Search

The corrosion mechanisms that occurred between the slag-line and mold flux under the applied external electric field are studied. The results show that the slag-line can be effectively protected when the slag-line is connected to the negative electrode, and the graphite as an auxiliary electrode is connected at positive potential. Under the applied negative electric field, a thick protective adhesion layer is formed on the surface of the slag-line due to the electrochemical reactions. Additionally, the slag-line material is further reacted with surface of the formed protective layer and generates another interface reaction layer. Under the effect of double protective layers, the slag-line can be perfectly devoid of corrosion attack under the negative electric field. The performance of the slag-line and the production time of the whole continuous casting can be improved. The external electric field is expected to be a new technical approach to alleviate corrosion of the SEN.

Summary Preparation of thermally stable metal single-atom catalysts (SACs) is a challenge in heterogeneous catalysis, especially on conventional supports that provide a weak metal-support interaction. In this work, we report that a modified support MgAl2O4 can stabilize Pt single atoms by a mechanism of vapor-phase self-assembly in a high-temperature treatment (800°C, air). The experimental results on the formation mechanism and the structure are validated by DFT and ab initio molecular dynamics simulations. We infer that stable triangular K3O3 structures help stabilize Pt single atoms at high temperatures in oxidizing conditions, exhibiting excellent reactivity for methane oxidation. The obtained Pt/K/MgAl2O4 SAC presents excellent stability in methane oxidation after steam treatment at elevated temperatures, whereas the Pt/MgAl2O4 nanocatalyst suffers from rapid deactivation due to Pt nanoparticle growth. This work paves the way for preparing thermally stable and highly active SACs using conventional high-surface-area supports, despite the weak metal-support interaction.

In order to restrain the clogging in submerged entry nozzle (SEN) during the casting of rare earth steel, La–Ce alloy is explored in this work. Effects of external electric field on reaction behavior of La–Ce alloy with SEN are investigated. Results show that chemical mechanisms between La–Ce alloy and SEN during the reaction cannot be altered by electric field due to strong chemical reaction force of rare earth elements against SEN, but the speed of chemical reaction can be controlled by electric field, resulting in significant changes in reactions. By the application of positive electric field, stable and dense interface reaction layer can be formed on the surface of SEN. Specifically, newly formed protective layer can limit the formation of clogging at initial stage to continue till the end of the reaction. Proposed novel approach of external positive electric field can be expected to solve the clogging of SEN during rare earth steel casting process.

Porous mullite ceramics are potential advanced thermal insulating materials. Pore structure and purity are the main factors that affect properties of these ceramics. In this study, high performance porous mullite ceramics were prepared via aqueous gel-casting using mullite fibers and kaolin as the raw materials and ρ-Al2O3 as the gelling agent. Effects of addition of mullite fibers on the pore structure and properties were examined. The results indicated that mullite phase in situ formed by kaolin, and ρ-Al2O3 ensured the purity of mullite samples and mullite fibers bonded together to form a nest-like structure, greatly improving the properties of ceramic samples. In particular, the apparent porosity of mullite samples reached 73.6%. In the presence of 75% of mullite fibers, the thermal conductivity was only 0.289 W/m K at room temperature. Moreover, the mullite samples possessed relatively high cold compressive strength in the range of 4.9–9.6 MPa. Therefore, porous mullite ceramics prepared via aqueous gel-casting could be used for wide applications in thermal insulation materials, attributing to the excellent properties such as high cold compressive strength and low thermal conductivity.

A new strategy for preparing a novel CaO-Al2O3 auxiliary electrode coating for sulfur sensor by infiltrating Ca2+ and Al3+ into the porous ZrO2(MgO) backbone was proposed in this work. The phase composition and microstructure of the auxiliary electrode was detected and correlated to the electrochemical performance, while the application of the sulfur sensor in the liquid iron was presented. It is demonstrated that the CaO-Al2O3 particles were homogenously coated on the ZrO2(MgO) backbone and formed well connected network, which could effectively improve the reaction area between CaO-Al2O3 and [S] as well as enhancing the ionic conductivity and bonding strength of the auxiliary electrode. The assembled sulfur sensor possessed a superior sensing performance of theoretical response, simultaneously the Nernst relationship between the sensor EMF output and the linearity of the sulfur concentration occurred along with the stable, continuous, and reproducible response.

To solve the limitations of clogging and erosion of the submerged entry nozzle (SEN) for the production of high-quality special steel, the chemical reactivity between different alloys and the SEN and the interface reaction between alloys and the SEN controlled by an electric current pulse (ECP) were examined in this study. Results revealed that the chemical reactivity between different alloys and the SEN is different. For example, the reactivity between rare-earth metal and the SEN was strong, while that between Al and the SEN was extremely weak. At the same time, some differences between the clogging and interface reaction by ECP control were observed. Typically, at the positive electrode of the SEN, when a stable and dense clogging layer is formed, the internal SEN was effectively protected. However, at the negative electrode of the SEN, the decarburization rate of the SEN was accelerated by ECP, probably leading to a vicious circle of accelerated clogging and erosion of the SEN. Therefore, in the future, issues of clogging, erosion, infiltration, and decarbonization between active alloys and the SEN in the casting process may be solved and regulated by using the positive electric field of ECP. Meanwhile, the gain effect of ECP also helped to promote the homogenization of molten steel.

