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TiO_(2)相结的可控合成及其在光催化降解室内甲醛中的应用
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作者 贾宝丽 《能源化工》 CAS 2024年第3期73-78,共6页
通过焙烧法成功制备了a-TiO_(2)/r-TiO_(2)相结试样。XRD和Raman分析表明,通过改变焙烧时间实现了试样中a-TiO_(2)和r-TiO_(2)的含量调控。在光催化降解甲醛试验中,所有a-TiO_(2)/r-TiO_(2)相结试样的活性均高于纯a-TiO_(2)和r-TiO_(2)... 通过焙烧法成功制备了a-TiO_(2)/r-TiO_(2)相结试样。XRD和Raman分析表明,通过改变焙烧时间实现了试样中a-TiO_(2)和r-TiO_(2)的含量调控。在光催化降解甲醛试验中,所有a-TiO_(2)/r-TiO_(2)相结试样的活性均高于纯a-TiO_(2)和r-TiO_(2)试样。其中组成(w)为47.6%a-TiO_(2)+52.4%r-TiO_(2)试样的活性最佳,经过5 h光照后甲醛降解率达到了96.9%,反应速率分别为纯a-TiO_(2)和r-TiO_(2)试样的13.6和24.5倍。表面光电压谱和光电流曲线分析表明光催化活性差异的主要原因是a-TiO_(2)/r-TiO_(2)相结促进了光生载流子分离效率,进而提高光催化活性。 展开更多
关键词 a-TiO_(2)/r-TiO_(2) 光催化 甲醛 光生载流子
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表面相结结构在促进光催化电荷分离中的应用(英文) 被引量:1
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作者 马艺 王秀丽 李灿 《催化学报》 SCIE EI CAS CSCD 北大核心 2015年第9期1519-1527,共9页
二十世纪八十年代以来,特别是近十年,光催化研究在利用可再生能源太阳能的道路上飞速发展.越来越多的研究表明,相结结构的构筑是有效提高半导体光催化剂性能的重要策略.其中,TiO2作为重要的模型光催化剂,其相关研究成果呈现出指数增长... 二十世纪八十年代以来,特别是近十年,光催化研究在利用可再生能源太阳能的道路上飞速发展.越来越多的研究表明,相结结构的构筑是有效提高半导体光催化剂性能的重要策略.其中,TiO2作为重要的模型光催化剂,其相关研究成果呈现出指数增长的趋势.本综述围绕TiO2模型光催化剂,主要介绍TiO2表面相结的研究成果,包括TiO2表面相的表征、锐钛矿:金红石TiO2相结用于光催化产氢研究、TiO2相结在光催化中作用的最新认识等.在表征方面,通过表面灵敏的紫外拉曼光谱研究了TiO2相变过程中表面相结构的变化,结合可见拉曼以及XRD表征揭示了TiO2独特的相变过程,即相变始于锐钛矿粒子的界面处,小粒子逐渐团聚为大粒子,致其相变从大粒子体相开始最终扩展到整个粒子.使用CO,CO2探针红外光谱,根据锐钛矿和金红石表面吸附物种的差异,进一步证实了锐钛矿:金红石表面相结结构,为紫外拉曼光谱的表面表征特性提供坚实证据.同时,利用发光光谱观察到锐钛矿晶相的可见发光带和金红石晶相的近红外发光带,并基于此给出了TiO2材料表面相结结构的荧光表征新方法.此外荧光光谱还提供了锐钛矿、金红石相中载流子动力学信息,揭示了束缚态在光催化中的作用.在光催化应用方面,观察到混相结构TiO2较单独锐钛矿及金红石相具有更高的光催化产氢活性,通过在较大金红石颗粒上担载纳米锐钛矿粒子,证明了相结结构在提高光催化活性中的核心作用,并首次提出了锐钛矿:金红石表面异相结结构概念,推断其对电荷分离的促进作用是最终提高反应活性的原因.之后将此概念应用到改善商品TiO2(P25)光催化活性中,通过可控热处理精细调控P25的表面相结构,在光催化重整生物质衍生物产氢实验中,成功将P25光催化产氢活性提高3-5倍.之后发展了新的TiO2表面控制方法,通过加入Na2SO4等相变控制剂,延缓了TiO2从锐钛矿向金红石的相变过程,在较高温度下实现TiO2相结结构的调控,最终可将P25光催化重整甲醇制氢的活性提高6倍,同时通过高分辨电镜清晰观察到锐钛矿:金红石相结的原子层生长接触.在相结作用机理方面,多种时间分辨光谱技术以及理论计算被用作探索锐钛矿:金红石相结处的电子转移机理.通过时间分辨红外光谱对TiO2表面相结结构作用的研究,特别是利用锐钛矿、金红石不同的瞬态吸收光谱特征,证明了锐钛矿:金红石相结处的载流子转移过程,存在锐钛矿向金红石的电子转移过程.模型光催化剂TiO2相结的研究成果,加深了对光催化机理的认识,促进新型高效光催化体系的设计合成. 展开更多
关键词 光催化 表面 电荷分离 太阳能 二氧化钛
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基于相对灰色关联度的采矿方法优选 被引量:3
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作者 邓建 邓顺华 《湖南有色金属》 CAS 北大核心 1996年第5期9-12,43,共5页
针对多目标方案决策的特点,本文提出了相对关联度的基本原理及应用于采矿方法优选的步骤。并实例验证.是对运用单一灰色关联度进行方案决策的一次尝试性突破。
关键词 灰色系统 结关联度 采矿方法优选
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Interface engineering via temperature-dependent self-transformation on SnS2/SnS for enhanced piezocatalysis
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作者 Wenrou Tian Jun Han +4 位作者 Najun Li Dongyun Chen Qingfeng Xu Hua Li Jianmei Lu 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第9期166-179,共14页
Heterojunction has been widely used in vibration-driven piezocatalysis for enhanced charges separation,while the weak interfaces seriously affect the efficiency during mechanical deformations due to prepared by tradit... Heterojunction has been widely used in vibration-driven piezocatalysis for enhanced charges separation,while the weak interfaces seriously affect the efficiency during mechanical deformations due to prepared by traditional step-by-step methods.Herein,the intimate contact interfaces with shared S atoms are ingeniously constructed in SnS_(2)/SnS anchored on porous carbon by effective interface engineering,which is in-situ derived from temperature-dependent self-transformation of SnS_(2).Benefiting from intimate contact interfaces,the piezoelectricity is remarkably improved due to the larger interfacial dipole moment caused by uneven distribution of charges.Importantly,vibration-induced piezoelectric polarization field strengthens the interfacial electric field to further promote the separation and migration of charges.The dynamic charges then transfer in porous carbon with high conductivity and adsorption for significantly improved piezocatalytic activity.The degradation efficiency of bisphenol A(BPA)is 6.3 times higher than SnS_(2) and H2 evolution rate is increased by 3.8 times.Compared with SnS_(2)/SnS prepared by two-step solvothermal method,the degradation efficiency of BPA and H2 evolution activity are increased by 3 and 2 times,respectively.It provides a theoretical guidance for developing various multiphase structural piezocatalyst with strong interface interactions to improve the piezocatalytic efficiency. 展开更多
