Search

Composite cathodes composed of Li3V2(PO4)3 and multiwall carbon nanotubes (MWCNTs) for high-performance Li-ion batteries were synthesized via a fast sol-gel method, using ascorbic acid as reductive reagent and carbon source, while using MWCNTs as high conductivity modifier. Due to the synergistic effect between functional groups of MWCNTs and reductive functionality of ascorbic acid, MWCNTs were uniformly embedded into Li3V2(PO4)3@C for constructing a unique three-dimensional architecture with excellent electronic and ionic conductivity to achieve superior high rate performance. When tested as a cathode material in lithium-ion batteries, the optimal Li3V2(PO4)3@MWCNTs@C composite can deliver 123.5 mAh g−1 of specific capacity at 5 C and maintain a capacity retention of 96.3% after 300 cycles; even after cycled at 15-C rate for 300 times, it still possesses 90.2 mAh g−1 of specific capacity, demonstrating a great promising result for cathode alternative in high-power lithium-ion batteries.

Bamboo as the raw material is carbonized to prepare high specific surface area activated carbon by microwave heating under nitrogen atmosphere in our present work. Influences of activation agents on the preparation of activated carbon are studied. The results show that activation agents have a significant influence on the preparation of activated carbon. Under the heating time of 15 min, the adsorption capacity of the activated carbon prepared utilizing KOH as activation agent is the best. When the KOH/C ratio is 4, the iodine number and yield of activated carbon are 2298 mg/g and 39.82%, respectively. The BET specific surface area, total pore volume and average pore diameter of activated carbon are 3441 m2/g, 2.093 ml/g and 2.434 nm, respectively. The micropore volume of 1.304 ml/g is 62.30% of total pore volume, indicating that the activated carbon is microporous activated carbon.

This paper presents a solution to satisfy the increasing requirements for secure medical image transmission and storage over public networks. The proposed scheme can simultaneously encrypt and compress the medical image using compressive sensing (CS) and pixel swapping based permutation approach. In the CS phase, the plain image is compressed and encrypted by chaos-based Bernoulli measurement matrix, which is generated under the control of the introduced Chebyshev map. The quantized measurements are then encrypted by permutation-diffusion type chaotic cipher for the second level protection. Simulations and extensive security analyses have been performed. The results demonstrate that at a large scale of compression ratio the proposed cryptosystem can provide satisfactory security level and reconstruction quality.

Nowadays, the increasing demand for telemedicine services has raised interest in the real-time medical image protection literatures. In this paper, we evaluate the security of an efficient and secure medical image protection scheme recently proposed (Fu et al., 2013). It is found that this scheme can be successfully broken by launching chosen-plaintext attacks. Improvement is subsequently developed for promoting the security and efficiency performance. Extensive security analyses and experimental results both indicate that the improved scheme can well address the security flaws and advance the speed performance of the original one.

Electro-hydraulic power steering system (EHPS) assistance characteristic curves are generally linear, folded line and curve type. The folded line type combines the advantages of linear and curve type assistance characteristic, but the slope of the characteristic curve changes suddenly, which have an impact on the driver, leading to potentially dangerous. In view of existing problem, the article studies deeply the characteristics of the power system to apply computer simulation technology, and improves the folded line characteristic curve. The simulation analytic results show clearly that the improvements of folded line assistance characteristics curve is reasonable.

The technology that CuCl residue from Zn hydrometallurgy was dried by microwave heating was studied. The influence of the drying duration, drying temperature and material thickness on dehydration rate was investigated. The response surface methodology (RSM) technique was utilized to optimize the process conditions. The optimum conditions for drying CuCl residue have been identified to be an drying temperature of 80°C, drying duration of 11 min and material thickness of 16 mm. The optimum conditions resulted in an CuCl residue with moisture content of 4.97%, which could ensure remove chlorine of CuCl residue by microwave roasting.

Aiming at avoiding misregistration in complicated medical image registration based on SURF (Speed-Up Robust Features)-TPS (Thin-Plate Spline), we propose a novel algorithm. This method is based on SURF and human interaction method for feature extraction. Then we improve SURF-TPS and propose an algorithm named TPS-SEMISURF which obtains the deformation field by calculating the Thin-plate spline of the feature points, and finally does the medical image non-rigid registration according to the parameters. Experimental results showed that the proposed method can register medical images effectively. It has a good robustness and owns better precision and rate than traditional algorithm.

This article using AMESim and Simulink software co-simulation technology and appropriate software to establish the simulation model of the key components of the steering system, it is found the factor which affect vehicle handling and stability of steering system in the structure by analyzing the impact of various parameters on the car steering system. It is to verify the feasibility of the model and study how steering system of all kinds of main factor to influence the vehicle steering stability through Simulink and AMESim software co-simulation results cf vehicle steering stability GB experiments.

A novel method for preparation of iron oxyhydroxide materials, involving aqueous precipitation followed by microwave assisted aging is investigated. The produced materials are characterized by XRD, SEM, EDX and TEM spectroscopy and BET analysis. The materials show physical characteristics dependent on preparation procedure. The adsorptive properties of the materials for arsenic are studied by batch adsorption techniques. It is found that the rate of arsenic upload depends strongly on the degree of crystallinity of the materials. The adsorption capacity is approximately 55 mg/g. The physical characterization of the arsenic loaded adsorbents show that the adsorption process modifies the morphology of the materials. Over 4% of arsenic atoms are incorporated into the particle matrix.

