Search

Lithium in coal, as a new type of associated mineral resource, has considerable potential for exploration. Exploration of high-lithium coal seams is essential for developing and using the associated lithium resources. To explore the distribution of lithium resources in the early stages of development in coal seams, the relationship between coal seam logging data and lithium content was analyzed by taking Guojiadi Coal Mine (China) as example. By analyzing the correlation between the different logging curves and the lithium content in coal and combining the K-means algorithm to identify the logging characteristics of different lithium-containing coal seams, we finally obtained the logging identification characteristics of high-lithium coal seams. The results reveal differences in the logging curves of coal seams with different lithium contents. The natural gamma and lateral resistivity of high-lithium coal seams are approximately 80 API and 100 Ω.M, respectively. Our study shows that the early identification of high-lithium coal seams can be evaluated from a logging perspective. We propose a preliminary identification method of high-lithium coal seam based on logging curve parameters by clustering analysis of borehole logging data to achieve accurate prediction.

To study the characteristics of coupled accumulation and determine the geological control effects on coal measures gases (CMGs), coal measures of the Carboniferous-Permian Taiyuan and Shanxi formations at Qinshui Basin were selected as the target formations. Various methods including field data collection, field/lab measurements, and theoretical analyses were applied to described the spatial superposition of CMG reservoirs, quantitatively determine the multi-scale pore system, identify the spatial development pattern of CMGs gas-bearing section, and clarify the types of CMGs coupled accumulation and geological controls. Results show that coal measures deposited at the unique marine-terrigenous depositional environment was characterized by lithological diversity and cyclic superposition which was served as the potential basics for coupled accumulation and co-exploration/development of CMGs. The abundance of the organic matter gradually increased from the “inorganic reservoir” to “organic reservoir”, forming a continuous rock sequence without a natural boundary in target coal measures. Gas-bearing sections was characterized by a vertically intermittent distribution and the dominant coupled accumulation assemblages can be subdivided into: shale gas dominated coupled accumulation type, CBM dominated coupled accumulation type, and multiple CMGs coupled accumulation type. Obviously, the effective gas-bearing sections need the appropriate combination of source, reservoir and cap. Coal reservoirs directly controlled the distribution of effective gas-bearing section. Reservoir burial conditions restricted the possibility of an effective gas-bearing section. Moreover, coals were believed to be more favorable for independent coalbed methane accumulation, whereas shale gas and sandstone gas required extremely strict geological, spatial and temporal conditions. Additionally, both organic-inorganic fabric and physical characteristics limited the potential of effective gas-bearing sections. Inspired by the findings of this study, further studies on the coupled accumulation mechanism and the co-exploration evaluation system of CMGs should be continuously conducted.

Abstract In tonal languages, which are spoken by nearly one-third of the world’s population, speakers precisely control the tension of vocal folds in the larynx to modulate pitch in order to distinguish words with completely different meanings. The specific pitch trajectories for a given tonal language are called lexical tones. Here, we used high-density direct cortical recordings to determine the neural basis of lexical tone production in native Mandarin-speaking participants. We found that instead of a tone category-selective coding, local populations in the bilateral laryngeal motor cortex (LMC) encode articulatory kinematic information to generate the pitch dynamics of lexical tones. Using a computational model of tone production, we discovered two distinct patterns of population activity in LMC commanding pitch rising and lowering. Finally, we showed that direct electrocortical stimulation of different local populations in LMC evoked pitch rising and lowering during tone production, respectively. Together, these results reveal the neural basis of vocal pitch control of lexical tones in tonal languages.

In order to study the adsorption process and adsorption characteristics of shale oil at the macro scale, the isothermal adsorption experiments of illite and kerogen on a heptadecane (oil phase) solution were carried out by infrared spectrophotometry and gas chromatography–mass spectrometry. Based on the adsorption isotherm model and adsorption thermodynamic model, the characteristics of heptadecane adsorbed by illite and kerogen at different temperatures and oily solution concentrations were studied. The experimental results show that the concentration and temperature of the alkane solution help to enhance the adsorption and increase the saturated adsorption capacity. The difference is that the concentration will have a certain effect on the adsorption rate, while the temperature will not. Based on the three adsorption isotherm models, it was found that Langmuir and Freundlich were more suitable for describing the adsorption process of the heptadecane solution by illite and kerogen, and the adsorption characteristics of heptadecane molecules at different temperatures and adsorbents were evaluated. Heating leads to an increase in the collision efficiency between adsorbate molecules and adsorbents, thereby accelerating the migration rate of alkanes. Therefore, increasing temperature helps to enhance the adsorption capacity of rocks and increase the saturated adsorption capacity of minerals. The research results clarify the adsorption characteristics of shale oil heavy components from the macro level and fill the research gap in the application of solid–liquid isothermal adsorption physical experiments on the adsorption and occurrence of shale oil.

The shales of the Taiyuan Formation and Shanxi Formation in the North China Basin have good prospects for shale gas exploration and development. In this study, Well KP1 at the northern margin of the North China Basin was used as the research object for rock mineral, organic geochemical, and elemental geochemical analyses. The results show that brittle minerals in the shales of the Taiyuan Formation and Shanxi Formation are relatively rare (50%). The average TOC content is 3.68%. The organic matter is mainly mixed and sapropelic. The source rocks of the Taiyuan Formation and Shanxi Formation are mainly felsic, and the tectonic background lies in the continental island arc area. The primary variables that influenced the enrichment of organic materials during the sedimentary stage of the Taiyuan Formation were paleosalinity and paleoproductivity. Paleosalinity acted as the primary regulator of organic matter enrichment during the sedimentary stage of the Shanxi Formation.

