Effect of Bridge-Pier Differential Settlement on the Dynamic Response of a High-Speed Railway Train-Track-Bridge System

A model based on the theory of train-track-bridge coupling dynamics is built in the article to investigate how high-speed railway bridge pier differential settlement can affect various railway performance-related criteria. The performance of the model compares favorably with that of a 3D finite element model and train-track-bridge numerical model. The analysis of the study demonstrates that all the dynamic response for a span of 24 m is slightly larger than that for a span of 32 m. The wheel unloading rate increases with pier differential settlement for all of the calculation conditions considered, and its maximum value of 0.695 is well below the allowable limit. Meanwhile, the vertical acceleration increases with pier differential settlement and train speed, respectively, and the values for a pier differential settlement of 10 mm and speed of 350 km/h exceed the maximum allowable limit stipulated in the Chinese standards. On this basis, a speed limit for the exceeding pier differential settlement is determined for comfort consideration. Fasteners that had an initial tensile force due to pier differential settlement experience both compressive and tensile forces as the train passes through and are likely to have a lower service life than those which solely experience compressive forces

Enhanced Photodetection in Graphene-Integrated Photonic Crystal Cavity

We demonstrate the controlled enhancement of photoresponsivity in a graphene photodetector by coupling to slow light modes in a long photonic crystal linear defect cavity. Near the Brillouin zone (BZ) boundary, spectral coupling of multiple cavity modes results in broad-band photocurrent enhancement from 1530 nm to 1540 nm. Away from the BZ boundary, individual cavity resonances enhance the photocurrent eight-fold in narrow resonant peaks. Optimization of the photocurrent via critical coupling of the incident field with the graphene-cavity system is discussed. The enhanced photocurrent demonstrates the feasibility of a wavelength-scale graphene photodetector for efficient photodetection with high spectral selectivity and broadband response

The Optimal Patent Portfolio of The Technology Standards Alliances in Innovation Competition

Unlike the dominant theories based on the rigid assumption that “technology standards must contain only essential patents”, this paper discusses the standard alliances that are engaged in their cumulative innovation. Its focus is particularly on a more realistic setting that a standard alliance should contain both the essential and the non-essential patents. We use the essential-patent’s ratio, which denotes the percentage of the essential patents in the total patents in a standard, as the cumulative innovation model’s core variable. The mathematical analysis illustrates that the essential-patent’s ratio performs an important role in the arguments’ standards. There is an optimal portfolio that maximizes the alliances’ efficiency in an innovation competition. It implies that the social welfare effects depend on the dynamic trade-off between the long-term technical gap caused by the technological upgrades’ missing opportunities and the short-term welfare losses that consumers may suffer. The patents’ and antitrust laws should tolerate a certain number of non-essential patents being contained by the technology standards

Higher Carbohydrate Antigen 125 Levels Are Associated with Increased Risk of Coronary Heart Disease in Elderly Chinese: A Population-Based Case-Control Study

Background: High carbohydrate antigen 125 (CA-125) level was reported to be associated with some cardiac dysfunctions, such as chronic heart failure, but the relationship between CA-125 level and coronary heart disease (CHD) risk remains unclear. The aim of this study was to explore the potential association in a Chinese older population. Methods: In a population-based case-control study conducted in a Chinese older population, serum CA-125 levels were measured in 1177 diagnosed CHD patients and 3531 age and sex matched control subjects without CHD. Results: Serum CA-125 level was significantly higher in CHD patients than controls (P < 0.001) with adjustment for age, gender, smoking, drinking, BMI, physical activity, hypertension, dyslipidemia, diabetes mellitus, medication history and family history of CHD and myocardial infarction. CHD risk was doubled (OR: 2.10, 95%CI: 1.69-2.60) among subjects in the highest quartile compared to those in the lowest quartile of CA-125 level (Ptrend < 0.001). Furthermore, CA-125 levels were associated with CHD risks in subjects with age over 60 years (OR: 2.19, 95%CI: 1.75-2.73), current smokers (OR: 2.29, 95%CI: 1.50-3.49), current drinkers (OR: 2.35, 95%CI: 1.57-3.53) and subjects with hypertension (OR: 2.04, 95%CI: 1.71-2.43). Conclusions: Elevated serum CA-125 level might be associated with increased risk of coronary heart disease in the Chinese older population. Further investigations are needed to identify the possible biological role of CA-125 in CHD development in the future

Different Physical Activity Subtypes and Risk of Metabolic Syndrome in Middle-Aged and Older Chinese People

Background: The prevalence of metabolic syndrome (MetS) is growing rapidly in China. Tai chi and dancing are common types of exercise among middle-aged and elderly Chinese. It remains unclear whether these activities are associated with a lower risk of MetS. Methodology/Principal Findings A total of 15,514 individuals (6,952 men, 8,562 women) aged 50 to 70 years from the Dongfeng-Tongji Cohort in Shiyan, China participated in a cross-sectional study. Physical activity and other lifestyle factors were assessed with semi-structured questionnaires during face-to-face interviews. MetS was defined by the current National Cholesterol Education Program/Adult treatment Panel III criteria for Asian Americans. The prevalence of MetS was 33.2% in the study population. In the multivariable-adjusted logistic regression analyses, total physical activity levels were monotonically associated with a lower odds of MetS [OR 0.75 comparing extreme quintiles, 95% confidence interval (CI) 0.66–0.86, P<0.001]. Compared with non-exercisers in a specific exercise type, jogging (OR 0.82, 95% CI 0.68–1.00, P = 0.046), tai chi (OR 0.72, 95% CI 0.60–0.88, P<0.001), and dancing (OR 0.56, 95% CI 0.47–0.67, P<0.001) were associated with significantly lower odds of MetS. Furthermore, each 1–h/week increment in tai chi and dancing was associated with a 5% (95% CI 2%–9%) and a 9% (95% CI 6%, 12%) lower risk of MetS. Conclusions/Significance: Jogging, tai chi and dancing are associated with a significantly lower risk of having MetS in middle-aged and older Chinese. Future intervention studies should consider the role of jogging, tai chi and dancing in preventing MetS