A (2+1)-dimensional extended Calogero–Bogoyavlenskii–Schiff system in nonlinear optics, fluid dynamics and plasma physics is investigated via the symbolic computation in this paper. Soliton ...solutions, which are kink-shaped, are obtained via the Hirota method. Breather solutions are derived via the extended homoclinic test approach, and lump solutions are obtained from the breather solutions under a limiting procedure. We find that the shape and amplitude of the one soliton keep unchanged during the propagation, and the velocity of one soliton depends on all the coefficients in the system. We graphically demonstrate that the interaction between the two solitons is elastic, and analyse the solitons with the influence of the coefficients. We observe that the amplitudes and shapes of the breather and lump remain unchanged during the propagation, and graphically present the breathers and lumps with the influence of the coefficients.
It is frequently observed that overparameterized neural networks generalize well. Regarding such phenomena, existing theoretical work mainly devotes to linear settings or fully-connected neural ...networks. This paper studies the learning ability of an important family of deep neural networks, deep convolutional neural networks (DCNNs), under both underparameterized and overparameterized settings. We establish the first learning rates of underparameterized DCNNs without parameter or function variable structure restrictions presented in the literature. We also show that by adding well-defined layers to a non-interpolating DCNN, we can obtain some interpolating DCNNs that maintain the good learning rates of the non-interpolating DCNN. This result is achieved by a novel network deepening scheme designed for DCNNs. Our work provides theoretical verification of how overfitted DCNNs generalize well.
This paper attempts to reveal the atmospheric water vapor transports associated with typical anomalous summer rainfall patterns in China. The results show that origins of water vapor supply related ...to anomalous rainfall patterns are different from those related to the normal monsoon rainfall. Anomalous pattern 1, with a heavier rainbelt along the middle and lower reaches of the Yangtze River valley, follows from a convergence of the tropical southwest water vapor transport with the midlatitude northeast water vapor transport; the tropical water vapor transport comes directly from the Bay of Bengal and the South China Sea but originally from the Philippine Sea. The anomalous water vapor transport is associated with a southwestward extension of the western Pacific subtropical high and a southward shift of the upper East Asian jet stream. Anomalous pattern 2, with a main rainbelt along the Huaihe River valley, is supported by the convergence of the subtropical southwest water vapor with the midlatitude water vapor transport. The subtropical branch comes directly from the South China Sea but originally from the East China Sea and the adjacent subtropical Pacific to the further east along 20–25°N. The background large‐scale circulation change includes a northwestward extension of the western Pacific subtropical high and an eastward shift of the upper jet stream. Although the cross‐equator flows including the Somali jet supply abundant water vapor for the normal condition of June, July, and August rainfall over China, the tropical water vapor transports related to typical anomalous rainfall anomalies originate from the tropical western Pacific Ocean. The northward transport of anomalous warm water vapor occurs mainly in the lower troposphere, while the transport of midlatitude cold water vapor occurs briefly in the upper troposphere.
Mesenchymal stromal cells (MSCs), also known as mesenchymal stem cells, have been intensely investigated for clinical applications within the last decades. However, the majority of registered ...clinical trials applying MSC therapy for diverse human diseases have fallen short of expectations, despite the encouraging pre-clinical outcomes in varied animal disease models. This can be attributable to inconsistent criteria for MSCs identity across studies and their inherited heterogeneity. Nowadays, with the emergence of advanced biological techniques and substantial improvements in bio-engineered materials, strategies have been developed to overcome clinical challenges in MSC application. Here in this review, we will discuss the major challenges of MSC therapies in clinical application, the factors impacting the diversity of MSCs, the potential approaches that modify MSC products with the highest therapeutic potential, and finally the usage of MSCs for COVID-19 pandemic disease.
A few scholars have developed the models for retrieval of water depth from subsurface reflectance of multispectral images to avoid the influences of such as sun glitter. However, the models are only ...suitable for case I water. For this reason, this study proposes a bathymetry retrieval model using subsurface reflectance for both case I and case II water. The model first corrects the water surface reflectance image and then converts it into a subsurface reflectance image, and the subsurface reflectance image is used as the water depth retrieval image. Landsat 8 images were taken for experiments in case 1 water and case 2 water, and two water areas, Weizhou Island, Guangxi, China, and Molokai Island, Hawaii, USA, were used to verify the proposed model. The experimental results showed that the proposed model reduced the root mean squared error (RMSE) of the retrieved water depth in the Weizhou and Molokai areas from 3.113 m to 2.903 m and 4.239 m to 3.653 m, respectively, i.e., improve accuracy of water depth at 6.75% and 13.82% for Weizhou and Molokai areas, respectively. Therefore, the results demonstrate that the proposed model using subsurface reflectance can significantly improve the accuracy of bathymetry retrieval via spaceborne multispectral images.
