ASIAA/CCMS/IAMS/LeCosPA/NTU-Phys/NTNU-Phys Joint Colloquia

March 07, 2017

 Chung-Yuan Mou ,  NTU-Chemistry

Host:  Xiao-Gang He
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Nano-Confined Water

Abstract

Water under nano-confinement is different from normal water. It is relevant to life and geoscience because much of the hydration phenomenon in nature occurs in narrowly confined water. Studying confined water will help one to understand the physicochemical effect of water and its interaction with solutes in crowded environment. Mesoporous silica materials with uniform pore size will be the confining media in our study. By using neutron and X-ray scattering techniques, we studied the density and diffusion of water under nanoconfinement. By confining solutes, solubility of a hydrophobic molecule such as Xe in water under nanoconfinement will impact several related problems, (a) solubility of methane in water within nanopores of rock under fracking condition, (b) understanding how hydrophobic effect would be changed in confined water, (c) how protein hydration would change under confinement.
We studied hydration behavior of Xe in water confined in mesoporous silica using Xe-NMR chemical shifts. Temperature change of the signal allows us to determine the enthalpy of hydration. It was found that in pore confined water, the hydration of Xe is more energetically favorable than in bulk water. The increased solubility of Xe in nanopore is in the same trend with computer simulation results of confined methane.
Next, we employed mesoporous silica of matching pore sizes to confine lysozyme in order to mimic enzyme in a crowded environment. The stability and activity of lysozyme immobilized in mesoporous silica nanoparticle (MSN) of various pore sizes were studied and correlated to spectroscopic data of the immobilized enzyme. It was found that the activity of the lysozyme immobilized in the 5.6 nm mesopores of MSNs was higher than those of native enzymes. The enhanced activity was attributed to subtle change in hydration of lysozyme due to increased stability of hydrophobic solvation.

Brief Bio

男；民39年3月15日；台灣省基隆市
現職：國立臺灣大學化學系教授(民67-)。
學歷：國立臺灣大學化學系學士(民55-59)、美國華盛頓大學化學博士(民60-64)。
經歷：美國奧勒崗大學博士後研究(民64-66)、美國普渡大學博士後研究(民66-67)、臺灣大學化學系副教授(民67-71)、臺灣大學化學系教授 (民71-)、比利時布魯塞爾自由大學訪問學者(民72-73) 、台灣教育改革審議委員會委員(民82-84)、臺灣大學化學系主任(民93-96)、遠哲科學教育基金會董事(民87-100)、天下文化出版顧問(民 80-) 、國科會化學審議會學門召集人(民88-90)、奈米科技國家型計畫顧問(民91-96)、國家科學委員會副主任委員(民101-103)、國立台灣大學 講座教授(民103-)、中央研究院院士(民105)、亞洲太平洋催化聯盟主席(民105)
Live Streaming and Video

March 14, 2017

 Yia-Chung Chang ,  RCAS

Host:  Xiao-Gang He
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Multiscale Modeling of Optical and 

Transport Properties of Solids and 

Nanostructures

Abstract

Computation methods including density-functional theory (DFT), tight-binding (TB) as well as effective bond-orbital model (EBOM), and k.p model for calculation of optical and transport properties of solids and nanostructures will be discussed. Transport properties of nanostructure junctions modeled by non-equilibrium Green function method will also be presented. Examples include optical excitations of solids and nanostructures including the electron-hole interaction obtained within symmetry-adapted basis, time-dependent DFT calculations of optical excitations of semiconductor alloys, and tunneling current spectra as well as thermoelectric characteristics of coupled-quantum dot junctions.

