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“不属”注释质疑
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作者 周伟明 《中学语文(教师版)》 2000年第11期35-35,共1页
《核舟记》:'佛印绝类弥勒,袒胸露乳,矫首昂视,神情与苏、黄不属。'文中对'不属'二字的注释是'〔不属(zhǔ)〕不相关连。'意即佛印的神情和苏轼、黄鲁直的没有关连。这解释并不能表现出雕刻艺人王叔远'奇巧... 《核舟记》:'佛印绝类弥勒,袒胸露乳,矫首昂视,神情与苏、黄不属。'文中对'不属'二字的注释是'〔不属(zhǔ)〕不相关连。'意即佛印的神情和苏轼、黄鲁直的没有关连。这解释并不能表现出雕刻艺人王叔远'奇巧'的技艺,令人费解。为什么课文会这样注释呢?我查了一下《说文解字》(以下简称《说文》)。 展开更多
关键词 “不属” 课文注释 《核舟记》 初中 语文 修改建议 文言文
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RBF neural network regression model based on fuzzy observations 被引量:1
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作者 朱红霞 沈炯 苏志刚 《Journal of Southeast University(English Edition)》 EI CAS 2013年第4期400-406,共7页
A fuzzy observations-based radial basis function neural network (FORBFNN) is presented for modeling nonlinear systems in which the observations of response are imprecise but can be represented as fuzzy membership fu... A fuzzy observations-based radial basis function neural network (FORBFNN) is presented for modeling nonlinear systems in which the observations of response are imprecise but can be represented as fuzzy membership functions. In the FORBFNN model, the weight coefficients of nodes in the hidden layer are identified by using the fuzzy expectation-maximization ( EM ) algorithm, whereas the optimal number of these nodes as well as the centers and widths of radial basis functions are automatically constructed by using a data-driven method. Namely, the method starts with an initial node, and then a new node is added in a hidden layer according to some rules. This procedure is not terminated until the model meets the preset requirements. The method considers both the accuracy and complexity of the model. Numerical simulation results show that the modeling method is effective, and the established model has high prediction accuracy. 展开更多
关键词 radial basis function neural network (RBFNN) fuzzy membership function imprecise observation regression model
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THRESHOLD STRESS INTENSITIES FOR HYDROGEN-INDUCED DELAYED FAILURE OF WELD METAL OF AUSTENITIC STAINLESS STEEL
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作者 潘川 李正邦 +3 位作者 田志凌 梁东图 褚武扬 乔利杰 《Transactions of Tianjin University》 EI CAS 2001年第3期147-152,共6页
It was found that hydrogen induced delayed failure could occur in 308L and 347L weld metals,and the threshold stress intensities of 308L and 347L welds were lower than that of 304L austenitic stainless steel.When dyn... It was found that hydrogen induced delayed failure could occur in 308L and 347L weld metals,and the threshold stress intensities of 308L and 347L welds were lower than that of 304L austenitic stainless steel.When dynamically charged under load on a single edge notched specimen,the threshold stress intensities of 308L,347L and 304L decrease with the increase in the diffusible hydrogen content C 0 and the experimental results are as follows:K ⅠH =85.2-10.7 ln C 0 (308L),K ⅠH =76.1-9.3 ln C 0 (347L),K ⅠH =91.7-10.1 ln C 0 (304L).The morphology of the hydrogen induced delayed fracture in the three materials are correlated with the K Ⅰ and C 0 values. 展开更多
关键词 austenitic stainless steel weld metal hydrogen induced delayed failure
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Resistivity Instability in Polysilicon Resistors Under Metal Interco-nnects and Its Suppression by Compensating Ion Implantation
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作者 余宁梅 高勇 陈治明 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第4期511-515,共5页
