According to the connotation and structure of science and technology resources and some relevant data of more than 286 cities at prefecture level and above during 2001-2010, using modified method--Data Envelopment Ana...According to the connotation and structure of science and technology resources and some relevant data of more than 286 cities at prefecture level and above during 2001-2010, using modified method--Data Envelopment Analysis （DEA）, science and tech- nology （S＆T） resource allocation efficiency of different cities in different periods has been figured out, which, uncovers the distributional difference and change law of S＆T resource allocation efficiency from the time-space dimension. Based on that, this paper has analyzed and discussed the spatial distribution pattern and evolution trend of S＆T resource allocation efficiency in different cities by virtue of the Exploratory Spatial Data Analysis （ESDA）. It turned out that： （1） the average of S＆T resource allocation efficiency in cities at prefecture level and above has always stayed at low levels, moreover, with repeated fluctuations between high and low, which shows a decreasing trend year by year. Besides, the gap between the East and the West is widening. （2） The asymmetrical distribution of S＆T resource allocation effi- ciency presents a spatial pattern of successively decreasing from Eastern China, Central China to Western China. The cities whose S＆T resource allocation efficiency are at higher level and high level take on a cluster distribution, which fits well with the 23 forming urban agglomerations in China. （3） The coupling degree between S＆T resource allocation efficiency and economic environment assumes a certain positive correlation, but not completely the same. The differentiation of S＆T resource allocation efficiency is common in regional devel- opment, whose existence and evolution are directly or indirectly influenced by and regarded as the reflection of many elements, such as geographical location, the natural endowment and environment of S＆T resources and so on. （4） In the perspective of the evolution of spatial structure, S＆T resource allocation efficiency of the cities at prefecture level and above展开更多
This study presents the utility of remote sensing （RS）, GIS and field observation data to estimate above ground biomass （AGB） and stem volume over tropical forest environment. Application of those data for the mod...This study presents the utility of remote sensing （RS）, GIS and field observation data to estimate above ground biomass （AGB） and stem volume over tropical forest environment. Application of those data for the modeling of forest properties is site specific and highly uncertain, thus further study is encouraged. In this study we used 1460 sampling plots collected in 16 transects measuring tree diameter （DBH） and other forest properties which were useful for the biomass assessment. The study was carded out in tropical forest region in East Kalimantan, Indo- nesia. The AGB density was estimated applying an existing DBH - biomass equation. The estimate was superimposed over the modified GIS map of the study area, and the biomass density of each land cover was calculated. The RS approach was performed using a subset of sample data to develop the AGB and stem volume linear equation models. Pearson correlation statistics test was conducted using ETM bands reflectance, vegetation indices, image transform layers, Principal Component Analysis （PCA） bands, Tasseled Cap （TC）, Grey Level Co-Occurrence Matrix （GLCM） texture features and DEM data as the predictors. Two linear models were generated from the significant RS data. To analyze total biomass and stem volume of each land cover, Landsat ETM images from 2000 and 2003 were preprocessed, classified using maximum likelihood method, and filtered with the majority analysis. We found 158±16 m^3.ha^-1 of stem volume and 168±15 t.ha^-1 of AGB estimated from RS approach, whereas the field measurement and GIS estimated 157±92 m^3.ha^-1 and 167±94 t.ha^-1 of stem volume and AGB, respectively. The dynamics of biomass abundance from 2000 to 2003 were assessed from multi temporal ETM data and we found a slightly declining trend of total biomass over these periods. Remote sensing approach estimated lower biomass abundance than did the GIS and field measurement data. The earlier approach predicted 10.5 Gt and 10.3 Gt of total biomasses in 2000 and 2003, while展开更多
This study describes the different parameters used to derive the allometric equation for calculating the biomass of an invasive woody shrub Lantana camara L.from the subtropical conditions of western Himalaya.It ident...This study describes the different parameters used to derive the allometric equation for calculating the biomass of an invasive woody shrub Lantana camara L.from the subtropical conditions of western Himalaya.It identifies the most accurate and convenient method for biomass calculation by comparing destructive with nondestructive methodology.Different parameters were measured on a wide range of Lantana from different community levels for the non-destructive calculation of total aboveground biomass.Different explanatory variables were identified and measured such as basal diameter either as a single independent variable or in combination with plant height.The other suitable combinations of available independent variables include crown length,crown width,crown area,crown volume and coverage of the plant.Amongst the wide range of allometric equations used with different variables,the equation with D2 H as a variable was found to be the most suitable estimator of biomass calculation for Lantana.Sahastradhara,being the most disturbed area due to its high tourist activity round the year,showed maximum coverage（58.57 % ha-1）,highest biomass（13,559.60 kg ha-1） and carbon density（6,373.01 kg ha-1）of Lantana.The degree of Lantana’s invasiveness in subtropical conditions was also calculated on the basis of importance value index（IVI）.The maximum IVI（22.77）and mean coverage（26.8 % ha-1） was obtained from the areas near Jolly Grant airport,indicating that physically disturbed areas are more suitable for the growth of Lantana,which may significantly increase shrub biomass.The importance of incorporating allometric equations in calculation of shrub biomass,and its role in atmospheric carbon assimilation has thus been highlighted through the findings of this study.展开更多
