Enhanced electrochemical performance of Si/C electrode through surface modification using SrF_(2) particle

The silicon-based material exhibits a high theoretical specific capacity and is one of the best anode for the next generation of advanced lithium-ion batteries(LIBs).However,it is difficult for the silicon-based anode to form a stable solid-state interphase(SEI)during Li alloy/de-alloy process due to the large volume change(up to 300%)between silicon and Li4.4Si,which seriously limits the cycle life of the LIBs.Herein,we use strontium fluoride(SrF_(2))particle to coat the silicon-carbon(Si/C)electrode(SrF_(2)@Si/C)to help forming a stable and high mechanical strength SEI by spontaneously embedding the SrF_(2) particle into SEI.Meanwhile the formed SEI can inhibit the volume expansion of the silicon-carbon anode during the cycle.The electrochemical test results show that the cycle performance and the ionic conductivity of the SrF_(2)@Si/C anode has been significantly improved.The X-ray photoelectron spectroscopy(XPS)analysis reveals that there are fewer electrolyte decomposition products formed on the surface of the SrF_(2)@Si/C anode.This study provides a facile approach to overcome the problems of Si/C electrode during the electrochemical cycling,which will be beneficial to the industrial application of silicon-based anode materials.

Corrosion mechanism of magnesia-chromite refractories by ZnO-containing fayalite slags: Effect of funnel glass addition

An efficient approach for lead extraction from waste funnel glass through the lead smelting process has been proposed. To clarify the effect of funnel glass addition on the degradation of magnesia-chromite refractories by ZnO-containing fayalite slag, the corrosion behavior of magnesia-chromite refractories in lead smelting slags with different funnel glass additions from 0wt% to 40wt% was tested. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) was used to acquire the microstructural information of the worn refractory samples. Experimental results showed that the corrosion of magnesia-chromite refractory consisted predominantly of the dissolution of MgO into slag. ZnO and FeO reacted with periclase and chromite to form (Zn,Fe,Mg)O solid solution and (Zn,Fe,Mg)(Fe,Al,Cr)2O4 spinel, respectively. With the addition of funnel glass, the solubility of MgO increased whereas ZnO levels remained stable, thereby resulting in a reduced Mg content and an elevated Zn and Fe content in the (Zn,Fe,Mg)O solid solution and the (Zn,Fe,Mg)(Fe,Al,Cr)2O4 spinel. Considering the stability of the (Zn,Fe,Mg)O solid solution layer and the penetration depth of the slag, the optimal funnel glass addition for lead smelting was found to be 20wt%.

Tightly focused properties of a partially coherent radially polarized power-exponent-phase vortex beam

A partially coherent beam called a radially polarized multi-Gaussian Schell-model power-exponent-phase vortex beam is introduced. Both the analytical formula of the beam propagating through the high-numerical-aperture objective lens based on the vectorial diffraction theory, and the cross-spectral density matrix of the beam in the focal region are derived. Then,the tight focusing characteristics of the partially coherent radially polarized power-exponent-phase vortex beam are studied numerically, and the intensity distribution, degree of polarization and coherence of the beams in the focusing region with different topological charge, power order, beam index and coherence width are analyzed in detail. The results show that the contour of the spot becomes clearer and smoother with the increase in the beam index, and the focal fields of different structures that include the flattened beam can be obtained by changing the coherence width. In addition, by changing the topological charge and power order, the intensity can gather to a point along the ring. These unique properties will have potential applications in particle capture and manipulation, especially in the manipulation of irregular particles.