Abstract Segmentation of white matter tracts in diffusion magnetic resonance images is an important first step in many imaging studies of the brain in health and disease. Similar to medical image segmentation in general, a popular approach to white matter tract segmentation is to use U-Net based artificial neural network architectures. Despite many suggested improvements to the U-Net architecture in recent years, there is a lack of systematic comparison of architectural variants for white matter tract segmentation. In this paper, we evaluate multiple U-Net based architectures specifically for this purpose. We compare the results of these networks to those achieved by our own various architecture changes, as well as to new U-Net architectures designed automatically via neural architecture search (NAS). To the best of our knowledge, this is the first study to systematically compare multiple U-Net based architectures for white matter tract segmentation, and the first to use NAS. We find that the recently proposed medical imaging segmentation network UNet3+ slightly outperforms the current state of the art for white matter tract segmentation, and achieves a notably better mean Dice score for segmentation of the fornix (+ 0.01 and + 0.006 mean Dice increase for left and right fornix respectively), a tract that the current state of the art model struggles to segment. UNet3+ also outperforms the current state of the art when little training data is available. Additionally, manual architecture search found that a minor segmentation improvement is observed when an additional, deeper layer is added to the U-shape of UNet3+. However, all networks, including those designed via NAS, achieve similar results, suggesting that there may be benefit in exploring networks that deviate from the general U-Net paradigm.

The object of the study is lignite. Analytical testing techniques, such as elemental analysis, 13C nuclear magnetic resonance (13C NMR) spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM), were used to acquire information on the structural parameters of lignite. The aromaticity of Xianfeng lignite is 43.57%, and the aromatic carbon structure is mainly naphthalene and anthracene/phenanthrene. The aliphatic carbon structure is dominated by cycloalkanes, alkyl side chains, and hydrogenated aromatics. Oxygen is mainly present in ether oxygen, carboxyl, and carbonyl groups. Nitrogen is mainly in the form of pyrrole nitrogen and quaternary nitrogen. Sulfur is mainly thiophene sulfur. According to the analysis results, the molecular structure model of XF lignite was constructed. The molecular formula is C184H172O39N6S2. The 2D structure was converted to a 3D structure using computer simulation software and optimized. The optimized model has a remarkable stereoconfiguration, and the aromatic lamellae are irregularly arranged in space. The aromatic rings were mainly connected by methylene, hypomethylene, methoxy, and aliphatic rings. In addition, the simulated 13C NMR spectra are in good agreement with the experimental spectra. This shows the rationality of the 3D chemical structure model.

Abstract Large-size scintillators with high efficiency and ultrafast radiation fluorescence have shown more potential in the applications to ionizing radiation detection of medical diagnosis, nuclear control and high-energy physics. Currently, although traditional scintillators have made tremendous progress in scintillation efficiency, there are still challenges left in fluorescence lifetime. Faced with that problem, we adopted 2-inch ZnO as the substrate and doped gallium as activator to realize an ultrafast fluorescence excited by α-ray, of which the decay time is only 600 ps that is the shortest scintillation decay time reported so far. The results show that the shallow donor related with gallium not only effectively suppresses band-edge self-absorption, but makes ultrafast radiation possible, which gets gallium-doped ZnO as a potential scintillator for high-quality ultrafast dynamic imaging proved.

Smart grids are vulnerable to stealthy false data injection attacks (SFDIAs), as SFDIAs can bypass residual-based bad data detection mechanisms. Methods based on deep learning technology have shown promising accuracy in the detection of SFDIAs. However, most existing methods rely on the temporal structure of a sequence of measurements but do not take account of the spatial structure between buses and transmission lines. To address this issue, we propose a spatiotemporal deep network, PowerFDNet, for the SFDIA detection in AC-model power grids. The PowerFDNet consists of two sub-architectures: spatial architecture (SA) and temporal architecture (TA). The SA is aimed at extracting representations of bus/line measurements and modeling the spatial structure based on their representations. The TA is aimed at modeling the temporal structure of a sequence of measurements. Therefore, the proposed PowerFDNet can effectively model the spatiotemporal structure of measurements. Case studies on the detection of SFDIAs on the benchmark smart grids show that the PowerFDNet achieved significant improvement compared with the state-of-the-art SFDIA detection methods. In addition, an IoT-oriented lightweight prototype of size 52 MB is implemented and tested for mobile devices, which demonstrates the potential applications on mobile devices. The trained model will be available at [Online]. Available: https://github.com/FrankYinXF/PowerFDNet.

Abstract Phasor measurement units (PMUs) have been widely deployed in power grids, while the bad PMU data problem threatens power system monitoring and control. This paper first gives the objective of the bad PMU data detection and gives an illustrative bad data instance. Then, the time‐series PMU data of neighbouring buses are cast as a two‐dimensional diagram, of which the spatio‐temporal correlation analysis is performed to design the normal and outlier data detection problem. Three clustering methods, including linear regression, density‐based spatial clustering of applications with noise (DBSCAN), and Gaussian mixture models (GMM) are ensembled for bad PMU data detection. Moreover, the statistical analysis and bound modification of data clustering are developed to further improve the detection accuracy. Finally, the procedure of the two‐stage bad PMU data detection is given, which consists of ensemble learning and modification. The proposed hybrid clustering‐based bad data detection is unsupervised and is applied to online bad PMU data detection with a short computation time. Visible and numerical case study results validate the outperformance of the proposed method.

Contactless fingerprint biometrics has achieved rapid development in the past decades thanks to its inherent advantages, such as no physical contact between a finger and a sensor, no contamination by latent fingerprints, and more hygienic. These advantages have paved the way for new 2D or 3D contactless fingerprint-based applications and have promoted a larger number of academic publications in recent years. Therefore, it is necessary and important to conduct a comprehensive survey on contactless fingerprint biometric technology, review the latest research findings on 2D and 3D contactless fingerprint recognition systems, and point out the future development direction of contactless fingerprint biometrics. In this work, a comprehensive survey is presented to review the 2D and 3D contactless fingerprint biometrics from four essential aspects: contactless fingerprint capture, fingerprint preprocessing, feature extraction, and template comparison. To serve as a good reference, we provide a well-structured taxonomy about contactless fingerprint biometrics. We also identify related research problems and future research directions.

