Fast identification of the charging pile plug materials using laser-induced breakdown spectroscopy

Lidan Chen; Tiantian Pan; Liuye Cao; Fei Liu

doi:10.1371/journal.pone.0342086

Peer Review History

Original SubmissionSeptember 10, 2025
29 Dec 2025 Decision Letter - Talaat Abdel Hamid, Editor PONE-D-25-49098Fast identification of the charging pile plug materials using laser-induced breakdown spectroscopyPLOS One Dear Dr. Pan, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Feb 12 2026 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Talaat Abdel Hamid, Ph.D Academic Editor PLOS One Journal requirements: When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Please note that PLOS One has specific guidelines on code sharing for submissions in which author-generated code underpins the findings in the manuscript. In these cases, we expect all author-generated code to be made available without restrictions upon publication of the work. Please review our guidelines at https://journals.plos.org/plosone/s/materials-and-software-sharing#loc-sharing-code and ensure that your code is shared in a way that follows best practice and facilitates reproducibility and reuse. 3. Thank you for stating the following in the Acknowledgments Section of your manuscript: “This study was supported by the Research Funding of Zhejiang Key Laboratory of Agricultural Remote Sensing and Information Technology” We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows: “The author(s) received no specific funding for this work.” Please include your amended statements within your cover letter; we will change the online submission form on your behalf. 4. We note that you have indicated that there are restrictions to data sharing for this study. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For more information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions. Before we proceed with your manuscript, please address the following prompts: a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially identifying or sensitive patient information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., a Research Ethics Committee or Institutional Review Board, etc.). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent. b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. For a list of recommended repositories, please see https://journals.plos.org/plosone/s/recommended-repositories. You also have the option of uploading the data as Supporting Information files, but we would recommend depositing data directly to a data repository if possible. We will update your Data Availability statement on your behalf to reflect the information you provide. 5. PLOS requires an ORCID iD for the corresponding author in Editorial Manager on papers submitted after December 6th, 2016. Please ensure that you have an ORCID iD and that it is validated in Editorial Manager. To do this, go to ‘Update my Information’ (in the upper left-hand corner of the main menu), and click on the Fetch/Validate link next to the ORCID field. This will take you to the ORCID site and allow you to create a new iD or authenticate a pre-existing iD in Editorial Manager. 6. Please amend either the abstract on the online submission form (via Edit Submission) or the abstract in the manuscript so that they are identical. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: No ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: Plasma condition clarification Although this study focuses on classification rather than quantitative analysis, a brief discussion of plasma stability or repeatability (e.g., justification of optimized laser energy and delay time in relation to plasma behaviour) would improve the physical completeness of the work. Self-absorption consideration Several strong Cu, Zn, and Te emission lines are used for feature extraction. A short statement discussing whether self-absorption effects are expected to be negligible under the selected experimental conditions would enhance the robustness of the interpretation. Model validation clarity The reported classification accuracies are very high, in several cases reaching 100%. Clarifying whether additional validation (e.g., repeated random splits or cross-validation) was tested, or adding a brief discussion on model generalizability, would strengthen the statistical interpretation without requiring major reanalysis. Data availability The Data Availability Statement currently indicates that the data are not available. To comply with PLOS ONE data policy, the authors should provide representative raw spectra or feature datasets as Supporting Information or through a public repository. Presentation improvements Minor improvements are recommended for figure clarity (axis labels, units) and correction of small grammatical or typographical issues throughout the manuscript. Overall Recommendation The manuscript is technically sound and addresses a relevant application of LIBS. The suggested revisions are minor and mainly intended to improve transparency, clarity, and compliance with journal policies. I therefore recommend minor revision. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: Yes: Ambreen Aslam ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] To ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation. NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications. https://doi.org/10.1371/journal.pone.0342086.r001
Revision 1
