bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Analysis on the Measurement of the Formation Time of Carbonless Copy Handwriting by “Fading” Gray Value Measurement Method
Authors: Feng Chao
Published: April 2021

Carbon free carbon copy paper is a special writing material, which often appears in many commercial disputes and cases. The handwriting identification of carbon free carbon copy paper has often become one of the key factors in case adjudication. However, the existing handwriting inspection methods of carbon free carbon copy paper are not effective, and cannot analyze the law of the formation time of carbon free carbon copy handwriting. For this reason, this paper proposes an experimental analysis based on the “fading” gray value measurement method to determine the formation time of carbon free copy handwriting. The characteristics of solvents have an important impact on the formation of handwriting. Therefore, this paper analyzes the characteristics of the existing main pen solvents in terms of fading and copying ability. In this paper, according to the characteristics of carbonless copy characters, combined with the gray value measurement method, the calculation method is optimized. The optimized method is more suitable for the determination of the formation time of carbon free copy handwriting, and has the advantage of simplifying the calculation steps. In the specific test experiments, the relationship between extraction rate and time change, handwriting reproducibility and other items are tested. The experimental results show that the extraction rate of carbon free copy handwriting decreases rapidly with the increase of formation time, and gradually tends to be stable. In this paper, the characteristics of the solvents and colorants for pen and their influence on the formation of handwriting are analyzed. It is concluded that the types and use of solvents and colorants have an impact on the formation time of carbon free copy handwriting.
Basic Public Services, Financial Competition and Economic Growth of Urban Agglomeration on Yangtze River Delta Based on Big Data
Authors: Luo Wei , Li Yan
Published: April 2021

Under the background of big data, achieving equalization and digitization of basic public services and narrowing the regional economic gap are the main problems facing regional coordinated development in the new era. Based on the theoretical analysis of economic growth and public services, the article analyzes the internal logic of basic public services, fiscal competition and economic growth in UA-YRD based on the background of big data, establishes an empirical model of public service supply, fiscal competition and economic growth, and conducts verification analysis. The study concluded that the economic growth of UA-YRD is conducive to the improvement of the quantity and quality of public services, especially for the public services of education and health care, while the competition among local governments is negatively correlated with the supply of public services. and put forward targeted suggestions from the perspective of co-construction and sharing of digital public services for people’s livelihood.
RETRACTED: Design of Network Teaching Platform Based on Artificial Intelligence Technology
Authors: Xing Jingyu
Published: April 2021

In recent years, the rapid development of network teaching has played an important role in the popularization of distance education in China. With the development of network technology, compared with the traditional teaching mode, network teaching platform has more and more obvious advantages, and has become one of the important tools of teaching and learning. However, the traditional network teaching platform is lack of intelligence and interactivity, which can be compensated by artificial intelligence technology. Therefore, this paper puts forward the design and research of network teaching platform based on artificial intelligence technology. In this paper, the development of artificial intelligence platform, as well as the application of artificial intelligence platform, can greatly promote the development of artificial intelligence teaching platform. In this paper, according to the shortcomings of the existing network teaching platform, combined with artificial intelligence technology for optimization and improvement, through the optimization algorithm, simplified steps and other operations, further enhance the intelligence of the teaching platform. In order to further understand the application of network teaching platform in the actual teaching process in our country, this paper has carried out relevant investigation and research. The results show that 3.5% of the students who use the network teaching platform have a good use of the network teaching platform, and the results show that 3.5% of the college students use the network teaching platform in a week.
Big Data Configuration Optimization Strategy Analysis of Thermal-Electric Hybrid Energy System Based on Energy Cascade Utilization
Authors: Miao Bo , Liu Chang , Li Hao , Lin Jingyi
Published: April 2021

In this paper, a typical heat-electric hybrid energy system is taken as an object to construct an economic model of demand-side management optimization and regulation, which aims to minimize the main body cost of terminal source system operation. On this basis, the key influencing factors are detailed modeled. Finally, an example is given to verify the validity of the model and observe the impact of changes in key influencing factors on the results of optimization and control. The research results are conducive to further tap China’s electricity demand side resources, improve its scale and reliability of applications, are conducive to the overall coordination of system reliability, cost, energy efficiency and so on.
Computation Offloading Strategy Based on Improved Auction Model in Mobile Edge Computing Network
Authors: Wan Liyong
Published: April 2021

In order to solve the problem of computing power or low energy of users, and to make better use of the idle resources of surrounding mobile devices, the use of D2D direct communication to perform collaborative computing with surrounding mobile devices is an important way to improve resource utilization and reduce local execution energy consumption and delay. To this end, we propose a D2D computing task offloading strategy based on the auction model. Firstly, the requesting device detects the surrounding idle mobile device resources through D2D communication technology, and constructs a communicated topology diagram of the requesting device and the service device. Then, the auction model is used to solve the computing task migration problem of multi-user and multi-service nodes in D2D. At the same time, the offloading problem is converted into an auction model and the task price model is also reasonably defined through comprehensively considering task energy consumption and time delay. The simulation results show that compared with the traditional migration strategy based on communication rate and computing power, the offloading strategy based on the auction model has achieved good results in terms of energy consumption, delay and failure rate.
Research on the Evolution Relationship between Agricultural Carbon Emissions and Economic Growth in Fujian Province Built on the EKC Model
Authors: Peng Qingxia , Zhan Liyu
Published: April 2021

