Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 6 de 6
Filter
Add more filters










Database
Publication year range
1.
PeerJ Comput Sci ; 9: e1706, 2023.
Article in English | MEDLINE | ID: mdl-38077590

ABSTRACT

Alzheimer's disease (AD) is an irreversible neurodegenerative disease with a high prevalence in the elderly population over 65 years of age. Intervention in the early stages of AD is of great significance to alleviate the symptoms. Recent advances in deep learning have shown extreme advantages in computer-aided diagnosis of AD. However, most studies only focus on extracting features from slices in specific directions or whole brain images, ignoring the complementarity between features from different angles. To overcome the above problem, attention-based multi-view slice fusion (AMSF) is proposed for accurate early diagnosis of AD. It adopts the fusion of three-dimensional (3D) global features with multi-view 2D slice features by using an attention mechanism to guide the fusion of slice features for each view, to generate a comprehensive representation of the MRI images for classification. The experiments on the public dataset demonstrate that AMSF achieves 94.3% accuracy with 1.6-7.1% higher than other previous promising methods. It indicates that the better solution for AD early diagnosis depends not only on the large scale of the dataset but also on the organic combination of feature construction strategy and deep neural networks.

2.
ACS Appl Mater Interfaces ; 15(48): 56442-56453, 2023 Dec 06.
Article in English | MEDLINE | ID: mdl-37975864

ABSTRACT

The combustion efficiency of Al plays a critical role in the combustion of high-energy aluminum-based solid propellants. For traditional formulations, the Al powders are dispersed in the binder matrix, leading to limited contact with the oxidizers and hence usually insufficient combustion and higher values of the pressure exponent. In this paper, various core-shell structural Al/oxidizer composites such as Al@HMX, Al@AP, and AP@Al have been prepared by a spray-drying technique based on which solid propellants with precise interfacial control between Al particles and oxidizers were realized. Compared to the control sample, the modified propellants have a greater heat of explosion of 5890 J g-1 (15% higher) and a reduced ignition delay time of 58 ms (65% decrease). Without changing the content of components, the burn rates of propellants can be easily modulated by tuning the interfacial contact of Al and oxidizers, where it varies in a wide range of 4.56-5.79 mm s-1 at the same pressure of 1 MPa. After introducing Al/oxidizer composites, the lowest pressure exponent of 0.19 within 1-15 MPa could be achieved by using Al@HMX and AP@Al composites. The agglomeration of Al was also inhibited by using Al/oxidizer composites, and the mechanism can be interpreted by using a classical "pocket" model. Moreover, the improved combustion efficiency of the solid propellants was verified by a noticeable reduction in the unreacted Al content.

3.
Langmuir ; 39(21): 7503-7513, 2023 May 30.
Article in English | MEDLINE | ID: mdl-37186958

ABSTRACT

In this paper, the two-dimensional (2D) high nitrogen triaminoguanidine-glyoxal polymer (TAGP) has been used to dope hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) crystals using a microfluidic crystallization method. A series of constraint TAGP-doped RDX crystals using a microfluidic mixer (so-called controlled qy-RDX) with higher bulk density and better thermal stability have been obtained as a result of the granulometric gradation. The crystal structure and thermal reactivity properties of qy-RDX are largely affected by the mixing speed of the solvent and antisolvent. In particular, the bulk density of qy-RDX could be slightly changed in the range from 1.78 to 1.85 g cm-3 as a result of varied mixing states. The obtained qy-RDX crystals have better thermal stability than pristine RDX, showing a higher exothermic peak temperature and an endothermic peak temperature with a higher heat release. Ea for thermal decomposition of controlled qy-RDX is 105.3 kJ mol-1, which is 20 kJ mol-1 lower than that of pure RDX. The controlled qy-RDX samples with lower Ea followed the random 2D nucleation and nucleus growth (A2) model, whereas controlled qy-RDX with higher Ea (122.8 and 122.7 kJ mol-1) following some complex model between A2 and the random chain scission (L2) model.

4.
J Hazard Mater ; 398: 122842, 2020 Nov 05.
Article in English | MEDLINE | ID: mdl-32768811

ABSTRACT

In this paper, the widely used energetic material RDX had been modified with 2D high nitrogen polymer (TAGP). Various hybrid RDX crystals (qy-RDX) with higher detonation velocity and better thermostability had been obtained as a result of strong intermolecular interactions between TAGP and RDX molecules. The performance of the qy-RDX had been characterized to clarify the inherent mechanisms. It shows that the⊿Hf of qy-RDX could be largely changed in the range of 23.4 kJ kg-1 to 1343.6 kJ kg-1, whereas the density varies only from 1.81 g cm-3 to 1.86 g cm-3. The resulted detonation velocities are in the range of 8725.5 m·s-1 to 9251.8 m·s-1, depending on the content and state of the TAGP dopant. The sensitivity of the resulted qy-RDX is much better than pristine RDX due to improved crystal quality as well as higher concentration of hydrogen bonds. The impact energy is improved from 8.5 J (RDX) to 22 J (qy-RDX-1), whereas the friction sensitivity improves form 130 N to over 360 N for the same case. The Ea for thermal decomposition of qy-RDX-1has reduced from 147.8 kJ mol-1 (RDX) to (124.5 kJ mol-1), since TAGP dopant could be considered as active catalytic sites after melting of RDX.

5.
Appl Radiat Isot ; 69(6): 858-61, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21353786

ABSTRACT

Two thin-film (10)B samples on tantalum backings were made for measurement of cross sections of the (10)B(n,α)(7)Li reaction in the MeV neutron energy region. The number of (10)B atoms in the samples was determined using the relative comparison method by detecting alpha and triton particles from thermal neutron induced nuclear reactions of (10)B(n(th),α)(7)Li and (6)Li(n(th),t)(4)He with a (6)LiF sample as the reference. A twin gridded ionization chamber was used as the detector of charged particles.


Subject(s)
Alpha Particles , Boron/chemistry , Lithium/chemistry , Radioisotopes/chemistry , Radiometry/methods , Helium/chemistry , Isotopes , Neutrons
SELECTION OF CITATIONS
SEARCH DETAIL
...