Search

Graded sintering is the fundamental process of fabricating functionally gradient cemented carbide (FGCC). The diffusion-induced mass transport in cemented carbide can result in the formation of gradient microstructure and thusly lead to gradual changes in micro property. So far, several types of FGCC have been developed, and the factors that can influence the gradient formation are complex. Section 2 introduces the process of forming diffusion-controlled near-surface layer in WC-Ti (C,N)-Co hardmetal as well as the kinetic modeling work that reveals the key factors for the layer formation. Section 3 reviews the dual properties carbide produced under carburization atmosphere, for which the carbon content is a main factor of the gradient thickness. There are two models describing this process, representing different mass-transport mechanism of the so-called liquid phase migration (LPM) process. In section 4, previous and new results of modeling LPM in different dimensions and scales are presented, and the diffusion-controlled nature of LPM are discussed.

A variety of micro forming processes has been invented, and the size effects have become a research hotspot at home and abroad. Micro bending molds with different feature sizes were designed. Quasi-static tester loading and dynamic laser shock loading with soft punch for micro bending forming was studied by numerical simulation respectively based on ANSYS implicit analysis and LS-DYNA explicit analysis. The constitutive models of workpiece are bilinear kinematic hardening model and Johnson-cook model respectively. The effects of different loading conditions and feature sizes of the die on the forming depth, equivalent plastic strain and equivalent plastic strain rate were studied. The results of numerical simulation show that, with the increasing of feature size of the mold, the forming depth under two kinds of loading conditions shows a tendency to increase. In dynamic laser shock loading, the equivalent plastic strain and equivalent plastic strain rate of the key position of the bent part would decrease with the increasing of the feature size of the die. While in quasi-static loading, the opposite law is shown. The research shows that, the flexible micro-bending processes with different loading models showed similar size effect. However, compared with quasi-static loading, in dynamic loading, the strain of forming parts is more centralized, and there is a high strain rate and better formability of the workpiece.

Based on the laser-driven flyer micro forming and laser high-speed impact welding, this paper put forward the laser high-speed impact synchronous welding and forming new process, and builds the compound welding experiment platform. The three-dimensional deep field digital microscope of KEYENCE VHX-1000C was used to measure the surface morphology and the maximum deformation depth of the welding and formingsamples. By observing the surface morphology of the sample, it was found that strong plastic deformation occurred on the surface of the materials and well reproduced the shape of the mold. When the laser energy was below 4.5J, the maximum deformation depth of the samples increased with the laser energy. However, the maximum deformation depth decreased due to the spring back phenomenon when the laser energy was larger than 4.5J. The Axio CSM 700 confocal microscope was used to measure the morphology of the welding interface. The cross profile of the welding interface showed that most regions had been welded and the welding interface was nearly flat.

Calcium aluminate cement (CAC) is a penitential candidate for bone replacements with good bioactivity but relative lower strength. In this study, biodegradable PGA fiber was incorporated into the CAC paste in order to improve the strength of the material. And MC3T3 cells were seeded on the surface of CAC and CAC/fiber to study their in vitro biocompatibility. The results indicate that the PGA fiber can improve the compressive strength of CAC without changing the crystalline phases and micromorphology. Calcium aluminate oxide hydrate, katoite and Gibbsite crystals were detected by XRD. Plate-like crystals can be observed under FESEM. The MC3T3 cells were attached well on both CAC and CAC/fiber composite, indicating their good in vitro biocompatibility. In summary, fiber reinforcement can be an effective way to improve the properties of calcium aluminate cement for orthopaedic application.

Polypropylene (PP) membranes were respectively prepared using adipic acid (APA) and Sorbitol (NA-40) as nucleating agent via thermally induced phase separation (TIPS) method. The effects of nucleating agent content and cooling temperature on the structure and performance of membrane were investigated using scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). WAXD spectrogram indicates that three kinds of α, β and γ-form crystal were formed in this preparation process and the relative content of β-form crystal in membrane prepared by NA-40 system is higher than that of membrane formed by adipic acid. SEM images show that porous structure and cellular structure were observed on the surface and cross-section of membrane. The water flux, tensile strength and elongation increase with the addition of nucleating agent content and decrease with cooling temperature rising. This paper aims to choose proper nucleating agent NA-40 and coagulation temperature to improve the properties of PP membranes.

