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Silver-catalyzed unstrained C(CO)–alkyl bond scission via[3+2]/retro-[3+2]cycloaddition of ketones with N-isocyanoiminotriphenylphosphorane

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Science China Chemistry 2021年第7期64卷 1157-1163页

作者： Zikun Wang Linxuan Li xueying zhang Xihe Bi Department of Chemistry Northeast Normal UniversityChangchun 130024China State Key Laboratory of Elemento-Organic Chemistry Nankai UniversityTianjin 300071China

C(CO)–alkyl bonds are ubiquitous in a variety of organic molecules,and their selective activation and functionalization are important for the reconstruction of simple ketones into valuable building ***,due to the thermodynamic and kinetic stability,the cleavage and transformation of the unstrained C(CO)–alkyl bonds remain a significant ***,we report a novel silver-catalyzed scission of the unstrained C(CO)–alkyl bond of ketones by reacting with N-isocyanoiminotriphenylphosphorane(NIITP)under mild *** method could transform a variety of unstrained ketones into iminophosphoranes and nitriles in high *** and computational studies disclosed the reaction proceeded through an unprecedented[3+2]/retro-[3+2]cycloaddition mechanism.

关键词： silver-catalyzed C-C bond scission unstrained ketones tertiary alcohol intermediates cycloaddition

Deep learning models for spatial relation extraction in text

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Geo-Spatial Information Science 2023年第1期26卷 58-70页

作者： Kehan Wu xueying zhang Yulong Dang Peng Ye Key Laboratory of Virtual Geographic Environment(Nanjing Normal University) Ministry of EducationNanjingChina Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application NanjingChina Urban Planning and Development Institute Yangzhou UniversityYangzhouChina College of Civil Science and Engineering Yangzhou UniversityYangzhouChina

Spatial relation extraction is the process of identifying geographic entities from text and determining their corresponding spatial *** spatial relation extraction mainly uses rule-based pattern matching,supervised learning-based or unsupervised learning-based ***,these methods suffer from poor time-sensitive,high labor cost and high dependence on large-scale *** the development of pre-trained language models greatly alleviating the shortcomings of traditional methods,supervised learning methods incorporating pre-trained language models have become the mainstream relation extraction *** extraction and joint extraction,as the two most dominant ideas of relation extraction,both have obtained good performance on different datasets,and whether to share the contextual information of entities and relations is the main differences between the two *** this paper,we compare the performance of two ideas oriented to spatial relation extraction based on Chinese corpus data in the field of geography and verify which method based on pre-trained language models is more suitable for Chinese spatial relation *** fine-tuned the hyperparameters of the two models to optimize the extraction accuracy before the comparison *** results of the comparison experiments show that pipeline extraction performs better than joint extraction of spatial relation extraction for Chinese text data with sentence granularity,because different tasks have different focus on contextual information,and it is difficult to take account into the needs of both tasks by sharing contextual *** addition,we further compare the performance of the two models with the rule-based template approach in extracting topological,directional and distance relations,summarize the shortcomings of this experiment and provide an outlook for future work.

关键词： Spatial relation extraction pre-trained language model pipeline extraction joint extraction

Thermodynamic simulations of pellet internal target in CSRm

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Science China(Physics,Mechanics & Astronomy) 2005年第5期48卷 529-540页

作者： LI Zhankui XU Hushan zhang xueying Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China

Pellet target with a close to 4π detector configuration is an optional effective internal target in the storage ring CSRm. Thermodynamic simulations are carried out to describe the hydrogen microsphere behaviors in the whole moving path, and the temperature and mass changes of hydrogen microspheres are clearly indicated. The achievable experimental luminosity by pellet target in CSRm is calculated to be 1×1033 cm?2·s?1 at most.

关键词： internal target, pellet target, evaporative cooling, luminosity.

Representation type of local and two-vertex bocses

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Science China Mathematics 2009年第5期52卷 949-958页

作者： zhang xueying zhang YingBo ZHAO ShuangMei School of Mathematical Sciences Beijing Normal UniversityBeijing 100875China

Let k be an algebraically closed field. It has been proved by zhang and Xu that if a bocs is of tame representation type, then the degree of the differential of the first solid arrow must be less than or equal to 3. We will prove in the present paper that: The bocs is still wild when the degree of the differential of the first arrow is equal to 3. Especially, the bocs with only one solid arrow is of tame type if and only if the degree of the differential of the arrow is less than or equal to 2. Moreover, we classify in this case the growth problems of the representation category of the bocs and layout the sufficient and necessary conditions when the bocs is of finite representation type, tame domestic and tame exponential growth respectively.

