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61.
地下水文地质特征影响因素研究可以为开展矿井充水防治工作提供依据。通过对渭北煤田铜川矿区鸭口煤矿的水文地质资料进行综合分析,分析认为:地表水与本区二水平涌水量之间具有一定的相关性,而老空积水则与之无明显的相关性;二叠系石千峰组、奥陶系峰峰组、石炭系太原组石英砂岩层和K2灰岩含水层均不是造成矿井充水的主要原因;上石盒子组中下部砂岩含水层造成5-2煤层充水的可能性较小,下石盒子组下部砂岩和山西组下部砂岩含水层可引起煤层顶板充水;中、小型断裂带可以成为矿井充水的良好通道;二水平冒裂带波及范围至山西组下部砂岩含水层,造成充水的可能性较小;封闭不良的钻孔可以导水,严重时可以造成矿井充水。研究结论可为合理有效的开展矿井水防治工作提供一些理论依据。  相似文献   
62.
刘洁  陈华  王金星  陈星  李天元 《水文》2013,33(3):1-4
以淮河和珠江流域为研究对象,收集了淮河18个和珠江16个水文站19512010年长系列日流量资料。通过年极大值取样,应用线性矩法估计参数,比较分析了P-Ⅲ、对数P-Ⅲ和GL分布曲线在两个流域洪水频率分析计算情况。研究结果表明,对于小概率事件,在这两个流域对数P-Ⅲ和GL分布曲线设计洪水值要大于P-Ⅲ曲线分布计算的值,而通过误差分析,P-Ⅲ曲线的误差整体上小于对数P-Ⅲ曲线。  相似文献   
63.
Foliated garnet-bearing granite, usually associated with high pressure and ultrahigh -pressure (UHP) metamophic rocks, is a particular rock-type extensively exposed in the Mesozoic Dabie-Sulu orogenic belt of China. This study focuses on deformation features and SHRIMP zircon dating of foliated garnet granite in a high-pressure metamorphic unit from Huwan, western Dabie Mountains in order to resolve discrepancies in current versions of its petrogenesis and structural evolution. SHRIMP dating reveals a zircon age of 762 ± 15 Ma (MSWD=1.7) for Huwan granites, representing the Middle to Late Neoproterozoic age of intrusion and crystallization. Field and microstructural studies show that the Huwan granite body underwent multiple-stage deformation. The deformation was manifested by an early stage of rootless folding and imposition of relict foliation (S1); an Indosinian main stage marked by imposition of north-dipping penetrative gneissosity (S2) and development of ductile shear zones under NNE-SSW directed compression; and a final Indosinian stage of southward thrusting of the Huwan high-pressure unit. Shallow level extension prevailed after the Late Triassic, giving rise to south-dipping thrust faults and north-dipping normal faults. Supported by the National Natural Science Foundation of China (Grant Nos. 40802046 and 40334037) and the Project of Science & Technology Research and Development from Sinopec (Grant No. P02009)  相似文献   
64.
80年代以来 ,肝胰脏细小病毒病在养殖中国对虾中广泛流行并造成了一定的损失。作者采用免疫金银染色 (immunogold silver staining,IGSS)技术 ,对患病对虾肝胰脏中的细小病毒(Hepatopancreatic parvovirus,HPV)进行了免疫组织化学的研究。结果表明 ,经 IGSS染色的病虾肝胰脏上皮细胞核内出现了黑色的、圆形或椭圆形、大小为 3~ 15μm的结构。由于该结构与 H- E染色切片上出现的肝胰脏细小病毒包涵体在发生部位、形态和大小上皆一致 ,故而认为该结构为HPV包涵体。证明 ,免疫金银染色法是一种可应用于中国对虾肝胰脏细小病毒病诊断的有效方法。  相似文献   
65.
在ERDAS软件的支持下,对吐哈盆地相邻的两幅ETM遥感图像采用所介绍的直方图加减均值差和方差均值2种方法进行辐射匹配,并得出基于这2种方法的几点结论用于提高辐射匹配程度。同时为了降低匹配时存在的人为误差,提出了一种新的多样本均值的辐射匹配方法。最后通过对3种匹配方法的结果进行定量性检验,证明多样本均值的辐射匹配方法能达到较好的匹配效果,其匹配结果要优于前2种方法,具有可行性。笔者的目的在于:经过对不同方法的运用、对比及验证,提出了一种更为优越的辐射匹配方法———多样本均值法,以用于对吐哈盆地整体的辐射匹配。较好的匹配效果有助于对盆地内一些相关指数的准确评价和其砂岩型铀矿的分析研究。  相似文献   
66.
Adding building labels greatly improves the recognizability of buildings and the readability of three-dimensional (3D) city scenes. However, building label placement is much more complex in 3D scenes than in two-dimensional (2D) maps. The annotation effect is influenced by the attributes of the 3D label, building visibility, and the spatial relationship between the building and viewpoint. In this context, automatically generating building labels for 3D scenes during interactions requires highly complex computations. By contrast, evaluating candidate labels and then selecting the suitable label for each building can be effectively implemented. This paper introduces an approach for labeling buildings in 3D scenes based on evaluations of label candidates. The proposed method predefines a candidate label set for each building. These candidates are then evaluated in terms of their attributes and the relationship between the labels and viewpoint at runtime. The best candidate label, or a situational alternative for each building, is then placed in order of comprehensive label priority to avoid annotation conflicts. A series of experiments demonstrate that this method effectively enhances the correlation of labels and buildings, improves interactive efficiency, and realizes a viable global label layout.  相似文献   
67.
