检索结果-南通市图书馆

Oxidative cyclization of allyl compounds and isocyanide: A facile entry to polysubstituted 2-cyanopyrroles

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第4期35卷 330-335页

作者： Yaping Zhang wei Zhou Mingchun Gao Tianqi liu Bingxin liu Chang-hua Ding Bin Xu Department of Chemistry Affiliated Nantong Hospital of Shanghai University(The Sixth People's Hospital of Nantong)Shanghai Engineering Research Center of Organ RepairInnovative Drug Research CenterSchool of MedicineShanghai UniversityShanghai 200444China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

A facile Tf OH-catalyzed oxidative cyclization of allyl compounds and isocyanide has been developed with the assistance of DDQ, where isocyanide is used as the crucial "N" and "CN" sources. Highly functionalized 2-cyanopyrroles are constructed efficiently through a new formal [3 + 2] mode, demonstrating diverse reactivity and synthetic utility in organic chemistry. 2-Cyanopyrrole is converted into a nucleobase analogue of Remdesivir and 5H-pyrrolo[2,1-a]isoindole through a three-step or a two-step sequence, respectively. This protocol features broad substrate scope, operational simplicity and good functional group tolerance.

关键词： Isocyanide Cyanopyrrole Insertion Allyl compound Bronsted acid catalysis

Micro segment analysis of supercritical methane thermal-hydraulic performance and pseudo-boiling in a PCHE straight channel

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 1275-1289页

作者： Qian Li Zi-Jie Lin liu Yang Yue Wang Yue Li wei-hua Cai Laboratory of Thermo-Fluid Science and Nuclear Engineering Northeast Electric Power UniversityJilin132000JilinChina School of Energy and Power Engineering Northeast Electric Power UniversityJilin132000JilinChina

The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the length of 500 mm is established, with a semicircular cross section in a diameter of 1.2 *** simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel. The pseudo-boiling theory is adopted and the liquid-like, two-phase-like, and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow *** results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop. It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point. The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleateboiling-like state and heat transfer deterioration related to a film-boiling-like state. The effects of parameters, including mass flow rate, pressure, and wall heat flux on flow and heat transfer were *** calculating of the averaged heat transfer coefficient of the whole channel, the traditional method shows significant deviation and the micro segment weighted average method is adopted. The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux. The peak of the convective heat transfer coefficient can only form at high mass flux, low wall heat flux, and near critical pressure, in which condition the nucleate-boiling-like state is easier to appear. Moreover,heat transfer deterioration will always appear, since the supercritical flow will finally develop into a filmboiling-like state. So hea

关键词： Printed circuit heat exchanger Vaporization Supercritical methane Pseudo-boiling Micro segment analysis

Revisiting the island of hexadecapoledeformation nuclei in the A≈150 mass region:focusing on the model application to nuclear shapes and masses

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第2期76卷 74-88页

作者： Xiao-Yang wei hua-Lei Wang Zhen-Zhen Zhang Min-Liang liu School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China Key Laboratory of High Precision Nuclear Spectroscopy Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

Based on the potential-energy-surface calculation,the impact of different deformation degrees of freedom on a single-particle structure and binding energies in nuclei around^(152)Nd,located on one of the hexadecapole-deformation islands,is analyzed in a multi-dimensional deformation *** energy maps,curves and tables are presented to indicate nuclear *** calculated equilibrium deformations and binding energies with different potential parameters are compared with experimental data and other *** is found that the inclusion of the hexadecapole deformations,especially the axial one,can improve the theoretical description of both nuclear shapes and *** addition,our calculated potential-energy curve shows that a critical deformation-point,β_(2)≈0.4,exists—the triaxial(hexadecapole)deformation effect can be neglectable but the hexadecapole(triaxial)one plays an important role before(after)such a critical point.

关键词： hexadecapole deformation binding energy potential-energy-surface calculation nuclear property

Autofocus by Lissajous scanning in time reversal optical scanning holography

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2024年第8期22卷 13-20页

作者： Jie liu Haiyan Ou hua Wang Lin Peng wei Shao Shenzhen Institute for Advanced Study University of Electronic Science and Technology of ChinaShenzhen 518000China School of Physics University of Electronic Science and Technology of ChinaChengdu 611731China Key Laboratory of Cognitive Radio and Information Processing Guilin University of Electronic TechnologyGuilin 541004China

In this Letter, an autofocusing method in optical scanning holography(OSH) system is proposed. By introducing Lissajous scanning into multiple signal classification(MUSIC) method in time-reversal(TR) OSH, the axial locations of the targets can be retrieved with better resolution and the peak prominence increases from 0.21 to 0.34. The feasibility of this method is confirmed by simulation as well as experiment.

