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1.
Int Immunopharmacol ; 137: 112431, 2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38897125

ABSTRACT

Osteoarthritis (OA), a degenerative joint disorder, has an unclear immune infiltration mechanism in subchondral bone (SCB). Thus, this study aims to discern immune infiltration variations in SCB between early- and late-stages of OA and identify pertinent biomarkers. Utilizing the GSE515188 bulk-seq profile from the Gene Expression Omnibus database, we performed single-sample gene-set enrichment analysis alongside weighted gene co-expression network analysis to identify key cells and immune-related genes (IRGs) involved in SCB at both stages. At the meanwhile, differentially expressed genes (DEGs) were identified in the same dataset and intersected with IRGs to find IR-DEGs. Protein-protein interaction network and enrichment analyses and further gene filtering using LASSO regression led to the discovery of potential biomarkers, which were then validated by ROC curve analysis, single-cell RNA sequencing, qRT-PCR, western blot and immunofluorescence. ScRNA-seq analysis using GSE196678, qRT-PCR, western blot and immunofluorescence results confirmed the upregulation of their expression levels in early-stage OA SCB samples. Our comprehensive analysis revealed lymphocytes infiltration as a major feature in early OA SCB. A total of 13 IR-DEGs were identified, showing significant enrichment in T- or B-cell activation pathways. Three of them (CD247, POU2AF1, and TNFRSF13B) were selected via the LASSO regression analysis, and results from the ROC curve analyses indicated the diagnostic efficacy of these 3 genes as biomarkers. These findings may aid in investigating the mechanisms of SCB immune infiltration in OA, stratifying OA progression, and identifying relevant therapeutic targets.

2.
Article in English | MEDLINE | ID: mdl-38836956

ABSTRACT

PURPOSE: After robotic-assisted total knee arthroplasty (RA-TKA) surgery, some patients still experience joint discomfort. We aimed to establish an effective machine learning model that integrates radiomic features extracted from computed tomography (CT) scans and relevant clinical information to predict patient satisfaction three months postoperatively following RA-TKA. MATERIALS AND METHODS: After careful selection, data from 142 patients were randomly divided into a training set (n = 99) and a test set (n = 43), approximately in a 7:3 ratio. A total of 1329 radiomic features were extracted from the regions of interest delineated in CT scans. The features were standardized using normalization algorithms, and the least absolute shrinkage and selection operator regression model was employed to select radiomic features with ICC > 0.75 and P < 0.05, generating the Rad-score as feature markers. Univariate and multivariate logistic regression was then used to screen clinical information (age, body mass index, operation time, gender, surgical side, comorbidities, preoperative KSS score, preoperative range of motion (ROM), preoperative and postoperative HKA angle, preoperative and postoperative VAS score) as potential predictive factors. The satisfaction scale ≥ 20 indicates patient satisfaction. Finally, three prediction models were established, focusing on radiomic features, clinical features, and their fusion. Model performance was evaluated using Receiver Operating Characteristic curves and decision curve analysis. RESULTS: In the training set, the area under the curve (AUC) of the clinical model was 0.793 (95% CI 0.681-0.906), the radiomic model was 0.854 (95% CI 0.743-0.964), and the combined radiomic-clinical model was 0.899 (95% CI 0.804-0.995). In the test set, the AUC of the clinical model was 0.908 (95% CI 0.814-1.000), the radiomic model was 0.709 (95% CI 0.541-0.878), and the combined radiomic-clinical model was 0.928 (95% CI 0.842-1.000). The AUC of the radiomic-clinical model was significantly higher than the other two models. The decision curve analysis indicated its clinical application value. CONCLUSION: We developed a radiomic-based nomogram model using CT imaging to predict the satisfaction of RA-TKA patients at 3 months postoperatively. This model integrated clinical and radiomic features and demonstrated good predictive performance and excellent clinical application potential.