To meet requirements for high porosity and high strength, novel aqueous gel-casting process has been successfully developed to fabricate Al2O3-bonded porous fibrous YSZ ceramics with ρ-Al2O3 and YSZ fibers as raw materials. Microstructure, phase composition, apparent porosity, bulk density, thermal conductivity, and compressive strength of fabricated porous ceramics were investigated, and effects of fiber content on properties were discussed. According to results, bird nest 3D mesh with interlaced YSZ fibers and Al2O3 binder was formed, ensuring the ability to obtain high performance, lightweight ceramics. An increase in the number of YSZ fibers led to more complex interlaced arrangement of fibers and denser network structure of porous ceramics at retaining their stability. Furthermore, their apparent porosity and bulk density increased, whereas thermal conductivity and compressive strength decreased with increasing the fiber content. In particular, comparatively high porosity (71.1–72.7%), low thermal conductivity (0.209–0.503 W/mK), and relatively high compressive strength (3.45–4.24 MPa) were obtained for as-prepared porous ceramics, making them promising for applications in filters, thermal insulation materials, and separation membranes.

To measure the velocity of molten steel in continuous casting mould conveniently, a new method is proposed in this paper. The relationship model between thermoelectric force and velocity is establi...

Electropulsing treatment was imposed on SUS303 free-cutting steels to analyze the evolution of MnS inclusions. SUS303 steels were treated in argon atmosphere under various conditions: before the formation of MnS inclusions (1773 K), at the beginning of the formation of MnS inclusions (1678 K), and after the formation and growth of MnS inclusions (1583 K). The results show that the sizes of globular MnS inclusions decrease with an increase of current density when the electropulsing treatment is treated in the melting stage. Meanwhile, electropulsing treatment restrains the growth of inclusions due to the different conductivities between the molten steel and MnS inclusions when electropulsing treatment is treated in the solidification process. However, the number of fine rodlike MnS inclusions increases with the increase of current density in the samples treated in the inclusion nucleation stage and solidification stage because the reduction in chemical potential produced by electropulsing treatment will require less undercooling. Experimental data demonstrate that the application of electropulsing treatment is a fantastic new method to control the morphology and size of MnS inclusions in the melting stage.

This work aimed to proposing a new strategy for preparing the mullite-ZrO2 porous fibrous ceramic used as alternative matrix material for oil-water separation by the aqueous gel-casting method. The properties of the fabricated porous fibrous ceramics in terms of microstructure, phase composition, apparent porosity, bulk density and compressive strength were investigated and the separation behavior was predicted by analyzing the structural changes. It is demonstrated that the phase composition of green bodies consisted of bayerite, boehmite, ZrSiO4 and YSZ, and the sintered sample contained mullite, ZrO2 and YSZ. As the YSZ fibers increased, the porosity of the fabricated porous ceramic increased with the maximum value of 70.65% due to the formation of more pores caused by YSZ fibers. Moreover, a significant increase in compressive strength (up to 9.52–21.86 MPa) was observed with the increase of YSZ fibers. Therefore, the fabricated porous ceramics could be appropriative for advanced applications of separation membranes for oil-water separation.

In this study, the reactivity between nozzle and submerged entry nozzle and alloy elements in the steel (Al and Ce) under different electric field conditions was investigated. The results show that the decarburization of the nozzle is an important factor affecting the clogging behavior and steel quality. The external electric field directly affects and changes the decarburization, clogging, and reaction behavior between the nozzle and alloy in the steel. If the chemical reaction force between alloys and the nozzle is greater than the applied electric field force in actuality, the clogging will also occur on the submerged entry nozzle. In the future, this new method of controlling and changing the interfacial electric fields can be used to solve the problem of decarburization and clogging of the submerged entry nozzle.

The effects of morphology of ferrite and nonmetallic inclusions on corrosion resistance of as-cast 304 stainless steel (304 SS) were investigated. With the decrease in quenching temperature from 1,723 K to 1,648 K, the different microstructures of the as-cast 304 SS were obtained as the following series: austenitic-lathy δ ferrite, austenitic-colony δ ferrite, and austenitic-blocky δ ferrite and the average inclusion size increased. The electrochemical results show that the sample with the microstructure of austenitic-lathy δ ferrite and smaller size inclusions had a higher corrosion tendency and the lower pitting resistance. Furthermore, the effect of morphology and content of ferrite on corrosion resistance was greater than that of inclusion size under the current experimental conditions. Therefore, a promising method was developed to improve the corrosion resistance of as-cast 304 SS by changing the solidification process.

In this study, porous mullite ceramics were prepared by gel-casting using fused mullite particles as the raw materials, ρ-Al2O3 and polysilicon waste as the binders, and starch as the pore forming agent. In addition, the effects of pore forming agent content on the apparent porosity, compressive strength, pore size distribution, thermal analysis, and pressure drop of porous mullite ceramics were studied. The results show that the as-prepared porous mullite ceramics have high apparent porosity, compressive strength, and gas permeability. Mullite phase formed in situ by adding polysilicon waste and ρ-Al2O3, which bonded the fused mullite particles and improved the performance of porous mullite ceramics. With increasing soluble starch content, the apparent porosity of the samples increased from 49.50 to 62.67%, and the compressive strength decreased from 4.98 MPa to 1.35 MPa. Furthermore, uniform pore size distribution and high gas permeability fully meet the requirements for the application of high-temperature flue gas filtration.

