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Shaoheng Wang

Publications and source records attributed to Shaoheng Wang.

5 recordsLinked to original sources

LoRALib: A Standardized Benchmark for Evaluating LoRA-MoE Methods

As a parameter efficient fine-tuning (PEFT) method, low-rank adaptation (LoRA) can save significant costs in storage and computing, but its strong adaptability to a single task is often accompanied by insufficient cross-task generalization capabilities. To improve this, existing work combines LoRA with mixture-of-experts (MoE) to enhance the model's adaptability through expert modules and routing mechanisms. However, existing LoRA-MoE methods lack unified standards in models, datasets, hyperparameters, and evaluation methods, making it difficult to conduct fair comparisons between different methods. To this end, we proposed a unified benchmark named LoRALib. Specifically, we standardized datasets from $40$ downstream tasks into a unified format, fine-tuned them using the same hyperparameters and obtained $680$ LoRA modules across $17$ model architectures. Based on this LoRA library, we conduct large-scale experiments on $3$ representative LoRA-MoE methods and different LoRA selection mechanisms using the open-sourced testing tool OpenCompass. Extensive experiments show that LoRAMoE performs best, and that prioritizing LoRAs relevant to the target task can further improve the performance of MoE. We hope these findings will inspire future work. Our datasets and LoRA library are available at https://huggingface.co/datasets/YaoLuzjut/LoRAOcean_dataset and https://huggingface.co/YaoLuzjut/models.

cs.LG

Pressure Tuned 2D Superconductivity in Black Phosphorus

This paper examines the micro-parameters of superconductors. It studies the modulations from weak van der Waals interaction to strong covalence bonding of superconductors. In particular, we studied layered black phosphorus (BP) as a function of pressure. These results reveal a rich scenario of phase transitions and related quantum phenomena, which show that the phases exhibit superconducting states at a pressure higher than 5.0 GPa. In addition, they indicate an angle-dependent upper critical field that demonstrates the dimensional characteristics of superconductivities. This result suggests that the A17 and cubic phases are three-dimensional (3D). The A7 phase shows a two-dimensional (2D) character. The 2D behavior is related to a weakened, distorted, entangled interlayer coupling.

cond-mat.supr-con

The beam exchange of a circular cooler ring with a ultrafast harmonic kicker

In this paper, we describe a harmonic kicker system used in the beam exchange scheme for the Circulator Cooling Ring (CCR) of the Jefferson Lab Electron Ion Collider(JLEIC). By delivering an ultra-fast deflecting kick, a kicker directs electron bunches selectively in/out of the CCR without degrading the beam dynamics of the CCR optimized for ion beam cooling. We will discuss the design principle of the kicker system and demonstrate its performance with various numerical simulations. In particular, the degrading effects of realistic harmonic kicks on the beam dynamics, such as 3D kick field profiles interacting with the magnetized beam, is studied in detail with a scheme that keeps the cooling efficiency within allowable limits.

physics.acc-ph

Core-level x-ray photoemission and Raman spectroscopy studies on electronic structures in Mott-Hubbard type nickelate oxide NdNiO$_2$

We perform core-level X-ray photoemission spectroscopy (XPS) and electronic Raman scattering studies of electronic structures and spin fluctuations in the bulk samples of the nickelate oxide NdNiO$_2$. According to Nd $3d$ and O $1s$ XPS spectra, we conclude that NdNiO$_2$ has a large transfer energy. From the analysis of the main line of the Ni $2p_{3/2}$ XPS, we confirm the NiO$_2$ planes in NdNiO$_2$ are of Mott-Hubbard type in the Zaanen-Sawatzky-Allen scheme. The two-magnon peak in the Raman scattering provides direct evidence for the strong spin-fluctuation in NdNiO$_2$. The peak position determines the antiferromagnetic exchange $J=25$~meV. Our experimental results agree well with our previous theoretical results.

cond-mat.supr-con

Acceleration Modules in Linear Induction Accelerators

Linear Induction Accelerator (LIA) is a unique type of accelerator, which is capable to accelerate kiloAmpere charged particle current to tens of MeV energy. The present development of LIA in MHz busting mode and successful application into synchrotron broaden LIAs usage scope. Although transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. Authors examined the transition of the magnetic cores functions during LIA acceleration modules evolution, distinguished transformer type and transmission line type LIA acceleration modules, and reconsidered several related issues based on transmission line type LIA acceleration module. The clarified understanding should be helpful in the further development and design of the LIA acceleration modules.

physics.acc-ph