Abstract
While mobile technology is rapidly evolving, it remains a challenge for some older adults to use smartphones worldwide. To address this issue through tailored skill training and product design, this study developed a questionnaire to assess the smartphone proficiency of older adults. The Smartphone Proficiency Questionnaire for Chinese Older Adults (SPQ-COA) assessed proficiency based on 30 up-to-date tasks (e.g., mobile payment), that covered common operations in daily life of Chinese older adults. The questionnaire was distributed to 452 older adults (age ≥60), as well as 100 young adults (age: 18–30) as a control group. The questionnaire performed well in terms of reliability, difficulty, and discrimination. Among older adults, higher scores were associated with lower age, longer daily use duration, more years of use, higher monthly income, and higher education level, further validating the questionnaire. Overall, the SPQ-COA is a valid tool for evaluating Chinese older adults’ smartphone usage skills.
Keywords
• Based on recent statistical reports, we updated the function set commonly used on smartphones. • We developed a regionally-optimized smartphone proficiency measurement tool for Chinese older adults. • We identified predictors of older adults’ smartphone proficiency, promoting aging-friendly research.
• This questionnaire can measure the smartphone proficiency of Chinese older adults, and the predictors of proficiency level can inform tailored skill training and user experience design for older adults. • The pattern of proficiency provides insights for developing supportive policies to enhance digital literacy among older adults, helping them bridge the digital divide. • The questionnaire covered the functions that represent growing mobile trends globally, thus can guide tool development for older adults in other countries as well.What this paper adds
Applications of study findings
Introduction
Usage of Smartphones in Older Adults
With the development of Internet technology, our reliance on the Internet have pervaded daily communication, education, entertainment, etc. As of December 2022, China’s Internet penetration rate had reached 75.6%, and the size of Internet users reached 1.067 billion (CINIC , 2023). Notably, the proportion of Internet users among older adults burgeoned from 16.7% to 54.5% between 2017 and 2022 (CINIC, 2018; CINIC, 2023; MOCA, PRC, 2023). When it comes to the medium of Internet access, China Internet Network Information Center (CINIC, 2022) released that 99.5% of Chinese older adult Internet users accessed the Internet through smartphones, basically the same as the situation of overall proportion of Internet users (99.8%), while the number of people using computers to access the Internet is declining year by year. As a result of this, the smartphone usage situation of older adults in China can be mirrored by their Internet usage situation. This situation is predictable because mobile devices such as smartphones are more prevalent compared with computers and can provide older individuals with an accessible gateway to the digital realm (Marler, 2018). 1
For older adults, using a smart mobile device to connect to the Internet moderately can improve their quality of life and bring psychological benefits in several ways. Engagement in online discussions provides a platform for older adults to reaffirm their social identity (K. Lee & Lee, 2018); simultaneously, mobile applications emerge as instrumental tools, catering to the dual purpose of building offline social relationships and enriching leisure activities (Kim et al., 2020). These activities contribute to less feeling of loneliness (Khalaila & Vitman-Schorr, 2017; Liu et al., 2024; Yu et al., 2021), lower level of depressive symptoms (Ji et al., 2023; Li et al., 2023; Yang et al., 2024), and higher satisfaction with life (Kim et al., 2021; Lam et al., 2020; Yang et al., 2024). Beyond these immediate benefits, proficient smartphone use is perceived by older adults as a confidence booster, a source of enjoyment, and a catalyst for a broader spectrum of online activities (Cerda Díez et al., 2023; Kurniawan et al., 2006). Moreover, it is also found that using the Internet appropriately can serve as a protective factor against cognitive decline in older adulthood (Yu & Fiebig, 2020).
However, not all older adults can enjoy those benefits. Despite an overall Internet penetration rate of 75.6%, only 54.5% of individuals aged over 60 in China are Internet users (CINIC, 2023), and older Internet users engage in fewer online activities, primarily focusing on basic functions such as daily communication. Less than 40% of older adult users can complete more advanced operations on their own, such as calling a taxi, booking a ticket, or making a medical appointment (CINIC, 2022). Compared with young adults, older adults lag behind in both scope and intensity of Internet usage (Loges & Jung, 2001; Song et al., 2021). The disparity in Internet usage between different age groups is referred to as the “digital divide.” The origin of the term goes back to an unknown American source in the middle of the 1990s and its concept has changed with the development of related research (Scheerder et al., 2017; Van Dijk, 2006). This discourse has shifted from binary Internet access (the first-level digital divide) to skills and use of the Internet (the second-level digital divide), to a focus on the beneficial outcomes of Internet use (the third-level digital divide) (Scheerder et al., 2017). Over the past 30 years, the phenomenon of the digital divide has become increasingly prominent in China, with a huge gap between older and young age groups in terms of the level of IT acceptance, usage frequency, and knowledge acquisition (Huang, 2020).
