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Load prediction of power system plays an important role in real-time control and ensuring economic, safe and reliable operation of power system. At the same time, the variation of power load system parameters is affected by many factors, which will lead to the nonlinear development of load curve. In this paper, a prediction method based on BP neural network is proposed. The biggest advantage of this method is that it has adaptive function to a large number of nonlinear characteristics and non-accuracy laws. This paper mainly focuses on the application of BP neural network in short-term load prediction of power system to do further research, and through MATLAB BP neural network design, simulation results show that the application of BP neural network in short-term load prediction is feasible, can better reflect the nonlinear characteristics of load prediction. However, because this paper does not consider the effects of climate, temperature, holidays and other factors, there is still a certain gap between the simulation results and the ideal results, but it is certain that BP neural network is still better than the traditional prediction method, is a very promising new research and development field.

Bis (2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) is an extensively used novel brominated flame retardant that is present ubiquitously in the environment and in biota. However, there is inadequate data on its potential hepatotoxicity to humans. In this study, high-coverage quantitative metabolomics based on

In today’s increasingly frequent international exchanges, language ability has been paid more and more attention. However, the current foreign language teaching in some areas lacks a standard external input environment, and the gap between learners’ own ability and the new requirements has not been effectively solved. At present, intelligent speech synthesis technology is mature. It is found that this technology can play a unique advantage in language teaching. Based on this, this study studies the feasibility of the application of intelligent speech synthesis technology in foreign language teaching from the perspective of technology. On this basis, the application mode of intelligent speech synthesis technology in foreign language teaching is constructed to verify its application effect in foreign language teaching. The main research work of this paper is as follows: firstly, it analyzes the feasibility of using clever speech synthesis technologies to teach foreign languages, and it lists in detail the application conditions of intelligent speech synthesis technology in different teaching activities and course types. Then, it constructs the application mode of intelligent speech synthesis technology in foreign language teaching. Finally, the experimental research on the application mode of intelligent speech synthesis technology in listening teaching is carried out. The experimental results show that intelligent speech synthesis technology has achieved good results in foreign language teaching and laid a foundation for foreign language teaching research.

Due to the depletion of traditional Chinese renewable energy sources such as crude oil, increased pollution and the endogenous transformation and upgrading of China's economy and society, the flourishing of China's new energy vehicle business is an inevitable requirement for a flourishing low-carbon and green economy. In the context of the global green transformation and the new double-cycle economic development, the flourishing of the new energy vehicle industry is an inevitable requirement for the development of a low-carbon and green economy, and is a necessary path for China to move from a large automotive nation to a strong automotive nation. China's new energy vehicle exports are growing steadily, mainly to Asian and European markets, especially Europe, where a major breakthrough has been made, mainly in the export of pure electric passenger cars and the rise of independent brands. The dividends from new energy vehicles are being used not only for international foreign trade, but also for road dust protection and landmark maintenance.

The occurrence of extreme weather events will cause serious harm to natural ecosystems, human social economy and construction sites. Large-scale construction projects have a long cycle and complex construction environment, and the schedule control is obviously disturbed by meteorological and other factors. Risk control of schedule delays is an important part of project risk management. The study of extreme weather events has become a key focus and hotspot in meteorological and climate science research in the context of global change. This paper proposes a more objective approach to defining extreme climate events from the study of extreme climate event uncertainty. On this basis, the spatial and temporal characteristics of extreme temperature and precipitation in recent decades are analysed. Considering the variability of precipitation and temperature, an idea is proposed to study extreme continuous precipitation events, and the mechanism of extreme precipitation occurrence in the region is explored. Finally, the LSTM model data are used to carry out studies and projections of changes in extreme climate events under different future scenarios.

Today, with the improvement of social productivity, the quality of life of our residents has been unprecedentedly improved, but the problems of uncoordinated, insufficient and unsustainable development still exist, such as the environmental problems closely related to people's lives. In recent years, sandstorms, automobile exhaust, industrial and agricultural smoke and dust, construction dust and other haze caused by the haze, has seriously affected the normal life of the people, the normal production of society, the health of residents; among them, construction dust, is gradually becoming the leading factor leading to air quality pollution, but as long as the right measures, construction work construction. The first convenient installation, saving time for installation and later disassembly, the second convenient device disassembly and handling effect, at the same time sealing snap post and sealing snap slot snap, complete the sealing fit of the two wind protection plate, increase the sealing of the device, so as to improve the device wind protection effect and improve the overall practicality of the device.

