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1.
We surveyed the forest litter amount at the Lianxiahe watershed in the Three Gorges Reservoir Area and analyzed some hydrological characteristics such as the maximum water-holding capacity and water absorption rate of litter in six types of forests, i.e. the Cupressus funebris forest, the coniferous mixed forest, the coniferous and broad-leaved mixed forest, the broad-leaved forest, the Pinus massoniana forest, the bush forest. Results showed that the litter amount follows the order of the coniferous and broad-leaved mixed forest > the pure C. funebris forest, the P. massoniana forest > the coniferous mixed forest > the broad-leaved forest > the bush forest. The maximal water holding capacity of the undecomposed litter is in the order of the C. funebris forest > the coniferous mixed forest > the bush forest > the coniferous and broad-leaved mixed forest > the broad-leaved forest > the P. massoniana forest. The maximal water-holding capacity of the half-decomposed litter is the P. massoniana forest > the coniferous and broad-leaved mixed forest > the C. funebris forest > the coniferous mixed forest > the broad-leaved forest > the bush forest. In this watershed, the water holding capacity of the litter in the C. funebris forest is the highest, followed by the coniferous mixed forest, coniferous and broad-leaved mixed forest, P. massoniana forest, broad-leaved forest and bush forest. When the soil is covered only by litter, both the maximal rainfall amount and intensity in different forest stands are different if there is no water infiltration and runoff from the ground surface. __________ Translated from Journal of Huazhong Agricultural University, 2005, 27(2): 207–212 [译自: 华中农业大学学报, 2005, 24(2): 207–212]  相似文献   

2.
In order to explore the forest soil physical property in the Three Gorges Reservoir areas, the fractal theory was adopted to study the soil fractal features of the four typical forest stands (mixed Pinus massoniana-broadleaf forests, evergreen broadleaved forests, Phyllostachys pubescens forests and evergreen broadleaved shrub forests) in Jinyun Mountain, Chongqing City, and they were compared with arable land. It has been proposed that the model can be used for the analysis of the relationship between the fractal dimensions and the properties of forest soil. The impacts of fractal dimensions on the soil properties were analyzed with the elasticity analysis and marginal yield analysis. Results showed that the fractal dimension of particle size distribution (PSD), the micro-aggregate size distribution (ASD) and the soil pore size distribution (SPD) can be used as the indices to evaluate the soil structure. In the typical stands of Jinyun Mountain, the fractal dimension of PSD is 2.7–2.9, the ASD is 2.5–2.8, and the SPD is 2.3–2.8. The soil structure of evergreen broadleaved shrub forests performed best in PSD, ASD and SPD, and the soil of P. pubescens forests is the worst. There were some relationships among the PSD, ASD, SPD and some soil properties in the different forests and farmland. The related coefficients are over 0.5. Based on the elasticity analysis and marginal yield analysis, the effect of PSD was more than those of ASD and SPD. Obviously, the further study on the fractal theory application in soil structure and soil properties has important significance. __________ Translated from Science of Soil and Water Conservation, 2006, 4(4): 39–46 [译自: 中国水土保持科学]  相似文献   

3.
The hydrological characteristics of litter in four different forest succession stages, i.e., a Pinus massoniana forest, a mixed conifer and broad-leaved forest with conifer being the dominant species, a mixed conifer and broad-leaved forest with deciduous trees as dominant species, and an evergreen broad-leaved forest, have been studied by means of substituting space for time. The results show that while a community is developing to a zonal climax, the amount of litter becomes larger and its decomposition intensity becomes stronger; there is a positive relation between its water-holding capacity and velocity and its community maturity for the half-decomposed litter layer. __________ Translated from Journal of Central South University of Forestry and Technology, 2007, 27(6): 38–43 [译自: 中南林业科技大学学报]  相似文献   

4.
三峡库区典型森林植被类型对坡面产流影响   总被引:1,自引:0,他引:1  
在一定地形地貌基础上,植被与降水是决定坡面产流、产沙量的主要因素.2005~2006年对重庆缙云山4个天然林地径流场和农地径流场进行定位观测,结果表明:①森林植被在一定范围内对坡面径流量有削减作用,前期降雨对坡面径流有影响;②坡面径流峰值与暴雨峰值呈一一对应关系,马尾松和常绿阔叶林的变化幅度较小,楠竹林和常绿阔叶灌丛变化较大;③地下径流深与降雨量呈一一对应关系,地下径流深与降雨量关系反映出前期降雨对地下径流量的影响;④马尾松阔叶混交林、常绿阔叶林和常绿阔叶冠丛地下径流峰值的总体趋势是随降雨强度的增加而增加;楠竹林和农地随降雨强度的增加而呈下降趋势.  相似文献   

