Search

There is a close relationship between cold ring rolling product quality and ring diameter growth rate in cold rolling process, but the technological parameters are main factors in influencing ring diameter growth. The paper used both numerical simulation and experimental verification to study the effect of the core roller speed and wide-diameter ratio on increment of ring diameter in cold rolling process of deep groove ball bearing inner ring. It is found that the core roller has greater influence on diameter growth, and the faster the feeding speed of core roller is , the greater the increment of ring diameter is. Finally, it is verified that the agreement between numerical simulation and experiments is good.

In the preparing process of carbon fiber, the fiber mechanical performance is affected by the pre-oxidation condition. In this paper the pre-oxidation technology condition of the original silk is researched, and the functional group in the molecule and the process of thermal gravimetric of the original silk and pre-oxidized silk are investigated by the method of infrared spectroscopy analysis and thermal gravimetric analysis. The IR analysis shows that associated hydroxyl is disappeared, Ar-H is decreased substantially, and methyl and methylene of the ring structure are changed greatly in the molecule of pre-oxidized silk. The TG analysis shows that the first weight loss temperature is increased, weight loss temperature range is moved to the higher temperature direction, the total weight loss rate is decreased, and weight loss velocity is decreased substantially. The mechanical performance of carbon fiber is affected by the pre-oxidation heating rate. When pre-oxidation heating rate is 1.5°C/min, the breaking strength of carbon fiber is 1195.84Mpa and the Young's modulus is 80Gpa.

A novel method was proposed for preparing oxychloride octahydrate by the two – step decomposition of zircon sand concentrate in sodium hydroxide system. The effect of decomposition temperature and NaOH – to – zircon mass ratio of each stage on the decomposition of zircon sand was investigated. The macrokinetics of the two – step decomposition process was also examined. The experimental date showed that the shrinking core model with diffusion through the residual layer is most applicable for the first step decomposition process with the apparent activation energy of 42.9 kJ/mol, but the second step process was controlled by chemical reaction with the apparent activation energy of 30.1 kJ/mol.

The dissolution kinetic of NaxH2-xTiO3(resulting from high titanium slag treatment by NaOH) by diluted sulfuric acid (38~51 wt. %) was carried out in temperature range of 10 to 50°C with an initial acid/NaxH2-xTiO3(wt.) ratio of 1:1. The effects of the sulfuric acid concentration and temperature on titanium dissolution percent were reported, and both of them significantly affected the dissolution rate. The experimental data indicate that the shrinking core model controlled by diffusion in product layer is most applicable for the titanium dissolution process, and the apparent activation energy has been estimated to be 28.69 kJ/mol.

In view of the current status of manual adjustment-dominated heating network adjustment, time-consuming information feedback and network balance, failure of network balance to achieve the best condition, and uneven heat and cold in a district, heat supply automation transformation technology program in this district is proposed to improve the efficiency of heating network and achieve the goal of energy conservation and emission reduction.

Webpage tamperproof technology is a website technology to protect webpage not to display tamper contents and to carry out real-time recovery. Webpage tamperproof system uses advanced Web server core embedded technology and tamper detection technology based on cryptography to give a comprehensive protection of static webpage and dynamic webpage of the website. Webpage tamperproof system supports the automatic release, tamper detection, application protection, warning, and real-time recovery of webpage, guarantees the safety of various links of transmission, identification, address access, form submission, and auditing, fully eliminates the possibility of access to tampered webpage in a real-time manner, and puts an end to any tamper of backstage database in a manner of Web.

Extraction of vanadium has been developed to extract vanadium from hydrochloric solutions with high concentration of iron ions. The effects of extraction conditions such as pH values, extraction time and extraction temperature on the distribution ratio of vanadium were investigated. The results showed that the distribution ratio of vanadium increased with the higher pH, the lower temperature and the longer equilibrium time. The distribution ratio reached 25 and the extraction ratio reached 96.2% by single stage extraction. When the organic phase was stripped with 2 mol/L hydrochloric acid at the phase ratio (O/A) 10:1, the vanadium stripping ratio of 98.3% could be achieved.

Hot stamping of the ultra high strength steel (UHSS) was studied to meet the requirements of lightweight of automobile. The coupled thermo-mechanical model for hot stamping was established with ABAQUS. Initial temperature of tools (die, punch, blank holder) and stamping speed were studied to insure the impact on the thickness, stress and strain of blank. It shows that punch fillet area is easy to crack. With the temperature of tools increasing, the sheet minimum thickness increases first and then decreases. With the increase of punch velocity, the sheet minimum thickness increases. Compared with the initial temperature of tools, punch velocity has a greater impact on the thickness. The simulation results are in agreement with the experimental results and provide a theoretical basis for the practical stamping process.

In this paper, experimental investigations on femtosecond laser (pulse duration:164 fs, wavelength:780 nm) micromachining of polycarbonate have been carried out in air. The lateral and vertical machining precision was evaluated by scanning electron microscopy and profilometer. The morphological changes were observed by scanning electron microscopy. The ablation mechanism varied with the laser pulse energy was discussed. The diameter and depth of the ablated crated are influenced by the laser pulse energy and the number of laser pulses. The relation between the diameter and ablation depth of the crater and the key parameters of femtosecond laser is obtained. Femtosecond laser micromachining of polycarbonate have a potential application of the fabrication of polycarbonate-based devices.

