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Core/shell quantum dots (QDs) have been extensively studied, yet their optical properties widely vary among studies. Such variation may arise from the variation in interfacial structures induced by the subtle difference in each synthetic procedure. Here, we studied the interfacial structures of CdSe/ZnS QDs using the time-of-flight medium energy ion-scattering spectroscopy (TOF-MEIS), which offers the radial elemental distributions as well as the overall elemental compositions of QDs. The TOF-MEIS spectra provided strong evidence for the existence of an alloyed layer at the interface between CdSe and ZnS in typical CdSe/ZnS QDs. On the basis of the emission and absorption spectra of QDs sampled during the synthesis, we conclude that such interfacial alloying is caused by the dissolution of CdSe seeds during the synthesis steps. Such a dissolution mechanism is further corroborated by the observation that the ligand environment of solvent (X or L type) leads to different shapes of interfaces.

The FCC structured CoCrFeMnNi high entropy alloy (HEA) has attracted great attention due to its excellent ductility and strain hardening ability, but the lowest yield strength is insufficient for structural applications. To achieve high strength and ductility, we developed a new strategy called harmonic structure (HS) consisting of soft coarse and hard fine grains via controlled mechanical milling time. The SEM and EBSD microscopic characterizations reveal that the formation of HS from surface to the interior of powder is due to a difference in the degree of plastic deformation. The hardness of HS HEAs increased with increasing distance from center to surface regions due to a reduction in grain size. Compared with the homogeneous HEA, the yield strength of HS HEAs increased from 370 MPa to 730 MPa and 760 MPa due to grain boundary strengthening, dislocation strengthening, and twin boundary strengthening effects. While HS HEAs exhibited enhanced strain hardening ability due to gradient structure with their mechanical incompatibility provide back stress strengthening. Furthermore, the compressive deformation behavior of homogeneous and HS HEAs was analyzed by microstructural evolution.

Thermoelectric devices are environmentally friendly renewable energy sources that use waste heat to generate electricity. So far, p-type Bi–Sb–Te-based alloys with high thermoelectric properties were fabricated using low-dimensional and single growth methods as small-scale, laboratory-grown samples. However, large-scale fabrication processes are required for commercial applications of thermoelectric devices. In this work, large amounts (2–3 kg) of p-type 20%Bi2Te3–80%Sb2Te3 alloy powders were fabricated using the gas atomization (GA) process under an inert gas atmosphere. Subsequently, a large-scale sample, 64 mm thick and 25 mm in diameter, was consolidated from the as-fabricated GA powders using spark plasma sintering at 673 K. The homogeneity of the microstructure, density, thermoelectric properties, and mechanical properties of the high-thickness sintered bulk were systematically investigated at various positions. The EBSD texture analysis revealed that an almost similar microstructure existed in all positions of the bulk sample, which was comprised of a mixture of coarse grains and fine grains randomly distributed throughout the matrix. The peak electrical conductivity of 1100 Ω−1 cm−1 was obtained from the top position of the thick sample, which had a relatively higher carrier mobility. The maximum power factor of 3.96 mW/mK2 was achieved by the top part of the specimen, because of its higher electrical conductivity. The lowest thermal conductivity of 0.964 W/mK at 350 K was obtained from the bottom part of the specimen. As a result, the maximum figure of merit, ZT of 1.25 was achieved in the bottom position of the high-thickness sample. Homogeneous (within 5% of variation) thermoelectric transport properties were observed throughout the fabricated high-thickness sintered sample, regardless of position.

In the present study, Cu54Ni6Zr22Ti18 bulk metallic glass composites were developed by spark plasma sintering(SPS) using gas atomized Cu54Ni6Zr22Ti18 metallic glass powders and Ta powders. Metallic glass composites with Ta phase were fabricated by SPS. The successful consolidation of Cu54Ni6Zr22Ti18 metallic glass matrix composites with the Ta phase was achieved through the strong bonding due to the plastic deformation of the Ta powder and the super-plastic behavior of the metallic glass powder in the supercooled liquid state during SPS. The deformed Ta phases were well distributed in the Cu54Ni6Zr22Ti18 metallic glass matrix. The compressive fracture strength and total strain were 1770 Mpa and 10.2%, respectively, for the Cu54Ni6Zr22Ti18 bulk metallic glass composite with 40 wt% Ta phases. The uniformly dispersed deformed Ta phase in the Cu54Ni6Zr22Ti18 metallic glass matrix effectively impedes the propagation of the first shear band and generates a second shear band, causing a crossing of the shear bands, resulting in an improvement in plastic strain. This increase in plastic deformation is related to the fact that the deformed Ta phase, uniformly distributed in the Cu54Ni6Zr22Ti18 metallic glass matrix, acts as a source of shear bands and at the same time effectively suppresses the movement of the shear bands, dispersing the stress and causing wide plastic deformation.

