Al-incorporation into Li7La3Zr2O12 solid electrolyte keeping stabilized cubic phase for all-solid-state Li batteries

We observe the influence of AI occupancies in Li sites on the formation process of the garnet solid elec- trolyte of Li_7La_3Zr_2O_12 （LLZO）. A direct incorporation of AI is first promoted in a Li-insufficient garnet solid electrolyte during the calcination process of 850 ℃ and then the cubic phase of LLZO is obtained after successive annealing step of 1000 ℃. Comparing to pristine LLZO, AI incorporated LLZO shows less formation of Li_2CO_3, keeping crystallographic and physicochemical properties. This AI incorporation im- proves both the ionic conductivity and interfacial resistance to poisoning procedure.

An apodized cubic phase mask used in a wavefront coding system to extend the depth of field

The point spread function(PSF)caused by a wavefront coding system with a cubic phase mask has big side-lobes which leads to bad image restoration.This paper proposes a novel apodized cubic phase mask to suppress the side-lobes of the PSF.Simulated annealing algorithm is used to optimize the cubic and the truncation parameter of the phase mask.The system with the novel phase mask has better performance in the modulation transfer function(MTF)especially in low-and-medium spatial frequency region.The simulation results show that the restored images with the novel phase mask are superior to the one with the classic cubic phase mask in contrast and ringing effect.The experimental results show that the side-lobes of the PSF are suppressed by using the apodized cubic phase mask.

Phase composition,conductivity,and sensor properties of cerium-doped indium oxide

The hydrothermal synthesis of In_(2)O_(3)and CeO_(2)–In_(2)O_(3)is investigated as well as the properties of sensor layers based on these compounds.During the synthesis of In_(2)O_(3),intermediate products In(OH)_(3)and InOOH are formed,which are the precursors of stable cubic(c-In_(2)O_(3))and metastable rhombohedral(rh-In_(2)O_(3))phases,respectively.A transition from c-In_(2)O_(3)to rh-In_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-In_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-In_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-In_(2)O_(3).The reverse situation is observed in composites based on c-In_(2)O_(3).Compared to In_(2)O_(3)and CeO_(2)–In_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between In_(2)O_(3)and CeO_(2).

Quantum efficiency of luminescence in high-pressure cubic phase SrB_2O_(4-y)X_y: Eu^(2+) (X=F, Cl)

In the present note, through partial substituting of O2- by F-, CL- halogen ions, the HPCP （high-pressure cubic phase） of SrB2O4-yXy: Eu2+ （X=F, Cl） has been synthesized at 800℃ and 3.05GPa for the first time. The results show that the QE （luminescence quantum efficience） of HPCP doped by Cl is twice that of HPCP without doping, and 200

Model of Cubic Cell for Description of Some Phase Transitions in Crystals

The purpose of the research is to develop a dynamical theory of phase transitions in crystalline structures, when except for temperature, the pressure is acting. So, the phase diagram temperature-pressure (dimensions) must be constructed. In general case, it is a complicated question, which can be solved for simple models of crystal, as three atomic models, introduced in the work of Frenkel [1]. In this model, three identical atoms are placed on the straight line and interact with the forces, which can be described by the expression, given in the article of Lennard-Jones [2]. Such simple model may have success, when the crystalline structure is simple, which consists of one type of atoms, for example: carbon. The model was generalized to cubic cell model with a moving atom in the inner part of the cell. The rigorous calculation of phase diagram for transition graphite-diamond shows some similarity with results of numerous experimental investigations (which are not discussed here). So, the way of phase diagram calculation may attract attention.

放电等离子体烧结BaTiO_(3-x)Bi(Ni_(0.5)Zr_(0.5))O_(3)陶瓷的介电和阻抗性能

采用传统固相反应法合成BaTiO_(3-x)Bi(Ni_(0.5)Zr_(0.5))O_(3)粉体和放电等离子体烧结技术制备BaTiO_(3-x)Bi(Ni_(0.5)Zr_(0.5))O_(3)陶瓷,研究陶瓷的晶体结构、微观形貌、介电和阻抗性能。结果表明:BaTiO_(3)-0.10Bi(Ni_(0.5)Zr_(0.5))O_(3)陶瓷具有钙钛矿型,晶体结构为赝立方相,晶粒尺寸约为0.64μm,密度为5.81 g/cm^(3),最大介电常数为7149,且随频率升高相变温度向高温移动。在1 kHz下,BaTiO_(3)-0.10Bi(Ni_(0.5)Zr_(0.5))O_(3)陶瓷的ln(1/ε-1/ε_(m))与ln(T-T_(m))的拟合曲线斜率为1.61,在-41~169℃内,Δε/ε_(25℃)≤±15%,表明样品有良好的温度稳定性。此外,随温度和频率的升高,材料的阻抗降低,在50℃下,当频率为100 Hz时,电阻为2.33×10~6Ω,离子电导率为10^(-8)S/cm。

