results suggested that significant net nitrogen mineralization was only observed in soil Organic Layer at low altitude ( A 3 ) during the whole incubation period. Forest soils at higher altitudes ( A 1 and A 2 ) showed obvious soil nitrogen immobilization. In comparison with the growing season which showed remarkable nitrogen immobilization characteristic, the freeze–thaw season showed obvious nitrogen mineralization at lower altitudes ( A 2 and A 3 ). In contrast, the nitrogen immobilization amounts at high altitude ( A 1 ) in freeze–thaw period were less than those in the growing season. Besides, the maximum of net nitrogen mineralization amounts and rates at high altitude ( A 1 ) in soil Organic Layer mainly occurred in the late stage of growing season and the onset of freezing, soil nitrogen mineralization at the middle altitude ( A 2 ) mainly occurred in the onset of freezing and the deep freezing period, while the highest amount and rate of net nitrogen mineralization at low altitude ( A 3 ) occurred in the early stage of thawing and the late stage of growing season. Furthermore, the amount and rate of soil net nitrogen mineralization during the freeze–thaw season were increasing with the decrease of altitude, which correlated with soil freeze–thaw cycle and freezing process at different altitudes. These results indicated that increasing soil temperature in the future could not only significantly enhance soil nitrogen mineralization in the freeze–thaw season, but also improve soil nitrogen mineralization by increasing freeze–thaw cycle times and shortening freeze–thaw period. However, the processes were significantly influenced by soil micro-environment of subalpine/alpine forest regions.
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characteristics of soil animal community in the subalpine alpine forests of western sichuan during onset of freezing
Acta Ecologica Sinica, 2010Co-Authors: Fuzhong Wu, Wanqin Yang, Sheng YuAbstract:Abstract Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil Layer, the soil Organic Layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil Organic Layer and mineral soil Layer, and this trend in soil Organic Layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil Organic Layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.
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Characteristics of soil animal community in the subalpine/alpine forests of western Sichuan during onset of freezing
Acta Ecologica Sinica, 2010Co-Authors: Fuzhong Wu, Wanqin Yang, Sheng YuAbstract:Abstract Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil Layer, the soil Organic Layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil Organic Layer and mineral soil Layer, and this trend in soil Organic Layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil Organic Layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.
Sheng Yu - One of the best experts on this subject based on the ideXlab platform.
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characteristics of soil animal community in the subalpine alpine forests of western sichuan during onset of freezing
Acta Ecologica Sinica, 2010Co-Authors: Fuzhong Wu, Wanqin Yang, Sheng YuAbstract:Abstract Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil Layer, the soil Organic Layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil Organic Layer and mineral soil Layer, and this trend in soil Organic Layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil Organic Layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.
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Characteristics of soil animal community in the subalpine/alpine forests of western Sichuan during onset of freezing
Acta Ecologica Sinica, 2010Co-Authors: Fuzhong Wu, Wanqin Yang, Sheng YuAbstract:Abstract Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil Layer, the soil Organic Layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil Organic Layer and mineral soil Layer, and this trend in soil Organic Layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil Organic Layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.
Jin-seong Park - One of the best experts on this subject based on the ideXlab platform.
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Effects of Repetitive Mechanical Stress on Flexible Oxide Thin-Film Transistors and Stress Reduction via Additional Organic Layer
IEEE Electron Device Letters, 2018Co-Authors: Hyun-jun Jeong, Kyung-sub Jeong, Saeroonter Oh, Jin-seong ParkAbstract:We investigated the effects of repetitive mechanical bending stress on top-gate amorphous InGaZnO thin-film transistors (TFTs). Electrical parameters were gradually degraded under repetitive tensile bending stress. After 50 000 bending cycles, some TFTs showed gate leakage current increase during positive gate bias thermal stress. After 60 000 bending cycles, conduction path was physically severed to an open state. However, when an additional Organic Layer was deposited on the TFTs as a stress-reduction Layer, device characteristics were unaffected by repetitive mechanical stress up to 100 000 cycles. Finite element structural simulations show the vulnerable stress-concentrated regions that cause leakage current, contact resistance increase, and interface traps. Electrical deterioration under repetitive bending is significantly mitigated by applying a stress-reduction Layer.
