•A plasmonic perfect absorber (PA) was proposed to serve as a refractive index sensor.•The PA with a high quality-factor of 41.2 and an absorbance of 99.9% at 142.6THz.•Physics origin of PA is ...studied by field, current distribution and LC circuit model.•The PA for refractive index sensor yields a sensitivity of 1445nm/RIU.
We present a non-planar all-metal plasmonic perfect absorber (PA) with response polarization independent in infrared region, which can be served as a sensor for enhanced refractive index sensing. Distinct from previous designs, the proposed PA consisted of all metal structured film constructed with an assembly of four-tined rod resonators (FRRs). The PA with a high quality-factor (Q-factor) of 41.2 and an absorbance of 99.9% at 142.6THz has been demonstrated numerically. The resonance behavior occurs in the space between the rods of the FRRs, which is remarkable different conventional sandwiched structural PAs. Based on equivalent LC circuit theory, the absorption peak can be finely tuned by varying the geometrical dimensions of the FRRs. Furthermore, the resonance frequency shows highly sensitive response to the change of refractive index in the surrounding medium. A careful design for refractive index sensor can yield a sensitivity of 1445nm/refractive index unit (RIU) and a figure of merit (FOM) of 28.8. The demonstrated design of the plasmonic PA for sensing provides great potential application in enhancing refractive index sensors and the enhanced infrared spectroscopy.
A new quinoline-based chemosensor (CQ) for sequential detection of Cu2+ and CN− has been synthesized, where diaminomaleonitrile is introduced as recognition group. After addition of Cu2+, sensor CQ ...in aqueous solution (DMSO/H2O) displays remarkable colorimetric change from the light yellow to red, which is attributed to the extended intermolecular charge transfer in CQ-Cu2+complex. Sensor CQ shows a highly selective and sensitive response to Cu2+, which can be used as Test strips to conveniently monitor Cu2+. In addition, CQ-Cu2+complex could be applied to monitor sequentially cyanide anion with dramatic colour change based on copper ion complex displacement mechanism.
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•We report a new quinoline-based colorimetric chemosensor CQ for Cu2+ with high selectivity and sensitivity.•Test strips immersed sensor CQ can be used to conveniently monitor Cu2+ by naked-eyes.•Sensor CQ treated with Cu2+ can be applied to sequentialy detect cyanide anion.
A continuously cored well covering the Carboniferous-Permian Benxi, Taiyuan, and Shanxi formations in the eastern Ordos Basin provides a rare window into environmental conditions of the ...marine-continental transitional strata. Integration of petrographic, mineralogical, and high-resolution geochemical data allows marine-continental investigating the depositional environment, organic abundance, detrital influx, paleoclimate, paleo-water salinity, and paleoredox conditions of transitional facies. The marine-continental transitional strata in the Upper Carboniferous to Lower Permian consist of complex interbedding of sandstone, shale, coal and limestone. TOC contents display a considerable change in the vertical direction, with high TOC content in coal, moderate TOC in shale, low TOC content in limestone and no noticeable TOC enrichment in sandstone. The Upper Carboniferous Benxi Formation is dominated by marine facies then changing into transitional facies. The Lower Permian Taiyuan Formation is characterized by multiple alternation of marine and transitional facies. Marine limestones are characterized by low detrital influx proxies, whereas transitional shales show high detrital influx input and oxic environment. The Lower Permian Shanxi Formation is a typical marine-continental transitional depositional system, which is characterized by complex interbedding of shales, sandstones and coals. Sandy intervals were deposited in deltaic and tidal flat environment and characterized by high Ti and Al content, low TOC (0.09–0.97%, avg. 0.31%), relatively low U/Th (0.11–0.32, avg. 0.17), showing limited influence of seawater. Shale intervals were deposited in a lagoonal environment with high TOC (0.94–40.64%, avg. 5.43%), Sr/Ba and trace elemental proxies values (U/Th, 0.18–3.27%, avg. 0.44%; MoEF, 0.95–32.3, avg. 8.56; UEF, 0.67–15.17, avg. 2.53). This study shows that high-resolution geochemical characteristics of elements could be reliable indicators for sedimentary facies analysis, and hence could provide broader implications for utilizing trace element geochemistry from marine-continental transitional periods in which sedimentary environment changes frequently and organic-rich sediment accumulated under varied conditions.