Joining between polyamides (PA) and metals has potential applications in the industry. Based on PA66GF and AISI304, the experimental study of laser transmission joining of the dissimilar materials is conducted in this article. Firstly, comprehensive experiments of laser transmission joining between PA66GF and AISI304 are carried out by Nd: YAG pulsed laser source according to the central composite rotatable design method (CCRD). Secondly, the effects of the process parameters like voltage, joining speed and stand-off distance on the joint quality are analyzed by response surface methodology (RSM). Finally, mathematical models between the process parameters and the lap-shear strength and the joint width are established and based on which, the optimization of the joining process is done and the optimized results are predicted. The results show that the process parameters of laser transmission joining play a significant role in determining the joint quality; the predicted data of the models are in good agreement with the experimental results and can be of great help for the optimization of the joining process. As a result, this study could provide an effective instruction about how to choose the reasonable process parameters for enhancing the joining efficiency.

Light scattering of the upper polymer have a great influence on welding quality. Light scattering of high density polyethylene (HDPE) and low density polyethylene (LDPE) are assessed by constructing experiment and numerical computation method. Firstly, the beam quality of semiconductor laser is analyzed, power flux distribution of the laser beam in a defocused plane is measured by knife edge method; Afterwards, the power flux distributions of the laser beam after passing through HDPE/LDPE are measured by line scanning method; Lastly, with the combination of the mathematical model which is used to calculate scattering coefficient and standard deviation of scattering, scattering related parameters and the laser power flux distribution at the welding interface are obtained by writing a program in MATLAB. The results show that the light scattering coefficient of high density polyethylene is up to 0.988, the light scattering coefficient of low density polyethylene is 0.92; Higher crystalline polyethylene leads to more obvious light scattering; the laser beam power flux distribution at the weld interface affected by scattering is determined, which lays a solid foundation on numerical simulation in laser transmission welding.

The pyrolysis kinetics parameters of material had an great importance on estimating material degradation during laser transmission welding. The PA66/CB was produced using a twin-screw extruder, and thermogravimetric experiment of PA66/CB was performed at different heating rate of 5, 10, 15 and 20 °C/min, then the pyrolsis behavior and pyrolysis kinetics parameters of material were investigated based on the Kissinger, Starink and Freeman-Carroll three methods. The results showed that the pyrolsis process of PA66/CB was one step reaction. With the increase of heating rate, the initial reaction temperature and final pyrolsis temperature of TG curve and the peak temperature of DTG curve were shift to higher temperature. Temperature hysteresis was appeared but the final pyrolsis rate was not affected by heating rate. The activation energy on the biggest pyrolsis rate was not affected by the addition of carbon black. The activation energy calculated using Starink method was increased by the increase of conversion rate. The activation energy calculated using Freeman-Carroll method was bigger than Kissinger and Starink methods. The activation energy was calculated using Freeman-Carroll method, then using the nthmodel, and the pyrolsis kinetic equation was expressed as:dα/dt=2.053×1019[exp (-245.32×103/RT)](1-α)2.22.

Because of its advantages of high strength, good toughness and strong corrosion resistance capability, SMA490BW was access to a wide range of applications in bogie frame of high-speed train. Manual welding, single-wire automatic welding and double-wires automatic welding were used to weld plate butt joints of SMA490BW steel. The mechanical properties testing and microstructure observation were carried out. Results showed that the strength of welded joint and impact toughness could meet the design requirements with the above methods. Double-wires welding owned an outstanding advantages of saving energy and welding productivity in such the above methods which laid the foundation for application of double wires welding in bogie frame of high-speed train.

The double membrane bio-reactor was used to treat the simulated wastewater under aerobic conditions, and the aerobic activated sludge system was set as the control. At the beginning of acclimation, COD removal efficiency in double membrane bio-reactor was higher than that of aerobic activated sludge system, but difference between two systems was little in later stage. The ammonia nitrogen removal rate in double membrane bio-reactor was significantly higher than aerobic activated sludge throughout the whole acclimation stage and nitrite concentration in the effluent from double membrane bio-reactor was lower than that of from aerobic activated sludge, while the nitrate concentration was higher. The nitrite was not accumulated in double membrane bio-reactor through the whole process of acclimation, while the accumulation of nitrate happened in aerobic activated sludge system.

