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result(s) for
"Chen, Qun"
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Ocean wave energy harvesting with high energy density and self-powered monitoring system
2024
Constructing a ocean Internet of Things requires an essential ocean environment monitoring system. However, the widely distributed existing ocean monitoring sensors make it impractical to provide power and transmit monitored information through cables. Therefore, ocean environment monitoring systems particularly need a continuous power supply and wireless transmission capability for monitoring information. Consequently, a high-strength, environmentally multi-compatible, floatable metamaterial energy harvesting device has been designed through integrated dynamic matching optimization of materials, structures, and signal transmission. The self-powered monitoring system breaks through the limitations of cables and batteries in the ultra-low-frequency wave environment (1 to 2 Hz), enabling real-time monitoring of various ocean parameters and wirelessly transmitting the data to the cloud for post-processing. Compared with solar and wind energy in the ocean environment, the energy harvesting device based on the defective state characteristics of metamaterials achieves a high-energy density (99 W/m
3
). For the first time, a stable power supply for the monitoring system has been realized in various weather conditions (24 h).
Point-defect metamaterials have the property of concentrating vibration energy at the defect location. We design an environmental monitoring node based on this property, which can efficiently convert wave kinetic energy into electrical energy for real-time monitoring of the ocean environment.
Journal Article
An Optimization Model for the Selection of Bus-Only Lanes in a City
2015
The planning of urban bus-only lane networks is an important measure to improve bus service and bus priority. To determine the effective arrangement of bus-only lanes, a bi-level programming model for urban bus lane layout is developed in this study that considers accessibility and budget constraints. The goal of the upper-level model is to minimize the total travel time, and the lower-level model is a capacity-constrained traffic assignment model that describes the passenger flow assignment on bus lines, in which the priority sequence of the transfer times is reflected in the passengers' route-choice behaviors. Using the proposed bi-level programming model, optimal bus lines are selected from a set of candidate bus lines; thus, the corresponding bus lane network on which the selected bus lines run is determined. The solution method using a genetic algorithm in the bi-level programming model is developed, and two numerical examples are investigated to demonstrate the efficacy of the proposed model.
Journal Article
Orbital-dependent electron correlation in double-layer nickelate La3Ni2O7
2024
The latest discovery of high temperature superconductivity near 80 K in La
3
Ni
2
O
7
under high pressure has attracted much attention. Many proposals are put forth to understand the origin of superconductivity. The determination of electronic structures is a prerequisite to establish theories to understand superconductivity in nickelates but is still lacking. Here we report our direct measurement of the electronic structures of La
3
Ni
2
O
7
by high-resolution angle-resolved photoemission spectroscopy. The Fermi surface and band structures of La
3
Ni
2
O
7
are observed and compared with the band structure calculations. Strong electron correlations are revealed which are orbital- and momentum-dependent. A flat band is formed from the Ni-3d
z
2
orbitals around the zone corner which is ~ 50 meV below the Fermi level and exhibits the strongest electron correlation. In many theoretical proposals, this band is expected to play the dominant role in generating superconductivity in La
3
Ni
2
O
7
. Our observations provide key experimental information to understand the electronic structure and origin of high temperature superconductivity in La
3
Ni
2
O
7
.
Recently, superconductivity near 80 K was observed in La3Ni2O7 under high pressure, but the mechanism is debated. Here the authors report angle-resolved photoemission spectroscopy measurements under ambient pressure, revealing flat bands with strong electronic correlations that could be linked to superconductivity.
Journal Article
Structural transition, electric transport, and electronic structures in the compressed trilayer nickelate La4Ni3O10
by
Chen, Junfeng
,
Li, Jingyuan
,
Sun, Hualei
in
Astronomy
,
Atomic structure
,
Band structure of solids
2024
Atomic structure and electronic band structure are fundamental properties for understanding the mechanism of superconductivity. Motivated by the discovery of pressure-induced high-temperature superconductivity at 80 K in the bilayer Rud-dlesden-Popper nickelate La
3
Ni
2
O
7
, the atomic structure and electronic band structure of the trilayer nickelate La
4
Ni
3
O
10
under pressure up to 44.3 GPa are investigated. A structural transition from the monoclinic
P
2
1
/
a
space group to the tetragonal
I
4/
mmm
around 12.6–13.4 GPa is identified, accompanied by a drop of resistance below 7 K. Density functional theory calculations suggest that the bonding state of Ni
3
d
z
2
orbital rises and crosses the Fermi level at high pressures, which may give rise to possible superconductivity observed in resistance under pressure in La
4
Ni
3
O
10
. The trilayer nickelate La
4
Ni
3
O
10
shows some similarities with the bilayer La
3
Ni
2
O
7
and has unique properties, providing a new platform to investigate the underlying mechanism of superconductivity in nickelates.
