This study aims to evaluate the solar and wind energy potential across Razavi Khorasan Province,Iran,with a specific focus on the Khaf region.A preliminary assessment of mean solar radiation,mean wind speeds,and Weibu...This study aims to evaluate the solar and wind energy potential across Razavi Khorasan Province,Iran,with a specific focus on the Khaf region.A preliminary assessment of mean solar radiation,mean wind speeds,and Weibull distribution parameters was conducted for different towns and zones within the province.The findings showed that Khaf has favorable characteristics for further analysis.The solar and wind energy metrics examined include global horizontal irradiance,clearness index,wind rose patterns,and turbulence intensity.At a height of 40 m,Khaf’s wind power density reached 1650 W/m^(2),indicating exceptional wind energy generation potential.Additionally,Khaf received an average annual solar radiation of 2046 kW·h/m^(2),representing significant solar energy potential.Harnessing these substantial renewable resources in Khaf could allow Razavi Khorasan Province to reduce reliance on fossil fuels,improve energy sustainability,and mitigate climate change impacts.This research contributes an in-depth assessment of Razavi Khorasan's solar and wind energy potential,particularly for the promising Khaf region.Further work may examine optimal sites for renewable energy projects and grid integration strategies to leverage these resources.展开更多
A study of the interfacial behavior and internal thermal stress distribution in fiber-reinforced composites is essential to assess their performance and reliability.CNT/carbon fiber(CF)hybrid fibers were constructed u...A study of the interfacial behavior and internal thermal stress distribution in fiber-reinforced composites is essential to assess their performance and reliability.CNT/carbon fiber(CF)hybrid fibers were constructed using electrophoretic deposition.The interfacial properties of CF/epoxy and CNT/CF/epoxy composites were statistically investigated and compared using in-situ thermal Raman mapping by dispersing CNTs as a Raman sensing medium(CNT_(R))in a resin.The associated local thermal stress changes can be simulated by capturing the G'band position distribution of CNT_(R) in the epoxy at different temperatures.It was found that the G'band shifted to lower positions with increasing temperature,reaching a maximum difference of 2.43 cm^(−1) at 100℃.The interfacial bonding between CNT/CF and the matrix and the stress distribution and changes during heat treatment(20-100℃)were investig-ated in detail.This work is important for studying thermal stress in fiber-reinforced composites by in-situ thermal Raman mapping technology.展开更多
Background,aim,and scope Soil saturated hydraulic conductivity(K_(s))is a key parameter in the hydrological cycle of soil;however,we have very limited understanding of K_(s)characteristics and the factors that inf lue...Background,aim,and scope Soil saturated hydraulic conductivity(K_(s))is a key parameter in the hydrological cycle of soil;however,we have very limited understanding of K_(s)characteristics and the factors that inf luence this key parameter in the Mu Us sandy land(MUSL).Quantifying the impact of changes in land use in the Mu Us sandy land on K_(s)will provide a key foundation for understanding the regional water cycle,but will also provide a scientific basis for the governance of the MUSL.Materials and methods In this study,we determined K_(s)and the basic physical and chemical properties of soil(i.e.,organic matter,bulk density,and soil particle composition)within the first 100 cm layer of four different land use patterns(farmland,tree,shrub,and grassland)in the MUSL.The vertical variation of K_(s)and the factors that influence this key parameter were analyzed and a transfer function for estimating K_(s)was established based on a multiple stepwise regression model.Results The K_(s)of farmland,tree,and shrub increased gradually with soil depth while that of grassland remained unchanged.The K_(s)of the four patterns of land use were moderately variable;mean K_(s)values were ranked as follows:grassland(1.38 mm·min^(-1))<tree(1.76 mm·min^(-1))<farmland(1.82 mm·min^(-1))<shrub(3.30 mm·min^(-1)).The correlation between K_(s)and organic matter,bulk density,and soil particle composition,varied across different land use patterns.A multiple stepwise regression model showed that silt,coarse sand,bulk density,and organic matter,were key predictive factors for the K_(s)of farmland,tree,shrub,and grassland,in the MUSL.Discussion The vertical distribution trend for K_(s)in farmland is known to be predominantly influenced by cultivation,fertilization,and other factors.The general aim is to improve the water-holding capacity of shallow soil on farmland(0-30 cm in depth)to conserve water and nutrients;research has shown that the K_(s)of farmland increases with soil depth.The root growth of tree and shrub in sandy land exerts mechanical force on the soil due to biophysical processes involving rhizospheres,thus leading to a significant change in K_(s).We found that shallow high-density fine roots increased the volume of soil pores and eliminated large pores,thus resulting in a reduction in shallow K_(s).Therefore,the K_(s)of tree and shrub increased with soil depth.Analysis also showed that the K_(s)of grassland did not change significantly and exhibited the lowest mean value when compared to other land use patterns.This finding was predominantly due to the shallow root system of grasslands and because this land use pattern is not subject to human activities such as cultivation and fertilization;consequently,there was no significant change in K_(s)with depth;grassland also had the lowest mean K_(s).We also established a transfer function for K_(s)for different land use patterns in the MUSL.However,the predictive factors for K_(s)in different land use patterns are known to be affected by soil cultivation methods,vegetation restoration modes,the distribution of soil moisture,and other factors,thus resulting in key differences.Therefore,when