Journal of Jiangsu University(Natural Science Eidtion)

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Journal of Jiangsu University(Natural Science Eidtion)

	2016 Vol.37 Issue.1 Published 2016-01-10

	Article

Article

	1	Noise source identification of diesel engine based on sound pressure level and sound intensity methods
		LIU Shuai, WANG Zhong, ZHAO Yang, QU Lei, SUN Bo
		By near-field sound pressure level methed, the near-field sound pressure levels of 14 parts were measured for the four-cylinder diesel engine including cylinder cover, fuel pump, oil pan, turbocharger, air filter and so on. The contribution of each part noise to overall noise was analyzed. The sound intensity scanning method was used to measure the sound intensities of fuel pump side, exhaust side, fan side and cylinder head side of the diesel engine, and the near field noise spectrum of main noise sources was collected. The results show that the contribution rate of fuel pump noise to overall noise is 37%, and the oil pan surface radiation noise energy accounts for 22% of whole noise energy at the declared working condition. The noise peaks of fuel pump appear at the frequencies of 630 Hz and 2 000 Hz, and the radiation noise peaks of oil pan appear at every frequency band. The noise of fuel pump and the radiation noise of oil pan are the main noise sources of diesel engine, and the radiation noises of cylinder head, accessory box and crankshaft are secondary noise sources. The results by two indentification ways are consistent.
		2016 Vol. 37 (1): 1-5 [Abstract] ( 1178 ) [HTML 1KB] [ PDF 2377KB] ( 1333 )

	6	Analytical method of united brake stability of articulated vehicle
		HE Ren, SHEN Xiao-Min, XU Hang
		To study the stability of united hydraulic retarder and friction brakes, based on the ″I-β″ curve method， a new kind of ″M-N-P″ curve method was proposed to realize qualitative analysis of united brake stability of articulated vehicle， and the lock up sequence of articulated vehicle axles under different road conditions was obtained. The quantitative analysis of brake stability under various working conditions was also conducted based on the concept of brake force utilization ηb . The results indicate that when the hydraulic retarder works, the increasing of brake torque on drive axle of tractor rear axle can make it lock up in advance, and the range of adhesion coefficient shows upward trend to cause the unreasonable condition with the increasing of hydraulic retarder gear. The brake force utilization first increases with later decreasing, and it is significantly lower on low adhesion coefficient road. The hydraulic retarder applied on articulated vehicle should not work at high gear for long time and be used with caution when road surface is wet or slippery.
		2016 Vol. 37 (1): 6-11 [Abstract] ( 1914 ) [HTML 1KB] [ PDF 1650KB] ( 1343 )

	12	Effects of variable oxygen-nitrogen charging components on combustion process and emission features of diesel engine
		MEI De-Qing1, WU Han1, JIANG Shi-Yang1, QIAN Jun-Nan1, YUAN Yin-Nan2
		Charged with variable oxygen and nitrogen components as intake air, the combustion features and emission regulations of a diesel engine were analyzed. The results show that the effect of enriched nitrogen on prolonging ignition delay appears more evidently than that of enriched oxygen on shortening ignition delay. The increasing rates of all emissions show second polynomial relationship with the increasing rate of intake oxygen. From the state of nitrogen enrichment, with the increasing of intake oxygen content, the ignition delay is decreased, and the cylinder peak pressure and the maximum rate of pressure rise are increased. At the state of oxygen enrichment, the effects of oxygen increasing on the reduction of HC, CO and smoke are weakened gradually. At the state of nitrogen enrichment, HC, CO and smoke are worsened sharply. NOx emissions behave a rapid rise at oxygen enrichment state but with slow decline at nitrogen enrichment state. Restricted by oxygen providing, the influence of intake oxygen volume fraction variation on CO and smoke emissions is enhanced at large load. At small load, the intake oxygen volume fraction has marked impact on in-cylinder temperature, which leads to more sensitivities of HC and NOx emission.
		2016 Vol. 37 (1): 12-17 [Abstract] ( 1333 ) [HTML 1KB] [ PDF 1804KB] ( 1149 )

