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Role of calcimicrobes and microbial carbonates in the Late Carboniferous(Moscovian) mounds in southern Guizhou,South China

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Journal of Palaeogeography 2019年第4期8卷 346-359页

作者： Wen-Tao Huang Yong-Li Zhang Chang-Qing Guan Zhuo-Wei Miao Xiao-Hong Chen Zhen-Yuan Yang Xiao Li en-pu gong College of Resources and Civil engineering Northeastern UniversityShenyang 110819Liaoning ProvineeChina College of Resources and Materials Northeastern University at QinhuangdaoQinhuangdao 066004Hebei ProvineeChina

Various microbial fabrics characterize late Moscovian mounds in Houchang Town,southern Guizhou,South *** dominant components of the mounds are microbial boundstones with stromatolitic structures,irregular oncoid-like forms,and wrinkle *** recognized in the mounds include Girvanella,Ortonella,Wetheredella-like,Palaeomicrocodium-like,and some problematic calcimicrobes occurring in deposits between microbial boundstones,in thrombolitic textures,and in some *** carbonates are common in the substrate and interior of the mounds,including thrombolitic textures,microstromatolites,microbial ooids,oncoids,irregular encrusted layers,microbial mat debris,and microbial *** and microbial carbonates played an important role in the construction of the mounds:Girvanella might have contributed as a source of lime mud that formed the mound and stabilized the coral frame;thrombolitic mats could trap and fix sediments and bioclasts,contributing to the stabilization of substrate and mound limestones;and,microbial boundstone,clotted micrite and micritized bioclast could provide a hard substrate for encrusting metazoans(e.g.,bryozoans,Ivanovia).The abundant microbial fabrics in the mounds indicate that microbial activity was widespread in Moscovian reef mounds in southern Guizhou,and this suggests that microbial organisms were the primary mound builders in the study area.

关键词： Microfossils Microbial carbonates Mounds Late Carboniferous Moscovian Guizhou

Chiral phosphoramidite ligand-modulated palladium auto-tandem catalysis for asymmetric dehydrogenative dienylation of imines with α-alkenes

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Science China Chemistry 2025年

作者： Zhong-Sheng Nong Hao-Fan Qian Ying-Chun Chen pu-Sheng Wang Liu-Zhu gong Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of China Key Laboratory of Drug Targeting and Drug Delivery System (Sichuan University) Ministry of Education and Sichuan Research Center for Drug Precision Industrial Technology West China School of Pharmacy Sichuan University School of Materials and Chemistry Southwest University of Science and Technology

The development of efficient processes allowing rapid access to complex chiral molecules from easily available alkenes is a long-term pursuit in the synthetic chemistry community. Transition metal-catalyzed asymmetric functionalization of allylic C–H bond represents a unique alternative toward this goal. However, enantioselective dehydrogenative transformation of olefins to value-added optically enriched molecules remains yet to be discovered. Here, we report a highly enantioselective dehydrogenative dienylation of imines with unactivated α-alkenes driven by the synergistic action of palladium complex and carboxylic acid. Chiral phosphoramidite ligands turned out to be superior in modulating the performance of palladium autotandem catalysis and allowed a broad range of α-alkenes and imines to be transformed into chiral dienylamines. Mechanistic studies suggest that the dienes could be in situ generated from α-alkenes through a palladium(0)-mediated dehydrogenative process in the presence of excess benzoquinone oxidants, and then participated in the Pd-chiral phosphoramidite-catalyzed intermolecular vinylogous-type addition to the imines activated by the carboxylic acid co-catalyst. Notably, the second β-H elimination occurring in the dienylation event might be the turnover-limiting step.

