共查询到20条相似文献,搜索用时 31 毫秒
1.
K. H. Lieser J. Bastian und A. B. H. Hecker 《Fresenius' Journal of Analytical Chemistry》1967,228(2):98-106
Zusammenfassung Die Trennung der Ionenpaare Rb+/Cs+, K+/Rb+, K+/Cs+, Na+/K+, Li+/Na+ mit Salzsäure oder Ammoniumchloridlösung als Elutionsmittel gelingt quantitativ oder nahezu quantitativ mit Hilfe von Titanhexacyanoferrat(II)-säulen. Die Cäsiumionen können nicht eluiert werden. Ebenso gelingt die Trennung der lonenpaare Sr2+/Ba2+, Ca2+/Ba2+, Ba2+/Cs+ und Sr2+/Cs+ quantitativ oder nahezu quantitativ. Auch eine partielle Trennung der Seltenen Erden ist möglich; Yttrium ist leichter eluierbar als die Lanthanide.
Summary The quantitative or nearly quantitative separation of the ion pairs Rb+/Cs+, K+/Rb+, k+/Cs+, Na+/K+ and Li+/Na+ can be achieved with hydrochloric acid or ammonium chloride solutions as eluents by means of columns of titanium hexacyanoferrate(II). The elution of the Cs+ ions is not possible. In the same way the quantitative or nearly quantitative separation of the ion pairs Sr2+/Ba2+, Ca2+/Ba2+, Ba2+/Cs+ and Sr2+/Cs+ can be achieved. Also a partial separation of the rare-earth elements is possible; yttrium is more easily eluted than the lanthanides.相似文献
2.
A recently discovered phenomenon of excessively high X-ray production is discussed. The high yield is attributed to the build-up of potential on non-conducting targets irradiated with accelerated ion beams, and the subsequent discharge. Ion-beams of1H+,1H2
+,2H+,2H2
+,3He+,3He2+,4He+,14N+,14N2+,16O+ and20Ne+ were used. A new mechanism of X-ray excitation is proposed. The increased X-ray fluxes produced by this process are suitable for analytical applications of high specificity. The mechanism of excitation associated with the process, factors affecting the high X-ray yields, applications and a general overview of the studies undertaken with the various ion beams are given. 相似文献
3.
4.
《Surface and interface analysis : SIA》2004,36(7):640-644
The chemical composition variation of silicon under 4 keV O2+ ion beam bombardment at different incident angles was studied by in situ small‐area XPS. The changes in secondary ion profile (30Si+, 44SiO+, 56Si2+, 60SiO2+) during oxygen ion beam bombardment also have been monitored. We present a direct correlation of the changes in secondary ion depth profile with surface composition during sputtering. Evolution of the secondary ion profile obtained from SIMS shows similar trends with variation of oxygen concentration in the crater surface measured by XPS. It is shown that when the oxygen ion beam incidence angle is < 40° silicon dioxide is the dominant species on the crater surface and the matrix ion species ratio (MISR) value for 44SiO+/56Si2+ is higher than for 30Si+/56Si2+. For incidence angles of >40°, the formation of sub‐oxide is favoured and thus the MISR value for 44SiO+/56Si2+ is lower than for 30Si+/56Si2. At 40° bombardment there are similar amounts of SiO2 and sub‐oxides present on the crater surface and the MISR values for 44SiO+/56Si2+ and 30Si+/56Si2+ are also similar. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
5.
F. Szelecsényi Z. Kovács K. Suzuki K. Okada T. N. van der Walt G. F. Steyn S. Mukherjee 《Journal of Radioanalytical and Nuclear Chemistry》2005,263(2):539-546
Summary Excitation functions were measured by stacked-foil technique for the natZn(p,x)61Cu, 66Zn(p,x)61Cu, 68Zn(p,x)61Cu and natZn(p,x)60Cu nuclear processes up to 100 MeV. The experimental cross sections were compared with published data. On the base of these excitation functions, the cross sections of 64Zn(p,x)61Cu process were also deduced. Integral thick target yields were calculated for the 64Zn(p,x)61Cu and nat,64Zn(p,x)60Cu processes and irradiation parameters were elaborated for the 61Cu production via the 64Zn+p reactions for low and middle energy accelerators. According to our calculations the yield of 61Cu amounts to 1.02 . 1011 Bq . A-1 . s-1 (9.9 mCi .µ A-1 . h-1) from 19®10 MeV while it reaches 3.91 . 1011 Bq . A-1 . s-1 (38 mCi . µ A-1 . h-1) in the energy range of 67®60 MeV. 相似文献
6.
