To solve the kinetic and diffusion problem of surface-type infrared decoy, multi-chaff kinetic models are established and chaff cloud holistic kinetic performance are analyzed under the impact of high speed airflow in...To solve the kinetic and diffusion problem of surface-type infrared decoy, multi-chaff kinetic models are established and chaff cloud holistic kinetic performance are analyzed under the impact of high speed airflow in this work. Chaffs rotate rapidly during the motion under the impact of high speed airflow. The rotation speed is correlated with lift, position of pressure center and aerodynamic damping. Computational Fluid Dynamics(CFD) is used to compute the aerodynamic coefficients of chaff. It is found that there exists serious aerodynamic interference which mainly relates to the overlapping area and distance among chaffs during the diffusion of chaff cloud. The chaff wind tunnel test and rocket sled experiment are carried out to verify the credibility of the models in this work. Then, the variation of chaff cloud expectation and extremum are analyzed to achieve the holistic kinetic and diffusing performance of chaff cloud. Simulation results demonstrate that the chaffs diffuse rapidly under the impact of high speed airflow and chaff cloud can be formed rapidly within 0.5 s. The shape of the chaff cloud is similar to cone that forms a certain angle with the horizontal plane and most chaffs focus on the second half.展开更多
Aimed at the difficulty in finding an efficient method to depress and recognize chaff in both time and frequency domain,this paper tries to recognize chaff and target such as warship in polarization domain under the t...Aimed at the difficulty in finding an efficient method to depress and recognize chaff in both time and frequency domain,this paper tries to recognize chaff and target such as warship in polarization domain under the theoretical analysis of the polarization scattering cross section of chaff.In order to find target more exactly,non-linear polarization transformation and polarization smoothness are applied to process the polarization information of chaff and ship target.The resulting recognition is proved to be effective by simulation.展开更多
To calculate the diffusion law of chaff cloud launched by aircraft,taking rectangular chaff as an example,the diffusion model of chaff cloud is established in this paper.Firstly,the coordinate systems of chaff are def...To calculate the diffusion law of chaff cloud launched by aircraft,taking rectangular chaff as an example,the diffusion model of chaff cloud is established in this paper.Firstly,the coordinate systems of chaff are defined and the motion model of chaff is established.The motion model mainly includes chaff motion equation and rotation equation,which are obtained by combining the aerodynamic moment and aerodynamic damping.Then,the influence of multi-chaff aerodynamic interference on the movement of chaff is analyzed.Finally,considering the influence of overlap area between chaffs and chaff spacing on the aerodynamic coefficients,the multi-chaff motion model is obtained,and the simulation results are compared with the test results to verify the credibility of the model.展开更多
The adsorption ofEscherichia coli and Staphylococcus aureus on chaff and WMDP （waste of molasses dates production） has been studied. FTIR spectra were employed to investigate the adsorption ofEscherichia coli and St...The adsorption ofEscherichia coli and Staphylococcus aureus on chaff and WMDP （waste of molasses dates production） has been studied. FTIR spectra were employed to investigate the adsorption ofEscherichia coli and Staphylococcus aureus on surfaces. Adsorption of bacteria resulted in obvious shifts of some infrared bands of adsorbents. The adsorption isotherms ofEscherichia coli on two surfaces and Staphylococcus aureus on WMDP, are of L-curve type according to Giles classification. However, type H isotherm was observed in the adsorption of S. aureus on chaff. The adsorption isotherms of bacteria on the examined adsorbents conformed to the Langmuir and Temkin equations. The adsorption of bacteria was studied at different temperatures （10, 25 and 40 ℃）, the thermodynamic parameters （AH, AS and AG） have also been calculated and it has been found that the adsorption process of bacteria was exothermic in nature. The number of bacteria adsorbed on surfaces was decreased with the increase of sodium chloride concentration. The amount of bacteria cells adsorbed was increased in the presence of different cations and followed the sequence： FeCl3 〉 CaCl2 〉 KCl 〉 NaCl. The pseudo-first order and pseudo-second order models for describing the kinetic data were applied and it was found that the process was well described by pseudo-second order model. The desorption studies indicated that the bacteria were strongly retained by two adsorbents.展开更多
