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Effects of Land Use Patterns on Soil Heavy Metal Contents 被引量:23
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作者 孙亚乔 钱会 +1 位作者 段磊 杨胜科 《Agricultural Science & Technology》 CAS 2010年第1期159-162,共4页
Through sampling in farmland and analysis in laboratory,the contents and the pollution level of Cr,Cu,As,Pb,Zn in different soils were studied. The comparative result showed that the As in all soil samples are lower t... Through sampling in farmland and analysis in laboratory,the contents and the pollution level of Cr,Cu,As,Pb,Zn in different soils were studied. The comparative result showed that the As in all soil samples are lower than the mean value of Shaanxi and whole nation,the Cr in lower half soil samples are higher than the mean value of Shaanxi and whole nation,the Cu and Zn in majority soil samples are higher than the mean value of Shaanxi and whole nation,and the Pb in all soil samples is higher than the mean value of Shaanxi and whole nation. The single factor pollution index and multi-factor pollution index method were used to evaluate the soil pollution. According to Soil Environmental Quality Standard,the studied soils were at unpolluted degrees,the soils were clear,the quality of soil adapt to the crop growth,and not affect the quality of agricultural product. 展开更多
关键词 Farmland soil Heavy metal Content characteristics Qinling piedmont
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Seismic analysis of the active character of the Taihang Mountain piedmont fault 被引量:4
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作者 徐明才 高景华 +2 位作者 荣立新 王广科 王小江 《Applied Geophysics》 SCIE CSCD 2010年第4期392-398,401,共8页
The Taihang Mountain piedmont fault is a large-scale structure zone in north and east China which cross Beijing,with the NE-NNE extent spans approximately 620 km.It is very important to determine the fault zone activi... The Taihang Mountain piedmont fault is a large-scale structure zone in north and east China which cross Beijing,with the NE-NNE extent spans approximately 620 km.It is very important to determine the fault zone activity due to the close relation of active structures and earthquakes.Regarding the fault activity,there are three different opinions:1) it is a large deep fault zone;2) it is an active fault zone and an earthquake structure belt;and 3) it is not an earthquake structure belt.In order to ascertain the active character of the fault,the deep tectonic setting and the activity since the Quaternary were investigated using recent seismic and drilling data to make a joint interpretation.The investigation results show that the Taihang Mountain piedmont fault is not a large lithospheric fault because the early middle Pleistocene(Q(P2)) layers are offset by the fault and the late middle Pleistocene(Q(P2)) and late Pleistocene layers are not offset by the fault.We determine that the Taihang Mountain piedmont fault in the area is not an active fault and is also not a large lithospheric fault.This study result provides important geological and geophysical data for city planning and construction in Hebei province and, especially,has great significance for seismic hazard assessment of the capital area. 展开更多
关键词 Taihang Mountain piedmont fault active fault seismic exploration drilling borehole verification
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皮埃蒙特肉牛三元杂交研究 被引量:3
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作者 唐中伟 程之渊 唐朝忠 《山西农业大学学报(自然科学版)》 CAS 2010年第6期524-527,共4页
用皮埃蒙特牛的冷冻精液进行人工授精,改良西门塔尔杂种母牛和晋南母牛,杂交试验,以期为皮埃蒙特肉牛杂交改良利用、提高高档牛肉的生产,提供科学的数据。试验结果表明,皮埃蒙特三元杂种公犊牛初生重、6月龄重、18月龄重分别是36.2 kg、... 用皮埃蒙特牛的冷冻精液进行人工授精,改良西门塔尔杂种母牛和晋南母牛,杂交试验,以期为皮埃蒙特肉牛杂交改良利用、提高高档牛肉的生产,提供科学的数据。试验结果表明,皮埃蒙特三元杂种公犊牛初生重、6月龄重、18月龄重分别是36.2 kg、182.3 kg和542.2 kg,育肥期12~18月龄平均日增重1079 g。屠宰率为61.4%,净肉率为52.3%,眼肌面积102 cm2。皮晋牛屠宰率为59%,净肉率50.4%,眼肌面积84 cm2。育肥屠宰试验结果表明,皮西杂组合杂交改良效果明显。 展开更多
关键词 三元杂交 肉牛 皮埃蒙特
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皮埃蒙特杂种肉牛生长激素基因型与体重、日增重的相关性研究 被引量:3
