There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Much of the existing literature on dielectric elastomers has focused on quasi-static deformation. However, in some potential applications, the elastomer deforms at high frequencies and undergoes nonlinear oscillation. While nonlinear oscillation has been studied in many areas of science and engineering, we are unaware of any theoretical analysis of nonlinear oscillation of dielectric elastomers. This paper reports a theoretical study of the dynamic behavior of a dielectric elastomer balloon subject to a combination of pressure and voltage. When the pressure and voltage are static, the balloon may reach a state of equilibrium. We determine the stability of the state of equilibrium, and calculate the natural frequency of the small-amplitude oscillationaroundthestateof equilibrium.Wefocus ontheparametricresponsesof thedielectric elastomerballoon.Whenthe voltage is sinusoidal, the balloon resonates at multiple frequencies of excitation, giving rise to superharmonic, harmonic and subharmonic responses. When the frequency of excitation varies continuously, the oscillating amplitude of the balloon may jump, exhibitinghysteresis. c � 2010 Society of Chemical Industry

/pdf/nonlinear-oscillation-of-a-dielectric-elastomer-balloon-1vrl1ujry9.pdf

Nonlinear oscillation of a dielectric elastomer balloon

A thin, brittle layer bonded between tougher substrates is susceptible to cracking under residual and applied stresses. Such a crack initiates from an equi-axed flaw, confined by the substrates, tunneling in the brittle layer. Although tunneling is a three-dimensional process, the energy release rate at the front of a steady-state tunnel can be computed using plane strain fields. Several technically important problems are analyzed, including tunnels in adhesive joints, shear fracture, and kinked tunnels in a reaction product layer. The concept is finally applied to microcracking in brittle matrix composites caused by thermal expansion mismatch.

Tunneling Cracks in Constrained Layers

A gel is an aggregate of polymers and solvent molecules. The polymers crosslink into a three-dimensional network by strong chemical bonds and enable the gel to retain its shape after a large deformation. The solvent molecules, however, interact among themselves and with the network by weak physical bonds and enable the gel to be a conduit of mass transport. The time-dependent concurrent process of large deformation and mass transport is studied by developing a finite element method. We combine the kinematics of large deformation, the conservation of the solvent molecules, the conditions of local equilibrium, and the kinetics of migration to evolve simultaneously two fields: the displacement of the network and the chemical potential of the solvent. The finite element method is demonstrated by analyzing several phenomena, such as swelling, draining and buckling. This work builds a platform to study diverse phenomena in gels with spatial and temporal complexity.

/pdf/a-finite-element-method-for-transient-analysis-of-concurrent-dmtvimd6a7.pdf

A finite element method for transient analysis of concurrent large deformation and mass transport in gels

https://imechanica.org/files/propagation%20of%20instability%20in%20dielectric%20ealstomers.pdf

Propagation of instability in dielectric elastomers

Although soft devices (grippers, actuators, and elementary robots) are rapidly becoming an integral part of the broad field of robotics, autonomy for completely soft devices has only begun to be developed. Adaptation of conventional systems of control to soft devices requires hard valves and electronic controls. This paper describes completely soft pneumatic digital logic gates having a physical scale appropriate for use with current (macroscopic) soft actuators. Each digital logic gate utilizes a single bistable valve-the pneumatic equivalent of a Schmitt trigger-which relies on the snap-through instability of a hemispherical membrane to kink internal tubes and operates with binary high/low input and output pressures. Soft, pneumatic NOT, AND, and OR digital logic gates-which generate known pneumatic outputs as a function of one, or multiple, pneumatic inputs-allow fabrication of digital logic circuits for a set-reset latch, two-bit shift register, leading-edge detector, digital-to-analog converter (DAC), and toggle switch. The DAC and toggle switch, in turn, can control and power a soft actuator (demonstrated using a pneu-net gripper). These macroscale soft digital logic gates are scalable to high volumes of airflow, do not consume power at steady state, and can be reconfigured to achieve multiple functionalities from a single design (including configurations that receive inputs from the environment and from human users). This work represents a step toward a strategy to develop autonomous control-one not involving an electronic interface or hard components-for soft devices.

https://www.pnas.org/content/pnas/116/16/7750.full.pdf

Zhigang Suo

Papers

Nonlinear oscillation of a dielectric elastomer balloon

Tunneling Cracks in Constrained Layers

A finite element method for transient analysis of concurrent large deformation and mass transport in gels

Propagation of instability in dielectric elastomers

Digital Logic for Soft Devices