Cooperative structure of Li/Ni mixing and stacking faults for achieving high-capacity Co-free Li-rich oxides

Co-free Li-rich layered oxides(LLOs)are emerging as promising cathode materials for Li-ion batteries due to their low cost and high capacity.However,they commonly face severe structural instability and poor electrochemical activity,leading to diminished capacity and voltage performance.Herein,we introduce a Co-free LLO,Li_(1.167)Ni_(0.222)Mn_(0.611)O_(2)(Cf-L1),which features a cooperative structure of Li/Ni mixing and stacking faults.This structure regulates the crystal and electronic structures,resulting in a higher discharge capacity of 300.6 mA h g^(-1)and enhanced rate capability compared to the typical Co-free LLO,Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2)(Cf-Ls).Density functional theory(DFT)indicates that Li/Ni mixing in LLOs leads to increased Li-O-Li configurations and higher anionic redox activities,while stacking faults further optimize the electronic interactions of transition metal(TM)3d and non-bonding O 2p orbitals.Moreover,stacking faults accommodate lattice strain,improving electrochemical reversibility during charge/discharge cycles,as demonstrated by the in situ XRD of Cf-L1 showing less lattice evolution than Cf-Ls.This study offers a structured approach to developing Co-free LLOs with enhanced capacity,voltage,rate capability,and cyclability,significantly impacting the advancement of the next-generation Li-ion batteries.

Neutronics analysis of a stacked structure for a subcritical system with LEU solution driven by a D-T neutron source for~(99)Mo production

The utilization of neutrons markedly affects the medical isotope yield of a subcritical system driven by an external D-T neutron source.The general methods to improve the utilization of neutrons include moderating multiplying,and reflecting neutrons,which ignores the use of neutrons that backscatter to the source direction.In this study,a stacked structure was formed by assembling the multiplier and the low-enriched uranium solution to enable the full use of neutrons that backscatter to the source direction and further improve the utilization of neutrons.A model based on SuperMC was used to evaluate the neutronics and safety behavior of the subcritical system,such as the neutron effective multiplication factor,neutron energy spectrum,medical isotope yield,and heat deposition.Based on the calculation results,when the intensity of the neutron source was 59×10^(13)n/s,the optimized design with a stacked structure could increase the yield of ^(99)Mo to182 Ci/day,which is approximately 16% higher than that obtained with a single-layer structure.The inlet H_(2)O coolant velocity of 1.0 m/s and initial temperature of 20℃ were also found to be sufficient to prevent boiling of the fuel solution.

Stacked Structure Improves Output Reproducibility of Rubber Force Sensor

The electricity-conducting rubber force sensor is an attractive candidate as a low-cost material for tactile sensors. This article shows the evidence that the output reproducibility is largely improved when two identical sheets of the sensors are stacked. The stacked structure may reduce accidental error that is a fatal obstacle in an accurate control system.

Numerical Simulation Investigation on Split Sleeve Cold Expansion of Ti-Al Stacked Structure

Split sleeve cold expansion(SSCX)can efiectively enhance fatigue life of holes by improving the field of residual stress.Numerical simulations were conducted to investigate the parameter influence mechanism and obtain higher compressive residual stress(CRS).Expansion method,degree of cold expansion(DCE),friction coefficient between laminations and depth-diameter ratio were analyzed.For Ti-Al stacked joint holes,two expansion methods are proposed,namely aluminum alloy first followed titanium alloy(Al first)and titanium alloy first followed aluminum alloy(Ti first).The results show that expansion method and DCE have significant efiects on the field of circumferential residual stress,and the friction has a negligible influence.A higher value of CRS and a wider layer of plastic deformation are induced with Ti first.Optimal DCE of TiAl stacked structure is 5.2%-5.6%.As the depth-diameter ratio is in the range of 0.5-1.25,a positive linear correlation between the maximum compressive residual stress(CRS_(max))and depth-diameter ratio is shown.

