To, Kiwing / Research Fellow


Contact Information



ericto [at]

My Website


  • University of Pittsburgh, M. Sc. (1985), Ph. D. (1990),
  • The Chinese University of Hong Kong, B. Sc. (1982)


Rao, Cindy / 886-2-2789-8916

cindy14 [at]

Research Interest

  • Physics of Granular Materials
  • Phase Transitions and Critical Phenomenon, Polymer Physics
  • Physics of Fluids, Electrorheological Fluids


  • Postdoctoral Research Fellow, Universite Paris VI, France
  • Postdoctoral, Assistant, Associate Research Fellow, Institute of Physics Academia Sinica


Journal Papers

  • [1]     Kiwing To*, Yi-Kai Mo, Tivadar. Pongó, Tamas. Börzsönyi, 2021, “Discharge of elongated grains from silo with rotating bottom”, Physical Review E, 103, 062905. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [2]     D. Hernández-Delfin, T. Pongó, K. To, T. Börzsönyi, and R. C. Hidalgo, 2020, “Particle flow rate in silos under rotational shear”, PHYSICAL REVIEW E, 102, 042902. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [3]     Siu, K. T., Y. Xu, Y. M. Tai, T. Choi, K. Michael Wong and K. To, 2020, “Switching Behavior and Control Policy of Congestion: Examples from Taiwan Highway System”, New Mathematics and Natural Computation, 16 (3), 657-667. (ESCI)

  • [4]     Kiwing To*, Yun Yen, Yi-Kai Mo, and Jung-Ren Huang, 2019, “Granular flow from silos with rotating orifice”, PHYSICAL REVIEW E, 100, 012906. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [5]     Diego López-Rodríguez, Diego Gella, Kiwing To, DiegoMaza, Angel Garcimartín, and Iker Zuriguel*, 2019, “Effect of hopper angle on granular clogging”, Physical Review E, 99, 032901. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [6]     Kiwing To*, Hsiang-Ting Tai, 2017, “Flow and clog in a silo with oscillating exit”, Phys. Rev. E, 96, 032906. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [7]     Zheng Peng, Kiwing To*, 2016, “Biased Brownian motion in narrow channels with asymmetry and anisotropy”, PHYSICAL REVIEW E, 94, 022902. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [8]     Rui Liu, Mingcheng Yang*, Ke Chen*, Meiying Hou* and Kiwing To*, 2016, “Coupled Leidenfrost states as a monodisperse granular clock”, PHYSICAL REVIEW E, 94, 020901(R). (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [9]     Y. C. Chou*, Yi-Feng Hsiao, Gwo-Jen Hwang and Kiwing To, 2016, “Torque generation through the randommovement of an asymmetric rotor: A potential rotational mechanism of the γ subunit of F1-ATPase”, PHYSICAL REVIEW E, 93, 022408. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [10]     Y. C. Chou*, Yi-Feng Hsiao, Kiwing To, 2015, “Dynamic model of the force driving kinesin to move along microtubule—simulation with a model system ”, PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS, 433, 66-73. (SCIE) (IF: 3.263; SCI ranking: 32.6%)

  • [11]     Kiwing To*, 2014, “Boltzmann distribution in a nonequilibrium steady state: Measuring local potential by granular Brownian particles”, PHYSICAL REVIEW E, 89, 062111. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [12]     Pei-Ren Jeng, KuanHua Chen, Gwo-jen Hwang, Ethan Y. Cho, Chenhsin Lien, Kiwing To, Y. C. Chou*, 2014, “Entropic force on granular chains self-extracting from one-dimensional confinement”, JOURNAL OF CHEMICAL PHYSICS, 140,, 024912. (SCIE) (IF: 3.488; SCI ranking: 50%,24.3%)

  • [13]     KuanHua Chen, Y. C. Chou, Kiwing To, 2013, “Force generation by granular chains moving randomly on periodic ratchet plates”, PHYSICAL REVIEW E, 87, 012711. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [14]     Chung-Yi Li*, Yuan-Ho Chen, Tsin-Yuan Chang, Lih-Yuan Deng, Kiwing To, 2012, “Period Extension and Randomness Enhancement Using High-Throughput Reseeding-Mixing PRNG”, IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS, 20, 385. (SCIE, EI) (IF: 2.312; SCI ranking: 50.9%,55.7%)

  • [15]     Pei-Ren Jeng, Kuan Hua Chen, Gwo-jen Hwang, Chenhsin Lien, Kiwing To, and Y. C. Chou2, 2011, “Collapse kinetics of vibrated granular chains”, JOURNAL OF CHEMICAL PHYSICS, 135, 244903. (SCIE) (IF: 3.488; SCI ranking: 50%,24.3%)

  • [16]     P.-R. Jeng, K. H. Chen, G.-J. Hwang, C.-M. Tien, C. Lien, K. To, Y. C. Chou*, 2011, “Packaging of granular bead chain”, EUROPHYSICS LETTERS, 96, 44005.

