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91.
92.
碳酸盐岩酸不溶物作为贵州岩溶区红色风化壳主要物质来源的证据 总被引：26，自引：4，他引：26
贵州岩溶区红色风化壳是中国南方红色负化壳的重要组成部分，本文根据部分红色风化壳剖面野外特征、矿物学、地球化学及土壤物理学等的研究结果，对其物源及成因进行了探讨。各剖面，尤其邻近剖面显著的矿物学、地球化学差异排除了远程风成沉积物、火山灰、上覆或者高处碎屑岩层作为统一且重要物源的可能。极低的石英含量表明贵州常见的长石石英砂岩不是其主要物源，具有中稀土（MREE）富集的特征也排除了粘土岩、页岩作为主要物源的可能。风化壳剖面间的差异性均可从基岩酸不溶物的差异性得到很好解释，表明它们是下伏碳酸盐岩风化、酸不溶物（准）原地堆积的结果。部分剖面甚至显示了典型风化壳剖面的一些特征，具有正常风化序列的剖面结构特征。 相似文献
93.
在黄土高原选择了１２个现代黄土堆积的典型地点,采集表层及５ｃｍ深度处的黄土样品,提取植物残体作稳定同位素分析。发现：（１）不同深度样品的植物残体δ１３Ｃ值差异明显,可形成高分辨率的时间序列;（２）植物残体的δ１３Ｃ值与气温的对应关系具有分区的特征,子午岭以西的黄土地区为负相关,其余地区比较复杂;（３）植物残体的δ１３Ｃ值与降水的关系不密切。 相似文献
94.
95.
Maria Lúcia Calijuri Eder T. Marques Juliana F. Lorentz Roberto F. Azevedo Carlos A. B. Carvalho 《Geotechnical and Geological Engineering》2004,22(2):299-312
The municipality of Cachoeiro de Itapemirim (ES) is currently the largest domestic producer and exporter of marble and granite
in Brazil. The processing of the rock, especially the sawing results in a large volume of waste, including the abrasives used
during sawing and the off-cut pieces. Presently these waste products are disposed of without proper environmental protection
and cause pollution to surface water and groundwater resources, including silting, an increase in hardness and increased aluminium
values in the groundwater. In order to minimize the harmful effects of these practices on the environment, a research project
was undertaken to identify potential disposal sites for the generated waste. A multi-criteria approach was followed during
which a database was compiled of all the companies generating waste products and also including a baseline environmental study
of the region, integrated analysis (multi-criteria analysis) of the restriction factors and the preliminary identification
of possible disposal sites.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
96.
依据JJF10591—2012《测量不确定度评定与表示》,分析高效液相色谱法测定罗非鱼中孔雀石绿残留量不确定度的来源,从影响不确定度的标准溶液配制us、样品前处理up和仪器测量uu等3个主要因素,对不确定度各个分量进行计算和合成,得出罗非鱼中孔雀石绿的扩展不确定度U=088（k=2）。 相似文献
97.
This study examined the distribution and elimination of Norfloxacin(NFLX) in Fenneropenaeus chinensis ovary and egg and newly hatched larvae.Mature parental shrimp were exposed to 4 or 10 mg L 1NFLX for 2 or 5 d.Ovary and eggs of the shrimp were sampled after spawning in order to detect NFLX residue using high-performance liquid chromatography(HPLC).Results showed that NFLX residue accumulated in F.chinensis eggs after the parental exposure,with the highest residue detected in ovary.To examine the fate of NFLX residue in larvae,we further determined the concentration of NFLX residue in F.chinensis eggs and larvae at 4 different developmental stages after 24-h exposure.From the newly metamorphosed larvae(0 h post-metamorphosis,h.p.m),samples were taken at different time intervals to 72 h.p.m.HPLC assay showed that the concentrations of NFLX residue in zoea exposed to 4 and 10 mg L 1NFLX were the highest at 1.5 h,i.e.,0.332 and 0.454 μg g 1,respectively.At the two NFLX exposure levels,the elimination time of half NFLX(half life) in nauplius was 45.36 and 49.85 h,respectively,followed by that in zoea(31.68 and 33.13 h),mysis larvae(42.24 and 47.28 h) and postlarvae(24.48 and 30.96 h).Both NFLX exposure levels had a germicidal effect.The distribution and elimination of NFLX residue in F.chinensis tissue,eggs and larvae correlated well with the drug exposure level.The disappearance of NFLX residue coincided with the larval growth,and the half-life of NFLX decreased with the larval development. 相似文献
98.
99.
Population increases, land-use changes and marketing opportunities are important factors affecting crop-livestock integration
particularly with respect to their effect on soil fertility and feed supply for ruminant livestock. As the human population
density rises, crop farmers and grazers are finding it profitable to establish contracts for paddocking, and they are reaching
agreement on equitable ways to make use of crop residues and take care of livestocks. As the processes of intensification
proceed, mixed crop-livestock systems are evolving as the viable and dominant farming system, allowing smallholder farmers
to capitalize on the complementarity between crops and livestock. Strategies directed to raise the productivity of specific
crop-livestock systems need to consider the stage of development of the target area in relation to intensification and the
nature of crop-livestock interactions. Information related to crop and livestock systems in West Africa is currently available
from various sources e.g., household surveys, aerial surveys, rural appraisal, experimental etc., and held by different agencies.
The approach used in this study shows how such data (biophysical and socioeconomic) can be integrated within a GIS environment
and synthesized to identify the evolution of systems across environments and also to identify constraints and potential of
the systems. Potential for integrated crop-livestock systems remains untapped and/or knowledge of its existence is unknown
for large parts of Nigeria. Using data from 36 case studies and georeferenced data on cropping intensities and livestock population
for the entire country, it was possible to predict emerging crop-livestock systems using GIS. Indeed, depending on availability
of data, it is now possible to extend a similar approach in other African countries. The potential contribution of this technology
is largely unknown in West and Central Africa, where few operational programs use them. Major technological innovations and
appropriate government policies have potential to shift the balance in regional developments, if targeted carefully at areas
where the right conditions exist. Further research could then target specific areas thus ensuring efficient allocation of
resources while policy makers can achieve development goals by directing policies and resources to domains that have the greatest
potential.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
100.
食物的加工和利用反映了古人对动植物资源的利用,而欧亚大陆东西部地区有着不同的饮食文化习惯.新疆长期以来是东西方文化交流的枢纽,是东西方饮食文化的汇聚之地.比孜里墓地位于新疆塔里木盆地南沿洛浦县,属于古于阗国的管辖范围,是丝绸之路上的重要节点之一;该墓地出土的汉晋时期食品残留物为探讨当时饮食文化提供了难得的研究材料.本文通过红外光谱分析、植物微体化石、碳氮稳定同位素分析和蛋白质组学等多种手段对出土的一个疑似食物残留物进行综合研究.结果显示,比孜里墓地出土的疑似食物遗存应为面食,其制作工艺为混合黍面和少量大麦面粉,并添加少许肉类,烤制而成.原始形状可能为圆形,与山普拉墓地兽皮袋出土样品、新疆现代肉馕相近.在面食中添加肉食可以改善口味、提高营养,可见汉晋时期先民面食制作的讲究.同时,也为先民的动植物利用、生计方式提供了丰富信息. 相似文献