2014 Vol. 29, No. 2
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2014, 29(2)
:1-4.
doi: 10.3969/j.issn.2095-476X.2014.02.001
Abstract:
The effects of foaming agent,additive and curing agent content on tensile strength,rupture elongation and apparent density of foaming silicone were studied by the orthogonal experiment.The optimal formula for foaming silicone were 100 copies of base adhesives,3 copies of foaming agents,2 copies of additives,and 2.5 copies of curing agents.The related mechanical properties and thermal properties of the above four formulae were investigated by scanning electron microscopy(SEM),multifunctional tensile machine,and hot disc instrument.Results presented that the optimum formula had moderate mechanical properties,well defined and dispersed inner pores,and desired thermal insulation performance.
The effects of foaming agent,additive and curing agent content on tensile strength,rupture elongation and apparent density of foaming silicone were studied by the orthogonal experiment.The optimal formula for foaming silicone were 100 copies of base adhesives,3 copies of foaming agents,2 copies of additives,and 2.5 copies of curing agents.The related mechanical properties and thermal properties of the above four formulae were investigated by scanning electron microscopy(SEM),multifunctional tensile machine,and hot disc instrument.Results presented that the optimum formula had moderate mechanical properties,well defined and dispersed inner pores,and desired thermal insulation performance.
2014, 29(2)
:5-7.
doi: 10.3969/j.issn.2095-476X.2014.02.002
Abstract:
Al-doped ZnO nanosheets were prepared by the hydrothermal method,using tartaric acid as shape controling agent and zinc acetate and urea as doping source.The products were characterized by XRD and SEM.The gas sensing properties of as-prepared products to acetone,methanol,ethanol,isopropanol,n-butanol and DMF were also studied,respectively.The results showed that 3% Al-doped product had a smaller grain size and a multilayered nanosheet and flower morphology.The as-synthesized nanomaterials had good response to acetone.
Al-doped ZnO nanosheets were prepared by the hydrothermal method,using tartaric acid as shape controling agent and zinc acetate and urea as doping source.The products were characterized by XRD and SEM.The gas sensing properties of as-prepared products to acetone,methanol,ethanol,isopropanol,n-butanol and DMF were also studied,respectively.The results showed that 3% Al-doped product had a smaller grain size and a multilayered nanosheet and flower morphology.The as-synthesized nanomaterials had good response to acetone.
2014, 29(2)
:8-10.
doi: 10.3969/j.issn.2095-476X.2014.02.003
Abstract:
In order to improve the comprehensive mechanics performance of AZ91 magnesium alloy which was used as car's material,metal La was added in AZ91 magnesium alloy,and specimens were prepared by powder metallurgy method.The influence of La on microstructure,hardness and compression performance of AZ91 magnesium alloy specimens was studied using metallographic electronic microscope,hardness tester,universal tension and compression testing machine.The experimental results showed that when the addition amount of La was 1.2%,the specimens' mechanical performance was best:hardness 67.1 HV,compressive strength 115.8 MPa,which increased respectively by 20.0% and 29.5% compared with the AZ91 magnesium alloy substrate,and the grain refinement effect of AZ91 magnesium alloy was the best at the same time.
In order to improve the comprehensive mechanics performance of AZ91 magnesium alloy which was used as car's material,metal La was added in AZ91 magnesium alloy,and specimens were prepared by powder metallurgy method.The influence of La on microstructure,hardness and compression performance of AZ91 magnesium alloy specimens was studied using metallographic electronic microscope,hardness tester,universal tension and compression testing machine.The experimental results showed that when the addition amount of La was 1.2%,the specimens' mechanical performance was best:hardness 67.1 HV,compressive strength 115.8 MPa,which increased respectively by 20.0% and 29.5% compared with the AZ91 magnesium alloy substrate,and the grain refinement effect of AZ91 magnesium alloy was the best at the same time.
