Enhancing Na^(+) diffusion dynamics and structural stability of O3-NaMn_(0.5)Ni_(0.5)O_(2)cathode by Sc and Zn dual-substitution

Sc and Zn were introduced into O3-NaMn_(0.5)Ni_(0.5)O_(2)(NaMN)using the combination of solution combustion and solid-state method.The effect of Sc and Zn dual-substitution on Na^(+) diffusion dynamics and structural stability of NaMN was investigated.The physicochemical characterizations suggest that the introduction of Sc and Zn broaden Na^(+) diffusion channels and weaken the Na—O bonds,thereby facilitating the diffusion of sodium ions.Simulations indicate that the Sc and Zn dual-substitution decreases the diffusion barrier of Na-ions and improves the conductivity of the material.The dual-substituted NaMn_(0.5)Ni_(0.4)Sc_(0.04)Zn_(0.04)O_(2)(Na MNSZ44)cathode delivers impressive cycle stability with capacity retention of 71.2%after 200 cycles at 1C and 54.8%after 400 cycles at 5C.Additionally,the full cell paired with hard carbon anode exhibits a remarkable long-term cycling stability,showing capacity retention of 64.1%after 250 cycles at 1C.These results demonstrate that Sc and Zn dual-substitution is an effective strategy to improve the Na^(+) diffusion dynamics and structural stability of NaMN.

“互联网+”时代背景下炎症性肠病患者的心理问题及干预研究述评

炎症性肠病(inflammatory bowel diseases,IBD)是一种慢性非特异性肠道炎症性疾病,发病机理尚未清楚,但目前已证实心理因素与IBD发生、发展和疾病结局等密切相关.本文就“互联网+”时代背景下IBD患者存在的心理问题和心理干预状况进行分析.

炎症性肠病患者自我效能研究

炎症性肠病是一种慢性、反复发作、不可治愈的肠道疾病,易给患者带来沉重的身心损害,而自我效能是影响身心健康的重要因素.本文对炎症性肠病患者自我效能进行分析,重点介绍炎症性肠病患者自我效能测量工具、影响因素、对患者影响及改善措施,旨在为以后开展相关研究提供参考.

Effects of particle size and content of RDX on burning stability of RDXbased propellants

Particle size and content of RDX are the two main factors that affect the burning stability of RDX-based propellants. However, these effects and the corresponding mechanisms are still controversial. In this work, we investigated the physicochemical processes during burning and the corresponding mechanisms through the technologies of structure compactness analysis on the base of voidage measurement and theoretical interfacial area estimation, apparent burning rate measurement using closed vessel(CV)and extinguished burning surface characterization relying on interrupted closed vessel(ICV) and scanning electron microscope(SEM). The results indicate that the voidage increased with the increase of RDX content and particle size due to the increasing interfacial area and increasing interface gap size,respectively. The apparent burning rate increased with the increase of RDX particle size because of the decreasing RDX specific surface area on the burning surface, which could decrease the heat absorbing rates of the melting and evaporation processes of RDX in the condensed phase. Similarly, the apparent burning rate decreased with the increase of RDX content at pressures lower than around 55 MPa due to the increasing RDX specific surface area. Whereas, an opposite trend could be observed at pressures higher than around 55 MPa, which was attributed to the increasing heat feedback from the gas phase as the result of the increasing propellant energy. For propellants containing very coarse RDX particles, such as 97.8 and 199.4 μm average size, the apparent burning rate increased stably with a flat extinguished surface at pressures lower than around 30 MPa, while increased sharply above around 30 MPa with the extinguished surface becoming more and more rugged as the pressure increased. In addition, the turning degree of u-p curve increased with the increase of coarse RDX content and particle size, and could be reduced by improving the structure compactness.

