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Equivariant eta forms and equivariant differential K-theory

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Science China Mathematics 2021年第10期64卷 2159-2206页

作者： bo liu School of Mathematical Sciences Shanghai Key Laboratory of PMMPEast China Normal UniversityShanghai 200241China

In this paper,we propose a new numerical scheme for the coupled Stokes-Darcy model with the Beavers-Joseph-Saffman interface *** use the weak Galerkin method to discretize the Stokes equation and the mixed finite element method to discretize the Darcy equation.A discrete inf-sup condition is proved and the optimal error estimates are also *** experiments validate the theoretical analysis.

关键词： equivariant eta form equivariant differential K-theory equivariant spectral section equivariant higher spectral flow orbifold

Total synthesis of proposed structures ofjiangrines C and D

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Science China Chemistry 2016年第9期59卷 1205-1210页

作者： Zhijiang Zhang bo liu Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University Chengdu 610064 China State Key Laboratory of Natural Medicines China Pharmaceutical University Nanjing 210009 China

On the basis of the proposed structures of jiangrines C and D, a synthetic strategy was initiated from D-glyceraldehyde acetonide,a readily available chiral material. Through a linear seven-step synthesis, the target molecules were accomplished. However, all characteristic data of the synthetic 3 and 4 were found to be different from those of natural jiangrines C and D. Accordingly, the molecular structures of jiangrines should be revised and a possible molecular skeleton for them was proposed.

关键词： pyrrole alkaloid jiangrine total synthesis

Numerical Investigation and Non-Axisymmetric Endwall Profiling of a Turbine Stage

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Journal of Thermal Science 2019年第4期28卷 811-825页

作者： REHMAN Abdul liu bo School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China Shaanxi Key Laboratory of Internal Aerodynamics in Aero-Engine Xi’an 710072China

This paper presents an optimization of a high pressure turbine by constructing non-axisymmetric endwalls to the stator row and the rotor *** optimization was quantified by using optimization algorithms based on the multi-objective *** objective was to increase total-to-total efficiency with the constraint on the mass flow rate equal to the design point *** order to ensure that global optimum could be achieved,the function of parameters was first approximated through the artificial neural network,and then optimum was achieved by implementing the genetic *** was adopted through the design and optimization environment of FineTM/Design3 *** individual treatments of the endwalls were ***,the hub and the shroud of the stator were optimized ***,the hub of the rotor was ***,the rotor hub was optimized in the presence of the optimized *** result of the investigation showed that the optimized shape of the endwalls can significantly help to increase the efficiency up to 0.18%with the help of a reduction of the transverse pressure *** coefficient of secondary kinetic energy,entropy coefficient,spanwise mass averaged entropy were *** order to investigate the periodic effects,the design of the optimized turbine under steady simulations was confirmed through unsteady *** last part of the investigation made sure that the performance improvement remained consistent over the full operating line at off-design conditions by the implementation of non-axisymmetric endwalls.

关键词： optimization non-axisymmetric endwall high pressure turbine stage efficiency secondary kinetic energy steady unsteady off-design

Joint timing synchronization and frequency offset acquisition algorithm for MIMO OFDM systems

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Journal of Systems Engineering and Electronics 2009年第3期20卷 470-478页

作者： liu Qi Hu bo Dept. of Electronic Engineering Fudan Univ. Shanghai 200433 P. R. China

For multiple-input multiple-output （MIMO） orthogonal frequency division multiplexing （OFDM） systems, a joint timing synchronization and frequency offset acquisition algorithm based on fractional Fourier transform （FRFT） is proposed. The linear frequency modulation signals superimposed on the data signals are used as the training signals. By performing FRFT on the received signals and searching the peak value of the FRFT results, the receiver can realize timing synchronization and frequency offset acquisition simultaneously. Compared with the existing methods, the proposed algorithm can provide better timing synchronization performance and larger frequency offset acquisition range even under multi-path channels with low signal to noise ratio. Theoretical analysis and simulation results prove this point.

关键词： multiple-input multiple-output orthogonal frequency division multiplexing timing synchronization frequency offset acquisition fractional Fourier transform.

Theoretical Prediction of Differential Cross Sections for Reaction pp → pK^＋A in a Resonance Model

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Communications in Theoretical Physics 2006年第3X期46卷 501-506页

作者： liu bo-Chao Institute of High Energy Physics the Chinese Academy of Sciences P.O. Box 918 (4) Beijing 100049 China Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China Institute of Theoretical Physics the Chinese Academy of Sciences Beijing 100080 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China

The reaction of pp → pK^＋A is a very good channel to study N^＊ resonances through their KA decay mode, because there is no mixing of isospin I = 1/2 and I = 3/2 due to isospin conservation. In this work, we extend a resonance model, which can reproduce the total cross section very well, to offer differential cross section information about this reaction. It can serve as a reference to build the scheduled hadron detector at Lanzhou Cooler Storage Ring （CSR）. Experiment measurement of these differential cross sections in the future will supply us more constraints on the model and help us understanding the strangeness production dynamics better.

