检索结果-南通市图书馆

Hole surface strengthening mechanism and riveting fatigue life of CFRP/aluminum stacks in robotic rotary ultrasonic drilling

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第10期36卷 471-484页

作者： Song DONG Wenhe LIAO Kan ZHENG Feng XUE lianjun sun School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Carbon fiber reinforced plastic(CFRP)and aluminum stacks are widely used in aviation industry due to light weight and high performance.Millions of rivet holes need to be drilled on body materials,and more than 80%of fatigue cracks occur at the connection holes,so the damage and residual stress of hole surface have crucial effect on the riveting fatigue life of CFRP/aluminum stacks and the flight performance.Recently,robotic rotary ultrasonic drilling(RRUD)technology is a promising method to machine the stacks.However,the hole surface strengthening mechanism in RRUD and the service performance of the riveting joint are not verified.Thus,in this paper,the hole surface strengthening mechanism of RRUD for CFRP/aluminum stacks is investigated,a theoretical residual stress model is established,and the fatigue life experiment of riveted joints is conducted.Firstly,analysis on residual stress in RRUD is carried out with consideration of strengthening force and cutting temperature.Residual stress model is established based on the calculation of elastic stress,plastic stress and stress release.Validation experiment results show that ultrasonic vibration changes residual stress from tensile stress to compressive stress.At the same time,comparative damage analysis of CFRP hole exit and hole surface in robotic conventional drilling(RCD)and RRUD is presented.Finally,fatigue strength experiments of riveted joints are conducted for performance verification.Experimental results indicate that fatigue life of single-hole riveted joints is increased by 68%with ultrasonic vibration,and four-hole riveted joint arranged according to aerospace design standards is increased by more than 86%.

关键词： CFRP/aluminum stacks Drilling damage Residual stress Riveting fatigue life Robotic rotary ultrasonic drilling

Stability analysis of robotic longitudinal-torsional composite ultrasonic milling

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2022年第8期35卷 249-264页

作者： lianjun sun Wenhe LIAO Kan ZHENG Wei TIAN Jinshan LIU Jindan FENG School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China China Academy of Space Technology Beijing 100094China

Currently,industrial robots are considered as an alternative towards traditional machine tools.Especially for the large-scale parts milling,robotic flexibility and low cost make it possess the irreplaceability.However,the milling chatter caused by its weak rigidity hampers robotic application and promotion severely in aviation industry.Rotary ultrasonic milling(RUM)technology with one-dimensional axial vibration has been proven and approved on avoiding robotic chatter.Based on this,the research of project team demonstrates that longitudinal-torsional composite ultrasonic milling(CUM-LT)involving separation characteristic has a greater advantage than RUM in terms of chatter suppression.Thereby,the CUM-LT as a new means is applied to avoid processing vibration of robotic milling system.And its influence mechanism on stability improvement of weak stiffness processing system is clarified.Meanwhile,the approaches to strengthen separation effect are provided innovatively.Moreover,a new analysis method of robotic CUM-LT(RCUM-LT)stability is proposed on the basis of ultrasonic function angles.The simulation and experimental results indicate that compared with robotic RUM(RRUM),stability regions of separated RCUM-LT(SRCUM-LT)and unseparated RCUM-LT(URCUM-LT)are improved by 124.42%and39.20%,respectively.The addition of torsional ultrasonic energy has a wonderful effect on the milling chatter suppression of low stiffness robots.

关键词： Chatter suppression Industrial robots Longitudinal-torsional composite Rotary ultrasonic milling Stability analysis

MALE STERILITY 3 encodes a plant homeodomain-finger protein for male fertility in soybean

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2022年第5期64卷 1076-1086页

作者： Jingjing Hou Weiwei Fan Ruirui Ma Bing Li Zhihui Yuan Wenxuan Huang Yueying Wu Quan Hu Chunjing Lin Xingqi Zhao Bao Peng Limei Zhao Chunbao Zhang lianjun sun State Key Laboratory of Agrobiotechnology Beijing Key Laboratory for Crop Genetic Improvementand College of Agronomy and BiotechnologyChina Agricultural UniversityBeijing 100193China Soybean Research Institute the National Engineering Research Center for SoybeanJilin Academy of Agricultural SciencesChangchun 130033China Jiamusi Branch of Heilongjiang Academy of Agricultural Sciences Jiamusi 154007China

Male-sterile plants are used in hybrid breeding to improve yield in soybean(Glycine max(L.)Merr.).Developing the capability to alter fertility under different environmental conditions could broaden germplasm resources and simplify hybrid production.However,molecular mechanisms potentially underlying such a system in soybean were unclear.Here,using positional cloning,we identified a gene,MALE STERILITY 3(MS3),which encodes a nuclear-localized protein containing a plant homeodomain(PHD)-finger domain.A spontaneous mutation in ms3 causing premature termination of MS3 translation and partial loss of the PHD-finger.Transgenetic analysis indicated that MS3 knockout resulted in nonfunctional pollen and no selfpollinated pods,and RNA-seq analysis revealed that MS3 affects the expression of genes associated with carbohydrate metabolism.Strikingly,the fertility of mutant ms3 can restore under longd conditions.The mutant could thus be used to create a new,more stable photoperiod-sensitive genic male sterility line for two-line hybrid seed production,with significant impact on hybrid breeding and production.

