A new contact model of traveling wave ultrasonic motor （TWUSM） with a visco-elastic stator frictional layer was presented. In this model, the initial boundaries were revised, and the rotor revolution speed could he ...A new contact model of traveling wave ultrasonic motor （TWUSM） with a visco-elastic stator frictional layer was presented. In this model, the initial boundaries were revised, and the rotor revolution speed could he calculated iteratively. This model was compared with compliant slider and rigid stator model. The results of motor characteristics simulations showed that the motors based on this model would gain bigger stall torque. Then the friction and wear characteristics of two models were analyzed. The motors based on this model had lower coefficient of friction and better wear resistance.展开更多
In this paper, poly(butylene-terephthalate)-layered silicate of clay nanocomposites (NPBT) are reported. Their thermal properties, heat distortion temperature (HDT) and crystallization nucleation are investigated. NPB...In this paper, poly(butylene-terephthalate)-layered silicate of clay nanocomposites (NPBT) are reported. Their thermal properties, heat distortion temperature (HDT) and crystallization nucleation are investigated. NPBT samples have apparent viscosity over 0.85, HDT of 30℃ to 50℃ higher than that of poly (butylene-terephthalate) (PBT) for clay load from 1.0% to 10.0% (by mass), and higher capability to accommodate clay than other polymers. The nonisothermal crystallization experiments indicate that the better thermal degradation behavior and crystallization rate of NPBT are 50% higher than PBT, and its injection mould processing temperature is lowered from 110℃ to 55℃. NPBT samples are characterized by several techniques. X-ray shows an original clay interlayer distance enlarged from 1.0 nm to 2.5 nm, while both TBM and AFM indicate an average size from 30nm to lOOnm of exfoliated clay layers, and 3%(by mass) of particle agglomeration being phase separated from PBT matrix, which are factors on some mechanical properties decrease of NPBT. The disappearance of spherulitic morphology in NPBT resulted from layers nucleation is detected. Improving NPBT properties by treating clay with long chain organic reagent and controlling the way to load it is suggested.展开更多
In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In a...In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In addition,the thermal property and the microstructure of CPCM were also discussed in detail by means of polarization microscope and differential scanning calorimeter,respectively. According to the analysis of main influencial factors of the property of CPCM,the optimal preparing technique was determined. It was proved that CPCM could exhibit a good thermal property while phase transformation process took place,and a better appearance of the fabric modified with CPCM could be obtained due to the fact that in a warm circumstance,the liquid-state phase change material could be firmly enwrapped and embedded in the three-dimensional network all the time during the phase transformation. Besides,the fabric treated with CPCM had a high phase-transition enthalpy and an appropriate phase-transition temperature. As a result,a desirable temperature-adjustable function appeared.展开更多
According to the critical size ratio for the characteristic particle size to film thickness between grinding wheel and work, the machining mechanisms in abrasive jet precision finishing with grinding wheel as restrain...According to the critical size ratio for the characteristic particle size to film thickness between grinding wheel and work, the machining mechanisms in abrasive jet precision finishing with grinding wheel as restraint can be categorized into four states, namely, two-body lapping, three-body polishing, abrasive jet machining and fluid hydrodynamic shear stress machining. The critical transition condition of two-body lapping to three-body polishing was analyzed. The single abrasive material removal models of two-body lapping, three-body polishing, abrasive jet finishing and fluid hydrodynamic shear stress machining were proposed. Experiments were performed in the refited plane grinding machine for theoretical modes verification. It was found that experimental results agreed with academic modes and the modes validity was verified.展开更多
Cu/TEA-doped TiO2 nanoparticles were prepared by the sol-gel process. Titanium （IV） isoproxide, copper （II） nitrate trihydrate and triethanolamine were used as precursors and calcined at a temperature of 400℃ for...Cu/TEA-doped TiO2 nanoparticles were prepared by the sol-gel process. Titanium （IV） isoproxide, copper （II） nitrate trihydrate and triethanolamine were used as precursors and calcined at a temperature of 400℃ for 2 h with a heating rate of 10℃/min to produce powders. Different interstitial amounts of TEA were added in the range of 0 mol% to 15 mol% of TiO2. The X-ray diffractrometer patterns show the TiO2 nanocomposites have a high anatase phase. It was also apparent that doped TEA has an effect on the crystallite size of TiO2 composite nanoparticles. The morphology of the composite powders was characterized by scanning electron microscope. The photocatalytic activity of Cu/TEA-doped TiO2 nanoparticles was evaluated through the degradation of methylene blue under UV irradiation. The results showed that 1 mol% TEA of TiO2 nanocomposites exhibited high photocatalytic activity and a small crystallite size.展开更多