The fabrication of high-quality metallic powders has been attracted considerable attention in terms of producing advanced materials through additive manufacturing (AM) technology. The efficiency of...

In this article, we propose a novel real-time threshold voltage ( $V_{th}$ ) compensation method for AM-OLED display. The proposed method predicts $V_{th}$ shift of driving thin-film transistors (TFTs) based on the equation derived from the sensing line charging with TFT’s drain current. The prediction equation requires two consecutive source node voltages to consider the mobility variation, and only takes hundreds of microseconds to predict $V_{th}$ shift. It is short enough to monitor the real-time $V_{th}$ degradation, since the prediction can be carried out during the vertical blank time. Also, very high prediction accuracy was confirmed through Smart SPICE simulation. We simulated severe mobility variation and $V_{th}$ shift circumstances, and the simulation results showed that the prediction error was less than one just noticeable difference (JND) margin though out all gray levels. We expect that the proposed method can achieve more accurate and faster real-time $V_{th}$ degradation compensation for high resolution and large-sized OLED displays than conventional one.

BACKGROUND: In patients with rheumatoid arthritis (RA), some problems might occur in fracture healing; however, clinical evidence is limited. Therefore, we compared the time to union and complication rate of femoral fractures between RA and non-RA patients. MATERIALS AND METHODS: This study included 42 RA patients who underwent osteosynthesis for femoral trochanter or shaft fracture. For comparison with the RA group, 126 non-RA patients were selected as a control group. The RA group was divided into the trochanteric (RA group I) and shaft fracture group (RA group II) for comparison with each control group (control groups I and II). We analyzed risk factors for nonunion or delayed union and divided patients according to whether atypical or ordinary fracture in shaft fracture. RESULTS: Time to union (p = 0.823) and complication rate (p = 0.440) did not differ significantly between RA group I and control group I. A significantly longer time to union (p = 0.001) and higher nonunion rate (p = 0.013) were observed in RA group II compared with control group II. The presence of RA (p = 0.040) and atypical femoral fracture (p = 0.006) were significant risk factors for nonunion or delayed union. CONCLUSIONS: The high prevalence of atypical femoral fracture among the femur shaft fractures in the RA patients was considered a significant risk factor for nonunion and delayed union.

The purpose of this study was to investigate the incidence of symptomatic venous thromboembolism (VTE) after chemoprophylaxis in patients with pelvic and lower-extremity fractures, and to identify risk factors for VTEs in this subgroup of patients. To detect VTE, multi-detector computed tomography (CT) angiography was performed. Of 363 patients assessed, the incidence of symptomatic VTE was 12.4% (45 patients), and the incidence of symptomatic PE was 5.2% (19 patients). For the risk-factor analysis, a higher Charlson comorbidity index (p = 0.037), and a history of external fixator application (p = 0.007) were associated with increased VTE risk. Among patients who had VTE, male sex (p = 0.017), and above-the-knee fractures (p = 0.035) were associated with increased pulmonary embolism (PE) risk. In conclusions, the incidence of VTE in post-traumatic patients is not low after chemoprophylaxis. Risk factors for VTE and PE are different among patients with pelvic and lower-extremity fractures.

Based on the dimensions and thresholds of power and power density of a commercial shock absorber in the Korando car (an SUV branch), a single-phase 8-slot 8-pole tubular permanent magnet (PM) machine was designed and fabricated. The main focus of this paper is on the increase of output power in a given space and reduction of the volume. This is successfully solved using a novel structure for PM and considering a number of slot–pole combinations. Furthermore, a multiobjective optimization is performed to find the tradeoff between various objectives. The experimental results reveal that the proposed machine can possibly regenerate a maximum of 339.95 W and an average of 96.67 W in terms of its output power. Considering the active volume, which includes PM, iron core, pure copper, and an electromagnetic air gap, the estimated maximum and average power density are 0.311 and 0.087 W/cm3, respectively. Despite these satisfactory results, one of the major drawbacks to exploiting this machine is its high electromagnetic force, which causes negative effects on safety and driving comfort. With the aim to commercialize the proposed device, further work will be concentrated on the reduction of electromagnetic force and on performance of the road tests.

