Composite beam–columns with interlayer slip—Approximate analysis

An approximate second order analysis procedure for composite beam–columns with interlayer slip subjected to transverse loading and axial compressive loads is developed. The magnification factors to be applied to the first order solutions in order to estimate the deflections and internal forces obtained by the second order analysis approach are presented. The method of applying magnification factors to internal axial forces is discussed. The approximate second order analysis procedure is developed for the four Euler cases with various transverse load conditions. The procedure is applied to and the accuracy is illustrated for simply supported partially beam–columns of steel and concrete, and timber and concrete with different bending stiffness and interlayer slip properties. The deflections and internal forces obtained by the approximate method compared extremely well, except for slip forces in case of very flexible shear connectors, with those obtained by the more rigorous second order analysis approach for different composite action (partial interaction) parameters (shear connector stiffness values). The study also shows that the magnification factor associated with the deflections can be utilized to estimate also the internal actions, except shear forces in case of very flexible shear connectors, in the second order case with minimal error for simply supported beam–columns. Thus, for members with shear connector stiffness of structural significance the proposed approximate method can be used in general for simply supported beam–columns. For other boundary and loading conditions, the approximate method needs to be re-evaluated. The approach of using one magnification factor greatly simplifies the analysis task for those components.     

Control of nano-sized interlayer space of lamellar vanadyl benzylphosphate

Nano-sized interlayer space of lamellar vanadyl benzylphosphate was controlled by water content in starting solution. Depending on the water content, three types of lamellar vanadyl benzylphosphate having basal spacings of 1.4 nm, 1.9 nm and 2.3 nm were obtained. It was suggested that the difference in the concentrations of benzyl and hydroxyl groups in the interlayer leads to the variation of the interlayer space.     

Controlled anisotropy in 3D printing of silica-based ceramic cores through oxidization reaction of aluminum powders

Ceramic cores are key components to form inner hollow structures in aero-engine blades, and 3D printing is an ideal molding technology for ceramic cores. In this work, silica-based ceramic cores are fabricate via 3D printing of digital light processing (DLP) stereolithography, and the anisotropy in microstructure and property are controlled by aluminum powders. The ceramic cores without aluminum powders exhibit anisotropic microstructure with interlayer gaps, which get narrower and disappear with doping of 7.5–10 wt% of aluminum powders, due to the volume expansion during oxidization reaction of aluminum powders filling the interlayer gaps. The anisotropy in mechanical property is rely on the printing direction, and the ratio of strength in different directions (σ_V/σ_H) is put forward to value the mechanical anisotropy; the ratios rise from 0.40 to 0.92 at room temperature and 0.51 to 0.97 at 1540 °C, as 7.5 wt% of aluminum is doped, and the optimized ceramic cores show high-temperature strengths of 16.6 MPa and 16.1 MPa in different printing directions. Even though ceramic cores with 10 wt% of aluminum show uniform microstructure and higher σ_V/σ_H ratio, the weak particle bonding within printing layers limits their mechanical property, and the strengths decrease to 13.8 MPa and 13.4 MPa at 1540 °C. This work inspires a new technique to excellent high-temperature mechanical properties with anisotropy control in 3D printing of ceramic cores.     

Thin reduced graphene oxide interlayer with a conjugated block copolymer for high performance non-volatile ferroelectric polymer memory

Polymer ferroelectric-gate field effect transistors (Fe-FETs) employing ferroelectric polymer thin films as gate insulators are highly attractive as a next-generation non-volatile memory. For minimizing gate leakage current of a device which arises from electrically defective ferroelectric polymer layer in particular at low operation voltage, the materials design of interlayers between the ferroelectric insulator and gate electrode is essential. Here, we introduce a new solution-processed interlayer of conductive reduced graphene oxides (rGOs) modified with a conjugated block copolymer, poly(styrene-block-paraphenylene) (PS-b-PPP). A FeFET with a solution-processed p-type oligomeric semiconducting channel and ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) insulator exhibited characteristic source–drain current hysteresis arising from ferroelectric polarization switching of a PVDF-TrFE insulator. Our PS-b-PPP modified rGOs (PMrGOs) with conductive moieties embedded in insulating polymer matrix not only significantly reduced the gate leakage current but also efficiently lowered operation voltage of the device. In consequence, the device showed large memory gate voltage window and high ON/OFF source–drain current ratio with excellent data retention and read/write cycle endurance. Furthermore, our PMrGOs interlayers were successfully employed to FeFETs fabricated on mechanically flexible substrates with promising non-volatile memory performance under repetitive bending deformation.     

