Optimal power flow method with consideration of uncertainty sources of renewable energy and demand response

Optimal power flow (OPF) calculation methods are important for the power system operation and mainly focus on the deterministic power flow calculation, neglecting the impact of demand response on online security calculation of power systems with renewable energy sources. Therefore, this paper proposes an OPF calculation method that considers the uncertainties of wind power, photovoltaic (PV) power generation and demand-side response. Firstly, the research focuses on the renewable energy grid, considering the uncertainties of wind power and PV power generation, and establishes uncertainty models for wind power and PV output. Secondly, based on cloud model theory, an uncertainty model for demand response is established. According to the established models, an efficient OPF model is constructed with a linearized submodels considering multiple uncertainties. By testing on the IEEE 30-bus system as a typical example, we found the effectiveness and superiority of the proposed OPF calculation method can benefit the power system economic operation and demand side resource utilization

Pressure-induced superconductivity in quasi-one-dimensional semimetal Ta2PdSe6\mathrm{Ta}_2 \mathrm{PdSe}_6

Here we report the discovery of pressure-induced superconductivity in quasi-one-dimensional $\mathrm{Ta}_2 \mathrm{PdSe}_6$, through a combination of electrical transport, synchrotron x-ray diffraction, and theoretical calculations. Our transport measurements show that the superconductivity appears at a critical pressure $P_{\mathrm{c}} \sim 18.3$ GPa and is robust upon further compression up to $62.6$ GPa. The estimated upper critical field $\mu_0 H_{\mathrm{c} 2}(0)$ in the pressurized $\mathrm{Ta}_2 \mathrm{PdSe}_6$ is much lower than the Pauli limiting field, in contrast to the case in its isostructural analogs $M_2 \mathrm{Pd}_{\mathrm{x}} X_5$ $(M=\mathrm{Nb}$, Ta; $X=\mathrm{S}, \mathrm{Se})$. Concomitant with the occurrence of superconductivity, anomalies in pressuredependent transport properties are observed, including sign reversal of Hall coefficient, abnormally enhanced resistance, and dramatically suppressed magnetoresistance. Meanwhile, room-temperature synchrotron x-ray diffraction experiments reveal the stability of the pristine monoclinic structure (space group $C 2 / m$ ) upon compression. Combined with the density functional theory calculations, we argue that a pressure-induced Lifshitz transition could be the electronic origin of the emergent superconductivity in $\mathrm{Ta}_2 \mathrm{PdSe}_6$.Comment: 7 pages, 7 figure

Gastrodin ameliorates synaptic impairment, mitochondrial dysfunction and oxidative stress in N2a/APP cells

Alzheimer's disease is characterized by abnormal β-amyloid and tau accumulation, mitochondrial dysfunction, oxidative stress, and synaptic dysfunction. Here, we aimed to assess the mechanisms and signalling pathways in the neuroprotective effect of gastrodin, a phenolic glycoside, on murine neuroblastoma N2a cells expressing human Swedish mutant APP (N2a/APP). We found that gastrodin increased the levels of presynaptic-SNAP, synaptophysin, and postsynaptic-PSD95 and reduced phospho-tau Ser396, APP and Aβ1-42 levels in N2a/APP cells. Gastrodin treatment reduced reactive oxygen species generation, lipid peroxidation, mitochondrial fragmentation and DNA oxidation; restored mitochondrial membrane potential and intracellular ATP production. Upregulated phospho-GSK-3β and reduced phospho-ERK and phospho-JNK were involved in the protective effect of gastrodin. In conclusion, we demonstrated the neuroprotective effect of gastrodin in the N2a/APP cell line by ameliorating the impairment on synaptic and mitochondrial function, reducing tau phosphorylation, Aβ1-42 levels as well as reactive oxygen species generation. These results provide new mechanistic insights into the potential effect of gastrodin in the treatment of Alzheimer’s disease

Microstructure and damage tolerance properties in different directions of selective laser melted Al-Mg-Sc-Zr alloy

