| 1. |
- Beal, Jacob, et al.
(författare)
-
Robust estimation of bacterial cell count from optical density
- 2020
-
Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
|
|
| 2. |
- Zhang, Xueli, et al.
(författare)
-
CBD2 : A functional biomarker database for colorectal cancer
- 2024
-
Ingår i: iMeta. - : John Wiley & Sons. - 2770-5986 .- 2770-596X. ; 3:1
-
Tidskriftsartikel (refereegranskat)abstract
- The rapidly evolving landscape of biomarkers for colorectal cancer (CRC) necessitates an integrative, updated repository. In response, we constructed the Colorectal Cancer Biomarker Database (CBD), which collected and displayed the curated biomedicine information for 870 CRC biomarkers in the previous study. Building on CBD, we have now developed CBD2, which includes information on 1569 newly reported biomarkers derived from different biological sources (DNA, RNA, protein, and others) and clinical applications (diagnosis, treatment, and prognosis). CBD2 also incorporates information on nonbiomarkers that have been identified as unsuitable for use as biomarkers in CRC. A key new feature of CBD2 is its network analysis function, by which users can investigate the visible and topological network between biomarkers and identify their relevant pathways. CBD2 also allows users to query a series of chemicals, drug combinations, or multiple targets, to enable multidrug, multitarget, multipathway analyses, toward facilitating the design of polypharmacological treatments for CRC. CBD2 is freely available at http://www.eyeseeworld.com/cbd.
|
|
| 3. |
- Deng, Qiuzhuo, et al.
(författare)
-
Quantum Noise Secured Terahertz Communications
- 2023
-
Ingår i: 2023 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION, OFC. - : Optica Publishing Group.
-
Konferensbidrag (refereegranskat)abstract
- The quantum noise based terahertz signal encryption scheme is proposed, a 16 Gbits(-1) secure terahertz communication system at 300 GHz with the optical communication realms is demonstrated, taking a significant step toward high-security wireless communications.
|
|
| 4. |
- Deng, Qiuzhuo, et al.
(författare)
-
Quantum Noise Secured Terahertz Communications
- 2023
-
Ingår i: 2023 Optical Fiber Communications Conference and Exhibition (OFC).
-
Konferensbidrag (refereegranskat)abstract
- The quantum noise based terahertz signal encryption scheme is proposed, a 16 Gbits-1 secure terahertz communication system at 300 GHz with the optical communication realms is demonstrated, taking a significant step toward high-security wireless communications.
|
|
| 5. |
- Georgiou, Konstantinos, et al.
(författare)
-
Genetic basis of PD-L1 overexpression in diffuse large B-cell lymphomas
- 2016
-
Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 127:24, s. 3026-3034
-
Tidskriftsartikel (refereegranskat)abstract
- Diffuse large B-cell lymphoma (DLBCL) is one of the most common and aggressive types of B-cell lymphoma. Deregulation of proto-oncogene expression after a translocation, most notably to the immunoglobulin heavy-chain locus (IGH), is one of the hallmarks of DLBCL. Using whole-genome sequencing analysis, we have identified the PD-L1/PD-L2 locus as a recurrent translocation partner for IGH in DLBCL. PIM1 and TP63 were also identified as novel translocation partners for PD-L1/PD-L2. Fluorescence in situ hybridization was furthermore used to rapidly screen an expanded DLBCL cohort. Collectively, a subset of samples was found to be affected by gains (12%), amplifications (3%), and translocations (4%) of the PD-L1/PD-L2 locus. RNA sequencing data coupled with immunohistochemistry revealed that these cytogenetic alterations correlated with increased expression of PD-L1 but not of PD-L2. Moreover, cytogenetic alterations affecting the PD-L1/PD-L2 locus were more frequently observed in the non-germinal center B cell-like (non-GCB) subtype of DLBCL. These findings demonstrate the genetic basis of PD-L1 overexpression in DLBCL and suggest that treatments targeting the PD-1-PD-L1/PD-L2 axis might benefit DLBCL patients, especially those belonging to the more aggressive non-GCB subtype.
|
|
| 6. |
- Li, Qianyi, et al.
(författare)
-
“Hiding in the Crowd?” In Pursuit of Perceived Anonymity through a Uniform Visual Presentation on Algorithm-driven Social Media Platforms
- 2024
-
Ingår i: Pacific Asia Conference on Information Systems 2024.
-
Konferensbidrag (refereegranskat)abstract
- Collective anonymity is defined as a large group of social media users collectively adopting a uniform identification presentation (e.g., an identical online pseudonym and avatar). This emerging trend is increasingly prevalent on algorithm-driven social media, proactively leveraged by users to increase perceived anonymity. To conceptualize it and understand its drivers and outcomes, this study investigated one exemplary form of collective anonymity on Xiaohongshu. Using an inductive approach, interview data with fourteen participants was collected and analysed through a thematic approach. Our findings (a) explained the underlying mechanisms of collective anonymity; (b) unpacked users’ internal motivations and extrinsic factors that drive it; (c) uncovered its downstream consequences pertinent to human-human interaction and human-algorithm engagement. Our study also provides important implications on algorithmic regulation and governance, the ethical use of algorithmic recommendations, and the mitigation of disinhibited and deviant behaviour resulting from collective anonymity.
|
|
| 7. |
- Wang, Tong, et al.
(författare)
-
Deep defect passivation and shallow vacancy repair via an ionic silicone polymer toward highly stable inverted perovskite solar cells
- 2022
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 15:10, s. 4414-4424
-
Tidskriftsartikel (refereegranskat)abstract
- Additive engineering is an effective strategy for defect passivation and performance improvement of perovskite solar cells (PSCs). However, few additives have achieved outstanding stability with high efficiency by simultaneously passivating deep and shallow defects. Herein, we design a novel ionic silicone polymer (PECL) with multi-active sites as an additive to modify inverted PSCs. The C-O groups in the PECL polymer can chelate with undercoordinated Pb2+ and Pb clusters to passivate deep defects; and the ionic groups in the PECL polymer can generate electrostatic interaction with both positively and negatively charged vacancies, which help to repair shallow defects. Moreover, we quantitatively reveal the effect of deep and shallow defects on the efficiency and stability of PSCs separately, by establishing the correlation between additives with different functional groups and the performance of devices. Consequently, the power conversion efficiency of the PECL-modified inverted PSC increases from 20.02% to 23.11%. More importantly, the encapsulated PSCs maintain 95% of their initial steady-state power output after 1500 hours under AM 1.5 illumination at the maximum power point at 45 degrees C. Therefore, we provide a universal guideline of polymer structure design for defect healing in stabilizing PSCs with high efficiency.
|
|
| 8. |
- Bumann, Adrian, et al.
