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2.
Wouter Bergmann Tiest Marcel Bruijn Henk Hoevers Piet de Korte Jan van der Kuur Wim Mels 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2004,520(1-3):329-332
We have performed numerical calculations of the noise in voltage-biased superconducting transition edge-based X-ray microcalorimeters, using a finite-element model. Details of the model are discussed, as well as results for different absorber geometries. The results are in agreement with an analytical model and show that the amount of internal thermal fluctuation noise can be reduced by using a segmented absorber. The simulation also agrees well with experimental data, which, for our detectors, contain no major unidentified noise sources. Furthermore, the discrepancy between the (small-signal) theoretical and the measured energy resolutions for 5.9 keV X-rays, for our sensors typically a factor of 2, is explained by a more accurate modelling of the sensor responsivity, taking into account the large signal behaviour. 相似文献
3.
Xiaoming Zhou Martin Jacobsson Henk Uijterwaal Piet Van Mieghem 《International Journal of Communication Systems》2008,21(6):643-663
Although packet delay and loss are two important parameters of the Internet performance, to the best of our knowledge, the evolution of large‐scale IPv6 delay and loss performance has previously not been studied. In this paper, we analyze more than 600 end‐to‐end IPv6 paths between about 26 testboxes of RIPE Network Coordination Centre over two years, and compare the delay and loss performance over time with their IPv4 counterparts. We present and discuss the measurement methodologies and show that IPv6 paths have a higher delay and loss than their IPv4 counterparts. The main reason for the worse performance stems from IPv6‐in‐IPv4 tunnels rather than from native IPv6 paths and such tunnels are still widely used today. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
4.
Anton A. Kiss Costin S. Bildea Alexandre C. Dimian Piet D. Iedema 《Chemical engineering science》2002,57(4):535-546
This article continues earlier work (Comput. Chem. Eng. 24 (2000) 209) concerning the design and control of isothermal reactor-separator-recycle systems. The multiplicity behaviour of six reaction systems of increasing complexity, from one-reactant, first-order reaction to chain-growth polymerisation, is investigated. Below a critical value of the plant Damkohler number, Da<Dacr, the only steady state involves infinite flow rates. Feasible steady states become possible if the critical value is exceeded, Da>Dacr. For one-reaction systems, one stable steady state is born at a transcritical bifurcation. For consecutive-reaction systems, including polymerisation, a fold bifurcation can lead to two feasible steady states. Moreover, the transcritical bifurcation is destroyed when two reactants are involved. If the gel-effect is included, a maximum of four steady states are possible. When multiple steady states exist, the achievable conversion is constrained by the instability of the low-conversion branch. This has practical importance for polymerisation systems when the radicals’ quasi-steady state assumption is not valid or the gel effect is significant. 相似文献
5.
The crosslink reaction is in fact from a commercial perspective the most reward ing reacting there is.It is used to adjust viscosity or rheology parameter in a large number of applications like p.e.the food or adhesives and textile printing. 相似文献
6.
Dina Had?iosmanovi? Damiano Bolzoni Pieter H. Hartel 《International Journal of Information Security》2012,11(4):231-251
SCADA (supervisory control and data acquisition) systems are used for controlling and monitoring industrial processes. We propose a methodology to systematically identify potential process-related threats in SCADA. Process-related threats take place when an attacker gains user access rights and performs actions, which look legitimate, but which are intended to disrupt the SCADA process. To detect such threats, we propose a semi-automated approach of log processing. We conduct experiments on a real-life water treatment facility. A preliminary case study suggests that our approach is effective in detecting anomalous events that might alter the regular process workflow. 相似文献
7.
Marco A. Jonker Piet S. van Roon Joop M. P. den Hartog 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,185(5):402-405
Summary The purpose of this study was to find experimental conditions for the complete solubility of collagen-free muscle proteins (CFMP) using acetone powder of Guelders ring sausage. Preliminary experiments were carried out to choose the best procedure for preparing the acetone dry powder. Two different methods of acetone extraction of minced sausage were compared. The acetone dry mass (ADM) method using continuous extraction in a Soxhlet [2] apparatus gave better results than the acetone powder (ACP) method, which used a blender [1]. The ADM method was used for further investigations. ADM was extracted with two types of sodium dodecyl sulphate (SDS), containing solvents A and B. Solvent A contains a Tris-boric acid buffer (pH 8.2) with 1.5% (m/v) SDS and 0.05% (m/v) dithioerythreitol [3]. Solvent B is a borate-chloric acid buffer (pH 9.0) with 2.0% (m/v) SDS and 1.0% (m/v) mercapto-ethanol [2]. Both solvents showed a linear relationship between the quantities of CFMP in ADM and the dissolved CFMP. The linear relationships were found between quantities of 10.0 and 30.0 mg (solution A) and of 5.0 and 30.0 mg ADM (solution B) per ml solvent. The solubility of CFMP was better in solvent B than in solution A. Completely dissolved CFMP from ADM was only obtained in the case of 5.0 mg ADM in 1.0 ml solution B. These conditions will be used in liquid chromatography experiments, the results of which will be reported later.