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Precipitated phases of superaustenitic stainless steel 654SMO

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Journal of Iron and Steel Research International 2017年第7期24卷 743-749页

作者： Zhi-gang Song en-xiang pu Special Steel Institute Central Iron & Steel Research Institute School of Materials Science and engineering Tsinghua University

The phase diagram of superaustenitic stainless steel 654SMO was calculated by thermodynamic software and the precipitated phases in the specimens aged at 800-1100°C for 1hwere studied by methods of physicochemical phase analysis,scanning electron microscopy and transmission electron *** results showed that the size of precipitated particles increased with increasing the *** amount of second phases reached the maximum value at 900°C,but decreased above 900°*** were about eight kinds of precipitated phases in 654SMO includingσphase,Cr_2N,μphase,χphase,Laves phase,M_（23）C_6,M_6C and M_3C,in which theσphase and Cr_2N were the dominant precipitated phases.

关键词： 654SMO Precipitation Superaustenitic stainless steel Precipitated phase Second phase

Characteristics of two transferable aminoglycoside resistance plasmids in Escherichia coli isolated from pig and chicken manure

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Frontiers of environmental Science & engineering 2019年第3期13卷 99-113页

作者： Chengjun pu Xiaoyan gong Ying Sun Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation College of Resources and Environmental Sciences China Agricultural University Beijing 100193 China

Plasmid-mediated antibiotic resistance genes (ARGs) have recently become a more prominent concern in the global environment. However, the prevalence of aminoglycoside resistance plasmids in the livestock industry is under reported. In this study, two transferable aminoglycoside resistance plasmids, pRKZ3 and pKANJ7, isolated from pig and chicken manure, were characterized. Results showed that pRKZ3 (8236 bp) is a non-conjugative IncQ plasmid and contains genes encoding for plasmid replication and stabilization (repA, repB and repC), mobilization (mob), and antibiotic resistance (arr-3 and aacA). pKANJ7 (30142 bp) is a conjugative IncX plasmid which codes for a type IV secretion system (T4SS). Conjugative transfer experiments showed that the optimal mating time of pKANJ7 was 8 h under the starvation condition, but the number of tranconjugants increased with time under the nutrient condition. Statistical analysis indicated that the two plasmids had little impact on the growth of their hosts, but a relatively high level of fitness cost due to pKANJ7 was observed. We also found that the fitness cost of plasmids depended on their hosts. Compared with pKANJ7, the relative fitness cost index of pRKZ3 varied within a narrow range during the 10 days of competition. The low level of fitness cost of pRKZ3 might contribute to the persistence of the plasmid in the environment. Our study provides new information for understanding the characterizations of antibiotic resistance plasmids (ARPs) in manure sources and helps to clarify the transfer and persistence of ARPs in the environment following the application of manure.

关键词： Escherichia coli Characteristics Aminoglycoside resistance plasmids Transfer Persistence

Study on the performance of the A*Prune QoS routing algorithm for intelligent optical networks and its improvements

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The Journal of China Universities of Posts and Telecommunications 2006年第3期13卷 65-70页

作者： SUN Quan WANG gong-pu School of Telecommunication engineering Beijing University of Posts and Telecommunications Beijing 100876 China School of Network Education Beijing University of Pos'ts and TelecommunicationsBeijing 100088 China

The A＇Prune quality of service （QoS） routing algorithm was proposed to compute K-shortest paths satisfying multiple QoS constraints, The A＇Prune is considered to be one of the practical routing algorithms for intelligent optical networks because of its flexibility in handling many practical constraints, This article gives detailed performance studies of the algorithm through extensive simulation experiments. We found that both the running time and the memory space requirements of the algorithm are large, especially when the network size increases, in this article, we also propose an approach to improving the performance of the A＇Prune algorithm. The improvements should make the A＇Prune algorithm more attractive for practical use in intelligent optical networks.

关键词： constrained paths K-shortest paths QoS routing,intelligent optical networks

Pd-Catalyzed Asymmetric Allylic C—H Functionalization

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Chinese Journal of Chemistry 2023年第15期41卷 1841-1848页

作者： pu-Sheng Wang Liu-Zhu gong Department of Chemistry University of Science and Technology of ChinaHefeiAnhui 230026China Center for Excellence in Molecular Synthesis of CAS University of Science and Technology of ChinaHefeiAnhui 230026China

Comprehensive Summary Pd-catalyzed asymmetric allylic C—H functionalization has emerged as a powerful tool to access chiral,densely functionalized molecules from easily accessible alkenes,enabling the increase of the step-or atom-economy by minimizing functional group manipulations for preparing allylating *** to the inadequacy of stereoselection strategies,the asymmetric allylic C—H functionalization is still in the early *** this essay,we will describe our journey to identification of asymmetric catalytic systems,mechanism of allylic C—H activation,control of stereo-and regioselectivity,and applications in asymmetric synthesis.

