瞬变电磁测深技术在构造含水体探测中的应用

构造含水体的超前探测是确保煤矿安全开采的主要因素之一。介绍了瞬变电磁法的基本原理及其方法，探讨了瞬变电磁测深技术在构造含水体探测中的应用实践，通过对瞬变电磁法探测含水体能力进行理论研究。得出用瞬变电磁法探测含水体的可行性结论。     

ω_o phase precipitation in annealed high Nb containing TiAl alloys

The ordered ω phases in high Nb containing Ti Al(Nb-Ti Al) alloys have been garnering increasing attention in the recent years. However, the investigations on the Nb dependence on the ωoprecipitation are scarce. In this study, the effect of Nb content on the ωoprecipitation in high Nb(6–10 at%) containing Ti Al alloys after long-time annealing at 850 1C has been studied. The results show that small ordered ω particles in the retained βophase cannot be discerned under scanning electron microscope(SEM) but can be observed using transmission electron microscopy(TEM). Although the Nb segregation can be eliminated after the homogenization heat treatment, the ωophase precipitated in all the alloys studied after annealing at 850 1C. TEM examination reveals that the orientation relationship between the ωoand α2phases can be derived as: [0001]ωo//[1120]α2;(1120)ωo//(0001)α2, which indicates that the ωophase is directly transformed from the parent α2phase. Small γ particles are also observed within the ωoareas. The α2-ωot γ decomposition process is expected during annealing. It is concluded that ωophase is an equilibrium phase in high Nb-Ti Al alloys at 850 1C.     

复合电镀包埋法制备纳米颗粒材料透射电镜试样

提出了一种方便实用的制备较大纳米颗粒材料透射电子显微镜(TEM)试样的方法.系统研究了电流密度和电镀时间对复合镀层的影响.通过TEM对该法制得的试样进行观察,可以得到清晰的高分辨透射电子显微像.结果表明,实验所用的钛酸锶钡纳米颗粒的生长机理是由无定形物向晶体转变的过程.运用复合电镀工艺制备TEM试样为较大的纳米材料的TEM表征提供了有效的途径.     

Porous bismuth nanocrystals with advanced sodium ion storage property

Bismuth-based materials are ideal electrodes for sodium-ion batteries(SIBs) due to their high capacity and low cost. However, conventional solid bismuth materials still suffer from severe volume expansion during the reaction process, which hinders its application. Herein, single-crystal bismuth nanospheres with diameters in the range of200–400 nm were successfully prepared with the Na–Bi alloying mechanism studied using in-situ XRD, which confirms a stepwise process of Bi→NaBi→Na3Bi with large v...     

动表生硅藻的中国新记录种——弱小楔菱藻

本研究报道了采自黄海的一个中国硅藻新记录种——弱小楔菱藻Gomphonitzschia exigua Sovereign,该藻为生活在隆背体壮蟹Romaleon gibbosulum De Haan上的动表生硅藻(Epizoic Diatom).利用透射电子显微镜对弱小楔菱藻的形态进行了详细的观察和描述,并描述了该种的...