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作者 孙少华 李雪梅 +2 位作者 魏学蕊 李玉 常泽军 《黄牛杂志》 2001年第4期8-11,共4页
本研究利用 PCR- RFLPs标记技术 ,对 63头杂种肉牛的生长激素基因的第 5外显子和 3’端区域进行了分析研究 ,发现 Hae 酶切位点具有多态性 ,并分为三种基因型( AA、BB和 AB)。通过构建最小二乘线性模型 ,分析了生长激素基因型与杂种肉... 本研究利用 PCR- RFLPs标记技术 ,对 63头杂种肉牛的生长激素基因的第 5外显子和 3’端区域进行了分析研究 ,发现 Hae 酶切位点具有多态性 ,并分为三种基因型( AA、BB和 AB)。通过构建最小二乘线性模型 ,分析了生长激素基因型与杂种肉牛高于1 2月龄体重和 6~ 1 2月龄日增重的关系。结果表明 :生长激素 AB基因型的效应稍高于AA、BB型 。 展开更多
关键词 肉牛 生长激素基因型 PCR-RFLPS 线性模型 生产性能
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Hurricane disturbances, tree diversity, and succession in North Carolina Piedmont forests, USA 被引量:5
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作者 Weimin Xi Robert K.Peet +1 位作者 Michael T.Lee Dean L.Urban 《Journal of Forestry Research》 SCIE CAS CSCD 2019年第1期219-231,共13页
Windthrow plays a critical role in maintaining species diversity in temperate forests. Do large-scale strong wind events(i.e., tropical cyclones, including hurricanes,typhoons and severe cyclonic storms) increase tree... Windthrow plays a critical role in maintaining species diversity in temperate forests. Do large-scale strong wind events(i.e., tropical cyclones, including hurricanes,typhoons and severe cyclonic storms) increase tree diversity in severely damaged forest areas? Do hurricanes(tropical cyclones that occurs in the Atlantic Ocean and northeastern Pacific Ocean) lead to altered relative abundance of shade-tolerant and shade-intolerant species? Did historic hurricanes alter the succession trajectory of the damaged forests? We used nearly 70-year tree demographic data to assess the effects of two major hurricanes on woody species diversity in Piedmont forests, North Carolina, USA. Species richness(S) and Shannon–Wiener's diversity index(H') were used to evaluate the changes in tree diversity. The changes in composition were assessed with Nonmetric Multidimensional Scaling. The pre-hurricane successional phase can strongly influence both the damage severity and subsequent responses. Although there is often an immediate drop in diversity following a hurricane, understory tree diversity quickly increases to levels that exceed those prior to the disturbance. This leads to an increase in diversity in stands that were substantially damaged. Hurricanes significantly decrease the dominance of shade-intolerant canopy species while increasing preestablished, more shade-tolerant species. We conclude that large, and infrequent hurricanes help to maintain local tree diversity, but also accelerate the increase in dominance of understory species such as red maple and beech. 展开更多
关键词 Wind DISTURBANCE Tree species diversity Plant SUCCESSION Disturbance-diversity relationship PIEDMONT FORESTS
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Late Pleistocene-Holocene slip history of the Langshan-Seertengshan piedmont fault(Inner Mongolia,northern China) from cosmogenic ^(10)Be dating on a bedrock fault scarp 被引量:12
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作者 SHEN Xiao-ming LI De-wen +3 位作者 TIAN Yun-tao LV Yan-wu LI Da-wei LI Yan-feng 《Journal of Mountain Science》 SCIE CSCD 2016年第5期882-890,共9页
Offset geomorphic features and deformed late Quaternary strata indicate active deformation along the Langshan-Seertengshan piedmont fault (LSPF), one of the most active faults in the Hetao fault zone in Inner Mongol... Offset geomorphic features and deformed late Quaternary strata indicate active deformation along the Langshan-Seertengshan piedmont fault (LSPF), one of the most active faults in the Hetao fault zone in Inner Mongolia, North China. The widespread occurrence of bedrock fault scarps along the LSPF offers excellent opportunity to examine the faulting history. Using cosmogenic ^10Be exposure dating, we measured the exposure ages of the western Langshankou scarp, located in the middle segment of the LSPF. Our data revealed at least two earthquakes that occurred at 22.2±3.3 Ira and 7.2±2.4 ka, respectively. These events are consistent with previous paleoseismic trench studies. The regression of the relationship between the age and sampling height along the scarp yield a fault slip rate of 0.10 ±0.05/-0.06 mm/yr, which is significantly lower than the average post-late Pleistocene fault slip rate of ~1 mm/yr, as estimated from the offset of the T2 terraces by previous studies. This indicates that the slip of the LSPF may have been accommodated by other fault branches. 展开更多