关键词 Piezocatalysis SELF-TRANSFORMATION Phase junction Interfacial field Polarized field
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Time-dependent effects in transient liquid phase bonding of 304L and Cp-Ti using an Ag-Cu interlayer
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作者 Saeed VAZIRIAN Mohammad MOSHKBAR BAKHSHAYESH Ali FARZADI 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2237-2255,共19页
One of the challenges for bimetal manufacturing is the joining process.Hence,transient liquid phase(TLP)bonding was performed between 304L stainless steel and Cp-Ti using an Ag-Cu interlayer with a thickness of 75μm ... One of the challenges for bimetal manufacturing is the joining process.Hence,transient liquid phase(TLP)bonding was performed between 304L stainless steel and Cp-Ti using an Ag-Cu interlayer with a thickness of 75μm for bonding time of 20,40,60,and 90 min.The bonding temperature of 860℃ was considered,which is under the β transus temperature of Cp-Ti.During TLP bonding,various intermetallic compounds(IMCs),including Ti_(5)Cr_(7)Fe_(17),(Cr,Fe)_(2)Ti,Ti(Cu,Fe),Ti_(2)(Cu,Ag),and Ti_(2)Cu from 304L toward Cp-Ti formed in the joint.Also,on the one side,with the increase in time,further diffusion of elements decreases the blocky IMCs such as Ti_(5)Cr_(7)Fe_(17),(Cr,Fe)_(2)Ti,Ti(Cu,Fe)in the 304L diffusion-affected zone(DAZ)and reaction zone,and on the other side,Ti_(2)(Cu,Ag)IMC transformed into fine morphology toward Cp-Ti DAZ.The microhardness test also demonstrated that the(Cr,Fe)_(2)Ti+Ti_(5)Cr_(7)Fe_(17) IMCs in the DAZ on the side of 304L have a hardness value of HV 564,making it the hardest phase.The maximum and minimum shear strength values are equal to 78.84 and 29.0 MPa,respectively.The cleavage pattern dominated fracture surfaces due to the formation of brittle phases in dissimilar joints. 展开更多
关键词 diffusion brazing transient liquid phase bonding dissimilar material joints microstructural evolution mechanical properties grade 2 titanium
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试谈中国实施林纸一体化存在的问题及其对策——简介光叶楮林纸结合与水土保持工程相结合的建议
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作者 聂勋载 余保安 《江苏造纸》 2013年第2期2-8,共7页
中国造纸工业经过改革开放30多年的不懈努力,取得巨大成就面目为之一新,巳成为世界第一造纸大国。但中国还不是造纸强国,还有很多难题困扰着中国造纸工业独立创新的进一步发展。尤其是“造纸原料供求矛盾突出”,而且越来越严重,原... 中国造纸工业经过改革开放30多年的不懈努力,取得巨大成就面目为之一新,巳成为世界第一造纸大国。但中国还不是造纸强国,还有很多难题困扰着中国造纸工业独立创新的进一步发展。尤其是“造纸原料供求矛盾突出”,而且越来越严重,原料是制约中国造纸工业发展的瓶颈。今后中国造纸工业还需要稳步的较快发展,所需原料还想靠扩大进口的潜力有限。原料问题只能依靠国内自行去解决,要全方位多管齐下,千方百计争取将中国造纸工业的原料基本立足于国内。本文重点谈“中国造纸工业林纸一体化存在的问题及对策”。提出我国林纸结合的关键是造纸企业与山农在林权和林地经营权的矛盾,这可能是造成我国“原料基地建设迟缓”的根本原因,本文反映了有关情况和矛盾,提出了意见和建议。本文亦简介我国林纸结合的另一种模式(或林纸结合的补充方案)“光叶楮林纸结合与水土保持工程相结”的建议。希望双管齐下更好的发展我国林纸结合,以求尽快解决我国造纸工业原料的严重短缺。 展开更多
关键词 林纸结合 林权和林地经营权 原料基地建设迟缓 光叶楮林纸结合与水土保持工程
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TiO_(2)相结纳米棒制备及其光催化深度脱除烟气汞的实验研究 被引量:2
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作者 赵晏锋 任思源 +3 位作者 吴江 季仲昊 马前 杨茉 《动力工程学报》 CAS CSCD 北大核心 2021年第11期979-983,1018,共6页
采用溶剂热法制备了不同形貌和不同晶相掺杂的TiO_(2)相结纳米棒,研究不同物质的量比下TiO_(2)的形貌及相结对光催化氧化脱汞性能的影响。结果表明:TB、ET、HAc与LiAc物质的量比为1∶20∶20∶5时,TiO_(2)纳米棒的性能最佳,光响应范围可... 采用溶剂热法制备了不同形貌和不同晶相掺杂的TiO_(2)相结纳米棒,研究不同物质的量比下TiO_(2)的形貌及相结对光催化氧化脱汞性能的影响。结果表明:TB、ET、HAc与LiAc物质的量比为1∶20∶20∶5时,TiO_(2)纳米棒的性能最佳,光响应范围可扩展到可见光;在可见光下光催化脱汞效率达到44.7%,且光催化剂的稳定性良好。 展开更多
关键词 溶剂热法 光催化剂 TiO_(2)纳米棒
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Tongue image feature correlation analysis in benign lung nodules and lung cancer
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作者 SHI Yulin LIU Jiayi +2 位作者 CHUN Yi LIU Lingshuang XU Jiatuo 《Digital Chinese Medicine》 CAS CSCD 2024年第2期120-128,共9页
