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主要阐述了沥青作为黑色路面的主要胶结材料,在具体应用中对其质量控制指标的认识和重视.以及各项控制指标代表的沥青材料物理、化学、力学等方便特性,体现了这些指标在路面工程中的重要性. 相似文献
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我国公路建设进入维修养护时期,大量的废旧沥青混合料亟待加以利用,同时半刚性基层路面易产生脆性断裂,影响路面的使用性能。本文将废旧沥青混合料再生掺加到半刚性基层材料中,从不同角度分析废旧沥青混合料对半刚性基层材料性能的影响。结果表明:随着混合料掺量的增大,材料的抗压强度呈现出先增长后减小的变化规律。当废旧沥青混合料的掺量在15%~20%之间时,水泥稳定基层材料的抗压强度达到最大值。因此,工程中完全可以用废旧沥青混合料取代一定比例的新集料,但在不增加水泥剂量的前提下,废旧沥青混合料掺量不宜超过集料总质量的20%。 相似文献
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沥青路面冷补材料试验研究 总被引：1，自引：1，他引：1
针对目前沥青混凝土路面养护修补主要使用的热拌热铺沥青混合料受气候影响的问题，进行冻土地区沥青路面冷补材料的试验研究。通过对冷补沥青混合料在不同试验条件下进行非标准马歇尔稳定度试验结果分析，从而寻找出影响马歇尔试验值的因素和适合于评定沥青冷补材料的室内试验方法及评价指标。 相似文献
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对浇注式沥青混凝土高温稳定性较差的原因进行了分析,在此基础上对其进行改进设计,提出高温稳定性较好的浇注式沥青混凝土材料设计方案。对于将浇注式沥青混凝土应用于我国钢桥面铺装具有一定的指导价值。 相似文献
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为设计出符合南京地区降雨特征的透水性沥青混合料,对开级配沥青混合料配合比设计方法进行了改进。按照南京地区降雨特征采用体积法进行透水性沥青混合料配合比设计,同时通过室内试验对透水性沥青混合料的路用性能进行了验证。试验结果表明:设计的透水性沥青混合料(最佳沥青用量6.0%、空隙率22.4%)混合料,其承载能力、高温抗变形能力、低温性能、水稳定性等方面性能良好,符合路用性能要求。因此在南京市使用该透水性沥青混合料作为透水性沥青路面面层材料可以有效避免由于雨水来不及下渗而出现地表径流的现象。 相似文献
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调查了松幽天牛(Asemum amurense)在余姚地区的发生情况及其幼虫在枯死松树根内的分布规律。结果表明,松幽天牛在余姚地区1年发生1代,以幼虫在松树根内越冬。4月中旬开始化蛹,5月中旬成虫开始羽化,6月上旬成虫开始产卵,7月下旬卵开始孵化。松幽天牛在余姚地区的平均危害率达42.9%,其发生与土壤理化性质密切相关。松幽天牛幼虫在主、侧根内的分布数量差异显著,主根内的幼虫数显著多于侧根内。还依据松幽天牛的生活学特性提出了松幽天牛的防治措施 相似文献
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《Journal of Sustainable Forestry》2013,32(2-3):115-127
Abstract Seasonal behavior of vascular cambium and development of secondary xylem were studied in the 2-3-years-old branches of Azadirachta indica A. Juss. (Meliaceae) growing in moist deciduous (MDF), dry deciduous (DDF) and scrub land (SF) forests of Gujarat State. Development of xylem began with the sprouting of new leaves in January in both MDF and DDF. Xylem production culminated in July in MDF whereas it reached peak in April and July in DDF. Cambial cells ceased to divide with the maturation of leaves in November and October in MDF and DDF, respectively. Mature xylem and phloem derivatives surrounded the cambium in December in MDF and November in DDF. Radial growth in the branches of trees growing in SF was found continuous throughout the year with peak cambial activity in April, July and November. In all the three forests, maximal radial growth was encountered in July when the rains were heavy. Cambial activity and xylem development showed significant correlation with the phenology of the trees in MDF and DDF whereas cambium was found active throughout the year and no correlation was found between the cambial activity and phenology in SF. 相似文献