关键词 Lanshan-Seertengshan piedmont fault(LSPF) Fault scarp Cosmogenic nuclide Exposureage Fault slip rate
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Late Quaternary Activity of the Huashan Piedmont Fault and Associated Hazards in the Southeastern Weihe Graben,Central China 被引量:3
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作者 DU Jianjun LI Dunpeng +1 位作者 WANG Yufang MA Yinsheng 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第1期76-92,共17页
The Weihe Graben is not only an important Cenozoic fault basin in China but also a significant active seismic zone. The Huashan piedmont fault is an important active fault on the southeast side of the Weihe Graben and... The Weihe Graben is not only an important Cenozoic fault basin in China but also a significant active seismic zone. The Huashan piedmont fault is an important active fault on the southeast side of the Weihe Graben and has been highly active since the Cenozoic. The well–known Great Huaxian County Earthquake of 1556 occurred on the Huashan piedmont fault. This earthquake, which claimed the lives of approximately 830000 people, is one of the few large earthquakes known to have occurred on a high–angle normal fault. The Huashan piedmont fault is a typical active normal fault that can be used to study tectonic activity and the associated hazards. In this study, the types and characteristics of late Quaternary deformation along this fault are discussed from geological investigations, historical research and comprehensive analysis. On the basis of its characteristics and activity, the fault can be divided into three sections, namely eastern, central and western. The eastern and western sections display normal slip. Intense deformation has occurred along the two sections during the Quaternary; however, no deformation has occurred during the Holocene. The central section has experienced significant high–angle normal fault activity during the Quaternary, including the Holocene. Holocene alluvial fans and loess cut by the fault have been identified at the mouths of many stream valleys of the Huashan Mountains along the central section of the Huashan piedmont fault zone. Of the three sections of the Huashan piedmont fault, the central section is the most active and was very active during the late Quaternary. The rate of normal dip–slip was 1.67–2.71±0.11 mm/a in the Holocene and 0.61±0.15 mm/a during the Mid–Late Pleistocene. As is typical of normal faults, the late Quaternary activity of the Huashan piedmont fault has produced a set of disasters, which include frequent earthquakes, collapses, landslides, mudslides and ground fissures. Ground fissures mainly occur on the hanging–wall of the Huashan piedmont fault, with landslides, collapses and mudslides occurring on the footwall. 展开更多
关键词 Weihe Graben Huashan piedmont fault late Quaternary fault–related hazards normal fault
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Assessment of Groundwater Source of Piedmont Plain Area of China Northwest Arid Region Based On Numerical Modeling 被引量:1
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作者 HOU Xianhua ZHANG Jiahao LIU Jilai 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第S1期419-420,共2页
After the middle of 1960s,along with the appearance and extensive utilization of computer featured in large capacity and rapid speed,numerical method(mainly include finite difference method and finite element
关键词 groundwater source numerical simulation piedmont plain area Xiangride-Ruomuhong Qaidam Basin
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皮埃蒙特牛改良南阳牛遗传育种研究进展 被引量:10
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作者 张秋菊 《中国牛业科学》 2020年第6期17-19,共3页
