十二烷基磺酸根插层Ni~(2+)-Fe~(3+)/Co~(2+)-Ni~(2+)-Fe~(3+) LDHs及其结构研究

应用水热技术制备了二元Ni2+-Fe3+-CO23- LDHs和三元Co2+-Ni2+-Fe3+-CO32- LDHs,以十二烷基磺酸根离子作为插层客体,通过离子交换反应在酸性溶液中实现了十二烷基磺酸根插层Ni2+-Fe3+ LDHs和Co2+-Ni2+-Fe3+-LDHs。十二烷基磺酸根在Ni2+-Fe3+LDHs层间出现了2种空间导向和排列:即十二烷基磺酸根以单层垂直方向排布和以双层垂直方向排布在层间;十二烷基磺酸根在三元组分Co2+-Ni2+-Fe3+-LDHs层间只有一种空间排列方式,即十二烷基磺酸根以单层垂直方向排布于Co2+-Ni2+-Fe3+-LDHs层间。     

PMBP和TTA协萃剂负载泡沫塑料萃取Sc~(3+)、Y~(3+)、Nd~(3+)、Er~(3+)的性能研究

论述了将ＰＭＢＰ和ＴＴＡ协萃剂负载于聚醚型聚氨酯泡沫塑料上,萃取微量稀土元素钪、钇、钕、铒的最佳实验条件（萃取剂浓度、温度、酸度）。研究了它们的萃取性能（萃取百分率、分配比、萃取容量）。说明这是可行的萃取方法。     

Er3+ cross-section spectra of Er3+/Pr3+:Gd3Ga5O12 single-crystal: Pr3+-codoping effect

Fluorescence and absorption spectra at 530 nm (²H_11/2→⁴I_15/2), 560 nm (⁴S_3/2→⁴I_15/2), 660 nm (⁴F_9/2→⁴I_15/2), 980 nm (⁴I_11/2→⁴I_15/2), 1530 nm (⁴I_13/2→⁴I_15/2), and 2710 nm (⁴I_11/2→⁴I_13/2) of Er³⁺ in Gd₃Ga₅O₁₂ single-crystal codoped with Pr³⁺ have been measured. Judd-Ofelt analysis yields the intensity parameters Ω₂ = (0.68 ± 0.03) × 10⁻²⁰ cm², Ω₄ = (0.60 ± 0.07) × 10⁻²⁰ cm², and Ω₆ = (0.90 ± 0.17) × 10⁻²⁰ cm². A comparison with previously reported values of Er³⁺-only doping case shows that Pr³⁺-codoping causes slight change of both Ω₂ and Ω₄, while onefold increase of Ω₆. From calculated radiative rates and measured fluorescence spectra, Er³⁺ emission cross-section spectra were calibrated at first. Then, the absorption cross-section spectra were calculated using McCumber relation. In parallel, the absorption cross-section spectra were also obtained from the measured absorption spectrum, and compared with those obtained from the McCumber relation. The comparison shows that both methods give consistent result of absorption cross-section spectrum. Further comparison with Er³⁺-only doping case shows that Pr³⁺-codoping causes considerable change of Er³⁺ cross-section value. In spectrally mixing regions of Er³⁺ and Pr³⁺, Pr³⁺ emission affects little the determination of Er³⁺ emission cross-section as Pr³⁺ fluorescence is much weaker than Er³⁺ fluorescence due to low Pr³⁺ concentration.     

Fe3+和Al3+对阻垢效果的影响

本研究采用静态法评价了在Fe^3 和Al^3 存在下，各种比较典型的单体阻垢剂(包括有机膦酸盐和聚羧酸盐)对碳酸钙和硫酸钡的阻垢能力。实验研究表明：对于阻碳酸钙垢来说，各种阻垢剂受Fe^3 和Al^3 的影响不大；对于阻硫酸钡垢来说，所有药剂在Al^3 存在下其阻垢性能均大幅度下降；而Fe^3 对阻硫酸钡的影响则可以分为三种情况：(1)在所考察的药剂中，大部分药剂的阻钡垢的效果均大幅度降低；(2)氨基三甲叉膦酸(ATMP)受其Fe^3 和Al^3 的影响不大；(3)羟基叉二膦酸(HEDP)的阻钡垢的能力有所增加。     

