f. zhang

Due to the important strategic position of Pumped Storage Power Plants (PSPP) in global energy upgrading, conducting in-depth research on the various operating conditions of pump turbine units is important for their safe and stable operation. This study sought to clarify the gas–liquid phase motion and the nonlinear chaotic characteristics of the process of exhaust and pressurization in pump mode; with the simplified objective model proposed here, a visualization of the process is achieved using data-driven methods, and the nonlinear characteristics of gas–liquid phase motion during the process are theoretically demonstrated. A method that combines data-driven and chaotic analysis is proposed to qualitatively and quantitatively analyze the force and torque time-series signals of the runner under different exhaust rates. The results indicate that the chaotic characteristics of the force signals and torque signals of the runner are not in a single linear relationship with the exhaust rates. Therefore, this research also provides guidance on exhaust rates with the aim of informing actual engineering practice, the purpose of which is to reduce the vibration amplitude caused by repetitive torque and improve the stability of the unit operations.

The To investigate the feasibility, efficacy, and toxicity of three-dimensional conformal radiotherapy (3D-CRT) for treatment of patients with advanced hepatocellular carcinoma (HCC) complicated by portal vein tumor thrombosis (PVTT) and/or inferior vena cava tumor thrombosis (IVCTT).

53 HCC patients with PVTT/IVCTT undergoing 3D-CRT during the period from September 2008 to January 2014 were analyzed. The Kaplan-Meier method was used to analyze between-group differences in patient baseline information. Univariate and multivariate cox regression analyses were used to identify factors affecting survival in patients with HCC.

Computed tomography (CT) scan or MRI (Magnetic Resonance Imaging) of the upper abdomen one month post-radiotherapy showed an overall response rate (CR + PR) of 56.6% (30/53). Univariate analysis revealed that treatment regimen (P = 0.008), alpha fetoprotein (AFP) level (P = 0.012), response to radiotherapy, metastasis to celiac lymph nodes and site of tumor thrombosis were strongly associated with the prognosis of HCC patients with PVTT (P = 0.000). The median survival time was 9 months (95% CI: 7.43-10.57 months) in 23 (43.4%) PVTT patients, and 24 months (95% CI: 20.04-27.96 months) in 30 (56.6%) IVCTT patients. Multivariate Cox regression analysis revealed that metastasis to celiac lymph nodes (P = 0.004) and response to radiotherapy (P = 0.001) were independent factors affecting patients’ survival.

3D-CRT has high efficacy for treating HCC patients with PVTT, and metastasis to celiac lymph nodes and response to radiotherapy are primary factors affecting HCC patients’ survival.

Semi-open centrifugal pump has the disadvantage of low efficiency in chemical industry for its unique structure. For the purpose of improving its efficiency as much as possible on the premise of meeting the head demand, in this case, an optimization strategy combining Bezier curve, Genetic Algorithm (GA), Fuzzy Logic (FL), Artificial Neural Network (ANN) and solution space model based on stratified sampling is proposed to optimize the efficiency of semi-open centrifugal pump. The fourth-order Bezier curve is used as parametric method to control the blade profile, GA combined with FL is used as optimization strategy to seek the optimal individual. Besides, the optimization solution space based on stratified sampling method and ANN training are used to shorten computing time. Finally, the semi-open centrifugal pump corresponding to the optimal parameter combination of blade profile has been found, and on the premise of meeting the head requirements, the efficiency has been significantly improved. Entropy production rate is carried out to analyze the reason of efficiency improvement. The whole optimization strategy proposed in this study provides a good reference for parametric control and performance optimization of bladed pump.

In this paper, a test system based on the Nano-tracer Planar Laser Scattering (NPLS) technique for studying time evolution of unsteady flow structures was finished. Based on this system, the experimental study on the interactions between the incident shock wave and the turbulent boundary layer of the incoming wall was performed. The experiments were performed in a Mach 3.4 supersonic low-noise wind tunnel at the unit Reynolds number of 6.30 × 106 /m-1 . For the first time, five frames of temporal-correlated fine structure images of transient flow field with shock wave and the turbulent boundary layer interactions (SWTBLI) were obtained under the experimental conditions, and the spatiotemporal evolution characteristics of the flow structure were analyzed. At the same time, the flow field characteristics of temporal-correlated images were studied when the density boundary layer thickness of incoming turbulent layer is δ1 = 0.55δ, δ2 = 0.72δ, δ3 = 0.87δ respectively. During the development of vortex structure in the boundary layer from turbulent boundary layer to separation bubble, the oscillation interval distribution law of induced shock wave was summarized, and the group velocity of vortex structure development in the boundary layer and the relationship between boundary layer thickness and physical space size growth law of separation bubble under different incoming turbulent boundary layer thicknesses were obtained. The results also show that with the increase of the incoming boundary layer thickness, the group velocity in the development process of vortex structure in the turbulent boundary layer does not change significantly. As the thickness of the boundary layer entering the separation bubble increases, the overall growth height of the separation bubble also increases.

Feeding ecology of Acrossocheilus yunnanensis, a dominant fish in the headwaters of the Chishui River, a tributary of the upper Yangtze River, was studied using the analysis of gut contents. From March 2015 to January 2016, a total of 543 individuals were collected and analyzed. The results showed that A. yunnanensis was an omnivorous fish mainly feeding on chlorophytes, diatoms, and aquatic insects. The trophic level was 2.69±0.62 (mean±SD), signifying A. yunnanensis as a primary or secondary predator. Dietary shifts were found among different ontogenetic stages and seasons. Specifically, young individuals fed primarily on aquatic insects and diatoms, whereas older fish fed mainly on chlorophytes. In spring, the preferred food item was aquatic insects and in other seasons, chlorophytes became the predominant prey. Diet composition showed no differences among individuals of different sex and diel periods. The feeding intensity of A. yunnanensis was not affected by diel periods, suggesting this species feeds continuously. However, its feeding intensity was significantly influenced by seasons. Pairwise comparison found that the feeding intensity was higher in spring and autumn than that in summer and winter, with minimum food intake in winter and maximum in spring. Analysis on Amundsen graph and niche breadth index indicated that A. yunnanensis might pursue an opportunistic and moderately generalized feeding strategy, which could explain why it has become the dominant fish species in our study area.