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

Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm complementary metal–oxide–semiconductor (CMOS) technology. A systematic consideration of the required properties of gate dielectrics indicates that the key guidelines for selecting an alternative gate dielectric are (a) permittivity, band gap, and band alignment to silicon, (b) thermodynamic stability, (c) film morphology, (d) interface quality, (e) compatibility with the current or expected materials to be used in processing for CMOS devices, (f) process compatibility, and (g) reliability. Many dielectrics appear favorable in some of these areas, but very few materials are promising with respect to all of these guidelines. A review of current work and literature in the area of alternate gate dielectrics is given. Based on reported results and fundamental considerations, the pseudobinary materials systems offer large flexibility and show the most promise toward success...

/pdf/high-k-gate-dielectrics-current-status-and-materials-zjvba0c4u8.pdf

High-κ gate dielectrics: Current status and materials properties considerations

There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

Coinage metals, such as Au, Ag, and Cu, have been important materials throughout history.1 While in ancient cultures they were admired primarily for their ability to reflect light, their applications have become far more sophisticated with our increased understanding and control of the atomic world. Today, these metals are widely used in electronics, catalysis, and as structural materials, but when they are fashioned into structures with nanometer-sized dimensions, they also become enablers for a completely different set of applications that involve light. These new applications go far beyond merely reflecting light, and have renewed our interest in maneuvering the interactions between metals and light in a field known as plasmonics.2–6

In plasmonics, the metal nanostructures can serve as antennas to convert light into localized electric fields (E-fields) or as waveguides to route light to desired locations with nanometer precision. These applications are made possible through a strong interaction between incident light and free electrons in the nanostructures. With a tight control over the nanostructures in terms of size and shape, light can be effectively manipulated and controlled with unprecedented accuracy.3,7 While many new technologies stand to be realized from plasmonics, with notable examples including superlenses,8 invisible cloaks,9 and quantum computing,10,11 conventional technologies like microprocessors and photovoltaic devices could also be made significantly faster and more efficient with the integration of plasmonic nanostructures.12–15 Of the metals, Ag has probably played the most important role in the development of plasmonics, and its unique properties make it well-suited for most of the next-generation plasmonic technologies.16–18

1.1. What is Plasmonics?
Plasmonics is related to the localization, guiding, and manipulation of electromagnetic waves beyond the diffraction limit and down to the nanometer length scale.4,6 The key component of plasmonics is a metal, because it supports surface plasmon polariton modes (indicated as surface plasmons or SPs throughout this review), which are electromagnetic waves coupled to the collective oscillations of free electrons in the metal.

While there are a rich variety of plasmonic metal nanostructures, they can be differentiated based on the plasmonic modes they support: localized surface plasmons (LSPs) or propagating surface plasmons (PSPs).5,19 In LSPs, the time-varying electric field associated with the light (Eo) exerts a force on the gas of negatively charged electrons in the conduction band of the metal and drives them to oscillate collectively. At a certain excitation frequency (w), this oscillation will be in resonance with the incident light, resulting in a strong oscillation of the surface electrons, commonly known as a localized surface plasmon resonance (LSPR) mode.20 This phenomenon is illustrated in Figure 1A. Structures that support LSPRs experience a uniform Eo when excited by light as their dimensions are much smaller than the wavelength of the light.



Figure 1

Schematic illustration of the two types of plasmonic nanostructures discussed in this article as excited by the electric field (Eo) of incident light with wavevector (k). In (A) the nanostructure is smaller than the wavelength of light and the free electrons ...



In contrast, PSPs are supported by structures that have at least one dimension that approaches the excitation wavelength, as shown in Figure 1B.4 In this case, the Eo is not uniform across the structure and other effects must be considered. In such a structure, like a nanowire for example, SPs propagate back and forth between the ends of the structure. This can be described as a Fabry-Perot resonator with resonance condition l=nλsp, where l is the length of the nanowire, n is an integer, and λsp is the wavelength of the PSP mode.21,22 Reflection from the ends of the structure must also be considered, which can change the phase and resonant length. Propagation lengths can be in the tens of micrometers (for nanowires) and the PSP waves can be manipulated by controlling the geometrical parameters of the structure.23

/pdf/controlling-the-synthesis-and-assembly-of-silver-1ktlgomyt6.pdf

Controlling the synthesis and assembly of silver nanostructures for plasmonic applications

The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.

