抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications as protective coatings in areas, such as magnetic storage disks, optical windows and micro-electromechanical devices (MEMs).

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Diamond-like amorphous carbon

Rapid progress in the synthesis and processing of materials with structure on nanometer length scales has created a demand for greater scientific understanding of thermal transport in nanoscale devices, individual nanostructures, and nanostructured materials. This review emphasizes developments in experiment, theory, and computation that have occurred in the past ten years and summarizes the present status of the field. Interfaces between materials become increasingly important on small length scales. The thermal conductance of many solid–solid interfaces have been studied experimentally but the range of observed interface properties is much smaller than predicted by simple theory. Classical molecular dynamics simulations are emerging as a powerful tool for calculations of thermal conductance and phonon scattering, and may provide for a lively interplay of experiment and theory in the near term. Fundamental issues remain concerning the correct definitions of temperature in nonequilibrium nanoscale systems. Modern Si microelectronics are now firmly in the nanoscale regime—experiments have demonstrated that the close proximity of interfaces and the extremely small volume of heat dissipation strongly modifies thermal transport, thereby aggravating problems of thermal management. Microelectronic devices are too large to yield to atomic-level simulation in the foreseeable future and, therefore, calculations of thermal transport must rely on solutions of the Boltzmann transport equation; microscopic phonon scattering rates needed for predictive models are, even for Si, poorly known. Low-dimensional nanostructures, such as carbon nanotubes, are predicted to have novel transport properties; the first quantitative experiments of the thermal conductivity of nanotubes have recently been achieved using microfabricated measurement systems. Nanoscale porosity decreases the permittivity of amorphous dielectrics but porosity also strongly decreases the thermal conductivity. The promise of improved thermoelectric materials and problems of thermal management of optoelectronic devices have stimulated extensive studies of semiconductor superlattices; agreement between experiment and theory is generally poor. Advances in measurement methods, e.g., the 3ω method, time-domain thermoreflectance, sources of coherent phonons, microfabricated test structures, and the scanning thermal microscope, are enabling new capabilities for nanoscale thermal metrology.

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Nanoscale thermal transport

This paper investigated the plasma ashing damage to patterned porous low k structures with the objective to minimize the plasma damage by optimizing the low-k structural geometry and plasma chemistry. We first extended the plasma altered layer model to formulate the transport kinetics of the plasma process in patterned low-k structures. This enabled us to analyze the effects of the hardmask thickness, trench width and trench length on the plasma interaction with the trench sidewall. Then CO/O 2 and CO 2 /N 2 plasmas were used to replace O 2 plasma for ashing process to examine their potential for reducing plasma ashing damage to porous low k patterned structures. With increasing CO in CO/O 2 plasma, the extent of plasma induced damages was found to decrease. Similarly, with increasing N 2 in CO 2 /N 2 plasma, the plasma induced damages were also found to decrease. On the basis of the Knudsen diffusivity difference among C, N, and O, the reduction of plasma induced damage was ascribed to the formation of C- and N- rich passivation layer on the sidewall and pore surface of the patterned low-k structure.

Minimization of plasma ashing damage to OSG low-k dielectrics

In this paper, we investigate the microstructure evolution in Cu, Co and Ru nanointerconnects and the scaling effect on resistivity. The scaling effect on microstructure of Cu interconnects was analyzed to the 24 nm linewidth for the 14 nm node using a high-resolution TEM precession microdiffraction technique. The TEM study was supplemented by a Monte Carlo simulation to investigate grain growth in nanointerconnects based on local energy minimization. The scaling effect on electrical resistivity was analyzed for Cu, Ru and Co nanointerconnects, taking into account the contributions from surface and grain boundary scatterings. The results for Cu and Co are consistent with recent experiments.

Microstructure Evolution and Effect on Resistivity for Cu Nanointerconnects and Beyond

A recently developed precession electron diffraction (PED) technique in transmission electron microscopy (TEM) was employed to characterize the grain orientation and grain boundaries for Cu interconnects of the 45 nm node. The results showed a strong &#60;111gt; and &#60;110gt; textures along the width and the thickness of the line, respectively and a low fraction of coherent twin boundaries. The microstructure characteristics were applied to evaluate the grain structure effect on electromigration (EM) reliability. We first extracted the interfacial diffusivity components for (111), (110), and (100) surfaces and the averaged grain boundary diffusivity by analyzing the resistance traces observed in EM tests. Then the flux divergence at the triple points of grain boundary intersecting the interface was calculated to identify potential voiding sites. Similar analysis was extended to via/line regions to evaluate the flux divergence for slit void formation and to assess the probability of EM early failure.

Grain structure analysis and implications on electromigration reliability for Cu interconnects

The 13 papers in this special section focus on materials, processing, and reliability of 3-D interconnects.

Forward to the Special Section on “Materials, Processing, and Reliability of 3-D Interconnects”

The present paper discusses the four-point bending technique employed at The University of Texas at Austin (UT Austin) to characterize adhesion strength of ultra low-k dielectric materials to CVD barrier layers. Adhesion energy between an ultra low-k dielectric material and a barrier layer was measured as a function of porosity (2.0 < k < 2.3). It was found that the fracture energy decreases with the dielectric constant, which correlates with mechanical properties such as Young’s modulus and hardness. Adhesion measurement data was also obtained for different lowk / barrier layer interfaces. The independence of interfacial fracture energy on the type of interface suggests that cohesive failure occurs in the low-k material layer and not at the interface. In addition, the very low fracture energies (G < 3 J/2) confirm the weak mechanical properties of such highly porous materials. Experimental results are illustrated with analysis of failure surfaces using Auger Electron Spectroscopy and Scanning Electron Microscopy.

Paul S. Ho

Papers

Minimization of plasma ashing damage to OSG low-k dielectrics

Microstructure Evolution and Effect on Resistivity for Cu Nanointerconnects and Beyond

Grain structure analysis and implications on electromigration reliability for Cu interconnects

Forward to the Special Section on “Materials, Processing, and Reliability of 3-D Interconnects”

Interfacial Adhesion Study of Porous Low-K Dielectrics to CVD Barrier Layers