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Background: Fluorescence in situ hybridization (FISH) has become a popular biomarker for subsequent monitoring the recurrence of non-muscle invasive bladder cancer (NMIBC), several studies have investigated the ability of FISH to detect recurrence in the surveillance of NMIBC. However, the results were inconsistent. Methods: We conducted a systematic literature search extensively on authenticated databases including PubMed/Medline, Embase, Web of Science, Ovid, and Cochrane Library. Meta-analysis was performed to find out the sensitivity and specificity of FISH in predicting recurrence of NMIBC. Results: 15 studies were ultimately included in this meta-analysis, a total of 2941 FISH evaluations from 2385 NMIBC patients were available. The pooled sensitivity of FISH was 68% (95% CI: 0.58–0.76), and the pooled specificity was 64% (95% CI: 0.53–0.74). Subgroup analyses were performed in 7 studies without Bacillus Calmette–Guerin (BCG) treatment, the pooled sensitivity was 82% (95% CI: 0.68–0.90), and the pooled specificity was 63% (95% CI: 0.37–0.82). And in 9 studies using "UroVysion standard" to define positive FISH results showed a pooled sensitivity of 60% (95% CI: 0.50–0.70) and specificity of 70% (95% CI: 0.61–0.78). Conclusions: The findings of this study indicate that FISH has a satisfactory sensitivity (68%) and specificity (64%) and could be a potential biomarker in the surveillance of NMIBC. Moreover, BCG treatment and different FISH methods may have an impact on the sensitivity and specificity, these factors should be taken into account when making clinical strategy. [ABSTRACT FROM AUTHOR]

Chondromalacia patellae (CMP), also known as runner's knee, typically occurs in young patients, which is characterized by anterior knee pain (AKP) that is associated with visible changes in patellar cartilage. The initial pathological changes include cartilage softening, swelling, and edema. CMP is caused by several factors, including trauma, increased cartilage vulnerability, patellofemoral instability, bony anatomic variations, abnormal patellar kinematics, and occupation hazards. CMP may be reversible or may progress to develop patellofemoral osteoarthritis. Quadriceps wasting, patellofemoral crepitus, and effusion are obvious clinical indications. Additionally, radiological examinations are also necessary for diagnosis. Magnetic resonance imaging (MRI) is a non-invasive diagnostic method, which holds a promise in having the unique ability to potentially identify cartilage lesions. Modalities are conventionally proposed to treat cartilage lesions in the PF joint, but none have emerged as a gold standard, neither to alleviated symptoms and function nor to prevent OA degeneration. Recently, researchers have been focused on cartilage-targeted therapy. Various efforts including cell therapy and tissue emerge for cartilage regeneration exhibit as the promising regime, especially in the application of mesenchymal stem cells (MSCs). Intra-articular injections of variously sourced MSC are found safe and beneficial for treating CMP with improved clinical parameters, less invasiveness, symptomatic relief, and reduced inflammation. The mechanism of MSC injection remains further clinical investigation and is tremendously promising for CMP treatment. In this short review, etiology, MRI diagnosis, and treatment in CMP, especially the treatment of the cell-based therapies, are reviewed. [ABSTRACT FROM AUTHOR]

Preclinical and clinical studies have suggested potential synergies of combining poly (ADP-ribose) polymerase (PARP) inhibitors and novel hormonal therapies (NHT) for patients with metastatic castration-resistant prostate cancer (mCRPC). We systematically searched PubMed, ClinicalTrials.gov and ASCO-GU annual meeting abstracts up to March 2023 to identify potential phase III trials reporting the use of combining PARP inhibitors with NHT in the first-line setting for mCRPC. A total of four phase III trials met the criteria for subsequent review. Emerging data suggested that the radiographic progression-free survival (rPFS) was significantly longer in the PARP inhibitor combined with NHT group versus the placebo plus NHT group for the first-line setting of biomarker-unselected mCRPC patients, especially for patients with homologous recombination repair (HRR) mutation (HRR m), and with the greatest benefit for BRCA1/2 mutation (BRCA1/2 m) populations. Final overall survival (OS) data of the PROpel trial indicated a significant improvement in median OS for mCRPC patients with HRR m and BRCA1/2 m receiving olaparib + abiraterone. Prior taxane-based chemotherapy might not influence the efficacy of the combination. Compared with the current standard-of-care therapies, combining NHT with PARP inhibitors could achieve a significant survival benefit in the first-line setting for mCRPC patients with HRR and BRCA1/2 mutations. [ABSTRACT FROM AUTHOR]

Plasmonic modulation of the catalytic performances of metallic nanostructures shows great potential in the development of novel materials for catalysis. In addition to the challenges of devising new catalysts with high activity while maintaining controllable plasmonic properties, the mechanisms underlying the enhancement of the activity by surface plasmon resonance (SPR) are still under exploration. Here, we design a Pd-Au bimetallic hetero structure and use the well-defined SPR property of the core Au NPs to tune its surface electro catalytic activity. The hot electrons are transferred into the Pd nanopetals from the Au core with visible-light irradiation, resulting in an enhancement of the electrocatalytic oxidation of ethanol on Au concurrent with an inhibition on Pd. The anti-poisoning and stability of the as-prepared heterostructures is also enhanced by visible-light irradiation. [ABSTRACT FROM AUTHOR]

We report density functional studies of electron rich interfaces between KTaO3 or KNbO3 and CaSnO3 or ZnSnO3 and in particular the nature of the interfacial electron gasses that can be formed. We find that depending on the details these may occur on either the transition metal or stannate sides of the interface and in the later case can be shifted away from the interface by ferroelectricity. We also present calculations for bulk KNbO3, KTaO3, CaSnO3, BaSnO3 and ZnSnO3, showing the different transport and optical properties that may be expected on the two sides of such interfaces. The results suggest that these interfaces may display a wide range of behaviors depending on conditions, and in particular the interplay with ferroelectricity suggests that electrical control of these properties may be possible. [ABSTRACT FROM AUTHOR]

Highlights: All the synthesis routes and surfaced-modified strategy of MXene-derived quantum dots (MQDs), the synthesis of MQDs-based nanocomposites, and advanced characterization techniques of MQDs are fully covered. Catalytic application is classified and discussed by judging the roles of MQDs. Current challenge and prospect are proposed for promoting the development and catalytic application of MQDs.It is well known that two-dimensional (2D) MXene-derived quantum dots (MQDs) inherit the excellent physicochemical properties of the parental MXenes, as a Chinese proverb says, “Indigo blue is extracted from the indigo plant, but is bluer than the plant it comes from.” Therefore, 0D QDs harvest larger surface-to-volume ratio, outstanding optical properties, and vigorous quantum confinement effect. Currently, MQDs trigger enormous research enthusiasm as an emerging star of functional materials applied to physics, chemistry, biology, energy conversion, and storage. Since the surface properties of small-sized MQDs include the type of surface functional groups, the functionalized surface directly determines their performance. As the Nobel Laureate Wolfgang Pauli says, “God made the bulk, but the surface was invented by the devil,” and it is just on the basis of the abundant surface functional groups, there is lots of space to be thereof excavated from MQDs. We are witnessing such excellence and even more promising to be expected. Nowadays, MQDs have been widely applied to catalysis, whereas the related reviews are rarely reported. Herein, we provide a state-of-the-art overview of MQDs in catalysis over the past five years, ranging from the origin and development of MQDs, synthetic routes of MQDs, and functionalized MQDs to advanced characterization techniques. To explore the diversity of catalytic application and perspectives of MQDs, our review will stimulate more efforts toward the synthesis of optimal MQDs and thereof designing high-performance MQDs-based catalysts. [ABSTRACT FROM AUTHOR]

