Hoạt động
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Seminar
| Seminar Vật lý lý thuyết và Vật lý tính toán:
| | Tên báo cáo | The Role of Quenched Disorder, Interfaces and Confinement on Glassy Dynamics of Colloidal and Thermal Liquids
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| Người trình bày | Phan Đức Anh
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| Cơ quan | Đại học Illinois tại Urbana-Champaign, Hoa Kỳ
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| Ngày | Thứ Ba, 30-08-2016
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| Giờ | 10:00 AM
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| Địa điểm | Phòng 202 (Thư viện), Viện Vật lý, 10 Đào Tấn, Ba Đình, Hà Nội
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| Tóm tắt | Understanding slow glassy dynamics of colloidal and thermal (molecular, metallic, polymer) fluids in the presence of quenched disorder, interfaces and confinement is of importance for both industrial applications and fundamental science. Recent experimental and simulation studies have shown that confinement has a significant influence on the dynamics but the mechanism underlying this phenomenon is likely nonuniversal and has not been formulated based on fundamental statistical mechanics. In this research, we determine qualitatively and quantitatively the dynamics of confined systems using relatively simple models, make testable predictions and compare to experiments to treat dynamical arrest, the shear modulus and alpha relaxation time for two classes of systems. First, mobile colloids immersed in quenched nanofiber network where the dynamical arrest can be formed mainly via physical bonding at low colloidal volume fraction. Variation of intercolloid and interfacial attractions significantly modifies not only the localized states and dynamic shear modulus, but also colloidal adsorption and desorption. Second, we propose a theoretical framework for the dynamics of bulk isotropic hard-sphere particle systems in the presence of randomly pinned particles, and apply this theory to real thermal liquids. The slow dynamics is induced by a stronger local caging constraint and modification ("screening") of the long range elasticity aspect of relaxation. Our theoretical analysis for the relaxation time of water with random pinned molecules are in rather good agreement with previous simulations. The dynamical effects of pinned particles depend on the "softness" of pinning. The influence of adsorption on pinning particles will be studied.
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| Người chủ trì | Trịnh Xuân Hoàng
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