Phosphorescence emission from extrinsic rare-earth element and organic component remains a challenge. Here, the authors demonstrate an ultraviolet ultralong intrinsic phosphorescence (UIP, >20,000 seconds) in aluminum nitride (AlN) single-crystal scintillator through X-ray excitation.

Deep learning has become a predominant method for solving data analysis problems in virtually all fields of science and engineering. The increasing complexity and the large volume of data collected by diverse sensor systems have spurred the development of deep learning methods and have fundamentally transformed the way the data are acquired, processed, analyzed, and interpreted. With the rapid development of deep learning technology and its ever-increasing range of successful applications across diverse sensor systems, there is an urgent need to provide a comprehensive investigation of deep learning in this domain from a holistic view. This survey paper aims to contribute to this by systematically investigating deep learning models/methods and their applications across diverse sensor systems. It also provides a comprehensive summary of deep learning implementation tips and links to tutorials, open-source codes, and pretrained models, which can serve as an excellent self-contained reference for deep learning practitioners and those seeking to innovate deep learning in this space. In addition, this paper provides insights into research topics in diverse sensor systems where deep learning has not yet been well-developed, and highlights challenges and future opportunities. This survey serves as a catalyst to accelerate the application and transformation of deep learning in diverse sensor systems.

A shale lithofacies scheme is commonly used to characterize source rock reservoirs of the Lower Cambrian Niutitang Formation. However, this classification ignores that individual components such as quartz may have different origins, potentially affecting reservoir quality. The main objective of this article is, therefore, to present a refined scheme for lithofacies and an image processing workflow for the detection of quartz types in the Niutitang Formation shales from the Jiumen outcrop in the Guizhou Province (Upper Yangtze Basin, SW China). In order to do so, a combination of bulk density, optical and scanning electron microscopy and image analysis was used. The shale lithology was macroscopically classified into seven major categories and nineteen subcategories. Subsequently, the shales were investigated at the microscopic level, mainly focusing on quartz types and microstructural variations. Afterwards, the workflow to calculate the weight per unit volume (1 cm3) of the quartz types was presented, i.e., firstly, by calculating the weight of mineral matter by subtraction of the measured weight of organic matter from the bulk shale; secondly, by calculating the weight of total quartz in bulk shale from the weight of mineral matter and its proportion calculated from X-ray diffraction data; thirdly, by calculating the weight of detrital quartz and non-detrital quartz with energy dispersive X-ray mapping, image processing and quartz density; finally, by calculating the weight of clay-sized quartz by subtracting of the weight of detrital and non-detrital quartz from the weight of the total quartz. The bulk quartz content was found to be dominated by clay-sized quartz, which may mainly control the mesopore volume available for gas storage and, hence, the shale gas reservoir development.

Cognitive biometrics is an emerging branch of biometric technology. Recent research has demonstrated great potential for using cognitive biometrics in versatile applications, including biometric recognition and cognitive and emotional state recognition. There is a major need to summarize the latest developments in this field. Existing surveys have mainly focused on a small subset of cognitive biometric modalities, such as EEG and ECG. This article provides a comprehensive review of cognitive biometrics, covering all the major biosignal modalities and applications. A taxonomy is designed to structure the corresponding knowledge and guide the survey from signal acquisition and pre-processing to representation learning and pattern recognition. We provide a unified view of the methodological advances in these four aspects across various biosignals and applications, facilitating interdisciplinary research and knowledge transfer across fields. Furthermore, this article discusses open research directions in cognitive biometrics and proposes future prospects for developing reliable and secure cognitive biometric systems.

Summary: Mitochondrial DNA (mtDNA) segregation associated with donor-recipient mtDNA mismatch in mitochondria replacement therapy leads to unknown risks. Here, to explore whether matching mtDNA haplotypes contributes to ameliorating segregation, we reproduced various degrees of heteroplasmic mice with three single nucleotide polymorphisms to monitor segregation severity. “Segregation” presented in tissues of heteroplasmic mice containing low-level donor mtDNA heteroplasmy, and disappeared as donor mtDNA heteroplasmy levels ascended. Meanwhile, we found that distribution of donor mtDNA among the blastomeres of preimplantation embryos from the heteroplasmic mice shared the same tendency as that in adult tissues. Statistical analysis showed that no selective replication of donor mtDNA occurred during lifespan. Tracking donor mtDNA distribution showed that uneven distribution of donor mtDNA among embryonic blastomeres gradually became even as donor mtDNA heteroplasmy increased, indicating that the “segregation” in tissues was inherited from the uneven distribution. Our finding suggested that donor-recipient mtDNA matching could circumvent segregation in mitochondria replacement therapy. : Biological Sciences; Developmental Genetics; Genetics Subject Areas: Biological Sciences, Developmental Genetics, Genetics

