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Segregation of solute atoms in ZrC grain boundaries and their effects on grain boundary strengths

Journal of Materials Science & Technology 2022年第6期101卷 234-241页

作者： Fu-Zhi Dai Yinjie Sun Yixiao Ren Huimin Xiang Yanchun Zhou Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing 100076China

ZrC is a promising candidate for the application in ultra-high temperature regime due to its unique combination of excellent properties,such as high melting point,good chemical inertness and high temperature stability.The rapid decrease of strength at high temperatures,however,is one of the obstacles that impedes its practical services.Strengthening of grain boundaries by solute segregation is believed to be an effective way to improve its high temperature performance.Therefore,the segregation tendency of ten solid solute atoms,including Sc,Ti,V,Cr,Y,Nb,Mo,Hf,Ta,W,in Zr C grain boundaries,and the strengthening/weakening effects on grain boundaries due to segregation are investigated by first-principles calculations.The segregation tendency is found dominated by the size effect,which is confirmed by both a qualitative analysis and a quantitative approach based on support vector regression.It means that big atoms tend to segregate to grain boundary sites with local expansions,while small atoms tend to segregate to grain boundary sites with local compressions.Simulations on stress-strain responses indicate that segregation of small atoms(Ti,V,Cr,Nb,Ta,Mo,W)can usually improve grain boundary strengths by inducing compression strains to grain boundaries,even though there is also an exception.In contrast,segregation of Sc and Y will soften grain boundaries.The results reveal that strengthening of grain boundaries by solute segregation is a valuable avenue to enhance high temperature mechanical properties of ZrC,providing guidelines for further design of ZrC based materials.

关键词： ZrC Grain boundary Segregation Strength First-principles calculation Machine learning

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Grain boundary segregation induced strong UHTCs at elevated temperatures:A universal mechanism from conventional UHTCs to high entropy UHTCs

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Journal of Materials Science & Technology 2022年第28期123卷 26-33页

作者： Fu-Zhi Dai Bo Wen Yinjie Sun Yixiao Ren Huimin Xiang Yanchun Zhou Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing 100076China DP Technology Beijing 100044China

Ultra-high temperature ceramics(UHTCs)exhibit a unique combination of excellent properties,including ultra-high melting point,excellent chemical stability,and good oxidation resistance,which make them promising candidates for aerospace and nuclear applications.However,the degradation of hightemperature strength is one of the main limitations for their ultra-high temperature applications.Thus,searching for mechanisms that can help to develop high-performance UHTCs with good high-temperature mechanical properties is urgently needed.To achieve this goal,grain boundary segregation of a series of carbides,including conventional,medium entropy,and high entropy transition metal carbides,i.e.,Zr_(0.95)W_(0.05)C,TiZrHfC_(3),ZrHfNbTaC_(4),TiZrHfNbTaC_(5),were studied by atomistic simulations with a fitted Deep Potential(DP),and the effects of segregation on grain boundary strength were emphasized.For all the studied carbides,grain boundary segregations are realized,which are dominated by the atomic size effect.In addition,tensile simulations indicate that grain boundaries(GBs)will usually be strengthened due to segregation.Our simulation results reveal that grain boundary segregation may be a universal mechanism in enhancing the high-temperature strength of both conventional UHTCs and medium/high entropy UHTCs,since GBs play a key role in controlling the fracture of UHTCs at elevated temperatures.

关键词： UHTCs High entropy ceramics Grain boundary segregation High-temperature strength Machine learning potential

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WNK3 Interacts with NCC

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Science China(Life Sciences) 2016年第11期59卷 1189-1191页

作者： Dexuan Wang Shufang Pan yixiao Xu Xiaohua Ye Xiaobi ren Qiyi Zeng Pediatric Center of Zhujiang Hospital Southern Medical University Department of Pediatrics The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University

Dear Editor,NCC(Na-Cl cotransporter)is a cotransporter mainly distributed in the distal tubule of the kidney,functioning to reabsorb sodium and chloride ions from the tubular fluid into the cells of the renal distal c... 详细信息

关键词： WNK3 Interacts with NCC Figure

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Depression and stress levels increase risk of liver cancer through epigenetic downregulation of hypocretin

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Genes & Diseases 2022年第4期9卷 1024-1037页

