检索结果-南通市图书馆

Chinese Chemical Letters 2013年第1期24卷 7-8页

作者： Yan-Ming Shen lin-lin song xu-Hong Qian You-Jun Yang Shanghai Key Laboratory of Chemical Biology School of PharmacyEast China University of Science and Technology

A convenient and scalable synthesis of 1-amino-5-cyanonaphthalene was described.

关键词： 1 5-Disubsituted naphthaleneDye assemblyFluorophore assemblyFluorescent probe

Microstructure and microsegregation of directionally solidified Ti–45Al–8Nb alloy with different solidification rates

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2016年第1期35卷 70-76页

作者： Xiang-Jun xu lin song Xiao-Ou Jin Dong-Dong Han Xin Wang Jun-Pin lin Materials and Chemistry School Zhongyuan University of Technology State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing School of Architecture and Engineering Heilongjiang University

Microstructure and microsegregation of directionally solidified Ti-45Al-8Nb alloy were investigated by scanning electron microscopy（SEM）,transmission electron microscopy（TEM） and electron probe microanalyzer（EPMA）.For the alloy solidified at the solidification rates（v） ranging from 10 to 400 μm·s^（-1）,the microstructure of the mushy zone exhibits a cellular-dendritic structure at lower growth rate（v=10-50 μm·s^（-1）） and a typical dendritic morphology at higher growth rate（v = 100-400 μm·s^（-1））.The relationship between primary dendrite arm spacing（λ_1）and v is λ_1=1.08×10~3v^（-0.35）.Al and Nb elements segregate at interdendritic zone and in the dendritic core,*** solid of mushy zone,a relatively flat concentration profile is observed for the typical dendrite structure,and Nb enriches in B2 phase induced by β→α＋β*** content of B2 phase is hardly affected by *** extent of microsegregation in steady-state zone decreases at a lower growth rate because holding the samples at higher temperature after solidification for a long time can homogenize the solid effectively.

关键词： Nb-containing TiAl alloy Solidification Microstructure Microsegregation

Learning capability of the truncated greedy algorithm

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2016年第5期59卷 49-63页

作者： lin xu Shaobo lin Zongben xu Institute for Information and System Sciences Xi'an Jiaotong University College of Mathematics and Information Science Wenzhou University

Pure greedy algorithm(PGA), orthogonal greedy algorithm(OGA) and relaxed greedy algorithm(RGA) are three widely used greedy type algorithms in both nonlinear approximation and supervised *** this paper, we apply another variant of greedy-type algorithm, called the truncated greedy algorithm(TGA)in the realm of supervised learning and study its learning performance. We rigorously prove that TGA is better than PGA in the sense that TGA possesses the faster learning rate than PGA. Furthermore, in some special cases, we also prove that TGA outperforms OGA and RGA. All these theoretical assertions are verified by both toy simulations and real data experiments.

关键词： supervised learning learning theory generalization capability greedy algorithm truncated greedy algorithm

Gene Expression Profiling Related to Hyphal Growth in a Temperature-Sensitive Mutant of Magnaporthe oryzae

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2013年第12期12卷 2189-2196页

作者： LI xue-song xu Fei WANG Hong-kai lin Fu-cheng State Key Laboratory for Rice Biology Biotechnology InstituteZhejiang University Bioinformatics Lab Institute of Digital AgricultureZhejiang Academy of Agricultural Sciences

The rice blast,caused by fungus Magnaporthe oryzae,is a major constraint to the world food *** growth is the foundation of fungal development and proliferation of *** investigate genes involved in hyphal growth of this fungus,digital gene expression tag profiling was used to compare a previously generated temperature-sensitive mutant which defect at hyphae growth and reduction on pathogenicity,with its related wildtype strain.416 genes were detected as differential expression,178 of which were specifically expressed in Guy-11 but down-regulated expression in the *** classification analysis revealed the phenotype mutation may be mainly caused by a defection in translational and vacuole- related *** results and the protocol used will improve our knowledge on morphogenesis and promote the further study on *** pathogenesis.

关键词： differential expressed gene qRT-PCR gene ontology hyphal growth vacuole

Strain rate sensitivity of tensile properties in high Nb containing TiAl alloys

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2005年第6期12卷 535-539页

作者： Jianfeng Gao Xiangjun xu Junpin lin Xiping song Yanli Wang Guoliang Chen State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

The effect of strain rate on the yield strength of high Nb containing TiAl alloy was studied. The results show that the strain rate sensitivity varies with the test temperature, and the yield strength is not sensitive to the strain rate at room temperature but significantly sensitive to the strain rate at high temperature. An increase of the strain rate or a decrease of the temperature results in an obvious change of fracture mode. It is found that the strain rate sensitivity of this alloy varying with temperature is due to the dislocation climb generated at high temperature.

