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Background Pancreaticobiliary reflux (PBR) causes chronic inflammation of the gallbladder mucosa and changes in the bile components, which are known to promote gallstone formation. This study aimed to investigate the bile biochemistry changes in gallstone patients with PBR and provide new clues for research on the involvement of PBR in gallstone formation. Methods Patients undergoing surgery for gallstones between December 2020 and May 2021 were eligible for inclusion. The bile biochemistry (including amylase, lipase, triglyceride, cholesterol, free fatty acids [FFAs], alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase [ALP], and γ-glutamyl transferase [γ-GT]) of the included gallstone patients was analysed to determine correlations with PBR. Results In this study, 144 gallstone patients who underwent surgery were enrolled. Overall, 15.97 % of the patients had an increased bile amylase level, which was associated with older age and significantly higher bile levels of ALP, lipase, triglyceride, and FFAs. Positive correlations were observed between amylase and lipase, triglyceride, FFAs levels in the gallbladder bile. However, the bile levels of triglyceride, FFAs, and lipase were positively correlated with each other only in the PBR group and showed no significant correlation in the control (N) group. In addition, elevated bile FFAs levels were found to be an independent risk factor for gallbladder wall thickening. Conclusions In conclusion, PBR-induced increase in FFAs and triglyceride in the gallbladder bile is a cause of gallstone formation, and an increase in bile ALP suggests the presence of cholestasis in PBR.

Background: Neuroimaging studies in Wilson’s disease (WD) have identified various alterations in white matter (WM) microstructural organization. However, it remains unclear whether these alterations are localized to specific regions of fiber tracts, and what diagnostic value they might have. The purpose of this study is to explore the spatial profile of WM abnormalities along defined fiber tracts in WD and its clinical relevance. Methods: Ninety-nine patients with WD (62 men and 37 women) and 91 age- and sex-matched controls (59 men and 32 women) were recruited to take part in experiments of diffusion-weighted imaging with 64 gradient vectors. The data were calculated by FMRIB Software Library (FSL) software and Automated Fiber Quantification (AFQ) software. After registration, patient groups and normal groups were compared by Mann–Whitney U test analysis. Results: Compared with the controls, the patients with WD showed widespread fractional anisotropy reduction and mean diffusivity, radial diffusivity elevation of identified fiber tracts. Significant correlations between diffusion tensor imaging (DTI) parameters and the neurological Unified Wilson’s Disease Rating Scale (UWDRS-N), serum ceruloplasmin, and 24-h urinary copper excretion were found. Conclusions: The present study has provided evidence that the metrics of DTI could be utilized as a potential biomarker of neuropathological symptoms in WD. Damage to the microstructure of callosum forceps and corticospinal tract may be involved in the pathophysiological process of neurological symptoms in WD patients, such as gait and balance disturbances, involuntary movements, dysphagia, and autonomic dysfunction.

Spin polarized scanning tunneling microscopy (SP-STM) and magnetic exchange force microscopy (MExFM) are powerful tools to characterize spin structure at the atomic scale. For low temperature measurements, liquid helium cooling is commonly used, which has the advantage of generating low noise but has the disadvantage of having difficulties in carrying out measurements with long durations at low temperatures and measurements with a wide temperature range. The situation is just reversed for cryogen-free STM, where the mechanical vibration of the refrigerator becomes a major challenge. In this work, we have successfully built a cryogen-free system with both SP-STM and MExFM capabilities, which can be operated under a 9 T magnetic field provided by a cryogen-free superconducting magnet and in a wide temperature range between 1.4 and 300 K. With the help of our specially designed vibration isolation system, the noise is reduced to an extremely low level of 0.7 pm. The Fe/Ir(111) magnetic skyrmion lattice is used to demonstrate the technical novelties of our cryogen-free system.

