Effect of Ultrasonic Treatment on Grain Structure, Eutectic Phase and Mechanical Properties of an Al–6.2 wt% Cu Alloy

Li Zhang,Xiaoqian Li,Ripeng Jiang,Ruiqing Li,Lihua Zhang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.5

The microstructural modification of eutectic phase is a crucial factor for the mechanical properties strengthening of the Al–Cu binary alloy. In this paper, Al–6.2% Cu melts were subjected to ultrasonic treatment from 710 or 660 °C with differentdurations. The microstructural evolutions of primary α-Al grains and α-Al + θ-Al2Cu eutectic phase under ultrasonicationwere investigated based on the nucleation and growth behavior. Results indicated that with the increase of ultrasonic processingtime, the growth of dendritic or petaloid grains were completely suppressed and noticeable refinement to globularmorphology were observed for α-Al grains. Meanwhile, broad lamella-like eutectic structure transformed to debris or evenparticles with continuous ultrasonication. Accordingly, the area fraction, average length and width of coarsening eutecticlamellas were dramatically reduced. In addition, the decrease of coarsening eutectic phase rather than the refinement ofα-Al grains was found to be the main contributor to the enhancement of mechanical properties for Al–6.2% Cu alloy. Themechanisms underlying the transformation of eutectic phase under ultrasonic treatment was also interpreted based on theexperimental results.

Solution to Mixed H2/H∞ Control for Discrete-time Systems with (x,u,v)-dependent Noise

Xiaoqian Li,Wei Wang,Juanjuan Xu,Huanshui Zhang 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.2

In this paper, the stochastic H2=H∞ control problem for linear discrete-time systems with (x;u;v)-dependent noise is studied. By applying the leader-follower stochastic game approach, the disturbance is treatedas the follower and the control input is treated as the leader, respectively. Necessary and sufficient conditions forthe mixed control problem are presented which guarantee the existence and uniqueness of the optimal solution. Byapplying the stochastic maximum principle, the follower first solves a stochastic linear quadratic optimal controlproblem which is given in the form of H∞-norm with the aid of stochastic Riccati equations. Then the leader solves astochastic linear quadratic problem with the aid of forward and backward equations. The main technique is to introducetwo new co-states to capture the future information, the encountered difficulty is to establish a homogeneousrelationship between the new co-states.

Coat colour phenotype of Qingyu pig is associated with polymorphisms of melanocortin receptor 1 gene

Xiaoqian Wu,Zhendong Tan,Linyuan Shen,Qiong Yang,Xiao Cheng,Kun Liao,Lin Bai,Surong Shuai,Mingzhou Li,Xuewei Li,Shunhua Zhang,Li Zhu 아세아·태평양축산학회 2017 Animal Bioscience Vol.30 No.7

Objective: Qingyu pig, a Chinese indigenous pig breed, exhibits two types of coat colour phenotypes, including pure black and white with black spotting respectively. Melanocortin receptor 1 (MC1R) and agouti signaling protein (ASIP) are two widely reported pivotal genes that significantly affect the regulation of coat colour. The objectives of this study were to investigate whether the polymorphisms of these two genes are associated with coat colour and analyze the molecular mechanism of the coat colour separation in Qingyu pig. Methods: We studied the phenotype segregation and used polymerase chain reaction amplification and Sanger sequencing to investigate the polymorphism of MC1R and ASIP in 121 Qingyu pigs, consisting of 115 black and 6 white with black spotted pigs. Results: Coat colour of Qingyu pig is associated with the polymorphisms of MC1R but not ASIP. We only found 2 haplotypes, EQY and Eqy, based on the 13 observed mutations from MC1R gene. Among which, Eqy presented a recessive inheritance mode in black spotted Qingyu pigs. Further analysis revealed a g.462-463CC insertion that caused a frameshift mutation and a premature stop codon, thus changed the first transmembrane domain completely and lost the remaining six transmembrane domains. Altogether, our results strongly support that the variety of Qingyu pig’s coat colour is related to MC1R. Conclusion: Our findings indicated that black coat colour in Qingyu pig was dominant to white with black spotted phenotype and MC1R gene polymorphism was associated with coat colour separation in Qingyu pig.

