64 research outputs found

    Preparation and Anticorrosion of Octadecyl Trichlorosilane SAMs for Copper Surface

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    The self-assembled monolayer (SAM) was prepared using octadecyl trichlorosilane (OTS) in distilled solution on the copper surface. The effect of inhibitor concentration on the rate of inhibition efficiency and corrosion rate in corrosion medium on copper by using polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM) was studied. The results showed that OTS SAMs exhibit the better corrosion resistance; the corrosion potential of copper OTS SAMs protection increased by about 1.02 V, while the corrosion current density decreased to 0.59 μA/cm2. The corrosion rate is minimized and flattened and can reach 9.2% while the inhibition efficiency reached 95.4%, when the corrosion inhibitor has concentration of 40 ppm

    A Temporal-Pattern Backdoor Attack to Deep Reinforcement Learning

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    Deep reinforcement learning (DRL) has made significant achievements in many real-world applications. But these real-world applications typically can only provide partial observations for making decisions due to occlusions and noisy sensors. However, partial state observability can be used to hide malicious behaviors for backdoors. In this paper, we explore the sequential nature of DRL and propose a novel temporal-pattern backdoor attack to DRL, whose trigger is a set of temporal constraints on a sequence of observations rather than a single observation, and effect can be kept in a controllable duration rather than in the instant. We validate our proposed backdoor attack to a typical job scheduling task in cloud computing. Numerous experimental results show that our backdoor can achieve excellent effectiveness, stealthiness, and sustainability. Our backdoor's average clean data accuracy and attack success rate can reach 97.8% and 97.5%, respectively

    Public-Private Partnership in Infrastructure Development - Case Studies from Asia and Europe

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    Development of infrastructure projects with private engagement through PPP has become one of the commonly adopted procurement strategies in developed and developing countries. All over the world where PPP procurement has been used in one form or another, the way in which it is carried out has become an important issue. Yet, there is no standard method of PPP implementation as each country adapts the process as appropriate for its own culture, economy, political climate and legal system. It is therefore essential that all parties likely to be involved have a common understanding of the principles underlying PPP structures and an appreciation of the key issues from the standpoints of the private as well as the public sectors. PPP projects with substantial private investments involve participation of stakeholders with diverse perspectives, which can lead to different perceptions on the viability of the project. The introduction chapter covers the general issues of PPP implementation and presents an overview of the use of PPP in the delivery of public infrastructure and services across the world. Following, in five case studies PPP projects from Asia and Europe are presented and reveal differences in the respective approaches of each country. The case studies analyze project objectives, scope and site as well as legal, contractual and financial framework under which the projects were realized. Each case study closes with a chapter discussing the different approaches and summarizing lessons learned

    Fractal characteristics of acoustic emission of gas-bearing coal subjected to true triaxial loading

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    As coal mining proceeds deeper, coal and rock are subjected to growing stresses and gas pressures. Consequently, coal and rock gas dynamic disasters pose more and more considerable threats and hazards which should be warned in advance. Coal and rock in the field is actually in the true triaxial stress state. Study on deformation characteristics and precursory information of coal and rock under this state is meaningful for disaster warning. In this paper, experiments on the deformation, failure and acoustic emission (AE) characteristics of gas-bearing coal under true triaxial loading conditions were carried out. Besides, the variation law and fractal characteristics of AE under different gas pressures and confining stresses were analyzed. Furthermore, the effects of gas pressure and confining stress on the deformation, failure and fractal characteristics of coal were discussed. The results show that the process of AE variation under true triaxial loading conditions can be divided into two stages, namely the slow growth stage and the accelerated growth stage. A higher gas pressure corresponds to a shorter duration of slow growth stage, while a higher confining stress corresponds to a longer duration of slow growth stage. AE time series has fractal characteristics, and the correlation dimension can characterize the damage degree of a loaded coal sample. The dynamic changes, i.e., fluctuation-increase-decrease, in correlation dimension can accurately reflect the damage evolution process of a coal sample. In addition, the gradual reduction of correlation dimension can be used as the precursor information of coal sample instability and damage. The research results boast instructive significance for preventing the occurrence of coal and rock gas dynamic disasters and for reducing casualties and property loss in coal mines

    A rational design of highly active and coke-resistant anode for methanol-fueled solid oxide fuel cells with Sn doped Ni-Ce0.8Sm0.2O2−δ