Histological and cytological observations of the human anterior cruciate ligament (ACL) had been described, but the differentiation potency based on their location is still unknown. To determine and compare proliferation and differentiation potential of cells derived from distal and middle thirds of the ACL remnant, ACL remnant was initially marked at the distal third (within 10 mm from the tibial insertion) and middle third (between 10–20 mm from the tibial insertion) and then dissected. Both the middle and distal third regions of ACL remnant were analyzed using CD34+ cell counting. Cell proliferation rate did not differ in both middle and distal third regions of ACL remnant, but they showed different characteristics in cell differentiation depending on their location. The distal third region of the ACL remnant had a tendency for chondrogenic differentiation with higher expression of CD34+ cells. On the other hand, the middle third region of ACL remnant had a strong tendency for osteogenic and ligamentous differentiation. Characteristics of the ACL remnant tissues should be considered when performing remnant-preserving or harvesting ACL remnants for tissue engineering.

Singlet oxygen is a toxic chemical but powerful oxidant, exploited in many chemical and biological applications. However, the lifetime of singlet oxygen in air under atmospheric conditions is yet to be known. This has limited safe usage of singlet oxygen in air, despite being a strong antimicrobial agent with the unique property of relaxing to breathable oxygen after serving its purpose. Here, we solve this long-standing problem by combining experimental and theoretical research efforts; we generate singlet oxygen using a photosensitizer at a local source and monitor the time-dependent extent of singlet oxygen reaction with probe molecules at a detector, precisely controlling the detector distance from the source. To explain our experimental results, we employ a theoretical model that fully accounts for singlet oxygen diffusion, radiative and nonradiative relaxations, and the bimolecular reaction with probe molecules at the detector. For all cases investigated, our model, with only two adjustable parameters, provides an excellent quantitative explanation of the experiment. From this analysis, we extract the lifetime of singlet oxygen in the air to be 2.80 s at 23 °C under 1 atm, during which time singlet oxygen diffuses about 0.992 cm. The correctness of this estimation is confirmed by a simple mean-first-passage time analysis of the maximum distance singlet oxygen can reach from the source. We also confirm the sterilization effects of singlet oxygen for distances up to 0.6-0.8 cm, depending on the bacteria strain in question, between the bacteria and the singlet oxygen source.

This paper proposes an anti-slip traction control for electric vehicle based on torque observer. The proposed traction control consist of direct torque control and unknown input observer. The direct torque control has the performance of fast response and accuracy torque control and the unknown input observer is a proper scheme to estimate a load torque which depends on the unknown road condition. The torque command of a traction motor is compensated according to a load torque estimated by an unknown input observer. The feasibility and validity of the proposed scheme were proven by simulation results.

This paper investigates an energy-harvesting system that uses of vibration energy at a shock absorber for electric vehicles. This system mainly comprises a linear electromagnetic generator and synchronous buck converter. To obtain the electrical energy through a linear electromagnetic generator, the perturb and observe maximum power point tracking (P&O MPPT) scheme is applied at the converter. The power converter circuit is designed with a diode rectifier and synchronous buck converter. The generated electric power is able to transmit to the battery and the damping force of the shock absorber is adjusted by the controlled current of generator. The linear electromagnetic generator was designed as a single phase eight-slot eight-pole tubular permanent magnet machine. The performance of the proposed energy-harvesting system was verified through simulations and experiments.

A series of hollow structured (Sn,Ti)O2 solid-solutions with varying Sn content are prepared by a soft template method. Not only a complete incorporation of Sn4+ into TiO2 lattice but also a Sn O Ti bonding is identified, and morphologically, interconnected pores are confirmed between the hollow (Sn,Ti)O2 solid-solution nanoparticles. In battery performance, along with enhanced lithium storage, consistent utilization of Sn in voluminous alloying/de-alloying reactions is demonstrated. Beyond the TiO2 typically known as a stable anode material, the superior capacity retention of solid-solution rather containing Sn shows that the Sn O Ti bonding in (Sn,Ti)O2 solid-solution leads to the synergy effect of increased energy density from Sn and stable capacity retention from Ti.

