PLASMA IMMERSION ION IMPLANTER FOR THE MODIFICATION OF INDUSTRIAL AEROSPACE COMPONENTS

1　IntroductionPlasmaimmersionionimplantation (PIII) ,initiallydevelopedbyConradetalin 1 987,hase mergedasaviablealternativetoconventionalbeam lineionimplantationformetallurgicalappli cationsduetoitsconformalimplantationcapabili ty ,highthroughput,andcost effectiveness[1～ 6] .Asaresult,muchprogresshasbeenmadeinPIIIhardwareandunderstandingofplasmaphysicsper tainingtoindustrialapplications[7～ 10 ] .Inspiteofpromisingresults,thethintreatedlayer,complex ityofthePIIIprocess ,anddifficultyofi…     

A Parametrization of Isometric Immersions between Hyperbolic Spaces

We parametrize the space of isometric immersions of the hyperbolic n -space into the hyperbolic ( n +1)-space by a family of properly chosen (at most) countable n -tuples of real-valued functions. This is an answer to the problem posed by Nomizu in 1973. We also construct a one-parameter family of deformable isometric immersions from the quotient spaces of the hyperbolic 2-plane modulo and some totally discontinuous subgroups of isometries.     

-principles for hypersurfaces with prescribed principle curvatures and directions

We prove that any compact orientable hypersurface with boundary immersed (resp. embedded) in Euclidean space is regularly homotopic (resp. isotopic) to a hypersurface with principal directions which may have any prescribed homotopy type, and principal curvatures each of which may be prescribed to within an arbitrary small error of any constant. Further we construct regular homotopies (resp. isotopies) which control the principal curvatures and directions of hypersurfaces in a variety of ways. These results, which we prove by holonomic approximation, establish some h-principles in the sense of Gromov, and generalize theorems of Gluck and Pan on embedding and knotting of positively curved surfaces in 3-space.

     

一种自支撑金纳米薄膜的制备、结构和氮吸附特性

以一种新的硅微米/纳米结构复合体系——硅纳米孔柱阵列作为还原性衬底，采用浸渍技术制备出一种自支撑的金纳米薄膜，并对其表面形貌和结构进行了表征.实验表明，金纳米薄膜的制备过程是一个自终止过程.当硅纳米孔柱阵列被耗尽后，浸渍溶液中Au³⁺的还原反应将自行终止；同时，所形成的金纳米薄膜自动与衬底脱离并成为一种自支撑薄膜.薄膜的形成机理被归因于硅纳米孔柱阵列所具有的高的表面活性和还原性.用能量弥散x射线谱对薄膜表面化学成分分析的结果表明，如此制备的金纳米薄膜具有很强的氮吸附和氮储存能力.这一特性有可能在气体传感器、空气分离和氮纯化以及氮化合物的膜合成器等技术领域得到应用. 关键词： 自支撑金纳米薄膜 硅纳米孔柱阵列 浸渍技术     

Some slant submanifolds of <Emphasis Type="Italic">S</Emphasis>-manifolds

Summary We study some special types of slant submanifolds of S-manifolds related to the second fundamental form of the immersion: totally f-geodesic and f-umbilical, pseudo-umbilical and austere submanifolds. We also give several examples of such submanifolds.     

R~(2+p)中浸入曲面的共形G形变

对于Riemann曲面M到欧氏空间R+p的共形浸入f,本文引入了其伴随形式的概念;利用伴随形式和法丛的联络,我们建立了f是Gj-可形变的充分必要条件.主要结论如下:(1)如果f是G*-可形变的,则f具有平坦的法丛和闭的伴随形式;(2)当M是单连通时,如果f具有平坦的法丛和闭的伴随形式,则f是G*-可形变的.     

The role of grain boundaries in the mechanism of plasma immersion hydrogenation of nanocrystalline magnesium films

In this paper, attention in focused on the nanostructured magnesium films for hydrogen storage. It is shown that 2 μm thick Mg film is transformed into MgH₂ film under high-flux and fluence hydrogen plasma immersion ion implantation at 450 K for 15 min. All hydrogen desorbs at temperature about 530 K, which corresponds to the decomposition of MgH₂ → Mg + H₂↑. The macroscopic and microscopic observations show that magnesium film undergoes a high deformation and restructuring during hydrogenation-dehydrogenation reaction. The suggested hydrogenation model is based upon the incorporation of excess of hydrogen atoms in grain boundaries of nanocrystalline Mg film driven by the increase in surface chemical potential associated with the implantation flux. The results provide new aspects of hydriding of thin nanocrystalline film materials under highly non-equalibrium conditions on the surface.     

Investigation of Optics in the 10–200μm Size Regime

Optical components and systems with dimensions between 10 and 200 mm are discussed with specific examples of testing, simulation, and assembly methods. This size regime, which is conventionally classified with micro-optics, offers attractive possibilities for next-generation micro-optics packaging. However, optics in this regime suffer from few available testing and simulation tools. Several theoretical application examples are described, including a high-index solid immersion lens and a pickup for optical data storage. Challenges and solutions for design and simulation, testing, and assembly of such systems are also discussed.     

近场高密度光存储

文章综述了近场高密度光存储领域的研究进展情况，着重介绍了固体浸没透镜（solid immersion lens,SIL)存储方案和近场超分辨结构（super resolution near-field,SuperRENS)的原理、研究进展及问题。     

浸没透镜

本文简述了浸没透镜探测器光学系统的独特作用,并对其在设计、加工工艺中应注意的问题进行了分析说明。