Boost VS_(2) electrochemical reactive kinetics by regulating crystallographic planes and coupling carbon matrix for high performance sodium-ion storage

Vanadium disulfide(VS_(2)) as a typical two-dimensional transition metal chalcogenide has excellent competitiveness for sodium-ion storage due to its wide layer spacing(0.575 nm),high theoretical capacity of 932mAh·g^(-1) originating from multi-electron electrochemical redox.However,continuous sodiation process accompanied by crystal structural evolution and collapse cause rapid capacity decaying.Herein,novel few-layer VS_(2)nanosheets with open(001) crystal planes are in-situ constructed on reduced graphene oxide to solve these issues mentioned above.It indicates that few-layer VS_(2)provides more Na^(+) storage activity due to the low Na^(+)surface migration energy barrier on exposed crystal(001)planes.The flexible and high electronic conductivity of carbon matrix also effectively builds multi-level buffer structure and electron transport kinetics to boost the Na^(+)insertion/conversion reactive activity on VS_(2) as well as Na^(+) pseudocapacitance storage kinetics on edges and defects of nano sheets.Those coupling effects result in high rate capability and long cycling stability as a battery/capacitor anode.It delivers conspicuous high energy density of 81 and 40 Wh·kg^(-1) at power density of 118 and 10,286W·kg^(-1),as well as 80% energy retention rate after 5000cycles,confirming its great application potential in sodiumbased storage devices.

Recovery of vanadium and molybdenum from spent petrochemical catalyst by microwave-assisted leaching

The study of the leaching of vanadium(V) and molybdenum(Mo) from spent petrochemical catalysts in sodium hydroxide(NaO H) medium was performed using two approaches, namely, conventional leaching and microwave-assisted leaching methods. The influence of microwave power, leaching time, leaching temperature, and NaOH concentration on the leaching efficiency of spent petrochemical catalyst was investigated. Under microwave-assisted conditions(600 W, 10 min, 90°C, 2.0 mol·L^(-1) NaOH, and 0.20 g·mL^(-1) solid–liquid ratio), the leaching efficiencies of V and Mo reached 94.35% and 96.23%, respectively. It has been confirmed that microwave energy has considerable potential to enhance the efficiency of the leaching process and reduce the leaching time. It is suggested that the enhancement of the leaching efficiencies of V and Mo can be attributed to the existence of a thermal gradient between solid and liquid and the generation of cracks on the mineral surface.

Ultra fast microwave-assisted leaching for the recovery of copper and tellurium from copper anode slime

The decomposition of copper anode slime heated by microwave energy in a sulfuric acid medium was investigated. Leaching experiments were carried out in a multi-mode cavity with microwave assistance. The leaching process parameters were optimized using response surface methodology（RSM）. Under the optimized conditions, the leaching efficiencies of copper and tellurium were 99.56% ± 0.16% and 98.68% ± 0.12%, respectively. Meanwhile, a conventional leaching experiment was performed in order to evaluate the influence of microwave radiation. The mechanism of microwave-assisted leaching of copper anode slime was also investigated. In the results, the microwave technology is demonstrated to have a great potential to improve the leaching efficiency and reduce the leaching time. The enhanced recoveries of copper and tellurium are believed to result from the presence of a temperature gradient due to the shallow microwave penetration depth and the superheating at the solid-liquid interface.

Recent Advances in Bio-Inspired Versatile Polydopamine Platforms for “Smart” Cancer Photothermal Therapy

Although photothermal therapy(PTT)has been developed for fighting cancers,the degradative,toxic,and metabolic nature of photothermal conversion materials(PCMs)has prevented them from being clinically implemented.Taking advantage of the surface modification strategy of mussel-inspired dopamine chemistry and its excellent photothermal conversion effect,polydopamine(Pdop)represents a versatile PTT platform,providing strategies and methods for the construction of novel Pdop-functionalized PCMs.Thanks to its adhesion and secondary reactivity,Pdop can be deposited on virtually all substrates to improve their bioavailability and biocompatibility.Pdop-based PCMs could not be only functionalized with small biomolecules via chemical bonds and/or noncovalent force but also modified with functional polymers via either the“grafting to”or“grafting from”method.This review highlights the synthetic methods,therapeutic strategies,and designs of PCMs based on Pdop in recent years to explore its scope and limitations.