Simply constructing multiple responsive polymers with obvious shape and dimension variations on their assemblies upon different stimuli is still rarely reported. In this study, we report a hyperbranched polymer named HPAzoBAHB-star-PEG9 with quadruple-response to light, temperature, pH and oxidation stimuli. The polymer contains azobenzene chromophore, sulfide, amide and amine groups in its hydrophobic hyperbranched core, and the core is capped with hydrophilic polyethylene glycol (PEG9) arms. HPAzoBAHB-star-PEG9 could assemble into unusual leaf-like lamellar micelles at 25 °C under the guidance of orderly arranged H-aggregate of azobenzene moieties. These leaf-like lamellar micelles can transform into vesicles upon UV irradiation and lower temperature, or convert to smaller spherical micelles in acidic or oxidative environments, respectively, with the destroy of ordered azobenzene arrangements. This quadruple-responsive hyperbranched polymer is suitable to construct multiple stimuli-responsive micro/nanostructures, or accurate delivery and release following subtle stimuli sequences.

In order to use polysilicon cutting waste more efficiently, SiC/α-Si3N4 composite powders were prepared via electromagnetic induction heating at ambient pressure. Factors affecting synthesis and reaction mechanisms of the SiC/α-Si3N4 composite powders were investigated. Results show that the morphology of obtained α-Si3N4 consists of particles equiaxed with diameter in the micron range and one-dimensional Si3N4 nanowires with diameter of tens to hundreds of nanometers and length of up to tens of microns. It was found that the addition of NH4Cl can promote nitridation by controlling reaction temperature and participating in the reaction. In addition, the existence of Fe2O3 impurities was found to be beneficial to the formation of α-Si3N4 in reaction process by removing the SiO2 film from silicon and providing FeSi2 liquid phase as effective pass for vapor phase. Mechanisms used to grow Si3N4-NWs were vapor-solid (VS) and vapor-liquid-solid (VLS) depositions.

In this paper, a novel pectin gel-casting method was developed to prepare porous MgAl2O4 ceramics using MgO and Al2O3 powders as raw materials and ficus pumila seeds as the gel source. The effects of pectin content on the properties of MgAl2O4 porous ceramics, such as phase composition, microstructural characteristics, apparent porosity, bulk density, compressive strength, and thermal conductivity, were investigated. The results showed that the linear shrinkage of the samples was about 5%, indicating a near-net shape method. With the increase of pectin content, the porosity of porous MgAl2O4 ceramics increased significantly. The prepared MgAl2O4 porous ceramics with different pectin contents showed high apparent porosity of 58.7–70.1%, low thermal conductivity of 0.328–0.840 W/(mK), and relatively high compressive strength of 0.27–2.45 MPa. The proposed method as a near-net shape forming method provided a novel feasible gel-casting method to fabricate other porous ceramics.

The present work focused on developing a novel hydrophobic and lipophilic material for oil-water separation based on mullite fiber-based porous ceramics as the matrix material and octadecylamine (ODA) with low surface energy as the coating material. The bionic surface grafting technology was used to modify the porous ceramics, forming a multi-level structure used as the superhydrophobic membrane. The oil adsorption capacity, oil holding capacity and recyclability of the material for various oils were investigated. It was demonstrated that the modified ODA coating made the mullite fiber-based porous ceramics hydrophobic and lipophilic and could achieve fine effect of oil-water separation in a short time. The oil absorption performance was affected by the types of oil and the maximum adsorption capacity was generally more than 1 time of its own mass. Meanwhile, excellent oil holding capacity and recyclability were observed.

High-purity calcium hexaluminate (CA6) porous ceramics have been prepared with novel pectin based gelcasting freeze-drying method. CaCO3 and Al2O3 were used as raw materials and ficus pumila pectin was used as gelling agent. Effects of solid content on properties of CA6 porous ceramics, such as phase composition, microstructural characteristics, apparent porosity, bulk density, compressive strength, and thermal conductivity have been investigated. Pores in CA6 ceramics are found to be mainly formed by water molecules sublimation during freeze-drying and organic decomposition processes. Moreover, freeze-drying method is shown to be beneficial to improve heat insulation performance of porous ceramics. As-prepared CA6 porous ceramics with different solid contents possess high apparent porosity of 66.4-75.1%, low bulk density of 0.90-1.20 g/cm3, low thermal conductivity of 0.227-0.360 W/(mK), and relatively high compressive strength of 0.71-2.06 MPa, which fully meet requirements for their functional and structural applications.

The effect of an electric field with different polarities on the inner wall of a submerged entry nozzle made of rare earth steel was investigated. The results show that the electric field induces a change in the decarburization, erosion, and clogging processes of the nozzle. In the casting of rare earth steel, the negative electric field affects the decarburization, erosion, and clogging of the nozzle. Moreover, when a reverse positive electric field is applied on the wall of the submerged entry nozzle, these processes can be effectively reduced. This ensures the integrity of the submerged entry nozzle and its smooth production during the continuous casting process.