using the transfer function to predict K_(s)in other areas,it will be necessary to perform parameter calibration and further verification.Conclusions In the MUSL,the K_(s)of farmland,tree,and shrub gradually increased with soil depth;however,the K_(s)of grassland showed no significant variation in terms of vertical distribution.The mean K_(s)values of different land use patterns were ranked as follows:shrub>farmland>tree>grassland;all land use patterns showed moderate levels of variability.The K_(s)for different land use patterns exhibited differing degrees of correlation with soil physical and chemical properties;of these,clay,silt,sand,bulk density,and organic matter,were identified as important variables for predicting K_(s)in farmland,tree,shrub,and grassland,respectively.Recommendations and perspectives In this study,we used a stepwise multiple regression model to establish a transfer function prediction model for K_(s)for different land use patterns;this model possessed high estimation accuracy.The ability to predict K_(s)in the MUSL is very important in terms of the conservation of water and nutrients.展开更多
以三种评价方法考察设抽油烟机的封闭厨房内燃烧废气系统污染扩散的规律,分析灶具的安装位置、排烟机高度范围及运行档位对废气系统扩散的影响。运用 Data Fit 拟合实验数据,建立废气系统的浓度扩散和?及总?强度分布的数学模型,利用 VC+...以三种评价方法考察设抽油烟机的封闭厨房内燃烧废气系统污染扩散的规律,分析灶具的安装位置、排烟机高度范围及运行档位对废气系统扩散的影响。运用 Data Fit 拟合实验数据,建立废气系统的浓度扩散和?及总?强度分布的数学模型,利用 VC++可视化编程技术,对模拟结果与实际测试结果进行比较。得出 CO2和 CO 浓度、?扩散模拟规律图表;废气扩散热、浓度总?强度变化图表、实测数据图表、模拟与实测比较图表。厨房废气系统扩散有其规律性和方向性,用 VC++编程对厨房液化气燃烧废气系统的总?强度进行数值模拟反映总污染传播的规律性是可行的。展开更多
From March to May, 2004, we selected 8 typical parks or green lands in Shanghai downtown as the study sites to conduct a ornithological research. During this study, total 55 species of birds were recorded, which inclu...From March to May, 2004, we selected 8 typical parks or green lands in Shanghai downtown as the study sites to conduct a ornithological research. During this study, total 55 species of birds were recorded, which included 31 resident and 24 migratory species. With statistics methodology, we analyzed the avian communities with 10 major environmental factors covering the park area, water percentage, vegetation species, canopy cover, shrub cover, grass cover, hill number, location condition, human quantity, path width, the study results indicated that: (1) the following 7 environmental factors were important to impact the structures of the avian community, they were park area, vegetation species, shrub coverage, grass coverage, hill number, location condition of the parks and path width; (2) the avian community of theses urban parks tended to deteriorate in the bird number and diversity; the man-made lake which was currently promoted in the park designing and planning process would not be good to attract the birds.展开更多
[Objective]The aim was to reveal the spatial distribution characteristics of total nutrients in soil and provide a theoretical basis for farmland management and improvement of crop yield. [Method]GIS technique was use...[Objective]The aim was to reveal the spatial distribution characteristics of total nutrients in soil and provide a theoretical basis for farmland management and improvement of crop yield. [Method]GIS technique was used to analyze the spatial distribution characteristics of total C,total N,total P and total K for different soil layers in Liaoning Province. [Result]The results showed that the content of total C,total N,total P decrease from east to west,but the content of total K was high in north district of Liaoning Province. The content of total C,total N,total P and total K was higher in soil surface (0-20 cm) than the lower (20-40 cm). Total K varied less with soil depth,and its mean content was respectively 17.64 g/kg and 17.08 g/kg for soil surface and soil lower layer. [Conclusion]The results of the distribution of soil total nutrients in different soil layers supplied a theory basis for farmland management.展开更多
Igneous rocks in the South China Sea have broad prospects for oil and gas exploration.Integrated geophysical methods are important approaches to study the distribution of igneous rocks and to determine and identify ig...Igneous rocks in the South China Sea have broad prospects for oil and gas exploration.Integrated geophysical methods are important approaches to study the distribution of igneous rocks and to determine and identify igneous rock bodies.Aimed at the characteristics of gravity and magnetic fields in the South China Sea,several potential field processing methods are preferentially selected.Reduction to the pole by variable inclinations in the area of low magnetic latitudes is used to perform reduction processing on magnetic anomalies.The preferential continuation method is used to separate gravity and magnetic anomalies and extract the gravity and magnetic anomaly information of igneous rocks in the shallow part of the South China Sea.The 3D spatial equivalent distribution of igneous rocks in South China Sea is illustrated by the 3 D correlation imaging of magnetic anomalies.Since the local anomaly boundaries are highlighted gravity and magnetic gradients,the distribution characters of different igneous rocks are roughly outlined by gravity and magnetic correlation analysis weighted by gradient.The results show the distribution of igneous rocks is controlled and influenced by deep crustal structure and faulting.展开更多
Eupatorium adenophorum Spreng. was introduced in Yunnan Province of China around 1940. Since then it has been spreading rapidly, particularly in the southern and southwestern parts of China and caused serious economic...Eupatorium adenophorum Spreng. was introduced in Yunnan Province of China around 1940. Since then it has been spreading rapidly, particularly in the southern and southwestern parts of China and caused serious economic loss. The biological research and inte-grated control on E. adenophorum were carried out from 1980's in Yunnan Province. Together with other 15 invasive external species, the weed has been listed in the White Paper by The State Environmental Protection Administration of China. This paper briefly reviews the studies on natural distribution, biological character, ecological character, chemical component, hazard, potential application and the control of E. adenophorum. The research direction for this invasive external species in future was also discussed.展开更多