Abstract Background Even though bicarbonate alkaline stress is a serious threat to crop growth and yields, it attracts much fewer researches than high salinity stress. The basic leucine zipper (bZIP) transcription factors have been well demonstrated to function in diverse abiotic stresses; however, their biological role in alkaline tolerance still remains elusive. In this study, we functionally characterized a bZIP gene from Glycine soja GsbZIP67 in bicarbonate alkaline stress responses. Results GsbZIP67 was initially identified as a putative bicarbonate responsive gene, on the basis of previous RNA-seq data of 50 mM NaHCO3-treated Glycine soja roots. GsbZIP67 protein possessed a conserved bZIP domain, and belonged to the group S2 bZIP, which is yet less well-studied. Our studies showed that GsbZIP67 targeted to nucleus in Arabidopsis protoplasts, and displayed transcriptional activation activity in yeast cells. The quantitative real-time PCR analyses unraveled the bicarbonate stress responsive expression and tissue specific expression of GsbZIP67 in wild soybean. Further phenotypic analysis illustrated that GsbZIP67 overexpression in alfalfa promoted plant growth under bicarbonate alkaline stress, as evidenced by longer roots and shoots. Furthermore, GsbZIP67 overexpression also modified the physiological indices of transgenic alfalfa under bicarbonate alkaline stress. In addition, the expression levels of several stress responsive genes were also augmented by GsbZIP67 overexpression. Conclusions Collectively, in this study, we demonstrated that GsbZIP67 acted as a positive regulator of plant tolerance to bicarbonate alkaline stress. These results provide direct genetic evidence of group S2 bZIPs in bicarbonate alkaline stress, and will facilitate further studies concerning the cis-elements and/or downstream genes targeted by GsbZIP67 in stress responses.

Tectonism is one of the major controlling factors of shale gas accumulation and enrichment in China. To explore the relationship between tectonism and composition and pore characteristics of shale reservoirs, this research carried out mineralogy tests, organic geochemistry tests, field emission scanning electron microscopy (FE-SEM) experiments, and low-pressure gas adsorption (LPGA, N2 and CO2) experiments on the shale samples of various deformation intensities from Southwestern China. Based on the FE-SEM image analyses, it can be found that there are large differences in pore characteristics in shale samples with different deformation intensities. The samples with strong deformation have more organic pores, mainly related to the clay-organic aggregates and rigid grains. Tectonism can cause organic matter (OM) and clay minerals to be mixed or OM to fill in the clay layers, resulting in the retention of some organic pores. It is the presence of pressure shadows around the rigid grains that can resist tectonic extrusion and protect some organic pores. LPGA experiment results also show that micropore-specific surface areas and pore volumes of the samples with strong deformation are larger than those with weak deformation. The shale samples with strong deformation also have more microchannels and microfractures. Tectonism can also cause some micropores to become macropores; for example, tectonism can cause the rigid grains to slide and rotate, enlarging the dissolution pores at the edges of rigid grains. Shale samples with strong deformation have a smaller mesopore volume; but due to the presence of organic-clay aggregates, a larger mesopore-specific surface area embarks on these samples. According to fractal dimension calculations, it is found that in strong deformed shale, more multiple dimensions of the pore system tend to represent rougher pore surfaces and more irregular shapes. Besides, rougher pore surfaces are eager to provide more adsorption sites and enhance the adsorption capacity of the deformed shale. This study investigates the relationship between tectonism and composition and pore characteristics of shale reservoirs and may promote understanding of the accumulation of shale gas in highly deformed areas.

Geological prediction models for gas content in marine–terrigenous shale under the effects of reservoir characteristics and in situ geological conditions, were established using methane isothermal adsorption, high temperature/pressure methane isothermal adsorption, total organic carbon, X-ray diffraction, mercury porosimetry, porosity in net confining stress, and field desorption methods. Results indicated that the adsorption capacity of marine–terrigenous shale has a linearly positive correlation with total organic carbon content and maturity. Clay and quartz minerals are the two main components of inorganic minerals in marine–terrigenous shale, with an average content of 54.3% and 36.9%, respectively. Adsorption capacity of marine–terrigenous shale is slightly positive correlated with clay content, while it exponentially decreases with increasing quartz content. The effects of in situ temperature and reservoir pressure on adsorption capacity in marine–terrigenous shale are also significant. The adsorption capacity of marine–terrigenous shale shows a clear decreasing trend as temperature increases, while it increases with increasing reservoir pressure. The porosity of marine–terrigenous shale is characterized by highly stress-sensitive, decreasing exponentially with increasing effective stress, which results in a more complex occurrence of free gas in deep shale reservoirs. In addition, gas saturation for the shale samples was calculated based on the results of field desorption, after which geological prediction models of total gas, adsorbed gas, and free gas were established while considering the coupled effects. Adsorbed gas, free gas, and total gas content all initially increase as burial depth increases, and then eventually decrease. Adsorbed gas content and free gas content have a positive correlation with total organic carbon content and porosity, indicating that the total gas content at different burial depths is mainly controlled by the total organic carbon content and porosity.

Up to now, the influence of unintentionally doped H in ZnO on electronic properties still perplexes us. Recently, it had been found in experiment that the introduction of Li would dramatically decrease the stability of H. In order to clarify the inner physical mechanism behind the phenomenon, we investigated the formation energy and the potential barrier height for H movement in ZnO with different configuration of doped Li by employing first-principle calculation. It is revealed that interstitial Li (Lii) facilitates the escape of H from trap of ZnO lattice and reduces the potential barrier due to electrostatic interaction. Our methodology can also be extended to analyze the stability of trace element in other semiconductors.

