Poly(vinylidene fluoride) (PVDF) has attracted much attention due to its mechanical strength and piezoelectric properties, and has been widely used in diverse fields. Carbon nanotubes (CNTs) have been considered as id...
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Poly(vinylidene fluoride) (PVDF) has attracted much attention due to its mechanical strength and piezoelectric properties, and has been widely used in diverse fields. Carbon nanotubes (CNTs) have been considered as ideal reinforcing fillers for polymer because of extraordinary mechanical strength and high electrical conductivity. The PVDF/CNTs composite will be promising and of great potential applications in electromechanical devices design considering their attractive electrical and mechanical properties from PVDF and CNTs. In this study, we develop a controllable and adjustable method for noncovalent wrapping CNTs with PVDF using a supercritical (SC) CO 2 antisolvent-induced polymer epitaxy method, which have a great potential to improve the compatibility between CNTs and polymer. Transmission electron microscopy (TEM) results showed that with the variation of experimental conditions, the micro morphology of the obtained materials can be varied. For the single-walled CNTs (SWCNTs), with the increase of SC CO 2 pressure, the PVDF wrapping degree on SWCNTs increases. In further study we can find that there is the formation of the nanohybrid structure with nanocrystals wrapping on SWCNTs. Firstly, a few of molecular chains precipitated on the surface of SWCNTs, and then form a primary particle from several nucleuses, and followed it might grow as a spathic nanocrystal. During the process, the PVDF nanocrystals on the SWCNT could be regarded as a steady intermediate state, which could further form ordered patterning of nanohybrid structure when suitable experimental conditions are achieved.
Stainless steels form oxide films during the process of hot rolling, which affects their surface quality and following process. the geometrical structures and cohesive energies as well as electronic characteristics of...
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Stainless steels form oxide films during the process of hot rolling, which affects their surface quality and following process. the geometrical structures and cohesive energies as well as electronic characteristics of the FeO/Fe-M(M=Ni, Cr) interfaces were investigated using a first-principles pseudopotential plane-wave method based on density functional theory. The result shows that the values of adhesive energy of FeO/Fe-M(M=Ni, Cr) interfaces decreased in order of FeO/Fe>FeO/Fe-Cr>FeO/Fe-Ni. Removal of oxide films on the Fe-Ni stainless steel surface changes relatively easier thinking from the standpoint of pickling after hot rolling.
The Ni-P plating was prepared on AZ91D magnesium alloy by electroless deposit. The effect of heat treatment temperatures on the microstructure and property of the Ni-P deposit was investigated by means of SEM, XRD, TE...
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The Ni-P plating was prepared on AZ91D magnesium alloy by electroless deposit. The effect of heat treatment temperatures on the microstructure and property of the Ni-P deposit was investigated by means of SEM, XRD, TEM, microhardness test and spray corrosion tests. The results show that the plating with 6.22 wt% phosphorus consists of amorphous and nanocrystalline microstructure. Nanocrystalline nickel forms firstly in the amorphous during annealing. The grain sizes of the nickel grow rapidly during crystallization. Ni3P and a little of Ni12P5 phases form in nickel matrix of the deposited coating after annealing. The maximium adhesion strength of 3.7 MPa is obtained for the deposited coating annealed at 350°C. The maximum hardness of the coating is 825 HV when annealing the temperature reachs 400°C. The salt spraying test shows that good corrosion resistance of the plating is observed, however, the corrosion resistance gradually declines with increasing annealing temperature.
A nano-modified chitosan was prepared by oxidation methodology and nanotechnology. Medical antibacterial latex was prepared using the nano-modified chitosan as antibacterial agent and natural latex by mechanical blend...
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A nano-modified chitosan was prepared by oxidation methodology and nanotechnology. Medical antibacterial latex was prepared using the nano-modified chitosan as antibacterial agent and natural latex by mechanical blending method. The microstructure of the medical antibacterial latex was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that chitosan particles are spherical with particle size of 10 nm and are evenly dispersed in latex matrix. The antibacterial property against Escherichia coli of medical antibacterial latex was tested. The result indicates the antibacterial medical latex has well antibacterial property, with the inhibition ring's diameter far more than 7 mm.
The impact of spinal cord injury (SCI) on potential functional reorganization in neuronal populations in motor cortical areas remains unknown, though its influence on functional recovery may be significant. The cortic...
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The impact of spinal cord injury (SCI) on potential functional reorganization in neuronal populations in motor cortical areas remains unknown, though its influence on functional recovery may be significant. The cortical neuronal data was recorded from a monkey while it was trained to walk bipedally on a treadmill both before and after spinal cord injury. By using the correlation coefficients between different neurons, we constructed graphs for multiple steps in different sessions. The global efficiency of the graph was then calculated to investigate the effect of SCI on the neuronal activity patterns and how the correlation between the neurons changes as the functional recovery continued. Our results indicate that the observed significant changes in neuronal activity patterns in the motor cortex, although preliminary, suggest that the patterns of functional reorganization (neural plasticity) in motor areas of the cortex correlate and contribute to the functional recovery.
An ultrathin film of MgF2 is inserted into the hole transport layer NPB of the traditional OLEDs(organic electroluminescent devices), the devices with the structure of ITO/NPB(10 nm)/MgF2(x nm)/NPB(20 nm)/Alq3(30 nm)/...
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An ultrathin film of MgF2 is inserted into the hole transport layer NPB of the traditional OLEDs(organic electroluminescent devices), the devices with the structure of ITO/NPB(10 nm)/MgF2(x nm)/NPB(20 nm)/Alq3(30 nm)/Al(30 nm) are fabricated. The results show that the MgF2 interlayer with suitable thickness can decrease the turn on voltage and increase the efficiency of the device. In this experiment, the turn on voltage of the device with 0.5 nm-thickness MgF2 layer is 2.3 V, which is 2 V lower than that of the OLED without MgF2 layer. The maximum luminous efficiency and power efficiency of the device with 1.0 nm-thickness MgF2 layer are 3.93 cd/A and 1.58 lm/W, respectively, which are increased by 95% and 110% compared with that of the OLED without MgF2 interlayer, respectively.
The fatigue properties of the TIG welded joints of both AZ31B magnesium alloy and 5A06 aluminum alloy were investigated. The four types of welded joints were used in fatigue tests, such us butt joints, transverse cros...
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The fatigue properties of the TIG welded joints of both AZ31B magnesium alloy and 5A06 aluminum alloy were investigated. The four types of welded joints were used in fatigue tests, such us butt joints, transverse cross joints, fillet joints and lateral connecting joints. The fatigue strengths at 2 × 10^6 cycles of the four welded joints of AZ31B magnesium alloy are 39. 0 MPa, 24. 4 MPa, 32. 1 MPa and 24. 2 MPa, which are 55. 0% , 42. 2%, 78. 0% and 50. 2% of that of 5A06 aluminum alloy, respectively. The fatigue strength levels at slope m = 3 of the aluminum alloy＇ s welded joints are mostly higher than the FAT recommended by the International Institute of Welding （ HW） , while those of the magnesium alloy＇ s welded joints are all lower than the FAT. It is indicated that the FAT of magnesium alloy＇ s welded joints should be established as early as possible in order to be applied in the design of magnesium alloy＇ s welded structures.
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