3.
Nat Commun ; 15(1): 2877, 2024 Apr 03.
Article in English | MEDLINE | ID: mdl-38570489

ABSTRACT

Growing evidence has confirmed the critical role played by basal channels beneath Antarctic ice shelves in both ice shelf stability and freshwater input to the surrounding ocean. Here we show, using a 3D ice shelf-ocean boundary current model, that deeper basal channels can lead to a significant amplification in channelized basal melting, meltwater channeling, and warming and salinization of the channel flow. All of these channelized quantities are also modulated by channel width, with the level of modulation determined by channel height. The explicit quantification of channelized basal melting and the meltwater transport in terms of channel cross-sectional shape is potentially beneficial for the evaluation of ice shelf mass balance and meltwater contribution to the nearshore oceanography. Complicated topographically controlled circulations are revealed to be responsible for the unique thermohaline structure inside deep channels. Our study emphasizes the need for improvement in observations of evolving basal channels and the hydrography inside them, as well as adjacent to the ice front where channelized meltwater emerges.

4.
ACS Appl Mater Interfaces ; 16(15): 19048-19056, 2024 Apr 17.
Article in English | MEDLINE | ID: mdl-38578807

ABSTRACT

The intrinsic low electrical properties have hindered the enhancement of thermoelectric performance for n-type PbTe over a long period of time, primarily due to the generation of intrinsic Pb vacancies and other defects. In this work, PbTe samples with nonstoichiometric excess Pb atoms were successfully prepared by a melting reaction followed by spark plasma sintering. First, the introduction of precisely controlled excess Pb atoms has effectively eliminated the typical p-n transition phenomenon in PbTe systems by suppressing the generation of Pb vacancies. Further, the vacuum annealing process employed in nonstoichiometric samples increases the carrier mobility significantly because of the improved crystallinity and the lowered holes. Thus, the Hall mobility was optimized from 754.3 to 1215.9 cm2 V-1 s-1, while the power factor was ultimately elevated from 3087.8 to 4565.7 µW m-1 K-2 for the Pb1.03Te sample at 323 K. Benefited from the enhanced electrical transport properties near room temperature, an average zT ∼ 1.03 ranging from 323 to 723 K was achieved, demonstrating an outstanding performance in n-type nondoped PbTe. This work provides guidance for optimizing the thermoelectric performance of n-type PbTe and relevant telluride by reducing vacancies and other defects.

6.
Sci Rep ; 13(1): 18919, 2023 11 02.
Article in English | MEDLINE | ID: mdl-37919317

ABSTRACT

With the aging of the population, an increasing number of elderly patients are opting for artificial joint replacement, leading to the exploration of various rapid rehabilitation programs in the perioperative period. In this study, we aimed to investigate the effectiveness of combining recombinant human erythropoietin and iron sucrose in altering the range and trend of postoperative hemoglobin in patients undergoing arthroplasty. Specifically, we will examine whether this combination can effectively alter the rise and fall of postoperative haemoglobin, identify the inflection point of haemoglobin change or recovery after arthroplasty, and assess the effect of treatment on serum iron in postoperative blood. We conducted a retrospective study of 138 patients who underwent unilateral total joint arthroplasty by the same surgeon in the same hospital before July 2022. The results of this study may provide valuable insights for the development of effective rehabilitation programs for patients undergoing arthroplasty.


Subject(s)
Arthroplasty, Replacement, Hip , Arthroplasty, Replacement , Erythropoietin , Humans , Aged , Ferric Oxide, Saccharated , Retrospective Studies , Hemoglobins/analysis , Erythropoietin/therapeutic use
7.
RSC Adv ; 13(37): 25797-25803, 2023 Aug 29.
Article in English | MEDLINE | ID: mdl-37664203