2014, 29(2)
:11-14.
doi: 10.3969/j.issn.2095-476X.2014.02.004
Abstract:
By extraction of the independent components (IC) from the ultraviolet-visible (UV) spectrum of simulated mixtures of food colorants disolved in water and beverage using kernel independent component analysis (KICA),the UV-KUA-SVR model were established by support vector regressing (SVR) using the IC's coefficients.This model can be used to simultineously determine multiple colorants,i.e.lemon yellow,sunset yellow,red temptation,amaranth,carmine,and brilliant blue,with the relative standard deviations (RSDs) are 1.5%,2.2%,2.0%,2.5%,2.6%,and 1.2%,respectively,the limits of detection (LOD) are 0.5 mg·L-1,0.5 mg·L-1,0.5 mg·L-1,1.0 mg·L-1,1.0 mg·L-1 and 0.5 mg·L-1,respectively.
By extraction of the independent components (IC) from the ultraviolet-visible (UV) spectrum of simulated mixtures of food colorants disolved in water and beverage using kernel independent component analysis (KICA),the UV-KUA-SVR model were established by support vector regressing (SVR) using the IC's coefficients.This model can be used to simultineously determine multiple colorants,i.e.lemon yellow,sunset yellow,red temptation,amaranth,carmine,and brilliant blue,with the relative standard deviations (RSDs) are 1.5%,2.2%,2.0%,2.5%,2.6%,and 1.2%,respectively,the limits of detection (LOD) are 0.5 mg·L-1,0.5 mg·L-1,0.5 mg·L-1,1.0 mg·L-1,1.0 mg·L-1 and 0.5 mg·L-1,respectively.
2014, 29(2)
:15-18.
doi: 10.3969/j.issn.2095-476X.2014.02.005
Abstract:
With DPPH radical-scavenging rate as the indicator, the effects of temperature, time, pH value and substrates mass ratio on the antioxidant activity of black garlic extract were studied by using the uniform design.The result showed that the pH value had a significant influence (p<0.05) on the antioxidant activity of black garlic extract, and the optimal extracting conditions were temperature 40℃, retention time 30 min, pH=3.0 and mass ratio of black garlic to deionized water 1 GA6FA 25 (g GA6FA mL).Under these conditions, the DPPH radical-scavenging rate was 92.65%, which had a relative error of 3.59% to the theoretical value.
With DPPH radical-scavenging rate as the indicator, the effects of temperature, time, pH value and substrates mass ratio on the antioxidant activity of black garlic extract were studied by using the uniform design.The result showed that the pH value had a significant influence (p<0.05) on the antioxidant activity of black garlic extract, and the optimal extracting conditions were temperature 40℃, retention time 30 min, pH=3.0 and mass ratio of black garlic to deionized water 1 GA6FA 25 (g GA6FA mL).Under these conditions, the DPPH radical-scavenging rate was 92.65%, which had a relative error of 3.59% to the theoretical value.
2014, 29(2)
:19-22,61.
doi: 10.3969/j.issn.2095-476X.2014.02.006
Abstract:
Using 6 melon varieties "xinshiji", "meinong No.1", "xinminshi No.11", "qingbianhuanghou", "shabaiNo.3" and "xinyulu".As materials,with 0 mmol/L,50 mmol/L,100 mmol/L,150 mmol/L,200 mmol/L,250 mmol/L,300 mmol/L NaCl concentrations as treatments,the research investigated the effects of different salt concentrations on melon seed germination and seedling growth and development.The results showed that:concentration ≤50 mmol/L promoted the germination and the growth of seedling.With the increase of NaCl concentration,germination process was delayed.Relative germination index,relative vitality index,radicle growth,seedling height,shoot dry weight,lateral root number were all decreased as NaCl concentration increased.The results of salt-resistance index showed that salt-tolerant ability of 6 melon varieties from big to small was"meinong No.1", "xinminshi No.1", "shabai No.3", "qingbianhuanghou", "xinshiji", "xinyulu".
Using 6 melon varieties "xinshiji", "meinong No.1", "xinminshi No.11", "qingbianhuanghou", "shabaiNo.3" and "xinyulu".As materials,with 0 mmol/L,50 mmol/L,100 mmol/L,150 mmol/L,200 mmol/L,250 mmol/L,300 mmol/L NaCl concentrations as treatments,the research investigated the effects of different salt concentrations on melon seed germination and seedling growth and development.The results showed that:concentration ≤50 mmol/L promoted the germination and the growth of seedling.With the increase of NaCl concentration,germination process was delayed.Relative germination index,relative vitality index,radicle growth,seedling height,shoot dry weight,lateral root number were all decreased as NaCl concentration increased.The results of salt-resistance index showed that salt-tolerant ability of 6 melon varieties from big to small was"meinong No.1", "xinminshi No.1", "shabai No.3", "qingbianhuanghou", "xinshiji", "xinyulu".
