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Visible-light-induced Synthesis of Organic Peroxides via Decarboxylative Couplings of Carboxylic Acids, Alkenes and tert-Butyl Hydroperoxide

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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES 2024年第5期40卷 863-873页

作者： Huang, Qiuwei lou, Chenhao Lv, Leiyang Li, Zhiping Renmin Univ China Sch Chem & Life Resources Key Lab Adv Light Convers Mat & Biophoton Beijing 100872 Peoples R China

Herein, we present a photoinduced, CeCl3-catalyzed three-component decarboxylative reaction that couples carboxylic acids, alkenes and tert-butyl hydroperoxide for the formation of various organic peroxides. The ligand-to-metal charge transfer (LMCT) excitation mode allows the decarboxylative alkylation-peroxidation reaction to occur under mild conditions, and is well applicable to primary, secondary and tertiary carboxylic acids and styrene derivatives.

关键词： Visible-light catalysis Difunctionalization Carboxylic acid Alkene Organic peroxide CATALYZED CARBONYLATION-PEROXIDATION OXIDATIVE DECARBOXYLATION RADICAL-ADDITION ALDEHYDES ALKYLATION KETONES SCOPE MILD

Determination of global geodetic parameters using satellite laser ranging to Galileo,GLONASS,and BeiDou satellites

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Satellite Navigation 2024年第1期5卷 240-257页

作者： Xingxing Li Jiaqing lou Yongqiang Yuan Jiaqi Wu Keke Zhang School of Geodesy and Geomatics Wuhan University129 Luoyu RoadWuhan430079HubeiChina

The new Global Navigation Satellite System(GNSS)satellites,including GLONASS,Galileo,and BeiDou system,are equipped with Laser Retroreflector Arrays(LRA)to support Satellite Laser Ranging(SLR)tracking,which contributes to the estimation of global geodetic *** this study,we estimate the global geodetic parameters using the SLR observations to GNSS satellites and also investigate the effects of different data processing strategies on the estimated Earth Rotation Parameters(ERP),geocenter motion,and terrestrial *** results indicate that setting range bias parameters for each satellite-station pair can effectively account for the satellite-specific biases induced by LRAs,leading to smaller Root Mean Square Errors(RMSE)of the post-fit SLR ***,estimating the range biases for each satellite-station pair improves the accuracy of the estimated station coordinates and *** also examine the impact of different arc lengths on the estimates of ERP,geocenter motion,and terrestrial *** results show that extending arc length can significantly reduce the formal error of *** 7-day strategy produces the smallest RMSEs of 473 microarcseconds and 495 microarcseconds for the estimated X-and Y-component of pole coordinates,and 52 microseconds for length-of-day,***,the estimated geocenter motion is less affected by the arc length,even the shortest 1-day arc strategy can capture the seasonal variations of geocenter motion in Z *** scale estimation,extending the arc length notably improves the accuracy of the estimated station coordinates and scale,but this advantage becomes less noticeable in longer *** 7-day solution also obtains the closet scale results compared to ITRF2014,with the RMSE of 2.10×10^(–9).

关键词： Satellite laser ranging GNSS Geodetic parameters Earth rotation parameters Geocenter motion Terrestrial scale

A new 4-Ti-added polyoxometalate

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Tungsten 2024年第2期6卷 465-471页

作者： Hai-lou Li Chen Lian Guo-Yu Yang MOE Key Laboratory of Cluster Science School of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 102488China

A new inorganic–organic hybrid 4-Ti-added polyoxometalate:[H_(2)N(CH_(3))_(2)]_(2)Na_(3)H_(5)[{Ti(C_(2)O_(4))(H_(2)O)}_(2){Ti(C_(2)O_(4))}_(2)(B-β-SbW_(9)O_(33))_(2)]·22H_(2)O(1)has been successfully made and further characterized by infrared spectroscopy,thermogravimetric analysis,powder X-ray diff raction and single-crystal X-ray diff *** polyoxoanion of 1 exhibits a Krebs-type structure that is constructed from two[B-β-SbW_(9)O_(33)]^(9)−fragments fused together by a belt of four additional Ti atoms decorated by oxalate ***,1 as a heterogeneous catalyst exhibits high activity for Knoevenagel condensation under mild reaction conditions.

