美国银盐照相市场呈上升趋势

近年来,随着银盐照相技术和数字成像技术的快速结合,图像记录和打印／扩印数字化的发展趋势使银盐照相产品在信息存储、档案管理、新闻广告、印刷出版、电子数据、摄影艺术、网络影像和休闲娱乐等领域找到了广阔的应用范围,从而大大地巩固了银盐照相产品的市场地位。广大业余摄影爱好者拍摄、获取、处理、传送、应用、共享和储存图片的途径和解决方案越来越多。人们一直担忧的传统银盐照相产品的市场销售量不但没有减少,反而在逐年增加。据照相专业杂志报道,２０００年全世界售出的传统照相机接近７０００万台,胶卷的消费量已经超过３…     

美国传统消费者照相市场

在刚刚过去的 2 0 0 0年 ,传统银盐照相产品和数字成像产品在世界照相市场上发生了翻天覆地的变化。随着银盐成像技术和数字成像技术的快速结合 ,图像信息数字化的发展趋势使银盐照相产品在信息存储、档案管理、新闻广告、印刷出版、电子数据、摄影艺术、网络影像和休闲娱乐等领域扩大了实际应用范围 ,从而大大地巩固了银盐照相产品的市场地位。各国业余摄影爱好者拍摄、获取、处理、传送、应用、共享和储存图片的途径和解决方案越来越多。人们一直担忧的传统银盐照相产品的市场销售量不但没有减少 ,反而在逐年增加。据报道 ,2 0 0 0年全世…     

新世纪的影像工业和照相市场

当人类文明社会进入崭新的２１世纪时,世界影像工业和影像市场也进入了一个前所未有的快速发展时期。一方面电子图像技术的迅猛发展使数字影像技术和数字成像产品日益成熟和普及,“照相不用胶卷”已经成为现实;另一方面具有１６０年历史的传统银盐照相技术和产品也在不断创新、改进、完善,并积极与数字成像技术快速结合起来。随着全球经济一体化,数字技术和信息网络飞速发展,世界照相行业将在图像拍摄、获取、处理、传送、应用、共享和存储等方面发挥越来越大的作用。各类照相／成像技术和产品也会更广泛地应用于航天遥感、科技开发、…     

影像工业与影像市场的新发展

在 2 1世纪的开局之年 ,传统银盐和数字成像技术继续得到迅猛发展 ,世界影像工业和影像市场发生了巨大的变化。 2 0 0 1年传统银盐照相市场的消费量开始从 2 0 0 0年的顶峰回落 ,而数字成像市场的销售量则保持着 5 0 %以上的增长速度。由于传统银盐成像技术、数字成像技术和ＩＴ业技术的集合 ,信息影像工业在世界范围内逐渐形成。1　传统银盐照相市场2 0世纪 90年代后期 ,随着银盐照相技术和数字成像技术的快速结合 ,图像信息数字化的发展趋势巩固了银盐照相产品的市场地位。各国业余摄影爱好者拍摄、获取、处理、传送、应用、共享和储存图…     

数字照相技术在刑事照相中的应用

随着高科技的迅猛发展,特别是数据化已是当今信息革命的灵魂,当今摄影领域正在掀起一场革命。近年来,世界各大摄影器材和感光材料厂商都投入巨资研制开发新一代数字摄影器材,并已经在新闻、体育、广告摄影等领域得到了广泛运用。本文就数字照相技术在刑事照相领域中的应用,谈几点粗浅的认识。１　数字照相技术的特点和技术性能数字照相机的最大特点是无需传统的银盐感光材料即可直接拍摄,直接储存,直接处理,直接印制,直接传送。它采用了与传统相机完全不同的技术方式。传统相机是理化方法的结合物,其前期是借助于物理方法将影像记…     

新世纪四大照相公司的经营状况

概述 ２１世纪是经济全球化,科学技术信息化和数字化的时代。世界影像材料工业与其它高科技工业一样充满了激烈的变化和挑战。一方面,数字成像技术和产品发展迅速,传统银盐照相产品和数字成像产品互相渗透、互相结合的步伐加快,影像材料的应用范围不断扩大;另一方面,西方发达国家的经济从２０００年下半年进入低迷状态,照相市场发展势头和影像网络化趋势受挫,网络图像传送和照片消费量增幅明显放慢。据国外期刊报道,美国经济将继续疲软,西欧经济增速趋缓,而日本经济２００１年第一季度则出现负增长。受发达国家经济形势恶化的影…     