2014, 29(2)
:23-26.
doi: 10.3969/j.issn.2095-476X.2014.02.007
Abstract:
To investigate the application of multi-bioenzyme to treat discarded tobacco leaf for making flavor and checking product performance,the concentration of cellulose and protease were optimized firstly.After enzymolysis,brown sugar,propanediol and acetaldehyde were added to the concentrated hydrolysate solutions for Maillard reaction to prepare the flavor.The components of the flavor was tested by using GC-MS analysis,and its sensory effects were evaluated.The result showed:1)The optimal conditions were celluzyme 1 000 U/g,protease 5 500 U/g.2)The flavor could reduce irritation and coordination fragrance.3)GC-MS analysis showed that 38 main volatile components in the flavor,including 3-hydroxy-β-damascenone,megastigmatrienone,2,5-dimethyl pyrazine,and ethyl octanoate,gave more contribution to the tobacco flavor substances.
To investigate the application of multi-bioenzyme to treat discarded tobacco leaf for making flavor and checking product performance,the concentration of cellulose and protease were optimized firstly.After enzymolysis,brown sugar,propanediol and acetaldehyde were added to the concentrated hydrolysate solutions for Maillard reaction to prepare the flavor.The components of the flavor was tested by using GC-MS analysis,and its sensory effects were evaluated.The result showed:1)The optimal conditions were celluzyme 1 000 U/g,protease 5 500 U/g.2)The flavor could reduce irritation and coordination fragrance.3)GC-MS analysis showed that 38 main volatile components in the flavor,including 3-hydroxy-β-damascenone,megastigmatrienone,2,5-dimethyl pyrazine,and ethyl octanoate,gave more contribution to the tobacco flavor substances.
2014, 29(2)
:27-30.
doi: 10.3969/j.issn.2095-476X.2014.02.008
Abstract:
In order to determine the content of di(ethylene glycol) dibenzoate(DEDB) in water-based emulsion adhesives for tobacco,the adhesives were extracted separately with n-hexane,cyclohexane,ethyl ether,2,2,4-trimethylpentane,and determined by GC-MS under selected ion monitoring mode.The results showed that oscillating time 40 min and extraction volume 10 mL were preferable duration for n-hexane extraction by adding 1 mL water into the sample;the calibration curves of the DEDB exhibited good linear relations(R2=0.999 4), the limits of detection 0.04 μg/mL,RSD=4.98%,and the recoveries ranged from 97%~101%.
In order to determine the content of di(ethylene glycol) dibenzoate(DEDB) in water-based emulsion adhesives for tobacco,the adhesives were extracted separately with n-hexane,cyclohexane,ethyl ether,2,2,4-trimethylpentane,and determined by GC-MS under selected ion monitoring mode.The results showed that oscillating time 40 min and extraction volume 10 mL were preferable duration for n-hexane extraction by adding 1 mL water into the sample;the calibration curves of the DEDB exhibited good linear relations(R2=0.999 4), the limits of detection 0.04 μg/mL,RSD=4.98%,and the recoveries ranged from 97%~101%.
Study on flexible connection system of cigarette machine and packaging machine for cigarette factory
2014, 29(2)
:31-34.
doi: 10.3969/j.issn.2095-476X.2014.02.009
Abstract:
Aiming at the problems of high degree of damage in the cigarette manufacturing process, higher failure rate of loading machine and unloading machine, higher cost of parts in heterotypic packaging unit of cigaretee factory, a system with flexible connection cigarette machine and packaging machine was designed.This system took storage system with YF17,a pair of three tobacco support application as the core to replace the original use of the loading machine, unloading machine, manual work, to achieve flexible connection cigarette machines and packaging machines, reduce the manual link and protect the quality of cigarettes; at the same time using the memory buffer and adjusting the flow, the packaging equipment production speed mismatch was solved and continuous speed tracking was obtained.