(författare)
-
Predicting the spread of invasive marine species with open data and machine learning: Process and Challenges
- 2021
-
Ingår i: International Conference on Marine Data and Information Systems (IMDIS) 2021.
-
Konferensbidrag (refereegranskat)abstract
- One of the world’s most complex marine challenges is the spread of invasive species. Invasive species cause severe harm to marine ecosystems and the people who depend on them, with economic impact alone amounting to several billion dollars annually. Recent advances in data science and artificial intelligence (AI) along with the increasing availability of free marine and other data online are improving the possibility to tackle these challenges. This paper presents the efforts by Ocean Data Factory Sweden (ODF Sweden), a data-driven innovation consortium in Gothenburg, to apply machine learning (ML) to one use case – the prediction of the spread of the Killer Shrimp, or Dikerogammarus Villosus, into the Baltic Sea (Figure 1). We discuss our process to address this use case as well as some reflections on the process and its challenges, in particular when taking into consideration the FAIR (findable, accessible, interoperable and reusable) principles in data science.
|
|
| 9. |
- Bumann, Adrian, et al.
(författare)
-
The Killer Shrimp Invasion Challenge on Kaggle: An online competition tackling the spread of invasive marine species through machine learning
- 2021
-
Ingår i: International Conference on Marine Data and Information Systems (IMDIS) 2021.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The world faces numerous complex marine challenges, such as overfishing, the spread of invasive species, and rising sea levels. These challenges are interconnected with the 17 UN Sustainable Development Goals, and in particular Goal #14 - Life below water. A paradox for any action related to the ocean is that while there is an enormous lack of ocean data, there is also an abundance of online marine and geo data that could be used to develop solutions through the application of artificial intelligence (AI). Open innovation and crowdsourcing could be a solution to such complex problems; however, applying data science to solve marine challenges through these open strategies is limited. Responding to the above, Ocean Data Factory Sweden (ODF Sweden), a data-driven innovation consortium in Gothenburg, developed an online competition, The Killer Shrimp Invasion Challenge (Figure 1). The competition was launched on the data science competition platform, Kaggle, in the spring of 2020 to address the spread of the invasive Killer Shrimp through applying machine learning (ML) to online data. This paper will describe the Killer Shrimp use case, the launch of the Kaggle competition, competition results and reflections on this form of tackling marine challenges.
|
|
| 10. |
- Cao, Qi, et al.
(författare)
-
N-Type Conductive Small Molecule Assisted 23.5% Efficient Inverted Perovskite Solar Cells
- 2022
-
Ingår i: Advanced Energy Materials. - : John Wiley & Sons. - 1614-6832 .- 1614-6840. ; 12:34
-
Tidskriftsartikel (refereegranskat)abstract
- Because of the compatibility with tandem devices and the ability to be manufactured at low temperatures, inverted perovskite solar cells have generated far-ranging interest for potential commercial applications. However, their efficiency remains inadequate owing to various traps in the perovskite film and the restricted hole blocking ability of the electron transport layer. Thus, in this work, a wide-bandgap n-type semiconductor, 4,6-bis(3,5-di(pyridin-4-yl)phenyl)-2-phenylpyrimidine (B4PyPPM), to modify a perovskite film via an anti-solvent method is introduced. The nitrogen sites of pyrimidine and pyridine rings in B4PyPPM exhibit strong interactions with the undercoordinated lead ions in the perovskite material. These interactions can reduce the trap state densities and inhibit nonradiative recombination of the perovskite bulk. Moreover, B4PyPPM can partially aggregate on the perovskite surface, leading to an improvement in the hole-blocking ability at its interface. This modification can also increase the built-in potential and upshift the Fermi level of the modified perovskite film, promoting electron extraction to the electron transport layer. The champion device achieves a high efficiency of 23.51%. Meantime, the sealed device retains approximate to 80% of its initial performance under a maximum power point tracking for nearly 2400 h, demonstrating an excellent operational stability.
|
|
| 11. |
- Costello, David M., et al.
(författare)
-
Global patterns and controls of nutrient immobilization on decomposing cellulose in riverine ecosystems
- 2022
-
Ingår i: Global Biogeochemical Cycles. - : John Wiley & Sons. - 0886-6236 .- 1944-9224. ; 36:3
-
Tidskriftsartikel (refereegranskat)abstract
- Microbes play a critical role in plant litter decomposition and influence the fate of carbon in rivers and riparian zones. When decomposing low-nutrient plant litter, microbes acquire nitrogen (N) and phosphorus (P) from the environment (i.e., nutrient immobilization), and this process is potentially sensitive to nutrient loading and changing climate. Nonetheless, environmental controls on immobilization are poorly understood because rates are also influenced by plant litter chemistry, which is coupled to the same environmental factors. Here we used a standardized, low-nutrient organic matter substrate (cotton strips) to quantify nutrient immobilization at 100 paired stream and riparian sites representing 11 biomes worldwide. Immobilization rates varied by three orders of magnitude, were greater in rivers than riparian zones, and were strongly correlated to decomposition rates. In rivers, P immobilization rates were controlled by surface water phosphate concentrations, but N immobilization rates were not related to inorganic N. The N:P of immobilized nutrients was tightly constrained to a molar ratio of 10:1 despite wide variation in surface water N:P. Immobilization rates were temperature-dependent in riparian zones but not related to temperature in rivers. However, in rivers nutrient supply ultimately controlled whether microbes could achieve the maximum expected decomposition rate at a given temperature. Collectively, we demonstrated that exogenous nutrient supply and immobilization are critical control points for decomposition of organic matter.
|
|
| 12. |
- Dong, John Qi, et al.