It is vital to explore the relationship between regional agricultural carbon emissions and economic growth for promoting the research of the agricultural Environmental Kuznets Curve (EKC) in China. Based on this, this research first uses the carbon emissions coefficient method to measure Fujian’s agricultural carbon emissions from 2000 to 2016, and uses the EKC model to explore the evolutionary relationship between regional agricultural carbon emissions and economic growth. Research shows that chemical fertilizers are the main cause of agricultural carbon emissions in Fujian. The agricultural carbon footprints and carbon emission intensity in the research area have not yet met the “inverted U-shape” assumed by EKC. Based on this, the author proposes that Fujian should continue to deepen the adjustment of the agricultural supply-side structure and take the road of green and low-carbon agricultural development. Fujian should implement technology reforms and improve the utilization of fertilizers in agricultural production and other emission reduction measures
Teaching Practice and Exploration of Cloud Class Combined With Mind Map Design in Biochemistry Course in Colleges and Universities of Traditional Chinese Medicine in the Internet Era
Authors: Zhou Feng , Guan Yang , Hu Huiming , Deng Yaqiong , Wei Shaofeng
Published: April 2021

Biochemistry is the core course of life science related majors, which expounds the structure, properties, metabolism and function of biological macromolecules. Mastering these basic knowledge is of great significance to students’ follow-up learning and development. Based on the investigation method, pithy formula method and lesson study method, this paper explores how to use cloud class and mind map to carry out the teaching of traditional Chinese medicine biochemistry, stimulate students’ interest in autonomous learning, help students preview, self-study and review, complete the real-time interactive feedback between teachers and students in the mobile environment, so as to better promote the teaching reform of biochemistry.
The Impact of Internet on the Trade-Off between Investment Return and Asset Structure
Authors: Liu Baifang , Sui Liqiu , Xia Jiahui , Wang Tiantian , Cui Yuna , Song Yanrong , Yang Libo
Published: April 2021

The Internet has an important impact on optimizing the asset structure of enterprises. Restricted by internal and external factors, the optimization of enterprise asset structure is the result of multi-party game. Based on factor analysis, this paper constructs the production technology constraint model of asset structure and optimizes it with capital and income as constraints. In this paper, we study the agent constrained optimization model and discuss the possible solutions of asset structure optimization. This paper finds that the asset structure allocation model with production technology constraints is the basic model of asset structure optimization and has anchoring effect.
Influence of Computer Intelligence on Landscape Design
Authors: Zhu Bin
Published: April 2021

In contemporary society, with the continuous development of modern culture, landscape design methods are gradually enriched. With the continuous growth of social economy and science and technology level, people also put forward higher requirements in landscape design to study the impact of computer intelligence era on landscape design, It can effectively improve the quality of intelligent landscape design. Therefore, this paper studies the impact of computer intelligence on landscape design. This paper first analyzes the application of computer intelligent technology in landscape design, and studies the impact of computer intelligence on all aspects of landscape design. In order to further study the impact of computer intelligence on landscape design, we applied computer intelligence to landscape design, designed a contrast experiment, respectively used traditional methods for landscape design and computer intelligence for landscape design, and analyzed the application effect. The results show that the effect of intelligent landscape design is far greater than that of traditional methods. The score of intelligent landscape design in landscape architecture design is 83 points, in landscape waterscape design is 93 points, in landscape visual design is 86 points, in landscape pavement design is 79 points, in landscape construction score is 88 points ◦ It can be seen that computer intelligence has a great impact on landscape design, which greatly promotes the development of landscape design.
Impact of Tourism Big Data on B & B Sharing Economy
Authors: Zhu Bin
Published: April 2021

