VLSI design of APT-VDF using novel variable block sized ternary adder and multiplier

Nowadays, Variable digital filters (VDF) play an essential role in the field of communication and signal processing. The desired frequency response of any prototype filter can be obtained by developing an All Pass Transformation (APT) based Variable digital filter (APT-VDF) that maintains an exhaustive control over the cut off frequency. The performance of the APT-VDF is limited by its speed and area utilization. In this paper, the pipelined APT-VDF is modified by developing a new Variable Block Sized Ternary Adder (VBS-TA) and a modified Ternary multiplier for the fast realization of the filter structure. Because, the fundamental arithmetic operations involved in the design of APT-VDF are addition and multiplication. The ternary logic transmits more data through interconnection wire, and hence the ternary logic based arithmetic requires fewer components and interconnections. The proposed VBS-TA increases the speed of the addition process by skipping the carry propagation with the help of ternary compound gates. This VBS-TA can also be used to boost up the speed of the multiplier circuit in the APT-VDF filter. Furthermore, the ternary multiplier is modified by introducing a divide and conquers approach in the partial product generation part. The simulation results show that the proposed APT-VDF overtakes the existing VDFs in terms of delay, power and area utilization. It consumes only 0.289Wpower with a latency of 9.24 ns. Also, it achieves an operating frequency of 210.87 MHz, and it is much better than the existing VDFs.     

Three-dimensional simulation studies on electrostatic predictions for carbon nanotube field effect transistors

Analysis of the electrostatic characteristics and the gate capacitance of typical nanostructured carbon nanotube field effect transistors (CNTFETs) were performed numerically. A previously developed parallelized electrostatic Poisson's equation solver (PPES) is employed, coupled with a parallel adaptive mesh refinement (PAMR) to improve the numerical accuracy near the region where variation of potentials are significant. CNTFETs with four typical configurations of the gate electrode, the bottom gate (BG), the double gate (DG), the top gate (TG), and the surrounding gate (SG) were simulated. Effects of the nanotube arrangement and the gate length on the gate capacitance are presented and discussed. The simulation results show that SG-CNTFET possesses the largest gate capacitance among various structures. However, TG-CNTFET is recommended for practical applications by taking into account both the device performance and the difficulty of fabrication. According to the simulated gate capacitance, estimation of the on-state current of CNTFETs is possible.     

Performances of carbon nanotube field effect transistors with altered channel length

The influence of channel length on the performances of carbon nanotube field effect transistors(CNT-FETs) has been studied.Buffered oxide etching was used to remove approximately a 60 nm layer from the original 100 nm silicon dioxide layer,to thin the dielectric layer of the back gate.Channel length of the CNT-FETs was changed along with the etching process.The dependence of drain-source current on gate voltage was measured to analyze the performance of the CNT-FETs,including the transconductance,carrier mo...     

Terahertz transistors based on aligned carbon nanotube arrays

The wireless communication technology has greatly pro-moted the industry's demand for higher operating frequen-cies and wider bandwidth devices.In recent years,...     

Label-free protein detection based on vertically aligned carbon nanotube gated field-effect transistors

Reliable detection using aptamers, which is key for monitoring complex metabolites and proteins, is often hindered by the lack of a robust sensing scheme capable of high density fabrication. As a result, current research is focusing on the coexistence of nanomaterials and conventional CMOS processes for the fabrication of the next generation of electrochemical detectors. Herein, we report the successful electrochemical detection of the protein thrombin utilizing a novel thrombin aptamer functionalized single-walled carbon nanotube (SWNT) gated silicon-based metal–oxide-semiconductor field-effect transistor (MOSFET). Owing to thrombin's positive charge in an aqueous environment (pH = 5.5), the drain current of the SWNT gated MOSFET increased linearly with increasing thrombin concentration, resulting in sensitivities as high as 33 μA/(μM mm²). A theoretical model has been presented to explain the operating principle of this gated MOSFET-based biosensor and revealed that the electron density in the channel increases with the addition of positively charged thrombin, in addition to flat-band and threshold voltage modification due to the work function of SWNTs. Such advanced MOSFET-based sensing schemes present considerable advantages over traditional methodologies in view of its miniaturization, low cost, and facile fabrication, paving the way for the ultimate realization of a multi-analyte lab-on-chip.     

A novel conductive humidity sensor based on field ionization from carbon nanotubes

A novel, high efficiency detector for humidity is described, in which the multiwall nanotubes grown on the silicon substrates serve as anode and ITO film glass plate as cathode are separated and insulated by a glass insulator. Application of a positive bias to the multiwall nanotubes generates high electric field sufficient to field-ionize passing gas-phase atoms especially for water vapor. By monitoring the prebreakdown current, relative humidity can be determined. The sensitivity factor (I_75.8%/I_12%) is about 229.4. The recovery time from 53.4 to 6.8% RH for the humidity sensor is about 10 s.     

