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Combinations of electron and proton donors in transition-metal complex mediated nitrogen reduction reactions

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Science China Chemistry 2024年第7期67卷 2136-2154页

作者： Delong Han Li Yang hao Huang Priyanka Chakraborty Shashikant u.Dighe Kuo-Wei Huang KAuST Catalysis Center and Division of Physical Science and Engineering King Abdullah University of Science and TechnologyThuwal 23955Saudi Arabia Agency for Science Technologyand ResearchInstitute of Materials Research and Engineering and Institute of Sustainability for ChemicalsEnergy and EnvironmentSingapore 138634Singapore

Nitrogen fixation is a complex process involving the transfer of six electrons and *** from the conventional Haber-Bosch process,which relies on hydrogen(H_(2))to provide both electrons and protons to reduce nitrogen(N_(2)),homogeneous transition metal complex-catalyzed N_(2)reduction reactions(NRR)employ an array of electron and proton donors or even electron donors combined with *** the synthesis of diverse catalytic progress,the categories of donors have seen rapid ***,existing literature only provides summaries regarding the metal,ligands,and *** the significance of electron and proton donor combinations in nitrogen reduction reactions,no literature has thoroughly reviewed this ***,we hereby compiled a comprehensive list of commonly used reagents in N_(2)reduction and classified them according to their specific donor *** review presents clear and organized information about these combinations,along with a summary of their general performance trend in NRR with related ***,we conclude the discussion by highlighting key points for researchers to consider when selecting catalysts and donor combinations,with the ultimate goal of advancing the field of nitrogen fixation.

关键词： dinitrogen reduction reaction reducing donor combination transition metal complexes homogeneous catalysis

A newly unraveled 13.6-year oscillation from GPS displacements and its potential implications for the dynamic reference frame

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Science China Earth Sciences 2024年第10期67卷 3204-3212页

作者： hao DING Weiping JIANG School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan UniversityWuhan 430079China GNSS Research Center Wuhan UniversityWuhan 430079China

Numerous practical geodetic and geophysical applications necessitate precise measurements of GNSS displacements at the millimeter or sub-millimeter level. To attain such precision, it is imperative to identify and analyze the unidentified decadal signals inherent in the GPS displacements. In this research, we employ the optimal sequence estimation method to effectively detect an about 13.6-year oscillational signal with an excited amplitude of 3.6±1.2 mm in the u-components of the GPS displacements. It is noteworthy that this signal demonstrates a consistent spatial pattern characterized by the spherical harmonic Y_(2,-2). We conduct a comparative analysis with the 13.6-year oscillation observed in length-of-day variations(and geomagnetic records), finding that they are in reverse phase. After eliminating the Earth's external excitation sources through the utilization of two distinct in-situ hydrological records, we suggest that the 13.6-year GPS signal may come from the internal motions within the Earth. However, the specific excitation source and the detailed physical mechanism remain uncertain. Additionally, we develop a mathematical displacement model to explain the 13.6-year signal. Our findings indicate that this signal can result in displacements of up to 1.37 mm and velocity effects of 0.63 mm/yr(for u-component) at maximum. These results underscore the necessity of incorporating this 13.6-year signal into the construction and maintenance of a dynamic reference frame at the millimeter level.

关键词： GPS displacements Decadal changes 13.6-year oscillation Displacement model Dynamic reference frame

Very long wave infrared quantum dot photodetector up to 18μm

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Light(Science & Applications) 2024年第4期13卷 772-782页

作者： Xiaomeng Xue Qun hao Menglu Chen School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China. Westlake Institute for Optoelectronics FuyangHangzhou 311421China. Physics Department Changchun University of Science and TechnologyChangchun 130022China

Colloidal quantum dots(CQDs)are of interest for optoelectronic devices because of the possibility of high-throughput solution processing and the wide energy gap tunability from ultraviolet to infrared *** may question about the upper limit on the CQD wavelength *** date,although the CQD absorption already reaches terahertz,the practical photodetection wavelength is limited within mid-wave *** figure out challenges on CQD photoresponse in longer wavelength,would reveal the ultimate property on these ***’s more,it motivates interest in bottom-up infrared photodetection with less than 10%cost compared with epitaxial growth semiconductor *** this work,developing a re-growth method and ionic doping modification,we demonstrate photodetection up to 18μm wavelength on HgTe *** liquid nitrogen temperature,the responsivity reaches 0.3 A/W and 0.13 A/W,with specific detectivity 6.6×108 Jones and 2.3×109 Jones for 18μm and 10μm CQD photoconductors,*** work is a step toward answering the general question on the CQD photodetection wavelength limitation.

