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Exact Location of Linear B-cell Epitopes of VP3 Protein of Goose Parvovirus

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畜牧兽医学报 2011年第B12期42卷 34-39页

作者： GUO Lu JU Huan-yu YU Tian-fei JING zhi-qiang ma bo WANG Jun-wei （College of Veterinary Medicine Northeast Agricultural University Harbin 150030 China）

Four monoclonal antibodies (mabs) against Goose Parvovirus (GPV) VP3 protein already available were used to precisely locate linear B-cell epitopes in VP3 of GPV. The epitopes, recognized by four mabs, had already been identified at low levels of resolution. Complementary oligonucleotides encoding ten amino acid fragments, with five amino acid overlaps were designed with suitable sticky ends for recombination with pET-32a and subsequent expression as small-fragment fusion proteins. Antigenicity of specific oligopeptides was determined by Western blotting with the mabs. Using the same methods, amino acids were deleted one by one from the peptides of interest, enabling the two epitopes to be precisely located at amino acids 430-435 (-DRIMNP-) and 643-647 (-VFIKN-).

关键词： VP3基因鹅细小病毒 B细胞表位 VP3蛋白抗原表位线性单克隆抗体位置

Catalysis by subsurface metal atoms in Al(001) through electron transfer

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National Science Review 2024年第4期11卷 12-13页

作者： bo Sun Ding ma Beijing National Laboratory for Molecular Science New Cornerstone Science Laboratory College of Chemistry and Molecular Engineering Peking University

Heterogeneous catalysis plays a crucial role in the chemical industry, which has evolved from the investigation of chemisorption to an electronic structure[1]. Diverse strategies, such as alloying,doping, and confining, have been applied to enhance the catalytic properties of active sites through electronic modulation. The electron transfer between active sites and substrates profoundly influences catalytic activity [2].

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Access to High-Molecular-Weight Polyethylenes through High Temperature Ethylene Polymerization Catalysed by Ethylene-Bridged ansa-(3-R-Cyclopentadienyl)(Fluorenyl) Zirconocene Complexes

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Chinese Journal of Polymer Science 2024年第1期42卷 42-51,I0007页

作者： bo Li Haiyan ma Jiling Huang Shanghai Key Laboratory of Functional materials Chemistry and Laboratory of Organometallic Chemistry School of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

A series of C1-symmetric ethylene-bridged ansa-(3-R-cyclopentadienyl)(fluorenyl) metallocene complexes(Zr: 1-5;Hf: 6) have been synthesized, characterized and investigated as catalyst precursors for the high temperature ethylene polymerization. Using methylaluminoxane(maO) as the cocatalyst, zirconium complexes 1-5 bearing a bulky substituent on the 3-position of the cyclopendienyl ring showed high catalytic activities up to 1.48×10^(7) g PE·mol_(Zr)^(-1)·h^(-1) toward the polymerization of ethylene and afforded polyethylenes with high molecular weights(1.49×10^(5)-6.31×10^(5) g/mol), meanwhile exhibting great thermal stability at high temperatures up to 120 ℃ together with a long catalytic life time up to 2 h. By adopting low Al/Zr ratios, such as 125, polyethylenes with ultra high molecular weights up to 2.86×106 g/mol were obtained. It is worthy of noting that zirconium complexes 1-4 bearing a substituent with an aryl pendant showed temperature-dependent activities, which increased rapidly with the increase of polymerization temperature, thus weak interaction of the pendent aryl group with the cationic active center is proposed to account for the very low activities displayed at low temperatures. In contrast to zirconocene complexes 1-5, hafnocene complex 6 only displayed very low catalytic activities toward the polymerization of ethylene and afforded polyethylenes with molecular weights ten times smaller than those obtained by zirconocene complexes 1-5. Zirconocene complexes 1-5 were also able to catalyse the polymerization of propylene at high temperatures, but only afforded waxes with low molecular weights.

关键词： ansa-Metallocene Ethylene Propylene Polymerization High temperature

Catalytic recycling of polyesters via a binuclear catalyst

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Science China Chemistry 2024年第2期67卷 426-427页

作者： bo Sun Ding ma Beijing National Laboratory for Molecular Science New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

Plastics play a crucial role in modern society life. While the increasing use of plastics and rapid accumulation of plastic waste in nature environment have caused severe environmental crisis and the waste of carbon resources. Catalytic upcycling is a promising approach to transform plastic waste into high value-added chemicals to achieve a sustainable circular economy.

