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"Yang, Zhi"
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Quantitative assessment of groundwater and surface water interactions in the Hailiutu River Basin, Erdos Plateau, China
This study presents a multi-disciplinary approach for investigating the interactions between groundwater and surface water in the semi-arid Hailiutu catchment in the Erdos Plateau, Northwest China.
Book
Light-driven continuous rotating Möbius strip actuators
Twisted toroidal ribbons such as the one-sided Möbius strip have inspired scientists, engineers and artists for many centuries. A physical Möbius strip exhibits interesting mechanical properties deriving from a tendency to redistribute the torsional strain away from the twist region. This leads to the interesting possibility of building topological actuators with continuous deformations. Here we report on a series of corresponding bi-layered stripe actuators using a photothermally responsive liquid crystal elastomer as the fundamental polymeric material. Employing a special procedure, even Möbius strips with an odd number of twists can be fabricated exhibiting a seamless homeotropic and homogeneous morphology. Imposing a suitable contraction gradient under near-infrared light irradiation, these ribbons can realize continuous anticlockwise/clockwise in-situ rotation. Our work could pave the way for developing actuators and shape morphing materials that need not rely on switching between distinct states.
Shape morphing materials are usually difficult to operate in a continuous fashion. Nie et al. fabricate stripes with liquid crystalline elastomers that can be given a Möbius-like morphology with seamless material composition, and perpetually driven under photothermally induced actuation.
Journal Article
Optimizing Variational Quantum Algorithms Using Pontryagin’s Minimum Principle
We use Pontryagin’s minimum principle to optimize variational quantum algorithms. We show that for a fixed computation time, the optimal evolution has a bang-bang (square pulse) form, both for closed and open quantum systems with Markovian decoherence. Our findings support the choice of evolution ansatz in the recently proposed quantum approximate optimization algorithm. Focusing on the Sherrington-Kirkpatrick spin glass as an example, we find a system-size independent distribution of the duration of pulses, with characteristic time scale set by the inverse of the coupling constants in the Hamiltonian. The optimality of the bang-bang protocols and the characteristic time scale of the pulses provide an efficient parametrization of the protocol and inform the search for effective hybrid (classical and quantum) schemes for tackling combinatorial optimization problems. Furthermore, we find that the success rates of our optimal bang-bang protocols remain high even in the presence of weak external noise and coupling to a thermal bath.
Journal Article
Transverse parton distribution and fragmentation functions at NNLO: the quark case
A
bstract
We revisit the calculation of perturbative quark transverse momentum de- pendent parton distribution functions and fragmentation functions using the exponential regulator for rapidity divergences. We show that the exponential regulator provides a consistent framework for the calculation of various ingredients in transverse momentum dependent factorization. Compared to existing regulators in the literature, the exponential regulator has a couple of advantages which we explain in detail. As a result, the calcula- tion is greatly simplified and we are able to obtain the next-to-next-to-leading order results up to
O
(
E
2
) in dimensional regularization. These terms are necessary for a higher order calculation which is made possible with the simplification brought by the new regulator. As a by-product, we have obtained the two-loop quark jet function for the Energy-Energy Correlator in the back-to-back limit, which is the last missing ingredient for its N
3
LL resummation.
Journal Article
In situ probing electrified interfacial water structures at atomically flat surfaces
Solid/liquid interfaces are ubiquitous in nature and knowledge of their atomic-level structure is essential in elucidating many phenomena in chemistry, physics, materials science and Earth science1. In electrochemistry, in particular, the detailed structure of interfacial water, such as the orientation and hydrogen-bonding network in electric double layers under bias potentials, has a significant impact on the electrochemical performances of electrode materials2–4. To elucidate the structures of electric double layers at electrochemical interfaces, we combine in situ Raman spectroscopy and ab initio molecular dynamics and distinguish two structural transitions of interfacial water at electrified Au single-crystal electrode surfaces. Towards negative potentials, the interfacial water molecules evolve from structurally ‘parallel’ to ‘one-H-down’ and then to ‘two-H-down’. Concurrently, the number of hydrogen bonds in the interfacial water also undergoes two transitions. Our findings shed light on the fundamental understanding of electric double layers and electrochemical processes at the interfaces.Interfacial water structures in electric double layers under bias potentials can impact the electrochemical performance of electrodes. Two structural transitions of interfacial water at electrified Au single-crystal electrode surfaces have now been identified.
Journal Article
Nutritional status of patients with gastrointestinal cancers and analysis of factors for postoperative infections
Background
Patients with gastrointestinal cancer have a higher risk of malnutrition and postoperative infection.
Objective
To investigate the nutritional status of patients with gastrointestinal cancers and factors for postoperative infections.
Method
Based on the nutritional risk status, 294 patients with gastrointestinal tumours were divided into a nutritional risk group and a non-nutritional risk group, and the differences between the two groups were compared.
Results
Among the included patients, 128 were at preoperative nutritional risk (43.54%); there were significant differences between the two groups in terms of age (66.25 ± 11.73 vs. 58.36 ± 10.41 years,
P
< 0.001), percentage of gastric cancers (39.84% vs. 28.92%,
P
= 0.049), percentage of stage IV tumours (60.16% vs. 45.18%,
P
= 0.011), total protein (64.90 ± 6.82 vs. 67.21 ± 7.41 g/L,
P
= 0.007), albumin (38.32 ± 4.74 vs. 41.61 ± 5.10 g/L,
P
< 0.001) and haemoglobin (112.72 ± 22.63 vs. 125.11 ± 22.79 g/L,
P
< 0.001). Multivariate logistic regression analysis showed that risk factors for postoperative infections in patients included age ≥ 60 years (odds ratio [OR] = 2.266 95%CI = 1.357–4.134), Nutrition Risk Screening (NRS)-2002 score ≥ 3 (OR = 2.183, 95%CI = 1.218–4.102), alcohol history (OR = 2.505, 95%CI = 1.370–4.683), comorbid diabetes mellitus (OR = 2.110, 95%CI = 1.381–4.023) and surgical time ≥ 6 h (OR = 2.446, 95%CI = 1.359–4.758).
Conclusion
Patients with gastrointestinal cancers are at high incidence of preoperative nutritional risk, and those with an NRS-2002 score of > 3, history of alcohol consumption and surgical time of > 6 h have a higher risk of postoperative infections.
Journal Article