Transfer of powerful laser radiation in optical media: Appearance of “optical turbulence”

The passage of powerful laser radiation in a flat layer of diathermal medium with specularly reflecting and diffusely emitting boundaries is studied. The conditions under which optical turbulence arises are examined. It is shown that the optical characteristics of the boundaries of the flat layer are bifurcational parameters.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 61, No. 1, pp. 21–25, July, 1991.     

128层螺旋CT

<正>日前,辽宁东软医疗系统有限公司正式推出Neu Viz128精睿CT,并出口到南亚、北非等国际市场。这是我国第一台拥有完全自主知识产权和核心技术的128层螺旋CT,其成功问世并进军国际高端CT市场,标志着高端医疗器械市场由国外厂商垄断的局面被打破。1998年,国产CT在辽宁东软医疗的努力下首次实现产业化,这使得中国继美、日、德、荷之后成为世界第五大CT整机生产国和出口国。Neu Viz128     

Electrical and optical properties of µc-SiH films

Microcrystalline silicon films have been found quite useful in amorphous silicon solar cells as a contact material in n-i-p cells. Microcrystalline silicon films are obtained when amorphous silicon films are prepared by R.F. glow discharge of SiH₄ + H₂ at higher power ratings. These films possess higher conductivity as well as high transmission than amorphous silicon films. The present paper reports the preparation technique ofμc-SiH films using R.F. capacitive glow discharge of hydrogen-diluted silane. X-ray studies andtem studies of the films indicate microcrystallinity of the films. The electrical and optical properties are also reported.     

Reflection optical encoders as three-grating moiré systems

Reflection optical encoders are studied as three-grating moiré systems. An analysis is made of the differences that may appear between it and the standard case in which an optical encoder is regarded as a two-grating system.     

雷克沙推出128GB SDXC存储卡

2011年1月4日．雷克沙在CES大展上推出128GB SDXC存储卡．推荐价格为700美元（约4613元人民币），据悉．128GB主要面向专业用户．拥有133X的读取速度．还可实现20MB/s的写入。     

Investigation on certain optical,thermal, and Z-scan studies of nonlinear optical tris–sarcosine calcium chloride single crystal

Slow solvent evaporation was used to produce single crystals of Tris–Sarcosine Calcium Chloride (TSCC) from aqueous solution. The cell parameters of the grown crystals were determined using the single-crystal X-ray diffraction analysis. The existence of functional groups in TSCC was confirmed using the Fourier Transform Infrared spectrum analysis. Energy-Dispersive X-ray Analysis verified the chemical composition of the TSCC crystal. The optical transmittance of TSCC was greater than 90%, according to the UV–Vis–NIR transmittance spectrum measurements. This indicates TSCC is an appropriate material for NLO applications. The optical characteristics of the grown crystal, including band gap energy, were determined. The photoluminescence characteristics of TSCC crystal were also studied in order to better understand its optical device manufacturing. The thermal behavior of TSCC was investigated using the TGA/DTA and DSC studies. For various temperatures, the fluctuation of the dielectric constant and dielectric loss with regard to frequency variation was examined and the results were described in depth. The TSCC susceptibility χ⁽³⁾ and nonlinear refractive index n₂ values were evaluated. The saturation absorption of TSCC was revealed by open aperture Z-scan technique, and the self-defocusing performance was revealed by closed aperture Z-scan measurements.

     

MoS₂ nanosheet phototransistors with thickness-modulated optical energy gap

We report on the fabrication of top-gate phototransistors based on a few-layered MoS(2) nanosheet with a transparent gate electrode. Our devices with triple MoS(2) layers exhibited excellent photodetection capabilities for red light, while those with single- and double-layers turned out to be quite useful for green light detection. The varied functionalities are attributed to energy gap modulation by the number of MoS(2) layers. The photoelectric probing on working transistors with the nanosheets demonstrates that single-layer MoS(2) has a significant energy bandgap of 1.8 eV, while those of double- and triple-layer MoS(2) reduce to 1.65 and 1.35 eV, respectively.     