Brief Bio

Yia-Chung Chang received his bachelor degree from National Cheng-KungUniversity, master degree and doctoral degree from California Institute of Technology. He joined the Physics Department, University of Illinois at Urbana-Champaign in 1980 as a visiting research assistant professor, and became an assistant professor in 1982, associate professor in 1986, and professor in 1991. In 2005, he joined Academia Sinica, Taiwan as a Distinguished Research Fellow and Director of the Research Center for Applied Sciences (RCAS). In 2012, he completed his two terms of directorship and remained as a Distinguished Research Fellow in RCAS. He is a fellow of American Physical Society and Academy of Nanoscience and Nanotechnology. He received the Distinguished Alumni Award of National Cheng-Kung University in 2009 and the Taiwan-France Science-technology Prize in 2015. He is a Thomson ISI highly cited scientist with nearly 10000 citations.
Dr. Yia-Chung Chang’s main research interests are in condensed matter theory, semiconductor electronics, photonic materials, and optoelectronic devices. In the last three decades he has worked on a series of related topics including shallow impurities and excitons in semiconductor superlattices and quatum wells, electronic and optical properties of semiconductors, surfaces and interfaces, and nanostructures, phonons and electron-phonon couplings in semiconductors and nanostructures, non-linear optical properties, many-body effects, exciton condensation, magnetic multilayers and giant magentoresistance, photonic crystals, optical metrology, detectors, lasers, quantum transport properties of nanostructures, spintronics, and quantum computing. Slides

March 21, 2017

Chao-Qiang Geng ,  NTHU-Physics

Host:  Xiao-Gang He
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Frontiers of Particle Physics 

and Cosmology: 

Neutrino, Dark Matter and Dark Energy 

Abstract

At present, the ordinary matter including Neutrino consists only about 5% of the total energy density of the Universe, while the rest, 27% and 68%, are Dark Matter and Dark Energy, respectively. These dark components have not been seen directly though the normal ways, based on electric and magnetics interactions. In this talk, I will give a brief review on the ordinary matter, particularly Neutrino, as well as Dark Matter and Dark Energy. I will explain why the studies of Neutrino, Dark Matter, and Dark Energy are the frontiers of the current research on Particle Physics and Cosmology. In the end, I will present some future perspectives.

Brief Bio


Chao-Qiang Geng received his Ph.D. degree in 1987 from Virginia Polytechnic Institute and State University, USA. He was the last student of Professor Robert E. Marshak, who was one of the founders for the theory of Weak Interactions. From 1987 to 1993, he was a Postdoctoral Research Associate in TRIUMF, Universite de Montreal and Iowa State University. He has been a faculty member at National Tsing Hua University since 1994. He has authored more than 280 papers in theoretical high energy physics. His research interests include preon, anomaly, axion, flavor physics and CP violation, and modified gravity. Currently, he has been working on the problems, related to neutrino masses, dark matter, dark energy, and the matter-antimatter asymmetry of the Universe.

Live Streaming and Video

March 28, 2017

 Chin-Shan Lue ,  NCKU-Physics

Host:  Tsyr-Yan Yu
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Introduction to Heusler compounds: 

From the case of Fe2VAl

Abstract

In this talk, I will introduce a type of materials called Heusler compounds (both full-Heusler and half-Heusler).
First, I will review a case of Fe2VAl since many important concepts in condensed matter physics were revealed from an intensive study of this material.
Later, I will mention some Heusler compounds with promising characteristics for possible thermoelectric and spintronic applications.
I will also briefly mention few novel Heusler compounds which have been proposed to possess topological properties.

Brief Bio

Ph.D., Physics, Texas A&M University, USA (09/1995 - 08/1999)
MS, Physics, National Tsing-Hua University, Taiwan (09/1989 - 06/1991)
BS, Physics, National Central University, Taiwan (09/1985 - 06/1989)
Academic Experience:
08/2007 – Present Professor, Department of Physics, National Cheng Kung University
08/2004 – 07/2007 Associate Professor, Department of Physics, National Cheng Kung University
08/2002 – 08/2004 Assistant Professor, Department of Physics, National Cheng Kung University
08/2001 – 07/2002 Assistant Professor, Department of Applied Physics, National Chia-Yi University
08/2000 – 07/2001 Postdoctoral Research, Department of Physics, National Sun-Yat-Sen University
07/1999 – 07/2000 Postdoctoral Research Associate, Department of Physics, Texas A&M University Slides

Live Streaming and Video

April 11, 2017

William Unruh,  UBC

Host:  Jiwoo Nam
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Gravity waves have been detected on Earth.

