526 research outputs found
Nonequilibrium Structure of Colloidal Dumbbells under Oscillatory Shear
We investigate the nonequilibrium behavior of dense, plastic-crystalline
suspensions of mildly anisotropic colloidal hard dumbbells under the action of
an oscillatory shear field by employing Brownian dynamics computer simulations.
In particular, we extend previous investigations, where we uncovered novel
nonequilibrium phase transitions, to other aspect ratios and to a larger
nonequilibrium parameter space, that is, a wider range of strains and shear
frequencies. We compare and discuss selected results in the context of novel
scattering and rheological experiments. Both simulations and experiments
demonstrate that the previously found transitions from the plastic crystal
phase with increasing shear strain also occur at other aspect ratios. We
explore the transition behavior in the strain-frequency phase and summarize it
in a nonequilibrium phase diagram. Additionally, the experimental rheology
results hint at a slowing down of the colloidal dynamics with higher aspect
ratio
Enhanced bias stress stability of a-InGaZnO thin film transistors by inserting an ultra-thin interfacial InGaZnO:N layer
Amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) having an ultra-thin nitrogenated a-IGZO (a-IGZO:N) layer sandwiched at the channel/gate dielectric interface are fabricated. It is found that the device shows enhanced bias stress stability with significantly reduced threshold voltage drift under positive gate bias stress. Based on x-ray photoelectron spectroscopy measurement, the concentration of oxygen vacancies within the a-IGZO:N layer is suppressed due to the formation of N-Ga bonds. Meanwhile, low frequency noise analysis indicates that the average trap density near the channel/dielectric interface continuously drops as the nitrogen content within the a-IGZO:N layer increases. The improved interface quality upon nitrogen doping agrees with the enhanced bias stress stability of the a-IGZO TFTs.This work was supported in part by the State Key
Program for Basic Research of China under Grant Nos.
2010CB327504, 2011CB922100, and 2011CB301900; in
part by the National Natural Science Foundation of China
under Grant Nos. 60936004 and 11104130; in part by the
Natural Science Foundation of Jiangsu Province under Grant
Nos. BK2011556 and BK2011050; and in part by the
Priority Academic Program Development of Jiangsu Higher
Education Institutions
Magnetoelectric plasma preparation of silicon-carbon nanocomposite as anode material for lithium ion batteries
A high-performance silicon-carbon nanocomposite facilely prepared by one-step magnetoelectric plasma pyrolysis of the mixture of methane, silane, and hydrogen is proposed for lithium-ion batteries. The ratio of silane, methane, and hydrogen was studied to optimize the properties of the composite. When the ratio of hydrogen/silane/methane is 1:1:3, the composite is composed of spherical Si nanoparticles that uniformly attach to the surface of the tremelliform carbon nanosheets framework, in which the tremelliform carbon nanosheets can effectively resist the volumetric change of the Si nanoparticles during the cycles and serve as electronic channels. The silicon-carbon nanocomposite exhibits a high reversible capacity (1007 mAh g−1 after 50 cycles), a low charge transfer resistance, and an excellent rate performance. In addition, the proposed process for synthesizing silicon-carbon nanocomposite without expensive materials or toxic reagents is an environmentally friendly and cost-effective method for mass production
Industrial structure and productivities in a two-sector growth model
We set up a model of heterogeneous-producers based on the semi-rival technology to study how industrial structure transforms and different sectional productivities. In a fully market-oriented economy, the industrial structure is endogenous and sectional productivities are the same. Employing fiscal subsidies to different industries lead to changes in both industrial structure and productivities, while the growth rate and interest rate keep fixed. For plausible values of parameters, the benchmark model generates results consistent with the United Statesâ data, and the extension model partly explains Chinaâs industrial transformation and changes of industrial productivities
Industrial structure and productivities in a two-sector growth model
We set up a model of heterogeneous-producers based on the semi-rival technology to study how industrial structure transforms and different sectional productivities. In a fully market-oriented economy, the industrial structure is endogenous and sectional productivities are the same. Employing fiscal subsidies to different industries lead to changes in both industrial structure and productivities, while the growth rate and interest rate keep fixed. For plausible values of parameters, the benchmark model generates results consistent with the United Statesâ data, and the extension model partly explains Chinaâs industrial transformation and changes of industrial productivities
Correlation between mobile phone addiction tendency and its related risk factor among Chinese college students: A cross-sectional study
Purpose: Mobile phone addiction prevalence is a global concern which has attracted great attention. It is now considered that excessive mobile phone usage is associated with potentially harmful and/or disturbing behaviors. The present study was aimed at exploring the current situation and related factors of mobile phone addiction tendency and providing a scientific suggestion for its prevention among college students.