In recent years, China’s sharing economy continues to maintain a high-speed development trend, and new formats and new models continue to emerge. Among them, the B & B short-term rental industry is also developing rapidly, which is more in line with the characteristics of the sharing economy era. The emergence of B & B has made up for the market gap and met the personalized and emotional needs of modern consumers. Based on this, this paper analyzes the impact of tourism big data on the B & B sharing economy. In this paper, the mathematical statistics method is used to investigate the tourism accommodation data of a tourist attraction in our city. From the online and offline aspects, the public’s satisfaction with the shared B & B in tourist attractions is analyzed. The results show that the evaluation of accommodation conditions and environment of common tourism accommodation and shared B & B are basically the same, and the evaluation score is 85 points. In addition, from the perspective of facilities and equipment, the gap between the two is relatively small, with 86 points for ordinary tourism accommodation and 83 points for shared B & B. In addition, the service quality scores of the two are basically similar, 86 points for ordinary tourism accommodation and 88 points for shared B & B. The obvious difference between the two is the accommodation price. The reasonable score of ordinary tourism accommodation price is 79 points, the reasonable score of shared B & B price is 91 points, and the catering conditions are also different. The score of ordinary tourism accommodation and shared B & B catering conditions is 86 points and 90 points respectively. In addition, there are still many problems in the development of China’s national accommodation industry. Therefore, this paper puts forward a series of suggestions for the development of shared B & B based on Tourism big data to provide reference value for the development of shared B & B in the era of big data.
Advantages of Multimedia Network Teaching in Ice and Snow Sports Education in Higher Vocational Colleges
Authors: Bi Huolong , Gu Zhenwei , Liu Diangang
Published: April 2021

With the continuous development of artificial intelligence technology, more and more fields in China gradually develop with new technology. The education industry is also constantly pursuing innovation, among which more and more colleges and universities gradually use multimedia network teaching. The purpose of this study is to analyze the advantages of multimedia network teaching in ice and snow sports teaching in higher vocational colleges. This study selects the ice and snow sports course teaching of some universities in Heilongjiang Province as the research object, and divides it into different experimental groups through different teaching methods. Finally, it makes statistics on students’ achievements and teaching feedback, and reflects the role and influence of multimedia network teaching combined with the standard of t test. The results show that the popularity rate of online teaching has also increased from 8.5% in 2012 to 42.1% in 2019. And 87.9% of teachers and students support and are satisfied with the content and method of multimedia teaching. It is concluded that the multimedia network teaching discussed in this research has played a good role in the teaching of ice and snow sports, and has high efficiency, which has contributed to the development of smart devices in the education field.
Construction of Computer Network Website for Education in Ideology and Politics in Colleges
Authors: Chen Xianghui
Published: April 2021

The computer network website for education in ideology and politics is the main method and platform for the school to carry out network ideological and political education for students. Through the construction of the website, students can understand the ideological and political content in multiple channels and comprehensively, and strengthen the depth and breadth of the school’s ideological and political education activities. It can also further strengthen the effectiveness of education in ideology and politics in colleges and universities, improve the quality of the teaching staff, and further regulate and guide students’ words and deeds through the Internet. This paper mainly analyzes the construction of computer network website for education in ideology and politics based on the actual situation of colleges and universities.
Construction and Key Technologies of “One-off Dialing Service” Transport Service Supervision System
Authors: Hu Tiejun , Wang Haiyang , Shang Jinping
Published: April 2021

The construction of 12328 telephone is a process of gathering wisdom from multiple sources, focusing on top-level design, and advancing as a whole nationwide. In the process of project construction, combined with the public’s demand for travel services and the improvement of the transport industry’s governance capabilities, the “12328” telephone system was researched from top-level design, technology research and development, system construction, and data application. Moreover, technological breakthroughs have been carried out based on key and difficult areas. Based on the above research, the telephone service resources of all areas of the transport industry have been integrated, and the national transport service supervision telephone ‘12328’ one-off dialing service has been realized, and an efficient, smooth and convenient channel for public sentiment and information service has been formed. The 12328 transport service supervision system with unified standards, reasonable structure, complete functions and efficient operation has been established nationwide. And by reserving interfaces with related industries, promote the interconnection and intercommunication of comprehensive transport service supervision information and the collaborative processing of business.
Application of Fault Prediction and Health Management in Vehicle Control System
Authors: Yao Zhao , Li Hejia , Tu Chao , Wu Hangyu
Published: April 2021

Vehicle control system is a large and complex system with high degree of integration and informationization, which makes fault diagnosis and support more difficult. It puts forward new requirements for fault prediction and maintenance in terms of improving the reliability and efficiency of vehicle control system and reducing the cost of use and maintenance. In order to ensure the stable operation of vehicle control system and give full play to its combat capability, it is necessary to strengthen the monitoring and health assessment of the operation state of vehicle control system, and make appropriate maintenance decisions according to the health state of the system, so as to improve the security level and effectiveness of the vehicle control system.
Research Hotspots and Progress of Specialty Construction in China Based on CiteSpace and SPSS Quantitative Analysis
Authors: Li Manhong , Zhang Wei
Published: April 2021

Specialty is the basic teaching in colleges and universities to highlight the characteristics of education, improve the quality of teaching, optimize the structure of specialty, and enhance the level of the University. Using the visualization tool of knowledge map, we found that: the core network of specialty research in China has not yet formed. At present, the research mainly focuses on the connotation development of specialty construction, the integration of industry and education, the construction of vocational education curriculum and the construction of characteristic specialtys, showing the research characteristics of “three stages and two directions”. We should further encourage undergraduate colleges and universities to attach importance to the theoretical research of specialty construction, promote the research of characteristic specialtys construction under the collaborative background, and better play the leading edge and diversification of scientific research knowledge.
Formulae for Calculating the Resistance Parameters of Irregular Through-silicon Via
Authors: Ju Yanjie
Published: April 2021