5.
氮沉降背景下毛竹向常绿阔叶林扩张问题是当前我国亚热带区域面临的主要生态问题与研究热点之一.以毛竹、竹阔混交林及常绿阔叶林为对象,通过1 a的氮添加试验,分析毛竹与常绿阔叶林木在不同植被类型中生长的差异,以探究氮沉降对不同植被类型中毛竹与常绿阔叶林木生长的影响.结果 显示:(1)竹阔混交林中毛竹的平均胸径增长量、平均单株...  相似文献   

6.
By using random amplified polymorphic DNA (RAPD) technique, this paper studied the genetic diversity and genetic differentiation of Lithocarpus harlandii populations in three forest communities (coniferous forest, coniferous and broad-leaved mixed forest, and evergreen broad-leaved forest) with different succession stages in Tiantai Mountain in Zhejiang Province. The results showed that a total of 173 repetitive loci were produced in 60 individuals of L. harlandii by 12 random primers, among which, 152 loci were polymorphic, and the total percentage of polymorphic loci was 87.86%. The average percentage of polymorphic loci of the populations was 65.32%, and their total genetic diversity estimated by Shannon information index was 0.4529, with an average of 0.3458, while that judged from Nei’s index was 0.3004, with an average of 0.2320. The percentage of polymorphic loci, Shannon information index, and Nei’s index of the populations were in the sequence of coniferous forest community > coniferous and broad-leaved mixed forest community > evergreen broad-leaved forest community. Analysis of molecular variance (AMOVA) showed that 72.85% of genetic variance was found within the populations, and 27.15% of genetic variance resided among the populations. The coefficient of gene diferentiation was 0.2277, and the gene flow was 1.6949. The genetic structure of L. harlandii was influenced not only by the biological characteristics of this species, but also by the microenvironment of different communities. The mean of genetic identity among three populations of L. harlandii was 0.8662, and the mean of their genetic distance was 0.1442. The genetic similarity between coniferous and broad-leaved mixed forest community and evergreen broad-leaved forest community was the highest, while that between evergreen broad-leaved forest community and coniferous forest community was the lowest. The unweighted pair group method with arithmeticmean (UPGMA) cluster analysis based on Nei’s genetic distance showed that conierous and broad-leaved mixed forest community first gathered with evergreen broad-leaved forest community, and then with coniferous forest community. __________ Translated from Chinese Journal of Ecology, 2007, 26(4): 509–514 [译自: 生态学杂志]  相似文献   

7.
Spearman rank-correlation analysis and grey relational grade analysis were used to study infiltration characteristics of water in different forest soils in the Simian mountains, Chongqing City. The results indicate that the soil bulk density, contents of coarse sand, and porosity of macropores were significantly correlated with saturated hydraulic conductivity. Porosity of macropores and contents of coarse sand were positively correlated with soil saturated hydraulic conductivity and soil bulk density negatively. Based on the initial infiltration rate, the stable infiltration rate, time required for infiltration to reach a stable state, and cumulative infiltration, all of which are crucial parameters determining soil infiltration capacity, the results of grey relational grade analysis showed that the grey relational grades of the different forest soils were listed from high to low as broad-leaved forest (0.8031) > Phyllostachys pubescens forest (0.7869) > mixed conifer-broadleaf forest (0.4454) > coniferous forest (0.4039). Broadleaf forest had the best ability to be infiltrated among the four soils studied. The square roots of the coefficients of determination obtained from fitting the Horton infiltration equation, simulated in our study of forest soils, were higher than 0.950.We conclude that soils of broad-leaved forests were the best suited for infiltration processes of forestry in the Simian mountains. __________ Translated from Journal of Soil and Water Conservation, 2008, 22(4): 95–99 [译自: 水土保持学报]  相似文献   

