Monodisperse Fe3O4 nanocubes have been successfully synthesized by a facile solvothermal method at 260 °C in the presence of oleic acid and oleylamine. Well-defined assembly of uniform Fe3O4 ...nanocubes with an average size of 12 nm could be obtained without a size-selection process. The shape of as-prepared Fe3O4 nanoparticles could be reversibly interchanged between spheres and cubes by adjusting the reaction parameters. The phase structures, morphologies, and sizes of as-prepared products were investigated in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The magnetic properties of Fe3O4 nanocubes were measured by using a quantum design superconducting quantum interference device (SQUID). The magnetic study reveals that the as-synthesized nanocubes are ferromagnetic at 2 K while they are superparamagnetic at 300 K.
Hollow metallic nickel spheres with an average diameter of 1.8 μm have been successfully synthesized via a decomposition and reduction route by using hollow nickel hydroxide spheres as precursor. ...Microsized hollow bimetallic (Ni/Au, Ni/Ag, Ni/Pt, and Ni/Pd) and noble metal (Pt and Pd) spheres have also been selectively synthesized by adjusting the amount of reactants of replacement reaction in which corresponding noble metal compound and hollow metallic nickel spheres were used as starting materials. The magnetic properties of hollow metallic nickel spheres have been investigated. It is found that the coercivity of hollow Ni spheres is much enhanced compared with their bulk counterparts. The study on catalytic activities of the as-prepared hollow noble metal spheres for hydrogen generation reveals that Ni/Pt hollow bimetallic spheres exhibit favorable catalytic activities which have potential applications in portable hydrogen generation systems.
Background
Ali CMB polarization telescope (AliCPT) project is a well-timed and well-planned ground-based CMB project in Ali (Nagri) area of Tibet, China. It has been approved at the end of 2016.
Aims
...To give an introduction to the detection technology of AliCPT.
Method
The whole receiver of AliCPT is introduced and discussed, including the optics, the cryostat, the preliminary design of focal plane TES bolometers, multiplexing SQUID readout, and so on.
Conclusions
The raw sensitivity of
r
will reach below 0.001 by 10-year observation as AliCPT project being carried out and upgraded.
Uniform chrysanthemum-like bismuth sulfide (Bi
2S
3) microcrystals assembled from nanosheet building blocks were successfully synthesized via a convenient hydrothermal synthetic route under mild ...conditions in which hydrated bismuth nitrate and
l-cysteine were employed to supply Bi and S source and ethylenediaminetetraacetic acid disodium salt (EDTA-Na
2) was employed as chelating agent. The influences of reaction temperatures and time on the morphologies of final products were investigated. The phase structures, morphologies, and properties of as-prepared products were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscope, and photoluminescence spectra. The possible growth mechanism for the formation of chrysanthemum-like Bi
2S
3 microcrystals was discussed on the basis of the experimental results.
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The use of machine learning models for productivity prediction in complex manufacturing systems has garnered significant attention. However, the implementation of conventional black-box machine ...learning models is challenging due to the complexity and limited data availability in aircraft final assembly lines. These challenges stem from a lack of explainability, leading to compromised accuracy and diminished trustworthiness. To address this issue, this paper proposes an explainable neural network model, the Attention-SP-LSTM-FIG, specifically designed for productivity prediction in aircraft final assembly lines. First, the serial-parallel LSTM is utilized to map the process sequence within each assembly station, and a customized attention mechanism maps the requirements of workers and materials. This process results in independent sub-models corresponding to each station. Subsequently, the outputs from each sub-model are combined using a specially-designed final integrated gate to produce the final output. Finally, a post-hoc analysis of the weight data in the model is performed following the backpropagation order to identify the various production bottlenecks in the assembly line. The performance of the proposed model has been evaluated through an industrial case study. In terms of accuracy, the Attention-SP-LSTM-FIG surpasses other benchmark neural network models in terms of error, correlation, and precision metrics. Regarding explainability, the Attention-SP-LSTM-FIG can precisely identify bottlenecks for practitioners, thus facilitating a better understanding of the rationale behind the model’s outputs.
As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as
Insight
-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) ...slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.
Monodisperse Zn ferrite nanospheres and its Ba substitution nanosheets were successfully prepared by a facile solvothermal method. The size, morphology, and structure of the as-prepared products were ...investigated in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Magnetic studies revealed that Zn ferrite nanospheres are ferrimagnetic with a saturation magnetization
(
M
s
)
of 49.6 emu /g and
M
s
increased from 49.6 emu /g to 84.2 emu /g when Ba
2+ was substituted into Zn ferrite to form BaZn ferrite nanosheets. To explain the variations of morphology and magnetic properties, the strong preferential occupancy of cations in chemically equivalent A and B sites and the metastable cation distribution in nanoparticles are invoked.
Monodisperse Fe3O4 nanoparticles were successfully synthesized through the thermal decomposition of iron acetylacetonate in octadecene solvent in the presence of oleic acid and oleylamine. The ...influences of experimental parameters, such as reacting temperature, amounts and kinds of surfactants, solvents, oleic acid and oleylamine, on the size and shape of monodisperse Fe3O4 nanoparticles were discussed. The phase structures, morphology, and size of the as‐prepared products were investigated in detail by X‐ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and high‐resolution transmission electron microscopy (HRTEM). Magnetic property was measured using a vibrating sample magnetometer (VSM) at room temperature, which revealed that Fe3O4 nanoparticles were of ferromagnetism with a saturation magnetization (Ms) of 74.0 emu/g and coercivity (Hc) of 72.6 Oe.
This paper successfully synthesized monodisperse Fe3O4 nanocrystals with narrow size distribution through thermal decomposition of iron acetylacetonate in octadecene solvent. Surfactants, such as TOPO, SDS, CTAB, PEG, and PVP were used to modulate the particle size and morphology.
Finding the electromagnetic （EM） counterpart of binary compact star merger, especially the binary neutron star （BNS） merger, is critically important for gravitational wave （GW） astronomy, cosmology ...and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope （HE） onboard Insight-HXMT （Hard X-ray Modulation Telescope） is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart （SSS17a/AT2017gfo） with very large collection area （M000 cm2） and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity （TOO） observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy （0.2-5 MeV） radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints （-10-7 to 104 erg/cm2/s） for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.
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