By dynamic method under UV irradiation, commercial melt-blown polypropylene （PPMB） filter element was modified with acrylamide （AAm） using benzophenone （BP） as initiator. Attenuated total reflection-Fourier tran...By dynamic method under UV irradiation, commercial melt-blown polypropylene （PPMB） filter element was modified with acrylamide （AAm） using benzophenone （BP） as initiator. Attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscope verified that polyacrylamide chain was grafted on the fiber surface of PPMB filter element. Elemental content analysis with energy dispersive X-ray of fibers revealed that the polymerization content in the inner part of filter element was relatively higher than that in the outer. Degree of grafting changed with initiator concentration, monomer concentration, reaction temperature and reached 2.6% at the reaction condition： CBp=0.06 mol/L, CAAm=2.0 mol/L, irradiation time： 80 min, temperature： 60℃. Relative water flux altered with the hydrophilicity and pore size of filter element. In the antifouling test, the modified filter gave greater flux recovery （approximately 70%） after filtration of the water extract of Liuweidihuang, suggesting that the fouling layer was more easily reversible due to the hydrophilic nature of the modified filter.展开更多
Microfiltration is widely used in fine filtration operations, with dead-end filtration and cross-flow filtration. The microfiltration filter element or the microfiltration membrane is easy to be polluted by impurities...Microfiltration is widely used in fine filtration operations, with dead-end filtration and cross-flow filtration. The microfiltration filter element or the microfiltration membrane is easy to be polluted by impurities in the water and causes fouling, resulting in flux attenuation. The flux can be expressed by Darcy’s law and attenuation model. In this paper, two industrial titanium rod sintered filter elements (<span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>60 × 960 mm and <span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>60 × 960 mm) of different specifications are selected, and tap water (1.0 NTU) is used for constant pressure dead-end filtration. The amount tends to be the same, about 0.435 m<sup>3</sup><span style="white-space:nowrap;">·</span>m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span></span>2</sup><span style="white-space:nowrap;">·</span>h<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span></span>1</sup>, which has nothing to do with the filtration accuracy of the filter element but only depends on the characteristics of the filter cake and the filter membrane. Through the analysis of the two models, it is found that the two filtration flux models are not universal and difficult to be applied in engineering.展开更多
A method is proposed to improve the accuracy of remaining useful life prediction for rolling element bearings,based on a state space model(SSM)with different degradation stages and a particle filter.The model is impro...A method is proposed to improve the accuracy of remaining useful life prediction for rolling element bearings,based on a state space model(SSM)with different degradation stages and a particle filter.The model is improved by a method based on the Paris formula and the Foreman formula allowing the establishment of different degradation stages.The remaining useful life of rolling element bearings can be predicted by the adjusted model with inputs of physical data and operating status information.The late operating trend is predicted by the use of the particle filter algorithm.The rolling bearing full life experimental data validate the proposed method.Further,the prediction result is compared with the single SSM and the Gamma model,and the results indicate that the predicted accuracy of the proposed method is higher with better practicability.展开更多
With the wide use of color in many areas, the interest on the color perception and processing has been growing rapidly. An important topic in color image processing is the development of efficient tools capable of fil...With the wide use of color in many areas, the interest on the color perception and processing has been growing rapidly. An important topic in color image processing is the development of efficient tools capable of filtering images without blurring them and without changing their original chromatic contents. In this paper, a new technique reducing noise of color image is developed. A class of color-scale morphological operations is introduced, which extend mathematical morphology to color image processing, representing a color image as a vector function. The correlation between color components is utilized to perform noise removal. Color-scale morphological niters with multiple structuring elements (CSMF-MSEs) are proposed. Their properties are discussed and proved. Experimental results show that CSMF-MSEs are suitable and powerful to eliminate noise and preserve edges in color image because of efficient utilization of inherent correlation between color components, and they perform better than vector展开更多
The notion of e-filters is introduced in an MS-algebra and characterized. The concept of D-filters is introduced and a set of equivalent conditions under which every D-filter is an e-filter are given. The properties o...The notion of e-filters is introduced in an MS-algebra and characterized. The concept of D-filters is introduced and a set of equivalent conditions under which every D-filter is an e-filter are given. The properties of the space of all prime e-filters of an MS-algebra are observed. The concept of D-prime filters is introduced and then a set of equivalent conditions axe derived for a prime e-filter to become a D-prime filter in topological terms.展开更多