The photoreduction of diluted CO2 into value-added solar fuel is a discipline at the forefront of energy and environmental research. However, this exploration largely suffers from unsatisfactory activity and selectivity. Herein, lattice-strained nickel hydroxide nanosheets (NSs) were successfully constructed via a vanadium-doped strategy toward the photoreduction of diluted CO2. X-ray absorption fine structure spectroscopy and Williamson–Hall analysis based on X-ray diffraction revealed the formation of lattice strain on the surface of the Ni(OH)2 NSs. Consequently, the lattice-strained sample exhibited the highest CO production yield of 20.7 μmol with a CO selectivity of 97% after 3 h in pure CO2, which were almost 4 and 1.3 times those of its parent Ni(OH)2 NS. Even in diluted CO2 (0.1 atm), it exhibited a CO production rate of 5.8 μmol h−1 with a CO selectivity of 91.3%, surpassing most previous works in pure CO2. Further characterizations revealed that the lattice strain could greatly improve the CO2 adsorption and activation, and the separation efficiency of the photogenerated carriers, thus leading to an enhancement in the carbon dioxide reduction activity. This work discloses a clear atomic-level correlation between lattice strain and diluted CO2 photoreduction, which lays a foundation for reinventing their applications in photocatalysis, among other applications.

Nanocrystalline tin (IV) oxide (SnO2) electron-transport layers (ETL) have shown great potential for achieving highly efficient, stable perovskite solar cells (PSCs), in particular low-temperature-processed flexible PSCs. Recently, studies have further shown that a modified SnO2 bottom layer facilitates the deposition of highly crystalline perovskite films, boosting the photovoltaic performance of the PSCs. The modulation of perovskite crystallization processes is a key to obtain highly crystalline and stable perovskite films; however, a fundamental understanding is still missing. Herein, we report an in situ synchrotron-based two-dimensional grazing-incidence X-ray diffraction technique to explore the SnO2 ETL-modulated perovskite crystallization kinetics for the first time. The titanium carbide (Ti3C2Tx)-MXene quantum dot-modified SnO2 (MQDs-SnO2) ETL was found to be able to rapidly induce perovskite nucleation from the precursor solution, forming an intermediate perovskite phase upon anti-solvent treatment. This substantially improves the crystal quality and phase stability of the as-fabricated perovskite film. Benefiting in addition from the superior charge extraction properties of the MQDs-SnO2 layer, a steady-state power conversion efficiency of up to 23.3%, as well as outstanding stability against humidity and light soaking was achieved for the corresponding PSCs.

MgO-ZrO2 ceramics were prepared using MgO powder calcined with crystal magnesite as starting material and TiO2 as an additive. Samples were mixed with different mass fractions of ZrO2 powder and sintered at 1600 °C for 2 h. Effects of added amounts of ZrO2 and TiO2 on the performance of MgO–ZrO2 ceramics were investigated. Results showed that increase in mass fraction of added ZrO2 or addition of small amount of TiO2 significantly promoted performance of MgO–ZrO2 ceramics. Moreover, the improvement effect of TiO2 was more obvious than that of ZrO2. Addition of TiO2 promoted solid solution reaction of ZrO2 and MgO, which was the main reason for improved densification. In addition, TiO2 and CaO form CaTiO3, whereas free SiO2 and MgO form Mg2SiO4. These two compounds filled the pores between MgO and ZrO2 grains and improved densification, compressive strength, and thermal shock resistance.

Sintered MgO was prepared by using MgO powder with different particle sizes by calcination of by crystal magnesite as the raw material and CeO2 powder as an additive. In addition, the effect of the CeO2 addition on the performance of the sintered MgO was investigated. The results showed that (i) the densification of the sintered MgO with a small amount of CeO2 addition appreciably promoted, (ii) the maximum bulk density reached 3.48 g cm−3, and (iii) the apparent porosity was 0.35%. In the sintering process, the Ca2+ could approach into CeO2 lattices, forming O2− vacancy at CeO2 grains, which resulted in promoting the growth of CeO2 grains filling the pores between the MgO grains, and enhanced the densification of sintered MgO. In addition, the solid solution reaction limited the formation of silicate phase in MgO, improving the bonding degree between the MgO grains.

Recycling methods will be essential for the future circular economy in the context of declining natural resources. Nanomaterials are promising adsorbents to recover rare earth elements from wastewater, yet the practical application of nanomaterials is limited by spontaneous agglomeration, easy collapse of structures and the difficulty in collecting nanomaterials after adsorption. To solve these issues, we prepared a polyurethane sponge-supported titanium phosphate with graphene oxide, abbreviated as GO@TiP-Sponge, by in situ precipitation. GO@TiP-Sponge was characterized by X-ray diffraction, scanning electron microscope, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, and tested for the removal and recovery of trace dysprosium Dy(III), a rare-earth element, in water using batch experiments. Results show that the GO@TiP-Sponge showed an excellent affinity for dysprosium with theoretical capacity reaching 576.17 mg/g according to the Langmuir model. Half-equilibrium was reached in 2.5 min according to a pseudo-second-order model. GO@TiP-Sponge also displayed an adsorption ability for a wide range of pH and salinity. Such performance is explained by strong binding of phosphate with Dy(III), enhanced surface area induced by graphene oxide and less aggregation from the spongy structure. The main adsorption mechanism involves electrostatic interaction.

Clogging behavior has been investigated by applying a direct current on a submerged entry nozzle (SEN). The relevant experimental results verify that the high-speed friction acting on the SEN not only leads to charging of the inclusions, but also inhibits the clogging behavior and improves the quality of the steel. After DC treatment, the formation of clogging in the SEN decelerates and the stability improves, such that the density of clogging increases and the porosity of clogging decreases significantly. Meanwhile, after applying a DC electric field, the overall quality of steel is also improved.

Electropulsing has been imposed on molten AISI 304 stainless steel and its effects on the inclusion size and corrosion properties have been investigated. The average size of inclusions in electropu...

