New measurement and evaluation of the excitation function of Ni(p,n) reaction for the production of Cu

One of the radioisotopes for which a growing interest exists in nuclear medicine is ⁶⁴Cu. Its branched decay makes it suitable for both diagnostic and therapeutic purposes. Activation cross sections of the proton induced reaction on enriched ⁶⁴Ni have been studied using the stacked foil technique up to 24 MeV. The experimental cross sections are compared with values available from literature. Thick target yields, based on the discrete measured values of the cross sections are calculated and allow a better estimation of the optimum production parameters.     

Swift iodine ion modification of the structural and magnetotransport properties of Fe/Cr systems

Fe/Cr/Fe trilayers and (Fe/Cr)₂₀ multilayers prepared under ultrahigh vacuum conditions by thermal evaporation were irradiated with 200 MeV I¹³⁺ ions in the fluence range between 1 × 10¹¹ and 8 × 10¹² I/cm². The structural properties of the Fe/Cr/Fe trilayers and (Fe/Cr)₂₀ multilayers were measured by X-ray reflectivity (XRR) and conversion electron Mössbauer spectroscopy (CEMS). Magnetic exchange coupling between the Fe layers through the Cr spacer layer was observed by SQUID magnetization measurements. Magnetoresistance effect was measured using four probe method at room temperature. The XRR spectra showed an increase of the interface roughness versus increasing irradiation fluence in the multilayers, while in the trilayers smoothening of the interfaces in the sample irradiated with fluence equal to 4 × 10¹¹ I/cm² and very slight change for other fluences were observed. Improving of the interface structure in the trilayers at this fluence was observed also by CEMS. Moreover the Mössbauer spectra also confirm roughening of the interfaces as a function of fluence for multilayers. Before irradiation an antiferromagnetic coupling fraction dominated in all samples. After irradiation the changes of magnetic coupling were different in both types of samples. The trilayers were less sensitive to the irradiation fluence than multilayers and an increase of the antiferromagnetic fraction at small fluences was observed. In the multilayers a continuous decrease of the antiferromagnetic fraction as a function of fluence was evidenced. Vanishing of the antiferromagnetic coupling, observed for the largest fluence, resulted in the decrease of magnetoresistance effect in the Fe/Cr multilayers.     

基于C／C＋＋与ORACLE9i的嵌入式SQL编程技术

针对嵌入式SQL编程技术，本文论述了C/C 语言与ORACLE9i的嵌入式SQL的形式，嵌入式SQL语句与C／C 宿主语言之间的通信．并给出了代码实例。     

WLAN安全技术方案探析

无线局域网(WLAN)技术的发展使人们摆脱了传统线缆的束缚,可以更加方便、灵活、快捷地访问网络资源。但空间的开放性使无线局域网的安全受到来自外部入侵的威胁,安全方案已经成为无线网络发展的瓶颈。本文讨论了无线网络发展过程中的几种主要的安全方案,重点研究802.11i标准中采用的核心的加密方案WPA。     

基于C/C++与ORACLE9i的嵌入式SQL编程技术

The programming technology about Embedded SQL discuss the form of Embedded SQL base on C/C language and ORACLE9i DBMS in this paper. We have also discussed the communications between the sentence of Embedded SQL and C/C language and have provided the code.     

Making XML document markup international

In name and in practice, the World‐Wide Web (hereafter Web) is used around the World beyond English‐speaking areas. This creates a tremendous need to internationalize standard terminology used in the technologies that make the Web possible. Existing efforts on XML internationalization (i18n) and localization (i10n) have focused on the content of XML documents instead of the terms used in markup (annotations) such as elements and attributes. The SGML standard ISO 8879 supports the use of Unicode (ISO 10646) throughout a document, including markups. However, most elements and attributes of XML documents are still defined in English, thereby limiting their use among non‐English speakers. This paper presents an XSLT‐based method that can completely localize the markup of XML documents into different natural languages. We also describe how the proposed technique can be applied to translation problems in programming (e.g. C and Java) or documentation (e.g. LAT_EX or other formatting languages) so that a program or a document can be converted to and from an XML format. Copyright © 2004 John Wiley & Sons, Ltd.     

