Electronic Structure and Half-metallicity of the Heusler Alloy Co2ZrGe

Songtao Li,Yang Liu,Zhi Ren,Xiaohong Zhang,Guodong Liu 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.7

The site preference, the electronic structure and the magnetic properties of Co2ZrGe have beenstudied by using first-principles calculations, and the stabilities of the Cu2MnAl-type and theHg2CuTi-type structures have been tested in this respect. The Cu2MnAltype structure is morefavorable than the Hg2CuTitype structure for the Co2ZrGe compound, and the equilibrium latticeparameter of the Cu2MnAltype Co2ZrGe alloy is 6.06 °A. The Co2ZrGe alloy is found to have anenergy gap in the minority spin direction at the Fermi level (EF ) and the majority spin band showsstrongly metallic characteristic. As a result, the Co2ZrGe alloy is predicted to be a half-metalwith 100% spin polarization of the conduction electrons at the EF . The calculated total magneticmoment is 2.00μB per unit cell, which is in line with the Slater-Pauling curve of Mt = Zt −24. TheCo atom-projected spin moment is 1.02μB, which mainly determines the total moment. Simultaneously,the Zr and the Ge atom moments are −0.08μB and 0.04μB, respectively. The Co2ZrGe alloymay be a promising material for application in future spintronics devices.

Natural frequency analysis and experiment for 3SPS+1PS parallel hip joint manipulator based on rigid-flexible coupling theory

Songtao Wang,Gang Cheng,Xihui Chen,Jianhua Yang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.3

For analyzing natural frequency of a 3SPS+1PS parallel hip joint manipulator, a rigid-flexible coupling theory is proposed. 3SPS denotes that the PHJM has three legs and each leg type is SPS. 1PS denotes that the PHJM has one constrained leg and the constrained leg type is PS. The rigid finite element method and flexible finite element method are the base of the rigid-flexible coupling theory. Firstly, the basic element models of the PHJM are established based on the rigid-flexible coupling analysis. Secondly, the elastic dynamic models of the flexible legs are established based on the Lagrange equation and flexible finite method. Finally, the rigid-flexible coupling model of the PHJM is assembled by building the relationship between the rigid and flexible elements. Based on the rigid-flexible model, the natural frequency of the PHJM is analyzed. In addition, the effect parameters of the natural frequency are analyzed. The analysis results of the natural frequency show that the natural frequency is symmetric distribution in the working space, and the minimum value of the 1 st order natural frequency is 2.3 Hz. The operating frequency (1 Hz) is much lower than the 1 st order natural frequency, so the PHJM will not generate resonance and can operate stably. The analysis results of the parameter show that the PHJM has the minimal sensitivity with the effect parameter E and has the maximal sensitivity with the effect parameter H, so the length of the middle leg has the biggest impact on the natural frequency. Natural frequency analysis results have been checked by the hammer test, which verifies the feasibility of the rigid-flexible coupling theory. At the same time, the regression analysis is carried out based on the hammer test results. Using the rigid-flexible coupling theory to solve the natural frequency of the parallel manipulator, the physical meaning is explicit and the modeling process is clear, so the rigid-flexible coupling theory is a universal method.

When to Preempt? Age of Information Minimization under Link Capacity Constraint

Boyu Wang,Songtao Feng,Jing Yang 한국통신학회 2019 Journal of communications and networks Vol.21 No.3

In this paper, we consider a scenario where a source continuouslymonitors an object and sends time-stamped status updatesto a destination through a rate-limited link. We assume updatesarrive randomly at the source according to a Bernoulli process. Due to the link capacity constraint, it takes multiple time slotsfor the source to complete the transmission of an update. Therefore,when a new update arrives at the source during the transmissionof another update, the source needs to decide whether toskip the new arrival or to switch to it, in order to minimize the expectedaverage age of information (AoI) at the destination. We startwith the setting where all updates are of the same size, and provethat within a broadly defined class of online policies, the optimalpolicy should be a renewal policy, and has a sequential switchingproperty. We then show that the optimal decision of the sourcein any time slot has threshold structures, and only depends on theage of the update being transmitted and the AoI at the destination. We then consider the setting where updates are of different sizes,and show that the optimal Markovian policy also has a multiplethresholdstructure. For each of the settings, we explicitly identifythe thresholds by formulating the problem as a Markov DecisionProcess (MDP), and solve it through value iteration. Special structuralproperties of the corresponding optimal policy are utilized toreduce the computational complexity of the value iteration algorithm.

Operational performance evaluation of bridges using autoencoder neural network and clustering

Chunfeng Wan,Songtao Xue,Huachen Jiang,Liyu Xie,Da Fang,Shuai Gao,Kang Yang,YouLiang Ding 국제구조공학회 2024 Smart Structures and Systems, An International Jou Vol.33 No.3

To properly extract the strain components under varying operational conditions is very important in bridge health monitoring. The abnormal sensor readings can be correctly identified and the expected operational performance of the bridge can be better understood if each strain components can be accurately quantified. In this study, strain components under varying load conditions, i.e., temperature variation and live-load variation are evaluated based on field strain measurements collected from a real concrete box-girder bridge. Temperature-induced strain is mainly regarded as the trend variation along with the ambient temperature, thus a smoothing technique based on the wavelet packet decomposition method is proposed to estimate the temperature-induced strain. However, how to effectively extract the vehicle-induced strain is always troublesome because conventional threshold setting-based methods cease to function: if the threshold is set too large, the minor response will be ignored, and if too small, noise will be introduced. Therefore, an autoencoder framework is proposed to evaluate the vehicleinduced strain. After the elimination of temperature and vehicle-induced strain, the left of which, defined as the model error, is used to assess the operational performance of the bridge. As empirical techniques fail to detect the degraded state of the structure, a clustering technique based on Gaussian Mixture Model is employed to identify the damage occurrence and the validity is verified in a simulation study.

