Broad-Temperature Thermoelectric Figure of Merit Enhancement in Unconventional n-Type Bi2Te2.3Se0.7 Alloys.

Bi2Te2.7Se0.3-based alloys are conventional n-type thermoelectric materials for solid-state cooling and heat harvest near room temperature; high thermoelectric performance over a wide temperature range and superior mechanical properties are essential for their use in practical thermoelectric devices. In this work, we demonstrated that decent thermoelectric performance can also be realized in an unconventional composite with a nominal composition of Bi2Te2.3Se0.7 since the emergence of a Bi2Te2Se phase with Se ordered occupation could induce an enlargement of the electronic band gap. Follow-up Cu/Na codoping could generate a dynamic optimization of carrier concentration, significantly broadening the temperature range of high thermoelectric performance. Further B incorporation and annealing treatment resulted in obvious grain refinement and stacking fault structures, which help pushing the ultimate maximal figure of merit up to ∼1.3 at 423 K with an average value of ∼1.2 at 300-573 K. This work might provide insights for further research on bismuth tellurides and other thermoelectric materials.

Thermoelectric Cooling-Oriented Large Power Factor Realized in N-Type Bi2Te3 Via Deformation Potential Modulation and Giant Deformation.

Thermoelectric refrigeration, utilizing Peltier effect, has great potential in all-solid-state active cooling field near room temperature. The performance of a thermoelectric cooling device is highly determined by the power factor of consisting materials besides the figure of merit. In this work, it is demonstrated that successive addition of Cu and Nd can realize non-trivial modulation of deformation potential in n-type room temperature thermoelectric material Bi2Te2.7Se0.3 and result in a significant increment of electron mobility and remarkably enhanced power factor. Following giant hot deformation process improves grain texturing and strengthens inter-layer interaction in Bi2Te2.7Se0.3 lattice, further pushing the power factor to ≈47 µW cm-1 K-2 at 300 K and maximal figure of merit ZTmax to ≈1.34 at 423 K with average ZTave of ≈1.27 at 300-473 K. Moreover, robust compressive strength is enhanced to ≈146.6 MPa. The corresponding finite element simulations demonstrate large temperature differences ΔT of ≈70 K and a maximal coefficient of performance COP ≈ 10.6 (hot end temperature at 300 K), which can be achieved in a ten-pair thermoelectric cooling virtual module. The strategies and results as shown in this work can further advance the application of n-type Bi2Te3 for thermoelectric cooling.

Comparative evaluation of imaging methods for prognosis assessment in esophageal squamous cell carcinoma: focus on diffusion-weighted magnetic resonance imaging, computed tomography and esophagography.

Objective: To identify the most sensitive imaging examination method to evaluate the prognosis of esophageal squamous cell carcinoma (ESCC). Materials and methods: Thirty patients with esophageal squamous cell carcinoma (ESCC) participated in the study and underwent chemoradiotherapy (CRT). They were divided into two groups based on their survival status: the survival group and non-survival group. The diagnostic tests were utilized to determine the most effective imaging examination method for assessing the prognosis. Results: 1. There were no significant differences in tumor length shown on esophagography or computed tomography (CT) or the maximal esophageal wall thickness shown on CT at the specified time points between the two groups. 2. The tumor length on diffusion-weighted imaging (DWI) in the survival group was significantly lower than in the non-survival group at the end of the sixth week of treatment (P=0.001). The area under the ROC curve was 0.840 (P=0.002), and the diagnostic efficiency was moderately accurate. 3. The apparent diffusion coefficient (ADC) values of the survival group were significantly higher than those in the non-survival group at the end of the fourth week and sixth week of treatment (both P<0.001). Areas under the curve were 0.866 and 0.970, with P values of 0.001 and <0.001 and good diagnostic accuracy. Cox regression analyses indicated the ADC at the end of the sixth week of treatment was an independent risk factor. Conclusions: Compared with esophagography and CT, DW-MRI has certain advantages in predicting the prognosis of ESCC.

Modified lignin can achieve mitigation of ammonia and greenhouse gas emissions simultaneously in composting.

The constant ammonia gas (NH3) and greenhouse gases (GHG) emissions were considered as a deep-rooted problem in composting which caused air pollution and global climate change. To achieve the mitigation of NH3 and GHG, a novel additive derived from wasted straw, with modified structure and functional groups, has been developed. Results showed that the adsorption capacity of modified lignin (ML) for both ammonium and nitrate was significantly increased by 132.5-360.8 % and 313.7-454.3 % comparing with biochar (BC) and phosphogypsum (PG) after reconstructing porous structure and grafting R-COOH, R-SO3H functional groups. The application of ML could reduce 36.3 % NH3 emission during composting compared with control. Furthermore, the synergetic mitigation NH3 and GHG in ML treatment resulted in a reduction of global warming potential (GWP) by 31.0-64.6 % compared with BC and PG. These findings provide evidence that ML can be a feasible strategy to effectively alleviate NH3 and GHG emissions in composting.

Synthesis of a slow-release fertilizer composite derived from waste straw that improves water retention and agricultural yield.

To enhance waste straw utilization and improve fertilizer efficiency, a novel semi-interpenetrating polymer network fertilizer (CMCK-g-PAA/PDMUP) was prepared from straw cellulose and linear polymer by solution polymerization. Polydihydroxymethyl-urea potassium phosphate (PDMUP) was included to supply nitrogen, phosphorus, and potassium nutrients. Characterization of CMCK-g-PAA/PDMUP with FTIR, XPS, XRD, and SEM techniques provided evidence for semi-interpenetrating polymer networks (semi-IPNs) and component interactions. The prepared product exhibited excellent water absorbency (681.3 g/g) and enhanced the soil's water-retention capacity. Cumulative release of N, P, and K was 56.1%, 64.3%, and 74.1%, respectively, after 40 days-meeting a Committee of European Normalization (CEN) standard. Agricultural application of CMCK-g-PAA/PDMUP promoted wheat growth. Desirable water retention, slow-release properties, and wheat growth effects highlight the product's potential for improving agriculture.