Schematic diagram representation the introduction of selenium and iron synergistically modulate the d-band center of Ni 3 S 2 to enhance oxygen evolution reaction (OER) and urea oxidation reaction (UOR). [Display omitted] • The introduction of selenium and iron synergistically modulated the d-band center of Ni 3 S 2 , resulting in the enhanced catalytic activity for the oxygen evolution reaction (OER) and urea oxidation reaction (UOR). • By adjusting the position of the d-band center, it is possible to optimize the adsorption and desorption energies of SeFe-Ni 3 S 2 towards urea molecules, as well as the overpotential for OER (η OER) and the limiting potential for UOR (U L). • The synthesized SeFe-Ni 3 S 2 presents as 3.9 nm lamellar structure with a larger specific surface area leading to the exposure of more active sites. Efficient production of green hydrogen energy is crucial in addressing the energy crisis and environmental concerns. The oxygen evolution reaction (OER) poses a challenge in conventional overall water electrolysis due to its slow thermodynamically process. Urea oxidation reaction (UOR) offers an alternative anodic oxidation method that is highly efficient and cost-effective, with favorable thermodynamics and sustainability. Recently, there has been limited research on bifunctional catalysts that exhibit excellent activity for both OER and UOR reactions. In this study, we developed a selenium and iron co-doped nickel sulfide (SeFe-Ni 3 S 2) catalyst that demonstrated excellent Tafel slopes of 53.9 mV dec−1 and 16.4 mV dec−1 for OER and UOR, respectively. Density Functional Theory (DFT) calculations revealed that the introduction of metal (iron) and nonmetallic elements (selenium) was found to coordinate the d-band center, resulting in improved adsorption/desorption energies of the catalysts and reduced the overpotentials and limiting potentials for OER and UOR, respectively. This activity enhancement can be attributed to the altered electronic coordination structure after the introduction of selenium (Se) and iron (Fe), leading to an increase in the intrinsic activity of the catalyst. This work offers a new strategy for bifunctional catalysts for OER and UOR, presenting new possibilities for the future development of hydrogen production and novel energy conversion technologies. It contributes towards the urgent search for technologies that efficiently produce green hydrogen energy, providing potential solutions to mitigate the energy crisis and protect the environment. [ABSTRACT FROM AUTHOR]

To summarize and indirectly compare the efficacy and safety of different second-line systematic therapies after first-line androgen-receptor targeting therapies (ARTs) for biomarker-unselected metastatic castration-resistant prostate cancer (mCRPC) patients. Studies published in English up to May 2023 were identified in PubMed, Web of Science and ASCO-GU 2023. Studies accessing the efficacy and safety of second-line systematic therapies after first-line ARTs for biomarker-unselected mCRPC patients were eligible for current systematic review and network meta-analysis (NMA). Thirty-two studies with 5388 patients and 10 unique treatment modalities met our inclusion criteria. Current evidence suggested that docetaxel (DOC) combined with the same ART as first-line (ART1) (ART1 + DOC) were associated with significantly improved PSA response, PSA progression-free survival (PFS) and clinical or radiographic PFS (rPFS) compared with other reported second-line systematic therapies, including DOC. An increase in toxicity was observed with ART1 + DOC. Our NMA indicated that DOC monotherapy was only inferior to ART1 + DOC in improvement disease outcomes. The incidence of toxicity between patients received second-line DOC and an alternative ART (ART2) was similar. The available evidence reviewed in our work suggested a clinical benefit of DOC nomotherapy and DOC plus ART1 as the second-line systematic therapy for biomarker-unselected mCRPC patients progressed on a first-line ART. More studies and RCTs are needed to evaluate the optimal second-line treatments for mCRPC patients with one prior first-line ART. [Display omitted] • DOC and DOC + ART1 seems to be most beneficial for clinical benefit. • More studies and RCTs are needed to evaluate the optimal second-line treatments patients received DOC+ART1 had an increased incidence of grade ≥ 3 AEs. [ABSTRACT FROM AUTHOR]

Seeking new cathode chemistry with high onset potential and compatibility with electrolytes has become a challenge for aqueous Zn ion batteries. Anion intercalation in graphite (4.5 V vs Li+/Li) possesses the potentiality but usually shows a competitive relationship with oxygen evolution reaction (OER) in aqueous solutions. Herein, a decoupled design is proposed to optimize a full utilization of perchlorate ion intercalation in graphite cathode by pH adjustment. Benefiting from the decoupled design, high Coulombic efficiency is obtained by decelerating the kinetic of OER in acidic media. The decoupled Zn‐graphite battery exhibits a wide potential window of 2.01 V, as well as an attractive energy density of 231 Wh kg−1. In addition, a Zn‐graphite battery with SO42−${\mathrm{SO}}_4^{2 - }$ insertion is assembled, which demonstrates the capability of the proposed decoupled strategy to integrate novel electrode chemistries for high‐performance aqueous Zn‐based energy storage systems. [ABSTRACT FROM AUTHOR]

The utilization of conductive hydrogels, particularly in the domain of wearable technology, has garnered substantial attention. However, the limited mechanical properties, low sensitivity, and lack of multifunctionality in conventional conductive hydrogels constrain their potential applications. Thus, the endeavor to develop conductive hydrogels with exceptional comprehensive performance remains a formidable challenge. In this investigation, chitosan quaternary ammonium salts and the conductive polymer poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) were employed as precursor materials, incorporating carboxylated cellulose nanofibers, to synthesize a novel double-crosslinked network hydrogel. The resulting hydrogel specimen exhibited noteworthy tensile strength (2.13 MPa), significantly enhanced elongation (547%), favorable strain sensitivity (Gauge Factor ranging from 0.91 to 9.78), and electrical self-healing capabilities. Additionally, it demonstrated accurate detection of subtle human movements and conversion of raw data into binary data. This research provides valuable insights into the advancement of conductive hydrogels for wearable soft electronics. TOC : A double cross-linked network structure hydrogel with CNF–C: synergistically enhanced mechanical properties and sensitivity of flexible strain sensors. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: A unique atomic dispersed hetero-pair was successfully synthesized, consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier. This strategy breaks the linear scaling relationships of electrocatalytic CO2 reduction by simultaneously regulating the *COOH adsorption energy and *CO desorption energy. The as-prepared MoFe–N–C exhibits excellent performance for CO2RR to CO with a high turnover frequency (TOF) of 3336.21 h−1, CO Faradaic efficiency (FECO) of 95.96% at − 0.60 V (versus RHE) and outstanding stability. Electrochemical carbon dioxide reduction reaction (CO2RR) involves a variety of intermediates with highly correlated reaction and ad-desorption energies, hindering optimization of the catalytic activity. For example, increasing the binding of the *COOH to the active site will generally increase the *CO desorption energy. Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO2RR, but remains an unsolved challenge. Herein, we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier. This system shows an unprecedented CO2RR intrinsic activity with TOF of 3336 h−1, high selectivity toward CO production, Faradaic efficiency of 95.96% at − 0.60 V and excellent stability. Theoretical calculations show that the Mo-Fe diatomic sites increased the *COOH intermediate adsorption energy by bridging adsorption of *COOH intermediates. At the same time, d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of *CO intermediates. Thus, the undesirable correlation between these steps is broken. This work provides a promising approach, specifically the use of di-atoms, for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale. [ABSTRACT FROM AUTHOR]

