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Catalytically generated noncovalent ammonium dienolate:a versatile platform for the development of organocatalytic asymmetric cascade reactions

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Science China Chemistry 2024年第8期67卷 2524-2546页

作者： Jun-Bing Lin Dong-sheng Ji peng-Fei Xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China Shaanxi Key Laboratory of Chemical Reaction Engineering College of Chemistry and Chemical EngineeringYan’an UniversityYan’an 716000China

Organocatalytic cascade reactions represent a powerful strategy for the rapid construction of complex chiral molecules with multiple stereocenters from simple substrates under mild conditions. The intriguing structural feature and diverse reactivity of catalytically generated dienolate species render them competent and versatile intermediates for the development of practical and valuable cascade reactions. Over the past years, a plethora of innovative and pioneering noncovalent ammonium dienolatemediated cascade reactions have been designed and implemented under the catalysis of chiral organocatalysts, making dienolate activation a general, robust, and complementary method for the functionalization of unsaturated carbonyl compounds and related substances. This review illustrates the recent advances in organocatalytic noncovalent ammonium dienolate-mediated cascade reactions(mainly from 2010 to 2023), including the cascade transformations of ammonium dienolates directly generated from unsaturated ketone/aldehyde, ester/lactone/azlactone, amide/lactam/pyrazolone/oxindole, and alkylidene nitrile compounds. The contents are arranged based on the reaction types of the ammonium dienolates, with an emphasis on cascade 2,5-, 3,5-, and 4,5-difunctionalizations of these intermediates. Furthermore, other cascade reactions involving the 1,3-, 2,3-, and even more complex 3,4,5-reactivities of ammonium dienolates were also discussed. The reaction pathway, reaction stereoinduction, and synthetic applications of the ammonium dienolate-mediated cascade reactions were highlighted throughout the article. As a stimulating and ever-growing research area, the organocatalytic noncovalent ammonium dienolate-mediated cascade reactions are expected to continue demonstrating their magic power for constructing chiral targets in the future and further expanding the boundaries of asymmetric catalysis.

关键词： organocatalysis asymmetric catalysis ammonium dienolate cascade reaction difunctionalization

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The First Total Synthesis of 16-Hydroxygeranylgeraniol

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Chinese Chemical Letters 2003年第3期14卷 249-250页

作者： Li Zeng peng Tian sheng MEI 等 NationalLaboratoryofAppliedOrganicChemistry InstituteofOrganicChemistryLanzhouUniversityLanzhou730000 NationalLaboratoryofAppliedOrganicChemistry InstituteofOrganicChemistryLanzh

Facile synthesis of 16-hydroxygeranylgeranio 1, a naturally occurring alicyclic diterpene, by alkylation reaction of allylic iodide 3 with phenyl sulfone 4, is described.

关键词： Total synthesis 16-hydroxygeranylgeraniol diterpene.

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Modeling of flow and debris ejection in blasting erosion arc machining in end milling mode

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Advances in Manufacturing 2020年第4期8卷 508-518页

作者： Ji-peng Chen Lin Gu Wan-sheng Zhao Mario Guagliano School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037People's Republic of China Department of Mechanical Engineering Polytechnic University of MilanPiazza Leonardo da Vinci32MilanItaly State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240People's Republic of China

Blasting erosion arc machining(BEAM)is a typical arc discharge machining technology that was developed around 2012 to improve the machinability of difficult-to-cut *** milling BEAM has been successfully developed and preliminarily applied in ***,owing to the high complexity of the flow field and the difficulty of observing debris in the discharge gap,studies of the flow and debris in end milling BEAM are *** this study,fluid dynamics simulations and particle tracking are used to investigate the flow characteristics and debris ejection processes in end milling ***,the end milling BEAM m o d e is *** the numerical modeling parameters,geometric models,and simulation methods are presented in ***,the flow distribution and debris ejection are described,analyzed,and *** velocity and pressure distributions of the axial feed and radial feed are observed;the rotation speed and milling depth are found to have almost no effect on the flow velocity ***,debris is ejected more rapidly in the radial feed than in the axial *** particle kinetic energy tends to increase with increasing milling depth,and smaller particles are more easily expelled from the flushing *** study attempts to reveal the flow field properties and debris ejection mechanism of end milling BEAM,which will be helpful in gaining a better understanding of BEAM.

关键词： Modeling Flow Debris ejection Blasting erosion arc machining(BEAM) End milling

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Quantum-enhanced interferometry with asymmetric beam splitters

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Science China(Physics,Mechanics & Astronomy) 2020年第6期63卷 22-32页

作者： Wei Zhong Fan Wang Lan Zhou peng Xu YuBo sheng Institute of Quantum Information and Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093China School of Science Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China

In this paper,we investigate the phase sensitivities in two-path optical interferometry with asymmetric beam ***,we present the optimal conditions for the transmission ratio and the phase of the beam splitter to gain the highest sensitivities for a general class of non-classical states with parity ***,we address the controversial question of whether the scheme with a combination of coherent state and photon-added or photon-subtracted squeezed vacuum state is better or worse than the most celebrated one using a combination of coherent state and squeezed vacuum state.