为了研究皮埃蒙特牛改良南阳牛遗传育种研究进展,本文综述了皮埃蒙特牛杂交改良南阳牛的历史进程,皮埃蒙特牛改良南阳牛杂交后代繁殖性能研究,皮埃蒙特牛改良南阳牛杂交后代肉用性能研究,并提出了产业化集群开发的合理化建议。
关键词 皮埃蒙特牛 南阳牛 遗传育种 研究进展
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Study on crustal deformation of the Ms6.6 Damxungearthquake in 2008 by InSAR measurements 被引量:1
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作者 Xuejun Qiao Shanjun Ren Zhaosheng Nie Yu Zhou Qiang Shen Shaomin Yang 《Geodesy and Geodynamics》 2010年第1期15-22,共8页
Three Envisat images from ESA were used to derive the pre - and co-seismic deformation interfereograms caused by the Damxung Ms6. 6 earthquake of Oct. 6,2008 ,by using InSAR. The result shows no significant crustal mo... Three Envisat images from ESA were used to derive the pre - and co-seismic deformation interfereograms caused by the Damxung Ms6. 6 earthquake of Oct. 6,2008 ,by using InSAR. The result shows no significant crustal motion more than 4 months before the earthquake, but a maximum co-seismic displacement of about 0.3 m in an epicentral area of 20 km × 20 km. The deformation field was symmetrically distributed about a NS axis, where the west side subsided and the east side uplifted. We used a linear elastic dislocation model in half space and a nonlinear constraint optimized algorithm to estimate the slip distribution along the fault. The results indicates that the epicenter is located at 90. 374°E ,29. 745°N with a moment magnitude of Mw6. 35. The earthquake is dominated by normal faulting with a maximum slip of 3 m on a 12 km × 11 km fault plane striking S189°W,dipping 60° to NW at a depth of 9.5 km,and is located at a sub-fault of the southeastern Piedmont of the Nyainqentanglha mountains. The relatively shallow depth of earthquake is related to relatively high heat flow in the area. 展开更多
关键词 InSAR (synthetic aperture radar interferometry) co-seismic deformation Damxung Yadong-Gulu rift southeastern Piedmont of the Nyainqentanglha mountains
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Experimental study on unsaturated soil water diffusivity in different soils in Hebei Piedmont Plain 被引量:1
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作者 GAO Ye-xin LIU Ji-chao +2 位作者 FENG Xin ZHANG Ying-ping ZHANG Bing 《Journal of Groundwater Science and Engineering》 2019年第2期165-172,共8页
Horizontal soil column method was used to determine the horizontal diffusion rate of sandy loam, loam and clay loam under the same bulk density. The results showed that the migration rates of different lithological we... Horizontal soil column method was used to determine the horizontal diffusion rate of sandy loam, loam and clay loam under the same bulk density. The results showed that the migration rates of different lithological wet fronts were different. The sandy loam had the fastest migration rate, the loam followed, and the clay loam was the slowest, but the law of change is the same among the three lithologies. The volumetric water content affects the change of Boltzmann parameter λ. When the volumetric water content is between 0.35-0.45 cm^3/cm^3,λ approaches stability. When the volumetric water content is less than 0.35 cm^3/cm^3, the λ value decreases rapidly with the decrease of water content. The water diffusion rate is related to the volumetric water content and particle size. The greater the moisture content is, the greater the diffusion rate will be. The larger the particle size, the larger the diffusion rate. The diffusivity of sandy loam is 10-30 times larger than that of loam and clay loam. The relationship between water content and diffusion rate is in accordance with the exponential function . 展开更多
关键词 Hebei PIEDMONT PLAIN Soil WATER DIFFUSIVITY BOLTZMANN parameter VOLUMETRIC WATER content
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Analysis on Long Precipitation Series in Piedmont (North-West Italy) 被引量:1
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作者 Fiorella Acquaotta Simona Fratianni 《American Journal of Climate Change》 2013年第1期14-24,共11页