关键词： quantum wave ultraviolet

A novel distributed solar refrigeration system based on evacuated u-tube solar collector and elastocaloric refrigerator

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Science China(Technological Sciences) 2024年第9期67卷 2797-2810页

作者： LI hao ZHANG HouCheng College of New Energy Ningbo University of TechnologyNingbo 315211China

Refrigeration challenges in regions with electricity shortages significantly decrease the quality of life for residents. In response to the prevalent refrigeration challenges in power-deficient areas, a novel distributed solar refrigeration system, comprising an evacuated u-tube solar collector and elastocaloric refrigerator, is theoretically introduced. Theoretical formulations for the energy efficiency and cooling power of the solar refrigeration system are presented to facilitate predictive assessments of the performance properties. under typical conditions, the energy efficiency and cooling power of the solar refrigeration system are,respectively, 4.84% and 200.15 W. Subsequently, an extensive parameter study is conducted to comprehensively uncover key performance influencers and identify avenues for improvement. In addition, local sensitivity analyses identify that the length ratio is the top influential parameter, while the heat transfer fluid flow rate is the least sensitivity. A pragmatic case study,conducted with the weather data of Ningbo City, China, serves to empirically predict the performance of the hybrid system within the constraints of practical circumstances.

关键词： evacuated u-tube solar collector elastocaloric refrigerator solar refrigeration solar energy thermal utilization system integration

Toxicity mechanisms of photodegraded polyvinyl chloride nanoplastics on pea seedlings

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Frontiers of Environmental Science & Engineering 2024年第4期18卷 111-124页

作者： hao Wu Beibei He Bocheng Chen An Liu College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Nanoplasctics(NPs),which are very small in particle size,exert toxic effect to ***,compared to original NPs,photodegraded NPs would pose higher *** is because their relatively higher specific surface areas and the presence of additives which can more easily *** original NPs and aged NPs affect plant growth has not been widely *** work chose polyvinyl chloride NPs(PVC-NPs)that were subjected to up to 1000 h uV light radiation to explore the impact of PVC-NPs on the growth of pea seedlings(Pisum Sativum L.).The results indicated the existence of PVC-NPs with longer uV light radiation time and higher concentrations had more negative influences on pea seedlings’growth such as germination rate(decreased by 10.6%–22.5%),stem length(decreased by 2.8%–8.1%),dry weight(decreased by 6.3%–7.1%)and fresh weight(decreased by 6.7%–14.8%).It was also noted that photodegraded PVC-NPs resulted in damage to leaf stomata and roots,hindering photosynthesis and absorption of nutrients and hence the decrease in chlorophyll and soluble sugar *** to transcriptomic investigation results,the presence of aged PVC-NPs primarily influenced protein processing in endoplasmic reticulum(upregulated metabolic pathway)and phenylpropanoid biosynthesis(downregulated metabolic pathway)of pea *** results provide an in-depth understanding of how NPs influence the growth of plants.

关键词： Nanoplasctics Polyvinyl chloride Toxicity mechanisms Plant growth

A Degree Condition for Graphs Having All(a,b)-parity Factors

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 656-664页

作者： hao-dong LIu Hong-liang Lu School of Mathematics and Statistics Xi'an Jiaotong UniversityXi'an 710049China

Let a and b be positive integers such that a≤b and a≡b(mod 2).We say that G has all(a,b)-parity factors if G has an h-factor for every function h:V(G)→{a,a+2,…,b-2,b} with b|V(G)| even and h(v)≡b(mod 2) for all v∈V(G).In this paper,we prove that every graph G with n≥2(b+1)(a+b) vertices has all(a,b)-parity factors if δ(G)≥(b^(2)-b)/a,and for any two nonadjacent vertices u,v ∈V(G),max{d_(G)(u),d_(G)(v)}≥bn/a+***,we show that this result is best possible in some sense.

