作者： Fan, Xiaoyi;Si, Jiayong;Xu, Mengjie;Li, Guihua;Tang, Jiamin;...

期刊： Ceramics International,2021年47(9):12056-12065 ISSN：0272-8842

通讯作者： Si, Jiayong(sjy98106@163.com);Cai, Gemei(caigemei@csu.edu.cn)

作者机构： [Si, Jiayong; Fan, Xiaoyi; Xu, Mengjie; Tang, Jiamin] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Cai, Gemei; Li, Guihua] Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

通讯机构： [Jiayong Si] C;[Gemei Cai] S;College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, Hunan, 410004, People’s Republic of China<&wdkj&>School of Materials Science and Engineering, Central South University, Changsha, Hunan, 410083, People’s Republic of China

关键词： Ca9La(PO4)7;White-emitting phosphor;Luminescence properties;Energy transfer;Thermal stability

摘要： The development of novel single-component white-emitting phosphors with high thermal stability is essential for improving the illumination quality of white light-emitting diodes. In this work, we synthesized a series of Ce3+, Tb3+, Mn2+ single- and multiple-doped Ca9La(PO4)7 (CLPO) phosphors with β-Ca3(PO4)2-type structure by the simple high-temperature solid-state reaction. The crystallization behavior, crystal structure, surface morphology, photoluminescence performance, decay lifetime and thermal stability were systematically investigated. The PL spectra and decay curves have evidenced the efficient energy transfer from Ce3+ to Tb3+ and from Ce3+ to Mn2+ in the CLPO host, and corresponding energy transfer efficiency reaches 41.8% and 54.1%, respectively. The energy transfer process of Ce3+→Tb3+ and Ce3+→Mn2+ can be deduced to the resonant type via dipole-dipole and dipole-quadrupole interaction mechanism, and corresponding critical distance were determined to be 12.23 and 14.4 Å, respectively. Based on the efficient energy transfer, the white light emission can be successfully achieved in the single-component CLPO:0.15Ce3+, 0.10Tb3+, 0.04Mn2+ phosphor, which owns CIE chromaticity coordinates of (0.3245, 0.3347), CCT of 5878 K, internal and external quantum efficiency of 84.51% and 69.32%. Especially, compared with the emission intensity at 25 °C, it still remains 98.5% at 150 °C and 92.0% at 300 °C. Based on these results, the single-component white light emission phosphor CLPO:0.15Ce3+, 0.10Tb3+, 0.04Mn2+ is a potential candidate for UV-converted white LEDs. © 2021 Elsevier Ltd and Techna Group S.r.l.

语种： 英文

作者： 刘松浩;司家勇;陈龙;徐梦杰

期刊： 材料导报,2020年34(20):20123-20129 ISSN：1005-023X

作者机构： 中南林业科技大学机电工程学院, 长沙, 410004;[陈龙; 徐梦杰; 司家勇; 刘松浩] 中南林业科技大学

关键词： FGH4096合金;高应变速率;热压缩;本构模型;热加工图

摘要： 在变形温度为1 020~1 140 ℃、应变速率为0.001~10 s~(-1)的条件下,采用热压缩实验研究了热等静压态FGH4096合金的热变形行为并建立了热加工图。在应变速率为0.001~1.0 s~(-1)时,流变应力在达到峰值后开始减小。当应变速率为10 s~(-1)时,合金的的真应力-真应变曲线剧烈下降,这与试样开裂有关。随着变形温度的降低或应变速率的提高,合金的流变应力增大。当应变速率在1.0 s~(-1)以上时,由于流变应力迅速减小后又增大,合金的真应力-真应变曲线出现了双峰形态,这与高应变速率下滑移系开动和位错转变有关。真应变为0.3的热加工图中含有两个明显的动态再结晶区域,耗散率峰值位置分别为:( 1)变形温度1 040 ℃、应变速率0.002 s~(-1),耗散率62%;( 2)变形温度1 120 ℃、应变速率0.001 s~(-1),耗散率53%。当真应变为0.4时,该合金在变形温度1 050~1 105 ℃、应变速率高于0.2 s~(-1)时存在流动失稳。

语种： 中文

作者： 刘松浩;司家勇;陈龙

期刊： 中国有色金属学报,2020年30(6):1317-1328 ISSN：1004-0609

通讯作者： Si, J.-Y.