关键词： digital holography Lissajous scanning image reconstruction axial localization

The Q-index and Connectivity of Graphs

在线全文

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2024年第2期12卷 505-519页

作者： Peng-Li Zhang Li-hua Feng wei-Jun liu Xiao-Dong Zhang School of Mathematical Sciences MOE-LSCSHL-MACShanghai Jiao Tong UniversityShanghai 200240China School of Mathematics and Statistics Central South UniversityChangsha 410083HunanChina

A connected graph G is said to be k-connected if it has more than k vertices and remains connected whenever fewer than k vertices are *** this paper,for a connected graph G with sufficiently large order,we present a tight sufficient condition for G with fixed minimum degree to be k-connected based on the *** result can be viewed as a spectral counterpart of the corresponding Dirac-type condition.

关键词： Q-index Minimum degree k-connected

The RNA-binding domain of DCL3 is required for long-distance RNAi signaling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

aBIOTECH 2024年第1期5卷 17-28页

作者： Jie Li Bo-Sen Zhang hua-wei Wu Cheng-Lan liu Hui-Shan Guo Jian-hua Zhao State Key Laboratory of Plant Genomics Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Biotic Interactions University of the Chinese Academy of SciencesBeijing 100049China Qilu Zhongke Academy of Modern Microbiology Technology Jinan 250022China

Small RNA(sRNA)-mediated RNA silencing(also known as RNA interference,or RNAi)is a conserved mechanism in eukaryotes that includes RNA degradation,DNA methylation,heterochromatin formation and protein translation *** plants,sRNAs can move either cell-to-cell or systemically,thereby acting as mobile silencing signals to trigger noncell autonomous ***,whether and what proteins are also involved in noncell autonomous silencing have not been *** this study,we utilized a previously reported inducible RNAi plant,PDSi,which can induce systemic silencing of the endogenous PDS gene,and we demonstrated that DCL3 is involved in systemic PDS silencing through its RNA binding *** confirmed that the C-terminus of DCL3,including the predicted RNA-binding domain,is capable of binding short *** affecting RNA binding,but not processing activity,reduced systemic PDS silencing,indicating that DCL3 binding to RNAs is required for the induction of systemic *** mosaic virus infection assays showed that the RNA-binding activity of DCL3 is required for antiviral RNAi in systemically noninoculated *** findings demonstrate that DCL3 acts as a signaling agent involved in noncell autonomous silencing and an antiviral effect in addition to its previously known function in the generation of 24-nucleotide sRNAs.

关键词： RNAi signaling DCL3 RBD RNAs Cucumber mosaic virus

SnO_(2)/metal organic complex composite derived from low-temperature activated metal organic complex for advanced lithium storage

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第7期43卷 3032-3043页

作者： Gui-Long liu Zi-Han Zhao Jin-Ke Shen Zi-Bo Zhao Nai-Teng Wu Dong-Lei Guo wei-wei Yuan Yong liu Ye-hua Su Xian-Ming liu Luoyang Key Laboratory of Green Energy Materials College of Chemistry and Chemical EngineeringLuoyang Normal UniversityLuoyang 471934China School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China Inner Mongolia Shijie Chemical Co. Ltd.Alxa League 737300

Sn-based metal organic complexes with coordination bonds,multi-active sites,and high theoretical capacity have attracted much attention as promising anodes for lithium ion ***,the low electrical conductivity and huge volume changes restricted their electrochemical stability and practical ***,Snbased anode with superior electrochemical performance,including a high reversible capacity of 1050.1 mAh·g^(-1)at 2 A·g^(-1)and a stable capacity of 1105.5 mAh·g^(-1)after 500 cycles at 1 A·g^(-1),was fabricated via a low-temperature calcination strategy from Sn metal organic *** low-temperature calcination process regulates Sn-O bond and prevents the agglomeration of SnO_(2),generating highly dispersed SnO_(2) decorated metal organic complexes and providing sufficient active sites for ion *** situ characterizations expound that the undecomposed Sn-based metal organic complexes could be transformed into SnO_(2) during lithiation and delithiation,which enhances the electrical conductivity and induces a strong pseudo-capacitive behavior,accelerating the electrochemical kinetics;the multiple solid electrolyte interface with inflexible LiF and flexible ROCO_(2)Li buffers the volume variation of the electrode,resulting in its high electrochemical *** work provides a simple strategy for preparing excellent Sn-based anodes from metal organic complexes and reveals the lithium storage mechanism of the prepared Snbased anode.

