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91.
A sub-sea deployable fiber-optic sensor system for the continuous determination of a range of environmentally relevant volatile organic compounds in seawater has been developed. The prototype of a robust, miniaturized Fourier transform infrared (FT-IR) spectrometer for in situ underwater pollution monitoring was designed, developed, and built in our research group. The assembled instrument is enclosed in a sealed aluminium pressure vessel and is capable of maintenance-free operation in an oceanic environment down to depths of at least 300 m. The whole system can be incorporated either in a tow frame or a remotely operated vehicle (ROV). A suitable fiber-optic sensor head was developed, optimized in terms of sensitivity and hydrodynamics, and connected to the underwater FT-IR spectrometer. Due to a modular system design, various other sensor head configurations could be realized and tested, ensuring facile adaptation of the instrument to future tasks. The sensor system was characterized in a series of laboratory and simulated field tests. The sensor proved to be capable of quantitatively detecting a range of chlorinated hydrocarbons and monocyclic aromatic hydrocarbons in seawater down to the low ppb (microg/L) concentration range, including mixtures of up to 6 components. It has been demonstrated that varying amounts of salinity, turbidity, or humic acids, as well as interfering seawater pollutants, such as aliphatic hydrocarbons or phenols, do not significantly influence the sensor characteristics. In addition, the sensor exhibits sufficient long-time stability and a low susceptibility to sensor fouling. 相似文献
92.
This paper reports on progress on the feasibility of fabricating molds for electroplating of medium-to-high aspect ratio structures (up to 5) using SPR 220-7 positive photoresist, commercialized by Shipley [1, 2]. We used this photoresist as an alternative to SU-8 negative epoxy-based photoresist, which is very difficult to process and remove after electroplating [3, 4]. SPR 220-7 is easy to work with and can be used as a sacrificial layer if removed after processing. A single layer of SPR 220-7 was deposited by spin coating up to 18 m thickness. Thicker layers (34–54 m) can be achieved with multi-layer coating/baking steps using a manual spin coater and oven. The motivation of this work is to realize micromachined high-density current-carrying wires for atom guides [5, 6]. However, the process can be used for a variety of applications such as on-chip inductors and microtransformers. 相似文献
93.
Kraft E. Fischer P. Karagounis M. Koch M. Krueger H. Peric I. Wermes N. Herrmann C. Nascetti A. Overdick M. Ruetten W. 《IEEE transactions on nuclear science》2007,54(2):383-390
A novel signal processing concept for X-ray imaging with directly converting pixelated semiconductor sensors is presented. The novelty of this approach compared to existing concepts is the combination of charge integration and photon counting in every single pixel. Simultaneous operation of both signal processing chains extends the dynamic range beyond the limits of the individual schemes and allows determination of the mean photon energy. Medical applications such as X-ray computed tomography can benefit from this additional spectral information through improved contrast and the ability to determine the hardening of the tube spectrum due to attenuation by the scanned object. A prototype chip in 0.35-micrometer technology has been successfully tested. The pixel electronics are designed using a low-swing differential current mode logic. Key element is a configurable feedback circuit for the charge sensitive amplifier which provides continuous reset, leakage current compensation and replicates the input signal for the integrator. This paper will discuss measurement results of the prototype structures and give details on the circuit design 相似文献
94.
Online services and applications extend the influencing opportunities of traditional word-of mouth (WOM). Unlike traditional word-of-mouth, the online environment allows for special features such as anonymity in user-generated content. Furthermore, the personality of online users affects their motivation when creating this content. The aim of this paper is to link specific online activities, i.e., the posting of product ratings and participation in discussions in online forums, with certain personality traits within an empirical study. The findings, based on an online survey with more than 16,900 completed questionnaires, indicate that opinion leaders in the online environment cannot be compared with traditional opinion leaders in terms of their articulation and personality structure. In regard to online activities with a high influencing potential, the results of moderated regression analyses show that persons with an introverted personality are more active as online opinion leaders due to the lack of social recognition they experience. The results have implications for how marketers should present incentive structures to address and integrate potential online opinion leaders, and how scholars should understand the role of opinion leaders in the online environment. 相似文献
95.
