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Taxuchin B,a New Chlorine-Containing Taxoid

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Chinese Chemical Letters 1997年第3期8卷 231-232页

作者： Fang, WS Fang, QC Liang, XT Lu, Y Wu, N zheng, qt CHINESE ACAD MED SCI INST MAT MEDBEIJING 100050PEOPLES R CHINA BEIJING UNION MED COLL BEIJING 100050PEOPLES R CHINA

A new taxoid, taxuchin B[1], has been isolated from twigs and needles of Taxus chinensis. It is the first chlorine-containing taxoid reported to date.

关键词： Zhang Chen

Asymmetric epoxidation of α,β-unsaturated ketones using α,α-diarylprolinols as catalysts

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Chinese Science Bulletin 2010年第17期55卷 1712-1722页

作者： zheng ChangWu ZHAO Gang Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

Asymmetric epoxidation of α,β-unsaturated ketones has been extensively studied and several important procedures have been developed in the last decade. This review addresses the most significant advances in asymmetric epoxidation of α,β-unsaturated ketones using proline-derived α,α-diarylprolinols as catalysts. Special attention has been paid to the enantioselective epoxidation of chalcones, α,β-unsaturated trifluoromethyl, trichloromethyl ketones and β,γ-unsaturated α-keto esters based on the reseach of our group.

关键词： β-不饱和酮不对称环氧化催化剂对映选择性三氟甲基脯氨酸查尔酮甲基酮

Revealing effect of aluminum alloying on work hardening and impact behaviors of low-density Fe-18Mn-1.3C-2Cr-(4,11)Al casting steel

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China Foundry 2022年第4期19卷 359-368页

作者： Zhi-bin zheng Hao-kun Yang A.P.Shatrava Wai-wah Lai Jun Long Kai-hong zheng Institute of New Materials Guangdong Academy of SciencesGuangdong Provincial Key Laboratory of Metal Toughening Technology and ApplicationGuangzhou 510650China Smart Manufacturing Division Hong Kong Productivity CouncilHong Kong 999077China Physicotechnological Institute of Metals and Alloys National Academy of SciencesKiev 03142Ukraine National Engineering Research Center of Powder Metallurgy of Titanium&Rare Metals Guangdong Provincial Iron Matrix Composite Engineering Research CenterGuangzhou 510650China

The present study designed two kinds of Fe-18Mn-1.3C-2Cr-(4,11)Al(wt.%)low-density *** and impact tests were carried out to evaluate the work hardening and impact toughness properties via aluminum(Al)alloying ***,microstructure evolution and fracture morphology were investigated by X-ray diffraction(XRD),a scanning electron microscope(SEM)equipped with electron backscatter diffraction(EBSD),a transmission electron microscope(TEM),and a stereo-optical microscope(OM).It is found that the Al addition obviously promotes the dislocation planar slipping,resulting in cleavage and brittle impact fracture in 11wt.%Al ***,the microband-induced plasticity(MBIP)mechanism is found in 4wt.%Al containing steel,introducing considerable work hardening capacity and impact toughness of 156.8±17.4 *** present study provides a direct illustration of the relationship between work hardening and impact toughness behaviors of these two low-density steels for potential application as impact-resistant components.

关键词： casting steel aluminum work hardening impact toughness tensile fractography impact fractography

Wind tunnel investigation of different engine layouts of a blended-wing-body transport

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Chinese Journal of Aeronautics 2023年第9期36卷 123-132页

作者： zheng CUI Guojun LAI Qifeng WANG Yu LIANG Yihua CAO School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China COMAC Beijing Aircraft Technology Research Institute Beijing 102211China

A 2%scale,cruising version of a 450-seat class Blended-Wing-Body(BWB)transport was tested in the China Aerodynamic Research and Development Center’s FL-262.4-by-2.4-meter subsonic wind *** focus of the wind tunnel test was to investigate the aerodynamic performance of the latest BWB transport design,which would also aid in choosing a final engine arrangement in the three most potential engine integration *** wind tunnel model can be tested with and without the nacelle and has three sets of different nacelle/tail integration *** Fluid Dynamics(CFD)simulations were performed in engine-aircraft integration design to find appropriate nacelle installing parameters of each *** comparison of CFD with experimental results shows good *** tunnel measurements indicate that the tail-mounted engine layout produces the minimum drag penalty,while the fuselage-mounted engine layout increases drag the *** pressure measurement illustrates the effect of nacelle integration on the wing-body surface pressure *** experimental and numerical research provides a reference for future BWB Propulsion-Airframe Integration(PAI)design.

关键词： PAI Aerodynamics BWB CFD Civil aviation Engine layout Transport aircraft Wind tunnels

Underwater four-quadrant dual-beam circumferential scanning laser fuze using nonlinear adaptive backscatter filter based on pauseable SAF-LMS algorithm

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Defence Technology（防务技术） 2024年第7期37卷 1-13页

作者： Guangbo Xu Bingting Zha Hailu Yuan Zhen zheng He Zhang Ministerial Key Laboratory of ZNDY Nanjing University of Science and TechnologyNanjing 210094China Science and Technology on Electromechanical Dynamic Control Laboratory Beijing 100081China Shanghai Radio Equipment Research Institute Shanghai 201109China

The phenomenon of a target echo peak overlapping with the backscattered echo peak significantly undermines the detection range and precision of underwater laser *** overcome this issue,we propose a four-quadrant dual-beam circumferential scanning laser fuze to distinguish various interference signals and provide more real-time data for the backscatter filtering *** enhances the algorithm loading capability of the *** order to address the problem of insufficient filtering capacity in existing linear backscatter filtering algorithms,we develop a nonlinear backscattering adaptive filter based on the spline adaptive filter least mean square(SAF-LMS)*** also designed an algorithm pause module to retain the original trend of the target echo peak,improving the time discrimination accuracy and anti-interference capability of the ***,experiments are conducted with varying signal-to-noise ratios of the original underwater target echo *** experimental results show that the average signal-to-noise ratio before and after filtering can be improved by more than31 d B,with an increase of up to 76%in extreme detection distance.