The shale gas enrichment pattern of Well Wuxi-2 in northeast Chongqing was studied, based on the data of the drilling, graptolite biostratigraphy, geochemistry, rock minerals, microscopic characteristics of reservoir beds and tectonic conditions, etc. The organic-rich shale of Upper Ordovician Wufeng Formation—Lower Silurian Lungmachi Formation is 89.8 m thick in Well WX-2. The graptolite biozonations are completely developed in this well, and the organic-rich shale intervals extend upward from the late Katian of the Ordovician to the early Telychian of the Lower Silurian. The deposition time of the organic-rich shale is far longer and the thickness is larger than those in other areas of the Sichuan Basin. The highest measured gas content exceeded 8 m3/t in Well WX-2, and the gas content is mainly controlled by TOC. The organic nano-pores are the main storage space, and the minerals contribute less to the storage space. The organic pores larger than 50 nm are well-developed and those less than 10 nm are the main reservoir space of adsorbed gas. The target intervals of Well WX-2 are located under the neutral surface of compressional Tianba anticline. Two vertical fracture (cleavage) development zones, which are beneficial for shale gas storage and complex fracture network formation during later fracturing, were formed in brittle layers of this organic-rich shale. Compressional faults existed in two limbs of the Tianba anticline, with non-permeable shale developing on both sides of fault planes and development of clay smear, which shows that the faults have good sealing properties, and are favorable for shale gas preservation. Thus the good match between the above various accumulation conditions forms the “tectonic sweet-spot” of shale gas in this study area. Key words: Well WX-2, shale gas, graptolite biostratigraphy, organic pore, tectonic sweet-spot, enrichment pattern

This study focuses on the nanostructure of shale samples with type III kerogen and its effect on methane adsorption capacity. The composition, pore size distribution, and methane adsorption capacities of 12 shale samples were analyzed by using the high-pressure mercury injection experiment, low-temperature N2/CO2 adsorption experiments, and the isothermal methane adsorption experiment. The results show that the total organic carbon (TOC) content of the 12 shale samples ranges from 0.70% to ~35.84%. In shales with type III kerogen, clay minerals and organic matter tend to be deposited simultaneously. When the TOC content is higher than 10%, the clay minerals in these shale samples contribute more than 70% of the total inorganic matter. The CO2 adsorption experimental results show that micropores in shales with type III kerogen are mainly formed in organic matter. However, mesopores and macropores are significantly affected by the contents of clay minerals and quartz. The methane isothermal capacity experimental results show that the Langmuir volume, indicating the maximum methane adsorption capacity, of all the shale samples is between 0.78 cm3/g and 9.26 cm3/g. Moreover, methane is mainly adsorbed in micropores and developed in organic matter, whereas the influence of mesopores and macropores on the methane adsorption capacity of shale with type III kerogen is small. At different stages, the influencing factors of methane adsorption capacity are different. When the TOC content is 4.5%, the methane adsorption capacity is positively correlated with the TOC content. When the TOC content is in the range of 1.4–4.5%, clay minerals have obviously positive effects on the methane adsorption capacity.

The overpressure phenomenon is a widespread occurrence in unconventional shale gas reservoirs. Multiple overpressure shale gas fields were discovered in southern China, and there is no doubt that the gas production per well increases with increasing pressure coefficient (the ratio of the reservoir fluid pressure to the corresponding normal hydrostatic pressure). Thus, successful evaluation and production strategies of organic-rich shale deposits require an understanding of the evolution of the pressure coefficient and its controlling factors in these deposits. In this paper, drilling engineering data of a typical well were collected, and clay mineral tests and overburden diffusion coefficient experiments were conducted. Based on multiphysics simulations, this paper analyzes the overpressure characteristics and formation mechanisms of overpressure in the Longmaxi Formation shale, as well as its geological evolution and controlling factors. The results show that the large amount of shale gas is the cause of overpressure formation rather than disequilibrium compaction. The simulation results show that pressure coefficients of the typical well range from 0.84 to 1.49. The current pressure coefficient increases with increasing pressure coefficient after the last hydrocarbon generation. A large initial pressure coefficient (>1.9), short lifting time (

To better understand the variability and heterogeneity of pore size distributions (PSDs) in the Longmaxi Shale, twelve shale samples were collected from the Xiaoxi and Fendong section, Sichuan Province, South China. Multifractal analysis was employed to study PSDs of mesopores (2−50 nm) and micropores (2/CO2 adsorption (LP-N2/CO2GA). The results show that the PSDs of mesopores and micropores exhibit a multifractal behavior. The multifractal parameters can be divided into the parameters of heterogeneity (D−10−D10, D0−D10 and D−10−D0) and the parameters of singularity (D1 and H). For both the mesopores and micropores, decreasing the singularity of the pore size distribution contributes to larger heterogeneous parameters. However, micropores and mesopores also vary widely in terms of the pore heterogeneity and its controlling factors. Shale with a higher total organic carbon (TOC) content may have a larger volume of micropores and more heterogeneous mesopores. Rough surface and less concentrated pore size distribution hinder the transport of adsorbent in mesopores. The transport properties of micropores are not affected by the pore fractal dimension.

Soil salt-alkalization is a dramatic challenging factor for plant growth. Wild soybean (Glycine soja) exhibits a favorable trait of superior tolerance to salt-alkali stress, and recent discoveries show that response regulator family genes are involved in diverse abiotic stresses. Genomic and transcriptomic analyses of all response regulator genes in wild soybean will provide insight into their function in plant stress response. In this study, we identified and characterized a total of 56 Glycine soja response regulator (GsRR) genes. Phylogenetic analysis suggested that GsRR genes could be classified into five subclasses (A1, A2, B1, B2, and C). We further investigated the chromosome locations, gene duplications and conserved domains of the GsRRs. Furthermore, the clustering analysis of GsRR transcript profiles revealed five different expression patterns under alkali stress. The A1 and A2 subclasses display significantly higher transcriptional levels than the B subclass. In addition, quantitative real-time PCR results verified that the GsRR genes were also significantly influenced by salt stress. Notably, GsRR2a in the A1 subclass showed opposite expression patterns under salt stress comparing with alkali stress. Moreover, overexpression of GsRR2a in Arabidopsis significantly improved the tolerance to alkali stress, but not salt stress. These results suggest the important roles of GsRR genes in response to salt and alkaline stresses, and also provide valuable clues for further functional characterization of GsRR family genes.