	18	Numerical simulation and experiment verification of trap capture efficiency for diesel particulate filters
		QI Ying-Jie-1, YANG Hua-Long-1, MA Yan-1, YANG Chun-Mei-1, WANG Si-Yang-2
		To develop particulate filter with high filtering efficiency, a comprehensive mathematical model of trap capture efficiency was established based on the capture theory of packed bed, and the established model was validated by Matlab. The results show that in the whole process of particulate trapping, Brownian diffusion plays a dominant role. The reduced exhaust flow rate and the improved exhaust temperature can improve the diffusion coefficient and the capture Brownian integrated capture coefficiency, while the exhaust flow rate and the exhaust temperature have slight effect on the straight intercept capture mechanism. When the particle size is less than 100 nm, the integrated capture coefficient increases rapidly with the decreasing of particle size， and the number has little difference with the Brownian diffusion coefficient. When particle size is greater than 100 nm, the straight intercept capture mechanism is enhanced, and the comprehensive capture coefficient decreases slowly with the increasing of particle size. When the particle size is from 100 nm to 500 nm, the capture mechanisms compete each other to obtain the minimum value of comprehensive capture coefficient.
		2016 Vol. 37 (1): 18-23 [Abstract] ( 1303 ) [HTML 1KB] [ PDF 2370KB] ( 1320 )

	24	Effects of liquid-vapor surface tension coefficient on two-phase flow and heat transfer in rectangular microchannel
		WANG Ying-Hui, SHAO Nan, WANG Ru, ZHAO Ling-Xiao
		To investigate the effects of surface tension on flow boiling of water solution, in a 0.2 mm×20.0 mm rectangular microchannel, the heating working condition by uniform heat flux of 200 kW?m-2 was numerically simulated. Volume of fluid multiphase flow model and a special user defined function were used to establish the two-phase flow boiling model. The geometric reconstruction scheme was adopted to capture the liquid-vapor interface. The effects of liquid-vapor surface tension coefficient σ on the behaviors of bubbles growth, coalescence and evolution related to two-phase flow pattern were investigated under the conditions of three different values of surface tension coefficient of 0.035, 0.045 and 0.059 N?m-1 (pure water). The stability of two-phase flow and the features of heat transfer were also discussed and analyzed. The results show that compared with σ of 0.059 N?m-1, the size of bubble decreases nearly 1/2 when σ equals to 0.035 N?m-1. The pressure drop fluctuation is reduced by 2.1 kPa, and the superheated regions with wall temperature Tw more than 400 K is decreased by 3/4 to guarantee the reliability of heat dissipation in microchannel. The highest superheated temperature of Tw is reduced from 1 600 K to 1 000 K. The bubbles evolution in microchannel is depended upon the surface tension coefficient at a large extent, while bubbly flow, slug bubble flow and elongated bubble flow occur regularly in microchannel. The small surface tension coefficient can result in stable liquid-vapor two-phase flow to improve the heat transfer reliability of flow boiling in microchannel.
		2016 Vol. 37 (1): 24-30 [Abstract] ( 1111 ) [HTML 1KB] [ PDF 3154KB] ( 1340 )

	31	Effect of surfactant on removal of fine particles by fine water mist
		WANG Jun-Feng, MO Xiao-Jian, ZHANG Zheng, CHU Jin-Jing
		To explore the adsorption mechanism of fine particles by fine water mist, the experiment of dust removal characteristics by fine water mist with surfactant was conducted by the spray system with air blowing structure. The effects of droplet size, surfactant concentration and wind speed on the dust control rate were discussed. The experimental results show that with the decreasing of droplet size, the dust control rate increases first with latter decreasing, and there is dust control rate peak. The surfactant solution can markedly improve the rate for different droplets size. The smaller the droplet size is, the more marked the effect is. With the increasing of surfactant mass concentration, the dust control rate is mainly on the rise. The low wind speed is conducive to dust control rate for both pure water and water with surfactant.
		2016 Vol. 37 (1): 31-34 [Abstract] ( 1056 ) [HTML 1KB] [ PDF 1542KB] ( 1231 )