Identifying natural genotypes of grain number per panicle in rice (Oryza sativa L.) by association mapping

Jianyin Xie,Fengmei Li,Najeeb Ullah Khan,Xiaoyang Zhu,Xueqiang Wang,Zhifang Zhang,Xiaoqian Ma,Yan Zhao,Quan Zhang,Shuyang Zhang,Zhanying Zhang,Jinjie Li,Zichao Li,Hongliang Zhang 한국유전학회 2019 Genes & Genomics Vol.41 No.3

Introduction As one of the main yield components, grain number per panicle (GNP) played critical role in the rice yield improvement. The identification of natural advantageous variations under different situations will promote the sustainable genetic improvement in rice yield. Objectives This study was designed to identify natural genotypes in a rice mini-core collection, to examine the genotypic effects across the indica and japonica genetic background in different environments, and excavating the superior genotypes that had drove the modern genetic improvement. Methods The association mapping of GNP was carried out using a mini-core collection including 154 indica and 119 japonica accessions in seven different environments. Genotypic effects of each genotype for each QTL were calculated and genotype frequency distortion between the commercial rice cultivars and landraces was screened by χ2-test. Results In total, 74 QTLs containing stable and sensitive QTLs in various environments were detected. Within them, 20 positive and 24 negative genotypes in indica, and 24 positive and 16 negative genotypes in japonica were identified. When checking the accumulation of positive genotypes identified in indica across cultivars in each of the two subspecies, it indicated that increased number of positive genotypes identified in indica results in the substantially increased GNP in both indica and japonica across all of the environments, while this trend was not obvious for the positive genotypes identified in japonica especially in short day environments. Moreover, the positive and negative genotype frequency distortion between the landraces and commercial rice cultivars indicated that both positive selection of positive genotypes and negative selection of negative genotypes had driven the genetic improvement on GNP. Conclusion Our findings suggested that the accumulation of positive genotypes and purifying negative genotypes played equivalently important roles in the improvement of rice yield, but the efficient use for some QTLs or genotypes depends on the comprehensive evaluation of their effect under diverse genetic backgrounds and environments.

Dietary Saponins of Sea Cucumber Ameliorate Obesity, Hepatic Steatosis, and Glucose Intolerance in High-Fat Diet–Fed Mice

Xiaoqian Hu,Zhaojie Li,Yong Xue,Jingfeng Wang,Yuming Wang 한국식품영양과학회 2012 Journal of medicinal food Vol.15 No.10

Much attention has been focused on food components that may be beneficial in preventing lifestyle-related diseases. In this study, we investigated the effects of saponins of sea cucumber (SSC) on high-fat diet–induced obesity, insulin resistance, and fatty liver in mice. C57/BL6 mice were fed a high-fat diet, containing 0.03% SSC, or 0.1% SSC for 8 weeks. Both doses of SSC exhibited a weight-loss effect and significantly decreased adipose tissue weight, in both visceral and subcutaneous depots. Furthermore, 0.1% SSC treatment dramatically decreased the hepatic triglyceride and total cholesterol accumulation. Mice administrated with 0.1% SSC had significantly decreased serum glucose and insulin levels, lower homeostatic model assessment for insulin resistance index, and area under the blood glucose curve, suggesting that insulin sensitivity is enhanced by dietary SSC. Dietary SSC also prevented adipokine imbalance, by increasing adiponectin production and decreasing tumor necrosis factor alpha level caused by high-fat diet. Overall, these data demonstrate that SSC could improve certain metabolic parameters associated with obesity.

Does matching relation exist between the length and the tilting angle of terminal implants in the all-on-four protocol? stress distributions by 3D finite element analysis

Li, Xiaomei,Cao, Zhizhong,Qiu, Xiaoqian,Tang, Zhen,Gong, Lulu,Wang, Dalin The Korean Academy of Prosthodonitics 2015 The Journal of Advanced Prosthodontics Vol.7 No.3

PURPOSE. To explore whether there is matching relation between the length and the tilting angle of terminal implants in the All-on-Four protocol by studying the effects of different implant configurations on stress distributions of implant, bone, and framework. MATERIALS AND METHODS. Four implants were employed to support a full-arch fixed prosthesis and five three-dimensional finite element models were established with CT images, based on the length (S and L) and distal tilt angle ($0^{\circ}$, $30^{\circ}$ and $45^{\circ}$) of terminal implants for an edentulous mandible, which named: Tilt0-S, Tilt30-S, Tilt30-L, Tilt45-S and Tilt45-L. An oblique 240 N was loaded at second molar. The von Mises Stresses were analyzed. The implants were consecutively named #1 to #4 from the loading point. RESULTS. 1) Tilt0-S had the greatest stress on the implants, with the other groups exhibiting variable reductions; the four implants of Tilt45-L demonstrated the greatest reduction in stress. 2) Tilt0-S had the greatest stress at bone around #1 implant neck, and Tilt45-L exhibited the least stress, which was a 36.3% reduction compared to Tilt0-S. 3) The greatest stress in the framework was found on the cantilevers distal to #1 implant. Tilt45-S exhibited the least stress. CONCLUSION. Matching different length and tilting angle of the terminal implants led to variable stress reductions on implants, bone and the superstructure. By optimizing implant configuration, the reduction of stress on implants and surrounding bone could be maximized. Under the present condition, Tilt45-L was the preferred configuration. Further clinical testings are required.