Effect of growth rate on microstructure and microhardness of directionally solidified Ti-44Al-5Nb-1.5Cr-1.5Zr-1Mo-0.1B alloy

The effect of growth rates (V=2-50 μm·s-1) on microstructure and microhardness of directionally solidified Ti-44Al-5Nb-1.5Cr-1.5Zr-1Mo-0.1B (at.%) alloy at a constant temperature gradient (G=18 K·mm-1) was investigated. Results indicated that β phase was the primary phase of the directionally solidified Ti-44Al-5Nb-1.5Cr-1.5Zr-1Mo-0.1B alloy. As the growth rate increases, the solid/liquid interface turns from cellular growth to dendric growth. The interlamellar spacing (λs) decreases with the increase of growth rate according to the relationship of λs=3.39V -0.31. The solidification segregation occurs due to the enrichment of β-stabilizing element Nb, Cr in primary β phase during solidification;moreover, the degree of the segregation increases with the growth rate, resulting in the emergence of B2 phase in lamellar colonies at high growth rates. The microhardness (Hv) grows with the growth rate based on the equation of HV=328.69V 0.072, which mainly attributes to the microstructure refinement.

A New Effect of Oxygen Plasma on Two-Dimensional Field-Effect Transistors:Plasma Induced Ion Gating and Synaptic Behavior

Plasma treatment is a powerful tool to tune the properties of two-dimensional materials. Previous studies have utilized various plasma treatments on two-dimensional materials. We find a new effect of plasma treatment. After controlled oxygen-plasma treatment on field-effect transistors based on two-dimensional SnSe2, the capacitive coupling between the silicon back gate and the channel through the 300 nm SiO2 dielectric can be dramatically enhanced by about two orders of magnitude(from 11 n F/cm^2 to 880 nF/cm^2), reaching good efficiency of ionliquid gating. At the same time, plasma treated devices show large hysteresis in the gate sweep demonstrating memory behavior. We reveal that this spontaneous ion gating and hysteresis are achieved with the assistance of a thin layer of water film automatically formed on the sample surface with water molecules from the ambient air, due to the change in hydrophilicity of the plasma treated samples. The water film acts as the ion liquid to couple the back gate and the channel. Thanks to the rich carrier dynamics in plasma-treated two-dimensional transistors, synaptic functions are realized to demonstrate short-and long-term memories in a single device. This work provides a new perspective on the effects of plasma treatment and a facile route for realizing neuromorphic devices.

Standing-wave spectrometry in silicon nano-waveguides using reflection-based near-field scanning optical microscopy

Utilizing reflection-based near-field scanning optical microscopy(NSOM) to image and analyze standing-wave patterns, we present a characterization technique potentially suitable for complex photonic integrated circuits. By raster scanning along the axis of a straight nano-waveguide in tapping mode and sweeping wavelength, detailed information of propagating waves in that waveguide has been extracted from analyses in both space and wavelength domains. Our technique needs no special steps for phase stabilization, thus allowing long-duration and environment-insensitive measurements. As a proof-of-concept test, in a silicon single-mode waveguide with a few of etched holes, the locations and reflection strengths of the inner defects have been quantified. The measurement uncertainty of the reflection amplitude is less than 25% at current stage. Our technique paves the way for non-destructively diagnosing photonic circuits on a chip with sub-wavelength spatial resolution and detailed information extraction.

Particle–hole fluctuations and possible superconductivity in doped α-RuCl_3

We study various particle–hole excitations and possible superconducting pairings mediated by these fluctuations in doped α-RuCl_3 by using multi-band Hubbard model with all t_(2g) orbitals. By performing a random-phase-approximation(RPA) analysis, we find that among all particle–hole excitations, the j_(eff)= 1/2 pseudospin fluctuations are dominant, suggesting the robustness of j_(eff)= 1/2 picture even in the doped systems. We also find that the most favorable superconducting state has a d-wave pairing symmetry.

An association study of HFEgene mutation with idiopathic male infertility in the Chinese Han population

Mutations in the haemochromatosis gene （HFE） influence iron status in the general population of Northern Europe, and excess iron is associated with the impairment of spermatogenesis. The aim of this study is to investigate the association between three mutations （C282Y, H63D and S65C） in the HFEgene with idiopathic male infertility in the Chinese Han population. Two groups of Chinese men were recruited： 444 infertile men （including 169 with idiopathic azoospermia） and 423 controls with proven fertility. The HFEgene was detected using polymerase chain reaction-restriction fragment length polymorphism （PCR-RFLP） technique. The experimental results demonstrated that no C282Y or $65C mutations were detected. Idiopathic male infertility was not significantly associated with heterozygous H63D mutation （odds ratio=O.801, 95% confidence interval=0.452-1.421, X2=0.577, P=0.448）. The H63D mutation frequency did not correlate significantly with the serum luteinizing hormone （LH）, follicle-stimulating hormone （FSH） and testosterone （T） levels in infertile men （P=0.896, P=0.404 and P=O.05, respectively）. Our data suggest that the HFEH63D mutation is not associated with idiopathic male reproductive dysfunction.

