| 1. |
- Li, Gang, et al.
(författare)
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Selective Electrochemical Alkaline Seawater Oxidation Catalyzed by Cobalt Carbonate Hydroxide Nanorod Arrays with Sequential Proton-Electron Transfer Properties
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:2, s. 905-913
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Tidskriftsartikel (refereegranskat)abstract
- Seawater oxygen evolution is one of the promising energy conversion technologies for large-scale renewable energy storage. It requires efficient catalysts to accelerate the oxygen evolution reaction (OER) for sustained water oxidation, avoiding chlorine evolution under acidic conditions or hypochlorite formation in alkaline solutions. Conventional metal oxide-based OER catalysts follow the adsorbate evolution mechanism that involves concerted proton-electron transfer steps at the active sites. Thus, on the scale of reversible hydrogen electrode, their catalytic activity is independent of the pH of electrolytes. In the present study, nanostructured cobalt carbonate hydroxide (CoCH) with sequential proton-electron transfer properties was tested as a catalyst for seawater oxygen evolution. CoCH exhibited pH-dependent water oxidation activities, thereby providing larger potential and current operating windows for selective water oxidation compared to the catalysts with pH-independent OER activities. The operating window can be further expanded by increasing the pH of the electrolyte.
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| 2. |
- Li, Yingzheng, et al.
(författare)
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Influence of O-O formation pathways and charge transfer mediator on lipid bilayer membrane-like photoanodes for water oxidation
- 2024
-
Ingår i: Journal of Energy Chemistry. - : Elsevier. - 2095-4956 .- 2096-885X. ; 93, s. 526-537
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Tidskriftsartikel (refereegranskat)abstract
- Inspired by the function of crucial components in photosystem II (PSII), electrochemical and dyesensitized photoelectrochemical (DSPEC) water oxidation devices were constructed by the selfassembly of well-designed amphipathic Ru(bda)-based catalysts (bda = 2,2'-bipyrdine-6,6'-dicarbonoxyl acid) and aliphatic chain decorated electrode surfaces, forming lipid bilayer membrane (LBM)-like structures. The Ru(bda) catalysts on electrode-supported LBM films demonstrated remarkable water oxidation performance with different O-O formation mechanisms. However, compared to the slow charge transfer process, the O-O formation pathways did not determine the PEC water oxidation efficiency of the dyesensitized photoanodes, and the different reaction rates for similar catalysts with different catalytic paths did not determine the PEC performance of the DSPECs. Instead, charge transfer plays a decisive role in the PEC water oxidation rate. When an indolo[3,2-b] carbazole derivative was introduced between the Ru (bda) catalysts and aliphatic chain-modified photosensitizer in LBM films, serving as a charge transfer mediator for the tyrosine-histidine pair in PSII, the PEC water oxidation performance of the corresponding photoanodes was dramatically enhanced.
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| 3. |
- Liu, Chang, et al.
(författare)
-
A dendritic Sb2Se3/In2S3 heterojunction nanorod array photocathode decorated with a MoSx catalyst for efficient solar hydrogen evolution
- 2020
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 8:44, s. 23385-23394
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Tidskriftsartikel (refereegranskat)abstract
- Developing cost-effective photocathodes that show desirable performance for use in commercial photoelectrochemical water splitting devices remains a fundamental and practical challenge. Sb2Se3 semiconductors satisfy most of the demands expected for an ideal highly efficient photocathode, including favorable cost and optoelectronic properties. Herein, we have demonstrated outstanding photoelectrodes using a noble-metal-free catalyst, namely, a MoSx-decorated low-cost Sb2Se3/In2S3 heterojunction, as the photocathode. This enabled a maximum photocurrent density of up to -27 mA cm(-2) (0 V vs. RHE, 100 mW cm(-2), AM 1.5G filter) with a remarkable half solar-to-hydrogen conversion efficiency (STH) of 2.6%, obtained via decreasing charge recombination and accelerating charge transfer through morphological optimization of the In2S3 layer.
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| 4. |
- Zhao, Yilong, et al.
