Full-scale pore characteristics in coal and their influence on the adsorption capacity of coalbed methane.

Coalbed methane (CBM) is primarily stored and transported through the pores in the coal matrix, making it essential to study the development of different scales of pores in coal to better understand the evaluation and exploration of CBM. In this study, four coal samples of varying ranks (R = 0.68%-2.

Selection Effect of Liquid Nitrogen Freeze-Thaw Cycles on Full Pore Size Distribution of Different Rank Coals.

In China, the capacity to produce coalbed methane and extract underground gas is restricted by the prevalence of low-permeability coal seams. Liquid nitrogen fracturing is a new low temperature-high-pressure anhydrous fracturing technology that uses low temperature and high frost heave forces to increase coal permeability. To better understand the liquid nitrogen fracturing effect on coal, we conduct the liquid nitrogen freeze-thaw cycle (LNCFT) experiments on different rank coals from Qinghai, Shanxi, and Shaanxi provinces.

Nanopore Structure and Origin of Lower Permian Transitional Shale, Eastern Ordos Basin, China.

Nanopores in the shale play a vital role in methane adsorption, and their structural characteristics and origins are of great significance for revealing the mechanism of methane adsorption, desorption, and diffusion. In this paper, through low-temperature ashing and low-pressure gas adsorption experiments, the nanopore structure of original shales and ashed shales was quantitatively characterized, and the nanopore origins in the transitional shale of lower Permian in eastern Ordos Basin were analyzed. The results show that the pore volume (PV) and specific surface area (SSA) of nanopores in transitional shale reservoirs are 0.

Influence of Nanopore Structure Deformation on Gas Migration in Coal.

To better understand the influence and control of nanopore characteristics on gas migration, three kinds of coal samples with different metamorphic degrees were selected for the experiments including high-pressure isothermal gas adsorption, low-pressure CO adsorption, and low-pressure Ar adsorption. The changes of the pore volume (PV) and specific surface area (SSA) of coal samples before and after adsorption-desorption were compared and analyzed. The adsorption data of all coal samples at a low pressure stage (<8 MPa) conformed to the Langmuir equation, and the adsorption capacity of powdered coal samples was higher than that of columnar coal samples.

Effects of Early Pollution Control Measures on Secondary Species of PM in Jiaozuo, China.

Various measures for reducing air pollution have been promulgated since 2013 in China. To investigate the synergistic results of emission control and meteorological environment, PM samples collected from October 2013 to July 2016 and November 2018 to October 2019 in Jiaozuo city were analyzed for their compositions, secondary species (Ss) variations, and factors changing for Ss formation. The results showed that the concentrations of sulfate, nitrate, ammonium, and secondary organic aerosols (SOAs) generally decreased over the same seasonal period during these years.

Control Mechanism of the Effective Stress on Nano-Micro Pores and the Permeability of High-Rank Coals.

To study the change and main control factors of the high-rank coal reservoir permeability in deep coal seams, permeability tests under different stresses and gas pressures were carried out in the laboratory. The development and distribution of nano-micro pores and fractures in the coal matrix were analyzed and observed by mercury intrusion porosimetry, gas adsorption, scanning electron microscope and computed tomography to reveal the permeability variation mechanism. The results showed that the initial permeability of the coal samples ranged from 0.

Applicability Analysis of Determination Models for Nanopores in Coal Using Low-Pressure COâ‚‚ and Nâ‚‚ Adsorption Methods.

The development characteristics of nanopores (with pore sizes <200 nm) in coal are a key factor affecting the accumulation and migration of coalbed methane (CBM). Thus, an appropriate determination method and calculation model are essential for accurate nanopore representation. Based on the experiments of low-pressure COâ‚‚ adsorption (LP-COâ‚‚GA) at 273 K and low-pressure Nâ‚‚ adsorption (LP-Nâ‚‚GA) at 77 K on four coals with different ranks, the abilities of different models (e.

Selection and Validation of Appropriate Reference Genes for Quantitative Real-Time PCR Normalization in Staminate and Perfect Flowers of Andromonoecious .

Quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) is the most commonly used and powerful method for gene expression analysis due to its high sensitivity, specificity, and high throughput, and the accuracy of this approach depends on the stability of reference genes used for normalization. Yu and Li (Rosaceae), an andromonoecious plant, produces both bisexual flowers and unisexual male flowers within the same individual. Using qRT-PCR technique, investigation of the gene expression profiling in staminate and perfect flowers would improve our understanding of the molecular mechanism in regulation of flower formation and sex differentiation in andromonoecious .

The studying of washing of arsenic and sulfur from coals having different ranges of arsenic contents.

To study the effectiveness of washing in removal of arsenic and sulfur from coals with different ranges of arsenic concentration, coal was divided into three groups on the basis of arsenic content: 0-5.5 mg/kg, 5.5 mg/kg-8.

Contents and occurrence of cadmium in the coals from Guizhou province, China.

Eleven raw coal samples were collected from Liuzhi, Suicheng, Zunyi, Xingren, Xingyi, and Anlong districts in Guizhou Province, Southwest China. The content of cadmium (Cd) in coal was determined using inductively coupled plasma mass-spectrometry (ICP-MS). Cd contents ranged from 0.