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In this article, the authors consider the commutators of strongly singular Calderón-Zygmund operator with Lipschitz functions. A sufficient condition is given for the boundedness of the commutators from Lebesgue spaces Lp(Rn){L}^{p}\left({{\mathbb{R}}}^{n}) to certain Campanato spaces Cp,β(Rn){C}^{p,\beta }\left({{\mathbb{R}}}^{n}).

【Objective】 Drought is an abiotic stress affecting agricultural production in almost every country across the world. Understanding its spatiotemporal variation is essential to improving water management under climate change. The purpose of this paper to analyze the variation in droughts in the main catchments over the past 60 years (1960—2019) across China. 【Method】 The standardized precipitation evapotranspiration index (SPEI) was used as the drought index; the extreme-point symmetric mode decomposition (ESMD) method was used to decompose the periods and trend of the SPEI time series, from which we calculated the spatiotemporal variation in drought. 【Result】 ①The temporal changes in drought varied with sub-basins from 1960 to 2019, and the most noticeable drought increase occurred in the continental river basins, with the SPEI linear tendency rate being -0.192/10 a. ②The ESMD results showed that the drought had been in increase across China, with the first and second periodic cycles being 2.07 years and 5 years respectively. ③The average occurring frequency of mild drought, moderate drought, severe drought, extreme drought and drought was 13.5%, 10.4%, 5.5%, 2.3% and 31.8%, with their associated average intensity being 0.74, 1.23, 1.67, 1.86 and 1.18, respectively. ④ENSO was closely related to drought, while NAO did not show significant impact on drought. 【Conclusion】 Except for southeastern China, basins in other regions have seen an increase in droughts over the past 60 years.

We aimed to evaluate the effects of lactoferrin (LF) on the osteogenic differentiation and related gene expressions of mouse embryonic osteoblast precursor cells MC3T3-E1 under mechanical strain. MC3T3-E1 cells were randomly divided into control, strain loading, LF and strain loading + LF groups. Alkaline phosphatase (ALP) activity was measured. Cytoskeletal morphology was measured by rhodamine-phalloidin staining. Formation of mineralized nodules was observed by alizarin red staining. The expressions of differentiation-related genes type I collagen (COL-1), interleukin-6 (IL-6) and osteocalcin (OCN) were determined by RT-PCR, and those of p-Runx2 and p-ERK1/2 proteins were detected by Western blotting. The number of ALP positive cells and expressions of OCN, COL-1 and IL-6 were significantly elevated (P

The mechanism of aerosol pollution transport remains highly elusive owing to the myriad of influential factors. In this study, ground station data, satellite data, ground-based LiDAR remote sensing data, sounding data, ERA5 reanalysis and a backward trajectory model were combined to investigate the formation process and optical properties of winter aerosol pollution in Beijing and surrounding areas. The analysis of ground station data shows that compared to 2019 and 2021, the pandemic lockdown policy resulted in a decrease in the total number of pollution days and a decrease in the average concentration of particulate matter in the Beijing area in 2020. The terrain characteristics of the Beijing-Tianjin-Hebei (BTH) made it prone to northeast and southwest winds. The highest incidence of aerosol pollution in Beijing occurs in February and March during the spring and winter seasons. Analysis of a typical heavy aerosol pollution process in the Beijing area from 28 February to 5 March 2019 shows that dust and fine particulate matter contributed to the primary pollution; surface air temperature inversion and an average wind speed of less than 3 m/s were conducive to the continuous accumulation of pollutants, which was accompanied by the oxidation reaction of NO2 and O3, forming photochemical pollution. The heavy aerosol pollution was transmitted and diffused towards the southeast, gradually eliminating the pollution. Our results provide relevant research support for the prevention and control of aerosol pollution. [ABSTRACT FROM AUTHOR]

