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Organic Chemistry Frontiers 2022年第1期9卷 95-101页

作者： Haoxiang Zhang mengze Liang Xiao Zhang meng-ke he Chao Yang Lin Guo Wujiong Xia State key Lab of Urban Water Resource and Environment School of ScienceHarbin Institute of Technology(Shenzhen)Shenzhen518055China Wenzhou University WenzhouZhejiang 325000China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiangHenan 453007China

An electrochemical defluorinative alkylation protocol ofα-trifluoromethyl alkenes is *** reaction enables the preparation of functionalized gem-difluoroalkenes with the use of diverse alkyl sources including organohalides,N-hydroxyphthalimide(NHP)esters and Katritzky *** method exhibits lots of synthetic advantages including mild conditions,simple operation,and convenience of amplification,and provides a new route for the synthesis of gem-difluoroalkenes。

关键词： synthesis alkyl alkylation

Incidence Coloring of Outer-1-planar Graphs

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 840-848页

作者： meng-ke QI Xin ZHANG School of Mathematics and Statistics Xidian UniversityXi'an 710071China

A graph is outer-1-planar if it can be drawn in the plane so that all vertices lie on the outer-face and each edge crosses at most one another *** is known that every outer-1-planar graph is a planar *** this paper,we conjecture that every planar graph G has a proper incidence(Δ(G)+2)-coloring and confirm it for outer-1-planar graphs with maximum degree at least 8 or with girth at least ***,we prove that every outer-1-planar graph G has an incidence(Δ(G)+3,2)-coloring,and every outer-1-planar graph G with maximum degree at least 8 or with girth at least 4 has an incidence(Δ(G)+2,2)-coloring.

关键词： incidence coloring outer--planar graph planar graph

Effect of heat Treatment on Gradient Microstructure and Tensile Property of Laser Powder Bed Fusion Fabricated 15-5 Precipitation Hardening Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 181-195页

作者： Sheng Cao Hongyu Liu Jin Jiang ke he Binghua Lv Hao Zhang Lujie Zhang Jingrong meng Hao Deng Xiaodong Niu Department of Mechanical Engineering College of EngineeringShantou UniversityShantou515063China China State Shipbuilding Co. Ltd.Huangpu Wenchong Shipbuilding Company Ltd.Guangzhou510715China Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing100080China Shantou Ruixiang Mould Co. Ltd.Shantou515041China Military Representative Office X of Unit 93147 Deyang618000China China National Erzhong Group Co. Deyang Wanhang Die Forging Co.Ltd.Deyang618013China

This work investigated the gradient microstructure evolution and tensile property of LPBF fabricated 15-5 precipitation hardening stainless steel in post-process direct ageing(DA)and solution treating&ageing(STA).The varied microstructures for austenite and small-sized oxide inclusions at different sample heights in the as-built(AB)condition was generally preserved after DA ***,austenite was almost disappeared,and oxide particle grew significantly after the STA *** a result,the tensile property differences in sample top and bottom for AB and DA conditions did not occur in the STA *** the influence of post-process heat treatment,the STA condition had the highest yield strength due to the highest volume fraction of nano-sized Cu ***,the DA specimen had the highest ultimate tensile strength and elongation owing to the considerable amount of austenite phase and associated transformation induced plasticity effect.

关键词： 15-5 PH stainless steel Laser powder bed fusion heat treatment Gradient microstructures Tensile properties

Two Monte Carlo-based simulators for imaging-system modeling and projection simulation of flat-panel X-ray source

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Nuclear Science and Techniques 2024年第7期35卷 31-46页

作者： meng-ke Qi Ting he Yi-Wen Zhou Jing Kang Zeng-Xiang Pan Song Kang Wang-Jiang Wu Jun Chen Ling-Hong Zhou Yuan Xu School of Biomedical Engineering Southern Medical UniversityGuangzhou510515China State key Laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou510275China Department of Radiotherapy Guangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhou510515China