关键词： Catalytic polyester catalyst

Achieving strength-ductility synergy in novel paramagnetic Fe-based medium-entropy alloys through deep cryogenic deformation

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Rare Metals 2024年第9期43卷 4493-4507页

作者： Hu-Wen ma Yan-Chun Zhao Li Feng Tian-Zeng Liu zhi-Qi Yu bo Jin Wang-Chun Duan Peter K.Liaw Dong ma State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals Lanzhou University of TechnologyLanzhou 730050China Wenzhou Pump and Valve Engineering Research Institute Lanzhou University of TechnologyWenzhou 325105China Iron and Steel Research Institute Jiuquan Iron and Steel CorporationJiayuguan 735100China Lanzhou Resources and Environment Voc-Tech University Lanzhou 730123China Department of materials Science and Engineering The University of TennesseeKnoxvilleTN 37996-2200USA Neutron Science Center Songshan Lake Materials LaboratoryDongguan 523808China

Cryogenic pre-deformation treatment has been widely used to effectively improve the comprehensive mechanical properties of steels and novel ***,the dislocation evolution and phase transformation induced by different degrees of deep cryogenic deformation are not yet fully *** this study,the effects of multiple cryogenic pre-treatments on the mechanical properties and deformation mechanisms of a paramagnetic Fe_(63.3)Mn_(14-)Si_(9.1)Cr_(9.8)C_(3.8)medium-entropy alloy(MEA)were investigated,leading to the discovery of a pretreated MEA that exhibits exceptional mechanical properties,including a fracture strength of 3.0 GPa,plastic strain of 26.1%and work-hardening index of *** addition,X-ray diffraction(XRD)and transmission electron microscopy(TEM)analyses revealed that multiple cryogenic pre-deformation treatments significantly increased the dislocation density of the MEA(from 9×10^(15)to 4×10^(16)m^(-2)after three pretreatments),along with a transition in the dislocation type from predominantly edge dislocations to mixed dislocations(including screw-and edge-type dislocations).Notably,this pretreated MEA retained its paramagnetic properties(μ_(r)mately four(i.e.,from 9.7 to2.6 m J·m^(-2)),thereby activating the synergistic effects of transformation-induced plasticity,twinning-induced plasticity and dislocation strengthening *** synergistic effects lead to simultaneous strength and ductility enhancement of the MEA.

关键词： Deep cryogenic transformation Iron-based medium-entropy alloys Dislocation evolution Phase transformation Stacking fault energy

Deciphering and integrating invariants for neural operator learning with various physical mechanisms

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National Science Review 2024年第4期11卷 111-122页

作者： Rui Zhang Qi Meng zhi-Ming ma Academy of mathematics and Systems Science Chinese Academy of Sciences(CAS) Microsoft Research

Neural operators have been explored as surrogate models for simulating physical systems to overcome the limitations of traditional partial differential equation(PDE) solvers. However, most existing operator learning methods assume that the data originate from a single physical mechanism, limiting their applicability and performance in more realistic scenarios. To this end, we propose the physical invariant attention neural operator(PIANO) to decipher and integrate the physical invariants for operator learning from the PDE series with various physical mechanisms. PIANO employs self-supervised learning to extract physical knowledge and attention mechanisms to integrate them into dynamic convolutional *** to existing techniques, PIANO can reduce the relative error by 13.6%–82.2% on PDE forecasting tasks across varying coefficients, forces or boundary conditions. Additionally, varied downstream tasks reveal that the PI embeddings deciphered by PIANO align well with the underlying invariants in the PDE systems, verifying the physical significance of PIANO.

关键词： neural operator PDE solver contrastive learning physical invariants

Development of a convolutional neural network based geomechanical upscaling technique for heterogeneous geological reservoir

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2111-2125页

作者： zhiwei ma Xiaoyan Ou bo Zhang Earth and Environmental Sciences Division Los Alamos National LaboratoryLos AlamosUSA Civil and Environmental Engineering University of AlbertaEdmontonCanada

