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The orientational preferences of backbones of proteins

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Chinese Science Bulletin 2006年第21期51卷 2559-2565页

作者： chen ying WANG jun XUE Bin WANG Wei National Laboratory of Solid State Microstructure Department of Physics and Institute of Biophysics Nanjing University Nanjing 210093China

The orientation between the backbone residues of proteins is defined based on the local configurations and the corresponding preferences are analyzed by *** is found that all the residue pairs have some specific preferences of *** statistical analysis is mainly concen-trated in the orientational distributions for two kinds of groupings of residues based on the hydrophobicity and secondary structural *** statistics for such two types of groupings shows different orienta-tional *** is found that for the former grouping the orientational preference is rather weak, while for the later a kind of strong orientational *** suggests that the formation of local structures and of secondary structures are highly related to the orientational preferences.

关键词：蛋白质主链定向参数选择残渣天然结构

Analysis of Dynamic Accumulation of Three Types of Glutenin Subunits and Their Content in Relation to Sedimentation Value in Common Wheat

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Agricultural Sciences in China 2006年第2期5卷 155-160页

作者： HAO jun-jie chen jun-ying chen Xin-jian CUI Dang-qun chenG Xi-yong College of Agronomy Henan Agricultural University Zhengzhou 450002 P.R.China Institute of Plant Protection Henan Academy of Agricultural Sciences Zhengzhou 450002 P.R. China

The biosynthetic time and accumulations of A-, B-, and C-type glutenin subunits in 7 winter wheat cultivars with different quality （strong, medium, weak gluten） were analyzed by SDS-PAGE. The results showed that no glutenin subunit was observed within 8 d after anthesis. Parts or all A-, B-, and C-type subunits appeared around day 12 in different cultivars. Other A-, B-, and C-type subunits appeared gradually. The accumulation of A-, B-, and C-type subunits fluctuated before maturity. The results of analysis of correlation between the ratios of A/T （total content of glutenin subunits）, A/C, AJ （B＋C）, （A＋B）/C, and （A＋B）/T and SDS-sedimentation value suggested that they were more significant. The negative correlation between the ratio of （B＋C）/T and SDS-sedimentation value was more significant, and the correlations between the ratio C/T and the SDS-sedimentation value were significantly negative.

关键词： wheat glutenin subunits dynamic accumulation quality

Study on Plant Regeneration of Wheat Mature Embryos Under Endosperm-Supported Culture

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Agricultural Sciences in China 2006年第8期5卷 572-578页

作者： chen jun-ying YUE Run-qing XU Hai-xian chen Xin-jian Department of Agronomy Henan Agricultural University Zhengzhou 450002 P.R.China

To reveal the suitability of using mature embryos as an explant source in wheat tissue culture, mature embryos from eight common wheat cultivars （Triticum aestivum L. cv.） were cultured with or without endosperm to test their efficiency of callus induction and plant regeneration. When embryos were cultured together with endosperm （endosperm-supported culture, ES）, the percentage of callus induction was significantly lower than that when embryos were cultured in the absence of endosperm （non-endosperm-supported culture, NES）. This pattern was evident in most genotypes, regardless of whether 2 or 8 mg L^-1 2,4-D was added in the NES culture. However, in ES culture, more induced calli were differentiated into distinct green spots and they further developed into plantlets. Thus, more plants were regenerated in ES culture than in the NES treatment. Most of the eight tested genotypes showed a significant difference in callus induction rate and plantlet regeneration in both ES and NES cultures. In addition, the enzymatic activity of oxalate oxidase in the callus of ES culture condition was obviously higher than that in the callus of NES culture condition, suggesting that the activity of oxalate oxidase may be a parameter for selection of calli with potential for plantlet regeneration. These results indicate that wheat mature embryos are valuable explants for highly efficient callus induction and plant regeneration, if proper treatment and medium are used.

关键词： mature wheat embryo tissue culture endosperm-supported plant regeneration oxalate oxidase activity

Fatigue Crack Propagation Law of Corroded Steel Box Girders in Long Span Bridges

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 201-227页

作者： ying Wang Longxiao Chao jun chen Songbai Jiang Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education School of Civil EngineeringSoutheast UniversityNanjing211189China Jiangsu Provincial Engineering Construction Standard Station Nanjing210036China