作者机构： 中南林业科技大学机电工程学院,长沙410004;[陈龙; 司家勇; 刘松浩] 中南林业科技大学

通讯机构： College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, China

关键词： FGH4096合金;挤压态;热压缩;过固溶热处理;临界晶粒长大

摘要： 基于挤压态FGH4096合金双圆锥台试样热压缩变形及过固溶热处理试验,结合DEFORM有限元软件数值模拟,确定试样中各等效应变范围内临界晶粒长大分布规律,研究热加工工艺对挤压态FGH4096合金临界晶粒长大的影响。结果表明:在温度980~1060℃、应变速率0.003~0.03s~(-1)条件下,双圆锥台试样热变形后再经过固溶热处理,合金临界晶粒长大的窗口条件从低温低应变速率向高温高应变速率转变,其中(980℃、0.03s~(-1))、(1060℃、0.003s~(-1))条件下可以避免出现临界晶粒长大,并获得均匀晶粒组织。当变形温度为980℃时,随着应变速率的增加,异常晶粒长大程度减小,且合金临界晶粒长大位置的临界等效应变数值降低;当应变速率为0.03s~(-1)时,随着变形温度的升高,异常晶粒长大程度增大,且试样发生临界晶粒长大的等效应变区域扩大。

语种： 中文

作者： Si, Jiayong*;Yang, Nian;Xu, Mengjie;Li, Guihua;Cai, Gemei*;...

期刊： Ceramics International,2020年46(18):28373-28381 ISSN：0272-8842

通讯作者： Si, Jiayong;Cai, Gemei

作者机构： [Si, Jiayong; Xu, Mengjie] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Cai, Gemei; Yang, Nian; Li, Guihua] Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Yi, Wei] MANA, Nano Elect Device Mat Grp, Namiki 1-1, Tsukuba, Ibaraki 3050044, Japan.;[Zhang, Jing] Southwest Petr Univ, Sch New Energy & Mat, Chengdu 610500, Sichuan, Peoples R China.

通讯机构： [Si, Jiayong; Cai, Gemei] C;Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

关键词： LaNbO4;Crystal structure;Luminescence;Cathodoluminescence;Energy transfer

摘要： The pure Sm3+/Er3+ doped host-sensitized LaNbO4 phosphors were synthesized and characterized. By virtue of the Rietveld Method, crystal structure of LaNbO4:Sm3+/Er3+ were refined, with the occupation of dopants determined. The luminescence properties of Sm3+/Er3+ doped LaNbO4 phosphors were carefully measured and analyzed by diffuse reflectance spectra, ultraviolet and cathodoluminescence (CL). The energy transfer was recognized between host and doped Sm3+/Er3+ ions based on the luminescence spectra and decay lifetimes, which is dominated by electric multipolar interaction. Further, the calculated critical distance is 23.71 and 23.08 Å for Sm3+ and Er3+ doped, respectively. Moreover, the temperature sensitivity of Sm3+/Er3+ doped LaNbO4 was evaluated at the temperature ranging from 23 K to 298 K. By adjusting the concentration of Sm3+/Er3+ ions, the emission colors of LaNbO4:Sm3+ and LaNbO4:Er3+ are varied from blue to pink and from blue to cyan. These results indicate that LaNbO4:Sm3+/Er3+ phosphors can be applied in the plasma display panels (PDP) and general lighting. © 2020 Elsevier Ltd and Techna Group S.r.l.

语种： 英文

作者： Xu, M. J.;Si, J. Y.*;Li, G. H.;Liu, Y. J.;Cai, G. M.*;...

期刊： Journal of Luminescence,2020年221:117115 ISSN：0022-2313

通讯作者： Si, J. Y.;Cai, G. M.

作者机构： [Si, J. Y.; Xu, M. J.] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Liu, Y. J.; Cai, G. M.; Li, G. H.] Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Zhang, J.] Southwest Petr Univ, Sch Mat Sci & Engn, Chengdu 610500, Sichuan, Peoples R China.

通讯机构： [Si, J. Y.; Cai, G. M.] C;Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

关键词： Barium compounds;Crystal structure;Energy transfer;Luminescence of inorganic solids;Phosphors;Plasma display devices;Rietveld refinement;Ultraviolet spectroscopy;Dipole dipole interactions;Efficient energy transfer;Energy transfer mechanisms;High temperature solid state methods;KBaIn2(PO4)3;Luminescence properties;Powder X ray diffraction;Tunable emissions;Terbium compounds

摘要： To develop the new luminescence materials, a series of Eu3+/Tb3+ doped novel KBaIn2(PO4)3 (KBIP) phosphors were successfully synthesized using the high-temperature solid-state method. The powder X-ray diffraction data and Rietveld refinement results showed that the phosphors are pure phases. The UV excited luminescence properties of the Eu3+/Tb3+ doped KBIP phosphors were investigated. Based on the UV spectra and decay curves, the efficient energy transfer from Tb3+ to Eu3+ in KBIP phosphor was recognized. In addition, the energy-transfer mechanism is ascribed to the resonant type via a non-radiative dipole-dipole interaction, with the transfer efficiency as high as 79.8%. At 150 °C, the overall emission intensity still maintains 68.5% of that at room temperature. The tunable color emission from green to red can be obtained by adjusting the concentration of doped Tb3+ and Eu3+ ions. The results indicate that the KBaIn2(PO4)3 based phosphors are potential candidate for applications in the plasma display panels (PDP) and lighting fields. © 2020 Elsevier B.V.