Oxygen sensors, using organic-inorganic and all-inorganic lead halide perovskites, have demonstrated huge advantages in operating temperature, responding time, and reversing oxygen content detection. Nevertheless, the toxicity and instability issues hinder their wide application. In this work, for the first time, we report a sensitive fluorescence oxygen detector based on lead-free double perovskite Cs 2 AgBiBr 6 thin film. The sensor has a remarkable performance in terms of fast response time of ≈56 s, recovery time of ≈91 s, and a relatively low limit of detection (LOD) of 150 ppm. More importantly, the unencapsulated sensor still exhibits an obvious response at low oxygen concentrations after two-week storage in ambient, and the device also exhibits good humidity, light, and thermal stability. Consequently, the lead-free double perovskite (Cs 2 AgBiBr 6) will be promising environmentally friendly material in developing reversible, sensitive, high-efficiency, and stable perovskite oxygen sensors. [ABSTRACT FROM AUTHOR]

We consider how the device structure and the emitter properties determine the performance of near-infrared quantum dot based light-emitting diodes. The challenges and future prospects for such bright, stable and efficient devices are discussed. [Display omitted] Near-infrared (NIR) emitters are indispensable for telecommunication and medical applications. Colloidal semiconductor quantum dots offer plenty of advantages for NIR light-emitting diodes (LEDs) thanks to their size-dependent emission, high exciton binding energy, and low-cost solution processing. Here, we summarize the recent progress in the development of NIR quantum dot LEDs, focusing on how their device structure and emitter properties facilitate improvement of device performance. The challenges and opportunities associated with NIR quantum dot LEDs such as achieving the proper balance between the charge transport and exciton formation, enhancement of device stability, and improvement of device outcoupling efficiency are discussed. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanosheets materials have attracted extensive attention because of their promising practical application and theoretical values. In order to enhance the photocatalytic activity of bulk C 3 N 4 , we designed a 2D fabrication in which g-C 3 N 4 nanosheets was in the middle of MoS 2 /graphene layered structure. Here, we report an effective strategy to synthesize ternary g-C 3 N 4 /MoS 2 /graphene nanocomposite photocatalyst via an in-situ adsorption method, which exhibits superior photocatalytic activity owing to enhanced charge carrier separation via well-contacted interface and fast charge transfer pathway. This work indicates a new insight into the design of such 2D heterostructure and a promising cocatalyst strategy for designing a more efficient g-C 3 N 4 -based semiconductor photocatalyst toward degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

As a challenging problem in computer vision, salient object segmentation has attracted increasing attention in recent years. Though a lot of works based on encoder–decoder have been made, these methods can only recognize and segment one class of objects, but cannot segment the other classes of objects in the same image. To address this issue, this paper proposes a novel decoder based on Bayesian rules to perform task‐driven object segmentation, in which a control signal is added to the decoder to determine which class of objects need to be segmented. What's more, a Bayesian rule is established in the decoder, in which the control signal is set as the prior, and the latent features learned in encoder is transferred to the corresponding layer of decoder as observation, thus the posterior probability of each object with respect to the specific‐class can be calculated, and the objects belonging to this class can be segmented. This proposed method is evaluated for task‐driven salient object segmentation on several benchmark datasets, including MS COCO, DUT‐OMRON, ECSSD etc. Experimental results show that the approach tends to segment accurate, detailed, and complete objects, and improves the performance compared with the previous state‐of‐the‐art. [ABSTRACT FROM AUTHOR]

Efficient electrocatalytic reactions require a coordinated active center that may provide a properly reaction intermediates adsorption in water splitting. Herein, a Ni active center coordination reconstruction method achieved by multidimensional modulation of phase transition, iodine coordination, and vacancy defects is designed and implemented. This coordination reconstruction results in the successful synthesis of Ni5P4−xIx/Ni2P nanocorals that show outstanding bifunctional catalytic activity due to deep optimization of the adsorption energy. The overpotentials of hydrogen evolution reaction and oxygen evolution reaction at 10 mA cm−2 are 46 and 163 mV, respectively. Only 1.46 V is required to drive alkaline overall water splitting. Novel coordination environment is investigated by electron paramagnetic resonance spectroscopy and extended X‐ray absorption fine structure spectroscopy. A 4D integrated material design strategy of "thermodynamic stability‐electronic properties‐charge transfer‐adsorption energy" for water‐splitting catalysts is proposed. This coordination reconstruction concept and material design method provide new perspectives for the research of novel catalysts. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) perovskite materials show enormous potential in optoelectronic applications owing to their exceptional thermal stability and unique lattice structures. However, research into anion-substituted 2D perovskites is relatively rare, particularly in the photoelectric information storage field. Here, an anion-based 2D perovskite Cs 2 Pb(SCN) 2 I 2 film with high orientation and high thermal-stability is achieved by simple low-temperature solution processing and the memristor of Al/Cs 2 Pb(SCN) 2 I 2 /FTO is established. The experimental evidence shows that: 1) In the absence of light irradiation, memristors present typical bipolar resistance switching behaviour with On/Off resistance ratio (>103) and reliable retention (>104 s); 2) By introducing light irradiation, it can achieve a more dependable memristor with decreased RS fluctuation and improved cycling endurance. In addition, by modifying the compliance current (I cc), it can realize multi-level storage function of memories with good high temperature endurance. Finally, the logic gate function is also demonstrated with these cells. The operational principles of memristor devices are comprised of the charge trapping and conductive filament mechanisms. The light irradiation reduces the ion migration barrier and enhances the conductivity of perovskite films, thus limiting the excessive growth of conductive filaments. This work offers the groundwork for creating anionic two-dimensional perovskite photoelectric memristor devices. [ABSTRACT FROM AUTHOR]

The interface of perovskite solar cells (PSCs) determines their power conversion efficiency (PCE). Here, the buried bottom surface of a perovskite film is efficiently passivated by using MoS2 quantum dots. The perovskite films prepared on top of MoS2-assisted substrates show enhanced crystallinity, as evidenced by improved photoluminescence and a prolonged emission lifetime. MoS2 quantum dots with a large bandgap of 2.68 eV not only facilitate hole collection but also prevent the photogenerated electrons from flowing to the hole transport layer. Overall promotion leads to decreased trap density and an enhanced built-in electric field, thus increasing the device PCE from 17.87% to 19.95%. [ABSTRACT FROM AUTHOR]