(författare)
-
The faster the better? Innovation speed and user interest in open source software
- 2019
-
Ingår i: Information & Management. - : Elsevier BV. - 0378-7206. ; 56:5, s. 669-680
-
Tidskriftsartikel (refereegranskat)abstract
- It is often believed that for open source software (OSS) projects the faster the release, the better for attracting user interest in the software. Whether this is true, however, is still open to question. There is considerable information asymmetry between OSS projects and potential users as project quality is unobservable to users. We suggest that innovation speed of OSS project can signal the unobservable project quality and attract users’ interest in downloading and using the software. We contextualize innovation speed of OSS projects as initial release speed and update speed and examine their impacts on user interest. Drawing on the signaling theory, we propose a signaling effect through which a higher initial release speed or update speed increases user interest, while the effect diminishes as initial release or update speed increases. Using a large-scale panel data set from 7442 OSS projects on SourceForge between 2007 and 2010, our results corroborate the inverted U-shaped relationships between initial release speed and user downloads and between update speed and user downloads.
|
|
| 13. |
- Gehrmann, Sebastian, et al.
(författare)
-
GEMv2: Multilingual NLG Benchmarking in a Single Line of Code
- 2022
-
Ingår i: Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing: System Demonstrations. - : Association for Computational Linguistics (ACL). ; , s. 266-281
-
Konferensbidrag (refereegranskat)abstract
- Evaluations in machine learning rarely use the latest metrics, datasets, or human evaluation in favor of remaining compatible with prior work. The compatibility, often facilitated through leaderboards, thus leads to outdated but standardized evaluation practices. We pose that the standardization is taking place in the wrong spot. Evaluation infrastructure should enable researchers to use the latest methods and what should be standardized instead is how to incorporate these new evaluation advances.We introduce GEMv2, the new version of the Generation, Evaluation, and Metrics Benchmark which uses a modular infrastructure for dataset, model, and metric developers to benefit from each other’s work. GEMv2 supports 40 documented datasets in 51 languages, ongoing online evaluation for all datasets, and our interactive tools make it easier to add new datasets to the living benchmark.
|
|
| 14. |
|
|
| 15. |
- Jia, Xue, et al.
(författare)
-
CsPb(IxBr1-x)(3) solar cells
- 2019
-
Ingår i: Science Bulletin. - : ELSEVIER. - 2095-9273. ; 64:20, s. 1532-1539
-
Tidskriftsartikel (refereegranskat)abstract
- Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell (PSC) becomes a promising candidate for next-generation high-efficiency solar cells. The power conversion efficiency (PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)(3) and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)(3) solar cells and outline possible directions to further improve the device performance. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.
|
|
| 16. |
- Kuem, Jungwon, et al.
(författare)
-
How Does Performance-Based Monetary Incentive Influence Cyberloafing’s Effects on Task Performance?
- 2024
-
Ingår i: Information Systems Frontiers. - 1387-3326 .- 1572-9419.
-
Tidskriftsartikel (refereegranskat)abstract
- With the widespread use of computers and the internet in the workplace, computer use for personal reasons during work time, or cyberloafing, has become quite common. Without a clear understanding of the consequences of cyberloafing, practitioners cannot properly design an IT policy aimed at managing employees' cyberloafing. This study aims to develop and test a model of the relationship between cyberloafing and task performance. Specifically, we attempt to demonstrate how performance-based monetary incentives and time change the role of cyberloafing in task performance. Drawing on the theory of goal setting and the capacity theory of attention, we developed research hypotheses on how cyberloafing interacts with incentives and time to influence task performance. To test the hypotheses, we conducted five 2 × 2 experiments repeatedly on 189 subjects. The results of hierarchical linear modeling showed that although cyberloafing generally worsened task performance, this relationship varied with performance-based monetary incentives. Incentives significantly diminished the negative effect of cyberloafing on task performance. However, as our theory predicted, the moderating effect of incentives decreased over time. More specifically, we found that the two-way interaction between cyberloafing and incentives was in effect during earlier phases but gradually disappeared over time. This study contributes to IS research and practice by providing valuable insights into the role of cyberloafing in task performance and how this relationship changes over time with the option of performance-based monetary incentives.
|
|
| 17. |
- Laatikainen, Gabriella, et al.
(författare)
-
ICO Crowdfunding: Incentives, Pricing Strategy, Token Strategy and Crowd Involvement
- 2020
-
Ingår i: XP 2020: Agile Processes in Software Engineering and Extreme, International Conference on Agile Software Development.
-
Konferensbidrag (refereegranskat)abstract
- Blockchain technologies provide means to develop services that are secure, transparent and efficient by nature. Unsurprisingly, the emerging business opportunities has gained a lot of interest that is realized in form of successful Initial Coin Offerings (ICOs) that are able to raise billions of USD through crowdfunding campaign. In this exploratory research we study 91 ICOs through content analysis in order to investigate the special characteristics of ICO crowdfunding as business models towards the possible investors. We found that ICOs can be described through (1) the model for providing incentives for investment, (2) the pricing strategy, (3) the token strategy and (4) the activities for crowd involvement in value co-creation.
|
|
| 18. |
- Laatikainen, Gabriella, et al.
(författare)
-
What Key Aspects Do ICOs Reveal About Their Businesses?
- 2020
-
Ingår i: XP 2020: Agile Processes in Software Engineering and Extreme, International Conference on Agile Software Development. - Cham : Springer International Publishing.
-
Konferensbidrag (refereegranskat)abstract
- Blockchain technologies disrupt industries by enabling decentralized and transactional data sharing across a network of untrusted participants, among others. Initial Coin Offerings (ICOs) are a novel form of crowdfunding through which hundreds of blockchain-enabled businesses manage to raise billions of dollars in total only in United States. However, there is a lack of understanding of the ICO phenomenon especially related to the business aspects. In this paper, we describe the results of an exploratory study of 91 ICOs and identify the key business model elements that ICOs reveal in their websites and whitepapers. Furthermore, we also note the immaturity and lack of transparency of the business aspects of businesses behind the ICO campaigns.
|
|
| 19. |
- Li, Yuling, et al.
