Search

Rechargeable batteries are promising platforms for sustainable development of energy conversion and storage technologies. Highly efficient multifunctional electrodes based on bimetallic sulfides for rechargeable batteries are extremely desirable but still challenging to tailor with controllable phase and structure. Here, we report a colloidal strategy to fabricate FeCo-based bimetallic sulfides on reduced graphene oxide (rGO), which are expected to display highly efficient oxygen electrocatalysis and sodium storage performances. Specifically, as-screened FeCo8S8 nanosheets (NSs) on rGO originating from suitable tailoring of the Co9S8 matrix with Fe at the atomic level exhibited a very low potential difference (0.77 V) at 10 mA cm-2 and negligible voltage loss after 200 cycles as an air electrode for Zn-air batteries. For Na-ion batteries, FeCo8S8 NS/rGO demonstrated a superior high-rate capability (188 mAh g-1 at 20 A g-1) with long-term cycling stability. The bifunctional electrocatalytic property and sodium storage performance are attributed to not only the synergistic effect of Fe/Co but also the optimized catalytic activity and ion transport ability by the in situ rGO hybrid. This work demonstrates the potential applications of FeCo-based bimetallic sulfides as efficient electrode materials for both rechargeable Zn-air and Na-ion batteries.

Among all segmentation techniques, Otsu thresholding method is widely used. Line intercept histogram based Otsu thresholding method (LIH Otsu method) can be more resistant to Gaussian noise, highly efficient in computing time, and can be easily extended to multilevel thresholding. But when images contain salt-and-pepper noise, LIH Otsu method performs poorly. An improved LIH Otsu method (ILIH Otsu method) is presented, which can be more resistant to Gaussian noise and salt-and-pepper noise. Moreover, it can be easily extended to multilevel thresholding. In order to improve the efficiency, the optimization algorithm based on the kinetic-molecular theory (KMTOA) is used to determine the optimal thresholds. The experimental results show that ILIH Otsu method has stronger anti-noise ability than two-dimensional Otsu thresholding method (2-D Otsu method), LIH Otsu method, K-means clustering algorithm and fuzzy clustering algorithm.

The anoxic decomposition and influence of carbon precursors on the properties of LiFePO4/C prepared by using Fe2O3 were investigated. X-ray powder diffractometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and carbon content and charge–discharge tests were applied to the characterization of the as-synthesized cathodes. Partial carbon is lost in the anaerobic decomposition of organic precursors and a high hydrogen content leads to a high residual carbon rate. Pyromellitic anhydride and citric acid participate in reactions before and in ball-milling. All the chosen carbon precursors are capable of producing LiFePO4 with high degree of crystallinity and purity. The carbon derived from α-D-glucose, pyromellitic anhydride, soluble starch, citric acid and polyacrylamide has a loose and porous texture in LiFePO4/C which forms conduction on and between LiFePO4 particles. LiFePO4/C prepared by using α-D-glucose, pyromellitic anhydride, citric acid and sucrose exhibits appreciable electrochemical performance. Graphite alone is able to enhance the electrochemical performance of LiFePO4 to a limited extent but incapable of preparing practical cathode.

LiFePO4/C was prepared via solid state reaction and characterized with X-ray powder diffraction and charge–discharge test. As-prepared LiFePO4/C has a triphylite structure and exhibits an excellent rate capability and capacity retention. Electrochemical impedance spectroscopy (EIS) was applied to investigate Li x FePO4/C (0

Based on the simulation of the air conditioning construction dynamic load and simulation calculation of air-source gas engine-driven heat pump (GEHP), the air-source GEHP air conditioning in winter, summer and the annual primary energy ratio are analyzed in simulation with the combination of a hotel building in Tianjin. Firstly, DeST software is used to simulate all-year hourly air conditioning load of the building. Then air-source GEHP simulation model [1] is used to calculate the annual hourly gas consumption and the amount of GEHP's gas consumption in winter, summer and a total year afterwards can be got. At the same time, by the analysis of waste heat recovery of gas engine-driven, primary energy ratio for air-source GEHP in Tianjin is given under the different waste heat recovery of winter, summer and the annual.

