Advanced Materials Research Vols. 179-180

Abstract: In this study a method to deposit a-Si:H-DLC film at room temperature has been explored by CVD. The interface structure of a-Si:H-DLC film and the compositions of DLC film were studied, the adhesion strength of DLC film deposited directly on metal substrates was very poor, there was an almost complete crack at interface between DLC film and metal substrates, the local shedding could also be observed on surface of DLC film. After inserting a-Si:H intermediate material into the interface, the adhesion strength of a-Si:H-DLC film was improved well, the a-Si:H intermediate layer with about 0.2μm thickness was formed, and was very impact. In addition the structures of DLC film mainly were graphite structure with SP2 bonding, and contain a certain amount of diamond structure with SP3 bonding. Load capacity of a-Si:H-DLC film deposited on the metal substrates was also evaluated, as the contact stress (Hertz stress) was less than 544MPa for the film with 1μm-thickness, the failure life was up to 100 million cycles or more by using “ball- on- disk” wear testing machine, therefore it could be used in practice. Changes in load had little effect on friction coefficient.

Abstract: Six strains named SY1 to SY6 were isolated from oil-polluted soil. The degradation tests of oil by our isolates were carried out under still-reaction-bottle-aeration and shaking-aeration conditions. The co-metabolic characteristics of two co-substrates (ethanol and glucose) and inorganic ions on the biodegradation of oil by our isolates were also studied. The results show that oil can be degraded by the six isolates effectively. The degradation ability of strains is enhanced due to co-substrates added. The enhanced roles of glucose are stronger than ethanol to SY1 and SY5; while the enhanced roles of ethanol are stronger than glucose to SY3.And the enhanced roles of glucose and ethanol are similar to SY2, SY4 and SY6. Inorganic ions, such as Ca2 + Fe2 +, Mg2+, etc, could promote the degradation ability of strains and improve the growth of strains. The degradation effects of mixed strains were inferior to that of single strain. After five days, the degradation rate of SY3 was worst, which was 65.7%. In the mixed strains, there were only 11 groups’ degradation rates greater than that of SY3, and other 46 groups’ degradation rates were less than that of SY3.

Abstract: The dynamic performance of the worktable has a great influence on machining quality. In order to improve the machining precision, the paper conducts the analysis and research on the workability of a numerical control engine bed rotary worktable from a domestic machine tool factory，and discusses the influence of dynamic characteristics of rotary worktable on the precision of numerical control processing. Firstly Ansys finite element analysis was employed to analyze and simulate the modality and natural frequency of the numerical control rotary worktable under various steps. And then, a vibration test on the numerical control rotary worktable to confirm accuracy of the simulation parameters was carried on. Finally a contrast was made between the theoretical analysis and the experimental analysis to point out the resonance frequency and the distortion of the rotary worktable. Also the influence of numerical control rotary worktable on the numerical control processing was discussed.

Abstract: In this article a new structure of a force sensor based on piezoelectric materials is proposed. The design and choice of measuring principle is based on the direct piezoelectric effect, for the measurement of the dynamic force, and on the analysis of the electromechanical impedance technique, for measuring the static force. This technique is based on the measurement of modes of the structure. Indeed, the application of stress on the structure will cause changes in the modes of the structure and appearance of new eigenmodes. Thus far these methods should allow for measurement of static force applied.

Abstract: The design of pre-forging is very important during multistage forging of producing gear blank. It directly affects the behavior of metal flowing, filled situation of die cavity of finish forging, quality of products and die life. Most designs of pre-forging for gear blank are based on trial and error method. This paper presents a suitable method for practical designation of pre-forging for gear blank by proposing an improved algorithm, which combines Back Propagation Neural Network and Genetic Algorithm. Firstly, the mathematical model between the size parameters of pre-forging and forming force and maximum die stress of finish forging was established by using Back Propagation Neural Network which has the feature of processing highly nonlinear problems. Secondly, the established model was set as the fitness function of Genetic Algorithm. At last, the most superior pre-forging shape and the size parameters were solved by using the Genetic Algorithm with the function of overall situation optimization. These can lead to lower cost and time in the stages of designing pre-forging for gear blank.