作者： Chunyun Pu Shaorong Tian Sanxiu He Weihong Chen Yuanyuan He Hongyan ren Jing Zhu Jun Tang Xiaolan Huang Ying Xiang yixiao Fu Tingxiu Xiang Key Laboratory of Molecular Oncology and Epigenetics The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016PR China Department of Respiratory and Critical Care Medicine The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016PR China Department of Urinary Surgery The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016PR China Department of Oncology The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016PR China Ph.D Research Center for Medical and Social Development Chongqing Medical UniversityChongqing 400016PR China Department of Psychiatry The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016PR China

Recent studies suggest that Hypocretin (HCRT, Orexin) are involved in stress regulation of depression through the hypothalamic-pituitary-adrenal (HPA) axis. However, the molecular mechanism by which Hypocretin regulate neurobiological responses is unknown. Herein, the effects of chronic stress on the epigenetic modification of HCRT and its association with depression were explored with regard to a potential role in cancer progression. In the study, Sprague Dawley (SD) rats were used to establish an animal model of cancer with depression by administrating n-nitrosodiethylamine (DEN) and chronic unpredictable mild stress (CUMS). RNA-sequencing was used to detect differentially expressed genes in the hippocampus of rats and quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the results of RNA-sequencing. The status of HCRT promoter methylation was assessed by methylation specific polymerase chain reaction. Behavioral tests showed that rats exposed to CUMS had significant depressive-like behaviors. The number of liver tumors and tumor load in depressed rats exposed to CUMS was higher than in SD rats without CUMS. RNA-sequencing revealed that HCRT was one of the most siginificantly downregulated gene in the hippocampus of SD rats with CUMS compared to non-stressed group, which was validated by qRT-PCR. HCRT mRNA expression was downregulated and the promoter for HCRT was hyper-methylated in those with depression. These results identified a critical role for chronic psychological stressors in tumorigenesis and cancer progression, via epigenetic HCRT downregulation. Such epigenetic downregulation may be the molecular basis for the association of cancer with depression.

关键词： Cancer Chronic unpredictability mild stress CpG methylation Depressi on Hypocretin

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Path-Following Control of Autonomous Vehicles Considering Coupling Effects and Multi-source System Uncertainties

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Automotive Innovation 2021年第3期4卷 284-300页

作者： yixiao Liang Yinong Li Yinghong Yu Zhida Zhang Ling Zheng Yue ren College of Mechanical and Vehicle Engineering Chongqing UniversityChongqingChina State Key Laboratory of Mechanical Transmission Chongqing UniversityChongqingChina College of Engineering and Technology Southwest UniversityChongqingChina

Path-following control is one of the key technologies of autonomous vehicles,but the complex coupling effects and system uncertainties of vehicles can degrade their control performance.Accordingly,this study proposes targeted methods to solve different types of coupling in vehicle dynamics.First,the types of coupling are figured out and different handling strategies are proposed for each type,among which the coupling caused by steering angle,unsaturated tire forces,and load transfer can be treated as uncertainties in a unified form,such that the coupling effects can be treated in a decoupling way.Then,robust control methods for both lateral and longitudinal dynamics are proposed to deal with the uncertainties in dynamic and physical parameters.In lateral control,a robust feedback-feedforward scheme is utilized in lateral control to deal with such uncertainties.In longitudinal control,a radial basis function neural network-based adaptive sliding mode controller is introduced to deal with uncertainties and disturbances.In addition,the tire saturation coupling that cannot be handled by controllers is treated by a proposed speed profile.Simulation results based on the CarSim-Simulink joint platform evaluate the effectiveness and robustness of the proposed control method.The results show that compared with a well-designed robust controller,the velocity tracking performance,lateral tracking performance,and heading tracking performance improve by 55.68%,34.26%,and 52.41%,respectively,in the double-lane change maneuver,and increase by 87.79%,30.18%,and 9.68%,respectively,in the ramp maneuver.