Carbon nanodots (CDs) have been synthesized by chemical oxidation of C6H12O6 in NaOH solution . The as-prepared CDs possess strong blue luminescence.KH560 serve as coupling agent to modify the quantum dots by the method of ultrasound reaction .Finally the obtained C-dots powder have been successfully grafted with quercetin,which is one kind of flavone .This process made the drug have better thermal stability.

5-(4-nitrophenyl)-2-aminopyrazine (13) was synthesized from 2-aminopyrazine (9) through two steps including monobrominated reaction, Suzuki-Miyaura coupling and the structures were confirmed by 1H NMR and MS spectrum. The synthetic method of 13 was optimized and can be used to synthesize 5-(4-nitrophenyl)-2-aminopyrazine derivatives.

In order to increase antifouling ability of PVDF membrane, crosslinking PEG as antifouling medium in membrane bulk was studied. PEG with different moleculer weight were crosslinked in membrane solution with TMC as crosslinking agent, ATR demonstrated crosslinked PEG were retained in membrane bulk and surface wetting property was improved with contact angle characterization. According to the dynamic fouling test of BSA solution, the PVDF-T1000 membrane exhibited the best antifouling ability with the FRR value as high as 90%.

4-Oxo-4H-chromene-3-carboxylic acid (8) is an important intermediate in many biologically active compounds. In this work, a rapid synthetic method for compound 8 was established. The compound 8 was synthesized from the commercially available 1-(2-hydroxyphenyl) ethanone 9 through two steps including vilsmeier reaction and oxidation by Jones reagent. The structure was confirmed by1HNMR and13CNMR spectrum. Furthermore, the synthetic method was optimized.

The theoretical analysis of frost formation had been made. The wind speed, temperature and relative humidity etc. had different effects respectively. A single heating was studied through the experiment. In different outdoor conditions, experimental data showed evaporator frost at the environment temperature of 10 °C, environment relative humidity was 70%. Comparing the experimental data, it is concluded that temperature of evaporator’s outlet is increasing with the outlet temperature. The refrigerant evaporation temperature and COP under different conditions has been tested. The relation of evaporation pressure and environmental temperature under different evaporation temperature had been concluded. According to the experiment, a defrost measure of this experiment equipment had been proposed.

Deformation of helical buckling appears on tubing string under axial compressive loads, and it may even make the tubing string fail when the loads are excessively large. To make clear stress distribution and variation of helical buckling tubing string, the formulas of equivalent stresses inside and outside of the tubing string are deduced based on the spring theory and the fourth strength theory. From the analysis, we can see that the equivalent VonMises stress increase with the clearance of tubing string and casing, and the increase are 22.44 percent and 45.9 percent respectively for inside and outside stress with clearance increase form 29.1mm to 39.69mm. The proposed method used for the helical buckling tubing string makes up the insufficient of traditional tubular mechanics effectively.

The composition of dyeing wastewater is complicated, after biochemical treatment, the effluent COD is still unable to meet the emission standard. To achieve discharge standard that often require advanced treatment after biochemical. This paper investigated effect of pH, reaction time, ZnO dosage, dosage of H2O2on the effect of dyeing wastewater treatment by photocatalytic-H2O2, the results showed that the reaction time of 15 min, pH of 4, dosage of ZnO was 4 g/L, 30% H2O2dosage was 1 ml/L, the COD removal rate was highest, can reach more than 55%.

Matrix factorization is a collaborative filtering recommendation technique proposed in recent years.In the process of recommendation,each prediction depends on the collaboration of the whole known rating set and the feature matrices need huge storage. So the recommendation with only one node will meet the bottleneck of time and resource. A MapReduce-based matrix factorization recommendation algorithm was proposed to solve this problem.The big feature matrices were shared by Hadoop distributed cache and MapFile techniques.The MapReduce algorithm could also handle multi-λsituation.The experiment on Netflix data set shows that the MapReduce-based algorithm has high speedup and improves the efficiency of collaborative filtering.

