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91.
锂离子筛的制备及其交换性能研究 总被引:3,自引:0,他引:3
用浓度为0.5mol/L的盐酸对高温固相合成的前体LiMn2O4进行酸洗脱锂,制得锂离子筛HMn2O4,并在不同pH值和温度下进行了Li 交换性能的研究,同时运用XRD和TEM进行了相应表征。结果表明,锂离子筛吸附交换前后晶体结构只发生了细微变化,但都仍为尖晶石型结构;交换反应在前10min速率最快,约20min就趋于平衡;Li 交换总量随pH值增大而升高,其中pH=7时交换容量为18.5526mg/g;Li 交换量和交换选择性随温度的升高而显著增强。 相似文献
92.
Jingjing Xu Yidong Lu Baohong Liu Chunhe Xu Jilie Kong 《Journal of Solid State Electrochemistry》2007,11(12):1689-1695
An ultrathin, ordered, and packed protein film, consisting of the 2-mercaptoacetic acid (MAA), polydimethyldiallylammonium
chloride (PDDA), and wild-type (WT) photosynthetic reaction center (RC; termed as WT-RC) or its pheophytin (Phe)-replaced
counterpart (termed as Phe-RC), was fabricated by self-assembling technique onto gold electrode for facilitating the electron
transfer (ET) between RC and the electrode surface. Near-infrared (NIR)-visible (Vis) absorption and fluorescence (FL) emission
spectra revealed the influence of pigment substitution on the cofactors arrangement and excitation relaxation of the proteins,
respectively. Square wave voltammetry (SWV) and photoelectric tests were employed to systematically address the differences
between the WT-RC films and mutant ones on the direct and photo-induced ET. The electrochemical results demonstrated that
ET initiated by the oxidation of the primary donor (P) was obviously slowed down, and the formed P+ had more population as well as more positive redox potential in the Phe-RC films compared with those in the WT ones. The
photoelectrochemical results displayed the dramatically enhanced photoelectric performances of the mutant ones, further suggesting
the slow-down formation of final charge-separated state in Phe-RC. The functionalized protein films introduced in this paper
provided an efficient approach to sensitively probe the redox cofactors and ET differences resulting from only minor changes
in pigment arrangement in the pigment–protein complex. The favored ET process observed for the membrane proteins RC was potentially
valuable for a deep understanding of the multi-step biological ET process and development of versatile bioelectronic devices. 相似文献
93.
Liu H Zhang S Nie S Zhao X Sun X Yang X Pan W 《Chemical & pharmaceutical bulletin》2005,53(6):631-633
Methylacrylic acid/styrene cross-linked with divinylbenzene is a novel pH-sensitive ion exchange resin. Microspheres of this resin were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The microspheres showed a pulsatile swelling behavior when the pH of the media changed. The pH-sensitive microspheres were loaded with salbutamol sulfate and the drug-release characteristics were studied under both simulated gastric and intestinal pH conditions. The results obtained showed that the drug release also depended on the pH of the release media. 相似文献
94.
The effects of atomic multipole moments obtained by the potential-derived method on hydrogen bonding
A potential-derived atomic multipole method called the cumulative potential-derived atomic multipole method is developed, with which electrostatic atomic multipole moments are derived by fitting the molecular electric potential in a cumulative way. It is applied to the hydrides of N , O , F , S , Cl , and methanol and the hydrogen-bonded dimers formed between them. The relationship between atomic multipole moments and molecular charge distributions is found. The structures calculated with Buckingham's electrostatic model are in good agreement with experiments. The phenomena of nonlinear structures of most H -bonded complexes—the deviations of symmetry axes of electron donors from H bonds—and correct distinguishing between two alternative structures are attributed to atomic dipole and quadrupole moments. Compared with other methods, this method has a quantitative and qualitative advantage and simple algorithm. The main conclusion is that the atomic multipole moments play a substantial role, although a potential-derived charge model was deemed sufficient previously. © 1993 John Wiley & Sons, Inc. 相似文献
95.