Receptor-like kinases (RLK) play fundamental roles in plant growth and stress responses. Compared with other RLKs, little information is provided concerning the S-locus LecRLK subfamily, which is characterized by an extracellular G-type lectin domain and an S-locus-glycop domain. Until now, the function of the G-type lectin domain is still unknown. In a previous research, we identified a Glycine soja S-locus LecRLK gene GsSRK, which conferred increased salt stress tolerance in transgenic Arabidopsis. In this study, to investigate the role of the G-type lectin domain and to breed transgenic alfalfa with superior salt stress tolerance, we transformed the full-length GsSRK (GsSRK-f) and a truncated version of GsSRK (GsSRK-t) deleting the G-type lectin domain into alfalfa. Our results showed that overexpression of GsSRK-t, but not GsSRK-f, resulted in changes of plant architecture, as evidenced by more branches but shorter shoots of GsSRK-t transgenic alfalfa, indicating a potential role of the extracellular G-type lectin domain in regulating plant architecture. Furthermore, we also found that transgenic alfalfa overexpressing either GsSRK-f or GsSRK-t showed increased salt stress tolerance, and GsSRK-t transgenic alfalfa displayed better growth (more branches and higher fresh weight) than GsSRK-f lines under salt stress. In addition, our results suggested that both GsSRK-f and GsSRK-t were involved in ion homeostasis, ROS scavenging, and osmotic regulation. Under salt stress, the Na+ content in the transgenic lines was significantly lower, while the K+ content was slightly higher than that in WT. Moreover, the transgenic lines displayed reduced ion leakage and MDA content, but increased SOD activity and proline content than WT. Notably, no obvious difference in these physiological indices was observed between GsSRK-f and GsSRK-t transgenic lines, implying that deletion of the GsSRK G-type lectin domain does not affect its physiological function in salt stress responses. In conclusion, results in this research reveal the dual role of GsSRK in regulating both plant architecture and salt stress responses.

The gas flow mechanisms in source rocks of coal measures under the effects of the pore structures and permeability characteristics were investigated by field-emission scanning electron microscopy, low-pressure nitrogen gas adsorption, high-pressure mercury intrusion, and pressure pulse decay permeability method. Various flow regimes were distinguished in the pores and fractures of differing scales, and the mass fluxes through the same were calculated using the data obtained by the numerical and experimental investigations. Results indicated that mesopores predominated in shale, while coal contained well-developed mesopores and macropores. In addition, the permeabilities of coal and shale were observed to be significantly anisotropic and highly stress dependent. The cross-sectional area proportions of the pores per unit cross-sectional area of the matrix in the free molecular, transition, and slip flow regimes in shale and coal were determined to be, respectively, 0.2:0.7:0.1 and 0.15:0.6:0.25. In the free molecular and transition flow regimes, the mass flux decreased with increasing reservoir depth, while the reverse was the case in the slip flow regime. Further, in the continuum flow regime, the mass flux was unimodally distributed with respect to the reservoir depth. The total mass flux in coal was greater in the direction perpendicular to the bedding compared to the direction parallel to the bedding, while the reverse was the case in shale. In addition, the continuum flow regime predominated in coal in both the directions perpendicular and parallel to the bedding, but only in the direction parallel to the bedding in shale. This work presents a comprehensive model for the analysis of all the flow regimes in pores and fractures of differing scales, as well as the anisotropy. Findings of the study are meaningful for establishing the coupling accumulation mechanism of the Three Coal Gases and developing a unified exploration and exploitation program.

The organic-enriched thick shale at the bottom of Longmaxi Formation is laterally continuous distributed and has been proven to be of good production capability in Fuling of Upper Yangtze. Uplifts that developed during the sedimentation influenced the reservoir characteristics by taking control of the sedimentary environment and provenance. The sedimentary environments are mainly deep-water shelf, shallow-water shelf, and tidal flat. By analyzing reservoir characteristic of these three environments, the deep-water shelf, which dominated the early stage of sedimentation, formed a high-quality reservoir with high TOC (Total Organic Carbon) content, porosity, and brittleness, while the environment was maintained around the basin centre until the Early Silurian. The shales deposited under the shallow-water environment were of low porosity because of the increasing calcareous and argillaceous contents. Sediments which formed on the tidal flat were arenaceous and of the lowest TOC content as the organic preservation conditions deteriorated. The good correlation of graptolite abundance and TOC content, and high porosity within graptolite fossils emphasize the importance of palaeontological development. The argillaceous cap over the Longmaxi shale is of good sealing capability, and the continuous sedimentation zone along southern Sichuan−eastern Chongqing is the best optimized hydrocarbon-bearing system. However, a weak interface on the discontinuity is the potential lateral pathway for gas diffusion at Northern Guizhou and Western Hunan, but on the southeast margin where the dark shale and the tidal sandstone contact, it promises to form a tight gas reservoir.

Following publication of the original article [1], the author reported that their given name was misspelled.

Gas flow mechanisms in shale reservoirs with multiscale pores and fractures are extremely complex. In this study, a dual fracture framework model was adopted to describe gas flow in multiscale shale reservoirs. Gas flow through a shale reservoir occurs through both the shale matrix and hydraulic fractures. This study considered bulk phase and adsorbed gas flow in the shale matrix. Next, a series of partial theories were combined to derive a fully coupled model simulating gas flow in multiscale shale reservoirs: (1) fractal theory was adopted to obtain the pore distribution within shale reservoirs; (2) mechanical equilibrium equations were used to investigate the stress-sensitivity of permeability and porosity; and (3) a Langmuir adsorption model was applied to describe the effects of gas adsorption/desorption. The proposed model was validated using traditional models as well as field data on gas production from Marcellus Shale, and was subsequently applied to study variations of mass flux in various flow regimes with respect to reservoir pressure. We found that mass flux in the slip flow regime decreased at first and then increased with decreasing reservoir pressure, while in the continuum regime, Knudsen diffusion and surface diffusion the mass flux decreased with decreasing reservoir pressure. Stress-sensitivity has a significant impact on bulk phase gas flow, while adsorption/desorption influence both the bulk phase gas flow and adsorbed gas flow. At high pressures, the impact of stress-sensitivity on total gas mass flux is greater than that of adsorption/desorption, while the reverse was true for low pressures. The proposed model shows promising applications for analyzing various gas flow regimes in multiscale pores/fractures, and accurately evaluating in situ apparent permeability.

