Dynamic-Area-Based Shortest-Path Algorithm for Intelligent Charging Guidance of Electric Vehicles

With the increasing popularization and competition of electric vehicles (EVs), EV users often have anxiety on their trip to find better charging stations with less travel distance. An intelligent charging guidance strategy and two algorithms were proposed to alleviate this problem. First, based on the next destination of EV users’ trip, the strategy established a dynamic-area model to match charging stations with users’ travel demand intelligently. In the dynamic area, the Dijkstra algorithm is used to find the charging station with the shortest trip. Then, the area extension algorithm and the charging station attribution algorithm were developed to improve the robustness of the dynamic area. The two algorithms can automatically adjust the area size according to the number of charging stations in the dynamic area to reduce the number of nodes traversed by the Dijkstra algorithm. Finally, simulation examples were used to verify the effectiveness of the proposed model and algorithms. The results showed that the proposed intelligent charging guidance strategy can meet the travel demand of users. It is a promising technique in smart cities to find better travel trips with less travel distance and less computed time

Investigation of Electro-Thermal Performance for TreeFET from the Perspective of Structure Parameters

In this work, the electro-thermal properties of TreeFET, which combines vertically stacked nanosheet (NS) and fin-shaped interbridge (IB) channels, are investigated in terms of interbridge width (WIB), nanosheet space (SNS) and nanosheet width (WNS) by TCAD simulation. Electrical characteristics such as electron density distributions, on/off-state current (ION, IOFF), subthreshold swing (SS) and self-heating effects (SHE) such as lattice temperature and thermal resistance (Rth) are systematically studied to optimize the performance of TreeFET. The result shows that a smaller WIB mitigates the short-channel effects and increases the electron concentration in NS channels but increases thermal resistance. A larger SNS increases the on-state current while compensating for the gate drive loss and mitigating the thermal coupling effect between NS channels but results in longer conduction paths of carriers and heat, which hinders further improvements. Moreover, a suitable WNS is required to lessen the decline of gate controllability induced by IB channels. Hence, suitable geometry parameters should be selected to achieve a compromise between thermal and electrical performance

Experimental and Simulation Research on the Influence of Stirring Parameters on the Distribution of Particles in Cast SiCp/A356 Composites

Achieving the uniform distribution of reinforcement particles in MMCs is very important for the effect of stirring parameters and the flow action of the melt, which should be known. The effect of stirring parameters on the distribution of SiC particles in SiCp/A356 composites was studied by the experimental and numerical methods in this paper. The experimental results show the SiC distribution with different stirring parameters. In addition, the effects of the fluid velocity and volume fraction of SiC particle at different position of crucible on the SiC distribution were analyzed by numerical simulation. The velocity magnitude, axial velocity, and radial velocity were analyzed to explain theoretically the particle distribution. The shearing force, moments, and stirring power of the stirring rod were simulated based on CFD code. The numerical results show that the stirring temperature is lower, the shearing force is greater, the stirring time is longer, and particle dispersion gets better. On the other hand, the higher the stirring speed is, the more uniform the radial and axial flow are, and the better the particles were dispersed. The numerical results were in good agreement with the experimental data

Thermal fatigue crack behavior of SiCp/A356 composites prepared by stirring casting

The thermal fatigue crack initiation and propagation behavior of SiCp/A356 composites which is produced by stirring casting were studied. Specimens with a V-shaped notch were used in the thermal fatigue experiment. Optical microscope (OM) and scanning electron microscope (SEM) were used to observe the crack growth. Crack initiated at the notch tip after about 150 cycles of heating and cooling from room temperature to 250 °C. The crack propagation stage was dominated during the whole crack growth. Cracks mainly propagated along the interface of particle and through the matrix. The propagation stage experienced the cycle of slow propagation and fast propagation, and a Step-Like shape was observed during the crack growth process. The micro cracks appeared in the interface of particle and the matrix after repeated thermal cycles, and induced fast propagation by coalescing with the main cracks. Distributions of the particle play an important role in hindering thermal fatigue crack propagation. Hardness of the composites decreased with the increase of the number of cycles, and decreased by 46.1% after thermal 290 cycles. Keywords: SiCp/A356 composites, Thermal fatigue crack, Stirring casting, Crack propagation, Crack growt

Relationship between High Serum Cystatin C Levels and the Risk of Gestational Diabetes Mellitus.