•A systematic sedimentological study was conducted on C-P transitional shales.•We establish a high-resolution paleoenvironmental profile of transitional strata.•Depositional models were established for of the C-P transitional facies.•Geochemical characteristics of elements useful for sedimentary facies analysis
To study organic matter and pore characteristics of the Lower Cambrian Niutitang organic-rich shales, 166 shale samples from the Niutitang Formation were collected from the studied well, drilled in ...Kaiyang county in the Northern Guizhou area, Upper Yangtze region. All of the 166 shale cores were analysed for total organic carbon (TOC), total sulfur (TS), and the stable carbon isotope of kerogen (δ13Corg). Shale samples with varying TOC values were chosen for mineral composition analysis, helium porosity measurement and low pressure nitrogen adsorption measurement. The Lower Cambrian Niutitang Formation features high organic matter content, type I oil-prone organic matter, ultra-thick organic-rich shales, and an abundance of brittle minerals exhibiting favourable characteristics for the Lower Cambrian shale gas exploration in the Upper Yangtze region. Helium porosity measurement and low pressure nitrogen adsorption measurements were performed on selected shale samples with varying TOC content in order to analyse and characterize pore characteristics. Significant differences in mineral composition and pore characteristics were found between clay-rich and clay-poor Niutitang shales. Quartz weakly correlated with TOC content in clay-rich shales, which contained minor biogenically contributed quartz and performed better in terms of reservoir properties than clay-poor shales, and exhibited higher porosity, maximum nitrogen quantity adsorbed, pore volume, and specific surface area. In clay-rich shales, the maximum nitrogen quantity adsorbed, total pore volume, and specific surface area positively correlated with TOC content (R2=0.77, 0.79, and 0.75, respectively). The pore volume of clay-rich shales was dominated by mesopores, and both micropore and mesopore volume of clay-rich shales correlated significantly with TOC content. In clay-poor shales, quartz positively correlated with TOC content, indicating biogenic contribution to quartz. Micropore volume and mesopore volume of clay-poor shales were weakly positively correlated with TOC content. Pore volume, especially mesopore volume, may be affected by the recrystallization of biogenic silica, exhibiting identical micropore volume with clay-rich shales but lower mesopore volume.
•The Lower Cambrian shales displayed high-quality organic matter concentrations.•The quartz content positively correlated with TOC content in the clay-poor shales.•Organic matter plays a positive role in the pore structure of Niutitang shales.•Significant differences exist in the pore characteristics of clay-rich and clay-poor shales.
Semi-confined pyrolysis experiments were performed on core and powdered samples taken from type-II lacustrine mudstone to investigate the effects of sample rock fabrics on hydrocarbon generation and ...porosity changes when shale is subjected to pyrolysis. The generated hydrocarbons were analysed by organic geochemical methods to reflect differences in constituents and carbon isotopes. Gas (N2 and CO2) adsorption tests were applied to solid residues to characterize the formation and development of pores after the two series of pyrolysis experiments. Simple calculations indicate that hydrocarbons prefer to expulse as intact rock fabric is destroyed. Secondary cracking gas accounted for approximately 23–30% and 28–49% of all gaseous hydrocarbons in the powdered and core samples, respectively. Side reactions, such as mineral catalytic and recombination reactions, prevailed during the semi-closed pyrolysis of powdered sample at 300–500 °C, causing generated C3+ hydrocarbon yields to be lower than those of the core sample. Additionally, gaseous hydrocarbons generated from the powdered sample were characterized by more positive δ13C and higher iso-/n-C4,5 and C1/C1-5 values. Side reactions ceased at 500–550 °C, and corresponding ratios tended to equalize. For the powdered samples, a higher expulsive ratio of hydrocarbons led to better pore development, the mesopore volume increased with increasing temperatures, and micropore volume decreased above 450 °C. Comparatively, the mesopore volume decreased above 450 °C for the core sample, and the micropore volume decreased above 500 °C. These results are helpful for revealing the genetic characteristics of shale gas and for understanding the origins of organic-hosted pores of the Cambrian Niutitang shale in southern China. The study suggests that samples with intact rock fabric should be used in future laboratory pyrolysis tests to generate results that better reflect natural conditions.