The Barriers of Low Usage and the Necessity to Measure Proficiency Level
In a survey of non-Internet users, the primary reason for not accessing the Internet, accounting for 58.2% of the total, is the “lack of knowledge and skills,” with only 13.4% citing “lack of interest or need” (CINIC, 2023). This discrepancy suggests that the reluctance among older adults to embrace smartphones may be more attributable to insufficient proficiency than genuine disinterest. This aligns with the constructs of perceived ease of use and perceived usefulness in the Technology Acceptance Model (Davis, 1989). Lack of knowledge and skills can make older adults feel that using a smartphone is too difficult, thus contributing to low perceived ease of use. Lack of interest or need may make older people feel that a smartphone cannot help them with tasks or for recreational purposes, thus diminishing perceived usefulness. Although both perceived ease of use and perceived usefulness act as barriers to smartphone adoption among older adults, the latter is clearly the primary hindrance according to the data.
To address the proficiency barrier, strategic projects such as the “Implementation Plan for Effectively Addressing Difficulties Faced by Older Adults in Using Smart Technologies” and the “Special Action Plan for Internet Application Age-appropriateness and Accessibility Improvement” have been introduced by the General Office of the State Council and the MIIT (Ministry of Industry and Information Technology) of China. These initiatives aim to simplify usage processes or enhance user skills through targeted training, both emphasizing the crucial role of evaluating the proficiency of older adults.
In practice, the assessment of proficiency level can identify the specific operational difficulties faced by older adults. There is significant variation in proficiency among older adults, and some researchers have classified them into three levels: basic, proficient, and advanced users (Rosales & Fernández-Ardèvol, 2019). For example, the basic users may only use the camera or call friends while advanced users may be familiar with all the features other than video games. If we are to optimize interfaces or design tailored training programs, such assessment is inevitable. Besides, using a tool to evaluate proficiency levels at the commencement and conclusion of interventions provides insights into their efficacy.
In theory, conducting assessments can help us further understand the influencing factors of usage proficiency in future research. For example, previous studies have shown that computer usage proficiency is influenced by factors such as age, experience, education level, and emotions (Boot et al., 2015; Zhang et al., 2017), while Internet usage is influenced by age, income, education level, and gender (Elena-Bucea et al., 2021; Loges & Jung, 2001). In China, information literacy among middle-aged and older individuals is associated with education and income levels, with higher education and income leading to stronger information literacy (Chinese Academy of Social Sciences [CASS] & Tencent Center for Society, 2018). Employing statistical analyses like such studies enables a targeted long-term intervention strategy by focusing efforts on specific influencing factors.
Tools to Measure Mobile Device Proficiency of Older Adults
Aligned with the need to assess the operational proficiency of older adults, previous researchers have developed related questionnaires: the Computer Proficiency Questionnaire (CPQ, Boot et al., 2015) and the Mobile Device Proficiency Questionnaire (MDPQ, Roque & Boot, 2018). The CPQ focuses on investigating computer usage skills, covering six dimensions: computer basics, printing, communication, Internet, scheduling software, and multimedia use. Derived and modified from the CPQ, the MDPQ encompasses eight dimensions, including mobile device basics, communication, data and file storage, Internet, calendar, entertainment, privacy, troubleshooting, and software management. Despite the apparent suitability of the MDPQ for our purposes, a meticulous examination of its items reveals its inadequacy for direct application to the Chinese context, even after translation.
First, Chinese older adults are special in that they directly transitioned to the mobile age, rather than transferring from a desktop era as older adults in developed countries. Many of the concepts in a mobile phone such as “homepage,” “wallpaper,” and “installing an app” are inherited from computers. As a result, there is a positive relationship between computer use and the uptake of other mobile devices (Morris et al., 2006), and computer proficiency can serve as a predictive variable for proficiency in smartphones. Hence, the MDPQ and the CPQ have high similarity and relevance in terms of content. However, most Chinese older adults directly became a smartphone user before they had a chance to interact with a computer. Data underscores this phenomenon, with 99.5% of older Chinese Internet users accessing the Internet through smartphones, while computer and other device usage stands at less than 20% (CINIC, 2022). Therefore, we need a new tool that can independently measure proficiency in smartphones.
