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[en] The growth and morphology of cobalt nanocrystals prepared by γ-irradiation method in a homogenous solution were significantly changed when a static magnetic field was introduced. The irradiation was carried out at the dose rate of 55 Gy/min for 27 h. The phase structures of the products were characterized by the means of X-ray powder diffraction (XRD). TEM images were used to observe the morphologies and dimensions of obtained cobalt nanocrystals. Meanwhile, a possible mechanism for the formation of the cobalt nanowires was proposed from the interaction between the magnetic field and cobalt clusters which were produced during the irradiation
[en] In the present investigation, Al-12Si, Al-20Si and Al-25Si (wt%) alloys were synthesized by spray atomization and deposition technique. The wear resistance of the alloys was studied using a pin-on-disc machine under four loads, namely 8.9, 17.8, 26.7 and 35.6 N. The microstructures, worn surfaces and the debris were analyzed in a scanning electron microscope. It has been found that the effect of Si content on dry sliding wear of spray-deposited Al-Si alloy was associated with applied loads. At lower load (8.9 N), with increasing Si content, the wear rate of the alloy was decreased. At higher load (35.6 N), spray-deposited Al-20Si alloy exhibited superior wear resistance to the Al-12Si and Al-25Si alloys
[en] With the increasing of data storage and data access in EAST experiment, standardized data access and user behavior monitoring become even more important. Therefore, a perfect EAST MDSplus logging system is required, and a mature log data management system is built on this basis. The EAST MDSplus log data management system architecture includes four parts: the log data collection layer, the data storage layer, the data analysis layer and the data application layer. (1) The data collection layer uses MDSplus hook function to improve the log system, and adopts log rotate mechanism for log rotation cutting, which effectively avoids the problem of excessive log storage. (2) The data storage layer uses HDFS for distributed offline data storage to support data multi-copy backup, which improves data security performance and non-volatileness. Moreover, Kafka is also used as the stream data storage middleware to ensure the release and subscription of log messages with high throughput. (3) The data analysis layer uses MapReduce to clean the offline data and establish the log data warehouse belonging to EAST. In addition, Spark Streaming is used to calculate log stream data to ensure the quasi-real-time nature of log data. (4) The data application layer is designed to visualize analysis layer data and intuitively reflect the entire EAST log data access status. Each layer of the log management system framework provides a corresponding interface, which reduces the coupling degree of the system. The EAST MDSplus log data management system aims at providing a standardized management solution for the whole EAST log data and it will be implemented in the next campaign of EAST experiment.
[en] The luminescence behavior of the europium (Eu) complexes with hexafluoracetylacetonate (HFA:Eu3+ complexes) in the ORMOSIL matrices has been investigated. The steady-state excitation and emission spectra of the 1 mol.% EuCl3 and the 3 mol.% hexafluoracetylacetonate (HFA) co-doped gel were similar to that of the HFA:Eu3+ complexes powders which were synthesized in ethanol solution, which indicated that the HFA:Eu3+ complexes have been synthesized in the 1 mol.% EuCl3 and the 3 mol.% HFA co-doped gel. The time-resolved spectra of the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel exhibited the ligand-to-metal energy transfer process, which also confirmed the synthesis of the HFA:Eu3+ complexes in the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel. The decay curves of the luminescence 5D0 state obtained by monitoring the 5D0→7F2 emission line for the HFA:Eu3+ complexes powders and for the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel could both be fitted to a single-exponential fitting function. The temperature of heat treatment has significant influence on the luminescence behavior of the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel. The luminescence intensities of the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel reached a maximum at approximately 110 deg. C and decreased gradually with increasing temperature. However, the 5D0 excited-state lifetimes of the Eu3+ ions in the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gels increased gradually with increasing temperature
[en] The paper deals with two methods to recognition nuclear explosion electromagnetic pulse based on neutral network and fuzzy. Firstly the feature value extraction for the sample of nuclear explosion signals and lighting signals is discussed. Secondly two mathematic models are established. Finally, we test the recognition efficiency of the two method with certain amount of samples, the recognition includes the classification between nuclear explosions and lighting and the classification between hydrogen bombs and atomic bombs