Microstructure and mechanical properties of Mg_(94)Zn_2Y_4 extruded alloy with long-period stacking ordered structure

The microstructure and mechanical properties of Mg94Zn2Y4 extruded alloy containing long-period stacking ordered structures were systematically investigated by SEM and TEM analyses. The results show that the 18R-LPSO structure and α-Mg phase are observed in cast Mg94Zn2Y4 alloy. After extrusion, the LPSO structures are delaminated and Mg-slices with width of 50-200 nm are generated. By ageing at 498 K for 36 h, the ageing peak is attained andβ′phase is precipitated. Due to this novel precipitation, the microhardness ofα-Mg matrix increases apparently from HV108.9 to HV129.7. While the microhardness for LPSO structure is stabilized at about HV145. TEM observations and SAED patterns indicate that the β′ phase has unique orientation relationships betweenα-Mg and LPSO structures, the direction in the close-packed planes ofβ′precipitates perpendicular to that ofα-Mg and LPSO structures. The ultimate tensile strength for the peak-aged alloy achieves 410.7 MPa and the significant strength originates from the coexistence ofβ′precipitates and 18R-LPSO structures.

Characteristic of Intelligent Air Bag Venting Structure Actuating by Electrostrictive Stack Actuator

In this paper the conception of smart materials and structures is firstly combined with research of air bag,and the main theory of self adapting cushioning of intelligent air bag is expatiated.The intelligent venting structure is the main part affecting the cushioning result.Electrostrictive material was found having big force,high response speed and wide linearity,and it is fit to utilize in intelligent venting structure. The characteristic of the dynamic response and cushioning actuating of an electrostrictive stack actuator is analyzed,and the result of the computer simulation of the fuzzy control to intelligent venting structure is given.It is concluded that intelligent venting structure has good actuating characteristic and can satisfy the need of intelligent air bag.

Long-period stacking ordered structures in Mg-3Cu-1Mn-2Zn-1Y damping alloy

14H, 18R and 24R long-period stacking ordered （LPSO） structures were observed in the as-cast Mg-3Cu-1Mn-2Zn-1Y damping alloy using transmission electron microscopy （TEM）. These LPSO structures contained Mg, Y, Cu and Zn and thus they were quaternary phases. Sharp diffraction pattern of the 24R structure was obtained and the angle between and g10024R was measured to be 5.03°. During high resolution TEM observations, lattice fringes with two characteristic spacings were observed within the 24R structure. Based on the experimental results, 6H, 7H and three 8H are suggested as the building blocks of 18R, 14H and 24R structures, respectively. The 24R unit cell can be interpreted as the stacking of 8H building blocks in the same shear direction with a shear angle of about 5.03°. The imperfect 24R structures are in order or disorder arrangements of principal 8H and minor 6H blocks. This double-block structure model is also applicable to other reported defects in LPSO structures.

A Warming Structure for Piezoelectric Stack Working in Cryogenic Temperature

It is widely acknowledged that the performance of a piezoelectric stack would decline with the temperature decreasing,which will exert negative influence on its application in low-temperature environment.Therefore,a convenient and efficient warming structure for the piezoelectric stack is proposed in this paper to solve this problem.Based on the theoretical analysis of heat transfer,two heating modes,namely,overall heating and local heating are analyzed and compared.Moreover,experimental tests are conducted to evaluate the effectiveness of the structure.Based on the results,it can be concluded that the theoretical results are confirmed with experimental results.Besides,the temperature and performance of the piezoelectric stack are kept stable as temperature varies from 10℃to-70℃,which manifests the feasibility of the structure.Therefore,this paper could be an available reference for those engaged in cryogenic investigation of smart materials and structures.