8.
文章采用建径流小区定位观测方法,对富源县云南松次生林、华山松人工林、针阔混交林、次生灌丛和荒草地等主要植物群落进行水土保持能力的观测。分析表明:富源县的降雨量主要集中于5~10月,雨季降雨量占全年的86.48%,且降雨量主要是10mm以上的降雨产生;不同群落地表径流量、土壤流失量和侵蚀降雨次数依次均为荒草地>次生灌丛>云南松次生林>华山松人工林>针阔混交林,说明森林植被类型中针阔混交林保土保水能力最强,其次是纯林,在低效林改造和生态建设工程中应大面积推广混交林的营建。  相似文献   

9.
In order to understand the relationship between population succession and its genetic behavior, random amplified polymorphic DNA (RAPD) technique was used to analyze the genetic diversity of Quercu glandulifera var. brevipetiolata populations in three forest communities with different succession stages (coniferous forest, coniferous and broad-leaved mixed forest, evergreen broad-leaved forest). The results showed that 145 repetitive loci were produced in 60 individuals of Q. glandulifera using 11 primers, among which 120 loci were polymorphic, and the total percentage of polymorphic loci was 82.76% with an average of 64.14%. Estimated by the Shannon information index, the total genetic diversity of the three populations was 0.4747, with an average of 0.3642, while it was 0.3234, with an average of 0.2484, judged from the Nei index. Judged from percentage of polymorphic loci, Shannon inform at ion index and Nei index, the genetic diversity followed a decreasing order: coniferous forest > broad-leaved mixed forest > evergreen broad-leaved forest. Analysis of molecular variance (AMOVA) showed that 69.73% of the genetic variance existed within populations and 30.27% of the genetic variance existed among populations. The coefficient of gene differentiation (GST) was 0.2319 and the gene flow (N m) was 1.6539. The mean of genetic identity among populations of Q. glandulifera was 0.8501 and the mean of genetic distance was 0.1626. The genetic identity between the Q. glandulifera population in the coniferous forest and that in the coniferous and broadleaved mixed forest was the highest. UPGMA cluster analysis based on Nei’s genetic distance showed that the population in the coniferous forest gathered with that in the coniferous and broad-leaved mixed forest firstly, then with that in the evergreen broad-leaved forest. The genetic structure of Q. glandulifera was not only characteristic of the biological characteristics of this species, but was also influenced by the microenvironment in different communities. __________ Translated from Journal of Northwest Forestry University, 2008, 23(1): 18–22 [译自: 西北林学院学报]  相似文献   

10.
滇中华山松人工林的水文特征及水量平衡   总被引:21,自引:1,他引:21       下载免费PDF全文
根据滇中高原的华山松林集水区径流场连续 3a的降雨和径流观测数据 ,进行了华山松人工林的水文特征及水量平衡的研究。结果表明 :( 1)本区域降水量的季节分配不均 ,湿季 ( 6~ 10月 )降水量占全年的 80 % ,降水量主要由大于 10mm以上的降雨带来 ,且降雨强度大部分小于 5.0mm·h- 1。 ( 2 )集水区年平均降雨量 10 0 5.6mm ,在林冠作用面降雨量的分配中 ,林冠截留雨量 2 10 .6mm ,截留率 2 0 .9% ;穿透过林冠层的降雨 74 5.3mm ,树干茎流量 4 9.7mm ,分别占降雨量的 74 .2 %和 4 .9%。 ( 3)集水区径流的月变化滞后于降雨 ,总径流量 172 .2 9mm ,总径流系数 17.13% ,其中 ,地表径流 8.0 3mm ,地下径流 164.2 6mm ;地表径流主要集中在雨季产生 ,一次性降雨对地表径流的影响显著 (R =0 .91)。 ( 4 )土壤蓄水年变化量 11.2mm ,约占年降水量的 1.1% ,但月变化较大 ;系统水量最大的输出是蒸散 ,每年以气态形式返回大气的水量 82 2 .1mm ,占降水量的 81.8% ;在蒸散的水量中 ,林冠截留雨量的直接物理蒸发量 2 10 .6mm ,占总蒸散量的 2 5.6%。  相似文献   