The value of peak gas production and the time when it reaches are two important marks for coal bed methane (CBM) well’s gas production curve. This paper takes M CBM gas field of A country’s B basin as actual production instance. Firstly, based on the CBM producing mechanism, the existence reason of peak gas rate is analyzed; secondly, the influencing factors of the value of peak gas production and the time when it reaches is studied by numerical simulation method. And sensitivity order of the influencing factors is obtained. The study results indicate that: the value of peak gas production has positive correlation with properties: permeability, gas content, coal bed net pay and gas saturation; while negative correlation with desorption time and cleat porosity. And the strong to weak intensity of sensitivity is permeability, gas content, desorption time, net coal bed pay, cleat porosity, gas saturation. The time when peak gas production reaches is markedly influenced by the value desorption time and cleat porosity, the smaller of the two parameters, the shorter of the time when peak gas production reaches.

Seismic inversion methods include constrained sparse pulse inversion and band limit inversion, etc. Although resolution of the seismic inversion results is higher than seismic data, it does not identify thin interbedding sand body and confirm the development of reservoirs. In this paper, in A block of Indonesia adopted geostatistical inversion in reservoir prediction, which is a method of seismic inversion combining geological statistics simulation and seismic inversion. This inversion method can establish various 3D geological model with the same probability of rock properties and lithology and it obey all seismic, logging and geological data. Using statistical regularity and seismic inversion technique we can obtain more fine reservoir model and finally reach the purpose of identification of single thin sand layer.

The typical characteristic of stoning band coal seams is of multi-layers and low permeability, so fractured vertical well is usually used in the CBM development of this kind of coal seams. As far as the reservoir simulation of vertical fractured CBM wells is concerned, the fracture characterization technique is of great importance. Taking the vertical fractured pilots in F coal measures of Bowen Basin in Australia as an example, this paper will illustrate the application of fracture characterization technique in reservoir simulation. Its highlight is to scientifically characterize the shape of hydraulic fractures and quantitatively describe the reservoir permeability improvement after fracturing through “MULTX” of grid conductivity with Tartan grid model, thereby determining key parameters for the reservoir simulation of fractured vertical wells and providing a scientific basis for establishing CBM development plan and forecasting ultimate recoverable reserves.

Because the extremely low permeability for tight gas reservoirs, lead to the way to seepage and the shape of production curves different with the convention reservoirs; this will increase the difficulty to develop the tight gas reservoirs; on the other hand, the convention exploit cannot recover the tight gas with commercial value, with this problem, the main solution is the technology of multi-stage fractured horizontal wells, the fractured can provide the channel for gas to transport, the horizontal wells can increase the seepage area of tight gas, it’s the guarantee to get the commercial value. But, at present, the study on the tight was dependent on the method of convention gas reservoirs, the production curve get from this method also the same with the convention gas reservoirs, in order to close with the really exploitation of tight gas reservoirs and provide the more accurate scientific evidence, we must study based on the feature of tight gas reservoir, in this situation, we can get the suitable production curves for tight gas reservoirs. This paper based on the feature of tight gas reservoir, combine with the model of multi-stage fractured horizontal wells, and get the production equation of tight gas, combine with the yield of discard time, we can get the type curve, and then get the C level reserves of region.

The complexity of geological conditions results in ambiguity and uncertainty when interpreting geological data, bring difficulties to geological modeling, so quantitative evaluation of uncertainty of various geological parameters is important to establish accurate geological modeling. M coalbed methane field in eastern Australia was selected as an example to explain this process. The parameters and these uncertainty ranges were discussed firstly. And then, the impacts on calculated reserves of parameter uncertainty were analyzed. A better effect was attained in M coalbed methane field with this method.

The paper addressed the issues of limited resource for data optimization for efficiency, reliability, scalability and security of data in distributed, cluster systems with huge datasets. The study’s experimental results predicted that the MapReduce tool developed improved data optimization. The system exhibits undesired speedup with smaller datasets, but reasonable speedup is achieved with a larger enough datasets that complements the number of computing nodes reducing the execution time by 30% as compared to normal data mining and processing. The MapReduce tool is able to handle data growth trendily, especially with larger number of computing nodes. Scaleup gracefully grows as data and number of computing nodes increases. Security of data is guaranteed at all computing nodes since data is replicated at various nodes on the cluster system hence reliable. Our implementation of the MapReduce runs on distributed cluster computing environment of a national education web portal and is highly scalable.

SIS well is a successful technology for coalbed methane development. In this paper, the drilling and completion technology were introduced systematically on the aspects of optimization design of well profile, drilling equipment, drilling and completion technology of vertical well and horizontal well, and intersection technique of these two wells. Two new well patterns, i.e., commingled well and boat-shape well were also proposed. When application this technology to other areas, some improvement may should be made according to special geological data.