CAS SCF CI (SD) calculations have been carried out for the 3Σ?g, 1Σ+g, 3Σ+u, and 5Δu states of Sc2 using large gaussian basis sets. The 3Σ?g, 1Σ+g, and 3Σ+u states arise from the 2D(4s2 3d1) + 2D(4s2 3d1) limit of Sc2 and are found to be only weakly bound (Dc ≈ 0.06 eV and Rc ≈ 8.0a0). The 5Δu state arises from the 2D(4s2 3d1) + 4F(4s1 3d1 4p1) atomic limit. This state is found to be strongly bound relative to its limits (Dc ≈ 0.8 eV and Rc ≈ 7.0a0). 相似文献
7.
Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes XXI The Influence of the PR3 Ligands on Formation and Properties of the Phosphinophosphinidene Complexes [{η2‐tBu2P–P}Pt(PR3)2] and [{η2‐tBu2P1–P2}Pt(P3R3)(P4R′3)] (R3P)2PtCl2 and C2H4 yield the compounds [{η2‐C2H4}Pt(PR3)2] (PR3 = PMe3, PEt3, PPhEt2, PPh2Et, PPh2Me, PPh2iPr, PPh2tBu and P(p‐Tol)3); which react with tBu2P–P=PMetBu2 to give the phosphinophosphinidene complexes [{η2‐tBu2P–P}Pt(PMe3)2], [{η2‐tBu2P–P}Pt(PEt3)2], [{η2‐tBu2P–P}Pt(PPhEt2)2], [{η2‐tBu2P–P}Pt(PPh2Et)2], [{η2‐tBu2P–P}Pt(PPh2Me)2], [{η2‐tBu2P–P}Pt(PPh2iPr], [{η2‐tBu2P–P}Pt(PPh2tBu)2] and [{η2‐tBu2P–P}Pt(P(p‐Tol)3)2]. [{η2‐tBu2P–P}Pt(PPh3)2] reacts with PMe3 and PEt3 as well as with tBu2PMe, PiPr3 and P(c‐Hex)3 by substituting one PPh3 ligand to give [{η2‐tBu2P1–P2}Pt(P3Me3)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3Ph3)(P4Me3)], [{η2‐tBu2P1–P2}Pt(P3Et3)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3MetBu2)(P4Ph3)], [{η2‐tBu2P1–P2}Pt(P3iPr3)(P4Ph3)] and [{η2‐tBu2P1–P2}Pt(P3(c‐Hex)3)(P4Ph3)]. With tBu2PMe, [{η2‐tBu2P–P}Pt(P(p‐Tol)3)2] forms [{η2‐tBu2P1–P2}Pt(P3MetBu2)(P4(p‐Tol)3)]. The NMR data of the compounds are given and discussed with respect to the influence of the PR3 ligands. 相似文献
8.
The vibrational spectra of a number of transition-metal complexes containing terminal or bridging nitrido (N3?) and oxo (O2?) ligands are reported. Full assignments of fundamental modes are given for (OsO314N)?, (OsO315N)?, (Os14NX4)?, (Os15NX4)?, (Ru14NX4)?, (Os14NX5)2?, (Os15NX5)2? and (Ru14NX5)2? (X = Cl, Br), and also for the oxo complexes (Mo16OCl4, (Mo18OCl4)?, (Mo16OCl5)2? and (Mo18OCl5)2?. Force constants have been evaluated for the four- and five-coordinate complexes. The significance of the results is discussed in terms of the metalligand bonding involved in these species. 相似文献
9.