Aiming at the problems of high degree of damage in the cigarette manufacturing process, higher failure rate of loading machine and unloading machine, higher cost of parts in heterotypic packaging unit of cigaretee factory, a system with flexible connection cigarette machine and packaging machine was designed.This system took storage system with YF17,a pair of three tobacco support application as the core to replace the original use of the loading machine, unloading machine, manual work, to achieve flexible connection cigarette machines and packaging machines, reduce the manual link and protect the quality of cigarettes; at the same time using the memory buffer and adjusting the flow, the packaging equipment production speed mismatch was solved and continuous speed tracking was obtained.
2014, 29(2)
:35-37.
doi: 10.3969/j.issn.2095-476X.2014.02.010
Abstract:
Aiming at the problem of GD,BE and other mainstream cigarette packaging machines missing the function of defect detection and defect elimination,a set of detection device was designed based on judgment method of suspected target region.By measuring height of the cigarette case surface and simulation information dynamic calculation of detection information,and the cigarette products quality judgment was realized.The detection device had the advantages of simple installation,convenient adjustment,reliable performance.It could effectively reduce the false detection caused by the mechanical vibration and effectively improve the quality of cigarette packaging.
Aiming at the problem of GD,BE and other mainstream cigarette packaging machines missing the function of defect detection and defect elimination,a set of detection device was designed based on judgment method of suspected target region.By measuring height of the cigarette case surface and simulation information dynamic calculation of detection information,and the cigarette products quality judgment was realized.The detection device had the advantages of simple installation,convenient adjustment,reliable performance.It could effectively reduce the false detection caused by the mechanical vibration and effectively improve the quality of cigarette packaging.
2014, 29(2)
:38-43.
doi: 10.3969/j.issn.2095-476X.2014.02.011
Abstract:
Abstract:[WT]Aiming at the problem of inconvenience to carry and difficulty with power in-field electrochemical measurement,a portable cyclic voltammetry measurement system was designed based on aptamer-based biosensor developed by our laboratory.For overcoming the noise in the circuits effectively,a lock-in amplifier,potentiostat and program for phase sensitive detection were designed to extract weak signal.Experiment results showed that the system could implement cyclic voltammetry,which had higher SNR(signal noise ratio),the measurement precision of which could reach 1 μA.It had features of power saving,and simple eration,which could meet the requirement of in-field cyclic voltammetry measurement.
Abstract:[WT]Aiming at the problem of inconvenience to carry and difficulty with power in-field electrochemical measurement,a portable cyclic voltammetry measurement system was designed based on aptamer-based biosensor developed by our laboratory.For overcoming the noise in the circuits effectively,a lock-in amplifier,potentiostat and program for phase sensitive detection were designed to extract weak signal.Experiment results showed that the system could implement cyclic voltammetry,which had higher SNR(signal noise ratio),the measurement precision of which could reach 1 μA.It had features of power saving,and simple eration,which could meet the requirement of in-field cyclic voltammetry measurement.
2014, 29(2)
:44-48.
doi: 10.3969/j.issn.2095-476X.2014.02.012
Abstract:
n view of the influence of fault on the grid of double-fed wind power generator for grid side converter, using sliding mode variable structure control method, integral sliding mode variable structure control strategy was put forward to increase power feedforward compensation.According to the mathematical model of grid side converter,the control of the grid side converter used voltage oriented vector to realize the unity-power-factor for the alternating current side and the voltage control in the DC loop.Simulation results showed that this method improved the response speed of the system,overcame the effect and the voltage variable parameter.
n view of the influence of fault on the grid of double-fed wind power generator for grid side converter, using sliding mode variable structure control method, integral sliding mode variable structure control strategy was put forward to increase power feedforward compensation.According to the mathematical model of grid side converter,the control of the grid side converter used voltage oriented vector to realize the unity-power-factor for the alternating current side and the voltage control in the DC loop.Simulation results showed that this method improved the response speed of the system,overcame the effect and the voltage variable parameter.
2014, 29(2)
:49-52.
doi: 10.3969/j.issn.2095-476X.2014.02.013
Abstract:
Aiming at the problem that the tradition selective mapping (SLM) algorithm needs transmit side information,a new algorithm-reserved subcarriers-SLM algorithm was proposed,which used the technology of grouping for the subcarriers of orthogonal frequency division multiplexing (OFDM) signals.Meanwhile,it inserted side information into the location of reserved subcarriers after shifting the groups by rows,then select the lowest PAPR groups to send.The simulation results showed that the proposed algorithm didn' t need transmit side information,at same time the peak-to-average power ratio(PAPR) and complexity of the system could be effectively reduced,the bandwidth utilization was improved.