In order to investigate the fatigue performance of orthotropic anisotropic steel bridge decks,this study realizes the simulation of the welding process through elastic-plastic finite element theory,thermal-structural sequential coupling,and the birth-death element *** simulated welding residual stresses are introduced into the multiscale finite element model of the bridge as the initial ***,the study explores the impact of residual stress on crack propagation in the fatigue-vulnerable components of the corroded steel box *** results indicate that fatigue cracks at the weld toe of the top deck,the weld root of the top deck,and the opening of the transverse diaphragm will not propagate under the action of a standard vehicle ***,the inclusion of residual stress leads to the propagation of these *** considering residual stress,the fatigue crack propagation paths at the weld toe of the transverse diaphragm and the U-rib weld toe align with those observed in actual *** the absence of residual stress,the cracks at the toe of the transverse diaphragm with a 15%mass loss rate are categorized as type I ***,when residual stress is considered,these cracks become I-II composite *** stress significantly alters the cumulative energy release rate of the three ***,incorporating the influence of residual stress is essential when assessing the fatigue performance of corroded steel box girders in long-span bridges.

关键词： Residual stress crack propagation corroded steel box girder cumulative energy release rate

Development review and the prospect of oil shale in-situ catalysis conversion technology

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Petroleum Science 2024年第2期21卷 1385-1395页

作者： Li Wang chen-Hao Gao Rui-ying Xiong Xiao-jun Zhang Ji-Xiang Guo The Unconventional Oil and Gas Institute China University of Petroleum-BeijingBeijing102200China

As an unconventional resource, oil shale possesses abundant reserves and significant potential for industrial applications. The rational and efficient development of oil shale resources holds immense importance in reducing national energy demand. In-situ catalytic technology, characterized by its high efficiency, low pollution, and minimal energy consumption, represents a key direction for future oil shale development. This paper provides a comprehensive review of research progress in in-situ oil shale mining technology, oil shale pyrolysis catalysts, the pyrolysis mechanism of kerogen, and the compatibility of different heating processes and catalysts. Furthermore, the paper proposes future research directions and prospects for oil shale in-situ catalytic technology, including reservoir modification, highefficiency catalyst synthesis, injection processes, and high-efficiency heating technology. These insights serve as valuable technical references for the advancement of oil shale in-situ catalytic technology.

关键词： Oil shale In-situ catalytic technology Pyrolysis catalyst Kerogen pyrolysis mechanism

Aggregation of CeAlO_(3) inclusions in heavy ingot of a steel containing 0.007% aluminum

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Journal of Iron and Steel Research International 2024年第8期31卷 1960-1972页

作者： Qiu-yue Zhou jun-tao Ba Lun Zhang Wei chen ying Ren Li-feng Zhang School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

The distribution of inclusions at the bottom of a Ce-treated heavy steel ingot was detected and *** three-dimensional morphology and spatial distribution of CeAlOs clusters were characterized using the electrolytic extraction and Micro-CT detection.A model of inclusion collision to predict the aggregation of CeAlO_(3) inclusions in the ingot was established and validated by measured *** were mainly CeAlO_(3) and a small amount of Ce_(2)O_(2)S in the tundish after cerium *** collision and aggregation of inclusions led to the formation of large clusters in the ingot during the solidification *** slag entrainment inclusions,large CeAO_(3) clusters and small CeAlO_(3) particles were observed from the center to the edge of the ingot *** inclusions were mainly concentrated at the *** number density of inclusions larger than 200μm was 0.21 mm^(-3).The maximum diameter of CeA1O_(3) clusters was 1340μ*** the edge to the radial center and from the bottom to the top,the average diameter of inclusions gradually increased due to the longer solidification time of the ingot.

关键词： Inclusion Heavy ingot Cerium treatment Collision

Deep Guided Attention Network for Joint Denoising and Demosaicing in Real Image

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Chinese Journal of Electronics 2024年第1期33卷 303-312页

作者： Tao ZHANG ying FU jun ZHANG School of Computer Science and Technology Beijing Institute of Technology Advanced Reasearch Institute of Multidisciplinary Science Beijing Institute of Technology

Denoising(DN) and demosaicing(DM) are the first crucial stages in the image signal processing pipeline. Recently, researches pay more attention to solve DN and DM in a joint manner, which is an extremely undetermined inverse problem. Existing deep learning methods learn the desired prior on synthetic dataset, which limits the generalization of learned network to the real world data. Moreover, existing methods mainly focus on the raw data property of high green information sampling rate for DM, but occasionally exploit the high intensity and signalto-noise(SNR) of green channel. In this work, a deep guided attention network(DGAN) is presented for real image joint DN and DM(JDD), which considers both high SNR and high sampling rate of green information for DN and DM, respectively. To ease the training and fully exploit the data property of green channel, we first train DN and DM sub-networks sequentially and then learn them jointly, which can alleviate the error accumulation. Besides, in order to support the real image JDD, we collect paired raw clean RGB and noisy mosaic images to conduct a realistic dataset. The experimental results on real JDD dataset show the presented approach performs better than the state-of-the-art methods, in terms of both quantitative metrics and qualitative visualization.

