Radiation chemical reactions of poly-p-chlorphenylmethacrylate by ESCA

Summary ESCA is used to characterize ion beam irradiated P(p-ClPhMA)-samples. The results show a chlorine abstraction. The experimental findings are in accordance with a recently proposed model for a crosslinking mechanism of halogenated aromatic polymers.     

真空热处理工艺参数的选取

通过多种材料、多种工件、多批次的加工，对常见真空热处理工艺参数的确定，摸索出一些经验公式，并在实际生产中取得很好效果。     

Video tape manufacture by high vacuum evaporation—aspects of machine technology

The next generation of video tapes will use evaporated thin films with their superior properties such as recording density, output level, frequency characteristics and signal-to-noise ratio. This paper describes the metal layer formation by a simple model for the growth of microcolumns at oblique incidence deposition. The most relevant process parameters are discussed. The layout of a production coater is described.     

Damage and strain in pseudomorphic vs relaxed GexSi1−x layers on Si(100) generated by Si ion irradiation

We compare both the strain and damage that 100 keV Si irradiation at room temperature introduces in pseudomorphic and relaxed Ge_xSi_1−x films grown on Si(100) substrates. The ion range is such that the Si/Ge_xSi_1−x interface is not significantly damaged. The amount of damage produced in pseudomorphic and relaxed Ge_xSi_1−x layers of similar x for irradiation doses up to 2.5 × 10¹⁴ Si/cm² is the same, which proves that a pre-existing uniform strain does not noticeably affect the irradiation-induced damage. However, the irradiation-induced strain does depend on the pre-existing strain of the samples. Possible interpretations are discussed. On leave from Inst. voor Kern en Stralingsfysika, Catholic University of Leuven, Belgium.     

Towards hybrid Triple Helix indicators: A study of university-related patents and a survey of academic inventors

This paper presents work directed at capturing the entrepreneurial and collaborative activity of university researchers. The Triple Helix points to the emergence of the entrepreneurial university as well as to an increasing overlay of activities in universities, industry and government. This study explores ways in which patent-based metrics could be utilized in a Triple Helix context, and how hybrid indicators could be developed by combining patent with survey data. More specifically, it aims to develop indicators that connect technological inventiveness of university researchers to both funding organizations and users, as well as to entrepreneurial activities by academics. The paper develops a simplified model of the innovation process to benchmark the relevance of the indicators to the Triple Helix. An analysis of Finnish academic patents illustrates that patent data can already provide useful indicators but, on its own, cannot provide information about how academic patents are interconnected with government or industry through funding or utilization links. An exclusive analysis of patents can point to patent concentrations on certain universities, to inventors and assignees, or to potential gaps in translating applied science into industrial technology. However, the patent data had to be combined with an inventor survey in order to relate academic patents more to their Triple Helix environment. The survey indicated that most patented academic inventions are connected to (often publicly funded) scientific research by the inventors and tend to be utilized in large firms rather than in start-up companies founded by academic entrepreneurs.     

Application of singular value decomposition on FDTD simulation result - a novel approach for modal analysis of complex electromagnetic problems

We have proposed that application of singular value decomposition on finite-difference time-domain simulations is best suited for modal analysis of complex real-life electromagnetic problems. This combination of two powerful techniques yields a wealth of information about the complete mode structure which cannot be otherwise obtained. This is particularly important for a real-life system having complex geometry and consisting of a range of materials from good conductors to dielectrics and this is further complicated by the existence of broad-band excitation. This hybrid approach is versatile, accurate, and computationally efficient.     

Modeling of microwave-excited gas discharges

Content This paper is dealing with the power density versus electric field characteristic of microwave-excited discharges on the example of typical CO₂ laser gas discharges.The fundamentals of the method are a simple electric equivalent circuit for the excitation structure and the assumption of a fixed reduced electric field intensity within the plasma. This operating field is enforced by the plasma under stationary conditions and can be calculated using an electron balance under consideration of the non-Maxwellian electron energy distribution function. The calculations turn out that c.w. excitation with microwaves is involved with considerable plasma power densities. In the case of the CO₂ laser this requires special discharge channel designs for effective gas cooling. Besides a discussion of the plasma characteristic, measurements taken from a microwave applicator are presented and compared to the calculations.

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Modellierung mikrowellenangeregter Gasentladungen

Übersicht Der Artikel behandelt die Berechnung der Feldstärke-Leistungsdichte-Kennlinie mikrowellenangeregter Gasentladungen am Beispiel von Entladungen in typischen CO₂-Lasergasgemischen. Das Berechnungsverfahren beruht auf einem einfachen, auf die meisten Anregungsstrukturen anwendbaren elektrischen Ersatzschaltbild und der Tatsache einer vom Plasma erzwungenen stationären Brennfeldstärke. Letztere wird über eine Elektronenbilanz unter Berücksichtigung der nicht Maxwell'schen Elektronen-Energieverteilung ermittelt. Es zeigt sich, daß bei einer CW-Anregung mit Mikrowellen hohe Mindestleistungsdichten im Plasma auftreten, wodurch beispielsweise im Fall des CO₂-Lasers kein Laserbetrieb ohne sehr effektive Maßnahmen zur Gaskühlung möglich ist.Neben einer Diskussion der Plasmakennlinie werden Vergleichsmessungen an einer konkreten Anregungsstruktur vorgestellt.

     

Relationship between Relaxation Internal Friction Peak at about 200℃(f≈1Hz)and Bainitic Transformation In a CuZnAl Alloy

The present investigation showed that the re-laxation peak at about 200℃ (f≈1Hz) was relatedto bainitic transformation in a CuZnAl alloy.Thepeak decreased when bainite precipitated.Theactivation energy of the peak was the same as theapparent activation energy of bainitic transforma-tion.According to the relations between the peakand the bainitic transformation,the mechanism ofthe peak has been discussed.     

Formation of droplets on Si surfaces bombarded by In from a capillary type liquid metal ion source

Droplet formation on Si surfaces bombarded by 10 keV beams from a liquid metal indium ion source has been observed. It has been verified that excess indium is transported in the ion beam, probably in the form of charged droplets. SIMS, SEM and RBS techniques have been used to study the distribution of droplets at the surface. At the specified ion source operating conditions, equilibrium droplet coverage is of the order of 25%. Individual droplets have an average diameter of 0.35 ωm and an average height of 2.2 nm. At a bombardment current density of 0.1 mA cm^?2, equilibrium coverage is reached in about 1 s.     

On the Mechanism of Palladium(0)-Catalyzed Reactions of Allylic Substrates with Nucleophiles. Origin of the Loss of Stereospecificity

The mechanism of the loss of stereospecificity in palladium-catalyzed nucleophilic substitution of allylic substrates has been investigated. Eight substrates (cis and trans isomers of 1a-d) and two nucleophiles (Et₂NH and NaCH(SO₂Ph)₂) were studied. In the animation reactions two pathways are responsible for the formation of anomalous inversion product, viz., isomerization of the starting material (path B, Scheme 2) and isomerization of the π-allyl intermediate via displacement of palladium by Pd(0) (path C, Scheme 2), the latter of which predominates. In the alkylation the results indicate that loss of stereospecificity is caused only by path C. The use of a more reactive substrate increased the stereospecificity of the reaction and suppressed the isomerization pathway. An analysis of the kinetics is consistent with the hypothesis that path C is the major pathway for the stereochemical loss.