Electronic absorption spectrum of Co2 ions doped in potassium dihydrogen phosphate single crystal

Single crystals of Potassium dihydrogen phosphate doped with Co²⁺ ions were grown by slow evaporation at room temperature from a saturated solution of Potassium dihydrogen phosphate to which 0.5 mole percent of Cobalt phosphate was added as an impurity, Electronic absorption spectra have been recorded at room and liquid nitrogen temperatures on Cary - 2390 Spectrophotometer. When the crystal is cooled to liquid nitrogen temperature, changes in intensity and band position are observed and some of the bands are splitted. From the nature and position of the bands, a successful interpretation of all the observed bands have been made and identified as those belonging to Co²⁺ ion in an octahedral crystal field. The crystal field parameters derived for room temperature are Dq = 860 cm^-1, B = 920 cm^-l and C = 3680 cm^-1 and for liquid nitrogen temperature are Dq = 870 ^cm-l, B = 920 cm^-1, C = 3680 cm^-l and S = 500 cm^-1.     

Optical absorption spectrum of Cr3 ions in sodium ammonium sulphate dihydrate single crystal

Optical absorption spectrum of Cr³⁺ ions doped in sodium ammonium sulphate dihydrate single crystal has been studied both at room and liquid nitrogen temperatures. The observed bands were explained satisfactorily assuming octahedral symmetry for the Cr³⁺ ion in the crystal. The crystal field parameters Dq = 1750 cm^-1, B = 735 cm^-1 and C = 3220 cm^-1 are found to give a good fit to the observed band positions.     

Electronic absorption spectrum of Cu2 ions doped in lithium ammonium sulphate crystal

Single crystals of Lithium Ammonium Sulphate doped with Cu²⁺ ions were grown by slow evaporation technique. Electronic absorption spectra have been recorded at room and liquid nitrogen temperatures on Cary-2390 spectrophotometer. The spectrum is characteristic of a Cu²⁺ ion in octahedral symmetry. From the magnitude and and relative position of the bands a successful interpretation of all the observed bands has been made. The crystal field and tetragonal field parameters are derived. The observed and calculated energies are in good agreement.     

Optical absorption spectrum of Ni2 ions in sodium ammonium sulphate dihydrate single crystal

The Optical absorption spectrum of Ni²⁺ in sodium ammonium sulphate dihydrate single crystal has been studied at room and liquid nitrogen temperatures. The spectrum shows characteristic features of Ni²⁺ ions in octahedral crystalline fields. The splitting in one of the bands at liquid nitrogen temperature has been explained as due to spin-orbit interaction. The observed band positions have been fitted with the parameters B, C, Dq and E     

The 90° brillouin scattering in β-BiNbO4 single crystal

The acoustic modes propagated in the bc plane of triclinic β-BiNbO₄ single crystal are investigated by the Brillouin scattering method at room temperature. The Brillouin spectra corresponding to the longitudinal acoustic mode are analyzed to evaluate the elastic constants. Obtained elastic constants are c33 = 16 ± 2, c22=27 ± 3 and c23+2c44=25 ± 3 in the unit of 10¹¹ dyne· mid;cm^-2.     

反气相色谱法与汉森溶解度参数软件测定原煤的三维溶解度参数

采用反气相色谱法（IGC）研究原煤在温度433.15、443.15、453.15、463.15和473.15 K时的三维溶解度参数（HSP）,并使用外推法得到原煤室温（298.15 K）时HSP的色散力分量（δ_d）、极性力分量（δ_p）、氢键力分量（δ_h）以及校正溶解度参数（δ_t）分别为δ_d=20.83（J·cm^-3）^1/2,δ_p=11.95（J·cm^-3）^1/2,δ_h=11.08（J·cm^-3）^1/2,δ_t=26.44（J·cm^-3）^1/2。同时,采用汉森三维溶解度参数软件（HSPiP）模拟原煤在室温下的HSP,得到δ_d=19.92（J·cm^-3）^1/2,δ_p=11.18（J·cm^-3）^1/2,δ_h=11.47（J·cm^-3）^1/2,δ_t=25.56（J·cm^-3）^1/2。IGC与HSPiP得出的数据一致,研究结果为煤的热力学性质研究及其溶胀剂的选择等应用提供了参考。     

Optical Reflectance Spectra of Cr3+ in MgO Solid Solutions

The effect of Cr³⁺ concentration in an MgO crystal lattice on the crystal field splitting energy, 10 Dq , and on other electronic transitions was studied. Optical reflectance spectra showed a linear increase in 10 Dq with increasing Cr³⁺ concentration up to the limit of solid solubility. The Racah parameter, B, decreased and the energy of the ⁴T_1g→⁴A_2g transition increased with increasing Cr³⁺ concentration. The increase in 10 Dq was related to the decrease in lattice parameter.     