A micropipette system based on low driving voltage carbon nanotube actuator

Microsystem Technologies - We have fabricated a pipette system driven by a carbon nanotube (CNT) electroactive polymer (EAP) actuator, equipped with commercially available two- and three-way...     

一种基于电容倍增的无电容式LDO

设计了一种基于电容倍增的无电容式LDO,将电容倍增模块嵌入到了误差运算放大器的第一级,提升了系统的环路带宽,有良好的瞬态响应。电路通过0.13μm标准CMOS工艺仿真实现,仿真结果显示,系统静态功耗为42μW,当负载从0⁵0 mA变化时,电压最大波动为87 mV,建立时间为2.5μs。     

A new construction adder based on Chinese abacus algorithm

A new construction adder based on Chinese abacus algorithm is presented in this paper. There are two kinds of beads used in this construction. Each column element has three higher beads with a weight of four and three lower beads with a weight of one. The proposed 32-bit adder contains eight column elements. The construction was simulated by the technology of TSMC 0.18 μm CMOS process. Layout was also made by the same technology. The maximum delay of the 32-bit abacus adder is 0.91 ns and 14% less than that of Carry Look-ahead Adders for 0.18 μm technology. The power consumption of the abacus adder is 3.1 mW and 28% less than that of Carry Look-ahead Adders for 0.18 μm technology. Recent researches are compared with the proposed adder. The construction was also simulated by Predictive Technology Model. The PTM results also presented. The use of Chinese abacus approach offers a competitive technique with respect to other adders.     

基于双Booth 2编码的双有限域模乘法器设计与实现

采用双Booth 2编码技术,对高基radix-16 Montgomery模乘法器进行了优化设计,减小了电路面积,提高了模乘运算速度。使用SMIC0.18μm标准单元工艺库综合后,计算256bit有限域GF(P)上的模乘只需要0.51μs。     

A novel technique for fabrication of micro- and nanofluidic device with embedded single carbon nanotube

This paper describes a novel technique for fabrication of micro- and nanofluidic device that consists of a carbon nanotube (CNT) and a polydimethylsiloxane (PDMS) microchannel. Single CNT was placed at desired locations using dielectrophoresis (DEP) and PDMS microchannel was constructed on the aligned CNT via photolithography and soft lithography techniques. This technique enables a CNT to be seamlessly embedded in a PDMS microchannel. Moreover, controlling the PDMS curing condition enables the construction of the device with or without a CNT (the device without CNT has a trace nanochannel in PDMS). Preliminary flow tests such as capillary effect and pressure-driven flow were performed with the fabricated devices. In the capillary effect tests, the flow stopped at the nanochannel in both devices. In the pressure-driven flow lower flow resistance was observed in the device with a CNT.     

Surface acoustic wave gas sensors based on polyisobutylene and carbon nanotube composites

Surface acoustic wave (SAW) gas sensors based on polyisobutylene (PIB) and composites (PIB and carbon nanotubes) as sensitive layers were investigated for the detection of octane and toluene (volatile organic compounds) and other atmospheric pollutants (H₂, CO, NO₂ and NH₃) at room temperature. In order to study the effect of nanotubes in the response of SAW sensors, several composites based on PIB with different percentages of multiwalled carbon nanotubes (MWNTs) were tested and compared to the response obtained from PIB SAW sensors. Sensors exhibit high responses and selectivity to volatile organic compounds (VOCs) with fast response and recovery times as well as good repeatability and reproducibility. Experimental results show as small percentages of nanotubes improve the response to octane.     

基于碳纳米管／壳聚糖／纳米金活性界面的辣根过氧化物酶传感器研制

利用壳聚糖(Chitosan)的成膜性能以及碳纳米管在其中良好的分散性,在玻碳电极表面首先形成碳纳米管/壳聚糖膜,通过膜表面丰富的氨基与纳米金的强静电吸附,在玻碳电极表面获得稳定的纳米Au修饰层,吸附固定辣根过氧化物酶(HRP),制得无需电子媒介的H2O2生物传感器.循环伏安曲线显示,当加入H2O2溶液后,阴极峰电流增大,而阳极电流相应减少,表明通过碳纳米管/壳聚糖/纳米金活性界面固定在玻碳电极表面的HRP与电极之间有良好的直接电子传导能力,对H2O2的还原具有良好的电催化活性,H2O2的测定线性范围为5×10-5～2.7×10-3mol/L.     

