The H9N2 avian influenza virus (AIV) is difficult to prevent and control because of its low pathogenicity and frequent mutation. In a previous study, the HA (hemagglutinin) protein of H9N2 was expressed in a rice endosperm reactor and prepared into a subunit vaccine to immunize chickens and mice, both of which exhibited a good immunity effect. The results of the intermediate tests of the transgenic strains (AIV-1 and AIV-3) showed that the HA gene can be stably expressed. Agronomic traits, such as plant height and number of grains, were significantly optimized in the transgenic strains. Moreover, no exogenous HA genes were found in the leaves of the weeds, and it was initially determined that there was no risk of gene drift. This study provides key technical support for the commercialization of plant subunit vaccines for avian influenza viruses.
We report for the first time a coherent red radiation at 689 nm by intracavity sum-frequency generation of the 1319- and 1444-nm laser-lines of two Nd:YAG lasers. Using type-II critical phase matching KTP crystal, 689-nm red laser was obtained by 1444- and 1319-nm intra-cavity sum-frequency mixing, and output power of 156 mW was obtained. At the output power level of 156 mW, the output power stability is better than 5.0% and laser beam quality M 2 factor is 1.23.
In order to improve the quality of colorful offset printing and know the process of ink transferring, this paper adopts the method of theoretical analysis and experiment, the velocity and pressure of the ink flow field are analyzed when the rubber roller deforms and the two rollers rotate, and the effective ink layer thickness is extracted, then the ink transferring rate can be got. The rubber roller’s deformation and ink transferring rate under different conditions are got, and factors, such as rotation velocity, deformation of rubber roller, ink layer thickness between two rollers, which affect the ink flow and transferring rate are analyzed.
To date, incineration is the main method of municipal solid waste (MSW) disposal. Fly ash and bottom ash (BA) are generated in large amounts from municipal
The influence of Cl- and Ca2+ on the naturally growing passive film of a new, alloyed stainless steel with 10% Cr and 0% Ni was investigated by electrochemical impedance spectroscopy, Mott-Schottky curves, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The results showed that Ca2+ had an inhabitation effect on passive film dissolution and that Cl- did not penetrate into the passive film, probably due to adsorption onto lower-energy oxygen vacancies and to the inhabitation effect of the space charge layer with a strong electric field. Local sites in the passive film thickened and the outer layer turned into an amorphous, porous structure due to its structural integrity. Additionally, the passive film remained passive in concrete.
With the current energy environment background and development of the electrification of the automotive industry, a comprehensive economic indicator, in which the battery aging is further considered on the basis of conventional energy consumption, is proposed to research the energy optimization problem of two-speed electric vehicles. Firstly, a battery life model that adapts to vehicles under high dynamic conditions is introduced. Then, the speed optimal control problem of the two-speed electric vehicles in the acceleration–cruise–deceleration process is established and solved. Finally, the simulation results of two different performance indicators are contrasted and the performance improvement of the two-speed gearbox to the electric vehicles is analyzed. The simulation results under various working scenarios and driving cycles demonstrate that, compared with the conventional economic indicator considering the energy consumption only, the proposed economic indicator can significantly improve the battery life. In addition, it can also be seen that, compared with the one-speed electric vehicles, the application of a two-speed gearbox provides better performance from the aspects of battery aging saving and energy consumption.
Siliceous and ferro-siliceous sacrificial concrete (SC) are designed to reduce the leakage potential of radioactive materials in case of severe nuclear accidents. This paper presents an investigation on thermal behavior and damage evolution of SCs subjected to high temperatures. In this study, the microstructure, porosity, high-temperature integrity, mass loss, compressive strength, splitting tensile strength, and thermal diffusivity of SCs were investigated at different elevated temperatures up to 1000°C. Using ultrasonic testing technique, variations of ultrasonic pulse velocity (UPV) propagation in SCs exposed to different high temperatures were obtained. According to definition of damage, a relationship between damage of SC and UPV was derived, eventually concluding a correlation between the damage of SC and high temperatures that SC subjected to. It was found that, (1) the SCs designed have very good performances, and are suitable for use in practice; (2) with temperature increasing, the thermal diffusivity of SCs decreases continually, and the damage evolution of SCs can be described by a Weibull distribution model.