语种： 英文

作者： Si, Jiayong*;Liu, Lihong;Liang, Qifeng;Yi, Wei;Cai, Gemei;...

期刊： Journal of Alloys and Compounds,2020年831:154791 ISSN：0925-8388

通讯作者： Si, Jiayong;Xie, Rong-Jun

作者机构： [Si, Jiayong] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Si, Jiayong; Hirosaki, Naoto; Liu, Lihong; Takeda, Takashi] Natl Inst Mat Sci, Sialon Grp, Namiki1-1, Tsukuba, Ibaraki 3050044, Japan.;[Liang, Qifeng] Shaoxing Univ, Dept Phys, Shaoxin 312000, Zhejiang, Peoples R China.;[Yi, Wei] MANA, Nano Elect Device Mat Grp, Namiki 1-1, Tsukuba, Ibaraki 3050044, Japan.;[Cai, Gemei] Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

通讯机构： [Si, Jiayong] C;[Xie, Rong-Jun] X;Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;Xiamen Univ, Coll Mat, Xiamen 361005, Fujian, Peoples R China.

关键词： Aluminum compounds;Blue shift;Calcium compounds;Cerium compounds;Efficiency;Electronic structure;Light emission;Lighting;Phosphors;Professional aspects;Quantum efficiency;Silicon;Silicon compounds;Thermodynamic stability;Tuning;Broadband emission;Color rendering index;Color rendering properties;Color tuning;External quantum efficiency;Local coordination structures;White LED;White lightemitting diodes (WLEDs);Nitrogen compounds

摘要： Ce3+ doped CaAlSiN3 is a promising broadband orange phosphor that can be applied in white light-emitting diodes (wLEDs) solid state lighting for general illumination. However, its emission color and quantum efficiency are not good enough to achieve high color rendering properties and luminous efficacy of wLEDs. In this work, we proposed to realize the spectral tuning and property enhancement of CaAlSiN3:Ce3+ by bandgap engineering via the cationic substitution of Ca by Sr. The relationship between photoluminescence and local coordination structure as well as electronic structure were revealed. The substitution led to a blue-shift in emission maximum by 13 nm (from 595 to 582 nm) and a highest external quantum efficiency of 55% (enhanced by 10%). This broadband yellow phosphor enabled to produce wLEDs with a color rendering index of 83.3, luminous efficacy of 114.6 l m/W and a color temperature of 4604 K. © 2020 Elsevier B.V.

语种： 英文

作者： Song, Siyuan;Si, Jiayong*;Zhang, Jing;Cai, Gemei*

期刊： RSC Advances,2019年9(2):1029-1035 ISSN：2046-2069

通讯作者： Si, Jiayong;Cai, Gemei

作者机构： [Si, Jiayong; Song, Siyuan] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Zhang, Jing; Cai, Gemei] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

通讯机构： [Si, Jiayong; Cai, Gemei] C;Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

摘要： The borate Ba 3 InB 9 O 18 (BIBO) is a promising host material for phosphors. A series of Tb 3+ and Eu 3+ codoped Ba 3 InB 9 O 18 phosphors were synthesized. Based on the Rietveld method, structure refinement of the codoped BIBO phosphor was carried out. Then, the luminescence properties of BIBO:Tb 3+ , Eu 3+ phosphors were extensively investigated under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation. The measured PL spectra and decay times evidenced that energy transfer occurs between the Tb 3+ and Eu 3+ ions. The energy-transfer mechanism from Tb 3+ to Eu 3+ in Ba 3 InB 9 O 18 is dominated by electric multipolar interactions, with the critical distance calculated to be 10.97 Å. The temperature sensitivity of the Tb 3+ and Eu 3+ codoped sample under VUV was also investigated at the low temperature range from 25 K to 298 K. The emission color could be tuned from green to the red region by adjusting the concentration of codoped ions. The results indicate that the BIBO-based phosphors are valuable candidates for applications in the display and lighting fields. © The Royal Society of Chemistry.

