| 1. |
- Zhang, Lixiu, et al.
(författare)
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Advances in the Application of Perovskite Materials
- 2023
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Ingår i: NANO-MICRO LETTERS. - : SHANGHAI JIAO TONG UNIV PRESS. - 2311-6706. ; 15:1
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Forskningsöversikt (refereegranskat)abstract
- Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices (solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices (artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.
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| 2. |
- Ge, Q., et al.
(författare)
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Active contour evolved by joint probability classification on Riemannian manifold
- 2016
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Ingår i: Signal, Image and Video Processing. - : Springer London. - 1863-1703 .- 1863-1711. ; 10:7, s. 1257-1264
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present an active contour model for image segmentation based on a nonparametric distribution metric without any intensity a priori of the image. A novel nonparametric distance metric, which is called joint probability classification, is established to drive the active contour avoiding the instability induced by multimodal intensity distribution. Considering an image as a Riemannian manifold with spatial and intensity information, the contour evolution is performed on the image manifold by embedding geometric image feature into the active contour model. The experimental results on medical and texture images demonstrate the advantages of the proposed method.
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| 3. |
- Karlsson, Johannes, 1977-
(författare)
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Wireless video sensor network and its applications in digital zoo
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Most computing and communicating devices have been personal computers that were connected to Internet through a fixed network connection. It is believed that future communication devices will not be of this type. Instead the intelligence and communication capability will move into various objects that surround us. This is often referred to as the "Internet of Things" or "Wireless Embedded Internet". This thesis deals with video processing and communication in these types of systems. One application scenario that is dealt with in this thesis is real-time video transmission over wireless ad-hoc networks. Here a set of devices automatically form a network and start to communicate without the need for any previous infrastructure. These devices act as both hosts and routers and can build up large networks where they forward information for each other. We have identified two major problems when sending real-time video over wireless ad-hoc networks. One is the reactive design used by most ad-hoc routing protocols. When nodes move some links that are used in the communication path between the sender and the receiver may disappear. The reactive routing protocols wait until some links on the path breaks and then start to search for a new path. This will lead to long interruptions in packet delivery and does not work well for real-time video transmission. Instead we propose an approach where we identify when a route is about to break and start to search for new routes before this happen. This is called a proactive approach. Another problem is that video codecs are very sensitive for packet losses and at the same time the wireless ad-hoc network is very error prone. The most common way to handle lost packets in video codecs is to periodically insert frames that are not predictively coded. This method periodically corrects errors regardless there has been an error or not. The method we propose is to insert frames that are not predictively coded directly after a packet has been lost, and only if a packet has been lost. Another area that is dealt with in this thesis is video sensor networks. These are small devices that have communication and computational capacity, they are equipped with an image sensor so that they can capture video. Since these devices in general have very limited resources in terms of energy, computation, communication and memory they demand a lot of the video compression algorithms used. In standard video compression algorithms the complexity is high for the encoder while the decoder has low complexity and is just passively controlled by the encoder. We propose video compression algorithms for wireless video sensor networks where complexity is reduced in the encoder by moving some of the image analysis to the decoder side. We have implemented our approach on actual low-power sensor nodes to test our developed algorithms. Finally we have built a "Digital Zoo" that is a complete system including a large scale outdoor video sensor network. The goal is to use the collected data from the video sensor network to create new experiences for physical visitors in the zoo, or "cyber" visitors from home. Here several topics that relate to practical deployments of sensor networks are addressed.
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| 4. |
- Kerdphon, Sutthichat, et al.