The spatial distribution and population dynamics of Quercus liaotungensis Koidz., Fraxinus rhynchophylla Hance and Acer mono Maxim. were studied in three warm temperate deciduous forests in Dongling Mountain, Beijing....The spatial distribution and population dynamics of Quercus liaotungensis Koidz., Fraxinus rhynchophylla Hance and Acer mono Maxim. were studied in three warm temperate deciduous forests in Dongling Mountain, Beijing. Clumped distributions appeared in most seedlings (≤0.4 m), short saplings (0.4-1 m) and tall saplings (1-2 m). Random distributions appeared in adults of Q. liaotungensis in Plot 1, F. rhynchophylla in Plot 3. The LSD method was used to discern the differences of different aged population. The class distribution of Q. liaotungensis was nearly a reverse-J shape for Plot 1 and Plot 3, suggesting that the population regenerates continuously. The age-structures of F. rhynchophylla and A. mono in Plot 1 and the test results indicated that they would increase continuously. In Plot 2, the class distribution and the test results showed that all populations would not regenerate continuously.展开更多
An improved Carnegie Ames Stanford Approach model (CASA model) was used to estimate the net primary productivity (NPP) of the Northeast China Transect (NECT) every month from 1982 to 2000. The spatial-temporal d...An improved Carnegie Ames Stanford Approach model (CASA model) was used to estimate the net primary productivity (NPP) of the Northeast China Transect (NECT) every month from 1982 to 2000. The spatial-temporal distribution of NPP along NECT and its response to climatic change were also analyzed. Results showed that the change tendency of NPP spatial distribution in NECT is quite similar to that of precipitation and their spatial correlation coefficient is up to 0.84 (P 〈 0.01). The inter-annual variation of NPP in NECT is mainly affected by the change of the aestival NPP every year, which accounts for 67.6% of the inter-annual increase in NPP and their spatial correlation coefficient is 0.95 (P 〈 0.01). The NPP in NECT is mainly cumulated between May and September, which accounts for 89.8% of the annual NPP. The NPP in summer (June to August) accounts for 65.9% of the annual NPP and is the lowest in winter. Recent climate changes have enhanced plant growth in NECT. The mean NPP increased 14.3% from 1980s to 1990s. The inter-annual linear trend of NPP is 4.6 gC·m^-2·a^-1, and the relative trend is 1.17%, which owns mainly to the increasing temperature.展开更多
[Objective] To compare the translocation and distribution of imidacloprid in tobacco with spray and root irrigation application methods. [Methods] Pot experiment in the greenhouse was carried out, and LC-MSMS was used...[Objective] To compare the translocation and distribution of imidacloprid in tobacco with spray and root irrigation application methods. [Methods] Pot experiment in the greenhouse was carried out, and LC-MSMS was used to determine the con- tent of imidacloprid in different parts of tobacco plants (roots, stems, the upper, middle and lower leaves) at different time. [Results] The imidacloprid could be absorbed by root and could be transported to all parts of the tobacco plant after irrigating root, but the original deposition amount was larger and the transport efficiency was lower after spraying. [Conclusion] The translocation and distribution of imidacloprid by spraying was more uniform and the holding efficiency was better, but imidacloprid with root irrigation could act on leaf directly, and had better readily availability.展开更多
High gradient magnetic separation was conducted in order to separate insoluble zinc ferrite from zinc calcine before acid leaching of hydrometallurgical process. Chemical composition and structural characterization of...High gradient magnetic separation was conducted in order to separate insoluble zinc ferrite from zinc calcine before acid leaching of hydrometallurgical process. Chemical composition and structural characterization of zinc calcine were studied via inductively coupled plasma (ICP), X-ray diffraction (XRD), Mossbauer spectra, scanning electron microscopy (SEM) and laser particle analysis (LPA). The parameters of magnetic separation which affect the distribution of zinc ferrite and undesired elements, such as calcium, sulfur and lead in magnetic concentrate were investigated. The results of high gradient magnetic separation indicate that more than 85% of zinc ferrite is distributed into magnetic concentrate from the zinc calcine under the magnetic induction of 0.70 T. In addition, about 60% of calcium and 40% of sulfur distribute in non magnetic phases of tailings during magnetic separation process. Most of lead distributes uniformly along the zinc calcine in superfine particle size.展开更多
Glyptosternoid fishes are a group of sisorid catfishes living in torrents of rivers mainly originating from the Qinghai-Tibet Plateau. Based on our survey in the Drung River Basin, seven collecting sites were investig...Glyptosternoid fishes are a group of sisorid catfishes living in torrents of rivers mainly originating from the Qinghai-Tibet Plateau. Based on our survey in the Drung River Basin, seven collecting sites were investigated and 271 glyptosternoid fishes caught belong to three species (Pareuchiloglanis kamengensis, Exostoma labiatum and Oreoglanis mocropterus). Features of the distribution of the three catfishes were assessed. More individuals of E. labiatum were caught in the lower reaches of the Drung River with fast water velocity and it might be more adapted to a torrent habitat. The relationships between standard length (L) and weight (W) for P. kamengensis, E. labiatum and O. macropterus were also studied, and the parameter b of the L-W relationship (W = aL^b) ranged between 2. 8201 and 3. 0131. From the present study, all the three catfish species grow allometrically and the growth type of E. labiatum is the closest to a symmetrical one.展开更多
