One-step hydrothermal synthesis of fluorescence carbon quantum dots with high product yield and quantum yield

A one-step hydrothermal synthesis of nitrogen and silicon co-doped fluorescence carbon quantum dots (N,Si-CQDs), from citric acid monohydrate and silane coupling agent KH-792 with a high product yield (PY) of 52.56% and high quantum yield (QY) of 97.32%, was developed. This greatly improves both the PY and QY of CQDs and provides a new approach for a large-scale production of high-quality CQDs. Furthermore, N,Si-CQDs were employed as phosphors without dispersants to fabricate white light-emitting diodes (WLEDs) with the color coordinates at (0.29, 0.32). It is suggested that N,Si-CQDs have great potential as promising fluorescent materials to be applied in WLEDs.Peer reviewe

Associations Between General and Central Obesity and Hypertension Among Children: The Childhood Obesity Study in China Mega-Cities

In this study, we examined the associations of general and central obesity and hypertension among Chinese children. Data was collected from 1626 children aged 7-16 years and their parents in four mega-cities across China. Mixed effect models examined associations of general and central obesity with hypertension, and between body mass index (BMI), waist circumference (WC), waist-To-height ratio (WHtR), systolic blood pressure (SBP) and diastolic blood pressure (DBP). The prevalence of general obesity, central obesity, and hypertension among the children was 11.1%, 19.7%, and 9.0%, respectively. More boys had general and central obesity than girls (15.2% vs. 6.9%; 27.4% vs. 11.7%, respectively; both P \u3c 0.0001). Sex difference in hypertension rate was not statistically significant (9.3% in boys vs. 8.8% in girls, P = 0.7341). Both SBP and DBP were positively associated with BMI, WC, and WHtR, regardless of sex and region. General obesity (OR = 5.94, 95% confidence interval [CI]: 3.69-9.55) and central obesity (OR = 3.45, 95% CI: 2.27-5.23) were strongly associated with hypertension. The prevalence of general obesity, central obesity, and hypertension was high among Chinese children in the four mega-cities across China. Children\u27s BMI, WC, and WHtR were positively associated with their SBP and DBP. Obese children were 3-6 times more likely to have hypertension

A Design Study of Dual-Stator Permanent Magnet Brushless DC Motor

Dual-stator permanent magnet brushless DC Motor (DSBLDC) features high efficiency and torque-density. As DSBLDC could operate in various states according to different winding connection modes, it is fully qualified for electric vehicle (EV) drive. Unfortunately, due to the particular dual-stator structure, this kind of motor is difficult to be designed by available design methods. However, this paper demonstrates that a DSBLDC with series magnetic circuit structure can be regarded as being consisted of two independent BLDCs, an inner-rotor BLDC and an outer-rotor BLDC. Thus, the DSBLDC can be divided into two single-stator BLDCs. Based on this demonstration, the design method is verified by finite element analysis (FEA), and the basic design steps are given. Furthermore, experimental results of the prototype motor have verified the correction of the method, which also indicates that the motor with superior performance is adapted to EV drive

nn-body Correlation of Tonks-Girardeau Gas

For the well-known exponential complexity it is a giant challenge to calculate the correlation function for general many-body wave function. We investigate the ground state $n$th-order correlation functions of the Tonks-Girardeau (TG) gases. Basing on the wavefunction of free fermions and Bose-Fermi mapping method we obtain the exact ground state wavefunction of TG gases. Utilizing the properties of Vandermonde determinant and Toeplitz matrix, the $n$th-order correlation function is formulated as $(N-n)$-order Toeplitz determinant, whose element is the integral dependent on 2$(N-n)$ sign functions and can be computed analytically. By reducing the integral on domain $[0,2\pi]$ into the summation of the integral on several independent domains, we obtain the explicit form of the Toeplitz matrix element ultimately. As the applications we deduce the concise formula of the reduced two-body density matrix and discuss its properties. The corresponding natural orbitals and their occupation distribution are plotted. Furthermore, we give a concise formula of the reduced three-body density matrix and discuss its properties. It is shown that in the successive second measurements, atoms appear in the regions where atoms populate with the maximum probability in the first measurement.Comment: 8 pages, 7 figure

Numerical Study of Cold Dome Variability induced by Typhoon Morakot (2009) off Northeastern Taiwan

The ocean response to the passage of Typhoon Morakot (2009) near the continental shelf of the East China Sea off northeastern Taiwan was evaluated using a numerical ocean model to clarify how the permanent upwelling feature in this region was changed during this storm event. Several studies have identified the presence of the Kuroshio subsurface water in this Cold Dome region, which results from the interactions among the monsoon, the Kuroshio and the shelf topography. This study shows how tropical cyclone Morakot\u27s passage quickly disturbed the circulation around Taiwan and induced a short-period intrusion of the Kuroshio water onto the continental shelf. The intrusion began during the second half of the forced period and lasted for approximately two days. The upwelling and northward flow were greatly enhanced during this period, allowing the subsurface water from the upstream Kuroshio to be transported onto the shelf and to reach the Cold Dome. The intrusion-induced cold anomaly along the north coast of Taiwan was much more significant than what can be achieved by local vertical mixing. The cold anomaly later formed an eddy, which gradually propagated with the Kuroshio to the northeast

Market Discipline and City Commercial Banks’ Risk Taking

Since the end of 2006, commitment period of China’s joining into the WTO is over, Chinese bank industry fully opened, and market competition has become stronger. But China has an implicit deposit insurance, under this circumstances whether market discipline exists in city commercial banks has become an important question. This paper used data from 60 city commercial banks between 2003 and 2010 to analyze this issue. Study shows that before Chinese bank sector fully opened, the power of market is weak, market is unable to restrict city commercial bank’s risk effectively; in the wake of Chinese bank sector opening at the end of 2006, the power of market discipline gradually appeared, which controlled risk taking efficiently by price mechanism, but quantity discipline is always not obvious.Key words: Market discipline; Banking sector; Risk takin

Examining information sharing in Enterprise 2.0: Applying theory of attachment

With its immense potential for enriching communication, promoting information sharing, enabling collaboration and improving job performance, Enterprise 2.0 becomes one of the most promising technological innovations in the business domain. Although，more and more firms are implementing Enterprise 2.0 to promote knowledge sharing and collaboration among employees in recent years. There is only a few empirical research has been performed to identify individuals’ information sharing through Enterprise 2.0. The high practical relevance and lack of research indicate the importance of this study. This study aims to apply the Attachment Theory to propose a research model that incorporates eight variables to predict individuals’ willingness of information sharing through Enterprise 2.0 applications. To test the model, structural equation modelling is employed to analyse data collected from respondents who have experience of using Enterprise 2.0 in a top-raking Chinese Internet survey platform. The findings of this research provide application designer and firm managers with effective methods to promote individuals’ willingness of information sharing through Enterprise 2.0.This research also provides a theoretical foundation for academics and practical implications for the development of Enterprise 2.0