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Designing cost-effective and high-performing metal catalysts is significant for many renewable energy conversion technologies. Lowering metal loading without sacrificing activity and durability is highly desired for the catalyst design, especially for those reactions where the noble metals deliver the best catalyzing performance. Single-atom catalysts (SACs) with maximal metal-atom utilization, homogeneous and tailorable active sites have emerged as promising catalyst candidates, where the local coordination structures of the metal atoms in SACs largely determine the reaction kinetics. Previous design strategies of constructing strong metal-support interactions can stabilize the individual metal atoms in SACs, but present obstacles to provide a flexible manipulation platform for elaborately tailoring the coordination structures to achieve performance optimization towards a specifically targeted reaction. Here, for the proof-of-concept study, we report a novel design of SAC with iridium (Ir) single atoms supported on conjugated polymer, in which the adsorption energies of reaction intermediates on Ir atoms and the reaction kinetics towards acidic water oxidation can be readily optimized through modulating the formed cation-π interactions that can be tailored by adjusting the molecular structures of conjugated polymers. This strategy establishes a general route to develop targeted SACs for various catalytic reactions. [ABSTRACT FROM AUTHOR]

In this paper, a feasible expectation-conditional-maximization (ECM) algorithm is developed for finding the maximum likelihood estimates of parameters of the skew-normal based stochastic frontier model. The closed-form formulas for updating parameters in CM-steps are derived. The proposed methodology is illustrated with simulations and a real data example, where we find the new ECM algorithm outperforms the numerical approach adopted in the previous study. [ABSTRACT FROM AUTHOR]

The advanced microstructure of the elongated grain structure with intensive texture, which mainly consists of 112 110 α and 332 113 α components, significantly improves the toughness of 1.5 GPa ultra-high strength steel by delamination toughening. The elongated grain structure with texture affects the microstructure evolution of heat affected zone (HAZ), resulting in the refinement of coarse-grained HAZ(CGHAZ), the separate distribution of granular bainite and lath martensite in fine-grained HAZ (FGHAZ) and the formation of clustered blocky martensite in intercritical HAZ (ICHAZ). In ICHAZ, the sharp 112 100 α of untransformed grains does not undergo reorientation for high thermal stability. For transformed grains, initial 112 110 α and 332 113 α components are reproduced by texture heredity. However, with the increase of peak temperature, the heredity tendency of texture weakens, causing the reduction of texture intensity. In CGHAZ, the Goss and 112 110 α texture are obtained because of grains oriented growth. It is found that serious and heterogenous HAZ softening is a significant feature. FGHAZ becomes the weakest zone due to the massive formation of granular bainite. Due to the disappearance of 332 113 α and the formation of Goss texture, CGHAZ shows the least modulus. [ABSTRACT FROM AUTHOR]

During the batch assembly analysis of linear axis of machine tool, assembly quality evaluation is crucial to reduce assembly quality fluctuations and improve efficiency. This study presented a data-driven modeling approach for evaluating assembly quality of linear axis based on normalized mutual information and random sampling with replacement (NMI-RSWR) variable selection method, synthetic minority over-sampling technique (SMOTE), and genetic algorithm (GA)-optimized multi-class support vector machine (SVM). First, a variable selection method named NMI-RSWR was proposed to select key assembly parameters which affected assembly quality of linear axis. Then, a hybrid method based on SMOTE and GA-optimized multi-class SVM was presented to construct assembly quality evaluation model. In this method, Class imbalance problem was solved by using SMOTE, and parameters optimization problem was solved by using GA. Finally, the assembly-related data from the batch assembly of x-axis of a three-axis vertical machining center were collected to validate the proposed method. The results indicate that the proposed NMI-RSWR approach has capacity for selecting the highly related assembly parameters with assembly quality of linear axis, and the proposed data-driven modeling approach is effective for assembly quality evaluation of linear axis. [ABSTRACT FROM AUTHOR]

Lipid-polymer hybrid nanoparticles (LPNs) are promising drug delivery systems in various of disease treatment areas, particularly for cancer treatments. Here, a water-insoluble antitumor agent, hydroxycamptothecin (HCPT), was successfully incorporated into LPNs formed from polylactic-co-glycolic acid (PLGA), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-(methoxy(polyethylene glycol)-2000) (DSPE-PEG2000), and lecithin, by a modified single emulsification-solvent evaporation method. Quality-by-design (QbD) strategy composed of Plackett–Burman and Box–Behnken designs were applied for optimizing HCPT-LPNs with desired properties. The optimized HCPT-loaded lipid-polymer hybrid nanoparticles (HCPT-LPNs) were on the nanoscale, with a final size of 220.9 nm, drug loading of 2.50%. HCPT-LPNs were highly stable in plasma and had pH- and drug loading-related sustained release characteristics. The in vitro cytotoxicity of HCPT-LPNs against MCF-7 and HepG2 cells showed that HCPT-LPNs had higher in vitro cytotoxicity than HCPT solution (HCPT-Sol) with reduced cell viability and IC50 values. In vivo pharmacokinetic assays demonstrated that the AUC of HCPT-LPNs was more than 3 times higher than that of HCPT-Sol after tail vein injection in SD rats. Tumor growth was significantly inhibited compared with HCPT-Sol after a single tail vein injection of HCPT-LPNs in murine LLC-GFP-luc lung cancer bearing mice at a dose of 6 mg/kg, without severe side effects. These results indicate that HCPT-LPNs are the promising drug delivery system for antitumor treatments. [ABSTRACT FROM AUTHOR]