(författare)
-
Bilateral Teleoperation of Multiple Robots under Scheduling Communication
- 2020
-
Ingår i: IEEE Transactions on Control Systems Technology. - 1063-6536. ; 28:5, s. 1770-1784
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, bilateral teleoperation of multiple slaves coupled to a single master under scheduling communication is investigated. The sampled-data transmission between the master and the multiple slaves is fulfilled over a delayed communication network, and at each sampling instant, only one slave is allowed to transmit its current information to the master side according to some scheduling protocols. To achieve the master-slave synchronization, round-robin (RR) scheduling protocol and try-once-discard (TOD) scheduling protocol are employed, respectively. By designing a scheduling-communication-based controller, some sufficient stability criteria related to the controller gain matrices, sampling intervals, and communication delays are obtained for the closed-loop teleoperation system under the RR and TOD scheduling protocols, respectively. Finally, simulation studies are given to validate the effectiveness of the proposed results.
|
|
| 20. |
- Li, Yuling, et al.
(författare)
-
Composite Adaptive Control for Bilateral Teleoperation Systems without Persistency of Excitation
- 2020
-
Ingår i: Journal of the Franklin Institute. - : Elsevier BV. - 0016-0032. ; 357:2, s. 773-795
-
Tidskriftsartikel (refereegranskat)abstract
- Composite adaptive control schemes, which use both the system tracking error and the prediction error to drive the updating law, have become widespread in achieving an improvement of system performance. However, a strong persistent-excitation (PE) condition is required to guarantee the convergence of the parameter estimation errors. This paper proposes a novel composite adaptive control for nonlinear teleoperation systems with dynamic uncertainties and time-varying communication delays, by which the parameter convergence is achieved without the PE condition. The novelty lies in the construction of the prediction errors by designing lower-bounded gain matrices of the prediction errors. The stability criteria of the closed-loop teleoperation system are given in terms of linear matrix inequalities. Simulation studies are given to show the effectiveness of the proposed method.
|
|
| 21. |
- Li, Yuling, et al.
(författare)
-
Neural-Network-Based Adaptive Control for Bilateral Teleoperation with Multiple Slaves under Round-Robin Scheduling Protocol
- 2021
-
Ingår i: International Journal of Control. - : Informa UK Limited. - 0020-7179 .- 1366-5820. ; 94:6, s. 1461-1474
-
Tidskriftsartikel (refereegranskat)abstract
- A neural-network-based adaptive control scheme is developed for bilateral teleoperation systems with single-master-multiple-slaves in the presence of dynamic uncertainties and communication constraint. Discrete-time data transmitting communication network with bandwidth limitation and time-varying communication delays is considered and the Round-Robin scheduling protocol is used to orchestrate the data transmission from multiple slaves to the master. Stability criteria of the closed-loop system are established by constructing appropriate Lyapunov-Krasovskii functionals. Simulation studies are performed to illustrate the effectiveness of the proposed control algorithm.
|
|
| 22. |
- Li, Yingkui, et al.
(författare)
-
Timing and extent of Quaternary glaciations in the Tianger Range, eastern Tian Shan, China, investigated using Be-10 surface exposure dating
- 2014
-
Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 98, s. 7-23
-
Tidskriftsartikel (refereegranskat)abstract
- Reconstructing glacial chronologies with consistent methods is critical for efforts to examine the timing and pattern of past climate change. Cosmogenic Be-10 surface exposure dating has been widely used to constrain the timing of glacial events on the Tibetan Plateau and in Central Asia. However, few such studies have been conducted in the Chinese Tian Shan and available Be-10 ages from this region have only provided evidence for glacial events during the global Last Glacial Maximum (gLGM) and Lateglacial. Here, we present 45 Be-10 surface exposure ages from glacial landforms in the Ala and Daxi valleys, two formerly glaciated valleys draining the Tianger Range, eastern Tian Shan. Combined with previously published Be-10 surface exposure ages from the Daxi Valley in the source area of the Urumqi River, the new ages record five major glacial events during Marine Oxygen Isotope Stages (MIS) 6 or older, 4, 3, 2, and 1 (during the Little Ice Age, LIA). Landforms from glacial events since MIS 2 are found on the northern slope of the Tianger Range (Daxi Valley), whereas evidence for the older glacial events is only preserved on its southern slope (Ala Valley). This disparity may be caused by different preservation- and micro-climatic conditions on the northern and southern slopes of this mountain range, due to differences in gradient and aspect. The LIA glacial advances are apparently the only Holocene glacial event recorded in this area. Earlier Holocene glacial events were probably so restricted in extent that they were destroyed by subsequent LIA advances.
|
|
| 23. |
- Persson, Per, 1968, et al.
(författare)
-
Technical Debt in the Municipality Sector - The Missing Link with Citizens and Silofication
- 2023
-
Ingår i: The 14th Scandinavian Conference of Information Systems. - : Association for Information Systems.
-
Konferensbidrag (refereegranskat)abstract
- Public sector organizations suffer from high levels of technical debt (TD). TD leaves digital infrastructures in a derelict state, making digital transformations costly and risky. Though there is growing research about TD, most studies focus on private businesses, and there is a lack of research about TD in the public sector. In this study, we conduct a case study examining the TD in a Swedish municipality, analyzing archival data such as project reports, municipality blog posts on digital transformation, and goals to improve citizen experience. We focus on four information systems that support permit application processes. Analysis results reveal the common TD types, consequences, and possible causes. Departments work in silos, the case manager perspective is prevalent in requirements, and the citizens only have a limited passive role as system users leading to various types of TD and high costs when integrating legacy systems into a coherent IT architecture. By diving deep into the data from a specific forerunner municipality, we identify TD and increase our understanding of how debt influences digital transformation. Results give a stable ground for further research and practice on mitigating the debt.
|
|
| 24. |
- Persson, Per, 1968, et al.