11.
广州市酸雨对不同森林冠层淋溶规律的研究   总被引:20,自引:2,他引:20       下载免费PDF全文
1998年4月至1999年3月对广州市白云山马尾松林和常绿阔叶林、广州市龙眼洞马尾松林两试验点进行了酸雨的监测,并测定和分析了林内穿透雨物理量及化学量,旨在探讨酸雨对不同森林冠层养分淋溶规律的影响。结果表明:(1)广州市酸雨占次数的79.7%或占降雨量的95.1%。(2)酸雨通过林冠层后,pH值明显增加。(3)在马尾松林和常绿阔叶林中,某些单次降雨出现SO4^2-、NO3^-、NH4^+Al^3+、Na^+的负淋溶现象,说明森林对这些离子(特别是NO3^-、Aa^3+)具有吸收作用;阔叶林全年的NO3^-和Al^3+净淋溶为负值,说明阔叶林比马尾松林对这两种离子具有更强的吸收能力。(4)雨水酸度增加(即pH值减小),明显提高阳离子Ca^2+、Mg^2+、K^+和Na^+冠层淋溶面分率。(5)NH4^+、SO4^  相似文献   

12.
According to fixed-position data for 1985–2003 from nine runoff plots of Caijiachuan watershed which lies in Jixian County of Shanxi Province in Loess area, this paper studied the relationship between vegetation and runoff and sediment production in sloping lands in detail, which helps to provide scientific basis for vegetation re-construction and studies on environmental transformation of water and sediment in watersheds of Loess area. Although, many study results testify that forest vegetation has an important function in soil and water conservation and cutting runoff, the effect of vegetation on runoff and sediment transmission is complicated, and this needs to be studied in depth. The results of the paper showed the following. Firstly, the natural secondary forest performs better function of soil and water conservation than artificial Robinia pseudoacacia forest, and runoff and sediment produced in the former in individual rainfall were 65%–82% and 23%–92% of those produced in the latter. At the same time, better correlative relationship between runoff and sediment production and rainfall and rainfall intensity were testified by multiple regression, but the correlation decreased gradually with the increase of canopy density of forest. Secondly, the difference of runoff and sediment production in several land use types was very distinct, and the amount of runoff and sediment produced from Ostryopsis davidiana forest and natural secondary forest were the least, and runoff and sediment produced from in artificial Robinia pseudoacacia forest and Pinus tabulaeformis forest were 5-fold as much as those from O. davidiana forest. Besides, runoff and sediment produced in mixed planting of apple trees and crops were 16.14-fold and 2.96-fold than those of O. davidiana forest, respectively, but the amount decreased obviously after high-standard soil preparation in the case of the former. Thirdly, based on gray cognate analyses of factors affecting runoff and sediment production in sloping land, the factors of stand canopy density and herb and litter biomass were the most significant ones, whose gray incidence degree exceeded 0.6. Therefore, mixed forest with multi-layer stand structure and shrub forest should be developed in vegetation re-construction of Loess area, which will help to increase coverage and litter thickness in order to cut down the runoff and sediment dramatically in sloping land. __________ Translated from Chinese Journal of Applied Ecology, 2005, 16(9): 1,613–1,617 [译自: 应用生态学报, 2005, 16(9): 1,613–1,617]  相似文献   

13.
The composition and structure of five natural secondary forests in Shenzhen were studied based on data of plots and were compared with Hong Kong zonal forest, so as to detect their succession stage and species diversity level. According to succession process of subtropical forest and ecological characteristics of dominant species, the authors speculate that five communities are at different stages. Sinosideroxylon community dominated by heliophilous evergreen broad-leaved tree (Sinosideroxylon wightianum) and conifer tree (Pinus massoniana) is at the third stage. Itea Acronychia community dominated by two evergreen broad-leaved heliophytes (Itea chinensis and Acronychia pedunculata) is at the fourth stage. The others, i.e., Schefflera,Sterculia and Cleistocalyx Sterculia community are at the fifth stage where some mesophytes are dominant but heliophytes have a weighed percentage of importance value. Due to succession stage and different forest management and conservation models, the species diversity of five communities is significantly lower than that of Endospermum community in Hong Kong. The values of Shannon-Wiener index and Pielous evenness index of five communities are 2.04-2.953 and 64.2%-74% respectively, but those of the Endospermum community are 4.74 and 79% respectively. The current situation of these communities suggests that the necessary measures should be taken to protect and restore the communities.  相似文献   