This article uses Finite-difference time-domain (FDTD) method in the spray quenching process of the backup roll, which calculated the temperature field, the phase transformation and the hardness of the backup roll. The results showed that there was high temperature gradient on the surface of back up roll at the beginning of the spray quenching process and the tempeurature decreased rapidly. The beginning of the spray quenching process is a key stage. The radius martensite content decreases from outside to inside gradually, the maximum depth that martensite occurs was about 150mm from the surface. Martensite point affected the surface hardness very slightly, whereas impacted the hardening depth strongly.

Traditionally, the optimization algorithm based on physics principles has some shortcomings such as low population diversity and susceptibility to local extrema. A new optimization algorithm based on kinetic-molecular theory (KMTOA) is proposed. In the KMTOA three operators are designed: attraction, repulsion and wave. The attraction operator simulates the molecular attraction, with the molecules moving towards the optimal ones, which makes possible the optimization. The repulsion operator simulates the molecular repulsion, with the molecules diverging from the optimal ones. The wave operator simulates the thermal molecules moving irregularly, which enlarges the searching spaces and increases the population diversity and global searching ability. Experimental results indicate that KMTOA prevails over other algorithms in the robustness, solution quality, population diversity and convergence speed.

This paper presented a new multiscale finite element method for mechanical analysis of irregular porous materials. Realization of the proposed approach requires synergy between a hierarchical geometric model and a mechanical model for local material properties. The geometric model can represent intermediate scales and facilitates continuous bi-directional transition between macro-and micro-scales, while the mechanical model preserves the effective material properties for each scale.

Star copolymers of ε-caprolactone and L-lactide (ε-CL/L-LA) were synthesized with different compositions in the presence of pentaerythritol and using stannous octoate as catalyst. The copolymers were characterized by1H NMR spectra analysis and then blown into films in a single-screw extruder. The mechanical properties study show that the copolymers differed widely in their elongation at break and tensile strength according to the ratio of monomers and pentaerythritol in the copolymerization. The tensile strength of the films deriving from extrusion is much higher than that obtained through solvent volatilization.

The poly (lactide-co-trimethylene carbonate) copolymers are prepared by ring opening polymerization and catalyzed by SnOct and their films are prepared by blow molding. The 1HNMR study demonstrates that PLA-PTMC copolymers were successfully obtained and the graft way is A-B model. The water vapor permeability (WVP) of the films decreases with the increasing TMC content due to the formation of denser structure. The mechanical measurement reveals that the tensile strength of blown films has been declined with the increasing TMC content, but the elongation at break is improved and the tensile strength can be satisfied for the requirement of film product. Therefore, the copolymer film will be great prospect in the application of food and beverage packing.

Due to the complex relations among the various factors, the nonlinear calculation of aircraft fuel consumption is very difficult. The purpose of this paper is to present a simplified method to estimate aircraft fuel consumption using a novel particle swarm neural network. Fuel consumption information obtained directly from QAR recorded flight data is trained by the neural network. The method can avoid the high cost of flight testing and wind tunnel testing. An improved particle swarm optimization algorithm embeds neural network topology to replace the network BP learning algorithm. The experimental results demonstrate that the proposed method integrates a new particle swarm neural network system, and significantly improves the system's learning ability and prediction of evolutionary effects.

The technology of the acidification is adopted to prepare arsenic trioxide (As2O3). With a concentration of 98% of concentrated sulfuric acid and Orpiment made into a certain ratio of the slurry suspension. Arsenic trioxide’s content is 99.94%, extraction yield can reach to 98.92%. The optimal conditions is reaction temperature at 120°Cand the reaction time in 2.5 h; the slurry ratio is less than 1/6 and particle size is less than 0.080 mm.