语种： 英文

作者： Si, Jiayong;Wang, Le*;Liu, Lihong;Yi, Wei;Cai, Gemei;...

期刊： Journal of Materials Chemistry C,2019年7(3):733-742 ISSN：2050-7526

通讯作者： Wang, Le;Xie, Rong-Jun

作者机构： [Si, Jiayong] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Si, Jiayong; Hirosaki, Naoto; Funahashi, Shiro; Liu, Lihong; Takeda, Takashi] Natl Inst Mat Sci, Sialon Grp, Namiki1-1, Tsukuba, Ibaraki 3050044, Japan.;[Wang, Le] China Jiliang Univ, Coll Opt & Elect Technol, Hangzhou 310018, Zhejiang, Peoples R China.;[Yi, Wei] MANA, Nano Elect Device Mat Grp, Namiki 1-1, Tsukuba, Ibaraki 3050044, Japan.;[Cai, Gemei] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

通讯机构： [Wang, Le] C;[Xie, Rong-Jun] X;China Jiliang Univ, Coll Opt & Elect Technol, Hangzhou 310018, Zhejiang, Peoples R China.;Xiamen Univ, Coll Mat, Xiamen 316005, Fujian, Peoples R China.

关键词： Aluminum;Energy transfer;Ions;Liquid crystal displays;Luminescence;Nuclear magnetic resonance spectroscopy;Phosphors;Rietveld refinement;Sintering;Energy transfer mechanisms;Energy transfer process;External quantum efficiency;Gas-pressure sintering;Green-emitting phosphors;Internal quantum efficiency;Luminescence intensity;Quadrupole interactions;Quantum efficiency

摘要： Mn 2+ doped γ-AlON is an interesting narrow-band green emitting phosphor which can be used in wide color gamut white LED backlights for liquid crystal displays (LCDs). However, the spin-forbidden transition of 3d 5 in Mn 2+ results in a quite low absorption efficiency, γ-AlON:Mn 2+ thus has a small external quantum efficiency. Besides Eu 2+ ,Ce 3+ is another promising sensitizer and is expected to improve the emission of Mn 2+ through a distinctive energy transfer process. In this work, a series of Ce 3+ -Mn 2+ codoped γ-AlON phosphors were synthesized by gas pressure sintering at 1800 °C for 2 h under 0.5 MPa nitrogen gas pressure. The Rietveld refinement analysis shows that Al atoms occupy both 8a and 16d sites, while codoped Ce 3+ and Mn 2+ ions substitute the 8a Al atoms only in the tetrahedral sites. The 27 Al solid state NMR spectrum further confirms the chemical shifts of AlO 4 and AlO 6 sites at 71.4 and 0 ppm, respectively. The measured PL, CL and decay times have evidenced that a brisk energy transfer occurs between the Ce 3+ and Mn 2+ ions. The energy transfer mechanism from Ce 3+ to Mn 2+ in γ-AlON is a quadrupole-quadrupole interaction and the critical distance is calculated to be 15.97 Å. Upon UV or blue light excitation, the codoped γ-AlON phosphor has higher luminescence intensity, quantum efficiency and thermal stability than the Mn 2+ -doped γ-AlON due to the energy transfer and low total concentration of Ce 3+ and Mn 2+ ions. Meanwhile, the absorption, internal quantum efficiency and external quantum efficiency are raised to 60.2%, 61.3% and 36.9% upon 310 nm excitation. © 2019 The Royal Society of Chemistry.

语种： 英文

作者： Zhang, G. X.;Zhang, J.;Liu, Y. J.;Si, J. Y.;Tao, X. M.;...

期刊： Journal of Alloys and Compounds,2019年797:775-785 ISSN：0925-8388

通讯作者： Cai, G. M.

作者机构： [Liu, Y. J.; Zhang, G. X.; Cai, G. M.; Zhang, J.] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Si, J. Y.] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Tao, X. M.] Guangxi Univ, Coll Phys Sci & Technol, Nanning 530004, Peoples R China.

