Effects of the α\alpha-cluster structure and the intrinsic momentum component of nuclei on the longitudinal asymmetry in relativistic heavy-ion collisions

The longitudinal asymmetry in relativistic heavy-ion collisions arises from the fluctuation in the number of participating nucleons. This asymmetry causes a rapidity shift in the center of mass of the participant zone. Both the rapidity shift and the longitudinal asymmetry have been found to be significant at the top LHC energy for collisions of identical nuclei. However, much discussion of the longitudinal asymmetry has treated the initial condition as a non-zero momentum only contributed only by the number of participants, i.e., the asymmetry depends only on the number of participating nucleons. In this work, we consider other effects on the longitudinal asymmetry other than fluctuation in the number of participants, e.g. the intrinsic momentum distribution as well as $\alpha$-clustering structure in the target or projectile nuclei for the collisions in the framework of a multiphase transport (AMPT) model. By introducing systems with different $\alpha$-clustering structure and intrinsic momentum distribution, we calculated ratio of different systems' rapidity distribution and extracted expansion coefficient to analyze the difference contributed by these factors. And we investigated the possible effect of non-Gaussian distribution on the rapidity distribution. These results may help us to constrain the initial conditions in ultra-relativistic heavy-ion collisions, and suggest a quantitative correction on final state measurement and a possible correlation between the initial condition and the final-state observable in LHC and RHIC energy.Comment: 10 pages, 5 figure

LLM-FuncMapper: Function Identification for Interpreting Complex Clauses in Building Codes via LLM

As a vital stage of automated rule checking (ARC), rule interpretation of regulatory texts requires considerable effort. However, interpreting regulatory clauses with implicit properties or complex computational logic is still challenging due to the lack of domain knowledge and limited expressibility of conventional logic representations. Thus, LLM-FuncMapper, an approach to identifying predefined functions needed to interpret various regulatory clauses based on the large language model (LLM), is proposed. First, by systematically analysis of building codes, a series of atomic functions are defined to capture shared computational logics of implicit properties and complex constraints, creating a database of common blocks for interpreting regulatory clauses. Then, a prompt template with the chain of thought is developed and further enhanced with a classification-based tuning strategy, to enable common LLMs for effective function identification. Finally, the proposed approach is validated with statistical analysis, experiments, and proof of concept. Statistical analysis reveals a long-tail distribution and high expressibility of the developed function database, with which almost 100% of computer-processible clauses can be interpreted and represented as computer-executable codes. Experiments show that LLM-FuncMapper achieve promising results in identifying relevant predefined functions for rule interpretation. Further proof of concept in automated rule interpretation also demonstrates the possibility of LLM-FuncMapper in interpreting complex regulatory clauses. To the best of our knowledge, this study is the first attempt to introduce LLM for understanding and interpreting complex regulatory clauses, which may shed light on further adoption of LLM in the construction domain

An Improved Direct Torque Control for a Single-Winding Bearingless Switched Reluctance Motor

The direct torque control (DTC) and direct force control (DFC) method were introduced to reduce the torque and levitation force ripple in single-winding bearingless switched reluctance motors (SWBSRMs). However, it still has some disadvantages. Firstly, the flux-linkage control is not suitable for the DTC method in SWBSRMs. On the one hand, it can increase the torque ripple. On the other hand, the RMS current can be increased and then the torque-ampere ratio is decreased. Secondly, the vectors selection is also unreasonable, which can increase the torque ripple further. In order to solve these problems, an improved control method based on DTC and DFC method for SWBSRMs is proposed in this paper, which can obtain high torque-ampere ratio and low torque ripple simultaneously. In the proposed method, the flux-linkage loop control is not needed and the space voltage vector table is improved. The experimental results show that the torque ripple is reduced by 66.7%, the torque-ampere ratio is increased by 200% and the switching times in one electrical period are reduced by 47.3%