Nano-scale Reinforcements and Properties of Al-Si-Cu Alloy Processed by High-Pressure Torsion

To improve the comprehensive mechanical properties of Al-Si-Cu alloy,it was treated by a high-pressure torsion process,and the effect of the deformation degree on the microstructure and properties of the Al-Si-Cu alloy was studied.The results show that the reinforcements(β-Si andθ-CuAl_(2)phases)of the Al-Si-Cu alloy are dispersed in theα-Al matrix phase with finer phase size after the treatment.The processed samples exhibit grain sizes in the submicron or even nanometer range,which effectively improves the mechanical properties of the material.The hardness and strength of the deformed alloy are both significantly raised to 268 HV and 390.04 MPa by 10 turns HPT process,and the fracture morphology shows that the material gradually transits from brittle to plastic before and after deformation.The elements interdiffusion at the interface between the phases has also been effectively enhanced.In addition,it is found that the severe plastic deformation at room temperature induces a ternary eutectic reaction,resulting in the formation of ternary Al+Si+CuAl_(2)eutectic.

Antibacterial Effect of Nano-scale TiO_2 on Parasitic Bacterium of Nanfeng Citrus in Storage Period

[Objective] The aim was to observe the antibacterial effect of nano-scale Titanium dioxide on parasitic bacterium of Nanfeng Citrus in storage period.[Method] Nano-scale Titanium dioxide was prepared by dibutyl phthalate through sol-gel method under anhydrous conditions,and orthogonal experiment was used to determine optimum conditions for nano-scale Titanium dioxide preparation,and structure characterization of nano-scale Titanium dioxide was carried out by X-Ray diffractometer.Oxford cup method was used to explore inhibition effect of nano-scale Titanium dioxide suspension on the activity of normal parasitic bacterium of Nanfeng Citrus.Simultaneously,the empirical preservation test was carried out.[Result] The average diameter of nano-scale Titanium dioxide powder attained to 14.6 nm,actual average yield could reach 90.83% with RSD（Relative Standard Deviation）of 0.86%.[Conclusion] Nano-scale Titanium dioxide had good antibacterial effect on the parasitic bacterium of Nanfeng Citrus in storage period.

Visual Object Tracking and Servoing Control of a Nano-Scale Quadrotor:System,Algorithms,and Experiments

There are two main trends in the development of unmanned aerial vehicle(UAV)technologies:miniaturization and intellectualization,in which realizing object tracking capabilities for a nano-scale UAV is one of the most challenging problems.In this paper,we present a visual object tracking and servoing control system utilizing a tailor-made 38 g nano-scale quadrotor.A lightweight visual module is integrated to enable object tracking capabilities,and a micro positioning deck is mounted to provide accurate pose estimation.In order to be robust against object appearance variations,a novel object tracking algorithm,denoted by RMCTer,is proposed,which integrates a powerful short-term tracking module and an efficient long-term processing module.In particular,the long-term processing module can provide additional object information and modify the short-term tracking model in a timely manner.Furthermore,a positionbased visual servoing control method is proposed for the quadrotor,where an adaptive tracking controller is designed by leveraging backstepping and adaptive techniques.Stable and accurate object tracking is achieved even under disturbances.Experimental results are presented to demonstrate the high accuracy and stability of the whole tracking system.

Numerical Analysis of the Adhesive Forces in Nano-Scale Structure

Nanohairs, which can be found on the epidermis of Tokay gecko＇s toes, contribute to the adhesion by means of van der Waals force, capillary force, etc. This structure has inspired many researchers to fabricate the attachable nano-scale structures. However, the efficiency of artificial nano-scale structures is not reliable sufficiently. Moreover, the mechanical parameters related to the nano-hair attachment are not yet revealed qualitatively. The mechanical parameters which have influence on the ability of adhesive nano-hairs were investigated through numerical simulation in which only van der Waals force was considered. For the numerical analysis, finite element method was utilized and van der Waals force, assumed as 12-6 Lennard-Jones potential, was implemented as the body force term in the finite element formulation.