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Deciduous trees with high-density wood that occur in dry seasonal tropical regions respond to rainfall seasonality with synchrony in phenophases. However, they may exhibit interannual differences in sy... 相似文献
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【目的】研究不同生境和收获时间对圆齿野鸦椿不同部位总三萜类化合物积累的影响情况,为其药用价值和科学栽培的研究奠定基础。【方法】选择3个低海拔地区的8年生圆齿野鸦椿,分别于2014年11月和2015年3月采集其叶片、枝条和果实,选择高海拔地区6年生的野鸦椿和圆齿野鸦椿,于2014年8月分别采其叶片和枝条,对其总三萜类化合物含量进行了测定和比较分析。【结果】1)8月采集的叶片中三萜类化合物的含量,野鸦椿高于圆齿野鸦椿,且其含量差异呈显著性水平;但是,8月采集的枝条中三萜类化合物含量,野鸦椿低于圆齿野鸦椿。2)圆齿野鸦椿不同部位的总三萜类化合物含量存在差异,且2个月份采集的含量高低顺序均为叶片>枝条>果皮>种子,均以叶片中的含量为最高,依次为9.06%(农大)、7.14%(清流)和6.85%(邵武)。3)11月采集的圆齿野鸦椿样品中的三萜类化合物含量高于3月所采样品中的含量,其叶片中的总三萜类化合物含量最多可提高172.91%。4)圆齿野鸦椿叶片、果皮和种子中的三萜类化合物含量与试验地的海拔高度、年降水量均表现出极显著的负相关关系,与年均气温存在极显著的正相关关系,其叶片中的三萜类化合物含量还与年均无霜期呈正相关关系,其枝条中的三萜类化合物含量与各地理和气象因素之间的相关性均不显著。【结论】圆齿野鸦椿的叶片采收期长于野鸦椿;低海拔、较少降水量和年均气温较高有利于圆齿野鸦椿植株对三萜类化合物的累积,这3个因子可以作为圆齿野鸦椿适宜栽培区域的划分指标;夏季采摘野鸦椿叶片,秋冬季采摘圆齿野鸦椿叶片,所采叶片的总三萜类化合物的含量均较高。 相似文献
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Yuan Li Li Xiaomin Yu Hongxian Guo Libin Zhang Taizhong Gao Qingjun Zeng Daihua 《林业研究》1997,8(4):235-239
There are five species of swan in the world. Three of them were recorded in China. They are whooper swan (Cygnus cygnus), whistling swan (Cygnus columbianus) and mute swan (Cygnus olor). Among them. whooper swan is the most famous in China. Whooper swan is a resident bird in China. They breed in Xinjiang
Ugyur Autonomous Region. Inner Mongol Autonomous Region. Heilongjiang Province. etc., and winter in Qinghai. Shandong. Henan
Province, etc, and the lower reaches of the Changjiang River. The total number in China is about 5.000 in breeding grounds
and 15.000 in wintering grounds. Higher number were found in 1960s. Because of the changes in environment and hunting, of
picking up eggs and of catching nestlings, their population is being reduced rapidly. They are in danger now. In order to
protect the whooper swans, some protection measures must be taken, such as strengthening public education and scientific research,
estabilshing a base of raising and breeding: developing international cooperation, strengthening the construction of natural
reserves in the breeding and wintering grounds. Up to the end of 1993. 34 natural reserves have been established in China.