The resistivity instability of the boron-doped polysilicon resistors being a line resistance element of ICs is within the range of several kΩ's,especially when our running the underneath metal interconnects.Polys... The resistivity instability of the boron-doped polysilicon resistors being a line resistance element of ICs is within the range of several kΩ's,especially when our running the underneath metal interconnects.Polysilicon resistors have been fabricated under various processing conditions as well as some electrical and crystallographic characteristics have been obtained.It is shown the resistivity instability mainly results from the variational carrier mobility.By analyzing the Seto's model,the barrier height and trapped charge density are observed reducing under the Al over layer.Therefore,the resistance instability is also caused by both the charge trapping/detrapping occurring at polysilicon grain boundaries and the resultant variation in the potential barrier height.The formation of high-stability polysilicon resistors in the range of several kΩ's has been decided by compensating the ion implantation,which makes the charge trapping/detrapping at the grain boundary less susceptible to the hydrogen annealing. 展开更多
关键词 POLYSILICON INTERCONNECT
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Effect of intermetallic compounds on heat resistance of hot roll bonded titanium alloy-stainless steel transition joint 被引量:4
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作者 赵东升 闫久春 刘玉君 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第7期1966-1970,共5页
The effect of intermetallic compounds on the heat resistance of transition joint was investigated. The experiment of post-weld heat treatment for the hot roll bonded titanium alloy-stainless steel joint using nickels ... The effect of intermetallic compounds on the heat resistance of transition joint was investigated. The experiment of post-weld heat treatment for the hot roll bonded titanium alloy-stainless steel joint using nickels interlayer was carried out, and the interface microstructure evolution due to heat treatment was presented. There was not found significant interdiffusion at stainless steel/nickel interface, when the specimens were heat treated in the temperature range of 600-800 °C for 10 and 30 min, while micro-cracks occurred at the stainless steel/nickel interface heat treated at 700 °C for 30 min. The thickness of intermetallic layers at nickel/titanium alloy interface increased at 600 °C, and micro-cracks occurred at 700 and 800 °C. The micro-cracks occurred between intermetallic layers or between intermetallic layer and nickel interlayer as well. The tensile strength of the transition joint decreased with the increase of heat treatment temperature or holding time. 展开更多
关键词 INTERMETALLICS titanium alloy stainless steel transition joint heat resistance heat treatment hot roll bonding
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Influences of different filler metals on electron beam welding of titanium alloy to stainless steel 被引量:10
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作者 王廷 张秉刚 冯吉才 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第1期108-114,共7页
Electron beam welding experiments of titanium alloy to stainless steel were carried out with different filler metals, such as Ni, V, and Cu. Microstructures of the joints were examined by optical microscopy, scanning ... Electron beam welding experiments of titanium alloy to stainless steel were carried out with different filler metals, such as Ni, V, and Cu. Microstructures of the joints were examined by optical microscopy, scanning electron microscopy and X-ray diffraction analysis. Mechanical properties of the joints were evaluated according to tensile strength and microhardness. As a result, influences of filler metals on microstructures and mechanical properties of electron beam welded titanium-stainless steel joints were discussed. The results showed that all the filler metals were helpful to restrain the Ti-Fe intermetallics. The welds with different filler metals were all characterized by solid solution and interfacial intermetallics. For each type of the filler metal, the type of solid solution and interfacial intermetallics depended on the metallurgical reactions between the filler metals and base metals. The interfacial intermetallics were Fe2Ti+Ni3Ti+NiTi2, TiFe, and Cu2Ti+CuTi+CuTi2 in the joints welded with Ni, V, and Cu filler metals, respectively. The tensile strengths of the joints were dependent on the hardness of the interfacial intermetallics. The joint welded with Ag filler metal had the highest tensile strength, which is about 310 MPa. 展开更多
关键词 titanium alloy stainless steel filler metal electron beam welding mechanical property