The effect of precipitate structures of a B2-NiAl/L21-Ni2TiAl hierarchical precipitate-strengthened ferritic alloy on the precipitate/matrix interface, elastic strain, and creep resistance has been investigated by systematic heat-treatments and creep experiments. The experimental results reveal that the highest creep strength was achieved in a heat-treated sample containing the largest coherent precipitate with fine internal networks, whereas the semi-coherent precipitate results in a sharp drop of the creep strength. It was found that the strong elastic strain field, affected by the internal structure within the precipitate, plays a crucial role in improving the creep resistance.

We developed a gradient quantum dot (QD)@polyvinylpyrrolidone (PVP)-silica composite as a spectral converter to improve light harvesting of the photoactive layer in organic photovoltaic (OPV) devices. The spectral converter prepared by a simple sol–gel method served as a luminescent down-shifting (LDS) layer that absorbed ultraviolet and emitted visible light. Re-emitted light energy from the LDS layer appeared within the absorption range of the photoactive donor material of P3HT in the OPV devices. We investigated how the light harvesting ability was affected by the concentration of QD@PVP and the thickness of the LDS layer. The OPV devices with the LDS layer showed increased power conversion efficiency (PCE) from 3.38% to 3.68% compared to pristine OPV devices due to improved incident light transmittance and increased light harvesting.

We report on Qualcomm® Snapdragon™ 765 mobile Platform and world's first integrated 5G platform supporting both mmWave and sub-6 using industry-leading 7nm EUV FinFET technology. Snapdragon 765 unites 5G and AI to power select premium-tier experiences on a global scale. Snapdragon 765 exhibits 20% improvement in performance and 35% lower power consumption over its predecessor Snapdragon 730 (8nm FinFET) thanks to device performance boost with new technology integration feature (MDB), power-perf efficient design architecture enabled by dual poly pitch process, and low voltage logic/memory operation through process-design co-development. Further process-design co-optimization reduces CPU Vmin by 80mV, enabling premium-tier performance experience with integrated 5G and AI mobile SOC platform.

Background: In Daegu, Korea, a coronavirus disease 2019 (COVID-19) outbreak occurred within a religious group. Because the hospitals in Daegu cannot afford to admit all the infected subjects with COVID-19, the Korean government has turned private dormitories and public organization-run facilities into living and treatment support centers (LTSCs) for isolation of subjects with or without mild symptoms. Methods: Data of 130 COVID-19 patients with or without mild symptoms were collected from the Jecheon LTSCs. Questionnaires about their symptoms were obtained twice per day from March 10, 2020, to April 3, 2020. Findings: A total of five subjects were transferred to general hospitals. Two cases were clearly related to COVID-19. The percentage of asymptomatic cases tended to increase over time from a minimum of 56% to a maximum of 80%. Except for the five subjects who were transferred to hospitals, asymptomatic and mildly symptomatic subjects with COVID-19 did not require specific medical treatment during the LTSC admission period. Interpretation: Subjects with COVID-19 can carry the virus for a long time. even if they are asymptomatic or mildly symptomatic, and LTSC is one good measure to prevent the spread of COVID-19 by isolating asymptomatic or mildly symptomatic subjects when a large outbreak occurs. Funding Statement: There was no funding source for this study. Declaration of Interests: The authors declare that they have no competing interests relevant to this study. Ethics Approval Statement: The study protocol was approved by the Institutional Review Board (IRB) of National Health Insurance Ilsan Hospital (IRB number:2020-04-009). The requirement for written informed consent from patients was waived due to the retrospective nature of the study and its impracticability.

