含强约束界面片状夹杂复合陶瓷热膨胀系数预报

以含强约束界面相片状夹杂复合陶瓷的细观结构为基础,建立含片状夹杂、强约束界面相、基体氛围和有效介质组成的四相模型,将片状夹杂、强约束界面相和基体氛围构成的三相胞元看作复合夹杂,根据Eshelby理论,确定了含同向片状夹杂复合陶瓷的有效热膨胀系数的解析表达式,复合陶瓷为横观各向同性,有2个独立的热膨胀系数.定量分析表明含同向片状夹杂的强约束界面复合陶瓷的有效热膨胀系数具有明显的尺度效应.     

Stiffness-Transformable Nanoplatforms Responsive to the Tumor Microenvironment for Enhanced Tumor Therapeutic Efficacy

Herein, we report, for the first time, a unique stiffness-transformable manganese oxide hybridized mesoporous organosilica nanoplatform (MMON) for enhancing tumor therapeutic efficacy. The prepared MMONs had a quasi-spherical morphology and were completely transformed into soft bowl-like nanocapsules in the simulated tumor microenvironment through the breakage of Mn−O bonds, which decreased their Young's modulus from 165.7 to 84.5 MPa. Due to their unique stiffness transformation properties, the MMONs had reduced macrophage internalization, improved tumor cell uptake, and enhanced penetration of multicellular spheroids. In addition, in vivo experiments showed that the MMONs displayed a 3.79- and 2.90-fold decrease in non-specific liver distribution and a 2.87- and 1.83-fold increase in tumor accumulation compared to their soft and stiff counterparts, respectively. Furthermore, chlorin e6 (Ce6) modified MMONs had significantly improved photodynamic therapeutic effect.     

草酸盐沉淀法制备超细氧化铈的研究

研究了草酸盐沉淀法制备超细氧化铈粉体的工艺.通过正交实验,研究了沉淀方式、沉淀剂的浓度、硝酸铈的浓度、反应温度、滴加速度等沉淀条件对氧化铈颗粒粒径的影响,找出了制备纳米氧化铈的最佳沉淀工艺条件.利用DTA/TG对氧化铈样品前驱体的热分解行为进行了分析,研究了培烧和干燥条件对氧化铈粒径和比表面积的影响,由此确立了制备氧化铈合适的焙烧和干燥条件.结果表明采用草酸盐反向沉淀法可以得到超细氧化铈粉体,其体积中心粒径D50为1.011μm、比表面积为42.69m2·g-1,晶体结构为立方晶系,CAF2萤石型结构,形状呈薄片状,分散性较好.     

Application of dynamic speckle method using in sedimentation process of silver chloride

The generation process of silver chloride was studied using dynamic speckle methods including speckle size measurement and speckle contrast measurement. The quantity and size changes of the sedimentation particles in the illuminating region were investigated and analyzed.     

共晶基陶瓷复合材料的断裂韧性

应用细观力学方法研究了由具有随机尺寸和方位的棒体共晶体构成的共晶基陶瓷复合材料的断裂韧性.首先根据棒状共晶体的细观结构特性,考虑共晶体边界处的微观滑移确定共晶陶瓷复合材料的开裂应力,当外载荷达到开裂应力时,裂纹开始扩展.然后分析裂纹表面处的棒状共晶体桥联力使裂纹产生闭合效应,减小裂纹尖端的应力集中,建立棒状共晶体桥联增韧机制;再依据棒状共晶体拔出过程中摩擦力做功,建立棒状共晶体拔出增韧机制.最后在棒状共晶体的桥联与拔出增韧机制的基础上,得到了共晶基陶瓷复合材料断裂韧性的理论表达式.结果表明共晶基陶瓷复合材料的断裂韧性与棒状共晶体的长径比密切相关.     

Evidence for visible quantum cutting via energy transfer in SrAl12O19:Pr,Cr

Evidence for visible quantum cutting involving the emission of two visible photons for each vacuum-ultraviolet (VUV) photon absorbed is demonstrated in SrAl(12)O(19):Pr,Cr using synchrotron radiation as one of the excitation sources. Upon VUV excitation of the 4f5d states of Pr(3+), quantum cutting could occur by a two-step energy transfer from Pr(3+) to Cr(3+) by cross relaxation and sequential transfer of the remaining excitation energy. A theoretical visible quantum efficiency of 147% is estimated in SrAl(12)O(19):2% Pr,5% Cr, suggesting the possibility of a VUV phosphor with visible quantum efficiency higher than 100% based on Pr(3+)-Cr(3+) pair in oxide materials.     

Generation of Circular Optical Vortex Array

We report on a novel optical vortex array named circular optical vortex array, which is generated by the superposition of two concentric perfect optical vortices. The circular optical vortex array has a constant topological charge of +1 or ?1, the number and sign of which are determined by the topological charges of the two perfect optical vortices. Moreover, the radius of the circular optical vortex array is easily adjusted by using the cone angle of an axicon. Furthermore, the circular optical vortex array and multiple circular optical vortex array can be rotated by changing the initial phase difference of the perfect optical vortices on demand. This work demonstrates a complex structured optical field, which is of significance for applications such as optical tweezers, micro‐particle manipulation, and optical imaging.     

One‐Step Synthesis of Natural Silk Sericin‐Based Microcapsules with Bionic Structures

Different techniques are being developed for fabricating microcapsules; it is still a challenge to fabricate them in an efficient and environment‐friendly process. Here, a one‐step green route to synthesize silk protein sericin‐based microcapsules without any assistance of organic solvents is reported. By carefully changing the concentration of calcium ions accompanied with stirring, the morphology of the microcapsules can easily be regulated to form either discoidal, biconcave, cocoon‐like, or tubular structures. The chelation of Ca²⁺ and shearing force from agitation may induce the conformational transformation of sericin, which possibly results in the formation of microcapsules through the self‐assembly of the protein subsequently. The as‐prepared cocoon‐like microcapsules exhibit pH‐dependent stability. A potential application of microcapsules being fabricated from natural water‐soluble silk protein sericin for controlled bioactive molecules loading and release system by a pH‐triggered manner is quite feasible.

     

Deformable double-shelled hollow mesoporous organosilica nanocapsules:A multi-interfacial etching strategy

Multishelled hollow structures have drawn increasing interest because of their peculiar compartmentation environments and physicochemical properties.In this work,deformable double-shelled hollow mesoporous o rganosilica nanocapsules(DDHMONs) were succes s fully synthesized by a multi-interfacial etching strategy.The obtained DDHMONs have a double-shelled structure with aninorganic-organic hybrid framework,a uniform outer layer(～320 nm) and inner layer(～180 nm),ordered mesochannels(～2.21 nm),and a large specific surface area(～1233 m~2/g).In vitro toxicity tests show that the DDHMONs have excellent biocompatibility when coincubated with human breast cancer cells.In addition,the anti cancer substance doxorubicin(DOX) can be highly loaded in DDHMONs(～335 μg/mg).The results from flow cytometry together with confocal laser scanning microscopy show that DOX can be efficiently delivered into MCF-7 cells by DDHMONs,thus improving chemotherapeutic efficiency and demonstrating that DDHMONs have potential nanomedicine applications as anticancer agents.