A mesophilic-dry anaerobic digestion process is valid in treating high-concentration substrates containing low moisture content. It has merits of lower wastewater discharge and lower heat capacity required in maintain...A mesophilic-dry anaerobic digestion process is valid in treating high-concentration substrates containing low moisture content. It has merits of lower wastewater discharge and lower heat capacity required in maintaining reactor temperature as compared with a thermophilic-wet anaerobic digestion process. In fact, chaff can be easily obtained in farming areas and used as a mixture substrate as one of bulking agents for controlling moisture and supplying carbon. For this reason, this study applies the chaff to improve livestock manure, which contains high moisture content and is discharged from domestic pig farms. This study aims at verifying its feasibility for improving methane production efficiency on a basis of BMP (Biochemical Methane Potential) assay obtained through a series of experiments. Finding results were methane gas production and gas production per volatile solid (VS) added, and methane gas production among biogas production were increased as the chaff added in the piggery manure was increased. According to experimental results for improving the methane production efficiency, mixture of the chaff and the piggery manure played an important role in controlling the moisture content and improving the methane gas production rate, and also verified its feasibility in the mesophilic-dry anaerobic digestion process indicating relatively less difficulty for operation and management.展开更多
A modified chaff jamming recognition method of radar is investigated using grey relational analysis（ GRA） based on the difference in echo correlation characteristics between a complex rigid target and chaff cloud in...A modified chaff jamming recognition method of radar is investigated using grey relational analysis（ GRA） based on the difference in echo correlation characteristics between a complex rigid target and chaff cloud in time domain. Slice method（ SM）,a novel modeling approach,is proposed to construct an electromagnetic scattering model of chaff cloud in a scenario with slowly moving platform that is targeted. The diffusion characteristics and echo characteristics of the chaff cloud are analyzed. The GRA of a real target and chaff cloud shows that the adjacent return waves have a good correlation for the target but a weak correlation for chaff cloud. Since the correlation degree of chaff cloud＇s echo is far lower than that of a complex rigid target＇s,the chaff jamming can be identified by setting a reasonable threshold. Simulation results are presented to verify the effectiveness of this method.展开更多
As the chaff centroid jamming can introduce the guiding error of the anti-warship missile's seeker and decrease its hitting probability,a new quantitative analysis method and a mathematic model are proposed in thi...As the chaff centroid jamming can introduce the guiding error of the anti-warship missile's seeker and decrease its hitting probability,a new quantitative analysis method and a mathematic model are proposed in this paper to evaluate the success jamming probability.By using this method,the optimal decision scheme of chaff centroid jamming in different threat situations can be found,and also the success probability of this scheme can be calculated quantitatively.Thus,the operation rules of the centroid jamming and the tactical approach for increasing the success probability can be determined.展开更多
建立红芪生品及不同炮制品(药典法炙红芪、蜜糠炙红芪)的HPLC指纹图谱及多成分含量测定方法,综合评价红芪及其不同炮制品质量。采用HPLC法建立红芪不同炮制品指纹图谱并对5种主要成分进行含量测定,通过主成分分析(principal component a...建立红芪生品及不同炮制品(药典法炙红芪、蜜糠炙红芪)的HPLC指纹图谱及多成分含量测定方法,综合评价红芪及其不同炮制品质量。采用HPLC法建立红芪不同炮制品指纹图谱并对5种主要成分进行含量测定,通过主成分分析(principal component analysis,PCA)、正交偏最小二乘-判别分析(orthogonal partial least squares-discrimination analysis,OPLS-DA)等方法对结果进行分析,并结合灰色关联度分析理论计算指标权重值,建立加权-逼近理想解排序法(technique for order preference by similarity to ideal solution,TOPSIS)算法模型,对红芪及其不同炮制品进行质量评价。结果表明,红芪不同炮制品指纹图谱中有22个共有峰,指认出5个共有峰,分别为香草酸(峰5)、毛蕊异黄酮苷(峰8)、芒柄花苷(峰12)、毛蕊异黄酮(峰17)、芒柄花素(峰18);PCA共提取出5个主成分,综合评分中15批次蜜糠炙红芪排名靠前;加权TOPSIS模型结果表明红芪不同炮制品各15批次的相对接近度值分别为生红芪0.1161~0.4473,炙红芪0.2383~0.5011,蜜糠炙红芪0.3189~0.6542。本研究建立的HPLC指纹图谱及多成分含量测定方法操作简便,稳定可靠,加权TOPSIS算法模型合理,可用于红芪及其不同炮制品的综合质量评价。展开更多
