P‐type polycrystalline SnSe and K0.01Sn0.99Se are prepared by combining mechanical alloying (MA) and spark plasma sintering (SPS). The highest ZT of ≈0.65 is obtained at 773 K for undoped SnSe by ...optimizing the MA time. To enhance the electrical transport properties of SnSe, K is selected as an effective dopant. It is found that the maximal power factor can be enhanced significantly from ≈280 μW m−1 K−2 for undoped SnSe to ≈350 μW m−1 K−2 for K‐doped SnSe. It is also observed that the thermal conductivity of polycrystalline SnSe can be enhanced if the SnSe powders are slightly oxidized. Surprisingly, after K doping, the absence of Sn oxides at grain boundaries and the presence of coherent nanoprecipitates in the SnSe matrix contribute to an impressively low lattice thermal conductivity of ≈0.20 W m−1 K−1 at 773 K along the sample section perpendicular to pressing direction of SPS. This extremely low lattice thermal conductivity coupled with the enhanced power factor results in a record high ZT of ≈1.1 at 773 K along this direction in polycrystalline SnSe.
The thermal conductivity significantly decreases after K doping in polycrystalline SnSe. The absence of Sn oxides at the grain boundaries and presence of coherent nanoprecipitates in SnSe matrix result in an impressively low lattice thermal conductivity. Coupled with enhanced power factor results in a maximum figure of merit (ZT) ≈ 1.1 at 773 K, which is the highest value ever reported in polycrystalline SnSe.
Inorganic films possess much higher thermoelectric performance than their organic counterparts, but their poor flexibilities limit their practical applications. Here, Sb2Te3/Tex hybrid thin films ...with high thermoelectric performance and flexibility, fabricated via a novel directional thermal diffusion reaction growth method are reported. The directional thermal diffusion enables rationally tuning the Te content in Sb2Te3, which optimizes the carrier density and leads to a significantly enhanced power factor of >20 µW cm–1 K–2, confirmed by both first‐principles calculations and experiments; while dense boundaries between Te and Sb2Te3 nanophases, contribute to the low thermal conductivity of ≈0.86 W m–1 K–1, both induce a high ZT of ≈1 in (Sb2Te3)(Te)1.5 at 453 K, ranking as the top value among the reported flexible films. Besides, thin films also exhibit extraordinary flexibility. A rationally designed flexible device composed of (Sb2Te3)(Te)1.5 thin films as p‐type legs and Bi2Te3 thin films as n‐type legs shows a high power density of >280 µW cm–2 at a temperature difference of 20 K, indicating a great potential for sustainably charging low‐power electronics.
A high ZT of ≈1 at 453 K is achieved in an inorganic Sb2Te3/Te hybrid thin film via a novel directional thermal diffusion reaction growth method with extraordinary flexibility, and the rationally designed flexible device shows a high power density by a low‐temperature difference.
SnSe has attracted much attention due to the excellent thermoelectric (TE) properties of both p‐ and n‐type single crystals. However, the TE performance of polycrystalline SnSe is still low, ...especially in n‐type materials, because SnSe is an intrinsic p‐type semiconductor. In this work, a three‐step doping process is employed on polycrystalline SnSe to make it n‐type and enhance its TE properties. It is found that the Sn0.97Re0.03Se0.93Cl0.02 sample achieves a peak ZT value of ≈1.5 at 798 K, which is the highest ZT reported, to date, in n‐type polycrystalline SnSe. This is attributed to the synergistic effects of a series of point defects: VSe.., ClSe.,VSn,,,ReSn×, Re 0. In those defects, the VSe.. compensates for the intrinsic Sn vacancies in SnSe, the ClSe. acts as a donor, the VSn,, acts as an acceptor, all of which contribute to optimizing the carrier concentration. Rhenium (Re) doping surprisingly plays dual‐roles, in that it both significantly enhances the electrical transport properties and largely reduces the thermal conductivity by introducing the point defects, ReSn×, Re 0. The method paves the way for obtaining high‐performance TE properties in SnSe crystals using multipoint‐defect synergy via a step‐by‐step multielement doping methodology.
In this work, point defect engineering is employed for changing the carrier species, enhancing the electrical transport properties, and reducing the thermal conductivity of the SnSe polycrystal. An n‐type Sn0.97Re0.03Se0.93Cl0.02 bulk sample achieves a peak ZT of 1.5 at 798 K, the highest value recorded for an n‐type SnSe polycrystalline sample.
