2017 volumne 38卷 Issue 03
Lu Hongxia, Li Xue Xue, Leijun, Zhao Tiange, Shao Gang
Abstract: ZnSn(OH) 6 microl nanocubes with good dispersancy,uniform particle size distribution,and the average particle size for micro/nanoscale (100 ~200nm) were prepared by the hydrothermal method using (CH3COO)2Zn · 2H2O,NaOH and SnCl4 as reactants,and the acidificate the Zinc hydroxysta treatment,graphene oxide(GO) was prepared by a modified Hummers method.GO-ZnSn(OH)6 composite was prepared under the condition of low temperature,reduction graphene oxide (rGO) was obtained by photo induced reduction of GO under UV irradiation,and finally get rGO-ZnSn(OH)6 composite.The samples were characterized by the XRD,SEM,FT-IR,UV-Vis and PL to analyze the phase,microstructure and optical absorption properties,and the effect of different amounts of GO dopant on the photocatalytic property of rGO-ZnSn (OH) 6 composite was also evaluated using methylence blue as the degradation of material.The results showed that the mass fraction of GO was 2.0 (massfraction,%),the maximum degradation rate of the rGO-ZnSn(OH)6 composite was 93.2%,the degradation rate constant k =0.026min-1,which was 2 times and 4.3 times of the pure ZnSn(OH) 6,respectively.
Wang Jiefang; Zhang Duo; Guo Qiaoneng; Liu Zhongxia; Wang Mingxing
Abstract: The effect of zinc on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy was investigated using optical microscope,differential thermal scanners,scanning electron microscope,hardness and tensile property test.The results showed that the addition of Zn did not change the morphology and composition of the second phase,the best homogenization treatment of the alloy was 500 ℃ × 24 h.The peak aging hardness was increased from 169 MHV to 182 MHV,the tensile strength and yield strength at room temperature were increased by 23 MPa and 27 MPa,respectively.And the elongation of the alloy was still kept at a high level of 14%.The reason could be the solution of the zinc increase the crystal lattice distortion,and then lead to the improvement of the mechanical properties.
Wu Jinxing; Wang Chao; Wang Mingqiang; Liu Yanhui; Li Yafei
Abstract: In order to improve the comprehensive performance of convection in tubes inserted with twisted tapes,in the developed 3-edge twisted tape,a simulation was carried out to examine the comprehensive characteristics of single phase convection in circular tubes inserted with twisted tapes,including typical twisted tape,grid spiral twisted tape and 3-edge twisted tape.With water as the working fluid,the behavior of fluid flow and heat transfer of these different types of twisted tapes with the same twist ratio y =2.0 were studied.The RNG k-ε turbulence model was chosen for the Reynolds number ranging from 5 000 to 30 000.The nusselt number(Nu),friction factor(f) and comprehensive performance evaluation factor(η) were calculated and compared with those of a plain tube in the same condition.The results showed that the comprehensive performance of 3-edge twisted tape was better than plain tube,the tubes with typical twisted tape and grid spiral twisted tapes insert.
Fu Zhen1,Shen Wanqing1,Kong Zhifeng2,Zhang Chao2
Abstract: With the fact that plasticizers were used successfully in plastic products to improve the low-temperature flexibility of asphalt binder,two kinds of plasticizer are selected in this paper to study the impact of two plasticizers on asphalt.In this paper,4 different dosages of the two plasticizer totally 8 dosages were put into asphalt to study the performance of asphalt binders by several routine tests including the penetration,softening point,ductility,viscosity,measuring-stress ductility and elasticity resuming.And the modification effect was evaluated in the aspect of temperature sensitivity,high temperature and low temperature,elastic recovery and aging.The test results showed that the plasticizers did help significantly in the low-temperature performance of the modified asphalt binders,also in the facts of temperature sensitivity,anti-aging ability and elasticity resuming,but not in high-temperature performance.In general,the plasticizer DOM was better than DOP in improving the properties of asphalt binders.