A novel phosphorus sensor based on the bilayer structure of ZrO2(MgO)/CaAl1.64O3.46 was fabricated and tested in high phosphorus liquid iron in this work, where the 4CaO∙P2O5 used as the auxiliary electrode was synthesized in situ by the CaAl1.64O3.46 layer during the measurement. The results indicated that phosphorus sensor showed fairly good reproducibility and sensibility to phosphorus content in high phosphorus liquid iron and the empirical equation was obtained. The application conditions of this phosphorus sensor were that the relationship between a [ P ] and a [ O ] should be satisfied to be ln a [ P ] 2 a [ O ] 5 ≥ − 29 .30 at 1773 K and ln a [ P ] 2 a [ O ] 5 ≥ − 26 .40 at 1823 K. After the measurement, the 4CaO∙P2O5 was detected in the CaAl1.64O3.46 layer and further confirmed that the auxiliary electrode had been formed in situ in the liquid iron. This work would be beneficial to online detecting the phosphorus content in the dephosphorization process of high phosphorus liquid iron and then improve production efficiency.

The combined effects of W, Mn and Mo additions on the microstructure and properties of a hypereutectic high chromium cast iron (HCCI) were studied. The results indicated that W was distributed uniformly in the matrix and carbides. The W and Mo addition promoted the formation of M2C and M6C carbides. When 13 wt.% Mn was added to the samples, the solubility of Mn in the matrix increased the stability of the austenite phase and improved the toughness of the materials. Moreover, Mn and Cr form the M7C3 carbides in hypereutectic HCCI. A large number of (Fe, Mn)3C carbides were produced in the matrix during the later stage of solidification, which significantly improved the wear resistance of the matrix. When the amount of W, Mn and Mo added was 6 wt.%, 15 wt.% and 4.2 wt.%, respectively, the HCCI exhibited the best performance herein. The addition of 6 wt.% W led to an increase in the average hardness of the samples and the microhardness of carbides of up to 57.5 HRC and 1680 HV, respectively. Similarly, it is worth mentioning that the impact toughness of the 6% W sample reached 6.35 J/cm2, and the mass loss of the Cr16 and 0% W samples was 1.43 and 1.23 times that of the 6% W sample, respectively. The wear resistance of the 6% W sample showed no significant change before and after heat treatment. The combination of W, Mn and Mo simultaneously improved the wear resistance and impact toughness of the hypereutectic HCCI.

To achieve simple and efficient synthesis of CeAlO3, novel high-temperature carbon-bed method was developed to synthesize CeAlO3. Results demonstrate that reaction temperature is more important factor than reaction time in synthesis process and affects reaction rate and products. With increasing reaction temperature and time, CeAlO3 crystals grow. However, the purity of CeAlO3 is affected if reaction temperature is too high or reaction time is too long. The best CeAlO3 product in this study was obtained when reaction temperature was 1400 °C and reaction time was 4 h.

The behavior and mechanism of in-situ synthesis of the auxiliary electrode for sulfur sensor were investigated in this work, aiming for better application of calcium aluminate system in synthesizing the auxiliary electrode used for sulfur sensor. The in-situ reaction experiment was developed. In addition, the thermodynamic and kinetic calculations were adopted to further study the in-situ reaction possibility and the reaction rate. The results indicated that the value of lg(a[S]/a[O]) should be greater than a particular value to ensure the occurrence of the in-situ reaction. After immersion into the molten iron, the CaS phase was synthesized in the calcium aluminate system. The relationship between the reaction rate and reaction time was exponential, and the initial reaction rate was affected by the CaO content incorporated in the calcium aluminate system and the sulfur content in the molten iron. The initial in-situ reaction rate greatly increased with the increase of the CaO content and sulfur content. For example, the initial reaction rate was as high as 14.87 s-1 when the calcium aluminate system containing 60 wt% of CaO and for a sulfur content of 0.077 wt% in the molten iron. Moreover, the reason that the sulfur sensor fabricated by the ZrO2(MgO) tube with the calcium aluminate coating with different components had the same response time when measuring the different sulfur contents in the molten iron was further explained.

In the present work, gas sensors based on Cr2WO6 nanoparticles were fabricated by a screen-printing technique, and the sensing properties were characterized with acetone and other typical reducing gases under both dry and humid air backgrounds. Interestingly, it was found that Cr2WO6 sensors showed a p-type conduction characteristic with a highly sensitive response to acetone vapor in a relatively low concentration. In the presence of humidity, resistances of Cr2WO6 sensors were significantly increased; nevertheless, sensor responses were obviously inhibited. In addition, the basic sensing mechanism of Cr2WO6 sensor was also investigated based on oxygen adsorption behavior and catalytic properties of Cr2WO6 surface. According to experimental results, it is proposed that the resistive responses of Cr2WO6 sensor to reducing gases were highly oxygen-dependent, indicating that the surface oxygen adsorption and reaction also played the basic role in the sensing process as that observed in typical n-type MOS sensors. Additionally, sensors also suffered from a high cross-sensitivity to water vapor due to the competition of chemisorption of water and oxygen on the surface of Cr2WO6.

