bluuebunny/crossref_metadata_2025 huggingface dataset:
New insights on the Late Paleocene − Early Eocene dinoflagellate cyst zonation for the Paris and Dieppe basins
Authors: Iakovleva Alina I. , Quesnel Florence , Dupuis Christian
Published: September 2021

The Anglo-Belgo-Paris Basin, historical cradle of the Paleogene stratigraphy since the 19th century, is known by the presence of very specific so-called “Sparnacian” deposits (very diverse and laterally highly variable, predominantly lagoonal to terrestrial facies), which encompass the short stratigraphic interval of the Paleocene-Eocene Thermal Maximum (PETM). Due to the insufficient nature of the paleontological record, the “Sparnacian” succession of the Paris and Dieppe-Hampshire basins still needs to be robustly chronostratigraphically correlated with other Paleogene records worldwide. In order to refine the stratigraphy of the Thanetian-Lower Ypresian succession in northern France a number of cores and outcrop sections have been investigated palynologically. As a result, an updated version of the dinoflagellate cyst zonation for the Paris and Dieppe basins is proposed and contains six new or revised biozones for this stratigraphical interval:Alisocysta margarita,Apectodinium hyperacanthum,Apectodinium-acme,Biconidinium longissimum-acme,Dracodinium astra, andAxiodinium lunare/Stenodinium meckelfeldense. Based on combined bio-, litho- and chemostratigraphic data, it appears that the dinocyst assemblages, corresponding to the PETM event interval (“Sparnacian” deposits, Soissonnais and upper Mortemer formations), are characterized by an acme ofApectodiniumspp. (70–98%) in both basins, sometimes alternating with an acme of a few gonyaulacoid groups in the Dieppe Basin. Dinocyst assemblages from the PETM interval contain a significant number of atypical, longer specimens ofApectodinium parvum, which could represent an ecological onshore substitute forAxiodinium augustumin the Paris and Dieppe-Hampshire basins. The establishment of a newBiconidinium longissimum-acme Zone suggests that the stratigraphic hiatus previously inferred within this sequence in the Paris Basin does not exist.
Research on Key Technology and Technical and Economic Indicators of 220kV Prefabricated Cabin Substation
Authors: Chen Yang , Haibo Zhao , Shixuan He , Huiqing Liu , Hongtao Xu , Xiying Fan
Published: September 2021

The prefabricated cabin substation is a new type of intelligent substation integrating environmental protection, energy saving, high efficiency and economy. In view of the characteristics of the prefabricated cabin intelligent substation, its differences with conventional substations in terms of modularity and intelligent design are compared, the advantages of the prefabricated cabin substation are summarized, the key technology research of the cabin design is carried out, and its technical and economic indicators are analyzed. The research results show that, compared with conventional standardized substations, the use of prefabricated cabin substation mode can effectively improve the space utilization rate and the flexibility of station construction, the construction area can be reduced by 19%, the construction period is shortened by about 30%, and the cost is reduced by 5.35%, which has good economic and practical value.
Analysis of the Problems in the Intermediary Service of Science and Technology in the New Energy Industry
Authors: Pei Shanshan
Published: September 2021

In recent years, China’s new energy industry has made many important achievements in scientific and technological innovation, independent research and development and patent applications have been developed rapidly, but the disconnection of scientific and technological achievements is still prominent. Science and technology intermediaries can play an important role in promoting the cooperation between innovation subjects and the transformation of scientific and technological achievements. On the basis of summarizing the types and contents of science and technology intermediary services in China, this paper makes a more in-depth analysis on the existing problems of science and technology intermediary services in China’s new energy industry. Through the analysis of the problems, we hope to provide some theoretical basis and decision-making reference for the construction of China’s science and technology intermediary service system, and further improve the level of scientific and technological achievements transformation of new energy industry.
Combination Forecasting Method of Ship Maintenance Cost Based on Integrated Weighting
Authors: Wang Chengyu , Lin Mingchi , Tang Zheng
Published: September 2021

In view of the existing combination forecasting methods based on rough set theory that may not be able to weight individual individual forecasting models, the attribute importance in the original method is adjusted and combined with the root mean square error of the individual forecasting model to form a new attribute importance. The new attribute importance is used to determine the combination forecasting weight coefficients, which solves the problem that the original method cannot be weighted, and increases the consideration of forecasting accuracy. Weight coefficients are also determined according to the historical forecasting performance of the models, which reflects the forecasting stability of the models. The integrated weighting method is used to fuse the two kinds of weight coefficients. Based on a certain type of ship maintenance cost data example, the improved method is compared with the commonly used combined forecasting methods, and better results are obtained, the accuracy and stability of the forecasting are improved, and the effectiveness of the method is verified.
Government Intervention, Nature of Ownership and Enterprise Investment Efficiency——An Empirical Research Based on Panel Data Analysis
Authors: Lin Menghao
Published: September 2021