(författare)
-
Efficient urea electrosynthesis from carbon dioxide and nitrate via alternating Cu–W bimetallic C–N coupling sites
- 2023
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Electrocatalytic urea synthesis is an emerging alternative technology to the traditional energy-intensive industrial urea synthesis protocol. Novel strategies are urgently needed to promote the electrocatalytic C–N coupling process and inhibit the side reactions. Here, we report a CuWO4 catalyst with native bimetallic sites that achieves a high urea production rate (98.5 ± 3.2 μg h−1 mg−1cat) for the co-reduction of CO2 and NO3− with a high Faradaic efficiency (70.1 ± 2.4%) at −0.2 V versus the reversible hydrogen electrode. Mechanistic studies demonstrated that the combination of stable intermediates of *NO2 and *CO increases the probability of C–N coupling and reduces the potential barrier, resulting in high Faradaic efficiency and low overpotential. This study provides a new perspective on achieving efficient urea electrosynthesis by stabilizing the key reaction intermediates, which may guide the design of other electrochemical systems for high-value C–N bond-containing chemicals.
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| 5. |
- Li, Wenlong, et al.
(författare)
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Enantiospecific photoresponse of sterically hindered diarylethenes for chiroptical switches and photomemories
- 2015
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Light-driven transcription, replication and enzyme catalysis are critically dependent upon a delicate transfer between molecular and supramolecular chirality. Chemists have well realized the impressive stereospecificity over many thermally accessible cycloaddition with chiral catalysts, but making light work in the enantiomer control of diarylethene photocyclization has proved to be more challenging. Here, we report a unique sterically hindered diarylethene (BBTE) system with absolute enantiospecific photocyclization and cycloreversion. Moreover, we have fully separated all the five thermally stable isomers, consisting of one achiral parallel conformer, one pair of anti-parallel ring-open enantiomers, and another pair of ring-closed enantiomers, whose absolute chiral configurations are entirely elucidated by single X-ray crystallographic analyses. The photo-responsive feature exhibits a reversible, complete enantio-control transformation without racemism, offering an unrivaled unimolecular enantiospecific platform for potential applications as bistable chiroptical switches and all-photonic photomemories with optical rotation as non-destructive readout.
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| 6. |
- Li, Yingzheng, et al.
(författare)
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Switching the O-O Bond Formation Pathways of Ru-pda Water Oxidation Catalyst by Third Coordination Sphere Engineering
- 2021
-
Ingår i: RESEARCH. - : American Association for the Advancement of Science (AAAS). - 2639-5274. ; 2021
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Tidskriftsartikel (refereegranskat)abstract
- Water oxidation is a vital anodic reaction for renewable fuel generation via electrochemical- and photoelectrochemical-driven water splitting or CO2 reduction. Ruthenium complexes, such as Ru-bda family, have been shown as highly efficient water-oxidation catalysts (WOCs), particularly when they undergo a bimolecular O-O bond formation pathway. In this study, a novel Ru(pda)-type (pda(2-) = 1,10-phenanthroline-2,9-dicarboxylate) molecular WOC with 4-vinylpyridine axial ligands was immobilized on the glassy carbon electrode surface by electrochemical polymerization. Electrochemical kinetic studies revealed that this homocoupling polymer catalyzes water oxidation through a bimolecular radical coupling pathway, where interaction between two Ru(pda)-oxyl moieties (I2M) forms the O-O bond. The calculated barrier of the I2M pathway by density-functional theory (DFT) is significantly lower than the barrier of a water nucleophilic attack (WNA) pathway. By using this polymerization strategy, the Ru centers are brought closer in the distance, and the O-O bond formation pathway by the Ru (pda) catalyst is switched from WNA in a homogeneous molecular catalytic system to I2M in the polymerized film, providing some deep insights into the importance of third coordination sphere engineering of the water oxidation catalyst.
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| 7. |
- Wu, Yue, et al.
