Study on the Formation Mechanism of a Core-Shell Structure during Graphitization of Anthracite.

Graphite is a revolutionary material, and the development of synthetic graphite could potentially solve the shortage of natural graphite in the future. In this paper, the formation of core-shell-structured synthetic graphite prepared from an anthracite-FeO mixture was systematically investigated by a two-step method. First, heat treatment was performed on a layer of almandine (3FeO·Al2O3·3SiO2) particles to obtain a large quantity of uniform-sized glass-phase spheroids. Second, the deashed anthracite was graphitized on the surface of the obtained spheroids to prepare core-shell-structured graphite. Furthermore, the obtained graphite products were systematically characterized by XRD, Raman spectroscopy, SEM-EDS, and TEM. Finally, a model was proposed to illustrate the formation mechanism of the core-shell structure during graphitization of the anthracite-almandine mixture. Under lower temperatures, almandine started to melt into spheroids. Under higher temperatures, the volatile components in the anthracite turned into the gas phase, and the carbon matrix started to bend on the surface of the core material and deposit layer by layer, thus forming the core-shell-structured graphite. The findings could provide theoretical guidance for the synthetic graphite industry and have meaningful implications for the coal chemistry field.

Design of a novel gamma camera with large field of view for 16N diagnosis in the primary loop of nuclear reactor.

The assessment of the concentration and distribution of l6N, derived from 16O in the cooling water exposed to neutron irradiation, is essential for ensuring radiation safety during nuclear reactor operation. The imaging method allows for the visualization of the intensity distribution of these l6N by capturing gamma-rays emitted during their decay process. However, the existing gamma camera is exclusively compatible with gamma-rays below 2 MeV. In this paper, a novel gamma camera featuring a thick double-conical penumbra aperture, a pixelated Lu1.8Y0.2SiO5:Ce scintillator array, and a position-sensitive photomultiplier tube is proposed to address this limitation. This innovative design offers a large field of view (FOV) and is suitable for high energy extended gamma source imaging. The optimization of key parameters of the camera was conducted, and a FOV of 60° and an angular resolution of up to 4.57° were achieved. Imaging simulations, including a simplified model of the primary loop of the pressurized-water reactor by GEANT4 code and image reconstruction using the expectation maximum algorithm, demonstrated that the proposed gamma camera could obtain a satisfactory spatial resolution for diagnosing the distribution of 16N in the primary loop of a nuclear reactor.

Efficient energy transport throughout conical implosions.

The double-cone ignition (DCI) scheme has been proposed as one of the alternative approaches to inertial confinement fusion, based on direct-drive and fast-ignition, in order to reduce the requirement for the driver energy. To evaluate the conical implosion energetics from the laser beams to the plasma flows, a series of experiments have been systematically conducted. The results indicate that 89%-96% of the laser energy was absorbed by the target, with moderate stimulated Raman scatterings. Here 2%-6% of the laser energy was coupled into the plasma jets ejected from the cone tips, which was mainly restricted by the mass reductions during the implosions inside the cones. The supersonic dense jets with a Mach number of 4 were obtained, which is favorable for forming a high-density, nondegenerated plasma core after the head-on collisions. These findings show encouraging results in terms of energy transport of the conical implosions in the DCI scheme.

Development of a self-help cognitive behavioral therapy programme for reducing the stigma of stroke survivors: a modified delphi study.

BACKGROUND: Stigma is a common psychological consequence for stroke survivors that aggravates their physical and psychological burden and hinders their rehabilitation. Currently, there are few interventions targeted at the stigma of stroke survivors. OBJECTIVES: This study reports on the development of a self-help cognitive behavioral therapy (CBT) programme driven by a logical model of stigma in stroke survivors, CBT and the advice of multidomain experts. METHODS: A logical model of stigma in stroke survivors was derived from a systematic search of the literature and semistructured interviews with 21 patients to identify factors influencing stigma. The item content of the programme was generated based on this logical model in combination with CBT. A modified Delphi process with an expert panel of multidomain experts was used to evaluate and refine the content of the programme. SPSS 20.0 was used for data analysis. RESULTS: Seventeen experts accepted the invitation to participate, and all completed two rounds of the Delphi survey. Six sections and 26 items were identified. Consensus was reached among experts that the self-help CBT programme included the following six sections: health education, understanding stigma, cognition change, skills training and self-care, self-acceptance and relapse prevention. CONCLUSIONS: The self-help CBT programme includes health education and psychological education. This study extends the limited body of research on stroke-related stigma interventions, and the next step is to evaluate its efficacy in trials.