This paper presents an application of gain-scheduling(GS) control techniques to a floating offshore wind turbine on a barge platform for above rated wind speed cases. Special emphasis is placed on the dynamics variati...This paper presents an application of gain-scheduling(GS) control techniques to a floating offshore wind turbine on a barge platform for above rated wind speed cases. Special emphasis is placed on the dynamics variation of the wind turbine system caused by plant nonlinearity with respect to wind speed. The turbine system with the dynamics variation is represented by a linear parameter-varying(LPV) model, which is derived by interpolating linearized models at various operating wind speeds. To achieve control objectives of regulating power capture and minimizing platform motions, both linear quadratic regulator(LQR) GS and LPV GS controller design techniques are explored. The designed controllers are evaluated in simulations with the NREL 5 MW wind turbine model, and compared with the baseline proportional-integral(PI) GS controller and non-GS controllers. The simulation results demonstrate the performance superiority of LQR GS and LPV GS controllers, as well as the performance trade-off between power regulation and platform movement reduction.展开更多
The United Nations Framework Convention on Climate Change （UNFCCC） requires reporting net carbon stock changes and anthropogenic greenhouse gas emissions, including those related to forests. This paper describes the...The United Nations Framework Convention on Climate Change （UNFCCC） requires reporting net carbon stock changes and anthropogenic greenhouse gas emissions, including those related to forests. This paper describes the status of carbon stocks in sub tropical forests of Pakistan. There are two major sub types in subtropical forests of Pakistan viz a viz Subtropical Chir Pine and Subtropical broadleaved forests. A network of sample plots was laid out in four selected site. Two sites were selected from sub tropical Chir Pine （Pinus roxburghii） forests and two from Subtropical broadleaved forests. Measurement and data acquisition protocols were developed specifically for the inventory car- ried out from 2005 to 2010. In total 261 plots （each of lha.） were established. Estimation of diameter, basal area, height, volume and biomass was carried out to estimate carbon stocks in each of the four carbon pools of above- and below-ground live biomass. Soil carbon stocks were also determined by doing soil sampling. In mature （-100 years old） pine forest stand at Ghoragali and Lehterar sites, a mean basal area of 30.38 and 26.11 m2.ha-1 represented mean volume of 243 and 197 m3·ha-1, respectively. The average biomass （t.ha-1） was 237 in Ghoragali site and 186 tha-1 in Lehterar site, which is equal to 128 and 100 t·ha-1 including soil C. However, on average basis both the forests have 114.5± 2.26 t.ha-1 of carbon stock which comprises of 92% in tree biomass and only 8% in the top soils. In mixed broadleaved evergreen forests a mean basal area （m2.ha-1）was 3.06 at Kherimurat with stem volume of 12.86 and 2.65 at Sohawa with stem volume of 11.40 m3.ha-1. The average upper and under storey biomass （t·ha-1） was 50.93 in Kherimurat site and 40.43 t.ha-1 in Sohawa site, which is equal to 31.18 and 24.36 t ·ha-1 including soil C stocks. This study provides a protocol monitoring biomass and carbon stocks and valuable baseline data for in Pakistan＇s managed and unmanaged sub-tropical forests.展开更多
Objective:To explore the diagnostic value of ultrasound imaging for breast nodules of breast imaging-reporting and data system(BI-RADS)category 3 and above.Methods:From June 2021 to July 2022,163 patients with breast ...Objective:To explore the diagnostic value of ultrasound imaging for breast nodules of breast imaging-reporting and data system(BI-RADS)category 3 and above.Methods:From June 2021 to July 2022,163 patients with breast nodules of BI-RADS 3 or above were selected as the research subjects.After pathological diagnosis,24 cases were malignant breast nodules of BI-RADS 3 or above,while 139 cases were benign breast nodules of BI-RADS 3 or above.The diagnosis rate of malignant and benign breast nodules of BI-RADS 3 or above,including 95%CI,was observed and analyzed.Results:The malignant and benign detection rates of conventional ultrasound were 88.63%and 75.00%,respectively,and the malignant and benign detection rates of ultrasound imaging were 93.18%and 87.50%,respectively,with 95%CIs greater than 0.7.Conclusion:Ultrasound imaging can help improve the diagnostic accuracy of benign and malignant breast nodules of BI-RADS 3 and above and reduce the misdiagnosis rate.展开更多
The temperature and moisture of the pavement structure can be greatly influenced by the wind speed above pavement surface.The wind speed above pavement surface not only is dominated by the wind speed of atmosphere,but...The temperature and moisture of the pavement structure can be greatly influenced by the wind speed above pavement surface.The wind speed above pavement surface not only is dominated by the wind speed of atmosphere,but also it is highly related to the landform and buildings around road.However,currently there are no studies about the wind field above pavement surface in consideration of the effect of the landform and buildings.A simulation method,which is combined with geographic information system(GIS),wind data from meteorological observatory and computational fluid dynamics(CFD)software,is employed to study the effect of the landform and the wind speed of atmosphere on the wind field above pavement surface.Three cases are studied,including an urban road,a coastal road and a mountainous road.Furthermore,the wind field distribution above road surface in different wind directions was studied in our work.Results indicate that the wind field above pavement surface can be greatly affected by the landforms,buildings and wind direction.This simulation method can provide reliable results for the wind field above pavement surface.The maximum relative errors between simulated and measured wind speed can be less than 20%in the analysis of the three cases.It is recommended that the CFD simulation method is a good tool to accurately know the wind field above pavement surface.展开更多