[Display omitted] Carbon dots (CDs) emerge as promising luminescent materials for potential applications in optoelectronics on basis of their merits including low cost, eco-friendliness and strong, color-tunable photoluminescence (PL). However, the research on solid-state emissive CDs is still at the primary stage because of the aggregation-caused quenching (ACQ) of PL and their poor film-formation ability. In this work, we produce CDs with branched-polyethylenimine (b-PEI) chemically functionalized on the surfaces. The thus newly synthesized P-CDs successfully overcome the bottleneck of ACQ effect and display efficient red and NIR emission in aggregate state. Under the excitation of 520 nm, a strong red emission (maxima of 640 nm) with a high photoluminescence quantum yield (PLQY) of 21% was observed for the P-CDs in neat film. Moreover, this design strategy endows the P-CDs with good film-formation ability via solution spin-coating, which significantly increases its value for the film-based optoelectronic devices. [ABSTRACT FROM AUTHOR]

Robust superlubricity (RSL), defined by concurrent superlow friction and wear, holds great promise for reducing material and energy loss in vast industrial and technological operations. Despite recent advances, challenges remain in finding materials that exhibit RSL on macrolength and time scales and possess vigorous electrical conduction ability. Here, the discovery of RSL is reported on hydrated NbB2 films that exhibit vanishingly small coefficient of friction (0.001–0.006) and superlow wear rate (≈10−17 m3 N−1 m−1) on large length scales reaching millimeter range and prolonged time scales lasting through extensive loading durations. Moreover, the measured low resistivity (≈10−6 Ω m) of the synthesized NbB2 film indicates ample capability for electrical conduction, extending macroscale RSL to hitherto largely untapped metallic materials. Pertinent microscopic mechanisms are elucidated by deciphering the intricate load‐driven chemical reactions that generate and sustain the observed superlubricating state and assessing the strong stress responses under diverse strains that produce the superior durability. [ABSTRACT FROM AUTHOR]

Synthesized by dripping iron acetate into the N-doped carbon film enriched with pyridinic N and followed by annealing at 800 °C, Fe–N-doped amorphous carbon (d Fe–N -C) with an Fe content of 0.2 at.% showed excellent electrocatalytic activity, stability and methanol tolerance via a four-electron pathway for oxygen reduction reaction (ORR), which outperformed commercial Pt/C catalyst. More importantly, by tuning the Fe content and annealing temperature, the trace Fe in d Fe–N -C was supposed to form high active FeN 4 sites with pyridinic N and played an important role in the excellent electrocatalytic performance for ORR. [ABSTRACT FROM AUTHOR]

Patterned metal systems to periodically modulated nanomultilayered architectures, with crystalline and/or amorphous states, has acted as an effective strategy for tuning desirable mechanical properties. While the spontaneous assembly offers an effective and promising path for constructing nanomultilayers, in high-entropy alloys (HEA) how to trigger such a barrier-free route still faces challenges. In this paper, the enthalpy-difference-guided strategy, incorporating Pt, was employed to induce spinodal decomposition for the barrier-free nanomultilayer structure in refractory HEA systems. Aiming at exploring the elastic and chemical interactions, three HEA films with different degrees of size mismatch δ (Zr-Nb-Ta-Mo-W, Zr-Hf-Nb-Ta-Mo, Zr-Hf-Nb-Cr-Mo systems) were fabricated as model systems. Contributed by differences in ΔH mix and δ , in each HEA film, certain-content Pt can trigger both spinodal decomposition and amorphization behavior, which lead to the barrier-free Pt-rich/Pt-lean nanomultilayers with different topological combinations: crystalline/crystalline and amorphous/amorphous. Compared to model HEAs, such barrier-free nanomultilayers can significantly improve the nanoindentation hardness. In HEA systems, tuning ΔH mix and δ simultaneously can assist the further understanding of the structural arrangements and the progress on the barrier-free nanomultilayered configuration for superior mechanical properties. [Display omitted] [ABSTRACT FROM AUTHOR]

Nanostructured carbon materials have attracted enormous attention in last two decades due to their unique chemical, electrical, and mechanical properties. In this work, amorphous hollow carbon spheres (AHCSs) with diameters in the range of 100-750 nm, which are dispersed among bent graphitized carbon nanotubes, are synthesized by using radio frequency plasma enhanced chemical vapor deposition in mixed CH/H gases. The carbon spheres were characterized with scanning electron microscope, energy-dispersive X-ray spectroscopy, Raman spectroscopy, and transmission electron microscopy. It is found that MgO and Co/Ni nanoparticles as well as hydrogen play crucial roles in the formation of AHCSs. Moreover, a possible growth mechanism of AHCSs was proposed. The results of this study provide new insights into the fundamental understanding of nonstructural carbon materials toward applications in nanodevices. [ABSTRACT FROM AUTHOR]

The development of low-price and highly efficient catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has always been challenging with regard to water splitting. Pyrrhotite Fe 7 S 8 has become a research hotspot due to its abundant reserves, high electrical conductivity and excellent catalytic activity. In general, introducing metal heteroatoms into transition metal sulfides (TMSs) can effectively enhance the activity and stability of TMSs. Herein, Co-doped pyrrhotite Fe 7 S 8 nanosheets were obtained by a straightforward two-step method consisting of hydrothermal treatment followed by subsequent heat treatment. Results from XPS analysis and contact angle measurements showed that doping optimized the chemical environment around iron atoms and enhanced the adsorption of water molecules on the surface of Fe 7 S 8 , thereby greatly improving the electrocatalytic efficiency of water electrolysis. Compared with other counterparts, Co 0 · 95 Fe 6 · 05 S 8 exhibited superior OER activity with an overpotential of 311 mV at a current density of 10 mA cm−2, and higher performance towards HER with an overpotential of 284 mV at 10 mA cm−2 in alkaline solution. In sum, Co 0 · 95 Fe 6 · 05 S 8 is promising as a bifunctional catalyst for water splitting under alkaline conditions. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations are used to investigate the mechanical properties of finite‐width nanocrystalline gold nanoribbons with a thickness of one grain size under tensile strain. We find strong variations in the Young's modulus and flow stress especially for the sample with narrow width. With statistical analysis, Young's modulus has a trend of increase with the decrease of width. Flow stress does not follow this trend. Ductile fracture is observed at large strain in these nanocrystalline nanoribbons, but the fracture strain and mechanism are different from those of thick films as observed in existing experiments. For small widths below 80 nm, fracture is a necking effect, while for larger widths, shear bands and formation of nanovoids due to stress concentration are the main mechanism. Voids are mainly distributed in special GBs that are parallel to the direction of the maximum principal stress of the plastic deformation tensor. We find there is a width regime (about 80–130 nm) for the ultrathin nanoribbon gold, which have good ductility and large fracture strain. [ABSTRACT FROM AUTHOR]