5 Jan 2026 Author Response Response to Reviews We thank reviewer for thoughtful and constructive comments on our manuscript. We greatly appreciate the time and effort you have dedicated to reviewing our work. Your detailed feedback has been incredibly helpful in improving the clarity and quality of our paper. We have carefully revised the manuscript, and we hope that the changes made address your concerns. Below, we provide a point-by-point response to your suggestions and questions. Reviewer #1: 1. Plasma condition clarification Although this study focuses on classification rather than quantitative analysis, a brief discussion of plasma stability or repeatability (e.g., justification of optimized laser energy and delay time in relation to plasma behaviour) would improve the physical completeness of the work. Response: Thanks for your insightful feedback. We have added the discussion of the effect of laser energy and delay time on plasma stability in Lines 202-218. At a moderate laser energy, the plasma temperature and electron density are optimized, allowing for the generation of sufficiently intense and stable signals. And a properly optimized delay time ensured that the plasma had reached a more stable phase where the signal intensity is sufficient, and the background noise is minimal, allowing for high-quality, reliable and stable signal collection. 2. Self-absorption consideration Several strong Cu, Zn, and Te emission lines are used for feature extraction. A short statement discussing whether self-absorption effects are expected to be negligible under the selected experimental conditions would enhance the robustness of the interpretation. Response: Thanks for your valuable suggestion. We have added the discussion on self-absorption effects in Lines 317-332. We have found that the Cu I 324.7537 nm and Cu I 327.3954 nm lines in all samples, and the Zn I 213.8573 line in brass samples were impacted by self-absorption due to their high concentration. While other weaker Cu and Zn lines, as well as the spectral lines associated with elements of low concentration (e.g., Te, Fe, Ni), were not notably impacted under the optimized experimental conditions. Despite this, the strong Cu I 324.7537 nm and Zn I 213.8573 nm lines were selected as features by both the CARS and SPA methods, and the models built using these features performed well. Given that the self-absorption effect on strong Cu lines affected all three kinds of samples, and the impact on strong Zn lines primarily affected brass samples, the overall influence of self-absorption on materials discrimination can be considered negligible. 3. Model validation clarity The reported classification accuracies are very high, in several cases reaching 100%. Clarifying whether additional validation (e.g., repeated random splits or cross-validation) was tested, or adding a brief discussion on model generalizability, would strengthen the statistical interpretation without requiring major reanalysis. Response: Thanks for your thoughtful feedback. The reported classification accuracies in the study are based on a single split of the data into training and test sets, without the use of additional validation techniques such as repeated random splits or cross-validation. We have also added the detail in Lines 152-153 and Lines 161-162. 4. Data availability The Data Availability Statement currently indicates that the data are not available. To comply with PLOS ONE data policy, the authors should provide representative raw spectra or feature datasets as Supporting Information or through a public repository. Response: Thanks for your valuable feedback. We have made the full spectra and feature datasets available through a public GitHub repository. The dataset and code can be accessed at the following link: https://github.com/ptthoshi-web/LIBS-Charging-pile-plug. We have updated Data Availability statement (Lines 380-381) as well. 5. Presentation improvements Minor improvements are recommended for figure clarity (axis labels, units) and correction of small grammatical or typographical issues throughout the manuscript. Response: Thanks for your kind suggestion. We have made the recommended minor improvements to the Fig. 2, 3, 4, and 6 for clarity. Additionally, we have carefully reviewed the manuscript and corrected the grammatical and typographical issues throughout (marked in blue). Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0342086.r002
19 Jan 2026 Decision Letter - Talaat Abdel Hamid, Editor Fast identification of the charging pile plug materials using laser-induced breakdown spectroscopy PONE-D-25-49098R1 Dear Dr. Pan, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Talaat Abdel Hamid, Ph.D Academic Editor PLOS One Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0342086.r003
Formally Accepted
Acceptance Letter - Talaat Abdel Hamid, Editor PONE-D-25-49098R1 PLOS One Dear Dr. Pan, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS One. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. You will receive an invoice from PLOS for your publication fee after your manuscript has reached the completed accept phase. If you receive an email requesting payment before acceptance or for any other service, this may be a phishing scheme. Learn how to identify phishing emails and protect your accounts at https://explore.plos.org/phishing. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Talaat Abdel Hamid Academic Editor PLOS One https://doi.org/10.1371/journal.pone.0342086.r004

Open letter on the publication of peer review reports

PLOS recognizes the benefits of transparency in the peer review process. Therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. Reviewers remain anonymous, unless they choose to reveal their names.

We encourage other journals to join us in this initiative. We hope that our action inspires the community, including researchers, research funders, and research institutions, to recognize the benefits of published peer review reports for all parts of the research system.

Learn more at ASAPbio .