The mountainous and hilly region plays an important role in ecological safety and production in China. However, recent studies have poorly characterized the parallel structure of land use in the valleys of the mountai...The mountainous and hilly region plays an important role in ecological safety and production in China. However, recent studies have poorly characterized the parallel structure of land use in the valleys of the mountainous and hilly region using topographic factors(e.g.elevation, slope, aspect). Here, the loess hilly region of northern Shaanxi Province is used as a representative case area to analyze the vertical distribution pattern of land-use conversion using the relative elevation concept and the HAND index. The differences in the vertical structure of land-use conversion between absolute elevation and relative elevation were compared. We found that the classifications of absolute and relative elevation had similar proportions of each relative elevation grade in each absolute elevation grade. Cropland,woodland, and grassland were distributed evenly in each grade of absolute/relative elevation,while water body, built-up land and unused land were more likely to spread in low grades of relative elevation than those of absolute elevation. The land-use conversion(i.e. loss of cropland and gain in woodland and built-up land) showed an apparently stepped distribution with relative elevation classification, suitable for revealing vertical distributions of land-use conversion in the loess hilly region. Cropland transformed to woodland was mainly distributed in high grade of relative elevation, decreasing with a decrease in grades, while built-up land transformed from cropland and grassland was mainly distributed in low grade of relative elevation, decreasing with increases in grades. The grade of relative elevation where cropland transformed to woodland descended with the implementation of the Grain for Green Project. Our results suggest that it is better to analyze the vertical distribution of land-use conversion with relative elevation classification in hilly regions.展开更多
Tropical rainforests are crucial in maintaining about 70% of the world’s plant and animal biodiversity and are also the highest terrestrial carbon reservoir. This study aimed to determine the tree species composition...Tropical rainforests are crucial in maintaining about 70% of the world’s plant and animal biodiversity and are also the highest terrestrial carbon reservoir. This study aimed to determine the tree species composition, structure and carbon stocks of the Deng Deng National Park which is a semi-deciduous tropical forest (plots 1 and 2 and the transition zone to the savannah (plot 3). Plots demarcation and enumeration followed standard protocols for permanent monitoring plots. The inventory of tree species ≥ 2 cm revealed a total of 5523 individuals of 64 species in 53 genera belonging to 26 families with plot 2 having the highest (2135 individuals/ha) and plot 3 the least (1291 individuals/ha). Tabernaemontana crassa was the most important tree species in the tropical forest and Lecythis idatimon in the savannah. Basal area was highest in the tropical forest and least in the savannah. The diameter distribution of trees in all forest types displayed a reverse J-pattern. Aboveground biomass was highest in the tropical forest (530.2 ± 66.4 t·C/ha) and least in the savannah (184.3 ± 20.1 t·C/ha). The carbon stock of the above ground biomass was twice as much as that of the below ground biomass, soil organic matter and litter. The total carbon stock estimated in all pools was 278.75 t·C/ha. The study site was poor in plant diversity, biomass and carbon stock, indicating a disturbed site with the absence of large trees and undergoing natural regeneration. This underlines an urgent need for efficient restoration management practices.展开更多
We investigate the effect of dopant random fluctuation on threshold voltage and drain current variation in a two-gate nanoscale transistor. We used a quantum-corrected technology computer aided design simulation to ru...We investigate the effect of dopant random fluctuation on threshold voltage and drain current variation in a two-gate nanoscale transistor. We used a quantum-corrected technology computer aided design simulation to run the simulation （10000 randomizations）. With this simulation, we could study the effects of varying the dimensions （length and width）, and thicknesses of oxide and dopant factors of a transistor on the threshold voltage and drain current in subthreshold region （off） and overthreshold （on）. It was found that in the subthreshold region the variability of the drain current and threshold voltage is relatively fixed while in the overthreshold region the variability of the threshold voltage and drain current decreases remarkably, despite the slight reduction of gate voltage diffusion （compared with that of the subthreshold）. These results have been interpreted by using previously reported models for threshold current variability, load displacement, and simple analytical calculations. Scaling analysis shows that the variability of the characteristics of this semiconductor increases as the effects of the short channel increases. Therefore, with a slight increase of length and a reduction of width, oxide thickness, and dopant factor, we could correct the effect of the short channel.展开更多
The above-threshold ionization of argon in an intense 70-fs,400-nm linearly polarized laser pulse has been investigated by the velocity map imaging techniques,combined with an attosecond-resolution quantum wave packet...The above-threshold ionization of argon in an intense 70-fs,400-nm linearly polarized laser pulse has been investigated by the velocity map imaging techniques,combined with an attosecond-resolution quantum wave packet dynamics method.There is a quantitative agreement in all dominant features between the experiment and the theory.Moreover,a peak-splitting phenomenon in the first energy peak has been observed at high pulse intensity.Further,through the theoretical analysis,an ac Stark splitting with evident resonant and nonresonant ionization pathways has been found to be the physical reason for the experimental observations.展开更多
A novel high voltage switching circuit with parallel resonant topology is analyzed.Without adding other resonant components,this circuit makes full use of the transformer leakage inductance and winding capacitance so ...A novel high voltage switching circuit with parallel resonant topology is analyzed.Without adding other resonant components,this circuit makes full use of the transformer leakage inductance and winding capacitance so as to reduce the influence of the transformer parasitic parameter.Using device CD4046 to realize the switching control of MOS,this circuit can realize the constant-current charging to capacitor by operating the above resonance.The operating process of the circuit is analyzed,and the power calculation and some practical waveforms are given.展开更多
Twenty-six sequences of grades of dryness/wetness and a combined sequence of indexes of winter temperature since A.D. 1471 in China were adopted as our data. The fluctuations of variability of precipitation and mean t...Twenty-six sequences of grades of dryness/wetness and a combined sequence of indexes of winter temperature since A.D. 1471 in China were adopted as our data. The fluctuations of variability of precipitation and mean temperature are statistically significant from analyses. It has been found that in middle latitudes of eastern China the distribution of the relation between mean temperature and interannual variability of precipitation in historical time forms a rather complex regional pattern, and the correlation coefficients are not unique in signs. But the negative correlations are dominant either in extent or in magnitude. The authors provide evidence that Little Ice Age was a time of more frequent extremes and support the idea that the climatic instability is above normal in cool periods.展开更多
