171 research outputs found
A framework and implementation of information content reasoning in a database
No full text*The contributions of both authors are equal. Junkang Feng is the corresponding author. Abstract:- Databases ’ capability is limited in terms of inference. Especially, when users explore information beyond the scope of data within databases, the databases normally cannot provide the information. The underlying reason of the problem is that queries are answered based on a direct match between a query and data (up to aggregations of the data). We observe that it is possible to find information from a database beyond that. To this end, we propose a framework for information content reasoning in a database. A number of basic concepts are defined first. Then we present the framework and explain how it works. Moreover, we describe how such a framework is implemented by means of a prototype including a test with sample queries
Nouveaux concepts dans le dépôt de couches minces de silicium par PECVD : de la chimie du plasma aux applications de dispositifs photovoltaïques
No full textThis thesis describes the study of silicon thin film materials deposition and the resulting photovoltaic devices fabrication using different types of plasma-enhanced chemical vapour deposition (PECVD) techniques.In the first part, we combine a SiF4/H2 plasma chemistry with the matrix-distributed electron cyclotron resonance (MDECR) PECVD to obtain high growth rate microcrystalline silicon (µc-Si:H). Due to the special design of MDECR system, careful investigation of the impact energy of impinging ions to material deposition can be accessible. We find that moderate ion energy conditions is beneficial to achieve a significant drop in the density of nano-voids, thus a higher quality material with better stability can be obtained. A two-step deposition method is introduced as an alternative way to eliminate the existence of amorphous incubation layer during film growth.The second part of work is dedicate to the exploration of the Tailored Voltage Waveforms (TVWs) excitation technique for capacitively coupled plasmas (CCP) processes. As an advantage over the conventional sinusoidal excitations, TVWs technique provide an elegant solution for the ion flux-energy decoupling in CCP discharges through the electrical asymmetry effect, which makes the independent study of the impact of ion energy for material deposition at relatively high process pressure possible. Based on this insight, we have studied the deposition of µc-Si:H and amorphous silicon (a-Si:H) from the SiF4/H2/Ar and SiH4/H2 plasma chemistry, respectively. From the structural and electronic properties analysis, we find that the variation of ion energy can be directly translated into the material quality. We have further applied these results to photovoltaic applications and established bottom-up links from the controllable plasma parameters via TVWs to the deposited material properties, and eventually to the resulting device quality.In the last part, as a further application of TVWs, an “electrode-selective” effect has been discovered in the CCP processes. In the case of silicon thin film deposition from the SiF4/H2/Ar plasma chemistry, one can achieve a deposition process on one electrode, while at the same time either no deposition or an etching process on the counter electrode. This is due to two effects: the multi-precursor nature of the resulting surface process and the asymmetric plasma response through the utilization of TVWs. Moreover, such deposition/etching balance can be directly controlled through H2 flow rate. From a temporal asymmetry point of view, we have further studied the impact of process pressure and reactor geometry to the asymmetric plasma response for both the single-gas and multi-gas plasmas using the sawtooth waveforms. The product of pressure and inter-electrode distance P·di is deduced to be a crucial parameter in determine the plasma heating mode, so that a more flexible control over the discharge asymmetry as well as the relating “electrode-selective” surface process can be expected.Ce manuscrit présente l'étude de la fabrication de couches minces de silicium basée sur des différents types de dépôt chimique en phase vapeur assisté par plasma (PECVD) pour des applications dans le photovoltaïque. Tout d'abord, nous avons combiné une chimie du plasma halogéné en utilisant un mélange de SiF4/H2 et la technique plasmas distributés matriciellement à résonance cyclotronique électronique (MDECR) PECVD pour le dépôt de μc-Si:H à grande vitesse. Nous trouvons que les conditions d'énergie ionique modérée sont bénéfiques pour obtenir une diminution significative de la densité des nano-vides, et ainis nous pouvons obtenir un matériaux de meilleure qualité avec une meilleure stabilité. Une méthode de dépôt en deux étapes a été introduite comme moyen alternatif d'éliminer la formation d'une couche d'incubation amorphe pendant la croissance du film. Ensuite, nous avons exploré la technique d'excitation Tailored