(författare)
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Diastereo- and Enantioselective Synthesis of Structurally Diverse Succinate, Butyrolactone, and Trifluoromethyl Derivatives by Iridium-Catalyzed Hydrogenation of Tetrasubstituted Olefins
- 2019
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 9:7, s. 6169-6176
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Tidskriftsartikel (refereegranskat)abstract
- A highly efficient iridium N,P-ligand-catalyzed asymmetric hydrogenation of functionalized tetrasubstituted olefins lacking a directing group has been developed. Various structural diverse chiral succinate derivatives were obtained in high yields and excellent enantio- and diastereoselectivities (up to 99% ee) using 0.5-1.0 mol % catalyst loadings. This stereoselective reaction is applicable for the synthesis of chiral acyclic molecules (up to >99% ee) having two contiguous stereogenic centers and is compatible with various aromatic, aliphatic, and heterocyclic systems, a variety of functional groups of different electronic nature. Furthermore, this asymmetric protocol allows a short enantioselective route to the butyrolactone building block, an intermediate in the synthesis of anticancer agent BMS-871 and pharmaceuticals (2S)-(-)-Verapamil and (2S)-(-)-Gallopamil.
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| 5. |
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| 6. |
- Kong, Wei-Jun, et al.
(författare)
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Iron-Catalyzed Cross-Coupling of α-Allenyl Esters with Grignard Reagents for the Synthesis of 1,3-Dienes
- 2023
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 25:1, s. 120-124
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Tidskriftsartikel (refereegranskat)abstract
- Structurally diverse 1,3-dienes are valuable building blocks in organic synthesis. Herein we report the iron-catalyzed coupling between α-allenyl esters and Grignard reagents, which provides a fast and practical approach to a variety of complex substituted 1,3-dienes. The reaction involves an inexpensive iron catalyst, mild reaction conditions, and provides easy scale up.
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| 7. |
- Krajangsri, Suppachai, 1955-, et al.
(författare)
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Chemoselective Iridium-catalysed Peterson olefination/Asymmetric Hydrogenation of beta-Hydroxy Silaned
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Herein we report the use of Ir-N,P catalysts for the asymmetric hydrogenation of β-hydroxy silanes via an in-situ generated olefin intermediate. The reaction proceeds via an acid catalysed Peterson olefination reaction and provides hydrogenated products in excellent ee’s of up to 99% accompanied with high isolated yields under mild reaction conditions and short reaction times. Modification of the reaction conditions provides a choice to hydrogenate either an olefin or a β-hydroxy silane in a chemo-selective manner leaving the other functionality unaffected in the product.
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| 8. |
- Krajangsri, Suppachai, et al.
(författare)
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Tandem Peterson olefination and chemoselective asymmetric hydrogenation of β-hydroxy silanes
- 2019
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Ingår i: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 10:12, s. 3649-3653
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Tidskriftsartikel (refereegranskat)abstract
- Here, we report the first Ir-N,P complex catalyzed tandem Peterson olefination and asymmetric hydrogenation of -hydroxy silanes. This reaction resulted in the formation of chiral alkanes in high isolated yields (up to 99%) and excellent enantioselectivity (up to 99% ee) under mild conditions. Modification of the reaction conditions provides a choice to transform either an olefin or the -hydroxy silane in a chemoselective manner. Additionally, based on this method, an expedient enantioselective synthesis of (S)-(+)--curcumene, from a simple ketone, was accomplished in two steps with 75% overall yield and 95% ee.
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| 9. |
- Li, Fei, et al.
(författare)
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Quantum Bacterial Foraging Optimization Algorithm
- 2014
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Ingår i: 2014 IEEE CONGRESS ON EVOLUTIONARY COMPUTATION (CEC). - : IEEE Press. - 9781479914883 ; , s. 1265-1272
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Konferensbidrag (refereegranskat)abstract
- This paper proposes a novel swarm intelligence optimization method which integrates bacterial foraging optimization (BFO) with quantum computing, called quantum bacterial foraging optimization (QBFO) algorithm. In QBFO, a multi-qubit which can represent a linear superposition of states in search space probabilistically is used to represent a bacterium, so that the quantum bacteria representation has a better characteristic of population diversity. A quantum rotation gate is designed to simulate the chemotactic step to drive the bacteria toward better solutions. Several tests are conducted based on benchmark functions including multi-peak function to evaluate optimization performance of the proposed algorithm. The numeric results show that the proposed QBFO has more powerful properties in convergence rate, stability and the ability of searching for the global optimal solution than the original BFO and quantum genetic algorithm. In addition, we applied our proposed QBFO to solve the traveling salesman problem, which is a well-known NP-hard problem in combinatorial optimization. The results indicate that the proposed QBFO shows better convergence behavior without premature convergence, and has more powerful properties in convergence rate, stability and the ability of searching for the global optimal solution, as compared to ant colony optimization algorithm and quantum genetic algorithm.