Above ground gas storage devices for compressed air energy storage(CAES) have three types:air storage tanks,gas cylinders,and gas storage pipelines.A cost model of these gas storage devices is established on the basis...Above ground gas storage devices for compressed air energy storage(CAES) have three types:air storage tanks,gas cylinders,and gas storage pipelines.A cost model of these gas storage devices is established on the basis of whole life cycle cost(LCC) analysis.The optimum parameters of the three types are determined by calculating the theoretical metallic raw material consumption of these three devices and considering the difficulties in manufacture and the influence of gas storage device number.The LCCs of the three types are comprehensively analyzed and compared.The result reveal that the cost of the gas storage pipeline type is lower than that of the other two types.This study may serve as a reference for designing large-scale CAES systems.展开更多
Telling Chinese stories and Chinese experience is an important theme of realist literature in the new era.Chinese writers in the new era face the significant challenge of how to understand the"totality of China&q...Telling Chinese stories and Chinese experience is an important theme of realist literature in the new era.Chinese writers in the new era face the significant challenge of how to understand the"totality of China"and how to construct the totality spirit and aesthetic character of the"Chinese"narrative.Above Baiyangdian Lake by Guan Renshan takes the historical changes that occurred in the typical environment of Baiyangdian New Area as the content of narration,revealing the growth of people and history and its"Chinese"connotation through the story of the growth of"new character"in the new era.The novel depicts the"rediscovery"and rebirth of history and traditions of China in the new era by"telling stories,"and puts them under a profound context of the past and present and in a broad vision of China and foreign countries,thus constructing the overall aesthetics of realism in contemporary China with an epic grand narrative.The novel artistically shows the building and growth process of China in the new era,and demonstrates its leveraging of resourcesand unique connotation.It is a typical text for understanding the relationshipbetween theimage shaping of China in the new era and Chinese realism literature,as well as the connotation,function and form of Chinese realism.展开更多
Above Baiyangdian Lake is a novel set against the backdrop of the great changes in rural China in the new era,revolving around the grand theme of China's contribution to the harmonious development of the world wit...Above Baiyangdian Lake is a novel set against the backdrop of the great changes in rural China in the new era,revolving around the grand theme of China's contribution to the harmonious development of the world with Chinese wisdom and its solutions.The subject of Above Baiyangdian Lake is grand as it involves politics,culture,economy,and many other aspects.Its publication has reversed the narrowing tendency of Chinese novels in terms of themes and subjects.Above Baiyangdian Lake reconstructs historical time for Chinese modernization with its time consciousness based on a historical perspective.Wang Juexin and Qiao Mai shaped by the writer have contributed to the range of Chinese contemporary literary characters as typical images of the new characters of the era.The value of epic masterpieces like Above Baiyangdian Lake should be fully explored and advocated to provide a useful reference for the development of literature in the newera.展开更多
Above Baiyangdian Lake is a meticulously crafted novel by Guan Renshan nearing a million words in length.The novel offers a panoramic view of everyday life in Baiyangdian Lake and the development of the Xiong'an N...Above Baiyangdian Lake is a meticulously crafted novel by Guan Renshan nearing a million words in length.The novel offers a panoramic view of everyday life in Baiyangdian Lake and the development of the Xiong'an New Area.The novel exemplifies a genuine sense of the scene by presenting readers with a vivid,authentic depiction of our contemporary life.He employs a narrative structure that overlaps the present with the past,blending tradition and modernity to create a truly magnificent epic.Rather than avoiding the contradictions and darkness inherent to humanity,the novel embraces them and strives to accurately depict their complexity,resulting in a more profound reflection on society.Above Baiyangdian Lake expands and innovates the path of local literature by applying a genuinely realistic approach.It not only surpasses Guan's writing style,but also represents a transcendence of local writing conventions in contemporary literature.It draws upon and elevates the literary tradition of the Hehuadian School,emerging as a notable example of new local writing with distinct regional traits.展开更多
Above Baiyangdian Lake is another full-length realistic novel written by Guan Renshan after The Maihe River.In this work,Guan Renshan goes beyond traditional rural writing and artistically narrates the grand landscape...Above Baiyangdian Lake is another full-length realistic novel written by Guan Renshan after The Maihe River.In this work,Guan Renshan goes beyond traditional rural writing and artistically narrates the grand landscape of Baiyangdian New Area and the changes of people's fate during its construction.With Guan's refined and mature narrative techniques,the novel clearly shows his ambition to present a“regional epic.”This paper delves into the fictional text and analyzes the structuring method of Above Baiyangdian Lake from multiple perspectives such as its character shaping with historical correspondence,and narrative structure,skills,and style,aiming to provide an approach to interpret the ideological schema of Above Baiyangdian Lake.展开更多
