Rationalizing the impact of oxygen vacancy on polysulfide conversion kinetics for highly efficient lithium-sulfur batteries

The“shuttle effect”of lithium polysulfides(LiPSs)is a huge challenge for practical use of high-energydensity lithium-sulfur(Li-S)batteries,and one of the main reasons is the sluggish kinetics of sulfur conversion.Metal oxides are able to expedite the sulfur electrochemistry,and the structural defects enhance the adsorption-conversion ability of metal oxides for polysulfides.However,a significant research gap still remains regarding the relationship between the oxygen vacancy concentration and the adsorptivecatalytic performance of metal oxides.Herein,we establish a correlation between oxygen vacancy concentration and adsorptive-catalytic properties by using tungsten oxide(WO_(x))as model catalysts.It is revealed that high-concentration oxygen vacancy is beneficial for enhancing the binding between tungsten oxide and LiPSs,reducing the energy barrier of Li_(2)S decomposition,and promoting polysulfide conversion kinetics.Consequently,the Li-S batteries using the tungsten oxide with high-concentration oxygen vacancies deliver high initial discharge capacity of 1169 mA h g^(-1)at 0.2 C and 865 mA h g^(-1)at 2 C,low attenuation rate of 0.064%per cycle over 1100 cycles at 2 C.With a high sulfur area loading of 5.34 mg cm^(-2),the Li-S batteries still exhibit high initial gravimetric capacity of 982 mA h g^(-1)at 0.1 C and areal capacity of 5.92 mA h cm^(-2).This work promotes the feasibility of defect engineering on metal oxides as an effective mean to enhance the practicality of Li-S batteries.

Accumulative Effect of Soil Organic Carbon and Nitrogen in Water-Stable Aggregates and Soil Stability Characteristics of Robinia pseudoacacia Plantation in the Loess Hilly-Gully Region

Soil water-stable aggregates (WSAs) are the basic unit of soil constitution and can contribute to remaining the stable soil constitution. The objective of this study was to clarify the distribution and stability of WSAs and the soil organic carbon (SOC), the total nitrogen (TN), and the total phosphorus (TP) concentrations in 0 - 20 cm and 20 - 40 cm soil layers under the different ages of Robinia pseudoacacia plantations. The 20, 25, 40, and 50 years-old Robinia pseudoacacia plantations were selected. Stepwise regression analysis showed that >5 mm and 1 - 2 mm WSAs, SOC concentration in 2 - 5 mm WSAs, and TN and TP concentrations in < 0.25 mm WSAs were dominant independent variables affecting aggregate stability and that SOC in 0.25 - 0.5 mm WSAs, TN in <0.25 mm and 1 - 2 mm WSAs and TP in 2 - 5 mm WSAs were dominant independent variables affecting SOC, TN, and TP concentrations in bulk soils.

Neuroimaging features in a patient with non-ketotic hyperglycaemic seizures: A case report

BACKGROUND Non-ketotic hyperglycaemic(NKH)seizures are a rare neurological complication of diabetes caused by hyperglycaemia in non-ketotic and non-hyperosmotic states.The clinical characteristics of NKH seizures are atypical and lack unified diagnostic criteria,leading to potential misdiagnoses in the early stages of the disease.CASE SUMMARY This report presents a rare case of NKH seizures in a 52-year-old male patient with a history of type 2 diabetes mellitus.We performed comprehensive magnetic resonance imaging(MRI)studies at admission,12 d post-admission,and 20 d post-discharge.The imaging techniques included contrast-enhanced head MRI,T2-weighted imaging(T2WI),fluid-attenuated inversion recovery(FLAIR),diffusion-weighted imaging,susceptibility-weighted imaging,magnetic reso-nance spectroscopy(MRS),and magnetic resonance venography.At the time of admission,T2WI and FLAIR of the cranial MRI showed that the left parieto-occipital cortex had gyrus-like swelling and high signal,and subcortical stripes had low signal.MRS showed a reduced N-acetylaspartate peak and increased creatine and choline peaks in the affected areas.A follow-up MRI 20 d later showed that the swelling and high signal of the left parieto-occipital cortex had disappeared,and the low signal of the subcortex had disappeared.CONCLUSION This case study provides valuable insights into the potential pathogenesis,diagnosis,and treatment of NKH seizures.The comprehensive MRI findings highlight the potential utility of various MRI sequences in diagnosing and characterizing NKH seizures.

