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211.
212.
C.L. Liu X.Y. Wang Z.M. Wang S.S. Li C.T. Xin H.F. Wang B. Li L. Jiang 《Journal of Radioanalytical and Nuclear Chemistry》2001,250(3):587-591
The migration of 99Tc in a weak loess aquifer was investigated in-situ with undisturbed aquifer medium columns. The columns were obtained horizontally at a depth of 3236 m in an Underground Research Facility (URF). Quartz containing 3H (HTO) and 99Tc (in the form of 99TcO4
-) was introduced into one end of the columns and the columns were covered tightly. Aquifer water was introduced into the columns directly from an experimental shaft in the UFR. Effluents from the columns were collected and the activity of 3H and 99Tc were determined with a liquid scintillation analyzer. The breakthrough curves of 3H and 99Tc indicate that 99Tc migrates a little faster than that 3H does in the aquifer. 相似文献
213.
The title compound glycin·3,5-dihydroxybenzoic acid (GDB) has been synthesized and characterized by single-crystal X-ray analysis. It crystallizes in orthorhombic, space group Pca21 with a = 25.513(10), b = 4.668(2), c = 9.150(4)(A), Z = 4, V = 1089.8(8)(A)3, C9H13NO7, Mr = 247.20, Dc = 1.507 g/m3, μ(MoKα) = 0.132 mm-1, F(000) = 520, R1 = 0.0322 and wR2 = 0.0611 for 885 observed reflections (I > 2σ(I)). The title compound is a 1:1 molecular complex of glycin and 3,5-dihydroxybenzoic acid, which is linked by O-H…O and N-H…O hydrogen bonds to form a three-dimensional framework. Test of SHG (second harmonic generation) indicates that NLO generation of the crystal is higher than that of KDP. 相似文献
214.
The N,N-diisopropylaminomethyl aluminium compound [tBu2AlCH2NiPr2 x LiCl]2(1) and the gallium compounds Li[tBu2Ga(CH2NiPr2)2](2) and [tBu2GaCH2N(H)iPr2]Cl x tBu3Ga (3) were prepared by transmetallation of N,N-diisopropylaminomethyllithium LiCH2NiPr2 with di-tert-butylaluminium or -gallium chloride, and characterised by elemental analyses, multinuclear NMR spectroscopy (1H, 13C, 27Al, 7Li) and IR spectroscopy. The crystal structures have been determined by single crystal X-ray diffraction. Compound aggregates as a centrosymmetric dimer, with two Al-C-N units connected by a frame of two LiCl molecules [Al-Cl 2.367(1), Cl-Li 2.339(4) and 2.374(4), Li-N 1.977(4)A]. Compound 2 is a lithium organogallate with two weak LiN bonds [1.965(7) and 1.937(7)A]. Compound 3 contains two different moieties: tBu3Ga and a [tBu2GaCH2N(H)iPr2]+ cation, which are bridged by a Cl- anion [Ga-Cl 2.445(1) and 2.579(1), HCl 2.362(3)A]. 相似文献
215.
采用弱碱性阴离子交换树脂HJ-30对发酵液中1,6-二磷酸果糖的分离进行了研究。详细地研究了树脂的吸附和脱附性能。实验结果表明,HJ-30树脂对FDP的吸附量达0.28gFDP/g湿树脂,以0.05mol/LNaCl洗脱光机磷和1mol/LNaCl洗脱1,6-二磷酸果糖,产品的收率和纯度分别为92%和99.4%。 相似文献
216.
Ma B Chen Y Hao H Wu M Wang B Lv H Zhang G 《Colloids and surfaces. B, Biointerfaces》2005,41(2-3):197-201
Under the background of algae removal and growth inhibition by ultrasonic irradiation, the effects of ultrasonic irradiation on removal of Microcystis, the concentration variation of microcystins (MC) produced by Microcystis in Microcystis suspension, and sonochemical degradation of microcystins in water, were studied in the paper. The results showed that ultrasonic irradiation could efficiently inhibit the growth of Microcystis, and ultrasonic irradiation shorter than 5 min would not introduce the increase of microcystins dissolved in Microcystis suspension simultaneity. Also, microcystins dissolved in Microcystis suspension would not increase as ultrasonic power increasing. Further research showed that microcystins were effectively degraded in ultrasonic fields. After 20 min ultrasonic irradiation at 150 kHz and 30 W, the removal rate of microcystins reached 70%. 相似文献
217.
In this paper, the chronoamperometry was used to study the charging processes of polyethylenedioxythiophene (PEDOT) modified electrodes in the potential range where PEDOT was in the oxidized state. The results show that the charging behaviors of the PEDOT films are well agreed with the exhausted finite diffusion model. The dependence of the capacitance values of the films on potential and concentration of solution was also studied in this potential range. 相似文献
218.
A rapid and simple method, the so-called stearic acid method (SAM) was developed to prepare nanostructured TiO2/SnO2 binary oxides by combustion of stearic acid precursors. The preparative process was studied by Fourier transform infrared spectroscopy (FT-IR). During the preparative process, metal precursors were dispersed in stearic acid at molecular level. Microstructure of the samples was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), BET specific surface area measurement and the results were compared with those obtained by conventional sol-gel method. The photocatalytic decomposition of methyl orange was used as a model system to determine the relative influences of the preparation method and the concentration of SnO2 on the photocatalytic activities. It was found that preparative methods affected the crystalline structure of TiO2/SnO2 powders and the anatase phase of TiO2 was stabilized by the addition of SnO2 in SAM. The samples prepared by SAM showed better dispersity, larger specific surface area and the TiO2/SnO2 (r=0.15, SAM) catalyst showed higher photocatalytic activity than Degussa P25. 相似文献
219.
A reversed-phase ion-pair HPLC with indirect photometric detection for the simultaneous determination of sulfite, sulfate, hydroxymethanesulfonate (HMS), and other inorganic anions in atmospheric water has been developed. Separations were accomplished in less than 10 min in a cetylpyridinium-coated C18 column with 0.5 mM potassium hydrogen phthalate-0.015% triethanolamine-3% methanol at pH 7.9 as mobile phase. Quantitation was carried out by the peak area method, with detection limits in the pmol range. UV light absorption responses were linear over a wide concentration range from several hundred μmoles to the detection limits of each anion. The application of the method provides a rapid and efficient technique for the quantitative determination of sulfur and other inorganic species in atmospheric liquids. 相似文献
220.
采用动态TG-DTG,研究了铁催化剂的制备方法、前驱化合物的 种类及 热处理对其在碳-氧反应中催化活性的影响。观察到在干混法制备催化剂时,所用铁盐分解温度越低活性越高。此外还发现,热处理可明显提高由分解温度高的含氧铁盐制备的 催化剂的活性,但对于不含氧铁盐和分解温度低的含氧铁盐无影响。 相似文献