In-situ hydrocarbon formation and accumulation mechanisms of micro- and nano-scale pore-fracture in Gulong shale, Songliao Basin, NE China

By conducting experimental analyses, including thermal pyrolysis, micro-/nano-CT, argon-ion polishing field emission scanning electron microscopy (FE-SEM), confocal laser scanning microscopy (CLSM), and two-dimensional nuclear magnetic resonance (2D NMR), the Gulong shale oil in the Songliao Basin was investigated with respect to formation model, pore structure and accumulation mechanism. First, in the Gulong shale, there are a large number of pico-algae, nano-algae and dinoflagellates, which were formed in brackish water environment and constituted the hydrogen-rich oil source materials of shale. Second, most of the oil-generating materials of the Qingshankou Formation shale exist in the form of organo-clay complex. During organic matter thermal evolution, clay minerals had double effects of suppression and catalytic hydrogenation, which expanded shale oil window and increased light hydrocarbon yield. Third, the formation of storage space in the Gulong Shale was related to dissolution and hydrocarbon generation. With the diagenesis, micro-/nano-pores increased, pore diameter decreased and more bedding fractures appeared, which jointly gave rise to the unique reservoir with dual media (i.e. nano-scale pores and micro-scale bedding fractures) in the Gulong shale. Fourth, the micro-/nano-scale oil storage unit in the Gulong shale exhibits independent oil/gas occurrence phase, and shows that all-size pores contain oils, which occur in condensate state in micropores or in oil-gas two phase (or liquid) state in macropores/mesopores. The understanding about Gulong shale oil formation and accumulation mechanism has theoretical and practical significance for advancing continental shale oil exploration in China.

Nano-scale Interfacial Friction Behavior between Two Kinds of Materials in MEMS Based on Molecular Dynamics Simulations

The aim of this article was to provide a systematic method to perform molecular dynamics simulotion or evaluation for nano-scale interfacial friction behavior between two kinds of materials in MEMS design. Friction is an important factor affecting the performance and reliability of MEMS. The model of the nano-scale interracial friction behavior between two kinds of materials was presented based on the Newton＇ s equations of motion. The Morse potential function was selected for the model. The improved Verlet algorithm was employed to resolve the model, the atom trajectories and the law of the interfacial friction behavior. Comparisons with experimental data in other paper confirm the validity of the model. Using the model it is possible to simulate or evaluate the importance of different factors for designing of the nano-scale interfacial friction behavior between two kinds of materials in MEMS.

Influence of the finite size effect of Si（001）/SiO2 interface on the gate leakage current in nano-scale transistors

With the device size gradually approaching the physical limit, the small changes of the Si(001)/SiO 2 interface in silicon-based devices may have a great impact on the device characteristics. Based on this, the bridge-oxygen model is used to construct the interface of different sizes, and the finite size effect of the interface between fine electronic structure silicon and silicon dioxide is studied. Then, the influence of the finite size effect on the electrical properties of nanotransistors is calculated by using the first principle. Theoretical calculation results demonstrate that the bond length of Si-Si and Si-O shows a saturate tendency when the size increases, while the absorption capacity of visible light and the barrier of the interface increase with the decrease of size. Finally, the results of two tunneling current models show that the finite size effect of Si(001)/SiO 2 interface can lead to a larger change in the gate leakage current of nano-scale devices, and the transition region and image potential, which play an important role in the calculation of interface characteristics of large-scale devices, show different sensitivities to the finite size effect. Therefore, the finite size effect of the interface on the gate leakage current cannot be ignored in nano-scale devices.

