Modulation of transmission in different electronic junctions by aminopyridine

Summary 4 distinct electronic inputs can be identified in amphibian motoneurons perfused with calcium-free solution containing manganese. The differential effect of 4-aminopyridine on different electrotonic junctions may reflect the peculiarities of molecular architecture of potassium channels in different electrically excitable presynaptic membranes.We thank Prof. D. R. Curtis, of National University Canberra, for the gift of 4-aminopyridine.     

Functional and pharmacological induced structural changes of the cystic fibrosis transmembrane conductance regulator in the membrane solved using SAXS

The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is a membrane-integral protein that belongs to the ATP-binding cassette superfamily. Mutations in the CFTR gene cause cystic fibrosis in which salt, water, and protein transports are defective in various tissues. To investigate the conformation of the CFTR in the membrane, we applied the small-angle x-ray scattering (SAXS) technique on microsomal membranes extracted from NIH/3T3 cells permanentely transfected with wild-type (WT) CFTR and with CFTR carrying the ΔF508 mutation. The electronic density profile of the membranes was calculated from the SAXS data, assuming the lipid bilayer electronic density to be composed by a series of Gaussian shells. The data indicate that membranes in the microsome vesicles, that contain mostly endoplasmic reticulum membranes, are oriented in the outside-out conformation. Phosphorylation does not change significantly the electronic density profile, while dephosphorylation produces a significant modification in the inner side of the profile. Thus, we conclude that the CFTR and its associated protein complex in microsomes are mostly phosphorylated. The electronic density profile of the ΔF508-CFTR microsomes is completely different from WT, suggesting a different assemblage of the proteins in the membranes. Low-temperature treatment of cells rescues the ΔF508-CFTR protein, resulting in a conformation that resembles the WT. Differently, treatment with the corrector VX-809 modifies the electronic profile of ΔF508-CFTR membrane, but does not recover completely the WT conformation. To our knowledge, this is the first report of a direct physical measurement of the structure of membranes containing CFTR in its native environment and in different functional and pharmacological conditions.     

Tubes,randomness, and Brownian motions: or,how engineers learned to start worrying about electronic noise

In this paper, we examine the pioneering research on electronic noise—the current fluctuations in electronic circuit devices due to their intrinsic physical characteristics rather than their defects—in Germany and the U.S. during the 1910s–1920s. Such research was not just another demonstration of the general randomness of the physical world Einstein’s work on Brownian motion had revealed. In contrast, we stress the importance of a particular engineering context to electronic noise studies: the motivation to design and improve high-gain thermionic-tube amplifiers for radio and wired communications. Engineering scientists’ endeavors to understand electronic noise started in 1918, when Walter Schottky at Siemens formulated a theory of “shot noise,” current fluctuations owing to the random emissions of discrete electrons in a tube. Schottky’s theory was revised and experimentally tested at Siemens, General Electric, and AT&T during the 1920s, leading to the discoveries of several other types of noise and an increasing interest in the thermal fluctuations in electronic circuits. In 1925–1928, J.B. Johnson and Harry Nyquist at Bell Labs developed a theory of thermal noise for any electrical resistor at a non-zero temperature. Although these studies were initiated to chart the fundamental performance limit of electronic technology, they ended up assisting the empirical determination of individual electronic components’ characteristics.     

Net-shape forming of composite packages with high thermal conductivity

The continuing miniaturization of electronic devices in microelectronics and semiconductors drives the development of new packaging materials with enhanced thermal conductivity to dissipate the heat generated in electronic packages.In recent years,several promising composite materials with high thermal conductivity have been developed successfully for high performance electronic equipment to replace the traditional Kovar and Cu/W or Cu/Mo alloys,such as SiCp/Al,SICp/Cu,diamond/Al and diamond/Cu.However,thes...     

Inhibition par les sels de tetrazolium de l'activité monoamine-oxydasique d'une suspension mitochondriale de cerveau de mouton

Summary 5 tetrazolium salts used in electronic microscopy are non-competitive inhibitors of monoaminoxidasic activity of a sheep's brain mitochondrial suspension. This inhibition indicates that special caution must be taken in using these salts for detection of monoamine oxidase in optic or electronic microscopy.     

