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A highly efficient La-modified ZnAl-LDO catalyst and its performance in the synthesis of dimethyl carbonate from methyl carbamate and methanol

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Chinese Journal of Chemical Engineering 2023年第9期61卷 9-23页

作者： Mingxue Yin bo Jia Kuiyi You bo Jin Yangqiang Huang Xiao luo Zhiwu Liang College of Chemistry and Chemical Engineering the Engineering Research Center of Advanced CatalysisMinistry of EducationHunan UniversityChangsha 410082China College of Chemical Engineering Xiangtan UniversityXiangtan 411105China

In this paper,the highly efficient ZnAlLa layered double oxide(ZnAlLa-LDO)catalyst was evaluated and used in methyl carbamate(MC)alcoholysis synthesis of dimethyl *** optimal conditions,the MC conversion was 33.5% and the dimethyl carbonate(DMC)selectivity was up to 92,4% at 443 K and in 9 *** prepared catalysts were well characterized to investigate the effect on the catalytic performance and reaction catalysis *** experimental results show that the addition of La adjusted the structure and chemical properties of ZnAl composite oxide and that the synergistic effect among Zn,Al and La play a key role in adjusting the acid-base properties and stability of the catalyst,which definitely improved the DMC selectivity and catalytic *** on the proposed reaction mechanism,two kinetic models of the catalytic reaction were established and modified:LangmuirHinshelwood and power-rate law kinetic *** good agreement between kinetic models and experimental data showed that the power-rate law kinetic model based on the elementary reactions is a suitable model for providing a theoretical *** pre-exponential factor and activation energy of the main reaction are 5.77×10^(7)and 77.60 kJ·mol^(-1),respectively.

关键词： Methanol Urea alcoholysis Dimethyl carbonate Kinetic model

Recent advances in the construction of axially chiral arylpyrroles

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Science China Chemistry 2023年第9期66卷 2480-2491页

作者： Yang-bo Chen Ye-Nan Yang Xuan-Zhu Huo long-Wu Ye bo Zhou Key Laboratory of Chemical Biology of Fujian Province State Key Laboratory of Physical Chemistry of Solid SurfacesCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Catalytic enantioselective preparation of axially chiral molecules has gained considerable interest over the past decades, due to their numerous applications in bioactive molecules, natural products, pharmaceuticals, materials, ligands, and catalysts. Compared with the well-established synthetic approaches for six-membered axially chiral skeletons, methodologies directed towards five-membered axially chiral compounds are relatively rare. Among these, axially chiral arylpyrroles are especially important structural motifs with wide utility, and the atroposelective synthesis of them is highly desirable. In recent years, novel strategies have been developed based on transition-metal catalysis and organocatalysis. This review summarizes the recent achievements in atroposelective preparation of arylpyrroles, by emphasizing the synthetic methods for each axially chiral framework, reaction mechanisms, and applications.

关键词： axial chirality pyrrole atropisomers transition-metal catalysis organocatalysis

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Collective motion in non-reciprocal swarms

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控制理论与应用（英文版） 2009年第2期7卷 105-111页

作者： bo LIU Tianguang CHU long WANG College of Science North China University of Technology Beijing 100041 China Intelligent Control Laboratory Center for Systems and Control College of Engineering and Key Laboratory of Machine Perception （Ministry of Education） Peking University Beijing 100871 China

This paper studies a non-reciprocal swarm model that consists of a group of mobile autonomous agents with an attraction-repulsion function governing the interaction of the agents. The function is chosen to have infinitely large values of repulsion for vanishing distance between two agents so as to avoid occurrence of collision. It is shown analytically that under the detailed balance condition in coupling weights, all the agents will aggregate and eventually form a cohesive cluster of finite size around the weighted center of the swarm in a finite time. Moreover, the swarm system is completely stable, namely, the motion of all agents converge to the set of equilibrium points. For the general case of non-reciprocal swarms without the detailed balance condition, numerical simulations show that more complex self-organized oscillations can emerge in the swarms. The effect of noise on collective dynamics of the swarm is also examined with a white Gaussian noise model.