关键词： Metal organic complex Lithium ion battery Electrochemical activation Low-temperature activation Partial decomposition

The dynamics beamline at SSRF

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第9期35卷 56-67页

作者： Zhen liu Li-hua Wang Yong Jiang Ya-Jun Tong hua-Chun Zhu Te Ji Min Chen Zheng Jiang Xiang-Jun wei Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China ShanghaiTech University Shanghai 201210China

The dynamics beamline(D-Line),which combines synchrotron radiation infrared spectroscopy(SR-IR)and energy-disper-sive X-ray absorption spectroscopy(ED-XAS),is the first beamline in the world to realize concurrent ED-XAS and SR-IR measurements at the same sample position on a millisecond time-resolved *** combined technique is effective for investigating rapid structural changes in atoms,electrons,and molecules in complicated disorder systems,such as those used in physics,chemistry,materials science,and extreme ***,ED-XAS and SR-IR can be used independently in the two branches of the *** ED-XAS branch is the first ED-XAS beamline in China,which uses a tapered undulator light source and can achieve approximately 2.5×10^(12)photons/s·300 eV BW@7.2 keV at the sample *** exchange-able polychromator operating in the Bragg-reflection or Laue-transmission configuration is used in different energy ranges to satisfy the requirements for beam size and energy *** focused beam size is approximately 3.5μm(H)×21.5μm(V),and the X-ray energy range is 5–25 *** one-and two-dimensional position-sensitive detectors with frame rates of up to 400 kHz enables time resolutions of tens of microseconds to be *** distinctive techniques,such as the concurrent measurement of in situ ED-XAS and infrared spectroscopy,time-resolved ED-XAS,high-pressure ED-XAS,XMCD,and pump-probe ED-XAS,can be applied to achieve different scientific goals.

关键词： ED-XAS SR-IR Time-resolved D-line SSRF

Improving flight performance of UAVs by ice shape modulation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第8期37卷 49-62页

作者： Jiajun ZHANG Xuecheng liu hua LIANG Like XIE Biao wei Haohua ZONG Yun WU Yinghong Li National Key Lab of Aerospace Power System and Plasma Technology Air Force Engineering UniversityXi’an 710038China Institute of Aero-Engine School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China

Aircraft icing poses a great threat to flight *** response to the characteristics of high-power consumption,large volume,and heavy weight of traditional anti-/de-icing technologies,the concept of ice shape modulation is proposed,which is called ice tolerant ***,the flight performance of Unmanned Aerial Vehicle(UAV)was compared in three states:no ice,full ice,and modulated ice through flight *** was found that ice shape modulation has a significant improvement effect on the aerodynamic performance of aircraft under icing *** the three modulated ice shape conditions in this experiment,the lift coefficient of the UAV under different ice shape modulation conditions increased by 18%–33%,and the stalling angle was delayed by 3°-5°.Subsequently,the pressure distribution,streamlines in the flow field,and detached vortex distribution of the UAV model in these three states were obtained through numerical simulation,to study the mechanism of ice shape modulation on the aerodynamic performance of *** simulation found that the reason for the improvement of the wings effect after ice shape modulation is that the modulated area forms a leading-edge protrusion structure similar to a vortex *** structure prolongs the mixed flow region on the wings surface and reduces the trend of flow separation,which plays a role in increasing lift and reducing drag for UAVs under icing ***,a reverse reachable set that can be used for unexpected state recovery is used as the definition of flight safety boundaries,and an aircraft dynamics model is established to obtain flight safety boundaries for different *** has found that the flight safety boundary of the UAV in a no ice state is greater than that in a modulated ice state,and the safety boundary in a modulated ice state is greater than that in a full ice *** with the full ice state,the flight safety boundary after modulation has expanded by 27.0%.The sch

关键词： Ice shape modulation Aerodynamic performance Reachable set Flight safety UAV