	35	Unstability of flow around rigid circular cylinder with one degree of freedom
		LI Chang-Feng, WANG Li, WANG Hong-Yu, LIU Yan-Feng, LI Lei-Xiao
		Based on OpenFOAM software with k-ω SST turbulence model and 6 degree-of-freedom motion grid solver, three-dimension numerical simulations were conducted for a flow of subcritical region around one degree of freedom moving cylinder. The cylinder lift coefficient, drag coefficient, motion trajectory and flow solid coupling pattern were investigated under different initial flow fields. Using C++object oriented programming, the experimental data and theoretical analysis were compared to verify the reliability of the turbulence model and the calculation results. The calculation results show that structured mesh decomposition method and k-ω SST turbulence model are accurate to solve the problem of flow around a circular cylinder. The cylinder with the freedom perpendicular to the flow direction is unstable. The stability strength and the deviating direction are related to the initial flow state. The fluid solid coupling changes the frequency of lift coefficient and enhances the cylinder deviating.
		2016 Vol. 37 (1): 35-38 [Abstract] ( 1305 ) [HTML 1KB] [ PDF 2953KB] ( 1391 )

	39	Numerical simulation of particle rotation characteristics in impinging stream
		WANG Zhu-Liang, CHEN Wei, GONG Jun, DU Min
		To simulate particle rotation characteristics, a gas-solid impinging stream mathematical model was established by DSMC method with the consideration of particles rotation. The experimental data were used to verify the proposed model. The effects of initial velocity, flow rate and diameter on particles rotation characteristics were analyzed. The results show that particle rotation mainly generates in impinging area. The average rotation rate is increased with the increasing of initial velocity, feed rate and diameter of particles.
		2016 Vol. 37 (1): 39-43 [Abstract] ( 1297 ) [HTML 1KB] [ PDF 2183KB] ( 1161 )

	44	Design method and fatigue strength analysis of eccentric-noncircular gear transmission mechanism
		QIAN Meng-Bo-1, YU Gao-Hong-2, ZHANG Xue-Fen-1, CHU Bing-Bin-1
		The design processes and methods of eccentric-noncircular gear transmission mechanism were introduced in detail.Based on the geometric model of eccentric-noncircular gear and section-curve closed condition， the design program and the profile of the eccentric-noncircular gear were realized by VB software to conduct 3D modeling，assembly and simulation. The fatigue strength was analyzed on the fracture phenomenon of noncircular gear.Through the stress analysis, the maximum stress of meshing transmission parts in the process of eccentric noncircular gear transplanting mechanism was deduced.To discuss the reason of noncircular gear failure and provide measures to avoid the failure, the material composition of powder-metallurgy gear and the processing technology were analyzed.
		2016 Vol. 37 (1): 44-48 [Abstract] ( 1259 ) [HTML 1KB] [ PDF 2668KB] ( 5613 )

	49	Grading actuator simulation and optimization analysis of free pallet conveying fruit
		DI Bu-Jin, XU Hui-Rong, WANG Jian-Ping
		To improve the accuracy of delicate fruit production line for fruit grading and reduce the blindness of scan debugging, the virtual prototype simulation model was established in ADAMS software. Through the quadratic general rotary design experiments with three factors and three levels at virtual prototype, the effects of rotating actuator angle， conveyor belt speed and fruit weight on the fruit grading accuracy were discussed to obtain the regression equation of the accuracy for fruit classification.The process parameters of vulnerable fruit production line for fruit grading were obtained by the regression equation and used to conduct verification test. The results show that when the weight of fruit ranges from 236.3 to 287.7 g, the fruit grading accuracy is 86.7%.When fruit weight ranges from 247.8 to 275.2 g, the fruit grading accuracy rate reaches 100%.
		2016 Vol. 37 (1): 49-54 [Abstract] ( 1666 ) [HTML 1KB] [ PDF 3088KB] ( 1532 )

