Flow behavior of a coupled model between horizontal well and fractal reservoir

Many research findings have proven that the system of porous medium reservoirs exhibits different heterogeneous structures at various scales,demonstrating some form of self-similarity with fractal characteristics.In this paper,fractal theory is incorporated into the reservoir to investigate coupled flow between reservoir and horizontal well.By examining the pore structure of highly heterogeneous reservoirs,the fractal dimension can be determined.Analytical methods are utilized to solve the Green function of a point source in a reservoir with fractal characteristics.Employing Green's function and the principle of spatial superposition,a finite flow model for a horizontal well coupled with a fractal reservoir is developed to calculate the flow rate and flow profile of the horizontal well.The model also accounts for the impact of wellbore friction and is solved numerically.A specific example is used for calculation to analyze the influence of fractal parameters on the production and flow rate of the horizontal well.When considering the fractal characteristics of oil reservoirs,the flow rate of the horizontal well is lower than that in Euclidean space.As the fractal dimension increases,the connectivity of pores in the reservoir improves,making it easier to drive the fluid into the wellbore,and the flow distribution along the wellbore becomes more uniform.Conversely,as the anomalous diffusion index increases,the connectivity between pores deteriorates,thus the distribution of flow rate along the wellbore becomes more uneven.

Evaluation of contrast-enhanced ultrasound for diagnosis of dysplastic nodules with a focus of hepatocellular carcinoma in liver cirrhosis patients

Objective： To compare the enhancement features of dysplastic nodnles with a focus of hepatocellular carcinoma （DN-HCC） versus HCC and regenerative nodules （RN） in cirrhotic patients. Methods： One hundred and ninety-three cirrhotic patients were enrolled in this study; they had 215 focal liver lesions, 1.0-3.5 cm in size, which were examined using contrast-enhanced ultrasound （CEUS） with SonoVue and diagnosed as HCC, RN or DN-HCC by biopsy. Samples were obtained using 18-gauge needles in the different enhanced areas. The enhancement features of DN-HCC, HCC and RN were evaluated. Results： There were 86 HCC lesions, 102 RN lesions, and 27 DN-HCC lesions diagnosed by biopsy. Of 86 HCC lesions, 87.2% （75/86） showed complete enhancement during the arterial phase, and 12.8% （11/86） had inhomogeneous enhancement, with no enhancement in the central area during the arterial phase; 100% （86/86） exhibited washout during the late phase. Of 102 RN lesions, 95.1% （97/102） had delayed or simultaneous enhancement during the arterial phase, and 4.9% （5/102） displayed slight enhancement during the arterial phase; 26.5% （27/102） exhibited washout and 73.5% （75/102） exhibited no washout during the late phase. In 27 DN-HCC lesions, only part of the lesions enhanced during the arterial phase and washed out during the late phase; the other areas had delayed or simultaneous enhancement during the arterial phase, and 29.6% （8/27） exhibited slight washout in the late phase. In 86 HCCs, the pathological feature was HCC in the enhanced area of 75 lesions, hepatocellular fatty degeneration in the slightly enhanced area of 7 lesions, and hepatocellular necrosis in the unenhanced area and HCC in the enhanced area of 4 lesions. In 102 RNs, the pathological diagnosis was hepatocyte proliferation with or without fatty degeneration. In 27 DN-HCCs, the pathological feature was HCC in the enhanced area and hepatocye regeneration in the unenhanced area. Conclusions： CEUS is useful for the diagnosis of focal liver lesions in cirrhotic patients. CEUS can help determine the progression from RN to DN-HCC to HCC by analyzing the hemodynamics. CEUS can promote the diagnostic accuracy of a biopsy by providing more accurate information on the site of the biopsy.

