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Post deposition annealing effect on properties of Y2O3/Al2O3 stacking gate dielectric on 4H-SiC
No full textIn this paper, the effect of post deposition annealing (PDA) on the chemical, structural, and electrical properties of the high-k Y 2 O 3 /Al 2 O 3 stacking dielectric on p-type 4H-SiC were studied. High-k dielectric provides a physically thicker film with equivalent capacitance, therefore better exploits the high breakdown strength of 4H-SiC in its MOSFET devices. The Y 2 O 3 /Al 2 O 3 stacking films were deposited using RF magnetron sputtering, with PDA in Ar ambient at 400 °C, 600 °C, 800 °C and 1000 °C. X-ray diffraction (XRD) and angle resolved X-ray photoelectron spectroscopy (XPS) results show that an Al 5 O 12 Y 3 crystal layer was formed in between Y 2 O 3 and Al 2 O 3 films after annealing above 600 °C. High resolution transmission electron microscope (HRTEM) was used to investigate the atomic structure and measure the thickness of each layer. Charges and dielectric strength of the stacking films were characterized by high frequency capacitance-voltage (C-V) and current-voltage (I-V) measurements. The lower charge density and higher dielectric strength were found after PDA at 800 °C and 1000 °C
Barriers of Biodiesel Adoption by Transportation Companies: A Case of Malaysian Transportation Industry
No full textThe need to develop an alternative fuel to fossil fuel is growing day by day, especially for the transportation industry, as the supply of fossil fuels is limited and is depleting at a rapid rate. One available resource that has emerged recently is biodiesel. However, the usage of biodiesel is very low among transportation companies. An investigation into the barriers of adopting biodiesel by transportation companies is the focus of the present study. A survey of 147 transportation companies in Malaysia was undertaken, and the data gathered were analyzed using partial least squares technique. Lack of government support, lack of environmental-commercial benefits, and lack of competitive pressure were found to be the barriers to biodiesel adoption. The results also indicated that differentiation strategy moderates the impact of lack of government support, lack of customer demand, lack of environmental-commercial benefits and lack of competitive pressure on biodiesel adoption. The results of this study could benefit policy makers by providing them key focus areas in which they can modify their strategies to actively and successfully promote the use of biodiesel among transportation companies in developing countries
Metabolic and physiological regulation of Chlorella sp. (Trebouxiophyceae, Chlorophyta) under nitrogen deprivation
No full textA freshwater green microalgae Chlorella sp., UMACC344 was shown to produce high lipid content and has the potential to be used as feedstock for biofuel production. In this study, photosynthetic efficiency, biochemical profiles and non-targeted metabolic profiling were studied to compare between the nitrogen-replete and deplete conditions. Slowed growth, change in photosynthetic pigments and lowered photosynthetic efficiency were observed in response to nitrogen deprivation. Biochemical profiles of the cultures showed an increased level of carbohydrate, lipids and total fatty acids, while the total soluble protein content was lowered. A trend of fatty acid saturation was observed in the nitrogen-deplete culture with an increase in the level of saturated fatty acids especially C16:0 and C18:0, accompanied by a decrease in proportions of monounsaturated and polyunsaturated fatty acids. Fifty-nine metabolites, including amino acids, lipids, phytochemical compounds, vitamins and cofactors were significantly dysregulated and annotated in this study. Pathway mapping analysis revealed a rewiring of metabolic pathways in the cells, particularly purine, carotenoid, nicotinate and nicotinamide, and amino acid metabolisms. Within the treatment period of nitrogen deprivation, the key processes involved were reshuffling of nitrogen from proteins and photosynthetic machinery, together with carbon repartitioning in carbohydrates and lipids
Environmental dimension of regional development in China, with special focus on grassland ecological compensation in Alxa League of Inner Mongolia
No full textThere are four characteristics typical of the distribution of China’s population in poverty: (1) concentration in the mountainous areas; (2) concentration in the western region; (3) concentration in environmentally fragile areas; (4) concentration in ethnic minority areas. In particular, poverty in this large country is very much related to environmental factors. Out of the country’s 592 poverty counties, 366 are in the western region, and most of these poverty counties are distributed over several major areas of fragile environmental habitat, including among others Inner Mongolian plateau’s southeastern border area that suffers from desertification. The paper focuses on poverty in China’s western region, its determining factors especially environmental degradation that is dominated by the three main issues of soil erosion, desertification and grassland deterioration, and State policies to overcome these problems, and includes a specific case study of the grassland ecological compensation policy in the Alxa League of Inner Mongolia
Development of live attenuated Enterovirus 71 vaccine strains that confer protection against lethal challenge in mice