	55	Independent variable pitch control based on speed feedback for reducing wind turbine fatigue load
		SU Yong-Qing, LI Fei-Long, YUE Ji-Guang, CHEN Feng
		According to the aerodynamic principles, the blade stress situation during the rotation process was analyzed. In order to reduce the fatigue load by wind turbine, a new PID wind turbine individual pitch control method was proposed with speed feedback as compensation angle for each blade. The simulation results show that the new method can keep output power stable and decrease blade vibration speed effectively, and the difference of vibration displacement is reduced to lead to the great reduction of fatigue load by wind turbine. The reliability and the life of wind turbine are improved by the proposed method.
		2016 Vol. 37 (1): 55-59 [Abstract] ( 1450 ) [HTML 1KB] [ PDF 2354KB] ( 1211 )

	60	Simulation of permanent magnet synchronous motor vector control for electric vehicles considering magnetic saturation
		XIE Ying, GE Hong-Yan, LIAN Guo-Yi
		To solve the problem that the motor parameter was selected singly in motor weakening control system without consideration of motor parameter changes under different conditions, and resulting in the underutilized motor performance, the effects of dq axis inductance changes on the weakening control system were investigated. Taking permanent magnet synchronous motor for electric vehicles as example, the models were established respectively for 2D electromagnetic field analysis and mathematical analysis in different vector control methods. According to the dq axis flux equations, the dq axis inductances with different d-axis and q-axis currents were calculated by finite element method with consideration of dq axis magnetic cross-coupling impact on magnetic saturation. The obtained inductances were substituted into the system simulation model in vector control of id=0 control and weakening control. The features of motor control were compared under the conditions with consideration and without consideration of magnetic saturation in different control methods. The results show that the motor performance with consideration of magnetic saturation in weakening control system is more fully utilized with accurate simulation of motor performance.
		2016 Vol. 37 (1): 60-66 [Abstract] ( 1377 ) [HTML 1KB] [ PDF 3006KB] ( 1842 )

	67	Combinatorial testing approach and experiment based on matrix repeat degree
		CHEN Jin-Fu-1, SU Chen-Fei-1, 2 , ZHAO Xiao-Lei-1, HUANG Ru-Bing-1, CHEN Chang-Chuan-3
		To improve the efficiency of combinatorial testing and reduce the numbers of test cases of combinatorial test, based on matrix repeat degree, an algorithm was proposed to generate the minimum numbers of test cases. An input matrix was generated based on the numbers of factors and the value numbers of each factors. The initial solution matrix was generated by comparing repeat degree of input matrix. The solution matrix was verified to decide whether all combinations of factors were covered, and the uncovered combinations of factors were recorded. To obtain the final solution matrix, the greedy algorithm was used to cover the uncovered combinations of factors. Each row of the solution matrix was a valid test case. The proposed approach was compared with the common combinatorial testing tools of ACTS and PICT for low factors cover, high factors cover and various different parameters. The experimental results show that the proposed approach can generate less numbers of test cases to ensure that all factor combinations are covered. The proposed approach is superior to ACTS and PICT, which proves to be feasible and effective.
		2016 Vol. 37 (1): 67-73 [Abstract] ( 943 ) [HTML 1KB] [ PDF 1720KB] ( 1417 )

	74	Research progress and analysis on future internet architecture
		CHENG Ke-1, 2 , YU Feng-1, PAN Lei-1, GAO Shang-1, QI Yun-Song-1
		The traditional network architecture TCP／IP model is focused on host inter-connect and data reachable. Internet design principles of best-effort, end-to-end and connectionless are main factors on internet development, while it is hard to adopt innovations in network architecture and service provisioning for the next generation network demands of high performance, security, controllability and manageability. It is very necessary to investigate the next generation network architecture. Based on the analysis of existing problem in TCP／IP architecture, the related work done by several important research projects of next generation internet was introduced in detail, and the requirement objects and design principles of architecture model were provided according to the summary of existing research results. The categories, surveys and analysis were completed on the presented next-generation internet architecture to discuss the future research.
		2016 Vol. 37 (1): 74-84 [Abstract] ( 1384 ) [HTML 1KB] [ PDF 2085KB] ( 1720 )