The assembly of paddle-wheel Ru2 building units affords a new trimetallic carbonate, Cs3Cd(H2O)6[{Cd(H2O)3}2{Ru2(CO3)4}3]·10H2O (1), that contains structurally near-perfect kagome layers, {Ru2(CO3)4}n3n-, linked by octahedral Cd(H2O)32+ into a nanoscale kagome network exhibiting ferromagnetic ordering below 3.5 K. The investigation of influences of the grinding method on the crystal samples of compound 1 reveals that the coercivity increases from ∼2.5 Oe to 44.0 Oe upon a grinding treatment for 180 minutes. The results demonstrate that compound 1 can vary from a soft magnet to a hard magnet simply by manually grinding the crystal samples to the nanoscale.

Control of magnetic performances of molecular magnets is essential but few efforts have been documented. A green and efficient sonication assisted synthesis of a new heterometallic diruthenium(II,III) carbonate, Na[Ni(H2O)4Ru2(CO3)4]·3H2O (1), was carried out by self-assembling in aqueous solution. Compound 1 exhibits spin-glass behavior below ∼5.0 K, and a systematic investigation of the ultrasonic irradiation influence on the powder samples reveals that their coercivity increases from 50 Oe to 743 Oe with the control of ultrasonic power under appropriate conditions.

WC particle/HCCI composites were prepared using liquid-phase sintering technology. In this study, millimeter WC particles were used to ensure that minimal WC particle performance was compromised during the preparation process. Moreover, with the aim of controlling the evolution of microstructures and secondary carbide precipitation in the matrix, different heat treatment methods were adopted in the manufacturing process. The microstructures of the composites were investigated via SEM, XRD, EPMA and TEM. The results showed that perfect metallurgical bonding was formed between the LCS and the WC/HCCI composites, and the width of the diffusion layer was 120 to 129 µm after heat treatment. A large number of secondary carbides precipitated in the matrix during heat treatment, and martensite formation occurred in the matrix during the subsequent cooling process, which effectively increased the microhardness of the matrix. The impact toughness of the LCS-toughened composites after heat treatment was 1.6 times that of the WC/HCCI composites, and the shear strength was 5 times that of the as-cast composites. The wear resistance of the composites under quenching at 950 °C and tempering at 220 °C was 5 times that of the as-cast composites.

The ZrO2(MgO)/CaO-Al2O3 bilayer system used as the solid electrolyte for sulfur sensor was fabricated by screen-printing technology using ZrO2(MgO) electrolyte as the substrate and CaO-Al2O3 compounds with different compositions as the coating materials. The effect of the CaO content in the CaO-Al2O3 compounds on the properties of the bilayer systems were investigated in terms of the phase composition, structure and ionic conductivity. It was demonstrated that all the bilayer systems were dense and uniform and a considerable increase in ionic conductivity was observed with increasing temperature and CaO content in CaO-Al2O3 compounds. The increase in total ionic conductivity at the same temperature was mainly attributed to the increase in the grain boundary conductivity. The grain boundary conductivity of the bilayer systems increased exponentially with increasing the CaO content while the total ionic conductivity increased linearly, which could satisfy the requirement of the ion conduction in solid electrolyte for sulfur sensor.

Design of low–cost and efficient materials with appropriate composition and configuration is desirable for supercapacitor electrode. In this work, hierarchical silica@manganese silicate core–shell spheres with controllable particle size and shell thickness are fabricated through a facile hydrothermal method. The monodispersed core–shell spheres dispaly the hierarchical structure composed of manganese silicate crystallites. The dependence of electrochemical performance on the particle size and the shell thickness is investigated. The finding demonstrates that the core–shell sphere prepared using small silica sphere possesses superior electrochemical properties. A specific capacitance of 297.3 F/g at a current density of 0.5 A/g is achieved. And the thick shell is also in favour of enhancing specific capacitance. The excellent surface–dependent electrochemical performance is associated with its distinctive hierarchical structure, which effectively shortens the ion/electron migration pathway and provides enough electroactive sites. The hierarchical core–shell spheres can be potentially applied in low–cost electrode for supercapacitor.

The problem of the clogging of submerged entry nozzle (SEN) in the continuous casting of bearing steel containing rare earth (RE) elements is studied in this paper. The composition, formation process, growth mode and cause of the clogging at the interface of the molten steel and the refractory of SEN were analysed in detail during the process of molten steel casting. The results showed that the graphite dissolution process on the inner wall of SEN can improve the wettability between the molten steel and the refractories, which provides convenient conditions for the reaction and adhesion of RE and its compounds on the inner wall of the SEN. Clogging compounds at different locations had different compositions. The main compositions at the interface between the molten steel and the refractories were consisting of cerium aluminate compounds, while the outer walls of the SEN mostly consisted of cerium sulfide compounds. With the growth of clogging, the laminar flow interface layer on the inner wall of the SEN will gradually increase, which further accelerates the clogging, and ultimately affects the continuous casting. Therefore, the prevention of clogging in the SEN of RE steel can be mainly carried out by inhibiting the formation of initial clogging in the early stages and by inhibiting the reaction of the SEN materials.