Objective To analyze the differences in the correlation of tongue image indicators among patients with benign lung nodules and lung cancer.Methods From July 1;2020 to March 31;2022;clinical information of lung cancer ... Objective To analyze the differences in the correlation of tongue image indicators among patients with benign lung nodules and lung cancer.Methods From July 1;2020 to March 31;2022;clinical information of lung cancer patients and benign lung nodules patients was collected at the Oncology Department of Longhua Hos-pital Affiliated to Shanghai University of Traditional Chinese Medicine and the Physical Ex-amination Center of Shuguang Hospital Affiliated to Shanghai University of Traditional Chi-nese Medicine;respectively.We obtained tongue images from patients with benign lung nod-ules and lung cancer using the TFDA-1 digital tongue diagnosis instrument;and analyzed these images with the TDAS V2.0 software.The extracted indicators included color space pa-rameters in the Lab system for both the tongue body(TB)and tongue coating(TC)(TB/TC-L;TB/TC-a;and TB/TC-b);textural parameters[TB/TC-contrast(CON);TB/TC-angular second moment(ASM);TB/TC-entropy(ENT);and TB/TC-MEAN];as well as TC parameters(perAll and perPart).The bivariate correlation of TB and TC features was analyzed using Pearson’s or Spearman’s correlation analysis;and the overall correlation was analyzed using canonical correlation analysis(CCA).Results Samples from 307 patients with benign lung nodules and 276 lung cancer patients were included after excluding outliers and extreme values.Simple correlation analysis indi-cated that the correlation of TB-L with TC-L;TB-b with TC-b;and TB-b with perAll in lung cancer group was higher than that in benign nodules group.Moreover;the correlation of TB-a with TC-a;TB-a with perAll;and the texture parameters of the TB(TB-CON;TB-ASM;TB-ENT;and TB-MEAN)with the texture parameters of the TC(TC-CON;TC-ASM;TC-ENT;and TC-MEAN)in benign nodules group was higher than lung cancer group.CCA further demon-strated a strong correlation between the TB and TC parameters in lung cancer group;with the first and second pairs of typical variables in benign nodules and lung cancer groups indicat-ing correlation coefficients of 0.918 and 0.817(P<0.05);and 0.940 and 0.822(P<0.05);re-spectively.Conclusion Benign lung nodules and lung cancer patients exhibited differences in correla-tion in the L;a;and b values of the TB and TC;as well as the perAll value of the TC;and the texture parameters(TB/TC-CON;TB/TC-ASM;TB/TC-ENT;and TB/TC-MEAN)between the TB and TC.Additionally;there were differences in the overall correlation of the TB and TC be-tween the two groups.Objective tongue diagnosis indicators can effectively assist in the diag-nosis of benign lung nodules and lung cancer;thereby providing a scientific basis for the ear-ly detection;diagnosis;and treatment of lung cancer. 展开更多
关键词 Benign lung nodules Lung cancer Tongue image Correlation analysis Differential diagnosis
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Effect of Nd content on electrochemical performances of nanocrystalline and amorphous (Mg_(24)Ni_(10)Cu_2)_(100-x)Nd_x(x=0-20) alloys prepared by melt spinning 被引量:9
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作者 张羊换 杨泰 +3 位作者 卜文刚 蔡颖 张国芳 赵栋梁 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第12期3668-3676,共9页
The nanocrystalline and amorphous Mg2Ni-type alloys with a chemical composition of (Mg24Ni10Cu2)100-xNdx (x=0, 5, 10, 15, 20) were fabricated by melt spinning technology. The effects of spinning rate on the struct... The nanocrystalline and amorphous Mg2Ni-type alloys with a chemical composition of (Mg24Ni10Cu2)100-xNdx (x=0, 5, 10, 15, 20) were fabricated by melt spinning technology. The effects of spinning rate on the structure and electrochemical hydrogen storage performance of the alloys were investigated. The as-spun Nd-free alloy displays an entire nanocrystalline structure, whereas the as-spun Nd-added alloys hold a nanocrystalline and amorphous structure, suggesting that the addition of Nd facilitates the glass forming of the Mg2Ni-type alloys. Increasing the spinning rate from 0 to 40 m/s gives rise to the discharge capacity growing from 42.5 to 100.6 mA·h/g for the x=0 alloy and from 86.4 to 452.8 mA·h/g for the x=10 alloy. And the cycle stability (S20) rises from 40.2%to 41.1%for the x=0 alloy and from 53.2%to 89.7%for the x=10 alloy, respectively. 展开更多