Photoluminescence analysis of Sm3+ and DY3+ doped PVA films

A couple of Poly vinyl alcohol (PVA) films with Sm³⁺ and Dy³⁺ ions have been prepared by a conventional solution cast technique. For these Sm³⁺ and Dy³⁺ doped PVA films, Fourier transform infrared and also absorption spectral measurements have been carried out. Excitation and emission spectra and decay curves have been recorded to understand emission performance of the polymers namely Sm³⁺: PVA film with λ_exci = 400 nm and Dy³⁺: PVA film with λ_exci = 349 nm. Emission performances of these films have been explained in terms of relevant energy level schemes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Abnormal upconversion luminescence induced by defects and Er3+–Yb3+ distance change in Cs3GdGe3O9:Er3+/Yb3+ phosphors

A series of Er³⁺/Yb³⁺ co-doped Cs₃GdGe₃O₉ (CGG) phosphors were prepared by solid-phase sintering method, and the microstructure and upconversion luminescence (UCL) properties were tested by variable-temperature X-ray diffractometry and variable-temperature spectrometer. Abnormal UCL phenomena were found, which include UCL intensity continuously increasing under 980 nm laser continuous irradiation and UCL thermal enhancement. After 10 min of continuous irradiation by 980 nm laser at 513 K, the UCL intensity increased 2.91 times compared with the initial UCL intensity. The phenomenon is due to the electron releasing of host defects. The green UCL intensity of CGG:0.1Er³⁺/0.2Yb³⁺ decreases at 303–423 K and increases at 423–723 K, which reaches 13.23 times compared with that at 423 K. The phenomenon is due to Er³⁺–Yb³⁺ distance change by temperature and phonon-assisted transitions. In addition, the absolute temperature sensitivities of samples are calculated by luminescence intensity ratio technology, the maximum absolute sensitivity of CGG:0.1Er³⁺/0.4Yb³⁺ is 0.00691 K⁻¹ at 546 K, and the maximum relative sensitivity of CGG:0.1Er³⁺/0.1Yb³⁺ is 0.01224 K⁻¹ at 303 K. These results indicate that CGG:Er³⁺/Yb³⁺ phosphors can be used as a high-temperature optical thermometer.     

Luminescence properties of Eu3+- and Tb3+-doped δ-Bi2O3 stabilized by Th4+ substitution

The extent of incorporating Eu³⁺ and Tb³⁺ for bismuth in the oxygen-deficient fluorite structured Bi_0.50Th_0.50O_y has been examined together with the comprehension of their luminescence characteristics. The samples were synthesized by solution combustion method from which doping limits of Eu³⁺ and Tb³⁺, respectively, in the fluorite structure was determined. Uniform distribution of constituent elements was confirmed from elemental mapping. Doping Eu³⁺ and Tb³⁺-ions introduced compressive strain and oxygen vacancies in the system. Raman spectra of doped samples confirmed the fluorite structure and revealed the existence of oxygen vacancies in them. While Tb-doped samples showed a systematic decrease in band gap with increase in dopant concentration, such systematic variation was not observed for Eu-doped samples. Conclusions about the local site symmetry around Eu³⁺ and Tb³⁺ ions in the defect fluorite structure have been drawn from the photoluminescent spectral analysis of doped samples. Energy transfer from Bi³⁺ to Eu³⁺ and Tb³⁺-has been observed in these samples. The Judd-Ofelt analysis has been carried out to understand luminescence characteristics in these samples.     

Tb3＋自敏化效应与Gd3＋-Tb3＋能量转移对硅酸盐玻璃发光性能的影响

研究了Tb3+自敏化效应与Gd3+-Tb3+能量转移对硅酸盐玻璃发光性能的影响.结果表明,随着Tb3+掺杂量的增加,Tb3+的400～450 nm蓝色荧光发射减弱,而485 nm和545 nm绿光发射增强.Tb3+掺杂硅酸盐玻璃中,Tb3+之间存在能量转移,产生自敏化效应,这种转移是由Tb3+之间电偶极-电四极的相互作用引起的共振能量转移.Gd3+通过Gd3+-Tb3+间的能量转移对Tb3+的发光起敏化作用,这种能量转移主要是偶极与偶极相互作用引起的共振转移.     