关键词： degree condition all(a,b)-factors

Detection of a reassortant swine H1N2 influenza A virus from pigs in Hong Kong

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Virologica Sinica 2024年第2期39卷 343-346页

作者： Guoqian Gu Congnuan Liu Song hao Lee Lewis Sze Chun Choi Michael T.Wilson Dirk u.Pfeiffer Yun Young Go Department of Infectious Diseases and Public Health Jockey Club College of Veterinary Medicine and Life SciencesCity University of Hong KongHong Kong SARChina Center for Applied One Health Research and Policy Advice Jockey Club College of Veterinary Medicine and Life SciencesCity University of Hong KongHong Kong SARChina College of Veterinary Medicine Konkuk UniversitySeoul143-701Republic of Korea

Dear Editor,Influenza A viruses(IAVs)are responsible for significant respiratory illnesses in humans and a broad range of animal *** outbreaks and the rapid spread of genetically and antigenically distinct IAVs represent a considerable challenge for swine *** are susceptible to avian and human IAV infections and are considered“mixing vessels”where human,avian,and swine IAVs can recombine and generate novel reassortant influenza viruses with pandemic potential(Vincent et al.,2014).

关键词： swine influenza mixing

First-principles calculation on the electronic structures, phonon dynamics, and electrical conductivities of Pb_(10)(PO_(4))_(6O) and Pb_(9)Cu(PO_(4))_(6O) compounds

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Journal of Materials Science & Technology 2024年第6期173卷 218-224页

作者： L.Y.hao E.G.Fu State Key Laboratory of Nuclear Physics and Technology Department of Technical PhysicsSchool of PhysicsPeking UniversityBeijing 100871China

Superconducting materials with high critical temperature have the potential to revolutionize many fields,including military,electronic communications,and power ***,scientists around the world have been tirelessly working with the ultimate goal of achieving high-temperature *** 2023,a preprint by Lee et *** South Korea claimed the discovery of ultra-high-temperature superconductivity with a critical temperature of up to 423 K in Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037),which caused a worldwide sensation and ***,the electronic structures,phonon dynamics,and electrical conductivities of LK-99 and its parent compound lead-apatite have been calculated using first-principles *** results show that the lead-apatite compound and the LK-99 compound are insulator and half-metal *** flat band characteristic is consistent with previous *** electrical conductivity of the LK-99 compound shows two extreme points,and the electrical conductivity along the C-axis increases significantly after 400 *** phonon dispersion spectra of the compounds were investigated,demonstrating their dynamic instability.

关键词： Superconductivity LK-99 Lead-apatite First-principles calculation

MLDA:a multi-level k-degree anonymity scheme on directed social network graphs

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Frontiers of Computer Science 2024年第2期18卷 199-215页

作者： Yuanjing hao Long LI Liang CHANG Tianlong Gu Guangxi Key Laboratory of Trusted Software Guilin University of Electronic TechnologyGuilin 541004China Engineering Research Center of Trustworthy AI(Ministry of Education) Jinan UniversityGuangzhou 510632China

With the emergence of network-centric data,social network graph publishing is conducive to data analysts to mine the value of social networks,analyze the social behavior of individuals or groups,implement personalized recommendations,and so ***,published social network graphs are often subject to re-identification attacks from adversaries,which results in the leakage of users’***-anonymity technology is widely used in the field of graph publishing,which is quite effective to resist re-identification ***,the current researches still exist some issues to be solved:the protection of directed graphs is less concerned than that of undirected graphs;the protection of graph structure is often ignored while achieving the protection of nodes’identities;the same protection is performed for different users,which doesn’t meet the different privacy requirements of ***,to address the above issues,a multi-level-degree anonymity(MLDA)scheme on directed social network graphs is proposed in this ***,node sets with different importance are divided by the firefly algorithm and constrained connectedness upper approximation,and they are performed different-degree anonymity protection to meet the different privacy requirements of ***,a new graph anonymity method is proposed,which achieves the addition and removal of edges with the help of fake *** addition,to improve the utility of the anonymized graph,a new edge cost criterion is proposed,which is used to select the most appropriate edge to be ***,to protect the community structure of the original graph as much as possible,fake nodes contained in a same community are merged prior to fake nodes contained in different *** results on real datasets show that the newly proposed MLDA scheme is effective to balance the privacy and utility of the anonymized graph.

关键词： directed social network graph graph publishing k-degree anonymity community structure graph utility