铁基合金的贝氏体基元及其生长演化

用透射电镜研究了 Fe-C-Mo 和 Fe-C-Si-Mn 合金中温转变早期产物的组织形态,发现在整个中温转变范围非平衡先析型转变都是按贝氏体铁素体相变基元形成及其扩散生长演化方式进行,说明经生长演化一些时间后的基元难于作为判断贝氏体形核机制的形态学依据。从基元生长演化进程区分了低碳贝氏体和板条马氏体。     

The thermochemical behavior of some binary shape memory alloys by high temperature direct synthesis calorimetry

The standard enthalpies of formation of some shape memory alloys have been measured by high temperature direct synthesis calorimetry at 1373 K. The following results (in kJ/mol of atoms) are reported: CoCr (−0.3 ± 2.9); CuMn (−3.7 ± 3.2); Cu₃Sn (−10.4 ± 3.1); Fe₂Tb (−5.5 ± 2.4); Fe₂Dy (−1.6 ± 2.9); Fe₁₇Tb₂ (−2.1 ± 3.1); Fe₁₇Dy₂ (−5.3 ± 1.7); FePd₃ (−16.0 ± 2.7); FePt (−23.0 ± 1.9); FePt₃ (−20.7 ± 2.3); NiMn (−24.9 ± 2.6); TiNi (−32.7 ± 1.0); TiPd (−60.3 ± 2.5). The results are compared with some earlier experimental values obtained by calorimetry and by EMF technique. They are also compared with predicted values on the basis of the semi empirical model of Miedema and co-workers and with ab initio calculations when available. We will also assess the available information regarding the structures of these alloys.     

Crystallization and infrared radiation properties of iron ion doped cordierite glass-ceramics

Heterogeneous ion solution is an important method to improve the wanted property of polycrystalline materials. In this paper, for the purpose of infrared radiation property modification, different contents Fe₂O₃ were doped in MgO-Al₂O₃-SiO₂ system glasses. The effects of Fe₂O₃ doping on nucleation mechanism, crystallization behaviors and especially infrared radiation properties of this cordierite-crystalline based glass-ceramics were systematically investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results show that, the doping of iron ion can promote the phase separation of this magnesium aluminosilicate glass, and therefore change the crystallization mechanism of this glass from surface crystallization to bulk crystallization. The iron ion incorporates into the crystal structure of cordierite by mean of substituting Mg²⁺ in M site. The substitution of Fe³⁺ to Mg²⁺ can form the vacant site of Mg²⁺ cations. For the effects of lattice distortion, impurity and vacancy defects which caused by the incorporation of iron ion, the infrared radiation performance of cordierite based glass-ceramics can be improved effectively.     

四方相BaTiO3薄膜的自组装制备与表征

以(NH₄)₂TiF₆、 Ba(NO₃)₂ 和H₃BO₃为主要原料, 采用自组装单层膜(SAMs)技术, 以三氯十八烷基硅烷(octadecyl-trichloro-silane, OTS)为模版, 在玻璃基片上制备了四方相钛酸钡晶态薄膜. 改性基板的亲水性测定与原子力显微镜（AFM）测试表明, 紫外光照射使基板由疏水转变为亲水, 能够对OTS-SAM起到修饰作用. 金相显微镜观察结果显示,OTS单分子膜指导沉积的薄膜样品表面均匀, 表明OTSSAM对钛酸钡薄膜的沉积具有诱导作用; X射线衍射（XRD）与扫描电镜（SEM）表征显示, 空气中600℃下保温2h实现了薄膜由非晶态向四方相BaTiO₃晶态薄膜的转化过程, 制备的钛酸钡薄膜在基板表面呈纳米线状生长, 线长约在500～1000nm之间, 相互连接的晶粒大小约为100nm. 文章同时对自组装单层膜和钛酸钡薄膜的形成机理进行了探讨.     

汽车起动用铅酸蓄电池化成半化率的讨论及研究

实验研究极板化成装板后浸泡时间对汽车起动用铅酸蓄电池化成半化率的影响。通过比较充电前浸泡时间分别为10 min、20 min、30 min、40 min、50 min、60 min后的极板半化率,得出结论极板浸泡30 min开始充电极板半化率最低。     

Formation Theory and Printability of Photocurable Hydrogel for 3D Bioprinting

Bio-ink has gradually transited from ionic-crosslinking to photocrosslinking due to photocurable bio-hydrogel having good formability and biocompatibility. It is very important to understand and quantify the crosslinking process of photocurable hydrogels, otherwise, bioprinting cannot be standardized and scalable. However, there are few studies on hydrogel formation process and its photocrosslinking behavior which cannot be accurately predicted. Herein, the photoinitiated radical polymerized bio-hydrogels are taken as an example to establish the formation theory. Three typical crosslinking reactions are first distinguished. It is further proposed that not all double-bonds consumed during crosslinking contributeequally to polymerization. Then the concept of effective double-bond conversion (EDBC) is elicited. Deriving from EDBC, several important formation indices are defined. According to theory, it is predicted that slow crosslinking can improve the crosslinking degree. Furthermore, based on the slow crosslinking effect, a new strategy of projection-based 3D printing (PBP) is proposed, which significantly improved printing quality and efficiency. Overall, this work will fill the gap in hydrogel's formation theory, making it possible to accurately quantify the formation process.     