Thermoelectric properties of La3+ and Ce3+ co-doped CaMnO3 prepared by tape casting

The structural and thermoelectric transport properties of Ca_0.9La_0.1–xCe_xMnO_3–δ (x = 0 – 0.1) prepared through tape casting process were investigated. The thermoelectric transport properties of CaMnO₃ were optimized by the La³⁺ and Ce³⁺ co-doping and tape casting process. The Ce³⁺ substitution substantially enhanced the dimensionless figure-of-merit (ZT) due to the increases in electrical conductivity and absolute Seebeck coefficient. Of the studied samples, Ca_0.9La_0.025Ce_0.075MnO_3–δ had the maximum ZT (0.17) at 800 °C, and this value was 42% and 70% larger than those of singly doped Ca_0.9La_0.1MnO_3–δ (0.12) and Ca_0.9Ce_0.1MnO_3–δ (0.10), respectively. We demonstrate that both the La³⁺ and Ce³⁺ co-doping and tape casting process are highly promising approaches in enhancing the high-temperature thermoelectric transport properties of CaMnO₃.     

Enhanced luminescence properties and energy transfer in Ce3+ and Tb3+ co-doped NaCaBO3 phosphor

A series of color-tunable NaCaBO₃: Ce³⁺, Tb³⁺ phosphors have been synthesized on the basis of efficient Ce³⁺→Tb³⁺ energy transfer. The photoluminescence emission and excitation spectra, the lifetime, and the effect of Tb³⁺ concentration are investigated in detail. The enhanced photoluminescence of Tb³⁺ with sharp emission lines could be obtained by the broad excitation band from the allowed 4f–5d absorption of Ce³⁺ ions. The intensity ratio of blue emission from Ce³⁺ and green emission from Tb³⁺ can be tuned by adjusting their concentrations. The energy transfer from Ce³⁺ to Tb³⁺ in NaCaBO₃ was found to be an electric dipole–quadrupole interaction.     

Enhanced upconversion emission in Yb3+ and Er3+ codoped NaGdF4 nanocrystals by introducing Li+ ions

β-NaGdF(4)?:?Yb(3+)/Er(3+) nanoparticles (NPs) codoped with Li(+) ions were prepared for the first time via a thermal decomposition reaction of trifluoroacetates in oleylamine. The influence of site occupancy of Li(+) on the upconversion emission of β-NaGdF(4)?:?Yb(3+)/Er(3+) NPs was investigated in detail. The upconversion emission intensity was significantly enhanced by introducing different concentrations of Li(+) ions. In contrast to lithium-free β-NaGdF(4)?:?Yb(3+)/Er(3+), the green and red UC emission intensities of the NPs codoped with 7 mol% Li(+) ions were enhanced by about 47 and 23 times, respectively. The luminescence enhancement should be attributed to the distortion of the local asymmetry around Er(3+) ions. The mechanisms for the enhancement of upconversion emission were discussed. In addition, it was found in our research work that β-NaGdF(4)?:?Yb(3+)/Er(3+) NPs exhibited paramagnetic features at room temperature and the magnetization was slightly increased by introducing Li(+) ions.     

Preparation of environmentally friendly high-emissivity Ca2+-Fe3+ co-doped LaAlO3 ceramic

Ca²⁺-Cr³⁺ co-doped LaAlO₃ is an excellent ceramic material with high emissivity; however, it is harmful to the environment because of the presence of Cr³⁺ ions. In this study, Ca²⁺-Fe³⁺ co-doped LaAlO₃ ceramic materials were successfully prepared via a high-temperature solid-state reaction. The emissivity of Ca²⁺-Fe³⁺ co-doped LaAlO₃ was 0.91, which is approximately equal to that of Ca²⁺-Cr³⁺ co-doped LaAlO₃. To compensate for the lack of data on the thermophysical properties of doped LaAlO₃ high-emissivity ceramics, the thermal expansion coefficients and thermal conductivities of LaAlO₃ doped with Ca²⁺-Fe³⁺ or Ca²⁺-Cr³⁺ were investigated. The thermal conductivities of La_0.9Ca_0.1Al_0.9Fe_0.1O₃ and La_0.9Ca_0.1Al_0.9Cr_0.1O₃ at 1200°C were 3.802 and 3.707 W·m⁻¹·K⁻¹, respectively. The thermal expansion coefficients of La_0.9Ca_0.1Al_0.9Fe_0.1O₃ and La_0.9Ca_0.1Al_0.9Cr_0.1O₃ at 1200°C were 11.49×10⁻⁶ and 11.41×10⁻⁶ K⁻¹, respectively. These results indicate that Ca²⁺-Fe³⁺ co-doped LaAlO₃ exhibits great potential as a new generation of environmentally friendly near-infrared radiating materials in the field of energy efficiency.     