Ultrashort pulse laser shows good potential for heat control improvement in metal additive manufacturing. The challenge of applying ultrashort pulse laser as the heat source is to form a fully melted and dense microstructure. In this study, a picosecond pulse laser is introduced for fabricating single layer Ti6Al4V samples. The results, by examining through X-ray computed tomography (X-CT), scanning electron microscopy (SEM), show that highly dense Ti6Al4V samples were fabricated with optimized process parameters. The analysis of the cross section presents a three-zones structure from top to bottom in the sequence of the fully melted zone, the partially melted zone, and the heat-affected zone. A semi-quantitative study is performed to estimate the thermal efficiency of melted pool formation. The mechanical properties of the samples are tested using nano-indentation, showing an elastic modulus of 89.74 ± 0.74 GPa. The evidence of dense melted pool with good mechanical properties indicates that the picosecond laser can be integrated as the heat source with the current metal additive manufacturing to fabricate parts with accuracy control for the smaller size of thermal filed. [ABSTRACT FROM AUTHOR]

In this paper, we use general Riccati equation to construct new solitary wave solutions of the Van der Waals normal form, which is one of the most famous models for natural and industrial granular materials. It is very important to understand the static and dynamic characteristics of this models in many application fields. We solve the general Riccati equation through different function transformation, and many new hyperbolic function solutions are obtained. Then, it is substituted into the Van der Waals normal form as an auxiliary equation. Abundant types of solitary-wave solutions are obtained by choosing different coefficient in the general Riccati equation, and some of them have not been found in other documents. The results show that the analysis method we used is very simple and effective for dealing with nonlinear models. [ABSTRACT FROM AUTHOR]

Conventional plain organic or inorganic shell for microcapsules has their own drawbacks, the organic shell has defects in thermal conductivity and stability; while the compactness and coverage of inorganic shell are not satisfactory. Herein, a novel approach to synthesis of organic–inorganic composite double‐layer shell phase change microcapsule (DLSPCM) is proposed, which is achieved by forming inorganic outer shell on the surface of organic shell via atomic layer deposition (ALD). Taking the pristine microcapsule with paraffin core and melamine formaldehyde (MF) shell as an example, MF‐ZnO composite double‐layer shell (DLS) is formed in this paper. The melting enthalpy of DLSPCM obtained by 100 ALD cycles is 159.7 J g−1, which is only 12.1 J g−1 lower than that of paraffin @ MF microcapsules (control sample), while the thermal conductivity of DLSPCM surges by 77.8%, and the thermal energy storage ability and thermal regulation performance are basically maintained. After 900 thermal cycles, the heat storage capacity of DLSPCM obtained by 100 ALD cycles decreased by only 3%. Besides, the photocatalytic performance and antibacterial activity of ZnO‐reinforced DLSPCM are further confirmed. The successful design of DLSPCM via ALD is prospective for the encapsulation, modification, and reinforcement of phase change microcapsules. [ABSTRACT FROM AUTHOR]

The shape of the blades of the horizontal agitating ball mill will greatly affect the efficiency of the ball mill. In this article, by bending the end of the mixing blade, using discrete element method and EDEM simulation to study the effect of blade bending angle on the efficiency of ball milling. In this article, the degrees of blade bending are 0 degrees, 3 degrees, 5 degrees, and 10 degrees respectively, and the main technical parameters of powder force between particles, particle accumulation, and energy utilization are selected as the main technical parameters for analysis. The research results show that when the blade bending design is 5°, the powder accumulation rate is reduced by 32.48%, the energy consumption of the stirring shaft is reduced by 14.45%, the powder crushing energy utilization rate is increased by 3.47%, and the ball milling crushing effect is the best good. [ABSTRACT FROM AUTHOR]

Oil–water relative permeability is an important parameter that affects fluid flow in porous media. It is usually obtained in a laboratory. Since rock resistivity and relative permeability are both effects of water saturation, they should theoretically have a relationship. Based on the parallel conduction principle of fluid and skeleton in porous media, the pore structure and fluid distribution can be simplified using the Kozeny–Carman permeability correction equation and the Archie formula, and the relative permeability model of the water phase can be deduced under different wetting conditions. In this study, the resistivity and relative permeability experimental data of 20 rock samples from four inspection wells were compared and verified. The results show that the proposed oil–water relative permeability model agrees well with a reservoir having a porosity range of 17.6–30.7% and an air permeability of 0.16–973 × 10−3 μm, and it may explain why the relative permeability of the water phase decreases as water saturation increases. This model could provide a new technique to construct the relative permeability curves of sandstone reservoirs. [ABSTRACT FROM AUTHOR]