Journal Article
Vibration suppression of an elastic beam with boundary inerter-enhanced nonlinear energy sinks
by
Zhang, Ye-Wei
,
Ding, Hu
,
Chen, Li-Qun
in
Bending vibration
,
Boundary conditions
,
Boundary damping
2021
Nonlinear vibration absorbers have been widely used for vibration suppression of elastic structures, but they were usually placed within the structures. However, designing such a vibration damping device within an engineering structure is possibly difficult. In this paper, an inertial nonlinear energy sinks (NES) is mounted on the boundaries of the elastic beam to suppress its vibration. Although this vibration suppression approach is more in line with engineering requirements, it introduces nonlinear oscillators at boundaries. This brings certain difficulties to the structural vibration analysis and the optimal absorber design. An approximate analytical approach for the steady-state response is developed in this work and verified by numerical solutions. The comparison with the uncontrolled system demonstrates the high-efficiency vibration suppression of the inertial NES installed on the boundary. Besides, the optimization of the NES parameters is performed. Resonance amplitude of the elastic structure can be reduced by 98% with the optimized NES. In summary, this paper proposes a novel approach to suppress the bending vibration of elastic structures through boundary NESs. The vibration reduction effect is very significant, and it is more feasible to implement. Therefore, this work is helpful to study the vibration of elastic structures with nonlinear boundaries and to promote the application of nonlinear vibration absorbers.Graphic abstractA boundary damping strategy is proposed to solve the problem of the difficulty of installing the vibration absorber in engineering. Introduce an inertial nonlinear energy sinks (NES) to reduce the weight of the shock absorber. The nonlinear boundary is separated and merged into the elastic beam vibration control equation to realize the decoupling of the continuum model. Resonance peak of the elastic structure can be reduced by 98% with the optimized NES. This work is helpful to study the vibration of elastic structures with nonlinear boundaries and to promote the application of nonlinear vibration absorbers.
Journal Article
Tracing the origin and evolutionary history of plant nucleotide-binding site–leucine-rich repeat (NBS-LRR) genes
2012
Plant disease resistance genes (R genes) encode proteins that function to monitor signals indicating pathogenic infection, thus playing a critical role in the plant's defense system. Although many studies have been performed to explore the functional details of these important genes, their origin and evolutionary history remain unclear.
In this study, focusing on the largest group of R genes, the nucleotide-binding site–leucinerich repeat (NBS-LRR) genes, we conducted an extensive genome-wide survey of 38 representative model organisms and obtained insights into the evolutionary stage and timing of NBS-LRR genes.
Our data show that the two major domains, NBS and LRR, existed before the split of prokaryotes and eukaryotes but their fusion was observed only in land plant lineages. The Toll/interleukin-1 receptor (TIR) class of NBS-LRR genes probably had an earlier origin than its nonTIR counterpart. The similarities of the innate immune systems of plants and animals are likely to have been shaped by convergent evolution after their independent origins.
Our findings start to unravel the evolutionary history of these important genes from the perspective of comparative genomics and also highlight the important role of reorganizing pre-existing building blocks in generating evolutionary novelties.
Journal Article
Effects of alternate-day fasting on body weight and dyslipidaemia in patients with non-alcoholic fatty liver disease: a randomised controlled trial
2019
Background
Alternate-day fasting (ADF) is a novel diet therapy that may achieve reduction in body weight and improvement of dyslipidaemia, but the impact of this diet on patients with non-alcoholic fatty liver disease (NAFLD) remains unknown. The aim of this study was to evaluate the effects of ADF on the body weight and lipid profile of individuals with NAFLD.
Methods
NAFLD patients (
n
= 271) were randomised to the ADF group, time-restricted feeding (TRF) group, or the control group and subjected to the respective diet for 12 weeks. Anthropometric measurements (body weight, fat mass/fat-free mass) were performed, and plasma lipids were analysed enzymatically.
