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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

Surface iodine and pyrenyl-graphdiyne co-modified Bi catalysts for highly efficient CO_(2) electroreduction in acidic electrolyte

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Nano Research 2024年第4期17卷 2381-2387页

作者： Min Zhang Juan wang Xin Rong xiu-Li Lu Tong-Bu Lu MOE International Joint Laboratory of Materials Microstructure Institute for New Energy Materials and Low Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China

CO_(2) electroreduction to formic acid/formate would contribute to alleviating the energy and climate *** work reports a Bi-based catalyst derived from the in-situ electroreduction of Bi_(2)O_(2)CO_(3) modified with iodine and pyrenyl-graphdiyne(PGDY)on the surface for efficient electroreduction of CO_(2) in acidic electrolyte,with a high partial current density of 98.71 mA·cm^(-2) and high Faradaic efficiency(FE)>90%over the potential range from^(-1).2 to-1.5 V *** hydrogen electrode(RHE),as well as the long-term operational stability over 240 h without degradation in H-type *** results and density function theory calculations show that the synergistic effect of surface iodine and PGDY is responsible for this active and extremely stable process of CO_(2) electroreduction via lowering the energy barriers for formation of*OCHO intermediate,suppressing the competitive HER by enhancing the concentration of both K+and CO_(2) at reaction interface,as well as preventing the dissolution and re-deposition of active Bi atoms on surface during catalytic *** work provides new insight into designing highly active and stable electrocatalysts for CO_(2) reduction.

关键词： CO_(2) reduction electrocatalysis Bi-based catalysts acidic electrolyte

In situ meso-tetra(4-carboxyphenyl)porphyrin ligand substitution in Hf-MOF for enhanced catalytic activity and stability in photoredox reactions

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Rare Metals 2024年第6期43卷 2682-2694页

作者： Jie Hu Hong-Xin Lao xiu-Wu Xu Wei-Kang wang Le-Le wang Qin-Qin Liu School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China College of Chemistry and Materials Engineering Research Center of Carbon NeutralityAnhui Normal UniversityWuhu 241002China Fujian Provincial Key Laboratory of Ecology-Toxicological Effects and Control for Emerging Contaminants Putian UniversityPutian 351100China

Though there are numerous intrinsic merits of metal-organic frameworks(MOFs),low charge separation efficiency has imposed heavy restrictions on their photocatalytic ***,in situ porphyrin ligand substitution,as a strategy for improving the charge separation efficiency and increasing the amounts of active sites,has been designed and realized in a Hf-biphenyl dicarboxylic acid(BPDC)***,a size and geometry matched meso-tetra(4-carboxyphenyl)porphyrin(TCPP)ligand was selected and doped into Hf-BPDC MOF by forming coordinating bonds with Hf centers,forming dualligand Hf-BPDC-TCPP *** resultant Hf-BPDC-TCPP MOF showed significantly improved activity and chemical stability in the photocatalytic H_(2)generation(261μmol·g^(-1)·h^(-1))and tetracycline(TC)degradation reactions(95.8%),which was 48 and 1.47 folds higher than that of the Hf-BPDC *** and electrochemical studies revealed that the introduction of porphyrin ligand could generate a stronger internal electric field for boosting the charge separation and transfer,increase the specific surface area for providing more active sites,and narrow the band gap to enhance the visible light *** in situ ligand substitution method provides a promising approach to build a tunable platform for constructing high-performance MOF photocatalysts.

关键词： Ligand substitution Metal organic frameworks Meso-tetra(4-carboxyphenyl)porphyrin Hydrogen evolution reaction Tetracycline degradation

SNR ESTIMATION AND BIT ALLOCATION APPLIED IN LOGGING TELEMETRY EQUIPMENT

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SNR ESTIMATION AND BIT ALLOCATION APPLIED IN LOGGING TELEMET...