(författare)
-
Toward Citizen-Centered Digital Government : Design Principles Guided Legacy System Renewal in A Swedish Municipality
- 2024
-
Ingår i: Proceedings of the 57th Hawaii International Conference on System Sciences. - : ScholarSpace. - 1530-1605 .- 2572-6862. - 9780998133171 ; , s. 1963-1972
-
Konferensbidrag (refereegranskat)abstract
- Transformation towards a digital government imposes significant demands on the capabilities of legacy infrastructure. We closely followed a Swedish municipality that designed and implemented a solution to improve the building permit application process with an aim to improve citizen service. We developed six design principles (DPs): availability, timeliness, actionability, transparency, personalization, and generalizability. These DPs guide the solution design and provide a seamless application experience for citizens and business owners. We also discuss the reasoning behind the design choices and the implications of the solution. The artifact encompasses understanding citizens’ needs, identifying constraints of the legacy systems, formulating design principles, and developing architectural designs. However, addressing the social aspects of legacy systems, such as organizational culture change, necessitates additional steps, and is worth investigation in future studies.
|
|
| 25. |
- Shangguan, Zhichun, et al.
(författare)
-
A rechargeable molecular solar thermal system below 0 °C
- 2022
-
Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6539 .- 2041-6520. ; 13:23, s. 6950-6958
-
Tidskriftsartikel (refereegranskat)abstract
- An optimal temperature is crucial for a broad range of applications, from chemical transformations, electronics, and human comfort, to energy production and our whole planet. Photochemical molecular thermal energy storage systems coupled with phase change behavior (MOST-PCMs) offer unique opportunities to capture energy and regulate temperature. Here, we demonstrate how a series of visible-light-responsive azopyrazoles couple MOST and PCMs to provide energy capture and release below 0 degrees C. The system is charged by blue light at -1 degrees C, and discharges energy in the form of heat under green light irradiation. High energy density (0.25 MJ kg(-1)) is realized through co-harvesting visible-light energy and thermal energy from the environment through phase transitions. Coatings on glass with photo-controlled transparency are prepared as a demonstration of thermal regulation. The temperature difference between the coatings and the ice cold surroundings is up to 22.7 degrees C during the discharging process. This study illustrates molecular design principles that pave the way for MOST-PCMs that can store natural sunlight energy and ambient heat over a wide temperature range.
|
|
| 26. |
- Säynätmäki, Olli, et al.
(författare)
-
Understanding the elderly and their next of kin’s usage of mobile personal safety service
- 2020
-
Ingår i: Journal of Systems and Information Technology. - 1328-7265. ; 22:2, s. 137-159
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose This study aims to understand elderly people and their family members’ perceptions and usage of a mobile personal safety service. Design/methodology/approach The study adopts both interviews and analysis of actual usage data to cross-validate the findings. Four family groups and 11 subjects participated in the study. Findings Elderly people are willing to learn to use the mobile safety service, and some elderly people explore more features than their younger family members. Family support facilitates their learning. Elderly people feel psychologically secure when using the mobile safety service. Privacy concerns are mitigated because they consider location sharing is necessary for the service. Research limitations/implications The current sample is small, as it involves collection of both interview data and actual usage data. Considering the emergency of the mobile personal safety service, the study is exploratory. Practical implications The findings suggest that elderly people are willing to learn and use technology such as the mobile safety service, which is relevant to their daily lives. Designers may think about how to highlight the relevancy aspect of technologies in elderly peoples’ lives. Originality/value This study is one of the earliest studies about elderly people’s usage of mobile safety service. This study reveals that elderly people are willing to learn to use the mobile safety service and explore its features. Technical support from family members and relevancy of the service in their daily lives may encourage them to use the technology.
|
|
| 27. |
- Tiegs, Scott D., et al.
(författare)
-
Global patterns and drivers of ecosystem functioning in rivers and riparian zones
- 2019
-
Ingår i: Science Advances. - Washington : American Association of Advancement in Science. - 2375-2548. ; 5:1
-
Tidskriftsartikel (refereegranskat)abstract
- River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth's biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented "next-generation biomonitoring" by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale.
|
|
| 28. |
- Tona, Olgerta, et al.
(författare)
-
Role of Data in the Building of Legitimacy for Green Bonds — Capturing, Contextualizing, and Communicating
- 2023
-
Ingår i: Proceedings of the Annual Hawaii International Conference on System Sciences. - 1530-1605. - 9780998133164
-
Konferensbidrag (refereegranskat)abstract
- Green bond markets promise to fight climate change by encouraging green investments. Yet, the real-world complexity of quantifying the green impact of sustainable initiatives might be exploited for greenwashing, thus threatening the entire market's credibility. Advances in business analytics research and practice hold the potential to untangle this complexity. This study aims to explore how one can engage with data to build the legitimacy of green bonds. In particular, we detail data-related needs, requirements, and challenges that are critical to take into account for designing relevant and effective information system artifacts that will support green bond markets. Through focus groups, interviews, and secondary data analysis, we identify capturing, contextualizing, and communicating green impact as core activities for bond issuers toward ensuring legitimacy for their green bonds. Based on these findings, we outline future research avenues and propose an initial set of research questions for the business analytics and, more broadly, information systems community.
|
|
| 29. |
- Tuunanen, Tuure, et al.
(författare)
-
Micro-Level Mechanisms to Support Value Co-Creation for Design of Digital Services
- 2023
-
Ingår i: Journal of Service Research. - 1094-6705 .- 1552-7379.
-
Tidskriftsartikel (refereegranskat)abstract
- This study identifies micro-level value co-creation mechanisms that support the design of digital services. As services are now becoming digital—or at least digitally enabled—how to design digital services that enable value co-creation between a service provider and customers has become an increasingly important question. Our qualitative research study provides one answer to this question. Based on 113 in-depth laddering interviews analyzed using interpretive structural modeling, our study shows that value co-creation mechanisms differ between business-to-business and customer-to-customer digital service types. We identify five mechanisms to support value co-creation in the design of digital services: (1) Social use, (2) Customer orientation and decision making, (3) Service experience, (4) Service use context, and (5) Customer values and goals. We claim that firms can readily utilize these mechanisms to improve their customers’ service experiences.
|
|
| 30. |
- Usunobun, Inegbedion, et al.