Ranran Du Bingbing Suo Huixian Han Yibo Lei Gaohong Zhai 《International journal of quantum chemistry》2013,113(22):2464-2470
Potential energy curves of 22 electronic states of RhN have been calculated by the complete active space second‐order perturbation theory method. The X1Σ0+ is assigned as the ground state, and the first excited state a3Π0+ is 978 cm?1 higher. The 1Δ(I) and B1Σ+ states are located at 9521 and 13,046 cm?1 above the ground state, respectively. The B1Σ+ state should be the excited state located 12,300 cm?1 above the ground state in the experimental study. Moreover, two excited states, C1Π and b3Σ+, are found 14,963 and 15,082 cm?1 above the X1Σ+ state, respectively. The transition C1Π1–X1Σ0+ may contribute to the experimentally observed bands headed at 15,071 cm?1. There are two excited states, D1Δ and E1Σ+, situate at 20,715 and 23,145 cm?1 above the X1Σ+ state. The visible bands near 20,000 cm?1 could be generated by the electronic transitions D1Δ2–a3Π1 and E1Σ+0–X1Σ+0 because of the spin–orbit coupling effect. © 2013 Wiley Periodicals, Inc. 相似文献
10.
The ΔJ = 0,l-doublet transitions of OCS isotopes (16O12C32S, 16O12C33S, 16O12C34S, 16O13C32S and 18O12C32S) in the (0110) vibrational state have been measured in a molecular-beam electric-resonance spectrometer equipped with a nozzle source. Rotation-vibration coupling constants and electric dipole moments have been determined for all isotopes, and the spin-rotation and the quadrupole coupling constants for the 33S nucleus in 16O12C33S in the υ2=0 and υ2=1 states. 相似文献
11.
Christopher M. Johnson Mark G. Shilton Arthur T. Howe 《Journal of solid state chemistry》1981,37(1):37-43
We have measured the ionic conductivities of pressed pellets of the layered compounds MUO2PO4 · nH2O, and correlated the results with TGA data. The conductivities (in ohm?1 m?1), at temperatures increasing with decreasing water content over the range 20 to 200°C, were approximately as follows: Li+4H2O, 10?4; Li+, Na+, K+, and NH4+3H2O, 10?4, 10?2, 10?4, and 10?4; H+, Li+, and Na+1.5H2O, 10?2, 10?4, and 10?4; Na+1H2O, 10?5; H+, K+, and NH4+0.5H2O, all 10?5; and H+, Li+, Na+, K+, NH+4, and , 10?5, 10?5, 10?4, 10?5, 10?5, and 10?6. A ring mechanism is proposed to account for the high conductivity found in NaUO2PO4 · 3.1H2O. The accurate TGA data showed that most of the hydrates had water vacancies of the Schottky type, and should be represented as MUO2PO4(A ? x)H2O, where x can be between 0 and 0.3. 相似文献
12.
Probabilities of gamma-ray simultaneous emission have been calculated for the determination of correction factors of full-energy
peak areas of radionuclides with a complex decay scheme at measurements of gamma-spectra using HPGe detectors. Coincidence
probabilities were determined using the Monte Carlo method for the following radionuclides: 22Na, 24Na, 46Sc, 51Cr, 52Fe, 54Mn, 56Co, 57Co, 58Co, 59Fe, 60Co, 64Cu, 65Zn, 67Cu, 68Ge-68Ga, 75Se, 85Sr, 88Y, 94Nb, 108mAg, 109Cd, 111In, 124Sb, 125Sb, 125I, 131I, 132Cs, 133Ba, 134Cs, 139Ce, 152Eu, 153Sm, 153Gd, 155Eu, 166mHo, 169Yb, 177Lu, 186Re, 207Bi, 208Tl, 212Pb, 212Bi, 241Am. 相似文献
13.