The effects of Al deoxidation and Zr deoxidation on the microstructure and properties of sulfide stress corrosion resistant high-strength steel have been investigated. The feasibility of the Zr deoxidation instead of Al deoxidation was confirmed by the thermodynamic analysis of the deoxidation of various elements. The experimental results indicate that the average diameters of the inclusions in Al-Steel and Zr-Steel were 2.45 μm and 1.65 μm, respectively. The Al-Steel and Zr-Steel contained 22.38% and 68.77% inclusions per unit area, respectively, and the fraction of inclusions in the Al-Steel and Zr-Steel with diameters less than 2 μm was about 73.46% and 89.63%, respectively, indicating that the Zr deoxidation process could effectively refine inclusions and promote dispersion. The average diameters of austenite grain for the Al-Steel and Zr-Steel were about 9.1 μm and 8 μm, respectively. The fine particles in Zr-Steel could pin the austenite grain boundaries and clearly refine the grains. The average grain size of tempered martensite was 8.2 μm and 3.8 μm, respectively. The yield strength of the Al-Steel and Zr-Steel was 922 MPa and 939 MPa, respectively; the impact energy was 60 ± 6 J and 132 ± 6 J, respectively. Moreover, the fracture time of the NACE-A was from 28 h (Al-Steel) to 720 h (Zr-Steel) without fracture. The experimental steel deoxidized by Zr achieved a simultaneous improvement in strength, toughness and sulfide stress corrosion resistance, and the effect of inclusions on the fracture of the sulfide stress corrosion resistant high-strength steel can be explained by the Griffith theory.

We systematically investigate the plugging performance and oil-displacement efficiency of the novel bilayer-coating microspheres (BCMS) designed for in-depth conformance control within heterogeneous hydrocarbon reservoirs. Visualization experiments on various glass models, as well as one- and two-phase core floods have been carried out at reservoir temperature and fluid salinity. Our results demonstrate that the rigid outer layer of BCMS can successfully protect its adhesive inner coating, enabling BCMS to transport deeply into porous media. Increasing particle concentration yields higher collision probability, leading to the formation of particle assembly that could effectively block pore throats in high-permeability channels and achieve more oil recovery in the low-permeability zones. It is also shown that as the BCMS slug size increases, the oil recovery asymptotically reaches a maximum value. A larger slug size cannot highly enhance the plugging performance yet significantly increase the resistance factor. A smaller permeability ratio of parallel cores leads to a narrower difference between the fractional flow rates. When the permeability ratio is two or lower, the fractional flow rates of parallel cores are both around 50%, yielding the best oil-displacement efficiency. BCMS exhibits promising application potential in production enhancement under reservoir conditions.

A composite manganese-based catalytic ceramic membrane (Mn-CCM) was developed by a solid-state sintering method, and its effectiveness toward activation of peroxymonosulfate (PMS) for the degradation of 11 pharmaceutical and personal care products (PPCPs) mixture was tested. The optimized Mn-CCMs/PMS system showed remarkable degradation efficiencies for PPCPs mixture with total removal90% in ultrapure water, river water and natural organic matter (NOM) solution. The Mn-CCMs/PMS system showed the contribution of different phenomena in PPCPs removal in the order of catalytic oxidation (54.7%, Mn-CCMs/PMS)noncatalytic oxidation (42.3%, PMS oxidation)adsorption (3.0%, by Mn-CCMs). The singlet oxygen (

Background:Cerebrovascular diseases are the leading cause of death in China, and the China is undergoing rapid change.However, trends in cerebrovascular disease mortality remains unclear in urban-rural China.Methods:Mortality of cerebrovascular disease (2005-2019) were collected for quinquennial age group stratified by area(urban/rural) from China Statistical Yearbook.The annual changes(APC) and the average annual percent changes(AAPC) of cerebrovascular disease mortality were analyzed by joinpoint regression analysis;age,period,cohort effects on mortality were estimated by age-period-cohort model.Results:Though 2005-2019,standardized mortality significantly rose in rural areas(AAPC=3.3%,95%CI:1%,5.6%) and moderately increased in urban areas(AAPC=1.5%,95%CI:0.6%,2.4%).The age-period-cohort model indicated that there was an obviously age effect and cohort effect..The trend of age effect showed an increase with advancing age.There is a favourable throughout in cohort effects with significantly decrease of both rural and urban areas in China.Conclusions:Both urban areas and rural areas of China,the trend of cerebrovascular disease mortality substantially increased with advance of age.Cerebrovascular disease mortality trend may continue to rise in China.Respectively intervention should be conducted, especially for rural areas.Moreover,paying attention to the physical and mental health of the elderly is also unavoidable.