The Bethesda System for Reporting Thyroid Cytopathology(TBSRTC):A report of 2,781 cases in a Chinese population

Objective:To evaluate the diagnostic utility of The Bethesda System for Reporting Thyroid Cytology(TBSRTC)at Peking University Cancer Hospital,the incidence of noninvasive follicular thyroid neoplasms with papillary-like nuclear features(NIFTP),and the impact of reclassification on cytopathological outcomes.Methods:We performed a retrospective study of thyroid fine-needle aspiration(FNA)cases between April 2014 and March 2019.The FNA results were classified according to TBSRTC.Post-surgery histological findings were followed up.Results:A total of 2,781 thyroid FNAs were performed.The incidences of the 6 diagnostic categories(DCs I-VI)were 14.8%,17.1%,15.8%,2.3%,11.6%and 38.5%,respectively.A total of 1,122 patients(40.3%)had corresponding histological results.NIFTP accounted for 0.4%of papillary thyroid carcinoma(PTC)cases,and there was no significant difference in the risk of malignancy(ROM)for each TBSRTC DC between"NIFTP=carcinoma(Ca)"and"NIFTP≠Ca".When"NIFTP=Ca",the sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV),and accuracy of TBSRTC were 98.0%,84.0%,99.4%,58.3%,and97.5%,respectively.When"NIFTP≠Ca",the sensitivity,specificity,PPV,NPV and accuracy of the TBSRTC were 98.1%,81.5%,99.3%,61.1%,and 97.5%,respectively.Conclusions:TBSRTC is effective in the preoperative diagnosis of thyroid nodules in Peking University Cancer Hospital.The impact of the reclassification of NIFTP on cytopathological outcomes is limited because of its low incidence,and the revised ROMs are not suitable for Asian patients.

Effects of organic mulching on soil aggregate stability and aggregate binding agents in an urban forest in Beijing, China

Urban forest soil is often disturbed by rapid urbanization. Organic mulching is effective for improving soil quality and aggregate stability. This study evaluated how soil binding agents changed aggregate stability through organic mulching in urban forest soils. Three treatments were applied in Jiufeng National Forest Park, Beijing: (1) no organic mulch (control);(2) wood chips alone (5 cm thickness);and, (3) wood chips + wood compost (This mulch was divided into two layers, the upper layer of wood chips (2.5 cm), the lower layer wood compost (2.5 cm)). Soil samples were collected from the surface 10- cm soil layer and fraction into four aggregates. Glomalin-related soil protein and soil organic carbon were measured in bulk soil and the four aggregates. The results show that wood chips + wood compost increased the proportion of large and small macroaggregates, mean weight diameter and geometric mean diameter. The total and easily extractable glomalin-related soil protein were higher in the wood chips + wood compost. However, soil organic carbon was lower in the wood chips alone application compared to the controls and wood chips + wood compost. Easily extractable / total glomalin-related soil protein and glomalin-related soil protein / soil organic carbon ratios of wood chips alone and wood chips + wood compost had increased trend compared to the controls but did not reach significant levels (p > 0.05). Mean weight diameter and geometric mean diameter correlated positively with total and easily extractable glomalin-related soil protein but were not positively correlated with soil organic carbon, the ratios of easily extractable and total glomalin-related soil protein, and the ratios of glomalin-related soil protein and soil organic carbon. Redundancy analysis revealed that total glomalin-related soil protein was the most important driver for soil aggregate stability, especially the total glomalin-related soil protein of small macroaggregates. The results suggest that wood chips + wood compost enhanced soil aggregate stability through the increase of glomalin-related soil protein. Wood chips alone cannot enhance soil aggregate stability in urban forests in the short term.

Effects of the transverse electric field on nanosecond pulsed dielectric barrier discharge in atmospheric airflow

In this paper,an asymmetric electrode geometry(the misalignment between the ends of highvoltage and grounded electrodes)is proposed in order to investigate the effects of the transverse electric field on nanosecond pulsed dielectric barrier discharge(DBD).The results show that diffuse discharge manifests in the misaligned region and the micro-discharge channel in the aligned region moves directionally.Moreover,the diffuse discharge area increases with the decrease of the discharge gap and pulse repetition frequency,which is consistent with the variation of the moving velocity of the micro-discharge channel.When airflow is introduced into the discharge gap in the same direction as the transverse electric field,the dense filamentary discharge region at the airflow inlet of asymmetric electrode geometry is larger than that of symmetric electrode geometry.However,when the direction of the airflow is opposite to that of the transverse electric field,the dense filamentary discharge region of asymmetric electrode geometry is reduced.The above phenomena are mainly attributed to the redistribution of the space charges induced by the transverse electric field.