2016年全国压电和声波理论及器件应用研讨会

作者： Lan YANG Hao CHEN xiu-ming wang Liang TANG Institute of Acoustics Chinese Academy of Sciences

ISBN: (纸本)9781509011902

Background, Motivation and Objective Orthogonal Frequency Division Multiplexing(OFDM) is one of the multi-carrier modulation techniques, which has a high spectrum efficiency and resist the channel fading effects. It divides the whole channel bandwidth into many orthogonal sub-channels, which overlap each other and transmit data simultaneously. Consequently, logging high speed data communication system is realized by OFDM technique. SNR(Signal to Noise Ratio) is a significant parameter of communication, and it has a great impact on signal quality for communication systems. The SNR estimation of channel and bit allocation are the key techniques of OFDM. SNR of each sub-carriers needs to be estimated accurately. And each sub-channels are allocated different bits on the basis of SNR. This is beneficial to make the total bits of per symbol maximal and then achieve high transmission rate. Compared with wireless channels, cable channels, for instance logging cables, change slowly. In the partial time snippet, it is regarded as a time-invariant system. Accordingly, several detecting frames are transferred firstly to estimate the channel parameters. And then the system only sends data frames. Besides, due to various non-ideal factors there is colored noise in the actual cable channel. As a result, the SNR estimation method used in cable channels is different from that in wireless channel. Statement of Contribution/Methods All the SNR estimation algorithms can be divided into data-aimed(DA) algorithms and non-data-aimed(NDA) algorithms. NDA algorithms occupy the spectrum resources, which decrease the efficiency of spectrum. This paper selects the DA estimation algorithm. Many existing DA algorithms assumed that the channel was additive white Gaussian noise channel. Accurate estimation of SNR in the cable channel wasn’t obtained by these methods. The logging cable is one of cable channels, which has colored noise and frequency-selective fading. Therefore, this paper proposes a

关键词： Data transmission Cable channel SNR estimation Bit allocation

Numerical Study on the Aerodynamic and Fluid−Structure Interaction of An NREL-5MW Wind Turbine

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China Ocean Engineering 2024年第3期38卷 363-378页

作者： ZHAO Mi YU Wan-li wang Pi-guang QU Yang DU xiu-li Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China State Key Laboratory of Bridge Engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China

A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic *** this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics(CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier-Stokes(RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid-structure interaction(FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction(FSI)model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.

关键词： computational fluid dynamics methods(CFD) tower shadow effect aerodynamic performance fluidstructure interaction space flow field

Analytical Solution and Simplified Formula for Added Mass of Horizontal and Vertical Motions of Truncated Cylinders Under Earthquake Action

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China Ocean Engineering 2024年第1期38卷 54-67页

作者： wang Pi-guang LYU Si-yu QU Yang ZHAO Mi DU xiu-li State Key Laboratory of Bridge Engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of Tech-nologyBeijing 100124China

This paper investigates the hydrodynamic characteristics of floating truncated cylinders undergoing horizontal and vertical motions due to earthquake excitations in the finite water *** governing equation of the hydrodynamic pressure acting on the cylinder is derived based on the radiation theory with the inviscid and incompressible *** governing equation is solved by using the method of separating variables and analytical solutions are obtained by assigning reasonable boundary *** analytical result is validated by a numerical model using the exact artificial boundary simulation of the infinite *** main variation and distribution characteristics of the hydrodynamic pressure acting on the side and bottom of the cylinder are analyzed for different combinations of wide-height and immersion *** added mass coefficient of the cylinder is calculated by integrating the hydrodynamic pressure and simplified formulas are proposed for engineering *** calculation results show that the simplified formulas are in good agreement with the analytical solutions.

关键词： earthquake hydrodynamic pressure truncated cylinder added mass simplified formula

ANALYSIS OF RADIAL DETECTION CHARACTERISTICS OF MONOPOLE SONIC LOGGING

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ANALYSIS OF RADIAL DETECTION CHARACTERISTICS OF MONOPOLE SON...

