Synthesis of yolk-shell Bi2O3@TiO2 submicrospheres with enhanced potassium storage

Science China Chemistry - Due to their enormous potential for large-scale energy storage, rechargeable potassium-ion batteries have been widely researched and developed. However, the drastic volume...     

软机器人的运动行为研究进展

软机器人的出现不仅弥补了传统机器人的缺点,并逐渐成为机器人领域的热点和前沿之一,近年来该领域研究进展十分迅速。本文总结了典型软机器人的运动行为的研究进展,介绍了软机器人按材质类型的分类(包括液晶软机器人、生物分子软机器人、PDMS软机器人、液体软机器人和自振荡凝胶软机器人)及其功能和潜在应用,讨论了当前不同类别软机器人运动的特点和存在的问题,在此基础上展望了软机器人领域面临的机遇、挑战和未来发展方向。     

Palladium Encapsulated by an Oxygen-Saturated TiO2 Overlayer for Low-Temperature SO2-Tolerant Catalysis during CO Oxidation

The development of oxidation catalysts that are resistant to sulfur poisoning is crucial for extending the lifespan of catalysts in real-working conditions. Herein, we describe the design and synthesis of oxide-metal interaction (OMI) catalyst under oxidative atmospheres. By using organic coated TiO₂, an oxide/metal inverse catalyst with non-classical oxygen-saturated TiO₂ overlayers were obtained at relatively low temperature. These catalysts were found to incorporate ultra-small Pd metal and support particles with exceptional reactivity and stability for CO oxidation (under 21 vol % O₂ and 10 vol % H₂O). In particular, the core (Pd)-shell (TiO₂) structured OMI catalyst exhibited excellent resistance to SO₂ poisoning, yielding robust CO oxidation performance at 120 °C for 240 h (at 100 ppm SO₂ and 10 vol % H₂O). The stability of this new OMI catalyst was explained through density functional theory (DFT) calculations that interfacial oxygen atoms at Pd−O−Ti sites (of oxygen-saturated overlayers) serve as non-metal active sites for low-temperature CO oxidation, and change the SO₂ adsorption from metal(d)-to-SO₂(π*) back-bonding to much weaker σ(Ti−S) bonding.     

Redshift modification of pulsars and magnetars by relativistic plasmas and vacuum polarization

The redshifts of emissions from pulsars and magnetars consist of two components: gravitational and non-gravitational redshifts. The latter results from the electromagnetic and kinetic effects of relativistic plasmas, characterized by refractive indices and streaming velocities of the media, respectively. The vacuum polarization effect induced by strong magnetic fields can modify the refractive indices of the media, and thus leads to a modification to the redshifts. The Gordon effective metric is introduced to study the redshifts of emissions. The modification of the gravitational redshift, caused by the effects of relativistic plasmas and vacuum polarization, is obtained.     

Photon dynamics in plasma waves

In this Letter the evolution of a single photon and collective effect of a photon system in background plasma waves are uniformly described in the framework of photon dynamics. In a small-amplitude plasma wave the modulation of photon dynamical behavior by the plasma wave can be treated as perturbation, and photon acceleration effect and photon Landau damping are investigated in linear theory. In an arbitrary-amplitude plasma wave, photon evolution trajectories in phase space are obtained by solving dynamical equations, and photon trapping effect and motion equations in the given plasma wave are also discussed.     

固相萃取-高效液相色谱测定饲料中新橙皮苷二氢查耳酮和柚皮苷二氢查耳酮

建立了固相萃取-高效液相色谱检测饲料中新橙皮苷二氢查耳酮（NHDC）和柚皮苷二氢查耳酮（Naringin DC）的方法。采用纯甲醇溶液进行超声辅助萃取样品，经HLB固相萃取柱净化后在XB-C₁₈（150 mm×4.6 mm，5 μm）色谱柱上分离，用甲醇/水作为流动相进行梯度洗脱，光电二极管阵列检测器进行检测。结果表明，新橙皮苷二氢查耳酮和柚皮苷二氢查耳酮在0.2~49.0 mg/L范围内具有良好的线性关系，相关系数均>0.999，定量限分别为0.02和0.01 mg/kg。日内和日间精密度分别为0.7%~4.1%和0.9%~6.0%。方法的加标回收率为86.2%~105.0%，相对标准偏差（RSDs）为1.0%~6.3%（n=3）。该方法能有效降低饲料基体成分的干扰，灵敏度高，重现性好，适用于饲料中新橙皮苷二氢查耳酮和柚皮苷二氢查耳酮的定量检测。     

The propagation of a polarized gaussian beam in a smoothly inhomogeneous isotropic medium

In the frame of the eikonal-based complex geometrical optics, which describes the phase front and cross section of a light beam using the quadratic expansion of a complex-valued eikonal, we investigate the transverse deflections of a polarized Gaussian beam (GB) in a smoothly inhomogeneous isotropic medium, which is called the spin Hall effect of the beam. The linear complex-valued eikonal terms are introduced firstly to describe the polarization-dependent transverse shifts of the beam in the inhomogeneous medium. We find that the polarization-dependent transverse shifts of the beams include two parts: one originates from the coupling between the spin angular momentum and the extrinsic orbital angular momentum due to the curve trajectory of the center of gravity of the polarized GB, and the other from the coupling between the spin angular momentum and the intrinsic orbital angular momentum due to the rotation of the beam with respect to the central ray.     

Generation of Circular Optical Vortex Array

We report on a novel optical vortex array named circular optical vortex array, which is generated by the superposition of two concentric perfect optical vortices. The circular optical vortex array has a constant topological charge of +1 or ?1, the number and sign of which are determined by the topological charges of the two perfect optical vortices. Moreover, the radius of the circular optical vortex array is easily adjusted by using the cone angle of an axicon. Furthermore, the circular optical vortex array and multiple circular optical vortex array can be rotated by changing the initial phase difference of the perfect optical vortices on demand. This work demonstrates a complex structured optical field, which is of significance for applications such as optical tweezers, micro‐particle manipulation, and optical imaging.     

Ice Melting to Release Reactants in Solution Syntheses

Aqueous solution syntheses are mostly based on mixing two solutions with different reactants. It is shown that freezing one solution and melting it in another solution provides a new interesting strategy to mix chemicals and to significantly change the reaction kinetics and thermodynamics. For example, a precursor solution containing a certain concentration of AgNO₃ was frozen and dropped into a reductive NaBH₄ solution at about 0 °C. The ultra‐slow release of reactants was successfully achieved. An ice‐melting process can be used to synthesize atomically dispersed metals, including cobalt, nickel, copper, rhodium, ruthenium, palladium, silver, osmium, iridium, platinum, and gold, which can be easily extended to other solution syntheses (such as precipitation, hydrolysis, and displacement reactions) and provide a generalized method to redesign the interphase reaction kinetics and ion diffusion in wet chemistry.