Effects of Precipitate Element Addition on Microstructure and Magnetic Properties in Magnetostrictive Fe<SUB>83</SUB>Ga<SUB>17</SUB> alloy

Jiheng Li,Chao Yuan,Wenlan Zhang,Xiaoqian Bao,Xuexu Gao 한국자기학회 2016 Journal of Magnetics Vol.21 No.1

The 〈100〉 oriented Fe83Ga17 alloys with various contents of NbC or B were prepared by directionally solidification method at the growth rate of 720 ㎜·h<SUP>−1</SUP>. With a small amount of precipitates, the columnar grains grew with cellular mode during directional solidification process, while like-dendrite mode of grains growth was observed in the alloys with higher contents of 0.5 at% due to the dragging effect of precipitates on the boundaries. The NbC precipitates disperse both inside grains and along the boundaries of Fe83Ga17 alloys with NbC addition, and the Fe₂B secondary phase particles preferentially distribute along the grain boundaries in B-doped alloys. Precipitates could affect grain growth and improved the 〈100〉 orientation during directional solidification process. Small amount of precipitate element addition slightly increased the magnetostrictive strain, and a high value of 335 ppm under pre-stress of 15 ㎫ was achieved in the alloys with 0.1 at% NbC. Despite the fact that the effect on magnetic induction density of small amount of precipitates could be negligible, the coercivity markedly increased with addition of precipitate element for Fe83Ga17 alloy due to the retarded domain motion resulted by precipitates.

Comparison of Autogenous Tooth Materials and Other Bone Grafts

Zhang Shuxin,Li Xuehan,Qi Yanxin,Ma Xiaoqian,Qiao Shuzhan,Cai HongXin,Zhao Bing Cheng,Jiang Heng Bo,이의석 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.3

Autogenous odontogenic materials are a new, highly biocompatible option for jaw restoration. The inorganic component of autogenous teeth acts as a scaffold to maintain the volume and enable donor cell attachment and proliferation; the organic component contains various growth factors that promote bone reconstruction and repair. The composition of dentin is similar to that of bone, which can be a rationale for promoting bone reconstruction. Recent advances have been made in the field of autogenous odontogenic materials, and studies have confirmed their safety and feasibility after successful clinical application. Autogenous odontogenic materials have unique characteristics compared with other bone-repair materials, such as the conventional autogenous, allogeneic, xenogeneic, and alloplastic bone substitutes. To encourage further research into odontogenic bone grafts, we compared the composition, osteogenesis, and development of autogenous odontogenic materials with those of other bone grafts. In conclusion, odontogenic bone grafts should be classified as a novel bone substitute.

A Bayesian Network Approach to Launch Vehicle Software Failure Prediction

Tinggui Yan,Xiaoqian Chen,Shipeng Li,Li Ma,Jian Bai,Zhifang Yang 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.11

Launch Vehicle software has played an important role in Launch Vehicle system. However, the reliability assessment of Launch Vehicle software is still a hard problem due to the complexity of Launch Vehicle software. Failure prediction can be an effective approach of Launch Vehicle reliability evaluation, whereas failure prediction of software has not yet been fully explored. In this paper, a Markov Bayesian Network model for Launch Vehicle software failure prediction (MBNG) is proposed. In MBNG, unique features of Launch Vehicle software is considered as an important part in the modeling process, which improves the effectiveness of this novel model. Experiments are conducted to verify the effectiveness of MBNG model and compare its performance with classic models.

基于课程教学视角的大学生科研创新能力提升探究 ——以全英文研究方法课程为例

李赪(Cheng Li),董晓骞(Xiaoqian Dong) YIXIN 출판사 2023 教育教学研究论丛 Vol.1 No.4

作为中外合作办学专业大学生从事科学研究的导入性基础课程,全英文研究方法对提升大学生科研创新能力具有重要意义,但实际教学过程中面临着语言水平不齐、教学内容难度大、实操训练难操作等问题。本文以该课程的教研改革为例,通过优化教学目标、重构教学内容、整合教学手段、创新教学活动、再建教学过程等措施提高课程教学质量,提升学生科研创新能力,并期望能为相关教学改革和优化科研创新能力课程体系提供方法参考。 As an introductory basic course for college students in Chinese-foreign cooperative programs to engage in scientific research, Research Methodology in English is of great significance for improving their scientific research and innovation ability. However, in the actual teaching process, it faces many problems such as uneven language level, difficult teaching content and difficult operation in practical training. Taking the teaching and research reform of this course as an example, this paper aims to improve the teaching quality and enhance students’ scientific research and innovation ability by optimizing teaching objectives, reconstructing teaching content, integrating teaching means, innovating teaching activities, and rebuilding teaching process, and hopes to provide reference for related teaching reform and optimization of the curriculum system of scientific research and innovation ability.