色彩捕捉者——淀粉与碘的美妙邂逅

淀粉是一种植物多糖,通常由直链淀粉和支链淀粉两部分组成。淀粉遇碘显蓝色的性质,早已被人们所知晓,并因其显色非常灵敏而在检验碘或淀粉存在的实验中被广泛应用。然而,淀粉遇碘显色不一定是蓝色,其显色与淀粉组成有直接关系。本文通过探究不同食物淀粉及不同因素(淀粉浓度、碘伏浓度、温度、酸碱度、聚合度)遇碘显色不同,科普色彩捕捉之淀粉与碘的美妙邂逅,感受淀粉邂逅碘的神奇显色之趣。本科普实验材料均取自常见食物淀粉以及消毒水碘伏等,成本低,绿色环保无毒安全易操作。通过淀粉与碘不同显色制备绿色环保多色墨水,融合传统书法、国画等创作书法和国画作品;尝试神奇的碘钟反应、碘熏法指纹勘测、淀粉制备非牛顿流体等体验化学实验的奇妙与乐趣,受众面广,实现梯度科普,趣味性强,通过线下体验活动,感受化学之趣、色彩之美,启发对化学的兴趣与热爱,收获良好的科普效果。

Evaluating the Impact of Transcutaneous Electrical Nerve Stimulation on Patients Undergoing Inguinal Hernia Surgery: A Meta- Analysis of Randomized Controlled Trials

Objective:A comprehensive meta-analysis based on the latest randomized controlled trials(RCTs)was conducted to investigate the effects of transcutaneous electrical nerve stimulation(TENS)on patients undergoing treatment after inguinal hernia surgery.Methods:A detailed search of Embase,PubMed,Web of Science,and the Cochrane Library was performed for RCTs investigating the use of TENS during inguinal hernia surgery up to September 28,2021.The Cochrane tool was applied to assess the risk of bias in the included studies.Results:Seven eligible RCTs with a total of 379 cases were included.The meta-analysis showed a mean difference(MD)in VAS of-1.61[95%CI:-2.20-1.02,P<0.00001]at 2 hours post-operation,VAS MD=-1.33 at 4 hours post-operation[95%CI:-2.84-0.18,P=0.09],VAS MD=-2.36 at 8 hours post-operation[95%CI:-4.04-0.69,P=0.006],and VAS MD=-1.75 at 24 hours post-operation[95%CI:-2.64-0.85,P=0.0001].The cortisol level MD at 24 hours post-operation was-52.56[95%CI:-168.8-63.76,P=0.38].Conclusion:TENS significantly reduces postoperative pain following inguinal hernia surgery and promotes patient recovery.TENS is recommended for patients undergoing inguinal hernia surgery.However,further high-quality studies are needed to confirm additional effects.

Electrodeposition of a dendrite-free 3D Al anode for improving cycling of an aluminum-graphite battery

Aluminum-metal batteries show great potential as next-generation energy storage due to their abundant resources and intrinsic safety.However,the crucial limitations of metallic Al anodes,such as dendrite and corrosion problems in conventional aluminum-metal batteries,remain challenging and elusive.Here,we report a novel electrodeposition strategy to prepare an optimized 3D Al anode on carbon cloth with an uniform deposition morphology,low local current density,and mitigatory volume change.The symmetrical cells with the 3D Al anode show superior stable cycling(>450 h)and low-voltage hysteresis(~170 mV)at 0.5 mA cm^(−2).High reversibility(~99.7%)is achieved for the Al plating/stripping.The graphite||Al‐4/CC full batteries show a long lifespan of 800 cycles with 54 mAh g^(−1) capacity at a high current density of 1000 mA g^(−1),benefiting from the high capacitive-controlled distribution.This study proposes a novel strategy to design 3D Al anodes for metallic-Al-based batteries by eliminating the problems of planar Al anodes and realizing the potential applications of aluminum-graphite batteries.