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Welding of shape memory alloy to stainless steel for medical occluder 被引量:3
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作者 吕世雄 杨仲林 董红刚 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期156-160,共5页
Dissimilar metal joining between NiTi shape memory alloy(SMA) and stainless steel was conducted.A cluster of NiTi SMA wires were first joined with tungsten inert gas(TIG) welding process,then the NiTi SMA TIG weld... Dissimilar metal joining between NiTi shape memory alloy(SMA) and stainless steel was conducted.A cluster of NiTi SMA wires were first joined with tungsten inert gas(TIG) welding process,then the NiTi SMA TIG weld was welded to a stainless steel pipe with laser spot welding process.The microstructure of the welds was examined with an optical microscope and the elemental distribution in the welds was measured by electron probe microanalysis(EPMA).The results show that TiC compounds dispersively distribute in the NiTi SMA TIG weld.However,the amount of TiC compounds greatly decreases around the fusion boundary of the laser spot weld between the NiTi SMA and stainless steel.Mutual diffusion between NiTi shape memory alloy and stainless steel happen within a short distance near the fusion boundary,and intermetallic compounds such as Ni3Ti+(Fe,Ni)Ti appear around the fusion boundary. 展开更多
关键词 medical occluder NiTi alloy shape memory alloy stainless steel laser spot welding dissimilar metal joining Ni3Ti (Fe Ni)Ti
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p53 antibodies,metallothioneins,and oxidative stress markers in chronic ulcerative colitis with dysplasia 被引量:6
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作者 Hala E Hamouda Soha S Zakaria +2 位作者 Saber A Ismail Mahmoud A Khedr Wael W Mayah 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第19期2417-2423,共7页
AIM:To investigate the role of p53 antibodies (p53Abs),metallothioneins (MTs) and oxidative stress markers in the early detection of dysplasia in chronic ulcerative colitis (UC).METHODS:The study included 30 UC patien... AIM:To investigate the role of p53 antibodies (p53Abs),metallothioneins (MTs) and oxidative stress markers in the early detection of dysplasia in chronic ulcerative colitis (UC).METHODS:The study included 30 UC patients,15 without dysplasia (group Ⅱ) and 15 with dysplasia (group Ⅲ),in addition to 15 healthy volunteers (group Ⅰ,control subjects).The enzyme-linked immunosorbent assay technique was used to measure serum p53Abs and MTs,while advanced oxidation protein products (AOPPs),and reduced glutathione (GSH) levels were measured by spectrophotometric method in all subjects.RESULTS:In group Ⅱ and group Ⅲ compared to group Ⅰ,there were significant increases in serum levels of AOPPs (145.94 ± 29.86 μmol/L and 192.21 ± 46.71 μmol/L vs 128.95 ± 3.06 μmol/L,P < 0.002 and P <0.001,respectively),MTs (8.18 ± 0.35 μg/mL and 9.20 ± 0.58 μg/mL vs 6.12 ± 0.25 μg/mL,P < 0.05 and P < 0.05,respectively),and p53Abs (20.19 ± 3.20 U/mL and 34.66 ± 1.34 U/mL vs 9.42 ± 1.64 U/mL,P < 0.001 and P < 0.001,respectively).There were significantly higher levels of AOPPs (P < 0.05) and p53Abs (P < 0.001) in UC patients with dysplasia compared to those without dysplasia,while MTs showed no significant difference between the 2 groups (P > 0.096).In contrast,GSH levels showed a significant decrease in both patients' groups (1.87 ± 0.02 μmol/mL and 1.37 ± 0.09 μmol/mL vs 2.49 ± 0.10 μmol/mL,P < 0.05 and P < 0.05 in groups Ⅱ and Ⅲ,respectively) compared with group Ⅰ,and the levels were significantly lower in group Ⅲ than group Ⅱ (P < 0.05).There was a positive correlation between AOPPs and both MTs (r=0.678,P < 0.001) and p53Abs (r=0.547,P < 0.001),and also between p53Abs and MTs (r=0.739,P < 0.001).There was a negative correlation between AOPPs and GSH (r =-0.385,P < 0.001),and also between GSH and both MTs (r=-0.662,P < 0.001) and p53Abs (r=-0.923,P < 0.001).CONCLUSION:Oxidative stress and oxidative cellular damage play an important role in the pathogenesis of chronic UC and the associated carcinogenetic process.p53Abs levels could help in early detection of dysplasia in these conditions. 展开更多
