| 1. |
- Long, Jianzhan, 1979, et al.
(författare)
-
Influences of Cr contents on oxidation behavior of WC-Co-Ni-Cr cemented carbides at 900 °C
- 2024
-
Ingår i: International Journal of Refractory Metals and Hard Materials. - 0263-4368 .- 2213-3917. ; 118
-
Tidskriftsartikel (refereegranskat)abstract
- Modification of binder composition is an effective way to improve the oxidation resistance of WC-Co-Ni-Cr cemented carbide. Since the adjustment of Ni and Cr contents in the Co-Ni-Cr binder alters the oxidation behavior and oxidation products, WC-Co-Ni-Cr cemented carbide is expected to achieve excellent oxidation resistance in severe service conditions. In this paper, the influences of Cr contents in Co-Ni-Cr binder phase with a fixed total amount of Co and Ni on the oxidation behavior of WC-Co-Ni-Cr cemented carbides at 900 °C was investigated. The oxide morphology and phase distribution were focused. The oxidation mechanism of WC-Co-Ni-Cr cemented carbide was discussed. It has been shown that Co-rich regions are preferentially oxidized in the initial stage of oxidation. As oxidation proceeds (60 min), the dominant oxidation product on the alloy surface is NiO. The oxidation resistance of the WC-Co-Ni-Cr cemented carbide increases with increasing Cr content in the binder. Compared to the series of WC-2Co-11Ni-xCr, WC-6.5Co-6.5Ni-xCr presents a better overall oxidation resistance due to the formation of Cr2O5 in the middle of the oxide layer.
|
|
| 2. |
- Ren, Liqun, et al.
(författare)
-
Heterogenic Distribution of Aromatic L-Amino Acid Decarboxylase Neurons in the Rat Spinal Cord
- 2017
-
Ingår i: Frontiers in Integrative Neuroscience. - : Frontiers Media SA. - 1662-5145. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Aromatic L-amino acid decarboxylase (AADC) is an essential enzyme in the synthesis of serotonin, dopamine, and certain trace amines and is present in a variety of organs including the brain and spinal cord. It is previously reported that in mammalian spinal cord AADC cells (called D-cells) were largely confined to a region around the central canal and that they do not produce monoamines. To date, there has not been a detailed description of their distribution and morphology in mammals. In the present study this issue is systematically investigated using immunohistochemistry. We have found that AADC cells in the rat spinal cord are both more numerous and more widely distributed than previously reported. In the gray matter, AADC neurons immunolabeled for NeuN were not only found in the region around the central canal but also in the dorsal horn, intermediate zone, and ventral horn. In the white matter a large number of glial cells were AADC-immunopositive in different spinal segments and the vast majority of these cells expressed oligodendrocyte and radial glial phenotypes. Additionally, a small number of AADC neurons labeled for NeuN were found in the white matter along the ventral median fissure. The shapes and sizes of AADC neurons varied according to their location. For example, throughout cervical and lumbar segments AADC neurons in the intermediate zone and ventral horn tended to be rather large and weakly immunolabeled, whereas those in comparable regions of sacrocaudal segments were smaller and more densely immunolabeled. The diverse morphological characteristics of the AADC cells suggests that they could be further divided into several subtypes. These results indicate that AADC cells are heterogeneously distributed in the rat spinal cord and they may exert different functions in different physiological and pathological situations.
|
|