紫外多阳极(128×128)微通道阵列光电倍增管的研制

详细报道了新研制的紫外多阳极微通道阵列光电倍增管。该器件采用了叠合式阵列阳极(128×128)、端窗式“日盲”紫外光电阴极(碲铷RbTe)、高增益的Z型微通道板组件、近贴聚焦结构等先进技术。器件的主要性能参数为阴极发射灵敏度18 mA/W,增益2×10     

Network-bridge structure of CdSxSe₁-x nanowire-based optical sensors

We report on the synthesis of CdS(x)Se(1-x) nanowires by pulsed-laser deposition and their application to optical sensors. We developed a suspended structure for a nanowire-based optical sensor. This structure comprised separated nanowires that were suspended in the desired position between two pre-patterned electrodes. We found from measuring photoluminescence that the direct bandgap energy of the nanowires changes linearly with the composition of sulfur in the nanowires. These findings show that the bandgap energy of the nanowires can be systematically modulated in the range of 1.7-2.4 eV. The cutoff wavelength of the fabricated optical sensors shifted toward the longer wavelength with increasing sulfur composition. We found that the CdS(x)Se(1-x) nanowires have sufficient potential for a broad band optoelectronic device involving photosensors.     

Rare-earth chalcogenides — an emerging class of optical materials

Sulphide compounds belong to the family of chalcogenides and are well known for their optical and electronic properties. They possess good optical properties because of their ability to transmit into the infrared (IR) region. Several sulphide glasses are known to exist which exhibit far infrared transmission and are also useful semiconductors. In recent years, there has been an increasing interest in IR materials to be used on surveillance equipment. This led to the identification of several new crystalline sulphide materials which can transmit very far into the IR region (up to a wavelength of 14 m). Crystalline and amorphous rare-earth sulphides emerged as a new class of materials, which possess several unique optical and electronic properties. This paper reviews the status of these rare-earth sulphide amorphous and polycrystalline materials, the techniques used to process these materials and discusses their structure, thermal, mechanical and optical properties. Conventional and emergent novel chemical processing techniques that are used for synthesizing these materials are reviewed in detail. The use of metallorganic precursors and the modification of their chemistry to tailor the composition of the final ceramic are illustrated. The potential of these chemical techniques and their advantages over the conventional solid state techniques used for processing sulphide ceramics is discussed, particularly in light of their successful applications in processing novel electronic and optical oxide ceramics.     

基于ATMEGA128的汉字显示屏设计

在现代工业控制和一些智能化仪器仪表中,越来越多的场所需要用点阵图形显示器显示汉字,用以显示仪器当前的运行状况。汉字显示方式是先根据所需要的汉字提取汉字点阵（如16×16点阵）,将点阵文件存方ROM,形成新的汉字编码,而在使用时刚需要先根据新的汉字编码组成语句,再由MCU根据新编码提取相应的点阵进行汉字显示。本设计是以单片机的基本语言C语言来进行软件设计,以ICCAVR进行软件编译,硬件连接是用Atmega128单片机的I／O端口与AMPIRE128×64液晶屏相连,从而达到在液晶屏上显示汉字的目的。     

通用128用户PCI-Qbus桥接器的实现

设计了一种适合于多用户接入设备的通用128用户PCI-Qbus(Queue bus)桥接器。采用队列和链表结构进行数据收发管理,收发方向上的用户状态信息和桥接器状态信息可以独立传递,能够独立配置每个用户的工作属性。采用Xilinx的FPGA xc2s200pq208和xcv600ehq240分别实现PCI-Qbus桥接器和作为用户电路的128通道HDLC数据帧处理器,建立了桥接器功能测试系统。测试表明可以满足128个64Kbit／s用户的数据传输的要求。     