In the critical stage of economic transformation and upgrading, the government has a strong incentive to intervene in the investment behaviour of enterprises under the double assessment of political and economic indicators. This paper found that government intervention has a significant impact on enterprise investment, by providing financial support and other means to promote enterprises to expand investment, but due to the lack of effective guidance, it turns into over-investment. After further distinguishing the nature of ownership between state-owned enterprises and non-state-owned enterprises, the phenomenon that government intervention affects enterprise investment is more obvious in state-owned enterprises, which is reflected in promoting over-investment and restraining under-investment. Therefore, government intervention will affect the investment efficiency of state-owned enterprises to a greater extent and make them develop in the direction of over-investment. This paper provides an overall perspective to explore the impact of government intervention on enterprise investment behaviour under the rapid economic growth.
Can executive equity incentives promote high-quality development of enterprises? —— Mediating effect based on innovation
Authors: Cai Linya , Luo Huawei
Published: September 2021

High quality is the direction of development, innovation drives high-quality development, and interest incentives drive innovation. Existing studies have shown that executive equity incentives can increase the financial performance of enterprises. Therefore, can executive equity incentives promote the high-quality development of enterprises, thereby improving the quality of industrial development? This paper takes China’s knowledge-intensive enterprises as a sample from 2015 to 2019. On the basis of using the LP semiparametric estimation method to measure the total factor productivity of the enterprise, in accordance with the intermediary effect test procedure, the stepwise regression method is used to study the innovation-driven effect of the executive equity incentives on the quality of enterprise development. The study found that executive equity incentives have an inverted U-shaped impact on the high-quality development of companies, with 20% being the optimal ratio. There is a partial mediating effect in corporate innovation activities on this transmission path. Based on this, suggestions are made to share residual income with senior management and build a high-quality innovative production chain.
The Application of “Big Data Analysis + Hierarchical Medical” Model in the Context of the COVID-19
Authors: Yang Xingyu , Yan Tianyu , Huang Zelong , Zhang Xiaofang , Zhao Yuchen , Jin Zihao
Published: September 2021

The COVID-19 epidemic has swept the world, causing serious impact and influence on economic development and residents' life in countries all over the world. This paper takes China as an example, further analyses the characteristics of China's hierarchical medical model based on the international hierarchical medical research planning, and proposes the application of “big data analysis + hierarchical medical” model for the new coronavirus epidemic and other public health emergencies based on the advantages of big data application to solve public health crises, in order to provide a reference for the planning of hierarchical medical system during the epidemic. It is expected to provide reference for the planning of hierarchical medical and health system during the epidemic, which is an innovative attempt of the medical industry.
Research on the development and competitiveness evaluation of manufacturing industry in Yangtze River Economic Belt
Authors: Wang Zongguang , Jiang Yamin
Published: September 2021

To promote the high-quality development of the Yangtze River economic belt is a major development strategy in China. As the lifeblood of the national economy, manufacturing industry is of great significance to realize the high-quality development of the Yangtze River economic belt. Based on the analysis of the overall situation of the manufacturing industry in the Yangtze River economic belt and the diamond model theory, this paper constructs an evaluation index system of manufacturing industry competitiveness with 4 first-class indexes and 16 second-class indexes, comprehensively evaluates the manufacturing industry competitiveness of each region by entropy method, and ranks the whole country. The results show that the manufacturing competitiveness of 11 provinces and cities in the Yangtze River economic belt is quite different and has obvious regional characteristics. The competitiveness of manufacturing industry in downstream regions is strong, while that in Yunnan and Guizhou provinces is weak, ranking at the bottom. Through in-depth analysis, it is found that there are some problems, such as unbalanced development, homogenization of industry, unreasonable layout of manufacturing industry. Combined with the development experience of excellent manufacturing industry and the regional characteristics of the Yangtze River economic belt, this paper proposes that we should speed up the industrial agglomeration, adhere to the innovation driven strategy, optimize the industrial layout and other ways to enhance the manufacturing competitiveness of the Yangtze River economic belt and promote the high-quality development of the Yangtze River economic belt.
Empirical Analysis of the Influence of Dongguan’s Modern Logistics Industry on Import and Export Trade
Authors: Xiaoqin Luo , Weiyu Xu , Jiabiao Shi
Published: September 2021

In recent years, with the rapid economic development and the deepening of global economic integration, import and export trade has developed rapidly. With the development of international trade, international logistics has emerged. Modern logistics is a necessity for import and export trade, and the development of logistics has a direct influence on the development of import and export. In order to adapt to the rapid development of import and export trade, the modern logistics industry is developing in the direction of quality, diversity and efficiency. As the manufacturing capital, Dongguan has great potential for trade development. Relying on the superior geographical environment and the original industrial system, and further integrating resources on this basis, Dongguan vigorously develops its modern logistics industry and promotes a high degree of connection between international trade and characteristic industries, promoting the development of Dongguan’s import and export trade. Taking Dongguan as the research object and combining the data of Dongguan’s import and export trade and modern logistics industries, this paper established a quadratic curve fitting model to analyze the relationship between the total transportation volume and the total import and export volume, conducted elasticity and marginal analysis based on the empirical results, and put forward feasible suggestions for the development of Dongguan’s logistics and import and export trade.
The Empirical Research on the Correlation Between the Internal Control and Earning Management in Private Listed Companies
Authors: Yan Sheng-Nan
Published: September 2021