(författare)
-
Cultural Values’ Influences on Users’ Preferences for Gamification Techniques
- 2019
-
Ingår i: International Conference on Information Systems.
-
Konferensbidrag (refereegranskat)abstract
- Gamification techniques such as badges, levels, roles, are widely adopted in information systems (IS). Though researchers have noted that cultural values may influence users’ usage of IS, there is a lack of research regarding the relationship of cultural values and gamification techniques. Our study aims to contribute to this area. We propose that users’ cultural values may influence how they are motivated and further influence their preferences toward specific gamification techniques. In this research in progress, we review cultural values, examine the currently adopted gamification techniques, and then propose how cultural values influence users’ preferences toward specific gamification techniques. We encourage designers to cater the adoption of gamification techniques in IS according to the users’ cultural values, and researchers may further investigate the relation-ship between culture and gamification techniques. We propose a research agenda to investigate IS users’ preferences toward different gamification techniques through an experiment with cultural values primed and a survey with participants from different cultural settings.
|
|
| 31. |
- Wang, Le, et al.
(författare)
-
Retaining users after privacy invasions: The roles of institutional privacy assurances and threat-coping appraisal in mitigating privacy concerns
- 2019
-
Ingår i: Information Technology and People. - 0959-3845. ; 32:6, s. 1679-1703
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose The purpose of this paper is to facilitate understanding of how to mitigate the privacy concerns of users who have experienced privacy invasions. Design/methodology/approach Drawing on the communication privacy management theory, the authors developed a model suggesting that privacy concerns form through a cognitive process involving threat-coping appraisals, institutional privacy assurances and privacy experiences. The model was tested using data from an empirical survey with 913 randomly selected social media users. Findings Privacy concerns are jointly determined by perceived privacy risks and privacy self-efficacy. The perceived effectiveness of institutional privacy assurances in terms of established privacy policies and privacy protection technology influences the perceptions of privacy risks and privacy self-efficacy. More specifically, privacy invasion experiences are negatively associated with the perceived effectiveness of institutional privacy assurances. Research limitations/implications Privacy concerns are conceptualized as general concerns that reflect an individual’s worry about the possible loss of private information. The specific types of private information were not differentiated. Originality/value This paper is among the first to clarify the specific mechanisms through which privacy invasion experiences influence privacy concerns. Privacy concerns have long been viewed as resulting from individual actions. The study contributes to literature by linking privacy concerns with institutional privacy practice.
|
|
| 32. |
- Wang, Yixin, et al.
(författare)
-
Smooth muscle cell recruitment to lymphatic vessels requires PDGFB and impacts vessel size but not identity
- 2017
-
Ingår i: Development. - : COMPANY OF BIOLOGISTS LTD. - 0950-1991 .- 1477-9129. ; 144:19, s. 3590-3601
-
Tidskriftsartikel (refereegranskat)abstract
- Tissue fluid drains through blind-ended lymphatic capillaries, via smooth muscle cell (SMC)-covered collecting vessels into venous circulation. Both defective SMC recruitment to collecting vessels and ectopic recruitment to lymphatic capillaries are thought to contribute to vessel failure, leading to lymphedema. However, mechanisms controlling lymphatic SMC recruitment and its role in vessel maturation are unknown. Here, we demonstrate that platelet-derived growth factor B (PDGFB) regulates lymphatic SMC recruitment in multiple vascular beds. PDGFB is selectively expressed by lymphatic endothelial cells (LECs) of collecting vessels. LEC-specific deletion of Pdgfb prevented SMC recruitment causing dilation and failure of pulsatile contraction of collecting vessels. However, vessel remodelling and identity were unaffected. Unexpectedly, Pdgfb overexpression in LECs did not induce SMC recruitment to capillaries. This was explained by the demonstrated requirement of PDGFB extracellular matrix (ECM) retention for lymphatic SMC recruitment, and the low presence of PDGFB-binding ECM components around lymphatic capillaries. These results demonstrate the requirement of LEC-autonomous PDGFB expression and retention for SMC recruitment to lymphatic vessels, and suggest an ECM-controlled checkpoint that prevents SMC investment of capillaries, which is a common feature in lymphedematous skin.
|
|
| 33. |
- Xiong, Binyu, et al.
(författare)
-
An Enhanced Equivalent Circuit Model of Vanadium Redox Flow Battery Energy Storage Systems Considering Thermal Effects
- 2019
-
Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 7, s. 162297-162308
-
Tidskriftsartikel (refereegranskat)abstract
- Thermal issue is one of the major concerns for safe, reliable, and efficient operation of the vanadium redox flow battery (VRB) energy storage systems. During the design of the operational strategy for a grid-connected VRB system, a suitable mathematical model is needed to predict the dynamic behaviors under various operating conditions. However, conventional VRB models usually neglect the impact of temperature variations on system performance. This work develops an enhanced VRB model with the consideration of the coupling effects between the electrochemical and the thermal behaviors. The proposed model consists of two equivalent circuits. First, the electrochemical behaviors of the VRB are modeled by a second-order RC network taking account of the effects of concentration variation of the vanadium ions and the electrochemical activation. Second, a third-order Cauer network is used to model the heat transfer process in the VRB system, and the dynamic thermal behaviors of stacks, pipes and heat exchangers are characterized. Well-designed experiments and particle swarm optimization algorithm are use to identify the parametric values of the developed model. The proposed modeling method was validated experimentally using a 5kW/3kWh VRB platform, and the results show that the model is capable of accurately predicting the VRB performance under variable temperature conditions. The developed coupled electro-thermal model is then used for simulating and analyzing the performance of a VRB system operated in conjunction with a wind power plant under real-world conditions.
|
|
| 34. |
- Yang, Jiabao, et al.
