Hollow ceramic microspheres (HCMs) have widespread applications in aerospace and electronic areas owing to their multiple merits such as low density, low thermal conductivity, oxidation, and ...high‐temperature resistance. In this work, monodispersed HCMs were fabricated based on preceramic polymers and the pulse‐controlled coaxial injection approach. The size and shell morphology of hollow ceramic spheres can be flexibly tailored by adjusting the diameters of coaxial needles, and the composition and flow rates of inner and outer liquids. As‐obtained HCMs were comprised of ultrafine nanocrystals of ZrO2, SiO2, ZrC, and SiC, which can enhance the interfacial polarization effect. Through optimization of microstructure and composition, the electromagnetic shielding performance of HCMs reached up to 45 dB in the frequency range of 12–18 GHz. This work demonstrates a facile and general method for the fabrication of monodispersed HCMs.
This work demonstrates a facile and general method for the fabrication of monodispersed hollow ceramic microspheres with precise control of size and shell thickness and their potential applications for electromagnetic shielding materials.
Although various catalytic materials have emerged for hydrogen evolution reaction (HER), it remains crucial to develop intrinsically effective catalysts with minimum uses of expensive and scarce ...precious metals. Metallic glasses (MGs) or amorphous alloys show up as attractive HER catalysts, but have so far limited to material forms and compositions that result in high precious‐metal loadings. Here, an Ir25Ni33Ta42 MG nanofilm exhibiting high intrinsic activity and superior stability at an ultralow Ir loading of 8.14 µg cm−2 for HER in 0.5 m H2SO4 is reported. With an overpotential of 99 mV for a current density of 10 mA cm−2, a small Tafel slope of 35 mV dec−1, and high turnover frequencies of 1.76 and 19.3 H2 s−1 at 50 and 100 mV overpotentials, the glassy film is among the most intrinsically active HER catalysts, outcompetes any reported MG, representative sulfides, and phosphides, and compares favorably with other precious‐metal‐containing catalysts. The outstanding HER performance of the Ir25Ni33Ta42 MG film is attributed to the synergistic effect of the novel alloy system and amorphous structure, which may inspire the development of multicomponent alloys for heterogeneous catalysis.
An extremely flat low‐iridium‐content Ir25Ni33Ta42 metallic glass film with an ultralow Ir loading is presented as an intrinsically active and highly stable catalyst for the hydrogen evolution reaction (HER) in acids. This work provides a novel alloy system for HER in acids, and is helpful for the development of heterogeneous catalysts in multicomponent alloys.
Lung cancer is the most commonly diagnosed cancer worldwide, and metastasis in lung cancer is the leading cause of cancer‐related deaths. Thus, understanding the mechanism of lung cancer metastasis ...will improve the diagnosis and treatment of lung cancer patients. Herein, we found that expression of cluster of differentiation 109 (CD109) was correlated with the invasive and metastatic capacities of lung adenocarcinoma cells. CD109 is upregulated in tumorous tissues, and CD109 overexpression was associated with tumor progression, distant metastasis, and a poor prognosis in patient with lung adenocarcinoma. Mechanistically, expression of CD109 regulates protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling via its association with the epidermal growth factor receptor (EGFR). Inhibition of CD109 decreases EGFR phosphorylation, diminishes EGF‐elicited activation of AKT/mTOR, and sensitizes tumor cells to an EGFR inhibitor. Taken together, our results show that CD109 is a potential diagnostic and therapeutic target in lung cancer patients.
CD109 promotes lung cancer metastasis through promoting EGFR‐AKT‐mTOR signaling and CD109 is an independent prognostic marker for lung adenocarcinoma.