The implementation and characteristics of a compact lumped-element three-order low pass filter are presented in this paper. The filter with 120 MHz cut off frequency, as well as more than 20 dB of the attenuation abov...The implementation and characteristics of a compact lumped-element three-order low pass filter are presented in this paper. The filter with 120 MHz cut off frequency, as well as more than 20 dB of the attenuation above 360 MHz frequency band is successfully manufactured in an LTCC substrate with 40 pm layer thickness. The overall size of the filter is 2.0 mm×1.2 mm×0.9 mm. A good coincidence between the measured results and the full-wave electromagnetic designed responses is observed.展开更多
The effectiveness of deep-bed filtration with respect to suspension formed during the preceding processes is evaluated by the test of filterability. The properties and concentration of the suspension being filtered ar...The effectiveness of deep-bed filtration with respect to suspension formed during the preceding processes is evaluated by the test of filterability. The properties and concentration of the suspension being filtered are affected by the efficiency of the preceding aggregation and separation processes. The basic principles of the test of filterability are based on the mechanistic model of filtration. The equations in the mathematical model of the mechanistic conception of filtration are derived from the theory of filtration. The arrangement of the pilot filtration plant for the determination of filterability of flocculent suspension is presented in this paper. The test of filterability is carried out with a thin-layer filter element. The design of a filter element arrangement and its installation are also disclosed in this paper. The inter-dependence of the coefficient of filtration efficiency on the specific volume of intercepted suspensions, filter media grain sizes and different filtration velocities are graphically presented. In addition, the effect of the filter bed clogging resulting from the properties of different suspensions on the head loss generated, the length of filtration cycle and quality of filtrate produced are also shown in this paper.展开更多
Several approaches to fabricate micro optical elements by use of half tone masks are studied and compared. It is shown that half tone masks employed in filtering image systems can obtain gray patterns with considerabl...Several approaches to fabricate micro optical elements by use of half tone masks are studied and compared. It is shown that half tone masks employed in filtering image systems can obtain gray patterns with considerably high precision, but it is hard to operate from the viewpoint of operation. The method using contacting lithography technology or laser ablation can be easily operated with the cost of reducing fabrication precision and the trouble of choosing appropriate materials. For all of these methods, the coding of half tone masks with corrections for the nonlinear characteristics of coding, imaging and photoresist is recommended.展开更多
基金Project supported by the Natural Science Foundation of Beijing(No.2051002)Science and Technology Programme of Beijing(No.D0205004040421)
文摘By dynamic method under UV irradiation, commercial melt-blown polypropylene （PPMB） filter element was modified with acrylamide （AAm） using benzophenone （BP） as initiator. Attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscope verified that polyacrylamide chain was grafted on the fiber surface of PPMB filter element. Elemental content analysis with energy dispersive X-ray of fibers revealed that the polymerization content in the inner part of filter element was relatively higher than that in the outer. Degree of grafting changed with initiator concentration, monomer concentration, reaction temperature and reached 2.6% at the reaction condition： CBp=0.06 mol/L, CAAm=2.0 mol/L, irradiation time： 80 min, temperature： 60℃. Relative water flux altered with the hydrophilicity and pore size of filter element. In the antifouling test, the modified filter gave greater flux recovery （approximately 70%） after filtration of the water extract of Liuweidihuang, suggesting that the fouling layer was more easily reversible due to the hydrophilic nature of the modified filter.
文摘Microfiltration is widely used in fine filtration operations, with dead-end filtration and cross-flow filtration. The microfiltration filter element or the microfiltration membrane is easy to be polluted by impurities in the water and causes fouling, resulting in flux attenuation. The flux can be expressed by Darcy’s law and attenuation model. In this paper, two industrial titanium rod sintered filter elements (<span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>60 × 960 mm and <span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span>60 × 960 mm) of different specifications are selected, and tap water (1.0 NTU) is used for constant pressure dead-end filtration. The amount tends to be the same, about 0.435 m<sup>3</sup><span style="white-space:nowrap;">·</span>m<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span></span>2</sup><span style="white-space:nowrap;">·</span>h<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;"><span style="white-space:nowrap;">?</span></span></span>1</sup>, which has nothing to do with the filtration accuracy of the filter element but only depends on the characteristics of the filter cake and the filter membrane. Through the analysis of the two models, it is found that the two filtration flux models are not universal and difficult to be applied in engineering.