The through-silicon via (TSV) is a key technology in the three-dimensional integrated circuit, and the accuracy of its parasitic parameter extraction is the important factor of ensuring accuracy of the integrated circuit simulation. Due to the influence of the production process, the through-silicon via (TSV) is not a cylinder with a smooth surface and regular shape, and with an increase in the frequency and decrease in the size of the TSV, the irregular shape has more and more influence on the parameter extraction of the TSV. To extract the resistance parameters of an irregular TSV more rapidly and accurately, we studied the high surface ratio trapezoid and rough surface TSV and put forward the analytic expressions for calculating the resistance. The two analytic expressions reflect the change rule of resistance parameters along with the size and frequency variation of the TSV. The error of analytic expression was within 5% when compared with the simulation results, which fully satisfies the requirement of accuracy.
A Transfer Learning Based Unmanned Aerial Vehicle MEMS Inertial Sensors Fault Diagnosis Method
Authors: Gao Tong , Sheng Wei , Yin Yanzhao , Du Xuejie
Published: April 2021

In this paper, we propose a novel transfer learning based micro-electromechanical system (MEMS) inertial sensors fault diagnosis method. First, the MEMS inertial sensors fault diagnosis method is formulated to a deep transfer learning problem in which the offline samples are deemed as source domain and the online samples are set to target domain features. Second, the bidirectional long short-term memory and Hilbert-Huang transformation-based feature transfer model is designed to decrease the discrepancy between SD and TD, that performs the transfer operation using intrinsic mode function features. Then we propose a convolutional neuro network-based transfer learning algorithm to further decrease deep features discrepancy and perform the fault classification tasks on TD. According to the experiments, the proposed FD method has achieved excellent fault classification performance and significantly improvement comparing with the state-of-the art methods.
Application of Travel Service Recommendation Algorithm Based on Cloud Computing
Authors: Arongna  , Sulonggaowa
Published: April 2021

In the context of big data, traditional collaborative filtering recommendation algorithms cannot provide users with accurate recommendation services, making the sparsity of user data become an important factor affecting the accuracy of recommendation in the complex social network environment. This paper mainly studies the design and application of travel service recommendation algorithm based on cloud computing. In this paper, the data is processed based on MapReduce parallel computing framework to improve the performance and speed of the algorithm. The Linux-equipped cluster is deployed under the Hadoop framework. The cluster feasibility test is carried out to realize the recommendation function of the algorithm, and the function of the algorithm is realized according to the actual problems. On the Hadoop big data platform, the traditional algorithm was improved and the hadoop-based collaborative filtering recommendation algorithm was implemented to further improve the recommendation rate and accuracy of the traditional recommendation filtering algorithm.
Characteristics and Trends of Medical-Physical Integration Research-Econometric Analysis Based On CNKI Data (1998-2020)
Authors: Zou Wei , Wang Chao , Luo Yiwen
Published: April 2021

This article uses the visualization software CiteSpace to take the 272 medical-to-physical literatures of China Academic Journals Online Publishing Database (CNKI) as the data source. It attempts to construct knowledge about medical-to-physical integration by quantifying the time of publication, authors, institutions, and keywords. Map and analyze it. The study found that the exploration of medical-physical integration in the context of a healthy China is based on the practice of medical-physical integration. In-depth research is a research hotspot. Based on a comprehensive analysis of the knowledge map of medical-physical integration, the future academic circles on the “medical and physical education reform in various fields and colleges, training professionals” and “improving the masses with sports to promote health concepts, building a healthy China” is likely to become a research hotspot on this topic.
RETRACTED: Countermeasures for Promoting the Development of Sports Economy by Physical Education in Colleges and Universities Based on Big Data Analysis
Authors: Li Nan
Published: April 2021

It can be seen from the successful hosting of the 2008 Olympic Games and the upcoming Winter Olympics in China that my country’s sports economy is on the cusp of rapid development. However, my country’s backward physical education in colleges and universities seriously hinders the development of the sports economy. In order to adapt to the sports economy in my country’s new situation, the reform of college sports education is imminent. To this end, this article mainly injects capital into the reform of physical education in colleges and universities, strengthens teachers through economic strength and complements various competitions, so that my country’s sports economy is steadily on the road of rapid development. In this experiment, the sports economic profit of the experimental group that injected college physical education through the economy was as high as 1.7 million yuan, 8.5 times higher than the control group of traditional physical education. This also confirms that the development of the sports economy first needs to inject capital into sports education, so as to increase people’s consumption of sports activities through education, in order to promote the steady development of my country’s sports economy.
A tunable autocorrelator for pulse measurements at IR FEL-oscillator facilities
Authors: Cicek E. , Seidel W. , Ketenoglu B.
Published: April 2021