关键词： Laser fuze Underwater laser detection Backscatter adaptive filter Spline least mean square algorithm Nonlinear filtering algorithm

Three-dimensional meta-architecture with programmable mechanical properties

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International Journal of Smart and Nano Materials 2022年第1期13卷 152-165,I0009页

作者： Qiangqiang Zhang Jiaqi Dong Yantang Zhao and Yueyan zheng Key Laboratory of Mechanics on Disaster and Environment in Western China(Lanzhou University) The Ministry of Education of ChinaLanzhou730000P.R.China College of Civil Engineering and Mechanics Lanzhou UniversityLanzhou730000P.R.China

Artificial metamaterials have attracted widespread attention of research communities due to their anomalous physical properties compared to those of conventional *** this study,we designed a three-dimensional(3D)lightweight metaarchitecture consisting of 6-connected anti-chiral *** mechanical properties(***’s modulus,compression strength,and Poisson’s ratio)of the proposed meta-architecture could be programmed by adjusting a series of geometric parameters,as shown through numerical ***,an optically sensitive polymer-based 3D meta-architecture with 6-connected anti-chiral features was constructed by the stereolithography *** to the regulation of the negative Poisson’s ratio,3D meta-architecture achieved a greater ductility under compression than those of traditional truss structures while retaining a relatively high strength and low *** experiments validated the excellent tunability of the mechanical properties of the proposed 3D 6-connected antichiral *** results suggest the promising applications of this structure in lightweight aircraft,vibration isolation,and mechanical sensors.

关键词： Artificial metamaterials anomalous physical properties anti-chiral features ductile compressibility tunability on mechanical properties

Dynamic regulation of DNA methylation and histone modifications in response to abiotic stresses in plants

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Journal of Integrative Plant Biology 2022年第12期64卷 2252-2274页

作者： Yutong Liu Jie Wang Bao Liu zheng-Yi Xu Key Laboratory of Molecular Epigenetics of the Ministry of Education(MOE) Northeast Normal UniversityChangchun 130024China

DNA methylation and histone modification are evolutionarily conserved epigenetic modifications that are crucial for the expression regulation of abiotic stress-responsive genes in *** changes in gene expression levels can result from changes in DNA methylation and histone *** the last two decades,how epigenetic machinery regulates abiotic stress responses in plants has been extensively ***,based on recent publications,we review how DNA methylation and histone modifications impact gene expression regulation in response to abiotic stresses such as drought,abscisic acid,high salt,extreme temperature,nutrient deficiency or toxicity,and ultraviolet B *** also review the roles of epigenetic mechanisms in the formation of transgenerational stress *** posit that a better understanding of the epigenetic underpinnings of abiotic stress responses in plants may facilitate the design of more stress-resistant or-resilient crops,which is essential for coping with global warming and extreme environments.

关键词： abiotic stress DNA methylation histone modification transcriptional regulation

Mathematical Model for Electroslag Remelting Process

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Journal of Iron and Steel Research International 2007年第5期14卷 7-12,30页

作者： DONG Yan-wu JIANG Zhou-hua LI zheng-bang School of Materials and Metallurgy Northeastern University Shenyang 110004 Liaoning China Institute for Metallurgical Technology Central Iron and Steel Research Institute Beijing 100081 China

A mathematical model, including electromagnetic field equation, fluid flow equation, and temperature field equation, was established for the simulation of the electroslag remelting process. The distribution of temperature field was obtained by solving this model. The relationship between the local solidification time and the interdendritic spacing during the ingot solidification process was established, which has been regarded as a criterion for the evaluation of the quality of crystallization. For a crucible of 950 mm in diameter, the local solidification time is more than 1 h at the center of the ingot with the longest interdendritic spacing, whereas it is the shortest at the edge of the ingot according to the calculated results. The model can be used to understand the ESR process and to predict the ingot quality.

关键词： electroslag remelting mathematical model interdendritic spacing local solidification time

Segregation of Niobium During Electroslag Remelting Process

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Journal of Iron and Steel Research International 2009年第1期16卷 7-11页

作者： DONG Yan-wu JIANG Zhou-hua LI zheng-bang School of Materials and Metallurgy Northeastern University Shenyang 110004 Liaoning China Central Iron and Steel Research Institute Beijing 100081 China

Experiment was carried out after the process parameters were calculated by the model previously established. The relationship between interdendritic spacing and local solidification time （LST） mainly determined by process parameters was exposed. Furthermore, the extent of segregation was studied. The results indicate that LST and interdendritic spacing are the largest and the amount of Laves phase as a result of the niobium segregation is the highest in the center of the ingot, whereas the opposite results are obtained at the edge of ingot. The extent of element segregation and the amount of Laves phase can be reduced when appropriate parameters are used. Therefore, the duration of subsequent homogenization treatments for 718 is shortened and the alloy quality is improved.

关键词： electroslag remelting Inconel 718 segregation local solidification time interdendritic spacing