Although one of the most promising aqueous batteries, all Zn‐Mn systems suffer from Zn dendrites and the low‐capacity Mn4+/Mn3+ process (readily leading to the occurrence of Jahn–Teller distortion, which in turn causes structural collapse and voltage/capacity fading). Here, the Mn3+ reconstruction and disproportionation are exploited to prepare the stable, Mn2+‐rich manganese oxides on carbon‐cloth (CMOs) in a discharged state through an inverted design, which promotes reversible Mn2+/Mn4+ kinetics and mitigates oxygen‐related redox activity. Such a 1.65 V Mn2+‐rich cathode enable constructing a 2.2 V Zn‐Mn battery, providing a high area capacity of 4.16 mA h cm–2 (25 mA h cm–2 for 10 mL electrolyte) and superior 4000‐cycle stability. Moreover, a flexible hybrid 2.7 V Zn‐Mn battery is constructed using 2‐pH hydrogel electrolytes to demonstrate excellent practicality and stability. A further insight has been gained to the commercial application of aqueous energy storage devices toward low‐cost, high safety, and excellent energy density. [ABSTRACT FROM AUTHOR]

• A universal strategy to solve interfacial detachment of solid EDLCs. • Significantly reduced interfacial impedance. • Optimizing solvated structures of Hybrid ILs. • Excellent cycling stability of EDLCs at high temperature. The growing application domain of energy storage devices (ESDs) is leading research to temperature tolerant supercapacitors. To realize reliable and safe devices, high modulus solid electrolytes are favored by most researchers. However, the inferior infiltrating ability of such electrolytes usually results in poor electrochemical performances of the ESDs. Herein, we adopted a hierarchical optimization strategy to address the aforementioned interfacial issues. Continuous ionic percolation throughout the hierarchical pores of the 3D electrode was formed by in-situ introducing an ionogel buffer layer. Benefiting from this, the rate of ions diffusing within electrodes was increased by 5 times. Furthermore, the kinetics of ions entering into nanopores was improved via introducing small size ions into ionic liquids (ILs) and adjusting the solvated structures. Both the capacity and rate performance of the electrochemical double layer capacitors (EDLCs) were improved. Additionally, the buffer layer exhibited sufficient thermostability to cooperate with poly(ether ether ketone) (PEEK)-based solid electrolyte. Consequently, the EDLCs exhibited excellent cycling stability (79% capacitance retention after 5000 cycles) at 120 °C and delivered a maximum energy density of 46.9 Wh kg−1 with a power density of 926.9 W kg−1. Our strategy is believed to be effective to cooperate with various solid electrolyte systems and offer a general design principle for durable and high performance EDLCs. [ABSTRACT FROM AUTHOR]

The electric double layer (EDL) has been found to play a critical role in not only electric double-layer capacitors (EDLCs) but also batteries and electrocatalysts. Although the influence of EDLs on the electrochemical behaviors of electrolytes has been extensively investigated, its influence on the electrode itself, particularly the energy storage mechanism, remains unclear. Herein, using popular α-Fe 2 O 3 , we look into the interaction between electrode and EDL and find the energy storage mechanism of an electrode can be tuned by modulating EDL. The EDL, which is mainly influenced by the inner Helmholtz plane (IHP) through the specific adsorption of ions onto the surface of Fe 2 O 3 , determines which ions are present at the interface and how they react with the electrode. Ultimately, the composition and properties of the EDL determine the energy storage mechanism of an Fe 2 O 3 electrode, including conversion reaction, ions insertion, surface redox reaction and pseudocapacitance. Our results not only provide a new understanding on the nature of the EDL but also demonstrate that the EDL should be promoted as a functional "component" which can be designed for achieving the optimum synergy of an electrode-electrolyte interface. [Display omitted] [ABSTRACT FROM AUTHOR]

Superlubricity is a sliding regime with almost vanishing friction sustained under stringent material conditions. This remarkable phenomenon was first found between surfaces with incommensurate lattice structures, and later extended to materials with weak shear, as in many two-dimensional layered materials. Such materials, however, face great challenges that limit their applications, including the difficulty to scale up to meet the needs of many practical implementations and low durability stemming from the intrinsic structural weakness. Overcoming these limitations hinges on new design and fabrication of advanced superlubricating materials. Here, we report on the realization of macroscale ultradurable superlubricity on passivated transition-metal diborides (TMB 2) following an unconventional design principle that first construct materials with strong anti-wear ability then create superlubricity via effective surface passivation. TMB 2 possess superior mechanical strength and durability, along with the ability to activate in-situ load-induced passivation layers via tribochemical actions at the surface. The resultant passivated TMB 2 exhibits characteristic superlubricating and ultradurable friction coefficient (0.002) and wear rate (10−19 m3/N·m). These findings introduce a fresh approach toward rational design and implementation of superlubricating materials, opening a new avenue for versatile applications at large (up to industrial) scales. [Display omitted] [ABSTRACT FROM AUTHOR]

Lead halide perovskite solar cells can be significantly improved with multifunctional additives such as carbon dots (CDs) with amine terminals via defect passivation and band alignment. Here, we determine rational guidelines for the usage of such quantum dots in perovskite solar cells by systematically studying their effects on crystal quality and carrier transport. The amine-terminated CDs homogeneously dispersed in precursors improve the crystal quality of perovskite films, but they reduce the hole mobility hampering hole extraction. In contrast, CDs deposited between the electron transport layer and active layer could promote spin-coated film quality and electron's extraction efficiently. So, the approaches of the carbon dots in device alters semiconductor properties and energy level structure. Interface engineering achieve better crystal quality and energy level alignment, which in turn affects charge collection, thereby increasing current density and power conversion efficiency. According to the findings of this study, when considering defect passivation by additives, the energy band alignment of the device should also be considered, since this could change carrier dynamics and device performance differently. [Display omitted] • Based on the effects of amine-terminated carbon dots, a rational guideline for the use of such CDs in perovskite solar cells was determined. • Carbon dots are able to passivate grain boundaries, optimize device interfaces, improve film morphology, align energy levels, and enhance carrier mobility. • The CDs homogeneously dispersed in precursors improve the crystal quality of perovskite films, but they increased energy barrier and hampered hole extraction. • The interface engineering via depositing the CDs between the electron transport layer and the active layer improves film quality and promotes electron extraction. • The interface engineering suggested comprehensive improvements over the precursor engineering, thereby leading to current density and power conversion efficiency changes. [ABSTRACT FROM AUTHOR]

