Reactive SPS of Al2O3–RE:YAG (RE = Ce; Ce+Gd) composite ceramic phosphors

Ultrafine-grained Al2O3–rare earth:yttrium aluminium garnet (Al2O3–RE:YAG) (RE = Ce; Ce+Gd) composite ceramics were obtained for the first time by reactive spark plasma sintering (SPS) using commercially available initial oxide powders. The effect of key sintering parameters (temperature, dwell time, and external pressure (Pload)) on densification peculiarities, structural-phase states, and luminescent properties of composites was studied comprehensively. Differences in phase formation and densification between Ce-doped and Ce,Gd-codoped systems were shown. Parameters of reactive SPS, at which there is partial melting with the formation of near-eutectic zones of the Al2O3–YAG system/coexistence of several variations of the YAG-type phase, were established. Pure corundum–garnet biphasic ceramics with an optimal balance between microstructural and luminescence performance were synthesized at 1425 ℃/30 min/30–60 MPa. The external quantum efficiency (EQE) of the phosphor converters reached 80.7% and 72% with close lifetime of ~63.8 ns, similar to those of commercial Ce:YAG materials, which is promising for further applications in the field of high-power white light-emitting diodes (WLEDs) and laser diodes (LDs)

Chemotaxis of Cell Populations through Confined Spaces at Single-Cell Resolution

Cell migration is crucial for both physiological and pathological processes. Current in vitro cell motility assays suffer from various drawbacks, including insufficient temporal and/or optical resolution, or the failure to include a controlled chemotactic stimulus. Here, we address these limitations with a migration chamber that utilizes a self-sustaining chemotactic gradient to induce locomotion through confined environments that emulate physiological settings. Dynamic real-time analysis of both population-scale and single-cell movement are achieved at high resolution. Interior surfaces can be functionalized through adsorption of extracellular matrix components, and pharmacological agents can be administered to cells directly, or indirectly through the chemotactic reservoir. Direct comparison of multiple cell types can be achieved in a single enclosed system to compare inherent migratory potentials. Our novel microfluidic design is therefore a powerful tool for the study of cellular chemotaxis, and is suitable for a wide range of biological and biomedical applications

A Novel Malware Detection and Family Classification Scheme for IoT Based on DEAM and DenseNet

With the rapid increase in the amount and type of malware, traditional methods of malware detection and family classification for IoT applications through static and dynamic analysis have been greatly challenged. In this paper, a new simple and effective attention module of Convolutional Neural Networks (CNNs), named as Depthwise Efficient Attention Module (DEAM), is proposed and combined with a DenseNet to propose a new malware detection and family classification model. Based on the good effect of the DenseNet in the field of image classification and the visual similarity of the malware family on images, the gray-scale image transformed from malware is input into the model combined with the DEAM and DenseNet for malware detection, and then the family classification is carried out. The DEAM is a general lightweight attention module improved based on the Convolutional Block Attention Module (CBAM), which can strengthen the attention to the characteristics of malware and improve the model effect. We use the MalImg dataset, Microsoft malware classification challenge dataset (BIG 2015), and our dataset constructed by the two above-mentioned datasets to verify the effectiveness of the proposed model in family classification and malware detection. Experimental results show that the proposed model achieves 99.3% in terms of accuracy for malware detection on our dataset and achieves 98.5% and 97.3% in terms of accuracy for family classification on the MalImg dataset and BIG 2015 dataset, respectively. The model can reliably detect IoT malware and classify its families

The Retroflex Sound of Languages Spoken in Southeast Tibet: Feature Floating, Feature Recombination and Its Historical Typological Value

In Southeast Tibet, some Tibeto-Burman languages have apparent retroflex feature floating. Some initial research on this phenomenon shows that different sound categories, such as a post consonant r and retroflex vowels (or finals), are not totally independent. This feature is likely the result of the evolution of one sound category toward another, and the evolution mechanism is the feature recombination between r and the basic consonant. This research approach can be applied to studying the whole Sino-Tibetan historical typology, including Chinese and Tibeto-Burman languages