ABSTRACT

High-quality Bi2Sr2CaCu2O8+δ superconducting thin films are successfully grown on a SrTiO3 substrate by the Pulsed Laser Deposition technique. Superconducting critical transition temperatures Tc,zero have reached up to 85 K by using optimized growth parameters. In addition, we demonstrated the two-dimensional nature of the superconductivity of thin films by virtue of exhibiting Berezinskii-Kosterlitz-Thouless (BKT) physics and anisotropic magnetic response. Furthermore, three distinct regimes are identified based on the analysis of direct current resistance. The non-Fermi liquid phase and BKT phase fluctuation zone almost perfectly merge together, which implies that the system undergoes a unique topological state that is determined by the BKT phase fluctuation preceding the onset of the superconducting state. The emergence of such a topological state radically differentiates from the three-dimensional superconducting transition, which spontaneously breaks the gauge symmetry. The current studies on the Bi2Sr2CaCu2O8+δ superconducting thin films provide some new insights for understanding the rich quantum states of matter that emerge in the vicinity of the superconducting phase transition and highlight the significant role of BKT fluctuation on two-dimensional superconducting transition.

8.
Sci Adv ; 9(17): eadh0713, 2023 Apr 28.
Article in English | MEDLINE | ID: mdl-37126545

ABSTRACT

By the fine manipulation of the exceptional long-range germanium-telluride (Ge─Te) bonding through charge transfer engineering, we have achieved exceptional thermoelectric (TE) and mechanical properties in lead-free GeTe. This chemical bonding mechanism along with a semiordered zigzag nanostructure generates a notable increase of the average zT to a record value of ~1.73 in the temperature range of 323 to 773 K with ultrahigh maximum zT ~ 2.7. In addition, we significantly enhanced the Vickers microhardness numbers (Hv) to an extraordinarily high value of 247 Hv and effectively eliminated the thermal expansion fluctuation at the phase transition, which was problematic for application, by the present charge transfer engineering process and concomitant formation of microstructures. We further fabricated a single-leg TE generator and obtained a conversion efficiency of ~13.4% at the temperature difference of 463 K on a commercial instrument, which is located at the pinnacle of TE conversion.

9.
J Arthroplasty ; 38(8): 1510-1515, 2023 08.
Article in English | MEDLINE | ID: mdl-36773662

ABSTRACT

BACKGROUND: The effectiveness of 2 treatment options, screw-cement fill, and adequate osteotomy with a thick liner, in treating patients with Rand IIb tibial defects (tibial plateau defects to a depth of 5 to 10 millimeters) in primary total knee arthroplasty (TKA) has not yet been demonstrated. Therefore, we performed a retrospective study to evaluate the differences between these 2 treatments. METHODS: We retrospectively analyzed patients who underwent primary TKA for Rand IIb tibial plateau defects from 2015 to 2020 from a department database. Patients were categorized into the screw-cement and thick liner groups based on the different options used to repair tibial defects. We evaluated Knee Society Score, range of motion (ROM), Insall-Salvati index (ISI), and Forgotten Joint Score (FJS) in both groups. We also compared differences in prosthesis survival, stiffness, myasthenia, and joint clicking between the 2 groups at mean 2 years postoperatively (range, 2 to 2.3). A power analysis was performed on the number of cases in the cohort. RESULTS: Postoperative femur-tibia mechanical axis (FTMA) correction was significantly higher in the screw-cement group than in the thick-liner group: 18.8 (±5.6°) versus 15.4 (±5.9°) (P < .01); At mean 2 years after surgery, the American Knee Society Functional Score improvement values were higher in the thick-liner group than in the screw-cement group: 36.3 (±12.4) versus 42.4 (±16.4) (P = .05). Postoperative ISI scores were 0.95 (±0.12) points in the screw-cement group and 0.89 (±0.13) points in the-thick liner group (P = .03). There were no statistically significant differences in the Knee Society Clinical Score, ROM, FJS, stiffness, myasthenia, joint clicking, and revision rate. CONCLUSION: The results of this study showed no significant difference in clinical outcomes between the 2 reconstruction strategies of the screw cement fill technique and the adequate osteotomy and thick liner technique for Rand IIb tibial plateau defects. However, in patients who have FTMA deformities greater than 20° or in younger patients who need to preserve bone volume, we recommend the screw cement filling technique to ensure stable postoperative results and to prepare these patients for possible later surgery.