The performance of an integrated process comprising coagulation, ozonation, and catalytic ceramic membrane filtration (CMF) followed by treatment with biological active carbon (BAC) was evaluated in a pilot-scale (96 m

The Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province (SYGMP) is an important region for Pb-Zn resources in China. However, considerable controversy remains as to whether the Pb-Zn deposits are Mississippi Valley Type (MVT). The Maozu deposit, a typical example of the carbonate-hosted Pb-Zn deposits in the SYGMP, occurs in the late Ediacaran Dengying Formation and its ore bodies are divided into three types: lower layer (LL), vein layer (VL), and upper layer (UL) ore bodies based on their spatial relationship. In this study, laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) was used to systematically analyze the trace-element compositions of sphalerite and galena in these three ore bodies. The results show that sphalerite is characterized by Cd and Ge enrichment; Fe, Mn, and Co depletion; and local In and Sn enrichment. Most of these elements likely appear as solid solutions in sphalerite and show a wide compositional variation, which is probably related to the medium- and low-temperature mixing of the ore-forming fluids. The local enrichment of In and Sn is likely attributed to the long-distance migration of ore-forming fluids through In-Sn-bearing volcaniclastic rocks. In vs. Sn and (Cu + Sb) vs. (Ag + Ge) show strong correlations and similar element distribution in the mapped images, indicating that these elements may be incorporated into sphalerite via a coupled substitution for Zn as 2In3+ + Sn4+ + 2☐ ↔ 5Zn2+ (☐ = vacancies) and 4(Cu+ + Sb3+) + (Ge4+ + 2Ag+) + 2☐ ↔ 13Zn2+. Galena is enriched in Ag and Sb with minor Cd and Se and depleted in Bi, and most of the elements may occur as solid solutions. Ag vs. Sb in galena displays a strong positive correlation, implying the coupled substitution of Ag+ + Sb3+ ↔ 2Pb2+. Notably, the majority of the trace-element concentrations gradually decrease in the order LL → UL except Fe, Co, Cu, and Ge, while Fe, In, and Sn in sphalerite and Ag and Sb in galena have the highest concentration in the VL, indicating that the VL is a secondary migration channel for the ore-forming fluids. Furthermore, the trace-element compositions of the sulfides in the Maozu Pb-Zn deposit are consistent with the typical MVT deposit (hosted in the carbonate sequence) but are markedly different from sedimentary exhalative (SEDEX), volcanogenic massive sulfide (VMS) and skarn-type deposits. Based on these results, as well as the geological and geochemical characteristics of the deposit, the Maozu Pb-Zn deposit is an MVT deposit.

A novel concept of treating oil reservoirs by nanofluids is being developed to improve oil recovery and reduce the trapped oil in hydrocarbon reservoirs. Nanoparticles show great potential in enhancing oil recovery under ambient conditions. In this paper, the approaches of wettability alteration by using nanofluid, stability of nanofluids, and the most reliable wettability alteration mechanisms associated with variant types of nanoparticles have been reviewed. Moreover, the parameters that have a significant influence on nanofluid flooding have been discussed. Finally, the recent studies of the effect of nanoparticles on wettability alteration have been summarised and analysed. Furthermore, this paper presents possible opportunities and challenges regarding wettability alteration using nanofluids.

Oleic acid-modified titania (OA-TiO2) nanoparticles are synthesized for the application of enhanced oil recovery (EOR) in low-permeability reservoirs. The oleic acid is grafted onto the surface of ...

Fines migration induced by injection of low-salinity water (LSW) into porous media can lead to severe pore plugging and consequent permeability reduction. The deep-bed filtration (DBF) theory is used to model the aforementioned phenomenon, which allows us to predict the effluent concentration history and the distribution profile of entrapped particles. However, the previous models fail to consider the movement of the waterflood front. In this study, we derive a stochastic model for fines migration during LSW flooding, in which the Rankine-Hugoniot condition is used to calculate the concentration of detached particles behind and ahead of the moving water front. A downscaling procedure is developed to determine the evolution of pore-size distribution from the exact solution of a large-scale equation system. To validate the proposed model, the obtained exact solutions are used to treat the laboratory data of LSW flooding in artificial soil-packed columns. The tuning results show that the proposed model yields a considerably higher value of the coefficient of determination, compared with the previous models, indicating that the new model can successfully capture the effect of the moving water front on fines migration and precisely match the effluent history of the detached particles.