The degradation of phenol by pulsed discharge plasma above a liquid surface(APDP) and under a liquid surface(UPDP) was compared.The effects of discharge voltage,discharge distance,initial solution conductivity and ini...The degradation of phenol by pulsed discharge plasma above a liquid surface(APDP) and under a liquid surface(UPDP) was compared.The effects of discharge voltage,discharge distance,initial solution conductivity and initial p H on the removal of phenol were studied.It was concluded that the removal of phenol increases with increasing discharge voltage and with decreasing discharge distance in both APDP and UPDP systems.An increase in the initial solution’s conductivity has a positive effect in the APDP system but a negative effect in the UPDP system.In addition,alkaline conditions are conducive to the degradation of phenol in the APDP system,while acidic conditions are conducive in the UPDP system.Free radical quenching experiments revealed that ·O-2has an important influence on the degradation of phenol in the APDP system,while ·OH plays a key role in the UPDP system.This paper verifies the differences in the two discharge methods in terms of phenol removal.展开更多
基金Key Projects of Philosophy of the Social Science funded by the Ministry of Education,No.11JD039National Key Public Bidding Project for Soft Science Research Plan,No.2012GXS1D002National Natural Science Foundation of China,No.41001083
文摘According to the connotation and structure of science and technology resources and some relevant data of more than 286 cities at prefecture level and above during 2001-2010, using modified method--Data Envelopment Analysis （DEA）, science and tech- nology （S＆T） resource allocation efficiency of different cities in different periods has been figured out, which, uncovers the distributional difference and change law of S＆T resource allocation efficiency from the time-space dimension. Based on that, this paper has analyzed and discussed the spatial distribution pattern and evolution trend of S＆T resource allocation efficiency in different cities by virtue of the Exploratory Spatial Data Analysis （ESDA）. It turned out that： （1） the average of S＆T resource allocation efficiency in cities at prefecture level and above has always stayed at low levels, moreover, with repeated fluctuations between high and low, which shows a decreasing trend year by year. Besides, the gap between the East and the West is widening. （2） The asymmetrical distribution of S＆T resource allocation effi- ciency presents a spatial pattern of successively decreasing from Eastern China, Central China to Western China. The cities whose S＆T resource allocation efficiency are at higher level and high level take on a cluster distribution, which fits well with the 23 forming urban agglomerations in China. （3） The coupling degree between S＆T resource allocation efficiency and economic environment assumes a certain positive correlation, but not completely the same. The differentiation of S＆T resource allocation efficiency is common in regional devel- opment, whose existence and evolution are directly or indirectly influenced by and regarded as the reflection of many elements, such as geographical location, the natural endowment and environment of S＆T resources and so on. （4） In the perspective of the evolution of spatial structure, S＆T resource allocation efficiency of the cities at prefecture level and above
文摘This study presents the utility of remote sensing （RS）, GIS and field observation data to estimate above ground biomass （AGB） and stem volume over tropical forest environment. Application of those data for the modeling of forest properties is site specific and highly uncertain, thus further study is encouraged. In this study we used 1460 sampling plots collected in 16 transects measuring tree diameter （DBH） and other forest properties which were useful for the biomass assessment. The study was carded out in tropical forest region in East Kalimantan, Indo- nesia. The AGB density was estimated applying an existing DBH - biomass equation. The estimate was superimposed over the modified GIS map of the study area, and the biomass density of each land cover was calculated. The RS approach was performed using a subset of sample data to develop the AGB and stem volume linear equation models. Pearson correlation statistics test was conducted using ETM bands reflectance, vegetation indices, image transform layers, Principal Component Analysis （PCA） bands, Tasseled Cap （TC）, Grey Level Co-Occurrence Matrix （GLCM） texture features and DEM data as the predictors. Two linear models were generated from the significant RS data. To analyze total biomass and stem volume of each land cover, Landsat ETM images from 2000 and 2003 were preprocessed, classified using maximum likelihood method, and filtered with the majority analysis. We found 158±16 m^3.ha^-1 of stem volume and 168±15 t.ha^-1 of AGB estimated from RS approach, whereas the field measurement and GIS estimated 157±92 m^3.ha^-1 and 167±94 t.ha^-1 of stem volume and AGB, respectively. The dynamics of biomass abundance from 2000 to 2003 were assessed from multi temporal ETM data and we found a slightly declining trend of total biomass over these periods. Remote sensing approach estimated lower biomass abundance than did the GIS and field measurement data. The earlier approach predicted 10.5 Gt and 10.3 Gt of total biomasses in 2000 and 2003, while
文摘This study describes the different parameters used to derive the allometric equation for calculating the biomass of an invasive woody shrub Lantana camara L.from the subtropical conditions of western Himalaya.It identifies the most accurate and convenient method for biomass calculation by comparing destructive with nondestructive methodology.Different parameters were measured on a wide range of Lantana from different community levels for the non-destructive calculation of total aboveground biomass.Different explanatory variables were identified and measured such as basal diameter either as a single independent variable or in combination with plant height.The other suitable combinations of available independent variables include crown length,crown width,crown area,crown volume and coverage of the plant.Amongst the wide range of allometric equations used with different variables,the equation with D2 H as a variable was found to be the most suitable estimator of biomass calculation for Lantana.Sahastradhara,being the most disturbed area due to its high tourist activity round the year,showed maximum coverage（58.57 % ha-1）,highest biomass（13,559.60 kg ha-1） and carbon density（6,373.01 kg ha-1）of Lantana.The degree of Lantana’s invasiveness in subtropical conditions was also calculated on the basis of importance value index（IVI）.The maximum IVI（22.77）and mean coverage（26.8 % ha-1） was obtained from the areas near Jolly Grant airport,indicating that physically disturbed areas are more suitable for the growth of Lantana,which may significantly increase shrub biomass.The importance of incorporating allometric equations in calculation of shrub biomass,and its role in atmospheric carbon assimilation has thus been highlighted through the findings of this study.
