86 research outputs found

    Scalability of Atomic-Thin-Body (ATB) Transistors Based on Graphene Nanoribbons

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    A general solution for the electrostatic potential in an atomic-thin-body (ATB) field-effect transistor geometry is presented. The effective electrostatic scaling length, {\lambda}eff, is extracted from the analytical model, which cannot be approximated by the lowest order eigenmode as traditionally done in SOI-MOSFETs. An empirical equation for the scaling length that depends on the geometry parameters is proposed. It is shown that even for a thick SiO2 back oxide {\lambda}eff can be improved efficiently by thinner top oxide thickness, and to some extent, with high-k dielectrics. The model is then applied to self-consistent simulation of graphene nanoribbon (GNR) Schottky-barrier field-effect transistors (SB-FETs) at the ballistic limit. In the case of GNR SB-FETs, for large {\lambda}eff, the scaling is limited by the conventional electrostatic short channel effects (SCEs). On the other hand, for small {\lambda}eff, the scaling is limited by direct source-to-drain tunneling. A subthreshold swing below 100mV/dec is still possible with a sub-10nm gate length in GNR SB-FETs.Comment: 4 figures, accepted by ED

    Developing a biogas centralised circular bioeconomy using agricultural residues - Challenges and opportunities

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    Anaerobic digestion (AD) can be used as a stand-alone process or integrated as part of a larger biorefining process to produce biofuels, biochemicals and fertiliser, and has the potential to play a central role in the emerging circular bioeconomy (CBE). Agricultural residues, such as animal slurry, straw, and grass silage, represent an important resource and have a huge potential to boost biogas and methane yields. Under the CBE concept, there is a need to assess the long-term impact and investigate the potential accumulation of specific unwanted substances. Thus, a comprehensive literature review to summarise the benefits and environmental impacts of using agricultural residues for AD is needed. This review analyses the benefits and potential adverse effects related to developing biogas-centred CBE. The identified potential risks/challenges for developing biogas CBE include GHG emission, nutrient management, pollutants, etc. In general, the environmental risks are highly dependent on the input feedstocks and resulting digestate. Integrated treatment processes should be developed as these could both minimise risks and improve the economic perspective.acceptedVersio

    Understanding the Factors That Control theFormation and Morphology of Zn5(OH)8(NO3)2⋅2H2Othrough Hydrothermal Route

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    The influence of the choice of ethanol-water volume ratio, concentration of zinc salt, and ZnO buffer layer on the formation andmorphology of Zn5(OH)8(NO3)2⋅2H2O grown from the hydrothermal route was systematically discussed. Experimental resultssuggested that Zn5(OH)8(NO3)2⋅2H2O rectangle sheets and Zn5(OH)8(NO3)2⋅2H2O upright-standing plates were obtained bylimiting ethanol-water volume ratio. The concentration of zinc salt was crucial for getting phase-pure Zn5(OH)8(NO3)2⋅2H2O. Thepresence of ZnO buffer layer could lead to the that chemical composition of product grown on the substrate was totally differentfrom the product grown in the solution. Possible formation mechanism of Zn5(OH)8(NO3)2⋅2H2O was also studied. Ramanspectrum of Zn5(OH)8(NO3)2⋅2H2O displays a complex behavior with four modes, which can be assigned to the vibrationalmodes of Zn–H–O, Zn–O, H2O-nitrate, and nitrate. Porously ZnO rectangle sheets were obtained by thermal treatment ofZn5(OH)8(NO3)2⋅2H2O rectangle sheets

    The Mediating Effects of Stigma on Depressive Symptoms in Patients With Tuberculosis: A Structural Equation Modeling Approach

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    Objectives: To date, the complex interrelationships between family function, doctor-patient communication, knowledge about tuberculosis (TB), stigma, and depressive symptoms among patients with TB are insufficiently understood. We explored the interrelationships between family function, doctor-patient communication, knowledge about TB, TB-related stigma, and depressive symptoms and examined whether TB-related stigma played a mediating role.Methods: A cross-sectional survey was conducted between October 1, 2013 and March 31, 2014 in Hubei province, central China. Data were collected from 1,309 patients with TB using a structured questionnaire that measured family function, doctor-patient communication, knowledge about TB, stigma, and depressive symptoms. Structural equation modeling was used to examine the interrelationships among the study variables based on the hypothesized model.Results: The proposed model provided a good fit to the obtained data. There were indirect effects between family function, doctor-patient communication, knowledge about TB, and depressive symptoms through stigma (β = −0.048, P = 0.002; β = −0.028, P = 0.001; β = −0.021, P = 0.009, respectively). Stigma partially mediated the effect of family function and knowledge about TB on depressive symptoms and fully mediated the effect of doctor-patient communication on depressive symptoms.Conclusions: This study elucidated the pathways linking family function, doctor-patient communication, and knowledge about TB to depressive symptoms and confirmed that the effect of those variables on depressive symptoms can be mediated by stigma. Those findings provide direction and information for depression interventions among patients with TB

    Wall enhancement predictive of abnormal hemodynamics and ischemia in vertebrobasilar non-saccular aneurysms: a pilot study