Precipitation stable isotopes (2H and 18O) are adequately understood on their climate controls in the Tibetan Plateau, especially the north of Himalayas via about 30 years’ studies. However, knowledge of controls on precipitation stable isotopes in Nepal (the south of Himalayas), is still far from sufficient. This study described the intra-seasonal and annual variations of precipitation stable isotopes at Kathmandu, Nepal from 10 May 2016 to 21 September 2018 and analysed the possible controls on precipitation stable isotopes. The enriched δD and δ18O values were identified during non-monsoon season and depleted values were found during monsoon season, showing remarkable intra-seasonal characteristics of monsoon influence. The local meteoric water line suggested a strong influence of evaporation during rainfall in non-monsoon season and significant impact of non-equilibrium processes on precipitation during monsoon season. Temperature–δ18O exhibited negative correlation for overall samples and showed no significant correlation in seasonal scales, which was attributed to the influence of monsoon moisture. The positive correlation was observed between δ18O and outgoing longwave radiation (OLR) in monsoon season, suggesting the significant impact of convective activity on temporal variations of precipitation stable isotopes. During April, and May of 2016 and 2017, variation of precipitation stable isotopes are probably related with the mixing of multi-moisture combined with the westerlies transport. Our study suggested that the moisture transport processes are the main controls of precipitation stable isotopes at Kathmandu.

Background and aims : Lack of effective pharmacotherapies for nonalcoholic fatty liver disease (NAFLD) is mainly attributed to an insufficient research on its pathogenesis. In this paper, we investigated the role of TM6SF2 on fatty acid metabolism in the background of fatty liver, and proposed the possible therapeutic strategies of NAFLD caused by TM6SF2 deficiency. Methods Liver samples collected from both NAFLD mouse models and human subjects, and RNA-seq data retrieved from GEO database were used to evaluate the expression of TM6SF2 in NAFLD. Knockdown of TM6SF2 was performed for clarifying the mechanistic basis of hepatic lipid accumulation in NAFLD. After confirming that TM6SF2 deficiency would cause an abnormality in fatty acid metabolism, MK-4074 administration served as the therapeutic intervention to evaluate its effect on NAFLD caused by TM6SF2 deficiency. Results Hepatic TM6SF2 levels are elevated in both NAFLD patients and mouse NAFLD models. In vivo and in vitro experiments confirmed that TM6SF2 knockdown increases intracellular lipid deposition due to dysregulated fatty acid metabolism in the context of TM6SF2 deficiency, being characterized by enhanced fatty acid uptake and synthesis, accompanied by impaired fatty acid oxidation. Moreover, MK-4074 treatment could reverse the NAFLD phenotypes caused by TM6SF2 deficiency. Conclusions TM6SF2 deficiency enhanced hepatic lipid accumulation through dysregulated fatty acid metabolism and MK-4074 treatment could alleviate the NAFLD phenotypes caused by TM6SF2 deficiency.