Subject(s)
Arthroplasty, Replacement, Knee , Knee Prosthesis , Osteoarthritis, Knee , Humans , Arthroplasty, Replacement, Knee/methods , Tibia/surgery , Knee Joint/surgery , Retrospective Studies , Bone Screws , Osteotomy/methods , Bone Cements , Osteoarthritis, Knee/surgery , Treatment Outcome
10.
J Med Internet Res ; 25: e37599, 2023 03 10.
Article in English | MEDLINE | ID: mdl-36651587

ABSTRACT

BACKGROUND: Virtual and augmented reality (VAR) represents a combination of current state-of-the-art computer and imaging technologies and has the potential to be a revolutionary technology in many surgical fields. An increasing number of investigators have developed and applied VAR in hip-related surgery with the aim of using this technology to reduce hip surgery-related complications, improve surgical success rates, and reduce surgical risks. These technologies are beginning to be widely used in hip-related preoperative operation simulation and training, intraoperative navigation tools in the operating room, and postoperative rehabilitation. OBJECTIVE: With the aim of reviewing the current status of virtual reality (VR) and augmented reality (AR) in hip-related surgery and summarizing its benefits, we discussed and briefly described the applicability, advantages, limitations, and future perspectives of VR and AR techniques in hip-related surgery, such as preoperative operation simulation and training; explored the possible future applications of AR in the operating room; and discussed the bright prospects of VR and AR technologies in postoperative rehabilitation after hip surgery. METHODS: We searched the PubMed and Web of Science databases using the following key search terms: ("virtual reality" OR "augmented reality") AND ("pelvis" OR "hip"). The literature on basic and clinical research related to the aforementioned key search terms, that is, studies evaluating the key factors, challenges, or problems of using of VAR technology in hip-related surgery, was collected. RESULTS: A total of 40 studies and reports were included and classified into the following categories: total hip arthroplasty, hip resurfacing, femoral neck fracture, pelvic fracture, acetabular fracture, tumor, arthroscopy, and postoperative rehabilitation. Quality assessment could be performed in 30 studies. Among the clinical studies, there were 16 case series with an average score of 89 out of 100 points (89%) and 1 case report that scored 81 (SD 10.11) out of 100 points (81%) according to the Joanna Briggs Institute Critical Appraisal Checklist. Two cadaveric studies scored 85 of 100 points (85%) and 92 of 100 points (92%) according to the Quality Appraisal for Cadaveric Studies scale. CONCLUSIONS: VR and AR technologies hold great promise for hip-related surgeries, especially for preoperative operation simulation and training, feasibility applications in the operating room, and postoperative rehabilitation, and have the potential to assist orthopedic surgeons in operating more accurately and safely. More comparative studies are necessary, including studies focusing on clinical outcomes and cost-effectiveness.


Subject(s)
Augmented Reality , Surgery, Computer-Assisted , Virtual Reality , Humans , Cadaver , Operating Rooms , Surgery, Computer-Assisted/methods
11.
BMC Musculoskelet Disord ; 23(1): 981, 2022 Nov 12.
Article in English | MEDLINE | ID: mdl-36371233

ABSTRACT

BACKGROUND: This study performed a randomized trial data meta-analysis to assess The Modified Brostrom-Gould (MBG) for proven chronic lateral ankle instability (CLAI). METHODS: All published randomized clinical trials comparing MBG and other operations were found by searching the Cochrane Library, EMBASE, and PubMed databases. The Review Manager 5.4 software was used to compare the two groups regarding postoperative functional score, ankle stability, and complications. Risk Ratio (RR) and Mean Differences (MD) were used in meta-analyses. RESULTS: 8 experiments are suitable for it, 426 patients were enrolled, and 222 patients underwent other operations surgery. Among the six outcome indicators, in terms of FAOS scores, the other operations group has an advantage, 6.53 points higher than MBG; others show no significant differences. CONCLUSIONS: Based on this meta-analysis, the authors believe that other surgical groups can achieve better outcomes than MBG in some aspects of CLAI treatment.