麦羟基硅钠石的可控合成及其阳离子交换性能研究

目前,开发绿色高效的重金属吸附材料受到人们的广泛关注。以硅藻土为原料,经水热法选择性地制备了2类硅酸盐材料即麦羟基硅钠石和方沸石。吸附测试结果表明,麦羟基硅钠石层间的钠离子能够与锂离子、镁离子、锌离子、钴离子、镍离子、铜离子等进行阳离子交换且能保持层状母体框架的稳定性。以钴离子、镍离子为例深入研究其吸附动力学和吸附机制发现,钴离子和镍离子的嵌入分别将麦羟基硅钠石的层间距由本征的1.56 nm减小到0.24、0.23 nm;室温下,对钴离子、镍离子的最大吸附量分别可达45、39 mg/g,均符合Langmuir单层吸附模型;钠离子的置换量大约是吸附的钴离子、镍离子量的两倍,证实层间离子交换主导吸附化学过程。因此,麦羟基硅钠石材料在多金属硅酸盐功能材料的合成以及环境吸附净化领域具有较大的应用潜力。     

The interaction of NO with Co/Co redox centres in CoAPOs catalysts: FTIR and UV–VIS investigations

The interaction of NO with Co²⁺/Co³⁺ redox sites in CoAPO-18 and CoAPO-5 catalysts was studied by means of FTIR and diffuse reflectance UV–Vis spectroscopy both at 298 and 85 K. Two families of Co²⁺ sites were found in the CoAPO-18 structure. (A) Ions in framework [Co²⁺(OH)P], associated with Brønsted acid sites which adsorb NO to produce dinitrosyls absorbing at 1903 and 1834 cm⁻¹; these dinitrosyl complexes are reactive, in that Co²⁺ is oxidized to Co³⁺ and N₂O is formed. (B) Structural defects Co²⁺ (Lewis acid sites) which stabilize dinitrosyls absorbing at 1900 and 1813 cm⁻¹. The NO adsorption both on reduced and, more significantly, on oxidised CoAPO-18 also leads to the formation of NO₂^δ+ adsorbed species. It was found that the two kinds of dinitrosyl complexes have different reactivity in presence of oxygen. Both families of sites are also present in CoAPO-5 catalysts on which, however, the redox reaction upon NO adsorption does not occur significantly.     

SrFe0.6Co0.4O3催化降解孔雀石绿的研究

具有复杂分子结构的三苯甲烷类染料孔雀石绿是一种典型的较难降解染料,是工业废水处理的难点之一。本文根据Goldschmidt半径容差规则法,设计了用于孔雀石绿降解的ABO₃型SrFe_(1-x)Co_xO₃催化剂,并选择出活性较高的SrFe_0.6Co_0.4O₃催化剂。通过XRD、SEM、BET吸附及XPS分析表明:该催化剂是纯净钙钛矿结构,颗粒形貌为无规则堆叠的“蜂窝”片状;吸附等温线没有明显的回滞环,说明没有“墨水瓶”类孔结构;XPS谱中,B位离子同时存在Fe²⁺/Fe³⁺和Co²⁺/Co³⁺ 4种价态离子,且反应前后,4种离子的分布比例有较大变化。根据实验结果,推测该催化反应机理为:催化剂B位Co³⁺与溶解氧形成活性氧[O₂]⁺和Co²⁺;活性氧[O₂]⁺完成氧化反应后其正电荷转移到B位Fe²⁺上形成Fe³⁺,Fe³⁺的正电荷可再转移到Co²⁺形成Co³⁺,完成催化过程的电荷转移与循环。     

固相法制备掺杂型高色度CoxM1-xAl2O4/高岭土复合颜料

为了制备低成本、高色度的钴蓝颜料,本文以高岭土为载体,以Al₂O₃和Co₃O₄为主要原料,通过引入ZnO、CaO及MgO不同金属氧化物,采用固相法制备了高色度(Co_xM_1-xAl₂O₄)/高岭土复合颜料(M为Ca²⁺、Mg²⁺或Zn²⁺)。系统考察了研磨时间、煅烧温度、煅烧时间和不同金属氧化物掺量对复合颜料呈色性能的影响规律。研究表明,在煅烧温度1 200 ℃、研磨时间12 h和n(Co²⁺)/n(M²⁺)为3:2时,制得的复合颜料具有最好的呈色性能(L^*=53.68,a^*=7.58,b^*=-62.89)。同时,引入不同的金属元素,可实现对复合颜料颜色的调控,引入Ca²⁺后,所制备的Co_xCa_1-xAl₂O₄复合颜料偏红相,而引入Zn²⁺后,所制备的Co_xZn_1-xAl₂O₄复合颜料偏绿相。通过相关表征,提出了复合颜料的呈色机理,在颜料制备过程中,引入与Co²⁺离子半径接近的Mg²⁺或Zn²⁺,Mg²⁺或Zn²⁺可进入CoAl₂O₄的四面体配位中,部分替代Co²⁺,形成MgAl₂O₄-CoAl₂O₄或ZnAl₂O₄-CoAl₂O₄的固溶体,而引入离子半径较大的Ca²⁺,形成CaAl₂O₄和CoAl₂O₄的均相混合物。最后,将制得复合颜料应用到有机硅耐热涂料中,可以明显提高有机硅涂料的热稳定性。     