A novel nitrogen-doped carbon nanosphere with lithiophilic ZnO nanoparticles encapsulated by interconnected pomegranate-like carbon sheets is designed and fabricated, and the lithium deposition behavior in it is systematically investigated via in-situ transmission electron microscopy. The well-designed pomegranate-like carbon sheets within the carbon nanosphere can prevent lithiophilic seeds from detaching or aggregating during cycling, and meanwhile offer individual void to accommodate deposited Li. Such a dual-confinement effect enables dendrite-free Li deposition and long cycling life. [Display omitted] • A novel pomegranate-like carbon nanosphere with lithiophilicity is constructed. • The well-designed carbon networks provide dual-confinement for Li encapsulation. • The ZnO@NPCS electrode delivers long cycling life with high average CEs. • In-situ TEM and phase-field simulations confirm the dual-confinement mechanism. • The dual-confinement strategy can be extended to other alkalis anodes. The uncontrollable dendrite growth and infinite volume expansion of Li during cycling lead to low Coulombic efficiency (CE) and short cycling life, severely impeding the commercial progress of lithium metal batteries (LMBs). In this work, nitrogen-doped carbon nanospheres (CSs) with ultrafine lithiophilic ZnO nanoparticles encapsulated by interconnected pomegranate-like carbon sheets (denoted as ZnO@NPCS) have been designed and constructed to serve as novel lithium hosts. The ultrafine ZnO nanoparticles uniformly distributed in the CSs can significantly reduce the Li nucleation barrier, while the well-designed pomegranate-like carbon sheets within the CSs can provide continuous and fast electron/ion transport channels, accelerating the Li+ transfer kinetics. Moreover, the internal interconnected carbon networks can confine the lithiophilic nanoparticles, preventing them from detaching or aggregating during cycling, and meanwhile offer individual voids to accommodate deposited Li. Thus, both lithiophilic seeds and deposited Li can be well confined in the pomegranate-like structure. Such a dual-confinement effect enables the ZnO@NPCS electrode to exhibit ultralong cycling life for more than 1000 cycles with ultrahigh CE (>99.5 %) without Li dendrites growth, which is further validated by in-situ transmission electron microscopy and phase-field simulations. Therefore, this dual-confinement strategy provides an inspiring insight to design superior Li hosts for developing superior LMBs and can be extended to other battery systems. [ABSTRACT FROM AUTHOR]

Abstract: The δ′ precipitation behavior during retrogression and reaging (RRA) heat treatment in 1420 alloy has been investigated by small angle X-ray scattering (SAXS) method. SAXS results indicate that the transition interfacial layer exists between δ′ phase and matrix in earlier aging and reaging stages. The diffuse phase boundary gradually disappears with the increase of aging and reaging time. The specific inner surface (S p) rapidly decreases during aging to retrogression. The sample of retrogression 5min has a sharply defined phase boundary between δ′ phase and matrix. The gyration radius of the particle decreases. Some larger and smaller δ′ particles coexist in the sample. RRA treatment results in an increase in the volume fraction of δ′ phase particles. [Copyright &y& Elsevier]

Abstract The improvement of comprehensive properties including hardness, toughness, wear, and corrosion resistance in the transition-metal carbides/nitrides (TMC(N)) films, especially avoiding the trade-off between the hardness and toughness, is strongly required for various applications. Herein, we provide a new strategy, by activating solid-state dewetting during layered deposition, to accomplish the self-assembly of ordered TaC@Ta core–shell-like nanocomposite film consisting of TaC nanocrystallines encapsulated with thin pseudocrystal Ta tissues (∼1.5 nm). The novel core−shell-like structure can simultaneously achieve superhardness (∼45.1 GPa) mainly dominated by the Orowan strengthening mechanism and high toughness attributed to the indenter-induced phase transformation from the pseudocrystal to body-centered cubic α-Ta, together with drastically enhanced wear and corrosion resistance. Furthermore, thin pseudocrystal Ta encapsulated layer (∼1.5 nm) in the TaC@Ta core–shell-like structure helps for promoting the formation of lubricious TaO x Magnéli phase during sliding, thereby further dropping the coefficient of friction relative to TaC monolayer. Apparently, solid-state dewetting may provide a new route to construct ordered TMC(N)@TM core–shell-like nanocomposite structure capable of combining superhardness, high toughness, low friction, and superior wear and corrosion resistance. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract The interaction between active materials and conductive additives is complicated but crucial within electrochemical energy storage devices. Here, we first identify that CH 2 groups drive the compositing process, leading to an effective formation of Co-O-C chemical bonding serving as the bridge between reduced graphene oxide(rGO) and hydroxide. Due to the enhanced electron transport, a dramatically improved specific capacity is achieved as high as 1368 F/g for rGO/Co(OH) 2 electrode at a current density of 0.5 A/g. Thus, we provide new insights into graphene/hydroxide compositing mechanism, which has a significant impact on enhancing electron transport for a variety of graphene/hydroxide in energy storage systems. Highlights • CH 2 groups transform into Co-O-C bonds as the bridge between graphene and Co(OH) 2. • rGO/Co(OH) 2 exhibits a highly crystalline feature. • BG/Co(OH) 2 holds more Co3+ ions and Co-O tetrahedral structures. • C-(O-Co) n affords abundant electron transport channels. • A dramatically high specific capacity of 1368 F/g is achieved for rGO/Co(OH) 2. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

(Ba 1− x Nd x ) (Ti 0.97 Mn 0.03 )O 3 (BNTM) ( x  = 0.01, 0.02, 0.04, 0.06) ceramics were prepared using a conventional cold-pressing ceramic technique. The structure, valence state and dielectric properties were investigated using XRD, RS, SEM, TEM, EPR, and dielectric temperature and frequency measurements. XRD, RS analysis coupled with SEM and TEM observations indicate that the samples have a coexistence of tetragonal and hexagonal phase at room temperature as x  ≤ 0.02 and become a single phase in the tetragonal as x  = 0.04 and in the cubic as x  = 0.06 (air-sintered, 1400 °C/12 h). It reveals that Nd 3+ ions can suppress hexagonal phase effectively and benefit the formation of single-phase ceramics. Improvement of dielectric properties is accompanied by the structural evolution. Particularly a cubic ceramic with x  = 0.06, the dielectric-peak temperature is found to shift to room temperature, meeting the EIA Y5V specification with tan δ < 0.04. Up to x = 0.04, the phase transition remains first order. The valence state of Mn ions was analyzed by EPR. It is found that Mn ions transform from high valence (+3 and + 4) to low valence (+2) with the increase of Nd concentration, and all of the Mn ions exist as Mn 2+ when x  = 0.06. The unit cell volume and dielectric-peak temperature of BNTM decrease nonlinearly with increasing x , which can be ascribed to the incorporation of Nd ions and the formation of 2 N d B a · − M n T i ″ donor-acceptor defect complexes. [ABSTRACT FROM AUTHOR]