关键词： bocs reduction tame representation type wild representation type domestic 15A21 16G20 16G60 16G70

Seasonal variations of leaf wax n-alkane distributions and δ^(2) H values in peat-forming vascular plants from the Dajiuhu peatland, central China

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Frontiers of Earth Science 2022年第3期16卷 774-785页

作者： Jiantao XUE xueying zhang Jinzhi LI Zhiqi zhang Huaiying YAO Research Center for Environmental Ecology and Engineering School of Environmental Ecology and Biological EngineeringWuhan Institute of TechnologyWuhan 430073China Administration of Dajiuhu National Wetland Park of Shennongjia Shennongjia 442417China Key Laboratory of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China

Leaf wax n-alkane compositions have been widely applied to reconstruct paleoclimate histories in peat deposits,yet understanding of how the n-alkanes vary during seasonal plant growth remains *** we report variations in the molecular and wax-derived nalkane hydrogen isotope(δ^(2) Halk)in the three dominant vascular plant species(Sanguisorba officinalis,Carex argyi,Euphorbia esula)and surface peat deposits nearby from the Dajiuhu peatland over a growing *** three species show a relatively high carbon preference index(CPI)in the beginning of the growing season,with the CPI values reaching as high as 50 in two of the three *** species(***,***)display relatively stable average chain length(ACL)values over the four sampling intervals,with standard derivations of *** contrast,*** exhibits a significant fluctuation of ACL values(averaging 28.11.4)over the growing ***δ^(2) Halk in all three species decreased during leaf *** the final stage of growth,theδ^(2) Halk values of the three species are similar to those in the surface peats collected from the *** the results of our measurements of alkane concentration andδ^(2) H values,it is likely that de novo synthesis of leaf wax n-alkanes in the peatforming plant species is mainly at the early stage of leaf *** the following months,the removal process exceeds renewal,resulting in a general decrease of the concentration of the total n-alkanes and the integratedδ^(2) Halk *** theδ^(2) Halk values probably integrate the environmental variations at the end of the plant growth period rather than the whole period or the early growth *** results are significant and have the potential to improve the utility ofδ^(2) Halk values in paleoenvironmental reconstructions.

关键词： peat-forming vascular plants n-alkanes δ^(2)H ratio seasonal variations central China

Study on Processing Conditions of Aluminum Matrix Composites Reinforced with Boron Carbide Particles

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Journal of Rare Earths 2004年第z2期22卷 61-64页

作者： Fu xueying zhang Hong Xi Huizhi Yi Xiaosu Material Department Harbin Engineering UniversityHarbin 150001China National Key Laboratory of Advanced Composites Beijing Institute of Aeronautical MaterialsBeijing 100095China National Key Laboratory of Advanced CompositesBeijing Institute of Aeronautical MaterialsBeijing 100095China Material DepartmentHarbin Engineering UniversityHarbin 150001China National Key Laboratory of Advanced CompositesBeijing Institute of Aeronautical MaterialsBeijing 100095China

Different pre-heating of boron carbide particles for reinforcement and different processing conditions were studied in this work. Being one of the most cost-effective industrial methods, conventional melt stir-casting route was *** showed that the boron carbide particles distributed well for a suitable pre-heating temperature and processed in *** reaction product was found at the A1-B4C interfaces at the resolution limit of SEM used in that way.

关键词： aluminum matrix composites boron carbide stir casting processing conditions

Silicalite-1 zeolite encapsulated Fe nanocatalyst for Fenton-like degradation of methylene blue

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Chinese Journal of Chemical Engineering 2023年第1期53卷 251-259页

作者： Hongwei Guo Linyuan Chen xueying zhang Huanhao Chen Yan Shao State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China School of Environmental Science and Engineering Nanjing Tech UniversityNanjing 211816China