文摘A method is proposed to improve the accuracy of remaining useful life prediction for rolling element bearings,based on a state space model(SSM)with different degradation stages and a particle filter.The model is improved by a method based on the Paris formula and the Foreman formula allowing the establishment of different degradation stages.The remaining useful life of rolling element bearings can be predicted by the adjusted model with inputs of physical data and operating status information.The late operating trend is predicted by the use of the particle filter algorithm.The rolling bearing full life experimental data validate the proposed method.Further,the prediction result is compared with the single SSM and the Gamma model,and the results indicate that the predicted accuracy of the proposed method is higher with better practicability.
基金Supported by the Natural Science Foundation of China,No.69775004
文摘With the wide use of color in many areas, the interest on the color perception and processing has been growing rapidly. An important topic in color image processing is the development of efficient tools capable of filtering images without blurring them and without changing their original chromatic contents. In this paper, a new technique reducing noise of color image is developed. A class of color-scale morphological operations is introduced, which extend mathematical morphology to color image processing, representing a color image as a vector function. The correlation between color components is utilized to perform noise removal. Color-scale morphological niters with multiple structuring elements (CSMF-MSEs) are proposed. Their properties are discussed and proved. Experimental results show that CSMF-MSEs are suitable and powerful to eliminate noise and preserve edges in color image because of efficient utilization of inherent correlation between color components, and they perform better than vector
文摘The notion of e-filters is introduced in an MS-algebra and characterized. The concept of D-filters is introduced and a set of equivalent conditions under which every D-filter is an e-filter are given. The properties of the space of all prime e-filters of an MS-algebra are observed. The concept of D-prime filters is introduced and then a set of equivalent conditions axe derived for a prime e-filter to become a D-prime filter in topological terms.
基金This work was supported by the National Nature Science Foundation of China under Grant No. 60425102.
文摘The implementation and characteristics of a compact lumped-element three-order low pass filter are presented in this paper. The filter with 120 MHz cut off frequency, as well as more than 20 dB of the attenuation above 360 MHz frequency band is successfully manufactured in an LTCC substrate with 40 pm layer thickness. The overall size of the filter is 2.0 mm×1.2 mm×0.9 mm. A good coincidence between the measured results and the full-wave electromagnetic designed responses is observed.
文摘The effectiveness of deep-bed filtration with respect to suspension formed during the preceding processes is evaluated by the test of filterability. The properties and concentration of the suspension being filtered are affected by the efficiency of the preceding aggregation and separation processes. The basic principles of the test of filterability are based on the mechanistic model of filtration. The equations in the mathematical model of the mechanistic conception of filtration are derived from the theory of filtration. The arrangement of the pilot filtration plant for the determination of filterability of flocculent suspension is presented in this paper. The test of filterability is carried out with a thin-layer filter element. The design of a filter element arrangement and its installation are also disclosed in this paper. The inter-dependence of the coefficient of filtration efficiency on the specific volume of intercepted suspensions, filter media grain sizes and different filtration velocities are graphically presented. In addition, the effect of the filter bed clogging resulting from the properties of different suspensions on the head loss generated, the length of filtration cycle and quality of filtrate produced are also shown in this paper.
基金supported by 973 Program of China under Grant No.2006CB302900part by the National Natural Science Foundation of China under Grant No.60825405 and No.60778018
文摘Several approaches to fabricate micro optical elements by use of half tone masks are studied and compared. It is shown that half tone masks employed in filtering image systems can obtain gray patterns with considerably high precision, but it is hard to operate from the viewpoint of operation. The method using contacting lithography technology or laser ablation can be easily operated with the cost of reducing fabrication precision and the trouble of choosing appropriate materials. For all of these methods, the coding of half tone masks with corrections for the nonlinear characteristics of coding, imaging and photoresist is recommended.