Second, disparities in preferences for smartphone functions across different countries necessitate a tailored approach. The functions encompassed in the MDPQ fail to capture those commonly used by Chinese older adults. The most frequently used functions among Chinese older Internet users are instant messaging, online video, online government services, online news, and online payment (CINIC, 2022). For example, in 2021, 84.8% of Chinese older Internet users watched online videos (CINIC, 2022), compared to less than 30% in the U.S. in 2022 (Vorhaus Advisors, 2022). When it comes to online news, only about 45% of older users in the U.S. got news on their smartphones (Vorhaus Advisors, 2022), while 77.9% of older users in China often got news this way (CINIC, 2022). Moreover, by the end of December 2022, more than 70% of Chinese residents had helped their parents or other older relatives to use mobile payment (Payment & Clearing Association of China, 2022), but only 28% of older smartphone users in the U.S. purchased products or services online at least once a week (Vorhaus Advisors, 2022). This stark contrast in usage patterns underscores the need for a culturally sensitive measurement tool.
In addition to the aforementioned questionnaires, other questionnaires targeting older adults mainly focus on issues other than technological proficiency. For example, Chen and Lou (2020) gauged older adults’ acceptance of technology, while Anderberg et al. (2019) measured older adults’ attitudes toward technology. These tools also cannot fulfill our specific requirements.
To surmount these limitations, this study endeavors to develop a measurement tool similar to the MDPQ but tailored for evaluating smartphone usage proficiency among Chinese older adults. Beyond fundamental psychometric indicators such as reliability and discrimination, the proposed questionnaire will undergo validation through an examination of its relationship with five predictors: (a) age; (b) daily use duration; (c) years of use; (d) monthly income; and (e) education level. With reference to previous studies, we proposed the following hypotheses to assess the validity of the Smartphone Proficiency Questionnaire for Chinese Older Adults (SPQ-COA).
Methods
Development of the Questionnaire
Collect the Function Set of Smartphones
This study aims to develop a questionnaire for evaluating smartphone usage proficiency among Chinese older adults. Therefore, the questionnaire should encompass fundamental operations routinely performed by older adults on smartphones. Drawing inspiration from existing questionnaires (Boot et al., 2015; Roque & Boot, 2018), recent statistical reports on Internet usage behavior (CASS, 2018; CINIC, 2022), and insights garnered from both personal smartphone usage experiences and interviews with older adults, we listed some mentioned smartphone operations and then conducted task analyses about others. We started with the functions that a smartphone has, and then considered the specific steps that need to be performed for the realization of each function. After all these steps, we compiled an initial function set comprising 71 operations/functions. This function set covers various daily operations on smartphones, including basic operations (turning the device on/off, charging, adjusting font and brightness, etc.), instant messaging (WeChat, SMS, phone calls, etc.), and online financial transactions (using WeChat to transfer money, grabbing and sending electronic red envelops, online payments, etc.).
Merge Related Functions to 30 Items
Adhering to psychometric conventions, each smartphone function should be accessed independently and mutually exclusive. However, insights gleaned from interviews with 20 older adults shows that the initial 71 items would be too challenging for this demographic. Considering the questionnaire’s widespread applicability, it should be concise and short. Consequently, while ensuring the completeness of the questionnaire, we merged related items into more abstract operations. For instance, we consolidated disparate tasks such as “Participate in WeChat group activities, such as grabbing and sending electronic red envelops” and “Use WeChat to transfer money to others” into a singular operation termed “Make financial transactions with family and friends.” In this way, we merged the initial 71 operations into 30 items. Acknowledging that the merging process could compromise clarity and precision, we adopted an innovative format that each abstract operation is accompanied by specific examples to enhance understanding. For instance, following the operation “Adjust device system settings,” examples are given as “Increase the volume, adjust the screen brightness, enlarge the system font.” This approach aims to strike a balance between intelligibility and brevity, ensuring the questionnaire’s practicality for older adult population.
