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Selectively reductive cleavage of the protected taxol side chain with sodium borohydride

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Chinese Journal of Chemistry 1996年第4期14卷 381-384页

作者： Yu, CZ Cheng, W Liu, zy CHINESE ACAD SCI SHANGHAI INST ORGAN CHEMSHANGHAI 200032PEOPLES R CHINA

During the course of our studies on the taxol chemistry, we have ever tried the reductive cleavage of the acetyl group at 20-C in compound 1a with the hydroxyl group assistance at 4-C by sodium borohydride. However, the major product 2a (27%) still had the acetyl group at 20-C and the signal for the 10-C proton at 6.61 ppm(s) was shifted to 6.31 ppm(d, J=3.79 Hz ). A new doublet signal at 3.62 ppm(d, J=3.80 Hz) appeared. These results with other spectral data indicated the 9-C carbonyl group of compound 1a was reduced to give 2a.

关键词： taxol cephalomannine baccatin III reductive cleavage side chain

Diterpenoid Alkaloids from Aconitum Nagarum var. Lasiandrum

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Chinese Chemical Letters 2000年第11期11卷 1005-1006页

作者： Dong, JY Li, zy Li, L Yunnan Univ Key Lab Fermentat Engn Ind Microbiol Kunming 650091 Peoples R China Kunming Inst Sci & Technol Dept Environm Engn Kunming 650093 Peoples R China Yunnan Univ Dept Chem Kunming 65009 Peoples R China

Two new diterpenoids, nagadine 1 and 14-benzoylsachaconitine 2 were isolated from the roots of Aconitum nagarum. Their structures were elucidated as 1 and 2 on the basis of spectral analysis.

关键词： Diterpenoid Alkaloids from Aconitum Nagarum var Lasiandrum EIMS Wang

Integral representation of M-band filters of Daubechies type

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Chinese Science Bulletin 1997年第10期42卷 803-807页

作者： Huang, DR Sun, QY Zhang, zy Center for Mathematical Sciences Zhejiang University Hangzhou China

FOR natural integers M≥2 and N≥1,M-band filter _N^MH(ξ)of Daubechies type is a trigono-metric polynomial _N^MH(ξ)with real coefficients such

关键词： filter vanishing moment integral representation.

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一道未定式极限习题的解法研究

科技风 2025年第1期 124-127页

作者：油俊彦菏泽学院数学与统计学院

极限是高等数学学习中的一个重点，是学生后续学习的重要基础与理论工具，但基于极限问题的形式多样性，因此它也是学生学习中的一个难点，尤其是未定式极限的求解方法更是灵活多样。■型未定式极限常用的方法主要有洛必达法则、等价无... 详细信息

极限是高等数学学习中的一个重点，是学生后续学习的重要基础与理论工具，但基于极限问题的形式多样性，因此它也是学生学习中的一个难点，尤其是未定式极限的求解方法更是灵活多样。■型未定式极限常用的方法主要有洛必达法则、等价无穷小的代换等，■型未定式极限常用的方法除了洛必达法则外，还要考虑使用重要极限、无穷大与无穷小的转化、重要结论等。本文针对一道■型的未定式极限习题，利用洛必达法则及其与多种形式的三角恒等变换的结合给出了六种解法，并对每一种解法进行了详细的分析。最后，总结在该题中得到的结论，旨在提高学生的计算能力和发散思维。

关键词：未定式极限洛必达法则三角恒等变换发散思维

Erosion Behaviour of TiNi Alloy Foils under Various Heat Treatments

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Journal of Materials Science & Technology 1996年第4期12卷 286-290页

作者： Liang, YN Wang, ZC Li, SZ Si, zy CHINESE ACAD SCI INST MET RESSHENYANG 110015PEOPLES R CHINA

The erosion behaviour of TiNi alloy foils (Ni: 50.5 at pct, thickness: 70-90 mu m) under various heat treatments has been studied with two different tests: sand-blasting erosion (SBE) with impingement angle of 30 degrees and slurry erosion (SE). The erosion resistance of the foils aged at 400-450 degrees C/30 min is the best in all tests. The quenched foil is also good in the SBE test, but not so good in the SE test. The slurry-erosion resistance of the aged foils is better than that of L214 with high hardness. All the foils exhibit much better erosion resistance than 18Cr-8Ni stainless steel in the tests.