With the development of industrial production and the improvement people's living standards, all kinds of discharged wastewater cause serious pollution for nitrogen and phosphorus.In this study, the water of Dianchi lake was treated by Ultrasonic – flocculation. The results show ultrasound-flocculation sedimentation is better than only flocculation sedimentation in removing the total phosphorus, total nitrogen and reducing COD, BOD and turbidity respectively increased 16.19%, 12.71%, 9.1%, 20%, 18.3%.

The LiCrxMn2-xO4 material used for lithium ion battery cathode material was successfully prepared by a molten-salt flameless combustion synthesis method which used the LiNO3, LiAc•2H2O, Mn(NO3)2, MnAc2•4H2O as raw materials and Cr(NO3)3•9H2O as dopant. The results indicated that, the high-purity spinel LiCrxMn2-xO4was successfully prepared although including a little Mn3O4. The impurity peak intensity of Mn3O4gradually weakened until it disappeared with the increase of the amount of Cr-doped. The product was monophasic LiCrxMn2-xO4when x (Cr) ≥ 0.1. It can be found that with Cr doped, the aggregation of the sample decreased. The structural stability, electrochemical activity and reversibility of LiCrxMn2-xO4was better than that of pristine LiMn2O4. The discharge capacity and capacity retention had been improved. The LiCr0.02Mn1.98O4had the highest initial capacity of 120.7 mAh•g-1and the capacity retention was 78.5% after 40 cycles.

Phosphogypsum is the gypsum as a byproduct of the processing of phosphate ore into fertilizer with sulfuric acid. It’s main components is CaSO4. Circulating fluidized bed(CFB) is the best reactor. In this paper the characteristics of phosphogypsum decomposition were analyzed via CFB reaction in cold test. And applied quantity of wind and bed material influenced bed pressure and the quantity of solides and solids concentration.

LiMn2O4 cathode materials were successfully prepared by solid-state combustion synthesis with the lithium carbonate and the manganese carbonate as raw materials and the citric acid as fuel. The effect of citric acid on composition, microstructure and electrochemical properties of LiMn2O4 cathode materials was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) and galvanostatic charge-discharge test. The results indicated that a pure phase of LiMn2O4 was prepared at the product with 5 wt% citric acid. However, an impure phase of Mn3O4 was found at other products. The crystal size distribution was more uniform at the higher content of citric acid. The products with 5 wt% and 10 wt% citric acid, the cubic structure morphologies of which were more prominent, and the capacities of which were higher than that of bare LiMn2O4 product. Their initial discharge specific capacities were 119.6 mAh•g-1 and 114.0 mAh•g-1, and their capacity retention ratios after 40 cycles were 85.0% and 87.7%, respectively.

The spinel Mg-doped LiMn2-xMgxO4（0≤x≤0.10）lithium ion cathode material was prepared by LiNO3, Mn(Ac)2.4H2O and Mg(Ac)2.4H2O by a low-temperature flameless solution combustion at 400°C, and HNO3 was used as oxidant. The results showed that the crystallinity of prepared material was superior to the pure LiMn2O4, and this method was better than traditional solid-state method. The particle sizes of the Mg-doped spinel LiMn2-xMgxO4 decreased with the increase of Mg doping, and the particle sizes were 50 to 90 nm; the crystal lattice interface was clear. The original capacities of Mg-doped were lower than that of undoped LiMn2O4 (109.2 mAh/g) excepts for x(Mg)=0.04, original capacity of which was 128mAh/g. However, the rentions of all the doped spinels were higher than that of undoped spinel.

The zinc coating was immersed into a rare-earth conversion coating treatment liquid, with Ce(NO3)3•6H2O as the main salt and 30% H2O2 as the oxidizing agent. A Ce-H2O series potential-pH diagram and a Zn-H2O series potential-pH diagram were then established by calculating the maximum pH value obtainable on the interface. Therefore, the cerium conversion coating was deduced to be composed of ZnO, CeO2, Ce2O3, Ce(OH)3, and Ce(OH)4, In addition, XPS and XRD was used to analyze the appearance and phase of the cerium-based conversion coating in terms of the rare-earth conversion coating obtained in the experiment. The results reveal that the cerium-based conversion coating is the compound coating mainly consists of ZnO, CeO2, Ce2O3, Ce(OH)3 and Ce(OH)4, which is in line with the theoretical analysis.