关键词： Path-following control Autonomous vehicles System uncertainties Robust control

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A repertoire of intronic lariat RNAs reveals tissue-specific regulation and target mimicry potential in plants

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Science China Life Sciences 2024年第6期67卷 1280-1291页

作者： Yong Zhang Xiaotuo Zhang Qi Tang Lei Li Ting Jiang yixiao Fang Hong Zhang Jixian Zhai Guodong ren Binglian Zheng State Key Laboratory of Genetic Engineering Institute of Plant Biology School of Life Sciences Fudan University Department of Biology School of Life Sciences Southern University of Science and Technology

Lariat RNA is concomitantly produced by excised intron during RNA splicing, which is usually debranched by DBR1, an RNA debranching enzyme. However, increasing evidence showed that some lariat RNA could escape debranching. Little is known about how and why these lariat RNAs could be retained. By comparing the atlas of lariat RNAs between the non-dividing cell(mature pollen) and three actively dividing tissues(young shoot apex, young seeds, and young roots), we identified hundreds to thousands of lariat RNA naturally retained in each tissue, and the incidence of lariat RNA retention is much less in shoot apex while much more in pollen. Many lariat RNAs derived from the same intron or different lariat RNAs from the same pre-m RNA could be retained in one tissue while degraded in the other tissues. By deciphering lariat RNA sequences, we identified an AG-rich(RAAAAVAAAR) motif and a UC-rich(UCUCUYUCUC) motif for pollen-specific and the other three tissues-retained lariat RNAs, respectively. Reconstitution of the pollen-specific AG-rich motif indeed enhanced lariat RNA retention in plants. Biologically, hundreds of lariat RNAs harbored mi RNA binding sites, and dual-luciferase reporter assay showed that these natural lariat RNAs had the potential to protect expression of mi RNA target genes. Collectively, our results uncover that selective retention of lariat RNA is an actively regulatory process, and provide new insights into understanding how lariat RNA metabolism may impact mi RNA activity.

关键词： intron turnover lariat RNA miRNA RNA splicing DBR1

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基于最小模型误差估计的智能汽车路径跟踪控制

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汽车工程 2021年第4期43卷 580-587页

作者：任玥冀杰赵颖梁艺潇郑玲西南大学工程技术学院重庆400715 重庆大学汽车工程学院重庆400044

为提高分布式驱动电动智能汽车在自主循迹过程中关键参数的估计精度并降低模型不确定性对控制系统鲁棒性的影响,本文中提出了一种基于观测器的自适应滑模路径跟踪控制策略。首先,针对难以直接精确测量的车辆纵、侧向速度,建立了5输入3输... 详细信息

为提高分布式驱动电动智能汽车在自主循迹过程中关键参数的估计精度并降低模型不确定性对控制系统鲁棒性的影响,本文中提出了一种基于观测器的自适应滑模路径跟踪控制策略。首先,针对难以直接精确测量的车辆纵、侧向速度,建立了5输入3输出3状态的状态估计系统,并采用最小模型误差准则以降低估计过程轮胎的非线性特性带来的观测模型误差。接着,基于运动学模型,计算出了路径跟踪期望横摆角速度响应,并采用自适应滑模算法实现主动转向控制。考虑线控转向系统的潜在失效风险,引入径向基神经网络对系统不确定性进行在线估计。同时,设计了直接横摆稳定控制器并采用最优转矩分配策略,进一步提高车辆的稳定性。最后,对车辆状态估计和路径跟踪进行了Carsim/Matlab联合仿真,结果表明:基于最小模型误差准则的观测器能取得较可靠的估计结果,路径跟踪控制器能保证车辆具有较好的跟踪精度和鲁棒性。

关键词：路径跟踪最小模型误差自适应滑模控制径向基神经网络

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铸造起重机倾倒钩起重量制定算法

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起重运输机械 2019年第17期 71-77页

作者：任嘉新秦义校太原科技大学机械工程学院

铸造起重机是用来吊运高温熔融液态金属的冶金设备,其浇注倾倒提升机构的合理起重量制定对作业安全性和设备可靠性很重要。通过力学分析,推导铸造起重机在吊运钢水包浇注钢液时倾倒钩起重量的制定方法。利用钢水包内腔尺寸和钢液高度... 详细信息

