Adsorption Mechanism of Cu-Doped SnO 2

The content of hydrogen is a key quantity in condition assessment and fault diagnosis of power transformer. Based on the density functional theory (DFT), the adsorption mechanism of Cu-doped SnO2 surface toward H2 has been systematically studied in this work. Firstly, the relaxation, the bond length, and overlap population of both the pure and Cu-doped SnO2 are computed. To determine the optimal doping position, the formation energies of four potential sites (i.e., Sn5c, Sn6c, Sn5c-s, and Sn6c-s) are then compared with each other. The adsorption energy and the electronic structure of SnO2 surface are analysed and discussed in detail. Furthermore, to estimate the partial atomic charges and the electrical conductance, the Mulliken population analysis is also performed. It has been found that the bridge oxygen is the most favourable position. The partial density of states of H2 after adsorption is broadened and shifted close to the Fermi level. A large amount of charges would be transferred and then released back into its conduction band, leading to the reduction of resistance and the enhancement of sensitivity toward H2. The results of this work provide references for SnO2-based sensor design

Preparation Method of Similar Materials for the Progressive Disintegration of Red-Bedded Soft Rock Based on Diagenesis Simulation

Solid waste formed during the excavation of soft red stratum rock is often encountered in engineering practice. However, its reuse has been limited because it often shows a gradual degradation mechanism during water–rock interactions. Similarity simulation experiments of geotechnical materials have been developed to be environmentally friendly; however, their application in soft rock mechanics is still limited. Based on these limitations, this study aims to prepare red-bedded soft rock-like materials by referring to the diagenetic process of sedimentary rocks using low-melting-point glass powder (STGP) and high-temperature and vertical stress to accurately simulate the progressive disintegration properties of red-bedded soft rock. For this purpose, a series of laboratory tests were conducted to verify the function of STGP in the embedment of skeleton particles of soft rock as a cement material for resisting the dry–wet cycle. Micro-scanning electron microscopy, disintegration experiments with dry–wet cycles, and basic physical and mechanical property tests were conducted for the synthetic red soft rock-like material. Finally, the synthetic and natural materials were compared based on their density, microstructure, disintegration breakage, and uniaxial compression mechanical properties. The results showed that adding STGP promoted embedded solidification between aggregate particles. The simulated material exhibited the same characteristics of gradual disintegration breakage as natural red-bedded soft rock. Meanwhile, the basic physical and mechanical properties were in substantial agreement when the STGP content was 0.5~2%

Dissociation of regional activity in default mode network in medication-naive, first-episode somatization disorder.

BACKGROUND: Patients with somatization disorder (SD) have altered neural activity in the brain regions of the default mode network (DMN). However, the regional alteration of the DMN in SD remains unknown. The present study was designed to investigate the regional alterations of the DMN in patients with SD at rest. METHODS: Twenty-five first-episode, medication-naive patients with SD and 28 age-, sex-, education- matched healthy controls underwent a resting-state functional magnetic resonance imaging (fMRI) scan. The fractional amplitude of low-frequency fluctuations (fALFF) was applied to analyze the data. RESULTS: Patients with SD showed a dissociation pattern of resting-state fALFF in the DMN, with increased fALFF in the bilateral superior medial prefrontal cortex (MPFC, BA8, 9) and decreased fALFF in the left precuneus (PCu, BA7). Furthermore, significantly positive correlation was observed between the z values of the voxels within the bilateral superior MPFC and somatization subscale scores of the Symptom Check List (SCL-90) in patients with SD. CONCLUSIONS: Our findings indicate that there is a dissociation pattern of the anterior and posterior DMN in first-episode, treatment-naive patients with SD. The results provide new insight for the importance of the DMN in the pathophysiology of SD

Regions showing fALFF differences between groups.

<p>x, y, z, coordinates of primary peak locations in the MNI space; <i>t</i> statistical value of peak voxel showing fALFF differences between the patients with SD and the controls. SD: somatization disorder.</p

The DMN mask produced in our previous studies.

<p>DMN = default mode network.</p

Voxel-wise correlation between the MPFC and the somatization subscale scores of SCL-90 in the patients.

<p>Sagittal view of the voxel-wise correlation analysis between z values of the voxels within the the bilateral superior MPFC (Montreal Neurological Institute coordinates: x = −4, y = 42, z = 52) and the somatization subscale scores of SCL-90 in the patient group at 0.05 significance level (combined height threshold <i>p</i><0.01 and a minimum cluster size = 52). MPFC = medial prefrontal cortex; somatization subscale of SCL-90 = somatization subscale of the Symptom Check List.</p

fALFF differences between the patients with SD and the controls.

<p>Red and blue denote higher and lower fALFF respectively and the color bars represent the <i>t</i> value of the group analysis. fALFF = fractional amplitudes of low-frequency fluctuations; SD = somatization disorder.</p

Regions showing fALFF differences between groups.

<p>x, y, z, coordinates of primary peak locations in the MNI space; <i>t</i> statistical value of peak voxel showing fALFF differences between the patients with SD and the controls. SD: somatization disorder.</p