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Zi Kui Liu

Bio: Zi Kui Liu is an academic researcher from Pennsylvania State University. The author has contributed to research in topics: CALPHAD & Phase diagram. The author has an hindex of 72, co-authored 654 publications receiving 21388 citations. Previous affiliations of Zi Kui Liu include Foundation University, Islamabad & Xiamen University.


Papers
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TL;DR: The proposed method optimizes the shape of the supercell jointly with the occupation of the atomic sites, thus ensuring that the configurational space searched is exhaustive and not biased by a pre-specified supercell shape.
Abstract: We present a new algorithm to generate Special Quasirandom Structures (SQS), i.e., best periodic supercell approximations to the true disordered state for a given number of atoms per supercell. The method is based on a Monte Carlo simulated annealing loop with an objective function that seeks to perfectly match the maximum number of correlation functions (as opposed to merely minimizing the distance between the SQS correlation and the disordered state correlations for a pre-specified set of correlations). The proposed method optimizes the shape of the supercell jointly with the occupation of the atomic sites, thus ensuring that the configurational space searched is exhaustive and not biased by a pre-specified supercell shape. The method has been implemented in the “mcsqs” code of the Alloy Theoretic Automated Toolkit (ATAT) in the most general framework of multicomponent multisublattice systems and in a way that minimizes the amount of input information the user needs to specify and that allows for efficient parallelization.

896 citations

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TL;DR: In this paper, the stability and evolution of ferroelectric domain structures in thin films are studied and Elastic solutions are derived for both elastically anisotropic and isotropic thin films with arbitrary domain structures, subject to mixed stress-free and constraint boundary conditions.

446 citations

Journal ArticleDOI
TL;DR: In this article, the thermodynamic properties of Al, Ni, NiAl, and Ni3Al were studied using the first-principles approach using the ab initio plane wave pseudopotential method within the generalized gradient approximation.

441 citations

Journal ArticleDOI
TL;DR: Here it is shown that an in situ process in which MgB2 is formed directly on the substrate is desirable and can be achieved by hybrid physical–chemical vapour deposition, and this advance removes a major barrier for superconducting electronics using M gB2.
Abstract: The newly discovered 39-K superconductor MgB2 holds great promise for superconducting electronics. Like the conventional superconductor Nb, MgB2 is a phonon-mediated superconductor, with a relatively long coherence length. These properties make the prospect of fabricating reproducible uniform Josephson junctions, the fundamental element of superconducting circuits, much more favourable for MgB2 than for high-temperature superconductors. The higher transition temperature and larger energy gap of MgB2 promise higher operating temperatures and potentially higher speeds than Nb-based integrated circuits. However, success in MgB2 Josephson junctions has been limited because of the lack of an adequate thin-film technology. Because a superconducting integrated circuit uses a multilayer of superconducting, insulating and resistive films, an in situ process in which MgB2 is formed directly on the substrate is desirable. Here we show that this can be achieved by hybrid physical-chemical vapour deposition. The epitaxially grown MgB2 films show a high transition temperature and low resistivity, comparable to the best bulk samples, and their surfaces are smooth. This advance removes a major barrier for superconducting electronics using MgB2.

405 citations

Journal ArticleDOI
TL;DR: In this paper, a component built from 304L stainless steel incrementally graded to Inconel 625 was characterized by microscopy, chemistry, phase composition, and microhardness as a function of position.

376 citations


Cited by
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08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
TL;DR: The phytochemical properties of Lithium Hexafluoroarsenate and its Derivatives are as follows: 2.2.1.
Abstract: 2.1. Solvents 4307 2.1.1. Propylene Carbonate (PC) 4308 2.1.2. Ethers 4308 2.1.3. Ethylene Carbonate (EC) 4309 2.1.4. Linear Dialkyl Carbonates 4310 2.2. Lithium Salts 4310 2.2.1. Lithium Perchlorate (LiClO4) 4311 2.2.2. Lithium Hexafluoroarsenate (LiAsF6) 4312 2.2.3. Lithium Tetrafluoroborate (LiBF4) 4312 2.2.4. Lithium Trifluoromethanesulfonate (LiTf) 4312 2.2.5. Lithium Bis(trifluoromethanesulfonyl)imide (LiIm) and Its Derivatives 4313

5,710 citations

Journal ArticleDOI
TL;DR: The concept of high entropy introduces a new path of developing advanced materials with unique properties, which cannot be achieved by the conventional micro-alloying approach based on only one dominant element as mentioned in this paper.

4,394 citations