(författare)
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Photoswitching between black and colourless spectra exhibits resettable spatiotemporal logic
- 2016
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Ingår i: Materials Horizons. - : Royal Society of Chemistry. - 2051-6347 .- 2051-6355. ; 3:2, s. 124-129
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Tidskriftsartikel (refereegranskat)abstract
- Logic is the key to computing. Traditionally, logic devices have been fabricated by the top-down approach, whose dimensions are drastically limited. The ultimate goal is to use molecular tailorability to design logics using the "bottom-up'' approach. Here we report an unprecedented photochromic molecule that undergoes unimolecular logic switching when excited anywhere in the entire UV-visible spectrum, thus a bottom-up, all-photonic, molecular logic gate. Specifically, these molecular photonic logics embedded in the polymer thin films function as the "AND'' or "OR'' gate at different temporal responses. To achieve high information-processing density, moreover, a ternary flip-flap-flop gate is realized in the molecular logic because the fact that this photochromic molecule can be photoswitched anywhere in its UV-vis spectrum enabled three different lasers (532, 473, and 561 nm) as the inputs to deliver the complex logic optical outputs.
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| 8. |
- Chen, Shangjun, et al.
(författare)
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Substitution effect on the photochromic properties of benzo[b]thiophene-1,1-dioxide based diarylethenes
- 2015
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 5:106, s. 87626-87634
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Tidskriftsartikel (refereegranskat)abstract
- Benzo[b]thiophene-1,1-dioxide based diarylethenes (DAEs), BTT-1 to BTT-4, containing methyl, phenyl, formyl and triphenylamine groups at the 5,5'-position of the thiophene rings have been developed for gaining an insight into the substituent effect on the absorption and photochromic properties. Electron-donating substituents, such as phenyl and triphenylamine groups, are found to be effective at shifting the absorption band to a longer wavelength and decreasing the cyclization quantum yield. The electron-withdrawing formyl group can increase the cyclization quantum yield, but it reduces the thermal stability of the ring-closed isomer to some extent. BTT-4 bearing a triphenylamine group shows the poorest fatigue resistance among these four compounds, which is possibly due to the larger extended pi-conjugation length in the ring-closed isomer. BTT-2 bearing a phenyl unit undergoes typical photochromic reaction not only in solution, but also in PMMA thin film and in bulky crystals with excellent fatigue resistance and thermal stability.
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| 9. |
- Li, Fusheng, et al.
(författare)
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Device Fabrication for Water Oxidation, Hydrogen Generation, and CO2 Reduction via Molecular Engineering
- 2018
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Ingår i: Joule. - : CELL PRESS. - 2542-4351. ; 2:1, s. 36-60
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Tidskriftsartikel (refereegranskat)abstract
- Research on the storage of solar energy in terms of hydrogen or carbon-based fuels by using sunlight to split water or to reduce CO2, respectively, has gained significant attention in recent years. Among reported water-splitting systems, one approach has focused on hybrid systems with molecular catalysts or molecular light-harvesting systems that are combined with nanostructured materials. In this perspective we summarize recent developments in operation and fabrication strategies for various water-splitting devices constructed from electrodes (electrochemical cells) or photoelectrodes (photoelectrochemical cells) using molecular engineering. We also provide insights into the factors that influence device efficiency and stability, and provide guidelines for future fabrication strategies for more advanced devices.
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| 10. |
- Li, Nan, et al.
(författare)
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Study of the influence of the characteristics of loose residual coal on the spontaneous combustion of coal gob
- 2020
-
Ingår i: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 8:3, s. 689-701
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Tidskriftsartikel (refereegranskat)abstract
- Mine fires are becoming a serious issue as the intensity of mining increases, especially in deep mines. Loose coal gob has a hidden ignition location and a high possibility of spontaneous combustion, which makes fire prevention difficult. Therefore, based on the theory of gas seepage and the characteristics of loose coal, a model of air leakage and spontaneous combustion in gob is established in this paper. Using working face #10414 in the Yangliu coal mine as an example, the relationship between the three spontaneous coal combustion (CSC) zones and the three stress zones is analyzed and verified by combining a FLAC3D simulation with field monitoring. In addition, the influence of advancing speed on the CSC is discussed, and suggestions for fire prevention are presented. The results show that the variation in the calorific value of the CSC with increasing degree of looseness of the residual coal in the gob forms an arch‐shape. There is a one‐to‐one relationship between the distribution of the three stress zones and the three CSC zones. In addition, as the advancing speed increases, the contact time between the loose coal body and the air decreases and the possibility of CSC decreases. This study provides a scientific basis for fire prevention and control in mines.