For the unmanned vehicle, multi-line LiDAR (Light Detection and Ranging) and GPS/IMU are often used in conjunction for SLAM or the production of high-precision maps. To improve the accuracy of navigation as well as map building, the extrinsic parameters calibration of LiDAR and GPS/IMU is often required. In response to the problem of insufficient conditions in the calibration of LiDAR and GPS/IMU for unmanned vehicle, this paper proposes a decoupling method, grouping the extrinsic parameters for calibration, and finally merges the point clouds with the pose obtained by the GPS/IMU before and after calibration to get environment reconstruction results. With the reconstruction results before and after calibration, it is verified that the method proposed is effective.

A tightly coupled LIDAR-IMU SLAM is proposed in this paper to make precise and robust estimation on position, posture, velocity as well as bias of accelerometers and gyros in off-road environment where features are not sufficient. This method is based on optimization of residuals both produced by LIDAR point clouds and IMU integration. The first part of residuals comes from the sum of distance between current sweep point clouds and voxel centroid of relative maps which are built simultaneously. The second part of residuals comes from a pre-integration procedure which takes LIDAR and IMU calibration error into account. A series of experiments based on data collected from an intelligent vehicle platform is carried out to evaluate the SLAM system. The experimental results have proven the ability of the system for precise pose estimation. Compared with the LIDAR-only method, LIDAR-IMU SLAM shows better performance on the estimation accuracy and robustness on position and posture as well as obtaining convergent result of pitch and roll angle.

Compared to conventional MS and NMR techniques, high-performance chemical isotope labeling (CIL) LC-MS provides accurate relative quantification of many more metabolites in biological samples. However, to apply this technique for urine and fecal metabolomics studies of animal models, the entire workflow, including the preanalytical process, needs to be strictly controlled to avoid or minimize quantitative errors. In this study, we report our investigation of the effects of mouse urine and fecal sample collection methods on CIL LC-MS metabolome analysis. Metabolic-cage collection and spot-sample collection of urine and feces were compared in a mouse model of CCl

To establish a method for simultaneous determination of chlorfenapyr and indoxacarb in tea by gas chromatography-mass spectrometry.The tea samples were homogenized and extracted with acetonitrile. Extracts obtained through centrifugation were cleaned up by CARB / NH2 cartridges, and further purified with SLH cartridges. After separated by DB-5MS capillary column( 30 m × 0. 25 mm × 0. 25μm), the analytes were measured by gas chromatography-mass spectrometry in selective ion monitoring( SIM) mode and quantified by external standard method.The linear range was 0. 10- 10 μg / m L for both of the two pesticides. The detection limits of chlorfenapyr and indoxacarb in tea samples were 0. 01 and 0. 008 mg / kg, and the quantitation limits were 0. 03 and 0. 025 mg / kg, respectively. The recoveries were from75. 6% to 92. 7%, and the relative standarddeviations( RSDs) were 3. 6%- 11. 4%( n =6).The proposed method has good purification effect and high accuracy, which is capable for simultaneously detecting the chlorfenapyr and indoxacarb in tea samples.

To establish a method for determination of 16 polycyclic aromatic hydrocarbons( PAHs) in edible oils by gas chromatography-mass spectrometry( GC/MS) combined with molecularly imprinted solid phase extraction( MISPE-GC/MS).Oil samples were diluted with n-hexane, purified by SPE cartridges based on molecularly imprinted polymer. The cartridges were washed by n-hexane to remove impurities, then eluted with dichloromethane. After being concentrated to a volume of 200μL, the analytes were separated by capillary column( 30 m×0. 25 mm×0. 25 μm) and analyzed by GC/MS with selected ion monitoring( SIM) mode. Isotope internal standard method was adopted for quantification.The 16 kinds of PAHs showed good linearity in the range of 2-20 μg/L( r0. 998). The detection limits ranged from 0. 1 to0. 6 μg/kg. The recoveries of spiked samples at the level of 2 μg/kg and 10 μg/kg were in the range of 75. 5%-125. 2%( n = 6), the relative standard deviations( RSD) were all less than 15%.The proposed method is selective, fast, and presentsexcellent purification effect as well as high sensitivity, which makes it capable for rapid determination of 16 PAHs in edible oils with satisfactory accuracy.

There are many freeware or shareware applications for solving data envelopment analysis (DEA), but these are not easy to understand and because of theoretical difficulties, are not efficient at understanding and analyzing DEA. Excel Solver, a add-in for Microsoft Excel is suggested for solving DEA and also a comprehensive method for solving DEA problems is proposed.

This article deals with Theory of Constraints (TOC) project scheduling with fuzzy processing time. Firstly the ambiguous processing time was formulated using the fuzzy possibility function. Next the agreement index between managers and decisionmakers was calculated in order to establish ideas common to both. A method is proposed for transforming the agreement index into actual processing time and the validity of this method is analyzed.