Set the Proficiency Score and Build the Questionnaire
The questionnaire employed a Likert 5-point scale (1 = Cannot complete at all, 2 = Struggle to complete, 3 = Can complete with some effort, 4 = Can complete well, 5 = Complete smoothly), where a higher total score reflects a higher proficiency level. Distinguishing itself from the MDPQ (1 = never tried, 2 = not at all, 3 = not very easily, 4 = somewhat easily, 5 = very easily, Roque & Boot, 2018), our questionnaire emphasizes participants’ ability to “complete” rather than relying on the term “easily” to prevent potential misinterpretations. This nuance ensures that individuals do not consider a task “not easy” just because it has many steps. In this case, when facing operations with multiple steps, participants with high proficiency should rate high (e.g., complete smoothly) rather than low (e.g., not very easily), as they can complete it “smoothly.” The questionnaire includes detailed instructions clarifying the meanings behind these five response options, with participants instructed to select only one option that best aligns with their proficiency level for each operation.
In addition to the 30 merged operations, the questionnaire also collects participants’ basic demographic information, including birth year, gender, daily use duration, years of use, monthly income, and education level. With the exception of the birth year, which is a fill-in-the-blank question, all remaining questions are single-choice questions, requiring participants to indicate the appropriate options relevant to their circumstances.
Pilot Test and Revision
Considering that online testing inherently functions as a selection criterion for usage proficiency among older adults, we opted for a paper-based questionnaire tailored to this demographic. To enhance readability, we increased the font size and line spacing. After forming the initial draft, a pilot test involving 20 older adults (aged 63–88) was conducted. Based on their feedback, we refined the wording and content of the questionnaire, replacing less comprehensible technical terms and providing additional explanations for certain operations.
Participants
Participant Demographics.
The primary target population of this questionnaire is older adult demographic, while the young adult group serves as a control group for subsequent validity assessment. Referring to previous studies (Roque & Boot, 2018), young adults generally possess higher proficiency, making them susceptible to the ceiling effect, meaning that the scores of the young adult group may reach the maximum level detectable by the questionnaire. Therefore, we recruited only 100 participants for the young adult group and administered an online questionnaire. In contrast, the older adult group, our primary focus, received paper-based questionnaires distributed offline, and the participants were supervised by the experimenters to complete the questionnaire on-site. This approach not only avoided technological requirements associated with online questionnaires for older adults but also ensured that older participants would have a comprehensive understanding of the operations and response options, minimizing the potential for invalid responses. Upon completion, all participants received appropriate rewards.
Distribution of the Questionnaire
For the young adult group, we deployed the online questionnaire through the platform powered by Sojump (https://www.wjx.cn/) and disseminated the link through social media channels. For the older adult group, we recruited participants in both Bengbu, Anhui Province and Xi’an, Shaanxi Province. In Bengbu, participants were sourced from congregational areas for older adults, such as the Guzhen Gymnasium and local neighborhoods. In Xi’an, participants were recruited from the vicinity of Shaanxi Normal University. We distributed paper-based questionnaires to older adults, both actively engaging passersby and employing fixed-location advertisement to attract nearby residents. Prior to the anonymous questionnaire, we explicitly declared that all participant responses would be exclusively used for academic research, ensuring strict confidentiality. Therefore, participants’ completion of the questionnaire implied their implicit consent.
Statistical Analysis
Data management and analysis were conducted using SPSS-24, encompassing evaluations of difficulty, discrimination, reliability, and validity. As for validity, we illustrated criteria validity of the questionnaire by formulating three hypotheses and examining the statistical data, including t-values from independent samples t-tests, F-values from one-way ANOVAs, and Pearson correlation coefficients.
Results
Descriptive Statistics
Mean Scores, Standard Deviations, T-test Results and Correlation Coefficients of Questionnaire Items.
aReflects the difference between the older adult group and the young adult group;
bReflects the relationship between the scores of each item and age within the older adult group; *p < .05, **p < .01, ***p < .001.
Item Analysis
Item Analysis Results of the Questionnaire.
Note. Difficulty is calculated as (Total Score - Actual Score)/Total Score; Discrimination data includes Item-Total Correlation (r) and Critical Ratio (CR); all data in the table are significant, with p < .01.
Discrimination includes the critical ratio (CR value) and item-total correlation coefficient (r). By sorting participants’ scores on the 30 items and selecting the top and bottom 27% as the high and low score groups respectively, independent samples t-tests were conducted for each item to determine CR values. The results revealed that all 30 items reached a significance level of 0.01 in both participant groups. Additionally, the item-total correlation coefficients, reflecting the correlation between individual item scores and total scores, were also significant at the 0.01 level for all 30 items in both participant groups. These findings affirm the questionnaire’s robust discrimination. Further details are outlined in Table 3.