Photoelectrochemical deposition technology has been applied to the process of electrolytic manganese dioxide production. The effect of light on the electrochemical behavior of the electrodeposited manganese dioxide was studied by the cyclic scanning method, electrochemical impedance method, and chronoamperometry method. Illumination increased the peak current of electrolytic manganese dioxide anodization, reduced the charge transfer resistance, and provided a greater driving force for nucleation and growth of manganese dioxide. In addition, photoelectrochemical constant-current deposition of manganese dioxide was used. Photoelectrochemical deposition reduced the ~ 50 mV cell voltage, improved the current efficiency by approximately 11%, and reduced the power consumption by approximately 13%. Photoelectrochemical deposition is beneficial to energy saving and consumption reduction in the production process of electrolytic manganese dioxide. [ABSTRACT FROM AUTHOR]

In this work, a novel calix[4]resorcinarene-based ionic liquid (C4RA-2IL) was synthesized, structurally characterized, and statically coated on capillary column as stationary phase for capillary gas chromatography (GC). The column efficiency of the C4RA-2IL column is 3345 plates m−1, which are determined by n-dodecane at 120 °C. Based on its McReynolds constants, the C4RA-2IL column showed moderate polarity. Particularly, the C4RA-2IL column show high separation performance for a wide range of analytes and some difficult separation of meta/para-isomers. Moreover, it exhibited excellent selectivity for critical aromatic isomers of chloroaniline, bromaniline, iodoaniline, toluidine and xylidine isomers and shows advantageous separation capability over the commercial polysiloxane stationary phase. This work presents a promising future of calixarene-based ionic liquid as a new type of stationary phase in GC separations. [ABSTRACT FROM AUTHOR]

We have investigated the interaction properties of multi-Airy-Gaussian beams under the in-phase and out-phase conditions, respectively. For the case of three Airy–Gaussian beams, the breathing solitons with single, two and three components can be observed under certain conditions. The breathing solitons with single, three and four components can be observed for four Airy–Gaussian beams. The types of breathing solitons for out-phase multi-Airy–Gaussian beams are less than that of in-phase multi-Airy–Gaussian beams. Furthermore, the types of breathing solitons can be controlled by adjusting the space interval, nonlinear parameter and self-accelerating direction. [ABSTRACT FROM AUTHOR]

Glioblastomas are highly malignant brain tumors. Knowledge of growth rates and growth patterns is useful for understanding tumor biology and planning treatment logistics. Based on untreated human glioblastoma data collected in Trondheim, Norway, we first fit the average growth to a Gompertz curve, then find a best fitted white noise term for the growth rate variance. Combining these two fits, we obtain a new type of Gompertz diffusion dynamics, which is a stochastic differential equation (SDE). Newly collected untreated human glioblastoma data in Seattle, US, re-verify our model. Instead of growth curves predicted by deterministic models, our SDE model predicts a band with a center curve as the tumor size average and its width as the tumor size variance over time. Given the glioblastoma size in a patient, our model can predict the patient survival time with a prescribed probability. The survival time is approximately a normal random variable with simple formulas for its mean and variance in terms of tumor sizes. Our model can be applied to studies of tumor treatments. As a demonstration, we numerically investigate different protocols of surgical resection using our model and provide possible theoretical strategies. [ABSTRACT FROM AUTHOR]

ZnO/HfO2:Eu nanocables were prepared by radio frequency sputtering with electrospun ZnO nanofibers as cores. The well-crystallized ZnO/HfO2:Eu nanocables showed a uniform intact core–shell structure, which consisted of a hexagonal ZnO core and a monoclinic HfO2 shell. The photoluminescence properties of the samples were characterized. A white-light band emission consisted of blue, green, and red emissions was observed in the nanocables. The blue and green emissions can be attributed to the zinc vacancy and oxygen vacancy defects in ZnO/HfO2:Eu nanocables, and the yellow–red emissions are derived from the inner 4f-shell transitions of corresponding Eu3+ ions in HfO2:Eu shells. Enhanced white-light emission was observed in the nanocables. The enhancement of the emission is ascribed to the structural changes after coaxial synthesis. [ABSTRACT FROM AUTHOR]

We investigate the propagation property of circular Airy beams in photorefractive nonlinear media by differential method. The abruptly autofocusing behavior of circular Airy beams in free space is first discussed. The intensity contrast will increase with the decreasing of decay factor and the focal length will also increase with the increasing of initial radius. When photorefractive nonlinearity is introduced, the energy diffusion of circular Airy beams after autofocusing behavior can be manipulated. The periodic breather soliton can be obtained when the energy diffusion is suppressed by appropriately photorefractive nonlinearity. If the photorefractive nonlinearity is large enough, the abruptly autofocusing behavior is suppressed completely and the circular Airy beam can form the bracelet breather soliton. [ABSTRACT FROM AUTHOR]

We investigate numerically the propagation and interaction characteristics of finite-energy Airy-Hermite-Gaussian beams in biased photorefractive media. For the case of first-order Hermite polynomial, two main lobes of the initial input beam can form breathing solitons with two components. The interval between two soliton components in the y-direction increases gradually with the propagation distance, while the central position of two soliton components in the x-direction is almost unchanged during propagation. Moreover, in interaction situations, four main lobes of the two Airy-Hermite-Gaussian beams can also form breathing solitons with four components under the in-phase and out-of-phase conditions, respectively. [ABSTRACT FROM AUTHOR]