Ar^＋, He^＋，S^＋离子轰击n-InP单晶表面的机理研究

通过X射线光电子能谱和低能电子衍射实验研究了10～180 eV的Ar＋、 He＋、S＋离子轰击n-InP（100）表面, 发现S＋离子轰击可以产生In-S组分,减轻离子轰击对表面的物理损伤.对于Ar＋离子轰击后的表面,经过S＋离子处理和加热过程以后,表面损伤得到了修复,最终得到了2×2的InP表面,进一步验证了S＋离子对InP表面的修复作用.     

三价铁离子与硫离子反应的实验探究

探究了水溶液中Fe3+与S2-的反应，得出几点结论：生成Fe2S3的沉淀反应是动力学优势反应，生成Fe2+和S的氧化还原反应是热力学优势反应；发现Fe2S3可以与Fe3+反应生成S和Fe2+，Fe2S3在酸性条件下不稳定；在弱碱性条件下，Fe3+也有与HS-发生氧化还原反应的倾向；Fe3+在水溶液中主要以水解产物[Fe（H2O）6-n（OH）n]（3-n）+（n=1，2）存在，[Fe（H2O）6-n（OH）n]（3-n）+的氧化性很弱，难以将H2S或HS-氧化，却易与S2-结合生成Ksp极小的Fe2S3沉淀。     

Er3+，Ho3+和Tm3+在硫氧化钆中的余辉发光

The new Er^3 , Ho^3 and Tm^3 doped gadolinium oxysulfide phosphors with the long afterglow emission were synthesized by solid-state reaction method. The synthesized phosphors were characterized by X-ray diffraction. The excitation and photolumineseenee spectra, afterglow spectra and afterglow decay curve were examined by fluorescence spectroscopy. The afterglow spectra of Gd2O2S:Er^3 , Mg, Ti showed typical transitions of Er^3 at 528(2H11/2→4I15/2), 548 (^4S3/2 →^4I15/2) and 669 nm (^4F9/2→^4I15/2). In the afterglow spectra of Gd2O2S: Ho^3 , Mg, Ti,typical transitions of Ho^3 at 546 nm (^5S2→^5I8), 651 and 661 nm (^2F5→^5I8) were observed. In Gd2O2S:Tm^3 , Mg,Ti, the afterglow emission at 800 nm (^1G4→^3H5) of Tm^3 was seen. The meehnism and model of afterglow energy transfer were proposed.     

Energy disposal in thermal-energy charge-transfer reactions: Ar+,Kr+ and Xe+ with NH3

Thermal-energy charge-transfer reactions from the ²P_3/2 state of Ar⁺, Kr⁺ and Xe⁺ with NH₃ are shown to be non-energy resonant: the kinetic energy released in each case has been measured, and the internal energy of the NH⁺₃ product ions deduced. Possible quenching of ²P_1/2 state of rare-gas ions in ICR cells is discussed.     

Optical Spectroscopy of Pr3+ Ion Singly Doped LiLuF4 Single Crystal by Bridgman Method

High quality LiLuF₄ single crystals doped with various Pr³⁺ ions were synthesized by a vertical Bridgman method in completely sealed platinum crucibles. The excitation spectra spans from 420 nm to 500 nm. The prepared single crystals exhibit a blue band at 480 nm (³P₀→³H₄), a green band at 522 nm (³P₁→³H₅), and a red band at 605 nm (¹D₂→³H₄) when excited at 446 nm; their corresponding average lifetimes are 38.5 μs, 37.3 μs, and 36.8 μs, respectively, which are much longer than those in oxide single crystals. The effects of excitation wavelength and doping concentration on emission intensities and chromaticity coordinates are investigated. The optimal Pr³⁺ concentration is confirmed to be 0.5%. The temperature dependent emission shows that the emission intensity constantly decreases with the increase of temperature from 298 K to 443 K due to the enhancement of non-radiative quenching at high temperature. The ³P₀→³H₄ transition is the most vulnerable to temperature, followed by the ³P₁→³H₅ transition and ¹D₂→³H₄ transition.     

Detection of surface atoms by energy analysis of scattered primaries and recoiled secondaries from CsBr under Ar+ and Ar+ bombardment

Time-of-flight (TOF) and electrostatic sector analysis (ESA) have been used to measure particles scattered and sputtered by direct recoils and surface recoils during 3 keV Ar⁺ and 6 keV Ar²⁺ bombardment of CsBr at forward and backscattering angles. Charge fractions of scattered argon and recoiling surface atoms are obtained. Hydrogen and oxygen surface impurities are detected predominantly as directly recoiled neutrals.     

