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Research on high-Speed Drilling Performances of Austenitic Stainless Steels

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上海交通大学学报 2004年第z2期38卷 83-88页

作者： J.W.Zhong Y.P.Ma F.h.sun M.Chen School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030China School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030China School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030China School of Mechanical Engineering Shanghai Jiaotong University Shanghai200030China

Due to specific properties arising from their structure (high ductility, high toughness,strong tenacious and low heat conductivity), the stainless steels have poor machinability. The drilling of the stainless steels becomes the machining difficulty for their serious work-hardening and abrasion of tools. In this paper, the austenitic stainless steel is used as the work-piece to perform the contrastive experiments with the TiN coated and TiAlN-coated high-speed steel drills. The cutting force, torque, cutting temperature, and the abrasion of drills and tool life are tested and analyzed in the process of high-speed drilling. Experiment results show the effect of drilling speed on cutting force, cutting temperature, and drill wear. TiAlN-coated drills demonstrate better performances in high speed drilling. The research results will be of great benefit in the selection of drills and in the control of tool wear in high speed drilling of stainless steels.

关键词： stainless steel TiN-coating TiAlN-coating drilling

MICROSTRUCTURE AND MEChANICAL PROPERTIES OFP/M TiAl ALLOYS AND ThE TEMPERATURE EFFECT

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Acta Metallurgica Sinica(English Letters) 1998年第6期11卷 417-424页

作者： Z.M.sun h.hashimoto S.Sumi Y.h.Park T.Abe Z.h.Shan Tohoku Natl Industrial Research Inst Sendai Japan

Two intermetallic compounds of Ti-50at.%Al and Ti-48at.%Al-2at.%Cr were prepared with a mechanical alloying and pulse discharge sintering process. The as-sintered material shows a microstructure of equiaxed gamma grain with sub-micron size. heat treatments in Vacuum at different temperatures up to 1573 K were conducted on the sintered materials. The microstructure of the material coarsened considerably after heat treatment at temperatures higher than 1523 K. The mechanical properties of the as-sintered and the heat treated materials were measured at temperatures up to 973 K, with four-point bending tests. Experimental results indicate that the addition of Cr increases the fracture strength of the intermetallic compound at room temperature and at elevated temperatures as well. The bending fracture strength increases with increasing testing temperature up to about 873 K and a decrease following up. Both fracture strength and fracture strain of the material were found to be improved by heat treatment. (Edited author abstract) 10 Refs.

关键词： titanium aluminide mechanical alloying heat treatment mechanical property temperature

Internal Structure Visualization of Flow and Flame by Process Tomography and PLIF Data Fusion

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Journal of Thermal Science 2018年第1期27卷 64-73页

作者： LIU J. LIU Shi sun S. PAN X I.h.I Schlaberg North China Electric Power University 2 Beinong RoadChangping DistrictBeijing 102206China

To address the increasing demands on pollution control and energy saving, the study of low-emission and high-efficiency burners has been emphasized worldwide. Swirl-induced environmental burners(EV-burners), have notable features aligned with these requirements. In this study, an EV burner is investigated by both an ECT system and an Oh-PLIF system. The aim is to detect the structure of a flame and obtain more information about the combustion process in an EV burner. 3D ECT sensitivity maps are generated for the measurement and Oh-PLIF images are acquired in the same combustion zone as for the ECT measurements. The experimental images of a flame by ECT are in good agreement with the Oh radical distribution pictures captured by Oh-PLIF, which provide a mutual verification of the visualization method.

关键词： Tomographic measurement EV burner ECT Oh-PLIF

影像三维重建安全辅助单孔分体内镜治疗L_(5)/S_(1)极外侧腰椎间盘突出症

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中国组织工程研究 2025年第9期29卷 1876-1882页

作者：冯志萌孙宁孙兆忠李岳飞刘昌震李洒滨州医学院附属医院脊柱外科山东省滨州市256603

背景:单孔分体内镜作为一种新型的内镜技术,适用于治疗极外侧腰椎间盘突出症。但目前国内外针对L_(5)/S_(1)这一发病率极低的极外侧腰椎间盘突出症的研究资料甚少,尚无详尽描述单孔分体内镜治疗L_(5)/S_(1)极外侧腰椎间盘突出症的影像... 详细信息