Xing Longjie Huang Yanfang Wang Wenjuan Han Guihong Liu Jiongtian
Abstract: In order to make use of lignite,the dissolution of HA in lignite with the change of soaking temperature,and the content of total acid group,hydrophilieity and charge of lignite surface after dissolution was investigated.The result showed that the capacity of dissolution of HA in lignited increased with the increase of soaking time and temperature.When soaking temperature was 50 ℃,soaking time 2 h,the capacity of HA was 15.636 mg/L.The analysis of FTIR was used.And the lignite after dissolution was characterized.The total acid groups,contact angle and zeta-potential of lignite after dissolution were determined.This research showed that the oxygen-containing functional groups of lignite after dissolution decreased from 2.768 mmol/g to 2.431 mmol/g,the contact angle increased from 100.75° to 105.33°;and the Zeta-potential increased from-49.01 mV to-46.14 mV with the increase of temperature.
Han Xiuli1,Song Ajuan2,Bai Jing1,Fang Shuqi1
Abstract: The lotus leaf chemically modified by triethylenetetramine was prepared as adsorbent to remove hydroquinone from aqueous solution.Response surface methodology was applied to optimize the experimental conditions.The optimal conditions were reaction temperature of 81.8 ℃,reaction time of 3.8 h and ratio of triethylenetramine and material of 3 mL · g-1.A series of factors affecting the adsorption process such as the contact time,adsorbent dosage and pH were investigated.The isothermal process of hydroquinone was described very well by the Langmuir and Temkin models,the maximum adsorption capacity onto modified lotus leaf was 1.384 mmol · g-1 at the temperature of 313 K.Thermodynamic parameters indicated that the adsorption process conformed to spontaneous and endothermic process.
Su Jinrui, Nan Yichen, He Hao, Zhao Yingying
Abstract: The BaCe0.8In0.1Y0.1O3-δ (BCIY and Ta doped BaCe0.7Ta0.1In0.1Y0.1O3-δ (BCTIY) electrolyte powders were successfully synthesized by citrate combustion and solid phase reaction method in this paper.Under the 200 MPa pressure dry-pressing molding,the electrolyte flakes were obtained by sintered at different temperatures.The phase of samples was analysed by the x-ray diffraction (XRD);the microstructure was obtained by scanning electron microscope (SEM).The electrochemical performance was measured by the electrochemical workstation.The characterization of XRD,SEM and electrochemical workstation demonstrated BCIY and BCTIY both with a single perovskite structure after 5 h at 1 000℃ calcination.Moreover,BCIY and BCTIY Could be dense sintered under 1 250℃ and 1 350℃,respectively.In addition,the conductivity of BCTIY is a little smaller than that of BCIY in the air and humid H2.Meanwhile,the chemical stability of BC-TIY is superior to that of BCIY in CO2 and boiling water environment.These results indicated that BCTIY could be stable electrolyte materials applied in intermediate temperature solid oxide fuel cells.
Fan Zhonglei; Ma Xiangyu; Li Ruirui; Qiao Huanhuan
Abstract: Surface ion-imprinted poly (allylamine)-silica material (IIP-PAA/SiO2) was synthesized by surface imprinting technique.The effect of sorbent concentration (W0) on Cu(Ⅱ) adsorption was studied using batch experiments.The results showed that the adsorption system exhibited a significant sorbent concentration effect,and adsorption isotherms declined as W0 increased.Results obtained from the tests also indicated that the equilibrium adsorption capacity Qe was not a single function of the equilibrium ion concentration Ce but a function of both Ce and W0.A revised Langmuir model was obtained according to the factor of Ce/W0.Its applicability was examined,and the result showed that the equilibrium capacities under various particle concentrations could be described well by the revised Langmuir model.