Due to life threatening situations, timely sending of data is essential. In this study transmission delay of different paths, through which data is sent from sensor to health care center over heterogeneous multi-hop wireless channel is analyzed. Data of medical related diseases is sent through three different paths. In all three paths, data from sensors first reaches ZigBee, which is the common link in all three paths. Wireless Local Area Network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX), Universal Mobile Telecommunication System (UMTS) are connected with ZigBee. Each network (WLAN, WiMAX, UMTS) is setup according to environmental conditions, suitability of device and availability of structure for that device. Delay of data reaching each device is calculated and represented graphically. Main aim of this study is to calculate delay of each link in each path over multi-hop wireless channel.

Coal bed methane (CBM) is a kind of natural gas that generated from coal and disseminated organic matters during the stage of diagenesis and coalification, which mainly composed of methane and hosted in coal seam by free, adsorbed, and dissolved forms. Genetic, reservoir type and occurrence condition in CBM are different from traditional reservoir. And the high-produced development wells in CBM aiming to drill more coal seams with high quality therefore needs to be analyzed in the methods that are different from traditional reservoir. 3 important factors including the study on correlation and elevation depth of coal seam roof and floor in section and areal by using well-seismic ties, outcrop boundary based on coal mine data and distributions of CBM reservoir properties in 3D model are needed for high-produced development well analyze in CBM. Application in Australia CBM project shows this methodology is very successful for the development well design with high production.

Based on the analysis of coring, logging and experimental data, fine evaluation on Fort Copper Coal Measures (FCCM) of Early Permian Blackwater Group in north Bowen Basin of Australia has been done. FCCM is a potential coal measure. Eight coal seams exist in FCCM. Laterally, they develop steadily. Seams of FCCM characterize interbedding with partings, high ash content, high gas content and mediate-low permeability. The content of partings, which are groups of siltstone, mudstone and tuff, ranges from 15% to 55%. The cumulative thickness of pure coal ranges from 40 to 60 m. The ash content ranges from 20% to 70%, averaging 45%. Coal seams gas content is as high as 7% to 15%, benefitting from the dense rock block effect on the top and bottom, as well as the interplayers. The permeability ranges from 0.1 to 10 mD laterally. Parameters above show FCCM has good developing potential. Western slope of Nebo syncline is suggested as the favorable area, considering its good developing factors such as shallow buried depth of coal seams, relatively high permeability and effective gas preserve environment. Meanwhile, gas in partings can be considered in collaborative development strategy. Developing gas along with ash will be the focus of future development evaluation.

Two novel thiopyrano [4,3-d] pyrimidine derivatives 7 and 8 were synthesized from dimethyl 3,3'-thiodipropanoate through six steps including two times of cyclization, chlorination, oxidation, substitution with morpholine and piperazine and their structures were confirmed by1H NMR and MS spectrum. The total yield of the six steps was 18.6% (calculated from methyl dimethyl 3,3'-thiodipropanoate). The synthetic routes of them can be used to synthesize PI3K/mTOR inhibitors bearing a thiopyrano [4,3-d] pyrimidine nucleus.

Study on the pretreatment of printing and dyeing wastewater with PAC、Fe2(SO4)3and FeCl3was carried out. Effects of the flocculants dosage, pH on the treatment efficiency were studied. The results showed that with PAC, Fe2(SO4)3and the FeCl3dosage rising, the treatment effect first decreased and then increased and when the addition amount was 300 mg.L-1、300mg.L-1and 250 mg.L-1,the COD removal efficiency achieved 69%、78%、74% , respectively. With the rising of pH, the treatment effects of the three types of flocculants increased first and then decreased, the optimum pH of PAC and Fe2(SO4)3was 7and the best pH of FeCl3was 6. At last, the settle ability and the amount of the producing floc were studied, the results showed that the settle ability was the best and the least amount of sludge produced by FeCl3flocculation. Keywords: printing and dyeing wastewater, pretreatment, flocculants, screening.