Research on the Irrational Behavior of Consumers’ Safe Consumption and Its Influencing Factors

Frequent food safety incidents in recent years have greatly reduced consumers’ trust, and consumers’ demand for safe food has been on the rise. However, there is an inconsistency between the consumers’ willingness and actual purchasing behaviors. Some consumers who have a willingness to purchase safe food ultimately do not produce actual purchasing behaviors, resulting in an “irrational behavior„ in the safe food consumer market. In order to better study this phenomenon and identify its inherent logic, we chose to use pork (a typical representative of safety-certified agricultural products) as the object, based on a survey on 844 consumers in the Jiangsu Province and Anhui Province analyzed in July 2017 by RPL (Random Parameters Logit) and binary Logit regression methods from two aspects, i.e. consumer preference for different attributes of safety-certified products and factors affecting safe consumption. The research results show that consumers have a significant preference for pork that has additional attributes such as green food certification, organic food certification, origin information and “No Additives and Veterinary Drug Residue Labeling„; labeling such information on the pork can effectively improve consumers’ trust. Consumers’ inconsistency of purchase intention with purchasing behaviors of safety-certified pork is affected by many factors, such as gender, age, annual household income, the degree of trust in agricultural product quality and a safety certification mark, understanding of safety-certified pork, and the degree of concern on pork quality and safety issues. These factors have all contributed, to varying degrees, to the rising of “irrational behavior„ of consumers’ safe consumption, lead to an irrational state of consumption that consumers with a safely certified pork purchase will not necessarily buy a safety-certified pork. Based on the results of two empirical analyses, it can be concluded that pricing and age are the two main influencing factors that lead to the “irrational behavior„ of consumers’ safe consumption

Recognition of Consumers’ Characteristics of Purchasing Farm Produce with Safety Certificates and Their Influencing Factors

In order to alleviate the situation that bad money drives out good in the produce market within the context of incomplete information, as well as bridge the gap between demand and product surplus, establishing and improving the safety certification system for farm produce is an urgent need. This paper discusses factors that affect consumers’ purchase of pork with safety certificates in the setting of incomplete information. Data from 844 consumers in Jiangsu and Anhui provinces, along with a structural equation model, are adopted to study consumers’ purchase intention of certified safe pork form. According to our studies, major factors refer to degree of understanding, degree of concern, recognition ability, government publicity, pork’s origin information, consumers’ educational levels, income levels, and consumers’ evaluation of government supervision. Accordingly, suggestions are provided as follows. Above all, enhancing education and training of food safety is conducive to lead consumers’ behaviors in a correct way. Next, news media and social public opinions can play a stronger role in guidance and supervision. Thirdly, an upgraded legal system should be accompanied by better policy implementation. Finally, strengthening the origin certification system and promoting a sense of brand are of significance

A Study on the Influence of Different Constraint Modes and Number of Disc Springs on the Dynamics of Disc Spring System

In this work, the influences of constraint modes and the number of disc springs on the dynamic characteristics of the disc spring system are studied by simulation and experiment. The amplitudes and amplification factors of the disc spring system under different constraint modes and different numbers of disc springs are obtained. The results show that the maximum amplitude and amplification factor both appear at the constraint modes of locking and no preloading, which indicates that the locking and no preloading is the best constraint mode among the four different constraint modes. Moreover, the amplitude of the disc spring system first increases and then decreases with the number of disc springs increasing, while the amplification factor increases with the number of disc springs increasing. The maximum amplification factor (10.21 in experiment) of the disc spring system appears at 10 disc springs. By studying the relationship between the number of disc springs and amplification factor and damping, we find that the damping of the disc spring system can be reduced by increasing the disc spring numbers, and thus, the corresponding amplification factor can be improved. Furthermore, as the number of disc spring increases, the height differences of disc springs before and after locking are all close to 3 mm, which indicates that the amount of locking compression in the assembly process has a good consistency when the number of disc springs changes. The aforementioned works can provide guidance for the industrial production in screen vibration