The γ/γ' microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy (SEM),transmission electron microscopy (TEM) and scanning tra...The γ/γ' microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy (SEM),transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM).The crystals were grown by the floating zone (FZ) method.Both cuboidal and spherical γ' precipitates were formed after a two-step aging.The size of the cuboidal γ' phases first increased and then decreased with the extension of the second-step aging time.Re,Co and Cr strongly concentrated in the γ phase whereas Ni and Al enriched in the γ' phase.Thermodynamic calculation by JMatPro was performed to explain the experimental observations.展开更多
Currently, it is difficult for people to express signal information simultaneously in the time and frequency domains when analyzing acoustic logging signals using a simple-time or frequency-domain method. It is diffic...Currently, it is difficult for people to express signal information simultaneously in the time and frequency domains when analyzing acoustic logging signals using a simple-time or frequency-domain method. It is difficult to use a single type of time-frequency analysis method, which affects the feasibility of acoustic logging signal analysis. In order to solve these problems, in this paper, a fractional Fourier transform and smooth pseudo Wigner Ville distribution (SPWD) were combined and used to analyze array acoustic logging signals. The time-frequency distribution of signals with the variation of orders of fractional Fourier transform was obtained, and the characteristics of the time-frequency distribution of different reservoirs under different orders were summarized. Because of the rotational characteristics of the fractional Fourier transform, the rotation speed of the cross terms was faster than those of primary waves, shear waves, Stoneley waves, and pseudo Rayleigh waves. By choosing different orders for different reservoirs according to the actual circumstances, the cross terms were separated from the four kinds of waves. In this manner, we could extract reservoir information by studying the characteristics of partial waves. Actual logging data showed that the method outlined in this paper greatly weakened cross-term interference and enhanced the ability to identify partial wave signals.展开更多
The attenuation of seismic signals is often characterized in the frequency domain using statistical measures of the power spectrum. However, the conventional Fourier transform-based power spectrum estimation methods s...The attenuation of seismic signals is often characterized in the frequency domain using statistical measures of the power spectrum. However, the conventional Fourier transform-based power spectrum estimation methods suffer from time-frequency resolution problems. Wigner-Ville distribution, which is a member of Cohen class time-frequency distributions, possesses many appealing properties, such as time-frequency marginal distribution, time-frequency localization, etc. Therefore, Wigner-Ville distribution offers a new way for estimating the attenuation of seismic signals. This paper initially gives a brief introduction to Wigner-Ville distribution and the smoothed Wigner-Ville distribution that is effective in reducing the cross-term effect, and then presents a method for seismic attenuation estimation based on the instantaneous energy spectrum of the Wigner-Ville distribution. A real data example from central Tarim Basin in western China is presented to illustrate the effectiveness of the proposed method. The results show that the Wigner-Ville distribution-based seismic attenuation estimation method can effectively detect the difference between reef, shoal and lagoon facies by their attenuation properties, indicating that the estimated seismic attenuation can be used for reef and shoal carbonate reservoir characterization.展开更多
Faeces were counted along horizontal, 5.0m wide strips at altitude intervals of 100m to examine the altitudinal ranging pattern of a band of black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Nanren (99...Faeces were counted along horizontal, 5.0m wide strips at altitude intervals of 100m to examine the altitudinal ranging pattern of a band of black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Nanren (99°04′E, 28°34′N, Baima Snow Mountain Nature Reverse, Yunnan, China) at four areas in each season between 2000-2001. Faeces were also counted along vertical, 2.5 m wide strips in one subvalley and on one subridge in each area. Monkeys used an altitudinal range of 3500-4300m, but preferred occupying the upper forest belt between 3900 and 4200m asl year-round, being at the highest altitude in summer, the lowest altitude in spring, and middle altitudes between autumn and winter (lower in winter than autumn). Moreover, there were secondary peaks of lower altitude use (3700m) in spring and winter. In addition, more faeces were distributed in subvalleys than on subridges in winter, this suggests that monkeys tend to spend more time in subvalleys where there is less wind and fluctuating temperatures. The significant correlation between faecal density and lichen load might indicate that altitudinal distribution of food resources may act as an important factor affecting the monkeys' range. The monkeys might migrate to lower altitudes to eat young sprouts and leaves in spring, and to shelter from snowstorms in winter, possibly resulting in the secondary peaks at lower altitudes.展开更多
