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81.
We extend the work of the first two papers in this series [Appl. Opt. 50, 4998-5011 (2011), Appl. Opt. 50, 5012-5022 (2011)] to design compound prisms for linear-in-wavenumber dispersion, especially for application in spectral domain optical coherence tomography (OCT). These dispersive prism designs are believed to be the first to meet the requirements of high resolution OCT systems in direct-view geometry, where they can be used to shrink system size, to improve light throughput, to reduce stray light, and to reduce errors resulting from interpolating between wavelength- and wavenumber-sampled domains. We show prism designs that can be used for thermal sources or for wideband superluminescent diodes centered around wavelengths 850, 900, 1300, and 1375 nm. 相似文献
82.
Hermann Hagen 《Forschung im Ingenieurwesen》1966,32(5):142-146
Zusammenfassung Für eine Axialverdichterstufe wird die Verdichterkennlinie unter Berücksichtigung der Kompressibilit?t berechnet und in einem
Beispiel ein Fall mit vereinfachten Annahmen und verlustloser Gitterstr?mung einem anderen Fall unter Berücksichtigung gemessner
Gitterbeiwerte und gemessener Verluste gegenübergestellt. Die Kennlinien für den Verlauf der Druckzahl über der Durchflu?zahl
h?ngen erheblich von der Lavalzahl der Umfangsgeschwindigkeit ab. Für das Hauptarbeitsgebiet der Stufe tritt der Einflu? der
zunehmenden Lavalzahl der Umfangsgeschwindigkeit bei der Rechnung in gleicher Weise zutage wie es von gemessenen Stufenkennlinien
her bekannt ist. Bei der Durchrechnung von Gitterelementen einer Stufe auf dem angegebenen Weg dürfte es m?glich sein, eine
günstige Abstimmung zu finden.
Der Verfasser dankt der Firma M. A. N. Turbo GmbH, München-Allach, für die Zustimmung zur Ver?ffentlichung. 相似文献
83.
In this work, the stability of the Economic Simplified Boiling Water Reactor (ESBWR) has been studied by using a Freon-134a based experimental facility (GENESIS) and two system codes, being ATHLET 2.0a and (to a lesser extent) TRACG. During setting up the GENESIS facility and the numerical calculations, a great effort has been made to approximate the ESBWR system as accurate as possible.In general, it was found that a sufficient margin to instability exists regarding the ESBWRs nominal point. In addition, a comparison was made between the numerical and experimental results for both the thermal-hydraulic system and the reactor system. Deviations were found between the numerical and experimental results, in spite of the close similarity between the GENESIS facility and the definition of the ESBWR system in the system code. This result shows that predictions regarding real nuclear reactors, based on modeled systems, should be taken with care. 相似文献
84.
K. Nagy J.L. Kloosterman D. Lathouwers T.H.J.J. van der Hagen 《Annals of Nuclear Energy》2011,38(2-3):601-609
The molten salt reactor (MSR) is an attractive breeder reactor. A graphite-moderated MSR can reach breeding because of the online salt processing and refueling. These features give difficulties when the breeding gain (BG) of the MSR is evaluated. The inventory of the core and external stockpiles have to be treated separately in order to quantify the breeding performance of the reactor. In this paper, an improved BG definition is given and it is compared with definitions used earlier. The improved definition was used in an optimization study of the graphite – salt lattice of the core. The aim of the optimization is a passively safe, self-breeder reactor. The fuel channel diameter, graphite volume and thorium concentration were varied while the temperature feedback coefficient of the core, BG – as defined in the paper – and the lifetime of the graphite were calculated. There is a small range of lattices which provide both negative temperature feedback and breeding. Furthermore, breeding is possible only at low power densities in case of the salt processing efficiencies set in this study. In this range of power the lifetime of the graphite is between 12 and 20 years. 相似文献
85.
Co-injection of the parasite Onchocerca ochengi and the caspase inhibitors z-VAD.fmk and boc-D.fmk into the natural vector Simulium damnosum s.l. led to significantly increased survival of the parasites. Subsequent in situ apoptosis detection assays demonstrated that in the case of boc-D.fmk the enhanced survival was due to a diminished apoptosis level of the microfilariae in vivo. Additional assays using O. ochengi microfilariae which were coinjected with serine protease inhibitors into S. damnosum s.l. revealed that certain serine protease inhibitors can reduce the level of apoptosis. 相似文献
86.
