The electrochemical behavior of metallic passive film on rebar in concrete is characterized by its semiconductive nature. The charge distribution at the interface between a semiconductor and an electrolyte is often de...The electrochemical behavior of metallic passive film on rebar in concrete is characterized by its semiconductive nature. The charge distribution at the interface between a semiconductor and an electrolyte is often determined by measuring the capacitance of the space-charge layer （Csc） as a function of the electrode potential （E）. When the space charge-layer serves as the depletion layer, the relation of Csc^-2 vs E resembles a Mott-Schottky plot （M-S plot）. The semiconductive properties of the passive film on rebar in concrete were analyzed with M-S plots to study the effect of chloride ions and mineral admixtures on rebar passive films. Some rebar electrodes were immersed in simulated concrete pore solutions, while others were embedded in concrete with/without mineral admixtures. In saturated Ca（OH）, solutions, the relation of Csc^-2-E of rebar electrodes shows linear MottSchottky relationship indicating that the passive film on rebar is a highly disordered n-type semiconductor, with donor density （ND） in the order of 10^26m^-3. After adding chloride ions （Cl wt%〈0.2%） in system solutions, the M-S plot slopes significantly decreased and ND increased, suggesting that chloride ion will cause passive film corrosion and breakdown. The M-S plots of the passive film on rebar electrodes embedded in concrete were similar to those immersed in simulated system solution. However, ND of those in concrete with mineral admixtures tended to be a little smaller, indicating that introducing proper quantity admixtures into concrete could make the rebar passive film have a thicker space-charge layer and therefore a thicker passive film layer.展开更多
Background Coronary artery fistula （CAF） is a rare anomaly.Transcatheter CAF closure has been introduced using various materials,but only few data are available on the Guglielmi detachable coil （GDC）.The advantage...Background Coronary artery fistula （CAF） is a rare anomaly.Transcatheter CAF closure has been introduced using various materials,but only few data are available on the Guglielmi detachable coil （GDC）.The advantage of using GDC for transcatheter CAF closure is more controllable,therefore much safer when compared to other coils.This report is about our experience in transcatheter closure of CAF using fibered GDC in our hospital.Methods ＆ Results From 2002 to 2007,there were 10 patients with CAFs （age range：28 to 56 year-old,7 males） who underwent transcatheter CAF closure.There were a total of 19 CAFs which originated from right coronary （n =5）,left circumflex （n =3）,left anterior descending artery （n =10） and left main trunk （n =1）.Median number of coil deployment for each fistula was 3 （range：1 to 6）.The pulmonary artery was the most common site of the distal communication of CAFs （n =14）,followed by right atrium （n =3）,left atrium （n =1） and left ventricle （n =1）.Immediate coronary angiography after GDC deployment revealed no residual shunt in 12 （63.2％） CAFs,significant reduction of the flow in 5 （26.3％）,while 2 （10.5％） could not be closed due to small size.Nine （90％） patients underwent a repeated angiography within 3 to 8 months.Among 12 CAFs that were occluded immediately post-deployment,there were 2 CAFs with insignificant residual flow.Among 6 CAFs with significantly decreased flow immediately post-deployment,2 were occluded totally in the follow-up angiography.In total,12 （70.5％） CAFs were occluded completely and 5 （29.5％） CAFs still had insignificant residual flow,which did not need any additional coil deployment.During a mean follow up of 4.3 ± 0.7 year,all patients remained symptom and complication free.Conclusions The fibered GDC is a safe and effective method for percutaneous closure of the CAFs.展开更多
Electrically conductive composite films ofpolyaniline and nylon-6.6 are prepared by diffusing aniline followed by oxidative polymerization of aniline into nylon-6.6 matrix. In order to determine the diffusion coeffici...Electrically conductive composite films ofpolyaniline and nylon-6.6 are prepared by diffusing aniline followed by oxidative polymerization of aniline into nylon-6.6 matrix. In order to determine the diffusion coefficient for the chloride ion diffusion into the composite matrix electrochemically, galvanostatic pulse method is used and the diffusion coefficient is estimated to be -6.48× 10^-17 cm^2s^-1. The results are discussed in view of them being potential replacement materials for battery. electrodes and sensors devices.展开更多