文摘This study aims to evaluate the solar and wind energy potential across Razavi Khorasan Province,Iran,with a specific focus on the Khaf region.A preliminary assessment of mean solar radiation,mean wind speeds,and Weibull distribution parameters was conducted for different towns and zones within the province.The findings showed that Khaf has favorable characteristics for further analysis.The solar and wind energy metrics examined include global horizontal irradiance,clearness index,wind rose patterns,and turbulence intensity.At a height of 40 m,Khaf’s wind power density reached 1650 W/m^(2),indicating exceptional wind energy generation potential.Additionally,Khaf received an average annual solar radiation of 2046 kW·h/m^(2),representing significant solar energy potential.Harnessing these substantial renewable resources in Khaf could allow Razavi Khorasan Province to reduce reliance on fossil fuels,improve energy sustainability,and mitigate climate change impacts.This research contributes an in-depth assessment of Razavi Khorasan's solar and wind energy potential,particularly for the promising Khaf region.Further work may examine optimal sites for renewable energy projects and grid integration strategies to leverage these resources.
文摘A study of the interfacial behavior and internal thermal stress distribution in fiber-reinforced composites is essential to assess their performance and reliability.CNT/carbon fiber(CF)hybrid fibers were constructed using electrophoretic deposition.The interfacial properties of CF/epoxy and CNT/CF/epoxy composites were statistically investigated and compared using in-situ thermal Raman mapping by dispersing CNTs as a Raman sensing medium(CNT_(R))in a resin.The associated local thermal stress changes can be simulated by capturing the G'band position distribution of CNT_(R) in the epoxy at different temperatures.It was found that the G'band shifted to lower positions with increasing temperature,reaching a maximum difference of 2.43 cm^(−1) at 100℃.The interfacial bonding between CNT/CF and the matrix and the stress distribution and changes during heat treatment(20-100℃)were investig-ated in detail.This work is important for studying thermal stress in fiber-reinforced composites by in-situ thermal Raman mapping technology.
文摘Background,aim,and scope Soil saturated hydraulic conductivity(K_(s))is a key parameter in the hydrological cycle of soil;however,we have very limited understanding of K_(s)characteristics and the factors that inf luence this key parameter in the Mu Us sandy land(MUSL).Quantifying the impact of changes in land use in the Mu Us sandy land on K_(s)will provide a key foundation for understanding the regional water cycle,but will also provide a scientific basis for the governance of the MUSL.Materials and methods In this study,we determined K_(s)and the basic physical and chemical properties of soil(i.e.,organic matter,bulk density,and soil particle composition)within the first 100 cm layer of four different land use patterns(farmland,tree,shrub,and grassland)in the MUSL.The vertical variation of K_(s)and the factors that influence this key parameter were analyzed and a transfer function for estimating K_(s)was established based on a multiple stepwise regression model.Results The K_(s)of farmland,tree,and shrub increased gradually with soil depth while that of grassland remained unchanged.The K_(s)of the four patterns of land use were moderately variable;mean K_(s)values were ranked as follows:grassland(1.38 mm·min^(-1))<tree(1.76 mm·min^(-1))<farmland(1.82 mm·min^(-1))<shrub(3.30 mm·min^(-1)).The correlation between K_(s)and organic matter,bulk density,and soil particle composition,varied across different land use patterns.A multiple stepwise regression model showed that silt,coarse sand,bulk density,and organic matter,were key predictive factors for the K_(s)of farmland,tree,shrub,and grassland,in the MUSL.Discussion The vertical distribution trend for K_(s)in farmland is known to be predominantly influenced by cultivation,fertilization,and other factors.The general aim is to improve the water-holding capacity of shallow soil on farmland(0-30 cm in depth)to conserve water and nutrients;research has shown that the K_(s)of farmland increases with soil depth.The root growth of tree and shrub in sandy land exerts mechanical force on the soil due to biophysical processes involving rhizospheres,thus leading to a significant change in K_(s).We found that shallow high-density fine roots increased the volume of soil pores and eliminated large pores,thus resulting in a reduction in shallow K_(s).Therefore,the K_(s)of tree and shrub increased with soil depth.Analysis also showed that the K_(s)of grassland did not change significantly and exhibited the lowest mean value when compared to other land use patterns.This finding was predominantly due to the shallow root system of grasslands and because this land use pattern is not subject to human activities such as cultivation and fertilization;consequently,there was no significant change in K_(s)with depth;grassland also had the lowest mean K_(s).We also established a transfer function for K_(s)for different land use patterns in the MUSL.However,the predictive factors for K_(s)in different land use patterns are known to be affected by soil cultivation methods,vegetation restoration modes,the distribution of soil moisture,and other factors,thus resulting in key differences.Therefore,when using the transfer function to predict K_(s)in other areas,it will be necessary to perform parameter calibration and further verification.Conclusions In the MUSL,the K_(s)of farmland,tree,and shrub gradually increased with soil depth;however,the K_(s)of grassland showed no significant variation in terms of vertical distribution.The mean K_(s)values of different land use patterns were ranked as follows:shrub>farmland>tree>grassland;all land use patterns showed moderate levels of variability.The K_(s)for different land use patterns exhibited differing degrees of correlation with soil physical and chemical properties;of these,clay,silt,sand,bulk density,and organic matter,were identified as important variables for predicting K_(s)in farmland,tree,shrub,and grassland,respectively.Recommendations and perspectives In this study,we used a stepwise multiple regression model to establish a transfer function prediction model for K_(s)for different land use patterns;this model possessed high estimation accuracy.The ability to predict K_(s)in the MUSL is very important in terms of the conservation of water and nutrients.
