Crack tip behavior and crack-propagation in ductile materials

Dilatational plastic equations, which can include the effects of ductile damage, are derived based on the equivalency in expressions for dissipated plastic work. Void damage developed internally at the large-strain stage is represented by an effective continuum being strain-softened and plastically dilated. Accumulation of this local damage leads to progressive failure in materials. With regard to this microstructural background, the constitutive parameters included for characterizing material behaviour have the sense of internal variables. They are not able to be determined explicitly by macroscopic testing but rather through computer simulation of experimental curves and data. Application of this constitutive model to mode-I cracking examples demonstrates that a huge strain concentration accompanied by a substantial drop of stress does occur near the crack tip. Eventually, crack propagation is simulated by using finite elements in computations. Two numerical examples show good accordance with experimental data. The whole procedure of study serves as a justification of the constitutive formulation proposed in the text.

Nonlinear Fluid Damping In Structure-Wake Oscillators In Modeling Vortex-Induced Vibrations

A Nonlinear Fluid Damping (NFD) in the form of the square-velocity is applied in the response analysis of Vortex-induced Vibrations (VIV). Its nonlinear hydrodynamic effects oil the coupled wake and structure oscillators are investigated. A comparison between the coupled systems with the linear and nonlinear fluid dampings and experiments shows that the NFD model can well describe response characteristics, such as the amplification of body displacement at lock-in and frequency lock-ill, both at high and low mass ratios. Particularly, the predicted peak amplitude of the body in the Griffin plot is ill good agreement with experimental data and empirical equation, indicating the significant effect of the NFD on the structure motion.

High-energy ion emission from cooled deuterium clusters in 20 TW laser fields

High-energy ion emission from intense-ultrashort (30fs) laser-pulse- cooled deuterium-cluster (80K) interaction is measured. The deuterium ions have an average energy 20keV, which greatly exceeds Zweiback's expectation [Phys. Rev. Lett. 84 (2000) 2634]. These fast deuterium ions can be used to drive fusion and have a broad prospect.

反式和顺式-1，2-二氰-（4-乙基苯）乙烯结构的谱学分析

合成了2种新型的可溶性四氮杂卟啉中间体：反式-1，2二氰-（4-乙基苯）乙烯和顺式-1，2-二氰（4-乙基苯）乙烯。通过UV-Vis，FFIR，GC／MS，^1H NMR等方法对这2种化合物的结构进行了表征，给出了它们完整的结构信息。分析比较了顺、反异构体结构上的差异，分析两者的紫外-可见光谱（UV-Vis）、红外光谱（FTIR）和核磁共振光谱（^1H NMR）谱图的差异及其产生原因。

芳香植物及其化学成份（英文版）

芳香植物的利用过去只局限于传统的少数品种，主要是对植物的化学成分所知甚少，本书作者对国内近500种芳香植物进行了考察，收集样品进行化学分析，工作量大，难度高。由于采用了GC/MS/DS近代精油研究先进方法，数据结果可靠，是国内该类工作中最出色、最系统的一本专著。同类的著作在国外亦不多见。此书用英文出版，对国外香料植物的研究应用亦有深远的影响。本书资料完整、科学性强，有创新，属国际先进水平。

芳香植物化及其学成分

芳香植物的利用过去只局限于传统的少数品种，主要是对植物的化学成分所知甚少，本书作者对国内近500种芳香植物进行了考察，收集样品进行化学分析，工作量大，难度高。由于采用了GC/MS/DS近代精油研究先进方法，数据结果可靠，是国内该类工作中最出色、最系统的一本专著。同类的著作在国外亦不多见。此书用英文出版，对国外香料植物的研究应用亦有深远的影响。本书资料完整、科学性强，有创新，属国际先进水平。