Conducting polymers （CPs） have been widely investigated due to their extraordinary advantages over the traditional materials, including wide and tunable electrical conductivity, facile production approach, high mech...Conducting polymers （CPs） have been widely investigated due to their extraordinary advantages over the traditional materials, including wide and tunable electrical conductivity, facile production approach, high mechanical stability, light weight, low cost and ease in material processing. Compared with bulk CPs, nanostructured CPs possess higher electrical conductivity, larger surface area, superior electro- chemical activity, which make them suitable for various ap- plications. Hybridization of CPs with other nanomaterials has obtained promising functional nanocomposites and achieved improved performance in different areas, such as energy sto- rage, sensors, energy harvesting and protection applications. In this review, recent progress on nanostructured CPs and their composites is summarized from research all over the world in more than 400 references, especially from the last three years. The relevant synthesizing experiences are outlined and abundant application examples are illustrated. The ap- proaches of production of nanostructured CPs are discussed and the efficacy and benefits of newest trends for the pre- paration of multifunctional nanomaterials/nanocomposites are presented. Mechanism of their electrical conductivity and the ways to tailor their properties are investigated. The re- maining challenges in developing better CPs based nanoma- terials are also elaborated.展开更多
Facile synthesis of an interfacial layer in organic solar cells (OSCs) is important for broadening material designs and upscaling photovoltaic conversion efficiency (PCE).Herein,a mild solution process of spin-coating...Facile synthesis of an interfacial layer in organic solar cells (OSCs) is important for broadening material designs and upscaling photovoltaic conversion efficiency (PCE).Herein,a mild solution process of spin-coating In(acac)3and Ga(acac)3isopropanol precursors followed by low-temperature thermal treatment was developed to fabricate In_(2)O_(3)and Ga2O3cathode buffer layers (CBLs).The introduction of In_(2)O_(3)or Ga2O3CBLs endows PM6:Y6-based OSCs with outstanding performance and high PCEs of 16.17%and 16.01%,respectively.Comparison studies present that the In_(2)O_(3)layer possesses a work function (WF) of 4.58 eV,which is more favorable for the formation of ohmic contact compared with the Ga2O3layer with a WF of 5.06 eV and leads to a higher open circuit voltage for the former devices.Electrochemical impedance spectroscopy was performed to reveal how In_(2)O_(3)and Ga2O3affect the internal charge transfer and the origin of their performance difference.Although In_(2)O_(3)possesses lower series resistance loss,Ga2O3has a higher recombination resistance,which enhances the device fill factor and compensates for its series resistance loss to some extent.Comparative analysis of the photo-physics of In_(2)O_(3)and Ga2O3suggests that both are excellent CBLs for highly efficient OSCs.展开更多
基金Sponsored by the Natural Sciences Foundation of China (Grant No 50575055)the National 973 Key Development Project in Fundamental Science Research (Grant No2007CB607602)
文摘A new contact model of traveling wave ultrasonic motor （TWUSM） with a visco-elastic stator frictional layer was presented. In this model, the initial boundaries were revised, and the rotor revolution speed could he calculated iteratively. This model was compared with compliant slider and rigid stator model. The results of motor characteristics simulations showed that the motors based on this model would gain bigger stall torque. Then the friction and wear characteristics of two models were analyzed. The motors based on this model had lower coefficient of friction and better wear resistance.
基金Supported by China National Petroleum Corporation Innovation Foundation(No.J02060)and Subsidized by Special Funds for Major State Basic Research Projects(No.G1999064800)
文摘In this paper, poly(butylene-terephthalate)-layered silicate of clay nanocomposites (NPBT) are reported. Their thermal properties, heat distortion temperature (HDT) and crystallization nucleation are investigated. NPBT samples have apparent viscosity over 0.85, HDT of 30℃ to 50℃ higher than that of poly (butylene-terephthalate) (PBT) for clay load from 1.0% to 10.0% (by mass), and higher capability to accommodate clay than other polymers. The nonisothermal crystallization experiments indicate that the better thermal degradation behavior and crystallization rate of NPBT are 50% higher than PBT, and its injection mould processing temperature is lowered from 110℃ to 55℃. NPBT samples are characterized by several techniques. X-ray shows an original clay interlayer distance enlarged from 1.0 nm to 2.5 nm, while both TBM and AFM indicate an average size from 30nm to lOOnm of exfoliated clay layers, and 3%(by mass) of particle agglomeration being phase separated from PBT matrix, which are factors on some mechanical properties decrease of NPBT. The disappearance of spherulitic morphology in NPBT resulted from layers nucleation is detected. Improving NPBT properties by treating clay with long chain organic reagent and controlling the way to load it is suggested.