AIMS:Serum cystatin C (CysC) has recently been shown to be associated with the incidence of type 2 diabetes mellitus (T2DM) and progression to the pre-diabetic state. The aim of this study was to explore the relationship between serum CysC and the risk of gestational diabetes mellitus (GDM) in Chinese pregnant women. METHODS:This cross-sectional study consisted of 400 pregnant women including 111 with GDM and 289 with normal glucose tolerance at 24-28 weeks of gestation. The subjects were further divided into four groups according to the CysC quartiles, and their clinical characteristics were compared. The serum CysC concentration was measured using immunoturbidimetry and the degree of insulin resistance was assessed by the homeostasis model assessment of insulin resistance (HOMA-IR). RESULTS:Serum CysC levels were significantly higher in pregnant women with GDM than in the healthy pregnant women[1.0(0.8-1.8) vs 0.7(0.6-1.0), P<0.01). The Spearman's correlation analysis showed that serum CysC was positively associated with HOMA-IR(r = 0.118, P<0.05) and the occurrence of GDM(r = 0.348, P<0.01). The pregnant women were divided into quartiles according to their serum CysC concentrations. Compared to the first quartile, pregnant women in Q2 (OR, 2.441; P = 0.025), Q3 (OR, 3.383; P = 0.001) and Q4 (OR, 5.516; P<0.001) had higher risk of GDM after adjusted for age, BMI, HbA1c and HOMA-IR. Further, with a rise in the serum CysC, there was an increasing trend in the HOMA-IR levels (P<0.05). A binary logistic regression analysis after adjusting for other confounding variables revealed a significant and independent association between serum CysC and GDM [OR = 14.269; 95% confidence interval, 4.977-40.908, P<0.01].The receiver operating characteristic curve analysis revealed that the optimal cutoff point for serum CysC to indicate GDM was 0.95 mg/L. CONCLUSIONS:Serum CysC is significantly and independently associated with insulin resistance and GDM. It may be a helpful biomarker to identify the risk of GDM in Chinese pregnant women

Heterogeneity of insulin resistance and beta cell dysfunction in gestational diabetes mellitus: a prospective cohort study of perinatal outcomes

Abstract Background Insulin resistance and beta cell dysfunction were reported to be responsible for gestational diabetes mellitus (GDM). However, little is known about the heterogeneity of these factors and its influences on perinatal outcomes. We investigated whether subtypes of insulin resistance and beta cell dysfunction in gestational diabetes mellitus have different impacts on perinatal outcomes. Methods In this prospective cohort study, we followed 554 pregnant women and glucose challenge test was performed at 24–28th weeks of their gestation. Women with plasma glucose ≥ 7.8 mmol/L would be included and advised to undergo the diagnostic 75-g, 3-h oral glucose tolerance test. According to indices of measuring insulin resistance or beta cell function were below the 25th percentile of women with normal glucose tolerance (NGT), women with GDM were defined as three subtypes: GDM with the beta cell dysfunction, GDM with the insulin resistance defect or GDM with both traits mentioned above (GDM-mixed). Perinatal outcomes were documented. Results The levels of prepregnancy and maternal BMI in the GDM-mix group were higher compared to women in the NGT group (23.2 ± 4.0 vs 20.8 ± 3.7 kg/m2, P < 0.001; 24.5 ± 4.3 vs 21.8 ± 3.4 kg/m2, P < 0.001, respectively). Furthermore, women in GDM-mix group more likely to be subjected to LGA (P = 0.008) adverse perinatal outcomes (P = 0.005), although these differences were normalized after adjusting age, prepregnancy and maternal BMI (GDM-mix vs. NGT: P = 0.141 for LGA and P = 0.186 for adverse outcomes). On the other hand, all perinatal outcomes were similar between other two GDM subgroups and NGT group. Conclusions Women with GDM display respective characteristics on metabolism disorders and confer discriminating risks of adverse perinatal outcomes because of this heterogeneity

Comparison of the clinical characteristics of GDM and healthy pregnant women.

<p>Comparison of the clinical characteristics of GDM and healthy pregnant women.</p