Radiation characteristics of a Free-Electron Laser (FEL)
such as pulse length, time structure, intensity, bandwidth,
wavelength, power, frequency, etc., which were measured on a
diagnostics table, are thoroughly discussed. In this respect, pulse
length measurements of an Infrared FEL (IR-FEL) beam are evaluated
through an intensity autocorrelator, designed and installed as a
diagnostics tool at the “Helmholtz-Zentrum Dresden-Rossendorf
(HZDR)-Radiation Source ELBE” of Germany. In addition, the
autocorrelator was designed as a unique, cost-effective, and
in-house setup. It operates within the wavelength range of
3–35 microns, using Cadmium-Telluride (CdTe) crystals in the Second
Harmonic Generation (SHG) medium. The intensity autocorrelation
curves were obtained for the FEL beam with the wavelength of
26.2 microns, indicating an FWHM pulse duration ranging between
3.29–8.03 ps with different optical cavity detuning
values. Furthermore, the pulse duration of Ti: sapphire laser beam
is measured between 1–3 ps through the designed autocorrelator at
the ELBE light source. On the other hand, the setup may pave the way
for pulse length measurements of the Turkish infrared FEL-oscillator
facility (TARLA) as well, which is currently under the hardware
installation phase. Finally, it is elaborated in section 3 that the
unique autocorrelator design fully meets all requirements for pulse
length measurements of an infrared FEL source.
Using social media audience data to analyse the drivers of low-carbon diets
Authors: Eker Sibel , Garcia David , Valin Hugo , van Ruijven Bas
Published: April 2021

Low-carbon lifestyles are key to climate change mitigation, biodiversity conservation, and keeping the Earth in a safe operating space. Understanding the global feasibility and drivers of low-carbon lifestyles requires large scale data covering various countries, demographic and socioeconomic groups. In this study, we use the audience segmentation data from Facebook’s advertising platform to analyse the extent and drivers of interest in sustainable lifestyles, plant-based diets in particular, at a global level. We show that formal education level is the most important factor affecting vegetarianism interest, and it creates a sharper difference in low-income countries. Gender is a strong distinguishing factor, followed by national gross domestic product per capita and age. These findings enable upscaling local empirical studies to a global level with confidence for integrated assessments of low-carbon lifestyles. Future studies can expand this analysis of social media audience data to other consumption areas, such as household energy demand, and can also contribute to quantifying the psychosocial drivers of low-carbon lifestyles, such as personal and social norms.
Application of DRASTIC Entropy Weight Model Method in Groundwater Vulnerability Evaluation in Ordos Area
Authors: Wei Wang , Wenxu Wang , Lin Zhu , Rui Cheng , Lishan Meng , Sheming Chen , Futian Liu
Published: April 2021

The northeastern part of the Ordos Basin is the main recharge area of regional groundwater, the groundwater resources are relatively scarce. The main water supply source in the area is shallow groundwater, and there are many industrial and mining enterprises in the district. The potential groundwater pollution risk is high, and the the shallow groundwater vulnerability evaluation in the region is of great significance for groundwater resources protection.The weight of each indicator of the traditional DRASTIC model is fixed and does not change with the regional conditions, which may cause deviations in the evaluation results. This time, based on the DRASTIC model, the entropy weight coefficient method is introduced to determine the index weight, and the DRASTIC entropy weight model is established to obtain a more scientific and close to the actual conditions of the study area, and provide an important reference and basis for the protection of regional groundwater resources.
An engineered neurovascular unit for modeling neuroinflammation
Authors: Seo Suyeong , Choi Chi-Hoon , Yi Kyung Sik , Kim Seung U , Lee Kangwon , Choi Nakwon , Lee Hong Jun , Cha Sang-Hoon , Kim Hong Nam
Published: April 2021

The neurovascular unit (NVU) comprises multiple types of brain cells, including brain endothelial cells, astrocytes, pericytes, neurons, microglia, and oligodendrocytes. Each cell type contributes to the maintenance of the molecular transport barrier and brain tissue homeostasis. Several disorders and diseases of the central nervous system, including neuroinflammation, Alzheimer’s disease, stroke, and multiple sclerosis, have been associated with dysfunction of the NVU. As a result, there has been increased demand for the development of NVU in vitro models. Here, we present a three-dimensional (3D) immortalized human cell-based NVU model generated by organizing the brain microvasculature in a collagen matrix embedded with six different types of cells that comprise the NVU. By surrounding a perfusable brain endothelium with six types of NVU-composing cells, we demonstrated a significant impact of the 3D co-culture on the maturation of barrier function, which is supported by cytokines secreted from NVU-composing cells. Furthermore, NVU-composing cells alleviated the inflammatory responses induced by lipopolysaccharides. Our human cell-based NVU in vitro model could enable elucidation of both physiological and pathological mechanisms in the human brain and evaluation of safety and efficacy in the context of high-content analysis during the process of drug development.
Gradient rhenium doping enabled tunable anisotropic valleytronic material based on monolayer molybdenum disulfide
Authors: Ma Xinli , Zhang Jing , Lai Jiawei , Zhang Mingwen , Zheng Jingchuan , Wu Sen , Hu Xiaodong , Wang Qinsheng , Gan Xuetao , Sun Dong , Liu Jing
Published: April 2021

