송민호 교수

It has been shown that many proteins, when converted into partially unfolded structures, interact strongly with a lipid bilayer. SecA protein of Escherichia coli is an unusual water-soluble protein which, in the native form, can readily penetrate the membrane and lipid bilayer. In order to see whether the native SecA exhibits partially unfolded characteristics, the stability and solvent accessibility of SecA were studied using various spectroscopic and hydrogen-exchange methods. The results are

Synthetic capsules in which a thin membrane encloses some biological or chemical ingredients are used in diverse industrial and biomedical applications. In extreme flow environments, the hydrodynamic loading acting on the membrane of the capsule may cause large deformation and structural failure. Although previous experimental studies have focused on the rheological behavior of capsules immersed in different types of flow, the mechanical characteristics of capsules under high shear rate and thei

We experimentally investigate the transport of liquid by a toroidal bubble that rises vertically and penetrates a horizontal interface between two immiscible liquids. Experiments are conducted with various strengths of vortex circulation in the bubble, and with different liquid densities and viscosities. In contrast to a spherical bubble, a rising toroidal bubble carries a great amount of the lower liquid by virtue of the self-induction of circulating flow. The lower liquid is entrained by the t

Abstract

Motivated by drag-based propulsion of crinoids, the shape reconfiguration of a feather-like elastic structure under both steady and unsteady translational motions is investigated. The simplified elastic structure consists of a centre rod to which numerous side flaps are attached by elastic hinges. These side flaps fold in only one direction to realize a dramatic reduction in the area of the structure during the recovery stroke. Compared with experimental measurements, analytical methods develope

Abstract

The dynamic behaviors of an interface between two immiscible fluids, which are deformed by a vortex ring impinging normally onto the interface, are experimentally investigated. By varying the strength and size of the vortex ring generated by a piston-cylinder apparatus, several deformation modes of the immiscible interface are identified based on the deforming and rebounding processes and instability of the interface. At a given penetration depth, the profiles of the interfacial deformation shap

We measured ESR of phosphorous-doped silicon with a low concentration of P, n, at high magnetic fields and low temperatures to investigate the states of nuclear spin. A sample with n = 6.52 × 1016 /cm3 was studied at 2.85 T (80 GHz) from 30 K to 2.3 K by field-modulating cw-ESR for a fixed 0 dB power. As the temperature was lowered, the out-of-phase signal appeared around 18 K, reached at a maximum intensity at 13 K, and disappeared around 6 K. The out-of-phase signal is referred to the field mo

Motivated by the propulsion of animals using articulated bodies, this study experimentally investigates the deformation and torque generation of a multi-segmented structure undergoing flapping motion. The segmented structure consists of multiple rigid segments connected in a line through elastic sheets functioning as elastic hinges. To enhance the asymmetry in the deflection of the segmented structure between the power and recovery strokes, the elastic hinges are designed to bend only one way fr

Spin dynamics of shallow-trapped donor electron spins in Si:P (phosphorous-doped silicon) has been studied by high frequency ESR. A sample with the donor concentration 6.5 x 1016 cm-3, where the sample is a insulator at low temperatures and the donor is almost isolated, was investigated at 2.87 T (80 GHz) from 48 K to 1.8 K by cw-ESR with field modulation. At low temperatures, where the spin-lattice relaxation time T1 changes in many orders of magnitude, the resonance line shape changed from the