The photoionization spectroscopy of Si(CH3)3Cl in the range of 50 -130 nm was studied with synchrotron radiation source. The adiabatic ionization potentials of molecule Si(CH3)3Cl and radical Si(CH3)3 are 10.06 ±0.02 eV and 7.00±0.03 eV respectively. In addition, the appearance potentials of Si(CH3)2Cl+, Si(CH3)3+, SiCl+ and SiCH3+ were determined:
AP(Si(CH3)2Cl+) =10.49±0.02eV, AP(Si(CH3)3+) = 11.91 ±0.02eV
AP(SiCl+) = 18.64 ±0.06eV, AP(SiCH3+)= 18.62 ±0.02eV
From these, some chemical bond energies of Si(CH3)3Cl+ were calculated:
D(Si(CH3)2Cl+ - CH3) =0.43 ±0.02eV, D(Si(CH3)3+ - Cl) = 1.85 ± 0.02eV
D(SiCH3+ - (2CH3 + Cl)) = 8.56 ± 0.06eV, D(SiCH3+ - 2CH3) =6.71±0.06eV
D(SiCl+ - 3CH3) = 8.58 ± 0.06eV, D(SiCl+- 2CH3) = 8.15 ±0.06eV
D(SiCH3+- (CH3 + Cl)) =8.13 ±0.06eV 相似文献
AP(Si(CH3)2Cl+) =10.49±0.02eV, AP(Si(CH3)3+) = 11.91 ±0.02eV
AP(SiCl+) = 18.64 ±0.06eV, AP(SiCH3+)= 18.62 ±0.02eV
From these, some chemical bond energies of Si(CH3)3Cl+ were calculated:
D(Si(CH3)2Cl+ - CH3) =0.43 ±0.02eV, D(Si(CH3)3+ - Cl) = 1.85 ± 0.02eV
D(SiCH3+ - (2CH3 + Cl)) = 8.56 ± 0.06eV, D(SiCH3+ - 2CH3) =6.71±0.06eV
D(SiCl+ - 3CH3) = 8.58 ± 0.06eV, D(SiCl+- 2CH3) = 8.15 ±0.06eV
D(SiCH3+- (CH3 + Cl)) =8.13 ±0.06eV 相似文献
96.
97.
98.
99.
8—氮鸟嘌呤的极谱伏安行为 总被引:4,自引:0,他引:4
用循环伏安法(CV)、电流采样极诸法(SCP,即TAST)、常规脉冲极谱法(NPP)、微分脉冲极谱法(DPP)、线性扫描伏安法(LSV)、Osteryoung方波伏安法(OSWV)和计时库仑法(CC)等电化学技术研究了抗癌药物8-氮鸟嘌呤(8-azaguanine,guanazolo,简称8-AG)的极谱伏安行为.在 0. 1mol/L H2SO4底液中,8-AG有一良好的还原峰,峰电位(Ep)在-0. 95V(vs.Ag/AgCl,下同)附近,8-AG浓度在4×10-6~8×10-4mol/L范围内.峰高与浓度有良好的线性关系,线性相关系数r=0.9999~0.9910,检出限为1× 10-6mol/L.实验证明了该峰具有吸附性.本文提出了电极反应机理,它包括:酸性介质中8-AG的质子化、质子化的8-AG在汞电极上吸附以及完全不可逆的两电子还原过程.同时用量子化学计算方法(全略微分重叠法即CNDO/2)对8-AG和鸟嘌呤的各原子的净电荷以及Wiberg键级进行了计算,从理论上解释了8-AG的电化学还原机理。 相似文献
100.
1—酰基—4—氯环己烷与取代芳烃的区域与立体选择性反应 总被引:2,自引:0,他引:2
从环己烯合成了1-酰基-4-氯环己烷,发现在其在AlCl3催化与苯,氯苯,溴苯等优先生成反式1-芳基-4-酰基环己烷,与联苯反应时选择性较差。 相似文献