关键词： Polyoxometalate Ti-added POM Krebs-type structure Knoevenagel condensation

Lagrangian coherent structure analysis on transport of Acetes chinensis along coast of Lianyungang,China

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Journal of Oceanology and Limnology 2024年第1期42卷 345-359页

作者： Kexin WANG Xueqing ZHANG Qi lou Xusheng XIANG Ying XIONG College of Environmental Science and Engineering Ocean University of ChinaQingdao 266100China Key Laboratory of Marine Environment and Ecology Ministry of Education of ChinaOcean University of ChinaQingdao 266100China Jiangsu Marine Fisheries Research Institute Nantong 226007China

Spatial heterogeneity or“patchiness”of plankton distributions in the ocean has always been an attractive and challenging scientific issue to *** focused on the accumulation and dynamic mechanism of the Acetes chinensis in the Lianyungang nearshore licensed fishing *** Lagrangian frame approaches including the Lagrangian coherent structures theory,Lagrangian residual current,and Lagrangian particle-tracking model were applied to find the transport pathways and aggregation characteristics of Acetes *** exist some material transport pathways for Acetes chinensis passing through the licensed fishing area,and Acetes chinensis is easy to accumulate in the licensed fishing *** main mechanism forming this distribution pattern is the local circulation induced by the nonlinear interaction of topography and tidal *** the Lagrangian coherent structure analysis and the particle trajectory tracking indicate that Acetes chinensis in the licensed fishing area come from the nearshore *** work contributed to the adjustment of licensed fishing area and the efficient utilization of fishery resources.

关键词： plankton accumulation hydrodynamic model Lagrangian particle-tracking model Lagrangian analysis

Unusual Single Electron Transfer Reactions between Alkenes and Iodine Electrophiles

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Chinese Journal of Chemistry 2024年第5期42卷 471-477页

作者： Zhengzhao lou Jingyu Hu Chuanfa Ni Xiu Wang Jinbo Hu Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of Sciences345 Ling Ling RoadShanghai200032 China School of Physical Science and Technology ShanghaiTech University100 Haike RoadShanghai201210 China

The electrophilic addition to an alkene with an electrophile has been widely studied and applied in organic *** organic chemistry textbook describes the classical reaction between an alkene and an iodine electrophile(such as elemental iodine and N-iodosuccinimide(NIS))as a typical ionic reaction,in which an iodonium ion is formed and then attacked by a ***,in this article,we report a new and unusual reaction mode between an alkene and NIS;that is,a single electron transfer(SET)process occurs between these two reactants by forming an electron-donor acceptor *** only does this unusual single electron transfer reaction between an alkene and NIS add fundamentally important knowledge to organic chemistry,it also provides a valuable synthetic method as the new SET reaction mode with opposite regioselectivity as compared with the traditional ionic mode.

关键词： Electrophilic addition Radical ions Reaction mechanisms Alkenes Fluorine

An Efficient Smoothing and Thresholding Image Segmentation Framework with Weighted Anisotropic-Isotropic Total Variation

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1369-1405页

作者： Kevin Bui Yifei lou Fredrick Park Jack Xin Department of Mathematics University of CaliforniaIrvineIrvineCA 92697-3875USA Department of Mathematics University of North CarolinaChapel HillChapel HillNC 27599.USA Department of Mathematics and Computer Science Whittier CollegeWhittierCA 90602USA

In this paper,we design an efficient,multi-stage image segmentation framework that incorporates a weighted difference of anisotropic and isotropic total variation(AITV).The segmentation framework generally consists of two stages:smoothing and thresholding,thus referred to as smoothing-and-thresholding(SaT).In the first stage,a smoothed image is obtained by an AITV-regularized Mumford-Shah(MS)model,which can be solved efficiently by the alternating direction method of multipliers(ADMMs)with a closed-form solution of a proximal operator of the l_(1)-αl_(2) *** convergence of the ADMM algorithm is *** the second stage,we threshold the smoothed image by K-means clustering to obtain the final segmentation *** experiments demonstrate that the proposed segmentation framework is versatile for both grayscale and color images,effcient in producing high-quality segmentation results within a few seconds,and robust to input images that are corrupted with noise,blur,or *** compare the AITV method with its original convex TV and nonconvex TVP(O

关键词： Image segmentation Non-convex optimization Mumford-Shah(MS)model Alternating direction method of multipliers(ADMMs) Proximal operator

Digital signal acquisition system for complex nuclear reaction experiments

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Nuclear Science and Techniques 2024年第1期35卷 124-133页

作者： Wei-Liang Pu Yan-Lin Ye Jian-Ling lou Jia-Hao Chen School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871China Institute of Applied Physics and Computational Mathematics Beijing 100094China

A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control *** proposed digital system can be combined with a conventional analog data acquisition system to provide more *** performance of the combined system was veri-fied using experimental data.