波前编码红外成像系统的温度梯度适应能力探究

利用波前编码技术为红外光学系统进行无热化设计可提高其在不同均匀工作温度下的适应能力,但针对温度突变、成像系统内温度分布不均情况,波前编码技术是否能正常进行成像及其适用的温度范围还有待进一步研究.为简化分析流程,采用温度梯度模型来仿真非稳态下的温度变化.利用温度梯度模型来定性分析光学系统在轴向、径向温度梯度为系统引入的附加像差.计算两个方向下的光程差变化来比较两种温度梯度环境下系统的成像性能差异.在此基础上,为非稳态温度环境下红外光学系统的设计建立了结合光/机/热分析的无热化设计流程,通过ZEMAX设计了一套最大轴向尺寸为85 mm、最大径向尺寸为25 mm的红外光学系统,通过SolidWorks加载轴向和径向的热形变,探究所设计的系统能够适用的温度梯度范围.结果表明,结合光/机/热分析的无热化设计流程可以有效表明系统在非稳态温度下的成像情况.对上述采用三次相位板进行无热化设计的红外光学系统,在非稳态温度下可以适应±10℃的轴向温差范围,但是仅可以适应±1℃的径向温差范围.因此在进行红外波前编码光学系统的无热化设计时,需要对径向方向进行重点优化.

晶相设计钌基纳米催化剂提高CO_(2)甲烷化活性

金属纳米颗粒在许多化学反应中表现出优异的催化性能,因而广泛用于能源和环境等催化领域.形貌是影响其催化行为的关键因素之一,它通过改变金属纳米颗粒表层原子排列结构,进而调控化学反应过程中的物质吸附、催化机理和反应动力学.此外,由于金属存在多种晶相结构,其纳米颗粒暴露的表面结构也可通过改变晶相得以实现.该调控策略可使得纳米颗粒具有独特的表面结构,并展现出不同的催化性能.因此,金属纳米颗粒的晶相设计为优化金属催化剂的催化性能提供了一种有效方式.Ru基纳米催化剂对CO_(2)甲烷化反应具有较好的活性和选择性,且密堆积的Ru(0001)晶面被证明是hcp相Ru纳米催化剂的活性中心,而(10-11)面对CO_(2)甲烷化反应的贡献较小.因此,开发具有更丰富密堆积fcc-(111)表面的Ru基纳米催化剂,有望大幅提高CO_(2)甲烷化的活性.本文首先通过密度泛函理论计算和微观动力学模拟,研究了fcc相Ru纳米催化剂的密堆积(111)晶面上CO_(2)加氢反应的催化机理.结果表明,与hcp-(0001)相比,该密堆积的fcc-(111)表面因能促进CO_(2)的吸附活化,而具有更好的CO_(2)甲烷化反应活性.制备了具有完全暴露fcc-(111)晶面的二十面体Ru金属纳米颗粒,并将其负载于惰性载体氧化铝上,结果表明,CO_(2)甲烷化活性比传统六方密堆积相(hcp)的钌基催化剂高5‒8倍,证实了fcc相催化剂具有更高的甲烷化催化性能.同时,在较高的反应温度下,fcc-晶相的Ru基催化剂在初始反应阶段甲烷化反应活性逐渐下降,但其CO_(2)甲烷化活性仍远高于hcp-相催化剂.原位X射线衍射和环境透射电镜等结果表明,在反应温度高于250°C条件下,fcc-晶相的金属催化剂发生部分晶相转变.该相变主要发生于Ru金属纳米颗粒的聚集体,并伴随着金属粒子的团聚和粒径的增长;然而,单颗粒分散的Ru纳米粒子在相同条件下仍能维持其fcc-晶相,从而确保了其较高的甲烷化活性.此外,原位红外结果进一步证实了CO_(2)甲烷化在Ru基纳米催化剂上通过氢化生成HCOO*中间体的反应路径,以及Ru纳米颗粒在反应过程中的动态结构演化.综上,金属纳米颗粒的晶相设计是调控表面原子结构及其催化反应性能的有效手段.通过对Ru基纳米催化剂的晶相设计,可以显著提升其在CO_(2)甲烷化反应中的催化活性.然而,潜在的高温晶相转变可导致催化剂活性的部分失活.总之,晶相设计通过对金属纳米粒子表面原子结构的调变,为高效催化剂的设计开发和反应机理的深入研究提供了新的机遇.