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| 11. |
- Li, Qishuang, et al.
(författare)
-
Identification of the cytochrome P450s responsible for the biosynthesis of two types of aporphine alkaloids and their de novo biosynthesis in yeast
- 2024
-
Ingår i: Journal of Integrative Plant Biology. - 1672-9072 .- 1744-7909. ; In Press
-
Tidskriftsartikel (refereegranskat)abstract
- Aporphine alkaloids have diverse pharmacological activities; however, our understanding of their biosynthesis is relatively limited. Previous studies have classified aporphine alkaloids into two categories based on the configuration and number of substituents of the D-ring and have proposed preliminary biosynthetic pathways for each category. In this study, we identified two specific cytochrome P450 enzymes (CYP80G6 and CYP80Q5) with distinct activities toward (S)-configured and (R)-configured substrates from the herbaceous perennial vine Stephania tetrandra, shedding light on the biosynthetic mechanisms and stereochemical features of these two aporphine alkaloid categories. Additionally, we characterized two CYP719C enzymes (CYP719C3 and CYP719C4) that catalyzed the formation of the methylenedioxy bridge, an essential pharmacophoric group, on the A- and D-rings, respectively, of aporphine alkaloids. Leveraging the functional characterization of these crucial cytochrome P450 enzymes, we reconstructed the biosynthetic pathways for the two types of aporphine alkaloids in budding yeast (Saccharomyces cerevisiae) for the de novo production of compounds such as (R)-glaziovine, (S)-glaziovine, and magnoflorine. This study provides key insight into the biosynthesis of aporphine alkaloids and lays a foundation for producing these valuable compounds through synthetic biology.
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| 12. |
- Li, Wenlong, et al.
(författare)
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A bio-inspired coordination polymer as outstanding water oxidation catalyst via second coordination sphere engineering
- 2019
-
Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- First-row transition metal-based catalysts have been developed for the oxygen evolution reaction (OER) during the past years, however, such catalysts typically operate at overpotentials (eta) significantly above thermodynamic requirements. Here, we report an iron/ nickel terephthalate coordination polymer on nickel form (NiFeCP/NF) as catalyst for OER, in which both coordinated and uncoordinated carboxylates were maintained after electrolysis. NiFeCP/NF exhibits outstanding electro-catalytic OER activity with a low overpotential of 188 mV at 10 mA cm(-2) in 1.0 KOH, with a small Tafel slope and excellent stability. The pH-independent OER activity of NiFeCP/NF on the reversible hydrogen electrode scale suggests that a concerted proton-coupled electron transfer (c-PET) process is the rate-determining step (RDS) during water oxidation. Deuterium kinetic isotope effects, proton inventory studies and atom-proton-transfer measurements indicate that the uncoordinated carboxylates are serving as the proton transfer relays, with a similar function as amino acid residues in photosystem II (PSII), accelerating the proton-transfer rate.
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| 13. |
- Li, Wenlong, et al.
(författare)
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Sterically hindered diarylethenes with a benzobis(thiadiazole) bridge : photochemical and kinetic studies
- 2015
-
Ingår i: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7526 .- 2050-7534. ; 3:33, s. 8665-8674
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Tidskriftsartikel (refereegranskat)abstract
- Four rationally designed diarylethenes (DAEs) 1-4 with a benzobis(thiadiazole) bridge are specifically designed for gaining insights into steric effects on photochromic performances. It is shown that, upon increasing steric hindrance, the exchanging rate between two main conformers in the ring-open form gradually slows down, offering the opportunity for isolating photoactive anti-parallel conformers. Impressively, the separated anti-parallel conformer shows high cyclization quantum yields over the unresolved common DAEs. The typical donor-pi-acceptor (D-pi-A) feature in ring-open DAEs 1-4 endows their prominent fluorescence, which can be conveniently modulated by photocyclization. In the ring-closed form, the excess steric hindrance is found to seriously disrupt the thermal bistability, and particularly 3c fades quickly with a half-life of several hours at ambient temperature. In contrast, both 1c and 2c exhibit excellent stability, which originates from the stabilization effects of intramolecular hydrogen bonds. This work demonstrates the steric effects on the photochemical and kinetic behaviors of DAEs, providing a unique approach to develop photochromic DAEs with high photosensitivity.