油页岩灰渣合成P型沸石及对Co2+吸附性研究

以油页岩灰渣为研究对象,采用碱熔-水热合成法合成P型沸石,研究了灰碱比、碱熔温度、水热温度、NaCl添加量等条件对合成P型沸石的影响,并利用制备的P型沸石进行了对Co²⁺的吸附性能试验,结果表明,NaCl的添加有利于沸石合成,而灰碱比、碱熔温度、水热温度的提高不利于沸石合成。油页岩灰渣与P型沸石对废水中Co²⁺的去除率都随着吸附剂投加量的增加而呈上升趋势。P型沸石对Co²⁺的吸附性能优于油页岩灰渣。并且随着Co²⁺溶液初始浓度的增加,P型沸石对Co²⁺的去除率逐步递减。     

聚酰胺接枝纤维素的合成及对金属离子的吸附性能

以葡萄秸秆为原料提取纤维素,以环氧树脂为交联剂,将聚酰胺交联到纤维素上制得聚酰胺-葡萄纤维素吸附剂。测定聚酰胺-葡萄纤维素吸附剂对Co2+和Fe2+的吸附性能,并研究环氧树脂用量、反应温度和吸附平衡时间对吸附性能的影响。结果表明,当反应温度25℃、吸附平衡时间60 min和m(聚酰胺)∶m(葡萄纤维素)∶m(环氧树脂)=2∶1∶1.5时,制备的聚酰胺-葡萄纤维素吸附剂的吸附性能最好。聚酰胺-葡萄纤维素吸附剂对Co2+和Fe2+的吸附均在60 min后达到平衡,Fe2+和Co2+的最大吸附容量分别为22.40 mg·g-1和16.82 mg·g-1。     

CO2+离子交换NaX分子筛催化苯乙烯环氧化

将5次固态交换制备的Co²⁺-NaX于500 ℃焙烧6 h,再进行一次固态交换制备高稳定性催化剂,ICP分析表明其Co²⁺含量为9.13%,高于5次固态交换Co²⁺-NaX的平衡Co²⁺含量（8.42%）。采用XRD、N₂吸附-脱附对催化剂进行表征,结果表明,分子筛离子交换后其骨架结构没有受到破坏,然而随交换进入分子筛Co²⁺含量增多,其有序性下降越明显。通过正交实验对该催化剂催化苯乙烯环氧化进行考察,确定了优化的反应条件：苯乙烯用量6 mL,催化剂1.0 g,溶剂48 mL,反应温度80 ℃,反应时间6 h。在此条件下,环氧苯乙烷平均收率为39.5%。采用该法制备催化剂其活性能够进一步提高,且重复使用活性保持不变。     

显微拉曼成像技术在钽酸锂晶体的成分、缺陷和应力分布表征中的应用研究

采用激光共聚焦显微拉曼光谱仪分别对钽酸锂晶体进行了显微拉曼成像测试研究,以865 cm^-1特征峰峰强度对钽酸锂的成分分布进行了显微拉曼成像;以865 cm^-1特征峰半高宽对晶体中锂含量分布进行了显微拉曼成像;以750 cm^-1缺陷峰强度对晶体中的本征缺陷分布进行了显微拉曼成像;以865 cm^-1特征峰峰位置对晶体中的应力分布进行了显微拉曼成像。测试结果表明,显微拉曼成像可以很好地对钽酸锂单晶片的化学成分和组分、本征缺陷、应力等化学物理性质的微观分布进行成像,未掺杂三氧化二铁比掺杂了三氧化二铁的钽酸锂晶体的成分和锂含量分布更加均匀,未掺杂三氧化二铁和掺杂了三氧化二铁的钽酸锂晶体的本征缺陷分布皆比较均匀且很少,未掺杂三氧化二铁比掺杂了三氧化二铁的钽酸锂晶体的应力分布更加均匀,掺杂了三氧化二铁的钽酸锂晶体存在明显的应力分布集中的区域。     