关键词 hydrogen storage alloy Mg2Ni-type alloy ND melt spinning structure
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Fabrication of a monoclinic/hexagonal junction in WO_3 and its enhanced photocatalytic degradation of rhodamine B 被引量:14
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作者 卢圆圆 刘果 +3 位作者 张静 冯兆池 李灿 李智 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第3期349-358,共10页
A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction(XRD),scanning electron microscopy(SEM),high-resolution ... A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),X-ray photoelectron spectroscopy,and N2 adsorption-desorption were used to characterize the crystalline phase,morphology,particle size,chemical composition,and surface area of the WO3 samples.The formation of hexagonal(h-WO3) and monoclinic(m-WO3) crystal structures of WO3 at different temperatures or different times was confirmed by XRD.m-WO3 is formed at 600 ℃,while m-WO3 starts to transform into h-WO3 at 800℃.However,h-WO3,which forms at 800℃,may transform into m-WO3 by increasing the calcination temperature to 1000℃.SEM results indicate that m-WO3 particles exhibit a bulky shape with heavy aggregates,while h-WO3 particles exhibit a rod-like shape.Moreover,m-WO3 crystals are sporadically patched on the surface of the h-WO3 rod-like particles,resulting in the exposure of both m-WO3 and h-WO3 on the surface.It is observed that the monoclinic phase(m-WO3)/hexagonal phase(h-WO3) junction was fabricated by tuning the calcination temperature and calcination time.The relative ratios between m-WO3 and h-WO3 in the phase junction can readily be tailored by control of the calcination time.The photocatalytic activities of WO3 with different crystalline phases were evaluated by the photocatalytic degradation of rhodamine B as a model pollutant.A higher photocatalytic activity was observed in the WO3 sample with the m-WO3/h-WO3junction as compared with the sample with only m-WO3.The improvement of photocatalytic activity can be attributed to the reduction of the electron-hole recombination rate owing to the formation of the phase junction,whose presence has been confirmed by HRTEM and photoluminescence spectra. 展开更多
关键词 Tungsten oxide Phase junction Thermal decomposition method PHOTOCATALYSIS Rhodamine B
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Preparation of Al-doped ZnO sputter target by hot pressing 被引量:6
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作者 王星明 白雪 +4 位作者 段华英 石志霞 孙静 卢世刚 黄松涛 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第7期1550-1556,共7页
Al-doped ZnO (AZO) target was prepared by hot pressing using ZnO and Al2O3 powder in mass ratio of 98:2.The effects of hot pressing conditions including temperature,pressure and preserving time on relative density ... Al-doped ZnO (AZO) target was prepared by hot pressing using ZnO and Al2O3 powder in mass ratio of 98:2.The effects of hot pressing conditions including temperature,pressure and preserving time on relative density were investigated.Pore evolution and phase structure change during densification process were studied.The results show that AZO target with super high relative density of 99% was prepared by two-stage hot pressing method under pressure of 35MPa,temperature of 1 050℃ and 1 150℃ with preserving time of 1 h,respectively.At temperature around 1 050℃,the number of isolated pore wasminimum.At temperature lower than 900℃,there existed Al2O3 phase.At temperature higher than 1 000℃,ZnAl2O4 phase was generated and its content was increased with temperature increasing.Hot pressing method had the advantage over pressureless sintering that the content of ZnAl2O4 was lower and sintering temperature could be also lower.With increasing the hot pressing temperature and preserving time,the electric resistivity of AZO target decreased greatly.A low resistivity of 3 10-3 cm was achieved under the temperature of 1 100℃,pressure of 35MPa and preserving time of 10 h. 展开更多
