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Studies on the formation and evolution of the solid electrolyte interface (SEI) film under different ambient temperatures are important to understand the failure behavior of lithium-ion batteries (LIBs). Herein, in-situ electrochemical impedance spectroscopy (EIS) test is performed on the whole discharge process of Si@Graphite@C/Li cell at 0, 25 and 55 ℃, respectively. Combining with scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy characterizations, it is found that the SEI film undergoes a complicated evolution process of pre-formation, self-improvement and gradual decay in succession at 25 ℃. Besides, due to the dissolution of organo-alkyl lithium at high temperature, the formed film is mainly composed of LiF, Li2CO3 and other inorganic salts, which helps to decrease the impedance. However, the electrolyte is consumed continuously on the new exposed interface, leading to the degraded performance of the cell. Moreover, the dynamic properties of Li+ ions are poor at low temperature, though the migration ability of Li+ ions in the solid phase can be improved as the cycle goes on. Therefore, the development and application of in-situ EIS technology are expected to become an important means to explain the electrochemical performance of batteries.

The heavy oil reservoir is a special kind of oil and gas reservoir that differs from the conventional reservoir in many ways. Due to the high viscosity of crude oil, it is not easy to recover. When the viscosity of underground crude oil exceeds 150 cp, the land heavy oil field is generally developed by thermal recovery. S.Z. oilfield is a heavy oil reservoir in the Bohai Sea, with surface crude oil viscosity of 3000–25,000 cp and underground crude oil viscosity of 400–1000 cp. Limited by offshore equipment, the development strategy of land oilfields can't be directly applied. High production capacity is obtained through the cold production development of horizontal branch experimental wells, and the water drive production capacity can reach 40–70 m3/day. At present, there is a lack of research on cold recovery development under the viscosity of crude oil. The existing primary research and common knowledge are challenging to support efficient development technology for effectively producing heavy oil reservoirs. In this paper, through physical simulation experiments, the phase behavior and rheological properties of crude oil in the target block are studied, and the rheological properties of crude oil are clarified. Then, the depletion production and water flooding experiments are carried out, and the displacement characteristics and laws of water flooding cold production are analyzed. Finally, the indoor experiments of water flooding sweep efficiency and oil displacement efficiency in the target block are carried out. Clear its micro and macro spread. It provides technical support for the effective production of offshore heavy oil fields.

X oilfield is a typical sandstone reservoir with big bottom water in the Bohai Sea. The viscosity of crude oil ranges from 30 to 425 cp. Single sand development with the horizontal well is adopted. At present, the water content is as high as 96%. The water cut of the production well is stable for a long time in the high water cut period. The recoverable reserves calculated by conventional methods have gradually increased, and even the partial recovery has exceeded the predicted recovery rate. This study carried out an oil displacement efficiency experiment under big water drive multiple to accurately understand an extensive bottom water reservoir's production law in an ultra-high water cut stage. It comprehensively used the scanning electron microscope date, casting thin section, oil displacement experiment, and production performance to analyze the change law of physical properties and relative permeability curve from the aspects of reservoir clay minerals, median particle size, pore distribution, and pore throat characteristics. Therefore, the development law of horizontal production wells in sandstone reservoirs with big bottom water is understood. It evaluates the ultimate recovery of sandstone reservoirs with big bottom water. It provides a fundamental theoretical basis and guidance for dynamic prediction and delicate potential tapping of sandstone reservoirs with big bottom water at a high water cut stage.

Silicon-based anode material is one of the most promising alternative anodes for graphite due to its advantages of abundant reserves, environmental protection and high-energy-density. However, silicon still cannot be directly applied commercially as anode materials owing to the existences of huge volume change during the alloying and dealloying process. Herein, porous Si@C composites are prepared by employment of nano silicon as the active substance particles, lithium chloride as the template and pitch powder as the carbon precursor. Results of electrochemical performance tests show that the cell based on the in-situ prepared porous Si@C composites deliver a reversible good cycle stability. Besides, porous Si@C composites show a lower thickness expansion rate of electrode (15.38%), compared with pure nano silicon (162.46%) and conventional Si@C anodes (40.24%), respectively. It is believed that the improved performance is benefitted from the porous structure, which provides a buffer for the expansion of silicon, reduces the volume expansion of the electrode during the charge and discharge process, and thus inhibits the damage to the solid electrolyte interphase film outside the Si@C composites. This work provides an environmentally friendly method to prepare porous Si@C composite anode materials, which is suitable for large-scale preparation and industrialized production.

Additional file 1: Table S1. Primer sequences used in lentivirus overexpression. Table S2. siRNA target sequences used for gene expression interference. Table S3. Primer sequences used for PCR amplification. Table S4. Predicted CBSs on the YAP promoter.

Background and Purpose: Small vessel disease (SVD) imaging markers are related to ischemic and hemorrhage stroke and to cognitive dysfunction. This study aimed to clarify the relationship between SVD imaging markers and subcortical vascular dementia in severe SVD burden.Methods: A total of 57 subjects with multiple lobar cerebral microbleeds (CMBs) and four established SVD imaging markers were enrolled from the dementia and stroke registries of a single center. Visual rating scales that are used to semi-quantify SVD imaging changes were analyzed individually and compositely to make correlations with cognitive domains and subcortical vascular dementia.Results: Dementia group had higher subcortical and total white matter hyperintensities (WMHs) and SVD composite scores than non-dementia group. Individual imaging markers correlated differently with one another and had distinct cognitive correlations. After adjusting for demographic factors, multivariate logistic regression indicated associations of subcortical WMHs (odds ratio [OR] 2.03, CI 1.24–3.32), total WMHs (OR 1.43, CI 1.09–1.89), lacunes (OR 1.18, CI 1.02–1.35), cerebral amyloid angiopathy-SVD scores (OR 2.33, CI 1.01–5.40), C1 scores (imaging composite scores of CMB and WMH) (OR 1.41, CI 1.09–1.83), and C2 scores (imaging composite scores of CMB, WMH, perivascular space, and lacune) (OR 1.38, CI 1.08–1.76) with dementia.Conclusions: SVD imaging markers might have differing associations with cognitive domains and dementia. They may provide valuable complementary information in support of personalized treatment planning against cognitive impairment, particularly in patients with a heavy SVD load.