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论湘中城市群经济的融合耦动与可持续发展 总被引:3,自引:0,他引:3
本文以湘中(长株潭)城市群作为研究对象,概述了湘中城市群经济融合的总体特征,对其城市群空间生长演化过程中存在的问题和应采取的对策,经济如何实现可持续发展进行了探讨。 相似文献
393.
武汉地区防汛抗洪中存在的几个主要问题与对策 总被引:1,自引:1,他引:0
简述了1998年武汉市防汛抗洪中存在的几个主要问题,并提出了相应的对策与建议. 相似文献
394.
The role of condensed organic matter in the nonlinear sorption of hydrophobic organic contaminants by a peat and sediments 总被引:2,自引:0,他引:2
This study examines the effect of soil organic matter heterogeneity on equilibrium sorption and desorption of phenanthrene, naphthalene, 1,3,5-trichlorobenzene (1,3,5-TCB), and 1,2-dichlorobenzene (1,2-DCB) by soils and sediments. Two estuary sediments, a Pahokee peat (PP; Euic, hyperthermic Lithic Haplosaprist), and two subsamples (base- and acid-treated peat [TP] and acid-treated peat [FP]) of the peat were used as the sorbents. The contents of black carbon particles were quantified with a chemical extraction method. Petrographical examinations revealed the presence of the condensed soil and sediment organic matter (SOM) in Pahokee peat. The Freundlich isotherm model in two different forms was used to fit both sorption and desorption data. The results show that the sorption and desorption isotherms are generally nonlinear and that the apparent sorption-desorption hysteresis is present for phenanthrene and TCB. Detailed analysis of sorption data for the tested sorbent-sorbate systems indicates that black carbon is probably responsible for sorption isotherm nonlinearity for the two sediments, whereas the humic substances and kerogen may play the dominant role in nonlinear sorption by the peat. This investigation suggests that the microporosity of SOM is important for the hydrophobic organic contaminant (HOC) sorption capacity on the peat. 相似文献
395.
ABSTRACT. Planning an optimal system of activities for generating economic goods and services within an existing natural resource capacity is a difficult problem to solve. A mathematical programming model with the capacity to check multiple resource demand and supply compatibility over many time periods was developed for the solution to this type of problem. The characteristics of natural resource supply and the demand of activities were utilized to reduce the number of time periods and to minimize the loss of the dynamic reality of the problem. Reduction in the number of time periods extended the capability of the model to the solution of complex resource planning problems without oversimplification. 相似文献
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Chiang Hung-Lung Huang Yao-Sheng 《Atmospheric environment (Oxford, England : 1994)》2009,43(26):4014-4022
Particulate matter, including coarse particles (PM2.5–10, aerodynamic diameter of particle between 2.5 and 10 μm) and fine particles (PM2.5, aerodynamic diameter of particle lower than 2.5 μm) and their compositions, including elemental carbon, organic carbon, and 11 water-soluble ionic species, and elements, were measured in a tunnel study. A comparison of the six-hour average of light-duty vehicle (LDV) flow of the two sampling periods showed that the peak hours over the weekend were higher than those on weekdays. However, the flow of heavy-duty vehicles (HDVs) on the weekdays was significant higher than that during the weekend in this study. EC and OC content were 49% for PM2.5–10 and 47% for PM2.5 in the tunnel center. EC content was higher than OC content in PM2.5–10, but EC was about 2.3 times OC for PM2.5. Sulfate, nitrate, ammonium were the main species for PM2.5–10 and PM2.5. The element contents of Na, Al, Ca, Fe and K were over 0.8 μg m?3 in PM2.5–10 and PM2.5. In addition, the concentrations of S, Ba, Pb, and Zn were higher than 0.1 μg m?3 for PM2.5–10 and PM2.5. The emission factors of PM2.5–10 and PM2.5 were 18 ± 6.5 and 39 ± 11 mg km?1-vehicle, respectively. The emission factors of EC/OC were 3.6/2.7 mg km?1-vehicle for PM2.5–10 and 15/4.7 mg km?1-vehicle for PM2.5 Furthermore, the emission factors of water-soluble ions were 0.028(Mg2+)–0.81(SO42?) and 0.027(NO2?)–0.97(SO42?) mg km?1-vehicle for PM2.5–10 and PM2.5, respectively. Elemental emission factors were 0.003(V)–1.6(Fe) and 0.001(Cd)–1.05(Na) mg km?1-vehicle for PM2.5–10 and PM2.5, respectively. 相似文献
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本文选取泾阳地磁台2007年FHD-1核旋磁力仪和CB3磁变仪观测数据采用日变幅形态、日均值年变形态、总场21点值年变形态等方法做对比分析。结果表明:两种观测一致性较好,说明数字化仪器观测的数据是可靠的,但是数字化仪器还存在易受外界环境干扰,稳定性不好的问题,需要工作人员按规范调试仪器,认真维护与管理。 相似文献