关键词： Aggregation Collective behaviour Collision avoidance Complete stability Self-organized oscillation

Blended skip entry guidance for low-lifting lunar return vehicles

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Acta Mechanica Sinica 2014年第6期30卷 973-982页

作者： Zong-Fu luo Hong-bo Zhang Guo-Jian Tang College of Aerospace Science and Engineering National University of Defense Technology

A skip entry guidance algorithm blending numerical predictor-corrector and nominal trajectory tracking is presented for lunar return *** guidance is decoupled into longitudinal and lateral channels.A piecewise bank-vs-energy magnitude profile and a sign profile are adopted in the skip phase.A magnitude parameter is used to adjust the predicted downrange,and a pseudo-crossrange at the beginning of the final phase is selected as the lateral control *** biases of both channels are nullified by a false position iteration *** on-line estimation and modeling method is introduced to compensate for aerodynamic and atmospheric uncertainties.A nominal trajectory for the final phase is generated based on actual reenter conditions,and the obtained nominal trajectory is tracked by a linear feedback law.A lateral corridor is used to manage the lateral *** proposed guidance algorithm is assessed using three-degree-of-freedom Monte Carlo analyses,and the results show a satisfactory and robust performance under highly stressful dispersions.

关键词： Skip entry guidance Numerical predictorcorrector Low-lifting vehicle Lunar return mission Bank profile

Metabolic assessement of spleen infiltration by non-Hodgkin lymphoma using ^(18)F-FDG PET/CT:Preliminary clinical results

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Nuclear Science and Techniques 2009年第4期20卷 235-242页

作者： SUN long PAN Weimin luo Zuoming WEI Jihong ZHAO long WU Hua Minnan PET Center and Department of Nuclear Medicine No.1 Hospital of Xiamen Fujian Medical University Xiamen 316003 China

18F-FDG PET/CT was used for evaluation of spleen infiltration in patients with B-cell non-Hodgkin lymphoma(NHL).Five patients with histological diagnosed B-cell NHL underwent1 8F-FDG PET/CT *** integrated PET/CT image,spleen infiltration was considered when PET images revealed a discrete margin of solid splenic masses or diffuse lesion of spleen with higher maximum standardized uptake value(SUV) greater than those of normal liver *** images demonstrating a positive splenic index(>480 mL)or focal hypodensities were classified as positive for spleen *** the patients underwent systemic ***1 8F-FDG PET and CT results were compared with final *** patients had spleen infiltration originating from B-cell NHL at final *** diagnoses,which were confirmed by clinical and CT(n=3) or1 8F-FDG PET/CT(n=1) follow-up in 4 patients and biopsy of 1 *** integrated PET/CT image,1 8F-FDG PET was true-positive in all 5 patients with spleen *** was true-positive in 4 of the 5 patients with spleen infiltration and false-negative in 1 patients (spleen infiltration without morphology changes).The accuracies of1 8F-FDG PET and CT for evaluating the spleen infiltration were 100% and 80% at staging,*** preliminary results suggested metabolic imaging of1 8F-FDG PET/CT may be helpful in the diagnosis of spleen infiltration in B-cell NHL *** patients may benefit from1 8F-FDG PET/CT in diagnosis,when spleen infiltration without morphology changes,which may not be diagnosed exactly by conventional image.

关键词： SUV ^18F-FDG PET/CT 能级原子核物理学

Influence of the Electrical Vehicle Charging on the Grid Harmonic

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Journal of Electronic Science and Technology 2017年第1期15卷 99-105页

作者： Cheng-long Xia Yong-Duan Song Yang luo School of Energy Science and Engineering University of Electronic Science and TechnologyChengdu 611731China

This paper described the impact of the electrical vehicle（EV） charging on the grid harmonic. In view of the randomness of the EV charging process, the harmonic admittance matrix method and superposition method were used to build the single and multiple EVs charging simulation model. By using Matlab as a simulation tool, we analyzed harmonic currents of single and multiple EVs chargers. The results show that the harmonic ratio is beyond the scope of the national harmonic standard. Finally a parallel hybrid active filter（PHAPF） was introduced for governance of *** experimental results show that net side harmonic currents are significantly reduced by using the PHAPF and meet the national standard GB/Z17625.6-2003 regulations limit.