Stacking fault energy and electronic structure of molybdenum under solid solution softening/hardening

Ab initio calculations are used to understand the fundamental mechanism of the solid solution softening/hardening of the Mo-binary system.The results reveal that the Mo-Ti,Mo-Ta,Mo-Nb,and Mo-W interactions are primarily attractive with negative heats of formation,while the interactions of Mo-Re,and Mo-Zr would be mainly repulsive with positive heats of formation.It is also shown that the addition of Re and Zr would cause the solid solution softening of Mo by the decrease of the unstable stacking fault energy and the increase of ductility.On the contrary,the elements of W,Ta,Ti,and Nb could bring about the solid-solution hardening of Mo through the impediment of the slip of the dislocation and the decrease of ductility.Electronic structures indicate that the weaker/stronger chemical bonding due to the alloying elements should fundamentally induce the solid solution softening/hardening of Mo.The results are discussed and compared with available evidence in literatures,which could deepen the fundamental understanding of the solid solution softening/hardening of the binary metallic system.

Review on long-period stacking-ordered structures in Mg-Zn-RE alloys

The recent development of high-strength magnesium alloys is focused on the role of the strengthening phases with a novel long-period stacking-ordered (LPSO) structure. This review detailed the main factors influencing the formation of LPSO phases, including alloying ele-ments, preparation methods, and heat treatments. Furthermore, process control in structure types, formation and transformation behavior, strengthening and toughening mechanisms of the LPSO phase were discussed. Finally, the current problems and development trends of high-strength Mg-Zn-RE alloys were also put forward.

Effect of foundation flexibility on ductility reduction factors for R/C stack-like structures

The most important parameter used to determine force reduction factors in force-based design procedures adopted in the current seismic codes is the structural ductility. For a structure supported on a flexible foundation, the ductility factor could be affected by foundation compliances. The ductility factors given in the current codes are mostly assigned ignoring the effect of SSI and therefore the objective of this research is to assess the significance of SSI phenomenon on ductility factors of stack-like structures. The deformed configuration of stack-fike structures is idealized as an assemblage of beam elements considering nonlinear moment-curvature relations, while a linear sway-rocking model was implemented to model the supporting soil. Using a set of artificial records, repeated linear and nonlinear analyses were performed by gradually increasing the intensity of acceleration to a level where the first yielding of steel in linear and nonlinear analyses is observed and a level corresponding to the stack collapse in the nonlinear analysis. The difference between inelastic and elastic resistance in terms of displacement ductility factors has been quantified. The results indicate that foundation flexibility can decrease the ductility of the system and neglecting this phenomenon may lead to erroneous conclusions in the prediction of the seismic performance of flexibly-supported R/C stack-like structures.

Thermal-Mechanical Simulation and Analysis on Structural Caused Package Induced Stress in Stacked Chip Scale Package

Stacked chip scale package(SCSP) attracts more and more attentions in advanced packages application with light weight,thin and small size,high reliability,low power and high storage capability.However,more and more physical and electrical issues being caused by package-induced stress in SCSP were reported recently.The effect of structural factors,including die thickness,die attach film thickness,die attach film type,and spacer size on package induced stress,was investigated.Analyses were given based on simulation results and provide important suggestion for package design.

Thermal Stability Improved by π–π Stacking Interactions: Synthesis, Crystal Structure and Thermal Decomposition of Sodium Nitroformate

An energetic salt, sodium nitroformate （NaNF）, was synthesized and characterized by elemental analysis, IR and UV spectra, and its crystal structure was first determined by single crystal X-ray diffraction. The structure exhibits two types of π-π stacking interactions between the nitroformate anions, i e, the parallel-displaced and T-shaped confgurafions. Furthermore, the thermal decomposition mechanism was investigated by DSC, TG-DTG and FTIR techniques. The kinetic parameters of the thermal decomposition were also calculated by using Kissinger＇s and Ozawa-Doyle＇s methods. The results show that NaNF has a good thermal stability, which is attributed to the π-π stacking interactions.