In the past few decades, nanomaterials have attracted great attention as promising adsorbents for the recovery of rare earth elements (REEs) from wastewater. However, there are still some shortcomings in the application of nanomaterials to the adsorption of REEs, such as poor mechanical properties, easy collapse of structure, and difficulty in collection in practical application. In this study, sodium alginate supported nano-Mg(OH)2 (SA@Mg(OH)2) composite beads were prepared by adding Ca2+ as a cross-linking agent in a mixed suspension of sodium alginate and synthesized flower-like nano-Mg(OH)2, and were applied to remove and recover the low-concentration REEs from water. The analysis of the phase component and micromorphology of the composite beads revealed that the nano-Mg(OH)2 maintained a flower-like structure and distributed homogeneously throughout the sodium alginate beads. The adsorption experiments showed that the SA@Mg(OH)2 can fully adsorb Eu(III) with an adsorption capacity up to 394.61 mg/g, and keep a good mechanism performance after adsorption without collapse of the structure. Therefore, the excellent performance of SA@Mg(OH)2 indicates that loading environmentally functional materials on sodium alginate is a promising method to accelerate the environmental application of nanomaterials in wastewater treatment.

Reducing carbon dioxide (CO2) to various value-added chemical products by photocatalysis could effectively alleviate the serious problems of global warming and energy shortages. Currently, most commonly prepared photocatalysts present poor performance under visible light irradiation. In this study, we adopted a facile, scalable and controllable approach to prepare ultrathin two-dimensional (2D) porous Co3O4 catalysts (Co3O4-NS) by air calcining of the ultrathin metal-organic framework (MOFs) nanosheet templates to validly reduce CO2 with a Ru-based photosensitizer under visible light irradiation. Benefitting from the structural nature of MOFs precursors, the calcined Co3O4-NS inherit the morphology of 2D and well-developed porosity, which support the transport of electrons, enhance the adsorption of CO2 molecules, and render abundant catalytic sites for CO2 activation. As a result, the CO generation rate is approximately 4.52 μmol·h−1 with selectivity of 70.1%, which is superior to the Co3O4 bulk catalysts (Co3O4-BK). Additionally, density functional theory (DFT) calculations reveal that the model of Co3O4 monolayer has stronger CO2 adsorption energy than that of the Co3O4 bulk, which is beneficial for the CO2-to-CO conversion. This MOF-engaged strategy provides new insight into the controlled synthesis of advanced ultrathin holey nanosheets to improve the efficiency of photocatalytic CO2 reduction.

In this work, zinc ferrite spinel with different zinc contents (ZnxFe3-xO4) was synthesized by a hydrothermal method and used for removing As(V) in aqueous solution. X-ray diffraction (XRD) results indicated that in the crystal structure of ZnxFe3-xO4, the zinc atoms tended to occupy the octahedral sites for x 0.6. The size of ZnxFe3-xO4 crystallites increased with the increasing zinc content. Batch adsorption experiments showed that the adsorption isotherms could be well described by the Langmuir model, while the adsorption kinetics followed the pseudo-second-order kinetic model. Zinc ferrite exhibited the highest adsorption capacity towards As(V) when x = 0.6. Study of the mechanism indicated that doping with zinc increased the number of surface hydroxyl groups on ferrite spinel, and thus enhanced the adsorption capacity when x = 0.6. This work revealed the effects of doping site and content of metal atoms on the adsorption ability of ferrite spinel towards As(V).

A composite grating structure composed of two-dimension SiC grating and multilayer films substrate is proposed. Surface phonon polariton is excited by the SiC grating to yield a absorption peaks at 10.6 μm. Ag and ZnS are selected to design multilayer films which have high absorption at 1.06 μm and high transmission for visible light. Meanwhile, the films has high spectral reflectance in the near, middle and far infrared band. By optimizing, the composite grating can satisfy the laser and infrared compatible stealth while achieving high visible transmittance.

In present study, two group of WO3-x nanocrystals (NCs) have been prepared via a facile solvothermal process and their photocatalytic activities for dehydration of isopropyl alcohol (IPA) to propylene (C3H6) under visible light irradiation have been studied. The photocatalysts are characterized by XRD, FSEM, HRTEM, XPS and UV–vis spectroscopic study. As for WO3-x NCs synthesized under different temperature, the highest photocatalytic efficiency was achieved for the W18O49 NCs prepared at 160 °C at C3H6 evolution rate of 145 μmol h−1 g−1. When it comes to the WO3-x NCs obtained using different solvents, the sea urchin-like W18O49 microspheres synthesized in ethanol has the greatest activity for photocatalytic dehydration of IPA. Their outstanding photocatalytic performances may stem from the large amount of oxygen vacancies (OVs) on their surfaces. The above results suggest the high potential of WO3-x NCs in application for C3H6 production.

Background The most common materials of artificial blood vessels are polyethylene terephthalate and polytetrafluoroethylene. But polycarbonate polyurethane (PCU) is an ideal material for vascular prostheses because of their excellent characteristics. As far as we know, our artificial blood vessel is the first type of hybrid PCU/polyester three-layered large-diameter artificial blood vessel in the world. Objective The purpose of this preclinical animal experiment is to evaluate the hemocompatibility, histocompatibility, effectiveness, and safety of the three-layered large-diameter artificial blood vessel in sheep. Methods The artificial blood vessels took place of the initial segments of the sheep’s thoracic aorta by end-to-end anastomosis. Results All of the 14 sheep are male, their average body weight (BW) was 30.57 ± 3.95 kg. All 14 artificial blood vessels successfully replaced the thoracic aortas. 5 sheep did not survive to the end of the experiment, while the remaining 9 sheep did. After the surgery, the blood biochemical and blood routine indicators fluctuate slightly within the normal range. The angiography showed that the implanted artificial blood vessels were unobstructed without obvious stenosis or expansion. 24 weeks after surgery, the lumen surfaces of the artificial blood vessels were covered by endothelia in different degrees, and the average endothelialization rate was 69.44% (range: 20% to 100%). Conclusions This artificial blood vessel is the first to use PCU in large-diameter artificial vascular grafts. It has excellent blood compatibility, wonderful biocompatibility, high endothelialization rate, and 100% patency.