Subject(s)
Joint Instability , Lateral Ligament, Ankle , Humans , Ankle Joint/surgery , Ankle , Joint Instability/surgery , Lateral Ligament, Ankle/surgery , Postoperative Period
12.
Environ Sci Ecotechnol ; 11: 100186, 2022 Jul.
Article in English | MEDLINE | ID: mdl-36158760

ABSTRACT

Traditional bioelectrochemical systems (BESs) coupled with stripping units for ammonia recovery suffer from an insufficient supply of electron acceptors due to the low solubility of oxygen. In this study, we proposed a novel strategy to efficiently transport the oxidizing equivalent provided at the stripping unit to the cathode by introducing a highly soluble electron mediator (EM) into the catholyte. To validate this strategy, we developed a new kind of iron complex system (tartrate-EDTA-Fe) as the EM. EDTA-Fe contributed to the redox property with a midpoint potential of -0.075 V (vs. standard hydrogen electrode, SHE) at pH 10, whereas tartrate acted as a stabilizer to avoid iron precipitation under alkaline conditions. At a ratio of the catholyte recirculation rate to the anolyte flow rate (RC-A) of 12, the NH4 +-N recovery rate in the system with 50 mM tartrate-EDTA-Fe complex reached 6.9 ±â€¯0.2 g N m-2 d-1, approximately 3.8 times higher than that in the non-EM control. With the help of the complex, our system showed an NH4 +-N recovery performance comparable to that previously reported but with an extremely low RC-A (0.5 vs. 288). The strategy proposed here may guide the future of ammonia recovery BES scale-up because the introduction of an EM allows aeration to be performed only at the stripping unit instead of at every cathode, which is beneficial for the system design due to its simplicity and reliability.

13.
Inorg Chem ; 61(31): 12293-12300, 2022 Aug 08.
Article in English | MEDLINE | ID: mdl-35894558

ABSTRACT

The inferior electrical properties at the interface of the Cu2ZnSnS4/CdS (CZTS/CdS) heterojunction resulting in the severe loss of open-circuit voltage (Voc) highly restrict the photovoltaic efficiency of CZTS solar cell devices. Here, first-principles calculations show that the Zn-alloyed CdS buffer layer reverses the unfavorable cliff-like conduction band offset (CBO) of CZTS/CdS to the desirable spike-like CBO of CZTS/Zn0.25Cd0.75S, which suppresses carrier nonradiative recombination and blocks electron backflow. In addition, the weakened n-type conductivity of Zn0.25Cd0.75S can be enhanced by In, Ga, and Cl doping without the introduction of detrimental deep-level defects and severe band-tail states, which improves the Voc of CZTS solar cells by promoting strong band bending and large quasi-Fermi-level splitting at the absorber side of the CZTS/Zn0.25Cd0.75S heterojunction. This study finds that the synergetic effects of Zn alloying and defect engineering on the CdS buffer layer are promising for overcoming the long-standing issue of the Voc deficit in CZTS solar cells, and understanding the optimized interfacial electrical properties provides theoretical guidance for improving the efficiency of semiconductor devices.

14.
Phys Chem Chem Phys ; 24(12): 7512-7520, 2022 Mar 23.
Article in English | MEDLINE | ID: mdl-35289820

ABSTRACT

Elemental two-dimensional (2D) materials have attracted extraordinary interest compared with other 2D materials over the past few years. Fifteen elements from group IIIA to VIA have been discussed experimentally or theoretically for the formation of 2D monolayers, and the remaining few elements still need to be identified. Here, using first-principles calculations within density functional theory (DFT) and ab initio molecular dynamics simulations (AIMDs), we demonstrated that polonium can form stable 2D monolayers (MLs) with a 1T-MoS2-like structure. The band structure calculations revealed that polonium monolayers possess strong semiconducting properties with a band gap of ∼0.9 eV, and such semiconducting properties can well sustain up to a thickness of 4 MLs with a bandgap of ∼0.1 eV. We also found that polonium monolayers can be achieved through a spontaneous phase transition of ultrathin films with magic thicknesses, resulting in a weaker van der Waals interaction of ∼32 meV Å-2 between each three atomic layers. Also, the underlying physics comes from layered Peierls-like distortion driven by strong quantum size effects. Based on these intriguing findings, a suitable substrate on which the polonium monolayer can be grown through an epitaxial growth technique is proposed for further experiments. Our work not only extends completely the puzzle of elemental 2D monolayer materials from group IIIA to VIA, but also presents a new formation mechanism of 2D materials beyond the database of bulk materials with layered van der Waals interactions.