The development of next-generation programmable metasurfaces urgently requires phase change materials with dielectric-metallic transition (DMT-PCMs). Although DMT-PCMs in the infrared have been reported, DMT-PCMs in the visible spectrum are yet to be designed, limiting the nanophotonic applications of conventional programmable metasurfaces to the infrared band. Herein, we find that stoichiometric germanium monotelluride solid solutions, Ge 1- x M x Te (M = Sn, Sb, Pb, and Bi), have excellent DMT performance throughout the whole visible spectrum, and they can be used as versatile material platforms for fabricating programmable metasurfaces. As a proof-of-concept, the DMT performance of stoichiometric Ge 0.9 Sn 0.1 Te solid solution is significantly superior to that of commonly studied non-stoichiometric PCMs (e.g., Ge 2 Sb 2 Te 5 , Sb 2 Te 3). Through a combination of experiments and first-principle calculations, we demonstrate that the high DMT performance of Ge 0.9 Sn 0.1 Te derives from the unique bonding structure of the crystalline state with non-stoichiometric vacancy-free, high atomic number, and weak Sn-Te bonds, which is not present in conventional PCMs. Furthermore, using ultrashort-pulse lasers, we show that the crystalline Ge 0.9 Sn 0.1 Te can be arbitrarily written, erased, and modified at the subwavelength level. The resonance peaks and colors of the Ge 0.9 Sn 0.1 Te-based grating metasurface can be continuously modulated over the whole visible spectrum. These results suggest that the DMT material platforms can be used to fabricate programmable metasurfaces. Therefore, this work presents a coherent report on the physical origin, material design, and photonic devices of DMT in the visible spectrum, which may extend the applications of programmable metasurfaces from the infrared band to the visible spectrum and inspire more researches. [Display omitted] [ABSTRACT FROM AUTHOR]

Single-atom catalysts have attracted extensive attention due to their unique performances and high atom utilization. However, is single atom always the best? Here we found a reverse case that nickel metaphosphate (NPO) supported nanoparticles (Ru n) is much better than single atoms (Ru s) for all pH hydrogen evolution. The mass activity of Ru n -NPO is 3.8 times higher than that of Ru s -NPO, and 21.4 times higher than that of Pt/C in alkaline media. The results show that Ru nanoparticle possess lower valence state than single atom, providing optimized Ru-H bond strength and suitable hydrogen adsorption free energy. As a novel support, NPO is also essential for firmly anchoring Ru and transporting electrons for optimizing the d -band center, and eventually accelerating the H 2 O dissociation in rate-limiting Volmer step. This work gives Ru-NPO promising potential for practical hydrogen production, and sheds light on the exploration of supported metal catalysts in energy conversion-related fields. [Display omitted] • Nickel metaphosphate (NPO) supported Ru catalyst is developed for all pH HER. • Ru nanoparticles exhibit better HER activity than Ru single atoms. • NPO optimizes the thermodynamic parameter of Ru through metal-support interactions. • The sluggish kinetics of Ru in Volmer step have been speed up. [ABSTRACT FROM AUTHOR]

Ta–Si-C films were deposited by DC magnetron co-sputtering using TaC and Si targets in an Ar-discharge atmosphere. Increasing the current of Si target from 0.0 to 0.5 A led to a continuous increase of Si content from 0.0 to 30.8 at%. The effects of Si content on microstructure were systematically investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). At low Si content (≤ 5.6 at%), Si occupied C vacancies to form a solid solution Ta(C, Si). Further increasing the Si content, some Si atoms bonded with C atoms resulting in the formation of amorphous phase (a-C:Si), and the films presented a nanocomposite structure consisting of solid solution Ta(C, Si) surrounded by a-C:Si matrix. At the highest Si content (30.8 at%), the film exhibited finally X-ray amorphous structures. The hardness ( H ) and fracture toughness ( K f ) were observed to initially increase and then decrease as the Si content was increased. At 5.6 at% Si, the film exhibited a maximum in H (44.9 ± 2.7 GPa) and K f (3.61 ± 0.16 MPa m 1/2 ), which can be ascribed to the formation of a solid solution. On further increasing the Si content, an amorphous phase gradually appeared, leading to a decrease in H and K f . [ABSTRACT FROM AUTHOR]

Nd-doped BaTiO 3 ceramics with Ti vacancy compensation were prepared by a solid-state reaction method, and the lattice structures were identified by XRD and Raman spectra. Samples with light doping possess a tetragonal structure at room temperature, while the cubic phase appeared as the doping content increased. Dielectric properties at low temperature (−100–0 °C) were characterized by the dielectric constant, complex impedance and electric modulus. Colossal dielectric constant and dielectric relaxation processes appeared in all samples. Three electrical responses were observed in the low doping content ceramics, while four appeared in the high doping content ceramics by a combined plot of Z″ and M″. These responses were attributed to the microstructure inhomogeneity, which in turn can be ascribed to charge segregation when the doping content is high. Localization of charge carriers was also observed in all of the ceramics, and the confined carriers preferred to exist in the grain when the doping content was low, while localization would be more significant in grain boundaries with increased dopant. The localization could be ascribed to the formation of defect complexes, which on one hand maintained a high resistivity to the ceramics, and on the other hand, resulted in polarization of the dipoles. Both Maxwell-Wagner polarization and dipole polarization were found to exist in the Nd-doped BaTiO 3 ceramics and were responsible for the colossal dielectric constant and relaxations. The space charge, defect complexes, and microstructure are assumed to be responsible for the change in the dielectric constant and the relaxation mechanism. [ABSTRACT FROM AUTHOR]

A series of TaC/SiC multilayer films with different SiC thicknesses (t SiC ) have been prepared by magnetron sputtering and their microstructure, hardness and toughness investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM) and nanoindentation. Results show that SiC crystallized and grew coherently with TaC layers at low t SiC (≤ 0.8 nm), resulting from the template effect of TaC layers. Maximum hardness and toughness of 46.06 GPa and 4.21 MPa m 1/2 were achieved at t SiC = 0.8 nm with good coherent interface. With further increasing of t SiC , SiC layers partially transformed to an amorphous structure and gradually lost their coherent interface, leading to a rapid drop in hardness and toughness. The crystallization of SiC layers and the coherent growth are required to achieve superhardness and high toughness in the TaC/SiC multilayers. [ABSTRACT FROM AUTHOR]

The high-hardness nature of transition metal nitrides (TMN) has been widely exploited for industrial applications ranging from wear-resistance and cutting tools to scratch-resistant films. To design TMN-based films displaying a further improved toughness and a reduced friction represent urgent challenges. Up to now, creating a nanocomposite structure by introducing a very small content of the metal phase has been considered as a common strategy to enhance hardness and toughness. Herein, we present a new approach to incorporate few solute Ag atoms (∼1.5 at.%) into NbN film to form a Nb-Ag-N solid solution structure, achieving enhanced hardness and toughness, coupled with improved wear-resistance ability and remarkable drop in coefficient of friction (CoF). Hardness and toughness enhancement as well as the tribochemistry actuated by solute Ag have been investigated by combined experimental and density functional theory (DFT) analyses. Results show that the hardness enhancement induced by solute Ag stems from the combination of variation in microstructure and increment in bulk modulus B and C 44 . DFT calculations and electronic structure analyses further reveal that the presence of hybridizations between Ag 5s, 4d orbitals and N p-electrons is responsible for increment in B and C 44 ; furthermore, the appearance of additional Ag e g states contributes to the improved toughness. Additionally, solute Ag can activate self-oxidation by forming Ag 2 O + Nb 2 O 5 at the surface, which is beneficial for the formation of silver niobate (AgNbO 3 ) during the sliding, thereby triggering the falling of the CoF at only 1.5 at.% Ag. Incorporation of few solute Ag atoms into TMN may provide a new strategy to improve the comprehensive properties including hardness, toughness, friction and wear-resistance. [ABSTRACT FROM AUTHOR]