基于三次样条插值的M-QAM载波相位估计

在基于高阶调制的相干光通信传输系统中,接收端信号受相位噪声干扰会对系统性能产生直接的影响。传统的盲相位搜索(BPS)算法具有较高的线宽容差,适用于多种调制格式,但随着调制阶数的增加,用于BPS的测试相位数量会急剧加大。针对M元正交振幅调制(M-QAM)格式,本研究提出了一种新的低复杂度载波相位估计(CPE)算法。首先利用BPS算法,得到B个测试相位和平均欧氏距离之间的关系;然后在此基础上,提出了一种基于三次样条插值(CSI)的两级BPS载波相位估计算法,得到(2B−1)个等间隔插值相位和平均欧氏距离之间的光滑曲线关系;最后取曲线的最小值处所对应的相位值为最优相位估计值。仿真结果表明,在使用少量测试相位的前提下,通过CSI算法可以有效地对载波相位进行恢复,与BPS算法相比,CSI算法乘、加法器计算复杂度分别降低了38%和42%(16-QAM),为载波相位恢复提供了新思路。

极低温环境下立方相和四方相Nb_(3)Sn超导晶体力学及力-电耦合行为分析

Nb_(3)Sn超导相转变中的力电耦合效应给超导磁体装备的电磁性能指标和安全运行带来不利影响。鉴于Nb_(3)Sn具有立方相和四方相两种相结构,建立了Nb_(3)Sn立方相、四方相和混合相晶体力学模型,以及考虑变形-临界温度退化和变形-正常态电阻率变化的力电耦合响应模型。研究结果表明,相结构会导致单晶体弹性力学性能有所区别,但静水压作用下不同相结构的Nb_(3)Sn多晶体,其局部应力状态与相结构无关,仅取决于晶粒形貌和取向。由于不同的相结构在外载下的费米面上电子态密度的演变规律基本一致,使得变形诱导的临界温度退化行为对相结构没有依赖性。对于混合相Nb_(3)Sn正常态电阻率变化而言,温度低于马氏体相变温度时,可以采用基于电子-电子散射假设得到的T_(2)规律来描述;当温度高于马氏体相变温度时,由于四方相向立方相的转变,需要考虑电-声子耦合作用对正常态电阻率的贡献,可以采用拓展的Woodard-Cody电阻率模型来描述宏观电阻率的应变效应。研究结果提高了对不同相的临界性能退化机理的认识。

栀子苷立方液晶凝胶的制备、表征及体外评价

目的为促进水溶性栀子苷的透皮性能而制备栀子苷立方液晶凝胶(geniposide cubic liquid crystal gel,GE-CLC-G),并对其进行表征及体外评价。方法以甘油单油酸酯(glyceryl monooleate,GMO)为基质材料,采用注入法制备GE-CLC-G,通过三元相图筛选出空白立方液晶区域;采用单因素法优选GE-CLC-G的处方及工艺条件;建立栀子苷的HPLC含量测定方法;采用偏光显微镜(polarizing microscope,PLM)、小角X衍射仪(small angle X diffraction,SAXS)对产品进行表征;采用改良Franz扩散池,比较GE-CLC-G与栀子苷软膏的体外透皮特性;采用DHR-2流变仪,对比GE-CLC-G和栀子苷软膏的流变学性质。结果优选的GECLC-G处方及工艺为GMO∶无水乙醇∶水=64∶3∶33,1%栀子苷投药量,1%促渗剂(氮酮:丙二醇=1∶1),60℃涡旋3 min,25℃恒温箱密封、避光3 d。制得的GE-CLC-G为无色、澄明的凝胶状半固体;为立方相,其内部结构为双菱形(Pn3m)晶格;测得产品中栀子苷的含量为(9.94±0.02)mg/g,载药量较大,符合立方液晶的特点。含1%促渗剂的GE-CLC-G 24 h累积透皮率Q(%)和透皮速率常数Js明显高于不加促渗剂的栀子苷软膏和不加促渗剂的GE-CLC-G。流变学研究表明,GE-CLC-G属于非牛顿流体,生物黏附性好,结构更稳定。结论GE-CLC-G制备工艺简单,产品外观良好,PLM和SAXS可用于表征立方液晶凝胶,含量测定方法操作简单,专属性好;GE-CLC-G的体外透皮性能和流变学性质均明显优于栀子苷软膏。