  • [17]     C. C. Liao, S. S. Hsiau, and Kiwing To*, 2010, “Granular dynamics of a slurry in a rotating drum”, PHYSICAL REVIEW E, 82, 010302. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [18]     Guoqi Hu, Yinchang Li, Meiying Hou* and Kiwing To, 2010, “Traveling shock front in quasi-two-dimensional granular flows”, Physical Review E, 81, 011305. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [19]     Wennan Chen and Kiwing To*, 2009, “Unusual diffusion in a quasi-two-dimensional granular gas”, PHYSICAL REVIEW E, 80, 061305. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [20]     TaYon Wang and Kiwing To, 2007, “Granular gas in a vibrating box”, CHINESE JOURNAL OF PHYSICS, 45, 675. (SCIE) (IF: 3.237; SCI ranking: 33.7%)

  • [21]     Kiwing To*, 2005, “Phase transitions of gravity driven granular flow”, MODERN PHYSICS LETTERS B, 28,1. (SCIE) (IF: 1.668; SCI ranking: 71.3%,75.4%,41.8%)

  • [22]     To K, 2005, “Jamming patterns in a two-dimensional hopper”, PRAMANA-JOURNAL OF PHYSICS, 64((6): Sp. Iss. SI), 963-969. (SCIE) (IF: 2.219; SCI ranking: 50%)

  • [23]     Kiwing To*, 2005, “Jamming transition in two-dimensional hoppers and silos”, PHYSICAL REVIEW E, 71, 060301. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [24]     Kiwing To* and Pik-Yin Lai, 2002, “Jamming pattern in a two-dimensional hopper”, PHYSICAL REVIEW E, 66, 011308. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [25]     Kiwing To, 2001, “Coexistence curve exponent of a binary mixture with a high molecular weight polymer”, PHYSICAL REVIEW E, 63, 026108. (SCIE) (IF: 2.529; SCI ranking: 35.3%,14.5%)

  • [26]     Kiwing To*, Pik-Yin Lai, and H. K. Pak, 2001, “Jamming of Granular Flow in a Two-Dimensional Hopper”, PHYSICAL REVIEW LETTERS, 86, 71. (SCIE) (IF: 9.161; SCI ranking: 8.1%)

  • [27]     Jui-Hung Hsu, Wunshain Fann, Hsin-Fei Meng, En-Shi Chen, En-Chung Chang, Shaw-An Chen, Ki-Wing To, 2001, “Decay dynamics of interchain excited states in luminescent conjugated polymer CN-PPV”, CHEMICAL PHYSICS, 269,367. (SCIE) (IF: 2.348; SCI ranking: 69.8%,45.9%)

  • [28]     H. J. Choi, J. W. Kim, M. S. Suh, M. J. Shin, K. To, 2001, “Synthesis and viscoelastic behaviors of poly(aniline-co-o-ethoxyaniline) particles suspended electro-rheological fluid”, INTERNATIONAL JOURNAL OF MODERN PHYSICS B, 15, 649. (SCIE) (IF: 1.219; SCI ranking: 84.4%,84.1%,61.8%)

  • [29]     H. J. Choi, J. M. Kim, Kiwing To, 1999, “Electrorheological characteristics of semiconductive poly(aniline-co-o-ethoxyaniline) suspensions”, POLYMER, 40, 2163. (SCIE) (IF: 4.43; SCI ranking: 17.6%)

  • [30]     Ji W. Kim, H. J. Choi, Kiwing To, 1999, “Electrorheological Properties of Poly(Aniline-co-o-Ethoxyaniline)”, POLYMER ENGINEERING AND SCIENCE, 39, 1493. (SCIE) (IF: 2.428; SCI ranking: 56.6%,52.7%)

  • [31]     H. J. Choi, J. M. Kim, Kiwing To, 1999, “Synthesis and Electrorheological Behavior of Semiconducting Poly(aniline-co-o-ethoxyaniline)”, SYNTHETIC METALS, 101, 697. (SCIE) (IF: 3.266; SCI ranking: 51.8%,43.5%,36.3%)

  • [32]     Kiwing To* and Hyoung J. Choi, 1998, “Polymer Conformation near the Critical Point of a Binary Mixture”, PHYSICAL REVIEW LETTERS, 80, 536. (SCIE) (IF: 9.161; SCI ranking: 8.1%)

  • [33]     Kiwing To, Chul A. Kim, Hyoung J. Choi, 1998, “Abnormal scattering of polymer in binary solvent, Physica A254, 292, 1998.”, PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS, 254, 292. (SCIE) (IF: 3.263; SCI ranking: 32.6%)

  • [34]     H. J. Choi, M. S. Cho, Kiwing To, 1998, “Effect of ionic pendent of polyaniline based electrorheological fluid”, MACROMOLECULAR RAPID COMMUNICATIONS, 19, 271. (SCIE) (IF: 5.734; SCI ranking: 9.9%)

  • [35]     Ki-Wing To, H. J. Choi, 1998, “Electrorheological and dielectric characteristics of semi-conductive polyaniline-silicone oil suspensions”, PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS, 254, 272. (SCIE) (IF: 3.263; SCI ranking: 32.6%)

