Influence of Waveguide Properties on Wave Prototypes Likely to Accompany the Dynamics of Four-Wave Mixing in Optical Fibers

In this article, we study the impacts of nonlinearity and dispersion on signals likely to propagate in the context of the dynamics of four-wave mixing. Thus, we use an indirect resolution technique based on the use of the iB-function to first decouple the nonlinear partial differential equations that govern the propagation dynamics in this case, and subsequently solve them to propose some prototype solutions. These analytical solutions have been obtained;we check the impact of nonlinearity and dispersion. The interest of this work lies not only in the resolution of the partial differential equations that govern the dynamics of wave propagation in this case since these equations not at all easy to integrate analytically and their analytical solutions are very rare, in other words, we propose analytically the solutions of the nonlinear coupled partial differential equations which govern the dynamics of four-wave mixing in optical fibers. Beyond the physical interest of this work, there is also an appreciable mathematical interest.

Impacts of solid physical properties on the performances of a slurry external airlift loop reactor integrating mixing and separation

Solid physical properties are vital for the design, optimization, and scale-up of gas–liquid–solid multiphase reactors. The complex and interactional effects of the solid physical properties, including particle diameter, density, wettability, and sphericity, on the hydrodynamic behaviors in a new external airlift loop reactor(EALR) integrating mixing and separation are decoupled in this work. Two semi-empirical equations are proposed and validated to predict the overall gas holdup and liquid circulating velocity satisfactorily, and then the individual influence of such solid physical properties is further investigated. The results demonstrate that both the overall gas holdup in the riser and the liquid circulating velocity in the downcomer increase with the contact angle, but decrease with particle size, density, and sphericity.Additionally, the impact of the particle size on the liquid circulating velocity is also profoundly revealed on a micro-level considering the particle size distribution. Moreover, the axial solid concentration distribution is discussed, and the uniformity of the slurry is described by the mixing index of the solid particles. The results show that a more homogeneous mixture can be achieved by adding finer particles other than attaining violent turbulence. Therefore, this work lays a foundation for the design, scale-up, and industrialization of the EALRs.

Electronic properties of 2D materials and their junctions

With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific community.Despite tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its infancy.Thus,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers mobility.The atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device operations.We also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various applications.Presently,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk semiconductors.We also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional junctions.Finally,we talked about the problems and potential for the future.

Investigating Stability Properties for Transition Metal Carbonate Precursors Using Universal Cluster Expansion Technique(UNCLE)as Cathodes for Li-Ion Batteries

The universal cluster expansion technique was used in this study to determine the binary phase diagrams for the transition metal carbonate precursors MCO3(M:Mn,Ni,Co).The use of mixed cathode materials in lithium-ion batteries such as NMC(Ni,Mn and Co)formulations,is a strategic approach to optimize performance,enhance safety and address cost and environmental considerations in the rapidly evolving field of energy storage.This study focuses on the cost issue related to lithium ion batteries by investigating the manganese rich NMC since manganese is more abundant and cost-effective.We doped MnCO3 with nickel and doped MnCO3 with cobalt then ran cluster expansion calculations to generate binary phases.The binary phase diagrams generated indicated that doping MnCO3 with nickel favours the Mn-rich side,while doping MnCO3 with cobalt favours 50%Mn-rich and 50%Co-rich.We further extracted the most stable structures from both binary diagrams and determined their electronic,mechanical and vibrational stabilities using DFT(density functional theory)calculations within the LDA(local gradient approximation)with Hubbard parameter(U).The electronic properties revealed that both materials are semiconductors due to their narrow energy band gap obtained while the mechanical properties showed that structures are mechanically stable since their necessary conditions for trigonal and triclinic systems were satisfied.

Model Analysis of Influences of Aerosol Mixing State upon Its Optical Properties in East Asia