关键词 aluminum-doped ZnO (AZO) sputter target hot pressing PORE phase structure
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Hydrogen storage kinetics of nanocrystalline and amorphous Cu-Nd-added Mg_2Ni-type alloys 被引量:7
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作者 张羊换 许胜 +3 位作者 翟亭亭 杨泰 袁泽明 赵栋梁 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第11期3524-3533,共10页
The(Mg24Ni10Cu2)100-x Nd x(x=0, 5, 10, 15, 20) alloys with nanocrystalline and amorphous structures were prepared by melt spinning technology. The structures of the as-cast and spun alloys were characterized by X-ray ... The(Mg24Ni10Cu2)100-x Nd x(x=0, 5, 10, 15, 20) alloys with nanocrystalline and amorphous structures were prepared by melt spinning technology. The structures of the as-cast and spun alloys were characterized by X-ray diffraction(XRD) and high resolution transmission electron microscopy(HRTEM). The effects of Nd content and spinning rate on the structures and hydrogen storage kinetics of the alloys were investigated. The results show that the as-spun Nd-free alloy displays an entire nanocrystalline structure, whereas the as-spun Nd-added alloys hold nanocrystalline and amorphous structures, suggesting that the addition of Nd facilitates the glass forming of the alloys. Both the Nd-addition and the melt spinning significantly improve the gaseous and electrochemical hydrogen storage kinetics of the alloys. The addition of Nd and melt spinning enhance the diffusion ability of hydrogen atoms in the alloy, but both of them impair the charge-transfer reaction on the surface of the alloy electrode, which makes the high rate discharge ability(HRD) of the alloy electrode first mount up and then go down with the growing Nd content and spinning rate. 展开更多
关键词 hydrogen storage Nd-addition melt spinning phase structures KINETICS
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Effects of stoichiometric ratio La/Mg on structures and electrochemical performances of as-cast and annealed La-Mg-Ni-based A_2B_7-type electrode alloys 被引量:3
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作者 张羊换 杨泰 +3 位作者 翟亭亭 袁泽明 张国芳 郭世海 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第6期1968-1977,共10页
In order to investigate the influences of the stoichiometric ratio of La/Mg (increasing La and decreasing Mg on the same mole ratio) on the structure and electrochemical performances of the La-Mg-Ni-based A2B7-type ... In order to investigate the influences of the stoichiometric ratio of La/Mg (increasing La and decreasing Mg on the same mole ratio) on the structure and electrochemical performances of the La-Mg-Ni-based A2B7-type electrode alloy, the as-cast and the annealed ternary Lao.8+xMgo.2_xNi3.5 (x=0-0.05) electrode alloys were prepared. The characterization of electrode alloys by X-ray diffraction (XRD) and scanning electron microscopy (SEM) shows that all the as-cast and the annealed alloys hold two major phases of (La,Mg)2Ni7 and LaNi5 as well as a residual phase of LaNi3. Moreover, the increase of La/Mg ratio brings on a decline of (La,Mg)2Ni7 phase and a rise of LaNi5 and LaNi3 phases. The variation of La/Mg ratio gives rise to an evident change of the electrochemical performances of the alloys. The discharge capacities of the as-cast and the annealed alloys evidently decrease with growing the La/Mg ratio, while the cycle stabilities of the alloys visibly augment under the same condition. Furthermore, the high rate discharge ability (HRD), the electrochemical impedance spectrum (EIS), the Tafel polarization curves, and the potential step measurements all indicate that the electrochemical kinetic properties of the alloy electrodes increase with the La/Mg ratio rising. 展开更多