AIM Most heel pain occurs at the posterior or plantar aspect, where main entheses of the heel are located. However, simple radiographs as basic work-up tools, their features based on their association with local symptoms in the heel in ankylosing spondylitis (AS) patients, have rarely been described. METHOD Forty patients with AS and unilateral heel pain were enrolled to evaluate radiographic differences between symptomatic and asymptomatic heels. The two groups were assessed according to symptom location: posterior (group PS) or plantar (group PL). Typical abnormalities in bone and/or soft tissue on the heel due to inflammation were compared. RESULTS In group PS (20 cases), 19 (95%) symptomatic feet and 7 (35%) asymptomatic feet showed abnormal findings on the posterior heel and symptomatic feet showed 6 (30%) plantar abnormalities. Erosion of the posterior calcaneal tuberosity, obliteration of the retrocalcaneal recess (RR), and swelling shadows with increased thickness on posterior soft tissue were observed more frequently and significantly in symptomatic feet in group PS (P

Luminescent hexagonal dominant copper indium sulphide (h-dominant CIS) quantum dots (QDs) by precursor-injection of mixed metal-dialkyldithiocarbamate precursors. Owing to the different reactivity of the precursors, this method allowed the CIS QDs to grow while retaining the crystallinity of the hexagonal nucleus. The photoluminescence (PL) spectra exhibited dual emission (600–700 nm red emission and 700–800 nm NIR emission) resulting from the combined contributions of the hexagonal (wurtzite) h-CIS and tetragonal (chalcopyrite) t-CIS QDs, i.e. the NIR and red emissions were due to the h-CIS QDs and coexisting t-CIS QDs (weight ratio of h-CIS/t-CIS ~ 10), respectively. The PL intensities of the h-CIS as well as t-CIS QDs were enhanced by post-synthetic heat treatment; the t-CIS QDs were particularly sensitive to the heat treatment. By separating h-CIS and t-CIS successfully, it was demonstrated that this phenomenon was not affected by size and composition but by the donor-acceptor pair states and defect concentration originating from their crystal structure. The h-dominant CIS QDs in this work provide a new technique to control the optical property of Cu-In-S ternary NCs.

To evaluate the prevalence of medial collateral ligament (MCL) injury of the knee among ankle-fracture patients and to determine the risk factors associated with MCL injury in this patient group. 303 patients (303 affected ankles) who underwent surgical treatment for an ankle fracture were assessed. Supination versus pronation injury, Danis-Weber classification, age, sex, body mass index (BMI), limb dominance, and mechanism of injury were reviewed to identify factors related to MCL injury. Prevalence of MCL injury of the knee among the total number of patients with an ankle fracture was 3.96% (12 out of 303 injuries). Multivariable logistic and linear regression analysis with adjustment of possible confounding factors confirmed that female sex and pronation injury were associated significantly (p

This paper reports unique highly porous carbon-coated Si nanoparticles with canyon-like surfaces (cpSi@C) prepared by pseudomorphic transformation of wrinkled silica nanoparticles (WSNs) via magnesiothermic reduction and subsequent pyrolytic deposition of carbon. The pseudomorphic transformation of soft-template-based WSNs with large pore dimensions provides Si nanoparticles with additional porosity owing to their unique canyon-like surface structure. This degree of porosity is not achievable using conventional soft-template-derived porous SiO2 materials owing to their smaller pore dimensions. The free volume space in the cpSi@C particles is 419% of their Si volume, which is sufficient to fully accommodate Si volume expansion during cycling. Furthermore, the conformal carbon coating allows cpSi@C to enhance its electrical conductivity. cpSi@C exhibits a high specific charge capacity of 822 mA h g−1 after 200 cycles at a current density of 0.5 A g−1, which is 59.1% of the initial charge capacity. A comparative study with respect to other porous Si-based materials clearly revealed that the unique canyon-like structure synthesized in this study, with its additional pore volume and smaller Si dimensions, exhibits enhanced electrochemical performance.

Refractory high-entropy alloys (RHEAs) show a great potential as structural materials due to their remarkable properties, such as high strength and thermal stability. Despite these advantages, the RHEAs still suffer from the limited ductility at room temperature. To overcome the strength-ductility trade-off, the new RHEA design strategy, transformation-induced plasticity (TRIP) HEAs, have been developed by applying metastability-engineering approach. With the newly developed RHEAs design strategy, we designed metastable RHEAs, TiZrHfVxNbxTax (x = 1.0, 0.5 and 0.1) with decrease of the β-stabilizing elements (V, Nb, and Ta) to promote the transformation-induced ductility and work-hardening capability. The proper addition of the β-stabilizing elements (V, Nb, and Ta) into the ternary equi-molar TiZrHf alloy (TiZrHfV0.1Nb0.1Ta0.1) leads to stress/strain-induced phase transformation from the body-centered cubic (BCC) to hexagonal-close-packed (HCP) α′ and/or orthorhombic α″ phases. Detailed studies on the phase transformation sequence during the deformation were carried out using X-ray diffraction (XRD), electron back-scattered diffraction (EBSD), and transmission-electron microscope (TEM), which revealed the stepwise phase transformation that is responsible for the strong strain hardening behavior. Furthermore, we further suggested the new transformation-induced-plasticity (TRIP) HEA design strategy, applying the Bo-Md approach.