Wei Guo Shenghong Hu Jian Zhao Shesheng Jin Wenjuan Liu Hongfei Zhang 《Microchemical Journal》2011,97(2):154-159
In the direct ICP-MS determination of Cd in feed samples, significant spectral interferences caused by high concentrations of Mo can play an important role. In the present study, Mo based oxide or hydroxide polyatomic interferences were eliminated by dynamic reaction cell (DRC) with O2 as reaction gas. Some other oxide or hydroxide interferences (i.e. Zr and Ru) were simultaneously reduced by this technology. These potentially interfering polyatomic ions 95Mo16O+, 94Mo16OH+, 94Zr16OH+, 98Mo16O+, 98Ru16O+ and 97Mo16OH+ on 111Cd+ and 114Cd+ were oxidized to higher oxides MoO2+, MoO3+, MoO4+, RuO3+, RuO4+, MoO2H+, MoO3H+, ZrO2H+ and ZrO3H+. The rejection parameter q (RPq) of DRC and the flow rate of O2 were optimized and set at 0.75 and 2.0 ml min− 1, respectively. In addition, the residual isobaric interference of 114Sn on 114Cd was corrected using a mathematical correction equation. The limit of quantitation (LOQ) for 111Cd or 114Cd was 0.8 or 1.0 ng g− 1 and the analysis results of NIST 1567a wheat flour and 1568a rice flour standard reference materials were in good agreement with the certified values. As the routine cadmium monitoring method in our laboratory, the proposed method was applied to the accuracy determination of 562 pig feed samples for the Monitoring of Central Meat Reserves (CMR) of China. 相似文献
14.
Diatomic halogens are studied with UV photoelectron spectroscopy using new techniques to preserve high resolution even for reactive species. For the first time vibrational structure is observed on the 2Πu,i (i = 1/2,3/2) states (F2+, Cl2+), the 2Σg+ states (F2+, Cl2+) and the Br2+ (2Πu,) state. On the 2Πu,i states (F2+, Cl2+, Br2+) spin-orbit splitting is resolved. Indications for a small potential barrier on the F2+ (2Πu,i) state for large internuclear distances are found. A new value for the spin-orbit splitting of the Cl2+(2Πg) state is presented (= ?725 cm?1). The complementary nature of optical emission and photoelectron spectroscopy for small ions is demonstrated leading to a more complete picture of the F2+ (2Πu,i) and Cl2+ (2Πu,i) ionic states. 相似文献
15.
Michaela Grg Uwe Dieckbreder Ralph-Matthias Schoth Gerd-Volker Rschenthaler Alexander A. Kadyrov 《Heteroatom Chemistry》1998,9(2):109-113
1,1,1,4,5,5,5-Heptafluoro-4-(trifluoromethyl)-2,3-pentanedione reacted with λ3σ3-phosphorus compounds, PR1R2R3 (R1 = CF3, R2 = R3 = Me, iPr, NEt2; R1 = NCO, R2 = R3 = OMe, OEt, R2−R3 = OCH2CH2O, OCMe2CMe2O; R1 = OSiMe3, R2 = R3 = OEt; R1 = NEt2, R2 = R3 = OCH2CF3; R1 = R2 = Et2N, R3 = OCH2CF3, OCH(CF3)2, OCH2Ph, OC6F5) to give new 1,3,2λ5σ5-dioxaphospholenes. The first λ5σ5 phosphoranes with an OCN group bonded to phosphorus were obtained. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:109–113, 1998 相似文献
16.
The characteristic collision-induced dissociations of [M ? H]? ions of dipeptides and tripeptides involve proton transfer to the carboxylate centre as a prelude to fragmentation. Dipeptides show the process NH2CH(R1)CONHCH(R2)CO2? → NH2C(R1)CONHCH(R2)CO2H → ?NHCH(R2)CO2H + NH2C(R1)?C?O (R = H or alkyl) while tripeptides show the analogous processes NH2CH(R1)CONHCH(R2)CONHCH(R3)CO2? → NH2CH(R1)CONHC(R2)CONHCH(R3)CO2? → NHCH(R3)CO2H + NH2CH(R1)CONHC(R2)?C?O and NH2CH(R1)CONHCH(R2)? CONHCH(R3)CO2? → NH2C(R1)CONHCH(R2)CONHCH(R3)CO2H → ?NHCH(R2)CONHCH(R3)CO2H + NH2C(R1)?C?O. These fragmentations provide ready identification of the peptide. 相似文献
17.
Summary The chelation behaviour of the complexes of La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Y3+, Tb3+, Dy3+, Ho3+ with biologically active 2-Hydroxy-1-naphthaldehyde semicarbazone (HNAS) has been studied potentiometrically in 75% (v/v) dioxane-water medium at various ionic strengths. The method of Bjerrum and Calvin, as modified by Irving and Rossotti has been used to find out the values of n andpL. The formation constants of metal chelates and the values ofS
min have been calculated. The order of formation constants of chelates was found to be: La3+3+3+3+3+3+3+3+3+3+3+.