Novel Nano-scale Overlay Alignment Method for Room-temperature Imprint Lithography

A novel nano-scale alignment technique based on Moiré signal for room-temperature imprint lithography in the submicron realm is proposed. The Moiré signals generated by a pair of quadruple gratings on two templates respectively are optically projected onto a photodetector array, then the detected Moiré signals are used to estimate the alignment errors in x and y directions. The experiment result indicates that complex differential Moiré signal is sensitive to relative displacement of the pair of marks than each single Moiré signal, and the alignment resolutions obtained in x and y directions are ±20nm(3σ) and ±24nm(3σ). They can meet the requirement of alignment accuracy for submicron imprint lithography.

一种新的元素迁移形式及其地球化学环境效应

提出了地壳中存在一种新的元素迁移现象 ,即由于地壳内存在的上升气流将非气态元素以纳米微粒形式垂直迁移至地表 ,迁移距离可达几百米 ,甚至几千米。通过室内模型实验证明 ,元素纳米微粒以上升气流垂向迁移形式为主 ,扩散迁移只占极小部分。列举了宣汉气田及成都平原隐伏断裂上汞污染的二个实例 ,初步讨论这种新的元素迁移现象对地表地球化学环境的影响。

纳米级RDX颗粒的制备

利用高速撞击法研究了纳米级黑索今(RDX)的制备。结果表明:采用高速撞击法可制备出粒度分布较窄的纳米级RDX颗粒,其粒径d50可细化到46.7 nm左右,其颗粒度分布宽度在0.6 nm范围内。

大气带电粒子对电磁波的散射研究

研究大气中带电粒子对电磁波的散射特性,对利用遥感方法雷达探测云层、雷电预警、分析沙尘对电磁波传播的影响等具有重要意义。从宏观和微观两个方面分析了瑞利散射条件下大气粒子带电对电磁波散射的影响。宏观和微观分别反映了电磁波散射的两种机制,分别对应的是受电场作用后电荷运动形成宏观电流对电磁波的散射,以及单个电荷(电子)受电场作用后在平衡位置附近振动而引起的电磁散射。通过对比中性粒子和所带电荷对电磁波的散射截面量级,分析了大气粒子带电后对电磁波散射的影响。研究表明:宏观上粒子所带电荷对电磁波的散射没有影响,而微观上,在某些频率附近,粒子所带电荷会对电磁波的散射产生较大影响。

宇宙早期粒子与现时粒子的质量、半径和电磁特性

引入宇宙早期核子概念,讨论了它与现时核子的质量、半径间存在的差别.多成份宇宙中的其它粒子e、νe、γ,也同样存在这种差别.据此计算了三代轻子的"反常质量"与"反常磁矩".现时轻子的"反常磁矩"反映了轻子存在亚结构的可观测效应,宇宙早期轻子的"反常磁矩"被大削弱,可视为类点粒子.

HPLC测定益肝颗粒中五味子甲素的质量浓度

建立测定益肝颗粒中五味子甲素质量浓度的方法.室温条件下超声提取五味子甲素,HPLC测定其质量浓度,SinoChrom ODS-BP色谱柱,以甲醇-水(87∶13)为流动相;检测波长为254 nm;柱温25℃;流速为1.0 mL/min;进样量10μL.五味子甲素进样量在0.2～1.0μg范围内与峰面积线性关系良好;结果平均加样回收率为98.82%,(n=3),RSD为1.19%.该方法灵敏、准确、重复性好,可用于益肝颗粒的质量控制.

流态化CVD制备超细Al_2O_3－SnO_2复合粒子过程模型研究

基于流态化ＣＶＤ制备超细复合粒子过程中的反应、成核、包敷、气流夹带，建立了流态化ＣＶＤ反应器中描述超细粒子的粒度、分布及成核包敷、成膜包敷的一维过程模型。针对ＳｎＣｌ＿４－Ｈ＿２Ｏ－Ｎ＿２体系包敷超细Ａｌ＿２Ｏ＿３粒子的过程，研究了反应器中ＳｎＯ＿２粒子的形成过程及操作参数对其在Ａｌ＿２Ｏ＿３粒子表面的淀积速率及形态的影响。结果表明，反应温度和ＳｎＣｌ＿４浓度升高，包敷速率加快，包敷形态变差；背景气氛粘度增大，包敷形态变优，包敷速率减小；操作气速增大，包敷速率加快，包敷形态变优。