Under the background of industrial innovation, this paper takes the data of private listed companies from 2011 to 2016 as the sample for empirical analysis, and finds that internal control is an important factor in earnings management. There is a significant negative correlation between internal control and accrued earnings management and real earnings management. That is to say, having a good and rigorous internal control system can effectively reduce earnings management. Moreover, compared with earnings management of accounting selective activities, internal control has more restrictive effect on earnings management of real activities.
Earnings Management, Enterprise Scale and Enterprise Value—Research Based on Data and Statistical Analysis Tools
Authors: Mengxiao Yang
Published: September 2021

This paper takes China’s A-share listed companies in Shanghai and Shenzhen Stock Exchange from 2012 to 2016 as samples to analyze the impact of earnings management on current and subsequent enterprise value. It is found that real earnings management not only affects the current value, but also damages the long-term value of enterprises continuously. Further research finds that the size of the firm has a moderating effect, that is, the larger the size of the firm, the damage effect of real earnings management on the firm value is mitigated.
Research on the Influence of the Characteristics of the Board of Directors of Listed Companies on the Growth of the Company
Authors: Ruirui Gao
Published: September 2021

The board characteristics are an important factor affecting the growth of the company. This paper selects the data of A-share listed companies in the Shanghai and Shenzhen Stock Exchanges during the five-year period from 2014 to 2019, and analyzes whether the board characteristics will affect the growth of the company from a dynamic perspective. The research found that: ① the scale of the board of a listed company has an inverted U-shaped relationship with the company’s growth; ② the proportion of independent directors has a positive correlation with the company’s growth; ③ the director’s salary has a positive correlation with the company’s growth.
Research on Transformation and Upgrading of Sports Industry in Wuhan Economic and Technological Development Zone under Low Carbon Concept
Authors: Zhang Di
Published: September 2021

Sports industry is a sunrise industry and is well recognized as a new green economic growth point. Wuhan, as the capital of Hubei Province, is giving full play to the city spirit of “daring to be the first and pursuing excellence” in the field of sports, and its sports industry is advancing at a rapid pace. As the first national sports industry demonstration base of Wuhan, the Wuhan Economic and Technological Development Zone (WHDZ) has a strong sports foundation and a collection of brand sports events. With great development potential in sports industry, WHDZ should take bold innovation with low carbon concept so as to better achieve the goal of high quality transformation and upgrading of sports industry in this region.
Research on The Effect of Subject Heterogeneity on Innovation Performance in Manufacturing Digital Innovation
Authors: Gao Jing , Zhan Wanfei , Guan Tao , Feng Qiuhong
Published: September 2021

The digital transformation of manufacturing industry accelerates the collaborative innovation of multi-agent value co-creation, which makes the influence of subject heterogeneity on the innovation performance in digital innovation become a focus issue in both theory and practice. This paper builds a conceptual model of subject heterogeneity in digital collaborative innovation influence on the innovation performance from target heterogeneity, knowledge heterogeneity and organization heterogeneity three dimensions, which based on the perspective of the behavior subjects in manufacturing digital innovation of value co-creation. Then we deeply explore the influence mechanism between the heterogeneous cooperative innovation behavior of heterogeneous value subject and the innovation performance in digital innovation. The research results are helpful to realize higher quality digital cooperation among manufacturing enterprises, promote the coordinated development of digital value chain, and improve the digital innovation performance.
Analysis on the mechanism, problems and Countermeasures of rural industry integration in China
Authors: pan Quanfu
Published: September 2021

Since the first document of the Central Committee in 2015 first proposed the integrated development of rural primary, secondary and tertiary industries, relevant departments of the State Council and local governments at all levels have introduced supportive policies, and the integrated development of rural primary, secondary and tertiary industries has thus entered a rapid development track. This article will clarify the related theories of the integrated development of rural primary, secondary and tertiary industries, analyze the main problems existing in the integrated development of rural industries, and put forward corresponding countermeasures and suggestions for the problems.
Study on commuter travel of urban workers——Analysis of coordination between ground bus and rail transit in Beijing
Authors: TianPei Qi , ZhaoQi Peng
Published: September 2021