Results
Within 4 weeks, the body weight decreased significantly (
P
< 0.001) in the ADF group by 4.56 ± 0.41 kg (6.1 ± 0.5%) and the TRF group by 3.62 ± 0.65 kg (4.83 ± 0.9%) compared to the control group, and it decreased even more after 12 weeks in both groups (ADF: − 4.04 ± 0.54 kg, 5.4 ± 0.7%; TRF: − 3.25 ± 0.67 kg, 4.3 ± 0.9%). Fat mass was significantly reduced by ADF (− 3.49 ± 0.37 kg; 11 ± 1.2%) and TRF (− 2.91 ± 0.41 kg; 9.6 ± 1.3%), with ADF leading to a further reduction in fat mass after 12 weeks (− 3.48 ± 0.38 kg; 11 ± 1.2%). Total cholesterol was significantly decreased at both time points in the ADF group (− 0.91 ± 0.07 mmol/L; 18.5 ± 1.5%) compared to the control and TRF groups. Both ADF (− 0.64 ± 0.06 mmol/L; 25 ± 1.9%) and TRF (0.58 ± 0.07 mmol/L; 20 ± 1.7%) achieved a significant reduction in serum triglycerides (
P
< 0.001) after 12 weeks. Changes in fat free mass, HDL, LDL, fasting insulin, glucose, liver stiffness, and systolic or diastolic blood pressure did not differ between the groups.
Conclusions
ADF appears to be an effective diet therapy for individuals with NAFLD that can achieve weight loss and improvement of dyslipidaemia within a relatively short period of time (4 to 12 weeks). Potential preventive effects of ADF on cardiovascular disease need to be confirmed by future investigations.
Trial registration
ChiCTR1900024411
, this trial was retrospectively registered on July 10, 2019.
Journal Article
Complex dynamics of a harmonically excited structure coupled with a nonlinear energy sink
2017
Nonlinear behaviors are investigated for a structure coupled with a nonlinear energy sink. The structure is linear and subject to a harmonic excitation, modeled as a forced single-degree-of-freedom oscillator. The nonlinear energy sink is modeled as an oscillator consisting of a mass, a nonlinear spring, and a linear damper. Based on the numerical solutions, global bifurcation diagrams are presented to reveal the coexistence of periodic and chaotic motions for varying nonlinear energy sink mass and stiffness. Chaos is numerically identified via phase trajectories, power spectra, and Poincaré maps. Amplitude-frequency response curves are predicted by the method of harmonic balance for periodic steady-state responses. Their stabilities are analyzed. The Hopf bifurcation and the saddle-node bifurcation are determined. The investigation demonstrates that a nonlinear energy sink may create dynamic complexity.
Journal Article
A four-DNA methylation biomarker is a superior predictor of survival of patients with cutaneous melanoma
2019
Cutaneous melanoma (CM) is a life-threatening form of skin cancer. Prognostic biomarkers can reliably stratify patients at initial melanoma diagnosis according to risk, and may inform clinical decisions. Here, we performed a retrospective, cohort-based study analyzing genome-wide DNA methylation of 461 patients with CM from the TCGA database. Cox regression analyses were conducted to establish a four-DNA methylation signature that was significantly associated with the overall survival (OS) of patients with CM, and that was validated in an independent cohort. Corresponding Kaplan–Meier analysis displayed a distinct separation in OS. The ROC analysis confirmed that the predictive signature performed well. Notably, this signature exhibited much higher predictive accuracy in comparison with known biomarkers. This signature was significantly correlated with immune checkpoint blockade (ICB) immunotherapy-related signatures, and may have potential as a guide for measures of responsiveness to ICB immunotherapy.
Journal Article
Targeting lactylation and the STAT3/CCL2 axis to overcome immunotherapy resistance in pancreatic ductal adenocarcinoma
2025
Metabolic reprogramming in pancreatic ductal adenocarcinoma (PDAC) fosters an immunosuppressive tumor microenvironment (TME) characterized by elevated lactate levels, which contribute to immune evasion and therapeutic resistance. In this issue of the JCI , Sun, Zhang, and colleagues identified nonhistone ENSA-K63 lactylation as a critical regulator that inactivates PP2A, activates STAT3/CCL2 signaling, recruits tumor-associated macrophages (TAMs), and suppresses cytotoxic T cell activity. Targeting ENSA-K63 lactylation or CCL2/CCR2 signaling reprograms the TME and enhances the efficacy of immune checkpoint blockade (ICB) in PDAC preclinical models. This work provides critical insights into the metabolic-immune crosstalk in PDAC and highlights promising therapeutic strategies for overcoming immune resistance and improving patient outcomes.
Journal Article