高速电弧喷涂涂层的性能

分析了高速电弧涂层的结合强度、涂层显微硬度以及涂层孔隙率 ,并与普通电弧喷涂涂层对比 ,证明喷涂粒子飞行速度的提高 。

2A12铝合金纳米复合微弧氧化陶瓷层摩擦学性能研究

研究2A12铝合金表面制备含纳米Si（）2颗粒复合微弧氧化陶瓷层，主要考察了不同尺度、不同类型纳米颗粒对陶瓷层摩擦学性能的影响规律。采用扫描电镜观察涂层表面形貌，CETR微米摩擦磨损试验机和白光干涉仪考察复合陶瓷涂层的耐磨性。结果表明，与未添加纳米颗粒的普通微弧氧化层相比，添加20nmSi02、80nmSi02、800nmSiO2后所形成的陶瓷涂层孔隙尺寸和数量均明显减小，并具有较高的耐磨性。

光流子(流线)的量子理论

本文在光线量子力学的基础上,提出光在介质中传输的流线结构模型,引进光流子的概念,揭示出受介质限制的传输光场是一束流线结构图象,推导出光流子的量子方程,重新定义一些概念,初步形成了光流子(或流线)的量子理论。

316L Austenite Stainless Steels Strengthened by Means of Nano-scale Twins

By means of dynamic plastic deformation （DPD） followed by thermal annealing, a mixed structure of micro-sized austenite grains embedded with nano-scale twin bundles （of about 20% in volume） has been synthesized in a 316L stainless steel （SS）. Such a 316L SS sample exhibits a tensile strength as high as 1001 MPa and an elongation-to-failure of about 23%. The much elevated strength originates from the presence of a considerable number of strengthening nano-twin bundles, while the ductility from the recrystallized grains. The superior strength-ductility combination achieved in the nano-twins-strengthened austenite steel demonstrates a novel approach for optimizing the mechanical properties in engineering materials.

Wetting Characteristics of Insect Wing Surfaces

Biological tiny structures have been observed on many kinds of surfaces such as lotus leaves,which have an effect on the coloration of Morpho butterflies and enhance the hydrophobicity of natural surfaces.We investigated the micro-scale and nano-scale structures on the wing surfaces of insects and found that the hierarchical multiple roughness structures help in enhancing the hydrophobicity.After examining 10 orders and 24 species of flying Pterygotan insects,we found that micro-scale and nano-scale structures typically exist on both the upper and lower wing surfaces of flying insects.The tiny structures such as denticle or setae on the insect wings enhance the hydrophobicity,thereby enabling the wings to be cleaned more easily.And the hydrophobic insect wings undergo a transition from Cassie to Wenzel states at pitch/size ratio of about 20.In order to examine the wetting characteristics on a rough surface,a biomimetic surface with micro-scale pillars is fabricated on a silicon wafer, which exhibits the same behavior as the insect wing,with the Cassie-Wenzel transition occurring consistently around a pitch/width value of 20.

Preparation and Structural Investigation of CuCl_2 Graphite Intercalation Compounds

Superfine graphite powder was prepared by ball-milling exfoliated graphite containing anhydrous CuCl2 in planetary ball milling systems. Nano-scale CuCl2 graphite intercalation compounds were synthesized by heating a mixture of anhydrous CuCl2 and graphite nanosheets. Scanning electron microscopy, energy-dispersive X-ray spectroscopy and high-resolution transmission electron microscopy were performed to characterize the microstructures of stage-1 nano-scale CuCl2 graphite intercalation compounds. The structure and components of the domain wall and core in the nano-scale CuCl2 graphite intercalation compounds are described. The results show that the content of CuCl2 in the mixture plays a crucial role in the size of the nano-scale CuCl2 graphite intercalation compound.