Generalized flyby trajectories around elongated minor celestial bodies as a rotating mass dipole

The aim of this paper is to understand the common characteristics of the generalized flyby trajectory around natural elongated bodies. Such flyby trajectories provide a short-term mechanism to clear away vicinal objects or temporally capture ejecta into circling orbits. The gravitational potential of elongated bodies is described by a unified approximate model, i.e., the rotating mass dipole which is two point masses connected with a constant massless rod The energy power is used to illustrate the flyby effect in terms of the instantaneous orbital energy. The essential of the single flyby trajectory is studied analytically, and the relationship between the flyby trajectory and its Jacobi integral is also illustrated. Sample trajectories are given to show the variational trend of the energy increment with respect to differen orbital periapsides. The distribution of natural ejecting orbits is presented by varying the parameters of the approximate model.

Global climate governance in the new era:Potential of business actors and technological innovation

The United Nations Framework Convention on Climate Change(UNFCCC)has established a climate governance mechanism with intergovernmental negotiations among sovereign states as the core.After nearly 30 years,progress in combating climate change has remained very modest compared with the numerous challenges raised.The global climate governance has entered a new era,such that incorporating other factors into the governance process is timely.Therefore,the study emphasizes technological innovation and business actors in climate governance after the Paris Agreement.Technological innovation can provide effective solutions for combating climate change and has been a crucial driving force in climate governance's evolution.Business actors are significant because they are actual implementers of technological innovation and can apply different types of power and influence on climate governance processes at various levels.In summary,business actors,as well as technological innovation in line with governments and the UNFCCC governance frameworks,create a new potential for climate governance in the new era.

Low-thermal-budget Au-free ohmic contact to an ultrathin barrier AlGaN/GaN heterostructure utilizing a micro-patterned ohmic recess

A pre-ohmic micro-patterned recess process,is utilized to fabricate Ti/Al/Ti/TiN ohmic contact to an ultrathin-barrier(UTB)AlGaN/GaN heterostructure,featuring a significantly reduced ohmic contact resistivity of 0.56Ω·mm at an alloy temperature of 550℃.The sheet resistances increase with the temperature following a power law with the index of +2.58,while the specific contact resistivity decreases with the temperature.The contact mechanism can be well described by thermionic field emission(TFE).The extracted Schottky barrier height and electron concentration are 0.31 eV and 5.52×10^(18) cm^(−3),which suggests an intimate contact between ohmic metal and the UTB-AlGaN as well as GaN buffer.A good correlation between ohmic transfer length and the micro-pattern size is revealed,though in-depth investigation is needed.A preliminary CMOS-process-compatible metal-insulator-semiconductor high-mobility transistor(MIS-HEMT)was fabricated with the proposed Au-free ohmic contact technique.

Simultaneous utilization of electro-generated O_(2)and H_(2)for H_(2)O_(2)production:An upgrade of the Pd-catalytic electro-Fenton process for pollutants degradation