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| 10. |
- Lin, Feng, et al.
(författare)
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Functional studies of HLA and its role in SARS-CoV-2: Stimulating T cell response and vaccine development
- 2023
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Ingår i: Life Sciences. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0024-3205 .- 1879-0631. ; 315
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Forskningsöversikt (refereegranskat)abstract
- In the biological immune process, the major histocompatibility complex (MHC) plays an indispensable role in the expression of HLA molecules in the human body when viral infection activates the T-cell response to remove the virus. Since the first case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in 2019, how to address and prevent SARS-CoV-2 has become a common problem facing all mankind. The T-cell immune response activated by MHC peptides is a way to construct a defense line and reduce the transmission and harm of the virus. Presentation of SARS-CoV-2 antigen is associated with different types of HLA phenotypes, and different HLA phenotypes induce different immune responses. The prediction of SARS-CoV-2 mutation information and the design of vaccines based on HLAs can effectively activate autoimmunity and cope with virus mutations, which can provide some references for the prevention and treatment of SARS-CoV-2.
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| 11. |
- Liu, Jianguo, et al.
(författare)
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Regioselective Iridium-Catalyzed Asymmetric Monohydrogenation of 1,4-Dienes
- 2017
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 139:41, s. 14470-14475
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Tidskriftsartikel (refereegranskat)abstract
- A highly efficient regio- and enantioselective monohydrogenation of 1,4-dienes has been realized using an iridium catalyst with a chiral N,P-ligand under mild conditions. The substrate scope was studied and included both unfunctionalized as well as functionalized substituents on the meta- or para-position. Substrates having substituents with functionalities such as silyl protected alcohols or ketals were monohydrogenated in high regioselectivity and high enantiomeric excess (up to 98% ee).
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| 12. |
- Ponra, Sudipta, et al.
(författare)
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Asymmetric synthesis of 1,2-fluorohydrin : iridium catalyzed hydrogenation of fluorinated allylic alcohol
- 2020
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 11:41, s. 11189-11194
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a simple protocol for the preparation of 1,2-fluorohydrin by asymmetric hydrogenation of fluorinated allylic alcohols using an efficient azabicyclo thiazole-phosphine iridium complex. The iridium-catalyzed asymmetric synthesis of chiral 1,2-fluorohydrin molecules was carried out at ambient temperature with operational simplicity, and scalability. This method was compatible with various aromatic, aliphatic, and heterocyclic fluorinated compounds as well as a variety of polyfluorinated compounds, providing the corresponding products in excellent yields and enantioselectivities.
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| 13. |
- Ponra, Sudipta, et al.
(författare)
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Diastereo- and Enantioselective Synthesis of Fluorine Motifs with Two Contiguous Stereogenic Centers
- 2018
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 140:42, s. 13878-13883
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of chiral fluorine containing motifs, in particular, chiral fluorine molecules with two contiguous stereogenic centers, has attracted much interest in research due to the limited number of methods available for their preparation. Herein, we report an atom-economical and highly stereoselective synthesis of chiral fluorine molecules with two contiguous stereogenic centers via azabicyclo iridium-oxazoline-phosphine-catalyzed hydrogenation of readily available vinyl fluorides. Various aromatic, aliphatic, and heterocyclic systems with a variety of functional groups were found to be compatible with the reaction and provide the highly desirable product as single diastereomers with excellent enantioselectivities.