Abstract

About a year ago it was announced that gravitational waves have been detected on earth. What are Gravitational waves? How are they detected? How are they formed? What was actually seen? What created the detected waves? It is questions like these that this talk will address and answer.

Brief Bio

Prof. William George Unruh is a Canadian physicist at the University of British Columbia, Vancouver, who described the hypothetical Unruh effect in 1976. He obtained his B.Sc. from the University of Manitoba in 1967, followed by an M.A. (1969) and Ph.D. (1971) from Princeton University, New Jersey, under the direction of John Archibald Wheeler. Unruh has made seminal contributions to our understanding of gravity, black holes, cosmology, and quantum fields in curved spaces. He received Rutherford Memorial Medal (1982), Herzberg Medal (1983), Steacie Prize (1984), BC Science Council Gold Medal (1990), and Fellowship of American Physical Society and Royal Society of London (2001).

Live Streaming and Video

April 18, 2017

Ite A. Yu,  NTHU-Physics

Host:  Xiao-Gang He
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Slow and Stopped Light for Quantum Information Manipulation

Abstract

Slow light arising from the effect of electromagnetically induced transparency (EIT) greatly enhances the interaction time between photons and matters such that significant nonlinear optical efficiencies can be achieved even at single-photon level. Stopped light based on the EIT effect provides a method of exchange of wave functions between photons and matters and can lead to the application of quantum memory. The EIT-related research has made great impacts on quantum information science. In this talk, I will present our studies on low-light-level nonlinear optics and quantum memory utilizing slow and stopped light, and our experimental demonstration of two-component or spinor slow light.

Brief Bio

Education
Ph.D. in Physics, Massachusetts Institute of Technology (1993)
Employment
2015-present Distinguished Professor, National Tsing Hua University
2005-2015 Professor of Physics, National Tsing Hua University
2000-2005 Associate Professor, National Tsing Hua University
1995-2000 Associate Professor (tenure track), National Tsing Hua University
1993-1995 Postdoctral Researcher, Harvard-Smithsonian Center for Astrophysics
Honors and Awards
Outstanding Research Award, the Ministry of Science and Technology (2016/8~2019/7)
Outstanding Scholar Award, Foundation for the Advancement of Outstanding Scholarship (2016/8~2019/7)
Fellow of the Physical Society of R. O. C. Taiwan since 2014
Outstanding Scholar Award, Foundation for the Advancement of Outstanding Scholarship (2013/8~2016/7)
Outstanding Research Award, the Ministry of Science and Technology (2012/8~2015/7)
National Tsing Hua University Outstanding Mentor Award (2009)
Research Interests
slow light, storage of light, low-light-level nonlinear optics, quantum memory, quantum optics, quantum information manipulation, and cold atoms

April 25, 2017

 Yang-Yuan Chen ,  IoP AS

Host:  Ming-Wen Chu
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
The Physics and Energy Applications 
of Thermoelectric Materials

Abstract

First, I will give a brief introduction of the thermoelectric material (TE) about its past and future; basic researches and applications. At present, the efficiency of heat-electricity conversion is still far below that of photovoltaic solar panel, thus to improve its efficiency is the most significant work of the TE materials. The efficiency of thermoelectric conversion is represented by the dimensionless ZT (=σS^2T/κ), where σ is electrical conductivity, S is Seebeck coefficient, T is the absolute temperature and κ is the total thermal conductivity of electrons and phonons. Obviously, the way to enhance σS^2 and reduce κ become a strategy to raise ZT value.
In the talk, I will show a couple of examples of TE materials and the methods to enhance ZT, such as Zn4Sb3 crystals, Sb(2−x)In(x)Te3 (x=0–0.2) bulk, topological insulator Bi1.5Sb0.5Te1.7Se1.3 nanowires, and the recent hot topic of SnSe crystal. At the end, I will show you a micro TE electrical generator for the possible application in our daily life.