The Electro-Fenton(EF)process is one of the promising advanced oxidation processes(AOPs)for environmental remediation.The H_(2)O_(2) yield of EF process largely determines its performance on organic pollutants degradation.Conventional Pd-catalytic EF process generates H_(2)O_(2) via the combination reaction of anodic O_(2) and cathodic H;.However,the relatively expensive catalyst limits its application.Herein,a hybrid Pd/activated carbon(Pd/AC)-stainless steel mesh(SS)cathode(PACSS)was proposed,which enables more efficie nt H_(2)O_(2)generation.It utilizes AC,the support of Pd catalyst,as part of cathode for H_(2)O_(2) generation via 2-electron anodic O_(2) reduction,and SS serve as a current distributor.Moreover,H_(2)O_(2) could be catalytically decomposed upon AC to generate highly reactive·OH,which avoids the use of Fe;.Compared with conventional Pd catalyst,H_(2)O_(2) concentration obtained by PACSS cathode is248.2%higher,the O_(2)utilization efficiency was also increased from 3.2%to 10.8%.Within 50 min,26.3%,72.5%,and 94.0%H_(2)O_(2) was decomposed by Pd,AC,and Pd/AC.Fluorescence detection results implied that Pd/AC is effective upon H_(2)O_(2) activation for·OH generation.Finally,iron-free EF process enabled by PACSS cathode was examined to be effective for reactive blue 19(RB19)degradation.After continuous running for 10 cycles(500 min),the PACSS cathode was still stable for H_(2)O_(2)generation,H_(2)O_(2)activation,and RB19 degradation,showing its potential application for organic pollutants degradation without increase in the running cost.

New insight into polystyrene ion exchange resin for efficient cesium sequestration:The synergistic role of confined zirconium phosphate nanocrystalline

Polystyrene resins(PS)have been practical ion exchangers for radionuclides removal from water.However,nonspecific effects of ion exchange groups continue to be a major obstacle for emergency treatment with coexisting ions of high concentrations.The selectivity for Cs+enables zirconium phosphate(ZrP)to be the most promising inorganic sorbent for radioactive cesium extraction,despite being difficult to synthesize and causing excessive pressure loss in fixed-bed reactors due to fine powder.Herein,through facile confined crystallization in host macropores,we prepared PS confinedα-ZrP nanocrystalline(ZrP-PS).Size-screen sorption of layeredα-ZrP and sulfonic acid group preconcentration of PS synergistically enable a considerably higher Cs+affinity of ZrP-PS than PS,as confirmed by X-ray photoelectron spectroscopy(XPS)analysis.ZrP-PS demonstrated remarkable cesium sequestration performance in both batch and continuous experiments,with a high adsorption capacity of 269.58 mg/g,a rapid equilibrium within 80 min,and a continuous effluent volume of 2300 L/kg sorbents.Given the excellent selectivity for Cs+and flexibility to separate from treated water,ZrP-PS holds great promise as purification packages for the emergency treatment of radioactively contaminated water.

Multiple SiGe/Si layers epitaxy and SiGe selective etching for vertically stacked DRAM

Fifteen periods of Si/Si_(0.7)Ge_(0.3)multilayers(MLs)with various Si Ge thicknesses are grown on a 200 mm Si substrate using reduced pressure chemical vapor deposition(RPCVD).Several methods were utilized to characterize and analyze the ML structures.The high resolution transmission electron microscopy(HRTEM)results show that the ML structure with 20 nm Si_(0.7)Ge_(0.3)features the best crystal quality and no defects are observed.Stacked Si_(0.7)Ge_(0.3)ML structures etched by three different methods were carried out and compared,and the results show that they have different selectivities and morphologies.In this work,the fabrication process influences on Si/Si Ge MLs are studied and there are no significant effects on the Si layers,which are the channels in lateral gate all around field effect transistor(L-GAAFET)devices.For vertically-stacked dynamic random access memory(VS-DRAM),it is necessary to consider the dislocation caused by strain accumulation and stress release after the number of stacked layers exceeds the critical thickness.These results pave the way for the manufacture of high-performance multivertical-stacked Si nanowires,nanosheet L-GAAFETs,and DRAM devices.