Abstract: Wheat straw is one of the most abundant and cheap lignocellulosic waste materials in the world. Nowadays, field burning is the major practice for removing wheat straw due to lack of effective utilization, but it increases the air pollution and consequently affects public health. Wheat straw is an attractive lignocellulosic raw material for binderless particleboard production. In this study, steam explosion was adopted as pretreatment method for wheat straw. The pretreated wheat straw was used to produce binderless particleboard panels. The influence of both pretreatment temperature and residence time on chemical composition of wheat straw, and modulus of rupture, internal bond and water absorption of panel boards was investigated. The results showed that defiberation of wheat straw raw material occurred during steam explosion pretreatment. The modulus of rupture and internal bond increased while water absorption of panels decreased as pretreatment severity increased. The optimum pretreatment condition, with 19.8 MPa of modulus of rupture, 0.2572 MPa internal bond and 61.5% of water absorption of panels, occurred under 170°C temperature and 10 minute residence time.

Abstract: The use of starch as a renewable and biodegradable adhesive is becoming increasingly attractive because of the environmental concerns about the industrial wastes generated from petroleum products and the growing awareness of the potential deleterious consequences of greenhouse gas emissions from these activities. Starch adhesive is most extensively used in corrugated board industry because of the abundant supply, low cost, renewability, biodegradability, and ease of chemical modifications. Starch adhesive has great effect on the performance, production technology and manufacturing cost of the corrugated board. It is of great importance to develop starch adhesive with stable properties, high performance, good viscosity, fast curing speed to meet the market requirement. In this paper, oxidation of starch by sodium hypochlorite under aqueous alkaline conditions with the aid of the catalysis of nickel sulphate at room temperature was investigated. The effects of sodium hypochlorite loading and caustic soda dosage on the properties of the starch adhesive were examined. Optimization of starch oxidation is desirable to achieve the highest initial tack and bonding strength. The optimum synthesis condition was obtained. Under the optimum condition, Under the optimum condition, 98.7% of the initial tack and 11.4 N/25 mm of the bonding strength were obtained respectively.. The modified starch adhesive showed great potential for industrial application.

Abstract: To overcome the disadvantages of getting into local optimum of the Ant Colony Optimization, this paper proposes a dynamic adaptive ant algorithm based on permutation. To avoid algorithms getting into stagnation in their anaphase, the lower bound of pheromones is set as a nonzero constant. According to the quality of the solutions ants get in the ant colony, the best part of the ants is selected to release pheromones in a defined amount in terms of the quality of the solutions so as to enhance ants’ capability of searching for optimum solutions in anaphase. The algorithm adopts a more intelligent selection rule of behavior , so the ants can adjust the balance coefficient between exploration and development dynamically in the searching process to effectively inhibit precocity phenomenon in the process of convergence，and improve the searching capability of the algorithm.

Abstract: Software architecture plays a more and more important role in measurement and control program design and development. It affects not only the progress of design and development, but also the gradual evolution potentiality of measurement and control system. This paper presents a COM/DCOM based N-layer software architecture and its usage in the design and development of the WFD2000 operating program. The application of this architecture greatly improves the reliability, configurability, flexibility and portability of the pressure measurement system.

Abstract: This paper puts forwards large audio blind watermark algorithm based on MDCT and compression principles of MP3.Using Hash function, psychoacoustic model and MP3 coding/decoding to realize real-time distilling, and validating watermarking recessive, capability, real-timing and etc through experiment and analysis. Experiments show that the scheme can obtain be a higher embedded capacity to change the original audio signal smaller, has good stealth, integrity watermark extraction time is short, and can be completed synchronously during the audio play process.