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

Gold (a) and at least one metal (b) which is Zr, Nb, and/or Hf, are deposited on the substrate, followed by heating at 200-500 degrees C., pref. for 1-100 h, to form a cpd. (a,b). Masking and selective removal of the cpd. (a,b) is then used to form the conductor strip. The pref. substrate is suitable for mfg. magnetic bubble memories. Deposition pref. occurs in a vacuum harder than 10-5 torr total pressure in the absence of oxygen; or via cathodic sputtering in inert gas using high frequency of 500-2000 V and d.c. bias of 0-200 V. The strip pref. uses a bottom and top layer of cpd. (a,b), with a middle layer of gold. The min. dimension of the strip is pref. below 0.015 mm. Method is used to minimise electromigration on silicon semiconductor substrates carrying integrated circuits, and on garnet substrate for bubble memories.

Method of production of thin conducting metal strips on semiconductor substrates and strips produced by this method

Stress relaxation behavior of thermally induced stresses in passivated line structures is strongly influenced by the metal yield strength. For some line geometries, stress relaxation can lead to void formation. In this study, bending beam measurements have been carried out to measure the thermal stress and stress relaxation behavior of passivated Al(1 wt.% Cu) line structures with 3, 1, and 0.5 fim line widths. Our results reveal that stress relaxation in Al(Cu) films and lines shows Iog(time) kinetics consistent with a thermally activated dislocation glide mechanism. The kinetics of stress relaxation depend on line geometry and temperature, which can be explained by a combined effect of temperature (mass transport) and shear stress (driving force).

Line width dependence of stress relaxation and yield behavior of passivated Al(Cu) lines

Preclean is a critical process step in Cu metallization to ensure device reliability. For the integration of ultra low k (kles2.5) dielectrics, an advanced preclean (APC) technology has been developed and characterized using PECVD SiOCH (k=2.5) dielectrics. With the optimal hardware and process, this technology minimizes plasma damage, causing no measurable k increase and having the lowest impact to other properties of the low k film. At the same time it effectively removes etch residues in dielectric structures and native oxides on the underneath metal surface prior to Cu barrier deposition. The electrical tests demonstrated that APC not only met the reliability requirements for typical BEOL structures but also significantly reduced line-to-line capacitance degradation over ultra low k structures, offering a superior alternative to the conventional preclean technologies

Advanced Preclean for Integration of PECVD SiOCH (k=2.5) Dielectrics with Copper Metallization Beyond 45nm Technology

A plasma altered layer model was developed to characterize plasma damage in porous OSG (organosilicate glass) low-k dielectrics by taking into account the kinetics of radical diffusion, reaction, and recombination. A gap structure was designed to study plasma damage and validate the model. It consisted of two parallel rectangular Si spacers and a top optical mask to control the energy and intensity of ion, photon, and radical in the plasma. CO 2 and O 2 plasma-induced damages were found to depend on the radical concentration, the energy and intensity of VUV photons, the ion energy, and the substrate temperature. Overall, the results obtained from plasma damage studies were consistent with the prediction of the model. The application of the model was demonstrated in a study of He plasma pretreatment and damage formation in OSG films with varying carbon concentrations. Both treatments were found to be effective in improving the material resistance to plasma damage.

Plasma altered layer model for plasma damage characterization of porous OSG films

Stress‐induced void formation (SIV) was studied in dual damascene Cu/oxide and Cu/low k interconnects over a temperature range of 140 ∼ 350 °C. Two modes of stressmigration were observed depending on the baking temperature and sample geometry. At lower temperatures (T 290 °C), voids were found in via bottoms which were connected to wide lines. The rate of high temperature stressmigration increased exponentially with temperature up to 350 °C, which was the temperature limit of the test system, and did not show a peak at an intermediate temperature. The activation energy was 1.0 eV for Cu/oxide, 0.86 eV for Cu/OSG, and ∼1.0 eV for Cu/FSG interconnects. The dependence of stressmigration on linewidth, sample geometry, and ILD material was presented in this paper.

Paul S. Ho

Papers

Method of production of thin conducting metal strips on semiconductor substrates and strips produced by this method

Line width dependence of stress relaxation and yield behavior of passivated Al(Cu) lines

Advanced Preclean for Integration of PECVD SiOCH (k=2.5) Dielectrics with Copper Metallization Beyond 45nm Technology

Plasma altered layer model for plasma damage characterization of porous OSG films

Stressmigration studies on dual damascene Cu/oxide and Cu/low k interconnects