有机功能材料薄膜与器件

具有光、电、磁物理功能的有机材料的出现促进新思想、新概念、新材料的发展；有机功能材料的电子状态、导电机理以及杂质的影响完全有别于无机金属和半导体，因此，在深入探索结构与功能的关系的基础上，有可能开展分子、聚集态以及器件设计的研究。若与有机化合物的结构多样化，良好的加工性、成膜和成纤性等特点相结合，有可能实现无机电子材料所难兼具的电子行为。进而实现“分子电路”的设想。这里，我们对有机功能材料的基本概念、种类，功能材料薄膜的沉积、器件的构筑，分子电子学和分子器件的概念作了一个较为全面的介绍。     

陶瓷颗粒(纤维)增强聚合物复合电子封装与基板材料

本文论述了陶瓷颗粒(纤维)增强聚合物基复合电子封装与基板材料体系和性能特点,介绍了复合基板材料的实验研究和理论研究进展情况,根据实验研究和文献报道并结合目前在微电子封装领域广泛应用的环氧塑封材料,对复合电子封装与基板材料的发展趋势进行了分析和评述。     

Sn及Sn合金的微观断裂行为

微电子系统中互连尺寸的微细化使构成焊点的钎料合金的力学性能成为影响电子封装与组装产品可靠性的关键因素。因此,在微米及纳米尺度深刻掌握Sn基钎料合金的断裂行为对于更好地预测焊点可靠性具有重要意义。本文针对100Sn、63Sn37Pb、96.5Sn3.5Ag三种Sn及Sn合金,在进行力学性能测试和显微组织分析的基础上,考察了Sn及Sn合金在微米尺度上的动态断裂机制,以及纳米尺度上裂纹尖端的真实物理过程,阐述了Sn基体、含铅Sn合金和无铅Sn合金三者互有关联又各有不同的微观断裂行为特征。     

汽车孔缝对电磁屏蔽效能的影响

汽车正在逐步走向电子化,只有处理好汽车上电子设备的电磁兼容（EMC）问题,才能更好地运用电子设备。本文主要针对汽车上几种规则孔缝的电磁泄漏进行建模、理论分析和仿真分析,得出一个屏蔽效能（SE）较高的模型,从而有效地降低了汽车的电磁辐射和提高了本身的抗电磁干扰能力。并对某一款式的轿车进行了电磁屏蔽设计,使其电磁屏蔽效能提高了8dB。从而验证了本文电磁屏蔽设计方法的有效性。     

Über eine neue Methode der Messung sehr kleiner Mengen von CO in Luft,Blut und Lunge

Summary We have developped a new method to detect and measure very small amounts of CO having a sensitivity of 1 p. CO per 100 million p. air. HgO is heated in an oven reaction chambre where it reacts with CO in releasing proportional amounts of mercury vapor; the latter is then measured quantitatively in an UV electronic spectrophotometer. Reaction chamber and UV meter are assembled into a handy portable unit. The CO amount in blood is measured by decomposing a sample of blood in a volumetric flask with H₂SO₄ and drawing the gas mixture through the unit. The CO amount in alveolar air is measured by means of breathing bags. It is thus possible to study the influence of subtoxic doses of CO and the cancerogenic action of tobacco smoking.     

Light transmission. I. An acoustic method able to monitor transmitted light

Summary A method able to monitor transmitted light acoustically is described. It makes use of an amplifier of light variations, provided with a photocell and a sound device, a photometer, an optic probe and a special support.Acknowledgments. The author would like to thank Dr Leonard Salzarulo, chairman of the Physics Department of the New Jersey Institute of Technology, for the critical reading of the paper. The author acknowledges the invaluable assistance of Prof. Araldo Ramundo of the Centro Regionale Professionale in Cosenza, Italy, for designing and assembling the electronic amplifier. Appreciation is also extended to Prof. Giuseppe Battendieri of the Liceo Scientifico Enrico Fermi in Cosenza, Italy, for the schematic reproduction of the apparatus.     

