Numerical Simulation of Chip Formation in Metal Cutting Process

In order to study the chip formation mechanism in metal cutting process, based on finite element software ABAQUS, the paper established finite element model and carried out numerical simulation on serrated chip formation of Ni-base superalloy GH4169 and ribbon chip formation of 45# steel respectively. In addition, this paper also analyzed the influence law of three factors (cutting speed, feed rate, back cutting depth) on cutting force and the distribution rule of cutting heat in serrated chip formation of GH4169

The 2021 FASEB science research conference on NAD metabolism and signaling

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A Probe into Spoken English Recognition in English Education Based on Computer-Aided Comprehensive Analysis

At present, computer-aided spoken English learning is becoming increasingly popular among learners. The computer-aided comprehensive analysis tech-nology can evaluate and correct learner's spoken pronunciation, thereby im-proving their pronunciation. Based on computer-aided comprehensive analy-sis, this paper aims to explore the automatic recognition and scoring methods of spoken English in English education. For this, it studies the effective matching of the feedback information with the known pronunciation scoring results, and then develops a computer evaluation plug-in consisting of dif-ferent modules such as user login, English spoken speech acquisition and recognition, voice evaluation, speech broadcast, and spoken dialogue. The research results show that the computer evaluation plug-in matches and compares the extracted feature parameters of input speech with the standard features, scores the spoken language input by the learner, and gives the cor-rect pronunciation so that the learner can get feedback in time. For different stages of English learning, the focus of recognition technology and the spo-ken recognition algorithms applied also vary. The research findings provide theoretical and technical support for oral English recognition, error correction and scoring

Effects of Supplemental Nucleotides, Taurine, and Squid Liver Paste on Feed Intake, Growth Performance, Serum Biochemical Parameters, and Digestive Enzyme Activities of Juvenile GIFT Tilapia (Oreochromis sp.) Fed Low Fishmeal Diets

This 8 week feeding trial evaluated the effects of three feeding stimulants (FS) on feed intake, growth performance, body composition, serum biochemical parameters, and digestive enzyme activities for juvenile GIFT tilapia fed low fishmeal diets. Four test diets were supplemented with 0, 16 g/kg taurine (Tau), 0.4 g/kg mixed nucleotides (Mix-NT), and 30 g/kg squid liver paste (SQLP) respectively, and fed to juvenile GIFT strain of Oreochromis niloticus (3.34±0.01 g). The results showed that feed intake (FI) significantly increased with SQLP. Specific growth rate (SGR) in fish fed SQLP or Mix-NT diet was significantly higher than that of the Tau and control group. The feed conversion ratio (FCR) ranged from 1.34 in the group fed Mix-NT to 1.50 in the group fed Tau, with no significant differences compared to the control group. Three feeding stimulants had no significant influence on whole body composition of tilapia. Fish fed Mix-NT diet showed significantly higher intestinal protease activity and intestinal amylase activity than that of other groups. High-density lipoprotein content in serum was significantly higher in fish fed SQLP diet than that of other groups. In conclusion, supplementation of 0.4 g/kg mixed nucleotides or 30 g/kg squid liver paste in low fishmeal diets could provide better growth performance for juvenile tilapia, and SQLP could act as an effective FS under these conditions. Supplementation of Mix-NT could reduce the FCR in these fish

Preparation of NiS/ZnIn2S4 as a superior photocatalyst for hydrogen evolution under visible light irradiation

In this study, NiS/ZnIn2S4 nanocomposites were successfully prepared via a facile two-step hydrothermal process. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Their photocatalytic performance for hydrogen evolution under visible light irradiation was also investigated. It was found that the photocatalytic hydrogen evolution activity over hexagonal ZnIn2S4 can be significantly increased by loading NiS as a co-catalyst. The formation of a good junction between ZnIn2S4 and NiS via the two step hydrothermal processes is beneficial for the directional migration of the photo-excited electrons from ZnIn2S4 to NiS. The highest photocatalytic hydrogen evolution rate (104.7 μmol/h), which is even higher than that over Pt/ZnIn2S4 nanocomposite (77.8 μmol/h), was observed over an optimum NiS loading amount of 0.5 wt %. This work demonstrates a high potential of the developing of environmental friendly, cheap noble-metal-free co-catalyst for semiconductor-based photocatalytic hydrogen evolution

Numerical Simulation of Chip Formation in Metal Cutting Process

In order to study the chip formation mechanism in metal cutting process, based on finite element software ABAQUS, establish finite element model, and carry out numerical simulation on serrated chip formation of Ni-base superalloy GH4169 and ribbon chip formation of 45# steel respectively.In addition, analyze the influence law of three factors (cutting speed, feed rate, back cutting depth) on cutting force and the distribution rule of cutting heat in serrated chip formation of GH4169.DOI: http://dx.doi.org/10.11591/telkomnika.v10i3.608