Aiming at the problem that the tradition selective mapping (SLM) algorithm needs transmit side information,a new algorithm-reserved subcarriers-SLM algorithm was proposed,which used the technology of grouping for the subcarriers of orthogonal frequency division multiplexing (OFDM) signals.Meanwhile,it inserted side information into the location of reserved subcarriers after shifting the groups by rows,then select the lowest PAPR groups to send.The simulation results showed that the proposed algorithm didn' t need transmit side information,at same time the peak-to-average power ratio(PAPR) and complexity of the system could be effectively reduced,the bandwidth utilization was improved.
2014, 29(2)
:53-57.
doi: 10.3969/j.issn.2095-476X.2014.02.014
Abstract:
The low-voltage power line noise acquisition equipment was used to collect noise data in three power environments including the student dormitory,teaching experimentation area and residential area,processing to get 10~500 kHz noise power spectrum was gotten variation tendency of the power line noise amplitude with typical communication frequency and different periods were analyzed.The results showed that:noise amplitude will decrease with the increase of the frequency;Low-frequency noise has a greater impact on the power line;During power peak periods,noise amplitude will fluctuate 10~35 dBμV.Therefore,as far as noise level,the America standard carrier frequency band of 100~450 kHz was more suitable for power line carrier communication than the European standard carrier frequency band of 3~148.5 kHz.
The low-voltage power line noise acquisition equipment was used to collect noise data in three power environments including the student dormitory,teaching experimentation area and residential area,processing to get 10~500 kHz noise power spectrum was gotten variation tendency of the power line noise amplitude with typical communication frequency and different periods were analyzed.The results showed that:noise amplitude will decrease with the increase of the frequency;Low-frequency noise has a greater impact on the power line;During power peak periods,noise amplitude will fluctuate 10~35 dBμV.Therefore,as far as noise level,the America standard carrier frequency band of 100~450 kHz was more suitable for power line carrier communication than the European standard carrier frequency band of 3~148.5 kHz.
2014, 29(2)
:58-61.
doi: 10.3969/j.issn.2095-476X.2014.02.015
Abstract:
Aiming at the problem that micro-blog had large amount of information,the coalescing hierarchical clustering algorithm was not suitable and Single-Pass clustering algorithm results was not accurate, a new algorithm SP&HC integrating hierarchical clustering algorithm and Single-Pass clustering algorithm were put forward.It used Single-Pass clustering algorithm to make the large number of micro-blog text become into the simple clustering, in order to collect some small amplitude and high cohesive theme topic.This greatly streamlined the content and quantity of the topic, until making the theme topic hierarchical clustering algorithm to achieve the requirements; then it used hierarchical clustering algorithm to carry out a similar topic clustering, until that conditions met defaults.The simulation experiment results showed that the performance on recall and accuracy of the algorithm was better than the first two algorithms.
Aiming at the problem that micro-blog had large amount of information,the coalescing hierarchical clustering algorithm was not suitable and Single-Pass clustering algorithm results was not accurate, a new algorithm SP&HC integrating hierarchical clustering algorithm and Single-Pass clustering algorithm were put forward.It used Single-Pass clustering algorithm to make the large number of micro-blog text become into the simple clustering, in order to collect some small amplitude and high cohesive theme topic.This greatly streamlined the content and quantity of the topic, until making the theme topic hierarchical clustering algorithm to achieve the requirements; then it used hierarchical clustering algorithm to carry out a similar topic clustering, until that conditions met defaults.The simulation experiment results showed that the performance on recall and accuracy of the algorithm was better than the first two algorithms.
2014, 29(2)
:62-66.
doi: 10.3969/j.issn.2095-476X.2014.02.016
Abstract:
Aiming at the problem that the Shadowing model commonly used of received signal strength indicator(RSSI) ranging algorithm was limited due to the effect of environmental factors such as the terrain in practice,a RSSI ranging algorithm was proposed based on piecewise polynomial fitting.This method,using of least-squares fitting function,fitted the sampling of a finite number of RSSI data to a continuous piecewise cubic polynomial function,which could simulate more accurately RSSI attenuation under specific circumstances.Using this algorithm and simulation experiments to seek appropriate number of segments and split points, the results showed that the average error was decreased from 2.25 m to 0.877 8 m using two-piecewise fitting method.