关键词： Training Visualization Inverse problems Green products Noise reduction Pipelines Signal processing

Engineering a high-barrier d-f single-molecule magnet centered with hexagonal bipyramidal Dy(Ⅲ)unit

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Science China Chemistry 2024年第10期67卷 3291-3298页

作者： Wei Deng Chan-ying Yao Yan-Cong chen ying-Qian Zhou Shan-Nan Du jun-Liang Liu Ming-Liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistryInstitute of Green Chemistry and Molecular EngineeringGuangdong Basic Research Center of Excellence for Functional Molecular EngineeringSun Yat-sen UniversityGuangzhou 510006China

In the pursuit of high-performance single-molecule magnets(SMMs),incorporating intramolecular magnetic coupling emerges as a pivotal *** these,d-f SMMs have garnered significant attention due to their remarkable versatility,which lies in their ability to tune coordination environments and facilely substitute metal ***,achieving performance-centric d-f SMMs through the synergistic interplay between highly anisotropic f ions and d-f magnetic interactions remains a formidable *** mononuclear hexagonal bipyramidal(D_(6h))Dy^(Ⅲ)SMMs have been successfully isolated,the exploration of d-f SMMs featuring D_(6h)-lanthanide metal centers remains uncharted *** this study,we employed planar bipodal ligands in conjunction with“staple-like”axial phenoxide ligands to synthesize the first hexagonal bipyramidal d-f ***,this compound exhibits alternating-current magnetic susceptibilities peaking up to 68 K with an energy barrier surpassing 1,200 K,thus establishing a new benchmark within the heterometallic d-f SMM landscape inclusive of complexes with diamagnetic d metals and paramagnetic f ***,the ferromagnetic interaction at the d-f sites engenders oscillating relaxation times contingent on the magnetic field—a characteristic distinct from mononuclear *** findings shed light on a deliberate design approach for d-f SMMs,emphasizing the cooperative utilization of high-barrier lanthanide modules alongside d ions through magnetic *** synergy significantly enhances and diversifies the magnetic dynamics of these intriguing molecular systems.

关键词： single-molecule magnets magnetic coupling crystal engineering hexagonal bipyramid energy barrier

In situ modification of heavy oil catalyzed by nanosized metal-organic framework at mild temperature and its mechanism

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Chinese Journal of Chemical Engineering 2024年第3期67卷 166-173页

作者： Li Wang Ji-Xiang Guo Rui-ying Xiong chen-Hao Gao Xiao-jun Zhang Dan Luo The Unconventional Oil and Gas Institute China University of Petroleum-BeijingBeijing 102200China Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China

Two catalysts, nano-sized cobalt-metal-organic framework(Co-MOF) and nickel(Ni)-MOF, were successfully prepared by the modification method. Tetralin(C10H12) was used as the hydrogen donor for the catalytic cracking and hydrogenation modification study of the dehydrated crude oil from the Shengli Oilfield. The optimal reaction conditions were determined through orthogonal experiments, and the components of the crude oil and modified oil samples were analyzed. The results revealed that the nanoMOF catalysts were successfully prepared and exhibited high catalytic activity. They could catalyze the cracking of large molecules in heavy oil at mild temperatures(<300°C), leading to the decomposition of the hydrogen donor. When the mass fraction of the catalyst was 0.2%, the mass fraction of the hydrogen donor was 1%, and the reaction temperature was 280°C, the Ni-MOF showed the best catalytic viscosity reduction effect. It could reduce the viscosity of heavy oil at 50°C from 15761.9 m Pa.s to 1266.2 m Pa.s,with a viscosity reduction rate of 91.97%. The modification effect of Co-MOF was the next best, which could reduce the viscosity of heavy oil to 2500.1 m Pa.s with a viscosity reduction rate of 84.14%. Molecular dynamics simulations revealed a strong interaction force between the MOF surface and asphaltene molecules. In the process of heavy-oil catalytic hydrogenation, the nano-MOF catalyst exhibited high catalytic activity. On the one hand, the empty d orbitals outside the metal atoms in the catalyst could polarize the carbon atoms in the organic matter, accelerating the breaking of long chains. On the other hand, the metal atoms in the catalyst could bond with the carbon σ bonds, breaking the carbon-carbon bonds. This disrupted the structure of the recombined components in the crude oil, irreversibly reducing the viscosity of the heavy oil and improving its fluidity.

关键词： Nano-sized MOF Petroleum Viscosity reduction Catalyst Nanomaterials