Er~(3+)-Tm~(3+)共掺碲酸盐玻璃中近红外超宽带发光性质

研究了Er~(3+)-Tm~(3+)共掺TeO_2O-Nb_2O_5-Ln_2O_3(TKNL)碲酸盐玻璃的近红外发光光谱以及上转换光谱性质,该碲酸盐玻璃的起始析晶温度与玻璃转变温度之差△T为136℃,表明此玻璃具有良好的热稳定性,有利于拉制光纤。在808 nm半导体激光器的激发下在近红外波段观察到半高宽为185 nm的宽带近红外发光。通过对不同Tm~(3+)浓度以及不同激发波长下TKNL玻璃的近红外发光以及上转换发光的研究,探讨了Er~(3+)m~(3+)之间的能量传递机理。上述玻璃材料有望用作S和C波段光纤放大器的增益介质。     

Trap level analysis of Ce3+ and Sm3+ in Li6Y(BO3)3

The polycrystalline compounds of Li₆Y(BO₃)₃: Ce³⁺ and Sm³⁺ co-doped polycrystalline samples were prepared by using standard solid state reaction method. The energy levels of the doped lanthanide ions (Ce³⁺ and Sm³⁺) in the borate host materials were investigated by Thermoluminescence (TL) glow peak analysis. The co-doped samples, exhibits the TL peak at higher temperature region around 511?K whereas the Ce³⁺ individually doped sample has peak around 433?K. The X-ray excited emission spectra were carried out for all the prepared samples and found the characteristic emission bands. The trap depths (E) were calculated by using several standard methods, namely peak shape method or chen's (PS), variable heating rate (VHR), initial rise (IR) and computerized glow curve deconvolution (CGCD). The mean activation energy of the co-doped samples found to be 1.21 (0.07±) eV and the frequency factor around 1.38?×?10¹¹ Sec^?1. The calculated trap depths and the predicted energy level values were compared and found in good agreement. This primarily results suggest that the energy level scheme can help in the development of new TL materials suitable in dosimetry.     

3D打印多通道微反应器用于萃取分离In3+和Fe3+

将微流体萃取技术与新兴的3D打印技术相结合，设计并制造了一种结构较为复杂的多通道微流体萃取反应器，通过在微反应器内增加混合反应通道的数目来放大其处理量，以期使3D打印多通道微反应器在能够继承微流体单级萃取效率高优点的同时，也能够极大地扩大其处理量。反应器的结构特征主要包括两相入口、液滴筛板、混合萃取通道、混合液汇集腔及混合液出口等。将此种反应器用于不同初始条件下从硫酸溶液中萃取和分离In³⁺和Fe³⁺的实验，结果表明：随着两相接触时间的增长，萃取剂P204对于金属离子的萃取率呈现出先减小，再增大的趋势；溶液中In³⁺和Fe³⁺的分离系数在pH为0.7、接触时间为90s、萃取剂体积分数为30%时，达到最高值381.9。对初始溶液pH、萃取剂在油相中的体积分数、两相的接触时间等单因素对In³⁺和Fe³⁺的萃取率和分离系数的影响作了详细调查。     

Effect of Gd3+/Ga3+ on Yb3+ emission in mixed YAG at cryogenic temperature

We investigated the effect of Gd³⁺ and Ga³⁺ on Yb:YAG emission at cryogenic temperatures by preparing ceramic pellets by solid state reaction method with different Gd³⁺ and Ga³⁺ content. Incorporation of Gd³⁺ shows only a small effect on spectral broadening whereas incorporation of Ga³⁺ in Yb:YAG results in significant broadening. Such an inhomogeneous broadening is due to the replacement of larger Ga³⁺ ion in two different cationic sites of Al³⁺ which causes a change in local crystal field on the Yb³⁺ site.     