Myo-inositol participates in various aspects of plant physiology, and myo-inositol oxygenase is the key enzyme of the myo-inositol oxygenation pathway. Previous studies indicated that myo-inositol oxygenase may play a role in plant responses to abiotic stresses. In this study, we focused on the functional characterization of GsMIOX1a, a remarkable alkaline stress-responsive gene of Glycine soja 07256, based on RNA-seq data. Using quantitative real-time PCR, we demonstrated that GsMIOX1a is rapidly induced by alkaline stress and expressed predominantly in flowers. We also elucidated the positive function of GsMIOX1a in the alkaline response in the wild type, atmiox1 mutant as well as GsMIOX1a-overexpressing Arabidopsis. We determined that atmiox1 mutant decreased Arabidopsis tolerance to alkaline stress, whereas GsMIOX1a overexpression increased tolerance. Moreover, the expression levels of some alkaline stress-responsive and inducible marker genes, including H+-Ppase, NADP-ME, KIN1 and RD29B, were also up-regulated in GsMIOX1a overexpression lines compared with the wild type and atmiox1 mutant. Together, these results suggest that the GsMIOX1a gene positively regulates plant tolerance to alkaline stress. This is the first report to demonstrate that ectopic expression of myo-inositol oxygenase improves alkaline tolerance in plants.

It is widely accepted that the 14-3-3 family proteins are key regulators of multiple stress signal transduction cascades. By conducting genome-wide analysis, researchers have identified the soybean 14-3-3 family proteins; however, until now, there is still no direct genetic evidence showing the involvement of soybean 14-3-3s in ABA responses. Hence, in this study, based on the latest Glycine max genome on Phytozome v10.3, we initially analyzed the evolutionary relationship, genome organization, gene structure and duplication, and three-dimensional structure of soybean 14-3-3 family proteins systematically. Our results suggested that soybean 14-3-3 family was highly evolutionary conserved and possessed segmental duplication in evolution. Then, based on our previous functional characterization of a Glycine soja 14-3-3 protein GsGF14o in drought stress responses, we further investigated the expression characteristics of GsGF14o in detail, and demonstrated its positive roles in ABA sensitivity. Quantitative real-time PCR analyses in Glycine soja seedlings and GUS activity assays in PGsGF14O:GUS transgenic Arabidopsis showed that GsGF14o expression was moderately and rapidly induced by ABA treatment. As expected, GsGF14o overexpression in Arabidopsis augmented the ABA inhibition of seed germination and seedling growth, promoted the ABA induced stomata closure, and up-regulated the expression levels of ABA induced genes. Moreover, through yeast two hybrid analyses, we further demonstrated that GsGF14o physically interacted with the AREB/ABF transcription factors in yeast cells. Taken together, results presented in this study strongly suggested that GsGF14o played an important role in regulation of ABA sensitivity in Arabidopsis.

Calcium, as the most widely accepted messenger, plays an important role in plant stress responses through calcium-dependent signaling pathways. The calmodulin-like family genes (CMLs) encode Ca2+ sensors and function in signaling transduction in response to environmental stimuli. However, until now, the function of plant CML proteins, especially soybean CMLs, is largely unknown. Here, we isolated a Glycine soja CML protein GsCML27, with four conserved EF-hands domains, and identified it as a calcium-binding protein through far-UV CD spectroscopy. We further found that expression of GsCML27 was induced by bicarbonate, salt and osmotic stresses. Interestingly, ectopic expression of GsCML27 in Arabidopsis enhanced plant tolerance to bicarbonate stress, but decreased the salt and osmotic tolerance during the seed germination and early growth stages. Furthermore, we found that ectopic expression of GsCML27 decreases salt tolerance through modifying both the cellular ionic (Na+, K+) content and the osmotic stress regulation. GsCML27 ectopic expression also decreased the expression levels of osmotic stress-responsive genes. Moreover, we also showed that GsCML27 localized in the whole cell, including cytoplasm, plasma membrane and nucleus in Arabidopsis protoplasts and onion epidermal cells, and displayed high expression in roots and embryos. Together, these data present evidence that GsCML27 as a Ca2+-binding EF-hand protein plays a role in plant responses to bicarbonate, salt and osmotic stresses.

The PHD-finger family has been demonstrated to be involved in regulating plant growth and development. However, little information is given for its role in environmental stress responses. Here, we identified a total of 59 PHD family genes in the rice genome. These OsPHDs genes were located on eleven chromosomes and synteny analysis only revealed nine duplicated pairs within the rice PHD family. Phylogenetic analysis of all OsPHDs and PHDs from other species revealed that they could be grouped into two major clusters. Furthermore, OsPHDs were clustered into eight groups and members from different groups displayed a great divergence in terms of gene structure, functional domains and conserved motifs. We also found that with the exception of OsPHD6, all OsPHDs were expressed in at least one of the ten tested tissues and OsPHDs from certain groups were expressed in specific tissues. Moreover, our results also uncovered differential responses of OsPHDs expression to environmental stresses, including ABA (abscisic acid), water deficit, cold and high Cd. By using quantitative real-time PCR, we further confirmed the differential expression of OsPHDs under these stresses. OsPHD1/7/8/13/33 were differentially expressed under water deficit and Cd stresses, while OsPHD5/17 showed altered expression under water deficit and cold stresses. Moreover, OsPHD3/44/28 displayed differential expression under ABA and Cd stresses. In conclusion, our results provide valuable information on the rice PHD family in plant responses to environmental stress, which will be helpful for further characterizing their biological roles in responding to environmental stresses.

