Existing research on the security of the supply of critical materials for clean energy generally aggregates information at the country level, a practice that obscures the extensive role of foreign... Show moreExisting research on the security of the supply of critical materials for clean energy generally aggregates information at the country level, a practice that obscures the extensive role of foreign direct investment (FDI) in the production of critical materials. FDI refers to an ownership stake in a company or project by an overseas investor. Here we establish a database for global mining of lithium, cobalt, nickel and platinum at company level, covering 240 countries and regions. We show that 47% of lithium, 71% of cobalt, 41% of nickel and 34% of platinum mined in 2019 were under FDI. We then explore how FDI may affect supply risks by proposing a supply risk index that allocates production of the critical materials to the country of origin of investors instead of the country where production is located. We present upper and lower bounds of the supply risk index that reflect scenarios where either all investors or only state investors prioritize the home-country demand, respectively. This study presents an approach for assessing the national supply risks of critical materials, considering the geographical allocation of FDI. Show less
Cine and 4D flow cardiac MRI are two important non-invasive MR imaging techniques to assess cardiac function and diagnose cardiovascular diseases. Cine MRI offers great soft tissue detail which... Show moreCine and 4D flow cardiac MRI are two important non-invasive MR imaging techniques to assess cardiac function and diagnose cardiovascular diseases. Cine MRI offers great soft tissue detail which allows clinical experts to evaluate structure and function of the heart. 4D flow MRI further has the ability of three-dimensional time-resolved acquisition of blood flow velocity, which can be used to derive intra-cardiac hemodynamic parameters. In this thesis, we developed deep learning-based approaches to analyze cine and 4D flow cardiac MRI. This thesis proposes deep learning based methods for quantifying cardiac MRI. The described methods can be applied for cine MR image quality classification and ventricle segmentation without any human interactions. Investigating combining and fusing magnitude and velocity images can be helpful for left ventricle segmentation in 4D flow MRI, which is not fully explored yet. Moreover, we proposed a network to predict the blood flow pattern from the cine MRI. By combining visualization of the blood flow and myocardial motion in the routinely acquired standard CMR exams, the method can be potentially used in clinical studies. Show less
We have studied the palladium-mediated activation of C(sp(n))-X bonds (n = 1-3 and X = H, CH3, Cl) in archetypal model substrates H3C-CH2-X, H2C=CH-X and HC equivalent to C-X by catalysts PdLn with... Show moreWe have studied the palladium-mediated activation of C(sp(n))-X bonds (n = 1-3 and X = H, CH3, Cl) in archetypal model substrates H3C-CH2-X, H2C=CH-X and HC equivalent to C-X by catalysts PdLn with L-n = no ligand, Cl-, and (PH3)(2), using relativistic density functional theory at ZORA-BLYP/TZ2P. The oxidative addition barrier decreases along this series, even though the strength of the bonds increases going from C(sp(3))-X, to C(sp(2))-X, to C(sp)-X. Activation strain and matching energy decomposition analyses reveal that the decreased oxidative addition barrier going from sp(3), to sp(2), to sp, originates from a reduction in the destabilizing steric (Pauli) repulsion between catalyst and substrate. This is the direct consequence of the decreasing coordination number of the carbon atom in C(sp(n))-X, which goes from four, to three, to two along this series. The associated net stabilization of the catalyst-substrate interaction dominates the trend in strain energy which indeed becomes more destabilizing along this same series as the bond becomes stronger from C(sp(3))-X to C(sp)-X. Show less
In Altmetrics, tweets are considered as important potential indicators of immediate social impact of scholarly articles. However, it is still unclear to what extent Twitter captures the actual... Show moreIn Altmetrics, tweets are considered as important potential indicators of immediate social impact of scholarly articles. However, it is still unclear to what extent Twitter captures the actual scholarly impact. Therefore, it is necessary to investigate the people who cite the articles and the content of the tweets with attitude towards the articles comprehensively. In this paper, we combine different indicators to identify opinion leaders in the spread of the articles, and use sentimental analysis to quantify the sentimental polarity of tweets. Altmetrics should highlight the positive role of scientific research results to the public, which is more valuable than simple numbers. Show less
In contrast to cobalt, reaction of ligand L1 SSL1 with [Fe(MeCN)6](BF4)2 did not yield the expected Fe(III) thiolate compound. This work is an unprecedented example of redox interconversion between... Show moreIn contrast to cobalt, reaction of ligand L1 SSL1 with [Fe(MeCN)6](BF4)2 did not yield the expected Fe(III) thiolate compound. This work is an unprecedented example of redox interconversion between a high-spin Co(II) disulfide compound and a low-spin Co(III) thiolate compound triggered by the nature of the anion. Show less