关键词 hydrogen storage alloy annealing treatment structure electrochemical performance KINETICS
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Effects of microwave sintering temperature and soaking time on microstructure of WC-8Co 被引量:11
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作者 鲍瑞 易健宏 +1 位作者 彭元东 张浩泽 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第2期372-376,共5页
WC-8Co cemented carbide samples were processed via microwave irradiation in a 2.45 GHz, high-power multi-mode microwave cavity. The densification of the compacts and the microstructures of the prepared alloys were stu... WC-8Co cemented carbide samples were processed via microwave irradiation in a 2.45 GHz, high-power multi-mode microwave cavity. The densification of the compacts and the microstructures of the prepared alloys were studied. The results demonstrate that the liquid phase is formed around 1300 ℃ and nearly full densification is obtained at 1450 ℃ for 5 min via microwave irradiation. The microstructures of microwave sintered samples have finer and more uniform WC grains than those of vacuum sintered samples. Besides, the WC grain size and distribution are only decided by the sintering temperature. Holding time has negligible effects on them. No matter how holding time is, the mean grain size is 2.7 pan when the sintering temperature is kept at 1450 ℃. 展开更多
关键词 tungsten carbide microwave sintering cobalt binder MICROSTRUCTURE grain size
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Design and fabrication of sintered wick for miniature cylindrical heat pipe 被引量:4
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作者 蒋乐伦 汤勇 +4 位作者 周伟 蒋琳珍 肖潭 李燕 高金武 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第1期292-301,共10页
Miniature cylindrical metal powder sintered wick heat pipe (sintered heat pipe) is an ideal component with super-high thermal efficiency for high heat flux electronics cooling. The sintering process for sintered wic... Miniature cylindrical metal powder sintered wick heat pipe (sintered heat pipe) is an ideal component with super-high thermal efficiency for high heat flux electronics cooling. The sintering process for sintered wick is important for its quality. The sintering process was optimally designed based on the equation of the heat transfer limit of sintered heat pipe. Four-step sintering process was proposed to fabricate sintered wick. The sintering parameters including sintering temperature, sintering time, sintering atmosphere and sintering position were discussed. The experimental results showed that the proper sintering temperature was 950 ℃ for Cu powder of 159μm and 900 ℃ for Cu powders of 81 and 38 μm, respectively, while the wick thickness was 0.45 mm and sintering time was 3 h. The optimized sintering time was 3 h for 0.45 and 0.6 mm wick thickness and 1 h for 0.75 mm wick thickness, respectively, when copper powder diameter was 159μm and sintering temperature was 950 ℃. Redox reduction reaction between H2 and CuO during sintering could produce segmentation cracks in Cu powders as a second structure. Sintering at vertical position can effectively avoid the generation of gap between wick and the inner wall of pipe. 展开更多
关键词 heat pipe WICK SINTERING POROSITY SHRINKAGE
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Formation of precipitates and recrystallization resistance in Al-Sc-Zr alloys 被引量:10
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作者 贾志宏 Jostein RφYSET +1 位作者 Jan Ketil SOLBERG 刘庆 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第8期1866-1871,共6页