LiNbO3晶体中Yb3+的配位场能级分析

０引言自从上世纪６０年代LiNbO３晶体合成以来，人们对这种材料的兴趣越来越大。它的优良的非线性特征使LiNbO３晶体成为用于光电装置的最好的物质之一，也是信息贮存和全息照相的很好材料。稀土离子可以很容易地掺杂到该晶体中，用频率自动加倍、自猝灭开关和自动密封等方式来发展微激光。在这种意义上，Yb３＋成为主要的激光材料掺杂离子，它的光谱特征在大量体系中已有研究，已经获得了不同基质中的激光犤１～５犦。由于Yb３＋的谱带积分面积较大，所以，Yb３＋已被用作其它稀土离子的敏化剂，用以提高它们的激发效率，如：Yb－Er…     

K~+、Ca~(2+)和Fe~(3+)对和丰煤热解产物分布、结构及品质的影响

将K~+、Ca~(2+)、Fe~(3+)的硝酸盐用于处理脱灰和丰煤样(K-DC、Ca-DC和Fe-DC),在热重分析仪中考察了处理煤样的失重特征和气体逸出规律。结果表明,处理煤样的总失重率减少,CO_2和H_2的浓度较原煤(DC)的高。通过固定床研究了处理煤样热解过程中产物的分配规律,采用元素分析、FT-IR、模拟蒸馏和GC-MS等分析了半焦的结构特征和焦油的组成与品质。结果表明,与DC相比,处理煤样的半焦和气体产率增加,焦油产率降低,相应半焦的不饱和度和缩合程度降低。在各金属组分的作用下,焦油中的轻质组分分率增加,其中,Fe~(3+)的作用最为显著,其值增加了22.4%。GCMS结果表明,长链烷烃含量高达70%,是焦油组分重的主要原因,K和Fe组分可促进其分解。     

K~+、Na~+、Ca~(2+)、Mg~(2+)对胜利褐煤平衡复吸水的影响

以胜利褐煤为研究对象,利用FT-IR等手段,用灰分、不同湿度下的平衡复吸水含量等,系统研究了不同相对湿度下K+、Na+、Ca2+、Mg2+的水合作用对胜利褐煤平衡复吸水含量的影响。结果表明,相同浓度不同类型的金属离子与煤样的交换能力的趋势为Ca2+Na+K+Mg2+。金属离子对胜利褐煤平衡复吸水含量影响力的顺序为Mg2+Ca2+Na+≈K+。相对湿度高时,平衡复吸水含量的主要控制因素为游离水分子之间的分子作用力;相对湿度中等时,平衡复吸水含量的主要控制因素为金属水簇与毛细管之间的毛细管作用力;相对湿度低时,平衡复吸水含量的主要控制因素为金属离子的水合作用。     

The turn-off fluorescent sensors based on thioether-linked bisbenzamide for Fe3+ and Hg2+

Some dibenzamide derivatives with a thioether linker were designed, synthesized and characterized. The specific responses to Hg²⁺ and Fe³⁺ were investigated by fluorescence. According to fluorescence titration, the Job plot, ¹H NMR, and ESI-mass analysis, the derivative with mono-hydroxyl substituent (1b) on the aromatic ring has high selectivity for Fe³⁺ ion with the formation of 1:1 1b-Fe³⁺ complexes. The specificity of 1c for Hg²⁺ could be switched by swapping the substituent from hydroxyl to amino, and a 1:2 (1c-Hg²⁺) complex was formed. Along with the obtained results, density functional theory (DFT) and natural bond orbital (NBO) analyses, Time-dependent (TD) DFT and natural transition orbital (NTO) analyses were employed to explore the geometric structures, properties and possible mechanisms.     