Impact of laser scanning speed on microstructure and mechanical properties of Inconel 718 alloys by selective laser melting

Inconel 718 alloys were fabricated by selective laser melting under different scanning speeds to investigate the change of the morphology of molten pool,direction of grain growth,and tensile properties.Results show that as the scanning speed increases from 1,000 to 1,450 mm·s^(-1),the ratio between depth and width of molten pool increases,yet their overlapping regimes decrease.Meanwhile,increasing scanning speed can promote the solidified structure evolve from cell to columnar dendrites,and decrease the dendrite spacing from 0.54 to 0.39 μm;the average columnar grain size also decreases from 84.42 to 73.51 μm.At different scanning speeds,the preferred orientation of grains along the building is mainly <001> direction.In addition,the tensile properties of samples under different scanning speeds present a non-monotonic transition.The maximum ultimate tensile strength and elongation can reach 1,014±19 MPa and 19.04±1.12 (%),respectively,at the scanning speed of 1,300 mm·s^(-1).

Three-Body Recombination of Cold^(3)He–^(3)He–T^(-)System

The atom-atom-anion three-body recombination(TBR)and collision induced dissociation(CID)processes of the^(3)He-^(3)He-T^(-)system at ultracold temperatures are investigated by solving the Schr¨odinger equation in the adiabatic hyperspherical representation.The variations of the TBR and CID rates with the collision energies in the ultracold temperatures are obtained.It is found that the J~Π=1~-symmetry dominates the TBR and CID processes in most of the considered collision energy range.The rate of TBR(CID)into(from)the l=1 anion is larger than those for the l=0 and l=2 anions,with the l representing the rotational quantum number of~3HeT~-.This can be understood via the nonadiabatic couplings among the different channels.

Hydrogen-induced amorphization of Zr-Cu-Ni-Al alloy

Arc melting was utilized in this study to produce Zr_(55)Cu_(30)Ni_5Al_(10) alloys under mixed atmospheres with various ratios of high-purity hydrogen to argon. The influences of hydrogen addition on the solidification structure and glass-forming ability of Zr_(55)Cu_(30)Ni_5Al_(10) alloy were determined by examining microstructures in different parts of the cast ingots. The results showed that different degrees of crystallization structures were obtained in the ascast button ingots after arc melting in high-purity Ar, and the cross-sectional solidification morphology of arcmelted ingots was found to consist of crystals with varying from the bottom up. By contrast, there were completely amorphous structures in the middle and upper areas of the as-cast button ingots fabricated by adding 10% H_2 to the high-purity Ar atmosphere. A clear solidification interface was found between the crystal and glass in the ascast button ingots, which indicates that hydrogen addition can enhance the Zr_(55)Cu_(30)Ni_5Al_(10) alloy's glass-forming ability. The precise mechanism responsible for this was also investigated.

Disaster effects of climate change in High Mountain Asia:State of art and scientific challenges Disaster effects of climate change in High Mountain Asia:State of art and scientific challenges