We have used transgenic tobacco seeds to produce large amounts of a functionally active engineered antibody. A gene infusion encoding an antigen-binding single chain Fv protein (scFv) that recognizes the hapten oxazolone was constructed and used as a model. After characterization in a bacterial expression system ,the scFv gene was cloned into a plant expression cassette conferring seed specific expression, and transferred using Agrobacterium-mediated transformation, into Nicotiana tabacum. The expressed scFv could be detected in the developing as well as ripe seeds of regenerated transgenic plants, and the functionally active scFv is stabaly deposited and accumulates up to 0.67% of the total soluble seed protein. After storage of ripe transgenic tobacco seeds for one year at room temperature there was no loss of scFv protein or its antigen-binding activity. 相似文献
96.
In order to partition indigestible N in heat-damaged forages into its various chemical fractions, alfalfa (41.1% dry matter), stored in an upright stave silo, was not sealed, and heating was promoted. Silage was labeled as unheated silage (temperature below 20 degrees C); 35 degrees C silage (temperature near 35 degrees C, 5220 degrees C d); and 60 degrees C silage (temperature near 60 degrees C, 10,800 degrees C d). Total amino acid content of 60 degrees C silage was lower and acid detergent insoluble amino acid content was higher than in 35 degrees C or unheated silages. Apparent N digestibilities, determined using lactating dairy cows, were 47.5, 48.4, and 63.6% for 60 degrees C, 35 degrees C, and unheated silages. Estimates of true N digestibility were 76, 76, and 90%; true digestibility coefficients for amino acid N were 86, 92, and 95%; and true digestion coefficients for nonamino acid N were 67, 45, and 69% for 60 degrees C, 35 degrees C, and unheated silages. Two possible causes for depressed N digestibility of 60 degrees C silage were 1) the ratio of poorly digested nonamino acid N to highly digested amino acid N was higher in 60 degrees C silage than in 35 degrees C or unheated silage, and 2) amino acid N in 60 degrees C silage was digested less than amino acid N in 35 degrees C or unheated silage. Reasons for low digestibility of N in 35 degrees C silage are less clear, but evidence suggests formation of indigestible N complexes in digesta. 相似文献
97.
98.
Yvonne Conrad 《Datenschutz und Datensicherheit - DuD》2006,30(7):405-409
Zusammenfassung Der Wandel der Gesellschaft im Umgang mit personenbezogenen Daten sowie die stete Entwicklung technischer M?glichkeiten in
der Datenverarbeitung haben l?ngst dazu beigetragen, dass Verbraucherinnen und Verbraucher im Wege der Erstellung umfassender
Konsumentenprofile immer st?rker in die Rolle gl?serner Kunden gedr?ngt werden. Daten sammelnde Unternehmen stellen insoweit
eine Gefahr für das Recht der Einzelnen auf informationelle Selbstbestimmung dar. Vor diesem Hintergrund befasst sich der
Beitrag mit den datenschutzrechtlichen Anforderungen an Kundenbindungsprogramme und zeigt, wie sie datenschutzgerecht und
verbraucherfreundlich gestaltet werden k?nnen. 相似文献
99.
MK Kraft AB Rothbard TR Hadley AT McLellan DA Asch 《Canadian Metallurgical Quarterly》1997,154(9):1214-1219
OBJECTIVE: Previous research has suggested that support services supplementing methadone maintenance programs vary in their cost-effectiveness. This study examined the cost-effectiveness of varying levels of supplementary support services to determine whether the relative cost-effectiveness of alternative levels of support is sustained over time. METHOD: A group of 100 methadone-maintained opiate users were randomly assigned to three treatment groups receiving different levels of support services during a 24-week clinical trial. One group received methadone treatment with a minimum of counseling, the second received methadone plus more intensive counseling, and the third received methadone plus enhanced counseling, medical, and psychosocial services. The results at the end of the trial period have been published elsewhere. This article reports the results of an analysis at a 6-month follow-up. RESULTS: The follow-up analysis reaffirmed the preliminary findings that the methadone plus counseling level provided the most cost-effective implementation of the treatment program. At 12 months, the annual cost per abstinent client was $16,485, $9,804, and $11,818 for the low, intermediate, and high levels of support, respectively. Abstinence rates were highest, but modestly so, for the group receiving the high-intensity, high-cost methadone with enhanced services intervention. CONCLUSIONS: This study suggests that large amounts of support to methadone-maintained clients are not cost-effective, but it also demonstrates that moderate amounts of support are better than minimal amounts. As funding for these programs is reduced, these findings suggest a floor below which supplementary support should not fall. 相似文献
100.