CaWO4:xEu3+,ySm3+,zLi+红色荧光粉的制备及光学性能

采用微波固相法制备了CaWO₄：xEu³⁺,ySm³⁺,zLi⁺红色荧光粉。测量样品的XRD图、激发谱、发射谱及发光衰减曲线,研究并分析了Eu³⁺、Sm³⁺、Li⁺的掺杂浓度,对样品微结构、光致发光特性、能量传递及能级寿命的影响。结果表明,Eu³⁺、Sm³⁺、Li⁺掺杂并未引起合成粉体改变晶相,仍为CaWO₄单一四方晶系结构。Eu³⁺、Sm³⁺共掺样品中,Sm³⁺掺杂为3%时,Sm³⁺对Eu³⁺的能量传递最有效。Li⁺掺杂起到了助熔剂和敏化剂的作用,使样品发光更强。在394 nm激发下,与CaWO₄：3%Eu³⁺样品比较,3%Eu³⁺、3%Sm³⁺共掺CaWO₄及3%Eu³⁺、3%Sm³⁺、1%Li⁺共掺CaWO₄样品的发光分别增强2倍及2.4倍。同一激发波长下,单掺Eu³⁺样品寿命最短,Sm³⁺、Eu³⁺共掺样品随Sm³⁺浓度增加,寿命先减小后增加,且掺杂了Li⁺的样品比不掺Li⁺的样品⁵D₀能级寿命有所增加。     

Collision- and non-collision-induced predissociation in the appearance of S+ and CS+ ions from CS2 under electron impact

Metastable transitions in CS⁺₂ leading to S⁺ + CS and CS⁺ + S under electron impact on CS₂ ae reported. The predissociation processes able to explain the occurrence of these metastable transitions are discussed. An interpretation of some fast dissociation processes is suggested.     

Fe3+和Fe2+对原代培养的成骨细胞增殖、分化和矿化功能的影响

采用噻唑蓝(MTT)法、碱性磷酸酶(ALP)比活性测定、油红O染色和茜素红染色及定量分析,研究了不同浓度的Fe3+和Fe2+对原代培养的成骨细胞增殖、分化及矿化功能的影响.结果表明:浓度为1×10-9～1×10-4 mol·L-1的Fe3+和Fe2+促进成骨细胞增殖,但是在较高浓度1×10-3 mol·L-1时,它们则抑制成骨细胞增殖.与成骨细胞作用48 h,浓度为1×10-8～1×10-4 mol·L-1的Fe3+和Fe2+抑制其分化,但在较低的浓度1×10-9 mol·L-1时则对其分化没有影响:进一步延长作用时间为72 h,Fe3+对成骨细胞分化没有影响,除1×10-6mol·L-1浓度的Fe2+促进成骨细胞分化外,其他浓度的Fe2+则抑制其分化;测试浓度下的Fe3+对成骨细胞向脂肪细胞的横向分化表现为抑制或没有影响,而Fe2+的影响则依赖于浓度和作用时间.在1×10-8～1×10-5mol·L-1浓度范围内,Fe3+和Fe2+对矿化结节的影响表现出相反的效应.在较高浓度(1×10-4mol·L-1)下,它们促进矿化节结的形成,而在较低浓度(1×10-9mol·L-1)下,Fe3+抑制矿化节结的形成,Fe2+则没有影响.结果提示:浓度.作用时间和铁离子的价态都是影响Fe3+和Fe2+生物效应(从毒性到活性,从损伤到保护,从上调到下调)转变的关键因素.     

La3+对过氧化氢酶电化学和生物电催化活性的影响

本文研究了La³⁺对过氧化氢酶(CAT)的直接电化学反应活性和对H₂O₂还原的生物电催化活性的影响。发现当La³⁺浓度低时,La³⁺能提高CAT的直接电化学反应活性和对H₂O₂还原的电催化活性。当La³⁺浓度高时,La³⁺会降低CAT的直接电化学反应活性和对H₂O₂还原的电催化活性。这是由于La³⁺能与CAT的肽链上的氨基酸残基发生作用而使肽链构象发生变化,导致血红素结构发生变化。当La³⁺浓度低时,La³⁺能使血红素的非平面性增加,活性中心Fe(Ⅲ)的暴露程度增加,因此,低浓度的La³⁺能增加CAT的电化学和生物电催化活性,而高浓度的La³⁺却会使血红素的非平面性降低,活性中心Fe(Ⅲ)的暴露程度降低,因此,降低了CAT的电化学和生物电催化活性。     

