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Soft Condensed Matter Physics

Introduction of Soft Condensed Matter

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Condensed matter physics is generally divided in "hard" and "soft" condensed matter physics. Soft matter refers to the myriad varieties of matter that form on the macroscopic scale, such as colloid, liquid crystals, polymers, biological structure and granular material. Here the physics, though collective, does not involve atomic forces and quantum mechanics, and the materials of interest are literally "softer".

 

 

Research on soft condensed matter physics in BIT mainly concerns the dynamic and static behavior of granular systems, namely large numbers of interacting particles that are much larger than a few microns and thus too large to be affected by Brownian motion. In granular materials thermal energies are irrelevant and this makes such systems outstanding candidates for investigating key issues in far-from-equilibrium physics.


Members

 

Qing-Fan Shi 

Professor of physics, received his PhD from Okayama University in 1998.  

qfshi123@bit.edu.cn


 

Ning Zheng
Associated professor of physics, received his PhD from University of Utah in 2007.

Ningzheng@bit.edu.cn



 

Ping-ping Wen 

Ph.D graduate student 

wenpingpingys@163.com

Cheng Xu 

Ph.D graduate student 

chengxu@bit.edu.cn

Research

1.  Segregation and patterns of granular mixtures

 

Granular materials when poured or shaken display a surprising range of collective behavior such as convection, size separation and pattern formation. Current project investigates the segregation behaviors of a granular mixture under vertical vibration, analyzing the features and mechanism of origin of segregation patterns.


 

2.  Statistical and dynamical properties of granular chains

 

The statistical properties and analogy of granular chain assemblies are our focus, since cleverly designed granular chains could act as an ideal experimental model to simulate or connect the properties of molecular chains such as polymers or proteins, and could potentially provide a way to uncover the physics that is experimentally inaccessible for micro-scale chain-like materials.


3.  Granular flow under vibration

Investigations on the flow properties of bulk solids, such as ores, grains and pharmaceuticals, have a wide application in conveyance, processing and storage of these materials. In nature, many important phenomena like avalanches, sandstorms, desert migration, and even traffic flow can be related to the bulk solids flow, or granular flow. In contrast to the flow of a viscous fluid, granular flow exhibits many exotic behaviors. For example, the discharge rate remains constant with decreasing depth of granular particles above the outlet.

The experimental system in previous studies only possesses one hole as the discharging outlet, and the diameter of the hole is usually larger than the critical diameter, in which the granular flow persists even without the external vibration. Therefore it is necessary to consider a limiting case where the size of the outlet is much smaller than the critical diameter to explore some underlying physics.


 

 

4.  Janssen effect at different boundaries

The static packing of granular materials confined in a container has been one of long-lasting issues due to its practical importance in many fields including civil engineering, soil science, and storage and processing of raw materials. It also can act as a simple but valid experimental system to test many theoretical models for the repartition or the transmission of stresses in granular materials. while the unity of basic physics remains unsolved. Measuring the stresses under various boundary conditions is very necessary for the establishment of the macroscopic constitutive relations of stress–strain. 

 

Selected publications

1.  Confinement-induced horizontal segregation in a vertically shaken granular bed, Xuejiao Yang, Ning Zheng, PingpingWen, Liangsheng Li, Qingfan Shi, Powder Technology 286 629–635 (2015)

2.  Flux of granular particles through a shaken sieve plate, Pingping Wen, Ning Zheng, Junwei Nian, Liangsheng Li and Qingfan Shi, Scientific Reports 5 09880 (2015)


3.  Bottom stresses of static packing of granular chains, PingPing Wen, Guan Wang, Degan Hao, Ning Zheng, Liangsheng Li, Qingfan Shi, Physica A 419 457–463 (2015)


4.  Symmetrically periodic segregation in a vertically vibrated binary granular bed Pingping Wen, Ning Zheng, Liangsheng Li and Qingfan Shi, Scientific Reports 4 6914 (2014)


5.  Scaling probability distribution of granular chains in two dimensions, Guan Wang, Ning Zheng, Pingping Wen, Liangsheng Li, Qingfan Shi, Physica A 407 192–197 (2014)


6.  Segregation in mixtures of granular chains and spherical grains under vertical vibration, Xiaoxian Yuan, Ning Zheng, Qingfan Shi, Gang Sun, and Liangsheng Li, PHYSICAL REVIEW E 87, 042203 (2013)


7.  Discrete particle simulation of radial segregation in horizontally rotating drum: Effects of drum-length and non-rotating end-plates, Ram Chand, Murad Ali Khaskheli, Abdul Qadir, Baoliang Ge, Qingfan Shi, Physica A, 391 4590–4596 (2012)


8.  Heaping instabilities in a layered Bi-disperse granular bed, Ning Zheng, Ping-Ping Wen, Qing-Fan Shi, Pik-Yin Lai and C. K. Chan, EPL, 100 44002 (2012)


9.  Polymerlike statistical characterization of two-dimensional granular chains, Ping-Ping Wen, Ning Zheng, Liang-Sheng Li, Heng Li, Gang Sun, and Qing-Fan Shi, Physical Review E, 85, 031301 (2012)


10.  Fluctuations in apparent mass at the bottom of granular columns due to different arrangements, Ram Chand, Qingfan Shi, Abdul Qadir, Shaopeng Ma, Gang Sun, Physica A 391 2936–2939 (2012)


11.  Percolation current in a periodic segregation of a binary granular mixture, Shanshan Du, Qingfan Shi, Gang Sun, Liangsheng Li, and Ning Zheng, PHYSICAL REVIEW E 84, 041307 (2011)


12.  Effect of the ratios of diameter of silo to bead on the pressure screening in granular columns, A. Qadir, H. Guo, X. Liang, Q. Shi and G. Sun. Eur. Phys. J. E 31, 311(2010)


13.  Size dependence of effective mass in granular columns, J. Liu, Q. Shi, X. Liang, L. Yang, G. Sun, Physica A 388 379-384 (2009)


14.  Density-driven segregation in vertically vibrated binary granular mixtures, Q. Shi, G. Sun, M. Hou, and K. Lu, PHYSICAL REVIEW E 75, 061302 (2007)


15.  Dynamics of a viscous ball rolling down on a rigid staircase, Hua Yan, Qingfan Shi, Decai Huang, Gang Sun, Physica A 374, 524-532 (2007)


16.  Criticality of the dilute-to-dense transition in a 2D granular flow, Jie Zhong, Meiying Hou, Qingfan Shi and Kunquan Lu, Journal of Physics Condensed Matter, 18(10):2789-2794 (2006)


17.  Effects of Air on the Segregation of Particles in a Shaken Granular Bed, X. Yan, Q. Shi, M. Hou, K. Lu and C. K. Chan, PHYSICAL REVIEW LETTERS, 91014302 (2003)


 

Contact us

Office 706, 745, Central teaching building

Beijing Institute of Technology

5 South Zhongguancun Street, Haidian District,

Beijing, 100081

 

Phone: (86) 10-68912632

Email: qfshi123@bit.edu.cn

      ningzheng@bit.edu.cn


 

 

Release date:2015-10-16