光存储技术中超分辨近场结构研究进展

超分辨近场结构(Super-RENS)是近场光学存储中最具有潜力和应用前景的方案之一。介绍了Super-RENS从基本类型到第三代Super-RENS的发展历程,简述了掩膜材料的研究进展以及Super-RENS在不同记录系统中的应用。展望了它的发展前景。     

Accelerator development in India

Accelerator development in India is reviewed with special emphasis on indigenous effort. It started with the 4 MeV cyclotron at the Saha Institute of Nuclear Physics, grew substantially with the installation of the Van de Graaff accelerators at Trombay and really came of age with the 224 cm Variable Energy Cyclotron at Calcutta, which resulted in considerable fall-out of technology. Simultaneously electron linac development has also taken place. Thus the stage is set for developing new types of accelerators such as the electron storage ring synchroton, and a proton/heavy ion synchrotron.     

Advances in ultrasonic production units for enhanced oil recovery in China

With the development of oil recovery technology, ultrasonic technology has been involved in oil production and oilfield development. The mechanism of ultrasonic wave plugging in near well is different from the conventional oil recovery technology. Ultrasonic oil production technique is an effective method to enhance oil production with low cost, good applicability, and no environmental pollution. The core part of ultrasonic oil production equipment for Enhanced Oil Recovery is a high-power ultrasonic transducer. The continuous high-power ultrasound is used to treat the reservoir, which changes the pore structure, the physical property and the state of the fluid, thus improving the permeability and flows conditions of the reservoir, and increasing the oil yield and oil recovery. Ultrasonic oil recovery equipment includes the generation of high-power ultrasonic signals, long-distance transmission and the conversion of electrical energy to acoustic energy. In this paper, state-of-the-art on the development of ultrasonic oil production devices for Enhanced Oil Recovery in China is introduced. The purpose of this paper is to provide a reference for the development of high-power ultrasonic oil extraction equipment and its promotion in tertiary oil recovery technology.     

Numerical studies on autoignition and detonation development from a hot spot in hydrogen/air mixtures

Detonation development inside spark ignition engines can result in the so called super-knock with extremely high pressure oscillation above 200?atm. In this study, numerical simulations of autoignitive reaction front propagation in hydrogen/air mixtures are conducted and the detonation development regime is investigated. A hot spot with linear temperature distribution is used to induce autoignitive reaction front propagation. With the change of temperature gradient or hot spot size, three typical autoignition reaction front modes are identified: supersonic reaction front; detonation development and subsonic reaction front. The effects of initial pressure, initial temperature, fuel type and equivalence ratio on detonation development regime are examined. It is found that the detonation development regime strongly depends on mixture composition (fuel and equivalence ratio) and thermal conditions (initial pressure and temperature). Therefore, to achieve the quantitative prediction of super-knock in engines, we need use the detonation development regime for specific fuel at specific initial temperature, initial pressure, and equivalence ratio.     

Ultrastructural analysis of spermiogenesis in the Eastern Fence Lizard,Sceloporus undulatus (Squamata: Phrynosomatidae)

Studies on reptilian sperm morphology have shown that variation exists at various taxonomic levels but studies on the ontogeny of variation are rare. Sperm development follows a generalized bauplan that includes acrosome development, nuclear condensation and elongation, and flagellar development. However, minute differences can be observed such as the presence/absence of manchette microtubules, structural organization during nuclear condensation, and presence/absence of a nuclear lacuna. The purpose of this investigation was to examine sperm development within the Sceloporus genus. The process begins with the development of an acrosomal complex from Golgi vesicles followed by nuclear condensation and elongation, which results in the presence of a nuclear lacuna. As the acrosomal complex differentiates, flagellar development commences with elongation of the distal centriole. Spermatid development culminates in a mature spermatid with a highly differentiated acrosomal complex, a condensed nucleus with a nuclear lacuna, and a differentiated flagellum. Although the overall developmental pattern is consistent with other squamate species, minute differences are observed, even within the same genus. For example there is variation in the presence/absence of an endoplasmic reticulum complex during acrosome development, presence/absence of a nuclear lacuna, and presence/absence of manchette microtubules within the three species of Sceloporus studied to date. Future studies concerning sperm morphology in closely related species will aid in our understanding of variation in sperm development and may prove to be useful in testing phylogenetic and evolutionary hypotheses.     

可调谐超构透镜的发展现状

随着新兴光学设备对微型化、一体化、智能化光学变焦系统的需求与日俱增,大大促进了纳米光电子学的迅猛发展。超构透镜是由具有特殊电磁属性的人造元素按照一定的排列方式组成的具有透镜功能的二维平面结构,其最大优点就是:轻薄和易于集成。然而,集成在超构透镜上的微纳结构一旦制备完成,便难以再改变其形貌或者尺寸,因而无法对其聚焦性能进行实时调控,限制了其功能及应用范围的进一步扩展。近年来,科学家们探索了实现超构透镜聚焦性能实时调控的多种途径,其中最引人注目的是将智能材料与超构透镜相结合。本文首先回顾了可调谐超构透镜的最新进展,分别详细阐述和分析了它们的调节原理和器件性能。最后,归纳分析了当前阻碍可调谐超构透镜发展的主要问题,并进一步对未来可调谐超构透镜的发展趋势做出了展望。     

Cherenkov Water Detectors in Particle Physics and Cosmic Rays

Among various types of Cherenkov detectors (solid, liquid and gaseous) created for different studies, the most impressive development was gained by water detectors: from the first detector with a volume of several liters in which the Cherenkov radiation was discovered, to the IceCube detector with a volume of one cubic kilometer. The review of the development of Cherenkov water detectors for various purposes and having different locations ? ground-based, underground and underwater–is presented in the paper. The prospects of their further development are also discussed.     