Two-dimensional monitoring of a laser-solid x-ray source spot via penumbral coded aperture imaging technique.

The uncertainties of spot size and position need to be clarified for x-ray sources as they can affect the detecting precision of the x-ray probe beam in applications such as radiography. In particular, for laser-driven x-ray sources, they would be more significant as they influence the inevitable fluctuation of the driving laser pulses. Here, we have employed the penumberal coded aperture imaging technique to diagnose the two-dimensional spatial distribution of an x-ray emission source spot generated from a Cu solid target irradiated by an intense laser pulse. Taking advantage of the high detection efficiency and high spatial resolution of this technique, the x-ray source spot is characterized with a relative error of ∼5% in the full width at half maximum of the intensity profile in a single-shot mode for general laser parameters, which makes it possible to reveal the information of the unfixed spot size and position precisely. Our results show the necessity and feasibility of monitoring the spot of these novel laser-driven x-ray sources via the penumbral coded aperture imaging technique.

The Stroke Stigma Scale: a reliable and valid stigma measure in patients with stroke.

OBJECTIVE: The objective of the study is to analyse the psychometric properties of the Stroke Stigma Scale, a novel scale to assess perceived stigma of patients with stroke. DESIGN: This is a psychometric study. SETTING: Neurology or rehabilitation units in three hospitals in China. SUBJECTS: A total of 288 patients with stroke. INTERVENTIONS: None. MEASURES: The content validity of the Stroke Stigma Scale was assessed through expert consultation. Criterion validity was evaluated based on the scale's relationships with the Stigma Scale for Chronic Illness and the Self-rating Depression Scale. Construct validity was assessed using exploratory factor analysis, and internal consistency was tested with Cronbach's α. RESULTS: The final version Stroke Stigma Scale consists of 16 items. It showed strong positive correlations with both the Stigma Scale for Chronic Illness (ρ = 0.89, P < 0.001) and the Self-rating Depression Scale (ρ = 0.82, P < 0.001). The exploratory factor analysis revealed four components of the Stroke Stigma Scale: internalized stigma, physical impairment, discrimination experience, and social isolation, which were strongly associated with our perceived stroke stigma model. Cronbach's α for the total scale was 0.92, and that of each subscale was 0.77-0.86. The test-retest reliability with intra-class correlation coefficients of the total scale was 0.92 (P < 0.001), and intra-class correlation coefficients of each subscale were 0.74-0.89 (P < 0.001). CONCLUSIONS: The Stroke Stigma Scale is a reliable and valid measure of perceived stigma in patients with stroke, which may be useful in stigma prevention and stroke rehabilitation.

Separation of the cathode materials from the Al foil in spent lithium-ion batteries by cryogenic grinding.

An environmentally friendly technology of cryogenic grinding for recovering cathode materials from spent lithium-ion batteries was has been investigated in this paper. Differential Scanning Calorimeter was used to test the glass transition temperature of the organic binder. Advanced analysis techniques, a microcomputer-controlled electronic universal material-testing machine, a low-temperature impact testing machine, scanning electron microscopy and high-resolution 3 Dimension-X-ray microscopy, were utilized to analyze the effect of low temperature on the mechanical properties and morphology of cathode. Results show that the yield strength, tensile strength and impact strength of the current collector is significantly increased at low temperature, that the glass transition temperature of the organic binder is approximately 235 K. Low temperature enhances the strength of the current collector and causes the organic binder to fail. Therefore, cryogenic grinding could realize the selective grinding of the cathode and significantly improve the peel-off of the electrode materials. The peel-off efficiency of cathode materials was improved from 25.03% to 87.29% at the optimum conditions of low temperature pretreatment for 5 min and cryogenic grinding for 30 s. The experiments demonstrate that the cryogenic grinding can obviously facilitate the efficient recovery of cathode materials, revealing a great application prospective for the recycling of spent lithium-ion batteries.

Stigma experienced by Chinese patients with stroke during inpatient rehabilitation and its correlated factors: a cross-sectional study.