关键词 Ulcerative colitis Advanced oxidation protein products Reduced glutathione METALLOTHIONEIN
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Local inhomogeneity of mechanical properties in stir zone of friction stir welded AA1050 aluminum alloy 被引量:8
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作者 Xiao-chao LIU Yun-qian ZHEN +4 位作者 Yu-feng SUN Zhi-kang SHEN Hai-yan CHEN Wei GUO Wen-ya LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第9期2369-2380,共12页
The local inhomogeneity of the stir zone in friction stir welded face-centered cubic metal was investigated,which has multiple activated slip systems during plastic deformation,by selecting commercial AA1050 aluminum ... The local inhomogeneity of the stir zone in friction stir welded face-centered cubic metal was investigated,which has multiple activated slip systems during plastic deformation,by selecting commercial AA1050 aluminum alloy as an ideal experimental material.The local inhomogeneity was evaluated by uniaxial tensile tests using small samples with a 1 mm gauge length.The corresponding microstructural parameters such as grain size,misorientation angle distribution,and micro-texture,were quantified by the backscattered electron diffraction technique.A comprehensive model was used to reveal the microstructure−mechanical property relationship.The experimental results showed that the uniaxial tensile property changes significantly across the weld.The maximum ultimate tensile strength(UTS)occurred in the center of the stir zone,which was 99.0 MPa.The weakest regions were located at the two sides of the stir zone.The largest difference value in UTS reached 14.9 MPa,accounting for 15%of the maximum UTS.The analysis on the structure−mechanical property relationship suggests that the micro-texture change with the location formed during the rotational material flow is the main reason for the local inhomogeneity. 展开更多
关键词 friction stir welding face-centered cubic metal local inhomogeneity mechanical properties MICRO-TEXTURE
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Aerobic biodegradation of diethyl phthalate by Acinetobacter sp. JDC-16 isolated from river sludge 被引量:7
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作者 梁任星 吴学玲 +2 位作者 王兴娜 代沁芸 王洋洋 《Journal of Central South University》 SCIE EI CAS 2010年第5期959-966,共8页
A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological an... A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological and biochemical properties and analysis of 16S rRNA gene sequence,it was preliminarily identified belonging to the genus Acinetobacter.The result of substrates utilization range indicates that strain JDC-16 can utilize a variety of phthalates except for diisononyl phthalate(DINP) .The degradation tests using diethyl phthalate(DEP) as the model compound show that the optimal pH and temperature for DEP degradation by Acinetobacter sp.JDC-16 is 8.0 and 35℃,respectively.Meanwhile,degradation kinetics under various initial concentrations of DEP reveals that substrate depletion curves fit well with the modified Gompertz model with high correlation coefficient(R 2 >0.99) .Furthermore,the substrate induction test indicates that DEP-induction can apparently shorten the lag phase and enhance the degradation rate.This work highlights the potential of this isolate for bioremediation of phthalates-contaminated environments. 展开更多
关键词 BIODEGRADATION diethyl phthalate KINETICS Acinetobacter sp. river sludge
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Partial transient-liquid-phase bonding of TiC cermet to stainless steel using impulse pressuring with Ti/Cu/Nb interlayer 被引量:1
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作者 黄利 盛光敏 +2 位作者 李佳 黄光杰 袁新建 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第5期1025-1032,共8页