Going from green to white color electroluminescence through a nanoscale complex of Zinc (II)

In this paper, we report application of four novel Nano Zinc (II) complexes as the emitter dyes in organic light emitting diodes (OLEDs). The Nano Zinc (II) complexes emission, particularly its absorption, fluorescence spectra and quantum yield, tuned by varying sizes which affects environments of the Zinc (II) ion. OLED Devices with Nano Zinc (II) complexes were fabricated, giving rise to devices with peak emission ranging from 498 to 541 nm. Here, we have successfully employed sonoelectrochemical method for fabricating white OLEDs. The white emission ascribed to the exciton emission in Nano Zinc (II) complex emitter and from exciplex formation at the interface of PVK/Nano Zinc (II) complex. The experimental results demonstrate that this approach is ideal for color tuning of single and multilayer conducting semiconducting thin films used in the fabrication of organic electronic devices such as OLEDs.     

Circumventing Dedicated Electrolytes in Light‐Emitting Electrochemical Cells

Light‐emitting electrochemical cells (LECs) are devices that utilize efficient ion redistribution to produce high‐efficiency electroluminescence in a simple device architecture. Prototypical polymer LECs utilize three components in the active layer: a luminescent conducting polymer, a salt, and an electrolyte. Similarly, many small‐molecule LECs also utilize an electrolyte to disperse salts. In these systems, the electrolyte is incorporated to efficiently conduct ions and to maintain phase compatibility between all components. However, certain LEC approaches and materials systems enable device operation without a dedicated electrolyte. This review describes the general methods and materials used to circumvent the use of a dedicated electrolyte in LECs. The techniques of synthetically coupling electrolytes, incorporating ionic liquids, and introducing inorganic salts are presented in view of research efforts to date. The use of these techniques in emerging classes of light‐emitting electrochemical cells is also discussed. These approaches have yielded some of the most efficient, long‐lasting, and commercially applicable LECs to date.     

Morphology Transformation Pathway of Block Copolymer-Directed Cooperative Self-Assembly of ZnO Hybrid Films Monitored In Situ during Slot-Die Coating

Cooperative self-assembly (co-assembly) of diblock copolymers (DBCs) and inorganic precursors that takes inspiration from the rich phase separation behavior of DBCs can enable the realization of a broad spectrum of functional nanostructures with the desired sizes. In a DBC assisted sol–gel chemistry approach with polystyrene-block-poly(ethylene oxide) and ZnO, hybrid films are formed with slot-die coating. Pure DBC films are printed as control. In situ grazing-incidence small-angle X-ray scattering measurements are performed to investigate the self-assembly and co-assembly process during the film formation. Combining complementary ex situ characterizations, several distinct regimes are differentiated to describe the morphological transformations from the initially solvent-dispersed to the ultimately solidified films. The comparison of the assembly pathway evidences that the key step in the establishment of the pure DBC film is the coalescence of spherical micelles toward cylindrical domains. Due to the presence of the phase-selective precursor, the formation of cylindrical aggregates in the solution is crucial for the structural development of the hybrid film. The pre-existing cylinders in the ink impede the domain growth of the hybrid film during the subsequent drying process. The precursor reduces the degree of order, prevents crystallization of the PEO block, and introduces additional length scales in the hybrid films.     

切换通信拓扑条件下的无人机集群构型变换控制

研究了在切换通信拓扑条件下的无人机集群构型变换控制问题。基于一致性控制理论,对具有2阶积分特性的无人机集群设计了构型变换控制协议,为使无人机集群能够实现特定构型变换并保持特定速度,在控制协议中引入编队参考向量。给出了在通信拓扑切换情况下无人机集群实现特定构型变换并保持特定速度的充分必要条件。在通信拓扑图保持连通的条件下,利用Lyapunov稳定性理论证明了无人机集群系统稳定性,并利用代数黎卡提方程理论给出了控制协议中参数矩阵的设计方法。数值仿真结果验证了所设计的控制协议有效性。