脯氨酸与Cu、Cu+和Cu2+配位体系的计算研究

运用M06-2X和ωB97XD方法分别在6-311++G（2d,p）和TZVP基组水平上,对脯氨酸（Pro）的15种构象与Cu、Cu⁺和Cu²⁺形成的多种配合物的几何结构、能量学特征、振动光谱和电子结构等进行计算研究. 四种水平得到20种[Pro-Cu]、16种[Pro-Cu]⁺和16种[Pro-Cu]²⁺稳定结构. [Pro-Cu]和[Pro-Cu]⁺体系中出现12种Pro构象,而[Pro-Cu]²⁺体系中出现11种Pro构象,三种体系中最稳定的结构都不是由能量最低的Pro构象生成的. 在结构CI3、CI4、CII7和CII8中,Pro的羧基氢转移到亚氨基氮形成两性离子与Cu双配位结合. [Pro-Cu]^0/1+/2+体系四种水平计算相对能差范围逐渐增加,结合能分别在-60.0 --5.0 kJ·mol^-1、-340.0 --170.0 kJ·mol^-1和-1100.0 --860.0 kJ·mol^-1范围,配位体系中Pro的变形能逐渐增加. N―H和O―H键伸缩振动频率普遍发生红移,配位体系中部分电荷从Pro转移到Cu上,在[Pro-Cu]²⁺体系中单配位结构中电荷转移最多,约为单位负电荷.     

Thermal-energy charge transfer of Ar+ with H2O: Internal and kinetic energy of the product H2O+

The reaction of Ar⁺ with H₂O has been investigated at near-thermal energy. The product ions H₂O⁺ and ArH⁺ account for 90 and 10% of the total reaction rate, respectively. Kinetic energy measurements and emission spectroscopy of the H₂O⁺ product ions are reported. It is concluded that at least 60% of H₂O⁺ ions are in the X? state with ≈2.4 eV vibrational energy while up to 40% are in the à state with a mean vibrational energy of 1.4 eV; the à state vibrational distribution has been determined. It is shown that both H₂O⁺ states are populated via an energetically “non-resonant” charge transfer process.     

Explanation for the structural differences of S2+4, S04 and S2−4

An explanation for the geometry changes upon successive double reductions of S²⁺₄ (square planar, D_4h symmetry) to neutral S₄ (for which the structure is unknown) and finally to S^2?₄ (non-planar, C₂ symmetry) is given on the basis of orbital eigenvalues and wavefunctions calculated with the self-consistent-field Xα scattered-wave molecular orbital method.     

Er3+和Ce3+/Ce4+掺杂β-BaB2O4纳米棒的制备、结构与发光性质

以Ba(NO3)2、NaBH4、Er2O3和CeO2为原料, 在十六烷基三甲基溴化铵(CTAB)表面活性剂辅助下, 采用水热法制备了β-BaB2O4 (β-BBO)纳米棒, 稀土离子Er3+单掺杂的β-BBO(β-BBO:Er3+)及Er3+和Ce3+/Ce4+共掺杂的β-BBO(β-BBO:Er3+/Ce3+/Ce4+)纳米棒. 通过X射线粉末衍射(XRD)、傅里叶变换红外(FTIR)光谱、拉曼光谱、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和光致发光(PL)光谱分别对样品的物相、结构、形貌、成分及光致发光性质进行了表征. 研究结果表明: 微量稀土离子掺杂并不改变β-BBO的结构, 制得的纳米棒尺寸均匀, 长度在200-500 nm 之间, 直径在10-20 nm 之间; β-BBO:Er3+和β-BBO:Er3+/Ce3+/Ce4+纳米棒在400nm光激发下, 在可见光范围内都观察到中心波长为515和542 nm的绿光. 对发光机理的初步研究表明: 发光分别对应于Er3+的2H11/2→4I15/2, 4S3/2→4I15/2跃迁, 铈离子以Ce3+和Ce4+两种形式存在于体系中, Ce3+对Er3+起敏化作用, 可以显著增强β-BBO:Er3+/Ce3+/Ce4+纳米棒的发光强度, 存在Ce3+→Er3+的能量传递过程.     

有序介孔Al2O3∶RE3+的制备及Gd3+对Eu3+的能量传递

以P123为表面活性剂,异丙醇铝为铝源,用简易溶胶-凝胶法,获得了单掺和双掺Gd3+,Eu3+的介孔氧化铝组装体。用广角X-射线衍射仪(WAXD)进行了物相分析;小角X-射线衍射仪(SAXD)、比表面仪进行了孔结构分析和形貌表征;研究了组装体的发光性能并发现Gd3+对Eu3+有能量传递作用,并分析了能量传递过程。