A bstract: By combining the effective Lagrangian and Bethe-Salpeter framework, we studied the mass spectra, wave functions, and strong decay widths of the two pentaquark states $${P}_{\psi }^{N}{\left({444}0\right)}^{+}$$ and $${P}_{\psi }^{N}{\left({4457}\right)}^{+}$$ reported by LHCb in 2019. Taking into account both the mass ordering and the decay widths, our results favor the interpretation of $${P}_{\psi }^{N}{\left({444}0\right)}^{+}$$ and $${P}_{\psi }^{N}{\left({4457}\right)}^{+}$$ as the isospin- $$\frac{1}{2}$$ $$\left[{\overline{D} }^{*}{\Sigma}_{c}\right]$$ molecular states with J ^P configuration $${\left(\frac{3}{2}\right)}^{-}$$ and $${\left(\frac{1}{2}\right)}^{-}$$ , respectively. We first calculate the one-boson-exchange interaction kernel of $$\left[{\overline{D} }^{*}{\Sigma}_{c}\right]$$ in the isospin- $$\frac{1}{2}$$ configuration. Then we present the Bethe-Salpeter equation (BSE) and wave functions for the bound states of a vector meson and a $$\frac{1}{2}$$ baryon with $${J}^{P}=\frac{1}{2}^{-}$$ and $$\frac{3}{2}^{-}$$ . The obtained mass results for the $${\left(\frac{3}{2}\right)}^{-}$$ and $${\left(\frac{1}{2}\right)}^{-}$$ are 4.442 and 4.457 GeV, respectively. Combining the effective Lagrangians and the BS wave functions, we further calculate the strong decay channels $${\overline{D} }^{(*)0}{\Lambda}_{c}^{+}$$ , J / ψ ( η _c ) p , and $$\overline{D}{\Sigma }_{c}^{(*)}$$ for the two $${P}_{\psi }^{N}$$ states. In the favored $$\frac{3}{2}^{-}$$ and $$\frac{1}{2}^{-}$$ configuration, the obtained total widths are 21.8 MeV and 13.0 MeV, respectively, which are substantially consistent with the LHCb data. Our results suggest that $${\overline{D} }^{0}{\Lambda}_{c}^{+}$$ and $${\overline{D} }^{(*)0}{\Lambda}_{c}^{+}$$ are the dominant decay channels to detect $${P}_{\psi }^{N}{\left({444}0\right)}^{+}$$ and $${P}_{\psi }^{N}{\left({4457}\right)}^{+}$$ , respectively.

Lithofacies characterization of organic-rich shales constitutes the essential foundation for sweet spot evaluation in lacustrine shale oil systems. This study targets the first member of the Upper Cretaceous Qingshankou Formation (K₂qn¹) in the southern Songliao Basin. Based on systematic core description of 908 m of core from eight cored wells, combined with 123 total organic carbon (TOC) measurements, 47 whole-rock X-ray diffraction (XRD) analyses, 29 major- and trace-element analyses, and six maceral identification datasets (≥500 organic particles counted per sample), together with conventional well log data from 75 wells (measured vitrinite reflectance $R_o$ = 0.34%–1.38%, mean = 0.94%), we establish an integrated lithofacies classification scheme incorporating the TOC as a classification parameter and develop a log-based lithofacies identification workflow. Eight lithofacies are recognized within K₂qn¹ across the study area, of which three are organic-rich. The high-TOC clay-rich mudstone-grade laminated shale deposited in a deep lake setting (LF-A; mean TOC = 3.18%, clay minerals ≥50%, formed under saline and strongly anoxic-euxinic conditions; mean paleosalinity = 8.06‰, V/(V + Ni) = 0.75–0.97) and the high-to-moderate-TOC felsic mudstone-grade laminated shale deposited in a semi-deep lake setting (LF-B; mean TOC = 2.18%, felsic minerals ≥50%, formed under brackish-to-saline anoxic conditions; mean paleosalinity = 5.10‰, V/(V + Ni) = 0.70–0.84) constitute the dominant organic-rich lithofacies. From Y1 to Y3, the cumulative thickness of organic-rich lithofacies expands from approximately 10 m to approximately 25 m. Areally, the mean TOC increases systematically from 1.65% in the southern delta-front zone to 2.74% in the northern deep lake center, reflecting an enrichment pattern governed primarily by paleoproductivity and modulated jointly by preservation conditions and terrigenous dilution. The log-based identification workflow, established by integrating a modified ΔlogR method with multiple linear regression, achieves a TOC prediction coefficient of determination of $R^2=0.86$ in the calibration well and lithofacies identification accuracies ranging from 64.6% to 94.0% in validation wells, with the highest performance observed in the delta-front facies zone. These results provide quantitative constraints for the genetic interpretation and log-based identification of organic-rich lacustrine shales.

Medium-deep geothermal energy is a key renewable source, but existing coaxial downhole heat exchanger (DHE) systems suffer from low efficiency and temperature decay. This study evaluates the impacts of circulating flow rate, inlet temperature, and operation mode on DHE performance, using field data from two geothermal wells (Well A: 3200m, 130.5$^{\circ}$C; Well B: 2500m, 103.3$^{\circ}$C). Results show that under an optimal condition (LC3: 50 m$^3$/h, 30$^{\circ}$C), Well A's heat extraction rate increased from 35% to 42%, with its outlet temperature rising from 15$^{\circ}$C to 20$^{\circ}$C. In contrast, Well B's rate decreased from 15% to 5%. After one week of continuous operation, the outlet temperature of Well A dropped from 55.7$^{\circ}$C to 16.5$^{\circ}$C, and Well B's from 68$^{\circ}$C to 17$^{\circ}$C. Adopting an intermittent mode (16h operation, 8h shutdown daily) reduced the temperature decay rate by approximately 10%. Based on these findings, we propose optimization strategies: controlling flow rate to 35m$^3$/h, maintaining an inlet temperature of 6--10$^{\circ}$C, and implementing intermittent scheduling. This work provides guidance for the efficient design and sustainable operation of DHE systems.