通讯机构： [Cai, G. M.] C;Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

关键词： Barium compounds;Electronic structure;Energy gap;Indium compounds;Luminescence;Luminescence of inorganic solids;Magnesium compounds;Phosphors;Sound insulating materials;Ba3In4(PO4)6;Crystal structure determination;High melting point;Langbeinite structure;Luminescence properties;Multicolor tunable;Thermal Performance;UV-vis diffuse reflectance spectra;Crystal structure

摘要： A new phosphate Ba3In4(PO4)6 has been discovered in the exploration of novel host materials for color-tunable phosphors in BaO-In2O3-P2O5 system. The crystal-structure determination using powder XRD data reveals it belongs to the cubic langbeinite structure type (S.G. P213), unlike Mg3In4(PO4)6 crystallizing the triclinic system (S.G. P1¯). The existence of PO4 has been verified by IR spectra of the title compound. DTA and experimental indicate that this new phosphate has a high melting point of ∼1293 °C. Combined with calculated electronic structure and experimental UV-Vis diffuse reflectance spectrum, it has a wide direct energy band gap which is favorable for host materials. The site symmetry of Eu3+ ions and the cross relaxation of Tb3+ ions in this matrix have been clarified according to their luminescence properties. Red-pink-green tunable emission can be realized adjusting the Eu3+ and Tb3+ contents. The quantum yields of representative phosphors under the excitation of 370–392 nm ultraviolet radiation have been measured and discussed. The PL intensity of Ba3In4(PO4)6: 0.02Eu3+, 0.015 Tb3+ phosphor at 423 K of is about 67% of that at 298 K. Present results indicate that the Ba3In4(PO4)6-based phosphors are valuable for the multicolor and stable thermal performance in the display and lighting fields. © 2019 Elsevier B.V.

语种： 英文

作者： 陈龙;司家勇;刘松浩;廖凯

期刊： 材料导报,2019年33(12):2047-2054 ISSN：1005-023X

通讯作者： Si, Jiayong(sjy98106@163.com)

作者机构： [陈龙; 司家勇; 刘松浩; 廖凯] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha;410004, China;[陈龙; 司家勇; 刘松浩; 廖凯] 410004, China

通讯机构： College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, China

关键词： FGH4096合金;挤压态;热压缩;本构模型;热加工图

摘要： 为了获得挤压态FGH4096合金的热加工最佳工艺参数,利用Gleeble 3180D热模拟实验机对热挤压后的FGH4096合金进行了高温压缩实验,研究了其在变形温度1 020～1 140℃、应变速率0.001～1.0 s-1、压下量50%条件下的高温变形行为,分析了应变速率和变形温度对流变应力的影响,并基于双曲正弦模型与动态材料模型建立相应的本构方程和热加工图。结果表明,该合金的热变形激活能为1 128.79 kJ/mol;优化的热加工工艺参数范围为变形温度1 049～1 080℃、应变速率0.005～0.013 s-1,在该区域内合金的能量耗散率峰值为64%。通过微观组织分析发现,此区域内金相组织发生完全动态再结晶,合金的晶粒细小且均匀。

语种： 中文

作者： 司家勇;李立君;张立强;杜俊鸿;刘朋

期刊： 农业工程与装备,2019年(3):65-68 ISSN：2096-8736

作者机构： 中南林业科技大学机电工程学院;[刘朋; 杜俊鸿] 湖南晓光汽车模具有限公司;[张立强; 司家勇; 李立君] 中南林业科技大学

关键词： 林业类院校;机械工程领域;校企合作;研究生培养模式

摘要： 鉴于湖南省经济发展状况,结合中南林业科技大学和省内企业发展的基本情况,本文选择湖南晓光汽车模具有限公司作为校企合作研究生培养试点企业,提出一种适用于林业高校机械工程方向研究生培养现状的校企联合培养模式,这种模式是结合高校主导和企业主导两种校企联合培养模式的优势与不足提出的一种改良模式,以高校为主导的渐进式联合培养模式,不仅可以帮助生产企业解决产品加工中的技术难题,也可以培养机械工程领域研究生的解决实际问题的能力,构建特色鲜明的林业院校机械工程领域***应用型人才培养模式。

语种： 中文

作者： Si, J. Y.*;Song, S. Y.;Liu, N.;Cai, G. M.*;Su, L. M.

期刊： Journal of Luminescence,2018年198:10-18 ISSN：0022-2313

通讯作者： Si, J. Y.;Cai, G. M.

作者机构： [Song, S. Y.; Si, J. Y.; Liu, N.] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Su, L. M.; Cai, G. M.] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

通讯机构： [Si, J. Y.; Cai, G. M.] C;Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

关键词： Doping (additives);Dysprosium alloys;Emission spectroscopy;Light emission;Luminescence;Luminescence of inorganic solids;Magnesium alloys;Magnesium compounds;Niobium alloys;Phosphors;Photoluminescence;Solid state reactions;Thulium compounds;X ray diffraction;Characteristic emission;Luminescence properties;Luminescent material;Measurement of temperature;Photoluminescence excitation;Powder X ray diffraction;Temperature quenching;VUV excitation;Niobium compounds