Aiming at the problem that the Shadowing model commonly used of received signal strength indicator(RSSI) ranging algorithm was limited due to the effect of environmental factors such as the terrain in practice,a RSSI ranging algorithm was proposed based on piecewise polynomial fitting.This method,using of least-squares fitting function,fitted the sampling of a finite number of RSSI data to a continuous piecewise cubic polynomial function,which could simulate more accurately RSSI attenuation under specific circumstances.Using this algorithm and simulation experiments to seek appropriate number of segments and split points, the results showed that the average error was decreased from 2.25 m to 0.877 8 m using two-piecewise fitting method.
2014, 29(2)
:67-70.
doi: 10.3969/j.issn.2095-476X.2014.02.017
Abstract:
Aiming at the problem that one kind of threshold segmentation algorithms was difficult for different images for effective segmentation,a multi-threshold algorithm fusion method based on introducing several common threshold segmentation algorithms was presented.This method got a set of thresholds by different algorithms and got a combination of them by organic iterative manner,and defined a reward function to select the optimal threshold.The experiment results showed that this method could be used for different types of image to get optimal threshold value for effective segmentation,eliminate the barriers which the user must have prior knowledge and eliminate the trouble of manually selecting segmentation method.
Aiming at the problem that one kind of threshold segmentation algorithms was difficult for different images for effective segmentation,a multi-threshold algorithm fusion method based on introducing several common threshold segmentation algorithms was presented.This method got a set of thresholds by different algorithms and got a combination of them by organic iterative manner,and defined a reward function to select the optimal threshold.The experiment results showed that this method could be used for different types of image to get optimal threshold value for effective segmentation,eliminate the barriers which the user must have prior knowledge and eliminate the trouble of manually selecting segmentation method.
2014, 29(2)
:71-74.
doi: 10.3969/j.issn.2095-476X.2014.02.018
Abstract:
Aiming at the poor performance of agricultural intelligence development platform in open source,free charge and human-computer interaction based on Windows Mobile,under Android platform,a method of leaf image disease detection based on maximum between-cluster variance and Canny operator was proposed.Firstly,adaptive median filter was used to smooth leaf images.Secondly,the images were processed by grey scale transformation.Then,the transformed images were segmented to bi-value images by adopting a method based on maximum between-cluster variance.Finally,the bi-value images images were processed by edge detection based on Canny operator.Experimental result showed that this method achieved leaf image disease detection under Android platform.The method which could reduce marginal noise and extract the edge of leaf image disease effectively provided robustness,effectiveness and correctness.
Aiming at the poor performance of agricultural intelligence development platform in open source,free charge and human-computer interaction based on Windows Mobile,under Android platform,a method of leaf image disease detection based on maximum between-cluster variance and Canny operator was proposed.Firstly,adaptive median filter was used to smooth leaf images.Secondly,the images were processed by grey scale transformation.Then,the transformed images were segmented to bi-value images by adopting a method based on maximum between-cluster variance.Finally,the bi-value images images were processed by edge detection based on Canny operator.Experimental result showed that this method achieved leaf image disease detection under Android platform.The method which could reduce marginal noise and extract the edge of leaf image disease effectively provided robustness,effectiveness and correctness.
2014, 29(2)
:75-79.
doi: 10.3969/j.issn.2095-476X.2014.02.019
Abstract:
Aimed at the problem existed in the previous management system of young cadres,such as scattered data,no unified data rules and low level of information,a design scheme of statistical system based on the technology of data warehouse was proposed.The system used component-based development techniques and C/S architecture to build the system framework,and used MVC architectural pattern toa chieve the separation of presentation layer,control layer and the model layer.The level of information and the capability of multidimensional data analysis had been greatly improved by applying the concept of data warehouse.He'nan Province as an application exampleproved that the design of the system was reasonable and effective.