Al-x%Sc-0.11%Zr alloys (x=0, 0.02, 0.05, 0.08, 0.11, 0.15) were produced by a chill cast procedure. The effect of Sc content on the precipitation of Al3(Sc,Zr) during heat treatment at 475 °C for 12 h was stu... Al-x%Sc-0.11%Zr alloys (x=0, 0.02, 0.05, 0.08, 0.11, 0.15) were produced by a chill cast procedure. The effect of Sc content on the precipitation of Al3(Sc,Zr) during heat treatment at 475 °C for 12 h was studied. Nucleation, precipitation and distribution of Al3(Sc,Zr) precipitates were found to be strongly related to the Sc content. With increasing the Sc content, the average radius of the precipitates decreases, while the number density of the precipitates increases, as investigated by transmission electron microscopy (TEM). The distribution of the precipitates becomes more and more homogeneous when the Sc content is increased. The recrystallization resistance of samples that was 90% cold rolled and isothermal annealed for half an hour in the temperature range of 200-600 °C was investigated. The results show that the recrystallization temperature varies from 250 °C for the alloy without Sc to about 600 °C for the alloy containing 0.15% Sc because of the high density of Al3(Sc,Zr) precipitates. 展开更多
关键词 aluminium alloy PRECIPITATE recrystallization resistance
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Phase structure and electrochemical properties of La_(0.7)Ce_(0.3)Ni_(3.75)Mn_(0.35)Al_(0.15)Cu_(0.75-x)Fe_x hydrogen storage alloys 被引量:2
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作者 刘宝忠 李安铭 +2 位作者 范燕平 胡梦娟 张宝庆 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第11期2730-2735,共6页
La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-xFex (x=0-0.20) hydrogen storage alloys were synthesized by induction melting and subsequent annealing treatment, and phase structure and electrochemical characteristics were inves... La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-xFex (x=0-0.20) hydrogen storage alloys were synthesized by induction melting and subsequent annealing treatment, and phase structure and electrochemical characteristics were investigated. All alloys consist of a single LaNi5 phase with CaCu5 structure, and the lattice constant a and the cell volume (V) of the LaNi5 phase increase with increasing x value. The maximum discharge capacity gradually decreases from 319.0 mA?h/g (x=0) to 291.9 mA?h/g (x=0.20) with the increase in x value. The high-rate dischargeability at the discharge current density of 1200 mA/g decreases monotonically from 53.1% (x=0) to 44.2% (x=0.20). The cycling stability increases with increasing x from 0 to 0.20, which is mainly ascribed to the improvement of the pulverization resistance. 展开更多
关键词 hydrogen storage alloy AB5-type hydrogen storage alloys phase structures electrochemical property KINETICS Ni-MH battery LaNi5 phase
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Effect of homogenization treatment on microstructure and mechanical properties of DC cast 7X50 aluminum alloy 被引量:10
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作者 丛福官 赵刚 +2 位作者 姜锋 田昵 李瑞峰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第4期1027-1034,共8页
The evolution of the eutectic structures in the as-cast and homogenized 7X50 aluminum alloys was studied by scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive spectrometer(EDS)... The evolution of the eutectic structures in the as-cast and homogenized 7X50 aluminum alloys was studied by scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive spectrometer(EDS), differential scanning calorimetry(DSC), X-ray diffraction(XRD) and tensile test. The results show that the main phases are S(Al2CuMg), T(Al2Mg3Zn3) and Mg Zn2, with a small amount of Al7Cu2 Fe and Al3 Zr in the as-cast 7X50 alloy. The volume fraction of the dendritic-network structure and residual phase decreases gradually during the homogenization. After homogenization at 470 °C for 24 h and then 482 °C for 12 h, the T(Al2Mg3Zn3) phase disappears and minimal S(Al2CuMg) phase remains, while almost no change has happened for Al7Cu2 Fe. There is a strong endothermic peak at 477.8 °C in the DSC curve of as-cast alloy. A new endothermic peak appears