Comparative transcriptomic and physiological analyses of contrasting hybrid cultivars ND476 and ZX978 identify important differentially expressed genes and pathways regulating drought stress tolerance in maize

Guo Liu,Tinashe Zenda,Songtao Liu,Xuan Wang,Hongyu Jin,Anyi Dong,Yatong Yang,Huijun Duan 한국유전학회 2020 Genes & Genomics Vol.42 No.8

Background Drought is the major abiotic stress factor that negatively influences growth and yield in cereal grain crops such as maize (Zea mays L.). A multitude of genes and pathways tightly modulate plant growth, development and responses to environmental stresses including drought. Therefore, crop breeding efforts for enhanced drought resistance require improved knowledge of plant drought responses. Objective Here, we sought to elucidate the molecular and physiological mechanisms underpinning maize drought stress tolerance. Methods We therefore applied a 12-day water-deficit stress treatment to maize plants of two contrasting (drought tolerant ND476 and drought sensitive ZX978) hybrid cultivars at the late vegetative (V12) growth stage and performed a large-scale RNA sequencing (RNA-seq) transcriptome analysis of the leaf tissues. Results A comparative analysis of the two genotypes leaf transcriptomes and physiological parameters revealed the key differentially expressed genes (DEGs) and metabolic pathways that respond to drought in a genotype-specific manner. A total of 3114 DEGs were identified, with 21 DEGs being specifically expressed in tolerant genotype ND476 in response to drought stress. Of these, genes involved in secondary metabolites biosynthesis, transcription factor regulation, detoxification and stress defense were highly expressed in ND476. Physiological analysis results substantiated our RNA-seq data, with ND476 exhibiting better cell water retention, higher soluble protein content and guaiacol peroxidase activity, along with low lipid peroxidation extent than the sensitive cultivar ZX978 under drought conditions. Conclusion Our findings enrich the maize genetic resources and enhance our further understanding of the molecular mechanisms regulating drought stress tolerance in maize. Additionally, the DEGs screened in this study may provide a foundational basis for our future targeted cloning studies.

Stem cell property of postmigratory cranial neural crest cells and their utility in alveolar bone regeneration and tooth development.

Chung, Il-Hyuk,Yamaza, Takayoshi,Zhao, Hu,Choung, Pill-Hoon,Shi, Songtao,Chai, Yang AlphaMed Press 2009 Stem cells Vol.27 No.4

<P>The vertebrate neural crest is a multipotent cell population that gives rise to a variety of different cell types. We have discovered that postmigratory cranial neural crest cells (CNCCs) maintain mesenchymal stem cell characteristics and show potential utility for the regeneration of craniofacial structures. We are able to induce the osteogenic differentiation of postmigratory CNCCs, and this differentiation is regulated by bone morphogenetic protein (BMP) and transforming growth factor-beta signaling pathways. After transplantation into a host animal, postmigratory CNCCs form bone matrix. CNCC-formed bones are distinct from bones regenerated by bone marrow mesenchymal stem cells. In addition, CNCCs support tooth germ survival via BMP signaling in our CNCC-tooth germ cotransplantation system. Thus, we conclude that postmigratory CNCCs preserve stem cell features, contribute to craniofacial bone formation, and play a fundamental role in supporting tooth organ development. These findings reveal a novel function for postmigratory CNCCs in organ development, and demonstrate the utility of these CNCCs in regenerating craniofacial structures.</P>

Research on the Construction of Agricultural and Forestry Product Channels for Rural Revitalization

何星星(Xingxing HE),王珂(Ke WANG),糜燕(Yan MI),张松涛(Songtao ZHANG),陶婷婷(Tingting TAO),杨坤颖(Kunying YANG) Korea Institute for Humanities and Social Sciences 2023 Journal of Global Arts Studies (JGAS) Vol.1 No.1

Packaging of Rift Valley fever virus pseudoviruses and establishment of a neutralization assay method

Yuetao Li,Yongkun Zhao,Cuiling Wang,Xuexing Zheng,Hualei Wang,Weiwei Gai,Hongli Jin,Feihu Yan,Boning Qiu,Yuwei Gao,Nan Li,Songtao Yang,Xianzhu Xia 대한수의학회 2018 Journal of Veterinary Science Vol.19 No.2

Rift Valley fever (RVF) is an acute, febrile zoonotic disease that is caused by the RVF virus (RVFV). RVF is mainly prevalent on the ArabianPeninsula, the African continent, and several islands in the Indian Ocean near southeast Africa. RVFV has been classified by the WorldOrganisation for Animal Health (OIE) as a category A pathogen. To avoid biological safety concerns associated with use of the pathogen inRVFV neutralization assays, the present study investigated and established an RVFV pseudovirus-based neutralization assay. This study usedthe human immunodeficiency virus (HIV) lentiviral packaging system and RVFV structural proteins to successfully construct RVFVpseudoviruses. Electron microscopy observation and western blotting indicated that the size, structure, and shape of the packagedpseudoviruses were notably similar to those of HIV lentiviral vectors. Infection inhibition assay results showed that an antibody against RVFVinhibited the infective ability of the RVFV pseudoviruses, and an antibody neutralization assay for RVFV detection was then established. Thisstudy has successfully established a neutralization assay based on RVFV pseudoviruses and demonstrated that this method can be used toeffectively evaluate antibody neutralization.