The air quality model system RAMS （Regional Atmospheric Modeling System）-CMAQ （Models-3 Com- munity Multi-scale Air Quality） coupled with an aerosol optical/radiative module was applied to investigate the impact of different aerosol mixing states （i.e., externally mixed, half externally and half internally mixed, and internally mixed） oil radiative forcing in East Asia. The simulation results show that the aerosol optical depth （AOD） generally increased when the aerosol mixing state changed from externally mixed to internally mixed, while the single scattering albedo （SSA） decreased. Therefore, the scattering and absorption proper- ties of aerosols can be significantly affected by the change of aerosol mixing states. Comparison of simulated and observed SSAs at five AERONET （Aerosol Robotic Network） sites suggests that SSA could be better estimated by considering aerosol particles to be internally mixed. Model analysis indicates that the impact of aerosol mixing state upon aerosol direct radiative forcing （DRF） is complex. Generally, the cooling effect of aerosols over East Asia are enhanced in the northern part of East Asia （Northern China, Korean peninsula, and the surrounding area of Japan） and are reduced in the southern part of East. Asia （Sichuan Basin and Southeast China） by internal mixing process, and the variation range can reach ＋5 W m 2. The analysis shows that the internal mixing between inorganic salt and dust is likely the main reason that the cooling effect strengthens. Conversely, the internal nfixture of anthropogenic aerosols, including sulfate, nitrate, ammonium, black carbon, and organic carbon, could obviously weaken the cooling effect.

Study on Relationship Between the Size Distribution of Glutenin Polymeric Protein and Wheat Flour Mixing Properties

Parental varieties Suneca and Cook have contrasting alleles at each of the five glutenin subunit loci (Glu-B1, Glu-D1 Glu-A3, Glu-B3, and Glu-D3), a set of 60 lines homozygous at these loci from the F4 progeny population of Suneca X Cook was chosen to analyze the variation of the size distribution of glutenin polymeric protein (measured by SE-HPLC) and flour mixing properties of these lines and to study relationship between the size distribution of glutenin polymeric protein and wheat flour mixing properties. The results showed that there were very significant differences among the relative size distributions of glutenin polymeric protein (i.e. percentage of unextracTable polymeric protein in the total polymeric protein, or UPP%) and dough development times (i.e. peak time of mixograph, or PTM) of different homozygous lines, respectively. Flour mixograph shape was closely related to UPP% value. The results also indicated that UPP% was very strongly positive correlation with PTM and negative correlation with peak height of mixograph (PHM). Comparing with flour protein content (FP%), UPP% gave greater effect on PTM and PHM, i.e. flour mixing properties, and it can be considered as one of criteria for quality selecting from early generation of breeding program.

Relationship between Physico-Mechanical Properties, Compacting Pressure and Mixing Proportion of Briquettes Produced from Maize Cobs and Sawdust

This study examined the relationship between selected physico-mechanical properties, compacting pressure and mixing proportion of briquettes produced from combination of maize cob particles and sawdust of low, medium and high density timber species. Particle sizes of maize cobs and sawdust used for the study were ≤1 mm. The two materials were combined at mixing percentages of 90:10, 70:30 and 50:50 (Sawdust:maize cobs). Briquettes were produced at room temperature (28°C) using compacting pressures 20, 30, 40 and 50 MPa. The results suggested that combining maize cob particles with sawdust of low, medium and high density wood species could significantly enhance the relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from agricultural biomass residue like maize cobs. The results further indicated that the physical and mechanical characteristics of briquettes produced from combinations of sawdust of low density species and maize cobs were exceptionally higher than that produced from combinations of maize cob particles, and medium density and high density timber species. The R2 values for the regression model between the independent variables (mixing percentage and compacting pressure) and relaxed density, compressive strength in cleft and impact resistance index of briquettes produced from combinations of maize cob particles and sawdust of low density species (Ceiba pentandra) were 0.966, 0.932 and 0.710 respectively. This study provides a hope for briquetting maize cobs at room temperature using a low compacting pressure.

Comparative structural and electrochemical properties of mixed P2/O′3-layered sodium nickel manganese oxide prepared by sol-gel and electrospinning methods:Effect of Na-excess content

The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N_(2) adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g^(-1)at0.1 A·g^(-1)in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors.

Beam steering in planar photonic crystal based on its anomalous dispersive properties

We utilize the anomalous dispersion of planar photonic crystals near the dielectric band edge to control the wavelength-dependent propagation of light. We typically observe an angular swing of up to 10°as the input wavelength is changed from 1290 nm to 1310 rim, which signifies an angular dispersion of 0.5°/am （＂Superprism＂ phenomenon）. Such a strong angular dispersion is of the order required for WDM systems. By tuning the incident angle, light beams with up to 20° divergence were collimated over a 25 nm （1285 nm to 1310 nm） bandwidth using a triangular lattice （＂Supercollimator＂ phenomenon）. The wavelength collimating range can be extended from 25 nm to 40 nm by changing the lattice from triangular to square. These two devices can be realized in the same configuration, simply by tuning the wavelength. Sources of loss are discussed.