Methods: A cross-sectional study was applied for stratified cluster random sampling among college students, including five survey tools: the basic information questionnaire, UCLA loneliness scale, college studentsâ interpersonal comprehensive diagnostic scale, the Pittsburgh sleep quality index scale and mobile phone addiction tendency scale (MPATS). SPSS v 17.0 statistical tool was applied to analyze data from the survey.
Results: A total of 760 questionnaires were administered of which 735 questionnaires were retrieved and the valid questionnaires were 730. Classification of mobile phone addiction tendency has statistical significance with grade. Also, classification of loneliness has statistical significance with major, grade and home address. Furthermore, classification of interpersonal relationship has statistical significance with romance status and grade. Additionally, classification of MPATS was positively correlated with classification of UCLA loneliness scale, Pittsburgh sleep quality index scale and interpersonal relationship scale. Interpersonal relationship, sleep quality, and loneliness were linearly correlated with mobile phone addiction tendency.
Conclusion: Grade, interpersonal relationship, sleep quality and loneliness were positively correlated with mobile phone addiction tendency, which are the associated risk factors. Therefore, concerns and interventions are required to decrease the risk factor for the sake of college studentsâ health
Prevalence and Risk Factors Associated with Prehypertension among Young and Middle-Aged Health Check-Up Population in Guangzhou
Objective: To provide basic information and theories for prehypertension early intervention, a systematic analysis of the epidemic status and risk factors among young and middle-aged was carried out here. Methods: This study relied on the data bank of a health check-up population of a class a tertiary general hospital in Guangdong province in 2015. Total 9540 young and middle-aged adults were enrolled, and 733 people were included to find out the effect with lifestyle in these crowd. Principal Components Analysis (PCA) of Factor (FA) was used to identify dietary patterns. The logistic regression model was used to find the risk factors of prehypertension. Results: Among 9540 young and middle-aged cases, the incidence of prehypertension was 36.6%. Moreover, the average age, proportion of male gender, overweight, FBG (fasting blood glucose), dyslipidemia, and hyperuricemia were significantly higher in the prehypertension group than in the optimal BP group. Multivariate logistic regression analysis indicated that age, total cholesterol, triglycerides, uric acid, body mass index and HR (heart rate) were risk factors, and female was a protective factor for prehypertension. Among 733 cases, the incidence of prehypertension was 35.1%. The proportion of smoking, drinking, physical workers, moderate and severe physical activity, and the intake of meat, dietary energy were significantly higher in the prehypertension group than in the optimal BP group. Dietary patterns included âmeat modelâ, âspice modelâ, âmain vegeTables modelâ and âhigh protein modelâ. Multivariate logistic regression analysis indicated that age, drinking were risk factors for prehypertension, while dietary milk intake, dietary magnesium intake were protective factors. Conclusions: Prehypertension is highly prevalent in Guangzhou. However, education about effective lifestyle modifications as an alcohol limit, increasing the intake of dairy products, and magnesium may intervene in the development of prehypertension. But how to develop targeted interventions for such groups need to be further explored. The present study would lay the theoretical foundation and basic data for the next step
Chemical-free Extraxtion of Cotton Stalk Bark Fibers by Steam Flash Explosion
Cotton stalk bark fibers (CSBF) were extracted by steam flash explosion, completed within 0.09 s, and the extracted fibers were compared with those obtained by conventional alkaline treatment. Results indicate that the optimum steam pressure was 2.5 MP a when steaming time was set to 2 min for extracting CSBF. Under the optimized conditions, the obtained CBSF had a cellulose content of 72%, length of 48 mm, fineness of 45 dtex, crystallinity index of 68, moisture regain of 8%, water rention of 98%, and tensile strength of 2.4 cN/dtex, which were similar to results obtained by conventional alkaline treatment. Compared with bark of cotton stalks, CSBF had lower moisture regain and water retention, and higher onset decomposition temperature. The results sow that moderate steam flash explosion is a chemical-free, quick, and effective method for exploring the industrial applications of bark of cotton stalks as natural cellulose fibers
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