At present, with the advancement of China’s urbanization construction process, China’s urbanization rate has gradually increased in recent years, and the population in the suburbs and surrounding towns and rural areas continue to pour into large cities, which inevitably leads to a series of social problems in the process of China’s urban economic development. In the process of population gathering in large cities, traffic problems have a great impact on urban workers. With the increase of urban population and the rising stock of private cars, the efficiency of ground transportation continues to decline; the population aggregation in big cities, the poor travel experience of public transport system in the morning and evening rush hours on weekdays, and the long commuting time and distance of workers restrict the long-term development of large cities in China to a certain extent. This paper studies the coordination between ground public transport and rail transit in Beijing with reference to the coordination of the development of ground public transport and rail transit. Finally, based on these problems, this paper puts forward some suggestions for the long-term coordinated development of public transport in Beijing.
Development on Foreign Trade of Beijing’s Cultural Industry
Authors: Tong Dong
Published: September 2021

Since the 19th National Congress of the Communist Party of China, cultural and creative industry has become more and more important in national economic development. Cultural and creative industry plays an important role in promoting economic development, prosperity and rejuvenation in both countries and regions. Beijing is in the key stage of the construction of the national cultural center, and the foreign trade of cultural and creative industry is an important aspect of the construction of the national cultural center. Based on the analysis of the current situation of Beijing’s cultural and creative industry, this paper points out three urgent problems in the foreign trade of Beijing’s cultural and creative industry from the micro and macro aspects. They are small scale, single form, and the pattern has not yet formed. Finally, the paper puts forward suggestions on the foreign trade of Beijing’s cultural and creative industry: expand the international market, promote foreign investment of cultural enterprises, and form a new pattern of factor market and product market of cultural and creative industry.
Executive Compensation Level, Executive Characteristics and Quality of Internal Control
Authors: DuoRu Duo , Guo Mao Cui , Wang Ze Min
Published: September 2021

In the process of transformation of economic momentum, the digital transformation and upgrading of enterprises has become an inevitable trend. As an important human resource of enterprise operation and management, senior executives play an irreplaceable key role in the process of enterprise transformation and upgrading. therefores, A total of 2244 A-share listed companies in China from 2015 to 2019 are selected for panel data analysis to verify the influence of the level of executive compensation, characteristics of senior executives and quality of internal control. The results show that there is a correlation between the level of executive compensation and the quality of internal control, and the characteristics of senior executives have a partial moderating effect between the level of executive compensation and the quality of internal control, but this moderating effect is weak and may be negative.
Exploration of the Lattice Shop Environment in the Post-epidemic Era
Authors: Wang Penghao , Zhang Haoning , Liu Xingxing , Jiang Xun , Ding Xiaoshan
Published: September 2021

In the post epidemic era, mass entrepreneurship and innovation have become an important driving force to promote the domestic economic cycle and the domestic and international double cycle. Lattice shop has the characteristics of novelty, convenience and low threshold, which can better adapt to the new retail formats, and then build an entrepreneurial service platform. Through the analysis of macroeconomic background, taking Qingdao as an example, this paper investigates the market environment through marketing channels, market characteristics and economic scale, sums up the main factors for the construction of lattice shop location, and provides practical suggestions for the construction of lattice shop platform in this region, so as to promote the industrial innovation and development of lattice shop business model in the local market.
Exploring The Development Strategy Of Cultural And Creative Tourism In Guilin: The Case Of East-West Lane
Authors: Yunfei Zang
Published: September 2021

With the development of tourism economy, cultural and creative tourism promotes the transformation of Guilin traditional tourism and also promotes the restructuring of Guilin tourism industry. This paper adopts the literature analysis method to review relevant literature, and through the analysis of development strategies and innovative research on the creative products with ethnic cultural characteristics of Guilin East-West Lane, to realize Guilin cultural and creative tourism as a new energy for the sustainable development and urban regeneration of Guilin.
Epidemiological Investigation Model of Novel Coronavirus Pneumonia Based on Data Mining Technology
Authors: Chen Kai , Yang Bing , Hao Miao , Yang Hong , Qin Meiyuan , Zhang Chengmei
Published: September 2021

With its extraordinary rapidity of transmission, the COVID-19 pandemic demonstrates the vulnerability of a globalized and networked world. The first months of the pandemic were marked by a significant strain on health-care systems. Since the prospect of pandemics has elevated public health concerns, it is critical to revisit this issue. The primary goal of this essay is to employ data mining technologies and methodologies to do investigative analysis on publicly available information. In this article we shared ways and techniques to handle and control this pandemic in the best possible way using data mining techniques and models. Researchers and scientists will be able to use the results of our poll to come up with new approaches to combat the pandemic.
Optimization strategy of operation and maintenance based on econometric model
Authors: Zhang Xuefei , Li Zhiwei , Wang Chengzhi , Tang Xuejun , Yang Sen
Published: September 2021

With the continuous development of power grid, the investment of equipment assets is increasing sharply during the 13th Five Year Plan Period. There is a growing need for equipment maintenance as the equipment ages and varies in different types from transmission to distribution equipment. Equipment is the base element of healthy power grid development. Therefore, it is important to raise the efficiency and quality of equipment status via operation and maintenance. To improve the effectiveness of equipment maintenance, reduce the maintenance cost, improve the safe operation level and power supply reliability of power grid, this paper uses econometric model of correlation analysis to build the correlation between daily overhaul, operation and maintenance and fault frequency and voltage qualification rate, so as to provide optimal decision for the development of operation, inspection and maintenance of power grid company.
Application of computer vision art based on emoticons in the field of animation
Authors: Cao Yang , Wang Yuxin
Published: September 2021