14.
In order to investigate the effect of invastion by pine wood nematode (PWN), this study analyzed severalfunctional indices, i.e., the increment in DBH and stand volume and biomass, in the damaqed stands with various mixedpercentages of Pinus massoniana and P. thunbergii and with different levels of damage. According to the results of rate of change in increment of DBH and stand volume, the forest ecosystem resistance against PWN increased with a reduct on n the m xed ratio of pine. The resistance was highest with a mixed percentage of 50%. The invasion of PWN hanged the corresponding relationship of increment between DBH and stand volume (pure stands 〉 7:3 conifer and roadleaf 〉 6:4 conifer and broadleaf 〉 5:5 conifer and broadleaf) among the P. thunbergii stands when there is no amage, but for P. massoniana stands this phenomenon did not occur. For the increment rate of DBH and stand volume, is significant change in P, thunbergii forest indicates that the resistance of pure P. thunbergii forest was higher than at of P. massoniana. The invasion of PWN accelerates the succession from pure stands to mixed stands and then tohe broadleaf evergreen stands.  相似文献   

15.
长江三峡重庆库区不同植被条件下土壤抗冲性研究   总被引:2,自引:0,他引:2  
以长江三峡重庆库区典型针阔混交林、常绿阔叶林、毛竹林、灌木林及农地(对照)为研究对象,通过室内放水冲刷试验,分析探讨了森林表层与亚表层土壤的抗冲时间特性和坡度效应。结果表明:土壤抗冲性随冲刷时间延长而增强,表层土壤抗冲性为前5 min抗冲指数变化最为剧烈,亚表层土壤抗冲性为前3 min抗冲指数变化最为剧烈,典型林地土壤抗冲指数随时间变化特征为幂函数关系;林地土壤抗冲指数与坡度关系为xK e0.0755 0.0755,农地土壤抗冲性受坡度影响最为强烈,竹林土壤抗冲性受坡度影响最小;农地较林地土壤抗冲性明显降低,林地中,针阔混交林土壤抗冲性最强,森林有较好的抵抗土壤冲刷的作用。  相似文献   

16.
鼎湖山亚热带季风常绿阔叶林蒸散研究   总被引:14,自引:1,他引:14  
运用Penman蒸散力公式和理论上导上导出的计算森林生态系统蒸散公式,对亚热睦带性群落鼎湖山季风常绿阔叶林的蒸散力和蒸散逐日进行计算,其结果表明:鼎湖山季风常绿阔叶林蒸散力年平均为987.5mm占同期降雨量的47%,蒸散力最大的月分是7月,最小的月份是2月,这样基本上与近地面层的气温度变化规律相一致,而与同期的降雨量有所延迟。林外自由水面蒸发年平均为1194.5mm干季林内蒸散力明显小于林外自由水面的蒸发,而湿季两者又十分接近,因此,两者相比可用来作为该地区划分干湿季的一个参指标,理论公式法所计算出该系统的蒸散年平均为951.9mm,与蒸散力相当,占同期降雨量的45.3%。鼎湖山季风常绿阔叶林总径流量年平均为1103.8mm,径流系数为0.52,研究期间系统贮水量的变经年平均为38.9mm.水量平均法所得的蒸散年平均为960.1mm与公式法计算所得的蒸散非常接近,3年的系统误差不到15,因此,初步得出此公式是计算森林生态系统蒸散的一种值得推广的方法。  相似文献   

17.
The Mn, Zn and Cu contents of litter, soil fauna and soil in Pinus koraiensis and mixed broad-leaved forest in Liangshui Nature Reserve of Xiaoxing’an Mountains were analyzed in this paper, results showed that the tested microelement contents in the litter, soil fauna and soil followed the order: Mn>Zn>Cu, but varied with environmental components, for Mn the order is soil>litter>soil fauna, for Zn is soil fauna>litter and soil, and for Cu is soil fauna>soil>litter. The change range of the tested microelement contents in litter was larger in broad-leaved forest than those in coniferous forest. Different soil fauna differed in their microelementenrichment capability, the highest content of Mn, Zn and Cu existed in earthworm, centipede and diplopod, respectively. The contents of the tested microelements in soil fauna had significant correlations with their environmental background values, litter decomposition rate, food habit of soil fauna, and its absorbing selectively and enrichment to microelements. The microelements contained in 5–20 cm soil horizon were more than those in 0–5 cm humus layer, and their dynamics differed in various horizons. __________ Translated from Chinese Journal of Applied Ecology, 2007, 18(2): 277–282 [译自: 应用生态学报]  相似文献   