关键词： TiAl alloys strain rate tensile properties thermal activation

Experimental study on dynamic mechanical property of cemented tailings backfill under SHPB impact loading

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2019年第4期26卷 404-416页

作者： Yu-ye Tan Xin Yu Davide Elmo lin-hui xu Wei-dong song Key Laboratory of High-Efficient Mining and Safety of Metal Mines (Ministry of Education of China) University of Science and Technology Beijing School of Civil and Resources Engineering University of Science and Technology Beijing Norman B.Keevil Institute of Mining Engineering Applied Science SchoolUniversity of British Columbia

Cemented tailings backfill(CTB) have increasingly been used in recent years to improve the stability of mining stopes in deep underground mines. Deep mining processes are often associated with rock bursting and high-speed dynamic loading conditions. Therefore, it is important to investigate the characteristics and dynamic mechanical behavior of CTB. This paper presents the results of dynamic tests on CTB specimens with different cement and solid contents using a split Hopkinson pressure bar(SHPB). The results showed that some CTB specimens exhibited one to two lower stress peaks after reaching dynamic peak stress before they completely failed. The greater the cement-to-tailings ratio is, the more obvious the strain reaction. This property mainly manifested as follows. First,the dynamic peak stress increased with the increase of the cement-to-tailings ratio when the impact velocity was fixed. Second, the dynamic peak stress had a quadratic relationship with the average stress rate. Third, the cement-to-tailings ratio could enhance the increase rate of dynamic peak stress with strain rate. In addition, the dynamic strength enhancement factor K increased with the increase of strain rate, and its value was larger than that of the rock samples. The failure modes of CTB specimens under low-speed impact were tensile failure and X conjugate shear failure, where were nearly the same as those under static uniaxial and triaxial compression. The CTB specimens were crushed and broken under critical strain, a failure mode similar to that of low-strength concrete. The results of the experimental research can improve the understanding of the dynamic mechanical properties of CTB and guide the strength design of deep mining backfills.

关键词： impact loading test cemented tailings backfill dynamic mechanical properties split Hopkinson pressure bar

Strain concentration caused by the closed end contributes to cartridge case failure at the bottom

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2020年第6期16卷 1151-1159页

作者： song Cai Jie Feng Hui xu Kun Liu Zhong-xin Li Zhi-lin Wu School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094JiangsuChina

Ruptures at the bottom of cartridges are a common cause of failure of ammunitions,which directly threatens the safety of weapons and *** on plastic tube theory,this study analyses the radial and axial deformation of a cartridge,considering the radial constraint of the closed end at the bottom of the *** to the influence of the closed end,the bottom of a cartridge does not establish complete contact with the *** to strain concentration in the non-contact area,this area is more amenable to the occurrence of cartridge *** theory predicts the location of the fracture more accurately than the traditional *** maximum axial deformation of a cartridge comprises bending and friction *** maximum strain at the bottom of the cartridge increased by 135%owing to the introduction of bending strain caused by the closed *** strain distribution of a cartridge was measured using digital image correlation technology,and the measured result was consistent with the predicted results of the bending deformation theory and rupture *** effects of wall thickness,radial clearance,friction coefficient,and axial clearance on the axial deformation of the cylinder were *** the wall thickness and reducing radial clearance were found to reduce bending deformation;furthermore,lubrication and reduction in axial clearance reduce frictional deformation,which in turn reduce cartridge rupture.

关键词： Closed end Cartridge case failures Strain concentration Bending deformation

Analysis on damage characteristics and detonation performance of solid rocket engine charge subjected to jet

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2022年第9期18卷 1552-1562页

作者： song-lin Pang Xiong Chen Jin-sheng xu Ge-tu Zhaori Hong-Ying Du School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China The 41st Institute The Sixth AcademyChina Aerospace Science and Industry CorporationHohhot010010China Technology Center Jinxi Industries Group Company LimitedTaiyuan030027China

To further explore the damage characteristics and impact response of the shaped charge to the solid rocket engine(SRE) in storage or transportation, protective armor was designed and the shelled charges model(SCM)/SRE with protective armor impacting by shaped charge tests were conducted. Air overpressures at 5 locations and axial acceleration caused by the explosion were measured, and the experimental results were compared with two air overpressure curves of propellant detonation obtained by related scholars. Afterwards, the finite element software AUTODYN was used to simulate the SCM impacted process and SRE detonation results. The penetration process and the formation cause of damage were analyzed. The detonation performance of TNT, reference propellant, and the propellant used in this experiment was compared. The axial acceleration caused by the explosion was also *** comprehensive comparison, the energy released by the detonation of this propellant is larger, and the HMX or Al particles contained in this propellant are more than the reference propellant, with a TNT equivalent of 1.168-1.196. Finally, advanced protection armor suggestions were proposed based on the theory of woven fabric rubber composite armor(WFRCA).

