80 research outputs found
Fine-Tuned Language Models Generate Stable Inorganic Materials as Text
We propose fine-tuning large language models for generation of stable
materials. While unorthodox, fine-tuning large language models on text-encoded
atomistic data is simple to implement yet reliable, with around 90% of sampled
structures obeying physical constraints on atom positions and charges. Using
energy above hull calculations from both learned ML potentials and
gold-standard DFT calculations, we show that our strongest model (fine-tuned
LLaMA-2 70B) can generate materials predicted to be metastable at about twice
the rate (49% vs 28%) of CDVAE, a competing diffusion model. Because of text
prompting's inherent flexibility, our models can simultaneously be used for
unconditional generation of stable material, infilling of partial structures
and text-conditional generation. Finally, we show that language models' ability
to capture key symmetries of crystal structures improves with model scale,
suggesting that the biases of pretrained LLMs are surprisingly well-suited for
atomistic data.Comment: ICLR 2024. Code available at:
https://github.com/facebookresearch/crystal-ll
GemNet-OC: Developing Graph Neural Networks for Large and Diverse Molecular Simulation Datasets
Recent years have seen the advent of molecular simulation datasets that are
orders of magnitude larger and more diverse. These new datasets differ
substantially in four aspects of complexity: 1. Chemical diversity (number of
different elements), 2. system size (number of atoms per sample), 3. dataset
size (number of data samples), and 4. domain shift (similarity of the training
and test set). Despite these large differences, benchmarks on small and narrow
datasets remain the predominant method of demonstrating progress in graph
neural networks (GNNs) for molecular simulation, likely due to cheaper training
compute requirements. This raises the question -- does GNN progress on small
and narrow datasets translate to these more complex datasets? This work
investigates this question by first developing the GemNet-OC model based on the
large Open Catalyst 2020 (OC20) dataset. GemNet-OC outperforms the previous
state-of-the-art on OC20 by 16% while reducing training time by a factor of 10.
We then compare the impact of 18 model components and hyperparameter choices on
performance in multiple datasets. We find that the resulting model would be
drastically different depending on the dataset used for making model choices.
To isolate the source of this discrepancy we study six subsets of the OC20
dataset that individually test each of the above-mentioned four dataset
aspects. We find that results on the OC-2M subset correlate well with the full
OC20 dataset while being substantially cheaper to train on. Our findings
challenge the common practice of developing GNNs solely on small datasets, but
highlight ways of achieving fast development cycles and generalizable results
via moderately-sized, representative datasets such as OC-2M and efficient
models such as GemNet-OC. Our code and pretrained model weights are
open-sourced
From Molecules to Materials: Pre-training Large Generalizable Models for Atomic Property Prediction
Foundation models have been transformational in machine learning fields such
as natural language processing and computer vision. Similar success in atomic
property prediction has been limited due to the challenges of training
effective models across multiple chemical domains. To address this, we
introduce Joint Multi-domain Pre-training (JMP), a supervised pre-training
strategy that simultaneously trains on multiple datasets from different
chemical domains, treating each dataset as a unique pre-training task within a
multi-task framework. Our combined training dataset consists of 120M
systems from OC20, OC22, ANI-1x, and Transition-1x. We evaluate performance and
generalization by fine-tuning over a diverse set of downstream tasks and
datasets including: QM9, rMD17, MatBench, QMOF, SPICE, and MD22. JMP
demonstrates an average improvement of 59% over training from scratch, and
matches or sets state-of-the-art on 34 out of 40 tasks. Our work highlights the
potential of pre-training strategies that utilize diverse data to advance
property prediction across chemical domains, especially for low-data tasks
AdsorbML: A Leap in Efficiency for Adsorption Energy Calculations using Generalizable Machine Learning Potentials
Computational catalysis is playing an increasingly significant role in the
design of catalysts across a wide range of applications. A common task for many
computational methods is the need to accurately compute the adsorption energy
for an adsorbate and a catalyst surface of interest. Traditionally, the
identification of low energy adsorbate-surface configurations relies on
heuristic methods and researcher intuition. As the desire to perform
high-throughput screening increases, it becomes challenging to use heuristics