(författare)
-
Inhibiting metal-inward diffusion-induced degradation through strong chemical coordination toward stable and efficient inverted perovskite solar cells
- 2022
-
Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 15:5, s. 2154-2163
-
Tidskriftsartikel (refereegranskat)abstract
- The inward diffusion of metal electrodes is one of the main reasons for the deterioration of the long-term device stability of perovskite solar cells (PSCs). Thus, herein, we adopt a simple additive engineering strategy to modify the barrier material bathocuproine (BCP) with 1,3,5-triazine-2,4,6-trithiol trisodium salt (TTTS). Different from the traditional physical blocking strategies, TTTS could prevent the metal electrodes (e.g., gold, silver, and copper) from diffusing inward through the strong chemical coordination between TTTS and the metal electrode. The TTTS additive also improved the conductivity and band structure of BCP, thus enhancing the ability of BCP to extract electrons from the perovskite layer to the electrode. Consequently, the inverted device modified with TTTS exhibited a high efficiency of 22.59%, which is among the highest efficiencies reported to date for inverted PSCs. More importantly, it showed excellent operational, ambient, and thermal stability. The target device maintained its initial efficiency with no loss under continuous one-sun illumination at maximum power point tracking after 1000 h (the champion device), 91% in air (50% +/- 5% RH) for 5000 h, and 93% after heating at 85 degrees C for 1500 h (average efficiency from ten devices).
|
|
| 35. |
- Yang, Jiabao, et al.
(författare)
-
Overcome Low Intrinsic Conductivity of NiOx Through Triazinyl Modification for Highly Efficient and Stable Inverted Perovskite Solar Cells
- 2022
-
Ingår i: Solar RRL. - : John Wiley & Sons. - 2367-198X. ; 6:9
-
Tidskriftsartikel (refereegranskat)abstract
- Nickel oxide (NiOx) is a promising hole transport material in inverted organic-inorganic metal halide perovskite solar cells. However, its low intrinsic conductivity hinders its further improvement in device performance. Here, we employ a trimercapto-s-triazine trisodium salt (TTTS) as a chelating agent of Ni2+ in the NiOx layer to improve its conductivity. Due to the electron-deficient triazine ring, the TTTS complexes with Ni2+ in NiOx via a strong Ni2+-N coordination bond and increases the ratio of Ni3+:Ni2+. The increased Ni3+ concentration adjusts the band structure of NiOx, thus enhancing hole density and mobility, eventually improving the intrinsic conductivity of NiOx. As a result, the device with TTTS modification displays a champion power conversion efficiency (PCE) of 22.81%. The encapsulated device based on a modified-NiOx layer maintains 94% of its initial power output at the maximum power point and continuous one-sun illumination for 1000 h at 45 degrees C. In addition, the unencapsulated target devices also maintain 92% at 60 +/- 5% relative humidity and 25 degrees C in the air for 5000 h; and 91% at 85 degrees C in a nitrogen atmosphere for 1000 h. The research provides an effective strategy to enhance PCE and stability of inverted PSCs via modifying NiOx films with triazine molecule.
|
|
| 36. |
- Yang, Shangchen, et al.
(författare)
-
Genomic investigation of the Chinese alligator reveals wild-extinct genetic diversity and genomic consequences of their continuous decline
- 2023
-
Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 23:1, s. 294-311
-
Tidskriftsartikel (refereegranskat)abstract
- Critically endangered species are usually restricted to small and isolated populations. High inbreeding without gene flow among populations further aggravates their threatened condition and reduces the likelihood of their long-term survival. Chinese alligator (Alligator sinensis) is one of the most endangered crocodiles in the world and has experienced a continuous decline over the past c. 1 million years. In order to identify the genetic status of the remaining populations and aid conservation efforts, we assembled the first high-quality chromosome-level genome of Chinese alligator and explored the genomic characteristics of three extant breeding populations. Our analyses revealed the existence of at least three genetically distinct populations, comprising two breeding populations in China (Changxing and Xuancheng) and one breeding population in an American wildlife refuge. The American population does not belong to the last two populations of its native range (Xuancheng and Changxing), thus representing genetic diversity extinct in the wild and provides future opportunities for genetic rescue. Moreover, the effective population size of these three populations has been continuously declining over the past 20 ka. Consistent with this decline, the species shows extremely low genetic diversity, a large proportion of long runs of homozygous fragments, and mutational load across the genome. Finally, to provide genomic insights for future breeding management and conservation, we assessed the feasibility of mixing extant populations based on the likelihood of introducing new deleterious alleles and signatures of local adaptation. Overall, this study provides a valuable genomic resource and important genomic insights into the ecology, evolution, and conservation of critically endangered alligators.
|
|
| 37. |
- Zhang, Yixin
(författare)
-
Balancing food availability and hydrodynamic constraint : phenotypic plasticity and growth in Simulium noelleri blackfly larvae.
- 2006
-
Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 147:1, s. 39-46
-
Tidskriftsartikel (refereegranskat)abstract
- Organisms through phenotypic plasticity can cope with multiple changed environmental conditions. Theory predicts that animals in streams and rivers should be able to balance demands of the needs to obtain food efficiently and to adjust response to hydrodynamic variability. This study examined effects of variations in food availability and current velocity on the feeding structure and growth rate of Simulium noelleri blackfly larvae. The larvae developed larger labral fans and more rays under slow current and low food regimes than in fast current and high food conditions. In both fast and slow current regimes, growth rates were higher and development periods to the final-instar stage were shorter in high food treatments. The estimated flux rates of food particles through labral fans under high food treatments for both fast and slow current regimes were higher than those under low food treatments. Although both food and current velocity appeared to have selected for flexibility of feeding structure and growth rate, food availability was a more important factor for phenotypic and developmental plasticity than current velocity. The results indicate a strong link between environmental changes in food availability and current velocity, phenotypic plasticity, and growth rate of S. noelleri. This study suggests that plasticity of ecomorphs with macroevolutionary significance may play a role in the early evolutionary stages of blackfly larvae.
|
|
| 38. |
- Zhang, Yixin, et al.