Effect of long-period stacking ordered structure on very high cycle fatigue properties of Mg-Gd-Y-Zn-Zr alloys

Magnesium alloys with a long-period stacking ordered(LPSO)structure usually possess excellent static strength,but their fatigue behaviors are poorly understood.This work presents the effect of the LPSO structure on the crack behaviors of Mg alloys in a very high cycle fatigue(VHCF)regime.The LPSO lamellas lead to a facet-like cracking process along the basal planes at the crack initiation site and strongly prohibit the early crack propagation by deflecting the growth direction.The stress intensity factor at the periphery of the faceted area is much higher than the conventional LPSO-free Mg alloys,contributing higher fatigue crack propagation threshold of LPSO-containing Mg alloys.Microstructure observation at the facets reveals a layer of ultrafine grains at the fracture surface due to the cyclic contact of the crack surface,which supports the numerous cyclic pressing model describing the VHCF crack initiation behavior.

Microstructure and tribological behavior of Mg-Gd-Zn-Zr alloy with LPSO structure

A Mg-14.28Gd-2.44Zn-0.54Zr （mass fraction, %） alloy was prepared by conventional ingot metallurgy （I/M）. The microstructure differences in as-cast and solution-treated alloys were investigated. Sliding tribological behaviors of the as-cast and solution-treated alloys were investigated under oil lubricant condition by pin-on-disc configuration. The wear loss and friction coefficients were measured at a load of 40 N and sliding speeds of 30-300 mm/s with a sliding distance of 5000 m at room temperature. The results show that the as-cast alloy is mainly composed ofα-Mg solid solution, the lamellar 14H-type long period stacking ordered （LPSO） structure within matrix, andβ-[（Mg,Zn）3Gd] phase. However, most of theβ-phase transforms to X-phase with 14H-type LPSO structure after solution heat treatment at 773 K for 35 h （T4）. The solution-treated alloy presents low wear-resistance, because the hard β-phase is converted into thermally-stable, ductile and soft X-Mg12GdZn phase with LPSO structure in the alloy.

0.13 μm CMOS Stacked-FET两级功率放大器设计

基于TSMC 0.13μm CMOS工艺设计了一款适用于无线传感网络、工作频率为300~400 MHz的两级功率放大器。功率放大器驱动级采用共源共栅结构,输出级采用了3-stack FET结构,采用线性化技术改进传统偏置电路,提高了功率放大器线性度。电源电压为3.6 V,芯片面积为0.31 mm×0.35 mm。利用Cadence Spectre RF软件工具对所设计的功率放大器电路进行仿真,结果表明,工作频率为350 MHz时,功率放大器的饱和输出功率为24.2 d Bm,最大功率附加效率为52.5%,小信号增益达到38.15 d B。在300~400 MHz频带内功率放大器的饱和输出功率大于23.9 d Bm,1 d B压缩点输出功率大于22.9 d Bm,最大功率附加效率大于47%,小信号增益大于37 d B,增益平坦度小于±0.7 d B。

Microstructure and phase composition of as-cast Mg-9Er-6Y-xZn-0.6Zr alloys

The microstructure and phase composition of as-cast Mg-9Er-6Y-xZn-0.6Zr （x=1, 2, 3, 4; normal mass fraction in %） alloys were investigated. In low Zn content, aside from the major second phase of Mg24（Er, Y, Zn）5, there are a few lamellar phases that grow parallel with each other from the grain boundaries to the grain interior. With Zn content increasing, the Mg24（Er, Y, Zn）5 phase decreases, but the Mg12Zn（Y, Er） phase and lamellar phases continuously increase. When Zn content reaches 4% （normal mass fraction）, the Mg12Zn（Y, Er） phase mainly exists as large bulks, and some a-Mg grains are thoroughly penetrated by the lamellar phases. Moreover, the crystallography structures of the Mgl2Zn（Y, Er） and Mg24（Er, Y, Zn）5 phases are confirmed as 18R-type long-period stacking ordered structure and body-centred cubic structure, respectively.