Brief Bio

I. PRESENT POSITION AND PERSONAL INFORMATION:
Academia Sinica Senior Research Fellow, Physics 1993-
National Chung Shing Univ. Professor, Joint appointment, Physics 2005-
National Chengchi Univ. Professor, Joint appoint, Physics. 2008-
II. DEGREES:
B.S. Department of Physics, Soochow University 1977
M.S. Department of Physics, University of California, Irvine 1983
Ph.D. Department of Physics, University of California, Irvine 1987
III. FIELDS OF RESEARCH INTEREST:
Low temperature physics, high-pressure and calorimetry, heavy Fermion, nanoscience, biophysics, thermoelectricity, renewable energy
IV. PLENARY OR INVITED LECTURES (in 5 years)
Plenary lectures:
1. 2013 Taiwan-Japan Thermoelectric technology workshop, Taipei, 4/22, 2013
2. 2nd International Conference on Frontiers in Nano Science, Technology and Applications, Andhra Pradesh, India, 12/20-22, 2014
3. Leading talk, 4th International Conference on Sustainable Energy Engineering and Application (ICSEEA 2016), Jakarta, Indonesia, 10/3-5, 2016
Invited lectures：
1. Collaborative Conference on Materials Research (CCMR), Jeju Island, South Korea, 6/24-28, 2013
2. International Union of Materials Research Societies-International Conference on Electronic Materials (IUMRS-ICEM), Taipei, 6/10-14, 2014
3. 2015 Symposium for the Promotion of Applied Research Collaboration in Asia (SPARCA 2015) Taipei, Taiwan, 2/8-11 2015
4. The 2nd NIMS-Taiwan MOST Workshop, Tsukuba, 4/21- 23, 2015
5. 兩岸熱電材料及應用交流論壇, Taipei 4/28-29, 2015
6. EMN Meeting on Thermoelectric Materials , Orlando, FL USA, 2/21-25, 2016
7. The 35th International Conference & The 1st Asian Conference on Thermoelectricis, Wuhan, China, 5/29-6/2, 2016
8. 2017 TMS annual meeting in San Diego, California, USA, 2/26-3/2, 2017

Live Streaming and Video

May 02, 2017

 Wei Pan ,  Sandia National Laboratories

Host:  Yuan-Huei Chang
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Quantum Hall Effect in Vanishing 
Magnetic Fields

Abstract

Soon after the discovery of the quantum Hall effects in two-dimensional electron systems, the question on the fate of the extended states in a Landau level in vanishing magnetic (B) field arose. Many theoretical models have since been proposed, and experimental results remain inconclusive. In this talk, we report experimental observation of anti-levitation behavior of Landau levels in vanishing B fields (down to as low as B ~ 58 mT) in a high quality heterojunction insulated-gated field-effect transistor (HIGFET). We observed that, in the Landau fan diagram of electron density versus magnetic field, the positions of the magneto-resistance minima at Landau level fillings ν=4, 5, 6 move below the “traditional” Landau level line to lower electron densities. This clearly differs from what was observed in the earlier experiments where in the same Landau fan plot the density moved up. Our result strongly supports the anti-levitation behavior predicted recently. Moreover, the even and odd Landau level filling states show quantitatively different behaviors in anti-levitation, suggesting that the exchange interactions, which are important at odd fillings, may play a role.

Brief Bio

Dr. Wei Pan is a Distinguished Member of the Technical Staff at Sandia National Laboratories. He was a recipient of the Presidential Early Career Award for Scientists and Engineers. His research focuses on the quantum Hall effects in two-dimensional electron systems. He was a member of organizing and program committees of several international conferences, and has served as a member of Users Advisory Committee for the National High Magnetic Field Laboratory.

About Sandia: Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Slides

May 09, 2017

Ting-Kuo Lee,  IoP AS

Host:  Xiao-Gang He
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
The New Phase in the Strongly 
Correlated Electronic Systems