Starting from the overview, this article explains the connotation of computer vision art and computer animation, and discusses the practical application of computer vision art in emoticon animation, in order to reflect the charm of the integration of technology and art, provide some value for the research in related fields.
Application of FTA-PCR technology combined with LIMS system in food safety inspection
Authors: Li Jianxin , Li Jiaxing , Ou Anlang , Li Jianlin , Rong Zhuosi , Ma Yuhao , Yang Jianhui
Published: September 2021

With the increasing awareness of public health in the world, traditional food safety testing technology can no longer meet the needs of increasingly complex food types and product structures. The combination of traditional testing and biotechnology is a new force in strengthening food protection testing technology. This article analyzes the FTA-PCR technology combined with the LIMS system, based on the traditional chemical food safety testing, combined with the effective application of biotechnology in food safety testing, and explained the FTA-PCR technology combined with the LIMS system for food safety testing. In order to provide some help for the better development of my country’s new food safety testing technology.
Initial Characterization and Expression Pattern Analysis of Tobacco (Nicotiana Tabacum) GMP Synthase Gene
Authors: Zhao Meiwei , Yang Lei , Wu Jiacan , Wang Haijuan , Zhao Zhengxiong
Published: September 2021

The complete mRNA sequence of one tobacco (nicotiana tabacum) gene—guanosine monophosphate (GMP)synthase, was amplified using the rapid amplification of cDNA ends methods. The full-length tobacco GMP synthase gene mRNA was 2,127bp containing a 1,617 bp open reading frame, which encodes a protein of 538 amino acids. Sequence analysis revealed that the GMP synthase of tobacco shares high homology with the GMP synthase of wood tobacco(99%), nicotiana attenuata(99%), nicotiana tomentosiformis(99%), potato(92%), Lycopersicon pennellii(92%), lycopersicon esculentum(92%), capsicum annuum(91%), capsicum chinense(91%) and capsicum baccatum(90%). BLAST analysis within the tobacco high throughout genomic sequences database revealed that this gene has 5 introns and 6 exons. Results also showed that tobacco GMP synthase gene has a closer genetic relationship with the GMP synthase gene of wood tobacco. Tissue expression profile analysis revealed that the tobacco GMP synthase gene was highly expressed in leaf, but moderately expressed in root, flower and stem. Our experiment established the foundation for further research on this tobacco gene.
The review of COVID-19 and the current progress in intervention and diagnostics
Authors: Chen Chunyun , Chen Xi , Guo Liwei , Zou Kanghui
Published: September 2021

COVID-19 was first reported in Wuhan city of Hubei Province of China in December 2019, becoming a pandemic declared by the world health organization. This article is a review of the novel coronavirus disease (COVID-19). It typically informs the genome structure of the SARS-CoV-2 and its pathogenic mechanisms, concludes a series of non-pharmaceutical control methods, and focuses on several testing measures. The inventions of the disease treatments remain an important challenge to all medical institutions while a series of medications have been brought to the public.
Formula optimization of Cordyceps Flower beverage based on sensory analysis experiments
Authors: Li Hui-hui , Huang Rong , Li Ming-chen
Published: September 2021

Cordyceps flower is a new resource as a food and drug, which has a broad market prospect. The paper using Cordyceps flower sporocarp as raw material and adopting sensory results as evaluation criteria, through single factor and orthogonal experiments optimize cordyceps flower beverage formula. The results show that Cordyceps powder should be first leached in a water bath at 80℃ for 15 min at a feed-liquid ratio of 1:30. After centrifugation and filtration, cordyceps flower liquid was obtained. Then the liquid should be reconstitute into 30% diluent. Third, adding 0.04% aspartame, 0.06% citric acid and 0.1% sodium carboxyl methyl cellulose (CMC), a tasty and nutritious cordyceps flower beverage was developed ultimately.
A method for detecting IL-6 in serum of patients with uremia
Authors: Bi Qingbo , Yang Shih-Mo
Published: September 2021

As the gold standard of protein detection, enzyme-linked immunosorbent assay (ELISA) is widely used in medical treatment and biology. Here, we report a digital ELISA method that combines fluorescence-coded magnetic beads with micropore arrays to effectively improve the accuracy of the detection. Fluorescence coded magnetic beads were used as solid support of ELISA, which were modified to specifically capture IL-6 in serum, and then combined with galactosidase to form a sandwich structure. These beads are then mixed with a fluorescent substrate and passed into a microfluidic chip. Under the action of gravity, the beads are trapped and isolated by an array of micropores in the chip. Combined with image recognition technology, the fluorescence intensity of micropores containing enzymes will increase rapidly. By mining image information, the IL-6 content in uremia patients can be detected with high precision.
BA-ELISA isolation of cytosolic Salmonella and vacuolar Salmonella
Authors: Liu Suke
Published: September 2021