文摘以三种评价方法考察设抽油烟机的封闭厨房内燃烧废气系统污染扩散的规律,分析灶具的安装位置、排烟机高度范围及运行档位对废气系统扩散的影响。运用 Data Fit 拟合实验数据,建立废气系统的浓度扩散和?及总?强度分布的数学模型,利用 VC++可视化编程技术,对模拟结果与实际测试结果进行比较。得出 CO2和 CO 浓度、?扩散模拟规律图表;废气扩散热、浓度总?强度变化图表、实测数据图表、模拟与实测比较图表。厨房废气系统扩散有其规律性和方向性,用 VC++编程对厨房液化气燃烧废气系统的总?强度进行数值模拟反映总污染传播的规律性是可行的。
文摘From March to May, 2004, we selected 8 typical parks or green lands in Shanghai downtown as the study sites to conduct a ornithological research. During this study, total 55 species of birds were recorded, which included 31 resident and 24 migratory species. With statistics methodology, we analyzed the avian communities with 10 major environmental factors covering the park area, water percentage, vegetation species, canopy cover, shrub cover, grass cover, hill number, location condition, human quantity, path width, the study results indicated that: (1) the following 7 environmental factors were important to impact the structures of the avian community, they were park area, vegetation species, shrub coverage, grass coverage, hill number, location condition of the parks and path width; (2) the avian community of theses urban parks tended to deteriorate in the bird number and diversity; the man-made lake which was currently promoted in the park designing and planning process would not be good to attract the birds.
基金Supported by Public Project of Science and Technology Ministry(SYKYYW200903)The Ecological Carrying Capacity and Region Ecological Security Regulation of Northeast Industrial Base(2004CB418507)~~
文摘[Objective]The aim was to reveal the spatial distribution characteristics of total nutrients in soil and provide a theoretical basis for farmland management and improvement of crop yield. [Method]GIS technique was used to analyze the spatial distribution characteristics of total C,total N,total P and total K for different soil layers in Liaoning Province. [Result]The results showed that the content of total C,total N,total P decrease from east to west,but the content of total K was high in north district of Liaoning Province. The content of total C,total N,total P and total K was higher in soil surface (0-20 cm) than the lower (20-40 cm). Total K varied less with soil depth,and its mean content was respectively 17.64 g/kg and 17.08 g/kg for soil surface and soil lower layer. [Conclusion]The results of the distribution of soil total nutrients in different soil layers supplied a theory basis for farmland management.
基金the National 863 Projects(Nos.2006AA06Z111,2006AA06201-3,and 2006AA09A101-3)National Special Project(No.SinoProbe-01-05)Open Project of the National Key Laboratory for Geological Processes and Mineral Resources(No.GPMR0942).
文摘Igneous rocks in the South China Sea have broad prospects for oil and gas exploration.Integrated geophysical methods are important approaches to study the distribution of igneous rocks and to determine and identify igneous rock bodies.Aimed at the characteristics of gravity and magnetic fields in the South China Sea,several potential field processing methods are preferentially selected.Reduction to the pole by variable inclinations in the area of low magnetic latitudes is used to perform reduction processing on magnetic anomalies.The preferential continuation method is used to separate gravity and magnetic anomalies and extract the gravity and magnetic anomaly information of igneous rocks in the shallow part of the South China Sea.The 3D spatial equivalent distribution of igneous rocks in South China Sea is illustrated by the 3 D correlation imaging of magnetic anomalies.Since the local anomaly boundaries are highlighted gravity and magnetic gradients,the distribution characters of different igneous rocks are roughly outlined by gravity and magnetic correlation analysis weighted by gradient.The results show the distribution of igneous rocks is controlled and influenced by deep crustal structure and faulting.
