折叠,形态,结构:综述折叠理论在建筑中的应用

折叠、形态、结构分别对应了理论、方法、技术三个层面。本文首先对折叠概念进行解析,用折纸这项人们熟知的折叠艺术作为引导,依次对折叠理论在建筑学中的分支及发展历程,折叠方法在建筑形态中的应用以及折叠技术和折叠形态在结构体系上的应用三方面进行简要综述。

仿生层级薄壁方管耐撞性数值分析及优化

为提高传统薄壁方管的吸能效率,受甲虫翅鞘微观小梁结构启发,提出了一种仿生层级薄壁方管(Bionic Hierarchical thin-walled Square Tube,BHST)。基于超折叠单元理论,建立了BHST平均压溃力理论模型。通过非线性有限元法分析BHST与传统多胞薄壁方管轴向吸能特性,研究了结构参数对BHST4-2结构耐撞性的影响。结果表明,理论预测与数值模拟结果吻合,相对误差均在7%以内。BHST具有优异的耐撞性。与二阶方管边长相比,壁厚对BHST4-2结构的耐撞性影响更显著。采用径向基函数(Radial Basis Function,RBF)模型和遗传算法对BHST4-2结构进行了多目标优化,得到了结构最优参数。研究结果为设计具有优异吸能特性的薄壁方管提供了新思路。

Compacton, Peakon, and Foldon Structures in the （2＋1）-DimensionalNizhnik-Novikov-Veselov Equation

By the use of the extended homogenous balance method,the B(?)cklund transformation for a (2+1)- dimensional integrable model,the(2+1)-dimensional Nizhnik-Novikov-Veselov (NNV) equation,is obtained,and then the NNV equation is transformed into three equations of linear,bilinear,and tri-linear forms,respectively.From the above three equations,a rather general variable separation solution of the model is obtained.Three novel class localized structures of the model are founded by the entrance of two variable-separated arbitrary functions.

Quantum theory on protein folding

The conformational change of biological macromolecule is investigated from the point of quantum transition.A quantum theory on protein folding is proposed.Compared with other dynamical variables such as mobile electrons,chemical bonds and stretching-bending vibrations the molecular torsion has the lowest energy and can be looked as the slow variable of the system.Simultaneously,from the multi-minima property of torsion potential the local conformational states are well defined.Following the idea that the slow variables slave the fast ones and using the nonadiabaticity operator method we deduce the Hamiltonian describing conformational change.It is shown that the influence of fast variables on the macromolecule can fully be taken into account through a phase transformation of slow variable wave function.Starting from the conformation-transition Hamiltonian the nonradiative matrix element was calculated and a general formulas for protein folding rate was deduced.The analytical form of the formula was utilized to study the temperature dependence of protein folding rate and the curious non-Arrhenius temperature relation was interpreted.By using temperature dependence data the multi-torsion correlation was studied.The decoherence time of quantum torsion state is estimated.The proposed folding rate formula gives a unifying approach for the study of a large class problems of biological conformational change.

EMBEDDINGS OF SIMPLE TWO-FOLD BALANCED INCOMPLETE BLOCK DESIGNS WITH BLOCK SIZE FOUR

The necessary and sufficient conditions for the existence of simple incomplete block design （v, ω; 4, 2）-IPBDs are determined. As a consequence, the necessary and sufficient conditions for the embeddings of simple two-fold balanced incomplete block designs with block size 4 are also determined.

Failure modeling of folded dielectric elastomer actuator

When subjected to voltage,the dielectric elastomer membrane reduces its thickness and expands its area under the resulting compressive force.This characteristic enables the dielectric elastomer actuators of different structures to be designed and fabricated.By employing the thermodynamic theory and research method proposed by Suo et al.,an equilibrium equation of folded dielectric elastomer actuator with two generalized coordinates is established.The governing equations of failure models involving electromechanical instability,zero electric field,electrical breakdown,loss of tension,and rupture by stretch are also derived.The allowable areas of folded dielectric elastomer actuators are described.These results could provide a powerful guidance to the design and performance evaluation of the dielectric elastomer actuators.