Geomechanical assessment using coupled reservoir-geomechanical simulation is becoming increasingly important for analyzing the potential geomechanical risks in subsurface geological ***,a robust and efficient geomechanical upscaling technique for heterogeneous geological reservoirs is lacking to advance the applications of three-dimensional(3D)reservoir-scale geomechanical simulation considering detailed geological ***,we develop convolutional neural network(CNN)proxies that reproduce the anisotropic nonlinear geomechanical response caused by lithological heterogeneity,and compute upscaled geomechanical properties from CNN *** CNN proxies are trained using a large dataset of randomly generated spatially correlated sand-shale realizations as inputs and simulation results of their macroscopic geomechanical response as *** trained CNN models can provide the upscaled shear strength(R^(2)>0.949),stress-strain behavior(R^(2)>0.925),and volumetric strain changes(R^(2)>0.958)that highly agree with the numerical simulation results while saving over two orders of magnitude of computational *** is a major advantage in computing the upscaled geomechanical properties directly from geological realizations without the need to perform local numerical simulations to obtain the geomechanical *** proposed CNN proxybased upscaling technique has the ability to(1)bridge the gap between the fine-scale geocellular models considering geological uncertainties and computationally efficient geomechanical models used to assess the geomechanical risks of large-scale subsurface development,and(2)improve the efficiency of numerical upscaling techniques that rely on local numerical simulations,leading to significantly increased computational time for uncertainty quantification using numerous geological realizations.

关键词： Upscaling Lithological heterogeneity Convolutional neural network(CNN) Anisotropic shear strength Nonlinear stressestrain behavior

Realizing high initial Coulombic efficiency in manganese-based layered oxide cathodes for sodium-ion batteries via P2/O'3 biphasic structure optimization

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Rare Metals 2024年第5期43卷 2093-2102页

作者： bo Peng Zi-Hao Zhou Ping Xuan Jie Xu Lian-bo ma School of materials Science and Engineering Anhui University ofTechnologyMa'anshan 243002China Anhui Product Quality Supervision&Inspection Research Institute Hefei 230051China

Mn-based layered oxides are among the most promising cathode materials for sodium-ion batteries owing to the advantages of abundance,environmenta friendliness,low cost and high specific capacity.P2 and O'3 are two representative structures of Mn-based layered ***,the P2 structure containing insufficien Na generally exhibits low initial charge capacity,while O'3structure with sufficient Na delivers high initial charge capacity but poor cycle *** study prepared a multitude of Na_(x)MnO_(2)(x=0.7,0.8,0.9)cathode materials with varying P2/O'3 ratios and further investigated their electrochemical *** optimized Na_(0.8)MnO_(2) comprising 69.9 wt%O'3 and 30.1 wt%P2 phase,exhibited relatively balanced specific capacity,Coulombic efficiency and cycle ***,it achieved a high specific capacity of 128.9 mah·g^(-1) with an initia Coulombic efficiency of 98.2%in half-cell configuration The Na_(0.8)MnO_(2)//hard carbon full cell also achieved a high specific capacity of 126.7 mah·g^(-1) with an initia Coulombic efficiency of 98.9%.Moreover,the capacity fading mechanism was revealed by combining in-situ and ex-situ X-ray *** findings of this study provide theoretical guidance for further modification design of Mnbased layered cathodes.

关键词： Sodium-ion batteries Cathode materials Mn-based layered oxides P2/0'3 composites

The Multi-parameter Test of Gravitational Wave Dispersion with Principal Component Analysis

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Research in Astronomy and Astrophysics 2024年第5期24卷 140-150页

作者： zhi-Chu ma Rui Niu Wen Zhao CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

In this work, we consider a conventional test of gravitational wave(GW) propagation which is based on the phenomenological parameterized dispersion relation to describe potential departures from General Relativity(GR)along the propagation of GWs. But different from tests conventionally performed previously, we vary multiple deformation coefficients simultaneously and employ the principal component analysis(PCA) method to remedy the strong degeneracy among deformation coefficients and obtain informative posteriors. The dominant PCA components can be better measured and constrained, and thus are expected to be more sensitive to potential departures from the waveform model. Using this method we analyze ten selected events and get the result that the combined posteriors of the dominant PCA parameters are consistent with GR within 99.7% credible intervals. The standard deviation of the first dominant PCA parameter is three times smaller than that of the original dispersion parameter of the leading order. However, the multi-parameter test with PCA is more sensitive to not only potential deviations from GR but also systematic errors of waveform models. The difference in results obtained by using different waveform templates hints that the demands of waveform accuracy are higher to perform the multiparameter test with PCA. Whereas, it cannot be strictly proven that the deviation is indeed and only induced by systematic errors. It requires more thorough research in the future to exclude other possible reasons in parameter estimation and data processing.

关键词： gravitational waves-gravitation-black hole physics