The safety of nuclear power plant can be improved via core catcher, and cement-based sacrificial materials are widely used in most core catchers because of their simple construction process and the low manufacturing cost. This paper carried out a preliminary investigation to explore the feasibility of using strontium ferrite to prepare cement-based sacrificial materials. The effects of strontium ferrite on the room temperature and high temperature properties of cement mortar were systematically studied in the work. In addition, the damage evolution of cement mortar containing strontium ferrite subjected to elevated temperatures was also identified according to the damage mechanics theory. It was found that, (1) the addition of strontium ferrite led to the deterioration of the mechanical properties, microstructure and pore structure of cement mortar; (2) it was feasible to prepare cement-based sacrificial materials containing strontium ferrite that met the requirements on basic properties like mechanical properties, free water content, volume stability, and the high temperature integrity by controlling the content of strontium ferrite; (3) the correlation between the internal damage of cement mortar and the temperature could be described by Weibull Distribution Model, which provided a basis for the identification and evaluation of serious nuclear power accidents.
Progress in the field of nanomaterials presents an opportunity to improve the performance of cementitious composites via graphene or its derivatives. This paper presents an experimental study on mechanical and thermal properties of sacrificial concrete without and with graphene sulfonate nanosheets (GSNSs) during high temperature exposure. The microstructure, porosity, mechanical strengths, thermal analysis, coefficient of thermal expansion, thermal diffusivity and ablation behaviour of sacrificial concrete during exposure to various temperatures up to 1000°C were comprehensively investigated. Two new experimental apparatuses were developed and used to measure mechanical strengths of sacrificial concrete at elevated temperatures. It was found that the compressive strength, splitting tensile strength, thermal diffusivity and decomposition enthalpy of sacrificial concrete were increased by 12.98–25.36%, 8.66–34.38%, 25.00–103.23% and 4.23% respectively when adding 0.1wt% GSNSs, while the porosity and ablation velocity of sacrificial concrete were reduced by 3.01–6.99% and 4.14% respectively due to the incorporation of GSNSs.
Ultra-high-performance concrete (UHPC) has promising applications in civil engineering. However, the elastic modulus of UHPC is relatively low compared with its compressive strength, which may result in insufficient stiffness in service. This work was carried out to explore the feasibility of producing UHPC with high elastic modulus by nano-Al2O3 (NA). Based on particle densely packing theory, the initial mixture of UHPC was designed via the modified Andreasen and Andersen model. An experimental investigation was conducted to systematically examine the effects of NA on different properties of UHPC, including its fluidity, mechanical properties, durability, and microstructure. It was found that: (1) Compared with UHPC without NA, the flexural strength, compressive strength, and elastic modulus of UHPC were improved by 7.38-16.87%, 4.08-20.58%, and 2.89-14.08%, respectively, because of the incorporation of NA; (2) the addition of NA had a prohibiting impact on the threshold pore diameter and porosity of UHPC, which suggested that NA could be conducive to its pore structure; (3) the incorporation of NA led to a decline of 2.9-11.76% in the dry shrinkage of UHPC, which suggested that incorporating NA in a proper amount could reduce the risk of cracking and alleviate the dry shrinkage of UHPC; (4) the optimal amount of NA in UHPC was 1.0%, considering the effects of NA on workability, mechanical properties, microstructure, and the durability of UHPC.
Ultra-high-performance concrete (UHPC) has been used as an advanced construction material in civil engineering because of its excellent mechanical properties and durability. However, with the depletion of the raw material (river sand) used for preparing UHPC, it is imperative to find a replacement material. Recycled sand is an alternative raw material for preparing UHPC, but it degrades the performance. In this study, we investigated the use of graphene oxide (GO) as an additive for enhancing the properties of UHPC prepared from recycled sand. The primary objective was to investigate the effects of GO on the mechanical properties and durability of the UHPC at different concentrations. Additionally, the impact of the GO additive on the microstructure of the UHPC prepared from recycled sand was analysed at different mixing concentrations. The addition of GO resulted in the following: (1) The porosity of the UHPC prepared from recycled sand was reduced by 4.45–11.35%; (2) the compressive strength, flexural strength, splitting tensile strength, and elastic modulus of the UHPC prepared from recycled sand were enhanced by 8.24–16.83%, 11.26–26.62%, 15.63–29.54%, and 5.84–12.25%, respectively; (3) the resistance of the UHPC to penetration of chloride ions increased, and the freeze–thaw resistance improved; (4) the optimum mixing concentration of GO in the UHPC was determined to be 0.05 wt.%, according to a comprehensive analysis of its effects on the microstructure, mechanical properties, and durability of the UHPC. The findings of this study provide important guidance for the utilisation of recycled sand resources.