(Responsible Editor: Sun Yueqi) 相似文献
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研究了百山祖冷杉(Abies beshanzuensis)分布区适生立地表层土壤养分及其与百山祖冷杉枝叶营养元素含量的相关性.结果表明,土壤pH5.11～6.42,土壤有机质含量、全氮含量、速效磷含量、速效钾含量分别为119.075 0g/kg、2.196 2g/kg、15.016 3mg/kg、136.215 2mg/kg;百山祖冷杉对土壤N、P、K富集能力均较高,而对微量元素富集能力较弱,且枝部和针叶均未检出Na元素;较高的土壤N含量,可相应显著提高百山祖冷杉叶N、K含量水平,较高的土壤P含量,则显著抑制百山祖冷杉叶对K和枝对N的积累水平,较高的土壤Cu含量显著降低了Cu元素在叶器官中的积累,而显著增加了枝条中Cu和Zn的积累水平,较高的土壤Fe含量则显著促进了针叶中Fe元素和枝中Fe、Mn元素的积累水平. 相似文献
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为了探讨枸杞果柄分离力与果实、果柄形态及内源激素间的关系,从而为枸杞鲜果新品种选育及其鲜果产业发展提供理论依据,分别以蒙杞2号和宁杞7号为试材,采用酶联免疫法测定了果实与果柄中ABA、IAA、GA_3、ZR的含量,分析了枸杞果实发育期内果实与果柄的形态及内源激素和果柄分离力间的关系。结果表明:果柄分离力随着果实的发育成熟而不断降低,其与单果质量、果实纵径、果实横径间均有显著的负相关性,其相关系数分别为-0.771、-0.862、-0.883;果柄分离力与果实中各内源激素的相关系数均较高,而与果柄中各内源激素的相关系数均较低。果实中的ABA含量在果实膨大初期开始上升,至果实成熟期,蒙杞2号果实中的ABA含量下降,而宁杞7号果实中的ABA含量仍较高;果实中的IAA含量逐渐下降,并显著低于果柄中的IAA含量,蒙杞2号果实中的IAA含量低于宁杞7号果实中的IAA含量;果实中GA_3与ZR的含量均逐渐下降,且宁杞7号果实中GA_3与ZR的含量均高于蒙杞2号的;果柄中GA_3与ZR的含量变化均不明显;ABA、GA_3、ZR在宁杞7号果实与果柄中的含量比均高于其在蒙杞2号果实与果柄中的含量比,宁杞7号果实中ABA/(IAA+GA_3+ZR)之值也高于蒙杞2号果实中ABA/(IAA+GA_3+ZR)之值。文中综合分析认为,ABA、GA_3、ZR在枸杞果实与果柄中的含量比和果实中ABA/(IAA+GA_3+ZR)之值均高可能是导致果柄分离力小的主要原因。 相似文献
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Yabing Zhang Chuanyan Zhou Wenqiang Lv Lihua Dai Jingang Tang Shaoqi Zhou Lihua Huang Anding Li Jianli Zhang 《林业研究》2019,(3):799-806
Carbon (C), nitrogen (N), and phosphorous (P) levels and their stoichiometry in plant components (leaves, branch trunks, roots) of trees in a karst forest and non-karst forest are compared. The results show that the C contents, C:N and C:P ratios of dominant species in the karst forest were lower than those in the non-karst forest, but the N and P and the N:P ratio were higher;C:N:P ratios in plant organs of trees in the karst forest were in the order of trunks>roots>branches>leaves. However, C:N:P ratio in the non-karst forest trees were trunks>branches>roots>leaves. Moreover, ratio of C:N:P in trunks was highest and lowest in leaves in both forests. In non-karst forest trees, N:P was in the order of leaves> roots>branches>trunks. There were no significant differences in the ratio of N:P in different plant components of trees in the karst forest. However, in karst and non-karst forest trees, the ratio of N:P in leaves was highest;positive correlations between N and P contents, and N and N:P ratios were observed in both karst and non-karst forests (p<0.001). Negative correlations between P and N:P ratios (p<0.05) were observed in karst forest trees, while positive correlations were observed in non-karst forest trees. 相似文献
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42种树叶氨基酸组成的研究 总被引：2，自引：0，他引：2
本文研究了中国42种针、阔叶树种树叶中18种蛋白质氨基酸的含量和组成在不同科、属、种之间和不同立地条件下,不同的生长季节进行了比较和探讨。为了进一步研究它们的利用价值,着重研究了与部分粮食和肉类中蛋白质氨基酸组成之间的差别。阔叶树树叶中总的蛋白质氨基酸含量约为针叶树树叶2—3倍。所有树种的树叶蛋白质氨基酸的组成趋势基本相似,树叶中含量较高的氨基酸有天门冬氨基酸、谷氨酸等8种。树叶中总的氨基酸含量高于粮食2—3倍,而且树叶中蛋白质氨基酸的组成趋势与粮食和肉类不完全相同,特别是人和动物体内不能自身合成的8种必须氨基酸的含量分别为高粱、玉米的3倍,麦麸的2倍,与肉类相比,树叶中亮氨酸和苯西氨酸,占蛋白质氨基酸总量百分比高出4—5倍。结果表明,阔叶树叶是优良的饲料添加剂。 相似文献