L2L_2BN: Enhancing Batch Normalization by Equalizing the L2L_2 Norms of Features

In this paper, we show that the difference in $l_2$ norms of sample features can hinder batch normalization from obtaining more distinguished inter-class features and more compact intra-class features. To address this issue, we propose an intuitive but effective method to equalize the $l_2$ norms of sample features. Concretely, we $l_2$-normalize each sample feature before feeding them into batch normalization, and therefore the features are of the same magnitude. Since the proposed method combines the $l_2$ normalization and batch normalization, we name our method $L_2$BN. The $L_2$BN can strengthen the compactness of intra-class features and enlarge the discrepancy of inter-class features. The $L_2$BN is easy to implement and can exert its effect without any additional parameters or hyper-parameters. Therefore, it can be used as a basic normalization method for neural networks. We evaluate the effectiveness of $L_2$BN through extensive experiments with various models on image classification and acoustic scene classification tasks. The results demonstrate that the $L_2$BN can boost the generalization ability of various neural network models and achieve considerable performance improvements

Growth of carbon nanowalls at atmospheric pressure for one-step gas sensor fabrication

Carbon nanowalls (CNWs), two-dimensional "graphitic" platelets that are typically oriented vertically on a substrate, can exhibit similar properties as graphene. Growth of CNWs reported to date was exclusively carried out at a low pressure. Here, we report on the synthesis of CNWs at atmosphere pressure using "direct current plasma-enhanced chemical vapor deposition" by taking advantage of the high electric field generated in a pin-plate dc glow discharge. CNWs were grown on silicon, stainless steel, and copper substrates without deliberate introduction of catalysts. The as-grown CNW material was mainly mono- and few-layer graphene having patches of O-containing functional groups. However, Raman and X-ray photoelectron spectroscopies confirmed that most of the oxygen groups could be removed by thermal annealing. A gas-sensing device based on such CNWs was fabricated on metal electrodes through direct growth. The sensor responded to relatively low concentrations of NO2 (g) and NH3 (g), thus suggesting high-quality CNWs that are useful for room temperature gas sensors

Experimental study on flue gas foam-assisted steam flooding: investigating characteristics of enhanced oil recovery and gas storage

Steam flooding is one of the most widely used heavy oil thermal recovery technologies. Steam transfers heat to heavy oil to reduce viscosity and improve fluidity. The current problem is that steam loses a lot of heat in the formation, and there are serious carbon emissions in the whole production process. In this paper, flue gas and steam were combined to drive heavy oil in the form of composite thermal fluid, and foam was added on this basis. With the help of one-dimensional sandpack model, both single-model and parallel dual-model with permeability ratio experiments were conducted to investigate key characteristics such as steam heat transfer, heavy oil production and flue gas retention during the displacement process. The experimental results indicated that flue gas effectively inhibited steam condensation and reduced heat loss during the flow process. Compared to steam flooding, the sandpack model exhibited temperature rises of 4.4°C and 9.1°C at the middle and end, respectively. While flue gas foam fell slightly short of flue gas in terms of enhanced heat transfer, it outperforms in recovery factor, achieving a 10.4% improvement over flue gas-assisted steam flooding. The foam blocked gas channeling by accumulating and capturing along the flow path, resulting in a gas retention volume of 389 mL within the model. Furthermore, the flue gas foam facilitated steam flow to previously unswept low-permeability areas, thus enhancing oil recovery. In the parallel double-model experiment, the low-permeability model exhibited significantly improved oil displacement efficiency compared to flue gas-assisted steam flooding, and the remaining oil content in the end of the high permeability model was increased by 1.9%, while the remaining oil content in the front and end of the low-permeability model was reduced by 3.5% and 3.8% respectively

Longitudinal associations of concurrent falls and fear of falling with functional limitations differ by living alone or not

BackgroundFalls and fear of falling (FOF) are independent risk factors for functional limitations in older adults. However, the combined effect of falls and FOF on functional limitations and the moderating role of living alone or not is unclear. We aimed to examine (1) the independent and combined effect of falls and FOF on functional limitations in older adults and (2) whether living alone moderates these associations.MethodsWe used data from the National Health and Aging Trends Study (NHATS) and included 5,950 U.S. community-dwelling older adults aged 65 and older from Round 1 (Year 2011) and Round 2 (Year 2012). Falls and FOF were ascertained by asking participants whether they had any falls in the last year and whether they had worried about falling in the previous month at R1. Assessed functional limitations included any difficulties with mobility, self-care, or household activities at R2. Poisson regression models were used to examine the longitudinal associations of falls and FOF with functional limitations and the moderation effects of baseline living alone.ResultsOf the 5,950 participants, 16.3% had falls only; 14.3% had FOF only; 14.3% had both, and 55.1% had neither at baseline. In the adjusted model, those who experienced concurrent falls and FOF in R1 had a higher risk of functional limitations at R2 than those with neither (Mobility: Incidence risk ratio [IRR] = 1.34, 95% CI: 1.24–1.45; Self-care: IRR = 1.18, 95% CI: 1.11–1.26; Household: IRR = 1.20, 95% CI: 1.11–1.30). Moreover, living alone significantly moderated the longitudinal associations of concurrent falls and FOF with mobility activity limitations.ConclusionThe findings suggest that strategies to improve falls and FOF together could potentially help prevent functional limitations. Older adults who live with others and have falls or FOF should receive interventions to promote their mobility activities

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Protein Viability on Au Nanoparticles during an Electrospray and Electrostatic-Force-Directed Assembly Process

We study the protein viability on Au nanoparticles during an electrospray and electrostatic-force-directed assembly process, through which Au nanoparticle-antibody conjugates are assembled onto the surface of carbon nanotubes (CNTs) to fabricate carbon nanotube field-effect transistor (CNTFET) biosensors. Enzyme-linked immunosorbent assay (ELISA) and field-effect transistor (FET) measurements have been used to investigate the antibody activity after the nanoparticle assembly. Upon the introduction of matching antigens, the colored reaction from the ELISA and the change in the electrical characteristic of the CNTFET device confirm that the antibody activity is preserved during the assembly process