关键词： fertility restoration male sterililty PHD-finger photoperiod soybean

GS6, A Member of the GRAS Gene Family,Negatively Regulates Grain Size in Rice

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2013年第10期55卷 938-949页

作者： lianjun sun Xiaojiao Li Yongcai Fu Zuofeng Zhu Lubin Tan Fengxia Liu Xianyou sun Xuewen sun Chuanqing sun State Key Laboratory of Plant Physiology and Biochemistry National Center for Evaluation of Agricultural Wild Plants (Rice) MOE Key Laboratory of Crop Heterosis and Utilization Key Laboratory of Crop Genetic Improvement Department of Plant Genetics and Breeding China Agricultural University State Key Laboratory of Plant Physiology and Biochemistry National Center for Evaluation of Agricultural Wild Plants(Rice) MOE Key Laboratory of Crop Heterosis and Utilization Key Laboratory of Crop Genetic Improvement Department of Plant Genetics and Breeding China Agricultural University

Grain size is an important yield-related trait in rice. Intensive artificial selection for grain size during domestication is evidenced by the larger grains of most of today＇s cultivars compared with their wild relatives. However, the molecular genetic control of rice grain size is still not well characterized. Here, we report the identification and cloning of Grain Size 6 （GS6）, which plays an important role in reducing grain size in rice. A premature stop at the ＋348 position in the coding sequence （CDS） of GS6 increased grain width and weight significantly. Alignment of the CDS regions of GS6 in 90 rice materials revealed three GS6 alleles. Most japonica varieties （95%） harbor the Type I haplotype, and 62.9% of indica varieties harbor the Type II haplotype. Association analysis revealed that the Type I haplotype tends to increase the width and weight of grains more than either of the Type II or Type III haplotypes. Further investigation of genetic diversity and the evolutionary mechanisms of GS6 showed that the GS6 gene was strongly selected in japonica cultivars. In addition, a ＂ggc＂ repeat region identified in the region that encodes the GRAS domain of GS6 played an important historic role in the domestication of grain size in rice. Knowledge of the function of GS6 might aid efforts to elucidate the molecular mechanisms that control grain development and evolution in rice plants, and could facilitate the genetic improvement of rice yield.

关键词： Domestication GS6 , grain size haplotype Oryza sativa rice.

A reference-grade genome assembly for Astragalus mongholicus and insights into the biosynthesis and high accumulation of triterpenoids and flavonoids in its roots

在线全文

学校读者我要写书评

暂无评论

Plant Communications 2023年第2期4卷 193-213页

作者： Yi Chen Ting Fang He Su Sifei Duan Ruirui Ma Ping Wang Lin Wu Wenbin sun Qichen Hu Meixia Zhao lianjun sun Xuehui Dong College of Agronomy and Biotechnology China Agricultural UniversityBeijing 100193China The Second Clinical Medical College of Guangzhou University of Chinese Medicine Guangdong Provincial Hospital of Traditional Chinese MedicineGuangzhou 510120China Department of Microbiology and Cell Science Institute of Food and Agricultural SciencesUniversity of FloridaGainesvilleFL 32611USA

Astragalus membranaceus var.mongholicus(AMM),a member of the Leguminosae,is one of the most important medicinal plants worldwide.The dried roots of AMM have a wide range of pharmacological effects and are a traditional Chinese medicine.Here,we report the first chromosome-level reference genome of AMM,comprising nine pseudochromosomes with a total size of 1.47 Gb and 27868 protein-encoding genes.Comparative genomic analysis reveals that AMM has not experienced an independent wholegenome duplication(WGD)event after the WGD event shared by the Papilionoideae species.Analysis of long terminal repeat retrotransposons suggests a recent burst of these elements at approximately 0.13 million years ago,which may explain the large size of the AMM genome.Multiple gene families involved in the biosynthesis of triterpenoids and flavonoids were expanded,and our data indicate that tandemduplication has been the main driver for expansion of these families.Among the expanded families,the phenylalanine ammonia-lyase gene family was primarily expressed in the roots of AMM,suggesting their roles in the biosynthesis of phenylpropanoid compounds.The functional versatility of 2,3-oxidosqualene cyclase genes in cluster Ⅲ may play a critical role in the diversification of triterpenoids in AMM.Our findings provide novel insights into triterpenoid and flavonoid biosynthesis and can facilitate future research on the genetics and medical applications of AMM.