Multifunctional nanoparticles integrated with an imaging module and therapeutic drugs are promising candidates for future cancer diagnosis and therapy. Mesoporous silica coated gold nanorods (AuNR@MS) have emerged as a novel multifunctional cancer theranostic platform combining the large specific surface area of mesoporous silica, which guarantees a high drug payload, and the photothermal modality of AuNRs. However, premature release and side effects of exogenous stimulus still hinder the further application of AuNR@MS. To address these issues, herein, we proposed a glutathione (GSH)-responsive multifunctional AuNR@MS nanocarrier with in situ formed silver nanoparticles (AgNPs) as the capping agent. The inner AuNR core functions as a hyperthermia agent, while the outer mesoporous silica shell exhibits the potential to allow a high drug payload, thus posing itself as an effective drug carrier. With the incorporation of targeting aptamers, the constructed nanocarriers show drug release in accordance with an intracellular GSH level with maximum drug release into tumors and minimum systemic release in the blood. Meanwhile, the photothermal effect of the AuNRs upon application to near-infrared (NIR) light led to a rapid rise in the local temperature, resulting in an enhanced cell cytotoxicity. Such a versatile theranostic system as AuNR@MS@AgNPs is expected to have a wide biomedical application and may be particularly useful for cancer therapy.

We propose the problems of multiple Decision Maker(DM)s' consensus building in this paper. The problems are classified two models from viewpoints of decision makers' pattern. First model has Super Decision Maker(SDM) and DMs. Second Model has only DMs. The former model with SDM and DMs is corresponded to the traditional Analytic Hierarchy Process(AHP) model which can be solved the AHP method. The former model with SDM and DMs is also called the Group-AHP model. The latter model called group-DEAHP with only DMs is solved by the Data Envelopment Analysis(DEA). This paper focus on latter model, the efficient solution procedure is proposed based on the grey system theory.

In-plane macrocrack initiation of as-deposited, thermally aged, and in-service used thermal barrier coatings (TBCs) with different levels of pores and microcracks, affecting the Young’s modulus (E c ), have been studied using a newly developed protruded TBC bending technique in conjunction with a finite-element stress analysis. In-plane macrocracking along splat boundaries initiates from a curved edge of protruded TBC under the out-of-plane and shear applied and residual stresses resolved from the in-plane components. The TBC macrocracking is characterized by the critical strain energy density [(σ * )2/E c ], which represents the material propensity, i.e., the ratio of the interfacial cohesive energy to the critical microcrack size (γ f /a c ), and the residual stress effect. The cracking behavior strongly depends on the type of TBC, subjected to different thermal history, and the substrate machining. Ungrooved substrate specimen tests indicate that while the as-deposited TBC has through-thickness fluctuation in (σ * )2/E c , the aged and used TBC exhibits a trough and peak of (σ * )2/E c near the middle section, respectively. In grooved or thinner substrate specimens of the TBCs where the residual stress is partially relieved, cracking further away from the interface occurs at lower and constant (σ * )2/E c representing γ f /a c . It is interpreted that the through-thickness variations of (σ * )2/E c in the ungrooved substrate specimen of the various TBCs are more largely affected by the out-of-plane compressive residual stress than γ f /a c .

The effect of anisotropic microstructure of a two-dimensional periodic composite on the optical nonlinearity enhancement of the bulk material is investigated. The calculations are based on Stroud–Hui expression for effective third-order nonlinear susceptibility χe and the series expressions of space dependent electric field and/or electric displacement in periodic composite obtained by a simple Fourier approach. The frequency dependences of χe and effective dielectric function ee for the anisotropic composites with metallic elliptic inclusions in an insulating host have been evaluated. The results indicate that for geometric anisotropic composites, the positions of the absorption and nonlinearity enhancement are very close, not separate. When the morphology of inclusions varies, the variation tendencies of strengths of the absorption and nonlinearity enhancement are opposite. With the shape variation of elliptic inclusions from prolate to oblate, the nonlinearity enhancement increases while the absorption decreases.

We adopt B-spline finite basic sets to calculate correlation energy of the ground states for five kinds double-electron atoms or ions, which is above 1st order of magnitude better than the standard configuration-interaction (CI) method and modified configuration-interaction (MCI) method. These results show its superiority when we use it to deal with the problems of atom structure.

