Thermal Shock Fracture Behaviors of Functionally Graded Ceramics

This thesis uses a thermal fracture mechanics model to study the thermal shock fracture behavior of functionally graded ceramics (FGC). The specimen used in this study is a FGC strip with an edge crack on one surface. A severe thermal shock is applied on the cracked surface. The temperature field in a thermally shocked FGC strip is evaluated first using a closed form solution. Thermal stresses, thermal stress intensity factors (TSIF) and critical thermal shocks are evaluated using a thermomechanics and fracture mechanics approach. The effective thermal properties of the FGC specimens are estimated using micromechanics models for conventional composites. Some numerical results of critical thermal shocks are provided for FGC specimens with constant elastic material properties and graded thermal properties in the thickness direction of the strips. Also, examples of thermal stresses and thermal stress intensity factors (TSIFs) are provided. The results show that the components gradation of the FGC composites has significant influence on the specimens\u27 thermal shock behavior. When the volume fraction of the FGC strip is changed rapidly, the critical thermal shock is changed dramatically

Oxygen dissociation on the C3N monolayer: A first-principles study

The oxygen dissociation and the oxidized structure on the pristine C3N monolayer in exposure to air are the inevitably critical issues for the C3N engineering and surface functionalization yet have not been revealed in detail. Using the first-principles calculations, we have systematically investigated the possible O2 adsorption sites, various O2 dissociation pathways and the oxidized structures. It is demonstrated that the pristine C3N monolayer shows more O2 physisorption sites and exhibits stronger O2 adsorption than the pristine graphene. Among various dissociation pathways, the most preferable one is a two-step process involving an intermediate state with the chemisorbed O2 and the barrier is lower than that on the pristine graphene, indicating that the pristine C3N monolayer is more susceptible to oxidation than the pristine graphene. Furthermore, we found that the most stable oxidized structure is not produced by the most preferable dissociation pathway but generated from a direct dissociation process. These results can be generalized into a wide range of temperatures and pressures using ab initio atomistic thermodynamics. Our findings deepen the understanding of the chemical stability of 2D crystalline carbon nitrides under ambient conditions, and could provide insights into the tailoring of the surface chemical structures via doping and oxidation.Comment: 23 pages,8 figure

ERNIE-mmLayout: Multi-grained MultiModal Transformer for Document Understanding

Recent efforts of multimodal Transformers have improved Visually Rich Document Understanding (VrDU) tasks via incorporating visual and textual information. However, existing approaches mainly focus on fine-grained elements such as words and document image patches, making it hard for them to learn from coarse-grained elements, including natural lexical units like phrases and salient visual regions like prominent image regions. In this paper, we attach more importance to coarse-grained elements containing high-density information and consistent semantics, which are valuable for document understanding. At first, a document graph is proposed to model complex relationships among multi-grained multimodal elements, in which salient visual regions are detected by a cluster-based method. Then, a multi-grained multimodal Transformer called mmLayout is proposed to incorporate coarse-grained information into existing pre-trained fine-grained multimodal Transformers based on the graph. In mmLayout, coarse-grained information is aggregated from fine-grained, and then, after further processing, is fused back into fine-grained for final prediction. Furthermore, common sense enhancement is introduced to exploit the semantic information of natural lexical units. Experimental results on four tasks, including information extraction and document question answering, show that our method can improve the performance of multimodal Transformers based on fine-grained elements and achieve better performance with fewer parameters. Qualitative analyses show that our method can capture consistent semantics in coarse-grained elements.Comment: Accepted by ACM Multimedia 202

Serum Neuroactive Metabolites of the Tryptophan Pathway in Patients With Acute Phase of Affective Disorders