Wanqin Yang - One of the best experts on this subject based on the ideXlab platform.
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Carbon, nitrogen and phosphorus stocks in soil Organic Layer as affected by forest gaps in the alpine forest of the eastern Tibet Plateau
Russian Journal of Ecology, 2015Co-Authors: Qiqian Wu, Wanqin Yang, Fuzhong Wu, Xiangyin Ni, Yulian YangAbstract:Carbon (C) and nutrients storages in soil Organic Layer play an important role in forest productivity in the alpine-gorge area. However, forest gaps during forest regeneration could regulate carbon and nutrients stocks in soil Organic Layer by controlling hydro-thermal environment conditions, but little information has been available on it. Therefore, concentrations and stocks of carbon, nitrogen (N) and phosphorus (P) in fresh litter Layer (LL), fragmented litter Layer (FL) and humified litter Layer (HL) were investigated from gap center, canopy gap and expanded gap to closed canopy in an alpine forest of eastern Tibetan Plateau in later fall (October, 2013). The results showed that the forest gaps reduced the thicknesses of LL and FL, but increased the thickness of HL. Carbon concentrations in LL and FL decreased as affected by forest gaps, whereas both N and P concentrations increased regardless of soil Organic Layers. Moreover, forest gaps reduced C, N and P stocks in LL and FL, although which in HL increased. In addition, C, N and P stocks were significantly related to negative accumulated temperature regardless of soil Organic Layers. These results suggest that forest gap could promote carbon and nutrient releases from fresh litters, but limit carbon and nutrients output from humified litters in these alpine forests.
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effect of seasonal freeze thaw cycle on net nitrogen mineralization of soil Organic Layer in the subalpine alpine forests of western sichuan china
Acta Ecologica Sinica, 2013Co-Authors: Fuzhong Wu, Yulian Yang, Wanqin Yang, Ao Wang, Zhichao WuAbstract:Abstract Nitrogen mineralization, a main way that soil Organic nitrogen converts to mineral nitrogen, is one of the key processes in soil nitrogen cycle. The mineral nitrogen has an important role in plant growth in the growing season. It has been widely accepted that soil freezing in winter can kill a number of microorganisms, weakening soil nitrogen mineralization. However, more and more recent studies have documented that soil microorganisms still have high activity during the deep freezing period, and obvious nitrogen mineralization in winter. Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, which may have a strong effect on soil ecological processes. Furthermore, the changing pattern of seasonal freeze–thaw cycles might have a significant influence on soil nitrogen mineralization in this region in the scenarios of global warming. As yet, little attention has been given to nitrogen mineralization of soil Organic Layer as affected by changed seasonal freeze–thaw pattern, although the increasing studies have demonstrated that winter warming might give strong effects on the litter decomposition and microbial activity in the subalpine/alpine forest regions. Therefore, a method of intact soil core incubation in combination with natural environmental gradient was employed by transferring forest soils from 3582 m ( A 1 ) of altitude to 3298 m ( A 2 ) of altitude and 3023 m ( A 3 ) of altitude in the subalpine/alpine forests of western Sichuan, respectively. The amounts and rates of net nitrogen mineralization in soil Organic Layer were measured. The incubation period included the growing season and the freeze–thaw season from May 24, 2010 to April 19, 2011. The results suggested that significant net nitrogen mineralization was only observed in soil Organic Layer at low altitude ( A 3 ) during the whole incubation period. Forest soils at higher altitudes ( A 1 and A 2 ) showed obvious soil nitrogen immobilization. In comparison with the growing season which showed remarkable nitrogen immobilization characteristic, the freeze–thaw season showed obvious nitrogen mineralization at lower altitudes ( A 2 and A 3 ). In contrast, the nitrogen immobilization amounts at high altitude ( A 1 ) in freeze–thaw period were less than those in the growing season. Besides, the maximum of net nitrogen mineralization amounts and rates at high altitude ( A 1 ) in soil Organic Layer mainly occurred in the late stage of growing season and the onset of freezing, soil nitrogen mineralization at the middle altitude ( A 2 ) mainly occurred in the onset of freezing and the deep freezing period, while the highest amount and rate of net nitrogen mineralization at low altitude ( A 3 ) occurred in the early stage of thawing and the late stage of growing season. Furthermore, the amount and rate of soil net nitrogen mineralization during the freeze–thaw season were increasing with the decrease of altitude, which correlated with soil freeze–thaw cycle and freezing process at different altitudes. These results indicated that increasing soil temperature in the future could not only significantly enhance soil nitrogen mineralization in the freeze–thaw season, but also improve soil nitrogen mineralization by increasing freeze–thaw cycle times and shortening freeze–thaw period. However, the processes were significantly influenced by soil micro-environment of subalpine/alpine forest regions.
