Nano-scale metallization of Au on flexible polyimide substrate by reversal imprint and lift-off process

The nano-scale metallization of Au on flexible polyimide substrate by reversal imprint and lift-off process was investigated. The nano-scale mold was fabricated; the anti-adhesion property of nanometer-size Si-mold was improved and the surface free energy was calculated with the contact angle measurement. The ∼150 nm width Au nano-wires were successfully fabricated on Si and on flexible polyimide substrate with the proposed process. The PMMA thickness dependent trend with reversal imprinting and Au nano-wires lift-off results were also investigated by SEM analysis.     

Establishment of a cutting force model and study of the stress–strain distribution in nano-scale copper material orthogonal cutting

This article focuses on the establishment of a cutting force calculation model in terms of nano-scale orthogonal cutting, and investigates the stress–strain distribution of single-crystal copper that occurs in terms of nano cutting. The cutting force that occurs during the nano-scale cutting of single-crystal copper, and also its changes under different situations, can be found in this study. The molecular dynamics (MD) model was proposed to evaluate the displacement components of the atom in any temporary situation on the nano-scale cutting. The atom and lattice were regarded as the node and element, respectively. The shape function concept of the finite element method (FEM) is used to calculate the equivalent strain of the nodal atom and element. The equivalent stress–strain relationship equation was acquired by nano-scale thin-film tensile simulation in this study, and was used to further calculate the equivalent stress that occurs under the equivalent strain. Subsequently, a stress–strain distribution during nano-scale orthogonal cutting can be acquired.     

High strength-ductility nano-structured high manganese steel produced by cryogenic asymmetry-rolling

A bulk nanostructured twinning-induced plasticity (TWIP) steel with high ductility and high strength was fabricated by cryogenic asymmetry-rolling (cryo-ASR) and subsequent recovery treatment. It was found that the cryo-ASRed TWIP steels exhibit simultaneous improvements in the ductility, strength and work hardening. Typical microstructures of the cryo-ASR TWIP steel were characterized by shear bands and intensive mechanical nano-sized twins induced by cryogenic deformation. These mechanical nano-scale twins remain thermally stable during the subsequent recovery treatment. It is believed that the ductility enhancement and high work-hardening ability for the cryo-ASR TWIP steels should be mainly attributed to the high-density pre-existing nano-scale twins.     

An accurate analytical I-V model for sub-90-nm MOSFETs and its application to read static noise margin modeling

We propose an accurate model to describe the I-V characteristics of a sub-90-nm metal-oxide-semiconductor field-effect transistor(MOSFET) in the linear and saturation regions for fast analytical calculation of the current.The model is based on the BSIM3v3 model.Instead of using constant threshold voltage and early voltage,as is assumed in the BSIM3v3 model,we define these voltages as functions of the gate-source voltage.The accuracy of the model is verified by comparison with HSPICE for the 90-,65-,45-,and 32-nm CMOS technologies.The model shows better accuracy than the nth-power and BSIM3v3 models.Then,we use the proposed I-V model to calculate the read static noise margin(SNM) of nano-scale conventional 6T static random-access memory(SRAM) cells with high accuracy.We calculate the read SNM by approximating the inverter transfer voltage characteristic of the cell in the regions where vertices of the maximum square of the butterfly curves are placed.The results for the SNM are also in excellent agreement with those of the HSPICE simulation for 90-,65-,45-,and 32-nm technologies.Verification in the presence of process variations and negative bias temperature instability(NBTI) shows that the model can accurately predict the minimum supply voltage required for a target yield.     

