Xian Hua Li

One-step fabrication and high photocatalytic activity of porous graphitic carbon nitride/graphene oxide hybrid by direct polymerization of cyanamide without templates

Graphene oxide modified porous g-C3N4 (porous g-C3N4/GO) had been synthesized by means of one-step calcination of cyanamide for efficient photocatalysis under visible light irradiation (λ > 400 nm). We expect that the photocatalytic activity of this hybrid photocatalyst could be enhanced by the efficient visible light absorption due to the porous structure and efficient photo generated charge separation at the heterojunction formed between porous g-C3N4 and GO. Scanning electron microscopy (SEM) images demonstrated that the as prepared photocatalyst is composed of GO and porous g-C3N4. The UV-vis diffuse reflectance spectrum shows that optical absorption of porous g-C3N4/GO is more intensive than for pristine g-C3N4. The enhanced generation of photocurrent under visible light irradiation (λ > 400 nm) is observed for the porous g-C3N4/GO. The results of photocatalytic experiments reveal that the pseudofirst-order kinetic constant of photocatalytic degradation of methylene blue (MB) using the porous g-C3N4/GO is 6 times higher than that of pristine g-C3N4.

Significantly improving the performance and dispersion morphology of porous g-C3N4/PANI composites by an interfacial polymerization method

Abstract Polyaniline (PANI) nanorods grown on layered porous graphitic carbon nitride (porous g-C3N4) sheets (porous g-C3N4/PANI) were successfully synthesized by interfacial polymerization of aniline monomers in the presence of porous g-C3N4 sheets. The experimental results suggest that porous g-C3N4 obtained a good dispersion with intercalated and exfoliated nanostructure and interfacial adhesion in PANI, which improved the thermal stability and photocatalytic activity of the porous g-C3N4/PANI composites.

Numerical Simulation of the Gear Flowmeter Reveal Based on Pumplinx

The oil spill will directly affect the measuring accuracy of the gear flowmeter, so use the computational fluid dynamics software to calculate the leakage regulation of the internal gear flowmeter is one of the important things. Based on Pumplinx, when the end clearances of the gear flowmeter were 0um, 10um, 20um, 30um, 40um and 50um, the corresponding numerical analysis of spillage was carried out. From the results of numerical analysis, with the increase of the end clearance, the leakage amplification will also increase. In practical work, we should control the end clearance of gear flowmeter strictly while the gear works normally.

Self-assembled g-C3N4 nanosheets with Ca2+ linkage

Graphitic carbon nitride nanosheets (g-C3N4 NS) are an important material with many promising practical applications. However, construction of g-C3N4 NS self-assembled structures with three dimensions (3D) has never been realized. Here, we prepared a self-assembled g-C3N4 NS microgel (SGM) via hydrothermal treatment of g-C3N4 NS in the presence of Ca2+. The size and microstructure of SGM can be controlled by the concentration of Ca2+. The obtained SGM also exhibits a temperature response, improved optical properties and high photocatalytic activity.

A novel 3D carbon linked by uniform size nanospheres

Abstract3D carbon linked by uniform sized nanospheres was successfully prepared by hydrothermal carbonization method. It is found that the increasing reaction temperature and extending reaction times have a similar effect on the morphology of the products, which could evolve from nanospheres to 3D carbon linked by nanospheres or layered structure. The final chemical structure of the products can be switched from a carbon rich in oxygen containing functional groups type to a carbon network of extensive aromatic domain.

Human Physiological Signal Recognition Based on Piezoelectric Impedance Technique

In order to verify whether the piezoelectric impedance technology can be applied to detect the physiological signals of human body, the principle of piezoelectric coupling impedance theory and piezoelectric impedance technology using for human physiological signal detection was introduced in this paper. With an experiment platform set up, detection experiments based on the piezoelectric impedance technology were created. And the experimental1 was improved to avoid the influence of man-made factors on experiment result. Two methods were used to deal with the experimental data. The results show that the piezoelectric impedance technique can be applied to identify the human body physiological signal, and offers a totally new idea to detect the physiological signals of human body.

Numerical Studies of Reinforced Concrete Beam Damage Detection Based on the Piezoelectric Impedance and Neural Network Technology

Aiming at the problem of reinforced concrete structure crack damage detection, an algorithm of crack damage monitoring based on the piezoelectric impedance technology was presented in this paper. With a piezoelectric coupling beam model was established, the electrical impedance equation of piezoelectric coupling beam was derived. The finite element model of reinforced concrete beam pasting with piezoelectric ceramic piece was established. The effect of different crack depth on the electrical impedance of coupling beam was analyzed. The results show that with the increase of crack depth, impedance peak decreases, spectrum shift to the left; neural network technology data processing method was used to the location identification of reinforced concrete beam crack depth. It proves that the piezoelectric impedance technology can successfully identify the degree of reinforced concrete beam damage to some extent.

The Research of Flow Meter Dynamic Simulation Test

The flow signal is one of the main parameters of hydraulic system monitoring. Since the majority of fault features can be shown by dynamic traffic signal, The study of dynamic traffic signal has very important significance on the evaluation of the performance of hydraulic element and characteristics of the hydraulic system. In this paper, the flow meter dynamic signal was simulated by the self-designed test-bed called multi-functional gear flow meter speed detection test-bed. The experiment indicates that the using PLC control of inverter and motor can realize high frequency dynamic oscillating of gear, oscillation frequency can reach 2Hz above. If the accuracy is met with, flow meter dynamic characteristic can reach 10Hz through the test-bed simulation, which provides the basis of theory and experiment for the real-time dynamic flow characteristics test.

The Simulation Research of Dynamic Flow Based on the Bypass Method

The flow rate in high pressure hydraulic system is greatly affected when flow meter is inserted in the system. A method was proposed that was by measuring the lateral pipe flow instead of directly measuring system of main flow. According to this method, simulation model was set up based on software. And the influence of the flow distribution relationship between main and side oil-way by the change of relief valve. Theoretical studies show that the measurement method is feasible.

Analysis of pipeline dynamic flow signal coupling in hydraulic system

The dynamic measurement of the high pressure side flow in hydraulic system is still one of the important and difficult problems in hydraulic test technique. In order to solve the dynamic coupling mechanism between main and bypass oil-way fluid flow signals in the bypass flow measurement method, hydraulic system software was used to analysis the problem in this paper, the dynamic coupling relationship between main and bypass oil-way fluid flow signals were obtained. Finally verify the feasibility of the bypass flow measurement method.