BACKGROUND: Many studies showed disrupted tryptophan metabolism in patients with affective disorders. The aims of this study were to explore the differences in the metabolites of tryptophan pathway (TP) and the relationships between TP metabolites and clinical symptoms, therapeutic effect in patients with bipolar disorder with acute manic episode (BD-M), depressive episode (BD-D) and major depressive disorder (MDD). METHODS: Patients with BD-M (n=52) and BD-D (n=39), MDD (n=48) and healthy controls (HCs, n=49) were enrolled. The serum neuroactive metabolites levels of the TP were measured by liquid chromatography-tandem mass spectrometry. Hamilton Depression Scale-17 item (HAMD-17) and Young Mania Rating Scale (YMRS) were used to evaluate depressive and manic symptoms at baseline and after 8 weeks of antidepressants, mood stabilizers, some also received antipsychotic medication. RESULTS: The levels of tryptophan (TRP) and kynurenic acid (KYNA) were significantly lower and the ratios of tryptophan/kynurenine (TRP/KYN), 5-hydroxytryptamine/tryptophan (5-HT/TRP), quinolinic acid/kynurenic acid (QUIN/KYNA) were higher in BD-M, BD-D, MDD vs. HC. The levels of QUIN and the ratios of QUIN/KYNA were higher in BD-M than in BD-D, MDD, and HCs. The 5-hydroxyindoleacetic acid (5-HIAA) levels of patients with MDD were significantly higher than those in BD-M and BD-D. Binary logistic regression analysis showed the lower peripheral KYNA, the higher the QUIN level, and the higher the risk of BD-M; the lower peripheral KYNA and the higher KYN/TRP and 5-HT/TRP, the higher the risk of BD-D; and the lower the peripheral KYNA level and the higher the KYN/TRP and 5-HT/TRP, the higher the risk of MDD. Correlation analysis, showing a significant association between tryptophan metabolites and improvement of clinical symptoms, especially depression symptoms. CONCLUSIONS: Patients with affective disorders had abnormal tryptophan metabolism, which involved in 5-HT and kynurenine pathway (KP) sub-pathway. Tryptophan metabolites might be potential biomarkers for affective disorders and some metabolites have been associated with remission of depressive symptoms

Global Infectious Diseases in September 2022: Monthly Analysis

The threat of infectious diseases caused by pathogenic microorganisms to both human health and the economy is enormous. Coronavirus Disease 2019 (COVID-19) remains a global pandemic. In contrast to many other infectious diseases, monkeypox spreads rapidly and cannot be ignored. Collection of data on contagious diseases can provide quantitative evidence to support effective pandemic control strategies. Global data on predominant infectious diseases collected in the past several weeks and a summary of their epidemiology are presented herein

Global Infectious Diseases in October 2022: Monthly Analysis

Infectious diseases continue to pose a major threat to worldwide public health. Infections by Coronavirus Disease 2019 have eased but continue to negatively affect international economic development. The situation of other infectious diseases, such as monkeypox and mosquito-borne diseases, became stable in October. Monitoring epidemic situation of infectious diseases can provide rapid insight into global transmission trends and assist in predicting epidemic situations. Visualizations and analyses summarizing the past few weeks of global data on major infectious diseases are provided

Global Infectious Diseases in December 2022: Monthly Analysis

The emergence and reoccurrence of infectious diseases constitute a significant threat to human health. Data for this paper were mainly obtained from official websites, such as the WHO and national CDC websites. The report summarizes and analyzes information on infectious diseases for early outbreak monitoring from 24 November to 23 December 2022. Monkeypox cases declined in December 2022 with few deaths, while cholera infections have increased in African regions and war-torn countries. Most sub-Saharan countries are affected by insect-borne diseases, such as dengue, Lassa, and chikungunya fever

Global Infectious Diseases in February 2023: Monthly Analysis

Public health security in human societies is placed under enormous strain by infectious disease epidemics. According to the WHO, COVID-19 and Mpox remain on the list of PHEICs, whereas cholera, dengue, and other contagious diseases remain endemic in several countries and regions. Data on prevalent infectious diseases have been collected worldwide in recent weeks, and may provide new ideas for international collaboration in public health

Global Infectious Diseases in August 2023: A Monthly Analysis

Infectious diseases frequently affect children and adults worldwide. Owing to their specific biology and mode of transmission, the presence of infected individuals or carriers in a region often leads to outbreaks of the disease in that region, and in severe cases, to the death of the infected individual. Infectious diseases have been one of the main causes of mass disability or death in humans for centuries. Surveillance of infectious diseases on a continental scale is therefore important for assessing, recognizing, and preventing the risks that these diseases may pose to animal and human health on a global scale. This report focuses on global infectious disease outbreaks and systematically summarises the timing and location of outbreaks in infected populations between 24 July and 23 August 2023 based on the Global Outbreak Information Surveillance System (GOSIS) of Shusi Technologies

Global Infectious Diseases in June 2023: Monthly Analysis

Infectious diseases are a class of diseases caused by various pathogens that can be transmitted between humans and animals or between humans and animals, thus seriously affecting the development of human society. To control the spread of infectious diseases worldwide and ensure the safety of people’s lives, it is essential to regularly analyze global infectious disease cases. This review is based on data from the World Health Organization, the Centers for Disease Control in countries around the world, Outbreak News Today and many other epidemiological websites to predict the global infectious disease outbreak trend. In addition, using the Shuci Technology global epidemic information monitoring system, we analyzed the distribution of infectious diseases that occurred around the world from 24 May 2023 to 23 June 2023