The article adopts Unity 3D and Leap Motion technology to develop the interaction scene and creates modules, including pottery knowledge learning, virtual pottery gesture teaching, and pottery work ...display. Pottery knowledge and gestures are taught to students through virtual teacher guidance and gesture interaction. At the same time, grid structure definition, vertex calculation, and feature representation techniques are used for modeling and extracting features from pottery works. In terms of knowledge point mastery and work creativity, students using the virtual pottery system perform significantly better than traditional teaching methods according to teaching practice. For example, the knowledge point mastery scores of the virtual group were considerably higher than those of the conventional paper-and-pencil and clay groups (P<0.05), and the creativity scores of the works were significantly better than those of the control group (P<0.001). In addition, students’ learning engagement (including cognitive, affective, and social engagement) was significantly improved in the virtual group. By combining big data technology and virtual reality technology, the teaching effectiveness of pottery education in higher vocational schools has improved dramatically. The virtual pottery teaching system enhances students’ mastery of knowledge points and creativity of works while also enhancing their learning engagement, demonstrating the significance and potential of technology in art education.
Flexible Bi2Te3‐based thermoelectric devices can function as power generators for powering wearable electronics or chip‐sensors for internet‐of‐things. However, the unsatisfied performance of n‐type ...Bi2Te3 flexible thin films significantly limits their wide application. In this study, a novel thermal diffusion method is employed to fabricate n‐type Te‐embedded Bi2Te3 flexible thin films on flexible polyimide substrates, where Te embeddings can be achieved by tuning the thermal diffusion temperature and correspondingly result in an energy filtering effect at the Bi2Te3/Te interfaces. The energy filtering effect can lead to a high Seebeck coefficient ≈160 µV K−1 as well as high carrier mobility of ≈200 cm2 V−1 s−1 at room‐temperature. Consequently, an ultrahigh room‐temperature power factor of 14.65 µW cm−1 K−2 can be observed in the Te‐embedded Bi2Te3 flexible thin films prepared at the diffusion temperature of 623 K. A thermoelectric sensor is also assembled through integrating the n‐type Bi2Te3 flexible thin films with p‐type Sb2Te3 counterparts, which can fast reflect finger‐touch status and demonstrate the applicability of as‐prepared Te‐embedded Bi2Te3 flexible thin films. This study indicates that the thermal diffusion method is an effective way to fabricate high‐performance and applicable flexible Te‐embedded Bi2Te3‐based thin films.
In this study, flexible n‐type Bi2Te3‐based thin‐films are successfully prepared through facile thermal diffusion method and further induce Te/Bi2Te3 heterojunctions and energy filtering effect at the Te/Bi2Te3 interfaces to optimize the thermoelectric performance through tuning the diffusion temperature.
Hierarchical porosity and functionalization help to fully make use of metal–organic frameworks (MOFs) for their diverse applications. Herein, a simple strategy is reported to construct hierarchically ...porous MOFs through a competitive coordination method using tetrafluoroborate (M(BF4)x, where M is metal site) as both functional sites and etching agents. The resulting MOFs have in situ formed defect‐mesopores and functional sites without sacrificing their structure stability. The formation mechanism of the defect‐mesopores is elucidated by a combination of experimental and first‐principles calculation method, indicating the general feasibility of this new approach. Compared with the original microporous counterparts, the new hierarchical MOFs exhibit superior adsorption for the bulky dye molecules and catalytic performance for the CO2 conversion attributed to their specific hierarchical pore structures.
A simple and novel strategy is reported to fabricate a series of hierarchically porous metal–organic frameworks through the competitive coordination method. The formation mechanism of defect‐mesopores is elucidated by a combination of experimental and first‐principles calculation methods. Furthermore, the adsorption and catalytic advantage over the original microporous counterparts is also demonstrated attributed to their specific hierarchical pore structures.
One kind of particularly interesting pseudoscalar particles, called axion-like particles (ALPs), have rich physical phenomenology at high- and low-energy collider experiments. After discussing most ...of single production channels of ALP at electron-positron colliders, we investigate the possibility of detecting this kind of new particles through the W
+
W
-
fusion process e
+
e
-
→
ν
¯
e
ν
e
a
(
→
γ
γ
)
at the CLIC. The 3
σ
and 5
σ
bounds on the ALP parameter space at the three energy stages of the CLIC are obtained. We find that the bounds given by the CLIC are complementary to the existing experiments exclusion regions.