Highly-rough surface carbon nanofibers film as an effective interlayer for lithium–sulfur batteries

Lithium–sulfur (Li–S) battery with a new configuration is demonstrated by inserting a flexible nitrogen-doping carbon nanofiber (N-CNFs) interlayer between the sulfur cathode and the separator. The N-CNFs film with high surface roughness and surface area is fabricated by electrospinning and a subsequent calcination process. The N-CNFs film interlayer not only effectively traps the shuttling migration of polysulfides but also gives the whole battery reliable electronic conductivity, which can effectively enhance the electrochemical performance of Li–S batteries. Finally, Li–S batteries with long cycling stability of 785 mAh/g after 200 cycles and good rate capability of 573 mAh/g at 5 C are achieved.     

BSE系列耐低温乳化型震源药柱

概述了作药震源在石油、天然气地震勘探中的重要作用与国内现状。阐述了ＢＳＥ系列耐低温乳化型震源药柱的组分选择、品种配方、生产工艺与主要性能,讨论了该系列震源药柱的使用技术与获得的结果,预测了该系列震源药柱对我国地霞勘探技术发展的影响．     

超细膨润土/环氧树脂复合材料的结构与热性能

采用TG-DTA、IR、SEM、马丁耐热和Daniel流动点测定等方法,研究了有机胺改性超细膨润土与环氧树脂的固化体系的结构及其性能。结果表明,有机胺改性膨润土与环氧树脂固化复合后,可形成由层问固化与层外固化相结合的结构,所得复合材料的耐热性能、分散性均有提高,其中活化有机膨润土／环氧树脂复合体系的分散效果和马丁耐热特性改善更加显著。     

Design of diffusion barriers

An exact analytical solution to metal diffusion in a triplet stack consisting of a barrier material layer, an interlayer dielectric, and a semiconductor substrate has been developed. The solution shows how the diffusive behavior of the metal depends on the material properties of the entire system. The resistance of the interconnect system to contamination is not linearly dependent on the material and geometrical properties and some properties, such as the barrier diffusivity and solubility, are significantly more important than others. The model was able to match the copper diffusion data of Shacham-Diamand [J. Electrochem. Soc., 140(8), 2427 (1993)] very well using material properties consistent with the available experimental data.     

Synthesis, characterization and reaction behaviour of lamellar AFm phases with aliphatic sulfonate-anions

The addition of alkanesulfonates as admixtures to cementitious materials allows the formation of new lamellar phases (AFm), which was proofed by X-ray diffraction (XRD). The course of hydration was investigated by heat flow calorimetry.The layered structures of AFm phases are composed of brucite-like main layers and interlayers containing alkanesulfonate ions and additional H₂O molecules. These structural not necessary H₂O molecules release gradually at definite steps with increasing temperature. With varying relative humidity the layer thickness c′ of short aliphatic chained calcium aluminate alkanesulfonate hydrates changes considerably, whereas large organic molecules dominate the layer thickness of those with longer aliphatic chains. By means of the increase of layer thickness with increasing chain lengths it is possible to determine the tilt angles of the aliphatic chains in the interlayers.     

蒙脱石的电子自旋共振研究

对蒙脱石及其改型处理的样品作了电子自旋共振(ESR)研究。结果表明,在蒙脱石的 ESR 谱中有两个主要的特征信号,其 g 值分别为 g_((?)ff)～4.3和2.0。前者对应蒙脱石中 Fe~(3+)离子的强结构信号,后者描述了蒙脱石层间离子相关的信号,它随着不同离子的交换改型而敏感地变化。在样品加热处理后,两者的信号发生了大的变化。这种变化反映了蒙脱石层间离子的构形形态的变化、迁移以及蒙脱石层结构的变化。