In the background of enhancing thermoelectric (TE) figure of merit of solid-state materials, the introduction of porous structure can significantly decrease lattice thermal conductivity by intensifying phonon scattering at the inhomogeneous microscale pores. Herein, we developed a porous structure in Cu0.07Bi0.5Sb1.5Te3 compounds by utilizing PVA as the pore former, and systematically studied its effect on thermoelectric properties. The results revealed that the reduction in thermal conductivity (~28%) was greater than the decrease in electrical conductivity (~17%) with increasing porosity, indicating long-wavelength phonon scattering was enhanced at micro-scale pores. Consequently, a peak zT of 1.342 at 400 K, and a zTavg of 1.254 in the temperature range of 300–500 K and an ηmax of ~9.4% at ΔT = 200 K were achieved in the porous sample (10.58%), which all are higher than that of dense sample. The hardness and compressive strength of the porous samples were significantly higher than commercial zone melting ingots. The proposed methodology is a cost-effective and efficient way of producing high-performance TE devices with good mechanical stability for real life practical applications.

Shin-Woo Ha,1 Jin-Kyu Lee,2 George R Beck Jr1,3,4 1Division of Endocrinology, Department of Medicine, Emory University, Atlanta, GA, USA; 2Department of Chemistry, Seoul National University, Seoul, South Korea; 3The Atlanta Department of Veterans Affairs Medical Center, Decatur, 4The Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA Abstract: To date, delivery of light-emitting diode (LED)-activated compounds to cells and tissue remains a challenge. Silica-based materials possess good biocompatibility and have advantages of control of size and shape. Fluorescent silica nanoparticles (NPs) have been synthesized and used for applications such as cell tracking and tumor identification. Here, we report the synthesis and optimization of fluorescent silica NPs, which incorporate a naphthalimide dye with triethoxysilanes that are excited by the blue LED wavelength (LEDex NPs). The NPs can be imaged in the 420–470nm wavelength, demonstrate a high quantum yield, are stable in a range of pH, and are taken into the cells. Therefore, these NPs represent a novel imaging technology for biomedical applications. Keywords: naphthalimide, imaging, bone marrow stromal cell migration, reduced toxicity&nbsp

Recently, quantum dots (QDs) have been successfully developed as efficient color converters for light-emitting diodes (LEDs) display due to excellent optical properties of QDs. Herein, we demonstrate a new approach to form metal oxide layers (or metal oxide coating) on the exterior surface of gradient alloy QDs (the most advanced chemical architecture QDs developed thus far wherein the lattice parameter from the core to shell is changing in a gradient fashion) in order to improve the photochemical stability and photoluminescence efficiency. The resulting CdO-treated QDs are incorporated into polymer matrix films to fabricate a backlight unit as a part of display panel wherein CdO-treated gradient alloy QDs are utilized as color converters upon the blue-LED excitation. The fabricated 9.7 in. iPad 2 tablet liquid crystal display panel exhibited an excellent uniformity in terms of CIE chromaticity, luminance, and bright variation and superb durability test results (maintenance of ca. 110% brightness compared to initial value even after 3 weeks of operation).

Coherent precipitates hardening is currently emerging strengthening mechanism of the various high entropy alloys (HEAs). Recently, CrMnFeCoNiAlx HEAs have been studied to show a phase transition from face-centered-cubic (FCC) to body-centered-cubic (BCC) and formation of coherent precipitates (B2-NiAl) within the BCC matrix. The coherent precipitates in the CrMnFeCoNiAlx alloys could contribute to increase the strength but lead to considerable reduction of the ductility. The present work systematically investigated a series of CrMnFeCoNiAl0.5Tix alloys to further improve the strength and plasticity, as compared to the previously reported CrMnFeCoNiAlx HEAs. As a result, an increase of Ti addition leads to the phase transition from FCC to BCC and formation of lamellar structure and hierarchical precipitates reinforced by B2-NiAl and L21-Ni2TiAl phases. Excellent mechanical properties were achieved from CrMnFeCoNiAl0.5Ti0.1 and CrMnFeCoNiAl0.5Ti0.2 alloys. The mechanical properties of the CrMnFeCoNiAl0.5Tix alloys were discussed via theoretical strengthening mechanisms.