关键词： Metal foil

Effect of anisotropic characteristics on the mechanical behavior of asphalt concrete overlay

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Frontiers of Structural and Civil Engineering 2019年第1期13卷 110-122页

作者： Lingyun you Zhanping you Kezhen YAN Department of Civil and Environmental Engineering Michigan Technological UniversityHoughtonMI 49931USA College of Civil Engineering Hunan UniversityChangsha 410082China

Asphalt concrete (AC)overlays placed over old asphalt pavement have become an alternative to repairing and reinforcing *** strength contributed by the AC overlay is strongly influenced by the anisotropic properties of the pavement *** study was conducted to analyze the influence of anisotropy,modulus gradient properties,and the condition of the AC overlay and old pavement contact plane on the mechanical behaviors of AC overlays,as well as to quantify the influence of the degree of anisotropy on the mechanical behaviors of AC overlay by a sensitivity analysis (SA).The mechanical behaviors of the AC overlay were numerically obtained using the three- dimensional finite element method with the aid of ABAQUS,a commercial *** in the AC overlay's modulus as a function of temperature as well as the contact state between the AC overlay and AC layer were considered. The SA is based on standardized regression coefficients *** the mechanical behavior in terms of surface deflection,stress,and strain of the anisotropy model against those corresponding to the isotropic model under static loads show that the anisotropic properties had greater effects on the mechanical behavior of the AC *** addition,the maximum shear stress in the AC overlay was the most significant output parameter affected by the degree of anisotropy. Therefore,future research concerning the reinforcement and repair of pavements should consider the anisotropic properties of the pavement materials.

关键词： asphalt concrete overlay anisotropy temperature gradients modulus gradients finite element simulation sensitivity analysis

Mission-driven autonomous perception and fusion based on UAV swarm

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Chinese Journal of Aeronautics 2020年第11期33卷 2831-2834页

作者： you HE Research Institute of Information Fusion Naval Aviation UniversityYantai 264001China

Distributed autonomous situational awareness is one of the most important foundation for Unmanned Aerial Vehicle(UAV)swarm to implement various *** the application environment being usually characterized by strong confrontation,high dynamics,and deep uncertainty,the distributed situational awareness system based on UAV swarm needs to be driven by the mission requirements,while each node in the network can autonomously avoid collisions and perform detection mission through limited resource sharing as well as complementarity of respective *** efficiently solving the problems of self-avoidance,autonomous flocking and splitting,joint estimation and control,etc.,perception data from multi-platform multi-source should be extracted and fused reasonably,to generate refined,tailored target information and provide reliable support for decision-making.

关键词： Autonomous perception Consensus Distributed information fusion Situation awareness State estimation Swarm Unmanned aerial vehicle

LEGENDRE SERIES SOLUTIONS FOR TIME-VARIATION DYNAMICS

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Acta Mechanica Solida Sinica 2000年第1期13卷 60-66页

作者： Cao, zy Zou, GP Tang, SG Tongji Univ Dept Engn Mech & Technol MOE Key Lab Solid Mech Shanghai 200092 Peoples R China

In this topic, a new. approach to the analysis of time-variation dynamics is proposed by use of Legendre series expansion and Legendre integral operator matrix. The theoretical basis for effective solution of time-var... 详细信息

关键词： time-variation dynamics Legendre series state space equation integral operator matrix

Fire resistance evaluation through synthetic fire tests and generative adversarial networks

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 587-614页

作者： Aybike Özyüksel Çiftçioğlu M.Z.Naser Department of Civil Engineering Manisa Celal Bayar University45140Türkiye School of Civil&Environmental Engineering and Earth Sciences(SCEEES) Clemson UniversityClemsonSC 29631USA Artificial Intelligence Research Institute for Science and Engineering(AIRISE) Clemson UniversityClemsonSC 29631USA

This paper introduces a machine learning approach to address the challenge of limited data resulting from costly and time-consuming fire experiments by enlarging small fire test data sets and predicting the fire resistance of reinforced concrete *** approach begins by creating deep learning models,namely generative adversarial networks and variational autoencoders,to learn the spatial distribution of real fire *** then use these models to generate synthetic tabular samples that closely resemble realistic fire resistance values for reinforced concrete *** generated data are employed to train state-of-the-art machine learning techniques,including Extreme Gradient Boost,Light Gradient Boosting Machine,Categorical Boosting Algorithm,Support Vector Regression,Random Forest,Decision Tree,Multiple Linear Regression,Polynomial Regression,Support Vector Machine,Kernel Support Vector Machine,Naive Bayes,and K-Nearest Neighbors,which can predict the fire resistance of the columns through regression and *** learning analyses achieved highly accurate predictions of fire resistance values,outperforming traditional models that relied solely on limited experimental *** study highlights the potential for using machine learning and deep learning analyses to revolutionize the field of structural engineering by improving the accuracy and efficiency of fire resistance evaluations while reducing the reliance on costly and time-consuming experiments.

关键词： deep learning fire resistance generative adversarial networks machine learning