15.
Materials (Basel) ; 15(2)2022 Jan 06.
Article in English | MEDLINE | ID: mdl-35057127

ABSTRACT

Lead-free and eco-friendly GeTe shows promising mid-temperature thermoelectric applications. However, a low Seebeck coefficient due to its intrinsically high hole concentration induced by Ge vacancies, and a relatively high thermal conductivity result in inferior thermoelectric performance in pristine GeTe. Extrinsic dopants such as Sb, Bi, and Y could play a crucial role in regulating the hole concentration of GeTe because of their different valence states as cations and high solubility in GeTe. Here we investigate the thermoelectric performance of GeTe upon Sb doping, and demonstrate a high maximum zT value up to 1.88 in Ge0.90Sb0.10Te as a result of the significant suppression in thermal conductivity while maintaining a high power factor. The maintained high power factor is due to the markable enhancement in the Seebeck coefficient, which could be attributed to the significant suppression of hole concentration and the valence band convergence upon Sb doping, while the low thermal conductivity stems from the suppression of electronic thermal conductivity due to the increase in electrical resistivity and the lowering of lattice thermal conductivity through strengthening the phonon scattering by lattice distortion, dislocations, and twin boundaries. The excellent thermoelectric performance of Ge0.90Sb0.10Te shows good reproducibility and thermal stability. This work confirms that Ge0.90Sb0.10Te is a superior thermoelectric material for practical application.

16.
J Phys Chem Lett ; 13(3): 740-746, 2022 Jan 27.
Article in English | MEDLINE | ID: mdl-35029120

ABSTRACT

Surface Van Hove singularity (SVHS) triggers exciting physical phenomena distinct from the bulk. Herein, we explore the potential role of SVHS in catalysis for both CO oxidation and the hydrogen evolution reaction (HER) using the graphene/Ca2N (Gra/Ca2N) heterojunction and Pt2HgSe3 (001) surface as prototype systems. It is demonstrated that both systems with SVHS could serve as an electron bath to promote O2 adsorption and subsequent CO oxidation with low energy barriers of 0.2-0.6 eV for the Gra/Ca2N and Pt2HgSe3 (001) surface and similarly facilitate the HER with near-zero hydrogen adsorption free energy. Importantly, the catalytically active sites associated with SVHS are well-defined and distributed over the whole surface plane, and further, the chemical reactivity of SVHS can also be tuned easily via adjusting its position with respect to EF. Our study demonstrates the enabling power of SVHS and provides novel physical insights into the promising potential role of VHS in designing high-efficiency catalysts.

17.
ACS Appl Mater Interfaces ; 14(1): 1045-1055, 2022 Jan 12.
Article in English | MEDLINE | ID: mdl-34965726

ABSTRACT

Wearable thermoelectric generators (w-TEGs) can incessantly convert body heat into electricity to power electronics. However, the low efficiency of thermoelectric materials, tiny terminal temperature difference, rigidity, and negligence of lateral heat transfer preclude broad utilization of w-TEGs. In this work, we employ finite element simulation to find the key factors for simultaneous realization of flexibility and ultrahigh normalized power density. Using melamine foam with an ultralow thermal conductivity (0.03 W/m K) as the encapsulation material, a novel lightweight π-type w-TEG with no heatsink and excellent stretchability, comfortability, processability, and cost efficiency has been fabricated. At an ambient temperature of 24 °C, the maximum power density of the w-TEG reached 7 µW/cm2 (sitting) and 29 µW/cm2 (walking). Under suitable heat exchange conditions (heatsink with 1 m/s air velocity), 32 pairs of w-TEGs can generate 66 mV voltage and 60 µW/cm2 power density. The output performance of our TEG is remarkably superior to that of previously reported w-TEGs. Besides, the practicality of our w-TEG was showcased by successfully driving a quartz watch at room temperature.