Design of a one-way nanovalve based on carbon nanotube junction and C60

We report the conceptual construction of a one-way nanovalve based on a carbon nanotube intramolecular junction and a C₆₀. Using molecular dynamics simulations, we demonstrate the flow behavior of helium through the nanovalve as controlled by the pressure balance around C₆₀. The van der Waals interaction between C₆₀ and carbon nanotube keeps C₆₀ close to the junction, while the pressure balance around C₆₀ can juggle it between two adsorption sites, which in turn closes or opens the nanovalve.     

基于量子傅里叶变换算法的量子乘法器

乘法运算是许多量子算法中的基本运算之一.为了实现量子乘法运算并且尽可能少地使用辅助量子比特,提出了一种基于量子傅里叶变换算法的量子乘法器.在量子傅里叶加法电路基础上,设计了量子移位电路,并实现了两个n位二进制无符号数相乘的量子电路,其时间复杂度为O(n3).使用IBM提供的开源量子计算工具包Qiskit分别验证了两个2...     

Design and analysis of carbon nanotube FET based quaternary full adders

CMOS binary logic is limited by short channel effects, power density, and interconnection restrictions. The effective solution is non-silicon multiple-valued logic (MVL) computing. This study presents two high-performance quaternary full adder cells based on carbon nanotube field effect transistors (CNTFETs). The proposed designs use the unique properties of CNTFETs such as achieving a desired threshold voltage by adjusting the carbon nanotube diameters and having the same mobility as p-type and n-type devices. The proposed circuits were simulated under various test conditions using the Synopsys HSPICE simulator with the 32 nm Stanford comprehensive CNTFET model. The proposed designs have on average 32% lower delay, 68% average power, 83% energy consumption, and 77% static power compared to current state-of-the-art quaternary full adders. Simulation results indicated that the proposed designs are robust against process, voltage, and temperature variations, and are noise tolerant.     

基于铂纳米颗粒修饰碳纳米管Nafion膜电极的葡萄糖传感器

将分散在Nafion溶液中的多壁碳纳米管(MWNT)修饰玻碳电极(GCE),再在该膜上电沉积一层铂纳米粒子,制成铂纳米颗粒修饰的碳纳米管Nafion膜电极(Nafion-MWNT-Pt/GCE),并吸附固定葡萄糖氧化酶(GOD),构建电流型葡萄糖生物传感器。考察了Nafion-MWNT-Pt/GCE的电化学特性,发现沉积铂纳米粒子后,Fe(CN)6-3/-4电对在Nafion-MWNT-Pt/GCE上的氧化峰和还原蜂之间的电势差(ΔE)为179mV,小于未修饰铂纳米粒子的碳纳米管Nafion膜电极的ΔE(190mV),表明碳纳米管上电沉积的铂纳米粒子可加速电极的电子传递,电化学反应具有良好的可逆性。此外,铂纳米粒子尚具有良好的催化H2O2氧化的特性,H2O2在Nafion-MWNT-Pt/GCE上的计时电流响应明显增大。基于Nafion-MWNT-Pt/GCE的葡萄糖生物传感器显示了良好的传感性能,其检测线性范围为2.1×10-5～7.6×10-3mol/L,检测下限为1.0×10-6mol/L。     

A compact model for transition metal dichalcogenide field effect transistors with effects of interface traps

Dear editor, Two-dimensional transition metal dichalcogenide (TMD) materials, such as molybdenum disulphide (MoS2), are considered as promising channel candidat...     

基于钳位电路的碳纳米管薄膜声源系统优化

碳纳米管薄膜是一种由碳原子组成的新型纳米材料,可被制作成一种基于热致发声效应的扬声器。针对碳纳米管薄膜电-热-声系统的频率失真问题,提出添加钳位电路的解决方法,并进行了理论研究和实验验证。结果表明,加入钳位电路后,系统输出的声波频率与输入电压频率变为一致,且声能量显著增大,声压级提高约5 d B。与传统叠加直流偏置电压的方法相比,无需直流电源,降低了系统功耗。     

Influence of Zn ion implantation on structures and field emission properties of multi-walled carbon nanotube arrays

The structures and field emission properties of multi-walled carbon nanotube arrays implanted with Zn+ by MEVVA ion implanter have been investigated.The results revealed that Zn+implantation induced structural damage and that the top of carbon nanotubes with multi-layered graphite structure were transformed into carbon nanowires with amorphous structure.Meanwhile,C:Zn solid solution was synthesized after Zn+ implantation.The turn-on field and threshold field were 0.80 and 1.31 V/μm,respectively for original...