Physikochemische Untersuchungen zur Komplexierung von biologisch aktivem 2-Hydroxy-1-naphthaldehyd-Semicarbazon (HNAS) mit Lanthanoiden
Zusammenfassung Das Chelierungsverhalten von La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Y3+, Tb3+, Dy3+ und Ho3+ mit 2-Hydroxy-1-naphthaldehydsemicarbazon (HNAS) wurde potentiometrisch in 75% (v/v) Dioxan-Wasser bei verschiedenen Ionenstärken untersucht. Die Werte für n undpL wurden nach der Methode von Bjerrum und Calvin in der Modifikation von Irving und Rossotti bestimmt. Die Komplexbildungskonstanten der Metallchelate und die WerteS min wurden ermittelt. Die Reihung der Komplexbildungskonstanten war La3+相似文献3+ 3+ 3+ 3+ 3+ 3+ 3+ 3+ 3 3+.
18.
The 17O and 2H quadrupole coupling constants of rovibrational levels of 17O1H+, 17O2H+, and 16O2H+ in their X3Σ− state have been calculated from molecular wave functions that explicitly describe nuclear motion. The 17O quadrupole coupling is predicted to be strong and its vibrational dependence differs from that known for other nuclei A in the first-row hydrides AH or AH+. The deuterium coupling in 17O2H+ and 16O2H+ is found to be weak and its behavior is similar to that of other first-row hydrides. The change with rotational excitation is unimportant. The quadrupole hyperfine patterns of 17O2H+ in its ground state are dominated by the strong oxygen coupling. © 1996 John Wiley & Sons, Inc. 相似文献
19.
Dr. Xiaojiao Kang Prof. Wei Lü Prof. Hongcheng Wang Prof. Dongxiong Ling 《Chemphyschem》2019,20(6):861-867
A series of Ca9Ga(PO4)7:Ce3+/Tb3+/Dy3+/Mn2+ phosphors with tunable color, in which Ce3+ acts as the sensitizer, was synthesized. Energy transfer (ET) from Ce3+ to Tb3+/Dy3+/Mn2+ was investigated in detail. Tb3+/Dy3+/Mn2+ single-doped Ca9Ga(PO4)7 can exhibit green, yellow, and red emission, respectively. Incorporating Ce3+ into a Tb3+/Dy3+/Mn2+ single-doped Ca9Ga(PO4)7 phosphor can remarkably promote the luminous efficiency of the Tb3+/Dy3+/Mn2+ ions. This enhancement originates from an efficient ET from Ce3+ to Tb3+/Dy3+/Mn2+. The ET was validated by luminescence spectra, decay dynamics, and schematic energy levels. Moreover, the intensity ratio of red emission of Mn2+ to violet emission of Ce3+ was analyzed based on energy-transfer and lifetime measurements. In Ce3+-Tb3+, Ce3+-Dy3+, and Ce3+-Mn2+ doped Ca9Ga(PO4)7, the emitting color changed from violet to green, yellow, and red, respectively, which indicates the potential use of this new tunable phosphor in UV light-emitting diodes. 相似文献
20.
脯氨酸类衍生物结构独特,鲜有报道利用核磁共振(nuclear magnetic resonance,NMR)技术对氨基酸的手性进行鉴别.利用多种NMR技术:1H NMR、1H-1H同核位移相关谱(1H-1H COSY)、1H-1H质子全相关谱(1H-1H TOCSY)、1H-1H核Overhauser效应谱(1H-1H NOESY)、13C NMR、无畸变的极化转移增强法(DEPT135°)、1H-13C检出1H的异核单量子相干(1H-13C HSQC)和1H-13C检出1H的异核多键相关(1H-13C HMBC),对脯氨酸类N-酰胺衍生物两种构象异构体的1H和13C NMR进行了全归属,确定了室温下在二甲基亚砜(DMSO)中L型和D型的顺反异构体以相同的比例同时存在. 相似文献