Evolution of the Probe-Based Loop-Mediated Isothermal Amplification (LAMP) Assays in Pathogen Detection

Loop-mediated isothermal amplification (LAMP), as the rank one alternative to a polymerase chain reaction (PCR), has been widely applied in point-of-care testing (POCT) due to its rapid, simple, and cost-effective characteristics. However, it is difficult to achieve real-time monitoring and multiplex detection with the traditional LAMP method. In addition, these approaches that use turbidimetry, sequence-independent intercalating dyes, or pH-sensitive indicators to indirectly reflect amplification can result in false-positive results if non-specific amplification occurs. To fulfill the needs of specific target detection and one-pot multiplex detection, a variety of probe-based LAMP assays have been developed. This review focuses on the principles of these assays, summarizes their applications in pathogen detection, and discusses their features and advantages over the traditional LAMP methods

Optimization of Processing Parameters and Adhesive Properties of Aluminum Oxide Thin-Film Transition Layer for Aluminum Substrate Thin-Film Sensor

A thin-film strain micro-sensor is a cutting force sensor that can be integrated with tools. Its elastic substrate is an important intermediate to transfer the strain generated by the tools during cutting to the resistance-grid-sensitive layer. In this paper, 1060 aluminum is selected as the elastic substrate material and aluminum oxide thin film is selected as the transition layer between the aluminum substrate and the silicon nitride insulating layer. The Stoney correction formula applicable to the residual stress of the aluminum oxide film is derived, and the residual stress of the aluminum oxide film on the aluminum substrate is obtained. The influence of Sputtering pressure, argon flow and negative substrate bias process parameters on the surface quality and sputtering power of the aluminum oxide thin film is discussed. The relationship model between process parameters, surface roughness, and sputtering rate of thin films is established. The sputtering process parameters for preparing an aluminum oxide thin film are optimized. The micro-surface quality of the aluminum oxide thin film obtained before and after the optimization of the process parameters and the surface quality of Si3N4 thin film sputtered on alumina thin film before and after the optimization are compared. It is verified that the optimized process parameters of aluminum oxide film as a transition layer can improve the adhesion between the insulating-layer silicon nitride film and the aluminum substrate

Dynamic immune response in the spleens of rainbow trout (Oncorhynchus mykiss) to infectious hematopoietic necrosis virus revealed by transcriptome and immune-related genes expression analysis

Rainbow trout (Oncorhynchus mykiss) is, economically, one of the most important cultured fish in the world. Infectious hematopoietic necrosis virus (IHNV) is a serious pathogen causing high morbidity and mortality in rainbow trout. To gain more insight into the immune response of rainbow trout to the virus, RNA sequencing technology was used to examine the transcriptome profiles in spleens of trout infected and uninfected with IHNV. A total of 9144 differentially expressed genes (DEGs) were identified, of which 3274 were upregulated and 5870 were downregulated. The expression levels of 13 DEGs were validated by quantitative real-time PCR. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis showed that most DEGs were significantly enriched in major immune terms such as immune system process, immune effector process, response to stimulus and key immune signaling pathways. Moreover, we detected the expression levels of six key immune-related genes based on transcriptomic data and protein–protein interaction analysis in four important immune signaling pathways at 0, 6, 12, 24, 48, 72, 96, 120, and 144 h post-infection, including Toll-like receptor signaling pathway (TLR2 and TLR5M), RIG-I-like receptor signaling pathway (TRIM25), NOD-like receptor signaling pathway (RIPK2 and A20) and JAK-STAT signaling pathway (SOCS2). Results revealed that the immune-related genes in these pathways were involved in the antiviral immune response. Altogether, this study provides a better understanding of the dynamic immune response of rainbow trout infected with IHNV, which will lay a foundation for further study of molecular mechanisms of anti-IHNV innate immunity

Study of the Pattern Preparation and Performance of the Resistance Grid of Thin-Film Strain Sensors

The thin-film strain sensor is a cutting-force sensor that can be integrated with cutting tools. The quality of the alloy film strain layer resistance grid plays an important role in the performance of the sensor. In this paper, the two film patterning processes of photolithography magnetron sputtering and photolithography ion beam etching are compared, and the effects of the geometric size of the thin-film resistance grid on the resistance value and resistance strain coefficient of the thin film are compared and analyzed. Through orthogonal experiments of incident angle, argon flow rate, and substrate negative bias in the ion beam etching process parameters, the effects of the process parameters on photoresist stripping quality, etching rate, surface roughness, and resistivity are discussed. The effects of process parameters on etching rate, surface roughness, and resistivity are analyzed by the range method. The effect of substrate temperature on the preparation of Ni Cr alloy films is observed by scanning electron microscope. The surface morphology of the films before and after ion beam etching is observed by atomic force microscope. The influence of the lithography process on the surface quality of the film is discussed, and the etching process parameters are optimized