	85	Face recognition based on LBP preprocessing and sub-image feature sampling
		WANG Jin, JIE Xiao-Feng, HU Ming-Xing, DENG Xin, CHEN Qiao-Song
		To solve the problems that the random subspace method had poor robustness to local variation of human face images, high computational complexity using multiple random sampling and fixed sampling rate, a human face recognition method was proposed based on the local binary patterns (LBP) and sub-image based feature sampling. The human face images were preprocessed by LBP technology to obtain LBP texture images. The sub-image division was performed on LBP texture images. The random feature sampling was completed based on sub-images in combination with random subspace method, and the based classifiers were trained by the randomly sampled features to build an ensemble of base classifiers. The multi-scale analysis was utilized to perform layered random sampling and divide multiple random samplings into layers with different sampling rate for each layer. The feature subsets with different dimensionalities were obtained with reduced total numbers of features, and the variety among based classifiers can be enhanced by cascade ensemble technology. The experiments were completed on the four face databases of ORL, Yale, Extended Yale B and CMU PIE. The results show that the proposed human face recognition method can achieve high runtime efficiency with high accuracy.
		2016 Vol. 37 (1): 85-91 [Abstract] ( 1380 ) [HTML 1KB] [ PDF 2466KB] ( 1466 )

	92	Influence of construction waste composite powder on mechanical and shrinkage properties of cement stabilized aggregate
		XUE Cui-Zhen, SHEN Ai-Qin, WAN Chen-Guang, ZHANG Ming-Hu
		In order to alleviate semi-rigid base cracking, the mechanical and shrinkage properties of cement stabilized aggregate were investigated with different construction waste composite powder materials (CWCPM) dosage. The improved effect of CWCPM on the microcosmic mechanism of cement stabilized aggregate was analyzed through DSC-TG thermal analysis. The results show that the 28 d unconfined compressive strength and the 90 d flexural strength of the specimens are improved by CWCPM. The shrinkage performance of cement stabilized aggregate was also improved. The CWCPM has good filling effects to improve the compactness of the cement base material. The powder materials of CWCPM have good superposition and volcano ash effects, which improves the composition of cement hydration products to reduce Ca(OH)2 content.
		2016 Vol. 37 (1): 92-96 [Abstract] ( 952 ) [HTML 1KB] [ PDF 2085KB] ( 1473 )

	97	Influencing factors of stop-hole method for fatigue crack of steel box girder
		JI Bo-Hai, YUANZHOU Zhi-Yuan, LIU Tian-Jia, FU Zhong-Qiu
		The linear elastic finite-element solid model with crack was established with consideration of different drilling-hole parameters of diameter, location and angle in steel box girder. The stress variations at the hole-edge and along the thickness direction were obtained, and the effects on stress reduction were compared. The proportion of stop-hole influencing factors was discussed based on different stress reduction in different drilling-hole parameters. The results show that large stop-hole cannot effectively retard crack extension. The stress at the hole-edge is 25% larger than that inside, which indicates that the crack becomes easier to produce at surface. The stop-hole needs to be drilled at the center of crack edge to reduce stress contribution, and the stop-hole with a certain eccentricity or angle can improve stress distribution and effectiveness.
		2016 Vol. 37 (1): 97-102 [Abstract] ( 1160 ) [HTML 1KB] [ PDF 2403KB] ( 1680 )