The advantages of a flat-panel X-ray source(FPXS)make it a promising candidate for imaging *** imaging-system modeling and projection simulation are critical for analyzing imaging performance and resolving overlapping projection issues in *** conventional analytical ray-tracing approach is limited by the number of patterns and is not applicable to FPXS-projection ***,the computation time of Monte Carlo(MC)simulation is independent of the size of the patterned arrays in *** study proposes two high-efficiency MC projection simulators for FPXS:a graphics processing unit(GPU)-based phase-space sampling MC(gPSMC)simulator and GPU-based fluence sampling MC(gFSMC)*** two simulators comprise three components:imaging-system modeling,photon initialization,and physical-interaction simulations in the ***-system modeling was performed by modeling the FPXS,imaging geometry,and *** gPSMC simulator samples the initial photons from the phase space,whereas the gFSMC simulator performs photon initialization from the calculated energy spectrum and fluence *** entire process of photon interaction with the geometry and arrival at the detector was simulated in parallel using multiple GPU kernels,and projections based on the two simulators were *** accuracies of the two simulators were evaluated by comparing them with the conventional analytical ray-tracing approach and acquired projections,and the efficiencies were evaluated by comparing the computation *** results of simulated and realistic experiments illustrate the accuracy and efficiency of the proposed gPSMC and gFSMC simulators in the projection calculation of various phantoms.

关键词： Flat-panel X-ray source(FPXS) Imaging-system modeling Projection simulation Monte Carlo-based simulators

In situ direct reprogramming of astrocytes to neurons via polypyrimidine tract-binding protein 1 knockdown in a mouse model of ischemic stroke

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Neural Regeneration Research 2024年第10期19卷 2240-2248页

作者： meng Yuan Yao Tang Tianwen Huang Lining ke En Huang key Laboratory of Brain Aging and Neurodegenerative Diseases of Fujian Province Fujian Medical UniversityFuzhouFujian ProvinceChina Department of Human Anatomy School of Basic Medical SciencesFujian Medical UniversityFuzhouFujian ProvinceChina Scientific Research Center School of Basic Medical SciencesFujian Medical UniversityFuzhouFujian ProvinceChina Department of Neurology Fujian Medical University Union HospitalFuzhouFujian ProvinceChina Fujian key Laboratory of Vascular Aging Fujian Medical UniversityFuzhouFujian ProvinceChina

In situ direct reprogramming technology can directly convert endogenous glial cells into functional neurons in vivo for central nervous system repair. Polypyrimidine tract-binding protein 1(PTB) knockdown has been shown to reprogram astrocytes to functional neurons in situ. In this study, we used AAV-PHP.e B-GFAP-sh PTB to knockdown PTB in a mouse model of ischemic stroke induced by endothelin-1, and investigated the effects of GFAP-sh PTB-mediated direct reprogramming to neurons. Our results showed that in the mouse model of ischemic stroke, PTB knockdown effectively reprogrammed GFAP-positive cells to neurons in ischemic foci, restored neural tissue structure, reduced inflammatory response, and improved behavioral function. These findings validate the effectiveness of in situ transdifferentiation of astrocytes, and suggest that the approach may be a promising strategy for stroke treatment.

关键词： astrocyte in situ direct reprogramming ischemic stroke miR-30 based shRNA neuron polypyrimidine tract-binding protein 1 transdifferentiation

Axial enantiomers with donor-regulated TADF feature for multicolor circularly polarized electroluminescence

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Science China Chemistry 2024年第6期67卷 2039-2045页

作者： Chen-Hao Guo Wen-Long Zhao ke-ke Tan Wei-Chen Guo Liheng Feng Chuan-Feng Chen meng Li School of Chemistry and Chemical Engineering Shanxi UniversityTaiyuan030006China Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

This study optimized the TADF feature of axial chiral enantiomers through precise donor engineering,and multicolor CP-TADFwas achieved in the axial chiral *** pairs of axial enantiomers with donor-regulated TADF feature,namely(R/S)-TPCBD,(R/S)-DPCBD,and(R/S)-DPACBD,were synthesized by introducing carbazole donors with different substituents onto biphenyl cyanide *** the electron-donating ability of donors increases,the emission of these axial enantiomers ranges from 455,476 to 552 nm,their singlet-triplet energy gaps(ΔE_(ST))gradually decrease from 0.30,0.22 to 0.02 e V,accompanied by an increasement in the transition rate(k_(RISC))of RISC process,and the k_(RISC)of DPACBD could reach up to 7.16×10^(5)s^(-1).These axial enantiomers also exhibit mirror-image CD and circularly polarized luminescence(CPL)***,OLEDs based on TPCBD,DPCBD,and DPACBD as emitter were then fabricated,which displayed blue,green,and orange electroluminescence with EQE_(max)of 13.0%,16.4%,and 25.0%,*** results also exhibited a phenomenon of device efficiency increasing with the enhancement of donor ***,the CP-OLEDs using(R/S)-TPCBD,(R/S)-DPCBD and(R/S)-DPACBD as emitters displayed intense CPEL signals with g_(EL)values of 3.4×10^(-3)/-4.1×10^(-3),3.2×10^(-3)/-3.1×10^(-3)and2.3×10^(-3)/-2.1×10^(-3),*** convenient molecular engineering of donor regulation in the same molecular skeleton,CP-TADF materials with multicolor CPEL and improved device performance could be conveniently achieved.