Abstract

Since the discovery about thirty years ago, cuprate high temperature superconductor is known to be a standard material exhibiting strong correlation effect. The experiments have continuously reported many exotic properties, like broken Fermi surfaces, the pseudogap at normal state, and two energy gaps at the superconducting state, etc. More surprises have been reported recently about the presence of various charge density waves with different periods and form factors in different cuprate families. These states are seen in the superconducting and normal phases. There are evidences that these states also involve spatial modulation of pairing amplitude, or a pair density wave, and/or spin density waves. This new phase of states with intertwined orders span most of the underdoped region in the phase diagram of cuprates.
Taking into account the strong correlation in a minimal t-J type model, we found many nearly degenerate inhomogeneous ground states. These states with spatial modulations of charge density and pairing amplitudes could also have modulations of spin moments when the dopant density is small. A number of properties and spectra of these states were computed and compared with the data reported by the scanning tunneling microscopy and the angle-resolved photoemission spectra for cuprates. The excellent agreement with experiments leads us to a better understanding of the origin of the many exotic phenomena in cuprates. It also gives us insights into the effect of strong correlation.

Brief Bio

Dr. Ting-kuo Lee is a Distinguished Research Fellow and Director of the Institute of Physics, Academia Sinica, Taiwan. He has been widely recognized in the area of theoretical condensed-matter physics, including being named a Fellow of the American Physical Society, the Institute of Physics in UK, and Physical Society of Republic of China.
He has made seminar contribution to the understanding of strongly correlated electronic systems, in particular, high temperature superconductors. He has been also heavily involved in the development of nano science and nano technology in Taiwan. He was the Director of the National Program of Nanoscience and Nanotechnology in 2004-2006, and the Innovation and Application of Nanoscience Thematic Program (IANTP) since 2014. He also has served as the Director of Academia Sinica Research Program on Nanoscience and Nanotechnology since 2004.
Dr. Lee’s Research Interest:
Strongly correlated electronic materials, superconductivity, thermal electric materials, novel quantum materials, optimization method, electron and x-ray coherent diffraction imaging, 3D image segmentation, reconstruction and quantitative analysis

May 16, 2017

Eung Jin Chun,  KIAS

Host:  Xiao-Gang He
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
After the Higgs

Abstract

The Standard Model (SM) of particle physics was finally completed by the discovery of the Higgs boson at the LHC in 2012. However, we believe that SM cannot be the final story guided by the theoretical argument for the weak-scale stability and by the experimental evidences for the existence of dark matter and neutrino masses.Thus we are desperately waiting for new signals which may reveal the face of theory beyond SM. After reviewing the basic elements of the SM and beyond, we will briefly discuss a new physics model of Type II seesaw which predicts a peculiar collider signals like same-sign tetra-leptons.

Brief Bio

Professor Eung Jin Chun majorly works on supersymmetric extensions of axion models; neutrino mass models and their collider signatures.
Education and Experience
Ph. D, Seoul National University, 1991
Research fellow, Technical University of Munich, Germany
Research fellow, International Center for Theoretical Physics, Trieste, Italy
Research professor, Chungbuk National University
Research fellow, Korea Institute for Advanced Study
Research professor, Seoul National University
Professor, Korea Institute for Advanced Study, 2002

Live Streaming and Video

May 22, 2017

Gabriela González ,  Louisiana State University

Host:  You-Hua Chu
Time: 1:30 pm -2:30 pm
Place: 1F Auditorium, Astronomy-Mathematics Building, 
           NTU/AS
Title:
Searching for – and finding! gravitational waves

Abstract

On September 14 2015, the two LIGO gravitational wave detectors in Hanford, Washington and Livingston, Louisiana registered a nearly simultaneous signal with time-frequency properties consistent with gravitational-wave emission by the merger of two massive compact objects. Further analysis of the signals by the LIGO Scientific Collaboration and the Virgo Collaboration revealed that the gravitational waves detected by LIGO came from the merger of a binary black hole system. This observation, followed by another one in December 2015, marked the beginning of gravitational wave astronomy. I will describe some details of the observation, the status of LIGO and Virgo ground-based interferometric detectors, and prospects for future observations.

Brief Bio

Prof. González has been a member of the LIGO Scientific Collaboration since 1997, and in 2011 she was elected as its spokesperson. Her group is involved with the characterization of the noise in the LIGO detectors, the calibration of the detectors, and the analysis of the data. In analyzing the data, she searches for the waves produced by binary systems of compact stars in their final orbits before coalescing into a single black hole. Prof. González is a Fellow of the American Physical Society and has won numerous honors and awards, including the Edward A. Bouchet Award of the American Physical Society, Jesse W. Beams Award of the Southeastern Section of American Physical Society, Gruber Cosmology Prize of the International Astronomical Union, Manne Siegbahn Medal from AlbaNova University Center (Stockholm), the 2017 Rossi Prize from AAS, etc. Most notably, Prof. González has been selected as Nature’s 10 People Who Mattered This Year in 2016.