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    A crucial challenge in the commercialization of Ni-based materials as the anode of solid oxide fuel cell is the fast voltage drop due to carbon deposition and structural degradation during cell operation. Herein, Sn-doped Ce0.8Sm0.2O2−δ (SDC) supported Sn-Ni alloy anode is rationally designed and prepared, via a simple and convenient dual-modification strategy. The substitution of Sn of Ce in the oxide phase enhances the mobility of lattice oxygen in SDC. Meanwhile, Sn exsolves partially from the oxide phase and forms Ni3Sn and Ni3Sn2 intermetallic compounds with Ni after reduction. The composite anode thus formed achieves unprecedent activity in the electrochemical oxidation of H2 and CH3OH. The maximum power densities of a cell supported by 500 μm-thick Ce0.8Sm0.2O2−δ-carbonate electrolyte layer with the Ni-Ce0.7Sn0.1Sm0.2O2−δ (Ni-SSn10DC) anode reach 1.99 and 2.11 W cm−2 at 700 °C, respectively for using H2 and methanol as fuels. The doping of Sn also remarkably enhances the coking resistance of the anode.This work opens a path on the design of high-performance SOFC anode.Peer reviewe

    Meteorin-Like Shows Unique Expression Pattern in Bone and Its Overexpression Inhibits Osteoblast Differentiation.

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    The present study was performed to identify and characterize genes involved in osteoblasts function. Firstly, we constructed and sequenced a human osteoblast full-length cDNA library to screen for genes whose functions have not been reported and further identify these candidate genes through detecting the relationship with the activator protein-1 (AP-1) transcription factor complex using a dual luciferase reporter system. Only one gene, namely METRNL (Meteorin, glial cell differentiation regulator-like) has been screened out. We performed immunohistochemistry to analyze expression patterns in bone and established a stable transfection MG63 cell line of METRNL-EGFP fusion protein overexpression to analyze the function of METRNL in mineralized nodule formation. Immunohistochemistry showed METRNL expression in hypertrophic chondrocytes and osteoblasts lining trabecular bone surfaces. Overexpression of METRNL inhibited mineralized nodule formation by the MG63 osteosarcoma cell line. Thus, the identified gene, METRNL, which is associated with AP-1 transcription factor complex activity, has a unique expression pattern in bone. In addition, the anomalous expression of METRNL may inhibit bone cell differentiation

    Effects of insufficient physical activity on mortality and life expectancy in Jiangxi province of China, 2007-2010.

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    BACKGROUND: Physical inactivity remains an under-researched field in terms of studying burden of disease at provincial level, and no studies have examined the effects of inactivity on life expectancy (LE) in China. The purpose of this study was to estimate mortality risk and LE effects associated with insufficient levels of physical activity in Jiangxi province. METHODS/FINDINGS: Prevalence of risk factors and mortality counts were extracted from Chronic Diseases and Risk Factors Surveillance Survey (CDRFSS) and Disease Surveillance Points system (DSP), respectively. Insufficient physical activity (IPA) was defined as less than 150 minutes of moderate-intensity physical activity or 60 minutes of vigorous-intensity physical activity per week, accumulated across work, home, transport and discretionary domains. Population-attributable fractions (PAF) were used to calculate the mortality attributable to risk factors, and life table methods were used to estimate the LE gains and LE shifts. Monte Carlo simulation techniques were used for uncertainty analysis. Overall, 5 885 (95% uncertainly interval (UI), 5 047-6 506) and 8 578 (95% UI, 8 227-9 789) deaths in Jiangxi province were attributable to IPA in 2007 and 2010, respectively. The LE gains for elimination of attributable deaths were 0.68 (95% UI, 0.61-076) in 2007, and increased to 0.91 (95% UI, 0.81-1.10) in 2010. If the prevalence of IPA in 2010 had been decreased by 50% or 30%, 3 678 (95% UI, 3 220-4 229) or 2 090 (95% UI, 1 771-2 533) deaths would be avoided, and 0.40 (95% UI, 0.34-0.53) or 0.23 (95% UI, 0.16-0.31) years of LE gained, respectively. CONCLUSIONS: Adults in Jiangxi province of China have a high and increasing prevalence of IPA. Due to the deaths and potential LE gains associated with IPA, there is an urgent need to promote physical activity, one of the most modifiable risk factors, within China's health care reform agenda
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