This paper is dedicated to studying the following Kirchhoff-type problem
0.1
-
a
+
b
∫
R
3
|
∇
u
|
2
d
x
▵
u
+
V
(
x
)
u
=
f
(
u
)
,
x
∈
R
3
;
u
∈
H
1
(
R
3
)
,
where
a
>
0
,
b
≥
0
are two constants,
...V
(
x
) is differentiable and
f
∈
C
(
R
,
R
)
. By introducing some new tricks, we prove that the above problem admits a ground state solution of Nehari–Pohozaev type and a least energy solution under some mild assumptions on
V
and
f
. Our results generalize and improve the ones in Guo (J Differ Equ 259:2884–2902,
2015
) and Li and Ye (J Differ Equ 257:566–600,
2014
) and some other related literature.
Wave propagation in granular materials is one of the most fundamental problems in mechanics and physics, with both scientific fascination and practical importance. Whether elastic waves in granular ...media are affected by particle morphology and, if yes, how they are affected remain open questions. Here we present a novel grain-scale model to address these fundamental questions. Efficient techniques are incorporated in the model to cope with a huge number of non-spherical particles which are randomly packed to propagate elastic waves. The variability of particle shape is mathematically described using the superquadric function and a family of geometric shapes is produced so that a systematic investigation of the effect of particle shape becomes viable. The difficulty with the detection of particle contacts that are represented by nonlinear Hertzian contact law is tackled using an efficient algorithm. A marked finding from the multiple series of simulations using this new model is that: an increase in the aspect ratio of particles (i.e. particles changing from spherical to ellipsoidal) leads to a notable rise in the elastic wave velocity, for both compression and shear waves, whereas for non-spherical particles with a given aspect ratio, an increased particle blockiness causes a moderate reduction in the wave velocity. Moreover, it is found that an assembly of particles with higher aspect ratio is associated with a broader range of transmitted frequencies while an assembly of particles with magnified blockiness holds back the conduction of higher frequencies. Based on statistical analyses, we further show that the transition from spherical to non-spherical particles is associated with a broader range of void ratios and increased coordination numbers whereas inflated blockiness brings an opposite impact, and these changes are linked with the observed effect of particle shape on the characteristics of elastic waves, in both time and frequency domains.
Given a multiple-antenna source and a multiple-antenna destination, a multiple-antenna relay between the source and the destination is desirable under useful circumstances. A non-regenerative ...multiple-antenna relay, also called non-regenerative MIMO (multi-input multi-output) relay, is designed to optimize the capacity between the source and the destination. Without a direct link between the source and the destination, the optimal canonical coordinates of the relay matrix are first established, and the optimal power allocations along these coordinates are then found. The system capacity with the optimal relay matrix is shown to be significantly higher than those with heuristic relay matrices. When a direct link is present, upper and lower bounds of the optimal system capacity are discussed.
Plastic packaging for food and non-food applications is non-biodegradable, and also uses up valuable and scarce non-renewable resources like petroleum. With the current focus on exploring ...alternatives to petroleum and emphasis on reduced environmental impact, research is increasingly being directed at development of biodegradable food packaging from biopolymer-based materials. The proposed paper will present a review of recent developments in biopolymer-based food packaging materials including natural biopolymers (such as starches and proteins), synthetic biopolymers (such as poly lactic acid), biopolymer blends, and nanocomposites based on natural and synthetic biopolymers. The paper will discuss the various techniques that have been used for developing cost-effective biodegradable packaging materials with optimum mechanical strength and oxygen and moisture barrier properties. This is a timely review as there has been a recent renewed interest in research studies, both in the industry and academia, towards development of a new generation of biopolymer-based food packaging materials with possible applications in other areas.
No standard of care for mucosal melanoma (MM) in the adjuvant setting has been established. Meanwhile, relapse-free survival (RFS) is only ∼5 months after surgery alone. This phase II trial aimed to ...compare toripalimab versus high-dose interferon-α2b (HDI) as an adjuvant therapy for resected MM.