The microstructure，tensile and damage tolerance properties in different directions of Al-Mg-Sc-Zr alloy fabricated through selective laser melting（SLM）have been investigated. The results show that the YZ plane is a bimodal grain morphology composed of fine equiaxed grains and coarse columnar grains，while the XY plane is composed of fine equiaxed grains. The yield strength and tensile strength in both 0° and 90° directions are over 500 MPa，and the anisotropy is small，while the elongation in 90° direction is significantly lower than the 0° direction due to the lack of fusion（LOF）defects between the deposited layers. The KIC of the 0° and 90° CT samples are respectively 21.41 MPa·m1/2 and 20.89 MPa·m1/2. The resistance to crack propagation in columnar grains region is lower and leading to a smaller KIC for 90° CT samples. The microstructure and defects are the two main factors that affect the anisotropy of crack propagation performance. The LOF defects play a leading role in the near-threshold regime，and the crack propagation rate is faster when the crack propagation plane is parallel to transverse direction. On the other hand，the microstructure plays a leading role in the steady-state propagation regime. The fracture surface exhibits transgranular fracture when the crack propagation plane is parallel to transverse direction，which provides higher crack propagation resistance and result in lower crack propagation rate

Clustering and decision tree based analysis of typical operation modes of power systems

The increasing penetration of renewable energy resources has greatly changed the pattern of the modern power system. In this case, the operation modes of power systems are becoming much more complex and the traditional experience-based method is no longer practical in typical operation modes analysis. In this paper, a clustering and decision tree-based scheme is proposed for the analysis of the typical operation modes of power systems. Specifically, the k-means++ clustering algorithm is adopted to classify the operation data into different groups, which represent the typical operation modes. The group labels and several important operation features are used to construct a decision tree for the quantitative description of different kinds of typical operation modes. In addition, feature importance is analyzed and the decision tree is pruned with a balance between complexity and classification accuracy. Case studies are conducted based on the actual system planning data of the Jiangsu power grid to verify the effectiveness of the proposed scheme. From the results, system operators could get deep insights into system planning with a high share of renewable energy resources

Effects of cold air dehydration on icefish water dynamics and macromolecular oxidation measured by low-field nuclear magnetic resonance and magnetic resonance imaging

We have used low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging to measure water dynamics and migration, color, and texture profile (TPA) of icefish dried with hot and cold air methods. Relaxation time of T21, T22, and T23, and the peak area of A22 and A23 decreased significantly during drying. The water signal intensity decreased from the surface to inner regions during drying. Color parameters of L* and b* values increased significantly, TPA parameters of hardness increased, cohesiveness decreased significantly, and moisture content decreased significantly during drying. We observed correlations between the moisture content, TPA, color, and NMR parameters. In addition, we found lower thiobarbituric acid reactive substances and carbonyl content of the dried icefish with cold air compared with hot air. The cold air drying method yielded better sensory quality, and LF-NMR was a useful nondestructive method to determine the degree of drying and the quality of icefish

Extraocular muscle characteristics related to myasthenia gravis susceptibility.

BACKGROUND: The pathogenesis of extraocular muscle (EOM) weakness in myasthenia gravis might involve a mechanism specific to the EOM. The aim of this study was to investigate characteristics of the EOM related to its susceptibility to myasthenia gravis. METHODS: Female F344 rats and female Sprague-Dawley rats were assigned to experimental and control groups. The experimental group received injection with Ringer solution containing monoclonal antibody against the acetylcholine receptor (AChR), mAb35 (0.25 mg/kg), to induce experimental autoimmune myasthenia gravis, and the control group received injection with Ringer solution alone. Three muscles were analyzed: EOM, diaphragm, and tibialis anterior. Tissues were examined by light microscopy, fluorescence histochemistry, and transmission electron microscopy. Western blot analysis was used to assess marker expression and ELISA analysis was used to quantify creatine kinase levels. Microarray assay was conducted to detect differentially expressed genes. RESULTS: In the experimental group, the EOM showed a simpler neuromuscular junction (NMJ) structure compared to the other muscles; the NMJ had fewer synaptic folds, showed a lesser amount of AChR, and the endplate was wider compared to the other muscles. Results of microarray assay showed differential expression of 54 genes in the EOM between the experimental and control groups. CONCLUSION: Various EOM characteristics appear to be related to the increased susceptibility of the EOM and the mechanism of EOM weakness in myasthenia gravis