Charge-mediated voltage modulation of magnetism in Hf_(0.5)Zr_(0.5)O_(2)/Co multiferroic heterojunction

We construct the Hall-bar device with the size of several hundred nanometers based on the HZO/Co multiferroic heterojunction. A remarkable voltage-controlled magnetism is observed in the device that possesses both ferroelectric property and perpendicular magnetic anisotropy(PMA). The nucleation field and coercivity can be modulated by voltage pulse while saturation field keeps stable. The non-volatile and reversible voltage-controlled magnetism is ascribable to interfacial charges caused by ferroelectric polarization. Meanwhile, the effective anisotropy energy density(Ku) can also be controlled by voltage pulse, a decrease of 83% and increase of 28% in Kuare realized under-3-V and 3-V pulses,respectively. Because the energy barrier is directly proportional to Ku under a given volume, a decreased or enhanced energy barrier can be controlled by voltage pulse. Thus, it is an effective method to realize low-power and high-stability magneto-resistive random-access memory(MRAM).

Single-Component Color-Tunable Smart Organic Emitters with Simultaneous Multistage Stimuli-Responsiveness and Multimode Emissions

Achieving color-tunable emission in single-component organic emitters with multistage stimuli-responsiveness is of vital significance for intelligent optoelectronic applications,but remains enormously challenging.Herein,we present an unprecedented example of a color-tunable single-component smart organic emitter(DDOP)that simultaneously exhibits multistage stimuli-responsiveness and multimode emissions.DDOP based on a highly twisted amide-bridged donor-tcceptor-donor structure has been found to facilitate intersystem crossing,form multimode emissions,and generate multiple emissive species with multistage stimuli-responsiveness.DDOP pristine crystalline powders exhibit abnormal excitation-dependent emissions from a monomer-dominated blue emission centered at 470 nm to a dimer-dominated yellow emission centered at 550 nm through decreasing the ultraviolet(UV)excitation wavelengths,whereas DDOP single crystals show a wide emission band with a main emission peak at 585 nm when excited at different wavelengths.The emission behaviors of pristine crystalline powders and single crystals are different,demonstrating emission features that are closely related to the aggregation states.The work has developed color-tunable single-component organic emitters with simultaneous multistage stimuli-responsiveness and multimode emissions,which is vital for expanding intelligent optoelectronic applications,including multilevel information encryption,multicolor emissive patterns,and visual monitoring of UV wavelengths.

肿瘤放疗中塑形垫结合热塑网膜体位固定方式的摆位误差研究

目的:探究塑形垫结合热塑网膜体位固定方法在放疗过程中较单一热塑网膜或真空垫固定方法能否减少摆位误差。方法:分析2018年1月至2019年12月于湘雅常德医院接受放疗的头颈和胸腹肿瘤患者66例,其中头颈肿瘤患者27例、胸腹肿瘤患者39例。15例头颈肿瘤患者使用头颈肩热塑面罩固定(A组),12例使用塑形垫结合头颈肩热塑面罩固定(B组);19例胸腹肿瘤患者使用真空垫固定(A组),20例使用塑形垫结合热塑体膜固定(B组)。对所有患者实施锥形束CT扫描,统计配准后得到左右(left-right,LR)、头脚(superior-inferior,SI)和腹背(anterior-posterior,AP)方向及旋转角度摆位误差值,分析不同体位固定方式间的摆位误差大小。结果:对于头颈肿瘤患者,B组在LR、SI以及旋转角度误差分别为(0.06±0.06)cm、(0.08±0.07)cm、(0.12±0.17)°,小于A组的摆位误差(0.10±0.11)cm、(0.13±0.14)cm、(0.25±0.47)°,差异具有统计学意义(P<0.05),AP摆位误差差异无统计学意义(P>0.05);对于胸腹部肿瘤患者,B组在LR和旋转角度误差分别为(0.10±0.08)cm、(0.09±0.18)°,小于A组摆位误差(0.14±0.12)cm、(0.22±0.39)°,差异具有统计学意义(P<0.05),在SI和AP摆位误差差异无统计学意义(P>0.05)。结论:在头颈肿瘤和胸腹肿瘤患者放疗过程中使用塑形垫结合热塑网膜的体位固定方式相比于其他单一体位固定方式而言,能够提升患者体位的重复性、稳定性,减少摆位误差。