Reliability
Cronbach’s α was used to assess the reliability of the 30 items, and the result suggested that the questionnaire is reliable (Cronbach’s α = 0.962).
Validity
Given the absence of localized questionnaires or scales pertaining to smartphone proficiency in China, criteria validity of this questionnaire could not be validated through existing instruments. Nonetheless, in line with previous studies (Roque & Boot, 2018), we proposed three hypotheses to demonstrate the criteria validity of the questionnaire:
If the questionnaire is valid, the scores of the young adult group should be significantly higher than those of the older adult group.
Drawing on existing research and the digital divide theory, younger individuals generally exhibit higher proficiency in technology usage compared to older individuals. Therefore, we hypothesized that if the questionnaire would accurately measure participants’ smartphone usage proficiency, the scores of the older group should be lower than those of the young group for each item. Independent samples t-tests were conducted for each item to compare the scores of the older adult and young adult groups, revealing significantly lower scores for the older adult group across all 30 items (|t| ≥ 7.69, p < .001). The results can be seen in Table 2 Column 6, supporting H1.
If the questionnaire is valid, the scores of the older adult group should be correlated with age, with higher age being associated with lower scores.
Individuals who were older in age were expected to have lower operational skills compared to those who were younger among the older adult group. We calculated the Pearson correlation coefficients (r) between the age of the older participants (a continuous variable) and the scores of the 30 items. The results as shown in Table 2 Column 7, indicated a significant negative correlation between age and scores for all items among the older adult group (rmax = −0.11, p < .05). This finding suggested that as age increased in the older population, their operational skill levels tended to be lower, supporting H2.
If the questionnaire is valid, there should be differences in scores among the older adult group based on daily use duration, years of use, monthly income, and education level.
F-test Results for Questionnaire Scores Across Daily Use Duration, Years of Use, Monthly Income, and Education Level.
Note. The data that are not significant are marked with a gray background color, and the remaining data are significant at different levels, *p < .05, **p < .01, ***p < .001.

The Score of Each Item Among Different Older Adults.
With all three hypotheses validated and aligned with existing research and recent data, we assert that the questionnaire demonstrates strong criteria validity.
Discussion
Evaluation of the Questionnaire
Measuring the level of operational proficiency in using smartphones is a crucial step in improving digital literacy among older adults and helping them bridge the digital divide. This study is positioned to address this issue by developing a reliable and valid measurement questionnaire tailored for Chinese residents. The questionnaire consists of 30 self-assessment items on operational skills. Through rigorous validation, this questionnaire has demonstrated its ability to measure self-assessed operational proficiency.
A distinctive feature of our questionnaire, compared to counterparts like MDPQ, lies in its cultural alignment with Chinese older adults. In terms of content, our questionnaire includes daily operations commonly used by Chinese residents, such as “Scan QR codes with devices,” “Make purchases online,” “Conduct payments of fees online,” and “Travel and navigate.” Omitted are trivial and infrequently used tasks from previous questionnaires, such as “Send an email to multiple recipients simultaneously” and “Access my files from anywhere through cloud storage.” This is because, compared with email, Chinese older adults more commonly use WeChat as their communication medium (CASS, 2018). In terms of expression, language localization and life-oriented examples enhance comprehension, making the questionnaire a culturally sensitive tool. For instance, the explanation for “Interact on social apps” includes examples as “Give a thumbs-up on moments, share an article to other WeChat groups.”
Assessing the operational proficiency of smartphones among Chinese residents and investigating influencing factors contributes to the advancement of research on tailored skill training and product design for older adults, further providing personalized solutions to bridge the digital divide. Additionally, this questionnaire can function as a valuable tool to evaluate the effectiveness of skill training programs for older adults and provide insights for developing supportive policies that align with China’s national conditions to enhance digital literacy among older adults.