摘要： A series of undoped, Dy3+ and Tm3+ singly-doped, co-doped MgNb2O6 phosphors were prepared by solid-state reaction. Powder X-ray diffraction (XRD), photoluminescence excitation (PLE) and emission (PL) spectrum under UV and VUV excitation, decay lifetimes and CIE chromaticity coordinate were employed to explore the luminescence properties of synthesized phosphors. MgNb2O6 host exhibits a broad emission band from about 350 to 650 nm centered around 451 nm under the UV excitation of 275 nm originating from the NbO6 octahedral groups. Its photoluminescence presents the temperature quenching behavior under VUV excitation. The yellow phosphor MgNb2O6:Dy3+ and blue phosphor MgNb2O6:Tm3+ show the dominant emission peak at 583 nm (4F9/2-6H13/2) upon 275 nm excitation and at 484 nm (1G4-3H6) upon 274 nm, respectively. The Dy3+ and Tm3+ co-doped MgNb2O6 phosphors exhibit tunable colors varying from yellow to warm-white with the emission peak at 583 nm (4F9/2-6H13/2) as concentration of Tm3+ increased. With the increasing concentration of dopant ions, the value of average decay times (t) of characteristic emission of activators monotonously decreases. The stability of representative MNO:0.045Dy3+, 0.02Tm3+ phosphor was investigated base on measurement of temperature-dependent emission spectra. Considering the easy synthesis and special luminescence properties of MgNb2O6-based phosphors, it is extraordinarily meaningful to study for luminescent materials as a fundamental research. © 2018 Elsevier B.V.

语种： 英文

作者： 肖敏;罗迎社;司家勇;刘秀波

期刊： 材料导报,2018年32(2):676-680 ISSN：1005-023X

通讯作者： Luo, Yingshe(lys0258@vip.sina.com)

作者机构： [罗迎社; 刘秀波; 肖敏] Institute of Rheological Mechanics and Materials Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[刘秀波; 罗迎社] Hunan Province Key Laboratory of Engineering Rheology, Central South University of Forestry and Technology, Changsha, 410004, China;[司家勇] School of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, 410004, China

通讯机构： [Luo, Y.] I;Institute of Rheological Mechanics and Materials Engineering, China

关键词： 疲劳损伤演化律;热活化;应变速率;应力幅

摘要： 由损伤力学理论可知,疲劳是由材料内部的损伤演化导致的,但其损伤演化的机理并不清楚。为此,我们将高分子物理中断裂的分子理论推广应用于金属的疲劳损伤,认为金属的断裂是一个松驰过程,宏观断裂是微观原子键断裂热活化的结果。以Q235钢为例,在CMT5105万能电子试验机上进行拉压非对称循环疲劳试验。从原子键离解的视角出发并结合试验数据,讨论并推算诸多因素影响下匀、变速加载时非对称循环疲劳损伤演化律的具体形式。再将速率作为重点考虑因素提出了新的疲劳损伤演化律,分别讨论了匀、变速情况下损伤演化律的基本形式,并对速率相关参数因子进行了修正。结果表明,新的疲劳损伤演化律形式简单、参数少、应用广泛且与试验结果贴合较好。

语种： 中文

作者： Cai, G. M.*;Yang, N.;Liu, H. X.;Si, J. Y.;Zhang, Y. Q.

期刊： Journal of Luminescence,2017年187:211-220 ISSN：0022-2313

通讯作者： Cai, G. M.

作者机构： [Zhang, Y. Q.; Liu, H. X.; Cai, G. M.; Yang, N.] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Si, J. Y.] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.

通讯机构： [Cai, G. M.] C;Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

关键词： Color;Energy transfer;Europium;Light emission;Phosphors;Photoluminescence;Solid state reactions;Color tunable;Concentration quenching;Doping concentration;Rare-earth activators;Solid state reaction method;Structure refinements;Visible photoluminescence;White light emitting diodes;Light emitting diodes