关键词： Digital signal acquisition system Trigger Programmable logic Timestamp

Impact of EnKF assimilating Himawari-8 all-sky infrared radiance on the forecasting of a warm-sector rainstorm event

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Science China Earth Sciences 2024年第10期67卷 3110-3127页

作者： Shanshan lou Lei ZHU Xuexing QIU Guangzhou CHEN Song YUAN Shengnan ZHOU Anhui Meteorological Observatory Hefei 230031China Key Laboratory of Meteorological Disaster Ministry of Education(KLME)Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Joint International Research Laboratory of Climate and Environment Change(ILCEC)Nanjing University of Information Science&TechnologyNanjing 210044China Huaihe River Basin Meteorological Center Hefei 230031China Shouxian National Climatology Observatory Huaihe River Basin Typical Farm Eco-Meteorological Experiment Field of CMAShouxian National Comprehensive Meteorological Observation Special Experimental OutfieldShouxian 232200China Anhui Province Key Laboratory of Atmospheric Science and Satellite Remote Sensing Hefei 230031China

Warm-sector rainstorms are highly localized events, with weather systems and triggering mechanisms are not obvious,leading to limited forecasting capabilities in numerical models. Based on the ensemble Kalman filter(PSU-En KF) assimilation system and the regional mesoscale model WRF, this study conducted a simulation experiment assimilating all-sky infrared(IR)radiance for a warm-sector rainstorm in East China and investigated the positive impact of assimilating the Himawari-8 moisture channel all-sky IR radiance on the forecast of the rainstorm. Results indicate that hourly cycling assimilation of all-sky IR radiance can significantly improve the forecast accuracy of this warm-sector rainstorm. There is a notable increase in the Threat Score(TS), with the simulated location and intensity of the 3-hour precipitation aligning more closely with observations. These improvements result from the assimilation of cloud-affected radiance, which introduces more mesoscale convective information into the model's initial fields. The adjustments include enhancements to the moisture field, such as increased humidity and moisture transport, and modifications to the wind field, including the intrusion of mid-level cold air and the strengthening of lowlevel convergent shear. These factors are critical in improving the forecast of this warm-sector rainstorm event.

关键词： Ensemble Kalman filter WRF model Himawari-8 All-sky radiance Warm-sector rainstorm

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Overview of computation strategies on the dispersion analysis for explicit finite difference solution of acoustic wave equation

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Petroleum Science 2024年第4期21卷 2311-2328页

作者： Jian-Ping Huang Wei-Ting Peng Ji-Dong Yang Lu-Feng lou School of Geosciences China University of Petroleum (East China) Pilot National Laboratory for Marine Science and Technology (Qingdao)

Finite-difference(FD) method is the most extensively employed numerical modeling technique. Nevertheless, when using the FD method to simulate the seismic wave propagation, the large spatial or temporal sampling interval can lead to dispersion errors and numerical instability. In the FD scheme, the key factor in determining both dispersion errors and stability is the selection of the FD weights. Thus,How to obtain appropriate FD weights to guarantee a stable numerical modeling process with minimum dispersion error is critical. The FD weights computation strategies can be classified into three types based on different computational ideologies, window function strategy, optimization strategy, and Taylor expansion strategy. In this paper, we provide a comprehensive overview of these three strategies by presenting their fundamental theories. We conduct a set of comparative analyses of their strengths and weaknesses through various analysis tests and numerical modelings. According to these comparisons, we provide two potential research directions of this field: Firstly, the development of a computational strategy for FD weights that enhances stability; Secondly, obtaining FD weights that exhibit a wide bandwidth while minimizing dispersion errors.

关键词： Finite-difference scheme FD coefficients Dispersion error Forward modeling Numerical simulation