Schwarz's form is fundamental and effective in constructing Liapuaov functions, in proving the Hurwitz criterion, and in evaluating performance measures in system analysis. However, the procedures developed thus far for obtaining the Schwarz form are complicated. This paper establishes a basic transformation matrix by which a phase-variable form is easily converted into a Schwarz form. When the new transformation matrix is used, Kalman-Bertram's Liapunov function is simplified and Ralston's symmetric matrix formulation of the Hurwitz criterion is derived in a completely different but much more sophisticated way. Finally, to the authors' knowledge, this is the first time that practical use has been made of the second, third, etc., columns of Routh's array.
The hard roller and soft roller are alternately arranged in the inking system of offset press. The ink vibrator is a hard roller which transmits the motion to the ink distributing roller. In order to analyze the motion mechanism of the ink roller, a model of an ink distributing roller and an ink vibrator is built up by using the software ANSYS. After the simulation of the motion, the force on the contact area of the ink distributing roller and the rotation speed of both rollers are analyzed. The result is that the ink distributing roller rotates with tangential force on the contact area and this force increases together with the rotation speed. When the two rollers rotate, the tangential elastic deformation is caused by the tangential force on contact area, and the radial deformation of the ink distributing roller is caused by the pressure. It leads to a relative sliding of the two rollers, which is mainly influenced by the rotation speed of ink vibrator and the radial deformation of ink distributing roller. Meanwhile, to verify the accuracy of the analysis, the rotation speed of the two rollers and the deformation of the ink distributing roller have been measured on a printability tester and then compared with the results of simulation. The analysis of the motion mechanism is very important to the study of printing color quality control.
Polycarboxylate superplasticizer (PCE) is an important part of improving the overall performance of concrete. However, its synthetic raw materials are overly dependent on petrochemical products, and it also causes problems such as environmental pollution. With the development of the building material industry, the demand for petrochemical resources required for synthetic water-reducing agents will increase rapidly. Therefore, there is an urgent need to transition the synthetic raw materials of PCE from petrochemicals to biomass materials to reduce the consumption of nonrenewable resources as well as the burden on the environment. Biomass materials are inexpensive, readily available and renewable. Utilizing biomass resources to develop good-performing water-reducing agents can reduce the consumption of fossil resources. This is conducive to carbon emission reduction in the concrete material industry. In addition, it promotes the high-value utilization of biomass resources. Therefore, in this study, a biomass polyether monomer, acryloyl hydroxyethyl cellulose (AHEC), was synthesized from cellulose via the reaction route of ethylene oxide (EO) etherification and acrylic acid (AA) esterification. Biomass polycarboxylate superplasticizers (PCE-Cs) were synthesized through free radical polymerization by substituting AHEC for a portion of the frequently utilized polyether monomer isopentenyl polyoxyethylene ether (TPEG). This study primarily focused on the properties of PCE-Cs in relation to cement. The findings of this study indicated that the synthesized PCE-C5 at a dosing of 0.4% (expressed as mass fraction of cement) when the AHEC substitution ratio was 5% achieved good water reduction properties and significant delays. With the same fluidity, PCE-C5 could enhance the mechanical strength of cement mortar by 30% to 40%. This study utilized green and low-carbon biomass resources to develop synthetic raw materials for water-reducing agents, which exhibited effective water-reducing performance and enhanced the utilization rate of biomass resources, demonstrating significant application value.
We report the generation of a green laser at 543 nm by intracavity frequency doubling of the continuous-wave (cw) laser operation of a 1086 nm Nd:YVO4 laser under 888 nm diode pumping into the emitting level 4F3/2. An LiB3O5 (LBO) crystal, cut for critical type I phase matching at room temperature, is used for the laser second-harmonic generation. At an incident pump power of 17.8 W, as high as 4.53 W cw output power at 543 nm is achieved. The optical-to-optical conversion efficiency is up to 25.4%, and the fluctuation of the green output power is better than 2.3% in a 30 min period.
In this study, the pitting behaviour of a new corrosion-resistant alloy steel (CR) is compared to that of low-carbon steel (LC) in a simulated concrete pore solution with a chloride concentration of 5 mol/L. The electrochemical behaviour of the bars was characterised using linear polarisation resistance (LPR) and electrochemical impedance spectroscopy (EIS). The pitting profiles were detected by reflective digital holographic microscopy (DHM), scanning electron microscopy (SEM), and the chemical components produced in the pitting process were analysed by X-ray energy dispersive spectroscopy (EDS). The results show that the CR bars have a higher resistance to pitting corrosion than the LC bars. This is primarily because of the periodic occurrence of metastable pitting during pitting development. Compared to the pitting process in the LC bars, the pitting depth grows slowly in the CR bars, which greatly reduces the risk of pitting. The possible reason for this result is that the capability of the CR bars to heal the passivation film helps to restore the metastable pits to the passivation state.