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| 14. |
- Li, Xin, et al.
(författare)
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Theoretical insight into the enhanced hindrance, thermal stability and optical properties of diarylethene with a benzobis(thiadiazole) bridge and benzothiophene rings
- 2016
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Ingår i: Dyes and pigments. - : ELSEVIER SCI LTD. - 0143-7208 .- 1873-3743. ; 125, s. 348-355
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Tidskriftsartikel (refereegranskat)abstract
- To rationalize the effects of intramolecular steric hindrance on the performance of diarylethene photoswitches, we here present a density functional theory study on the thermal bistability and optical properties of a photochromic diarylethene BBTE consisting of a benzobis(thiadiazole) bridge and benzothiophene rings, in which prominent steric hindrance exists owing to the extended structures of is-conjugated groups. Our calculations not only provide rational explanations for the isolation of enantiopure anti-parallel conformers of the open-ring isomer, but also elucidate the detailed pathway of a two-step ground-state ring-opening process, where the thermal stability of the closed-ring isomer is guaranteed by an overall free energy barrier of around 113 kJ mol(-1) (27 kcal mol(-1)). In addition, the tunable intramolecular charge transfer of the donor acceptor structure formed by the benzobis(thiadiazole) bridge and the bulky benzothiophene rings is also addressed within time-dependent density functional theory. Charge transfer excitations in the open- and the closed-ring isomers are characterized as long-range and medium-range, respectively. We show that the diarylethene derivative under investigation can serve as a promising platform for future development of optoelectronic materials.
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| 15. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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| 16. |
- Ma, Shengyu, et al.
(författare)
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Metal–Molybdenum Sulfide Nanosheet Arrays Prepared by Anion Exchange as Catalysts for Hydrogen Evolution
- 2020
-
Ingår i: Energy Technology. - : Wiley-VCH Verlag. - 2194-4288 .- 2194-4296. ; 8:10
-
Tidskriftsartikel (refereegranskat)abstract
- Metal–molybdenum sulfide (MMoSx)-based catalysts exhibit good performance over a wide pH range toward hydrogen evolution with relatively low overvoltage requirements. Therefore, they are considered as suitable alternatives to Pt as catalysts for hydrogen evolution reaction. Herein, self-supported amorphous CuMoSx and NiMoSx nanosheet arrays are prepared on copper foam (CF) and nickel foam (NF), respectively, through an anion-exchange strategy. CF and NF are first converted into CuTCNQ and NiTCNQ nanowire arrays (TCNQ = tetracyanoquinodimethane), which are then in situ reacted with (NH4)2MoS4 solution to generate amorphous CuMoSx/CF and NiMoSx/NF nanosheets, respectively, as efficient electrocatalysts for H2 generation. NiMoSx/NF exhibits a superior catalytic activity to CuMoSx/CF in 0.5 m H2SO4 solution, as CuMoSx/CF requires overpotentials (η) of 213 and 275 mV to obtain current densities of 10 and 50 mA cm−2, respectively, whereas NiMoSx/NF only requires η of 174 and 248 mV to receive the same current densities, respectively. Furthermore, these electrodes exhibit considerable long-term electrochemical durability. Herein, an effective and easy-to-operate strategy for the construction of self-supported metal–molybdenum sulfide nanosheet arrays films toward a highly efficient electrochemical hydrogen generation reaction is provided.
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| 17. |
- Yang, Hao, et al.
