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Yinyu Zhang

Publications and source records attributed to Yinyu Zhang.

3 recordsLinked to original sources

Validity Verification of the New TOEFL Writing Task Based on Classical Test Theory

The TOEFL iBT has introduced the Academic Discussion Task (ADT) to assess test-takers' ability to engage in academic discourse, reflecting the growing emphasis on interactive communication skills in higher education. However, research on the ADT's validity and fairness particularly for culturally and linguistically diverse groups, such as Chinese students, remains limited. This study addresses this gap by employing Classical Test Theory (CTT) to evaluate the psychometric properties of the ADT among Chinese university students. This study finds a robust correlation between the ADT and the CET-6 writing and translation subscores. In addition, there is a high level of expert agreement regarding the construct validity evidence and the appropriateness of the scoring rubric. Furthermore, the results indicate that gender differences in validity indices are minimal. Taken together, these results suggest that the ADT is a valid measure for Chinese test-takers without gender discrimination. However, it is recommended that the cultural sensitivity of the scoring rubric be further refined and that the CET-6 subscores for writing be retained for predictive purposes, in order to better accommodate the needs of diverse test-taker populations. By addressing these issues, this study contributes to the broader discourse on fairness and validity in high-stakes language assessments.

cs.CY

Exploring Valence Electron Dynamics of Xenon through Laser-Induced Electron Diffraction

Strong-field ionization can induce electron motion in both the continuum and the valence shell of the parent ion. Here, we explore their interplay by studying laser-induced electron diffraction (LIED) patterns arising from interaction with the potentials of two-hole states of the xenon cation. The quantitative rescattering theory is used to calculate the corresponding photoelectron momentum distributions, providing evidence that the spin-orbit dynamics could be detected by LIED. We identify the contribution of these time-evolving hole states to the angular distribution of the rescattered electrons, particularly noting a distinct change along the backward scattering angles. We benchmark numerical results with experiments using ultrabroad and femtosecond laser pulses centered at \SI{3100}{nm}.

physics.atom-ph

Intensity-resolved measurement of above-threshold ionization of Ar-H$_2$O

Above-treshold ionization (ATI) by femtosecond laser pulses centered at 515\,nm is studied for a gas mixture containing the Van-der-Waals complex Ar-H$_2$O. By detecting photoions and -electrons in coincidence, the ATI spectra for Ar, Ar$_2$, \HHO, and Ar-\HHO are discerned and measured simultaneously. Using an intensity-scanning technique, we observe the red-shift of the ATI spectra as a function of the laser intensity. The intensity-dependent shift of the ATI peak positions observed for Ar-H$_2$O and H$_2$O match but significantly differ from the ones measured for Ar and Ar$_2$. This indicates that the photoelectron is emitted from the \HHO site of the complex and the vertical ionization potential of Ar-H$_2$O is determined as $(12.4 \pm 0.1)$\,eV. For resacttered electrons, however, an enhancement of high-order ATI is observed for Ar-H$_2$O, as compared to H$_2$O, suggesting that the relatively large Ar atom acts as a scattering center, which influences the ionization dynamics.

physics.atom-ph