Salmonella is a pathogenic Gram-negative bacterium and important zoonotic pathogen survive in host cell, which is well known to cause gastrointestinal infections and even death in human through food contamination. Salmonella survives and reproduces within cells in two forms of cytosolic Salmonella and vacuolar Salmonella. However, the current researches on the mechanism of Salmonella infection was mostly based on the total numbers, and there is no clear distinction between cytosolic Salmonella and vacuolar Salmonella. This article combined biotin-streptavidin-amplified enzyme-linked immunosorbent assay(BA-ELISA) and Flat colony counting method to separate and quantify cytosolic Salmonella and vacuolar Salmonella. The results showed that the anti-Salmonella antibody with a dilution ratio of 1:500 can bind ~1700 Salmonella, and the binding rate reached to~70%. In terms of bacterial counts, vacuolar Salmonella dominates in the early stage of Salmonella infection, and cytosolic Salmonella dominates in the later stage, the reproduction rate of vacuolar Salmonella is significantly lower than cytosolic Salmonella during Salmonella infection, the dynamic growth curve of cytosolic Salmonella and vacuolar Salmonella intuitively reflected the proliferation status of the two forms of Salmonella during the entire process of Salmonella infection.
COVID-19: pathogenic mechanism, detection, and treatment
Authors: Bai Xiaoya , Li Chenghao , Li Yueyan , Lin Yujian
Published: September 2021

COVID-19, which broke out in 2019 in China, is caused by SARS-CoV-2. According to the latest WHO real-time statistics, as of 1:19 p.m. BST on April 22, there were 142557268 cumulative new confirmed cases of coronavirus pneumonia and 3033798 cumulative deaths worldwide. Therefore, it is significant to understand the structure and the pathogenic mechanism of SARS-CoV-2, which is helpful to understand the diagnosis and treatment of sars-cov-2. We primarily investigate related sources on Pubmed and related scholar websites. We found some antiviral drugs such as lopinavir, chloroquine, and its derivative hydroxychloroquine, remdesivir, and arbidol have great potential in the treatment of COVID-19. However, some of them have a serious adverse reaction, reminding us to use them with caution.
Characteristics of Rhizosphere Fungal Community in Spring Wheat Under Different Rotation Fallow modes
Authors: Shi Gongfu , Fang Jing , Wei Shuli , Cheng Yuchen , Zhang Xiangqian , An Yu , Lu Zhanyuan , Zhao Xiaoqing
Published: September 2021

Rhizosphere fungi play an important role in agricultural ecosystems. Their activities and interactions greatly affect various ecosystem processes related to nutrient cycling, soil borne diseases and crop health. The aim of this study was to investigate the effects of rotation fallow mode of spring wheat, potato, fallow and spring wheat, rape, fallow on rhizosphere fungi community structure and functional fungi composition of spring wheat. In this paper, high-throughput sequencing and bioinformatics were used to systematically analyze the diversity, composition and abundance of functional fungi in the rhizosphere of spring wheat at flowering stage. The results showed that: compared with WWW, rotation fallow mode could increase the diversity of rhizosphere fungi and eliminate a small number of specific fungi; The dominant phylum of spring wheat rhizosphere fungi were Ascomycota (32.72-47.99%), Basidiomycota (8.39-34.21%) and Mortierellomycota (2.05-18.42%). Rotation fallow mode significantly increased the relative abundance of Mortierellomycota and Chytridiomycota; The relative abundance of Basidiomycota decreased significantly (P<0.05); By increasing the relative abundance of potentially beneficial genera of Mortierella, unidentified_Mortierellales_sp and Atractiella, Reducing the relative abundance of potentially harmful fungi genera of Fusarium, Plectosphaerella and Alternaria to a certain extent kept the soil healthy. Compared with other modes, WFP is most likely to cause rhizosphere fungi community structure to develop in favor of plant health.
Adhesion Strength of Al/Epoxy Resin Interface over a Wide Range of Loading Rates
Authors: Kimoto Yoshikatsu , Kanamori Kohei , Yonezu Akio , Yamada Hiroyuki
Published: September 2021

This study evaluated the interfacial adhesive strength between aluminium alloy and epoxy resin (Al/epoxy resin) over a wide range of strain rates (loading rates). We conducted three types of tests with different loading rate, i.e., a quasi-static tensile test for the range of lower loading rate, a Split Hopkinson Bar (SHB) for the range of middle loading rate, and Laser Shock Adhesion Test (LaSAT) for the range of higher loading rate. LaSAT is a unique test of adhesion evaluation, since laser induced shock wave is employed to lead interfacial fracture. In parallel, finite element method (FEM) is conducted in order to calculate stress distribution at the interface during LaSAT. As a result, it was found that the interface between the aluminium alloy and the epoxy resin interface shows significant loading rate dependency of the adhesion strength and this tendency is very similar to that of bulk epoxy materials.
Plane strain tension fracture at high strain rate
Authors: Adlafi Morwan , Galpin Bertrand , Mahéo Laurent , Roth Christian C. , Mohr Dirk , Grolleau Vincent
Published: September 2021