(författare)
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Improving the performance of water splitting electrodes by composite plating with nano-SiO2
- 2018
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Ingår i: Electrochimica Acta. - : Pergamon Press. - 0013-4686 .- 1873-3859. ; 281, s. 60-68
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical splitting of water requires efficient functional electrodes. Herein, we report the fabrication of electrocatalyst consisted of an electrodeposited NiFeP alloy film which was composite plated with nano-SiO2 on nickel foam. The structure and morphology of the film were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the surface area of this NiFeP-SiO2 co-deposition alloy film can be significantly increased after electrochemical etching in a KOH solution. The water splitting properties of the alloy film were evaluated using electrochemistry. By using the NiFeP-SiO2/NF(Etched) as a bifunctional electrode, total water splitting has been demonstrated in a two-electrode cell with a current density of 10 mAcm(-2) at an applied voltage of 1.57 V, which exhibited enhanced water splitting activity in comparison to the analogue cell using the pristine NiFeP/NF electrode.
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| 18. |
- Yang, Hao, et al.
(författare)
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Intramolecular hydroxyl nucleophilic attack pathway by a polymeric water oxidation catalyst with single cobalt sites
- 2022
-
Ingår i: Nature Catalysis. - : Springer Nature. - 2520-1158. ; 5:5, s. 414-429
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Tidskriftsartikel (refereegranskat)abstract
- Exploration of efficient water oxidation catalysts (WOCs) is the primary challenge in conversion of renewable energy into fuels. Here we report a molecularly well-defined heterogeneous WOC with Aza-fused, pi-conjugated, microporous polymer (Aza-CMP) coordinated single cobalt sites (Aza-CMP-Co). The single cobalt sites in Aza-CMP-Co exhibited superior activity under alkaline and near-neutral conditions. Moreover, the molecular nature of the isolated catalytic sites makes Aza-CMP-Co a reliable model for studying the heterogeneous water oxidation mechanism. By a combination of experimental and theoretical results, a pH-dependent nucleophilic attack pathway for O-O bond formation was proposed. Under alkaline conditions, the intramolecular hydroxyl nucleophilic attack (IHNA) process with which the adjacent -OH group nucleophilically attacks Co4+=O was identified as the rate-determining step. This process leads to lower activation energy and accelerated kinetics than those of the intermolecular water nucleophilic attack (WNA) pathway. This study provides significant insights into the crucial function of electrolyte pH in water oxidation catalysis and enhancement of water oxidation activity by regulation of the IHNA pathway.
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| 19. |
- Yang, Wenlong, et al.
(författare)
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Performance improvement and thermomechanical analysis of a novel asymmetrical annular thermoelectric generator
- 2024
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Ingår i: Applied Thermal Engineering. - 1359-4311. ; 237
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Tidskriftsartikel (refereegranskat)abstract
- Enhancing thermoelectric performance hinges on optimizing the geometry of thermoelectric legs. In this study, we present a novel asymmetrical annular thermoelectric generator (ATEG) in which the proportions of P-type and N-type legs are meticulously balanced. We construct a one-dimensional analytical model tailored to this ATEG. Utilizing this model, we derive the relationship governing thermal-electrical impedance matching in an asymmetrical ATEG and formulate a general expression for optimizing the asymmetry coefficient. We explore the influence of various thermal boundary conditions on optimal impedance matching, ideal annular leg parameters, and the optimal asymmetry coefficient. Our findings reveal that thermal boundary conditions significantly affect the optimal load ratio. Furthermore, in comparison to traditional ATEGs, our proposed asymmetrical ATEG with the optimized structure exhibits a remarkable 16.2 % increase in output power while maintaining the same material volume. Additionally, we perform a three-dimensional numerical analysis of the asymmetrical ATEG using Comsol. Our research findings indicate that introducing the asymmetric structure leads to higher maximum thermal stress on the legs. Interestingly, the study of asymmetric thermal boundary conditions highlights that improving heat transfer between the ATEG and the cooler yields higher mechanical reliability compared to enhancing heat transfer between the ATEG and the heat source.
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| 20. |
- Zhao, Li-Chen, et al.
(författare)
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Spin soliton with a negative-positive mass transition
- 2020
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - : AMER PHYSICAL SOC. - 2469-9926 .- 2469-9934. ; 101:4
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Tidskriftsartikel (refereegranskat)abstract
- We obtain a striking spin soliton in a two-component Bose-Einstein condensate and investigate its motions in the presence of a constant force. The initially static spin soliton first moves in a direction opposite to the force and then changes direction, showing an extraordinary ac oscillation. The underlying mechanism is uncovered: the spin soliton can exhibit a periodic transition between negative and positive inertial mass because of a particular relation between its energy and moving velocity. We then develop a quasiparticle model that can account for this extraordinary oscillation. Important implications and possible applications are discussed.