Aimed at the problem existed in the previous management system of young cadres,such as scattered data,no unified data rules and low level of information,a design scheme of statistical system based on the technology of data warehouse was proposed.The system used component-based development techniques and C/S architecture to build the system framework,and used MVC architectural pattern toa chieve the separation of presentation layer,control layer and the model layer.The level of information and the capability of multidimensional data analysis had been greatly improved by applying the concept of data warehouse.He'nan Province as an application exampleproved that the design of the system was reasonable and effective.
2014, 29(2)
:80-86.
doi: 10.3969/j.issn.2095-476X.2014.02.020
Abstract:
By adding the internal heat exchanger and bypass valve, the transcritical CO2 refrigeration sys- tem with dual throttle valve was improved. Through the theoretical analysis and calculation of system performance parameters, it was concluded that:There was an optimum high-pressure Ph,opt, the relationship between the optimum high-pressure (Ph,opt), the gas cooler outlet temperature (T3) and the evaporation temperature (Te) was:Ph,opt=0.264 3 T3-0.008 9 Te-70.255 4; there was a larger increase in the region lower than the optimum high-pressure when the internal heat exchanger was used,there was little impact on system performance when the bypass valve was used from a theoretical calculation view.
By adding the internal heat exchanger and bypass valve, the transcritical CO2 refrigeration sys- tem with dual throttle valve was improved. Through the theoretical analysis and calculation of system performance parameters, it was concluded that:There was an optimum high-pressure Ph,opt, the relationship between the optimum high-pressure (Ph,opt), the gas cooler outlet temperature (T3) and the evaporation temperature (Te) was:Ph,opt=0.264 3 T3-0.008 9 Te-70.255 4; there was a larger increase in the region lower than the optimum high-pressure when the internal heat exchanger was used,there was little impact on system performance when the bypass valve was used from a theoretical calculation view.
2014, 29(2)
:87-90,95.
doi: 10.3969/j.issn.2095-476X.2014.02.021
Abstract:
The effect of different tube row number on heat transfer and pressure drop characteristics of dimpled fin tube heat exchanger was investigated.The results showed that:the ratio of heat transfer rate and pressuer drop(Q/ΔP) and COP decreased with the increase of tube row number, Q/ΔP and COP of two-row tube was the biggest.Compared with the three, four, five-row tube, average Nu number of two-row tube increased by 11.1%, 21.7%, 23.2% at Re=1 138~3 415, respectively.The flow filed indicated that the arrangement of the dimple could intensify flow turbulence,which enhanced the heat transfer,but when the number of tube rows are 4 and 5, the temperature field changed little,which indicated that the heat transfer didn't change significantly when the number of tube rows increased.So the comprehensive performance of two row tube rows was better.
The effect of different tube row number on heat transfer and pressure drop characteristics of dimpled fin tube heat exchanger was investigated.The results showed that:the ratio of heat transfer rate and pressuer drop(Q/ΔP) and COP decreased with the increase of tube row number, Q/ΔP and COP of two-row tube was the biggest.Compared with the three, four, five-row tube, average Nu number of two-row tube increased by 11.1%, 21.7%, 23.2% at Re=1 138~3 415, respectively.The flow filed indicated that the arrangement of the dimple could intensify flow turbulence,which enhanced the heat transfer,but when the number of tube rows are 4 and 5, the temperature field changed little,which indicated that the heat transfer didn't change significantly when the number of tube rows increased.So the comprehensive performance of two row tube rows was better.
2014, 29(2)
:91-95.
doi: 10.3969/j.issn.2095-476X.2014.02.022
Abstract:
A dynamic mathematical model of the variable rope length cable 3D crane system of bridge crane was proposed based on Matlab.It in the process of building coordinate system,chose the goal control variables as the variable of the coordinate system,analysed the coordinates of the location and was based on Lagrange equations.The variable of model was not only linked with the variable of control,but the changing of grabbing buckets' place caused by crane system was considered.The simulation results showed that the dynamic mathematical model was simple and tracking quickly.
A dynamic mathematical model of the variable rope length cable 3D crane system of bridge crane was proposed based on Matlab.It in the process of building coordinate system,chose the goal control variables as the variable of the coordinate system,analysed the coordinates of the location and was based on Lagrange equations.The variable of model was not only linked with the variable of control,but the changing of grabbing buckets' place caused by crane system was considered.The simulation results showed that the dynamic mathematical model was simple and tracking quickly.