In this research, polycrystalline p-type Bi0.5Sb1.5Te3 (BST)/x-wt% graphene (x = 0, 0.05, 0.1 and 0.2 wt%) composite bulks were fabricated to systematically investigate the effect of graphene content on thermoelectric, as well as magnetic and mechanical properties. The peaks corresponding to the D, G and 2D bands of graphene were clearly identified with Raman spectroscopy, and revealed that graphene was well dispersed in the BST matrix. The bulk fracture surfaces displayed randomly distributed grains and a progressive decrease in grain size, with increasing graphene content in the composite samples. A dramatic reduction in thermal conductivity of about 10%, and 12% was achieved for the 0.1, and 0.2 wt% graphene dispersed Bi0.5Sb1.5Te3 samples, respectively, due to the strong scattering of phonons at interfaces and fine grain boundaries. Thanks to the adequate power factor and the reduction in thermal conductivity by the incorporated graphene, the 0.1 wt% graphene dispersed Bi0.5Sb1.5Te3 sample showed the highest ZT value among all samples. Interestingly, a transformation from diamagnetic to para/ferro magnetic properties was observed after graphene incorporation, using magnetic hysteresis loops. Vickers hardness was also greatly improved, from 84.1 Hv to 103.8 Hv, and compressive strength was also increased. It was concluded that enhanced mechanical properties of the Bi0.5Sb1.5Te3 alloys was due to the strengthening effect of hierarchically structured graphene and reduced grain size.

The analyses of phase composition, microstructure and the mechanical properties were conducted for as-cast TaxAl0.7CoCrFeNi2.1 (x = 0.3, 0.5, 0.6 and 0.7) eutectic high entropy composites (EHECs). With the x value increases from 0.3 to 0.6, the phases of dendrite changed from L12 to B2 and volume fraction of ultrafine-eutectic matrix consisting of Face-centered cubic and Laves phases increased. When x = 0.7, the Laves phase appears as the primary dendrite and the matrix region changed into the bimodal eutectic structure (L12 + Laves and B2 + Laves). Thermo-physical parameters could be used for understanding phase formation in EHECs. Experimental and theoretical comparison using thermo-physical parameters shows a reasonable consistency. Depending on the microstructural variation, the yield strength increased from 1304 MPa (x = 0.3) to 2154 MPa (x = 0.6) and plasticity decreased from 17% (x = 0.5) to 4% (x = 0.6). In order to understand the nano-to-micronscale deformation mechanisms depending on the microstructural variations, the systematic investigations of post-deformed samples (x = 0.5 and 0.6) were carried out by multi-scale SEM, TEM, and AFM analyses.

Recently, it has been clearly elucidated that nanostructured Si-based composites hybridized with protective and conductive materials can present enhanced electrochemical performance as anodes for Li-ion batteries (LIBs). One of remaining issues is to develop a sustainable and economic method to synthesize these composites on a large scale for industrial applications. Herein, we introduce a modified magnesiothermic reaction route to prepare the aforementioned Si-based composite electrodes using sea-sand derived Mg 2 Si as a reactive precursor. Owing to its reducibility and lability, Mg 2 Si can readily reduce group IVA oxides, such as Na 2 CO 3 , SiO 2 , GeO 2 , and SnO 2 , resulting in macroporous Si surrounded by the reduced forms of the counter reactants (C, Si, Ge, and Sn, respectively), some of which can be electrochemically attractive. Notably, the porous Si-based composite can be synthesized by a simple solid state reaction, so simplicity and scalability can be obtained. Also, the sea sand precursor is naturally–abundant; hence this process can be cost-effective, scalable, and sustainable. Porous Si@C composite can be synthesized from the modified magnesiothermic reaction using a sea sand-derived Mg 2 Si precursor, showing a specific capacity of 1000 mAh/g at 200th cycle. Potentially this process can be used for practical synthesis of Si-based composites.