Income-based energy poverty metrics ignore people's behavior patterns, particularly reducing energy consumption to limit financial stress. We investigate energy-limiting behavior in low-income ...households using a residential electricity consumption dataset. We first determine the outdoor temperature at which households start using cooling systems, the inflection temperature. Our relative energy poverty metric, the energy equity gap, is defined as the difference in the inflection temperatures between low and high-income groups. In our study region, we estimate the energy equity gap to be between 4.7-7.5 °F (2.6-4.2 °C). Within a sample of 4577 households, we found 86 energy-poor and 214 energy-insecure households. In contrast, the income-based energy poverty metric, energy burden (10% threshold), identified 141 households as energy-insecure. Only three households overlap between our energy equity gap and the income-based measure. Thus, the energy equity gap reveals a hidden but complementary aspect of energy poverty and insecurity.
...from March 2019 to July 2019, 24 patients with renal stones underwent PCNL with the use of needle-perc needles at our hospital. 4 The pressure throughout the procedure ranged between 16 and 35 ...cmH2O (1 cmH2O = 98 Pa), which effectively avoided bacterial reflux. Because of the small size of the intra-sheath space, gravity irrigation was preferred for the needle-perc procedure. ...needle-perc is still in the early stage of clinical application, so there is much room for improvement in its handling, materials, and performance. ...needle-perc is a smart instrument for PCNL to manage some special cases.
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•Removal efficiency of iopamidol followed the order of UV/Cl2 > UV/H2O2 > .•UV/NH2Cl > UV/ClO2 > UV.•EE/O of iopamidol degradation followed the trend of ...UV/ClO2 > UV > UV/NH2Cl > UV/H2O2 > UV/Cl2.•The pH behaviors of UV-based AOPs upon iopamidol in 5–9 exhibited quite differently.•UV/Cl2 and UV/NH2Cl enhanced classical DBPs and I-THMs while UV/ClO2 and UV/H2O2 exhibited elimination effect.•The risk ranking of DBPs-related toxicity was UV/NH2Cl > UV/Cl2 > UV > UV/H2O2 > UV/ClO2.
The UV-induced advanced oxidation processes (AOPs, including UV/Cl2, UV/NH2Cl, UV/ClO2 and UV/H2O2) degradation kinetics and energy requirements of iopamidol as well as DBPs-related toxicity in sequential disinfection were compared in this study. The photodegradation of iopamidol in these processes can be well described by pseudo-first-order model and the removal efficiency ranked in descending order of UV/Cl2 > UV/H2O2 > UV/NH2Cl > UV/ClO2 > UV. The synergistic effects could be attributed to diverse radical species generated in each system. Influencing factors of oxidant dosage, UV intensity, solution pH and water matrixes (Cl−, NH4+ and nature organic matter) were evaluated in detail. Higher oxidant dosages and greater UV intensities led to bigger pseudo-first-order rate constants (Kobs) in these processes, but the pH behaviors exhibited quite differently. The presence of Cl−, NH4+ and nature organic matter posed different effects on the degradation rate. The parameter of electrical energy per order (EE/O) was adopted to evaluate the energy requirements of the tested systems and it followed the trend of UV/ClO2 > UV > UV/NH2Cl > UV/H2O2 > UV/Cl2. Pretreatment of iopamidol by UV/Cl2 and UV/NH2Cl clearly enhanced the production of classical disinfection by-products (DBPs) and iodo-trihalomethanes (I-THMs) during subsequent oxidation while UV/ClO2 and UV/H2O2 exhibited almost elimination effect. From the perspective of weighted water toxicity, the risk ranking was UV/NH2Cl > UV/Cl2 > UV > UV/H2O2 > UV/ClO2. Among the discussed UV-driven AOPs, UV/Cl2 was proved to be the most cost-effective one for iopamidol removal while UV/ClO2 displayed overwhelming advantages in regulating the water toxicity associated with DBPs, especially I-THMs. The present results could provide some insights into the application of UV-activated AOPs technologies in tradeoffs between cost-effectiveness assessment and DBPs-related toxicity control of the disinfected waters containing iopamidol.