关键词： quantum metrology quantum Fisher information Heisenberg limit optical interferometry

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Research on the architecture of submarine-fan lobes in the Niger Delta Basin,offshore West Africa

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Journal of Palaeogeography 2016年第3期5卷 185-204页

作者： Jia-Jia Zhang sheng-He Wu ting-En Fan Hong-Jun Fan Li Jiang Cheng Chen Qiong-Yuan Wu peng Lin State Key Laboratory of Petroleum Resources and Prospecting College of GeosciencesChina University of Petroleum(Beijing) Research Institute China National Offshore Oil Corporation

As one of the most important reservoirs in submarine fan, submarine lobes are hot fields for the deep-water oil-gas exploration in the world. Although a large amount of researches have been carried out on the architecture model of submarine lobes throughout the world, some controversies still exist on aspects such as the differential distribution of composite patterns and the quantitative relationships among different sedimentary settings. This paper, which took an oilfietd in the Niger Delta Basin offshore West Afnca as an example and utilized abundant core, welt-logging and seismic data comprehensively, established the semi- quantitative to quantitative architecture model for individual lobe and lobe complex. Results show that （1） A lobe complex was composed of multiple individual lobes as the compensational stacking pattern. According to the stacked relationship among individual lobes, four types of compensational stacking pattern were classified as the inordered type, the lateral migration type, the retrograding type and the prograding type. Influenced by the laterally confined degree of palaeotopography, the basin floor fan lobe complex was easily superimposed as inordered type, showing relatively large lateral width but relatively small thickness; the slope fan lobe complex was easily superimposed as lateral migration, retrograding and pro- grading types, showing relatively small lateral width but relatively large thickness. （2） Influenced by the laterally confined degree of palaeotopography, the basin floor fan individual lobes showed relatively large planar distribution area but relatively small thickness, while the slope fan individual lobes showed relatively small planar distribution area but relatively large thickness. An individual lobe was composed of multiple lobe stories by the way of aggradation-progradation pattern. From proximal to middle and distal part of individual lobes, the bottom mass-transport-deposits and the top branch channels disappeare

关键词： Submarine lobes Composite pattern Quantitative scale Niger Delta Basin West Africa

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Developing MXenes from Wireless Communication to Electromagnetic Attenuation

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Nano-Micro Letters 2021年第7期13卷 188-221页

作者： peng He Mao-sheng Cao Wen-Qiang Cao Jie Yuan School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081People’s Republic of China School of Information Engineering Minzu University of ChinaBeijing 100081People’s Republic of China

There is an urgent global need for wireless communication utilizing materials that can provide simultaneous flexibility and high *** the harmful effects of electromagnetic(EM)radiation from wireless communication is a persistent research hot ***-dimensional(2D)materials are the preferred choice as wireless communication and EM attenuation materials as they are lightweight with high aspect ratios and possess distinguished electronic ***,as a novel family of 2D materials,have shown excellent properties in various fields,owing to their excellent electrical conductivity,mechanical stability,high flexibility,and ease of *** date,research on the utility of MXenes for wireless communication has been actively ***,MXenes have become the leading materials for EM ***,we systematically review the recent advances in MXene-based materials with different structural designs for wireless communication,electromagnetic interference(EMI)shielding,and EM wave *** relationship governing the structural design and the effectiveness for wireless communication,EMI shielding,and EM wave absorption is clearly ***,our review mainly focuses on future challenges and guidelines for designing MXene-based materials for industrial application and foundational research.

关键词： MXene Wireless communication Electromagnetic wave absorption Electromagnetic interference shielding

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Microstructures and Mechanical Properties of Mg–xAl–1Sn–0.3Mn(x=1,3,5)Alloy Sheets

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Acta Metallurgica Sinica(English Letters) 2020年第9期33卷 1217-1225页

作者： Chao-Yue Zhao Xian-Hua Chen peng peng Teng Tu Andrej Atrens Fu-sheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400045China Shenyang National Laboratory for Materials Science Chongqing UniversityChongqing 400045China School of Mechanical and Mining Engineering The University of QueenslandSt LuciaQLD 4072Australia

The influence of Al alloying on the microstructures and the mechanical properties of Mg–x Al–1 Sn–0.3 Mn alloy sheets was investigated. The microstructure of Mg– x Al–1 Sn–0.3 Mn consisted of α-Mg and Mg 17 Al 12 precipitates. Alloying with Al increased the amount of Mg17Al12 and the average grain size. Uniaxial tensile tests were carried out along the extrusion direction(ED), the transverse direction(TD) and 45° toward the ED. Mg–5 Al–1 Sn–0.3 Mn alloy sheet exhibited the best combination of mechanical properties along the ED: a yield strength of 142 MPa, an ultimate tensile strength of 282 MPa and an elongation of 23%. The good performance of Mg–5 Al–1 Sn–0.3 Mn sheet was mainly attributed to the large quantity of Mg17Al12 precipitates and a weak basal texture. Annealing caused static dynamic recrystallization, refined the grain size and enhanced the mechanical properties: yield strength of 186 MPa, ultimate tensile strength of 304 MPa, elongation of 21% along ED. Both strength and ductility were enhanced by Al alloying.