Laser transmission welding (LTW) is a new and efficient technology. During LTW of polymers, the size and morphology of the weld have great influence on the welding quality. In order to better evaluate the welding quality and optimize process parameters, many researches on the morphology and mathematical analytical model of the molten pool have been conducted. This study attempts to build an analytical model for calculating the depth of the molten pool (molten depth), based on the temperature field distribution theory of the moving point heat source acting on the semi-infinite body. The influence of the welding power and welding speed on the molten depth is studied emphatically. The mathematical analytical model is solved through MATLAB mathematical software. Subsequently, the test experiment about LTW of PA66 is conducted to validate the model. During the test experiment, the upper layer contains 30 wt. % glass fibers (GF) and the bottom layer contains 30 wt. % carbon fiber (CF). The result shows that the mathematical analytical model can well predict the trend of the molten depth. However, the error exists indeed. The detailed analysis about the error is also made in this article.

Standard particle swarm algorithm for function optimization prone to local optimal and premature convergence, and thus the biological chemotaxis principle introduction to particle swarm optimization algorithm, this paper proposed an improved algorithm to maintain the diversity of the populationand the choice of key parameters. Simulation results show that, compared with the traditional particle swarm optimization algorithm, an improved particle swarm algorithm for dealing with complex multimodal function optimization problem can be significantly improved algorithm for global optimization.

Laser shock micro-adjustment is a precise and noncontact adjustment technique using laser-shock-waves to adjust the curvature of micro-components. The experimental studies have indicated that: when laser shock region is located at the free end of cantilevers, multiple impacts are applied to achieve a large bending degree; meanwhile, different bending directions can be obtained with multiple impacts in the junction position. Efforts should been made to understand the mechanisms of multiple laser shock micro-adjustment. Two mechanisms have been proposed for describing the laser shock micro-adjustment in different laser shock regions, namely shock inertia mechanism and material flow mechanism. The proposed micro-adjustment mechanisms can predict bending angles and directions. To validate the proposed micro-adjustment mechanisms, numerical simulations were carried out based on the FEM method using the ANSYS/LS-DYNA software and the corresponding results demonstrate the proposed mechanisms.

A laser direct joining (LDJ) experiment of titanium alloy (Ti-6Al-4V) and carbon fiber reinforced nylon (PA66CF20) is presented here using diode laser equipment. Experimental design and experiment of LDJ are carried out according to a single process parameters range obtained from the previous experiment. Response surface methodology (RSM) in Design-Expert v7 software is adopted to establish the mathematical model between LDJ process parameters and joint quality. Then the interaction effects of joining process parameters (laser power, scan speed and stand-off distance) on joint quality are investigated using analysis-of-variance (ANOVA), and the result shows that the interaction effect of laser power and scan speed on joint quality is the greatest. Finally, the predicted values from the mathematical model established by RSM are compared with the experimental values, and the process parameters are optimized to obtain the strongest joint strength. The result suggests that the predicted values are in good agreement with the experimental ones. The purpose of predicting and optimizing joint quality based on reasonable process parameters is achieved.

Laser impact welding (LIW) is a novel welding technique which uses laser induced shock waves to obtain the solid-state and metallurgical bonding between flyer and base plates, and can be applied in welding of dissimilar metal plates in micron level. In this paper, experimental study is conducted with titanium as the flyer plate and aluminum as the base plate under different laser energies and laser spot diameters. Besides, the microstructure and mechanical properties of the welding joints are also investigated. The wavy interface is observed by metallographic investigation which is similar to explosive welding and electromagnetic pulse welding. Moreover, the micro-hardness taken from the interface region shows an obvious improvement compared with the base metal. It is also found that laser shock welding results in fine grained structure of titanium on the weld interface. In conclusion, laser shock welding can not only improve the material microstructure of weld interface, but also avoid the heat affected zone and formation of intermetallic phase during dissimilar metal welding. Therefore, it is a promising welding technology in the field of MEMS.

White body in the design process needs to meet the needs of a wide range of performance requirement. Adequate stiffness and modal are the basis to ensure the vehicle’s performance of vibration noise. Simultaneously, in order to reduce energy consumption and cost, the lightweight design of the white body has become the mainstream. In this paper, the optimization design is conducted for stiffness and modal of a commercial vehicle’s white body based on the theory of the finite element size sensitivity optimization design. Firstly, build the finite element model of a vehicle’s white body and analyze its stiffness and modal. Some changes were made to the car-body’s partial structure according to the distributing of strain energy achieved from above analysis, which improved the car-body’s dynamic and static performance initially. Secondly, choose panels needed to be optimized by reference to the density of strain energy and panels’ mass. Then, the car-body’s structure was optimized using panels’ thickness as design variables, stiffness and modal frequencies as constrains and minimizing weight of white car-body as objective. After the analysis of the result, modal separation was put forward to improve the quality of this finite element optimization design model. Finally, the car-body’s stiffness and mode nature entirely satisfied the requirements with car-body’s weight decreased.