摘要： Novel single-phased white-light-emitting and color tunable LiSrBO3:Dy3+, Tm3+, Eu3+ phosphors were synthesized by solid-state reaction method. Their crystal structures were refined by the Rietveld method using Fullprof_suite program on the basis of powder diffraction data. And their luminescent properties were characterized mainly by ultraviolet (UV) visible photoluminescence excitation (PLE), photoluminescence (PL), and Decay lifetime. The energy transfer among activators in the LiSrBO3 host has been investigated. The chromaticity diagram shows that the Dy3+, Tm3+ co-doped LiSrBO3 phosphors could emit white light and the color was tunable from cold white to warm white by Eu3+ co-activated. The excitation spectra indicate that these phosphors can be effectively excited by ultraviolet 350–400nm, matching well with the dominant emission band of a light-emitting-diode (LED) chip. Rare-earth activators were determined to be completely dissolved into the host lattice and occupied the 4e sites deviated from an inversion center by virtue of XRD, structure refinement and photoluminescence features. Concentration quenching of phosphors LSBO: Na+, Tm3+ occurs at the doping concentration x=0.03. According to their decay curves, the calculated lifetime of LSBO:0.005Dy3+, 0.005Tm3+, LSBO:0.01Dy3+, 0.005Tm3+, and LSBO:0.015Dy3+, 0.005Tm3+ phosphors are 0.99 ms, 0.986 ms, and 0.96 ms, respectively. The present work suggests that these novel phosphors may have potential applications for white LEDs. © 2017 Elsevier B.V.

语种： 英文

作者： 司家勇;陈龙;廖晓航;刘娜;钟利萍

期刊： 机械工程材料,2017年41(4):6-10 ISSN：1000-3738

作者机构： 中南林业科技大学机电工程学院, 粉末冶金国家重点实验室, 长沙, 410004;中南林业科技大学机电工程学院, 长沙, 410004;[司家勇] 中南林业科技大学机电工程学院, 粉末冶金国家重点实验室, 长沙, 410004;[陈龙; 廖晓航; 刘娜; 钟利萍] 中南林业科技大学机电工程学院, 长沙, 410004

关键词： GH4169合金;DP处理;δ相;热变形;动态再结晶

摘要： 对DP处理后的GH4169合金在变形温度900~1 060℃、应变速率0.001~0.500s~(-1)下进行了热压缩变形试验,研究了变形温度、应变速率和应变量对合金显微组织、δ相形貌以及δ相演变的影响,分析了组织演变机制。结果表明:DP处理后合金的显微组织中分布有大量片层状/长针状δ相,在高温压缩变形过程中变形断裂和溶解断裂的综合作用下,随应变量的增加,δ相发生弯曲、扭折直至球化;随着变形温度的升高或应变速率的降低,δ相含量逐渐减少,合金动态再结晶晶粒尺寸和动态再结晶体积分数逐渐增大。

语种： 中文

作者： Si, J. Y.*;Liu, N.;Song, S. Y.;Cai, G. M.*;Yang, N.;...

期刊： Journal of Alloys and Compounds,2017年719:171-181 ISSN：0925-8388

通讯作者： Si, J. Y.;Cai, G. M.

作者机构： [Song, S. Y.; Si, J. Y.; Liu, N.; Li, Z.] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Cai, G. M.; Yang, N.] Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

通讯机构： [Si, J. Y.; Cai, G. M.] C;Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;Cent S Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.

关键词： Citrus fruits;Color;Europium;Light;Lithium;Luminescence;Luminescence of inorganic solids;Phosphors;Solid state reactions;X ray diffraction;Chromaticity coordinates;Color tunable;Doping concentration;Luminescence decays;Luminescence properties;Photo-luminescent properties;Powder X ray diffraction;Solid state reaction method;Light emission

摘要： Taking Li3Sc(BO3)2 as host, a series of Eu3+/Tb3+ singly-doped and co-doped phosphors were synthesized through conventional solid-state reaction method. The phase assemblage and purity of as-prepared phosphors were investigated by analyzing their powder X-ray diffraction (XRD) patterns. The VUV-UV excited luminescence properties of a series of Eu3+/Tb3+ doped Li3Sc(BO3)2 phosphors were investigated in detail, with decay lifetime, chromaticity coordinate and mechanism of the phosphors analyzed. The luminescence decay lifetimes of Eu and Tb are both on a millisecond timescale. The chromaticity coordinates indicate that Li3Sc(BO3)2: 0.01Eu phosphor has a deep reddish orange-red emission and Li3Sc(BO3)2: 0.01Tb phosphor has a bright green emission. The Li3Sc(BO3)2: EuxTby phosphors can generate bright color-tunable green-yellow-red light by changing the doping concentration. With increasing Eu3+ concentration, the emission colors of Li3Sc(BO3)2: 0.01Tb3+, xEu3+ phosphors can be appropriately tuned from green to yellow (λex = 243 nm) and yellow to orange-red (λex = 252 nm), respectively. Under the excitation of near-ultraviolet light 243 and 252 nm, emission colors of Li3Sc(BO3)2: 0.01Eu3+, xTb3+ phosphors can be tuned from yellow-green to green with increasing Tb3+ concentration. © 2017 Elsevier B.V.