Sound absorbing properties of spiral metasurfaces inspired by micro-perforated plates

As a kind of classical low-frequency sound-absorbing material,the microperforated plate(MPP)has been widely used.Here,we inspired by the sound absorption mechanism of the MPP,a spiral metasurface(SM)is designed and the analytical solution of acoustic impedance and sound absorption coefficient are obtained.The relationship between the sound absorption properties of the MPP and the SM with their own structures is systematically studied,and the analytical solutions are used to optimise the structure.It is concluded that the MPP and the SM of the same thickness achieve effective absorption in the frequency range between 390-900 Hz and 1920-4266 Hz,with a total thickness less than 1/6 of the wavelength.Meanwhile,the numerical calculation shows that the MPP and SM can match well with the background medium in the effective rang.Our study provides new insights into the design methods of sound-absorbing materials and is potentially suitable for many acoustic engineering applications.

Influences of oxide content and sintering temperature on microstructures and mechanical properties of intragranular-oxide strengthened iron alloys prepared by spark plasma sintering

How to increase strength without sacrificing ductility has been developed as a key goal in the manufacture of high-performance metals or alloys. Herein, the double-nanophase intragranular yttrium oxide dispersion strengthened iron alloy with high strength and appreciable ductility was fabricated by solution combustion route and subsequent spark plasma sintering, and the influences of yttrium oxide content and sintering temperature on microstructures and mechanical properties were investigated. The results show at the same sintering temperature,with the increase of yttrium oxide content, the relative density of the sintered alloy decreases and the strength increases. For Fe–2wt%Y_(2)O_(3)alloy, as the sintering temperature increases gradually, the compressive strength decreases, while the strain-to-failure increases. The Fe–2wt%Y_(2)O_(3)alloy with 15.5 nm Y_(2)O_(3)particles uniformly distributed into the 147.5 nm iron grain interior sintered at 650℃ presents a high ultimate compressive strength of 1.86 GPa and large strain-to-failure of 29%. The grain boundary strengthening and intragranular second-phase particle dispersion strengthening are the main dominant mechanisms to enhance the mechanical properties of the alloy.

Optical and electrical properties of BaSnO_(3) and In_2O_(3) mixed transparent conductive films deposited by filtered cathodic vacuum arc technique at room temperature

For the crystalline temperature of BaSnO_(3)(BTO)was above 650℃,the transparent conductive BTO-based films were always deposited above this temperature on epitaxy substrates by pulsed laser deposition or molecular beam epitaxy till now which limited there application in low temperature device process.In the article,the microstructure,optical and electrical of BTO and In_(2)O_(3) mixed transparent conductive BaInSnO_(x)(BITO)film deposited by filtered cathodic vacuum arc technique(FCVA)on glass substrate at room temperature were firstly reported.The BITO film with thickness of 300 nm had mainly In_(2)O_(3) polycrystalline phase,and minor polycrystalline BTO phase with(001),(011),(111),(002),(222)crystal faces which were first deposited at room temperature on amorphous glass.The transmittance was 70%–80%in the visible light region with linear refractive index of 1.94 and extinction coefficient of 0.004 at 550-nm wavelength.The basic optical properties included the real and imaginary parts,high frequency dielectric constants,the absorption coefficient,the Urbach energy,the indirect and direct band gaps,the oscillator and dispersion energies,the static refractive index and dielectric constant,the average oscillator wavelength,oscillator length strength,the linear and the third-order nonlinear optical susceptibilities,and the nonlinear refractive index were all calculated.The film was the n-type conductor with sheet resistance of 704.7Ω/□,resistivity of 0.02Ω⋅cm,mobility of 18.9 cm2/V⋅s,and carrier electron concentration of 1.6×10^(19) cm^(−3) at room temperature.The results suggested that the BITO film deposited by FCVA had potential application in transparent conductive films-based low temperature device process.