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| 14. |
- Qi, Di, et al.
(författare)
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Climate change drives rapid decadal acidification in the Arctic Ocean from 1994 to 2020
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 377:6614, s. 1544-1550
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Tidskriftsartikel (refereegranskat)abstract
- The Arctic Ocean has experienced rapid warming and sea ice loss in recent decades, becoming the first open-ocean basin to experience widespread aragonite undersaturation [saturation state of aragonite (Warag) < 1]. However, its trend toward long-term ocean acidification and the underlying mechanisms remain undocumented. Here, we report rapid acidification there, with rates three to four times higher than in other ocean basins, and attribute it to changing sea ice coverage on a decadal time scale. Sea ice melt exposes seawater to the atmosphere and promotes rapid uptake of atmospheric carbon dioxide, lowering its alkalinity and buffer capacity and thus leading to sharp declines in pH and Warag. We predict a further decrease in pH, particularly at higher latitudes where sea ice retreat is active, whereas Arctic warming may counteract decreases in Warag in the future.
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| 15. |
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| 16. |
- Wu, Haibo, et al.
(författare)
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Asymmetric Arene Hydrogenation with Cooperative Homogenous and Heterogeneous Rhodium Catalysis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Homogeneous and heterogeneous catalyzed reactions can seldom operate synergistically under the same conditions. Here we communicate the use of a single rhodium precursor that acts in both the homogeneous and heterogeneous phase for the asymmetric hydrogenation of simple substituted benzenes that, to date, constitute an unmet bottle-neck in the field. A simple asymmetric hydrogenation of a styrenic olefin, enabled by a ligand accelerated effect, accounted for the facial selectivity in the consecutive arene hydrogenation. Tuning the ratio between the phosphine ligand and the rhodium precursor controlled the formation of homogeneous and heterogeneous catalytic species that operates without interference from each other. The system is flexible in terms of both the chiral ligand and the nature of the external olefin. We anticipate that our findings will promote the development of asymmetric arene hydrogenations.
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| 17. |
- Wu, Haibo, 1989-, et al.
(författare)
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Asymmetric Full Saturation of Vinylarenes with Cooperative Homogeneous and Heterogeneous Rhodium Catalysis
- 2021
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 143:48, s. 20377-20383
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Tidskriftsartikel (refereegranskat)abstract
- Homogeneous and heterogeneous catalyzed reactions can seldom operate synergistically under the same conditions. Here we communicate the use of a single rhodium precursor that acts in both the homogeneous and heterogeneous phases for the asymmetric full saturation of vinylarenes that, to date, constitute an unmet bottleneck in the field. A simple asymmetric hydrogenation of a styrenic olefin, enabled by a ligand accelerated effect, accounted for the facial selectivity in the consecutive arene hydrogenation. Tuning the ratio between the phosphine ligand and the rhodium precursor controlled the formation of homogeneous and heterogeneous catalytic species that operate without interference from each other. The system is flexible in terms of both the chiral ligand and the nature of the external olefin. We anticipate that our findings will promote the development of asymmetric arene hydrogenations.