背景:单孔分体内镜作为一种新型的内镜技术,适用于治疗极外侧腰椎间盘突出症。但目前国内外针对L_(5)/S_(1)这一发病率极低的极外侧腰椎间盘突出症的研究资料甚少,尚无详尽描述单孔分体内镜治疗L_(5)/S_(1)极外侧腰椎间盘突出症的影像解剖学资料。目的:通过影像三维重建确定骨性标志点,并以该标志点准确定位L_(5)出口神经根、L_(5)/S_(1)椎间隙及其他结构之间的位置关系,辅助单孔分体内镜经后外侧入路实现对L_(5)出口神经根的减压,治疗L_(5)/S_(1)极外侧腰椎间盘突出症。方法:选择符合纳入标准的29例L_(5)/S_(1)单侧极外侧腰椎间盘突出症患者,其中男12例,女17例;年龄48-74岁。将患者的腰椎CT数据资料导入Mimics 21.0软件中重建腰椎三维模型。测量L_(5)/S_(1)相关参数:①在横突根部下缘与峡部外侧缘的交点(h)所在矢状面上测量:h分别至L_(5)出口神经根上缘、下缘的垂直距离(a1,a2);h分别至L_(5)下终板、S1上终板的垂直距离(b1,b2);h至L_(5)椎弓根下缘的垂直距离(c);②h至L_(5)椎弓根内侧壁所在矢状面的左右水平距离(d);③h至硬脊膜外侧缘所在矢状面的左右水平距离(e);④h至L_(5)下终板最外侧缘所在矢状面的左右水平距离(f);⑤在L_(5)下终板最外侧缘所在矢状面上测量:h所在横断面分别至L_(5)出口神经根上缘、下缘的垂直距离(g1,g2);h所在横断面分别至L_(5)下终板、S1上终板的垂直距离(h1,h2);⑥h至L_(5)出口神经根最后缘所在冠状面的前后水平距离(i);⑦骶骨翼后缘最高点至L_(5)下终板最后缘所在冠状面的前后水平距离(j)。结果与结论:①男女之间各相关测量参数相比差异无显著性意义(P>0.05);②a1,a2,b1,b2,c,d,e,f,h1,h2,g1,g2,i,j患侧与健侧相比差异无显著性意义(P>0.05);③观测发现,a1与c之间相比差异无显著性意义(P>0.05),表明椎弓根下缘即为L_(5)出口神经根上缘,L_(5)出口神经根紧贴椎弓根下缘并经L_(5)椎体后方向前外侧走行,h均位于L_(5)出口神经根上方;④以h作为骨性标志点,无需向上探查,无需磨除峡部,只需向下、向外侧磨除部分骨质显露L_(5)出口神经根与椎间隙,向内侧有足够的安全距离避免损伤硬脊膜来完成侧隐窝、椎间孔区域的探查减压;⑤术者可在h、L_(5)下终板最外侧缘所在的矢状面及L_(5)横突与骶骨翼构成的“矩形区域”内进行操作,越靠近内下方区域(Kambin三角)越安全;⑥提示单孔分体内镜经后外侧入路治疗L_(5)/S_(1)极外侧腰椎间盘突出症,在镜下以h作为骨性标志点定位L_(5)出口神经根及椎间隙,能实现对L_(5)出口神经根的精准、安全、有效减压。

关键词：极外侧腰椎间盘突出症单孔分体内镜影像三维重建骨性标志数字化软件

Pressure-induced ferroelectric and anti-ferroelectric phase transitions in LaN

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Science China(Physics,Mechanics & Astronomy) 2023年第2期66卷 122-130页

作者： Chi Ding Jianan Yuan Beatriz h.Cogollo-Olivo Yunlong Wang Xiaomeng Wang Jian sun National Laboratory of Solid State Microstructures School of Physics and Collaborative Innovation Center of Advanced MicrostructuresNanjingUniversityNanjing 210093China Applied Math Institute University of CartagenaCartagena de Indias 130001Colombia

