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).

/pdf/diamond-like-amorphous-carbon-3pczopr0z7.pdf

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.

/pdf/nanoscale-thermal-transport-1frv881kzm.pdf

Nanoscale thermal transport

As the minimum features in semiconductor devices decrease, it is a new trend to incorporate copper and polymers with dielectric constant less than 3.0 to enhance the performance of the devices. Two fluorinated polymers, poly(biphenyl perfluorocyclobutyl ether) (BPFCB) and poly(1,1,1-triphenyl ethane perfluorocyclobutyl ether) (PFCB), are newly developed polymers with dielectric constants below 3.0. These two polymers have a similar backbone structure, but PFCB has the capability of crosslinking. To know the implications of these two polymers in the semiconductor industry, properties that are important for the integral reliability of Integral Circuits (IC), such as thermal and mechanical properties, should be understood. This comparative study shows that the crosslinking in perfluorocyclobutane aromatic ether polymer can reduce vertical thermal expansion and increase glass transition temperature (T g ) while water absorption, crystalline-like phase, and dielectric constant are slightly increased.

The effect of crosslinking on thermal and mechanical properties of perfluorocyclobutane aromatic ether polymers

The Ag-alloy films have been investigated as source/drain materials applicable to thin-film transistor liquid-crystal displays (TFT-LCDs). The Ag-alloy consisting of 0.9at.%Pd, 1.7at.%Cu (designated APC) showed a resistivity that was lower than one-half that of AlNd. It also had good contact characteristics with amorphous Si (a-Si). In addition, the Ag/Si was stable after heating to above 700°C, requiring no diffusion barrier to prevent reaction between Ag and Si. Pure Ag films deposited on glass by DC magnetron sputtering showed severe hillock formation, hole growth, and agglomeration upon annealing in air. In comparison, the APC-alloy film exhibited improved resistance to agglomeration. Further, inverted-staggered back-channel-etch hydrogenated amorphous silicon (a-Si:H) TFTs using an APC-alloy film as a source/drain material had a threshold voltage of 4 V. A structure of single layers of gate-APC alloys and source/drain-APC alloys leads to lower costs and productivity improvements of large-area, high-resolution, active-matrix LCDs, such as 40-in. size panels through process simplification.

Feasibility of an Ag-alloy film as a thin-film transistor liquid-crystal display source/drain material

In 3‐D interconnect structures, process‐induced thermal stresses around through silicon vias (TSVs) raise serious reliability issues such as silicon cracking and performance degradation of devices. In this study, the thermo‐mechanical reliability of 3‐D interconnect was investigated using finite element analysis (FEA) combined with analytical methods. The thermal stress in silicon was found to decrease as a function of distance from an isolated TSV but increase with the TSV diameter. Additional simulation results demonstrated that hybrid TSV structures can significantly reduce thermal stresses. An analytical solution was introduced to deduce the stress distribution around an isolated TSV, which was applied to deduce the stress interaction in TSV arrays based on linear superposition of the analytical solution. The stress interaction is directional dependent, thus the TSV array configuration can be optimized to improve the keep‐away‐zone design for stress‐sensitive devices.

/pdf/thermal-stresses-analysis-of-3-d-interconnect-1cmaca9hg2.pdf

Thermal Stresses Analysis of 3‐D Interconnect

Thermal stresses of Cu line structures of 0.4 and 0.2 /spl mu/m linewidth integrated with fluorinated silicon oxide SiOF and two kinds of low k dielectrics, carbon doped oxide CDO and organic polymer SiLK/spl trade/, were measured using x-ray diffraction. Finite element analysis was performed to evaluate the stress behavior of the Cu lines and to examine the effect of scaling in linewidth. After verification with the measured Cu line stresses, FEA was extended to evaluate the stress behavior of the low k dielectrics. The confinement effects on thermal stresses due to low k dielectric on Cu lines and Cu lines on the dielectric are compared and discussed.

Paul S. Ho

Papers

The effect of crosslinking on thermal and mechanical properties of perfluorocyclobutane aromatic ether polymers

Feasibility of an Ag-alloy film as a thin-film transistor liquid-crystal display source/drain material

Thermal Stresses Analysis of 3‐D Interconnect

Effects of dielectric material and linewidth on thermal stresses of Cu line structures

Study of out-of-plane elastic properties of PMDA-ODA and BPDA-PDA polyimide thin films