(författare)
-
Do users really care about privacy? Mobile applications’ popularity, user satisfaction, and permission requests
- 2020
-
Ingår i: European Conference on Information Systems (ECIS), 2020.
-
Konferensbidrag (refereegranskat)abstract
- In this research in progress, we investigated the effects of mobile applications’ permission requests and their popularity among users. We collected data from 7959 Android apps on the Android app market across different application categories, and examined apps’ permission requests, number of downloads, and users’ ratings. We noted that permission requests that have privacy intrusion concerns influence apps ratings to different extents. For requests that have privacy intrusion concerns and can be easily noted by users, such as requests to camera, users increase the number of unfavourable one star rating’s. For requests that have privacy intrusion concerns but cannot be easily noted by users, such as request to read contacts, the influences on user ratings are not significant. The findings reveal that users are at a disadvantaged position as they may not be aware of privacy intrusions when the request involves actions by the app that cannot be observed by users. To further understand users’ decision process, we plan to conduct interviews and an experiment, in which we will prime users’ privacy concerns.
|
|
| 39. |
- Zhang, Yixin, et al.
(författare)
-
How do interruptions affect user contributions on social commerce?
- 2020
-
Ingår i: Information Systems Journal. - : Wiley. - 1350-1917 .- 1365-2575. ; 30:3, s. 535-565
-
Tidskriftsartikel (refereegranskat)abstract
- Social commerce is an extension of e‐commerce, in which social media is leveraged to promote user contributions. Our study asks how interruptions in relation to interface design influence two types of user contributions: creating shared content and appreciating others' content. We use two interface designs, pagination and infinite scrolling, to manipulate the extent of interruptions to social commerce users. On the basis of the capacity theory of attention, we develop five hypotheses. We empirically test our model using a lab experiment and a field study to show that interruptions reduce users' content appreciation but increase their content creation and that user characteristics moderate these effects. The theoretical and practical contributions of our study are discussed.
|
|
| 40. |
- Zhang, Yixin
(författare)
-
Using Arduino in Teaching Digital Infrastructure among Students with Diverse Technical Backgrounds
- 2022
-
Ingår i: Pacific Asia Conference on Information Systems.
-
Konferensbidrag (refereegranskat)abstract
- Prior literature on using Arduino in university teaching mainly discussed integrating Arduino into an engineering course and students may have engineering backgrounds. In Information Systems (IS) curriculum, some courses do not emphasize on technical aspects, and students have diverse technical backgrounds. The workshop was designed to encourage learning by doing. Students were asked to develop prototypes to address a real world problem. They could use Arduino microcontroller, sensors (such as ultrasonic sensor to sense distance of objects), and devices such as LED lights, fans. Students were very engaged in the intensive workshop, and the outcome is positive. The study sheds light on integrating Arduino into courses that do not focus on engineering but aim to help students gain understanding of technical concepts such as software, hardware, input, output, and control. Students also learn about design and prototyping through the workshop.
|
|
| 41. |
- Zhang, Yixin, et al.
(författare)
-
What to post? Understanding engagement cultivation in microblogging with big data-driven theory building
- 2023
-
Ingår i: International Journal of Information Management. - : Elsevier BV. - 0268-4012. ; 71
-
Tidskriftsartikel (refereegranskat)abstract
- This paper examines how alternative food networks (AFNs) cultivate engagement on a social media platform. Using the method proposed in Kar and Dwivedi (2020) and Berente et al. (2019), we contribute to theory through combining exploratory text analysis with model testing. Using the theoretical lens of relationship cultivation and social media engagement, we collected 55,358 original Weibo posts by 90 farms and other AFN participants in China and used Latent Dirichlet Allocation (LDA) modeling for topic analysis. We then used the literature to map the topics with constructs and developed a theoretical model. To validate the theoretical model, a panel dataset was constructed on Weibo account and year level, with Chinese city-level yearly economic data included as control variables. A fixed effects panel data regression analysis was performed. The empirical results revealed that posts centered on openness/disclosure, sharing of tasks, and knowledge sharing result in positive levels of social media engagement. Posting about irrelevant information and advertising that uses repetitive wording in multiple posts had negative effects on engagement. Our findings suggest that cultivating engagement requires different relationship strategies, and social media platforms should be leveraged according to the context and the purpose of the social cause. Our research is also among the early studies that use both big data analysis of large quantities of textual data and model validation for theoretical insights.
|
|
| 42. |
- Zhang, Zhao Yang, et al.
(författare)
-
Photochemical Phase Transitions Enable Coharvesting of Photon Energy and Ambient Heat for Energetic Molecular Solar Thermal Batteries That Upgrade Thermal Energy
- 2020
-
Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 142:28, s. 12256-12264
-
Tidskriftsartikel (refereegranskat)abstract
- Discovering physicochemical principles for simultaneous harvesting of multiform energy from the environment will advance current sustainable energy technologies. Here we explore photochemical phase transitions - a photochemistry-thermophysics coupled regime - for coharvesting of solar and thermal energy. In particular, we show that photon energy and ambient heat can be stored together and released on demand as high-temperature heat, enabled by room-temperature photochemical crystal↔liquid transitions of engineered molecular photoswitches. Integrating the two forms of energy in single-component molecular materials is capable of providing energy capacity beyond that of traditional solar or thermal energy storage systems based solely on molecular photoisomerization or phase change, respectively. Significantly, the ambient heat that is harvested during photochemical melting into liquid of the low-melting-point, metastable isomer can be released as high-temperature heat by recrystallization of the high-melting-point, parent isomer. This reveals that photon energy drives the upgrading of thermal energy in such a hybrid energy system. Rationally designed small-molecule azo switches achieve high gravimetric energy densities of 0.3-0.4 MJ/kg with long-term storage stability. Rechargeable solar thermal battery devices are fabricated, which upon light triggering provide gravimetric power density of about 2.7 kW/kg and temperature increases of >20 °C in ambient environment. We further show their use as deicing coatings. Our work demonstrates a new concept of energy utilization - combining solar energy and low-grade heat into higher-grade heat - which unlocks the possibility of developing sustainable energy systems powered by a combination of natural sunlight and ambient heat.
|
|