In this work,we focus on the structural and electronic properties of lanthanum mono-nitride s under high *** on firstprinciples calculations and crystal structure predictions,we identified an anti-ferroelectric orthogonal phase with space group *** is predicted to be thermodynamically stable from 20 to 60 GPa,above which the tetragonal phase without the antiferroelectric distortion will substitute ***,the anti-ferroelectric distortion can be enhancedby reducing the pressure,and a phase transition to a NiAs-type(B8,P63/mmc) structure occurs at about 20 *** calculated double-well potential for La atoms along the c direction in the B8 phase reveals that it should exhibit ferroelectric properties at low *** calculations well confirm their phase transition sequences under high *** properties calculations suggest that all the newly identified phases are semiconductors and the corresponding structural distortions can increase their *** increasing the pressure to 50 GPa,the tetragonal phase undergoes a semiconductor-to-semimetal *** the spin-orbit coupling into account,the semimetal phase becomes a topological insulator with a small ***,given the similarities between the ionic compounds LaN and BaO,we predict that the most stable phase for BaO at about 25 GPa should also be the anti-ferroelectric orthogonal phase instead of the tetragonal phase.

关键词： ferroelectric phase distortion

Thermodynamic Insights of Base Flipping in TNA Duplex: Force Fields, Salt Concentrations, and Free-Energy Simulation Methods

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CCS Chemistry 2021年第2期3卷 1026-1039页

作者： Zhaoxi sun John Z.h.Zhang State Key Laboratory of Precision Spectroscopy School of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062 NYU-ECNU Center for Computational Chemistry at NYU Shanghai Shanghai 200062 Department of Chemistry New York UniversityNYNY 10003

Threofuranosyl nucleic acid(TNA)is an analogue of DNA with a shift in the internucleotide linkages from the wild-type 5’-to-3’direction to 3’-to-2.’This alteration leads to higher chemical stability,less reactive groups,and lower conformational *** observations indicate that these characteristic changes are attributable to a minimal perturbation of the interaction network,but the thermodynamic stability of the duplex remains unaltered in the TNA *** applied the equilibrium and nonequilibrium free-energy simulations employing three popular assisted model building with energy refinement(AMBER)force fields for nucleotides to investigate this mutation-dependent behavior in the base flipping from T(DNA)residue to the T-to-TFT mutation(TNA)*** force fields were performed similarly,as described in the base-paired ***,after exploring the high-energy regions with free-energy simulations,we observed that these three force fields behaved *** reports conclude that the net-neutral and excess-salt simulations provided similar ***,our free-energy simulation indicated that the presence of excess salt affected the thermodynamic *** free-energy barrier along the base-flipping pathway was generally elevated upon the addition of excess salts,but the relative height of the free-energy barriers in DNA and TNA duplexes did not change *** phenomenon emphasizes the importance of adding sufficient salts in the simulation scheme to reproduce the experimental condition.

关键词： free-energy simulation base flipping,TNA AMBER force fields salt concentration

Phylogenetic diversity of planktonic bacteria in the Chukchi Borderland region in summer

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Acta Oceanologica Sinica 2013年第6期32卷 66-74页

作者： ZENG Yinxin YU Yong LI huirong hE Jianfeng LEE Sang h.sun Kun Key Laboratory for Polar Science of State Oceanic Administration Polar Research Institute of China College of Biological Engineering Jimei University Department of Oceanography Pusan National University

Planktonic bacteria are abundant in the Chukchi Borderland region. however, little is known about their di- versity and the roles of various bacteria in the ocean. Seawater samples were collected from two stations K2S and K4S where sea ice was melting obviously. The analysis of water samples with fluorescence in situ hybridization （FISh） showed that DMSP-degrading bacteria accounted for 13% of the total bacteria at the station K2S. No aerobic anoxygenic phototrophic （AAP） bacteria were detected in both samples. The bacterial communities were characterized by two 16S rRNA gene clone libraries. Sequences fell into four major lineages of the domain Bacteria, including Proteobacteria （Alpha, Beta and Gamma subclasses）, Bac- teroidetes, Actinobacteria and Firmicutes. No significant difference was found between the two clone li- braries. SAR11 and Rhodobacteraceae clades of Alphaproteobacteria and Pseudoalteromonas of Gammapro- teobacteria constituted three dominant fractions in the clone libraries. A total of 191 heterotrophic bacterial strains were isolated and 76% showed extracellular proteolytic activity. Phylogenetic analysis reveals that the isolates fell into Gammaproteobacteria, Bacteroidetes, Actinobacteria and Firmicutes. The most common genus in both the bacterial isolates and protease-producing bacteria was Pseudoalteromonas. UniFrac data showed suggestive differences in bacterial communities between the Chukchi Borderland and the northern Bering Sea.

