The mechanism of separating hematite from kaolinite by shear-flocculation and the reason responsible for the selectivity of shear-flocculation was studied by using diffuse reflectance infrared Fourier transform (DRIFT...The mechanism of separating hematite from kaolinite by shear-flocculation and the reason responsible for the selectivity of shear-flocculation was studied by using diffuse reflectance infrared Fourier transform (DRIFT) spec-troscopy, which was found to be effective for analysing adsorbed oleate species on the highly absorbing mineral hematite. The spectra suggest that chemisorption of oleate on hematite took place under shear-flocculation condition and that the chemisorbed species was bridged bidentate, corresponding to a peak at 1580 cm-1. Dimers of oleic acid, corresponding to a peak at 1710 cm-1, adsorbed via hydrocarbon chain association with the chemisorbed oleate. The coexistance of physically adsorbed oleic acid dimers and chemisorbed oleate ions made the surface of hematite hydrophobic, which would remain under the shear field. Under the same condition , the surface of kaolinite did not adsorb oleic acid or oleate and remained hydrophilic. The shear field of sufficient magnitude made the hydrophobic ultrafine particles of hematite to aggregate, whereas the hydrophilic ultrafine particles of kaolinite remained suspended in solution. This explains the mechanism of selective shear-flocculation of hematite from kaolinite.展开更多
With the insight of memristor researsh growing continuously,many semiconductor material has been manufactured to various kinds of memristive device.Yet the stabilization of memristive performance haven’t been fulfill...With the insight of memristor researsh growing continuously,many semiconductor material has been manufactured to various kinds of memristive device.Yet the stabilization of memristive performance haven’t been fulfilled,the fathom of memristive-acting mechanism still not being generalized.To put a futher move on low-consuming and high-stable memristive conductance device,we built a high stable double-pair-electrode device,based on the fabrication of TiO_(2-x),which has been generally applied as a n-type semiconductor.Under the constant-repeating cyclic voltammerty;we nailed the memristive quality of our mental/semiconductor thin film device.Moreover,through multifarious analytical processes based on our doping,filming growing path,we build a rational model for our memristor‘s memristive conductance mechanism,which indicated the carrier motion and electron tunnel following the biasing voltage.Our work exhibited a new type of TiO_(2-x)-based memristor,and emerged a new way to explicate the single-stage-switching memristive feature,which might initiate a new guiding ideology in semiconductor memristor’s studying.展开更多
Droplet drift wastes pesticide,pollutes the environment,and has become one of the focus issues of agricultural crop protection.Electrostatic spray technology reduces drift to a certain degree.In order to investigate t...Droplet drift wastes pesticide,pollutes the environment,and has become one of the focus issues of agricultural crop protection.Electrostatic spray technology reduces drift to a certain degree.In order to investigate the droplet drift pattern of a conical electrostatic nozzle,the droplet drift mass center distance was defined as an experimental index and used to conduct experimental wind tunnel studies on droplet drift.A mathematical model of the droplet drift mass center distance versus electrostatic voltage and wind speed was created via the regression method.The test results showed that the electrostatic voltage had an insignificant effect on droplet drift,the wind speed and its interaction with the electrostatic voltage had significant effects on droplet drift.When the wind speed was less than 3 m/s and stable,the crop adsorbability of a droplet had a dominant effect on the droplet drift;the droplet drift decreased with the increase of electrostatic voltage.When the wind speed exceeded 3 m/s and was stable,the reduced droplet particle size had a dominant effect on droplet drift,where droplet drift increased as the electrostatic voltage increased.When the wind speed was 0 m/s and the electrostatic voltage was 12 kV,the minimum droplet drift mass center distance was 35.5 mm,which was 56 mm less than that of conventional nozzle droplet drift.Therefore,a conical electrostatic nozzle is inapplicable for operation in an environment where wind speeds exceed 3 m/s.This study provides a reference for optimizing operational parameters of conical electrostatic nozzles and improving the anti-drift capability of droplets.展开更多
The interactions between NO, O2 and their mixture on BaAl2O4, as well as the reaction of NOx with soot in the presence of O2, have been investigated using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (D...The interactions between NO, O2 and their mixture on BaAl2O4, as well as the reaction of NOx with soot in the presence of O2, have been investigated using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). NO adsorption produces only nitrites species in the absence of O2. NO2 ad- sorption produces nitrates species besides nitrites species. The produced nitrites will further react with O2, O-su rf and O l2-att ice to form nitrates. The reaction of NOx with soot begins with the reaction of ni- trates with soot oxygenated complex (C(O)), which is regarded as the key and rate determining step. A reaction pathway is proposed for the catalyzed reaction of NOx with soot in the presence of O2.展开更多
文摘The mechanism of separating hematite from kaolinite by shear-flocculation and the reason responsible for the selectivity of shear-flocculation was studied by using diffuse reflectance infrared Fourier transform (DRIFT) spec-troscopy, which was found to be effective for analysing adsorbed oleate species on the highly absorbing mineral hematite. The spectra suggest that chemisorption of oleate on hematite took place under shear-flocculation condition and that the chemisorbed species was bridged bidentate, corresponding to a peak at 1580 cm-1. Dimers of oleic acid, corresponding to a peak at 1710 cm-1, adsorbed via hydrocarbon chain association with the chemisorbed oleate. The coexistance of physically adsorbed oleic acid dimers and chemisorbed oleate ions made the surface of hematite hydrophobic, which would remain under the shear field. Under the same condition , the surface of kaolinite did not adsorb oleic acid or oleate and remained hydrophilic. The shear field of sufficient magnitude made the hydrophobic ultrafine particles of hematite to aggregate, whereas the hydrophilic ultrafine particles of kaolinite remained suspended in solution. This explains the mechanism of selective shear-flocculation of hematite from kaolinite.