2016年全国压电和声波理论及器件应用研讨会

作者： Yi-han GENG Hao CHEN Xiao HE xiu-mei ZHANG xiu-ming wang University of Chinese Academy of Sciences State Key laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences

ISBN: (纸本)9781509011902

Background, Motivation and Objective Drilling causes variation of the rock properties in the vicinity of a wellbore. Usually, acoustic velocities, including P-and S-wave ones near the borehole wall are smaller than those of the virgin formation. In order to understand the velocity profile along the borehole radial direction for formation characterizations, we investigate the influence of the thickness of the transition zone on monopole longitudinal waves at varying source-to-receiver separations and frequency range based on the radial stepped sonic model. This research may be applied for radial tomography of longitudinal wave velocity with monopole logging tools. Statement of Contribution/Methods In this article, we use the radial cylindrical layered model to examine monopole logging response with a two-dimensional axisymmetric finite difference method. Three variables are set, and they are the transition zone thickness, the source frequency and source-to-receiver spacing, respectively. We also use the slowness-time correlation-method to evaluate sound speed variations under different conditions. At last, based on the ray theory, the variation characteristics of the arrival time of the first wave under different conditions are analyzed. Results For a certain source-to-receiver offset, there is a critical value for the intermediate layer thickness. When the intermediate layer thickness is less than that value, the first wave is the outermost layer formation compressional wave. When the intermediate layer thickness is greater than that value, the first wave is the compressional wave of the formation closest to the wellbore. The longitudinal waves sliding along different interfaces can be separated from each other in the time domain with the appropriate source to receiver offset. According to this result, one can possibly obtain different speeds of the intermediate layers. Meanwhile, the first wave amplitude is gradually weakened as the spacing increases. For sources w

关键词： Acoustic logging Radial detection depth Finite difference method Slowness-time correlation-method

Cone-beam computed tomography noise reduction method based on U-Net with convolutional block attention module in proton therapy

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Nuclear Science and Techniques 2024年第7期35卷 89-100页

作者： Xing-Yue Ruan xiu-Fang Li Meng-Ya Guo Mei Chen ming Lv Rui Li Zhi-Ling Chen Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai201800China University of Chinese Academy of Sciences Beijing100049China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China Department of Radiation Oncology Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai200025China Shanghai Key Laboratory of Proton therapy Shanghai201801China

Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved U-Net neural network named CBAM-U-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised U-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised U-Net network, sCTU-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-U-Net and the original sCTU-Net are called CBAM-SCT and U-Net-SCT images, respectively. The HU accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 HU, 64.63 HU, 52.27 dB, and 0.9919, respectively,which were superior to those of the U-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original U-Net and CBAM-U-Net on the dose calculation results. CBAM-U-Net reduced noise more effectively than sCTU-Net, particularly in high-density tissues. We proposed a CBAM-U-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-U-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future.

关键词： Proton therapy Cone-beam CT CBAM-U-Net γ-index

NUMERICAL ANALYSES ON THE SANDWICH DIPOLE LOGGING TRANSDUCER WITH VARIOUS LOADS

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NUMERICAL ANALYSES ON THE SANDWICH DIPOLE LOGGING TRANSDUCER...

2012全国压电和声波理论及器件技术研讨会

作者： Qiu-ying CHEN Jian-sheng CONG Xiao-min wang xiu-ming wang State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of Sciences

Numerical modeling for a sandwich dipole well logging transmitting transducer is conducted in this *** characteristics for the first-order bending vibration of the sandwich transducer within different fluid loads are numerically *** is found that the resonant frequency and transmitting voltage response level are affected by the density,acoustic velocity and acoustic impedance of the fluid *** numerical results were preliminarily vahdated by our *** numerical analyses may provide useful suggestion for both the simulation design of logging transducer and the acoustic logging applications.

关键词： Bending vibration mode Load Resonant frequency Transmitting voltage response