This study analyses thirteen daily precipitation series of Piedmont, region of North-West Italy. The meteorological series have been chosen because they were meteorological observatories operating continuously from th... This study analyses thirteen daily precipitation series of Piedmont, region of North-West Italy. The meteorological series have been chosen because they were meteorological observatories operating continuously from the beginning of 1900 until 2011. As the first step an historical research over each station has been carried out. In this way, the potential breaks, in the series, either due to changes of locations or instruments, have been determined and the missing values have been recovered. On the precipitation daily series a quality control have been effectuated and by metadata identification it was possible to assess the homogeneity of the meteorological series. In this way we have obtained the complete and correct series on which trends have been computed. In order to better understand the consequences of climate variations on our environment and society, we have calculated the climate indices proposed by “CCL/CLIVAR Working Group on Climate Change Detection” (dry and wet days, rainy days, intensity of precipitation…) over the time. The values of precipitation have also allowed beginning the climatic analysis with the aim at defining the principle local peculiarity in Piedmont. 展开更多
关键词 PIEDMONT PRECIPITATION CLIMATE Indices TREND CLIMATE Change
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History of Paleoseismic ActivityAlong the Hohhot Segment of Daqingshan Piedmont Fault in the Late Quaternary 被引量:2
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作者 Ran Yongkang and Zhang PeizhenInstitute of Geology, China Seismological Bureau, Beijing 100029, ChinaHu Bo and Guo WenshengSeismological Bureau of Nei Mongol Autonomous Region,Hohhot 010000, China 《Earthquake Research in China》 2001年第2期190-204,共15页
A detailed study on geomorphic surfaces and a set of trenches on the Hohhot segment of Daqingshan piedmont fault at three sites, Kuisu, Ulan Blang, and Qingshan Grassland, revealed 7 paleoseismic events occurred along... A detailed study on geomorphic surfaces and a set of trenches on the Hohhot segment of Daqingshan piedmont fault at three sites, Kuisu, Ulan Blang, and Qingshan Grassland, revealed 7 paleoseismic events occurred along the fault segment since 19 ka BP. Those events occurred at 18.75±.75 ka, 16.97 ±.96 ka, 14.65±.67 ka, 11.82±.69 ka, 9.45±.26 ka, 6. 83±.26 ka, and 4. 50 ±0. 23 ka BP, respectively, and their average recurrence interval is 2375±432 years. From the results of constraining fault displacement and correlation between the sediments in these trenches, we found a complete paleoseismic activity history along the fault segment during this period of time. 展开更多
关键词 Daqingshan piedmont fault Hohhot segment TRENCH Paleoseismic activity history COMPLETENESS
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皮尔蒙特牛与本地黄牛的杂交试验 被引量:3
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作者 罗海青 祁焕贵 《中国牛业科学》 2010年第1期21-22,共2页
[目的]为了掌握皮尔蒙特牛与本地黄牛杂交一代的生长发育情况。[方法]采用称重和测量体尺方法进行比较分析。[结果]表明:在同等饲喂条件下皮黄F1代杂种牛在初生重、3月龄、6月龄、12月龄重和体尺指标均明显优于本地黄牛(P<0.01)。[结... [目的]为了掌握皮尔蒙特牛与本地黄牛杂交一代的生长发育情况。[方法]采用称重和测量体尺方法进行比较分析。[结果]表明:在同等饲喂条件下皮黄F1代杂种牛在初生重、3月龄、6月龄、12月龄重和体尺指标均明显优于本地黄牛(P<0.01)。[结论]说明利用皮尔蒙特冻精杂交改良本地黄牛效果明显,是切实可行的。 展开更多
关键词 皮尔蒙特 本地黄牛 杂交
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牛胚胎移植试验报告 被引量:8
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作者 杨廷忠 刘得元 +1 位作者 仲青花 张迎春 《黄牛杂志》 2004年第5期10-11,共2页
2000年9月至2003年9月,在大通县青林、多林、逊让、向化等9个乡镇开展了安格斯牛、荷斯坦、皮埃蒙特牛冷冻胚胎移植工作。经过对298头当地黄牛母牛及杂交母牛进行了诱导同期发情,结果获得93.29%的同期发情率和38.13%的黄体合格率。对于... 2000年9月至2003年9月,在大通县青林、多林、逊让、向化等9个乡镇开展了安格斯牛、荷斯坦、皮埃蒙特牛冷冻胚胎移植工作。经过对298头当地黄牛母牛及杂交母牛进行了诱导同期发情,结果获得93.29%的同期发情率和38.13%的黄体合格率。对于黄体合格的106头母牛进行了安格斯、荷斯坦、皮埃蒙特牛冷冻胚胎移植,获得移植妊娠率42.5%。 展开更多
关键词 胚胎移植 同期发情 安格斯牛 荷斯坦牛 皮埃蒙特牛
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皮埃蒙特、利木赞牛三元杂交组合幼牛产肉性能研究 被引量:4
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作者 李军祖 《黄牛杂志》 2003年第1期25-29,共5页