基金supported by the National Natural Science Foundation of China (No. 61471390)
文摘To solve the kinetic and diffusion problem of surface-type infrared decoy, multi-chaff kinetic models are established and chaff cloud holistic kinetic performance are analyzed under the impact of high speed airflow in this work. Chaffs rotate rapidly during the motion under the impact of high speed airflow. The rotation speed is correlated with lift, position of pressure center and aerodynamic damping. Computational Fluid Dynamics(CFD) is used to compute the aerodynamic coefficients of chaff. It is found that there exists serious aerodynamic interference which mainly relates to the overlapping area and distance among chaffs during the diffusion of chaff cloud. The chaff wind tunnel test and rocket sled experiment are carried out to verify the credibility of the models in this work. Then, the variation of chaff cloud expectation and extremum are analyzed to achieve the holistic kinetic and diffusing performance of chaff cloud. Simulation results demonstrate that the chaffs diffuse rapidly under the impact of high speed airflow and chaff cloud can be formed rapidly within 0.5 s. The shape of the chaff cloud is similar to cone that forms a certain angle with the horizontal plane and most chaffs focus on the second half.
文摘Aimed at the difficulty in finding an efficient method to depress and recognize chaff in both time and frequency domain,this paper tries to recognize chaff and target such as warship in polarization domain under the theoretical analysis of the polarization scattering cross section of chaff.In order to find target more exactly,non-linear polarization transformation and polarization smoothness are applied to process the polarization information of chaff and ship target.The resulting recognition is proved to be effective by simulation.
基金This work is supported by the National Natural Science Foundation of China(grant number 61471390).
文摘To calculate the diffusion law of chaff cloud launched by aircraft,taking rectangular chaff as an example,the diffusion model of chaff cloud is established in this paper.Firstly,the coordinate systems of chaff are defined and the motion model of chaff is established.The motion model mainly includes chaff motion equation and rotation equation,which are obtained by combining the aerodynamic moment and aerodynamic damping.Then,the influence of multi-chaff aerodynamic interference on the movement of chaff is analyzed.Finally,considering the influence of overlap area between chaffs and chaff spacing on the aerodynamic coefficients,the multi-chaff motion model is obtained,and the simulation results are compared with the test results to verify the credibility of the model.
文摘The adsorption ofEscherichia coli and Staphylococcus aureus on chaff and WMDP （waste of molasses dates production） has been studied. FTIR spectra were employed to investigate the adsorption ofEscherichia coli and Staphylococcus aureus on surfaces. Adsorption of bacteria resulted in obvious shifts of some infrared bands of adsorbents. The adsorption isotherms ofEscherichia coli on two surfaces and Staphylococcus aureus on WMDP, are of L-curve type according to Giles classification. However, type H isotherm was observed in the adsorption of S. aureus on chaff. The adsorption isotherms of bacteria on the examined adsorbents conformed to the Langmuir and Temkin equations. The adsorption of bacteria was studied at different temperatures （10, 25 and 40 ℃）, the thermodynamic parameters （AH, AS and AG） have also been calculated and it has been found that the adsorption process of bacteria was exothermic in nature. The number of bacteria adsorbed on surfaces was decreased with the increase of sodium chloride concentration. The amount of bacteria cells adsorbed was increased in the presence of different cations and followed the sequence： FeCl3 〉 CaCl2 〉 KCl 〉 NaCl. The pseudo-first order and pseudo-second order models for describing the kinetic data were applied and it was found that the process was well described by pseudo-second order model. The desorption studies indicated that the bacteria were strongly retained by two adsorbents.