关键词： axial chirality thermally activated delayed fluorescence circularly polarized luminescence electroluminescence organic light-emitting diodes

Proppant transport in rough fracture networks using supercritical CO_(2)

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Petroleum Science 2024年第3期21卷 1852-1864页

作者： Yong Zheng meng-meng Zhou Ergun Kuru Bin Wang Jun Ni Bing Yang ke Hu Hai Huang Hai-Zhu Wang School of Petroleum Engineering Xi'an Shiyou UniversityXian710065ShaanxiChina Shaanxi key Laboratory of Carbon Dioxide Sequestration and Enhanced Oil Recovery Xi'an710075ShaanxiChina State key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China School of Mining and Petroleum Engineering University of AlbertaEdmontonTG2W2AlbertaCanad Shaanxi Yanchang Petroleum(Group)Co. Ltd.Xi'an710075ShaanxiChina

Proppant transport within fractures is one of the most critical tasks in oil,gas and geothermal reservoir stimulation,as it largely determines the ultimate performance of the operating *** transport in rough fracture networks is still a relatively new area of research and the associated transport mechanisms are still *** this study,representative parameters of rough fracture surfaces formed by supercritical CO_(2) fracturing were used to generate a rough fracture network model based on a spectral synthesis *** fluid dynamics(CFD)coupled with the discrete element method(DEM)was used to study proppant transport in this rough fracture *** reveal the turning transport mechanism of proppants into branching fractures at the intersections of rough fracture networks,a comparison was made with the behavior within smooth fracture networks,and the effect of key pumping parameters on the proppant placement in a secondary fracture was *** results show that the transport behavior of proppant in rough fracture networks is very different from that of the one in the smooth fracture *** turning transport mechanisms of proppant into secondary fractures in rough fracture networks are gravity-driven sliding,high velocity fluid suspension,and fracture structure *** the same injection conditions,supercritical CO_(2)with high flow Reynolds number still has a weaker ability to transport proppant into secondary fractures than *** of the supercritical CO_(2)needs to be increased beyond a certain value to have a significant effect on proppant carrying,and under the temperature and pressure conditions of this paper,it needs to be increased more than 20 times(about 0.94 m Pa s).Increasing the injection velocity and decreasing the proppant concentration facilitates the entry of proppant into the branching fractures,which in turn results in a larger stimulated reservoir *** results help to understand the pro

关键词： Reservoir stimulation CCUS Rough fracture network Supercritical CO_(2) Proppanttransport

Physical Prediction Model of Compound Hydrodynamic Unload-Load Response Ratio and Its Application in Reservoir Colluvium Landslide

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Journal of Earth Science 2024年第4期35卷 1304-1315页

作者： Lu Guo keqiang he Honghua Liu Fandi meng Xuchun Wang School of Civil Engineering Qingdao University of TechnologyQingdao266520China key Laboratory of Geological Safety of Coastal Urban Underground Space Ministry of Natural ResourcesQingdao266071China

It is well known that the deformation and damage of reservoir colluvium landslides are often determined by the combined dynamics of reservoir water level change and *** on the systematic analysis of the change law of reservoir water level,rainfall and displacements of reservoir colluvium landslide,this paper proposes the compound hydrodynamic action of rainfall and reservoir water as the unload-load parameter,and the landslide displacement as the unload-load response *** on this,a physical prediction model of the compound hydrodynamic unload-load response ratio of reservoir colluvium landslide was established,and the quantitative relationship between the compound hydrodynamic unload-load response ratio and its stability evolution was in-depth analyzed and *** the basis of the above research,taking Shuping landslide,a typical hydrodynamic pressure landslide as an example,the unload-load response ratio model is used to systematically evaluate and predict the stability evolution law and the change trend of the landslide under compound hydrodynamic *** prediction result shows that the variation law of the compound hydrodynamic unload-load response ratio is consistent with the dynamic evolution law of its ***,the above studies show that the compound hydrodynamic unload-load response ratio parameter is an effective displacement dynamic evaluation parameter for reservoir colluvium landslides,so it can be used in the prediction of the reservoir colluvium landslides.