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    ObjectiveTo analyze how wall enhancement affects hemodynamics and cerebral ischemic risk factors in vertebrobasilar non-saccular intracranial aneurysms (VBNIAs).Materials and methodsTen consecutive non-saccular aneurysms were collected, including three transitional vertebrobasilar dolichoectasia (TVBD). A wall enhancement model was quantitatively constructed to analyze how wall enhancement interacts with hemodynamics and cerebral ischemic factors.ResultsEnhanced area revealed low wall shear stress (WSS) and wall shear stress gradient (WSSG), with high oscillatory shear index (OSI), relative residence time (RRT), and gradient oscillatory number (GON) while the vortex and slow flow region in fusiform aneurysms are similar to TVBD fusiform aneurysms. With low OSI, high RRT and similar GON in the dilated segment, the enhanced area still manifests low WSS and WSSG in the slow flow area with no vortex. In fusiform aneurysms, wall enhancement was negatively correlated with WSS (except for case 71, all p values  < 0.05, r = −0.52 ~ −0.95), while wall enhancement was positively correlated with OSI (except for case 5, all p values < 0.05, r = 0.50 ~ 0.83). For the 10 fusiform aneurysms, wall enhancement is significantly positively correlated with OSI (p = 0.0002, r = 0.75) and slightly negatively correlated with WSS (p = 0.196, r = −0.30) throughout the dataset. Aneurysm length, width, low wall shear stress area (LSA), high OSI, low flow volume (LFV), RRT, and high aneurysm-to-pituitary stalk contrast ratio (CRstalk) area plus proportion may be predictive of cerebral ischemia.ConclusionA wall enhancement quantitative model was established for vertebrobasilar non-saccular aneurysms. Low WSS was negatively correlated with wall enhancement, while high OSI was positively correlated with wall enhancement. Fusiform aneurysm hemodynamics in TVBD are similar to simple fusiform aneurysms. Cerebral ischemia risk appears to be correlated with large size, high OSI, LSA, and RRT, LFV, and wall enhancement

    Nemo-like kinase associated with proliferation and apoptosis by c-Myb degradation in breast cancer.

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    Nemo-like kinase (NLK), a mediator of the Wnt signaling pathway, binds directly to c-Myb, leading to its phosphorylation, ubiquitination and proteasome-dependent degradation. NLK was significantly downregulated in the breast cancer tissues compared to corresponding normal tissues. NLK expression was negatively correlated with c-Myb expression. NLK suppressed proliferation, induced apoptosis and mediated c-Myb degradation in MCF-7 cells via a mechanism that seems to involve c-myc and Bcl2. These findings might provide a novel target for therapeutic intervention in patients with breast cancer

    structureanddiffusivityofoxygeninconcentratedalkalimetalhydroxidesolutionsamoleculardynamicssimulationstudy

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    采用分子动力学方法对不同温度(25-120°C)及碱浓度(1:100-1:5,摩尔比)下Na OH和KOH溶液中的氧气进行了模拟.本文考察了Na OH及KOH溶液中溶剂-溶剂、氧气-溶剂及氧气-溶质的径向分布函数,并采用爱因斯坦方程从均方位移曲线中计算得到了氧气及溶质离子的扩散系数.结果显示随着碱浓度的升高,氧气扩散系数逐渐减少;在相同条件下,氧气在Na OH溶液中扩散系数小于在KOH溶液中的扩散系数;溶质离子扩散系数的变化规律与氧气一致.通过与现有实验结果对比,发现了分子动力学方法的可靠性及用于研究实验受限领域的优越性

    氧气在碱溶液中结构与扩散系数的分子动力学模拟

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    采用分子动力学方法对不同温度(25-120°C)及碱浓度(1:100-1:5,摩尔比)下Na OH和KOH溶液中的氧气进行了模拟.本文考察了Na OH及KOH溶液中溶剂-溶剂、氧气-溶剂及氧气-溶质的径向分布函数,并采用爱因斯坦方程从均方位移曲线中计算得到了氧气及溶质离子的扩散系数.结果显示随着碱浓度的升高,氧气扩散系数逐渐减少;在相同条件下,氧气在Na OH溶液中扩散系数小于在KOH溶液中的扩散系数;溶质离子扩散系数的变化规律与氧气一致.通过与现有实验结果对比,发现了分子动力学方法的可靠性及用于研究实验受限领域的优越性

    structureanddiffusivityofoxygeninconcentratedalkalimetalhydroxidesolutionsamoleculardynamicssimulationstudy

    No full text
    采用分子动力学方法对不同温度(25-120°C)及碱浓度(1:100-1:5,摩尔比)下Na OH和KOH溶液中的氧气进行了模拟.本文考察了Na OH及KOH溶液中溶剂-溶剂、氧气-溶剂及氧气-溶质的径向分布函数,并采用爱因斯坦方程从均方位移曲线中计算得到了氧气及溶质离子的扩散系数.结果显示随着碱浓度的升高,氧气扩散系数逐渐减少;在相同条件下,氧气在Na OH溶液中扩散系数小于在KOH溶液中的扩散系数;溶质离子扩散系数的变化规律与氧气一致.通过与现有实验结果对比,发现了分子动力学方法的可靠性及用于研究实验受限领域的优越性
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