A New Method of Wind Turbine Bearing Fault Diagnosis Based on Multi-Masking Empirical Mode Decomposition and Fuzzy C-Means Clustering

Based on Multi-Masking Empirical Mode Decomposition (MMEMD) and fuzzy c-means (FCM) clustering, a new method of wind turbine bearing fault diagnosis FCM-MMEMD is proposed, which can determine the fault accurately and timely. First, FCM clustering is employed to classify the data into different clusters, which helps to estimate whether there is a fault and how many fault types there are. If fault signals exist, the fault vibration signals are then demodulated and decomposed into different frequency bands by MMEMD in order to be analyzed further. In order to overcome the mode mixing defect of empirical mode decomposition (EMD), a novel method called MMEMD is proposed. It is an improvement to masking empirical mode decomposition (MEMD). By adding multi-masking signals to the signals to be decomposed in different levels, it can restrain low-frequency components from mixing in highfrequency components effectively in the sifting process and then suppress the mode mixing. It has the advantages of easy implementation and strong ability of suppressing modal mixing. The fault type is determined by Hilbert envelope finally. The results of simulation signal decomposition showed the high performance of MMEMD. Experiments of bearing fault diagnosis in wind turbine bearing fault diagnosis proved the validity and high accuracy of the new method.

AN UPBOUND OF HAUSDORFF’S DIMENSION OF THE DIVERGENCE SET OF THE FRACTIONAL SCHRODINGER OPERATOR ON H^(s)(R^(n))

Given n≥2 and α≥1/2,we obtained an improved upbound of Hausdorff's dimension of the fractional Schrodinger operator;that is,supf∈H^(s)(R^(n)) dim_(H){x∈R^(n):limt→0 e^(it)(-△)^(α) f(x)≠f(x)}≤n+1-2(n+1)s/n for n/2(n+1)<s≤n/2.

PI force feedback control for large flexible structure vibration with active tendons

Active tendon, consisting of a displacement actuator and a collocated force sensor, was first presented by Preumont and his co-workers to attenuate the vibration of large flexible space structures, and the control algorithm adopted by them was integral force feedback. This paper presents a new proportional-integral （PI） force feedback algorithm to achieve larger damping ratios for the structure without the requirement of structure model. Stability of the control system is shown, and simulations of a structure similar to JPL-MPI demonstrate the effectiveness of the proposed algorithm for vibration control of space structures.

Preface:Orbits around asteroid

One of the core issues in modern celestial mechanics is the orbital dynamics in the near-regime gravitational field of as- teroids, which provides deep insights into the mathematical nature of a class of nonlinear systems, and plays as a critical basis for in situ explorations of different science goals. Lots of efforts have been made to reveal the characteristics of orbital motion in the vicinity of asteroids, and to improve the skills of asteroid research in methodology.

Imaging pancreatic islet cells by positron emission tomography

It was estimated that every year more than 30000 persons in the United States- approximately 80 people per day- are diagnosed with type 1 diabetes(T1D). T1 D is caused by autoimmune destruction of the pancreatic islet(β cells) cells. Islet transplantation has become a promising therapy option for T1 D patients, while the lack of suitable tools is difficult to directly evaluate of the viability of the grafted islet over time. Positron emission tomography(PET) as an important non-invasive methodology providing high sensitivity and good resolution, is able to accurate detection of the disturbed biochemical processes and physiological abnormality in living organism. The successful PET imaging of islets would be able to localize the specific site where transplanted islets engraft in the liver, and to quantify the level of islets remain alive and functional over time. This information would be vital to establishing and evaluating the efficiency of pancreatic islet transplantation. Many novel imaging agents have been developed to improve the sensitivity and specificity of PET islet imaging. In this article, we summarize the latest developments in carbon-11, fluorine-18, copper-64, and gallium-68 labeled radioligands for the PET imaging of pancreatic islet cells.