基金This study was supported by Project of Chinese Academy of Science Knowledge Innovation Program (KSCX1-SW-13-0X-0X) and National Natural Science Foundation of China (30470337)
文摘Eupatorium adenophorum Spreng. was introduced in Yunnan Province of China around 1940. Since then it has been spreading rapidly, particularly in the southern and southwestern parts of China and caused serious economic loss. The biological research and inte-grated control on E. adenophorum were carried out from 1980's in Yunnan Province. Together with other 15 invasive external species, the weed has been listed in the White Paper by The State Environmental Protection Administration of China. This paper briefly reviews the studies on natural distribution, biological character, ecological character, chemical component, hazard, potential application and the control of E. adenophorum. The research direction for this invasive external species in future was also discussed.
文摘The spatial distribution and population dynamics of Quercus liaotungensis Koidz., Fraxinus rhynchophylla Hance and Acer mono Maxim. were studied in three warm temperate deciduous forests in Dongling Mountain, Beijing. Clumped distributions appeared in most seedlings (≤0.4 m), short saplings (0.4-1 m) and tall saplings (1-2 m). Random distributions appeared in adults of Q. liaotungensis in Plot 1, F. rhynchophylla in Plot 3. The LSD method was used to discern the differences of different aged population. The class distribution of Q. liaotungensis was nearly a reverse-J shape for Plot 1 and Plot 3, suggesting that the population regenerates continuously. The age-structures of F. rhynchophylla and A. mono in Plot 1 and the test results indicated that they would increase continuously. In Plot 2, the class distribution and the test results showed that all populations would not regenerate continuously.
基金This paper was supported by the National Natural Sci-ence Foundation of China (Grant No. 40371001) and the Youth Foundation of Beijing Normal University
文摘An improved Carnegie Ames Stanford Approach model (CASA model) was used to estimate the net primary productivity (NPP) of the Northeast China Transect (NECT) every month from 1982 to 2000. The spatial-temporal distribution of NPP along NECT and its response to climatic change were also analyzed. Results showed that the change tendency of NPP spatial distribution in NECT is quite similar to that of precipitation and their spatial correlation coefficient is up to 0.84 (P 〈 0.01). The inter-annual variation of NPP in NECT is mainly affected by the change of the aestival NPP every year, which accounts for 67.6% of the inter-annual increase in NPP and their spatial correlation coefficient is 0.95 (P 〈 0.01). The NPP in NECT is mainly cumulated between May and September, which accounts for 89.8% of the annual NPP. The NPP in summer (June to August) accounts for 65.9% of the annual NPP and is the lowest in winter. Recent climate changes have enhanced plant growth in NECT. The mean NPP increased 14.3% from 1980s to 1990s. The inter-annual linear trend of NPP is 4.6 gC·m^-2·a^-1, and the relative trend is 1.17%, which owns mainly to the increasing temperature.
基金Supported by the Key Science and Technology Project of Jinlin Tobacco Industrial Co.,Ltd.(JS-2015-07)the Scientific and Technological Innovation Project of Chinese Academy of Agricultural Sciences(ASTIP-TRIC06)~~
文摘[Objective] To compare the translocation and distribution of imidacloprid in tobacco with spray and root irrigation application methods. [Methods] Pot experiment in the greenhouse was carried out, and LC-MSMS was used to determine the con- tent of imidacloprid in different parts of tobacco plants (roots, stems, the upper, middle and lower leaves) at different time. [Results] The imidacloprid could be absorbed by root and could be transported to all parts of the tobacco plant after irrigating root, but the original deposition amount was larger and the transport efficiency was lower after spraying. [Conclusion] The translocation and distribution of imidacloprid by spraying was more uniform and the holding efficiency was better, but imidacloprid with root irrigation could act on leaf directly, and had better readily availability.
基金Project (2011AA061001) supported by the High-tech Research and Development Program of ChinaProject (50830301) supported by the National Natural Science Foundation of China+1 种基金Project (50925417) supported by National Science Fund for Distinguished Young Scientists, ChinaProject (2012BAC12102) supported by the National "Twelfth Five-year" Plan for Science and Technology Support, China
文摘High gradient magnetic separation was conducted in order to separate insoluble zinc ferrite from zinc calcine before acid leaching of hydrometallurgical process. Chemical composition and structural characterization of zinc calcine were studied via inductively coupled plasma (ICP), X-ray diffraction (XRD), Mossbauer spectra, scanning electron microscopy (SEM) and laser particle analysis (LPA). The parameters of magnetic separation which affect the distribution of zinc ferrite and undesired elements, such as calcium, sulfur and lead in magnetic concentrate were investigated. The results of high gradient magnetic separation indicate that more than 85% of zinc ferrite is distributed into magnetic concentrate from the zinc calcine under the magnetic induction of 0.70 T. In addition, about 60% of calcium and 40% of sulfur distribute in non magnetic phases of tailings during magnetic separation process. Most of lead distributes uniformly along the zinc calcine in superfine particle size.