关键词： diversity planktonic bacteria 16S rRNA gene clone library Chukchi Borderland

Current vortices and magnetic fields driven by moving polar twin boundaries in ferroelastic materials

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npj Computational Materials 2020年第1期6卷 454-459页

作者： Guangming Lu Suzhi Li Xiangdong Ding Jun sun Ekhard K.h.Salje State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China Department of Earth Sciences University of CambridgeCambridge CB23EQUK

Ferroelastic twin boundaries often have properties that do not exist in bulk,such as superconductivity,polarity *** and optimizing domain walls can hence functionalize ferroelastic *** atomistic simulations,we report that moving domain walls have magnetic properties even when there is no magnetic element in the *** origin of a robust magnetic signal lies in polar vortex structures induced by moving domain walls,e.g.,near the tips of needle domains and near domain wall *** vortices generate displacement currents,which are the origin of magnetic moments perpendicular to the vortex *** phenomenon is universal for ionic crystals and holds for all ferroelastic domain boundaries containing dipolar moments.

关键词： magnetic moving walls

神经营养因子3经受体切换促进大鼠脊髓损伤后神经功能的恢复

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中国组织工程研究 2025年第11期29卷 2268-2276页

作者：丛岩于健孙志德康大伟承德医学院附属医院急诊科河北省承德市067000

背景:神经营养因子是治疗脊髓损伤的新方法,调控自噬是其发挥作用的机制之一,但具体的信号通路尚不明确。目的:探讨神经营养因子3如何通过P75NTR/Trk C受体切换来调节少突胶质细胞的自噬以及促进脊髓损伤后神经功能恢复的作用,进一步明... 详细信息

背景:神经营养因子是治疗脊髓损伤的新方法,调控自噬是其发挥作用的机制之一,但具体的信号通路尚不明确。目的:探讨神经营养因子3如何通过P75NTR/Trk C受体切换来调节少突胶质细胞的自噬以及促进脊髓损伤后神经功能恢复的作用,进一步明确具体的分子机制。方法:将24只SD大鼠随机分为3组:假手术组、脊髓损伤组和神经营养因子3组,通过大鼠后肢神经功能评分来评估神经营养因子3对脊髓损伤大鼠的治疗效果,采用Western blot检测各组大鼠脊髓组织中神经营养因子3、Olig1、MBP蛋白以及自噬标记蛋白LC3B的表达水平。在细胞实验中,将少突胶质细胞接种在培养皿中,分为糖氧剥夺组、糖氧剥夺+神经营养因子3组、糖氧剥夺+神经营养因子3+P75NTR质粒组、糖氧剥夺+神经营养因子3+Trk C质粒组、糖氧剥夺+3-甲基腺嘌呤(自噬抑制剂)组及糖氧剥夺+雷帕霉素(自噬激活剂)组。光学显微镜观察少突胶质细胞形态变化,TUNEL染色观察细胞凋亡现象,Western blot检测Trk C受体、P75NTR、LC3B表达及PI3K/AKT/m TOR和AMPK/m TOR信号途径的磷酸化状态。结果与结论:(1)动物实验显示,与假手术组相比,脊髓损伤后神经营养因子3的表达显著增加(Ph是损伤早期与中后期的分界点,与糖氧剥夺组相比,糖氧剥夺+神经营养因子3组少突胶质细胞能够更长时间地维持其形态,Trk C受体在早期表达水平较低而中后期显著上调(P<0.05),P75NTR则在早期上调而中后期下调(P<0.05),自噬水平呈现出先升高后降低的趋势(P<0.05);(3)通过对比糖氧剥夺+神经营养因子3组、糖氧剥夺+雷帕霉素组和糖氧剥夺+3-甲基腺嘌呤组的细胞形态和TUNEL染色结果,发现单独促进或抑制自噬对少突胶质细胞的存活均有不利影响,而类似神经营养因子3这样调节自噬的方法则能最大限度地维持细胞存活;(4)神经营养因子3在早期通过P75NTR/AMPK/m TOR信号通路促进自噬,而在后期通过Trk C/PI3K/AKT/m TOR信号通路抑制自噬。根据上述结果,得到如下结论,即神经营养因子3可以通过P75NTR/Trk C受体的切换能够双向调控少突胶质细胞的自噬,从而维持细胞存活,有助于脊髓损伤后大鼠的神经功能恢复。

关键词：神经营养因子3 自噬少突胶质细胞受体切换凋亡脊髓损伤