Annealing or direct synthesis of uniform inorganic nanoparticles using salt powder as separation medium

Uniform nanoparticles have shown to hold great potential in many different fields. As a result, many resources have been devoted to the search for a general synthesis of uniform nanoparticles, which has led to the proliferation of solution-based methods. However, some of these techniques are inherently difficult to scale up and are unable to meet future industry needs. Additionally, since the synthesis temperature of these methods can only go as high as the evaporation point of the solvent, they are not compatible with the high temperatures required to obtain certain desired properties such as high crystallinity. Recently, solventless methods have gained considerable attention since they are relatively fast and require no expensive or toxic solvents. Inorganic salt powder can be used as separation medium to prevent aggregation and sintering by keeping the as-prepared nanoparticles or precursor materials physically separated. This review surveys the use of inorganic salts in solventless techniques for the annealing or direct synthesis of uniform nanoparticles.

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Graphical abstract Fine inorganic salt powder can be used as separation medium to prevent aggregation and sintering by keeping the as-prepared nanoparticles or precursor materials physically separated. The primary advantages of this strategy are its simplicity and the ability to easily scale-up. Additionally, this strategy can use a wider temperature window compared to solution-based syntheses. Lastly, the inorganic salt powder can be separated and reused by washing the final nanomaterials. This review surveys the use of inorganic salts in solventless techniques for the annealing or direct synthesis of uniform nanoparticles.

     

多符号差分酉空时系统的低复杂度M算法设计

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近期南海远程声传播实验数据的处理分析表明在深海不完整声道中声道轴以下存在一种会聚区,该会聚区相比于海面附近的上反转点会聚区在远距离处具有更高的会聚增益.本文利用射线简正波理论确定了水中反转型焦散线和海面反射型焦散线位置,对比发现实验中观测到的深海大深度会聚区位置与水中反转型焦散线位置一致,证明该会聚区是由大量简正波同相...     

高效液相色谱法检测氟吗啉在土壤中的降解

建立了氟吗啉在土壤中残留分析的高效液相色谱(HPLC)检测方法,在实验室条件下对氟吗啉在我国具有代表性的3种土壤中的降解动态进行了研究。样品通过V(正己烷)∶V(乙酸乙酯)=1∶2混和溶液萃取,经弗罗里硅土SPE柱净化,浓缩后进行HPLC检测。结果表明,药剂土壤添加浓度在0.2和2.0mg/kg时,氟吗啉在不同土壤中回收率为78.8%～97.1%;标准偏差为2.24%～7.48%。氟吗啉在土壤中的降解遵循一级动力学方程;氟吗啉在3种土壤中的降解速率大小依次为黑龙江黑土>江西红土>河南黄土,其降解半衰期分别为99.02、106.64和157.53d,降解速率常数(k)分别为7.0×10-3、6.5×10-3和4.4×10-3。根据国内农药在土壤中的残留划分标准,氟吗啉属于中等降解类农药。比较氟吗啉在非灭菌与灭菌的黑龙江黑土、江西红土和河南黄土中的降解情况表明,药剂在非灭菌土中降解明显快,分析可能是土壤中微生物对氟吗啉的降解具有显著的影响。     

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缺乏有效的误差补偿方法足制约长光栅测最精度提高的关键原因之一.提出一种动态的误差补偿方法.可以消除由直流漂移、两路信号不等幅和非止交导致的细分误差.其原理是跟踪光栅信号在一个周期上的8个特征值点(正余弦信号的过零点及绝对值交点),从特征值点的幅度值中首先分解出正弦信号的直流漂移误差.对其进行补偿;然后继续跟踪补偿后的信号.从中义能分解出余弦信号的直流漂移误差.再补偿.再跟踪.又能依次分解出不等幅误差和非正交误差.最多只需要3个光栅信号周期,就能对三种误差依次实现补偿.分析了谐波对该方法的影响并提出r改进措施.实验证实了该方法的有效性.     

Synthesis of Cu3Sn Alloy Nanocrystals through Sequential Reduction Induced by Gradual Increase of the Reaction Temperature

Cu₃Sn alloy nanocrystals are synthesized by sequential reduction of Cu and Sn precursors through a gradual increase of the reaction temperature. By transmission electron microscopy (TEM), energy‐dispersive X‐ray spectroscopy (EDS), UV/Vis spectroscopy, and X‐ray diffraction (XRD) analyses, the alloy formation mechanism of Cu₃Sn nanocrystals has been studied. The incremental increase of the reaction temperature sequentially induces the reduction of Sn, the diffusion of Sn into the preformed Cu nanocrystals, resulting in the intermediate phase of Cu–Sn alloy nanocrystals, and then the formation of Cu₃Sn alloy nanocrystals. We anticipate that the synthesis of Cu₃Sn alloy nanocrystals encourages studies toward the synthesis of various alloy nanomaterials.     

掺CdS_xSe_（1－x）玻璃波导分布反馈光学双稳器件

本文给出了掺ＣｄＳ_ｘＳｅ_(１－ｘ)玻璃平面波导分布反馈（ＤＦＢ）光学双稳器件的设计和制备方法，实现了低功耗、快速的本征光学双稳。     

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通过采用扫描行负反馈法，提高了选通电压差，使对比度得到提高。相对于同样对比度的情况下，克服了交叉干扰。