本文对皮埃蒙特公牛×西黄杂种母牛 (西门塔尔公牛×当地黄牛 ,下简称皮西黄 )、利木赞公牛×西黄杂种母牛 (下简称利西黄 )两组合的三元杂交种幼牛肉用性能进行了研究。结果表明 ,两个组合肉性良好。 9月龄体重分别达 2 88... 本文对皮埃蒙特公牛×西黄杂种母牛 (西门塔尔公牛×当地黄牛 ,下简称皮西黄 )、利木赞公牛×西黄杂种母牛 (下简称利西黄 )两组合的三元杂交种幼牛肉用性能进行了研究。结果表明 ,两个组合肉性良好。 9月龄体重分别达 2 88.4kg和 2 5 9kg;育肥期平均日增重达 879.4g和 846.1 g。皮西黄屠宰率、净肉率、胴体产肉率和熟肉率分别为 5 8.2 5 %、47.5 0 %、81 .94%和 65 .4% ,利西黄分别为 5 5 .33%、45 .67%、82 .0 9%和 67%。皮西黄肉骨比、肉脂比、胴体优质切块比例和眼肌面积分别为4.5 5、1 0 .86、35 .1 2 %和 73.70 cm2 ;利西黄分别为 4.61、1 0 .2 3、33.38%和 63.1 0 cm2 。皮西黄产肉性能强于利西黄。 展开更多
关键词 皮埃蒙特牛 利木赞牛 西门塔尔牛 黄牛 三元杂交幼牛 产肉性能
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皮埃蒙特牛改良青海大通黄牛效果试验 被引量:2
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作者 陈学文 《黄牛杂志》 2005年第6期13-15,共3页
随机选择皮埃蒙特牛与大通本地黄牛的杂交F_1代(皮×黄)、皮埃蒙特牛与西门塔尔×本地黄牛三元杂交一代F_1(皮×西黄)、皮埃蒙特牛与中国荷斯坦×本地黄牛杂交一代F_1(皮×黑黄)以及纯种当地黄牛(对照)各30头公犊... 随机选择皮埃蒙特牛与大通本地黄牛的杂交F_1代(皮×黄)、皮埃蒙特牛与西门塔尔×本地黄牛三元杂交一代F_1(皮×西黄)、皮埃蒙特牛与中国荷斯坦×本地黄牛杂交一代F_1(皮×黑黄)以及纯种当地黄牛(对照)各30头公犊牛,进行饲养和育肥试验,研究皮杂牛在当地的生长及肉用性能。试验结果,6月龄时试验组牛皮×黄、皮×西黄以及皮×黑黄的体重分别为89.00、92.92、117.21kg,比对照组本地黄牛体重70.87kg分别提高了25.58%、31.11%和69.39%,差异均极显著(P<0.01)。6月龄时试验组的体高、胸围比对照组的对应测定值分别提高21.63%、22.34%、29.75%和20.32%、24.56%、31.11%,差异均极显著(P<0.01)。经育肥,18月龄杂种牛比黄牛多产肉46.01kg(每千克以14元计),每头新增产值644.14元,经济效益显著。结果表明,用皮埃蒙特牛改良当地黄牛,其后代的生长发育和肉用性能均显著高于当地黄牛。 展开更多
关键词 皮埃蒙特牛 三元杂交 生长发育 肉用性能 日增重
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Paleoseismic activity on Wujiahe segment of Serteng piedmont fault, Inner Mongolia
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作者 杨晓平 冉勇康 +1 位作者 胡博 郭文生 《Acta Seismologica Sinica(English Edition)》 CSCD 2003年第1期67-78,共12页
Geomorphic study on Wujiahe segment of Serteng piedmont fault, Inner Mongolia is made. Through analysis of the available data in combination with the results of predecessors studies it can be obtained that average ver... Geomorphic study on Wujiahe segment of Serteng piedmont fault, Inner Mongolia is made. Through analysis of the available data in combination with the results of predecessors studies it can be obtained that average vertical displacement rate is 0.48~0.75 mm/a along the Wujiahe segment since the late Pleistocene (14.450~22.340 ka BP) and 0.56~0.88 mm/a since the early-middle Holocene (5.570~8.830 ka BP). Analyzing paleoseismic phenomena revealed in the excavated 5 trenches in combination with the results of predecessors studies of paleoearthquakes on the fault, we determine five paleoseismic events on the Wujiahe segment of Serteng piedmont fault since 27.0 ka BP and the recurrence interval to be about 4.300~4.400 ka. A cluster of paleoearthquakes occurred probably during 8.000~9.000 ka BP and two paleoseismic events in 10.000~20.000 ka BP may be missed. A comparison between height of fault scarps and sum of displacement caused by paleoseismic events revealed in trenches, and recurrence interval of paleoseismic events obtained from average displacement rate along the fault and the disloca-tion by one event suggest that three paleoseismic events are absent in Alagaitu trench. Two paleoseismic events may be absent on the whole active fault segment. 展开更多
关键词 Serteng piedmont fault fault movement PALEOEARTHQUAKE recurrence interval
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Vegetation recovery after fire in mountain grasslands of Argentina
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作者 Alejandro LOYDI Flavia AFUNK Andrés GARCíA 《Journal of Mountain Science》 SCIE CSCD 2020年第2期373-383,共11页
Fire is a natural disturbance occurring every few years in many grasslands ecosystems. However, since European colonization, fire has been highly reduced or even suppressed in Argentinean grasslands, fostering ignitab... Fire is a natural disturbance occurring every few years in many grasslands ecosystems. However, since European colonization, fire has been highly reduced or even suppressed in Argentinean grasslands, fostering ignitable material accumulation. This has led to occasional catastrophic controldemanding fire events, extended for larger areas. The aims of this work are to study vegetation recovery