刑事特种照相的应用与发展趋势

本文摘要介绍了应用於刑事特种照相的一些新技术，简明阐述了其原理及特征，如：红外照相、紫外照相．紫外荧光照相，红外荧光照相、偏振光显微镜照相、全息照相等．     

国外文摘

1986年照相的进展本文对世界上照相科学与技术的进展进行了综述。并报告了1986年世界上多种照相杂志上的各种消息与专题。条目分为工业生产、卤化银照相材料,彩色照相、非银体系、照相理论、照相过程、应用,摄影机械、一步摄影、电子照相和设备。     

数字照相市场的形成与发展

通过对数字摄影的形成和发展,简要介绍了数字照相产品在美国和中国的发展情况,指出１９９８年底和１９９９年初是世界照相市场数字时代的开始。随着数字照相的应用范围不断扩大,数字成像产品的市场份额不断增加,数字照相将与传统照相优势互补、互相促进、共同发展。预计在２１世纪,数字照相将成为日常生活中必不可少的一种照相娱乐方式。     

照相感光材料工业进展

数字影像技术和产品的快速发展使照相感光材料工业发生很大变化,传统银盐照相产品的需求快速萎缩,数字影像技术逐步取代传统照相技术,影像材料行业的应用领域不断翻新和扩展。本文叙述了近年来国内照相感光材料工业的进展,照相材料新产品和市场变化。     

25th Anniversary Article: Charge Transport and Recombination in Polymer Light‐Emitting Diodes

This article reviews the basic physical processes of charge transport and recombination in organic semiconductors. As a workhorse, LEDs based on a single layer of poly(p‐phenylene vinylene) (PPV) derivatives are used. The hole transport in these PPV derivatives is governed by trap‐free space‐charge‐limited conduction, with the mobility depending on the electric field and charge‐carrier density. These dependencies are generally described in the framework of hopping transport in a Gaussian density of states distribution. The electron transport on the other hand is orders of magnitude lower than the hole transport. The reason is that electron transport is hindered by the presence of a universal electron trap, located at 3.6 eV below vacuum with a typical density of ca. 3 × 10¹⁷ cm^?3. The trapped electrons recombine with free holes via a non‐radiative trap‐assisted recombination process, which is a competing loss process with respect to the emissive bimolecular Langevin recombination. The trap‐assisted recombination in disordered organic semiconductors is governed by the diffusion of the free carrier (hole) towards the trapped carrier (electron), similar to the Langevin recombination of free carriers where both carriers are mobile. As a result, with the charge‐carrier mobilities and amount of trapping centers known from charge‐transport measurements, the radiative recombination as well as loss processes in disordered organic semiconductors can be fully predicted. Evidently, future work should focus on the identification and removing of electron traps. This will not only eliminate the non‐radiative trap‐assisted recombination, but, in addition, will shift the recombination zone towards the center of the device, leading to an efficiency improvement of more than a factor of two in single‐layer polymer LEDs.     

复合型导电高分子材料导电机理研究及电阻率计算

综述了复合型导电高分子材料的导电机理，描述了电子的微观传输过程；总结了计算电阻率的两种常用方法──渗流理论和量子力学隧道效应，分析了计算电阻率的各种模型和计算方法。     

Linear Electron Chains on the Liquid Helium Surface: Carrier Transport

The unique system - linear electron chains on the liquid helium surface was realized experimentally for the first time. The system was realized using curvature of the liquid helium surface film covering a profiled substrate with a small dielectric constant and a pressing electric field holding electrons in the liquid channels. The conductivity of carriers in linear electron chains and magnetoresistance of a quasi-one-dimensional system have been measured in the temperature range 0.5 - 1.8 K in holding electric fields up to 1 kV/cm. The transport properties of the system depend on the substrate cleanness. For a clean system the electron mobility increases with decreasing temperature, the data are in good agreement with the existing theory which describes transport properties in a one-dimensional electron system without localization. Charging of substrate leads to the localization process in electron chains. It has been shown that in the absence of localization magnetoresistance of a quasi-one-dimensional system on liquid helium in the region of ripplon scattering increases with increasing magnetic field.     

Flux dependent MeV self-ion-induced effects on Au nanostructures: dramatic mass transport and nanosilicide formation

We report a direct observation of dramatic mass transport due to 1.5?MeV Au(2+) ion impact on isolated Au nanostructures of average size ≈7.6?nm and height ≈6.9?nm that are deposited on Si(111) substrate under high flux (3.2 × 10(10)-6.3 × 10(12)?ions?cm(-2)?s(-1)) conditions. The mass transport from nanostructures was found to extend up to a distance of about 60?nm into the substrate, much beyond their size. This forward mass transport is compared with the recoil implantation profiles using SRIM simulation. The observed anomalies with theory and simulations are discussed. At a given energy, the incident flux plays a major role in mass transport and its redistribution. The mass transport is explained on the basis of thermal effects and the creation of rapid diffusion paths in the nanoscale regime during the course of ion irradiation. The unusual mass transport is found to be associated with the formation of gold silicide nano-alloys at subsurfaces. The complexity of the ion-nanostructure interaction process is discussed with a direct observation of melting (in the form of spherical fragments on the surface) phenomena. Transmission electron microscopy, scanning transmission electron microscopy, and Rutherford backscattering spectroscopy methods have been used.     