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| 18. |
- Wu, Haibo, 1989-
(författare)
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Controlling the Reactivity and Selectivity in Iridium- and Rhodium-Catalyzed Asymmetric Hydrogenation
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The work presented in this thesis is mainly focused on the development of iridium- or rhodium-catalyzed asymmetric hydrogenation featuring a number of practical concepts including cascade reaction, kinetic resolution, desymmetrization, and dearomatization. The protocols rely on gaining control of the reactivity among different olefins or olefin precursor as well as maintaining chemo- and stereo-selectivity in the hydrogenation. Furthermore, the application of the developed methodologies into the asymmetric synthesis of some bioactive natural products is also described.In the first part of this work (Chapter 2), we have developed a tandem Peterson olefination and asymmetric hydrogenation of β-hydroxy silanes that provides an efficient access to stereogenic carbons bearing benzyl-methyl substituents. This strategy is based upon the controllable chemoselectivity of hydrogenating either the β-hydroxy silane or an olefin in the same reaction system. A two-step asymmetric total synthesis of natural product (S)-(+)-Curcumene further illustrates the usefulness of this methodology.The second part of the thesis (Chapter 3) is focused on the development of two discriminative hydrogenations: kinetic resolution and desymmetrization. The developed methods exhibit excellent selectivity towards reaction of one enantiomer in a racemic mixture or a mono-hydrogenation of one enantiotopic group in a meso compound. A broad range of allylic alcohols or amides bearing one or two contiguous stereogenic centers could be obtained in high enantiomeric purity by using these discriminative hydrogenations. DFT calculations and kinetic modelling were applied to give insights into the origin of selectivity and the kinetics for the desymmetrization process. Based on the usefulness of these reactions, the third part of the thesis (Chapter 4) is focused on their applications into the asymmetric synthesis of key intermediates for the total synthesis of natural products including Pumiliotoxin A, Inthomycins (A and B), Zaragozic acid A and Invictolide.The last chapter (Chapter 5) describes the merging of homogenous and heterogeneous rhodium catalysis for the asymmetric hydrogenation of benzene derivatives, which is a long-standing challenge in the field. Based on the discovery that the commonly used rhodium precursors (such as [Rh(COD)]BF4) could undergo in situ formation of rhodium nanoparticles, we have expanded the application of well-established Rh/diphosphine catalytic system into efficient dearomative asymmetric hydrogenations.
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| 19. |
- Wu, Haibo, 1989-, et al.
(författare)
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Heterogeneous Copper-Catalyzed Cross-Coupling for Sustainable Synthesis of Chiral Allenes : Application to the Synthesis of Allenic Natural Products
- 2023
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 62:50
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Tidskriftsartikel (refereegranskat)abstract
- Classical Crabbé type SN2' substitutions of propargylic substrates has served as one of the standard methods for the synthesis of allenes. However, the stereospecific version of this transformation often requires either stoichiometric amounts of organocopper reagents or special functional groups on the substrates, and the chirality transfer efficiency is also capricious. Herein, we report a sustainable methodology for the synthesis of diverse 1,3-di and tri-substituted allenes by using a simple and cheap cellulose supported heterogeneous nanocopper catalyst (MCC-Amp-Cu(I/II)). This approach represents the first example of heterogeneous catalysis for the synthesis of chiral allenes. High yields and excellent enantiospecificity (up to 97 % yield, 99 % ee) were achieved for a wide range of di- and tri-substituted allenes bearing various functional groups. It is worth noting that the applied heterogeneous catalyst could be recycled at least 5 times without any reduced reactivity. To demonstrate the synthetic utility of the developed protocol, we have applied it to the total synthesis of several chiral allenic natural products.
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| 20. |
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| 21. |
- Wu, Haibo, et al.
(författare)
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Kinetic resolution of racemic allylic alcohols via iridium-catalyzed asymmetric hydrogenation : scope, synthetic applications and insight into the origin of selectivity
- 2021
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Ingår i: Chemical Science. - : Royal Society of Chemistry (RSC). - 2041-6520 .- 2041-6539. ; 12:5, s. 1937-1943
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Tidskriftsartikel (refereegranskat)abstract
- Asymmetric hydrogenation is one of the most commonly used tools in organic synthesis, whereas, kinetic resolution via asymmetric hydrogenation is less developed. Herein, we describe the first iridium catalyzed kinetic resolution of a wide range of trisubstituted secondary and tertiary allylic alcohols. Large selectivity factors were observed in most cases (s up to 211), providing the unreacted starting materials in good yield with high levels of enantiopurity (ee up to >99%). The utility of this method is highlighted in the enantioselective formal synthesis of some bioactive natural products including pumiliotoxin A, inthomycin A and B. DFT studies and a selectivity model concerning the origin of selectivity are presented.
