A number of areal surface texture parameters have been adopted by standards bodies, namely ISO 25178-2, in which forty-one parameters within six groups are defined. The selection of the suitable areal parameters becomes an issue for a designer. The study of correlation among parameters is one of the ways to find the most suitable parameters for a specification. This paper presents a Spearman's correlation study of areal surface texture parameters on some typical machined surfaces. Sixty surfaces, produced by nineteen machining methods, have been assessed by the use of an optical instrument; the operators adhered to ISO 25178-3; and parameters defined by ISO 25178-2. The correlation results are classified by using five correlation levels. It details the correlations between different groups of parameters, together with the correlation of parameters within the same group. The results are presented in Spearman's rank correlation coefficient matrix and charts. A three-layer parameters tree is then proposed to help engineer in the selection of parameters

Representing the semantics of the interaction of two or more tolerances (i.e., composite tolerance) explicitly to make them computer-understandable is currently a challenging task in computer-aided tolerancing (CAT). We have proposed a description logic (DL) ontology-based approach to complete this task recently. In this paper, the representation of the semantics of the composite positional tolerance (CPT) for patterns of holes (POHs) is used as an example to illustrate the proposed approach. This representation mainly includes representing the structure knowledge of the CPT for POHs in DL terminological axioms; expressing the constraint knowledge with Horn rules; and describing the individual knowledge using DL assertional axioms. By implementing the representation with the web ontology language (OWL) and the semantic web rule language (SWRL), a CPT ontology is developed. This ontology has explicitly computer-understandable semantics due to the logic-based semantics of OWL and SWRL. As is illustrated by an engineering example, such semantics makes it possible to automatically check the consistency, reason out the new knowledge, and implement the semantic interoperability of CPT information. Benefiting from this, the ontology provides a semantic enrichment model for the CPT information extracted from CAD/CAM systems.

This article aims to complete a review of current literature describing the measurement and characterization of photoelectric and geometric properties of perovskite solar cell (PSC) film layer materials using the spectroscopic ellipsometry (SE) measurement technique. Firstly, the influence of film quality on the performance of PSCs is combed and analyzed. Secondly, SE measurement technology is systematically introduced, including the measurement principle and data analysis. Thirdly, a detailed summary is provided regarding the characterization of the geometric and optoelectronic properties of the substrate, electron transport layer (ETL), perovskite layer, hole transport layer (HTL), and metal electrode layer using SE. The oscillator models commonly used in fitting film layer materials in PSCs are comprehensively summarized. Fourthly, the application of SE combined with various measurement techniques to assess the properties of film layer materials in PSCs is presented. Finally, the noteworthy direction of SE measurement technology in the development of PSCs is discussed. The review serves as a valuable reference for further enhancing the application of SE in PSCs, ultimately contributing to the commercialization of PSCs.

The straightness and flatness errors are generally assessed by using the Least Squares Method (LSM). However, the results obtained from LSM often overestimate the tolerances, and are not consistent with the ISO standards’ definitions. To this end, this paper presents a method to evaluate those errors by using particle swarm optimization (PSO). The realization technique is detailed. The experimental data is utilized to verify this algorithm, together with a comparison with some typical optimization algorithms