关键词： C-H activation Asymmetric catalysis Allylation Palladium Allylic compounds Regioselectivity Alkenes

REFLECTION AND TRANSMISSION OF OBLIQUELY INCIDenT RAYLEIGH SURFACE WAVES BY A VISCOELASTIC INTERPHASE

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Acta Mechanica Solida Sinica 1998年第3期11卷 229-240页

作者： Li Zailiang gong pu Beijing Univ Aeronaut & Astronaut Inst Solid Mech Beijing 100083 Peoples R China Huazhong Univ Sci & Technol Dept Mech Wuhan 430074 Peoples R China

The reflection and transmission of obliquely incident Rayleighsurface waves by an in- terphase between two quarter spaces ofidentical or different materials, have been investigated. Themechanical behavior of the interphase is represented by a thinviscoelastic layer. By using the full space Green's functions due toa spatially harmonic line load, the mathematical statement of the3-dimen- sion problem is reduced to a 2-dimension system of singularintegral equations. The far-field behavior of the scattered wavesleads to the definition of reflection and transmission coefficients,R and T.

关键词： Rayleigh surface waves interphase reflection and transmissioncoefficients

Nonlinear optics in the electron-hole continuum in 2D semiconductors:two-photon transition, second harmonic generation and valley current injection

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Science Bulletin 2019年第15期64卷 1036-1043页

作者： pu gong Hongyi Yu Yong Wang Wang Yao Department of Physics and Center of Theoretical and Computational Physics The University of Hong KongHong KongChina School of Physics Nankai UniversityTianjin 300350China

We investigate two-photon transitions to the electron-hole scattering continuum in monolayer transition-metal dichalcogenides, and identify two contributions to this nonlinear optical process with opposite circularly polarized valley selection rules. In the non-interacting limit, the competition between the two contributions leads to a crossover of the selection rule with the increase of the two-photon energy. With the strong Coulomb interaction between the electron and hole, the two contributions excite electron-hole scattering states in orthogonal angular momentum channels, while the strength of the transition can be substantially enhanced by the interaction. Based on this picture of the two-photon transition, the second harmonic generation(SHG) in the electron-hole continuum is analyzed, where the Coulomb interaction is shown to greatly alter the relative strength of different cross-circular polarized SHG processes. Valley current injection by the quantum interference of one-photon and two-photon transition is also investigated in the presence of the strong Coulomb interaction, which significantly enhances the injection rate.

关键词： 2D semiconductors Nonlinear optics Electron-hole continuum Two-photon transition Second-harmonic generation Valley current injection

Palladium-catalyzed asymmetric allylic C–H alkylation of 1,4-dienes and glycine Schiff bases

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Science China Chemistry 2020年第4期63卷 454-459页

作者： Tian-Ci Wang pu-Sheng Wang Liu-Zhu gong Hefei National Laboratory for Physical Sciences at the Microscale and Department of Chemistry University of Science and Technology of ChinaHefei 230026China Center for Excellence in Molecular Synthesis of Chinese Academy of Sciences Hefei 230026China

A highly regio-and enantioselective allylic C–H alkylation of 1,4-dienes with glycine Schiff bases has been established by chiral palladium-phosphoramidite catalysis. This reaction can proceed under mild conditions and tolerate a wide scope of 1,4-dienes,delivering structurally diverse chiral β-branched α-amino acid surrogates in moderate to high yields and with high levels of regio-, Z/E-, diastereo-and enantioselectivities.

关键词： asymmetric catalysis palladium allylic C–H alkylation 1,4-diene glycine Schiff base