Purpose: Liver hepatocellular carcinoma (LIHC) is one of the most common primary malignant liver tumors worldwide. The RAD52 motif-containing protein 1 (RDM1) has been shown to play a role in mediating DNA damage repair and homologous recombination. The present study was designed to determine the expression of RDM1 and its prognostic value as well as its relationship with immune infiltration in LIHC patients. Methods: Oncomine and Tumor Immunoassay Resource were used to assess the expression of RDM1. PrognoScan and Kaplan–Meier bioinformatics database were used to analyze the impact of clinical influencing factors on prognosis. Finally, the Tumor Immune Assessment Resource (TIMER) and Gene Expression Analysis Interactive Analysis (GEPIA) databases were used to detect the correlation between the expression of RDM1 and expression of marker genes related to immune infiltration. Immunohistochemistry (IHC) method was used to detect the expression level of RDM1 in 90 cases of hepatocellular carcinoma and adjacent normal liver tissues. Results: RDM1 expression was up-regulated in most cancers. The expression of RDM1 was remarkably higher than that of the corresponding normal control genes in LIHC tissues. The increase in RDM1 messenger RNA (mRNA) expression was closely related to the decreases in overall survival (OS) and progression-free survival (PFS). Additionally, the increase in RDM1 mRNA expression was closely related to the infiltration levels of macrophages, CD8+ T cells and B cells and was positively correlated with a variety of immune markers in LIHC. Conclusion: The findings of the present study demonstrate that RDM1 is a potentially valuable prognostic biomarker that can help determine the progression of cancer and is associated with immune cell infiltration in LIHC.

Catalytic performances of Mn2O3 nanoparticles for peroxymonosulfate (PMS) activation in bisphenol A (BPA) degradation were comprehensively investigated in this study. Experimental results showed that 10 mg/L BPA could be 100% degraded within 20 min with the dosages of 0.2 g/L Mn2O3 and 0.1 mM PMS. Moreover, Mn2O3 showed remarkable activity in activation of PMS and excellent adaptability in various real water matrices, including river water, tap water and secondary effluents. Based on the radical detection and scavenging experiments, it was found that both radical and non-radical oxidation contributed to the degradation of BPA and 1O2 was the dominant species in the degradation compared to •OH, SO4•− and O2•−. A total of 15 transformation products were identified by LC/MS-MS during BPA degradation in the Mn2O3/PMS system, and degradation pathways via three routes are proposed. Compared with lab-made catalysts reported in the literature, the Mn2O3 catalyst demonstrated its superiority in terms of its high TOC removal, low PMS consumption and fast degradation rate for BPA.

The Dongzigou Pb-Zn deposit is located in the south-eastern margin of Yangtze block, Midwest China. Ore bodies are hosted in Sinian carbonate rocks. The main metallic minerals are sphalerite and galena, while the non-metallic minerals are dolomite, barite, and quartz. Three stages of hydrothermal mineralization are an early quartz-pyrite stage (stage I), a middle sphalerite-galena stage (stage II), and a late sphalerite-barite stage (stage III). The main types of fluid inclusions for the Dongzigou deposit are liquid-rich inclusions (L0-type). Laser Raman analysis indicates that the fluid inclusions within the hosted minerals are dominated by H2O. Given the fluid inclusion data, the homogenization temperatures range from 220.0–300.0 °C (stage I), 126.7–243.9 °C (stage II), and 117.0–201.0 °C (stage III), respectively. Fluid salinities range from 3.4–11.8 wt% NaCl eq. (stage I), 3.6–10.7 wt% NaCl eq. (stage II), and 2.0–6.5 wt% NaCl eq. (stage III), respectively. Indicating that the ore-forming fluid of the Dongzigou deposit tends to decrease in salinity and homogenization temperature during the fluid evolution process. The δD (−63.4% to −49.8%) and δ18OH2O (0.6 to 13.7%) data from stage I to stage III which indicate that the ore-forming fluids derived from formation water, and in the late stage of hydrothermal mineralization mixed with meteoric water. The LA-ICPMS results show that sphalerite enriched Cd (1272–3437 ppm), Ge (201–717 ppm), and Ga (0.1–130 ppm), but poor in In (0.01–0.1 ppm). Through comparative studies with the trace elements of sphalerite from different types of Pb-Zn deposits, it is found that the trace element characteristics of the Dongzigou deposit are most similar to the MVT deposits. Overall, the Dongzigou Pb-Zn deposit is an atypical MVT deposit, and the salinity of fluid inclusions is lower than that of typical MVT deposits.

We report a new type of nano-optical tip, the quantum dot decorated nano-pyramid fiber tip, for scanning near-field optical microscopy. The nano-pyramid tip has a large apex angle (70.5 degree), and consequently exhibits a significant improvement (17-fold) of the signal collection efficiency compared to conventional tapered fiber tips. Moreover, thanks to the template-based fabrication method and the surface treatment technique, the quantum-dot decorated nano-pyramid tip enjoys a clean and smooth surface, and can be produced with high accuracy and high reproducibility. Experimental results show that, with the nano-pyramid tip, the optical field distribution of a photonic nanostructure can be mapped with a 20 nm resolution ( λ /20). It provides a powerful and reliable tool for near-field optical measurements.

