Search

Short-circuit current calculation is one of the most basic and commonly used calculations in power systems, which is related to the setting of distribution network relay protection, selection of electrical equipment, identification of short-circuit accidents, and so on. This paper establishes the grid structure of grid short-circuit with 220kV substation as the boundary, analyzes the current composition of grid short-circuit, designs the basic method of grid short-circuit current calculation based on the Davignan equivalence model, and calculates its steady-state value. In the calculation of grid short-circuit current parameters, the idea of casting and cutting capacitors is introduced to construct the measurement strategy for short-circuit current capacity parameters. Based on the semi-physical simulation test technology, the semi-physical simulation verification platform of grid short-circuit is established by combining the real-time digital simulation system, and the error between the calculated value of short-circuit current and the simulation measurement value is analyzed by this platform. When the short-circuit capacity parameter is 100MVA, the measurement error is only 1.46% near the extreme load, and the minimum error of short-circuit current and in-ring current obtained by the semi-physical simulation platform can be controlled to 2.45% and 4.11%, respectively, and the range of transient peak coefficient error is in the range of [-1.66%,1.39%]. The application of the semi-physical simulation platform for measuring grid short-circuit parameters has high accuracy and guides optimizing grid configuration.

Background: Recurrent spontaneous abortion (RSA) is a serious and common complication of pregnancy caused by multiple factors. The etiology remains incompletely understood, but immunologic factors play important roles. Here, we aimed to evaluate whether circulating immune cells causally impacted RSA. Methods: In this study, we conducted a comprehensive two‐sample Mendelian randomization (MR) study to determine the causal association between the 731 immunophenotypes of human peripheral blood lymphocytes and the number of spontaneous abortions as well as recurrent miscarriage. Sensitivity analyses were performed to assess and minimize heterogeneity and horizontal pleiotropy. Reverse MR analysis was used to assess reverse causality. Results: After Bonferroni‐correction, eight immunophenotypes were significantly associated with the number of spontaneous abortions: FSC‐A on CD4+ T cell (beta = −0.051, 95% CI = [−0.085, −0.017], P‐value = 0.004), CD8 on HLA DR+ CD8+ T cell (beta = −0.040, 95% CI = [−0.067, −0.014], P‐value = 0.003), HLA DR on CD33dim HLA DR+ CD11b− (beta = −0.021, 95% CI = [−0.036, −0.005], P‐value = 0.010), HLA DR+ T cell Absolute Count (beta = 0.022, 95% CI = [0.006, 0.037], P‐value = 0.008), HLA DR+ T cell % lymphocyte (beta = 0.026, 95% CI = [0.010, 0.041], P‐value = 0.001), HLA DR+ T cell % T cell (beta = 0.023, 95% CI = [0.007, 0.039], P‐value = 0.004), HLA DR+ CD4+ T cell % lymphocyte (beta = 0.034, 95% CI = [0.007, 0.060], P‐value = 0.012), and HLA DR on B cell (beta = 0.012, 95% CI = [0.003, 0.021], P‐value = 0.010). In addition, we identified two immunophenotypes associated with recurrent miscarriage: HLA DR on B cell (OR = 0.854, 95% CI = [0.757, 0.964], P‐value = 0.011), and CD19 on naive‐mature B cell (OR = 4.595, 95% CI = [1.674, 12.617], P‐value = 0.003). There was no evidence of heterogeneity, horizontal pleiotropy and reverse causality. Conclusions: Our study demonstrated a tight link between adaptive immune cells and RSA through genetic means, thus providing potential therapeutic targets or novel diagnostic biomarkers. [ABSTRACT FROM AUTHOR]

Whether the oilfield sewage index can reach the reinjection specification is a crucial issue that is urgently need to be solved in polymer flooding systems. Thus the coagulability and floc morphology development of dual coagulants was systematically studied in different pH oily wastewaters. Acidification improved the deprotonation ability of coagulant. Hydrophobic associative polyaluminum silicate-poly dimethyl diallyl ammonium chloride (PASSC-PD) resolved the problem of excessive acid addition. The dual coagulants prepared not only preserved the high charge density of polyaluminum silicate (PASS) itself but also made it have the hydrophobic association and strong bridging ability. Besides, PASSC-PD was compared with hydrophobic associative polyaluminum silicate (PASS-C), PASS, and poly dimethyl diallyl ammonium chloride (PDMDAAC) pertaining to the polymer flooding oily sewage of Daqing Oilfield. The coagulation result demonstrated that PASSC-PD exhibited more advantageous turbidity and oil removal efficiencies than PASS-C, PASS, and PDMDAAC. The floc morphology result showed that adding dual coagulant made the petal-like floc of oily sewage larger at the pH value of 6. Furthermore relevant results evidenced that the coagulant had more successful fruits of turbidity removal of 96.5% and oil removal of 96.3% under weak acid conditions. These can satisfy the reinjection condition of oily sewage. [ABSTRACT FROM AUTHOR]

Future industrialization of organic photovoltaics (OPVs) requires OPVs' processing to be more energy‐efficient and streamlined. Currently, only MoO3 and PEDOT:PSS are commonly used as the anode interface layer (AIL). The processing of MoO3 typically involves vacuum thermal evaporation with stringent thickness requirements. PEDOT:PSS necessitates separate processing and thermal annealing at temperatures exceeding 100 °C to eliminate moisture. This work utilized 3,4,5‐trichlorobenzoic acid (3CBA) as the AIL material. The distinct advantage of 3CBA over PEDOT:PSS and MoO3 is the in situ self‐assembly of 3CBA eliminates the need for separate solution processing, thermal evaporation, or thermal annealing. Remarkably, OPV devices incorporating PM6, BTP‐eC9, and the 3CBA AIL exhibited a superior efficiency of 18.2% compared to those with PEDOT:PSS (17.7%). By using nonhalogenated solvent, o‐xylene, to meet industrialization requirements, the devices achieved an exceptional efficiency of 18.8%, the highest reported value among devices with in situ self‐assembled interface layers. Furthermore, semi‐transparent devices with 3CBA displayed higher PCE and AVT values (13.1% and 25.7%) than their PEDOT: PSS counterparts, due to the weak absorption of the 3CBA AIL. This work contributes significantly to the high‐throughput production of OPVs by streamlining the AIL processing. [ABSTRACT FROM AUTHOR]