Continuous registration of X,Y-coordinates and angular position in behavioural experiments

Summary An electronic camera and 2 simple additional circuits for the registration of the X, Y-coordinates or the angular position of animals in behavioural experiments are described.     

压电陶瓷变压器的研究进展

压电陶瓷变压器是一种新型固态电子器件,具有高转换效率、高能量密度、结构简单、体积小、无电磁噪声的特点,在电子产品微型化的过程中起到了十分重要的作用。本文回顾了压电陶瓷变压器的发展历史,阐述了压电陶瓷变压器的基本工作原理,介绍了压电陶瓷变压器所用的新型压电材料、振动模式和几何结构、外围电路三大方面的最新研究进展。通过对比国内外在压电变压器领域的研究和应用现状,指出了我国发展压电变压器的优势和前景,并提出了压电变压器产业的发展方向。     

多孔硅发光中的极化子效应

多孔硅体现了许多新光学性质，本文通过温度依赖的发光，傅立叶红外谱，时间分辨红外谱的观察。发现了些有规律的信息。众所周知，多孔硅在空气中陈化氧化，导致内部纳米尺寸减小。界面层由氢变为氧，我们发现同时伴随着电子态从本征态向极化子态的变化，前者随尺寸减小能量升高，表现为正常的量子限域效应。而后者却随尺寸减小能量降低。表现为量子限域极化子效应。温度依赖的发光谱型和强度变化也清楚地反映了尺寸依赖的极化子行为。因此，我们提出了个基本的物理模型来描述多孔硅中增强的极化子尺寸效应及其光学行为。     

The 'Hyperbola of Quantum Chemistry': the Changing Practice and Identity of a Scientific Discipline in the Early Years of Electronic Digital Computers, 1945-65

In 1965, John A. Pope presented a paper entitled 'Two-Dimensional Chart of Quantum Chemistry' to illustrate the inverse relationship between the sophistication of computational methods and the size of molecules under study. This chart, later called the 'hyperbola of quantum chemistry', succinctly summarized the growing tension between the proponents of two different approaches to computation–the ab initio method and semiempirical method–in the early years of electronic digital computers. Examining the development of quantum chemistry after World War II, I focus on the role of computers in shaping disciplinary identity. The availability of high-speed computers in the early 1950s attracted much attention from quantum chemists, and their community took shape through a series of conferences and personal networking. However, this emerging community soon encountered the problem of communication between groups that differed in the degree of reliance they placed on computers. I show the complexity of interactions between computing technology and a scientific discipline, in terms of both forming and splitting the community of quantum chemistry.     

Formation of microspheres from simple molecules under simulated primitive earth conditions; ultrasound and light radiation

Summary We have synthesized microspheres from aqueous solutions of simple molecules submitted to sonolysis at 20 kHz and 800 kHz in an argon atmosphere. Photochemical reaction under room light or UV-irradiation yielded the same microstructures, whose formation has been studied with optical and electronic microscopes.     

基于Multisim10的RLC串联电路频率特性仿真测试

Multisim10是电子电路仿真实验中广泛应用的理想工具。本文以Multisim10为平台,对RLC串联电路进行了必要的仿真、测试,分析了其幅频特性、相频特性,提出了提高电路选频作用的方法。     

应用于微结构制造自治系统的结构描述语言

本文介绍一种微结构描述语言。借助于这种描述语言，包括集成电路、MEMS等在内的各类微、纳尺寸的器件，都能够得到描述并借此进入微结构制造自治系统。微结构制造自治系统是我所提出的一种概念性系统，意指具备一定的智能，能够应对多种制造过程突发情况的全自动化的集成电路无人制造系统。系统在获得特定加工对象的结构描述之后，可对结构进行分析，提取结构特征并自动生成加工制造工艺。本文结合一个CMOS结构实例，介绍了所定义的微结构描述语言的各项先进特性。这方面研究工作的重要意义在于，每个微结构器件，包括将要被发明的，可视为微结构描述语言所能够描述的对象集中的一个特例，从而得到统一的分析与处理。结构特征的分析，为接下来的工艺流程自动生成工作搜集和准备了必要的结构信息。