煤沥青与石油沥青共混改性及其热解特性

考察了不同添加量的煤沥青四氢呋喃萃取物(THFS)对石油沥青的改性,随着THFS添加量的增多,改性沥青针入度降低,软化点升高,延度下降,参照英国标准(BSI BS—3690)得出最佳添加量为8%。利用TG-FTIR、FTIR对改性沥青进行了表征,结果表明:THFS、改性沥青的失重率大于基质沥青70的失重率; THFS在700～900cm^-1处芳香烃类的透射峰强度明显强于基质沥青与改性沥青;沥青老化后在2953cm^-1和1377cm^-1(—CH₃)、1461cm^-1和2924cm^-1(—CH₂—)处透射峰逐渐增强;1600cm^-1(C=O和苯环C=C)透射峰逐渐增强;沥青热解半焦中的脂肪烃类物质含量较少,主要以高度缩合的稠环芳香烃类物质为主;沥青在老化过程中主要发生了氧化、裂解、加成、聚合、缩合等反应。     

绝缘衬底上化学气相沉积法生长石墨烯材料

利用化学气相沉积法,在Si衬底、蓝宝石衬底和SiC衬底上生长石墨烯材料,研究石墨烯的表面形貌、缺陷、晶体质量和电学特性。原子力显微镜、光学显微镜和拉曼光谱测试表明,Si₃N₄覆盖层可以有效抑制3C-SiC缓冲层的形成;低温生长有利于保持材料表面的平整度,高温生长有利于提高材料的晶体质量。5.08 cm蓝宝石衬底上石墨烯材料,室温下非接触Hall测试迁移超过1000 cm²·V^-1·s^-1,方块电阻不均匀性为2.6%。相对于Si衬底和蓝宝石衬底,SiC衬底上生长石墨烯材料的表面形态学更好,缺陷更低,晶体质量和电学特性更好,迁移率最高为4900 cm²·V^-1·s^-1。     

超声波强化制备高取代度大米淀粉乙酸酯

高取代度乙酸酯(DS>2)由于其热塑性及疏水性, 在高分子领域应用广泛。以大米淀粉为原料, 对甲苯磺酸为催化剂, 在冰乙酸/乙酸酐体系中, 采用了超声强化方法制备高取代度乙酸酯淀粉, 并用FTIR、XRD 和SEM对产物进行表征。考察了超声作用时间、超声温度、超声功率对大米淀粉乙酸酯取代度(DS)的影响, 并用响应面法对超声条件进行了优化, 得到的最佳工艺如下:超声时间为15.67min, 超声温度为31.33℃, 超声功率为85.60W, 在此条件下, 得到的乙酸酯淀粉的取代度为2.77。由FTIR图谱可知, 乙酸酯淀粉在1750cm^-1、1433cm^-1、1375cm^-1及1239cm^-1处出现了乙酰基的特征峰, 证明成功地制得了高取代度乙酸酯淀粉。XRD和SEM结果表明, 乙酰化后淀粉的结构完全被破坏。研究结果为高取代度淀粉乙酸酯的工业生产提供了依据。     

A low frequency Raman study of SrBi2Ta2O9-Bi3TiNbO9

Raman spectra of SrBi₂Ta₂O₉ (SBT), Bi₃TiNbO₉(BTN), and x(SBT) + (1-x)(BTN) samples were studied for the first time in the low frequency region. The BTN spectra show two features around 33 and 41 cm^-1, while only one feature, around 30 cm^-1, is found in SBT. The stoichiometric evolution of the Raman spectra shows that the frequency positions of these bands decrease as x changes from 0 to 1. Strong correlation is found between the frequency positions of these modes and both the Curie temperature and the a-parameter. The results are interpreted in terms of the ferroelectric displacive modes, which are responsible for the strong spontaneous polarization along a-axis. The band around 65 cm^-1is assigned to oxygen motion in the B₂O₂ layer.     

Ferroelectric Pb5-xBix (Ge.Si)3-xBxO11 single crystals as a material for IR radiation detectors

The coupled substitution of Bi³⁺ for Pb₂₊ and B³⁺ for Ge⁴⁺ was successfully achieved in ferroelectric Pb₅Ge₃O₁₁. Large single crystals of optical quality were grown from the melt. Deterioration of the crystal quality could not be observed within a period of two years under ambient conditions. The dielectric permittivity ε_r, electric conductivity p and pyroelectric coefficient γ are investigated as a function of temperature. The room temperature data (εr = 43, γ = 2.4·10^-4Cm^-2 K^-1, p = 7·10⁷ Ω, volume specific heat s = 2·10⁶ Jm^-3K^-1) show the usefulness of Pb_5-xBi_xGe_3-xB_xO₁₁ around x = 0.1 as a material for pyroelectric thermal detectors operating at room temperature. Also the difficulty of producing lead germanate silicate mixed crystals in the size and quality needed for vidicon applications is overcome by additional replacement of some Pb and Ge by Bi and B.