Two-dimensional molybdenum disulfide (MoS2) possesses premium electrical, optoelectrical and valleytronic properties to develop future nano-electronic and optoelectronic devices. Valleytronic material platform with anisotropic response is highly desired to develop polarization sensitive valleytronic devices. In this work, we acquire monolayer MoS2 with both valley degree of freedom and anisotropy by introducing Re doping during chemical vapor deposition growth. The atomic substitution with Re element induces prominent n-type doping. Electrical tests under both dark and light illumination show that 5 at% Re-doped MoS2 achieves the optimum electrical and optoelectrical performances, corresponding to 27 and 35 times improved carrier mobility and photoresponsivity than pristine MoS2, respectively. Second harmonic generation (SHG) and polarization Raman spectroscopy (PRS) indicate increased anisotropic optical response of Re doped MoS2 as Re concentration increases: maximum anisotropic ratios of 1.6 and 1.7 have been achieved for SHG and PRS measurements at different doping concentrations, respectively. Circularly polarized PL measurement demonstrates that the Re-doped MoS2 preserves valley dependent optical response. Our theoretical calculations show that the anisotropic response is due to the strain induced by the dopants, so that the 2H lattice structure optical helicity dependent valley selection rules are largely preserved. The work opens promising venue toward polarization sensitive valleytronic material platform.
Fatigue property and failure mechanism of TC4 titanium alloy in the HCF and VHCF region considering different forging processes
Authors: Cui Wenbin , Chen Xuan , Cheng Li , Ding Junliang , Wang Changkai , Wang Bohan
Published: April 2021

Based on the self-built three point bending ultrasonic fatigue test system, fatigue behavior of TC4 titanium alloy after different forging processes in high cycle fatigue (HCF) and very high cycle fatigue (VHCF) regimes was discussed in this paper. The experimental results showed that the fatigue S-N curves of TC4 titanium alloy with three different structures presented different characteristics: continuous decline; double platform; linear decline. The fatigue property of TC4 titanium alloy is closely related to the content of primary α phase and β-transformed microstructure. For TC4 titanium alloy, grain refinement and certain volume fraction of the primary α phase contributed to enhancing fatigue property. The fatigue performance of bimodal structure by near β forging was obviously better than two structures by α + β forging in HCF and VHCF regime. It was found that failure mode shifted from the surface at relatively high stress to the subsurface at relatively low stress. For three kinds of structures, crack initiations were observed at the surfaces of specimens in HCF regime. Meanwhile, cracks of the three structures all originated from primary α cleavage planes in the interior. The fatigue life of VHCF is dominated by the crack initiation stage.
Field emission characteristics of a nanotube-fullerene composite: a theoretical study
Authors: Xu Shunfu , Feng Huaiwei , Zhang Yuming , Liu Weihui , Li Chun , Yuan Guang
Published: April 2021

First-principles calculations are used to investigate electronic and field emission characteristics of a nanotube-fullerene composite (a single-walled carbon nanotube (CNT) with a C20 molecule), which indicate that emission currents of the CNT-fullerene composite under external electric fields are roughly four times higher than those of original carbon nanotubes, and its pentagon on the apex is the highest probable positions for electron emission. Moreover, work functions of the CNT-fullerene composite decrease linearly with applied electric fields. The remarkable influence of lithium adsorption on electronic and field emission characteristics of the CNT-fullerene composite is also investigated. After lithium adsorption, the work functions of the CNT-fullerene composite decline evidently, while the emission currents increase polynomially. The emission currents of the adsorption system have been improved by two orders of magnitude (with an order of 10−4 A), and the lithium adatom above on the apex is the most probable position for emission.
Investigation of melt-growth alumina/aluminum titanate composite ceramics prepared by directed energy deposition
Authors: Huang Yunfei , Wu Dongjiang , Zhao Dake , Niu Fangyong , Ma Guangyi
Published: April 2021