文摘Glyptosternoid fishes are a group of sisorid catfishes living in torrents of rivers mainly originating from the Qinghai-Tibet Plateau. Based on our survey in the Drung River Basin, seven collecting sites were investigated and 271 glyptosternoid fishes caught belong to three species (Pareuchiloglanis kamengensis, Exostoma labiatum and Oreoglanis mocropterus). Features of the distribution of the three catfishes were assessed. More individuals of E. labiatum were caught in the lower reaches of the Drung River with fast water velocity and it might be more adapted to a torrent habitat. The relationships between standard length (L) and weight (W) for P. kamengensis, E. labiatum and O. macropterus were also studied, and the parameter b of the L-W relationship (W = aL^b) ranged between 2. 8201 and 3. 0131. From the present study, all the three catfish species grow allometrically and the growth type of E. labiatum is the closest to a symmetrical one.
基金Project(08dj1400402) supported by the Major Program for the Fundamental Research of Science and Technology Committee of the Shanghai Municipality,ChinaProject(09ZZ16) supported by Innovation Program of Shanghai Municipal Education Committee,China
文摘The γ/γ' microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy (SEM),transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM).The crystals were grown by the floating zone (FZ) method.Both cuboidal and spherical γ' precipitates were formed after a two-step aging.The size of the cuboidal γ' phases first increased and then decreased with the extension of the second-step aging time.Re,Co and Cr strongly concentrated in the γ phase whereas Ni and Al enriched in the γ' phase.Thermodynamic calculation by JMatPro was performed to explain the experimental observations.
基金supported by National Natural Science Foundation of China(Grant No.40874059)
文摘Currently, it is difficult for people to express signal information simultaneously in the time and frequency domains when analyzing acoustic logging signals using a simple-time or frequency-domain method. It is difficult to use a single type of time-frequency analysis method, which affects the feasibility of acoustic logging signal analysis. In order to solve these problems, in this paper, a fractional Fourier transform and smooth pseudo Wigner Ville distribution (SPWD) were combined and used to analyze array acoustic logging signals. The time-frequency distribution of signals with the variation of orders of fractional Fourier transform was obtained, and the characteristics of the time-frequency distribution of different reservoirs under different orders were summarized. Because of the rotational characteristics of the fractional Fourier transform, the rotation speed of the cross terms was faster than those of primary waves, shear waves, Stoneley waves, and pseudo Rayleigh waves. By choosing different orders for different reservoirs according to the actual circumstances, the cross terms were separated from the four kinds of waves. In this manner, we could extract reservoir information by studying the characteristics of partial waves. Actual logging data showed that the method outlined in this paper greatly weakened cross-term interference and enhanced the ability to identify partial wave signals.
文摘The attenuation of seismic signals is often characterized in the frequency domain using statistical measures of the power spectrum. However, the conventional Fourier transform-based power spectrum estimation methods suffer from time-frequency resolution problems. Wigner-Ville distribution, which is a member of Cohen class time-frequency distributions, possesses many appealing properties, such as time-frequency marginal distribution, time-frequency localization, etc. Therefore, Wigner-Ville distribution offers a new way for estimating the attenuation of seismic signals. This paper initially gives a brief introduction to Wigner-Ville distribution and the smoothed Wigner-Ville distribution that is effective in reducing the cross-term effect, and then presents a method for seismic attenuation estimation based on the instantaneous energy spectrum of the Wigner-Ville distribution. A real data example from central Tarim Basin in western China is presented to illustrate the effectiveness of the proposed method. The results show that the Wigner-Ville distribution-based seismic attenuation estimation method can effectively detect the difference between reef, shoal and lagoon facies by their attenuation properties, indicating that the estimated seismic attenuation can be used for reef and shoal carbonate reservoir characterization.
基金Doctoral Research Startup Grant at Southwest Forestry CollegeThe Chinese Academy of Science(KSCX2-1-03)
文摘Faeces were counted along horizontal, 5.0m wide strips at altitude intervals of 100m to examine the altitudinal ranging pattern of a band of black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Nanren (99°04′E, 28°34′N, Baima Snow Mountain Nature Reverse, Yunnan, China) at four areas in each season between 2000-2001. Faeces were also counted along vertical, 2.5 m wide strips in one subvalley and on one subridge in each area. Monkeys used an altitudinal range of 3500-4300m, but preferred occupying the upper forest belt between 3900 and 4200m asl year-round, being at the highest altitude in summer, the lowest altitude in spring, and middle altitudes between autumn and winter (lower in winter than autumn). Moreover, there were secondary peaks of lower altitude use (3700m) in spring and winter. In addition, more faeces were distributed in subvalleys than on subridges in winter, this suggests that monkeys tend to spend more time in subvalleys where there is less wind and fluctuating temperatures. The significant correlation between faecal density and lichen load might indicate that altitudinal distribution of food resources may act as an important factor affecting the monkeys' range. The monkeys might migrate to lower altitudes to eat young sprouts and leaves in spring, and to shelter from snowstorms in winter, possibly resulting in the secondary peaks at lower altitudes.