No abstract

We present measurements of the superconducting coherence length ξ in thin (d ≤ 100Å) films of MoGe alloy and Nb using a combination of linear and nonlinear mutual inductance techniques. As the alternating current in the drive coil is increased at fixed temperature, we see a crossover from linear to nonlinear coupling to the pickup coil, consistent with the unbinding of vortex-antivortex pairs as the peak pair momentum nearsh/ξ and the unbinding barrier vanishes. We compare measurements of ξ made by this mutual inductance technique to values determined from the films' upper critical fields, thereby confirming the applicability of a recent calculation of the upper limit on a vortex-free state in our experiment.

Achievement in school is crucial for students to be able to pursue successful careers and lead happy lives in the future. Although many psychological attributes have been found to be associated with academic performance, the neural substrates of academic performance remain largely unknown. Here, we investigated the relationship between brain structure and academic performance in a large sample of high school students via structural magnetic resonance imaging (S-MRI) using voxel-based morphometry (VBM) approach. The whole-brain regression analyses showed that higher academic performance was related to greater regional gray matter density (rGMD) of the left dorsolateral prefrontal cortex (DLPFC), which is considered a neural center at the intersection of cognitive and noncognitive functions. Furthermore, mediation analyses suggested that general intelligence partially mediated the impact of the left DLPFC density on academic performance. These results persisted even after adjusting for the effect of family socioeconomic status (SES). In short, our findings reveal a potential neuroanatomical marker for academic performance and highlight the role of general intelligence in explaining the relationship between brain structure and academic performance.Academic performance at the end of high school plays a crucial role in students' future academics and career development. For instance, in China, the score of the Chinese National College Entrance Examination (CNCEE) (also known as Gaokao) taken at the end of high school is the sole criterion for admission to Chinese universities. Success in this examination offers not only a key opportunity for students to acquire subsequent academic and vocational achievement but also represents a critical promising opportunity for poverty-stricken families to change their fortunes 1, 2 . Therefore, exploring the factors related to academic performance in adolescents at the end of high school might be critical for possible reforms in education and curriculum.Evidence from numerous studies has showed that a myriad of psychosocial factors contribute to academic performance 3 , which is usually measured by standardized tests (e.g., the Achievement College Test and the Stanford Achievement Test) or Grade Point Average (GPA) 4, 5 . Among these factors, general intelligence is the most stable and powerful predictor of academic performance 6,7 . The mean correlation between general intelligence and academic performance is approximately 0.5 8, 9 , which varies considerably depending on the variability of the measures and samples. Furthermore, several studies have shown that general intelligence plays a causal role in academic performance [10][11][12][13] . In this research, we sought to explore the neuroanatomical correlates of academic performance and the role of general intelligence in the association between brain anatomy and academic performance by performing structural magnetic resonance imaging (S-MRI).Although academic performance is a popular research topic in the fields of psychology a...

It is inevitable for power transformers to suffer from multiple impacts of short-circuit (SC) current and huge dynamic electromagnetic force in service which may cause large elastic and plastic deformations. Under the SC fault, the distribution of flux leakage and the amplitude of electromagnetic force may be disturbed by winding deformations or displacement. This paper analyzes the cumulative strain-stress characteristics of transformer windings using coupled electromagneticstructural analysis solution. The dynamic electromagnetic force, mechanical stress, and plastic deformation are calculated by 3-D finite element method (FEM). An example of two-winding, 110kV transformer is simulated. It is found that an initial and little deformation in windings may influence the magnetic flux distribution. The changed flux density may enlarge the applied electromagnetic force in the windings. The cumulative model and simulation results of this paper may be useful for investigating the winding deformation state prediction.  Index Terms-transformer winding; magnetic-structural coupling; short-circuit force; cumulative deformation; finite element method.

Abstract-Through exploring the relationship between the Q-factor and the normalized electric field strength of a reverberation chamber, this contribution proposes a new kind of methods for the Q-factor estimation, which can simplify the procedure of measuring Q-factor in experiment and raise the efficiency of calculating Q-factor by simulation. Firstly, the method is validated using measured electric field, then it is verified using data from RC's simulation by FDTD. Satisfactory agreements confirm this kind of methods could act as a reliable tool in estimating Q-factor by both experimental measurement and numerical simulation.