Effect of the glyceryl monooleate-based lyotropic phases on skin permeation using in vitro diffusion and skin imaging

Glyceryl monooleate(GMO)is a polar lipid that can exist in various liquid crystalline phases in the presence of different amounts of water.It is regarded as a permeation enhancer due to its amphiphilic property.Various phases of GMO/solvent system containing sodium fluorescein were prepared to compare permeability using confocal laser scanning microscopy(CLSM).GMO was melted in a vial in a water bath heated to 45℃.Propylene glycol and hexanediol were homogeneously dissolved in the melted GMO.Sodium fluorescein in aqueous solution was diluted to various ratios and thoroughly mixed by an ultrasonic homogenizer.Each GMO/Solvent system with fluorescein was applied onto the epidermal side of excised pig skin and incubated overnight.CLSM was performed to observe how the GMO/solvent system in its different phases affect skin permeability.Cubic and lamellar phase formulations enhanced the fluorescein permeation through the stratum corneum.A solution system had the weakest permeability compared to the other two phases.Due to the amphiphilic nature of GMO,cubic and lamellar phases might reduce the barrier function of stratum corneum which was observed by CLSM as fluorescein accumulated in the dermis.Based on the results,the glyceryl monooleate lyotropic mixtures could be applied to enhance skin permeation in various topical and transdermal formulations.

WC-Co梯度硬质合金的研究现状

梯度硬质合金(Gradient Cemented Carbides)基于其特殊的结构或成分梯度变化,在不同的位置具备不同的性能,使整体具有优异的综合力学性能。介绍了粘结相梯度硬质合金、表面贫立方相梯度硬质合金、表面富立方相硬质合金和多层梯度结构硬质合金等基本制备原理、组织结构特点和性能优势,指出了梯度硬质合金的发展趋势。

机加工用硬质合金刀具材料粘结相的相变

由于机加工用硬质合金刀具材料中粘结相存在面心立方和密排六方这两种不同的相结构,而不同的相结构其力学性能差异较大,因此,为优化刀具综合力学性能和服役寿命,通过制备不同钴含量的梯度硬质合金,对制备后的梯度硬质合金不同钴含量的位置进行残余应力测量和粘结相EBSD检测方法分析粘结相相变的条件。研究结果表明:在高残余应力的区域,粘结相主要以面心立方的形式存在;而在低应力的区域,粘结相主要以密排六方的形式存在。

A Critical Study of the Elastic Properties and Stability of Heusler Compounds: Phase Change and Tetragonal <i>X₂YZ</i>Compounds

In the present work, the elastic constants and derived properties of tetragonal Heusler compounds were calculated using the high accuracy of the full-potential linearized augmented plane wave (FPLAPW) method. To find the criteria required for an accurate calculation, the consequences of increasing the numbers of k-points and plane waves on the convergence of the calculated elastic constants were explored. Once accurate elastic constants were calculated, elastic anisotropies, sound velocities, Debye temperatures, malleability, and other measurable physical properties were determined for the studied systems. The elastic properties suggested metallic bonding with intermediate malleability, between brittle and ductile, for the studied Heusler compounds. To address the effect of off-stoichiometry on the mechanical properties, the virtual crystal approximation (VCA) was used to calculate the elastic constants. The results indicated that an extreme correlation exists between the anisotropy ratio and the stoichiometry of the Heusler compounds, especially in the case of Ni2MnGa. Metastable cubic Ni2MnGa exhibits a very high anisotropy (≈28) and hypothetical cubic Rh2FeSn violates the Born-Huang stability criteria in the L21 structure. The bulk moduli of the investigated tetragonal compounds do not vary much (&asymp;130 ...190 GPa). The averaged values of the other elastic moduli are also rather similar, however, rather large differences are found for the elastic anisotropies of the compounds. These are reflected in very different spatial distributions of Young’s moduli when comparing the different compounds. The slowness surfaces of the compounds also differ considerably even though the average sound velocities are in the same order of magnitude (3.2 ... 3.6 km/s). The results demonstrate the importance of the elastic properties not only for purely tetragonal Heusler compounds but also for phase change materials that exhibit magnetic shape memory or magnetocaloric effects.