文摘A mesophilic-dry anaerobic digestion process is valid in treating high-concentration substrates containing low moisture content. It has merits of lower wastewater discharge and lower heat capacity required in maintaining reactor temperature as compared with a thermophilic-wet anaerobic digestion process. In fact, chaff can be easily obtained in farming areas and used as a mixture substrate as one of bulking agents for controlling moisture and supplying carbon. For this reason, this study applies the chaff to improve livestock manure, which contains high moisture content and is discharged from domestic pig farms. This study aims at verifying its feasibility for improving methane production efficiency on a basis of BMP (Biochemical Methane Potential) assay obtained through a series of experiments. Finding results were methane gas production and gas production per volatile solid (VS) added, and methane gas production among biogas production were increased as the chaff added in the piggery manure was increased. According to experimental results for improving the methane production efficiency, mixture of the chaff and the piggery manure played an important role in controlling the moisture content and improving the methane gas production rate, and also verified its feasibility in the mesophilic-dry anaerobic digestion process indicating relatively less difficulty for operation and management.
基金Supported by the National Natural Science Foundation of China(61571043)111 Project of China(B14010)
文摘A modified chaff jamming recognition method of radar is investigated using grey relational analysis（ GRA） based on the difference in echo correlation characteristics between a complex rigid target and chaff cloud in time domain. Slice method（ SM）,a novel modeling approach,is proposed to construct an electromagnetic scattering model of chaff cloud in a scenario with slowly moving platform that is targeted. The diffusion characteristics and echo characteristics of the chaff cloud are analyzed. The GRA of a real target and chaff cloud shows that the adjacent return waves have a good correlation for the target but a weak correlation for chaff cloud. Since the correlation degree of chaff cloud＇s echo is far lower than that of a complex rigid target＇s,the chaff jamming can be identified by setting a reasonable threshold. Simulation results are presented to verify the effectiveness of this method.
文摘As the chaff centroid jamming can introduce the guiding error of the anti-warship missile's seeker and decrease its hitting probability,a new quantitative analysis method and a mathematic model are proposed in this paper to evaluate the success jamming probability.By using this method,the optimal decision scheme of chaff centroid jamming in different threat situations can be found,and also the success probability of this scheme can be calculated quantitatively.Thus,the operation rules of the centroid jamming and the tactical approach for increasing the success probability can be determined.
文摘建立红芪生品及不同炮制品(药典法炙红芪、蜜糠炙红芪)的HPLC指纹图谱及多成分含量测定方法,综合评价红芪及其不同炮制品质量。采用HPLC法建立红芪不同炮制品指纹图谱并对5种主要成分进行含量测定,通过主成分分析(principal component analysis,PCA)、正交偏最小二乘-判别分析(orthogonal partial least squares-discrimination analysis,OPLS-DA)等方法对结果进行分析,并结合灰色关联度分析理论计算指标权重值,建立加权-逼近理想解排序法(technique for order preference by similarity to ideal solution,TOPSIS)算法模型,对红芪及其不同炮制品进行质量评价。结果表明,红芪不同炮制品指纹图谱中有22个共有峰,指认出5个共有峰,分别为香草酸(峰5)、毛蕊异黄酮苷(峰8)、芒柄花苷(峰12)、毛蕊异黄酮(峰17)、芒柄花素(峰18);PCA共提取出5个主成分,综合评分中15批次蜜糠炙红芪排名靠前;加权TOPSIS模型结果表明红芪不同炮制品各15批次的相对接近度值分别为生红芪0.1161~0.4473,炙红芪0.2383~0.5011,蜜糠炙红芪0.3189~0.6542。本研究建立的HPLC指纹图谱及多成分含量测定方法操作简便,稳定可靠,加权TOPSIS算法模型合理,可用于红芪及其不同炮制品的综合质量评价。