J. L. Kloosterman H. van Dam T. H. J. J. van der Hagen 《Nuclear Engineering and Design》2003,222(2-3):105
Burnup calculations have been performed on a standard HTR fuel pebble with a radius of 3 cm containing 9 g of 8% enriched uranium and burnable poison particles (BPP) made of B4C highly enriched in 10B. The radius of the BPP and the number of particles per fuel pebble have been varied to find the flattest reactivity-to-time curve. It was found that for a k∞ of 1.1, a reactivity swing as low as 2% can be obtained when each fuel pebble contains about 1070 BPP with a radius of 75 μm. For coated BPP that consist of a graphite kernel with a radius of 300 μm covered with a B4C burnable poison layer, a similar value for the reactivity swing can be obtained. Cylindrical particles seem to perform worse. In general, the modification of the geometry of BPP is an effective means to tailor the reactivity curve of HTRs. 相似文献
87.
Conclusion The model presented above covers the basic physical and chemical processes in synthesis of polyesters. It describes the method with DMT and TPA in a wide range of parameters and compositions and simultaneously considers the processes in the final reactor. The model is a tool for optimizing the parameters of the process and designing reactors and thus deepens knowledge concerning synthesis of polyesters. It points out the path to new technical solutions, improving the conditions of the process, increasing the economy and output, and improving product quality.It was possible to decrease the number of reactors for Karl Fisher's continuous method of production of PET to four based on the parameters of the process conducted in existing installations and model calculations. For the method calculated for three reactors [5, 6], the model has serious drawbacks with respect to product quality, economy, and flexibility of the installations, which probably restrict the use of such a system to lower-quality products.In addition, the model provides for increasing the individual line output from 180–200 tons/day to 300 or even 400 tons/day.Translated from Khimicheskie Volokna, No. 4, pp. 9–14, July–August, 1994. 相似文献
88.
We report the results of a questionnaire sent to anaesthetists and midwives on the use of obstetric analgesia and anaesthesia in Norwegian hospitals in 1996. 95% of the 49 hospitals involved responded to the questionnaire, representing a total of 56,884 births. The use of epidural analgesia in labour varied from 0 to 25% in the different hospitals with a mean value of 15%. Epidural analgesia was much more widely used in university and regional hospitals than in local hospitals (p < 0.001). Five of the local hospitals did not offer epidural analgesia during labour at all. The combination of low-dose local anaesthetic and an opioid (either sufentanil or fentanyl) had not been introduced in nine of the hospitals (20%). The optimal use of epidural analgesia to relieve labour pain was judged to be more frequent by the anaesthetists than by the midwives (19% versus 11%, p < 0.01). In response to what factors limited the frequency of epidural analgesia, the anaesthetists specified factors related to the attitude of the midwife, and the midwives specified factors related to the anaesthetist. Only five of the hospitals provided written information on the various analgesic methods that could be employed during labour. The majority of midwives considered the analgesic methods employed on their maternity ward to be good or excellent. The frequency of Caesarean section was 12%; spinal anaesthesia was used in 55%, epidural anaesthesia in 17%, and general anaesthesia in 28% of the cases. 相似文献
89.
