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煤层水力压裂合理参数分析与工程实践 总被引:3,自引:2,他引:1
煤层水力压裂技术是近年来应用于高瓦斯低透气性突出煤层的一种卸压增透消突技术,人们对水力压裂的卸压增透消突机理有了较充分的认识,现场工程应用的效果也较好,但有关煤层水力压裂参数是如何确定的系统分析却是很少。笔者在阐述水力压裂机理及压裂过程的基础上,系统地阐述高瓦斯低透气性突出煤层水力压裂所需的注水压力、流量、注水时间、注水速度、孔间距、封孔长度等技术参数以及煤体内在因素的影响作用;最后在义安矿FD003工作面进行了水力压裂试验研究和效果考察,得出适合义安矿的水力压裂合理注水参数。通过水力压裂,煤层瓦斯抽放量和抽放浓度得到大幅度提高,达到了卸压增透防突效果,同时起到了润湿煤体和降尘效果。 相似文献
999.
纳米材料对生物体的毒性研究 总被引:1,自引:0,他引:1
运用Einstein第一扩散公式和沉降公式,半定量、定量地说明纳米粒子沉降速度大约是微米粒子的千万分之一,更易悬浮在大气和溶液中,被生物体通过呼吸系统和循环系统所吸收;运用范德华力引起的相互作用势能公式,半定量地说明纳米粒子比微米粒子更容易吸附和团聚,通过大气中粒子转化、水体及土壤中的迁移传播等途径,由食物链富集到生物体内。可见,纳米粒子要比微米粒子的毒性更加严重,更能影响生物体的健康。同时,从纳米材料毒性影响因素对生物体的作用上看,纳米粒子也是严重影响着生物体的健康,给生物体带来极大的危害,并根据纳米材料的毒性研究结果为今后纳米技术的良性发展提出了新的方向。 相似文献
1000.
Spatial and Temporal Trends of Physicochemical Parameters in the Water of the Reconquista River (Buenos Aires, Argentina) 总被引:1,自引:0,他引:1
Castañé PM Rovedatti MG Topalián ML Salibián A 《Environmental monitoring and assessment》2006,117(1-3):135-144
The Reconquista river is one of the most polluted watercourses in Argentina. More than 3 million people and over 10,000 industries
are settled on its basin. The available data show that pollution is mainly related to the discharge of domestic and industrial
liquid wastes that are poured into the river almost untreated. At present no site of the river can be characterized as free
of pollutants. Samples were taken monthly from 5 sites of the river; some 18–20 physicochemical parameters were determined
in each sample. Analyses revealed significant differences in the degree of deterioration between sites. Two of them, close
to the source of the river (Cascallares-S1 and Paso del Rey-S2) resulted less polluted than the two points located close to the mouth of the river (San Martin-S4 and Bancalari-S5). The worsening of the water quality in S4–S5 was attributed to the discharges of the Moron stream, a tributary that flows into the main course of the river a complex
mixture of non treated waste waters. PCA was used in the ordination of samples (sites, season and physicochemical parameters).
In the PCA performed using all variables, the first principal component showed positive correlation with N-NH4
+, conductivity, orthophosphate, BOD5, COD and alkalinity, and negative correlation with DO. The second principal component was positively correlated with pH,
temperature and chlorophyll a and negatively with phenols and hardness. In respect to the spatial distribution, the plot of the scores for the first two
components of samples taken in each sampling station showed S1 and S2 values displayed farthest at the left side of the X axis with high DO. In contrast, S4 and S5 values stayed at the right side of this axis with high N-NH4
+, conductivity, orthophosphate, BOD5, COD and alkalinity; data of S3 were “intermediate". In order to identify seasonal trends in the concentration of contaminants scores of cases labeled by
season were plotted. The line drawn on the ordination plane showed that summer samples tended to converge to the upper right
portion of the graph where pollution variables had more importance on the first axis, and along the second axis with high
correlation with pH, temperature and chlorophyll a. Winter scores were settled in the left lower part of the plot with minor contribution of pollution parameters and more importance
of DO on the first axis. Samples of autumn and spring did not fit a clear cut pattern.
Deceased 相似文献