and change after a non-natural fire event in mountain grasslands. The study area is located in the Ventania mountain system, mid-eastern Argentina. We studied vegetation recovery after fire(January 2014) in two different communities: grass-steppes(grasslands) and shrub-steppes(open low shrublands). We measured vegetation cover, species richness and bare ground percentage in burned and unburned areas 1, 4, 8, 11 and 23 months after fire. Vegetation surveys were also performed at the end of the growing season(December) 11 and 23 months after fire. Data were analyzed using regression analysis, ANOVA and multivariate analysis(NMS, PERMANOVA). Both communities increased their vegetation cover at the same rate, without differences between burned and unburned areas after two years. Species richness was higher in shrublands and their recovery was alsofaster than in grasslands. Considering functional composition, besides transient changes during the first year after fire, there were no differences in abundance of different functional vegetation groups two years after fire. At the same time, shrublands showed no differences in species composition, while grasslands had a different species composition in burned and unburned plots. Also, burned grassland showed a higher species richness than unburned grassland. Data shown mountain vegetation in Pampas grassland is adapted to fire, recovering cover and richness rapidly after fire and thus reducing soil erosion risks. Vegetation in mountain Pampas seems to be well adapted to fire, but in grasslands species composition has changed due to fire. Nonetheless, these changes seem to be not permanent since prefire species are still present in the area. 展开更多
关键词 Amelichloa caudata FORBS Grass Natural grassland Nassella trichotoma Piedmont valleys SHRUBS Sierra de la Ventana Vegetation functional groups
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Parameters of the AD 849 earthquake east of Baotou City in Inner Mongolia and the adjustion of the potential seismic sources zone spatial distribution functions
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作者 Ji Wang Zhanwu Gao +3 位作者 Wei Xu Zhaode Yuan Zhicheng Liu Xiaoliang Zhang 《Earthquake Science》 2019年第3期170-178,共9页
According to volume 18(Xuanzong Ji Tang)of the historical book entitled the Old Book of Tang,the Hetao area of Inner Mongolia experienced a large earthquake in AD 849.However,previous work on that earthquake contains ... According to volume 18(Xuanzong Ji Tang)of the historical book entitled the Old Book of Tang,the Hetao area of Inner Mongolia experienced a large earthquake in AD 849.However,previous work on that earthquake contains many discrepancies regarding its epicenter location,magnitude,deaths,and intensity.While exploring active faults in Baotou City,the present authors mapped the Daqing Mountain piedmont fault geologically.Based on previous work,several seismic deformation traces of more than 1000 years ago were found,and dating tests were conducted.The research showed the Daqing Mountain piedmont fault zone to be the seismogenic structure of the AD 849 earthquake.The length of earthquake surface rupture zone was around 80 km,and the macro epicenter was located in the active fault.The deformation center was located at 40.6°N,110.2°E.By collecting and analyzing more historical data about the AD 849 earthquake,reinterpreting some existing historical data,and re-examining the contradictory numbers of deaths in the historical data,the present analysis concludes that around 10,000 people were dead.It is suggested that this earthquake had a magnitude of 7½.According to the revised seismic parameters and the paleoearthquake recurrence period of the Daqing Mountain piedmont fault,the boundary of some potential seismic sources zone in the Baotou area are adjusted and the recurrence period of M8 and M7.5 are re-calculated. 展开更多
关键词 EARTHQUAKE rupture traces parameters AD 849 Daqing Mountain piedmont fault
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