铸造起重机是用来吊运高温熔融液态金属的冶金设备,其浇注倾倒提升机构的合理起重量制定对作业安全性和设备可靠性很重要。通过力学分析,推导铸造起重机在吊运钢水包浇注钢液时倾倒钩起重量的制定方法。利用钢水包内腔尺寸和钢液高度,建立钢水包倾翻力矩与倾翻角的对应关系,再根据倾翻力矩得出铸造起重机倾倒钩起重量与倾翻角的关系,从而得到铸造起重机倾倒钩起重量的制定算法。通过对铸造起重机倾倒不同倾翻机构的钢水包时的倾翻角、倾翻力矩和倾倒钩起重量的分析比较,得到其一系列关联曲线。研究表明,在钢水包倾倒钢液时,其倾翻力矩及起重机的倾倒钩起重量呈现先增大后减小的规律;而当钢液倾倒完毕继续倾倒钢渣时, 不同倾翻机构的钢水包对应的起重机倾倒钩起重量变化却是不同的。本研究为实现钢液平稳恒流浇注和起重机合理设计提供了基础信息。

关键词：倾倒钩起重量倾翻机构倾翻角

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基于荧光标记双向筛选的拟南芥CRISPR基因编辑突变体库构建

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复旦学报（自然科学版） 2023年第2期62卷 179-188页

作者：柳媛蔡宇晨方宜潇杨林任国栋复旦大学生命科学学院植物科学研究所上海200438

突变体库是研究基因功能的重要工具。拟南芥种质资源库(ABRC)储藏了几乎涵盖所有基因的突变体材料,其中T-DNA插入突变体占绝大多数。然而,当在T-DNA插入突变体中进行遗传转化或与其他转基因报告系统进行杂交时容易引起转基因沉默,阻碍... 详细信息

突变体库是研究基因功能的重要工具。拟南芥种质资源库(ABRC)储藏了几乎涵盖所有基因的突变体材料,其中T-DNA插入突变体占绝大多数。然而,当在T-DNA插入突变体中进行遗传转化或与其他转基因报告系统进行杂交时容易引起转基因沉默,阻碍了相关研究的开展,甚至产生错误结论。甲基磺酸乙酯(Ethyl Methane Sulfonate,EMS)诱变和快中子诱变技术可获得非转基因突变体,但这两种方法均为随机诱变技术,需要通过基因定位来确认突变位点,无法实现基因靶向敲除。CRISPR/Cas9可以对目的基因进行靶向编辑,获得不携带转基因的突变体。拟南芥中尚无利用CRISPR/Cas9进行高通量突变体库构建的报道。本研究共设计900条sgRNAs靶向300个RNA通路相关基因,通过合成sgRNA混池文库、引入DsRed2荧光筛选标记、将DNA条形码和二代测序技术相结合,实现了对转基因阳性苗的高通量鉴定和分型,并对T2代具有发育缺陷的无荧光植株进行负向筛选,成功鉴定到了不含转基因的smd3-b和rlua4突变体。

关键词：拟南芥 CRISPR/Cas9 突变体库荧光标记筛选

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高水分挤压组织化植物蛋白纤维结构形成机制研究进展

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中国油脂 2023年第6期48卷 67-72页

作者：李雪菲相海任嘉嘉姚占斌张艺潇中国农业机械化科学研究院集团有限公司北京100083 中机康元粮油装备(北京)有限公司北京100083 中国人民解放军32381部队北京100072

高水分挤压组织化技术是目前生产具有类似动物肉的纤维结构和口感的组织化植物蛋白的主要加工技术。旨在为未来新型植物性肉类类似物的加工和产品设计提供理论参考,从原辅料(植物蛋白、添加剂)、挤压系统参数(水添加量、挤压温度、螺杆... 详细信息

高水分挤压组织化技术是目前生产具有类似动物肉的纤维结构和口感的组织化植物蛋白的主要加工技术。旨在为未来新型植物性肉类类似物的加工和产品设计提供理论参考,从原辅料(植物蛋白、添加剂)、挤压系统参数(水添加量、挤压温度、螺杆转速和喂料速度)、冷却模头三个方面阐述对植物蛋白高水分挤压过程中纤维结构形成的影响机制。蛋白质分子间相互作用力是组织化植物蛋白纤维结构形成的关键,而不同的植物蛋白原料其组织化结构所依赖的蛋白质分子间作用力不同。添加剂可以改变蛋白质等分子内或分子间的作用方式和程度,从而直接影响组织化植物蛋白成品纤维结构的形成。挤压参数主要通过影响蛋白质结构来影响产品质构特性。冷却模头有利于各向异性纤维结构的形成。

关键词：植物蛋白组织化高水分挤压纤维结构水添加量挤压温度冷却模头

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