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characteristics of soil animal community in the subalpine alpine forests of western sichuan during onset of freezing
Acta Ecologica Sinica, 2010Co-Authors: Fuzhong Wu, Wanqin Yang, Sheng YuAbstract:Abstract Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil Layer, the soil Organic Layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil Organic Layer and mineral soil Layer, and this trend in soil Organic Layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil Organic Layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.
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Characteristics of soil animal community in the subalpine/alpine forests of western Sichuan during onset of freezing
Acta Ecologica Sinica, 2010Co-Authors: Fuzhong Wu, Wanqin Yang, Sheng YuAbstract:Abstract Seasonal freeze–thaw cycle is a common phenomenon in the subalpine/alpine forest region, and may have a significant influence on the structure and function of soil animal community. To understand the characteristics and dynamics of soil animal community as well as its response to repeated freeze–thaw events in this region during onset of freezing, a field experiment was conducted to investigate the composition, abundance, and diversity of soil fauna in primary fir (Abies faxoniana) forest, fir and birch (Betula albosinensis) mixed forest and secondary fir (A. faxoniana) forest, which were three representative forests in the subalpine and alpine forest region in western Sichuan. Soil samples were collected from November 3 to November 27, 2008, which was defined as onset of freezing based on the simultaneous monitoring of soil temperature. Soil macrofauna were picked up by hand in the fields. Mesofauna were separated and collected from the soil samples by Baermann and Tullgren methods, respectively. By preliminary identification, 40,942 individuals were collected, which belonged to 7 phyla, 15 classes and 25 orders in the three sampling forests. 16,557, 14,669 and 9716 individuals were found in primary forest, mixed forest and secondary forest, respectively. In comparison with the mineral soil Layer, the soil Organic Layer had higher density and groups of soil fauna. Furthermore, following the repeated freeze–thaw events, density and groups of soil fauna experienced a distinct decrease in both soil Organic Layer and mineral soil Layer, and this trend in soil Organic Layer was more significant in the primary forest, owing to higher intense and more frequent freeze–thaw cycles in soil Organic Layer of the primary forest. The results revealed that soil animals were sensitive bio-indicators to environmental changes, such as repeated freeze–thaw events and dry–wet cycle. Meanwhile, the results also implied that the dynamics of the structure and function of soil animal community during the onset of freezing was of ecological significance to understand the wintertime ecological process in soils.
E A Schiff - One of the best experts on this subject based on the ideXlab platform.
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conducting polymer and hydrogenated amorphous silicon hybrid solar cells
Applied Physics Letters, 2005Co-Authors: Evan L Williams, Ghassan E Jabbour, Qi Wang, Sean E Shaheen, David S Ginley, E A SchiffAbstract:An Organic-inOrganic hybrid solar cell with a p-i-n stack structure has been investigated. The p-Layer was a spin coated film of PEDOT:PSS [poly(3,4-ethylenedioxythiophene) poly (styrenesulfonate)]. The i-Layer was hydrogenated amorphous silicon (a-Si:H), and the n-Layer was microcrystalline silicon (μc-Si). The inOrganic Layers were deposited on top of the Organic Layer by the hot-wire chemical vapor deposition technique at 200°C. These hybrid devices exhibited open circuit voltages (VOC) as large as 0.88V and solar conversion efficiencies as large as 2.1%. Comparison of these devices with those incorporating a-SiC:H:B p-Layers indicates that the Organic Layer is acting as an electrically ideal p-Layer.