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| 22. |
- Wu, Haibo, et al.
(författare)
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Site- and Enantioselective Iridium-Catalyzed Desymmetric Mono-Hydrogenation of 1,4-Dienes
- 2021
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 60:35, s. 19428-19434
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Tidskriftsartikel (refereegranskat)abstract
- The control of site selectivity in asymmetric mono-hydrogenation of dienes or polyenes remains largely underdeveloped. Herein, we present a highly efficient desymmetrization of 1,4-dienes via iridium-catalyzed site- and enantioselective hydrogenation. This methodology demonstrates the first iridium-catalyzed hydrogenative desymmetriation of meso dienes and provides a concise approach to the installation of two vicinal stereogenic centers adjacent to an alkene. High isolated yields (up to 96%) and excellent diastereo- and enantioselectivities (up to 99:1 d.r. and 99% ee) were obtained for a series of divinyl carbinol and divinyl carbinamide substrates. DFT calculations reveal that an interaction between the hydroxy oxygen and the reacting hydride is responsible for the stereoselectivity of the desymmetrization of the divinyl carbinol. Based on the calculated energy profiles, a model that simulates product distribution over time was applied to show an intuitive kinetics of this process. The usefulness of the methodology was demonstrated by the synthesis of the key intermediates of natural products zaragozic acid A and (+)-invictolide.
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| 23. |
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| 24. |
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| 25. |
- Xiong, Yan, et al.
(författare)
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Small molecule Z363 co-regulates TAF10 and MYC via the E3 ligase TRIP12 to suppress tumour growth
- 2023
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Ingår i: CLINICAL AND TRANSLATIONAL MEDICINE. - : JOHN WILEY & SONS LTD. - 2001-1326. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe MYC oncoprotein, also known as the master regulator of genes, is a transcription factor that regulates numerous physiological processes, including cell cycle control, apoptosis, protein synthesis and cell adhesion, among others. MYC is overexpressed in approximately 70% of human cancers. Given its pervasive role in cancer biology, MYC down-regulation has become an attractive cancer treatment strategy. MethodsThe CRISPR/Cas9 method was used to produce KO cell models. Western blot was used to analyzed the expressions of MYC and TATA-binding proteinassociated factors 10 (TAF10) in cancer cells (MCF7, A549, HepG2 cells) Cell culture studies were performed to determine the mechanisms by which small molecules (Z363119456, Z363) affects MYC and TAF10 expressions and functions. Mouse studies were carried out to investigate the impact of Z363 regulation on tumor growth. ResultsZ363 activate Thyroid hormone Receptor-interacting Protein 12 (TRIP12), which phosphorylates MYC at Thr58, resulting in MYC ubiquitination and degradation and thereby regulating MYC target genes. Importantly, TRIP12 also induces TAF10 degradation, which reduces MYC protein levels. TRIP12, an E3 ligase, controls MYC levels both directly and indirectly by inhibiting MYC or TAF10 activity. ConclusionsIn summary,these results demonstrate the anti-cancer properties of Z363, a small molecule that is co-regulated by TAF10 and MYC.
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| 26. |
- Yang, Bin, 1987-, et al.
(författare)
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Total Synthesis of Strigolactones via Palladium-Catalyzed Cascade Carbonylative Carbocyclization of Enallenes
- 2024
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Ingår i: Organic Letters. - 1523-7060 .- 1523-7052. ; 26:22, s. 4637-4642
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Tidskriftsartikel (refereegranskat)abstract
- Here we report an efficient route for synthesizing strigolactones (SLs) and their derivatives. Our method relies on a palladium-catalyzed oxidative carbonylation/carbocyclization/carbonylation/alkoxylation cascade reaction, which involves the formation of three new C–C bonds and a new C–O bond while cleaving one C(sp3)–H bond in a single step. With our versatile synthetic strategy, both naturally occurring and artificial SLs were prepared.