Petrophysical properties and their influencing factors of carbonates in the fourth member of Sinian Dengying Formation, Sichuan Basin, SW China

Based on the measurements of petrological, petrophysical and elastic properties of the samples of different sedimentary facies in the fourth member of Sinian Dengying Formation (Deng 4 Member) in the Sichuan Basin, the diagenetic processes of reservoirs of different sedimentary facies and their controls on the petrophysical properties were discussed. The results show that cracks and mineral composition jointly control the petrophysical properties, and both are significantly influenced by sedimentary environment and diagenesis. The microbial dolomite of mound-shoal facies mainly experienced multi-stage dolomitization, penecontemporaneous dissolution, tectonic rupture and hydrothermal/organic acid dissolution processes, giving rise to cracks and dissolved pores. The grannular dolomite of inter-mound-shoal bottomland or dolomitic lagoon facies mainly underwent mechanical compaction, burial dolomitization and tectonic-hydrothermal action, creating cracks and intercrystalline pores. The diagenesis related to crack development increases the pressure- and saturation-dependent effects of samples, leading to significant decrease in the compressional wave impedance and Poisson's ratio. Dolomitization changes the properties of mineral particles, resulting in a Poisson's ratio close to dolomite. The muddy, siliceous and calcareous sediments in the low-energy environment lead to the decrease of impedance and the differential change of Poisson's ratio (significantly increased or decreased). The samples with both cracks and dissolved pores show high P-wave velocity dispersion characteristics, and the P-wave velocity dispersion of samples with only fractures or pores is the lowest.

稠油开采中多元热复合流体相态的研究进展

稠油的储量远超常规石油的储量,但因稠油黏度大和密度大的特点而难以开采,高效经济开发稠油已成为石油领域的研究重点。热复合开采技术是目前高效开发稠油油藏的关键技术,其中多元热复合流体的相态特征是稠油油藏开采流程设计与评价的关键。为此,从热复合开采技术中的混合气体系和稠油-气体系2个方面,系统地阐述了多元热复合流体相态的实验和理论研究现状。对于混合气体系相态,多采用静态法进行实验测试,使用状态方程结合混合规则进行理论预测,CO_(2),N_(2),H_(2)O和CH_(4)等常见气体分子组成的二元体系的相态测试趋于成熟,但缺少多元体系的测试数据与预测模型;对于稠油-气体系相态,总结了一般性实验流程与近年实验结果,提出一种加速油气相平衡的新型实验装置构想,指出目前理论预测在气体种类、注气量、气体扩散模型、二元相互作用系数等方面的不足。进而对多元热复合流体相态研究提出展望,以期促进热复合开采技术进一步的机理研究与参数优化。

现代产业学院混合所有制办学的现实意义、机制架构与路径选择

现代产业学院混合所有制办学有助于优化产业资源市场化配置、推动人才培养理实一体化、促进产业经济高质量发展和强化校企合作共同体构建。基本机制包括组织管理的健全机制、优质教学资源的共建机制、教师教学创新团队的共管机制、教育教学模式的改进机制和发展成果的共享机制。应探索混合制管理体制、协同建设系列优质教学资源、协同管理高素质教师教学创新团队、协同改进教育教学模式和共同分享发展成果,规范与促进现代产业学院混合所有制办学。

连续重整装置混合二甲苯产量最大化策略分析与实践

介绍了某公司1.2 Mt/a连续重整装置的实际生产情况,探讨了影响混合二甲苯产品产量的原因,并提出对应优化措施。以混合二甲苯产量为优化目标时,分别在原料优化、反应过程和产品精馏3个环节探讨相关优化策略。优化措施:原料优化方面,按石脑油资源芳烃潜含量排序,将重整进料芳烃潜含量控制在45%左右;根据装置负荷能力和原料情况,重整进料初馏点从67℃提至74℃,反应进料中C_(8)组分油的质量分数提高了1.8百分点,混合二甲苯产量提高约2 t/h;反应过程方面,反应温度从524℃降至518℃,提高了芳烃的转化率;氯质量分数控制在0.5~0.7μg/g,确保催化剂酸性功能;产品精馏方面,以目标产品质量为目标,优化精馏部分灵敏板温度,优化混合二甲苯分离策略,避免二甲苯资源流入汽油,将C^(+)_(9)石脑油中对二甲苯含量控制至最低。调整结果:避免了混合二甲苯产品含量异常降低,同时混合二甲苯实现产量最大化。