  • [36]     Ki-Wing To, 1997, “Electrical Resistance of a Phase Separating Binary Liquid Mixture in Random Packing of Glass Beads”, PHASE TRANSITIONS, 60, 97. (SCIE) (IF: 1.452; SCI ranking: 69.2%,81.2%)

  • [37]     Ki-Wing To, 1996, “Morphological Transitions of Diffusion Limited Aggregate under Outward Radial Drift”, CHINESE JOURNAL OF PHYSICS, 34, 1175. (SCIE) (IF: 3.237; SCI ranking: 33.7%)

  • [38]     Ki-Wing To, 1995, “Measurement of flow speed from video images of demixing liquid-liquid system using spatial-temporal Fourier spectral method”, REVIEW OF SCIENTIFIC INSTRUMENTS, 66, 2935. (SCIE) (IF: 1.523; SCI ranking: 71.9%,77.5%)

  • [39]     Ki-Wing To, Chi-Keung Chan, H. J. Choi, 1995, “Phase Equilibrium and Conformation of a Polymer in a Binary Solvent”, PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS, 223, 232. (SCIE) (IF: 3.263; SCI ranking: 32.6%)

  • [40]     Ki-Wing To, Chi-Keung Chan, 1994, “Morphology and Dynamics of a Separating Immiscible Binary Liquid Mixture under Gravity”, PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS, 205, 320. (SCIE) (IF: 3.263; SCI ranking: 32.6%)

  • [41]     Ki-Wing To, Chi-Keung Chan, 1993, “Dynamics of Demixing of Binary Liquid Mixtures in an Inclined Cylinder”, Europhys. Lett., 24, 365.

  • [42]     K. To, S. Akamatsu, F. Rondelez, 1993, “Stripe Phase in the Gas-Liquid Coexistence Region of Langmuir Monolayers”, Europhys. Lett., 21, 343.

  • [43]     Silvère Akamatsu, Othman Bouloussa, Kiwing To, and Francis Rondelez*, 1992, “Two-dimensional dendritic growth in Langmuir monolayers of d-myristoyl alanine”, PHYSICAL REVIEW A, 46, R4504(R). (SCIE) (IF: 3.14; SCI ranking: 31.3%,27%)

  • [44]     Ki-Wing To, Chi-Keung Chan, 1992, “Scaling Behaviour in the Demixing of a Binary-Liquid Mixtures under Gravity”, Europhys. Lett., 19, 311.

  • [45]     K. To and F. Rondelez, 1991, “Fluorescent microscope observations of domain shape transition due to long-range dipolar repulsion in the gas-liquid coexistence region of a Langmuir monolayer”, COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE II FASCICULE C-CHIMIE, 311, p599.

Conference Papers

  • [1]     Kiwing To*, C. S. Wang, Tyne Liang, 2010, “Word ordering Entropy difference of English and Chinese texts”, 600 pages, paper presented at International Computer Symposium 2010, Tainan, Taiwan: Computer Society of the Republic of China, 2010-12-16 ~ 2010-12-18.

  • [2]     Kiwing To and Sy-Sang Liaw, 2007, “Chinese Journal of Physics”, paper presented at Workshop on Nonlinear Physics,2006, 2007-12.

  • [3]     Kiwing To and Sy-Sang, 2007, “Workshop on Nonlinear Physics, 2006”, Volume. 45, Number 6, Part II pages, paper presented at Chinese Journal of Physics, 2007-12.


  • [1]     西元年:2001
    研究人員(英):TO, KI-WING, Pik-Yin Lai, H. K. Park
    研究成果名稱(英):Jamming of granular flow
    簡要記述(英):It is common knowledge that the flow rate of grains out of a hopper increases with the hopper opening. However, when the hopper opening is comparable to the size of the grain, jamming occurs unpredictably. From observations in experiments and computer simulations, it had been known qualitatively that jamming was due to the formation of an arch before the hopper opening that block the flow. Nevertheless, a quantitative prediction of the probability of jamming is still lacking. We started an extensive study of the jamming phenomenon for mono-disperse disks falling through 2-dimensional hoppers in which the position of every disk is recorded in each jamming event. Then the disk configuration of the jam causing arch was mapped to a trajectory of a restricted random walker (RRW). From the statistics of the RRW trajectories and we estimated the jamming probability as a function of the hopper opening and we found that the statistics of the jamming arch and the probability of jamming obtained in our experiment agreed very well with the theoretical predictions. This work was published in Physical Review Letters and reported in Physical Review Focus. On January 9, 2001 this work was introduced to the general public by an article in New York Times written by Dr. James Glanz. A interview with Dr. Kiwing To on this topic was broadcast by the Radio Taiwan International.
    Kiwing To*, Pik-Yin Lai, and H. K. Pak, 2001, “Jamming of Granular Flow in a Two-Dimensional Hopper”, PHYSICAL REVIEW LETTERS, 86, 71. (SCIE) (IF: 9.161; SCI ranking: 8.1%)

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