/pdf/present-and-future-of-surface-enhanced-raman-scattering-34aqgcm385.pdf

Present and Future of Surface-Enhanced Raman Scattering

In this work, the physical and electrical properties of TaSi,N, films are evaluated for gate electrode applications. MOS capacitors with TaSixNy gates of varying N concentrations were fabricated. The stability of TaSixNy/Si02/p-type Si stacks was studied at annealing temperatures of 700"C, 900"C, and 1000°C in Ar. When the nitrogen content exceeds 35 at.%, excellent stability of oxide thickness and gate current is observed for anneals up to 1000°C. The results also indicate that the workfunction of TaSi,N, is compatible with NMOS devices.

http://www.vlsisymposium.org/Past/01web/technology/tec_pdf/T5Ap2.pdf

Electrical Characteristics of TaSi,N,, Gate Electrodes For Dual Gate Si-CMOS Devices

Properties of SiO2 gate dielectric deposited by atomic layer deposition (ALD) on Si-face of 4H silicon carbide (SiC) were systematically studied. The interface state and effective fixed charge densities of ALD SiO2 on n-type 4H–SiC with various post deposition anneal (PDA) conditions were evaluated. It has been found that nitrous oxide (N2O) PDA not only reduces the effective fixed charge density, which includes the fixed oxide charge and charged interface states, at SiC/SiO2 interface but also decreases the gate leakage current. Negative effective fixed charge is observed at SiC/ALD SiO2 interface after N2O PDA. ALD SiO2-based lateral n-channel MOSFETs show high threshold voltage with the promising field-effect mobility and the peak field-effect mobility increases with N2O PDA temperature.

Electrical Characteristics of SiO 2 Deposited by Atomic Layer Deposition on 4H–SiC After Nitrous Oxide Anneal

The role of La2O3 capping in the VT/VFB shift with various high- k and metal gate electrodes was systematically investigated. It was found that the La concentration at the high-k/SiO2 interface is mainly responsible for the VT/VFB modulation in NMOS devices, whereas the effect of the host high-k and gate electrodes on VT/VFB is minimal. A 400-mV shift in VT from the control HfO2 device with minimal degradation in mobility was obtained when a La2O3 layer was inserted between the high-k and SiO2 layers. It was also found that the incorporation of La2O3 in the dielectric stack improves device reliability in terms of breakdown and positive-bias temperature instability characteristics. The main key for the VFB shift is the ability of La diffusion through the host high-k material.

Investigation of the Origin of $V_{T}/V_{\rm FB}$ Modulation by $\hbox{La}_{2}\hbox{O}_{3}$ Capping Layer Approaches for NMOS Application: Role of La Diffusion, Effect of Host High- $k$ Layer, and Interface Properties

Uniform arrays of nano-scale electrolyte-molecule-silicon capacitors have been successfully fabricated. This was done by a combination of reactive ion etch and a selective wet etch through an anodic aluminium oxide mask to form nano-holes in silicon oxide/silicon nitride insulator layers on silicon. Self-assembled monolayers of 4-ferrocenylbenzyl alcohol were then attached to the exposed silicon surfaces at the bottom of the nano-holes. Characterization by conventional capacitance and conductance techniques showed very high capacitance and conductance peaks near -0.6 V, that were attributed to the charging and discharging of electrons into and from discrete levels in the monolayer owing to the presence of the redox-active ferrocenes.

https://iopscience.iop.org/article/10.1088/0957-4484/16/2/013/pdf

Redox-active monolayers on nano-scale silicon electrodes.

The present invention provides microelectronic electrochemical structures and related fabrication methods. A composite microelectronic structure is provided that includes first and second conductors dielectrically isolated from one another at a crossing thereof, the crossing surrounded by a dielectric material. A portion of the dielectric material around the crossing of the first and second conductors is removed to form a well that exposes respective outer surfaces of the first and second conductors and a molecule is deposited in the well such that the deposited molecule contacts the exposed outer surfaces of the first and second conductors.

Veena Misra

Papers

Electrical Characteristics of TaSi,N,, Gate Electrodes For Dual Gate Si-CMOS Devices

Electrical Characteristics of SiO 2 Deposited by Atomic Layer Deposition on 4H–SiC After Nitrous Oxide Anneal

Investigation of the Origin of $V_{T}/V_{\rm FB}$ Modulation by $\hbox{La}_{2}\hbox{O}_{3}$ Capping Layer Approaches for NMOS Application: Role of La Diffusion, Effect of Host High- $k$ Layer, and Interface Properties

Redox-active monolayers on nano-scale silicon electrodes.

Crossbar array microelectronic electrochemical cells and fabrication methods therefor