Dong Fangfang Shang Zhigang Liu Xinyu Wanhong
Abstract: In order to overcome the problems as low signal-to-noise ratio (SNR) of LFP and difficulty in identifying encoding time window when extract the features of motion intention,a method that combines independent component analysis (ICA) with Wavelet was presented to extract the features of turning.Firstly,the motion videos of animals were analyzed and the time-frequency diagrams of LFP were plotted to determine the time window of signal which encoded the motion information.Then,ICA was used to increase the SNR of LFP.Thirdly,the encode bands of LFP were extracted by wavelet method as well as the encode features were extracted by sliding time window method.Lastly,k-nearest neighbor method was used to classify the encode features.And via 1 000 times cross validation the precision was(92.35 ±5.87)%,the results showed that it could decode reliably the motion intention of animals.
Wang Jinfeng1,Meng Xufei1,Wang Zheng2,Yang Lixi1
Abstract: The current transmission fixed cost allocation method could not ensure the complete recovery of the cost and provide economic signals,a transmission fixed cost allocation method based on AR-DEA and cooperative game was proposed.Firstly,the index system of cost allocation was constructed in consideration of power consumption,TOU power price,power quality and other factors.Then based on the data envelopment analysis,a cooperative game model was established;and the assurance region was introduced to the weight constraint;so a transmission fixed cost allocation model considering multi index weight constraints was obtained.Finally,A numerical example was used to illustrate the feasibility of this method.
Li Mengmeng; Shang Zhigang; Li Zhihui
Abstract: To reduce computational burden and improve operation efficiency of support vector machine (SVM) while ensuring classification accuracy,a fast method to filter support vectors combined with operation of projection and nearest neighbors’ selection was proposed.Considering the global characteristics of Fisher projection,it could be viewed as the approximate normal directions of SVM optimal hyperplane and filtered out a large number of non-support-vectors in this direction.The samples near the classification obtained boundary were regarded as alternative support vectors set.Neighborhood operation was combined to solve the problem that some support vectors might be filtered out mistakenly regardless of the local structure information.A number of nearest neighbors of the alternative support vectors were selected backward from the samples space to update and expand the alternative support vectors set.The sets was treated as the SVM input.The experimental results on several UCI standard data sets showed that the fast method had good generalization performance and reduced the computational burden effectively under the premise of fully guaranteed classification accuracy.
Yang Zhuo1Wang Lili1Yang Bo2Guan Chaojie1Cheng Zixia3
Abstract: The construction and transformation of power supply modes were explored researched according to the composition of the typical power supply mode in different power supply areas(A +,A,B,C,D,E) as well as future development orientation.The "smallest unit of planning year" adapted from "smallest unit of load method",was proposed at first,to make the transition program for the updating of typical power supply mode in different power supply area.Then transition schemes were economically compared and comprehensively analyzed using modified method of calculation.At last,the optimal transition path was selected to determine its development course of power supply mode by calculating.
Cheng Xian1;Chen Zhanqing2;He Zhou1;Yuan Duanlei1;Zhong Jianying1
Abstract: o decrease the transient influence caused by the switching operation of vacuum switches,the resultant force on vacuum switch in the operating period and the influence factors on operating accuracy were analyzed in this paper.Dynamic characteristics of permanent magnetic actuator in the operating processes were calculated.A self-adaptive control system for actuator,which could real-time control the excitation current and travel agency of actuator,was designed.The control system could modify action dispersion of the actuator effectively by driving IGBT to control the discharging orders of capacitors.It could also realize accurate operating at setting voltage and current phases by adding phase detection unit.Test results of the control system showed that the control system could reduce the action dispersion of vacuum switch actuator significantly,and the action dispersion was controlled within ± 500 μs.
Jiang Ming1,Zhao Hongyu2,Liu Xueliang1
Abstract: Gait analysis was one of the most focusd research fields in recent several years,and the gait parameters attracted increasing interest in clinical medicine,pedestrian navigation and so on.However,the existing gait detection methods had some shortcomings that prevented their successful use to many practical applications,the detection results of which were very sensitive to measurement fluctuations and detection parameters,and thereby characterized by poor robustness.In this paper,the mutual coupling relationship between different parameters was tested,and an adaptive gait detection method based on clustering analysis was proposed,so as to automatically yield the time heuristic threshold.The experimental results demonstrated the correctness and effectiveness of the method,and the gait detection accuracy over a large parameter space could be improved from 46.16% and 53.22% respectively to 76.13%.