18.
Patterns of litterfall and nutrient input in a subtropical evergreen broad-leaved forest in northern Okinawa, Japan, were studied during May, 1996–April, 1999. The mean annual rate of litterfall in the five sampling plots ranged from 6.84 to 8.93 Mg ha−1 yr−1, of which 63.3–68.5% were leaves; 22.4–29.1% woody parts (including branches < 5.0 cm in diameter and bark); 2.8–5.0% sexual organs and 4.6–6.3% miscellaneous material. Significant differences were found among plots and among years. Significantly monthly differences pronounced seasonal patterns in litterfall were observed. Total litterfall and leaf litter showed negative correlations with relative basal area of the dominant species,Castanopsis sieboldii; and showed positive correlations with mean height of the stands. The dominant species,C. sieboldii produced an average of 2.36 Mg ha−1 yr−1 of leaf litter, which covered 30.5% of the annual litter production, and the nutrient input from those litterfall contributed 32.3, 28.3, 30.2, 22.2, 32.5, and 30.5% of total N, P, K, Ca, Mg, and Na, respectively. Nutrient use efficiency in litter production was high, especially for P and K compared with other broad-leaved forests in Japan indicating that P and K may be limiting in Okinawan evergreen broad-leaved forest.  相似文献   

19.
Agroforestry trees are now well known to play a central role in the build up of nutrients pools and their transformations similar to that of forest ecosystem, however, information on the potential of homegarden trees accumulating and releasing nitrogen (mineralization) is lacking. The present study reports seasonal variations in pool sizes of mineral N (NH4+-N and NO3-N), and net N-mineralization rate in relation to rainfall and temperature under coconut (Cocos nucifera L.), clove (Eugenia caryophyllata Thunb) and nutmeg (Myristica fragrans Houtt. Nees) trees in a coconut-spice trees plantation for two annual cycles in the equatorial humid climate of South Andaman Island of India. Concentration of NH4+-N was the highest during wet season (May–October) and the lowest during post-wet season (November–January) under all the tree species. On the contrary, concentration of NO3-N was the lowest in the wet season and the highest during the post-wet season. However, concentrations of the mineral N were the highest under the nutmeg and the lowest under the coconut trees. Like the pool sizes, mean annual mineralization was the highest under the nutmeg (561 mg kg−1 yr−1) and the lowest under the coconut trees (393 mg kg−1 yr−1). Rate of mineralization was the highest during the post-wet season and the lowest during the dry season (February–April) under all the tree species. High rainfall during the wet season, however, reduced the rate of nitrification under all the tree species. The mean annual mineralization was logarithmically related with rainfall amount and mean monthly temperature.  相似文献   

20.
A virgin Pinus koraiensis forest in the Xiaoxing’an Mountains was selected to study its rainfall redistribution effect via 97 rainfall occurrences during a growing season. The following results were obtained: 1) The canopy interception of the P. koraiensis virgin forest amounted to 98168 mm during a growing season (May to September), which was 19.6 per cent of the total rainfall and 1.3 times that of a secondary Betula platyphylla forest. Compared with other forest types in China (11.4%–36.5%), the ratio of the canopy interception in the virgin pine forest was at a medium level. 2) The throughfall of the virgin pine forest was 395.77 mm, which accounted for 78.7% of total precipitation, and the stem-flow was 8.78 mm, accounting for 1.74% of total precipitation. Compared with the secondary birch forest, the virgin pine forest had lower throughfall but higher stem-flow. 3) Cubic regression equations (p < 0.01) which describe the relation between throughfall, stem-flow and canopy interception in the virgin pine forest and rainfall in an open field were fitted. A linear regression equation (p < 0.01) was found to be a better fit for the relationship between throughfall of the secondary birch forest and rainfall outside the forest. Factors affecting throughfall and stem-flow were analyzed, with results providing a good reference to the study of rainfall redistribution in coniferous and broadleaved mixed forests. __________ Translated from Science of Soil and Water Conservation, 2006, 4(6): 61–65 [译自: 中国水土保持科学]  相似文献   

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