Functionalized multiwalled carbon nanotubes (MWCNTs)-reinforced copper (Cu) composites were prepared by the combination of electrowinning and hot-pressing sintering and cold rolling process. The influence of the functionalization of MWCNTs on the strength and electrical properties of MWCNTs/Cu composites was studied. Functional group was introduced to increase the wetting of water electrolytes, improve the poor wettability of MWCNTs and form a highly active surface suitable for the preparation of MWCNTs/Cu composites by electro-deposition, enabling MWCNTs to be evenly dispersed in Cu matrix. Studies have shown that the addition of 1% of functionalized MWCNTs composite can increase the tensile strength by 6% and 165% compared with the addition of unfunctionalized and pure copper. It's worth noting that the increase of oxygen-containing functional group brought about by functionalized MWCNTs did not significantly reduce the electrical properties of composites. The main reason for this is the good dispersion of the treated MWCNTs in Cu matrix and the bridging for electronic transmission, ensuring that the high electrical properties of MWCNTs/Cu composites are just slightly lower than those of electrolytic pure copper (99.92% IACS). [ABSTRACT FROM AUTHOR]

Since the implementation of the comprehensive housing reform in 1998, the real estate market in China has continued to boom, and the proportion of housing expenditure in residents' income has been increasing, which has an increasingly significant impact on residents' consumption. A regression model is constructed based on the relevant data of urban residents from 1992 to 2019 and the impact of changes in housing expenditures and residential expenditures on household consumption is explored. Meanwhile, time series models of the United States and Japan were constructed for comparative study. The results show that the housing purchase expenditure and residential expenditure in China have a certain degree of crowding-out effect on household consumption; the increase in purchase expenditure in the United States and Japan can stimulate consumption to a certain extent, and the rise in residential expenditure has no significant impact on American household consumption but positive promoting the consumption of Japanese residents. Based on the empirical results, a comparative analysis of the reasons why housing expenditure inhibits household consumption in China is made, and the relevant policy suggestions are put forward in the paper. [ABSTRACT FROM AUTHOR]

In order to solve the problem of low charge and discharge efficiency in graphite anode materials for lithium-ion batteries, low-cost artificial graphite can be used and doped WILL micro-nano porous Si-Ag particles to improve the conductivity of graphite and increase the efficiency of charge and discharge. The micro-nano porous Si-Ag powder !s prepared via chemical etching method, and ball mill 70% artificial graphite and 30% porous S-Ag powder to form a sandwiched composted structure. SEM,TEM,XRD and battery testing systems were used to characterize and test porous S-Ag powder material. According to the research results, the silicon parities have a of 720 nm after high-energy ball milling; under the etching conditions of 80, the obtained micro-nano porous S-Ag anode material has a charge discharge specific capacity of 2 163. 28 mAh/g;doped with porous S-The first charge and discharge specific cupidity of the graphite negative electrode after Ag particles can reach 1 227. 966 mAh/g, which !s 341. 1% higher than that of pure graphite anode material that a current density of 0. 2 C(1 C= 1 500 mA/g), The retention rate of the cupidity after 100 cycles is 59. 72%. [ABSTRACT FROM AUTHOR]

In order to solve the problem of agglomeration of graphene in preparation of composites, GN-CeO2 powders with even dispersion were obtained by a hydrothermal reduction method, which involved modifying the surface of acidified graphene by cerium nitrate. Then, Al/GN-CeO2 composite powders and materials were prepared by high-energy ball milling and vacuum hot pressing, respectively. The details were investigated, including the effect of modification process on the surface morphology and functional groups of graphene and modification time on the properties of Al/GN-CeO2 composites. The result shows that the functional groups and defects of graphene were added by the treatment of acidification process, which is beneficial to the composite of graphene and CeO2 particles. The quantity of CeO2 deposition on graphene surface increased with the duration of hydrothermal reduction time. After 6 h modification, the properties of the composites performed best. Compared with Al/GN composites, the tensile strength of the modified composites was increased from 284 MPa to 321 MPa; and the tensile strain rate of the modified composites was increased to 12.3%；the hardness of the modified composites was increased from 97.1 Hv to 99.5 Hv；the conductivity of the modified composites was increased from 29.84%IACS to 33.21%IACS. [ABSTRACT FROM AUTHOR]