This paper aims to study the impact of cerium on the corrosion resistance of zinc coating in 5% NaCl solution. Based on the immersing experiment, electrochemistry was used to measure the electrochemical parameters when comparing the zinc coating’s corrosion resistance with that of zinc coating with an additional cerium conversion coating. SEM and XRD were adopted to analyze the appearance and phases of corrosion products of this cerium conversion coating, and to probe the impact of cerium on the corrosion behavior of zinc coating in Cl- environment. The results showed that cerium conversion coating formed on the zinc coating effectively increased the zinc’s corrosion resistance. By contrast, models of conversion coating with lower cerium content poorly protected the substrate, resulting in easy erosion of the zinc coating in Cl- environment.

Immersion precipitation is one of the commonly used methods in preparing polyvinylidene fluoride membrane (PVDF) membrane. Using this method, the membrane structure is easily controlled and the operation is very simple. This paper summarized the mechanism and preparation methods of PVDF as well as researching the effects of membrane-forming factors such as ingredient of solvents and non-solvents, temperature and additives etc. on the structure and function of PVDF membrane. Applying modification on PVDF membrane can improve its hydrophilicity and anti-fouling properties, of which blending modification is expected to be a hotspot of study in future. Adding catalytic agent into PVDF can generate catalytic membrane, which offers a researching direction for preparing multi-functional PVDF membrane. Finally, brief comments are made on the improvement of membrane pore structure and problem of singleness of blending materials.

The deformation of the prestress frame of open-die forging hydraulic press is studied in the paper. Firstly, the computing formula of true prestressing force of frame is deduced, and then the finite element model of prestress frame is established. With the model, the deformation of prestress frame is studied when the press works under different operating modes including upsetting, elongating and saddle forging and the effect of different operating modes on the deformation are revealed. The main achievements include: The true prestressing force of frame can be gained with nominal prestressing force, section area and working length of tension rods, section area and length of columns. Under prestress, the stress of the field of up beam and down beam acted by the axial force of tension rods and columns is bigger, that of the other field is very small. Under working loads, up beam and down beam tend to open out, tension rods and columns tend to bend in, and the bending effect cause the stress of inner field of tension rods bigger than that of outer field and the stress of inner field of columns smaller than that of outer field. The deformation of down beam under saddle forging is different with that under upsetting and elongating. The stress of center field of down beam under upsetting and elongating is higher and that of front and back field of down beam under upsetting is higher. The main achievements of the study are useful to design the prestress frame of open-die forging hydraulic press and the research method can be used to study the prestress frame of other equipments.

A new heterogeneous catalyst Fe-Mn/GAC (iron and manganese were loaded into activated carbon particles) was prepared, which had a better catalytic reactivity to decompose H2O2 compared with Fe/GAC and Mn/GAC. The removal rate of Orange IV increased more than 10% with this catalyst compared with Fe/GAC and Mn/GAC. The effect of the initial concentration of H2O2, the initial dye concentration, the initial catalyst concentration, the initial pH and temperature on the reaction rate constant were also studied. The activated energy for Fe-Mn/GAC catalyzed oxidation of the dye was determined to be 66.16KJ/mol. Reuse of catalyst did not decrease the removal rate of Orange IV. The tert-butanol experiment indicated that there were not only hydroxyl radicals but also other active species in the system.