语种： 英文

作者： 司家勇;陈龙;廖晓航;李志

期刊： 锻压技术,2017年42(10):180-188 ISSN：1000-3940

作者机构： [司家勇; 陈龙; 廖晓航; 李志] 中南林业科技大学机电工程学院, 湖南, 长沙, 410004

关键词： GH4169合金;DP工艺;本构模型;动态再结晶;δ相

摘要： 通过高温热压缩试验,得到经DP工艺处理的GH4169合金在变形温度为900~1060 ℃、应变速率为0.001~0.5 s~(-1)、压缩量为70%条件下的真应力-真应变曲线,依据流变曲线特征,界定出加工硬化-动态回复和动态流变软化两个阶段,建立了相应的新型高温流变本构模型,同时观察了变形显微组织,进行了定量金相统计分析。结果表明:GH4169合金高温压缩显微组织中的动态再结晶晶粒尺寸随变形温度的升高或应变速率的降低而逐渐增大;δ相含量逐渐减少,在1060 ℃时基本消失。通过引入标准统计参数--相关系数和平均相对误差绝对值,表明预测值和实际试验数值吻合度较高,所建立的本构方程可以用于准确预测经DP工艺处理的GH4169合金热成形过程中的应力值和热成形工艺优化。

语种： 中文

作者： 司家勇;宋思远;廖晓航;黄再旺

期刊： 中国有色金属学报,2016年26(6):1204-1213 ISSN：1004-0609

通讯作者： Si, Jia-Yong(sjy98106@163.com)

作者机构： [司家勇; 宋思远; 廖晓航; 黄再旺] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[司家勇] State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, China

通讯机构： College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, China

关键词： GH4169合金;热加工;高通量测试;数值模拟

摘要： 以经DP工艺处理的GH4169合金为对象,研究热加工高通量双圆锥台试样测试方法,利用数值模拟方法进行双圆锥台试样关键尺寸设计,探讨热加工工艺参数对双圆锥台试样等效应变场分布的影响规律,进行实际试验验证,分析晶界取向差和晶界分布特征。结果表明:摩擦因数对等效应变影响显著,随着摩擦因数的提高,试样中心位置应变量增加,应变梯度加大;随着变形温度的升高和变形速率的减小,试样中心附近的等效应变降低,能促进δ相的溶解和断裂,加快动态再结晶的发生,增大动态再结晶晶粒尺寸;经(1000 ℃,0.01 s~(-1))热变形后高通量双圆锥台试样中心由于动态再结晶导致小角晶界数量很少,统计频率仅为5.6%,外缘变形量低,晶界数量中大角晶界占比高达92.3%,晶内分布有原始孪晶;随着变形温度提高,小角晶界不断减少,孪晶数量有所增加。

语种： 中文

作者： 司家勇;李立君;闵淑辉;仲志刚

期刊： 中国林业教育,2016年34(6):23-26 ISSN：1001-7232

作者机构： 中南林业科技大学机电工程学院;[仲志刚] 湖南晓光汽车模具有限公司;[司家勇; 李立君; 闵淑辉] 中南林业科技大学

关键词： 林业院校;机电类专业;应用型创新人才;培养体系

摘要： 随着我国林业产业的快速发展和生态文明建设的大力推进,对林业院校机电类专业人才培养质量提出了更高的要求,迫切需要具有创新精神和创新能力的高级工程技术人才,因此构建适用于林业产业发展和生态文明建设需求的林业院校机电类专业应用型创新人才培养体系,提升林业机械行业人才培养质量,尤其是培养具有优秀工程素养的应用型创新人才迫在眉睫。借鉴国内外机电和林业行业的人才培养经验,提出了林业机电类专业应用型创新人才培养思路,构建了应用型创新人才培养体系,为我国林业产业和生态文明建设培养了优秀人才,为中国林业产业的发展提供了人才支撑和智力保障。

语种： 中文

作者： 司家勇;李立君;钟利萍;仲志刚

期刊： 农业工程与装备,2016年(3):107-108+118 ISSN：2096-8736

作者机构： 中南林业科技大学机电工程学院;[仲志刚] 湖南晓光汽车模具有限公司;[司家勇; 李立君; 钟利萍] 中南林业科技大学

关键词： 林业院校;机电类专业;应用型创新人才;培养体系

摘要： 文章借鉴国内外机电和林业行业的人才培养经验,理清林业机电类专业应用型创新人才培养思路,更新教育观念,创新人才培养模式,培养具有卓越创新能力的高级工程技术人才,以适应我国林业产业和生态文明建设对优秀人才的要求,为中国林业产业的发展提供人才支撑和智力保障。

语种： 中文