Voltage Waveform (TVW) pour les processus plasma radiofréquence capacitivement couplé (RF-CCP). Grâce à l'utilisation de TVW, il est possible d'étudier indépendamment l'influence de l'énergie ionique sur le dépôt de matériaux à une pression de processus relativement élevée. Basé sur ce point, nous avons étudié le dépôt de μc-Si:H et a-Si:H à partir des plasma de SiF4/H2/Ar et de SiH4/H2, respectivement. A partir d'une analyse des propriétés structurelles et électroniques, nous constatons que la variation de l'énergie ionique peut directement traduite dans la qualité du matériaux. Les résultats se sont appliqués aux dispositifs photovoltaïques et ont établi des liens complets entre les paramètres de plasma contrôlables par TVW et les propriétés de matériaux déposé, et finalement, les performances du dispositif photovoltaïque correspondant. Enfin, nous avons trouvé que dans le cas du dépôt de couches minces de silicium à partir du plasma de SiF4/H2/Ar à l'aide de sawtooth TVW, on peut réaliser un processus de dépôt sur une électrode, sans aucun dépôt ou gravure. contre-électrode. Ceci est dû à deux effets: la nature multi-précurseur du processus de surface résultant et la réponse de plasma spatiale asymétrique par l'effet d'asymétrie de pente de la sawtooth TVW. La découverte de tels procédés “electrode-selective” encourage la perspective que l'on puisse choisir un ensemble de conditions de traitement pour obtenir une grande variété de dépôts désirés sur une électrode, tout en laissant l'autre vierge
Impaired Sensitivity to Thyroid Hormone and Risk of Carotid Plaque Development in a Chinese Health Check-Up Population: A Large Sample Cross-Sectional Study
No full textJiangling Wang,1,2,* Lijuan Yang,3,* Wei Liu,1 Chaogang Wei,1 Junkang Shen1 1Department of Radiology, The Second Affiliated Hospital of Soochow University, Soochow, Jiangsu, People’s Republic of China; 2Department of Physical Diagnosis, Huadong Sanatorium, Wuxi, Jiangsu, People’s Republic of China; 3Department of Geriatric, Huadong Sanatorium, Wuxi, Jiangsu, People’s Republic of China*These authors contributed equally to this workCorrespondence: Junkang Shen; Chaogang Wei, Department of radiology, The Second Affiliated Hospital of Soochow University, No. 1055 Sanxiang Road, Soochow, 215004, People’s Republic of China, Email [email protected]; [email protected]: Previous research on the correlation between thyroid function and carotid plaque has revealed conflicting results, possibly attributable to the sensitivity of thyroid hormone indices. In this study, we aimed to analyze the association between thyroid hormone sensitivity indices and the risk of carotid plaque development in a Chinese health check-up population.Methods: A total of 19,388 health check-up subjects were included in this study (mean age: 50.78± 10.17 years). Central sensitivity to thyroid hormone was evaluated using the thyroid feedback quantile-based index (TFQI), the Chinese-referenced parametric TFQI (PTFQI), the TSH index (TSHI), and the thyrotropin thyroxine resistance index (TT4RI), while peripheral sensitivity to thyroid hormone was assessed by free triiodothyronine/free thyroxine (FT3/FT4) ratio. Multivariable logistic regression analyses were performed to detect the association between thyroid hormone sensitivity indices and carotid plaque risk, and subgroup analysis was also conducted to explore this association stratified by sex, age, obesity, and the status of smoking, drinking, diabetes, hypertension and dyslipidemia.Results: Among the 19,388 participants, 3753 (19.4%) had carotid plaque. In multivariable adjustment models, the risk of carotid plaque was positively associated with TSHI (odds ratio [OR]: 1.23; 95% confidence interval [CI]: 1.18~1.28), TT4RI (OR: 1.28; 95% CI: 1.23~1.33), TFQI (OR: 1.06; 95% CI: 1.02~1.10), and PTFQI (OR: 1.11; 95% CI: 1.07~1.16), respectively. Conversely, the risk of carotid plaque was negatively correlated with FT3/FT4 (OR: 0.94; 95% CI: 0.90~0.98). In stratified analyses, all thyroid hormone sensitivity indices significantly increased the risk of carotid plaque especially in females, subjects< 65 years, non-obese individuals, and those without current smoking, drinking, diabetes, hypertension and dyslipidemia.Conclusion: In Chinese health check-up populations, a considerable connection between reduced sensitivity to thyroid hormones and carotid plaque has been observed, especially in females, those younger than 65 years, non-obese individuals, and those without any current smoking, drinking, diabetes, hypertension, or dyslipidemia.Keywords: carotid plaque, thyroid hormone sensitivity, euthyroid, resistance to thyroid hormone, Chinese populatio
Periodic solutions for a Lienard equation with two deviating arguments
No full textIn this work, we prove the existence and uniqueness of periodic solutions for a Lienard equation with two deviating arguments. Our main tools are the Mawhin's continuation theorem and the Schwarz inequality. We obtain our results under weaker conditions than those in [14], as shown by an example in the last section of this article.Mathematic