Al2O3/Al6Ti2O13 composite ceramics with low thermal expansion properties are promising for the rapid preparation of large-scale and complex components by directed energy deposition-laser based (DED-LB) technology. However, the wider application of DED-LB technology is limited due to the inadequate understanding of process conditions. The shaping quality, microstructure, and mechanical properties of Al2O3/Al6Ti2O13 (6 mol% TiO2) composite ceramics were systematically investigated as a function of energy input in an extensive process window. On this basis, the formation mechanism of solidification defects and the evolution process of microstructure were revealed, and the optimized process parameters were determined. Results show that high energy input improves the fluidity of the molten pool and promotes the uniform distribution and full growth of constituent phases, thus, facilitating the elimination of solidification defects, such as pores and strip gaps. In addition, the microstructure size is strongly dependent on the energy input, increasing when the energy input increases. Moreover, the morphology of the α-Al2O3 phase gradually transforms from cellular into cellular dendrite with increasing energy input due to changing solidification conditions. Under the comprehensive influence of solidification defects and microstructure size, the fracture toughness and flexural strength of Al2O3/Al6Ti2O13 composite ceramics present a parabolic law behavior as the energy input increases. Optimal shaping quality and excellent mechanical properties are achieved at an energy input range of 0.36−0.54 W*min2 g−1 mm−1. Within this process window, the average microhardness, fracture toughness, and flexural strength of Al2O3/Al6Ti2O13 composite ceramics are up to 1640 Hv, 3.87 MPa m1/2, and 227 MPa, respectively. This study provides practical guidance for determining the process parameters of DED-LB of melt growth Al2O3/Al6Ti2O13 composite ceramics.
On the Baum–Connes conjecture for discrete quantum groups with torsion and the quantum Rosenberg conjecture
Authors: Arano Yuki , Skalski Adam
Published: April 2021

We give a decomposition of the equivariant Kasparov category for discrete quantum group with torsion. As an outcome, we show that the crossed product by a discrete quantum group in a certain class preserves the UCT. We then show that quasidiagonality of a reduced

C

∗

\mathrm {C}^{*}

-algebra of a countable discrete quantum group

\mathbbl {\Gamma } implies that

\mathbbl {\Gamma } is amenable, and deduce from the work of Tikuisis, White and Winter, and the results in the first part of the paper, the converse (i.e. the quantum Rosenberg Conjecture) for a large class of countable discrete unimodular quantum groups. We also note that the unimodularity is a necessary condition.
A collar lemma for partially hyperconvex surface group representations
Authors: Beyrer Jonas , Pozzetti Beatrice
Published: April 2021

We show that a collar lemma holds for Anosov representations of fundamental groups of surfaces into

S
L
(
n
,

R

)

SL(n,\mathbb {R})

that satisfy partial hyperconvexity properties inspired from Labourie’s work. This is the case for several open sets of Anosov representations not contained in higher rank Teichmüller spaces, as well as for

Θ
\Theta

-positive representations into

S
O
(
p
,
q
)

SO(p,q)

if

p
≥
4

p\geq 4

. We moreover show that ‘positivity properties’ known for Hitchin representations, such as being positively ratioed and having positive eigenvalue ratios, also hold for partially hyperconvex representations.
Chronic Blockade of NMDAR Subunit 2A in the Hypothalamic Paraventricular Nucleus Alleviates Hypertension Through Suppression of MEK/ERK/CREB Pathway
Authors: Li Ying , Lu Yu-Xin , Chi Hong-Li , Xiao Tong , Chen Yan-Mei , Fu Li-Yan , Zibrila Abdoulaye Issotina , Qi Jie , Li Hong-Bao , Su Qing , Gao Hong-Li , Zhang Yan , Shi Xiao-Lian , Yu Xiao-Jing , Kang Yu-Ming
Published: April 2021

BACKGROUND

N-Methyl-d-aspartate receptor (NMDAR) in the hypothalamic paraventricular nucleus (PVN) plays critical roles in regulating sympathetic outflow. Studies showed that acute application of the antagonists of NMDAR or its subunits would reduce sympathetic nerve discharges. However, little is known about the effect of long-term management of NMDAR in hypertensive animals.

METHODS

PEAQX, the specific antagonist of NMDAR subunit 2A (GluN2A) was injected into both sides of the PVN of two-kidney, one-clip (2K1C) renal hypertensive rats and control (normotensive rats) for 3 weeks.

RESULTS

Three weeks of PEAQX infusion significantly reduced the blood pressure of the 2K1C rats. It managed to resume the balance between excitatory and inhibitory neural transmitters, reduce the level of proinflammatory cytokines and reactive oxygen species in the PVN, and reduce the level of norepinephrine in plasma of the 2K1C rats. PEAQX administration also largely reduced the transcription and translation levels of GluN2A and changed the expression levels of NMDAR subunits 1 and 2B (GluN1 and GluN2B). In addition, NMDAR was known to function through activating the extracellular regulated protein kinases (ERK) or phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathways. In our study, we found that in the PVN of 2K1C rats treated with PEAQX, the phosphorylation levels of mitogen-activated protein kinase kinase (MEK), ERK1/2, and cAMP-response element-binding protein (CREB) significantly reduced, while the phosphorylation level of PI3K did not change significantly.