Transition metal nitrides are being widely applied, as durable sensors, semiconductor and superconductor devices, their electrical conductivity and wear resistance having a significant influence on these applications. However, there are few reports about how to improve above properties. In this paper, tantalum was incorporated into hafnium nitride films through Hf 1- x Ta x N y [ x =Ta/(Hf+Ta), y =N/(Hf+Ta)] solid solution. The electrical conductivity and wear resistance of the films were significantly improved, due to the increase of the electron concentration (tantalum has one more valence electron than hafnium) and the increase in H/E and H 3 /E 2 ratios caused by the effect of solid solution hardening, respectively. The highest electrical conductivity of Hf 1- x Ta x N y films is 8.3×10 5 S m −1 , which is 1.7 times and 5.2 times of that of hafnium nitride and tantalum nitride films, respectively. In addition, the lowest wear rate of films is 1.2×10 −6 mm 3 /N m, which is only 10% and 48% of that of hafnium nitride and tantalum nitride films, respectively. These results indicate that alloying with another transition metal is an effective method to improve electrical conductivity and wear resistance of transition metal nitrides. [ABSTRACT FROM AUTHOR]

Nickel decorated vertically aligned graphene sheets (VGSN1) and vertically aligned graphene sheets-graphene shell/nickel core (VGSN2) hybrids have been synthesized by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD). The surface morphology, microstructure and growth mechanisms of VGSN1 and VGSN2 hybrids were investigated. The field emission (FE) studies indicated that the graphene-Ni hybrids delivered better FE performance than pristine graphene (VGS/Si) due to the insert of Ni particles. The influences of the morphologies and structures on FE performance have been revealed. Our approach provides a novel way to fabricate highly efficient graphene-based field emitters for the development of practical electron sources. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon dot assemblies with versatile morphologies are introduced. • Geometrical arrangements and interactions of carbon dot building blocks are considered. • Assembly induces attractive optical properties in supra-(carbon dots). • The underlying mechanisms in photophysical processes of supra-(carbon dots) are discussed. • Applications of supra-(carbon dots) in photothermal conversion and photosensitization are presented. Through non-covalent or covalent assembly of carbon dots (CDs), functional CD assemblies (supra-CDs) with versatile architectures can be created. Among non-covalent forces, various supramolecular interactions can be used for this purpose, including amphiphilic interactions, H-bonding, electrostatic and π–π interactions, and van der Waals forces. Among covalent ones, chemical reactions including coordination interactions and interparticle/intermolecular covalent condensation of CDs result in the formation of supra-CDs. All these different kinds of interactions of CD building blocks have an impact on energy band structures and photophysical and photochemical processes and thus endow supra-CDs with intriguing optical properties. We review the recently emerged research field of supra-CDs in terms of their synthesis, morphologies, assembly-induced optical properties such as emission quenching or enhancement, occurrence of polarized emission and optical chirality, and underlying mechanisms. Their specific advantages for applications such as photothermal conversion and photodynamic therapy are presented, in order to inspire further development of supra-CDs. [ABSTRACT FROM AUTHOR]

Boron carbide (B4C) coating on diamond particle is synthesized by heating diamond particles in a powder mix of H3BO3 and B in Ar atmosphere. The composition, bond state and coverage fraction of boron carbide coating on diamond particles are investigated. The boron carbide coating favors to grow on diamond (100) surface rather than on diamond (111) surface. Cu matrix composites reinforced with B4C-coated diamond particles were made by powder metallurgy. The addition of B4C coating gave rise to a dense composite. The influence of B4C coating on both tensile strength and thermal conductivity of the composite were investigated. When the B4C fully covered on diamond particles, the composite exhibited a greatly increase in tensile strength (115 MPa) which was much higher than that for uncoated-diamond/Cu (60 MPa) composites. Meanwhile, a high thermal conductivity of 687 W/mK was achieved in the B4C-coated-diamond/Cu composites. [ABSTRACT FROM AUTHOR]

In recent years, shape control has received the most attention in the exploration of Pd nanocrystals (NCs). However, exploring an efficient approach for the systematic production of Pd NCs under similar reaction conditions still presents a significant challenge, which is significantly important to clearly explain the effectiveness of morphology on the catalytic activity of Pd NCs. We designed and accomplished a facile strategy for the morphology transformation between Pd nanosheets and Pd nanotetrahedra by simply controlling the reaction temperature. A growth mechanism was proposed based on TEM images of the time-dependent morphology evolution. The Pd nanosheets and Pd nanotetrahedra exhibit higher activity for the methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) compared with the benchmark Pd/C catalysts, and their activities are dependent on the morphology. In particular, Pd nanosheets show an increased activity by 3.81 (MOR) and 2.86 (ORR) times due to their large specific surface area and exposed facets. [ABSTRACT FROM AUTHOR]

N, S co-doped graphene quantum dots (N, S-GQDs) -reduced graphene oxide- (rGO) -TiO 2 nanotubes (TiO 2 NT) composites were prepared by a facile alkaline hydrothermal reaction and physical stirring process. The apparent rate constant of the N, S-GQDs+10%rGO + TiO 2 NT composite, exhibiting the highest photodegradation efficiency, is 1.8 times and 16.3 times higher than those of 10%rGO + TiO 2 NT and pure TiO 2 NT, respectively, for the degradation of methyl orange (MO) under visible light irradiation (λ > 400 nm). Our work could provide new insights into the fabrication of GQDs-semiconductor composites as high performance photocatalysts and broaden the range of doped GQDs widely used for environmental protection. [ABSTRACT FROM AUTHOR]

Batteries are key components in electric vehicles and energy storage systems. To estimate a battery's state of charge, monitor its state of health, and formulate a balanced strategy, a battery model that requires a shorter and less costly study period than a real battery is established. This paper aims to describe a single-particle model of a lithium-ion battery that has a simple structure, can be embedded in simulation software for online applications, and provides a high-accuracy characterization of the dynamics. The single-particle model, which is described by a set of partial differential equations, is a simplified electrochemical model that characterizes the dynamic voltage response. A procedure for reducing the model based on the three-parameter polynomial approximation and the volume-average integration method is proposed to simplify the partial differential equations of the single-particle model. Identifying the parameters in the battery model is the key problem. The convergent bacterial foraging optimization algorithm with a short computation time is adopted for identifying the electrochemical parameters, including the active surface areas of the electrodes, the diffusion coefficients of the lithium ions in the solid phase, and the reaction rate constants. Then, the single-particle model of a lithium-ion battery is set up in MATLAB and Simulink. Finally, the precision of the single-particle model is verified by comparing the terminal voltages of the battery and the model. The results show that the single-particle model of a lithium-ion battery is very accurate and simple, thus verifying the reliability of the parameter identification process. Graphical abstract: [ABSTRACT FROM AUTHOR]