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| 21. |
- Damoiseaux, David, et al.
(författare)
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Population Pharmacokinetic Modelling to Support the Evaluation of Preclinical Pharmacokinetic Experiments with Lorlatinib
- 2022
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 111:2, s. 495-504
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Tidskriftsartikel (refereegranskat)abstract
- The effect of transporters and enzymes on drug pharmacokinetics is increasingly evaluated using genetically modified animals that have these proteins either knocked-out or their human orthologues transgenically expressed. Analysis of pharmacokinetic data obtained in such experiments is typically performed using non-compartmental analysis (NCA), which has limitations such as not being able to identify the PK parameter that is affected by the genetic modification of the enzymes or transporters and the requirement of intense and homogeneous sampling of all subjects. Here we used a compartmental population pharmacokinetic modeling approach using PK data from a series of genetically modified mouse experiments with lorlatinib to extend the results and conclusions from previously reported NCA analyses. A compartmental population pharmacokinetic model was built and physiologically plausible covariates were evaluated for the different mouse strains. With the model, similar effects of the strains on the area under the concentration-time curve (AUC) from 0 to 8 hours were found as for the NCA. Additionally, the differences in AUC between the strains were explained by specific effects on clearance and bioavailability for the strain with human expressing CYP3A4. Finally, effects of multidrug efflux transporters ATP-binding cassette (ABC) sub-family B member 1 (ABCB1) and G member 2 (ABCG2) on brain efflux were quantified. Use of compartmental population PK modeling yielded additional insight into the role of drug-metabolizing enzymes and drug transporters in mouse experiments compared to the NCA. Furthermore, these models allowed analysis of heterogeneous pooled datasets and the sparse organ concentration data in contrast to classical NCA analyses.
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| 22. |
- Damoiseaux, David, et al.
(författare)
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Predictiveness of the Human-CYP3A4-Transgenic Mouse Model (Cyp3aXAV) for Human Drug Exposure of CYP3A4-Metabolized Drugs.
- 2022
-
Ingår i: Pharmaceuticals (Basel, Switzerland). - : MDPI AG. - 1424-8247. ; 15:7
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Tidskriftsartikel (refereegranskat)abstract
- The extrapolation of drug exposure between species remains a challenging step in drug development, contributing to the low success rate of drug approval. As a consequence, extrapolation of toxicology from animal models to humans to evaluate safe, first-in-human (FIH) doses requires high safety margins. We hypothesized that a human-CYP3A4-expressing transgenic (Cyp3aXAV) mouse is a more predictive model for human drug exposure of CYP3A4-metabolized small-molecule drugs. Population pharmacokinetic models based on wild-type (WT) and Cyp3aXAV mouse pharmacokinetic data of oral lorlatinib, brigatinib, ribociclib and fisogatinib were allometrically scaled and compared to human exposure. Extrapolation of the Cyp3aXAV mouse model closely predicted the observed human exposure for lorlatinib and brigatinib with a 1.1-fold and 1.0-fold difference, respectively, compared to a 2.1-fold and 1.9-fold deviation for WT-based extrapolations of lorlatinib and brigatinib, respectively. For ribociclib, the extrapolated WT mouse model gave better predictions with a 1.0-fold deviation compared to a 0.3-fold deviation for the extrapolated Cyp3aXAV mouse model. Due to the lack of a human population pharmacokinetic model for fisogatinib, only median maximum concentration ratios were calculated, resulting in ratios of 1.0 and 0.6 for WT and Cyp3aXAV mice extrapolations, respectively. The more accurate predictions of human exposure in preclinical research based on the Cyp3aXAV mouse model can ultimately result in FIH doses associated with improved safety and efficacy and in higher success rates in drug development.
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| 23. |
- Hoffmann, Thomas J, et al.