Bai Guochang; Zhang Yuxin
Abstract: This paper focused on the sensorless start-up strategy of a torque motor,especially,when a motor was at standstill or very low speed.It was well known that the signal was too small or contains too many noise signals to estimate a precise rotor position.By eliminating the function of error and noise,the simplified flux linkage function method could be obtained based on the traditional winding flux linkage function method principle.The simulation model and the experimental platform based on TMS320F28335 showed that the calculation amount was decreased and the dependence on the parameter was reduced compared with the traditional method.At low speed (60 r/min),the simplified flux function method could be used to ensure the motor running smoothly by calculating the phase change.
Wang Zhichao; Ya Yangfei
Abstract: A stress analysis model of hydraulic support base on elastic floor was established based on the theory of beam on elastic foundation.The optimal variables including connecting rod force,structure size,bending moment of the cover beam,floor pressure and support efficiency were taken as five optimization objectives.Hydraulic support overall size of the design parameters were optimized under different floor conditions through the sequence quadratic planning method.The application of visualization was realized based on MATLAB/GUI visual programming.The example analysis showed that the optimization results not only could meet the design requirements but also could improve the mechanical properties.The four main mechanical parameters include the axial force of the connecting rod,the pressure of the floor and the bending moment of the cover beam decreased by 31.95% on average.
Wang Dong; Liu Yufan; Chen Xin
Abstract: In the condition of high-speed grinding,a single factor process experiment was carried out for 18CrNiMo7-6,which usually used in gear material,making grinding parameters such as wheel velocity,grinding depth and workpiece velocity variables.This study aimed to explore the effects of high-speed grinding on surface quality of experimental material from surface roughness and surface hardness,to analye the effects of grinding parameters on surface roughness and surface hardness,and to explain the varying pattern of surface roughness and surface hardness of experimental material in high-speed grinding.The results showed that surface roughness decreased with the increase of wheel velocity and increased with the increase of grinding depth and workpiece velocity;surface hardness decreased with the increase of grinding depth,and increased with the increase of workpiece velocity,but surface hardness decreased firstly and then decreased and tended to be stable finally with the increase of wheel velocity.
Yuan Xiaohong, Chen Long, Wang Yiping
Abstract: The clamping force control of continuously variable transmission was studied,and the traditional force control strategy was improved.The slip mechanism of metal belt and pulley was analyzed,with the description of the slip phenomenon.The influence of slip ratio on the belt wheel drive was studied,and the mathematical model was established by the test data.The combined simulation model based on AMESim and Simulink was established.Combined with simulation results,the new control strategy and the traditional control strategy are compared.The simulation results showed that the clamping force was reduced to the original 85%-90% with the new control strategy.The new control strategy made transmission efficiency maintained between 80% to 85%,with throttle opening increased from 10% to 50%.In extreme conditions,the slip rate control would produce a certain degree of slip rate fluctuations,which might need further improvement.
Hou Junjian; Fang Zhanpeng; He Wenbin
Abstract: The Solid Isotropic Material with Penalization (SIMP) was applied to establish the topology optimization model of constrained layer damping (CLD) structure.The minimum of displacement response was considered as the objective function and the volume fraction of constrained layer damping material as constrained conditions.The sensitivity of modal damping ratio was introduced in the sensitivity analysis of the objective function,making the sensitivity more accurate and sensible.The topology optimization model was solved by Method of Moving Asymptotes (MMA).The numerical examples demonstrated that the proposed dynamics optimization of CLD structure was of validity and effectiveness.
Zhang Jiantao Zhou Lihua
Abstract: Taking the campus canteen as the research object,the passive energy-saving design of campus canteen was analyzed and studied in the view of environmental performance-driven building design,and regional climatic conditions.In the architectural design phase,the principles and methods of environmental integration,spatial organization,interface design,simulation and optimization four aspects were consideved,Based on this case,the passive energy-saving design principles and strategies of campus canteen in Zhengzhou were generalized.
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