Partial transient liquid phase (PTLP) bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate ... Partial transient liquid phase (PTLP) bonding of TiC cermet to 06Cr19Ni10 stainless steel was carried out. Impulse pressuring was used to reduce the bonding time, and a Ti/Cu/Nb interlayer was employed to alleviate the detrimental effect of interfacial reaction products on the bonding strength. Successful bonding was achieved at 885℃ under a pulsed pressure of 2-10 MPa within durations in the range of 2-8 min, which was notably shortened in comparison with conventional PTLP bonding. Microstructure characterization revealed the o- phase with a limit solubility of Nb, a sequence of Ti-Cu intermetallic phases and solid solutions of Ni and Cu in α+β Ti in the reaction zone. The maximum shear strength of 106.7 MPa was obtained when the joint was bonded for 5 rain, indicating that a robust metallurgical bonding was achieved. Upon shear loading, the joints fractured along the Ti-Cu intermetallics interface and spread to the interior of TiC cermet in a brittle cleavage manner. 展开更多
关键词 TiC cermet transient liquid phase impulse pressuring mechanical property fracture
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Study of Pitting Morphology Fractal Characteristic of Corroded Surface of 304 Stainless Steel in FeCl_3 Environment 被引量:4
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作者 张玮 梁成浩 《Journal of China University of Mining and Technology》 2004年第1期86-89,共4页
Experiments were performed to study the pitting corrosion morphology of 304 stainless steel exposed to FeCl 3 environments and SEM micrographs of the pitting corrosion morphology were obtained. The image processing te... Experiments were performed to study the pitting corrosion morphology of 304 stainless steel exposed to FeCl 3 environments and SEM micrographs of the pitting corrosion morphology were obtained. The image processing technique combining with the fractal method was employed to analyze these pitting corrosion images and the self-similarity of pits morphology was observed. It indicates that fractal characteristics exist in pitting corrosion of 304 stainless steel. The self-similarity and complexity of the pitting morphology phenomenon were described in terms of fractal dimension which can also be an important parameter related to characterize pitting morphology qualitatively and quantitatively. 展开更多
关键词 FRACTAL corrosion morphology pitting corrosion 304 stainless steel image processing
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SU(3) Simple Group Model and New Z' Properties in Future Linear Colliders
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作者 LIU Yao-Bei WANG Shuai-Wei ZHANG Wen-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第2期299-304,共6页
In the SU(3) simple group model, the new neutral gauge boson Z' couples to pairs of SM fermions with couplings fixed in terms of the SM gauge couplings and depending only on the choice of the fermion embedding. In ... In the SU(3) simple group model, the new neutral gauge boson Z' couples to pairs of SM fermions with couplings fixed in terms of the SM gauge couplings and depending only on the choice of the fermion embedding. In this paper, we calculate the contributions of this new particle to the processes e^+e^-→l^+l^-, bb^-, and cc^- and study the possibility of detecting this new particle via these processes in the future high-energy linear e^+e^- collider(LC) experiments with √s= 500 GeV and £int= 340 fb^-1. We find that the new gauge boson Z' is most sensitive to the process e^+e^-→b^+b^-. As long as Mz,≤2 TeV , the absolute values of the relative correction parameter are larger than 5%. We calculate the forward-backward asymmetries and left-right asymmetries for the process e^+e^-→c^+c^-, with both the universal and anomaly-free fermion embeddings. Bounds on Z' masses are also estimated within 95% confidence level. 展开更多
关键词 SU(3) simple group model relative corrections forward-backward asymmetry left-right asymme-try new gauge boson
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Convexity Condition for a Class of Operator
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作者 LU Da-qian LIU Jin-lin 《Chinese Quarterly Journal of Mathematics》 CSCD 2011年第2期185-189,共5页
In this paper,we find a subclass of starlike functions on the unit disk,which are mapped by a operator,given by F(z)=1+u/zu∫z0 f(t)tu-1dt(Re u≥0),onto convex functions.The main results extend some known results.