文摘With the insight of memristor researsh growing continuously,many semiconductor material has been manufactured to various kinds of memristive device.Yet the stabilization of memristive performance haven’t been fulfilled,the fathom of memristive-acting mechanism still not being generalized.To put a futher move on low-consuming and high-stable memristive conductance device,we built a high stable double-pair-electrode device,based on the fabrication of TiO_(2-x),which has been generally applied as a n-type semiconductor.Under the constant-repeating cyclic voltammerty;we nailed the memristive quality of our mental/semiconductor thin film device.Moreover,through multifarious analytical processes based on our doping,filming growing path,we build a rational model for our memristor‘s memristive conductance mechanism,which indicated the carrier motion and electron tunnel following the biasing voltage.Our work exhibited a new type of TiO_(2-x)-based memristor,and emerged a new way to explicate the single-stage-switching memristive feature,which might initiate a new guiding ideology in semiconductor memristor’s studying.
基金the National Key Technology R&D Program:Study and demonstration of technology and equipment for the entire cycle of large-scale production of high-quality rice(2014BAD06B01).
文摘Droplet drift wastes pesticide,pollutes the environment,and has become one of the focus issues of agricultural crop protection.Electrostatic spray technology reduces drift to a certain degree.In order to investigate the droplet drift pattern of a conical electrostatic nozzle,the droplet drift mass center distance was defined as an experimental index and used to conduct experimental wind tunnel studies on droplet drift.A mathematical model of the droplet drift mass center distance versus electrostatic voltage and wind speed was created via the regression method.The test results showed that the electrostatic voltage had an insignificant effect on droplet drift,the wind speed and its interaction with the electrostatic voltage had significant effects on droplet drift.When the wind speed was less than 3 m/s and stable,the crop adsorbability of a droplet had a dominant effect on the droplet drift;the droplet drift decreased with the increase of electrostatic voltage.When the wind speed exceeded 3 m/s and was stable,the reduced droplet particle size had a dominant effect on droplet drift,where droplet drift increased as the electrostatic voltage increased.When the wind speed was 0 m/s and the electrostatic voltage was 12 kV,the minimum droplet drift mass center distance was 35.5 mm,which was 56 mm less than that of conventional nozzle droplet drift.Therefore,a conical electrostatic nozzle is inapplicable for operation in an environment where wind speeds exceed 3 m/s.This study provides a reference for optimizing operational parameters of conical electrostatic nozzles and improving the anti-drift capability of droplets.
基金the National Natural Science Foundation of China (Grant No. 50506015) Shanghai Rising-Star Program (Grant No. 06QA14027)
文摘The interactions between NO, O2 and their mixture on BaAl2O4, as well as the reaction of NOx with soot in the presence of O2, have been investigated using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). NO adsorption produces only nitrites species in the absence of O2. NO2 ad- sorption produces nitrates species besides nitrites species. The produced nitrites will further react with O2, O-su rf and O l2-att ice to form nitrates. The reaction of NOx with soot begins with the reaction of ni- trates with soot oxygenated complex (C(O)), which is regarded as the key and rate determining step. A reaction pathway is proposed for the catalyzed reaction of NOx with soot in the presence of O2.