Synthesis and Crystal Structure of a New Copper(II) Complex with 4-Cyanobenzoic Acid

A new Cu（Ⅱ） complex [Cu（4-cba）（1,10-phen）（H2O）2]（NO3） （4-Hcba = 4-cyanobenzoic acid） has been synthesized by solvothermal reaction in an ethanol/water mixed solution at 100 ℃ and structurally characterized by single-crystal X-ray diffraction. Crystallographic data： C20H16CuN4O7, Mr= 487.91, triclinic, space group PI, a = 7.8420（2）, b = 9.1070（2）, c = 15.1140（6） A, a = 76.889（9）, β = 81.332（11）, γ = 74.844（ 11）°, V = 1009.89（5） A^3, Z = 2, Dc = 1.605 g/cm^3, F（000） = 498, μ = 1.134 mm^-1, the final R = 0.0379 and wR = 0.0865 for 2977 observed reflections with 1 〉 2σ（Ⅰ）. The Cu（Ⅱ） atom is coordinated by two terminal water molecules, one chelating 1,10-phen molecule and one monodentate 4-cba ligand to form a slightly distorted square pyramid. The title complex molecules are connected through hydrogen bonds and π-π stacking interactions to generate a 2D layered network. The thermogravimetric analysis of the title complex has also been discussed.

Synthesis and Crystal Structure of 4-Salicylimine-3, 5-bis(2-hydroxyphenyl)-1, 2, 4-triazole JI Bao-Minga

The title compound, 4-salicylimine-3, 5-bis(2-hydroxyphenyl)-1, 2, 4-triazole, was obtained by the condensation reaction of 4-amino-3, 5-bis(2-hydroxyphenyl)-1, 2, 4-triazole with salicylaldehyde in methanol. The crystal structure (C21H16N4O3, Mr = 372.38) belongs to monoclinic system, space group P21/n with a = 10.507(2), b = 16.878(3), c = 11.199(2) ? = 110.86(3), V = 1855.9(6) ?, Z = 4, Dc = 1.333 g/cm3, F(000) = 776, (MoK? = 0.092 mm-1, R = 0.0552 and wR = 0.1095 for 1920 reflections ( I > 2.0(I) ). The analytical results of crystal structure show that there are two different non-covalent interactions in the compound. One is hydrogen bond, and the other p-p stacking interaction. These two types of non-covalent interactions play an important role in the packing of crystal.

Crystal Structure and Luminescence of a New Zn(Ⅱ) Complex [Zn(L)(IPP)(H_2O)]·2H_2O Based on Nicotinate Derivative and 1,10-Phenanthroline Derivative

A new Zn（II） complex, [Zn（L）（IPP）（H2O）]＇2H2O（1, H2L = 3-carboxy-l-car- boxymethyl-2-oxidopyridinium and IPP = 2-（1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl）phenol）, was synthesized under hydrothermal conditions and its structure was determined by single-crystal X-ray diffraction. It crystallizes in triclinic, space group Pi with a = 8.5023（17）, b = 9.945（2）, c = 15.573（3） A, a = 95.87（3）, β = 102.56（3）, y = 100.73（3）°, V= 1248.7（4） A3, Z= 2, C27H22N5O9Zn, Mr= 625.87, Dc = 1.665 g/cm^3, F（000） = 642, μ（MoKa） = 1.053 mm^-1, R = 0.0474 and wR = 0.1352. In 1, one L2-, one 1PP and one water molecule coordinate to the same Zn（II） atom to give a discrete complex with two lattice water molecules. Adjacent [Zn（L）（IPP）（H20）].2H20 molecules interact through π-π stacking between two IPP ligands to form a supramolecular chain. The N-H…O and O-H…N hydrogen bonds further stabilize the supramolecular chain structure of 1. The solid state luminescent property of 1 was also studied.