关键词 differential subordination DOMINANT integral operator
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Analysis of semi-solid response under rapid compression tests using multi-scale modelling and experiments 被引量:3
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作者 V.FAVIER H.ATKINSON 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1691-1695,共5页
Simulating semi-solid metal forming requires modelling semi-solid behaviour.However, such modelling is difficult because semi-solid behavior is thixotropic and depends on the liquid-solid spatial distribution within t... Simulating semi-solid metal forming requires modelling semi-solid behaviour.However, such modelling is difficult because semi-solid behavior is thixotropic and depends on the liquid-solid spatial distribution within the material.In order to better understand and model relationships between microstructure and behavior, a model based on micromechanical approaches and homogenisation techniques is presented.This model is an extension of a previous model established in a pure viscoplastic framework to account for elasticity.Indeed, experimental load-displacement signals reveal the presence of an elastic-type response in the earlier stages of deformation when semi-solids are loaded under rapid compression.This elastic feature of the behaviour is attributed to the response of the porous solid skeleton saturated by incompressible liquid.A good quantitative agreement is found between the elastic-viscoplastic predicted response and the experimental data.More precisely, the strong initial rising part of the load-displacement curve, the peak load and the subsequent fall in load are well captured.The effect of solid fraction on mechanical response is in qualitative agreement with experiments. 展开更多
关键词 semi-solid metal aluminium solid fraction elastic-viscoplasticity HOMOGENIZATION
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Thermal performance of sputtered Cu films containing insoluble Zr and Cr for advanced barrierless Cu metallization
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作者 王新建 董显平 姜传海 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第2期217-222,共6页
Pure Cu films and Cu alloy films containing insoluble substances(Zr and Cr)were deposited on Si(100)substrates,in the presence of interfacial native suboxide(SiOx),by magnetron sputtering.Samples were vacuum annealed ... Pure Cu films and Cu alloy films containing insoluble substances(Zr and Cr)were deposited on Si(100)substrates,in the presence of interfacial native suboxide(SiOx),by magnetron sputtering.Samples were vacuum annealed between 300℃and 500 ℃to investigate effects of Zr and Cr additions on the thermal performance of Cu films.After annealing,copper silicides were found in the Cu(Zr)films,while no detectable silicides were observed in Cu and Cu(Cr)films.Upon annealing,Zr accelerated the diffusion and reaction between the film and the substrate,and lowered the thermal stability of Cu(Zr)alloy films on Si substrates,which was ascribed to the‘purifying effect’of Zr on the Si substrates.Whereas,Cr prohibited the agglomeration of Cu films at 500℃and decreased the surface roughness.As a result,the diffusion of Cu in Si substrates for Cu(Cr)films was effectively inhibited.In contrast to the high resistivity of Cu(Zr)films,the final resistivity of about 2.76μΩ·cm was achieved for the Cu(Cr)film.These results indicate that Cu(Cr)films have higher thermal stability than Cu(Zr)films on Si substrates and are preferable in the advanced barrierless Cu metallization. 展开更多
关键词 copper film barrierless metallization magnetron sputtering thermal stability purifying effect
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The effects of TiO_(2)crystal-plane-dependent Ir-TiO_(x)interactions on the selective hydrogenation of crotonaldehyde over Ir/TiO_(2)catalysts 被引量:2
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作者 Aiping Jia Yunshang Zhang +5 位作者 Tongyang Song Yiming Hu Wanbin Zheng Mengfei Luo Jiqing Lu Weixin Huang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第10期1742-1754,共13页
Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)... Three supported Ir/TiO_(2)catalysts,containing anatase TiO_(2)nanocrystals with predominantly exposed{101},{100},and{001}planes,were subjected to various pre-treatments(H2 reduction at different temperatures and O_(2)re-oxidation)and then tested in the vapor phase selective hydrogenation of crotonaldehyde.The pre-treatments significantly altered the Ir-TiO_(x)interactions,including the morphologies and electronic properties of the Ir species and their surface acidity.These interactions were also closely related to the crystal planes of TiO_(2),which further supported the observed reaction behaviors of the various Ir/TiO_(2)catalysts.The best performance was obtained using the Ir/TiO_(2)-{101}catalyst pre-reduced at 300℃,owing to its higher Ir^(0)surface concentration and moderate surface acidity compared to the other catalysts.Moreover,these findings indicated the synergistic role of the Ir-TiO_(x)interface in the reaction,as the interfacial sites were responsible for the adsorption/activation of H_(2)and the C=O bond in the crotonaldehyde molecule.However,pre-reduction at 400℃resulted in partial encapsulation of the Ir particles by TiO_(x)via strong metal-support interactions,which is unfavorable for the catalytic reaction owing to the loss of Ir-TiO_(x)interfacial sites. 展开更多
