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Copper-catalyzed C–H bond functionalization enabled by programmed alternating current

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Science China Chemistry 2025年第1期68卷 10-11页

作者： Zhoumei Tan Kun Xu Chengchu zeng Beijing Key laboratory of Environmental and Viral Oncology College of Chemistry and Life Science Beijing University of Technology

Synthetic electrochemistry has been selected as one of the Top Ten Emerging Technologies in Chemistry in 2023 by International Union of Pure and Applied Chemistry (IUPAC)[1]. It has emerged as a sustainable platform for organic synthesis and has exhibited a wide range of applications from academia to industry [2]. However, electrosynthesis has been predominantly performed by using direct current (DC).

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Inexact proximal gradient algorithm with random reshuffling for nonsmooth optimization

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Science China(Information Sciences) 2025年第1期68卷 219-237页

作者： Xia JIANG yanyan FANG Xianlin zeng Jian SUN Jie CHEN National Key lab of Autonomous Intelligent Unmanned Systems School of AutomationBeijing Institute of Technology Beijing Institute of Technology Chongqing Innovation Center School of Electronic and Information Engineering Tongji University

Proximal gradient algorithms are popularly implemented to achieve convex optimization with nonsmooth regularization. Obtaining the exact solution of the proximal operator for nonsmooth regularization is challenging because errors exist in the computation of the gradient; consequently, the design and application of inexact proximal gradient algorithms have attracted considerable attention from researchers. This paper proposes computationally efficient basic and inexact proximal gradient descent algorithms with random reshuffling. The proposed stochastic algorithms take randomly reshuffled data to perform successive gradient descents and implement only one proximal operator after all data pass through. We prove the convergence results of the proposed proximal gradient algorithms under the sampling-without-replacement reshuffling *** computational errors exist in gradients and proximal operations, the proposed inexact proximal gradient algorithms can converge to an optimal solution neighborhood. Finally, we apply the proposed algorithms to compressed sensing and compare their efficiency with some popular algorithms.

关键词： proximal operator random reshuffling inexact computation compressed sensing nonsmooth optimization

Design and Application of Turbine Cascade Partitioned Endwall Profiling

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Journal of Thermal Science 2025年第1期34卷 110-128页

作者： zeng Fei JIANG Ruiqi XUE Xingxu DU Wei lUO lei ZHOU Xun AECC Hunan Aviation Powerplant Research Institute School of Energy Science and Technology Harbin Institute of Technology Science and Technology on Diesel Engine Turbocharging laboratory China North Engine Research Institute

The influence of partitioned profiling design based on a large-pitch highly loaded cascade is studied by numerical *** partitioned profile is mainly composed of a pressure-side convex structure near the leading edge and a suction-side convex structure at the midstream and downstream sides of the *** influence of the change in the vertex axial position and peak value of the B-line on the secondary flow control is *** this paper,air(ideal gas) is selected as the flow *** average static pressure at the outlet and the average total temperature at the inlet are kept *** γ-θ is used as the turbulence *** results show that the pressure-side convex structure suppresses the spanwise and pitchwise migration of the inlet flow by adjusting the static pressure distribution of the flow field,so the development of the pressure-side leg of the horseshoe vortex is effectively *** suction-side convex structure adjusts the static pressure distribution of the flow field and increases the included angle between the cross-flow and suction surface,so the accumulation of low-momentum fluid,the development of a corner vortex and the flow separation at the trailing edge of the suction-side surface are all suppressed near the endwall-suction ***,the energy loss coefficient of the large-pitch highly loaded cascade is decreased from 0.0564 to 0.0485,representing a 25% reduction in secondary flow losses.

关键词： Vortex flow

ATOMIZATION CAUSED By BOTTOM FlOW ENERGy DISSIPATION

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Journal of Hydrodynamics 2001年第1期13卷 23-27页

作者： Hu, M.l. liang, Z.C. zeng, y.H. Wuhan Univ. of Hydraulic and Electr. Wuhan 430072 China

Bottom flow energy dissipation is one of the common energy dissipation methods for flood-releasing structures with high water head. Measures of this energy dissipation depend mainly on the turbulent action of hydraulic jump. In this paper, the physical process and the calculating methods of the atomization caused by bottom flow energy dissipation were studied, the computation models of atomization quantity for the self-aerated flow in overflow and hydraulic jump regions are presented, and the main results are of theoretical and practical significance for the hydraulic and electric engineering.