•Semi-closed pyrolysis results for core and powdered samples of a same mudstone were compared.•The expulsion-retention mechanisms of hydrocarbons are affected by rock fabrics.•Rock fabrics have important effects on porosity development of samples.•Samples with intact rock fabrics should be used for future laboratory pyrolysis.
Closed and semi-closed pyrolysis of a lacustrine shale sample was conducted using the same instrument characterized by lithostatic pressure and limited reactive space in order to unravel the impacts ...of the system sealing capacity on organic matter occurrence and nanopore development in shales under conditions analogous to natural processes. The solid residues were subjected to organic geochemical measurements, low-pressure gas (N2 and CO2) adsorption tests, and field emission-scatter electrical microscope analysis. The results revealed that solvent extraction played positive and negative roles in the pore development of solid residues from both systems at different thermal maturities. Inorganic and organic pores were primarily filled or shielded by soluble bitumen at low and high temperatures, respectively. The occurrences of organic matter in solid residues from the two systems were different at lower temperatures but gradually evolved similarly at higher temperatures and were dominated by nanoscale interparticle organic matter. Organic pore occurrence in solid residues from the two systems was approximately comparable. However, differences in pore volume and specific surface area of solid residues from the closed and semi-closed systems increased measurably below 550 °C. At 550 °C, a strong mechanical compaction and overpressure environment caused deformation and closure of pores surrounding rigid minerals and pores associated with ductile minerals surrounding organic matter in solid residue from the closed system, while only a few pores surrounding rigid minerals from the semi-closed system deformed. Consequently, similar pore parameters of solid residues from the two systems were obtained at this temperature. Additionally, the variation in organic porosity of solid residues from the two systems has obvious stages based on mass balance calculation. The organic porosity evolution is collectively affected by system sealing capacity and thermal maturity at lower matured stages. In contrast, organic porosity evolution in solid residues is independent of system sealing capacity at high- and overmatured stages. Although the depositional environment is different, this study provides direct evidence that the difference in system sealing capacity is not the predominant factor leading to different organic pore developments in the Silurian and Cambrian shales in South China.
•Closed and semi-closed pyrolysis were conducted under conditions analogous to geology.•Pore development in solid residues before and after solvent extraction were compared.•Pore developments in solid residues were affected by system sealing capacity as temperatures < 550 °C.•The system sealing capacity and thermal maturity controlled the evolution of organic porosity at different stages.
Abstract Controlling microrobot locomotion in vessels and capillaries is crucial for precise drug delivery and minimally invasive surgeries. However, this is challenging due to the complex ...interactions with red blood cells (RBCs) and the difficulty navigating within the dense environment. Here, we construct a numerical framework to evaluate the relative resistance coefficient ( $${C}_{{{\rm{r}}}^{* }$$ C r * ) of a microrobot propelled through RBC suspensions. Our experiments validate the numerical results. We find that $${C}_{{{\rm{r}}}^{* }$$ C r * increases for smaller microrobots and higher hematocrit levels, while magnetic force strength weakly impacts $${C}_{{{\rm{r}}}^{* }$$ C r * . $${C}_{{{\rm{r}}}^{* }$$ C r * is smaller than the resistance coefficient of a macroscale robot estimated from the apparent viscosity of the RBC suspension. The aspect ratio of a prolate ellipsoidal microrobot influences $${C}_{{{\rm{r}}}^{* }$$ C r * along its long-axis direction. Additionally, machine learning accurately predicts $${C}_{{{\rm{r}}}^{* }$$ C r * . These insights could enhance the design and control of microrobots for medical applications.