NaOH solution was utilized in the molten salt reaction of titanium slag for investigating desiliconization effects. The thermodynamic behaviors of Si in the reaction system was examined to explore the impacts of molten salt reaction conditions on the conversion rates of the foreign substance Si and the target element Ti. On this basis, the influences of NaOH concentration, liquid-solid ratio, cleaning temperature and cleaning time on Si removing rate were discussed. The experimental results showed that, Si reacted with NaOH to produce sodium silicate was feasible in terms of thermodynamics within the temperature interval 400-1000K. 3Na2O•2SiO2, 2Na2O•SiO2 could stably exist under high reaction temperature. As the reaction time extended and temperature rose, the conversion rate of Si was increasing. In the process of Si removing by NaOH cleaning of molten salt reaction products, as NaOH concentration, liquid-solid ratio, cleaning temperature and cleaning time increased, Si removing rate became larger. The optimum alkali cleaning conditions were: NaOH concentration 150g/l, liquid-solid ratio 3:1, cleaning temperature 50°C and cleaning time 60min, then the desiliconization rate reached 61.16%.

Experiment on ablation of silicon wafer on different crystallographic facet planes by single laser pulse irradiation was carried out with a femtosecond pulsed laser operating at a wavelength of 780 nm and a pulse width of 160 fs. The quality and morphology of the laser ablated silicon surface were evaluated by atomic force microscopy. The ablation threshold fluences on different crystallographic facet planes were obtained through the relationship between the squared diameter of the craters and pulse energy. The effects of different crystallographic facet planes of silicon wafer on the process of femtosecond laser ablation of silicon wafer were studied.

3D model of 6006 gulley ball bearing inner ring is established in this paper. Based on the study of finite element numerical simulation on the cold rolling process of inner ring by Deform-3D software, the paper shows the influence of the feed rate of idle roller, rotational rate of driving roller as well as wide-diameter ratio on the rules of rolling forming of bearing inner ring. Through the research of numerical simulation, it is discovered that feed rate of idle roller and wide diameter ratio have a greater impact on the ring end surface quality larger than rotational rate of driving roller does. Thus, process parameters should be chosen reasonably according to mold parameters and material parameters, which will help improve the stability of the cold rolling process and the rolling production efficiency.

This paper presents an optimization technology for the molecular design of environmentally friendly solvents for extractive distillation. The approach based on the concept of group contribution methods (GCM). To decrease the complexity and random of design problem, a set of functional groups are pre-selected based on the modified UNIFAC method. Combination of groups can produce different molecule, once the molecule is generated, the properties are evaluated to determine if it satisfy the criteria. The criteria include separation performance and environmental performance. Simulated annealing algorithm is used to search feasible molecular structures. The molecule transition strategies and parameters of algorithm are described detailedly. Finally, the method is demonstrated with two examples, and the design results show that the proposed technology is a valid technology to design the desirable solvents.

In order to reduce the silicon content to the maximum allowed value for the production of high-purity titanium dioxide, a hydrometallurgical process on the desiliconization during alkaline leaching of titanium slag under atmospheric pressure was studied. The effect of leaching temperature, initial NaOH concentration, leaching time and mass ratio of alkali to slag, on the efficiency of silicon removal were investigated. The results show that when the mass concentration of NaOH is 30%, mass ratio of alkali to slag 3:1, the leaching temperature 120°C and the retention time about 120min, the content of silicon in solid is reduced to 0.45%. Simultaneously, the content of aluminum is reduced to 1.62%, without affecting the content of titanium. The kinetics on the desiliconization during alkaline leaching of titanium slag was carried out. The results show that under the leaching parameters mentioned above, the apparent activation energy is calculated to be 45.43kJ/mol.

A novel process was proposed for the activation pretreatment of Cr-containing limonitic laterite ores by NaOH roasting. The dechromization kinetics of the laterite ores and the effect of particle size, NaOH-ore ratio, and roasting temperature on Cr extraction were studied in detail. Experimental results indicate that decreasing the particle size and increasing the NaOH-ore ratio and roasting temperature increase the Cr extraction rate. Approximately 96% Cr in the laterite ores could be extracted under the optimal alkali-roasting conditions. The results also indicate that the Avrami model is suitable for the dechromization process and that the apparent activation energy is calculated 11.12 kJ·mol-1. The 99.5% Cr2O3 was obtained from Na2CrO4 leached in the alkali solution by liquid-phase reduction and then calcining at high temperature.

The patent applications filings (PAF) are complex to conduct due to its nonlinearity of influenced factors. A novel way about nonlinear regression modeling of PAF with the potential support vector machines (P-SVM) is presented in this study. Grey theory is a truly multidisciplinary and generic theory that deals with systems that are characterized by poor information. However, the application combining grey system theory and P-SVM for PAF prediction is rare. In this study, a grey potential support vector machines with genetic algorithms (GPSVMG) is proposed to forecast PAF. In addition, Grey system is used to add a grey layer before neural input layer and white layer after P-SVM layer. Genetic algorithms (GAs) are used to determine free parameters of P-SVM. The experiments show that the GPSVMG model is outperformed not only single grey model but also SVM with genetic algorithms (SVMG) model and potential support vector machines with genetic algorithms (PSVMG) model. So, PAF prediction based on GPSVMG is of validity and feasibility.