High current density Sc2O3-W matrix dispenser cathode

Abstract

Sc 2 O 3 -W matrix dispenser cathodes have been prepared by powder metallurgy method and tested in Pierce electron guns. The emission current density can reach 72 A/cm 2 at 900 • C and over 100 A/cm 2 can be achieved at a temperature higher than 950 • C. The emission improves and then keeps stable with time throughout the life testing period of 330 h at a continuous loading of 88 A/cm 2 pulsed current density with a pulse width of 10 μs and duty cycle of 0.2%. The cathode surface is covered by a semiconductor multilayer composed of Ba, Sc and O. The emission behavior of the cathode can be explained by a semiconductor model. CitationWang J S, Zhang X Z, Liu W, et al. High current density Sc2O3-W matrix dispenser cathode. Sci China Inf Sci, 2012, 55: 98-105,

Dual‐responsive shape memory hydrogels with self‐healing and dual‐responsive swelling behaviors

“…The straight sample was bended into a U‐form, and then soaked in 0.1 M FeCl 3 solution for 24 h to lock the provisional U‐form. When the U‐shaped hydrogel was soaked in pure water or exposed to air, the U‐form could be maintained, without restoring to its initial straight‐form (Figure S1), manifesting the outstanding network retention and shape fixing capability of electrostatic interaction between –COO − and Fe 3+ 69 . Meanwhile, endowed by Fe 3+ , the hydrogel gradually turned its color from white to red.…”

纳米粒子薄膜热电子发射性能

“…纳米结构薄膜是由颗粒尺寸为小于 100 nm 的粒子为主体形成的薄膜. 纳米材料的发射特 性研究, 已成为国际研究领域的一个热点 [21,22] . 我们对纳米粒子所组成薄膜的热辐射特性和发射均 匀性进行了初步的研究 [23,24] , 发现这种材料具有非常强的热辐射特性和很好的发射均匀性.…”

A Universal Coating Strategy for Controllable Functionalized Polymer Surfaces

“…Due to the nature of DOPA‐induced physical adhesion of polymers on surfaces, DOPA‐based polymer coatings often have weak surface adhesion as evidenced by weak adhesion energy of 100 kJ mol −1 . [ 18 ] Even small external environmental changes (e.g., ultrasound, acid solution) can cause DOPA‐based coatings to be fall off from the surfaces. Another roadblocker is that both chemical and physical coating strategies usually lack the ability of on‐demand bonding and debonding in a reversible way.…”