Hierarchically porous silicon carbide (SiC) monoliths were fabricated based on polycarbosilane (PCS), divinyl benzene (DVB), and decalin, by a sequence of procedures including catalyst‐free ...hydrosilylation reaction‐induced phase separation, ambient‐pressure drying, calcination, and HF etching. The influences of ratios of each component on the phase separation were systematically studied. It was found that isotactic polypropylene added as a nonreactive additive could effectively tailor the microstructure and improve the mechanical properties of SiC monoliths. The resultant SiC monoliths mainly consisted of β‐SiC nanocrystals, and possessed low bulk density (0.7 g/cm3), high porosity (78%), large specific area (100.6 m2/g), high compressive strength (13.5 ± 1.6 MPa), and hierarchical pores (macropores around 350 nm, mesopores around 4 and 20 nm). These properties make SiC monoliths promising materials for catalyst/catalyst support, gas separator, and the reinforcement of high‐temperature composites.
Silicon carbide (SiC) monoliths with β‐SiC nanocrystals, good mechanical integrity, large SSA, and hierarchical pores were successfully fabricated via a sequence of procedures including the catalyst‐free hydrosilylation reaction‐induced phase separation, ambient‐pressure drying, calcination, and HF etching.
As applications of porous ceramic materials have gradually expanded, the novel technologies for the fabrication of porous ceramic materials with a delicate and controllable structure are still ...attractive. In this work, three types of porous monolithic ceramic materials, including Al2O3–SiO2, TiO2, and SiC, have been fabricated by thermally impacted and non‐solvent‐induced phase separations in blends of cellulose acetate and ceramic nanoparticles. These materials possessed three‐dimensional interconnected porous structures with low densities, high porosities, and hierarchical pores ranging from 5 nm to 6 μm. The relationships between microstructures and phase separations were systematically investigated. Furthermore, electromagnetic shielding effectiveness of 20 dB from 5 to 18 GHz in porous SiC materials has been achieved, revealing that those materials have potential applications in the electromagnetic shielding. This work provides a powerful and general approach to fabricate porous monolithic ceramic materials with a wide range of various ceramic nanoparticles.
Three types of porous monolithic ceramic materials, including Al2O3–SiO2, TiO2, and SiC, have been fabricated by thermally impacted and non‐solvent‐induced phase separations in blends of cellulose acetate and ceramic nanoparticles.
Nitrogen doping is a promising method for the preparation of functional carbon materials. In this study, a nitrogen-doped porous coral biochar was prepared by using bamboo as raw material, urea as ...nitrogen source, and KHCO3 as green activator through in-situ pyrolysis. The structure of the obtained biochar was characterized by various techniques including nitrogen adsorption and desorption, Raman spectroscopy, X-ray photoelectron spectrometer, and etc. The adsorption properties of nitrogen-doped biochar were evaluated with phenol and methylene blue probes. The results showed that the nitrogen source ratio had a significant effect on the evolution of pore structure of biochar. Low urea addition ratio was beneficial to the development of pore structures. The optimum specific surface area of nitrogen-doped biochar could be up to 1693 m2·g−1. Nitrogen doping can effectively improve the adsorption capacity of biochar to phenol and methylene blue. Biochar prepared at 973.15 K with low urea addition ratio exhibited the highest adsorption capacity for phenol and methylene blue, and the equilibrium adsorption capacity was 169.0 mg·g−1 and 499.3 mg·g−1, respectively. By comparing the adsorption capacity of various adsorbents in related fields, it is proved that the nitrogen-doped biochar prepared in this study has a good adsorption effect.
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In this work, the Nextel 720 continuous fiber reinforced alumina ceramic matrix composites (CMCs) were prepared by an improved prepreg process. The alumina matrix was derived from aqueous slurry, ...which consisted of organic glue, alumina sol, nanometer alumina powders, and micrometer alumina powders. This design provided a densely packed matrix for the CMC, and made the whole process relatively simple. The ratio of different alumina components in aqueous slurry was optimized to obtain good sintering activity, high thermal resistance, and excellent mechanical properties simultaneously. Furthermore, a preceramic polymer of mullite was used to strengthen the ceramic matrix through a multiple infiltration process. The final CMC sample achieved a high flexural strength of 255 MPa and a good high‐temperature stability. After 24 h of heat treatment at 1100°C, 85% of the maximum flexural strength still had been retained.
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