A novel high step-down non-isolated DC-DC converter has been proposed. The proposed converter consists of highly efficient non-isolated cell converters using bidirectional semiconductor power devices, and these cell c...A novel high step-down non-isolated DC-DC converter has been proposed. The proposed converter consists of highly efficient non-isolated cell converters using bidirectional semiconductor power devices, and these cell converters are connected in ISOP （input series and output parallel）. The non-isolated ISOP converter achieves high step-down ratio of D/N, operating N cell converters under the duty ratio olD. Availability of the proposed converter has been shown by developing the 48 V-12 V laboratory prototype using two 24 V-12 V cell converters. Design consideration for the 48 V-3 V multicellular converter using four 12 V-3 V cell converters has been also conducted, and the potential to approach the efficiency of 97% has been discussed. The proposed topology is suitable for the POL （point of load） converters in the highly efficient next generation DC distribution system for data centers.展开更多
We consider the problem of the two-point resistance on an m ×n cobweb network with a 2r boundary, which has never been solved before. Up to now researchers just only solved the cases with free boundary or null re...We consider the problem of the two-point resistance on an m ×n cobweb network with a 2r boundary, which has never been solved before. Up to now researchers just only solved the cases with free boundary or null resistor boundary. This paper gives the general formulae of the resistance between any two nodes in both tinite and infinite cases using a method of direct summation pioneered by Tan [Z. Z. Tan, et al., J. Phys. A 46 （2013） 195202], which is simpler and can be easier to use in practice. This method contrasts the Green＇s function technique and the Laplacian matrix approach, which is difllcult to apply to the geometry of a cobweb with a 2r boundary. We deduce several interesting results according to our genera/formula. In the end we compare and illuminate our formulae with two examples. Our analysis gives the result directly as a single summation, and the result is mainly composed of the characteristic roots.展开更多
With the large latent heat and low cost, the paraffin has been widely used in battery thermal management(BTM) system to improve the efficiency and cycling life of power battery. The numerical model of paraffin melting...With the large latent heat and low cost, the paraffin has been widely used in battery thermal management(BTM) system to improve the efficiency and cycling life of power battery. The numerical model of paraffin melting in a cavity has been established, and the effects on the solid–liquid phase change process have been investigated for the purpose of enhancing the heat transfer performance of paraffin-based BTM system. The results showed that the location of the heating wall had great effects on the melting process. The paraffin in the cavity melted most quickly when the heating wall located at the bottom. Furthermore, the effects of thermal conductivity and the velocity of the slip wall have been considered. The gradient of liquid fraction increased with the increase in thermal conductivity, and the melting process could be accelerated or delayed by the slip wall with different velocity.展开更多
基金Project (No. 502019) supported by the Natural Science Foundationof Zhejiang Province, China
文摘The electrochemical behavior of metallic passive film on rebar in concrete is characterized by its semiconductive nature. The charge distribution at the interface between a semiconductor and an electrolyte is often determined by measuring the capacitance of the space-charge layer （Csc） as a function of the electrode potential （E）. When the space charge-layer serves as the depletion layer, the relation of Csc^-2 vs E resembles a Mott-Schottky plot （M-S plot）. The semiconductive properties of the passive film on rebar in concrete were analyzed with M-S plots to study the effect of chloride ions and mineral admixtures on rebar passive films. Some rebar electrodes were immersed in simulated concrete pore solutions, while others were embedded in concrete with/without mineral admixtures. In saturated Ca（OH）, solutions, the relation of Csc^-2-E of rebar electrodes shows linear MottSchottky relationship indicating that the passive film on rebar is a highly disordered n-type semiconductor, with donor density （ND） in the order of 10^26m^-3. After adding chloride ions （Cl wt%〈0.2%） in system solutions, the M-S plot slopes significantly decreased and ND increased, suggesting that chloride ion will cause passive film corrosion and breakdown. The M-S plots of the passive film on rebar electrodes embedded in concrete were similar to those immersed in simulated system solution. However, ND of those in concrete with mineral admixtures tended to be a little smaller, indicating that introducing proper quantity admixtures into concrete could make the rebar passive film have a thicker space-charge layer and therefore a thicker passive film layer.