关键词： harmonic superposition charging currents governance regulations battery impedance rectifier beyond

Effect of heat treatment on the microstructure and micromechanical properties of the rapidly solidified Mg61.7Zn34Gd4.3 alloy containing icosahedral phase

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International Journal of Minerals,Metallurgy and Materials 2019年第7期26卷 869-877页

作者： Wen-bo luo Zhi-yong Xue Wei-min Mao School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Institute for Advanced Materials North China Electric Power University Beijing 102206 China School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206 China

In this paper, the microstructure evolution of the rapidly solidified (RS) Mg61.7Zn34Gd4.3 (at%, atomic ratio) alloy at high temperatures was investigated. The hardness and elastic modulus of the main precipitated phases were also analyzed and compared with those of the α-Mg matrix on the basis of nanoindentation tests. The results show that the RS alloy consists of either a petal-like icosahedral quasicrystal (IQC) phase (~20 μm) and block-shaped H1 phase (~15 μm) or IQC particles with an average grain size of ~107 nm as well as a small proportion of amorphous phase, which mainly depends on the holding time at the liquid temperature and the thickness of the ribbons. The IQC phase gradually transforms at 400?C to a short-rod-shaped μ-phase (Mg28.6Zn63.8Gd7.7) with a hexagonal structure. The hardness of the IQC phase is higher than that of H1 phase, and both phases exhibit a higher hardness than the α-Mg matrix and the μ-phase. The elasticity of the H1 phase is superior to that of the α-Mg matrix. The IQC phase possesses a higher elastic modulus than H1 phase. The easily formed H1 phase exhibits the poorest plastic deformation capacity among these phases but a higher elastic modulus than the α-Mg matrix.

关键词： magnesium alloy icosahedral phase rapidly solidification nanoindentation micromechanical properties

B-C-N Compounds with Mixed Hybridization of sp^(2)-Like and sp^(3)-Like bonds

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Chinese Physics Letters 2012年第3期29卷 161-164页

作者： luo Xiao-Guang HE Ju-long Department of Electronics College of Information Technical ScienceNankai UniversityTianjin 300071 State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004

We perform first-principles calculations of the structural and electronic properties of hypothetical bc6-BC_(4)N and N-substituted bc6-BC4N,which are derived from a body-center-cubic carbon *** calculations show that the former is a semiconductor with an indirect band gap of 0.91 eV and the latter is *** calculated bond length,bond population,and charge density of N-substituted bc6-BC4N indicate that one C-N bond has been broken after N-substitution,which means that the structure contains a mixed hybridization of sp^(2)-like and sp^(3)-1ike *** the pressure above 100 GPa,the structure changes to a pure sp^(3)-like hybridization.

关键词： structure substituted bonds

The Join of Split Graphs Whose Half-strong Endomorphisms Form a Monoid

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Acta Mathematica Sinica,English Series 2010年第6期26卷 1139-1148页

作者： Hai long HOU Yah Feng luo Rui GU School of Mathematics and Statistics He 'nan University of Science and Technology Luoyang 471003 P. R. China Department of Mathematics Lanzhou University Lanzhou 730000 P. R. China School of Mathematics and Statistics He 'nan University of Science and Technology Luoyang 471003 P. R. China

In this paper, the half-strong endomorphisms of the join of split graphs are investigated. We give the conditions under which the half-strong endomorphisms of the join of split graphs form a monoid.

关键词： half-strong endomorphism monoid split graph join of graphs