关键词 HYDROGENATION α β-unsaturated aldehyde Ir/TiO_(2) Metal-support interactions Surface acidity
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Congestion aware routing algorithm for delay-disruption tolerance networks 被引量:4
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作者 陶勇 龚正虎 +1 位作者 林亚平 周四望 《Journal of Central South University》 SCIE EI CAS 2011年第1期133-139,共7页
There were many contradictory evaluation criteria to select next-hop in the delay-disruption tolerance networks(DTN).To solve this problem,an attribute hierarchical model was proposed,in which the predefined criteria ... There were many contradictory evaluation criteria to select next-hop in the delay-disruption tolerance networks(DTN).To solve this problem,an attribute hierarchical model was proposed,in which the predefined criteria were summarized as static identity attributes,forwarding desire attributes and delivery capability attributes(IDC).Based on this model,a novel multi-attributes congestion aware routing(MACAR) scheme with uncertain information for next-hop selection was presented,by adopting an decision theory to aggregate attributes with belief structure and computing partial ordering relations.The simulation results show that MACAR presents higher successful delivery rate,lower average delay and effectively alleviate congestion. 展开更多
关键词 delay-disruption tolerant network congestion control routing algorithm custody transfer
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Stabilization design for continuous-time Takagi-Sugeno fuzzy systems based on new relaxed conditions
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作者 潘俊涛 费树岷 +1 位作者 穆朝絮 薛明香 《Journal of Southeast University(English Edition)》 EI CAS 2010年第4期550-553,共4页
This paper deals with the problem of stabilization design for a class of continuous-time Takagi-Sugeno(T-S)fuzzy systems.New stabilization conditions are derived based on a relaxed approach in which both fuzzy Lyapu... This paper deals with the problem of stabilization design for a class of continuous-time Takagi-Sugeno(T-S)fuzzy systems.New stabilization conditions are derived based on a relaxed approach in which both fuzzy Lyapunov functions and staircase membership functions are used.Through the staircase membership functions approximating the continuous membership functions of the given fuzzy model,the information of the membership functions can be brought into the stabilization design of the fuzzy systems,thereby significantly reducing the conservativeness in the existing stabilization conditions of the T-S fuzzy systems.Unlike some previous fuzzy Lyapunov function approaches reported in the literature,the proposed stabilization conditions do not depend on the time-derivative of the membership functions that may be the main source of conservatism when considering fuzzy Lyapunov functions analysis.Moreover,conditions for the solvability of the controller design are written in the form of linear matrix inequalities,but not bilinear matrix inequalities,which are easier to be solved by convex optimization techniques.A simulation example is given to demonstrate the validity of the proposed approach. 展开更多
关键词 Takagi-Sugeno fuzzy model fuzzy Lyapunov function staircase membership function linear matrix inequality
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The synthesis of tetracyclic coumarins via decarboxylative asymmetric[4+2]cycloadditions enabled by Pd(0)/Cu(I)synergistic catalysis
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作者 Kai Wang Xiangfeng Lin +2 位作者 Qian Li Yan Liu Can Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第7期1812-1817,共6页
Tetracyclic coumarins are a class of important compounds with diverse and superior pharmacolog‐ical activities.However,a direct stereoselective method from simple and readily‐made coumarins derivatives remains chall... Tetracyclic coumarins are a class of important compounds with diverse and superior pharmacolog‐ical activities.However,a direct stereoselective method from simple and readily‐made coumarins derivatives remains challenging due to the inertness of coumarins as dienophiles.Herein,we de‐velop a decarboxylative asymmetric[4+2]cycloaddition of 3‐cyanocoumarins with vinyl benzoxa‐zinones,affording the coumarin‐derived condensed rings bearing three continuous stereocenters in high yields with excellent diastereoselectivities(>20/1 d.r.)and enantioselectivities(up to 99%ee).This direct enantioselective reaction was achieved by a Pd(0)/Cu(I)bimetallic catalytic system.The mechanism studies indicated that the synergistic activation effect,in which chiral Cu(I)as an availa‐ble Lewis acid catalyst activates 3‐cyanocoumarin and chiral Pd(0)complex activates benzoxazi‐none by the formation ofπ‐allyl‐palladium intermediate,plays an important role on the stereoselec‐tive control.The current work provides a new activation modes of Cu catalyst in the Pd/Cu bimetal‐lic catalytic system. 展开更多
关键词 Synergistic catalysis Pd(0)/Cu(I)catalysis Asymmetric catalysis [4+2]Cycloaddition Tetracyclic coumarins Chiral catalysis
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