Support vector machines (SVMs) are a promising type of learning machine based on structural risk minimization and statistical learning theory, which can be divided into two categories: support vector classification (SVC) machines and support vector regression machines (SVR). The basic elements and algorithms of SVR machines are discussed. As modeling and prediction methods are introduced into the experiment of microwave preparing partially stabilized zirconia (PSZ) and built the stability prediction model, the better prediction accuracy and the better fitting results are verified and analyzed. This is conducted to elucidate the good generalization performance of SVMs, specially good for dealing with nonlinear data.

A microwave carbonthermal nitridation method under the condition of nitrogen at atmospheric pressure was used to the synthesis of vanadium nitride from vanadium pentoxide and carbon black. In the present work, the effects of synthesis temperature, flowing rate of nitrogen, heating rate and soaking time on the apparent density and the nitrogen content of the microwave sintered samples were studied. The experimental data indicated that the apparent density and the nitrogen content of the microwave sinter sample was 4.1 g/cm3 and 13.8 %, respectively under the optimum conditions of flowing rate of nitrogen 50 L/h, heating rate of 6 °C/min to 1400 °C and soaking time of 50 min. The denser pellet was preferred to generated in the centre of the samples of which was beneficial to the expulsion of stoma and the diffusion of nitrogen due to the opposite temperature gradient compared with traditional heating.

The stability is a key product performance index, which can directly determine the quality of the partially stabilized zirconia (PSZ), so how to predict the stability of PSZ accurately, quickly and easily in the preparation process is very important. In this paper, a new mathematical model to predict the stability of PSZ prepared by microwave heating was proposed, based on statistical theory (SLT) and support vector machine (SVM) theory, which relates the stability of PSZ and the influence factors, such as the holding temperature, rising rate of temperature, holding time, decreasing rate of temperature and hardening temperature. Typical data collected from 58 experiments were used for the training samples and test samples. Then testing and analyzing was done. The results showed that the SVM model is reasonable and it is accurate and reliable to predict the stability of the partially stabilized zirconia prepared by microwave heating by SVM model. Besides, multiple influence factors can be comprehensively considered in the SVM model, thus a new highly effective method for predicting the stability of PSZ prepared by microwave heating is provided for future application, which is of great significance to theory and practice.

The stability is one most important product performance index, which can directly determine the quality of the partially stabilized zirconia (PSZ), and the stability of PSZ is always fluctuating in the commercial process, so how to accurately, quickly and easily predict the stability of PSZ in the preparation process is very important. In the present paper, a new mathematical model to predict the stability of PSZ was proposed, based on statistical theory (SLT) and support vector machine (SVM) theory, which relates the stability of PSZ and the influence factors, such as the holding temperature, rising rate of temperature, holding time, decreasing rate of temperature and hardening temperature. Typical data collected from commercial process were collected for the training samples and test samples. Then testing and analyzing was done. The results showed that the max relative error was 1.80%, the least relative error was 0%, and the average relative error was 0.58%. It is accurate and reliable to predict the stability of PSZ by SVM model. Besides, multiple influence factors can be comprehensively considered in the SVM model, thus a new highly effective method for predicting the stability of PSZ is provided for commercial application.

The TG and DTG curves of self-made ZnO precursor were studied by the thermo-gravimetric analysis method in N2 atmosphere from 25°C to 650°C at the heating rate of 5, 10 and 15°C/min. The TG curve showed that the decomposition process started at about 150°C and finished at 300°C, in accordance with the temperature range of the decomposition from basic zinc carbonate to zinc oxide. The first level chemical reaction based on Coats-Redfern method was applied to estimate the activation energy of the decomposition. The correlation factor was about 0.99, and the calculated average activation energy was 33.89kJ/mol. Active zinc oxides were perpetrated by microwave heating at 350°C for 30min. Their composition and surface morphology were investigated by using scanning electron microscope and X-ray diffraction and its quality can reach the first-grade standard of HG/T2572-94.

In recent years, amounts of permutation-diffusion architecture-based image cryptosystems have been proposed. However, the key stream elements in the diffusion procedure are merely depending on the secret key that is usually fixed during the whole encryption process. Cryptosystems of this type suffer from unsatisfactory encryption speed and are considered insecure upon known/chosen plaintext attacks. In this paper, an efficient diffusion scheme is proposed. This scheme consists of two diffusion procedures, with a supplementary diffusion procedure padded after the normal diffusion. In the supplementary diffusion module, the control parameter of the selected chaotic map is altered by the resultant image produced after the normal diffusion operation. As a result, a slight difference in the plain image can be transferred to the chaotic iteration and bring about distinct key streams, and hence totally different cipher images will be produced. Therefore, the scheme can remarkably accelerate the diffusion effect of the cryptosystem and will effectively resist known/chosen plaintext attacks. Theoretical analyses and experimental results prove the high security performance and satisfactory operation efficiency of the proposed scheme.