A method to fitting the magnetic field of a plate magnet.

I find I make wrong table in my paper (Soft electromagnetic actuators), here I try to correct it.

In the paper, we use a plate magnet (Fig. S3A, with a diameter=10 cm and height=3 cm, N45 coated with Nickel) which can be purchased via the link(www.magnet-shop.com).

At first, we use a Gauss meter (Gaussmeter HGM09s, Goudsmit Magnetic Systems) to measure the magnetic field. Then we fitting the experimental data with Comsol (Fig. S3B& Fig. S3C). Only one parameter needs to fit, the remnant magnetization.

From the manufacture, we obtain the remnant magnetization is 1.32-1.37 T. We obtain the remanent magnetization of the plate magnet, 1.31 T from fitting (Fig. S3D). It can use a simple equation to fit the magnetic field at the center of the magnet where R=0 (Fig. S3E).

Also we can know the distribution of the magnetic field from simulation(Crosection: Fig. S3 F&G, Field: Fig. S3H&I). With Matlab (lsqcurvefit, or fit) we are able to fitting the magnetic field with the following equations:

The parameter P and Q are not correct in the paper (Table S1) which comes from a unknow version even thou it can generate a similar magnetic field, here I provide the orginal data (Matlab code and data) and the program to plot the Fig. S3 F,G,H,I:

Fig. S3. Characterization of a plate magnet. (A) Picture of the plate magnet. (B) Simulated spatial distribution of the magnetic field around a plate magnet. The legend shows the strength of the magnetic potential. (C) Measurements of the magnetic field were taken at the labeled sites 6 mm above the surface of the magnet. (D) Comparison of magnetic flux density between the experimental measurement and the simulation corresponding to the labeled sites in (C). (E) Simulated and fitted magnetic flux density along the symmetry axis of the magnet at R=0. (F&G) Distribution of the two components of the magnetic field at different heights Z above the surface of the magnet. (H&I) Contour maps of a 3D numerical fitting of the magnetic field on the top of the plate magnet compared with the simulated results. (Photo Credit: Michael Drack and Guoyong Mao/Johannes Kepler University Linz)

Made in China in a view of a researcher

While reading a paper, I got a intresting finding. The paper is about a magnetic refrigerant bought from a chinese company Baotou Steel and Rare Earth Company of China. In a section, the researcher anaylsed the elements of the material. Even tough the company claimed it is 99.9% pure, but actually it is 93% (99.7% wt.%) which is not so pure. Then its performance is slightly inferior to the data from Ames Laboratory. However, then the researcher compared the price of the Chinese material with the material used in the Ames Laborotory, which are $110/kg and $23,000/kg, respectively. Very happy to use chinses product.

original short-cut.

paper: Zimm, C., A. Jastrab, A. Sternberg, V. Pecharsky, K. Gschneidner, M. Osborne, and I. Anderson. “Description and performance of a near-room temperature magnetic refrigerator.” In Advances in cryogenic engineering, pp. 1759-1766. Springer, Boston, MA, 1998.


materials for renewing residence permit 拘留延期申请需要办理的材料。摄制于2019年9月
  1. 护照# 需要护照首页,理论上所有含有信息的页面都需要复印,但是签证官也没有看。
  2. 照片。 3.5×4.5 cm,#最好带有日期的照片,6个月内。
  3. 租赁合同 #租房,如果住房地址没有更换的话,理论上不需要
  4. 健康保险说明(一般在合同中), 带上E-card(for insurance) #研究人员的保险合同
  5. 工作合同(保证自己能在奥地利生活下去)#工作合同中有工资说明
  6. 最近三个月的工资单,要求单位打印出的。银行的收入history并没有用。
  7. 带上之前的ID card
  8. 被要求 Hosting Agreement,主要由单位出具,接收证明(如果是project post-doc申请researcher type的residence permit那么这个是必须的。如果是University assistant, 那么就不需要这个, 学校不提供,而且签证类型改为 Settlement permit special cases of gainful employment)。
  9. KSV-AUszug (非必要的认证,从来没有过。)# 类似蚂蚁信用的东西,没什么用。




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