No full textBesides causing mild hand, foot and mouth infections, Enterovirus A71 (EV-A71) is associated with neurological complications and fatality. With concerns about rising EV-A71 virulence, there is an urgency for more effective vaccines. The live attenuated vaccine (LAV) is a more valuable vaccine as it can elicit both humoral and cellular immune responses. A miRNA-based vaccine strain (pIY) carrying let-7a and miR-124a target genes in the EV-A71 genome which has a partial deletion in the 5′NTR (∆11 bp) and G64R mutation (3D p ° l ) was designed. The viral RNA copy number and viral titers of the pIY strain were significantly lower in SHSY-5Y cells that expressed both let-7a and miR-124a. Inhibition of the cognate miRNAs expressed in RD and SHSY-5Y cells demonstrated de-repression of viral mRNA translation. A previously constructed multiply mutated strain, MMS and the pIY vaccine strain were assessed in their ability to protect 4-week old mice from hind limb paralysis. The MMS showed higher amounts of IFN-γ ex vivo than the pIY vaccine strain. There was absence of EV-A71 antigen in the skeletal muscles and spinal cord micrographs of mice vaccinated with the MMS and pIY strains. The MMS and pIY strains are promising LAV candidates developed against severe EV-A71 infections. © 2019, The Author(s)
Study on Flow Behavior and Heat Exchange Characteristics of a Capillary Tube-Suction Line Heat Exchanger
No full textThe present research is to develop a homogenous mathematical model to simulate capillary tube-suction line heat exchanger (CT-SL HX) based on the fundamentals of conservations of mass, momentum and energy with comprehensive experimental result validations. The computer model is fully validated by 72 experimental data with error bands of ±15%, ±2°C and ±35% on the mass flow rate prediction, the suction pipe outlet temperature, and the heat exchange estimation respectively. The results suggest that the internal diameter of the capillary tube, and the heat-transfer length of the CT-SL HX have demonstrated an apparent impact on the capillary tube outlet conditions and heat transfer across the segment. © 2018, © 2018 Taylor & Francis Group, LLC
Sodium nitrate (NaNO3) sensor based on graphene coated microfiber
No full textWe demonstrate the coating of graphene onto the silica optical microfiber sensor for improving sodium nitrate detection at room temperature. The graphene obtained from graphene- polylactic acid filament was coated onto the microfiber based on drop casting technique. In the proposed sensor, the graphene acts as cladding to interact with analyte as well as functions to trap either sodium cation or nitrate anion and increases the effective refractive index of the cladding. The proposed sensor shows a good sensitivity of 1.29 dBm/% and resolution of 0.049%. The sensitivity, repeatababilty and reversible response of the sensor were improved by the coating of graphene layer. The presence of graphene on the surface microfiber works as passive cladding and influence the light propagation through the microfiber. © 2019 Elsevier Lt
Ductility behaviours of oil palm shell steel fibre-reinforced concrete beams under flexural loading
No full textIn the effort of developing sustainable concrete, studies on the replacement of conventional coarse aggregates with local waste material are increasing. The new oil palm shell fibre-reinforced concrete (OPSFRC) utilises Malaysia’s waste material and is emerging as a promising sustainable concrete attributed to its lightweight and enhanced concrete properties. In this study, the flexural behaviours of OPSC and OPSFRC beams (with steel fibres.25,.50,.75 and 1.00% by volume) were investigated. The results show that the addition of steel fibres improved both the mechanical properties and moment capacities of OPSFRC specimens. However, the OPSFRC exhibited reduced deflection at failure of about 30–40% relative to the OPSC beams. Meanwhile, the steel fibres significantly improved the failure load to ultimate load ratios of OPSFRC to.65–.80 compared to the ratio of.19 as in OPSC. In addition, different approaches to compute the ductility ratios of OPSFRC beams are also conducted and compared. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group
Circulating adiponectin as a biomarker in renal cell carcinoma: a systematic review and meta-analysis
No full textContext: Metabolic imbalance in renal cell carcinoma (RCC) can lead to abnormal adiponectin levels. Objective: To evaluate circulating adiponectin as a detection or predictive marker for RCC. Methods: A comprehensive literature search and meta-analysis was performed on studies reporting circulating adiponectin levels and RCC. The meta-analysis was performed using RevMan. Results: Seven studies compared the circulating adiponection levels between RCC cases and controls. Adiponectin level was significantly lower in RCC cases compared to controls at pre-diagnosis and pre-operative time-points. RCC stage, grade and subtype did not affect adiponectin levels. Conclusion: Low circulating adiponectin could be a predictive or risk factor for RCC. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group
The Effect of Incorporation of Multi-Walled Carbon Nanotube into Poly(Ethylene Oxide) Gel Electrolyte on the Photovoltaic Performance of Dye-Sensitized Solar Cell
No full textGel polymer electrolytes (GPEs) consist of poly(ethylene oxide) (PEO), sodium iodide (NaI) and different amount of multi-walled carbon nanotubes (MWCNT) were prepared. The conductivity study revealed that the highest ionic conductivity of GPE was 7.02 × 10−3 S cm−1. The structural and complexation between the materials are authenticated via X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Under the exposure of AM 1.5, the fabricated DSSCs exhibited the highest photoenergy conversion efficiency of 7.23% with a short circuit current density (JSC) of 18.64 mA cm−2, open circuit voltage (VOC) of 0.590 mV and fill factor (FF) of 65.7%. © 2018 Taylor & Francis