关键词： Energy dissipation Hydraulic jump Hydrodynamics

Differential Evolution of High-Pressure and Ultrahigh-Pressure Metapelites from Habutengsu, Chinese Western Tianshan: Phase Equilibria Modelling and ^(40)Ar/^(39)Ar Geochronology

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Acta Geologica Sinica(English Edition) 2016年第2期90卷 628-640页

作者： lü zeng ZHANG lifei The Key laboratory of Orogenic Belts and Crustal Evolution School of Earth and Space SciencesPeking University

Metapelite is one of the predominant rock types in the high-pressure–ultrahigh-pressure（HP–UHP） metamorphic belt of western Tianshan, NW China; however, the spatial and temporal variations of this belt during metamorphism are poorly understood. In this study, we present comparative petrological studies and 40^Ar/39 ^Ar geochronology of HP and UHP pelitic schist exposed along the Habutengsu valley. The schist mainly comprises quartz, white mica, garnet, albite and bluish amphibole. In the Mn O–Na2O–Ca O–K2O–Fe O–Mg O–Al2O3–Si O2–H2O（Mn NCKFMASH） system, P–T pseudosections were constructed using THERMOCAlC 333 for two representative pelitic schists. The results demonstrate that there was a break in the peak metamorphic pressures in the Habutengsu area. The northern schist has experienced UHP metamorphism, consistent with the presence of coesite in the same section, while the southern one formed at lower pressures that stabilized the quartz. This result supports the previous finding of a metamorphic gradient through the HP–UHP metamorphic belt of the Chinese western Tianshan by the authors. Additionally, phengite in the northern schist was modelled as having a Si content of 3.55–3.70（a.p.f.u.） at the peak stage, a value much higher than that of oriented matrix phengite（Si content 3.32–3.38 a.p.f.u.）. This indicates that the phengite flakes in the UHP schist were subjected to recrystallization during exhumation, which is consistent with the presence of phengite aggregates surrounding garnet porphyroblast. The 40^Ar/39^ Ar age spectra of white mica（dominantly phengite） from the two schists exhibit similar plateau ages of ca. 315 Ma, which is interpreted as the timing of a tectonometamorphic event that occurred during the exhumation of the HP–UHP metamorphic belt of the Chinese western Tianshan.

关键词： pelitic schist HP–UHP metamorphism P–T pseudosection 40^Ar/39^Ar geochronology Chinese western Tianshan

Activatable chemiluminescence probe based on four-arm PEGconjugated-pyropheophorbide-a for in vivo autofluorescence-free imaging of peroxynitrite

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Science China Chemistry 2025年

作者： Jianmei Ke lei Ding Ronggui lian Cheng Zheng Wenjun li Aixian Zheng yupeng Sun Ming Wu yongyi zeng Xiaolong liu Maochun Hong Xiaolong Zhang The United Innovation of Mengchao Hepatobiliary Technology Key laboratory of Fujian Province Mengchao Hepatobiliary Hospital of Fujian Medical University Ganjiang Innovation Academy Chinese Academy of Sciences School of Rare Earths University of Science and Technology of China College of Chemistry Fuzhou University State Key laboratory of Structure Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Peroxynitrite（ONOO-） is a highly reactive nitrogen species that plays pivotal roles in cell signal transduction and physiological or pathological progresses. However, commonly used ONOO-optical imaging probes are still hampered by high background/autofluorescence（fluorescence probe）, short emission wavelength, or poor selectivity in the case of chemiluminescence. Herein,we report a facile method to prepare an activatable chemiluminescence probe（PPA-PEG） with good biocompatibility and functionality for in vivo autofluorescence-free imaging of ONOO-. The PPA-PEG consists of pyropheophorbide-a（PPA）, a typical deep red photosensitizer that acts as both the recognition and signaling element, and 4-arm poly（ethylene glycol）(4-arm PEG), which improves the biosafety and water solubility of probe. These components can self-assemble into nanoparticles（namely PPA-PEG nanoprobe） in aqueous solution. The PPA-PEG nanoprobe showed an ultra-low chemiluminescence signal before interacting with ONOO-, but exhibited good selectivity, high sensitivity and a fast response toward ONOO-. The PPAPEG was successfully applied to image cellular ONOO-changes, as well as the endogenous ONOO-changes in inflammation models and subcutaneous or orthotopic hepatocellular carcinoma（HCC） tumors models in living mice. In vitro and in vivo studies verified the good detection and imaging capabilities of PPA-PEG for peroxynitrite, demonstrating suitable tissue penetration and a high signal-to-background ratio（SBR）. Thus, our nanoprobe can serve as a valuable activatable chemiluminescence imaging tool for studying important peroxynitrite-related chemical and biological applications.