From July 2017 to May 2019, 145 patients with resected MM were randomized (1 : 1) to receive HDI (n = 72) or toripalimab (n = 73) for 1 year until disease relapse/distant metastasis, unacceptable toxicity, or withdrawal of consent. The primary endpoint was RFS. The secondary endpoints included distant metastasis-free survival (DMFS), overall survival (OS), and safety.
After a median follow-up of 26.3 months, the number of RFS, OS, and DMFS events was 51 versus 46, 33 versus 29, and 49 versus 44 in the toripalimab arm and the HDI arm, respectively. The median RFS was 13.6 95% confidence interval (CI) 8.31-19.02 months and 13.9 (95% CI 8.28-19.61) months in the toripalimab arm and the HDI arm, respectively. The DMFS was not significantly different between the two arms hazard ratio (HR) 1.00; 95% CI 0.65-1.54. The median OS was 35.1 months (95% CI 27.93 months-not reached) in the toripalimab arm, with no significant difference in all-cause death (HR 1.11, 95% CI 0.66-1.84) for the two arms. The median sums of the patients’ actual infusion doses were 3672 mg and 1054.5 MIU in the toripalimab arm and the HDI arm, respectively. The incidence of treatment-emergent adverse events with a grade ≥3 was much higher in the HDI arm than in the toripalimab arm (87.5% versus 27.4%).
Toripalimab showed a similar RFS and a more favorable safety profile than HDI, both better than historical data, suggesting that toripalimab might be the better treatment option. However, additional translational studies and better treatment regimens are still warranted to improve the clinical outcome of MM.
•This is the first study to compare toripalimab versus HDI as adjuvant therapy for resected MM.•In PD-L1-positive patients, the median RFS was ∼6 months longer in the toripalimab arm than in the HDI arm.•The incidence of TEAEs with a grade ≥3 was much higher in the HDI arm than in the toripalimab arm.•Both interventions have potential for MM; toripalimab might be the better treatment option.
Magnon dark modes and gradient memory Zhang, Xufeng; Zou, Chang-Ling; Zhu, Na ...
Nature communications,
11/2015, Letnik:
6, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Extensive efforts have been expended in developing hybrid quantum systems to overcome the short coherence time of superconducting circuits by introducing the naturally long-lived spin degree of ...freedom. Among all the possible materials, single-crystal yttrium iron garnet has shown up recently as a promising candidate for hybrid systems, and various highly coherent interactions, including strong and even ultrastrong coupling, have been demonstrated. One distinct advantage in these systems is that spins form well-defined magnon modes, which allows flexible and precise tuning. Here we demonstrate that by dissipation engineering, a non-Markovian interaction dynamics between the magnon and the microwave cavity photon can be achieved. Such a process enables us to build a magnon gradient memory to store information in the magnon dark modes, which decouple from the microwave cavity and thus preserve a long lifetime. Our findings provide a promising approach for developing long-lifetime, multimode quantum memories.
In this Letter we propose a kinematic model to explain how collisions with a surface and rotational Brownian motion give rise to accumulation of microswimmers near a surface. In this model, an ...elongated microswimmer invariably travels parallel to the surface after hitting it from an oblique angle. It then swims away from the surface, facilitated by rotational Brownian motion. Simulations based on this model reproduce the density distributions measured for the small bacteria E. coli and Caulobacter crescentus, as well as for the much larger bull spermatozoa swimming between two walls.
Single-photon counters are single-pixel binary devices that click upon the absorption of a photon but obscure its spectral information, whereas resolving the color of detected photons has been in ...critical demand for frontier astronomical observation, spectroscopic imaging and wavelength division multiplexed quantum communications. Current implementations of single-photon spectrometers either consist of bulky wavelength-scanning components or have limited detection channels, preventing parallel detection of broadband single photons with high spectral resolutions. Here, we present the first broadband chip-scale single-photon spectrometer covering both visible and infrared wavebands spanning from 600 nm to 2000 nm. The spectrometer integrates an on-chip dispersive echelle grating with a single-element propagating superconducting nanowire detector of ultraslow-velocity for mapping the dispersed photons with high spatial resolutions. The demonstrated on-chip single-photon spectrometer features small device footprint, high robustness with no moving parts and meanwhile offers more than 200 equivalent wavelength detection channels with further scalability.
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