Cubic anvil cell apparatus for high-pressure and low-temperature physical property measurements

We will build a cubic anvil cell （CAC） apparatus for high-pressure and low-temperature physical property measurements in the synergic extreme condition user facility （SECUF）. In this article, we first introduce the operating principle, the development history, and the current status of the CAC apparatus, and subsequently describe the design plan and technical targets for the CAC in SECUF. We will demonstrate the unique advantages of CAC, i.e., excellent pressure homogeneity and large hydrostatic pressure capacity, by summarizing our recent research progresses using CAC. Finally, we conclude by providing some perspectives on the applications of CAC in the related research fields.

面心立方结构钛的研究进展

面心立方结构钛是一种亚稳相,最早发现于超薄钛膜。除此之外,钛及钛合金在经历大塑性变形之后,也常常会发生hcp→fcc钛及钛合金的相变。近年来,大量研究报道了钛及钛合金经冷轧、压缩、拉伸和球磨等加工后观察到面心立方结构钛。为此,对近几十年来面心立方结构钛的制备方法、相变机理及其变形行为的研究进展进行了详细介绍。现有研究已证实,面心立方结构钛不仅能够协调材料的变形,而且有利于材料强度的提高。

Universal critical properties of the Eulerian bond-cubic model

We investigate the Eulerian bond-cubic model on the square lattice by means of Monte Carlo simulations, using an efficient cluster algorithm and a finite-size scaling analysis. The critical points and four critical exponents of the model are determined for several values of n. Two of the exponents are fractal dimensions, which are obtained numerically for the first time. Our results are consistent with the Coulomb gas predictions for the critical O（n） branch for n 〈 2 and the results obtained by previous transfer matrix calculations. For n = 2, we find that the thermal exponent, the magnetic exponent and the fractal dimension of the largest critical Eulerian bond component are different from those of the critical 0（2） loop model. These results confirm that the cubic anisotropy is marginal at n = 2 but irrelevant for n〈2.

A four parameter cubic equation of state with temperature dependent covolume parameter

A four-parameter, Ghoderao–Dalvi–Narayan 2 cubic equation of state(GDN2 CEOS), is presented which incorporates the following: 1. The experimental value of the critical compressibility factor has been used as a fixed input parameter for calculations;2. All the parameters(a, b, c, d) of CEOS are temperature dependent functions in the subcritical region and are temperature independent functions in the supercritical region and;3. A new α function is introduced with two compound specific parameters which are estimated by matching saturated vapor pressure at two fixed temperature points Tr= 0.5, 0.7. Our formalism enables us to cast three of the four parameters of the CEOS as a function of the remaining parameter. The proposed CEOS is used to predict properties of 334 pure compounds, including saturated vapor pressure and liquid density, compressed liquid density, heat capacities at the constant pressure and volume, enthalpy of vaporization, sound velocity. To calculate thermodynamic properties of a pure compound, the present CEOS require the critical temperature, the critical pressure, the Pitzer’s acentric factor, the critical compressibility factor, and two parameters of the alpha function. The saturated liquid density predictions for pure fluids are very accurate when compared with GDN1(Ghoderao–Dalvi–Narayan 1),MPR(Modified Peng–Robinson), and PT(Patel–Teja) equations of state. Unlike MPR EOS, the proposed temperature dependent covolume parameter b in the present work satisfies all the constraints mentioned in the literature to avoid thermodynamic inconsistencies at the extreme temperature and pressure. Using van der Waals one-fluid mixing rule, the present CEOS is further used to predict bubble pressure and the vapor mole fraction of binary mixtures.

烧结气氛对表面无立方相硬质合金组织和性能的影响

分别在氩气和氮气烧结气氛下制备了表面无立方相硬质合金,借助电子背散射衍射(EBSD)分析了表面无立方相层(Cubic-phaseFreeLayer,CFL)及相邻含立方相侧的组织特征,并对比了两种合金的切削性能。结果表明:在氮气气氛中烧结时,合金的液相维持时间更长,WC晶粒较氩气气氛烧结更为粗大。同时,氮气气氛下立方相的溶解析出被抑制,形成的CFL厚度较薄,立方相晶粒的聚集程度低于氩气气氛烧结,分布更加均匀。氮气气氛烧结的合金刀片在切削过程中可长时间维持刀尖形状,不发生软化变形,切削性能优于氩气气氛烧结的刀片。