There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

In this chapter, we will restrict our attention to the ferrites and a few other closely related materials. The great interest in ferrites stems from their unique combination of a spontaneous magnetization and a high electrical resistivity. The observed magnetization results from the difference in the magnetizations of two non-equivalent sub-lattices of the magnetic ions in the crystal structure. Materials of this type should strictly be designated as “ferrimagnetic” and in some respects are more closely related to anti-ferromagnetic substances than they are to ferromagnetics in which the magnetization results from the parallel alignment of all the magnetic moments present. We shall not adhere to this special nomenclature except to emphasize effects, which are due to the existence of the sub-lattices.

Ferromagnetic materials

Interpretation of X-ray Powder Diffraction Patterns . By H. Lipson and H. Steeple. Pp. viii + 335 + 3 plates. (Mac-millan: London; St Martins Press: New York, May 1970.) £4.

X-Ray Diffraction

Graphite as a potassium ion battery anode in carbonate-based electrolyte and ether-based electrolyte

In this work, the Mg2-xCuxSiO4(x = 0–0.40) microwave dielectric ceramics were prepared using solid-state reaction method. Compared with the Mg2SiO4 sample, the Cu-substituted Mg samples could be sintered at a lower temperature. The Mg2−xCuxSiO4 ceramics exhibit the composite phases of Mg2SiO4 and a small quantity of MgSiO3. The Cu2+ ion presented a solid solution with the Mg2SiO4 phase and preferentially occupy Mg(1) site. The distortion of MgO6 octahedron was modified by Cu2+ ions, resulting in a positive change in the temperature coefficient of resonance frequency (τf) values. Excellent microwave dielectric properties of er = 6.35, high Qf of ∼ 188,500 GHz and near zero τf = −2.0 ppm/°C were achieved at x = 0.08 under sintering at 1250 °C for 4 h. Thus, the fabricated ceramics were considered as possible candidates for millimeter-wave device applications.

Phase composition, crystal structure and microwave dielectric properties of Mg 2− x Cu x SiO 4 ceramics

Transient electronic is an emerging field that designed electronic devices can be fleetly and partially (or completely) degraded when transiency is triggered. Here, a class of PVA-based degradable composite film was synthesized, whose physical properties allow it to be used as substrate material for transient electronic devices. We found the dielectric properties and dissolution rate of the composite film can be tuned by controlling the TiO2 nanoparticle addition. Based on the as-synthesized PVA/TiO2 composite film, patch antennas were further designed and fabricated. The antennas were found to possess excellent radiation performances at a frequency of 2.5 GHz. Most importantly, the antennas could be physically degraded within 1 h when immersed in pure water. This study shows that the PVA-based film is a good candidate substrate or supporting material for transient electronics. In addition, the design and manufacture methods reported here provide a reference for other transient devices with complex structure and function.

Jie Li

Papers

Graphite as a potassium ion battery anode in carbonate-based electrolyte and ether-based electrolyte

Phase composition, crystal structure and microwave dielectric properties of Mg 2− x Cu x SiO 4 ceramics

Controllably degradable transient electronic antennas based on water-soluble PVA/TiO 2 films

Enhanced ferromagnetic properties of low temperature sintering LiZnTi ferrites with Li2O–B2O3–SiO2–CaO–Al2O3 glass addition

Crystal structure and enhanced microwave dielectric properties of Ta5+ substituted Li3Mg2NbO6 ceramics