CONCLUSIONS

Chronic blockade of GluN2A alleviates hypertension through suppression of MEK/ERK/CREB pathway.
Antihypertensive prescribing patterns and hypertension control in females of childbearing age
Authors: White Blaire M , Anderson Sarah L , Marrs Joel C
Published: April 2021

Purpose

The use of angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) to treat hypertension (HTN) during pregnancy presents well-established risks to a developing fetus. A cross-sectional study was conducted to evaluate the current state of antihypertensive prescribing and contraceptive use in females of childbearing age within a large safety-net health system.

Methods

The retrospective cross-sectional study focused on females aged 18-49 years with a documented diagnosis of HTN. The proportion of patients prescribed an ACE inhibitor or ARB and using a documented form of contraception was calculated. Documented forms of contraception included oral contraceptives, intrauterine devices, injections, implants, and surgical intervention.

Results

A total of 4,187 patients were identified from the HTN registry; after application of exclusion criteria 3,045 patients were included in the study population. The mean age was 39 years (range, 18-49 years). The most frequently prescribed classes of antihypertensive medications were ACE inhibitors and ARBs (one or the other was used by 1,146 patients [37.6%]), followed by thiazide diuretics (n = 710, 23.3%) and calcium channel blockers (n = 599, 19.7%). Of the 1,146 patients prescribed an ACE inhibitor or ARB, 553 (48%) were using a documented form of contraception.

Conclusion

Rates of ACE inhibitor or ARB prescribing to females of childbearing age were high despite the teratogenic risks, and fewer than half of patients had documented protection from pregnancy. Provider and patient education and potential creation of best practice alerts in the electronic medical record regarding the risks of using ACE inhibitors and ARBs in females of childbearing age are warranted.
Alpine speciation and morphological innovations: revelations from a species-rich genus in the northern hemisphere
Authors: Zhang Yazhou , Chen Jianguo , Sun Hang
Published: April 2021

A large number of studies have attempted to determine the mechanisms driving plant diversity and distribution on a global scale, but the diverse and endemic alpine herbs found in harsh environments, showing adaptive evolution, require more studies. Here, we selected 466 species from the genus Saussurea, one of the northern hemisphere’s highest-altitude plant genera with high species richness and striking morphological traits, to explore the mechanisms driving speciation and adaptative evolution. We conducted phylogenetic signals analysis and ancestral character estimation to explore the phylogenetic significance of ecological factors. Moreover, we used spatial simultaneous autoregressive (SAR) error models, modified t-tests and partial regression models to quantify the relative effects of ecological factors and morphological diversity upon diversity and endemism of Saussurea. Phylogenetic analyses reveal that geological influences and climate stability exhibit significant phylogenetic signals and that Saussurea originated at a relatively high elevation. Regression models indicate that geological influences and climatic stability significantly affect the diversity and endemism patterns of Saussurea and its morphological innovations. Moreover, morphological innovations in an area show significant contributions to the local diversity and endemism of Saussurea. We conclude that geological influences (mean altitude and topographic heterogeneity), glacial–interglacial climate stability and phylogenetic conservatism have together promoted the speciation and adaptive evolution of the genus Saussurea. In addition, adaptively morphological innovations of alpine species also promote diversification in local regions. Our findings improve the understanding of the distribution pattern of diversity/endemism and adaptive evolution of alpine specie in the whole northern hemisphere.
A randomized clinical trial of an eHealth intervention on anxiety in patients undergoing abdominal aortic aneurysm surgery
Authors: Nilsson O , Stenman M , Letterstål A , Hultgren R
Published: April 2021

Background

The potential benefit of eHealth interventions in patients with abdominal aortic aneurysm (AAA) is uncertain. The primary aim of this study was to investigate the effect of an eHealth intervention on anxiety in patients with AAA undergoing surgery.

Methods

A single-centre randomized clinical trial of patients with AAA scheduled for surgical repair was undertaken. The intervention group received an eHealth tool and psychosocial support besides standard care. The control group received standard care. The analysis of treatment effects was performed as intention-to-treat and per protocol analysis. The primary outcome measure was anxiety mean score (Hospital Anxiety and Depression Scale Anxiety (HADS)-A). Secondary outcomes measures were HADS Depression and short-form 12-item health survey mean scores.

Results

Some 120 participants were randomized. No effect on anxiety mean scores was found in the intention-to-treat analysis (−1.21 versus −0.54, P = 0.330). Among those randomized to the intervention, only 30 of 60 participants used the eHealth tool (application (app) users). The app users were younger and had a higher educational level. A decrease in anxiety mean scores was noted in those who used the app in the per protocol analysis (−2.00 versus −0.54, P = 0.028). The intervention group stated a lower physical-component health-related quality of life (HRQoL) (−4.32 versus −1.16, P = 0.042) but mental-component HRQoL and depressive symptoms were unchanged.

Conclusions

Delivery of an eHealth intervention in this RCT did not result in an improvement in anxiety scores in patients awaiting AAA surgery. Uptake of the eHealth tool was low, although it resulted in lower anxiety scores in those participants who actually used it.

Clinical Trial Registration number

NCT03157973 (http://www.clinicaltrials.gov)