文摘Background Coronary artery fistula （CAF） is a rare anomaly.Transcatheter CAF closure has been introduced using various materials,but only few data are available on the Guglielmi detachable coil （GDC）.The advantage of using GDC for transcatheter CAF closure is more controllable,therefore much safer when compared to other coils.This report is about our experience in transcatheter closure of CAF using fibered GDC in our hospital.Methods ＆ Results From 2002 to 2007,there were 10 patients with CAFs （age range：28 to 56 year-old,7 males） who underwent transcatheter CAF closure.There were a total of 19 CAFs which originated from right coronary （n =5）,left circumflex （n =3）,left anterior descending artery （n =10） and left main trunk （n =1）.Median number of coil deployment for each fistula was 3 （range：1 to 6）.The pulmonary artery was the most common site of the distal communication of CAFs （n =14）,followed by right atrium （n =3）,left atrium （n =1） and left ventricle （n =1）.Immediate coronary angiography after GDC deployment revealed no residual shunt in 12 （63.2％） CAFs,significant reduction of the flow in 5 （26.3％）,while 2 （10.5％） could not be closed due to small size.Nine （90％） patients underwent a repeated angiography within 3 to 8 months.Among 12 CAFs that were occluded immediately post-deployment,there were 2 CAFs with insignificant residual flow.Among 6 CAFs with significantly decreased flow immediately post-deployment,2 were occluded totally in the follow-up angiography.In total,12 （70.5％） CAFs were occluded completely and 5 （29.5％） CAFs still had insignificant residual flow,which did not need any additional coil deployment.During a mean follow up of 4.3 ± 0.7 year,all patients remained symptom and complication free.Conclusions The fibered GDC is a safe and effective method for percutaneous closure of the CAFs.
文摘Electrically conductive composite films ofpolyaniline and nylon-6.6 are prepared by diffusing aniline followed by oxidative polymerization of aniline into nylon-6.6 matrix. In order to determine the diffusion coefficient for the chloride ion diffusion into the composite matrix electrochemically, galvanostatic pulse method is used and the diffusion coefficient is estimated to be -6.48× 10^-17 cm^2s^-1. The results are discussed in view of them being potential replacement materials for battery. electrodes and sensors devices.
文摘A novel high step-down non-isolated DC-DC converter has been proposed. The proposed converter consists of highly efficient non-isolated cell converters using bidirectional semiconductor power devices, and these cell converters are connected in ISOP （input series and output parallel）. The non-isolated ISOP converter achieves high step-down ratio of D/N, operating N cell converters under the duty ratio olD. Availability of the proposed converter has been shown by developing the 48 V-12 V laboratory prototype using two 24 V-12 V cell converters. Design consideration for the 48 V-3 V multicellular converter using four 12 V-3 V cell converters has been also conducted, and the potential to approach the efficiency of 97% has been discussed. The proposed topology is suitable for the POL （point of load） converters in the highly efficient next generation DC distribution system for data centers.
文摘We consider the problem of the two-point resistance on an m ×n cobweb network with a 2r boundary, which has never been solved before. Up to now researchers just only solved the cases with free boundary or null resistor boundary. This paper gives the general formulae of the resistance between any two nodes in both tinite and infinite cases using a method of direct summation pioneered by Tan [Z. Z. Tan, et al., J. Phys. A 46 （2013） 195202], which is simpler and can be easier to use in practice. This method contrasts the Green＇s function technique and the Laplacian matrix approach, which is difllcult to apply to the geometry of a cobweb with a 2r boundary. We deduce several interesting results according to our genera/formula. In the end we compare and illuminate our formulae with two examples. Our analysis gives the result directly as a single summation, and the result is mainly composed of the characteristic roots.
基金supported by the National Natural Science Foundation of China(51406223)
文摘With the large latent heat and low cost, the paraffin has been widely used in battery thermal management(BTM) system to improve the efficiency and cycling life of power battery. The numerical model of paraffin melting in a cavity has been established, and the effects on the solid–liquid phase change process have been investigated for the purpose of enhancing the heat transfer performance of paraffin-based BTM system. The results showed that the location of the heating wall had great effects on the melting process. The paraffin in the cavity melted most quickly when the heating wall located at the bottom. Furthermore, the effects of thermal conductivity and the velocity of the slip wall have been considered. The gradient of liquid fraction increased with the increase in thermal conductivity, and the melting process could be accelerated or delayed by the slip wall with different velocity.
