Phase transitions, micro-morphology and its oxidation mechanism in oxidation of ilmenite (FeTiO_3) powder

Phase transitions, morphology changes, and oxidation mechanism of the ilmenite oxidation process were investigated. FeTi03 transforms to hematite and rutile when oxidation at 700-800 ℃, and pseudobrookite is formed when the oxidation temperature reaches 900 ℃. The initial ilmenite powder exhibits paramagnetism; however, after being oxidized at the intermediate temperature （800-850 ℃）, the oxidation product exhibits weak ferromagnetism. The oxidation mechanism was discussed. The microstructure observations show that a lot of micro-pores emerge on the surfaces of ilmenite particles at the intermediate temperature, which is deemed to be caoable ofenhancin~ the mass transfer ofoxgen during oxidation.

Oxidation roasting of molybdenite concentrate

In order to investigate the oxidation roasting of molybdenite concentrate in pure oxygen atmosphere, experiments at 673, 723, 773, 873 and 973 K were carried out. The phase transitions and morphology evolutions of the samples obtained at different temperatures after reacting for different time were analyzed by X-ray diffraction（XRD） and scanning electron microscopy（SEM）. The results showed that molybdenite concentrate was oxidized directly to Mo O3 in pure oxygen atmosphere. There were remarkable changes of the morphologies of products with the increase of the roasting temperature. It was also found that sintering phenomenon occurred during the roasting process in pure oxygen when the temperature was above 873 K. The composition of sintered sample was mainly comprised of Mo O3 and some unreacted Mo S2.

Microbially induced deposition of barium phosphates and its ingredient,morphology and size under different pH values

A phosphate-mineralization microbe was used to induce barium phosphates precipitation, and the precipitates with different types were obtained under different pH values. The average crystallite size of the barium phosphates was calculated by particle size distribution curves, and the size of the products was 33.40, 29. 37, 24. 13, 47.76 and 96. 53 μm when the pH values of the mixed solution are 7, 8, 9, 10 and 11, respectively. The results of X-ray diffraction （XRD） show that the structures of the particles controlled by the mixed solution are mainly BaaPO4 when pH 〈 10; the barium phosphates are synthesized by biological deposition which is the mixture of BaHPO4 and Ba5 （PO4）3OH when pH = 10; when pH = 11, the barium phosphates are also the mixtures, which are Ba5 （PO4）3OH and BaNaPO4. The above results indicate that the phosphate-mineralization microbe can produce a certain enzyme which constantly hydrolyzes phosphate monoester in the mixed solution, and then PO4^3- ions are obtained.

Macroscopic and microscopic fracture features of concrete used in coal mine under chlorine salt erosion

The microscopic morphology and pore structure characteristics of concrete with composite admixtures(fly ash and mineral powder) after chlorine salt erosion were analyzed via scanning electron microscopy(SEM) and mercury injection porosimetry(MIP), providing the basis for the design and maintenance of concrete shafts in coal mines. The above-mentioned characteristics were compared with the macroscopic characteristic of concrete fractures under uniaxial compression. The results show that the macroscopic fracture characteristics of concrete under uniaxial compression change from longitudinal split fracture and oblique section shear fracture to conjugate cant fracture, and the degree of breakage increases.Interface cracks, cement paste cracks, spherical surface cracks, and aggregate cracks appear in concrete under uniaxial compression. In the early stages of corrosion, the original cracks which are obvious are repaired. When the corrosion becomes more serious, cement paste cracks appear, and the number of harmful holes increases while the number of harmless holes decreases. This study also reveals the relationship between the macroscopic properties and microscopic structure of concrete under chloride salt erosion. Finally, the paper preliminarily discussed the relationship between the macroscopic properties and mesoscopic characteristics of concrete under chlorine salt erosion.

红一矿创建文明矿区侧记

今年,龙岩矿务局红一矿在抓好经济建设的同时,注重加大对精神文明建设的投入。该矿从改造矿容矿貌、创建温暖“家庭”和加强综合治理等方面入手,大力创建矿区精神文明,使矿区的面貌发生了喜人的变化。 优美的矿容矿貌 当走近红一矿时,首先映入你眼帘的是:紫红色草铺植的“开拓奋进,振兴红一”八个大字。楼前绿草如茵,花木成行,蝉鸣啁啁。

大山的儿子——访云南田坝煤矿矿长夏跃章

今年9月我在昆明开会时,听云南煤炭厅的同志说,田坝煤矿无论是生产经管,还是矿风矿貌都遐迩闻名,中央与北京电视台曾先后在那里拍摄过《地火》和《共和国往事》大型电视片。尤其是现任矿长夏跃章是位很有个性、政绩很突出的基层干部。而在他的履历表上填写他只有初中文化,这在目前全国国内煤矿矿长里是不多见的,或许是唯一的。

两个文明建设的带头人——矿长方荣礼

面对今日蒋庄矿已取得的这些辉煌成绩,人们不会忘记这位1993年任经营矿长、1995年经民意测验、组织考评接任主管矿长的方荣礼同志,是他带领蒋庄矿人将两个文明建设又推向了一个新的历程。 靠深谋远虑,运筹帷幄,拓宽“物质路” 了解方荣礼的人都知道,他具有一种能够驾驭全局、把握主流的魄力和深思熟虑。

Kelvin probe force microscopy for perovskite solar cells

Kelvin probe force microscopy(KPFM) could identify the local work function of surface at nanoscale with high-resolution on the basis of simultaneous visualization of surface topography, which provides a unique route to in-situ study of the surface information like the composition and electronic states. Currently, as a non-destructive detection protocol, KPFM demonstrates the unique potential to probe the basic nature of perovskite materials that is extremely sensitive to water, oxygen and electron beam irradiation. This paper systematically introduces the fundamentals and working mode of KPFM, and elaborates the promising applications in perovskite solar cells for energy band structures and carrier transport dynamics, trap states, crystal phases, as well as ion migration explorations. The comprehensive understanding of such potential detection engineering may provide novel and effective approaches for unraveling the unique properties of perovskite solar cells.