When preparing nano silicon powder by high-energy ball milling, the grain size of the obtained nano silicon powder varies with different technical parameters set in the ball milling process. In order to explore the impact of different ball milling technical parameters on the grain size of nano silicon powder, this paper adopted the orthogonal experimental design in combination with fitting analysis, and set the agitator shaft speed of the ball mill and the milling time as the influence factors. Then this paper studied the impact of different ball milling technical parameters on the grain size of nano silicon powder, so as to work out the fitting function model and the optimal technical parameters for preparing nano silicon powder by high-energy ball milling. The experimental results showed that when the ratio of grinding media to material is 20: 1, without considering the influence of other factors such as temperature and humidity, when the agitator shaft speed is 1100/1200 rpm and the milling time is 150 min, the smallest grain size of nano silicon powder could be obtained, and the fitting formula of the agitator shaft speed and grain size is most consistent with the Gaussian approximation, which is 5.157*exp(-((x-706.8)/297.2)^2). This research holds value for practical application. [ABSTRACT FROM AUTHOR]

Recently, some infinite families of binary minimal and optimal linear codes were constructed from simplicial complexes by Hyun et al. Inspired by their work, we present two new constructions of codes over the ring $\mathbb {F}_{2}+u\mathbb {F}_{2}$ by employing simplicial complexes. When the simplicial complexes are all generated by a maximal element, we determine the Lee weight distributions of two classes of the codes over $\mathbb {F}_{2}+u\mathbb {F}_{2}$. Our results show that the codes have few Lee weights. Via the Gray map, we obtain an infinite family of binary codes meeting the Griesmer bound and a class of binary distance optimal codes. [ABSTRACT FROM AUTHOR]

Deep-sea mining (DSM) is an advanced technology. This article is focused on the dynamic analysis of a coupled vessel/riser/equipment system of a DSM based on radial basis function (RBF) neural network approximations while considering vessel dynamic positioning (DP) and active heave compensation (AHC). A coupled model including the production support vessel (PSV), lifting riser, and slurry pump is established containing simulated DP and AHC models. Furthermore, dynamic simulations are implemented to obtain the results of the vessel motions, thruster forces, pump motions and riser tensions. Using optimal Latin hypercube sampling, an RBF neural network approximation model is established, the input includes environmental factors and the output includes the dynamic responses of the pump motion and riser tension. Calculations are performed using RBF network approximations instead of a coupled model. The obtained results show that the PSV wave frequency (WF) motions have significant influence on the dynamic responses of the subsea system. Moreover, the current load affects the compensation effect. The RBF network approximation model can be used to reduce the required calculation time. [ABSTRACT FROM AUTHOR]

Based on the generic construction of linear codes, we construct linear codes over the ring $\mathbb Z_{4}$ via posets of the disjoint union of two chains. We determine the Lee weight distributions of the quaternary codes. Moreover, we obtain some new linear quaternary codes and good binary codes by using the Gray map. [ABSTRACT FROM AUTHOR]

