1,204 research outputs found
Phase transitions and thermodynamics of the two-dimensional Ising model on a distorted Kagom\'{e} lattice
The two-dimensional Ising model on a distorted Kagom\'{e} lattice is studied
by means of exact solutions and the tensor renormalisation group (TRG) method.
The zero-field phase diagrams are obtained, where three phases such as
ferromagnetic, ferrimagnetic and paramagnetic phases, along with the
second-order phase transitions, have been identified. The TRG results are quite
accurate and reliable in comparison to the exact solutions. In a magnetic
field, the magnetization (), susceptibility and specific heat are studied by
the TRG algorithm, where the plateaux are observed in the magnetization
curves for some couplings. The experimental data of susceptibility for the
complex Co(N)(bpg) DMF are fitted with the TRG results,
giving the couplings of the complex and
Emergent spin-1 trimerized valence bond crystal in the spin-1/2 Heisenberg model on the star lattice
We explore the frustrated spin- Heisenberg model on the star lattice
with antiferromagnetic (AF) couplings inside each triangle and ferromagnetic
(FM) inter-triangle couplings (), and calculate its magnetic and
thermodynamic properties. We show that the FM couplings do not sabotage the
magnetic disordering of the ground state due to the frustration from the AF
interactions inside each triangle, but trigger a fully gapped
inversion-symmetry-breaking trimerized valence bond crystal (TVBC) with
emergent spin-1 degrees of freedom. We discover that with strengthening ,
the system scales exponentially, either with or without a magnetic field :
the order parameter, the five critical fields that separate the -
ground-state phase diagram into six phases, and the excitation gap obtained by
low-temperature specific heat, all depend exponentially on . We calculate
the temperature dependence of the specific heat, which can be directly compared
with future experiments.Comment: 7 pages, 6 figure
Linearized Tensor Renormalization Group Algorithm for Thermodynamics of Quantum Lattice Models
A linearized tensor renormalization group (LTRG) algorithm is proposed to
calculate the thermodynamic properties of one-dimensional quantum lattice
models, that is incorporated with the infinite time-evolving block decimation
technique, and allows for treating directly the two-dimensional transfer-matrix
tensor network. To illustrate its feasibility, the thermodynamic quantities of
the quantum XY spin chain are calculated accurately by the LTRG, and the
precision is shown to be comparable with (even better than) the transfer matrix
renormalization group (TMRG) method. Unlike the TMRG scheme that can only deal
with the infinite chains, the present LTRG algorithm could treat both finite
and infinite systems, and may be readily extended to boson and fermion quantum
lattice models.Comment: published versio
Combining regenerated gratings and optical fibre Fabry-Pérot cavities for dual sensing of ultra-high temperature and strain
© 2015 Copyright SPIE. The successful regeneration of fibre Bragg gratings (FBGs) inscribed in an inline fibre etalon is demonstrated. The etalon is formed by UV-micromaching of the fibre end-face to form a cylindrical hole, the fibre is then fusion spliced to seal the cavity. Such a fibre device has excellent potential for the simultaneous measurement of ultra-high temperatures and strain
Implementation of an integrated continuous downstream process for a monoclonal antibody production
The biopharmaceutical market is driving the revolution from batch to continuous manufacturing (CM) for higher productivity and lower cost. In this work, a bench-scale fully integrated continuous downstream process for monoclonal antibody production was established and successfully scaled up to 200 L scale. The process includes a continuous proteinA step, a viral inactivation step, a batch-wise cation exchange and anion exchange step, a batch-wise viral-filtration step, and a single-pass UF/DF step. An inline protein quantity monitoring system was designed to control protein loading mass on cation exchange column. All the steps were connected through surge tanks and integrated by DeltaVTM automatic control system.
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SMART: A Situation Model for Algebra Story Problems via Attributed Grammar
Solving algebra story problems remains a challenging task in artificial
intelligence, which requires a detailed understanding of real-world situations
and a strong mathematical reasoning capability. Previous neural solvers of math
word problems directly translate problem texts into equations, lacking an
explicit interpretation of the situations, and often fail to handle more
sophisticated situations. To address such limits of neural solvers, we
introduce the concept of a \emph{situation model}, which originates from
psychology studies to represent the mental states of humans in problem-solving,
and propose \emph{SMART}, which adopts attributed grammar as the representation
of situation models for algebra story problems. Specifically, we first train an
information extraction module to extract nodes, attributes, and relations from
problem texts and then generate a parse graph based on a pre-defined attributed
grammar. An iterative learning strategy is also proposed to improve the
performance of SMART further. To rigorously study this task, we carefully
curate a new dataset named \emph{ASP6.6k}. Experimental results on ASP6.6k show
that the proposed model outperforms all previous neural solvers by a large
margin while preserving much better interpretability. To test these models'
generalization capability, we also design an out-of-distribution (OOD)
evaluation, in which problems are more complex than those in the training set.
Our model exceeds state-of-the-art models by 17\% in the OOD evaluation,
demonstrating its superior generalization ability
LEMMA: Learning Language-Conditioned Multi-Robot Manipulation
Complex manipulation tasks often require robots with complementary
capabilities to collaborate. We introduce a benchmark for LanguagE-Conditioned
Multi-robot MAnipulation (LEMMA) focused on task allocation and long-horizon
object manipulation based on human language instructions in a tabletop setting.
LEMMA features 8 types of procedurally generated tasks with varying degree of
complexity, some of which require the robots to use tools and pass tools to
each other. For each task, we provide 800 expert demonstrations and human
instructions for training and evaluations. LEMMA poses greater challenges
compared to existing benchmarks, as it requires the system to identify each
manipulator's limitations and assign sub-tasks accordingly while also handling
strong temporal dependencies in each task. To address these challenges, we
propose a modular hierarchical planning approach as a baseline. Our results
highlight the potential of LEMMA for developing future language-conditioned
multi-robot systems.Comment: 8 pages, 3 figure
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