This paper presents an experimental study to evaluate the feasibility, characteristics and mechanism of laser direct joining between metal and carbon fiber reinforced plastic (PA66CF20). This study presents a method to improve the joint strength of the metal-polymer hybrid joint. The investigation study effects of process parameters (laser power and travelling speed) on the quality of joining joint. Macroscopic morphology of joint and PA66CF20 melting region closed to the interface were observed in this study. XPS analysis shows that Ti-C and Ti-O chemical bonding were produced between titanium alloy and plastic. Cross-sectional photo showed the melted polymer flowed into micro-cavity of metal surface caused by roughness of metal and thus formed mechanical bonding. Finally, the titanium alloy surface was structured in four different surface textures using a pulsed laser. Then the metal was joined with the plastic. The result shows that the joint strength of metal after laser-structured joining with plastic had been improved greatly.

The influence of H2O2、addition of Fe2+、pH、reaction time and temperature to advanced treatment effect of printing and dyeing wastewater with Fenton oxidation was studied. The results showed that when the addition of H2O2(the concentration was 30%) was 3mL/L,the addition of FeSO4·7H2O was 1.6g/L,pH was 4,the temperature was about 30°C,reacting time was 35min,the COD removal efficiency achieved above 55%,COD of effluent was below 45mg/L.

In this paper, the preparation of PANI was investigated via in secondary doping in-situ chemical oxidation polymerization. We use NH2SO3H as dopant, and HP3O4, H2SO4or HCl as secondary dopant, respectively. The influencing of products conductivity was discussed about difference secondary dopant with changing concentration. The synthesized polymer composites are characterized by Fourier Transform Infrared Spectroscopy (FTIR) and four probe conductivity apparatus. The results show that in redoping process, the conductivity of PANI was 3.1746 S/cm when the concentration of HCl was 1.0 mol/L. Meanwhile, the thermal stability of PANI prepared with HP3O4or H2SO4as secondary dopant was better than HCl as secondary dopant.

With the demand of high-quality and aesthetical products in the domain of medical microbiology, it’s more and more important to join micro weld. Due to traditional joining methods’ difficulty in meeting the demands, laser transmission micro-joining is of great significance. The materials used to laser transmission micro-joining based on the mask are PET, and the experiments are conducted on diode laser. The weld geometry with different gap widths on the mask is demonstrated at the same process parameters. In addition, the causes of forming different morphologies are analyzed. The formation mechanism of weld is analyzed as well. Moreover, process parameters’ effects on joint strength and joint width are deeply explored when gap width on the mask is 0.3mm. The results show that100 um micro weld joint is realized. At the same time, the range of process parameters is determined.

This article uses semiconductor laser for mask assisted laser transmission micro joining PET and PET with clear weld absorbents, the mask slit width is 0.3mm, using CCD to plan experimental design. The mathematical model of joining process parameters with joint strength and joint width was established using response surface methodology. Experimental verification was also done. The actual joint width was compared to mask slit width and the process parameters were optimized. The results show that the mathematical model can response the relationship between process parameters and joining quality, the mask can effectively control the joint width, reasonable process parameters can obtain high-precision, high-intensity joining quality.

Laser-driven flyer micro forming process is a promising microforming technology with the advantage of high efficiency, low cost, high flexibility. A series of experiments are conducted to investigate forming ability of aluminum foil with the thickness of 50μm. The effect of forming temperature and laser energy on forming ability characterized by forming depth, forming accuracy and surface quality is quantitatively analyzed. It is found that forming depth observed through three dimensional topography increases with the enhancement of forming temperature and laser energy. By elevating the forming temperature, the preheated workpiece suffers more homogenous deformation, presenting better forming accuracy. However, a certain degree of deterioration of surface integrity at the forming temperature of 200°C can be attributed to the earlier appearance of micro cracks caused by excessive thinning even at low laser energy. Overall, it is concluded that the optimal forming temperature is appropriately 150°C as the forming depth and forming accuracy is improved with no deterioration of the surface integrity.