(författare)
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Genome-wide association study of prostate-specific antigen levels in 392,522 men identifies new loci and improves cross-ancestry prediction
- 2023
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We conducted a multi-ancestry genome-wide association study of prostate-specific antigen (PSA) levels in 296,754 men (211,342 European ancestry; 58,236 African ancestry; 23,546 Hispanic/Latino; 3,630 Asian ancestry; 96.5% of participants were from the Million Veteran Program). We identified 318 independent genome-wide significant (p≤5e-8) variants, 184 of which were novel. Most demonstrated evidence of replication in an independent cohort (n=95,768). Meta-analyzing discovery and replication (n=392,522) identified 447 variants, of which a further 111 were novel. Out-of-sample variance in PSA explained by our new polygenic risk score reached 16.9% (95% CI=16.1%-17.8%) in European ancestry, 9.5% (95% CI=7.0%-12.2%) in African ancestry, 18.6% (95% CI=15.8%-21.4%) in Hispanic/Latino, and 15.3% (95% CI=12.7%-18.1%) in Asian ancestry, and lower for higher age. Our study highlights how including proportionally more participants from underrepresented populations improves genetic prediction of PSA levels, with potential to personalize prostate cancer screening.
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| 24. |
- Li, Bo, et al.
(författare)
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Thermal management performance improvement of phase change material for autonomous underwater vehicles' battery module by optimizing fin design based on quantitative evaluation method
- 2022
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 46:11, s. 15756-15772
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Tidskriftsartikel (refereegranskat)abstract
- Efficient thermal management of lithium battery modules has become a thorny problem in the development of autonomous underwater vehicles (AUVs), especially under high current discharge. In this article, the fin/phase change material (PCM) composite structure was proposed for AUV's battery thermal management with consideration of natural convection. The temperature behavior of the battery and the melting behavior of PCM were investigated under different key parameters. In addition, the heat transfer mechanism of the melting process of the PCM was revealed. More importantly, the dimensionless temperature control performance (TCP) factor and the dimensionless heat storage performance (HSP) factor were introduced as new criteria to quantitatively evaluate the impact of different design parameters on the battery thermal management performance. The results showed that utilizing fins can significantly accelerate the melting of the PCM. Increasing the number of fins can reduce the temperature of the battery and improve the uniformity of the battery temperature distribution. Compared with the pure PCM, the total time required for PCM melting in the fin/PCM battery thermal management unit with different numbers of fins is reduced by at least 11.5%. The decrease of the time of complete PCM melting is not linearly correlated with the length ratio of fins. The fin number of N = 6, length ratio of R = 0.8, and angle between fins of φ = 36° were identified as the optimal parameters of fin/PCM composite structures. The TCP and HSP were enhanced by 38.1% and 4.54%, respectively. The conclusions of this work can provide reference for the accurate design of fin/PCM composite structures for the thermal management of AUV batteries. Highlights: The fin/phase change material composite structure was introduced for autonomous underwater vehicles' battery thermal management. The temperature and melting behavior were investigated with natural convection. The temperature control performance factor and heat storage performance factor were proposed as new evaluation criteria. Temperature deviation index was used to measure the battery temperature uniformity. The performance was enhanced by optimizing the design parameters of fin.
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| 25. |
- Liu, Wenlong, et al.
(författare)
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On the calculation of electric diffusion coefficient of radiation belt electrons with in situ electric field measurements by THEMIS
- 2016
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 43:3, s. 1023-1030
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Tidskriftsartikel (refereegranskat)abstract
- Based on 7years' observations from Time History of Events and Macroscale Interactions during Substorms (THEMIS), we investigate the statistical distribution of electric field Pc5 ULF wave power under different geomagnetic activities and calculate the radial diffusion coefficient due to electric field, , for outer radiation belt electrons. A simple empirical expression of is also derived. Subsequently, we compare to previous D-LL models and find similar Kp dependence with the model, which is also based on in situ electric field measurements. The absolute value of is constantly higher than , probably due to the limited orbital coverage of CRRES. The differences between and the commonly used and models are significant, especially in Kp dependence and energy dependence. Possible reasons for these differences and their implications are discussed. The diffusion coefficient provided in this paper, which also has energy dependence, will be an important contributor to quantify the radial diffusion process of radiation belt electrons.
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