提高国产激光器组件直接调制速率与PIN－FET组件频响带宽的新技术

本文对如何提高国产１．５５μｍＩｎＧｒａＡｓｐＤＦＢ－ＬＤ组件直接高速调制速率以及国产ＰＩＮ－ＦＥＴ组件的频响带宽进行了理论与实验研究。在实验测量的基础上建立了国产ＬＤ组件小信号等效电路模型，对其调制响应速率的主要限制因素进行了分析，研制了高速ＤＦＢ－ＬＤ组件，将其调制速率提高到３．２ＧＨｚ。同时，在对谐振式ＰＩＮ－ＦＥＴ光接收机进行噪声分析的基础上，采用微波混合集成工艺研制了一个串联谐振式ＰＩＮ－ＦＥＴ光接收组件，有效地提高了ＰＩＮ－ＦＥＴ的频响带宽。     

LOWTRAN7在动态红外图像仿真系统中的应用及系统集成

介绍海洋作战环境下动态红外图像仿真系统的工程实现。着重介绍了ＬＯＷＴＲＡＮ模型在动态红外图像仿真系统中的应用及仿真系统中的数据流程、系统结构和系统集成中的主要情况。     

Correction to: Theoretical prediction of radiation-enhanced diffusion behavior in nickel under self-ion irradiation

Nuclear Science and Techniques - 166.6-MHz quarter-wave $$\beta =1$$ superconducting cavities have been adopted for the High Energy Photon Source, a 6-GeV diffraction-limited synchrotron light...     

表面n沟CCD的电离辐射损伤

本文报道了150光敏元表面n沟CCD(电荷耦合器件)在不同能量电子和γ射线辐照后的电离辐射效应。试验结果表明,转移失效率在≤10Gy时已明显增大。但大多数器件在累积剂量≤50Gy时,通过调整“胖零”注入仍可工作。在高剂量辐照期间,不同栅偏压器件的转移效率退化存在较大差异。应用高频和准静态C-V技术分析了参数退化的原因。     

P-阱、沟道区离子注入分布特性的测试分析与计算机模拟

CMOS集成电路在LSI、VLSI中占有显著地位,它是当今乃至今后一段时期集成电路发展的主流。研究CMOSIC沟道、P~-阱注入杂质的分布和再分布规律,对于指导工艺实践和提高电路性能具有现实意义。     

膨润土湿法离心提纯试验及工业应用研究

简述了膨润土湿法离心提纯的工作原理,介绍了实验室试验装置及对几种不同膨润土的实验室提纯试验结果,分析了离心机操作参数对提纯效果的影响,并对工业应用效果进行了分析研究.     

谈进口铁矿石中的有害元素

概述铁矿石中常见的有害伴生元素及其对冶炼、环境和人体健康的影响;介绍宁波口岸对进口铁矿石中12种有害元素含量的抽查情况,并对抽查结果进行分析;指出一些进口铁矿石存在不同程度的重金属污染的风险,应引起高度重视.     

球铁中微量元素Cu,Cr,Bi分布的SPM分析

球铁石墨相中含有多种微量元素,微量元素中的反球化元素的含量高低和分布对石墨球化、球铁的机械和力学性能有直接影响,为了深入研究球化机制,将球铁制成10μm厚的靶片,用SPM分析了微量元素Cr、Cu、Bi在球墨中和周围的分布,给出了球铁中微量元素二维等高线分布图。实验结果表明球铁中Cr、Cu主要分布在基体中,随着反球化元素Bi含量的增加,Cu逐渐侵入石墨相,在反球化作用中Cu和Bi可能是一组相关的元素。     

Wavelength Dependence of the Quantum Yield of Charge Separation in Photosynthesis: Photoacoustic Study of Light Energy Distribution among Various Pigment Complexes

The quantum yield spectra of photochemical charge separation have been measured in different photosynthetic materials [whole cells of wild type and mutant strains of green algae, photosystem I (PSI) and photosystem II (PSII) purified complexes, isolated photosynthetic membranes from plants (thylakoids), plant leaves] in the whole range of visible light, using a photoacoustic spectrometer previously described and slightly improved. The photochemical activity was sampled in dark-adapted material by a monochromatic laser flash of very low energy, i.e., under conditions where the concentration of open reaction centers was maximal. The efficiency of energy conversion by the different pigment-protein complexes is discussed on the basis of the quantum yield spectra. The respective contributions of PSI and PSII were measured in two distinct states (known as states 1 and 2) of energy distribution to the photosystems. In both states, light absorbed by the PSI antenna as a whole was found to be more efficient than that absorbed by the PSII antenna. Although in state 1 light energy is almost equally distributed amongst the two photosystems at 680 nm, about one-third of the light absorbed by PSII at this wavelength is not used for photochemistry under the conditions of our study. Under state 2 conditions in Chlamydomonas reinhardtii, the antenna size of PSI is considerably increased at the expense of PSII, and the quantum yield difference spectrum corresponding to the “mobile” antenna clearly identifies light-harvesting complex II (LHCII). The quantum yield spectra measured in the region of light absorption by carotenoids favor the view that the xanthophylls of the peripheral antenna (especially lutein in LHCII) have an efficient light-harvesting function, in contrast to β-carotene which acts probably as a protective energy trap in the core complexes.     

Mechanically Enhanced Reactivity of Silicon for the Formation of Silicon Nitride Composites

The chemical reactivity of silicon can be enhanced by mechanical activation. Ball milling elemental silicon powders with a small amount of carbon addition at ambient temperature has resulted in an enhanced nitridation of silicon at high temperatures. In comparison with powder mixtures without milling, the nitridation process at 1250°C has been accelerated by a factor of 9 and 23 by milling powder mixtures in N₂ and NH₃, respectively, before nitridation. The enhanced nitridation process for powders milled in N₂ is primarily attributed to the mechanical activation, whereas for powders milled in NH₃, the trapped nitrogen within the powder mixtures during milling also contributes to the enhanced nitridation process, in addition to the effect of the mechanical activation.