18.
Phys Chem Chem Phys ; 23(43): 24814-24822, 2021 Nov 10.
Article in English | MEDLINE | ID: mdl-34714310

ABSTRACT

Nowadays, one of the most typical and important potential applications of negative thermal expansion (NTE) materials is to prepare zero thermal expansion or controllable coefficient thermal expansion materials by compounding them with positive thermal expansion materials. The research on NTE properties at the nanoscales is the basis and premise for the realization of high-quality composites. Here, using first-principles calculations, we take a typical open framework material ScF3 as an example to study a new NTE mechanism at the nanoscale, which involves edge and size effects, as well as crystal symmetry breaking. By analyzing the vibrational modes in ultrathin ScF3 films, three effects contributing to the NTE properties are identified, namely, the acoustic mode (ZA mode) induced by surface truncation, the enhanced rotations of ScF6 octahedra in the surface layer and the suppressed rotations of ScF6 octahedra in the inner layer due to crystal symmetry breaking. With increasing thickness, the effect of the ZA mode vibration gradually weakens, while the rotations of the ScF6 octahedra in the surface and inner layers are enhanced. Ultimately, the approximately mutual compensation of these three effects makes the NTE coefficients of different thicknesses almost unchanged. Finally, we simply generalize our conclusions to zero dimensional nanoparticles. This work reveals a new NTE mechanism in low-dimensional open framework materials, which serves as a guide in designing NTE materials at the nanoscale.

19.
ACS Appl Mater Interfaces ; 13(41): 48801-48809, 2021 Oct 20.
Article in English | MEDLINE | ID: mdl-34618429

ABSTRACT

Half-Heusler alloys, which possess the advantages of high thermal stability, a large power factor, and good mechanical property, have been attracting increasing interest in mid-temperature thermoelectric applications. In this work, extra Zr-doped TiZrxNiSn samples were successfully prepared by a modified solid-state reaction followed by spark plasma sintering. It demonstrates that extra Zr doping could not only improve the power factor on account of an increase in the Seebeck coefficient but also suppress the lattice thermal conductivity originated from the strengthened phonon scattering by the superlattice nanodomains and the secondary nanoparticles. As a consequence, an increased power factor of 3.29 mW m-1 K-2 and a decreased lattice thermal conductivity of 1.74 W m-1 K-1 are achieved in TiZr0.015NiSn, leading to a peak ZT as high as 0.88 at 773 K and an average ZT value up to 0.62 in the temperature range of 373-773 K. This work gives guidance for optimizing the thermoelectric performance of TiNiSn-based alloys by modulating the microstructures on the secondary nanophases and superlattice nanodomains.

20.
ACS Appl Mater Interfaces ; 13(28): 32876-32885, 2021 Jul 21.
Article in English | MEDLINE | ID: mdl-34242005

ABSTRACT

As a lead-free thermoelectric material, SnTe is inhibited by its inherent high carrier concentration and high thermal conductivity. This work describes the synergistic effect on the modulation of band structure and microstructural defects of SnTe by Ag and Y codoping, which gives rise to band convergence and multiple microstructural defects (secondary phases, dislocations, and boundaries) in the matrix and endows Sn0.94Ag0.09Y0.05Te with an increased power factor of ∼2485 µW m-1 K-2, an extremely low lattice thermal conductivity of ∼0.61 W m-1 K-1, and a peak zT as high as ∼1.2 at 873 K. This work reveals that the combination of Ag and Y could play a role in the synergistic optimization of electronic and phonon transport properties of SnTe by modifying the band structure and microstructures, providing guidance for enhancing the thermoelectric performance of the relevant materials.

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