	103	Uncertainty analysis of prestressing loss of continuous rigid frame bridge based on response surface method
		ZHOU Jian-Ting, XIN Jing-Zhou, WANG Yu, LI Zhi-Gang
		The prestressing loss calculated by the current code of China can′t fit actual engineering ideally. To solve the problem，with the considerations of construction factor, materials performance and environment condition, the response surface method was employed for uncertainty analysis of prestressing loss of large span continuous rigid frame bridge. Taking a continuous rigid frame bridge as project background, eight main structure parameters and Bucher design method were adopted to conduct the experimental design with three levels. The response surface models without influence of cross-terms were established to express the complex implicit relationship between prestressing loss and random parameters by approximate explicit functions. The significance test and the accuracy test on response surface models were carried out using F test and corrected determination coefficient. The significance analysis of basis function based on stepwise regression and the sensitivity analysis of parameters were conducted by the Spearman rank correlation coefficient. The prediction of prestressing loss in the sense of probability was realized by Monte Carlo sampling analysis.
		2016 Vol. 37 (1): 103-109 [Abstract] ( 967 ) [HTML 1KB] [ PDF 1527KB] ( 1213 )

	110	Preparation and application of epoxidized magnetic silica nanoparticles
		SUN Jun-1, ZHANG Jin-Cheng-1, JIANG Meng-Meng-2, MA Hai-Le-1
		Fe3O4 magnetic nanoparticles were modified by surfactants of polyethylene glycol 6000 (PEG 6000) and sodium dodecyl benzene sulfonate (SDBS). The epoxidized magnetic silica nanoparticles were obtained by sol-gel method and ethanol-acid method. Lysozymes was immobilized on the epoxidized magnetic silica nanoparticles. The results show that the enzyme recovery is 78.6 % with lysozyme loading of 114.9 mg?g-1 when the immobilizing time is 2 h with buffer of pH 8.0 and initial lysozyme concentration of 1.0 g?L-1. The immobilized lysozymes have improved storage stability.
		2016 Vol. 37 (1): 110-114 [Abstract] ( 1137 ) [HTML 1KB] [ PDF 1781KB] ( 1666 )

	115	Hybrid algorithm of VNS-CRO for construction process optimization
		JIANG Yu-Yi-1, SHAO Zhi-Qing-1, CAI Ning-2, ZHANG Huan-Huan-1
		To solve the absence of heterogeneous resource systems for construction task sublet and schedule in current research works, a hybird algorithm of variable neighbourhood search-chemical reaction optimization (VNS-CRO) was proposed. The building information modeling (BIM) technology was combined with the theory of task scheduling on heterogeneous systems to construct task schedule and sublet on heterogeneous resource systems. Based on directed acyclic graph (DAG) model, heterogeneous resource system model and constrained critical path strategy, the variable neighbourhood search method with balanced neighbourhood structure was utilized in initiation and optimizing super molecule for improving optimization capability. The data of Chengxiang Road construction project in Shanghai was used to conduct simulation experiments. The experimental results prove the effectiveness, robustness and advantages of the proposed algorithm.
		2016 Vol. 37 (1): 115-120 [Abstract] ( 1263 ) [HTML 1KB] [ PDF 2017KB] ( 1635 )

	121	Synthesis of alkali metal complexes of Cyclen derivatives
		WANG Ai-Jian-1, 2 , ZHAO Wei-2, SUN Xiao-Qiang-3
		The tetra-N-alkylations of 1,4,7,10-tetraazacyclododecane(Cyclen) derivative 1,4,7,10-tetrakis(2-((4-methoxy) phenoxy)ethyl)-1,4,7,10-tetraazacyclododecane 2 with pendant-armed benzene was designed and prepared with one Cyclen base and four hydroquinone groups of benzene ring. Cyclen base is easily to coordinate with metal ion, and hydroquinone groups can form π-electron-rich cavity by stacking interaction. Two complexes of 3 and 4 were prepared by the reactions of 2 with LiBr and LiCl through an improved synthetic technique. The structure was confirmed by 1H NMR. The chemical shifts of the peaks and fluorescence spectra of 1, 2, 3 and 4 were investigated. The results show that hydrogen atoms of NCH2CH2N in 3 and 4 Cyclen unit are split into two to increase the fluorescence intensity obviously.
		2016 Vol. 37 (1): 121-124 [Abstract] ( 898 ) [HTML 1KB] [ PDF 1413KB] ( 1097 )

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