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)(No.11R82911)the Institute of Computing,Information and Cognitive Systems(ICICS)at the University of British Columbia
文摘This paper presents an application of gain-scheduling(GS) control techniques to a floating offshore wind turbine on a barge platform for above rated wind speed cases. Special emphasis is placed on the dynamics variation of the wind turbine system caused by plant nonlinearity with respect to wind speed. The turbine system with the dynamics variation is represented by a linear parameter-varying(LPV) model, which is derived by interpolating linearized models at various operating wind speeds. To achieve control objectives of regulating power capture and minimizing platform motions, both linear quadratic regulator(LQR) GS and LPV GS controller design techniques are explored. The designed controllers are evaluated in simulations with the NREL 5 MW wind turbine model, and compared with the baseline proportional-integral(PI) GS controller and non-GS controllers. The simulation results demonstrate the performance superiority of LQR GS and LPV GS controllers, as well as the performance trade-off between power regulation and platform movement reduction.
文摘The United Nations Framework Convention on Climate Change （UNFCCC） requires reporting net carbon stock changes and anthropogenic greenhouse gas emissions, including those related to forests. This paper describes the status of carbon stocks in sub tropical forests of Pakistan. There are two major sub types in subtropical forests of Pakistan viz a viz Subtropical Chir Pine and Subtropical broadleaved forests. A network of sample plots was laid out in four selected site. Two sites were selected from sub tropical Chir Pine （Pinus roxburghii） forests and two from Subtropical broadleaved forests. Measurement and data acquisition protocols were developed specifically for the inventory car- ried out from 2005 to 2010. In total 261 plots （each of lha.） were established. Estimation of diameter, basal area, height, volume and biomass was carried out to estimate carbon stocks in each of the four carbon pools of above- and below-ground live biomass. Soil carbon stocks were also determined by doing soil sampling. In mature （-100 years old） pine forest stand at Ghoragali and Lehterar sites, a mean basal area of 30.38 and 26.11 m2.ha-1 represented mean volume of 243 and 197 m3·ha-1, respectively. The average biomass （t.ha-1） was 237 in Ghoragali site and 186 tha-1 in Lehterar site, which is equal to 128 and 100 t·ha-1 including soil C. However, on average basis both the forests have 114.5± 2.26 t.ha-1 of carbon stock which comprises of 92% in tree biomass and only 8% in the top soils. In mixed broadleaved evergreen forests a mean basal area （m2.ha-1）was 3.06 at Kherimurat with stem volume of 12.86 and 2.65 at Sohawa with stem volume of 11.40 m3.ha-1. The average upper and under storey biomass （t·ha-1） was 50.93 in Kherimurat site and 40.43 t.ha-1 in Sohawa site, which is equal to 31.18 and 24.36 t ·ha-1 including soil C stocks. This study provides a protocol monitoring biomass and carbon stocks and valuable baseline data for in Pakistan＇s managed and unmanaged sub-tropical forests.
文摘Objective:To explore the diagnostic value of ultrasound imaging for breast nodules of breast imaging-reporting and data system(BI-RADS)category 3 and above.Methods:From June 2021 to July 2022,163 patients with breast nodules of BI-RADS 3 or above were selected as the research subjects.After pathological diagnosis,24 cases were malignant breast nodules of BI-RADS 3 or above,while 139 cases were benign breast nodules of BI-RADS 3 or above.The diagnosis rate of malignant and benign breast nodules of BI-RADS 3 or above,including 95%CI,was observed and analyzed.Results:The malignant and benign detection rates of conventional ultrasound were 88.63%and 75.00%,respectively,and the malignant and benign detection rates of ultrasound imaging were 93.18%and 87.50%,respectively,with 95%CIs greater than 0.7.Conclusion:Ultrasound imaging can help improve the diagnostic accuracy of benign and malignant breast nodules of BI-RADS 3 and above and reduce the misdiagnosis rate.
基金funds from the National Key R&D Program of China(2018YFB1600100)the National Natural Science Foundation of China(52178417)。
文摘The temperature and moisture of the pavement structure can be greatly influenced by the wind speed above pavement surface.The wind speed above pavement surface not only is dominated by the wind speed of atmosphere,but also it is highly related to the landform and buildings around road.However,currently there are no studies about the wind field above pavement surface in consideration of the effect of the landform and buildings.A simulation method,which is combined with geographic information system(GIS),wind data from meteorological observatory and computational fluid dynamics(CFD)software,is employed to study the effect of the landform and the wind speed of atmosphere on the wind field above pavement surface.Three cases are studied,including an urban road,a coastal road and a mountainous road.Furthermore,the wind field distribution above road surface in different wind directions was studied in our work.Results indicate that the wind field above pavement surface can be greatly affected by the landforms,buildings and wind direction.This simulation method can provide reliable results for the wind field above pavement surface.The maximum relative errors between simulated and measured wind speed can be less than 20%in the analysis of the three cases.It is recommended that the CFD simulation method is a good tool to accurately know the wind field above pavement surface.