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Reducing metal artifacts by restricting negative pixels

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Visual Computing for Industry,Biomedicine,and Art 2021年第1期4卷 142-151页

作者： Gengsheng l.zeng Megan zeng Department of Computer Science Utah Valley UniversityOremUT 84058USA Department of Radiology and Imaging Sciences University of UtahSalt Lake CityUT 84108USA Department of Electrical Engineering and Computer Science University of California at BerkeleyBerkeleyCA 94720USA

When the object contains metals,its x-ray computed tomography(CT)images are normally affected by streaking *** artifacts are mainly caused by the x-ray beam hardening effects,which deviate the measurements from their true *** interesting observation of the metal artifacts is that certain regions of the metal artifacts often appear as negative pixel *** novel idea in this paper is to set up an objective function that restricts the negative pixel values in the *** must point out that the naïve idea of setting the negative pixel values in the reconstructed image to zero does not give the same *** paper proposes an iterative algorithm to optimize this objective function,and the unknowns are the metal affected *** the metal affected projections are estimated,the filtered backprojection algorithm is used to reconstruct the final *** paper applies the proposed algorithm to some airport bag CT *** bags all contain unknown metallic *** metal artifacts are effectively reduced by the proposed algorithm.

关键词： Filtered backprojection image reconstruction Iterative algorithm Metal artifact reduction Objective function X-ray computed tomography

SyNTHESIS　AND　ANTI－HIV－1　ACTIVITy　OF　HETEROPOly　COMPlEXES　OF　TUNGSTOTITANOPHOSPHATES　CONTAINING　RARE　EARTH　ElEMENTS

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Chinese Chemical letters 1996年第8期7卷 777-778页

作者： liu, SX li, BT Wang, l liu, yy Wang, EB zeng, y li, Zl NE NORMAl UNIV DEPT CHEMCHANGCHUN 130024PEOPLES R CHINA CHINESE ACAD PREVENT MED BEIJING 100050PEOPLES R CHINA

The present paper rePOrts nine new heteropoly compounds of tungstotitanophosphates containing rare earth elements, i. e., ln2H[PTi2W10O40]. xH2O (ln=la,Ce, Pr, Nd, Sm, Gd, Tb, yb, lu). The above compounds have shown g... 详细信息

关键词： HIV-1

Effects of Growth Temperature on Structural and Electrical Properties of li-N-H Codoped ZnO

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Journal of Materials Science & Technology 2013年第2期29卷 154-156页

作者： y.F. lu Z.Z. ye l.P. Zhu y.J. zeng J.y. Huang B.H. Zhao State Key laboratory of Silicon Materials Department of Materials Science and Engineering Zhejiang University

Effects of growth temperature on the structural and electrical properties of li-N-H codoped ZnO thin films grown by DC reactive magnetron sputtering were investigated. Scanning electron microscopy and X-ray diffraction results showed that increasing growth temperature could improve the crystalline quality. But Hall measurement results showed that growth temperature had a nonlinear influence on the electrical property. The variation of electrical properties with the growth temperature was found to be related to the activated concentration of N in ZnO and the evaporation of li during the growth process, derived from the Hall measurement and the second ion mass spectroscopy measurement.

关键词： ZnO Codoped Growth temperature Structural property Electrical property