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| 27. |
- Yang, Haibo, et al.
(författare)
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Coupling Downscaling and Calibrating Methods for Generating High-Quality Precipitation Data with Multisource Satellite Data in the Yellow River Basin
- 2024
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Ingår i: Remote Sensing. - 2072-4292. ; 16:8
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Tidskriftsartikel (refereegranskat)abstract
- Remote sensing precipitation data have the characteristics of wide coverage and revealing spatiotemporal information, but their spatial resolution is low. The accuracy of the data is obviously different in different study areas and hydrometeorological conditions. This study evaluated four precipitation products in the Yellow River basin from 2001 to 2019, constructed the optimal combined product, conducted downscaling with various machine algorithms, and performed corrections using meteorological station precipitation data to analyze the spatiotemporal trends of precipitation. The results showed that (1) GPM and MSWEP had the best four evaluation indicators, with R2 values of 0.93 and 0.90, respectively, and the smallest FSE and RMSE, with a BIAS close to 0. A high-precision mixed precipitation dataset, GPM-MSWEP, was constructed. (2) Among the three methods, the downscaling results of DFNN showed higher accuracy. (3) The results, after correction with GWR, could more effectively enhance the accuracy of the data. (4) Precipitation in the Yellow River Basin showed a decreasing trend in January, September, and December, while it exhibited an increasing trend in other months and seasons, with 2002 and 2016 being points of abrupt change. This study provides a reference for the production of high-precision satellite precipitation products in the Yellow River basin.
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| 28. |
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| 29. |
- Zhu, Haibo, et al.
(författare)
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Insight into Benzothiadiazole Acceptor in D-A-pi-A Configuration on Photovoltaic Performances of Dye-Sensitized Solar Cells
- 2014
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 2:4, s. 1026-1034
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Tidskriftsartikel (refereegranskat)abstract
- The option of conjugated pi-linkers is critical for molecular engineering toward the energy-level strategy of donor-pi-acceptor (D-pi-A) sensitizers. There is always a balance in the optimization of a it-linker. The pi-conjugation should be enlarged to expand the light-harvesting capability of sensitizers for an increase in photocurrent; however, the oversized it-linker also would affect seriously the photovoltage and photostability. Two sensitizers, WS-22 and WS-23, are constructed without or with benzothiadiazole (BTD) in a molecular skeleton, aiming to gain insight into the effect of an auxiliary acceptor in D-A-pi-A sensitizers on the photophysical and photovoltaic performances, especially focusing on the exploitation of the short circuit current density (J(sc)) and open circuit voltage (V-oc). Compared with the typical D-pi-A sensitizer WS-22, the incorporation of an auxiliary acceptor of BTD in WS-23 can improve the light-harvesting ability both in red-shifting the absorption peaks and the increment of absorption coefficient. The predominant increase by 15.6% in light-harvesting efficiency (LHE) of WS-23 results in a relatively higher J(sc) from 13.77 (WS-22) to 16.91 mA cm(-2) (WS-23). Moreover, the improvement of the V-oc in WS-23 is originated by a synergy contribution of the uplifting of E-CB and inhibition of charge recombination. The stepped light-induced transient (SLIT) measurements indicate that the introduction of BTD can negatively shift the conduction band of the TiO2 film. For WS-23, the higher molecular dipole moment can bring forth a more effective charge separation between donor and acceptor units, also resulting in an increase in V-oc. The incorporated BTD unit can increase V-oc by 57 mV, arising from the CB edge shift of TiO2 (accounting for 40%, 23 mV) and the retarding charge recombination (accounting for 60%, 34 mV). As a consequence, WS-23 realizes an optimizing photovoltaic efficiency (eta = 8.15%), with an improvement of 36.5% with respect to WS-22.
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