关键词： Astragalus membranaceus var.mongholicus genome sequences LTR-RTs triterpenoid flavonoid

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

大豆灰斑病生理小种及抗性遗传研究进展

植物遗传资源学报 2024年第6期25卷 870-881页

作者：肖国政方婷侯晶晶王伟东孙连军中国农业大学农学院北京100193

灰斑病是大豆尾孢菌(Cercospora sojina K. Hara)导致的世界性大豆真菌病害,在大豆主要生产区的流行有增长趋势,给生产带来重大损失。大豆尾孢菌变异迅速,已演化出多个具有致病性差异的生理小种,导致现有品种抗性不能满足生产需求。随... 详细信息

灰斑病是大豆尾孢菌(Cercospora sojina K. Hara)导致的世界性大豆真菌病害,在大豆主要生产区的流行有增长趋势,给生产带来重大损失。大豆尾孢菌变异迅速,已演化出多个具有致病性差异的生理小种,导致现有品种抗性不能满足生产需求。随着分子生物技术的发展,为了获得具有广谱抗性的种质,近年来研究方向从传统的抗病育种转移到对大豆尾孢菌致病机制解析及大豆抗灰斑病基因精细定位上。本文对大豆尾孢菌生理小种的鉴定及其致病性、抗病遗传、抗病育种等方面的国内外研究进展进行了系统综述,并对未来大豆灰斑病的表型精准鉴定、致病机制解析、抗病基因精细定位和抗病育种进行了探讨,为大豆抗灰斑病的进一步研究提供参考。

关键词：大豆灰斑病生理小种抗性遗传抗病育种

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

物联网技术在电力监控系统中的应用研究

中国高新科技 2024年第1期 67-69页

作者：王贤发孙连君顾保国董志远太原卫星发射中心山西太原030045

基于物联网的基本原理及其在电力监控中的应用优势,文章介绍了电力物联网技术在智能化监控系统中的具体应用,涉及安全性、用户管理、设备监控、通信接口等功能,并展望了物联网在电力监控领域的未来应用趋势,包括边缘人工智能、区块链技... 详细信息

基于物联网的基本原理及其在电力监控中的应用优势,文章介绍了电力物联网技术在智能化监控系统中的具体应用,涉及安全性、用户管理、设备监控、通信接口等功能,并展望了物联网在电力监控领域的未来应用趋势,包括边缘人工智能、区块链技术等方面。该研究可为电力系统的智能化监控提供指导,促进电力行业的创新和发展。

关键词：物联网技术电力监控系统智能化监控系统数据监测

Synthesis of ZSM-5 zeolite membranes without organic templates using a varying-concentration technique

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第Z1期25卷 384-389页

作者： CHENG Yue LIAO Runhua LI Jiansheng Wang lianjun sun Xiuyun Jingdezhen Ceramic Institute Jingdezhen 333001 China Jingdezhen Ceramic Institute Jingdezhen 333001 China Department of Environmental Science & Engineering Nanjing University of Science and Technology Nanjing 210094 China Department of Environmental Science & Engineering Nanjing University of Science and Technology Nanjing 210094 China Department of Environmental Science & Engineering Nanjing University of Science and Technology Nanjing 210094 China

Template-free nanosized ZSM-5 seeds with an average size of 15 nm were prepared from a synthesis solution with the composition 12Na2O∶100SiO2∶2Al2O3∶2500H2O. By the use of these seeds, thin ZSM-5 zeolite membranes were prepared on the outer surface of a porous α-alumina tube with a pore size of 2 μm in a gel system by varying-concentration synthesis with organic-free template. The first composition synthesis sol-gel was the same as seeds of molar composition and the second one was 12Na2O∶100SiO2∶2Al2O3∶5000H2O at 180 ℃ for 10 h, respectively. XRD shows that the film consists of well-crystallized ZSM-5 zeolite. SEM investigation indicats that the zeolite films on the supports are defect free and the film thickness is approximately 8 μm. The permeances for H2, N2, CH4 and CO2 are 8.94×10-7, 3.27×10-7, 3.9×10-7, 3.14×10-7 and 0.874×10-7 mol·m2·s-1·Pa-1, respectively. The ideal selectivity of membrane at room temperature for H2/CO2, H2/N2, H2/CH4 are 2.84, 2.73 and 2.29, respectively.

关键词： template-free varying-concentration synthesis ZSM-5 zeolite membrane permeance ideal selectivity

Evaluation of zeolites synthesized from fly ash as potential adsorbents for wastewater containing heavy metals

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2009年第1期21卷 127-136页

作者： WANG Chunfeng,LI Jiansheng,sun Xia,WANG lianjun,sun XiuyunSchool of Chemical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China. School of Chemical Engineering Nanjing University of Science and Technology Nanjing 210094 China

The pure-form zeolites （A and X） were synthesized by applying a two-stage method during hydrothermal treatment of fly ash prepared initial Cu and Zn gel. The difference of adsorption capacity of both synthesized zeolits was assessed using Cu and Zn as target heavy metal ions. It was found that adsorption capacity of zeolite A showed much higher value than that of zeolite X. Thus, attention was focused on investigating the removal performance of heavy metal ions in aqueous solution on zeolite A, comparing with zeolite HS （hydroxyl-solidate） prepared from the residual fly ash （after synthesis of pure-form zeolite A from fly ash） and a commercial grade zeolite A. Batch method was used to study the influential parameters of the adsorption process. The equilibrium data were well fitted by the Langmuir model. The removal mechanism of metal ions followed adsorption and ion exchange processes. Attempts were also made to recover heavy metal ions and regenerate adsorbents.

关键词： fly ash zeolite heavy metal adsorption recovery