关键词： resonance model pp collision

Chiral Pool Guided Syntheses of Polycyclic Natural Products

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Chinese Journal of Chemistry 2022年第3期40卷 407-418页

作者： Shaomin Fu bo liu Key Laboratory of Green Chemistry&Technology of Ministry of Education College of ChemistrySichuan University29 Wongjiang Rd.ChengduSichuan 610064China

Chiral pools have been commonly utilized as inexpensive and versatile building blocks in organic *** this account,we provide an overview of our recent synthetic efforts toward polycyclic natural products using chiral natural small molecules(chiral pool)as starting *** achievements during our syntheses include intermolecular Diels-Alder/intramolecular hetero-Diels-Alder cascade to enable modification of previously proposed biosynthetic pathway of bolivianine,Diels-Alder-type dimerization through a conjugated furanyl diene intermediate to achieve three types of lindenane[4+2]dimers,Iron-catalyzed reductive aldol reaction to construct core of rumphellclovane E and[3,3]-rearrangement along with vinylo-gous Pummerer rearrangement to make epoxyquinol substructure of JBIR-23/-*** the final,the outlook is also presented.

关键词： Chiral pool Natural products Total synthesis Polycylic Cascade reaction

Tracking the Tectonic Evolution of the Junggar-Balkhash Ocean: A Case Study from the Post-Collisional Takergan Pluton in the West Junggar, Xinjiang

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Journal of Earth Science 2021年第5期32卷 1250-1261页

作者： Yangbaihe Hong bo liu Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines Department of GeologySchool of Resources and Civil EngineeringNortheastern UniversityShenyang 110819China

The Late Carboniferous and Early Permian igneous rocks are widely developed in the West Junggar, Xinjiang, which are considered to be related to the evolution of the Junggar-Balkhash Ocean. However, their tectonic settings have been controversial for a long time. With the aim of providing new evidence for the Late Paleozoic tectonic evolution of the West Junggar, we present petrology, zircon U-Pb chronology, whole-rock major and trace elemental and Sr-Nd isotopic data, to discuss the petrogenesis and tectonic setting of Takergan pluton from the Barleik Mountains in the West Junggar. The Takergan pluton is mainly composed of quartz diorite porphyry and quartz monzonite. The quartz diorite porphyry has low Si O2(57.76 wt.%–57.81 wt.%), high total alkali contents(Na2 O+K2 O=6.29 wt.%–6.56 wt.%), and high Mg# values(45–46), with a zircon U-Pb age of 304±5 Ma. The quartz monzonite shows relatively high SiO2(58.71 wt.%–64.71 wt.%), total alkali contents(7.73 wt.%–9.70 wt.%), and Mg^(#) values(34–47), with the A/CNK values of 0.91–0.98, which belongs to shoshonitic and metaluminous I-type granite series. The quartz monzonite yields zircon U-Pb ages of 302±2 and 296±3 Ma, and is characterized by low initial Sr ratios of 0.703 97–0.704 09, high εNd(t) values of +6.8– +7.0, and young Nd model ages of 551–587 Ma. both the quartz diorite porphyry and quartz monzonite are enriched in light rare earth elements and Rb, Th, U, K, and depleted in Nb, Ta, Ti, with different degrees of negative Eu anomalies. These features indicate that the Takergan pluton was most likely formed in a post-collisional setting by partial melting of a depleted mantle source that had been metasomatized by subduction-related fluids, with significant fractional crystallization and slightly contaminated by crustal materials. Combined with the widespread distribution of the coeval stitching plutons, the occurrences of terrestrial Late Carboniferous to Permian volcano-sedimentary formations, and the absence of

关键词： Junggar-Balkhash Ocean post-collisional magmatism central Asian orogenic belt West Junggar

C^1 conforming quadrilateral finite elements with complete secondorder derivatives on vertices and its application to Kirchhoff plates

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Science China(Technological Sciences) 2020年第6期63卷 1066-1084页

作者： WU Yang XING YuFeng liu bo Institute of Solid Mechanics Beihang UniversityBeijing 100191China

The classical problem of the construction of C^1 conforming single-patch quadrilateral finite elements has been solved in this investigation by using the blending function interpolation *** order to achieve the C^1 conformity on the interfaces of quadrilateral elements,complete second-order derivatives are used at the element vertices,and the information of geometrical mapping is also considered into the construction of shape *** is found that the shape functions and the polynomial spaces of the present elements vary with element ***,the developed quadrilateral elements are at least third order for general quadrilateral shapes and fifth order for rectangular ***,very fast convergence can be achieved.A promising feature of the present elements is that they can be used in cooperation with those high-precision rectangular and triangular *** the present elements are over conforming on element vertices,an approach for handling problems of material discontinuity is also *** examples of Kirchhoff plates are employed to demonstrate the computational performance of the present elements.

关键词： finite element method quadrilateral elements C^1 conforming Kirchhoff plates

Microwave Assisted-extraction of Flavonols from Acanthopanax Senticosus Harms and High-performance Liquid Chromatography Analysis

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Chemical Research in Chinese Universities 2009年第4期25卷 439-442页

作者： liu Yan-bo Department of Chemistry Baicheng Teacher＇s College Baicheng 137000 P. R. China

Flavonols were extracted from Acanthopanax Senticosus Harms by Soxhlet extraction（SE）,atmospheric pressure microwave-assisted extraction（AMAE） and pressurized microwave-assisted extraction（PMAE）.The influences of experimental conditions,such as concentration of ethanol in the eluent,microwave irradiation time,*** the extraction yield were *** flavonols（hyperin,rutin,quercitrin and quercetin） in the extracts were determined quantitatively by HPLC *** experimental results demonstrate the advantages of PMAE and AMAE over those of conventional SE,that is the extraction time is dramatically reduced,and the yields of flavonols are effective *** the yield of flavonols is higher and the extraction time is shorter by PMAE than those of AMAE,flavonols are easy to be decomposed over a certain time.

关键词： Acanthopanax Senticosus Harms Flavonols Extraction