Fatigue crack growth along an Al/epoxy interface was examined under different combinations of mode-I and mode-II loadings using the flexural peel technique. Fatigue crack growth rates were obtained as a function of the total strain energy rate for GII/GI ratios of 0.3 to 1.4, achieved by varying the relative thickness of the outerlayers for the flexural peel specimen. Fatigue crack growth resistance of the interface was found to increase with increasing GII/GI ratio. Such a shear-enhanced crack growth resistance of the interface resulted in a gradual transition of crack growth mechanism from interfacial at the low GII/GI ratio to cohesive at the high GII/GI ratio. Under predominantly mode-I loading, the damage in the polymer took the form of crazing and cavitation. In contrast, laminar shear occurred under highly shear loading, resulting in a larger amount of plastic dissipation at the crack tip and improved fatigue crack growth resistance.

A flexural peel (FP) technique was developed to study the crack growth behavior along a bimaterial interface. The technique was based on a sandwich specimen where one arm of the specimen was peeled away from the interface under a combined tensile and shear mode. An approximate linear elastic fracture mechanics solution was derived analytically from theJ integral formulation. The solution was compared to finite element calculations based on the crack closure method and experimental measurements. From the finite element analysis, ratios of the mode-I and mode-II components of the crack tip field were determined for a wide range of modulus and thickness ratios.

A new backface strain technique was developed to detect fatigue crack initiation in adhesive-bonded lap joints. The technique was based on the special strain distribution in single lap joints and detected the fatigue crack initiation by the switch in the direction of the strain variation. Use of this technique not only permits the determination of fatigue crack initiation life in the joint, but also allows the site of crack initiation to be located. With the assistance of this new backface strain technique, a fatigue crack was found to initiate in the adhesive but to propagate towards the interface to continue its growth on the interface and to cause the final separation of the joint along the interface. Measurements of fatigue crack initiation lives at different stress levels indicate that the adhesive-controlled crack initiation took an increasingly greater proportion of the total fatigue life as the stress decreased, so that the lifetime in the long-life regime was dominated by the resistance ...

The role of interfacial microstructure in the fracture of particulate reinforced metal matrix composites was examined in a cast Al 2 O 3 /AlCu composite, heat-treated to different aging conditions. It was found that the composite has a high plane strain fracture toughness in the peak-aged condition and the toughness decreases with decreasing yield strength following high temperature overaging of the composite. Interfacial studies have shown that the high fracture toughness is related to the beneficial role of a soft interfacial layer, which permits the ductility of the matrix to be fully realized during fracture. When such a compliant interfacial layer is removed, e.g. by extended overaging, a significant drop in fracture toughness was observed. Based on experimental observations and micromechanical modelling, it was shown that the variation of fracture toughness with aging condition is consistent with the transition of fracture mechanism from near-interface failure to interfacial failure.

The energy spectra and oscillator strength of atom Rb in strong magnetic fields are calculated. The wavefunctions obtained by an improved potential model proposed by some of us are chosen as the zero-order ones. The results show that the diamagnetic term seems to affect substantially only high Rydberg states. And there is a maximum of oscillator strength in each n-manifold, which varies with n increased.

The vibrational densities of states for an octagonal quasiperiodic lattice are calculated. Crossovers from phonon excitations to fracton-like excitations are found in the low-frequency parts of the spectra (this part is referred to as the continuous spectrum); meanwhile, localized vibrational modes are observed in the high-frequency parts (this part is referred to as the characteristic spectrum). The spectral features are governed by alpha and beta, the central and non-central force constants of the Born model. For the low-frequency continuous spectrum, when alpha/beta equals unity (isotropic model) and when alpha/beta is not very large, a power law is satisfied in the fracton-like excitation frequency regime but, when alpha/beta approaches infinity, the spectrum deviates from the original power law. For the high-frequency characteristic spectrum, in an isotropic situation, i.e. in the case when alpha/beta = 1, the localized mode is isolated and a gap separates it from other modes but, when there is no longer isotropy, the gap disappears.

A method suitable for two-electron systems in a range running from low to high fields is given. M-L = -1 triplet state of H- ion and He atom are used to introduce the new means. All the matrix elements in our calculations are formulated as products of simple, independent one-dimensional numerical integrals and analytic ones. As a result, lower energies compared to those obtained with spherical coordinates in low fields, and cylindrical coordinates in high fields are presented.

Stoichiometric intermetallic compounds have always been touted for their attractive chemical, physical, electrical, magnetic and mechanical properties, but few practical uses have materialized because they are brittle at room temperature1,2,3,4. Here we report on a large family of fully ordered, stoichiometric binary rare-earth intermetallic compounds with high ductility at room temperature. Although conventional wisdom calls for special conditions, such as non-stoichiometry, metastable disorder or doping to achieve some ductility in intermetallic compounds at room temperature, none of these is required in these unique B2 rare-earth compounds. Ab initio calculations of YAg, YCu and NiAl crystal defect energies support the observed deformation modes of these intermetallics.