2,898 research outputs found
[[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
Breast cancer data analysis for survivability studies and prediction
No full text© 2017 Elsevier B.V. Background Breast cancer is the most common cancer affecting females worldwide. Breast cancer survivability prediction is challenging and a complex research task. Existing approaches engage statistical methods or supervised machine learning to assess/predict the survival prospects of patients. Objective The main objectives of this paper is to develop a robust data analytical model which can assist in (i) a better understanding of breast cancer survivability in presence of missing data, (ii) providing better insights into factors associated with patient survivability, and (iii) establishing cohorts of patients that share similar properties. Methods Unsupervised data mining methods viz. the self-organising map (SOM) and density-based spatial clustering of applications with noise (DBSCAN) is used to create patient cohort clusters. These clusters, with associated patterns, were used to train multilayer perceptron (MLP) model for improved patient survivability analysis. A large dataset available from SEER program is used in this study to identify patterns associated with the survivability of breast cancer patients. Information gain was computed for the purpose of variable selection. All of these methods are data-driven and require little (if any) input from users or experts. Results SOM consolidated patients into cohorts of patients with similar properties. From this, DBSCAN identified and extracted nine cohorts (clusters). It is found that patients in each of the nine clusters have different survivability time. The separation of patients into clusters improved the overall survival prediction accuracy based on MLP and revealed intricate conditions that affect the accuracy of a prediction. Conclusions A new, entirely data driven approach based on unsupervised learning methods improves understanding and helps identify patterns associated with the survivability of patient. The results of the analysis can be used to segment the historical patient data into clusters or subsets, which share common variable values and survivability. The survivability prediction accuracy of a MLP is improved by using identified patient cohorts as opposed to using raw historical data. Analysis of variable values in each cohort provide better insights into survivability of a particular subgroup of breast cancer patients
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
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
HOXC6 overexpression as a poor prognostic factor in patients with nasopharyngeal carcinoma
No full text[[abstract]]Background: Though the advances in diagnostic imaging and treatment modalities have achieved better locoregional control of nasopharyngeal carcinoma (NPC), it appears less satisfactory in fi nal treatment outcomes. Through data mining from public domain, homeobox C6 (HOXC6) was fi rst identifi ed as a differentially upregulated gene associated with regulation of transcription from RNA polymerase II promoter in the transcriptome of NPCs. HOXC6 belongs to a member of the homeobox family, deregulated expression of which has been observed in many tumor types including leukemia, breast, lung, and prostate cancer. Since its signifi cant has not been systematically investigated in NPC, we therefore explored the signifi cance of HOXC6 immunoexpression status and its association with cell proliferation index Ki-67 in a large cohort of NPC patients.Design: HOXC6 and Ki-67 immunohistochemistry was retrospectively performed and analyzed using H-score method for biopsy specimens from 124 NPC patients who received standard treatment without distant metastasis at initial diagnosis. Those cases with H-score larger than the median value were defi ned as HOXC6 overexpression. The results were correlated with the clinicopathological variables, disease-specifi c survival (DSS) and metastasis-free survival (MeFS).Results: HOXC6 overexpression was signifi cantly positively associated with Ki-67 expression, and signifi cantly associated with increments of tumor stage (p=0.024), advanced nodal status (p<0.001) and American Joint Committee on Cancer (AJCC) stage (p=0.002). Its overexpression also correlated with worse prognosis in terms of DSS (p=0.0008), MeFS (p=0.0047) univariately. In multivariate comparisons, HOXC6 overexpression still remained prognostically independent to portend worse DSS (p=0.015, hazard ratio=1.988) and MeFS (p=0.036, hazard ratio=1.899), together with advanced AJCC stages III-IV (p=0.024, DSS; p=0.043, MeFS).Conclusions: HOXC6 expression is upregulated in a subset of NPCs and its increased immunoexpression signifi cantly correlated with advanced stages and tumor aggressiveness, justifying the potentiality of HOXC6 as a prognostic biomarker and a novel therapeutic target of NPC
Preface: Towards the Next Generation of Information Systems: Enhancing Traceability and Transparency
No full textThe information systems community plays a significant role in providing theories for guiding the creation of more effective information systems. This is nowadays most prominent in supporting the ongoing evolution of Artificial Intelligence (AI) and decision-making systems. As these systems are becoming increasingly reliable, and supplanting the presence of humans, the question of accountability and trust in these systems is increasingly coming to the fore. This editorial positions and showcases a collection of papers from the 2018 Australasian Conference on Information Systems within this context.
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BARYON MAGNETIC-MOMENTS WITH CONFINED QUARKS
No full textAstronomy & AstrophysicsPhysics, Particles & FieldsSCI(E)0ARTICLE3920-9234
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