关键词： Mg–xAl–1Sn–0.3Mn alloys Extrusion Microstructure Mechanical properties

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Effects of Different Weaning Protocols on Survival,Growth and Nutritional Composition of Pharaoh Cuttlefish(Sepia pharaonis)Juvenile

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Journal of Ocean University of China 2020年第6期19卷 1421-1429页

作者： JIANG Maowang HAN Ziru sheng peng peng Ruibing HAN Qingxi JIANG Xiamin Key Laboratory of Applied Marine Biotechnology School of Marine SciencesNingbo UniversityNingbo 315211China

The aim of this study was to determine the optimal weaning protocols for rearing juvenile cuttlefish Sepia pharaonis,as well as to understand the feeding habits of cuttlefish and develop effective aqua-cultural *** effects of four experimental weaning protocols(i.e.,food type,cuttlefish size,food ration(bw d^−1)and feeding frequency(meals d^−1))on the growth,survival and muscle proximate composition of cuttlefish juvenile were studied in *** weaning period lasted 2 *** results showed that cuttlefish fed with frozen white shrimp(Exopalaemon carinicauda)displayed a significantly higher survival,growth parameters,ingestion rate,food conversion rate,and muscle protein content when compared with the other prepared frozen *** larger individuals revealed better growth performance than smaller individuals,especially in terms of survival and specific growth rate,indicating that larger individuals were more receptive to frozen ***,size grading should be conducted to ensure better growth during *** food rations increased,the survival,growth and muscle protein content of juveniles were promoted,whereas the most appropriate food ration for cuttlefish juvenile was 35%bw d^−***,higher feeding frequency could stimulate the appetite of animals reared on weaning,and enhance survival,growth,and protein deposition compared to low feeding *** results suggest that the optimal feeding protocols of juvenile weaning is as follows:the ideal prepared food is frozen shrimp,the weight of juveniles should be 4.0 g(32 days old)or more,the food ration should be 35%(bw d^−1),and the optimum feeding frequency is 4 meals day^-*** study offers a promising starting point to successfully breed this candidate aquaculture species.

关键词： weaning protocols cuttlefish survival growth performance proximate composition

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High-performance doping-free carbon-nanotube-based CMOS devices and integrated circuits

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Chinese Science Bulletin 2012年第2期57卷 135-148页

作者： ZHANG ZhiYong WANG sheng peng LianMao Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking UniversityBeijing 100871China

Ballistic n-type carbon nanotube(CNT)-based field-effect transistors(FETs) have been fabricated by contacting semiconducting single-walled CNTs(SWCNTs) using Sc or *** n-type CNT FETs were pushed to their performance limits through further optimizing their gate structure and *** CNT FETs outperformed n-type Si metal-oxide-semiconductor(MOS) FETs with the same gate length and displayed better downscaling behavior than the Si MOS *** with the demonstration of ballistic p-type CNT FETs using Pd contacts,this technological advance is a step toward the doping-free fabrication of CNT-based ballistic complementary metal-oxide-semiconductor(CMOS) devices and integrated *** full advantage of the perfectly symmetric band structure of the semiconductor SWCNT,a perfect SWCNT-based CMOS inverter was demonstrated,which had a voltage gain of over *** adjacent n-and p-type FETs fabricated on the same SWCNT with a self-aligned top-gate realized high field mobility simultaneously for electrons(3000 cm2 V-1 s-1) and holes(3300 cm2 V-1 s-1).The CNT FETs also had excellent potential for high-frequency applications,such as a high-performance frequency doubler.

关键词：单壁碳纳米管 CMOS器件集成电路制造互补金属氧化物半导体兴奋剂性能 MOS场效应管场效应晶体管

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Fragility under shocking: molecular dynamics insights into defect evolutions in tungsten lattice

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Tungsten 2021年第2期3卷 234-242页

作者： peng-Jie Wang Qiang Cao sheng Liu Qing peng The Institute of Technological Sciences Wuhan UniversityWuhan 430072China Physics Department King Fahd University of Petroleum and MineralsDhahran 31261Saudi Arabia K.A.CARE Energy Research and Innovation Center at Dhahran Dhahran 31261Saudi Arabia

Tungsten has promising applications in high-radiation,high-erosion and high-impact *** peening is an effective method to enhance the surface mechanical properties of tungsten ***,the ultrafast dynamic mechanism of defect evolutions induced by laser shockwave in tungsten lattice is ***,we investigated the evolutions and interactions of various defects under ultrafast compressive process in tungsten lattice using molecular dynamic *** results confirm the brittleness of tungsten and reveal that void can reduce the yield strain and strength of the tungsten lattice by accelerating defect mesh extension and promoting the dislocation nucleation around *** density is increased with compressive strain ***,dislocation multiplication and motion reduce the elastic stage and play a dominant role during the plastic deformation of tungsten ***,void can disrupt the dislocation displacement and promote the pinning effect on dislocations by defect mesh extension.

关键词： Defect evolutions in tungsten lattice Ultrafast shock compression Pinning effect Dislocation multiplication and motion

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