To obtain the ultrafine pigment for ink-jet printing, ultrafine spherical Pr-ZrSiO4 pigment was prepared by sol-gel-microemulsion method (S-G-M). In the emulsion, ZrO2 and SiO2 sols are used as water phase, cyclohexane serves as oil phase, Triton X-100 and 1-hexanol are chosen as surfactant and co-surfactant, respectively. The results show that without the introduction of demulsifier, the sol/oil microemulsion system is demulsified automatically due to the transformation of liquid/liquid to solid/liquid interface following the transformation from sol to gel. The obtained Pr-ZrSiO4 pigment owns uniform spherical particles with the average particle size of about 0.785 μm, which is suitable for the ink-jet printing. The CIE coordination of the pigment is L* = 87.63, a* = −3.82, b* = 65.68, which shows bright lemon yellow. Hence, the ultrafine pigment in this work has the good application prospects.

Chinese auditing standards mandate the disclosure of critical audit matters (CAMs) in audit reports for all listed companies since 2017. Risk-oriented auditing requires auditors to assess material ...

Microparticles covered with double-layered coatings are developed for in-depth conformance control to enhance oil recovery within heterogeneous reservoirs. The proposed bilayer-coating microspheres (BCMS) can transport deeply into a porous media, owing to the rigid outer layer designed for protecting the adhesive inner coating. The objective of the present work is to characterize the adhesion property and the plugging behavior of BCMS at reservoir temperature and fluid salinity. A series of static and coreflood tests are conducted. BCMS exhibits resistance to high temperature and high salinity and shows a great ability of deep transport into porous media. A mathematical model for the deep-bed filtration of BCMS in porous media is developed, accounting for the limited retention concentration and the velocity difference between the suspended particles and the carrier fluid. Modeling results match the measured pressure drop histories in coreflood tests with high accuracy, which validates the proposed analytical model. BCMS shows promising potential for application in production enhancement in hydrocarbon reservoirs.

Fines migration with consequent well productivity reduction is a well-known phenomenon occurring during exploitation of geothermal reservoirs. Laboratory corefloods with piecewise constant decreasing ionic strength have been performed with measurements of the pressure drop along the core and the accumulated effluent particle concentration. The tests were performed under ambient conditions with further results re-calculation for high geothermal temperatures. Permeability stabilises after injection of numerous pore volumes, suggesting slow drift of mobilised particles if compared with the carrier water velocity. SEM-EDX analysis of the produced fine particles shows that kaolinite and illite/chlorite are the major minerals responsible for the permeability damage. The competitive effects of decreasing water viscosity and weakening electrostatic attraction on the attached particle concentration during temperature increase have been observed. The micro modelling of the fine particle mechanical equilibrium shows that the electrostatic attraction effect on the fines attachment dominates. It results in increased fines detachment and permeability decline at high temperatures, suggesting that geothermal fields are more susceptible for fines migration formation damage than the conventional oilfields and aquifers. A new “ionic strength- velocity” translation procedure is developed for determining velocity dependency of the maximum retention function from laboratory coreflood tests with varying ionic strength. Experiment-based evaluation of velocity- and temperature-dependencies on the maximum retention function is demonstrated for specific conditions of geothermal resevoirs. We discuss well inflow performance with fines migration, and derive an exact solution for axi-symmetric water-flow towards the well. The solution includes explicit formulae for attached, suspended and strained fines, and well productivity. The analytical model along with the obtained laboratory data allows successful matching of the well discharge history (Salamander geothermal field, Australia).

