اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدA study of random resistor-capacitor-diode networks to assess the electromagnetic properties of carbon nanotube filled polymers
191
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We determined the frequency dependent effective permittivity of a large ternary network of randomly positioned resistors, capacitors, and diodes. A linear circuit analysis of such systems is shown to match the experimental dielectric response of single-walled carbon nanotube (SWCNT) filled polymers. This modeling method is able to reproduce the two most important features of SWCNT filled composites, i.e. the low frequency dispersion and dipolar relaxation. As a result of the modeling important physical conclusion proved by the experimental data was done: the low frequency behavior of SWCNT-filled polymer composites is mostly caused by the fraction of semiconducting SWCNTs.
قيم البحث
اقرأ أيضاً
Electronic transport through a single-wall metallic carbon nanotube weakly coupled to one ferromagnetic and one nonmagnetic lead is analyzed in the sequential tunneling limit. It is shown that both the spin and charge currents flowing through such sy
stems are highly asymmetric with respect to the bias reversal. As a consequence, nanotubes coupled to one nonmagnetic and one ferromagnetic lead can be effectively used as spin diodes whose functionality can be additionally controlled by a gate voltage.
Recently, it was suggested that the polarization dependence of light absorption to a single-walled carbon nanotube is altered by carrier doping. We specify theoretically the doping level at which the polarization anisotropy is reversed by plasmon exc
itation. The plasmon energy is mainly determined by the diameter of a nanotube, because pseudospin makes the energy independent of the details of the band structure. We find that the effect of doping on the Coulomb interaction appears through the screened exchange energy, which can be observed as changes in the absorption peak positions. Our results strongly suggest the possibility that oriented nanotubes function as a polarization switch.
Recent air pollution issues have raised significant attention to develop efficient air filters, and one of the most promising candidates is that enabled by nanofibers. We explore here selective molecular capture mechanism for volatile organic compoun
ds in carbon nanotube networks by performing atomistic simulations. The results are discussed with respect to the two key parameters that define the performance of nanofiltration, i.e. the capture efficiency and flow resistance, which validate the advantage of carbon nanotube networks with high surface-to-volume ratio and atomistically smooth surfaces. We also reveal the important roles of interfacial adhesion and diffusion that govern selective gas transport through the network.
Prompted by recent reports on $sqrt{3} times sqrt{3}$ graphene superlattices with intrinsic inter-valley interactions, we perform first-principles calculations to investigate the electronic properties of periodically nitrogen-doped graphene and carbo
n nanotube nanostructures. In these structures, nitrogen atoms substitute one-sixth of the carbon atoms in the pristine hexagonal lattices with exact periodicity to form perfect $sqrt{3} times sqrt{3}$ superlattices of graphene and carbon nanotubes. Multiple nanostructures of $sqrt{3} times sqrt{3}$ graphene ribbons and carbon nanotubes are explored, and all configurations show nonmagnetic and metallic behaviors. The transport properties of $sqrt{3} times sqrt{3}$ graphene and carbon nanotube superlattices are calculated utilizing the non-equilibrium Greens function formalism combined with density functional theory. The transmission spectrum through the pristine and $sqrt{3} times sqrt{3}$ armchair carbon nanotube heterostructure shows quantized behavior under certain circumstances.
We observe current rectification in a molecular diode consisting of a semiconducting single-wall carbon nanotube and an impurity. One half of the nanotube has no impurity, and it has a current-voltage (I-V) charcteristic of a typical semiconducting n
anotube. The other half of the nanotube has the impurity on it, and its I-V characteristic is that of a diode. Current in the nanotube diode is carried by holes transported through the molecules one-dimensional subbands. At 77 Kelvin we observe a step-wise increase in the current through the diode as a function of gate voltage, showing that we can control the number of occupied one-dimensional subbands through electrostatic doping.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