AB SLC500系统在河南油田三次采油中的应用

河南油田三次采油应用AB SLC500系统实现了全过程监控。详细介绍了系统工艺流程、控制系统方案、软硬件配置,阐述了AB远程I/O技术的实现以及系统软件的设计。实践证明该系统的成功运用提高了三次采油的自动化水平和经济效益。     

Neural Networks Approach to the Random Walk Dilemma of Financial Time Series

Predictions of financial time series often show a characteristic one step shift relative to the original data as in a random walk. This has been the cause for opposing views whether such time series do contain information that can be extracted for predictions, or are simply random walks. In this case study, we show that NNs that are capable of extracting weak low frequency periodic signals buried in a strong high frequency signal, consistently predict the next value in the series to be the current value, as in a random walk, when used for one-step-ahead predictions of the detrended S&P 500 time series. In particular for the Time Delay Feed Forward Networks and Elman Networks of various configurations, our study supports the view of the detrended S&P 500 being a random walk series. This is consistent with the long standing hypothesis that some financial time series are random walk series.     

The Monte Carlo Event Generator AcerMC version 1.0 with interfaces to PYTHIA 6.2 and HERWIG 6.3

The AcerMC Monte Carlo Event Generator is dedicated for the generation of Standard Model background processes at pp LHC collisions. The program itself provides a library of the massive matrix elements and phase space modules for generation of a set of selected processes: , , , , and complete electroweak process. The hard process event, generated with one of these modules, can be completed by the initial and final state radiation, hadronization and decays, simulated with either PYTHIA or HERWIG Monte Carlo event generator. Interfaces to both of these generators are provided in the distribution version. The matrix element codes have been derived with the help of the MADGRAPH package. The phase-space generation is based on the multi-channel self-optimizing approach as proposed in NEXTCALIBUR event generator. Eventually, additional smoothing of the phase space was obtained by using a modified ac-VEGAS routine in order to improve the generation efficiency.     

Effects of ion beam treatment on atomic and macroscopic adhesion of copper to different polymer materials

Low-energy ion irradiation of polymer induces different phenomena in the near surface layer, which effect strongly the metal-polymer interface formation and promotes adhesion of polymers to metals. Low-energy argon and oxygen ion beams were used to alter the chemical and physical properties of different polymers (PS (polystyrene), PαMS (poly(α-methylstyrene), BPA-PC (bisphenol-A-polycarbonate) and PMMA (poly(methyl methacrylate)), in order to understand the adhesion phenomena between a deposited Cu layer and the polymers. The resulting changes were investigated by various techniques including X-ray photoelectron spectroscopy, measurements of the metal condensation coefficient and a new technique to measure cross-linking at the polymer surface. Two types of practical adhesion strengths of Cu-polymer systems, measured using 90° peel tests, were observed: (i) peel strength increased at low ion fluences, reached a maximum and then decreased after prolonged treatment and (ii) no improvement in the peel strength on treated polymer surfaces was recorded. The improvement in the metal-polymer adhesion in the ion fluence range of 10¹³-10¹⁵ cm⁻² is attributed to the creation of a large density of new adsorption sites resulting in a larger contact area and incorporation of chemically active groups that lead to increased interaction between metal and polymer by metal-oxygen-polymer species formation. XPS analysis of peeled-off surfaces showed that in most cases the failure location changed from interfacial for untreated polymers to cohesive failure in the polymer for treated surfaces. These observations and measurements of the metal condensation coefficients suggest that bonding is improved at the metal-polymer interface for all metal-polymer systems. However, the decrease in the peel strength at high ion fluences is attributed to the formation of a weak boundary layer in polymers. The correlation between sputter rate of polymers and altering in the peel strength for moderate ion fluences was determined. It was observed that the metal-polymer adhesion could be improved for PS and BPA-PC, which have a low sputter rate and preferentially formed cross-links in the treated surface. For degrading polymers, like PαMS and PMMA, chain scission rather than cross-linking dominates, low molecular weight species are formed and no adhesion enhancement is observed.