at 487.5 °C for the sample homogenized at 470 °C for 1 h. However, this endothermic peak disappears after being homogenized at 482 °C for 24 h. The T(Al2Mg3Zn3) phase cannot be observed by XRD, which is consistent with that T phase is the associated one of S(Al2CuMg) phase and Mg Zn2 phase. The volume fraction of recrystallized grains is substantially less in the plate with pre-homogenization treatment. The strength and fracture toughness of the plate with pre-homogenization treatment are about 15 MPa and 3.3 MPa·m1/2 higher than those of the material with conventional homogenization treatment. 展开更多
关键词 7X50 aluminum alloy microstructural evolution HOMOGENIZATION residual phase RECRYSTALLIZATION
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WC-Ni_3Al-B composites prepared through Ni+Al elemental powder route 被引量:6
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作者 龙坚战 张忠健 +4 位作者 徐涛 彭文 魏修宇 陆必志 李仁琼 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第4期847-852,共6页
In order to develop the liquid phase sintering process of WC-Ni3Al-B composites,the preparation process of WC+Ni3Al prealloyed powder by reaction synthesis of carbonyl Ni,analytical purity Al and coarse WC powders wa... In order to develop the liquid phase sintering process of WC-Ni3Al-B composites,the preparation process of WC+Ni3Al prealloyed powder by reaction synthesis of carbonyl Ni,analytical purity Al and coarse WC powders was investigated.DSC and XRD were adopted to study the procedure of phase transformation for the 3Ni+Al and 70%WC+(3Ni+Al) mixed powders in temperature ranges of 550-1200 °C and 25-1400 °C,respectively.The results demonstrate that the formation mechanism of Ni3Al depends on the reaction temperature.Besides WC phase,there exist Ni2Al3,NiAl and Ni3Al intermetallics in the powder mixture after heat treatment at 200-660 °C,while only NiAl and Ni3Al exist at 660-1100 °C.Homogeneous WC+Ni3Al powder mixture can be obtained in the temperature range of 1100-1200 °C.The WC-30%(Ni3Al-B) composites prepared from the mixed powders by conventional powder metallurgy technology show nearly full density and the shape of WC is round.WC-30%(Ni3Al-B) composites exhibit higher hardness of 9.7 GPa,inferior bending strength of 1800 MPa and similar fracture toughness of 18 MPa-m1/2 compared with commercial cemented carbides YGR45(WC-30%(Co-Ni-Cr)). 展开更多
关键词 WC-Ni3Al-B composites Ni3Al intermetallic liquid phase sintering mechanical properties
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First-principles study of phase stability and electronic properties of RhZr 被引量:2
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作者 胡洁琼 潘勇 谢明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第10期2301-2305,共5页
First-principles calculations were carried out to investigate the structural stabilities and electronic properties of RhZr.The plane wave based pseudopotential method was used,in which both the local density approxima... First-principles calculations were carried out to investigate the structural stabilities and electronic properties of RhZr.The plane wave based pseudopotential method was used,in which both the local density approximation(LDA) and the generalized gradient approximation(GGA) implanted in the CASTEP code were employed.The internal positions of atoms in the unit cell were optimized and the ground state properties such as lattice parameter,density of state,cohesive energies and enthalpies of formation of ortho-RhZr and cubic-RhZr were calculated.The calculation results indicate that ortho-RhZr can form more easily than cubic-RhZr and the ortho-RhZr is more stable than cubic-RhZr.The density of states(DOS) reveals that the strong bonding in the Rh-Zr and Rh-Rh or Zr-Zr interaction chains accounts for the structural stability of ortho-RhZr and the hybridization between Rh-4d states and Zr-4d states is strong. 展开更多
关键词 RhZr FIRST-PRINCIPLES phase stability electronic properties
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