关键词： landslides reservoir colluvium landslide compound hydrodynamics unload-load response ratio Shuping landslide stability evaluation

Morphological Evolution of Self-Assembled Sodium Dodecyl Sulfate/Dodecyltrimethylammonium Bromide@Epoxy-β-Cyclodextrin Supramolecular Aggregates Induced by Temperature

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Journal of Renewable Materials 2024年第4期12卷 629-641页

作者： Qingran meng Wenwen Xu Zuobing Xiao Qinfei ke Xingran Kou key Laboratory of Textile Science&Technology Ministry of EducationCollege of TextilesDonghua UniversityShanghai201620China Collaborative Innovation Center of Fragrance Flavor and Cosmetics School of Perfume and Aroma Technology(Shanghai Research Institute of Fragrance&Flavour Industry)Shanghai Institute of TechnologyShanghaiChina

Bio-based cyclodextrins(CDs)are a common research object in supramolecular *** special cavity structure of CDs can form supramolecular self-assemblies such as vesicles and microcrystals through weak interaction with guest *** different forms of supramolecular self-assemblies can be transformed into each other under certain *** regulation of supramolecular self-assembly is not only helpful to understand the self-assembly principle,but also beneficial to its *** the present study,the self-assembly behavior of epoxy-β-cyclodextrin(EP-β-CD)and mixed anionic and cationic surfactant system(sodium dodecyl sulfate/dodecyltrimethylammonium bromide,SDS/DTAB)in aqueous solution was *** and particle size characterization found that the SDS/DTAB@EP-β-CD complex,as the basic building unit,self-assembled into worm-like micelles at lower temperatures and vesicles at higher *** magnetic resonance(NMR)and Fourier transform infrared spectroscopy(FT-IR)analysis revealed that the driving force for the formation of vesicles and worm-like micelles was the hydrogen bonds between EP-β-CD molecules,while water molecules played an important role in promoting vesicle formation between SDS/DTAB@EP-β-CD ***,the mechanism of the morphologic transformation of SDS/DTAB@EP-β-CD supramolecular aggregates induced by temperature was elucidated by exploring the self-assembly process,which may provide an excellent basis for the development of delivery carriers.

关键词： Epoxy-β-cyclodextrin SDS/DTAB self-assembly temperature morphological evolution

A Dual Domain Robust Reversible Watermarking Algorithm for Frame Grouping Videos Using Scene Smoothness

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Computers, Materials & Continua 2024年第6期79卷 5143-5174页

作者： Yucheng Liang ke Niu Yingnan Zhang Yifei meng College of Cryptographic Engineering Engineering University of the Chinese People’s Armed Police ForceXi’an710086China key Laboratory of Information Security of the Chinese People’s Armed Police Force Engineering University of the Chinese People’s Armed Police ForceXi’an710086China

The proposed robust reversible watermarking algorithm addresses the compatibility challenges between robustness and reversibility in existing video watermarking techniques by leveraging scene smoothness for frame grouping *** in the H.264 video coding standard,the algorithm first employs traditional robust watermark stitching technology to embed watermark information in the low-frequency coefficient domain of the U ***,it utilizes histogram migration techniques in the high-frequency coefficient domain of the U channel to embed auxiliary information,enabling successful watermark extraction and lossless recovery of the original video *** results demonstrate the algorithm’s strong imperceptibility,with each embedded frame in the experimental videos achieving a mean peak signal-to-noise ratio of 49.3830 dB and a mean structural similarity of *** with the three comparison algorithms,the performance of the two experimental indexes is improved by 7.59%and 0.4%on *** the same time,the proposed algorithm has strong robustness to both offline and online attacks:In the face of offline attacks,the average normalized correlation coefficient between the extracted watermark and the original watermark is 0.9989,and the average bit error rate is *** the face of online attacks,the normalized correlation coefficient between the extracted watermark and the original watermark is 0.8840,and the mean bit error rate is *** with the three comparison algorithms,the performance of the two experimental indexes is improved by 1.27%and 18.16%on average,highlighting the algorithm’s ***,the algorithm exhibits low computational complexity,with the mean encoding and the mean decoding time differentials during experimental video processing being 3.934 and 2.273 s,respectively,underscoring its practical utility.

关键词： Robust reversible watermarking scene smoothness dual-domain U channel H.264 encoding standard