2014, 29(2)
:96-98,108.
doi: 10.3969/j.issn.2095-476X.2014.02.023
Abstract:
A finite element model simulating the experiment on X-type branch plate-to-square hollow section connection was generated by ABAQUS and validated by comparing the axial ultimate capacity,strain distribution and failure mode with experimental results.The result showed that under the effect of axial pressure,plate local buckled near the weld,the plate tilted because of out-of-plane instability;it should be avoided that due to the fact the thickness of plate was relatively smaller than chord joints should be strengthened by increasing plate thickness or installing rib stiffener on bath sides of plate in engineering; X-type branch plate-to-square hollow section connections had weak plastic deformation capacity from plasticity.
A finite element model simulating the experiment on X-type branch plate-to-square hollow section connection was generated by ABAQUS and validated by comparing the axial ultimate capacity,strain distribution and failure mode with experimental results.The result showed that under the effect of axial pressure,plate local buckled near the weld,the plate tilted because of out-of-plane instability;it should be avoided that due to the fact the thickness of plate was relatively smaller than chord joints should be strengthened by increasing plate thickness or installing rib stiffener on bath sides of plate in engineering; X-type branch plate-to-square hollow section connections had weak plastic deformation capacity from plasticity.
Computer simulation on dynamical buckling and whole collapse of cylindrical shell under axial impact
2014, 29(2)
:99-101.
doi: 10.3969/j.issn.2095-476X.2014.02.024
Abstract:
The computer simulation on dynamic buckling and whole collapse of cylindrical shell under different axial impact was carried out using LS-DYNA.The numerical results and the experimental results showed good agreement.The strains of the points which were located in the middle of the local buckling cylindrical shells were obtained.The strains showed that the local buckling cylindrical shells were in the plastic stage and generated elastic vibration subsequently until standstill.
The computer simulation on dynamic buckling and whole collapse of cylindrical shell under different axial impact was carried out using LS-DYNA.The numerical results and the experimental results showed good agreement.The strains of the points which were located in the middle of the local buckling cylindrical shells were obtained.The strains showed that the local buckling cylindrical shells were in the plastic stage and generated elastic vibration subsequently until standstill.
2014, 29(2)
:102-104.
doi: 10.3969/j.issn.2095-476X.2014.02.025
Abstract:
The problem of sliding mode variable structure control of Lurie complex network chaos systems was studied.Two drive-response dynamical modes of Lurie complex networks was founded.It was proved that Lurie chaotic systems was synchronized using sliding mode control synchronization approach based on Lyapunov stable theory.
The problem of sliding mode variable structure control of Lurie complex network chaos systems was studied.Two drive-response dynamical modes of Lurie complex networks was founded.It was proved that Lurie chaotic systems was synchronized using sliding mode control synchronization approach based on Lyapunov stable theory.
2014, 29(2)
:105-108.
doi: 10.3969/j.issn.2095-476X.2014.02.026
Abstract:
Aiming at the problem of fewer practical decision condition whether a matrix is nonsingular H-matrix, based on the properties of matrix element itself,by constructing positive diagonal matrix and comprehensive utilization of inequality techniques and sufficient and necessary conditions of nonsingular H-matrix,some of the judgement theorem were expanded and improved.And the scope of judging nonsingular matrices was also expanded.The numerical example showed that the new criterion had wide range of application than the original results.
Aiming at the problem of fewer practical decision condition whether a matrix is nonsingular H-matrix, based on the properties of matrix element itself,by constructing positive diagonal matrix and comprehensive utilization of inequality techniques and sufficient and necessary conditions of nonsingular H-matrix,some of the judgement theorem were expanded and improved.And the scope of judging nonsingular matrices was also expanded.The numerical example showed that the new criterion had wide range of application than the original results.
Journal Information
Founded in 1986， bimonthly
Administered by：The Education Department Henan Province
Sponsored by：Zhengzhou University of Light Industry
Editor-in-chief：Wei Shizhong
Executive Editor-in-Chief：Zou Lin
Subeditor：Qu Shuanghong
Edited & published by：Editorial Department of Journal of Light Industry
CN 41-1437/TS
ISSN 2096-1553
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