Encapsulation of Fe nanoparticles in zeolite is a promising way to significantly improve the catalytic activity and stability of Fe-based catalysts during the degradation process of organic ***,Fe nanocatalysts were encapsulated into silicalite-1(S-1)zeolite by using a ligand-protected method(with dicyandiamide(DCD)as a organic ligand)under direct hydrothermal synthesis ***-resolution transmission electron microscopy(HRTEM)results confirmed the high dispersion of Fe nanocatalysts which were successfully encapsulated within the voids among the primary particles of the S-1 *** developed S-1 zeolite encapsulated Fe nanocatalyst(Fe@S-1)exhibited significantly improved catalytic activity and reusability in the catalytic degradation process of methylene blue(MB).Specifically,the developed Fe0.021@S-1 catalyst showed high catalytic degradation activity,giving a high MB degradation efficiency of 100%in 30 min,outperformed the conventional impregnated catalyst(Fe/S-1).Moreover,the Fe@S-1 catalyst afforded an outstanding stability,showing only ca.7.9%activity loss after five cycling tests,while the Fe/S-1 catalyst presented a significantly activity loss of 50.9%after only three ***,the encapsulation strategy enabled a relatively lower Fe loading in the Fe@S-1 catalyst in comparison with that of the Fe/S-1 catalyst,i.e.,0.35%vs.0.81%(mass).Radical scavenging experiments along with electron spin resonance(ESR)measurements confirmed that the major role ofOH in the MB degradation ***,Fe@S-1 catalyst with high molar ratio of[Fe(DCD)]Cl3 is beneficial to form Fe complexes/nanoclusters in the voids(which has large pore size of 1–2 nm)among the primary particles of the zeolite,and thus improving the diffusion and accessibility of reactants to Fe active sites,and thus exhibiting a relatively higher degradation *** work demonstrates that zeolite-encapsulated Fe nanocatalysts present potential applications in the

关键词： Zeolite Encapsulation Fe nanocatalyst Degradation Methylene blue

Comparative Study on the Antioxidant Activity of Peptides from Pearl Oyster(Pinctada martensii) Mantle Type V Collagen and Tilapia(Oreochromis niloticus) Scale Type Ⅰ Collagen

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Journal of Ocean University of China 2017年第6期16卷 1175-1182页

作者： XIA Guanghua zhang xueying DONG Zhenghua SHEN Xuanri College of Food Science and Technology Hainan University Haikou 570228 P. R. China

In this study, Pearl oyster mantle type V collagen(POMC) and tilapia scale type I collagen(TSC) were extracted and hydrolyzed by various proteases in order to obtain peptides. The antioxidant activity of the peptides was investigated by DPPH, hydroxyl radical scavenging experiments and a dynamic digestion model in vitro. The results show that there are significant differences in amino acid composition between POMC and TSC. The collagen peptides obtained from pearl oyster mantle(POMCP) by treating with alkaline protease exhibited higher antioxidant activity than that from tilapia scale(TSCP) treated with papaya protease, and both of them showed greater DPPH and hydroxyl radical scavenging activity than other peptides. After being separated via Sephadex G-25 chromatography, the M1 fraction isolated from POMCP, and the S1 fraction from TSCP with which both had higher molecular weights showed the strongest antioxidant activity than other fractions, and the M1 fraction exhibited stronger antioxidant activity than the S1 fraction in scavenging free-radicals and protecting cells from the oxidation damage. Furthermore, after treating the dynamic digestion system model in vitro, the DPPH and hydroxyl radical scavenging activity of the M1 fraction increased slightly. These results suggest that POMCP exhibits stronger antioxidant activity than TSCP, which means that PMOP may be a good candidate to be a potential natural antioxidant in the food-processing industry.

关键词： tilapia scale pearl oyster mantle collagen peptide antioxidant activity

Stroke Electroencephalogram Data Synthesizing through Progressive Efficient Self-Attention Generative Adversarial Network

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Computers, Materials & Continua 2024年第10期81卷 1177-1196页

作者： Suzhe Wang xueying zhang Fenglian Li Zelin Wu College of Electronic Information Engineering Taiyuan University of TechnologyTaiyuan030024China

Early and timely diagnosis of stroke is critical for effective treatment,and the electroencephalogram(EEG)offers a low-cost,non-invasive ***,the shortage of high-quality patient EEG data often hampers the accuracy of diagnostic classification methods based on deep *** address this issue,our study designed a deep data amplification model named Progressive Conditional Generative Adversarial Network with Efficient Approximating Self Attention(PCGAN-EASA),which incrementally improves the quality of generated EEG *** network can yield full-scale,fine-grained EEG features from the low-scale,coarse ***,to overcome the limitations of traditional generative models that fail to generate features tailored to individual patient characteristics,we developed an encoder with an effective approximating self-attention *** encoder not only automatically extracts relevant features across different patients but also reduces the computational resource ***,the adversarial loss and reconstruction loss functions were redesigned to better align with the training characteristics of the network and the spatial correlations among *** experimental results demonstrate that PCGAN-EASA provides the highest generation quality and the lowest computational resource usage compared to several existing ***,it significantly improves the accuracy of subsequent stroke classification tasks.

关键词： Data augmentation stroke electroencephalogram features generative adversarial network efficient approximating self-attention