and intuition alone. In this paper, we demonstrate machine learning potentials
can be leveraged to identify low energy adsorbate-surface configurations more
accurately and efficiently. Our algorithm provides a spectrum of trade-offs
between accuracy and efficiency, with one balanced option finding the lowest
energy configuration 87.36% of the time, while achieving a 2000x speedup in
computation. To standardize benchmarking, we introduce the Open Catalyst Dense
dataset containing nearly 1,000 diverse surfaces and 100,000 unique
configurations.Comment: 26 pages, 7 figures. Submitted to npj Computational Material
Control of self-assembly in micro- and nano-scale systems
Control of self-assembling systems at the micro- and nano-scale provides new opportunities for the engineering of novel materials in a bottom-up fashion. These systems have several challenges associated with control including high-dimensional and stochastic nonlinear dynamics, limited sensors for real-time measurements, limited actuation for control, and kinetic trapping of the system in undesirable configurations. Three main strategies for addressing these challenges are described, which include particle design (active self-assembly), open-loop control, and closed-loop (feedback) control. The strategies are illustrated using a variety of examples such as the design of patchy and Janus particles, the toggling of magnetic fields to induce the crystallization of paramagnetic colloids, and high-throughput crystallization of organic compounds in nanoliter droplets. An outlook of the future research directions and the necessary technological advancements for control of micro- and nano-scale self-assembly is provided
Sviluppo di in anticorpo monoclonale anti-Asaia (anti-Asaia monoclonal antibody)
La presente invenzione riguarda lo sviluppo di un anticorpo monoclonale prodotto contro batteri del genere Asaia. Il succitato anticorpo è caratterizzato da elevata specificità ed è stato ottenuto mediante la fusione di cellule mielomatose murine con splenociti ottenuti da topi Balb/c immunizzati con il batterio di nostro interesse, ovvero Asaia, secondo la tecnica messa a punto da Kohler e Milstein nel 1974 (Nature 256: 495-497)
Application of RELAP5/Mod3.3 - Fluent coupling codes to CIRCE-HERO
This paper presents the work ongoing at the DICI (Dipartimento di Ingegneria Civile e Industriale) of the University of Pisa on the application of coupled methodology between Fluent CFD code and RELAP5/Mod3.3 system code. In particular, this methodology was applied to the LBE-water heat exchanger HERO, with the aim to analyse the performances of this component. The test section object of this study is installed inside the vessel S100 of the CIRCE facility, built at ENEA Brasimone Research Centre. In the proposed methodology the CFD code is adopted to simulate the LBE side of the HERO heat exchanger, whereas the secondary side (two-phase flow, water-vapour) is simulated by the STH code. In this procedure, the variables exchanged between the boundaries of the two codes are: the bulk temperature and heat transfer coefficient of the ascending water (in two-phase flow) obtained from RELAP5 and transferred to Fluent code; the wall temperature at the water side surface of the pipes is calculated by Fluent and passed to RELAP5 code. The coupling procedure was verified by comparing the obtained results with the analogous ones achieved with the RELAP5 stand-alone calculation, proving that the developed coupling methodology is reliable. Further, the coupled simulation allows to obtain more accurate information on the LBE side
Application of RELAP5/Mod3.3–Fluent coupling codes to CIRCE-HERO
This paper presents the work ongoing at the DICI (Dipartimento di Ingegneria Civile e Industriale) of the University of Pisa on the application of coupled methodology between Fluent CFD code and RELAP5/Mod3.3 system code. In particular, this methodology was applied to the LBE-water heat exchanger HERO, with the aim to analyse the performances of this component. The test section object of this study is installed inside the vessel S100 of the CIRCE facility, built at ENEA Brasimone Research Centre. In the proposed methodology the CFD code is adopted to simulate the LBE side of the HERO heat exchanger, whereas the secondary side (two-phase flow, water-vapour) is simulated by the STH code. In this procedure, the variables exchanged between the boundaries of the two codes are: the bulk temperature and heat transfer coefficient of the ascending water (in two-phase flow) obtained from RELAP5 and transferred to Fluent code; the wall temperature at the water side surface of the pipes is calculated by Fluent and passed to RELAP5 code. The coupling procedure was verified by comparing the obtained results with the analogous ones achieved with the RELAP5 stand-alone calculation, proving that the developed coupling methodology is reliable. Further, the coupled simulation allows to obtain more accurate information on the LBE side
- …