The 3rd KAGRA International Workshop

May 23, 2017

Shinya Kanemura,  Osaka University

Host:  Cheng-Wei Chiang
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Higgs as a Probe of New Physics

Abstract

The Higgs boson was discovered and its measured property turned out to be consistent with that in the standard model within the current experimental uncertainty. However, the nature of the Higgs boson, the multiplet structure of the Higgs sector and the physics behind the electroweak symmetry breaking remain unknown. On the other hand, there are many reasons to consider new physics beyond the standard model. Details of the Higgs sector are expected to be strongly related to new physics.
In this talk, we discuss various aspects of "non-minimal" Higgs sectors and their relation to new physics scenarios. We then discuss how the structure of the Higgs sector can be explored by current and future experiments. We emphasize that the Higgs sector is an important probe of the new physics beyond the standard model.

Brief Bio

Prof. Shinya Kanemura is a professor at the Physics Department of Osaka University. He works on elementary particle phenomenology, with many renown works in Higgs boson physics within and beyond the Standard Model. In recent years, he plays a leading role in pushing for the construction of International Linear Collider in Japan.

Live Streaming and Video

June 06, 2017

 Changbom Park ,  KIAS

Host:  Keiichi Umetsu
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Cosmology with the Large-scale Structures

of the Universe

Abstract

In the first part of my talk I will briefly review sciences with the large-scale structures of the universe. In particular, I will introduce how the growing galaxy redshift data can be used to constrain cosmological models and galaxy formation theories. In the second part a new method for measuring the cosmological parameters governing the expansion history of the universe will be introduced. The method uses the Alcock-Paczynski (AP) test applied to the overall shape of the galaxy two-point correlation function along and across the line-of-sight. We applied this method to simulated data and also to a recent galaxy survey data to obtain an impressive constraint on the dark energy equation of state and matter density parameter Ωm.

Brief Bio

Prof. Changbom Park is a world-renowned observational cosmologist, who studies the cosmic microwave background radiation, large-scale structure of the universe, and galaxies to understand the nature of the universe and the galaxy formation process. Prof. Park received his Bachelor's degree (1983) in Astronomy from Seoul National University, Korea and his PhD (1991) in Astronomy from Princeton University, USA.
He joined as Professor in the Department of Astronomy, Seoul National University in 1992. Since 2003, he has been a Professor in the School of Physics, Korea Institute for Advanced Study (KIAS). He has created the Center for Advanced Computation in KIAS, and is currently the chairman of the KIAS School of Physics. He has been the Editor of the Journal of the Korean Astronomical Society during the past 7 years. Prof. Changbom Park constrains cosmological models and galaxy formation theories by comparing the results of cosmological simulations with observations. He works on topology of large-scale structure, and was one of the first to measure the power spectrum of galaxy distribution.

Live Streaming and Video

June 13, 2017

Wei-Min Zhang,  NCKU-Physics

Host:  Xiao-Gang He
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Physics of Open Systems

Abstract

In this talk, I will introduce a general theory of open systems we developed in the last few years. The fundamental physics of open quantum systems, including topics of nonequilibrium dynamics, non-Markovianity memory phenomena, entanglement decoherence and decoherence of topological states, quantum thermalization, nonequilibrium quantum phase transition, and quantum transport, etc. are explored. Applications to various open systems are also presented.
Related references:
[1] M. W. Y. Tu and W. M. Zhang, Phys. Rev. B 78, 235311 (2008).
[2] J. S. Jin, M. W. Y. Tu, W. M. Zhang, and Y. J. Yan, New. J. Phys. 12, 083013 (2010).
[3] C. U Lei and W. M. Zhang, Ann. Phys. 327, 1408 (2012).
[4] W. M. Zhang, P. Y. Lo, H. N. Xiong, M. W. Y. Tu and F. Nori, Phys. Rev. Lett. 109, 170402 (2012).
[5] P. Y. Yang, and C. Y. Lin and W. M. Zhang, Phys. Rev. B 92, 165403 (2015).
[6] P. Y. Yang and W. M. Zhang, Front. Phys. 12, 127204 (2017).


