فهرست مطالب x. yang

To investigate the gas-liquid two-phase flow characteristics in an emergency rescue drainage pump, the MUSIG model was adopted to analyze the effect of the gas phase on the internal flow characteristics of the pump. The results show that the gas phase predominantly accumulated in the impeller region, with significant tendencies for large diameter bubbles to fragment into smaller diameter bubbles. The bubbles of the impeller blades converged towards the middle zone of the blade near the hub, forming an air pocket that obstructed the flow passage through the impeller. Such findings ultimately resulted in a loss of pump performance. Moreover, as the diameter of inlet bubble increased, there was a greater tendency for the gas phase to converge into a concentration distribution, leading to unfavorable flow conditions in the pump. This phenomenon ultimately led to a decline in pump performance and may have resulted in the loss of water conveyance functionality. Meanwhile, the Ω method was used to investigate the vortex flow within the drainage pump under different gas contents. As the inlet gas volume fraction increased, the vortex area expanded and the vortex tended to fragment into multiple smaller pieces, resulting in the formation of more complex structures.

With the escalating integration of Electronic Control Units (ECUs) in contemporary vehicles, the intricacy of vehicle networks is incessantly advancing. Diagnostic communication, as a pivotal facet within these networks, grapples with protracted development cycles and heightened intricacies. In a bid to augment software reusability and portability, this study meticulously scrutinized pertinent research and proffered an electric vehicle fault diagnosis system predicated on the Controller Area Network (CAN) bus, leveraging the diagnostic communication architecture advocated by the AUTOSAR standard. The integration of AUTOSAR seeks to pioneer an innovative software development paradigm for automotive fault diagnosis systems, thereby remedying extant limitations. The communication and diagnostic module of this study were instantiated using AUTOSAR, thereby obviating the necessity for developers to immerse themselves in hardware intricacies and communication implementations. This allows developers to focalize their efforts on crafting software features for fault diagnosis. Empirical results illustrate that the single-core CPU utilization rate of the proposed method in this article stands at 40.68%, with a fault detection time of 0.0217. The success rate of fault detection is 98.70%, indicating an increase of 12.97% and 8.98% when compared to the CAN bus and structural analysis methods, respectively. Testing indicators are significantly mitigated, yielding more precise fault detection outcomes. The exploration of this avant-garde software development methodology in automotive electronic products markedly amplifies the efficiency of automotive troubleshooting system software, underscoring its potential for academic contribution and application in real-world scenarios.

The aim of this study was to evaluate the influence of lesion size on the performance of real-time two-dimensional shear wave elastography (2D-SWE) in the diagnosis of breast lesions.

A total of 118 consecutive female patients with 129 breast lesions (50 malignant and 79 benign) who underwent surgical excision and/or core biopsy were studied. The lesions were categorized into three subgroups according to their size: (1) group 1: < 1.0 cm3; (2) group 2: 1.0–4.0 cm3; (3) group 3: > 4.0 cm3. The maximum elasticity (Emax), mean elasticity (Emean), and their standard deviation (SD) in the three subgroups were compared and analyzed in terms of the cutoff values acquired by pathological results.

The lesion size significantly differed between benign and malignant masses (P < 0.05). Malignant lesions exhibited significantly elevated values of Emax, Emean, and SD, compared with benign lesions in the three subgroups. The optimal threshold was higher for larger malignant and benign lesions (P < 0.05). In malignant lesions, the SWE parameters in group 1 were significantly different from those in groups 2 and 3. The area under the receiver operating characteristics curve (AUROC) of SD was higher than that of Emax and Emean in all three subgroups.

The values of 2D-SWE parameters  increase with the increase in size of a breast mass, and the adjustment of the threshold based on lesion size yields a more accurate diagnosis. Among the SWE parameters, SD has the best diagnostic performance.

The flow fields around vehicle drag reduction devices are three-dimensional, complicated, and unsteady. Meanwhile, the small scale of the drag reduction device brings more challenges to the simulation. An Improved Delayed Detached Eddy Simulation (IDDES) was applied to study the effect of two types of drag reduction device. First, the flow field of an Ahmed body at a 25° slant was simulated in detail using IDDES and verified by experiment data. Afterwards, the flow field structures of adding-on vortex generators (VGs) and riblets on the rear and slant surface of the Ahmed body were studied. The simulation results of the velocity, pressure and vortex structure on the controlled case are presented by comparing with the baseline model to illustrate the drag reduction mechanism. The two drag-reduction devices had different flow mechanisms and significantly affected the development of the separation vortex near the rear and slanted surface. A maximum drag reduction of 6.21% could be achieved using VGs on the rear surface. Finally, four combinations of those two devices were investigated. The results demonstrated that suitable combinations can further decrease the aerodynamic drag, and an 8.62% drag reduction is achieved.