Diagnosis of Kaposi sarcoma by a modified fine needle aspiration method combing cell block in Chinese patients with human immunodeficiency virus/acquired immunodeficiency syndrome

To the Editor:Kaposi’s sarcoma(KS),a low-grade vascular tumor,is one of the most common neoplasms reported in patients with acquired immunodeficiency syndrome(AIDS).Based on epidemiological and clinical characteristics,four types of KS have been reported:classic KS,endemic KS(in equatorial Africa),AIDS-associated KS(AIDS-KS),and iatrogenic KS.Clinically,the presentation of KS can be variable with dark or brown macules,plaques,or nodules that may bleed or,ulcerate on the skin and mucous membranes.Besides,the lymph nodes and some visceral organs can also be involved in more advanced stages of the disease.

卟啉衍生物及其高分子材料

卟啉是一类由4个吡咯环通过次甲基相连而形成的共轭大环化合物.卟啉及其衍生物广泛存在于生物体内,参与催化、氧的输运和能量转移等重要生理过程.因其独特的生理功能和物理化学特性,卟啉衍生物及其高分子材料的制备和合成引起了广泛关注.本文介绍了卟啉及其衍生物在生命系统中的功能及其合成方法,回顾了含卟啉的高分子材料和超分子组装体的设计和制备方法,总结了近年来基于卟啉的高分子和超分子功能材料的研究动态.

In-situ synchrotron high energy X-ray diffraction study of spontaneous reorientation of R phase upon cooling in nanocrystalline Ti_(50)Ni_(45.5)Fe_(4.5)alloy

This study investigated a peculiar phenomenon of self-reorientation of thermally formed R phase in nanocrystalline Ti_(50)Ni_(45.5)Fe_(4.5)by means of in-situ syn-chrotron high energy X-ray diffraction(HE-XRD).Two samples with different average grain sizes of 40 and 90 nm were investigated.R phase in the 40-nm grain size sample was found to self-reorient gradually upon cooling,whereas the same phenomenon did not occur in the 90-nm grain size sample.This self-reorientation process is attributed to the development and evolution of an internal stress anisotropy caused by the second order continuous lattice distortion of R phase upon further cooling in the small nanograined matrix,which lacks the self-accommodation mechanism for internal stress cancellation.

Impact of the cold surge event in January 2021 on the power system of China

During 6-10 January 2021,a recorded strong cold surge took place in China,with over 800 observational stations reaching their historical extremes.Unlike previous studies that focused on the response of either the power load or generation separately,this study quantitatively revealed the impacts on the balance between the demand and supply sides of the grid.On the demand side,the sensitivity of power load was found to increase substantially higher in southern China(0.533 GW°C^(−1))than in the northern region(0.139 GW°C^(−1))due to the limited municipal heating system.On the supply side,the hourly wind power generation dropped from the highest of 110 GW on 6 January to the lowest of 54 GW on 9 January due to the reduction in wind speed.In addition,a reduction in solar power generation was observed during 8-10 January.Thus,the balance of the power system was influenced by this cold event.As an effective adaptation measure,results further showed that early warning by three weeks ahead can be obtained by an operational climate model.The sensitivity of China's power system to such cold surge events may increase remarkably due to the expected increase in the proportion of wind and solar power generation in future new-type power systems.Thus,close cooperation between climate scientists and power engineers is needed to build the resilience of the power system to the cold extremes.

Nanosheet-coated synthetic wood with enhanced flame-retardancy by vacuum-assisted sonocoating technique

Compared to natural woods,synthetic woods have superior mechanical stability,thermal insulation,and flame retardancy owing to their hierarchically cellular microstructures and intrinsic advantages of the thermosetting matrix.Increasing the long-time fire resistance is very important to the practical application.In this study,we present a novel coating strategy by a vacuum-assisted sonication technique(sonocoating)with a rectorite nanosheet dispersion to create a uniform nanocoating on the channel walls of synthetic wood.Owing to ultrasonic energy and vacuum pressure,the nanosheet dispersion can penetrate deep down to form a layered nanocoating on the channel surface.The coated synthetic woods can withstand fire(400-600℃)for more than 10 min with 62%mass retainment,surpassing uncoated synthetic woods and natural woods.Therefore,as a lightweight and strong composite with enhanced flame-retardant performance,the coated synthetic woods have huge potential applications in safe and energy-efficient buildings.