PIV measurement of toner particle motion in a micro-gap in the development process of electrophotography

In the development process of electrophotography, charged dielectric toner particles move in a micro-gap between the photoreceptor and the development roller to form images by the action of electrostatic force. To improve image quality, it is important to clarify the toner particle motion and the effects of the electric field on this motion. In the present study, Particle Image Velocimetry (PIV) was applied to measure the toner particle motion and the results were compared to calculated results. It was confirmed that the toner velocity increased with increasing electric field intensity, and that the measurement results agreed with the calculated results. These results indicated the usefulness of PIV in analyzing toner particle motion in the development process.     

Fragile X astrocytes induce developmental delays in dendrite maturation and synaptic protein expression

Background  

Fragile X syndrome is the most common inherited form of mental impairment characterized by cognitive impairment, attention deficit and autistic behaviours. The mouse model of Fragile X is used to study the underlying neurobiology associated with behavioral deficiencies. The effect of Fragile X glial cells on the development of neurons has not been studied. We used a co-culture technique in combination with morphometrics on immunostained neurons to investigate the role of astrocytes in the development delays associated with hippocampal neuron development.     

微流体技术在电子芯片冷却中的应用研究进展

随着微电子技术向小型化集成化及高频高速方向发展,计算机芯片集成度的提高受到因电子元器件发热而引起的热障所限制,芯片冷却问题成为影响计算机进一步发展的关键因素之一。介绍了电子芯片发展的现状及主要冷却方法的发展,从冷却驱动器件、微通道结构各个角度论述了微流体技术在电子芯片冷却中的重要作用,重点介绍了微槽道冷却和微喷冷却的微流体技术特征,论述了压电泵、电渗、热管等微流体驱动技术在冷却液驱动的应用。     

Ordering in alloys

Abstract

The continuous ordering process can be viewed as a development and a gradual amplification of concentration modulations with wave lengths of the order of a few lattice spacings. How the development of different concentration modulaltions leads to different superlattice structures in cubic systems is explained with the help of some illustrative examples. The importance of concentration modulations with special point wave vectors in the stability of the various coherent superlattice structures is discussed. Experimental evidences for such continuous ordering is cited from recent results on ordering in Ni-Mo alloys.

The evolution of ordering in some systems can also be viewed as progressively tiling the disordered lattice by superlattice tiles. When more than one type of coherent superlattice tiles compete, juxtaposition of different types of tiles can occur during the course of ordering. The transitional states between the short range and the long range ordered Ni-Mo alloys indeed exhibit such structures where different types of superlattice tiles decorate the fcc lattice. The role of special point concentration waves in the development of such structures will be discussed in relation to the secondary ordering processes involving two perpendicular ?1 ½ 0? waves and a combination of an ?1 ½ 0? and an appropriate ?100? wave.     

Longitudinal development of electromagnetic showers in directional spectrometer

The length of the longitudinal development of the electromagnetic shower induced by electrons with an energy of 26 GeV in a directional spectrometer consisting of a crystalline tungsten converter oriented along the ??111?? axis and a composite Cherenkov shower spectrometer is shorter in comparison with the length of the standard shower development by 20?C30% at a converter thickness from 2.7 to 8.4 mm.     

Generating terahertz radiation via optical rectification in nonlinear crystals: Theory and experimental results

Key principles of terahertz radiation generation via laser pulse optical rectification are reviewed. The development of theoretical concepts is considered in connection with recent experimental results. The usability of resonant effects and metamaterials for the further development of this technique of generation is analyzed.     

引张线技术在加速器准直测量中应用概述

为研究引张线技术在加速器准直测量中的应用和发展,首先简介了引张线技术原理,然后回顾了引张线准直法在加速器工程中的发展历史,接着介绍了引张线在加速器准直测量中的最新发展动态。最后讨论了各种引张线准直法的优缺点及其适宜环境,比较了国内外引张线准直法的发展与区别。指出引张线准直法的发展方向,给出了加速器准直测量的努力方向。     