So far, it has been suggested that phosphoenolpyruvate carboxylases (PEPCs) and PEPC kinases (PPCKs) fulfill several important non-photosynthetic functions. However, the biological functions of soybean PPCKs, especially in alkali stress response, are not yet well known. In previous studies, we constructed a Glycine soja transcriptional profile, and identified three PPCK genes (GsPPCK1, GsPPCK2 and GsPPCK3) as potential alkali stress responsive genes. In this study, we confirmed the induced expression of GsPPCK3 under alkali stress and investigated its tissue expression specificity by using quantitative real-time PCR analysis. Then we ectopically expressed GsPPCK3 in Medicago sativa and found that GsPPCK3 overexpression improved plant alkali tolerance, as evidenced by lower levels of relative ion leakage and MDA content and higher levels of chlorophyll content and root activity. In this respect, we further co-transformed the GsPPCK3 and SCMRP genes into alfalfa, and demonstrated the increased alkali tolerance of GsPPCK3-SCMRP transgenic lines. Further investigation revealed that GsPPCK3-SCMRP co-overexpression promoted the PEPC activity, net photosynthetic rate and citric acid content of transgenic alfalfa under alkali stress. Moreover, we also observed the up-regulated expression of PEPC, CS (citrate synthase), H(+)-ATPase and NADP-ME genes in GsPPCK3-SCMRP transgenic alfalfa under alkali stress. As expected, we demonstrated that GsPPCK3-SCMRP transgenic lines displayed higher methionine content than wild type alfalfa. Taken together, results presented in this study supported the positive role of GsPPCK3 in plant response to alkali stress, and provided an effective way to simultaneously improve plant alkaline tolerance and methionine content, at least in legume crops.

The TIFY family is a novel plant-specific protein family, and is characterized by a conserved TIFY motif (TIFF/YXG). Our previous studies indicated the potential roles of TIFY10/11 proteins in plant responses to alkaline stress. In the current study, we focused on the regulatory roles and possible physiological and molecular basis of the TIFY10 proteins in plant responses to alkaline stress. We demonstrated the positive function of TIFY10s in alkaline responses by using the AtTIFY10a and AtTIFY10b knockout Arabidopsis, as evidenced by the relatively lower germination rates of attify10a and attify10b mutant seeds under alkaline stress. We also revealed that ectopic expression of GsTIFY10a in Medicago sativa promoted plant growth, and increased the NADP-ME activity, citric acid content and free proline content but decreased the MDA content of transgenic plants under alkaline stress. Furthermore, expression levels of the stress responsive genes including NADP-ME, CS, H+-ppase and P5CS were also up-regulated in GsTIFY10a transgenic plants under alkaline stress. Interestingly, GsTIFY10a overexpression increased the jasmonate content of the transgenic alfalfa. In addition, we showed that neither GsTIFY10a nor GsTIFY10e exhibited transcriptional activity in yeast cells. However, through Y2H and BiFc assays, we demonstrated that GsTIFY10a, not GsTIFY10e, could form homodimers in yeast cells and in living plant cells. As expected, we also demonstrated that GsTIFY10a and GsTIFY10e could heterodimerize with each other in both yeast and plant cells. Taken together, our results provided direct evidence supporting the positive regulatory roles of the TIFY10 proteins in plant responses to alkaline stress.

Flowering is a critical event in the life cycle of plants; the WRKY-type transcription factors are reported to be involved in many developmental processes sunch as trichome development and epicuticular wax loading, but whether they are involved in flowering time regulation is still unknown. Within this study, we provide clear evidence that GsWRKY20, a member of WRKY gene family from wild soybean, is involved in controlling plant flowering time. Expression of GsWRKY20 was abundant in the shoot tips and inflorescence meristems of wild soybean. Phenotypic analysis showed that GsWRKY20 over-expression lines flowered earlier than the wild-type plants under all conditions: long-day and short-day photoperiods, vernalization, or exogenous GA3 application, indicating that GsWRKY20 may mainly be involved in an autonomous flowering pathway. Further analyses by qRT-PCR and microarray suggests that GsWRKY20 accelerating plant flowering might primarily be through the regulation of flowering-related genes (i.e., FLC, FT, SOC1 and CO) and floral meristem identity genes (i.e., AP1, SEP3, AP3, PI and AG). Our results provide the evidence demonstrating the effectiveness of manipulating GsWRKY20 for altering plant flowering time.

Plant Snf1 (sucrose non-fermenting-1) related protein kinase (SnRK), a subfamily of serine/threonine kinases, has been implicated as a crucial upstream regulator of ABA and osmotic signaling as in many other signaling cascades. In this paper, we have isolated a novel plant specific ABA activated calcium independent protein kinase (GsAPK) from a highly salt tolerant plant, Glycine soja (50109), which is a member of the SnRK2 family. Subcellular localization studies using GFP fusion protein indicated that GsAPK is localized in the plasma membrane. We found that autophosphorylation and Myelin Basis Protein phosphorylation activity of GsAPK is only activated by ABA and the kinase activity also was observed when calcium was replaced by EGTA, suggesting its independence of calcium in enzyme activity. We also found that cold, salinity, drought, and ABA stress alter GsAPK gene transcripts and heterogonous overexpression of GsAPK in Arabidopsis alters plant tolerance to high salinity and ABA stress. In summary, we demonstrated that GsAPK is a Glycine soja ABA activated calcium independent SnRK-type kinase presumably involved in ABA mediated stress signal transduction.