MP Ritter JH Peters TR DeMeester M Gadenst?tter S Oberg M Fein JA Hagen PF Crookes CG Bremner 《Canadian Metallurgical Quarterly》1998,133(5):523-8; discussion 528-9
OBJECTIVE: To examine the factors affecting outcome in patients with advanced gastroesophageal reflux disease. DESIGN: Retrospective analysis. SETTING: University tertiary referral center. PATIENTS: Thirty-seven patients with advanced gastroesophageal reflux disease and no previous antireflux surgery. INTERVENTIONS: Thirty patients underwent Collis gastroplasty for esophageal lengthening and Belsey partial fundoplication. Seven patients with esophageal stricture and global loss of esophageal body motility who underwent primary esophagectomy and reconstruction were used as a comparison group. OUTCOME MEASURES: Symptomatic outcome in all 37 patients was assessed by questionnaire at a median of 25 months (range, 5-156 months) after surgery. In a subset of 11 patients undergoing the Collis-Belsey procedure, outcome was measured using 24-hour pH and results of motility studies. RESULTS: The Collis-Belsey procedure was successful in relieving symptoms of gastroesophageal reflux in 21 (70%) of the 30 patients. The outcome was excellent or good in 16 (89%) of 18 patients who presented with symptoms other than dysphagia, but only in 5 (42%) of 12 patients with dysphagia (P = .01). The outcome was particularly poor if dysphagia was associated with a previously dilated esophageal stricture. Persistent or induced dysphagia was the reason for failure in all but 1 patient. Results of 24-hour esophageal pH studies were returned to normal in 8 (73%) of 11 patients undergoing postoperative evaluation. Contraction amplitudes in the distal esophagus and the prevalence of simultaneous contractions in these segments did not change after the operation. All 7 patients who underwent primary esophagectomy were classified as having an excellent or good outcome and were relieved of their reflux symptoms, including dysphagia. Six of these could eat 3 meals per day and enjoyed an unrestricted diet. CONCLUSIONS: The outcome of the Collis-Belsey procedure in patients with advanced gastroesophageal reflux disease without dysphagia is excellent. It is less so in patients with dysphagia as a preoperative symptom. Esophagectomy can provide a good outcome in patients who have a combination of dysphagia stricture and a profound loss of esophageal motility. 相似文献
90.
W. Postel F. Drawert und W. Hagen 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1973,150(5):267-273
Zusammenfassung In 99 Weinen wurde der Gehalt anl(+)- undd(–)-Lactat enzymatisch bestimmt. Die in der Literatur vorgeschlagene alkalische Verseifung des Weins darf nicht durchgeführt werden, da dies zu stark fehlerhaften Ergebnissen durch die Bildung von Milchsäure aus dem Restzucker der Weine führt. Auf einen Aufschluß durch Säure oder durch Kochen kann verzichtet werden, da die gebundene Menge an Milchsäure im Wein nur zu maximal 100–200 mg/l festgestellt wurde. Wenn nur der Gesamtlactatgehalt interessiert, so kann dieser ebenfalls enzymatisch ohne Differenzierung in die stereoisomeren Formen direkt bestimmt werden. Die Fehlerbreite der Methode ist gering; es besteht eine gute Übereinstimmung mit der chemischen Methode von Rebelein.Bei den untersuchten Weinen variiert bei einem Gesamt-Milchsäuregehalt von 0,10–5,61 g/l der Gehalt an L-Lactat zwischen 0,00 und 4,82 g/l, der Gehalt an D-Lactat zwischen 0,05 und 0,84 g/l. Bei niedrigen Gesamt-Milchsäuregehalten von weniger als 0,6 g/1 kann sowohld-Lactat als auchl-Lactat überwiegen. Je höher die Gesamt-Milchsäuregehalte ansteigen, desto mehr überwiegt dasl-Lactat, dessen Anteil bei Gesamt-Milchsäuregehalten von über 2 g/1 mehr als 80 bzw. 90% des Gesamtlactats beträgt.
Herrn G. Maccagnan danken wir für die Durchführung zahlreicher Analysen. 相似文献
Enzymatic investigations on the contents ofl(+)- andd(–)-lactic acid in wines
Summary Contents ofl(+)- andd(–)-lactic acid in 99 wines have been determined enzymatically. Alkaline hydrolysis of the wines, as proposed in the literature, should not be carried out, because erronious results are hereby obtained, due to the formation of lactic acid from the residual sugars of the wines.Acidic hydrolysis or heating may be dropped because the amounts of esterified lactic acid in wines have been ascertained to be only 100–200 mg/l (max.). If just interested in total lactic acid, disregarding any differentiation of stereoisomeres, then total lactic acid can also be directly determined enzymatically. The method only has a slight marginal error and the results are in good agreement with the chemical method by Rebelein.The content of total lactic acid varies from 0,10–5,61 g/1; ofl-lactic acid from 0,00–4,82 g/l and ofd-lactic acid from 0,05–0,84 g/l. In wines with very low content of total lactic acid (< 0,6 g/l),d-lactic acid as well as L-lactic acid may be the dominent isomere. However, the higher the content of total lactic acid the more pronounced the content Ofl-lactic acid is. In wines containing more than 2 g/l of total lactic acid, more than 80-90% are taken up byl-lactic acid.
Herrn G. Maccagnan danken wir für die Durchführung zahlreicher Analysen. 相似文献