Background: Stroke-related stigma can have a negative effect on patients, and is associated with stereotyping, prejudice, and discrimination; however, the exact stigma experienced by patients remains ambiguous. Objectives: To evaluate the stigma experienced by patients with stroke, determine associated factors, and explore relationships between stigma and early rehabilitation. Methods: Overall, we examined 288 patients with stroke. Patient characteristics were determined through medical records and investigations, while stigma status (comprising total stigma, internalized stigma, and enacted stigma), depression level, functional independence, and functional outcome were also assessed. Demographic and clinical characteristics were evaluated through univariate analysis, and significant variables were further analyzed through linear regression. The relationships between stigma and early rehabilitation (depression, functional independence, and functional outcomes) were also analyzed. Results: The sample's total stigma, internalized stigma, and enacted stigma scores were 47.76 ± 18.00, 30.07 ± 12.25, and 17.69 ± 6.37, respectively. Employment status before stroke, caregivers, physical impairment, and number of impairments were all relevant to all types of stigma (P< .05). The regression analysis showed that caregivers and physical impairment are the two main predictors of total, internalized, and enacted stigma (P< .01). The correlation analysis revealed that stigma is associated with depression (r = 0.671 ~ 0.690, P< .001), functional independence (r = -0.562~-0.707, P< .001), and functional outcomes (r = 0.436 ~ 0.637, P< .001). Conclusions: Stigma was moderate, and internalized stigma may be more apparent; therefore, physicians should pay more attention to patients who report or show signs of experiencing stroke-related stigma.

The preparation of synthetic graphite materials with hierarchical pores from lignite by one-step impregnation and their characterization as dye absorbents.

Herein, synthetic graphite materials with hierarchical pores and large specific surface area were successfully prepared by one-step impregnation with lignite as the carbon source, sulfuric acid (H2SO4) as the oxidant, and phosphoric acid (H3PO4) as the activator. The microstructural characteristics of synthetic graphite were investigated via X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Moreover, the pore parameters were studied by nitrogen adsorption-desorption. The results showed that synthetic graphite had a perfect orderly layered structure with high graphitization degree and a well-developed multistage pore structure with pore sizes ranging from nanometer to micrometer. The specific surface area and pore volume were 415.29 m2 g-1 and 0.67 cm3 g-1, respectively. The results of Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed that the impregnation pretreatment provided polar groups containing oxygen to the surfaces. These unique characteristics make synthetic graphite possess good adsorption capacity for dye pollutants (the adsorption rate of the methyl orange solution was 99.9% within 60 min at 50 °C, and the pH value of the solution was 3). The effects of temperature and pH value on the adsorption capacity were studied. The repeatability of the adsorption performance was also tested, and the adsorption rate was 84.6% of the initial adsorption rate after five cycles.

The role of 64-slice CT following perfusion with iohexol via the hepatopancreatic ampulla in assessing pancreaticobiliary junctions.

The aim of this study was to delineate the structure of the pancreatic and biliary ducts in premature infants using a novel imaging method. The duodenal papillae of 30 premature infant cadavers were dissected. The pancreatic and biliary ducts were visualized using 64-detector multislice spiral computed tomography (MSCT). Contrast agent was injected into the duodenal papilla via the hepatopancreatic ampulla of Vater. MSCT scanning revealed both the pancreatic and biliary ducts as well as the common channel in 18 cases. The bile duct was visualized in the remaining 12 cases. Four patterns of the pancreaticobiliary ductal junction were noted: Y-type (73.3%), U-type (13.3%), V-type (6.7%), and II-type (6.7%). The results showed that MSCT and three-dimensional reconstruction can be used to visualize the junction pattern and common channel of the pancreatic and biliary ducts, and the structure of the surrounding tissue, in premature infants.

Minimum risk facility location-allocation problem with type-2 fuzzy variables.

Facility location decision is basically viewed as a long-term strategy, so the inherited uncertainty of main parameters ought to be taken into account in order to make models applicable. In this paper, we examine the impact of uncertain transportation costs and customers' demands on the choice of optimal location decisions and allocation plans. This leads to the formulation of the facility location-allocation (FLA) problem as a fuzzy minimum risk programming, in which the uncertain parameters are assumed to be characterized by type-2 fuzzy variables with known type-2 possibility distributions. Since the inherent complexity of type-2 fuzzy FLA may be troublesome, existing methods are no longer effective in handling the proposed problems directly. We first derive the critical value formula for possibility value-at-risk reduced fuzzy variable of type-2 triangular fuzzy variable. On the basis of formula obtained, we can convert original fuzzy FLA model into its equivalent parametric mixed integer programming form, which can be solved by conventional numerical algorithms or general-purpose software. Taking use of structural characteristics of the equivalent optimization, we design a parameter decomposition method. Finally, a numerical example is presented to highlight the significance of the fuzzy FLA model. The computational results show the credibility and superiority of the proposed parametric optimization method.