996 resultados para 227


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介绍了复合人工湿地塘床系统在辽河油田特稠油采出水处理中的设计和应用情况 ,经该系统处理后 ,特稠油采出水可以实现达标排放

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Venezuela is located in central northern South America, with some 4 000 km of coastline and near 700 000 km2 of marine and submarine areas. The Venezuelan coastal zone is characterized by serious problems of land use and utilisation of its natural resources, caused by a generally anarchical spatial occupation and lack of sufficient legal and administrative means for control. In this paper, a synthesis of the Venezuelan approach to attaining a sustainable development of its marine and coastal zones is presented. This means the accomplishment of the social and economic development of the Venezuelan population in general, and specifically the coastal inhabitants, taking into account the legal and administrative patterns that govern land use planning and the utilisation of natural resources, particularly in marine and coastal areas. The paper is organised in three parts: (1) the diagnosis of the current situation; (2) the presentation of a hypothesis based on present trends (trend scenario); and (3) the statement and application of a sound and adequate solution (desirable and possible scenario).

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采用以空间代替时间的方法,对连栽杉木(Cunninghamialancelata(Lamb)Hook)人工林中采伐剩余树桩的分解过程进行了研究.根据Olson的分解模型,计算出连栽杉木纯林中树桩的分解速率为0.02695,树桩在分解过程中的前2年是一个氮素增加积累过程,当杉木树桩的C/N在463.2±27.3时开始净氮释放.树桩磷含量的变化与氮变化模式相类似,但钾的表现不同,钾的含量在树桩分解过程中一直是单调降低.利用固体高分辨核磁共振技术结合魔角旋转(MAS)和交叉极化(CP)技术,研究了杉木树桩的腐殖化过程及碳结构的变化.树桩中由纤维素和半纤维素组成的多糖碳和乙缩醛被首先分解,而由蜡质和表皮素等化合物组成的烷基碳,由酚类、木质素、单宁和石蜡等化合物组成的芳香族碳,及由酯、有机酸、酮和醛等化合物组成的羧基碳的分解速度较多糖碳和乙缩醛慢.

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结合样地调查和他人对阔叶红松林生态系统相关指标的研究资料数据,利用健康距离(HD)评估法和上文建立的阔叶红松林生态系统健康评估指标体系框架,对不同人为干扰影响的长白山阔叶红松林生态系统进行系统健康的评估实践.结果按顺序依次为20%强度择伐林021<50%强度择伐林044<白桦中成林067<白桦中幼林072<红松人工林074<人工落叶松林077.

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在探讨PDF文件格式的基础上,提出了一种通用三维(简称U3D)文件格式嵌入到PDF文件中的方法。这种方法具有可扩展性,对于如何在其他文件中支持U3D文件格式的应用研究也具有一定的参考价值。最后,还通过C++编程实现了在PDF文件中嵌入3D作品,并允许用户交互地观看显示效果。

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The binding-site number was calculated by using fluorescence spectroscopic method with bovine serum albumin(BSA) and Indo-1 as protein and ligand models, respectively. The method for calculating binding-site number in BSA for Indo-1 was developed based on the relationships between the changes of Indo-1 fluorescence intensity and the analytical concentration of BSA. And the interaction of BSA with Indo-1 was investigated comprehensively by using fluorescence techniques as well as fluorescence resonance energy transfer, and the thermodynamic parameters were calculated according to the changes of enthalpy on temperature.,

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Cinnabar, an important traditional Chinese mineral medicine, has been widely used as a Chinese patent medicine ingredient for sedative therapy. However, the pharmaceutical and toxicological effects of cinnabar, especially in the whole organism, were subjected to few investigations. In this study, an NMR-based metabolomics approach has been applied to investigate the toxicological effects of cinnabar after intragastrical administration (dosed at 0.5, 2 and 5 g/kg body weight) on male Wistar rats.

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采用熔融共混的方法制备了聚碳酸1,2-丙二酯(PPC)/聚琥珀酸丁二酯(PBS)共混物和PPC/PBS/DAOP(邻苯二甲酸二烯丙酯)增塑共混物,对共混物的相容性、热性能、结晶性和物理机械性能进行了初步研究.研究结果表明PPC/PBS共混物为不相容体系,PPC对PBS的结晶度影响很小;PBS的加入提高了共混物的起始热分解温度(Td-5%),当共混物中PBS含量从10%增加到90%时,共混物的Td-5%可分别增加15℃到59℃.DAOP对PPC/PBS共混物有增塑作用,当PPC/PBS/DAOP的比例从30/70/0变化到30/70/30时,共混物玻璃化转变温度(Tg)下降了36.9℃.与PPC/PBS共混物相比,组成优化的DAOP增塑共混物PPC/PBS/DAOP(PPC/PBS/DAOP=30/70/5)的断裂伸长率和断裂能最大可提高31倍和34倍,分别达到655.1%和3.4 J/...

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以牛血清白蛋白(Bovine serum album in,BSA)与荧光探针Indo-1为蛋白质和配体模型,基于Indo-1的荧光强度与BSA的分析浓度间的关系,建立了计算二者相互作用位点数的方法,并利用荧光共振能量转移及各种荧光技术对Indo-1和BSA的相互作用进行了研究.结果表明,Indo-1在BSA中有3个作用位点,这3个作用位点与BSA中的212位色氨酸(Trp 212)间的距离分别为2.93,2.57和2.40 nm;Indo-1通过疏水性作用进入到BSA的3个疏水性空腔.在荧光猝灭实验中,通过M icrolab 500系列进样器和PTI荧光仪的联用实现了荧光强度的自动和实时记录.

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In this paper, the interaction mechanism between La3+ and microperoxidase-11 (MP-11) in the imitated physiological solution was investigated with the electrochemical and spectroscopic methods. It was found that when the molar ratio of La3+, and MP-11 is low, such as 2, La3+ can coordinate with oxygen in the propionic acid group of the heme group in the MP-11 molecule, forming the La-MP-11 complexes and leading to the increase in the non-planarity of the porphyrin cycle in the heme group and then the increase in the extent of exposure of the electrochemically active center, Fe(I I I) in the porphyrin cycle of the heme group. The increase in the extent of exposure of the electrochemically active center, Fe(III) in the porphyrin cycle of the heme group would increase the reversibility of the electrochemical reaction of the La-MP-11 complexes and its electrocatalytic activity for the reduction of H2O2. The results of the chromatographic analysis demonstrated that the average molar ratio of La3+ and MP-11 in the La-MP-11 complexes is 1.62.When the molar ratio of La3+ and MP-11 is high, such as 3, La3+ would shear some amino acid residues of the peptide of MP-11. Therefore, many La3+ ions can bind to the oxygen- and/or nitrogen-containing groups in the sheared amino acid residues except coordinating with the sheared and non-sheared MP-11 molecules.