Closed and semi-closed pyrolysis of a lacustrine shale sample were conducted using the same instrument characterized by lithostatic pressure and limited reactive space in order to unravel the impacts ...of system sealing capacity on organic matter evolution and hydrocarbon generation in shales under conditions analogous to natural processes. The products and solid residues were subjected to chemical composition determination, gaseous carbon isotopic composition analysis, solvent extraction, and Rock-Eval pyrolysis. Higher organic matter transformation and oil retention contents were obtained at 300–500 °C in the closed pyrolysis system compared to those in the semi-closed system at the same temperature ranges. However, lower yields of hydrocarbons except for methane were obtained in the closed system at this temperature range, while the iso-/n-C4,5 as well as C1/C1-5 values were significantly higher in this system. Stronger recombined reactions between kerogen and hydrocarbons were proposed to occur at 300–500 °C during the closed pyrolysis process, leading to the consumption of oil and hydrocarbon gases. Ultimately, positive deviations of initially more negative δ13C2∼3 values were occurred in the closed system, resulting in similar δ13C2∼3 values from the two systems before secondary cracking of hydrocarbon gases commences, but the δ13C1 value from the closed system was overall more negative. Different water retention ratios and hydrocarbon expulsion efficiencies induced by system sealing capacity are the predominant factor controlling organic matter evolution and petroleum generation during the pyrolysis processes. This highlights that the different gas contents of the Cambrian and Silurian shales in South China may be associated with the differences in the system sealing capacities of shales, although the sedimentary environment of the studied sample is lacustrine, and the lower methane content of the Cambrian shale gas is probably ascribed to semi-closed system. Finally, a higher ratio of oil cracking gas may be an important signal for natural gas systems that have better exploration potential.
•Closed and semi-closed pyrolysis were conducted under conditions analogous to geology.•Organic matter transformation and petroleum generation were different in the two systems.•Ratio of oil cracking gas was associated with potential and prospect of natural gas exploration.
To study the sedimentary environment of the Lower Cambrian organic-rich shales and isotopic geochemical characteristics of the residual shale gas, 20 black shale samples from the Niutitang Formation ...were collected from the Youyang section, located in southeastern Chongqing, China. A combination of geochemical, mineralogical, and trace element studies has been performed on the shale samples from the Lower Cambrian Niutitang Formation, and the results were used to determine the paleoceanic sedimentary environment of this organic-rich shale. The relationships between total organic carbon (TOC) and total sulfur (TS) content, carbon isotope value (δ13Corg), trace element enrichment, and mineral composition suggest that the high-TOC Niutitang shale was deposited in an anoxic environment and that the organic matter was well preserved after burial. Stable carbon isotopes and biomarkers both indicate that the organic matter in the Niutitang black shales was mainly derived from both lower aquatic organisms and algaes and belong to type I kerogen. The oil-prone Niutitang black shales have limited residual hydrocarbons, with low values of S2, IH, and bitumen A. The carbon isotopic distribution of the residual gas indicate that the shale gas stored in the Niutitang black shale was mostly generated from the cracking of residual bitumen and wet gas during a stage of significantly high maturity. One of the more significant observations in this work involves the carbon isotope compositions of the residual gas (C1, C2, and C3) released by rock crushing. A conventional δ13C1–δ13C2 trend was observed, and most δ13C2 values of the residual gases are heavier than those of the organic matter (OM) in the corresponding samples, indicating the splitting of ethane bonds and the release of smaller molecules, leading to 13C enrichment in the residual ethane.
•Niutitang black shales was mainly derived from both lower aquatic organisms and algaes and belong to type I kerogen.•Organic rich Niutitang shale was deposited in an anoxic environment.•Oil-prone Niutitang shale with high TOC abundance but very low residual hydrocarbon.•The retained gas show a conventional δ13C1–δ13C2 trend and most δ13C2 values are heavier than those of organic matter (OM).
Abstract
Graph learning models have received increasing attention in the computational analysis of single-cell RNA sequencing (scRNA-seq) data. Compared with conventional deep neural networks, graph ...neural networks and language models have exhibited superior performance by extracting graph-structured data from raw gene count matrices. Established deep neural network-based clustering approaches generally focus on temporal expression patterns while ignoring inherent interactions at gene-level as well as cell-level, which could be regarded as spatial dynamics in single-cell data. Both gene–gene and cell–cell interactions are able to boost the performance of cell type detection, under the framework of multi-view modeling. In this study, spatiotemporal embedding and cell graphs are extracted to capture spatial dynamics at the molecular level. In order to enhance the accuracy of cell type detection, this study proposes the scHybridBERT architecture to conduct multi-view modeling of scRNA-seq data using extracted spatiotemporal patterns. In this scHybridBERT method, graph learning models are employed to deal with cell graphs and the Performer model employs spatiotemporal embeddings. Experimental outcomes about benchmark scRNA-seq datasets indicate that the proposed scHybridBERT method is able to enhance the accuracy of single-cell clustering tasks by integrating spatiotemporal embeddings and cell graphs.