高光泽喷墨打印纸的涂层结构及其性能比较研究

以三种市售喷墨打印纸为研究对象,分别以样品A、样品B、样品C表示,其中样品A和样品C为国内产品阿博特和佳艺,样品B为国外产品古楼.研究确定了三种样品涂层的结构组成,并分析三种样品涂层的表面性能,这有助于了解市场上喷墨打印纸的产品性能现状,对影响喷墨打印纸涂层性能的各因素的研究具有指导意义.采用AFM和SEM观察三种样品涂层表面形貌,发现样品A和样品B的涂层颜料颗粒分散均匀性良好,样品C涂层颜料颗粒聚集,分散均匀性较差;截面SEM和EDS分析结果表明:只有样品B涂层具有双层结构,其中,底层为铝基颜料和硅基颜料,面层只有铝基颜料,样品A和样品C的涂层均为单层铝基材料.对三种样品涂层表面的性能进行分析,结果表明:三种样品的基础性能都符合产品质量标准,其中,样品B的涂层具有最高的光泽度(74.30%),硬度(3H)和耐水性,在吸墨性上样品B涂层的吸墨性(64.7%)高于样品C(57.9%),略低于样品A(69.2%),样品B在三种样品中综合性能最优异.最后,提出一种提高喷墨打印纸性能的双层涂布工艺方案,这为提高喷墨打印纸性能提供了方向,对高级喷墨打印纸的研究具有实际意义.

锗溴混合掺杂调控钙钛矿太阳电池光电特性的第一性原理研究

采用第一性原理方法对锗溴混合掺杂下甲胺基钙钛矿(MAPbI3)材料的能带结构、态密度、介电函数和吸收光谱进行研究。构建MAPbI_(3)、MAPb_(0.75)Ge_(0.25)I_(3)、MAPbI_(2.5)Br_(0.5)、MAPb_(0.75)Ge_(0.25)I_(2.5)Br_(0.5)这4种钙钛矿结构模型并优化其结构,得出光电特性。研究结果表明,锗溴混合掺杂可改变价带顶与导带底位置及斜率,调控带隙值大小,同时混合掺杂也会改变价带顶与导带底的斜率,4种钙钛矿模型中锗溴混合掺杂时价带顶与导带底的斜率最小,有利于电子跃迁,提升光电转换效率;掺杂锗可提高钙钛矿在可见光区的吸收性能,掺杂溴对钙钛矿光学特性影响不大。

时效处理对Cu-Y_(2)O_(3)-Ti复合材料组织及性能的影响

以Cu、Y、Ti和CuO粉末为原料,采用机械合金化(MA)和热还原的方法制备了Cu-Y_(2)O_(3)-Ti复合粉末。然后经放电等离子烧结(SPS)技术制备了Cu-Y_(2)O_(3)-Ti复合材料,并对材料进行了900℃固溶1 h和不同温度时效2 h的处理。采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)、拉伸试验和导电率测量仪等研究了不同温度时效处理对Cu-Y_(2)O_(3)-Ti复合材料组织及性能的影响。结果表明:随着时效温度的升高,Cu-Y_(2)O_(3)-Ti复合材料的晶粒和第二相尺寸增大,导电率降低,最大应变和抗拉强度先增大后减小。Cu-Y_(2)O_(3)-Ti复合材料经900℃固溶1 h+400℃时效2 h后,综合性能最优,其具有良好塑性的同时,抗拉强度和导电率分别达到326.4 MPa和73.0%IACS。

SMC再生SBS沥青的流变性能和微观特性研究

【目的】探究新型温拌再生剂甲基苯乙烯共聚物(styreneic methyl copolymer,SMC)对老化苯乙烯系热塑性弹性体(styrene butadiene styrene,SBS)改性沥青的再生效果和再生机理。【方法】首先,在室内制备不同老化程度的沥青。然后,采用SMC再生剂对不同老化程度的SBS改性沥青进行再生。接着,对再生后的SBS改性沥青进行动态剪切流变和低温弯曲蠕变试验,以评价其流变性能。最后,开展红外光谱试验以揭示其作用机理,进行电镜扫描试验以验证SMC再生剂的再生效果。【结果】SMC再生剂会降低老化SBS改性沥青的车辙因子,降低老化SBS改性沥青的恢复率,同时会使老化SBS改性沥青的低温性能得到极大提升。SMC再生剂未与SBS改性沥青发生化学反应,两者仅为物理共混。同时,SMC再生剂能够弥补沥青因老化产生的裂缝。【结论】SMC再生剂对老化SBS改性沥青具有较好的修复效果,能够为沥青的再生提供一种新的途径。