基金Fujian Province I mportant Science and Technology Development Fund,China (No.2005Z17)
文摘In this study,the sol-gel method was introduced to prepare the composite phase change material (CPCM). The CPCM was added to fabric with coating techniques and the thermal activity of modified fabric was studied. In addition,the thermal property and the microstructure of CPCM were also discussed in detail by means of polarization microscope and differential scanning calorimeter,respectively. According to the analysis of main influencial factors of the property of CPCM,the optimal preparing technique was determined. It was proved that CPCM could exhibit a good thermal property while phase transformation process took place,and a better appearance of the fabric modified with CPCM could be obtained due to the fact that in a warm circumstance,the liquid-state phase change material could be firmly enwrapped and embedded in the three-dimensional network all the time during the phase transformation. Besides,the fabric treated with CPCM had a high phase-transition enthalpy and an appropriate phase-transition temperature. As a result,a desirable temperature-adjustable function appeared.
基金Sponsored by the National Natural Science Foundation of China (Grant No 50475052)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No 20040145001)
文摘According to the critical size ratio for the characteristic particle size to film thickness between grinding wheel and work, the machining mechanisms in abrasive jet precision finishing with grinding wheel as restraint can be categorized into four states, namely, two-body lapping, three-body polishing, abrasive jet machining and fluid hydrodynamic shear stress machining. The critical transition condition of two-body lapping to three-body polishing was analyzed. The single abrasive material removal models of two-body lapping, three-body polishing, abrasive jet finishing and fluid hydrodynamic shear stress machining were proposed. Experiments were performed in the refited plane grinding machine for theoretical modes verification. It was found that experimental results agreed with academic modes and the modes validity was verified.
文摘Cu/TEA-doped TiO2 nanoparticles were prepared by the sol-gel process. Titanium （IV） isoproxide, copper （II） nitrate trihydrate and triethanolamine were used as precursors and calcined at a temperature of 400℃ for 2 h with a heating rate of 10℃/min to produce powders. Different interstitial amounts of TEA were added in the range of 0 mol% to 15 mol% of TiO2. The X-ray diffractrometer patterns show the TiO2 nanocomposites have a high anatase phase. It was also apparent that doped TEA has an effect on the crystallite size of TiO2 composite nanoparticles. The morphology of the composite powders was characterized by scanning electron microscope. The photocatalytic activity of Cu/TEA-doped TiO2 nanoparticles was evaluated through the degradation of methylene blue under UV irradiation. The results showed that 1 mol% TEA of TiO2 nanocomposites exhibited high photocatalytic activity and a small crystallite size.
基金supported by the National Institute of Food and Agriculture,USDA and AU-IGP award
文摘Conducting polymers （CPs） have been widely investigated due to their extraordinary advantages over the traditional materials, including wide and tunable electrical conductivity, facile production approach, high mechanical stability, light weight, low cost and ease in material processing. Compared with bulk CPs, nanostructured CPs possess higher electrical conductivity, larger surface area, superior electro- chemical activity, which make them suitable for various ap- plications. Hybridization of CPs with other nanomaterials has obtained promising functional nanocomposites and achieved improved performance in different areas, such as energy sto- rage, sensors, energy harvesting and protection applications. In this review, recent progress on nanostructured CPs and their composites is summarized from research all over the world in more than 400 references, especially from the last three years. The relevant synthesizing experiences are outlined and abundant application examples are illustrated. The ap- proaches of production of nanostructured CPs are discussed and the efficacy and benefits of newest trends for the pre- paration of multifunctional nanomaterials/nanocomposites are presented. Mechanism of their electrical conductivity and the ways to tailor their properties are investigated. The re- maining challenges in developing better CPs based nanoma- terials are also elaborated.
基金supported by the National Natural Science Foundation of China (51573042,61874148,51873007,5181101540 and 21835006)the Fundamental Research Funds for the Central Universities in China (2019MS025 and 2018MS032)the State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (LAPS20003)。
文摘Facile synthesis of an interfacial layer in organic solar cells (OSCs) is important for broadening material designs and upscaling photovoltaic conversion efficiency (PCE).Herein,a mild solution process of spin-coating In(acac)3and Ga(acac)3isopropanol precursors followed by low-temperature thermal treatment was developed to fabricate In_(2)O_(3)and Ga2O3cathode buffer layers (CBLs).The introduction of In_(2)O_(3)or Ga2O3CBLs endows PM6:Y6-based OSCs with outstanding performance and high PCEs of 16.17%and 16.01%,respectively.Comparison studies present that the In_(2)O_(3)layer possesses a work function (WF) of 4.58 eV,which is more favorable for the formation of ohmic contact compared with the Ga2O3layer with a WF of 5.06 eV and leads to a higher open circuit voltage for the former devices.Electrochemical impedance spectroscopy was performed to reveal how In_(2)O_(3)and Ga2O3affect the internal charge transfer and the origin of their performance difference.Although In_(2)O_(3)possesses lower series resistance loss,Ga2O3has a higher recombination resistance,which enhances the device fill factor and compensates for its series resistance loss to some extent.Comparative analysis of the photo-physics of In_(2)O_(3)and Ga2O3suggests that both are excellent CBLs for highly efficient OSCs.
