2024年10月15日 · In summary, during the in situ TEM heating experiments spanning temperatures from 20 to 120 °C, the ferroelectric domains of the KNN single crystal exhibit notable thermal stability. Thus, the stability of strain performance is inferred to stem from the stability of the O phase ferroelectric domains within this temperature range.

2023年5月15日 · In this study, we observed the evolution of the ferroelectric domain structure of K 0.5 Na 0.5 NbO 3 single crystal (KNN sc) in situ using (scanning) transmission electron microscopy-(S)TEM, in a new generation of capacitor-like configuration that provides, above all, a relatively homogeneous electric field distribution. 10–12 We explored the complex domain structure of KNN sc and ...

Reversible non-180° domain switching is believed to be able to enhance the electromechanical performances of piezoelectrics. However, the slow improvement of strain performances of (K,Na)NbO 3 (KNN) is caused by an inadequate understanding of reversible non-180° domain switching. Here, with an electric field-available sample holder, we directly observe the reversible domain wall motion by in ...

2023年12月1日 · In addition, the electric-field-induced intermediate phase emerges for KNN-based ceramics with two-phase coexistence by means of in-situ transmission electron microscope (TEM) and corresponding fast Fourier transform (FFT) analysis. Through the systemic study on the evolution of domain configuration and crystal structure, we get a deeper ...

2024年6月1日 · KNN-T 1 and KNN-T 2 matrix powders were synthesized using conventional solid state reaction method. High purity K 2 CO 3 (99 %, Alfa Aesar), ... (TEM, FEI Talos F200X, USA). 2.3. Property measurements. Prior to the electrical measurements, silver electrodes were printed onto both surfaces of the samples. The temperature dependence of dielectric ...

2024年10月18日 · c TEM images for the 3T ceramics. ... The KNN-BNZ-xBKH matrix powders pressed into disks of 12-mm diameter and 1-mm thickness under the pressure of 200–300 MPa with a binder of 6 wt% polyvinyl ...

2017年4月3日 · 结合xrd-rsm、tem和pfm的分析，我们的样品的结晶相被确定为菱面体，其具有沿[111]方向的自发极化。 ... (knn-bz-bnt) 薄膜生长在不同取向的 nb 掺杂的 srtio3 衬底上。根据单晶衬底的取向，薄膜显示出高度优先的取向。

A common domain structure of the KNN sc, investigated by TEM in [100] pc,isshowninFig. 1. Generally, three characteristic features canbe seenina [100] pc-orientedspecimen:irregularlyshapedfeatures

2018年1月16日 · (c) knn-0t和knn-3t样品的(001)晶面间距及晶格畸变度随极化电场强度的变化； (d) 外电场作用下从菱方相的[111]自发极化矢量到正交相的[101]自发极化矢量的可能的极化翻转路径示意图； 图4. 织构陶瓷的tem分析 (a) 织构陶瓷的晶粒的低倍率tem明场像；

Here, we synthesized Li-doped KNN ceramics. The morphologies and crystallographic parameters of the domain structures were characterized. Two ferroelectric domains, the 60 /120 and ... TEM photographs of a KNLN grain; the left-bottom inset of (e) shows the selected electron diffraction patterns in the [001] direction, while the top-right inset ...

Download scientific diagram | (a,b) TEM micrographs of aligned KNN nanofibers annealed at 600 °C, (c) SAED pattern acquired from the marked area in panel (b) along the <111> zone axis. (d,e) TEM ...

TEM can be used for the imaging of domains, domain walls, and local phase distribution in different piezoelectric ceramics, including BFO and KNN [69,70]. Contrast in this method is provided by different mechanisms, such as the scattering of high energy electrons in the local electric and stress fields [ 71 ].

2019年8月26日 · Potassium-sodium niobate K 1-x Na x NbO 3 (KNN) is one of the most promising lead-free piezoelectric materials. While there have been many studies on the microstructures and properties of KNN ceramics, the phase transitions and ferroelectric domain structures of KNN thin films are not well understood.

2024年6月22日 · k近邻算法，k Nearest Neighbor(KNN)，它的工作原理如下： 存在一个样本数据集合，也称作训练样本集，并且样本集中每个数据都存在标签，即我们知道样本集中每一数据与所属分类的对应关系。当输入没有标签的新数据后，将新数据的每个特征与样本集中数据对应的特征进行比较，然后算法提取样本 ...

2024年3月5日 · KNN-based ceramics with high dielectric relaxation, good energy storage density and excellent temperature stability were obtained. Ba and Bi elements are conducive to the spontaneous polarization of ceramics, while Zn promotes favorable sintering behavior. ... (TEM, Tecnai G2). The grain morphology of the samples has been studied by a Scanning ...

为用户产生推荐时，从用户节点出发在图上遍历，综合其他用户的喜好为该用户推荐商品。相比于接下来要提到的KNN邻居算法，该方法利用了其他用户的信息，即使是那些没有给Item打分的用户。而KNN 近邻算法 只考虑了离着最近的几个用户。 User-based协同过滤

2024年12月16日 · O KNN tem muitas aplicações práticas, especialmente em situações que envolvem proximidade ou similaridade entre dados. Aqui estão exemplos distintos e específicos: Análise de Preferências em E-commerce: Caso real: Identificar produtos similares aos que o cliente visualizou ou comprou. O KNN pode sugerir itens com base em ...

2024年6月5日 · 文章浏览阅读3k次，点赞12次，收藏28次。在这篇博客中，我们将详细介绍如何使用knn（k最近邻）模型进行数据分析和预测。我们将从导入数据开始，然后选择特征变量，划分训练集和测试集。接着，我们将训练knn模型，进行预测，并计算混淆矩阵、准确率、精确度、召 …

O KNN (K-nearest neighbors, ou "K-vizinhos mais próximos") costuma ser um dos primeiros algoritmos aprendidos por iniciantes no mundo do aprendizado de máquina. O KNN é muito utilizado em problemas de classificação, e felizmente é um dos algoritmos de machine learning mais fáceis de se compreender. Em resumo, o KNN tenta classificar cada amostra de

Para fazer isso, o KNN tem alguns requisitos: Determine suas métricas de distância. Para determinar quais pontos de dados estão mais próximos de um ponto de consulta específico, é necessário calcular a distância entre o ponto de consulta e os outros pontos de dados. Essas métricas de distância ajudam a formar limites de decisão, que ...