A new heterogeneous Fenton-like catalyst of Fe/S/GAC was prepared by granular activated carbon (GAC) soaked in solution of (NH4)2S2O8 and Fe(NO3)3. The effect of the concentration of (NH4)2S2O8 , Fe(NO3)3, drying temperature and different catalysts on the catalytic reactivity of catalyst was discussed. The removal rate of Orange IV was used to express the catalytic reactivity of the catalyst. The prepared catalysts were characterized by X-ray diffraction (XRD), specific surface area (BET) and scanning electron microscopy (SEM). The removal rate of Orange IV followed second-order kinetics. The catalyst of Fe/S/GAC has higher catalytic activity than that of Fe/GAC.

The FE model of the pretightening assembly moving beam of open-die forging hydraulic press is built with FE simulation software ABAQUS in the study. With the FE model, the force status of pretightening assembly moving beam is studied. Then the pretightening force of assembly moving beam is further studied and the computing method of pretightening force is given. The main achievements of the study include: Under pretightening, the stress of main moving beam is very low and that of guild sleeves is also lower than the allowable stress. Under center loading, the stress of the center field of main moving beam is higher and that of guild sleeves is almost same to that of pretightening. Under eccentric loading, the stress of same deviation field of main moving beam is higher and the effect of pretightening force on the stress of main moving beam is very small. The stress distribution of guild sleeves with different pretightening force is same and the effect of pretightening force on its strength is very low. The pretightening force of tension rod can be computed with the force of press, the allowable eccentric value of the workpiece, the distance between up guild section and down guild section of guild sleeve and the quantity of tension rods. The results of the study are very useful to design and install the pretightening assembly moving beam of open-die forging hydraulic press.

Reaction injection molding process of phenolic foam sandwich plate was introduced in order to resolve the difficulties in repetitive continuous manufacturing process of such product. The phenolic foam produced here have uniform pore diameter, good fireproof property and there need not any glue between phenolic foam and color steel plate which could make it a potential building material instead of polysterol sandwich plate.

The influences of space velocity, temperature and copper content in Cu-MCM41 catalysts with high copper content up to 26.1wt.% on the catalytic activity in NO reduction by CO were investigated. Results indicated 1) the prepared materials exhibited excellent activity for NO+CO reaction, 2) the catalytic activities increased with the copper contents and NO can be fully converted to N2 for the catalyst containing 26.1wt.% Cu with the space velocity of 30,000ml•g-1•h-1 at 673K to 823K, 3) catalytic activities of the original catalysts with the temperature were volcano-type curves, however, it increased straightly with temperature over the catalysts after reacting at 723K for 1h, which might be attributed to the different active sites and different catalytic mechanisms of the catalysts at lower and higher temperature, 4) the catalytic activity did not decline after reacting at 723K for 20 h in a reactant gas mixture of 33,000 ppm NO and 66,000 ppm CO.

Solid super acid (S2O82-/FexOy-CuOx) was prepared and used as a heterogeneous Fenton-like catalyst to decompose H2O2for the degradation of refractory dye Orange IV in water. The factors that affected the degradation of Orange IV were discussed in this heterogeneous Fenton-like system. The catalytic activity of S2O82-/FexOy-CuOxwas evaluated by the degradation of Orange IV and the decomposition of H2O2. The results show that the catalyst S2O82-/FexOy-CuOxhas a good catalytic activity. The reaction follows pseudo-first-order kinetics; the reaction rate constant has a good relationship with the concentration of H2O2. The degradation rate of Orange IV and the decomposition rate of H2O2increase with the increase of temperature and the dosage of catalyst whereas it decreases with the increase of the initial concentration of Orange IV and the initial pH.

A new Fenton-like catalyst was prepared to degrade Orange IV in water by catalytic decomposition of H2O2. The optimal preparation conditions were discussed. The catalytic activity of catalyst was evaluated by the degradation of Orange IV and the decomposition of H2O2. The results show that solid super acid (S2O82-/FexOy) soaked in (NH4)2S2O8 is the most effective catalyst among the synthesized iron oxides soaked in other oxidants. The optimal conditions for solid super acid preparation are calcined at 500 for 2 h in the air.