To evaluate the predictive value at the hepatobiliary phase (HBP) magnetic resonance imaging (MRI) after gadobenate dimeglumine (Gd-BOPTA) injection for histologic grades of hepatocellular carcinoma (HCC).

HCC patients who underwent Gd-BOPTA-enhanced MRI were analyzed and divided into four histologic grades of differentiation based on Edmonson-Steiner grade. Besides, HCC tumor differentiations grade I, II and III, IVwere defined as well-differentiated (WD), moderately-differentiated (MD), poorly-differentiated (PD), respectively. The clinical, pathological and imaging features of patients were assessed. Receiver operating characteristic (ROC) curve was to evaluate the significance between WD/MD HCC and PD HCC using the apparent diffusion coefficient (ADC), relative intensity ratio (RIR) of T1WI and T2WI (T1RIR, T2RIR), contrast-enhancement ratio in arterial phase (CERA) and contrast-noise-ratio (CNR) in HBP (CNRhbp).

A total of 102 HCC patients were analyzed (grade I,  n=19; grade II, n=30; grade III, n=30; grade IV, n=23). There was no statistical difference regarding to the pathological and clinical features among four grades. There were significant differences in CERA, CNRhbp, T1RIR, T2RIR and ADC values among the four HCC grades (all P<0.05). Based on ROC curve, comparison of the five quantitative MRI parameters indicated ADC (sensitivity 84.8%, specificity 82.6%, AUC 0.862) and CNRhbp value (sensitivity 78.5%, specificity 91.3%, AUC 0.916) could significantly distinguish the HCC histological grade.

The ADC and/or CNRhbp value in HBP-MRI after GD-BOPTA injection might be as the significant quantitative parameters to distinguish HCC histological grade.

In the present study, an experimental method is proposed to study the influence of different slot widths, positions and structures of the compressor recirculation systems on the compressor performance. Obtained results indicate that the compressor flow range increases with the width of the recirculation slot at the expense of a narrower high-efficiency operating region. It is found that when the slot width is set to 3 mm, the surge and choke margins are about 12% higher than that of the 2 mm slot. Moreover, it is found that when the position of the recirculation slot falls in the middle area of the guide wheel and far from the splitter blades, a larger surge margin can be achieved then it near the splitter blade. Adopting the recirculation structure without intake retaining ring structure can effectively broaden the compressor flow range. Compared with a straight slot intake structure, the compressor with an inclined slot intake structure has a greater surge margin in the high-speed region; however, the high-efficiency range of the latter scheme is smaller. Furthermore, the efficiency circle moves towards higher mass flow conditions. The present parametric study is expected to provide a guideline to design recirculation devices.

The Sturm-Liouville boundary value problem of the multi-order fractional differential equation    D α 0+ [p(t)D β 0+ u(t)] + q(t)f(t, u(t)) = 0, t ∈ (0, 1), a limt→0 t 1−βu(t) − b limt→0 t 1−α p(t)D β 0+ u(t) = 0, c limt→1 u(t) + d limt→1 p(t)D β 0+ u(t) = 0 is studied. Results on the existence of solutions are established. The analysis relies on a weighted function space and a fixed point theorem. An example is given to illustrate the efficiency of the main theorems. Keywords: multi-order fractional differential equation, SturmLiouville boundary value problems, fixed-point theorem.

The Sturm-Liouville boundary value problem of the multi-order fractional differential equation    D α 0+ [p(t)D β 0+ u(t)] + q(t)f(t, u(t)) = 0, t ∈ (0, 1), a limt→0 t 1−βu(t) − b limt→0 t 1−α p(t)D β 0+ u(t) = 0, c limt→1 u(t) + d limt→1 p(t)D β 0+ u(t) = 0 is studied. Results on the existence of solutions are established. The analysis relies on a weighted function space and a fixed point theorem. An example is given to illustrate the efficiency of the main theorems.