Supported by a grant from the Hoofdinspectie Levensmiddelen of the Ministry of Welzijn, Volksgezondheid en Cultuur 相似文献
Quantitative Aspekte zweier Verfahren für das Auflösen kollagenfreier Muskelproteine aus acetontrockenen Pulvern der Gelderschen Rauchwurst
Zusammenfassung Der Zweck dieser Untersuchungen ist, die experimentellen Bedingungen für die vollstän-dige Löslichkeit des kollagenfreien Muskelproteins (CFMP) aus dem Acetonpulver der Gelderschen Rauchwurst zu finden. Durch Vorversuche wurde die beste Arbeitsweise für das Zubereiten des Acetonpulvers gewählt. Zwei verschiedene Extraktionsverfahren mit zerkleinertem Wurstmaterial wurden miteinander verglichen. Die Methode mit der Acetontrockenmasse (ADM) mittels kontinuierlicher Extraktion [2] führte zu besseren Ergebnissen als die Methode mit Acetonpulver (ACP), wozu ein Mischgerät [1] verwendet wurde. Die ADM-Methode wurde für weitere Untersuchungen angewendet. ADM wurde mit zwei verschiedenen Extraktionslösungen von Natrium-Dodecylsulfat (SDS) (A und B) extrahiert. Lösung A enthalt einen Tris-Borsäure Puffer (pH 8,2) mit SDS (1,5%) und Dithioerithritol (0,05%) [3]. Die Lösung B enthält einen Borat-Salzsäure Puffer (pH 9,0) mit SDS (2,0%) und Mercapto-Ethanol (1,0%) [2]. Beide Extraktionslösungen zeigen ein lineares Verhalten zwischen den Mengen vom CFMP in ADM und in aufgelöstem CFMP. Diese Linearität wurde von 10,030,0 mg ADM (Lösungsmittel A) und von 5,030,0 mg ADM (Lösungsmittel B) gefunden. Die Lös-lichkeit in Lösung B ist gegeniiber Lösung A besser. Ein vollständig gelöstes CFMP aus ADM wurde nur bei der Extraktion von 5,0 mg ADM in 1,0 ml der Losung B erhalten. Diese Bedingung soll in unseren künftigen flüssigchromatographischen Experimenten verwendet werden.
Supported by a grant from the Hoofdinspectie Levensmiddelen of the Ministry of Welzijn, Volksgezondheid en Cultuur 相似文献
8.
Lejla Medzikovic Hylja Heese Pieter B. van Loenen Cindy P. A. A. van Roomen Ingeborg B. Hooijkaas Vincent M. Christoffels Esther E. Creemers Carlie J. M. de Vries Vivian de Waard 《International journal of molecular sciences》2021,22(4)
Fibrosis is a hallmark of adverse cardiac remodeling, which promotes heart failure, but it is also an essential repair mechanism to prevent cardiac rupture, signifying the importance of appropriate regulation of this process. In the remodeling heart, cardiac fibroblasts (CFs) differentiate into myofibroblasts (MyoFB), which are the key mediators of the fibrotic response. Additionally, cardiomyocytes are involved by providing pro-fibrotic cues. Nuclear receptor Nur77 is known to reduce cardiac hypertrophy and associated fibrosis; however, the exact function of Nur77 in the fibrotic response is yet unknown. Here, we show that Nur77-deficient mice exhibit severe myocardial wall thinning, rupture and reduced collagen fiber density after myocardial infarction and chronic isoproterenol (ISO) infusion. Upon Nur77 knockdown in cultured rat CFs, expression of MyoFB markers and extracellular matrix proteins is reduced after stimulation with ISO or transforming growth factor–β (TGF-β). Accordingly, Nur77-depleted CFs produce less collagen and exhibit diminished proliferation and wound closure capacity. Interestingly, Nur77 knockdown in neonatal rat cardiomyocytes results in increased paracrine induction of MyoFB differentiation, which was blocked by TGF-β receptor antagonism. Taken together, Nur77-mediated regulation involves CF-intrinsic promotion of CF-to-MyoFB transition and inhibition of cardiomyocyte-driven paracrine TGF-β-mediated MyoFB differentiation. As such, Nur77 provides distinct, cell-specific regulation of cardiac fibrosis. 相似文献
9.
Pieter Coenen Margriet Formanoy Marjolein Douwes Tim Bosch Heleen de Kraker 《Applied ergonomics》2014
Exposure to mechanical vibrations at work (e.g., due to handling powered tools) is a potential occupational risk as it may cause upper extremity complaints. However, reliable and valid assessment methods for vibration exposure at work are lacking. Measuring hand-arm vibration objectively is often difficult and expensive, while often used information provided by manufacturers lacks detail. Therefore, a subjective hand-arm vibration assessment method was tested on validity and inter-observer reliability. 相似文献
10.
综述了聚乙烯、聚丙烯单组分复合材料的发展概况及最新研究动态。介绍了熔融膜压法、粉末浸渍法、溶液浸渍法三类制备聚乙烯单组分复合材料的传统方法。重点介绍了热压法、共挤出热压法两类制备单组分复合材料的创新方法。分析了各制备方法的优缺点:熔融法、粉末法与溶液法效率均较低且复合材料中纤维含量较少,力学性能不佳;热压法由于初始材料为100%纤维,从而综合效率较高,力学性能良好,缺点为加工温度过于苛刻;共挤出热压法效率较高,在具有高的增强相含量的同时拥有较宽的加工温度范围,缺点为增强相强度需进一步提高。最后介绍了单组分复合材料的应用并对其研究与应用前景作了展望。 相似文献