基金National Key Research and Development Program of China,No.2017YFC0504701National Natural Science Foundation of China,No.41801175Postdoctoral Science Foundation of China,No.2018M631558
文摘The mountainous and hilly region plays an important role in ecological safety and production in China. However, recent studies have poorly characterized the parallel structure of land use in the valleys of the mountainous and hilly region using topographic factors(e.g.elevation, slope, aspect). Here, the loess hilly region of northern Shaanxi Province is used as a representative case area to analyze the vertical distribution pattern of land-use conversion using the relative elevation concept and the HAND index. The differences in the vertical structure of land-use conversion between absolute elevation and relative elevation were compared. We found that the classifications of absolute and relative elevation had similar proportions of each relative elevation grade in each absolute elevation grade. Cropland,woodland, and grassland were distributed evenly in each grade of absolute/relative elevation,while water body, built-up land and unused land were more likely to spread in low grades of relative elevation than those of absolute elevation. The land-use conversion(i.e. loss of cropland and gain in woodland and built-up land) showed an apparently stepped distribution with relative elevation classification, suitable for revealing vertical distributions of land-use conversion in the loess hilly region. Cropland transformed to woodland was mainly distributed in high grade of relative elevation, decreasing with a decrease in grades, while built-up land transformed from cropland and grassland was mainly distributed in low grade of relative elevation, decreasing with increases in grades. The grade of relative elevation where cropland transformed to woodland descended with the implementation of the Grain for Green Project. Our results suggest that it is better to analyze the vertical distribution of land-use conversion with relative elevation classification in hilly regions.
文摘Tropical rainforests are crucial in maintaining about 70% of the world’s plant and animal biodiversity and are also the highest terrestrial carbon reservoir. This study aimed to determine the tree species composition, structure and carbon stocks of the Deng Deng National Park which is a semi-deciduous tropical forest (plots 1 and 2 and the transition zone to the savannah (plot 3). Plots demarcation and enumeration followed standard protocols for permanent monitoring plots. The inventory of tree species ≥ 2 cm revealed a total of 5523 individuals of 64 species in 53 genera belonging to 26 families with plot 2 having the highest (2135 individuals/ha) and plot 3 the least (1291 individuals/ha). Tabernaemontana crassa was the most important tree species in the tropical forest and Lecythis idatimon in the savannah. Basal area was highest in the tropical forest and least in the savannah. The diameter distribution of trees in all forest types displayed a reverse J-pattern. Aboveground biomass was highest in the tropical forest (530.2 ± 66.4 t·C/ha) and least in the savannah (184.3 ± 20.1 t·C/ha). The carbon stock of the above ground biomass was twice as much as that of the below ground biomass, soil organic matter and litter. The total carbon stock estimated in all pools was 278.75 t·C/ha. The study site was poor in plant diversity, biomass and carbon stock, indicating a disturbed site with the absence of large trees and undergoing natural regeneration. This underlines an urgent need for efficient restoration management practices.
文摘We investigate the effect of dopant random fluctuation on threshold voltage and drain current variation in a two-gate nanoscale transistor. We used a quantum-corrected technology computer aided design simulation to run the simulation （10000 randomizations）. With this simulation, we could study the effects of varying the dimensions （length and width）, and thicknesses of oxide and dopant factors of a transistor on the threshold voltage and drain current in subthreshold region （off） and overthreshold （on）. It was found that in the subthreshold region the variability of the drain current and threshold voltage is relatively fixed while in the overthreshold region the variability of the threshold voltage and drain current decreases remarkably, despite the slight reduction of gate voltage diffusion （compared with that of the subthreshold）. These results have been interpreted by using previously reported models for threshold current variability, load displacement, and simple analytical calculations. Scaling analysis shows that the variability of the characteristics of this semiconductor increases as the effects of the short channel increases. Therefore, with a slight increase of length and a reduction of width, oxide thickness, and dopant factor, we could correct the effect of the short channel.
基金Project supported by the National Natural Science Foundations of China (Grant Nos. 10874096 and 20633070)
文摘The above-threshold ionization of argon in an intense 70-fs,400-nm linearly polarized laser pulse has been investigated by the velocity map imaging techniques,combined with an attosecond-resolution quantum wave packet dynamics method.There is a quantitative agreement in all dominant features between the experiment and the theory.Moreover,a peak-splitting phenomenon in the first energy peak has been observed at high pulse intensity.Further,through the theoretical analysis,an ac Stark splitting with evident resonant and nonresonant ionization pathways has been found to be the physical reason for the experimental observations.
文摘A novel high voltage switching circuit with parallel resonant topology is analyzed.Without adding other resonant components,this circuit makes full use of the transformer leakage inductance and winding capacitance so as to reduce the influence of the transformer parasitic parameter.Using device CD4046 to realize the switching control of MOS,this circuit can realize the constant-current charging to capacitor by operating the above resonance.The operating process of the circuit is analyzed,and the power calculation and some practical waveforms are given.
文摘Twenty-six sequences of grades of dryness/wetness and a combined sequence of indexes of winter temperature since A.D. 1471 in China were adopted as our data. The fluctuations of variability of precipitation and mean temperature are statistically significant from analyses. It has been found that in middle latitudes of eastern China the distribution of the relation between mean temperature and interannual variability of precipitation in historical time forms a rather complex regional pattern, and the correlation coefficients are not unique in signs. But the negative correlations are dominant either in extent or in magnitude. The authors provide evidence that Little Ice Age was a time of more frequent extremes and support the idea that the climatic instability is above normal in cool periods.