High Mountain Asia(HMA)shows a remarkable warming tendency and divergent trend of regional precipitation with enhanced meteorological extremes.The rapid thawing of the HMA cryosphere may alter the magnitude and frequency of nature hazards.We reviewed the influence of climate change on various types of nature hazards in HMA region,including their phenomena,mechanisms and impacts.It reveals that:1)the occurrences of extreme rainfall,heavy snowfall,and drifting snow hazards are escalating;accelerated ice and snow melting have advanced the onset and increased the magnitude of snowmelt floods;2)due to elevating trigger factors,such as glacier debuttressing and the rapid shift of thermal and hydrological regime of bedrock/snow/ice interface or subsurface,the mass flow hazards including bedrock landslide,snow avalanche,ice-rock avalanches or glacier detachment,and debris flow will become more severe;3)increased active-layer detachment and retrogressive thaw slumps slope failures,thaw settlement and thermokarst lake will damage many important engineering structures and infrastructure in permafrost region;4)multi-hazards cascading hazard in HMA,such as the glacial lake outburst flood(GLOF)and avalanche-induced mass flow may greatly enlarge the destructive power of the primary hazard by amplifying its volume,mobility,and impact force;and 5)enhanced slope instability and sediment supply in the highland areas could impose remote catastrophic impacts upon lowland regions,and threat hydropower security and future water shortage.In future,ongoing thawing of HMA will profoundly weaken the multiple-phase material of bedrock,ice,water,and soil,and enhance activities of nature hazards.Compounding and cascading hazards of high magnitude will prevail in HMA.As the glacier runoff overpasses the peak water,low flow or droughts in lowland areas downstream of glacierized mountain regions will became more frequent and severe.Addressing escalating hazards in the HMA region requires tackling scientific challenges,including understanding multiscale evolution and formation mechanism of HMA hazard-prone systems,coupling thermo‒hydro‒mechanical processes in multi-phase flows,predicting catastrophes arising from extreme weather and climate events,and comprehending how highland hazards propagate to lowlands due to climate change.

Chemical Composition Effect on Microstructures and Mechanical Properties in Friction Stir Additive Manufacturing

The variation of chemical compositions can affect the mechanical property of friction stir additive manufacturing(FSAM).Quantitative characterization of the relationship between the chemical composition and the mechanical property of FSAM components is key to control the quality of FSAM components.The effect of chemical composition on the mechanical property of 6 xxx series aluminum alloy FSAM joint was studied by both experimental and numerical methods.A moving heat source model was established to simulate the heat transfer in FSAM process.The average grain size was calculated by Monte Carlo model,and the precipitate evolution model was used to calculate the hardness and constitutive stress-strain relationship.The validity of the numerical model was verified by experiments.Results indicate that the hardness and yield stress of 6 xxx series aluminum alloy FSAW joint can be enhanced by increasing silicon or magnesium contents.By increasing the content of magnesium(silicon),the volume fraction and the mean radius of MgSi can be increased when the content of silicon(magnesium) is excessive.With the decrease in volume fraction,the average grain size can be increased.By changing the weight percentage of magnesium and silicon in different layers,the hardness and yield stress along the build direction can be controlled.

Thickness modulation effect of CeO_2 layer for YBCO films grown by pulsed laser deposition

CeO2 film plays an essential role in nucleation and growth of YBa2 Cu3 O（7-x）（YBCO） films. In this work,the dependence of superconducting properties of YBCO on CeO2 films with different thicknesses was investigated,in order to achieve fabrication of high-performance YBCO coated conductors in industrial scale. The crystalline structure and morphology of CeO2 films with thickness ranging from 21 to 563 nm were systematically characterized by means of X-ray diffraction（XRD）, atomic force microscope（AFM） and reflection high-energy electron diffraction（RHEED）. Additional focus was addressed on evolution of the surface quality of CeO2 films with thickness increasing. The results show that at the optimal thickness of 221 nm, CeO2 film exhibits sharp in-plane and out-of-plane texture with full width of half maximum（FWHM） values of 5.9° and 1.8°, respectively, and smooth surface with a mean root-mean-square（RMS） roughness value as low as 0.6 nm. Combing RHEED and transmission electron microscope（TEM） cross-sectional analysis, it is found that nucleation and growth of CeO2 films at early stage remain in island growth mode with rougher surface,while further increasing the thickness beyond the optimal thickness leads to weak surface quality, consequently resulting in degradation of superconductor layers deposited subsequently. Eventually, a critical current density（Jc） as high as 4.6×10-6 A·cm-（-2）（77 K, self-field） is achieved on a YBCO film on a thickness-modulated CeO2/MgO/Y2 O3/Al2 O3/C276 architecture, demonstrating the advantages of CeO2 films as buffer layer in high-throughput manufacture of coated conductors.

Discovery of CCDC188 gene as a novel genetic target for human acephalic spermatozoa syndrome

Dear Editor,Male infertility is a widespread health problem and affects approximately 6%–8%of the male population(Jiao et al.,2021).Acephalic spermatozoa syndrome(ASS),a rare but severe type of teratozoospermia,is characterized by decapitated flagella in the semen and it finally leads to male infertility(Yuan et al.,2015).