A vacuum-induced multistage atomization process was adopted to fabricate the high-performance 304 stainless steel powder for 3D printing, based on the flexible control of the droplet spheroidization and solidification process. The 36.7 μm-median diameter (D50) 304 stainless steel powder with high sphericity was successfully obtained, together with particle size proportion of 45–55 μm larger than 35% and the lower oxygen and nitrogen content increment below 0.04%.

Preparation of thermally-stable metal single atom catalysts (SACs) is a challenge in heterogeneous catalysis, especially on conventional supports that provide a weak metal-support interaction. In this work, we report that conventional support MgAl2O4 can stabilize Pt single atoms by a mechanism of vapor-phase self-assembly when using a potassium-containing salt at a high temperature treatment (800 oC, air). The obtained Pt/K/MgAl2O4 SAC has a high surface area of ca. 100 m2/g, which is ten times higher than that when supported on ceria with strong metal-support interaction involving the same method. We found that the Pt single atoms via this vapor-phase self-assembly preferentially locate at the MgAl2O4 (111) plane for the Pt/K/MgAl2O4 SAC. The experimental results on the formation mechanism and the structure are discussed and validated by density functional theory calculations and ab initio molecular dynamics simulations. We infer that stable triangular K3O3 structures help to stabilize Pt single atoms at high temperatures in oxidizing conditions, showing the higher reactivity than a Pt/CeO2 single atom catalyst in methane oxidation. The obtained Pt/K/MgAl2O4 SAC presents excellent stability in methane oxidation after steam treatment at elevated temperature, whereas a Pt/MgAl2O4 suffers from rapid deactivation due to Pt nanoparticle growth. This work paves the way for preparing thermally-stable and highly active SACs using conventional high-surface-area supports, despite providing only a weak metal-support interaction.

The low frequency power loss of two 1200V planar gate field-stop insulated gate bipolar transistor (IGBT) devices with different power rating is measured with double pulse test method. The switching loss and saturation loss with various collector current values are analyzed. The results show that power loss is strongly correlated with the device area and collector current. Device temperature is 6.6K lower for large area device when operating with collector current at 10A. The saturation power loss and turn-off trailing loss are discussed as well. Finally, the methods for power loss reduction are discussed from the standpoint of device structural design, layout optimization and manufacturing process.

The efficacy of photodynamic therapy (PDT) in the solid tumor is hampered by many challenges, including its oxygen self-consuming nature, insufficient oxygen levels within the hypoxic tumor microenvironment, and limited penetration of photosensitizers within tumors. Herein, we develop the IR780@O2-SFNs/iRGD as an oxygen self-sufficient and tumor-penetrating nanoplatform, which consists of IR780-loaded pH-sensitive fluorocarbon-functionalized nanoparticles (SFNs) and iRGD as a tumor targeting peptide that can penetrate deeper within the tumor. Because of the high oxygen affinity and outstanding permeability of the obtained nanoplatform, oxygen and IR780 which are encapsulated in the same core can play their roles to the utmost, resulting in remarkably accelerated singlet oxygen production, as demonstrated in vitro by the 3D multicellular spheroids and in vivo by tumor tissues. More interestingly, a single-dose intravenous administration of IR780@O2-SFNs/iRGD into mice bearing orthotopic breast cancer could selectively accumulate at the tumor site, highly alleviate the tumor hypoxia, significantly inhibit the primary tumor growth, and reduce the lung and liver metastasis, enabling the improved photodynamic therapeutic performance. Thus, this work paves an effective way to improve PDT efficacy through increasing tumor oxygenation and selective delivery of photosensitizers to the deep and hypoxic tumor.

Considering p-arsanilic acid (p-ASA) as an organoarsenic pollutant, monitoring concentration of p-ASA is significant to maintain environmental security. Photoelectrochemical (PEC) detection is promisingly applied in environmental monitoring for its lower cost and simpler operation, compared to traditional techniques. However, general electrode materials of PEC sensors need to be modified with biological probes due to lack of specific binding sites to analytes, which may lead to complicated sensor fabrication and bio-recognizers inactivation during storage. Herein, a porphyrinic metal–organic framework/reduced graphene oxide (PCN-224/rGO) nanocomposite with simultaneously excellent photoelectric activity and strong binding characteristics was prepared and used to fabricate a PEC sensor for p-ASA detection avoiding the modification of bio-recognizers. Benefiting from the high conductivity of rGO, the separation efficiency of charge carriers was improved in PCN-224/rGO and thereby photocurrent gained an amplification of about 12 times. The PCN-224/rGO nanocomposite had strong affinity to p-ASA via Zr–O–As coordination and π–π stacking. Significantly, the binding of p-ASA could adjust the band position of PCN-224/rGO and facilitate oxygen reduction by releasing more photogenerated electrons, achieving photocurrent enhancement. The developed PEC sensor had a wide detection range, from 10 ng L−1 to 10 mg L−1, with a detection limit of 5.47 ng L−1. Furthermore, the sensor was successfully applied to monitor p-ASA in simulated natural water and swine manure lixivium. This study paved the way for the design of more efficient PEC sensors for environmental monitoring.