Under plane stress conditions, most micromechanical and phenomenological models predict a minimum in ductility for plane strain tension stress state. Therefore, the stress state of plane strain tension plays a crucial role in many forming and crash applications and the reliable measurement of the strain to fracture for plane strain tension is particularly crucial when calibrating modern fracture initiation models. Recently, a new experimental technique has been proposed for measuring the strain to fracture for sheet metal after proportional loading under plane strain conditions. The basic configuration of the new setup includes a dihedral punch which applies out-of-plane loading onto a Nakazima-type of discshaped specimen with two symmetric holes and an outer diameter of 60 mm. In the present work, the applicability of the test is extended to high strain rates. High strain rates of about 100/s to 200/s are obtained using a drop weight tower device with an original sensor for load measurements. Quasi static tests are also performed for comparison, keeping the same specimen geometry, image recording parameters and set-up. The effective strains at fracture are compared from quasi-static to high strain rate loading for three different materials, i.e one aluminium alloy and two steels.
Determination of fracture toughness using the compression fracture technique
Authors: Cady Carl M. , Liu Cheng
Published: September 2021

Many engineering materials of importance can be mechanically characterized as brittle or quasi-brittle solids. Examples include many hard polymers, ceramic composites, and low ductility metals. Fracture toughness is the measure of crack extension as a function of applied load and the resistance of the deforming material to the advance of cracking. In this investigation we use digital image correlation (DIC) for observing and studying the process of macroscopic crack initiation and propagation, and applied linear elastic fracture mechanics (LEFM) to determine the fracture toughness of these materials. We will address issues such as loading configuration for stable crack growth, diagnostics for identifying crack initiation and quantifying the extent of crack growth, and scheme for extracting the stress intensity factor at the moving crack tip. The technique described in this report has been applied to many different materials, but for the purpose of illustrating the application of the technique and data processing scheme, we choose the following materials: graphite and beryllium as materials described in this paper. This technique can be used at any rate with the only limitation being the resolution and rate at which images can be captured.
On the dynamic and quasi-static shear strength of SLM AlSi10Mg
Authors: Amir Ben , Kochavi Eytan , Gruntman Shimon , Gale Yuval , Samuha Shmuel , Sadot Oren
Published: September 2021

Additive manufacturing by selective laser melting (AM-SLM) is an advanced manufacturing approach in which a structure is fabricated by successive thin powder layers melted by a focused laser beam. The aerospace and automotive sectors are especially interested in the AMSLM technology that enables quick production of complex and customized structures. AlSi10Mg alloy has been found to be applicable to AM-SLM mainly because good cast-ability, strong weldability and low shrinkage during solidification. While many studies on the quasi-static mechanical properties and the structure of SLM AlSi10Mg were published, there is limited published research focused on the dynamic properties of SLM AlSi10Mg under high rate strains. In addition to that, the shear strength of SLM aluminium alloys is rarely investigated. This study presents an investigation of the AM-SLM AlSi10Mg static and dynamic shear strength and its dependency on build direction. Experiments included quasi-static shear experiments performed according to the protocol of ASTM B565, and dynamic shear tests performed using a split Hopkinson pressure bar (SHPB), coupled to innovative punch assembly that generates pure dynamic shear loads on the sample. The design of this sample holder has been validated numerically and an experimentally. The quasi-static experiments revealed that the static shear strength is independent of build direction. In contrast, the dynamic tests demonstrated that the dynamic shear strength of vertically built samples is higher by almost 11% than the shear strength of samples built horizontally. This last phenomenon explained with a suggested mechanism based onelectron microscope fractography.
Numerical simulation of multi-hit impact on Ceramic/Composite armor
Authors: Jacquet Nicolas , Forquin Pascal
Published: September 2021

The numerical simulation of ballistic multi-hit impact on ceramic/composite armors is very challenging. The damage introduced by the previous hit affects the performance of the armor. In composite backings the damage is often more diffused than for metallic backings. Moreover, different sources of damage can intervene within the composite material. The present work proposes a mesoscopic scale approach to assess these issues. The 2D woven material is modelled with beams elements embedded in volume elements. Each component has its own material constitutive law and its damaging law. This approach allows to better model the damaging of the material, but also to better identify the material parameters from a set of basic experiments.
Mechanical characterization and numerical modeling of TPMS lattice structures subjected to impact loading
Authors: Santiago Rafael , Almahri Sarah , Lee Dong-Wook , Alabdouli Haleimah , Banabila Omar , Ramos Henrique , Alteneiji Mohammed , Guan Zhongwei , Alves Marcilio
Published: September 2021