关键词： Explosion mechanics Shaped charge jet Damage characteristics Detonation performance of propellant

Root-associated(rhizosphere and endosphere) microbiomes of the Miscanthus sinensis and their response to the heavy metal contamination

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2021年第6期33卷 387-398页

作者： Xiaoxu Sun Benru song Rui xu Miaomiao Zhang Pin Gao Hanzhi lin Weimin Sun National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and ManagementInstitute of Eco-environmental and Soil SciencesGuangdong Academy of SciencesGuangzhou 510650China

The plant root-associated microbiomes, including both the rhizosphere and the root endosphere microbial community, are considered as a critical extension of the plant genome. Comparing to the well-studied rhizosphere microbiome, the understanding of the root endophytic microbiome is still in its infancy. Miscanthus sinensis is a pioneering plant that could thrive on metal contaminated lands and holds the potential for phytoremediation applications. Characterizing its root-associated microbiome, especially the root endophytic microbiome, could provide pivotal knowledge for phytoremediation of mine tailings. In the current study, M. sinensis residing in two Pb/Zn tailings and one uncontaminated site were collected. The results demonstrated that the metal contaminant fractions exposed strong impacts on the microbial community structures. Their influences on the microbial community, however, gradually decreases from the bulk soil through the rhizosphere soil and finally to the endosphere, which resulting in distinct root endophytic microbial community structures compared to both the bulk and rhizosphere soil. Diverse members affiliated with the order Rhizobiales was identified as the core microbiome residing in the root of M. sinensis. In addition, enrichment of plant-growth promoting functions within the root endosphere were predicted, suggesting the root endophytes may provide critical services to the host plant. The current study provides new insights into taxonomy and potential functions of the root-associated microbiomes of the pioneer plant, M. sinensis, which may facilitate future phytoremediation practices.

关键词： Tailing Miscanthus sinensis Root endosphere Metal(loid)s contamination

Engineering of Fe d-band center in Fe_(3)O_(4)/CeO_(2)hetero-nanoparticles via orbital coupling for high-efficiency oxygen reduction electrocatalysis

在线全文

学校读者我要写书评

暂无评论

Nano Research 2025年第1期18卷 129-139页

作者： Jiayi Liu Jingwen Yin Yingzi lin Mingxin Pang Huan Pang songtao Zhang lin xu Jun Yang Yawen Tang Jiangsu Key Laboratory of New Power Batteries Jiangsu Collaborative Innovation Center of Biomedical Functional MaterialsSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023Chin a 2 State Key Laboratory of Multiphase Complex Systems Center of MesoscienceInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225009China Testing Center Yangzhou UniversityYangzhou 225009China

The deliberate engineering of the d-band center of metal site represents an effective strategy to boost the intrinsic electrocatalytic performance toward the oxygen reduction reaction(ORR).Herein,following a heterointerfaceinduced orbital coupling rationale,we report a judicious design of an efficient ORR electrocatalyst consisting of Fe_(3)O_(4)/CeO_(2)hetero-nanoparticles in-situ encased into N-doped carbon nanofibers(abbreviated as Fe_(3)O_(4)/CeO_(2)@N-CNFs hereafter).The theoretic calculations uncover that the Fe_(3)O_(4)/CeO_(2)heterointerface-triggered orbital coupling can cause the down shift of the d-band center positions of Fe sites,which leads to the weakened chemisorption of oxygenated groups and lowered energy barrier for the potential-determining step,ultimately dramatically boosting the ORR intrinsic *** a consequence,the well-designed Fe_(3)O_(4)/CeO_(2)@N-CNFs display admirable ORR activity with a half-wave potential of 0.84 V and outstanding structural/electrochemical stability in an alkaline electrolyte,surpassing the commercial Pt/C benchmark and a majority of recently reported Fe_(3)O_(4)-based *** encouragingly,the Fe_(3)O_(4)/CeO_(2)@N-CNFsincorporated Zn-air battery outperforms the Pt/C-assembled counterpart with higher power density,larger energy density,and excellent cycling stability,serving as a competent candidate for ORR-involved renewable energy *** study offers an innovative approach for the rational manipulation of the d-band center and interfacial electron behavior of active sites toward the optimization of electrocatalytic performance.

关键词： hetero-nanoparticles electrospinning interfacial engineering orbital coupling oxygen reduction reaction