The homojunction of oxygen/metal vacancies and its interfacial n–p effect on the physiochemical properties are rarely reported. Interfacial n–p homojunctions of TiO2 are fabricated by directly ...decorating interfacial p‐type titanium‐defected TiO2 around n‐type oxygen‐defected TiO2 nanocrystals in amorphous–anatase homogeneous nanostructures. Experimental measurements and theoretical calculations on the cell lattice parameters show that the homojunction of oxygen and titanium vacancies changes the charge density of TiO2; a strong EPR signal caused by oxygen vacancies and an unreported strong titanium vacancies signal of 2D 1H TQ‐SQ MAS NMR are present. Amorphous–anatase TiO2 shows significant performance regarding the photogeneration current, photocatalysis, and energy storage, owing to interfacial n‐type to p‐type conductivity with high charge mobility and less structural confinement of amorphous clusters. A new “homojunction of oxygen and titanium vacancies” concept, characteristics, and mechanism are proposed at an atomic‐/nanoscale to clarify the generation of oxygen vacancies and titanium vacancies as well as the interface electron transfer.
The homojunction of oxygen and titanium vacancies developed in the amorphous–anatase interface of nanostructured TiO2 results in a unique n–p electronic transmission, which is mostly preferred to the mobility of electronic charge carriers. It also contributes to significant performance regarding photogeneration current, photocatalysis, and energy storage.
A unique strain‐mediated lattice rotation strategy is introduced via nanocompositing to upsurge the optimized limits in the composition‐to‐structural pathway on rationally engineering the efficient ...thermoelectric material. In this study, a special lattice rotation via strain engineering is realized to optimize the desired electronic and chemical environment for enhancing thermoelectric properties in n‐type Bi2S2Se. This approach results in a unique transport phenomenon to assist high‐energy electrons in transferring through the optimized transport channels, and appropriate structure disparity to significantly localize phonons. As a result, Sb over Cl doping in Bi2S2Se gently reduces Eg and introduces defect states in bandgap with shifting down the Fermi level, thus causing increase in carrier concentration, which contributes to a higher power factor of ≈7.18 µW cm−1 K−2 (at T = 773 K). Besides, a lower thermal conductivity of ≈0.49 W m−1 K−1 is driven through lattice strain and defect engineering. Consequently, an ultra‐high ZTmax = 1.13 (at T = 773 K) and a high ZTave = 0.54 (323 K‐773 K) are realized. This study not only leads to an extraordinary thermoelectric performance but also reveals a unique paradigm for electron transportation and phonon localization via lattice strain engineering.
A unique strain‐mediated lattice rotation strategy is introduced via nanocompositing to upsurge the optimized limits in the composition‐to‐structural pathway on rationally engineering the efficient thermoelectric material. The obtained ultra‐high ZTmax (=1.13 at T = 773 K) successfully demonstrates the effectiveness of doping‐induced structural variation and lattice rotation strategy, unlocking new prospects to develop atomistic lattice engineering in thermoelectric materials.
The occurrence of cancer metastasis may be related to stem cells in normal tissues. We searched for patient IDs with both normal tissue stem cell values and TCGA (The Cancer Genome Atlas) clinical ...data for pairing and obtained 639 sets of data (stemness index of normal tissue, stemness index of tumor tissue, cancer stage, distant metastasis, tumor size) and invasion, and lymph node involvement). However, clinical data on cancer metastasis are of only four stages (e.g., Stage I, II, III, and IV), which cannot show subtle changes continuously. We need to find an effective data mining method to transform this four-valued clinical description into a numerical curve. We data-mine this data through numericalization, sorting, and noise reduction filtering. The results showed that: as the normal tissue stemness value (NS) increased, the tumor tissue stemness value (TS) increased proportionally (1.26 times NS). When NS >0.5, the rate of change in TS decelerated (0.43 times NS), and tumor metastasis began to occur. Clinical indicators, such as cancer stage, distant metastasis, tumor size and invasion, and lymph node involvement, showed that tumor metastasis became more and more severe with the increase of NS. This study suggests that tumor metastasis is triggered when the NS in the patient's body is more significant than 0.5.
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