In-orbit Measurement of Thermal Conductivity of Na 2 Mo 2 O 7 Melt under Microgravity Conditions on the China Space Station

In-orbit Measurement of Thermal Conductivity of Na 2 Mo 2 O 7 Melt under Microgravity Conditions on the China Space Station | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article In-orbit Measurement of Thermal Conductivity of Na 2 Mo 2 O 7 Melt under Microgravity Conditions on the China Space Station Huidong Li, Ye Tao, ChengCheng Cao, Qiu Zhong, Liping Yang, Xiuhong Pan, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9004697/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 29 Apr, 2026 Read the published version in International Journal of Thermophysics → Version 1 posted 11 You are reading this latest preprint version Abstract The growth of high-quality Na 2 Mo 2 O 7 single crystals, a promising scintillator material, is critically dependent on the precise knowledge of their melt's thermophysical properties. However, obtaining the intrinsic thermal conductivity of high-temperature melts is notoriously challenging on Earth due to buoyancy-driven convection. Here, we report the first direct measurement of the thermal conductivity of molten Na 2 Mo 2 O 7 , accomplished by employing a self-developed transient hot-wire system aboard the China Space Station. The microgravity environment effectively suppressed convection, enabling accurate measurement within the 750–900°C range. Results reveal that the intrinsic thermal conductivity decreases monotonically from approximately 0.457 W/(m·K) to 0.416 W/(m·K) with increasing temperature, a trend attributed to the phonon-dominated conduction mechanism. In contrast, terrestrial measurements yielded systematically higher values (by 12.0-16.6%) due to convective contributions. This work not only fills a critical data gap for optimizing crystal growth but also establishes a robust methodology for probing the thermophysical properties of high-temperature melts in space. microgravity thermal conductivity transient hot-wire method Na2Mo2O7 melt in-orbit measurement Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 29 Apr, 2026 Read the published version in International Journal of Thermophysics → Version 1 posted Editorial decision: Revision requested 22 Mar, 2026 Reviews received at journal 22 Mar, 2026 Reviews received at journal 19 Mar, 2026 Reviews received at journal 17 Mar, 2026 Reviewers agreed at journal 09 Mar, 2026 Reviewers agreed at journal 08 Mar, 2026 Reviewers agreed at journal 05 Mar, 2026 Reviewers invited by journal 03 Mar, 2026 Editor assigned by journal 03 Mar, 2026 Submission checks completed at journal 03 Mar, 2026 First submitted to journal 01 Mar, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9004697","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":601176521,"identity":"fad24c61-e0a6-4b2b-a84d-4fbb384c7c35","order_by":0,"name":"Huidong Li","email":"","orcid":"","institution":"Chinese Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Huidong","middleName":"","lastName":"Li","suffix":""},{"id":601176523,"identity":"cc375d91-31fd-41d1-8a76-7db3883d6396","order_by":1,"name":"Ye Tao","email":"","orcid":"","institution":"Chinese Academy of 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However, obtaining the intrinsic thermal conductivity of high-temperature melts is notoriously challenging on Earth due to buoyancy-driven convection. Here, we report the first direct measurement of the thermal conductivity of molten Na\u003csub\u003e2\u003c/sub\u003eMo\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e, accomplished by employing a self-developed transient hot-wire system aboard the China Space Station. The microgravity environment effectively suppressed convection, enabling accurate measurement within the 750\u0026ndash;900\u0026deg;C range. Results reveal that the intrinsic thermal conductivity decreases monotonically from approximately 0.457 W/(m\u0026middot;K) to 0.416 W/(m\u0026middot;K) with increasing temperature, a trend attributed to the phonon-dominated conduction mechanism. In contrast, terrestrial measurements yielded systematically higher values (by 12.0-16.6%) due to convective contributions. This work not only fills a critical data gap for optimizing crystal growth but also establishes a robust methodology for probing the thermophysical properties of high-temperature melts in space.\u003c/p\u003e","manuscriptTitle":"In-orbit Measurement of Thermal Conductivity of Na 2 Mo 2 O 7 Melt under Microgravity Conditions on the China Space Station","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-06 16:43:52","doi":"10.21203/rs.3.rs-9004697/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-22T11:22:18+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-22T11:11:32+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-19T21:42:59+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-17T16:46:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"12924040962065239769810602185207647689","date":"2026-03-09T23:45:55+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"256911964937457820560462548979084609759","date":"2026-03-08T13:38:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"41588470874980757840344248612233004400","date":"2026-03-05T10:42:23+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-03T21:55:15+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-03T05:44:49+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-03T05:43:54+00:00","index":"","fulltext":""},{"type":"submitted","content":"International Journal of Thermophysics","date":"2026-03-02T01:56:02+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"international-journal-of-thermophysics","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ijot","sideBox":"Learn more about [International Journal of Thermophysics](http://link.springer.com/journal/10765)","snPcode":"10765","submissionUrl":"https://submission.nature.com/new-submission/10765/3","title":"International Journal of Thermophysics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4d7bd09b-aa69-442f-a646-19cd9ee38e64","owner":[],"postedDate":"March 6th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-05-04T16:06:15+00:00","versionOfRecord":{"articleIdentity":"rs-9004697","link":"https://doi.org/10.1007/s10765-026-03764-0","journal":{"identity":"international-journal-of-thermophysics","isVorOnly":false,"title":"International Journal of Thermophysics"},"publishedOn":"2026-04-29 15:57:25","publishedOnDateReadable":"April 29th, 2026"},"versionCreatedAt":"2026-03-06 16:43:52","video":"","vorDoi":"10.1007/s10765-026-03764-0","vorDoiUrl":"https://doi.org/10.1007/s10765-026-03764-0","workflowStages":[]},"version":"v1","identity":"rs-9004697","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9004697","identity":"rs-9004697","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}