Toddalia asiatica (Linn.) Lam. is a medical plant traditionally used to treat coughs, fevers, and various diseases. Alkaloids are the main active ingredients in Toddalia asiatica (Linn.) Lam., but traditional methods for screening and separation are complex and labor‐intensive. In this work, an efficient strategy was developed to rapidly screen, identify, and separate neuraminidase inhibitors from Toddalia asiatica (Linn.) Lam. Ultrafiltration, high performance liquid chromatography, and time‐of‐flight mass spectrometry were employed for rapid screening and identification of neuraminidase inhibitors. A two‐phase solvent system comprising n‐hexane/ethyl acetate/methanol/water (5:5:3:7, v/v) was then selected for separation by high‐speed counter‐current chromatography. A sample loading of 200 mg and a stepwise flow rate were achieved by increasing the flow rate from 2 to 4 mL/min after 4 h. Three main fluoroquinoline alkaloids (haplopine, skimmianine, and 5‐methoxydictamnine) along with two coumarins were obtained via one‐step separation and their structures were determined by mass spectrometry and nuclear magnetic resonance. In vitro assays revealed skimmianine with half‐maximal inhibitory concentration of 16.2 ± 0.7 µmol/L was selected as the potential highest neuraminidase inhibitor. The results suggest that ultrafiltration high performance liquid chromatography–mass spectrometry combined with high‐speed counter‐current chromatography is efficient for the screening and isolation of neuraminidase inhibitors from complex natural products. [ABSTRACT FROM AUTHOR]

In this letter, we propose a family of almost $M$ -ary $\sigma $ -sequences with good autocorrelation based on cyclotomic classes. The out-of-phase autocorrelation magnitude of these $M$ -ary sequences is upper bounded by 3 or $\sqrt {5}$. [ABSTRACT FROM AUTHOR]

Perovskite solar cells with a single light absorption heterojunction has demonstrated a power conversion efficiency of as high as 23.2% in the past few years. In this work, for the first time, we used quasi-spherical carbon quantum dots (CQDs)-doped PCBM film as the electron transporting layer of an inverted perovskite solar cell. The device structure is FTO/PEDOT:PSS/MAPbI3/PCBM:CQDs/BCP/Ag. The optimized PCE of 18.1% was achieved and a 13% enhancement was observed compared with those of pure PCBM-based devices. Various advanced characterizations including ultrafast spectroscopy, conductive atomic force microscopy, and electronic impedance spectroscopy elucidate that quasi-spherical CQD doping leads to enhanced electrical conductivity, electron mobility, and charge extraction efficiency. Moreover, we find that such CQD doping helps to prevent I− ions from undergoing interface diffusion and thus enhances the stability of solar cells. [ABSTRACT FROM AUTHOR]

Deep-sea mining (DSM) is an advanced concept. A simulation method of coupled vessel/riser/body system in DSM combined with dynamic positioning (DP) is proposed. Based on the three-dimensional potential flow theory, lumped mass method, and Morison’s equations the dynamic models of the production support vessel, riser and slurry pump are established. A proportion integration differentiation (PID) controller with a nonlinear observer and a thrust allocation unit are used to simulate the DP system. Coupled time domain simulation is implemented with the vessel operated in two DP modes. Results of the vessel and pump motions, riser tension, and thruster forces are obtained. It shows that the pump will be lifted by the riser when the vessel is chasing the next set point. Riser tension is influenced by the wave frequency motions of the vessel in positioning mode and low-frequency motions in tracking mode. The proposed simulation scheme is practical to study the DSM operation. [ABSTRACT FROM AUTHOR]

Copper iodide (CuI) thin film grown by a direct vacuum thermal evaporation method at low temperature is utilized as inorganic hole transport layer in planar CH3NH3PbI3−xClx-based perovskite solar cell. The device performance is mainly controlled by the deposition rate of CuI layer for optimized thickness. The reason was investigated in detail by transient photovoltage/photocurrent spectroscopy (TPV/TPC), X-ray photoelectron spectroscopy (XPS), and the energy-dispersive X-ray spectrum (EDS). The results indicate that larger deposition rate leads to a non-stoichiometric CuI layer with excess iodine. More importantly, the redundant iodine is illustrated as the recombination center that results in interface recombination. Under optimized CuI growth condition, a power conversion efficiency of 6.4% has been achieved with a short-circuit current density (JSC) of 16.4 mA/cm2, an open-circuit voltage (VOC) of 730 mV, and a fill factor (FF) of 54%. Our results open a possibility for further improvement of perovskite solar cells by controlling the concentration and distribution of iodine in the perovskite films. [ABSTRACT FROM AUTHOR]