A new kind of PVDF/Fe3+/Cu2+ catalytic membrane was prepared and used as a heterogeneous Fenton-like catalyst to degrade Orange IV in the presence of H2O2. The effect of initial concentration of H2O2 and Orange IV, initial pH, reaction temperature and catalyst dosage on the reaction rate was studied. The results show that the higher the concentration of H2O2, the faster the reaction rate is. The reaction rate increased with the increase of temperature with the activation energy 30.18KJ•mol-1. The PVDF/Fe3+/Cu2+ catalytic membrane can effectively decolorize Orange IV in the pH range of 3.1-5.3. The decolorization rate of Orange IV decreased with the increase of initial concentration of Orange IV. The decolorization rate of Orange IV increased with the increase of dosage of catalyst. The reactive intermediates for this reaction is HO• based on t-butanol experiments.

Solid super acid(S2O82-/FexOy-CuOx)was prepared and used as a Fenton-like catalyst to decompose H2O2 for the removal of orgnanic pollutants in water. The catalytic activity of S2O82-/FexOy-CuOx was evaluated by the degradation of organic pollutants and the decomposition of H2O2. The results show that the catalytic activity of S2O82-/FexOy-CuOx to decompose H2O2 is higher than that of S2O82-/FexOy. The reason for this may be due to the dissolved of Fe2+ from the S2O82-/FexOy-CuOx, and the concentration of dissolved of Fe2+ is proportional to the concentration of organic pollutants in water. The degradation rate of phenol by the catalyst of S2O82-/FexOy-CuOx is obviously higher than that by the catalyst of Fe2+ ion under the same conditions. BET measurements show that the surface area of S2O82-/FexOy-CuOx is larger than that of S2O82-/FexOy.

A new heterogeneous PVDF/Fe3+-TiO2 catalytic membrane is prepared by sol-gel method, which had a well catalytic activity to decompose H2O2. The effect of initial pH, e initial concentration of H2O2 and Orange IV, temperature, and membrane area on the reaction rate is discussed. The PVDF/Fe3+-TiO2 catalytic membrane can effectively decolorize Orange IV in the pH range of 3.0-5.0. The optimal concentration of H2O2 is 15mmol/L. The reaction rate constant is proportional to the initial concentrations of Orange IV. The higher the temperature, the faster the reaction rate is, this reaction follows pseudo-first-order kinetics with activation energy of 1.54kJ/mol. Reuse of catalyst did not decrease the removal rate of Orange IV. The experiments of t-butanol, EDTA and XPS measurement showed that •OH, the electron hole and the ferryl are all the reactive species in the degradation of Orange IV.

In order to explore a new kind of high anti-corrosion and environmentally benign materials to protect steel, zinc-silica composite coatings were prepared by plating technique. In this paper, experiments on electrodeposited zinc-silica composite coatings are reported, effects of cathodic current density, agitation, additive, anode number, space between anode and cathode on the appearance of coatings are discussed, composition and property of zinc-silica composite coatings are investigated. The electrolyte composition and operating conditions are: ZnCl2 80 g/L, KCl 220 g/L, additive 10 ml/L, SiO2 2~3 g/L, pH 4~5, current density 140~180 A/m2, temperature 15~35°C, 20~30 cm space between anodes and cathodes, once plating time is 60 min.The content of silica in coatings is 0.47~0.56%(mass), the thickness of coatings is 20~23 μm, and the time of composite coatings appearing red rust in neutral salt spray test(NSS) keeps more than 410 h. During the experiment lasting for 30 days, pH value and composition of the electrolyte and deposition speed of coatings all keep relatively stable. Further more, this composite plating technique can reach the first National Entironment Standard(GB 8978–1996). All the results show that zinc-silica composite coatings with no chromate treatment have better corrosion resistance than zinc coatings, stability of this composite plating technique is satisfactory, maintenance operation is convenient, and the plating process is innocuous and safe, so this technique will undoubtedly has a great future in application.