Periodic solutions for a Lienard equation with two deviating arguments
No full textIn this work, we prove the existence and uniqueness of periodic solutions for a Lienard equation with two deviating arguments. Our main tools are the Mawhin's continuation theorem and the Schwarz inequality. We obtain our results under weaker conditions than those in [14], as shown by an example in the last section of this artticle
Study on the Properties and Fracture Splitting of Cast Steel Matrix Composites
No full textTo break through current limitations of fracture splitting materials for connecting rods, a bimetallic compound as a fracture splitting material was studied. The bimetallic sample was produced by investment casting, and interface performance tests and splitting tests were conducted. At a casting temperature of 1600 °C for 0.25 wt. % C cast carbon steel, the preheating temperature of T10A was 500 °C, and the thickness of T10A was in the range of 2–3 mm. The 0.25 wt. % C cast carbon steel and T10A were fully combined in the interface. The appearance of the fracture zone was a flat cleavage fracture, which would facilitate meshing of the cracked surface if the specimen were assembled and improve the quality of fracture splitting.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
A necessary and sufficient condition for existence and uniqueness of periodic solutions for a p-Laplacian Liénard equation
No full textIn this work, we investigate the following -Laplacian Liénard equation:
Under some assumption, a necessary and sufficient condition for the existence and uniqueness of periodic solutions of this equation is given by using Manásevich--Mawhin continuation theorem. Our results improve and extend some known results
Exotic topological phenomena in chiral superconducting states on doped quantum spin Hall insulators with honeycomb lattices
No full textWe conduct a theoretical investigation of the topological phenomena associated with chiral superconducting pairing states induced in a doped Kane-Mele model on a honeycomb lattice. Through numerical analysis, we obtain exotic phase diagrams for both the + and + superconducting states. In the case of the + pairing state, high Chern number states with =±4 emerge. The Chern number decreases as the spin-orbit coupling is introduced. For the + pairing state, additional phase transition lines are present in the overdoped region near the Van Hove singularity point, leading to the emergence of high Chern number phases with =±6. We further verify these high Chern number phases through the bulk-edge correspondence. To understand the origin of the exotic topological phase diagrams in the chiral superconducting state, we examine the electronic structure at the phase transition lines. This investigation provides insight into the complex interplay between chiral superconductivity and topological properties, potentially paving the way for the discovery of new materials with unique topological properties.</p
Public support for mobile community microgrids: Socioeconomic, perceptual and outage experience determinants of energy resilience
No full textReliability Analysis of Hydraulic System of a Tunnel-Erecting Machine Based on Dynamic Fault Tree and Bayesian Network
No full textPrefabricated utility tunnels play an important role in modern urban infrastructure construction. However, prefabricated utility tunnel segments are heavy, and the hoisting conditions are complicated, resulting in increased requirements in terms of the reliability of the equipment used for the erection and paving of utility tunnels, especially the hydraulic system of tunnel-erecting machines. Therefore, in this study, we performed reliability analysis of the hydraulic system of a tunnel-erecting machine. First, the working principle of the tunnel-erecting machine and its hydraulic system is analyzed, and a Takagi-Sugeno (T-S) dynamic fault tree model is constructed using the T-S dynamic fault tree analysis method, which is further transformed into a Bayesian network (BN) model. Secondly, according to the failure probability of the root node, combined with the BN conditional probability table (CPT), the failure probability of the leaf nodes of the hydraulic system of the tunnel-erecting machine in each time period and task time is forwardly inferred. Then, through the quantitative analysis of the sensitivity parameters in the BN analysis method, the importance of the components in the system can be reflected. Finally, the posterior probability of failure of the root node of the hydraulic system is calculated through the reverse reasoning of the BN analysis method, and the sensitive components of the system are identified. The results show that the proposed method can determine the main factors affecting the hydraulic system of a tunnel-erecting machine and provide reference for the safe operation of such equipment, as well as system maintenance
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