1,657 research outputs found
Infective endocarditis complicated with progressive heart failure due to β-lactamase-producing Cardiobacterium hominis
No full textMolecular evidence for strain dissemination of Penicillium marneiffei: An emerging pathogen in Taiwan
No full textClinical features of patients with invasive Eikenella corrodens infections and microbiological characteristics of the causative isolates
No full text[[alternative]]The KT transition of YBCO films
No full text[[abstract]]我們想藉由觀察 YBaCuO 薄膜是否有 KT 變遷的現象,來瞭解薄膜厚度與
維度的關係。故我們製作二塊不同厚度 (240o,120o) 的薄膜,分別量測它
們的電阻率與 V-I 曲線, 並加以分析。其中240o 之 YBCO 薄膜由於厚度
較大,無法表現二維的行為。而120o 的薄膜其 V-I 曲線相關的次方定律
V=I,在 T<76.6K 時, n 滿足二維 Ginzberg- Landau 之線性關係式: n(
T)≒1+const(1-T/Tco)。以此直線與 n=1 之交點定出樣品的 T=79K。而
在n(T)約為5.1時, n 不再隨上述的線性關係式隨溫度下降,亦即發生了
KT 變遷中普遍躍遷的現象。我們分別以 n=3及 n=5.1 定出兩種不同的
Tkt, 來討論電阻率的結果。由電阻率的結果分析,無論那種決定 Tkt 的
方法在介於78.1及78.6K 間,其ln(R/Rn)與[(Tco-T)/(T-Tkt)]成線性關係
。亦就是出現 KT 理論中預測因二維渦流運動產生的特殊行為。所以其具
有二維的傳導現象。
In order to know the dimensionalities of YBCO films, we
measured the resistivities and I-V curves of two YBCO films(120
o,240o). According to our results,the film of 240o thickness
couldn't show the 2d behaviors.The power law of 120o film has
the universal jump phenomena and the resisti- vity behavior can
be explained by 2d free vortices mo- tion.We can say that the
YBCO film of 120o thickness is a 2d system.
In order to know the dimensionalities of YBCO films, we
Correction of scaling mismatches in oligonucleotide microarray data
No full textBackground: Gene expression microarray data is notoriously subject to high signal variability. Moreover, unavoidable variation in the concentration of transcripts applied to microarrays may result in poor scaling of the summarized data which can hamper analytical interpretations. This is especially relevant in a systems biology context, where systematic biases in the signals of particular genes can have severe effects on subsequent analyses. Conventionally it would be necessary to replace the mismatched arrays, but individual time points cannot be rerun and inserted because of experimental variability. It would therefore be necessary to repeat the whole time series experiment, which is both impractical and expensive. Results: We explain how scaling mismatches occur in data summarized by the popular MAS5 (GCOS; Affymetrix) algorithm, and propose a simple recursive algorithm to correct them. Its principle is to identify a set of constant genes and to use this set to rescale the microarray signals. We study the properties of the algorithm using artificially generated data and apply it to experimental data. We show that the set of constant genes it generates can be used to rescale data from other experiments, provided that the underlying system is similar to the original. We also demonstrate, using a simple example, that the method can successfully correct existing imbalancesin the data. Conclusion: The set of constant genes obtained for a given experiment can be applied to other experiments, provided the systems studied are sufficiently similar. This type of rescaling is especially relevant in systems biology applications using microarray data. © 2006 Barenco et al; licensee BioMed Central Ltd
Numerical analysis and discussion on the hot-spot stress concept applied to welded tubular KT joints
No full textNominal stresses have been used for a long time for the assessment of fatigue resistance of welded joints, however, this approach has strong limitations since the definition of the nominal stress may be subjective for complex welded details and/or complex loading. On the other hand, the hot-spot stress approach has been proposed to overcome these limitations considering the structural geometrical discontinuities. However, the hot-spot stress methods also present certain limitations, and the present study aims at evaluating the available numerical and analytical hot-spot stress methods proposed by DNVGL (2016) and IIW (2014). The particular case of an offshore tubular KT joint has been considered herein and discretized in two planes. It has been studied numerically using the ABAQUS software coupled with the hot-spot stress extrapolation methods described in IIW (2014) and DNVGL (2016). The influence of the weld geometry has been considered and evaluated. In addition to the numerical method, the present study has also considered the analytical approach proposed in DNVGL (2016) derived from the combination of Efthymiou solutions for the stress concentration factor with the method of superposition of stresses. The numerical models according to IIW (2014) have been found to be more conservative when compared with the mesh-size methods proposed by DNVGL (2016), both in numerical modelling without the weld or with weld. For the numerical models with weld cord, the mean values of normalized difference index obtained for all braces together, as a result of comparing numerical results with analytical solutions, are lower, when compared with results obtained from the numerical models without weld cord.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Steel & Composite Structure
Effect of Stress Ratio(R) and Stress Concentration Factor (Kt) on Fatigue Properties of WSTi6211 Titanium Alloy
No full textIn this paper, the author studied the effects of different stress ratios（R） and stress concentration factors(Kt) on the fatigue properties of WSTi6211 titanium alloy.Through S-N curve, the author obtained the fatigue ultimate strength of the material under different conditions and analyzed characteristics of fatigue fractures, including the crack source sourse, the crack growth region and the final rupture region. The results show that when Kt=1, R=0.5, the fatigue ultimate strength σD is 626MPa; when Kt = 1, R=0.06, the fatigue ultimate strength σD is 527.5MPa; when Kt=3, R=0.06, the ultimate fatigue strength σD is 267MPa. Fatigue performance is very sensitive to R and Kt. The larger R is, the larger the fatigue ultimate strength is. The larger Kt is, the smaller the fatigue limit strength is. The fracture morphology shows typical fatigue fracture morphology. Most of the cracks originate on the surface of specimens and have typical fatigue bands. With the decrease of stress, the area of crack growth zone increases
Effect of Stress Ratio(R) and Stress Concentration Factor (Kt) on Fatigue Properties of WSTi6211 Titanium Alloy
Full text linkIn this paper, the author studied the effects of different stress ratios（R） and stress concentration factors(Kt) on the fatigue properties of WSTi6211 titanium alloy.Through S-N curve, the author obtained the fatigue ultimate strength of the material under different conditions and analyzed characteristics of fatigue fractures, including the crack source sourse, the crack growth region and the final rupture region. The results show that when Kt=1, R=0.5, the fatigue ultimate strength σD is 626MPa; when Kt = 1, R=0.06, the fatigue ultimate strength σD is 527.5MPa; when Kt=3, R=0.06, the ultimate fatigue strength σD is 267MPa. Fatigue performance is very sensitive to R and Kt. The larger R is, the larger the fatigue ultimate strength is. The larger Kt is, the smaller the fatigue limit strength is. The fracture morphology shows typical fatigue fracture morphology. Most of the cracks originate on the surface of specimens and have typical fatigue bands. With the decrease of stress, the area of crack growth zone increases
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