基于MOF (Cu)@biochar气凝胶的制备及其在缓释氮肥上的应用

以羧甲基纤维素(CMC)、明胶和MOF(Cu)@biochar为原料,采用简单有效的冷冻干燥方法制备了(CMC/Gelatin/MOF(Cu)@biochar)杂化气凝胶,并用傅里叶变换红外光谱(FT-IR)、热重分析(TG)、X射线粉末衍射(XRD)、扫描电镜(SEM)和X射线光电子能谱(XPS)技术对其进行了表征;研究了MOF(Cu)@biochar含量、pH和不同的盐水溶液对杂化气凝胶溶胀行为的影响;以该气凝胶负载氯化铵,制备了一种新型缓释肥料(SRF),并研究了含2%(wt)SRF的沙性土壤的保水能力;SRF在土壤中第30天的累积释放率为79.4%;肥料在土壤中释放符合非Fickian扩散和阳离子交换的协同作用机理。     

基于不确定控制理论的最优策略研究

本文在不确定理论的框架下,研究一类带背景状态变量的最优控制模型.在乐观值准则下,利用不确定动态规划的方法,证明了不确定最优性原则,得到最优性方程.作为应用,求解一个固定缴费(DC)型养老金的最优投资策略问题,在乐观值准则下,以工资变量为背景状态变量,建立养老金模型.通过求解不确定最优性方程得到最优投资策略和最优支付率.     

Flow-induced shear stress and deformation of a core–shell-structured microcapsule in a microchannel

A numerical model was developed and validated to investigate the fluid–structure interactions between fully developed pipe flow and core–shell-structured microcapsule in a microchannel. Different flow rates and microcapsule shell thicknesses were considered. A sixth-order rotational symmetric distribution of von Mises stress over the microcapsule shell can be observed on the microcapsule with a thinner shell configuration, especially at higher flow rate conditions. It is also observed that when being carried along in a fully developed pipe flow, the microcapsule with a thinner shell tends to accumulate stress at a higher rate compared to that with a thicker shell. In general, for the same microcapsule configuration, higher flow velocity would induce a higher stress level over the microcapsule shell. The deformation gradient was used to capture the microcapsule's deformation in the present study. The effect of Young's modulus on the microcapsule shell on the microcapsule deformation was investigated as well. Our findings will shed light on the understanding of the stability of core–shell-structured microcapsule when subjected to flow-induced shear stress in a microfluidic system, enabling a more exquisite control over the breakup dynamics of drug-loaded microcapsule for biomedical applications.     

Majorana Representation for a Composite System

International Journal of Theoretical Physics - The Majorana representation, which provides an intuitive way to represent the quantum state by stars on the Bloch sphere, has drawn considerable...     

MCNOs/CdS双效光催化剂的制备及其性能研究

水热合成法制备了不同磁性纳米洋葱碳(MCNOs)负载量(0%、1%、3%、5%)的MCNOs/CdS光催化剂。并通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)、傅里叶红外光谱(FT-IR)、X射线光电子能谱(XPS)、紫外可见光光谱(UV-Vis)、磁滞回线测定仪(VSM)对其进行表征,探究了MCNOs负载比例对催化剂在可见光下降解RhB性能及机理的影响。结果表明,MCNOs能有效提高CdS的光催化效果,复合3%MCNOs后降解率为96%,与纯CdS相比降解率提高了30%,磁性分析表明,其具有良好的顺磁性并能实现催化剂的有效回收。MCNOs/CdS在可见光下催化降解RhB的一级反应动力学直线有较好的拟合度,表明制备的催化剂有较好的催化活性。     

利用沙漠沙低温合成高长径比莫来石晶须

利用沙漠沙独特的化学组成特性和矿物特性,将沙漠沙荒料作为硅源,工业Al(OH)3作为铝源制备莫来石晶须.改变硅源/铝源配比和合成温度,结合XRD、SEM、TEM研究莫来石生长环境和自由生长形态的变化.研究结果表明:当沙漠沙与Al(OH)3的质量比为35/65时,在1200℃的低温下就能获得平均值>60的高长径比莫来石晶须;随着煅烧温度的升高,莫来石晶须长径比不断增大,当温度升至1300℃,平均长径比>94.随着合成温度的升高,莫来石的形成经过了一次莫来石和二次莫来石化两个阶段;若配方中Al2 O3处于过饱和状态,样品中刚玉相会随着煅烧温度的升高出现先增多后降低的变化现象.     

Preparation and gas sensing activity of La and Y co-doped titania nanoparticles

Journal of Sol-Gel Science and Technology - A novel gas sensing material, La–Y co-doped TiO2 nanoparticles, was synthesized by sol–gel method and applied to detect organic pollutants...     

烧结温度对煤系高岭土制备堇青石陶瓷的影响

我国的煤系高岭土具有明显的资源优势,应对其进行充分地研究和合理地应用,以缓和优质高岭土资源枯竭的燃眉之急.以鄂尔多斯煤系高岭土、鄂尔多斯滑石、工业氧化铝为原料,通过反应烧结一步合成堇青石,探讨了堇青石合成温度范围,以拓宽该煤系高岭土的应用范围.通过高温显微镜观察堇青石试样的合成温度范围为1400～1420℃.经1420℃合成的堇青石试样的吸水率为16.11;,显气孔率为28.44;,体积密度为1.77 g/cm3,径向烧成收缩为1.77;,厚度烧成收缩为4.80;,抗折强度为43.56 MPa.镁铝尖晶石是合成堇青石的重要中间产物,适当提高烧结温度可以促进镁铝尖晶石相向堇青石相转变,有利于堇青石晶粒的生长与发育.烧结温度的变化是堇青石晶粒发生变化的原因,同时导致液相量的变化,最终影响堇青石试样显微结构和烧结性能.