基金supported by grants from the National High-Tech Research and Development Projects(863)of China(No.2013AA050801)the International S&T Cooperation Projects of China(No.2014DFA60600)
文摘Above ground gas storage devices for compressed air energy storage(CAES) have three types:air storage tanks,gas cylinders,and gas storage pipelines.A cost model of these gas storage devices is established on the basis of whole life cycle cost(LCC) analysis.The optimum parameters of the three types are determined by calculating the theoretical metallic raw material consumption of these three devices and considering the difficulties in manufacture and the influence of gas storage device number.The LCCs of the three types are comprehensively analyzed and compared.The result reveal that the cost of the gas storage pipeline type is lower than that of the other two types.This study may serve as a reference for designing large-scale CAES systems.
基金the project"Mo Yan's Subjective Reconstruction of China and Research on New Literary Tradition"in Major Bidding Projects of the National Social Science Fund of China(17BZW159).
文摘Telling Chinese stories and Chinese experience is an important theme of realist literature in the new era.Chinese writers in the new era face the significant challenge of how to understand the"totality of China"and how to construct the totality spirit and aesthetic character of the"Chinese"narrative.Above Baiyangdian Lake by Guan Renshan takes the historical changes that occurred in the typical environment of Baiyangdian New Area as the content of narration,revealing the growth of people and history and its"Chinese"connotation through the story of the growth of"new character"in the new era.The novel depicts the"rediscovery"and rebirth of history and traditions of China in the new era by"telling stories,"and puts them under a profound context of the past and present and in a broad vision of China and foreign countries,thus constructing the overall aesthetics of realism in contemporary China with an epic grand narrative.The novel artistically shows the building and growth process of China in the new era,and demonstrates its leveraging of resourcesand unique connotation.It is a typical text for understanding the relationshipbetween theimage shaping of China in the new era and Chinese realism literature,as well as the connotation,function and form of Chinese realism.
基金the project Compilation of the Chronicle of Chinese Modern and Contemporary Fiction Theory(1895-2020)and Research on the Reinterpretation and Reconstruction of Classical Resources in Major Bidding Projects of the National Social Science Fund of China(No.22&ZD278).
文摘Above Baiyangdian Lake is a novel set against the backdrop of the great changes in rural China in the new era,revolving around the grand theme of China's contribution to the harmonious development of the world with Chinese wisdom and its solutions.The subject of Above Baiyangdian Lake is grand as it involves politics,culture,economy,and many other aspects.Its publication has reversed the narrowing tendency of Chinese novels in terms of themes and subjects.Above Baiyangdian Lake reconstructs historical time for Chinese modernization with its time consciousness based on a historical perspective.Wang Juexin and Qiao Mai shaped by the writer have contributed to the range of Chinese contemporary literary characters as typical images of the new characters of the era.The value of epic masterpieces like Above Baiyangdian Lake should be fully explored and advocated to provide a useful reference for the development of literature in the newera.
基金the National Social Science Fund of China(ProjectNo.17BZW029).
文摘Above Baiyangdian Lake is a meticulously crafted novel by Guan Renshan nearing a million words in length.The novel offers a panoramic view of everyday life in Baiyangdian Lake and the development of the Xiong'an New Area.The novel exemplifies a genuine sense of the scene by presenting readers with a vivid,authentic depiction of our contemporary life.He employs a narrative structure that overlaps the present with the past,blending tradition and modernity to create a truly magnificent epic.Rather than avoiding the contradictions and darkness inherent to humanity,the novel embraces them and strives to accurately depict their complexity,resulting in a more profound reflection on society.Above Baiyangdian Lake expands and innovates the path of local literature by applying a genuinely realistic approach.It not only surpasses Guan's writing style,but also represents a transcendence of local writing conventions in contemporary literature.It draws upon and elevates the literary tradition of the Hehuadian School,emerging as a notable example of new local writing with distinct regional traits.
文摘Above Baiyangdian Lake is another full-length realistic novel written by Guan Renshan after The Maihe River.In this work,Guan Renshan goes beyond traditional rural writing and artistically narrates the grand landscape of Baiyangdian New Area and the changes of people's fate during its construction.With Guan's refined and mature narrative techniques,the novel clearly shows his ambition to present a“regional epic.”This paper delves into the fictional text and analyzes the structuring method of Above Baiyangdian Lake from multiple perspectives such as its character shaping with historical correspondence,and narrative structure,skills,and style,aiming to provide an approach to interpret the ideological schema of Above Baiyangdian Lake.
基金the financial support from National Natural Science Foundation of China (No. 51707093)。
文摘The degradation of phenol by pulsed discharge plasma above a liquid surface(APDP) and under a liquid surface(UPDP) was compared.The effects of discharge voltage,discharge distance,initial solution conductivity and initial p H on the removal of phenol were studied.It was concluded that the removal of phenol increases with increasing discharge voltage and with decreasing discharge distance in both APDP and UPDP systems.An increase in the initial solution’s conductivity has a positive effect in the APDP system but a negative effect in the UPDP system.In addition,alkaline conditions are conducive to the degradation of phenol in the APDP system,while acidic conditions are conducive in the UPDP system.Free radical quenching experiments revealed that ·O-2has an important influence on the degradation of phenol in the APDP system,while ·OH plays a key role in the UPDP system.This paper verifies the differences in the two discharge methods in terms of phenol removal.