Nd3＋、Er3＋、Gd3＋和La3＋对超氧化物歧化酶活性的影响

通过研究Nd3＋、Er3＋、Gd3＋和La3＋稀土离子对枯草芽孢杆菌在生长过程中所产的超氧化物歧化酶活性的影响,来探讨稀土可能会导致生物体发生氧化损伤。利用改良的邻苯三酚自氧化法测定超氧化物歧化酶活性。结果表明：4种稀土离子对其细胞中超氧化物歧化酶活性均有抑制作用,且Nd3＋的抑制作用较其它3种稀土离子要强,故一定浓度的稀土离子很有可能会导致生物体发生氧化损伤。4种稀土离子的浓度不同影响有所不同,总的来说,稀土离子的浓度越大,对枯草杆菌抗氧化的抑制作用越明显,损伤毒性作用越强。     

镧和铁掺杂纳米TiO_2的制备及其光催化性能

采用溶胶-凝胶法,制备了TiO2、Fe3+/TiO2、La3+/TiO2、Fe3+-La3+/TiO2光催化剂。考察了焙烧温度、焙烧时间和掺杂离子的种类和用量对催化剂用于紫外光催化降解亚甲基蓝性能的影响。制备纯TiO2、Fe3+/TiO2和La3+/TiO2的适宜焙烧温度分别为673,673和773 K,适宜焙烧时间为120min(TiO2)、180min(La3+/TiO2)。La3+/TiO2中La3+的适宜掺杂量为1.0%,Fe3+/TiO2中Fe3+的适宜掺杂量为0.04%,Fe3+-La3+/TiO2中,当La3+的掺杂量为1.0%时,Fe3+的适宜掺杂量为0.02%,相应的脱色率为99.83%,99.51%,98.73%。当掺杂量适当时,4种催化剂用于紫外光催化降解亚甲基蓝的活性次序为:La3+/TiO2>Fe3+/TiO2>Fe3+-La3+/TiO2>TiO2。根据XRD结果,由谢乐公式估算出所得光催化剂为纳米粒子。     

Color-tunable properties of Eu3+- and Dy3+-codoped Y2O3 phosphor particles

Rare-earth phosphors are commonly used in display panels, security printing, and fluorescent lamps, and have potential applications in lasers and bioimaging. In the present study, Eu³⁺- and Dy³⁺-codoped uniform-shaped Y₂O₃ submicron particles were prepared using the urea homogeneous precipitation method. The structure and morphology of the resulting particles were characterized by X-ray diffraction, field emission scanning electron microscope, and field emission transmission electron microscope, whereas their optical properties were monitored by photoluminescence spectroscopy. The room-temperature luminescence color emission of the synthesized particles can be tuned from red to yellow by switching the excitation wavelength from 254 to 350 nm. The luminescence intensities of red and yellow emissions could be altered by varying the dopant concentration. Strong quenching was observed at high Eu³⁺ and Dy³⁺ concentrations in the Y₂O₃ host lattice.     

Er3+-Yb3+ ions doped fluoro-aluminosilicate glass-ceramics as a temperature-sensing material

The transparent Er³⁺-Yb³⁺-doped fluoro-aluminosilicate glass-ceramic (GC) was prepared by melt-quenching. The crystal phase, morphology, and up-conversion (UC) luminescence of as-produced GC were characterized by X-ray diffraction, scanning electron microscopy, and fluorescence spectrophotometry, respectively. The results show that BaYF₅ nanocrystals were uniformly distributed in the glass matrix of the as-produced GC. When the as-produced GC was subjected to heat treatment, the crystallinity was increased, but the crystal identity remains unchanged. Such heat-treatment doubled the intensity of the UC luminescence, and this enhancement was ascribed to the increased incorporation of both Er³⁺ and Yb³⁺ ions into the lower phonon energy environment of BaYF₅ nanocrystals. Furthermore, the heat-treated GC was stable against further crystallization, and consequently its UC luminescence was stable at the application temperature. The heat-treated GC was found to possess an outstanding temperature-sensing capability.