Findings on Smartphone Usage Patterns and Implications
In addition to developing a new questionnaire suitable for Chinese older adults, we have also verified the basic smartphone usage proficiency level among older adults in China and identified factors that influence their skill levels. The 5-point self-assessment revealed an average score of 3.34 for older adults and 4.76 for young adults, highlighting a significant proficiency gap. Lower scores on specific items reflected challenges faced by older adults. For example, the lower score on the item “Book an appointment online” aligns with previous findings that “only 12.1% of older adults can use mobile phones for online registration” (CASS, 2018), indicating that many older adults are unable to make appointments online. Correspondingly, the challenge of “being unable to book tickets or make registrations” has also been one of the common inconveniences among older individuals (CINIC, 2023). From an operational perspective, to complete the “Book an appointment online” task, users typically need to download or subscribe to a specific platform, which may involve multiple operations such as verifying personal information, entering verification codes, searching for services, and so on. These processes require flexibility and overall proficiency, thus posing higher technological demands on the older population. This also suggests that some commonly used operations with higher difficulty level should be a focal point for future skill training and product design for older adults. This analysis guides future interventions by pinpointing high-difficulty operations that demand enhanced technological proficiency.
Regarding influencing factors, we found differences in questionnaire scores based on age, daily use duration, years of use, monthly income, and education level. The relationship between proficiency and age is not only evident in the intergroup differences between the older and young adult groups but also within the older adult group, with a general trend that proficiency decreases as age increases. In the older adult population, longer daily use duration, more years of use, higher monthly income, and higher education level are associated with higher proficiency. These findings align with our initial hypothesis that there are variations in smartphone usage proficiency among older adults and that they are influenced by certain factors. These factors can serve as starting points for bridging the digital divide.
Limitations
We must acknowledge that we designed this questionnaire for pragmatic reasons, and therefore the process of development was not totally theory-driven, leading to a dimensionless structure. However, it is beneficial to extract dimensions in a questionnaire, as it enables further analysis of specific skill areas older adults need to focus on. A potential way is to conduct a cognitive task analysis (Knisely et al., 2021) of older adults’ interaction with smartphones and propose dimensions that can reflect more basic cognitive operations such as “information retrieval” and “navigation through apps” rather than the specific functions. In future research, we anticipate updating the questionnaire to enhance its stability, covering a broader range of fundamental and trainable abilities.
In terms of the factors that influence older adults’ proficiency in smartphone use, beyond the four considered here, future research should also consider whether the types of work older adults held before retirement will affect their attitudes and proficiency levels in using smartphones after retirement, and thus to better provide targeted support in smartphone usage for older adults.
Conclusion
This study developed a 30-item self-assessment questionnaire for measuring smartphone usage proficiency and the 30 items cover basic operations performed by Chinese residents in their daily use. The questionnaire exhibited satisfactory reliability and validity, moderate difficulty, and qualified discrimination, aligning with psychological measurement standards, so it stands as an effective tool for assessing the smartphone proficiency in Chinese residents. Our findings indicated significantly lower smartphone proficiency in individuals aged 60 and above compared to their younger counterparts. Additionally, we discovered that within the older adult population, higher scores were associated with lower age, longer daily use duration, more years of use, higher monthly income, and higher education level.
Supplemental Material
Supplemental Material - The Development of the Smartphone Proficiency Questionnaire for Chinese Older Adults (SPQ-COA)
Supplemental Material for The Development of the Smartphone Proficiency Questionnaire for Chinese Older Adults (SPQ-COA) by Ningyi Du, Qingxian Zhao, Chunyu Zhang, Guojie Ma, and Xiangling Zhuang in Journal of Applied Gerontology.
Footnotes
Acknowledgments
Our gratitude to all the participants who gave their precious time to be interviewed for this study. We also appreciate Siyuan Qiao, Changlin Luo, and Tuo Zhang’s help in collecting the data.
Authors’ Note
We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us. We confirm that we have given due consideration to the protection of intellectual property associated with this work and that there are no impediments to publication, including the timing of publication, with respect to intellectual property. In so doing we confirm that we have followed the regulations of our institutions concerning intellectual property. We understand that the Corresponding Author is the sole contact for the Editorial process (including Editorial Manager and direct communications with the office). He/she is responsible for communicating with the other authors about progress, submissions of revisions and final approval of proofs. We confirm that we have provided a current, correct email address which is accessible by the Corresponding Author and which has been configured to accept email from (
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the National Natural Science Foundation of China (32371128, 31970998), the Fundamental Research Funds for the Central Universities [GK202301002], and the key project of Chongqing Technology Innovation and Application Development [cstc2021jscx-dxwtBX0020].
Ethical Statement
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References
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