Brief Bio

Education Background
Ph. D. in Physics (1986-1989) Department of Physics, Drexel University
B. S. in Physics (1978-1982) Department of Physics, Soochow University
Professional Experiences:
Distinguished Professor (2004-) Department of Physics, National Cheng-Kung University
Professor (1999-) Department of Physics, National Cheng-Kung University
Visiting Associate Professor (1994-1995, 1997-1998) Institute of Physics, Academia Sinica
Visiting Associate Professor (1996) Department of Physics, National Tsing Hua University
Postdoctoral Research Fellow (1992-1993) Department of Physics, The Ohio-State University
Postdoctoral Research Associate (1989-1991) Department of Physics, University of Washington
Research Interests
Quantum computation and quantum information
Nonequilibirum dynamics and open quantum systems
Quantum decoherence and non-Markovian phenomena
Quantum transport theory and nanostructures
Strong correlated many-body physics
Quantum chromodynamics (QCD) and light-front field theory
Quantum chaos and quantum nonintegrability
Nuclear physics and quantum phase transitions


Slides

June 20, 2017

Nae-Lih Wu,  NTU-Chemical Engineering

Host:  Ming-Wen Chu
Time: 2:20 pm -3:20 pm
Place: Room 104, CCMS-New Phys. building
Title:
Research on Li-S Batteries

Abstract

Lithium-sulfur (Li-S) battery is a promising rechargeable battery system that has both high theoretical capacity and energy density. Moreover, sulfur (S) is inexpensive and nontoxic, making Li-S suitable for large-scale energy storage applications. However, there exist major hurdles to be overcome before the realization of its practical applications. On the cathode side, sulfur lithiation during the operation of Li-S battery is a multi-step electrochemical process that involves different lithium polysulfide (Li2Sn, 1≦n≦8) intermediates. The long-chain polysulfides are highly soluble in the aprotic organic electrolyte. Polysulfide dissolution is strongly linked to the deterioration of several key performance indexes, such as coulombic efficiency, self-discharge, capacity fading and etc., of Li-S batteries.
Furthermore, the starting S cathode and lithiated end product Li2S are both electrically and ionically insulating, and the rate performance of Li-S batteries is another challenge. High rate performance has relied mainly on the specially tailored nanostructured conductive carbon (C) materials, but it is expected to substantially increase manufacturing and material costs for the electrode, offsetting the low-cost advantage of S.
On the anode side, major challenges for Li metal anodes are rooted in the dendritic Li deposits on metal substrates. Li dendrite growth can cause low Columbic efficiency, infinite volume expansion, accelerated electrolyte decomposition, and even penetration of the separator to trigger short-circuit and thermal runaway.
In this talk, recent research activities in the Energy Materials Laboratory at ChE, NTU dealing with the aforementioned critical issues of Li-S batteries will be presented.

Brief Bio

Prof. Nae-Lih Wu is currently a Distinguished Professor in the Department of Chemical Engineering at National Taiwan University (NTU). He received Ph.D. in Chemical Engineering from Pennsylvania State University in 1987. His research interests include:
1. synthesis and characterization of electrode and component materials for electrochemical devices, including supercapacitors and Li-ion batteries;
2. development of advanced in-situ/in-operando analytic methodologies based on synchrotron facilities in charactering these materials and devices;
3. nano-materials synthesis and applications.
Prof. Wu once served as a Consultant to the Ministry of Economic Affairs in Taiwan, Director of the Energy Research Center, Chairman of the Chemical Engineering Department at NTU, and an editorial board member of Journal of Power Sources. He has over 130 refereed papers, 9 Taiwan patents, and 4 U.S. patents. He is currently serving as an Associate Editor for Electrochemical Society Journals.

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