我国已发现128种新矿物

正在第二届中国(长沙)国际矿物宝石博览会高峰论坛上,地质矿物学家谢先德透露,截至2012年底,国际矿物学协会新矿物委员会批准的独立新矿物共计4751种,其中我国发现的有124种。加上2013年发现的4种,我国目前已发现新矿物128种。谢先德介绍,我国幅员广阔,在特殊矿山和陨石中发现新矿物的几率较大,如白云鄂博1958年以来共发现15种新矿物;从湖北随州陨石中发现的涂氏磷钙石,为自然界发现的第一个磷酸盐高压相矿物,是一种潜在的     

Analysis of optical near-field images by Karhunen-Loève transformation

With regard to classical image transformations, the Karhunen-Loève transform is based on the statistical analysis of signal or image data. We propose using it to analyze and recognize the content of images generated in near-field microscopy. It is shown that such a transform is an efficient tool for separating actual information from noise without reducing the spatial-frequency band.     

Investigation of optical properties of core–shell silicon nanowires

The ability to control the size, orientation, composition and morphology of silicon nanowires (SiNWs) presents an ideal platform for exploring a wide range of potential technological applications. In this work, we demonstrated the detail study of optical properties of highly disordered core–shell SiNWs that were grown by atmospheric pressure chemical vapor deposition. The microstructure of SiNWs was characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The TEM study shows that the SiNWs consists of crystalline core silicon surrounded by thick amorphous silicon oxide. The total diameter including the outer SiO₂ sheath was 60–80 nm. The reflection and absorption of a-SiO₂/c-SiNWs were affected by process parameter like silane flow rate and hydrogen dilution. The optical reflection of SiNWs decreased with increasing photon energy across the visible and near the ultraviolet range, approaching moth's eye antireflection. Specifically, a minimum reflection of 2–3% was observed at 400 nm. The band gap is estimated at ∼1.32 eV by quasi-direct band Tauc's plot. The sum of localized states at the band edge is ∼0.53 eV. Straight SiNWs have lower reflection than those of nanoparticles mixed SiNWs and coil mixed SiNWs. The reflection and absorption of SiO₂/SiNWs were confirmed to respond strongly to infrared with increasing H₂ flow rate.     

Preparation and optical properties of TPPS-doped metal–carboxylate-salts glasses

Li and Na carboxylate salts glasses with different number chains containing molecules of Tetraphenyl-porphine-tetrasulfonic acid (TPPS) were prepared by the melting method. TPPS doped in the glasses had the same form as the TPPS in the aqueous solutions. However the form of TPPS in the glasses changed because TPPS reacted with matrix glass during the melting process. Tetraphenyl-porphine (TPP) could no be incorporated into the Li and Na carboxylate salts glasses by the present melting method. The free base TPPS is important for photochemical hole burning (PHB) properties, and a mixed metal–carboxylate salts glasses containing free-base TPPS, which is the active form for PHB, were prepared by controlling the melting condition. It was found that a preparation condition such as holding time of the melts affects the formation of the complex of the TPPS and that in the mixed metal–carboxylate salts melts the TPPS formed a complex with Li but did not form a complex with Na.     

Self-consistent optical constants of sputter-deposited B₄C thin films

The optical constants of ion-beam-sputtered B?C films have been measured by ellipsometry in the 190-950 nm range. The set of data has been extended toward both shorter and longer wavelengths with data in the literature, along with interpolations and extrapolations, in order to obtain a self-consistent set of data by means of Kramers-Kr?nig analysis. All data correspond to films that were deposited by sputtering on nonheated substrates, and hence they are expected to be amorphous. The B?C bandgap was calculated as a fitting parameter of Tauc equations for indirect transitions using the present optical constants. Good global accuracy of the data was estimated through the use of various sum rules. The consistent data set includes the visible to the extreme UV (EUV); this large spectrum of characterization will enable the design of multilayer coatings that combine a relatively high reflectance in parts of the EUV with a desired performance at a secondary range, such as the visible.