The theory of audit pricing suggests that audit fees are positively associated with areas of higher inherent risk. Inventory is commonly cited as one such area, and many Western studies have reported a positive association between inventory and audit fees. However, most Chinese studies have reported a significant negative association. This study finds that this puzzling association is attributable to Chinese auditors charging a significant discount on the opening balance of inventory, whereas their U.S. counterparts charge a significant premium. Meanwhile, we show that opening-balance inventory is associated with higher inherent risk both in China and the U.S. On the other hand, both Chinese and U.S. auditors charge a significant discount on the net increase in inventory as of the current year end, and we show that this is associated with lower inherent risk. Therefore, Chinese auditors appear to underreact to the inherent risk associated with opening-balance inventory, which helps explain the puzzling negative association between inventory and audit fees in China.

During micro-scale tracer flow in porous media, the permeability and fluid velocity significantly affect the fluid dispersion properties of the media. However, the relationships between the dispersion coefficient, permeability, and fluid velocity in core samples are still not clearly understood. Two sets of experiments were designed to study the effects of tracer fluid flow velocity and porous medium permeability on the dispersion phenomenon in a core environment, using natural and sand-filled cores, respectively. From experimental data-fitting by a mathematical model, the relationship between the dispersion coefficient, flow velocity, and permeability was identified, allowing the analysis of the underlying mechanism behind this phenomenon. The results show that a higher volumetric flow rate and lower permeability cause a delay in the tracer breakthrough time and an increase in the dispersion coefficient. The core experimental results show that the dispersion coefficient is negatively correlated with the permeability and positively correlated with the superficial velocity. The corresponding regression equations indicate linear relations between the dispersion coefficient, core permeability, and fluid velocity, resulting from the micron scale of grain diameters in cores. The combination of high velocity and low permeability yields a large dispersion coefficient. The effects of latitudinal dispersion in porous media cannot be ignored in low-permeability cores or formations. These findings can help to improve the understanding of tracer flow in porous media, the design of injection parameters, and the interpretation of tracer concentration distribution in inter-well tracer tests.

The accuracy of retrieving the CAD file corresponding to the cut-piece from the CAD library determines the efficiency of the cut-piece automatic detection system and the digital management of the cut-piece inventory. However, the materials of the cut-piece are complex and diverse (including cowhide, artificial leather, fabric, etc.), contain multi-layered shapes and structures, and are prone to deformation. The traditional registration algorithms cannot satisfy the accurate registration between CAD and cut-piece. In order to solve the problem of high-frequency translation and complex shape of the cut-piece, we propose an image retrieval algorithm based on representation learning. This paper takes FaceNet as the basic framework. First, the loss function combining Softmax loss and center loss is used to maintain the discriminant ability between classes and optimize the cohesion of the ternary loss function. Second, the BlurPool module is used to enhance the anti-aliasing of the downsampling process and enhance the translation invariance of the network while maintaining network performance. Finally, the multi-feature deep fusion (FRE) module designed in this paper is used to solve the problem of reduced model expression ability caused by different sizes of cut-piece. A series of experiments on our dataset show that the proposed representation learning network is more accurate in the SVM classifier, and it only takes 30ms to predict a single cut-piece.

Foam-assisted steam flooding is a promising technique to alleviate gas channeling and enhance sweep efficiency in heterogeneous heavy-oil reservoirs. However, long-term foam stabilization remains problematic at high temperatures. Three-phase foam (TPF), containing dispersed solid particles, has been proposed to improve foam stability under harsh reservoir conditions. We fabricated a novel TPF system by adding ultrafine fly ash particles, as well as high-temperature resistant microspheres with an adhesive coating layer. This work aims at assessing the ability of the generated TPF in controlling steam channeling and enhancing oil recovery. Static and core flood tests were performed to evaluate foam strength and stability. Our results suggested a stronger foamability at a lower consolidation agent concentration, while a longer half-life period of foam and settling time of solid particles at a larger consolidation agent concentration were observed. Bubbles suspended independently in the liquid phase, with sizes varying from 10 to 100 μm, smaller than that of the conventional foam, suggesting a significant enhancement of foam dispersity and stability. The plugging rate was close to 90% when the temperature was as high as 300 °C, demonstrating a well-accepted plugging effect under high temperatures. A larger pore volume injection of TPF yielded a higher EOR in parallel cores, which substantiated the effectiveness of the three-phase foam system in sealing high-permeability channels.