The topology of a covalent organic framework (COF) is generally believed to be dictated by the symmetries of the monomers used for the condensation reaction. In this context, the use of monomers with ...different symmetries is usually required to afford COFs with different topologies. Herein, we report a conceptual strategy to regulate the topology of 2D COFs by introducing alkyl substituents into the skeleton of a parent monomer. The resulting monomers, sharing the same
symmetry, were assembled with a
symmetric tetraamine to generate a dual-pore COF or single-pore COFs, depending on the sizes of the substituents, which were evidenced using PXRD studies and pore size distribution analyses. These results demonstrate that the substituent is able to exert a significant influence on the topology of COFs, which is crucial for their application.
Self-assembly has emerged as a powerful approach to generating complex supramolecular architectures. Despite there being many crystalline frameworks reported in the solid state, the construction of ...highly soluble periodic supramolecular networks in a three-dimensional space is still a challenge. Here we demonstrate that the encapsulation motif, which involves the dimerization of two aromatic units within cucurbit8uril, can be used to direct the co-assembly of a tetratopic molecular block and cucurbit8uril into a periodic three-dimensional supramolecular organic framework in water. The periodicity of the supramolecular organic framework is supported by solution-phase small-angle X-ray-scattering and diffraction experiments. Upon evaporating the solvent, the periodicity of the framework is maintained in porous microcrystals. As a supramolecular 'ion sponge', the framework can absorb different kinds of anionic guests, including drugs, in both water and microcrystals, and drugs absorbed in microcrystals can be released to water with selectivity.
Summary
A fin‐enhanced phase change material (PCM) system was introduced for cylindrical lithium‐ion batteries. Experiments were performed to explore the performance of the systems during ...discharging. The working time of the PCM‐Fin system is improved by 75%, 68%, and 61% compared to that of the system without fins under the heat production rate of 10, 12.5, and 15 W, accordingly. Simulations were performed by ANSYS Fluent to explore the influence of the geometric parameters (thickness, length, and number) and materials (nylon, titanium, steel, Al alloy, and copper) of the fins on the thermal performance. A function considering both the improvement in thermal performance and the increase in system weight was defined to assess the overall performance. Results indicate that fins made of Al alloy with the number of 8, a length of 7.5 mm, and a thickness of 0.5 mm give the best performance. Besides, the working time of the PCM‐Fin system is 2150, 2490, 2940, and 3570 seconds for the coefficient of heat transfer of 5, 10, 15, and 20 W m−2 K−1, respectively, which is increased by 14%, 32%, 56%, and 90%, compared to that of the adiabatic condition, demonstrating the effectiveness of the PCM‐Fin system.
A fin‐enhanced phase change material (PCM) system is proposed for the battery thermal management. The safe working time of the fin‐enhanced system is found to be approximately 1.61–1.75 times as that of the PCM system. Numerical results demonstrate that the added fins form a network for thermal conduction within the PCM, which enhances the heat dissipation rate considerably.
Aerosol acidity plays an important role in atmospheric chemistry. China emits large amounts of SO2, NOx, and NH3 into the atmosphere, but aerosol acidity is poorly characterized. In this study, ...simultaneous 1 h measurements of particulate and gaseous compositions along with the ISORROPIA‐II thermodynamic equilibrium model were used to study aerosol acidity during severe haze episodes in northern China. The summed concentration of sulfate, nitrate, and ammonium was 135 ± 51 μg/m3 with a maximum of 250 μg/m3, and the gas‐phase NH3 mixing ratio was 22 ± 9 ppb. Fine particles were moderately acidic, with a pH range of 3.0–4.9 and an average of 4.2, which was higher than those in the United States and Europe. Excess NH3 and high aerosol water content are responsible for the relatively lower aerosol acidity. These results suggest that the new pathways for sulfate production in China proposed by recent studies should be revisited.
Key Points
Aerosol acidity plays an important role in atmospheric chemistry but poorly characterized in northern China with significant gaseous emissions
Fine particles were moderately acidic during severe haze episodes in northern China, with its pH ranging from 3.0 to 4.9 and on average 4.2
Excess ammonia and abundant aerosol water content lead to relatively lower aerosol acidity in northern China compared to those in United States and Europe
Adenosine triphosphate (ATP) is amphiphilic in nature and has the characteristics of a hydrotrope because of the charged triphosphate moiety and the large aromatic ring located on each end of its ...structure. Previous studies revealed that ATP can effectively maintain the solubility and prevent liquid-liquid phase separation (LLPS) of some biological proteins. In this study, we assessed the impact of ATP on the stability of a model therapeutic IgG1 antibody (MA1) to evaluate its potential application in protein formulation design. In our system, ATP promotes rapid LLPS of MA1 and we demonstrate that the ATP-MA1 static interaction drives phase separation of MA1. The attractive protein-protein interaction increased exclusively in the presence of ATP but not in the presence of other ATP analogues, such as adenosine diphosphate, adenosine monophosphate, and adenine. Through an intrinsic fluorescence quenching study, we revealed that ATP bound to MA1 electrostatically and formed static interactions; furthermore, such static ATP-MA1 interactions significantly altered the surface property of the protein and the protein-protein interactions and subsequently induced LLPS of MA1. This ATP-induced LLPS could be effectively eliminated by Mg
, which chelated with ATP and thus negated ATP-MA1 static interaction. Our results revealed the unique molecular mechanism of ATP-induced rapid LLPS of MA1.
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