The advent of Powder Bed Fusion (PBF) techniques allows the additive manufacturing of complex structures, as Triply Periodic Minimal Surfaces (TPMS) lattices, which exhibit promising characteristics for impact applications, such as lightweight and high-energy absorption. Thus, this work aims to develop a numerical model of TPMS structures to investigate the mechanical response of such structures when subjected to impact loadings. To fulfill this task, stainless steel samples made by PBF technique were mechanically characterized at different strain rates using a universal testing machine and Split Hopkinson Pressure Bar. The testing campaign also explored the compressive and tensile material response, with the strain field being monitored by Digital Image Correlation technique. It was noted that the material exhibits a similar elasto-plastic response on both tension and compression and an evident strain rate hardening when the material is loaded from static (0.001 s-1) to dynamic strain rates (4000 s-1). Constitutive parameters were then obtained and implemented in an explicit finite element model developed through Abaqus CAE. Samples of TMPS lattices were manufactured and tested at different loading velocities, which showed that the FE model developed can be used to predict the impact response of TMPS lattices.
On the effect of the microstructure on the dynamic behaviour of Ti-6Al-4V
Authors: Perosanz Sergio , Viscasillas Manuel , Martin Piris Nuria , Hokka Mikko , Barba Daniel
Published: September 2021

Aerospace components in jet engines need to outstand extreme conditions of high-temperatures and loads. Moreover, these components can sometimes undergo dynamic conditions if impact occurs during the flight. It is critical to understand the behaviour of aerospace alloys under these combined extreme conditions of high-temperature and dynamics loads. One of the most extended alloys used in the compressor and fan stages of commercial jet engines is Ti-6Al4V. The dynamic properties of Ti-6Al-4V are strongly dependent on the microstructure state and the temperature conditions. However, these dependencies are yet not fully understood. Moreover, this alloy can present a wide variety of microstructures depending on the component and manufacturing methods. In this work, we compare the response of five typical Ti-6Al-4V microstructures tested under static and dynamic conditions and different temperatures. The macroscopic response of the alloy is rationalised on the basis of its microstructural state using combined microscopy characterisation and computational modelling. To this end, computational plastic models are constructed and validated against experimental observations. In this way, the relationship between the mechanical properties of each microstructure and the temperature and strain rate conditions can be extracted to optimize the material state under specific dynamics in-service conditions.
Numerical prediction of the ballistic performance of hygrothermally aged CFRP laminates using a multi-scale modelling approach
Authors: Thomson D. , Sommer D. E. , Falcó O. , Quino G. , Cui H. , Erice B. , Petrinic N.
Published: September 2021

A multi-scale modelling strategy is proposed to investigate the potential effects of hygrothermal ageing on the ballistic performance of CFRP laminates. At the micro-scale, damage evolution due to cyclic hygrothermal loads is simulated on a representative microstructure using an adapted fatigue damage law. Then, the results of the micro-mechanical analysis are used to measure the predicted transverse crack density and calibrate a meso-scale material model with the effects of micro-scale damage. Finally, a meso-scale impact model is generated with seeded transverse cracks at the predicted crack density and the calibrated material properties from the homogenisation step, which allows for the performance of the laminate to be compared at different stages of hygrothermal ageing damage.
Localized nonlinear waves in a semiconductor with charged dislocations
Authors: Erofeev Vladimir I. , Leonteva Anna V. , Malkhanov Alexey O. , Shekoyan Ashot V.
Published: September 2021

To describe a nonlinear ultrasonic wave in a semiconductor with charged dislocations, an evolution equation is obtained that generalizes the well-known equations of wave dynamics: Burgers and Korteweg de Vries. By the method of truncated decompositions, an exact analytical solution of the evolution equation with a kink profile has been found. The kind of kink (increasing, decreasing) and its polarity depend on the values of the parameters and their signs. An ultrasonic wave in a semiconductor containing numerous charged dislocations is considered. It is assumed that there is a constant electric field that creates an electric current. The situation is similar to the case of the propagation of ultrasonic waves in piezoelectric semiconductors, but in the problem under consideration, instead of the electric field due to the piezoelectric properties of the medium, the electric field of dislocations appears.
An Evaluation on Fracture Toughness in SUS304 at High Strain Rate Considering Process Zone
Authors: Yoshida Shiguma , Iwamoto Takeshi
Published: September 2021

Some research works report the relationships between transformation toughening and process zone. In SUS304, the reduction of transformation toughening at high strain rate is expected from the result of a small punch test. Currently, the process zone in SUS304 is fuzzily defined. Therefore, a consideration of damaging process is necessary in order to understand a fracture mechanism associated with transformation toughening and process zone. In this study, at first, tensile tests of pre-cracked sheet specimens made of SUS304 are conducted by the split Hopkinson pressure bar in order to understand the fracture mechanism phenomenologically at high deformation rate. During the test, a DC potential difference method is introduced to capture onset time of fracture.