钙钛矿太阳能电池的研究进展

作为一种新型清洁可再生能源,钙钛矿太阳能电池(Perovskite solar cells,PSC)从发展至今已取得了重大的突破,成为研究的热点。主要介绍了钙钛矿太阳能电池的基本结构和工作原理及电子传输层、钙钛矿层、空穴传输层的制备方法,以及在发展过程中所面临的技术问题,最后展望了钙钛矿太阳能电池未来的研究重点及发展前景。     

Direct imaging of single Au atoms within GaAs nanowires

Incorporation of catalyst atoms during the growth process of semiconductor nanowires reduces the electron mean free path and degrades their electronic properties. Aberration-corrected scanning transmission electron microscopy (STEM) is now capable of directly imaging single Au atoms within the dense matrix of a GaAs crystal, by slightly tilting the GaAs lattice planes with respect to the incident electron beam. Au doping values in the order of 10(17-18) cm(3) were measured, making ballistic transport through the nanowires practically inaccessible.     

Crystal face-dependent nanopiezotronics of an obliquely aligned InN nanorod array

This paper proposes an obliquely aligned InN nanorod array to maximize nanorod deformation in the application of nanopiezotronics. The surface-dependent piezotronic I-V characteristics of the InN nanorod array with exposed polar (0002) and semipolar ( ?1102) planes were studied by conductive atomic force microscopy. The effects of the piezopotential, created in the InN under straining, and the surface quantum states on the transport behavior of charge carriers in different crystal planes of the InN nanorod were investigated. The crystal plane-dependent electron density in the electron surface accumulation layer and the strain-dependent piezopotential distribution modulate the interfacial contact of the Schottky characteristics for the (0002) plane and the quasi-ohmic behavior for the ( ?1102) plane. Regarding the piezotronic properties under applied forces, the Schottky barrier height increases in conjunction with the deflection force with high current density at large biases because of tunneling. The strain-induced piezopotential can thus tune the transport process of the charge carriers inside the InN nanorod over a larger range than in ZnO. The quantized surface electron accumulation layer is demonstrated to modulate the piezopotential-dependent carrier transport at the metal/InN interfaces and become an important factor in the design of InN-based piezotronic devices and nanogenerators.     

Growth of one-dimensional Si/SiGe heterostructures by thermal CVD

The first results on a simple new process for the direct fabrication of one-dimensional superlattices using common CVD chambers are presented. The experiments were carried out in a 200?mm industrial Centura reactor (Applied Materials). Low dimensionality and superlattices allow a significant increase in the figure of merit of thermoelectrics by controlling the transport of phonons and electrons. The monocrystalline nanowires produced according to this process are both one-dimensional and present heterostructures, with very thin layers (40?nm) of Si and SiGe. Concentrations up to 30?at.% Ge were obtained in the SiGe parts. Complementary techniques including transmission electronic microscopy (TEM), selected area electron diffraction (SAED), energy dispersive x-ray spectroscopy (EDS), scanning transmission electron microscopy (STEM) in bright field and high angle annular dark field (HAADF STEM), and energy-filtered transmission electron microscopy (EF-TEM) were used to characterize the nanoheterostructures.     

The effects of crystallography on grain-boundary migration in alumina

The sintering process of ceramics involves mass transport across grain boundaries resulting in the migration of these boundaries. When there is a liquid at the interface—as in liquid-phase sintering—the mass transport can be enhanced. In this study, electron backscatter diffraction has been used to examine grain-boundary migration of controlled interfaces in alumina. The interfaces were prepared by hot pressing single-crystal and polycrystalline alumina to single-crystal alumina substrates of known orientation. EBSD patterns, taken near the sintered interfaces, have been used to study the effects of crystallography on migration direction and rate.     

Shrinking a carbon nanotube

We report a method to controllably alter the diameter of an individual carbon nanotube. The combination of defect formation via electron irradiation and simultaneous resistive heating and electromigration in vacuum causes the nanotube to continuously transform into a high-quality nanotube of successively smaller diameter, as observed by transmission electron microscopy. The process can be halted at any diameter. Electronic transport measurements performed in situ reveal a striking dependence of conductance on nanotube geometry. As the diameter of the nanotube is reduced to near zero into the carbon chain regime, we observe negative differential resistance.