Nano-TiO2/HIPS母料流变性能的研究

采用Rosand Rheometer流变仪研究了nano-TiO2/HIPS母料及EVA蜡改性母料的流变性能。结果表明,nano-TiO2对母料的表观粘度影响较小。在nano-TiO2质量分数低于20％时，表观粘度仅略高于纯HIPS。在低剪切速率下。nano-TiO2可加速熔体偏离牛顿流体的速度。体系的粘弹性增强；而在较高剪切速率下则相反。EVA蜡可在较大范围内调整母料体系的流变性能。在低剪切速率下，EVA蜡质量分数超过5％就可明显改善体系的流动性，且体系流动行为接近牛顿流体，粘弹性很弱；在高剪切速率下，EVA蜡对体系的流动性影响不大，流变行为及牯弹行为与纯HIPS相当。原子力显微镜测试表明。采用EVA蜡改性的nano-TiO2/HIPS母料。可得到表观及分散性良好的制品。     

In situ gradient nano-scale fibril formation during polypropylene (PP)/polystyrene (PS) composite fine fiber processing

The nano-scale dispersed fibrils with gradient distribution in PP/PS composite fine fibers were observed by in situ formation during its melt spinning process. The morphology development of polyblends, from granule to as-spun fiber as well as drawn fiber with various PS content from 2 to 8 wt% were investigated. The morphology conversion of PS dispersed phase from ellipse to gradient nano-scale fibril along the radial direction of as-spun composite fibers took palace at 4 wt% by weight of PS component, suggesting the presence of break-up in fiber center and the limited coalescence, especially in 8 wt% PS as-spun composite fibers. This morphology diversity was attributed to the radial variation of parameters including temperature, viscosity, axial velocity and stress in spinning path and was in good agreement with the droplet deformation criteria based on the reduced capillary number. In addition, the post hot-drawing process slightly influence the size and distribution of PS phase in cross-section of composite drawn fibers, while the rheological properties of PP, PS and polyblends were found to be correlated to the morphology of PP/PS composites.     

聚丙烯的高性能化研究

在小型反应器内合成了不含及含有成核剂的聚丙烯(PP)、双峰聚丙烯(BMPP)和聚丙烯共聚物(PPc)，并用纳米CaCO3改性PPc。研究结果表明：釜内成核的PP和BMPP的弯曲模量和热变形温度显著增加，结晶温度和结晶速率明显提高，BMPP的拉伸强度也较PP大幅增加；但成核剂对PPc的性能影响不大，而加入纳米CaCO3后则使PPc的力学性能和结晶温度同步显著增加。     

原位聚合制备碳纳米管/PMMA复合材料的研究

采用原位聚合的方法，制备了多壁碳纳米管／聚甲基丙烯酸甲酯复合材料。多壁碳纳米管经过强酸氧化处理。表面具有有机活性。碳纳米管的加入并未使聚合诱导期延长，但令体系粘度增加，自加速现象提早出现。DMA和TGA的研究表明，碳纳米管用量少于1．0％的复合物玻璃化温度降低，分解温度无显著变化。加入1．0％的碳纳米管可以使PMMA复合材料冲击强度提高80％以上。断面扫描电镜表明，碳纳米管呈单管分散于基体中。     

Effects of finish rolling deformation on hydrogen-induced cracking and hydrogen-induced ductility loss of high-vanadium TMCP X80 pipeline steel

An optimum finish rolling deformation (FRD) of thermomechanical controlled processing (TMCP) is suggested to improve the hydrogen-induced ductility loss of high-vanadium X80 pipeline steel in this study. The results demonstrate that with increasing FRD the microstructure refines, the grain size of the steel decreases and the recrystallization degree deepens. The increase of FRD leads to the reduction of low angle grain boundaries (LAGBs) and the grains oriented with plane {100} parallel to normal direction ({100}//ND) fibres, which plays a significant role in improving the resistance of crack propagation. Besides, the differences of effective hydrogen diffusion coefficient and diffusible hydrogen concentration are negligible among four experimental steels with various FRD. However, the best hydrogen-induced ductility loss resistance is obtained in the steel with 40% FRD containing the most nano-scale precipitates acting as effective hydrogen traps.     

纳米金属粉末的应用

介绍了纳米金属粉末在电子、磁性材料、汽车工业、军事工业、粉末冶金等领域中的一些应用前景;简要阐述纳米金属粉末在应用中存在的如易燃、易爆、不易储运、造价高等的实际问题,以及今后的重点研究方向。