Its switch frequency can’?t be high because of the restrains of insulated gate bipolar transistors (IGBTS) when high power electrical motor driven by matrix converter. This paper mainly discuses about the reason for output voltage error with low switch frequency. And based on the reasons, a method for decreasing output voltage error is proposed, that is to say that referenced input current and output voltage is calculated by using their average value in one sample in the indirect space vector pulse modulation (ISVPWM) when switch frequency is low. Simulation results coincide with theoretical analysis, verifying that the proposed method is feasible and theoretical analysis is right.

Wax precipitation of oil production wells seriously influence the oil production. In order to improve the level of wax removal, it is necessary to predict the depth, thickness and period of wax precipitation in the wellbore with oil production. On the basis of the mechanism analysis for wax precipitation in the wellbore, the theoretical model and empirical model were built up and programmed wax precipitation of oil production wells software and the results by the two models were compared. The sensitive factors which influence wax precipitation in the wellbore were analyzed. The results show that the two models can be used to predict the wax thickness, depth and precipitation cycle. The empirical model for wax precipitation profile prediction is more accurate than the theoretical model. The wax precipitation varies with the productive time and water cut.

The probability of S-N curve is one of the basic material fatigue reliability analysis and design. Determination of S-N curve is the basis of the fatigue life of obedience lognormal based on the application of statistical methods to fit the experimental data obtained fatigue. This paper studies the construction of reinforced Fatigue S-N Curves overloading effect on the structural performance of the bridge. In this paper, the fatigue reliability theory as a useful supplement, has some theoretical significance and value of work.

In this paper a new horizon-based shipborne camera video stabilization algorithm is implemented. First, the edges are obtained by Canny operator, then effective lines are obtained by Hough transform. In order to get the horizon within the existing lines, a fast filter-based method detecting the lines location differences is proposed, and image stabilization is implemented by the difference with the current horizon and base horizon. Experiments show that the algorithm can meet the real-time requirements, and can achieve the better image stabilization effect even in the conditions of bad light and fogs.

Mineral polymer is a new category of inorganic non-mental materials, which was manufactured from metakaolin in this paper. Changes of metakaolin in the polymerization could be described as: (1) the glassy parts of the metakaolin were dissolved in the high molar alkaline solution and some SiO, AlO bonds of them broke; (2) at the presence of OH-and Na+, these broken bonds formed aluminosilicate gel and then transformed into zeolitic precursors with changing compositions and concentrations of the solution; (3) by dehydration, these zeolitic precursors changed into the amorphous phase materials. NMR analysis indicated that in the geopolymeric products cured for 28 days, Q4(2Al) was the principal form of Si element and the content of four coordinate Al was increasing with the reaction. The experimental results provided a good basis for understanding the reactive mechanism of polymerization during processing of geopolymer products.

Three different panel density of sandwich composites were designed. The composite was reinforced by spacer fabric woven with polyester filaments, fiiled by polyurethane foam in the space of the fabric and composite the epoxy resin on the surface of the fabric. The effects of different panel density on the mechanical properties of sandwich composite were tested,including the shear property and peel property. The results showed that the panel density have some effects on the mechanical properties. Shear and peel property increased with the panel density increased.

Functionalized magnetic silica nanospheres were prepared by hydrolyzation of tetraethyl orthosilicate (TEOS) on Fe3O4and modification of Fe3O4/SiOx. Structure of functionalized magnetic silica nanospheres were characterized by transform infrared spectroscopy (FTIR) and differential thermal analysis (DTA). Cellulase was immobilized on functionalized magnetic silica nanospheres through cross-linking method. Saccharification rate of the immobilized cellulase is 70 % of that of free cellulase. The saccharification of the immobilized enzymes after 8 continuous uses still have 10 % of the initial saccharification rate, which demonstrate the potential of this immobilized cellulase for biofuel production.

This paper briefly introduced the main linear damages in the network layer of electric power Optical Transmission Network which contains fiber loss, chromatic dispersion and polarization mode dispersion. Based on the engineering practice in the application of power system, this paper studied the loss in the optical fiber cable line. The paper also studied chromatic dispersion and polarization mode dispersion. The calculation models were concluded and used for simulation verification. Each model can be used to power OTN engineering design.