太赫兹技术在农产品检测中的应用研究进展

我国是农业大国,保障粮食安全是国家发展的战略需要。农产品检测技术的应用和发展对监控质量,预防由农产品品质问题引发的安全事故至关重要。太赫兹(Terahertz, THz)波位于电磁频谱空隙,频率高于微波而低于红外线,具备光子能量低、穿透性好、能表征分子结构等优点。基于太赫兹波的光谱检测技术受到研究人员广泛关注,在生物医学、安全检查等方面得到应用,被证明是一种可靠的检测手段。在农产品应用领域,太赫兹波特有的非接触、无标记检测能力为农产品成分分析、质量控制提供了技术手段,其良好的穿透性和无损害性,可以用来在不破坏农产品表面及外包装的前提下,检测内部成分变化。与其他光谱(超声、 X射线、红外等)检测手段相比,太赫兹波频率范围宽、表征能力强,可实现对目标物质的快速无损检测。近几年,随着太赫兹发射源、探测器等设备以及光谱和成像技术的发展,其在农产品领域的应用有了新的进展。通过收集整理近期的文献资料,综述了太赫兹技术在农产品检测方面的应用拓展和研究成果,总结了目前存在的应用局限。在此基础上,对未来太赫兹光谱和图像检测的研究方向进行了展望,提出提高检测灵敏度和检测速度是农产品领域太赫兹技术产业化应用...     

直线感应加速器模拟软件多功能发射模块开发

在模拟直线感应加速器电子束输运过程中,为了正确设置注入器电子束参数,以注发射模型为基础,研发了可设置发射度、能散和电子束倾斜的多功能发射模型。理论研究了发射度、能散以及电子束倾斜角度,并将这些理论实现到发射模块上。建模对多功能发射模块进行测试,比较设定的电子束参数与模拟测定的电子束参数。通过比较,观测到设定电子束参数与模拟测定值一致,验证了多功能模块开发的正确性。     

激光光钳在生物技术中的应用新进展

介绍了激光光钳在生物技术中的应用，阐述了应用机理并展望了进一步的发展。     

Contemporary measures for noise reduction in airport surroundings

Air traffic, with its adverse influence on environment, is beginning to jeopardize its own development. Air traffic noise in vicinity of airports is seen as one of the important constraints of air traffic development. Committee on Aviation Environmental Protection of International Civil Aviation Organization (ICAO) recommends procedures for noise decreasing in vicinity of airports, mentioning that measures for noise reduction should not aim at unique solution, but at combination of different solutions. In this paper, ICAO standards and recommended practices, designed for “Balanced approach” to aircraft noise management around airports, are presented. An overview of measures applied by airports worldwide in order to reduce noise in the surroundings is provided showing their frequency and variety. Additionally, directions on development of new measures for the same purpose, originated as a response to ICAO recommendations, are presented.     

Physics of atomic collisions in retrospect

The classic work by Mott and Massey, in which the scope of the physics of atomic collisions was defined, was published about 65 years ago. Since then, this field has undergone considerable development. In fact, all the theoretical methods named by Mott and Massey have been implemented to some extent. As for experiment, the measurements performed, which are differential with respect to several parameters, have provided for reliable testing of the mechanisms proposed. The physics of atomic collisions has been developed to the point that we can look back on the road taken and discover many achievements which have promoted its development. Progress in science is usually associated with highly concentrated efforts on the part of a critical number of investigators to solve a specific problem, which is widely regarded as being of great importance. Such a “breakthrough” is usually followed by rapid development of the field. In this respect, the physics of atomic collisions is no exception. It has known periods of highly concentrated efforts aimed at solving specific problems and breakthroughs followed by rapid development and subsequent periods of stagnation. The cycles have repeated: a new area for concentrated efforts is discovered, a breakthrough occurs, and a new concept is established. Some of these cycles are analyzed from the standpoint of their significance to atomic physics as a whole. Zh. Tekh. Fiz. 69, 22–26 (September 1999)     

New frontiers in computing and data analysis – the European perspectives

ABSTRACT

Nowadays, Europe is heavily engaged in the evolution of a new generation of high-performance computing (HPC), and new perspectives are looking at the emerging computational era called exascale. The presence of converging, domain-independent interests on Big Data among different communities, from Information Communication Technologies (ITC) to Life Sciences, Physics, Astrophysics, Space Sciences and many other fields, as well as the development of new skills, is leading to the establishment of specific collaborations with the aim of exploiting knowledge, capacities and research and innovation potential from different communities. The new program of Europe (named EuroHPC) is encouraging the sharing of these experiences and the cooperation between different entities like scientific research centers, small and medium-sized enterprises (SMEs) and private industries, for joint actions and the development of new skills in the Big Data and artificial intelligence (AI) domains. This program has two main pillars: ‘Supercomputing and Data Infrastructure Programme’ to deliver two world-class precursors of exascale supercomputers on 2020 and ‘Research and Innovation Programme’ on HPC to support the development of European supercomputing technology with the co-design of European exascale machines and to foster applications, skills development and a wider use of the new generation of computing systems. The co-design of these new systems, considering the big amount of data they need to handle with increasingly complexity, will also drive the development of a new generation of artificial intelligence techniques and visual analytics systems to underpin more accurate investigations. This paper is an analysis of the evolution of computing from a European perspective, looking at new generation systems and data analysis techniques in the era of Big Data, illustrating ideas with examples developed within the context of a specific physics field.