Wang  Qian  Su  Xianbo  Su  Linan  Guo  Hongyu  Song  Jinxing  Zhu  Zengliang 《Natural Resources Research》2020,29(6):3873-3893

Pseudo-reservoir stimulation in horizontal well is an effective technique for indirectly extracting coalbed methane (CBM) in soft coal from the surrounding rocks (pseudo-reservoir). However, systematic studies of the theory and on-site application of this technique are still lacking, which severely hinders its application. In this paper, the technical principles of pseudo-reservoir stimulation are analyzed firstly, and then, the technical advantages are demonstrated by experimental tests and theoretical analysis. The results show that the pseudo-reservoir generally possesses considerable gas adsorption capacity, with the gas content of 1.56–4.22 cm3/g (avg. 2.51 cm3/g) in Well XC-01, which can be extracted as supplementary resources. The fracability of the pseudo-reservoirs is 0.73–0.92, which is much higher than that of the coal seam, i.e., 0.03–0.43. Meanwhile, the compressive and tensile strength and cohesion of the pseudo-reservoir are higher than those of the coal seam, indicating pseudo-reservoir stimulation is more conducive to forming fracture network, and maintaining wellbore stability and fracture conductivity. The technical feasibility of pseudo-reservoir stimulation is determined by the regional geological conditions, showing simple tectonic conditions and well-developed surrounding rocks with high fracability and mechanical strength but low permeability, water sensitivity and water content are beneficial for the technique application. Note that the fracture conductivity in pseudo-reservoir is more stable and higher than that in coal seam, pseudo-reservoir stimulation is beneficial for the CBM extraction from both hard and soft coal seams. By minimizing the gas diffusion distance, this technique overcomes the technical obstacles to the CBM commercialized production in soft coal.

  相似文献   
68.
针对考虑传感器故障的柔性航天器姿态系统,提出了一种主动容错控制方法.首先,通过对测量输出进行滤波,将传感器故障转化为执行器故障形式;接着,设计一个基于未知输入观测器的自适应故障估计观测器,对未知故障进行辨识,同时,采用了一个故障检测观测器,对故障的发生进行检测;然后,利用故障估计信号对系统输出进行调节,结合自适应积分滑模和线性矩阵不等式技术设计输出反馈容错控制器;最后,对所设计的主动容错控制方法进行仿真,验证了所提方法的有效性.  相似文献   
69.
The wide application of antibiotics in aquaculture requires an efficient treatment of the wastewater before discharging it into the environment. During the wastewater treatment, the influence of antibiotics on the performance of bioreactor should be well revealed due to their toxicity to the functional microbial community. In this study, the effect of feeding 10-30 mg L~(-1) sulfamethoxazole(SMX) in influent on the performance of an anoxic/oxic-moving bed biofilm reactor(A/O-MBBR) treating mariculture wastewater and the responding change of biofilm microbial communities was investigated. The COD average removal rate remained at 94.61%-97.34% with the dosage of SMX. Compared with that, the nitrifying removals of NH_4~+-N and NO_2~--N were violently inhibited by 30 mg L~(-1) SMX and denitrifying removal of the NO_3~--N decreased obviously with 20 mg L~(-1) or more SMX. The microbial community in the successful startup bioreactor was relatively abundant, while the diversity of microbial community decreased with the increase of feeding SMX. The salt-tolerant and SMX-resistant genera Arcobacter, Thiothrix, Desulfuromusa and Nitrosomonas were gradually enriched and finally played a vital role in converting COD and recycling nitrogen and sulfur. Hence, the present A/O-MBBR reactor with the salt-tolerant functional microbiota achieved efficient removal of pollutants in the presence of low concentration(e.g., 10 mg L~(-1)) SMX.  相似文献   
70.
The paper studies CO2 degassing and controlling factors under the condition of contact metamorphism in the Shuangshan area, southern Tan-Lu fault belt and the method of calculating the amount of CO2 degassing. The results show that the amount of CO2 degassing is controlled by the characteristics of the country rocks, including the thermal conductivity, penetrability, porosity and connectivity. Compositions, size and depth of intrusive rock also have an important influence on CO2 degassing, i.e., they generated numerous cracks in the country rocks, and thus allowed the easy flow and accumulation of fluids. The amount of CO2 flux in contact metamorphism is calculated quantitatively based on the metamorphic reaction and time-integrated fluid flux. The value (0.729- 2.446×10^4 mol/cm^2) of CO2 flux suggests that CO2 was provided mainly by the contact metamorphic reaction. The generation and releasing of CO2 are positively correlated with the degree of metamorphism, and XCO2 in fluids gradually increases from dolomite zone to calcite zone, but in the zone of grossular, fluid flux is the largest and XCO2 sharply decreases due to involvement of magmatic water. This study presents evidence that a large amount of industrial-scale CO2 can be produced during contact metamorphism. On the basis of theoretical and practical studies, a cone model has been proposed to response CO2 degassing for the contact metamorphism, and it can be used to explore CO2 accumulations beyond the oil-gas basins. This model can also be applied to the study of inorganic genesis of CO2 accumulations.  相似文献   
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